• International Journal of Industrial Entomology and Biomaterials
• /
• v.28 no.2
• /
• pp.71-84
• /
• 2014

The full-length heat shock protein 88 (HSP88) complementary DNA (cDNA) of Paecilomyces tenuipes Jocheon-1 was obtained by screening the Paecilomyces tenuipes (P. tenuipes) Jocheon-1 Uni-Zap cDNA library and performing 5' RACE polymerase chain reaction (PCR). The P. tenuipes Jocheon-1 HSP88 cDNA contained an open reading frame (ORF) of 2,139-basepair encoding 713 amino acid residues. The deduced amino acid sequence of the P. tenuipe s Jocheon-1 HSP88 cDNA showed 77% identity to Nectria haematococca HSP88 and 45-76% identity to other fungal homologous HSP88s. Phylogenetic analysis and BLAST program analysis confirmed that the deduced amino acid sequences of the P. tenuipes Jocheon-1 HSP88 gene belonged to the ascomycetes group within the fungal clade. The P. tenuipes Jocheon-1 HSP88 also contained the conserved ATPase domain at the N-terminal region. The cDNA encoding P. tenuipes Jocheon-1 HSP88 was expressed as an 88 kilodalton (kDa) polypeptide in baculovirus-infected insect Sf9 cells. Under higher temperature conditions for the growth of the entomopathogenic fungus, mRNA expression of P. tenuipes Jocheon-1 HSP88 was quantified by real time PCR (qPCR). The results showed that heat shock stress induced a higher level of mRNA expression compared to normal growth conditions.

• The Korean Journal of Mycology
• /
• v.46 no.4
• /
• pp.479-490
• /
• 2018

Red pepper is seriously damaged by thrips (Thrips palmi) and anthracnose caused by Colletotrichum acutatum throughout its development. Because of biotic constraints, producers often depend on chemicals that are expensive and have adverse effects on the environment, operator, and beneficial insects. In addition, resistance is developed because of the repeated use of chemicals. In recent decades, the use of microorganisms in crop protection has become a credible alternative because it is eco-friendly. In this study, we aimed to select isolates with insecticidal and fungicidal activities against the pathogens that cause anthracnose and thrips. We treated T. palmi adults and juveniles with 13 strains of entomopathogenic fungi (isolated from the soil by using the insect-bait method), and 6 strains showed excellent insecticidal activity (70-100%) 5 days after the treatment. The selected isolates were cultured with C. acutatum to screen for the strain with excellent anti-fungal activities, among which an isolate FT333 showed more than 95% control efficacy against C. acutatum in vitro. The isolate was identified as Isaria javanica through its morphological characteristics and phylogenetic analysis of the ITS and ${\beta}-tubulin$ nucleotide sequences. The Isaria javanica FT333 isolate could be used effectively for dual bio-control of thrips and anthracnose during red pepper cultivation.

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

• International Journal of Industrial Entomology and Biomaterials
• /
• v.48 no.1
• /
• pp.42-47
• /
• 2024

The value of silkworms as functional health food materials has increased, as has the interest in its disease control for stable production, and in the economic value of entomopathogenic microorganisms. In this study, we isolated and identified disease-causing fungi from white muscardine silkworms, and confirmed whether this strain could produce white muscardine silkworms. For the analysis of the cause of white muscardine disease in the infected silkworms, the fungi and prokaryotes causing the disease were identified, isolated, and identified using metagenome analysis. Metagenomic analysis detected a large amount of the fungus Metarhizium rileyi in silkworms, and a large amount of the bacterium Enterococcus mundtii, which was presumed to be the causative agent of the disease. For accurate identification of the fungi, these were purified by culture medium, and sequencing and phylogenetic tree analyses were performed using an internal transcribed spacer. As a result, M. rileyi, Cladosporium cladosporioides, and C. tenuissimum were identified. In general, M. rileyi is known to form green conidia, but in this study, white-yellow conidia were formed, indicating that the exact causative agent of the fungal disease cannot be estimated by diagnosing the symptoms. Thus, a diagnostic method is necessary for the continuously collection of required pathogens, and identifying their morphological and genetic characteristics.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.9 no.6
• /
• pp.440-446
• /
• 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
• /
• v.40 no.2
• /
• pp.111-116
• /
• 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.

