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        검색결과 796

        561.
        2011.10 구독 인증기관·개인회원 무료
        Although somatic cell nuclear transfer (SCNT) has successfully been produced cloned animals in several species, the cloning efficiency is extremely low. It is generally believed that the low cloning efficiency is mainly attributed to faulty epigenetic modifications underlying the aberrant reprogramming of donor cell nuclei in recipient cytoplasm after SCNT. The nuclear reprogramming process involves epigenetic modifications, such as DNA demethylation and histone acetylation, which may be a key factor in improving the cloning efficiency. Recently, the histone deacetylase inhibitors (HDACi), such as trichosatin A (TSA) and m-carboxycinnamic acid bishydroxamide (CBHA), to increase histone acetylation have been used to improve the developmental competence of SCNT embryos. Therefore, we compared the effects of TSA with CBHA on the in vitro developmental competence and pluripotency-related gene expressions (Nanog, Oct3/4 and Sox2) in porcine cloned blastocysts. The porcine cloned embryos were treated with a 50 nM concentration of TSA or a 100 μm concentration of CBHA during the in vitro early culture (10h) after cell fusion and then were assessed to cleavage rate, development to the blastocyst stage and pluripotency-related gene expressions in NT blastocysts. All data was analyzed by chi-square. Following 4-5 replicates (245, 200 and 222 for NT, TSA and CBHA treated NT embryos respectively) there was no difference between normal NT and CBHA treated NT embryos, whereas TSA treated NT embryos was significantly decreased for cleavage rate (p<0.05). The developmental competence to the blastocyst stage in CBHA treated NT embryos (18.9%) significantly increased than that of normal NT and TSA treated NT embryos (9.4% and 11.5%) (p<0.05). In addition, all of pluripotent transcription factors (Nanog, Oct3/4 and Sox2) were highly expressed in the CBHA treated NT embryos, however, Sox2 and Oct3/4 were expressed in TSA treated NT embryos and Sox2 was only expressed in normal NT embryos (p<0.05). In conclusion, the treatment of CBHA as a histone deacetylase inhibitor significantly increased the developmental competence of porcine NT embryos and pluripotency- related gene expressions (Nanog, Oct3/4 and Sox2) in NT blastocysts.
        562.
        2011.10 구독 인증기관·개인회원 무료
        The green peach aphid (Myzus persicae) is a cosmopolitan pest of agricultural and horticultural crops and causes serious economic damages. M. persica has rapidly developed resistance to a wide variety of insecticides, including pyrethroids. Target site insensitivity mechanism mediated by two mutations (L1014F and M918T) on the para-type voltage-sensitive sodium channel (vssc) is mainly responsible for pyrethroid resistance. To predict the vssc resistance allele frequency, quantitative sequencing (QS) protocol was established. Frequency prediction equations generated from the plots of signal ratios and amplification critical time showed a high correlation coefficient (r2>0.993), indicating its high accuracy in prediction. QS results revealed that the kdr-type L1014F mutation is only present in Pyeongchang strain. No field strains of M. persicae possessed the super-kdr type M918T mutation. However, a novel M918L mutation was found by genotyping approach. The allele frequencies of M918L and L1014F were 0% to 53% in populations examined, and the level of M918L mutation frequency was closely related with pyrethroid resistance. Therefore, QS-based detection of M918L mutation frequency should faciltate the monitoring of pyrethroid resistance in the field.
        563.
        2011.10 구독 인증기관·개인회원 무료
        The green peach aphid (Myzus persicae) is a serious pest of agricultural and horticultural crops all over the world. M. persica has rapidly developed resistance to a wide variety of insecticides, including carbamates. The E4/FE4 carboxylesterase is known to be involved in carbamate resistance. To compare the E4/FE4 carboxylesterase gene copy number, as a genetic resistance marker, between seven field strains, quantitative real-time PCR (qPCR) was performed. In addition, quantitative sequencing (QS) was employed to predict the frequencies of acetylcholinesterase (AChE) mutations (A301S and S431F) that are associated with target site insensitivity. All M. persica strains examined possessed the S431F mutation in the heterozygous state except for a susceptible strain, implying the possibility of AChE duplication. In contrast, no A301S mutation was found. Frequency prediction equation was generated from the plots of signal ratios and amplification critical time, which showed a high correlation (r2>0.996). QS analysis of M. persicae populations revealed that the allele frequency of S431F ranged 4% to 63%. Taken together, the AChE resistance allele frequencies determined by QS and the E4/FE4 gene copy number by qPCR should facilitate the detection and monitoring of carbamate resistance in M. persicae in the field.
        564.
