Browsing by Author "Keller-Costa, Tina"
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- A multi-component pheromone in the urine of dominant male tilapia (Oreochromis mossambicus) reduces aggression in rivalsPublication . Keller-Costa, Tina; Saraiva, João L.; Hubbard, Peter; Barata, Eduardo Nuno; Canário, Adelino V. M.Males often use scent to communicate their dominance, and to mediate aggressive and breeding behaviors. In teleost fish, however, the chemical composition of male pheromones is poorly understood. Male Mozambique tilapia, Oreochromis mossambicus, use urine that signals social status and primes females to spawn. The urinary sex pheromone directed at females consists of 5 beta-pregnane-3 alpha,17 alpha,20 beta-triol 3-glucuronate and its 20 alpha-epimer. The concentration of these is positively correlated with male social rank. This study tested whether dominant male urine reduces aggression in receiver males, and whether the pregnanetriol 3-glucuronates also reduce male-male aggression. Males were allowed to fight their mirror image when exposed to either: i) water control or a chemical stimulus; ii) dominant male urine (DMU); iii) C18-solid phase (C18-SPE) DMU eluate; iv) C18-SPE DMU eluate plus filtrate; v) the two pregnanetriol 3-glucuronates (P3Gs); or vi) P3Gs plus DMU filtrate. Control males mounted an increasingly aggressive fight against their image over time. However, DMU significantly reduced this aggressive response. The two urinary P3Gs did not replicate the effect of whole DMU. Neither did the C18-SPE DMU eluate, containing the P3Gs, alone, nor the C18-SPE DMU filtrate to which the two P3Gs were added. Only exposure to reconstituted DMU (C18-SPE eluate plus filtrate) restored the aggression-reducing effect of whole DMU. Olfactory activity was present in the eluate and the polar filtrate in electro-olfactogram studies. We conclude that P3Gs alone have no reducing effect on aggression and that the urinary signal driving off male competition is likely to be a multi-component pheromone, with components present in both the polar and non-polar urine fractions.
- An artificial selection procedure enriches for known and suspected chitin degraders from the prokaryotic rare biosphere of multiple marine biotopesPublication . Meunier, Laurence; Keller-Costa, Tina; Cannella, David; Gonçalves, Jorge Manuel Santos; Dechamps, Etienne; Marques, Matilde; Costa, Rodrigo; George, Isabelle F.Biological of chitin-degrading microbial communities change across marine biotopes, but efforts to isolate chitin degraders within these communities in the laboratory have seldom been attempted. We characterized the prokaryotic communities associated with the marine sponge Sarcotragus spinosulus, the octocoral Eunicella labiata, and their surrounding sediment and seawater and applied an artificial selection procedure to enrich bacterial consortia capable of degrading chitin from the abovementioned biotopes. Throughout the procedure, chitin degradation was monitored, and the taxonomic composition was studied along four successive enrichment cultures from each biotope. Results The naturally occurring prokaryotic communities of the two host species (Sarcotragus spinosulus and Eunicella labiata) were distinct from each other and from those of seawater and sediments, even though they were co-inhabiting the same geographic area. We found that low-abundance bacteria from the rare biosphere were recruited in the enrichment cultures from all biotopes, while dominant bacterial symbionts likely to play a role in chitin degradation within marine sponges and octocorals remained “unculturable” under our experimental conditions. Well-known chitin degraders such as Vibrio, Pseudoalteromonas and Aquimarina, as well as other taxa not known or poorly known for their role(s) in chitin degradation such as Aureivirga, Halodesulfovibrio, Motilimonas, Muricauda, Psychromonas, Poseidonibacter, Reichenbachiella, and Thalassotalea, among others, were enriched using our artificial selection approach. Distinct chitin-degrading consortia were enriched from each marine biotope, highlighting the feasibility of this approach in fostering the discovery of novel microorganisms and enzymes involved in chitin degradation pathways of relevance in applied biotechnology. Conclusion This study unveils distinct bacterial consortia possessing moderate to high efficiency at degrading chitin. They were composed of a mix of known chitin degraders, known chitin utilizers and many taxa poorly or not yet known for their role(s) in chitin degradation such as Aureivirga, Psychromonas, Motilimonas, Reichenbachiella, or Halodesulfovibrio. The latter taxa are potential key players in marine chitin degradation whose study could lead to the discovery of novel enzyme variants able to degrade chitin and its derivatives.
