玉米根系内生细菌种群及动态分析

2000-2002年,先后对辽宁省14个玉米主栽品种进行了根系内主要细菌种群分析．结果表明．玉米内生细菌的主要种群为芽孢杆菌属(Bucillus spp．),此外还包括肠杆菌属、沙雷氏杆菌属、假单胞菌属、黄单胞菌属和棍状杆菌属．其中Bacillus分布最广,已鉴定出8个种,包括枯草芽孢杆菌、巨大芽孢杆菌、蜡状芽孢杆菌、地衣芽孢杆菌、炭疽芽孢杆菌、蕈状芽孢杆菌、短小芽孢杆菌、环状芽孢杆菌．Bacillusspp．总量占根系内生细菌总量比苗期和成株期分别为75．5％和76．6％．内生细菌在不同玉米品种和不同生育期之间存在程度不同的差异．研究发现,品种的遗传背景与其内生细菌的种类和数量显著相关．     

武夷山地衣表生和内生芽孢杆菌种群的多样性

摘要:【目的】分析武夷山地衣表生和内生芽孢杆菌种群的多样性。【方法】从武夷山自然保护区采集扁枝衣属(Evernia)、珊瑚枝属(Stereocaulon)、孔叶衣属(Menegazzia)等分属于7科9属的地衣样品9份,分离地衣表面附生(表生)和内生芽孢杆菌,并根据16S rRNA基因序列同源性对分离得到的芽孢杆菌进行种的鉴定。【结果】未从扁枝衣属、树花属(Ramalina)和茶渍属(Lecanora)的3个样品中分离出表生或内生芽孢杆菌,从另外6个样品中分离出芽孢杆菌34株,分别鉴定为芽孢杆菌属(Bacillus)、类芽孢杆菌属(Paenibacillus)、短芽孢杆菌属(Brevibacillus)、赖氨酸芽孢杆菌属(Lysinibacillus)和绿芽孢杆菌属(Viridiibacillus)的24个种。类芽孢杆菌属、芽孢杆菌属是这些地衣表生、内生芽孢杆菌的优势种群,分别占分离得到菌株的41.2%(14株)和35.3%(12株);短芽孢杆菌属、赖氨酸芽孢杆菌属和绿芽孢杆菌属为首次报道从地衣中分离获得。从不同的地衣样品分离的表生和内生芽孢杆菌的种类、数量存在差异。蜈蚣衣属(Physcia)表生的芽孢杆菌数量最多、可达3.85×106 cfu/g,而珊瑚枝属表面附生和内生芽孢杆菌的种类最多、共有12个种。分离到的芽孢杆菌大部分来自单独的一种地衣;台中类芽孢杆菌(Paenibacillus taichungensis)、土壤短芽孢杆菌(Brevibacillus agri)等4个种存在于2－3种地衣中;蕈状芽孢杆菌(Bacillus mycoides)分布最广,在蜈蚣衣属、珊瑚枝属等4种地衣中都有存在。【结论】武夷山地衣表生和内生芽孢杆菌存在种类和数量的多样性。     

嗜热脂肪芽孢杆菌耐热α-淀粉酶基因在大肠杆菌中的克隆和表达

一序言杆菌属是分泌型酶类的重要来源(Priest 1977)。新近有一些队芽孢杆菌属菌种中克隆几种分泌酶类的报道,包括从解淀粉芽孢杆菌(B.amyloliquefaciens),凝结芽孢杆菌(B.Coagulans)和枯草芽孢杆菌(B.Subtilis)中克隆淀粉酶基因,从地衣形芽孢杆菌     

