• Korean Journal of Poultry Science
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• v.44 no.3
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• pp.181-188
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• 2017

Bacteriophages are viruses that exclusively infect bacterial cells, and lytic bacteriophages can be used as a safe alternative to antibiotics for the prevention and treatment of animal diseases. In this study, we attempted to isolate and characterize bacteriophages for Salmonella enterica serovar Gallinarum (Salmonella Gallinarum), the causative agent of fowl typhoid in chickens. Ten bacteriophages were isolated from samples of sewage from seven poultry slaughterhouses. One of these isolate, designated as $SG{\Phi}-YS$ SP and classified in the family Myoviridae, produced plaques with seven Salmonella Gallinarum strains. However, no plaques were produced with any of the Salmonella enterica serovar Enteritidis strains tested, suggesting that this bacteriophage is Salmonella Gallinarum specific. To assess the lytic ability of $SG{\Phi}-YS$ SP against Salmonella Gallinarum, bacterial growth rates following inoculation of the bacteriophage were compared with the control. The $SG{\Phi}-YS$ SP treatment, with a multiplicity of infection of 10, reduced the growth of Salmonella Gallinarum by 2.21 log cfu/mL at 6 h, and 2.13 log cfu/mL at 9 h, suggesting that this bacteriophage isolate could be used for the prevention or treatment of Salmonella Gallinarum infection in chickens.

• Food Science of Animal Resources
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• v.37 no.2
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• pp.320-328
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• 2017

In this study, two Listeria bacteriophages, LMP1 and LMP7, were isolated from chicken feces as a means of biocontrol of L. monocytogenes. Both bacteriophages had a lytic effect on L. monocytogenes ATCC 7644, 15313, 19114, and 19115. Phages LMP1 and LMP7 were able to inhibit the growth of L. monocytogenes ATCC 7644 and 19114 in tryptic soy broth at $10^{\circ}C$ and $30^{\circ}C$. Nevertheless, LMP1 was more effective than LMP7 at inhibiting L. monocytogenes ATCC 19114. On the contrary, LMP7 was more effective than LMP1 at inhibiting L. monocytogenes ATCC 7644. The morphology of LMP1 and LMP7 resembled that of members of the Siphoviridae family. The growth of L. monocytogenes ATCC 7644 was inhibited by both LMP1 and LMP7 in milk; however, the growth of L. monocytogenes ATCC 19114 was only inhibited by LMP1 at $30^{\circ}C$. The lytic activity of bacteriophages was also evaluated at $4^{\circ}C$ in milk in order to investigate the potential use of these phages in refrigerated products. In conclusion, these two bacteriophages exhibit different host specificities and characteristics, suggesting that they can be used as a component of a phage cocktail to control L. monocytogenes in the food industry.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.304-307
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• 2007

An efficient production method of spirulina extract was developed by enzymatic treatment using cell lytic and proteolytic enzymes. The suitable dosage of Tunicase, a cell lytic enzyme, was found to be 2.0% (w/w). Proteolytic enzymes were screened to obtain high solid recovery and spirulina extraction (SE) index, which indicates nucleic acid-related substances content. Among the seven tested proteases, Esperase was selected and optimal dosage of this enzyme was 2.0% (w/w). The solid recovery and SE index of simultaneous treatment and co-treatment using optimal dosages of Tunicase and Esperase were greatly similar, respectively. However, co-treatment had the effect of shortening total hydrolysis time. The SE index and solid recovery of co-treatment were significantly enhanced by 75% $(11.4{\rightarrow}20.0)$ and 45% $(45.2%{\rightarrow}65.3%)$, respectively, than those of the non-treated extracts.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.595-600
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• 1998

In order to investigate a relationship of the structure-antifungal and hemolytic activities between cecropin A(1-8)-magainin 2(1-12) and cecropin A(1-8)-melittin(1-12) hybrid peptides, several analogues with amino acid substitution at positions 10 (Ile) and 16 (Ser) were designed and synthesized. The increase of the hydrophobicity by substituting with Leu, Phe, and Trp at position 16 in cecropin A(1-8)-magainin 2(1-12) did not have a significant effect on antifungal activity but caused a remarkable increase in hemolytic activity. These results indicate that the hydrophobic property at position 16 of cecropin A(1-8)-magainin 2(1-12) is more correlated to hemolytic activity than to antifungal activity. Replacement with Pro at position 10 of cecropin A(1-8)- magainin 2(1-12) and cecropin A(1-8)-melittin (1-12) caused a remarkable decrease in a-helical contents in the 50% TFE solution and induced a reduction in lytic activity against Aspergillus flavus, and Aspergillus fumigatus. These results demonstrate that flexibility at the central hinge region is essential for lytic activity against fungal cells and $\alpha$-helicity of the peptides.

• The Korean Journal of Mycology
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• v.39 no.2
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• pp.126-130
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• 2011

In the course of search for multifunctional microbial inoculants, three Bacillus strains (BS11-1,BS11-2,BS11-3) with biological control and biofertilizing effects were selected. In this study, their ability for solubilization of insoluble phosphate, production of indole-3-acetic acid (IAA), siderophore, and hydrolytic enzymes, and antagonism against phytopathogenic fungi were estimated. All strains produced IAA and siderophore depending on culture time and produced a visible clear zone on agar plate containing 0.5% carboxylmethyl cellulose as a carbon source. Also, these strains exhibited antifungal activities against phytopathogenic fungi, Botrytis cinerea, Cylindrocarpon destructans, Fusarium oxysporum, Rhizoctonia solani, and Phytophthora capsici.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.185-194
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• 2006

