texts: Image Processing Suite for bacterial microscopy: Schnitzcells or MicrobeTracker?

texts:
I am looking to start doing some work tracking the size and growth of individual bacterial cells in the microscope. In order to analyze the images I need software that can segment the cells, accurately determine their shape, and track cell lineages on a 'movie' of images collected from one experiment. Given the constraints of my microscope setup, the easiest thing for me to do is to use a strain of bacteria constitutively expressing GFP and segment the cells based on fluorescent intensity. This is functionally equivalent to segmented phase-contrast images of wild-type cells, i.e. I'm not that interested in changes in fluorescence or using fluorescence as a gene expression reporter, though my needs may head in that direction.

I don't want to reinvent the wheel (and I think that it's better if the community consolidates around a few programs that everyone uses so that experiments can be more comparable), so I'm looking for a previously published package that is robust and easy to use. Flexibility at measuring fluorescent tracking is nice, but at this stage is not crucial. The two packages that I have seen are Schnitzcells from the Elowitz lab at CalTech and Microbetracker from the Emonet and Jacobs-Wagner groups at Yale. Unfortunately they were released at the same time and don't provide a good comparison of the pros/cons of each tool.

Finally, my question is

  What are your recommendations for an image analysis suite (from the two packages above or another package you have used)?

Let me know if I can make my criteria more clear or anything else. Thanks!


texts: How can a chromosome translocation in somatic cells lead to disease?

texts:
Looking at this picture...

(source: nih.gov)

...I get the impression that the part of chromosome is attached to other chromosome, but it is not mutated. When we assume that all genes in the translocated part are intact and can still make mRNA, my question is:

How can a chromosome translocation in somatic cells lead to abnormality or disease?


texts: What is the cause of a protuberant belly in kwashiorkor?

texts:
Kwashiorkor is a PEM (Protein–energy malnutrition) usually characterised by a pot belly. Why is there a pot belly in the case of a malnutrition? I have found contradictory reasons. This paper says that it is due to a fatty liver. This website says it is due to excess fluid accumulation in the tissues.
I noticed that these children have very skinny limbs. When I pointed that out to my teacher a few years back, she told me that the subcutaneous fat from the thighs accumulates under the belly. I can find no source confirming that, though.
So, what is the cause of the pot belly?


texts: How do antioxidants affect human metabolism?

texts: I'd like to know how antioxidants affect human metabolism and which ones are essential for metabolic processes.


texts: Can methylation from DNA get copied to RNA during transcription?

texts: Methylation on gene-body and 3'UTRs if copied to mRNA can potentially regulate post-transcription modifications or expression regulation. But I'm not sure if they are maintained after transcription or if they get all de-novo methylation.


texts: Distribution of the number of synapses per neuron

texts:
There is a mean number of synapses per neuron in the human brain which is not very well known, but is of order 10,000. (Some say, it's about 6,000, other say it's about 50,000.)

  What is known about the distribution of the number of synapses - in a
  very rough sense?

The number is most certainly not distributed normally around one mean value of about 10,000 (because there are very different types of neurons).

More probable, there are some types of neurons with typical mean numbers of synapses (each distributed normally), which would give a distribution like this:

For the sake of simplicity I want to ask:

  If we were to group numbers of synapses roughly into bins of powers of
  ten, how high would be the peaks, roughly?


texts:
Listening to really good music right now, I was wondering why it raises goosebumps.

Is there any physiological reason for this reaction to specific wavelengths or something?

EDIT:
Due sometimes strong vibration, roadwork for example,  raise goosebumps too I reckon it's about the wavelengths but if someone could explain what is happening and why, that would be great.

CROSS-POSTED


texts:
The video Ear rumbling happens below the range of human hearing demonstrates that the "ear rumbling" sound is actual sound and can be recorded by a sensitive microphone near the ear.

What is it exactly that produces this vibration and how is it radiated as sound waves into the air?

If it is subsonic, then why does it sounds like noise rather than being inaudible?


texts:
Fats are fatty acids joined onto the backbone of a glyercol (propane-1,2,3-triol).

Why was glycerol seemingly chosen by nature to be the backbone of fats? Why can't it have been a butane -1,2,3,4- tetraol or pentane with 5 alcohol groups or almost any other molecule?

So my question boils down to, is it just pure chance that glycerol is the backbone of fats or is there a deeper underlying reason?


texts: How are whole Haplotypes for Sequencing isolated?

texts: Is it possible to reliably isolate and amplify DNA from individual sperm and/or eggs (from a fish)? I'd imagine that the small amount of DNA would make the PCR a bit wacky. We've considered irradiating sperm and attempting to create haploid females via gynogenesis, but I was wondering if there was a faster and easier method that could utilize gametes directly.


texts: RNA product storage in isopropyl alcohol

texts:
I have an issue. I isolated RNA from cortex a few days ago. For isolation of RNA i used this procedure:

I homogenizised my sample (mouse cortex) with Trizol. Then to the sample add chloroform, shooke and centrifugate it. After this part i took away the aquatic phase with RNA from mixture and add it to the eppendorf tube with beforehead prepared isopropyl alcohol with glykogen. Again i shook and centrifugate it. In this part i removed isopropyl and let only RNA pelet. Afterwards i did same thing with 75% ethanole. Last but not least i dissolved the pellet with DEPC, checked its concentration on nanodrop.

From nanodrop i saw that one of the sample had been contaminate with guanidine isothiocyanete. So i just desided to repeat steps od my isolation from isopropyl alcohol. To increase precipitation of RNA and increase chance od decontamination i decided to let RNA in isopropyl alcohol precipitate in -80 °C freezer for a night. Unfortunately i fail to remember it untill now.

My question is: Will it affect any integrity of my RNA sample?


texts: What is the minimum number of chemical elements required for life on earth? Does it vary between kingdoms?

texts:
As a non-biologist, I assume that there are certain elements that occur in all life forms as we know them. Examples might be carbon, hydrogen, oxygen and so forth. There are also elements that are rarely, if  ever, required for life on earth. My question is not about what elements might be required for life (although such information might be interesting for me and other readers). Rather it is about what the minimum possible number of elements that any life form on earth has, if we know the answer to that question. Also, if it is known, (how) does this differ between the plant, animal and other kingdoms?

You are far more likely than me to know what tags might be appropriate here. Please feel free to edit.


texts:
More or less we humans are around 1.70 meters tall.

My question is, would it be possible to scale us? that is, is it in principle possible having humans 1 cm tall, or 10 meters tall or is there some reason that makes our height somehow ideal?


texts: Can you please identify this beetle? (Rajasthan)

texts:
I thought that it was dangerous and kept it under a polythene at my home, in Rajasthan.

Is this insect harmful, rare or common? If the pic is not clear, I would like to mention that it is green, six-legged and its body is separated in two from the neck.


texts: Are there any benefits/disadvantages/traits from having a permanent lower core temperature?

texts:
My body temperature as far as I remember has always been around 35.6 degrees Celsius, that's a degree less than what is the usually quoted as the average temperature for humans.
Are there any known correlations such as a shorter/longer average lifespan or pronounced traits such as being more sensitive to warmer temperatures or later/earlier onset of hypothermia symptoms?

Or is it not low at all or low enough to have any noticeable effects.


texts: Why we can't feel the different parts of ear during hearing which is mentioned in all biology books?

texts: We can't feel our outer ear, middle ear and inner ear during hearing something. Why is that such a complex phenomenon is happening all the time but still we don't have any clue regarding that in our practical life?  We just get the sensation of hearing something and get no sensation/feeling how  different parts of our ear work all together .why all these happening within our ear and we never conscious about them ? In fact , we can know them only after studying biology.


texts: How do trees communicate in the "Wood Wide Web"?

texts:
I read on The New Yorker - The Secrets of the Wood Wide Web that trees communicate with each other through electrical impulses sent through their roots. Through these impulses they can ask other trees for some nutrient if they are getting it in insufficient amount or warn the other trees about an upcoming pest attack. This phenomenon is termed as the Wood Wide Web.

So how do trees distinguish in different types of impulses that they receive if they don't even have a brain? And does this process show any resemblance to nervous system in animals?

Additional YouTube video: Trees can talk to each other, but how?


texts: Recommend any Molecular lab LIMS (Laboratory Information Management System)

texts:
We are looking to develop or customize a LIMS for our molecular lab. Do you know of a LIMS that you've used in a molecular lab before, or one that could be used.

Thanks for the help

(Edit)
Some of the attributes we'd like to store include:
    Patient information (Name, demographics, test ordered)
    Sample information (Accession #, Case ID, sample type (blood,bone, etc.) )
    Test information (Kit used, Kit lot #, associated expiration date)
Ideally this is Software as a Service so its usable on multiple operating systems.


texts: I saw this jellyfish at Brighton Beach, Victoria, Australia. I have searched jellyfish images but there is nothing similar. It is round with a diameter of approximately 80cm and the blue part looks like hundreds of thin tassels.


texts: What causes a group of disembodied neurons in a dish to fire after a silence? If there are no neurons providing a stimulus for more firing (as in a dish of disembodied rat neurons), then why don't they simply cease firing after the synchronized burst completes?


texts: Is disease transmisson through milk consumption or meat consumption considered direct or indirect transmission route?

texts: From an epidemiological point of view, is consumption of raw milk or meat considered as indirect or direct transmission ? Let's take the example of bovine TB. Is consumption of unpasteurized milk considered as direct or indirect ? IMO since milk is a tissue (liquid tissue but still), it is part of the cow, then how could you go more direct than eating the infected animal ?


texts: Can DNA produce ribozyme-like structures?

texts:
RNA is known to act as an enzyme via its ability to fold itself in specific ways.

Is DNA capable of such structures? Or is it some biochemical reason stopping the folding?
Have they been observed in nature?


texts: Trichloroacetic Acid (TCA) is commonly used for protein precipitation but the wash waste needs to be neutralized prior to disposal. What exactly is required to effectively neutralize TCA waste? Do I just add caustic?


texts:
Can anyone identify this insect found in the North East of the United Kingdom, July 2019. About 3-4cm long.

