Identification and characterization of Metarhizium majus isolated from the edible insect Protaetia brevitarsis in Korea

Kwak Kyu‐Won,Aktaruzzaman Md.,Kim Eunsun,Kim Sun Young,Hong Seung‐Beom,Park Ji Yeong,Park Kwanho,Koo Bonwoo,Kim Yong‐Soon 한국곤충학회 2021 Entomological Research Vol.51 No.12

Edible insects are considered novel protein sources, and the edible insect breeding industry is growing rapidly. However, fungal pathogens are a major threat to this industry, and appropriate identification of causative agents is important for the development of antifungal agents. In 2019, strains of the fungal pathogen Metarhizium were isolated from infected second and third instar larvae of the economically important edible insect Protaetia brevitarsis, which were collected from separate farms in Gimhae-si, Gyeongsangnam-do, Korea. Based on morphological characteristics and multilocus phylogenetic analysis of the internal transcribed spacer region, and 50-region of gene encoding the 1-α elongation factor, the fungal strains were identified as Metarhizium majus. Here, we report the detailed phylogenetic characteristics and morphological description of this species, which is prevalent in Korea. Identification of the principal disease-causing agent can help develop disease prevention and antifungal strategies for application in edible insect-rearing farms.

동북아 피더네트워크의 Win-win전략에 관한 연구

장우준(Woo-jun jang),전찬용(Chan-Yong jeon),김태원(Tae-Won Kim),곽규석(Kyu-Seok Kwak),남기찬(Ki-Chan Nam) 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.3 No.1

최근 중국은 양산항을 개장하여 선사 유치를 위한 다양한 혜택을 제공하고, 일본은 "수퍼중추항만 육성계획“을 세워 항만의 효율성을 바탕으로 비용을 낮추려는 노력을 하고 있다. 또한 선박의 대형화에 의한 중심항만(Hub Port) 위주의 기항과 북중국의 대량 물량 발생지역에 대한 직기항 경향으로 동북아 항만간의 경쟁이 더욱더 치열해 지고 있으며 동북아 역내 피더네트워크 강화의 필요성이 제기되고 있다. 따라서, 본 연구에서는 유럽 피더네트워크 전략 사례를 바탕으로 동북아 피더시장 현황을 파악하고 동북아 피더네트워크 구조를 분석함으로써 동북아 역내 항만 및 선사간의 과당경쟁을 지양하고 서로 Win-Win할 수 있는 터미널의 전략적 활용, 선사간 제휴 확대, 항만간 협력 강화를 위한 구체적인 전략을 제시하였다. Recently, China opened Yangshan port and provides a variety of benefits for shipping companies. Japan plans to reduce logistics costs and improve efficiency through the established "super major ports" project. According to the "hub and spokes" system, the number of direct calls toward North-Chinese ports are increasing. This changing environment has negative effects on the amount of transshipment cargos in Korean ports. In order to make a hub port of a domestic port, it is necessary to develop northeast Asian feeder networks. Therefore, this paper analyzes the structure of northeast Asian feeder networks through the case study of European feeder networks strategy. Finally, we suggests the plans to reinforce feeder networks, which are strategic terminal operation, strategic alliances between shipping companies and port co-operation, for win-win strategy in the competitive northeast Asian market.

Effect of Saccharomyces cerevisiae consumption on the pathogenicity of Beauveria bassiana in Protaetia brevitarsis

Kwak, Kyu-Won,Han, Myung-Sae,Nam, Sung-Hee,Park, Kwan-Ho,Kim, Eun-Sun,Lee, Seokhyun,Song, Myung-Ha,Kim, Wontae,Choi, Ji-Young Korean Society of Sericultural Science 2016 International Journal of Industrial Entomology Vol.33 No.1

Beauveria bassiana is a common fungal pathogen of Protaetia brevitarsis larvae, and although it is less common than Metarhizium anisopliae , the pathogen still poses a great risk to humans and animals that consume infected insects, owing to B. bassiana's production of toxins like beauvericin and mycotoxin. Interestingly, the beneficial microorganism Saccharomyces cerevisiae possesses antifungal properties. In the present study, we found that S. cerevisiae inhibited the growth of B. bassiana by 97% and that S. cerevisiae failed to harm P. brevitarsis when administered via intracoelomic injection (1×10⁷ cfu/mL). In addition, we also found that S. cerevisiae consumption increased the survival time of percutaneously infected P. brevitarsis larvae by 5 d and reduced the mortality of infected larvae by 12%. Therefore, S. cerevisiae is expected to be useful in the prevention and control of B. bassiana in the production of P. brevitarsis larvae.

