This article presents recent advancements in the development of flexible piezoresistive strain sensors based on carbon nanotubes (CNTs)–polymer composites, with particular attention to their electromechanical properties. Various fabrication approaches and material preparation of CNTs–polymer composites with improved piezoresistive performance are introduced. Moreover, the article presents the working principle of the piezoresistive sensors in terms of the tunneling effect and disconnection-reconnection mechanism. The sensing performances of recently reported applications are studied. This work also reveals that the CNTs–polymer composites have great potential for flexible, skin-mountable, and wearable electronics applications. Finally, possible challenges for the future developments of CNTs–polymer composites are discussed.

Since the late 1980s, information communication and technology (ICT) have reshaped the landscape of the tourism industry (Buhalis & Law, 2008). Thanks to the Web 2.0 technology, tourism practitioners have never been this close to their customers over social media platforms. According to Kaplan and Haenlein (2010), social media refers to “a group of Internet-based applications which build on the ideological and technological foundations of Web 2.0 and that allow the creation and exchange of User Generated Content” (p. 61). In line with this definition, electronic social networks, user-generated content aggregators, as well as location-based applications are all typical social media platforms, across which enable customers to create, edit, and share content. The increasingly growing social media platforms have greatly facilitated implementations of customer engagement strategies for organizations. As a psychological state, customer engagement is featured by interactive customer experiences with an organization, which encourage psychological, emotional, and physical investment a customer has in the organization (Harrigan, Evers, Miles, & Daly, 2017). In the tourism and hospitality context, customer engagement strategies are as critical in strengthening customer loyalty, trust, and brand evaluations (So, King, & Sparks, 2016). Useful insights have been gained relating to conceptualization and measurement scale of customer engagement, organizational and cultural obstacles to consumer engagement within hotel organizations (Chathoth et al., 2014), customer engagement in a social media context alongside the process of recognition (Cabiddu et al., 2014). Underlying the practical and theoretical significance of customer engagement lies the subjective nature of views on the social media platforms. Goh, Heng, and Lin (2014) recognized that engagement in social media brand communities positively lead to enhanced purchase expenditures through embedded information and persuasion. Quantitively, the persuasive effect of user generated information is at least 22 times more than that of marketer’s in terms of marginal effect. Although previous research has examined consequences of consumer engagement, there has been less attention paid to its causes. Meanwhile, as far as Brodie et al. (2011) were concerned, the persistency of consumer-brand engagement is contingent on an assessment of tangible and intangible costs against possible benefits such as product news and offers. Therefore, identification of these benefits can offer supplementary insights into current literature of consumer engagement. The current study utilizes the self-determination theory to uncover how engagement in social media activities is facilitated by consumers’ intrinsic motivators and what psychological benefits can consumer obtain from such engagement, as either psychological state or process (Brodie et al., 2011). Research subjects in this study are Chinese social media users. According to eMarketer’s (2017) estimated that more than 80 percent of Internet users in China (i.e., around 626 million people) accessed social networks regularly in 2017. The importance of tapping this massive market can never be overestimated.

Insect Growth Regulators (IGRs) are insecticides that disrupt the normal development of target insects by inducing symptoms such as premature molting or supernumerary larval stages. Juvenile hormone systems become the targets of two types of IGRs: the Juvenile Hormone Agonists (JHAs) and Juvenile Hormone Antagonists (JHANs). Pyriproxyfen is one of the chemical compounds widely used as JHA to control many kinds of insects while Kanakugiol is a plant-extracted compound which acts as JHAN. The small brown planthopper, Laodelphax striatellus, is one of the most serious pest insects of rice plants because it can transmit the rice stripe virus which often causes significant reduction of yield in the field. In order to analyze the differential gene expressions of L. striatellus upon JHA and JHAN treatment by using next generation sequencing technique, we sprayed Pyriproxyfen and Kanakugiol on 4th instar nymphs of L. striatellus respectively, and extracted total RNA for RNA-seq. The quality-filtered Illumina sequence reads of the control, JHA, and JHAN treated samples were mapped to the reference gene sequences by using the Bowtie2 software. Then the results of mapping by Bowtie2 were analyzed by eXpress software to quantity the differential gene expression.

ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in baculovirus life cycle, an ac78-deleted mutant AcMNPV, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype indicating that no infectious budded viruses (BVs) were produced. The defection in BV production was also confirmed by both viral titration and Western blot. However, viral DNA replication is unaffected. Analysis of BV and occlusion derived virus (ODV) revealed that AC78 is associated with both forms of the virions and is a structural protein located to viral envelope. Electron microscopy showed that ac78 also plays an important role in embedding of ODV into occlusion body. This study therefore demonstrates that AC78 is a late virion associated protein and is essential for the viral life cycle.

