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Batcha MM, Ahamed AS, Peng CF. Identification of a new type of haematopoietic progenitor kinase-interacting protein (HIP-55) in Aedes aegypti mosquito haemocytes and its involvement in immunity-like functions in mosquito: a molecular study. Parasitol Res 2019; 118:2509-2521. [PMID: 31377908 DOI: 10.1007/s00436-019-06408-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 07/25/2019] [Indexed: 11/26/2022]
Abstract
In this study, we characterize the HIP-55 protein in the mosquito Aedes aegypti for the first time. HIP-55 is a 55-kDa HPK1-interacting protein that is also called SH3P7. HIP-55 constitutively binds HPK1 'via' an HPK1 proline-rich motif 2(PR2) through its C-terminal SH3 domain. HIP-55 critically interacts with ZAP-70, and this interaction was induced by TCR signalling. ZAP-70 phosphorylated HIP-55 at Tyr-334 and Tyr-344 in vitro and in vivo. In our previous findings, AaZAP gene expression strongly proved that AaZAP-70 was involved in immunity-like functions in mosquito. Northern blot analysis of HIP-55 mRNA expression confirmed that it is only expressed in the abdomen and haemocyte tissues; this prediction correlates 100% and a polyclonal antibody also confirmed its localization in haemocytes and the abdomen. We prepared extracts to show the cytoplasmic expression (CE) of this protein. Previous results had proven that this protein is secreted from the cytoplasm; thus, we confirmed here that the protein is a cytoplasmic adaptor protein in mosquitoes and mammalian systems. Furthermore, our polyclonal antibody against HIP-55 also demonstrated that this protein is found in haemocytes and abdomen tissues, which assumes that the protein may be involved in phagocytic-like functions. RNAi (siRNA) silencing studies were used to degrade mosquito HIP-55; however, silencing only slightly affected the HIP-55 sequence and the gene transcriptional level. To characterize this protein, we cloned 609 bp from the 1.6-kb full-length cDNA using a pET28 vector for polyclonal antibody production. Graphical abstract.
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Affiliation(s)
- M Mohiadeen Batcha
- Department of Zoology, HKRH College, Uthamapalayam, Theni District, Tamil Nadu, India.
- Post Doctoral Scientist, Institute of Tropical Medicine, National Yang Ming University, Shihpai, Taipei-112, Taiwan, Republic of China.
| | - A Sajith Ahamed
- Department of Microbiology, HKRH College, Uthamapalayam, Theni District, Tamil Nadu, India
| | - Chiung Fang Peng
- Fuga Biotechnology, Chongqing S. Rd, Zhongzheng Dist, Taipei - 100, Taiwan
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Chen EH, Hou QL, Wei DD, Dou W, Liu Z, Yang PJ, Smagghe G, Wang JJ. Tyrosine hydroxylase coordinates larval-pupal tanning and immunity in oriental fruit fly (Bactrocera dorsalis). PEST MANAGEMENT SCIENCE 2018; 74:569-578. [PMID: 28941310 DOI: 10.1002/ps.4738] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/11/2017] [Accepted: 09/16/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The oriental fruit fly Bactrocera dorsalis (Hendel), a notorious world pest infesting fruits and vegetables, has evolved a high level of resistance to many commonly used insecticides. In this study, we investigate whether tyrosine hydroxylase (TH) that is required for cuticle tanning (sclerotization and pigmentation) in many insects, could be a potential target in controlling B. dorsalis. RESULTS We cloned TH cDNA (BdTH) of B. dorsalis. The complete open reading frame of BdTH (KY911196) was 1737 bp in length, encoding a protein of 578 amino acids. Quantitative real-time PCR confirmed that BdTH was highly expressed in the epidermis of 3rd instar larvae, and its expression increased prior to pupation, suggesting a role in larval-pupal cuticle tanning. When we injected dsBdTH or 3-iodo-tyrosine (3-IT) as a TH inhibitor or fed insect diet supplemented with 3-IT, there was significant impairment of larval-pupal cuticle tanning and a severe obstacle to eclosion in adults followed by death in most. Furthermore, injection of Escherichia coli into larvae fed 3-IT resulted in 92% mortality and the expressions of four antimicrobial peptide genes were significantly downregulated. CONCLUSION These results suggest that BdTH might play a critical role in larval-pupal tanning and immunity of B. dorsalis, and could be used as a potential novel target for pest control. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Er-Hu Chen
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Qiu-Li Hou
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Dan-Dan Wei
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Wei Dou
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Zhao Liu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Pei-Jin Yang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Guy Smagghe
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Department of Crop Protection, Ghent University, Ghent, Belgium
| | - Jin-Jun Wang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
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Kumar M, Mohanty AK, Sreenivasamurthy SK, Dey G, Advani J, Pinto SM, Kumar A, Prasad TSK. Response to Blood Meal in the Fat Body of Anopheles stephensi Using Quantitative Proteomics: Toward New Vector Control Strategies Against Malaria. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2017; 21:520-530. [PMID: 28873011 DOI: 10.1089/omi.2017.0092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Malaria remains a grand challenge for disruptive innovation in global health therapeutics and diagnostics. Anopheles stephensi is one of the major vectors of malaria in Asia. Vector and transmission control are key focus areas in the fight against malaria, a field of postgenomics research where proteomics can play a substantive role. Moreover, to identify novel strategies to control the vector population, it is necessary to understand the vector life processes at a global and molecular scale. In this context, fat body is a vital organ required for vitellogenesis, vector immunity, vector physiology, and vector-parasite interaction. Given its central role in energy metabolism, vitellogenesis, and immune function, the proteome profile of the fat body and the impact of blood meal (BM) ingestion on the protein abundances of this vital organ have not been investigated so far. Therefore, using a proteomics approach, we identified the proteins expressed in the fat body of An. stephensi and their differential expression in response to BM ingestion. In all, we identified 3,218 proteins in the fat body using high-resolution mass spectrometry, of which 483 were found to be differentially expressed in response to the BM ingestion. Bioinformatics analysis of these proteins underscored their role in amino acid metabolism, vitellogenesis, lipid transport, signal peptide processing, mosquito immunity, and oxidation-reduction processes. Interestingly, we identified five novel genes, which were found to be differentially expressed upon BM ingestion. Proteins that exhibited altered expression in the present study are potential targets for vector control strategies and development of transmission blocking vaccines in the fight against malaria.
