地衣芽孢杆菌TS-01固态发酵培养基的优化*

分离到一株饲用地衣芽孢杆菌TS-01 ,初步研究了该菌的固态发酵培养基 ,得到的最优发酵培养基为 (g/kg干固体物料 )含水量 60 0、红糖 7、米糠 42 0、麸皮 5 80。当采用此种配比的培养基 ,接种量为 10%(v/w) ,发酵 2d后 ,菌体浓度可达 9.15×10⁹CFU/g鲜曲 ,芽孢浓度可达 7.50×10⁹CFU/g鲜曲 ,芽孢形成率在 80 %以上。     

初始接种量对Bt33菌株孢子含量的影响

在温度 30± 0 5℃、转速 180r/min的条件下 ,用Bt发酵培养液对Bt33菌株进行振荡培养 ,考察不同接种量和液培时间对孢子含量的影响。结果表明 ,将孢子含量为 2 5× 10 9CFU ml的母液按 1%～ 15 % (V V)的比例接种后培养 33～ 5 0h ,9%和 12 %接种量处理能产生 8 5× 10 9CFU ml以上的孢子浓度。通过拟合逻辑斯蒂生长模型 ,发现该菌在上述液培条件下的最大孢子含量为 1 0 3× 10 1 0 CFU ml。     

地衣芽孢杆菌TS-01固态发酵培养基的优化

分离到一株饲用地衣芽孢杆菌TS-01,初步研究了该菌的固态发酵培养基,得到的最优发酵培养基为(g/kg干固体物料)含水量600、红糖7、米糠420、麸皮580.当采用此种配比的培养基,接种量为10%(v/w),发酵2 d后,菌体浓度可达9.15×109CFU/g鲜曲,芽孢浓度可达7.50×109CFU/g鲜曲,芽孢形成率在80%以上.     

α-葡萄糖苷酶菌株的选育及发酵条件的研究

从2株芽胞杆菌中通过筛选获得了一株产α-葡萄糖苷酶活力较高的嗜热脂肪芽孢杆菌U2,以嗜热芽孢杆菌U2为菌种,优化发酵培养基后,在温度45℃、初始pH6.8、转速200r/min和10%接种量条件下,发酵20h,菌株U2产酶水平可达到2.62U/mL,比出发菌提高了4倍。     

棉花根际亲和性高效促生细菌的分离筛选

为了从棉花根际土壤筛选能与棉花凝集素具有亲和作用的高效促生细菌,以选择性培养基从棉花根部初步筛选具有固氮能力、解磷能力及解钾能力的促生细菌,再以异硫氰酸磺(FITC)标记的棉花凝集素为复筛工具,从棉花根际促生细菌中筛选能与棉花凝集素结合的亲和性菌株,分别挑选2株固氮菌、2株解磷细菌和2株解钾细菌作为微生物肥料接种到棉花根部进行盆栽试验.观察其在根部定殖情况.结果是在选择性平板上有20%～30%的菌株具有凝集素染色阳性.盆栽试验显示,接种的6株亲和性菌株能在棉花根部成功定殖,根际细菌数量约是灭活对照的`0倍.通过初步鉴定,固氮菌株N1111为固氮菌属(Azotobacter),N2121属于德克斯氏菌属(Derxia);解磷菌株P2126属于黄单胞菌属(Xanthomonas),P1108菌株为假单胞菌属(Pseudomonas);解钾菌株K2204和K2116属于芽孢杆菌属(Bacillus).     

