• Journal of Marine Life Science
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• v.8 no.1
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• pp.56-67
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• 2023

Marine macroalgae are important in coastal ecosystems and interact with marine microorganisms. In this study, we isolated fungi from seven types of marine macroalgae including Cladophora sp., Gloiopeltis furcate, Gracilariopsis chorda, Hydroclathrus clathratus, Prionitis crispata, Sargassum micracanthum, and Ulva lactuca collected in Korea. Morphological and phylogenetic analyses identified the isolates as four Aspergillus spp. (A. fumigatus, A. sydowii, A. tamarii, and A. terreus), three Penicillium spp. (P. crustosum, P. jejuense, and P. rubens), and Cladosporium tenuissimum. Among them, A. fumigatus TOP-U2, A. tamarii SH-Sw5, and A. terreus GJ-Gf2 strains showed the activities of all enzymes examined (amylase, chitinase, lipase, and protease). Based on the enzymatic index (EI) values in solid media, A. terreus GJ-Gf2 and C. tenuissimum UL-Pr1 exhibited the highest amylase and lipase activities, respectively. Chitinolytic activity was only observed in A. terreus GJ-Gf2, A. tamarii SH-Sw5, and A. fumigatus TOP-U2. Penicillium crustosum UL-Cl2 and C. tenuissimum UL-Pr1 showed the highest protease activities. To the best of our knowledge, this is the first report of lipolytic and proteolytic activities in a marine-derived C. tenuissimum strain. Overall, the fungal strains isolated from the marine macroalgae in this study actively produced industrially important enzymes.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.262-269
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• 2013

The object of this study was to improve the quality of Cheonggukjang with new starter, Bacillus subtilis BC-P1. Twenty strains were isolated from the commercial cheonggukjang and 1 Bacillus strain (BC-P1) with protease activity was selected. The 16S rRNA gene sequence revealed that the BC-P1 was closely related to B. subtilis with 99% homology. The quality characteristics of chunggukjang fermented with B. subtilis BC-P1, Bacillus nato (PC) and commercial chunggukjang (NC) were investigated. The characteristics of fermentation were determined by protease, lipase, xylanase, chitinase, and fibrinolytic activities, reducing sugar, nutrient composition and amino acid contents of cheonggukjang sample. Cheonggukjang fermented with B. subtilis BC-P1 showed the strongest fibrinolytic, xylanase, and chitinase activities. Reducung sugar contents of Cheonggukjang samples were $30.16{\pm}2.11$ mg/g (NC), $28.56{\pm}1.52$ mg/g (PC), $32.39{\pm}1.87$ mg/g (BC-P1). And their total amino acid contents were 338.99 mg% (NC), 445.19 mg% (PC), 741.35 mg% (BC-P1). These results suggested that B. subtilis BC-P1 was suitable to be used as a starter to enhance the quality and effects of cheonggukjang.

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.50-53
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• 2002

The optimum temperature and pH for mycelial growth of B. bassiana DGUM 34001 were $24^{\circ}C$ and pH 7.0, respectively. Among the complex media used, mushroom complex medium (MCM) was the most favorable for mycelial growth. When Czapek-Dox medium was used as a minimal medium, glucose was an excellent source for carbon and energy. Soytone and sodium phosphate were favorable constituent for culture medium as a source of organic nitrogen and phosphorus, respectively. When the fungus was grown in MCM broth, the specific activity of extracellular enzyme of ${\alpha}$-amylase, lipase, chitinase, CMCase and pretease were 297.0, 0.058, 0.33, 0.21 and 22.8 units/mg protein, respectively. When various sources of organic nitrogen and chitin were supplemented to determine the production of enzymes, casein and soluble chitosan enhanced the production of extracellular protease and chitinase.

