Digitalization and the emergence of online video platforms changed the way people communicate and made new marketing opportunities. As mobile short-form video has unique characteristics, more people tend to consume and produce diverse content in the digital environment. The purpose of this study aims to better understand the influence of short-form videos from a fashion marketing standpoint and delineate the driving factors through story types. Specifically, by adopting common traits of short-form video content and story types based on Greimas’ narrative theory, this study explores customers’ intention toward fashion purchases and electronic word of mouth. In this context, this paper contributes to activating short-form video content as a tool to promote fashion brands and products but also opening up the possibility to further study short-form videos.

Circular leaf spot(CLS) disease causes considerable economic damage to persimmon(Diospyros kaki) in South Korea. Mycosphaerella nawae ascospores are the primary inoculum for CLS epidemics. In this study, we investigated the seasonal fluctuation of spore release and its relationship to environmental factors, based on spore trapping. We evaluated the seasonal pattern of released M. nawae ascospores in South Korea. During three persimmon growing seasons(2010 to 2012), we recorded the release of ascospores in two regions, Jinju and Gimhae, which are major producing regions of sweet persimmon in South Korea. The release of CLS ascospores was from the first week of May to the end of July. The maximum release of spores was observed in late June. A computer model used accumulated degree days to simulate ascospore release. The overall mean accumulated degree days, from 01 May to 50% ascospore release for the observed data(1174℃ days), was not significantly different from the predicted value of 1144℃ days. The mean differences between predicted and observed release percentages for the sampling periods were not significantly different from zero.

Postharvest apple rot causes severe economic losses and lowers apple quality, and is one of the most important limiting factors of apple exports. Apples with rot symptoms were sampled from Geochang, South Korea. Isolation of the causal fungus was performed by culturing small pieces of diseased tissues on potato dextrose agar. Two different rot genera, Fusarium and Alternaria, were identified according to their morphological characteristics. To confirm the identity of the causal fungus, we sequenced the DNA of the complete internal transcribed spacer(ITS) rDNA gene region and translation elongation factor 1-alpha(EF1-α) region. Koch’s postulates were supported by pathogenicity tests conducted on apple fruit. Based on mycological characteristics, molecular identification, and pathogenicity tests, the two fungi were identified as Fusarium tricinctum and Alternaria alternata. To the best of our knowledge, this is the first report of postharvest apple rot caused by F. tricinctum and A. alternata in South Korea.

사이드 스트림 방식의 막 모듈을 대상으로 유입 유량을 수직으로 균등하게 분포시킬 수 있는 방안을 CFD로 설계한 결과, 내부 유입 수리구조에 유공 격벽 을 설치함으로써 모듈내로의 유입유량은 표준편차 기준으로 약 40% 정도 감소 됨을 확인하였다. 또한 CFD 결과를 검증하고 사이드 스트림 막 모듈의 편중된 오염의 원인을 조사하기 위해 수행된 입자영상유속 측정 결과로부터 유입구 반대편 유공에서 막 모듈 내부로 들어오는 수체의 유속이 상대적으로 커 수체의 모멘텀이 유입구 측벽에 강한 전단력을 발생하지만 유입구 반대 측벽에서는 사류가 형성됨을 확인하였다.

Bacterial fruit blotch(BFB) of cucurbits caused by Acidovorax citrulli(Acc) continues to diminish fruit yields. The aim of this study was to address whether two genetically distinct populations of Acc are present in watermelon-growing fields in Korea. For this purpose, we used the enterobacterial repetitive intergenic consensus polymerase chain reaction(ERIC-PCR) profiling and substrate-utilization profiles. According to the results of ERIC-PCR, group I and II strains showed clearly differentiated PCR-based fingerprinting profiles. Differences between group I and II strains included amplification of unique, group-specific DNA fragments such as the 1.3-, 0.28-, and 0.25-kb fragments in ERIC-PCR. Acc stains belonging to group I did not use L-leucine, whereas group II strains did use the substrate. Our results support the genetic differentiation of Acc strains into two groups and demonstrate that Acc strains from both groups are previously existed in watermelon-growing fields in Korea. Information about the genetic diversity of Acc under the present study will help scientists and managers form strategies to control BFB.

