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1.
A bacterium isolated as resistant to alkyldimethylbenzylammonium chloride (benzalkonium chloride, BC) and tentatively identified as Enterobacter cloacae, was induced by BC to produce acidic polysaccharide. The optimum concentration of BC for production of the polysaccharide was 0.1% and the polysaccharide produced amounted to 1.0-2.0 mg per ml of culture broth. The best carbon and nitrogen sources for the polysaccharide production were glycerol and polypeptone.

The acidic polysaccharide was consisted of fucose, galactose, glucose, glucuronic acid, pyruvate, and acetate, like colanic acid. The production of the acidic polysaccharide was not induced by the addition of trimethylbenzylammonium chloride and tetramethylammonium chloride, but it was induced by p-fluorophenylalanine, and the results are discussed.  相似文献   

2.
Pseudomonas putida 10.2, a 3-chlorobenzoate (3CBa)-degrading bacterium, was isolated from a soil sample obtained from an agricultural area in Chiang Mai, Thailand. This bacterium could degrade 2mm 3CBa very rapidly with the concomitant formation of chloride ion when grown in mineral salt-yeast extract medium. The presence of glucose, lactose and pyruvate in the medium reduced the capability of this bacterium to degrade 3CBa. Metabolites such as 3-chlorocatechol (3CC), catechol and cis,cis-muconic acid (muconate) could be detected in the growth medium or in cell suspensions when 3CBa was used as the substrate. Furthermore, when crude enzyme extract prepared from 3CBa-grown P. putida 10.2 was incubated with 3CC, catechol and muconate could be detected in the reaction mixtures. Thus, the biodegradation pathway of 3CBa by P. putida 10.2 was proposed to involve transformation of 3CBa to 3CC. The dehalogenation step is believed to involve removal of chloride from 3CC to form catechol, which is subsequently converted to muconate.  相似文献   

3.
The bacterium, which was isolated from soil and identified as Enterobacter sp., was induced by hexachlorophen (HCP) and chlorhexidine (CH), as well as benzalkonium chloride (BC), to produce acidic polysaccharide. HCP is a bisphenol and CH is a bisbiguanido, while BC is a quarternary ammonium compound. The cells produced the maximum amount of the polysaccharide (0.3 ~ 0.9 mg as total sugar/mg dry weight cells) in a 0.07m potassium phosphate buffer (pH 7.2) containing 0.22 m glucose and approximately 0.1 mm BC or HCP, or 0.06 mm CH. There was no growth of the cells in these conditions. The polysaccharides produced in the presence of each drug were all composed of fucose, glucose, galactose and glucuronic acid. At the optimum concentration for polysaccharide production, a large amount of UV-absorbing material was released from the cells.  相似文献   

4.
The objective of this study was to evaluate the influence of seawater salts, and more specially sodium chloride, on the recovery ofEscherichia coli cells after exposure to natural seawater in laboratory microcosms, and the possible adaptation in this bacterium to high salinity. The recovery efficiency of a complex organic medium supplemented with sodium chloride largely depended on the strain and varied with starvation time and salinity. Moreover, cells previously grown on salted medium appeared more able to survive after exposure to seawater. It is assumed that, withinE. coli populations, some cells are able to adapt to seawater in the presence of both salts and organic matter.  相似文献   

5.
The labeling of red blood cells with technetium-99m(99mTc) depends on a reducing agent and stannous ions, as chloride or fluoride, are widely utilized. This labeling may also be altered by drugs. Moreover, some authors have reported that the survival of Escherichia coli (E. coli) cultures decreases in presence of stannous ions. Phytic acid is present in the daily diet and we evaluated its influence on: (i) the labeling of blood elements with 99mTc and (ii) on the survival of an E. coli strain treated with stannous fluoride. Heparinized whole blood was withdrawn from Wistar rats and it was incubated with stannous chloride and with 99mTc, as sodium pertechnetate, centrifuged and plasma (P) and blood cells (BC) were isolated. Samples of P and BC were also precipitaded with trichloroacetic acid, centrifuged and soluble (SF) and insoluble fractions (IF) isolated. E. coli culture was treated with stannous fluoride in presence of phytic acid. As phytic acid altered the fixation of 99mTc on BC, on IF-P and on IF-BC and, moreover, it abolished the lethal effect of stannous fluoride on the E. coli culture, we can suggest that, probably, phytic acid would have chelating properties to the stannous ions.  相似文献   

