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Zhou Z, Yao Z, Abouzaid M, Hull JJ, Ma W, Hua H, Lin Y. Co-Expression Network Analysis: A Future Approach for Pest Control Target Discovery. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:7201-7209. [PMID: 37146201 DOI: 10.1021/acs.jafc.3c00113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The striped stem borer (SSB, Chilo suppressalis Walker) is a major pest of rice worldwide. Double-stranded RNAs (dsRNAs) targeting essential genes can trigger a lethal RNA interference (RNAi) response in insect pests. In this study, we applied a Weighted Gene Co-expression Network Analysis (WGCNA) to diet-based RNA-Seq data as a method to facilitate the discovery of novel target genes for pest control. Nieman-Pick type c 1 homolog b (NPC1b) was identified as the gene with the highest correlation values to hemolymph cholesterol levels and larval size. Functional characterization of the gene supported CsNPC1b expression with dietary cholesterol uptake and insect growth. This study revealed the critical role of NPC1b for intestinal cholesterol absorption in lepidopteran insects and highlights the utility of the WGCNA approach for identifying new pest management targets.
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Affiliation(s)
- Zaihui Zhou
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhuotian Yao
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Mostafa Abouzaid
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - J Joe Hull
- Pest Management and Biocontrol Research Unit, US Arid Land Agricultural Research Center, USDA Agricultural Research Services, Maricopa, Arizona 85138, United States
| | - Weihua Ma
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hongxia Hua
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yongjun Lin
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Entringer PF, Majerowicz D, Gondim KC. The Fate of Dietary Cholesterol in the Kissing Bug Rhodnius prolixus. Front Physiol 2021; 12:654565. [PMID: 33868022 PMCID: PMC8047208 DOI: 10.3389/fphys.2021.654565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 02/23/2021] [Indexed: 11/13/2022] Open
Abstract
Insects are unable to synthesize cholesterol and depend on the presence of sterols in the diet for cell membrane composition and hormone production. Thus, cholesterol absorption, transport, and metabolism are potential targets for vector and pest control strategies. Here, we investigate the dietary cholesterol absorption and tissue distribution in the kissing bug Rhodnius prolixus using radiolabeled cholesterol. Both the anterior and posterior midguts absorbed cholesterol from the ingested blood, although the anterior midgut absorbed more. We also observed esterified cholesterol labeling in the epithelium, indicating that midgut cells can metabolize and store cholesterol. Only a small amount of labeled cholesterol was found in the hemolymph, where it was mainly in the free form and associated with lipophorin (Lp). The fat body transiently accumulated cholesterol, showing a labeled cholesterol peak on the fifth day after the blood meal. The ovaries also incorporated cholesterol, but cumulatively. The insects did not absorb almost half of the ingested labeled cholesterol, and radioactivity was present in the feces. After injection of 3H-cholesterol-labeled Lp into females, a half-life of 5.5 ± 0.7 h in the hemolymph was determined. Both the fat body and ovaries incorporated Lp-associated cholesterol, which was inhibited at low temperature, indicating the participation of active cholesterol transport. These results help describe an unexplored part of R. prolixus lipid metabolism.