• Mycobiology
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• v.29 no.3
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• pp.173-175
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• 2001

The fruit body of Ramaria botrytis DGUM 29001 was used to determine enzyme activities of fruit body. The specific activity of laccase was the highest(6.5 unit/mg$\cdot$protein) and that of $\alpha$-amylase and xylanase was relatively high. However, little or no enzyme activity of $\beta$-glucosidase, CMCase, exo-$\beta$-1,4-glucanase, chitinase, lipase and protease was found.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1361-1368
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• 2007

Endophytic bacteria associated with the roots of coastal sand dune plants were isolated, taxonomically characterized, and tested for their plant growth-promoting activities. Ninety-one endophytic bacterial isolates were collected and assigned to 17 different genera of 6 major bacterial phyla based on partial 16S rDNA sequence analyses. Gammaproteobacteria represented the majority of the isolates (65.9%), and members of Pseudomonas constituted 49.5% of the total isolates. When testing for antagonism towards plant pathogenic fungi, 25 strains were antagonistic towards Rhizoctonia solani, 57 strains were antagonistic towards Pythium ultimum, 53 strains were antagonistic towards Fusarium oxysporum, and 41 strains were antagonistic towards Botrytis cinerea. Seven strains were shown to produce indole acetic acid (IAA), 33 to produce siderophores, 23 to produce protease, 37 to produce pectinase, and 38 to produce chitinase. The broadest spectra of activities were observed among the Pseudomonas strains, indicating outstanding plant growth-promoting potential. The isolates from C. kobomugi and M. sibirica also exhibited good plant growth-promoting potential. The correlations among individual plant growth-promoting activities were examined using phi coefficients, and the resulting data indicated that the production of protease, pectinase, chitinase, and siderophores was highly related.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.66-73
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• 2012

Plant growth promoting traits like production of indoleacetic acid (IAA), ammonia, hydrogen cyanide (HCN), siderophore, and like the enzyme activities of catalase, ACC deaminase, cellulase, chitinase and protease were assayed in vitro for twenty one phosphorus solubilizing bacteria isolated from soil isolates. Except SPP-5 and SPP-15 strains, all the other isolated strains produced IAA in various amounts of 10 to $23{\mu}g\;ml^{-1}$. All strains showed positive response for ammonia production and ACC deaminase activity implying that they are capable of growing in a N-free basal medium. Catalase activity was found to be superior in SPP-2, SPP-7, SPP-12 and SPP-17 compared to the other strains tested. HCN production was detected by 15 strains and among them SPP-9, SPP-15, SAph-11, and SAph-24 were found to be strong HCN producers. Except the isolates SPP-10, SPP-12, SPP-13 and SPP-14, all the other isolates produced more than 80% siderophore units. None of the strains showed cellulose and chitinase activity. SAph-8, SAPh-11, SAPh-24 and SPP-15 strains showed 35.84, 50.33, 56.64 and 34.78 U/ml protease activities, respectively. SPP-1, SPP-2, SPP-3, SPP-11, SPP-17, SPP-18, SAph-11 and SAph-24 strains showed positive response for all the tested plant growth promotion traits except cell wall degrading enzyme activities. According to the results, all the tested phosphorus solubilizing isolates could exhibit more than three or four plant growth promoting traits, which may promote plant growth directly or indirectly or synergistically. Therefore, these phosphorus solubilizing strains could be employed as bio-inoculants for agriculture soils.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.130-136
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• 2011

Five strains of Actinomyces were isolated from freshwater sponges, Baikalospongia and Lubomirskia, in Lake Baikal. By 16S rRNA sequencing, isolates were identified as Streptomyces griseoplanus, S. halstedii, S. violascens, S. flavovirens, and S. microflavus. Isolates had different characteristics of growth temperature, carbon utilization, enzyme activity, and cellular fatty acid composition. Optimum growth conditions of isolates were $30-37^{\circ}C$, pH 8-9, and 0-1.5% salt concentrations. Major fatty acid compositions were anteiso-$C_{15:0}$, iso-$C_{15:0}$, and iso-$C_{16:0}$. Strain ATS-BA-19 had DNase and chitinase activities and strain ATS-BA-16 had cellulase and protease activities. Colonies of strain ATS-BA-15 and ATS-BA-19 made inhibition zone of Pseudomonas aeruginosa.

