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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Microbiology and Biotechnology
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Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 22, Issue 12 - Dec 2012
Volume 22, Issue 11 - Nov 2012
Volume 22, Issue 10 - Oct 2012
Volume 22, Issue 9 - Sep 2012
Volume 22, Issue 8 - Aug 2012
Volume 22, Issue 7 - Jul 2012
Volume 22, Issue 6 - Jun 2012
Volume 22, Issue 5 - May 2012
Volume 22, Issue 4 - Apr 2012
Volume 22, Issue 3 - Mar 2012
Volume 22, Issue 2 - Feb 2012
Volume 22, Issue 1 - Jan 2012
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RFLP Analysis of cry1 and cry2 Genes of Bacillus thuringiensis Isolates from India
Patel, Ketan D. ; Ingle, Sanjay S. ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 729~735
DOI : 10.4014/jmb.1111.11046
The PCR-RFLP method has been useful for detection of known genes and identification of novel genes. In the present study, degenerate primers were designed from five groups of cry1 genes for PCR-RFLP analysis. Bacillus thuringiensis (Bt) isolates from different regions were evaluated for PCR amplification of various cry1 genes using newly designed primers and cry2 genes using reported primers. PCR analysis showed an abundance of cry1A genes and especially cry1Ac genes in isolates from all regions. RFLP analysis revealed the presence of multiple cry1A genes in isolates from central and southern regions. Unique digestion patterns of cry1A genes were observed in isolates from each region. Few of the isolates represented a digestion pattern of cry1A genes that did match to any of the known cry1A genes. RFLP analysis suggested an abundance of cry2Ab along with a novel cry2 gene in Bt isolates from different regions of India. Sequence analysis of the novel cry2 gene revealed 95% sequence identity to cry2Ab and cry2Ah genes. Phylogenetic analysis revealed that the novel cry2 gene could have diverged earlier than the other cry2 genes. Our results encourage finding of more diverse cry2 genes in Bt isolates. Rarefaction analysis was used to compare cry1A gene diversity in isolates from different soil types. It showed a higher degree of cry1A gene diversity in isolates from central region. In the present study, we propose the use of novel degenerate primers for cry1 genes and the PCR-RFLP method using a single enzyme to distinguish multiple cry1A and cry2 genes as well as identify novel genes.
Negative Role of wblA in Response to Oxidative Stress in Streptomyces coelicolor
Kim, Jin-Su ; Lee, Han-Na ; Kim, Pil ; Lee, Heung-Shick ; Kim, Eung-Soo ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 736~741
DOI : 10.4014/jmb.1112.12032
In this study, we analyzed the oxidative stress response of wblA (
, SCO3579), which was previously shown to be a global antibiotic down-regulator in Streptomyces coelicolor. Ever since a WblA ortholog named WhcA in Corynebacterium glutamicum was found to play a negative role in the oxidative stress response, S. coelicolor wblA has been proposed to have a similar effect. A wblA-deletion mutant exhibited a less sensitive response to oxidative stress induced by diamide present in solid plate culture. Using real-time RT-PCR analysis, we also compared the transcription levels of oxidative stress-related genes, including sodF, sodF2, sodN, trxB, and trxB2, between S. coelicolor wild type and a wblA-deletion mutant in the presence or absence of oxidative stress. Target genes were expressed higher in the wblA-deletion mutant compared with wild type, both in the absence and presence of oxidative stress. Moreover, expression of these target genes in S. coelicolor wild type was stimulated only in the presence of oxidative stress, suggesting that WblA plays a negative role in the oxidative stress response of S. coelicolor, similar to that of C. glutamicum WhcA, through the transcriptional regulation of oxidative stress-related genes.
