• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.63-65
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• 1999

Conidiobolus obscurus and C. thromboides (Zygomycetes: Entomophthorales), aphid-attacking fungi, were found on the Dactynotus species (Homoptera: Aphididae) in June 1998 for the first time in Korea. They produce globose primary conidia typical to the genus Conidiobolus but their dimensions are clearly distinguished. Conidiobolus thromboides produces rhizoids and conidiophores with cylindrical constriction at their apices but C. obscurus does not form rhizoids or constricted conidiophores. Resting spores were not found in our specimens of both species, but their vegetative structures observed readily allowed identification.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.889-893
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• 2012

Appressorium is a specialized infection structure of filamentous pathogenic fungi and plays an important role in establishing a pathogenic relationship with the host. The Egh16/Egh16H family members are involved in appressorium formation and pathogenesis in pathogenic filamentous fungi. In this study, a homolog of Egh16H, Magas1, was identified from an entomopathogenic fungus, Metarhizium acridum. The Magas1 protein shared a number of conserved motifs with other Egh16/Egh16H family members and specifically expressed during the appressorium development period. Magas1-EGFP fusion expression showed that Magas1 protein was not localized inside the cell. Deletion of the Magas1 gene had no impact on vegetative growth, conidiation and appressorium formation, but resulted in a decreased mortality of host insect when topically inoculated. However, the mortality was not significant between the Magas1 deletion mutant and wild-type treatment when the cuticle was bypassed by injecting conidia directly into the hemocoel. Our results suggested that Magas1 may influence virulence by affecting the penetration of the insects' cuticle.

• Journal of Sericultural and Entomological Science
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• v.47 no.1
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• pp.18-30
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• 2005

Morphological characteristics of Cordyceps species and its allies collected in Korea were clarified. Through the survey conducted from June 1999 to October 2002 in 19 mountains in Korea, 667 samples of entomogenous fungi were collected. Cordyceps and its allies of 17 species of 5 genera were identified as Cordyceps gracilioides, C. japonica, C. longissima, C. martialis, C. militaris, C. myrmecophila, C. nutans, C. pruinosa, C. sphecocephala, C. tricentri, Hirsutella nutans, Paecilomyces cicadae, P. farinosus, P. tenuipes, Paecilomyces sp., Shimizuomyces paradoxa, Tilachlidiopsis nigra. The fungi with insect hosts have been collected mainly in the place of shade or mosses near brooks and streams that had high humidity. Overall the frequenct of fungal infection in natural ecosystem was relatively low as few as 10 collections per each species. However, many species were found in terms of the few number of colleciton sites with seasonal limitations. Occurrence of the fungi in Jeju island remote from inland of the Korean peninsula were diverse in their species due to the varied weather of vertical distribution following the altitude. Three most common species were C. nutans, P. tenuipes and C. militaris, mainly found early in August when the relative humidity and temperature were high, of which C. nutans occupied the highest frequency consisting of 65% in total collections. Neither variation in ascomata arrangement in stromata nor developement of secondary spores was recognizable, while the number, shape and colour of stromata varied with insect hosts and weather conditions.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.440-446
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• 2004

Interest in in vitro study of entomopathogenic fungi, including Cordyceps species, has been increasing due to their valuable bioactive compounds and biocontrol effects. Among Cordyceps species, in vitro stromata of C militaris has been successfully produced and cultivated for industrial purposes. However, genetic study on in vitro stromata formation of C militaris has not been carried out yet. Here, relationship between mating system and perithecial stromata formation of C militaris is reported. Mating system was determined by observing perithecial stromata formation from mono-ascospore cultures and their pair-wise combinations. Certain combinations of mono-ascospore strains produced perithecial club-shaped stromata, whereas other combinations produced either no stromata or only abnormal non-perithecial stromata. Similarly, mono­ascospore cultures without combination produced either no stromata or only abnormal non­perithecial stromata. Despite obvious heterothallism, self-fertility was occasionally observed in few strains of C militaris. These observations indicated that C militaris behaves as a bipolar het­erothallic fungus and requires two mating compatible strains in order to produce regular club­shaped perithecial stromata, a fundamental requirement for its industrial cultivation.

