共查询到20条相似文献,搜索用时 15 毫秒
1.
P. Alagu Sundaram Robin Augustine M. Kannan 《Biotechnology and Bioprocess Engineering》2012,17(4):835-840
The biological synthesis of nanoparticles is emerging as a potential method for nanoparticle synthesis due to its non-toxicity and simplicity. We report the ability of Bacillus subtilis strains isolated from rhizosphere soil to produce iron oxide nanoparticles. B. subtilis strains having the potential for the extracellular biosynthesis of Fe3O4nanoparticles were isolated from rhizosphere soil, identified and characterized. A bactericidal protein subtilin was isolated from all the isolates of B. subtilis, which is a characteristic for the species. The isolated subtilin was tested against the bacterial strain, E. coli. The supernatant of the bacterial culture was used for the synthesis of Fe3O4 nanoparticles. The formation of nanoparticles was assessed by using UV-Visible spectrophotometer. FTIR and SEM analysis were used in order to confirm the formation and size of the nanoparticles. Further, the effect of incubation time, pH, and temperature on the formation of Fe3O4 nanoparticles was studied. The successful synthesis of stabilized Fe3O4 nanoparticles, which was capped by the organic group, indicates the applicability of the isolated B. subtilis strain for the bulk synthesis of iron oxide nanoparticles. 相似文献
2.
Undine Behrendt Peter Schumann Michaela Stieglmeier Rüdiger Pukall Jürgen Augustin Cathrin Spröer Petra Schwendner Christine Moissl-Eichinger Andreas Ulrich 《Systematic and applied microbiology》2010
In the course of studying the influence of N-fertilization on N2 and N2O flux rates in relation to soil bacterial community composition of a long-term fertilization experiment in fen peat grassland, a strain group was isolated that was related to a strain isolated from a spacecraft assembly clean room during diversity studies of microorganisms, which withstood cleaning and bioburden reduction strategies. Both the fen soil isolates and the clean room strain revealed versatile physiological capacities in N-transformation processes by performing heterotrophic nitrification, respiratory ammonification and denitrification activity. 相似文献
3.
Hong Jiang Nan-Nan Liu Guang-Lei Liu Zhe Chi Jian-Ming Wang Ly-Ly Zhang Zhen-Ming Chi 《Extremophiles : life under extreme conditions》2016,20(4):567-577
The yeast strain XJ5-1 isolated from the Taklimakan desert soil was identified to be a strain of Aureobasdium melanogenum and could produce a large amount of melanin when it was grown in the PDA medium, but its melanin biosynthesis and expression of the PKS gene responsible for the melanin biosynthesis was significantly repressed in the presence of (NH4)2SO4. However, A. melanogenum P5 strain isolated from a mangrove ecosystem grown in both the presence and the absence of (NH4)2SO4 did not produce any melanin. The cell size of A. melanogenum XJ5-1 strain was much higher than that of A. melanogenum P5 strain. The melanized cells of the yeast strain XJ5-1 had higher tolerance to UV radiation, oxidation (200.0 mM H2O2), heat treatment (40 °C), salt shock (200.0 g/L NaCl), desiccation and strong acid hydrolysis (6.0 M HCl) at high temperature (80 °C) than the non-melanized cells of the same yeast strain XJ5-1. At the same time, the melanized cells of the yeast strain XJ5-1 also had higher tolerance to UV radiation, oxidation (200.0 mM H2O2), desiccation and strong acid hydrolysis (6.0 M HCl) at high temperature (80 °C) than A. melanogenum P5 strain, but had similar resistance to heat treatment (40 °C) and salt shock (200.0 g/L NaCl) compared to those of A. melanogenum P5 strain. All the results revealed that many characteristics of A. melanogenum XJ5-1 isolated from the Taklimakan desert soil was different from those of A. melanogenum P5 strain isolated from the mangrove ecosystem. 相似文献
4.
Free-Living Rhizobium Strain Able To Grow on N2 as the Sole Nitrogen Source 总被引:10,自引:2,他引:8
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A Rhizobium strain isolated from stem nodules of the legume Sesbania rostrata was shown to grow on atmospheric nitrogen (N2) as the sole nitrogen source. Non-N2-fixing mutants isolated directly on agar plates formed nodules that did not fix N2 when inoculated into the host plant. 相似文献
5.
