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Insect Biochemistry and Molecular Biology

Yan Li, Jie Zhang, Dafeng Chen, Pengcheng Yang, Feng Jiang, Xianhui Wang, Le Kang
Locusts are important agricultural pests worldwide and regarded as study models for entomology. However, the absence of targeted gene manipulation systems for locusts has restricted their applications for research. Herein, we report the successful use of the CRISPR/Cas9 system to induce a targeted heritable mutagenesis of the migratory locust, Locusta migratoria. The target sequence of gRNA was designed to disrupt the gene encoding the odorant receptor co-receptor (Orco) and examine the roles of the odorant receptor pathway in the locust...
October 12, 2016: Insect Biochemistry and Molecular Biology
Paolo Gabrieli, Francesca Scolari, Alessandro Di Cosimo, Grazia Savini, Marco Fumagalli, Ludvik M Gomulski, Anna R Malacrida, Giuliano Gasperi
In the Mediterranean fruit fly, Ceratitis capitata (Wiedemann)(Diptera: Tephritidae), mating has a strong impact on female biology, leading to a decrease in sexual receptivity and increased oviposition and fecundity. Previous studies suggest that sperm transfer may play a role in inducing these behavioural changes. Here we report the identification of a medfly innexin gene, Cc-inx5, whose expression is limited to the germ-line of both sexes. Through RNA interference of this gene, we generated males without testes and, consequently, sperm, but apparently retaining all the other reproductive organs intact...
October 6, 2016: Insect Biochemistry and Molecular Biology
Denyse Cavalcante Lago, Fernanda Carvalho Humann, Angel Roberto Barchuk, Kuruvilla Joseph Abraham, Klaus Hartfelder
Adult honey bee queens and workers drastically differ in ovary size. This adult ovary phenotype difference becomes established during the final larval instar, when massive programmed cell death leads to the degeneration of 95-99% of the ovariole anlagen in workers. The higher juvenile hormone (JH) levels in queen larvae protect the ovaries against such degeneration. To gain insights into the molecular architecture underlying this divergence critical for adult caste fate and worker sterility, we performed a microarray analysis on fourth and early fifth instar queen and worker ovaries...
October 5, 2016: Insect Biochemistry and Molecular Biology
Immacolata Iovinella, Liping Ban, Limei Song, Paolo Pelosi, Francesca Romana Dani
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...
September 29, 2016: Insect Biochemistry and Molecular Biology
Corinna Krempl, Hanna M Heidel-Fischer, Guillermo Hugo Jiménez-Alemán, Michael Reichelt, Riya Christina Menezes, Wilhelm Boland, Heiko Vogel, David G Heckel, Nicole Joußen
Gossypol is a polyphenolic secondary metabolite produced by cotton plants, which is toxic to many organisms. Gossypol's aldehyde groups are especially reactive, forming Schiff bases with amino acids of proteins and cross-linking them, inhibiting enzyme activities and contributing to toxicity. Very little is known about gossypol's mode of action and its detoxification in cotton-feeding insects that can tolerate certain concentrations of this compound. Here, we tested the toxicity of gossypol and a gossypol derivative lacking free aldehyde groups (SB-gossypol) toward Helicoverpa armigera and Heliothis virescens, two important pests on cotton plants...
September 26, 2016: Insect Biochemistry and Molecular Biology
June-Sun Yoon, Jayendra Nath Shukla, Zhong Jun Gong, Kanakachari Mogilicherla, Subba Reddy Palli
RNA interference (RNAi) is a useful reverse genetics tool for investigation of gene function as well as for practical applications in many fields including medicine and agriculture. RNAi works very well in coleopteran insects including the Colorado potato beetle (CPB), Leptinotarsa decemlineata. We used a cell line (Lepd-SL1) developed from CPB to identify genes that play key roles in RNAi. We screened 50 genes with potential functions in RNAi by exposing Lepd-SL1 cells to dsRNA targeting one of the potential RNAi pathway genes followed by incubation with dsRNA targeting inhibitor of apoptosis (IAP, silencing of this gene induces apoptosis)...
September 26, 2016: Insect Biochemistry and Molecular Biology
Cristina Yunta, Nelson Grisales, Szilárd Nász, Kay Hemmings, Patricia Pignatelli, Michael Voice, Hilary Ranson, Mark J I Paine
Pyrethroid resistance is widespread in the malaria vector Anopheles gambiae leading to concerns about the future efficacy of bednets with pyrethroids as the sole active ingredient. The incorporation of pyriproxyfen (PPF), a juvenile hormone analogue, into pyrethroid treated bednets is being trialed in Africa. Pyrethroid resistance is commonly associated with elevated levels of P450 expression including CYPs 6M2, 6P2, 6P3, 6P4, 6P5, 6Z2 and 9J5. Having expressed these P450s in E. coli we find all are capable of metabolizing PPF...
