• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.146-152
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• 2010

Streptomyces clavuligerus NRRL3585 produces a clinically important $\beta$-lactamase inhibitor, clavulanic acid (CA). In order to increase the production of CA, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene (gap) was deleted in S. clavuligerus NRRL3585 to overcome the limited glyceraldehyde-3-phosphate pool; the replicative and integrative expressions of ccaR (specific regulator of the CA biosynthetic operon) and claR (Lys-type transcriptional activator) genes were transformed together into a deletion mutant to improve clavulanic acid production. We constructed two recombinant plasmids to enhance the production of CA in the gap1 deletion mutant of S. clavuligerus NRRL3585: pHN11 was constructed for overexpression of ccaR-claR, whereas pHN12 was constructed for their chromosomal integration. Both pHN11 and pHN12 transformants enhanced the production of CA by 2.59-fold and 5.85-fold, respectively, compared with the gap1 deletion mutant. For further enhancement of CA, we fed the pHN11 and pHN12 transformants ornithine and glycerol. Compared with the gap1 deletion mutant, ornithine increased CA production by 3.24- and 6.51-fold in the pHN11 and pHN12 transformants, respectively, glycerol increased CA by 2.96- and 6.21-fold, respectively, and ornithine and glycerol together increased CA by 3.72- and 7.02-fold, respectively.

• 한국균학회지
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• 제20권3호
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• pp.222-228
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• 1992

사철 느타리버섯 영양요구성(營養要求性) 균주(菌株)를 팽이버섯 leu 2 유전자를 지닌 pM 301 백터를 이용(利用)하여 영양요구성(營養要求性)을 보완(補完) 시킴으로써 형질전환(形質轉換) 하였다. 형질전환균주(形質轉換菌株)의 균사생장(菌絲生長)을 버섯 완전배지(完全培地)나 버섯 최소(最小) 배지(培地)에서 비교(比較)하였다. 형질전환주(形質轉換株)는 1 핵(核) 균사(菌絲)와 교배(交配)후 자실체(子實體) 형태(形態)를 비교(比較)하고 포자 분석(分析)에 의하여 유전분석(分析)을 하였다. 자실체(子實體) 발생(發生)과 자실체(子實體) 모양이 형질전환주(形質轉換株)는 모균주와 다른 특성(特性)이 나타났다. 모균주(母菌株)는 교배형(交配型)이 $A_1B_1$으로 $A_2B_1$ 교배형(交配型)인 1핵(核) 균주(菌株)와 교배(交配)에 의하여 자실체(子實體)를 형성(形成)하지 못하나 형질전환주(形質轉換株)는 교배형(交配型)이 $A_1B_1$이고 $A_2B_1$ 1핵(核) 균주(菌株)와 교배(交配) 하였을때 자실체(子實體)를 형성(形成)하였다.

• 한국버섯학회지
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• 제9권1호
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• pp.3-16
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• 2011

In the bipolar basidiomycete Pholiota nameko, a pair of homeodomain protein genes located at the A mating-type locus regulates mating compatibility. In the present study, we used a DNA-mediated transformation system in P. nameko to investigate the homeodomain proteins that control the clamp formation. When a single homeodomain protein gene (A3-hox1 or A3-hox2) from the A3 monokaryon strain was introduced into the A4 monokaryon strain, the transformants produced many pseudo-clamps but very few clamps. When two homeodomain protein genes (A3-hox1 and A3-hox2) were transformed either separately or together into the A4 monokaryon, the ratio of clamps to the clamp-like cells in the transformants was significantly increased to approximately 50%. We, therefore, concluded that the gene dosage of homeodomain protein genes is important for clamp formation. When the sip promoter was connected to the coding region of A3-hox1 and A3-hox2 and the fused fragments were introduced into NGW19-6 (A4), the transformants achieved more than 85% clamp formation and exhibited two nuclei per cell, similar to the dikaryon (NGW12-163 ${\times}$ NGW19-6). The results of real-time RT-PCR confirmed that sip promoter activity is greater than that of the native promoter of homeodomain protein genes in P. nameko. So, we concluded that nearly 100% clamp formation requires high expression levels of homeodomain protein genes and that altered expression of the A mating-type genes alone is sufficient to drive true clamp formation.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.489-493
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• 1988

