Project description:Atrazine is one of the most commonly used herbicide and has been frequently detected in estuarine and offshore waters worldwide. As a photosystem Ⅱ inhibitor, atrazine may inhibit phytoplankton from fixating of CO2 and alter its carbon metabolism, which will undoubtedly have negative effect on the primary productivity and carbon sequestration capacity of coastal waters. However, the existing reports mainly focused on agriculture and freshwater ecosystems and are mostly toxicity test with high-dose of atrazine, which have little concern about the negative effects of atrazine on the carbon metabolism of phytoplankton and can’t reflect the actual toxic situation in offshore water. Diatoms are widely distributed in freshwater and oceans and contribute at least 20% of the global CO2 assimilation, which is an ideal model group to assess the ecological risk of atrazine. Here we present a comprehensive analysis of the physiological and genome-wide gene expression characteristics of the diatom P. tricornutum Pt-1 (CCMP 2561) treated with environmental dose of atrazine at different stress stages.
Project description:Marine cyanobacteria are thought to be the most sensitive of the phytoplankton groups to copper toxicity, yet little is known of the transcriptional response of marine Synechococcus to copper shock. Global transcriptional response to two levels of copper shock was assayed in both a coastal and an open ocean strain of marine Synechococcus using whole genome expression microarrays. Both strains showed an osmoregulatory-like response, perhaps as a result of increasing membrane permeability. This could have implications for marine carbon cycling if copper shock leads to dissolved organic carbon leakage in Synechococcus. The two strains additionally showed a reduction in photosynthetic gene transcripts. Contrastingly, the open ocean strain showed a typical stress response whereas the coastal strain exhibited a more specific oxidative or heavy metal type response. In addition, the coastal strain activated more regulatory elements and transporters, many of which are not conserved in other marine Synechococcus strains and may have been acquired by horizontal gene transfer. Thus, tolerance to copper shock in some marine Synechococcus may in part be a result of an increased ability to sense and respond in a more specialized manner.
Project description:Illumina Sequencing Reveals High Diversity and Succession of Nanoplankton Community During the Brown Tide on the Changli Coast, China
