• Applied Biological Chemistry
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• v.35 no.3
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• pp.191-195
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• 1992

In order to elucidate the plant-microorganism relationship, we purified an ethylene-inducible, basic 30 KD endochitinase from bean leaves and studied its antifungal activity by a hyphal extension-inhibition assay. The purified chitinase was effective in the inhibition of hyphal growth of Aspergillus fumigatus, Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani, while microbial chitinases of Serratia marcescens and Streptomyces griceus, egg white lysozyme and papya protease didn't affect hyphal growth of the fungi. The chitinase degraded the cell walls of Micrococcus lysodeikticus, suggesting the lysozyme activity of the chitinase. We discussed the implication of the bifunctional chitinase/lysozyme activities of the protein with hydrolysis of chitin in the rapidly extending hyphae of the fungi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.760-763
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• 2001

Five commercial salt-fermented shrimps contained 29.8~48.3% of salt 3.5%~7.3% of total nitrogen and 0.3~0.7g/100g of amino-nitrogen respectively. The average peptide length(APL) of five commercial salt-fermented shrimps ranged from 10.1 to 15.0. Sample B and E showed longer APL than the others with the values of 15.0 and 14.4 respectively. Protease activity showed the large differences in five samples from 17 unit to 232 unit ; sample C showed the highest protease activity with 232 unit while sample D and E were relatively lower with 17 unit and 18 unit respectively. The chitinase activities which can hydrolyze chitin the one of components on outer layer of shrimp ranged from 14.4 unit to 171 unit. Sample E had the highest chitinase activity as 171 unit but sample B showed the lowest activity with 14.4 unit. Chitooligosaccharides of five commercial salted-fermented shrimps were consisted of monoglucosamine diglucosamine and triglucosamine.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.230-231
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• 2004

The mycelia of Sparassis crispa DSMZ 5201 were cultivated at $24^{\circ}C$ for 15 days in yeast-malt extract-glucose broth (pH 4.0) and the filtrate was used as crude enzyme solution to determined the extracellular enzyme activity. The specific activity of $\alpha$-amylase was 44.27 unit/protein. The specific activities of protease, CMCase, $\beta$-glucosidase, chitinase, exo-$\beta$-l,4-glucanase were relatively high. However, a very little activity of xylanase was found.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1001-1005
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• 2010

The chitinase-producing strain TKU008 was isolated from soil in Taiwan, and it was identified as a new species of Pseudomonas. The culture condition suitable for production of chitinase was found to be shaking at $30^{\circ}C$ for 4 days in 100 ml of medium containing 1% shrimp and crab shell powder, 0.1% $K_2HPO_4$, and 0.05% $MgSO_4{\cdot}7H_2O$ (pH 7). The TKU008 chitinase was suppressed by the simultaneously existing protease, which also showed the maximum activity at the fourth day of incubation. The molecular mass of the chitinase was estimated to be 40 kDa by SDS-PAGE. The optimum pH, optimum temperature, pH stability, and thermal stability of the chitinase were pH 7, $50^{\circ}C$, pH 6-7, and <$50^{\circ}C$, respectively. The chitinase was completely inhibited by $Mn^{2+}$ and $Cu^{2+}$. The results of peptide mass mapping showed that 11 tryptic peptides of the chitinase were identical to the chitinase CW from Bacillus cereus (GenBank Accession No. gi 45827175) with a 32% sequence coverage.

• Mycobiology
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• v.45 no.4
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• pp.385-391
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• 2017

The ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, ${\beta}$-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata, Macrophomina sp., Colletotrichum gloeosporioides, Botrytis cinerea, and Sclerotium rolfesii. The B. subtilis ALICA detected positive for chitinase, ${\beta}$-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, ${\beta}$-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.265-276
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• 2023

This study aimed to isolate and characterize fungi from freshwater environments in South Korea and evaluate their extracellular enzyme activities. Fungal strains were collected from various freshwater sources and identified using phylogenetic analysis. The isolated fungi included known aquatic hyphomycetes and previously unreported species. Extracellular enzyme, including those of protease, amylase, lipase, cellulase, laccase, and chitinase, activities were evaluated. Among the isolated strains, several showed high enzyme activity, suggesting their potential role in organic matter decomposition in freshwater ecosystems. This research expands our knowledge of the diversity and enzyme activities of the fungi in freshwater environments, contributing to our understanding of their ecological roles.

