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1.
Purpose of work
Undecylprodigiosin has antimicrobial, immunosuppressive and anticancer properties. Pure cultures of Streptomyces coelicolor produce only low concentrations of undecylprodigiosin. We have therefore sought to increase this by interacting the cells with a bacterium. 相似文献2.
Bacterial biofilms are associated with chronic infections due to their resistance to antimicrobial agents. Staphylococcus
aureus is a versatile human pathogen and can form biofilms on human tissues and diverse medical devices. To identify novel biofilm
inhibitors of S. aureus, the supernatants from a library of 458 Actinomycetes strains were screened. The culture supernatants (1% v/v) of more than 10 Actinomycetes strains inhibited S. aureus biofilm formation by more than 80% without affecting the growth. The culture supernatants of these biofilm-reducing Actinomycetes strains contained a protease (equivalent to 0.1 μg proteinase K ml−1), which both inhibited S. aureus biofilm formation and detached pre-existing S. aureus biofilms. This study suggests that protease treatment could be a feasible tool to reduce and eradicate S. aureus biofilms. 相似文献
3.
Ae-Young Mo Bora Kwon Seralathan Kamala-Kannan Kui-Jae Lee Byung-Taek Oh Dae-Hyuk Kim Moon-Sik Yang Jin-Hyung Kim Seung-Moon Park 《World journal of microbiology & biotechnology》2010,26(6):1099-1105
Bacteria of the Bacillus species have been reported as an important microorganism in fermented soybean products. In the present study, thirty Bacillus isolates were screened from Meju, a Korean soybean fermentation starter. The comparative analysis of 16S rDNA sequences, 16S-23S internal transcribed spacer
sequences, phenotypic, and biochemical characterizations revealed three phylogenetically distinct groups namely Bacillus atrophaeus,
Bacillus polyfermenticus and Bacillus subtilis. The isolates were assayed for poly-γ-glutamate production and fibrinolytic activity. Among the isolates, B. polyfermenticus exhibited maximum poly-γ-glutamate production and fibrinolytic activity. Moreover, the soybean products fermented by B. polyfermenticus have increased the time taken for coagulation and hemorrhage in mice. The results of the present study clearly indicate the
functional role of B. polyfermenticus in fermented soybean products. 相似文献
4.
The toxigenic potential of Bacillus species isolated from the traditional fermented condiment okpehe was determined; this is aimed at selection of non-toxigenic bacilli as starter cultures to bring about production of safe
product. B. subtilis and B. cereus strains isolated from okpehe were evaluated for their possible possession of virulence characteristics. Fifty isolates were screened for their ability
to produce diarrhoea enterotoxin by reversed passive latex agglutination (BCET-RPLA) test kit; the result showed that 40%
of the B. cereus strains were toxigenic. The ability of the selected isolates to compete in situ and in vitro toxin production during the
fermentation was also determined. The enterotoxin was not detected using BCET-RPLA kit in the spontaneously fermented samples
of okpehe, but the toxin was detected in the okpehe samples fermented using B. cereus enterotoxin producer in mixed starter culture fermentation. The PCR amplification of virulence genes revealed that Bacillus cereus and B. licheniformis, a strain from the B. subtilis group, contained DNA sequences encoding the haemolysin BL (hblD) enterotoxin complex. The growth ability of B. cereus strains to high population during the fermentation and the presence of detectable diarroheagenic genes in B. cereus and B. licheniformis showed that strains carrying virulence characteristics cannot be totally ruled out in traditionally fermented okpehe. 相似文献
5.
Elicitation can lead to overproduction of secondary metabolites in plants and microbes. Potential changes in cytosolic Ca2+ levels in bacteria were studied in response to elicitation. We report, for the first time, the effect of oligosaccharide
elicitors on intracellular Ca2+ levels. The apoaequorin gene was cloned into Escherichia coli DH5α and Bacillus subtilis 1604 cultures. Addition of elicitors, oligoguluronate and mannan oligosaccharides, to the cultures caused up to 11-fold increase
in cytosolic Ca2+ in E. coli and tenfold increase in B. subtilis. These increases in Ca2+ levels could therefore contribute to the enhancement of secondary metabolite levels. 相似文献
6.
