• Journal of agriculture & life science
• /
• v.46 no.2
• /
• pp.129-137
• /
• 2012

A carboxymethyl cellulase gene, cel5B, was cloned, sequenced, and expressed in Escherichia coli. pRCS20 in E. coli was identified from metagenomic cosmid library of cow rumen for cellulase activity on a carboxymethyl cellulose agar plates. Cosmid clone (RCS20) was partially digested with Sau3AI, ligated into BamHI site of pBluescript II SK+ vector, and transformed into E. coli $DH5{\alpha}$. The insert DNA of 1.3 kb was obtained, designated cel5B, which has the activity of hydrolyzation of CMC. The cel5B gene had an open reading frame (ORF) of 1,059 bp encoding 352 amino acids with a signal peptide of 48 amino acids and the conserved region, VIYEIYNEPL, belongs to the glycosyl hydrolase family 5. The molecular mass of Cel5B protein expressed from E. coli $DH5{\alpha}$ exhibited to be about 34 kDa by CMC-SDS-PAGE. The optimal pH was 8.0, and the optimal temperature was about $50^{\circ}C$ for its enzymatic activity.

• Journal of Food Hygiene and Safety
• /
• v.15 no.1
• /
• pp.55-59
• /
• 2000

In order to develop a antimicrobial agent, dried bamboo trunk was extracted by high temperature suction and then antimicrobial activities against Staphylococcus aureus ATCC 2825 and Escherichia coli DH 5$\alpha$ were investigated as compared with tea tree oil and BHA. The minimal inhibitory concentrationo(MIC) of the extracted substance against microorganisms were also examined. The results are as follows: 1. By disc diffusion method, BHA showed the strongest antimicrobial activity on Gram-positive bacteria such as S. aureus ATCC 2825 but bamboo essential oil showed the strongest antimicrobial activity on Gram-negative bacteria such as E. coli DH 5$\alpha$. 2. By broth dilution method, the minimum inhibitory concentration of the BHA, tea tree oil and bamboo oil were not detected against S. aureus ATCC 2825(MIC, 6.0 $\mu$l/ ml) and E. coli DH 5$\alpha$(MIC, 6.0 $\mu$l/ ml)

• Journal of Microbiology and Biotechnology
• /
• v.19 no.9
• /
• pp.982-986
• /
• 2009

For the production of ghost bacteria vaccine to prevent the streptococcal disease in aquaculture fish species, a double cassettes vector was constructed and cloned in Escherichia coli DH5${\alpha}$. Ghost bacteria vaccine production from Escherichia coli DH5${\alpha}$/pHCE-InaN-GAPDH-Ghost 37 SDM (SIG) was maximized at a glucose concentration of 1 g/l, agitation of 300 rpm, and aeration of 1 vvm. The maximal efficiency of ghost bacteria formation was obtained at the mid-exponential phase ($OD_{600}=2.0$) with the concentration of 0.77 g/l for SIG. The molecular mass of GAPDH was detected at 67 kDa with the insoluble fraction, by SDS-PAGE and Western blot. The protective efficacy of ghost bacteria vaccine was evaluated by challenge test using olive flounder. The cumulative mortalities of the positive control, formalin-killed cell (FKC) vaccine, and SIG vaccine immunized groups were 91%, 74%, and 57%, respectively. These results suggest that SIG vaccine showed efficacy as a vaccine and had a higher potential to induce protective antibodies than did FKC vaccine.

