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1.
短小芽胞杆菌HLK8-1的分离鉴定及抑菌特性分析   总被引:1,自引:0,他引:1  
从海南翁田镇凡纳滨对虾(Litopenaeusvannamei)养殖场筛选获得1株能抑制副溶血弧菌(Vibrio parahaemolyticus)等多种病原菌的芽胞杆菌HLK8-1。经形态特征分析、16S r DNA序列分析及Biolog微生物自动鉴定系统鉴定为短小芽胞杆菌(Bacillus pumilus);菌株生长及抑菌性能研究表明该菌株抑菌物质主要产生在生长对数期及平台期;相对于盐度及初始p H等因素,该菌株的抑菌性能受温度影响较大;菌株在p H值范围为7.0~8.5,盐度范围为0~0.2%,温度为30℃等条件下表现出较高的生长水平及抑菌性能;共培养试验表明该菌能将水体中的副溶血弧菌数量控制在较低水平,培养24 h时实验组105cfu/m L,而对照组108cfu/m L。该菌抑制多种水产病原菌,对水体环境耐受能力强,具有防治水产养殖病原菌的应用潜力,且易于培养,抑菌物质分泌到胞外便于分离提取,亦具有发酵工程应用潜力。  相似文献   

2.
拮抗Bacillus subtilis的筛选及发酵条件对拮抗能力的影响   总被引:1,自引:0,他引:1  
筛选了3株对大肠埃希菌具有拮抗活性的枯草芽胞杆菌,并对这3个菌株的拮抗能力最强的Bf菌株的发酵条件进行了初步研究。先将不同枯草芽胞杆菌菌株与株大肠埃希菌进行拮抗试验,根据抑菌率,筛选出对大肠埃希菌拮抗效果较好的枯草芽胞杆菌Bf。然后,在不同pH值、温度以及不同的培养时间下观察记录Bf对大肠埃希菌的拮抗作用。根据实验结果分析得到:筛选到的枯草芽胞杆菌在pH值为7.0,37℃下培养40 h后抑菌效果最好。  相似文献   

3.
目的 筛选向日葵枯萎病拮抗芽胞杆菌菌株并研究其抗菌谱,探讨环境条件对菌株抑菌活性的影响并通过植物栽培完成生防评价。 方法 从向日葵根际土壤中选择性分离芽胞杆菌,通过5点对峙法确定1株高效拮抗菌株,进行鉴定后,测定其抑菌谱;单因素实验探讨环境条件对抑菌活性的影响;向日葵发芽实验完成生防评价。 结果 确定1株高效的枯萎病拮抗菌株WBFL-1,经鉴定为枯草芽胞杆菌,该菌对镰刀菌属具有广谱抗性,其抑菌活性的最佳条件是温度40 ℃,pH值7.0,接种量150 μL,发酵时间48 h。生防评价表明该菌对枯萎病的拮抗效果显著。 结论 该菌可为农作物枯萎病的生物防治提供有效菌种储备。  相似文献   

4.
目的:芽孢杆菌dhs-330分离自海水,能够产生脂肽-糖脂混合型表面活性剂。考察该菌株产物的抑菌性能。方法:采用抑菌圈法考察dhs-330发酵液对不同指示菌的抑菌活性,对提取的dhs-330产物进行最小抑菌浓度(MIC)测定,并考察该产物对温度、盐度和pH值的稳定性。结果:菌株dhs-330产物对嗜水气单胞菌、枯草芽孢杆菌、短小芽孢杆菌和金黄色葡萄球菌有抑菌作用,MIC分别为0.005、0.01、0.01和0.02 g/L;经100℃处理20 min、pH2~10处理30 min,或盐度为0~50的条件下,产物仍具有抑菌活性或略有下降。结论:海洋来源的芽孢杆菌dhs-330胞外脂肽-糖脂混合型产物具有抑菌活性,且在高温、低pH值和高盐度条件下具有稳定性。  相似文献   

5.
对筛选自中国南海、黄海、渤海4个地区近海海水样品的7株有抗白念珠菌活性,且稳定性较强的芽胞杆菌的形态特征、培养特征及生理生化试验等进行系统分析比较,结果表明,LU-B02为凝结芽胞杆菌(Bacillus coagulans),LU-B13为蜡样芽胞杆菌(Bacillus cereus),其他各菌株为短小芽胞杆菌(Bacillius pumilus),除LU-B02耐盐度5%外,其他耐盐度达10%以上。它们均属于芽胞杆菌的第一群。16S r DNA基因同源性序列比较进一步证实LU-B02为凝结芽胞杆菌,它与凝结芽胞杆菌标准菌株ATCC15950在鉴定特征上虽然相同,但与后者相比,最高生长温度较低,耐盐性较强,可以利用阿拉伯糖、木糖、甘露醇等碳源,可水解酪素,并可稳定地产生抗白念珠菌活性物质,将其命名为Bacillus coagulans subsp.heishijiaosis。尚未见抗白念珠菌的凝结芽胞杆菌菌株的有关报道。  相似文献   

