Metal-macrofauna interactions determine microbial community structure and function in copper contaminated sediments

Peer reviewedPublisher PD

Pathogenic marine microbes influence the effects of climate change on a commercially important tropical bivalve

There is growing evidence that climate change will increase the prevalence of toxic algae and harmful bacteria, which can accumulate in marine bivalves. However, we know little about any possible interactions between exposure to these microorganisms and the effects of climate change on bivalve health, or about how this may affect the bivalve toxin-pathogen load. In mesocosm experiments, mussels, Perna viridis, were subjected to simulated climate change (warming and/or hyposalinity) and exposed to harmful bacteria and/or toxin-producing dinoflagellates. We found significant interactions between climate change and these microbes on metabolic and/or immunobiological function and toxin-pathogen load in mussels. Surprisingly, however, these effects were virtually eliminated when mussels were exposed to both harmful microorganisms simultaneously. This study is the first to examine the effects of climate change on determining mussel toxin-pathogen load in an ecologically relevant, multi-trophic context. The results may have considerable implications for seafood safety

Natural Variation of Model Mutant Phenotypes in Ciona intestinalis

BACKGROUND: The study of ascidians (Chordata, Tunicata) has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. CONCLUSIONS/SIGNIFICANCE: Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity

Os acordos-marco internacionais e as alianças sindicais internacionais: instrumentos de uma necessária transnacionalização da militância sindical

Diante da multiplicação atual dos instrumentos de responsabilidade social empresarial (RSE), o dispositivo frequentemente considerado mais avançado em matéria de defesa dos direitos dos trabalhadores consiste na negociação e na assinatura de acordos-marco internacionais (AMIs). Esses acordos, assinados conjuntamente por uma federação sindical internacional e pela direção de uma empresa multinacional, buscam garantir o reconhecimento de certos direitos sociais fundamentais em todas as operações de uma empresa em âmbito internacional. Baseado na análise dos casos de duas empresas norte-americanas que ratificaram AMIs, este artigo procura evidenciar a contribuição desse instrumento para a regulação social das multinacionais e esclarecer as condições de sua efetividade, assim como seus limites. Ambos os casos demonstram que a utilidade desses acordos repousa, acima de tudo, no modo como os atores sindicais se apropriam desse instrumento. Por fim, nosso estudo salienta a importância das alianças ou coalizões internacionais entre os representantes sindicais de uma mesma multinacional para acompanhar os acordos e lhes dar um sentido prático em sua realidade local