共查询到20条相似文献，搜索用时 31 毫秒
1.
番茄内生拮抗细菌的分离鉴定及培养条件研究 总被引：1，自引：0，他引：1
针对番茄生产上灰霉病和叶霉病两大瘸害,为寻找安全、高效无污染的生防菌株及其最佳培养条件,本试验采用组织分离法从健康的番茄植株中分离出642个内生细菌菌株,并采用平板对峙法筛选出对番茄灰霉病菌和叶霉病菌拮抗作用强且稳定的两个菌株Thyy1和Jcxy8。通过形态学观察及生理生化特征测定,初步鉴定Jcxy8属环状芽孢杆菌（Bacillus circulans）,菌株Thhy1属枯草芽孢杆菌（Bacillus subtilis）。内生拮抗细菌在以豆饼粉为原料的6号培养基中生长速度快,发酵滤液对两种病原菌的抑制作用强。培养基初始pH值、培养时间、温度、通气量等对菌株生长及其抗菌物质的分泌有明显影响。以豆饼粉培养基、初始pH6．7、培养时问48h、温度30qc、并尽量增大培养通气量为菌株的最佳培养条件。 相似文献
2.
3.
【目的】在田间原位条件下研究丛枝菌根(Arbuscular mycorrhizal, AM)真菌根外菌丝表面有无解磷细菌定殖,并对存在的解磷细菌的种类进行鉴定,对其活化有机磷的能力进行检测,从而为更好地认识菌丝际土壤有机磷的周转和磷的生物地球化学循环过程提供依据。【方法】利用河北省曲周县中国农业大学实验站的玉米长期定位试验,采用田间埋膜方式从玉米根系周围收集AM真菌的根外菌丝,用蒙金娜有机磷固体培养基筛选菌丝表面具有矿化植酸钙能力的细菌,对筛选出的细菌进行分离、 培养,然后提取细菌DNA,通过16S rDNA测序分析来确定解磷细菌的种类。分离鉴定的菌株先用蒙金娜有机磷固体培养基通过测定菌落直径(d)及溶磷圈直径(D)初步鉴定其活化植酸钙的能力,再用无菌的蒙金娜有机磷液体培养基确定每株解磷细菌矿化植酸磷的能力,并对溶液的pH进行测定,每个菌株重复3次。最后采用两室隔网根盒将分离纯化的解磷细菌回接至AM真菌根外菌丝,鉴定回接成功率,确定分离出的解磷细菌能否成功定殖于菌丝表面。【结果】从AM真菌根外菌丝表面分离得到了29株具有活化有机磷能力的细菌,分属于芽胞杆菌、 假单胞菌、 沙雷氏菌、 葡萄球菌和肠杆菌5个不同的属。通过有机磷液体培养进一步检测这些菌株活化植酸磷的能力,发现它们对植酸磷的矿化率为1.9%~21.9%。其中假单胞菌属细菌的解磷能力相对较强,对植酸磷的矿化率达14%以上,液体培养基的pH值下降2~4个单位。将分离纯化的细菌回接至两室隔网根盒的菌丝室,培养30 d后,从菌丝表面再次检测到除假单胞菌属外的芽胞杆菌属(Bacillus)、 沙雷氏菌属(Serratia)、 葡萄球菌属(Staphylococcus)和肠杆菌属(Enterobacter)细菌,另外还检测到贪铜菌属(Cupriavidus)细菌。【结论】在田间原位条件下,与玉米共生的AM真菌的根外菌丝表面有多种解磷细菌定殖,它们活化有机磷能力存在差异,其中以假单胞菌属细菌的解磷能力相对较强。 相似文献
4.