6.
Summary This study describes a protocol for in vitro propagation of Chonemorpha grandiflora (Roth) S.M. & M.R. Almeida (Apocynaceae) through axillary bud proliferation and rooting. For shoot induction, the combination of 13.3 μM N 6-benzyladenine (BA) and 2.46 μM indole-3-butyric acid (IBA) in Murashige and Skoog (MS) medium was better than other growth regulators. Liquid medium was superior over solid medium for root formation and growth. IBA was more effective than other auxins for root induction. Addition of silver nitrate in the presence of IBA significantly increased the number, length, and branching of roots. Shoot tips encapsulated in medium containing 0.49 μM IBA and 11.7 μM silver nitrate exhibited 95% conversion to plantlets. This protocol enables the production of 250 plantlets from a single nodal explant within 7 mo. Plantlets showed 90% survival after acclimatization in soil and were morphologically similar to the source plant under field conditions.  相似文献   

7.
Abstract

Apple pomace was explored as alternative feedstock for producing bacterial cellulose (BC) by Gluconacetobacter xylinus following a cellulase saccharification performed after pretreatment of 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). The dissolving process of apple pomace cellulose was observed by polarized light microscopy (PLM). As FT-IR and XRD results demonstrated, the IL pretreatment proved to be a physical process and no changes in the crystalline structure occurred during the pretreatment. However, the SEM result showed that more fissures and breakages appeared on the surface of pomace microfibers after IL-pretreating, which increased the contact area with cellulase and improved the enzymatic hydrolysis efficiency. An enhancing effect on the BC yield has been observed, 27% higher yield of BC obtained from hydrolysate as compared to sucrose-based medium indicates efficiency of IL-treated apple pomace to serve as high quality feedstock in BC production.  相似文献   

8.
Seven aerobic bacterial strains were isolated from pulp paper mill waste and screened for pentachlorophenol (PCP) tolerance on PCP containing mineral salt agar medium (MSM). The organism was characterized by 16S rDNA sequencing which showed 99.7% sequence similarity with Serratia marcescens. PCP degradation was routinely monitored with spectrophotometric analysis and further confirmed by HPLC analysis. Among seven strains, ITRC S7 was found to degrade up to 90.33% of 1.127 mM (300 mg/l) of PCP and simultaneous release of chloride ion (2.435 mM) emphasized the bacterial dechlorination in the medium in presence of glucose as an additional carbon and energy source under optimized condition within 168 h incubation. In absence of glucose bacterium was unable to utilize PCP indicating the phenomenon of co-metabolism. Bacterium was identified as S. marcescens (AY927692), was a novel and potential aerobic bacterial strain capable of degrading PCP in axenic condition. Further, this strain may be used for bioremediation of PCP containing pulp paper mill waste in the environment.  相似文献   

9.
A bacterium that produced a large amount of poly(γ-glutamic acid) (PGA) when it was grown aerobically in a culture medium containing ammonium salt and sugar as sources of nitrogen and carbon, respectively, was isolated from soil. The bacterium, strain TAM-4, was classified as Bacillus subtilis. The maximum PGA production (22.1 mg/ml) was obtained when it was grown in a medium containing 1.8% ammonium chloride and 7.5% fructose at 30°C for 96 h with shaking. Some properties of the PGA obtained at different times of cultivation were investigated by gel permeation chromatography, SDS–PAGE, and measurement of viscosity, and calculation of the d/l ratio of glutamic acid constituting PGA. The results suggested that PGA was elongated with no changes in the diastereoisomer ratio in the molecule.  相似文献   

10.
A strain of Bacillus subtilis was examined for antifungal activity against phytopathogenic and wood-surface contaminant fungi. The bacterium was grown in five culture media with different incubation times in order to study cell development, sporulation, and the production of metabolites with antifungal activity. The anti-sapstain and anti-mould activity of the bacterium grown in yeast extract glucose broth (YGB) medium in wood was also evaluated. In YGB, the bacterium inhibited the growth of several fungi and displayed a broader spectrum of activity than in the other media tested. A relationship between bacterial spore production and the formation of metabolites with antifungal activity was detected. YGB medium displayed effective control in wood block tests. YGB medium was extracted with solvents of increasing polarity and the dry residues were applied to silicagel plates, resolved with the appropriate solvent and sprayed with different solutions, detecting the presence, of amines, and higher alcohols. The bioautographic method revealed the presence of at least two active compounds against the blue-stain fungus Cladosporium cucumerinum.  相似文献   

11.
Nitrogen fixation (acetylene reduction) was found in intact tomato (Lycopersicon esculentum Mill ‘Pusa Ruby’) plants in the field, in pots and also in aseptic cultures. The unsterilized as well as sterilized rhizoplane and phylloplane of the plant when assayed separately also responded to the test. From root bits of tomato sterilized upto 20 minutes with 0.1% mercuric chloride, growth of the bacterium from the interior of the root into the medium was observed thereby indicating their presence within the endorhizosphere. Phase contrast and electron microscopic studies of the root system of tomato revealed the presence of bacterial colonies in the epidermis, cortex and vascular bundles. Bacterial numbers in the endosphere, of root and leaf were 30×104 and 12×104, respectively, per gram fresh weight of tissue. The bacteria were predominantly rod-shaped 1.4–4.8×0.9–1.95 μm in 24-h-old cultures, pleomorphic, polar or bipolary flagellated having β-hydroxy butyrate granules. The bacterium has been identified as a new species of Azospirillum.  相似文献   

