scholarly journals Molecular Characterization and Phylogenetic Analysis of a Histone-Derived Antimicrobial Peptide Teleostin from the Marine Teleost Fishes, Tachysurus jella and Cynoglossus semifasciatus

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
E. R. Chaithanya ◽  
Rosamma Philip ◽  
Naveen Sathyan ◽  
P. R. Anil Kumar
Keyword(s):  
Amino Acids ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Defense Mechanism ◽  
Peptide Sequence ◽  
Teleost Fishes ◽  
Marine Teleost ◽  
Histone H2a ◽  
Host Defense Peptides ◽  
Innate Defense

Antimicrobial peptides (AMPs) are host defense peptides that are well conserved throughout the course of evolution. Histones are classical DNA-binding proteins, rich in cationic amino acids, and recently appreciated as precursors for various histone-derived AMPs. The present study deals with identification of the potential antimicrobial peptide sequence of teleostin from the histone H2A of marine teleost fishes, Cynoglossus semifasciatus and Tachysurus jella. A 245 bp amplicon coding for 81 amino acids was obtained from the cDNA transcripts of these fishes. The first 52 amino acids from the N terminal of the peptide were identical to previously characterized histone-derived antimicrobial peptides. Molecular and physicochemical characterizations of the sequence were found to be in agreement with previously reported histone H2A-derived AMPs, suggesting the possible role of histone H2A in innate defense mechanism in fishes.

scholarly journals Analysis of structures, functions, and transgenicity of phytopeptides defensin and thionin: a review

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Sarfuddin Azmi ◽  
Mohd Kamil Hussain
Keyword(s):  
Transgenic Plants ◽  
Antimicrobial Peptides ◽  
Defense Mechanism ◽  
Functional Characterization ◽  
Harmful Effect ◽  
Intrinsic Property ◽  
Pathogenic Fungi ◽  
Biotic And Abiotic Stress ◽  
Good Efficiency ◽  
Innate Defense

Abstract Background Antimicrobial peptides are very primitive innate defense molecules of almost all organisms, from microbes to mammalians and vascular seed-bearing plants. Antimicrobial peptides of plants categorized into cysteine-rich peptides (CRPs) and others and most of the antimicrobial peptides belong to CRPs group. These peptides reported showing the great extent of protecting property against bacteria, fungi, viruses, insect, nematode, and another kind of microbes. To develop a resistant plant against pathogenic fungi, there have been several studies executed to understand the efficiency of transgenicity of these antimicrobial peptides. Main text Apart from the intrinsic property of the higher organism for identifying and activating microbial attack defense device, it also involves innate defense mechanism and molecules. In the current review article, apart from the structural and functional characterization of peptides defensin and thionin, we have attempted to provide a succinct overview of the transgenic development of these defense peptides, that are expressed in a constitutive and or over-expressive manner when biotic and abiotic stress inflicted. Transgenic of different peptides show different competence in plants. Most of the transgenic studies made for defensin and thionin revealed the effective transgenic capacity of these peptides. Conclusion There have been several studies reported successful development of transgenic plants based on peptides defensin and thionin and observed diverse level of resistance-conferring potency in different plants against phytopathogenic fungi. But due to long regulatory process, there has not been marketed any antimicrobial peptides based transgenic plants yet. However, success report state that possibly in near future transgenic plants of AMPs would be released with devoid of harmful effect, with good efficiency, reproducibility, stability, and least production cost.

scholarly journals SSD1 Is Integral to Host Defense Peptide Resistance in Candida albicans

2008 ◽  
Vol 7 (8) ◽  
pp. 1318-1327 ◽  
Author(s):  
Kimberly D. Gank ◽  
Michael R. Yeaman ◽  
Satoshi Kojima ◽  
Nannette Y. Yount ◽  
Hyunsook Park ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Host Defense ◽  
Genomic Library ◽  
Inflammatory Responses ◽  
Host Defense Peptides ◽  
Antimicrobial Peptide Resistance ◽  
Null Mutants

