金属离子对酵母胞内核黄素产量的影响

研究了金属离子对脆壁酵母 (Saccharomycesefragilis)RY 5胞内核黄素积累的影响 ,运用均匀设计方法进行了培养基优化。结果表明 :Mg2 + ,Zn2 + ,Fe2 + 对RY 5的核黄素产量有着显著影响 ,培养基中金属离子的最佳浓度为 :MgSO4·7H2 O 1 .1g/L ;CoSO4·7H2 O 2 8mg/L ;CuSO4·5H2 O 0 .0 1mg/L ;MnCl2 0 .0 2mg/L ;ZnSO4·7H2 O 3 4mg/L ;FeSO4·7H2 O 1 4mg/L ,RY 5的核黄素产量可达 1 40mg/kg。     

烟叶果胶质分解菌的选育

从烟叶叶面分离到产果胶酶真菌 18株 ,在此基础上 ,进行液体培养 ,测定酶活 ,得到一株酶活性较高的黄曲霉DPE - 0 0 5。对该菌株产酶培养基的碳、氮源进行正交法研究 ,正交实验的结果表明 ,影响该菌产酶活性的因素依次为A(麸皮 ) >B(乳糖 ) >C(果胶 ) >D(硫酸铵 ) ,其最佳组合为A2B3C3D1。最适产酶条件为 :麸皮 4 0 % ,果胶 0 3% ,乳糖 1 5 % ,(NH4 ) 2 SO4 0 5 % ,KH2 PO4 0 2 5 % ,MgSO4 ·7H2 O 0 0 5 % ,NaNO30 0 2 % ,FeSO4 ·7H2 O 0 0 0 1% ,起始pH 6 0 ,在 2 8℃摇床培养 7d产酶量达到最高。以玉溪B3F烟叶为材料 ,施加DPE - 0 0 5菌株所产酶液 ,在 5 0℃贮存 12h。经化学成分检测 ,结果表明 ,果胶质降低了 18 15 %。     

根瘤菌4012a菌株产细胞分裂素发酵条件的研究

用酶标免疫检测法研究了根瘤菌4012a菌株细胞分裂素发酵的适宜培养基和培养条件。结果表明,其最佳培养基为（g／L）：葡萄糖10.0,（NH4）2SO41.0,K2HPO4·3H2O0．6,MgSO4·7H2O0.1,CaCl2·2H2O0.4,FeCI3·6H2O0．04,Na2MoO4·2H2O0．1mg／L,泛酸钙100μg／L,腺漂吟200mg／L。该菌株在150r／min的旋转摇床上27℃振荡培养96h,发酵液中细胞分裂素产量可达908μg／L,生物活性（萝卜子叶扩大法）为1mg／L激动素当量。     

假丝酵母YQ5产S-腺苷甲硫氨酸的发酵培养基优化

利用单因子实验和正交实验对假丝酵母(Candida sp.)突变菌株YQ5摇瓶发酵产生S-腺苷甲硫氨酸的培养基成分进行了优化。单因子实验结果表明, 发酵最适pH值为6.0, 最佳碳源为 8%蔗糖, 最佳氮源为1.5%胰蛋白胨, 酵母粉最适浓度为2%, MgSO4·7H2O、CaCl2、FeSO4·7H2O、CoCl2、CuSO4·5H2O、H3BO3等作为无机离子对胞内S-腺苷甲硫氨酸的积累均有促进作用。利 用正交实验获得了最终的发酵培养基配方。在最适条件下发酵48 h, S-腺苷甲硫氨酸含量可达1740.0 mg/L。     

链霉菌发酵麦草产木聚糖酶的试验研究

通过正交设计试验 ,找出利用链霉菌和麦草基质发酵生产木聚糖酶的试验条件。培养基 (g/L) :麦草粉 ,4 5 ;(NH4 ) 2 SO4 ,7.5 ;酵母膏 ,8;K2 HPO4 ·3H2 O ,1;MgSO4 ·7H2 O ,0 .5 ;NaCl,0 .3。接种量为 5 .0× 10 8个孢子 / 5 0mL培养基 ,振荡培养 (12 0r/min) 5d     

枯草芽孢杆菌B47菌株高产抗菌物质的培养基及发酵条件优化

枯草芽孢杆菌Bacillus subtilis B47菌株为番茄内生细菌, 也是玉米小斑病拮抗菌, 能产生对玉米小斑病菌有强烈抑制作用的抗菌物质。以B47菌株发酵液的无菌滤液对玉米小斑病菌的抗菌活性为检测指标, 测定B47菌株产抗菌物质培养所需的最佳碳、氮源和无机盐, 并通过正交试验法对该菌株产抗菌物质的培养基配方和摇瓶发酵条件进行优化。研究结果表明, B47菌株产抗菌物质最佳碳、氮源和无机盐分别为蔗糖、酵母浸膏和MgSO4·7H2O, 最优培养基是YSB (Yeast extract-sucrose-beef extract)培养基, 其配方为: 蔗糖2%, 酵母浸膏2%, 牛肉浸膏1.5%, MgSO4?7H2O 0.06%, FeSO4·7H2O 0.000 9%, 最优发酵条件组合为: 30 °C, pH 7.0, 170 r/min摇床培养6 d, 接种量为1%, 装液量为40 mL/200 mL。     

高产纤维素酶热纤梭菌选育及酶活力最适表达条件研究

1材料与方法1.1材料热纤梭菌:法国Institut Pasteur赠送;稻草粉的制备:取无霉变的新稻草粉碎,过标准筛;酶活力基础培养基(质量分数,%):稻草粉、麦麸、MgSO40.05,K2HPO40.4,KH2PO40.4,MgCl2·6H2O0.05,(NH4)2SO40.5,CaCl2·2H2O0.01,FeSO4·7H2O0.01;纤维素平板培养基:CMC培养基;斜面诱导培养基:稻草粉加适量无机盐组成;培养条件:50℃厌氧缸(N2∶CO2∶H2为90∶5∶5)培养3~4d。1.2方法菌株复壮和UV诱变:将菌株接种在平板培养基上培养,挑选生长好的菌落,在斜面诱导培养基上连续传代数次,接种液体酶活力基础培养基,测定酶活力。…     

壳聚糖酶生产菌的筛选、鉴定及其产酶培养条件的研究

从土样中分离到60株分泌胞外壳聚糖酶的菌株,经过筛选,其中有1株细菌产酶能力较高.生理生化试验鉴定该细菌为假单胞菌(Pseudomonas sp.).对假单胞菌产酶的培养条件研究结果表明:最适培养基组分为(g/L):壳聚糖5,氨基葡萄糖2,硝酸氨2,MgSO4·7H2O 0.5,KH2PO4 0.4,KCL 0.5,FeSO4·7H2O 0.01,起始pH 6.5;适宜培养条件是:接种量2.0×107个/50ml培养液,28℃,120 r/min振荡培养3d.     

球衣菌合成聚羟基烷酸(PHA)的发酵研究

研究了球衣菌 (Sphaerotilussp.)W991 3 6合成聚羟基烷酸 (PHA)的培养基配方及发酵条件。结果表明 ,W991 3 6适宜发酵培养基配方为 :葡萄糖 1 0 2 5g/L ,蛋白胨 2 6 3g/L ,MgSO4·7H2 O 0 1 7g/L ,CaCl2 0 0 5g/L ,NaH2 PO4·2H2 O 0 0 2g/L ,K2 HPO40 0 4g/L ,KH2 PO40 0 3g/L ;最佳接种量为 0 1 3 8g (干 ) / 1 0 0mL ,培养基适宜初     

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。     

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.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

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     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

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.     

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.