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Khoshdel Nezamiha F, Imani S, Arabi Mianroodi R, Tirgari S, Shahbazzadeh D. OdTx12/GNA, a chimeric variant of a β excitatory toxin from Odontobuthus doriae, reveals oral toxicity towards Locusta migratoria and Tenebrio molitor. Toxicon 2021; 202:13-19. [PMID: 34537212 DOI: 10.1016/j.toxicon.2021.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/26/2021] [Accepted: 09/08/2021] [Indexed: 11/18/2022]
Abstract
OdTx12, a beta excitatory toxin from Odontobothus doriae had previously been identified and characterized. It had been shown that OdTx12 causes significant lethal effects on insects by injection but does not show any toxicity on mice. Due to the natural ineffectiveness of scorpion toxins to act as oral toxins, OdTx12 was fused to Galanthus nivalis agglutinin (GNA), a protein with the potential to cross the insect gut. The sequence of OdTx12/GNA gene was chemically synthesized, cloned in Escherichia coli, and expressed. The effect of the purified fusion protein (OdTx12/GNA) was assessed on the insect and mammalian cell lines, insect larvae and mice. Toxicity assay on insect cell culture (SF9 cell line) showed comparable toxicity between OdTx12 and OdTx12/GNA (LD50 of 0.0030 and 0.0048 μM, respectively). Also very similar mortality rates were observed by injecting OdTx12 and OdTx12/GNA to Locusta migratoria and Tenebrio molitor. Oral administration of OdTx12/GNA, after five days of feeding, resulted in 96.6% and 98.3% mortality of L. migratoria and T. molitor larvae with an LC50 of 0.69 and 0.43 nmol/g of insect food, respectively, while OdTx12 alone did not cause any toxic effects on the larvae orally, suggesting the role of GNA in delivering the toxin to the insect's haemolymph. No toxicity or mortality was observed after toxicity testing of OdTx12/GNA on a mammalian cell line (HEP-2) or any mortality in vivo, by testing the protein in the laboratory mouse. Herein, we demonstrated that the fusion protein OdTx12/GNA could be considered an effective toxin for the biological control of insects.
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Affiliation(s)
| | - Sohrab Imani
- Department of Plant Protection, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Reza Arabi Mianroodi
- R&D Department, Production and Research Complex, Pasteur Institute of Iran, Tehran, Iran.
| | | | - Delavar Shahbazzadeh
- Department of Medical Biotechnology of Iran, Venom and Therapeutic Biomolecules Lab, Institute Pasteur of Iran, Tehran, Iran
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Das B, Saviola AJ, Mukherjee AK. Biochemical and Proteomic Characterization, and Pharmacological Insights of Indian Red Scorpion Venom Toxins. Front Pharmacol 2021; 12:710680. [PMID: 34650430 PMCID: PMC8505525 DOI: 10.3389/fphar.2021.710680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/16/2021] [Indexed: 12/16/2022] Open
Abstract
The Indian red scorpion (Mesobuthus tamulus) is one of the world's deadliest scorpions, with stings representing a life-threatening medical emergency. This species is distributed throughout the Indian sub-continent, including eastern Pakistan, eastern Nepal, and Sri Lanka. In India, Indian red scorpions are broadly distributed in western Maharashtra, Saurashtra, Kerala, Andhra Pradesh, Tamil Nadu, and Karnataka; however, fatal envenomations have been recorded primarily in the Konkan region of Maharashtra. The Indian red scorpion venom proteome comprises 110 proteins belonging to 13 venom protein families. The significant pharmacological activity is predominantly caused by the low molecular mass non-enzymatic Na+ and K+ ion channel toxins. Other minor toxins comprise 15.6% of the total venom proteome. Indian red scorpion stings induce the release of catecholamine, which leads to pathophysiological abnormalities in the victim. A strong correlation has been observed between venom proteome composition and local (swelling, redness, heat, and regional lymph node involvement) and systemic (tachycardia, mydriasis, hyperglycemia, hypertension, toxic myocarditis, cardiac failure, and pulmonary edema) manifestations. Immediate administration of antivenom is the preferred treatment for Indian red scorpion stings. However, scorpion-specific antivenoms have exhibited poor immunorecognition and neutralization of the low molecular mass toxins. The proteomic analysis also suggests that Indian red scorpion venom is a rich source of pharmacologically active molecules that may be envisaged as drug prototypes. The following review summarizes the progress made towards understanding the venom proteome of the Indian red scorpion and addresses the current understanding of the pathophysiology associated with its sting.
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Affiliation(s)
- Bhabana Das
- Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur, India
| | - Anthony J. Saviola
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Ashis K. Mukherjee
- Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur, India
- Institute of Advanced Study in Science and Technology, Guwahati, India
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Chung SH, Bigham M, Lappe RR, Chan B, Nagalakshmi U, Whitham SA, Dinesh‐Kumar SP, Jander G. A sugarcane mosaic virus vector for rapid in planta screening of proteins that inhibit the growth of insect herbivores. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:1713-1724. [PMID: 33763921 PMCID: PMC8428830 DOI: 10.1111/pbi.13585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/07/2021] [Accepted: 03/16/2021] [Indexed: 05/03/2023]
Abstract
Spodoptera frugiperda (fall armyworm) is a notorious pest that threatens maize production worldwide. Current control measures involve the use of chemical insecticides and transgenic maize expressing Bacillus thuringiensis (Bt) toxins. Although additional transgenes have confirmed insecticidal activity, limited research has been conducted in maize, at least partially due to the technical difficulty of maize transformation. Here, we describe implementation of a sugarcane mosaic virus (SCMV) vector for rapidly testing the efficacy of both endogenous maize genes and heterologous genes from other organisms for the control of S. frugiperda in maize. Four categories of proteins were tested using the SCMV vector: (i) maize defence signalling proteins: peptide elicitors (Pep1 and Pep3) and jasmonate acid conjugating enzymes (JAR1a and JAR1b); (ii) maize defensive proteins: the previously identified ribosome-inactivating protein (RIP2) and maize proteinase inhibitor (MPI), and two proteins with predicted but unconfirmed anti-insect activities, an antimicrobial peptide (AMP) and a lectin (JAC1); (iii) lectins from other plant species: Allium cepa agglutinin (ACA) and Galanthus nivalis agglutinin (GNA); and (iv) scorpion and spider toxins: peptides from Urodacus yaschenkoi (UyCT3 and UyCT5) and Hadronyche versuta (Hvt). In most cases, S. frugiperda larval growth was reduced by transient SCMV-mediated overexpression of genes encoding these proteins. Additionally, experiments with a subset of the SCMV-expressed genes showed effectiveness against two aphid species, Rhopalosiphum maidis (corn leaf aphid) and Myzus persicae (green peach aphid). Together, these results demonstrate that SCMV vectors are a rapid screening method for testing the efficacy and insecticidal activity of candidate genes in maize.
