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1.
Isolations from oak symptomatic of Acute Oak Decline, alder and walnut log tissue, and buprestid beetles in 2009–2012 yielded 32 Gram-negative bacterial strains showing highest gyrB sequence similarity to Rahnella aquatilis and Ewingella americana. Multilocus sequence analysis (using partial gyrB, rpoB, infB and atpD gene sequences) delineated the strains into six MLSA groups. Two MLSA groups contained reference strains of Rahnella genomospecies 2 and 3, three groups clustered within the Rahnella clade with no known type or reference strains and the last group contained the type strain of E. americana. DNA–DNA relatedness assays using both the microplate and fluorometric methods, confirmed that each of the five Rahnella MLSA groups formed separate taxa. Rahnella genomospecies 2 and 3 were previously not formally described due to a lack of distinguishing phenotypic characteristics. In the present study, all five Rahnella MLSA groups were phenotypically differentiated from each other and from R. aquatilis. Therefore we propose to classify the strains from symptomatic oak, alder and walnut and buprestid beetles as: Rahnella victoriana sp. nov. (type strain FRB 225T = LMG 27717T = DSM 27397T), Rahnella variigena sp. nov. (previously Rahnella genomosp. 2, type strain CIP 105588T = LMG 27711T), Rahnella inusitata sp. nov. (previously Rahnella genomosp. 3, type strain DSM 30078T = LMG 2640T), Rahnella bruchi sp. nov. (type strain FRB 226T = LMG 27718T = DSM 27398T) and Rahnella woolbedingensis sp. nov. (type strain FRB 227T = LMG 27719T = DSM 27399T).  相似文献   

2.
This research was initiated to search for novel antimicrobial compounds produced by food or environmental microorganisms. A new bacterial strain, designated OSY-SE, which produces a unique and potent antimicrobial agent was isolated from soil. The isolate was identified as a Paenibacillus sp. through cultural, biochemical, and genetic analyses. An antimicrobial compound was extracted from Paenibacillus OSY-SE with acetonitrile and purified using liquid chromatography. After analyses by mass spectrometry (MS) and nuclear magnetic resonance (NMR), the antimicrobial compound was determined to be a cyclic lipopeptide consisting of a C(15) fatty acyl (FA) chain and 13 amino acids. The deduced sequence is FA-Orn-Val-Thr-Orn-Ser-Val-Lys-Ser-Ile-Pro-Val-Lys-Ile. The carboxyl-terminal Ile is connected to Thr by ester linkage. The new compound, designated paenibacterin, showed antagonistic activities against most Gram-positive and Gram-negative bacteria tested, including Listeria monocytogenes, methicillin-resistant Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella enterica serovar Typhimurium. Paenibacterin is resistant to trypsin, lipase, α-glucosidase, and lysozyme. Its antimicrobial activity was lost after digestion by pronase and polymyxin acylase. Paenibacterin is readily soluble in water and fairly stable to exposure to heat and a wide range of pH values. The new isolate and its antimicrobial agent are being investigated for usefulness in food and medical applications.  相似文献   

3.
Rahnella sp. strain Y9602 is a gammaproteobacterium isolated from contaminated subsurface soils that is capable of promoting uranium phosphate mineralization as a result of constitutive phosphatase activity. Here we report the first complete genome sequence of an isolate belonging to the genus Rahnella.  相似文献   

4.
A strain of bacterium producing antifungal antibiotic was isolated and identification of the strain was attempted. We could identify the bacterium as being a Bacillus sp., based on morphological observation, physiological characteristics, and 16S rDNA sequence analysis, thus leading us to designate the strain as Bacillus sp. AH-E-1. The strain showed potent antibiotic activity against phytopathogenic and human pathogenic fungi by inducing mycelial distortion and swelling and inhibiting spore germination. The antibiotic metabolite produced by the strain demonstrated excellent thermal and pH (2-11) stability, but was labile to autoclaving. From these results, we could find a broader antifungal activity of Bacillus genus. Isolation and characterization of the active agent produced by the strain are under progress.  相似文献   

