Definition Antimicrobial Peptides - Assignment Example

4. Discussion This experiment has illustrated that antimicrobial peptides that are found in norepinephrine stimulated H. erythrae skin discharge belong to the well-elaborated families of brevinin-1, brevinin-2, temporin and esculentin-2, as illustrated in figure 3. According to Morikawa et al.1, both Brevinin-1 and Brevinin-2 peptides were initially recognized in R. brevipoda porsa’s skin, which was then re-categorized as pelophylax porous. However, the following studies have revealed that components of brevinin-1 families are largely distributed in both North American and Eurasian species, while brevinin-2 peptides, up to date, can only be found in the Eurasian ranids2 ,3. In the same way, members of the esculentin-2 peptide family were initially discovered among the Eurasian frog R. esculenta, which has now been renamed as a hybrid between P. ridibundus and P. lessonae4, but has also been identified in the skins of a few species belonging to the genera Rana, Lithobates, Pelophylax and Odorrana5. The MIC values in the H. erythrae could not be separately determined due to insufficient pure material, even though, the study revealed that peptides of esculenntin-2, brevinin-1 and brevinin-2 are active against both Gram-negative and Gram-positive bacteria, despite the fact that their therapeutic potential is usually restricted by high hemolytic activity against the human being erythrocytes6. The study also designated the 17 amino-acid residue, which is a very hydrophobic peptide FLPLIIGALSSLLPKI F.NH2 as a component of the temporin family and reclassified as temporin-Era. Components of the temporin family are largely distributed in the Eurasian and New World species as components of the Ranidae family7,8 and though distinguished by great amino acid sequence variability containing 13 amino acid residues. Figure 4 shows that temporin peptides containing 13 amino acid residues were recognized in the skins of H. latouchii9 R. sakuraii10 and H. guntheri11,12, and the intestine of R. tagoi13. In this study, pure material was also insufficient and therefore it was difficult to determine the MIC, temporin-Era related to most members of the family containing a single basic residue14, illustrated greater growth inhibitory activity against the Gram-positive bacteria S. aureus than against the Gram-negative bacteria E. coli. The classification of frogs found in the extensive Ranidae family has undergone through a significant revisions lately though many issues still need to be decided on. Studies based on morphological and molecular criteria depict that the previous Rana genus, consisting of more than 250 species, did not represent a monophyletic group15 with the outcome that numerous famous species have been re-categorized. The contemporary Frost16 recommendations partition the 338 species in the Ranidae species into 16 genera, retaining the genus Rana for a more controlled cluster of 48 species from North America and Eurasia. It should be noted that other well-known taxonomists have asserted that most species reclassifications are both premature and arbitrary, and it has been proposed that the Rana genus has to be preserved for all members of the North American family.17 Although the Japanese phylogeny18,19 and Chinese phylogeny20 of the brown frogs has been comprehensively studied, evolutionary interactions among different populations of the other frogs in India, Southeast Asia and India are incompletely understood. The earlier Rana erythraea has currently been reclassified alongside other 85 species from the African Savannas and tropical Asia in the widespread genus Hylarana.21 As revealed in figure six, cladistic study based on the amino acid series of 47 brevinin -2 peptides on 17 species from Asia has offered support for this analysis. Erythraea is the sister group to a well distinct clade in the phylogenetic tree that is generated by the neighbor –joining method, H as shown by the bar in figure six, consisting of the Chinese frog H. guntheri22 and the Malaysian frog H. picturata.23 Similar with the phylogenetic study that is based on the nucleotide series of mitochondrial genes, the Japanese brown frogs R. tsushimensis, R. pirica, R. sakuraii and R. ornativentris make up a well