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Affiliation(s)
| | | | - Ryan R. Lappe
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIAUSA
| | - Barry Chan
- Department of Plant Biology and The Genome CenterCollege of Biological SciencesUniversity of CaliforniaDavisCAUSA
| | - Ugrappa Nagalakshmi
- Department of Plant Biology and The Genome CenterCollege of Biological SciencesUniversity of CaliforniaDavisCAUSA
| | - Steven A. Whitham
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIAUSA
| | - Savithramma P. Dinesh‐Kumar
- Department of Plant Biology and The Genome CenterCollege of Biological SciencesUniversity of CaliforniaDavisCAUSA
| | - Georg Jander
- Boyce Thompson Institute for Plant ResearchIthacaNYUSA
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Singh SK, Mandal MB, Ravindran R. Instillation of bradykinin into femoral artery elicits cardiorespiratory reflexes involving perivascular afferents in anesthetized rats. Physiol Int 2021; 107:40-54. [PMID: 32491287 DOI: 10.1556/2060.2020.00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 01/07/2020] [Indexed: 11/19/2022]
Abstract
The physiology of baroreceptors and chemoreceptors present in large blood vessels of the heart is well known in the regulation of cardiorespiratory functions. Since large blood vessels and peripheral blood vessels are of the same mesodermal origin, therefore, involvement of the latter in the regulation of cardiorespiratory system is expected. The role of perivascular nerves in mediating cardiorespiratory alterations produced after intra-arterial injection of a nociceptive agent (bradykinin) was examined in urethane-anesthetized male rats. Respiratory frequency, blood pressure, and heart rate were recorded for 30 min after the retrograde injection of bradykinin/saline into the femoral artery. In addition, paw edema was determined and water content was expressed as percentage of wet weight. Injection of bradykinin produced immediate tachypneic, hypotensive and bradycardiac responses of shorter latency (5-8 s) favoring the neural mechanisms involved in it. Injection of equi-volume of saline did not produce any responses and served as time-matched control. Paw edema was observed in the ipsilateral hind limb. Pretreatment with diclofenac sodium significantly attenuated the bradykinin-induced responses and also blocked the paw edema. Ipsilateral femoral and sciatic nerve sectioning attenuated bradykinin-induced responses significantly, indicating the origin of responses from the local vascular bed. Administration of bradykinin in the segment of an artery produced reflex cardiorespiratory changes by stimulating the perivascular nociceptors involving prostaglandins. This is a novel study exhibiting the role of peripheral blood vessels in the regulation of the cardiorespiratory system.
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Affiliation(s)
| | - M B Mandal
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, UP, India
| | - R Ravindran
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, UP, India
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Singh SK, Deshpande SB. B1-kinin receptors modulate Mesobuthus tamulus venom-induced vasosensory reflex responses in anesthetized rats. Indian J Pharmacol 2016; 48:388-393. [PMID: 27756949 PMCID: PMC4980926 DOI: 10.4103/0253-7613.186202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE Intra-arterial injection of Mesobuthus tamulus (BT) venom produces reflex vasosensory responses modulating cardiorespiratory parameters in albino rats. The present study was conducted to understand the role of kinin receptors in modulating vasosensory reflexes evoked by BT venom. MATERIALS AND METHODS In urethane-anesthetized rats, tracheostomy was performed to keep the airway patent. The femoral artery was cannulated proximally, as well as distally, to record the blood pressure (BP) and to inject the chemicals, respectively. Electrocardiographic and respiratory excursions were recorded to compute the heart rate (HR) and respiratory rate (RR). A group of animals was pretreated with saline/kinin receptor antagonists intra-arterially (B1/B2 receptor antagonists) before the injection of venom. RESULTS After intra-arterial injection of BT venom (1 mg/kg), there was an immediate increase in RR, which reached to 40% within 30 s, followed by a decrease of 40%. Further, there was sustained increase in RR (50%) up to 60 min. The BP started to increase at 40 s, peaking at 5 min (50%), and remained above the initial level up to 60 min. The bradycardiac response started after 5 min which peaked (50% of initial) at 25 min and remained at that level up to 60 min. In B1 receptor antagonist (des-Arg) pretreated animals, venom-induced cardiovascular responses were attenuated (by 20-25% in mean arterial pressure and HR) significantly but not in B2 receptor antagonist (Hoe-140) pretreated animals. Either of the antagonists failed to alter the RR responses. CONCLUSIONS BT venom-induced vasosensory reflex responses modulating cardiovascular parameters are mediated via B1-kinin receptors in anesthetized rats.