5.
Biodegradation of petroleum compounds in saline environments seems intricate and needs more attention. In this study, tetracosane was used to enrich alkane-degrading bacteria from oil-contaminated saline soils. Among the isolates, strain Qtet3, with the highest 16s rRNA gene sequence similarity to Alcanivorax dieselolei B-5T, was able to grow at a wide range of NaCl concentrations and was shown by GC analysis to degrade more than 90% of tetracosane in 10 days. This strain has at least two alkB genes and could grow on crude oil and diesel fuel, and utilize various pure aliphatic hydrocarbon substrates (from C12 to C34). Highly hydrophobic cell surfaces and lack of significant surface tension reduction in the media suggest that the main mechanism of the cells for accessing substrate is to attach directly to hydrocarbon particles. Application of this strain for remediating crude oil-contaminated soils irrigated with defined saline water demonstrated that this halotolerant bacterium could survive and grow in saline soils irrigated with NaCl solutions up to 5% w/v, with the highest hydrocarbon degradation of 26.1% observed at 2.5% NaCl. This strain is promising for future industrial applications especially in bioremediation of saline soils and wastes.  相似文献   

6.
Plant and Soil - The aims of this work were (i) to find a soil indicator to predict durum wheat yield response to Zn fertilization, (ii) to compare the effect of various Zn fertilization strategies...  相似文献   

7.
产低温脂肪酶菌株Psychrobacter sp.7342的筛选及粗酶性质研究   总被引:1,自引:0,他引:1  
从南北极环境土样中筛选到1株产脂肪酶细菌7342,16SrDNA序列分析表明该菌株属于Psychrobacter sp..p-NPP法研究显示,菌株7342所产粗酶液的最适温度为30℃、最适pH值为8.0,对热较稳定;Co2+和Cs+对粗酶液有激活作用,而Na+、Sr2+等7种金属离子对其均有不同程度的抑制作用;粗酶液能在高浓度的SDS、Tween20等变性剂中表现出较好的稳定性.  相似文献   

8.
Volatile and nonvolatile compounds emitted from the plant growth-promoting rhizobacterium Bacillus sp. strain JS enhance the growth of tobacco and lettuce. Here, we report the high-quality genome sequence of this bacterium. Its 4.1-Mb genome reveals a number of genes whose products are possibly involved in promotion of plant growth or antibiosis.  相似文献   

9.
Photosynthetic, nitrogen-fixing Anabaena strains are native to tropical paddy fields and contribute to the carbon and nitrogen economy of such soils. Genetic engineering was employed to improve the nitrogen biofertilizer potential of Anabaena sp. strain PCC7120. Constitutive enhanced expression of an additional integrated copy of the hetR gene from a light-inducible promoter elevated HetR protein expression and enhanced functional heterocyst frequency in the recombinant strain. The recombinant strain displayed consistently higher nitrogenase activity than the wild-type strain and appeared to be in homeostasis with compatible modulation of photosynthesis and respiration. The enhanced combined nitrogen availability from the recombinant strain positively catered to the nitrogen demand of rice seedlings in short-term hydroponic experiments and supported better growth. The engineered strain is stable, eco-friendly, and useful for environmental application as nitrogen biofertilizer in paddy fields.  相似文献   

10.
Citrobacter sp. strain KCTC 18061P was found to be able to decolorize textile plant effluent containing different types of reactive dyes. Effects of physico-chemical parameters, such as aeration, nitrogen source, glucose and effluent concentrations on the color removal of real dye effluent by this strain were investigated. The observed changes in the visible spectra indicated color removal by the absorption of dye to cells during incubation with the strain. This strain showed higher decolorization ability under aerobic than static culture conditions. With 1% glucose, this strain removed 70% of effluent color within 5 days. Decolorization was not significantly dependent on the nitrogen sources tested. Chemical oxygen demand (COD) and biological oxygen demand (BOD) were decreased in proportion to incubation times, and their removal rates were about 35% and 50%, respectively, at 7 days of culture.  相似文献   

11.
石灰性土壤拉恩式溶磷细菌的筛选鉴定及溶磷特性   总被引:3,自引:0,他引:3  
从山西石灰性土壤作物根际分离筛选出多株溶磷细菌,经过多次分离纯化得到一株溶磷能力较强的菌株W25,通过菌落形态、生理生化特性和16S rRNA序列分析,确定溶磷菌W25为拉恩式菌属.对W25溶解磷特性进一步研究表明:其对磷酸三钙、磷酸铝和磷酸铁最高溶磷能力分别为385.5、110.4、216.6 mg·L-1;在磷酸铝和磷酸铁培养液中,W25溶磷量与培养液pH的相关系数分别为0.56和0.81,呈极显著负相关;在不同碳氮源条件下,W25以葡萄糖为碳源和NH4NO3为氮源时对磷酸三钙的溶磷量最高,对碳源的利用顺序依次为葡萄糖>乳糖>蔗糖>甘露醇>淀粉,对氮源的利用顺序依次为NH4NO3 >NH4Cl>(NH4)2SO4>NaNO3>KNO3.不同氮源对W25产生有机酸的种类影响较大,以铵态氮为氮源产生甲酸和乙酸,以硝态氮为氮源产生草酸和琥珀酸,以硝酸铵为氮源还产生柠檬酸.  相似文献   

