• Mycobiology
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• v.40 no.3
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• pp.164-167
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• 2012

The effects of aeration through lid filters on the hyphal growth of Lentinula edodes (oak mushroom) in sawdust cultivation bags were investigated. The aeration treatment levels were traditional 27 mm hole cotton plugs, cotton balls and combinations of seven hole sizes ${\times}$ two hole positions (up and under) in the lids covering plastic bags containing 1.4 kg sawdust medium at 63% moisture that had been autoclaved for one hour and inoculated with sawdust spawn of L. edodes strain 921. Aeration treatment effects were measured based on the $CO_2$ concentration at the 15th wk, as well as the hyphal growth rate and degree of weight loss of bags every 14 days for 15 wk. In bags with traditional cotton plugs, the $CO_2$ concentration was $3.8{\pm}1.3%$, daily mean hyphal growth was $2.3{\pm}0.6mm$ and daily mean weight loss was $0.84{\pm}0.26g$. In the bags with 15 mm diameter holes, the $CO_2$ concentration was $6.0{\pm}1.6%$, daily hyphal growth was $2.8{\pm}0.2mm$ and daily weight loss was $0.86{\pm}0.4g$. The bags with 15 mm holes had a higher $CO_2$ concentration and lower water loss than bags with other hole sizes, but the hyphal growth was not significantly different from that of other bags. The weight loss of bags increased proportionally relative to the lid hole sizes. Taken together, these results indicate that traditional cotton plugs are economically efficient, but 15 mm hole lids are the most efficient at maintaining hyphal growth and controlling water loss while allowing $CO_2$ emissions.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.291-294
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• 1998

Transfer of Candida albicans grown in Sabouraud medium to the RPMI medium induces the transition from a nonpathogenic yeast form to a pathogenic hyphal form. This transition was severely inhibited in a dose-dependent manner when deer antler extract was added to the RPMI medium in a nontoxic range (up to $500{\mu}g$). In that range, deer antler extract inhibited the hyphal transition and cell growth, whereas no effect was observed on the yeast growth. When hydrophobic or hydrophilic fractions were prepared by detergent-solubilization of deer antler extract, the hydrophobic fraction showed a large degree of inhibition of the hyphal growth in Candida albicans. Neither fraction affected the growth in the yeast form. The pattern of chitin localization in the culture of the yeast form grown in RPMI in the presence of deer antler extract was confirmed by calcofluor staining and this exhibited strongly the suppression of hyphal transition.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.36-45
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• 1994

Hyphal growth, auxiliary cell development and hyphal healing process of Gigaspora margarita, Scutellospora heterogama and S. verrucosa were investigated. The germinated hyphae from spores grew on the surface and the bottom of agar media. The hyphal growth on the surface stopped 19 to 23 days and the growth on the bottom 40 to 51 days after spore germination. Auxiliary cells began to develop 7 to 9 days after the spore germination in the media. The auxiliary cells almost always developed on the tip of a hypha branched from a secondary hypha. The cytoplasmic streaming rates in the hyphae of G. margarita and S. heterogama were $2.7\;to\;3.3\;{\mu}m/s\;and\;3.8\;to\;4.3\;{\mu}m/s$, respectively. The hyphae artificially cut were healed by connecting with a hypha grown from the spore-side hypha. We may suggest that the wound healing process of hyphae should be one of the characteristics obtained from symbiotic relationship between host plants and arbuscular mycorrhizal fungi for a long period of time.

• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.422-425
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• 1998

Chitin synthase null-mutants propagate in yeast form in RPMI medium with suppression of hyphal growth. This hyphal suppression is also observed in the wild type culture grown in RPMI medium supplemented with deer antler extract. To identify the possible target of deer antler extract, the enzymatic activities of chitin synthases were examined. The enzymatic activities of three chitin synthases, CAChsl, CAChs2, and CAChs3, were found to be differentially inhibited by deer antler extract. Of them, CAChsl, was the most sensitive to the extract. These results indicate that deer antler extract causes hyphal suppression, which resembles the effects of chitin synthase deletion, probably through direct inhibition of chitin synthases.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.376-380
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• 2009

Effects of silver nanoparticles on the phytopathogenic fungal growth were investigated. Fungal phytopathogens, especially for sclerotium-forming species Rhizoctonia solani, Sclerotinia sclerotiorum and S. minor, were selected due to their important roles in survival and disease cycle. Tests for the fungal hyphal growth revealed that silver nanoparticles remarkably inhibit the hyphal growth in a dose-dependent manner. Different antimicrobial efficiency of the silver nanoparticle was observed among the fungi on their hyphal growth in the following order, R. solani > S. sclerotiorum > S. minor. Tests for the sclerotial germination growth revealed that the nanoparticles showed significant inhibition effectiveness. In particular, the sclerotial germination growth of S. sclerotiorum was most effectively inhibited at low concentrations of silver nanoparticles. A microscopic observation revealed that hyphae exposed to silver nanoparticles were severely damaged, resulting in the separation of layers of hyphal wall and collapse of hyphae. This study suggests the possibility to use silver nanoparticles as an alternative to pesticides for scleotium-forming phytopathogenic fungal controls.