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Affiliation(s)
- Sanjeev K Singh
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Shripad B Deshpande
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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The unfulfilled promises of scorpion insectotoxins. J Venom Anim Toxins Incl Trop Dis 2015; 21:16. [PMID: 26085828 PMCID: PMC4470000 DOI: 10.1186/s40409-015-0019-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/18/2015] [Indexed: 01/09/2023] Open
Abstract
Since the description and biochemical characterization of the first insect-specific neurotoxins from scorpion venoms, almost all contributions have highlighted their potential application as leads for the development of potent bioinsecticides. Their practical use, however, has been hindered by different factors, some of which are intrinsically related to the toxins and other external determinants. Recent developments in the understanding of the action mechanisms of the scorpion insectotoxins and their bioactive surfaces, coupled with the exploration of novel bioinsecticide delivery systems have renewed the expectations that the scorpion insectotoxins could find their way into commercial applications in agriculture, as part of integrated pest control strategies. Herein, we review the current arsenal of available scorpion neurotoxins with a degree of specificity for insects, the progress made with alternative delivery methods, and the drawbacks that still preclude their practical use.
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Trancriptomic approach reveals the molecular diversity of Hottentotta conspersus (Buthidae) venom. Toxicon 2015; 99:73-9. [DOI: 10.1016/j.toxicon.2015.03.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/20/2015] [Accepted: 03/25/2015] [Indexed: 11/21/2022]
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Chlorotoxin: a helpful natural scorpion peptide to diagnose glioma and fight tumor invasion. Toxins (Basel) 2015; 7:1079-101. [PMID: 25826056 PMCID: PMC4417956 DOI: 10.3390/toxins7041079] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/22/2014] [Accepted: 02/20/2015] [Indexed: 11/17/2022] Open
Abstract
Chlorotoxin is a small 36 amino-acid peptide identified from the venom of the scorpion Leiurus quinquestriatus. Initially, chlorotoxin was used as a pharmacological tool to characterize chloride channels. While studying glioma-specific chloride currents, it was soon discovered that chlorotoxin possesses targeting properties towards cancer cells including glioma, melanoma, small cell lung carcinoma, neuroblastoma and medulloblastoma. The investigation of the mechanism of action of chlorotoxin has been challenging because its cell surface receptor target remains under questioning since two other receptors have been claimed besides chloride channels. Efforts on chlorotoxin-based applications focused on producing analogues helpful for glioma diagnosis, imaging and treatment. These efforts are welcome since gliomas are very aggressive brain cancers, close to impossible to cure with the current therapeutic arsenal. Among all the chlorotoxin-based strategies, the most promising one to enhance patient mean survival time appears to be the use of chlorotoxin as a targeting agent for the delivery of anti-tumor agents. Finally, the discovery of chlorotoxin has led to the screening of other scorpion venoms to identify chlorotoxin-like peptides. So far several new candidates have been identified. Only detailed research and clinical investigations will tell us if they share the same anti-tumor potential as chlorotoxin.
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Arzamasov AA, Vassilevski AA, Grishin EV. Chlorotoxin and related peptides: Short insect toxins from scorpion venom. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2014; 40:387-98. [DOI: 10.1134/s1068162014040013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Tianpei X, Zhu Y, Li S. Optimized scorpion polypeptide LMX: a pest control protein effective against rice leaf folder. PLoS One 2014; 9:e100232. [PMID: 24964088 PMCID: PMC4070919 DOI: 10.1371/journal.pone.0100232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 05/24/2014] [Indexed: 11/25/2022] Open
Abstract
Lepidopteran insect pests are the main class of pests causing significant damage to crop plant yields. Insecticidal scorpion peptides exhibit toxicity specific for insects. Here, we report that a peptide LMX, optimized from the insect-specific scorpion neurotoxin LqhIT2, showed high levels of activity against rice leaf folder in vitro and in planta. Oral ingestion of LMX protein led to a significant decrease in feeding on rice leaves, repression of larval growth and development, delay in molting, and increase in larval lethality. Compared with LqhIT2 protein, the stability and insecticidal efficacy of LMX was better. Meanwhile, biochemical analysis showed that LMX protein ingestion dramatically decreased ecdysone content in rice leaf folder larvae, and down-regulated enzymatic activities of the detoxification system (α-naphthyl acetate esterase and glutathione S-transferase), the digestive system (tryptase and chymotrypsin), and the antioxidant system (catalase). These changes were tightly correlated with the dosage of LMX protein. Transgene analysis showed that the rate of leaf damage, and the number of damaged tillers and leaves in the transgenic line were greatly reduced relative to wild type plants and empty vector plants. Based on these observations, we propose that the insect-specific scorpion neurotoxin peptide LMX is an attractive and effective alternative molecule for the protection of rice from rice leaf folder.
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Affiliation(s)
- Xiuzi Tianpei
- State Key Laboratory of Hybrid Rice; Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture; Engineering Research Center for Plant Biotechology and Germplasm Utilization of Ministry of Education; College of Life Sciences, Wuhan University, Wuhan, China
| | - Yingguo Zhu
- State Key Laboratory of Hybrid Rice; Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture; Engineering Research Center for Plant Biotechology and Germplasm Utilization of Ministry of Education; College of Life Sciences, Wuhan University, Wuhan, China
| | - Shaoqing Li
- State Key Laboratory of Hybrid Rice; Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture; Engineering Research Center for Plant Biotechology and Germplasm Utilization of Ministry of Education; College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail:
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Smith JJ, Herzig V, King GF, Alewood PF. The insecticidal potential of venom peptides. Cell Mol Life Sci 2013; 70:3665-93. [PMID: 23525661 PMCID: PMC11114029 DOI: 10.1007/s00018-013-1315-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/27/2013] [Accepted: 02/28/2013] [Indexed: 12/19/2022]
Abstract
Pest insect species are a burden to humans as they destroy crops and serve as vectors for a wide range of diseases including malaria and dengue. Chemical insecticides are currently the dominant approach for combating these pests. However, the de-registration of key classes of chemical insecticides due to their perceived ecological and human health risks in combination with the development of insecticide resistance in many pest insect populations has created an urgent need for improved methods of insect pest control. The venoms of arthropod predators such as spiders and scorpions are a promising source of novel insecticidal peptides that often have different modes of action to extant chemical insecticides. These peptides have been optimized via a prey-predator arms race spanning hundreds of millions of years to target specific types of insect ion channels and receptors. Here we review the current literature on insecticidal venom peptides, with a particular focus on their structural and pharmacological diversity, and discuss their potential for deployment as insecticides.
