Effects of pollution on macroinvertebrates and water quality bio-assessment

Many large rivers in China have an inflow of contaminated water. Water pollution caused by urban sewage and agriculture, and occasionally pollution events from industries have become a significant stress on aquatic ecology. Pollution affects the biodiversity of the aquatic community and the species composition changes from natural species to tolerant species. The species composition of aquatic animals may reflect water pollution level. Extremely non-uniform distributions of functional feeding groups occurred as a result of high nutrient levels. A combination of chemical and biological methods constitutes the best approach for biological monitoring studies that measure water quality. Macroinvertebrates were used as bio-assessment indicator to determine the environmental quality of given water body. In this study, samples of water and macroinvertebrates were taken from several dozen sites in 14 rivers in China with different pollution levels, including the Yangtze, East, Weihe, Songhua, Yongding, and Panlong rivers. Macroinvertebrates were identified to genus or family level. Water samples were classified into different water quality grades according to the concentration of different substances. Five biological indices: taxa richness (S), density (D), total BMWQ score (t-BMWQ), average BMWQ score (a-BMWQ), and the family biotic index (FBI) were used for biological assessment of water quality. Analyzing macroinvertebrates’ occurrence in different water quality levels, taxa-specific indicators, which are defined as the taxa of macroinvertebrates that live in a certain water quality level but do not exist in other water quality levels were proposed for water quality bio-assessment. Leptophlebiidae, Siphlonuridae, Arctopsychidae, Perlidae, and Antocha sp. are the taxa-specific indicators for very good or good water quality; Chironomidae, Lymnaeidae, Tubifex sp., Limnodrilus sp., Limnoperna lacustris, Corbicula sp., Macrobrachium sp., Planorbidae, Glossiphoniidae, and Branchiura sp. are the taxa-specific indicators for very poor water quality; and Psychomyiidae and Hydroptilidae are the taxa-specific indicators for moderate water quality.     

Expression of toll-like receptor 4 is down-regulated during progression of cervical neoplasia

Chronic infection and inflammation are among the most important factors contributing to cancer development and growth. Toll-like receptors (TLRs) are important families of pattern recognition receptors, which recognize conserved components of microbes and trigger the immune response against invading microorganisms. TLR4 is the signaling receptor for lipopolysaccharide (LPS), the endotoxic component of Gram-negative bacteria. Recent studies demonstrate that TLRs are expressed in some tumor cells, and that the expression of TLRs in these cells is associated with tumorigenesis. Cervical intraepithelial neoplasia (CIN) is a key stage in the development of cervical cancer and human papillomavirus (HPV) infection is an essential factor in cervical carcinogenesis. As the cervix is in constant contact with bacteria, especially Gram-negative bacteria, we hypothesize that TLR4-mediated bacterial stimulation may be involved in the tumorigenesis of cervical cancer. In the present study, the expression and distribution of TLR4 in CIN and cervical squamous carcinoma were investigated by immunohistochemistry. To our surprise, we observed a decrease in the expression of TLR4 during the progression of cervical neoplasia and this down-regulation of TLR4 appeared to be associated with the expression of \textP ^{1 6\textINK4A} , {\text{P}}^{{ 1 6^{\text{INK4A}} }} , which is a crucial marker of HPV integration into host cells. These data offer further insight regarding the association of HPV infection and TLR signaling during the carcinogenesis of cervical cancer.     

Seasonal and interannual variations of ecosystem photosynthetic characteristics in a semi-arid grassland of Northern China

北方半干旱草原生态系统光合参数的季节和年际变异 生态系统表观量子效率(α)、最大光合速率(P_max)和暗呼吸速率(R_d)不仅反映了生态系统水平 光合生理特征,同时也是碳循环模型中光合过程模拟的关键参数。气候和植被因子都会影 响光合参数的季节和年际变异,但二者在光合参数调控过程中的相对贡献和作用途径尚不清晰。本研究基于连续12年(2006–2017)的涡度相关观测数据,分析了内蒙古半干旱典型草原光合参数的季节和年际变化规律;利用回归分析和结构方程模型(SEM)方法明晰了环境和生理调控的作用途径及相对贡献。结果发现,光合参数(α、P_max和R_d)均表现出单峰的季节变化趋势,并呈现明显的年际波动。温度(T_a)和土壤含水量(SWC)的变化共同影响光合参数的季节变化,而SWC主导了其年际变异。α和R_d的变化主要由T_a决定,而Pmax的变化主要受SWC的影响。SEM模型分析表明,除了直接作用外,环境因子主要通过影响冠层水平气孔导度(gc)对光合参数和碳同化生理过程进行调控。此外,叶面积指数对光合参数特别是Pmax的季节和年际变异起主要调控作用。以上结果明确了环境和植被共同决定了生态系统水平光合参数的季节和年际变异,并强调了在水分受限的草原生态系统中,植被生理调控在光合碳同化能力和碳汇功能评估中的重要作用。     

