• 식물병연구
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• 제20권3호
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• pp.216-218
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• 2014

Lysobacter antibiocus HS124 is a chitinase-producing rhizobacterium with proven capacities to suppress plant diseases. Bacterial cultures of L. antibioticus HS124 showed strong biocontrol efficacies against various plant diseases compared to those of bacterial cultures of Bacillus subtilis QST713 which is an active ingredient of a commercial biopesticide, Serenade. Here, we report the draft genome sequence and automated annotation of strain HS124. This draft genome sequence indicates the novelty of L. antibiocus HS124 and a subset of gene functions that may be related to its biocontrol activities.

• 생명과학회지
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• 제13권3호
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• pp.355-358
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• 2003

식물 병원성 진균인 Rhizoctonia solani에 대한 길항능이 있는 Trichoderma 계열의 미생물 균주를 선별하였다. R. solani의 성장을 저해하는 능력이 우수한 균주를 선별하기 위하여 일차적으로 PDA 평판에서 inhibition zone을 측정하였고, 병원성 진균의 세포벽을 용해시킬 수 있는 세포외 효소인 glucanase 및 chitinase 활성을 분석하였다. 4∼5 mm 이상의 inhibition zone을 보여주었고, glucanase 및 chitinase 활성이 우수한 Trichoderma sp. UK-3와 T. viride 균주들을 선별할 수 있었다.

• Plant Biotechnology Reports
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• 제3권2호
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• pp.147-155
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• 2009

Oryza grandiglumis Chitinase IVa (OgChitIVa) cDNA encoding a class IV chitinase was cloned from wild rice (Oryza grandiglumis). OgChitIVa cDNA contains an open reading frame of 867 nucleotides encoding 288 amino acid residues with a predicted molecular weight of 30.4 kDa and isoelectric point of 8.48. Deduced amino acid sequences of OgChitIVa include the signal peptide and chitin-binding domain in the N-terminal domain and conserved catalytic domain. OgChitIVa showed significant similarity at the amino acid level with related monocotyledonous rice and maize chitinase, but low similarity with dicotyledoneous chitinase. Southern blot analysis showed that OgChitIVa genes are present as two copies in the wild rice genome. It was shown that RNA expression of OgChitIVa was induced by defense/stress signaling chemicals, such as jasmonic acid, salicylic acid, and ethephon or cantharidin and endothall or wounding, and yeast extract. It was demonstrated that overexpression of OgChitIVa in Arabidopsis resulted in mild resistance against the fungal pathogen, Botrytis cinerea, by lowering disease rate and necrosis size. RT-PCR analysis showed that PR-1 and PR-2 RNA expression was induced in the transgenic lines. Here, we suggest that a novel OgChitIVa gene may play a role in signal transduction process in defense response against B. cinerea in plants.

• Applied Biological Chemistry
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• 제34권1호
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• pp.54-60
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• 1991

식물 병원성 사상균 세포벽의 주성분인 chitin을 분해하는 미생물을 토양에서 분리, 선발하여 동정하고 이들의 효소적 성질을 조사하였다. 선발균 Serratia (S) marcescens는 식물 병원성 사상균인 Fusarium (F) axysporum과 Rhizoctomia (R) solani에 대해 길항력은 갖고 있었으며 효소적으로 chitinase 외에 laminarinase 및 protease 등의 활성을 가지고 있었다. 선발 균주의 chitinase 생산 최적조건은 chitin broth 기본배지의 조성과 온도 및 배양시간을 변형하여 조사한 결과 colloidal chitin 1.5%, tryptone 0.5%, glucose 1%, peptone 0.2%, $MgSO_4{\cdot}7H_2O\;0.1%,\;K_2HPO_4\;0.1%,\;NaCl\;0.1%$ (w/v), pH 6.8 배지에서 $30^{\circ}C$, 72시간 배양하였을 때이었으며 효소의 in vitro 최적 활성조건은 pH 7.5, $50^{\circ}C$이었다. 한편 여러 무기이온 중에서 $Ag^+$와 $Mn^{++}$은 효소의 활성을 촉진시켰다.