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Affiliation(s)
- Manish Kumar
- 1 Institute of Bioinformatics , Bangalore, India .,2 Manipal University , Manipal, India
| | | | | | - Gourav Dey
- 1 Institute of Bioinformatics , Bangalore, India .,2 Manipal University , Manipal, India
| | - Jayshree Advani
- 1 Institute of Bioinformatics , Bangalore, India .,2 Manipal University , Manipal, India
| | - Sneha M Pinto
- 4 YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University , Mangalore, India
| | - Ashwani Kumar
- 3 National Institute of Malaria Research (ICMR) , Panjim, India
| | - Thottethodi Subrahmanya Keshava Prasad
- 1 Institute of Bioinformatics , Bangalore, India .,4 YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University , Mangalore, India .,5 NIMHANS-IOB Proteomics and Bioinformatics Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neuro Sciences , Bangalore, India
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Du MH, Yan ZW, Hao YJ, Yan ZT, Si FL, Chen B, Qiao L. Suppression of Laccase 2 severely impairs cuticle tanning and pathogen resistance during the pupal metamorphosis of Anopheles sinensis (Diptera: Culicidae). Parasit Vectors 2017; 10:171. [PMID: 28376914 PMCID: PMC5381134 DOI: 10.1186/s13071-017-2118-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/28/2017] [Indexed: 01/15/2023] Open
Abstract
Background Phenol oxidases (POs) catalyze the oxidation of dopa and dopamine to melanin, which is crucial for cuticle formation and innate immune maintenance in insects. Although, Laccase 2, a member of the PO family, has been reported to be a requirement for melanin-mediated cuticle tanning in the development stages of some insects, whether it participates in cuticle construction and other physiological processes during the metamorphosis of mosquito pupae is unclear. Methods The association between the phenotype and the expression profile of Anopheles sinensis Laccase 2 (AsLac2) was assessed from pupation to adult eclosion. Individuals showing an expression deficiency of AsLac2 that was produced by RNAi and their phenotypic defects and physiological characterizations were compared in detail with the controls. Results During the dominant expression period, knockdown of AsLac2 in pupae caused the cuticle to be unpigmented, and produced thin and very soft cuticles, which further impeded the eclosion rate of adults as well as their fitness. Moreover, melanization immune responses in the pupae were sharply decreased, leading to poor resistance to microorganism infection. Both the high conservation among Laccase 2 homologs and a very similar genomic synteny of the neighborhood in Anopheles genus implies a conservative function in the pupal stage. Conclusions To our knowledge, this is the first study to report the serious phenotypic defects in mosquito pupae caused by the dysfunction of Laccase 2. Our findings strongly suggest that Laccase 2 is crucial for Anopheles cuticle construction and melanization immune responses to pathogen infections during pupal metamorphosis. This irreplaceability provides valuable information on the application of Lacccase 2 and/or other key genes in the melanin metabolism pathway for developing mosquito control strategies. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2118-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ming-Hui Du
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology; College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Zheng-Wen Yan
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology; College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - You-Jin Hao
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology; College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Zhen-Tian Yan
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology; College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Feng-Ling Si
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology; College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Bin Chen
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology; College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China.
| | - Liang Qiao
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology; College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China.
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Simonet P, Gaget K, Parisot N, Duport G, Rey M, Febvay G, Charles H, Callaerts P, Colella S, Calevro F. Disruption of phenylalanine hydroxylase reduces adult lifespan and fecundity, and impairs embryonic development in parthenogenetic pea aphids. Sci Rep 2016; 6:34321. [PMID: 27694983 PMCID: PMC5046115 DOI: 10.1038/srep34321] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 09/12/2016] [Indexed: 11/11/2022] Open
Abstract
Phenylalanine hydroxylase (PAH) is a key tyrosine-biosynthetic enzyme involved in neurological and melanin-associated physiological processes. Despite extensive investigations in holometabolous insects, a PAH contribution to insect embryonic development has never been demonstrated. Here, we have characterized, for the first time, the PAH gene in a hemimetabolous insect, the aphid Acyrthosiphon pisum. Phylogenetic and sequence analyses confirmed that ApPAH is closely related to metazoan PAH, exhibiting the typical ACT regulatory and catalytic domains. Temporal expression patterns suggest that ApPAH has an important role in aphid developmental physiology, its mRNA levels peaking at the end of embryonic development. We used parental dsApPAH treatment to generate successful knockdown in aphid embryos and to study its developmental role. ApPAH inactivation shortens the adult aphid lifespan and considerably affects fecundity by diminishing the number of nymphs laid and impairing embryonic development, with newborn nymphs exhibiting severe morphological defects. Using single nymph HPLC analyses, we demonstrated a significant tyrosine deficiency and a consistent accumulation of the upstream tyrosine precursor, phenylalanine, in defective nymphs, thus confirming the RNAi-mediated disruption of PAH activity. This study provides first insights into the role of PAH in hemimetabolous insects and demonstrates that this metabolic gene is essential for insect embryonic development.
