Environmental Fluid Mechanics - Bed-load transport is a complex process exhibiting anomalous dynamics, which cannot be efficiently described using the traditional advection–diffusion... 相似文献
DNA宏条形码技术作为一种新型生物监测方法,在未来生态环境监测中有巨大的应用潜力。目前,浮游动物DNA宏条形码监测仍在发展阶段,需要首先对其(采样方法、引物选择和数据分析等)进行标准化和调整,然后才能用于常规流域生态监测。其中,如何选择合适的PCR扩增引物是DNA宏条形码生物监测标准化的关键问题之一。本研究比较了COI、18SV9和16S通用引物在浮游动物DNA宏条形码监测中的差异,为初步建立规范化的浮游动物DNA宏条形码监测方法提供技术支撑。结果表明,16S引物对浮游动物具有更好的特异性,其产生的操作分类单元(operational taxonomic unit, OTU)有88.1%属于浮游动物。虽然18SV9引物具有更高的物种覆盖度,不仅能扩增出浮游动物,还能扩增出大量藻类和真菌,但其物种识别敏感性较差,不适合浮游动物物种水平多样性监测。COI引物的浮游动物物种特异性、物种覆盖度和物种识别敏感性都适中,检出的浮游动物物种数量高于18SV9引物和16S引物,更加适合浮游动物DNA宏条形码监测。 相似文献
• Pig feces is the predominant excrement produced by animal husbandry in China.• The PF, Pig-1-BacTaqMan, and Pig-2-BacTaqMan MST assays showed better performance.• The pig-specific MST assays can contribute to managing the pig fecal pollution. In China, pig feces is the predominant source of excrement produced by animal husbandry. Improper use or direct discharge of pig feces can result in contamination of natural water systems. Microbial source tracking (MST) technology can identify the sources of fecal pollution in environmental water, and contribute to the management of pig fecal pollution by local environmental protection agencies. However, the accuracy of such assays can be context-dependent, and they have not been comprehensively evaluated under Chinese conditions. We aimed to compare the performance of five previously reported pig-specific MST assays (PF, Pig-Bac1SYBR, Pig-Bac2SYBR, Pig-1-BacTaqMan, and Pig-2-BacTaqMan, which are based on Bacteroidales 16S rRNA gene markers) and apply them in two rivers of North China. We collected a total of 173 fecal samples from pigs, cows, goats, chickens, humans, and horses across China. The PF assay optimized in this study showed outstanding qualitative performance and achieved 100% specificity and sensitivity. However, the two SYBR green qPCR assays (Pig-Bac1SYBR and Pig-Bac2SYBR) cross-reacted with most non-pig fecal samples. In contrast, both the Pig-1-BacTaqMan and Pig-2-BacTaqMan assays gave 100% specificity and sensitivity. Of these, the Pig-2-BacTaqMan assay showed higher reproducibility. Our results regarding the specificity of these pig-specific MST assays differ from those reported in Thailand, Japan, and America. Using the PF and Pig-2-BacTaqMan assays, a field test comparing the levels of pig fecal pollution in rivers near a pig farm before and after comprehensive environmental pollution governance indicated that pig fecal pollution was effectively controlled at this location. 相似文献
• Magnetotactic bacteria (MTB) synthesize magnetic nanoparticle within magnetosomes.• The morphologic and phylogenetic diversity of MTB were summarized.• Isolation and mass cultivation of MTB deserve extensive research for applications.• MTB can remove heavy metals, radionuclides, and organic pollutants from wastewater. Magnetotactic bacteria (MTB) are a group of Gram-negative prokaryotes that respond to the geomagnetic field. This unique property is attributed to the intracellular magnetosomes, which contains membrane-bound nanocrystals of magnetic iron minerals. This review summarizes the most recent advances in MTB, magnetosomes, and their potential applications especially the environmental pollutant control or remediation. The morphologic and phylogenetic diversity of MTB were first introduced, followed by a critical review of isolation and cultivation methods. Past research has devoted to optimize the factors, such as oxygen, carbon source, nitrogen source, nutrient broth, iron source, and mineral elements for the growth of MTB. Besides the applications of MTB in modern biological and medical fields, little attention was made on the environmental applications of MTB for wastewater treatment, which has been summarized in this review. For example, applications of MTB as adsorbents have resulted in a novel magnetic separation technology for removal of heavy metals or organic pollutants in wastewater. In addition, we summarized the current advance on pathogen removal and detection of endocrine disruptor which can inspire new insights toward sustainable engineering and practices. Finally, the new perspectives and possible directions for future studies are recommended, such as isolation of MTB, genetic modification of MTB for mass production and new environmental applications. The ultimate objective of this review is to promote the applications of MTB and magnetosomes in the environmental fields. 相似文献
• Published data was used to analyze the fate of ARGs in water treatment.• Biomass removal leads to the reduction in absolute abundance of ARGs.• Mechanism that filter biofilm maintain ARB/ARGs was summarized.• Potential BAR risks caused by biofiltration and chlorination were proposed. The bacterial antibiotic resistome (BAR) is one of the most serious contemporary medical challenges. The BAR problem in drinking water is receiving growing attention. In this study, we focused on the distribution, changes, and health risks of the BAR throughout the drinking water treatment system. We extracted the antibiotic resistance gene (ARG) data from recent publications and analyzed ARG profiles based on diversity, absolute abundance, and relative abundance. The absolute abundance of ARG was found to decrease with water treatment processes and was positively correlated with the abundance of 16S rRNA (r2 = 0.963, p<0.001), indicating that the reduction of ARG concentration was accompanied by decreasing biomass. Among treatment processes, biofiltration and chlorination were discovered to play important roles in shaping the bacterial antibiotic resistome. Chlorination exhibited positive effects in controlling the diversity of ARG, while biofiltration, especially granular activated carbon filtration, increased the diversity of ARG. Both biofiltration and chlorination altered the structure of the resistome by affecting relative ARG abundance. In addition, we analyzed the mechanism behind the impact of biofiltration and chlorination on the bacterial antibiotic resistome. By intercepting influent ARG-carrying bacteria, biofilters can enrich various ARGs and maintain ARGs in biofilm. Chlorination further selects bacteria co-resistant to chlorine and antibiotics. Finally, we proposed the BAR health risks caused by biofiltration and chlorination in water treatment. To reduce potential BAR risk in drinking water, membrane filtration technology and water boiling are recommended at the point of use. 相似文献