• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1529-1535
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• 2013

Tuberculosis is a worldwide epidemic disease caused by Mycobacterium tuberculosis, with an estimated one-third of the human population currently affected. Treatment of this disease with aminoglycoside antibiotics has become less effective owing to antibiotic resistance. Recent determination of the crystal structure of the M. tuberculosis Rv3168 protein suggests a structure similar to that of Enterococcus faecalis APH(3')-IIIa, and that this protein may be an aminoglycoside phosphotransferase. To determine whether Rv3168 confers antibiotic resistance against kanamycin, we performed dose-response antibiotic resistance experiments using kanamycin. Expression of the Rv3168 protein in Escherichia coli conferred antibiotic resistance against $100{\mu}M$ kanamycin, a concentration that effected cell growth arrest in the parental E. coli strain and an E. coli strain expressing the $Rv3168^{D249A}$ mutant, in which the catalytic Asp249 residue was mutated to alanine. Furthermore, we detected phosphotransferase activity of Rv3168 against kanamycin as a substrate. Moreover, docking simulation of kanamycin into the Rv3168 structure suggests that kanamycin fits well into the substrate binding pocket of the protein, and that the phosphorylation-hydroxyl-group of kanamycin was located at a position similar to that in E. faecalis APH(3')-IIIa. On the basis of these results, we suggest that the Rv3168 mediates kanamycin resistance in M. tuberculosis, likely through phosphotransferase targeting of kanamycin.

• Archives of Pharmacal Research
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• 제21권4호
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• pp.470-474
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• 1998

A kanamycin producer, Streptomyces kanamyceticus IFO 13414 is highly resistant to kanamycin. Cloning of the kanamycin resistance genes in S. lividans 1326 with pIJ702 gave several kanamycin resistant transformants. Two transformants, S. lividans SNUS 90041 and S. lividan. SNUS 91051 showed similar resistance patterns to various aminoglycoside antibiotics. Gene mapping experiments revealed that plasmids pSJ5030 and pSJ2131 isolated from the transformants have common resistant gene fragments. Subcloning of pSJ5030 gave a 1.8 Kb gene fragment which showed resistance to kanamycin. Cell free extracts of S. lividans SNUS 90041, S. lividans SNUS 91051 and subclone a S. lividans SNUS 91064 showed kanamycin acetyltransferase activity. The detailed gene map is included.

• Journal of Microbiology and Biotechnology
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• 제6권3호
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• pp.219-220
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• 1996

The pKH2 isolated from the multidrug-resistant Staphylococcus aureus SA2 is a 40.98-kb plasmid and mediates resistance to ampicillin, clindamycin, erythromycin, kanamycin, and streptomycin. The 3.4-kb HindIII fragment conferring kanamycin resistance was cloned from the pKH2 into pBluescriptII $KS^+$ and partial sequence determination of that fragment was carried out. Sequence analysis revealed that the kanamycin resistance gene which encoded aminoglycoside 3'-phosphotransferase was linked to the streptothricin resistance gene. But a nonsense mutation was found in the streptothricin resistance gene and this mutation resulted in a truncated protein of streptothricin acetyltransferase. Homology comparison with nucleotide sequence databases revealed that the 3.4-kb HindIII fragment of pKH2 had been derived not from S. aureus but from Gram-negative Campylobacter coli.

• 한국가금학회지
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• 제7권1호
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• pp.53-64
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• 1980

