Two entomopathogenic bacteria, Xenorhadus nematophila and Photorhabdus temperata temperata, are known to suppress immune responses of target insects by inhibiting eicosanoid biosynthesis. This study analyzed these bacterial metabolites in their effects on hemocyte-spreading behavior of the beet armyworm, Spodoptera exigua. Both bacterial culture broth significantly inhibited the hemocyte-spreading behavior, at which the culture broth derived from the stationary growth phase had the most potent effect. Three identified eicosanoid synthesis inhibitors (benzylideneacetone, PY and Ac-FGV) impaired the hemocyte-spreading behavior of S. xigua, at which benzylideneacetone was the most potent. These three compounds share a common chemical structure: a pentenebenzene ring. Alternation of this common structure resulted in significant loss of their inhibitory activity to the hemocyte-spreading behavior.
Two entomopathogenic bacteria, Xenorhabdus nematophila (Xn) and Photorhabdus temperata temperata (Ptt), maintain monoxenic condition within host insect cadaver by synthesizing and releasing various antibiotics. These two bacteria were cultured in tryptic soy broth during different times, which were screened in their antibacterial activities. Both bacterial culture broth had high antibacterial activities against Escherichia coli at their stationary growth phase. The potent culture broth was used to screen target plant bacterial pathogens using both inhibition zone assay and liquid culture assay. Ralstonia sp. was most susceptible, while Xanthomonas sp. was highly resistant. Pseudomonas sp. and Bacillus sp. showed hemi-susceptible. The culture broth was further fractionated into hexane and diethylether extracts. Significant antibacterial effect was found in the diethylether extract
Two entomopathogenic bacteria, Xenorhabdus nematophila (Xn) and Photorhabdus temperata temperata (Ptt), are symbionts of nematodes, Steinernema carpocapsae and Heterorhabditis megidis, respectively. When the nematodes enter host insect hemocoel, the bacteria are released from the nematode intestine to insect hemocoel and cause immunosuppression, which results in septicemia. Culture broth of both bacteria had insecticidal effects when injected into hemocoel of Plutella xylostella larvae, but did not when orally administered. However, either mixture of Xn or Ptt with Bacillus thuringiensis (Bt) significantly enhanced the Bt pathogenicity against P. xylostella. The culture broth was fractionated with hexane and diethylacetate extracts. Diethylacetate extract had potent factor (s) to increase Bt pathogenicity. A compound, benzylideneacetone, identified from the diethylacetate fraction had oral toxicity against P. xylostella. This compound also showed high acaricidal effect on the two spotted spider mite, Tetranychus urticae
Varroa destructor is an ecto-parasite mite and worldwide pest of the honey bee Apis mellifera L. The pyrethroid tau-fluvalinate (Apistan), an acaricide that is tolerated by honey bees, has been used for varroa mite control since the mid 1980s. Even though various resistances to tau-fluvalinate in varroa mites have been reported from Europe, Israel, and USA, the nature of tau-fluvalinate resistance in varroa mites in Korea has never been investigated. To investigate and understand tau-fluvalinate resistance in varroa mites in Korea, we conducted bioassay in several apiaries located different regions in Korea. To understand the molecular mechanisms underlying the difference of tau-fluvalinate resistances in varroa mites, partial genomic DNA fragments of a voltage-sensitive sodium channel gene from varroa mites were cloned and sequenced, since tau-fluvalinate is known to act on the sodium channels directly. Two novel mutations in sodium channels of varroa mites were present in eight apiaries. Two mutations might be a geographical polymorphism of sodium channel of varroa mites in Korea.
