• Microbiology and Biotechnology Letters
• /
• v.14 no.6
• /
• pp.479-485
• /
• 1986

A 5200 basepair DNA fragment containing the Bacillus amyloliquefaciens amyE gene, encoding liquefying $\alpha$-amylase (1,4-$\alpha$-1)-glucan glucanohydrolase, EC 3.2.1.1), has been inserted into BamHI site of the pUB110 and the hybrid plasmid was designated as pSKS3. The pSKS3 was transformed into the Bacillus subtilis KM2l3 as a host which is a saccharifying $\alpha$-amylase deficient mutant of Bacillus subtilis NA64, and the plasmid in the transformed cell was expressed $\alpha$-amylase production and kanamycin resistance. The $\alpha$-amylase production of the transformed cell was reduced to one fifth of that of the donor strain. The Bacillus subtilis KM2l3 tarring pSKS3 indicated that the amyE gene product is a polypeptide which has the same electrophoretic mobility with that of the Bacillus amyloliquefaciens, but different from the saccharifying $\alpha$-amylase of Bacillus subtilis NA64. It means that the amyE gene of pSKS3 originales from the Bacillus amyloliquefaciens.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.12
• /
• pp.1938-1944
• /
• 2008

The procpb gene encoding human procarboxypeptidase B (proCPB, GeneBank access code AJ224866) was cloned and its Pichia expression plasmid, $pPIC9{\alpha}$/hproCPB (9.2 kb), was constructed, in which procpb was under the control of the AOXl promoter and connected to the downstream of the mating factor ${\alpha}$-1 ($MF{\alpha}1$) signal sequence. The plasmid was linearized by digestion with Sacl, and integrated into the genome of P. pastoris strain GS115. By culturing of Pichia transformant on methanol medium, the human proCPB was successfully expressed and secreted into the culture supernatant. Moreover, Western blot analysis of the extracellular proteins showed proCPB bands clearly at a molecular mass of 45 kDa, confirming the expression of proCPB with its right size. The CPB activity reached about 3.5 U/ml and 12.7 U/ml in the flask and fermentor batch cultures of Pichia transformant, respectively. No CPB enzyme activity was found in the intracellular fraction. When the fed-batch cultivation was performed with methanol and glycerol mixture as a feeding medium, the extracellular CPB activity was increased to 42.0 U/ml, which corresponds to a 3.3-fold higher level of CPB activity than that of batch culture. The $K_m$ and $k_{cat}$ values of recombinant human CPB enzyme for hippuryl-$_L$-Arg as a substrate were estimated to be 0.16 mM and $11.93\;sec^{-1}$, respectively.

• Microbiology and Biotechnology Letters
• /
• v.48 no.2
• /
• pp.185-192
• /
• 2020

The global carbon storage regulator (Csr) system is conserved in bacteria and functions as a regulator in the exponential and stationary phases of growth in batch culture. The Csr system plays a role in the central carbon metabolism, virulence, motility, resistance to oxidative stress, and biofilm formation. Although the Csr was extensively studied in Gram negative bacteria, it has been reported only in the control of motility in Bacillus subtilis among Gram positive bacteria. The goal of this study was to explore the role of the csrA gene of Bacillus licheniformis M2-7 on motility and the bacterial ability to use hydrocarbons as carbon source. We deleted the csrA gene of B. licheniformis M2-7 using the plasmid pCsr-L, harboring the spectinomycin cassette obtained from the plasmid pHP45-omega2. Mutants were grown on culture medium supplemented with 2% glucose or 0.1% gasoline and motility was assessed by electron microscopy. We observed that CsrA negatively regulates motility by controlling the expression of the hag gene and the synthesis of flagellin. Notably, we showed the ability of B. licheniformis to use gasoline as a unique carbon source. Our results demonstrated that CsrA is an indispensable regulator for the growth of B. licheniformis M2-7 on gasoline.

