The mud crab Scylla serrata is an important commercial crustacean being widely distributed along the southeastern coast of China. This crab and particularly
its gills are subjected to seasonal fluctuations of environmental factors due to direct exposure to seawater. The investigation
of seasonal variations of ATPase and antioxidant defenses in gills could be helpful for the understanding of physiological
regulation mechanism of seasonal adaptations. In this study, mud crabs were collected from the subtropical waters near Xiamen
island, Southeast China (24°26′46′′N, 118°04′04′′E), in August and November, 2002, and February and May, 2003, respectively,
being considered as specimens from summer, autumn, winter and spring, respectively. Only healthy intermoult male crabs without
carapace or appendage damage were used, having a carapace width of 7.05 ± 0.52 cm and a wet weight of 130 ± 20 g. The activities
of four ATPases and three antioxidation enzymes (superoxide dismutase, catalase, glutathione peroxidase) and the content of
malondialdehyde in gills were measured. The results showed that the activities of Na+, K+-ATPase, Mg2+-ATPase, Ca2+-ATPase and Ca2+, Mg2+-ATPase reached maximum levels similarly in summer and decreased in winter. The activities of superoxide dismutase and catalase
were higher in summer and lower in winter, with a significant decrease in winter compared to the other seasons (p < 0.01). Glutathione peroxidase activity was higher in summer, and lower in autumn, being significantly higher in summer or
winter than in spring or autumn (p < 0.01). Malondialdehyde content was higher in summer and lower in spring with significant differences among the different
seasons (p < 0.01). In summary, the obvious seasonal activity variations of four ATPases and antioxidant enzymes and the content of malondialdehyde
reflect a seasonal regulation of the physiological metabolising enzyme and the antioxidant capacity to cope with seasonal
alterations of environment factors such as fluctuating salinities and temperatures. 相似文献
Environmental Science and Pollution Research - Since the millennium, China has economically taken off with rapid urbanization, and anthropogenic nitrogen emission intensity has undergone remarkable... 相似文献
• Explaintheadsorption, uptake and transmembrane transport of PAHs by bacteria.• Analyze functional regulation of membrane proteins inthe transmembrane transport.• Proteomics technology such as iTRAQ labeling was used to access expressed proteins.• Single cell analysis technology wereused to study the morphological structure. In recent years, increasing research has been conducted on transmembrane transport processes and the mechanisms behind the microbial breakdown of polycyclic aromatic hydrocarbons (PAHs), including the role of membrane proteins in transmembrane transport and the mode of transmission. This article explains the adsorption, uptake and transmembrane transport of PAHs by bacteria, the regulation of membrane protein function during the transmembrane transport. There are three different regulation mechanisms for uptake, depending on the state and size of the oil droplets relative to the size of the microbial cells, which are (i) direct adhesion, (ii) emulsification and pseudosolubilization, and (iii) interfacial uptake. Furthermore, two main transmembrane transport modes are introduced, which are (i) active transport and (ii) passive uptake and active efflux mechanism. Meanwhile, introduce the proteomics and single cell analysis technology used to address these areas of research, such as Isobaric tags for relative and absolute quantitation (iTRAQ) technology and Nano Secondary ion mass spectrometry (Nano-SIMS). Additionally, analyze the changes in morphology and structure and the characteristics of microbial cell membranes in the process of transmembrane transport. Finally, recognize the microscopic mechanism of PAHs biodegradation in terms of cell and membrane proteins are of great theoretical and practical significance for understanding the factors that influence the efficient degradation of PAHs contaminants in soil and for remediating the PAHs contamination in this area with biotechnology. 相似文献
Clogging is the most significant challenge limiting the application of constructed wetlands. Application of a forced resting period is a practical way to relieve clogging, particularly bioclogging. To reveal the alleviation mechanisms behind such a resting operation, evapotranspiration and oxygen flux were studied during a resting period in a laboratory vertical-flow constructed wetland model through physical simulation and numerical model analysis. In addition, the optimum theoretical resting duration was determined based on the time required for oxygen to completely fill the pores, i.e., formation of a sufficiently thick and completely dry layer. The results indicated that (1) evapotranspiration was not the key factor, but was a driving force in the alleviation of bioclogging; (2) the rate of oxygen diffusion into the pores was sufficient to oxidize and disperse the flocculant biofilm, which was essential to alleviate bioclogging. This study provides important insights into understanding how clogging/bioclogging can be alleviated in vertical-flow constructed wetlands.
This study is the first report describing the occurrence of 15 phthalate acid esters (PAEs) in the three typical water sources of YiXing City, Taihu Upper-River Basin, East China. The fate of target PAEs in the Jiubin drinking water treatment plant (JTP) was also analyzed. The amounts of Σ15PAE in the Hengshan (HS), Youche (YC), and Xijiu (XJ) water sources were relatively moderate, with mean values of 360, 357, and 697 ng L−1, respectively. Bis(2-ethylhexyl) phthalate (DEHP) dominated the PAE concentration, making up 80% of the 15 total PAEs. The highest levels of Σ15PAE were found in HS, YC, and XJ in March 2015, January 2015, and July 2014, respectively. The occurrence and concentrations of these compounds were spatially dependent, and the mean concentrations of Σ15PAE in HS, YC, and XJ samples increased from the surface layer to the bottom layer with varied percentage increases. The removal efficiency of the PAEs in the finished water varied markedly, and the removal of PAEs by the JTP ranged from 12.8 to 64.5%. The potential ecosystem risk assessment indicated that the risk of PAEs was relatively low in these three water sources. However, risks posed by PAEs due to drinking water still exist; therefore, special attention should be paid to source control in the JTP, and advanced treatment processes for drinking water supplies should be implemented.