Biology subjects

Arrieta, J. M.

Publications and source records attributed to Arrieta, J. M..

3 recordsLinked to original sources

bioRxiv2025

Diversity and community structure of aerobic anoxygenic phototrophic bacteria are shaped by the deep chlorophyll maximum

The surface ocean exhibits strong vertical gradients in light, nutrients, and temperature, shaping the phytoplankton distribution which often defines a deep chlorophyll maximum (DCM). Aerobic anoxygenic phototrophic (AAP) bacteria inhabit the euphotic zone, with their abundances following the chlorophyll a variability. While AAP bacterial communities are known to differ across regions with contrasting environmental conditions, their vertical distribution remains poorly understood. We hypothesized that the diversity and community structure of AAP bacteria would vary across the vertical gradient, in relation to changes in environmental variables and following the DCM profile. To test this hypothesis, we studied the composition of AAP communities at different depths along the DCM structure in the South and Central Atlantic Ocean, by means of amplicon sequencing of the pufM gene. The results show significant differences in richness, community structure, and taxonomic composition of samples from different layers of the DCM, highlighting the dependance of AAP bacteria on its structure. Remarkably, the use of primers with broad phylogenetic coverage enabled the recovery of several phylogroups previously detected only through metagenomics. We show that they represent a significant fraction of marine AAP communities, provide clues on their ecological preferences, and confirm their association with the family Candidatus Luxescamonaceae, with genomic potential for carbon fixation.

ecology↗

bioRxiv2025

Isolation and primary culture of Octopus vulgaris cells: Assessment of their proliferative capacity

The octopus cell culture system represents a useful tool in various fields, such as biological studies and sustainable octopus production. In this paper, we describe the isolation procedure and culture protocols, metabolic activity, and the proliferative capacity assessment of the common octopus (Octopus vulgaris) cells, at three different life stages: embryo, paralarvae and adult. Isolation of cells was carried out with minimum essential medium (MEM) or Leibovitz L-15 medium, using 0.4 % type I collagenase for 2 (paralarvae and embryo) or 3 h (adult) at 25 {degrees}C. Isolated cells showed significant metabolic activity, demonstrating their viability for in vitro studies. The culture of isolated cells in MEM or L-15 supplemented with different sera (4 % fetal bovine serum (FBS), 10 % FBS and 5 % haemolymph (HEMO)) was viable for 168 h, although the survival of different cell types was variable. A detachment protocol using trypsin was also successfully developed. Finally, isolated muscle cells from both paralarval and adult specimens were marked with the mitotic indicator PHH3. Results from flow cytometry analysis showed that all developmental stages examined contained cells in mitotic phase, with embryos XII-XIII showing the highest proportion. This study provides novel guidelines for the in vitro culture of O. vulgaris cells, which are useful for the future development of cellular aquaculture, understood as the production of lab-grown meat for this species. Moreover, the results reported in this communication could contribute to reduce the use of animals for scientific purposes as well as providing a new option for human consumption of cephalopods.

cell biology↗

bioRxiv2019

Metabolic Architecture of the Deep Ocean Microbiome

The deep sea, the largest compartment of the ocean, is an essential component of the Earth system, but the functional exploration of its microbial communities lags far behind that of other marine realms. Here we analyze 58 bathypelagic microbial metagenomes from the Atlantic, Indian, and Pacific Oceans in an unprecedented sampling effort from the Malaspina Global Expedition, to resolve the metabolic architecture of the deep ocean microbiome. The Malaspina Deep-Sea Gene Collection, 71% of which consists of novel genes, reveals a strong dichotomy between the functional traits of free-living and particle-attached microorganisms, and shows relatively patchy composition challenging the paradigm of a uniform dark ocean ecosystem. Metagenome Assembled Genomes uncovered 11 potential new phyla, establishing references for deep ocean microbial taxa, and revealed mixotrophy to be a widespread trophic strategy in the deep ocean. These results expand our understanding of the functional diversity, metabolic versatility, and carbon cycling in the largest ecosystem on Earth.\n\nOne Sentence SummaryA whole community genomic survey of the deep microbiome sheds light on the microbial and functional diversity of the dark ocean.

microbiology↗