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Watanalai Panbangred Eiichiro Fukusaki Evangeline C. Epifanio Atsuhiko Shinmyo Hirosuke Okada 《Applied microbiology and biotechnology》1985,22(4):259-264
Summary A hybrid plasmid, pOXN29 (10.4 Mdal), coding the xylanase (xynA) and -xylosidase (xynB) genes of Bacillus pumilus IPO was constructed by the ligation of pBR322 and a 7.7 Mdal PstI-fragment of chromosomal DNA as reported in our previous paper (Panbangred et al. 1983). A deletion plasmid of pOXN29, pOXN293 (9.2 Mdal), which contains xynA and xynB, was ligated with pUB110 at an EcoRI site, and used to transform B. subtilis MI111. Two selected clones of B. subtilis as xylanase hyper-producers contained plasmids pOXW11 (4.2 Mdal) and pOXW12 (4.0 Mdal), both consisting of only pUB110, xynA, and its flanking regions, as the result of spontaneous deletion. These B. subtilis clones produced 2.7–3.0 times as much xylanase as B. pumilus.
Escherichia coli and B. subtilis clones harbouring the hybrid plasmids synthesized xylanase and -xylosidase constitutively, whereas both enzymes were induced by xylose in B. pumilus.Xylanase synthesized by B. subtilis harbouring pOXW11 or pOXW12 was excreted into the medium like that of B. pumilus IPO, but xylanase synthesized in E. coli harbouring pOXN29, 293 or pOXW1 coding xynA was intracellular. In a previous investigation (Panbangred et al. 1983), xylanase was found to be located in the cytoplasm, not the periplasm nor the membrane fraction in E. coli cells harbouring pOXN29 derivatives. In spite of the abnormal location of xylanase synthesized in E. coli, the signal peptide was processed in the same way as in B. pumilus, with the same molecular weight and the same amino terminal sequences of xylanase prepared from E. coli cells and B. pumilus culture fluid. 相似文献
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Bacillus probiotics: an alternative to antibiotics for livestock production 总被引:1,自引:0,他引:1 下载免费PDF全文
The use of probiotics as feed supplements in animal production has increased considerably over the last decade, particularly since the ban on antibiotic growth promoters in the livestock sector. Several Bacillus sp. are attractive for use as probiotic supplements in animal feed due to their ability to produce spores. Their heat stability and ability to survive the low pH of the gastric barrier represent an advantage over other probiotic micro‐organisms. This review discusses important characteristics required for selection of Bacillus probiotic strains and summarizes the beneficial effect of Bacillus‐based feed additives on animal production. Although the mechanism of action of Bacillus probiotics has not been fully elucidated, they are effective in improving the growth, survival and health status of terrestrial and aquatic livestock. Bacillus strains also have utility in bioremediation and can reduce nitrogenous waste, thereby improving environmental conditions and water quality. Finally, recent innovative approaches for using Bacillus spores in various applications are discussed. 相似文献
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Chanpen Wiwat Watanalai Panbangred Amaret Bhumiratana 《Journal of industrial microbiology & biotechnology》1990,6(1):19-27
Summary The plasmids pBC16 and pC194 fromBacilus thuringiensis subsp.israelensis strains A084-16-194 were transferred to 25 subspecies ofB. thuringiensis by a conjugation-like process using broth mating technique. The frequencies of transfer varied considerably between different mating pairs, ranging from 1.1×10–9 to 9.8×10–5. Additionally, chromosomal transfer could also be demonstrated in tenB. thuringiensis subspecies with very low frequencies (4.3×10–9 to 3.7×10–7). The intersubspecies matings within a group of eight subspecies strains gave higher frequencies of transfer than the matings between the subspecies. Furthermore, the results indicated that the capability to transfer plasmids among these various subspecies did not depend on the presence of large plasmid. 相似文献
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Ngamwongsatit P Banada PP Panbangred W Bhunia AK 《Journal of microbiological methods》2008,73(3):211-215
Bacillus cereus continues to be one of the important foodborne pathogens due to its ability to produce various heat-labile and -stable toxins. Several methods have been developed to assess the pathogenicity of the B. cereus strains; however, most of these take more than 2–3 days to provide confirmatory results. In this study we standardized a one-step cytotoxicity assay using WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) and compared with the traditional MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide)-based assay for rapid detection of cytotoxic Bacillus spp. using Chinese hamster ovary (CHO) cell line. Crude toxin preparations from 50 isolates of Bacillus spp. were exposed to CHO cell line for 1 h or 24 h and the cytotoxicity was determined by using WST-1 and MTT-based methods. Most B. cereus strains and some strains of other Bacillus species from our collection or from food sources showed comparably high cytotoxicity using either of the methods (P = 0.81); however, WST-1 assay provided results in only 3 h while MTT assay in 44–52 h. A positive correlation (R2 = 0.93) between WST-1 and MTT assays strongly suggests that the WST-1-based cytotoxicity assay could be used as an alternative method to MTT assay for rapid (3 h) confirmation of toxigenic Bacillus species in foods prior to their retail distribution or consumption. 相似文献