Brachyspira (Serpulina) hyodysenteriae gyrB Mutants and Interstrain Transfer of Coumermycin A1 Resistance
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To further develop genetic techniques for the enteropathogen Brachyspira hyodysenteriae, the gyrB gene of this spirochete was isolated from a λZAPII library of strain B204 genomic DNA and sequenced. The putative protein encoded by this gene exhibited up to 55% amino acid sequence identity with GyrB proteins of various bacterial species, including other spirochetes. B. hyodysenteriae coumermycin A1-resistant (Cnr) mutant strains, both spontaneous and UV induced, were isolated by plating B204 cells onto Trypticase soy blood agar plates containing 0.5 μg of coumermycin A1/ml. The coumermycin A1 MICs were 25 to 100 μg/ml for the resistant strains and 0.1 to 0.25 μg/ml for strain B204. Four Cnr strains had single nucleotide changes in their gyrB genes, corresponding to GyrB amino acid changes of Gly78 to Ser (two strains), Gly78 to Cys, and Thr166 to Ala. When Cnr strain 435A (Gly78 to Ser) and Cmr Kmr strain SH (ΔflaA1::cat Δnox::kan) were cultured together in brain heart infusion broth containing 10% (vol/vol) heat-treated (56°C, 30 min) calf serum, cells resistant to chloramphenicol, coumermycin A1, and kanamycin could be isolated from the cocultures after overnight incubation, but such cells could not be isolated from monocultures of either strain. Seven Cnr Kmr Cmr strains were tested and were determined to have resistance genotypes of both strain 435A and strain SH. Cnr Kmr Cmr cells could not be isolated when antiserum to the bacteriophage-like agent VSH-1 was added to cocultures, and the numbers of resistant cells increased fivefold when mitomycin C, an inducer of VSH-1 production, was added. These results indicate that coumermycin resistance associated with a gyrB mutation is a useful selection marker for monitoring gene exchange between B. hyodysenteriae cells. Gene transfer readily occurs between B. hyodysenteriae cells in broth culture, a finding with practical importance. VSH-1 is the likely mechanism for gene transfer. 相似文献
6.
A noncrystalliferous, aerobic, spore-forming bacterium (accession number DD-1019) isolated from the cigarette beetle, Lasioderma serricorne, was identified as a strain of Bacillus cereus based on morphological, biochemical, and cultural similarities. Pathogenicity was established by exposing hatching larvae of the cigarette beetle to doses of inocula ranging from 1.17 to 600 × 106 spores per gram of rearing medium. The LD50 and the LD90 were calculated to be 4.29 × 106 and 371 × 106 spores per gram of medium, respectively. The cigarette beetle was effectively controlled by both the DD-1019 strain of B. cereus and the CM1-1 strain (originally isolated from and pathogenic to codling moth, Laspeyresia pomonella) but proved quite refractory to Bacillus thuringiensis var. thuringiensis. 相似文献
7.
《Journal of Fermentation and Bioengineering》1993,75(3):182-186
We isolated about 500 isopropanol(IPA)-assimilating bacteria from many soil samples, among which 23 strains produced vitamin B12. Taxonomical studies of the best producer, designated strain Hi16.3, showed that it belonged to the genus Arthrobacter. Vitamin B12 production by the strain was higher than that by 12 other authentic Arthrobacter spp. using glucose as a sole carbon source. In fed-batch culture, the maximum production yield with strain Hi16.3 (named A. hyalinus) was 2 mg/l in the culture broth, when 80 ml of IPA/l broth was consumed. 相似文献
8.
A New Chloroplast Protein Is Induced by Growth on Low CO(2) in Chlamydomonas reinhardtii 总被引:3,自引:3,他引:0
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The biosynthesis of a 36 kilodalton polypeptide of Chlamydomonas reinhardtii was induced by photoautotrophic growth on low CO2. Fractionation studies using the cell-wall-deficient strain of C. reinhardtii, CC-400, showed that this polypeptide was different from the low CO2-induced periplasmic carbonic anhydrase. In addition, the 36 kilodalton polypeptide was found to be localized in intact chloroplasts isolated from low CO2-adapting cultures. This protein may, in part, account for the different inorganic carbon uptake characteristics observed in chloroplasts isolated from high and low CO2-grown C. reinhardtii cells. 相似文献
9.
Arnaud Ducruix Nestor Hounwanou Joseph Reinbolt Yves Boulanger Sylvain Blanquet 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1983,741(2):244-250
Phenylalanyl-tRNA synthetase (EC 6.1.1.20) has been purified to homogeneity from a 100-fold overproducing Escherichia coli strain carrying a hybrid pBR322 plasmid containing the pheS-pheT locus. The purified enzyme is identical to the phenylalanyl-tRNA synthetase isolated from an haploid strain. The enzyme was found to dissociate in the presence of 0.5 M NaSCN and the α- and β-subunits composing the native α2β2 enzyme were separated by gel filtration. Neither isolated subunit showed significant catalytic activity. A complex indistinguishable from the native enzyme with full catalytic activity is recovered upon mixing the subunits. The N- and C-terminal sequences and the amino acid composition of each subunit were determined. They are compared to the available data concerning the primary structure of the subunits, as deduced from nucleotide sequencing of the pheS-pheT operon. 相似文献
10.