Prevalence of Oryctes rhinoceros nudivirus disease in Allomyrina dichotoma in Korea, 2018

Kyu-Won Kwak,Heui-Sam Lee,Myung-Sae Han,Sung-Hee Nam,Kwanho Park 한국농약과학회 2018 한국농약과학회 학술발표대회 논문집 Vol.2018 No.10

Identification and Characterization of Metarhizium anisopliae in Scolopendra subspinipes mutilans from Jeju island

Kyu-Won Kwak,Hyung Joo Yoon,Myung-Sae Han,Sung-Hee Nam,Kwan-Ho Park,Eun-Sun Kim,Seokhyun Lee,Myung-Ha Song,Wontae Kim,Ji-Young Choi 한국응용곤충학회 2016 한국응용곤충학회 학술대회논문집 Vol.2016 No.10

The purpose of this study was to identify the new fungal disease of Scopendra subspinipes mutilans (Chilopoda: Scolopendridae) from Jeju island in Korea. Scopendra subspinipes mutilans are also known the Chinese red head and average 20cm in length. It is used for traditional medicine for skin-disease and tumor and S. s. mutilans is recently raised in Jeju island to use healing properties. We isolated fungi from surface of infected S. s. mutilans and incubated in SDBA at 24℃ for 14days, and then identified the morphology of the fungi by light and electron microscopy. For the specific diagnosis of Metarhizium spp. in S. s. mutilans, 18srRNA of fungi was amplified by primers ITS4_MF and LR3_MR and sequenced by using the BLAST server at the National Center for Biotechnology Information. The result of the 18srRNA sequencing alignment was Metarhizium anisopliae (99.9%). The entomopathogenic fungi, M. anisopliae would be fatal cause of higher mortality to S. s. mutilans, and it is needed in vivo assay to confirm the pathogenic activities of M. anisopliae to S. s. mutilans.

Prevalence of Oryctes rhinoceros nudivirus disease in Allomyrina dichotoma in Korea, 2018

Kyu-Won Kwak,Heui-Sam Lee,Myung-Sae Han,Sung-Hee Nam,Kwanho Park 한국응용곤충학회 2018 한국응용곤충학회 학술대회논문집 Vol.2018 No.10

Allomyrina dichotoma (order Coleoptera, family Scarabaeidae) is used for development of pharmaceuticals, pet or educational purposes and animal feedstuffs. The disease occurrence and distribution of Oryctes rhinoceros Nudivirus were investigated in Allomyrina dichotoma in Korea using PCR and analyzed the DNA seqeunces using BLAST(Basic Local Alignment Search Tool). The virus infected larvae were collected from 10 insect rearing farms in five different regions (Gyounggi, Chungbuk, Chungnam, Jeonnam, Daejeon). Frequency of OrNV virus infection appeared differently depending on the regions or rearing facilities (open field, vinyl house, indoor breeding system and etc.). The collected samples of Allomyrina dichotoma raised on open fields showed the highest possibilities of OrNV virus infection. The OrNV average infection rate of open fields rearing systems was 50.0%.

Prevention of Oryctes rhinoceros Nudivirus in Allomyrina dichotoma using fermented sawdust combined Mulberry leaves and its effects in the outdoor application test

Kyu-Won Kwak,Kwanho Park,Myung-Sae Han,Heuisam Lee 한국응용곤충학회 2019 한국응용곤충학회 학술대회논문집 Vol.2019 No.04

The purpose of this study was to determine the safe and effective method for preventing the occurrence of Oryctes rhinoceros Nudivirus in Allomyrina dichotoma on agricultural farms. There is a high demand for the use of A. dichotoma larvae in animal feed and as pet for educational purpose. Recently, we reported that OrNV is fatal virus diagnosed in A. dichotoma larvae in local farms in Korea. Mulberry leaves contain 1-deoxynojirimycin that represented anti-inflammatory, anti-virus, and anti-tumor effects. To prevent OrNV, we have fed the sawdust combined with 1% and 5% mulberry leaves powder to OrNV infected 2nd and 3rd stage larvae of A. dichotoma, and identified the mortality rate(%) during ten weeks. As a results, the 2nd stage larvae which were fed the sawdust combined with 5% mulberry leaves treatment recorded 60% mortality rate after ten weeks compared to the 100% mortality rate in the control. And the fatality rate of 3rd stage larvae which were fed 5% mulberry leaves treatment decreased 70% compared to the control. Therefore, application sawdust combined with mulberry leaves might be effective in the prevention and control of OrNV disease in A. dichotoma. Additionally, in the ten insect breading farms application test, OrNV virus disease have not appeared in the mulberry leaf powder treatment group.

