• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.393-406
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• 1993

Antibacterial substances produced by Lactobacillus casei subsp. and Streptococcus faecium were examined for its antibacterial effects against some pathogenic bacteria. They were partially purified with ammonium sulfate precipitation, methanol-acetone extraction, G-50 gel filtration and examined its characteristics. When L casei subsp. and Str faecium were cultivated in MRS broth, stationary phase of L casei is until 24 hours and Str faecium is 20 hours. pH change of the cultured medium was both decreased after 12 hours and then constant at pH 4.5~4.6 after 28 hours. MRS broth culture fluids of L casei subsp. and Str faecium appeared the antibacterial effects by the spot-on-the-lawn method against ETEC, Sal pullorum and Sta aureus. Culture filtrates of L casei subsp. and Str faecium also appeared the antibacterial effects by the disc diffusion method. Culture filtrates of L casei sub. rhamnosus 7469 produced 0.032M of lactic acid and 0.01M of acetic acid. Str faecium 27273 also produced 0.027M of lactic acid and 0.01M of acetic acid. Protein concentrations of culture filtrates produced by L casei sub rhamnosus 7469 and Str faecium 27273 was $495{\mu}g/m{\ell}$ and $594{\mu}g/m{\ell}$, respectively. Antibacterial substances which are partially purified by ammonum sulfate precipitation, methanol-acetone extraction and G-50 gel filtration inhibit the growth of ETEC, Sal pullorum and Sta aureus. Characteristics of purified antibacterial substances was examined. Its molecular weight was about 31Kd, stabilized at $100^{\circ}C/20min.$ and some of proteolytic enzyme treatment.

• The Korean Journal of Food & Health Convergence
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• v.9 no.6
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• pp.1-7
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• 2023

Secondary metabolites in the culture filtrates of lactic acid bacteria offer varied chiral moieties, making them a valuable resource for drug design scaffolding. Our previous methodology included using a combination of anion exchange resins, Amberlite IRA-67 and Purolite A420S, to purify significant quantities of Lactobacillus plantarum LBP-K10 peptidyl compounds. However, current experimental evidence regarding the impact of native culture extracts and/or filtrates on pathogenic fungi in vivo/in vitro is insufficient. This study analyzed the antifungal properties of two different probiotic cultures: the CH₂Cl₂-extracted filtrate of Chinese cabbage kimchi (CH₂Cl₂-extracted CCK_WLB and CH₂Cl₂-extracted CCK_WOLB) and the non-extracted filtrate of Chinese cabbage kimchi (non-extracted CCK_WLB and non-extracted CCK_WOLB). The samples were divided into two groups: one group was inoculated with probiotics while the other group remained non-inoculated. Filtrates from both experimental groups were utilized for antifungal assays. The treatments employing CCK_WLB, with an initial inoculation of Lb. plantarum LBP-K10 as a starter, demonstrated significant antifungal activity under various experimental conditions. Our study offers new perspectives on the antifungal properties of CH₂Cl₂-extracted kimchi filtrates, which are naturally produced by lactobacilli. The efficacy of antifungal compounds is supported by substantial evidence demonstrating their efficient uptake by cells and the antifungal properties exerted by metabolites.

• The Korean Journal of Mycology
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• v.18 no.4
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• pp.181-190
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• 1990

The growth and biochemical activities of Chlorella fusca were studied in the presence of different concentrations of either filtrates or mycelial mats of Saprolegnia ferax and Pythium graminicola. Low concentrations of both fungal filtrates exerted increase in total count, dry weight and in the biosynthesis of photosynthetic pigments, carbohydrates and nitrogen content. High concentrations showed inhibitory effect on both growth and biochemical activities of Chlorella fusca. Supplementation with different concentrations of dry mycelial mats of either fungi the culture of Chlorella showed elevation in biomass, dry weight, and biosynthesis of carbohydrates and nitrogen content especially at low concentrations. The contents of photosynthetic pigment were inhibited only at low concentrations. Neither the culture filtrate of Pythium nor Saprolegnia had cellulolytic activity, although polygalacturonase enzymes were detected, whereas chloroform-extract of both fungal filtrates showed blue spots under long wave light (366 nm).

