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Zhang BZ, Hu GL, Lu LY, Chen XL, Gao XW. Silencing of CYP6AS160 in Solenopsis invicta Buren by RNA interference enhances worker susceptibility to fipronil. BULLETIN OF ENTOMOLOGICAL RESEARCH 2022; 112:171-178. [PMID: 34365981 DOI: 10.1017/s0007485321000651] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cytochrome P450 monooxygenases play a key role in pest resistance to insecticides by detoxification. Four new P450 genes, CYP6AS160, CYP6AS161, CYP4AB73 and CYP4G232 were identified from Solenopsis invicta. CYP6AS160 was highly expressed in the abdomen and its expression could be induced significantly with exposure to fipronil, whereas CYP4AB73 was not highly expressed in the abdomen and its expression could not be significantly induced following exposure to fipronil. Expression levels of CYP6AS160 and CYP4AB73 in workers were significantly higher than that in queens. RNA interference-mediated gene silencing by feeding on double-stranded RNA (dsRNA) found that the levels of this transcript decreased (by maximum to 64.6%) when they fed on CYP6AS160-specific dsRNA. Workers fed dsCYP6AS160 had significantly higher mortality after 24 h of exposure to fipronil compared to controls. Workers fed dsCYP6AS160 had reduced total P450 activity of microsomal preparations toward model substrates p-nitroanisole. However, the knockdown of a non-overexpressed P450 gene, CYP4AB73 did not lead to an increase of mortality or a decrease of total P450 activity. The knockdown effects of CYP6AS160 on worker susceptibility to fipronil, combined with our other findings, indicate that CYP6AS160 is responsible for detoxification of fipronil. Feeding insects dsRNA may be a general strategy to trigger RNA interference and may find applications in entomological research and in the control of insect pests in the field.
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Affiliation(s)
- Bai-Zhong Zhang
- College of Resources and Environment, Henan Engineering Research Center of Biological Pesticide & Fertilizer Development and Synergistic Application, Henan Institute of Science and Technology, Xinxiang453003, P.R. China
- Department of Entomology, China Agricultural University, Beijing100193, P.R. China
| | - Gui-Lei Hu
- College of Resources and Environment, Henan Engineering Research Center of Biological Pesticide & Fertilizer Development and Synergistic Application, Henan Institute of Science and Technology, Xinxiang453003, P.R. China
| | - Liu-Yang Lu
- College of Resources and Environment, Henan Engineering Research Center of Biological Pesticide & Fertilizer Development and Synergistic Application, Henan Institute of Science and Technology, Xinxiang453003, P.R. China
| | - Xi-Ling Chen
- College of Resources and Environment, Henan Engineering Research Center of Biological Pesticide & Fertilizer Development and Synergistic Application, Henan Institute of Science and Technology, Xinxiang453003, P.R. China
| | - Xi-Wu Gao
- Department of Entomology, China Agricultural University, Beijing100193, P.R. China
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Shah JS, Renthal R. Antennal Proteome of the Solenopsis invicta (Hymenoptera: Formicidae): Caste Differences in Olfactory Receptors and Chemosensory Support Proteins. JOURNAL OF INSECT SCIENCE (ONLINE) 2020; 20:5937575. [PMID: 33098433 PMCID: PMC7585320 DOI: 10.1093/jisesa/ieaa118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Little is known about the expression pattern of odorant and pheromone transporters, receptors, and deactivation enzymes in the antennae of ants carrying out different tasks. In order to begin filling in this information gap, we compared the proteomes of the antennae of workers and males of the red fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Male ants do not perform any colony work, and their only activity is to leave the nest on a mating flight. Previous studies showed that male ants express fewer types of odorant receptors than workers. Thus, we expected to find large differences between male and worker antennae for expression of receptors, transporters, and deactivators of signaling chemicals. We found that the abundance of receptors was consistent with the expected caste-specific signaling complexity, but the numbers of different antenna-specific transporters and deactivating enzymes in males and workers were similar. It is possible that some of these proteins have antenna-specific functions that are unrelated to chemosensory reception. Alternatively, the similar complexity could be a vestige of ant progenitors that had more behaviorally active males. As the reduced behavior of male ants evolved, the selection process may have favored a complex repertoire of transporters and deactivating enzymes alongside a limited repertoire of odorant receptors.
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Affiliation(s)
- Jaee Shailesh Shah
- Department of Biology, University of Texas at San Antonio, San Antonio, TX
| | - Robert Renthal
- Department of Biology, University of Texas at San Antonio, San Antonio, TX
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Tissue, developmental, and caste-specific expression of odorant binding proteins in a eusocial insect, the red imported fire ant, Solenopsis invicta. Sci Rep 2016; 6:35452. [PMID: 27765943 PMCID: PMC5073229 DOI: 10.1038/srep35452] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/28/2016] [Indexed: 11/13/2022] Open
Abstract
Insects interact with the surrounding environment via chemoreception, and in social insects such as ants, chemoreception functions to mediate diverse behaviors including food acquisition, self/non-self recognition, and intraspecific communication. The invasive red imported fire ant, Solenopsis invicta, has spread worldwide, displaying a remarkable environmental adaptability. Odorant binding proteins (OBPs) are chemical compound carriers, involved in diverse physiological processes including odor detection and chemical transport. S. invicta contains a highly divergent 17-member OBP gene family, that includes an ant-specific expansion and the social organization implicated Gp-9 (OBP3) gene. A systematic gene expression analysis of the SiOBP repertoire was performed across social caste (workers, male and female alates), tissues (antennae, head, thorax, and abdomen), and developmental stages (egg, larvae, and pupae), revealing that although SiOBPs were expressed in the antennae, the major regions of expression were in the head and thorax across all castes, and the abdomen in male and female alates. SiOBPs were very highly expressed in female alates and at somewhat lower levels in male alates and workers. SiOBPs were differentially expressed, with unique signatures in various castes and tissues, suggesting functionality of SiOBPs beyond olfaction Expression patterns of SiOBP subgroups also showed relationships with their evolutionary relatedness.