A total of 1503 specimens were submitted to the Poultry Disease Diagnostic Service Laboratory during the year 1966 and 1978. The most frequently diagnosed diseases in order of prevalence were avian mycoplasmosis, staphylococcosis, colibacillosis, salmonellosis and pullorum disease, the percentages of the conditions being 24.6%, 20.0%, 18.0%, 12.6% and 6.4%, respectively, The drug resistance of pathogenic mirnoorganisms isolated during the year 1978 from chicken with colicabacillosis, staphylococcosis or salmonellosis were investigated by the use of disc diffusion technique, the results being as follow. 1) Drug resistance of 63 strains of Escherichia coli More than 95% of the strains tested were sensitive to colistin and gentamicin. The percentages of strains sensitive to kanamycin, chloramphenicol, ampicillin and nitrofurantoin were 66.7%, 60.3%, 60.3% and 47.6%, respectively. Majority of the strains were highly resistant to streptomycin and tetracyline. All the strains were resisistant to bacitracin lincomycin, oleandomycin, penicillin and erythromycin. All the strains tested were resistant to more than two among 10 drugs in common use such as penicillin, erythromycin, streptomycin, tetracycline, neomycin, chloramphenicol, kanamycin, ampicillin and gentamicin, and 27 different resistance patterns were noted. The most frequent multiple resistance pattern was PC, EM, SM and TC (11.1%). 2) Drug resistance of 48 strains of Salmonella More than 95% of the strains tested were sensitive to colistin, gentamicin ana ampicillin. The percentages of st rains sensitive to kanamycin, tetracycline, neomycin and nitrofurantoin were 81,3%, 79%, 72.9%, and 68.0% respectively. None of them was sensitive to streptomycin, oleandomycin, erythromycin, lincomycin and bacitracin. All the strains were resistant to more than one among 7 drugs in common use such as streptomycin, erythromycin, neomycin, tetracycline, kanamycin, ampicillin and gentamicin. The most frequent resistance pattern was SM and EM(66.7%). 3) Drug resistance of 54 strains of Staphylococci All the strains tested were sensitive to gentmaicin, kanamycin and cephalothin. Majority of them were highly sensitive to bacitracin, methicillin, nitrofurantoin and chloramphenicol. The Percentages of strains sensitive to streptomycin, ampicillin, lincomycin and tetracycline were 66.7%, 55.6%, 44.4% and 27.8%, respectively. Among them, 51 strains were resistant to more than one among 11 drugs in common use such as tetracycline, lincomycin, ampicillin, penicillin, streptomycin, erythromycin, neomycin, oleandomycin, chloramphenicol, methicillin and bacitracin, and thirty one different resistance patterns were noted.

• Bulletin of the Korean Chemical Society
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• 제15권7호
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• pp.568-571
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• 1994

Streptmyces fradiae NRRL B1195 and Streptomyces kanamyceticus IFO 13414 are highly resistant to the antibiotics they produce. The ribosomes of these organisms are found to be susceptible to the antibiotics, but the cell free extract of S fradiae is found to contain a phosphotransferase and an acetyltransferase which inactivate kanamycin and neomycin, and that of S. kanamyceticus an acetyltransferse which inactivates kanamycin and neomycin. The resistance of these organisms against streptomycin is found to be due to the resistant ribosomes; actually streptomycin activates their ribosomal systems for the synthesis of polyphenylalanine.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.346-353
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• 2005

A 50-kb chromosome DNA region was isolated from Streptomyces kanamyceticus by screening the fosmid genomic library, using the 16S rRNA methylase gene (kmr) as a probe. Sequence analysis of this region revealed 42 putative open reading frames (ORFs), which included biosynthetic genes such as genes responsible for 2-deoxystreptamine (2­DOS) biosynthesis as well as genes for resistance and regulatory function. Also, the kanamycin acetyltransferase gene (kac) was characterized by in vitro enzyme assay, which conferred E. coli BL21 (DE3) with 10, 50, and 80-times higher resistance to kanamycin A, tobramycin, and amikacin, respectively, than the control strain had, thus strongly indicating that the isolated gene cluster is very likely involved in kanamycin biosynthesis. This work provides a solid basis for further elucidation of the kanamycin biosynthesis pathway as well as the productivity improvement and construction of new hybrid antibiotics.

• 생명과학회지
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• 제8권5호
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• pp.537-549
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• 1998

