Some studies on the salivary anticoagulant components of the black fly Simulium vittatum (Diptera: Simuliidae).

Persistent Link:
http://hdl.handle.net/10150/186849
Title:
Some studies on the salivary anticoagulant components of the black fly Simulium vittatum (Diptera: Simuliidae).
Author:
Abebe, Makonnen.
Issue Date:
1994
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Three major experiments on the anticoagulant components of the saliva of some black fly species were conducted. These included investigations on anticoagulant activities against factor Xa and thrombin in the salivary gland extracts (SGE) of Simulium argus Williston, S. vittatum Zettersted, S. metallicum Bellardi, and S. ochraceum Walker using in vitro, chromogenic substrate assays, biochemical and molecular characterization of the anti-thrombin from the saliva of S. vittatum and determination of the target enzyme in the vertebrate coagulation cascade of a novel anticoagulant from the saliva of S. vittatum. The study on anticoagulant activities in the four simuliid species revealed factor Xa inhibition to be common in all four species while thrombin inhibition was detected only in S. argus and S. vittatum. Both bovine and human α-thrombins were inhibited with the highest activity occurring with S. argus SGE. Factor Xa inhibition was highest in S. ochraceum which is an anthropophilic species and vector of Onchocerca volvulus, and lowest in S. vittatum, a primiparous autogenous species that is also zoophilic. Total soluble SGE protein also varied among the four species with the highest concentration measured in S. ochraceum and the lowest in S. vittatum. In the second experiment, the anti-thrombin component of the saliva of S. vittatum was purified using a two-step reverse phase (RP) high performance liquid chromatography (HPLC) involving a C-8 macrosphere column. The molecular weight of the HPLC purified inhibitor was determined by laser desorption ionization mass spectrometry (LDI-MS) and was found to be 11,333 daltons. Studies on the effect of the molecule on other serine proteinases such as α-chymotrypsin, human neutrophil elastase, and human neutrophil cathepsin G showed that they are inhibited by the salivary anticoagulant. The N-terminal sequence for the first 35 amino acids was determined. The molecule has been named Simulidin. In the third experiment, a novel anticoagulant from the saliva of S. vittatum, with activities on factor V, was demonstrated using the activated partial thromboplastin time (APTT) in HPLC partially purified salivary lysate. Factor Xa and thrombin were unaffected by the inhibitor.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Entomology; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Cupp, Eddie W.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleSome studies on the salivary anticoagulant components of the black fly Simulium vittatum (Diptera: Simuliidae).en_US
dc.creatorAbebe, Makonnen.en_US
dc.contributor.authorAbebe, Makonnen.en_US
dc.date.issued1994en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThree major experiments on the anticoagulant components of the saliva of some black fly species were conducted. These included investigations on anticoagulant activities against factor Xa and thrombin in the salivary gland extracts (SGE) of Simulium argus Williston, S. vittatum Zettersted, S. metallicum Bellardi, and S. ochraceum Walker using in vitro, chromogenic substrate assays, biochemical and molecular characterization of the anti-thrombin from the saliva of S. vittatum and determination of the target enzyme in the vertebrate coagulation cascade of a novel anticoagulant from the saliva of S. vittatum. The study on anticoagulant activities in the four simuliid species revealed factor Xa inhibition to be common in all four species while thrombin inhibition was detected only in S. argus and S. vittatum. Both bovine and human α-thrombins were inhibited with the highest activity occurring with S. argus SGE. Factor Xa inhibition was highest in S. ochraceum which is an anthropophilic species and vector of Onchocerca volvulus, and lowest in S. vittatum, a primiparous autogenous species that is also zoophilic. Total soluble SGE protein also varied among the four species with the highest concentration measured in S. ochraceum and the lowest in S. vittatum. In the second experiment, the anti-thrombin component of the saliva of S. vittatum was purified using a two-step reverse phase (RP) high performance liquid chromatography (HPLC) involving a C-8 macrosphere column. The molecular weight of the HPLC purified inhibitor was determined by laser desorption ionization mass spectrometry (LDI-MS) and was found to be 11,333 daltons. Studies on the effect of the molecule on other serine proteinases such as α-chymotrypsin, human neutrophil elastase, and human neutrophil cathepsin G showed that they are inhibited by the salivary anticoagulant. The N-terminal sequence for the first 35 amino acids was determined. The molecule has been named Simulidin. In the third experiment, a novel anticoagulant from the saliva of S. vittatum, with activities on factor V, was demonstrated using the activated partial thromboplastin time (APTT) in HPLC partially purified salivary lysate. Factor Xa and thrombin were unaffected by the inhibitor.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEntomologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairCupp, Eddie W.en_US
dc.contributor.committeememberRibeiro, Jose M. C.en_US
dc.contributor.committeememberCollins, Richard C.en_US
dc.contributor.committeememberMare, C. Johnen_US
dc.identifier.proquest9506981en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.