The Heavy Metal Tolerant Soil Bacterium Achromobacter sp. AO22 Contains a Unique Copper Homeostasis Locus and Two mer Operons
Ng, Shee Ping ; Palombo, Enzo A. ; Bhave, Mrinal ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 742~753
DOI : 10.4014/jmb.1111.11042
Copper-containing compounds are introduced into the environment through agricultural chemicals, mining, and metal industries and cause severe detrimental effects on ecosystems. Certain microorganisms exposed to these stressors exhibit molecular mechanisms to maintain intracellular copper homeostasis and avoid toxicity. We have previously reported that the soil bacterial isolate Achromobacter sp. AO22 is multi-heavy metal tolerant and exhibits a mer operon associated with a Tn21 type transposon. The present study reports that AO22 also hosts a unique cop locus encoding copper homeostasis determinants. The putative cop genes were amplified from the strain AO22 using degenerate primers based on reported cop and pco sequences, and a constructed 10,552 base pair contig (GenBank Accession No. GU929214). BLAST analyses of the sequence revealed a unique cop locus of 10 complete open reading frames, designated copSRABGOFCDK, with unusual separation of copCD from copAB. The promoter areas exhibit two putative cop boxes, and copRS appear to be transcribed divergently from other genes. The putative protein CopA may be a copper oxidase involved in export to the periplasm, CopB is likely extracytoplasmic, CopC may be periplasmic, CopD is cytoplasmic/inner membrane, CopF is a P-type ATPase, and CopG, CopO, and CopK are likely copper chaperones. CopA, B, C, and D exhibit several potential copper ligands and CopS and CopR exhibit features of two-component regulatory systems. Sequences flanking indicate the AO22 cop locus may be present within a genomic island. Achromobacter sp. strain AO22 is thus an ideal candidate for understanding copper homeostasis mechanisms and exploiting them for copper biosensor or biosorption systems.
Dinophyceae Fluctuations in Two Alpine Lakes of Contrasting Size During a 10-Year Fortnightly Survey
Trevisan, R. ; Pertile, R. ; Bronamonte, V. ; Dazzo, F.B. ; Squartini, A. ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 754~762
DOI : 10.4014/jmb.1110.10005
Colbricon Superiore and Inferiore are two small adjacent high-mountain lakes located in the Paneveggio Natural Park (Italy) that offer the rare opportunity to study two iso-ecologic water environments differing only by area and volume in a ratio of 2:1 and 3:1, respectively. We took advantage of this setting to investigate phytoplankton dynamics, compare variability and productivity differences between the two basins, and assess size-dependent issues. The phytoplankton group of the Dinophyceae was chosen as the indicator organisms of ecological perturbation owing to their high sensitivity to environmental variations, as well as their acknowledged nature of versatile proxy to report global climatic changes. The study was conducted for over 10 years with fortnightly samplings. Results indicated that (a) the Dinophyceae communities in the smaller lake were significantly more resistant to changes exerted by the fluctuation of lakewater transparency and pH; and (b) the smaller lake sustained a consistently higher production with an average Dinophyceae density 1.73 fold higher than that of the larger lake. The coefficients of variation show that the chemical parameters in the smaller lake display higher time-related fluctuation while being spatially homogeneous and that such conditions correlate with a higher stability of the Dinophyceae assemblage. The use of this setting is also proposed as a model to test relationships between ecosystem production and physical stability.
Colonizing Ability of Pseudomonas fluorescens 2112, Among Collections of 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens spp. in Pea Rhizosphere
Kim, Sang-Dal ; Fuente, Leonardo De La ; Weller, David M. ; Thomashow, Linda S. ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 763~770
DOI : 10.4014/jmb.1112.12039
Pseudomonas fluorescens 2112, isolated in Korea as an indigenous antagonistic bacteria, can produce 2,4-diacetylphloroglucinol (2,4-DAPG) and the siderophore pyoveridin2112 for the control of phytophthora blight of red-pepper. P. fluorescens 2112 was classified into a new genotype C among the 17 genotypes of 2,4-DAPG producers, by phlD restriction fragment length polymorphism (RFLP). The colonizing ability of P. fluorescens 2112 in pea rhizosphere was equal to the well-known pea colonizers, P. fluorescens Q8r1 (genotype D) and MVP1-4 (genotype P), after 6 cycling cultivations for 18 weeks. Four tested 2,4-DAPG-producing Pseudomonas spp. could colonize with about a 96% dominance ratio against total bacteria in pea rhizosphere. The strain P. fluorescens 2112 was as good a colonizer as other Pseudomonas spp. genotypes in pea plant growth-promoting rhizobacteria.
High Level of Bacterial Diversity and Novel Taxa in Continental Shelf Sediment
Hong, Jin-Kyung ; Cho, Jae-Chang ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 771~779
DOI : 10.4014/jmb.1112.12004
The bacterial diversity of the continental shelf sediment in the Yellow Sea was investigated by the cloning and sequencing of PCR-amplified 16S rRNA genes. The majority of the cloned sequences were distinct phylotypes that were novel at the species level. The richness estimator indicated that the sediment sample might harbor up to 32 phylum-level taxa. A large number of low-abundance, phylum-level taxa accounted for most of the observed phylogenetic diversity at our study site, suggesting that these low-abundance taxa might play crucial roles in the shelf sediment ecosystem.