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Zhang B, Zhang L, Cui R, Zeng X, Gao X. Cloning and Expression of Multiple Cytochrome P450 Genes: Induction by Fipronil in Workers of the Red Imported Fire Ant (Solenopsis invicta Buren). PLoS One 2016; 11:e0150915. [PMID: 26982576 PMCID: PMC4794187 DOI: 10.1371/journal.pone.0150915] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 02/22/2016] [Indexed: 11/19/2022] Open
Abstract
Both exogenous and endogenous compounds can induce the expression of cytochrome P450 genes. The insect cytochrome P450 genes related to insecticide resistance are likely to be expressed as the “first line of defense” when challenged with insecticides. In this study, four cytochrome P450 genes, SinvCYP6B1, SinvCYP6A1, SinvCYP4C1, and SinvCYP4G15, were firstly isolated from workers of the red imported fire ant (Solenopsis invicta) through rapid amplification of cDNA ends (RACE) and sequenced. The fipronil induction profiles of the four cytochrome P450 genes and the two previously isolated CYP4AB1 and CYP4AB2 were characterized in workers. The results revealed that the expression of SinvCYP6B1, SinvCYP6A1, CYP4AB2, and SinvCYP4G15, increased 1.4-fold and 1.3-fold more than those of acetone control, respectively, after 24 h exposure to fipronil at concentrations of 0.25 μg mL−1 (median lethal dose) and 0.56 μg mL−1 (90% lethal dose), while no significant induction of the expression of CYP4AB1 and SinvCYP4C1 was detected. Among these genes, SinvCYP6B1 was the most significantly induced, and its maximum expression was 3.6-fold higher than that in acetone control. These results might suggest that multiple cytochrome P450 genes are co-up-regulated in workers of the fire ant through induction mechanism when challenged with fipronil. These findings indicated that cytochrome P450 genes play an important role in the detoxification of insecticides and provide a theoretical basis for the mechanisms of insecticide metabolism in the fire ant.
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Affiliation(s)
- Baizhong Zhang
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China
- College of Natural Resources and Environment, Henan Institute of Science and Technology, Xinxiang 453003, P.R. China
| | - Lei Zhang
- Department of Entomology, China Agricultural University, Beijing 100193, P.R. China
| | - Rukun Cui
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China
| | - Xinnian Zeng
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China
- * E-mail: (XZ); (XG)
| | - Xiwu Gao
- Department of Entomology, China Agricultural University, Beijing 100193, P.R. China
- * E-mail: (XZ); (XG)
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5
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Li T, Cao C, Yang T, Zhang L, He L, Xi Z, Bian G, Liu N. A G-protein-coupled receptor regulation pathway in cytochrome P450-mediated permethrin-resistance in mosquitoes, Culex quinquefasciatus. Sci Rep 2015; 5:17772. [PMID: 26656663 PMCID: PMC4674712 DOI: 10.1038/srep17772] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/04/2015] [Indexed: 01/29/2023] Open
Abstract
Rhodopsin-like G protein-coupled receptors (GPCRs) are known to be involved in the GPCR signal transduction system and regulate many essential physiological processes in organisms. This study, for the first time, revealed that knockdown of the rhodopsin-like GPCR gene in resistant mosquitoes resulted in a reduction of mosquitoes’ resistance to permethrin, simultaneously reducing the expression of two cAMP-dependent protein kinase A genes (PKAs) and four resistance related cytochrome P450 genes. The function of rhodopsin-like GPCR was further confirmed using transgenic lines of Drosophila melanogaster, in which the tolerance to permethrin and the expression of Drosophila resistance P450 genes were both increased. The roles of GPCR signaling pathway second messenger cyclic adenosine monophosphate (cAMP) and downstream effectors PKAs in resistance were investigated using cAMP production inhibitor Bupivacaine HCl and the RNAi technique. Inhibition of cAMP production led to significant decreases in both the expression of four resistance P450 genes and two PKA genes and mosquito resistance to permethrin. Knockdown of the PKA genes had shown the similar effects on permethrin resistance and P450 gene expression. Taken together, our studies revealed, for the first time, the role of the GPCR/cAMP/PKA-mediated regulatory pathway governing P450 gene expression and P450-mediated resistance in Culex mosquitoes.
