검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 76

        21.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Motile aeromonad septicaemia (MAS) mostly caused by Aeromonas hydrophila is a disease of high economic impact in freshwater organism. This study examined the seroconversion and seroprotection of formalinised local isolates of Aeromonas hydrophila in the Clarias gariepinus administered via different routes. Highly virulent Aeromonas hydrophila was treated with 40v/v formalin for 24 h. Bacterin was suspended to 0.5 McFarland standard and utilized to immunize Clarias gariepinus of 400±20 g in three groups with 50 samples each via three routes of administration. Antibody measurement taken at regular intervals before and after vaccination revealed a significantly higher antibody values in all routes compared to the control and difference was noticed at all intervals. Relative percent survival was 71.43, 62.86 and 57.14 intraperitoneal, intramuscular and immersion routes, respectively. Correlation analysis established a strong and direct relationship in the antibody generation through route of administration and efficacy of vaccine. This local vaccine was able to confer a high degree of immunity on Clarias gariepinus and can therefore be used to vaccinate against MAS.
        4,000원
        22.
        2019.04 구독 인증기관·개인회원 무료
        Three ambrosia beetle species, Xyleborus glabratus, Monarthrum mali, and Euwallacea fornicatus belong to subfamily, Scolytinae, showing similar morphology and body size, but their flight capability and patterns showed species-specific. Body length of Xyleborus glabratus and Monarthrum mali was negatively correlated with flight capabilities; shorter beetles performed longer average flights, longer single flights, total flight distance, and total flight time. Elytral length also was negatively correlated with flight distance in X. glabratus and M. mali. Conversely, only average flight time of E. fornicatus was positively correlated with body length, pronotal width, and elytral length. Body length had no effect on the flight velocity of any of the three beetle species examined. Therefore, our results indicate that body size characteristics of ambrosia beetles differentially influence on their dispersal by species.
        23.
        2018.10 구독 인증기관·개인회원 무료
        Trails of the convergence ladybird negatively affected the brown citrus aphid population. On 3 days after treatment of ladybird trails, the population growth rate of the brown citrus aphid on treatment and control swingle flushes in the test tube were –0.1848 and –0.0385, respectively. In pot experiments, there were no significant differences in population growth rates between treatment and control swingle plants on 3 and 7 days after treatment of ladybird trails. But, on 10 days after treatment, each population growth rate was -0.0415 and 0.1125, respectively so there was significantly different statistically. Thus, our result support the potential practical application of ladybird trails as an effective control agent for managing of herbivorous insect pests in citrus groves.
        24.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The incidence of freshwater algal bloom has been increasing globally in recent years and poses a major threat to environmental health. Cyanobacteria are the major component of the bloom forming community that must be monitored frequently. Their morphological identities, however, have remained elusive, due to their small size in cells and morphological resemblances among species. We have analyzed molecular diversity and seasonal changes of cyanobacteria in Paldang Reservoir, Korea, using morphological and 16S rRNA pyrosequencing methods. Samples were collected at monthly intervals from the reservoir March-December 2012. In total, 40 phylotypes of cyanobacteria were identified after comparing 49,131 pyrosequence reads. Cyanobacterial genera such as Anabaena, Aphanizomenon, Microcystis and Synechocystis were predominantly present in samples. However, the majority of cyanobacterial sequences (65.9%) identified in this study were of uncultured origins, not detected morphologically. Relative abundance of cyanobacterial sequences was observed as high in August, with no occurrence in March and December. These results suggested that pyrosequencing approach may reveal cyanobacterial diversity undetected morphologically, and may be used as reference for studying and monitoring cyanobacterial communities in aquatic environments.
        4,600원
        27.
        2017.04 구독 인증기관·개인회원 무료
        In order to establish symbiotic host-bacterial relationships, symbionts in insects evolved a mechanism to overcome host immune responses. Here we provide the resistance of symbiotic bacteria on the insect immune system. As a result, through the transposon mutagenesis, we found a salivary gland (SG) susceptible mutant. The disrupted gene was identified as nlpB involved in lipoprotein synthesis. The nlpB, bla double deletion mutant was sensitive to SG like nlpB-Tn5 inserted mutant. This mutant increases outer membrane permeability. It provides an explanation for SG susceptibility, because the antimicrobial peptide in SG would be able to translocate across the outer membrane more easily than in the wild type. These results indicate that nlpB and bla are likely to be important factors in terms of determining resistance against SG of Riptortus that is connected with the successful colonization of the Riptortus midgut.