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Affiliation(s)
- Pierre Simonet
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Karen Gaget
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Nicolas Parisot
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Gabrielle Duport
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Marjolaine Rey
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Gérard Febvay
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Hubert Charles
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Patrick Callaerts
- KU Leuven, University of Leuven, Department of Human Genetics, Laboratory of Behavioral and Developmental Genetics, B-3000, Leuven, Belgium
- VIB Center for the Biology of Disease, B-3000, Leuven, Belgium
| | - Stefano Colella
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
| | - Federica Calevro
- Univ Lyon, INSA-Lyon, INRA, BF2I, UMR0203, F-69621, Villeurbanne, France
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6
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Qiao L, Du M, Liang X, Hao Y, He X, Si F, Mei T, Chen B. Tyrosine Hydroxylase is crucial for maintaining pupal tanning and immunity in Anopheles sinensis. Sci Rep 2016; 6:29835. [PMID: 27416870 PMCID: PMC4945905 DOI: 10.1038/srep29835] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/31/2016] [Indexed: 11/09/2022] Open
Abstract
Tyrosine hydroxylase (TH), the initial enzyme in the melanin pathway, catalyzes tyrosine conversion into Dopa. Although expression and regulation of TH have been shown to affect cuticle pigmentation in insects, no direct functional studies to date have focused on the specific physiological processes involving the enzyme during mosquito development. In the current study, silencing of AsTH during the time period of continuous high expression in Anopheles sinensis pupae led to significant impairment of cuticle tanning and thickness, imposing a severe obstacle to eclosion in adults. Meanwhile, deficiency of melanin in interference individuals led to suppression of melanization, compared to control individuals. Consequently, the ability to defend exogenous microorganisms declined sharply. Accompanying down-regulation of the basal expression of five antimicrobial peptide genes resulted in further significant weakening of immunity. TH homologs as well as the composition of upstream transcription factor binding sites at the pupal stage are highly conserved in the Anopheles genus, implying that the TH-mediated functions are crucial in Anopheles. The collective evidence strongly suggests that TH is essential for Anopheles pupae tanning and immunity and provides a reference for further studies to validate the utility of the key genes involved in the melanization pathway in controlling mosquito development.
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Affiliation(s)
- Liang Qiao
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Minghui Du
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Xin Liang
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Youjin Hao
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Xiu He
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Fengling Si
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Ting Mei
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Bin Chen
- Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
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Hillyer JF, Strand MR. Mosquito hemocyte-mediated immune responses. CURRENT OPINION IN INSECT SCIENCE 2014; 3:14-21. [PMID: 25309850 PMCID: PMC4190037 DOI: 10.1016/j.cois.2014.07.002] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hemocytes are a key component of the mosquito immune system that kill pathogens via phagocytic, lytic and melanization pathways. Individual mosquitoes contain between 500 and 4,000 hemocytes, which are divided into three populations named granulocytes, oenocytoids and prohemocytes. Hemocytes can also be divided by their anatomical location with 75% of hemocytes circulating in the hemocoel (circulating hemocytes) and 25% of hemocytes attaching themselves to tissues (sessile hemocytes). Greater than 85% of the hemocytes in adult mosquitoes are granulocytes, which primarily kill pathogens by phagocytosis or lysis. Oenocytoids, on the other hand, are the major producers of the enzymes required for melanization while prohemocytes are small cells that participate in phagocytosis. Both circulating and sessile hemocytes engage in defense against pathogens. The circulatory system of mosquitoes also interacts with hemocytes and facilitates elimination of potential pathogens that enter the hemocoel.
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Affiliation(s)
- Julián F. Hillyer
- Department of Biological Sciences and Institute for Global Health, Vanderbilt University, Nashville, TN, USA
| | - Michael R. Strand
- Department of Entomology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
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Bartholomay LC. Infection barriers and responses in mosquito-filarial worm interactions. CURRENT OPINION IN INSECT SCIENCE 2014; 3:37-42. [PMID: 32846673 DOI: 10.1016/j.cois.2014.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/08/2014] [Accepted: 08/08/2014] [Indexed: 06/11/2023]
Abstract
As a function of size, migration trajectory through the body and developmental site, filarial worm parasites inflict significant damage on the mosquito host. Some mosquitoes are equipped with physical and physiological barriers that confer a refractory state to parasite infection. In a susceptible host, parasites migrate to a developmental site and achieve an intracellular existence; during this process, worms elicit canonical mosquito immune response elements, particularly melanization and antimicrobial peptide (AMP) production. It is clear now that the response to infection also involves mitigating stress and manipulation of host cell machinery to delay necrosis. This review focuses on mechanisms of refractoriness and resistance to Brugia malayi, Brugia pahangi, and Dirofilaria immitis, with emphasis on infection in the mosquito, Aedes aegypti.
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Affiliation(s)
- Lyric C Bartholomay
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States.