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Affiliation(s)
- Jennifer J. Smith
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Volker Herzig
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Paul F. Alewood
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
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Stroud MR, Hansen SJ, Olson JM. In vivo bio-imaging using chlorotoxin-based conjugates. Curr Pharm Des 2012; 17:4362-71. [PMID: 22204434 DOI: 10.2174/138161211798999375] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 11/02/2011] [Indexed: 01/10/2023]
Abstract
Surgical resection remains the primary component of cancer therapy. The precision required to successfully separate cancer tissue from normal tissue relies heavily on the surgeon's ability to delineate the tumor margins. Despite recent advances in surgical guidance and monitoring systems, intra-operative identification of these margins remains imprecise and directly influences patient prognosis. If the surgeon had improved tools to distinguish these margins, tumor progression and unacceptable morbidity could be avoided. In this article, we review the history of chlorotoxin and its tumor specificity and discuss the research currently being generated to target optical imaging agents to cancer tissue.
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Affiliation(s)
- Mark R Stroud
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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Mohammadpour Dounighi N, Eskandari R, Avadi MR, Zolfagharian H, Mir Mohammad Sadeghi A, Rezayat M. Preparation and in vitro characterization of chitosan nanoparticles containing Mesobuthus eupeus scorpion venom as an antigen delivery system. J Venom Anim Toxins Incl Trop Dis 2012. [DOI: 10.1590/s1678-91992012000100006] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Zootoxic effects of reduviid Rhynocoris marginatus (Fab.) (Hemiptera: Reduviidae) venomous saliva on Spodoptera litura (Fab.). Toxicon 2011; 58:415-25. [PMID: 21787800 DOI: 10.1016/j.toxicon.2011.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 06/03/2011] [Accepted: 06/06/2011] [Indexed: 11/24/2022]
Abstract
Rhynocoris marginatus is a predominant and potential reduviid predator of many economically important pests in India. The venomous saliva (VS) was collected by milking method and diluted with HPLC grade water to prepare different concentrations (200, 400, 600, 800 and 1000ppm). The VS from R. marginatus was found to be toxic and the LD(50) of the VS in Spodoptera litura third instar were 768 and 929ppm at 48 and 96h for microinjection and oral toxicity studies, respectively. Level of hydrolase and detoxification enzymes significantly decreased in a dose-dependent manner after treating the host with VS for 96h. A decrease in carbohydrate (21%) and lipid (46%) contents and an increase in the protein content (50%) were prominent in the experimental category. The VS reduced the relative growth rate, approximate digestibility, efficiency of conversion of ingested and digested food of S. litura in the oral toxicity study. Salivary venom inhibits the haemocytes from aggregation and affects spreading behavior of haemocytes separated from the fifth stadium larvae of S. litura. The result showed that VS toxins caused mortality, changed the nutritional indices, and altered the levels of macromolecule quantity and digestive enzymes of S. litura. We concluded that the VS of R. marginatus is venomous to a prey species, S. litura.
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Maurya AN, Deshpande SB. Involvement of NO-guanylyl cyclase pathway for the depression of spinal monosynaptic reflex by Mesobuthus tamulus venom in neonatal rat in vitro. Life Sci 2011; 88:886-91. [PMID: 21447347 DOI: 10.1016/j.lfs.2011.03.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2010] [Revised: 01/31/2011] [Accepted: 03/22/2011] [Indexed: 11/17/2022]
Abstract
AIMS The present study was undertaken to evaluate the role of nitric oxide (NO) in Mesobuthus tamulus (MBT) venom-induced depression of spinal reflexes. MAIN METHODS Experiments were performed on isolated hemisected spinal cords from 4 to 6day old rats. Stimulation of a dorsal root with supramaximal strength evoked monosynaptic (MSR) and polysynaptic reflex (PSR) potentials in the corresponding segmental ventral root. KEY FINDINGS Superfusion of MBT venom (0.3μg/ml) depressed the spinal reflexes in a time-dependent manner and the maximum depression was seen at 10min (MSR by 63%; PSR by 79%). The time to produce 50% depression (T-50) of MSR and PSR was 7.7±1.3 and 5.7±0.5min, respectively. Pretreatment with bicuculline (1μM; GABA(A) receptor antagonist) or strychnine (1μM; glycine(A) receptor antagonist) did not block the venom-induced depression of spinal reflexes. However, Nω-nitro-L-arginine methyl ester (L-NAME, 100 or 300μM; NO synthase inhibitor) or hemoglobin (Hb, 100μM; NO scavenger) antagonized the venom-induced depression of MSR. Further, soluble guanylyl cylase inhibitors (1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one, ODQ; 1μM or methylene blue, 100μM) also antagonized the venom-induced depression of MSR but not PSR. Nitrite concentration (indicator of NO activity) of the cords exposed to venom (0.3μg/ml) was not different from the control group. SIGNIFICANCE The results indicate that venom-induced depression of MSR is mediated via NO-guanylyl cyclase pathway without involving GABAergic or glycinergic system.