为探明前期分离得到的3株水稻根际耐镉细菌碳源代谢特性,在进行生理生化鉴定的基础上,采用BIOLOG ECO微平板法,分析了3株细菌(菌株A、菌株B和菌株C)的碳源代谢功能。生理生化试验结果表明,3株菌均属于革兰氏阴性细菌,且均具有极生鞭毛,菌株C的生理生化鉴定为铜绿假单胞菌,菌株A与菌株B为假单胞菌属的其他种,结果与之前的分子生物学鉴定结果一致。BIOLOG分析结果表明,3株菌株在培养72 h的AWCD(平均颜色变化率)均接近最大值,在培养24 h时的AWCD存在显著差异,这种差异主要体现在对氨基酸的利用上。在对提供的31种单一碳源利用上,3株菌对N-乙酰-D-葡萄糖胺、L-精氨酸、L-天冬酰胺、甲叉丁二酸、腐胺、4-羟基苯甲酸、丙酮酸甲酯、吐温-40和吐温-80的利用率均较高,且对L-精氨酸、甲叉丁二酸、丙酮酸甲酯的利用率存在显著差异。本研究结果对深入了解耐镉菌株增殖所需要的碳源以及将来优化耐镉细菌最适培养基提供了理论依据,也为构建相应的基因工程菌提供了微生物资源。 相似文献
5.
番茄内生链霉菌S5的分离及其除草活性 总被引：1，自引：0，他引：1
采用植物内生放线菌分离方法从健康番茄（Lycopersicon esculentum）根中分离纯化出58株内生放线菌，从中挑选部分代表性菌株进行代谢产物除草活性检测，发现编号为S5的菌株的代谢产物对小麦（Triticum aesfivum L．）和绿豆（Phaseolus radiatus L．）种子的发芽有强烈的抑制作用，但对发芽后的幼苗生长无明显影响。以百喜草（Paspalum notatum）和狗牙根（Cynodon dactylon）为实验对象，证明S5菌株的代谢产物的确能抑制草籽的发芽，该活性具有潜在的除草效能。经初步鉴定，S5菌株为淡紫灰链霉菌淡青变种（Streptomyces lavendulaevar．glaucescens）。发酵条件实验结果表明，S5菌株在1％葡萄糖和0．3％牛肉膏的S培养基中，以2％接种量在pH7．0和25℃摇床培养，可得到最强的抑制种子发芽的生物活性。 相似文献
6.
从甘蔗根际土壤及甘蔗不同组织内分离到的928个细菌菌株中，对甘蔗黑穗病菌有拮抗作用的细菌菌株有301个．占32．4％．其中拮抗能力强(拮抗带大于10mm)的菌株有18个，占1．9％。经在KBA培养基上培养．发现具有拮抗作用的细菌主要是荧光菌和非荧光菌中的白色菌群。在18个拮抗性强的菌株中，13个菌株来自甘蔗的茎、芽(生长点)，占72％；5个菌株来自根际土壤，占28％；12个菌株为革兰氏阳性细菌中的芽孢杆菌属；6个菌株为革兰氏阴性细菌，其中4个菌株分别为假单胞杆菌属、不动杆菌属、伯克氏菌属及沙雷氏菌属，其余2个菌株有待进一步鉴定。 相似文献
7.
以江汉原油为唯一碳源,经过BH培养基富集培养,以血平板从不同石油污染土壤中分离纯化获得多株细菌.通过测定这些细菌对柴油的乳化程度,发现菌株X13-1具有较强乳化能力,其1 h、24 h的乳化率分别为80%和75%,明显高于文献报道.此外,该菌在以石蜡为唯一碳源的BH培养基中生长较好,说明其具有较强的分解石油的能力.经Biolog细菌自动鉴定仪鉴定,同时进一步通过PCR扩增获得该菌的16SrDNA,并测序.对其16S rDNA分析表明,该菌株与GenBank中的醋酸钙不动杆菌同源性为97%,确定该菌可能为醋酸钙不动杆菌（Acinetobacter calcoaceticus）. 相似文献
8.