Proteomic Comparison of Gibberella moniliformis in Limited-Nitrogen (Fumonisin-Inducing) and Excess-Nitrogen (Fumonisin-Repressing) Conditions
Choi, Yoon-E ; Butchko, Robert A.E. ; Shim, Won-Bo ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 780~787
DOI : 10.4014/jmb.1111.11044
The maize pathogen Gibberella moniliformis produces fumonisins, a group of mycotoxins associated with several disorders in animals and humans, including cancer. The current focus of our research is to understand the regulatory mechanisms involved in fumonisin biosynthesis. In this study, we employed a proteomics approach to identify novel genes involved in the fumonisin biosynthesis under nitrogen stress. The combination of genome sequence, mutant strains, EST database, microarrays, and proteomics offers an opportunity to advance our understanding of this process. We investigated the response of the G. moniliformis proteome in limited nitrogen (N0, fumonisin-inducing) and excess nitrogen (N+, fumonisin-repressing) conditions by one- and two-dimensional electrophoresis. We selected 11 differentially expressed proteins, six from limited nitrogen conditions and five from excess nitrogen conditions, and determined the sequences by peptide mass fingerprinting and MS/MS spectrophotometry. Subsequently, we identified the EST sequences corresponding to the proteins and studied their expression profiles in different culture conditions. Through the comparative analysis of gene and protein expression data, we identified three candidate genes for functional analysis and our results provided valuable clues regarding the regulatory mechanisms of fumonisin biosynthesis.
Computational Tridimensional Protein Modeling of Cry1Ab19 Toxin from Bacillus thuringiensis BtX-2
Kashyap, S. ; Singh, B.D. ; Amla, D.V. ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 788~792
DOI : 10.4014/jmb.1106.06034
We report the computational structural simulation of the Cry1Ab19 toxin molecule from B. thuringiensis BtX-2 based on the structure of Cry1Aa1 deduced by x-ray diffraction. Validation results showed that 93.5% of modeled residues are folded in a favorable orientation with a total energy Z-score of -8.32, and the constructed model has an RMSD of only
. The major differences in the presented model are longer loop lengths and shortened sheet components. The overall result supports the hierarchical three-domain structural hypothesis of Cry toxins and will help in better understanding the structural variation within the Cry toxin family along with facilitating the design of domain-swapping experiments aimed at improving the toxicity of native toxins.
Isolation and Functional Analysis of spy1 Responsible for Pristinamycin Yield in Streptomyces pristinaespiralis
Jin, Qingchao ; Yin, Huali ; Hong, Xiaowei ; Jin, Zhihua ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 793~799
DOI : 10.4014/jmb.1111.11031
A gene related to high pristinamycin yield in Streptomyces pristinaespiralis was selected by amplified fragment length polymorphism (AFLP) and its functions were investigated by gene disruption. First, a 561 bp polymorphic sequence was acquired by AFLP from high-yield recombinants compared with the S. pristinaespiralis ancestor ATCC25486, indicating that this approach is an effective means of screening for valuable genes responsible for antibiotic yield. Then, a 2,127 bp open reading frame of a gene designated spy1 that overlaps with the above fragment was identified and its structure and biological functions were investigated. In silico analysis of spy1 encoding a deduced 708-amino-acid-long serine/threonine protein kinase showed that it only contains a catalytic domain in the N-terminal region, which is different from some known homologs. Gene inactivation of chromosomal spy1 indicated that it plays a pleiotropic regulatory function in pristinamycin production, with a positive correlation to pristinamycin I biosynthesis and a negative correlation to pristinamycin II biosynthesis.
Antimicrobial Activity of Licochalcone E Against Staphylococcus aureus and Its Impact on the Production of Staphylococcal Alpha-Toxin
Zhou, Tiezhong ; Deng, Xuming ; Qiu, Jiazhang ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 800~805
DOI : 10.4014/jmb.1112.12020
Licochalcone E was firstly isolated from licorice root in 2005, which belongs to the retrochalcone family. Studies on the biological activities of licochalcone E were in the initial stage. In the study, we demonstrated that licochalcone E has potent antimicrobial property against Staphylococcus aureus. Furthermore, via hemolysis, Western blot, and real-time RT-PCR assays, we have shown that subinhibitory concentrations of licochalcone E dose-dependently reduces the production of
-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The data suggest that licochalcone E may deserve further investigation as a potential therapeutic against S. aureus infections, or the structure of licochalcone E may be used as a basis for chemical synthesis of novel anti-S. aureus compounds.
