Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick–host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host ‘questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.

Although eusociality evolved independently within several orders of insects, research into the molecular underpinnings of the transition towards social complexity has been confined primarily to Hymenoptera (for example, ants and bees). Here we sequence the genome and stage-specific transcriptomes of the dampwood termite Zootermopsis nevadensis (Blattodea) and compare them with similar data for eusocial Hymenoptera, to better identify commonalities and differences in achieving this significant transition. We show an expansion of genes related to male fertility, with upregulated gene expression in male reproductive individuals reflecting the profound differences in mating biology relative to the Hymenoptera. For several chemoreceptor families, we show divergent numbers of genes, which may correspond to the more claustral lifestyle of these termites. We also show similarities in the number and expression of genes related to caste determination mechanisms. Finally, patterns of DNA methylation and alternative splicing support a hypothesized epigenetic regulation of caste differentiation.

Silicon (Si) is important in plant defenses that operate in a direct manner against herbivores, and work in rice (Oryza sativa) has established that this is mediated by the jasmonate signaling pathway. Plant defenses also operate indirectly, by the production of herbivore induced plant volatiles (HIPVs) that attract predators and parasitoids of herbivores. These indirect defenses too are mediated by the jasmonate pathway but no earlier work has demonstrated an effect of Si on HIPVs. In this study, we tested the effect of Si supplementation versus Si deprivation to rice plants on subsequent HIPV production following feeding by the important pest, rice leaffolder (Cnaphalocrocis medinalis). Gas chromatography–mass spectrometry analyses showed lower production of α-bergamotene, β-sesquiohellandrene, hexanal 2-ethyl, and cedrol from +Si herbivore-infested plants compared with -Si infested plants. These changes in plant chemistry were ecologically significant in altering the extent to which parasitoids were attracted to infested plants. Adult females of Trathala flavo-orbitalis and Microplitis mediator both exhibited greater attraction to the HIPV blend of +Si plants infested with their respective insect hosts compared to -Si infested plants. In equivalent studies using RNAi rice plants in which jasmonate perception was silenced there was no equivalent change to the HIPV blend associated with Si treatment; indicating that the effects of Si on HIPVs are modulated by the jasmonate pathway. Further, this work demonstrates that silicon alters the HIPV blend of herbivore-infested rice plants. The significance of this finding is that there are no earlier-published studies of this phenomenon in rice or any other plant species. Si treatment to crops offers scope for enhancing induced, indirect defenses and associated biological control of pests because parasitoids are more strongly attracted by the HIPVs produced by +Si plants.

454 Pyrosequencing was used to characterize the expressed genes from the synganglion and associated neurosecretory organs of unfed and partially fed virgin and mated replete females of the American dog tick, Dermacentor variabilis. A total of 14,881 contiguous sequences (contigs) was assembled, with an average size of 229 bp. Gene ontology terms for Level 2 biological processes were assigned to 4366 contigs. Seven acetylcholinesterases, a muscarinic acetylcholine (ACh) receptor, two nicotinic ACh receptor β-subunits, two ACh unc-18 regulators, two dopamine receptors, two gamma aminobutyric acid (GABA) receptors, two GABA transporters, two norepinephrine transporters and an octopamine receptor are described. Microarrays were conducted to examine global gene expression and quantitative real-time polymerase chain reaction was used to verify expression of selected neuropeptides. Hierarchical clustering of all differentially expressed transcripts grouped part-fed and replete ticks as being more similar in terms of differentially expressed genes with unfed ticks as the outgroup. Nine putative neuropeptides (allatostatin, bursicon-β, preprocorazonin, glycoprotein hormone α, insulin-like peptide, three orcokinins, preprosulphakinin) and a gonadotropin releasing hormone receptor were differentially expressed, and their developmental expression and role in reproduction was investigated. The presence of eclosion hormone, corazonin and bursicon in the synganglion, which in insects regulate behaviour and cuticle development associated with moulting, suggest that this system may be used in ticks to regulate blood feeding, cuticle expansion and development related to female reproduction; adult ticks do not moult.