Could this be a wood wasp?

Thanks.


texts:
It is unusual to see such size spiders in Lithuania, so I was wondering what kind of spider it is and if it is strong enough to bite through humans skin.
I've googled for biggest known spiders in Lithuania, but mentioned few species don't look alike - mine has way thinner legs, but I'm not an expert.
I've placed 1 euro cent coin for size - it's diameter is 16.25mm


texts: What is the name of the bond between phosphate and the sugar in a nucleotide?

texts: I am slightly confused about what the name of the bond is between the phosphate and sugar within a nucleotide. All my research comes up with is a phosphodiester bond being the backbone of DNA. But within a single nucleotide, would we perhaps call it a phosphoester bond (all of my searches of phosphoester bond correct it to phosphodiester, so I don't think the term 'phosphoester' is in use...); or maybe it would be an O-glycosidic bond as it is a sugar molecule covalently bonded to another molecule via an O atom?


texts: What is the point of having evolved two nostrils?

texts: How would having two nostrils be advantageous to your sense of smell or your ability to breath? I already hypothesized that either one of the nostrils could act as a back up for when another gets congested, but even then you can still breath through your mouth and at least for me I almost always have either both nostrils congested or neither at all.


texts: Besides fruits and milk, what other things in nature are "intended" to be eaten?

texts:
Besides fruits and milk, what other examples are there in nature where it is beneficial for a species to have some part of its biomass eaten by others so that it evolved to produce nutritious parts to be eaten by other organisms? For example, plants having animals eat their fruits as a means of transporting their seeds.

Update.

I think there are at least two philosophically different scenarios that interest me.

One is when the substance is intended to be eaten by the same species (example: milk).

The other is when it is intended to be eaten by another species (example: fruits).


texts: Why does the inhibition of translation initiation cause the accumulation of 80S ribosomal monosomes?

texts:
As I have read in (1), inhibition of translation initiation will increase the number of 80S ribosomes while decreasing the fraction of polysomes due to the polysome-runoff. The net effect is to decrease the polysome/monosome (P/M) ratio and we observe it for example by inducing ER stress by tunicamycin in (2).

I understand the reduction in polysomes - since we don't interefere with elongation, polysomes work as normal, fallling of eventually, but new monosomes cannot proceed to polysomal stage due to inhibited initation.

However, why do the 80S ribosomes accumulate? I have always thought that 80S ribosome is always bound to mRNA, otherwise it dissociates as separate 40S and 60S subunits. Does this effect therefore mean that the accumulated 80S fraction is mRNA-free and therefore "vacant 80S ribosomes", as decribed in (1), can exist?

Thanks a lot!

https://books.google.co.uk/books?id=6sEq1xLu_hcC&pg=PA130&lpg=PA130&dq=polysome+translation+initiation&source=bl&ots=Un6JjImBJX&sig=ln9mn0KoJDJaVOGK8LbrEmMz9XE&hl=cs&sa=X&ei=x2JiVci8N4jX7Ab02YLgBQ&ved=0CGQQ6AEwCw#v=onepage&q=polysome%20translation%20initiation&f=false
http://jcs.biologists.org/content/115/11/2443/F4.large.jpg


texts: I came across this question today. In the B diagram, zoospores of chlamydomonas is given. Now my doubt is, are the zoospores formed by multiple fission or spore formation? If it is by spore formation, isn't spore formation and multiple fission the same thing when it comes to unicellular organism i.e chlamydomonas? If it is the same thing, why isn't option c correct in the question I attached?


texts:
I've got a project where we collect leaves, classify them, etc. There are some required classifications. One of the requirements is to get a doubly-compound leaf. What are some trees that are doubly-compound? Please help! I have Hickory, but that's just compound I think.

Edit: I did try googling, but it's hard for me to know what's available in my region.

From Comments: I live in Tennessee, U.S.


texts: Can you change your gut microbiota by changing your diet? Would that affect calorie uptake?

texts:
I have seen peer-reviewed papers mentioning the daily changes in gut microbiota composition according to dietary changes. See for example this paper:

http://genomebiology.com/2014/15/7/R89

My question is related to this one:

Relationship between our microbiome and personalized nutrition

If, according to these recently published scientific results, it takes a day to change the gut microbiota to adjust to the dietary change, and the presence of certain microbes makes food assimilation more effective,

Does this mean that alternating a protein-rich meat and dairy diet with a carbs-rich diet every day would make our microbiota switch daily and not have time to increase calorie uptake?


texts: Lifetime of secondary messengers such as Calcium or IP3

texts:
Can anyone suggest me literature on the lifetime of secondary messengers such as calcium or IP3? A book would be preferred. What I am specifically looking for is a validation that secondary messengers have a certain lifetime and undergo degradation. I need not know specifically how long their lifetime is but rather interested in the fact that they do undergo biodegradation.

[EDIT]: Replaced the word 'biomolecule' by 'secondary messengers' as per the suggestion of @WYSIWYG to narrow down the answer.


texts:
My textbook says “Among K+, Na+ and Cl-, K+ contributes to the resting membrane potential the most, because it has the greatest permeability across the membrane.”

I agree with this, but I’m just curious: why is the equilibrium potential of Cl- (-75mV) closer to the resting membrane potential (-70mV) than that of K+ (-90mV)?


texts: What are the structural factors affect enzyme's Km?

texts:
Is there any rules (should not be exact), to estimate the kinetic changes in an enzyme if I did any mutation on it?

If I cannot estimate the new kinetic values, is it possible at least to clarify or suggest any explanation for the new kinetic after mutating an enzyme depending on the point mutation I did on it?

So I want to explain the changes in the kinetic parameters (Km / Vmax) in my enzyme after mutating it, maybe depending on the 3D structure? or the charge/size of the new amino acids? Or any other factors I may use to suggest anything logical how and why those changes happened to my enzyme after mutating it?

I need that for my dissertation and I am still totally lost, any ideas (with the proper references) will be great. I really appreciate any help.


texts:
I at times have many goats grazing in our locality. Recently a few cows were seen too. I just offered one of the cows a few leaves from Jasminum sambac plant growing in our garden. The cow smelled and left those leaves untouched. However on being given mango leaves, not a bit of it remained. The same situation did I observe with goats.I have the following questions:

What is the difference between leaves of others and leaves of Jasminum sambac?
Why do herbivores avoid consumption of these leaves?
Does it happen with other leaves too?


texts: With CRISPR-Cas9 I have conducted a targeted knockout of a DNA region encoding a certain protein (working with leukocytes). My question is, how long does it take until this protein is not detectable any more (e.g. via surface staining + flow cytometry) after the DNA has been manipulated? Or in other terms: how often are transcription, translation etc. taking place?


texts: Why can't the immune system start at the mating time?

texts:
The immune system has a great role in our body. When foreign particles
enter our body, the immune system can recognize and start
defense mechanisms such as the complement system and others. But when sperm enters
into the female organism, why does her immune system not recognize this?
In that time which kind of mechanism is active in the woman's body?


texts: Does cheese contain cells of animal stomachs?

texts:
When cheese is made with calf rennet, is it possible that the cheese contains cells of this calf (stomach)?

Dried and cleaned stomachs of young calves are sliced into small pieces and then put into salt water or whey, together with some vinegar or wine to lower the pH of the solution. After some time (overnight or several days), the solution is filtered. The crude rennet that remains in the filtered solution can then be used to coagulate milk.
Does this filtering exclude all stomach cells of the calf?


texts: How to get the correct RefSeq Protein transcript for a given RefSeq Nucleotide transcript?

texts:
How to get versioned Protein Accession Number for a Refseq Accession Number?

I have some versioned RefSeq Accession numbers and I would like to know their corresponding Protein Accession Numbers.

According to the RefSeqFAQ   http://www.ncbi.nlm.nih.gov/books/NBK50679/#RefSeqFAQ.what_causes_the_version_number there is not a 1-to-1 mapping between these numbers.

  Also, nucleotide (NM_, XM_) and protein (NP_, XP) records for the same
  transcript may not have the same version number after an update. For
  example, an update to the 5’ UTR of a RefSeq nucleotide record would cause a version number change for the updated nucleotide record but not for the corresponding protein record. Conversely, a change in the annotated start site of the coding sequence without a change in the underlying nucleotide sequence would cause a version number update for the NP_ but not for the NM_.

I have tried this, but it gives me a huge

>>> from Bio import Entrez
>>> Entrez.email='email@example.com'
>>> f = file('entrez_NM_005529.5.txt', 'w')
>>> print >>f,  Entrez.efetch(
...     db="protein",id="NM_005529.5", rettype="native", retmode="xml").read()

The XML results contain the Protein Acc No, <Textseq-id_accession>NP_005520</Textseq-id_accession> but there is no version specified. Is there a simple way to get obtain the matching protein transcript version?


texts:
When tired and it was dark, I noticed that if I focused on a dim light source and moved my eyes fairly rapidly sideways, the resulting images that lingered for a short while were not smoothly blurred together, but were discrete.

I assume this is not due to the brain's inability to process the data fast enough or the retinas not repairing fast enough when light breaks part of them down, so I am lead to the conclusion that eyes (if not generally, sometimes) move in very small sudden jolts rather than smoothly.

Is this correct? What is the reason for this (is it due to the eye muscles being unable to sustain motion for a long time, or something to do with the mechanics of the eye)? Was this result anomalous?


texts: Cell Respiration and Oxidative Phosphorylation

texts: Why and how does the proton travelling through the stalked particle in the inner mitochondrial membrane, cause a conformational change in the ATPase?


texts: What is happening at the electrode interface when the electrical field is modified due to the change of ion concentration after an AP?

texts:
I have been working for quite a while now on electrophysiology and electrode fabrication.

