Marine heatwaves drive recurrent mass mortalities in the Mediterranean Sea

Climate change is causing an increase in the frequency and intensity of marine heatwaves (MHWs) and mass mortality events (MMEs) of marine organisms are one of their main ecological impacts. Here, we show that during the 2015-2019 period, the Mediterranean Sea has experienced exceptional thermal conditions resulting in the onset of five consecutive years of widespread MMEs across the basin. These MMEs affected thousands of kilometers of coastline from the surface to 45 m, across a range of marine habitats and taxa (50 taxa across 8 phyla). Significant relationships were found between the incidence of MMEs and the heat exposure associated with MHWs observed both at the surface and across depths. Our findings reveal that the Mediterranean Sea is experiencing an acceleration of the ecological impacts of MHWs which poses an unprecedented threat to its ecosystems' health and functioning. Overall, we show that increasing the resolution of empirical observation is critical to enhancing our ability to more effectively understand and manage the consequences of climate change.

Transcriptomic and fatty acid analyses of Neochloris aquatica grown under different nitrogen concentration

In this study, we characterized the fatty acid production in Neochloris aquatica at transcriptomics and biochemical levels under limiting, normal, and excess nitrate concentrations in different growth phases. At the stationary phase, N. aquatica mainly produced saturated fatty acids such as stearic acid under the limiting nitrate concentration, which is suitable for biodiesel production. However, it produced polyunsaturated fatty acids such as α-linolenic acid under the excess nitrate concentration, which has nutritional values as food supplements. In addition, RNA-seq was employed to identify genes and pathways that were being affected in N. aquatica for three growth phases in the presence of the different nitrate amounts. Genes that are responsible for the production of saturated fatty acids were upregulated in the cells grown under a limiting nitrogen amount while genes that are responsible for the production of polyunsaturated fatty acid were upregulated in the cells grown under excess nitrogen amount. Further analysis showed more genes differentially expressed (DEGs) at the logarithmic phase in all conditions while a relatively steady trend was observed during the transition from the logarithmic phase to the stationary phase under limiting and excess nitrogen. Our results provide a foundation for identifying developmentally important genes and understanding the biological processes in the different growth phases of the N. aquatica in terms of biomass and lipid production.

Simple Identification of Mycobacterial Species by Sequence-Specific Multiple Polymerase Chain Reactions

Several species of mycobacteria cause infections in humans. Species identification of clinical isolates of mycobacteria is very important for the decision of treatment and in choosing the appropriate treatment regimen. We have developed a multiplex PCR method that can identify practically all known species of mycobacteria, by determination of single-nucleotide differences at a total of 13 different polymorphic regions in the genes of rRNA and hsp65, in four PCR mixes. To achieve this goal, single-nucleotide differences in these polymorphic regions were used to divide mycobacterial species into two groups, than four, eight, etc., in an algorithmic manner. It was sufficient to reach single species level by evaluating 13 polymorphic regions. Evaluation of the multiplex PCR patterns by observable real-time electrophoresis (ORTE) simplified species identification. This new method may enable easy, rapid, and cost-effective identification of all species of mycobacteria.