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Affiliation(s)
- Ting Li
- Department of Entomology and Plant Pathology, Auburn University, Auburn AL 36849
| | - Chuanwang Cao
- Department of Entomology and Plant Pathology, Auburn University, Auburn AL 36849
| | - Ting Yang
- Department of Entomology and Plant Pathology, Auburn University, Auburn AL 36849
| | - Lee Zhang
- Genomics Laboratory, Auburn University, Auburn, AL 36849
| | - Lin He
- Department of Entomology and Plant Pathology, Auburn University, Auburn AL 36849
| | - Zhiyong Xi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Guowu Bian
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Nannan Liu
- Department of Entomology and Plant Pathology, Auburn University, Auburn AL 36849
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Du J, Liao C, Zhou H, Diao X, Li Y, Zheng P, Wang F. Gene cloning and expression analysis of AhR and CYP4 from Pinctada martensii after exposed to pyrene. ECOTOXICOLOGY (LONDON, ENGLAND) 2015; 24:1574-1582. [PMID: 25666496 DOI: 10.1007/s10646-015-1424-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/29/2015] [Indexed: 06/04/2023]
Abstract
Pyrene, a typical polycyclic aromatic hydrocarbon, is a common pollutant in the marine environment. Polycyclic aromatic hydrocarbons initiate cellular detoxification in an exposed organism via the activation of the aryl hydrocarbon receptor (AhR). Subsequent metabolism of these xenobiotics is mainly by the cytochrome P450 enzymes of the phase I detoxification system. Full-length complementary DNA sequences from the pearl oyster Pinctada martensii (pm) encoding AhR and cytochrome P4 were cloned. The P. martensii AhR complementary DNA sequence constitutes an open reading frame that encodes for 848 amino acids. Sequence analysis indicated PmAhR showed high similarity with its homologues of other bivalve species. The cytochrome P(CYP)4 complementary DNA sequence of P. martensii constitutes an open reading frame that encodes for 489 amino acids. Quantitative real-time analysis detected both PmAhR and PmCYP4 messenger RNA expressions in the mantle, gill, hepatapancreas and adductor muscle of P. martensii exposed to pyrene. The highest transcript-band intensities of PmAhR and PmCYP4 were observed in the gill. Temporal expression of PmAhR and PmCYP4 messenger RNAs induction was observed in gills and increased between 3 and 5 days post exposure; then returned to control level. These results suggest that messenger RNAs of PmAhR and PmCYP4 in pearl oysters might be useful parameters for monitoring marine environment pyrene pollution.
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Affiliation(s)
- Junqiao Du
- College of Environment and Plant Protection, Hainan University, Haikou, 570228, China
- Haikou Key Laboratory of Environment Toxicology, Hainan University, Haikou, 570228, China
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Hainan University, Haikou, 570228, China
| | - Chenghong Liao
- College of Agriculture, Hainan University, Haikou, 570228, China
- Haikou Key Laboratory of Environment Toxicology, Hainan University, Haikou, 570228, China
| | - Hailong Zhou
- College of Agriculture, Hainan University, Haikou, 570228, China
- Haikou Key Laboratory of Environment Toxicology, Hainan University, Haikou, 570228, China
| | - Xiaoping Diao
- College of Agriculture, Hainan University, Haikou, 570228, China.
- Haikou Key Laboratory of Environment Toxicology, Hainan University, Haikou, 570228, China.
| | - Yuhu Li
- College of Agriculture, Hainan University, Haikou, 570228, China
- Haikou Key Laboratory of Environment Toxicology, Hainan University, Haikou, 570228, China
| | - Pengfei Zheng
- College of Agriculture, Hainan University, Haikou, 570228, China
- Haikou Key Laboratory of Environment Toxicology, Hainan University, Haikou, 570228, China
| | - Fuqiang Wang
- College of Environment and Plant Protection, Hainan University, Haikou, 570228, China
- Haikou Key Laboratory of Environment Toxicology, Hainan University, Haikou, 570228, China
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Ravlić S, Žučko J, Tanković MS, Fafanđel M, Bihari N. Sequence analysis of novel CYP4 transcripts from Mytilus galloprovincialis. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:300-309. [PMID: 26176904 DOI: 10.1016/j.etap.2015.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 05/29/2015] [Accepted: 06/02/2015] [Indexed: 06/04/2023]
Abstract
Cytochrome P450 enzymes (CYPs) are essential components of cellular detoxification system. We identified and characterized seven new cytochrome P450 gene transcript clusters in the populations of bivalve mollusc Mytilus galloprovincialis from three different locations. The phylogenetic analysis identified all transcripts as clusters within the CYP4 branch. Identified clusters, each comprising a number of transcript variants, were designated CYP4Y1, Y2, Y3, Y4, Y5, Y6 and Y7. Transcript clusters CYP4Y2 and Y7, and CYP4Y5 and Y6 showed site specificity, while the transcript clusters CYP4Y1, Y3 and Y4 were present at all investigated locations. The comparison of transcripts deduced amino acid sequences with CYP4s from vertebrate and invertebrate species showed high conservation of the residues and domains essential to the putative function of the enzyme, as terminal ω-hydroxylation and prostaglandin hydroxylation. Our results suggest the great expansion of the CYP4Y cDNAs indicative of CYP4 proteins in the mussel M. galloprovincialis presumably as a response to different environmental conditions.
