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地址:湖南省长沙市芙蓉区马坡岭省农科院试验大楼湖南省农业信息与工程研究所 《Agricultural Science & Technology》(《农业科学与技术》)编辑部(邮编 410125)
The culture of Magnetospirillum magneticum WM-1 depends on several control factors that have great effect on the magnetic cells concentration. Investigation into the optimal culture conditions needs a large number of experiments. So it is desirable to minimize the number of experiments and maximize the information gained from them. The orthogonal design of experiments and mathematical statistical method are considered as effective methods to optimize the culture condition of magnetotactic bacteria WM-1 for high magnetic cells concentration. The effects of the four factors, such as pH value of medium, oxygen concentration of gas phase in the serum bottle, C:C (m_(tartaric acid): m_(succinic acid)) ratio and NaNO_3 concentration, are simultaneously investigated by only sixteen experiments through the orthogonal design L16(4~4) method. The optimal culture condition is obtained. At the optimal culture condition ( pH 7.0, an oxygen concentration 4.0%, C: C (m_(tartaric acid):m_(succinic acid)) ratio 1:2 and NaNO_3 100 mg l~(-1)), the magnetic cells concentration is promoted to 6.5×10~7 cells ml~(-1), approximately 8.3% higher than that under the initial conditions. The pH value of medium is a very important factor for magnetic cells concentration. It can be proved that the orthogonal design of experiment is of 90% confidence. Ferric iron uptake follows Michaelis-Menten kinetics with a K_m of 2.5 μM and a V_(max) of 0.83 min~(-1).
香菇Lentinula edodes AX3及五种霉菌于木质纤维素基质中液体浸没培养,检测了其胞外滤液的羟自由基(·OH)清除能力。结果表明:仅L.edodes AX3发酵液具有显著的·OH清除能力,其在第48h左右清除率达峰值52.2%;五株霉菌在试验条件下基本均不能清除·OH。·OH清除能力与菌株的木质纤维素降解模式及能力相关。适应于木质素降解自由基链式反应的·OH 胁迫压力,白腐菌形成了胞外·OH 清除能力,其物质基础源于白腐菌对木质纤维素的降解与转化产物。
In this study, three methods such as CTAB,SDS and Shanlichun methods were used to extract genomic DNA from the seedling of rape to find the best method. The principle, characters and application of SRAP were introduced. In order to obtain the optimal SRAP reaction system, the factors including concentrations of DNA, dNTP, etc. of reaction system were modified to better the system of rape. The result showed that the optimum concentrations were15ng DNA template, 0.2mM dNTP, 1.0μM primer and 2.0U Taq enzyme in this 25μL SRAP-PCR system.
天麻是无根、叶的兰科植物,土中的块茎靠蜜环菌供给养料,其栽培关键是良种、优菌、凉爽、湿润。以活性成分1~10克/日的用量将其用于镇痛、抗惊厥(对照是甲基多巴,0.5~2.0克/日),临床研究表明:天麻能明目、降血压、缓心率、增加心输出量;天麻蜜环菌片可治疗神经衰弱、高血压、冠心病所致的头晕、头痛、心绞痛等症,有效率达80%以上。并指出繁育优质种源利于提高天麻产量并保持药性。
<正>Viruses are considered the most important constraint to hot and sweet pepper (Capsicum sp.) production in China, from which nine viruses have
<正>《农业科学与技术》(Agricultural Science & Technology)是国家科技部批准,湖南省农科院与国家杂交水稻工程技术研究中心主办,国内外公开发行