12.
The ion requirement for germination and outgrowth of endospores from the moderately halophilic salt marsh bacterium Halobacillus halophilus was studied. Germination and outgrowth of endospores plated onto nutrient broth was dependent on the salt concentration in the artificial seawater used as the source of ions. Maximal germination and outgrowth were observed when double-concentrated artificial seawater was used. Replacement of chloride salts in the artificial seawater by other salts resulted in a complete loss of germination and outgrowth that was restored upon addition of chloride. To analyze the role of chloride more directly and quantitatively, a defined growth medium was used in which the artificial seawater was substituted by a solution of magnesium sulfate and sodium chloride. Spore germination and outgrowth were strictly dependent on the chloride concentration; maximal germination and outgrowth were observed at ≈ 1.3 M Cl. Chloride could be substituted by bromide, but not by sulfate or nitrate. Microscopic examinations of single spores clearly showed that germination is the chloride-dependent step. This first report on chloride dependence of spore germination in any endospore-forming bacterium adds another function to chloride in H. halophilus apart from its being essential for the physiology of the vegetative cell. Received: 21 May 1999 / Accepted: 26 July 1999  相似文献   

13.
Summary This study reports an efficient and direct shoot bud differentiation and multiple shoot induction from nodal segments of underground stoloniferous rhizomes of Houttuynia cordata Thumb. The frequency of shoot bud regeneration was influenced by the type of cytokinin and concentrations. Among the various concentrations used, benzylaminopurine (BAP, 17.74 μM) or kinetin (Kn, 18.58 μM) was found to be most effective for rapid and maximum shoot but differentiation. The number of shoots per explant was higher (20.00±2.61) on Murashige and Skoog (MS) medium supplemented with Kn (18.58 μM) compared to BAP and 6-γ-γ-(dimethyl-allylamino)-purine (2iP) during initial 40-d-old culture. Subsequent shoot differentiation and multiplication were achieved in MS medium containing 9.29 μM Kn and 15% (v/v) coconut milk. Elongation and growth of multiple shoots were also obtained on MS medium containing either 2.32 μM Kn or 2.46 μM 2iP alone. The rate of shoot multiplication during subcultures declined with an increase in the size of proliferating shoot cluster. Reducing shoot cluster size to three to four shoots and subculturing together in shoot multiplication medium resulted in a better shoot multiplication and growth, which could be maintained for 2 yr. The elongated shoots (>20 mm) were successfully rooted on MS medium supplemented with 19.60 μM indole-3-butyric acid. Regenerated plants were successfully established in soil and were found to be healthy and uniform. The protocol reported in this study can be used for conservation and utilization of elite clone of H. cordata.  相似文献   

14.
A soil bacterium isolated from a contaminated site degraded phenol when provided as the sole carbon and energy source in the medium. The bacterium was identified as Xanthobacter flavus MTCC 9130. This microbial strain was able to tolerate phenol up to 1000 mg L?1 concentration. The lag phase increased with the increase in phenol concentration. The optimum growth temperature was 37°C. The organism efficiently utilized phenol and could degrade it completely within 120 h when initial concentration was less than 600 mg L?1. Degradation of phenol was through ortho pathway, enzyme assay through cell-free extract exhibited the presence of catechol 1,2-dioxygenase. The specific activity was 0.146 μ mol min?1 mg?1 protein. However, higher concentrations of phenol in the medium had a negative effect on the growth of the bacterium. Hence this ability of Xanthobacter flavus can be effectively used for bioremediation studies of phenol-contaminated sites.  相似文献   

15.
Summary This study investigated factors affecting the production of somatic embryos in Blighia sapida (ackee). Explants obtained from fully expanded leaves or cotyledons of immature zygotic embryos excised from brown (BSCZE) or green seeds (GSCZE) were cultured on Murashige and Skoog medium supplemented with 9, 18 and 36μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.4 or 22.1 μM benzylaminopurine (BAP) or 0.2–19.9 μM thidiazuron (TDZ). Leaf explants grown on media supplemented with the different combinations of 2,4-D and BAP formed callus, but they were non-embryogenic, while explants were not responsive on TDZ-supplemented media. GSCZE explants grown in the presence of 2,4-D/BAP combinations of 9/4.4, 18/4.4 or 36/4.4 μM formed non-embryogenic callus profusely, but explants gave rise to organized globular protuberances (GPs) and non-embryogenic callus on media containing TDZ, with the best concentration at 0.4 μM. BSCZE explants grown on TDZ-supplemented media also formed callus, but no GPs were detected. When GPs were cultured on media containing TDZ and abscisic acid they (ABA), gave rise to the highest number of somatic embryos. The medium was also beneficial for the development of somatic embryos from the globular to cotyledonary stage.  相似文献   