        28.
        2017.04 구독 인증기관·개인회원 무료
        Recent studies suggested that gut symbionts modulate insect development and reproduction. However, how gut symbionts modulate host physiologies and what types of molecules are involved in these changes are still unclear. When we analyzed hemolymph proteins and transcriptional levels of host insects, hexamerin-α (Hex-α), hexamerin-β (Hex-β) and vitellogenin-1 (Vg-1) were highly expressed in symbiotic insects (Sym) compared to aposymbiotic insects (Apo). Depletion of Hex-β by RNA interference in 2nd Sym-nymphs delayed adult emergence, whereas Hex-α and Vg-1 RNA interference in 5th nymphs decreased reproduction of female insects and caused loss of color of laid eggs. Also, the levels of JHSBIII of Riptortus host were 3-fold higher in the Sym-female insects compared to the Apo-insects. These results demonstrate that the Burkholderia gut symbiont modulates host development and egg production through regulating the expression of three host storage proteins by controlling of brain hormone.
        29.
        2017.04 구독 인증기관·개인회원 무료
        Five phaP family genes and one phaR gene have been identified in the genome of Burkholderia gut symbiont. PhaP proteins function as surface proteins of polyhydroxyalkanoate (PHA) granules, and PhaR protein acts as a negative regulator of PhaP biosynthesis. To address the biological roles of four phaP family genes (phaP1, phaP2, phaP3, and phaP4) and the phaR gene during insect-gut symbiont interaction, these Burkholderia mutants were fed to the second instar nymph. The ΔphaR mutant decreased the colonization ability in the host midgut compared to wild-type Burkholderia cells and negatively affected the host insect’s fitness compared with wild-type infected host. These results demonstrate that PhaR plays an important role in the biosynthesis of PHA granules and it is significantly related to the colonization of the Burkholderia gut symbiont in the host insects’ midgut
        30.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polarbear is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic in ation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1,274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.
        3,000원
        31.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present an ongoing study of the complete sample of supernova remnants (SNRs) and candidates in the Magellanic Clouds. 108 objects in both Clouds are considered to be either SNR or reliable candidates. This represents the most complete sample of all known SNRs in any galaxy. It therefore allows us to study SNR population properties such as the age-diameter (Age-D) relation. Here, we show that this Age-D relation is strongly dependant on the local environment in which SNRs are residing.
        4,000원
        32.
        2015.06 구독 인증기관·개인회원 무료
        Consumers and sources are embedded in cultural contexts that influence how those sources are read. We examine how consumers stigmatized for being fat collectively read advertisements for luxury fashion brands featuring plus-sized sources. We unveil individual and cultural resources stigmatized consumers rely on to collectively develop readings of advertising sources.
        33.
        2015.06 구독 인증기관 무료, 개인회원 유료
        This paper presents a study of the port logistics activities at the port of Santos (Brazil). The study follows a qualitative approach and it is based on in-depth interviews with some key actors from Santos port logistics chain. Based on these interviews, the main dysfunctions and improvement opportunities associated to the container port logistics processes at Santos were identified. The results show that the main dysfunctions are related to the existing information flows. Due to this, a new information flow related to the studied port is proposed and some probable results of the implementation are identified. The findings contribute both to the studied port and to the academic community, as the number of studies addressing port logistics activities is still limited.
        4,600원
        35.
