The Mexican Central Pacific is located in a zone of oceanographic transition between two biogeographic provinces with particular conditions that affect the associated fauna. The objective of this study was to evaluate the variation of hermatypic coral assemblages in this region and to determine their relationship with the heterogeneity of the benthonic habitat and spatial variables. A total of 156 transects were carried out at 41 sites in the years 2010 and 2011. The sampling effort returned 96.7% of the coral richness expected for the area, with a total of 15 species recorded. The results showed that richness, diversity and cover of corals varied only at the site and state scales. However, the composition and coverage of all coral species, as well as the benthonic habitat structure, differed significantly across the study scales (i.e. sites, zones and states). Canonical redundancy analysis showed that variation in the richness, diversity and assemblages of corals was explained by the cover of live corals, articulated calcareous algae, sandy substrate, sponges and fleshy macroalgae. This study suggests that local scale (i.e. site) variation in the coral assemblages of the Mexican Central Pacific is the result of the heterogeneity of the benthonic habitat, while geomorphological and oceanographic characteristics play a greater role at regional scale.

In this study, the bacterial microbiota associated with apparently healthy corals of Acropora palmata, Orbicella faveolata, and Porites porites and the surrounding seawater and sediment were evaluated via the MiSeq Illumina sequencing of the V4 region of 16S rRNA at three reef sites in the Mexican Caribbean. Bacterial assemblages associated with apparently healthy corals and sediments showed no significant differences between sites. The colonies of A. palmata showed a dominance of families Amoebophilaceae, Spirochaetaceae, Myxococcaceae, and Cyclobacteriaceae. Meanwhile, the colonies of O. faveolata and P. porites revealed a high prevalence of the Rhodobacteraceae and Kiloniellaceae families. The families Rhodobacteraceae, Cryomorphaceae, Cyanobiaceae, and Flavobacteriaceae were predominant in seawater samples, while Pirellulaceae, Nitrosococcaceae, and Woeseiaceae were predominant in sediments. Variations in A. palmata bacterial assemblages were correlated with salinity, sea surface temperature, and depth. These variables, along with nitrate, phosphate, and ammonium concentrations, were also correlated with changes in the bacterial composition of P. porites, seawater, and sediments. However, none of the environmental variables were related to the bacterial taxa of O. faveolata. Aerobic chemoheterotrophy and fermentation, followed by nitrate reduction and ureolysis, were the metabolic functions with the highest occurrence in the bacterial assemblages associated with all substrates.

The human microbiome has a crucial role in the homeostasis and health of the host. These microorganisms along with their genes are involved in various processes, among these are neurological signaling, the maturation of the immune system, and the inhibition of opportunistic pathogens. In this sense, it has been shown that a healthy ocular microbiota acts as a barrier against the entry of pathogens, contributing to the prevention of infections. In recent years, a relationship has been suggested between microbiota dysbiosis and the development of neurodegenerative diseases. In patients with glaucoma, it has been observed that the microbiota of the ocular surface, intraocular cavity, oral cavity, stomach, and gut differ from those observed in healthy patients, which may suggest a role in pathology development, although the evidence remains limited. The mechanisms involved in the relationship of the human microbiome and this neurodegenerative disease remain largely unknown. For this reason, the present review aims to show a broad overview of the influence of the structure and composition of the human oral and gut microbiota and relate its dysbiosis to neurodegenerative diseases, especially glaucoma.

The Mexican Central Pacific (MCP) region has discontinuous coral ecosystems with different protection and anthropogenic disturbance. Characterizing the bacterial assemblage associated with the sea urchin Toxopneustes roseus and its relationship with environmental variables will contribute to understanding the species’ physiology and ecology. We collected sea urchins from coral ecosystems at six sites in the MCP during the summer and winter for two consecutive years. The spatial scale represented the most important variation in the T. roseus bacteriome, particularly because of Isla Isabel National Park (PNII). Likewise, spatial differences correlated with habitat structure variables, mainly the sponge and live coral cover. The PNII exhibited highly diverse bacterial assemblages compared to other sites, characterized by families associated with diseases and environmental stress (Saprospiraceae, Flammeovirgaceae, and Xanthobacteraceae). The remaining five sites presented a constant spatiotemporal pattern, where the predominance of the Campylobacteraceae and Helicobacteraceae families was key to T. roseus’ holobiont. However, the dominance of certain bacterial families, such as Enterobacteriaceae, in the second analyzed year suggests that Punto B and Islas e islotes de Bahía Chamela Sanctuary were exposed to sewage contamination. Overall, our results improve the understanding of host-associated bacterial assemblages in specific time and space and their relationship with the environmental condition.