氧化铁鞘细菌铁氧化酶最适产酶条件及其酶学特性的研究

对氧化铁鞘细菌FC990 1菌株的铁氧化酶最适产酶条件及酶学特性进行了研究。菌株最适产酶培养基为 (g/L) :柠檬酸铁胺 10g ,NaNO3 1.2g,MgSO4·7H2 O 0 .5g ,K2 HPO4·7H2 O 0 .5g ,CaCl2 0 .0 15g ,ZnSO4·7H2 O 0 .0 0 0 5g。最适产酶条件为 :温度 30℃ ,起始pH7.0 ,接种量 2 % ,15 0mL三角瓶装 5 0mL ,15 0r/min振荡培养 72h。铁氧化酶最适pH为7.5 ,最适温度为 30℃。金属离子Ca2 、Mg2 、Zn2 对酶有激活和稳定作用 ;Cu2 、Hg2 、Al3 则抑制酶的活性 ;Fe2 、K 、Na 对酶活性影响不明显。     

高温蛋白酶产生菌的筛选及其产酶条件和酶学性质分析

从徂徕山温泉附近土样中分离到9株产高温蛋白酶菌株,选取一株碱性蛋白酶高产菌株L7为出发菌株,进行显微形态、16S rRNA基因序列分析,将其初步鉴定为短芽孢杆菌(Brevibacillus sp.)。研究该菌株发酵条件,确定产酶的最佳培养基组成为葡萄糖40 g/L,蛋白胨20 g/L,磷酸氢二钠1.4 g/L,氯化钙0.6 g/L,硫酸镁0.4 g/L,通过培养基优化,酶活达到103.08 U/mL。最佳培养条件为250 mL三角烧瓶中装液量50 mL、pH8.0、培养温度为55℃、培养时间为24 h。对该菌株酶学性质研究,L7菌株所产高温蛋白酶的最适温度为55℃,最适pH为10,并且具有良好的温度稳定性和pH稳定性,酶活性受PMSF强烈抑制。     

4-氯乙酰乙酸乙酯羰基还原酶产生菌的筛选及产酶条件研究

从实验室保藏的菌株中,筛选到一株立体选择性较高的产4-氯乙酰乙酸乙酯(COBE)羰基还原酶的菌株———出芽短梗霉(Aureobasidiumpullulans)SW0202,菌体产酶条件研究表明,最佳的发酵培养基配方为:麦芽糖30.0g/L,酵母膏20.0g/L,蛋白胨3.0g/L,(NH4)2SO45.0g/L,KH2PO42.0g/L,MgSO4.7H2O0.7g/L,最适发酵温度及初始pH分别为:28°C和pH6.0。该菌在此条件下发酵培养24h,产菌丝体生物量16.78g干菌体/L,COBE羰基还原酶酶活力达到1007U/L。在COBE的转化反应中,产物S-CHBE的浓度达到10.12g/L,光学纯度>97%e.e.。     

产漆酶菌株分离及发酵条件优化

[目的]筛选高产漆酶菌株。[方法]利用愈创木酚-PDA平板筛选高产漆酶菌株,单因素实验确定最佳产酶条件。[结果]筛选到一株高产漆酶菌株,编号QMJZ-5。结合形态观察和5.8S rDNA-ITS序列分析,确定该菌株是血红密孔菌(Pycnoporus coccineus),优化发酵培养基:甘油20 g/L,豆粕6.0 g/L,香兰素0.15 g/L,阿魏酸0.15 g/L,KH_2PO_41.0 g/L,Na_2HPO_4·12H_2O 0.2 g/L,CuSO_4·5H_2O 1.5 mmol/L,初始pH 5.0,30℃,发酵8 d,产酶55 U/m L。[结论]筛选到1株高产漆酶菌株。     

α-氯丙酸脱卤酶发酵条件研究

以从厌氧污泥中分离筛选获得的对α-氯丙酸有高效脱卤能力的微生物菌株W20为出发菌株,对其发酵生产脱卤酶的工艺进行了研究。其产脱卤酶培养基组成为:葡萄糖20.0 g/L,尿素1.0 g/L,酵母膏0.5 g/L,Na2HPO4.12H2O 3.2 g/L,KH2PO41.5 g/L,无水MgSO40.098 g/L,微量元素液10 mL/L,维生素溶液5.0 mL/L。产酶条件为:接种量10%,培养基初始pH7.0,培养温度30℃,装液量80 mL/250 mL摇瓶,摇床转速180 r/min。在以上获得的培养基和培养条件下培养48 h后测酶活,脱卤酶活力达到8.76 U/g干菌体,比在原始条件下提高约10倍。     

产弹性蛋白酶菌种的筛选及发酵条件优化研究

从合肥肉联厂附近的土壤和污水中分离得到19株产弹性蛋白酶菌株,初步鉴定该菌株属于假单胞菌属.经过发酵复筛有三株产酶能力超过15u/mL.实验对菌株最佳产酶发酵条件进行了优化2%干酪素、0.5%葡萄糖、0.4%酵母膏、0.2% K2HPO4、0.01% MgSO4·7H2O;起始pH值7.0;最适发酵温度为30℃;装液量为25mL/250mL;该菌株在28h左右产弹性蛋白酶的量达18u/mL.     