        2014.10 구독 인증기관·개인회원 무료
        The Riptortus pedestris-Burkholderia symbiotic system is a promising model for understanding molecular mechanism of symbiosis. In previous studies, the Burkholderia symbiont has been shown to play important biological roles in the growth and fitness of host R. pedestris. The Burkholderia symbiont, one of bacteria found in the soil, is the only bacterium that can colonize the symbiotic midgut region of R. pedestris. However, the molecular mechanism of host selectivity for the Burkholderia symbiont remains unknown. To determine where the selection occurs, we firstly compared initial infectivity of different mid-gut regions after oral infection of Escherichia coli and Burkholderia. Interestingly, E. coli were not detected in any regions of mid-gut, while Burkholderia could reach to the posterior region of mid-gut. Therefore, we hypothesized that host selectivity for the Burkholderia symbiont is occurred in the salivary gland. To address this hypothesis, we treated E. coli and Burkholderia with lysate of salivary gland and examined their survival by estimation of colony forming unit (CFU) on the plate. We found that E. coli, but not Burkholderia, was susceptible to the lysate of salivary gland. To determine molecular basis of the selective mechanism in the salivary gland, we analyzed antimicrobial proteins (AMPs) from lysate of salivary gland. we identified three AMPs, namely rip-trialysin1, rip-trialysin2 and lysozyme and further purified rip-trialysin1 and rip-trialysin2. When E. coli and Burkholderia were treated with rip-trialysin1 and rip-trialysin2, rip-trialysin1 exhibited little antimicrobial activity, but rip-trialysin2 exhibited antimicrobial activity. Furthermore, we found that E. coli was susceptible, but Burkholderia is resistant to commerciallypurchased egg white lysozyme. Our results suggest that R. pedestris salivary gland provides a chance of selection for the Burkholderia symbiont and lysozyme in salivary gland seems to play an important role for the selection of gut symbiont.
        36.
        2014.10 구독 인증기관·개인회원 무료
        Biological properties of antimicrobial peptides (AMPs) of hemimetabolous insect are poorly characterized in innate immunity field. To investigate the biochemical properties of hemimetabolous insect’s AMPs, we purified the pyrrhocoricin-like AMP from the hemolymph of Riptortus pedestris and then named as riptocin. We successfully determined the primary protein structure and its cDNA sequence. Interestingly, the determined cDNA revealed that riptocin precursor is composed of 12 repeating units of active riptocins, which implied that riptocin precursor might require to be processed to generate active riptocins by several unidentified processing enzymes. In order to characterize the bio-processing mechanisms of riptocin precursor, we generated the antibody against active riptocin. Using quantitative PCR and Western blot analyses, we showed that gene of riptocin was started to express from the fatbody after three hours post bacterial infection. To address our hypothesis that active riptocin is generated from riptocin precursor by several processing enzymes, we need to obtain the riptocin precursor. Currently, we are expressing the recombinant riptocin precursor using in vitro translation system. Meanwhile, we investigated whether naive hemolymph (naive HL), which may contain precursor riptocin, can generate active riptocin when riptocin precursor was co-incubation with bacteria-challenged hemolymph (active HL), which may contain all processing enzymes. Actually, when naive HL was incubated with active HL, antimicrobial activity was dramatically increased, suggesting that processing enzymes in active HL may induce processing of riptocin precursor to generate active riptocins.
        37.
        2014.10 구독 인증기관·개인회원 무료
        Riptortus pedestris possesses Burkholderia as gut symbiont in a symbiotic organ M4 midgut. To answer why Burkholderia symbionts are not eliminated by Riptortu s immune responses, we developed two hypotheses: (i) Burkholderia symbionts do not activate host innate immunity, or (ii) Burkholderia symbionts are resistant to th e host immune responses. For the first hypothesis, we compared the antimicrobial activities of the cultured Burkholderia-injected hemolymph and symbiotic Burkhol deria-injected hemolymphs. As a result, the symbiotic Burkholderia induced antim icrobial activity like the cultured Burkholderia, indicating the symbiotic cells are st ill immunogentic to host. However, when the activated hemolymph was treated to the Burkholderia cells, the symbiotic Burkholderia showed much higher susceptibi lity than the cultured Burkholderia. To understand molecular basis of these results, we purified antimicrobial peptides (AMPs) from Riptortus hemolymph. Similarly, the symbiotic Burkholderia exhibited the high susceptibility to the purified AMPs, riptocin and rip-defensin. To understand how symbiotic Burkholderia can survive in host in spite of their immuno-susceptibility, we examined the AMP expression i n the M4 midgut. Interestingly, the expression of AMPs is suppressed in the M4 mi dgut in comparison to that of the fat body. Finally, we proposed that the immuno-su sceptibility of Burkholderia symbiont helps them to retain in the symbiotic organ. Our in vivo data showing the rapid clearance of the symbiotic Burkholderia after inj ection to host Riptortus supports our proposal.
        38.
