The shrimp gut is a long digestive structure that includes the Foregut (stomach), Midgut (hepatopancreas) and Hindgut (intestine). Each component has different structural, immunity and digestion roles. Given these three gut digestive tract components’ significance, we examined the bacterial compositions of the Foregut, Hindgut, and Midgut digestive fractions. Those bacterial communities’ structures were evaluated by sequencing the V3 hypervariable region of the 16S rRNA gene, while the functions were predicted by PICRUSt2 bioinformatics workflow. Also, to avoid contamination with environmental bacteria, shrimp were maintained under strictly controlled conditions. The pairwise differential abundance analysis revealed differences among digestive tract fractions. The families Rhodobacteraceae and Rubritalaceae registered higher abundances in the Foregut fraction, while in the Midgut, the families with a higher proportion were Aeromonadaceae, Beijerinckiaceae and Propionibacteriaceae. Finally, the Cellulomonadaceae family resulted in a higher proportion in the Hindgut. Regarding the predicted functions, amino acid and carbohydrate metabolism pathways were the primary functions registered for Foregut microbiota; conversely, pathways associated with the metabolism of lipids, terpenoids and polyketides, were detected in the Midgut fraction. In the Hindgut, pathways like the metabolism of cofactors and vitamins along with energy metabolism were enriched. Structural changes were followed by significant alterations in functional capabilities, suggesting that each fraction’s bacteria communities may carry out specific metabolic functions. Results indicate that white shrimp’s gut microbiota is widely related to the fraction analyzed across the digestive tract. Overall, our results suggest a role for the dominant bacteria in each digestive tract fraction, contributing with a novel insight into the bacterial community.

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Zooplankton is a key component in marine ecosystem health assessment. Here, we present a taxonomically comprehensive description of the zooplankton community (0–200 m) based on metabarcoding of the V9 hypervariable region of the 18S rRNA gene of 47 samples collected in the Gulf of Mexico (GoM) during summer 2015. Fourteen phyla were identified Arthropoda were dominant, with Calanidae, Metridinidae, and Euphausiidae as the most conspicuous families. Other abundant phyla were Cnidaria (Hydrozoa), Chordata (Tunicata), and Chaetognatha. The V9-18S sequence data were clustered into 1888 Operational Taxonomic Units (OTUs), of which 39 were cosmopolitan and belonging to various phyla, suggesting the presence of a core community with high local diversity throughout the GoM. Evaluation of metabarcoding sequences abundance showed overall positive correlations with morphologically quantified abundances except for specific groups. Cluster analysis of OTU distributions indicated two primary biographically distinctive groups of stations: one restricted to the Bay of Campeche, while the other occurred in the Central-West GoM, similar to previous descriptions of regional variation of the GoM based on environmental variables. Together these results provide a foundation for broad-scale zooplankton molecular biodiversity assessments in the southern GoM allowing evaluation of the effects of environmental changes on zooplankton communities.

Palabras clave: hongos, biorremediación, petróleo, consumo por contacto directo RESUMENSe cultivó en biorreactores de puente aéreo un consorcio microbiano para estudios ex situ. El consorcio fue obtenido de un cenote contaminado con fenantreno y naftaleno ubicado en la ciudad de Cancún, Quintana Roo, México. En este trabajo se mostró que el consorcio microbiano está también compuesto por hongos con al menos una especie de Cladosporium, además de las bacterias previamente identificadas en trabajos anteriores del grupo de investigación (Pseudomonas, Diplococcus y Enterobacter), por lo que se conforma así un consorcio mixto. Se modeló la cinética de crecimiento de biomasa fúngica utilizando tres modelos: Gompertz, de Von Bertalanffy y logístico para los datos obtenidos por espectrofotometría. Para todos los casos, Von Bertalanffy fue el modelo que se ajustó de manera sobresaliente a los valores experimentales (σ ≤ 0.4). El análisis por estereomicroscopía contribuyó a dar una explicación cualitativa de los mecanismos de asimilación de hidrocarburo en biomasa fúngica, al hacer evidente el contacto directo entre esta biomasa fúngica y el hidrocarburo. Finalmente, cultivos en cajas petri recubiertas con petróleo crudo maya corroboraron que la biomasa fúngica obtenida, produce alguna clase de hidrofobinas que permiten romper la tensión superficial entre la interfase hidrofílica/hidrofóbica, favoreciendo así el contacto con el sustrato y los microorganismos.Key words: fungus, bioremediation, petroleum, direct contact uptake ABSTRACTMicrobial consortium has been cultured in airlift bioreactors for ex situ studies. Consortium was obtained in Cancun city from a naphthalene and phenanthrene polluted sinkhole. This work showed that the microbial consortium is further comprised of at least one species fungi (Cladosporium) additionally to bacteria identified in a previous work from our research group (Pseudomonas, Diplococcus and Enterobacter), forming thus a mixed consortium. Mathematical models were used to adjust biomass

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