Factors influencing sexual cannibalism and its benefit to fecundity and offspring survival in the wolf spider Pardosa pseudoannulata (Araneae: Lycosidae)

Sexual cannibalism is hypothesized to have evolved as a way to obtain a high-quality meal, as an extreme mate choice or as a consequence of female aggressive spillover. Here, we examined underlying factors likely to influence sexual cannibalism in the wolf spider Pardosa pseudoannulata (Bösenberg & Strand, 1906) from China, including mating status, female egg-laid status, female hunger level, female adult age and mate size dimorphism. The results showed that about 10 % of P. pseudoannulata virgin females cannibalized the approaching males before mating and that 28 % of P. pseudoannulata virgin females immediately cannibalized the males after mating. No incidents of sexual cannibalism during copulation were observed. Before mating, previously mated females and starved females tended to engage in significantly higher rates of attacks compared to virgin and well-fed females. Females that had laid egg sacs tended to engage in a significantly higher rate of attacks and sexual cannibalism than virgin females before mating. Regardless of pre- or post-mating, there was a strong positive relationship between mate size dimorphism and the occurrence of sexual cannibalism. We also tested the effects of sexual cannibalism on the fecundity of cannibalistic females and the survival of their offspring. Our results indicated that sexual cannibalism affected positively the offspring survival of cannibalistic females, but not fecundity. Our findings support the hypothesis that sexual cannibalism has evolved as an adaptive component of female foraging strategy and that it benefits offspring survival as a result of paternal investment.     

Relationship between physicochemical properties and dewaterability of hydrothermal sludge derived from different source

Sewage sludge (SS) and deinking sludge (DS) were used to comparatively study the hydrothermal dewatering of sludge with different components. For a better overview, an insight into the relationship between physicochemical properties and dewaterability of hydrothermal sludge was provided. Results found that not all kinds of sludge were suitably conditioned by hydrothermal treatment (HT) in term of the elevation of dewaterability. Higher hydrothermal temperature tended to enhance the dewaterability of SS rather than DS, which was supported by the variation of their physicochemical properties (including water distribution, bonding energy, extracellular polymeric substance (EPS), particles size, acid functional groups and zeta potential in this study). In addition, the changes in surface morphology suggested that the reverse effect of HT on sludge dewaterability was mainly due to their dewatering behavior. For SS, the destruction of EPS structure leaded to the release of bound water, thereby strengthening sludge dewatering. Conversely, “Bridging effect” generated by lignocellulose in DS was beneficial for sludge dewatering; however, the increasing hydrothermal temperature degraded part of lignocellulose and weakened “bridging effect”, finally resulting in worse dewaterability of DS.     

Nitrogen budget and its environmental loading in an urban ecosystem with the rapid urbanisation of China

A detailed nitrogen (N) budget has been developed for an urban ecosystem based on the method of material flow analysis. How increased human activity and urbanisation influences N cycling have also been analysed. Total N input and output in the urban ecosystem of Zhengzhou City (ZUE) was calculated at 304.8?Gg was 275.3?Gg year^?1, resulting in an N accumulation of 29.5?Gg year^?1. Industry and human life activities, which respectively accounted for 43.8% and 34.2% of total N inputs and 52.6% and 29.1% of total N outputs, were the core of N flow in the urban ecosystem. Humans activities mediated more than 98% N inputs into the ZUE, 73.2% of N was released into the atmosphere and 11.7% into hydrosphere. This very large volume of released N could contribute to regional problems. High energy consumption, insufficient wastewater treatment facility practices, and low N use efficiency are the primary causes of pollution. The major challenge ahead for the urban ecosystem is how to manage high-intensity N pollutant inputs to the urban ecosystems coupled with incomplete N cycling and removal. Based on the analysis of the N budget and loading, this study also proposes an N management strategy for the ZUE.     