• Journal of Korean Society on Water Environment
• /
• v.28 no.6
• /
• pp.911-916
• /
• 2012

Recently, antibiotic resistant genes (ARGs) in the environment are emerging as pollutants, since these genetic contaminants can eventually be transferred to human pathogens. The aim of this study was to develop the experimental model of antibiotic resistant gene (ARG) plasmid transfer as a function of various environmental conditions. For this purpose, the multi drug resistant plasmid pB10, which is known to be originally isolated from a wastewater treatment plant, was selected as a model transfer plasmid and Escherichia coli $DH5{\alpha}$ containing pB10 was used as a model donor. Pseudomonas aeruginosa, an opportunistic pathogen, was selected as the recipient for the conjugation experiment. When the donor and recipient were exposed to various stressors including antibiotics and heavy metal as a function of the concentrations (10, 100 and, 1000 ppb), statistically increased plasmid transfer rate was observed at a concentration of 10 ppb of tetracycline and sulfamethoxazole compared to control (no antibiotic exposure). Accordingly, the developed experimental ARG model by various stressor is a promising tool for evaluating the dissemination of ARGs by micro-contaminants in aquatic environment.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.1
• /
• pp.20-24
• /
• 2006

Plasmid DNA (pDNA) is a product of interest for many biopharmaceutical companies and research laboratories, because of increase in the number of gene therapy protocols that use nonviral vectors. This work was undertaken to study the effect of antibiotic and dissolved oxygen concentration (DOC) on the production of a ColE 1-type plasmid (pVAX1-LacZ) hosted in Escherichia coli $DH5\alpha$ and cultured in a batch fermentor with 0.751 of Terrific Broth. A decrease in the DOC from $60\%\;to\;5\%$ was shown to increase the specific pDNA concentration approximately 1.5-fold, due to the downregulation of growth. Additionally, this increase in the pDNA concentration led to a 2.2-fold increase in the purity of cell lysates obtained after cell lysis. However, the use of higher DOC led to 2.8-fold higher volumetric productivity as a consequence of a faster growth rate, reducing the fermentation time from 24 to 8 h. Interestingly, the specific pDNA concentration, and pDNA productivity and purity were always higher $(10-15\%)$ in the absence of antibiotic. Overall, the data indicate that nonselective conditions can be used without compromising yield, productivity, and purity of pDNA.

• Applied Biological Chemistry
• /
• v.38 no.2
• /
• pp.118-122
• /
• 1995

Escherichia Coli ornithine transcarbamylase is the enzyme which catalyzes the L-citrulline biosynthesis from L-ornithine and carbamyl phosphate. To facilitate the purification of enzyme which will be used for many biochemical studies such as structure and function relationships and catalytic mechanisms, the cloning and expression of E. coli argI gene for ornithine transcarbamylase was conducted. argI was amplified from genomic DNA of E. coli strain of $DH5{\alpha}$, by polymerization chain reaction (PCR) method. The amplified argI gene was ligated to the prokaryotic expression vector pKK223-3 and used for transformation of E. coli TB2 which was deficient of ornithine transcarbamylase. The over-produced enzyme by the tnansformant was purified by ammonium sulfate fractionation, heat denaturation and affinity chromatography. The result of SDS denaturation gel electrophoresis for the purified enzyme showed a single band of about 38 kDa of ornithine transcarbamylase. Kinetic data for the expressed enzyme gave almost the s?????? values as those of the wild type enzyme. The $k_{cat}$, of the enzyme was $1.0{\times}10^5min^{-1}$, and $K_ms$ for ornithine and carbamyl phosphate were 0.35 mM and 0.06 mM, respectively.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.2
• /
• pp.275-280
• /
• 2000

The inulin fructotransferse (depolymerizing) (IFTase, EC 2.4.1.93) gene of Arthrobacter sp. A-6 was cloned and expressed in Escherichia coli and Bacillus subtilis. The IFTase gene consisted of an ORF of 1.311 nucleotides encoding a polypeptide of 436 amino acids containing a signal peptide of 31 amino acids in the N-terminus. The molecular mass of the IFTase based on the nucleotide sequence was calculated to be 46.116 Da. The recombinant E. coli $DH5{\alpha}$ cells expressing the Arthrobacter sp. A-6 IFTase gene produced most of the IFTase intracelularly. In contrast, the recombinant B. subtilis DB 104 carrying the IFTas gene on a B. subtilis-E. Coli expression vector secreted the IFTase into the culture fluid efficiently.