6.
旨在扩大苏云金芽胞杆菌(Bacillus thuringiensis,Bt)的生防范围,通过对Bt LTS290菌株的对峙培养和菌株无菌发酵液对镰孢菌的抑制作用进行研究。结果表明,Bt LTS290菌株可抑制6种马铃薯致病镰孢菌的生长,并且Bt LTS290无菌发酵液的抑菌效果显著。抑菌物质对温度不敏感,经过121℃处理20 min后仍然具有抑菌活性。在p H3-11范围内存放12 h后,抑菌活性变幅不大,并且用蛋白酶K处理后其抑菌活性依然存在。实验证明苏云金芽胞杆菌Bt LTS290是一株可以高效抑制马铃薯致病镰孢菌的生防菌株。  相似文献   

7.
为分离筛选具有广谱抑菌作用的细菌并研究其抗菌物质,实验利用琼脂扩散法和牛津杯法,以溶壁微球菌、金黄色葡萄球菌、铜绿假单胞杆菌、大肠埃希菌为指示菌,从渤海湾大连海域仿刺参养殖圈中分离筛选出9株活性菌,2株具有广谱抑菌效果,其中1株抑菌效果最强.通过形态学和分子生物学检测分析,鉴定该菌株为贝莱斯芽胞杆菌(Bacillus ...  相似文献   

8.
鸡肠源芽胞杆菌的分离、鉴定和抗菌活性   总被引:1,自引:1,他引:0  
从人工饲养的健康三黄肉鸡的盲肠和大肠中分离出10株芽胞杆菌,对其进行菌落形态观察、革兰染色、芽胞染色和生理生化特性鉴定,确定为枯草芽胞杆菌、地衣芽胞杆菌、蜡状芽胞杆菌、巨大芽胞杆菌、球形芽胞杆菌、短小芽胞杆菌、凝结芽胞杆菌。同时测定了它们对动物病原性大肠埃希菌和链球菌的抑菌活性。其中有9株芽胞杆菌对大肠埃希菌有抑制作用,8株芽胞杆菌对链球菌有抑制作用。结果表明芽胞杆菌分离株Y2、Y3、Y4、Y5、Y6、Y7、Y8具有作为益生菌开发的潜力。  相似文献   

9.
徐菁菁  孟竹  王琦 《菌物研究》2015,13(1):15-19
以金黄色葡萄球菌、蜡状芽胞杆菌、枯草芽胞杆菌、大肠杆菌、鼠伤沙门氏菌及肠炎沙门氏菌为测试菌种,对从西洋参(Panax quinquefolium L.)的茎和叶中分离得到的36株内生真菌进行抑菌活性试验,并测定活性菌株的代谢产物和不同极性物质对测试病菌的抑菌活性。试验筛选出2株具有明显抑菌活性的内生真菌,它们的代谢产物和不同极性物质对金黄色葡萄球菌和蜡状芽胞杆菌的抑菌效果最佳,其中胞外多糖和正丁醇提取物的抑菌效果较好。  相似文献   

10.
短小芽胞杆菌Bacillus pumilus HR10是1株优良的菌根辅助细菌(Mycorrhiza Helper Bacteria,MHB),无论单独接种或与外生菌根真菌(Ectomycorrhizal Fungi,EMF)黄色须腹菌(Rhizopogen luteous)互作,都能显著促进马尾松(Pinus massoniana)的生长。应规模应用需要,从10种碳源、8种氮源及8种无机盐中以单因素试验初步筛选出主要组分,在此基础上采用正交试验及响应面分析法优化短小芽胞杆菌HR10增殖扩繁的培养基成分。结果表明,该菌株增殖扩繁培养基最佳组分配比为黄豆粉10.332 g/L,玉米粉7.296 g/L,蛋白胨10.718 g/L,KCl 2.5 g/L,KH2PO42.5 g/L。研究结果为菌根辅助细菌短小芽胞杆菌B.pumilus HR10菌剂开发应用提供了参考依据。  相似文献   

11.
随着基因测序技术的发展,人类获得了大量有关链霉菌次级代谢产物合成基因簇的信息,通过合理的构建策略可以激活其中的隐性基因簇或提高基因簇的表达水平,从而获得新的链霉菌次级代谢产物,或显著提高已知次级代谢产物的发酵水平。从基因表达调控、转座子突变、合成生物学方法、组学方法等四个方面,综述了提高链霉菌次级代谢产物产量的构建策略及其研究进展。  相似文献   

