A potent and structurally novel antimicrobial peptide was isolated and characterized from the stomach tissue of Bufo bufo gargarizans, an Asian toad. The 39-amino acid peptide, named buforin I, was purified to homogeneity by heparin-affinity column and reverse-phase HPLC. The amino acid sequence of buforin I was identical in 37 of 39 amino-terminal residues of Xenopus histone H2A. The buforin I showed strong antimicrobial activities in vitro against a broad-spectrum of microorganisms and was found to be more potent than magainin 2. In addition, a 21-amino acid peptide, named buforin II, which was derived from buforin I, showed more potent antimicrobial activities than buforin I.

Isolation and characterization of a novel antimicrobial peptide from Bufo bufo gargarizans = 한국산 두꺼비로부터 새로운 항균 펩타이드 분리와 그 특성 연구

With advancements in genomics, there has been substantial reduction in the cost and time of genome sequencing and has resulted in lot of data in genome databases. Antimicrobial host defense proteins provide protection against invading microbes. But confirming the antimicrobial function of host proteins by wet-lab experiments is expensive and time consuming. Therefore, there is a need to develop an in silico tool to identify the antimicrobial function of proteins. In the current study, we developed a model AniAMPpred by considering all the available antimicrobial peptides (AMPs) of length $\in $[10 200] from the animal kingdom. The model utilizes a support vector machine algorithm with deep learning-based features and identifies probable antimicrobial proteins (PAPs) in the genome of animals. The results show that our proposed model outperforms other state-of-the-art classifiers, has very high confidence in its predictions, is not biased and can classify both AMPs and non-AMPs for a diverse peptide length with high accuracy. By utilizing AniAMPpred, we identified 436 PAPs in the genome of Helobdella robusta. To further confirm the functional activity of PAPs, we performed BLAST analysis against known AMPs. On detailed analysis of five selected PAPs, we could observe their similarity with antimicrobial proteins of several animal species. Thus, our proposed model can help the researchers identify PAPs in the genome of animals and provide insight into the functional identity of different proteins. An online prediction server is also developed based on the proposed approach, which is freely accessible at https://aniamppred.anvil.app/.

AniAMPpred: artificial intelligence guided discovery of novel antimicrobial peptides in animal kingdom.

Marine organisms have been shown to be a valuable source for biologically active compounds for the prevention and treatment of cancer, inflammation, immune system diseases, and other pathologies. The advantage of studying organisms collected in the marine environment lies in their great biodiversity and in the variety of chemical structures of marine natural products. Various studies have focused on marine organism compounds with potential pharmaceutical applications, for instance, as immunomodulators, to treat cancer and immune-mediated diseases. Modulation of the immune system is defined as any change in the immune response that can result in the induction, expression, amplification, or inhibition of any phase of the immune response. Studies very often focus on the effects of marine-derived compounds on macrophages, as well as lymphocytes, by analyzing the release of mediators (cytokines) by using the immunological assay enzyme-linked immunosorbent assay (ELISA), Western blot, immunofluorescence, and real-time PCR. The main sources are fungi, bacteria, microalgae, macroalgae, sponges, mollusks, corals, and fishes. This review is focused on the marine-derived molecules discovered in the last three years as potential immunomodulatory drugs.

/pdf/recent-discoveries-on-marine-organism-immunomodulatory-ca0l0gk5.pdf

Recent Discoveries on Marine Organism Immunomodulatory Activities

Host defense peptides (HDPs) are gaining increasing interest, since they are endowed with multiple activities, are often effective on multidrug resistant bacteria and do not generally lead to the development of resistance phenotypes. Cryptic HDPs have been recently identified in human apolipoprotein B and found to be endowed with a broad-spectrum antimicrobial activity, with anti-biofilm, wound healing and immunomodulatory properties, and with the ability to synergistically act in combination with conventional antibiotics, while being not toxic for eukaryotic cells. Here, a multidisciplinary approach was used, including time killing curves, differential scanning calorimetry, circular dichroism, ThT binding assays, and transmission electron microscopy analyses. The effects of a single point mutation (Pro → Ala in position 7) on the biological properties of ApoB-derived peptide r(P)ApoBLPro have been evaluated. Although the two versions of the peptide share similar antimicrobial and anti-biofilm properties, only r(P)ApoBLAla peptide was found to exert bactericidal effects. Interestingly, antimicrobial activity of both peptide versions appears to be dependent from their interaction with specific components of bacterial surfaces, such as LPS or LTA, which induce peptides to form β-sheet-rich amyloid-like structures. Altogether, obtained data indicate a correlation between ApoB-derived peptides self-assembling state and their antibacterial activity.

https://www.mdpi.com/1424-8247/14/7/631/pdf

Impact of a Single Point Mutation on the Antimicrobial and Fibrillogenic Properties of Cryptides from Human Apolipoprotein B.

