P r e f a c e
PREFACE TO THE SPECIAL ISSUES
This Special Issue is the second of two issues drawn from articles originally delivered at the Fourth International Symposium on Insect Physiology, Biochemistry and Molecular Biology, convened in Nanjing, China during June, 2013. The two special issues present 10 articles, five in each issue. The International Symposium Series is growing in international recognition. The symposium in Nanjing attracted over 300 attendees from China, the United States, United Kingdom, Germany, Japan, Thailand, Iran, and other countries. The articles in this issue are selected to highlight advances in insect science. In the following paragraphs, we introduce each of the five articles in this issue. Olfaction is very sensitive and important in insect biology. Odorant compounds make their ways into sensillar pores, then bind to odorant binding proteins. These proteins transport the compounds through hydrophilic sensillar lymph and onto odorant receptors. Interactions with the receptors lead to electrical signaling to the CNS, where the signals are integrated. The odorant compounds are rapidly hydrolyzed by odorant-degrading enzymes. Airborne odorants can become sources of olfactory background noise, which can confound signaling between insects and their environment. Dr. He and his group contribute new information by cloning six genes encoding odorant-degrading enzymes from Spodoptera exigua. The genes are mostly expressed in antennae, however, two of them, SexiCXE5 and SexiCSE18, are mainly expressed in the wings. The authors expressed SexiCXE4 in High-Five cells to investigate the protein in more detail. They report that the purified enzyme has a marked preference for plant volatiles over sex pheromone and suggest this enzyme functions in degradation of plant volatiles. Trehalose is the major hemolymph sugar in most insect species. The disaccharide is hydrolyzed to two glucose molecules by trehalase. Two forms are recognized, a soluble and a membrane-bound form. Tan et al. cloned both forms from the cotton mired bug, Apolygus lucorum. Enzyme assays demonstrate that the soluble form is responsible for most trehalase activity in juveniles and in six separate tissues in adult females. qPCR analysis shows both forms are expressed at approximately the same levels in juveniles and adults, while the soluble form is very highly expressed in ovaries and Malpighian tubules. The authors found that ecdysteriod treatments increased enzyme activity and gene expression for the soluble, but not the membrane-bound form of the enzyme. Hence, the soluble trahalase is a developmentally regulated enzyme. Selecting oviposition substrates is a crucial moment in insect lives because small larvae are not able to move to alternative, perhaps more preferable, plants. Some plants deter egg laying by potentially harmful insect species via chemical signals. Dr. GuoHua Zhong and ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY, Vol. 86, No. 2, 73–74 (2014) Published online in Wiley Online Library (wileyonlinelibrary.com). C 2014 Wiley Periodicals, Inc. DOI: 10.1002/arch.21172
74
r
Archives of Insect Biochemistry and Physiology, June 2014
his group considered the mechanism of oviposition deterrence in the Oriental leafworm, Spodoptera litura. Rhodojaponin-III is a diterpene isolated from Rhododendron molle G. don flowers; the compound exerts contact toxicity against test insects. The authors report that this compound deterred oviposition by gravid females. They found that sealing the antennae of experimental insects did not reduce egg laying behavior. Digging a bit deeper, they conducted EAG recordings, which showed that Rhodojanonin-III elicited only 2–3% of the responses generated by leaf alcohol. They finally found that only physical contact with Rhodojaponin-III deterred oviposition activity, from which they inferred that sensilla located on the tarsus and ovipositor are responsible for the deterring influence of the compound. Amino acid deficiency exerts serious negative effects on the growth, maintenance, and reproduction of most animals, including insects. Dr. Zhou and co-workers developed the hypothesis that amino acid deficiency leads to a physiological trade-off between survival and reproduction in the brown planthopper, Nilaparvata lugens. Rearing larvae on an amino acid deficient artificial medium led to abbreviated larval periods and increased proportions of adults with malformed wings, but did not influence eclosion. The deficient diets also led to catastrophic reductions in oviposition and to reduced female life spans. On the other hand, the influence of amino acid deficiency did not extend to differences in lipid and protein stores in adults. The authors interpreted their findings with respect to a physiological trade-off between survival and reproduction. The dopamine monoxygenase N-terminal (DOMON) domain occurs in extracellular proteins, including the Knickkopf protein of Drosophila. Knickkopf co-localizes with newly synthesized cuticle and serves to protect the new cuticle from chitinases that degrade the old cuticle. Moussian and his colleagues investigated the role of the DOMON domain in Knickkopf by creating Knickkopf versions with unusual amino acid residues in positions of tryptophan299 , methionine333 , arginine401 and histidine437 . They report the absolute necessity of in tryptophan299 , methionine333 , and histidine437 for Knickkopf function and stability. Arginine401 is necessary to achieve complete functional efficiency of the protein. This work demonstrates that the DOMON domain is essential for construction of the chitin component of new cuticles. The work has broad significance because Knickkopf is a conserved protein across insects, crustaceans, and nematodes and, aside from protecting newly formed cuticle, it is crucial to creating the laminar structures of exoskeleton chitin. We hope the articles in both of the Special Issues are of interest to a wide readership. The Fifth International Symposium on Insect Physiology, Biochemistry, and Molecular Biology will convene during the summer, 2015 in Guangzhou, China. We look forward to seeing you there. Guest Editors: Fei Li Department of Entomology, Nanjing Agricultural University, Nanjing, China Gong-yin Ye Institute of Insect Science, Zhejiang University, Hangzhou, China Qisheng Song Division of Plant Sciences, University of Missouri, Columbia, MO, USA
Archives of Insect Biochemistry and Physiology
