羊踯躅提取物对日本血吸虫虫卵肉芽肿影响

对感染15条日本血吸虫尾蚴的雌性小鼠分别于感染后45 d起灌胃羊踯躅提取物及吡喹酮,结果小鼠肝内虫卵肉芽肿平均直径和肉芽肿内嗜酸性粒细胞明显减少。试验结果表明,羊踯躅提取物与吡喹酮对血吸虫虫卵肉芽肿的发展具有明显抑制作用。     

免疫胶体金技术诊断日本血吸虫病的研究进展

血吸虫病是一种分布广泛、危害严重的人畜共患寄生虫病。近年来,日本血吸虫病在我国部分地区死灰复燃,造成具大的经济损失。国内外对该病的检测技术研究较多,目前,诊断日本血吸虫病的经典方法仍是病原学诊断。文章对胶体金标记技术的基本原理、免疫胶体金的制备方法及其在免疫诊断中的常见标记对象做了简要介绍,并对免疫胶体金技术诊断日本血吸虫病的研究状况进行了综述。     

Application of Bradyrhizobium japonicum and Phosphorus Fertilization Improved Growth,Yield and Nodulation of Soybean in the Sub-humid Hilly Region of Azad Jammu and Kashmir,Pakistan

Two separate experiments (pot and field) were conducted to examine the response of soybean to Bradyrhizobium japonicum and phosphorus (P) fertilization. Different treatments were i) Rhizobium strains (0, S377, S379, and the mixture of S377 + S379 i.e. S₀, S₁, S₂, S₃); ii) phosphorus (field only, 0, 50, 100 kg ha-¹i.e. T₀, T₁, T₂) and iii) two soils (pot only) i.e. autoclaved (A₁) and non-autoclaved (A₀). A soybean cultivar NARC-1 was tested for estimating growth traits, nodule number and mass, root development and yield traits. In the pot experiment, total number of nodules both in the A₀ and A₁ were negligible but increased significantly following the application of Bradyrhizobium japonicum. In the field experiment, number of nodules increased from 6 in the control treatment without strains to a maximum of 86 in S₃T₁. Shoot dry weight increased significantly from 11.8 g plant-¹ in the control soil to 15.6 g plant-¹ in S₃T₁. Root length was increased but root mass was unaffected. Soybean seed yields ranged between 615 and 1003 kg ha-¹ against 543 kg ha-¹ in the control soil indicating a maximum of 85% increase over control. Shoot dry weight and seed yield had significant correlation with nodulation (R² = 0.91). The results of experiments revealed significant positive effects of rhizobium inoculation and P fertilization on growth, nodulation and yield of soybean and, generally, mixture of strains (S₃) was more effective than the strains S₁ and S₂. Results also indicated that high application of P (100 kg P₂O₅ ha-¹) reduced the efficiency of inoculants for nodule mass and seed yield.     

唐家河自然保护区连香树种群结构与数量动态

以种群静态生命表及生存分析理论为基础,以林木径级结构代表年龄结构,利用生存函数分析等方法,对唐家河自然保护区连香树种群的结构及数量动态特征进行了研究。结果表明:(1)研究区域内连香树种群结构基本呈金字塔型,其种群内幼苗较少,中老龄个体较多;(2)种群死亡率和消失率曲线变化趋势基本一致,在第Ⅱ龄级出现峰值,即幼苗死亡率较高;种群存活曲线趋于Deevey-Ⅱ型;(3) 4个生存函数曲线表明,连香树种群具有前期锐减、中后期相对稳定和末期逐渐衰退的特点,目前种群已处于衰退的早期。     

四川白河自然保护区连香树的空间分布与种群特征

以四川白河自然保护区连香树为研究对象,采用访问法、样线法和样方法相结合,调查连香树的空间分布位点、种群特征和干扰因素。调查结果表明:保护区有连香树365株,适宜面积约1 995.46 hm2;海拔1 900～2 200 m区域的连香树株数占总株数的89.53%,尤其是海拔2 000～2 100 m分布最为密集(占43.01%);径级分布为纺锤形,自然更新差,种群呈不稳定状态,胸径在12～32 cm之间的有238株(占65.20%)。连香树主要分布区与传统耕作区和放牧区的重叠性高,林地转化成耕地及放牧践踏是连香树种群数量和栖息地下降的主要原因;减少人为干扰、就地保护与监测、建立天然母树园、种子繁殖和扦插是保护连香树种群的有效措施。     

日本血吸虫中国大陆株22.6kD膜相关蛋白基因的克隆与表达

以日本血吸虫 mRNA 为模板,用 RT-PCR 法快速克隆到一大小约600bp 的 DNA 片段,DNA 序列分析证实,所扩增到的 DNA 片段中含有日本血吸虫22.6kD 膜相关蛋白(Sj-22.6(Ch))基因,将该基因重组到表达型质粒 pGEX-4T 中,表达的 GST 融合蛋白分子量约48kD,用谷胱甘肽琼脂塘凝胶亲和层析柱纯化的重组蛋白不仅纯度好,而且得率高,纯化产量可达40mg·L~(-1)培养物,免疫试验结果表明该重组蛋白具有良好的抗原性,为其在血吸虫病抗感染中的免疫作用研究创造了条件.     

