Functional map of the macroglomerular complex of male Helicoverpaarmigera

The mechanism of sex pheromone reception in the male cotton bollworm Helicoverpa armigera has been extensively studied because it has become an important model system for understanding insect olfaction.However,the pathways of pheromone processing from the antenna to the primary olfactory center in H.armigera have not yet been clarified.Here,the physiology and morphology of male H.armigera olfactory sensory neurons(OSNs)were studied using single sensillum recording along with anterograde filling and intracellular recording with retrograde filling.OSNs localized in type A sensilla responded to the major pheromone component cis-11-hexadecenal,and the axonal terminals projected to the cumulus(Cu)of the macroglomerular complex(MGC).The OSNs in type B sensilla respondcd to the bchavioral antagonist cis-9-tetradecenal,and the axonal terminals projected to the dorsomedial anterior(DMA)unit of the MGC.In type C sensilla,there were 2 OSNs:one that responded to cis-9-tetradecenal and cis-11-hexadecenol with the axonal terminals projecting to the DMA,and another that responded to the secondary pheromone components cis-9-hexadecenal and cis-9-tetradecenal with the axonal terminals projecting to the dorsomedial posterior(DMP)unit of the MGC.Type A and type B sensilla also housed the secondary OSNs,which were silent neurons with axonal terminals projected to the glomerulus G49 and DMP.Overall,the neural pathways that carry information on attractiveness and aversiveness in response to female pheromone components in H.armigera exhibit distinct projections to the MGC units.

Expression and immunocytochemical analysis of Autographa californica nucleopolyhedrovirus （AcMNPV） orf74 gene

Autographa californica nucleopolyhedrovirus off74 （Ac74） is located between 62 311 and 63 108bp in the AcMNPV genome, which encodes 265 amino acid residues with a predicted 31 kDa molecular weight. The homologues of Ac74 were searched using BLASTP in protein databases, GenBank/EMBL and SWISS-PROT. The result revealed that deduced Ac74 protein was homologous to the predicted products from 10 lepidoptera NPV ORFs. The multiple sequence alignments of Ac74 and its 10 homologues manifested only one amino acid residue was completely conserved. The transcript analysis revealed that the transcript of Ac74 was detected from 24-72 hours post-infection （hpi）. The product of Ac74 was detected at 24 hpi and lasted until 72 hpi by Western blot using anti-Ac74 antiserum, consistent with reverse transcriptase polymerase chain reaction results. These results suggested Ac74 was expressed during the later stages of infection. The product of Ac74 was 31kDa in size, consistent with predicted molecular weight. The subcellular localization of Ac74 proteins manifested Ac74 protein in the cytoplasm, and was hardly present in the nucleus at 24 hpi. The fluorescence was also observed in polyhedra, except cytoplasm at 72 hpi. Together, Ac74 is a functional protein with 31kDa molecular weight and is located in the cytoplasm and the polyhedra.

Transcriptional analysis of sex pheromone biosynthesis signal genes in Bombyx mori

Six sex pheromone synthesis signal genes, including aeyl coenzyme A （acyl- CoA） desaturase （desatl）, fatty acyl reduetase （FAR）, pheromone biosynthesis activating neuropeptide receptor （PBANR）, fatty acid transport protein （FATP）, acyl-CoA binding protein （ACBP） and store-operated channel protein （OrailA）, were studied for their tran- scriptional regulations. The expression profiles of these transcripts at different develop- mental stages （from -96 to 48 h） revealed that the genes are expressed in an age-dependent manner. The transcripts of these genes continued to increase despite decapitation, and compared with normally developmental females, decapitation significantly inhibited their expression. Further experiments with a methoprene, a juvenile hormone （JH） analogue, challenge showed that JH was not a key inhibiting factor in the expression of these genes, and mating was found to significantly inhibit the expression of these marker genes. Alto- gether, the results provide a reference for understanding the mechanism of sex pheromone synthesis.

Molecular identification of a pancreatic lipase-like gene involved in sex pheromone biosynthesis of Bombyx mori

Cytoplasmic lipid droplet （LD） lipolysis is regulated by pheromone biosynthe- sis activating neuropeptide （PBAN） in Bombyx mori. To elucidate the molecular mechanism of cytoplasm LD lipolysis, the pancreatic lipase-like gene in B. mori pheromone glands （PGs）, designated as B. mori pancreatic lipase-like gene （BmPLLG）, was identified in this study. Spatial expression analysis revealed that BmPLLG is a ubiquitous gene present in all studied tissues, such as PGs, brain, epidermis, egg, midgut, flight muscle and fat body. Temporal expression analysis showed that the BmPLLG transcript begins to express 96 h before eclosion （-96 h）, continues to increase, peaks in newly emerged females and steadily decreases after eclosion. Translational expression analysis of BmPLLG using a prepared antiserum demonstrated that BmPLLG was expressed in an age-dependent pat- tern at different development stages in B. mori. This finding was similar to the transcript expression pattern. Further RNA interference-mediated knockdown of BmPLLG signifi- cantly inhibited bombykol production. Overall, these results demonstrated that BmPLLG is involved in PBAN-induced sex pheromone biosynthesis and release.