南海珊瑚来源真菌Aspergillus sp.SCSIO 40435的分离鉴定及其次级代谢产物研究

【目的】南海珊瑚共附生真菌Aspergillus sp. SCSIO 40435次级代谢产物分离鉴定及抑菌活性筛选。【方法】利用稀释涂布平板法分离珊瑚共附生真菌。采用单菌多代谢产物方法(one strain many compounds,OSMAC)对分离菌株进行化学多样性筛选,并采用滤纸片扩散法对真菌发酵产物进行抑菌活性分析。通过ITS测序鉴定活性菌株SCSIO 40435的分类地位,运用多种色谱手段从其粗提物中分离纯化单体化合物,并利用各种波谱手段(HRESIMS、1D和2D NMR、单晶X-ray衍射法等)确定化合物的结构。最后,采用微量肉汤稀释法对单体化合物的抑菌活性进行评估。【结果】从南海珊瑚样品中分离得到19株共附生真菌,结合化学多样性和抑菌活性分析,筛选出1株产物丰富且具有多种抑菌活性的菌株SCSIO40435。利用ITS测序分析将其鉴定为曲霉属真菌(Aspergillus sp.),进一步从其发酵产物中分离鉴定了4个对三联苯类化合物：dicandidusin A(1)、candidusin A(2)、terphenyllin(3)和4″-deoxyterphenylli...     

具抑菌活性连翘内生真菌的分离与鉴定

【目的】从药用植物连翘内生真菌中筛选抑菌活性菌株, 并对其主要活性成分进行检测分析。【方法】采用常规组织分离法分离内生真菌, 滤纸片法测定其发酵产物对3种指示细菌的抑菌活性。TLC、HPLC和HPLC-MS检测活性菌株代谢产物中连翘苷成分。根据形态学特征和ITS序列分析鉴定目的菌株。【结果】分离得到的24株内生真菌中抑菌圈直径超过10 mm的菌株, 发酵液组有11株(45.8%), 菌丝体组有19株(79.2%), 活性菌株主要集中在果实内生真菌中, 其中G5、G7和G10表现出较强的抑菌活性。从菌株G10的胞内产物中发现活性成分连翘苷, 将其鉴定为胶孢炭疽菌Colletotrichum gloeosporioides。【结论】连翘内生真菌是天然抗菌活性物质的重要筛选来源。     

基于超高效液相色谱-电喷雾-质谱、天然产物词典和活性筛选的艾纳香内生真菌次生代谢产物

【背景】植物内生真菌是天然活性小分子的重要来源,但由于种类繁多,导致寻找结构新颖、活性强的化合物非常困难,重复分离已成为制约新型药源小分子发掘的瓶颈。【目的】综合各种技术,快速寻找目标活性次生代谢产物。【方法】通过对菌株分子鉴定、天然产物词典(dictionaryofnatural products,DNP)数据库检索、超高效液相色谱-电喷雾-质谱(ultraperformanceliquidchromatographyquadrupole time-of-flight mass spectrometry,UPLC-QTof-MS)分析、滤纸片法抑菌实验和色谱技术跟踪获得活性单体化合物。运用质谱和单晶衍射技术对化合物结构进行鉴定,96孔板法对单体化合物进行活性评价。【结果】分离鉴定出11株艾纳香内生真菌,筛选出一株各方面表现良好的艾纳香内生菌菌株Diaporthe sp.,从其大米培养基中获得一个单体化合物Cytochalasin H,活性评价显示其对枯草芽孢杆菌具有很好的抑制活性,MIC值为32μg/mL。【结论】将多种筛选技术相结合的方法应用于艾纳香内生真菌活性代谢产物的发掘,为快速寻找活性先导化合物提供了很好的借鉴。     