        2011.10 구독 인증기관·개인회원 무료
        The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in the cultivation of various vegetables. A highly imidacloprid-resistant field population (CA-L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. IEF and 2DE analyses revealed that general esterase isozyme (pI. 5) in CA-L were dramatically overexpressed and more isozyme spots identified in CA-L compared to susceptible (CA-S) strain. To identify differentially expressed genes in CA-L, comparative transcriptome analyses based on GS-FLX were conducted with total RNA extracted from CA-L, which generated ca. 143 Mb reads. Previously reported, comparative transcriptome analyses performed in imidacloprid resistant (CA-IR) and CA-S. The comparative transcriptome analyses re-investigated after all data sets were combined together. As previously reported, seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in CA-IR and L. These results suggested that ABCC subfamily associated with imidacloprid resistance in A. gossypii.
        565.
        2011.10 구독 인증기관·개인회원 무료
        The human body and head louse are ectoparasites of humans for thousands of years. Although both body and head lice belong to a single species, Pediculus humanus, only body lice are known to transmit several bacterial diseases. This different vector competence is assumed to be due to their different immune responses. Here, the immune reactions in the alimentary canal were investigated in both two louse subspecies following oral challenge of Escherichia coli as a model gram-negative bacteria. In propagation assay, head lice suppressed the proliferation of E. coli in their epithelial cells effectively at the early stage of infection, resulting in gradual reduction of E. coli number in gut tissues. In contrast, the number of E. coli steadily increased in gut tissues of body lice. No apparent alteration of transcription was observed following E. coli challenge in three important genes for the humoral immune responses, PGRP as a recognition gene and defensin1 and 2 as effector genes. Nevertheless, the basal transcription levels of these genes were higher in the gut tissues of head lice than body lice. Considering that there is no cellular immune reactions in gut tissues, these findings suggest that the higher constitutive transcription levels of major immune genes in head lice can contribute to their initial defense and immune capacity against intestinal bacterial infection.
        566.
        2011.10 구독 인증기관·개인회원 무료
        This study was conducted to examine the community structure of ground beetles between coniferous and deciduous forest in rural landscapes along latitudinal gradient, such as Miryang-si, Yeongdong-gun, Icheon-si, and Cheolwon-gun from April to October in 2009. A total of 19 species belonging to 15 genera of 9 subfamilies were identified from 6,253 collected ground beetles. Between forest stands, 14 species belonging to 10 genera of 7 subfamilies were identified from 2,874 ground beetles in coniferous forests and 14 species belonging to 11 genera of 7 subfamilies were identified from 3,379 ground beetles in deciduous forests. Dominant species from 4 regions were Synuchus nitidus (59.4% of total) and Synuchus cyloderus (28.5%) respectively. Analysis of similarity (ANOSIM) showed no difference between forest stands, but it was significantly different among regions. Non-metric multidimensional scaling showed that 8 study sites were divergence to 2 major groups between Miryang-si and the others. Overall, community structure of ground beetles showed no difference between forest stands. In conclusion, rural forests is being discussed about important role in biodiversity conservation such as refuge from human activity, and thus, studies on the community structure of ground beetles in the rural forests will be important to manage the biodiversity in agricultural landscapes, because ground beetles are well known for general predator groups in the ecosystems.
        567.
        2011.10 구독 인증기관·개인회원 무료
        Larval stages of Callipogon relictus (Semenov) (Coleoptera: Cerambycidae), a gigantic longhorn beetle designated as a natural monument of Korea, has never been studied as it is hardly discovered in nature. The DNA barcoding gene, mt-COI, was used to identify a dead larva found in the Gwangneung forest of the Korea National Arboretum. Based on the result, we provide the morphology of the immature stage, with the illustrations of diagnostic characteristics.
        568.
        2011.10 구독 인증기관·개인회원 무료
        Rhynchium brunneum is a widely distributed wasp species in South Eastern Asia. R. brunneum females were collected from rural provinces of Cambodia, and their total RNA and venom were extracted on site. To search for novel substances in venom, a subtracted cDNA library specific to the venom gland and sac was constructed. A total of 1118 expressed sequenced sequence tags (ESTs) were sequenced and assembled into 349 contigs (107 multiple sequences and 242 singletons). In this result, we found the putative neurotoxin (DTX protein precursor), antimicrobial peptides (teratocyte-specific caboxylesterase) together with typical major components of wasp venom (venom hyaluronidase, arginine kinase, phospholipase A2, serine/theonine protein phosphatase). Additional in-depth annotation would be required for further characterization of many unidentified genes found in the EST library.
        569.
