• BMB Reports
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• v.44 no.1
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• pp.1-10
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• 2011

Inter-cellular communication via diffusible small molecules is a defining character not only of multicellular forms of life but also of single-celled organisms. A large number of bacterial genes are regulated by the change of chemical milieu mediated by the local population density of its own species or others. The cell density-dependent "autoinducer" molecules regulate the expression of those genes involved in genetic competence, biofilm formation and persistence, virulence, sporulation, bioluminescence, antibiotic production, and many others. Recent innovations in recombinant DNA technology and micro-/nano-fluidics systems render the genetic circuitry responsible for cell-to-cell communication feasible to and malleable via synthetic biological approaches. Here we review the current understanding of the molecular biology of bacterial intercellular communication and the novel experimental protocols and platforms used to investigate this phenomenon. A particular emphasis is given to the genetic regulatory circuits that provide the standard building blocks which constitute the syntax of the biochemical communication network. Thus, this review gives focus to the engineering principles necessary for rewiring bacterial chemo-communication for various applications, ranging from population-level gene expression control to the study of host-pathogen interactions.

• Journal of fish pathology
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• v.8 no.1
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• pp.37-46
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• 1995

The amino acid analysis of polyhedrin protein and nucleotide sequence of polyhedrin gene in H. cunea nuclear polyhedrosis virus (HcNPV) genome have been studied. Polyhedrin had three polypeptide bands in SDS - polyactylamide gel electrophoresis. The major polypeptide had a molecular weight of 25 kd. The polyhedrin was composed of 17 different amino acids. HcNPV DNA was digested with EcoRI restriction enzyme and hybridized with ($\alpha^{32}P$) -labelled AcNPV polyhedrin gene cDNA. The polyhedrin gene was located on the fragment of EcoRI-H. The EcoRI - H fragment containing polyhedrin gene was cloned into the EcoRI site of pUC8 vector which was confirmed with southern blotting, and the recombinant plasmid containg polyhedrin gene was designated as hPE-H. The promoter region of polyhedrin genomic DNA was sequenced. The sequences identified as the TATA box was found at the 5' flanking region of the polyhedrin genomic DNA approximately -79 bp upstream from the transcriptional start site. But CAAT-like box was not shown near the TATA-like box in the polyhedrin gene. Four tandem repeats with the sequence 5' -CTAATAT-3' and 5'-TAAATAA-3' were found between -141 and -108 or -83 upstream and -52 bp downstream from the translation start site. About -141 bp region upstream from the translational start site was highly AT (78%) rich. The coding region for the polyhedrin starts and ends with ATG and TAA, respectively.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.788-796
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• 2023

Canine parvovirus type 2 (CPV-2) has high morbidity and mortality rates in canines. Nonstructural protein 1 (NS1) of CPV-2 has endonuclease activity, initiates viral DNA replication, and is highly conserved. Thus, it is a promising target for antiviral inhibitor development. We overexpressed a 41.9 kDa active recombinant endonuclease in Escherichia coli and designed a nicking assay using carboxyfluorescein and quencher-linked ssDNA as substrates. The optimal temperature and pH of the endonuclease were 37℃ and pH 7, respectively. Curcumin, bisdemethoxycurcumin, demethoxycurcumin, linoleic acid, tannic acid, and α-tocopherol inhibited CPV-2 NS1 endonuclease with IC₅₀ values of 0.29 to 8.03 µM. The extracted turmeric, yerba mate, and sesame cake suppressed CPV-2 NS1 endonuclease with IC₅₀ values of 1.48, 7.09, and 52.67 ㎍/ml, respectively. The binding affinity between curcumin, the strongest inhibitor, and CPV-2 NS1 endonuclease by molecular docking was -6.4 kcal/mol. Curcumin inhibited CPV-2 NS1 endonuclease via numerous hydrophobic interactions and two hydrogen bonds with Lys97 and Pro111 in the allosteric site. These results suggest that adding curcuminoids, linoleic acid, tannic acid, α-tocopherol, extracted turmeric, sesame cake, and yerba to the diet could prevent CPV-2 infection.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.212-230
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• 2001

Recent advances in recombinant DNA technology have resulted in development of many new protein drugs. Due to the unique properties of protein druges, they have to be delivered by parenteral injection Although delivery of protein drugs by other routes, such as pulmonary and nasal routes, has shown some promises, to date most protein drugs are administered by par-enteral routs. For long-term delivery of protein drugs by parenteral administration, they have been formulated into biodegradable microspheres. A number of microencapsulation methods have been developed, and the currently used microencapsulation methods are reviewed here, The microen-capsulation methods have been divided based on the method used. They are: solvent evapora-tion/extraction; phase separation (coacervation);spray drying; ionotropic gelation/polyelectrolyte complexation; interfacial polyumerization and supercritical fluid precipitation. Each method is de-scribed fro its applications, advantages, and limitations.

