• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.262-270
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• 2007

Of the twelve lytic bacteriophages recovered from five different fermenting cucumber tanks that were inoculated with Pediococcus sp. LA0281, a lytic phage, ${\phi}ps05$, was characterized in the present study. The plaques were mostly clear and round-shaped on the lawn of starter strain, indicating lytic phage. Overall appearance indicated that it belongs to the Siphoviridae family or Bradley's group B1, with a small isometric head and a flexible noncontractile tail with swollen base plate. The average size was found to be 51.2 nm in head diameter and 11.6 nm wide ${\times}$ 129.6 nm long for the tail. The single-step growth kinetics curve showed that the eclipse and the latent period were 29 min and 34 min, respectively, and an average burst size was calculated to be 12 particles per infective center. The optimum proliferating temperature ($35^{\circ}C$) was slightly lower than that of cell growth ($35\;to\;40^{\circ}C$). The structural proteins revealed by SDS-PAGE consisted of one main protein of 33 kDa and three minor proteins of 85, 58, and 52 kDa. The phage genome was a linear double-stranded DNA without cohesive ends. Based on the single and double digestion patterns obtained by EcoRI, HindIII, and SalI, the physical map was constructed. The overall size of the phage genome was estimated to be 24.1 kb. The present report describes the presence of a lytic phage active against a commercial starter culture Pediococcus sp. LA0281 in cucumber fermentation, and a preliminary study characterizes the phage on bacterial successions in the process of starter-added cucumber fermentation.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.753-760
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• 2007

The diversity of Paenibacillus species was assessed in the rhizospheres of four cultivars of sorghum sown in Cerrado soil amended with two levels of nitrogen fertilizer(12 and 120 kg/ha). Two cultivars(IS 5322-C and IS 6320) demanded the higher amount of nitrogen to grow, whereas the other two(FBS 8701-9 and IPA 1011) did not. Using the DNA extracted from the rhizospheres, a Paenibacillus-specific PCR system based on the RNA polymerase gene(rpoB) was chosen for the molecular analyses. The resulting PCR products were separated into community fingerprints by DGGE and the results showed a clear distinction between cultivars. In addition, clone libraries were generated from the rpoB fragments of two cultivars(IPA 1011 and IS 5322-C) using both fertilization conditions, and 318 selected clones were sequenced. Analyzed sequences were grouped into 14 Paenibacillus species. A greater diversity of Paenibacillus species was observed in cultivar IPA 1011 compared with cultivar IS 5322-C. Moreover, statistical analyses of the sequences showed that the bacterial diversity was more influenced by cultivar type than nitrogen fertilization, corroborating the DGGE results. Thus, the sorghum cultivar type was the overriding determinative factor that influenced the community structures of the Paenibacillus communities in the habitats investigated.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.784-791
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• 2007

The present work aims to use a biofilter technology(aerated submerged filters) for the aerobic transformation at laboratory-scale of olive washing water(OWW) generated in the first steps of olive oil processing, as well as the genetic profiling and identification to the species level of the bacteria involved in the formation of the biofilm, by means of TGGE. Chemical parameters, such as biological oxygen demand at five days($BOD_5$) and chemical oxygen demand(COD), decreased markedly(up to 90 and 85%, respectively) by the biological treatment, and the efficiency of the process was significantly affected by aeration and inlet flow rates. The total polyphenol content of inlet OWW was only moderately reduced(around 50% decrease of the inlet content) after the biofilter treatment, under the conditions tested. Partial 16S rRNA genes were amplified using total DNA extracted from the biofilm and separated by TGGE. Sequences of isolated bands were mostly affiliated to the $\alpha-subclass$ of Proteobacteria, and often branched in the periphery of bacteria] genera commonly present in soil(Rhizobium, Reichenowia, Agrobacterium, and Sphingomonas). The data obtained by the experimentation at laboratory scale provided results that support the suitability of the submerged filter technology for the treatment of olive washing waters with the purpose of its reutilization.

• 한국미생물·생명공학회지
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• 제40권1호
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• pp.17-22
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• 2012

가정에서 제조된 청국장으로부터 lactose를 glucose와 galactose로 가수분해하는 ${\beta}$-galactosidase의 생산균을 분리하였다. 분리균 YB-1105는 형태적 특성, 생화학적 성질 및 16S rRNA 유전자 염기서열에 근거하여 Bacillus licheniformis로 확인되었다. B. licheniformis YB-1105의 배양상등액과 균체파쇄액에서 모두 ${\beta}$-galactosidase 활성이 관찰되었으며 이들은 모두 pH 6.5와 $50^{\circ}C$의 반응조건에서 paranitrophenyl-${\beta}$-D-galactopyranoside의 가수분해 활성이 최대로 나타났다. 그러나 균체파쇄상등액에 비해 배양상등액의 ${\beta}$-galactosidase 활성은 산성 pH와 고온에서 크게 영향을 받았다. 한편 두 분획의 가수분해 활성은 낮은 농도의 galactose에 의해도 급격하게 저해되었으나, glucose와 mannose는 고농도에 의해서는 약하게 저해를 받는 것으로 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1621-1628
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• 2012