Archana Gajbhiye Alok R. Rai Sudhir U. Meshram A. B. Dongre 《World journal of microbiology & biotechnology》2010,26(7):1187-1194
Present investigation is based on the isolation of Bacillus subtilis from cotton rhizosphere and their evaluation as biocontrol agent against Fusarium oxysporum. The production of extracellular hydrolytic enzyme was studied for determining the antagonism. 43% of 21 isolates were identified
under the B. subtilis group on the basis of biochemical characterization. 38% isolates showed competitive activity against Fusarium oxysporum and exhibit more than 50% mycelial inhibition in dual culture bioassay. The pot assay of cotton by seed treatment and soil
amendment technique under green house condition showed the competent activity of the isolates in preventing the wilting of
cotton seedlings due to F. oxysporum infection. SVI values of 30 day old seedlings indicated that the soil inoculation with B. subtilis BP-2 and seed treatment with B. subtilis BP-9 significantly promoted the growth of cotton seedlings. RAPD profiling revealed the diversity in the Bacillus
subtilis group, ranging from 10 to 32%. The discriminative pattern among the isolates belonging to the same species was validated
by 16S rDNA partial sequencing which identified them into four different strains of B. subtilis. 相似文献
7.
Pellicle formation and lipopeptide production was analysed in standing cultures of different Bacillus subtilis strains producing two or three families of lipopeptides. Despite its ability to produce surfactin, B. Subtilis ATCC 6633 was unable to form stable pellicle at air–water interface. For the ATTC 21332 and ATCC 9943 strains, it was shown
for the first time that the lipopeptides were also produced in standing cultures at productivities similar or lower than those
obtained when the culture medium is agitated. A differentiated behaviour was observed between these strains in repetitive
batch cultures. B. subtilis 9943 formed a wrinkled, thinner and more resistant pellicle than B. subtilis 21332. The structure of the pellicle determined by electron microscopy observations showed that cells of B. subtilis 9943 formed microcolonies whereas those of B. subtilis 21332 rapidly died. Under these conditions, surfactin production by strain 21332 decreased after 2 days whereas it remained
stable for B. subtilis 9943 during the 6 days of the cultures. These data indicate that cells of B. subtilis strains growing in pellicle can produce lipopeptides differently depending on their cellular organisation.
M. Chollet-Imbert and F. Gancel have contributed equally to the scientific work. 相似文献
8.
Durban MA Silbersack J Schweder T Schauer F Bornscheuer UT 《Applied microbiology and biotechnology》2007,74(3):634-639
Twenty-two Bacillus cereus strains were screened for phospholipase C (PLC, EC 3.1.4.3) activity using p-nitrophenyl phosphorylcholine as a substrate. Two strains (B. cereus SBUG 318 and SBUG 516) showed high activity at elevated temperatures (>70°C) at acidic pH (pH 3.5–6) and were selected for
cloning and functional expression using Bacillus subtilis. The genes were amplified from B. cereus DNA using primers based on a known PLC sequence and cloned into the expression vector pMSE3 followed by transformation into
B. subtilis WB800. On the amino acid level, one protein (PLC318) was identical to a PLC described from B. cereus, whereas PLC516 contained an amino acid substitution (E173D). PLC production using the recombinant strains was performed
by an acetoin-controlled expression system. For PLC516, 13.7 U g−1 wet cell weight was determined in the culture supernatant after 30 h cultivation time. Three purification steps resulted
in pure PLC516 with a specific activity of 13,190 U mg−1 protein. 相似文献
9.
Lenka Tumova Katerina Gallova Jana Rimakova Martin Dolezal Jiri Tuma 《Acta Physiologiae Plantarum》2005,27(3):357-362
In vitro plant tissue and cell cultures were used to study herbicide effects on growth, selected metabolic activities and other phenomena.
The effect of abiotic elicitors, two newly synthesized substituted amides of pyrazine-2-carboxylic acids (synthesized at the
Department of Pharmaceutical Chemistry and Drug Control, School of Pharmacy in Hradec Kralove), on the flavonolignan accumulation
in callus and suspension culture of Silybum marianum (L.) Gaertn. was investigated. The compounds markedly influenced production of flavonolignans in an in vitro culture. Particularly after the elicitation with a solution of compound 3-methylamide 5-tert-butylpyrazine-2-carboxylic acid at a concentration of 3.71×10−7 mol 1−1 and within 72 h of elicitation, an increase in flavonolignan production by 893 % in suspension culture versus control took place. The flavonolignan accumulation in callus culture after the elicitation with a solution of 5-brom-2-hydroxyphenylamide
of 5-tert-butyl-6-chloropyrazine-2-carboxylic acid was also increased by about 1039% (24 hour elicitation and concentration of 2.59×10−4 mol 1−1). 相似文献
10.