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Oxidative stress is implicated as an important factor in the development of Alzheimer's disease (AD). In the present study, we have investigated the effects of edaravone (9mg/kg, 3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, in a streptozotocin (STZ-3mg/kg) induced rat model of sporadic AD (sAD). Treatment with edaravone significantly improved STZ-induced cognitive damage as evaluated in Morris water maze and step-down tests and markedly restored changes in malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE) adducts, hydroxyl radical (OH), hydrogen peroxide (H2O2), total superoxide dismutase (T-SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and protein carbonyl (PC) levels. In addition, histomorphological observations confirmed the protective effect of edaravone on neuronal degeneration. Moreover, hyperphosphorylation of tau resulting from intracerebroventricular streptozotocin (ICV-STZ) injection was decreased by the administration of edaravone. These results provide experimental evidence demonstrating preventive effects of edaravone on cognitive dysfunction, oxidative stress and hyperphosphorylation of tau in ICV-STZ rats. Since edaravone has been used for treatment of patients with stroke, it represents a safe and established therapeutic intervention that has the potential for a novel application in the treatment of age-related neurodegenerative disorders associated with cognitive decline, such as AD.

BackgroundSerine protease inhibitors (SPIs) have been found in all living organisms and play significant roles in digestion, development and innate immunity. In this study, we present a genome-wide identification and expression profiling of SPI genes in the diamondback moth, Plutella xylostella (L.), a major pest of cruciferous crops with global distribution and broad resistance to different types of insecticides.ResultsA total of 61 potential SPI genes were identified in the P. xylostella genome, and these SPIs were classified into serpins, canonical inhibitors, and alpha-2-macroglobulins based on their modes of action. Sequence alignments showed that amino acid residues in the hinge region of known inhibitory serpins from other insect species were conserved in most P. xylostella serpins, suggesting that these P. xylostella serpins may be functionally active. Phylogenetic analysis confirmed that P. xylostella inhibitory serpins were clustered with known inhibitory serpins from six other insect species. More interestingly, nine serpins were highly similar to the orthologues in Manduca sexta which have been demonstrated to participate in regulating the prophenoloxidase activation cascade, an important innate immune response in insects. Of the 61 P.xylostella SPI genes, 33 were canonical SPIs containing seven types of inhibitor domains, including Kunitz, Kazal, TIL, amfpi, Antistasin, WAP and Pacifastin. Moreover, some SPIs contained additional non-inhibitor domains, including spondin_N, reeler, and other modules, which may be involved in protein-protein interactions. Gene expression profiling showed gene-differential, stage- and sex-specific expression patterns of SPIs, suggesting that SPIs may be involved in multiple physiological processes in P. xylostella.ConclusionsThis is the most comprehensive investigation so far on SPI genes in P. xylostella. The characterized features and expression patterns of P. xylostella SPIs indicate that the SPI family genes may be involved in innate immunity of this species. Our findings provide valuable information for uncovering further biological roles of SPI genes in P. xylostella.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3583-z) contains supplementary material, which is available to authorized users.

Abstract. BioUD is an arthropod repellent that contains the active ingredient 2-undecanone originally derived from wild tomato plants. Repellency of BioUD was compared with five commercially available arthropod repellents against the ticks Amblyomma americanum (L.) and Dermacentor variabilis Say in two-choice bioassays on treated versus untreated cotton cheesecloth. Overall mean percentage repellency against both species was greatest for and did not differ significantly between BioUD (7.75% 2-undecanone) and products containing 98.1% DEET, 19.6% IR3535, and 30% oil of lemon eucalyptus. Products containing 5% and 15% Picaridin and 0.5% permethrin were also repellent compared with untreated controls but to a lesser degree than BioUD. The four most active repellents at the same concentrations used before were directly compared in head-to-head bioassays on cotton cheesecloth. BioUD provided significantly greater overall mean percentage repellency than IR3535 for A. americanum and D. variabilis . BioUD was significantly more repellent than oil of lemon eucalyptus for A. americanum but did not differ significantly in repellency against D. variabilis . No statistically significant difference in overall mean percentage repellency was found between BioUD and DEET for A. americanum or D. variabilis . In a 7-week time course bioassay, BioUD applied to cotton cheesecloth and held at room temperature provided 5 weeks of > 90% repellency against A. americanum .