distinct separate clade24, and also the Chinese brown frog R. chensinensis is a sister-group to R. dybowskii.25 Evolutionary correlations between species belonging to the genera Odorrana, pelophylax and Glandirana are not thoroughly defined in this cladogram , thus it is evidently important to acquire brevinin-2 peptides structural data form other species. The assignment of a recently discovered antimicrobial peptide to a certain prior illustrated family is an arbitrary procedure and the evolution linkages of the peptide GVIKSVLKGVAKTVALGML.NH2 to more frog skin peptides is not fully clear. Until now, brevinin-2 peptides haven’t been discovered in any of the North American ranid species26 although C-terminally - amidated peptides having some structural resemblance to brevinin-2, though deficient of the C terminal cyclic heptapeptide domain (Cys-Lys-Xaa4-Cys) were secluded from the secretions of the skin from the current globe species, the mink frog Rana septentrionalis (reclassified as lithobates septentrionalis27 and the carpenter frog Rana Virgatipes reclassified as lithobates virgatipes.28 As revealed in figure four, the peptide from H. erythraea indicates limited structural remembrance to these peptides and thus has selected a brevinin- linked peptide (B2RP). Up to now, most of the frog skin antimicrobial peptides that have been investigated take on an amphipathic -helical conformation in a membrane-mimetic solvent for instance 50 percent trifluoroethanol-water.29 Rost et al30 predicts a secondary structure that shows that, B2RP has a higher likelihood of forming a firm -helical conformation involving residues (2-16) and a Schiffer-Edmunson wheel demonstration of the molecule31 reveals the amphipathic character of the helix as shown in figure seven. The helix in B2RP hydrophilic face is linked with a net charge of +4 (Lys4, Lys8, and Lys12 and -amino group of Gly1). The putative ortholog from L. septentrionalis together with H. erythraea B2RP indicated a higher growth inhibitory capability against the opportunistic yeast pathogen Candida albicans and also against the Gram-negative and Gram –positive bacteria. Almost every part of the globe has experienced the multidrug-resistant strains of Acinetobacter baumanni and this is seen as a key threat to the health of the public32,33. The Gram –negative opportunistic pathogen is liable to most infections such as bacteremia, pneumonia, peritonitis, meningitis. Additionally, this pathogen is also responsible for skin and urinary tract infections most of which are encountered in seriously ill patients and immunocompromised in intensive care units.34 The bacterium is known for its capacity to obtain new resistance determinants thus reducing treatment options35,36. As a result, there is a need for newer types of antimicrobial agent which the bacterium has not been exposed for the management of multi-drug resistant A. baumannii infections. An earlier investigation37 showed that B2RP from L. septentrionalis potently (MIC=3-6 μM) slowed down the growth of nosocomial isolates of multidrug-resistant A. baumannii though its rapeutic capacity was narrowed by fairly higher hemolytic action against human erythrocytes (LC50 = 90 μM). As revealed in Table 1, B2-RP from H. erythraea demonstrated a 2-fold lower effectiveness against the same clinical isolates although this shortcoming was counteracted by considerably lesser hemolytic activity (LC50 = 280 μM). Therefore, this peptide indicates capacity for growth in a therapeutically helpful agent for the general management of A. baumannii infections. References Bevier CR, Sonnevend A, Kolodziejek J, Nowotny N, Nielsen PF, Conlon JM. Purification and characterization of antimicrobial peptides from the skin secretions of the mink frog Rana septentrionalis. Comp Biochem Physiol 2004; 139C:31-8. Che J, Pang J, Zhao EM, Matsui M, Zhang YP. Phylogenetic relationships of the Chinese brown frogs (genus Rana) inferred from partial mitochondrial 12S and 16S rRNA gene sequences. Zool Sci 2007;24:71-80. Che J, Pang J, Zhao H, Wu GF, Zhao EM, Zhang YP. Phylogeny of Raninae (Anura: Ranidae) inferred from mitochondrial and nuclear sequences. Mol Phylogenet Evol 2007;43:1-13. Clinical Laboratory and Standards Institute. Reference method for broth dilution