• Applied Biological Chemistry
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• v.42 no.3
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• pp.181-187
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• 1999

For the selection of an effective antagonistic biocontrol agent, we have isolated an antagonistic bacterium which produced extracellular chitinase, from a local soil of Kyongju, Korea. The selected strain was identified as Serratia proteamaculans 3095. The chitinase produced from Serratia sp. 3095 showed antifungal activity which can attack the hypha surface of Fusarium oxysporum and F. solani. The carbon and nitrogen sources for chitinase production were 0.15% colloidal chitin and 0.1% ammonium sulfate, respectively. Glucose in the chitinase production medium might inhibit the production of chitinase by feed back repression. The antagonistic Serratia sp. 3095 also showed a powerful biocontrol activity against F. oxysporum through in vitro test and in vivo pot test.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.208-216
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• 2010

Fusarium verticillioides is an important pathogen of maize, being responsible for ear rots, stalk rots, and seedling blight worldwide. During the past decade, F. verticillioides has caused several severe epidemics of maize seedling blight in many areas of China, which lead to significant losses. In order to understand the molecular mechanisms regulating fungal development and pathogenicity in this pathogen, we isolated and characterized the gene fpk1 (GenBank Accession No. EF405959) encoding a homolog of the cAMP-dependent protein kinase catalytic subunit, which included a 1,854-bp DNA sequence from ATG to TAA, with a 1,680-bp coding region, and three introns (lengths: 66 bp, 54 bp, and 54 bp), and the predicated protein precursor had 559 aa. The mutant ${\Delta}fpk1$, which was disrupted of the fpkl gene, showed reduced vegetative growth, fewer and shorter aerial mycelia, strongly impaired conidiation, and reduced spore germination rate. After germinating, the fresh hypha was stubby and lacking of branch. When inoculated in susceptible maize varieties, the infection of the mutant ${\Delta}fpk1$ was delayed and the infection efficiency was reduced compared with that of the wild-type strain. AU this indicated that gene fpk1 participated in hyphal growth, conidiophore production, spore germination, and virulence in F. verticillioides.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.242-247
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• 2008

In the fungal pathogen Candida albicans, the yeast-to-hyphal transition occurs in response to a broad range of environmental stimuli and is considered to be a major virulence factor. To address whether the zinc homeostasis affects the growth or pathogenicity of C. albicans, we functionally characterized the zinc-finger protein Csr1 during filamentation. The deduced amino acid sequence of Csr1 showed a 49% similarity to the zinc-specific transcription factor, Zap1 of Saccharomyces cerevisiae. Sequential disruptions of CSR1 were carried out in diploid C. albicans. The csr1/csr1 mutant strain showed severe growth defects under zinc-limited growth conditions and the filamentation defect under hypha-inducing media. The colony morphology and the germ-tube formation were significantly affected by the csr1 mutation. The expression of the hyphae-specific gene HWP1 was also impaired in csr1/csr1 cells. The C. albicans homologs of ZRTl and ZRT2, which are zinc-transporter genes in S. cerevisiae, were isolated. High-copy number plasmids of these genes suppressed the filamentation defect of the csr1/csr1 mutant strain. We propose that the filamentation phenotype of C. albicans is closely associated with the zinc homeostasis in the cells and that Csr1 plays a critical role in this regulation.

• Journal of Plant Biology
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• v.34 no.1
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• pp.45-51
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• 1991

Morphological variability was quantified for Endarachne binghamiae J. Agardh from five local populations collected in December, 1989 and in March, 1990. The sampling sites were chosen at intervals of 50'N along the east coast of Korea. Fifty individuals were haphazardly collected for the relationship between the blade length and reproduction, among which twenty five individuals were randomly selected for morphological variation. The Korean plants of E. binghamiae had the capacity of reproduction at an early stage of growth. The holdfast diameter and the plurangial length showed clinal variation of increment from the north to the south whereas the cryptostomata from the south to the north. The holdfast diameter, the blade thickness, the number of plurangial blades and the cryptostomata increased from December to March, when the blade length decreased. Endarachne is distinguished by the densely interwoven hypha I cells in the medulla, [our to eighteen rows of the plurangial compartments, and absence of paraphyses between plurangia. Therefore E. binghamiae should not be combined into Petalonia, but rather the Soviet plants of P. zosterijolia may be renamed as a taxon belonging to the genus Endarachne.rachne.

• The Korean Journal of Mycology
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• v.31 no.2
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• pp.117-119
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• 2003

A stem rot of eggplant (Solanum melongena) was found in experimental field of Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted and white turf of fungal mycelium mats was spread over lesions. Sclerotia were farmed on the stems near soil line. The sclerotia of the fungus eadily were produced in artificial media such as PDA at $30^{\circ}C$. The sclerotia were globoid, $1.0{\sim}3.4mm$ in diameter and brown in color. The optimum temperature for growth of the fungus was about $30^{\circ}C$. The typical clamp connections were found in the hypha formed on PDA, and was $3.8{\sim}10.6{\mu}m$ in size. On the basis of mycological characteristics and pathogenecity test, the fungus was identified as Sclerotium rolfsii. This is the first report of stem rot of eggplant caused by Sclerotium rolfsii in Korea.