提高土壤微生物的可培养性,获得纯培养微生物菌株,是微生物生态学研究的基础。采用三种培养基对土壤细菌进行分时段计数,以细菌通用引物扩增细菌16S rDNA片段,用限制性内切酶HhaI酶切PCR产物,对酶切图谱进行分型,研究不同培养方法对土壤细菌多样性和可培养的影响。结果表明,LB、CSEA、W SA培养基192 h后每g干土获得的细菌数量分别为14.84×107、10.27×107和6.91×107CFU,但微生物多样性指数以W SA为最高,LB多样性指数最低;三种培养基培养的细菌菌群有一定的相似性,LB和CSEA培养基间的Jaccard指数为57.69%,LB和W SA培养基之间为53.13%,而CSEA和W SA培养基的相似性指数达66.67%;16S rDNA测序结果表明,所获得的土壤细菌优势种群在分类方面主要属于γ-和β-变形杆菌以及放线菌亚门,其中某些OTUs中的16S rDNA序列与Burkholderiaceae bacterium、Rhodococcus和Mycobac-terium属具有较高的同源性,推测其细胞能够分泌复苏促进因子,有效地提高土壤细菌的可培养性。 相似文献
9.
为研究接种复合菌剂对堆肥微生物群落变化的影响,以奶牛粪便和稻草为原料进行堆肥试验,设添加复合菌剂BLD（由3株木质纤维素降解细菌组成,经测序鉴定分别为枯草芽孢杆菌、地衣芽孢杆菌、假单胞菌属中未鉴定种）和不加菌剂两个处理,利用传统平板培养与聚合酶链式反应-变性梯度凝胶电泳（PCR-DGGE）方法相结合研究两种堆肥处理对微生物群落演替的影响。结果表明,基于传统培养方式,微生物数量呈升高-降低-升高-降低的趋势,且细菌数量明显大于真菌数量;DGGE图谱显示,两种堆肥处理的条带数呈现与传统培养相似的变化趋势。接种菌株在堆肥初期成功定殖,高温期成为优势菌株,降温期优势逐渐减弱。接种菌剂增加了堆肥中细菌数量,提高了堆肥微生物群落多样性,从而促进堆肥微生物群落演替,缩短堆肥腐熟时间。 相似文献
10.
几株固氮芽孢杆菌的分离与鉴定 总被引：6，自引：0，他引：6
摘要： 从小麦（Triticum aestivum）、玉米（Zea mays）、黑麦草（Lolium sp.）和柳树（Salix sp.）的根际土壤中分离得到能在无氮培养基上生长的29株芽孢杆菌（Bacilli），通过固氮酶活的测定以及固氮酶结构基因 nifH 的PCR扩增得到7株固氮芽孢杆菌。对这7株固氮菌株进行了生理生化性状测定、16S rDNA序列分析(GenBank accession No. AY373358, AY373360,~AY373364和AY376876)、G+C mol%含量的测定及DNA-DNA杂交实验，结果表明，其中5株菌属于芽孢杆菌，另外2株菌属于类芽孢杆菌。在这7株被鉴定的菌株中，菌株T1被鉴定为Bacillus cereus；菌株G1、C4和C5被鉴定为B. megaterium；菌株W5的生理生化性状、16S rDNA和G+C mol%与Bacillus marisflavi 相近；G2的生理生化性状和16S rDNA 与Paenibacillus polymyxa 接近，但在基于16S rDNA的系统发育树中却与P. durus 聚在最小的分支内；T7可能是Paenibacillus属中的一个新种。 相似文献
11.
R.D. Davis 《Soil biology & biochemistry》1976,8(5):429-433
Soil can inhibit or reduce the growth of bacteria in agar discs incubated in contact with it and this bacteriostatic property is broadly similar to fungistasis. It was only operative at low nutrient concentrations and could be removed by adding nutrients to soil or by keeping the discs containing bacteria continually supplied with nutrients during their incubation on soil. The effect was also removed when discs were dosed with nutrients after incubation on soil, and then reincubated away from soil. The bacteriostatic factor is apparently unstable away from soil as it could not be demonstrated in agar discs previously incubated on soil, which were expected to contain inhibitor at operative concentrations. Attempts to demonstrate inhibitory activity in soil extracts, and preliminary experiments to detect volatile inhibitors emanating from soil were also unsuccessful. 相似文献
12.