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Affiliation(s)
- Petter F. Entringer
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - David Majerowicz
- Departamento de Biotecnologia Farmacêutica, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Katia C. Gondim
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Zheng JC, Yue XR, Kuang WQ, Li SL, Tang R, Zhang ZF, Kurban A, Zhao C, Liu TX, Jing X. NPC1b as a novel target in controlling the cotton bollworm, Helicoverpa armigera. PEST MANAGEMENT SCIENCE 2020; 76:2233-2242. [PMID: 31976620 DOI: 10.1002/ps.5761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 01/06/2020] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Insects cannot synthesize sterols and must acquire them from food. The mechanisms underlying how insects uptake dietary sterols are largely unknown except that NPC1b, an integral membrane protein, has been shown to be responsible for dietary cholesterol uptake in Drosophila melanogaster. However, whether NPC1b orthologs in other insect species, particularly the economically important pests, function similarly remains to be determined. RESULTS In this study, we characterized the function of NPC1b in Helicoverpa armigera, a global pest that causes severe yield losses to many important crops. Limiting dietary cholesterol uptake to insects significantly inhibited food ingestion and weight gain. Compared to the wild-type H. armigera, the CRISPR/Cas9-edited NPC1b mutant larvae were incapable of getting adequate cholesterol and died in their early life stage. Gene expression profile and in situ hybridization analyses indicated that NPC1b was mainly expressed in the midgut where dietary cholesterol was absorbed. Expression of NPC1b was also correlated with the feeding life stages and was especially upregulated during early larval instars. Protein-ligand docking and sequence similarity analyses further demonstrated that NPC1b proteins of lepidopteran insects shared a relatively conserved cholesterol binding region, NPC1b_NTD, which, however, was highly divergent from bees-derived sequences. CONCLUSION NPC1b was crucial for dietary cholesterol uptake and growth of H. armigera, and therefore could serve as an insecticide target for the development of a novel pest-management approach to control this economically significant insect pest with little off-target effect on bees and sterol-autotrophic animals. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Jin-Cheng Zheng
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Basic Medical School, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China
| | - Xiao-Rong Yue
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Wen-Qing Kuang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Sa-Li Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Rui Tang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Zhan-Feng Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Anwar Kurban
- College of Agronomy, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Chaoyang Zhao
- College of Natural and Agricultural Sciences, University of California, Riverside, CA, USA
| | - Tong-Xian Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiangfeng Jing
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
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Jing X, Behmer ST. Insect Sterol Nutrition: Physiological Mechanisms, Ecology, and Applications. ANNUAL REVIEW OF ENTOMOLOGY 2020; 65:251-271. [PMID: 31600456 DOI: 10.1146/annurev-ento-011019-025017] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Insects, like all eukaryotes, require sterols for structural and metabolic purposes. However, insects, like all arthropods, cannot make sterols. Cholesterol is the dominant tissue sterol for most insects; insect herbivores produce cholesterol by metabolizing phytosterols, but not always with high efficiency. Many insects grow on a mixed-sterol diet, but this ability varies depending on the types and ratio of dietary sterols. Dietary sterol uptake, transport, and metabolism are regulated by several proteins and processes that are relatively conserved across eukaryotes. Sterol requirements also impact insect ecology and behavior. There is potential to exploit insect sterol requirements to (a) control insect pests in agricultural systems and (b) better understand sterol biology, including in humans. We suggest that future studies focus on the genetic mechanism of sterol metabolism and reverse transportation, characterizing sterol distribution and function at the cellular level, the role of bacterial symbionts in sterol metabolism, and interrupting sterol trafficking for pest control.
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Affiliation(s)
- Xiangfeng Jing
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China;
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Spencer T Behmer
- Department of Entomology, Texas A&M University, College Station, Texas 77843, USA;
- Ecology & Evolutionary Biology Graduate Program, Texas A&M University, College Station, Texas 77843, USA
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Singarapu KK, Ahuja A, Potula PR, Ummanni R. Solution Nuclear Magnetic Resonance Studies of Sterol Carrier Protein 2 Like 2 (SCP2L2) Reveal the Insecticide Specific Structural Characteristics of SCP2 Proteins in Aedes aegypti Mosquitoes. Biochemistry 2016; 55:4919-27. [DOI: 10.1021/acs.biochem.6b00322] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Kiran Kumar Singarapu
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Ashish Ahuja
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Purushotam Reddy Potula
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Ramesh Ummanni
- Center for NMR and Structural Chemistry and §Center for Chemical
Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
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NMR structure and function of Helicoverpa armigera sterol carrier protein-2, an important insecticidal target from the cotton bollworm. Sci Rep 2015; 5:18186. [PMID: 26655641 PMCID: PMC4674756 DOI: 10.1038/srep18186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/13/2015] [Indexed: 12/22/2022] Open
Abstract
The cotton bollworm, Helicoverpa armigera, has developed strong resistance to many insecticides. Sterol Carrier Protein-2 (SCP-2) is an important non-specific lipid transfer protein in insects and appears to be a potential new target. In order to elucidate the structure and function of Helicoverpa armigera SCP-2 (HaSCP-2), NMR spectroscopy, docking simulations, mutagenesis and bioassays were performed. HaSCP-2 composed of five α-helices and four stranded β-sheets. The folds of α-helices and β-sheets interacted together to form a hydrophobic cavity with putative entrance and exit openings, which served as a tunnel for accommodating and transporting of lipids. Several sterols and fatty acids could interact with HaSCP-2 via important hydrophobic sites, which could be potential targets for insecticides. Mutagenesis experiments indicated Y51, F53, F89, F110, I117 and Q131 may be the key functional sites. HaSCP-2 showed high cholesterol binding activity and SCP-2 inhibitors (SCPIs) could inhibit the biological activity of HaSCP-2. SCPI-treated larvae at young stage showed a significant decrease of cholesterol uptake in vivo. Our study describes for the first time a NMR structure of SCP-2 in lepidopteran H. armigera and reveals its important function in cholesterol uptake, which facilitates the screening of effective insecticides targeting the insect cholesterol metabolism.
