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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. [ABSTRACT FROM AUTHOR]

The human ocular surface hosts a bacterial assemblage that integrates a diverse and complex microbiome. This bacterial microbiota is part of a healthy eye and plays a protective role in it. However, this ocular bacterial assemblage may alter the ocular surface inflammation response and can influence the development and progression of dry eye disease. For this reason, the present review describes the changes generated on the ocular surface by bacterial assemblages during the development of dry eye disease. Likewise, the interaction of this microbiota with the other inflammatory factors that influence the development of this disease is analyzed, as well as the use of treatments focused on modifying the bacteria on the ocular surface. [ABSTRACT FROM AUTHOR]

Identifying the core microbiome structure of a metaorganism can be used to monitor the impact of a perturbation against it and the changes in its stability (i.e., dysbiosis), resistance, and resilience. The core‐microbiome interaction regulates holobiont health and homeostasis and is an indicator of the resilience of the whole community. This study determined the exclusive and shared core microbiome taxa of two reef‐building coral species (Pocillopora damicornis and P. verrucosa), as well as the surrounding seawater and sediment, in six coral communities along the Northeastern tropical Pacific region. We also analysed the putative metabolic functions of the most abundant OTUs of these core microbiomes and evaluated the influence of anthropogenic stressors (i.e., tourism, fishery, eutrophication, among others) on core microbiome composition. Bacterial diversity was assessed by sequencing the V4 region of the 16S rRNA. The bacterial families Planctomycetaceae, Oceanospirillaceae, and Moraxellaceae presented the highest relative abundances in corals samples, while Flavobacteriaceae and Rhodobacteraceae dominated in seawater samples. In the sediment samples, Pseudoalteromonadaceae, Oxalobacteraceae, Moraxellaceae, and Pseudonocardiaceae had the highest representation. The core microbiomes of the two coral species, seawater, and sediment, shared 571 OTUs. The P. damicornis core microbiome varied between sites with low and moderately‐high anthropogenic stressors. The core microbiomes of both coral species showed an increase in the relative abundance of the families Planctomycetaceae and Pseudomonadaceae in the sites with moderate‐high anthropogenic stressors, associated with higher values of ammonium, chlorophyll a, and extinction coefficient. In contrast, the core microbiome of P. verrucosa, seawater, and sediments did not vary between sites with different anthropogenic stress conditions. Aerobic chemoheterotrophy was the metabolic function with the highest occurrence in all substrates' core microbiomes, followed by ureolysis and photoautotrophy. [ABSTRACT FROM AUTHOR]

Bacterial assemblages associated with the hermatypic coralsPocillopora damicornis and Pocillopora verrucosa, the surrounding seawater and the sediment at six coral reef sites in the north section of the Tropical Eastern Pacificwere assessed using MiSeq Illumina sequencing of the V4 region of the 16S rDNA. The bacterial microbiota in both coralsspecies, seawater and sediment were stableto seasonal variations. Bacterial assemblages between the same substrates were not significantly different from each otherin the six sites sampled. Interestingly, the bacterial composition between substrates within the same site was significantly different, or not, depending on the conservation status of the site. Moreover, we found species-specific bacterial OTUs in both coral species. Analyzing the relationship between bacterial composition and environmental variables revealed a positive correlationbetween bacterial assemblagesanddissolved oxygen, ammonium and silicate. [ABSTRACT FROM AUTHOR]

The bacterial assemblages associated with Acropora palmata from the Mexican Caribbean Sea and the Gulf of Mexico were analyzed by high throughput sequencing of the 16S rRNA gene. Samples were taken from four substrates: apparently healthy corals, corals with white band disease, and the seawater and sediment surrounding these corals. The bacterial assemblages showed no significant differences among sampling sites and analyzed substrates, except between apparently healthy A. palmata and the sediments. In contrast, bacterial dominance patterns showed important differences; members of the genera Stenotrophomonas , Spirochaeta, and Pseudomonas dominated the samples of healthy corals, while Clostridium, Tepidibacter, and Desulfovibrio had higher relative abundances in the diseased colonies. As expected, sample types (water and sediment) also showed different bacterial patterns: the genera Enterobacter , Vibrio , Synechococcus, and Pseudoalteromonas were dominant in the seawater, while Thioprofundum and Pleorocapsa presented high relative abundances in the sediment. The genera Stenotrophomonas, Pseudomonas, Clostridium, Tepidibacter, Enterobacter, Synechococcus, Spirochaeta, Pleurocapsa, Vibrio, Enterococcus, and Pseudoalteromonas mainly contributed to the dissimilarities between the substrates. This study contributes to the knowledge of bacterial assemblages associated with A. palmata in Mexican coral reefs and broadens the contributes to understanding of the effects of white band disease. • The bacterial assemblages in all substrates were similar in all sampling sites despite the geographic distance. • The bacterial abundance associated with the coral Acropora palmata is lower than in seawater and sediments. • The dominant bacterial genera of the bacterial assemblage were different for each substrate. • Healthy and sick coral colonies of A. palmata show differences in their dominant bacterial genera. [ABSTRACT FROM AUTHOR]

The hermatypic coral ecosystems of the southern coast of Jalisco, Mexico, present an important species richness and coverage for the Mexican Central Pacific. However, knowledge of these ecosystems of the Jalisco coast is fragmented. Studies have concentrated on few localities, employing a limited number of coral health indicators, and gaps still remain in the knowledge of ecosystem structure and its local and mesoscale variation. This study evaluated spatial variations in the coral assemblage structure in six sites on the southern coast of Jalisco, Mexico, five of which had never been studied before. Sampling was conducted in September 2019, utilizing a total of 35 transects (each of 25 m in length). The cover of each coral species was recorded, as well as other benthic groups and substrate types. Different community attributes, patterns of similarity in coral species and their relationships with the benthic habitat structure were evaluated in each site. The results showed that the observed richness (8 species) represented 83.7% of that expected by chance. Significant spatial variation was found between coral patch sites and coral community sites, in terms of species richness, Shannon diversity and live coral cover, as well as in the structure of the coral assemblage and the benthic habitat. The results evidenced these conditions despite the existence of a considerable dominance of branched corals of the genus Pocillopora. The species that contributed most to the differences between coral patch sites and coral community sites were Pocillopora damicornis , Pocillopora capitata and Pocillopora verrucosa. For their part, the benthic habitat structural elements that favored the differences between site conditions were live coral cover and turf. • An analysis of coral assemblages from new sites at the Mexican Pacific is presented. • A significant coral assemblage spatial variation was found among sites. • Different coral development was found among sites. • The Pocillopora branching corals dominated in most sites. • The coral assemblage was correlated to the cover of live coral and calcareous algae. [ABSTRACT FROM AUTHOR]