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酵母菌属间原生质体融合:构建高产麦角固醇的优良品系 总被引:7,自引:2,他引:5
采用属间原生质体融合技术,对麦角固醇含量较高、细胞生物量低的裂殖酵母(Schziosacch-aromyces)单倍体YG-1-14-58(amet-trp-)与细胞生物量较高、麦角固醇含量低的酿酒酵母(Succh-aromyces)单倍体YG-28-32-135(aade-hix-)进行原生质体融合,在高渗基本选择培养基上挑选融合子,并对获得的大量融合子进行了形态、生理生化、遗传稳定性、细 相似文献
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以龟裂链霉菌(S.Rimosus,Otcr,Sm s)和灰色链霉菌(S.Griseus,Smr,Otcs)为原始出发菌株,经NTG诱变处理,获得前者(Asp-)和后者(cys-)营养缺陷型突变株,制成109个/m1等量原生质体混合液,在岛津细胞融合装置SSH—C11融合槽(电极间距为0.5mm)内,以频率lMHz、强度800V/cm的高频交流电场作电介质,电泳15s形成原生质体珠串,旋即施加电场强度6 kV/cm、短时程20μs的直流高压方形电脉冲触发原生质体融合,在R3再生培养基上选取34971个菌落,移植于双抗基本培养基,检出四个双抗原养型融合子。它们具有亲株的优良生物学特性,生长速度较快,产素能力大,抗菌活性高。生物显影结果表明,它还产生两个亲株所不具有的抗菌活性物质。 相似文献
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利用淀粉产生碱性蛋白酶工程菌的构建 总被引:8,自引:0,他引:8
以不能利用淀粉为碳源、抗pp系列噬菌体和pL1噬菌体、产碱性蛋白酶(9400-9800u/ml)的BacilluspumilusC172-60为受体株,采用原生质体转化技术将携带糖化型小淀粉酶基因(Amv)、Cmr基因、Kmr基因的pBX96质粒导入到受体株内,经两次利福平抗性筛选,获得一株能直接利用淀粉为发酵碳源、保留噬菌体抗性、产碱性蛋白酶的工程菌C172-306(pBX96)。菌体增殖96.5代质粒丢失率为0.77%,摇瓶发酵蛋白酶活力140 相似文献
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酵母属间原生质体融合改进菌株木糖发酵性能 总被引:2,自引:0,他引:2
通过单倍体分离和紫外诱变,获得了14株树干毕赤酵母(Pichiastipitis)7124和酿酒酵母(Sacharomycescerevisiae)1300的营养缺陷型突变株。用聚乙二醇(PEG)和电诱导融合及致死融合等方法,实现了树干毕赤酵母和酿酒酵母的属间原生质体融合。融合子能发酵木糖产生酒精,其厌氧发酵木糖和木糖葡萄糖混合液的能力明显优于亲株,耐酒精的性能也比亲株树干毕赤酵母7124有所提高。融合子经DNA含量、细胞体积测定和稳定性能实验证明为稳定融合子。 相似文献
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1.试验确定了Candida utilis的存活率随照射剂量的增加而减小,它与γ-射线(Co60)剂量之间是成指数曲线的关系。其年致死剂量(LD50)为52,200伦。
2.在获得的2,012株营养缺陷菌株中选出了31株稚生素B1的缺陷菌株,共占整个营养缺陷型的1.54%。
3.在细胞大小,菌落直径,氧的吸收以及假菌丝发达程度等方面;缺陷菌株均比原始菌株显出不同程度的差异。在生长曲线方面,缺陷菌株的对数期一般均比原始菌株有所延长。
4.在细胞色素系统方面,在整个维生素B1的缺陷菌株里,仅发现5株是缺细胞色素a的,其余的B1缺陷菌株与原始菌株溲有差别。
5.所获得的B1缺陷菌株经两年多、20—50次左右的转接保存,它们对稚生素B1需要的缺陷特性是稳定的。 相似文献
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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. 相似文献
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RICHARD E. NORRIS 《Botanical journal of the Linnean Society. Linnean Society of London》1991,106(1):1-40
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. 相似文献
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JOAN VALUÈS MONTSERRAT TORRELL NÚRIA GARCIA JACAS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):399-407
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. 相似文献
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肝癌中HBV和HCV基因和抗原的分布及意义 总被引:1,自引:0,他引:1
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 相似文献
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H.-R. GREGORIUS 《Biological journal of the Linnean Society. Linnean Society of London》1984,23(2-3):157-165
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. 相似文献
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. 相似文献