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Microcystis aeruginosa is the most common species responsible for toxic cyanobacterial blooms and is considered a significant contributor to the production of cyanotoxins, particularly the potent liver toxins called microcystins. Numerous studies investigating Microcystis spp. blooms have revealed their deleterious effects in freshwater environments. However, the available knowledge regarding the global phosphoproteomics of M. aeruginosa and their regulatory roles in toxin generation is limited. In this study, we conducted comparative phosphoproteomic profiling of non-toxic and toxin-producing strains of M. aeruginosa. We identified 59 phosphorylation sites in 37 proteins in a non-toxic strain and 26 phosphorylation sites in 18 proteins in a toxin-producing strain. The analysis of protein phosphorylation abundances and functions in redox homeostasis, energy metabolism, light absorption and photosynthesis showed marked differences between the non-toxic and toxin-producing strains of M. aeruginosa, indicating that these processes are strongly related to toxin generation. Moreover, the protein-protein interaction results indicated that BJ0JVG8 can directly interact with the PemK-like toxin protein B0JQN8. Thus, the phosphorylation of B0JQN8 appears to be associated with the regulatory roles of toxins in physiological activity.

Abstract:The South-to-North Water Diversion Project (SNWDP) is the largest water transfer project in the world, and its purpose is to relax water constraints in a region facing severe water scarcity. Bacterial communities from these reservoirs are important to human health, and analyzing their diversity and structure is crucial to water safety. Here, we investigated the dynamics of bacterial communities and their relationship with environmental parameters in the terminal reservoir (Miyun Reservoir) of the Middle Route of the SNWDP by high-throughput sequencing technology. Our results showed that Firmicutes, Proteobacteria, Cyanobacteria and Bacterioidetes were the most abundant phyla in the water column, and the community composition fluctuated seasonally. Moreover, the detected diversity of the bacterial community composition provided novel insights into the ongoing biogeochemical processes. The temperature was positively correlated with the dominant bacteria, with other factors, including the total dissolved solids, total phosphorus, dissolved oxygen and total nitrogen, shaping the structure and distribution of the microbial community. Furthermore, the metagenome showed broad phylogenetic diversity, indicating that organisms were involved in multiple essential environmental processes. This work is important for building a database to understand how microbial communities change after water transfers.

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Multivariate statistical methods, such as cluster analysis (CA), discriminant analysis (DA), and factor analysis (FA) were applied to the data on water quality of Lake Taoranting (Beijing), generated during two years (2011-2012), with monitoring at five different sites. The CA grouped the eight months (March to November) into three periods，and classified five sites into two clusters based on water quality characteristics. The DA showed the best results for data reduction and temporal analysis. It calculated six parameters (TEMP，pH，SD，CODMn，TSS and Chl-a) were the major sources of temporal variations in water quality. The FA applied to datasets of two special clusters of the lake calculated three factors for each region, capturing 72.89% and 78.88% of the total variance, respectively. Factors obtained from FA indicate that some parameters such as Chl-a, TSS, TP and NH4 +-N are mainly key factors responsible for water quality. Thus, this study results suggested that multivariate statistical methods is a effective tool for analysis of urban landscape water quality

Abstract-At present, the occurrence of harmful algal bloom has become a serious environmental problem in China. A survey of the seasonal variations of algal bloom characteristics has been investigated in a shallow hypertrophic urban lake from June to October 2013 in this study. LC-MS results indicated that there are two main cyanobacteria toxins variants (MC-LR and MC-RR) during harmful algal blooms. The community structure of cyanobacteria showed that 81.04 % of total cyanobacteria biomass belongs to Microcystis spp. and the average biomass of Microcystis spp. was 2.335 mg·L -1 . In addition, multivariate analyses by principal component and classifying analysis (PCCA) suggest that microcystins were mainly produced by Microcystis spp. and TP could promote MC production.

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