Twenty-five Campylobacter isolates were screened for production of antimicrobial substances using a deferred antagonism assay. Sixteen isolates showed
activity against either Staphylococcus aureus, Salmonella enterica serovar Enteritidis or Candida albicans. The inhibitory activity was sensitive to treatment with pronase E, trypsin and pepsin, suggesting that the antimicrobial
compound(s) are proteinaceous. Activity spectra of isolates included S. aureus, Micrococcus luteus, Streptococcus sp., Bacillus subtilis, a drug-resistant clinical isolate of S. aureus and one isolate of C. albicans. Producing isolates showed cross-immunity and inhibitory activity was only observed on solid media. The findings of this
study suggest that Campylobacter produces proteinaceous inhibitory substances. 相似文献
11.
12.
13.
Background
B. subtilis is an important organism in the biotechnological application. The efficient expression system is desirable in production of recombinant gene products in B. subtilis. Recently, we developed a new inducible expression system in B. subtilis, which directed by B. subtilis maltose utilization operon promoter P glv . The system demonstrated high-level expression for target proteins in B. subtilis when induced by maltose. However, the system was markedly repressed by glucose. This limited the application of the system as a high-expression tool in biotechnology field. The aim of this study was to further improve the P glv promoter system and enhance its expression strength. 相似文献14.
Mendoza LM de Nadra MC Bru E Farías ME 《Journal of industrial microbiology & biotechnology》2009,36(2):229-237
The influence of two physicochemical factors involved in winemaking, temperature and SO2, on the kinetics and metabolic behavior of Kloeckera apiculata and Saccharomyces cerevisiae was examined. Highest biomass was reached at 15 and 25°C for K. apiculata and S. cerevisiae, respectively. Pure cultures of K. apiculata died off early with increasing temperature, but in co-culture with S. cerevisiae it showed higher viability and a change in the death curve from exponential to linear. Statistical analysis revealed that
metabolite production was significantly different for the three cultures and also at the different fermentation temperatures.
Besides, the interaction between culture type and temperature was significant. At temperatures from 15 to 30°C the mixed culture
showed similar ethanol and lower acetic acid production compared with a pure culture of K. apiculata. SO2 addition slightly increased survival of the non-Saccharomyces species in pure and mixed cultures. Statistical evaluation indicated that culture type and SO2 addition significantly affected metabolite production, but the interaction between culture and SO2 was not significant. These results contribute to current knowledge of enological factors and their effect on prevalence and
fermentative activities of the composite yeast flora and the statistical significance emphasizes the importance of the combined
influence of the culture type and physicochemical factors on the production of fermentation metabolites. 相似文献
15.
Streptomyces
coelicolor, the model species for morphologically complex actinomycete bacteria, has unique characteristics such as morphological and
physiological differentiation, which are controlled by various factors and several protein kinases. From the whole genomic
sequence of S. coelicolor A3(2), 44 putative serine/threonine (Ser/Thr) protein kinases were identified, and the pkaF gene was chosen as the best-conserved protein for typical Ser/Thr protein kinases. pkaF encodes a 667-amino acid protein with a predicted N-terminal Ser/Thr kinase domain and four repeated C-terminal penicillin-binding
domains and Ser/Thr kinase-associated (PASTA) domains. Based on PCR, a pkaF gene was cloned and heterologously expressed. PkaF expressed in Escherichia coli had the bigger molecular size than the expected value (75 kDa) and was further purified by Ni2+-NTA agarose affinity column chromatography to homogeneity. The purified PkaF was autophosphorylated through the transfer
of the γ-phosphate group of ATP. The extent of phosphorylation was proportional to the amount of PkaF, and the phospho-PkaF
was dephosphorylated by the addition of the cell lysate of S. coelicolor A3(2). Although no change was observed in the pkaF disruptant, overexpression of pkaF induced severe repression of morphogenesis and actinorhodin production, but not undecylprodigiosin production, implying that
PkaF specifically regulates morphogenesis and actinorhodin production in S. coelicolor. 相似文献
16.