C Neut J Pathak C Romond H Beerens 《Journal of the Association of Official Analytical Chemists》1985,68(5):881-883
The lactose sulfite (LS) medium recommended for the detection and identification of Clostridium perfringens in foods was compared with a reference method using tryptose-sulfite-cycloserine (TSC) agar for the enumeration of this organism in a variety of foods and food ingredients. C. perfringens was detected and enumerated in 17 of the 54 samples examined with LS broth, but its presence could be confirmed in only 9 of the samples with TSC agar. In only 2 instances, C. perfringens was detected on TSC agar but not in LS broth. A positive response (FeS + and gas +) in LS broth incubated at 46 degrees C always corresponded to the presence of C. perfringens; whereas the black colonies formed on TSC agar incubated at 37 degrees C were frequently found to be Clostridium species other than C. perfringens. Thus, because of its highly selective nature, LS broth was superior to TSC agar for enumerating and confirming the small numbers of C. perfringens that were present in a majority of the samples. This was especially true when other clostridia were also present. Besides its greater selectivity and sensitivity, LS broth had the additional advantages of requiring less work and giving confirmed results within 24-48 h compared with 3 days for the TSC agar method. 相似文献
13.
S L Keelan R S Flowers B J Robison 《Journal of the Association of Official Analytical Chemists》1988,71(5):968-972
Nine laboratories evaluated the ability of the MICRO-ID test system to correctly identify members of the Enterobacteriaceae. A total of 78 isolates representing 11 genera of enterics that had been previously isolated from foods were used in the collaborative study. The collaborators streaked each isolate on plate count agar and incubated the plates overnight at 35 degrees C to check purity of the isolates. Then they proceeded with the method in which an isolated colony is transferred to a plate count agar slant and is incubated 18-24 h at 35 degrees C. Growth from the slant is emulsified in 3.5 mL physiological saline to a density comparable to a McFarland No. 2 tube and is then used to inoculate the test (MICRO-ID) strip. The strip is incubated 4 h at 35 degrees C and the reactions are read and recorded. Isolates are identified by using an octal code and the test kit manual. The system correctly identified 98.8% of the Salmonella isolates, 97.7% of the E. coli isolates, and 84.6% of the other 9 enteric genera tested. The system has been approved interim official first action as an alternative to conventional biochemical tests (1) for presumptive generic identification of food-borne Salmonella and for screening and elimination of non-Salmonella isolates; (2) for identification of E. coli from foods; and (3) for presumptive generic identification of other Enterobacteriaceae isolated from foods. 相似文献
14.
M T Knight D W Wood J F Black G Gosney R O Rigney J R Agin C K Gravens S M Farnham 《Journal of the Association of Official Analytical Chemists》1990,73(5):729-733
Twelve laboratories evaluated the Gram-Negative Identification (GNI) Card to identify members of the Enterobacteriaceae. Eighty-four isolates, previously isolated from foods, were used in the collaborative study; the isolates represented 12 genera within the Enterobacteriaceae group. Each collaborator streaked each isolate on tryptic soy agar plates for purity. In the method, plates are incubated 18-24 h at 35 degrees C. Isolated colonies are then subcultured to tryptic soy agar slants and incubated 18-24 h at 35 degrees C. An emulsion is made from the growth on the slant in 1.8 mL 0.45% sodium chloride solution. The GNI Card is filled and placed in a reader/incubator. Isolates are identified and an identification is printed. The Vitek System correctly identified 96.7% of Salmonella sp., 97.0% of Escherichia coli, and an average of 93.8% of the other enteric genera. The method using the Vitek System and GNI Card has been approved interim official first action by AOAC as a screening method for the presumptive identification of Salmonella sp., E. coli, and other Enterobacteriaceae isolated from foods. 相似文献
15.
