Metallothionein responses in the Asiatic clam (Corbicula fluminea) after exposure to trivalent arsenic

The main objective of this work was to evaluate arsenic effects on metallothionein (MT) induction by exposing a freshwater Asiatic clam (Corbicula fluminea) to different concentrations of this metalloid. The presence of MT-like proteins was detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis and compared with a standard rabbit MT. In addition, the polarographic response showed good correspondence between standard MT and MT-like curves from C. fluminea, allowing MT quantification. The results show that clams exposed to different concentrations of arsenic are able to induce significant levels of MTs. Although variability was found in MT induction, significant differences in MT levels were found after 28 days of exposure in all treatments in comparison with the controls, suggesting that exposure to arsenic induced MT-like proteins in C. fluminea.     

Using functional traits to investigate the determinants of crustacean zooplankton community structure

Understanding the various processes contributing to community assembly is among the central aims of ecology. As a means of exploring this topic we quantified the relative influences of habitat filtering and competition in establishing patterns of community functional trait diversity across a landscape of lakes. Habitat filtering has been invoked in shaping community structure when co‐occurring taxa are more similar in their traits than expected by chance (under‐dispersion), and competition has been inferred as a structuring agent when co‐occurring taxa are less similar (over‐dispersion). We tested these hypotheses in crustacean zooplankton communities using a functional trait‐based approach based on five traits defining zooplankton feeding and habitat preferences across 51 lakes spanning several large limnological gradients. In general, zooplankton communities were functionally less diverse than random assemblages created from the same regional species pool. Furthermore, functional diversity was strongly correlated with variables related to lake productivity, suggesting that access to resources was the chief habitat filtering process constraining zooplankton functional diversity. This pattern was driven by the predominantly herbivorous cladocerans as opposed to the more commonly omnivorous, and sometimes carnivorous, copepods.     

Genome-wide association mapping of sexual incompatibility genes in cacao (<Emphasis Type="Italic">Theobroma cacao</Emphasis> L.)

Sexual compatibility limits the production of cacao plantations, being an important selection criterion in breeding programs. However, the current method for characterizing compatibility, based on the frequency of flower setting after controlled pollination, is time consuming, requiring a long time to identify self-compatible individuals. The identification of molecular markers in genomic regions can be an alternative to allow early selection of self-compatible plants. The present study aimed to identify SNP markers associated with sexual compatibility in cacao, by utilizing genome-wide association (GWAS) mapping. A population of 295 individuals mostly from third-generation breeding populations, but also founder clones, was used. This population was phenotypically characterized by hand pollinating 8199 flowers and evaluating the flower retention 15 days after pollination. In addition, leaf samples of each individual were collected and DNA extracted for genotyping by sequencing, generating 5301 SNP markers after cleaning. Genome-wide association mapping analysis was performed using Synbreed, GCTA, and TASSEL softwares. Significant markers associated to incompatibility, likely in strong linkage disequilibrium, were found within a region of 196 kb, in the proximal end of chromosome 4, suggesting the existence of a major gene in that region. However, this result should be validated in a larger population, considering that only 295 trees were used here. When the SNP effects were treated as random in the estimation process, many other regions in the genome appears to be involved with sexual incompatibility in cacao. Candidate genes were found not only in the proximal end of chromosome 4 but also spread in several other regions of the genome.     

Phenotypic Features of Circulating Leukocytes from Non-human Primates Naturally Infected with Trypanosoma cruzi Resemble the Major Immunological Findings Observed in Human Chagas Disease

Background

Cynomolgus macaques (Macaca fascicularis) represent a feasible model for research on Chagas disease since natural T. cruzi infection in these primates leads to clinical outcomes similar to those observed in humans. However, it is still unknown whether these clinical similarities are accompanied by equivalent immunological characteristics in the two species. We have performed a detailed immunophenotypic analysis of circulating leukocytes together with systems biology approaches from 15 cynomolgus macaques naturally infected with T. cruzi (CH) presenting the chronic phase of Chagas disease to identify biomarkers that might be useful for clinical investigations.

Methods and Findings

Our data established that CH displayed increased expression of CD32⁺ and CD56⁺ in monocytes and enhanced frequency of NK Granzyme A⁺ cells as compared to non-infected controls (NI). Moreover, higher expression of CD54 and HLA-DR by T-cells, especially within the CD8⁺ subset, was the hallmark of CH. A high level of expression of Granzyme A and Perforin underscored the enhanced cytotoxicity-linked pattern of CD8⁺ T-lymphocytes from CH. Increased frequency of B-cells with up-regulated expression of Fc-γRII was also observed in CH. Complex and imbricate biomarker networks demonstrated that CH showed a shift towards cross-talk among cells of the adaptive immune system. Systems biology analysis further established monocytes and NK-cell phenotypes and the T-cell activation status, along with the Granzyme A expression by CD8⁺ T-cells, as the most reliable biomarkers of potential use for clinical applications.

Conclusions

Altogether, these findings demonstrated that the similarities in phenotypic features of circulating leukocytes observed in cynomolgus macaques and humans infected with T. cruzi further supports the use of these monkeys in preclinical toxicology and pharmacology studies applied to development and testing of new drugs for Chagas disease.     

“One Health” or Three? Publication Silos Among the One Health Disciplines

The One Health initiative is a global effort fostering interdisciplinary collaborations to address challenges in human, animal, and environmental health. While One Health has received considerable press, its benefits remain unclear because its effects have not been quantitatively described. We systematically surveyed the published literature and used social network analysis to measure interdisciplinarity in One Health studies constructing dynamic pathogen transmission models. The number of publications fulfilling our search criteria increased by 14.6% per year, which is faster than growth rates for life sciences as a whole and for most biology subdisciplines. Surveyed publications clustered into three communities: one used by ecologists, one used by veterinarians, and a third diverse-authorship community used by population biologists, mathematicians, epidemiologists, and experts in human health. Overlap between these communities increased through time in terms of author number, diversity of co-author affiliations, and diversity of citations. However, communities continue to differ in the systems studied, questions asked, and methods employed. While the infectious disease research community has made significant progress toward integrating its participating disciplines, some segregation—especially along the veterinary/ecological research interface—remains.     

Fraying around the edges: negative effects of the invasive Tradescantia zebrina Hort. ex Bosse (Commelinaceae) on tree regeneration in the Atlantic Forest under different competitive and environmental conditions

Aims Invasive plants modify the structure and functioning of natural environments and threat native plant communities. Invasive species are often favored by human interference such as the creation of artificial forest edges. Field removal experiments may clarify if invasive plants are detrimental to native plant regeneration and how this is related to other local factors. We assessed the joint effect of environment and competition with the invasiveTradescantia zebrinaon tree species recruitment in an Atlantic Forest fragment.