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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Microbiology and Biotechnology
Journal Basic Information
Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
Editor in Chief :
Volume & Issues
Volume 18, Issue 12 - Dec 2008
Volume 18, Issue 11 - Nov 2008
Volume 18, Issue 10 - Oct 2008
Volume 18, Issue 9 - Sep 2008
Volume 18, Issue 8 - Aug 2008
Volume 18, Issue 7 - Jul 2008
Volume 18, Issue 6 - Jun 2008
Volume 18, Issue 5 - May 2008
Volume 18, Issue 4 - Apr 2008
Volume 18, Issue 3 - Mar 2008
Volume 18, Issue 2 - Feb 2008
Volume 18, Issue 1 - Jan 2008
Selecting the target year
Red to Red - the Marine Bacterium Hahella chejuensis and its Product Prodigiosin for Mitigation of Harmful Algal Blooms
Kim, Doc-Kyu ; Kim, Ji-Hyun F. ; Yim, Joung-Han ; Kwon, Soon-Kyeong ; Lee, Choong-Hwan ; Lee, Hong-Kum ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1621~1629
Harmful algal blooms (HABs), commonly called red tides, are caused by some toxic phytoplanktons, and have made massive economic losses as well as marine environmental disturbances. As an effective and environment-friendly strategy to control HAB outbreaks, biological methods using marine bacteria capable of killing the harmful algae or algicidal extracellular compounds from them have been given attention. A new member of the
-Proteobacteria, Hahella chejuensis KCTC 2396, was originally isolated from the Korean seashore for its ability to secrete industrially useful polysaccharides, and was characterized to produce a red pigment. This pigment later was identified as an alkaloid compound, prodigiosin. During the past several decades, prodigiosin has been extensively studied for its medical potential as immunosuppressants and antitumor agents, owing to its antibiotic and cytotoxic activities. The lytic activity of this marvelous molecule against Cochlodinium polykrikoides cells at very low concentrations (
l ppb) was serendipitously detected, making H. chejuensis a strong candidate among the biological agents for HAB control. This review provides a brief overview of algicidal marine bacteria and their products, and describes in detail the algicidal characteristics, biosynthetic process, and genetic regulation of prodigiosin as a model among the compounds active against red-tide organisms from the biochemical and genetic viewpoints.
Genetic Characterization of Two Putative Toxin-Antitoxin Systems on Cryptic Plasm ids from Bacillus thuringiensis Strain YBT-1520
Liu, Xiaojin ; Zhu, Shufang ; Ye, Weixing ; Ruan, Lifang ; Yu, Ziniu ; Zhao, Changming ; Sun, Ming ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1630~1633
A novel putative toxin-antitoxin segregational stability system named KyAB system was identified in a novel native plasmid pBMB8240 from Bacillus thuringiensis strain YBT-1520, based on sequences homology with other toxin-antitoxin systems, the lethal activity of the KyB putative toxin in Escherichia coli and the stabilizing effect of the kyAB system in Bacillus thuringiensis. Secondarily, the native plasmid pBMB9741 from the same strain was resequenced and the corrected plasmid was named as pBMB7635. Based on sequence homology with the tasAB system and the lethal activity of toxin protein in Escherichia coli, a tasAB-like putative toxin-antitoxin system was identified on pBMB7635.
Screening of Promoters from Metagenomic DNA and Their Use for the Construction of Expression Vectors
Han, Sang-Soo ; Lee, Jin-Young ; Kim, Won-Ho ; Shin, Hyun-Jae ; Kim, Geun-Joong ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1634~1640
This study was focused on the screening of valuable genetic resources, such as promoters from metagenome, and describes a promoter trapping system with a bidirectional probe concept, which can select promoters or operons from various biological resources including metagenomic DNA. A pair of reporters, GFP and DsRed, facing the opposite direction without promoters, is an effective system that can function regardless of the direction of inserted promoters. The feasibility of this system was tested for the isolation of constitutively expressed promoters in E. coli from a soil metagenome, resulting in a potential pool of various promoters for practical application. The analyses of structural organization of the trapped genes demonstrated that constitutively expressible promoters in E. coli were broadly distributed within the metagenome, and suggested that some promoters were useful for the construction of expression vectors. Based on these observations, three constitutive promoters were employed in the expression vector system and their potentials for practical application were evaluated in terms of expression level, protein solubility, and effects on host growth.
