广西北海红树林土壤放线菌的分离与鉴定

[目的]鉴定广西北海红树林土壤放线菌的物种多样性.[方法]从广西北海红树林土壤中分离、筛选10株典型放线菌菌株,提取基因组DNA,进行16S rDNA PCR扩增与测序,并构建进化树.[结果]通过Blast比对,10株放线菌属于2个属,其中8株为链霉菌属(80%),2株为拟诺卡氏菌属(20%).[结论]广西北海红树林土壤蕴减着种类丰富的放线菌. Abstract： [Objective] The aim was to identify the species diversity of Actinomycetes from Mangrove forest in Beihai,Guangxi Province.[Method]10 strains of typical Actinomycetes were isolated from Mangrove forest soil,and the Actinomycetes genomic DNA was successful extracted.16S rDNA was amplified by PCR and sequenced by Sanger dideoxy sequencing method.[Rcsult]All the sequences were blasted in genbank,eight strains belonged to the genus of Streptomyces (80%),and two strains belonged to the genus of Nocardiopsis (20%).[Coacluslon]There are many different Actinomycetes species in Mangrove forest soil samples in Beihai,Guangxi Province.     

正则Markov链的收敛与逼近

研究Markov链中概率转移函数的收敛性,用算子半群的方法证明了正则概率转移函数的收敛与其对应的预解函数的收敛等价,并给出了概率转移函数收敛的q-矩阵条件.

Abstract：

This paper discusses the convergence and approximation in Markov chains by employing operator semigroup method.It is showed that if the Markov chains are regular,then the convergence of a sequence of transition functions is equivalent to the convergence of the corresponding resolvent functions.Furthermore,a condition on qmatrices such that their corresponding Q-functions converge is also obtained.     

Partial Characterization of Chitinolytic Extract from Endophytic Streptomyces sp. and Its Effects on the Boll Weevil

The present study achieves the biochemistry partial characterization of the chitinolytic extract produced by an endophytic Streptomyces sp. strain （A8）. This extract was also tested against Anthonomus grandis, the cotton boll weevil aiming its control. The chitinase crude extract from the A8 strain was cultured for five days in a minimum liquid media supplemented with chitin. The extract was partially characterized by standard methods. The chitinolytic extract had an optimum temperature of 66 ＂C and an optimum pH between 4 to 9 （around 80% of relative activity）. We also characterized the temperature and pH stability and measured the effects of enzyme inhibitors. The filtered chitinolytic extract was added to an artificial boll weevil diet. Boll weevil development from the egg stage to the adult stage was prolonged, and the percentage of adults that emerged was approximately 66% less than on control diet. This study showed that the.larval development of A. grandis was inhibited by the presence of characterized chitinolytic extract in artificial diet. This work provides an experimental basis for using the chitinase from an endophytic bacterium Streptomyces sp. as a biocontrol alternativeto controlling the plant pest A. grandis.     

链霉菌702所产抗真菌活性物质稳定性研究

通过试验对链霉菌702发酵液可能存在的理化性质进行了简单探讨。结果表明,该抗真菌成分具有较高的热稳定性,在酸性、中性环境下比较稳定,在碱性环境下不稳定;对紫外线不稳定,照射30 min,其抑桔青霉活性为零。     

微生物检测法测定安来霉素发酵液生物效价

根据安来霉素对革兰阳性细菌能产生有效抑制的原理,采用微生物抑制法试验,做出抑菌圈直径对应安来霉素效价的标准曲线。试验以枯草芽孢杆菌为工作菌,用杯碟法测定安来霉素的效价。结果表明:标准曲线的工作范围为1700～1.33万μg/mL,安来霉素的最低检出限为21.47μg/mL,平均回收率均超过97.5%,并且检测时间仅需16h。该法能快速检测安来霉素效价且灵敏度高,操作简便,回收率高。     

具有抗菌活性红树林土壤放线菌BH0951的分离和鉴定

以广西北海红树林高盐泥样为材料,采用高氏1号培养基对其中的菌株进行分离纯化,通过抗菌试验筛选出1株放线菌BH0951,该菌株的发酵产物具有较强的抗菌活性,其最适生长温度为28℃,最适生长pH值为7.0。提取其总DNA,采用通用引物对其16S rDNA进行PCR扩增,并对扩增产物进行序列测定。结果表明,BH0951为链霉菌属（Streptomyces aurantiogriseus）AY999773的变种。     

中国奶农处境最不利

缺乏完整的生产加工链 从内部保护方面,世界其他国家奶业生产链条一般都采取合作社的生产方式,只有奶农才能够入股,而且这种合作社式的企业也不用纳税,所有的利润都返回到奶农。     

泰山广翅目昆虫记述

本文记述了分布于泰山的2种广翅目(Megaloptera) 昆虫,即小碎斑鱼蛉(Neochauliodes sparsus Liu et Yang)和炎黄星齿蛉(Protoheres xanthodes Nava′s),分别描述了其形态特征.     

乌鳢免疫球蛋白M重链和免疫球蛋白轻链的克隆与特征分析

应用RACE-PCR方法克隆并鉴定了乌鳢免疫球蛋白M(i mmunoglobulin M,Ig M)重链(H)和免疫球蛋白轻链(L)全长cDNA。乌鳢IgH cDNA全长1 912个核苷酸(nt),包含1 797 nt的开放阅读框,编码598个氨基酸(aa)。IgH恒定区(CH)均包含1对保守的半胱氨酸残基形成链内二硫键,其中CH1区氨基末端存在保守的半胱氨酸残基与轻链形成链间二硫键,4个推测的N-糖基化位点(NXT和NXS)则分别位于CH1、CH2和CH4。序列比对发现乌鳢IgHCH1与CH2交界处氨基酸序列的插入使铰链区肽段较其他硬骨鱼IgH长,此外IgH CH4区羧基末端参与单体间聚合的半胱氨酸被赖氨酸替换,这反映乌鳢IgH分子结构的特异性。序列相似性比较显示乌鳢IgH与点带石斑鱼、黑鳍冰鱼、牙鲆、虹鳟的相似性依次为55%、50%、45%和36%,与斑马鱼类的相似性较低(为28%)。乌鳢IgL cDNA全长941 nt,包含729 nt的开放阅读框,编码242个aa。轻链可变区(VL)和恒定区(CL)均包含保守的半胱氨酸,形成链内和链间二硫键。序列比对分析表明乌鳢IgL与五条鰤和花狼IgL的相似性为78...     

山东链霉菌抗菌素对大棚番茄、黄瓜病害的防治及增产试验

对山东链霉菌抗菌素进行了大棚黄瓜霜霉病、白粉病及番茄立枯病、猝倒病防治试验,并测定其增产效果。结果表明：其对黄瓜霜霉病、白粉病4点平均防效分别为76.3%和83.8%;对番茄立枯病、猝倒病防效分别为74.6%和70.2%;增产效果分别为黄瓜54.2%（生长期施药）和番茄14.1%（苗期施药）;外观表现为叶色浓绿,生长旺盛,果实收获期可提前2～3天。