• Microbiology and Biotechnology Letters
• /
• v.37 no.3
• /
• pp.197-203
• /
• 2009

An indole oxygenase originated from Rhodococcus sp. RHA1 was cloned into the expression vector, pTrc99A, in Escherichia coli, and designated pTCAN1. The pTCAN2 was constructed from pTCAN1 by the deletion of $lacI^q$ for the constitutive expression of indole oxygenase without adding IPTG in the medium. The complete open reading frame of indole oxygenase was 1,224 bp long, which encodes a protein of 407amino acids. Crude extracts of E. coli $DH5{\alpha}$/pTCAN1 and pTCAN2, respectively, were prepared and subjected to SDS-PAGE analysis. A band corresponding to molecular mass of about 43 kDa was appeared and this result correlated with the predicted molecular mass of cloned indole oxygenase. The E. coli harboring pTCAN1 and pTCAN2, respectively, showed blue color colony in LB plate. The pigment showing blue color was prepared from E. coli $DH5{\alpha}$/pTCAN2, and identified as indigo by experiments using spectrophotometer, HPLC, and TLC. The indigo-forming activity of indole oxygenases from the whole cell of E. coli $DH5{\alpha}/pTCAN1$ cultured at LB medium added 1mM of IPTG and that of E. coli/pTCAN2 showed about 1.75nmol/min/mg DCW (dry cell weight) and 3.85 nmol/min/mg DCW, respectively. Also, the E. coli $DH5{\alpha}$/pTCAN2 produced about $236{\mu}M$ of indigo after 48 hours incubation in TB medium supplemented with 2.5 mM of tryptophan.

• Journal of Microbiology and Biotechnology
• /
• v.7 no.5
• /
• pp.293-298
• /
• 1997

A 4.6-kb HindIII fragment encompassing the complete 140-kDa ${\alpha}$-amylase gene of Lactobacillus amylovorus B 4540 was cloned into pBR322 by the shot gun method. Southern blotting and restriction mapping for the insert were performed. The recombinant 9.0-kb plasmid, pFML1, conferred ${\alpha}$-amylase activity to E. coli and Lactococcus lactis hosts when introduced by electroporation. SDS-PAGE and zymography confirmed the production of 140-kDa ${\alpha}$-amylase and its proteolytic degradation products with enzyme activity in transformants. Total ${\alpha}$-amylase activity of E. coli $DH5{\alpha}$ cells harboring pFML1 was 1.8 units and most activity was detected from cell pellets. Total enzyme activity of L. lactis subsp. lactis MG1363 transformant was five to ten-fold lower than that of E. coli cell but more than half of the activity was detected in the culture supernatant.

• Korean Journal of Microbiology
• /
• v.52 no.1
• /
• pp.110-115
• /
• 2016

A small plasmid (pDK4) from the Antarctic marine organism Pseudoalteromonas sp. PAMC 21150, was purified, sequenced and analyzed. pDK4 was determined to be 3,480 bp in length with a G+C content of 41.64% and contains three open reading frames encoding a replication initiation protein (RepA), a conjugative mobilization protein (Mob) and a hypothetical protein. PCR-amplified pDK4 was cloned in high-copy pUC19 to yield the fusion vector pDOC153. The chloramphenicol resistance gene was inserted into pDOC153 to give an ampicillin and chloramphenicol-resistant, Pseudoalteromonas - Escherichia coli shuttle vector (7,216 bp; pDOC155). The TonB-dependent receptor (chi22718_IV ) and exochitinase (chi22718_III ) genes from Arctic marine P. issachenkonii PAMC 22718 were cloned into pDOC155 to produce pDOC158 and pDOC165, respectively. Both vector derivatives were transferred into plasmid-free Pseudoalteromonas sp. PAMC 22137 by the triparental mating method. PCR experiments showed that the genes were stably maintained both in Pseudoalteromonas sp. PAMC 22137 and E. coli $DH5{\alpha}$ cells, indicating the potential use of pDOC155 as a new gene transfer system into marine Pseudoalteromonas spp.