• The Plant Pathology Journal
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• v.22 no.4
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• pp.323-328
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• 2006

Serratia marcescens W1, isolated from cucumber-cultivated soil in Suwon, Korea, evidenced profound antifungal activity and produced the extracellular hydrolytic enzymes, chitinase and protease. In order to isolate the antifungal genes from S. marcescens W1, a cosmid genomic library was constructed and expressed in Escherichia coli. Transformants exhibiting chitinase and protease expression were selected, as well as those transformants evidencing antifungal effects against the rice blast fungus, Magnaporthe grisea, and the cucumber leaf spot fungus, Cercospora citrullina. Cosmid clones expressing chitinase or protease exerted no inhibitory effects against the growth of fungal pathogens. However, two cosmid clones evidencing profound antifungal activities were selected for further characterization. An 8.2 kb HindIII fragment from these clones conditioned the expression of antagonistic activity, and harbored seven predicted complete open reading frames(ORFs) and two incomplete ORFs. The deduced amino acid sequences indicated that six ORFs were highly homologous with genes from S. marcescens generating pyrroloquinoline quinone(PQQ). Only subclones harboring the full set of pqq genes were shown to solubilize insoluble phosphate and inhibit fungal pathogen growth. The results of this study indicate that the functional expression of the pqq genes of S. marcescens W1 in E. coli may be involved in antifungal activity, via as-yet unknown mechanisms.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.439-445
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• 2012

The chitinase producing Lysobacter enzymogenes C-3 has previously been shown to suppress plant pathogens in vitro and in the field, but little is known of the regulation of chitinase production, or its role in antimicrobial activity and biocontrol. In this study, we isolated and characterized chitinase-defective mutants by screening the transposon mutants of L. enzymogenes C-3. These mutations disrupted genes involved in diverse functions: glucose-galactose transpoter (gluP), disulfide bond formation protein B (dsbB), Clp protease (clp), and polyamine synthase (speD). The chitinase production of the SpeD mutant was restored by the addition of exogenous spermidine or spermine to the bacterial cultures. The speD and clp mutants lost in vitro antifungal activities against plant fungal pathogens. However, the gluP and dsbB mutants showed similar antifungal activities to that of the wild-type. The growth of the mutants in nutrient rich conditions containing chitin was similar with that of the wild-type. However, growth of the speD and gluP mutants was defective in chitin minimal medium, but was observed no growth retardation in the clp and dsbB mutant on chitin minimal medium. In this study, we identified the four genes might be involved and play different role in the production of extracellular chitinase and antifungal activity in L. enzymogenes C-3.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.117-126
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• 2010

A chitinase (CHT) and a protease (PRO) were purified from the culture supernatant of Serratia sp. TKU017, with shrimp shell as the sole carbon/nitrogen source. The molecular masses of CHT and PRO determined by SDS-PAGE were approximately 65 kDa and 53 kDa, respectively. CHT was inhibited by $Mn^{2+}$ and $Cu^{2+}$, and PRO was inhibited by most tested divalent metals and EDTA. The optimum pH, optimum temperature, pH stability, and thermal stability of CHT and PRO were pH 5, $50^{\circ}C$, pH 5-7, and <$50^{\circ}C$, and pH 9, $40^{\circ}C$, pH 5-11, and <$40^{\circ}C$, respectively. PRO retained 95% of its protease activity in the presence of 0.5 mM SDS. The result demonstrates that PRO is an SDS-resistant protease and probably has a rigid structure. The $4^{th}$-day supernatant showed the strongest antioxidant activity (70%, DPPH scavenging ability) and the highest total phenolic content ($196{\pm}6.2\;{\mu}g$ of gallic acid equiv./ml). Significant associations between the antioxidant potency and the total phenolic content, as well as between the antioxidant potency and free amino groups, were found for the supernatant. With this method, we have shown that shrimp shell wastes can be utilized and it is effective in the production of enzymes and antioxidants, facilitating its potential use in industrial applications and functional foods.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.330-337
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• 1993

A bacterium, pathogenic to Nilaparvata lugens Stal. causing high mortality in 3~5 days, were selected and identified as Serratuz marcescens biotype A2a which is not a nosocomlally infective strain. In order to determine the characters of Serratia marcesce'1lS associated with insect pathogenicity, Tn5 mutagenesis was carried out by conjugating with E. coli pJB4J1. Transconjugants were plate-assayed for missing chitinase, protease and DNase activity. A protease negative mutant was selected for missing JOseet pathogenicity. SEM and TEM revealed the presence of bacterial cells in the epithelial tissue of inner abdomal tissue of the hypodermic layer of abdomen. Such a colonization was limmited to the subjacent tissue inside the intacL cuticular epidermis. These observation supported our result of pathogenicity tests of transconjugants.