• 한국미생물·생명공학회지
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• 제6권4호
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• pp.149-153
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• 1978

1) 토양에서 분리한 Streptomyces 속중에 chitinase를 강하게 분비하는 균 일주를 분리선별하여 그 효소학적 성질 및 생성조건을 조사하였다. 2) 3$0^{\circ}C$에서 진탕배양하면서 경시적으로 본효소 생산을 조사한 바 45시간만에 최대 생산을 보였으며 또한 배지내에 glucose를 0.375% 첨가하였을 때 효소생산이 최대에 달하였으며 그 이상의 농도에서는 효소생산에 오히려 조해현상이 일어났다. 3) 본효소의 최적 pH는 7.0, 최적온도는 5$0^{\circ}C$ 였으며 pH 6.5~8.0에서 비교적 안정하였고 7$0^{\circ}C$에서 20분간 열처리에서도 안정하였다. 4) 금속 이온에 대한 영향은 Co$^{2+}$ 에 의해 활성화 되었고 Hg$^{2+}$, Ni$^{2+}$, Pb$^{2+}$ 등 중금속인 경우 $10^{-2}$ M 정도의 고농도에서 약 50%정도 실활하였다. 또한 본효소는 Aspergillus oryzae에 대해서도 비교적 강하게 작용하였다.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1169-1175
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• 2009

An antifungal chitinase, ChiCW, produced by Bacillus cereus 28-9 is effective against conidial germination of Botrytis elliptica, the causal agent of lily leaf blight. ChiCW as a modular enzyme consists of a signal peptide, a catalytic domain, a fibronectin type-III-like domain, and a chitin-binding domain. When two C-terminal domains of ChiCW were truncated, $ChiCW{\Delta}FC$ (lacking the chitin-binding domain and fibronectin type III-like domain) lost its antifungal activity. Since $ChiCW{\Delta}C$ (lacking the chitin-binding domain) could not be expressed in Escherichia coli as $ChiCW{\Delta}FC$ did, a different strategy based on protein engineering technology was designed to investigate the involvement of the chitin-binding domain of ChiCW ($ChBD_{ChiCW}$) in antifungal activity in this study. Because ChiA1 of Bacillus circulans WL-12 is a modular enzyme with a higher hydrolytic activity than ChiCW but not inhibitory to conidial germination of Bo. elliptica and the similar domain composition of ChiA1 and ChiCW, the C-terminal truncated derivatives of ChiA1 were generated and used to construct chimeric chitinases with $ChBD_{ChiCW}$. When the chitin-binding domain of ChiA1 was replaced with $ChBD_{ChiCW}$, the chimeric chitinase named ChiAAAW exhibited both high enzyme activity and antifungal activity. The results indicate that $ChBD_{ChiCW}$ may play an important role in the antifungal activity of ChiCW.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1312-1321
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• 2011

Enzyme extracts of cellulase [filter paper cellulase (FPase) and carboxymethyl cellulase (CMCase)], chitinase, and chitosanase produced by Aspergillus niger NRRL-567 were evaluated. The interactive effects of initial moisture and different inducers for FP cellulase and CMCase production were optimized using response surface methodology. Higher enzyme activities [FPase $79.24{\pm}4.22$ IU/gram fermented substrate (gfs) and CMCase $124.04{\pm}7.78$ IU/gfs] were achieved after 48 h fermentation in solid-state medium containing apple pomace supplemented with rice husk [1% (w/w)] under optimized conditions [pH 4.5, moisture 55% (v/w), and inducers veratryl alcohol (2 mM/kg), copper sulfate (1.5 mM/kg), and lactose 2% (w/w)] (p<0.05). Koji fermentation in trays was carried out and higher enzyme activities (FPase $96.67{\pm}4.18$ IU/gfs and CMCase $146.50{\pm}11.92$ IU/gfs) were achieved. The nonspecific chitinase and chitosanase activities of cellulase enzyme extract were analyzed using chitin and chitosan substrates with different physicochemical characteristics, such as degree of deacetylation, molecular weight, and viscosity. Higher chitinase and chitosanase activities of $70.28{\pm}3.34$ IU/gfs and $60.18{\pm}3.82$ to $64.20{\pm}4.12$ IU/gfs, respectively, were achieved. Moreover, the enzyme was stable and retained 92-94% activity even after one month. Cellulase enzyme extract obtained from A. niger with chitinolytic and chitosanolytic activities could be potentially used for making low-molecular-weight chitin and chitosan oligomers, having promising applications in biomedicine, pharmaceuticals, food, and agricultural industries, and in biocontrol formulations.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.865-871
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• 2002