I studied what is happening at the neuron level during an action potential (polarization/depolarization, change in ion concentration inside/outside the cell membrane) as well as the interface electrode/electrolyte (double layer, electrical model of an electrode, etc...), but I am still struggling to tie all of those principle together.
My question is, what is actually happening when an electrode is recording an AP (extracellular recording). To my knowledge, this is what is happening:

AP triggered, change of ion concentration outside the cell membrane.
As the ion concentration is modified, electrical field is modified around the cell

My question is now, how does the electrode record this change of electrical field? In almost all of the literature, a simple, but unexplained, shortcut is usually done: the authors usually speak about the change in ion concentration and then directly link it to a "change of potential at the electrode", but how can we explain this change of potential? What is happening at the electrode interface when the electrical field is modified due to the change of ion concentration after the AP? Is there any current flowing inside the electrode?

Thank you in advance


texts: Why do universal recipients (AB blood group) not react to antibodies in the blood of O-group donors?

texts:
While studying compatible blood groups, I found that we only consider the antigens on red blood cells (RBCs) and not the antibodies present in blood plasma. For example

  “an AB blood group person can receive blood from persons of any blood group as there are
  already both antigens, A and B, on the RBCs.”

But why don’t we consider the antibodies already present in the plasma from people with different blood groups?

For example, the O blood group has both anti-A and anti-B antibodies. If this blood is given to an AB person who has antigens A and B, do the antibodies of O not react with the antigens of AB?  Or, in other words, how is a person with the AB blood group a universal recipient if he has both antigens(A,B) in the blood, which can react with antibodies(anti-A and anti-B) present in indiduals of other blood groups (A, O, B)?


texts: Is bootstrapping an acceptable way to determine standard error for binding constants?

texts: I'm measuring binding constants my system and I appreciate the usual methods of using replicates to measure standard errors and using those errors to calculate propagation of error. I'm curious if bootstrapping is a reasonable alternative to calculate uncertainty?


texts:
After reading a textbook chapter on GPCRs I am still confused by what regulates cAMP.

I took in my notes that cAMP is made by adenylyl cyclase and destroyed by cAMP phosphodiesterases (also another question within a question, are phosphodiesterases the same as phosphatases?)

So is cAMP regulated by GPCRs or is it regulated by cyclic AMP dependent Kinase A (PKA)?

I did find this article, but I'm not sure if I am understanding this correctly to answer my own question, but it seems like they are saying GPCRs regulate cAMP?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2720142/

Thanks


texts: Is there any source for raw data of SNP genotype frequency?

texts: On sites like SNPedia, some pages contain the frequency of the SNP in question in different populations, based on published research. I'm trying to write a script that takes 23andme data and compares it with SNP frequency to find rare SNPs that the user possesses. I'm thinking that the only way to do this might be to scrape it from a SNP database. Is there anywhere you know of that makes this information available in a more accessible format, ideally preformatted for parsing?


texts: Does GABA enhance or inhibit negative effects of glutamate?

texts:
A study on NCBI studied the correlation between a depressive mood and chronic pain. I researched this because today I noticed unusual emotional volatility as a result of 2 days of acute back pain combined with acute muscle soreness (DOMS).
I am certain that the pain and difficulty sleeping (although I slept in on both days), and challenges with finding a sleeping position without pain, and continuous pain on most moving, standing, and sitting, that this has caused some emotional volatility on a physiological level. (Psychological effects as a direct result of temporary chemical changes in the body/brain due to acute pain; not due to neural pathways causing depression, of which I do not have, and I am a joyful person normally).
This question is not about alleviating pain, as it will go away on its own soon. The back is getting near healed by end of week and the sore muscles which have DOMS due to intense workout will also resolve on its own in a few days to a week.
Rather, my question is specifically concerning a particular phrase which I am unclear about:

Glutamatergic activity can be promoted through the breakdown of efficient inhibition of the actions of glutamate by GABA

I am unclear if this is stating that GABA reduces the effects of glutamate or if it enhances the effects.
There is no clear answer to my full [temporary] issue, since the study itself states that neither the corresponding pathophysiological mechanisms of chronic pain and depression nor their mutual correlation has been identified, so there is no pathophysiological scientific answer to the chemical workings, so I can only speculate.
The end result is I wanted to discover whether increasing or lowering GABA could have any effect on my mood as a result of my pain in the short term, which is easily experimented rather safely by either taking GABA or taking a supplement that inhibits GABA. It could have no beneficial effect - no problem. It's worth a try though. I've taken GABA before BTW.
To reiterate the particular question: With regards to the statement:

Glutamatergic activity can be promoted through the breakdown of efficient inhibition of the actions of glutamate by GABA

Does this imply that GABA enhances or reduces glutamatergic activity?
Note:
I think it's saying that GABA creates glutamatergic activity which inhibits the neuroexcitatory effects of glutamate. That is, taking GABA would decrease effects of glutamate. Let me know if this is correct or not.


texts: Alternatives to TBE buffer for denaturing polyacrylamide gel electrophoresis of DNA and RNA?

texts:
I just stumbled upon an article promoting 10 mM sodium borate as an alternative to the well-known TAE and TBE buffers for agarose gel electrophoresis of DNA (Brody & Kern, 2004). They claim that sodium borate outperforms TBE and TAE at high-voltage conditions due to the significantly lower heat development.

I'm currently using TBE buffer and gels with 7M urea for my denaturing PAA gels, and I'm wondering if there are similar alternative conditions for those denaturing PAA gels of nucleic acids?

I couldn't find anything on using sodium borate for denaturing PAA gels, so I'm wondering if it should work the same as for the agarose gels or if it just isn't a good buffer for that kind of gel.

Brody, J. R. & Kern, S. E. Sodium boric acid: a Tris-free, cooler conductive medium for DNA electrophoresis. BioTechniques 36, 214–216 (2004).


texts:
My father-in-law claims that since plants need nitrogen to produce proteins, and since ammonia is NH3, that Ammonia should be fine for the plants, since it's just nitrogen and water and hydrogen, according to him. We were cleaning a rusty chain and a bunch of spilled into our garden. I'm talking about household ammonia.

Is that true?

I'm thoroughly convinced he is an utter idiot but then again he could be right since he does say he minored in Chemistry in his college days.


texts: Do drugs' levo isomers have a better interaction with the receptors in our body than dextro isomers?

texts: Examples of levo drugs include levothyroxine, levocitrizine, and levodopa. Is there any specific reason why the receptors in our body exhibit this stereoisomerism and hold a high preference for the levo isomer form of any drugs?


texts: What is the functional difference between hemoglobin and ferritin?

texts: I read that both hemoglobin and ferritin are for storing iron in the body. So, what is the difference between them in terms of storing/binding iron?


texts: The effect of salt, pH and temperature to the salivary amylase

texts:
If I prepare the following set of tests, incubate for 15 mins, then add 2-3 drops of iodine solution to each test tube:
Salt test (1ml starch solution + 0.5 ml enzyme + 1ml 1M NaCl, incubate at 37 oC
Acid test (1ml starch solution + 0.5ml enzyme + 1ml 0.5HCl), at 37oC
Alkaline test (1ml starch solution + 0.5ml enzyme + 1ml 0.5M NaOH), at 37oC
Temp test (1ml starch solution + 0.5ml enzyme + 1ml H2O), place in water-bath
(75oC)

What is the effect of salt, pH and temperature to the salivary amylase? I don't know what exactly how salt effect.
high temperature will denature the enzyme.

How about salt?


texts: What causes bacteria to change their proteins to become resistant to antibiotics?

texts: FMRSA (meticillin-resistant Staphylococcus aureus) became resistant to penicillin by a change in its DD-transpeptidase. What triggered this change? Did it happen by chance or does the bacterium have some sort of response mechanism to cause this change on detecting penicillin?


texts:
Antioxidants such as ascorbate and glutathione serve to inactivate radicals and counteract spontaneous oxidation reactions, such as unwanted disulfide bonds in proteins. These systems are cycles, where a "spent" antioxidant (say, oxidized glutathione) is convert back to its reduced form by another reducing agent, usally NADPH.

My question is, how much NADPH (or reducing equivalents) does a cell devote to this antioxidant defense? What is the flux, in molar amounts per unit time, through these systems? Does it represent a large portion of the energy metabolism of cells?

I am guessing that the flux is quite large, but I have never seen any data on this. Most likely it varies a lot between cell types, but I would be happy to see any numbers. I think this is important for understanding antioxidant chemistry in cells, yet it is rarely discussed in the literature.


texts: This large white spider has made her home on our garage. We live in the upper peninsula of Michigan. I believe it's an orb spider but couldn't find any with the large black almost hourglass shape on the back


texts:
Yesterday evening I found this baby bird in one corner of my house's verandah on the floor. I picked it up and placed it safely in a tray hoping that tomorrow morning its parents will find it (actually I initially suspected it to be a sparrow hatchling). When I saw it today morning I found that it is probably a bird of prey. As you can notice the large long beak and claws.
I'm really confused now what to do with it. Please suggest something.

EDIT

I live in Uttar Pradesh, India.
Its relatively plain where I live. (No mountains or lake nearby)
Temperature: 35-20 degrees Celsius
Added a photo for size estimation


texts: Can body temperature affect the quality of sleep?

texts: If so, how does it influence our sleep? And what can we do to improve the quality of sleep by adjesting our body tempurature?


texts: Do human women smell different before they enter labour?

texts:
Surfing youtube I found a video where a cat shows a protective behaviour towards a pregnant woman soon to enter labour.

In the miriad of average (dumb) comments I found another person stating that her cat felt precisely (via olfactory means I guess) that her (the woman's - not the cat's) day had come to give birth and started acting weirdly.

Do mammals leave a clear olfactory footprint before labour? And is this footprint noticeable by cats and dogs?
Is this definetely myth? Is this something yet to study? or is this something well known?

If the latter is the case: is it based on the sense of smell? is there anything to read to study the topic?


texts: What is this insect species? It lives in damp places in a cocoon like structure and can protrude its head from both ends

texts: Lives in damp places and can protrude head from both directions, 1 cm long approximately


texts: Are there any flowers that look like snakes?

texts:
In Rio 2, they showed a flower that almost looks like a snake head (with two fangs and a long tongue).