12.
拉恩氏菌W25对缓冲容量的响应及其产酸特性   总被引:1,自引:0,他引:1  
【目的】进一步了解拉恩氏菌W25的溶磷机理和对土壤缓冲容量的响应。【方法】在液体摇瓶培养过程中,采用调节培养液pH的方法研究模拟土壤的缓冲容量对拉恩氏菌W25溶磷量的影响;通过单因子试验和HPLC相结合的方法,研究不同碳源、磷源条件下W25的溶磷能力及产酸特性。【结果】拉恩氏菌W25在磷酸三钙培养液中培养120 h后有效磷含量达到最大值,培养液有效磷含量与培养液pH变化之间呈极显著负相关性(P<0.01);W25在培养第48?96 h具有较强的缓冲能力,培养液有效磷含量加碱处理与未加碱处理差异不显著(P<0.05),从第120 h开始,缓冲能力开始减弱,在168 h后基本丧失了缓冲能力;W25在不同碳源条件下溶磷能力差异显著(P<0.05),依次为葡萄糖>乳糖>蔗糖>甘露醇>淀粉,不同磷源中培养液有效磷含量差异极显著(P<0.01),依次为磷酸三钙>磷酸铁>磷酸铝>磷矿粉;不同碳源、磷源条件下W25培养液中有机酸的种类和浓度差异较大,W25溶磷能力的大小不仅与产酸的种类有关,而且也与产酸的浓度有关。【结论】研究结果为更深入研究拉恩氏菌溶磷机理提供条件,为拉恩氏菌的应用提供理论基础。  相似文献   

13.
The isolate NJ-101 obtained from agricultural soil was characterized and presumptively identified as Pseudomonas sp. The isolate exhibited efficient degradation of the insecticide carbofuran with a rate constant of 0.035 day(-1), following first-order rate kinetics. The ability of performing multifarious biological activities in tandem suggested the uniqueness of isolate NJ-101. The ability to produce hydrogen cyanide and siderophore stipulated its role in biological control. Furthermore, the growth inhibition of Fusarium sp. validated the antagonistic activity of NJ-101 against the common phytopathogens. Concurrent production of indole acetic acid, and solubilization of inorganic phosphate revealed its plant growth promoting potential. Thus, the innate capability of this novel isolate for parallel biodegradation, biocontrol and plant growth promotion has significance in management of the agro-environmental and phytopathological problems.  相似文献   

14.
A new actinobacterium strain, designated 2AT, was isolated from a soil sample collected from Guru Nanak Dev University, Punjab (India) and characterized using a polyphasic taxonomic approach. It showed antimicrobial activity against various Gram-positive and Gram-negative bacteria including drug resistant bacteria and fungi. The strain had chemotaxononomic and morphological properties typical of the genus Streptomyces. The 16S rRNA gene sequence of the strain showed 99.9, 99.5 and 99.5 % similarity with Streptomyces flavotricini DSM 40152T, Streptomyces toxytricini DSM 40178T and Streptomyces globosus DSM 40815T, respectively. This strain formed a coherent cluster with them and shared DNA–DNA homology of 37.6 ± 0.6, 34.4 ± 0.5 and 33.1 ± 0.4 % with type strains, S. flavotricini DSM 40152T, S. globosus DSM 40815T and S. toxytricini DSM 40178T, respectively. Further, the strain was readily distinguished from the phylogenetic close relatives in a variety of morphological, physiological and biochemical properties. Based on the genotypic and phenotypic characteristics, it is proposed that strain 2AT represents a novel species in the genus Streptomyces, for which the name Streptomyces amritsarensis sp. nov. is proposed, with the type strain 2AT (=MTCC 11845T=JCM 19660T).  相似文献   

15.