茶树内生真菌CSN-4产漆酶培养基及培养条件研究

从茶树内生真菌筛选产漆酶的菌株,分析不同营养因素和培养条件对菌株漆酶酶活力的影响。采用6种显色底物的平板初筛和酶活测定的复筛方法,从15株茶树内生真菌菌株中筛选获得1株产漆酶酶活较高的菌株CSN 4。单因素分析结果显示,液态发酵条件下菌株CSN-4适宜的主要培养基成分是麸皮和蛋白胨;菌株CSN-4分别在麸皮30 g/L、蛋白胨2.5 g/L、CuSO₄·5H₂O 0.015 g/L和茶水6 g/L时发酵产漆酶酶活最高。发酵条件试验结果表明,菌株CSN-4分别在接种量为6个菌饼（直径6 mm）、装液量60 mL/250 mL、pH 4.8、摇床转速120 r/min,培养温度为28 ℃时产漆酶酶活较高。在培养基中添加麸皮和茶水对菌株CSN-4产漆酶有明显的促进作用。经过培养基成分及培养条件优化后,菌株CSN 4产漆酶酶活显著升高,达到2 417 U/L。     

对映选择性Geotrichum sp. GXU33脂肪酶的筛选、产酶及酶学性质研究

利用溴麝香草酚蓝作为反应指示剂,快速地筛选到产对映选择性脂肪酶菌株GXU33(Geotrichum sp.),此酶能够拆分外消旋扁桃酸甲酯产生(S)-扁桃酸.此菌株最适生长、产酶条件为橄榄油 10 g/L, 酵母粉 5 g/L, Na2HPO4·12H2O 3.5 g/L, KH2PO4 1.0 g/L, MgSO4·7H2O 0.2 g/L, pH 7.0,28℃,200 r/min.PMSF和蛋白酶K对菌株生长没有影响,PMSF显著抑制酶活,蛋白酶K具有保护酶活力的作用.该脂肪酶最适作用pH 为7.5,最适作用温度为30 ℃; Ca2 ,Mg2 ,Zn2 不同程度提高酶活性,Cu2 , Co2 ,Mn2 ,Fe2 ,Fe3 严重抑制酶活性.当以5% DMSO为助剂,消旋扁桃酸甲酯20 mg,GXU33 脂肪酶1500 U,25 mmol/L磷酸钠缓冲液(pH 7.5)加至总体积2 mL,32 ℃,100 r/min, 反应8h,得到最佳拆分效果:转化率为44.8%,(S)-扁桃酸对映过量值为83.5%.     

均匀设计法优化烟管菌产漆酶培养基

应用均匀设计、二次多项式逐步回归分析对烟管菌(Bjerkandera adusta)WZFF.W-Y11产漆酶液态发酵培养基进行优化。结果表明,培养基组成为麸皮水解液1%、淀粉24.0g/L、葡萄糖24.0g/L、豆饼粉4.8g/L、NH4Cl3.2g/L、KH2PO43.2g/L、MgSO4.7H2O0.2g/L、CuSO4.5H2O0.006g/L,起始pH6.5,在28℃、150r/min、250mL的摇瓶培养条件下可以稳定地获得9672U/L的漆酶活力。     

响应面法优化革耳Panus rudis FG-35菌株产漆酶培养基

采用Plackett-Burman设计和响应面分析相结合的方法,对革耳Panus rudis FG-35菌株产漆酶的液体培养基配方进行优化。单因素试验结果显示,发酵培养基中的最优碳源为可溶性淀粉,最优氮源为蛋白胨;Plackett-Burman设计筛选出影响漆酶产量的3个重要因素为可溶性淀粉、金属Ca2+离子和吐温-40,在此基础上运用最陡爬坡试验逼近最大响应值区域,最后利用Box-Behnken试验设计及响应面分析法进行回归分析,获得最佳培养基配方为:可溶性淀粉10.040 4 g/L、蛋白胨0.2 g/L、K2HPO41.00g/L、ZnSO4·7H2O 0.008 g/L、MgSO4·7H2O 0.5 g/L、CuSO4·7H2O 0.007 g/L、FeSO4·7H2O 0.005 g/L、MnSO40.035 g/L、CaCl20.0816 g/L、VB10.1 g/L、吐温-40 0.428%。在优化后的条件下摇瓶发酵产漆酶酶活力为263.31 U/mL,与模型预测值接近,发酵产酶量比优化前提高1.07倍,同时优化后的发酵液对木质素降解进行试验发现,优化后漆酶对木质素降解率提高了14.34%。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.