아세틸콜린에스테라제(ace)는 신경연접에서 흥분성 신경전달물질인 아세틸 콜론을 후신경연접으로부터 분해시킴으로서 곤충체내의 신경전달을 원활하게 해주는 기능을 하는 신경전달물질 분해효소이다. 이 효소는 해충방제라는 농 업분야에 있어서 유기인계와 카바메이트계 살충제의 목표물로 잘 알려져 있 으며, 해충방제를 목적으로 사용한 살충제들의 남용으로 인한 약제 저항성 문 제로도 잘 알려져 있다. 이 효소는 의학분야에 있어서도 아주 많은 연구의 대 상이다. 이 효소와 관련된 인간의 질병은 너무나 잘 알려진 치매와 연관이 있 다. 현재까지 치매의 종류는 몇 가지로 구분되어 지지만, 특히 많이 알려져 있는 것이 알쯔하이머형 치매이다. 이 알쯔하이머형 치매에는 현재 까지 3가 지의 가설이 있으며, 활발하게 그 원인과 발병기작 연구가 전 세계적으로 진 행 중이다. 3가지의 가설 중에서 ace와 관련된 가설이 cholinergic 가설이다. 이 cholinergic 가설의 주요 내용은 저농도의 살충제에 인간이 오랜 기간 동안 노 출이 되었을 경우에 생체내에서 조금씩 감소된 ace의 량이 되돌림 현상으로 작용되어 신경연접내에 정상보다 많은 ace가 발현되고, 그로 인해서 신경전달 물질이 정상보다 빨리 분해되어 신호전달에 문제가 발생됨으로 인해서 인지 능력저하와 기억력 저하와 같은 치매현상이 나타나게 된다는 내용이다. 그래 서 본 연구는 이와 같은 가설을 증명하기위해 초파리를 이용하여 ace를 과발 현 할 수 있는 형질전환 초파리를 제작하였고, 과발현시 나타나는 이상현상을 근신경연접에서 관찰 하였다.
The Black Soldier Fly (BSF, Hermetia illucens) was widely distributed throughout Korea. This insect was mainly found in the vicinity of and in cattle sheds, manure sheds, living waste dump grounds, and food waste dump grounds. This fly is a kind of a beneficial fly because BSF adults do not go into houses, they do not regurgitate on human food, they do not bite, bother or pester humans in any way and they are not associated in any way with the transmission of disease. But their greatest attribute lies their ability to eat and digest raw waste. They can devour, for example, a large, raw, Irish potato and others in just a few hours. Unlike many other flies, since the BSF larvae have very powerful mouth parts and digestive enzymes, they can ingest raw waste far more efficiently than any other known species of fly. On this study, to investigate whether feeding strategy of the BSF larvae involves extra-oral digestion or not, and to better understand this process, the salivary glands and a few tissue from the BSF were dissected and subjected to morphological and preliminary enzyme characterization.
Since the ancient times the therapeutic application of honeybee venom (BV) is practised and persisted until the present days. Resistant bacteria are in emergence and some drugs no longer have an antimicrobial action. To purify the melittin known as antibacterial peptide, five major peptidergic subfractions were separated, purified and identified from the whole BV. We investigated the antibacterial activity of whole BV and purified melittin against Staphylococcus aureus by the minimum inhibitory concentrations (MIC) and the postantibiotic effect (PAE). The MIC of whole BV for S. aureus was 0.06 ㎍/㎖, respectively. The MIC of melittin was 0.06 ㎍/㎖ on S. aureus. The in vitro PAE of whole BV and isolated melittin were determined using E. coli and S. aureus. The PAE of whole BV against S. aureus were 3.45 h (1×MIC). The PAE of melittin against S. aureus was 4.35 h (1 × MIC). Also both whole BV and melittin killed S. aureus at 5 × MIC. The regrowth wasn't observed after 18 h. These results suggest that whole BV and melittin will be developed a novel antibacterial drug.