September 7, 2016: Insect Biochemistry and Molecular Biology
Jian Pu, Haina Sun, Jinda Wang, Min Wu, Kangxu Wang, Ian Denholm, Zhaojun Han
As well as arising from single point mutations in binding sites or detoxifying enzymes, it is likely that insecticide resistance mechanisms are frequently controlled by multiple genetic factors, resulting in resistance being inherited as a quantitative trait. However, empirical evidence for this is still rare. Here we analyse the causes of up-regulation of CYP6FU1, a monoxygenase implicated in resistance to deltamethrin in the rice pest Laodelphax striatellus. The 5'-flanking region of this gene was cloned and sequenced from individuals of a susceptible and a resistant strain...
August 31, 2016: Insect Biochemistry and Molecular Biology
Hartmut Kayser, Manfred Nimtz
Bilins, derived from biliverdin IXα, are known from animals, plants and microorganisms, where they play vital roles as light-absorbing pigments. Bilins occur also in many insects. Recently, we discovered in insects a novel structural type of bilins with a farnesyl substituent at pyrrole ring A of biliverdin IXα. The first of these unusual bilins with a molecular mass of 852 (C48H60O10N4) was identified in Cerura vinula, subsequently in Spodoptera littoralis; both species are members of the Noctuoidea superfamily of moths...
August 28, 2016: Insect Biochemistry and Molecular Biology
Yoko Takasu, Isao Kobayashi, Toshiki Tamura, Keiro Uchino, Hideki Sezutsu, Michal Zurovec
Engineered nucleases are able to introduce double stranded breaks at desired genomic locations. The breaks can be repaired by an error-prone non-homologous end joining (NHEJ) mechanism, or the repair process can be exploited to introduce precise DNA modifications by homology-directed repair (HDR) when provided with a suitable donor template. We designed a series of DNA donors including long dsDNA plasmids as well as short ssDNA oligonucleotides and compared the effectiveness of their utilization during gene targeting with highly efficient transcription activator-like effector nucleases (TALENs)...
August 25, 2016: Insect Biochemistry and Molecular Biology
Jaroslav Srp, Martina Nussbaumerová, Martin Horn, Michael Mareš
The Colorado potato beetle (CPB), Leptinotarsa decemlineata, is a major pest of potato plants, and its digestive system is a promising target for development of pest control strategies. This work focuses on functional proteomic analysis of the digestive proteolytic enzymes expressed in the CPB gut. We identified a set of peptidases using imaging with specific activity-based probes and activity profiling with selective substrates and inhibitors. The secreted luminal peptidases were classified as: (i) endopeptidases of cathepsin D, cathepsin L, and trypsin types and (ii) exopeptidases with aminopeptidase (cathepsin H), carboxypeptidase (serine carboxypeptidase, prolyl carboxypeptidase), and carboxydipeptidase (cathepsin B) activities...
August 15, 2016: Insect Biochemistry and Molecular Biology
G Andreas Boeckler, Christian Paetz, Peter Feibicke, Jonathan Gershenzon, Sybille B Unsicker
The survival of insect herbivores on chemically defended plants may often depend on their ability to metabolize these defense compounds. However, only little knowledge is available on how insects actually process most plant defense compounds. We investigated the metabolism of salicinoids, a major group of phenolic glycosides in poplar and willow species, by a generalist herbivore, the gypsy moth (Lymantria dispar). Seven salicinoid metabolites identified in gypsy moth caterpillar feces were mostly conjugates with glucose, cysteine or glycine...
August 5, 2016: Insect Biochemistry and Molecular Biology
Toshinori Fuse, Tomo Kita, Yunosuke Nakata, Fumiyo Ozoe, Yoshihisa Ozoe
Ivermectin (IVM) is a macrocyclic lactone that exerts antifilarial, antiparasitic, and insecticidal effects on nematodes and insects by acting on l-glutamic acid-gated chloride channels (GluCls). IVM also acts as an allosteric modulator of various other ion channels. Although the IVM binding site in the Caenorhabditis elegans GluCl was identified by X-ray crystallographic analysis, the mechanism of action of IVM in insects is not well defined. We therefore examined the action of IVM on the housefly (Musca domestica) GluCl and γ-aminobutyric acid (GABA)-gated ion channel (GABACl)...
