雅致枝霉TE7-15发酵生产γ-亚麻酸的实验研究

研究了温度、时间、碳源和氮源对雅致枝霉诱变株TE7- 15的菌体生长、油脂积累及GLA合成的影响 ,确定了TE7- 15菌株适宜的摇瓶发酵培养条件 ,使其菌体生物量达到 19 0 4g/L ,GLA产量达到10 79 95mg/L ,可以满足工业化生产的要求     

雅致枝霉TE7-15发酵生产γ-亚麻酸的实验研究

研究了温度、时间、碳源和氮源对雅致枝霉诱变株TE7-15的菌体生长、油脂积累及GLA合成的影响,确定了TE7-15菌株适宜的摇瓶发酵培养条件,使其菌体生物量达到19.04g/L,GLA产量达到1079.95 mg/L,可以满足工业化生产的要求.     

激光诱变选育高产PUFAs真菌菌株的研究

采用PIV400型Nd：YAG激光器,对少见报道的产PUFAs丝状真菌菌株Monoblepharis polymorpha Comu进行激光诱变育种。在激光照射剂量：波长532nm,功率50mW,时间10min下,孢子致死率为75％-80％。突变株中w-3系列PUFAs正突变率大于80％,w-3系列突变株FPAm59传代10代以上性能稳定,在土豆基质上摇瓶培养6d后,生物量达到8g/L,产油率53．4％,GLA343．1mg／L、从1209．0mg／L、EPA125．1mg／L、DHA119．4mg／L;分别比对照菌株提高了2．5倍、9．7倍、18．0倍、6．6倍、10．3倍、3．8倍。结果表明,激光诱变育种是获得PUFAs高产菌株尤其是生产w-3系列PUFAs菌株的有效方法。     

解脂耶氏酵母诱变育种及发酵产α-酮戊二酸条件优化

对具有发酵产α-酮戊二酸能力的解脂耶氏酵母(Yarrowia Lipolytica)ZY-4进行了紫外诱变和NTG诱变育种,筛选得到产量提高的突变株,并对突变株的发酵培养基进行了优化,结果表明,紫外诱变和NTG诱变后筛选到的突变株分别比原始出发菌株产量提高了67.8%和110%。优化后发酵培养基成分为甘油8%,氯化铵5.0 g/L,硫胺素1.0μg/L,磷酸二氢钾1.0 g/L,七水硫酸镁0.5 g/L,培养基优化后α-酮戊二酸产量比原始出发菌株提高了232.4%。     

产赤藓糖醇菌种的诱变育种

以耐高渗酵母为出发菌株,采用紫外线诱变处理,得到了一株变异株C1。其摇瓶发酵产赤藓糖醇24．9g／L左右。通过摇瓶发酵试验,研究了菌株C1的遗传稳定性。研究结果表明,经多次传代实验,菌株C1的发酵产糖醇能力没有改变,表明其是稳定的变异株。赤藓糖醇的产量由诱变前的12、594g／L提高到24.943g／L,提高了98.1％。关键词：     

直接利用糖质原料生产L-苹果酸菌种的选育

从土壤中筛选到一株产L－苹果酸的黄曲霉菌,经紫外线、亚硝基胍（NTG）、硫酸二乙酯（DES）和^60Co辐射等诱变处理,并经多次分离得到一株性能稳定的高产L－苹果酸突变株黄曲霉HA5800,35℃,200r/min摇瓶发酵120h,产L－苹果酸72g/L、糖酸转化率为74．22％,经山东省卫生防疫站检定,该菌株不产黄曲霉素素B1。     

产耐高温谷氨酰胺转胺酶菌株的快速筛选方法

目的:采用亚硝基胍(NTG)诱变结合96孔板高通量筛选方法筛选产耐高温谷氨酰胺转胺酶(MTG)的茂原链霉菌(Streptomyces mobaraensis)。方法:通过优化96孔板高通量测定MTG活性的方法、确定筛选温度和时间,建立了产耐高温MTG菌株的快速筛选方法;通过优化NTG诱变条件建立了筛选突变库;通过96孔板高通量初筛、摇瓶复筛获得了产耐高温MTG的突变株12-82,并通过摇瓶发酵对12-82所产MTG进行热稳定性分析。结果:采用2mg/ml NTG、p H8.0、60min的诱变条件获得突变株,将突变株的发酵上清液于70℃水浴7.5min,再在37℃空气浴、反应10min的条件下测定MTG活性,从5 200株突变株中筛选出5株产耐高温MTG的突变株,其中突变株12-82在50℃水浴60min以及70℃水浴1.5min的酶活残留率均比出发株高出近20%,且80℃保温2min仍有11.9%的酶活残留率。结论:利用NTG诱变结合96孔板高通量筛选的方法筛选到5株所产MTG热稳定性相对较高的突变株,其中突变株12-82在50℃、70℃和80℃的酶活残留率均有10%~20%的提高。这为高温食品加工领域所需耐高温MTG生产菌株的高效筛选提供了可行性方案。     

诱变选育雄烯二酮高产菌株及其发酵条件研究

以一株降解植物甾醇产生雄烯二酮的分枝杆菌为研究对象,先后利用亚硝基胍(NTG)和N+注入技术对其进行诱变处理。通过考察NTG浓度和N+注入剂量对菌株诱变效果的影响,确定了最佳诱变条件为NTG浓度为0.6 mg/mL,N+注入剂量为60×1011ions/cm2。最终选育出一株高产突变株Mycobacterium sp.N-2,其生产雄烯二酮的能力较出发菌株提高了37.8%,且传至第七代仍基本稳定。进一步研究了初始pH值、接种量和摇床转速等对高产突变菌株发酵能力的影响,确定了最佳发酵条件为初始pH值7.5,接种量12%,摇床转速260 r/min。     

高产谷胱甘肽新菌种的选育及其发酵条件的研究

通过对谷胱甘肽新产生菌——藤黄八叠球菌进行紫外诱变处理,筛选到一株抗乙硫氨酸和氯化锌的抗性菌株,该突变株发酵生产谷胱甘肽的产量比出发菌株提高268．9％。通过对碳源、氮源、温度、初始pH等发酵条件对该菌株生物合成谷胱甘肽的影响研究,表明突变株HY78在发酵温度37℃、初始pH7.0、摇床转速180r／min条件下,摇瓶发酵26h,该高产菌株在发酵液中合成谷胱甘肽的产量可达160．628mg／L。     

三孢布拉氏霉生物合成β-胡萝卜素的研究──Ⅰ.三孢布拉氏霉负菌优良菌株SCB201的选育

采用紫外照射、亚硝基胍（NTG）和离子束综合诱变处理,获得一株三孢布拉氏霉菌负亩优良菌株SCB201。在优化了的培养条件下,它与三孢布拉氏霉菌正菌SCB200接合培养产β－胡萝卜素达到2g／1,较其亲株0．2g／1的水平提高了10倍。     

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.