12.
付域泽  焦帅  张乃锋 《微生物学通报》2022,49(12):5184-5193
【背景】人类和动物消化道内栖息着极其复杂和多样化的微生物群落,这些微生物群落分布在肠道的不同位置并执行着特定的功能。近年来,产丁酸菌逐渐成为微生物领域的研究热点,产丁酸菌主要为产芽孢革兰氏阳性厌氧菌,对肠道健康有重要意义。【目的】从反刍动物瘤胃中筛选出产丁酸菌株并研究其生长特性,进一步优化其培养条件,从而提高产丁酸菌的丁酸产量。【方法】以绵羊瘤胃内容物为样品,运用稀释涂布法进行产丁酸菌的筛选,通过形态学观察和16S rRNA基因序列分析等方法对菌株进行鉴定。通过单因素试验与Box-Behnken design试验相结合,对培养条件进行优化,确定筛选菌株在梭菌增殖培养基(reinforced clostridium medium,RCM)中的最佳产酸培养条件。【结果】经过筛选鉴定得到的菌株为梭菌属的拜氏梭菌(clostridium beijerinckii,CB),命名为拜氏梭菌R8(CB.R8)。对拜氏梭菌R8的培养条件进行优化,得出该菌株在接种量为1.22%、温度为38.45℃、pH6.08和培养时间为64.67h的条件下丁酸产量为2.48g/L。【结论】筛选到1株拜氏梭菌R8,该菌能够在RCM培养基中生长并代谢产生丁酸,具备较高的应用价值。  相似文献   

13.
通过比较四种品系小鼠对炭疽芽胞杆菌(Bacillus anthracis)(简称炭疽杆菌)弱毒株芽胞的敏感性,确定炭疽杆菌弱毒株芽胞攻毒合适的动物模型。采用炭疽杆菌弱毒株A16Q1(pXO1-、pXO2+)和A16PI2(pXO1+、pXO2-)的芽胞对四种品系小鼠(DBA/2、KM、ICR和BALB/c)进行腹腔攻毒,记录小鼠死亡时间,计算LD50、绘制存活曲线并统计分析。运用较敏感的KM小鼠研究不同canSNP基因型毒素缺陷株(含pXO2拷贝数不同)芽胞的毒力差异。利用更为敏感的DBA/2小鼠评价S-层蛋白BA3338对荚膜缺陷株芽胞毒力的影响。结果表明,在四种品系小鼠中,毒素缺陷株芽胞的毒力均高于荚膜缺陷株芽胞的毒力。DBA/2小鼠对炭疽杆菌弱毒株芽胞的剂量依赖关系最好,最为敏感,其次是KM小鼠,而ICR小鼠和BALB/c小鼠对炭疽杆菌弱毒株芽胞不敏感。确定了DBA/2小鼠和KM小鼠在炭疽杆菌弱毒株芽胞研究中的适用性。使用KM小鼠评价了不同canSNP基因型炭疽杆菌芽胞的毒力差异,结果表明,不同canSNP基因型炭疽杆菌由于所含pXO2质粒拷贝数的差异导致芽胞的毒力不同。使用DBA/2小鼠评价了S-层蛋白BA3338缺失对炭疽杆菌芽胞毒力的影响,表明BA3338基因的缺失导致炭疽杆菌芽胞毒力降低。  相似文献   

14.
The maleylacetate reductase of 3-chlorobenzoate-grown cells of Pseudomonas sp. strain B13 has been purified 50-fold. The enzyme converted 2-chloromaleylacetate to 3-oxoadipate with temporary occurrence of maleylacetate; 1 mol of chloride was eliminated during the conversion of 1 mol of 2-chloro- and 2,3-dichloromaleylacetate; 2 mol of NADH were consumed per mol of 2-chloro- and 2,3-dichloromaleylacetate while only 1 mol was necessary to catalyze the conversion of maleylacetate or 2-methylmaleylacetate. The maleylacetate reductase failed to use fumarylacetate as a substrate. The role of the enzyme in the chloroaromatics degradation is discussed.  相似文献   

15.
Small cryptic plasmids of molecular weights ranging from 1 to 3 Mdal were detected by electron microscopy in Salmonella typhimurium strain LT2 (ColIb). They were divided into different size classes. Two of the cryptic plasmids were transferred simultaneously with ColIb to Escherichia coli.List of Abbreviations TES buffer 0.05 M tris-HCl pH 8.0, 0.05 M NaCl, 0.005 M Na2 EDTA - TCG medium tris-casamino acid-glucose medium - cpm counts per min  相似文献   

