• Journal of Microbiology
• /
• 제41권1호
• /
• pp.41-45
• /
• 2003

N crassa mutant strain nap showed reduced growth rate, decreased electric membrane potential, and elevated intracellular ATP content in comparison to the wild type. Blue light induced a hyperpolarization of the membrane potential in both strains. The analysis of oxidative and phosphorylation activities of mitochondria isolated from the two strains has revealed that nap utilized more efficient oxidative pathways. The higher intracellular ATP content in the nap was presumably due to impaired transport systems of the plasma membrane, and to a lesser extent to the functioning of the fully competent respiratory chain. The excess ATP possibly accounts for carotenoid accumulation in the mutant.

• 농업생명과학연구
• /
• 제43권6호
• /
• pp.77-84
• /
• 2009

Using recombinant DNA technology, the vector system containing minimal fragment of a bacterial hemoglobin gene (vgb) was constructed. When this vector was inserted into Escherichia coli, the growth of the host was significantly improved in both viable cell counts and absorbance measurement, compared to that of the wild type strain. In addition, by minimizing the size of bacterial hemoglobin in the vector, the ability of vgb in growth improvement was augmented, due to the reduction of metabolic burden from the maintenance and replication of the plasmid. By using this system, it is expected that the growth of microorganisms can be improved even in the hypoxic condition.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2005년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.231-232
• /
• 2005

Bacteria of Shigella spp. are responsible for shigellosis in humans, a disease characterized by destruction of the colonic epithelium that is induced by the inflammatory response elicited by invasive bacteria. They use a type III secretion system injecting effector proteins into host cells to induce their entry into epithelial cells and triggers apoptosis in macrophages. We present evidence that the effector OspG is a protein kinase that binds various ubiquitinylated ubiquitin-conjugating enzymes (E2s) and blocks degradation of phospho-$I{\kappa}B{\alpha}$ induced upon entry of bacteria into epithelial cells. Transfection experiments confirmed that OspG interferes with the $NF-{\kappa}B$ activation patway by preventing phospho-$I{\kappa}B{\alpha}$ degradation, suggesting that OspG inactivates a component of the $SCF^{{\beta}-TrCP}$ ubiquitin ligase complex (E3) involved in phospho-$I{\kappa}B{\alpha}$ ubiquitination. Upon infection of ileal loops in rabbits, the ospG mutant induced a stronger inflammatory response compared with the wild-type strain, indicating that OspG down-regulates the host innate response induced by invasive bacteria.

• 식물병연구
• /
• 제29권1호
• /
• pp.23-38
• /
• 2023

Erwinia amylovora에 의해 발생하는 화상병은 2015년 국내에서 처음 보고된 이후 전국적으로 확산되고 있다. 화상병은 벌과 같은 화분매개충, 강한 바람을 동반한 강수와 이병주 전정 작업에 의한 전파 등 많은 경로를 통해 병원균 감염이 진행되어 발생한다. 이 외에도 자생하는 개야광나무속, 산사나무속, 피라칸다속, 벚나무속, 마가목속 등의 장미과 식물이 E. amylovora의 기주식물과 전파원이 될 수 있음이 보고되어 있다. 그러나, 국내에서는 아직까지 자생하고 있는 장미과 식물의 화상병 감수성에 관한 연구가 많이 다뤄지지 않은 상황이다. 본 연구에서는 2020년부터 2022년까지 3년간 국내에서 채집한 야생 장미과 식물 10속 25종을 대상으로 화상병 감수성 검정을 진행하였다. 10⁸ cfu/ml 농도의 E. amylovora 균액을 이용하여 채집한 식물의 꽃, 잎과 가지, 과실에 접종하고, 화상병 유사 병징 발현을 관찰하고 PCR을 통해 접종 조직 내의 E. amylovora 검출 여부를 분석하였다. 그 결과, 병징 발현과 병원균 검출 결과가 동일한 14종의 야생 장미과 식물을 확인하였다. 이러한 결과는 향후 적절한 화상병 방제 정책 수립에 기여할 수 있을 것으로 생각된다.