- Assessing the genomic composition, putative ecological relevance and biotechnological potential of plasmids from sponge bacterial symbiontsPublication . Oliveira, Vanessa; Polónia, Ana R. M.; Cleary, Daniel F. R.; Huang, Yusheng M.; de Voogd, Nicole J.; Keller-Costa, Tina; Costa, Rodrigo; Gomes, Newton C. M.Plasmid-mediated transfer of genes can have direct consequences in several biological processes within sponge microbial communities. However, very few studies have attempted genomic and functional characterization of plasmids from marine host-associated microbial communities in general and those of sponges in particular. In the present study, we used an endogenous plasmid isolation method to obtain plasmids from bacterial symbionts of the marine sponges Stylissa carteri and Paratetilla sp. and investigated the genomic composition, putative ecological relevance and biotechnological potential of these plasmids. In total, we isolated and characterized three complete plasmids, three plasmid prophages and one incomplete plasmid. Our results highlight the importance of plasmids to transfer relevant genetic traits putatively involved in microbial symbiont adaptation and host-microbe and microbe-microbe interactions. For example, putative genes involved in bacterial response to chemical stress, competition, metabolic versatility and mediation of bacterial colonization and pathogenicity were detected. Genes coding for enzymes and toxins of biotechnological potential were also detected. Most plasmid prophage coding sequences were, however, hypothetical proteins with unknown functions. Overall, this study highlights the ecological relevance of plasmids in the marine sponge microbiome and provides evidence that plasmids of sponge bacterial symbionts may represent an untapped resource of genes of biotechnological interest.
- Chemical communication in tilapia: a comparison of Oreochromis mossambicus with O. niloticusPublication . Hubbard, Peter; Mota, Vasco; Keller-Costa, Tina; Silva, José P. da; Canario, Adelino V. M.In allopatric speciation species differentiation generally results from different selective pressures in different environments, and identifying the traits responsible helps to understand the isolation mechanism(s) involved. Male Mozambique tilapia (Oreochromis mossambicus) use urine to signal dominance; furthermore, 5-pregnane-3,17,20-triol-3-glucuronide (and its -epimer, 5-pregnane-3,17,20-triol-3-glucuronide), in their urine is a potent pheromone, the concentration of which is correlated with social status. The Nile tilapia (O. niloticus) is a close relative; species divergence probably resulted from geographical separation around 6 million years ago. This raises the question of whether the two species use similar urinary chemical cues during reproduction. The olfactory potency of urine, and crude extracts, from either species was assessed by the electro-olfactogram and the presence of the steroid glucuronides in urine from the Nile tilapia by liquid-chromatography/mass spectrometry. Both species showed similar olfactory sensitivity to urine and respective extracts from either species, and similar sensitivity to the steroid glucuronides. 5-pregnan-3,17,20-triol-3-glucuronide was present at high concentrations (approaching 0.5 mM) in urine from Nile tilapia, with 5-pregnan-3,17,20-triol-3-glucuronide present at lower concentrations, similar to the Mozambique tilapia. Both species also had similar olfactory sensitivity to estradiol-3-glucuronide, a putative urinary cue from females. Together, these results support the idea that reproductive chemical cues have not been subjected to differing selective pressure. Whether these chemical cues have the same physiological and behavioural roles in O. niloticus as O. mossambicus remains to be investigated.