A bacterium having strong chitinolytic activity on $0.2\%$ colloidal chitin-containing agar medium was isolated from coastal soil in Korea. Based on the nucleotide sequence of conserved segment of a 165 rRNA gene, the bacterium was identified as Paenibacillus illinoisensis KJA-424. The population of P. illinoisensis KJA-424 and chitinase activity significantly increased for the first 2 days of incubation. On SDS-PACE analysis with $0.01\%$ glycol chitin, three protein bands (63, 54, and 38 kDa) with chitinolytic activity were detected tooted. The effect of P illinoisensis KJA-424 on the egg hatch of root-knot nematode (Meloidogyne incognita) was investigated. After 7 days of incubation with the chitinase-producing P. illinoisensis KJA-424, none of the eggs hatched, whereas a $39.8\%$ egg hatching rate was observed in the water control. Inverted and scanning electron microscopic observations demonstrated that P. illinoisensis KJA-424 deformed and destroyed the eggshell of M. incognita. In conclusion, chitinase-produced by p. illinoisensis KJA-424 caused the lysis of M. incognita eggshell and resulted in the inhibition of egg hatching in vitro.

• 식물조직배양학회지
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• 제26권3호
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• pp.177-182
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• 1999

Chitinase 유전자가 삽입된 감자 Belchip 품종의 형질전환체와 대조구에 곰팡이 병원균을 접종하였다. 7개 계통의 형질전환식물체를 12cm정도 키운 후 병원균인 Phytophthora infestans의 zoospore를 접종하여 인공적으로 역병을 유발시켰다. 그 결과 발병율에 따라서 세 그룹으로 분리되었는데 대조구에 비하여 감염 정도가 심한 것 2개 계통. 비슷한 3개 계통, 발병 정도가 약한 2개 계통으로 구분되었다. 대조구에 비하여 저항성이 높았던 2개 계통과 발병이 심했던 1개 계통만을 대상으로 하여 2차실험을 실시한 결과, 1차실험과 비슷한 경향을 나타냈다. 포장에서 생육된 2개의 저항성 계통은 자연적으로 발생한 역병에 대해서도 역시 대조구에 비하여 역병저항성이 더 높았다.

• 미생물학회지
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• 제38권1호
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• pp.50-53
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• 2002

백강균(Beauveria bassiana DGUM 34001)은 $24^{\circ}C$의 온도와pH 7.0의 초기 pH에서 최적의 균사체 생육을나타내었다. 사용한 복합배지 중 mushroom complex배지(MCM)에서 가장 우수한 균사생육을 나타내었다. Czapek-Dox 한천배지를 최소배지로 각각 탄소원, 질소원 및 인산원의 영향을 조사한 결과, glucose, soytone 및 sodium phosphate ($NaH_2$$PO_4$)에서 가장 우수한 균사 생육을 보여주었다. MCM액체배지에서 균사 배양 후 세포외 효소 활성을 측정한 결과,$\alpha$-amylase, lipase, chitinase, CMCase및 pretense의 비효소활성은 각각 297.0, 0.058, 0.33, 0.21 및 22.8 units/mg protein이었다. Casein과 soluble chitosan을 첨가할 경우 세포외 분비 pretense와 chitinase의 효소 활성 이 증가되었다.