16.
Summary The organisation of the rRNA genes in the chloroplast genomes of two strains of Euglena gracilis were analyzed and compared. It was previously shown that the bacillaris strain contains three complete rrn (rRNA) operons (7) and that the Z-S strain contains one operon (21). Using heteroduplex analysis it was found that the bacillaris strain contains, apart from the three complete rrn operons, an extra 16S rRNA gene, an extra partial 23S rRNA gene sequence and an inverted duplication of a stretch within the 5S–16S spacer. In addition a short (<100 bp) inverted repeat sequence (13) which forms a stem/loop structure in single-stranded cpDNA was located between the 3-end of the extra 16S rRNA gene and the partial 23 S rRNA sequence.The Z-S strain differs from the bacillaris strain by a deletion of two units of the complete rrn operons. The region upstream of the single complete rrn operon, including the inverted repeats, the partial 23S and the extra 16S rRNA sequences is identical with the bacillaris strain.The only non-homology found in heteroduplexes between the SalI fragments of B of the two strains is the deletion-insertion loop which represents the two rrn operons. A small deletion loop was found occasionally in hetero-and in homoduplexes of both strands in the region of variable size. Apart from the deletion/insertion of two rrn operons the two genomes appear to be colinear as can be seen from partial denaturation mapping. The organisation of the rRNA genes of the two strains is compared with those of the Z strain and the bacillaris-ATCC strain.  相似文献   

17.
The degradation of 3,5-dichlorocatechol by enzymes of 3-chlorobenzoate-grown cells of Pseudomonas sp. strain B13 was studied. The following compounds were formed from 3,5-dichlorocatechol: trans-2-chloro-4-carboxymethylenebut-2-en-4-olide, cis-2-chloro-4-carboxymethylenebut-2-en-4-olide, and chloroacetylacrylate as the decarboxylation product of 2-chloromaleylacetate. They were identified by chromatographic and spectroscopic methods (UV, MS, PMR). An enzyme activity converting trans-2-chloro-4-carboxymethylenebut-2-en-4-olide into the cis-isomer was observed.Abbreviations 3CB 3-chlorobenzoate - 4CB 4-chlorobenzoate - 3,5DCB 3,5-dichlorobenzoate - 2,4D 2,4-dichlorophenoxyacetate - NOE Nuclear-Overhauser-Effect  相似文献   

18.
Delany  I.R.  Walsh  U.F.  Ross  I.  Fenton  A.M.  Corkery  D.M.  O'Gara  F. 《Plant and Soil》2001,232(1-2):195-205
Pseudomonas fluorescens F113 is an effective biocontrol agent against Pythium ultimum, the causative agent of damping-off of sugarbeet seedlings. Biocontrol is mediated via the production of the anti-fungal metabolite 2,4-diacetylphloroglucinol (Phl). A genetic approach was used to further enhance the biocontrol ability of F113. Two genetically modified (GM) strains, P. fluorescens F113Rif (pCU8.3) and P. fluorescens F113Rif (pCUP9), were developed for enhanced Phl production and assessed for biocontrol efficacy and impact on sugarbeet in microcosm experiments. The multicopy plasmid pCU8.3 contains the biosynthetic genes (phlA, C, B and D) and the putative permease gene (phlE) of F113 cloned into the rhizosphere stable plasmid pME6010, independent of external promoters. The plasmid pCUP9 consists of the Phl biosynthetic genes cloned downstream of the constitutive Plac promoter in pBBR1MCS. Introduction of pCU8.3 and pCUP9 into P. fluorescens F113 significantly altered the kinetics of Phl biosynthesis when grown in SA medium. A significant and substantial increase in Phl production by the GM strains was observed in the early logarithmic phase and stationary phase of growth compared with the wild-type strain. In microcosm, the two Phl overproducing strains proved to be as effective at controlling damping-off disease as the proprietary fungicide treatment, indicating the potential of genetic modification for plant disease control.  相似文献   

19.
All five examined strains ofCoprinus cinereus could be clearly discriminated from the strains of five otherCoprinus species by RAPD patterns with 12 of 13 primers. Also one specimen of unknownCoprinus strain was identified to beC. cinereus by this method. The RAPD patterns were similar among the strains in the same species; many common DNA fragments were recognized as well as some strain-specific DNA fragments. Thus all seven strains ofC. cinereus and all four strains ofC. angulatus examined could be distinguished individually. Diakryotic strains showed the combined RAPD patterns of the two monokaryotic strains constituting the dikaryon. The combined RAPD markers observed in the dikaryons were segregated in their basidiospore progeny. All 18 randomly picked progeny showed different combinations of RAPD markers from the parental strains.  相似文献   

20.
We studied the induced response of tomato plants to the green strain and the red strain of the spider mite Tetranychus urticae. We focused on the olfactory response of the predatory mite Phytoseiulus persimilis to volatiles from T. urticae-infested tomato leaves in a Y-tube olfactometer. Tomato leaves attracted the predatory mites when slightly infested with the red strain, or moderately or heavily infested with the green strain. In contrast, neither leaves that were slightly infested with green-strain mites, nor leaves that were moderately or heavily infested with the red strain attracted the predators. We discuss the specific defensive responses of tomato plants to each of the two strains.  相似文献   

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