• Korean journal of applied entomology
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• v.1
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• pp.42-46
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• 1962

1) The purpcse of the present study is to investigate the effects of culture filtrates of Fuarsium oxysporum f. vasinfectum which is known to produce wilt toxin (fusaric acid) on the germination of host plants (sesame, cotton) and non-host plants (wheat, rice). 2) The experiment on the germination of sesame, cotton, wheat and rice seeds in the seed beds separately added with culture filtr ates of 10 differential strains of Fusarium oxysporom f. vasinfectum demonstrated that culture filtrates of most strains of the fungus inhibit or retard the germination of seeds of 4 plants used in this study while those of a few strains do not give notable influence on the germination of seeds of those plants. a) Culture filtrates of strain 201 of the fungus strongly inhibited the germination of seeds of those plants in nearly same degree, but culture filtrates of the other strains, 281, 321, etc., showed remarkable differences in the toxicity inhibiting or retarding the germination of the seeds of those plants. b) In general, sesame seeds are greatly susceptible, wheat and cotton seeds are moderately susceptible and rice seeds are resistant to the toxicity of culture filtrates of the fungus. 3) In the soil containing a number of differential strains of Fusarium oxysporum f. vasinfectum, the germination of seeds and also the growth of seedlings of non-host plants are possibly checked by the toxic substance, fusaric acid produced by the fungus.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.292-297
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• 1995

We developed an in vitro assay method for evaluating plant growth promotion and providing an evidence that the growth promotion is rendered by growth enhancing factors. The amendment of culture filtrates of Trichoderma harzianum T95 and Gliocladium virens G872 and G872B in Murashige and Skoog (MS) agar medium enhanced the cotyledon growth of cucumber in terms of fresh weight and primary leaf area of cucumber cotyledon cuttings, of which the treatment of G. virens G872B was the most effective. The mycelial culture filtrate of G872B was more effective in the growth promotion than its conidial germling filtrate. The addition of 1% sucrose in MS mineral medium with 0.1% culture filtrates of the antagonists (T95 and G872B) was optimum for enhancing the effect of the filtrates on the growth of cotyledon cuttings in vitro. When cucumber seeds treated with G872B, Pseudomonas putida Pf3 or the G872B-Pf3 mixture were planted in a greenhouse, the rate of seed germination, biomass of shoot and root, and yield of cucumber fruits were increased, especially by G872B or the G872B-Pf3 mixture. Correspondingly, cucumber fruit yields in early to middle-cycles of harvest were significantly greater in the plots of G872B than the control and Pf3-treated plots, and the final yield was highest in the plots of the G872B-Pf3 mixture applications.

• The Korean Journal of Mycology
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• v.21 no.2
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• pp.112-119
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• 1993

Various microorganisms secreting plant growth regulators were screened from the 100 microbial isolates including bacteria, actinomycetes and fungi. The isolates showing distict influence on the plant growth were identified as Aspergillus niger. The germinations of Raphanus and Cucubis seeds were completely inhibited by the culture filtrates of A. niger KK, A. niger KKS and A. niger ATCC 9462. The culture filtrates of the three strains also inhibited the formation and development of roots and hypocotyls of Raphanus. The culture filtrates of A. niger ATCC 26550 induced the hypocotyl curvature of Raphanus like plant hormone-auxin and at the same time caused the necrosis of the whole leaves.

• Journal of Forest and Environmental Science
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• v.34 no.5
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• pp.395-404
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• 2018

Since the mass mortality of Quercus mongolica has been first reported in Gyeonggi province at 2004, the disease spread rapidly over Korean peninsula annually. Ambrosia beetle (Platypus koryoensis) was known as the insect vector of oak wilt fungus, Raffaelea quercus-mongolicae, and control methods of the disease had mainly been focused on eradication of insect vector. However, for the efficient management of the disease, combined control methods for both of the pathogenic fungus and insect vector are strongly required. As one of the efforts to suppress the pathogenic fungus, antifungal activities of Streptomyces isolated from oak forest soil were assayed in this study. Optimum culture condition for the selected isolates was also studied, As a result, Streptomyces blastmyceticus cultured in PDB (Potato Dextrose Broth) at $25^{\circ}C$ for 1 week showed the strongest antifungal activity against oak wilt fungus. Mycelial growth inhibition rates (MGIRs) of Streptomyces isolates were compared on culture media supplemented with heated and unheated culture filtrates of S. blastmyceticus. MGIRs on culture media with unheated culture filtrates were generally higher than those on culture media with heated culture filtrates. Antagonistic mechanism to get involved in the inhibition of hyphal growth and spore formation of the pathogen is due to the antifungal metabolites produced by Streptomyces. This study will provide the fundamental information in developing biocontrol agents for the environment-friendly management of oak wilt disease.