Widdrol Blocks 3T3-L1 Preadipocytes Growth and Differentiation Due to Inhibition of Mitotic Clonal Expansion
Yun, Hee-Jung ; Kim, Jeong-Hwan ; Jeong, Hyun-Young ; Ji, Hyang-Hwa ; Nam, Soo-Wan ; Lee, Eun-Woo ; Kim, Byung-Woo ; Kwon, Hyun-Ju ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 806~813
DOI : 10.4014/jmb.1110.10039
Adipocyte differentiation is strongly associated with obesity, which causes metabolic disorders. In this study, we investigated the inhibitory effects of widdrol on 3T3-L1 preadipocyte growth and differentiation. Widdrol decreased lipid droplet accumulation and down-regulated adipogenic transcription factors such as C/
. Widdrol blocked preadipocyte proliferation and differentiation through the inhibition of mitotic clonal expansion, which was accompanied by the failure of degradation of p21, a cyclin-dependent kinase inhibitor. Cell-cycle analysis clearly indicated that widdrol actively induces cell-cycle arrest at the G1-S phage transition, causing cells to remain in the preadipocyte state. Moreover, widdrol increased p21 expression and inhibited Rb phosphorylation in preadipocyte incubated in a hormone medium. Therefore, these findings clearly suggest that widdrol blocks preadipocyte growth and differentiation through the inhibition of mitotic clonal expansion by p21-and Rb-dependent G1 arrest and can be developed as a potent anti-adipogenic agent for reducing obesity.
Inhibitory Effect of Melanogenesis by 5-Pentyl-2-Furaldehyde Isolated from Clitocybe sp.
Kim, Young-Hee ; Choo, Soo-Jin ; Ryoo, In-Ja ; Kim, Bo-Yeon ; Ahn, Jong-Seog ; Yoo, Ick-Dong ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 814~817
DOI : 10.4014/jmb.1101.01053
In the continued search for melanogenesis inhibitors from microbial metabolites, we found that the culture broth of Clitocybe sp. MKACC 53267 inhibited melanogenesis in B16F10 melanoma cells. The active component was purified by solvent extraction, silica gel chromatography, Sephadex LH-20 column chromatography, and finally by preparative HPLC. Its structure was determined as 5-pentyl-2-furaldehyde on the basis of the UV, NMR, and MS spectroscopic analysis. The 5-pentyl-2-furaldehyde potently inhibited melanogenesis in B16F10 cells with an
value of 8.4
, without cytotoxicity.
Immobilization of Keratinolytic Metalloprotease from Chryseobacterium sp. Strain kr6 on Glutaraldehyde-Activated Chitosan
Silveira, Silvana T. ; Gemelli, Sabrine ; Segalin, Jeferson ; Brandelli, Adriano ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 818~825
DOI : 10.4014/jmb.1111.11048
Keratinases are exciting keratin-degrading enzymes; however, there have been relatively few studies on their immobilization. A keratinolytic protease from Chryseobacterium sp. kr6 was purified and its partial sequence determined using mass spectrometry. No significant homology to other microbial peptides in the NCBI database was observed. Certain parameters for immobilization of the purified keratinase on chitosan beads were investigated. The production of the chitosan beads was optimized using factorial design and surface response techniques. The optimum chitosan bead production for protease immobilization was a 20 g/l chitosan solution in acetic acid [1.5% (v/v)], glutaraldehyde ranging from 34 g to 56 g/l, and an activation time between 6 and 10 h. Under these conditions, above 80% of the enzyme was immobilized on the support. The behavior of the keratinase loading on the chitosan beads surface was well described using the Langmuir model. The maximum capacity of the support (
) and dissociation constant (
) were estimated as 58.8 U/g and 0.245 U/ml, respectively. The thermal stability of the immobilized enzyme was also improved around 2-fold, when compared with that of the free enzyme, after 30 min at
. In addition, the activity of the immobilized enzyme remained at 63.4% after it was reused five times. Thus, the immobilized enzyme exhibited an improved thermal stability and remained active after several uses.