Are there any such flowers in real life too?


texts: What's the proper way to determine whether dose response curves +/- another variable (besides dose) are statistically different?

texts:
I have an experiment wherein I measured uptake of a certain molecule into cells when delivered using Carrier A vs Carrier B. In other words, for example, I delivered 1, 2, 3, 4, 8, and 10 nmoles of DrugX to 6 wells of cells per dosage, HOWEVER in 3 wells DrugX was delivered using Carrier A and in the other 3 wells DrugX was delivered using Carrier B. I would like to statistically determine whether the dose-response curve I get when I used Carrier A for delivery is any different than the dose-response curve I get when I used Carrier B for delivery.

My initial thought was to run a paired T-test, but then I realized I would have to report results at each point and I would like to report on the curve as a whole. My next thought was to use a two-factor ANOVA, however from what it looks like, when it determines whether or not there is variance due to the change in carrier it looks at the average and variance of all the responses. Another thought I had would be to calculate area under the curve, but I'm not sure how. I finally settled on running a nonlinear regression on the Carrier A data, then on the Carrier B data, then as the dataset as a whole and compared the resulting fit curves. I got a nice p-value, however the $R^2$ values are lower than I'd like (about 0.9) because the curves didn't model especially well.

What would you do? What is the industry standard?


texts: how does one apply for masters in genetics abroad?

texts: Please can some one give me step wise instructions for applying for a masters degree in genetics or biological sciences?


texts: By what method do ants dissect and hold soil

texts:
Not sure if this is the correct stackexchange site - please migrate/advise as you see fit.

I'm interested in the method by which ants "break off" a small amount of soil and then hold it in their jaws (?).

To clarify I know ants break off soil in small quantities, so that a single ant carries very little soil; I'm interested to understand what exactly how this happens. For example does the ant literally pick the soil directly, or does it brush it loose first etc. Further to this I'd like to know how the ant holds the soil. Is it akin to the soil being atop a palm, or more like being held between two hands?

Broader context: I'm looking into making a model of this type of soil movement and I wanted a more detailed understanding.


texts: How can a plant become resistant to glufosinate?

texts:
From Wikipedia, the mode of action of the non selective herbicide Glufosinate is:

  Phosphinothricin is an glutamine synthetase inhibitor that binds to the glutamate site. Glufosinate-treated plants die due to a buildup of ammonia and corresponding decrease in pH in the thylakoid lumen, leading to the uncoupling of photophosphorylation. The uncoupling of photophosphorylation causes the production of reactive oxygen species, lipid peroxidation, and membrane destruction.

Now, in this article from the University of California (Weed control, management, ecology, and minutia), it states:

  Researchers in Malaysia reported a few years ago on a population of goosegrass resistant to glufosinate in vegetable and orchard systems (Lee L J & Ngim J (2000). A first report of glyphosate-resistant goosegrass (Eleusine indica (L) Gaertn) in Malaysia. Pest Management Science, 56, 336-339).  For a number of years this was the only reported case of resistance to this herbicide.

What would have to happen in the weed for it to become resistant to this chemical/mode of action, and what would initiate this process?


texts: Which bird species/families worm-dance and is this learned behaviour?

texts:
Today I saw a Herring Gull and a Common Gull (UK common names) "worm-dancing" on an area of wet grass. Worm-dancing is when the bird taps its feet on the ground rapidly in order to drum worms to the surface (that its a worm hunting behaviour might be conjecture, I'm not sure it's been proven).

Shortly after, a pair of Jackdaws landed and also began hunting, but without dancing. They walked over the area poking about in the grass, whereas the gulls stayed in the same place.

So my question is firstly, which species/families has worm-dancing been observed in, and secondly is this thought to be learned behaviour (this might be determined by it being a local phenomenon in certain populations)?

EDIT: Originally misidentified a common gull as a black headed gull (corrected above). Today I saw a black headed gull alongside the two larger gulls, and it was hunting like the jackdaws, not worm-dancing. There might possibly be a size/weight requirement to be able to worm-dance effectively, if we accept the hypothesis that it's a method of bringing worms to the surface.


texts:
I have a mixture plasmids and undesired short linear fragments that share the same sequences. During denaturation and annealing, I would like the plasmids to 'find each other' before annealing to the shorter linear fragments. Assuming the concentration of shorter fragments is significant, is there a temperature profile to bias towards re-annealing of longer DNA?

More specifically, this is for a variation of the Surveyor Mutation detection assay, where re-annealed DNA with mismatches are digested, leaving non-mutant DNA intact. I would like to keep non-mutant plasmids for E. coli transformation. However, some linear fragments  ~10-50% of the length of the plasmid have escaped exonuclease treatment and would compete with the plasmids during annealing.


texts: At which end does polymerization of microtubules occur?

texts: My book says that polymerization and depolumerization of microtubules occurs on the + end however, I've found a note that says that depolymerization occurs on the - end. I need help please :) thank you


texts: Found Skull(?) in Ontario Canada, help identifying please

texts:
skull?...now maybe thinking its a bird pelvis?...(I don't know thats why I'm here!)on the beach in Northern Ontario Canada, have been wondering what it is. Any ideas? As you can see it is very small, fits in the palm of my friends hand.

Thanks so much!

Kimberley,


texts: Are synaptic boutons always located on axons?

texts:
I am learning about the protein Synaptophysin and I have read that it is an integral membrane protein localised to synaptic vesicles. I have also read that it is a specific and sensitive marker for synaptic terminals. On this site, I have read that synaptic terminals are the presynaptic endings and on Wikipedia that the presynaptic axon terminal is also known as the synaptic bouton. From what I have read online it seems to me that synaptic boutons are located only on axons.
However, I have found out about dendrodendritic synapses which are connections between the dendrites of two different neurons. Can the presynaptic ending of a dendrodendritic synapse be referred to as a synaptic bouton or are synaptic boutons only located on axons? Any insights are appreciated.


texts: Why is pollen used as a dietary supplement?

texts:
Sporopollenin is the hardest biological substance and can't be degraded by any know enzyme (my school textbook). Then why is pollen used as a dietary supplement if it can't be digested?

Also, pollen depends on nutrients from the plant itself either before or after pollination (before if pollen leaves anther at 3 celled stage and after if it leaves anther at 2 celled stage). Then how would it be rich in nutrients?


texts: What is the striking speed of a Green Anaconda?

texts:
How fast does a green anaconda strike? The striking speeds of other snakes is readily accessible, but not that I can find for the anaconda.

If you have information for the size and weight of the anaconda, please include this with your answer. Any additional information about their striking is also welcome.


texts: Does direction relative to origin of replication matter on small plasmids?

texts:
The recent question about forward vs. reverse strand got me thinking about directionality conventions in synthetic biology.
As noted in the answer to that question, if we consider only DNA in isolation, the strands are symmetric and there is no reason to prefer one over the other. A great deal of work in synthetic biology, however, is done on small plasmids, and there is definitely a directional context for these systems: the origin of replication.
The origin of replication is typically separated from the insertion point in an engineered vector, but the replication process is directional and goes around the whole plasmid. I am thus thinking that there may in fact be a difference in behavior caused by the interaction of transcriptional activity and the replication process, especially for a high-copy plasmid, where replication is much more highly active.
Does anybody know if this is, indeed the case, and to what degree is it worth being concerned about?


texts: What color does the other cone in Tetrachromacy correspond to?

texts: Human with normal vision possesses 3 cones, which correspond to blue (S), green (M) and red (L). What about tetrachromacy, where people have 4 cones in their retinae? What is the fourth cone exactly, and what color does that other cone correspond to?


texts:
Strong alcoholic beverages (e.g. moonshine) are reported to have caused blindness amongst some people.

How exactly can alcohol make someone go blind?

Is that because different forms of "rubbing" and homemade alcohol: ethanol, methanol, isopropyl and moonshine cause damage to the optic nerve?

Disclaimer: I am interested in what exactly is the biological process of certain alcohols on the optic nerves and what in particular triggers the blindness.


texts: A program for cell motility assessment with a batch process function?

texts:
Cell motility assessment is a branch of experimental biology or medical science. One example could be an assessment of treatment effects on sperm motility of an animal. The standard procedure involves taking film clips of sperm (or any other moving objects) through a microscope and measuring average linear velocity of particles on these film clips. The program used for measuring these linear velocities is important, and there are not too many choices to my knowledge. However, my knowledge might be limited.

I have previously used CellTrak for measuring sperm swimming speeds. The program works well, but lacks a batch processing function. As the assessment bases on a considerable number of replicates, I end up with 1000-2000 film clips to be analyzed and clicking my way through CellTrak is a tedious and irritating process. Also CellTrak licence costs a lot of money for such a poorly written program.

Therefore, my question is: Is someone aware of a similar program to CellTrak, which includes batch processing option, or even better, which works through command line and can be looped? Are there open source options or extensions to widely used open source programs (ImageJ, Bioconductor, etc.)? Please give a short tutorial/personal experience to the usage of the suggested program (if any).


texts: Why do almost all SNPs have two alleles?

texts:
Reading the Wikipedia page for SNPs I find the sentence "Almost all common SNPs have only two alleles." This is consistent with terminology elsewhere, such as the therm "Minor allele frequency", which references the least common allele, which implies there are generally only two alleles for a given SNP.

But there are 4 common nucleotides, A, T, C, and G. Why wouldn't it be common to have 3 or 4 alleles at a certain location? The only way this seems possible to me is if strand is ignored, and so at any given location "A" and "T" are considered the same allele and "C" and "G" are considered the same allele. Is this the case, or am I misunderstanding things.


texts: Why is the heart adversely impacted by chronic psychological stress, yet it benefits from routine physical exercise?

texts: Chronic psychological stress is commonly said to be deleterious to the heart, and predispose one to cardiovascular disease. Yet the opposite is said about regular aerobic exercise. Physiologically, What is the difference between psychological stress and physical exercise, with respect to their impacts on heart function/health? Both involve an increase in sympathetic cardiac input, and thus more vigorously contracting cardiac muscle; but how is one damaging and the other beneficial?


texts: Dolly the sheep was a clone. When she was born she was eight years old on her 1st day of birth, her mother (from which she was cloned) was also eight years old. What is a molecular reason behind this - that Dolly was eight years old when she was born?


texts: Why do specifically bananas go brown quicker in the fridge?

texts:
Perhaps the title should be: Why don't all fruits containing phenol residues go brown quickly when left in the fridge?

