盐度和pH对红树根际土壤来源的曲霉属真菌F3的生长及分泌活性物质的影响

本研究考察了一株从中国海南东寨港红树林保护区的红海榄根际土壤中分离得到的曲霉属真茵F3在不同盐度和pH的SDA培养基中的生长和分泌抗茵活性代谢产物的变化.结果显示:高盐环境(3%～9%)及偏碱性条件(pH 8～10)有利于该真菌的生长.在初步优化培养基及培养条件的基础上,通过发酵和有机溶剂萃取的方法获得了该真菌发酵液的乙酸乙酯浸膏,得率为448 mg/L.该浸膏对多种微生物的生长具有明显的抑制作用,其中对细菌Staphylococcusaureus、S.epidermidis,Sarcina lutea、Bacillus subtilis和Escherichia coli的MIC分别为31.3μg/mL、31.3μg/mL、7.8μg/mL、7.8μg/mL和125.0μg/mL;对真菌Candida albicans的MIC为125.0μg/mL.研究同时表明:该乙酸乙酯浸膏还具有明显的细胞毒活性,其对人脐静脉内皮细胞ECV304、人结肠癌细胞Lovo以及肝癌细胞HepG2的IC50分别为3.45μg/mL、4.88μg/mL和14.31 μg/mL.     

木榄内生真菌菌株ZD6及其代谢产物的抑菌活性

根据形态学特征和ITS序列分析结果,将一株从木榄茎中分离到的内生真菌菌株ZD6鉴定为桔青霉Penicillium citrinum Thom.,该菌株在优化后的发酵培养基(1%麦芽糖,2%甘露醇,1%谷氨酸钠,0.5%蛋白胨,0.15%酵母膏,200g/L土豆汁,pH6.5)中28℃、160r/min振荡培养7d后的发酵液具有明显的抑菌活性。利用柱层析及重结晶等方法从该发酵液的乙酸乙酯和正丁醇提取物中分离得到4个化合物:大黄素、环(丙氨酸-甘氨酸)、赤藓醇和甘露醇,其中的大黄素和赤藓醇为首次在桔青霉中发现,它们对枯草芽孢杆菌Bacillus subtilis的生长具有明显的抑制作用,最低抑菌浓度(MIC)分别为25μg/mL和50μg/mL;大黄素对绿脓杆菌Pseudomonas aeruginosa的生长也具有一定的抑制作用,MIC为100μg/mL。     

来自红海榄根际土壤的曲霉属真菌F7菌株及其生物活性分析

基于菌落和菌体的形态特征以及ITS序列分析结果,将分离自中国海南省海口市东寨港红树林保护区红海榄根际土壤的菌株F7鉴定为曲霉属黄绿组的一种真菌。在确定和优化菌株F7培养基的基础上,初步确定了适合其分泌活性代谢产物的改良查氏培养基组成:3%乳糖,1%蛋白胨,0.3%NaNO3,0.05%KCl,0.05%MgSO4·7H2O,0.001%FeSO4,0.1%K2HPO4,pH7.0。将菌株F7接种于该培养基中,28℃下160r/min振荡培养7d后收获发酵液,经乙酸乙酯和正丁醇萃取后获得了乙酸乙酯萃取物(EAE)、正丁醇萃取物(BE)以及水萃取物(WSE),其中EAE和BE对金黄色葡萄球菌、藤黄八叠球菌和枯草芽孢杆菌的生长显示出明显的抑制活性,最低抑菌浓度(MIC)介于0.625-5.0mg/mL之间。同时,上述3种萃取物对人肝癌细胞株HepG2的增殖也表现出一定的抑制活性,IC50约为120μg/mL左右。     

核桃内生真菌抗氧化菌株的筛选及其代谢产物活性研究

本试验以29株核桃内生真菌为研究对象,采用总还原力(FRAP法)及DPPH·清除试验评价其代谢产物的抗氧化能力,从中筛选出高活性菌株,并对该菌株发酵液进行浓缩萃取,研究各萃取物的抗氧化活性。结果表明,供试29株菌的代谢产物都表现出一定的抗氧化活性,其中菌株LTS-6-6(Pyrenochaeta)为高活性菌株。该菌株发酵液乙酸乙酯萃取物(EAE)显示了较强的抗氧化活性,对DPPH·的EC_(50)为7μg/mL,总还原力为527.59±10.66 mg V_C/g,总酚和总黄酮含量分别达到641.14±7.50 mg没食子酸/g、100.30±8.44 mg芦丁/g。该结果表明,核桃内生真菌代谢产物具有一定的抗氧化活性,是寻找天然抗氧化活性物质的良好资源。     