Aims

The main goal of the study reported herein was to assess the nodulation performance of a Mesorhizobium strain transformed with an exogenous ACC deaminase gene (acdS), and its subsequent ability to increase chickpea plant growth under normal and waterlogged conditions.

Methods

The Mesorhizobium ciceri strain LMS-1 was transformed with the acdS gene of Pseudomonas putida UW4 by triparental conjugation using plasmid pRKACC. A plant growth assay was conducted to verify the plant growth promotion ability of the LMS-1 (pRKACC) transformed strain under normal and waterlogging conditions. Bacterial ACC deaminase and nitrogenase activity was measured.

Results

By expressing the exogenous acdS gene, the transformed strain LMS-1 showed a 127% increased ability to nodulate chickpea and a 125% promotion of the growth of chickpea compared to the wild-type strain, under normal conditions. Plants inoculated with the LMS-1 wild-type strain showed a higher nodule number under waterlogging stress than under control conditions, suggesting that waterlogging increases nodulation in chickpea. No significant relationship was found between ACC deaminase and nitrogenase activity.

Conclusions

The results obtained in this study show that the use of rhizobial strains with improved ACC deaminase activity might be very important for developing microbial inocula for agricultural purposes.  相似文献   

16.
We announce the availability of a high-quality draft of the genome sequence of Amycolatopsis sp. strain 39116, one of few bacterial species that are known to consume the lignin component of plant biomass. This genome sequence will further ongoing efforts to use microorganisms for the conversion of plant biomass into fuels and high-value chemicals.  相似文献   

17.
Ma M  Wang C  Ding Y  Li L  Shen D  Jiang X  Guan D  Cao F  Chen H  Feng R  Wang X  Ge Y  Yao L  Bing X  Yang X  Li J  Du B 《Journal of bacteriology》2011,193(1):311-312
Paenibacillus polymyxa SC2 is an important plant growth-promoting rhizobacterium (PGPR). Here, we report the complete genome sequence of P. polymyxa SC2. Multiple sets of functional genes have been found in the genome. As far as we know, this is the first complete genome sequence of Paenibacillus polymyxa.  相似文献   

18.
Herbaspirillum sp. strain GW103 was isolated from rhizosphere soil of the reed Phragmites australis on reclaimed land. Here we report the 5.05-Mb draft genome sequence of the strain, providing bioinformation about the agronomic benefits of this strain, such as multiple traits relevant to plant root colonization and plant growth promotion.  相似文献   

19.
Methylophaga sp. strains JAM1 and JAM7 have been isolated from a denitrification system. Strain JAM1 was the first Methylophaga strain reported to be able to grow under denitrifying conditions. Here, we report the complete genome sequences of the two strains, which allowed prediction of gene clusters involved in denitrification in strain JAM1.  相似文献   

20.
Patterns of colonization of Vitis vinifera L. cv. Chardonnay plantlets by a plant growth-promoting bacterium, Burkholderia sp. strain PsJN, were studied under gnotobiotic conditions. Wild-type strain PsJN and genetically engineered derivatives of this strain tagged with gfp (PsJN::gfp2x) or gusA (PsJN::gusA11) genes were used to enumerate and visualize tissue colonization. The rhizospheres of 4- to 5-week-old plantlets with five developed leaves were inoculated with bacterial suspensions. Epiphytic and endophytic colonization patterns were then monitored by dilution plating assays and microscopic observation of organ sections. Bacteria were chronologically detected first on root surfaces, then in root internal tissues, and finally in the fifth internode and the tissues of the fifth leaf. Analysis of the PsJN colonization patterns showed that this strain colonizes grapevine root surfaces, as well as cell walls and the whole surface of some rhizodermal cells. Cells were also abundant at lateral root emergence sites and root tips. Furthermore, cell wall-degrading endoglucanase and endopolygalacturonase secreted by PsJN explained how the bacterium gains entry into root internal tissues. Host defense reactions were observed in the exodermis and in several cortical cell layers. Bacteria were not observed on stem and leaf surfaces but were found in xylem vessels of the fifth internode and the fifth leaf of plantlets. Moreover, bacteria were more abundant in the fifth leaf than in the fifth internode and were found in substomatal chambers. Thus, it seems that Burkholderia sp. strain PsJN induces a local host defense reaction and systemically spreads to aerial parts through the transpiration stream.  相似文献   

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