• The Journal of the Korean Society for Microbiology
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• v.20 no.1
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• pp.45-53
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• 1985

This study was undertaken to assess the susceptibility of pigmented and nonpigmented strains of Serratia marcescens to antibiotics and human sera, and the effect of culture filtrates from pigmented and nonpigmented of Serratia marcescens on humoral and cellular immune responses in mice to thymus-dependent and indepependent antigens. Humoral immune response was measured by hemagglutinin (HA) and hemolysin (HE) to sheep red blood cell (SRBC), and Arthus or antibody response to polyvinylpyrrolidone (PVP). The cellular immune response was measured by delayed-type hypersensitivity (DTH) determined by footpad swelling reactin to SRBC. The resistance of pigmented strains of Serratia marcescens to the bactericidal action of heat inactivated human serum was insignificantly greater than that of nonpigmented strains. However, the pigmented strains were significantly more resistant to the bactericidal action of heat-untreated human serum than that of nonpigmented strains. The clinical isolates of Serratia marcestens was also tested for their resistance to several antibiotics. There was no difference between the pigmented and non-pigmented strains in the resistance to carbenicillin. However, nonpigmented strains were more resistant to gentamicin, kanamycin and tobramycin than the pigmented strains. The intraperitoneal administration of culture filtrates from the pigmented or nonpigmented strains into mice caused enhancemented of antibody response to SRBC or PVP, and of DTH to SRBC. Besides, their enhancement of immune responses was more prominent when culture filtrate from the pigmented strains was administered.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.24-30
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• 2008

Colletotrichum gloeosporioides forms an appressorium, a specialized infection structure, to infect its hosts. Among 400 and 600 culture filtrates from fungi and class Actinomycetes, six methanol extracts (A5005, A5314, A5387, A5560, A5597, and A5598) from the class Actinomycetes significantly inhibited appressorium formation in C. gloeosporioides infecting pepper fruits in a dose-dependent manner, while conidial germination was slightly enhanced. Two (A5005 and A5560) of them also exhibited distinctive inhibitory effect on the disease progress of pepper anthracnose. Water fractions of both culture filtrates also specifically inhibited appressorium formation in C. gloeosporioides and pepper anthracnose disease. Inhibition of appressorium formation by culture filtrate of A5005 was partially restored by the exogenous calcium. This results suggests that chemicals within A5005 extents its biological activity through disturbance of intracellular $Ca^{2+}$ regulation during prepenetration morphogenesis by C. gloeosporioides. Together, cell-based and target-oriented screening system used in this study should be applicable for other plant pathogenic fungi prerequisite appressorium formation to infect their hosts.

• International Journal of Industrial Entomology and Biomaterials
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• v.35 no.1
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• pp.58-62
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• 2017

The two-spotted spider mite (Tetranychus urticae) has sustained damage on more than 200 host plants worldwide. Many farmers have relied on chemical acaricides to control mite, but the abuse of acaricides has caused serious resistance to mite. To overcome this problem, microbial control using entomopathogenic fungi have been studied. Entomopathogenic fungi have been an important role against the control of pest, and most of their culture products have been demonstrated to have virulence against pest population. In this study, we evaluated and compared the virulence of culture filtrates, aerial conidia and blastospores of selected Metarhizium anisopliae 4-2 and Beauveria bassiana 2R-3-3-1, respectively, among two-spotted spider mite-pathogenic fungi. As a result, the virulence was confirmed in all treatments, and the accumulated mortality rates were between 77 and 100% within 7 days. Especially, treatment with the fungal culture filtrate alone exhibited quite high virulence, and combined treatment with aerial conidia or blastospores enhanced activity. However, the median lethal time of treatments was not significantly different. When two isolates were compared, M. anisopliae 4-2 showed higher virulence than B. bassiana 2R-3-3-1. These results suggest that the selected two fungal isolates and their culture products could be used effectively for the control of two-spotted spider mite.