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Fuchs S, Behrends V, Bundy JG, Crisanti A, Nolan T. Phenylalanine metabolism regulates reproduction and parasite melanization in the malaria mosquito. PLoS One 2014; 9:e84865. [PMID: 24409310 PMCID: PMC3883676 DOI: 10.1371/journal.pone.0084865] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/20/2013] [Indexed: 11/25/2022] Open
Abstract
The blood meal of the female malaria mosquito is a pre-requisite to egg production and also represents the transmission route for the malaria parasite. The proper and rapid assimilation of proteins and nutrients in the blood meal creates a significant metabolic challenge for the mosquito. To better understand this process we generated a global profile of metabolite changes in response to blood meal of Anopheles gambiae, using Gas Chromatography-Mass Spectrometry (GC-MS). To disrupt a key pathway of amino acid metabolism we silenced the gene phenylalanine hydroxylase (PAH) involved in the conversion of the amino acid phenylalanine into tyrosine. We observed increased levels of phenylalanine and the potentially toxic metabolites phenylpyruvate and phenyllactate as well as a reduction in the amount of tyrosine available for melanin synthesis. This in turn resulted in a significant impairment of the melanotic encapsulation response against the rodent malaria parasite Plasmodium berghei. Furthermore silencing of PAH resulted in a significant impairment of mosquito fertility associated with reduction of laid eggs, retarded vitellogenesis and impaired melanisation of the chorion. Carbidopa, an inhibitor of the downstream enzyme DOPA decarboxylase that coverts DOPA into dopamine, produced similar effects on egg melanization and hatching rate suggesting that egg chorion maturation is mainly regulated via dopamine. This study sheds new light on the role of amino acid metabolism in regulating reproduction and immunity.
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Affiliation(s)
- Silke Fuchs
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Volker Behrends
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Jacob G. Bundy
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Andrea Crisanti
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Tony Nolan
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail:
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10
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Chen P, Li L, Wang J, Li H, Li Y, Lv Y, Lu C. BmPAH catalyzes the initial melanin biosynthetic step in Bombyx mori. PLoS One 2013; 8:e71984. [PMID: 23991017 PMCID: PMC3753331 DOI: 10.1371/journal.pone.0071984] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Accepted: 07/06/2013] [Indexed: 11/19/2022] Open
Abstract
Pigmentation during insect development is a primal adaptive requirement. In the silkworm, melanin is the primary component of larval pigments. The rate limiting substrate in melanin synthesis is tyrosine, which is converted from phenylalanine by the rate-limiting enzyme phenylalanine hydroxylase (PAH). While the role of tyrosine, derived from phenylalanine, in the synthesis of fiber proteins has long been known, the role of PAH in melanin synthesis is still unknown in silkworm. To define the importance of PAH, we cloned the cDNA sequence of BmPAH and expressed its complete coding sequence using the Bac-to-Bac baculovirus expression system. Purified recombinant protein had high PAH activity, some tryptophan hydroxylase activity, but no tyrosine hydroxylase activity, which are typical properties of PAH in invertebrates. Because melanin synthesis is most robust during the embryonic stage and larval integument recoloring stage, we injected BmPAH dsRNA into silkworm eggs and observed that decreasing BmPAH mRNA reduced neonatal larval tyrosine and caused insect coloration to fail. In vitro cultures and injection of 4th instar larval integuments with PAH inhibitor revealed that PAH activity was essential for larval marking coloration. These data show that BmPAH is necessary for melanin synthesis and we propose that conversion of phenylalanine to tyrosine by PAH is the first step in the melanin biosynthetic pathway in the silkworm.
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Affiliation(s)
- Ping Chen
- State Key Laboratory of Silkworm Genome Biology and College of Biotechnology, Southwest University, Chongqing, China ; College of Biotechnology, Southwest University, Chongqing, China
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Waisberg M, Vickers BK, Yager SB, Lin CK, Pierce SK. Testing in mice the hypothesis that melanin is protective in malaria infections. PLoS One 2012; 7:e29493. [PMID: 22242171 PMCID: PMC3252320 DOI: 10.1371/journal.pone.0029493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 11/29/2011] [Indexed: 01/22/2023] Open
Abstract
Malaria has had the largest impact of any infectious disease on shaping the human genome, exerting enormous selective pressure on genes that improve survival in severe malaria infections. Modern humans originated in Africa and lost skin melanization as they migrated to temperate regions of the globe. Although it is well documented that loss of melanization improved cutaneous Vitamin D synthesis, melanin plays an evolutionary ancient role in insect immunity to malaria and in some instances melanin has been implicated to play an immunoregulatory role in vertebrates. Thus, we tested the hypothesis that melanization may be protective in malaria infections using mouse models. Congenic C57BL/6 mice that differed only in the gene encoding tyrosinase, a key enzyme in the synthesis of melanin, showed no difference in the clinical course of infection by Plasmodium yoelii 17XL, that causes severe anemia, Plasmodium berghei ANKA, that causes severe cerebral malaria or Plasmodium chabaudi AS that causes uncomplicated chronic disease. Moreover, neither genetic deficiencies in vitamin D synthesis nor vitamin D supplementation had an effect on survival in cerebral malaria. Taken together, these results indicate that neither melanin nor vitamin D production improve survival in severe malaria.
