日本血吸虫非叉型尾蚴感染动物试验

试验采集云南巍山地区自然条件下的钉螺,压碎钉螺、检获尾蚴,发现为非叉型尾蚴。将非叉型尾蚴400~850条/只经皮肤感染家兔,同时,用云南洱源的叉型尾蚴作对照试验。感染后50～55 d解剖兔子,试验组检获到日本血吸虫,荷虫量为10～15条/只。试验结果表明,云南巍山非叉型尾蚴能感染动物,该试验结果为丰富日本血吸虫的生活史提供了极有价值的补充。     

中国家畜血吸虫病防治

本文对家畜血防在中国血吸虫病防控中的作用与地位、家畜/农业血防发展历程以及中国血吸虫病防治科研进展、面临的主要难点与挑战等方面进行了论述,并对今后家畜血防工作提出了建议。     

天竺桂果实色素薄层成分分析

通过薄层层析方法分析出天竺桂果实色素的化合物,再通过紫外光谱仪分析方法鉴定出有效成分。用不同极性的溶剂,不同配比作展开剂进行最佳展开剂试验,结果表明无水乙醇∶水∶盐酸(5∶1∶1,V/V)为最佳展开剂。薄层层析只分离出一种黄绿色的色素类化合物,其Rf值为8.3。其紫外可见吸收光谱显示出类胡萝卜素的特征吸收,初步判定该色素类化合物为β-胡萝卜素。     

连香树种子大小分布及其变异研究

研究了茂县山地生态系统定位研究站人工连香树种群个体种子大小分布及变异。结果表明,连香树种子大小分布呈正态分布,种子大小为(0.4±0.1)mg,其变化范围为0.1~1.2 mg;连香树个体间种子大小存在明显的差异,变异幅度较大,变异系数为31.8%;种子大小变异可能来源于个体间。     

NaCl胁迫对普陀樟叶绿素荧光参数的影响(英文)

[Objective] Study on the changes of chlorophyll fluorescence parameters in Cinnamomum japonicum var. chenii under NaCl stress. [Method] The seedling growth increment,chlorophyll content and chlorophyll fluorescence parameters in leaves of 1-year old Cinnamomum japonicum var. chenii were investigated in field experiment. [Result] Under NaCl stress,seedling growth increment reduced and the chlorophyll content decreased to a stable value; changes of Fv/Fm and Fv/Fo showed identical increasing trend and double peak type. With the aggravation of salt stress,most variations were observed in Fo,correlations among chlorophyll fluorescence parameters presented "rise-drop" trend (in the treatment of 7 g/L NaCl). [Conclusion] Cinnamomum japonicum var. chenii is endowed with strong salt resistance and wide adaptability.     

Inhibition of growth of Bradyrhizobium japonicum bacteroid by spermidine and spermine in yeast extract

Abstract

Bacteroids are defined as the symbiotic forms of Rhizobium or Bradyrhizobium cells in the root nodules of their legume host. The differentiation to bacteroids involves various physiological changes and may be associated with some genetical changes. Single-colony isolates from a nodule formed by a Bradyrhizobium strain often differed in their effectiveness and intrinsic antibiotic resistance (Weaver and Wright 1987; Ozawa unpublished data). Detailed analysis of the changes in the gene structure requires the isolation of individual bacteroids from a nodule. However it has been reported that the viability of bacteroids in culture is very low and only a small fraction of a bacteroid population could produce colonies on yeast extract-mannitol (YEM) agar (Sutton et al. 1977). Bergersen (1974) concluded that the reversion of bacteroids to the vegetative, growing form is very rare.     

Isolation of transposon Tn5-induced hydrophobic mutants of a Bradyrhizohium japonicum strain with improved competitive nodulation abilities

Abstract

Hydrophobic mutants of the Bradyrhizohium japonicum strain 138NR were obtained by transposon Tn5 mutagenesis followed by replica-plating on polystyrene plates. Fifteen mutants were isolated at a frequency of 10⁶. Gel-filtration analysis of the exopolysaccharides revealed that the hydrophobic mutants produced a significantly smaller amount of low-molecular-weight polysaccharides than the parent. Four of the isolated mutants formed a larger number of nodules on soybean (Glycine max L. Merr. cv. Tamahomare) than the parent, two were superior in symbiotic nitrogen fixation, and two were symbiotically defective on soybean. Competitive nodulation abilities of the mutants were examined by inoculating them to soybean with B. japonicum strain 123ET as a competitor and determining the nodule occupancy based on the antibiotic resistance. All the mutants tested except for the symbiotically defective ones were superior in their competitive nodulation ability to the parent strain. When inoculated 24 h before the inoculation with 123ET, the mutants exhibited an increased nodule occupancy (44–93% compared to 9% by the parent).     

海金沙内生真菌多样性的研究

试验从海金沙的根、茎、叶器官中分离获得了内生真菌17株,鉴定出16株,另外1株因不产孢子而未被鉴定出,分别属于3个纲4个目5个科8个属.在鉴定的8属内生真菌中,以青霉属为优势属,占总株数的23.5％,其次是顶枝孢属和链格孢属,各占总株数的17.6％.表明海金沙不同部位、不同季节内生真菌的数量、分布、种群及其组成存在差异,体现了内生真菌生态分布的多样性.     

不同居群连香树种子形态变异及其与环境因子相关性分析

分析不同居群连香树种子形态变异及其与环境因子相关性,结果表明:不同居群间种子长宽、种翅长宽和千粒重均存在显著差异,按大小排序均为白龙江种>药山种>美姑种,种子形态与纬度、气温、海拔、降水等环境因子之间有显著关系,且呈现较好的稳定性。     

日本血吸虫病的综合防治与公共卫生安全

日本血吸虫病是由日本血吸虫引起的人兽共患传染性疾病。该病呈世界性分布,给我国造成了较大的经济损失,具有重要的公共卫生和社会经济意义,是我国重点防治的寄生虫病之一。从病原、流行病学、诊治等方面进行了阐述,以期为该病的科学防治提供参考依据。