- Chemical diplomacy in male tilapia: urinary signal increases sex hormone and decreases aggressionPublication . Saraiva, João; Keller-Costa, Tina; Hubbard, Peter; Rato, Ana; Canario, AdelinoAndrogens, namely 11-ketotestosterone (11KT), have a central role in male fish reproductive physiology and are thought to be involved in both aggression and social signalling. Aggressive encounters occur frequently in social species, and fights may cause energy depletion, injury and loss of social status. Signalling for social dominance and fighting ability in an agonistic context can minimize these costs. Here, we test the hypothesis of a 'chemical diplomacy' mechanism through urinary signals that avoids aggression and evokes an androgen response in receiver males of Mozambique tilapia (Oreochromis mossambicus). We show a decoupling between aggression and the androgen response; males fighting their mirror image experience an unresolved interaction and a severe drop in urinary 11KT. However, if concurrently exposed to dominant male urine, aggression drops but urinary 11KT levels remain high. Furthermore, 11KT increases in males exposed to dominant male urine in the absence of a visual stimulus. The use of a urinary signal to lower aggression may be an adaptive mechanism to resolve disputes and avoid the costs of fighting. As dominance is linked to nest building and mating with females, the 11KT response of subordinate males suggests chemical eavesdropping, possibly in preparation for parasitic fertilizations.
- Comparative genomics reveals complex natural product biosynthesis capacities and carbon metabolism across host-associated and free-living Aquimarina (Bacteroidetes, Flavobacteriaceae) speciesPublication . Silva, Sandra G.; Blom, Jochen; Keller-Costa, Tina; Costa, RodrigoThis 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.
- Contamination analysis of Arctic ice samples as planetary field analogs and implications for future life-detection missions to Europa and EnceladusPublication . Coelho, Lígia F.; Blais, Marie-Amélie; Matveev, Alex; Keller-Costa, Tina; Vincent, Warwick F.; Da Silva Costa, Rodrigo; Martins, Zita; Canário, JoãoMissions 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.
- Draft genome sequence of Vibrio chagasii 18LP, isolated from Gilthead Seabream (Sparus aurata) larvae reared in aquaculturePublication . Sanches-Fernandes, Gracinda M. M.; Califano, Gianmaria; Keller-Costa, Tina; Castanho, Sara; Soares, Florbela; Ribeiro, Laura; Pousão-Ferreira, Pedro; Mata, Leonardo; Costa, RodrigoWe report the draft genome sequence of Vibrio chagasii strain 18LP, isolated from gilthead seabream larvae at a fish hatchery research station in Portugal. The genome presents numerous features underlying opportunistic behavior, including genes coding for toxin biosynthesis and tolerance, host cell invasion, and heavy metal resistance.
- Draft genome sequence of vibrio jasicida 20LP, an opportunistic bacterium isolated from fish larvaePublication . Sanches-Fernandes, Gracinda M. M.; Califano, Gianmaria; Keller-Costa, Tina; Castanho, Sara; Soares, Florbela; Ribeiro, Laura; Pousão-Ferreira, Pedro; Mata, Leonardo; Costa, RodrigoWe present the genome sequence of Vibrio jasicida 20LP, a bacterial strain retrieved from larvae of gilthead seabream (Sparus aurata), a highly valuable, model fish species in land-based aquaculture. Annotation of the V. jasicida 20LP genome reveals multiple genomic features potentially underpinning opportunistic associations with diverse marine animals.
- Genome sequence of the marine alphaproteobacterium sp. EG35 isolated from the temperate octocoralPublication . Keller-Costa, Tina; Madureira, Selene; Fernandes, Ana S.; Kozma, Lydia; Gonçalves, Jorge Manuel Santos; Barroso, Cristina; Egas, Conceição; Costa, RodrigoWe report the genome sequence of sp. strain EG35 isolated from the octocoral sampled off the coast of Portugal. We reveal the coding potential for the biosynthesis of polyhydroxyalkanoates - biodegradable polyesters that may serve bioplastics production, diverse homoserine lactone-like communication signals, and four putatively novel natural products.
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