The current status of insect pollinator use was surveyed. Honeybee was larger than mason bee and bumblebee in average use area per farm household at kinds of insect pollinator. Insect pollinator was used at 19 crops. Among them, tomato was the most used crop, which was 44.9%, and in order to apple 26.7%, strawberry 13.1%, red-pepper 7.7% and watermelon 3.7%. In the use of insect pollinators, bumblebee, which was 56.9%, was higher than honeybee (31.3%) and mason bee (11.8%). The most farmers were a positive intention except for 1.5% of farmer in the use of insect pollinator for crop pollination. The best advantage in insect pollinator use was improvement of seed setting percentage, which was 28.3% and the worst problem was low activity at bad weather, which was 25.8%. And also, 97% of farmers have an intention to use continuously insect pollinator.
vitellogenin cDNA was cloned from the bumblebee Bombus ignitus. The cDNA encoding B. ignitus vitellogenin (BiVg) is 5473 bases long with an open reading frame of 1773 amino acid residues. BiVg possesses two consensus (RXXR/S) cleavage sites and has the conserved DGXR and GL/ICG motif near its C-terminus. The deduced amino acid sequence of BiVg cDNA showed significant similarity with hymenopteran Vgs (51% identity to Apis mellifera Vg, and 33-36% to other insect Vgs). The BiVg cDNA was expressed as a 200-kDa polypeptide in baculovirus-infected insect Sf9 cells. Northern and Western blot analyses showed the expression of BiVg in fat bodies of pupae and adults. In queens, the expression of BiVg was first detected in late pupal stage fat bodies, and secreted BiVg was also observed in late pupal stage hemolymph.
Geographic clines in genetic polymorphisms are widely believed as an evidence of climate change. We hypothesized green peach aphid, Myzus persicae Sulzer, one of the major insect pests in highland chinese cabbage cultivation, may also have some interactions with climate change. As the first step, we tried to find the available markers from six local strains (five collected at different heights in Hoengseong and Pyeongchang area and one from laboratory). A strain from Jeju island was used as an out-group. Although there was no significant difference in sequences of partial ribosomal RNA fragment and mitochondrial cytochrome oxidase I, and esterase isozyme pattern, we found four inter-simple sequence repeat (ISSR) markers in 22 used ISSR primers (+AGA, +CCA, +CGA, CGA+). These primers can be used as good markers to trace the M. persicae gene flow because they showed specific bands according to local strains.
A novel beetle antimicrobial protein from stimulated Copris tripartitus and the corresponding gene were isolated in parallel through differential display-PCR and expression in Escherichia coli. To find cDNA clones responsible for bacteria resistance, the suppression subtractive hybridization and GeneFishing differentially expressed genes system were employed in the dung beetle, Copris tripartitus immunized with lipopolysaccaride. One cDNA clone from eight subtracted clones was selected through dot blot analysis and confirmed by northern blot analysis. The 516-bp, selected cDNA clone was determined by 5' and 3'rapid amplication of cDNA ends and cloned into the GST fusion expression vector pGEX-4T-1 for expression of the protein. The expressed protein was predicted 14.7 kDa and inhibited the growth of gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa. These results implied that the expressed protein is related to immune defense mechanism against microorganism.
Sex pheromone production in lepidopteran is stimulated and regulated by a pheromone biosynthesis activating neuropeptide (PBAN). A cDNA of PBAN receptor (Plx-PBANR) isolated from female pheromone gland of the diamondback moth (DBM, Plutella xylostella (L.) encodes 338 amino acids. Plx-PBANR has conserved biochemical motifs and 7 transmembranes, indicating it belongs to G-protein coupled receptor family. Plx-PBANR expression was only found in female pheromone gland, demonstrating that pheromone gland is the only molecular target of Plx-PBAN. Human uterus carcinoma (HeLa) was stably transfected with Plx-PBANR gene and its expression was confirmed by RT-PCR analysis. Plx-PBANR expressing cells increased level of Ca2+ influx when challenged with Plx-PBAN and Hez-PBAN from Heliothis zea. When RNAi fragment for PBANR was injected into pupae, suppression of PBANR expression was confirmed by RT-PCR and maintained for at least 2 days at post-emergence. Injection of RNA fragment into pupae for inhibition of Plx-PBANR expression also inhibited mating behavior, revealing that reproductive organ of the female has no spermatocyte and that there are no successful reproductive behaviors. These results suggest of PBANR expression affects the molecular biological events of PBAN and eventually suppresses mating behavior.