• Journal of Microbiology and Biotechnology
• /
• 제17권12호
• /
• pp.2046-2055
• /
• 2007

Wild-type V. vulnificus cannot grow using lactose as the sole carbon source or take up the sugar. However, prolonged culture of this species in media containing lactose as the sole carbon source leads to the generation of a spontaneous lactose-utilizing (LU) mutant. This mutant showed strong ${\beta}$-galactosidase activity, whereas the wild-type strain showed a barely detectable level of the activity. A mutant with a lesion in a gene homologous to the lacZ of E. coli in the bacterium no longer showed ${\beta}$-galactosidase activity or generated spontaneous LU mutants, suggesting that the lacZ homolog is responsible for the catabolism of lactose, but the expression of the gene and genes for transport of lactose is tightly regulated. Genetic analysis of spontaneous LU mutants showed that all the mutations occur in a lacI homolog, which is located downstream to the lacZ and putative ABC-type lac permease genes. Consistent with this, a genomic library clone containing the lad gene, when present in trans, made the spontaneous LU mutants no longer able to utilize lactose as the sole carbon source. Taken together with the observation that excessive amounts of exogenously supplemented possible catabolic products of lactose have negative effects on the growth and survivability of V. vulnificus, we suggest that V. vulnificus has evolved to carry a repressor that tightly regulates the expression of lacZ to keep the intracellular toxic catabolic intermediates at a sublethal level.

• Molecules and Cells
• /
• 제37권10호
• /
• pp.727-733
• /
• 2014

Spinosyns A and D are potent ingredient for insect control with exceptional safety to non-target organisms. It consists of a 21-carbon tetracyclic lactone with forosamine and tri-Omethylated rhamnose which are derived from S-adenosyl-methionine. Although previous studies have revealed the involvement of metK1 (S-adenosylmethionine synthetase), rmbA (glucose-1-phosphate thymidylyltransferase), and rmbB (TDP-D-glucose-4, 6-dehydratase) in the biosynthesis of spinosad, expression of these genes into rational screened Saccharopolyspora spinosa (S. spinosa MUV) has not been elucidated till date. In the present study, S. spinosa MUV was developed to utilize for metabolic engineering. The yield of spinosyns A and D in S. spinosa MUV was $244mgL^{-1}$ and $129mgL^{-1}$, which was 4.88-fold and 4.77-fold higher than that in the wild-type ($50mgL^{-1}$ and $27mgL^{-1}$), respectively. To achieve the better production; positive regulator metK1-sp, rmbA and rmbB genes from Streptomyces peucetius, were expressed and co-expressed in S. spinosa MUV under the control of strong $ermE^*$ promoter, using an integration vector pSET152 and expression vector pIBR25, respectively. Here-with, the genetically engineered strain of S. spinosa MUV, produce spinosyns A and D up to $372/217mgL^{-1}$ that is 7.44/8.03-fold greater than that of wild type. This result demonstrates the use of metabolic engineering on rationally developed high producing natural variants for the production.

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
• /
• pp.85.1-85
• /
• 2003

In most ascomycetes, a single mating type locus, MAT, with two alternate forms (MAT1-1 and MAT1-2) called idiomorphs, controls mating ability. In heterothallic ascomycetes these alternate idiomorphs reside in different nuclei. In contrast, most homothallic ascomycetes carry both MAT1-1 and MAT1-2 in a single nucleus, usually closely linked. An example of the latter is Gibberella zeae, a producer of mycotoxins such as trichothecene and zearalenone that threaten human and animal health. We asked if G. zeae could be made strictly heterothallic by manipulation of MAT. Targeted gene replacement was used to differentially delete MAT1-1 or MAT1-2 from a wild type haploid MAT1-1 MAT1-2 strain, resulting in MAT1-1；mat1-2, mat1-1；MAT1-2 strains that were self-sterile, yet able to cross to wild type testers and more importantly, to each other. These results indicated that differential deletion of MAT idiomorphs eliminates selfing ability of G. zeae, but the ability to outcross is retained. To our knowledge, this is the first report of complete conversion of fungal reproductive strategy from homothallic to heterothallic by targeted manipulation of MAT. Practically, this approach opens the door to simple and efficient procedures for obtaining sexual recombinants of G. zeae that will be useful for genetic analyses of mycotoxin production and other traits, such as ability to cause disease.