湛江高桥红树林沉积物放线菌多样性及其中一株链霉菌产生的germicidins类化合物的鉴定

【目的】从3种红树林植物根际沉积物中分离和鉴定放线菌,进行抑菌活性初筛获得目标菌株并研究其次级代谢产物。【方法】使用5种培养基对红树林植物根际沉积物放线菌进行分离,采用16S rRNA基因序列比对的方法研究沉积物中的放线菌多样性,结合抑菌活性筛选获得目标菌株后进行放大规模发酵和分离鉴定次级代谢产物,根据生物合成基因簇定位和分析对化合物的生物合成途径进行推导。【结果】从3种红树林植物根际沉积物中分离得到放线菌49株,包括链霉菌属(Streptomyces)31株、小单孢菌属(Micromonospora)14株、小双孢菌属(Microbispora)、链孢子囊菌属(Streptosporangium)、野野村氏菌属(Nonomuraea)和糖单孢菌属(Saccharomonospora)各1株。获得粗浸膏抑菌活性较好的菌株Streptomyces sp. SCSIO 40067,从中分离鉴定了6个α-吡喃酮类化合物：germicidin A–C、germicidin I和isogermicidin A–B,并首次报道了germicidin A的晶体结构。从菌株SCSIO 40067基因组...     

地衣内生菌Elaphocordyceps sp.的代谢产物

【目的】通过对猫耳衣内生菌Elaphocordyceps sp.代谢产物的研究,以期获得结构新颖、抗菌活性强的化合物。【方法】采用PCR扩增和测定nrDNA的ITS(Internal transcribed spacer)序列,在GenBank数据库中比对,并采用构建系统发育树的方法,确定该菌株的分类地位。采用硅胶柱色谱、凝胶柱色谱和高效液相色谱方法进行成分分离。根据理化性质和波谱数据进行结构鉴定。采用倍比稀释法进行抑菌活性测定。【结果】鉴定出供试菌株为地衣内生菌Elaphocordyceps sp.。从Elaphocordyceps sp.的发酵液中分离得到3个化合物,结构鉴定为麦角甾醇、4,8-Dihydroxy-1-tetralone和De-O-methyldiaporthin。化合物1–3表现弱的抑制白色念珠菌活性。化合物3具有非常强的植物毒活性(叶片敏感度:4 nmol)。化合物3在地衣内生菌Elaphocordyceps sp.发酵液中的得率为0.75 mg/L(3.2?103 nmol),远远高于其对叶片敏感度4 nmol。【结论】由猫耳衣内生菌Elaphocordyceps sp.产生的De-O-methyldiaporthin可作为一种微生物源除草剂。     

北桑寄生内生真菌的分离及其次级代谢产物分析

首次对药用植物北桑寄生叶片中的内生真菌进行分离纯化,从中筛选出具有较高生物活性的菌株,鉴定此菌株并对其次级代谢产物进行初步分离。采用组织块法分离内生真菌,对其进行抗氧化活性和抑菌活性筛选;通过形态学和分子生物学方法鉴定其种属;运用柱色谱、重结晶等方法分离次级代谢产物,波谱学鉴定其结构。从北桑寄生叶片中分离纯化得到29株内生真菌,检测得到一株具有较高抗氧化和抑菌活性的菌株,鉴定为Alternaria alternata,从该菌次级代谢产物中首次分离得到3个单体化合物,分别为alternariol-5-O-methyl ether(1)、alternariol(2)、cis,cis-9,12-octadecadienoic acid(3)。化合物1和2具有较弱的抗氧化活性,化合物1和3表现出一定的抑菌活性。     

艾纳香内生真菌Diaporthe sp.次生代谢产物

【目的】从艾纳香内生菌J1中获得活性次生代谢产物。【方法】对菌株J1进行ITS序列分子鉴定,综合运用多种色谱技术对其发酵产物进行分离纯化,结合波谱学技术对其进行结构表征。【结果】经构建系统进化树,鉴定菌株J1为Diaporthe sp.,从该菌株大米培养基中分离得到7个单体化合物,经鉴定分别为Dicerandrol A (1)、Dicerandrol B (2)、4,6-dihydroxy-1H-isoindole1,3(2H)-dione (3)、Cytochalasin H (4)、Cytochalasin J (5)、4,6-dihydroxy-2,3-dihydro-1H-isoindol-1-one (6)、Cerebroside C (7)。所有化合物均为首次从该菌中分得,化合物1对枯草芽孢杆菌Bacillus subtilis KCTC 1021具有非常强的抑制活性,MIC值为0.125μg/mL。【结论】Diaporthe sp.富含抑菌活性化合物,具有开发成微生物源农药潜力。     