• Journal of Life Science
• /
• v.25 no.6
• /
• pp.631-637
• /
• 2015

Streptavidin, a protein produced by Streptomyces avidinii, strongly binds up to four molecules of vitamin H, d-biotin exhibiting the dissociation constant of about 10⁻¹⁵ M. This strong binding affinity has been applied for detection and characterization of numerous biological molecules suggesting expression and purification of functional streptavidin should be very useful for the application of this streptavidin-biotin interaction. To express a soluble streptavidin in Escherichia coli, We synthesized streptavidin genes and cloned into pET-22b plasmid, which uses T7 RNA polymerase/T7 promoter expression systems containing pelB leader for secretion into periplasmic space and six polyhistidine tags at C-terminus for purification of expressed proteins. Although streptavidin is toxic to Escherichia coli due to strong biotin binding property, streptavidin was expressed very sufficiently in a range of 10-20 mg/ml. In SDS-PAGE, the size of purified protein was shown as 17 kDa in denatured condition (boiling) and 68 kDa in native condition (without boiling) suggesting tetramerization of monomeric subunit by non-covalent association. Further analysis by size-exclusion chromatography supported streptavidin’s tetrameric structure as well. In addition, soluble streptavidin detected biotinylated proteins in westernblot indicating its functional activity to biotin. Taken these results together, it concluded that our simple expression system was able to show high yield, homotetrameric formation and biotin binding activity analogous to natural streptavidin.

• Journal of Pharmaceutical Investigation
• /
• v.41 no.2
• /
• pp.95-102
• /
• 2011

An amphiphilic cationic branched methoxy poly (ethylene glycol)-branched polyethylenimine - poly(L-phenylalanine) (mPEG-bPEI-pPhe) block copolymer was successfully synthesized by ring-opening polymerization (ROP) of N-carboxyanhydride of L-phenylalanine (Phe-NCA) with mPEG-bPEI for the preparation of more stable polyelectrolyte complex (PEC) included a hydrophobic interaction. mPEG-bPEI was firstly prepared by the coupling of mPEG and bPEI using hexamethylene diisocyanate (HMDI). The structural properties of mPEG-bPEI-pPhe copolymers were confirmed by $^1H$ NMR. The copolymers exhibited a self-assemble behavior in water above critical aggregate concentration (CAC) in the range of 0.01-0.14 g/L. The CAC of copolymers obviously depended on the hydrophobic block content in the copolymers (the value decreased with the increase of the pPhe block content). The cationic copolymers have the ability to form multi-interaction complex (MIC) with bovine serum albumin (BSA) and plasmid DNA through multi-interaction (electrostatic and hydrophobic interaction). The physicochemical characterization of the complex was carried out by the measurement of zeta potential and particle size. Their zeta-potentials were positive (approximately +10 mV) and their sizes decreased with increasing pPhe contents in the copolymers (PPF/BSA wt% ratio = 2). The complex showed good stability at high ionic strength. Therefore, mPEG-bPEI-pPhe block copolymer was considered as a potential material to enhance the stability of complex including biotherapuetic drugs.

• Journal of Life Science
• /
• v.19 no.5
• /
• pp.566-572
• /
• 2009

A recombinant plasmid, pDH3, was obtained from the genomic library of Serattia marcescens KCTC 2172, and several recombinant subclones constructed from pDH3. The nucleotide sequence of a 5,137 bp segment, pPH4, was determined and three open reading frames were detected. The three ORFs encoded the phosphate specific transport (pst) operon, which was pstC, pstA, and pstB, with the same direction of transcription. Comparison of the pst operon of S. marcescens with that of other organisms revealed that the genes for pstS and phoU were missing. A potential CRP bonding site and pho box sequence was found in the upstream of the putative promoter at the regulatory region. Analysis of the nucleotide sequence showed that homology in amino acid sequences between the PstC protein and Yersinia sp., Vibrio sp., and Pseudomonas sp. were 49, 37 and 33%, respectively. The PstA protein and Yersinia sp., Vibrio sp., and Pseudomonas sp. showed homologies of 64, 51, and 47%, respectively. PstB protein and Methanocaldococcus sp., E. coli, and Mycoplasma sp. showed homologies of 60, 50, and 48%, respectively. The pst genes could be expressed in vivo and positively regulated by cAMP-CRP. The E. coli strain harboring plasmid pPH7, with pst genes, increased with the transport of phosphate.