ABSTRACT Candida albicans is usually a harmless human commensal. Because inflammatory responses are not normally induced by colonization, antimicrobial peptides are likely integral to first-line host defense against invasive candidiasis. Thus, C. albicans must have mechanisms to tolerate or circumvent molecular effectors of innate immunity and thereby colonize human tissues. Prior studies demonstrated that an antimicrobial peptide-resistant strain of C. albicans, 36082R, is hypervirulent in animal models versus its susceptible counterpart (36082S). The current study aimed to identify a genetic basis for antimicrobial peptide resistance in C. albicans. Screening of a C. albicans genomic library identified SSD1 as capable of conferring peptide resistance to a susceptible surrogate, Saccharomyces cerevisiae. Sequencing confirmed that the predicted translation products of 36082S and 36082R SSD1 genes were identical. However, Northern analyses corroborated that SSD1 is expressed at higher levels in 36082R than in 36082S. In isogenic backgrounds, ssd1Δ/ssd1Δ null mutants were significantly more susceptible to antimicrobial peptides than parental strains but had equivalent susceptibilities to nonpeptide stressors. Moreover, SSD1 complementation of ssd1Δ/ssd1Δ mutants restored parental antimicrobial peptide resistance phenotypes, and overexpression of SSD1 conferred enhanced peptide resistance. Consistent with these in vitro findings, ssd1 null mutants were significantly less virulent in a murine model of disseminated candidiasis than were their parental or complemented strains. Collectively, these results indicate that SSD1 is integral to C. albicans resistance to host defense peptides, a phenotype that appears to enhance the virulence of this organism in vivo.

scholarly journals Structure-Activity Relationship of Synthetic Variants of the Milk-Derived Antimicrobial Peptide αs2-Casein f(183–207)

2013 ◽  
Vol 79 (17) ◽  
pp. 5179-5185 ◽  
Author(s):  
Avelino Alvarez-Ordóñez ◽  
Máire Begley ◽  
Tanya Clifford ◽  
Thérèse Deasy ◽  
Kiera Considine ◽  
...  
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Amino Acid ◽  
Antimicrobial Peptide ◽  
Peptide Sequence ◽  
Content Type ◽  
Charged Amino Acids ◽  
Food Borne ◽  
Relationship Of ◽  
Positively Charged

ABSTRACTTemplate-based studies on antimicrobial peptide (AMP) derivatives obtained through manipulation of the amino acid sequence are helpful to identify properties or residues that are important for biological activity. The present study sheds light on the importance of specific amino acids of the milk-derived αs2-casein f(183–207) peptide to its antibacterial activity against the food-borne pathogensListeria monocytogenesandCronobacter sakazakii. Trimming of the peptide revealed that residues at the C-terminal end of the peptide are important for activity. Removal of the last 5 amino acids at the C-terminal end and replacement of the Arg at position 23 of the peptide sequence by an Ala residue significantly decreased activity. These findings suggest that Arg23 is very important for optimal activity of the peptide. Substitution of the also positively charged Lys residues at positions 15 and 17 of the αs2-casein f(183–207) peptide also caused a significant reduction of the effectiveness againstC. sakazakii, which points toward the importance of the positive charge of the peptide for its biological activity. Indeed, simultaneous replacement of various positively charged amino acids was linked to a loss of bactericidal activity. On the other hand, replacement of Pro residues at positions 14 and 20 resulted in a significantly increased antibacterial potency, and hydrophobic end tagging of αs2-casein f(193–203) and αs2-casein f(197–207) peptides with multiple Trp or Phe residues significantly increased their potency againstL. monocytogenes. Finally, the effect of pH (4.5 to 7.4), temperature (4°C to 37°C), and addition of sodium and calcium salts (1% to 3%) on the activity of the 15-amino-acid αs2-casein f(193–207) peptide was also determined, and its biological activity was shown to be completely abolished in high-saline environments.

scholarly journals Key Residues of Outer Membrane Protein OprI Involved in Hexamer Formation and Bacterial Susceptibility to Cationic Antimicrobial Peptides

2015 ◽  
Vol 59 (10) ◽  
pp. 6210-6222 ◽  
Author(s):  
Ting-Wei Chang ◽  
Chiu-Feng Wang ◽  
Hsin-Jye Huang ◽  
Iren Wang ◽  
Shang-Te Danny Hsu ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Antimicrobial Peptides ◽  
Outer Membrane ◽  
Conformational Changes ◽  
Outer Membrane Protein ◽  
Defense Mechanism ◽  
Vital Role ◽  
Content Type ◽  
Innate Defense ◽  
Link Type