        2011.10 구독 인증기관·개인회원 무료
        After pea aphid Acyrthosiphon pisum genome project, hologenome concept was applied to pea aphid and symbioant such as Buchnera aphidicola. Here we screened symbiotic microorganism in four lab strains (two genetically different insecticide susceptible strains, host plant: cucumber and two different host adopted imiacloprid resistance strains, host plants: cucumber and potato) and four field populations (Jeju, Goryeong, Gimjae and Muju, host plant: potato) of cotton aphid based on GS-FLX pyrosequencing which were conducted with universal primer amplified partial fragments of 16S rRNA from total DNA which was extracted from each strain and population. B. aphidicola occupied over 90% of all identified prokaryotic microorganisms which all tested samples. It’s interesting that the ratio of B. aphidicola occupied over 99% in all of the tested lab strains. However, specific enterobacteriaceae occupied six to seven percents of all field populations which closely related endosymbiont of Glycaspis brimblecombei. That means B. aphidicola occupied only 91~92% of all identified prokaryotic microorganisms. Futhermore, other actinobacteridae and bacillaceae also were detected in field populations. The results obtained for these ratios suggested that there has some interaction between symbioant and environment NOT in imidacloprid resistance.
        573.
        2011.05 구독 인증기관·개인회원 무료
        Vespa tropica is a tropical species of Vespa found in Southeast Asia. V. tropica wasps were collected from rural provinces of Cambodia, and their total RNA and venom were extracted on site. To search for novel substances in venom, a subtracted cDNA library specific to the venom gland and sac was constructed and venom protein was analyzed by nano-LC-MS/MS. A total of 1127 expressed sequenced sequence tags (ESTs) were sequenced and assembled into 572 contigs (152 multiple sequences and 420 singletons). The short venom peptides were identified to be encoded from 5 contigs (43 ESTs) by proteomic analysis. In addition, putative antimicrobial peptides together with typical major components of wasp venom (venom allergen 5, mastoparan-like peptide, serine protease, and hyaluronidase) were identified in the EST Library. Additional in-depth annotation would be required for further characterization of many unidentified genes found in the EST library.
        574.
        2011.05 구독 인증기관·개인회원 무료
        Body and head lice (Pediculus humanus humanus and Pediculus humanus capitis, respectively) are typical ectoparasites of humans. They differ not only in the ecological habitat but also in the vector competence in spite of their conspecific nature. Only body lice transmit several bacterial pathogens to humans, including Bartonella quintana, Rickettsia prowazekii and Borrelia recurrentis. In this study, the proliferation rates of two model bacteria, a gram positive Staphylococcus aureus and a gram negative Escherichia coli, were determined following bacterial challenge by cuticular injection. Both bacteria proliferated rapidly in body lice at the early stage of bacterial challenge but not in head lice, suggesting that head lice have more sensitive immune responses to these bacteria. In vivo phagocytosis assay revealed that head lice have much higher phagocytic activity against E. coli than body lice whereas only slight differences in phagocytic activity against S. aureus were observed between the two lice species. Taken together, these findings suggest that the reduced phagocytosis activity of body lice contributes, at least in part, to their higher vector competence.
        575.
        2011.05 구독 인증기관·개인회원 무료
        The differences in the immune response between body lice, Pediculus humanus humanus, and head lice, Pediculus humanus capitis, were regarded as primary factors determining their differential vector competence. To find any differences in genetic components in immune system between body and head lice, whole genome sequences of head lice were determined by both SBS [sequencing by synthesis, Illumina Genome Analyzer (Illumina-GA)] and pyrosequencing (Roche GS FLX), and compared with the reference genome sequences of body lice. The short DNA reads from Illumina-GA (an average mapping depth of 50-fold) were aligned first to the body louse reference genome, to which Roche GS FLX DNA reads (an average depth of 2.5-fold) were subsequently assembled to make up gaps between mapped consensus. Total consensus showed a size of 114 Mb and a coverage of 96% of the published body louse genome sequences. From this head louse genome sequences, a total of 12,651 genes were predicted and used for comparing with the 10,775 genes previously reported from the body louse genome. The homolog analysis identified 873 head louse-specific genes and 422 body lice-specific genes. Comparison of immune response genes between both louse species showed head lice have more number of immune-related genes than body lice. Head lice were determined to possess all of the 107 immune-related genes reported in the previous study (Kim et al., 2011), suggesting that there is no difference in genetic make-up in terms of the 107 immune-related genes between body and head lice.
        576.
