Characterization of Some Novel Antimicrobial Peptides from African Common Toad, Sclerophrys regularis
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal Online
Abstract
The growing number of antimicrobial resistant bacteria have necessitated urgent need for
newer and effective antimicrobials. Antimicrobial peptides (AMPs) which are also called
host defense peptides are promising class of bioactives found in all living thing especially
amphibians. A total of 355 Sclerophrys regularis were collected and each toad was weighed
and 0.02mL/g of epinephrine (1mg/mL) was administered via the dorsal lymph sac of the
toad. The skin secretions were washed, lyophilized and stored at -20°C. The secretion was
purified using Sephadex G-50 gel purification column. The fractions showing antimicrobial
activities against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922,
Salmonella typhii ATCC 14028, Citrobacter freundii ATCC 8090, Staphylococcus aureus
ATCC 25913 and Candida albicans ATCC 3147 were further purified by RP- HPFC. The
purified fractions were lyophilized and m/z ratio peaks were determined using MALDI
TOF/TOF MS. The sequences corresponding to the peaks were determined using Mascot
Peptide Mass Fingerprint which revealed novel AMP sequences: IHAGKTVPIVK, MHLLWR
and LTGQIKNGLSGR which were named Regularin-2, Regularin-3 and Regularin-4
respectively. The MICs of purified fractions were between 50 – 200 µg/mL and the
antimicrobial activities were maintained when stored at -20 °C for 180 days and was
significant at p < 0.05. Bioprospecting of Nigerian toad specie (S. regularis) could yield
potential therapeutic AMP agents.
Description
Keywords
African common toad, Antimicrobial Peptides, AMPs, Sclerophrys regularis, Toad skin Secretion