Antibacterial and hemolytic activity of the skin of the terrestrial salamander, Plethodon cinereus (original) (raw)
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Antimicrobial peptide defenses in amphibian skin
2005
SYNOPSIS. One of the most urgent problems in conservation biology today is the continuing loss of amphibian populations on a global scale. Recent amphibian population declines in Australia, Central America, the western United States, Europe, and Africa have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis, which infects the skin. The skin of amphibians is critical for fluid balance, respiration, and transport of essential ions; and the immune defense of the skin must be integrated with these physiological responses. One of the natural defenses of the skin is production of antimicrobial peptides in granular glands. Discharge of the granular glands is initiated by stimulation of sympathetic nerves. To determine whether antimicrobial skin peptides play a role in protection from invasive pathogens, purified antimicrobial peptides and natural peptide mixtures recovered from the skin secretions of a number of species have been assayed for growth inhibition of the chytrid fungus. The general findings are that most species tested have one or more antimicrobial peptides with potent activity against the chytrid fungus, and natural mixtures of peptides are also effective inhibitors of chytrid growth. This supports the hypothesis that antimicrobial peptides produced in the skin are an important defense against skin pathogens and may affect survival of populations. We also report on initial studies of peptide depletion using norepinephrine and the kinetics of peptide recovery following induction. Approximately 80 nmoles/g of norepinephrine is required to deplete peptides, and peptide stores are not fully recovered at three weeks following this treatment. Because many species have defensive peptides and yet suffer chytrid-associated population declines, it is likely that other factors (temperature, conditions of hydration, ''stress,'' or pesticides) may alter normal defenses and allow for uncontrolled infection.
2011
In frogs, part of the important immune defence system of their skin is the secretion of antimicrobial peptides from granular glands. This study investigated the immune function of skin peptides in protection against bacterial pathogens associated with infectious bacterial dermatosepticemia under a number of environmental conditions and at certain stages of the life cycle of frogs. The natural peptide mixture of skin peptides was collected from skin secretions of three semi-aquatic Litoria frog species L. aurea, L. raniformis and L. ewingii and aquatic Xenopus laevis and assayed for activity against the bacterial pathogens: Aeromonas hydrophila, Chryseobacterium meningosepticum, Citrobacter freundii, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Serratia liquefaciens. The peptide mixtures of three frog species Xenopus laevis, Litoria aurea and Litoria raniformis showed activity against C. freundii, C. meningosepticum, K. pneumoniae and P. aeruginosa in vitro in...
Toxicon : official journal of the International Society on Toxinology, 2008
Peptidomic analysis of norepinephrine-stimulated skin secretions from Hose's rock frog Odorrana hosii (Boulenger, 1891) led to the isolation of 8 peptides with differential antibacterial activities. Structural characterization demonstrated that the peptides belonged to the esculentin-1 (1 peptide), esculentin-2 (1 peptide), brevinin-1 (2 peptides), brevinin-2 (2 peptides), and nigrocin-2 (2 peptides) families of antimicrobial peptides. Similar analysis of skin secretions from the Malaysian fire frog Hylarana picturata (Boulenger, 1920) led to the isolation and characterization of peptides belonging to the brevinin-1 (2 peptides), brevinin-2 (5 peptides), and temporin (1 peptide) families. The differences in antimicrobial activities of paralogous peptides provide insight into structure-activity relationships, emphasizing the importance of cationicity in determining potency. The substitution Lys11-->Gln in brevinin-1HSa (FLPAVLRVAAKIVPTVFCAISKKC) from O. hosii abolishes growth...