东乡野生稻内生放线菌分离及菌株S123次级代谢产物分析

【目的】从东乡野生稻(Oryza rufipogon)中分离和鉴定内生放线菌,对其进行抗菌活性筛选,并分析高抗菌活性菌株S123的次级代谢产物。【方法】采用S培养基对东乡野生稻内生放线菌进行分离、纯化,并构建16S rRNA基因序列系统发育进化树进行菌株鉴定。以琼脂扩散法和菌丝生长速率法进行抗菌活性筛选,同时设计简并引物检测菌株I型聚酮合酶(PKS-I)基因。对具广谱抗菌活性的菌株S123进行分批大量发酵,运用多种色谱方法对发酵产物进行分离、纯化,利用MS和NMR分析鉴定化合物的结构。【结果】从东乡野生稻中共分离到11株内生放线菌,分别属于链霉菌属(8株)和假诺卡氏属(3株)。其中有8株具有抗菌活性,8株呈现I型PKS阳性。从高抑菌活性菌株S123中分离到化合物Nigericin和17-O-demethylgeldanamycin,其中Nigericin对金黄色葡萄球菌、枯草芽孢杆菌及水稻纹枯病菌均有抑制活性。【结论】对东乡野生稻内生放线菌进行了分离、鉴定和抗菌活性筛选,并从中分到两种与I型PKS基因相关活性的化合物Nigericin和17-O-demethylgeldanamycin,为研究东乡野生稻内生放线菌的多样性和次级代谢产物的分离提供依据。     

抗副溶血弧菌海洋真菌HL-3菌株的鉴定及其活性物质的分离

【背景】目前水产养殖中副溶血弧菌等水产致病菌的预防和治疗主要使用的是抗生素,短期内能够起到较好的效果,但是长期使用抗生素不仅使得病原菌的耐药性增加,而且会产生一系列问题。因此,寻找安全有效的抗生素替代品迫在眉睫。【目的】筛选具有抗副溶血弧菌活性的海洋微生物,鉴定其种类并优化其培养条件,并对其活性物质进行初步分离。【方法】利用稀释涂布平板法和平板划线法分离纯化海洋微生物,通过牛津杯法筛选具有抗副溶血弧菌活性的菌株。根据菌株的形态特征和ITS序列分析对活性菌株进行鉴定。通过筛选培养基种类和盐度确定其培养条件。通过半制备高效液相色谱制备化合物,并利用核磁共振波谱数据鉴定化合物的结构。【结果】从海螺、小黄鱼、对虾等11种样品中分离出海洋微生物菌株76株,其中真菌26株。筛选得到一株具有抗副溶血弧菌活性的真菌菌株HL-3,鉴定为黄曲霉。黄曲霉HL-3菌株在改良沙氏培养基条件下,产物化学多样性和抗菌活性较好。黄曲霉HL-3菌株在真菌5号培养基中产物单一且抗菌活性较好,纯化出来的化合物结构被鉴定为曲酸。曲酸对副溶血弧菌的最小抑菌浓度为4.0mg/mL。【结论】实验结果为进一步利用各种色谱手段分离纯化...     

芍药内生真菌的鉴定及产生活性次生代谢产物的评估

【目的】研究药用植物芍药(Paeonia lactiflora Pall.)内生真菌的种群多样性,同时对其可能存在的聚酮合酶(Polyketide synthase,PKS)和非核糖体多肽合成酶(Non-ribosomal peptide synthetase,NRPS)基因多样性进行评估,预测芍药内生真菌产生活性次生代谢产物的潜力。【方法】采用组织分离法获得芍药根部内生真菌菌株,结合形态学特征和ITS序列分析,进行鉴定;利用兼并性引物对内生真菌中存在的聚酮合酶(PKS)基因和非核糖体多肽合成酶(NRPS)基因进行PCR扩增及序列测定分析,构建系统发育树,明确芍药内真菌PKS基因序列和NRPS基因序列的系统进化地位。【结果】从芍药组织块中共分离得到105株内生分离物,去重复后获得52株内生真菌,菌株ITS基因序列信息显示,52株芍药内生真菌隶属于7目、13科、15属,其中小球腔菌属(Leptosphaeria)、土赤壳属(Ilyonectria)和镰孢属(Fusarium)为优势种群;从52株内生真菌中筛选获得13株含PKS基因片段的菌株,8株含NRPS基因片段的菌株,部分菌株功能基因的氨基酸序列与Gen Bank中已知化合物的合成序列具有一定的同源性,预示芍药根部内生真菌具有合成丰富多样的次生代谢产物的潜力。【结论】药用植物芍药根部具有丰富的内生真菌资源,且具有产生活性次生代谢产物的潜力,值得进一步开发研究和应用。     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Apoptotic Regulation of Caspase Activity