The agar-degrading bacterium GNUM-1 was isolated from the brown algal species Sargassum serratifolium, which was obtained from the West Sea of Korea, by using the selective artificial seawater agar plate. The cells were Gram-negative, $0.5-0.6{\mu}m$ wide and $2.0-2.5{\mu}m$ long curved rods with a single polar flagellum, forming nonpigmented, circular, smooth colonies. Cells grew at $20^{\circ}C-37^{\circ}C$, between pH 5.0 and 9.0, and at 1-10% (w/v) NaCl. The DNA G+C content of the GNUM-1 strain was 45.5 mol%. The 16S rRNA sequence of the GNUM-1 was very similar to those of Alteromonas stellipolaris LMG 21861 (99.86% sequence homology) and Alteromonas addita $R10SW13^T$(99.64% sequence homology), which led us to assign it to the genus Alteromonas. It showed positive activities for agarase, amylase, gelatinase, alkaline phosphatase, esterase (C8), lipase (C14), leucine arylamidase, valine arylamidase, ${\alpha}$-chymotrypsin, acid phosphatase, naphthol-AS-BI-phosphohydrolase, ${\alpha}$-galactosidase, ${\beta}$-galactosidase, ${\beta}$-glucosidase, catalase, and urease. It can utilize citrate, malic acid, and trisodium citrate. The major fatty acids were summed feature 3 (21.5%, comprising $C_{16:1}{\omega}7c/iso-C_{15:0}$ 2-OH) and C16:0 (15.04%). On the basis of the variations in many biochemical characteristics, GNUM-1 was considered as unique and thus was named Alteromonas sp. GNUM-1. It produced the highest agarase activity in modified ASW medium containing 0.4% sucrose, but lower activity in rich media despite superior growth, implying that agarase production is tightly regulated and repressed in a rich nutrient condition. The 30 kDa protein with agarase activity was identified by zymography, and this report serves as the very first account of such a protein in the genus Alteromonas.

• 한국환경농학회지
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• 제30권3호
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• pp.346-356
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• 2011

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and ${\beta}$-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and ${\beta}$-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% $Na_2HPO_4$, 0.07% $KH_2PO_4$, 0.0001% $MgSO_4$, and 0.0001% $MnSO_4$ at $30^{\circ}C$. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi. CONCLUSION(S): This study demonstrated the multiantifungal enzyme production by Streptomyces sp. AM50 for the biological control of major plant pathogens. Further studies will investigate the synergistic effect, to the growth regulations by biogenic amines and antifungal enzyme gene promoter.

• International Journal of Industrial Entomology and Biomaterials
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• 제36권2호
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• pp.25-30
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• 2018

The larvae of Hermetia. illucens have a high probability of coming into contact with microorganisms such as bacteria and fungi. Therefore, the survival of H. illucens is primarily the protection of their own against microbial infection. This effect depends on the development of the innate immune system. Antimicrobial Peptides (AMPs) exhibit antimicrobial activity against other bacterial strains and can provide important data to understand the basis of the innate immunity of H. illucens. In this study, we injected larvae with Enterococcus. faecalis (gram-positive bacteria) and Serratia. marcescens as (gram-negative bacteria) to test the hypothesis that H. illucens is protected from infection by its immune-related gene expression repertoire. To identify the inducible immune-related genes, we performed and cataloged the transcriptomes by RNA-Seq analysis. We compared the transcriptomes of whole larvae and obtained a DNA fragment of 465 bp including the poly (A) tail by RACE as a novel H. illucens immune-related gene against bacteria. A novel target mRNA expression was higher in immunized larvae with E. faecalis and S. marcescens groups than non-immunized group. We expect our study to provide evidence that the global RNA-Seq approach allowed for the identification of a gene of interest which was further analyzed by quantitative RT-PCR, together with genes chosen from the available literature.