Significantly Enhanced Production of Acarbose in Fed-Batch Fermentation with the Addition of S-Adenosylmethionine
Sun, Li-Hui ; Li, Ming-Gang ; Wang, Yuan-Shan ; Zheng, Yu-Guo ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 826~831
DOI : 10.4014/jmb.1111.11047
Acarbose, a pseudo-oligosaccharide, is widely used clinically in therapies for non-insulin-dependent diabetes. In the present study, S-adenosylmethionine (SAM) was added to selected media in order to investigate its effect on acarbose fermentation by Actinoplanes utahensis ZJB-08196. Acarbose titer was seen to increase markedly when concentrations of SAM were added over a period of time. The effects of glucose and maltose on the production of acarbose were investigated in both batch and fed-batch fermentation. Optimal acarbose production was observed at relatively low glucose levels and high maltose levels. Based on these results, a further fed-batch experiment was designed so as to enhance the production of acarbose. Fed-batch fermentation was carried out at an initial glucose level of 10 g/l and an initial maltose level of 60 g/l. Then, 12 h post inoculation, 100
SAM was added. In addition, 8 g/l of glucose was added every 24 h, and 20 g/l of maltose was added at 96 h. By way of this novel feeding strategy, the maximum titer of acarbose achieved was 6,113 mg/l at 192 h. To our knowledge, the production level of acarbose achieved in this study is the highest ever reported.
Oxidative Potential of Some Endophytic Fungi Using 1-Indanone as Substrate
Fill, Taicia Pacheco ; Silva, Jose Vinicius Da ; Oliveira, Kleber Thiago De ; Silva, Bianca Ferreira Da ; Rodrigues-Fo, Edson ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 832~837
DOI : 10.4014/jmb.1112.12014
The oxidative potential of the fungus Penicillium brasilianum, a strain isolated as endophytic from a Meliaceae plant (Melia azedarach), was investigated using 1-indanone as substrate to track the production of monooxygenases. The fungus produced the dihydrocoumarin from 1-indanone with the classical Baeyer-Villiger reaction regiochemistry, and (-)-(R)-3-hydroxy-1-indanone with 78% ee. Minor compounds that had resulted from lipase and SAM activities were also detected. The biotransformation procedures were also applied using a collection of Penicillium and Aspergillus fungi obtained from M. azedarach and Murraya paniculata. The results showed that Baeyer-Villiger were mostly active in fungi isolated from M. azedarach. Almost all fungi tested produced 3-hydroxy-1-indanone.
Development of Fecal Microbial Enzyme Mix for Mutagenicity Assay of Natural Products
Yeo, Hee-Kyung ; Hyun, Yang-Jin ; Jang, Se-Eun ; Han, Myung-Joo ; Lee, Yong-Sup ; Kim, Dong-Hyun ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 838~848
DOI : 10.4014/jmb.1112.12028
Orally administered herbal glycosides are metabolized to their hydrophobic compounds by intestinal microflora in the intestine of animals and human, not liver enzymes, and absorbed from the intestine to the blood. Of these metabolites, some, such as quercetin and kaempherol, are mutagenic. The fecal bacterial enzyme fraction (fecalase) of human or animals has been used for measuring the mutagenicity of dietary glycosides. However, the fecalase activity between individuals is significantly different and its preparation is laborious and odious. Therefore, we developed a fecal microbial enzyme mix (FM) usable in the Ames test to remediate the fluctuated reaction system activating natural glycosides to mutagens. We selected, cultured, and mixed 4 bacteria highly producing glycosidase activities based on a cell-free extract of feces (fecalase) from 100 healthy Korean volunteers. When the mutagenicities of rutin and methanol extract of the flos of Sophora japonica L. (SFME), of which the major constituent is rutin, towards Salmonella typhimurium strains TA 98, 100, 102, 1,535, and 1,537 were tested using FM and/or S9 mix, these agents were potently mutagenic. These mutagenicities using FM were not significantly different compared with those using Korean fecalase. SFME and rutin were potently mutagenic in the test when these were treated with fecalase or FM in the presence of S9 mix, followed by those treated with S9 mix alone and those with fecalase or FM. Freeze-dried FM was more stable in storage than fecalase. Based on these findings, FM could be usable instead of human fecalase in the Ames test.
