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Articles by J Arredondo
Total Records ( 2 ) for J Arredondo
  F Diaz Fleischer , J Arredondo and M. Aluja
  Francisco Diaz-Fleischer, Jose Arredondo, and Martin Aluja

Early adult experiences in enriched environments favours animal brain and behavioural development ultimately resulting in an increased fitness. However, measuring the effect of environmental enrichment in animal behaviour in nature is often a complicated task, considering the complexity of the natural environment. We expanded previous studies to evaluate how early experience in an enriched environment affects copulation behaviour when animals are confronted with a complex semi-natural environment. Anastrepha ludens flies are an ideal model system for studying these effects because their natural habitats differ significantly from the cage environments in which these flies are reared for biological control purposes. For example, in the field, males form leks of up to six individuals. Each male defends a territory represented by a tree leaf whereas in rearing cages, territories are completely reduced because of the high population density. In a series of three experiments, we observed that male density represented the most influential stimulus for A. ludens male copulation success. Males that experienced lower densities in early...

  A. I Chernyavsky , J Arredondo , V Galitovskiy , J Qian and S. A. Grando

SLURP-1 (secreted mammalian Ly-6/urokinase plasminogen activator receptor-related protein-1) is a novel auto/paracrine cholinergic peptide that can bind to 7-nicotinic acetylcholine receptor (nAChR), a high Ca2+-permeable ion channel coupled to regulation of nuclear factor-B (NF-B) expression. Elucidation of intracellular signaling events elicited by SLURP-1 is crucial for understanding the molecular mechanism of functioning of this novel hormone-like peptide that alters vital cell functions and can protect from tumorigenic transformation. In this study, we sought to dissect out the role of 7-nAChR in mediating the biologic effects of recombinant SLURP-1 on the immortalized line of human oral keratinocytes Het-1A. A multifold upregulation of the NF-B expression at the mRNA and protein levels by SLURP-1 was only slightly diminished due to elimination of Na+, whereas in Ca2+-free medium the effect of SLURP-1 was inhibited by >50%. Both in the absence of extracellular Ca2+ and in the presence of Cd2+ or Zn2+, the SLURP-1-dependent elevation of NF-B was almost completely blocked by inhibiting MEK1 activity. Downstream of 7-nAChR, the SLURP-1 signaling coupled to upregulation of NF-B also involved Jak2 as well as Ca2+/calmodulin-dependent kinase II (CaMKII) and protein kinase C (PKC), whose inhibition significantly (P < 0.05) reduced the SLURP-1-induced upregulation of NF-B. The obtained results indicated that activation of 7-nAChR by SLURP-1 leads to upregulation of the NF-B gene expression due to activation of the Raf-1/MEK1/ERK1/2 cascade that proceeds via two complementary signaling pathways. One is mediated by the Ca2+-entry dependent CaMKII/PKC activation and another one by Ca2+-independent involvement of Jak2. Thus, there exists a previously not appreciated network of noncanonical auto/paracrine ligands of nAChR of the Ly-6 protein family, which merits further investigations.

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