Chemical identification of dominance pheromones in Mozambique tilapia males

Fishes use pheromones (intraspecific chemical messages) to coordinate reproduction, migration and social interactions but their identity is rarely known. In the Mozambique tilapia (Oreochromis mossambicus), a social, lek-breeding cichlid, reproduction and male aggression are mediated through urinary cues released by dominant males. The main goal of this thesis was the chemical identification of such pheromones and establishment of their function(s). Two steroid glucuronates (5β-pregnane-3α,17,20β-triol 3-glucuronate and its 20α-epimer) were identified as the most potent odorants in male urine. Both steroids act, via a specific olfactory receptor mechanism, on the females’ endocrine axis, stimulating oocyte maturation. However, in contrast to dominant male urine, these steroids on their own do not reduce male aggression in receivers, suggesting that multiple, as yet unidentified, compounds are likely responsible for this effect. In conclusion, dominant tilapia males release pregnanetriol glucuronates via their urine as a sex pheromone, likely to synchronize spawning and enhance reproductive success; Resumo: Indentificação química das feromonas de dominância dos machos da tilápia moçambicana Os peixes usam feromonas (mensagens químicas intra-específicas) para coordenar a reprodução, migrações e interações sociais, cuja identidade é pouco conhecida. Na tilápia moçambicana (Oreochromis mossambicus), um ciclídeo social que se reproduz em agregações, a reprodução e agressão entre machos são mediados por odores libertados pela urina de machos dominantes. O objetivo principal desta tese é determinar a identidade e função destes. Os esteróides 5β-pregnane- 3α,17,20β-triol 3-glucurónido e o seu epímero 20α foram identificados como os compostos mais potentes presentes na urina de machos. Ambos atuam no eixo endócrino reprodutor das fêmeas através de um recetor olfativo específico e estimulam a maturação dos ovócitos. Ao contrário da urina dos machos, estes esteróides por si só não reduzem a agressão dos machos recetores, sugerindo a presença de múltiplos compostos, ainda por identificar, responsáveis por este efeito. Conclui-se que os machos dominantes da tilápia libertam uma feromona sexual através da urina que sincroniza a reprodução e melhora o seu sucesso reprodutor

Genomic insights into aquimarina sp. strain EL33, a bacterial symbiont of the gorgonian coral eunicella labiata.

To address the metabolic potential of symbiotic Aquimarina spp., we report here the genome sequence of Aquimarina sp. strain EL33, a bacterium isolated from the gorgonian coral Eunicella labiata This first-described (to our knowledge) animal-associated Aquimarina genome possesses a sophisticated repertoire of genes involved in drug/antibiotic resistance and biosynthesis

Comparative genomics reveals complex natural product biosynthesis capacities and carbon metabolism across host-associated and free-living Aquimarina (Bacteroidetes, Flavobacteriaceae) species

This study determines the natural product biosynthesis and full coding potential within the bacterial genus Aquimarina. Using comprehensive phylogenomics and functional genomics, we reveal that phylogeny instead of isolation source [host-associated (HA) vs. free-living (FL) habitats] primarily shape the inferred metabolism of Aquimarina species. These can be coherently organized into three major functional clusters, each presenting distinct natural product biosynthesis profiles suggesting that evolutionary trajectories strongly underpin their secondary metabolite repertoire and presumed bioactivities. Aquimarina spp. are highly versatile bacteria equipped to colonize HA and FL microniches, eventually displaying opportunistic behaviour, owing to their shared ability to produce multiple glycoside hydrolases from diverse families. We furthermore uncover previously underestimated, and highly complex secondary metabolism for the genus by detecting 928 biosynthetic gene clusters (BGCs) across all genomes, grouped in 439 BGC families, with polyketide synthases (PKSs), terpene synthases and non-ribosomal peptide synthetases (NRPSs) ranking as the most frequent BGCs encoding drug-like candidates. We demonstrate that the recently described cuniculene (trans-AT PKS) BGC is conserved among, and specific to, the here delineated A. megaterium-macrocephali-atlantica phylogenomic clade. Our findings provide a timely and in-depth perspective of an under-explored yet emerging keystone taxon in the cycling of organic matter and secondary metabolite production in marine ecosystems.Portuguese Science and Technology Foundation (FCT)Portuguese Foundation for Science and Technology [PTDC/MAR-BIO/1547/2014, UID/BIO/04565/2013]Institute for Bioengineering and Biosciences, Programa Operacional Regional de Lisboa 2020 [007317]FCTPortuguese Foundation for Science and Technology [PD/BD/143029/2018