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Affiliation(s)
- Amar N Maurya
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, UP, India
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Rjeibi I, Mabrouk K, Mosrati H, Berenguer C, Mejdoub H, Villard C, Laffitte D, Bertin D, Ouafik L, Luis J, Elayeb M, Srairi-Abid N. Purification, synthesis and characterization of AaCtx, the first chlorotoxin-like peptide from Androctonus australis scorpion venom. Peptides 2011; 32:656-63. [PMID: 21262299 DOI: 10.1016/j.peptides.2011.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 01/11/2011] [Accepted: 01/11/2011] [Indexed: 01/18/2023]
Abstract
AaCtx is the first chlorotoxin-like peptide isolated from Androctonus australis scorpion venom. Its amino acid sequence shares 70% similarity with chlorotoxin from Leiurus quinquestriatus scorpion venom, from which it differs by twelve amino acids. Due to its very low concentration in venom (0.05%), AaCtx was chemically synthesized. Both native and synthetic AaCtx were active on invasion and migration of human glioma cells. However, their activity was found to be lower than that of chlorotoxin. The molecular model of AaCtx shows that most of amino acids differing between AaCtx and chlorotoxin are localized on the N-terminal loop and the α-helix. Based on known compounds that block chloride channels, we suggest that the absence of negative charged amino acids on AaCtx structure may be responsible for its weak activity on glioma cells migration and invasion. This finding serves as a starting point for structure-function relationship studies leading to design high specific anti-glioma drugs.
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Affiliation(s)
- Ilhem Rjeibi
- Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13, Place Pasteur, BP 74, 1002 Belvédère, Universités Tunis-El Manar, Tunisia
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Heinen TE, Gorini da Veiga AB. Arthropod venoms and cancer. Toxicon 2011; 57:497-511. [DOI: 10.1016/j.toxicon.2011.01.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 12/13/2010] [Accepted: 01/04/2011] [Indexed: 12/29/2022]
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Fitches EC, Bell HA, Powell ME, Back E, Sargiotti C, Weaver RJ, Gatehouse JA. Insecticidal activity of scorpion toxin (ButaIT) and snowdrop lectin (GNA) containing fusion proteins towards pest species of different orders. PEST MANAGEMENT SCIENCE 2010; 66:74-83. [PMID: 19728320 DOI: 10.1002/ps.1833] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
BACKGROUND The toxicity of a fusion protein, ButalT/GNA, comprising a venom toxin (ButaIT) derived from the red scorpion, Mesobuthus tamulus (F.), and Galanthus nivalis agglutinin (GNA), was evaluated under laboratory conditions against several pest insects. Insecticidal activity was compared with SFI1/GNA, a fusion comprising a venom toxin (SFI1) derived from the European spider Segestria florentina (Rossi) and GNA, which has been previously demonstrated to be effective against lepidopteran and hemipteran pests, and to GNA itself. RESULTS Injection assays demonstrated that both fusion proteins were toxic to lepidopteran larvae, dipteran adults, coleopteran adults and larvae and dictyopteran nymphs. ButalT/GNA was more toxic than SFI1/GNA in all cases. GNA itself made a minor contribution to toxicity. Oral toxicity of ButalT/GNA towards lepidopteran pests was confirmed against neonate Spodoptera littoralis (Boisd.), where incorporation at 2% dietary protein resulted in 50% mortality and > 85% reduction in growth compared with controls. ButaIT/GNA was orally toxic to Musca domestica L. adults, causing 75% mortality at 1 mg mL(-1) in aqueous diets and, at 2 mg g(-1) it was orally toxic to Tribolium castaneum (Herbst.), causing 60% mortality and a 90% reduction in growth. CONCLUSIONS Toxicity of the ButaIT/GNA recombinant fusion protein towards a range of insect pests from different orders was demonstrated by injection bioassays. Feeding bioassays demonstrated the potential use of the ButaIT/GNA fusion protein as an orally active insecticide against lepidopteran, dipteran and coleopteran pests. These experiments provide further evidence that the development of fusion protein technology for the generation of new, biorational, anti-insect molecules holds significant promise.
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Kanoo S, Mandal MB, Alex AB, Deshpande SB. Cardiac dysrhythmia produced by Mesobuthus tamulus venom involves NO-dependent G-Cyclase signaling pathway. Naunyn Schmiedebergs Arch Pharmacol 2008; 379:525-32. [PMID: 19037630 DOI: 10.1007/s00210-008-0375-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2008] [Accepted: 11/06/2008] [Indexed: 11/29/2022]
Abstract
Role of G-protein coupled pathways in modulating the cardiotoxic effects produced by Indian red scorpion (Mesobuthus tamulus) venom were examined. The isometric contractions of spontaneously beating or paced (3.5 Hz) rat right atrial preparations in vitro were recorded. The cumulative concentration (0.01-3.0 microg/ml)-response of venom on spontaneously beating atria exhibited a marked decrease in rate (by 55%) and an increase in force (by 92%) only at a higher concentration (3.0 microg/ml). The venom-induced decrease in rate and increase in force were sensitive to atropine, N-omega-nitro-L-arginine methylester (NO synthase inhibitor) and methylene blue (guanylyl cyclase inhibitor). Further, nifedipine, a Ca(2+) channel antagonist, blocked the force changes but not the rate changes induced by venom. In the paced atrium, on the other hand, a concentration-dependent decrease in force was observed, and at 3 microg/ml, the decrease was 50%. Pretreatment with nifedipine, but not with methylene blue, significantly attenuated the venom-induced force changes in paced atrium. The observations of this study demonstrate that the venom-induced atrial dysrhythmia is mediated through the muscarinic receptor-dependent NO-G-cyclase cell-signaling pathways.
