Functional Specificity of Sex Pheromone Receptors in the Cotton Bollworm <i>Helicoverpa armigera</i>

<div><p>Male moths can accurately perceive the sex pheromone emitted from conspecific females by their highly accurate and specific olfactory sensory system. Pheromone receptors are of special importance in moth pheromone reception because of their central role in chemosensory signal transduction processes that occur in olfactory receptor neurons in the male antennae. There are a number of pheromone receptor genes have been cloned, however, only a few have been functionally characterized. Here we cloned six full-length pheromone receptor genes from <i>Helicoverpa armigera</i> male antennae. Real-time PCR showing all genes exhibited male-biased expression in adult antennae. Functional analyses of the six pheromone receptor genes were then conducted in the heterologous expression system of <i>Xenopus</i> oocytes. HarmOR13 was found to be a specific receptor for the major sex pheromone component Z11-16:Ald. HarmOR6 was equally tuned to both of Z9-16: Ald and Z9-14: Ald. HarmOR16 was sensitively tuned to Z11-16: OH. HarmOR11, HarmOR14 and HarmOR15 failed to respond to the tested candidate pheromone compounds. Our experiments elucidated the functions of some pheromone receptor genes of <i>H. armigera</i>. These advances may provide remarkable evidence for intraspecific mating choice and speciation extension in moths at molecular level.</p> </div

No ligand was identified of three candidate pheromone receptor genes in <i>H.armigera</i>.

<p>(A) HarmOR11/HarmOR2. (B) HarmOR14/HarmOR2 and (C) HarmOR15/HarmOR2. The concentrations of all tested pheromone compounds were 10⁻⁴ M.</p

Responses of <i>Xenopus</i> oocytes with co-expressed HarmOR6/HarmOR2 to stimulation with pheromone compounds.

<p>(A) Inward current responses of HarmOR6/HarmOR2 <i>Xenopus</i> oocytes in response to 10⁻⁴ M solution of pheromone compounds. (B) Response profile of HarmOR6/HarmOR2 <i>Xenopus</i> oocytes. Error bars indicate SEM (n = 7). (C) HarmOR6/HarmOR2 <i>Xenopus</i> oocytes stimulated with a range of Z9-14:Ald concentrations. (D) Dose–response curve of HarmOR6/HarmOR2 <i>Xenopus</i> oocytes to Z9-14:Ald. Responses are normalized by defining the maximal response as 100. EC50 = 4.338×10⁻⁶ M. Error bars indicate SEM (n = 6). (E) HarmOR6/HarmOR2 <i>Xenopus</i> oocytes stimulated with a range of Z9-16:Ald concentrations. (F) Dose–response curve of HarmOR6/HarmOR2 <i>Xenopus</i> oocytes to Z9-16:Ald. Responses are normalized by defining the maximal response as 100. EC50 = 3.531×10⁻⁶ M. Error bars indicate SEM (n = 6).</p

Phylogenetic tree of the <i>H. armigera</i> PRs and other lepidopterans ORs.

<p>Harm: <i>H. armigera</i> (red), Hvir: <i>H. virescens</i> (blue), Bmor: <i>B. mori</i> (black). The clade of PRs was masked by yellow shadow. The clade of Orco was masked by pink shadow.</p

A Conserved Odorant Receptor Tuned to Floral Volatiles in Three Heliothinae Species

<div><p>Odorant receptors (ORs) play an important role in insects to monitor and adapt to the external environment, such as host plant location, oviposition-site selection, mate recognition and natural enemy avoidance. In our study, we identified and characterized OR12 from three closely-related species, <i>Helicoverpa armigera</i>, <i>Helicoverpa assulta</i>, <i>Heliothis virescens</i>, sharing between 90 and 98% of their amino acids. The tissue expression pattern analysis in <i>H</i>. <i>armigera</i> showed that <i>HarmOR12</i> was strongly expressed both in male and female antennae, but not in other tissues. Functional analysis performed in the heterologous <i>Xenopus</i> expression system showed that all three OR12 were tuned to six structurally related plant volatiles. Electroantennogram recordings from male and female antennae of <i>H</i>. <i>armigera</i> closely matched the data of <i>in vitro</i> functional studies. Our results revealed that OR12 has a conserved role in Heliothinae moths and might represent a suitable target for the control of these crop pests.</p></div

Responses of <i>Xenopus</i> oocytes with co-expressed HarmOR13/HarmOR2 to stimulation with pheromone compounds.

<p>(A) Inward current responses of HarmOR13/HarmOR2 <i>Xenopus</i> oocytes in response to 10⁻⁴ M solution of pheromone compounds. (B) Response profile of HarmOR13/HarmOR2 <i>Xenopus</i> oocytes. Error bars indicate SEM (n = 7). (C) HarmOR13/HarmOR2 <i>Xenopus</i> oocytes stimulated with a range of Z11-16:Ald concentrations. (D) Dose–response curve of HarmOR13/HarmOR2 <i>Xenopus</i> oocytes to Z11-16:Ald. Responses are normalized by defining the maximal response as 100. EC50 = 3.403×10⁻⁶ M. Error bars indicate SEM (n = 6).</p

UV Blocking by Mg–Zn–Al Layered Double Hydroxides for the Protection of Asphalt Road Surfaces

Mg_aZn_bAl_c–CO₃ layered double hydroxides (LDHs) with varying magnesium/zinc ratios have been synthesized by a method involving separate nucleation and aging steps. The resulting LDHs were analyzed by powder X-ray diffraction, laser particle size analysis, scanning electron microscopy, and diffuse reflectance UV spectroscopy. The results show that the UV blocking properties of Mg_aZn_bAl_c–CO₃–LDHs depend on both the proportion of zinc and the particle size distribution. The UV absorbing properties of Mg_aZn_bAl_c–CO₃–LDHs increase with the content of zinc, which can be ascribed to the decrease in the band gap energy, as has been observed experimentally and confirmed by density functional theory calculations. The UV screening properties of Zn₄Al₂–CO₃–LDHs were found to increase with increasing particle size, which can be explained by Mie scattering theory. Moreover, in accelerated UV light irradiation aging tests, LDH-modified asphalt samples showed excellent resistance to UV aging, with the efficacy of the LDH increasing with increasing zinc content

Sequence alignment of OR12 of the three species studied in this work.

<p>Percent of identical amino acids ranges between 90 and 98%. The seven transmebrane domains are marked with black lines.</p

Amino acid sequence alignments of the <i>H. armigera</i> and <i>H. virescens</i> PRs.

<p>Predicted seven-transmembrance domains are identified with roman numbers. Amino acid numbering is given on the right of the alignment. Gaps in the alignment are indicated by a dash.</p

Responses of <i>Xenopus</i> oocytes with co-expressed HarmOR16/HarmOR2 to stimulation with pheromone compounds.

<p>(A) Inward current responses of HarmOR16/HarmOR2 <i>Xenopus</i> oocytes in response to 10⁻⁴ M solution of pheromone compounds. (B) Response profile of HarmOR16/HarmOR2 <i>Xenopus</i> oocytes. Error bars indicate SEM (n = 7). (C) HarmOR16/HarmOR2 <i>Xenopus</i> oocytes stimulated with a range of Z11-16:OH concentrations. (D) Dose–response curve of HarmOR16/HarmOR2 <i>Xenopus</i> oocytes to Z11-16:OH. Responses are normalized by defining the maximal response as 100. EC50 = 2.988×10⁻⁷ M. Error bars indicate SEM (n = 6).</p