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Affiliation(s)
- Sanda Ravlić
- Center for Marine Research, Ruđer Bošković Institute, Giordano Paliaga 5, 52210 Rovinj, Croatia.
| | - Jurica Žučko
- Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Mirta Smodlaka Tanković
- Center for Marine Research, Ruđer Bošković Institute, Giordano Paliaga 5, 52210 Rovinj, Croatia
| | - Maja Fafanđel
- Center for Marine Research, Ruđer Bošković Institute, Giordano Paliaga 5, 52210 Rovinj, Croatia
| | - Nevenka Bihari
- Center for Marine Research, Ruđer Bošković Institute, Giordano Paliaga 5, 52210 Rovinj, Croatia
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8
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Lucas C, Nicolas M, Keller L. Expression of foraging and Gp-9 are associated with social organization in the fire ant Solenopsis invicta. INSECT MOLECULAR BIOLOGY 2015; 24:93-104. [PMID: 25315753 DOI: 10.1111/imb.12137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aim of this study was to investigate levels of expression of two major genes, the odorant binding protein Gp-9 (general protein-9) and foraging, that have been shown to be associated with behavioural polymorphisms in ants. We analysed workers and young nonreproductive queens collected from nests of the monogyne (single reproductive queen per nest) and polygyne (multiple reproductive queens) social forms of Solenopsis invicta. In workers but not young queens, the level of foraging expression was significantly associated with social form and the task performed (ie localization in the nest or foraging area). The level of expression of Gp-9 was also associated with social form and worker localization. In addition there was a higher level of expression of the Gp-9(b) allele compared with the Gp-9(B) allele in the heterozygote workers and the young nonreproductive queens. Finally, in the polygyne colonies the level of expression of foraging was not significantly associated with the Gp-9 genotype for either workers or young nonreproductive queens, suggesting that both genes have independent non-epistatic effects on behaviour in S. invicta.
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Affiliation(s)
- C Lucas
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland; Institut de Recherche sur la Biologie de l'Insecte (UMR 7261), CNRS, University of Tours, Tours, France
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Pan L, Liu N, Xu C, Miao J. Identification of a novel P450 gene belonging to the CYP4 family in the clam Ruditapes philippinarum, and analysis of basal- and benzo(a)pyrene-induced mRNA expression levels in selected tissues. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2011; 32:390-398. [PMID: 22004958 DOI: 10.1016/j.etap.2011.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 06/23/2011] [Accepted: 08/06/2011] [Indexed: 05/31/2023]
Abstract
A novel full-length cDNA encoding a CYP4 protein was initially cloned from the clam, Ruditapes philippinarum. The nucleotide sequence contained an open reading frame coding for 442 amino acids and the deduced amino acid sequence showed 42.6-49.1% identity with other species CYP4s. The phylogenetic analysis demonstrated that the clam CYP4 was clustered within the CYP4s branch. The clam CYP4 mRNA expression was detected in gill, digestive gland, adductor muscle and mantle, and highest transcription level was observed in digestive gland compared to other tissues. Quantitative real-time RT-PCR analysis revealed that there was no notable change in CYP4 mRNA expression in gill of R. philippinarum exposure to benzo(a)pyrene (BaP), while the mRNA expression was induced significantly in the digestive gland of the clam by 0.2 ppb (μgL(-1)) BaP (p<0.05). The results suggest that CYP4 of the clam may serve as a useful biomarker of marine environmental PAH pollution.
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Affiliation(s)
- Luqing Pan
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China.
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10
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Liu N, Li T, Reid WR, Yang T, Zhang L. Multiple Cytochrome P450 genes: their constitutive overexpression and permethrin induction in insecticide resistant mosquitoes, Culex quinquefasciatus. PLoS One 2011; 6:e23403. [PMID: 21858101 PMCID: PMC3155542 DOI: 10.1371/journal.pone.0023403] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/15/2011] [Indexed: 12/02/2022] Open
Abstract
Four cytochrome P450 cDNAs, CYP6AA7, CYP9J40, CYP9J34, and CYP9M10, were isolated from mosquitoes, Culex quinquefasciatus. The P450 gene expression and induction by permethrin were compared for three different mosquito populations bearing different resistance phenotypes, ranging from susceptible (S-Lab), through intermediate (HAmCqG0, the field parental population) to highly resistant (HAmCqG8, the 8th generation of permethrin selected offspring of HAmCqG0). A strong correlation was found for P450 gene expression with the levels of resistance and following permethrin selection at the larval stage of mosquitoes, with the highest expression levels identified in HAmCqG8, suggesting the importance of CYP6AA7, CYP9J40, CYP9J34, and CYP9M10 in the permethrin resistance of larva mosquitoes. Only CYP6AA7 showed a significant overexpression in HAmCqG8 adult mosquitoes. Other P450 genes had similar expression levels among the mosquito populations tested, suggesting different P450 genes may be involved in the response to insecticide pressure in different developmental stages. The expression of CYP6AA7, CYP9J34, and CYP9M10 was further induced by permethrin in resistant mosquitoes. Taken together, these results indicate that multiple P450 genes are up-regulated in insecticide resistant mosquitoes through both constitutive overexpression and induction mechanisms, thus increasing the overall expression levels of P450 genes.
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Affiliation(s)
- Nannan Liu
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America.
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Oakeshott JG, Johnson RM, Berenbaum MR, Ranson H, Cristino AS, Claudianos C. Metabolic enzymes associated with xenobiotic and chemosensory responses in Nasonia vitripennis. INSECT MOLECULAR BIOLOGY 2010; 19 Suppl 1:147-163. [PMID: 20167025 DOI: 10.1111/j.1365-2583.2009.00961.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The numbers of glutathione S-transferase, cytochrome P450 and esterase genes in the genome of the hymenopteran parasitoid Nasonia vitripennis are about twice those found in the genome of another hymenopteran, the honeybee Apis mellifera. Some of the difference is associated with clades of these families implicated in xenobiotic resistance in other insects and some is in clades implicated in hormone and pheromone metabolism. The data support the hypothesis that the eusocial behaviour of the honeybee and the concomitant homeostasis of the nest environment may obviate the need for as many gene/enzyme systems associated with xenobiotic metabolism as are found in other species, including N. vitripennis, that are thought to encounter a wider range of potentially toxic xenobiotics in their diet and habitat.