Time-course of dinitrogen fixation of promiscuous soybean cultivars measured by the isotope dilution method

 Soybean cultivars capable of nodulating with indigenous Bradyrhizobium spp. have been developed by the International Institute of Tropical Agriculture (IITA) and national programs in Africa in order to avoid artificial inoculation by resource-poor farmers in Africa. The current selection procedure for enhanced N₂ fixation is based on an assessment of nodule formation which does not directly quantify the proportions of crop N derived from the atmosphere. We have monitored N accumulation patterns and N₂ fixation in nine promiscuous soybean cultivars with different maturity periods, using the ¹⁵N dilution technique. Nodule development generally peaked at the early podfill stage for all cultivars except Tgx 1519-1D and Tgx 1447-2D in which it continued to increase. The proportion of crop N derived from fixation (%NDFA) ranged between 51% and 67%, 77% and 84%, and 66% and 73% at full bloom, early podfill, and physiological maturity stages, respectively. Total N accumulation increased in all soybean genotypes with increasing plant age. Significant correlations (P<0.001) were established between nodule weight and %NDFA, even though this did not explain the relationship between nodule development and N₂ fixation in cultivars such as Tgx 1519-1D. Promiscuous soybean cultivars retained between 10% and 19% of total N accumulated at the final harvest, in belowground biomass. Our results indicated that these soybean cultivars can derive substantial proportions of plant N from N₂ fixation in soils where compatible indigenous bradyrhizobia populations are adequate and effective. Also, we have substantiated the claims that qualitative nodulation parameters currently used to select varieties with a high N₂ fixation capacity need to be validated with other measurements of N₂ fixation. Received: 5 November 1998     

日本血吸虫蛋白质组学研究进展

随着日本血吸虫(Schistosoma japonicum)基因组学的发展,应用双向电泳、质谱分析及生物信息学分析开展的蛋白质组学研究正成为日本血吸虫研究的前沿领域。生物体中的基因是相对稳定,但是蛋白质的活动随着生命活动的进行表现出动态的变化,并具有对外界环境发生反应的能力。对日本血吸虫进行蛋白质组学方面的研究,能直接地反映其生理功能的过程。这些研究为研制开发抗日本血吸虫病疫苗、新型治疗药物提供了新的途径。论文从日本血吸虫童虫部分差异表达蛋白、成虫蛋白质的性别差异性、药物相关蛋白组学、免疫蛋白组学等方面,对日本血吸虫蛋白质组学研究做了概述。     

温度对稻螟赤眼蜂在米蛾卵上的生长发育和寄生潜能的影响

【目的】本研究旨在明确不同温度下稻螟赤眼蜂在米蛾卵上的生长发育状况及寄生潜能。【方法】分别在15℃、20℃、25℃、30℃、33℃下,编制了吉林稻螟赤眼蜂在米蛾卵上的生命表,根据不同温度下稻螟赤眼蜂的发育历期、发育速率计算世代发育起点温度、世代有效积温,并采用线性回归模型对发育速率进行拟合。【结果】稻螟赤眼蜂平均单雌寄生米蛾卵数随着温度的升高呈现先升高后降低的趋势,30℃时最高,达29.75粒,除与25℃下无显著差异外,均显著高于其他温度;雌蜂平均寿命随温度升高而下降,15℃时寿命显著长于其他温度,当温度高于30℃时,其寿命均短于0.82d;25℃时,稻螟赤眼蜂羽化率最高,达98.14%;15℃时,羽化率最低,只有67.96%。稻螟赤眼蜂的发育速率与温度呈显著线性关系,其发育起点温度为11.49℃,世代有效积温为131.39℃·d。【结论】利用米蛾卵繁殖稻螟赤眼蜂时,温度对其有显著影响,综合生命表参数、单雌寄生米蛾卵数、雌蜂寿命、羽化率等指标,提高利用米蛾卵工厂化繁殖稻螟赤眼蜂的最佳温度为25℃~30℃。     

微生物菌肥对普陀樟、红楠2个树种苗木生长及养分状况的影响

为了增强海岛特色树种苗木抗逆性,提高海岛困难地造林成活率,以普陀樟、红楠容器苗为材料,研究不同菌肥及用量对苗木生长、生物量和养分状况的影响。结果表明：不同菌肥及用量通常对普陀樟生长和生物量的积累无明显作用,但可显著促进红楠的高、径生长和生物量的积累,其中应用40、60 g/盆百欧盖恩微生物菌肥,高、径生长量分别提高36.39%、33.76%和17.63%、15.40%,总生物量增加57.04%、56.50%,仅应用含N量较高的菌肥时明显抑制两者生长。菌肥的使用通常有利于促进N、P在普陀樟根、茎的积累,且能较大幅度地提升N、P、K在红楠植株各部位的积累,其中普陀樟应用20、40 g/盆百欧盖恩微生物菌肥,根上的N浓度分别增加13.87%、17.65%,茎、根上的P浓度分别增加13.39%、12.60%和27.29%、11.48%,含量的变化趋势与浓度基本一致;红楠应用40、60 g/盆百欧盖恩微生物菌肥,根上的N浓度分别增加10.53%、27.32%,P浓度分别大幅增加47.78%、70.82%,K浓度分别增加24.74%、35.99%,含量大幅上升。