两株微生物絮凝剂产生菌的絮凝条件优化及鉴定

以絮凝菌A9和BS-5及其产生的絮凝剂为研究对象,通过改变碳源、氮源及初始pH值等因素研究絮凝菌的适宜培养条件,采用紫外扫描、Molish、蒽酮呈色反应和红外光谱等方法对这两种絮凝剂的成分进行检测,采用分子生物学等方法对菌株A9和BS-5进行菌种鉴定.结果表明,菌株A9和BS-5产生絮凝剂的适宜碳源均为可溶性淀粉,适宜氮源分别为酵母膏和NaNO3,适宜初始pH值分别为9.0和6.0,在此条件下产生的絮凝剂的絮凝率均达到95％以上.紫外扫描和红外检测等结果表明,菌株A9所产絮凝剂的主要成分为多糖类物质,菌株BS-5所产絮凝剂的主要成分为多糖类物质和少量蛋白质.系统发育树分析结果表明,絮凝菌A9属于类芽孢杆菌(Paenibacillus sp.),絮凝菌BS-5属于代尔夫特食酸菌(Delftia acidovorans).     

镉对鲫鱼鳃和肝脏超氧化物歧化酶活性的影响

使用浸浴法以 0 mg/ L、0 .73 mg/ L、1 .46 mg/ L、2 .95 mg/ L 4个镉 (Cd Cl2 · 2 .5H2 O)浓度为丰产鲫 (Carassiusauratus of Penze(♀ )× Cyprinusacutidorsalis(♂ ) )幼鱼染毒 ,测定了 1 4 4 h内鳃及肝组织中超氧化物歧化酶 (SOD)活性的变化。结果表明 ,低浓度组Cd曝露时 ,鲫鱼鳃和肝组织中 SOD活性的变化短时间内不明显 ,但随着处理时间的延长 ,Cd提高了鳃和肝组织中 SOD的活性 ,导致“毒物兴奋效应”。高浓度组 Cd曝露时均抑制了肝和鳃中的 SOD活性 ,其作用随着曝露时间的延长和浓度的升高而增强 ,SOD酶活性降低所造成的活性氧伤害是引起鲫幼鱼死亡的重要原因。肝组织中的 SOD酶活性和敏感性高于鳃 ,这与其执行的生理功能有关     

微生物传感器快速测定水中BOD

采用220B型BOD快速测定仪,对标准样品、地表水、生活污水、工业废水中的BOD进行测定,与五日生化培养法进行了比对分析.结果表明：该方法检出限为0.032mg/L;加标回收率在85%～117%之间;相对误差＜6%,相对标准差＜9%,有较高的精密度、准确度;测定地表水、生活污水与五日生化培养法有较好的可比性,测定工业废水存在一定的局限.同时还阐述了微生物传感器快速测定法测定BOD与五日生化培养法,并对其优缺点做了分析比较.     

Variability of the Integrated Biochemical Index in Fish Exposed to Technogenic Water of Mining and Ore-Processing Works

The hazard presented to aquatic animals by technogenic waters from mining and ore processing works, with an abnormally high potassium content and alkaline pH, was studied in experiments with fish using the integrated biochemical index (IBI) allowing an aggregate estimation of changes in the animal organism. The results showed that the IBI value directly depends on the extent of technogenic pollution, as well as on the species and age of fish.     

混凝沉淀法—微电解法—生化法处理造纸废水的试验研究

通过静态试验,研究了生化-铁碳微电解-生化、生化-铁碳微电解-混凝沉淀、混凝沉淀-铁碳微电解-生化3种工艺降解造纸废水COD的效果,考察了铁碳微电解法对造纸废水生化性能的改善。试验结果表明,经过铁碳微电解预处理后的造纸废水,其生化性能得以增强;相对混凝沉淀出水,铁碳微电解出水采用生化处理作为后续处理工艺更佳,其COD去除效果更好。     

Alkylation of metals and the activity of metal‐alkyls†

The biochemical basis for resistance to metal ion toxicity is emerging though it is complicated by the different resistance mechanisms. Several strategies for resistance to toxic metal ions have been identified:

1. The development of energy driven efflux pumps which keep toxic element levels low in the interior of the cell. Such mechanisms have been described for Cd(II) and As(V).

2. Oxidation (e.g. AsO^2‐ to AsO₄ ^3‐) or reduction (e.g. Hg²⁺ to Hg⁰) can enzymatically and intracellularly convert a more toxic form of an element to a less toxic form.