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Affiliation(s)
- Michael Waisberg
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail: (MW); (SKP)
| | - Brandi K. Vickers
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Stephanie B. Yager
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Christina K. Lin
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Susan K. Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail: (MW); (SKP)
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Zhou Z, Wang L, Wang M, Zhang H, Wu T, Qiu L, Song L. Scallop phenylalanine hydroxylase implicates in immune response and can be induced by human TNF-α. FISH & SHELLFISH IMMUNOLOGY 2011; 31:856-863. [PMID: 21839840 DOI: 10.1016/j.fsi.2011.07.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 07/21/2011] [Accepted: 07/21/2011] [Indexed: 05/31/2023]
Abstract
Phenylalanine hydroxylase (PAH) is an important metabolic enzyme of aromatic amino acids, which is responsible for the irreversible oxidation of phenylalanine to tyrosine. In the present study, the full-length cDNA encoding PAH from Chlamys farreri (designated CfPAH) was cloned by using rapid amplification of cDNA ends (RACE) approaches and expression sequence tag (EST) analysis. The open reading frame of CfPAH encoded a polypeptide of 460 amino acids, and its sequence shared 64.4-74.2% similarity with those of PAHs from other animals. There were an N-terminal regulatory ACT domain and a C-terminal catalytic Biopterin_H domain in the deduced CfPAH protein. The mRNA transcripts of CfPAH could be detected in all the tested tissues, including adductor muscle, mantle, gill, gonad, haemocytes and hepatopancreas. And its expression level in haemocytes was increased significantly during 3-48 h after bacteria Vibrio anguillarum challenge with the highest level (9.1-fold, P < 0.05) at 24 h. Furthermore, the mRNA expression of CfPAH in haemocytes also increased significantly to 2.6-fold (P < 0.05) at 4 h and 3.3-fold (P < 0.05) at 6 h after the stimulation of 50.0 ng mL(-1) human TNF-α. The cDNA fragment encoding the mature peptide of CfPAH was recombined and expressed in the prokaryotic expression system, and 1 mg recombinant CfPAH protein (rCfPAH) could catalyze the conversion of 192.23 ± 32.35 nmol phenylalanine to tyrosine within 1 min (nmol min(-1) mg(-1) protein) in vitro. These results indicated collectively that CfPAH, as a homologue of phenylalanine hydroxylase in scallop C. farreri, could be induced by cytokine and involved in the immunomodulation of scallops by supplying the starting material tyrosine for the synthesis of melanin and catecholamines.
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Affiliation(s)
- Zhi Zhou
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
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13
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Abstract
Throughout their lifetime, mosquitoes are exposed to pathogens during feeding, through breaks in their cuticle and following pathogen-driven cuticular degradation. To resist infection, mosquitoes mount innate cellular and humoral immune responses that are elicited within minutes of exposure and can lead to pathogen death via three broadly defined mechanisms: lysis, melanization and hemocyte-mediated phagocytosis. This chapter reviews our current understanding of the mosquito immune system, with an emphasis on the physical barriers that prevent pathogens from entering the body, the organs and tissues that regulate immune responses and the mechanistic and molecular bases of immunity.
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Affiliation(s)
- Julián F Hillyer
- Department of Biological Sciences, Institute for Global Health, Vanderbilt University, Nashville, Tennessee, USA.
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14
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Hillyer JF, Estévez-Lao TY. Nitric oxide is an essential component of the hemocyte-mediated mosquito immune response against bacteria. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2010; 34:141-149. [PMID: 19733588 DOI: 10.1016/j.dci.2009.08.014] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 08/29/2009] [Accepted: 08/29/2009] [Indexed: 05/28/2023]
Abstract
Nitric oxide is a signaling and immune effector molecule synthesized by the enzyme nitric oxide synthase. In mosquitoes, nitric oxide functions as a parasite antagonist in the midgut but little is known about its function in the hemocoel. Here, we characterized the temporal and spatial expression of the Anopheles gambiae nitric oxide synthase gene and explored the role nitric oxide plays in the antibacterial response in the mosquito hemocoel. Quantitative PCR and Western blot analyses showed that nitric oxide synthase is expressed in hemocytes and fat body, and is upregulated in response to systemic infection with Escherichia coli and Micrococcus luteus. Diaphorase staining and immunofluorescence showed that nitric oxide synthase is abundant in the granulocyte subpopulation of hemocytes, and both the staining intensity and the percentage of cells that stain for nitric oxide synthase significantly increase after a bacterial challenge. When nitric oxide production was inhibited, the mosquito's ability to kill E. coli was significantly reduced. Accordingly, inhibiting nitric oxide production increased the mortality rate of mosquitoes with systemic E. coli infections. Taken altogether, these data show that nitric oxide is a crucial player in the antibacterial immune response in the mosquito hemocoel.
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Affiliation(s)
- Julián F Hillyer
- Department of Biological Sciences and Institute for Global Health, Vanderbilt University, VU Station B 35-1634, Nashville, TN 37235-1634, USA.
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15
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Increase in the substrate availability decreases phenoloxidase activity in the autumnal moth, Epirrita autumnata. CHEMOECOLOGY 2009. [DOI: 10.1007/s00049-009-0029-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Liu F, Ling E, Wu S. Gene expression profiling during early response to injury and microbial challenges in the silkworm, Bombyx mori. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2009; 72:16-33. [PMID: 19557735 DOI: 10.1002/arch.20320] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
To identify Bombyx mori genes involved in the early response to injury and microbial challenge, we performed genome-wide gene expression-profiling experiments using oligonucleotide DNA microarrays. Of approximately 23,000 genes examined, 465 displayed changes in mRNA expression levels. Of these, 306 were induced and 159 were repressed in response to injury (injection with phosphate buffer saline) or challenges by Gram-negative (Serratia marcescens), Gram-positive bacteria (Staphylococcus aureus), or fungus (Beauveria bassiana). Many of these differentially expressed genes can be assigned to specific functional groups of the innate immune response, including recognition, signaling, melanization and coagulation, and antimicrobial peptides. Seventeen percent of differentially expressed genes encode proteins with no obvious similarity to known functional domains. Of particular interest is a member of the juvenile hormone-binding protein family, which was highly induced by both injury and microbial challenges. The possible role of juvenile hormone in innate immunity is discussed.