Göran Bengtsson 《Soil biology & biochemistry》2004,36(6):999-1008
We examined the stability of plasmid RP4 and its expression of antibiotic-resistance genes in suspended and sorbed Pseudomonas putida in aquifer microcosms. Test tubes containing different proportions of sterilized aquifer soil and groundwater were inoculated with bacteria and incubated for up to 26 d. Serial dilutions were made to agar plates with or without antibiotics, to quantify the functional stability of the plasmid. The structural integrity of RP4 was examined by plasmid extraction, digestion with restriction enzymes, and agarose gel electrophoresis. The plasmid-borne resistance gene expression disappeared in 80-90% of the cells during day 1 of incubation in aquifer soil and then remained at that frequency throughout the experiment. The RP4 plasmid was present in cells without antibiotic-resistance gene expression, indicating that the observed loss of plasmid-encoded activity was most likely due to a reduction in expression of the resistance genes. The increased growth rate in groundwater amended with glucose and phosphate had no significant influence on plasmid loss or antibiotic-resistance expression, suggesting that plasmid loss and antibiotic-resistance expression were independent of the growth rate. Most of the reduction of resistance gene expression was associated with the presence of soil particles, and 70% of the resistance expression was retained in bacteria incubated for 1 d in groundwater alone. Bacteria sorbed to the soil particles had a lower frequency of expression of resistance genes than suspended bacteria, but the difference was not caused by sorbed inorganic or organic chemicals. Resistance gene expression was partly recovered in suspended bacteria after in vitro exposure to the antibiotics and after first isolating on agar without antibiotics and then replica plating to agar containing the antibiotics. 相似文献
16.
THE EFFECT OF TEMPERATURE ON THE MICROBIAL TRANSFORMATION OF [14 C] GLUCOSE DURING INCUBATION IN SOIL
When two different soils were incubated after the addition of [14C] glucose in the dark at winter temperatures or at 5°C in the laboratory and then hydrolysed, radioactivity was detected in all seven common soil sugars except arabinose. In contrast, in incubations at 20°C, little radioactivity was found in the xylose. Examination of the microflora showed that the number of viable bacteria was one-tenth at the lower temperatures, whereas the numbers of yeasts, fungi, and actinomycetes were unaffected. Analysis of cultures of representative microbial isolates showed that none of the fungi or actinomycetes and only 3 per cent of the bacteria synthesized xylose, compared with 85 per cent of the yeasts. It is concluded that when these soils are incubated at low temperatures xylose is synthesized principally by yeasts. 相似文献
17.
About one-quarter of 6- to 15-day old sugar cane (cv NA56-79) propagated from surface sterile or untreated single node cuttings in sterile vermiculite exhibited acetylene-reducing activity (ARA). Most of this ARA was in the rhizosphere vermiculite. There was no ARA before sprouting of the cuttings. There were numerous nitrogen-fixing and other bacteria in macerated untreated and macerated surface sterile cuttings, and nitrogen-fixers were enriched when small sections taken from internal tissues of cuttings were incubated on sucrose agar slants under air. Possible sites of N2-fixers in the stem tissues, and possible routes of movement of these bacteria into the rhizosphere after germination were indicated by observations of distributions of tetrazolium-reducing bacteria. There was no evidence of progressive invasion of the stem from the surface inwards. It is suggested that the most likely origin of bacteria in the stem is in the root interior where tetrazolium-reducing bacteria were observed in the same types of sites as in the stems, viz. in intercellular spaces and in the xylem. Reestablishment of the stem bacteria in the roots and rhizosphere soil following germination appears to constitute an instance of cyclic infection. This phenomenon may be of significance historically, and potentially, to perpetuate and enhance N2 fixation by sugar cane. 相似文献
18.