실험대상 병원내 27개소의 공기중에서 30분 동안 낙하균을 여름과 겨울에 채취하여, 총 세균 수와 포도상 구균속 및 진균의 수를 비교하고, 각각의 균을 동정하고, 분리된 주요 세균에 대한 항생물질 감수성 검사를 실시하였다. 분리된 총 세균 수, 포도구균속의 수, 진균의 수는 여름에 각각 26개, 17개, 2개였으며, 겨울에는 각각 19개, 8개, 2개로 여름이 더 많았다. 분리 동정된 세균 종은 Staphylococcus dpidermidis가 가장 많았으며, 그 다음이 Staphylococcus aureus, Aerococcus spp., Staphylococcus saprophyticus, Micrococcus spp., Bacilluc spp. 등의 순이 었다. 병원내 공기중에서 분리된 진균은 Aspergillus spp., Cephalosporium spp., Curvularia spp., Penicillium spp., Phialophora spp. 등의 순으로 많이 분리되었다. 분리된 109주의 Staphylococcus epidermidis는 tetracycline에 45.0%, methicillin에 40.4%, erythromycin에 31.2%, kanamycin에 24.8%, gentamy-cin에 16.5%가 저항성 균주이었다. 분리된 76주의 Staph-ylococcus aureus는 erythromycin에 71.1%, methicillin에 63.2%, kanamycin에 44.7%, tetracycline에 39.5%, ampicillin에 32.9%가 저항성 균주이었다. 분리된 67주의 Aerococcus spp.는 erythromycin에 26.9%, methicillin에 25.4%, tetracycline에 22.4%, kanamycin에 20.9%가 저항성 균주이었으나, vancomycin에는 저항성 균이 없었다. 분리된 48주의micrococcus spp.는 tetracycline에 27.0%, erythomycin과 methicillin에 각각 22.9%, kanamycin에 20.8%가 저항성 균주이었다. 분리된 37주의 Staphylococcus saprophyticus는 cephalothin에 35.4%, methicillin과 ampicillin에 32.4%, erythromycin과 kanamycin에 각각 27.0%, tetracycline에 21.6%가 저항성 균주이었다.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1471-1478
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• 2022

2'-Fucosyllactose (2'-FL), the most abundant fucosylated oligosaccharide in human milk, has multiple beneficial effects on human health. However, its biosynthesis by metabolically engineered Escherichia coli is often hampered owing to the insolubility and instability of α-1,2-fucosyltransferase (the rate-limiting enzyme). In this study, we aimed to enhance 2'-FL production by increasing the expression of soluble α-1,2-fucosyltransferase from Helicobacter pylori (FucT2). Because structural information regarding FucT2 has not been unveiled, we decided to improve the expression of soluble FucT2 in E. coli via directed evolution using a protein solubility biosensor that links protein solubility to antimicrobial resistance. For such a system to be viable, the activity of kanamycin resistance protein (Kan^R) should be dependent on FucT2 solubility. Kan^R was fused to the C-terminus of mutant libraries of FucT2, which were generated using a combination of error-prone PCR and DNA shuffling. Notably, one round of the directed evolution process, which consisted of mutant library generation and selection based on kanamycin resistance, resulted in a significant increase in the expression level of soluble FucT2. As a result, a batch fermentation with the ΔL M15 pBCGW strain, expressing the FucT2 mutant (F#1-5) isolated from the first round of the directed evolution process, resulted in the production of 0.31 g/l 2'-FL with a yield of 0.22 g 2'-FL/g lactose, showing 1.72- and 1.51-fold increase in the titer and yield, respectively, compared to those of the control strain. The simple and powerful method developed in this study could be applied to enhance the solubility of other unstable enzymes.

• 식물조직배양학회지
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• 제28권5호
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• pp.243-248
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• 2001

본 실험은 nptII 및 hpt 유전자가 삽입된 현사시나무를 이용하여 각 항생제 저항성 유전자로 형질전환된 세포의 효율적인 선발 조건을 규명하기 위하여 수행되었다. 액아가 포함된 줄기절편과 잎절편 조직의 생장, 발근 유도, 캘러스 유도로 항생제에 대한 감수성에 대한 효과를 검정하였다. 형질전환되지 않은 대조식물체의 잎절편을 이용한 경우 50 mg/L의 kanamycin이나 2 mg/L hygromycin으로 캘러스 유도 및 생장을 억제할 수 있었으나 형질전환된 식물은 100 mg/L kanamycin, 50 mg/L hygromycin에서도 왕성한 생장을 나타냈다. 절간조직의 개아의 경우 100 mg/L kanamycin, 5 mg/L hygromycin으로 줄기신장을 완전히 억제 가능하였으며, 뿌리유도는 50 mg/L kanamycin, 5 mg/L hygromycin에서 선발이 가능하였다. 형질전환체는 모두 이보다 높은 농도에서 왕성한 생장을 보였다. 형질전환이 되지 않은 세포의 생장을 억제하는 데는 hygromycin이 kanamycin보다 더 효율이 좋은 것으로 나타났다. 따라서 hpt유전자가 npt II 유전자보다 훨씬 강력한 선발표지임이 확인되었으며 엽절편의 캘러스 유도와 생장과 절간조직의 발근유도 모두 항생제에 예민하게 작용하여 형질전환체의 식별에 효과적으로 사용할 수 있음을 알 수 있었다.