Inhibitory Effect of Amygdalin on Lipopolysaccharide-Inducible TNF-
mRNA Expression and Carrageenan-Induced Rat Arthritis
Hwang, Hye-Jeong ; Lee, Hye-Jung ; Kim, Chang-Ju ; Shim, In-Sop ; Hahm, Dae-Hyun ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1641~1647
Amygdalin is a cyanogenic glycoside plant compound found in the seeds of rosaceous stone fruits. We evaluated the anti-inflammatory and analgesic activities of amygdalin, using an in vitro lipopolysaccharide (LPS)-induced cell line and a rat model with carrageenan-induced ankle arthritis. One mM amygdalin significantly inhibited the expression of TNF-
mRNAs in LPS-treated RAW 264.7 cells. Amygdalin (0.005, 0.05, and 0.1 mg/kg) was intramuscularly injected immediately after the induction of carrageenan-induced arthritic pain in rats, and the anti-arthritic effect of amygdalin was assessed by measuring the weight distribution ratio of the bearing forces of both feet and the ankle circumference, and by analyzing the expression levels of three molecular markers of pain and inflammation (c-Fos, TNF-
, and IL-l
) in the spinal cord. The hyperalgesia of the arthritic ankle was alleviated most significantly by the injection of 0.005 mg/kg amygdalin. At this dosage, the expressions of c-Fos, TNF-
, and IL-l
in the spinal cord were significantly inhibited. However, at dosage greater than 0.005 mg/kg, the pain-relieving effect of amygdalin was not observed. Thus, amygdalin treatment effectively alleviated responses to LPS-treatment in RAW 264.7 cells and carrageenan-induced arthritis in rats, and may serve as an analgesic for relieving inflammatory pain.
Increased Yield of High-Purity and Active Tetrameric Recombinant Human EC-SOD by Solid Phase Refolding
Ryu, Kang ; Kim, Young-Hoon ; Kim, Young-Hwa ; Lee, Joon-Seok ; Jeon, Byeong-Wook ; Kim, Tae-Yoon ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1648~1654
Superoxide dismutase (SOD) removes damaging reactive oxygen species from the cellular environment by catalyzing the dismutation of two superoxide radicals to hydrogen peroxide and oxygen. Extracellular superoxide dismutase (EC-SOD) is a tetramer and is present in the extracellular space and to a lesser extent in the extracellular fluids. Increasing therapeutic applications for recombinant human extracellular superoxide dismutase (rEC-SOD) has broadened interest in optimizing methods for its purification, with a native conformation of tetramer. We describe a solid phase refolding procedure that combines immobilized metal affinity chromatography (IMAC) and gel filtration chromatography in the purification of rEC-SOD from Escherichia coli. The purified rEC-SOD tetramer from the
-column chromatography is refolded in Tris buffer. This method yields greater than 90% of the tetramer form. Greater than 99% purity is achieved with further purification over a Superose 12PC 3.2/30 column to obtain the tetramer and specific activities as determined via DCFHDA assay. The improved yield of rEC-SOD in a simple chromatographic purification procedure promises to enhance the development and therapeutic application of this biologically potent molecule.
Isolation and Structure Determination of a Proteasome Inhibitory Metabolite from a Culture of Scytonema hofmanni
Shim, Sang-Hee ; Chlipala, George ; Orjala, Jimmy ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1655~1658
Cyanobacteria, blue-green algae, are a rich source of bioactive secondary metabolites with many potential applications. The ubiquitin-proteasome proteolytic system plays an important role in selective protein degradation and regulates cellular events including apoptosis. Cancer cells are more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. Thus, proteasome inhibitors can be potential anticancer agents. Cyanobacteria have been shown to be a rich source of highly effective inhibitors of proteases. A proteasome inhibitor was screened from an extract of the culture of Scytonema hofmanni on the basis of its inhibitory activity, which led to the isolation of nostodione A with an
value of 50
. Its structure was determined by spectroscopic methods such as
-NMR and ESI-MS spectral analyses.