PREFACE TO THE SPECIAL ISSUES
This Special Issue is the second of two issues drawn from articles originally delivered at the Fourth International Symposium on Insect Physiology, Biochemistry and Molecular Biology, convened in Nanjing, China during June, 2013. The two special issues present 10 articles, five in each issue. The International Symposium Series is growing in international recognition. The symposium in Nanjing attracted over 300 attendees from China, the United States, United Kingdom, Germany, Japan, Thailand, Iran, and other countries. The articles in this issue are selected to highlight advances in insect science. In the following paragraphs, we introduce each of the five articles in this issue. Olfaction is very sensitive and important in insect biology. Odorant compounds make their ways into sensillar pores, then bind to odorant binding proteins. These proteins transport the compounds through hydrophilic sensillar lymph and onto odorant receptors. Interactions with the receptors lead to electrical signaling to the CNS, where the signals are integrated. The odorant compounds are rapidly hydrolyzed by odorant-degrading enzymes. Airborne odorants can become sources of olfactory background noise, which can confound signaling between insects and their environment. Dr. He and his group contribute new information by cloning six genes encoding odorant-degrading enzymes from Spodoptera exigua. The genes are mostly expressed in antennae, however, two of them, SexiCXE5 and SexiCSE18, are mainly expressed in the wings. The authors expressed SexiCXE4 in High-Five cells to investigate the protein in more detail. They report that the purified enzyme has a marked preference for plant volatiles over sex pheromone and suggest this enzyme functions in degradation of plant volatiles. Trehalose is the major hemolymph sugar in most insect species. The disaccharide is hydrolyzed to two glucose molecules by trehalase. Two forms are recognized, a soluble and a membrane-bound form. Tan et al. cloned both forms from the cotton mired bug, Apolygus lucorum. Enzyme assays demonstrate that the soluble form is responsible for most trehalase activity in juveniles and in six separate tissues in adult females. qPCR analysis shows both forms are expressed at approximately the same levels in juveniles and adults, while the soluble form is very highly expressed in ovaries and Malpighian tubules. The authors found that ecdysteriod treatments increased enzyme activity and gene expression for the soluble, but not the membrane-bound form of the enzyme. Hence, the soluble trahalase is a developmentally regulated enzyme. Selecting oviposition substrates is a crucial moment in insect lives because small larvae are not able to move to alternative, perhaps more preferable, plants. Some plants deter egg laying by potentially harmful insect species via chemical signals. Dr. GuoHua Zhong and ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY, Vol. 86, No. 2, 73–74 (2014) Published online in Wiley Online Library (wileyonlinelibrary.com). C 2014 Wiley Periodicals, Inc. DOI: 10.1002/arch.21172
74
r
Archives of Insect Biochemistry and Physiology, June 2014
his group considered the mechanism of oviposition deterrence in the Oriental leafworm, Spodoptera litura. Rhodojaponin-III is a diterpene isolated from Rhododendron molle G. don flowers; the compound exerts contact toxicity against test insects. The authors report that this compound deterred oviposition by gravid females. They found that sealing the antennae of experimental insects did not reduce egg laying behavior. Digging a bit deeper, they conducted EAG recordings, which showed that Rhodojanonin-III elicited only 2–3% of the responses generated by leaf alcohol. They finally found that only physical contact with Rhodojaponin-III deterred oviposition activity, from which they inferred that sensilla located on the tarsus and ovipositor are responsible for the deterring influence of the compound. Amino acid deficiency exerts serious negative effects on the growth, maintenance, and reproduction of most animals, including insects. Dr. Zhou and co-workers developed the hypothesis that amino acid deficiency leads to a physiological trade-off between survival and reproduction in the brown planthopper, Nilaparvata lugens. Rearing larvae on an amino acid deficient artificial medium led to abbreviated larval periods and increased proportions of adults with malformed wings, but did not influence eclosion. The deficient diets also led to catastrophic reductions in oviposition and to reduced female life spans. On the other hand, the influence of amino acid deficiency did not extend to differences in lipid and protein stores in adults. The authors interpreted their findings with respect to a physiological trade-off between survival and reproduction. The dopamine monoxygenase N-terminal (DOMON) domain occurs in extracellular proteins, including the Knickkopf protein of Drosophila. Knickkopf co-localizes with newly synthesized cuticle and serves to protect the new cuticle from chitinases that degrade the old cuticle. Moussian and his colleagues investigated the role of the DOMON domain in Knickkopf by creating Knickkopf versions with unusual amino acid residues in positions of tryptophan299 , methionine333 , arginine401 and histidine437 . They report the absolute necessity of in tryptophan299 , methionine333 , and histidine437 for Knickkopf function and stability. Arginine401 is necessary to achieve complete functional efficiency of the protein. This work demonstrates that the DOMON domain is essential for construction of the chitin component of new cuticles. The work has broad significance because Knickkopf is a conserved protein across insects, crustaceans, and nematodes and, aside from protecting newly formed cuticle, it is crucial to creating the laminar structures of exoskeleton chitin. We hope the articles in both of the Special Issues are of interest to a wide readership. The Fifth International Symposium on Insect Physiology, Biochemistry, and Molecular Biology will convene during the summer, 2015 in Guangzhou, China. We look forward to seeing you there. Guest Editors: Fei Li Department of Entomology, Nanjing Agricultural University, Nanjing, China Gong-yin Ye Institute of Insect Science, Zhejiang University, Hangzhou, China Qisheng Song Division of Plant Sciences, University of Missouri, Columbia, MO, USA
Archives of Insect Biochemistry and Physiology