Bananas go brown over time because of the oxidation of phenol residues.

Bananas go brown quicker in the fridge than left at room temperature. This seems to contradict the first point since the reaction should be slower at colder temperatures. Dialogue from the naked scientists briefly explains why my line of thinking might be wrong.

  Emily: Well it’s a good question and the answer is that they will
  brown faster in the fridge.  It’s mainly due to the formation of ice
  crystals, so if you put your banana in the fridge, the ice crystals
  grow, and they actually rupture the cells of the banana skin. This
  releases an enzyme called polyphenol oxidase and as the name suggests
  it acts to oxygenate phenols, which have a ring-like structure, into
  quinones, and these quinones can then all join together or polymerise
  and produce a black, brown, or red pigment called polyphenol and this
  is what gives it the brown colour. So, if you have your banana in the
  fridge, this will occur and you'll get a brown banana.  But another
  interesting thing about bananas is that if you have them in the fruit
  bowl, they'll release ethene and this will make the other fruits in
  the bowl ripen faster because it’s a ripening hormone.

  Chris:   So, the question is though, if this is a chemical reaction
  making this brown pigment, if you slow down the reaction by lowering
  the temperature, then it should happen more slowly, therefore, going
  in the fridge should make the bananas go black slower?

  Emily:   I can see why you're thinking that but actually, it’s more
  the rupturing of the cells.  So if you have a banana on your table,
  the cells are going to be intact, the enzymes contained, and the
  reaction is not happening at all whereas if you put in the fridge, the
  enzyme is released and the reaction can happen – although yes, it
  might happen slower.

At the risk of channeling people into a yes or no answer, could someone clarify for me if the following statement is true maybe with a peer-reviewed source, which I've had no luck finding:

  TLDR Bananas go brown quickly in the fridge because cell lysis, caused by ice crystal formation at cold temperatures in the fridge, releases Polyphenol oxidase (PPO) into the surrounding area which freely causes more browning.

This leads me to another seeming paradox and the question I would like answered: Why doesn't this rapid browning in cool temperatures happen for other fruits and vegetables? What is special about bananas?


texts: How can diving with 100% oxygen not destroy your lungs?

texts:
It is possible this should be moved to physics, depending on the nature of the answer (i.e. if the reason is physical). But I suspect the explanation is biological, so I posted it here.

Sometimes technical divers dive with 100% oxygen. I don't understand how can this not burn, oxidize or at least damage their lungs. To begin with, even if someone would breath 100% oxygen in atmospheric pressure, I'd suppose he'd damage his lungs, because the 79% of the volume that would normally be filled with inert nitrogen is now filled with oxidizing oxygen.

If, however, someone dives to, say, 30 meters, with pure oxygen, he'd have to fill his lungs with oxygen at 4 atmospheres to equalize the pressures. That means the pure oxygen filling his lungs is even more concentrated. How can this be? A friend of mine who dived with pure oxygen even says the breathing feels just normal. How is this possible? How are the lungs not damaged?


texts: How did the endoplasmic reticulum come to be?

texts:
Organelles are sub-cellular compartments in cells. However prokaryotes don't use organelles to organise their intracellular space.

Evolutionarily, there is evidence that mitochondria and chloroplasts are ancestors of symbiotic prokaryotes. This theory is called the endosymbiotic theory.

I've tried to find an evolutionary story that explains other organelles, specifically the endoplasmic reticulum. There is plenty of literature about biogenesis of these organelles, but nothing about the history of their evolution. I don't think I have found the right area of literature. What did organelles originate from? I'm happy just to know a few keywords or a citation to look it up myself.


texts: How to generate simulated mass-spectrometry data for phosphorylated proteins?

texts:
I am trying to generate simulated MS data (Top-down and Bottom-up) for phosphorylated protein such as platelet-derived growth factor receptor (PDGFR-B). There are 10 tyrosine sites which are phosphorylated. Could you kindly tell me if there is any good software application to help me do that?

Also, how can I include in the input file (FASTA) that there are 10 modification sites on the protein sequence?

What are the parameters required to be set for top-down and bottom-up MS separately?


texts: Was the frequency of mutations more during primitive earth due to radioactivity?

texts: Primitive earth was more radioactive (or was it really?) according to radiometric analysis of C14 which suddenly appeared at 4250 million years in the Hadeon eon. Is it possible that ancient high levels of radioactivity could affect the mutation rate of early organisms? Does mutation frequency accelerate evolutionary process and/or speciation?


texts: Why is it sometimes difficult to resuspend E. coli in P1?

texts: It's a curiosity question. When I'm doing minipreps after pelleting the bacteria sometimes it's very easy to resuspend them in P1 (Qiagen kit), but sometimes they form a rubbery clump that is very hard to break up with a pipette and I have to vortex the tubes. It interests me because it adds more time to my lab work and I wish I could avoid it.


texts: Why does the butterfly have a cocoon stage in its life cycle? It could have simply grown up within the egg/cocoon, and emerged as a butterfly. Instead it is first an egg, then a worm, then a chrysalis, and finally after some time a butterfly.


texts: Do the organisms within a lichen communicate with each other?

texts:
So you've got your fungus and your algae (or cyanobacteria) (and the multitude of other variations and additions to this two-species symbiosis that lichens present). Do the species that comprise the lichen communicate with each other via chemical or electrical signalling? For instance, could an algal cell "tell" the fungus that it's diseased, thus triggering the allocation of more resources toward pathogen resistance?

And if there is no communication, how have lichens been so successful?


texts: What is meant by genomic imprinting being reversible?

texts:
I'm not trying to understand the underlying molecular processes, rather understand it conceptually.
This is what it says in my coursebook:

"The imprint, obtained during gametogenesis, is reversible: an allele
with paternal imprint will, after transmission through the female
germline, be changed into an allele with maternal imprint.
In other
words:
Paternal imprinting means that some gene obtained from your
father is 'silenced'. These 'silenced tags' remain during your whole
life, but are reset during the formation of egg-cells or sperm-cells.
Some genes are always silenced in egg-cells, others in sperm-cells.
There is a continuous activation and deactivation in function of the
parent who transmits the gene"

I don't understand how the first paragraph and the last paragraph can both be correct.
If the paternal imprint changes into a maternal imprint after passing through the germline, this implies that the gene is just deactivated in the chromosome that is passed on and we call is paternal or maternal depending on who passes it on.
On the other hand, the last paragraph (and the middle one) imply that, if you receive a gene with maternal imprint from your mother as a man, your body resets the 'silencing' during gametogenesis, realizes a sperm cell is being made and decides not to silence it since it will now be passed on from a father. Only this can explain why it would lead to continuous activation/deactivation or reversibility.
Which of the two is correct?


texts: How does a cell "know" the coding strand vs. the non-coding strand of DNA during transcription of mRNA?


texts:
It's possible that this is offtopic here; if so, please let me know.

I'm wondering what technologies exist that rely on evolution being a correct model; I'd like to be able to offer examples of that to people who find it to be "just a theory". As an example, I can point out lots of technologies for which our models of electromagnetism have to be correct to an immense accuracy for them to work - computers, any electrical wiring, electrical motors, light bulbs, electrical ovens, etc. etc.

The best I could find as examples of technologies that require our models of evolution to be fundamentally correct are things like pharmaceutics that work against germs that have developed a resistance against other pharmaceutics.

What are some good examples of technologies that require our models of evolution to be fundamentally correct for those technologies to work?


texts: What is the advantage of circular DNA in bacteria?

texts:
From what I understand, bacteria have circular DNA. What advantages does it have over linear strands like for eukaryotes?

Do there exist bacteria with more than one ring of DNA?


texts: Many plants (e.g. roses, palms) can be protected from frost during the winter if shielded with an appropriate coat that can be bought in garden shops. Do plants produce any heat that can be kept inside with these "clothes"?


texts: How do I look for pathogen in water with a microscope? Is it possible?

texts:
I am a 9th grade student from Manila and we're currently working on an investigatory project. We want to know how effective SODIS or solar water disinfection is. The purification method claims to be able to kill pathogen. We've just finished our methodology; we have not done to experiment yet.

There's one thing that concerns us: is it even possible to see pathogen in water using a microscope? We raised our concern to our teacher and at first she believes it is possible. However, she said that she was not sure because she mentioned that some stuff (I forgot what) are "cultured" before checking for pathogen like  bacteria.


texts: How the concentration of an antibiotic is chosen for YPD medium?

texts: I need to prepare YPD plates containing hygromycin, but I don't know which concentration I can use. I'll select transformants of Hansenula polymorpha.


texts: Could there be latent infections in the human population that we don't know of?

texts:
Herpes simplex 1 virus and toxoplasmosis are common infections that that many of use have (65% and 10% of americans, respectively). Both of these are chronic, latent infections that can occasionally cause problems (i.e. in HIV patients) but most of the time don't.

Could there by many other such common, latent infections in the human population that we don't know of? Do we have any idea of how many there would be?


texts: Which animal that lives in the forest makes this noise?

texts:
Which animal makes this noise? Link to audio file

The file was recorded next to a forest in Germany.


texts:
It is commonly proposed to look for life based on silicon, based on it's relative abundance and similarity to carbon. However, carbon and silicon are not completely interchangeable. The bond strength between carbon or silicon and itself is different, thus, some molecules with high chain length can not be replicated with silicone. Similarely, molecules such as proteins, for which all carbon atoms are replaced with silicon, would not retain their form and thus not their function.

Is life based on silicone still possible, just under a different environment?

This would affect how we should look for aliens. Also, if silicon based life is unlikely, is there some other element that could lead to life?


texts:
"Mesothorax length (the distance from the tip of the scutellum to the
  most anterior part of the mesothorax)"

From Bergland et al 2008.

Would that be this distance (green line)?

If not, how would you describe that distance?


texts: Does the lack of "mirror life" tell us anything about abiogenesis?

texts:
My (extremely rudimentary) understanding of Biology is that many of the building blocks of life are chiral and that life on earth is entirely made up molecules with the same chirality.

