• Korean journal of applied entomology
• /
• v.61 no.1
• /
• pp.173-195
• /
• 2022

Like vertebrates, insects synthesize various eicosanoids after the committed catalytic step of phospholipase A₂ (PLA₂). However, the subsequent biosynthetic steps exhibit some deviation from those of vertebrates. Due to little composition of arachidonic acid in insect phospholipids, PLA₂ releases linoleic acid, which is another polyunsaturated fatty acid and relatively rich in insect phospholipids, to synthesize arachidonic acid via chain extension and desaturation. Resulting arachidonic acid is then oxygenated into a prostaglandin (PG), PGH₂, by a specific peroxidase called peroxynectin, but not by cyclooxygenase. PGH₂ is then isomerized to various PGs such as PGA₂, PGD₂, PGE₂, PGI₂, and a thromboxane (TXB₂). All four epoxyeicosatrienoic acids such as 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET are also synthesized from arachidonic acid by oxygenation of vertebrate types of monooxygenases. However, the other type of eicosanoids called leukotrienes are found in insect tissues but their synthetic pathway is unclear. Eicosanoids mediate various insect physiological processes such as metabolism, excretion, immunity, and reproduction. Thus, identification of novel compounds interrupting eicosanoid biosynthesis would be a novel approach to develop insecticides. This review focuses on PGs and their immune mediation.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.12
• /
• pp.1644-1653
• /
• 2014

Wuyiencin is produced by Streptomyces ahygroscopicus var. wuyiensis CK-15 and is widely used as an antifungal agent in agriculture. Analysis of wuyiencin biosynthetic gene clusters reveals wysR, a member of the LAL-family of transcriptional regulatory genes. WysR consists of an N-terminal PAS domain and a LuxR family C-terminal helix-turn-helix motif. However, the roles of wysR in wuyiencin biosynthesis are largely unknown. In this study, we showed that inactivation of wysR resulted in the complete loss of wuyiencin production, which could be restored by complementation with a single copy of wysR. Furthermore, we successfully increased wuyiencin production to a significantly higher level by overexpression of wysR in S. wuyiensis CK-15. Quantitative real-time RT-PCR analysis showed that WysR regulates wuyiencin biosynthesis by modulating other putative regulatory genes. Thus, WysR was identified as an activator of wuyiencin biosynthesis, and overexpression of wysR gene proved to be an effective strategy for improving wuyiencin production.

• The Korean Journal of Mycology
• /
• v.38 no.2
• /
• pp.99-104
• /
• 2010

Dead insects infected with fungi were collected from mountains and islands in several locations in Korea from 2003 to 2007. Morphological characteristics of the fungal fruiting bodies produced on the insect samples were examined. A total of 542 entomopathogenic fungal isolates were obtained from the insect samples and identified based on their morphological and cultural characteristics. Three species of Beauveria, eight species of Cordyceps and four species of Isaria were mainly isolated from the insect samples. The other entomopathogenic fungi isolated from the insect samples were Metarhizium anisopliae, Nomuraea rileyi, Paecilomyces sp. and Verticillium sp.

• Mycobiology
• /
• v.45 no.3
• /
• pp.160-171
• /
• 2017

Larvae of Bradysia agrestis, an insect vector that transports plant pathogens, were sampled from geographically isolated regions in Korea to identify their cutaneous fungal and bacterial flora. Sampled areas were chosen within the distribution range of B. agrestis; each site was more than 91 km apart to ensure geographical segregation. We isolated 76 microbial (fungi and bacteria) strains (site 1, 29; site 2, 29; site 3, 18 strains) that were identified on the basis of morphological differences. Species identification was molecularly confirmed by determination of universal fungal internal transcribed spacer and bacterial 16S rRNA gene sequences in comparison to sequences in the EzTaxon database and the NCBI GenBank database, and their phylogenetic relationships were determined. The fungal isolates belonged to 2 phyla, 5 classes, and 7 genera; bacterial species belonged to 23 genera and 32 species. Microbial diversity differed significantly among the geographical groups with respect to Margalef's richness (3.9, 3.6, and 4.5), Menhinick's index (2.65, 2.46, and 3.30), Simpson's index (0.06, 0.12, and 0.01), and Shannon's index (2.50, 2.17, and 2.58). Although the microbial genera distribution or diversity values clearly varied among geographical groups, common genera were identified in all groups, including the fungal genus Cladosporium, and the bacterial genera Bacillus and Rhodococcus. According to classic principles of co-evolutionary relationship, these genera might have a closer association with their host insect vector B. agrestis than other genera identified. Some cutaneous bacterial genera (e.g., Pseudomonas) displaying weak interdependency with insect vectors may be hazardous to agricultural environments via mechanical transmission via B. agrestis. This study provides comprehensive information regarding the cutaneous microflora of B. agrestis, which can help in the control of such pests for crop management.