木论喀斯特常绿落叶阔叶林木本植物萌生特征

萌生更新是植物进行自我更新的重要方式之一。为了阐明喀斯特常绿落叶阔叶林植物的萌生特征,基于木论25 hm²动态监测样地的调查数据,分析了木本植物萌生更新数量特征、不同生活型植物萌生能力的差异、萌生能力与地形因子和萌生能力与物种多样性的关系。研究结果表明：样地具有萌生现象的木本植物共有197种,隶属59个科137个属,分别占样地植物科属种的86.8%、93.7%、91.3%。萌生现象在样地内各物种中普遍存在,滇丁香、长管越南茜、火棘、香叶树等物种的萌生能力较强。不同生活型的植物的萌生能力存在显著差异,常绿树种的萌生能力显著高于落叶树种（P<0.001）。萌生物种丰富度比例及萌生物种个体比例都与群落物种多样性呈显著正相关。萌生能力与土层厚度呈显著负相关,与凹凸度呈显著正相关,此外萌生物种丰富度比例还与海拔呈正相关关系,而萌生物种个体比例与岩石出露率和土壤坡度呈正相关关系。由此可见,作为喀斯特森林群落更新中一种占优势的更新方式,萌生更新在一定程度上能够增加群落物种多样性,萌生能力与地形因子存在一定关联。     

Survival and attachment of biofouling freshwater mussel (Limnoperna fortunei) to environmental conditions: potential implications in its invasion,infection and biofouling control

Limnology - The golden mussel (Limnoperna fortunei) has caused worldwide problems for the eco-environment and man-made structures. There have been many control strategies proposed, which have...     

Comprehensive Insight into the Structure Contribution of A2-A1-D-A1-A2 Acceptor to Performance of P3HT Solar Cells

Poly(3-hexylthiophene) (P3HT) acting as one of the most popular and low-cost polymers is quite suitable for commercialization of organic solar cells but suffers from low power conversion efficiency (PCE) because of the limited matching non-fullerene acceptors (NFAs). One important reason that restricts the enhancement but remains unresolved is the undisclosed contributions of the subtle structure modification to the obvious performance change. In combination with the previous reports and this work, herein A₂-A₁-D-A₁-A₂ type NFAs with single, dual, and triple modifications based on parent BTA3 is designed, including benzyl-substitution on A₂ group (namely Bn modification), fluorine-substitution on A₁ group (namely F modification), and thieno[3,2-b]thiophene-substitution on D group (namely TT modification). It is finally found that the binary devices of P3HT with these NFAs underwent unexpected variations in the aspect of molecular optoelectronic property, blend morphological feature and charge generation process. The triple modification (including Bn, F, and TT) gives full play to their unique advantages and consequently increases PCE by 60%. To the knowledge, the obtained optimal PCE is one of the highest values for A₂-A₁-D-A₁-A₂ type NFAs. This study provides clearer insights into the rational substitutions on the A₂-A₁-D-A₁-A₂ acceptors matched with P3HT for high-performance organic photovoltaics.     

Astragaloside IV ameliorates fat metabolism in the liver of ageing mice through targeting mitochondrial activity

Astragaloside IV (AST) is a major bioactive compound of Radix Astragali with medical and health benefits. Previous studies have found that AST can reduce the body weights of high-fat diet fed mice. However, the effect of AST on fat metabolism of ageing mice is unclear. In this study, naturally ageing mice were administered intragastrically with AST at 30 mg/kg/day (ageing + AST-L group) and 90 mg/kg/day (ageing + AST-H group) for 16–20 months. Adult (4 months old) and ageing mice were given 1% sodium carboxyl methylcellulose as vehicle. Energy metabolism-related biological parameters of living mice were examined. Moreover, mRNA and protein levels of key enzymes/proteins involved in triglyceride (TG) lipolysis, fatty acid β-oxidation (FAO), ketone body (KB) production and mitochondrial respiratory chain were also examined after sacrifice. Results demonstrated that treatment with AST significantly reduced body weight, white fat and liver/body weight ratio of ageing mice, significantly reduced serum/hepatic TG levels, respiratory quotient, promoted fatty acid mobilization in white adipose tissue, mitochondrial FAO and KB production and mitochondrial biosynthesis/functions in the liver of ageing mice. AST also up-regulated the expression of phosphorylated AMP-activated protein kinase, acetyl-CoA carboxylase, acetyl-coenzyme A synthetase, carnitine palmitoyltransferase 1a/1b, enoyl coenzyme A hydratase-short chain, acyl-CoA dehydrogenase medium chain and mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase-2 involved in fat metabolism. These results indicated that mitochondrial activity could be the target of AST to treat abnormal fat metabolism during ageing.