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Affiliation(s)
- Fei Liu
- Research Center for Insect Science, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences Graduate School, Shanghai, People's Republic of China
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17
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Genome-wide transcriptomic profiling of Anopheles gambiae hemocytes reveals pathogen-specific signatures upon bacterial challenge and Plasmodium berghei infection. BMC Genomics 2009; 10:257. [PMID: 19500340 PMCID: PMC2703655 DOI: 10.1186/1471-2164-10-257] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 06/05/2009] [Indexed: 12/21/2022] Open
Abstract
Background The mosquito Anopheles gambiae is a major vector of human malaria. Increasing evidence indicates that blood cells (hemocytes) comprise an essential arm of the mosquito innate immune response against both bacteria and malaria parasites. To further characterize the role of hemocytes in mosquito immunity, we undertook the first genome-wide transcriptomic analyses of adult female An. gambiae hemocytes following infection by two species of bacteria and a malaria parasite. Results We identified 4047 genes expressed in hemocytes, using An. gambiae genome-wide microarrays. While 279 transcripts were significantly enriched in hemocytes relative to whole adult female mosquitoes, 959 transcripts exhibited immune challenge-related regulation. The global transcriptomic responses of hemocytes to challenge with different species of bacteria and/or different stages of malaria parasite infection revealed discrete, minimally overlapping, pathogen-specific signatures of infection-responsive gene expression; 105 of these represented putative immunity-related genes including anti-Plasmodium factors. Of particular interest was the specific co-regulation of various members of the Imd and JNK immune signaling pathways during malaria parasite invasion of the mosquito midgut epithelium. Conclusion Our genome-wide transcriptomic analysis of adult mosquito hemocytes reveals pathogen-specific signatures of gene regulation and identifies several novel candidate genes for future functional studies.
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18
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Paskewitz SM, Andreev O. Silencing the genes for dopa decarboxylase or dopachrome conversion enzyme reduces melanization of foreign targets in Anopheles gambiae. Comp Biochem Physiol B Biochem Mol Biol 2008; 150:403-8. [PMID: 18534885 DOI: 10.1016/j.cbpb.2008.04.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 04/23/2008] [Accepted: 04/24/2008] [Indexed: 11/16/2022]
Abstract
The production of melanin is a complex biochemical process in which several enzymes may play a role. Although phenoloxidase and serine proteases are clearly key components, the activity of other enzymes, including dopa decarboxylase and dopachrome conversion enzyme may also be required. We tested the effect of knockdown of gene expression for these two enzymes on melanization of abiotic targets in the mosquito, Anopheles gambiae. Knockdown of dopa decarboxylase and dopachrome conversion enzyme resulted in a significant reduction of melanization of Sephadex beads at 24 h after injection. Knockdown of a third enzyme, phenylalanine hydroxylase, which is involved in endogenous production of tyrosine, had no effect on bead melanization. Quantitative analysis of gene expression demonstrated significant upregulation of phenylalanine hydroxylase, but not the other two genes, following injection.
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Affiliation(s)
- Susan M Paskewitz
- Department of Entomology, University of Wisconsin, Madison, Wisconsin, USA.
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19
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Bartholomay LC, Mayhew GF, Fuchs JF, Rocheleau TA, Erickson SM, Aliota MT, Christensen BM. Profiling infection responses in the haemocytes of the mosquito, Aedes aegypti. INSECT MOLECULAR BIOLOGY 2007; 16:761-776. [PMID: 18093005 DOI: 10.1111/j.1365-2583.2007.00773.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Pathogens that infect and/or are transmitted by mosquitoes typically are exposed to the body cavity, and to haemocytes circulating therein, during development or dissemination. Aedes aegypti haemocytes produce a range of immune response-related gene products, and an endpoint response of phagocytosis and/or melanization that is temporally and structurally distinct for the invading pathogen. Expressed sequence tags were generated from haemocyte libraries and then used to design oligonucleotide microarrays. Arrays were screened with haemocyte material collected 1-, 8- and 24-h post-inoculation with Escherichia coli or Micrococcus luteus bacteria. Data from these studies support the discovery of novel immune response-activated genes, provide an expanded understanding of antimicrobial peptide biology and highlight the coordination of immune factors that leads to an endpoint response.
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Affiliation(s)
- L C Bartholomay
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
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20
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Hillyer JF, Schmidt SL, Fuchs JF, Boyle JP, Christensen BM. Age-associated mortality in immune challenged mosquitoes (Aedes aegypti) correlates with a decrease in haemocyte numbers. Cell Microbiol 2005; 7:39-51. [PMID: 15617522 DOI: 10.1111/j.1462-5822.2004.00430.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mosquitoes vector pathogens. One aspect that has been overlooked in mosquito-pathogen relationships is the effect of host age on immune competence. Here, we show that there is age-associated mortality following immune challenge with Escherichia coli. This mortality correlates with a decrease in haemocyte numbers (blood cells) and a decreased ability to kill E. coli. Although the number of haemocytes decreases, the available haemocytes retain their phagocytic ability regardless of age, and we estimate that individual granulocytes can phagocytose approximately 1500 E. coli. Moreover, transcription profiles for cecropin, defensin and gambicin in E. coli challenged mosquitoes do not change with age, indicating that the increased susceptibility is not attributed to fewer humoral antimicrobial peptides. These results suggest that a contributing factor for the age-associated mortality is the decrease in circulating haemocytes, which reduces the overall phagocytic capacity of mosquitoes. To our knowledge, this is the first report detailing an age-associated decline in the immunological capabilities of mosquitoes following challenge with an infectious agent. These data also call for caution in the analysis and interpretation of experimental results when mosquito age has not been closely monitored. Lastly, a model for haemocyte function is presented.
