运行负荷对酶制剂废水厌氧颗粒污泥形成的影响

通过逐步提高污泥负荷和一步提高污泥负荷2种方法,研究了UASB反应器中运行负荷对酶制剂废水厌氧颗粒污泥形成的影响．结果表明,逐步提高污泥负荷,有利于颗粒污泥的形成．对酶制剂废水厌氧处理而言,在一定程度上,脱氢酶活性的变化可以反映出处理体系中微生物活性的变化,辅酶F420含量变化可定性地判断污泥的产甲烷活性．同时,还从运行良好的反应器中分离到1株优势产甲烷细菌M3菌,依据其形态和生理生化特征,将该菌鉴定为甲烷球形菌属(Methanosphaera sp．)．     

生物可降解螯合剂[S,S]-乙二胺二琥珀酸和乳酸乙酯提取土壤中重金属的研究

研究了生物可降解的有机螯合剂[S,S]-乙二胺二琥珀酸([S,S]-EDDS,简写为EDDS)和乳酸乙酯(EL)对重金属污染土壤中重金属的提取效率,并用X射线衍射(XRD)和红外光谱(FT-IR)分析了螯合剂提取对土壤理化性质的影响.结果表明:EDDS对土壤中的Cd、Cu、Pb和Zn有较高的提取率,效果比EL好;EDDS和EL混合提取的重金属提取率增加,但相比单独使用EDDS没有超过10%.FT-IR分析表明,提取前后FT-IR谱图中特征吸收频率没有显著改变,但强度有所改变.XRD分析表明,提取前后土壤晶格结构发生明显的变化,螯合剂提取改变了土壤微观结构.     

HPLC determination of chlorate metabolism in bovine ruminal fluid

Salmonella and Escherichia coli are two bacteria that are important causes of human and animal disease worldwide. Chlorate is converted in the cell to chlorite, which is lethal to these bacteria. An HPLC procedure was developed for the rapid analysis of chlorate (ClO₃ ^?), nitrate (NO₃ ^?), and nitrite (NO₂ ^?) ions in bovine ruminal fluid samples. Standard curves for chlorite, nitrite, nitrate, and chlorate were well defined linear curves with R² values of 0.99846, 0.99106, 0.99854, and 0.99138, respectively. Concentrations of chlorite could not be accurately determined in bovine ruminal fluid because chlorite reacts with or binds a component(s) or is reduced to chloride in bovine ruminal fluid resulting in low chlorite measurements. A standard curve ranging from 25 to 150 ppm ClO₃ ^? ion was used to measure chlorate fortified into ruminal fluid. The concentration of chlorate was more rapidly lowered (P < 0.01) under anaerobic compared to aerobic incubation conditions. Chlorate alone or chlorate supplemented with the reductants sodium lactate or glycerol were bactericidal in anaerobic incubations. In anaerobic culture, the addition of sodium formate to chlorate-fortified ruminal fluid appeared to decrease chlorate concentrations; however, formate also appeared to moderate the bactericidal effect of chlorate against E. coli. Addition of the reductants, glycerol or lactate, to chlorate-fortified ruminal fluid did not increase the killing of E. coli at 24 h, but may be useful when the reducing equivalents are limiting as in waste holding reservoirs or composting systems required for intense animal production.     

Metabolic effects of diazinon on the European eel

Abstract

Eels were exposed to a sublethal diazinon concentration of 0.042 mg/L for exposure times of 6, 24, 48, 72 and 96 hours. Biochemical analyses of blood composition, such as plasma glucose, total plasma cholesterol and triglycerides, plasma lactate, plasma urea and uric acid, showed significant differences between treated and control animals. Plasma glucose and lactate increased after 6 hours exposure to the insecticide. Plasma cholesterol and triglycerides content decreased during 96 hours treatment. Urea levels increased at 72 hours while uric acid content decreased significantly at 24, 72 and 96 hours exposure to the pesticide.

The observed effects of diazinon on eel metabolism suggested that the treated fish was faced with a serious metabolic crisis, and the fish looked for alternative methods of metabolism to overcome the toxic stress.     

C/N比对嗜酸细菌X-29产氢能力及其酶活性的影响

C/N比影响细菌的物质和能量代谢,为了提高产氢细菌的产氢效能,通过间歇产氢实验和酶活性分析方法,分析了在不同C/N比下嗜酸产氢细菌X-29的产氢能力以及氢化酶和乙醇脱氢酶的活性表达情况.研究结果表明,C/N比对产氢细菌的代谢及其相关酶的表达有显著的影响.虽然在不同C/N比下单位生物量的液相末端发酵产物差异不大,但是产氢能力存在显著的差异,当C/N比为14时产氢细菌X-29具有最大累积产氢量2 210.9mL/g.在不同C/N比下氢化酶的表达活性不同,氢化酶活性随着发酵的进行达到高峰后迅速降低,氢化酶的表达周期较短.乙醇脱氢酶活性随着代谢进程逐渐升高后而趋于平稳,不同C/N比时表达活性差异较小,表达周期较长.在C/N比为14时,氢化酶和乙醇脱氢酶的活性最高,分别为2.8μmol·(min·mg)^-1和33.2μmol·(min·mg)^-1.     