垃圾堆积点土壤中广谱拮抗菌株的分离鉴定及抑菌特性

[目的]从积年垃圾堆积点土壤中筛选具有高效抑菌能力的广谱拮抗菌株并研究其抑菌特性,寻找乡镇垃圾堆积点污染治理的新思路。[方法]采用平板稀释法和管碟法从乡镇积年垃圾堆积点的土壤中分离拮抗真菌,并通过形态观察、生理生化特性及分子生物学鉴定分析对拮抗菌株进行鉴定。通过测定抑菌活性物质的极性,选择合适的有机试剂对拮抗真菌的发酵菌体甲醇浸提物及发酵液进行萃取,并利用TLC-Bioautography法对发酵液及发酵菌体中的抑菌活性组分进行分析。使用23种指示菌测定拮抗真菌DAZ-2的发酵菌体乙酸乙酯粗提物的抑菌广谱,测定粗提物在高温、酸碱、紫外和自然光条件下抑菌能力,以及对大肠杆菌和白色念珠球菌的最小抑菌浓度。[结果]分离得到一株传代稳定的广谱拮抗真菌DAZ-2,经过形态观察、生理生化特性测定及ITS序列分析,菌株鉴定为Aspergillus fumigatus。通过极性测定,选择乙酸乙酯对烟曲霉DAZ-2发酵菌体甲醇浸提物及发酵液进行萃取,TLC-Bioautography法分析表明两者中的抑菌活性物质不是同一组分,且存在多组分物质共同作用产生抑菌效果的可能性;菌体浸提物乙酸乙酯萃取部分(200μg/mL)对11种指示菌具有抑菌效果,对大肠杆菌和白色念珠球菌的MIC为7.50μg/mL和15μg/mL,且对高温、酸碱、紫外、自然光照都具有较强的稳定性。[结论]分离得到一株高效抑菌且传代稳定的广谱拮抗菌株烟曲霉DAZ-2,有希望为微生物药物的开发和乡镇垃圾堆积点污染治理提供科学依据。     

吸水链霉菌BS-112产生的抗真菌活性物质的分离纯化与结构鉴别

【目的】分离纯化吸水链霉菌(Streptomyces hygroscopicus)BS-112产生的抗真菌活性物质,究明各活性组分的结构,测定其对黄曲霉的抑制作用,为该菌株及其产生的抗真菌活性物质的应用提供依据。【方法】通过大孔吸附树脂柱层析、硅胶柱层析及制备HPLC等方法,对该菌株产生的抗真菌活性物质进行分离纯化;利用质谱(MS)和核磁共振谱(NMR)解析各活性组分的结构;采用微量液体稀释法测定各活性组分对黄曲霉的最小抑菌浓度(MIC)和最小杀菌浓度(MFC)。【结果】从BS-112菌株发酵液中分离获得4个抗真菌活性组分,利用波谱技术确定其结构分别为Tetrins A和B、Tetramycins A和B。96孔板法测得这4个化合物对黄曲霉的MIC分别为3.13μg/mL、12.56μg/mL、1.56μg/mL、6.25μg/mL,MFC分别为6.25μg/mL、25.0μg/mL、3.13μg/mL、12.56μg/mL。【结论】BS-112菌株产生的抗真菌活性物质由Tetrins A和B、Ttramycins A和B 4个化合物组成,它们对黄曲霉均具有良好的抑制作用。     

特比萘芬对24株黑酵母样真菌的体外药敏试验研究

目的 评价特比萘芬对7个属24株刺盾霉目（Chaetothyriales）黑酵母样真菌体外敏感性.方法 应用美国国家临床和实验室标准研究所（CLSI）的M38-A2方案.菌悬液终浓度为（0.4 ～5）＆#215;104 CFU/mL,30℃孵育5～7d,测定最低有效浓度（MEC）和最低抑菌浓度（MIC）.结果 特比萘芬对24株黑酵母样真菌MEC范围：0.125 ～4μg/mL,MEC90∶2μg/mL,MEC50∶0.25 μg/mL,GM∶0.392 9 μg/mL,特比萘芬对5株暗色真菌100％生长抑制,MIC范围：1～4 μg/mL,MIC50∶2μg/mL,MIC90∶4μg/mL.结论 特比萘芬对刺盾霉目（Chaetothyriales）中的黑酵母样真菌有较强的抑制作用,50％抑菌作用明显.     

