The peptide had a positive charge + 2 and was made up of 60% hydrophobic amino acids. It displayed a broad-spectrum antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, and fungi. subtilis was the most sensitive to the peptide at a minimal inhibition concentration of 2 μg/mL.
Results revealed acidic extracts were active against both Gram-positive and Gram-negative bacteria in conditions that likely mimicked the natural environment of cod. This suggests that the skin mucus layer of the Atlantic cod is an important tissue in surface defenses of cod and most likely protects the fish from infections caused by pathogenic microbes. Antimicrobial test results revealed Bacillus megaterium as the most sensitive to the extract at all concentrations of NaCl. Antimicrobial peptides were identified as histone H2B and ribosomal proteins L40, L36A, and L35. Histone-derived peptides originate from both the N-terminus and C-terminus of H1, H2A, H2B, and H6 histones. These histone peptides are found in the skin, skin mucus, and other tissues, including gills, the spleen, and the gut. They are produced in response to epidermal damage, LPS, or certain Gram-negative bacteria.
Their antimicrobial activity is broad spectrum against both human and fish pathogens Gram-positive and Gram-negative bacteria, parasites, and fungi. Aside from hydrolysates, AMPs have also been successfully isolated from fish skin mucus as well. The antimicrobial activity of yellow catfish skin mucus was investigated, and a novel peptide GKLNLFLSRLEILKLFVGAL was identified and named pelteobagrin.
Typically the peptide Aβ elements can aggregate to be able to form flexible resoluble oligomers, some regarding which turn out misfolded. These misfolded oligomers can induce other Aβ molecules to also take the misfolded oligomeric form (Haass and Selkoe 2007; Nussbaum et al. 2013; Pulawski et al. 2012). Anti-Alzheimer’s and neuroprotective activity of fish skin hydrolysates is summarized in Table4.
The enzyme β-secretase in addition to another chemical ϒ-secretase generate a new peptide amyloid-β (Aβ) through endo-proteolytic side effects in the amyloid progenitor protein. Apolipoprotein boosts the breakdown regarding beta-amyloid; yet , a great isoform of apolipoprotein, APOE4, ineffectively complete breakdowns beta-amyloid and qualified prospects to an excessive amyloid buildup inside the brain.
A β-secretase inhibitor peptide was purified from skate skin hydrolysate (Lee et al. 2015). The peptide was purified from a neutrase hydrolysate of skate skin on a Sephadex G-25 column and with reversed-phase HPLC. The peptide sequence was determined to be QGYRPLRGPEFL and showed β-secretase inhibitory activity with an IC50 value of 24. 26 μM. The neuroprotective effect of protein hydrolysates with antioxidant activity from grass carp skin was demonstrated (Cai et al. 2015). The hydrolysates at the degree of hydrolysis DH5, DH10, and DH15 showed the most significant neuroprotective effect on 6-OHDA-induced neurotoxicity in MES 23. 5. Salmon skin enzymatic hydrolysate showed learning and memory enhancement in mice (Pei et al. 2010).
Oxidative stress was alleviated, apoptotic neurons reduced, and brain-derived neurotrophic factor expression was upregulated in treatment groups compared with the control group. A study by Bergsson investigated antimicrobial components from the skin mucus of healthy Atlantic cod (Bergsson et al. 2005).
The peptide demonstrated no hemolytic activity against rabbit red blood cells, and it was relatively salt tolerant to concentrations of NaCl up to 137 mM. Similarly, a novel peptide from skin mucous secretions of the winter flounder was purified and characterized (Cole et al. 1997). เกมยิงปลา jili The peptide was named pleurocidin, and it had a protein sequence of GWGSFFKKAAHVGKHVGKAALTHYL. It exhibited a broad-spectrum activity against a wide range of Gram-positive and Gram-negative bacteria. subtilis was the most sensitive to the peptide with a MIC value of 1 . 1–2. 2 μM.