用于提取可纺性竹原纤维菌株的选育

从自然界腐朽的竹材或木材中,能分离和筛选高效降解木质素并只少量降解或者不降解竹纤维的优良菌株,通过GU-W A平板变色反应试验和菌株对竹材木质素、竹纤维降解试验,共获得了3株具有选择性降解竹木质素的优良菌株(15、18、21号菌株),经初步鉴定这3株菌为真菌菌株;测定了菌株在摇瓶培养时所产孢外酶的酶活.最后采用3株菌联合法进行降解竹材木质素试验.结果表明:3株菌联合降解木质素效果优于单一菌株,其降解率可达72.26%.     

[14C]Dicofol association to cellular components of Azospirillum lipoferum

The bacterium Azospirillum lipoferum is able to survive in high concen-trations of the organochlorine acaricide dicofol [1,1-bis-(4-chlorophenyl)-2,2,2-trichloroethanol]. It accumulates this chemical in the cell envelope where it is protected against hydrolysis. We investigated the nature of cell envelope molecules with which [¹⁴C]dicofol is associated; no indication of [¹⁴C]dicofol–saccharide bonds was found. We concluded that about 80% of the total [¹⁴C]dicofol found in the cells was associated with lipids and the remaining 20% with proteins. Electrophoresis did not indicate any correlation of a specific protein band with [¹⁴C]dicofol radioactivity peaks. After Folch partition, [¹⁴C]dicofol distribution in TLC analysis showed 60% of [¹⁴C]dicofol–lipid bonds related to neutral lipids, 20% to phospholipids and the remaining 20% of the bonds associated with other lipids. Experimental results suggested that [¹⁴C]dicofol associates mainly with membrane domains near proteins and that this association influences membrane fluidity as well as enzymatic activity. © 1998 SCI     

兽医微生物学教学实践与思考

根据兽医微生物学课程的性质和特点,结合多年教学经验,坚持以学生为本,在常规教学方法的基础上,对兽医微生物学的理论和实验教学方法进行探索和尝试,以期提高兽医微生物学教学质量,为培养高素质人才奠定基础。     

基于高通量测序技术的燕窝罐头腐败嗜热菌分析

为了研究燕窝罐头生产过程微生物结构的变化,同时筛查出造成燕窝罐头安全隐患的嗜热微生物,该研究通过16S rRNA高通量测序技术结合传统培养分离方法研究燕窝生产中燕窝原料、冰糖原料、蒸煮锅糖液、灌装车间毛巾、灌装口糖液、挑毛车间毛巾、汽蒸后燕窝、灌装后产品的微生物组成.Alpha多样性研究结果表明灌装工序是微生物可能显著...     

C and N stocks are not impacted by land use change from Brazilian Savanna (Cerrado) to agriculture despite changes in soil fertility and microbial abundances

Central Brazil is the region with the most dynamic agriculture expansion worldwide, where tropical forests and Cerrado (Brazilian savanna) are converted to pastures and crop fields. Following deforestation, agricultural practices, such as fertilization, tillage and crop rotations, alter soil parameters and affect microbial abundances and the C and N cycles. The objective of this study was to compare changes in soil fertility, stocks of soil C and N, microbial biomass, and abundance of bacteria, fungi and archaea in Cerrado soils following land use change to crops (soybean/corn/cotton) and pasture (the perennial forage grass Brachiaria brizantha A. Rich.). Agriculture increased soil fertility and conserved soil C and N since their absolute concentration values were highest in agriculture soils and the C and N stocks adjusted by soil density were similar to the native vegetation soils. At the same time, agriculture changed the microbial abundances (decrease of microbial biomass C and N, increase of archaea, and reduction of bacteria and fungi at the crop sites), and N dynamics (increase of soil ammonium and nitrate concentrations). Even if these changes can be beneficial for food and agricultural commodities production, all these soil alterations should be further investigated due to their possible unknown effects on biosphere–hydrosphere–atmosphere exchange processes such as greenhouse gases emissions and nitrate leaching.     

多媒体教学在“畜牧微生物学”课程中的应用

介绍了＂畜牧微生物学＂多媒体教学课件的制作、使用、日常更新与维护,并提出了及时优化教学内容、注意讲授节奏、及时与学生沟通、摆脱计算机束缚及灵活应用多媒体课件等注意事项。     

Wheat growth promotion through inoculation with an ammonium-excreting mutant of <Emphasis Type="Italic">Azospirillum brasilense</Emphasis>

Azospirillum brasilense is a diazotrophic bacterium and one of the best studied plant-growth-promoting bacterium living in close association with several agronomically important crops. The production of plant-growth-regulating substances is a main mechanism of plant growth stimulation, although other mechanisms have also been proposed. Nitrogen transfer from the bacterium to the plant is one among the other possible mechanisms of plant growth stimulation. In this study, we investigated, by means of a greenhouse trial with winter wheat inoculation, the effect of a point mutation in the ammonium binding site of the A. brasilense glutamine synthetase. The glutamine synthetase is one of the main ammonium-assimilating enzymes and mutations in this enzyme generally result in the release of ammonium from the bacterium to its environment. The ammonium-excreting mutant used in this study was shown to perform better than the wild-type A. brasilense strain with respect to wheat growth parameters and yield. In the greenhouse conditions used, this effect was independent of the way fertilizer was applied. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.