土壤链霉菌KIB-K1次级代谢产物中大环内酯及其抗菌活性研究

为研究土壤链霉菌Streptomyces sp.KIB-K1次级代谢产物成分。实验采用硅胶、凝胶及半制备高效液相等分离方法,从该菌株发酵液中共分离得到7个大环内酯类化合物,通过解析NMR、MS等波谱数据,化合物的结构鉴定为aldgamycin P(1)、aldgamycin E(2)、aldgamycin J(3)、aldgamycin K(4)、aldgamycin L(5)、GERI-155(6)和chalcomycin (7),其中化合物1为新化合物。抗菌实验结果显示,化合物1～7对金黄色葡萄球菌和枯草芽孢杆菌有显著的抑制作用。其中,化合物1对金黄色葡萄球菌的最小抑菌浓度(MIC)为7.81μg/mL,化合物2和7对金黄色葡萄球菌的MIC值分别为0.49和0.98μg/mL,高于阳性对照卡那霉素的MIC值(3.91μg/mL)。化合物1～7对于被测试的两株真菌小麦赤霉病菌和玉米小斑病菌没有表现出抑制作用。     

毛筒壳科真菌次级代谢产物生物活性的评价

毛筒壳科Tubeufiaceae真菌具有产新结构、新活性次级代谢产物的潜力,目前对该科真菌次级代谢产物的研究较少。为了寻找具有生物活性的新化合物,有必要对毛筒壳科真菌次级代谢产物及其活性进行系统深入的研究。本文采用平板对峙法、生长速率法和MTT法,分别测定已分离得到的19株该科真菌活体菌株抑菌活性、发酵物抑菌活性以及发酵物粗提物对不同人体肿瘤细胞株增殖的抑制作用。通过平板对峙法,试验共筛选获得13株活性菌株,其中,红棕毛筒腔菌菌株Tubeufia rubra PF02-2对7种植物病原真菌有明显的抑菌效果,抑制率均高于60%且抑菌谱广。采用生长速率法,发现红棕毛筒腔菌菌株PF02-2经液体发酵后,发酵液对其中4种植物病原真菌仍有一定的抑制作用,且菌丝体部分的乙酸乙酯提取物对马铃薯早疫病病菌Alternaria solani（ZYB）的抑制效果最好。通过MTT法,发现发酵物粗提物对3种肿瘤细胞均具有不同程度的细胞毒活性,其中在300μg/mL时,剑叶莎毛筒腔菌菌株Tubeufia machaerinae ML03-2发酵液部分的乙酸乙酯提取物对人宫颈癌细胞株HeLa和人前列腺癌细胞株PC-3的抑制率（%）分别达到了98.92±0.15和97.86±0.18,在400μg/mL时,对人肝癌细胞株HEPG2的抑制率（%）达到了98.88±0.04;在500μg/mL时,明孢新旋卷孢菌菌株Neohelicosporium hyalosporum ML05-1菌丝体部分的乙酸乙酯提取物对人宫颈癌细胞株HeLa细胞的抑制率（%）为98.32±0.02,在600μg/mL时,对人肝癌细胞株HEPG2的抑制率（%）达到了97.62±0.20,在300μg/mL时,对人前列腺癌细胞株PC-3的抑制率（%）达到了98.91±0.02。该研究结果为开发利用毛筒壳科真菌提供了科学依据。     

曲霉属真菌Aspergillus clavatonanicus HNMF114的次生代谢产物及其抗菌活性研究

本文对一株来自中华紫蛤的附生真菌HNMF114进行次生代谢产物的研究。从中分离鉴定了1个新化合物和8个已知化合物。分别鉴定为clavatone(1)、cyclo(L-Trp-L-Trp)(2)、2,4(1H,3H)-quinazolinedione (3)、clavatol(4)、kotanin(5)、orlandin(6)、desmethylkotanin(7)、(S)-2-(1-Hydroxy-2,2-dimethylpropyl)quinazolin-4(3H)-one(8)、(S)-2-methyl-1-(4-oxo-3,4-dihydroquinazolin-2-yl)propyl acetate(9)。新化合物1对大肠杆菌的生长具有一定的抑制作用,最小抑菌浓度(MIC)为2μg/mL。化合物4、9对金黄色葡萄球菌有一定的抑制作用,最小抑制浓度分别为1μg/mL和4μg/mL。化合物5对枯草芽孢杆菌有一定的抑制作用,最小抑制浓度分别为8μg/mL。化合物4、5和9对李斯特菌有一定的抑制作用,最小抑制浓度分别为4、4和8μg/mL。     

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.     

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     

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.