Biology subjects

Leite, R. B.

Publications and source records attributed to Leite, R. B..

4 recordsLinked to original sources

bioRxiv2023

Transcriptional profiling of populations in the clam Ruditapes decussatus suggests genetically determined differentiation in gene-expression along parallel temperature gradients and between races of the Atlantic Ocean and West Mediterranean sea

Ongoing ocean warming due to climate change poses new challenges for marine life and its exploitation. We have used transcriptomics to find genetically-based responses to increased temperature in natural populations of the marine clam Ruditapes decussatus living along parallel thermal gradients in southern Europe. Clams of the Atlantic and West Mediterranean races were collected in a northern (cool) and a southern (warm) localities. The animals were kept in running seawater in the warm, Atlantic southern locality for a 15-week period, during which water temperature raised to typical southern European summer values. After this period, the expression profile was obtained for a total of 34 clams and 11,025 probes by means of an oligonucleotide microarray. We found distinct transcriptional patterns for each population based on a total of 553 differentially expressed genes (DEG), indicating innate differences which probably have a genetic basis. Race and latitude contributed significantly to gene expression differences, with very different sets of DEG. A gene ontology analysis showed that races differed mainly at genes involved in ribosomal function and protein biosynthesis, while genes related to glutathione metabolism and ATP synthesis in the mitochondria were the most outstanding as to north/south transcriptional differences.

genomics↗

bioRxiv2021

Phenotypic architecture of sociality and its associated genetic polymorphisms in zebrafish

Sociality is often seen as a single phenotypic trait, but it relies on motivational and cognitive components implemented by specific causal mechanisms. Hence, these components may have evolved independently, or may have been linked by phenotypic correlations driven by a shared selective pressure for increased social competence. Furthermore, these components may be domain-specific or of general domain across social and non-social contexts. Here we have characterized the phenotypic architecture of sociality in zebrafish, which has been increasingly used as a model organism in social neuroscience. For this purpose, we have behaviorally phenotyped zebrafish from different wild type lines in four tests: social tendency, social and non-social recognition, and open-field test. Our results indicate that: (1) sociality has two main components that are independent from each other (social tendency and social recognition), hence not supporting the occurrence of a sociality syndrome; (2) both social traits are phenotypically linked to non-social traits (non-social exploration and non-social memory, respectively), forming two general behavioral modules, general inspection and general recognition, and suggesting that sociality traits have been co-opted from general-domain motivational and cognitive traits. Moreover, the study of the association between genetic polymorphisms (i.e. single nucleotide polymorphisms, SNPs) and each behavioral module further supports this view, since several SNPs from a list of candidate "social" genes, are statistically associated with the general inspection (motivational), but not with a general recognition (cognitive), behavioral module. The SNPs associated with general inspection are widespread across different chromosomes and include neurotransmitters, neuromodulators, and synaptic plasticity genes, suggesting that this behavioral module is regulated by multiple genes, each of them with small effects. Together, these results support the occurrence of general domain motivational and cognitive behavioral modules in zebrafish, which have been co-opted for the social domain. Author summarySocial living has been considered one of the major transitions in evolution and it has been considered to act as a major selective force shaping the evolution of brain and behavior in animals. Sociality relies on two basic behavioral mechanisms: (1) the willingness to approach and be near others (aka social tendency); and (2) the ability to distinguish between others (aka social recognition) in order to adjust the behavior expressed during social interactions according to the identity of the interactant. There is an ongoing debate on to what extent these social abilities have specifically evolved in response to social living and are domain specific, or if they were selected as a broad response to cognitive demands and are of general domain. Here, we used zebrafish to test the domain-specific vs. general domain hypotheses and to assess the association of social tendency and social recognition with a set of candidate "social" genes (i.e. genes that have been linked to social behavior in other studies with different vertebrate species). We found that both social traits are not correlated to each other and are of general domain, and that only social tendency is associated with candidate "social" genes, suggesting that social tendency and social recognition are independent behavioral modules that rely on separate genetic architectures and that can evolve separately.

animal behavior and cognition↗

bioRxiv2021

Amino acids 484 and 494 of SARS-CoV-2 spike are hotspots of immune evasion affecting antibody but not ACE2 binding

Understanding SARS-CoV-2 evolution and host immunity is critical to control COVID-19 pandemics. At the core is an arms-race between SARS-CoV-2 antibody and angiotensin-converting enzyme 2 (ACE2) recognition, a function of the viral protein spike. Mutations in spike impacting antibody and/or ACE2 binding are appearing worldwide, with the effect of mutation synergy still incompletely understood. We engineered 25 spike-pseudotyped lentiviruses containing individual and combined mutations, and confirmed that E484K evades antibody neutralization elicited by infection or vaccination, a capacity augmented when complemented by K417N and N501Y mutations. In silico analysis provided an explanation for E484K immune evasion. E484 frequently engages in interactions with antibodies but not with ACE2. Importantly, we identified a novel amino acid of concern, S494, which shares a similar pattern. Using the already circulating mutation S494P, we found that it reduces antibody neutralization of convalescent and post-immunization sera, particularly when combined with E484K and N501Y. Our analysis of synergic mutations provides a landscape for hotspots for immune evasion and for targets for therapies, vaccines and diagnostics. One-Sentence SummaryAmino acids in SARS-CoV-2 spike protein implicated in immune evasion are biased for binding to neutralizing antibodies but dispensable for binding the host receptor angiotensin-converting enzyme

immunology↗

bioRxiv2018

Microbial diversity and toxin risk in tropical freshwater reservoirs of Cape Verde

The Cape Verde islands are part of the African Sahelian arid belt that possesses an irregular rainy season between August and October. This erratic rain pattern has prompted the need for water reservoirs, now critical for the countrys sustainability. Worldwide, freshwater cyanobacterial blooms are increasing in frequency due to global climate change and eutrophication of water bodies, particularly in reservoirs. To date there have been no risk assessments of cyanobacterial toxin production in these man-made structures. We evaluated this potential risk using 16S rRNA gene amplicon sequencing and full metagenome sequencing in freshwater reservoirs of Cape Verde.\n\nOur analysis revealed the presence of several potentially toxic cyanobacterial genera in all sampled reservoirs (Poilao, Saquinho and Faveta). In Faveta Microcystis sp., a genus well known for toxin production and bloom-formation, dominated our samples, while a green algae of the genus Cryptomonas and Gammaproteobacteria dominated Saquinho and Poilao.\n\nTaking advantage of the dominance of Microcystis in the Faveta reservoir, we were able to reconstruct and assemble its genome, extracted from a metagenome of bulk DNA from Faveta water. We named it Microcystis cf. aeruginosa CV01, for which a phylogenetic analysis revealed to have a close relationship with other genomes from those taxa, as well as other continental African strains, suggesting geographical coherency. In addition, it revealed several clusters of known toxin-producing genes. This assessment of Cape Verdean freshwater microbial diversity and potential for toxin production reinforces the need to better understand the microbial ecology as a whole of water reservoirs on the rise.

microbiology↗