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Affiliation(s)
- J G Oakeshott
- Commonwealth Scientific and Industrial Research Organisation Entomology, Acton, ACT, Australia.
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12
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Gotzek D, Ross KG. Current status of a model system: the gene Gp-9 and its association with social organization in fire ants. PLoS One 2009; 4:e7713. [PMID: 19893635 PMCID: PMC2767508 DOI: 10.1371/journal.pone.0007713] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 10/07/2009] [Indexed: 11/18/2022] Open
Abstract
The Gp-9 gene in fire ants represents an important model system for studying the evolution of social organization in insects as well as a rich source of information relevant to other major evolutionary topics. An important feature of this system is that polymorphism in social organization is completely associated with allelic variation at Gp-9, such that single-queen colonies (monogyne form) include only inhabitants bearing B-like alleles while multiple-queen colonies (polygyne form) additionally include inhabitants bearing b-like alleles. A recent study of this system by Leal and Ishida (2008) made two major claims, the validity and significance of which we examine here. After reviewing existing literature, analyzing the methods and results of Leal and Ishida (2008), and generating new data from one of their study sites, we conclude that their claim that polygyny can occur in Solenopsis invicta in the U.S.A. in the absence of expression of the b-like allele Gp-9(b) is unfounded. Moreover, we argue that available information on insect OBPs (the family of proteins to which GP-9 belongs), on the evolutionary/population genetics of Gp-9, and on pheromonal/behavioral control of fire ant colony queen number fails to support their view that GP-9 plays no role in the chemosensory-mediated communication that underpins regulation of social organization. Our analyses lead us to conclude that there are no new reasons to question the existing consensus view of the Gp-9 system outlined in Gotzek and Ross (2007).
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Affiliation(s)
- Dietrich Gotzek
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
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Wang H, Zhang L, Zhang L, Lin Q, Liu N. Arginine kinase: differentiation of gene expression and protein activity in the red imported fire ant, Solenopsis invicta. Gene 2008; 430:38-43. [PMID: 19028554 DOI: 10.1016/j.gene.2008.10.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 10/01/2008] [Accepted: 10/16/2008] [Indexed: 11/24/2022]
Abstract
Arginine kinase (AK), a primary enzyme in cell metabolism and adenosine 5'-triphosphate (ATP)-consuming processes, plays an important role in cellular energy metabolism and maintaining constant ATP levels in invertebrate cells. In order to identify genes that are differentially expressed between larvae and adults, queens and workers, and female alates (winged) and queens (wingless), AK cDNA was obtained from the red imported fire ant. The cDNA sequence of the gene has open reading frames of 1065 nucleotides, encoding a protein of 355 amino acid residues that includes the substrate recognition region, the signature sequence pattern of ATP:guanidino kinases, and an "actinin-type" actin binding domain. Northern blot analysis and protein activity analysis demonstrated that the expression of the AK gene and its protein activity were developmentally, caste specifically, and tissue specifically regulated in red imported fire ants with a descending order of worker> alate (winged adult) female> alate (winged adult) male> larvae> worker pupae approximately alate pupae. These results suggest a different demand for energy-consumption and production in the different castes of the red imported fire ant, which may be linked to their different missions and physiological activities in the colonies. The highest level of the AK gene expression and activity was identified in head tissue of both female alates and workers and thorax tissue of workers, followed by thorax tissue of female alates and abdomen tissue of male alates, suggesting the main tissues or cells in these body parts, such as brain, neurons and muscles, which have been identified as the major tissues and/or cells that display high and variable rates of energy turnover in other organisms, play a key role in energy production and its utilization in the fire ant. In contrast, in the male alate, the highest AK expression and activity were found in the abdomen, suggesting that here energy demand may relate to sperm formation and reproduction.
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Affiliation(s)
- Haichuan Wang
- Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn University, Auburn, AL 36849-5413, USA
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Smith CR, Toth AL, Suarez AV, Robinson GE. Genetic and genomic analyses of the division of labour in insect societies. Nat Rev Genet 2008; 9:735-48. [PMID: 18802413 DOI: 10.1038/nrg2429] [Citation(s) in RCA: 228] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Division of labour--individuals specializing in different activities--features prominently in the spectacular success of the social insects. Until recently, genetic and genomic analyses of division of labour were limited to just a few species. However, research on an ever-increasing number of species has provided new insight, from which we highlight two results. First, heritable influences on division of labour are more pervasive than previously imagined. Second, different forms of division of labour, in lineages in which eusociality has arisen independently, have evolved through changes in the regulation of highly conserved molecular pathways associated with several basic life-history traits, including nutrition, metabolism and reproduction.