antifungal susceptibility testing of yeast. Approved Standard M27-A3. CLS1, Wayne, PA, 2008. Conlon JM. Reflections on a systematic nomenclature for antimicrobial peptides from the skins of frogs of the family Ranidae. Peptides 2008;29:1815-9. Conlon J.M., Abraham B, Sonnevend A., Jouenne T., Cosette P., Leprince J., et al. Purification and characterization of antimicrobial peptides from the skin secretions of the carpenter frog Rana virgatipes (Ranidae, Aquarana). Regul Pept 2005;131:38-45. Conlon JM, Kolodziejek J, Nowotny N. Antimicrobial peptides from ranid frogs: taxonomic and phylogenetic markers and a potential source of new therapeutic agents. Biochim Biophys Acta 2004;1696:1-14. Conlon JM, Kolodziejek J, Nowotny N. Antimicrobial peptides from the skins of North American frogs. Biochim Biophys Acta 2009;1788:1556-63. Dijkshoorn L, Nemec A, Seifert H. An increasing threat in hospitals: multidrug-resistant Acinetobacter baumannii. Nat Rev Microbiol 2007;5:939- Frost DR. Amphibian Species of the World: an Online Reference. Version 5.3. Electronic Database accessible at http://research.amnh.org/ herpetology/amphibia/, American Museum of Natural History, New York, USA, 2009. Iwamuro S, Nakamura M, Ohnuma A, Conlon JM. Molecular cloning and sequence analyses of preprotemporin mRNAs containing premature stop codons from extradermal tissues of Rana tagoi. Peptides 2006;27:2124-8. Karageorgopoulos DE, Falagas ME. Current control and treatment of multidrug-resistant Acinetobacter baumannii infections. Lancet Infect Dis 2008;8:751-62. Mangoni ML. Temporins, anti-infective peptides with expanding properties. Cell Mol Life Sci 2006;63:1060-9. Maragakis LL, Perl TM. Acinetobacter baumannii: epidemiology, antimicrobial resistance, and treatment options. Clin Infect Dis 2008;46:1254-63. Morikawa N, Hagiwara K, Nakajima T. Brevinin-1 and -2, unique antimicrobial peptides from the skin of the frog, Rana brevipoda porsa. Biochem Biophys Res Commun 1992;189:184-90. Mechkarska, M., Ahmed, E., Coquet, L., Leprince, J. Jouenne, T., Vaudry, H., King, J., and Conlon, J. Antimicrobial peptides with therapeutic potential from skin secretions of the Marsabit clawed frog Xenopus borealis (Pipidae). Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 2010:152,4: 467-472 Pauly GB, Hillis DM, Cannatella DC. Taxonomic freedom and the role of official lists of species names. Herpetologica 2009;65:115-28. Perez F, Hujer AM, Hujer KM, Decker BK, Rather PN, Bonomo RA. Global challenge of multidrug-resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2007;51:3471-84. Powers JP, Hancock RE. The relationship between peptide structure and antibacterial activity. Peptides 2003;24:1681-91. Rost B, Yachdav G, Liu J.The PredictProtein Server. Nucleic Acids Res 2004;32 (Web Server issue):W321-6. Rinaldi AC, Mangoni ML, Rufo A, Luzi C, Barra D, Zhao H, et al. Temporin L: antimicrobial, haemolytic and cytotoxic activities, and effects on membrane permeabilization in lipid vesicles. Biochem J 2002;368:91-100. Schiffer M, Edmundson AB. Use of helical wheels to represent the structures of proteins and to identify segments with helical potential. Biophys J 1967;7: 121-35. Simmaco M, Mignogna G, Barra D, Bossa F. Antimicrobial peptides from skin secretions of Rana esculenta. Molecular cloning of cDNAs encoding esculentin and brevinins and isolation of new active peptides. J. Biol. Chem. 1994;269: 11956-61. Suzuki H, Iwamuro S, Ohnuma A, Coquet L, Leprince J, Jouenne T, et al. Expression of genes encoding antimicrobial and bradykinin-related peptides in skin of the stream brown frog Rana sakuraii. Peptides 2007;28:505-14. Tanaka T, Matsui M, Takenaka O. Phylogenetic relationships of Japanese brown frogs (Rana: Ranidae) assessed by mitochondrial cytochrome b gene sequences. Biochem Syst Ecol 1996;24:299-307. Wang H, Yan X, Yu H, Hu Y, Yu Z, Zheng H, et al. Isolation, characterization and molecular cloning of new antimicrobial peptides belonging to the brevinin-and temporin families from the skin of Hylarana latouchii (Anura: Ranidae). Biochimie 2009;91:540-7. Zhou J, McClean S, Thompson A, Zhang Y, Shaw C, Rao P, Bjourson AJ. Purification and characterization of novel antimicrobial peptides from the skin secretion of Hylarana guentheri. Peptides 2006;27:3077-84. Read More