Broad-Spectrum Antimicrobial Activity and Low Cytotoxicity against Human Cells of a Peptide Derived from Bovine αS1-Casein

The primary objective of this study was to improve our understanding of the antimicrobial mechanism of protein-derived peptides and to provide evidence for protein-derived peptides as food bio-preservatives by examining the antimicrobial activities, low cytotoxicity, stabilities, and mechanism of Cp1 (LRLKKYKVPQL). In this study, the protein-derived peptide Cp1 was synthesized from bovine αS1-casein, and its potential use as a food biopreservative was indicated by the higher cell selectivity shown by 11-residue peptide towards bacterial cells than human RBCs. It also showed broad-spectrum antimicrobial activity, with minimum inhibitory concentrations (MICs) of 64–640 μM against both gram-positive and gram-negative bacteria. The peptide had low hemolytic activity (23.54%, 512 μM) as well as cytotoxicity. The results of fluorescence spectroscopy, flow cytometry, and electron microscopy experiments indicated that Cp1 exerted its activity by permeabilizing the microbial membrane and destroying cell membrane integrity. We found that Cp1 had broad-spectrum antimicrobial activity, low hemolytic activity, and cytotoxicity. The results also revealed that Cp1 could cause cell death by permeabilizing the cell membrane and disrupting membrane integrity. Overall, the findings presented in this study improve our understanding of the antimicrobial potency of Cp1 and provided evidence of the antimicrobial mechanisms of Cp1. The peptide Cp1 could have potential applications as a food biopreservative

Antibacterial Activity and Mechanism of Action of Bovine Lactoferricin Derivatives with Symmetrical Amino Acid Sequences

In recent years, the overuse of antibiotics has become very serious. Many pathogenic bacteria have become resistant to them, with serious potential health consequences. Thus, it is urgent that we develop new antibiotic drugs. Antimicrobial peptides (AMPs) are important endogenous antibacterial molecules that contribute to immunity. Most have spectral antibacterial properties and do not confer drug resistance. In this paper, an 11-residue peptide (LFcinB18–28) with a sequence of KCRRWQWRMKK was modified by amino acid substitution to form a symmetrical amino acid sequence. The antibacterial activities and mechanisms of action of engineered peptides including KW-WK (KWRRWQWRRWK), FP-PF (FPRRWQWRRPF), FW-WF (FWRRWQWRRWF), and KK-KK (KKRRWQWRRKK) were investigated. The four engineered peptides could more effectively inhibit bacteria than the original peptide, LFcinB18–28. This suggested that a symmetrical amino acid sequence might enhance the antibacterial activity of AMPs. However, only peptides KW-WK, FP-PF, and KK-KK were safe; FW-WF displayed hemolytic activity. The engineered peptides shared cationic and amphipathic characteristics that facilitated interactions with the anionic microbial membranes, leading to disruption of membrane integrity and permeabilizing microbial membranes, resulting in cell death. Therefore, a symmetrical amino acid sequence and related structural parameters offer an alternative approach to the design of AMPs. This will provide a scientific basis for the design and synthesis of new AMPs

Correction to: A novel protein derived from lamprey supraneural body tissue with efficient cytocidal actions against tumor cells

Correction Unfortunately, following publication of this article [1], it was noticed that the key in Figure 5c incorrectly showed ‘0 h’, ‘5 h’ and ‘10 h’. The corrected version, showing ‘0 h’, ‘12 h’ and ‘24 h’, can be seen below and the original article has been updated to reflect this

A novel protein derived from lamprey supraneural body tissue with efficient cytocidal actions against tumor cells

Abstract Background In previous research, we found that cell secretion from the adult lamprey supraneural body tissues possesses cytocidal activity against tumor cells, but the protein with cytocidal activity was unidentified. Methods A novel lamprey immune protein (LIP) as defense molecule was first purified and identified in jawless vertebrates (cyclostomes) using hydroxyapatite column and Q Sepharose Fast Flow column. After LIP stimulation, morphological changes of tumor cells were analysed and measured whether in vivo or in vitro. Results LIP induces remarkable morphological changes in tumor cells, including cell blebbing, cytoskeletal alterations, mitochondrial fragmentation and endoplasmic reticulum vacuolation, and most of the cytoplasmic and organelle proteins are released following treatment with LIP. LIP evokes an elevation of intracellular calcium and inflammatory molecule levels. Our analysis of the cytotoxic mechanism suggests that LIP can upregulate the expression of caspase 1, RIPK1, RIP3 to trigger pyroptosis and necroptosis. To examine the effect of LIP in vivo, tumor xenograft experiments were performed, and the results indicated that LIP inhibits tumor growth without damage to mice. In addition, the cytotoxic action of LIP depended on the phosphatidylserine (PS) content of the cell membrane. Conclusions These observations suggest that LIP plays a crucial role in tumor cell survival and growth. The findings will also help to elucidate the mechanisms of host defense in lamprey

Additional file 1: Figure S1. of A novel protein derived from lamprey supraneural body tissue with efficient cytocidal actions against tumor cells

The construction and expression of pColdI-rLi protein plasmid. (a) The construction of pColdI-rLIP plasmid. M, DL10000 Marker; 1, pColdTMIDNA; 2, pColdTMIDNA (BamH Ι/Hind III); 3, PCR products of rLIP; 4, rLi protein(BamH Ι/Hind III); 5, pColdI-rLIP; 6, Double digestion products of pColdI-rLIP. (b) Total protein was separated by 12% SDS-PAGE under reducing conditions and stained with Coomassie Brilliant Blue R-250. Lane M, low molecular weight protein maker; Lane 1, crude lysate pre-induction; Lane 2, crude lysate post-induction; Lane 3, purified LIP. (PDF 234 kb

Le Monde

29 juillet 18681868/07/29 (N206,A9).Appartient à l’ensemble documentaire : BbLevt