• Korean Journal of Pharmacognosy
• /
• v.14 no.3
• /
• pp.83-91
• /
• 1983

The purpose of this study is concerned with identification of floral type of commercially available honeys and pollen loads. Ikuse's technique was applied to identify the pollen species of honey and pollen loads. Among six kinds of commercially available honeys in Taegu, Korea i.e. Robinia Honey, Brassica Honey, Castanea Honey, Rhododendron Honey, Lespedeza Honey and Multipant Honey, all honeys contained pollens, which were coincident with their trade names given by the apirists, except Lespedeza Honey. The trade name of imported honeys were not given by the plant, from which pollen material and nectar were collected. Among four kinds of these products, pollen was not identified in Clover Honey. A spectrum of honey products added by pollen loads was, of course, wider than simple honey products. The pollen load showed spectrum of pollens including not only those which are specialized for wind pollination, eq. Pinus species and Gramineae, but also contained for insect pollination, eq. rose and leguminous plants.

• Animal Systematics, Evolution and Diversity
• /
• v.36 no.1
• /
• pp.60-77
• /
• 2020

Cecidomyiidae (Diptera) consists of six subfamilies, which are divided into three groups according to larval ecological habits (phytophagous, mycophagous, and zoophagous). The five basal subfamilies of Cecidomyiidae consist entirely of mycophagous species, with approximately 1500 species described worldwide and 29 previously known to occur in Korea. In this study, 37 named species (1 Lestremiinae, 29 Micromyinae, 4 Winnertziinae, and 3 Porricondylinae species) are newly reported from South Korea. We excluded Lestremia yasukunii Shinji from the list of Korean mycophagous cecidomyiids as it is a nomen nudum. Therefore, we herein officially recognize 65 species, 30 genera, and four subfamilies for the Korean mycophagous cecidomyiid fauna. We also provide diagnoses and photographs to aid species identification and discussion on the four years of gall midge taxonomic inventory in South Korea.

• Journal of the Korea Furniture Society
• /
• v.26 no.3
• /
• pp.274-285
• /
• 2015

Wood carving has been extremely widely practiced, but survives much less well than the other main materials, being vulnerable to decay, insect damage, and fire. It therefore forms an important hidden element in the art history of many cultures. Even though wood is less durable than either steel or stone, it has been used for a long time due to its usefulness. Wood has a lot of benefits. So people have used wood for materials in houses, trains, cars, bridges, and simple utilities in their ways according to their own religions, climates, and environment they are living in. Nowadays, there are wood products that are made up for its weaknesses and this has made wood be used in variety fields. Moreover, wood has been widely selected materials for sculptures, interior, and also for architecture thanks to its colors and textures. Wood has helped our life more abundant and beautiful.

• Korean journal of applied entomology
• /
• v.34 no.1
• /
• pp.9-14
• /
• 1995

From a chemist's perspective, Scarabaeidae is one of the most exciting group of insects to work on the isolation, identification, and synthesis of sex pheromones because-as opposed to Lepidoptera, which by and large utilizes straight chain alcohols, aldehydes, and acetates-the pheromonal chemistry of scarab beetles is remarkably diverse. While species in the subfamily Rutelinae utilize pheromone constituents, which are presumably fatty acid derivatives, the more primitive species in the subfamily Melolonthinae use phenolic, amino acid derivative, and terpenoid compounds. Here, I discuss the recent advances we have accomplished in the identification of scarab sex pheromones with especial emphasis on their chemical diversity. Also, I discuss the potential role of these sex pheromones in insect pest management. Field tests revealed that, in contrast to what has been frequently observed in the Lepidoptera, the higher the dosage of sex pheromone loaded in the traps the greater the capture of scarab beetles. These data suggest that mass trapping is more likely to be useful for scarab pest management than mating distruption.

• Korean journal of applied entomology
• /
• v.56 no.2
• /
• pp.223-227
• /
• 2017

The larger black flour beetle, Cynaeus angustus (LeConte) (Diaperinae: Tenebrionidae) is reported for the first time in Korea. C. angustus is economically important as an insect pest in stored products in the Nearctic region, and has been identified in several rice mills in Korea. Taxonomic diagnosis and photographs presenting the morphology of adults and larvae are provided, along with a pictorial identification key to 17 tenebrionid pests detected during quarantine in stored products in Korea.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.1
• /
• pp.1-10
• /
• 2013

The exposure of food to ionizing radiation has been recognized as a safe and effective mode of food preservation in more than 55 countries. The benefits include eradication of insect pests, inactivation of food pathogens, extension of shelf-life, and improvement in food hygiene. Regulatory authorities around the world have emphasized the implementation of various national and international regulations to facilitate trade and development of consumers' confidence in purchasing irradiated foods. Therefore, the need for reliable irradiation detection methods has increased to enforce these regulations. At present, a number of promising analytical approaches have been developed and evaluated. Moreover, about 10 European Standards have been adopted as General CODEX Alimentarius methods for the detection of irradiated foodstuffs. However, most of these methods demand relatively expensive equipment and prolonged sample preparation. Therefore, simple and cost-effective approaches would be advantageous for rapid screening of foodstuffs. The suspected samples need to be analyzed further with more validated techniques to confirm the screening results. In this review, existing screening methods (i.e. physical, chemical, and biological) for the identification of irradiated foods have been outlined along with their principles, scopes and limitations.