Biology subjects

Mozo, R.

Publications and source records attributed to Mozo, R..

3 recordsLinked to original sources

bioRxiv2026

CULTURE AND ISOLATION OF BACTERIA ASSOCIATED WITH MEDITERRANEAN CORALS

Corals harbor a diverse bacterial community that facilitates adaptation and sustains their health. In coral holobiont research, culture-independent approaches have transformed the existing paradigm. Molecular techniques, such as metabarcoding, revealed a high diversity of previously unrecognized bacterial symbionts. Coral microbiota characterization has relied on these techniques over the last decade, but relying solely on them does not provide a detailed understanding of the dynamics of the coral holobiont complex. Returning to classic microbiological methods and in vitro experimentation can yield novel insights into symbiont roles, physiology, and interactions within the holobiont. Under this premise, we aimed to isolate and culture bacteria from four Mediterranean corals. The recovery of 84 pure bacterial isolates and their initial classification based on the 16S rRNA gene revealed substantial diversity among symbionts amenable to culture. Several isolates represent novel species within relevant genera, such as Vibrio, underscoring the value of culture-based studies. All cultures were cryopreserved to guarantee long-term accessibility for future projects. This represents a key step towards describing the roles of bacteria within the coral holobiont, as cultures enable in-depth morphological and physiological characterization of the symbionts and experimental ecology studies.

microbiology↗

bioRxiv2025

Symbiotic bacteria support calcium carbonate precipitation in the Gulf toadfish (Opsanus beta)

Marine fish play a significant yet understudied role in the oceanic carbon cycle through the production of magnesium rich calcium carbonate (CaCO3) precipitates known as ichthyocarbonates. These deposits form in the gut of marine teleost fish in response to salinity, serving as part of their osmoregulation strategy. Through this, marine fish may contribute as much as 9.04 Pg of CaCO3 per year in global new carbonate production, being equivalent to or potentially higher than the production by coccolithophores and pelagic foraminifera. Despite their ecological relevance, the biological mechanisms driving ichthyocarbonate precipitation remain to be fully resolved. Intriguingly, bacteria are consistently found in intimate association with ichthyocarbonate precipitates. Given the widespread capacity of prokaryotes to mediate CaCO precipitation, this association points to a previously unexplored microbial contribution to the process. To investigate the potential role of bacteria in ichthyocarbonate production, we subjected Gulf toadfish (Opsanus beta) to a salinity challenge common to their native range and known to elicit elevated CaCO3 precipitation. To assess the respective contributions of the host and its microbiota to ichthyocarbonate formation in the gut, we characterized the microbiome across the toadfish gut and performed meta-transcriptomic analysis. Across the toadfish gut, we identify a high abundance of vibrios associated with ichthyocarbonates with the metabolic potential for CaCO3 precipitation. Specifically, we observe the expression of the transcriptional activator of urease (ureR) by Photobacterium damselae subsp. damselae, which can induce the precipitation of CaCO3 via the production of bicarbonate. We demonstrate that CaCO precipitation in marine fish may not solely be a host-driven process, but potentially the result of a functional symbiosis with gut-associated Vibrio bacteria. We hypothesize that just as photosymbionts enable corals to build reefs, fish hosts along with their microbial partners may synergistically contribute to oceanic carbonate production. This discovery, if confirmed, expands the role of symbiosis in marine biomineralization and underscores its broader influence on global biogeochemical cycles.

microbiology↗

bioRxiv2025

Genomic connectivity and adaptation signals of the freshwater sponge Ephydatia muelleri across its distribution

1.Freshwater sponges fulfill critical ecological functions, including maintaining water quality, regulating nutrient dynamics, offering habitats for diverse taxa, and serving as a vital food source for various species. However, their patterns of dispersal and genetic connectivity remain inadequately understood, posing significant challenges to effective conservation assessments. We examined genetic connectivity and genetic adaptation to local environmental conditions in Ephydatia muelleri across its geographic range using ddRADseq-derived SNPs from 106 individuals collected from 11 localities spanning North America, Europe, and Asia. Analysis of 3,182 neutral SNPs revealed low connectivity and strong genetic structure among regions within two main genetic clusters of North America and Eurasia, while 115 SNPs identified to be under selection showed considerable evidence for differentiated, polygenic adaptation to light and temperature conditions across sampled locations, as well as selection on gene regulatory processes. These findings align with the "monopolization hypothesis", suggesting that historical climatic and geological conditions of the Last Glacial Maximum, including habitat expansion, contraction, and natural barriers, have contributed more to the current genetic structure of E. muelleri populations than contemporary gene flow, which is restricted by monopolistic habitat colonization by this species. Our results provide novel support for ecological theory on dispersal in aquatic invertebrates, as well as insights into the plasticity of E. muelleri in the face of varying environmental conditions that are fundamentally important for freshwater ecosystem conservation.

evolutionary biology↗