3. The biosynthesis of intracellular polymers which serve as traps for the removal of metal ions from solution such as traps have been described for cadmium, calcium, nickel and copper.

4. The binding of metal ions to cell surfaces.

5. The precipitation of insoluble metal complexes (e.g. metal sulfides and metal oxides) at cell surfaces.

6. Biomethylation and transport through cell‐membranes by diffusion controlled processes.

In this short review I shall discuss the implications of biomethylation as a detoxification mechanism for microorganisms as well as for certain higher organisms.     

Stress response to nanoplastics with different charges in Brassica napus L. during seed germination and seedling growth stages

● Higher concentrations of PS, PS-NH₂ and PS-SO₃H inhibited seed germination. ● PS, PS-NH₂ and PS-SO₃H influenced seedling growth in a dose-dependent manner. ● PS, PS-NH₂ and PS-SO₃H reduced essential nutrients uptake and plant quality. ● PS, PS-NH₂ and PS-SO₃H increased antioxidant enzyme activities and MDA content. ● Nanoplastic toxicity was related to surface charges. Nanoplastic pollution has become a significant problem in farmland systems worldwide. However, research on the effects of nanoplastics (NPs) with different charges on field crops is still limited. In our study, NPs with different charges, including unmodified polystyrene nanoplastics (PS), positively charged polystyrene nanoplastics (PS-NH₂), and negatively charged polystyrene nanoplastics (PS-SO₃H), were investigated for their impacts on seed germination and seedling growth of rape. The results showed that seed water uptake (after 12 h), seed germination, seed vigour, and relative root elongation were all significantly reduced under exposure to NPs (200 mg/L). Similarly, remarkable decreases in plant biomass (root weight, shoot weight), growth (root length, plant height), photosynthesis ability (chlorophyll a, chlorophyll b, carotenoids), essential nutrient uptake (Fe, Mn, Zn, Cu), and plant quality (soluble protein, soluble sugar, crude fibre content) of rape seedlings were also observed after exposure to NPs. Among the three kinds of NPs, PS-NH₂ showed stronger effects. Moreover, superoxide dismutase, peroxidase, and catalase activities of rape seedlings were changed, and the content of malondialdehyde was significantly increased under exposure to NPs. Furthermore, positively charged PS-NH₂ showed stronger effects on the phenotype, physiology, biochemistry, nutrient uptake, and plant quality of rape. Notably, a comprehensive toxicity evaluation revealed that PS-NH₂ had the strongest toxicity to rape. The present study provides important implications for the interaction and risk assessment of NPs and crops in soil-plant systems.     

Impact of heavy metal pollution on the hemogram and serum biochemistry of the Libyan jird, Meriones libycus

The stress profiles of the hemogram and serum biochemistry were determined in the context of heavy metal (Cd, Cu, Hg, Ni and Pb) exposure in the wild libyan jird, Meriones libycus, from one of Riyadh’s polluted areas versus a reference site. Coupling the pronounced drop in platelets (PLT) (28%) and mean platelet volume (MPV) (17%) with the insignificant responses of other red blood cell indices, suggests bone marrow suppression that is characterized by thrombocytopenia as an initial abnormality. The species-specific stress leukogram for M. libycus is expressed by leukocytosis (66%), monocytosis (40%), lymphocytosis (23%) with eosinopenia (81%) and neutropenia (42%). Hyperglycemia (50%), hyper-low-density-lipoproteinemia (38%), hypocortisolism (85%) and hypotriglyceridemia (55%) depicted serum biochemistry profile. In polluted jirds, the elevated activities of pseudocholinesterase (PChE) and serum marker enzymes (alanine aminotransferase ALT, aspartate aminotransferase AST and creatine kinase CK) strongly suggest functional damage of the liver and/or heart. A potential role of PChE in low-density lipoprotein (LDL) metabolism is implied in the joint rise of both indices and in the recognized relationship between PChE and lipid metabolites. While increased utilization in lipid metabolism and energy synthesis could rationalize the inhibition of the normal patterns of triglycerides and lactate dehydrogenase (LDH), the inhibited activities of LDH could additionally be attributed to its hormetic behavior towards low and high metal concentrations. The overall findings presented here documented the relevance of M. libycus in biomonitoring and predicting the risk imposed on human populations living in polluted areas.     

混凝-膜分离-生化(A/O)工艺处理增白剂厂生产废水

利用混凝 膜分离 生化 (A O)工艺成功地处理了增白剂厂排出的高浓度有机废水 ,并系统地阐述了各处理单元对废水的处理效果 ,分析了取得废水处理效果的原因