• The Korean Journal of Mycology
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• v.8 no.1
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• pp.1-5
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• 1980

This study was undertaken to investigate the activity or the water extract of Polygonum aviculare Linne in vitro. Some of the purely isolated strains or dermatophytes were inoculated on Sabouraud's dextrose agar medium containing different concentrations of the Polygonum extracts and their growth was observed for about two weeks at room temperature. Then we measured the sizes of fungal colony grown in various conditions and compared them with those of Sabouraud's medium as control to determine fungistatic effectiveness of the extract. For additional study, slide cultures on Sabouraud's dextrose medium and Sabouraud's media containing 3ml/10ml extract were performed with Epidermophyton floccosum to observe the growth of hyphae, sporulation and other mycological findings. 1. The growth of Epidermo-phyton floccosum was completely inhibited in the media containing 3ml/l0ml Polygonum extract. 2. Trichophyton rubrum, Trichophyton mentagrophytes and microsporum canis were completely inhibited in several strains of each specimen and a moderate inhibitory effect was observed in all of another strains in the media containing the 3ml/10ml extract. 3. In the slide culture of Epidormophyton floccosum the hypha was thin and more desiccated. The characteristic macroco-nidia formation was not observed on the media containing 3ml/10ml Polygonum extract as compared with those findings of Sabouraud's dextrose control medium.

• The Korean Journal of Mycology
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• v.13 no.3
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• pp.179-183
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• 1985

Cylindrocarpon spp. were isolated from the soil where strawberry was grown in Suweon by soil plate method: colonies reaching 10 mm diam. in seven days at about $20^{\circ}C$; sporodochia with cream to beige to conidial slime commonly produced; conidiophore repeatedly branched and bearing subulate phialides; macroconidia cylindrical in the center part, straight or slightly curved and mostly $1{\sim}3\;septate,\;22{\sim}45\;{\times}\;5.0{\sim}6.0\;{\mu}m$; chlamydospore abundantly produced, intercalary or terminal on mycelium, singly or in chains and smooth or warted. The hypha and spore were easily fused each other on water agar. This fungus was pathogenic strawberry as a result of inoculation test. The symptom showed dwarf and yellowing at top and rotted roots under the ground. The fungus was identified as Cylindrocarpon destructans Scholten from the shape of conidiophores and conidia, mycelial growth and pathogenicity test.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.101-106
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• 2007

Twenty-two strains of nematophagous fungi were isolated from 100 soil samples. Nematophagous fungi were classified into three categories; 3-dimensional adhesive nets (A group), 2-dimensional adhesive nets (B group) and constricting ring (C group). Nine strains were selected and identified on the basis of morphological characteristics (hypha, conidiophore, form and size of conidia, number of conidia, node of conidophore, number and location of septa, size and color of chlamydospore) and ITS (internal transcribed spacer) region of rDNA sequences. As the results, the isolated were identified as belonging to the species of Monacrosporium thaumasium (Kan-2, Kan-4, Kan-11), Arthrobotrys oligospora (Kan-9, Kan-13, Kan-20, Kan-21), A. musiformis (Kan-12), and A. dactyloides (Kan-22).

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.50-50
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• 2003

We have identified and analysed a putative response regulator two-component gene (CaSKN7) from Candida albicans and its encoding protein (CaSkn7). CaSKN7 has an open reading frame of 1677bp. CaSKN7 encodes a 559 amino acid protein (CaSkn7) with an estimated molecular mass of 61.1 kDa. CaSKN7 is a homologue of a Saccharomyces cerevisiae SKN7 that is the regulator involved in the oxidative stress response. To study the role of CaSKN7, we constructed a CAI4-derived mutant strain carrying a homozygous deletion of the CaSKN7 gene. In the caskn7 disruptant cells, the formation of germ tube require shorter time than that in the congenic wild-type strain but the growth of mycelium delayed in liquid media. In contrast, the caskn7 disruptant cells attenuate the differentiation in solid media and the virulence in mouse model system. Expression level of hypha-specific and virulence genes - HYR1, ECE1, HWP1, and ALS1 - in the caskn7 disruptant cells increased as compared with that in the congenic wild-type strain in 10％ serum YPD. Skn7 in 5. cerevisiae was found to bind the HSE element from the SSA promoter, Also, CaSkn7 contains heat shock factor DNA-binding domain and the promoters of these genes have HSE-like sties. Therefore these results show that CaSKN7 regulate the differentiation and virulence of C. albicans.

• Korean journal of applied entomology
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• v.27 no.1
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• pp.6-13
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• 1988

Studies were carried out to investigate the diapause-sensitive stage, the effect of 20-hydroxye- cdysone on diapausing pupae and the changes in pupal proteins of the fitll webworm, HYPha¬ntria cunea Drury. The stage sensitive to diapause-inducing photoperiod lies between 5th and 15th day of the larval development. And the oxygen consumption rate of diapausebound pupae decreased to a mean level of $30mu$l $O_{2}$/g/hr. The 20-hydroxyecdysone was effective in raising the respiratory acivity of 2.5% homogenate of the diapausing fall webworm pupae and in causing a normal adult development of the diapause-bound pupae. The soluble protein content rapidly declined in normally-developing pupae, but in diapause-bound pupae it was more or less static with much higher quantity. And protein bands separated from fat body of diapause¬bound pupae were different from those of nondiapausing pupae.