天敌与转Bt基因抗虫植物的协同控害作用

本文概述了转Bt基因抗虫植物对天敌的影响,特别是天敌与转Bt基因抗虫植物的协同控害作用及其对寄生昆虫抗生发展的影响研究进展。已有的研究表明转Bt基因抗虫植物对天敌并无明显不利的影响,但转Bt基因抗虫植物与天敌的协同控害作用表现出拮抗性、加和性及增效性等多种形式,这种协同作用可能还将影响到害虫对转Bt基因抗虫植物的速率。     

鸡马立克氏病抗性选育实验

马立克氏病（MD）是严重危害养鸡业发展的急性传染病。从1996年起,采用血型基因检测和后裔马立克氏病病毒（MDV）攻击选留强抗性亲本途径开展了MD抗性选育实验。结果表明：（1）亲本4上发代No.614血型基因检测阳性率逐代上升。由F0的68．8％,F1的77．3％,F2的81．8％到F3的90．5％。（2）F2－F4雏鸡10日龄MDV攻击,60日龄死亡率,亲本对No.614抗血清呈阳性反应的实验组3个世代分别是25．8％,69．2％和29．4％;亲本对No.614抗血清呈阴性反应的对照组相应是30．6％,81．0％和52．9％,实验组鞭显著低于对照组（P＜0．01或P＜0．05）。（3）实验期间F2－F4雏鸡9个内脏器官组织肿瘤病变率,实验组3个世代分别是87．6％,83．3％和58．8％;对照组相应为88．1％,84．5％和70．6％;两者比较除个别世代,个别器官实验组低于对照组（P＜0．05）外,多数没有显著差异（P＞0．05）。并对实验结果及MD抗性的遗传控制进行了讨论。     

Structure-activity relationships of novel potent MurF inhibitors

A novel class of MurF inhibitors was discovered and structure-activity relationship studies have led to several potent compounds with IC(50)=22 approximately 70 nM. Unfortunately, none of these potent MurF inhibitors exhibited significant antibacterial activity even in the presence of bacterial cell permeabilizers.     

The effect of lanthanide chloride on abscisic acid and electron-transport activity of some crops

The abscisic acid (ABA) content of the root tips of four crops grown in lanthanide chloride solution and their root lengths had been determined. At lanthanide concentrations of 5 and 10 ppm, these crops all grew well and the ABA decreased. At higher lanthanide concentrations (100–500 ppm), the ABA is increased again. At these concentrations of lanthanum chloride, the photosystems I and II (PSI and PSII) and whole electron chain transport activities were inhibited. PSII was more sensitive than PSI, and it is concluded that La³⁺ acts on the diphenylcarbazide (DPC) action place of PSII oxidizing site.     

Oxidative stress and potential free radical damage associated with photocopying. A role for ozone?

OBJECTIVE: To study the relationship between oxidative stress and potential free radical damage associated with photocopying and to explore a role for ozone emitted during the photocopying process. METHODS: 80 photocopying operators (PO) and 80 healthy volunteers (HV) were enrolled in a random control study design, in which the level of lipoperoxide (LPO, thiobarbituric acid reactive substances, TBARS) in erythrocytes and the levels of vitamin C (VC), vitamin E (VE) and beta-carotene (beta-CAR) in plasma as well as the activities of superoxide dismutase (SOD) and catalase (CAT) in erythrocytes were determined by spectrophotometric methods. RESULTS: Compared with the average values of the above biochemical parameters in the HV group, the average value of LPO (TBARS) in erythrocytes in the PO group was significantly increased (P < 0.0001), while the average values of VC, VE and beta-CAR in plasma as well as those of SOD and CAT in erythrocytes in the PO group were significantly decreased (P < 0.0001). Pearson product-moment correlation analysis showed that with the increase of the ozone level in photocopying sites and the PO duration of exposure to ozone, the level of LPO in erythrocytes in the operators was increased (P < 0.001), while the levels of VC, VE and beta-CAR in plasma as well as the activities of SOD and CAT in erythrocytes in the operators were decreased (P < 0.01-0.0001). CONCLUSION: The findings in this study suggest that ozone causes oxidative damage in copier operatives.     

Purification,characterization and crystallization of a group of earthworm fibrinolytic enzymes from Eisenia fetida

Seven fibrinolytic enzymes were purified from the earthworm Eisenia fetida. The molecular weights of the enzymes were 24663, 29516, 29690, 24201, 24170, 23028 and 29595, and the respective isoelectric points were 3.46, 3.5, 3.5, 3.68, 3.62, 3.94 and 3.46. All the proteases showed different fibrinolytic activity on fibrin plates. Studies on substrate specificity and inhibition indicated that they belonged to different types of serine proteases. N-Terminal sequencing indicated their high homology to those from the earthworm Lumbricus rubellus. All the enzymes have been crystallized.     

Dentiphilometra monopteri n. gen., n. sp. (Nematoda: Philometridae) from the abdominal cavity of the ricefield eel Monopterus albus in China

A new genus and species of philometrid nematode Dentiphilometra monopteri n. gen., n. sp., are described on the basis of the specimens found in the abdominal cavity of the ricefield eel (swamp-eel) Monopterus albus (Zouiev) from Liangzi Lake (the Yangtze River drainage system), Hubei Province, in central China. Dentiphilometra, assigned to the Philometrinae, differs from other genera of this subfamily mainly in the presence of a sclerotized oral ring armed on its inner surface by numerous small peribuccal teeth in the gravid female. The new species is characterized by minute cephalic papillae, a greatly developed anterior esophageal bulb separated from the cylindrical part of the esophagus, anterior extention of the esophageal gland anterior to the nerve ring, and by large caudal projections in females and equal spicules 0.051-0.096 mm long in males. This is the second philometrid species recorded from fishes of the Synbranchiformes.     

Impaired glucose homeostasis in insulin-like growth factor-binding protein-3-transgenic mice

Glucose homeostasis was examined in male transgenic (Tg) mice that overexpressed the human insulin-like growth factor (IGF)-binding protein (IGFBP)-3 cDNA, driven by either the cytomegalovirus (CMV) or the phosphoglycerate kinase (PGK) promoter. The Tg mice of both lineages demonstrated increased serum levels of human (h) IGFBP-3 and total IGF-I compared with wild-type (Wt) mice. Fasting blood glucose levels were significantly elevated in 8-wk-old CMV-binding protein (CMVBP)-3- and PGK binding protein (PGKBP)-3-Tg mice compared with Wt mice: 6.35 +/- 0.22 and 5.22 +/- 0.39 vs. 3.99 +/- 0.26 mmol/l, respectively. Plasma insulin was significantly elevated only in CMVBP-3-Tg mice. The responses to a glucose challenge were significantly increased in both Tg strains: area under the glucose curve = 1,824 +/- 65 and 1,910 +/- 115 vs. 1,590 +/- 67 mmol. l(-1). min for CMVBP-3, PGKBP-3, and Wt mice, respectively. The hypoglycemic effects of insulin and IGF-I were significantly attenuated in Tg mice compared with Wt mice. There were no differences in adipose tissue resistin, retinoid X receptor-alpha, or peroxisome proliferator-activated receptor-gamma mRNA levels between Tg and Wt mice. Uptake of 2-deoxyglucose was reduced in muscle and adipose tissue from Tg mice compared with Wt mice. These data demonstrate that overexpression of hIGFBP-3 results in fasting hyperglycemia, impaired glucose tolerance, and insulin resistance.