An extrinsic substance (ES-6000) was isolated from the periplasmic space of Rhizobium trifolii (strain 4S) cells by osmotic shock, using a high-density sucrose solution. This substance promoted infection thread formation in root hairs of white clover when inoculated together with the infectious strain (4S). However, ES-6000 obtained from another rhizobial species and from strain A1, which is a noninfectious mutant strain obtained from strain 4S, did not have this effect. The promoter in the ES-6000 from strain 4S is a relatively small molecule since it passed through a hollow-fiber membrane (molecular weight, 6,000). This substance was also recognized as an Rf 0.1 fraction by paper chromatography. Sucrose was effective in promoting nodulation and root elongation. 相似文献
11.
Properties of the Photosynthetic System and DNA of Cyanophora paradoxa Cyanelles 总被引:1,自引:1,他引:0
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The cyanelle from the photosynthetic biflagellate protist Cyanophora paradoxa has been studied in terms of its photosynthetic properties. Structurally, the cyanelle resembles unicellular cyanobacteria. The cyanelle is readily released from the host cell by means of the French press. The isolated cyanelle shows typical photosystem I and photosystem II activities as well as phenazine methosulfate-mediated photophosphorylation. The kinetic parameters Km and Vmax were determined for CO2 fixation in the cyanelle and cells of C. paradoxa and compared to a cyanobacterium. The determined values were not much different, although the cyanobacterium had a significantly greater rate of CO2 fixation, and the cyanelle was least active in this regard. Photosystem I chlorophyll-protein complex is readily isolated from the thylakoid membrane. In all these respects, the photosynthetic apparatus of the cyanelle resembles that of cyanobacteria. No nitrogen fixation activity was observed. Attempts to regenerate the isolated cyanelle were not successful, but in some cases, an unidentified cyanobacterium grew up in standing cultures of C. paradoxa cyanelles. Buoyant density data indicate that the strain of C. paradoxa we have investigated differs from that employed by others, since our strain shows a value of 1.716 grams per cubic centimeter and others report values of 1.695 and 1.691. 相似文献
12.
B. Sudha Kalyani P.S. Krishna K. Sreenivasulu 《Saudi Journal of Biological Sciences》2019,26(7):1655-1660
Actinobacteria, which are the prolific producers of antibiotics and significant suppliers to the pharmaceutical industry, can produce a wide variety of bioactive metabolites. An actinomycete strain designated NLKPB45 was isolated from mangrove soils samples of Nellore coastal regions Andhra Pradesh and assessed for antibiotic production and activity against pathogenic bacteria. From a total of 9 mangrove soil samples, 143 acinomycetes were isolated. Among the isolated them 6 actinomycetes strains showed potential antibacterial activity against at two tested pathogens gram positive and gram negative bacteria E. coli and S. aureus. The potent strain NLKPB45 was identified by 16S gene isolation and sequencing to the Streptomyces genus. The ethyl acetate extracts also as shown excellent antimicrobial activity against Salmonella sp., staphylococcus aureus, E. coli, and B. subtilus were detected in both the supernatant extract samples from fermentations of culture NLKPB45. The anticancer activity of extracts in the HeLa with IC50 value of 37.1924 μg/ml, MCF-7 IC50 value of 40.9177 μg/ml and HT 29 IC50 value of 43.3758 μg/ml. 相似文献
13.