ABSTRACTAntimicrobial peptides (AMPs) are important components of the host innate defense mechanism against invading pathogens. Our previous studies have shown that the outer membrane protein, OprI fromPseudomonas aeruginosaor its homologue, plays a vital role in the susceptibility of Gram-negative bacteria to cationic α-helical AMPs (Y. M. Lin, S. J. Wu, T. W. Chang, C. F. Wang, C. S. Suen, M. J. Hwang, M. D. Chang, Y. T. Chen, Y. D. Liao, J Biol Chem 285:8985–8994, 2010,http://dx.doi.org/10.1074/jbc.M109.078725; T. W. Chang, Y. M. Lin, C. F. Wang, Y. D. Liao, J Biol Chem287:418–428, 2012,http://dx.doi.org/10.1074/jbc.M111.290361). Here, we obtained two forms of recombinant OprI: rOprI-F, a hexamer composed of three disulfide-bridged dimers, was active in AMP binding, while rOprI-R, a trimer, was not. All the subunits predominantly consisted of α-helices and exhibited rigid structures with a melting point centered around 76°C. Interestingly, OprI tagged withEscherichia colisignal peptide was expressed in a hexamer, which was anchored on the surface ofE. coli, possibly through lipid acids added at the N terminus of OprI and involved in the binding and susceptibility to AMP as nativeP. aeruginosaOprI. Deletion and mutation studies showed that Cys1 and Asp27 played a key role in hexamer formation and AMP binding, respectively. The increase of OprI hydrophobicity upon AMP binding revealed that it undergoes conformational changes for membrane fusion. Our results showed that OprI on bacterial surfaces is responsible for the recruitment and susceptibility to amphipathic α-helical AMPs and may be used to screen antimicrobials.

scholarly journals Antimicrobial Peptides and How to Find Them

2021 ◽  
Vol 9 ◽  
Author(s):  
Barbara Spellerberg ◽  
Ludger Ständker ◽  
Rüdiger Groß ◽  
Jan Münch
Keyword(s):  
Amino Acids ◽  
Immune System ◽  
Antiviral Activity ◽  
Antimicrobial Peptides ◽  
Human Body ◽  
Bacterial Cell ◽  
Defense Mechanism ◽  
Peptide Libraries ◽  
Antimicrobial Substances ◽  
Mucous Membranes

Bacteria and viruses may enter our bodies through mucous membranes of the airways or the gut. To prevent infections, one defense mechanism of our immune system is antimicrobial peptides (AMPs). Most AMPs are composed of 10–50 amino acids and insert into bacterial cell membranes to destroy the cell. Some AMPs are also active against viruses and fungi. AMPs can be generated by chopping up bigger proteins like hemoglobin. The hemoglobin fragments can inactivate bacteria and viruses, while the whole hemoglobin protein cannot. To identify new AMPs, peptide libraries consisting of thousands of different peptides can be generated from human body fluids and organs. These libraries are tested for antibacterial or antiviral activity and can be further purified to identify the responsible peptide. This method may lead to the development of new antimicrobial substances with a potential for treating infections.

scholarly journals Role of antimicrobial peptides in periodontal innate defense mechanism

2015 ◽  
Vol 7 (2) ◽  
pp. 74 ◽  
Author(s):  
Ashank Mishra ◽  
Bagalkotkr Apeksha ◽  
Pradeep Koppolu ◽  
SwapnaAmara Lingam
Keyword(s):  
Antimicrobial Peptides ◽  
Defense Mechanism ◽  
Innate Defense

scholarly journals Bcr1 Functions Downstream of Ssd1 To Mediate Antimicrobial Peptide Resistance in Candida albicans

2013 ◽  
Vol 12 (3) ◽  
pp. 411-419 ◽  
Author(s):  
Sook-In Jung ◽  
Jonathan S. Finkel ◽  
Norma V. Solis ◽  
Siyang Chaili ◽  
Aaron P. Mitchell ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Target Genes ◽  
Regulatory Protein ◽  
Homozygous Deletion ◽  
Plasma Membrane Permeability ◽  
Host Defense Peptides ◽  
Content Type ◽  
Antimicrobial Peptide Resistance