一件出土饱水木漆器文物中可培养细菌的鉴定及对木材的腐蚀作用

【背景】饱水木质文物易受到微生物侵害,目前国外围绕饱水木质文物微生物病害已开展多方面研究,并取得阶段性进展,而国内在饱水木质文物微生物学技术方面的报道比较少。【目的】研究保藏水环境中出土饱水木漆器F446及水中细菌的种类,以及对木材的腐蚀作用。【方法】采用16S rRNA基因序列分析方法及生理生化试验,对饱水木漆器F446及水环境中细菌进行鉴定,并选取典型菌按5×10~8个/瓶菌量接种马尾松心材(悬于无菌自来水中),37°C培养120 d,测试木材的损失率。【结果】从F446文物和水样中分离的53株细菌中,21株被鉴定为芽孢杆菌属(Bacillus),为优势菌属,其中蜡样芽孢杆菌(B.cereus)19株,病研所芽孢杆菌(B.idriensis)和苏云金芽孢杆菌(B.thuringiensis)各1株;11株菌被鉴定为短杆菌属(Brevibacterium),此外还有4株短波单孢菌属(Brevundimonas),5株粪产碱杆菌(Alcaligenes faecalis),5株Altererythrobacter,2株水氏黄杆菌(Flavobacterium mizutaii);另外,还有解糖假苍白杆菌(Pseudochrobactrum saccharolyticum)、梭型芽孢杆菌(Lysinibacillus fusiformis)、Leucobacter aridicollis、Ochrobactrum pseudogrignonense、类芽孢杆菌属(Paenibacillus)菌株各1株。菌株A5、A6分别为类芽孢杆菌(Paenibacillus)和Altererythrobacter属中的疑似新种。从典型菌中选取15株菌回接木材进行腐蚀试验,结果显示,9株细菌与对照组比较存在极显著差异,说明这些菌对马尾松木材有一定的腐蚀作用,但是腐蚀率非常低,最高仅1.38%,表明这些细菌对试验木材马尾松腐蚀并不严重。【结论】F446木漆器文物样品中优势菌属为芽孢杆菌属(Bacillus),水样中优势菌属依次为短杆菌属(Brevibacterium)、短波单孢菌属(Brevundimonas)和Altererythrobacter。从F446木漆器文物和水样中分离出的细菌对木材的降解非常缓慢,短期内腐蚀作用有限。     

白背飞虱雌雄成虫肠道可培养细菌种类组成及差异分析

为弄清白背飞虱成虫肠道细菌组成及雌雄成虫之间的组成差异,本研究采用传统培养法,对云南省元江县水稻田白背飞虱雌雄成虫肠道可培养细菌种类组成进行了分离培养,并采用形态及16S rDNA序列比对方法进行细菌的种属鉴定.结果表明:从白背飞虱肠道内分离鉴定出细菌3门8科12属20种,优势菌门均为厚壁菌门Firmicides(50％),雌成虫肠道优势菌属为葡萄球菌属Staphylococcus(25％),优势菌种为松鼠葡萄球菌Staphylococcus squirrel(25％);雄成虫肠道优势菌属为芽孢杆菌属Bacillus(22％)和微杆菌属Microbacter(22％),优势菌种为产左聚糖微杆菌Microbacterium laevanifoman(22％).其中,雌性成虫肠道内共分离获得细菌3门8科8属12种,包括芽孢杆菌属Bacillus 3种;葡萄球菌属Staphylococcus 1种;微小杆菌属Exiguobacterium 1种;不动杆菌属Acinetobacter 1种;泛菌属Pantoea 1种;假单孢菌属Pseudomonas2种;苍白杆菌属Ochrobactrum 1种;微杆菌属Microbacterium2种.雄性成虫肠道内分离细菌3门8科10属12种,其中梭形杆菌属Lysinibacillus 1种;假杆菌属Fictibacillu 1种;芽孢杆菌属Bacillus 3种;葡萄球菌属Staphylococcus 1种;微小杆菌属 Exiguobacterium1种;肠杆菌属Enterobacter 1种;不动杆菌属Acinetobacter1种;假单孢菌属Pseudomonas 1种;寡养单胞菌属Stenotrophomonas1种;微杆菌属Microbacterium 1种.白背飞虱雌雄成虫肠道内细菌共同种类有4种,分别为松鼠葡萄球菌、乙酰微小杆菌、产左聚糖微杆菌和Acinetobacter soli.该研究将为深入研究白背飞虱肠道细菌功能和雌雄虫肠道细菌组成差异及其机理研究提供理论依据.     