Males of many cricket species produce calling songs to attract receptive, conspecific females. Calling songs which affected by calling pattern are critical for male mating success, since male with no or limited calling songs are unable to attract female crickets. Investigating among- and within-individual variation in calling pattern may reveal the presence of alternative mating tactics such as attracting females by producing calling songs or being satellites in which males intercept females who are attracted to calling males. In this study, I investigated patterns of calling song production during the entire adulthood of 32 laboratory-reared and 24 field-captured individuals of Teleogryllu emma. Using recording system which can record acoustic signals from up to 32 individuals simultaneously, I measured daily calling output (DCO) and total calling output (TCO) in addition to acoustic parameters of calling songs and classified T.emma males into consistent and inconsistent singers based on the consistency of singing. Consistent singers lived longer, sang longer both in a day and during the lifetime than the inconsistent singers. These results suggest that the consistent singers in this study may be considered to employ the calling tactic. In lab-reared individuals, there seemed to be a trade-off between increasing pulse duration and length of phrases and ling chirp although older males produced calling songs with longer ling chirps and more multiple phrases.
하나 각종 병해충의 잦은 발생으로 인해 농약살포 횟수가 매우 많다. 따라서 농작물 중 잔류농약 초과 검출건수도 전체 대상작물의 11-12%를 차지하여 가 장 높은 비중을 차지한다. 그래서 본 시험은 들깨의 주요 해충인 담배거세미 나방 유충에 대한 요방제 수준을 설정하기 위하여 남천들깨를 공시품종으로 하여 기능성작물부내 비닐하우스(40×5.4m)에서 수행하였다. 잎들깨에서 담배거세미나방 유충의 발생은 노지가 7월 중순부터 10월 중순, 시설은 7월 상순부터 11월 상순까지 발생하였고, 발생최성기는 노지 및 시설 모두 9월 중순이었다. 페로몬 트랩에 의한 수컷성충의 발생은 6월초부터 11월 상순까지 발생하였고, 발생최성기는 9월 상순부터 하순까지였다. 28℃에서 담 배거세미나방 령기별 잎들깨에 대한 1일 섭식량은 2령, 3령, 4령, 5령 및 6령 이 각각 2cm2, 5.5cm2, 15.0cm2, 31.6cm2 및 66.4cm2로 5령 이후부터 급격히 늘 어나는 경향이었다. 잎들깨에서 담배거세미나방 유충 접종밀도와 잎들깨 수량 감소율과의 회귀분석식은 담배거세미나방 2령충과 3령충이 각각 Y=2.3888X- 0.8708, Y=3.2133X-1.1625이었고, 상관계수는 각각 R2=0.988, R2=0.9886이었다. 따라서, 잎들깨의 담배거세미나방 요방제 수준(5% 수량감소율)은 2령충이 2.5 마리, 3령충은 1.9마리/100주였다.
Ooencyrtus nezarae Ishii (Hemiptera: Encyrtidae) and Gryon japonicum Ashmead (Hymenoptera: Scelionidae) are two important egg parasitoids of soybean stink bug Riptortus clavatus, one of the most serious pests in Korea. On the verge of increasing severity of R. clavatus damage in other crops, now it is important to know temporal distribution of R. clavatus and its parasitoids throughout cultivation season of various crops. Seasonal occurrence of R. clavatus and its egg parasitoids is well studied in soybean. However, occurrence of spring populations has not been fully investigated. Therefore we placed pheromone trap with refrigerated eggs in barley and early soybean fields to record occurrence of both R. clavatus and its’ egg parasitism rate in 2008. Number of R. clavatus attracted in the trap was recorded every week, and host eggs collected same time were brought into laboratory for investigation of parasitism. R. clavatus was found to exist in barley on the first day of trap installation, i.e., May 11th. Number of R. clavatus reached highest level after mid July. Only G. japonicum emerged from the eggs collected from barley field whereas O. nezarae was dominant species emerged from the host eggs collected from soybean field. We found that not only R. clavatus infestation but parasitoid occurrence begins in early spring barley field.
