• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1040-1043
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• 2008

Klebsiella oxytoca CCUG 15788 is resistant to $Ni^{2+}$ at a concentration of 10 mM and grows in an inducible manner when exposed to lower concentrations of $Ni^{2+}$. The complete genomic sequence of a 4.2-kb HindIII-digested fragment of this strain was determined from genomic DNA. It was shown to contain four nickel resistance genes (nirA, nirB, nirC, and nirD) encoding transporter and transmembrane proteins for nickel resistance. When the plasmid pKOHI4, encoding nirABCD, was transformed into Escherichia coli JM109, the cells were able to grow in Tris-buffered mineral medium containing 3 mM nickel. TnphoA'-1 insertion mutants in the four nickel genes nirA, nirB, nirC, and nirD showed nickel sensitivity. The nir genes were heterogeneously expressed in E. coli, suggesting functional roles of these genes in nickel resistance.

• Parasites, Hosts and Diseases
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• 제60권2호
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• pp.109-116
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• 2022

Drug resistance is an important problem hindering malaria elimination in tropical areas. Point mutations in Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes confer resistance to antifolate drug, sulfadoxine-pyrimethamine (SP) while P. falciparum chloroquine-resistant transporter (Pfcrt) genes caused resistance to chloroquine (CQ). Decline in Pfdhfr/Pfdhps and Pfcrt mutations after withdrawal of SP and CQ has been reported. The aim of present study was to investigate the prevalence of Pfdhfr, Pfdhps, and Pfcrt mutation from 2 endemic areas of Thailand. All of 200 blood samples collected from western area (Thai-Myanmar) and southern area (Thai-Malaysian) contained multiple mutations in Pfdhfr and Pfdhps genes. The most prevalent haplotypes for Pfdhfr and Pfdhps were quadruple and double mutations, respectively. The quadruple and triple mutations of Pfdhfr and Pfdhps were common in western samples, whereas low frequency of triple and double mutations was found in southern samples, respectively. The Pfcrt 76T mutation was present in all samples examined. Malaria isolated from 2 different endemic regions of Thailand had high mutation rates in the Pfdhfr, Pfdhps, and Pfcrt genes. These findings highlighted the fixation of mutant alleles causing resistance of SP and CQ in this area. It is necessary to monitor the re-emergence of SP and CQ sensitive parasites in this area.

• 식물병연구
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• 제25권2호
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• pp.49-61
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• 2019

식물 바이러스는 작물 생산량 손실을 일으키는 주요 병원체 중 하나로, 돌연변이 발생이 빈번하고 치료 약제가 개발되어 있지 않아 방제가 매우 어렵다. 이러한 바이러스병을 방제하기 위한 가장 효과적인 방법은 저항성 품종을 재배하는 것이며, 바이러스 저항성 품종을 개발하기 위해서는 바이러스와 기주 식물 간의 다양한 유전자적 상호작용에 대한 정확한 이해가 필요하다. 열성 저항성은 병원체가 살아가는데 필요한 식물 유전자가 결핍되었을 때 획득되는데, 저항성 유전자(R gene)에 의해 유도되는 우성 저항성에 비해 넓은 범위의 저항성을 발현하고 돌연변이 출현에 쉽게 저항성이 깨지지 않는 특성을 보인다. 현재까지 알려진 바이러스병에 대한 열성 저항성 유전자는 대부분 순행유전학(forward genetics)를 통해 밝혀졌으나, 최근 CRISPR/Cas9 등을 이용한 유전자 교정 기술의 급속한 발전에 힘입어 역유전학(reverse genetics)을 통한 열성 저항성 작물개발의 가능성이 열리고 있다. 이러한 역유전학적 접근을 통한 열성 저항성 작물 개발은 먼저 바이러스 단백질과 상호작용하는 기주 인자를 밝히고 이들간의 상호작용을 억제하도록 하는 기주 인자에 대한 유전자 교정을 통해 이루어 질 수 있다. 본 논문에서는 열성 저항성에 대한 소개와 새로운 열성 저항성 후보 유전 소재 발굴을 위한 기주 인자 연구의 중요성 및 방법을 소개하고, 열성 저항성 작물 개발에 적용할 수 있는 유전자 교정기술의 최신 동향에 관해 정리하였다.

