dInsects are the most abundant animals on Earth, and the microbiota within their guts play important roles by engaging in beneficial and pathological interactions with these hosts. In this study, we comprehensively characterized insect-associated gut bacteria of 305 individuals belonging to 218 species in 21 taxonomic orders, using 454 pyrosequencing of 16S rRNA genes. In total, 174,374 sequence reads were obtained, identifying 9,301 bacterial operational taxonomic units (OTUs) at the 3% distance level from all samples, with an average of 84.3 (؎97.7) OTUs per sample. The insect gut microbiota were dominated by Proteobacteria (62.1% of the total reads, including 14.1% Wolbachia sequences) and Firmicutes (20.7%). Significant differences were found in the relative abundances of anaerobes in insects and were classified according to the criteria of host environmental habitat, diet, developmental stage, and phylogeny. Gut bacterial diversity was significantly higher in omnivorous insects than in stenophagous (carnivorous and herbivorous) insects. This insect-order-spanning investigation of the gut microbiota provides insights into the relationships between insects and their gut bacterial communities.

BackgroundDNA barcoding, the analysis of sequence variation in the 5′ region of the mitochondrial cytochrome c oxidase I (COI) gene, has been shown to provide an efficient method for the identification of species in a wide range of animal taxa. In order to assess the effectiveness of barcodes in the discrimination of Heteroptera, we examined 344 species belonging to 178 genera, drawn from specimens in the Canadian National Collection of Insects.Methodology/Principal FindingsAnalysis of the COI gene revealed less than 2% intra-specific divergence in 90% of the taxa examined, while minimum interspecific distances exceeded 3% in 77% of congeneric species pairs. Instances where barcodes fail to distinguish species represented clusters of morphologically similar species, except one case of barcode identity between species in different genera. Several instances of deep intraspecific divergence were detected suggesting possible cryptic species.Conclusions/SignificanceAlthough this analysis encompasses 0.8% of the described global fauna, our results indicate that DNA barcodes will aid the identification of Heteroptera. This advance will be useful in pest management, regulatory and environmental applications and will also reveal species that require further taxonomic research.

Plant peroxidases (POD) reduce hydrogen peroxide (H 2 O 2 ) in the presence of an electron donor. Extracellular POD can also induce H 2 O 2 production and may perform a signiWcant function in responses to environmental stresses via the regulation of H 2 O 2 in plants. We previously described the isolation of 10 POD cDNA clones from cell cultures of sweetpotato (Ipomoea batatas). Among them, the expression of the swpa4 gene was profoundly induced by a variety of abiotic stresses and pathogenic infections (Park et al. in Mol Gen Genome 269:542-552 2003; Jang et al. in Plant Physiol Biochem 42:451-455 2004). In the present study, transgenic tobacco (Nicotiana tabacum) plants overexpressing the swpa4 gene under the control of the CaMV 35S promoter were generated in order to assess the function of swpa4 in planta. The transgenic plants exhibited an approximately 50-fold higher POD speciWc activity than was observed in control plants. Both transient expression analysis with the swpa4-GFP fusion protein and POD activity assays in the apoplastic washing Xuid revealed that the swpa4 protein is secreted into the apoplastic space. In addition, a signiWcantly enhanced tolerance to a variety of abiotic and biotic stresses occurred in the transgenic plants. These plants harbored increased lignin and phenolic content, and H 2 O 2 was also generated under normal conditions. Furthermore, they showed an increased expression level of a variety of apoplastic acidic pathogenesis-related (PR) genes following enhanced H 2 O 2 production. These results suggest that the expression of swpa4 in the apoplastic space may function as a positive defense signal in the H 2 O 2 -regulated stress response signaling pathway.