Starch로부터 ethanol을 직접적으로 발효 생산할 수 있는 새로운 효모 균주를 개발하고자 glucoamylase 생성균으로 알려진 Saceharomyces diastaticus의 glucoamylase gene을 cloning vector를 사용하지 않고 S, cerevisiae에 transformation시켰다. Li$_2$SO$_4$, 처리로써 competent화 한 S, cerevisiae의 Intact cells을 recipient로 하여 BamHI으로 partial digestion한 S, diastaticus의 chromosomal DNA를 transformation시키고 starch를 유일한 탄소원으로 함유한 최소 배지상에서 starch 자화능을 marker로 하여 transformant를 선별한 결과, 8.5$\times$$10^{-7}$ 빈도로 transformant를 얻었다. Transformant의 특성을 recipient 및 donor와 비교하기 위해 copper resistance와 당 발효능을 조사한 결과, donor인 S, diastaticus와 동일한 성질로서 표현된 maltose와 starch 발효능을 제외하고는 800ppm 농도까지 생육 가능한 copper resistance와 galactose 발효능 등에 있어서는 recipent와 동일하게 나타났다. 또한 transformant가 생성하는 glucoamylase의 그 작용에 있어서의 최적온도와 최적pH를 조사하여 본 바 각각 pH5.0, 50C로서 donor의 glucoamylase와 동일함을 알 수 있었다.

• 미생물학회지
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• 제45권1호
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• pp.82-85
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• 2009

내분비장애물질은 분해가 매우 어려워 자연계에서 먹이그물을 통하여 사람에게 농축 전달된다. 이들은 정상적인 내분비계에 혼란을 일으키며, 특히 성호르몬의 작용에 많은 피해를 준다. 이를 효율적으로 분해하고 이들의 에스트로겐 활성을 제거하고자 백색부후균의 하나인 아교버섯(Phlebia tremellosa)을 활용하여 4가지 내분비계 장애물질의 분해에 대한 실험을 수행하였다. 아교버섯의 manganese peroxidase (MnP) 활성을 높이기 위하여 구름버섯의 MnP 유전자를 아교버섯에 도입하여 형질전환체를 확보하였으며 이들은 유전적으로 MnP 활성을 안정되게 나타냈다. 내분비 장애물질을 분해하는 조건에서 내분비장애 물질에 따라 30${\sim}$45%의 분해율을 보인 야생형에 비하여 이 형질전환체들 중 T5는 70${\sim}$88%의 분해율을 보였으며 에스트로겐 활성의 제거에도 약 2배 향상된 능력을 보였다.

• 한국미생물·생명공학회지
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• 제14권3호
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• pp.213-218
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• 1986

B. amyloliquefaciens의 $\alpha$-amylase 유전자가 S. cerevisiae 내에서 형질발현하는 가를 조사하기 위하여 본, 연구에서 YRp7 plasmid에 B. amyloliquefaciens amylase유전자를 cloning하여 만든 pEA24를 형질전환시켰다. 먼저 YRp7 plasmid를 이용하여 형질전환 최적 조건을 검토하여 본 바, PH 7과 8사이, 반응온도 3$0^{\circ}C$에서 40%의 polyethylene glycol(MW 4,000)을 처리한 후 2 %의 agar를 함유한 재생배지에 중층도말 하였을 때 형질전환율이 가장 높았다. 형질전환주로부터 생성된 amylase의 활성을 측정한 결과, S. cerevisiae에서 약간의 amylase활성을 나타내어 최고 B. amyloliquefaciens의 2% 정도였고, 세포외효소는 검출되지 않았다. 이들 형질전환 주가 가지고 있는 pEA24 plasmid의 안정성을 조사한 결과 YRp7보다 불안정하였으며, 추출한 DNA를 전기영동하여 그 band를 확인하였다.