Genomic blueprints of sponge-prokaryote symbiosis are shared by low abundant and cultivatable Alphaproteobacteria

Marine sponges are early-branching, filter-feeding metazoans that usually host complex microbiomes comprised of several, currently uncultivatable symbiotic lineages. Here, we use a low-carbon based strategy to cultivate low-abundance bacteria from Spongia officinalis. This approach favoured the growth of Alphaproteobacteria strains in the genera Anderseniella, Erythrobacter, Labrenzia, Loktanella, Ruegeria, Sphingorhabdus, Tateyamaria and Pseudovibrio, besides two likely new genera in the Rhodobacteraceae family. Mapping of complete genomes against the metagenomes of S. officinalis, seawater, and sediments confirmed the rare status of all the above-mentioned lineages in the marine realm. Remarkably, this community of low-abundance Alphaproteobacteria possesses several genomic attributes common to dominant, presently uncultivatable sponge symbionts, potentially contributing to host fitness through detoxification mechanisms (e.g. heavy metal and metabolic waste removal, degradation of aromatic compounds), provision of essential vitamins (e.g. B6 and B12 biosynthesis), nutritional exchange (especially regarding the processing of organic sulphur and nitrogen) and chemical defence (e.g. polyketide and terpenoid biosynthesis). None of the studied taxa displayed signs of genome reduction, indicative of obligate mutualism. Instead, versatile nutrient metabolisms along with motility, chemotaxis, and tight-adherence capacities - also known to confer environmental hardiness - were inferred, underlying dual host-associated and free-living life strategies adopted by these diverse sponge-associated Alphaproteobacteria.PTDC/MAR-BIO/1547/2014; full PhD scholarship from the Erasmus Mundus Programme/SALAM EMA2 lot7/SALA1206422info:eu-repo/semantics/publishedVersio

Olfactory sensitivity to steroid glucuronates in Mozambique tilapia suggests two distinct and specific receptors for pheromone detection

Cichlids offer an exciting opportunity to understand vertebrate speciation; chemical communication could be one of the drivers of African cichlid radiation. Chemical signals mediate key aspects in the lives of vertebrates and often are species specific. Dominant male Mozambique tilapia [Oreochromis mossambicus (Peters 1852)] release a sex pheromone, 5 beta-pregnan-3 alpha,17 alpha,20 beta-triol 3-glucuronate and its 20 alpha-epimer, via their urine. The objective of this study was to assess the sensitivity, specificity and versatility of the olfactory system of O. mossambicus to other steroids and their conjugates using the electro-olfactogram. Oreochromis mossambicus was sensitive to several 3-glucuronidated steroids, but did not respond to prostaglandins, unconjugated steroids or 17- or 20-conjugated steroids. Stimulation of the olfactory epithelium with increasing concentrations (1 pmol l(-1) to 10 mu mol l(-1)) of 5 beta-pregnan-3 alpha, 17 alpha,20 beta-triol 3-glucuronate, 5 beta-pregnan-3 alpha, 17 alpha,20 beta-triol 3-glucuronate, 3 alpha,17 alpha-dihydroxy-5 beta-pregnan-20-one 3-glucuronate, etiocholanolone 3 alpha-glucuronate and 17 beta-estradiol 3-glucuronate produced characteristic sigmoidal concentration-response curves. However, tilapia were most sensitive to 17 beta-estradiol-3-glucuronate, which also had the lowest apparent EC50 and maximal response amplitude. Cross-adaptation and binary mixture experiments suggested that 5 beta,3 alpha-reduced pregnan-and androstan-3-glucuronates share (a) common olfactory receptor(s), whereas 17 beta-estradiol 3-glucuronate is detected via (a) distinct olfactory receptor(s). In conclusion, the Mozambique tilapia has evolved high olfactory sensitivity and specificity to 3-glucuronidated steroids through two distinct olfactory receptor types; one detecting a male sex pheromone and a second detecting 17 beta-estradiol 3-glucuronate, a putative female-derived signal. However, O. mossambicus differs markedly in its olfactory perception from the more recently derived East African cichlid Astatotilapia burtoni, suggesting that chemical communication could, indeed, be involved in speciation.Science and Technology Foundation (FCT), Portugal [POCI/BIA-BDE/55463/2004]; FCT [SFRH/BD/46192/2008]info:eu-repo/semantics/publishedVersio

Metagenome-assembled genome sequences of three uncultured planktomarina sp. strains from the Northeast Atlantic Ocean