Identification of an ISR-Related Metabolite Produced by Pseudomonas chlororaphis O6 against the Wildfire Pathogen Pseudomonas syringae pv. tabaci in Tobacco
Park, Myung-Ryeol ; Kim, Young-Cheol ; Park, Ju-Yeon ; Han, Song-Hee ; Kim, Kil-Yong ; Lee, Sun-Woo ; Kim, In-Seon ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1659~1662
Pseudomonas chlororaphis O6 exhibits induced systemic resistance (ISR) against P. syringae pv. tabaci in tobacco. To identify one of the ISR metabolites, O6 cultures were extracted with organic solvents, and the organic extracts were subjected to column chromatography followed by spectroscopy analyses. The ISR bioassay-guided fractionation was carried out for isolation of the metabolite. High-resolution mass spectrometric analysis of the metabolite found
with an exact mass of 179.0582. LC/MS analysis in positive mode showed an
peak at m/z 180. Nuclear magnetic resonance (
) analyses identified all protons and carbons of the metabolite. Based on the spectroscopy data, the metabolite was identified as 4-(aminocarbonyl) phenylacetate (4-ACPA). 4-ACPA applied at 68.0 mM exhibited ISR activity at a level similar to 1.0 mM salicylic acid. This is the first report to identify an ISR metabolite produced by P. chlororaphis O6 against the wildfire pathogen P. syringae pv. tabaci in tobacco.
Penicillium griseofulvum F1959, High-Production Strain of Pyripyropene A, Specific Inhibitor of Acyl-CoA: Cholesterol Acyltransferase 2
Choi, Jung-Ho ; Rho, Mun-Chual ; Lee, Seung-Woong ; Choi, Ji-Na ; Lee, Hee-Jeong ; Bae, Kyung-Sook ; Kim, Koan-Hoi ; Kim, Young-Kook ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1663~1665
Acyl-coenzyme A: cholesterol acyltransferase (ACAT) catalyzes cholesterol esterification and plays an important role in the intestinal absorption of cholesterol, hepatic production of lipoproteins, and accumulation of cholesteryl ester within cells. During the course of screening to find ACAT inhibitors from microbial sources, the present authors isolated pyripyropene A from Penicillium griseofulvum F1959. Pyripyropene A, an ACAT2-specific inhibitor, has already been produced from Aspergillus fumigatus. Yet, Aspergillus fumigatus is a pathogen and only produces a limited amount of pyripyropene A, making the isolation of pyripyropene A troublesome. In contrast, Penicillium griseofulvum F1959 was found to produce approximately 28 times more pyripyropene A than Aspergillus fumigatus, plus this report also describes the ideal conditions for the production of pyripyropene A by Penicillium griseofulvum F1959 and its subsequent purification.
Mite-Control Activities of Active Constituents Isolated from Pelargonium graveolens Against House Dust Mites
Jeon, Ju-Hyun ; Kim, Hyung-Wook ; Kim, Min-Gi ; Lee, Hoi-Seon ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1666~1671
The mite-control activities of materials obtained from Pelargonium graveolens oil against Dermatophagoides farinae and D. pteronyssinus were examined using an impregnated fabric disk bioassay and were compared with those shown by commercial benzyl benzoate and N,N-diethyl-m-toluamide (DEET). Purification of the biologically active constituents from P. graveolens oil was done by silica gel chromatography and high performance liquid chromatography. The structures of the active components were analyzed by EI/MS,
COSY-NMR, and DEPT-NMR spectra, and were identified as geraniol (
, MW 154.25, trans-3,7-dimethyl-2,6-octadien-l-ol) and
, MW 156.27, 3,7-dimethyl-6-octen-l-o1). Based on the
values, the most toxic compound was geraniol (0.26
), followed by
), benzyl benzoate (10.03
), and DEET (37.12
) against D. farillae. In the case of D. pteronyssinus, geraniol (0.28
) was the most toxic, followed by
), benzyl benzoate (9.58
), and DEET (18.23
). These results suggest that D. farinae and D. pteronyssinus may be controlled more effectively by the application of geraniol and
-citronellol than benzyl benzoate and DEET. Furthermore, geraniol and
-citronellol isolated from P. graveolens could be useful for managing populations of D. farinae and D. pterollyssinus.