ORF11 (ac11) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly conserved gene of unknown function. To determine the role of ac11 in baculovirus life cycle, an ac11-knockout mutant AcMNPV, Ac11KO, was constructed. qPCR analysis revealed that ac11 is an early gene in the life cycle. After transfection into Spodoptera frugiperda cells, Ac11KO produced a single cell infection phenotype indicating that no infectious budded viruses (BVs) were produced. The defection in BV production was confirmed by both viral titration and Western blot. However, viral DNA replication is unaffected. Electron microscopy showed that ac11 is required for nucleocapsids envelopment to form ODV and their subsequent embedding into OB. This study therefore demonstrates that ac11 is an early gene which is essential for the viral life cycle.

Among hemipteran insects which is the most important insect vector of plant viruses, small brown planthopper, Laodelphax striatellus, transmits the rice stripe virus (RSV) causing rice stripe disease. For effective control of RSV, it is important to understand interaction between RSV and L. striatellus. Therefore, in this study, expressed sequence tag (EST) databases were generated based on 454 GS-FLX pyrosequencing for comparative transcriptome analysis between nonviruliferous and RSV-viruliferous L. striatellus. By comparing the two EST libraries, we showed that 108 host genes were significantly up-regulated and 28 host genes were significantly down-regulated in viruliferous insects. Interestingly, genes encoding ribosomal proteins were mainly up-regulated in viruliferous L. striatellus, whereas genes related to translation were concentrated in the downregulated cohort. These RSV-dependently regulated genes may have important function in the behavior of planthopper or the transmission of RSV.

Bacillus thuringiensis serovar mogi of a novel serogroup (H3a3b3d), which showed mosquitocidal activity against Anopheles sinensis and Culex pipiens pallens, was isolated from fallen leaves in Mungyeong city, Republic of Korea. In contrast to the complicated plasmid profiles of B. thuringiensis H3 serotype strains, the B. thuringiensis serovar mogi contained only megaplasmid (> 30 MDa) on which the toxin genes were occasionally located. Sequence analysis using 454-pyrosequencing revealed that the megaplasmid harbored at least seven putative cry genes, showing about 84%, 75%, 73%, 58%, 84%, 39% and 75% similarities in amino acid sequences with Cry27Aa, Cry19Ba, Cry20-like, Cry56Aa, Cry39ORF2, Cry8Ba and Cry40ORF2, respectively. These cry genes were cloned to the Escherichia coli-B. thuringiensis shuttle vector, pHT1K, and then introduced into an acrystalliferous B. thuringiensis Cry-B strain for further molecular characterization. To investigate the role of these genes in crystal production, the expression profiles of these toxin genes were analyzed by quantitative real-time PCR (qrtPCR) from the wild type strain as well as transformant strains. The results clearly indicate that the cry39orf2 was the dominant ingredient in the crystal. This novel 3a3b3d type strain, B. thuringiensis serovar mogi, could be used as a good resource for studying unknown mosquitocidal cry genes.

The baculovirus expression system is one of the most popular methods used for the production of recombinant proteins but has several complex steps which have proved inherently difficult to meet a multi-parellel process. We have developed a novel recombinant bacmid, bEasyBm that enabling easy and fast generation of pure recombinant virus without any purification step. In the bEasyBm, attR recombination sites were introduced to facilitate the generation of recombinant viral genome by in vitro transposition. Moreover, extracellular RNase gene from bacillus amyloliquefaciens, barnase, was expressed under the control of Cotesia plutellae bracovirus early promoter. Therefore, only when the barnase gene was replaced to gene of interest, the bEasyBm could replicate in host insect cells. When the bEasyBm was transposed with pDualBac-EGFP and pDualBac-LUC respectively, there were no non-recombinant backgrounds were detected from unpurified BmEasy-EGFP or BmEasy-LUC stocks. In addition, the resulting recombinant virus, BmEasy-EGFP, showed comparable level of EGFP expression efficiency with the plaque-purified recombinant virus, BmEGFP, which was constructed using bBmGOZA system. Based on these results, high-throughput condition for generation of multiple recombinant viruses in a time was established.

Varieties of Bacillus thuringiensis (Bt) crystal proteins, Cry proteins, have so far been found as one of the most successful biological control agents which are safe to natural environments for a long time. Recently, cry genes encoding these Cry proteins have been widely applied for construction of transgenic crops resistant to pest insects. In this study, through the 3D structure prediction and accompanying mutagenesis study for the Mod-Cry1Ac, 7 and 16 amino acid residues from domain I and II, respectively, responsible for its insecticidal activity against larvae of Spodoptera exigua and Ostrinia furnacalis were identified. To construct novel cry genes with improved insecticidal activity, we randomly mutated these 23 amino acid sequences by in vitro muti site-directed mutagenesis, resulting in totally 24 mutant cry genes. For further characterization, these mutant cry genes were expressed as a fusion protein with polyhedrin using baculovirus expression system. SDS-PAGE analysis of the recombinant polyhedra revealed that expressed Cry proteins was occluded into polyhedra and activated stably to 65 kDa by trypsin. In the further study, we plan to investigate their insecticidal activity against Plutella xylostella, S. exigua and O. furnacalis larvae.