October 2016: Insect Biochemistry and Molecular Biology
Bo Zhao, Yuan Hou, Jianjun Wang, Vladimir A Kokoza, Tusar T Saha, Xue-Li Wang, Ling Lin, Zhen Zou, Alexander S Raikhel
In anautogenous mosquitoes, juvenile hormone III (JH) plays an essential role in female post-eclosion (PE) development, preparing them for subsequent blood feeding and egg growth. We re-examined the JH titer during the reproductive cycle of female Aedes aegypti mosquitoes. Using liquid chromatography coupled with triple tandem mass spectrometry (LC-MS/MS/MS), we have shown that it reaches its peak at 48-54 h PE in the female hemolymph and at 72 h PE in whole body extracts. This method represents an effective assay for determination of JH titers...
October 2016: Insect Biochemistry and Molecular Biology
Ji-Feng Shi, Qing-Yu Xu, Qiang-Kun Sun, Qing-Wei Meng, Li-Li Mu, Wen-Chao Guo, Guo-Qing Li
Trehalose is proposed to serve multiple physiological roles in insects. However, its importance remains largely unconfirmed. In the present paper, we knocked down either a trehalose biosynthesis gene (trehalose-6-phosphate synthase, LdTPS) or each of three degradation genes (soluble trehalases LdTRE1a, LdTRE1b or membrane-bound LdTRE2) in Leptinotarsa decemlineata by RNA interference (RNAi). Knockdown of LdTPS decreased trehalose content and caused larval and pupal lethality. The LdTPS RNAi survivors consumed a greater amount of foliage, obtained a heavier body mass, accumulated more glycogen, lipid and proline, and had a smaller amount of chitin compared with the controls...
October 2016: Insect Biochemistry and Molecular Biology
Gaoqun Zhang, Yangguang Hao, Li Hua Jin
Melanotic nodules are commonly assumed to be caused by an abnormal immune response. Several hematopoietic mutants and signaling pathways, including the Toll, JAK/STAT, Ras and JNK pathways, can cause melanotic nodules to develop when specifically activated in hemocytes. Here, we used the UAS-Gal4 system to overexpress jumeaux (jumu) in the fly immune response system. Jumeaux (Jumu) is a new member of the winged-helix/forkhead (WH/FKH) gene family of transcription factors, which plays an important role in the growth and morphogenesis of Drosophila and participates in the proliferation and differentiation of hemocytes...
October 2016: Insect Biochemistry and Molecular Biology
Evelien Van Ekert, François Chauvigné, Roderick Nigel Finn, Lolita G Mathew, J Joe Hull, Joan Cerdà, Jeffrey A Fabrick
The Middle East-Asia Minor 1 (MEAM1) whitefly, Bemisia tabaci (Gennadius) is an economically important pest of food, fiber, and ornamental crops. This pest has evolved a number of adaptations to overcome physiological challenges, including 1) the ability to regulate osmotic stress between gut lumen and hemolymph after imbibing large quantities of a low nitrogen, sugar-rich liquid diet; 2) the ability to avoid or prevent dehydration and desiccation, particularly during egg hatching and molting; and 3) to be adapted for survival at elevated temperatures...
October 2016: Insect Biochemistry and Molecular Biology
Rafaela M M Paim, Ricardo N Araujo, Miguel Leis, Mauricio R V Sant'anna, Nelder F Gontijo, Claudio R Lazzari, Marcos H Pereira
Blood-sucking vectors must overcome thermal stress caused by intake of proportionally large amounts of warm blood from their hosts. In response to this, Heat Shock Proteins (HSPs) such as the widely studied HSP70 family (the inducible HSP70 and the cognate form HSC70, known for their role in preserving essential cellular functions) are rapidly up-regulated in their tissues. The triatomine Rhodnius prolixus is an important vector of Trypanosoma cruzi, the causative pathogen of Chagas' disease, and is also a model organism for studying insect biology and physiology...
October 2016: Insect Biochemistry and Molecular Biology
Sneha Yogindran, Manchikatla Venkat Rajam
The insect pests are real threat to farmers as they affect the crop yield to a great extent. The use of chemical pesticides for insect pest control has always been a matter of concern as they pollute the environment and are also harmful for human health. Bt (Bacillus thuringensis) technology helped the farmers to get rid of the insect pests, but experienced a major drawback due to the evolution of insects gaining resistance towards these toxins. Hence, alternative strategies are high on demand to control insect pests...
October 2016: Insect Biochemistry and Molecular Biology
Kangxu Wang, Yingchuan Peng, Jian Pu, Wenxi Fu, Jiale Wang, Zhaojun Han
RNA interference (RNAi) has become an essential technique in entomology research. However, RNAi efficiency appears to vary significantly among insect species. Here, the sensitivity of four insect species from different orders to RNAi was compared to understand the reason for this variation. A previously reported method was modified to monitor trace amounts of double-stranded RNA (dsRNA). After the administration of dsRNA, the dynamics of its content was determined in the hemolymph, in addition to the capability of its degradation in both the hemolymph and the midgut juice...
October 2016: Insect Biochemistry and Molecular Biology
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