Rapid Detection of Cadmium-Resistant Plant Growth Promotory Rhizobacteria: A Perspective of ELISA and QCM-Based Immunosensor
Agrawal, Ruchi ; Satlewal, Alok ; Chaudhary, Manav ; Verma, Amit ; Singh, Rachna ; Verma, A.K. ; Kumar, Rajesh ; Singh, K.P. ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 849~855
DOI : 10.4014/jmb.1108.08055
Plant growth-promoting rhizobacteria (PGPR) pseudomonads have a large number of lipopolysaccharides on the cell surface, which induces immune responses. Cd-resistant PGPR prevalent at the Cd-affected sites under biophytostabilization was monitored. Transmissiom electron microscopy was used to the study the behavior of tolerance of PGPR to cadmium level and its effect on pseudomonad strains (Z9, S2, KNP2, CRPF, and NBRI). An immunosensor was developed by immobilizing antibody (anti-Z9 or anti-S2) against selected PGPR on a piezoelectric quartz crystal microbalance (QCM). Immunosensors were found to supplement the inherent specificity of antigen-antibody reactions with the high sensitivity of a physical transducer. On comparison of the efficiency of detection with ELISA, the spectrophotometric technique, the developed immunosensor was found to be more sensitive, fast, and reliable even after regeneration for several times. Thus, the immunosensor may be used for future detection of PGPR strains after automation of the screening process.
Construction and Preliminary Immunobiological Characterization of a Novel, Non-Reverting, Intranasal Live Attenuated Whooping Cough Vaccine Candidate
Cornford-Nairns, R. ; Daggard, G. ; Mukkur, T. ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 856~865
DOI : 10.4014/jmb.1108.08003
We describe the construction and immunobiological properties of a novel whooping cough vaccine candidate, in which the aroQ gene, encoding 3-dehydroquinase, was deleted by insertional inactivation using the kanamycin resistance gene cassette and allelic exchange using a Bordetella suicide vector. The aroQ B. pertussis mutant required supplementation of media to grow but failed to grow on an unsupplemented medium. The aroQ B. pertussis mutant was undetectable in the trachea and lungs of mice at days 6 and 12 post-infection, respectively. Antigen-specific antibody isotypes IgG1 and IgG2a, were produced, and cell-mediated immunity [CMI], using interleukin-2 and interferon-gamma as indirect indicators, was induced in mice vaccinated with the aroQ B. pertussis vaccine candidate, which were substantially enhanced upon second exposure to virulent B. pertussis. Interleukin-12 was also produced in the aroQ B. pertussis-vaccinated mice. On the other hand, neither IgG2a nor CMI-indicator cytokines were produced in DTaP-vaccinated mice, although the CMI-indicator cytokines became detectable post-challenge with virulent B. pertussis. Intranasal immunization with one dose of the aroQ B. pertussis mutant protected vaccinated mice against an intranasal challenge infection, with no pathogen being detected in the lungs of immunized mice by day 7 post-challenge. B. pertussis aroQ thus constitutes a safe, non-reverting, metabolite-deficient vaccine candidate that induces both humoral and cell-mediated immune responses with potential for use as a single-dose vaccine in adolescents and adults, in the first instance, with a view to disrupting the transmission cycle of whooping cough to infants and the community.
Transfection Property of a New Cholesterol-Based Cationic Lipid Containing Tri-2-Hydroxyethylamine as Gene Delivery Vehicle
Kim, Bieong-Kil ; Doh, Kyung-Oh ; Hwang, Guen-Bae ; Seu, Young-Bae ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 866~871
DOI : 10.4014/jmb.1111.11010
A novel cholesterol-based cationic lipid containing a tri-2-hydroxyethylamine head group and ether linker (Chol-THEA) was synthesized and examined as a potent gene delivery vehicle. In the preparation of cationic liposome, the addition of DOPE as helper lipid significantly increased the transfection efficiency. To find the optimum transfection efficiency, we screened various weight ratios of DOPE and liposome/DNA (N/P). The best transfection efficiency was found at the Chol-THEA:DOPE weight ratio of 1:1 and N/P weight ratio of 10~15. Most of the plasmid DNA was retarded by this liposome at the optimum N/P weight ratio of 10. The transfection efficiency of Chol-THEA liposome was compared with DOTAP, Lipofectamine, and DMRIE-C using the luciferase assay and GFP expression. Chol-THEA liposome with low toxicity had better or similar potency of gene delivery compared with commercial liposomes in COS-7, Huh-7, and MCF-7 cells. Therefore, Chol-THEA could be a useful non-viral vector for gene delivery.
Inhibition of Klebsiella pneumoniae ATCC 13883 Cells by Hexane Extract of Halimeda discoidea (Decaisne) and the Identification of Its Potential Bioactive Compounds
Supardy, Nor Afifah ; Ibrahim, Darah ; Sulaiman, Shaida Fariza ; Zakaria, Nurul Aili ;
Journal of Microbiology and Biotechnology, volume 22, issue 6, 2012, Pages 872~881
DOI : 10.4014/jmb.1111.11053
The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9
, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GC-MS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.