Does this have any interesting repercussions for our understanding of abiogenesis?

EDIT:
Just to be clear I am interested in understanding how life developed from non-life (on Earth in particular and, more speculatively, in the universe broadly). For instance, the article linked in Matt's answer that it may be due to the polarization of light in our area of the galaxy is very interesting.

I see several (not necessarily exclusive) hypotheses (and probably am certainly missing some) about the asymmetry of the chirality of existing lifeforms of and was wondering if there was any sort of consensus (or at least informed speculation) on which was more likely or less.

Abiogenesis is an incredibly rare phenomena and so the opposite chiral life never developed.
Which every chiral form of life appeared first and this prevented the formation of the other chiral form of life.
There is some sort of selection principle that selects for the chirality we appear.
If simple versions of life and mirror life occur simultaneously it precludes or retards the development of complex lifeforms (A sort of anthropic principle).
``Mirror life" is not actually possible--there is some subtle phenomena that requires the chirality we have on Earth.
Something else...


texts: Transmission of epigenetic regulation through surrogate mother

texts:
I know the basics of epigenetics, but I do not know how epigenetic mechanisms are transmitted from parents to children (or if there is even enough literature to derive a consensus). My question is relates to surrogate motherhood, in which an egg is fertilized in vitro and then implanted in the womb of a woman other than the egg donor.

Are all the factors that affect epigenetic mechanisms encoded in the genome? Is it possible for the surrogate mother's epigenetics to influence the epigenetics of the child/children?


texts: Are mutations a source of genetic variation?

texts:
Here is a question from the book SAT II Success Biology E/M (where the SAT is the exam taken by the American high school students):

  Which of the following statements is true about mutations?
  (A) Rates
  tend to be very high in most populations.
  (B) generally lethal
  (C)
  irreversible
  (D) Only certain gene locations are affected.
  (E) source
  of genetic variation

In my opinion, we can definitely eliminate A, B, and D.
Then, I struggle between C and E since I think mutations are definitely a source of genetic variation but are as well generally irreversible (I've found evidence on different websites, including this http://hawaiireedlab.com/wpress/?p=154 where the author writes that only some mutations are reversible).
In the end, I think I should have probably gone with E because C can be seen as having some exceptions.
Then, here is the book explanation for this question:

  The correct answer is (C). These recent conclusions about
  mutations—recall that Darwin did not know of mutations—are all the
  reverse of those listed in the choices, with the exception of choice
  (C), the correct answer. Rates, in fact, tend to be below in
  populations, mutations are generally not lethal, any gene location can
  be affected, and they are felt to be the source of genetic variation.
  Darwin felt over-production of offspring was the source of potential
  variation.

The answer is C here. However, I didn't particularly understand why E wasn't considered a correct answer.
Could you please explain why C, and not E, is correct?


texts:
I've been farming freshwater fishes. After some time, i found some green algae grows there. When the algae dried, it looks like nori (which commonly used for sushi wrapping).

So, i wonder if those algae edible for human. Are the algae safe to eat?

Here's the picture:


texts: Identification of Jumping Spider Species

texts: I found this jumping spider (Salticidae family) in Pune/India. Most common species of jumpers in my region is heavy-bodied jumper (Hyllus semicupreus), but this is different species by observing body size and blue colored patch under eyes. Its size was about 7mm-8mm.


texts:
I have a supplement for use in horticulture.  It is a powder that contains mostly subtilis with smaller amounts of a few other strains.

Prior to horticultural application I would like to "multiply" them so as to get to most out of the product.

Is water and a drop of molasses sufficient? (that seems to be accepted in cannabis culture)

How fast do these guys replicate? Without high tech lab equipment is there anyway I can tell that they are in fact multiplying?


texts: does Trichloroacetic acid remove fats from milk

texts: I am trying to detect melamine in milk. As a part of preprocessing, I add 200 ul of TCA to 1 mL milk,and after filtration I get a clear solution. Does the filtrate contain fat. I feel I am having interference from fat even after extraction.


texts: To what extent can humans, (mammals in general), theoretically regenerate, and is their a way to speed up and/or exceed this original extent.


texts: Does anyone know the optimum length of overlap your primers should have to your vector for gibson assembly. Most manufacturers say to do at least 20 bp on both side but don't give a maximum. Sometimes I add 30-35 bp on both I don't know if that hinders efficiency.


texts: most different human tissues with respect to gene expression profiling

texts:
Is there a PCA showing the relative distance in terms of gene expression / functional genomics among the different human tissue types?

So far I have found:

(1) A paper based on gene expression with some tissues/tissue groups, not many:
https://genomebiology.biomedcentral.com/articles/10.1186/gb-2010-11-12-r124

(2) A paper based on gene expression signatures and aging:
https://www.nature.com/articles/npjamd201614/figures/1

(3) A paper on Gene and Protein Expression in Normal and Cancer Tissues:
https://www.nature.com/articles/srep24799/figures/3


texts: If an insect becomes upside down, do they have mechanisms to turn themselves right side up?

texts:
This question is mainly applicable to beetle's and cockroaches. If I flip them so their legs point upward, they usually squirm around and wiggle trying to come back upright. Sometimes they succeed, and turn right side up again; sometimes they don't. Do insects have any built in mechanisms to unflip themselves.

I was unable to find any sources, but I believe they should, since insects climb stuff, and they may land inverted if they fall, so a mechanism might've been evolved to unflip themselves.


texts: How early can we know the sex of a human being now?


texts: Does natural selection apply to entire populations as it does to individual organisms?

texts:
The context: the other day I was reading an article about a peculiar species of ant that when threatened by a predator would “explode” in order to help protect the rest of the colony, although it kills the individual ant. I was wondering how this kind of behavior could evolve via natural selection if it only picks out the individual organisms best suited for the environment - because it seems like a self-destruct type of behavior wouldn’t be helpful to the ants that are trying to survive and reproduce. Though it would make sense if natural selection also applies to entire populations as it does to individual organisms - picking out entire populations that are best suited for the environment. It would make sense because populations that have individuals willing to explode to help protect the other individuals would have an advantage over the ones that don’t.

The question: does natural selection apply to entire populations as it does to individual organisms or have I made a mistake somewhere in my logic - and if so, where?


texts: Why should evolution not be equated with progress?

texts:
My science textbook says this:

  Evolution should not be equated with progress. In fact, there is no real 'progress' in the idea of evolution. Evolution is simply the generation of diversity and the shaping of the diversity by environmental factors. The only progressive trend in evolution seems to be that more and more complex body designs have emerged over time. However, again it is not as if older designs are inefficient! So many of the older and simpler designs still survive [..] In other words, human beings are not the pinnacle of evolution, but simply yet another species in the teeming spectrum of life.

I am not sure if I agree with this; after all, humans do seem to be more advanced than dogs. Many people have asked me why I thought this was true, so here is my answer: Today, humans could wipe out dogs from Earth if they wanted, but you can hardly imagine  a scenario in which dogs would do the same to humans.

What am I missing here?


texts: Dataset of microscopic images before and after staining?

texts: I am looking for a freely distributed dataset of microscopic images. I am hoping to find a dataset that would feature histological images before and after staining (e.g. H&E or some other standard one, preferably). I have been searching through various databases, but I cannot find a proper set. I hope the sample size to be at least about 100. Suggestions?


texts:
a) An Enucleated ovum
b) Mature RBC
c) A mature spermatozoan
d) Hair root

According to me, there can be 2 answers, a and b because an ovum whose nucleus has been removed lacks DNA. And also, initially RBC has a nucleus but as it matures it's nucleus disappears. So, mature RBC should also lack DNA. Then which one will be a more appropriate answer ?


texts: Why is a mosquito feeding on human blood not a parasite?

texts: I recently read in my Ecology course notes that a mosquito feeding on human blood is not considered as a parasite. However, since it sucks blood from the human body, shouldn't it be regarded as a parasite, just like lice and ticks?


texts: Are there emotions that motivate pattern completion? If so, where in the brain are they located?

texts:
I have been studying musical "tension." Musical tension essentially refers to the "expectations" one builds up in a melody that are then "released" when a stimulus matching the expectation occurs. For example, if you play the white notes on a piano in order CDEFGAB, you have a "tension" that motivates you to finish the scale and play C to complete the pattern.

I am aware pattern completion occurs in the brain and have seen a few biological models of this. For example, with attractor network models of human memory. So I am not surprised obviously that pattern completion occurs. But this example with musical tension highlights how there is an emotion (aka drive or motivation) that compels me to complete the pattern. When I hear the sequence CDEFGAB, I am compelled to finish the sequence.

My Question

Can someone provide me of examples of canonical models of emotions influence on pattern completion? I would like to learn example mechanisms as to how, on a circuit level, emotion would influence pattern completion.  I am particularly interested in examples relating to common forms of human creativity like visual art, problem-solving, etc., but any examples will do.


texts: Is post-transcriptional regulation of gene expression an epigenetic process?

texts:
Is post-transcriptional regulation of gene expression (for example regulation by microRNAs) a type of epigenetic gene expression regulation?

I think we can categorize it as epigenetic since the DNA sequence is not changed, but I have never come across that terming in any papers. Does someone have any idea, or know of any papers that categorize post-transcriptional regulation as epigenetic?


texts: Majority of transcripts are from sense strand?

texts: I am wondering whether majority of transcripts are transcribed from the 5'->3' strand? Because I encounter a lot of expressions like "anti-sense transcripts". Could anybody help clarify this? Thanks.


texts: Do spouses begin to share genes over time?

texts:
I apologize if this hypothesis sounds strange by I was wondering if any research had been done on a phenomenon which I've seen and have corroborated with many other - the idea that over time spouses tend to start looking similar to each other.

My hypothesis is that this is really a one-way street with the wife tending to look more like the husband. The reason being that after coitus her body is flooded with his genetic material which may lead to some mixing of DNA outside of the egg. Furthermore once the woman is pregnant she enter into a symbiotic relationship with an organism whose DNA is approximately 50% foreign. Her body must then adapt to the presence of that new genetic material.