시스타틴(cystatin: CST)은 C1A류 시스테인 단백질분해효소에 대한 경쟁적 가역억제자로서 동식물류에서 파파인과 같은 캐셉신을 억제 대상으로 작용하게 된다. 바이러스 유래 CST (CpBV-CST1)이 폴리드나바이러스의 일종인 CpBV (Cotesia plutellae bracovirus)에서 동정되었 다. 기존 연구는 이 유전자의 과발현이 배추좀나방(Plutella xylostella) 유충의 면역 및 발육을 교란한다는 것을 보여 주었다. 본 연구는 이 유전자 의 단백질 기능을 분석하기 위해 세균발현시스템을 이용하여 재조합단백질(rCpBV-CST1)을 형성하여 단백질분해효소에 대한 활성억제효과를 결정하고, 곤충의 면역과 발육에 대한 생리적 억제효과를 분석했다. 이 유전자 번역부위는 138 개 아미노산으로 약 15 kDa 크기의 단백질로 추 정되었다. CpBV-CST1이 먼저 pGEX 발현벡터에 재조합되고, BL21 STAR (DE3) competent cells에 형질전환된 후 0.5 mM IPTG로 4 시 간동안 과발현되었다. 분리된 재조합단백질은 파파인에 대한 뚜렷한 억제효과를 나타냈다. 이 재조합단백질은 파밤나방(Spodoptera exigua)에 대 해서 혈구소낭형성의 세포성 면역반응을 억제하고, 경구로 처리할 때 배추좀나방의 유충발육을 처리 농도에 비례하여 제한시켰다. 이상의 결과 는 CpBV-CST1이 해충 밀도 억제에 응용될 수 있음을 제시하고 있다.

A novel oxidant fumigation (NOF) is a commercial bleaching and disinfection agent. Recent study indicates its insecticidal activity. However, its exact mode of action to kill insects is not known. This study sets up a hypothesis that reactive oxygen species released from NOF is a main factor to kill insects. Plodia interpunctella is a lepidopteran insect pest infesting various stored grains. Both larvae and adults were susceptive to NOF. To test the hypothesis, we needed to identify antioxidant genes in P. interpunctella. Superoxide dismutase (SOD) and thioredoxin-peroxidase (Trx) were identified from P. interpunctella EST library using ortholog sequences of Bombyx mori. Both SOD and Trx were expressed in larvae of P. interpunctella expecially against oxidative stress induced by bacterial challenge. The bacterial challenge also induced some heat shock protein (HSP) genes. Similarly, different doses of NOF significantly induced both SOD and Trx genes. There results suggest that NOF at sublethal doses releases reactive oxygen species, which may be detoxified by the antioxidant activities of SOD and Trx of P. interpunctella.

Prostaglandins (PGs) mediate insect immune responses. However, their biosynthesis in insects is little understood due to lack of cyclooxygenase (COX) ortholog. This study aimed to identify PG-biosynthetic factor(s) in Spodoptera exigua, which has been a well-known insect in possessing immune responses mediated via PGs. Peroxidases (POXs) are a sister group of COX genes. Ten putative POXs (POX-A ∼POX-J) were expressed in S. exigua. Especially, expressions of POX-F and POX-H were inducible to bacterial challenge and expressed in hemocytes and fat body. Individual RNA interference (RNAi) of each of ten POXs was performed by hemocoelic injection of their specific double-strnaded RNAs (dsRNAs). Only RNAi of POX-F or POX-H specifically suppressed hemocyte-spreading behavior and nodule formation. Addition of PGE2 significantly nescued the immunosuppression in either dsRNA treatment of POX-F or POX-H. Structural analysis indicated that both POX-F and POX-H have conserved domain and residues corresponding to peroxinectin of Drosophila melanogaster, which mimics COX-like activity. These results suggest that POX-E and POX-H are involved in PG biosynthesis in S. exigua.

Immune mediators play crucial roles in amplifying the emergency signals with massive amounts of de novo synthesized mediators and relaying the specific recognition signals to the immune-associated target tissues. Eicosanoids are the representative immune mediators and synthesized from a polyunsaturated fatty acid (PUFA), arachidonic acid. Compared to mammalian systems, insects have relatively low levels of arachidonic acid in the biological membranes. This has raised a fundamental issue that eicosanoids may be not significant in insect system. Our previous chemical analysis suggests that the hemocytes of Spodoptera exigua have less than 5% arachidonic acid. We postulated that S. exigua may store arachidonic acid in other tissues, such as fat body. This analysed fatty acid compositions of two immune-associated tissues using a gas chromatography (GC) eguipped with FID detector or GC-MS. Our analysis of PUFA in the immune tissues suggests that insects maintain a low level of PUFA including arachidonic acid due to its evolutionary origin from the paleozoic era at which the oxygen level was 35%, compared to the present era 21%.

Phospholipase A2 (PLA2) catalyze the committed step for eicosanoid biosynthesis and releases arachidonic acid (AA), which is oxygenated into eicosanoids that mediate immune responses in insects. Thus, any inhibition of PLA2 activity would lead to a significant immuno suppression due to lack of eicosanoids. Among more than 15 families of PLA2s, group Ⅳ cytosolic PLA2 (cPLA2) has been mainly associated with the production of eicosanoids associated with immune responses. However, no cPLA2 has been reported in all invertebrates including insects. AcPLA2 candidate gene (SecPLA2) has been identified from a hemocyte transcriptome of the beet armyworm, Spodoptera exigua. RNA interference of SecPLA2 expression significantly reduced cellular immune responses of hemocytes. When the SecPLA2 was expressed and purified, the recombinant SecPLA2 catalyzed a substrate, phosphoatidyl choline, atsn-2 position. Its catalytic activity was sensitive to pH, temperature, and calciumlevel. Furthermore, there combinant SecPLA2 was specifically sensitive to a cPLA2-specificinhibitor, methyl arachidonyl fluorophosphonate.