Expression, Purification, and Characterization of Iron-Sulfur Cluster Assembly Regulator IscR from Acidithiobacillus ferrooxidans
Zeng, Jia ; Zhang, Ke ; Liu, Jianshe ; Qiu, Guanzhou ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1672~1677
IscR (iron-sulfur cluster regulator) has been reported to be a repressor of the iscRSUA operon, and in vitro transcription reactions have revealed that IscR has a repressive effect on the iscR promoter in the case of [
] cluster loading. In the present study, the iscR gene from A. ferrooxidans ATCC 23270 was cloned and successfully expressed in Escherichia coli, and then purified by one-step affinity chromatography to homogeneity. The molecular mass of the IscR was 18 kDa by SDS-PAGE. The optical and EPR spectra results for the recombinant IscR confirmed that an iron-sulfur cluster was correctly inserted into the active site of the protein. However, no [
] cluster was assembled in apoIscR with ferrous iron and sulfide in vitro. Therefore, the [
] cluster assembly in IscR in vivo would appear to require scaffold proteins and follow the Isc "AUS" pathway.
Diversity Analysis of Lactic Acid Bacteria in Takju, Korean Rice Wine
Jin, Jianbo ; Kim, So-Young ; Jin, Qing ; Eom, Hyun-Ju ; Han, Nam-Soo ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1678~1682
To investigate lactic acid bacterial population in Korean traditional rice wines, biotyping was performed using cell morphology and whole-cell protein pattern analysis by SDS-PAGE, and then the isolates were identified by 16S rRNA sequencing analysis. Based on the morphological characteristics, 103 LAB isolates were detected in wine samples, characterized by whole-cell protein pattern analysis, and they were then divided into 18 patterns. By 16S rRNA gene sequencing, the isolates were identified as Lactobacillus paracasei, Lb. arizonensis, Lb. plantarum, Lb. harbinensis, Lb. parabuchneri, Lb. brevis, and Lb. hilgardii when listed by their frequency of occurrence. It was found that the difference in bacterial diversity between rice and grape wines depends on the raw materials, especially the com position of starch and glucose.
Antiinflammatory Effect of Lactic Acid Bacteria: Inhibition of Cyclooxygenase-2 by Suppressing Nuclear Factor-
in Raw264.7 Macrophage Cells
Lee, Jeong-Min ; Hwang, Kwon-Tack ; Jun, Woo-Jin ; Park, Chang-Soo ; Lee, Myung-Yul ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1683~1688
Lactobacillus casei 3260 (L. casei 3260) was evaluated in relation to the inflammatory response mediated by lipopolysaccharide (LPS)-induced nuclear factor-
) and cyclooxygenase-2 (COX-2) expression in Raw264.7 macrophage cells. The treatment of Raw264.7 cells with L. casei 3260 significantly inhibited the secretion of tumor necrosis factor-
) and prostaglandins
, followed by suppression of COX-2. To clarify the molecular mechanism, the inhibitory effect of L. casei 3260 on the NF-
signaling pathway was examined based on the luciferase reporter activity. Although the treatment of Raw264.7 cells with L. casei 3260 did not affect the transcriptional activity of NF-
, it did inhibit NF-
activation, as determined by the cytosolic p65 release and degradation of I-
. Therefore, these findings suggest that the suppression of COX-2 through inhibiting the NF-
activation by LPS may be associated with the antiinflammatory effects of L. casei 3260 on Raw264.7 cells.