• Journal of Microbiology
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• 제44권4호
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• pp.383-395
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• 2006

Four different Trichoderma strains, T. harzianum CECT 2413, T. asperellum T53, T. atroviride T11 and T. longibrachiatum T52, which represent three of the four sections contained in this genus, were transformed by two different techniques: a protocol based on the isolation of protoplasts and a protocol based on Agrobacterium-mediated transformation. Both methods were set up using hygromycin B or phleomycin resistance as the selection markers. Using these techniques, we obtained phenotypically stable transformants of these four different strains. The highest transformation efficiencies were obtained with the T. longibrachiatum T52 strain: 65-70 $transformants/{\mu}g$ DNA when transformed with the plasmid pAN7-1 (hygromycin B resistance) and 280 $transformants/l0^7$ spores when the Agrobacterium-mediated transformation was performed with the plasmid pUR5750 (hygromycin B resistance). Overall, the genetic analysis of the transform ants showed that some of the strains integrated and maintained the transforming DNA in their genome throughout the entire transformation and selection process. In other cases, the integrated DNA was lost.

• 한국균학회지
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• 제25권3호통권82호
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• pp.233-237
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• 1997

여름느타리버섯의 단포자에 UV를 처리하여 pab 요구성 영양요구주를 작성하였으며 이 균의 균사에서 원형질체를 분리한 후 Coprinus pab 1유전자를 함유하는 plasmid를 이용하여 prototrophy로 형질전환 하였다. 형질전환율은 ${\mu}g$의 DNA 당 5개의 형질전환주를 얻을 수 있었다. 형질전환주는 Southern 분석결과 염색체 DNA 속으로 integration된 것으로 확인되었으며 영양생장과 생식 생장시 모두 안정하게 유지되었다. 형질전환주와 화합성인 다른 영양요구주와 교배후 자실체의 포자를 분리하여 유전분석 결과 pab 생합성 유전자 보다는 그 유전자 주위에 integration이 일어난 것으로 추정되었다.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.330-336
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• 2005

Lactococcus lactis A164 is a nisin Z-producing strain isolated from kimchi. Its antimicrobial spectrum has been found to be active against most Gram-positive bacteria tested, yet inactive against Gram-negative bacteria [3]. Accordingly, to overcome this drawback, the current study attempted to express human $\beta$-defensin-l (hBD-l), which kills both Gram-positive and Gram-negative bacteria in L. lactis AI64. When the hBD-l cDNA was introduced using a nisin Z-controlled expression cassette, the L. lactis A164 transformants grew very poorly, due to the bactericidal effect of the expressed hBD-l against the transformants. Therefore, a gene fusion system was designed to reduce the toxicity of the expressed heterologous protein against the host cells. As such, the hBD-l gene was fused to the DsbC- Tag of pET -40b(+), then introduced to L. lactis A 164. The transformants expressed an intracellular 35.6-kDa DsbC-hBD-l fusion protein that exhibited slight activity against the host cells, yet not enough to strongly inhibit the cell growth. To obtain the recombinant hBD-l, the DsbC-hBD-l fusion protein was purified by nickel-affinity column chromatography, and the DsbC-Tag removed by cleaving with enterokinase. The cleaved mature hBD-l exhibited strong bactericidal activity against E. coli JM109, indicating that the recombinant L. lactis A 164 produced a biologically active hBD-I. In addition, the recombinant L. lactis A 164 was also found to produce the same level of nisin Z as the wild-type.

• Journal of Microbiology and Biotechnology
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• 제27권2호
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• pp.306-315
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• 2017

Metabolic engineering with a high-yielding mutant, A. terreus AN37, was performed to enhance the production of itaconic acid (IA). Reportedly, the gene cluster for IA biosynthesis is composed of four genes: reg (regulator), mtt (mitochondrial transporter), cad (cis-aconitate decarboxylase), and mfs (membrane transporter). By overexpressing each gene of the IA gene cluster in A. terreus AN37 transformed by the restriction enzyme-mediated integration method, several transformants showing high productivity of IA were successfully obtained. One of the AN37/cad transformants could produce a very high amount of IA (75 g/l) in shake-flask cultivations, showing an average of 5% higher IA titer compared with the high-yielding control strain. Notably, in the case of the mfs transformants, a maximal increase of 18.3% in IA production was observed relative to the control strain under the identical fermentation conditions. Meanwhile, the overexpression of reg and mtt genes showed no significant improvements in IA production. In summary, the overexpressed cis-aconitate decarboxylase (CAD) and putative membrane transporter (MFS) appeared to have positive influences on the enhanced IA productivity of the respective transformant. The maximal increases of 13.6~18.3% in IA productivity of the transformed strains should be noted, since the parallel mother strain used in this study is indeed a very high-performance mutant that has been obtained through intensive rational screening programs in our laboratory.