Immune defense is indispensible for insect survival. However, uncontrolled and excessive immune responses would be highly detrimental and energy-consuming processes. An insect cytokine, plasmatocyte-spreading peptide (PSP), induces hemocyte-spreading behavior as well as activating phenoloxidase (PO) in the beet armyworm, Spodoptera exigua. A hemocyte transcriptome of S. exigua contains a partial sequence of a putative PSP-binding protein (SePSP-BP). SePSP-BP was expressed in all developmental stages especially in hemocytes and fat body. A quantitative RT-PCR showed that the bacterial infection significantly up-regulated the expression level of SePSP-BP. A double-stranded RNA specific to SePSP-BP (dsRNASePSP-BP) was injected and suppressed SePSP-BP expression even in response to bacterial challenge. The larvae treated with dsRNASePSP-BPsuffered high mortality to infection of nonpathogenic bacteria and prolonged high PO activity after the immune challenge. These results suggest that SePSP-BP may play a role in suppressing immune responses as a negative controller

아이코사노이드는 곤충의 다양한 세포성 면역 반응을 중개한다. 본 연구는 면역반응에 따라 혈구세포 밀도 변화에 대한 아이코사노이드의 새로운 중개 기능을 밝히기 위해 수행되었다. 파밤나방(Spodoptera exigua) 5령충은 세균 감염에 따라 2 시간이 지나면 총혈구수의 현격한 증가를 보였다. 이 총혈구수 증가는 주로 부정형혈구와 소구형혈구 밀도의 증가로 해석되었다. 파밤나방 유충에 phospholipase A2 (PLA2) 억제자인 dexamethasone을 처리하면 세균 처리에 의한 총혈구수 변화가 일어나지 않았다. 하지만 dexamethasone을 처리한 유충에 PLA2의 촉매산물인 arachidonic acid를 첨가하면 총혈구수 증가가 회복되었다. 이러한 혈구 밀도 변화에 원인으로서 아이코사노이드 종류를 추적하기 위해 cyclooxygenase (COX)의 억제자인 naproxene을 처리한 결과 총혈구수 증가가 억제되고, lipoxygenase (LOX)의 억제자인 esculetin을 처리하면 총혈구수 증가가 유지되어 COX 산물이 세균 침입에 따른 총혈구수 증가에 관여하는 것으로 나타났다. COX의 생산물인 prostaglandin E2(PGE2)를 세균 없이 단독으로 처리할 때도 총혈구수의 뚜렷한 증가를 나타냈다. 이러한 결과는 파밤나방의 세포성 면역반응 과정에서 총혈구수 증가를 중개하는 아이코사노이드의 새로운 기능을 제시하고 있다.

Insect blood cells, hemocytes, inhibit spreading behavior upon bacterial challenge to perform cellular immune responses. Hemocyte spreading is accomplished by cytoskeleton rearrangement, which is activated by various immune mediators, such as biogenic monoamins, plasmatocyte-spreading peptide(psp), and eicosanoids. However, little is known how these, immune mediators. acitvate hemocyte spreading behavior. A small G protein, Rac1, gene was identified in hemocytes of Spodoptera exiqua. Its expressed in most developmental stages accept egg and expecially expresses in hemocytes and fat body of Larval stage. In response to bacterial challenge, its expression was segnificantly up-regulated. However, RNA inteference (RNAi) of Rac1 expression inhibited hemocyte spreading behavior. under RNAi condition of Rac1, octopamine and psp failed to activate hemocyte spreading behavior. Interestingly, as addition of prostaglandinE2 to the RNAiconditioned Larval rescued the mediation of octopamine and psp. These results indicate that Rac1 is required for mediation of octopamine and psp on hemocytespreading behavior and suggest that Rac1 may activate eicosanoid biosnthesis.

As the immune reactions in human white blood cells of certain substances from insects to defend it when invaded by immune blood cells is increased. We experiment with changes in the total number of blood cells through the blood cells which increases and decreases, as well as to observe whether the immune response through any route is to evaluate what happens. Hemocyte population was analyzed in the last instar larvae of Spodoptera exigua. Granulocyte and plasmatocyte were predominant (>75%) types of hemocytes, whereas spherulocyte, prohemocyte, and oenocytoid hemocytes were observed in small densities (5~10%). Total hemocyte counts (THCs) were varied among different ages (day1-day5) of the last instar, in which day 3 larvae (L5D3) had the maximal density. Upon bacterial challenge to L5D3 larvae, THC was further enhanced within 2 h and then decreased to background level. This rapid THC increase in response to bacterial challenge was inhibited by injection with dexamethasone (1 ㎍ per larva). However, the addition of arachidonic acid reversed the inhibitory activity of dexamethasone and allowed the larvae to increase THC. This THC increase was mediated by cyclooxygenase products, but not by lipoxygenase products.