• Food Science and Biotechnology
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• 제17권4호
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• pp.761-765
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• 2008

Bacillus cereus causes two different types of food poisoning syndromes: diarrhea and emesis. The diarrheal syndrome is attributed to various enterotoxins, including nonhemolytic enterotoxin, hemolytic enterotoxin, and enterotoxin-T, whereas the emetic syndrome is caused by the dodecadepsipeptide toxin cereulide. A multiplex polymerase chain reaction (PCR) assay was developed to rapidly detect and identify B. cereus strains. Three primer pairs specific to regions within genes encoding nonhemolytic enterotoxin (nheA), molecular chaperonin (groEL), and cereulide synthetase (ces) were used to identify and differentiate between the enterotoxin-producing and emetic toxin-producing B. cereus strains. The cereulide-producing emetic B. cereus showed 3 PCR products of 325, 405, and 685 bp for the groEL, ces, and nheA genes, respectively, whereas the enterotoxin-producing B. cereus showed 2 PCR products without a ces gene specific DNA fragment. Specific amplifications and differentiations by multiplex PCR assay were obtained using 62 B. cereus strains and 13 strains' of other bacterial species. The detection limit of this assay for enterotoxin-producing strain and emetic toxin-producing strain from pure cultures were $2.4{\times}10^1$ and $6.0{\times}10^2\;CFU/tube$, respectively. These results suggest that our multiplex PCR method may be useful for the rapid detection and differentiation of B. cereus strains in foods.

• 한국식품위생안전성학회:학술대회논문집
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• 한국식품위생안전성학회 1996년도 제11회 학술대회 및 정기총회 - 식품의 위생 안전성에 관한 최근 연구 동향
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• pp.33-33
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• 1996

Interests in the field of rapid methods and automation in microbiology have been growing steadily on an international scale in recent years. International meetings concerned this problem have been held in elsewhere in the world countries since the past twenty years. But, unfortunately in the field of microbial examination in food hygiene, this problem have not yet been developed so much as in the field of clinical microbiology. Today, I would like to introduce you here present aspects of rapid and automation technologies, those which are manly carrying in milk and meats industries. My illustration will be given recent improved technologies using automatic apparatus and instruments along with process of microbial count procedure. Recent direct microbiological counting system (ChemeScan \ulcorner) as real time ultrasensitive analysis created by Cheminex Ltd., France is now most evolutional instrument to provide direct microbial counts, down to one cell, within 30 minutes. The results from these evaluations how a good correlation between the ChemScan system and the standard plate count method. This system will be successful application for not only in the field of pharmacology but also food microbiology. In addition, current identification of microbes by sophisticated instruments suitable for food microbiology, one of which Biology is manual system (BIOLOG\ulcorner), provides reference-level capability at a modes price. For the manual system, the color reactions in the microplate are read by eye and manually keyed into personal computer. Species identification appears on the computer screen within seconds, along with biotype patterns, a list of closely related species, and other useful statistics. In present this is useful application for microbial ecology and epidemiological survey. RiboPrinter system newly produced by DuPont is now focusing among microbiologists in the world, and is one of the biggest microbial characterization system using a DNA-based approach. The technology analyzer is bacterial culture for its genetic fingerprint or riboprint pattern. Finally Bio-cellTracer system for automatic measurement of fungal growth and Fukitori-Maseter, a Surface Hygiene Monitoring Kit by using swabe procedure in food processing environment are briefly illustrated in this presentation.

• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1361-1365
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• 2001

Recombinant immunotoxins are hybrid cytotoxic proteins designed to selectively kill cancer cells. A divalent immunotoxins, [B3(FabH1)-PE38]2, was constructed by recombining Fab domain of B3 antibody as a cell-targeting domain and Pseudo monas exotoxin A (PE) as a cytotoxic domain. Monoclonal antibody, B3, is the murine antibody (IgG1k) directed against Lewis Y-related carbohydrate antigens, which are abundant on the surface of many carcinomas. Fab fragment of this antibody was used in this study with the modified hinge sequence where last two cysteines out of three were mutated to serine. PE is a 66 kDa bacterial toxin that kills eukaryotic cells by inhibiting protein synthesis with ADP ribosylation of ribosomal elongation factor 2 (EF2). Fc region of B3 antibody was substituted with the truncated form of PE (38 kDa, PE38) on DNA level. [B3(FabH1)-PE38]2 was formed by disulfide bond between cysteines in the modified hinge region of B3(FabH1)-PE38. Each polypeptide for recombinant immunotoxins was overexpressed in Escherichia coli and collected as inclusion bodies. Each inclusion body was solubilized and refolded, and cytotoxic effects were measured. Divalent immunotoxins, [B3(FabH1)-PE38]2, had ID50 values of about 10 ng/mL on A431 cell lines and about 4 ng/mL on CRL1739 cell lines. Control immunotoxins, B3(scFv)-PE40, had ID50 values of about 28 ng/mL on A431 cell lines and about 41 ng/mL on CRL1739 cell lines. Divalent immunotoxins, [B3(FabH1)-PE38]2, had higher cytotoxic effects than B3(scFv)-PE40 control immunotoxins.