I realize this may sound strange and Lamarkian but I was curious if the phenomenon itself had been investigated.


texts: Identify this large exotic bird spotted in Taipei, Taiwan

texts:
A few months ago while backpacking in Taipei I found this very intriguing large bird facing off a curious puppy in a fairly busy pedestrian area.

The bird did not attempt to fly. None of the Taiwanese locals could tell me what it was and attempts to Google it via description all failed.

I'd appreciate learning the species name, common name in English, and/or common name in Chinese:


texts: How can we create a living dinosaur using DNA technology?

texts:
I'm wondering what would we need to do to create a living dinosaur using DNA technology? If it is not possible with current technology, will it ever be feasible?

In the movie Jurassic Park, scientists extract dinosaur DNA from a mosquito which was preserved in amber, and which has sucked blood from a dinosaur. The DNA is incomplete, so the scientists splice it with frog DNA. The DNA is then inserted into a crocodile ova and an embryo is created, and so on.

The Jurrassic park method is dubious. Although dinosaur DNA has been found and isolated, it was too damaged to restore it to its original form using current technology. It's not clear that splicing with frog DNA would work. Let's for the moment forget about how you would get the dinosaur embryo to develop and the eggs to incubate and hatch. I want to know how would we fully sequence the genome of some dinosaur?


texts: I am analysing RPE-1 cells from humans and I do not understand why I see so many kinetochores by immunofluorescence (more than 100 in many cells). They are in prometaphase.


texts: Should I dilute DNA with water or elution buffer?

texts: I've extracted DNA using a kit and final step is eluted with buffer. If I must dilute my DNA samples, do I use the same elution buffer or can I use milliq water?


texts:
What is the significance of running an uncut plasmid on electrophoresis gel?
In this case we are talking about inserting a gene into plasmid, which then goes under PCR and then electrophoresis.


texts: Is "Cisternal Twins" an actual classification of twin types and if so, describe it

texts:
I always assumed my brother and I were identical twins. Now my mother, in her eighties, says we are cisternal twins, but I cannot find any references on the matter. Is there such a thing? If so, what traits make them so?

appended: also, we've been called mirror twins. In a study by a student, we learned that our fingerprints are nearly exact opposites.


texts: Ancient DNA of ancestors or existing species?

texts:
Ancient DNA appears to be at most "several hundred thousand years" old.

Do we have an aDNA sample which we can reasonably confidently attribute to a species which has at least two modern descendants?

PS. This question is much less interesting than I originally thought: there are modern species which are proven ancestors of other multiple modern species (lake Victoria Cichlids).


texts:
I read this article: http://www.sciencedaily.com/releases/2006/09/060926171045.htm

It says, "When people are made to think quickly, they report feeling happier as a result. They also say they are more energetic, more creative, more powerful, and more self-assured. In short, they reported a whole set of experiences associated with being "manic."

"The results of our experiment suggest the intriguing possibility that even during moments when people feel stuck having depressed thoughts, interventions that accelerate the speed of such thoughts may serve to boost feelings of positive affect and energy."

Is there any biological basis for these claims or could the results be self-reporting biasness?


texts: How does a thymidine block halt DNA synthesis?

texts: The best I've been able to find is that there's a feedback mechanism, but what is this feedback, and how does the mechanism work? If it's just that the concentration of thymidine is too high, why won't excess quantities of other nucleotides do the same thing? (Or do they, and I don't know about it?)


texts: When fish started developing the stronger limbs needed to walk(Slither?) onto land how was this beneficial? I cannot think of any form of food that would be helpful that would not be plentiful in water, but it must have been so as from what I can tell most beneficial mutations tend to be either a better way to either survive or obtain nutrients.


texts: Are there public records of results with laetrile treatment against cancer?

texts: I'm looking for what the title says. This is based on the book by Edward Griffins. Is laetrile actually fatal because of its cyanide content? Or can it really help in this fight?


texts: How are Stem Cells Produced for Stem Cell Based Therapies?

texts: I was doing an initial search on google but couldn't come up with anything I'm looking for. I know were stem cells come from and a bit about their levels of differentiation. For example, embryonic stem still becoming mesenchymal stem cells and what not. I also understand that epithelial tissue cells can be converted to a pluripotent stem cell state but at very low efficiency. So, all that aside how are stem cells obtained in the volumes necessary for stem cell based therapies without causing them to start differentiating during production?


texts: If your atlas is out of alignment, will the rest of your spine be out as well?

texts:
I just found out about this association called Nucca. Basically, they are a chiropractic association - their whole idea is that if your atlas is out of alignment, then the rest of your spine is also out of alignment, because your atlas controls it all. Also, the nerves will get pinched and therefore cause pain.

Is this legit?


texts: What is the name of this insect? Is it venomous or possess any threat to human life if someone gets stung?

texts:
I found it in Northern part of India, on a mango tree. When I intended to move it away from home, it seems to bite like a snake with front part lifting like a king cobra.

This insect is 6-7 inches long, 1-2 inches wide, and appeared during summers.


texts:
Can anyone explain the mechanism of hydrotropism and what kind of plant hormone involved?
Our teacher says that it hasn't been proven yet. I looked up many data only to find about the phenomenon of this effect.


texts: Is Plasmablast a precursor of Plasma cell?

texts:
I read it in Roitt's Essential Immunology.

  Plasmablasts are precursor cells of short- and long-lived plasma cells and
  are generally described as a proliferating fraction of
  antibody-secreting cells, often found in the bloodstream
  emigrating to organs such as the bone marrow.

I coudn't find any authentic source repeating the same.

Is it true? Is this book authentic enough to follow?


texts: Differences between Gradualism and Uniformitarianism

texts:
From what I understand, gradualism is the idea that small changes affect species over time. Uniformitarianism argues that the same processes that occurred in the past are the same as those in the present.

Does gradualism state that these small changes are constant over time? In that case, it isn't much different from uniformitarianism.

I'm thinking that the difference that uniformitarianism allows for catastrophes and supports Aristotle's scala naturae, while gradualism makes a point for evolution due to its theory of slow processes.


texts: Optimization of E. coli growth in D₂O (heavy water)

texts:
I would like to find a method of increasing the biomass of my D2O cultures because my current method is not yielding enough protein. I would like to also minimize the amount of H2O in my culture.

My current methodology is a small scale growth of 3mL with 75% D2O and LB grown for approximately 9hrs. This culture is then used to seed a 20mL 100% D2O and M9 culture overnight and this entire culture is used to seed a 1L D2O and M9 culture.

Thanks for your time.


texts: Can a viable embryo develop from the fusion of two egg cells?

texts:
For a zygote to form, two haploid gametes undergo meiosis and fuse during fertilisation. Since two egg cells (or even two sperm cells) are both haploid, is it theoretically possible for them to make an embryo (via experimental manipulation)?
I’m guessing that if such a thing were possible, the two egg cells could each come from the same organism or two different sources.
Would there be any side effects, such as persistence of mutant alleles due to a lack of genetic variation if both egg cells originate from the same organism?


texts: Why do some vaccines lose their efficacy with time?

texts:
Why do some vaccines lose with time their efficacy?
The two obvious examples that I have in mind are influenza and tetanus. The former case is clear, as influenza virus undergoes frequent gene reshuffling with similar viruses, which renders the vaccine inefficient against what can be essentially considered a new virus. So the question is about tetanus: does it have to do with the fact that it is bacterial rather than a viral effection? Why the immunity is lost? Are there other similar cases?


texts: What is the response vector in the fMRI GLM model?

texts: In fMRI, univariate analysis typically makes use of the general linear model (GLM), where the relation between experimental condition and BOLD activity is estimated with a linear regression model for each voxel separately ("mass univariate model"). However, I found it surprisingly hard to find out what the response vector $Y$ contains. I am aware that it is some measure of the blood oxygenation level dependent signal (BOLD signal) - but what is measured exactly, i.e. what are the units? Is it the oxy/deoxy ratio, or is it another property?


texts:
At some point between 2002 and 2006 I attended a departmental seminar in the UK on Vibrio infections, and particularly on the (then relatively unheard of) V. vulnificus, which causes necrotizing wound infections and septicemia when it enters open wounds. The speaker discussed two case studies: the first was of a case (possibly a cluster of cases) in a garage, I think in Australia, where the workers repeatedly topped up a liquid soap dispenser from a big bottle rather than replacing the bottle, and it had at some point become contaminated with V. vulnificus, which had survived in the soap, and infected an individual who went to wash their hands because they cut themselves.

The second case, which I only mention because it was part of the same talk and I have a suspicion the seminar speaker (whose name I can't remember) might have written papers on both, was about the rise in V. vulnificus cases in the Middle East (Israel, I think) which arose from a new trend for fish markets offering live fish in tanks at market rather than transporting them for a few hours on ice before sale (which was previously killing the bacteria, which occurred fairly ubiquitously in Israeli fish farms due to the high water table and high groundwater salinity).

This was a great seminar with two great stories that illustrate the ecology of Vibrios and I'd love to have sources for either, but particularly the first one. However, I can find no mention of either in the literature. Can anyone help?


texts: Why is there no symmetry in pigmentation when comparing people north and south of the equator?

texts: If you are at the equator and start moving north, the further you travel, the lighter the skin of the indigenous peoples. Considering that we live on a ball, why do we not find the same traveling south from the equator? This relationship does not hold for individuals as you move south from the equator.  At the very least, one could say there are no blond hair blue eyed peoples south of the equator.


texts: This skull was found in the mountains/woods of extreme southwestern Virginia (Dickenson County). There is not (to my limited knowledge) any animal native to this area that has this type of skull. Anyone have any idea what it could be? Sorry, no teeth or lower jaw were found. The backbone seems to come directly out from the back of the skull and the nose/beak/front area seems to be flared on the sides.


texts:
This bee visits our balcony every day multiple times, but only for a brief time, making it hard to take a good picture:

Here's another picture, I finally got lucky so I'm adding it to the question:

It does not look like a typical honeybee. It does not make noise as bumblebees do. It also looks a lot like it's really the same creature every day. It always comes and leaves on the exact same path. The face looks a lot like carpenter bee, but I also couldn't find one like this on the internet.
This is in central Europe.


texts:
This article about testing for Alzheimer's, via changes in the ability to smell, said:

  She thought of peanut butter because, she said, it is a “pure odorant”
  that is only detected by the olfactory nerve and is easy to access.