Growth of Desulfovibrio in Lactate or Ethanol Media Low in Sulfate in Association with H2-Utilizing Methanogenic Bacteria 总被引:37,自引:29,他引:8
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In the analysis of an ethanol-CO2 enrichment of bacteria from an anaerobic sewage digestor, a strain tentatively identified as Desulfovibrio vulgaris and an H2-utilizing methanogen resembling Methanobacterium formicicum were isolated, and they were shown to represent a synergistic association of two bacterial species similar to that previously found between S organism and Methanobacterium strain MOH isolated from Methanobacillus omelianskii. In lowsulfate media, the desulfovibrio produced acetate and H2 from ethanol and acetate, H2, and, presumably, CO2 from lactate; but growth was slight and little of the energy source was catabolized unless the organism was combined with an H2-utilizing methanogenic bacterium. The type strains of D. vulgaris and Desulfovibrio desulfuricans carried out the same type of synergistic growth with methanogens. In mixtures of desulfovibrio and strain MOH growing on ethanol, lactate, or pyruvate, diminution of methane produced was stoichiometric with the moles of sulfate added, and the desulfovibrios grew better with sulfate addition. The energetics of the synergistic associations and of the competition between the methanogenic system and sulfate-reducing system as sinks for electrons generated in the oxidation of organic materials such as ethanol, lactate, and acetate are discussed. It is suggested that lack of availability of H2 for growth of methanogens is a major factor in suppression of methanogenesis by sulfate in natural ecosystems. The results with these known mixtures of bacteria suggest that hydrogenase-forming, sulfate-reducing bacteria could be active in some methanogenic ecosystems that are low in sulfate. 相似文献
14.
An oxygen sensitive mutant of Azorhizobium caulinodans strain IRBG 46 was isolated by NTG mutagenesis. It was defective in N2 fixation under 3% O2 level, while under 1% O2 it was almost as active as the parent strain IRBG 46. The mutant was also found to be a slow grower with reduced respiratory activity, low azide tolerance and no catalase activity. However, it did not differ from its parent strain with respect to nitrate respiration. Under symbiotic condition the mutant formed smaller, light green nodules as compared to bigger, dark green nodules formed by the wild type strain. The mutant was also defective in N2 fixation under symbiotic condition. Complementation analysis showed that the mutation might be in either fixL or fixJ gene which are involved in O2 regulation of nif/fix gene expression. A possible role of all these factors in conferring a highly O2 tolerant nitrogen fixing system in the organism, has been discussed. 相似文献
15.
《Journal of Fermentation and Bioengineering》1991,71(1):44-49
Thiobacillus sp. HA43 as a dominant strain was isolated from a H2S-acclimated peat biofilter seeded with aerobically-digested sludge of night soil. Strain IIA43 degraded both H2S and methanethiol (MT) without lag-time, but degraded neither dimethy sulphide (DMS) nor dimethyl disulphide (DMDS). The removal characteristics for sulphur compounds (H2S, MT, DMS and DMDS) by strain HA43 well reflected the removal behaviour of the H2S-acclimated peat biofilter where this strain was isolated. The specific H2S and MT uptake rates of strain HA43 in batch culture were determined as 1.22 × 10−12 and 8.53 × 10−14 g-S·cell−1·h−1, respectively. The maximum removal rates (Vm = g-S·kg-dry peat−1·d−1) for H2S and MT by peat biofilter inoculated by strain HA43 were obtained as follows: Vm(H2S)− 11.3, Vm(MT) = 0.21 in sterilized peat; Vm(H2S) = 12.4, Vm(MT)− 0.27 in non-sterilized peat; Vm(H2S) = 33.0, Vm(MT) = 0.27 in peat with aerobically-digested sludge of night soil. The peat biofilter inoculated with strain HA43 enhanced the maximum removal rate for H2S 6-fold compared with the biofilter without strain HA43. 相似文献
16.
《Journal of Fermentation and Bioengineering》1992,73(1):76-78
A strictly anaerobic, homoacetogenic bacterium strain 69, which produces high amounts of intracellular vitamin B12, was isolated from sea sediment. Taxonomical and physiological studies revealed that the isolate should be classified in the genus Acetobacterium. The isolate grown on methanol produced ca. 11 mg of cyanocobalamin per gram dry cells after 7-d cultivation. Tetrachloromethane (TCM) resistant mutants, strain 67-7 and 69-23, were obtained from the isolate by ethylmethanesulfonate treatment, and produced ca. 23 mg of cyanocobalamin per gram dry cells for strain 69-7 and 20 mg for strain 69-23 in the presence of 10 μM of TCM. 相似文献
17.
Shinobu Isshiki Sachiyo Shitasue Tamio Mase Tetsuya Kondo Shouko Kamino Yuka Kamei 《Mycoscience》2017,58(1):60-67
Yeast strain 31-B was isolated from the digestive juices of Nepenthes alata as an aminopeptidase producer and identified as Pseudozyma hubeiensis via morphological testing and comparative 26S ribosomal DNA-D1/D2 gene sequence analysis. Strain 31-B produced aminopeptidase as extracellular peptidase, but proteinase activity was not detected in the culture filtrate. The aminopeptidase from strain 31-B was purified from filtered culture medium by (NH4)2SO4 precipitation and four column chromatography steps: Diethylaminoethyl (DEAE)-Toyopearl 650 M, Butyl-Toyopearl 650 M, hydroxylapatite, and Toyopearl HW-55. Sodium dodecyl sulfate polyacrylamide gel electrophoresis yielded the purified enzyme as a single band with molecular mass 75.3 kDa. The optimum temperature and pH were approximately 40 °C and 8.0, respectively. The purified aminopeptidase preferentially hydrolyzed Leu-p-NA and its activity was inhibited by ethylenediaminetetraacetic acid. The isolated aminopeptidase reduced the bitterness of peptides generated from milk casein using a bacterial proteinase. These results show that the aminopeptidase produced by P. hubeiensis 31-B has potential application as a food additive in the dairy industry. 相似文献
18.