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da Silva JBP, Navarro DMDAF, da Silva AG, Santos GKN, Dutra KA, Moreira DR, Ramos MN, Espíndola JWP, de Oliveira ADT, Brondani DJ, Leite ACL, Hernandes MZ, Pereira VRA, da Rocha LF, de Castro MCAB, de Oliveira BC, Lan Q, Merz KM. Thiosemicarbazones as Aedes aegypti larvicidal. Eur J Med Chem 2015; 100:162-75. [PMID: 26087027 DOI: 10.1016/j.ejmech.2015.04.061] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 01/21/2023]
Abstract
A set of aryl- and phenoxymethyl-(thio)semicarbazones were synthetized, characterized and biologically evaluated against the larvae of Aedes aegypti (A. aegypti), the vector responsible for diseases like Dengue and Yellow Fever. (Q)SAR studies were useful for predicting the activities of the compounds not included to create the QSAR model as well as to predict the features of a new compound with improved activity. Docking studies corroborated experimental evidence of AeSCP-2 as a potential target able to explain the larvicidal properties of its compounds. The trend observed between the in silico Docking scores and the in vitro pLC50 (equals -log LC50, at molar concentration) data indicated that the highest larvicidal compounds, or the compounds with the highest values for pLC50, are usually those with the higher docking scores (i.e., greater in silico affinity for the AeSCP-2 target). Determination of cytotoxicity for these compounds in mammal cells demonstrated that the top larvicide compounds are non-toxic.
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Affiliation(s)
- João Bosco P da Silva
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil.
| | - Daniela Maria do A F Navarro
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil.
| | - Aluizio G da Silva
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil
| | - Geanne K N Santos
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil
| | - Kamilla A Dutra
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil
| | - Diogo Rodrigo Moreira
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil
| | - Mozart N Ramos
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil
| | - José Wanderlan P Espíndola
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Ana Daura T de Oliveira
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Dalci José Brondani
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Ana Cristina L Leite
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Marcelo Zaldini Hernandes
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-521, Recife, PE, Brazil
| | - Valéria R A Pereira
- Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, 50670-420, Recife, PE, Brazil
| | - Lucas F da Rocha
- Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, 50670-420, Recife, PE, Brazil
| | - Maria Carolina A B de Castro
- Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, 50670-420, Recife, PE, Brazil
| | - Beatriz C de Oliveira
- Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, 50670-420, Recife, PE, Brazil
| | - Que Lan
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA
| | - Kenneth M Merz
- Quantum Theory Project, University of Florida, 2234 New Physics Building, Gainesville, PO Box 118435, Florida, USA
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Zhang L, Li D, Xu R, Zheng S, He H, Wan J, Feng Q. Structural and functional analyses of a sterol carrier protein in Spodoptera litura. PLoS One 2014; 9:e81542. [PMID: 24454688 PMCID: PMC3893073 DOI: 10.1371/journal.pone.0081542] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 10/23/2013] [Indexed: 11/19/2022] Open
Abstract
Backgrounds In insects, cholesterol is one of the membrane components in cells and a precursor of ecdysteroid biosynthesis. Because insects lack two key enzymes, squalene synthase and lanosterol synthase, in the cholesterol biosynthesis pathway, they cannot autonomously synthesize cholesterol de novo from simple compounds and therefore have to obtain sterols from their diet. Sterol carrier protein (SCP) is a cholesterol-binding protein responsible for cholesterol absorption and transport. Results In this study, a model of the three-dimensional structure of SlSCPx-2 in Spodoptera litura, a destructive polyphagous agricultural pest insect in tropical and subtropical areas, was constructed. Docking of sterol and fatty acid ligands to SlSCPx-2 and ANS fluorescent replacement assay showed that SlSCPx-2 was able to bind with relatively high affinities to cholesterol, stearic acid, linoleic acid, stigmasterol, oleic acid, palmitic acid and arachidonate, implying that SlSCPx may play an important role in absorption and transport of these cholesterol and fatty acids from host plants. Site-directed mutation assay of SlSCPx-2 suggests that amino acid residues F53, W66, F89, F110, I115, T128 and Q131 are critical for the ligand-binding activity of the SlSCPx-2 protein. Virtual ligand screening resulted in identification of several lead compounds which are potential inhibitors of SlSCPx-2. Bioassay for inhibitory effect of five selected compounds showed that AH-487/41731687, AG-664/14117324, AG-205/36813059 and AG-205/07775053 inhibited the growth of S. litura larvae. Conclusions Compounds AH-487/41731687, AG-664/14117324, AG-205/36813059 and AG-205/07775053 selected based on structural modeling showed binding affinity to SlSCPx-2 protein and inhibitory effect on the growth of S. litura larvae.
