The external morphology and distribution of antennal sensilla of Glenea cantor Fabricius were studied with scanning electron microscopy. The antennae of G. cantor were observed to be filiform, consisting of scape, pedicel, and flagellum (nine flagellomeres). Four distinct types of sensory receptors were observed, including sensilla chaetica, sensilla trichodea, sensilla basiconica, and Böhm bristles. Three morphological subtypes of sensilla chaetica were found on the antennae, and sensilla trichodea were also categorized into three morphological subtypes. Sensilla basiconica was grouped into two morphological subtypes that were found on subsegments F2-F9 of the flagellum, and Böhm bristles were only found at the intersegmental joints between the scape and the head and between the scape and the pedicel. The antennae of male and female adults were similar in shape, length, and diameter. However, the length, diameter, distribution, and number of each of the four distinct types of sensilla on the males were significantly different from those on females. The types, lengths, diameters, numbers, and distributions of these sensilla were described, and their possible functions were also discussed. The results indicated that the base and end of an antennal segment have a similar sensillum density, but the middle section sensor density is significantly greater, especially for olfactory and gustatory sensilla, possibly because the joints are more involved in mechanical sensing. The density of sensors is closely related to its sensing function; so, future studies on the biology of olfaction and sexual communication in G. cantor will be facilitated by these observations.

BackgroundChrysomya megacephala (Fabricius) is a prevalent and synanthropic blowfly which has two sides, for being a pathogenic vector, an efficient pollinator, a promising resource of proteins, lipids, chitosan, biofuel et al., and an important forensic indicator. Moreover olfactory proteins are crucial component to function in related processes. However, the genomic platform of C. megacephala remains relatively unavailable. Developmental transcriptomes of eggs, larvae from 1st instar to before pupa stage and adults from emergence to egg laying period were built by RNA-sequencing to establish sequence background of C. megacephala with special lights on olfactory proteins.ResultsClean reads in eggs, larvae and adults were annotated into 59486 transcripts. Transcripts were assembled into 22286, 17180, 18934 and 35900 unigenes in eggs, larvae, adults and the combined datasets, respectively. Unigenes were annotated using Nr (NCBI non-redundant protein sequences), Nt (NCBI non-redundant nucleotide sequences), GO (Gene Ontology), PFAM (Protein family), KOG/COG (Clusters of Orthologous Groups of proteins), Swiss-Prot (A manually annotated and reviewed protein sequence database), and KO (KEGG Orthology). Totally 12196 unigenes were annotated into 51 sub-categories belonging to three main GO categories; 8462 unigenes were classified functionally into 26 categories to KOG classifications; 5160 unigenes were functionally classified into 5 KEGG categories. Moreover, according to RSEM, the number of differentially expressed genes between larvae and eggs, adults and eggs, adults and larvae, and the common differentially expressed genes were 2637, 1804, 2628 and 258, respectively. Among them, 17 odorant-binding proteins (OBPs), 7 chemosensory proteins (CSPs) and 8 ionotropic receptors (IRs) were differently expressed in adults and larvae. Ten were confirmed as significant differentially expressed genes. Furthermore, OBP Cmeg32081-c4 was highly expressed in the female head and Cmeg33593_c0 were up-regulated with the increase of larval age.ConclusionsA comprehensive sequence resource with desirable quality was built by comparative transcriptome of eggs, larvae and adults, enriching the genomic platform of C. megacephala. The identified differentially expressed genes would facilitate the understanding of metamorphosis, development and the fitness to environmental change of C. megacephala. OBP Cmeg32081-c4 and Cmeg33593_c0 might play a crucial role in the interactions between olfactory system and biological processes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-014-1200-y) contains supplementary material, which is available to authorized users.

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P-element-induced wimpy-like (Piwil) proteins restrict the replication of mobile genetic elements in the germ line. They are also expressed in many transformed cell lines. In this study, we discovered that the human Piwil 2 (Hili) protein can also inhibit HIV replication, especially in activated CD4+ T cells that are the preferred target cells for this virus in the infected host. Although resting cells did not express Hili, its expression was rapidly induced following T cell activation. In these cells and transformed cell lines, depletion of Hili increased levels of viral proteins and new viral particles. Further studies revealed that Hili binds to tRNA. Some of the tRNAs represent rare tRNA species, whose codons are overrepresented in the viral genome. Targeting tRNAArg(UCU) with an antisense oligonucleotide replicated effects of Hili and also inhibited HIV replication. Finally, Hili also inhibited the retrotransposition of the endogenous intracysternal A particle (IAP) by a similar mechanism. Thus, Hili joins a list of host proteins that inhibit the replication of HIV and other mobile genetic elements. IMPORTANCE Piwil proteins inhibit the movement of mobile genetic elements in the germ line. In their absence, sperm does not form and male mice are sterile. This inhibition is thought to occur via small Piwi-interacting RNAs (piRNAs). However, in some species and in human somatic cells, Piwil proteins bind primarily to tRNA. In this report, we demonstrate that human Piwil proteins, especially Hili, not only bind to select tRNA species, including rare tRNAs, but also inhibit HIV replication. Importantly, T cell activation induces the expression of Hili in CD4+ T cells. Since Hili also inhibited the movement of an endogenous retrovirus (IAP), our finding shed new light on this intracellular resistance to exogenous and endogenous retroviruses as well as other mobile genetic elements.