Ferretti G., Gabriele F. and Palmas C. 1981. Development of human and mouse strain of Hymenolepis nana in mice. International Journal for Parasitology11: 425–430. An Hymenolepis nana strain isolated from human faeces was transferred in the mouse. At first, the q ratio (the number of parasites to the number of eggs used) was very low. After 10 passages adaptation was complete: when mice of different age and strain (CD1 and BDF1) were infected with eggs of the above strain and eggs of 2 different murine strains, no differences emerged in the q ratio or in the parasite mean dry weight. Survival also appeared the same in the 3 parasite strains, however, human and murine strains live for a shorter time in BDF1 than in CD1 mice. Discussion bears on the hypothesis that the difficulties that emerge during the first passages may be connected to the adult and not to the larval phase. 相似文献
19.
Cédric Tarayre Alison Brognaux Julien Bauwens Catherine Brasseur Christel Mattéotti Catherine Millet Jacqueline Destain Micheline Vandenbol Daniel Portetelle Edwin De Pauw Haubruge Eric Frédéric Francis Philippe Thonart 《World journal of microbiology & biotechnology》2014,30(5):1655-1660
The aim of this work was to isolate enzyme-producing microorganisms from the tract of the termite Reticulitermes santonensis. The microorganisms were extracted from the guts and anaerobic (CO2 or CO2/H2) and micro-aerobic atmospheres were used to stimulate growth. Three different strategies were tried out. First, the sample was spread on Petri dishes containing solid media with carboxymethylcellulose, microcrystalline cellulose or cellobiose. This technique allowed us to isolate two bacteria: Streptomyces sp. strain ABGxAviA1 and Pseudomonas sp. strain ABGxCellA. The second strategy consisted in inoculating a specific liquid medium containing carboxymethylcellulose, microcrystalline cellulose, or cellobiose. The samples were then spread on Petri dishes with the same specific medium containing carboxymethylcellulose, microcrystalline cellulose, or cellobiose. This led to the isolation of the mold Aspergillus sp. strain ABGxAviA2. Finally, the third strategy consisted in heating the first culture and spreading samples on agar plates containing rich medium. This led to the isolation of the bacterium Bacillus subtilis strain ABGx. All those steps were achieved in controlled atmospheres. The four enzyme-producing strains which were isolated were obtained by using a micro-aerobic atmosphere. Later, enzymatic assays were performed on the four strains. Streptomyces sp. strain ABGxAviA1 was found to produce only amylase, while Pseudomonas sp. strain ABGxCellA was found to produce β-glucosidase as well. Aspergillus sp. strain ABGxAviA2 showed β-glucosidase, amylase, cellulase, and xylanase activities. Finally, B. subtilis strain ABGx produced xylanase and amylase. 相似文献
20.
A.E. Galván M.C. Chalón L.A. Schurig-Briccio R.A. Salomón C.J. Minahk R.B. Gennis A. Bellomio 《BBA》2018,1859(2):110-118
Microcin J25 has two targets in sensitive bacteria, the RNA polymerase, and the respiratory chain through inhibition of cellular respiration. In this work, the effect of microcin J25 in E. coli mutants that lack the terminal oxidases cytochrome bd-I and cytochrome bo3 was analyzed. The mutant strains lacking cytochrome bo3 or cytochrome bd-I were less sensitive to the peptide. In membranes obtained from the strain that only expresses cytochrome bd-I a great ROS overproduction was observed in the presence of microcin J25. Nevertheless, the oxygen consumption was less inhibited in this strain, probably because the oxygen is partially reduced to superoxide. There was no overproduction of ROS in membranes isolated from the mutant strain that only express cytochrome bo3 and the inhibition of the cellular respiration was similar to the wild type. It is concluded that both cytochromes bd-I and bo3 are affected by the peptide. The results establish for the first time a relationship between the terminal oxygen reductases and the mechanism of action of microcin J25. 相似文献