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Affiliation(s)
- Julián F Hillyer
- Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, 1656 Linden Drive, Madison, WI 53706, USA
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21
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Abstract
The production and deposition of melanin pigments on invading pathogens and parasites represents a unique, innate immune response in the phylum Arthropoda. This immune response has started to receive considerable attention because of the potential to exploit this mechanism to control mosquito-borne diseases. In this article, we summarize knowledge about this complex biochemistry, the use of melanin biosynthesis in diverse physiological processes and the gaps in knowledge that must be addressed if this immune process is to be manipulated in genetic-based control strategies.
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Affiliation(s)
- Bruce M Christensen
- Department of Animal Health and Biomedical Sciences, 1656 Linden Drive, University of Wisconsin, Madison, WI 53706, USA.
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22
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Nappi AJ, Frey F, Carton Y. Drosophila serpin 27A is a likely target for immune suppression of the blood cell-mediated melanotic encapsulation response. JOURNAL OF INSECT PHYSIOLOGY 2005; 51:197-205. [PMID: 15749104 DOI: 10.1016/j.jinsphys.2004.10.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Revised: 10/06/2004] [Accepted: 10/07/2004] [Indexed: 05/24/2023]
Abstract
Avirulent strains of the endoparasitoid Leptopilina boulardi succumb to a blood cell-mediated melanotic encapsulation response in host larvae of Drosophila melanogaster. Virulent wasp strains effectively abrogate the cellular response with substances introduced into the host that specifically target and effectively suppress one or more immune signaling pathways, including elements that control phenoloxidase-mediated melanotic encapsulation. The present study implicates involvement of the Drosophila Toll pathway in cellular innate immunity by regulating the serine protease inhibitor Serpin 27A (Spn27A), which normally functions as a negative regulator of phenoloxidase. The introduction of Spn27A into normally highly immune competent D. melanogaster larvae significantly reduced their ability to form melanotic capsules around eggs of L. boulardi. This study confirms the role of Spn27A in the melanization cascade and establishes that this pathway and associated blood cell responses can be activated by parasitization. The activation of phenoloxidase and the site-specific localization of the ensuing melanotic response are such critical components of the blood cell response that Spn27A and the signaling elements mediating its activity are likely to represent prime targets for immune suppression by L. boulardi.
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Affiliation(s)
- A J Nappi
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, 1556 Linden Drive, Wisconsin 53706, USA.
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23
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Cong R, Sun W, Liu G, Fan T, Meng X, Yang L, Zhu L. Purification and characterization of phenoloxidase from clam Ruditapes philippinarum. FISH & SHELLFISH IMMUNOLOGY 2005; 18:61-70. [PMID: 15450969 DOI: 10.1016/j.fsi.2004.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Accepted: 06/01/2004] [Indexed: 05/24/2023]
Abstract
Using L-dihydroxyphenylalanine (L-DOPA) as a specific substrate, phenoloxidase (PO) from clam (Ruditapes philippinarum) was purified by Q Sepharose Fast Flow ion-exchange chromatography and Sephacryl S-100 gel-filtration, and characterized biochemically and enzymatically in this study. The molecular mass of PO in SDS-PAGE is about 76.9 kDa, and the prophenoloxidase (proPO) molecule, isolated as a monomeric protein, is 84.1 kDa. The PO molecule had a high oxidative activity, and the proPO molecule had almost no oxidative activity. The PO activity was optimal at pH 7.0 and temperature of 40 degrees C. The Km value of the PO for L-DOPA was 2.2 mmol l(-1). The PO was extremely sensitive to benzoic acid and sodium sulfite, very sensitive to citric acid, thio urea, 1-phenyl-2-thiourea and cysteine, but not sensitive to ascorbic acid. Combined with its specific enzyme activity on tyrosine and L-DOPA, it can be concluded that the Ruditapes PO is probably a kind of tyrosinase-type phenoloxidase. The PO activity was strongly inhibited by ethylenediaminetetraacetic acid (EDTA), diethyldithiocarbamate (DETC), Zn2+, Ca2+ and Cu2+, as well as by Mg2+. The results with EDTA, DETC, and some metal ions, combined with the perfect recovery effect of Cu2+ on DETC-inhibited PO activity, indicate that Ruditapes PO is most probably a copper-containing metalloenzyme.
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Affiliation(s)
- Rishan Cong
- Department of Marine Biology, Division of Life Science and Technology, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China.
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Infanger LC, Rocheleau TA, Bartholomay LC, Johnson JK, Fuchs J, Higgs S, Chen CC, Christensen BM. The role of phenylalanine hydroxylase in melanotic encapsulation of filarial worms in two species of mosquitoes. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2004; 34:1329-1338. [PMID: 15544946 DOI: 10.1016/j.ibmb.2004.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 09/15/2004] [Accepted: 09/24/2004] [Indexed: 05/24/2023]
Abstract
Melanin formation has a significant influence on mosquito vector competence by limiting the development of metazoan parasites. Tyrosine, the rate-limiting substrate of melanin production, can be obtained exogenously or derived from phenylalanine by phenylalanine hydroxylase (PAH). The characteristics of this defense mechanism, such as temporal expression of constituent enzymes involved in the biosynthetic pathway, can vary considerably between mosquito species. We investigated the functional role of PAH in the melanotic encapsulation response in Aedes aegypti and Armigeres subalbatus, two mosquito species with markedly different melanization responses. We used double-stranded RNA (dsRNA) to knock down PAH and observed the phenotypic effects on melanin formation. PAH transcripts were dramatically reduced in both mosquito species after gene knock down. The abundance of PAH proteins was decreased in gene knockdown mosquitoes that were inoculated with Dirofilaria immitis microfilariae (mf) as compared to inoculation controls. A significant reduction of mf melanization also was observed in these knockdown mosquitoes as compared to inoculation controls. Our data suggest that PAH is required for a fully functional melanotic encapsulation response in both mosquito vectors.