ABSTRACTIn order to colonize the host and cause disease,Candida albicansmust avoid being killed by host defense peptides. Previously, we determined that the regulatory protein Ssd1 governs antimicrobial peptide resistance inC. albicans. Here, we sought to identify additional genes whose products govern susceptibility to antimicrobial peptides. We discovered that abcr1Δ/Δ mutant, like thessd1Δ/Δ mutant, had increased susceptibility to the antimicrobial peptides, protamine, RP-1, and human β defensin-2. Homozygous deletion ofBCR1in thessd1Δ/Δ mutant did not result in a further increase in antimicrobial peptide susceptibility. Exposure of thebcr1Δ/Δ andssd1Δ/Δ mutants to RP-1 induced greater loss of mitochondrial membrane potential and increased plasma membrane permeability than with the control strains. Therefore, Bcr1 and Ssd1 govern antimicrobial peptide susceptibility and likely function in the same pathway. Furthermore,BCR1mRNA expression was downregulated in thessd1Δ/Δ mutant, and the forced expression ofBCR1in thessd1Δ/Δ mutant partially restored antimicrobial peptide resistance. These results suggest that Bcr1 functions downstream of Ssd1. Interestingly, overexpression of 11 known Bcr1 target genes in thebcr1Δ/Δ mutant failed to restore antimicrobial peptide resistance, suggesting that other Bcr1 target genes are likely responsible for antimicrobial peptide resistance. Collectively, these results demonstrate that Bcr1 functions downstream of Ssd1 to govern antimicrobial peptide resistance by maintaining mitochondrial energetics and reducing membrane permeabilization.

Antimicrobial Peptides: A Promising Avenue for Human Healthcare

2020 ◽  
Vol 21 (2) ◽  
pp. 90-96 ◽  
Author(s):  
Girish M. Bhopale
Keyword(s):  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Antimicrobial Agents ◽  
Current Status ◽  
Antimicrobial Drugs ◽  
Spectrum Activity ◽  
Low Levels ◽  
Human Healthcare ◽  
Broad Spectrum Activity ◽  
Promising Avenue

Antimicrobial drugs resistant microbes have been observed worldwide and therefore alternative development of antimicrobial peptides has gained interest in human healthcare. Enormous progress has been made in the development of antimicrobial peptide during the last decade due to major advantages of AMPs such as broad-spectrum activity and low levels of induced resistance over the current antimicrobial agents. This review briefly provides various categories of AMP, their physicochemical properties and mechanism of action which governs their penetration into microbial cell. Further, the recent information on current status of antimicrobial peptide development, their applications and perspective in human healthcare are also described.

Isoleucine Plays an Important Role for Maintaining Immune Function

2019 ◽  
Vol 20 (7) ◽  
pp. 644-651 ◽  
Author(s):  
Changsong Gu ◽  
Xiangbing Mao ◽  
Daiwen Chen ◽  
Bing Yu ◽  
Qing Yang
Keyword(s):  
Amino Acids ◽  
Acid Metabolism ◽  
Branched Chain Amino Acids ◽  
Whole Body ◽  
Immune Functions ◽  
Host Defense Peptides ◽  
Innate And Adaptive Immunity ◽  
Physiological Functions ◽  
Branched Chain ◽  
The Relationship

Branched chain amino acids are the essential nutrients for humans and many animals. As functional amino acids, they play important roles in physiological functions, including immune functions. Isoleucine, as one of the branched chain amino acids, is also critical in physiological functions of the whole body, such as growth, immunity, protein metabolism, fatty acid metabolism and glucose transportation. Isoleucine can improve the immune system, including immune organs, cells and reactive substances. Recent studies have also shown that isoleucine may induce the expression of host defense peptides (i.e., β-defensins) that can regulate host innate and adaptive immunity. In addition, isoleucine administration can restore the effect of some pathogens on the health of humans and animals via increasing the expression of β-defensins. Therefore, the present review will emphatically discuss the effect of isoleucine on immunity while summarizing the relationship between branched chain amino acids and immune functions.

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