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Affiliation(s)
- Chris R Smith
- Program in Ecology and Evolutionary Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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15
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Zhu F, Liu N. Differential expression of CYP6A5 and CYP6A5v2 in pyrethroid-resistant house flies, Musca domestica. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2008; 67:107-119. [PMID: 18163524 DOI: 10.1002/arch.20225] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two cytochrome P450 alleles, CYP6A5 and CYP6A5v2, were isolated from a pyrethroid-resistant house fly stain, ALHF. The two alleles shared 98% similarity in amino acid sequence. To understand the importance of these two alleles in resistance and examine the expression profile of the two alleles between resistant and susceptible strains, quantitative real-time PCR (qRT-PCR) was performed and compared with the Northern blot analysis. We found that qRT-PCR was an efficient method to characterize the expression profiles between these two sequence-closely-related P450 genes between resistant and susceptible houses flies. One of them, CYP6A5v2, was constitutively overexpressed in ALHF house flies compared with susceptible house fly strains. Moreover, this gene was predominantly expressed in the abdominal tissues of ALHF, in which the primary detoxification organs of insects are located. However, there was no significant difference in the expression of CYP6A5 between ALHF and susceptible house flies. The genetic linkage analysis was conducted to determine the possible link between the constitutively overexpressed CYP6A5v2 and insecticide resistance. CYP6A5v2 was mapped on autosome 5, which is correlated with the linkage of resistance in ALHF. Taken together, the study suggests the importance of CYP6A5v2 in increasing metabolic detoxification of insecticides in ALHF. The distinct expression of CYP6A5 and CYP6A5v2 in resistant and susceptible house flies implies the functional difference of theses two genes in house flies and suggests that they are two recently diverged P450 genes presented in a single organism.
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Affiliation(s)
- Fang Zhu
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama 36849-5413, USA
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16
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Zhu F, Feng JN, Zhang L, Liu N. Characterization of two novel cytochrome P450 genes in insecticide-resistant house-flies. INSECT MOLECULAR BIOLOGY 2008; 17:27-37. [PMID: 18237282 DOI: 10.1111/j.1365-2583.2008.00777.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two novel P450 cDNAs, CYP6A36 and CYP6A37, were isolated from house-flies. Putative protein sequences deduced from the cDNA sequences shared 58% identity. Predicted protein sequences of CYP6A36 and CYP6A37 from pyrethroid-resistant ALHF house-flies were identical to their corresponding orthologues in susceptible aabys flies. Expression of CYP6A36 was developmentally regulated with significant overexpression in ALHF compared with susceptible CS flies. Overexpression of CYP6A36 was detected in ALHF abdomen, where the primary detoxification organs of the midgut and fat body are located. CYP6A37, however, was expressed in all tested life stages, with no significant difference in expression between ALHF and CS. Genetic linkage analysis located CYP6A36 on autosome 5; overexpression of CYP6A36 was linked to the factors on autosomes 1 and 2, corresponding to the linkage of P450-mediated resistance in ALHF. This evidence suggests the importance of CYP6A36 in detoxification of insecticides and evolution of insecticide resistance in ALHF.
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Affiliation(s)
- F Zhu
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
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17
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Gotzek D, Ross KG. Genetic regulation of colony social organization in fire ants: an integrative overview. QUARTERLY REVIEW OF BIOLOGY 2007; 82:201-26. [PMID: 17937246 DOI: 10.1086/519965] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Expression of colony social organization in fire ants appears to be under the control of a single Mendelian factor of large effect. Variation in colony queen number in Solenopsis invicta and its relatives is associated with allelic variation at the gene Gp-9, but not with variation at other unlinked genes; workers regulate queen identity and number on the basis of Gp-9 genotypic compatibility. Nongenetic factors, such as prior social experience, queen reproductive status, and local environment, have negligible effects on queen numbers which illustrates the nearly complete penetrance of Gp-9. As predicted, queen number can be manipulated experimentally by altering worker Gp-9 genotype frequencies. The Gp-9 allele lineage associated with polygyny in South American fire ants has been retained across multiple speciation events, which may signal the action of balancing selection to maintain social polymorphism in these species. Moreover, positive selection is implicated in driving the molecular evolution of Gp-9 in association with the origin of polygyny. The identity of the product of Gp-9 as an odorant-binding protein suggests plausible scenarios for its direct involvement in the regulation of queen number via a role in chemical communication. While these and other lines of evidence show that Gp-9 represents a legitimate candidate gene of major effect, studies aimed at determining (i) the biochemical pathways in which GP-9 functions; (ii) the phenotypic effects of molecular variation at Gp-9 and other pathway genes; and (iii) the potential involvement of genes in linkage disequilibrium with Gp-9 are needed to elucidate the genetic architecture underlying social organization in fire ants. Information that reveals the links between molecular variation, individual phenotype, and colony-level behaviors, combined with behavioral models that incorporate details of the chemical communication involved in regulating queen number, will yield a novel integrated view of the evolutionary changes underlying a key social adaptation.
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Affiliation(s)
- Dietrich Gotzek
- Department of Ecology and Evolution, University of Lausanne 1015 Lausanne, Switzerland.
