Abstract:The venom of animals, including snakes, scorpions and spiders is a complex combination of proteins, peptides, and other biomolecules as well as some minerals. Among the biomolecules, some peptides prevent converting of angiotensin 1 to angiotensin 2 by inhibiting of the Angiotensin Converting Enzyme (ACE) and finally reducing the blood pressure in the victims. The aim of the present study was to isolate venom components of the three species of Iranian medically important scorpions and to study the bradykinin potentiating effect of them. Separation of the venom components for each scorpion was carried out using high performance liquid chromatography (HPLC). The range of fractions (zones) obtained in several replicates on Guinea pig ileum and rat uterus tissues were performed using organ bath instrument. The bioassays were resulted in the peptides including Z 1 and Z 2 regions of venom chromatogram of the Hottentotta sulcyi, Z 2 for Odontobutus doriea and Z 2 and Z 3 in Mesobutus eupeus venom demonstrated bradykinin potentiating effect.

Clostridium difficile has emerged as an increasingly important nosocomial pathogen and the prime causative agent of antibiotic-associated diarrhoea and pseudomembranous colitis in humans. In addition to toxins A and B, immunological studies using antisera from patients infected with C. difficile have shown that a number of other bacterial factors contribute to the pathogenesis, including surface proteins, which are responsible for adhesion, motility and other interactions with the human host. In this study, various clostridial targets, including FliC, FliD and cell wall protein 66, were expressed and purified. Phage antibody display yielded a large panel of specific recombinant antibodies, which were expressed, purified and characterised. Reactions of the recombinant antibodies with their targets were detected by enzyme-linked immunosorbent assay; and Western blotting suggested that linear rather than conformational epitopes were recognised. Binding of the recombinant antibodies to surface-layer proteins and their components showed strain specificity, with good recognition of proteins from C. difficile 630. However, no reaction was observed for strain R20291—a representative of the 027 ribotype. Binding of the recombinant antibodies to C. difficile M120 extracts indicated that a component of a surface-layer protein of this strain might possess immunoglobulin-binding activities. The recombinant antibodies against FliC and FliD proteins were able to inhibit bacterial motility.

Background: The production of antivenom from immunized animals is an established treatment for snakebites; however, antibody phage display technology may have the capacity to delivery results more quickly and with a better match to local need. Naja oxiana , the Iranian cobra, is a medically important species, responsible for a significant number of deaths annually. This study was designed as proof of principle to determine whether recombinant antibodies with the capacity to neutralize cobra venom could be isolated by phage display. Methods: Toxic fractions from cobra venom were prepared by chromatography and used as targets in phage display to isolate recombinant antibodies from a human scFv library. Candidate antibodies were expressed in E. coli HB2151 and purified by IMAC chromatography. The selected clones were analyzed in in vivo and in vitro experiments. Results: Venom toxicity was contained in two fractions. Around a hundred phage clones were isolated against each fraction, those showing the best promise were G12F3 and G1F4. While all chosen clones showed low but detectable neutralizing effect against Naja oxiana venom, clone G12F3 could inhibit PLA 2 activity. Conclusion: Therefore, phage display is believed to have a good potential as an approach to the development of snake antivenom.