Development of Liposome Immunoassay for Salmonella spp. using Immunomagnetic Separation and Immunoliposome
Shin, Jung-Hee ; Kim, Myung-Hee ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1689~1694
The ability to detect Salmonella spp. is essential in the prevention of foodborne illness. This study examined a Salmonella spp. detection method involving the application of immunomagnetic separation and immunoliposomes (IMS/IL) encapsulating sulforhodamine B (SRB), a fluorescent dye. A quantitative assay was conducted by measuring the fluorescence intensity of SRB that was produced from an immunomagnetic bead-Salmonella spp.-immunoliposome complex. The results indicated detection limits of
CFU/ml for Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterka subsp. enterka serovar Typhimurium (S. Typhimurium), respectivley. The signal/noise ratio was improved by using 4% skim milk as a wash solution rather than 2% BSA. In addition, higher fluorescence intensity was obtained by increasing the liposome size. Compared with the conventional plating method, which takes 3-4 days for the isolation and identification of Salmonella spp., the total assay time of to h only including 6 h of culture enrichment was necessary for the Salmonella detection by IMS/IL. These results indicate that the IMS/ IL has great potential as an alternative rapid method for Salmonella detection.
Development of Surface Plasmon Resonance Immunosensor through Metal Ion Affinity and Mixed Self-Assembled Monolayer
Lee, Si-Ra ; Sim, Sang-Jun ; Park, Chul-Hwan ; Gu, Man-Bock ; Hwang, Un-Yeon ; Yi, Jong-Heop ; Oh, Byung-Keun ; Lee, Jin-Won ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1695~1700
An immunosensor based on surface plasmon resonance (SPR) with enhanced performance was developed through a mixed self-assembled monolayer. A mixture of 16-mercaptohexadecanic acid (16-MHA) and 1-undecanethiol with various molar ratios was self-assembled on gold (Au) surface and the carboxylic acid groups of 16-MHA were then coordinated to Zn ions by exposing the substrate to an ethanolic solution of
. The antibody was immobilized on the SPR surface by exposing the functionalized substrate to the desired solution of antibody in phosphate-buffered saline (PBS) molecules. The film formation in series was confirmed by SPR and atomic force microscopy (AFM). The functionalized surface was applied to develop an SPR immunosensor for detecting human serum albumin (HSA) and the estimated detection limit (DL) was 4.27 nM. The limit value concentration can be well measured between ill and healthy conditions.
Dechlorination of Individual Congeners in Aroclor 1248 as Enhanced by Chlorobenzoates, Chlorophenols, and Chlorobenzenes
Kim, Jong-Seol ; Cho, Young-Cheol ; Frohnhoefer, Robert C. ; Rhee, G-Yull ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1701~1708
Previous investigations showed that three classes of haloaromatic compounds (HACs; chlorobenzoates, chlorophenols, and chlorobenzenes) enhanced the reductive dechlorination of Aroclor 1248, judging from the overall extent of reduction in CI atoms on the biphenyl. In the present study, we further investigated the kind of polychlorinated biphenyl (PCB) congeners involved in the enhanced dechlorination by four isomers belonging to each class (2,3-, 2,5-, 2,3,5-, and 2,4,6-chlorobenzoates; 2,3-, 3,4-, 2,5-, and 2,3,6-chlorophenols; and 1,2-, 1,2,3-, 1,2,4-, and penta-chlorobenzenes). Although the PCB congeners involved in the enhanced dechlorination varied with the HACs, the enhancement primarily involved para-dechlorination of the same congeners (2,3,4'-, 2,3,4,2'-plus 2,3,6,4'-, 2,5,3',4'- plus 2,4,5,2',6'-, and 2,3,6,2',4'-chlorobiphenyls), regardless of the HACs. These congeners are known to have low threshold concentrations for dechlorination. To a lesser extent, the enhancement also involved meta dechlorination of certain congeners with high threshold concentrations. There was no or less accumulation of 2,4,4'- and 2,5,4'-chlorobiphenyls as final products under HAC amendment. Although the dechlorination products varied, the accumulation of ortho-substituted congeners, 2-, 2,2'-, and 2,6-chlorobiphenyls, was significantly higher with the HACs, indicating a more complete dechlorination of the highly chlorinated congeners. Therefore, the present results suggest that the enhanced dechlorination under HAC enrichment is carried out through multiple pathways, some of which may be universal, regardless of the kind of HACs, whereas others may be HAC-specific.