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Chanpen Wiwat Watanalai Panbangred Skorn Mongkolsuk Somsak Pantuwatana Amaret Bhumiratana 《Current microbiology》1995,30(2):69-75
Extraction of the S-layer protein by treatment with 6 m urea revealed a high-molecularweight protein in the extracts obtained from Bacillus thuringiensis subsp. israelensis (B.t.i) strain 4Q2. This protein band was found to be absent in partially cured (4Q2-72) and completely cured (c4Q2-72) strains. The antibody toward this S-layer protein was prepared and used to locate its antigenic protein on B.t.i cells by using indirect immunofluorescence. Immunodiffusion reactions and Western blot analysis confirmed the specificity of the anti-S-layer protein antibody. It was found that the antibody against 4Q2 S-layer protein, inhibited plasmid transfer via a conjugationlike process between, B.t.i. strains 4Q2-16 and c4Q2-72. That is, the frequency of transfer of plasmid pBC16 was reduced from 9.7×10-6 in the absence of the antibody to less than 1.0×10-8 in the presence of the antibody. The antibody was also found to reduce the frequency of pBC16 plasmid transfer via a conjugation-like process between B.t.i. strains A084-16-194 and c4Q2-72 from 2.2×10-5 in the absence of the antibody to 1.2×10-6 in the presence of the antibody. 相似文献
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N. Sriubolmas W. Panbangred S. Sriurairatana V. Meevootisom 《Applied microbiology and biotechnology》1997,47(4):373-378
Various concentrations of isopropyl β-d-thiogalactopyranoside (IPTG) were used to induce production of the enzyme penicillin G acylase by recom binant Escherichia coli harboring plasmid pQEA11. The plasmid pQEA11 carries a wild-type pga gene, which is under the control of the tac promoter and lacI q. At low IPTG concentrations (0.025 – 0.1 mM), enzyme activity increased with increasing IPTG concentrations. At higher IPTG
concentrations (0.2 and 0.5 mM), enzyme activity declined progressively. Examination of induced recombinant E. coli cells by transmission electron microscopy showed the presence of only periplasmic inclusion bodies at low IPTG concentrations
(up to 0.1 mM) and both periplasmic and cytoplasmic inclusion bodies at high IPTG concentrations (0.2 mM and 0.5 mM). Results
from sodium dodecyl sulfate/polyacrylamide gel electrophoresis and immunoblots of whole-cell proteins, membrane proteins and
inclusion body proteins in these cells indicated that cytoplasmic inclusion bodies constituted an accumulation of preproenzyme
(i.e., precursor polypeptide containing a signal peptide) and that periplasmic inclusion bodies constituted an accumulation
of proenzyme (i.e., precursor polypeptide lacking a signal peptide).
Received: 27 March 1996 / Received revision: 2 July 1996 / Accepted: 10 November 1996 相似文献
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W. Panbangred S. Panjaisee S. Tantimavanich 《World journal of microbiology & biotechnology》2000,16(2):163-169
The 3.7 kb XbaI fragment harbouring the cryIVB gene which encoded a 130 kDa mosquitocidal toxin protein from Bacillus thuringiensis subsp. israelensis (B.t.i.) was placed downstream to the cat-86 gene promoter (P
cat-86, spore stage specific expression) or bgaB gene promoter (P
bgaB
, vegetative stage specific expression). The constructs were subcloned into pBC16 to obtain pBTC3 and pBTC6, respectively. Both plasmids and the other construct, pBTC1 were successfully transferred into B. thuringiensis subsp. israelensis c4Q2-72 and B. sphaericus 2362. Western blot analysis showed that P
bgaB
in front of P
cryIVB
could enable cells to produce a 130 kDa protein from the vegetative stage (4 h) whereas those with P
cat-86 could not. The positive detection of 130 kDa crystal protein during the vegetative stage (4 h) by Western blot analysis indicated the vegetative-stage-specific expression of P
bgaB
, while the 130 kDa crystal protein produced from cryIVB gene under control of P
cat-86 was detected only at 48 h. The strong activity of P
bgaB
, together with P
cryIVB
within pBTC6 in both bacterial hosts was also shown by the toxicity assay against Aedes aegypti larvae (B.t.i. c4Q2-72, 5.6 ± 3.6 × 102 c.f.u./ml; B. sphaericus 2362, 5.4 ± 2.5 × 102 c.f.u./ml) which were 100-fold and 10-fold more toxic to such larvae when compared with pBTC3 (P
cat-86 together with P
cryIVB
) and pBTC1 (contained only its self promoter) in the same bacterial host strains, respectively. The plasmid pBTC6 is not stable in either Bacillus host. 相似文献