• 미생물학회지
• /
• 제46권1호
• /
• pp.93-95
• /
• 2010

리그닌 분해효소 군을 가진 백색부후균들은 다핵방향족 화합물을 포함하여 염료와 폭약 및 내분비장애 물질의 분해 등 다양한 난분해성 물질을 분해할 수 있다. 리그닌 분해효소 중 laccase와 manganese peroxidase (MnP)를 각각 발현하는 벡터를 국내에서 분리한 백색부후균류의 하나인 아교버섯(Phlebia tremellosa)에 형질전환 방법으로 도입시킨 형질전환체를 사용하여 염료의 탈색능력을 분석하였다. Methyl green의 경우 3일 후 약 50%의 탈색을 보인 야생형에 비하여 laccase 형질전환체(TF2-1)와 MnP 형질전환체(T5) 모두 90% 이상의 탈색을 보였다. Remazol brilliant blue R (RBBR)에서는 야생형이 약 67%의 탈색을 보인 반면 두 가지 형질전환체들은 약 85%의 탈색을 보였다. 각각의 형질전환체들은 laccase와 MnP의 활성 및 유전자 발현도 활발한 것으로 확인되었다.

• BMB Reports
• /
• 제28권3호
• /
• pp.265-270
• /
• 1995

Acetolactate synthase (ALS, EC 4.1.3.18) is the first common enzyme in the biosynthesis of leucine, isoleucine, and valine. It is the target enzyme for several classes of herbicides, including the sulfonylureas, the imidazolinones, the triazolopyrimidines, the pyrimidyl-oxy-benzoates and the pyrimidyl-thio-benzens. The sulfonylurea-resistant ALS gene (SurB) from Nicotiana tabaccum [Lee et al. (1988) The EMBO J. 7, 1241-1248] was cloned into the bacterial expression plasmid pT7-7. The resulting recombinant plasmid pT7-ALS was used to transform an ALS-deficient Escherichia coli strain MF2000. MF2000 cells transformed with pT7-ALS grew in the absence of valine and isoleucine. ALS activities of 0.042 and 0.0002 ${\mu}mol/min/mg$ protein were observed in the crude extracts prepared from MF2000 cells transformed with plasmids pT7-ALS and pT7-7, respectively. In addition, the former crude extract containing mutant ALS was insensitive to inhibition by K11570, a new chemical class of herbicides. $IC_{50}$ values for K11570 were $0.13{\pm}0.01$ mM. For comparison, a plasmid pTATX containing the wild-type Arabidopsis thaliana ALS coding sequences was also expressed in MF2000. ALS activities of 0.037 ${\mu}mol/min/mg$ protein were observed, and the wild type ALS was sensitive to two different classes of herbicides, K11570 and ALLY, a sulfonylurea. $IC_{50}$ values for K11570 and ALLY were $0.63{\pm}0.07$ and $80{\pm}5.6$ nM, respectively. Thus, the results suggest that the sulfonylurea-resistant tobacco ALS was functionally expressed in the bacteria, and that K11570 herbicides bind to the regulatoty site of ALS enzymes.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제11권1호
• /
• pp.37-42
• /
• 2005

We cloned the $\beta$-tubulin genes from the wild type strain and two benomyl-resistant mutants of Metahizium anisopliae and determined their nucleotide sequences. A $\beta$-tubulin encoding 448-residue protein from wild type M. anisopliae shows strong homology to other $\beta$-tubulins. The coding region is interrupted by four introns. Comparisons of intron position between the M. anisopliae gene and other fungal $\beta$-tubulin genes show considerable positional conservation. The mutations responsible for benomyl resistance were determined in two spontaneous mutants, 8-18 and 8­19. One mutant 8-18 substituted glutamate for aspar­agine at position 33 and lysine for glutamine at position 134. The other mutant 8-19 showed alterations at three positions of $\beta$-tubulin arginine for tryptophan at position 21, lysine for asparagine at position 33, and phenylalanine for leucine at position 240. These data suggest that regions of $\beta$-tubulin containing amino acids 21, 33,134, and 240 interact to form the binding site of benomyl.