Publication Date

1990

Document Type

Dissertation/Thesis

First Advisor

Hahin, Richard

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

LCSH

Leiurus Quinquestriatus Hebraeus; Toxins--Purification; Scorpions--Middle East--Venom

Abstract

Toxins were purified from crude venom obtained from Middle Eastern scorpions, Leiurus cruinouestriatus hebraeus (Lqh). Active fractions were purified using cationic exchange chromatography, and tested for their ability to lengthen and attenuate propagated compound action potentials (C.A.P.) recorded from frog sciatic nerves using the sucrose-gap technique. The most active purified toxin was tested for its ability to modify Na channels using the frog skeletal muscle vaseline-gap voltage-clamp. Using a two-step purification scheme, two fractions, from Leiurus quinauestriatus hebraeus containing toxins (Lqhl and Lqh2), absorbing at 280 nM, were found to be active in prolonging and attenuating the C.A.P. The two fractions were tested and compared to toxin V (Lqq5) from Leiurus quinauestriatus quinauestriatus (Lqq) obtained from North African scorpions. Lqhl and Lqh2 were purified to homogeniety and possessed molecular weights of 6390 and 5870 Daltons respectively; thus both toxins differ in size from Lqq5 (7462). Electrophysiological experiments suggested that three toxins are different. Both toxins, Lqhl and Lqh2, exhibited greater potency than Lqq5. Evidence from sucrose-gap and voltage-clamp experiments suggests that all three toxins act in a voltage-dependent fashion to bind to Na channels and block them, besides their well known ability to modify inactivation kinetics.

Comments

Includes bibliographical references (pages 53-55)

Extent

vii, 55 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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