• Korean Journal of Microbiology
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• v.53 no.4
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• pp.337-339
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• 2017

Here we report the draft genome sequence of the Caballeronia sordidicola strain PAMC 26633, isolated from Psoroma species, a lichen material from Barton Peninsula, King George Island in Antarctica. As we have observed in previous genomic studies in the genus Caballeronia from polar lichen, draft genomic sequences of PAMC 26633 had an assortment of genes of ecological importance and of biotechnical potentials, which include diverse metabolic genes for carbohydrates, amino acids, and genes for nitrogen/sulfur metabolisms, stress responses, membrane transporters, antibiotic resistance, and heavy metal resistance. CRISPR genes and sequences were not found and there were some phage remnants and transposons.

• Korean journal of applied entomology
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• v.14 no.3 s.24
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• pp.111-131
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• 1975

The study has been carried out to investigate the occurrence, damage, characteristics of the pathogen, environmental conditions affecting the disease outbreak, varietal resistance, forecasting, and chemical control of bacterial leaf blight of rice in Korea since 1964. Bacterial leaf blight of rice became a major disease in Korea since 1960. A correlation was found between the annual increase of epidemics and increase of cultivation area of susceptible varieties, Jinheung, Keumnampung etc. Areal damage within the country showed that the more was at southern province, Jeonnam, Gyeongnam and western coast, and at flooded rice paddy. Yield reduction directly related with the amount of infection on upper leaves at heading stage. Fifty per cent of reduction resulted when the lesion area was more than 60 per cent. Less than 20 per cent of lesion area, however, was not affected so much on yield loss One hundred and six isolates collected from all over the country were classified as 8 strains by using 4 different bacteriophages in 1973. It was, however, only two in 1965. There were some specificities on varietal distributions among the strains such as that the Jinheung attacked mainly by strain A, B, C and I, those attack Kimmaze were A, B, H and I. Most strains were found from Tongil except D and E, whereas Akibare was only variety that attacked by strain E. Low temperature, high humidity, heavy rainfall and insutficient daylight favored the disease epidemics. Especially, typhoon and flooding at heading stage were critical factors. The earlier transplanting the more disease was resulted, and more nitrogen fertilizer application accerelated the diseased development in general. The resistance to the disease varied by growing stage of the sane plants. All of recommended varieties in Korea were susceptible to the disease except Norm No. 6 and Sirogane which moderately resistant. The pathogen, Xanthomonas oryzae, was detectable from extract of healthy seedlings that were grown in the field with an heavy infection previous year. The more bacteriophage in irigation water resulted the more disease outbreak, and the existence of more than 50 bacteriophages in 1ml. of irrigation water were necessary to initiate the disease out break. The curves representing occurrence of bacteriophages and disease outbreak were similar with 15 days interval. The survey of bacteriophage occurrence can be utilized in forecasting of the disease two weeks ahead of disease outbreak. Three applications of chemicals, Phenazin and Sangkel, in weekly intervals at the early satage of out-break depressed the symptom development, and increased yield by 20per cent. Proper period for the chemical application was just before the number of bacteriophage reaches 50 in 1ml. of irrigation water.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.322-327
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• 2020

Abortive infection systems (Abi) are phage resistance systems that can be prophage-encoded. Here, two genes encoding an Abi system were identified on a prophage sequence contained by the chromosome of the Levilactobacillus brevis strain UCCLBBS124. This Abi system is similar to the two-component AbiL system encoded by Lactococcus lactis biovar. diacetylactis LD10-1. The UCCLBBS124 prophage-derived Abi system (designated here as AbiL₁₂₄) was shown to exhibit specific activity against phages infecting L. brevis and L. lactis strains. Expression of the AbiL₁₂₄ system was shown to cause reduction in the efficiency of plaquing and cell lysis delay for phages of both species.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.327-331
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• 2000

The application of LFH-PCR(long flanking homology region-PCR) for Bacillus subtilis gene disruption is presented. Without plasmid- or phage-vector construction, only by PCR, based on a DNA sequence retrieved from B. subtilis genome data base, kanamycin resistance gene was inserted into two genes of B. subtilis involved in sporulation, spoIIIE and spoIIIG. The effect of gene disruption on subtilisin expression was examined and the sporulation frequency of two mutants was compared to that of the host strain. For this purpose, only 2 or 3 rounds of PCR were required with 4 primers. We first demonstrated the possibility of LFH-PCR for rapid gene disruption to characterize an unknown functional gene of B. subtilis or other prokaryote in the genomic era.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.317-322
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• 1989