Preliminary identification of gut microbes between normal and diseased Dorcus titanus castanicolor (Coleoptera: Lucanidae)

Kyu-Won Kwak,이희삼,박관호,김은선,한명세,김낭희,김용순 한국잠사학회 2019 International Journal of Industrial Entomology Vol.39 No.2

The popularity of keeping stag beetles (Dorcus titanus castanicolor Motschulsky 1861, Coleoptera: Lucanidae) as pets has increased. Consistent with the rise in the number of insect farms using these beetles, the number of contaminated or diseased D. titanus castanicolor has also increased. This investigation was conducted to analyze the cause of D. titanus castanicolor disease. The contaminated larvae of D. titanus castanicolor showed Allomyrina nudivirus infection symptoms similar to those of Allomyrina nudivirus infection. However, the disease carried by of D. titanus castanicolor is not derived from the virus infecting Allomyrina, as determined by PCR. Our study revealed that the major gut microbes of infectious D. titanus castanicolor belonged to the phylum Proteobacteria, and specifically, Pseudomonas knackmussi (Symptom 1 - 39.62% to Symptom 2 - 41.50% to Symptom 3 - 76.76% as the disease progressed severely) and Citrobacter koseri (Symptom 1 - 1.48% to Symptom 2 - 6.04% to Symptom 3 - 6.16% as the disease progressed severely) were detected. Additionally, a high proportion of larvae from the uninfected group were found to harbor bacteria belonging to the phylum Firmicutes (72%). However, as the disease progressed severely in these beetles, the proportion of Firmicutes decreased (Symptom 1 - 72.03% to Symptom 2 - 44.7% to Symptom 3 - 26.3%). These findings imply that colonization by Firmicutes was inversely proportional to Proteobacteria colonization in the gut. This was found to be true for both the normal and disease conditions of D. titanus castanicolor. In this study, we examined the distribution of intestinal microbial communities in normal and contaminated larvae. We observed a correlation between these contaminated microbes and the overall health of the beetle, and our findings suggest that there may be a link between disease progression and the gut microbiome.

Microsporidia Identification of Characterization and DNA sequences in Bumble bees from Korea

Kyu-Won Kwak,Myung-Sae Han,Sung-Hee Nam,Ji-Young Choi,Wontae Kim,Seokhyun Lee,Kwan-Ho Park 한국응용곤충학회 2016 한국응용곤충학회 학술대회논문집 Vol.2016 No.04

The purpose of this stduy was to identify accurately and promptly the Microsporidia disease of bumble bees from Gangwon in Korea. Bumble bees are crucial pollinators of various crops and microsporidia are the critical infections of these hosts. Also, the various species of bumble bees have been used: Bombus terrestris, B. lucorum, B. occidentalis, B. ignites and B. impatiens etc. The symptoms of bumble bees infected microsporidia: their abdomens become distended, paralyzed and become sluggish and die early. We have identified the morphologies of the microsporidium by electron microscopy and found that the morphology of the microsporidium is rounded spore morph, with fairly small spores as described before in many other articles. For the specific and sensitive diagnosis of Nosema in bumble bees, we have developed the improved method of Polymerase Chain Reaction (PCR) conditions for expeditious diagnosis. Two pairs of primers were tested on N. bombi and the related microsporidia; Nosema apis and Nosema sp., both of which infect bumble bees and honey bees and further we have verified and analyzed DNA sequence data of N. bombi in bumble bees by using the BLAST server at the National Center for Biotechnology Information.

Optimal hatching conditions of Zophobas atratus (Coleoptera: Tenebrionidae) eggs under various culture conditions

Kwak Kyu-Won,Kim Sun Young,Ko Hyun-Jin,Lee Kyeong Yong,Song Jeong-Hun,Yoon Hyung Joo 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.4

Supermealworm, Zophobas atratus (Coleoptera: Tenebrionidae) is a tropical species used for human consumption and as an ingredient in animal feed. We investigated the hatching characteristics of Z. atratus eggs under varying conditions to optimize artificial rearing conditions. Overall, the average egg weight, width, and length decreased by 42.3%, 3.7%, and 10.1%, respectively, on the 6th day post-oviposition. We varied either temperature, photoperiod, illuminance, or humidity, while the other conditions remained constant. Of the four experimental temperatures—25 ◦ C, 27 ◦ C, 30 ◦ C, and 33 ◦ C–30 ◦ C was associated with the highest hatching rate (91.0%) during days 5–7. Although other experimental conditions did not have a significant effect on hatchability, we were able to elucidate the ideal conditions for improved hatchability. For photoperiod, hatchability was the highest (84%) at 12L/12D, followed by 81.0% at 15L/9D, and 70% at 9L/15D. Among the illuminance condi tions tested—600, 1800, and 3000 lx—hatchability was the highest at 1800 lx (82.3% on days 4–6). Among the relative humidity (RH) levels tested—50%, 65%, and 80%—hatchability was the highest at 65% RH (88.5% on days 5–6). Thus, the ideal conditions for maximum hatchability were 30 ◦ C, 12L/12D, 65% RH, and 1800 lx. Under these combined conditions, the hatching rate increased by 93.6%, and the hatching time was reduced by two days.