Effects of optimum doses of nitrogen,phosphorus, potassium and calcium on silkworm,Bombyx mori L., growth and yield

Silkworm rearing has been an income source for small-holding farmers in Pakistan. Over the years efforts have been made to improve silkworm quality and quantity and thus develop better prospects for increasing yield and income. Mulberry leaves Morus alba L. in a series of experiments have been supplemented with various nutrients in different doses and combinations. Relative success has been achieved in this context. In our present experiments on silkworm Bombyx mori L., we fed the larvae on mulberry leaves supplemented with different doses of N (0.2%), P (0.1%), K (0.3%) and Ca (0.1%) at 26 ± 3°C with 65 ± 5% relative humidity. The results showed better outputs in terms of food consumption (72.55 g/10 larvae), coefficient of utilization (76.45%), body weight (70.07 g/10 larvae) and body length (8.56 cm/larvae) than where simple mulberry leaves were offered. Our net gains with these production parameters have been in terms of heavier cocoons with and without pupa (2.25 and 0.69 g/cocoon), respectively.     

抗肿瘤肽QX3-1融合蛋白在大肠埃希菌中表达条件的优化

优化抗肿瘤肽QX3-1融合蛋白在大肠埃希菌中的表达条件,提高表达量。从培养基、诱导温度、诱导剂浓度和诱导时间4个单因素实验入手,优化QX3-1融合蛋白的表达条件,通过聚丙烯酰胺凝胶电泳(SDSPAGE)和Band Scan凝胶分析软件分析QX3-1融合蛋白的表达量。p ED-QX 3-1/BL21重组菌在LB、大豆肉汤、TB和酪蛋白胨(自制) 4种培养基中,于酪蛋白胨培养基中的表达量最高;在20、25和37℃三种诱导温度下,于37℃环境中表达量最高;在1、5、10、15和20 mmol/L乳糖浓度的诱导下,于10 mmol/L乳糖诱导最佳;在30 h的诱导时间内,于第24小时,融合蛋白的表达量最高。从培养基、诱导温度、诱导剂浓度和诱导时间4个变量中筛选出适合QX3-1融合蛋白表达的最佳组合,使融合蛋白的表达量达到了31. 2%,相比未优化前提高了近一倍。     

裂叶沙参和泡沙参种群有性生殖和无性繁殖的比较

通过对裂叶沙参(Adenophora lobophylla Hong)和泡沙参(A.potaninii Korsh.)种群有性生殖和无性繁殖特性的对比,揭示濒危植物裂叶沙参的种群内部致濒机制。结果表明:裂叶沙参种群幼苗抢占草本层上层空间能力弱于泡沙参种群;裂叶沙参种群是以相对长的生殖期和高产籽量来适应环境;裂叶沙参种群开花结实量虽高于泡沙参种群,但其中成熟种子少,种子质量差,致使其种群由种子到一年生幼苗的转化率极低,并且幼苗生活力弱,是导致其种群濒危的重要内部原因。裂叶沙参种群除有性生殖外还兼有较弱的无性繁殖,是对其有性生殖的一个重要补充。     

Lethal and repellent effects of transfluthrin and metofluthrin used in portable blowers for personal protection against Ochlerotatus togoi and Aedes albopictus (Diptera: Culicidae)

The lethal efficacy of three vaporizing insecticides – 0.6% transfluthrin and 0.6% metofluthrin in portable battery‐powered blowers and 2.5% bioallethrin in electric mats – was assessed in unventilated and ventilated screened room conditions against Ochlerotatus togoi (Theobald) females. The mosquitoes were highly susceptible to transfluthrin and metofluthrin. Mean mortality rates of mosquitoes exposed to transfluthrin and metofluthrin in portable blowers ranged from 95 to 100% at a distance of 10 cm from mosquito cages in both room conditions; this was a >2.4‐fold greater mortality rate than for mosquitoes exposed to bioallethrin in electric mats under the same conditions (mean 40%). The three insecticides showed a decrease in mortality rate at a distance of 70 cm: rates were <5.0, 32.5, 85.0 and 90.0% for 10, 30, 60, and 120 min after exposure, respectively, for the same exposure periods in a closed room. In semi‐field repellent tests with human volunteers, 0.6% concentrations of transfluthrin and metofluthrin provided mean biting protection of 76.1 and 59.9% on legs, 68.5 and 52.1% on arms, 63.4 and 63.1% on the chest, and 87.1 and 52.9% on the face, respectively. In field tests, 0.6% transfluthrin effectively repelled Armigeres subalbatus and Aedes albopictus, with mean biting protection of 85.4 and 89.3% on exposed legs and arms, respectively, of the human volunteers. Metofluthrin at 0.6% also effectively repelled Ar. subalbatus, with mean biting protection levels of 71.8 and 73.5% on the legs and arms, respectively. There was no significant difference of repellent activity between the two vaporizing insecticides in the field.     

General biology of Ostrinia palustralis memnialis (Walker), a potential biological control agent of Rumex spp. in Korea

Ostrinia palustralis memnialis is an oligophagous insect that feeds on the species of the genus Rumex. Continuous rearing of O. palustralis memnialis was carried out from 2004 to 2005, and its general biology was studied. The preliminary host specificity test showed a promising result for O. palustralis memnialis as a potential biological control agent for Rumex spp.