A gene can be selectively overexpressed in E. coli by utilizing the phage T7 RNA polymerase's stringent recognition and active transcription of the T7 promoter. The T7 expression system was constructed such that the T7 RNA polymerase gene is under the control of lacUV5 promoter in one plasmid, and that the target gene, the promoterless chloramphenicol acetyltransferase (CAT) gene with E. coli ribosome binding site is under the control of T7 promoter in the other plasmid. Only the E. coli cells containing both plasmids show high resistance to chloramphenicol. When the copy number of the runaway plasmid containing the polymerase gene was varied by a temperature shift, amounts of the CAT protein synthesized upon induction was correspondingly changed as shown in SDS gel electrophoresis.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.1-11
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• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.134-136
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• 2017

Lactobacillus salivarius KLW001, a species of lactic acid bacteria (LAB), was isolated from a weaning piglet in a swine farm, South Korea, to develop an antimicrobial probiotic strain for piglets. Herein, we report the draft genome sequence of the strain. The genome contains 2,326,706 bp with a G+C content of 33.0% in 166 contigs (${\geq}500bp$). From the genome, we found out 4 genes related to antibiotic resistance, 36 genes for phages, 3 genes for bile hydrolysis, and 27 CRISPR spacers.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.173-180
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• 1988

Chromosomal gene transferable hybrid plasmids, RP4::Mu cts and RP4::mini-Mu, were transferred by conjugation from E. coli to Pseudomonas strains. In order to use for recipient cells of RP4::Mu cts and RP4:: mini-Mu, plasmid-free Pseudomonas strains were characterized for their antobiotic resistance, aromatic hydrocarbon utility and degradation patterns of chlorinated herbicide. Transfer frequencies of RP4::mini-Mu exhibited about $10^{-2}$ to $10^{-4}$, while those of RP4::Mu cts exhibited very low value of $10^{-7}$ in recipients tested except Pseudomonas aeruginosa KU557. Existance of hybrid plasmids in Pseudomonas transconjugants were identified by their antibiotic resistance and agarose gel electrophoresis. In case of RP4::Mu cts transconjugants it was also confirmed by demonstrating that they were capable of releasing phage and forming plaques at $43^{\circ}C$. Plaque forming unit of the transconjugants was about $10^{5}$. It was shown by the stability test that RP4::Mu cts and RP4::mini-Mu in Pseudomonas were relatively stable.

• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.319-324
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• 1986

After intraspecific fusion of Lactobacillus casei protoplasts, the recombinants have been studied for their lactose utilization, protease activity and phage resistance. L. casei C-M phenotypes constituted 46% of the fused cells when tested against phages, and L. casei 3-M phenotypes 42% of the fused cells, and 12% of the recombinants developed the resistance to both parent types of phages. The acid production and proteolytic activity of recombinants evidenced the similar trends. There was no difference in Hind III digests of plasmid DNA between parent cells and recombinants, but the reconlbinant cells were found to possess only one type of plasmid, either of 1. casei C-M or of L. casei 3-M.

• Korean Journal of Microbiology
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• v.54 no.2
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• pp.152-154
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• 2018

Klebsiella pneumoniae is a Gram-negative, rod-shape bacterium causing disease in human and animal lungs. K. pneumoniae has been often found to gain antimicrobial resistance, thus it has been difficult to treat K. pneumoniae infection with antibiotics. For such infection, bacteriophage can provide an alternative approach for pathogenic bacterial infection with antimicrobial resistance, because of its sensitivity and specificity to the host bacteria. Bacteriophage KP1 was isolated in sewage and showed specific infectivity to K. pneumoniae. Here, we report the draft genome sequence of Klebsiella pneumoniae phage KP1. The draft genome of KP1 is 167,989 bp long, and the G + C content is 39.6%. The genome has 295 predicted ORFs and 14 tRNA genes. In addition, it encodes various enzymes which involve in lysis of the host cell such as lysozyme and holin.