A fungal strain of Trichoderma having strong chitinolytic activity was isolated from field soil enriched with crabshell for several years. Based on 5.8S rRNA, partial 18S, 28S rRNA genes, ITS1, ITS2 sequence analysis and morphological characteristics, the fungus was identified as Trichoderma asperellum and named as Trichoderma asperellum T-5 (TaT-5). The fungus released lytic enzymes such as chitinase and ${\beta}$-1, 3-glucanse, and produced six antifungal substances in chitin broth medium. To demonstrate the protective effect of TaT-5 against damping-off in cucumber plant caused by Rhizoctonia solani, TaT-5 culture broth (TA), chitin medium (CM) and distilled water (DW) were applied to each pot at 10 days after sowing, respectively. Then, the homogenized hyphae of R. solani were infected to each pot at 1 week after TaT-5 inoculation. During experimental period, fresh weight of shoot and root in cucumber plant more increased at TA treatment compared to other treatments. PR-proteins (${\beta}$-1, 3-glucanase and chitinase) activities in cucumber leaves markedly increased at CM and DW treatments, but the activity slightly increased and then decreased at TA treatment at 3 days after infection of R. solani. The activity of PR-proteins activities in cucumber roots at all treatments decreased with time where the degree of decrement was more alleviated at TA treatment than CM and DW. These results suggest that the lytic enzymes (chitinase and ${\beta}$-1, 3-glucanse) and antifungal substances produced by TaT-5 can reduce the pathogenic attack by R. solani in cucumber plants.

• The Plant Pathology Journal
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• v.20 no.3
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• pp.177-183
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• 2004

Phenylacetic acid (PAA) was evaluated for in vitro anti-oomycete activity and in vivo control efficacy against Phytophthora capsici. Microscopic observation revealed that the high level of anti-oomycete activity of PAA (10 $\mu\textrm{g}$/ml) against P. capsici is mainly due to the lytic effect on zoospores. Zoospore lysis began in the presence of 5 u$\mu\textrm{g}$/ml of PAA and most of the zoospores were collapsed at 10 $\mu\textrm{g}$/ml. PAA showed inhibitory activity against the zoospore germination and hyphal growth of P. capsici at the concentration of 50 $\mu\textrm{g}$/ml. In the glasshouse, the protective effect of PAA against Phytophthora blight was high on pepper plants when treated just before inoculation with P. capsici. In the artificially infested field, protection of pepper plants against the Phyto-phthora epidemic was achieved at a considerable level by PAA treatment.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.456-462
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• 1994

Lysozyme-dextran hybrids were prepared by incubated storage at $60^{\circ}C$ and 80% relative humidity for 16 days. The emulsifying properties of the hybrids were about 14 times higher than those of native lysozyme and were about 3 times higher than those of commercial emulsifiers. Lytic activity of the hybrids remained about 83% that of native lysozyme when mesured against Micrococcus lysodeikticus as a substrate. The excellent emulsifying properties of the hybrids were maintained even at pH 3 and were further improved at pH 10. The emulsifying properties of the hybrids were greatly improved by preheating the hybrids at $100^{\circ}C$. In addition the lysozyme-dextran hybrids showed an antimicrobial effect on Gram-negative bacteria.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.105-111
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• 2013

The experiments were carried out to investigate the biocontrol potential of Lysobacter capsici YS1215 on root-knot nematode and to characterize its lytic enzyme activities. L. capsici YS1215 showed chitinase and gelatinase activities on the medium containing 0.5% chitin or 0.5% gelatin as substrates. Cell growth of L. capsici YS1215 was highest at 6 days, and the highest activities of chitinase (4.0 unit $ml^{-1}$) and gelatinase (7.43 unit $ml^{-1}$) were observed on 3 and 5 days after incubation, respectively. To investigate the effect of L. capsici YS1215 on tomato growth and nematode infection, the plants in pot trial were treated with bacterial culture (BC), half of bacterial culture (HBC), only bacterial medium (BM), tap water (TW) and commercial nematicide (CN). HBC treatd plants showed the higher shoot fresh weight and dry weight on $5^{th}$week after incubation while BM, HBC and BC had consistently higher values than TW at $9^{th}$ week. HBC appeared to be the highest shoot fresh length at $9^{th}$ week. Both CN and BC showed lower number of egg mass, root gall, and population of juveniles in soil compared to BC, HBC, BM and TW. These results suggest that L. capsici YS1215 with its strong ability of lytic enzyme production can be one of the most significant candidates for biocontrol agents against root-knot nematodes.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.54-59
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• 2004

$\beta$-Glucan has been efficiently produced with higher yield by the optimization of liquid cultivation conditions. The optimal composition of medium for batch culture was 5% (w/v) of glucose as a carbon source, 0.5% (w/v) of yeast and 0.5% (w/v) of malt extract as a nitrogen source, 0.1% (w/v) of $KH_2PO_4$ and 0.05% (w/v) $MgSO_4{\cdot}7H_2O$, which had been the base medium for determination of other conditions. The set-up conditions are pH 5.0, $28^{\circ}C$, 1 vvm for aeration and 300 rpm for agitation. In order to minimize the inhibition effect of glucose on the initial growth of mycelia and to maximize the production of extracellular $\beta$-glucan, we have reduced the initial glucose feed to 4% and added 2nd feed at the point of 70 hr from the initial feed. The 2nd feed was composed of glucose 3%, yeast extract 0.1 % and malt extract 0.1 %. It improved the $\beta$-glucan yield upto 5.2 g/L in comparison with 2.8 g/L resulted from batch cultivation. Moreover, the serial treatment of a cell wall lytic enzyme and bromelain to the mycelia was effective for extraction of the cell wall bound $\beta$-glucan. The yield of $\beta$-glucan extraction by the enzyme treatment was 3.5 g/L, which was almost 4 times higher than that by hot-water extraction.