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芽孢杆菌M_(50)产生β甘露聚糖酶的条件研究 总被引:3,自引:0,他引:3
从土壤中分离到9 株产生β甘露聚糖酶的芽孢杆菌( Bacillus sp .) 。Bacillussp . M50250m L三角瓶摇瓶培养试验,以4 % 的魔芋粉为碳源,1-0 % ( NH4)2SO4 为氮源,0-35 %Na2CO3 ,30 ~34 ℃培养60h 产酶达到高峰。酶活力为180 ~200u/m L。100L 罐发酵,在30 ~32 ℃,1∶0 .75vvm 通气量,200r/min 条件下,发酵液酶活力高达330u/m L。酶的最适反应温度和pH 分别为50 ℃和6-0 ,低于50 ℃,pH5 .0 ~7 .0 酶稳定。Fe3+ 、Al3+ 、EDTA、Hg2+ 对酶有抑制作用,而Ba2+ 、Mn2+ 对酶有激活作用。发酵粗酶液对苎麻精干麻精练,显示对精干麻的半纤维素残胶具有降解作用。 相似文献
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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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产β1 ,4D甘露聚糖酶的诺卡氏菌形放线菌( Nocardioform actinomycetes) 菌株NA3540 ,发酵培养72h ,发酵液离心去菌体,上清经硫酸铵沉淀,95 % 乙醇沉淀,CMSephadex A50 柱层析、羟基磷灰石柱层析、DEAE纤维素离子交换及Sephadex G100 分子凝胶过滤柱等步骤,β甘露聚糖酶的比活提高了137 倍,获得凝胶电泳均一的蛋白样品。经SDSPAGE 和凝胶过滤法分别测定β甘露聚糖酶分子量为41kD和40kD,证明该酶为单聚体;用等电聚焦电泳测得其等电点为4-8 ;经氨基酸组成分析,发现蛋白中有较高含量的Gly、Asp、Ala 及Glu 残基。该酶的最适反应温度为75 ℃,在不超过60 ℃时酶活较稳定;酶反应的最适pH 为8-0 ,pH 稳定范围为6-5~11-0 。重金属离子Hg2+ 、Cu2+ 、Pb2+ 、Fe3+ 、Co2+ 、Zn2+ 能强烈抑制该酶活性,而Mn2+ 、Fe2+ 、Ag+ 对该酶有部分的抑制作用,低浓度的Na+ 、K+ 、Li+ 对该酶基本没有影响。 相似文献
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无花果曲霉原生质体形成与再生条件的探讨 总被引:7,自引:1,他引:6
根据正交试验得出无花果曲霉原生质体形成的最佳条件,用1%的混合酶液(0.5%纤维素酶+0.25%蜗牛酶+0.25%溶菌酶)作用无花果曲霉菌体细胞,原生质体产量达3.2×107个·ml-1,渗透压稳定剂为0.6mol·L-1KCl于0.2mol·L-1PO3+4(pH5.8)中,酶解时间和酶解温度分别为3.0h、30℃.比较不同酶解时间、再生稳定剂和碳源等因素对原生质体再生的影响,可确定最佳再生条件,再生率达30%以上. 相似文献
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米曲霉原生质体融合及杂合二倍体的形成 总被引:19,自引:1,他引:18
采用混合酶液处理纤维素酶高产苗株3042N-2(天冬酰胺缺陷型“Asn-”)及蛋白酶高产菌株3042N-19(蛋氨酸缺陷型“Met-”)的营养菌丝,获得原生质体,以PEG为助融剂进行融合处理,成功地获得了米曲霉(Aspergillusoryzae)原生质体的营养互补融合。将异核体菌落的菌丝转接到合有0.1%樟脑的新鲜MM上,25℃诱导培养7─15天,挑取绿色角变菌落的孢子,将其转接到MM上能迅速生长,经孢 相似文献
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蔗渣水解液发酵乙醇的研究 总被引:14,自引:0,他引:14
研究了酵母(Pichiastipitis)Y7124在限制供氧条件下尽管反应初期葡萄糖消耗速率大于木糖,但在一定时间后,葡萄糖的消耗速率变慢,而木糖消耗速率变快直至耗尽的现象。建立了气升柱以P.Stipitis转化木糖为目的和以溢流柱Sacharomycescerivisiae转化残留葡萄糖为目的的串联发酵乙醇工艺,即流加5倍浓缩的蔗渣水解液,D=0.1h-1,还原糖总利用率为97.2%,酒精浓度为46.5g/L,生产率为4.1g/L·h。 相似文献
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克鲁维酵母种间原生质体融合的研究 总被引:5,自引:0,他引:5
乳酸克鲁维酵母(Kluyueromyces lactis Y12—1)和脆壁克鲁维酵母(K.fragilis8554)是乳糖酶生产菌株。应用原生质体融合技术进行了两菌株种问融合的研究。通过试验.原生质体形成及再生的最佳条件为:对数期的细胞,2%的蜗牛酶.30℃酶解30分钟.原生质体形成率90%以上,再生率20%左右。原生质体融合由聚乙二醇(PEG)诱导。K.lactisY12-l不能旋酵菊糖;K.fragilis 8554不能同化D-松三糖和麦芽糖;利用二菌株自身的营养缺陷性质获得融合子。融合子既能发酵菊糖又能同化D-松三糖和麦芽糖;融合子的DNA含量约为二亲株之和;融合子的菌落形态与亲株相比有一定差别.在以乳糖为碳源的培养基中,融合子的乳糖酶产量提高14一l6%;连续15次传代,融合子稳定。 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