16.
Increasing numbers of studies are using Aliivibrio fischeri (A. fischeri), a marine bioluminescent bacterium as a model, however the culture medium used for its growth are complex and expensive. The objectives of this study were: (1) to evaluate the effect of yeast extract, tryptone, and NaCl to select a simple and inexpensive culture medium suitable for A. fischeri growth and bioluminescence induction; and (2) to compare the performance of mathematical models to predict the growth of A. fischeri. A fractional factorial design was performed to evaluate the effect of yeast extract, tryptone, and sodium chloride on the luminescence of A. fischeri. The result showed that sodium chloride is the most important factor, congruent with its inducer role in bioluminescence. The best medium for bioluminescence induction was selected through an optimization plot, this medium is inexpensive, and generates the same luminescence as commercial formulations. The estimation of A. fischeri growth at OD600 measurement was statistically analyzed. All evaluated models fitted the data adequately (r2  > 0.96). The nonlinear models Gompertz, Richards and logistic provided a lower variation and a better fit of the growth estimation (r2 >0.99), showing that these mathematical models can be used for the accurate growth prediction of A. fischeri.  相似文献   

17.
The interrelations between biochar (BC) and soil microbiota remain unclear. Addressing this will be important for understanding how BC affects soil properties and plant growth. Here, we tested the influence of wood-derived BC with immobilised Trichoderma viride on rye Secale cereale L. in sandy soil. We found that the addition of BC leads to a significant (P?2+ and Mg2+, as well as a decrease in the concentration of Al3+, irrespective of BC particle size and the presence of T. viride. Plant growth was stimulated in the presence of small (<2?mm) particle-sized BC. Fungal diversity, as well as an absolute and relative abundance of Trichoderma spp., was tested by cultivation-dependent methods and qPCR. Both of these approaches revealed a positive effect of BC on the survival of Trichoderma spp. under the tested conditions, especially in the presence of a small particle size fraction.  相似文献   

18.
A bacterium that assimilates (S)-3-chloro-1,2-propanediol [monochlorohydrin (MCH)] was isolated from soil by enrichment culture. The bacterium was identified as Pseudomonas sp. by taxonomic studies. The strain grew in a medium containing racemic MCH as a source of carbon and degraded (S)-MCH stereoselectively, liberating chloride ions. The residual isomer was the (R)-form [99.5% enantiomeric excess (ee)], which was obtained from the racemate in a final yield of 36% by using this strain. Subsequently, highly optically active (R)-glycidol (GLD) (99.3% ee) was prepared from the (R)-MCH obtained by reaction in alkaline solution. The cell-free extracts of the cells had both dehalogenating and epoxide-opening activities, which converted various halohydrins to the corresponding epoxides and epoxides to the corresponding diols, respectively. Correspondence to: T. Suzuki  相似文献   

19.
Summary Epithelial cells were scraped from the bladders of toads of the speciesBufo marinus obtained from the Dominican Republic. These epithelial cells exchanged their chloride virtually completely with36Cl in the medium within 60 min. Of this chloride, about 93% came from the serosal medium. The approximately 20 mmole/kg dry wt of chloride which equilibrates with36Cl in the mucosal medium was still present when choline replaced sodium in the medium in the presence of amiloride (10–4 M) and was almost all readily removed by rapid washing of the mucosal surface immediately prior to analysis. These observations suggest that little chloride of mucosal origin is truly intracellular. This conclusion is supported by the fact that after vasopressin the increased cellular chloride was not of mucosal origin.  相似文献   

20.
A methanol-utilizing bacterium, which produced red to pink pigments and assimilated methanol via icl- serine pathway, was isolated from soil and tentatively designated as Pseudomonas MS 31. This bacterium produced L-serine when glycine was added to the growth medium at the late exponential phase of growth. The cells showed high L-serine degradation activity. Chelating agents and some metal ions, which inhibited L-serine degradation, stimulated the L-serine accumulation. In the presence of 0.1 ? 1 mM EDTA, o-phenanthroline, 8-hydroxyquinoline, α,α'-dipyridyl, cobalt sulfate or nickel sulfate, this bacterium produced 0.7?2.1mg L-serine from 4mg glycine per ml culture.  相似文献   

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