具有ACC脱氨酶活性的海滨锦葵(Kosteletzkya pentacarpos)内生细菌对小麦耐盐性的影响

从盐生植物海滨锦葵块根中分离内生细菌43株,经形态学特征和16S r DNA序列相结合的方法鉴定,分属10个种属,其中芽孢杆菌属是优势属,其次是假单胞菌属和农杆菌属,蜡样芽孢杆菌(Bacillus cereus)和地衣芽孢杆菌(Bacillus licheniformis)是优势种。对海滨锦葵内生细菌ACC脱氨酶活性的测定显示,其中5种菌明显具有ACC脱氨酶活性。用筛选到的5种细菌接种盐胁迫下小麦根系并测定其对于小麦耐盐性的影响。结果表明,蜡样芽孢杆菌、巨大芽孢杆菌(Bacillus megaterium)、短小芽孢杆菌(Bacillus pumilus)、地衣芽孢杆菌四种芽孢杆菌均能显著提高盐胁迫下小麦幼苗的干物质重和叶绿素含量,并能显著提高保护酶(SOD、POD、CAT)活性,对盐胁迫的毒害有一定的缓解作用。绿针假单胞菌(Pseudomonas chlororaphis)对小麦幼苗株高、根长、鲜重、干重、叶绿素含量和保护酶活性的提高也具有一定的作用。上述分析表明从海滨锦葵块根中分离出的5株具有ACC脱氨酶活性的内生细菌均能提高小麦幼苗的耐盐性。     

温室黄瓜叶部微生物区系

采用稀释分离法和消毒叶片研磨液培养法对温室黄瓜叶围和内生微生物进行了分离,共分离到248个菌株,初步鉴定出13个属的叶围真菌,其中链格孢属(Alternaria)和青霉属(Penicillium)真菌为优势类群;鉴定出4个属的内生真菌,其中曲霉属(Aspergillus)真菌为优势类群;10个属的叶围细菌,其中芽孢杆菌属(Bacillus)和黄单胞菌属(Xanthomonas)细菌为优势类群;6个属的内生细菌,其中芽孢杆菌属和假单胞菌属(Pseudomonas)细菌为优势类群;6个属的叶围酵母菌,其中隐球酵母属(Cryptococcus)为优势类群;已鉴定出2个属的叶围放线菌,分别为链霉菌属(Streptomyces)和小多孢菌属(Micropolpspora).未分离到内生酵母菌和放线菌.     

枯草杆菌(Bacillus subtilis)稳定的基因表达系统

芽孢杆菌属(Bacillus)在应用微生物学方面有着悠久的应用历史,尤其是本世纪以来,该属在工业用酶生产中所起的作用愈来愈显重要。液化淀粉芽孢杆菌(B.amyloliquefaciens)曾占据α—淀粉酶工业生产的主导地位,而地衣芽孢杆菌(B.1icheniformis)则是当今世界工业用酶的主要来源之一。     

处理石油化工废水的活性污泥中优势微生物群系及其降解效能的研究

处理石油化工废水的活性污泥中微生物以细菌为主体,霉菌、酵母菌数量较少。分离到167株细菌,主要群系为不动细菌属,假单胞菌属,产碱杆菌属、微球菌属、棒状杆菌属、芽孢杆菌属等、其中大部分菌株对苯酚、苯乙烯、丙酮、甲醇具有降解效能,尤其对苯酚、苯乙烯降解能力较强,菌株数量也较多。     

两种枝顶孢霉胞内细菌的分离鉴定及种群演替

分离、鉴定了枝顶孢霉(Acremonium strictum Gams.)2种胞内细菌,探讨了细菌在其宿主真菌菌丝细胞内的种群演替规律。结果表明,2种胞内细菌分别为不动杆菌Epbas6菌株(Acinetobacter sp.Epbas6)和地衣芽孢杆菌(Bacillus licheniformis)。镜检分析和原始分离物菌落统计表明,不动杆菌和地衣芽孢杆菌的比例为77.5∶1;然而,4℃保藏6个月的真菌分离物中不动杆菌的数量大大减少,地衣芽孢杆菌占据优势,二者的比例变为1∶50.45;而保藏12个月的真菌分离物中只有地衣芽孢杆菌。根据2种细菌的16SrDNA保守序列设计引物,分别扩增了保藏6个月和12个月的枝顶孢霉分离物,发现保藏6个月的分离物能够扩增出2种细菌的保守序列,而保藏12个月的分离物只能扩增出地衣芽孢杆菌保守序列。研究结果说明在枝顶孢霉人工培养和菌种保藏过程中,2种细菌在其宿主真菌菌丝细胞内发生着复杂的生态互作,存在着动态种群演替过程。     

Taxodistines A and B, abietane-type diterpenes from Taxodium distichum

Two new abietane-type diterpenes, taxodistines A (1) and B (2), have been isolated by the guidance of inhibitory effect of tubulin polymerization from the fruits of Taxodium distichum and the structures were elucidated by using 2D NMR data. Taxodistine B (2) showed inhibition of tubulin polymerization.     

