Sex pheromones and olfactory proteins in Antheraea moths: A. pernyi and A. polyphemus (Lepidoptera: Saturniidae)

Olfaction is essential for regulating the physiological and behavioral actions of insects with specific recognition of various odors. Antheraea moths (Lepidoptera: Saturniidae) possess relatively large bodies and antennae so that they are good subjects for exploring molecular aspects of insect olfaction. Current knowledge of the molecular aspects of Antheraea olfaction is focused on the Chinese tussah silkmoth A. pernyi Guérin-Méneville and another species A. polyphemus (Cramer) in their pheromones, odorant-binding proteins (OBPs), odorant receptors (ORs), odorant receptor coreceptors (ORCOs), sensory neuron membrane proteins (SNMPs), and odorant-degrading enzymes (ODEs). The first insect OBP, SNMP, and ODE were identified from A. polyphemus. This review summarizes the principal findings associated with the olfactory physiology and its molecular components in the two Antheraea species. Three types of olfactory neurons may have specific ORs for three respective sex-pheromone components, with the functional sensitivity and specificity mediated by three respective OBPs. SNMPs and ODEs are likely to play important roles in sex-pheromone detection, inactivation, and degradation. Identification and functional analysis of the olfactory molecules remain to be further performed in A. pernyi, A. polyphemus, and other Antheraea species.     

Proteomic analysis of castor bean tick Ixodes ricinus: a focus on chemosensory organs

In arthropods, the large majority of studies on olfaction have been focused on insects, where most of the proteins involved have been identified. In particular, chemosensing in insects relies on two families of membrane receptors, olfactory/gustatory receptors (ORs/GRs) and ionotropic receptors (IRs), and two classes of soluble proteins, odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). In other arthropods, such as ticks and mites, only IRs have been identified, while genes encoding for OBPs and CSPs are absent. A third class of soluble proteins, called Niemann-Pick C2 (NPC2) has been suggested as potential carrier for semiochemicals both in insects and other arthropods.Here we report the results of a proteomic analysis on olfactory organs (Haller's organ and palps) and control tissues of the tick Ixodes ricinus, and of immunostaining experiments targeting NPC2s. Adopting different extraction and proteomic approaches, we identified a large number of proteins, and highlighted those differentially expressed. None of the 13 NPC2s known for this species was found. On the other hand, using immunocytochemistry, we detected reaction against one NPC2 in the Haller's organ and palp sensilla. We hypothesized that the low concentration of such proteins in the tick's tissues could possibly explain the discrepant results. In ligand-binding assays the corresponding recombinant NPC2 showed good affinity to the fluorescent probe N-phenylnaphthylamine and to few organic compounds, supporting a putative role of NPC2s as odorant carriers.     

锤胁跷蝽触角转录组分析

为了获得锤胁跷蝽(Yemma signatus Hsiao)触角基因信息,本研究使用Illumina HiSeq TM 4 000高通量测序技术对锤胁跷蝽成虫触角进行转录组测序和生物学信息分析。共获得61 080 938条clean reads,包括9.16 G (GenBank登录号:SRR3348966)。拼接115 491条unigenes,平均长度为578 bp,N50为863 bp。在7大数据库中注释到46 224条unigenes,其中在NR数据库中注释的基因最多,为32 842 (28.43%)条,与内华达古白蚁(Zootermopsis nevadensis)相似度最高(9.0%)。转录组数据分析鉴定出125个与嗅觉相关的基因,其中66个嗅觉受体、11个味觉受体、1个离子型受体、3个感觉神经元膜蛋白、30个气味结合蛋白和14个化学感受蛋白基因。本研究首次获得锤胁跷蝽触角转录组数据,并鉴定出嗅觉相关基因,本研究为今后利用嗅觉基因靶标防治害虫提供了分子生物学信息数据。