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18
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Weil T, Rehli M, Korb J. Molecular basis for the reproductive division of labour in a lower termite. BMC Genomics 2007; 8:198. [PMID: 17598892 PMCID: PMC1988835 DOI: 10.1186/1471-2164-8-198] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 06/28/2007] [Indexed: 11/17/2022] Open
Abstract
Background Polyphenism, the expression of different phenotypes with the same genetic background, is well known for social insects. The substantial physiological and morphological differences among the castes generally are the result of differential gene expression. In lower termites, workers are developmentally flexible to become neotenic replacement reproductives via a single moult after the death of the founding reproductives. Thus, both castes (neotenics and workers) are expected to differ mainly in the expression of genes linked to reproductive division of labour, which constitutes the fundamental basis of insect societies. Results Representational difference analysis of cDNAs was used to study differential gene expression between neotenics and workers in the drywood termite Cryptotermes secundus (Kalotermitidae). We identified and, at least partially cloned five novel genes that were highly expressed in female neotenics. Quantitative real-time PCR analysis of all five genes in different castes (neotenics, founding reproductives, winged sexuals and workers of both sexes) confirmed the differential expression patterns. In addition, the relative expression of these genes was determined in three body parts of female neotenics (head, thorax, and abdomen) using quantitative real-time PCR. Conclusion The identified genes could be involved in the control and regulation of reproductive division of labour. Interestingly, this study revealed an expression pattern partly similar to social Hymenoptera indicating both common and species-specific regulatory mechanisms in hemimetabolous and holometabolous social insects.
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Affiliation(s)
- Tobias Weil
- Biologie I, Universität Regensburg, Universitätsstrasse 31, 93040 Regensburg, Germany
- Hämatologie und Onkologie, Klinikum der Universität Regensburg, Franz-Josef-Strauss-Allee-11, 93053 Regensburg, Germany
| | - Michael Rehli
- Hämatologie und Onkologie, Klinikum der Universität Regensburg, Franz-Josef-Strauss-Allee-11, 93053 Regensburg, Germany
| | - Judith Korb
- Biologie I, Universität Regensburg, Universitätsstrasse 31, 93040 Regensburg, Germany
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Huber DPW, Erickson ML, Leutenegger CM, Bohlmann J, Seybold SJ. Isolation and extreme sex-specific expression of cytochrome P450 genes in the bark beetle, Ips paraconfusus, following feeding on the phloem of host ponderosa pine, Pinus ponderosa. INSECT MOLECULAR BIOLOGY 2007; 16:335-49. [PMID: 17433069 DOI: 10.1111/j.1365-2583.2007.00731.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We have identified cDNAs and characterized the expression of 13 novel cytochrome P450 genes of potential importance in host colonization and reproduction by the California fivespined ips, Ips paraconfusus. Twelve are of the Cyp4 family and one is of the Cyp9 family. Following feeding on host Pinus ponderosa phloem, bark beetle transcript levels of several of the Cyp4 genes increased or decreased in males only or in both sexes. In one instance (IparaCyp4A5) transcript accumulated significantly in females, but declined significantly in males. The Cyp9 gene (Cyp9T1) transcript levels in males were > 85 000 x higher at 8 h and > 25 000 x higher at 24 h after feeding compared with nonfed controls. Transcript levels in females were approximately 150 x higher at 24 h compared with nonfed controls. Cyp4G27 transcript was present constitutively regardless of sex or feeding and served as a better housekeeping gene than beta-actin or 18S rRNA for the real-time TaqMan polymerase chain reaction analysis. The expression patterns of Cyp4AY1, Cyp4BG1, and, especially, Cyp9T1 in males suggest roles for these genes in male-specific aggregation pheromone production. The differential transcript accumulation patterns of these bark beetle P450s provide insight into ecological interactions of I. paraconfusus with its host pines.
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Affiliation(s)
- D P W Huber
- University of California, Davis, Department of Entomology, Davis, CA, USA
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20
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Liu N, Liu H, Zhu F, Zhang L. Differential expression of genes in pyrethroid resistant and susceptible mosquitoes, Culex quinquefasciatus (S.). Gene 2007; 394:61-8. [PMID: 17382491 DOI: 10.1016/j.gene.2007.01.032] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Revised: 01/24/2007] [Accepted: 01/26/2007] [Indexed: 01/08/2023]
Abstract
The transcriptional regulation of gene expression is a primary means by which insects adapt to a changing environment. The evolution of insecticide resistance is conferred through mechanisms, typically requiring the interaction of multiple genes. Consequently, the characterization of gene regulation and interactions in resistance is fundamental for achieving an understanding of the complex processes responsible for resistance. cDNA macroarray technology offers a promising new approach for investigating the complicated processes responsible for resistance development by revealing the interrelations of all of the elements in a resistant system simultaneously. In the current study, we compared the gene expression profiles of resistant and susceptible Culex quinquefasciatus mosquitoes, using a combination of subtractive PCR hybridization and cDNA microarray technique. By screening of 1500 cDNA clones from a resistant-susceptible mosquito subtractive library, we identified a set of genes with up-regulated expression in insecticide resistant Culex mosquitoes through transcriptional profiling compared to those in susceptible mosquitoes. These genes are vital for cellular and molecular metabolism, signal transduction, vesicular and molecular transport, protein biosynthesis, ubiquitination, and neuronal survival, but most have not previously been implicated in insecticide resistance. Functional studies of resistance-associated up-regulated genes should shed new light on both the molecular basis of resistance and the regulatory pathways that lead to it.
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Affiliation(s)
- Nannan Liu
- Department of Entomology and Plant Pathology, Auburn University, Auburn AL 36849, USA.
