红树内生海洋细菌CIII-1发酵条件初步研究

摇瓶法测定结果表明,用7号培养基,初始pH 7.5,装液量1/10摇瓶体积,转速150 r/min,温度25℃下培养96 h,菌株分泌产生抗番茄青枯病细菌的物质最多,抑菌圈直径最大,为红树植物内生海洋细菌CⅢ-1菌株产抗植物青枯病菌物质的最佳培养条件.并发现该菌株产生的抗菌物质对西瓜枯萎病菌、香蕉枯萎病菌等植物病原真菌也有较强的拮抗作用.     

南极海洋细菌BSw10005生长特性研究

从极地海洋细菌中筛选获得菌株BSw10005,其胞外代谢物质对植物病原真菌有显著的抑制作用。用盐水代替常规的海水米培养极地细菌。在摇瓶中,考察了不同盐浓度、碳源对其生长的影响。利用5L生物反应器,通过改变温度、氧供给条件和控制发酵液pH值,对菌株BSw10005的生长特性作了系统的研究,确定了温度、氧和pH值对菌株生长的影响及菌株培养的最优化的条件。对发酵液中的代谢抑菌活性物质作了初步分离,获得到白色固体粗提物质。     

南极海洋细菌BSw10005生长特性研究*

从极地海洋细菌中筛选获得菌株BSw10005,其胞外代谢物质对植物病原真菌有显著的抑制作用。用盐水代替常规的海水来培养极地细菌。在摇瓶中,考察了不同盐浓度、碳源对其生长的影响。利用5L生物反应器,通过改变温度、氧供给条件和控制发酵液pH值,对菌株BSw10005的生长特性作了系统的研究,确定了温度、氧和pH值对菌株生长的影响及菌株培养的最优化的条件。对发酵液中的代谢抑菌活性物质作了初步分离,获得到白色固体粗提物质。     

拮抗棉花枯萎病菌的地黄内生细菌筛选、鉴定和促生潜能

【目的】为了筛选棉花枯萎病菌拮抗性菌株资源,从药用植物地黄根块中分离内生细菌,分析优良菌株的促植物生长特性和耐盐碱特性,发掘优良菌株资源,为研发棉花枯萎病生防菌剂提供参考价值。【方法】采用平板对峙法对分离内生细菌进行棉花枯萎病菌拮抗性试验,荧光显微镜观察法研究病原菌菌丝的变化、分光光度计法测定吲哚乙酸(IAA)含量和1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性、平板培养法测定溶磷特性、分隔培养法测定产生挥发性物质抑菌性、比浊法测定内生菌的耐盐碱特性、通过测定代表菌株理化特性、16S rDNA序列并分析系统发育地位、盆栽接种试验验证防病效果。【结果】地黄内生细菌对棉花枯萎病菌具有拮抗性,其中菌株DH9、DH66、DH92拮抗作用较强。与对照组菌丝对比,处理组菌丝出现打结、弯曲和断裂现象,菌丝末端分枝明显增多,多数边缘菌丝呈珊瑚状分枝,存在明显被菌体包埋等现象。菌株DH83、DH66、DH92、DH9、DH56产生挥发性物质对棉花枯萎病菌均有抑制作用,但抑制效果不明显。产生IAA含量均大于1.32 mg/L的有7株(DH92、DH30、DH71、DH83、DH93、DH9、DH56),其中DH92产量最高,为34.696mg/L。菌株DH92和DH30产生ACC脱氨酶活力分别为118.612μmol/(mg·h)和103.795μmol/(mg·h)。菌株DH92无机磷溶磷能力最强,溶磷圈直径/菌落直径(D/d)为1.51;菌株DH71溶解有机磷能力最强,D/d为4.50。菌株DH9和DH56分别能够耐受在7%、3%NaCl盐浓度,在pH 8–10均能生长,具有一定耐盐碱性。结合菌株培养特征、生理生化特性和16S rDNA测序及系统发育分析,结果表明DH30最相似菌株为沙福芽孢杆菌(Bacillus safensis),DH9最相似菌株为枯草芽孢杆菌(Bacillussubtilis),DH92最相似菌株为菠萝泛菌(Pantoea ananatis)。DH92处理组防治效果达77.29%,其他防效在63%以上,可作为棉花枯萎病的生防菌株资源。【结论】药用植物地黄根块中存在棉花枯萎病菌拮抗性菌株资源,其中菠萝泛菌DH92从地黄根块中分离未曾见报道。优良地黄内生细菌具有促进植物生长特性和一定耐盐碱性,为防治棉花枯萎病和研发生物防治菌剂提供了基础。     