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Insects impact human health through vector-borne diseases and cause major economic losses by damaging crops and stored agricultural products. Insect-specific growth regulators represent attractive control agents because of their safety to the environment and humans. We identified plant compounds that serve as juvenile hormone antagonists (PJHANs). Using the yeast twohybrid system transformed with the mosquito JH receptor as a reporter system, we demonstrate that PJHANs affect the JH receptor, methoprene-tolerant (Met), by disrupting its complex with CYCLE or FISC, formation of which is required for mediating JH action. We isolated five diterpene secondary metabolites with JH antagonist activity from two plants: Lindera erythrocarpa and Solidago serotina. They are effective in causing mortality of mosquito larvae at relatively low LD 50 values. Topical application of two diterpenes caused reduction in the expression of Met target genes and retardation of follicle development in mosquito ovaries. Hence, the newly discovered PJHANs may lead to development of a new class of safe and effective pesticides. Diseases transmitted by insects result in a million deaths per year (1), and insect infestation leads to annual losses of agricultural products worth billions of US dollars (2). The high toxicity of currently available insecticides presents environmental and health risks, and growing resistance and cross-resistance of insects to these existing insecticides gravely complicates the situation. Hence, there is an urgent need to develop novel effective insecticides.Insect growth regulators (IGRs) have been devised based on insect-specific functions. Three major classes of IGRs are commercially available (3). These IGRs include juvenile hormone (JH) agonists (methoprene and pyriproxyfen), ecdysone agonists (halofenozide and tebufenozide), and chitin synthase inhibitors (buprofezine). They possess low off-target toxicity and environmental danger and have been used to control pests. JHbased IGRs are of particular interest because JH is an insectspecific hormone. JH agonists (JHAs) disrupt insect endocrine regulation, causing abnormal development and larval fatality (4). However, JHAs have limitations in the scope of their applications because they mimic and enhance the JH mode of action. Theoretically, JH antagonists (JHANs) could be used as a powerful alternative, but no effective JHANs have yet been developed.Recent studies identified methoprene-tolerant (Met) as the JH receptor (5, 6). Met is a member of the family of basic helixloop-helix (bHLH)-Per-Arnt-Sim (PAS) transcription factors that requires homo-or heterodimerization for DNA binding and transcriptional regulation (7). In the Aedes aegypti mosquito, Met forms a heterodimer with other bHLH-PAS factors, the steroid receptor coactivator (SRC/FISC), or Cycle (CYC) in a JHdependent manner (8, 9). JH-mediated Met-CYC binding has been quantitatively simulated using the two-hybrid yeast β-galactosidase assay in a yeast cell, Y187 (9). Thus, it is possible to test both J...

A Gram-stain-negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, BS-B2T, which was isolated from a tidal flat sediment at Boseong in South Korea, was characterized taxonomically. Strain BS-B2T grew optimally at 30 °C, at pH 7.0–8.0 and in the presence of 2.0 % (w/v) NaCl. The novel strain exhibited highest 16S rRNA gene sequence similarity (97.4 %) to Marivita geojedonensis DPG-138T. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences revealed that strain BS-B2T is closely related to Primorskyibacter sedentarius KMM 9018T, showing 96.5 % sequence similarity. Strain BS-B2T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the predominant fatty acid. The polar lipid profile of strain BS-B2T comprised phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid as major components, and differentiated it from the type strains of P. sedentarius and M. geojedonensis . The DNA G+C content of strain BS-B2T was 62.2 mol%. Differential phenotypic properties, together with the phylogenetic and chemotaxonomic data, demonstrated that strain BS-B2T can be distinguished from phylogenetically related genera as well as P. sedentarius and M. geojedonensis . On the basis of the data presented, strain BS-B2T is considered to represent a novel species of a new genus, for which the name Aestuariivita boseongensis gen. nov., sp. nov. is proposed. The type strain of Aestuariivita boseongensis is BS-B2T ( = KCTC 42052T = CECT 8532T).

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BackgroundDNA barcoding uses a 650 bp segment of the mitochondrial cytochrome c oxidase I (COI) gene as the basis for an identification system for members of the animal kingdom and some other groups of eukaryotes. PCR amplification of the barcode region is a key step in the analytical chain, but it sometimes fails because of a lack of homology between the standard primer sets and target DNA.ResultsTwo forward PCR primers were developed following analysis of all known arthropod mitochondrial genome arrangements and sequence alignment of the tRNA-W gene which was usually located within 200 bp upstream of the COI gene. These two primers were combined with a standard reverse primer (LepR1) to produce a cocktail which generated a barcode amplicon from 125 of 141 species that included representatives of 121 different families of Hexapoda. High quality sequences were recovered from 79% of the species including groups, such as scale insects, that invariably fail to amplify with standard primers.ConclusionsA cocktail of two tRNA-W forward primers coupled with a standard reverse primer amplifies COI for most hexapods, allowing characterization of the standard barcode primer binding region in COI 5' as well as the barcode segment. The current results show that primers designed to bind to highly conserved gene regions upstream of COI will aid the amplification of this gene region in species where standard primers fail and provide valuable information to design a primer for problem groups.