A Functional Approach to the Assessment of the Nutritional Value of Particulate Organic Matter

Organic matter lability can be determined with different approaches, based on the quantitative and qualitative estimate of its nutritional value. the C/N ratio and the particulate organic matter (as the sum of protein, carbohydrate and lipid bulks) vs total suspended matter (POM/TSM) deal with a quantitative assessment of the organic matter bulk, while other indices such as proteins/carbohydrates ratio (PRT/CHO) may give also qualitative information. Gordon (1970) proposed a functional approach, based on organic carbon decrease after enzymatic digestion. Coupling Gordon's approach with the evaluation of the main biochemical components (proteins, carbohydrates and lipids) contained in the particulate organic matter, a simple method to assess lability and nutritional value of organic substrates is proposed.

Water samples were collected at the surface and close to the bottom in a shallow coastal station (10 m depth) in the Marconi Gulf (Ligurian Sea, NW Mediterranean). the difference between “total labile” and “hydrolyzed labile” organic matter (respectively before and after enzymatic digestion) suggests a relevant presence of resuspended refractory materials vs about 60% of labile hydrolyzed organic matter, thus confirming the importance of a more qualitative approach to organic matter studies.     

Larvae of Sand Smelts (Atherina hepsetus L.) as a Bioindicator of Pollution in the Black Sea Coastal Waters

The activity of antioxidant enzymes and electrophoretic protein spectra were studied in sand smelt larvae inhabiting from five Sevastopol bays with different degrees of anthropogenic impact. The activity of antioxidant enzymes and the heterogeneity of electrophoretic protein spectra proved to increase in the larvae from the most polluted waters. The possibility of using these parameters as biological markers for assessing the influence of pollution on the early stages of fish ontogeny and the marine environment are discussed.     

MOBILE汽车源排放因子计算模式研究

在盆栽条件下，研究了土壤中Ｐｂ、Ｈｇ及其相互作用对烟草叶片活性氧代谢的影响．实验结果表明：随着Ｐｂ、Ｃｄ处理浓度的增加，ＰＯＤ活性逐渐增加，ＳＯＤ开始上升后转而下降，ＣＡＴ活性逐渐下降．它既诱导了活性氧的生成，又影响活性氧清除系统对活性氧的清除能力，结果造成活性氧的产生和清除之间的不平衡，致使相关的生理生化过程紊乱，加速了叶片衰老的进程．Ｐｂ、Ｈｇ对烟草叶片抗氧化酶代谢的影响，两者之间存在着一定的协合作用．     

Normal ranges of the activities of ten different enzymes in 100 independent preparations of chorionic villi. Comparison of specimens from induced abortions,biopsies, and cultured cells

In order to obtain a large set of normal control values, the activities of three cytosolic enzymes of purine metabolism and seven lysosomal enzymes were determined in homogenates of chorionic villi derived from induced abortions of normal pregnancies (7th–12th week) in about 100 individual cases. Possible reasons for the rather wide ranges of normal distributions of enzyme activities are discussed. The values are compared: (1) with available data in the literature; (2) with activities determined in decidual homogenates prepared from the same samples; (3) with activities of cells of cultures established and grown from villi in the same samples; and (4) with enzyme activities measured in chorionic biopsies using the same methods. Implications for the prenatal diagnosis of the associated metabolic diseases are considered.     

Prenatal diagnosis of carbamoyl-phosphate synthetase deficiency by fetal liver biopsy

In a pregnancy at risk for carbamoyl-phosphate synthetase (CPS) deficiency, prenatal diagnosis was attempted by fetal liver biopsy, performed at 18 weeks of gestation. CPS activity was absent and the diagnosis was confirmed after termination of the pregnancy. The technique employed for fetal liver biopsy is described together with an evaluation of its possible role in prenatal diagnosis.     

Microvillar enzyme assays in amniotic fluid and fetal tissues at different stages of development

A systematic study of microvillar enzyme activities in the amniotic fluid in correlation with their values in different fetal tissues during development has been undertaken. Microvillar enzymes appeared in the amniotic fluid at the time of disappearance of the anal membrane, 12–13 weeks, and declined from the 18th week until the 24th week. The study of fetal tissues and fluids has shown that gamma-glutamyltranspeptidase is mainly of liver origin. The significant decrease of the activities of these amniotic fluid enzymes has been the basis of prenatal diagnosis of cystic fibrosis. These assays may be useful for the diagnosis of certain digestive tract abnormalities at later stages of pregnancy.     