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Affiliation(s)
- Sadhana Kanoo
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221 005, India
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21
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Fan X, Zheng B, Fu Y, Sun Y, Liang A. Baculovirus-mediated expression of a Chinese scorpion neurotoxin improves insecticidal efficacy. Sci Bull (Beijing) 2008. [DOI: 10.1007/s11434-008-0242-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Jeffers LA, Michael Roe R. The movement of proteins across the insect and tick digestive system. JOURNAL OF INSECT PHYSIOLOGY 2008; 54:319-332. [PMID: 18177888 DOI: 10.1016/j.jinsphys.2007.10.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 10/20/2007] [Accepted: 10/22/2007] [Indexed: 05/25/2023]
Abstract
The movement of intact proteins across the digestive system was shown in a number of different blood-feeding and non-blood-feeding insects in the orders Blattaria, Coleoptera, Diptera, Hemiptera, Lepidoptera, Orthoptera, Neuroptera and Siphonaptera, as well as in two tick families Ixodidae and Argasidae. Protein movement was observed for both normal dietary and xenobiotic proteins, which suggest that the mechanism for transfer is not substrate specific. The number of studies on the mechanism of movement is limited. The research so far suggests that movement can occur by either a transcellular or an intercellular pathway in the ventriculus with most of the research describing the former. Transfer is by continuous diffusion with no evidence of pinocytosis or vesicular transport common in mammalian systems. Proteins can move across the digestive system without modification of their primary or multimeric structure and with retention of their functional characteristics. Accumulation in the hemolymph is the result of the protein degradation rate in the gut and hemolymph and transfer rate across the digestive system and can be highly variable depending on species. Research on the development of delivery systems to enhance protein movement across the insect digestive system is in its infancy. The approaches so far considered with some success include the use of lipophilic-polyethylene glycol (PEG) polymers, the development of fusion proteins with lectins, reduced gut protease activity and the development of amphiphilic peptidic analogs. Additional research on understanding the basic mechanisms of protein delivery across the insect digestive system, the importance of structure activity in this transfer and the development of technology to improve movement across the gut could be highly significant to the future of protein and nucleic acid-based insecticide development as well as traditional chemical insecticidal technologies.
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Affiliation(s)
- Laura A Jeffers
- Department of Entomology, Dearstyne Entomology Building, North Carolina State University, Raleigh, NC 27695-7647, USA
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23
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Matsushita N, Miyashita M, Sakai A, Nakagawa Y, Miyagawa H. Purification and characterization of a novel short-chain insecticidal toxin with two disulfide bridges from the venom of the scorpion Liocheles australasiae. Toxicon 2007; 50:861-7. [PMID: 17681581 DOI: 10.1016/j.toxicon.2007.06.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 06/20/2007] [Accepted: 06/21/2007] [Indexed: 10/23/2022]
Abstract
Scorpion venoms contain a variety of peptides toxic to mammals, insects and crustaceans. Most of the scorpion toxins have been isolated from the venoms of scorpions in the family Buthidae, but little interest has been paid to non-Buthidae scorpions. In this study, we isolated a short-chain insecticidal toxin (LaIT1) from the venom of the scorpion Liocheles australasiae belonging to the Hemiscorpiidae family. This toxin showed insect toxicity against crickets at a dose of 1.0 microg/insect, but no toxicity was observed against mice even after injection of 1.0 microg of LaIT1 via the intracerebroventricular route, suggesting that the effect of the toxin is insect-selective. Edman sequencing and mass spectrometric analysis revealed that the toxin is composed of 36 amino acid residues and cross-linked by only two disulfide bridges. The pattern of the disulfide bridges was assigned by LC/MS analysis after enzymatic digestion. LaIT1 shows no sequence homology to any other known toxins, suggesting that this toxin represents a novel structural motif class.
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Affiliation(s)
- Nobuto Matsushita
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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Miyashita M, Otsuki J, Hanai Y, Nakagawa Y, Miyagawa H. Characterization of peptide components in the venom of the scorpion Liocheles australasiae (Hemiscorpiidae). Toxicon 2007; 50:428-37. [PMID: 17559900 DOI: 10.1016/j.toxicon.2007.04.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Revised: 04/09/2007] [Accepted: 04/10/2007] [Indexed: 11/25/2022]
Abstract
Scorpion venoms are composed of a number of neurotoxic peptides. A variety of toxins have been isolated from the venoms of scorpions of the family Buthidae, however, little interest has been paid to non-Buthidae scorpions. In this study, we examined the toxicity of the venom of Liocheles australasiae (Hemiscorpiidae) to mice and crickets, and characterized the peptide components by HPLC and mass spectrometry. Over 200 components were detected in the L. australasiae venom by LC/MS analysis, with components of molecular masses ranging from 500 to 5000 Da being particularly abundant. A number of peptides contained two to four disulfide bridges, which was estimated based on the mass difference after derivatization of Cys residues. A peptide having a monoisotopic molecular mass of 7781.6 Da and four disulfide bridges was isolated from the venom. The peptide has a primary structure similar in terms of the position of eight Cys residues to those observed in several peptides found from scorpions, ticks and insects, although biological roles of these peptides are unknown.
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Affiliation(s)
- Masahiro Miyashita
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
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25
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Abstract
Since the introduction of DDT in the 1940s, arthropod pest control has relied heavily upon chemical insecticides. However, the development of insect resistance, an increased awareness of the real and perceived environmental and health impacts of these chemicals, and the need for systems with a smaller environmental footprint has stimulated the search for new insecticidal compounds, novel molecular targets, and alternative control methods. In recent decades a variety of biocontrol methods employing peptidic or proteinaceous insect-specific toxins derived from microbes, plants and animals have been examined in the laboratory and field with varying results. Among the many interdependent factors involved with the production of a cost-effective pesticide--production expense, kill efficiency, environmental persistence, pest-specificity, pest resistance-development, public perception and ease of delivery--sprayable biopesticides have not yet found equal competitive footing with chemical counterparts. However, while protein/peptide-based biopesticides continue to have limitations, advances in the technology, particularly of genetically modified organisms as biopesticidal delivery systems, has continually progressed. This review highlights the varieties of delivery methods currently practiced, examining the strengths and weaknesses of each method.
