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通过链霉素对南昌霉素 (Nanchangmycin)产生菌NS 41 80菌株孢子的致死浓度测定基础上 ,采用诱变剂甲基磺酸乙酯 (EMS)的不同诱变剂量对菌株孢子进行诱变处理 ,诱变处理的孢子涂布在含链霉素 ( 1 0 μg/mL)致死浓度的高氏平板上 ,获得了大量的链霉素抗性基因 (str)突变株。然后从 3,0 0 0株链霉素抗性基因 (str)突变株中通过初筛获得比诱变出发菌株产素能力提高 2 0 %以上的菌株 2 0 2株。再进一步通过摇瓶复筛 ,获得比出发菌株产素能力分别提高 1 相似文献
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梅岭霉素高产菌株链霉素抗性基因突变株筛选 总被引:8,自引:0,他引:8
通过链霉素对梅岭霉素 (Meilingmycin)产生菌南昌链霉菌NS 41 80菌株孢子致死浓度的测定 ,采用诱变剂EMS 4种不同剂量对菌株孢子进行诱变处理 ,然后涂布在含链霉素致死浓度的高氏平板上 ,获得了大量的链霉素抗性基因 (str)突变株。并进一步筛选到梅岭霉素高产菌株 80 5 1 1 2 2 1 ,在摇瓶条件下 ,只产梅岭霉素不产南昌霉素 ,梅岭霉素活性单位达 1 ,52 1 μg/mL,比NS 41 80的摇瓶发酵单位 855μg/mL提高了 77 9% ,该菌株连续传 6代进行摇瓶发酵 相似文献
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采用微波结合链霉素抗性筛选法选育放线菌素D的高产菌株。通过考察链霉素对Streptomyces rubiginosohelvolus FIM-N31菌株孢子生长情况的影响确定链霉素致死浓度,出发菌株FIM-N31的孢子经微波辐照处理后,涂布在含链霉素致死浓度(50 μg/mL)的培养基平板上培养,获得了大量的链霉素抗性基因突变株。摇瓶发酵筛选突变株,结果获得一株遗传性状稳定的放线菌素D高产菌Str186,其产放线菌素D的能力比出发菌株提高了8倍以上。 相似文献
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通过获得链霉素抗性基因突变株筛选小诺霉素高产菌株 总被引:1,自引:1,他引:0
通过链霉素对小诺霉素产生菌 (Micromonospora purpura) 49 1 2 #菌株孢子致死浓度的测定 ,采用诱变剂EMS 3种不同诱变剂量对菌株的孢子进行诱变处理 ,诱变处理的孢子涂布在含链霉素致死浓度的改良高氏平板上 ,获得大量的链霉素抗性基因突变株 ,然后从链霉素抗性基因突变株进一步筛选小诺霉素高产菌株 ,获得小诺霉素菌株 49 1 2 3菌株。在摇瓶条件下 ,其产小诺霉素生物活性单位比出发菌株 49 1 2 #的摇瓶发酵单位提高了 40 %以上。小诺霉素的组分比由出发菌株的C2b∶C1a的 5∶5提高到 8∶2。C2b有效组分提高了 30 %;链霉素抗性基因突变与小诺霉素发酵单位突变之间 ,小诺霉素正突变率达到 40 %,负突变率达 2 6%,正突变大于负突变 相似文献
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梅岭霉素产生菌抗药性突变标志诱变筛选模型的初步研究 总被引:3,自引:0,他引:3
本文通过梅岭霉素 (Meilingmycin)产生菌南昌链霉菌NS 4 1 80菌株孢子对 6种抗生素敏感性测定 ,采用诱变剂EMS四种不同诱变剂量对菌株孢子进行诱变处理 ,诱变处理的孢子涂布在含致死浓度链霉素的高氏平板上。然后从抗药性突变标志菌株中进一步筛选梅岭霉素高产菌株。在 150 0多个抗药性突变株中通过初筛获得了比诱变出发菌株的产素能力提高 50 %以上菌株。通过诱变剂量分别与抗药性突变率和突变株产素产量的变势统计分析表明 ,菌株抗药性突变与产素突变密切相关 ,产素突变的EMS诱变剂量高于抗药性突变诱变剂量 ,在 0 .0 3mol/LEMS剂量作用下 ,菌株致死率为 99.4 3% ,抗药性突变率为 0 .0 4 4 0 % ,建立了梅岭霉素产生菌抗药性突变标志诱变推理性筛选模型。为南昌链霉菌高产菌种选育研究作了有益的尝试 ,并有助于其它链霉菌属的抗生素产生菌育种研究。 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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正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases 相似文献
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Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme
responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare
the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show
that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by
distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of
demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least
one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of
the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable
potent antiproliferative synthetic drugs. 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