两株链霉菌对玉米的促生增产作用及机理

为探索娄彻氏链霉菌(D74)和密旋链霉菌(Act12)及其混合菌剂对玉米生长的影响,采用皿内发芽试验、沙培试验及小区试验观察供试链霉菌无细胞发酵滤液及活菌制剂种子包衣对玉米生物学性状、叶片诱导酶活性、光合作用、穗性状、产量及品质的影响.结果表明: 供试链霉菌无细胞发酵滤液处理玉米种子可促进玉米胚根、胚轴及幼苗生长,提高玉米幼苗叶片诱导酶活性.D74发酵液稀释1000倍处理可使玉米胚根长度、胚轴长度及须根数较对照分别增加43.4%、26.4%和100.7%(P＜0.05);D74原液可使玉米叶片多酚氧化酶(PPO)活性较对照增加40.2%.Act12发酵液稀释100倍处理可使玉米胚根长度、胚轴长度和须根数较对照分别增加36.3%、36.3%和117.5%(P＜0.05),玉米幼苗总鲜质量、根系鲜质量分别较对照增加31.1%、36.6%(P＜0.05);Act12稀释10及1000倍处理玉米种子可使玉米叶片PPO活性分别较对照增加38.1%和39.5%(P＜0.05).混合菌剂种子包衣具有以下作用:1)促进玉米根系发育;2)显著增强叶片光合能力;3)显著改善穗性状并提高籽粒产量;4)显著促进籽粒灌浆速度;5)明显提高灌浆期玉米叶片诱导酶活性.表明供试链霉菌制剂包衣玉米种子可显著影响玉米的生物学特性、光合生理及生化代谢,刺激根系发育,促进玉米生长,提高产量.     

Interactions Between Fe(III)-oxides and Fe(III)-phyllosilicates During Microbial Reduction 2: Natural Subsurface Sediments

Dissimilatory microbial reduction of solid-phase Fe(III)-oxides and Fe(III)-bearing phyllosilicates (Fe(III)-phyllosilicates) is an important process in anoxic soils, sediments and subsurface materials. Although various studies have documented the relative extent of microbial reduction of single-phase Fe(III)-oxides and Fe(III)-phyllosilicates, detailed information is not available on interaction between these two processes in situations where both phases are available for microbial reduction. The goal of this research was to use the model dissimilatory iron-reducing bacterium (DIRB) Geobacter sulfurreducens to study Fe(III)-oxide vs. Fe(III)-phyllosilicate reduction in a range of subsurface materials and Fe(III)-oxide stripped versions of the materials. Low-temperature (12 K) Mossbauer spectroscopy was used to infer changes in the relative abundances of Fe(III)-oxide, Fe(III)-phyllosilicate, and phyllosilicate-associated Fe(II) (Fe(II) phyllosilicate). A Fe partitioning model was employed to analyze the fate of Fe(II) and assess the potential for abiotic Fe(II)-catalyzed reduction of Fe(III)-phyllosilicates. The results showed that in most cases Fe(III)-oxide utilization dominated (70–100%) bulk Fe(III) reduction activity, and that electron transfer from oxide-derived Fe(II) played only a minor role (ca. 10–20%) in Fe partitioning. In addition, the extent of Fe(III)-oxide reduction was positively correlated to surface area-normalized cation exchange capacity and the Fe(III)-phyllosilicate/total Fe(III) ratio. This finding suggests that the phyllosilicates in the natural sediments promoted Fe(III)-oxide reduction by binding of oxide-derived Fe(II), thereby enhancing Fe(III)-oxide reduction by reducing or delaying the inhibitory effect that Fe(II) accumulation on oxide and DIRB cell surfaces has on Fe(III)-oxide reduction. In general our results suggest that although Fe(III)-oxide reduction is likely to dominate bulk Fe(III) reduction in most subsurface sediments, Fe(II) binding by phyllosilicates is likely to play a key role in controlling the long-term kinetics of Fe(III) oxide reduction     

First direct resolution of gossypol enantiomers on a chiral high‐performance liquid chromatography phase

The first direct resolution of gossypol enantiomers has been achieved by HPLC on a chiral stationary phase consisting of cellulose tris‐(3,5‐dimethylphenyl carbamate) coated onto microporous aminopropyl‐silica eluted in the reverse phase mode. Chirality 11:46–49, 1999. © 1999 Wiley‐Liss, Inc.     

Use of cheese whey as a substrate to produce manganese peroxidase by Bjerkandera sp BOS55

Manganese peroxidase, MnP, is one of the major ligninolytic enzymes produced by a number of white-rot fungi. The ability of this enzyme to degrade lignin by the fungus Bjerkanderasp BOS55 has opened its application to related bioprocesses such as recalcitrant-compound degradation and effluent decolorization. The medium reported to induce MnP production is composed of chemical grade reagents, all with relatively high costs for application to detoxification purposes. The use of inexpensive sources for MnP production can bring its implementation closer. For this purpose, dairy residues from cheese processing were considered. MnP production obtained using crude whey as the sole substrate reached appreciable levels, around 190 U L⁻¹, values comparable to those found with synthetic media (between 175–250 U L⁻¹). Thus, this cheese-processing byproduct can be used as an inexpensive alternative for the large-scale production of MnP. Received 14 December 1998/ Accepted in revised form 29 April 1999     

一种简易的免疫PCR方法的建立

免疫PCR为一种高敏感度检测抗原的新技术,操作程序大多沿袭ELISA方法.用戊二醛作连接剂,将蛋白质高效率包被在普通PCR管内壁,使免疫及PCR反应用普通PCR仪得以在管中连贯地进行.实验结果表明,标准曲线的线性关系好,与ELISA方法比较敏感度高出约10⁵.这一改良法的建立,可望促进免疫PCR的普及应用.     

添加天然防腐剂的涂料在水果保鲜贮藏中的应用

系统跟踪研究了经保鲜处理的果品在贮存期间的生理活动和商品性能的变化 ,证实在保鲜涂料中添加天然防腐剂在失重率、烂果率、性状风味、VC 含量等指标上均优于化学防腐剂 ,为应用该天然保鲜涂料提供了依据。     

微生物除Mn(Ⅱ)机制及影响因素研究进展

锰是生物所必需的一种微量元素,但工业技术发展以及矿产资源的开发导致大量的Mn(Ⅱ)排放进入环境中对人体健康产生严重威胁.微生物修复技术可快速高效去除环境中的Mn(Ⅱ),且无二次污染,成为近年研究的热点.本文综述了除Mn(Ⅱ)微生物的种类与分布及其除Mn(Ⅱ)的机制,总结了影响微生物除Mn(Ⅱ)的因素,并展望了除锰微生物...     

The White-Rot Fungus Pleurotus ostreatus Transformant Overproduced Intracellular cAMP and Laccase

Transformation of Pleurotus ostreatus PC9 with the mutated heterotrimeric G protein alpha subunit (Gα) gene resulted in higher laccase (Lac) activity and intracellular cyclic adenosine monophosphate (cAMP) concentrations as compared to those in wild-type PC9. The transformant also exhibited higher Lac activity than the wild type when cultured in a medium containing known Lac inducers CuSO₄ and ferulic acid.