Toxicity of the pyrethroid bifenthrin insecticide

Bifenthrin is a chiral synthetic pyrethroid insecticide that has been commonly used for agricultural and domestic pest control over the past decades. Due to its widespread application, residues of bifenthrin has been frequently detected in environmental media, residential areas and biota, thus posing potential risks to the health of wildlife and humans. In particular, bifenthrin exhibits high acute lethal toxicity to aquatic species, and it is the primary contributor to the toxicity of insecticides in waters. Additionally, bifenthrin can also cause sublethal toxic effects on various non-target organisms, including developmental toxicity, neurobehavioral toxicity, oxidative damage, immune toxicity and endocrine disrupting effects. Here we review recent studies about the fate of bifenthrin in the environment and biological systems, the toxicity of the chiral parent compound bifenthrin and the toxic effects of main metabolites. The adverse effects of bifenthrin, identified from both in vitro and in vivo studies, and the potential underlying mechanisms are presented. We discuss the enantiomeric difference in the toxicological effects of bifenthrin, since enantiomers of chiral compounds show different interactions with biological systems. Pyrethroid insecticides metabolites are not acutely toxic, but they have sublethal toxicity, such as endocrine disrupting effects and immunotoxicity. We provide emerging evidence for toxic effects of several main metabolites.     

Roles of acid-producing bacteria in anaerobic digestion of waste activated sludge

Three acid-producing strains, AFB-1, AFB-2 and AFB-3, were isolated during this study, and their roles in anaerobic digestion of waste activated sludge (WAS) were evaluated. Data of 16S rRNA method showed that AFB-1 and AFB-2 were Bacillus coagulans, and AFB-3 was Escherichia coli. The removal in terms of volatile solids (VS) and total chemical oxygen demand (TCOD) was maximized at 42.7% and 44.7% by inoculating Bacillus coagulans AFB-1. Besides, the optimal inoculum concentration of Bacillus coagulans AFB-1 was 30% (v/v). Solubilization degree experiments indicated that solubilization ratios (SR) of WAS reached 20.8%±2.2%, 17.7%±1.48%, and 11.1%±1.53%. Volatile fatty acids (VFAs) concentrations and compositions were also explored with a gas chromatograph. The results showed that VFAs improved by 98.5%, 53.0% and 11.6% than those of the control, respectively. Biochemical methane potential (BMP) experiments revealed that biogas production increased by 90.7% and 75.3% when inoculating with Bacillus coagulans AFB-1 and AFB-2. These results confirmed that the isolated acid-producing bacteria, especially Bacillus coagulans, was a good candidate for anaerobic digestion of WAS.

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Historical trends of organochlorine pesticides (OCPs) recorded in sediments across the Tibetan Plateau

Sediment cores from four lakes across the Tibetan Plateau were used as natural archives to study the time trends of organochlorine pesticides (OCPs). The total concentrations of dichlorodiphenyltrichloroethane (ΣDDT) and hexachlorocyclohexane isomers (ΣHCH) were in the range of 0.04–1.61 and 0.08–1.88 ng/g based on dry weight (dw), while the input fluxes were in the range of 0.3–236 and 0.7–295 pg/cm²/y in the core sediments, respectively. The input fluxes of ΣDDT and ΣHCH generally peaked in sediment layers corresponding to the 1970s–1990s and peaked in top sediment layers. The ratio of α/γ-HCH decreased in the top layer sediments, implying that the contribution of lindane (pure γ-HCH) has been increasing in recent years. In addition, the ratio of o,p′-DDT/p,p′-DDT increased significantly over the last 15–20 years, suggesting that dicofol (characterized by high ratio of o,p′-DDT/p,p′-DDT about 7.0) has recently become a relatively more important source of DDT compared to technical DDT itself. The time trends of OCPs recorded in lake sediments examined the impact on such remote alpine regions by human activities.     

应用鱼类生物完整性指数评价荔浦河河流健康

生物完整性指数是河流生态系统健康评价主要方法之一。为评价荔浦河河流健康状况,选择鱼类作为指示生物,构建了基于鱼类生物完整性指标体系。2017年1月、4月、7月和10月对荔浦河4次采样共采集到鱼类21 192尾,经鉴定共计94种,隶属于6目17科62属。以S1(修仁镇)、S10(马岭镇)、S11(双江镇)作为参考点,经过分布范围分析、箱体图判别能力分析及相关性分析等指标筛选过程从25个候选指标筛选出5个指标,即鱼类总物种数、Shannon-Wiener多样性指数、肉食性鱼类数量百分比、敏感性鱼类数量百分比、产漂浮型卵鱼类数量百分比。将荔浦河河流健康等级分为"健康"、"一般"、"较差"、"极差"和"无鱼"5个等级。结果表明,荔浦河青山镇、荔浦县及蒲芦乡河段健康状态为"一般"水平,东昌镇、龙怀乡、杜莫镇及新坪镇河段健康状态为"较差"水平,茶城乡河段健康状态为"极差"水平。筑坝工程、架桥工程和修路工程等人类活动导致荔浦河支流上的健康状况比干流更差。上述研究结果可为荔浦河的河流管理和保护提供理论依据和技术支持。     