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26
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Newton KA, Clench MR, Deshmukh R, Jeyaseelan K, Strong PN. Mass fingerprinting of toxic fractions from the venom of the Indian red scorpion, Mesobuthus tamulus: biotope-specific variation in the expression of venom peptides. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:3467-3476. [PMID: 17918210 DOI: 10.1002/rcm.3240] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The red scorpion, Mesobuthus tamulus, is found in two distinct biotopes within the Indian state of Maharastra-a tropical, sea-level biotope and a semi-arid biotope, up to 600 m. Scorpions from these two geographical areas show marked differences in toxicity. Using mass spectrometry, we have shown biotope-specific variation in the expression of peptides from scorpions collected from these two distinct areas. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) and reversed-phase liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI-MS) were assessed as techniques for obtaining mass fingerprint data. On line LC/ESI-MS was judged to be the method of choice and unique biotope-specific mass fingerprints, with key diagnostic markers, were obtained.
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Affiliation(s)
- Kirsti A Newton
- Biosciences Division, Sheffield Hallam University, Sheffield S1 1WB, UK.
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Trung NP, Fitches E, Gatehouse JA. A fusion protein containing a lepidopteran-specific toxin from the South Indian red scorpion (Mesobuthus tamulus) and snowdrop lectin shows oral toxicity to target insects. BMC Biotechnol 2006; 6:18. [PMID: 16542451 PMCID: PMC1459149 DOI: 10.1186/1472-6750-6-18] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Accepted: 03/16/2006] [Indexed: 05/07/2023] Open
Abstract
Background Despite evidence suggesting a role in plant defence, the use of plant lectins in crop protection has been hindered by their low and species-specific insecticidal activity. Snowdrop lectin (Galanthus nivalis agglutinin; GNA) is transported to the haemolymph of insects after oral ingestion, and can be used as a basis for novel insecticides. Recombinant proteins containing GNA expressed as a fusion with a peptide or protein, normally only toxic when injected into the insect haemolymph, have the potential to show oral toxicity as a result of GNA-mediated uptake. Results A gene encoding a toxin, ButaIT, from the red scorpion (Mesobuthus tamulus) was synthesised and assembled into expression constructs. One construct contained ButaIT alone, whereas the other contained ButaIT fused N-terminally to a GNA polypeptide (ButaIT/GNA). Both recombinant proteins were produced using the yeast Pichia pastoris as an expression host, and purified. Recombinant ButaIT and ButaIT/GNA were acutely toxic when injected into larvae of tomato moth (Lacanobia oleracea), causing slow paralysis, leading to mortality or decreased growth. ButaIT/GNA was chronically toxic when fed to L. oleracea larvae, causing decreased survival and weight gain under conditions where GNA alone was effectively non-toxic. Intact ButaIT/GNA was detected in larval haemolymph from insects fed the fusion protein orally, demonstrating transport of the linked polypeptide across the gut. Proteolysis of the fusion protein was also observed. ButaIT/GNA was significantly more toxic that GNA alone when fed to the homopteran Nilaparvata lugens (rice brown planthopper) in liquid artificial diet. Conclusion The ButaIT/GNA recombinant fusion protein is toxic to lepidopteran larvae both when injected and when fed orally, showing the utility of GNA as a carrier to transport potentially toxic peptides and proteins across the insect gut. Although ButaIT has been claimed to be lepidopteran-specific, the fusion protein has more wide-ranging insecticidal activity. Fusion proteins based on plant lectins have potential applications in crop protection, both as exogenously applied treatments and as endogenous products in transgenic plants.
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Affiliation(s)
- Nghia Pham Trung
- School of Biological and Biomedical Sciences, University of Durham, Science Laboratories, South Road, Durham DH1 3LE, UK
- Department of Biotechnology, Cuu Long Delta Rice Research Institute, O Mon, Can Tho, Viet Nam
| | - Elaine Fitches
- Central Science Laboratory, Department for Environment, Food and Rural Affairs, Sand Hutton, York YO41 1LZ, UK
| | - John A Gatehouse
- School of Biological and Biomedical Sciences, University of Durham, Science Laboratories, South Road, Durham DH1 3LE, UK
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Rajendra W, Hackett KJ, Buckley E, Hammock BD. Functional expression of lepidopteran-selective neurotoxin in baculovirus: potential for effective pest management. Biochim Biophys Acta Gen Subj 2005; 1760:158-63. [PMID: 16406338 DOI: 10.1016/j.bbagen.2005.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2005] [Revised: 10/23/2005] [Accepted: 11/16/2005] [Indexed: 11/23/2022]
Abstract
Recombinant baculovirus expressing insect-selective neurotoxins derived from venomous animals are considered as an attractive alternative to chemical insecticides for efficient insect control agents. Recently we identified and characterized a novel lepidopteran-selective toxin, Buthus tamulus insect-selective toxin (ButaIT), having 37 amino acids and eight half cysteine residues from the venom of the South Indian red scorpion, Mesobuthus tamulus. The synthetic toxin gene containing the ButaIT sequence in frame to the bombyxin signal sequence was engineered into a polyhedrin positive Autographa californica nuclear polyhedrosis virus (AcMNPV) genome under the control of the p10 promoter. Toxin expression in the haemolymph of infected larvae of Heliothis virescens and also in an insect cell culture system was confirmed by western blot analysis using antibody raised against the GST-ButaIT fusion protein. The recombinant NPV (ButaIT-NPV) showed enhanced insecticidal activity on the larvae of Heliothis virescens as evidenced by a significant reduction in median survival time (ST50) and also a greater reduction in feeding damage as compared to the wild-type AcMNPV.
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Affiliation(s)
- Wudayagiri Rajendra
- Division of Molecular Biology, Department of Zoology, Sri Venkateswara University, Tirupati-517 502, India.