New Isoprenylated Phenolic Compounds from Morus laevigata

Two new isoprenylated flavonoids, laevigasins A and B ( 1 and 2 , resp.), and one new isoprenylated 2‐arylbenzofuran, leavigasin C ( 3 ), together with eight known compounds, 4 – 11 , were isolated from the twigs of Morus laevigata. Their structures were elucidated by spectroscopic methods. Laevigasin A ( 1 ) showed significant inhibitory effect on α‐glucosidase in vitro. Notabilisin E ( 5 ), taxifolin ( 10 ), and hultenin ( 11 ) inhibited PTP1B phosphatase activity in vitro.     

瑞香狼毒根中活性物质的分离鉴定及作用机理

以瑞香狼毒根为研究材料,模式植物拟南芥为受体,采用实验室活体生物实验方法研究了瑞香狼毒根提取物及不同极性溶剂萃取物对7 d龄拟南芥幼苗的生长抑制作用;采用活性跟踪的化合物分离方法,分析了其中的活性化合物成分,并通过拟南芥DR5-GUS转基因株系,研究了单体化合物对拟南芥生长发育及根系生长素分布的影响.结果显示,瑞香狼毒根乙醇提取物对拟南芥有很强的生长抑制作用,其乙酸乙酯和氯仿萃取物的抑制活性最为显著,从氯仿萃取物中分离得到两种香豆素类化合物伞形花内酯(1)和西瑞香素(2),其中化合物1能够显著抑制拟南芥幼苗生长及根系发育,且明显降低了根部内源生长素的分布水平;化合物2也有较为明显的抑制活性.研究表明,氯仿和乙酸乙酯萃取物是瑞香狼毒植物毒活性的主要有效部位;伞形花内酯(1)和西瑞香素(2)是瑞香狼毒植物毒活性的有效成分,化合物1对拟南芥生长发育的抑制作用与生长素途径密切相关.     

Differential inhibition of human cytochrome P450 enzymes by epsilon-viniferin,the dimer of resveratrol: comparison with resveratrol and polyphenols from alcoholized beverages

epsilon-Viniferin, a dimer of resveratrol, was isolated in wine at concentration between 0.5 and 5 microM. As resveratrol and polyphenols from red wine were reported to inhibit cytochrome P450 (CYP) activities, this led us to investigate the inhibitory effects of epsilon-viniferin on human CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, CYP2E1, CYP3A4 and CYP4A activities. These effects were compared to those of resveratrol and non volatiles compounds from red wine or various Cognac(R) beverages (enriched with oak-polyphenols). Assays were carried out on human liver microsomes and heterologously expressed CYPs. Ethoxyresorufin, coumarin, benzoxyresorufin, chlorzoxazone, testosterone and lauric acid were used as selective substrates for CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, CYP2E1, CYP3A4 and CYP4A, respectively. epsilon-viniferin displayed a more potent inhibitory effect than resveratrol for all the CYP activities tested (Ki 0.5 to 20 microM vs. 10 to 100 microM, respectively). This effect was not due to an inhibition of the NADPH reductase. A particularly potent inhibitory effect was shown for CYP1A1, CYP1B1 and CYP2B6 which are involved in bioactivation of numerous carcinogens. epsilon-viniferin was not a mechanism-based inhibitor of human CYPs. It displayed, like resveratrol, mixed-type inhibitions for all the CYP tested, except for CYP2E1 (non-competitive). Comparison of the inhibitory effects exerted on CYP activities by epsilon-viniferin, resveratrol and non volatile components from red wine or various Cognac beverages showed that neither resveratrol, nor epsilon-viniferin is the main CYP inhibitor present in red wine solids.     

Two novel steroidal alkaloid glycosides from the seeds of Lycium barbarum

Two novel steroidal alkaloid glycosides, lycioside A (1) and lycioside B (2) were isolated from the seeds of Lycium barbarum. Their structures were determined by various spectroscopic analyses. Compounds 1 and 2 showed inhibitory activities with the IC(50) values of 75.3 and 72.8 μM against rat intestinal sucrase, and 63.4 and 59.1 μM against rat intestinal maltase.     