Characterization of Interaction Between Porcine Reproductive and Respiratory Syndrome Virus and Porcine Dendritic Cells
Park, Jie-Yeun ; Kim, Hyun-Soo ; Seo, Sang-Heui ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1709~1716
The porcine reproductive and respiratory syndrome Virus (PRRSV) is an infectious disease that causes abortions and respiratory disorders in swine. In this study, the interaction between PRRSV and porcine dendritic cells generated from
monocytes in the presence of GM-CSF and IL-4 was examined. As a result, it was shown that immature and mature dendritic cells can be productively infected with PRRSV. When the expression of surface MHC molecules on infected dendritic cells was determined, MHC classes I and II were found to be downregulated when compared with un infected dendritic cells. With the exception of the IL-4 and IFN-
cytokines, the induction of the IL-10, IL-12, and TNF-
cytokines all increased in dendritic cells infected with PRRSV. A mixed lymphocyte reaction showed that peripheral blood mononuclear cells cocultured with PRRSV-infected dendritic cells were less stimulated than peripheral blood mononuclear cells cocultured with dendritic cells treated with PBS, LPS, or UV-inactivated PRRSV. Therefore, these results suggest that PRRSV would appear to modulate the immune stimulatory function of porcine dendritic cells.
Detection of Antibodies Against SARS-Coronavirus Using Recombinant Truncated Nucleocapsid Proteins by ELISA
Lee, Hyun-Kyoung ; Lee, Byoung-Hee ; Dutta, Noton Kumar ; Seok, Seung-Hyeok ; Baek, Min-Won ; Lee, Hui-Young ; Kim, Dong-Jae ; Na, Yi-Rang ; Noh, Kyoung-Jin ; Park, Sung-Hoon ; Kariwa, Hiroaki ; Nakauche, Mina ; Mai, Le Quynh ; Heo, Suk-Jin ; Park, Jae-Hak ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1717~1721
Severe acute respiratory syndrome (SARS) is a life-threatening emerging respiratory disease caused by the coronavirus, SARS-CoV. The nucleocapsid (N) protein of SARS-CoV is highly antigenic and may be a suitable candidate for diagnostic applications. We constructed truncated recombinant N proteins (N1 [1-422 aa], N2 [1-109 aa], and N3 [110-422 aa]) and determined their antigenicity by Western blotting using convalescent SARS serum. The recombinants containing N1 and N3 reacted with convalescent SARS serum in Western blotting. However, the recombinant with N2 did not. In ELISA using N1 or N3 as the antigens, positive results were observed in 10 of to (100%) SARS-CoV-positive human sera. None of 50 healthy sera gave positive results in either assay. These data indicate that the ELISA using N1 or N3 has high sensitivity and specificity. These results suggest that the middle or C-terminal region of the SARS N protein is important for eliciting antibodies against SARS-CoV during the immune response, and ELISA reactions using N1 or N3 may be a valuable tool for SARS diagnosis.