In the transcriptome surveys of Laodelphax striatellus, several cDNA sequences showed a high level of similarities to the insect picorna-like virus genomes. Interestingly, there was no sequence similarity between picorna-like virus sequences from the RSV-viruliferous and those from the non-viruliferous L. striatellus. Picorna-like virus from the non-viruliferous L. striatellus was a geographical isolate of Himetobi P virus (HiPV). The genome of the HiPV was 9,272 nt in length excluding the poly(A) tail and contained two open reading frames (ORFs), which were separated by a 176 nt intergenic region that functions as an internal ribosome entry site (IRES). The 5' ORF encodes the non-structural proteins and the 3' ORF encodes the capsid proteins. The partial genomic RNA of the picorna-like virus from the RSV-viruliferous L. striatellus, LsPV-2, was 8,769 nt in length excluding the poly(A) tail and contained a single, large open reading frame (nt 1–8,535) encoding a 2,845 aa polyprotein. In terms of sequence similarity, identity, and genome organization, LsPV-2 resembled insect picornalike viruses belonging to the family Iflaviridae. A phylogenetic analysis based on RNA-dependent RNA polymerase (RdRp) sequence showed that LsPV-2 was most closely related to the deformed wing virus (DWV). The HiPV and LsPV-2 were incompatible each other in L. striatellus, suggesting that these two picorna-like viruses may have important functions in transmission of the RSV.

Plasmids from Bacillus thuringiensis have been implicated in pathogenicity as they carry the genes responsible for different types of diseases in mammals and insects. B. thuringiensis serovar mogi of a novel serogroup (H3a3b3d), which showed mosquitocidal activity against Anopheles sinensis and Culex pipiens pallens, was isolated from fallen leaves in Mungyeong city, Republic of Korea. In contrast to the complicated plasmid profiles of B. thuringiensis H3 serotype strains, the B. thuringiensis serovar mogi contained only megaplasmid (> 30 MDa) on which the toxin genes were occasionally located. Sequence analysis using 454-pyrosequencing revealed that the megaplasmid harbored at least seven putative cry genes, showing about 84%, 75%, 73%, 58%, 84%, 39% and 75% similarities in amino acid sequences with Cry27Aa, Cry19Ba, Cry20-like, Cry56Aa, Cry39ORF2, Cry8Ba and Cry40ORF2, respectively. These cry genes were cloned to the Escherichia coli-B. thuringiensis shuttle vector, pHT1K, and then introduced into an acrystalliferous B. thuringiensis Cry-B strain for further molecular characterization. This novel 3a3b3d type strain, B. thuringiensis serovar mogi, could be used as a good resource for studying unknown mosquitocidal cry genes.

ORF11 (ac11) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly conserved baculovirus gene whose homologs are found in all lepidoteran Group I NPV, but its function is unknown so far. To determine the role of ac11 in baculovirus life cycle, ac11 knock-out mutant, Ac11KO, was constructed using the plasmid capture system (PCS). Real-Time PCR analysis showed that ac11 transcript was first detected at 6 h post-infection (p.i.) and accumulated to maximum at 48 h p.i., indicating that ac11 is belong to late gene. When the genomic DNA of Ac11KO was transfected into Sf9 cells, viral replication was restricted to a cell transfected originally. While viral transmission of the Ac11KO was not observed in Sf9 cells, production of budded virus (BV) in Sf9 cells transfected with Ac11KO was observed by transmission electron microscopy (TEM). These results suggest that the ac11 is essential for AcMNPV to produce infective BV.

Although baculoviruses have a long history of safe use as specific, environmentally benign insect control agents, their use has been limited by several factors, especially their slow speed of action. In this study, we intended to improve the insecticidal activities of Autographa californica nucleopolyhedrovirus (AcMNPV) by expressing Kunitz-type toxin isolated from venoms of Bombus ignitus or Araneus ventricosus. For this, recombinant AcMNPVs, AcBi-KTT, AcAv-Tox1 and AcAv-Tox2 expressing Bi-KTT, Av-Tox1 and Av-Tox2, respectively, under the control of p10 gene promoter were constructed. While polyhedra produced by these recombinant viruses were identical to those of the wild-type AcMNPV in shape, their sizes were relatively smaller than those of the AcMNPV. Among recombinant viruses, AcBi-KTT and AcAv-Tox2 showed significant reduction in median lethal time (LT50) against Spodoptera exigua larvae. Especiaaly, these two viruses showed about 6.2~10-folds higher polyhedra production rate compared to that of the AcMNPV. These results suggested that Kunitz-type toxins from insect venom could be successfully applied to improve insecticidal activity of baculoviruses.