Structure determination of inonotsuoxides A and B and in vivo anti-tumor promoting activity of inotodiol from the sclerotia of Inonotus obliquus

Two new lanostane-type triterpenoids, inonotsuoxides A (1) and B (2) along with three known lanostane-type triterpenoids, inotodiol (3), trametenolic acid (4), and lanosterol (5), were isolated from the sclerotia of Inonotus obliquus (Pers.: Fr.) (Japanese name: Kabanoanakake) (Russian name: Chaga). Their structures were determined to be 22R,25-epoxylanost-8-ene-3beta,24S-diol (1) and 22S,25-epoxylanost-8-ene-3beta,24S-diol (2) on the basis of spectral data including single crystal X-ray analysis. These compounds except for 2 were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), as a test for potential cancer chemopreventive agents. The most abundant triterpene, inotodiol (3), was investigated for the inhibitory effect in a two-stage carcinogenesis test on mouse skin using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter. Compound 3 was found to exhibit the potent anti-tumor promoting activity in the in vivo carcinogenesis test.     

Variability and interactions between endophytic bacteria and fungi isolated from leaf tissues of citrus rootstocks

Fungi and bacteria were isolated from surface disinfected leaf tissues of several citrus rootstocks. The principal bacterial species isolated were Alcaligenes sp., Bacillus spp. (including B. cereus, B. lentus, B. megaterium, B. pumilus, and B. subtilis), Burkholderia cepacia, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium extorquens, and Pantoea agglomerans, with P. agglomerans and B. pumilus being the most frequently isolated species. The most abundant fungal species were Colletotrichum gloeosporioides, Guignardia citricarpa, and Cladosporium sp. Genetic variability between 36 endophytic bacterial isolates was analysed by the random amplified polymorphic DNA (RAPD) technique, which indicated that B. pumilus isolates were more diverse than P. agglomerans isolates, although genetic diversity was not related to the host plants. In vitro interaction studies between G. citricarpa isolates and the most frequently isolated endophytic bacteria showed that metabolites secreted by G. citricarpa have an inhibitory growth effect on some Bacillus species, and a stimulatory growth effect on P. agglomerans.     

Cryptadines A and B, novel C27N3-type pentacyclic alkaloids from Lycopodium cryptomerinum

Two novel C₂₇N₃-type Lycopodium alkaloids, cryptadines A (1) and B (2) consisting of two octahydroquinoline rings (C₁₁N) and a piperidine ring (C₅N), have been isolated from the club moss Lycopodium cryptomerinum, and their structures and relative stereochemistry were elucidated on the basis of spectroscopic data, chemical transformations, and computational methods. Cryptadines A (1) and B (2) exhibited an inhibitory activity against acetylcholinesterase.     

Two new megastigmane glycosides, physanosides A and B, from Physalis alkekengi L. var. franchetii, and their effect on NO release in macrophages

Two new megastigmane glycosides, physanosides A and B (1 and 2, resp.), were isolated from Physalis alkekengi L. var. franchetii, together with four known compounds (6S,9R)-roseoside (3), (6S,9S)-roseoside (4), (6R,9S)-3-oxo-alpha-ionol beta-D-glucopyranoside (5), and citroside A (6). Their structures were elucidated on the basis of physicochemical evidence, in-depth NMR spectroscopic analysis, high-resolution mass spectrometry, and CD spectroscopy, and their inhibitory effect on NO production was also examined. Compounds 2 and 3 exhibited strong inhibition on lipopolysaccharide-induced NO release by macrophages with IC(50) values of 9.93 and 7.31 microM, respectively.     

Two New Phenol Derivatives from the Cold Seep-Derived Fungus Aspergillus insuetus SD-512

Two new phenol derivatives, namely insphenol A ( 1 ) and acetylpeniciphenol ( 2 ), along with seven known analogs ( 3 – 9 ), were isolated from the deep-sea cold seep-derived fungus, Aspergillus insuetus SD-512. The structures of 1 and 2 were established by extensive interpretation of NMR and mass spectroscopic data. The absolute configuration of 1 was determined by the combination of coupling constant analysis and acid hydrolysis. Among the isolated compounds, insphenol A ( 1 ) represents the first example of isopentenyl phenol derivative with a unique 1-glycosylation from the species Aspergillus insuetus. The isolated new compounds were evaluated for antibacterial activities against six human or aquatic pathogens, while compound 2 exhibited inhibitory effect against Edwardsiella tarda, Vibrio alginolyticus, and V. vulnificus, with MIC values of 4, 8, and 8 μg/mL, respectively.