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Affiliation(s)
- Lili Zhang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Ding Li
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Rui Xu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Sichun Zheng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Hongwu He
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Jian Wan
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
- * E-mail: (QF); (JW)
| | - Qili Feng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- * E-mail: (QF); (JW)
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Du X, Ma H, Zhang X, Liu K, Peng J, Lan Q, Hong H. Characterization of the sterol carrier protein-x/sterol carrier protein-2 gene in the cotton bollworm, Helicoverpa armigera. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:1413-1423. [PMID: 22922458 DOI: 10.1016/j.jinsphys.2012.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 08/10/2012] [Accepted: 08/13/2012] [Indexed: 06/01/2023]
Abstract
Cholesterol is a membrane component and the precursor of ecdysteroids in insects, but insects cannot synthesize cholesterol de novo. Therefore, cholesterol uptake and transportation during the feeding larval stages are critical processes in insects. The sterol carrier protein-2 domain (SCP-2) in sterol carrier proteins-x (SCP-x) has been speculated to be involved in intracellular cholesterol transfer and metabolism in vertebrates. However, a direct association between SCP-x gene expression, cholesterol absorption and development in lepidopteran insects is poorly understood. We identified the Helicoverpa armigera sterol carrier protein-x/2 (HaSCP-x/2) gene from the larval midgut cDNAs. The HaSCP-x/2 gene is well conserved during evolution and relatively divergent in heterogenetic species. Transcripts of HaSCP-x/2 were detected by qRT-PCR at the highest level in the midgut of H. armigera during the larval stages. Expression knockdown of HaSCP-x/2 transcripts via dsRNA interference resulted in delayed larval development and decreased adult fecundity. Sterol carrier protein-2 inhibitors were lethal to young larvae and decreased fertility in adults emerged from treated elder larvae in H. armigera. The results taken together suggest that HaSCPx/2 gene is important for normal development and fertility in H. armigera.
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Affiliation(s)
- Xin Du
- College of Life Sciences, Central China Normal University, 100 Luoyu Road, Wuhan, Hubei 430079, PR China
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Jha RK, Chi H, Tang LC. A comparison of artificial diet and hybrid sweet corn for the rearing of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) based on life table characteristics. ENVIRONMENTAL ENTOMOLOGY 2012; 41:30-39. [PMID: 22525057 DOI: 10.1603/en11206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The demographic characteristics of Helicoverpa armigera (Hübner) reared on hybrid sweet corn (Zea mays L. variety saccharata) (hybrid super sweet corn KY bright jean) and on an artificial diet were compared by using the age-stage, two-sex life table. Because the hatch rate of eggs varies with maternal age, age-specific fecundity was calculated based on the numbers of hatched eggs to reveal the biological characteristics of H. armigera accurately. The intrinsic rate of increase (r), finite rate (λ) and mean generation time (T) of H. armigera were 0.0853 d(-1), 1.0890 d(-1), and 46.6 d, respectively, on Z. mays and 0.1015 d(-1), 1.1068 d(-1), and 46.3 d, respectively, on the artificial diet. There were significant differences in the intrinsic rate of increase and finite rate between two treatments. The age-stage life expectancy and reproductive value also were calculated. The relationships among the net reproductive rate, the mean female fecundity, the number of emerged females, and the total number of individuals used in the life table study are consistent with theoretical expectations. We recommend the age-stage, two-sex life table for use in insect demographic studies to incorporate both sexes and the variation in developmental rate among individuals and to obtain accurate population parameters. The artificial diet is more suitable for the mass rearing of H. armigera.
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Affiliation(s)
- Ratna K Jha
- Department of Entomology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
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