• Molecules and Cells
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• 제24권3호
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• pp.394-408
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• 2007

Several genes/QTLs governing resistance/tolerance to abiotic and biotic stresses have been reported and mapped in rice. A QTL for submergence tolerance was found to be co-located with a major QTL for broad-spectrum bacterial leaf blight (bs-blb) resistance on the long arm of chromosome 5 in indica cultivars FR13A and IET8585. Using the Nipponbare (japonica) and 93-11 (indica) genome sequences, we identified, in silico, candidate genes in the chromosomal region [Kottapalli et al. (2006)]. Transcriptional profiling of FR13A and IET8585 using a rice 22K oligo array validated the above findings. Based on in silico analysis and arraying we observed that both cultivars respond to the above stresses through a common signaling system involving protein kinases, adenosine mono phosphate kinase, leucine rich repeat, PDZ/DHR/GLGF, and response regulator receiver protein. The combined approaches suggest that transcription factor EREBP on long arm of chromosome 5 regulates both submergence tolerance and blb resistance. Pyruvate decarboxylase and alcohol dehydrogenase, co-located in the same region, are candidate downstream genes for submergence tolerance at the seedling stage, and t-snare for bs-blb resistance. We also detected up-regulation of novel defense/stress-related genes including those encoding fumaryl aceto acetate (FAA) hydrolase, scramblase, and galactose oxidase, in response to the imposed stresses.

• BMB Reports
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• 제38권4호
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• pp.420-431
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• 2005

The differentially virulent race T1 of common bunt (Tilletia tritici) was used to inoculate the wheat lines Neepawa (compatible) and its sib BW553 (incompatible) that are nearly isogenic for the Bt-10 resistance gene. Inoculated crown tissues were used to construct a suppression subtractive hybridization (SSH) cDNA library. Of the 1920 clones arrayed from the SSH cDNA library, approximately 10% were differentially regulated. A total of 168 differentially up-regulated and 25 down-regulated genes were identified and sequenced; 71% sequences had significant homology to genes of known function, of which 59% appeared to have roles in cellular metabolism and development, 24% in abiotic/biotic stress responses, 3% involved in transcription and signal transduction responses. Two putative resistance genes and a transcription factor were identified among the up regulated sequences. The expression of several candidate genes including a lipase, two non-specific lipid transfer proteins (ns-LTPs), and several wheat pathogenesis-related (PR)-proteins, was evaluated following 4 to 32 days post-inoculation in compatible and incompatible interactions. Results confirmed the higher overall expression of these genes in resistant BW553 compared to susceptible Neepawa, and the differential up-regulation of wheat lipase, chitinase and PR-1 proteins in the expression of the incompatible interaction.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.101.1-101
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• 2003

Lipopolysaccharide, siderophore, and cyclic dipeptide have been shown to be necessary for ISR induction by pseudomnads. However, there is no report on cloning of genes or generating specific mutants involving in ISR activity. A biological control bacteium P. chlororaphis O6 induces resistance to Erwinia carotovora subsp. carotovara SCCI in tobacco and induces drought resistance in Arabidopsis. To isolate genes involved in ISR activity and induction of drough resistance of O6, we constructed Tn5 mutants and were used to screen for ISR activity and drought resistance activity using microtiter assay with tobacco and Arabidopsis. Thirty-three ISR-deficient mutants were selected, and the nine ISR-deficient mutants were also lost activity of drought resistance. The flanking sequence analysis of the ISR and drought resistance-deficient mutants showed that a gacS gene encoding a two-component sensor kinase, and a mce gene encoding a protein involved in mycobacterial cell entry were mutated. The flanking sequence of each Tn5 mutant altered ISR activity is currently under investigation. These results indicate that gacS and mce are important genes in induction of ISR activity and drought resistance of P. chlororaphis O6. Our works will open opportunities for identification of bacterial genes or traits that are involved in ISR activity and induced drought resistance of P. chlororaphis O6.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 추계국제학술대회
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• pp.65-65
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• 2020

Bakanae disease, caused by Gibberella fujikuroi, is one of the most devastating diseases threatening rice production in Korea. In recent years, the incidence of bakanae disease became alarming due to the mechanical transplanting practice where the spread of bakanae can be amplified during accelerating seeds growth, due to the use of seeding boxes. The development of resistant rice cultivars could be the primary and effective method for controlling bakanae disease. However, the effects of individual resistance genes are relatively small. Therefore, pyramiding of bakane R genes in rice breeding is a promising strategy having a high potential to mitigate the advert effects of bakanae disease. This study employed a gene pyramiding approach to develop bakanae disease resistant rice lines carrying qBK1, qFfR1 introduced from rice line MY299BK and cv. Nampyeong, respectively. The MY299BK carries qBK1 introduced from cv. Shingwang, which was found to have a high resistance compare to Nampyeong. In addition, the pyramiding effect of the qBK1 and qFfR1 resistance genes were investigated, and the presence or absence of these genes helped us investigate their interaction through bioassay method and MAS. Furthermore, the distribution of resistance in the population showed a biased distribution toward resistance in the F6:7 populutions. However, we could not confirm the accumulation effect of the resistance gene, but the difference between the two genes by the SN2 marker was confirmed. Therefore, the qBK1 gene harbored by MY299BK appears to be different from the qFfR1 carried by Nampyeong, suspected to possess a different bakanae disease resistant gene different from those found in MY299BK and Nampyeong.

• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.137-142
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• 2015

Trimethoprim-sulfamethoxazole (TMP-SMX) has been used for the treatment of urinary tract infections, but increasing resistance to TMP-SMX has been reported. In this study, we analyzed TMP-SMX resistance genes and their relatedness with integrons and insertion sequence common regions (ISCRs) in uropathogenic gram-negative bacilli. Consecutive nonduplicate TMP-SMX nonsusceptible clinical isolates of E. coli, K. pneumoniae, Acinetobacter spp., and P. aeruginosa were collected from urine. The minimal inhibitory concentration was determined by Etest. TMP-SMX resistance genes (sul and dfr), integrons, and ISCRs were analyzed by PCR and sequencing. A total of 45 E. coli (37.8%), 15 K. pneumoniae (18.5%), 12 Acinetobacter spp. (70.6%), and 9 Pseudomonas aeruginosa (30.0%) isolates were found to be resistant to TMP-SMX. Their MICs were all over 640. In E. coli and K. pneumoniae, sul1 and dfr genes were highly prevalent in relation with integron1. The sul3 gene was detected in E. coli. However, in P. aeruginosa and Acinetobacter spp., only sul1 was prevalent in relation with class 1 integron; however, dfr was not detected and sul2 was less prevalent than in Enterobacteriaceae. ISCR1 and/or ISCR2 were detected in E. coli, K. pneumoniae, and Acinetobacter spp. but the relatedness with TMP-SMX resistance genes was not prominent. ISCR14 was detected in six isolates of E. coli. In conclusion, resistance mechanisms for TMP-SMX were different between Enterobacteriaceae and glucose non-fermenting gram-negative bacilli. Class 1 integron was widely disseminated in uropathogenic gram-negative baciili, so the adoption of prudent use of antimicrobial agents and the establishment of a surveillance system are needed.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2000년도 International Symposium on Bioinformatics
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• pp.74-82
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• 2000

Prostate cancer initially responds and regresses in response to androgen depletion therapy, but most human prostate cancers will eventually recur, and re-grow as an androgen independent tumor. Once these tumors become hormone refractory, they usually are incurable leading to death for the patient. Little is known about the molecular details of how prostate cancer cells regress following androgen ablation and which genes are involved in the androgen independent growth following the development of resistance to therapy. Such knowledge would reveal putative drug targets useful in the rational therapeutic design to prevent therapy resistance and control androgen independent growth. The application of genome scale technologies have permitted new insights into the molecular mechanisms associated with these processes. Specifically, we have applied functional genomics using high density cDNA microarray analysis for parallel gene expression analysis of prostate cancer in an experimental xenograft system during androgen withdrawal therapy, and following therapy resistance, The large amount of expression data generated posed a formidable bioinformatics challenge. A novel template based gene clustering algorithm was developed and applied to the data to discover the genes that respond to androgen ablation. The data show restoration of expression of androgen dependent genes in the recurrent tumors and other signaling genes. Together, the discovered genes appear to be involved in prostate cancer cell growth and therapy resistance in this system. We have also developed and applied tissue microarray (TMA) technology for high throughput molecular analysis of hundreds to thousands of clinical specimens simultaneously. TMA analysis was used for rapid clinical translation of candidate genes discovered by cDNA microarray analysis to determine their clinical utility as diagnostic, prognostic, and therapeutic targets. Finally, we have developed a bioinformatic approach to combine pharmacogenomic data on the efficacy and specificity of various drugs to target the discovered prostate cancer growth associated candidate genes in an attempt to improve current therapeutics.

• 대한임상검사과학회지
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• 제39권3호
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• pp.161-166
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• 2007

To develop a rapid and reliable single-tube-based PCR technique for detection simultaneously the quinolone resistance qnrA, qnrB and qnrS genes. After multiple alignment, primers were designed to detect known qnr variants. I was used for A total of 43 extented-spectrum ${\beta}$-lactamases (ESBLs) producing Escherichia coli and Klebsiella pneumoniae isolated from university hospital were tested for screening, as with qnr genes. In optimized conditions, all positive controls confirmed the specificity of the PCR primers. Out of 43 isolates, qnrA genes were detected 19 (44.2%), qnrB genes 5 (11.7%), qnrS genes 15 (34.9%) and 8 (18.6%) isolates were not detected. I report here a fast and reliable technique for rapid screening of qnr positive strains to be used for epidemiological surveys.