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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Biofilter is the core unit of the recirculating aquaculture system(RAS), which is mainly to achieve in situ purification and restoration of water pollutants by enriching microorganisms on biofilters to form biofilms. To explore the changes and metabolic characteristics of microbial communities in the process of biofilm formation in the RAS under low-temperature environment, the 16S rRNA high-throughput sequencing was applied to analyze differences of the microbial composition and structural characteristics in the biofilm initiation group (I) and biofilm formation group(B), and the PICRUSt functional gene prediction method was used to predict the metabolic functions. Results of microbial diversity showed that the OTUs numbers, Shannon index and richness index increased significantly after bio-film formation(p<0.05). The Pcoa results indicated that the microbial community composition in group B was quite different compared with the group I. After the biofilm formation, the phylum Proteobacteria, Bacteroidota, Fusobacteriota, Patescibacteria and Verrucomicrobiota were the main dominant bacteria on the biofilter. The denitrifying bacteria, such as Comamonadaceae and Rhodobacteraceae as the dominant bacteria in group B. Meanwhile, the activities of bio-film microorganisms in metabolic aspects of Carbohydrate Metabolism, Energy Metabolism, Lipid Metabolism, Amino Acid Metabolism of Terpenoids and Polyketides and Enzyme Families were obviously enhanced(p <0.05).

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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-This paper represents to propose an effective extraction procedure for traditional toxin determination techniques in urban lake. Efficiency of each extraction solvent as well as other key parameters affecting extraction efficiency including ultrasonication time and extraction pH were evaluated and optimized. The present study results indicated that 40% acidified methanol (pH~3) with sonication 15~20min has been shown to be a rapid and efficient method for the routine analysis of a wide range of microcystins in water samples. Our study also suggested that analytical method based on HPLC-MS/MS with SPE techniques provides a simplified enrichment procedure and rich information for both quantization and identification effective tool for analysis of urban landscape water quality. The development of this method may facilitate the understanding of the best extraction method for the routine analysis of microcystins in water bodies. Moreover, it may be valuable for purification scale. Index Terms-Microcystin, extraction, HPLC-MS/MS, urban landscape water. I. INTRODUCTIONUrban landscape water in China are very often man-made ecosystem. They are very small and shallow. As an essential part of urban ecosystem, urban lake also play an important role in promoting socio-economic development, by regulating climate and providing a good place for recreational [1]- [2]. With increasing anthropogenic activities and excessive inputs of nitrogen and phosphorus to water environments, urban lake waters quality are extremely deteriorated in recent years. As a consequence, the appearance of Cyanobacteria (blue-green algae) can produce microsytins, frequently breakout in highly eutrophication lakes. It is considered to be an important water quality problem, implicating that a serious health problem in water supplies, both for livestock and human health [3]-[5].Microcystin is the most commonly synthesized toxin produced by toxin producing cyanobacteria species of Currently, there is a lack of understanding toxicology and risk assessment of urban lake Cyanobacterial toxins. For deeply study urban lake microcystins during algal blooms, optimization of extraction were conducted by HPLC-MS/MS approaches in our study for determination of microcystins from urban lake samples. II. MATERIALS AND METHODS A. ChemicalsAll the chemicals include HPLC-S grade acetonitrile, HPLC grade methanol and Trifluoroacetic acid (TFA) were purchased from Beijing Chemicals Ltd. Ultra-pure water was prepared on a Milli-Q Synthesis system (Millipore, France). microcystin LR, RR standards were bought from Beijing express Company. Sep-pak ODS cartridge (1000g, 12ml) was manufactured by Tianjin Alega Technologies. B. Sample Preparation for Microcystins ExtractionBefore the HPLC analyses, all water samples (1 L) were filtered on GF/C filters. Commercially available SPE fibers were purchased from Alega. Each fiber was eluted by 20ml methanol and pure water 20ml separately before extraction. To carry out the SPE extraction, water samples were extracted under diff...

Abstract-In present study, we are intrested in establishing a biological removal method by microorganism against the cyanobacterial hepatotoxin microcystion. A native microcystindegrading bacterium was isolated from a shallow hypertrophic lake, and the biodegradation effect was detected by the LC-MS method. The 16S rDNA gene sequence analysis result indicated that the isolated strain T11 was belonged to the genus Arthrobacter sp., with a highest sequence similarity (98%) with Arthrobacter sp. C6 strain. LC-MS result showed that the Arthrobacter sp. T11 was able to effectively degrade, at a highest concentration of MC (MC-LR ~ 15μg·L -1 ; MC-RR ~ 20μg·L -1 ) in batch experiments using sterilized lake water conditions, with complete removal observed within 10 days.