• BMB Reports
• /
• v.38 no.2
• /
• pp.211-217
• /
• 2005

Cordyceps, an entomopathogenic fungus, contains many health-promoting ingredients. Recent reports indicate that the consumption of cordyceps helps reduce blood-sugar content in diabetics. However, the mechanism underlying this reduction in circulatory sugar content is not fully understood. Methanolic extracts were prepared from the fruiting bodies of Paecilomyces tenuipes, and 4-beta acetoxyscirpendiol (4-ASD) was eventually isolated and purified. $Na^+$/Glucose transporter-1 (SGLT-1) was expressed in Xenopus oocytes, and the effect of 4-ASD on SGLT-1 was analyzed utilizing a voltage clamp and by performing 2-deoxy-D-glucose (2-DOG) uptake studies. 4-ASD was shown to significantly inhibit SGLT-1 activity compared to the non-treated control in a dose-dependent manner. In the presence of the derivatives of 4-ASD (diacetoxyscirpenol or 15-acetoxyscirpendiol), SGLT-1 activity was greatly inhibited in an 4-ASD-like manner. Of these derivatives, 15-acetoxyscirepenol inhibited SGLT-1 as well as 4-ASD, whereas diacetoxyscirpenol was slightly less effective. Taken together, these results strongly indicate that 4-ASD in P. tenuipes may lower blood sugar levels in the circulatory system. We conclude that 4-ASD and its derivatives are effective SGLT-1 inhibitors.

• The Korean Journal of Pesticide Science
• /
• v.4 no.4
• /
• pp.77-80
• /
• 2000

This study was carried out to investigate infection process, symptoms and $LD_{50}$ values of the entomopathogenic fungus cordyceps, Paecillomyces japonica, on the domestic silkworm, Bombyx mori. Susceptibility of infection in the silkworms by cordyceps, Paecillomyces japonica, was 100% in $10^{7}$ block, 96% in $10^{6}$ block, 76% in $10^{5}$ block, 44% in $10^{4}$ block, 28% in $10^{3}$ block and 8% in $10^{2}$ block. Cordyceps, Paecillomyces japonica, was highly infectious to the silkworms. A pathogenicities of cordyceps, Paecillomyces japonica, may be highly virulent because of the low resistance or high susceptibility of the silkworms. Dosage of the pathogen of $LD_{50}$ was $3.78{\times}10^{3}\;spores/mm^{3}$.

• The Korean Journal of Pesticide Science
• /
• v.13 no.3
• /
• pp.177-184
• /
• 2009

This study was carried out to investigate infection process, symptoms and main component of the domestic silkworm, Bombyx mori. larvae and pupa infected with the entomopathogenic fungus Cordyceps, Paecillomyces tenuipes. The Cordyceps, Paecillomyces tenuipes, was highly infectious to the silkworms. A pathogenicities of Cordyceps, Paecillomyces tenuipes, may be highly virulent because of the low resistance or high susceptibility of the silkworms. The silkworm larva infected with Cordyceps formed phialospores on the phialides at the imperfect stage of the genus Cordyceps, But silkworm pupa infected with Cordyceps formed ascospores in the asci at the perfection stage of the genus Cordyceps. The results of analysis of health silkworm pupa and silkworm pupa infected with Cordyceps were obtained that amino acid, fatty acid, and nucleoside were very different.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.17 no.2
• /
• pp.181-187
• /
• 2008

An entomopathogenic fungus, Paecilomyces fumosoroceus SFP-198 was isolated in Kyungbuk province, Korea and screened out for the control of Trialeurodes vaporariorum nymphs. It showed 72.5% efficacy against second instars of T. vaporariorum nymphs at 6 days after treatment in the laboratory. To select an active ingredient for the mass production and the formulation, SFP-198 culture products were compared based on their insecticidal activities against T. vaporariorum nymphs. Among them, conidia and blastospores showed much higher insecticidal activity than supernatants. Furthermore, SFP-198 conidia were more heat-resistant than blastospores, and also powder form of conidia was more stable than their suspension form. SFP-198 conidia showed high pathogenicity on not only T. vaporariorum but also Tetranychus urticae in the glasshouse. This result suggested that SFP-198 conidia can be used as a multi-targeting biological control agent against sucking agri- cultural pests, such as whiteflies and mites.