        2014.10 구독 인증기관·개인회원 무료
        Symbiotic bacteria are common in insects. Because symbiotic bacteria are known to intimately affect the various aspects of insect host biology, ideally insects can be controlled by manipulating their symbiont. However, the attempts to control insects through their symbiont have been very limited. The paucity of the insect pest control using their symbiont is most likely due to the poor understanding of the symbiotic interactions between host insect and symbiont, which is attributed to the difficulty in cultivation of insect symbionts. However, the recently established bean bug, Riptortus pedestris, symbiotic system provides good opportunities to study insect’s symbiont in molecular level through their cultivable symbionts. Bean bugs acquire genus Burkholderia cells from environment and harbor them as their gut symbionts in the specialized posterior midgut. The genome of the Burkholderia symbiont was sequenced, and the genomic information has been used to generate the genetically manipulated Burkholderia symbiont strains. After orally administering the mutant Burkholderia symbionts into bean bugs for symbiotic association, the bacterial colonization levels in the host gut and host phenotypes were analyzed. As a result, we have identified novel symbiotic factors necessary for establishing successful association with host. Our recent understandings on the bacterial symbiotic factors demonstrate a great possibility to control the bean bug pest using genetically modified Burkholderia symbiont.
        39.
        2014.04 구독 인증기관·개인회원 무료
        The Riptortus-Burkholderia symbiosis is a newly emerging insect-bacterium symbiotic system. This symbiosis system has a good merit as an experimental model system to produce the non-symbiotic (apo) and symbiotic (sym) host insect. In recent reported papers, the symbionts play important biological roles for the host insects. Meanwhile, juvenile hormone (JH) is one of major hormone synthesized corpora allata(CA) to control many physiology of insect. However, the study for cross-talk mechanism between symbionts and host hormones to control important physiological phenomenon of insects is almost none. In this study, we found that Riptortus speed up adult emerging and increase egg laying on presence of symbiont Burkholderia. Also we found that hexamerin proteins, which were controlled the expression by JH, were accumulated in sym-Riptortus hemolymph compare with apo-Riptortus. According as combined results, we hypothesized that the gut symbiont Burkholderia can control JH titer to conclude out beneficial effects such as development and reproduction of R. pedestris. To verify this hypothesis, we examined measurement of JH titer, expression of hexamerins as JH response genes and RNAi for hexamerin protein during whole Riptortus life on presence or absence of symbiont Burkholderia. All results demonstrated that gut symbiont controlled JH titer of Riptortus. Controlled JH amount by symbiont Burkholderia in host midgut regulated hexamerin protein expression for speeding up adult emerging and increasing egg production.
        40.
        2014.04 구독 인증기관·개인회원 무료
        The Riptortus (stinkbug) has a specialized symbiotic organ, M4 midgut, to harboring symbiont Burkholderia. M4 midgut is located in abdomen and surrounded with insect hemolymph. Recently our group demonstrated that symbiotic Burkholderia showed different physiology after adapting in M4 gut compare with in vitro cultured Burkholderia. And population of symbiotic Burkholderia in the M4 midgut is regulated by special organ. However, the molecular mechanism to prevent spreading and migrating symbiont bacteria to other host tissues from symbiotic organ is not clear. Therefore, we assumed that symbiont Burkholderia are susceptible to host humoral immunity after established infection in M4 midgut to prevent spreading and migrating into the other host tissues through Riptortus hemolymph. To prove this assuming, we tested the susceptibility and survival rate of symbiont Burkholderia in hemolymph of Riptortus in vitro and in vivo. We also examined the susceptibility of symbiont Burkholderia using purified antimicrobial peptides (AMP), pyrrhocoricin-like, thanatin-like and defensin-like AMPs. Finally, we tested inducing ability for AMPs by systemic infection of symbiotic Burkholderia. Gene expression of purified AMPs was not different after systemic infection of both symbiont and in vitro cultured Burkholderia. Surprisingly, in vitro cultured Burkholderia resisted on bacteria injected hemolymph and purified AMPs but symbiont Burkholderia were highly susceptible in bacteria injected hemolymph and purified AMP. These results suggest that symbiont Burkholderia can't survive in the hemolymph after escaping symbiotic organ. Moreover, humoral immunity of host Riptortus is important to prevent spreading and migrating symbiont Burkholderia into the other host tissue or organ from symbiotic organ.
        1 2 3 4