Benthic macroinvertebrate communities were collected in various streams in agricultural and urban areas in Korea. Community structure and species abundance distribution in benthic macroinvertebrates were comparatively analyzed to reveal ecological states pertaining to the sample sites. Species richness in the total macroinvertebrate communities decreased in the gradient along with increase in the level of pollution. Some selected taxa were present in communities collected in the streams in agricultural areas. The rank-abundance curves were also characteristic in revealing community structure according environmental impact. Patterns of species abundance were efficient in revealing ecological states of the sample sites where physico-chemical indicators may not be easily differentiated in stressful conditions. The feasibility of ecological informatics was further discussed in revealing ecological water quality.
중부지방의 배과원에서 발생하는 해충의 발생실태를 1999년부터 2008년까 지 월동해충(2월중순-하순), 생육초기(5월중순-하순), 생육중기(7월중순-하순), 생육후기(9월중순-하순)로 나누어 조사를 수행하였다. 연도별 월동해충을 조사 한 결과 꼬마배나무이, 점박이응애, 가루깍지벌레, 진딧물류 등이 월동기 주요 해충으로 조사되었다. 월동해충중 꼬마배나무이는 25cm2당 2.0-14.2마리, 점박 이응애는 25cm2당 0.5-9.0마리, 가루깍지벌레는 5주당 난괴수가 0.7-3.9개, 진딧 물류는 100눈당 알수가 0-19.4개였다. 배 생육초기에서는 꼬마배나무이, 배나 무면충, 조팝나무진딧물, 점박이응애, 가루깍지벌레가 조사되었으며, 이중에서 조팝나무진딧물이 50신초당 1.3-71.6마리가 발생하여 발생밀도가 많았다. 생육 중기에서는 꼬마배나무이, 잎말이나방류, 조팝나무진딧물, 점박이응애, 가루깍 지벌레가 발생하고 있었으며, 이중에서 점박이응애가 100엽당 3.7-300.9마리로 발생밀도가 가장 많았다. 생육후기에서는 조팝나무진딧물, 점박이응애, 가루깍 지벌레, 잎말이나방류, 꼬마배나무이, 복숭아순나방이 발생하였고, 점박이응애 가 100엽당 3.0-159.0마리로 발생밀도가 많았다. 10년간의 조사결과를 종합하 면 배에서는 조팝나무진딧물, 꼬마배나무이, 점박이응애 등이 주로 발견되었 으며, 가장 방제가 어려운 해충으로 알려진 가루깍지벌레도 해마다 지속적으 로 발생하고 있었다.
This study was performed to investigate the seasonal occurrence, developmental characteristics of each nymphal stages with different temperatures (20, 25, 30℃), longevity and fecundity of ussur brown katydid, Paratlanticus ussuriensis, damaging by outbreaks in the orchard areas of Bitan-ri, Yeongdong, Chungbuk. Paratlanticus ussuriensis occurred from late-March to late-August with peak of mid-May. Newly emerged nymphs appeared from March and do damaged fruit orchards with peak of mid-May when P. ussuriensis existed as 4th and 5th nymphal stages. P. ussuriensis adult occurred from early-June to mid-Aug. with peak of mid-July. Total density of P. ussuriensis was showed highest in mid-May. P. ussuriensis goes through nymphal stages to 7th nymph, the ovipositor began exposed to outside from the 4th instar and the body weight increased heavily from this stage and the wings were observed from 6th instar. Developmental period was longer as increased the nymphal stages. Sex ratio of collected insect was showed as 0.57; females more than males. As increased the temperature, developmental period was to be short. Preoviposition was also to be short as 5.0, 4.3, and 3.4 days at 20, 25, 30℃, respectively, and fecundity increased as 69.0, 87.1, and 104.3 at 20, 25, 30℃, respectively. Longevity of male and female at 25℃ was showed the longest with 35.7, and 32.9 days and showed the shortest with 30.1 and 28.1 days at 30℃, respectively. The difference of developmental period in male and female were showed longer in female without relation of temperature. The eggs laid were frequently distributed 3 to 4 cm from soil surface, and showed the behavior laying eggs intensively when early oviposition period.