Intracellular cysteine aspartate-specific proteases (caspases) play both signaling and effector roles in realizing the program of cell death. Caspases function as proteolytic cascades unique for each cell type and signal triggering apoptosis. All parts of the proteolytic cascades are duplicated and controlled by feedback signals. Amplification cycles between pairs of caspases (the third and the sixth, the ninth and the third, the twelfth and the sixth, and others) help multiply the initial apoptotic signal. The presence of physiological inhibitors of apoptosis that directly interact with caspases creates a multilevel regulatory network of apoptosis in cell. The caspase proteolytic cascades are also regulated by sphingolipid secondary messengers, among them ceramide, sphingosine, and their phosphates. Moreover, an association of the caspase signaling with ubiquitin-dependent proteolysis is shown in cells. In particular, the use of extracellular activators and inhibitors of caspases allows irreversible activation of apoptosis in tumor cells or the prevention of apoptosis in cortical neurons under neurodegenerative diseases.     

Analysis of twin of eyeless regulation during early embryogenesis in Drosophila melanogaster

The Drosophila Pax6 homolog twin of eyeless (toy) is so far the first zygotically expressed gene involved in eye morphogenesis in Drosophila. The study of its expression during embryogenesis is therefore informative of the initial events of eye development in Drosophila. We have analyzed how the initial expression domain of toy at cellular blastoderm is regulated. We show that the three maternal patterning systems active in the cephalic region (the anterior, terminal and dorsal-ventral systems) cooperate with zygotically activated gap genes to shape the initial expression domain of toy. Whereas Bicoid, Dorsal and Torso signaling synergistically act as activators, Hunchback, Knirps and Decapentaplegic act as repressors.     

New species of Peruvian Orchidaceae III

Sixteen new species are proposed in the generaAckermania, Dressleria, Epidendrum, Maxillaria, Oncidium, Rodriguezia, Sigmatostalix, andTrigonidium. All new species are illustrated.Maxillaria vittariifolia L. O. Williams is newly recorded for Peru. A key is provided forTrigonidium of Peru.Trigonidium loretoense Schltr. andT. peruvianum Schltr. are lectotypified.     

Host plants of someRhinanthoideae (Scrophulariaceae) of eastern North America

Twenty three species in 11 genera were examined in the field to determine hosts. OnlyStriga asiatica andSeymeria cassioides have a narrow host range being restricted to grasses and pines, respectively. These are the only species which cause pronounced and sometimes serious host damage. The other species attach to a great diversity of hosts.     

广西青藓科分类学修订

通过对采自广西24个县(市)的1 147份青藓科植物标本的逐一鉴定及相关文献的查阅,确认有广西青藓科植物11属、44种,其中包括广西青藓科植物新记录属1属,即拟异叶藓属(Pseudokindbergia),新记录种7种,分别为匐枝青藓(Brachythecium procumbens)、阔叶尖喙藓(Oxyrrhynchium latifolium)、泛生尖喙藓(O. vagans)、拟异叶藓(Pseudokindbergia dumosa)、华东细喙藓(Rhynchostegiella sinensis)、长肋拟青藓(Sciurohypnum populeum)和弯叶拟青藓(S. reflexum)。该文提供了修订后的广西青藓科植物名录,并对其中的新记录属、种的主要形态学识别特征、生境和地理分布等进行了详细描述。     

In vitro appraisal of the probiotic value of intestinal lactobacilli

Lactobacilli play a distinctive role in the microbial balance of the chicken gut. In experiments simulating the chicken crop, the antagonism of lactobacilli against Enterobacteriaceae and Salmonella typhimurium was demonstrated and was attributed to lactic acid production. Moreover, adhesion to the crop epithelium was a common characteristic of intestinal lactobacilli. As opposed to salmonellas, lactobacilli were sensitive to deconjugated bile salts at 2.5mm. This sensitivity could lower their chance of proliferation in the small bowel of the chicken tract.The authors are at the Laboratory of Microbial Ecology, Faculty of Agricultural Sciences, State University of Gent, Coupure L., 653, B-9000 Gent, Belgium.