Monitoring impact of mefenacet treatment on soil microbial communities by PCR-DGGE fingerprinting and conventional testing procedures

The effect of acetanilide herbicide mefenacet on soil microbial communities was studied using paddy soil samples with different short-term treatments. The culturable bacteria （plate counts）, dehydrogenase activity and changes in community structure （denaturing gradient gel electrophoresis （DGGE） analysis） were used for biological community assessments. Mefenacet was a significant stimulus to cultural aerobic bacteria and dehydrogenase activity while Sphingobacterium multivorum Y1, a bacterium efficiently degrading the mefenacet, only induced the increasing colony-forming unit （CFU） of bacteria but little effect on dehydrogenase activity during the whole experiment. The degree of similarity between the 16S rDNA profiles of the communities was quantified by numerically analyzing the DGGE band patterns. Similarity dendrograms showed that the microbial community structures of the mefenacet-treated and non-treated soils were not significantly different. But supplement of S. multivorum Y1 could increase the diversity of the microbial community in the mefenacet-polluted paddy soil. This work is a new attempt to apply the S. multivorum Y1 for remediation of the mefenacet-polluted environments.     

废水中GaAs、Ga~(3+)、Ge~(4+)对活性污泥脱氢酶的影响及其抑制动力学

以活性污泥脱氢酶的活性作为毒性指标,研究了半导体材料GaAs、Ga~(3+)、Ge~(4+)对活性污泥活性的抑制影响,并用Hg~(2+)作为参比材料;同时对抑制动力学也作了初步研究。实验表明,GaAs、Ga~(3+)、Ge~(4+)及Hg~(2+)的10％抑制浓度分别为45.00,371.63,0.13ppm/gMLSS,GaAs、Ga~(3+)、Ge~(4+)和Hg~(2+)在浓度分别为180,700,250和1.25ppm/g MLSS时的抑制常数分别为1.30×10~(-3),7.05×10~(-3),6.12×10~(-3)和5.49×10~(-3)mmol,且其抑制类型均属可逆非竞争性抑制。     

Prenatal diagnosis of pyruvate dehydrogenase E1α subunit deficiency

Pyruvate dehydrogenase (PDH) E1α subunit deficiency is an X-linked inborn error of metabolism affecting males and females with equal frequency. The diagnosis is usually based on determination of enzyme activity, although this may present difficulties in some females because of X-inactivation patterns favouring expression of the normal X chromosome. This is a particular problem for prenatal diagnosis using chorionic villus cells where normal enzyme assay results do not necessarily exclude the diagnosis and confirmatory X-inactivation analysis may be complicated by variable methylation of active and inactive X chromosomes. We describe prenatal diagnosis in two pregnancies in a family following diagnosis of a PDH E1α deficient male. The first prenatal diagnosis was performed by enzyme assay, but by the time of the subsequent pregnancy, the underlying mutation in the affected male had been identified and direct gene analysis was possible. This study highlights the limitations of diagnosis of PDH E1α deficiency based on measurement of the gene product and illustrates the need for mutation analysis in affected individuals.     

Prenatal diagnosis of medium-chain acyl-coenzyme A dehydrogenase deficiency

A fatal case of medium-chain acyl-coenzyme A dehydrogenase deficiency is described in a patient who presented with hypoglycaemia and a gross non-ketotic dicarboxylic aciduria. Cultured skin fibroblasts released ¹⁴CO₂ from [1–¹⁴C] octanoic acid at half the normal rate. Prenatal diagnosis was undertaken in a subsequent pregnancy in which cultured amniotic fluid cells revealed a marked reduction in octanoate oxidation indicative of an affected fetus. The pregnancy was terminated and the diagnosis was confirmed by enzyme analysis of skin fibroblasts taken from the fetus. The high residual octanoate oxidation by affected fibroblasts together with the absence of any characteristic abnormality of amniotic fluid organic acids are a potential limitation to the reliability of this type of prenatal diagnosis.     

蚯蚓处理对污泥中微生物碳量及脱氢酶活性的影响

将含水率80.6%的脱水污泥制成5 mm的污泥颗粒,以添加蚯蚓(赤子爱胜蚓)为处理组,无蚯蚓为对照组,测定不同时期污泥的理化性质、微生物碳量(MBC)和脱氢酶活性(DHA)的变化,重点研究了蚯蚓对污泥降解过程中MBC和DHA变化的影响.结果表明,相比对照组,蚯蚓处理组p H变化幅度较小;实验结束时,蚯蚓处理组的电导率(EC)和溶解性有机碳(DOC)显著高于对照组,而有机质(OM)显著低于对照组.实验前30 d,蚯蚓处理组MBC显著高于对照组,40 d至实验结束,蚯蚓处理组MBC显著低于对照组.DHA的结果表明,蚯蚓处理组和对照组在前30 d并没有显著性差异,40 d后蚯蚓处理组的DHA显著低于对照组,DHA稳定在2.98~6.40 mg·g-1·h-1(以TPF计).相关分析表明,DHA、MBC和OM之间显著正相关.研究表明,接种蚯蚓在实验前期显著提升了系统的微生物量,加快污泥有机质的降解,从而导致后期产物的微生物量及其活性较低,最终产物更稳定.