• Mycobiology
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• v.31 no.4
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• pp.251-254
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• 2003

To select active bacterial strains to control plant diseases, 57 bacterial strains were isolated from the rhizosphere of the plants growing in various areas such as coast, middle and top of Halla Mountain in Jeju Island. Anti-fungal effect of isolated bactrial strains was tested in vitro by incubating in potato dextrose agar with isolates of four fungal plant pathogens Rhizoctonia solani, Fusarium oxysporum, Colletotrichum gloeosporioides and C. orbiculare, respectively. Thirty-four bacterial strains inhibited the hyphal growth of the plant pathogens, from which 17 strains inhibited one of the tested fungi, 10 strains two fungi, six strains three and a strain TRL2-3 inhibited all of the tested fungi. Some bacterial strains could inhibit weakly the hyphal growth of the plant pathogens, whereas some did very strongly with apparent inhibition zone between the plant pathogens and bacterial strains indicating the unfavorable condition for hyphal growth. Although there was no apparent inhibition zone, some bacterial strains showed a strong suppression of hyphal growth of plant pathogens. Especially, the inhibition by TRL2-3 was remarkably strong in all cases of the tested plant pathogens in this study that could be a possible candidate for biological control of various plant diseases.

• Korean Journal Plant Pathology
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• v.1 no.2
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• pp.122-127
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• 1985

Three rice cultivars, Aichi-asahi, Toyotama and Yamabiko, possessing a resistance gene $Pi-\alpha$ were evaluated for penetration, hyphal growth in the leaf epidermis and lesion formation using 6 isolates of Pyricularia oryzae by treating pre- and post disposing temperatures of $23/15^{\circ}C\;and\;29/21^{\circ}C$ (day/night) regimes, respectively. Percent penetration of the fungus was higher on the seedlings disposed at $29/21^{\circ}C$ regime and more lesions were formed at 7 days after inoculation than at $23/15^{\circ}C$ regime. Degree of hyphal growth and number of host cells with hyphal growth were remarkably increased from 72 to 96 hr after inoculation at $29/21^{\circ}C$ regime. However, lesion formation on the seedlings disposed at $23/15^{\circ}C$ regime was delayed, possibly as a result of the suppressed hyphal growth until 96 hr after inoculation.

• Korean journal of applied entomology
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• v.19 no.4 s.45
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• pp.234-238
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• 1980

The relationships between the mean degree of hyphal growth in the leaf sheath and percent penetration in the leaf epidermis within the same predisposing temperature regime were highly significant. A positive relationship was found between degree of hyphal growth in the leaf sheath and Percent Penetration in the leaf epidermis.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.27-31
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• 1988

Biosynthesis and processing of cytoplasmic mRNA from heterogenous nuclear RNA (hn-RNA) in Aspergillus phoenicis were studied by $^{3}H$-uridine labeling and synchronous culture techniques during their life cycle. Incorporations of $^{3}H$-uridine into hn-RNA and mRNA were most rapid in vesicle-phialide fromation stage and diminished in hyphal growth stage. The processing of cytoplasmic mRNA from hn-RNA was proceeded more rapidly in hyphal growth and conidiophore formation stages than in conidia and vesicle-phialide formation stages. The specific radioactivities of hn-RNA and mRNA were very high in vesicle-phialide formation stage.

• Journal of Microbiology
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• v.33 no.4
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• pp.295-301
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• 1995

An antifungal Pseudomonas stutzeri YPL-1 produced extracellular chitinase and .betha.-1, 3-glucanase that were key enzymes in the decomposition of fungal hyphal walls. These lytic extracellular enzymes markedly inhibited mycelial growth of the phytopathogenic fungus Fusarium solani. A chitinase from P. stutzeri YPL-1 inhibited fungal mycelial growth by 87%, whereas a .betha.-1, 3-glucanase from the bacterium inhibited growth by 53%. Furthermore, co-operative action of the enzymes synergistically inhibited 95% of the fungal growth. The lytic enzymes caused absnormal swelling and retreating on the fungal hyphal walls in a dual cultures. Scanning electron microscopy clearly showed hyphal degradation of F. solani in the regions interacting with P. stutzeri YPL-1. In an in vivo pot test, P. stutzeri YPL-1 proved to have biocontrol ability as a powerful agent in controlling plant disease. Planting of kidney bean (Phaseolus vulgaris L.) seedlings with the bacterial suspension in F. solani-infested soil significantly suppressed the development of fusarial root-rot. The characteristics of a crude preparation of .betha.-1, 3-glucanase produced from P. stutzeri YPL-1 were investigated. The bacterium detected after 2 hr of incubation. The enzyme had optimum temperature and pH of 40.deg.C and pH 5.5, respectively. The enzyme was stable in the pH range of 4.5 to 7.0 and at temperatures below 40.deg.C, with a half-life of 40 min at 60.deg.C.