百草枯急性暴露对肝细胞L-O2的毒理研究

百草枯(paraquat,PQ)是目前农业生产上使用较为广泛的除草剂,PQ毒性极大,能造成人和动物多器官损伤。因肝脏是主要的受损器官之一,故以肝细胞L-O2为研究对象,探讨PQ急性暴露对肝细胞产生的毒理影响。结果显示在40!640μmol·L~(-1)暴露浓度下作用24 h,PQ显著抑制肝细胞L-O2的增殖活性(P0.01),半抑制浓度(IC50)为263.2μmol·L~(-1)。将肝细胞L-O2暴露于不同浓度的PQ(60、120、180和250μmol·L~(-1)),作用24 h后,与对照组相比,PQ暴露组的活性氧(ROS)累积和细胞凋亡率都表现出明显的浓度依赖性升高(P0.01; P0.05),细胞周期阻滞在S期。Western blot结果显示,除60μmol·L~(-1)外的其他暴露组中活化的胱天蛋白酶9(caspase-9)表达显著上调,Bax和Bcl-2的比值显著增大,提示细胞凋亡机制可能与内源性线粒体通路的激活有关。此外,碳酸酐酶9(CA9) mRNA表达显著升高,提示PQ暴露下可能引起酸性代谢产物出现,对细胞产生酸毒害,但其内在的机制还需进一步研究。     

Rapid dephosphorylation of glyphosate by Cu-catalyzed sulfite oxidation involving sulfate and hydroxyl radicals

Environmental Chemistry Letters - Glyphosate is a broad-spectrum toxic herbicide that has entered the environment. Advanced oxidation processes efficiently remove various persistent organic...     

Effects of different endogenous fungi on the mass loss and nutrient content of leaf litter of Cunninghamia lanceolata北大核心CSCD

To explore the role of endophytic fungi in the decomposition of litter, the endophytic fungi Penicillium sp. strain CG2 (A), Fusarium flavum strain AY13 (B), and Talaromyces strain AJ14 (C) of Cunninghamia lanceolata were added to experimental pots in different forms (mycelium, sterilized fermentation broth, single fungus, and mixed fungi), and a control treatment (CK) was set up (no fungi added). At 10, 30, 60, 90, and 120 days after litter decomposition, a study on the decomposition dynamics of C. lanceolata litter under different treatments was performed. The results showed that the rate of leaf mass loss was the highest in the sterilized fermentation broth treatment A after 120 days, and that there was a significant difference (P < 0.05) between the mycelium treatment AC and the control treatment after 60 days (23.97% higher than the control group). On day 60, the litter carbon content from the mycelium treatment A was significantly different from that of the control (P < 0.05), showing a 16.74% lower value, whereas the litter carbon content of the mycelium treatment B was 21.13% lower than that of the control after 90 days. The nitrogen content of the litters of most mycelium and sterilized fermentation broth treatments was increased compared to that of the control group; there was significant difference (P < 0.05) between the sterilized fermentation broth treatment A and the control (P < 0.05), with a 17.05% higher value than that of the control. Similar to nitrogen, the litter phosphorus content also increased; there was a statistically significant difference between the mycelium treatment A and the control group, with treatment A showing a 46.67% higher value than the control group. The potassium content was 28% lower than that of the control group under the sterilized fermentation broth treatment C, a result that was significantly different from that of the control group (P < 0.05). After treatment for 90 days, the ratio of carbon to nitrogen was the lowest under the treatments with the mycelium A and the mycelium B, with values 25.54% and 25.11% lower than that of the control group, respectively, and a statistically significant difference from that of the control group (P < 0.05). The ratio of carbon to phosphorus was the lowest under the treatment with mycelium A after 60 days, and the result was significantly different from that of the control (P < 0.05), with a 43.05% lower value than the control. Thus, the three endophytic fungi had different effects on the mass loss rate and nutrient content of the litter. The Penicillium sp. strain CG2 (A) had statistically significant effects on the mass loss and nutrient content of leaf litter, which was within the range of fungi fertilizer reference values for the breeding of C. lanceolata. © 2018 Science Press. All rights reserved.