• The Plant Pathology Journal
• /
• v.25 no.2
• /
• pp.136-141
• /
• 2009

Marking biocontrol bacteria is an essential step to monitor bacterial behavior in natural environments before application in agricultural ecosystem. In this study, we presented the simple green fluorescent protein (GFP) reporter system driven by the promoter active in Bacillus species for tagging of the biocontrol bacteria. A constitutive promoter P43 from Bacillus subtilis was fused to an enhanced promoterless gfp gene by overlap extension PCR. The GFP expression was demonstrated by the high fluorescence intensity detected in B. subtilis and Escherichia coli transformed with the P43-gfp fusion construct, respectively. The GFP reporter system was further investigated in two bacterial biocontrol strains B. licheniformis and Pseudomonas fluorescens. When the reconstructed plasmid pWH34G was introduced into B. licheniformis, GFP level measured with the fluorescence intensity in B. licheniformis was almost equivalent to that in B. subtilis. However, GFP expression level was extremely low in other biocontrol bacteria P. fluorescens by transposon based stable insertion of the P43-gfp construct into the bacterial chromosome. This study provides information regarding to the efficient biomarker P43-gfp fusion construct for bio-control Bacillus species.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.2
• /
• pp.244-250
• /
• 2000

An ${\alpha}-glucosidase$ gene (aglA) from thermophilic Bacillus sp. DG0303 was cloned, sequenced, and expressed in Escherichia coli. The aglA was localized to the 2.1-kb PvuI-XmnI region within the 5.9-kb DNA insert of the gybrid plasmid pAG1. The gene consisted of an open reading frame of 1,686 bp with an unusual GTG initiation codon and TGA termination codon. The amino acid sequence deduced from the nucleotide sequence predicted a protein of 562 amino acid residues with a M, of 66,551 dalton. A comparative amino acid sequence analysis revealed that DG0303 ${\alpha}-glucosidase$ is related to bacillary oligo-1, 6-glucosidases. The Bacillus sp. DG0303 ${\alpha}-glucosidase$ showed a high sequence identity (36-59%) to the B. flavocaldarius, B. cereus, and B. thermoglucosidasius oligo-1, 6-glucosidases. The number of prolines in theses four ${\alpha}-glucosidases. was observed to increase with increasing thermostability of these enzymes. The cloned ${\alpha}-glucosidase was purified from E. coli $DH5{\alpha}$ bearing pAG1 and characterized. The recombinant enzyme was identical with the native enzyme in its optimum pH and in its molecular mass, estimated by sodium dodecy1 sulfate-polyacrylamide gel electrophoresis. The temperature optimum of the cloned ${\alpha}-glucosidase$ was lower than that of the native enzyme.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.6
• /
• pp.1006-1010
• /
• 2010

Pseudomonas putida JM37 metabolized glyoxylate at a specific rate of 55 g/g dry biomass/day. In order to investigate their role, three genes encoding enzymes that are potentially involved in the conversion of glyoxylate were disrupted; namely, tartronate semialdehyde synthase (gcl), malate synthase (glcB), and isocitrate lyase (aceA). Strains with transposon insertion in either of these genes were isolated from a 50,000 clone library employing a PCR-guided enrichment strategy. In addition, all three double mutants were constructed via targeted insertion of a knock-out plasmid. Neither mutation of gcl, glcB, and aceA nor any of the respective double mutations influenced glyoxylic acid conversion, indicating that P. putida JM37 may possess other enzymes and pathways for glyoxylate metabolism.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.3
• /
• pp.355-362
• /
• 2000

The Herpes simplex virus type 1 (HSV-1) glycoprotein B (gB) gene in the pHLA-21 plasmid was inserted into a baculovirus (Hyphantria cunea nuclear polyhedrosis virus) expression vector (lacZ-HcNPV) to construct a recombinant virus gB-HcNPV expressing gB. Spodoptera frugiperda cells infected with this recombinant virus synthesized and processed gB of approximately 120 kDa, which cross-reacted with the monoclonal antibody to gB. The recombinant gB was identified on the membrane of the insect cells using an immunofluorescence assay. Antibodies to this recombinant raised in mice recognize the viral gB and neutralized the infectivity of the HSV-1 in vitro. These results show that the gB gene has the potential to be expressed in insect cells. They also demonstrate that it is possible to produce a mature protein by gene transfer in eukaryotic cells, and indicate the utility of the lacZ-HcNPV-insect cell system for producing and characterizing eukaryotic proteins. Furthermore, the neutralizing antibodies would appear to protect mice against HSV. Accordingly, this particular recombinant protein may be useful in the development of a subunit vaccine.