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Affiliation(s)
- Li-Chun Infanger
- Department of Animal Health & Biomedical Sciences, University of Wisconsin-Madison, 1656 Linden Dr., Madison, WI 53706, USA
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25
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Bartholomay LC, Cho WL, Rocheleau TA, Boyle JP, Beck ET, Fuchs JF, Liss P, Rusch M, Butler KM, Wu RCC, Lin SP, Kuo HY, Tsao IY, Huang CY, Liu TT, Hsiao KJ, Tsai SF, Yang UC, Nappi AJ, Perna NT, Chen CC, Christensen BM. Description of the transcriptomes of immune response-activated hemocytes from the mosquito vectors Aedes aegypti and Armigeres subalbatus. Infect Immun 2004; 72:4114-26. [PMID: 15213157 PMCID: PMC427405 DOI: 10.1128/iai.72.7.4114-4126.2004] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 03/05/2004] [Accepted: 03/21/2004] [Indexed: 01/04/2023] Open
Abstract
Mosquito-borne diseases, including dengue, malaria, and lymphatic filariasis, exact a devastating toll on global health and economics, killing or debilitating millions every year (54). Mosquito innate immune responses are at the forefront of concerted research efforts aimed at defining potential target genes that could be manipulated to engineer pathogen resistance in vector populations. We aimed to describe the pivotal role that circulating blood cells (called hemocytes) play in immunity by generating a total of 11,952 Aedes aegypti and 12,790 Armigeres subalbatus expressed sequence tag (EST) sequences from immune response-activated hemocyte libraries. These ESTs collapsed into 2,686 and 2,107 EST clusters, respectively. The clusters were used to adapt the web-based interface for annotating bacterial genomes called A Systematic Annotation Package for Community Analysis of Genomes (ASAP) for analysis of ESTs. Each cluster was categorically characterized and annotated in ASAP based on sequence similarity to five sequence databases. The sequence data and annotations can be viewed in ASAP at https://asap.ahabs.wisc.edu/annotation/php/ASAP1.htm. The data presented here represent the results of the first high-throughput in vivo analysis of the transcriptome of immunocytes from an invertebrate. Among the sequences are those for numerous immunity-related genes, many of which parallel those employed in vertebrate innate immunity, that have never been described for these mosquitoes. The sequences and annotations presented in this paper have been submitted to GenBank under accession numbers AY 431103 to AY 433788 (Aedes aegypti) and AY 439334 to AY 441440 (Armigeres subalbatus).
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Affiliation(s)
- Lyric C Bartholomay
- Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, 1656 Linden Drive, Madison, WI 53706, USA
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Bartholomay LC, Fuchs JF, Cheng LL, Beck ET, Vizioli J, Lowenberger C, Christensen BM. Reassessing the role of defensin in the innate immune response of the mosquito, Aedes aegypti. INSECT MOLECULAR BIOLOGY 2004; 13:125-132. [PMID: 15056359 DOI: 10.1111/j.0962-1075.2004.00467.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Defensin is the predominant inducible immune peptide in Aedes aegypti. In spite of its activity against Gram-positive bacteria in vitro, defensin expression is detected in mosquitoes inoculated with Gram-positive or negative bacteria, or with filarial worms. Defensin transcription and expression are dependent upon bacterial dose; however, translation is inconsistent with transcription because peptide is detectable only in mosquitoes inoculated with large doses. In vitro translation assays provide further evidence for post-transcriptional regulation of defensin. Clearance assays show that a majority of bacteria are cleared before defensin is detected. In gene silencing experiments, no significant difference in mortality was observed between defensin-deficient and control mosquitoes after bacteria inoculation. These studies suggest that defensin may have an alternative function in mosquito immunity.
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Affiliation(s)
- L C Bartholomay
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, WI 53706, USA
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Guedes SDM, Vitorino R, Tomer K, Domingues MRM, Correia AJF, Amado F, Domingues P. Drosophila melanogaster larval hemolymph protein mapping. Biochem Biophys Res Commun 2004; 312:545-54. [PMID: 14680800 DOI: 10.1016/j.bbrc.2003.10.156] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Indexed: 11/20/2022]
Abstract
With the completion of the genome sequence of Drosophila melanogaster the importance of constructing a proteome map is to be considered. Therefore, with the application of recent advances in proteomic analysis approaches, a protein map of D. melanogaster larvae hemolymph proteins was obtained using 2-DE in the range of pH 3-10. After Coomassie colloidal detection of 289 spots, a total of 105 were excised from the gel and digested with trypsin. Identification was done based on a combination of MALDI-TOF/TOF MS and MS/MS spectra. The 99 proteins identified using this approach include a large number of metabolic enzymes, translational apparatus components, and structural proteins. Among these we emphasize the identification of proteins with molecular chaperone properties (heat shock proteins and PPIases) and protein spots involved in defense responses such as antioxidant and immunological defense mechanisms (thioredoxin, prophenoloxidase, and serine proteases), as well as in signal transduction pathways.
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