• Mycobiology
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• v.40 no.2
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• pp.111-116
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• 2012

Ten strains of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were evaluated to find the most effective strain for optimization studies. The first criterion tested for strain selection was the mortality (> 50%) of Spodoptera litura larvae after inoculation of the fungus for 4 days. Results on several bioassays revealed that B. bassiana BNBCRC showed the most virulence on mortality S. litura larvae (80% mortality). B. bassiana BNBCRC also showed the highest germination rate (72.22%). However, its conidia yield ($7.2{\times}10^8$ conidia/mL) was lower than those of B. bassiana B 14841 ($8.3{\times}10^8$ conidia/mL) and M. anisopliae M6 ($8.2{\times}10^8$ conidia/mL). The highest accumulative radial growth was obtained from the strain B14841 (37.10 mm/day) while the strain BNBCRC showed moderate radial growth (24.40 mm/day). M. anisopliae M6 possessed the highest protease activity (145.00 mU/mL) while M. anisopliae M8 possessed the highest chitinase activity (20.00 mU/mL) during 96~144 hr cultivation. Amongst these criteria, selection based on virulence and germination rate lead to the selection of B. bassiana BNBCRC. B. bassiana B14841 would be selected if based on growth rate while M. anisopliae M6 and M8 possessed the highest enzyme activities.

• YAKHAK HOEJI
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• v.48 no.2
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• pp.153-158
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• 2004

Paecilomyces tenuipes is one of the famous Chinese medicinal entomopathogenic fungi that parasite in the lavae of silkworm. A cytotoxic compound, 4$\beta$-acetoxyscirpendiol (ASD) was isolated from a methanolic extracts of Paecilomyces tenuipes. The ASD compound belongs to scirpenol subfamily of trichothecene mycotoxin. In a continuation of the elucidation of the mechanism of ASD, we report here the evidences of induction of apoptosis by ASD in human Jurkat T cell line. In MTT reduction assay for monitoring cell viability, ASD showed strong toxicity. The 50 percent inhibitory concentrations of ASD against human T lymphoid Jurkat cell was 59.5 ng/$m\ell$. Phosphatidylserine externalization was increased by ASD at 3 and 6 hrs when compared with that of 6 hrs in the cell line showing in a time-dependent manner. When whole lysates of cells treated with ASD were subjected to western blot assay, 113 kDa poly(ADP-ribose) polymerase (PARP) was significantly cleaved to 89 kDa fragment. Time-dependent DNA fragmentation was also observed when Jurkat T cells were treated with ASD at 100 ng/$m\ell$ for 6 hrs and 18 hrs at the ratios of 8.5% and 15.0%, respectively. From these data, Jurkat T lymphocytes treated with ASD from Paecilomyces tenuipes underwent typical cascades of apoptotic cell death.

• Korean Journal of Clinical Laboratory Science
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• v.44 no.4
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• pp.216-221
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• 2012

The fruiting body of Cordyceps is derived from the pupa or larva of insects infected by the entomopathogenic fungi Cordyceps. The fruiting body has been used as an anti-cancer and anti-inflammatory ingredient in traditional Chinese medicine. The biochemical characteristics of protease isolated from Cordyceps nutans were investigated in this study. The culturing period for production of protease by C. nutans was 10days. The acidity was pH 7.0, and the temperature was $25^{\circ}C$. The carbon and nitrogen sources for the production of the protease were glucose and yeast extract, respectively. The ratio of C/N was 2% glucose and 0.6% yeast extract. 0.06% $CuSO_4$ was used as the inorganic salt. The investigation into the acidity of the protease produced by C. nutans revealed that the optimal pH and temperature were pH 7.0 and $30^{\circ}C$. The stability of the protease was shown as pH 6.0~9.0 and $30{\sim}50^{\circ}C$. The investigation into the influence of the metal ions on the enzyme activation of C. nutans revealed that it was inhibited in $ZnSO_4$ and activated in $FeSO_4$.

