Study of the amino acid sequence of latroinsectotoxin from black widow spider venom]

The N-terminal amino acid sequence of alpha-latroinsectotoxin from the venom of Latrodectus mactans tredecimguttatus was determined. Then the toxin was digested by trypsin and total or partial amino acid sequences of twenty-six tryptic peptides were established. This resulted in the structural information needed for the construction of probes followed by the cloning of the alpha-latroinsectotoxin structural gene.     

Effects of Low Root Temperature on Ion Uptake and Ion Translocation in Wheat

Roots of wheat seedlings (Triticum aestivum L. cv. Weibulls Starke) were cooled (+1°C) for 24 h while the shoots were kept at 25°C. The treatment induced an increased water deficit in the leaves. Fresh weight, dry weight, and the uptake and distribution of potassium and calcium were measured before and after cooling. Growth, measured both as fresh weight and dry weight increase, was reduced during the cold treatment. Afterwards (at 20°C), growth recovered to nearly pre-stress rates. Analysis of the potassium fluxes in and out of the roots by ⁸⁶Rb techniques showed that influx, and to a lesser extent efflux, were inhibited at low temperature. The result was a net potassium uptake rate of one-third that of unstressed plants. After the cooling period the potassium influx increased to the rate of control plants. The potassium efflux increased to one and one-half times the rate of unstressed wheat so that net uptake was negative. The increase in potassium efflux was explained by a higher permeability of the root cell membranes after cooling. The net uptake of calcium was reduced to one-third by root cooling. Contrary to potassium uptake, calcium uptake increased under post-stress conditions, partly due to a low efflux rate. During root cooling there was a redistribution of dry matter from the leaves down towards the lower part of the shoot. Afterwards the original distribution of dry matter was reestablished. The net flow of potassium and calcium followed a similar pattern as dry matter, suggesting a growth-regulated flow.     

The Deuterator: software for the determination of backbone amide deuterium levels from H/D exchange MS data

Background  

The combination of mass spectrometry and solution phase amide hydrogen/deuterium exchange (H/D exchange) experiments is an effective method for characterizing protein dynamics, and protein-protein or protein-ligand interactions. Despite methodological advancements and improvements in instrumentation and automation, data analysis and display remains a tedious process. The factors that contribute to this bottleneck are the large number of data points produced in a typical experiment, each requiring manual curation and validation, and then calculation of the level of backbone amide exchange. Tools have become available that address some of these issues, but lack sufficient integration, functionality, and accessibility required to address the needs of the H/D exchange community. To date there is no software for the analysis of H/D exchange data that comprehensively addresses these issues.     

Prevalence of risk factors for cardiovascular disease in Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992

BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.     

大鼠肠内容物细菌基因组DNA提取方法的比较

目的比较两种肠内容物前处理和两种提取方法对清洁级SD大鼠肠内容物细菌基因组DNA提取效率。方法分别选用PBS多次离心漂洗、液氮破细胞两种前处理方法和酚/氯仿抽提、试剂盒过柱法两种提取方法进行组合分析,对4份肠内容物和16份含金黄色葡萄球菌肠内容物进行随机提取。结果大鼠肠内容物细菌基因组DNA含量和纯度测定结果显示,与PBS反复离心相比,液氮研磨前处理能显著提高大鼠肠内容物基因组DNA。荧光定量PCR表明,液氮研磨前处理较PBS反复离心能更好地收集细菌基因组DNA,其Ct值最低。结论研究结果表明,采用液氮研磨试剂盒法在大鼠肠内容物DNA提取中是较为优良的方法,该方法为建立实验动物中微生物的定量PCR检测方法打下了基础。     

秦渭玫瑰精油研究

采用ISO9842和GB11538-89对在陕西渭南栽培的大马士革玫瑰“卡赞勒克”精油(工业化蒸馏法提取产品)进行了分析,结果表明,精油产品各项指标均符合ISO 9842和保加利亚БДС653标准要求。证明引种国际香型(纯甜型)玫瑰品种在陕西渭南栽培是成功的,所用精油提取工艺是合理的。     

Functional features of the nucleolar organizer in developing oocytes of juvenile birds

The genes of rRNA in the nucleolar organizer region (NOR) are inactivated in the oocytes of adult birds despite the functioning of lampbrush chromosomes. The nucleolus is not formed during all stages of the oocyte development. On the other hand, two morphological forms of oocytes differing by the presence of nucleolus in the germinal vesicle are described in the ovaries of juvenile birds. The activation and function of the ribosomal genes in avian oogenesis is still vague. In this work, the NOR activation in chicken (Gallus gallus domesticus) oocytes is confirmed with the help of fluorescence immunohistochemistry (antibodies against nucleophosmin, fibrillarin, and UBF1) and in situ nucleic acid hybridization (FISH with the probe to ITS1 in pre-rRNA). It is demonstrated that the nucleolus in the oocytes at the lampbrush stage in the chicken ovaries is fragmented after complete inactivation of the ribosome genes: the nucleolar fragments contain fibrillarin but do not contain pre-rRNA molecule. The utility of the ovary 3D reconstruction using serial histological sections for quantification of sex cell population heterogeneity in the ovaries of juvenile birds is demonstrated. The obtained results improve the current insight into the functional NOR state in the oocytes of juvenile female birds and contribute to the concept of diversity in the scenarios of gametogenesis.     

草地贪夜蛾对不同品种玉米的适应性比较研究

为了解不同玉米品种对草地贪夜蛾生长发育的影响,本文通过比较草地贪夜蛾Spodoptera frugiperda取食2种糯质型玉米(明玉1203和苏玉糯5号)与3种普通玉米(苏玉29、苏玉30和郑单958)后的发育历期、死亡率、蛹重、成虫畸形率、繁殖力与幼虫取食选择率等生物学参数,分析了草地贪夜蛾对不同品种玉米的适应性差...