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29
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Singh SK, Deshpande SB. Intra-arterial injection of Mesobuthus tamulus venom elicits cardiorespiratory reflexes involving perivascular afferents. Toxicon 2005; 46:820-6. [PMID: 16202438 DOI: 10.1016/j.toxicon.2005.08.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2005] [Revised: 08/22/2005] [Accepted: 08/24/2005] [Indexed: 11/17/2022]
Abstract
Role of perivascular afferents for the cardiorespiratory alterations produced by Mesobuthus tamulus (BT) envenomation was examined in urethane-anaesthetized male rats. Blood pressure (BP), respiratory rate (RR) and heart rate (HR) were recorded after injecting BT venom/saline in the distal end of femoral artery for 60 min. In addition, paw oedema was also determined. Injection of venom produced an immediate (within 2 s) increase in RR followed by a decrease and finally a sustained increase up to 60 min. BP was increased (within 10 s) by 30-50%, which gradually declined but remained above the initial level up to 60 min. The bradycardiac response was late to occur (after 50 s) and the peak response was seen between 10 and 50 min, which remained at that level. There was oedema in the ipsilateral hind paw (venom injected side) as compared to contralateral side and saline control group. The oedema and cardiorespiratory changes were maximal at 1.0 mg/kg of venom. Pretreatment with indomethacin significantly attenuated the venom-induced responses and also blocked the paw oedema. Present experiments reveal that BT venom in a segment of an artery produces oedema by involving prostaglandins to sensitize the nociceptors present in perivascular tissues to evoke the cardiorespiratory reflexes.
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Affiliation(s)
- Sanjeev K Singh
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
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Deshpande SB, Alex AB, Jagannadham MV, Rao GRK, Tiwari AK. Identification of a novel pulmonary oedema producing toxin from Indian red scorpion (Mesobuthus tamulus) venom. Toxicon 2005; 45:735-43. [PMID: 15804522 DOI: 10.1016/j.toxicon.2005.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Revised: 09/28/2004] [Accepted: 01/13/2005] [Indexed: 10/25/2022]
Abstract
The experiments were conducted to identify the toxin that produces pulmonary oedema in Mesobuthus tamulus (BT) envenomed animals. Crude BT venom was subjected to Sephadex gel filtration (G-75) and the fractions were screened for optical density (OD), neurotoxicity (prolongation of compound action potential in frog sciatic nerve) and lethality. All these parameters exhibited a peak between 54-94 ml eluates. Fractions of this peak were pooled (SP) and loaded on to carboxymethyl cellulose column. The column was then eluted with increasing buffer concentrations at constant pH and temperature. Eluates were screened for neurotoxicity and OD. Four peaks of neurotoxic activity (T1-T4) were detected. T2 and T3 were lethal whereas T1 and T4 were non-lethal. T2 exhibited mainly neurotoxicity and failed to augment phenyldiguanide (PDG)-induced reflex response or to produce pulmonary oedema. T3 was having minimal neurotoxic actions but augmented PDG-reflex and produced pulmonary oedema. The effects of T3 persisted even after dialysis with 8 kDa cut-off filter but not those of T2. The T3 effects resembled toxic manifestations of BT venom and were blocked by aprotinin pre-treatment. T3 demonstrated a band at approximately 100 kDa in SDS-PAGE. The results demonstrate the presence of a lethal, high molecular weight, pulmonary oedema producing toxin in BT venom.
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Affiliation(s)
- S B Deshpande
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India.
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Pandey R, Deshpande SB. Protective effects of aprotinin on respiratory and cardiac abnormalities induced by Mesobuthus tamulus venom in adult rats. Toxicon 2004; 44:201-5. [PMID: 15246770 DOI: 10.1016/j.toxicon.2004.05.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2004] [Revised: 05/23/2004] [Accepted: 05/25/2004] [Indexed: 10/26/2022]
Abstract
Role of aprotinin (kallikrein-kinin synthesis inhibitor) in preventing the cardio-respiratory toxicity induced by Mesobuthus tamulus (BT) venom was evaluated. The effects of BT venom (5 mg/kg) on mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR), lung compliance and pulmonary water content were examined. BT venom produced alterations in MAP, HR and RR. The MAP changes were seen as an immediate fall (within 2 s) followed by a rise and subsequent progressive fall. The HR was decreased drastically after venom and never returned to initial value. The respiratory changes were manifested as prolonged apnea with intermittent shallow breathing. The animals died within 30-60 min. In these animals, the lung compliance was decreased as compared to saline treated controls and there was significant increase in pulmonary water content. In aprotinin pre-treated group, there was decrease in MAP, HR and RR within 2 s which returned to pre-venom level within 15 min and remained at that level thereafter. The animals survived for the period of observation (i.e. up to 120 min). The compliance and pulmonary water content in these animals were similar to control animals. The results indicate that aprotinin protects against the BT venom-induced cardio-pulmonary toxicity.
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Affiliation(s)
- Ratna Pandey
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
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Dhawan RD, Joseph S, Sethi A, Lala AK. Purification and characterization of a short insect toxin from the venom of the scorpion Buthus tamulus. FEBS Lett 2002; 528:261-6. [PMID: 12297317 DOI: 10.1016/s0014-5793(02)03326-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A short chain peptide has been isolated from the venom of a red scorpion of Indian origin, Buthus tamulus. This peptide was purified using ion exchange and reverse phase chromatography and was characterized by molecular weight determination and amino acid sequence. The primary structure analysis shows that BtITx3 is a short peptide of 35 amino acid residues having a molecular weight of 3796 Da. The toxin shows toxicity towards the Lepidopteran species of insect Helicoverpa armigera causing flaccid paralysis and even death within 24 h. It shows more than 50% homology with the short insectotoxins having four disulfide bridges, which suggests that the toxin belongs to the class of short chain toxins blocking the chloride ion channels. This sequence homology study has also helped to bring out the structure-function relationship between the various short toxins. Homology modeling done by using template structure of a known toxin indicated that this toxin consists of a similar alpha/beta scaffold, as present in other scorpion toxins.
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Affiliation(s)
- Ritu Dhawan Dhawan
- Biomembrane Lab, Department of Chemistry and School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
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