Identification of three novel Spätzle genes in Eriocheir sinensis and their roles during white spot syndrome virus infection.

Antimicrobial peptides (AMPs) are biologically dynamic molecules produced by all type of organisms as a fundamental component of their innate immune system. The present study deals with the identification of a histone H2A-derived antimicrobial peptide, Hipposin from mangrove whip ray, Himantura walga. A 243 base pair fragment encoding 81 amino acid residues amplified from complementary DNA was identified as Hipposin and termed as Hw-Hip. Homologous analysis showed that Hw-Hip belongs to the Histone H2A superfamily and shares sequence identity with other histone-derived AMPs from fishes. Phylogenetic analysis of Hw-Hip displayed clustering with the fish H2A histones. Secondary structure analysis showed the presence of three α-helices and four random coils with a prominent proline hinge. The physicochemical properties of Hw-Hip are in agreement with the properties of antimicrobial peptides. A 39-mer active peptide sequence was released by proteolytic cleavage in silico. Functional characterisation of active peptide in silico revealed antibacterial, anticancer and antibiofilm activities making Hw-Hip a promising candidate for further exploration.

A histone H2A-derived antimicrobial peptide, Hipposin from mangrove whip ray, Himantura walga: Molecular and functional characterisation

/pdf/a-hepatic-antimicrobial-peptide-hepcidin-from-indian-major-1jy1p14s.pdf

A hepatic antimicrobial peptide, hepcidin from Indian major carp, Catla catla: molecular identification and functional characterization

Structural, functional and phylogenetic analysis of a beta defensin gene from the Whipfin silverbiddy, Gerres filamentosus (Cuvier, 1829)

Anti-lipopolysaccharide factors (ALFs) are antimicrobial peptides of approximately 100 amino acid residues with a broad spectrum of antimicrobial activity It is an amphipathic peptide with an N-terminal hydrophobic region and a lipopolysaccharide binding domain (LBD) In the present study, we report an isoform of the anti-lipopolysaccharide factor (Mm-ALF) from the speckled shrimp, Metapenaeus monoceros A 359 bp cDNA encoded 119 amino acids, and the sequence showed 9916% similarity to ALF from the shrimp Fenneropenaeus indicus The mature peptide of 94 amino acids has a net charge of +8, molecular weight 1062 kDa, and pI 1011 The mature peptide Mm-ALF was recombinantly expressed in E coli Rosetta-gami cells, and the peptide was isolated and purified The rMm-ALF exhibited notable antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Escherichia coli, Edwardsiella tarda, Aeromonas hydrophila, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Vibrio harveyi, Vibrio alginolyticus, Vibrio proteolyticus, Vibrio cholerae and Vibrio fluvialis) bacteria

Molecular and Functional Characterization of an Anti-lipopolysaccharide Factor Mm-ALF from Speckled Shrimp Metapenaeus monoceros

https://link.springer.com/content/pdf/10.1186/s43141-021-00175-6.pdf

M.V. Anju

Papers

A histone H2A-derived antimicrobial peptide, Hipposin from mangrove whip ray, Himantura walga: Molecular and functional characterisation

A hepatic antimicrobial peptide, hepcidin from Indian major carp, Catla catla: molecular identification and functional characterization

Structural, functional and phylogenetic analysis of a beta defensin gene from the Whipfin silverbiddy, Gerres filamentosus (Cuvier, 1829)

Molecular and Functional Characterization of an Anti-lipopolysaccharide Factor Mm-ALF from Speckled Shrimp Metapenaeus monoceros

Molecular characterization of a novel β-defensin isoform from the red-toothed trigger fish, Odonus niger (Ruppel, 1836).