Low Frequency of Precore Mutants in Anti-Hepatitis B e Antigen Positive Subjects with Chronic Hepatitis B Virus Infection in Chennai, Southern India
Shanmugam, Saravanan ; Velu, Vijayakumar ; Nandakumar, Subhadra ; Madhavan, Vidya ; Shanmugasundaram, Uma ; Shankar, Esaki Muthu ; Murugavel, Kailapuri G. ; Balakrishnan, Pachamuthu ; Kumarasamy, Nagalingeswaran ; Solomon, Suniti ; Thyagarajan, Sadras Panchatcharam ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1722~1728
The natural course of chronic hepatitis B (CH-B) virus infection is reportedly variable, and the long-term outcomes in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B infection are distinct from HBeAg-positive chronic hepatitis. However, the molecular virological factors that contribute to the progression of liver disease in the south Indian setting remain largely unclear. We prospectively studied 679 consecutive patients for HBsAg, HBeAg, anti-HBe, and HBV DNA by qualitative PCR. Randomly selected samples were subjected to bidirectional sequencing to reveal core/precore variants. Of the total 679 chronic HBV cases investigated, 23% (154/679) were replicative HBV carriers. Furthermore, amongst the 560 HBV DNA samples analyzed, 26% (146/560) were viremic. Among the 154 HBeAg positive cases, HBV DNA was positive in 118 cases (77%), significantly (p<0.001) higher than the anti-HBe positive (7%) (28/406) cases. Significant increase in liver disease (p<0.01) with ALT enzyme elevation (p<0.001) was observed in both HBe and anti-HBe viremic cases. Interestingly, low frequencies of mutations were seen in the precore region of the HBV strains studied. HBV precore and core promoter variants were less often detected in subjects with "e" negative chronic HBV infection and, therefore, may not have a prognostic role in determining liver disease sequelae in this part of tropical India.
Investigation of the Antifungal Activity and Mechanism of Action of LMWS-Chitosan
Park, Yoon-Kyung ; Kim, Mi-Hyun ; Park, Seong-Cheol ; Cheong, Hyeon-Sook ; Jang, Mi-Kyeong ; Nah, Jae-Woon ; Hahm, Kyung-Soo ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1729~1734
Chitosan, a cationic polysaccharide, has been widely used as a dietary supplement and in a variety of pharmacological and biomedical applications. The antifungal activity and mechanism of action of low molecular weight water-soluble chitosan (LMWS-chitosan) were studied in fungal cells and vesicles containing various compositions of fungal lipids. LMWS-chitosan showed strong antifungal activity against various pathogenic yeasts and hyphae-forming fungi but no hemolytic activity or cytotoxicity against mammalian cells. The degree of calcein leakage was assessed on the basis of lipid composition (PC/CH; 10:1, w/w). Our result showing that LMWS-chitosan interacts with liposomes demonstrated that chitosan induces leakage from zwitterionic lipid vesicles. Confocal microscopy revealed that LMWS-chitosan was located in the plasma membrane. Finally, scanning electron microscopy revealed that LMWS-chitosan causes significant morphological changes on fungal surfaces. Its potent antibiotic activity suggests that LMWS-chitosan is an excellent candidate as a lead compound for the development of novel anti-infective agents.
Isolation and Characterization of PERV-C env from Domestic Pig in Korea
Park, Sung-Han ; Bae, Eun-Hye ; Park, Sang-Min ; Park, Jin-Woo ; Lim, Mi-Suk ; Jung, Yong-Tae ;
Journal of Microbiology and Biotechnology, volume 18, issue 10, 2008, Pages 1735~1740
Clone PERV-C (A3) env was isolated from the genomic DNA of domestic pig (Sus scrofa domesticus) in Korea to investigate the molecular properties of PERV-C. The nucleic acid homologies between the PERV-MSL (type C) reference and the PERV-C(A3) clone was 99% for env, but a single base pair deletion was found in the transmembrane (TM) region of the env open reading frame. To examine the functional characteristics of truncated PERV-C env, we constructed a replication-incompetent retroviral vector by replacing the env gene of the pCL-Eco retrovirus vector with PERV-C env. A retroviral vector bearing PERV-C/A chimeric envelopes was also created to complement the TM defect. Our results indicated that truncated PERV-C env was not infectious in human cells as expected. Interestingly, however, the vector with the PERV-C/A envelope was able to infect 293 cells. This observation suggests that recombination within PERV-C TM could render PERV-C infectious in humans. To further characterize PERV-C/A envelopes, we constructed an infectious molecular clone by using a PCR-based technique. This infectious molecular clone will be useful to examine more specific regions that are critical for human cell tropism.