Antimicrobial properties of the skin secretions of frogs
South African Journal of Science, 2012
Antimicrobial resistance results in increased morbidity and mortality, and increased health-care costs. Therefore the need to develop new classes of antibiotics is indispensable. Antimicrobial peptides are a relatively new class of potential antibiotics which are fast acting, possess broad-spectrum activity and are able to escape many of the currently known mechanisms of drug resistance. They have been shown to be active against Gram-negative and Gram-positive bacteria, fungi, enveloped viruses and even cancer cells. However, toxicity to healthy host cells remains a concern and has affected the clinical development of therapeutics based on antimicrobial peptides. The purpose of this review is to discuss recent advances in research focused on antimicrobial peptides from frogs and the challenges in conducting research in this area in southern Africa. An extensive literature review of relevant articles published between 1980 and the present was conducted using PubMed, ScienceDirect, Sabinet, Elsevier and GoogleScholar. There has been little research done on anurans from southern Africa which are endemic to the region, and there is therefore a need to focus on this group for the purposes of bioprospecting for potentially new antimicrobial peptide compounds.
Preliminary Study of Antimicrobial Activity of the Skin Secretions of Malaysian Frogs
Jurnal teknologi, 2016
Bioactive compounds that exhibit antimicrobial properties in frogs are parts of the animal defense against microbial infections. The lyophilized frog's skin secretions containing varies bioactive compounds were subjected to screen for their antimicrobial activity. This study was conducted as part of an effort on the search of antimicrobial peptides (AMPs) profiles of Malaysian frogs. The results indicate the collected frog skin secretion has antimicrobial effect against Gram-negative and Gram-positive bacteria. BLAST and standard phylogenetics were used to establish a preliminary identity of the frog samples.
The Journal of experimental biology, 2018
Amphibian skin is unique among vertebrate classes, containing a large number of multicellular exocrine glands that vary among species and have diverse functions. The secretions of skin glands contain a rich array of bioactive compounds including antimicrobial peptides (AMPs). Such compounds are important for amphibian innate immune responses and may protect some species from chytridiomycosis, a lethal skin disease caused by the fungal pathogens, (Bd) and (Bsal). While the bioactivity of skin secretions against Bd has been assessed for many amphibian taxa, similar studies are lacking for Bsal, a chytrid fungus that is especially pathogenic for salamanders. We studied the skin glands and their potential functions in the aquatic salamander, Three-toed Amphiuma (). Skin secretions of captive adult salamanders were analyzed by RP-HPLC and tested against the growth of Bd and Bsal using assays. We found that compounds within collected skin secretions were similar between male and female sa...
Peptides, 2010
Peptidomic analysis of norepinephrine-stimulated skin secretions of the South-East Asian frog Hylarana erythraea (formerly Rana erythraea partim) has led to the identification of multiple peptides with antimicrobial activity. Structural characterization of the peptides demonstrated that they belong to the brevinin-1 (3), brevinin-2 (2), esculentin-2 (4), and temporin (1) families. The values in parentheses indicate the number of paralogs. In addition, a peptide (GVIKSVLKGVAKTVALG ML.NH(2)) was isolated that shows some structural similarity to the brevinin-2-related peptides (B2RP) previously isolated from North American frogs of the genus Lithobates. A synthetic replicate of the species B2RP showed broad-spectrum growth inhibitory activity against reference strains of Escherichia coli (MIC=12.5 microM), Staphylococcus aureus (MIC=12.5 microM) and Candida albicans (MIC=50 microM) and was active against multidrug-resistant clinical isolates of Acetinobacter baumannii (MIC in the range...
Amphibian skin secretion is considered as a rich source of bioactive peptides. The present work describes the successful identification of three novel peptides named brevinin-1TEa, brevinin-2TEa and brevinin-2TEb present in the skin secretion of Indian bronzed frog Hylarana temporalis. The deduced open reading frame encoding the biosynthetic precursor of brevinin-1TEa consisted of 70 amino acid residues and brevinin-2TEa and brevinin-2TEb consisted of 71 and 72 amino acids, respectively. All the three peptides showed higher antimicrobial activity against Gram-negative than against Gram-positive bacteria. On the basis of the antibacterial and haemolytic activity, brevinin-2TEb is the most potent peptide reported in the present study. Further research on these peptides may provide potential clue towards newer drug development to combat various microbial diseases.