{'fraction_non_alphanumeric': 0.016122531237404272, 'fraction_numerical': 0.0032245062474808546, 'mean_word_length': 5.41343669250646, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Identification of a Microsporidia Protein Potentially Involved in Spore Adherence to Host Cells

MICROSPORIDIA are obligate intracellular opportunistic protists that infect a wide variety of animals including humans and are the causative agent of severe disease seen in some immunosuppressed patients. Microsporidia spores are common in the environment and are often ingested with contaminated water. Host cell infection occurs by the forceful eversion of a coiled hollow polar filament from within the spore through the host cell plasma membrane. The contents of the spore are injected into the host cell cytoplasm where, following division and maturation, new spores are released to infect nearby cells or excreted from the host’s body. The mechanism of spore activation leading to host cell infection is unknown. However, it is logical that microsporidia may use a mechanism to achieve target cell proximity to increase the likelihood of successful infection. We believe that spore adherence to host cells may play a vital role in this process. Our previous studies have shown that sulfated glycans such as glycosaminoglycans (GAGs) on the surface of the host cell are important in spore adherence (Hayman, Southern, and Nash 2005). When exogenous GAGs are added in a spore adherence assay the percentage of adherent spores decreases significantly compared with control samples suggesting that host cell GAGs are receptors for spores. These data were confirmed by using host cells either deficient in surface GAGs or treated with compounds to limit the expression of surface GAGs. Importantly, when spores are inhibited from adherence, host cell infection also decreases indicating a direct relationship between adherence and infection. In an associated study, we showed that the addition of certain divalent cation salts such as magnesium or manganese chloride significantly augmented spore adherence to host cells above control levels (Southern, Jolly, and Hayman 2006). Similarly, when spore adherence is augmented, host cell infection also increases confirming our early assertion that spore adherence is linked to infection. Together, these studies substantiate the direct relation between adherence and infection and shape our current hypothesis that spore adherence is an integral process of host cell infection. In the current study, we examine a putative spore ligand, microsporidia adherence protein (MsAP), which appears to be involved in the spore adherence process.