Effects of Host Species Identity and Diet on the Biodiversity of the Microbiota in Puerto Rican Bats.

Microbiota perform vital functions for their mammalian hosts, making them potential drivers of host evolution. Understanding effects of environmental factors and host characteristics on the composition and biodiversity of the microbiota may provide novel insights into the origin and maintenance of these symbiotic relationships. Our goals were to (1) characterize biodiversity of oral and rectal microbiota in bats from Puerto Rico; and (2) determine the effects of geographic location and host characteristics on that biodiversity. We collected bats and their microbiota from three sites, and used four metrics (species richness, Shannon diversity, Camargo evenness, Berger-Parker dominance) to characterize biodiversity. We quantified the relative importance of site, host sex, host species-identity, and host foraging-guild on biodiversity of the microbiota. Microbe biodiversity was highly variable among conspecifics. Geographical location exhibited consistent effects, whereas host sex did not. Within each host guild, host species exhibited consistent differences in biodiversity of oral microbiota and of rectal microbiota. Oral microbe biodiversity was indistinguishable between guilds, whereas rectal microbe biodiversity was significantly greater in carnivores than in herbivores. The high intraspecific and spatial variation in microbe biodiversity necessitate a relatively large number of samples to statistically isolate the effects of environmental or host characteristics on the microbiota. Species-specific biodiversity of oral microbiota suggests these communities are structured by direct interactions with the host immune system via epithelial receptors. In contrast, the number of microbial taxa that a host gut supports may be driven by host diet-diversity or composition.

Association between recurrent aphthous stomatitis and inheritance of a single-nucleotide polymorphism of the NOS2 gene encoding inducible nitric oxide synthase.

BACKGROUND: Recurrent aphthous stomatitis is a common ulcerative disease of the oral mucosa. Recurrent oral aphthous ulceration is also a feature of the more serious and systemic Behçet's disease. Nitric oxide is a free radical synthesized by one of a family of nitric oxide synthase (NOS) enzymes and is an important regulator of inflammation and immunity. Association of NOS3 gene polymorphisms encoding endothelial nitric oxide synthase has been reported in Behçet's disease but not recurrent aphthous stomatitis. The aim of this study was to investigate any association between NOS2 gene polymorphisms that encode inducible nitric oxide synthase and recurrent aphthous stomatitis. METHODS: This is a case control association study. Eighty-three Jordanian recurrent aphthous stomatitis patients and 83 age, gender and ethnically matched controls were genotyped for three NOS2 single-nucleotide polymorphisms, rs10459953, rs1060822 and rs2297518. Chi-squared analysis was used to compare the allele frequencies and genotypes. RESULTS: There was a significant association between recurrent aphthous stomatitis and inheritance of single-nucleotide polymorphism rs2297518 (P = 0.006). Although no direct association was demonstrated between rs10459953 or rs1060822 and recurrent aphthous stomatitis, a strong linkage disequilibrium was identified between rs1060822 and rs2297518. CONCLUSION: Inheritence of a NOS2 single-nucleotide polymorphism rs2297518 is associated with increased risk of recurrent aphthous stomatitis in a Jordanian population. Confirmatory studies in other populations and investigation of other NOS2 gene polymorphisms will enhance our understanding of the functional basis of this association and help elucidate the role of inducible nitric oxide synthase in recurrent aphthous stomatitis.