甲醇利用型吡咯喹啉醌产生菌的筛选及鉴定

从虎杖内生细菌和黏细菌中筛选吡咯喹啉醌(PQQ)产生菌。采用3种以甲醇为唯一碳源的培养基对160株供试菌株进行摇瓶培养发酵,发酵产物采用光谱学分析法及HPLC法筛选。结果显示,通过初筛和复筛共得到甲醇利用型菌134株,PQQ产生菌4株,其中菌株083114的PQQ产量为64.34 mg/L。菌株083114的16S rRNA基因序列分析结果显示,其序列与酸快生芽孢杆菌(Bacillus acidiceler)的系统发育关系最近。虎杖内生细菌及黏细菌中存在PQQ产生菌。     

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。     

苦豆子根瘤内生细菌分离及其对棉花枯萎病的生物防治效果测定

对从塔里木盆地苦豆子中分离得到的内生细菌进行皿内涂布拮抗实验、对峙培养法拮抗实验、胞外分泌物拮抗性测定和盆栽控病实验等研究,结果表明塔里木盆地苦豆子根瘤中存在大量的棉花枯萎病菌拮抗性内生细菌。皿内涂布法筛选结果表明60株苦豆子根瘤内生细菌中有48株相对抑菌率超过50%。对峙培养法对48株拮抗性内生细菌进一步筛选的结果表明,对棉花枯萎病菌抑菌距离超过20 mm的菌株有40株。40株拮抗性内生细菌胞外分泌物对棉花枯萎病菌的抑菌距离超过5 mm的有26株。KDRE12和KDRE41对棉花枯萎病的盆栽控病平均防效分别为67.11%和72.65%,具有应用潜力。     

Cp-S316菌株抗细菌活性物质对大肠杆菌的抑制作用及高产突变株选育

通过测定大肠杆菌K12 (Escherichia coli K12)菌悬液的OD260的变化, 研究了多粘类芽孢杆菌(Paenibacillus polymyxa)Cp-S316抗细菌活性物质对其细胞膜完整性的影响, 结果表明Cp-S316抗细菌活性物质可损伤大肠杆菌K12的细胞膜, 从而引起胞内RNA、DNA等大分子物质的泄漏。为获得抗细菌活性物质高产菌株, 以Cp-S316为出发菌株, 通过紫外诱变以及对自身产生的抗细菌活性物质的抗性筛选法进行预筛、摇瓶初筛和复筛, 获得突变株多粘类芽孢杆菌A17, 其发酵效价比出发菌株Cp-S316提高91%, 该突变株的高产遗传性状稳定。     

一株拮抗番茄叶霉病菌的放线菌筛选、鉴定及发酵条件研究

菌株xjy是一株从新疆棉田土壤中筛选出的对番茄叶霉病菌(Fulviafulva)有较强拮抗作用的放线菌,其对23种常见植物病原真菌和6种细菌有较好的抑制效果,抗菌谱广。其形态特征、培养特性、生理生化特性、细胞壁组分与放线菌中的淡紫灰链霉菌(Streptomyces lavendulae)相同,16SrDNA序列同源性达99.6%。研究发现该菌的摇瓶发酵配方和培养条件为:大豆粉2%、葡萄糖2%、NaCl0.8%、CaCO30.2%、(NH4)2SO40.32%,起始pH7.0、28℃、180r/mim、摇瓶培养6d,这些结果为该菌株今后的应用、抗生素的分离提纯和产业化提供了实验依据。     

淡色生赤壳菌(Bionectria ochroleuca)Bo-1菌株产生抗菌物质的发酵条件优化

以淡色生赤壳菌(Bionectria ochroleuca)Bo-1菌株发酵液乙酸乙酯粗提物对水稻白叶枯病菌(Xanthomonas oryzaepv.oryzae,Xoo)抑菌活性为检测指标,采用单因素试验优化Bo-1菌株产生抗菌物质培养所需的碳源、氮源、无机盐;通过正交试验优化培养基配方和摇瓶发酵条件。研究结果表明,Bo-1菌株产生抗菌物质适宜的碳源、氮源和无机盐分别为淀粉、蛋白胨、MgSO4·7H2O;优化的培养基配方为:淀粉30 g/L,蛋白胨2 g/L,MgSO4·7H2O 0.5 g/L;适宜的发酵条件为:温度30℃,转速150 r/min,装液量80 mL/250 mL,pH 6.5。     

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.     

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     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various