• Mycobiology
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• v.46 no.4
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• pp.440-447
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• 2018

Dual biocontrol of both insects and plant pathogens has been reported for certain fungal entomopathogens, including Beauveria bassiana and Lecanicillum spp. In this study, we demonstrate, for the first time, the dual biocontrol potential of two fungal isolates identified by morphological and phylogenetic analyses as Isaria javanica. Both these isolates caused mortality in the greater wax moth, and hence can be considered entomopathogens. Spores of the isolates were also pathogenic to nymphs of the green peach aphid (Myzus persicae), with an $LC_{50}$ value of $10^7spores/mL$ 4 days after inoculation and an $LT_{50}$ of 4.2 days with a dose of $10^8spores/mL$. In vitro antifungal assays also demonstrated a strong inhibitory effect on the growth of two fungi that are pathogenic to peppers, Colletotrichum gloeosporioides and Phytophthora capsici. These results indicate that I. javanica isolates could be used as novel biocontrol agents for the simultaneous control of aphids and fungal diseases, such as anthracnose and Phytophthora blight, in an integrated pest management framework for red pepper.

• Korean journal of applied entomology
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• v.40 no.1
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• pp.51-58
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• 2001

Entomopathogenic fungus, Paecilomyces japonicus, has been commercially used as medicinal purpose . The silkworm, Bombyx mori, as an optimal host for the fungi, has been selected and used for the production of the fungal fruit bodies. In current method, newly molted fifth instal larvae should be exposed to the adverse stress environment of high temperature (3$0^{\circ}C$), high relative humidity ( 90%), and starvation for 24h for better fungal inoculation to the host insects. In this study, an alternative method using chemical agent, dexamethasone (DEX: an eicosanoid biosynthesis inhibitor), was tried to get the immunodepressive effect on the larvae to elevate the inoculation rate of the fungi to the silkworm without any harsh rearing environment. DEX (100$\mu\textrm{g}$) showed significantly synergistic effect on the hemocyte lethality of the fungus, and was effective to decrease cellular immune responses measured by the number of hemocyte microaggregation and phenoloxidase activity of the fifth instar larvae in response to the fungal injection. A detergent of 0.05% Triton-X was effective to increase the in- oculation rate of the fungi to the larvae and used in all fungal spraying solutions. Without any environ- mental stress treatment, only DEX (100$\mu\textrm{g}$) injection to the fifth instar larvae followed by the fungal spray was effective to get the inoculation rate equivalent to the current fungal spray method requiring harsh rearing environment. These results suggest that the inoculation of P. japonicus can be elevated by the help of DEX and that the silkworms use eicosanoids to elicit cellular immune response against fungal pathogen.

• The Korean Journal of Soil Zoology
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• v.9 no.1_2
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• pp.1-5
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• 2004

Insect pests and their natural enemies of Hibiscus Linne (Malvaceae) were investigated from March 2002 to November 2004. Fourteen insect pest species of 9 families in 5 orders were collected from Hibiscus syriacus: 5 species in Homoptera, 3 species in Lepidoptera, 2 species in Coleoptera, 1 species in Orthoprera, 1species in Hemiptera, 1 spedies in Acarina, and 1 species in Stylommatophora. Especially, Aphis gossypii Glover (Aphididae), Anomis megogona Walker(Noctuidae) and Tetranychus urticae Koch (Tetranychidae) were very important species because of their increasing daminge. The highest donsities were observed from May to June in August in Tetranychus urticae. As the enemies and ento-mopathogens of insect pests on Hibiscus syriacus, 1 species of bacteria, 3 species of fungi, 1 species of fungi, 1 species of Hemiptera, 1 species of Coleoptera, 2 species of Hymenopetera, 2 species of Diptera, and 1 species of Acarina were investigated. As the predators and parasitoids of Aphis gossypii, Aphidoletes aphidoletes aphidimyza Rondani (Cecidomyiidae), Meliscaeva cinctella Zetterstedt (Syrphidae), Harmonia axyridis Pallas (Coccinellidae), and Aphidius gifuensis Ashmead (Braconidae), entomopathogenic fungi, Vericillium lecani naturalis strain (Moniliaceae) and Beauveria bassiana naturalis strain strain (Hypocreaceae) were observed and Bacillus thuringiensis naturalis strain (Bacillaceae), B. bassiana, Metarhizium anisopliae naturalis strain (Hypocreaceae), predators of Tetranychus urticae, Amblyseius sp. (Phytoseiidae), and Orius sp. (Anthocoridae) were observed.