Discriminant analysis for assessing the value of amniotic fluid microvillar enzymes in the prenatal diagnosis of cystic fibrosis

We have analysed the sensitivity, specificity, and reliability of biochemical diagnosis based on microvillar membrane enzyme assay and using discriminant analysis in amniotic fluid samples obtained from 54 pregnancies at high risk for cystic fibrosis and 125 normal pregnancies. Our results show that amniotic fluid trehalase, alkaline phosphatase, alkaline phosphatase isoenzymes and gamma-glutamyltransferase enzyme activities measured during 16–20 gestational weeks, in spite of their non-specificity for cystic fibrosis, have a very good predictive value for fetal cystic fibrosis or exclude the possibility of the disease. Overall enzyme activity analysis provided over 90 per cent reliability of the method.     

复合垂直流构建湿地基质微生物类群及酶活性的空间分布

对构建湿地基质微生物类群数目及酶活性的空间分布特点进行了研究，为进一步深入研究构建湿地净化污水的机制提供了可能，研究表明：（1）不同月份构建湿地基质的微生物类群目是不相同的。（2）基层不同层次之间其微生物类群数目不相同，上层数目较中下层多，最多几乎达三个数量级，（3）下行流池中的微生物类群数目较上行流池多。（4）下行流池中的脲酶活性较上行流池高，且上层高于中下层。（5）上行流池中的磷酸酶活性较下行流池为高。     

季节性冻融对扎龙湿地土壤微生物群落结构和胞外酶活性的影响

选取扎龙湿地芦苇沼泽为研究对象,采用磷脂脂肪酸法和微孔板法研究了季节性冻融期土壤微生物群落结构和胞外酶活性的动态变化规律.结果表明,微生物总磷脂脂肪酸（PLFA）含量和细菌PLFA含量均呈先降低后升高趋势,而真菌PLFA含量呈先升高后降低趋势.冻融初期至融冻初期,β-葡萄糖苷酶显著降低了71.84%,β-N-乙酰氨基葡萄糖苷酶表现为先升高后降低趋势,酸性磷酸酶在融冻初期最高、冻融初期最低,过氧化物酶和多酚氧化酶峰值均出现在融冻后期.主成分分析表明,季节性冻融显著改变了土壤微生物群落结构.冗余分析发现,土壤含水率与总PLFA、细菌、革兰氏阳性菌、革兰氏阴性菌、放线菌、过氧化物酶和多酚氧化酶呈显著正相关（p<0.05）;土壤全磷、速效磷、速效氮与真菌和β-N-乙酰氨基葡萄糖苷酶呈显著正相关;β-葡萄糖苷酶主要受土壤碳氮比和有机质影响,而土壤微生物与胞外酶活性在不同冻融时期具有显著相关性（p<0.05）.因此,探究全球变化背景下土壤微生物和胞外酶对季节性冻融过程的响应机制,可为深入解析扎龙湿地土壤质量演变特征及湿地生态系统功能的恢复与保护提供科学依据.     

城市污泥与园林废弃物混合堆肥施用对林地土壤微生物量碳、氮及酶活性的影响

研究城市污泥和园林废弃物混合堆肥施用对土壤微生物量碳(SMBC)、微生物量氮(SMBN)及酶活性的影响,可为林地施用混合堆肥产品的安全及功效性评价提供科学依据.本研究采用大田试验,选取紫穗槐为研究对象,将污泥和园林废弃物以3种比例(GF(纯园林废弃物)、SGA(V(污泥)∶V(园林废弃物)=1∶3)、SGB(V(污泥)∶V(园林废弃物)=1∶1))进行混合堆肥,每种堆肥产品分别按0、5、10、50 kg·株-1(分别记作CK、T5、T10、T50)均匀施入样地.施肥1年后,于田间采样测定土壤生物活性指标及理化性质,采用主成分分析及单、双因素方差分析法研究混合堆肥产品施用后对土壤酶活性及微生物量碳、氮含量的影响.结果表明:施入GF、SGA和SGB时,SMBC和SMBN均在施用量50 kg·株-1时达到最大.随着施用量的增加,土壤酶指数(SEI)总体上呈现逐步递增的趋势,施入GF、SGA、SGB时,各个施肥梯度处理的土壤酶指数较CK分别增加93.33%~186.67%、14.58%~54.17%、119.05%~204.76%.通过主成分分析,依据各处理综合得分情况,不同堆肥产品总体上表现为:SGBGFSGA.施入GF、SGA和SGB,不同处理综合得分均为T50T10T5CK.说明施用堆肥产品能够提高土壤微生物量,增加土壤酶活性,改善土壤的生物环境.