Among 154 putative ORFs of Autographa californica multiple nucleopolyhedrovirus (AcMNPV), ac78 and ac79 are highly conserved genes in baculovirus, but their functions in the virus life cycle have been unknown so far. To determine their roles in AcMNPV replication, knockout mutants, ac78KO and ac79KO, were constructed using the plasmid capture system (PCS). Real-Time PCR analysis showed that both of ac78 and ac79 transcripts were first detected at 6 hours post-infection, and accumulated to maximum at 24 hours post-infection, suggesting that both of ac78 and ac79 are belong to late gene. When the genomic DNA of ac78KO was transfected into Sf9 cells, viral replication was restricted to a single cell infection. These results demonstrated that the ac78 play an important role in BV production, and therefore is essential for AcMNPV to mount a successful infection. Whereas Sf9 cells infected with the ac79KO showed normal viral symptoms such as rounding and swelling, OBs were not observed from majority of infected cells. These results suggested that the ac79 might play an important role in OB production.

Autographa californica nucleopolyhedrovirus (AcMNPV) has a large doublestrand DNA genome of approximately 134 kbp and harbors 156 open reading frames (ORFs). To elucidate DNA replication cascade of AcMNPV, we developed a novel baculovirus genome that can be maintained in Escherichia coli as a plasmid and can infect susceptible lepidopteran insect cells. This genome, named bAc-MK, contains a mini-F replicon and a kanamycin resistance marker. Using a convenient Tn7 transposon-based system, pPCS-S, 55 single ORF-truncated mutants were generated by random insertion into bAc-MK genome. These single ORF-truncated mutants were independently transfected into Sf9 cells, 16 of them were found affecting viral replication since they defected in producing polyhedra. Furthermore, to verify the pathogenicity of the single ORF-truncated mutants, the remaining 39 mutants were subjected to bioassay to Spodoptera exigua 3rd instar larvae. Among them, ac9-, ac49-, ac103- and ac105-knockout mutants showed higher mortality compared to that of bAc-MK. These results suggested that these ORFs could be related to pathogenicity of AcMNPV.

Autographa californica nucleopolyhedrovirus (AcMNPV) has a large doublestrand DNA genome of approximately 134 kbp and comprises 156 open reading frames (ORFs). To elucidate DNA replication cascade of AcMNPV, we developed a novel baculovirus genome that can be maintained in Escherichia coli as a plasmid and can infect susceptible lepidopteran insect cells. This genome, named bAc-MK, contains a mini-F replicon and a kanamycin resistance marker. Using a convenient Tn7 transposon-based system, pPCS-S, which contains an ampicillin resistance gene, 56 single ORF-truncated mutants were generated by random insertion into bAc-MK genome. These single ORF-truncated mutants were independently transfected into Sf9 cells to verify viral replication. Interestingly, both lef-1 and p48 knockout mutants showed normal viral replication in infected cells, which are reported to essential for viral replication. These results suggest that these single ORF-truncated mutants are useful for elucidation of viral replication cascade.

To explore the relationship of species diversity and aboveground productivity in grazing ecosystem is very important to manage grassland. We used the four years' data to check this relationship and to look how abiotic factor affect species diversity and aboveground productivity. We found a good linear relationship between species diversity and aboveground productivity in all previous grazing sites, while no any relationship was found in the no grazing site. From our results, we concluded that drought affects aboveground productivity more than grazing, while heavy grazing affects species diversity more than drought in Inner Mongolian steppe.

Background : Invitro antioxidant activity, polyphenol and flavonoid aglycone contents in black and green tea products of balloon flower leaves were investigated to provide valuable information for the further development and utilization of resources of Platycodon grandiflorum. Methods and Results : Flavonoid aglycone contents were investigated using HPLC (SHIMADZU, Japan) with a hypersil ODS column (125 mm × 4 mm, 5-μm particle, HP). DPPH and ABTS radical scavenging activities were measured by method of Lee & Lee (2004) with slight modification. Antioxidant activity, polyphenol and flavonoid contents in green tea were significantly higher than these in black tea. PC analysis indicated that first principal components explained 79.9% of the total variability for five traits investigated. PC2 explained 19.7% of the variation. Conclusion : It can be concluded from these results that these characteristics can reveal the active compound variation of black and green tea products of balloon flower leaves. These results provide scientific evidence for the utilization of balloon flower leaves.