To investigate the ecological emergence of pine sawyer beetle adult, it was examined the escape time and period and daily escape according to the tree species at Cheongwon, Chungbuk from 2006 to 2008. In the emergence chamber with non-shading treatment, the adults began to escape on May 6 in Pine and Korean white pine, May 13 in Japanese larch, and the last day of emergence was examined the beginning to Middle of June in Pine tree, middle to last of June in Korean white pine, last of May in Japanese larch, it showed the difference among tree species. In the emergence chamber with shade treatment, the first day of emergence of adult was delayed the eleven to sixteen days and showed lower 2.22℃ in temperature compare to the emergence chamber with non-shading treatment. Escape period did not show the difference between males and females. Daily emergence was escaped throughout 24 hrs. Number of emergence adult in daily hours was highest emerged with 22.8% in 12-14:00 and lowest in 06-08:00. Among escaped adults from shaded chamber in 2007, ratio of the adults of one generation per year was showed 98.8% and ratio of one generation in two year was observed 1.1 % in 2008. From 2006 to 2008, sex ratio of emerged adult from Korean white pine was showed 0.53-0.58 and its average was 0.54.
잣나무에 소나무재선충병을 매개하는 매개충인 북방수염하늘소의 잣나무 수체내 분포상황과 성충의 탈출공 크기 등을 조사하기 위하여 2007년 1월 초 순경에 경기 광주시 소재 잣나무림의 재선충병 발생지내에서 고사된 잣나무 를 벌채하여 주간부와 가지부분으로 일정한 크기(80cm)로 조제한 후 야외 망 실(4m×2m×2.5m) 내에서 2007년 4월부터 5월까지 우화시기와 매개충 탈출공의 수체내 분포양식을 조사하였다. 또한, 망실 내에서 국내에 많이 분포하여 피 해가 우려되는 소나무류(해송, 잣나무, 낙엽송, 리기다소나무)를 선별하여 투 입하고 산란선호도를 조사하였다. 북방수염하늘소 성충이 번데기방에서 우화하여 잣나무의 목질부를 가해하 고 탈출할 때 생성되는 탈출공의 직경을 조사한 결과(n=858) 최대 9.62mm, 최 소 2.02mm, 평균 5.83±0.74mm로 나타났고, 잣나무의 경급별 탈출공의 분포는 공시목 직경이 8-14cm 범위가 49.3%로 가장 많이 분포하였다. 또한, 2-4cm는 0.8%, 4-8cm는 14.3%, 14cm이상은 35.5%로 나타났다. 잣나무에 있어서 북방수 염하늘소의 분포는 주간 상부 쪽과 가지의 직경이 비슷한 크기의 수준으로 존재하기 때문에 잣나무 내 어느 위치에서도 우화탈출하여 소나무재선충을 전파 할 수 있을 가능성이 있으나 직경 8-14cm가지가 많은 중․상부쪽에 주 로 분포하는 것으로 보인다. 이는 소나무에 있어서 솔수염하늘소의 분포양식 과 비슷하다. 소나무류 수종별 산란선호도와 관련된 침입공수의 출현빈도는 해송 18.8%, 잣나무 54.0%, 리기다소나무 7.7%, 낙엽송, 20.2%로 조사되었으 며, 각각 8.2%, 31.3%, 23.8%, 56.4%의 우화탈출율을 보였다.