I'm not clear on what that means. Assuming a person had their mouth closed, then wouldn't any odor be detected only by the olfactory nerve? Wouldn't a lemon, say, work exactly the same?


texts: Survival of streptococcus after my scarlet fever

texts: I'm currently sick because of scarlet fever but I got treated with antibiotics. I know that after 1.5 day using antibiotics the streptococci I release at home are dangerous anymore. But my question is, what about the streptococci I've spread before? I've read that Streptococcus pyogenes can survive 3 days to 6.5 months outside the host, does that mean, I have to disinfect the whole house? And if so, with what should I desinfect? I worked heavily on the laptop, how do I desinfect that? Thank you.


texts: Does the genetic material the sperm carries affect its physical properties

texts:
Basically, what I'm asking is, is the actual sperm cell built from the blueprint in the DNA of the man or is it itself also a consequence of the DNA it carries?

I'd like to know a few more things related to this. For example, which DNA is in the nucleus of a sperm? Is it the same as the DNA of other bodily cells in the man's body, or is it just the DNA it's delivering? Can the sperm's performance be affected by any specific genetic traits that can be observed in a potential human the sperm could make? For example, a sperm swims faster if it's carrying the genetic material that would result in a tall person (probably a silly question).

The original question I had is if the statement that female sperm live longer is true. If it turns out that the man's body makes all the sperm more or less the same and they're just boxes that can swim, then I would guess the answer is no.


texts: Why is it that heterozygous loci appear as two separate bands during gel electrophoresis while homozygous loci appear as one band?

texts: Is it because heterozygotes have a greater base pair length? (And if they do, why is that?) Or is it because recessive alleles are moving slower than the dominant alleles in the gel?


texts:
I am not a biologist and I would love to understand what is going on with this pathway.
I went to the description but it's still complicated, and I couldn't follow. Can someone please help me with it? Is this a comprehensive pathway or is it based on specific details? How do i read this pathway?


texts: Can anyone identify this spider for me, please?

texts: I live in Northern Indiana and I’ve seen 3 of these spiders in my house before, all different ones. When I first saw it, it scared me since it’s a pretty big spider in my opinion from what I usually have seen around here. This spider was bigger than a quarter all together. I know it’s not the best picture, but this is it on the wall a while ago. Also was a very fast spider so I couldn’t capture it too well. Are they harmless? I woke up with a bite today and then I remembered this!


texts: Does science have an explanation of how the first "common ancestor" formed in evolution?

texts: I always have this question on my mind and I need a better explanation on this. Does Charles Darwin's theory explain it or are there any other theories which explain it better than Charles Darwin's theory?


texts: Has a beneficial mutation ever been documented?

texts:
I am trying to find a case/study where scientists documented a mutation in an animal or human that was to the benefit of the host.

The closest thing I have been able to find is sickle cell anemia (SCA) helping to fight malaria. However, the life expectancy for people with SCA is 40 – 60 years, and in 1973 it was only 14 years (source). I am looking for another case, preferably one that is not life-threatening.

Are there any other cases where a beneficial mutation — one where the good outweighs the bad — was documented?

By beneficial I simply mean that it helps or protects the host in some way, while not causing substantial harm. As in my example of SCA it can benefit the host if the host lives in an area with malaria. However, it is also life threatening and reduces the life expectancy of the host.

If — for example — SCA would only cause pain and not be life-threatening, then it would (in my opinion) be a beneficial mutation. While not purely beneficial, it would still increase the life expectancy of people living in an area with a high occurrence of malaria.


texts:
I'm writing up a report and I see conflicts everywhere on the internet. Should it be Murine Minute Virus (MMV) or Minute Virus of Mice (MVM).

The followup question is does it really matter.


texts:
This is something that I have heard/read so many different contradictory claims about over the years.

In high school I was taught that sperm cells have a lot of mitochondria because they need a lot of energy quickly. This made sense to my adolescent mind.

When I was an undergrad, my one microbiology lecturer swore up, down and sideways that they did not have mitochondria. She never gave any reason or evidence, but I had gotten used to the idea that high school info was often out of date and, sometimes, completely incorrect, so I let it slide.

Then I was reading an article for a paper several years back and it said that, not only did sperm cells have mitochondria, but they did not lose them all. That in fact, some were preserved and engaged in genetic recombination with the mitochondria belonging to the ovum (the maternal ones). This contradicts another rule that so many treat as certain, which is that while nuclear DNA is 50% from each parent, mitochondrial DNA is exclusively maternal.

To sum up: Do spermatozoa contain mitochondria or not? And if so, is the recombination I described above likely?


texts: What Goes on in Photosystems at the Molecular/Atomic Level?

texts: In light-harvesting complexes, how is the energy of a photon transferred from one pigment molecule to another? And in reaction-center complexes, how does the primary electron acceptor capture an electron from the chlorophyll a? It’d be best if any of you could explain this to me in terms of what’s happening at the molecular or atomic level, say with electrons.


texts:
I am currently on the lookout for Trypsin, but I have some trouble finding something that is fairly cheap, ships to Europe and is equivalent to this Trypsin:

http://www.emsdiasum.com/microscopy/products/chemicals/tannic.aspx#22200
Trypsin powder 1:100 from Porcine Pancreas, 25g
Activity >100 NF units/mg
Used for whole cell preparation

I've found Trypsin on Sigma:

http://www.sigmaaldrich.com/catalog/product/sigma/t4799
Trypsin powder from Porcine Pancreas
Activity 1,000-2,000 BAEE units/mg
Suitable for cell culture

However I am not sure how to compare the activity between the two types and ultimately which concentration I should then use in my experiment if I go with the Sigma one (the protocol I am following uses the EMS Trypsin in a 1g:100ml fashion).
Can anyone shed some light on this? Or perhaps show me the way to some affordable Trypsin that can be shipped to Scandinavia?

Cheers!
/Patricia

*The trypsin will be used for diaphonization (see comment)


texts: mitochondria has more activity or the numbers of them are more?

texts: If a cell is needing energy more than the other cells, does it mean that it has more mitochondria or the activity of them is more?


texts:
A 62 year-old male was admitted to the hospital complaining of shortness of breath. His chest X-ray showed a rightsided cavitary lesions. His medical history indicated he had smoked one pack of cigarettes per day for past 40 years and has had cavitary tuberculosis in about 20 years ago. Recently he is receiving cytostatic therapy for his acute myeloblastic leukaemia. A biopsy specimen of the lung was obtained. Biopsy from lesion shows tubular eukaryotic septated hyphae with diameter of 510 μm that are infiltrating the lung tissue. Culture on Saboraud’ media shows conidia with spores in radiating columns. Which is the most like cause of the findings?

The disease is systemic - affecting lungs.
Organism has septated hyphae with conidia.
Is there any other possibilities for the disease?


texts:
It is autumn out there. Green, brown, red, yellow, and mixed-colored leaves drop from the trees to the ground. What determines the colors of the leaves?

Wikipedia tells me

  Leaf senescence is the cause of autumn leaf color in deciduous trees.

Ok. What does the color code? If a leaf is red, why is it red and not yellow or brown or green or mixed-colored?


texts: Can someone tell me which spider this is please? I've found a few of them in my home in North-London, are they poisonous?


texts: Alcohol consumption and central nervous system

texts:
After alcohol intake, the cerebrum related functions like vision and speech is affected first and later on there's problem with the cerebellar functions like balancing and hand-eye coordination.
My question is- why is it so? Why do they appear in that order?
Like does it have anything to do with differential rate of absorption in cells, or anything else like related to anatomy rather than physiology.


texts: Fastest observed biologically evolution rate?

texts:
Fastest possible evolution rate?

What is the theoretically quickest evolution rate?

For example, I could calculate this as the number of offspring an E. coli colony can generate at once * (time frame/time per generation) * mutations per generation, and then assume every organism on earth had this same evolution rate.

Is there a generally accepted value, perhaps based on mass of organism?


texts: I live in Chapel Hill, North Carolina, and recently started seeing a bunch of these little guys in my house. They're about 1/8" long (estimate), with brown/black zigzag stripes; it's possible they're babies, but over the last two weeks their size has remained consistent so this seems unlikely.


texts: What is an aromatic cage and what does it do?

texts:
Epigenetics, 2. ed, Chapter 3.6:

  Similarly, methylated lysine residues embedded in histone tails can be
  read by “aromatic cages” present in chromodomains, or similar domains
  (e.g., MBT, Tudor) contained within complexes that facilitate
  downstream chromatin modulating events (see Ch. 7 [Patel 2014] for
  structural insights

I understand it is something like a protein motif, but I cannot find a good definition using google.


texts: Why are adults so suceptible to dizziness?

texts:
I have a child and she, like pretty much all the others it seems, loves spinny rides in the park. Adults often can't stand them.

In fact, I recall going from loving to hating dizziness over the space of about 3 years, at about the beginning of puberty.

Why do adults react more badly to dizziness than children?


texts:
As far as I've learned about T1D, the prevalence of the disease and autoimmune disorders in general over the past 5 decades intrigued me to the point it made me wonder if it's really a genetic predisposition. I've read that it could be related to a virus but as far as I've read and came to conclude, could it be the EBV virus in the first place as a primary suspect infecting the beta cells in those with no genetic hisory of diabetes in their families?

I learned that EBV infects the human body then morphs itself into a human cell look-alike, could it be why the immune system attacks beta-cells if EBV infected them?
I also learned that there is a significant population with islets' antibodies present in serum yet over the years they never develop T1D and they stay within perfect glycemic control.

My question is, were there any studies done to examine that EBV possibility being the cause of T1D and if there were any studies done to explain why some of those with islets antibodies never go through the T1D autoimmune storm?