        2011.05 구독 인증기관·개인회원 무료
        Community structure of ground beetles in Seokmun- and Siwha-reclaimed lands was investigated with pitfall traps from 21 May to 1 November, 2010. Survey areas were divided by the status of reclamation, vegetation, and flooding frequency. Status of the Seokmun-reclaimed land in Chungcheongnam-do is the progress of conversion to rice paddy after completion, and then dominant plant is Secale cereals. For the Siwha reclaimed land in Gyeonggi-do, reclamation is ongoing, and thus Imperata cylindrica and Calamagrostis pigeios are dominant plants. Flooding was more frequent in Seokmun than in Siwha as 4 times and none, respectively. A total of 3,352 epigeic insects of 9 orders and 22,981 epigeic insects of 9 orders were collected from the Seokmun- and Siwha-reclaimed land, respectively. Collembola was the most abundant in each site. In ground beetle assemblage, 11 species belonging to 7 subfamilies Seokmun and 8 species belonging to 5 subfamilies in Siwha were identified from 183 and 101 collected ground beetles. Chlaenius pallipes (107 individuals, 58.5%) and Pheropsophus javanus (52 individuals, 28.4%) was dominant in Seokmun, while Harplus jureceki (37 individuals, 36.6%), Synuchus arcuaticollis (17 individuals, 16.8%), and Dolichus halensis halensis (17 individuals, 16.8%) was dominant in Siwha. The Shannon's index value was 1.147 and 1.671 in Seokmun and Siwha, respectively. Similarity by the Sørensen index between Seokmun and Siwha was 0.3158. In conclusion, community structure and seasonality of ground beetles were significantly different between two reclaimed lands, and this difference appears to be due to their different habitat conditions such as flooding frequency and progress of reclamation.
        577.
        2011.05 구독 인증기관·개인회원 무료
        Damages by Tyrophagus spp. (Acari: Acaridae) on horticultural crops were newly observed in recent years especially in organic culture greenhouses in Korea. The crops damaged by the mite species were Spinacia oleracea L. (spinach), Cucumis sativus (cucumber), and Phalaenopsis schilleriana (orchid). The spinach inner leaf growth was halted affected by the feeding of Tyrophagus similis at the early stage of the shoot emergence. The young leaves of the spinach bud had small holes and the leaves were deformed as they grew up. The surface of young cucumber fruits became shiny and soft at the early damage stage and the damaged surfaces became corky as the plants grew up. The mite from cucumber was identified as Tyrophagus neiswanderi Johnston & Bruce. In phalaenopsis orchid, the flower buds became yellow and dropped and the lower side of the leaves had white spots. The damages were caused by Tyrophagus putrescentiae.
        578.
        2011.05 구독 인증기관·개인회원 무료
        Field studies were conducted to assess potential effects of transgenic rice expressing Bacillus thuringiensis (Bt) CryIAc1 protein, which is highly effective the rice leafroller, Cnaphalocrocis medinalis, on the rice insect community in 2007 and 2008. Insects were sampled in non-Bt and Bt rice plots with a sweep net and a suction devise. A total of 64,256 individuals in 45 families and 11 orders (30,860 individuals in 43 families and 11 orders in the Bt-rice plots, and 33,396 individuals in 40 families and 11 order in the non-Bt rice plots) were captured and grouped by ecological functional guilds. Species diversity and richness were not significantly different between Bt-rice and non-Bt rice plots. The seasonal pattern of the insect community and the seasonal population fluctuation of insects were very similar between two plots. Collectively, the rice insect community was not influenced by the Bt-rice in the present study.
        579.
        2011.05 구독 인증기관·개인회원 무료
        Host plants of insect pest in turfgrass and ornamental tree, Popillia flavosellata (Coleoptera: Ruteridae) were investigated in golf courses and forest. Twenty six species in 18 families were observed to be fed on from this research and 22 species in 15 families were recorded newly host plants of P. flavosellata. Thus, total number of host plants of P. flavosellata were 49 species in 23 species. P. flavosellata adult mainly fed on flower of host plants. Seasonal prevalence of P. flavosellata adult was investigated in East Valley Country Club in Gwangju, Gyeonggii, Korea using Japanese beetle pheromone lure and a eugenol feeding attractant. Peak activity of P. flavosellata adult was nearby 20 June. Mean attracted number of P. flavosellata adult at peak day were 197.6 individuals/ trap/day at 2008 and 268.1 individuals at 2010. Occurrence of P. quadriguttata were very lower then P. flavosellata. Mean attracted number of P. quadriguttata adult at peak day were 17.5 individuals/trap/day at 2008 and 2.3 individuals at 2010 in same trap.
        580.
        2011.05 구독 인증기관·개인회원 무료
        The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid-resistant strain (IR) was over 200-fold more resistant to imidacloprid compared to a susceptible strain (S) as judged by LC50 values. The IR showed cross resistances to other neonicotinoid insecticides. IEF and 2DE analyses revealed that general esterase isozyme patterns in IR were almost identical to those of S. Nevertheless, a significantly overexpressed protein spot was detected in IR. To identify differentially expressed genes in IR, comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from both IR and S strains, which generated ca. 290 Mb reads for each strain. Generally, most nicotinic acetylcholine receptor subunit genes, such as alpha 2 and beta 1, were more transcribed in S than in IR. In contrast, only alpha 5 subunit gene was 1.8 fold more expressed in IR. Seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in IR. Therefore, this ABCC subfamily, a member of the MRP subfamily which is involved in multi-drug resistance, could be one of the main factors associated with imidacloprid resistance in A. gossypii.