一株病原拮抗野生菌株的筛选、鉴定及其发酵工艺优化

为获得广谱抗菌功能野生菌株并提高其发酵产物中抗菌物质的含量。采用管碟法和菌丝生长速率法筛选功能菌株,ITS序列分析鉴定功能菌株,通过响应面法和正交设计优化发酵生产抗菌物质的工艺。筛选到一株强效、广谱抗菌功能菌株,鉴定为Cerrena sp.,其发酵产物对金黄色葡萄球菌、大肠杆菌、白色念珠菌、枯草芽孢杆菌和水稻纹枯病菌有显著拮抗作用。该菌株的摇甁发酵配方及培养条件为：马铃薯13.99 g/L,蔗糖 41.58 g/L,VB1 0.027 g/L,麸皮7 g/L,KH₂PO₄ 2 g/L,MgSO₄·7H₂O 2 g/L;摇床温度28 ℃、发酵周期10 d、种龄4 d、接种量8%、初始pH为5.0、装液量110 ml/250 ml。该菌株有明显抑菌活性,发酵工艺优化后抗菌活性提高了30.37%,为该菌株今后的应用、抗菌剂的分离提纯和产业化提供了实验依据。     

耐盐性毒死蜱降解菌HY-1 的产酶培养基及发酵条件优化

为了明确生化处理和微生物降解的关系,通过增加耐盐菌的比例可以提高农药废水生化处理效果。从农药厂废水中分离到1株耐盐性毒死蜱降解菌——蜡状芽孢杆菌(Bacillus cereus HY-1),以从该菌中提取到的降解酶比活力为指标,进行产酶培养基和发酵条件的优化研究。通过单一因素试验和正交试验,对细菌HY-1的产酸培养基和发酵条件进行了优化。运用SPSS软件进行结果分析,所获优化培养基配方为:葡萄糖6.0 g/L,胰蛋白胨2.2 g/L,K2HPO4 2.0 g/L,KH2PO4 0.2 g/L,MgSO4.7H2O 0.1 g/L,NaCl 0.1 g/L和微量元素溶液2 mL/L。得到菌株发酵培养的最佳优化条件为:种子液培养时间为16 h,发酵培养时间为18 h,接种量为1%(V/V),发酵培养基初始pH值为7.0。氯化钠浓度为0?30 g/L时降解酶比活力不受影响,这是已报道的耐盐性最强的一株毒死蜱降解菌。     

一株芽孢杆菌在维生素C二步发酵中对小菌的促进作用

从土壤中分离到1株能更好促使小菌生长和产酸的芽孢杆菌B601,作为伴生菌与巨大芽孢杆菌相比,在生长过程中,发酵液中B601活菌数小于巨大芽孢杆菌,而其芽孢数则多于巨大芽孢杆菌。对B601组成菌系的发酵条件进行优化,得到如下结果：100g／L L-山梨糖、6g／L尿素、10g/L玉米浆、培养温度30℃和发酵周期44h。与巨大芽孢杆菌组成菌系相比其底物,L-山梨糖质量浓度提高了25％,尿素下降了50％．玉米浆质量浓度下降了33％,温度提高了2℃,发酵周期缩短了4h。结果表明：B601作为伴生菌,与巨大芽孢杆菌相比,该菌株明显提高了发酵效率。     

降解菜籽饼粗蛋白耐盐菌的筛选、鉴定及固体发酵的初步研究

从保存6个月含菜籽饼的堆肥样品中筛选到3株耐盐菌株A2、A4、A7,这些菌株能以菜籽饼为氮源生长,最高耐盐浓度达到10%,经分子生物学及系统发育分析,A2、A4为解淀粉芽孢杆菌,A7为栗褐芽孢杆菌,通过单一菌株固体发酵菜籽饼试验,这些细菌均对菜籽饼表现出了一定的降解能力。     

产氨短杆菌与枯草杆菌发酵产肌苷比较试验

采用诱变得来的枯草杆菌GMI-741和产氨短杆菌GMA-2892在1.2L自控发酵罐上进行肌苷发酵试验,产氨短杆菌GMA-2802在种子培养基中培养15h后,菌浓度达1.0×1011个/ml,而同样条件下,枯草杆菌GMI-741菌浓度只有9.5×109个/ml.在1.2L自控发酵罐上发酵时,GMA-2802发酵周期54h,产肌苷达20.40g/L,发酵液主要原材料成本为441.1元/吨;GMI-741发酵周期60h,产肌苷达19.52g/L,发酵液主要原材料成本为559.1元/吨.     

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.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

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