We report three metagenome-assembled genomes (MAGs) of Planktomarina strains from coastal seawater (Portugal) to help illuminate the functions of understudied Rhodobacteraceae bacteria in marine environments. The MAGs encode proteins involved in aerobic anoxygenic photosynthesis and a versatile carbohydrate metabolism, strengthening the role of Planktomarina species in oceanic carbon cycling.Portuguese Foundation for Science and Technology: EXPL/MAR-EST/1664/2013 PTDC/MAR-BIO/1547/2014, UIDB/04565/2020, PD/BD/143029/2018, CEECIND/00788/2017,PTDC/BIA-MIC/31996/2017;Institute of Bioengineering and Biosciences (iBB) by the Programa Operacional Regional de Lisboa 007317; Helmholtz Association VH-NG-1248.info:eu-repo/semantics/publishedVersio

Genome sequencing suggests diverse secondary metabolism in coral-associated aquimarina megaterium

We report here the genome sequences of three Aquimarina megaterium strains isolated from the octocoral Euniceila labiata. We reveal a coding potential for versatile carbon metabolism and biosynthesis of natural products belonging to the polyketide, nonribosomal peptide, and terpene compound classes.info:eu-repo/semantics/publishedVersio

The Roseibium album (Labrenzia alba) genome possesses multiple symbiosis factors possibly underpinning host-microbe relationships in the Marine Benthos

Here, we announce the genomes of eight Roseibium album (synonym Labrenzia alba) strains that were obtained from the octocoral Eunicella labiata. Genome annotation revealed multiple symbiosis factors common to all genomes, such as eukaryotic-like repeat protein- and multidrug resistance-encoding genes, which likely underpin symbiotic relationships with marine invertebrate hosts.info:eu-repo/semantics/publishedVersio

The gorgonian coral Eunicella labiata hosts a distinct prokaryotic consortium amenable to cultivation

Microbial communities inhabiting gorgonian corals are believed to benefit their hosts through nutrient provision and chemical defence; yet much remains to be learned about their phylogenetic uniqueness and cultivability. Here, we determined the prokaryotic community structure and distinctiveness in the gorgonian Eunicella labiata by Illumina sequencing of 16S rRNA genes from gorgonian and seawater metagenomic DNA. Furthermore, we used a 'plate-wash' methodology to compare the phylogenetic diversity of the 'total' gorgonian bacteriome and its 'cultivatable' fraction. With 1016 operational taxonomic units (OTUs), prokaryotic richness was higher in seawater than in E. labiata where 603 OTUs were detected, 68 of which were host-specific. Oceanospirillales and Rhodobacterales predominated in the E. labiata communities. One Oceanospirillales OTU, classified as Endozoicomonas, was particularly dominant, and closest relatives comprised exclusively uncultured clones from other gorgonians. We cultivated a remarkable 62% of the bacterial symbionts inhabiting E. labiata: Ruegeria, Sphingorhabdus, Labrenzia, other unclassified Rhodobacteraceae, Vibrio and Shewanella ranked among the 10 most abundant genera in both the cultivation-independent and dependent samples. In conclusion, the E. labiata microbiome is diverse, distinct from seawater and enriched in (gorgonian)-specific bacterial phylotypes. In contrast to current understanding, many dominant E. labiata symbionts can, indeed, be cultivated.Portuguese Foundation for Science and Technology [EXPL/MAR-EST/1664/2013, SFRH/BPD/34282/2006]German Volkswagen (VW) foundation [Az. 81 040-2]info:eu-repo/semantics/publishedVersio

Contamination analysis of Arctic ice samples as planetary field analogs and implications for future life-detection missions to Europa and Enceladus

Missions to detect extraterrestrial life are being designed to visit Europa and Enceladus in the next decades. The contact between the mission payload and the habitable subsurface of these satellites involves significant risk of forward contamination. The standardization of protocols to decontaminate ice cores from planetary field analogs of icy moons, and monitor the contamination in downstream analysis, has a direct application for developing clean approaches crucial to life detection missions in these satellites. Here we developed a comprehensive protocol that can be used to monitor and minimize the contamination of Arctic ice cores in processing and downstream analysis. We physically removed the exterior layers of ice cores to minimize bioburden from sampling. To monitor contamination, we constructed artificial controls and applied culture-dependent and culture-independent techniques such as 16S rRNA amplicon sequencing. We identified 13 bacterial contaminants, including a radioresistant species. This protocol decreases the contamination risk, provides quantitative and qualitative information about contamination agents, and allows validation of the results obtained. This study highlights the importance of decreasing and evaluating prokaryotic contamination in the processing of polar ice cores, including in their use as analogs of Europa and Enceladus.info:eu-repo/semantics/publishedVersio