Nattokinase producing bacterium, B. subtilis YF38, was isolated from douchi, using the fibrin plate method. The gene encoding this enzyme was cloned by polymerase chain reaction (PCR). Cytoplasmic
expression of this enzyme in E. coli resulted in inactive inclusion bodies. But with the help of two different signal peptides, the native signal peptide of nattokinase
and the signal peptide of PelB, active nattokinase was successfully expressed in E. coli with periplasmic secretion, and the nattokinase in culture medium displayed high fibrinolytic activity. The fibrinolytic
activity of the expressed enzyme in the culture was determined to reach 260 urokinase units per micro-liter when the recombinant
strain was induced by 0.7 mmol l−1 isopropyl-β-D- thiogalactopyranoside (IPTG) at 20°C for 20 h, resulting 49.3 mg active enzyme per liter culture. The characteristic
of this recombinant nattokinase is comparable to the native nattokinase from B. subtilis YF38. Secretory expression of nattokinase in E. coli would facilitate the development of this enzyme into a therapeutic product for the control and prevention of thrombosis diseases. 相似文献
17.
Okigbo RN 《Mycopathologia》2005,159(2):307-314
The potential of isolates of Bacillus subtilis from yam farm soil to control rot of yam in storage barns was investigated. Yam tubers inoculated in vivo with B. subtilis showed no rot while those inoculated with Aspergillus niger, Botryodiploidia theobromae or Penicillium oxalicum showed considerable rot. The set of yams in which B. subtilis and the fungi were simultaneously inoculated produced rot whereas those in which B. subtilis was inoculated a day before the fungi was inoculated were totally reduced or free of rot. Many fewer fungi were isolated from the surface of tubers treated with B. subtilis than from the untreated (control) and there was high recovery of B. subtilis (99–100%) throughout the period of storage. Rot build up was faster in uninoculated control tubers or those inoculated with a spoilage fungus, while those treated with the antagonist were totally reduced or free of rot. The culture filtrate of B. subtilis prevented spore germination in some spoilage fungi. The importance of this study in relation to farmers in developing countries is discussed. 相似文献
18.
The Streptomyces coelicolor genome contains 17 TerD domain-encoding genes (tdd genes) of unknown function. The proteins encoded by these genes have been presumed to be involved in tellurite resistance
on the basis of their homology with the protein TerD of Serratia marcescens. To elucidate the role of a Tdd protein (Tdd8), both a deletion mutant for the corresponding gene tdd8 (SCO2368) and a recombinant strain over-expressing tdd8 were produced in S. coelicolor M145. The deletion mutant (Δtdd8), like the wild strain, was not resistant to potassium tellurite. The deletion was not lethal but had a marked effect on
differentiation. The deletion strain showed more rapid growth in liquid medium and produced long chains of short spores with
a dense and non-spherical spore wall on agar plates. The strain over-expressing tdd8 had a growth delay in liquid medium and produced very few spores of irregular shapes and sizes on solid medium. The results
of this study demonstrated that Tdd proteins might have a function other than tellurite resistance and this function seems
to be of crucial importance for the proper development of the actinomycete S. coelicolor. 相似文献
19.
The bacterial strain Bacillus subtilis UTM 126 produced antimicrobial activity against pathogenic Vibrio species, including V. alginolyticus, V. parahaemolyticus, and V. harveyi. The probiotic effect of B. subtilis was tested by feeding juvenile shrimp (Litopenaeus vannamei) food supplemented with B. subtilis (105 CFU/g) for 28 days before an immersion challenge with V. harveyi at 105 CFU/mL for 24 h. The treatment with B. subtilis UTM 126 decreased final mortality to 18.25%, compared with 51.75% in the control group. Bacillus subtilis UTM 126 has potential applications for controlling pathogenic V. harveyi in shrimp aquaculture. 相似文献
20.
The results presented in this article show that direct plasmid transfer from Escherichia coli carrying shuttle plasmid to Bacillus subtilis occurred when close contact between the two species was established by mixing E. coli and B. subtilis onto selective agar plates. The data demonstrate that the production of resistant colonies by plasmid transformation through
cell contact was DNase I sensitive and dependent on transformable B. subtilis strains. Furthermore, another observation indicated that the E. coli strain is able to affect the transformation capability of B. subtilis. It is assumed that the donor strain is a momentous factor for taking up plasmid DNA. This conclusion is significant in the
assessment of both the possibility of intercellular DNA transfer in natural habitats of micro-organisms and the risk of the
application of genetically engineered micro-organisms. 相似文献