• The Korean Journal of Malacology
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• v.27 no.1
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• pp.9-14
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• 2011

This study was examined digestive enzyme activity in the crystalline style of the three species of bivalves. Bivalves used in this study were Tegillarca granosa (n=61), Mytilus galloprovincialis (n=30) and Saxidomus purpuratus (n=30) and collected from southern coast of Korea on May 2010. Digestive enzymes activities in the crystalline style were assayed in spectrophotometer. Amylase and cellulase occupied approximately 90% of digestive enzyme in crystalline style of T. granosa, M. galloprovincialis, and S. purpuratus. And protease activity in crystalline style of T. granosa, M. galloprovincialis and S. purpuratus showed the lowest values to 0.02, 0 and 0.08%, respectively. Digestive enzyme activity in crystalline style of three species was measured in the order of cellulase > amylase > chitinase > laminarinase.

• Journal of Microbiology and Biotechnology
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• v.24 no.1
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• pp.1-7
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• 2014

The possibility of using hyphomycete fungi as suitable biocontrol agents against greenhouse whitefly has led to the isolation of various insect pathogenic fungi. Among them is Beauveria bassiana, one of the most studied entomopathogenic fungi. The objective of this study was to use B. bassiana M130 as an insecticidal agent against the greenhouse whitefly. M130 isolated from infected insects is known to be a biocontrol agent against greenhouse whitefly. Phylogenetic classification of M130 was determined according to its morphological features and 18S rRNA sequence analysis. M130 was identified as B. bassiana M130 and showed chitinase (342.28 units/ml) and protease (461.70 units/ml) activities, which were involved in the invasion of the host through the outer cuticle layer, thus killing them. The insecticidal activity was 55.2% in petri-dish test, 84.6% in pot test, and 45.3% in field test. The results of this study indicate that B. bassiana has potential as a biological agent for the control of greenhouse whitefly to replace chemical pesticides.

• Journal of Pharmacopuncture
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• v.26 no.4
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• pp.307-318
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• 2023

Objectives: Bacterial biofilm is regarded as a significant threat to the production of safe food and the arise of antibiotic-resistant bacteria. The objective of this investigation is to evaluate the quorum sensing inhibitory effect of Nepeta curviflora methanolic extract. Methods: The effectiveness of the leaves at sub-inhibitory concentrations of 2.5, 1.25, and 0.6 mg/mL on the virulence factors and biofilm formation of P. aeruginosa was evaluated. The effect of N. curviflora methanolic extract on the virulence factors of P. aeruginosa, including pyocyanin, rhamnolipid, protease, and chitinase, was evaluated. Other tests including the crystal violet assay, scanning electron microscopy (SEM), swarming motility, aggregation ability, hydrophobicity and exopolysaccharide production were conducted to assess the effect of the extract on the formation of biofilm. Insight into the mode of antiquorum sensing action was evaluated by examining the effect of the extract on the activity of N-Acyl homoserine lactone (AHL) and the expression of pslA and pelA genes. Results: The results showed a significant attenuation in the production of pyocyanin and rhamnolipid and in the activities of protease and chitinase enzymes at 2.5 and 1.25 mg/mL. In addition, N. curviflora methanolic extract significantly inhibited the formation of P. aeruginosa biofilm by decreasing aggregation, hydrophobicity, and swarming motility as well as the production of exopolysaccharide (EPS). A significant reduction in AHL secretion and pslA gene expression was observed, indicating that the extract inhibited quorum sensing by disrupting the quorum-sensing systems. The quorum-sensing inhibitory effect of N. curviflora extract appears to be attributed to the presence of kaempferol, quercetin, salicylic acid, rutin, and rosmarinic acid, as indicated by LCMS analysis. Conclusion: The results of the present study provide insight into the potential of developing anti-quorum sensing agents using the extract and the identified compounds to treat infections resulting from quorum sensing-mediated bacterial pathogenesis.