水稻田土壤甲烷氧化活性及其环境影响因子的研究 总被引：9，自引：0，他引：9
报道环境因子土壤含水量、温度和pH对发育于河流沉积物母质的水稻田土黄松泥田土氧化外源甲烷活性影响的研究结果。表明土壤中存在有氧和无氧两个甲烷氧化系统。有氧甲烷氧化系统 (AMOS)最适条件下的氧化甲烷最大活性比无氧甲烷氧化系统(AAMOS)最适条件下的氧化甲烷最大活性高 1至 2倍。在土壤通气良好的条件下 ,AMOS占主导地位 ,在无氧或极微氧的土壤中 ,AAMOS起主要作用。影响活性的主要因子是土壤的分子氧含量、甲烷含量、水含量、温度和pH值。分子氧对AAMOS氧化甲烷的活性具有一定抑制作用 ,土壤中甲烷量和含水量对AAMOS氧化甲烷活性的影响比对AMOS氧化甲烷活性的影响更为强烈。土壤氧化甲烷的活性对温度较为敏感 ,其最适氧化甲烷的温度范围在 2 5～ 35℃之间。当土壤在 5 0℃培养的时间超过 6h后 ,土壤氧化外源甲烷的活性全部丧失 ,且不能在2 8℃下得到恢复。pH是另一个影响土壤氧化甲烷的重要环境因子。其最适pH范围在 6～ 7之间 ,pH低于 3或pH高于 9时 ,几乎完全丧失氧化外源甲烷的活性。 相似文献
19.
I J Mehlman A Romero B A Wentz 《Journal of the Association of Official Analytical Chemists》1985,68(3):552-555
Shigella species were recovered from foods by the procedure described in the Bacteriological Analytical Manual, 5th Ed. The method is effective if Shigella species are present at about 10(6) cells/g. A 25 g food portion was incubated in Gram-negative (GN) and selenite cystine broths for 16 h at 35 degrees C and streaked onto MacConkey, Levine's eosin methylene blue, desoxycholate citrate, and xylose lysine desoxycholate agars. S. sonnei cells were recovered quantitatively at 44.5 degrees C, and along with other Shigella species, were grown with Escherichia coli in a tryptone broth under anaerobic conditions. Shigella species were also grown in a mixed microflora from foods. S. sonnei cells were inoculated into an enrichment broth containing 20 g tryptone, 2 g K2HPO4, 2 g KH2PO4, 1 g glucose, 5 g NaCl, 1.5 mL Tween 80, and 0.5 mg novobiocin/L (pH 7.0) and incubated for 20 h at 44 degrees C. Enrichments were streaked onto MacConkey agar and the plates were incubated 20 h at 35 degrees C. Suspect Shigella colonies were screened in glucose, tryptone, and lysine broths and in triple sugar iron and motility agars. The sensitivity varied from 0.3 to 1000 bacteria/g. The method has been examined with artificially inoculated lettuce, celery, brussels sprouts, mushrooms, and hamburger. It is also applicable to S. flexneri if incubation is conducted at 42 degrees C. 相似文献
20.
从石灰性土壤作物根际土样筛选出2株具有较强解P能力的优势菌株“B2”和“B67”,平板培养溶P圈D/d值分别为5.1和3·8,液体摇床培养过程中产生苹果酸、丙二酸、草酸和乳酸等多种有机酸,产酸总量分别为对照的28·25和19.78倍,pH分别较对照下降2.3和1.1,将“B2”和“B67”的培养液分别接种到4个不同地区土壤中恒温恒湿培养20d后测定结果表明,所有土壤中速效磷含量均有所提高,且接种“B2”处理分别为对照的2.64、3.04、1.71和2.20倍,接种“B67”处理分别为对照的2.12、1.90、1.35和1.78倍,且发现其溶P效果和土壤磷酸酶活性与有效活菌数变化趋势基本一致。 相似文献