• Microbiology and Biotechnology Letters
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• v.25 no.5
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• pp.464-467
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• 1997

A shuttle vector, pSHvec, was constructed for Lactobacillus casei (L. casei) YIT 9018 and JM1O9 by recombinant DNA technology. This vector contained the $\beta$-lactamase II gene from Bacillus cereus as a selection marker and replication origins for both Gram(+) and Gram(-) strains. It could transform the wild type L. casei YIT 9018 as well as E. coli JM109 and transformed cells were selected based on antibiotics resistance. The ability of L. casei YIT 9018 for curd formation in 11% skim milk was maintained even after transformation with pSHvec. The vector was stable as long as antibiotics were added to the medium. These results could contribute to the study of lactic acid bacteria for the industrial purpose at a genetic level.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.241-260
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• 1987

The regulatory mechanisms of gene expression in higher plant were not ascertained in detail because the genome size is very large and complex. However, the above-mentioned study is remarkably progressed in parallel with development of DNA recombinant technology and plant vector system. Some research results connected with the mechanisms could be summarized as follows. 1. Many plant genes including chloroplast genes are cloned. 2. The structures of some regulatory regions of gene expression are determined, and it is confirmed that new regulatory units are made by transposable elements. 3. Plant gene expression is regulated not only at transcriptional level but also at translational level. 4. The factors that regulate plant gene expression could be divided as two categorys. One is endogenous elements including the structural change of chromatin during development stage and tissue differentiation. The other is environmental stimulations such as air, water, heat, salts and light. However, some sufficient research-aid fund is essential in order to study the regulatory mechanisms of gene expression more systematically.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.77-84
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• 2009

Using recombinant DNA technology, the vector system containing minimal fragment of a bacterial hemoglobin gene (vgb) was constructed. When this vector was inserted into Escherichia coli, the growth of the host was significantly improved in both viable cell counts and absorbance measurement, compared to that of the wild type strain. In addition, by minimizing the size of bacterial hemoglobin in the vector, the ability of vgb in growth improvement was augmented, due to the reduction of metabolic burden from the maintenance and replication of the plasmid. By using this system, it is expected that the growth of microorganisms can be improved even in the hypoxic condition.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.201-207
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• 2018

Porphyromonas gingivalis is among the major etiological pathogens of chronic periodontitis. The virulence mechanisms of P. gingivalis is yet to be identified as its activity is largely unknown in actual disease process. The purpose of this study is to identify antigens of P. gingivalis expressed only in patients with chronic periodontitis using a unique immunoscreening technique. Change Mediated Antigen Technology (CMAT), an antibody-based screening technique, was used to identify virulence-associated proteins of P. gingivalis that are expressed only during infection stage in patients having chronic periodontitis. Out of 13,000 recombinant clones screened, 22 tested positive for reproducible reactivity with rabbit hyperimmune anti-sera prepared against dental plaque samples acquired from periodontitis patients. The DNA sequences of these 18 genes were determined. CMAT-identified protein antigens of P. gingivalis included proteins involved in energy metabolism and biosynthesis, heme and iron binding, drug resistance, specific enzyme activities, and unknown functions. Further analysis of these genes could result in a novel insight into the virulence mechanisms of P. gingivalis.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.436-439
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• 1989

The chromosomal DNA fragments of thermophilic alkalophilic Bacillus sp, K-17, a potent xylanhydrolyzing bacterium, were ligated to a vector plasmid pBR322 and transformed into Escherichia coli HB101. The plasmid pAX278, isolated from a transformant forming yellow color on the LB agar plate containing 1 mM p-nitrophenyl- $\beta$-xylopyranoside, was found to enable the transformants to produce p-xylosidase. The 5.0 kilobase insert of pAX278 had single sites for EcoRI, PstI, XbaI, and PvuII, and 2 sites for BglII. Biotinylated pAX218 was hybridized to 0.9 kb as well as 5.0 kb fragment from Bacillus sp. K-17 DNA on nitrocellulose filter. pGX718 was constructed by inserting the 5.0 kb HindIII fragment of pGX278 at the HindIII site of pGR71, E. coli and B. subtilis shuttle vector. The enzymatic properties of $\beta$-xylosidase from E. coli HB101 carrying recombinant plasmid were the same those of $\beta$-xylosidase from Bacillus sp. K-17.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.644-648
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• 2005

Dextranase (${\alpha}$-1,6-D-glucan-6-glucanogydrolase:E.C. 3.2.1.11) catalyzes the hydrolysis of ${\alpha}$-(1.6) linkages of dextran. A lsd1 gene encoding an extracellular dextranase was isolated from the genomic DNA of L. starkeyi. The lsd11 gene is a synthetic dextranase (lsd1) after codon optimization for gene expression with Pichia pastoris system. A open reading frame of lsd11 gene was 1827 bp and it was inserted into the pPIC3.5K expression vector. The plasmid linearized by Sac I was integrated into the 5'AOX region of the chromosomal DNA of P. pastoris. The lsd11 gene fragment encoding a mature protein of 608 amino acids with a predicted molecular weight of 70 kDa, was expressed in the methylotrophic yeast P. pastoris by controling the alcohol oxidase-1 (AOX1) promoter. The recombinant lds11 was optimized by using the shake-flask expression and upscaled using fermentation technology. More than 9.8 mg/L of active dextranase was obtained after induction by methanol. The optimum pH of LSD11 was found to be 5.5 and the optimum temperature $28^{\circ}C$.