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Claudianos C, Ranson H, Johnson RM, Biswas S, Schuler MA, Berenbaum MR, Feyereisen R, Oakeshott JG. A deficit of detoxification enzymes: pesticide sensitivity and environmental response in the honeybee. INSECT MOLECULAR BIOLOGY 2006; 15:615-36. [PMID: 17069637 PMCID: PMC1761136 DOI: 10.1111/j.1365-2583.2006.00672.x] [Citation(s) in RCA: 453] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The honeybee genome has substantially fewer protein coding genes ( approximately 11 000 genes) than Drosophila melanogaster ( approximately 13 500) and Anopheles gambiae ( approximately 14 000). Some of the most marked differences occur in three superfamilies encoding xenobiotic detoxifying enzymes. Specifically there are only about half as many glutathione-S-transferases (GSTs), cytochrome P450 monooxygenases (P450s) and carboxyl/cholinesterases (CCEs) in the honeybee. This includes 10-fold or greater shortfalls in the numbers of Delta and Epsilon GSTs and CYP4 P450s, members of which clades have been recurrently associated with insecticide resistance in other species. These shortfalls may contribute to the sensitivity of the honeybee to insecticides. On the other hand there are some recent radiations in CYP6, CYP9 and certain CCE clades in A. mellifera that could be associated with the evolution of the hormonal and chemosensory processes underpinning its highly organized eusociality.
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Affiliation(s)
- C Claudianos
- Research School of Biological Sciences, Australian National University, Canberra, ACT, Australia.
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22
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Liénard MA, Lassance JMXS, Paulmier I, Picimbon JF, Löfstedt C. Differential expression of cytochrome c oxidase subunit III gene in castes of the termite Reticulitermes santonensis. JOURNAL OF INSECT PHYSIOLOGY 2006; 52:551-7. [PMID: 16545394 DOI: 10.1016/j.jinsphys.2006.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Revised: 02/02/2006] [Accepted: 02/06/2006] [Indexed: 05/07/2023]
Abstract
Social insects such as termites live in colonies in which cooperation is assumed by all individuals developing into castes to which specific tasks are allocated. Little has been reported about molecular aspects underlying termite caste-specific gene expression. Genetic regulation has recently been hypothesized to govern caste-specific traits and physiology in social insects. Cytochrome c oxidase (COX) has been shown to be an interesting candidate for expression study in insects. We used the cytochrome c oxidase subunit III gene (COXIII) that was cloned from mRNA in a lower termite, Reticulitermes santonensis De Feytaud (Isoptera; Rhinotermitidae). The full-length cDNA encodes a protein of 262 amino acids that shows high degree of homology with other insects COXIIIs. Reverse transcriptase-PCR and real-time PCR were performed to compare gene expression between larvae, workers, nymphs and soldiers. Analyses performed on head cDNAs revealed that COXIII is differentially expressed between castes. The level of COXIII is caste-regulated with an increase in workers (approximately 1.9-fold) and nymphs (approximately 2.8-fold) and a decrease in soldiers (0.8-fold) compared to the expression level in larvae (1.0-fold). These results may emphasize the physiological importance of COX in the termite brain at different developmental stages.
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Affiliation(s)
- Marjorie A Liénard
- Department of Ecology, Lund University, Sölvegatan 37, SE-223 62 Lund, Sweden.
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23
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Cornette R, Koshikawa S, Hojo M, Matsumoto T, Miura T. Caste-specific cytochrome P450 in the damp-wood termite Hodotermopsis sjostedti (Isoptera, Termopsidae). INSECT MOLECULAR BIOLOGY 2006; 15:235-44. [PMID: 16640734 DOI: 10.1111/j.1365-2583.2006.00632.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Termites are eusocial insects with a well-defined caste system, which is an example of polyphenism. This polyphenism is based on hormonally controlled differential gene expression. In the damp-wood termite Hodotermopsis sjostedti, we induced differentiation into the soldier caste by using juvenile hormone analogue treatment. We then investigated specific gene expression, which appeared during the hormonal response and triggered caste differentiation, using fluorescent differential display. A candidate cDNA sequence with similarity to cytochromes P450, CYP6AM1, was characterized and its transcript shown to be repressed between 1 and 3 days after hormone treatment. CYP6AM1 was specifically expressed in the fat body of pseudergates and soldiers. The putative function of this P450 is discussed with respect to the caste differentiation system.
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Affiliation(s)
- R Cornette
- Department of Biology, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
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Fritz GN, Vander Meer RK, Preston CA. Selective male mortality in the red imported fire ant, Solenopsis invicta. Genetics 2006; 173:207-13. [PMID: 16489215 PMCID: PMC1461442 DOI: 10.1534/genetics.106.056358] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Males in polygyne populations of Solenopsis invicta are primarily sterile diploids and thought to not express the Gp-9 gene coding for a pheromone-binding protein affecting complex social behavior. We examined an aspect of the breeding system hitherto not considered--male Gp-9 genotypes in relation to sperm stored in queens. Four sites with varying frequencies of sympatric monogyne and polygyne colonies were sampled, including sexuals, workers, and broods from four colonies. Most queens were heterozygotes storing B sperm. Although predicted to be common, only 14 of 504 males were B or BB genotypes, suggesting strong selection. Increased frequency of polygyne colonies at each site paralleled increases in queens with b sperm (1.9-32.8%) and of noninseminated queens. The presence of both B and b sperm in 1.9-18.9% of queens, genotype profiles of colonies, and genotypes of offspring from individual queens suggest some frequency of multiple mating. The bb genotype, rather than an obligate, developmental lethal, was present in some queens and common in alates, workers, and brood. Selective mortality of sexuals may affect multiple aspects of the breeding system, including female-mediated dispersal, mating success, and gene flow.
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Affiliation(s)
- Gary N Fritz
- Department of Biological Sciences, Eastern Illinois University, Charleston 61920, USA.
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