Antifungal Synergy: Mechanistic Insights into the R-1-R Peptide and Extract as Potent Therapeutics against spp. through Proteomics.

Previous reports have demonstrated that the peptide derived from LfcinB, R-1-R, exhibits anti- activity, which is enhanced when combined with an extract from the plant. However, the mechanism of action remains unexplored. In this research, a proteomic study was carried out, followed by a bioinformatic analysis and biological assays in both the SC5314 strain and a fluconazole-resistant isolate of after incubation with R-1-R.

In-house standards derived from doping peptides: Enzymatic and serum stability and degradation profile of GHRP and GHRH-related peptides.

Matrix effect and sample pretreatment significantly affect the percentage recovery of peptides in biological matrices, affecting the method robustness and accuracy. To counteract this effect, an internal standard (IS) is used; however, in most cases this is not available, which limits the analytical method. It is important to identify short peptides that can be used as ISs in the quantification of peptides in biological matrices.

Combining the Peptide RWQWRWQWR and an Ethanolic Extract of Enhances the Activity against Sensitive and Resistant and Strains.

The antifungal activity of palindromic peptide RWQWRWQWR and its derivatives was evaluated against clinical isolates of and . Also, ethanolic extracts of leaves and stem were evaluated. Furthermore, combinations of peptide, extract, and/or fluconazole (FLC) were evaluated.

Non-natural amino acids into LfcinB-derived peptides: effect in their (i) proteolytic degradation and (ii) cytotoxic activity against cancer cells.

The dimeric peptide [F]: (RRWQWRKKLG)-K-Ahx has exhibited a potent cytotoxic effect against breast cancer cell lines, with position 26 (F) being the most relevant for anti-cancer activity. In this investigation, six analogues of the [F] peptide were synthesized in which the 26th position was replaced by non-natural hydrophobic amino acids, finding that some modifications increased the resistance to proteolytic degradation exerted by trypsin or pepsin. Additionally, these modifications increased the cytotoxic effect against breast cancer cells and generated cell death mediated by apoptosis pathways, activating caspases 8 and 9, and did not compromise the integrity of the cytoplasmic membrane.

Peptide-Resorcinarene Conjugates Obtained via Click Chemistry: Synthesis and Antimicrobial Activity.

Antimicrobial resistance (AMR) is one of the top ten threats to public health, as reported by the World Health Organization (WHO). One of the causes of the growing AMR problem is the lack of new therapies and/or treatment agents; consequently, many infectious diseases could become uncontrollable. The need to discover new antimicrobial agents that are alternatives to the existing ones and that allow mitigating this problem has increased, due to the rapid and global expansion of AMR.

Changes in Length and Positive Charge of Palindromic Sequence RWQWRWQWR Enhance Cytotoxic Activity against Breast Cancer Cell Lines.

Breast cancer is one of the main causes of premature death in women; current treatments have low selectivity, generating strong physical and psychological sequelae. The palindromic peptide R-1-R (RWQWRWQWR) has cytotoxic activity against different cell lines derived from cancer and selectivity against noncancerous cells. To determine if changes in the charge/length of this peptide increase its activity, six peptides were obtained by SPPS, three of them with addition of Arg at the N, C-terminal or both and three with deletion of Arg at the N, C-terminal or both.

In Vitro Antifungal Activity of Chimeric Peptides Derived from Bovine Lactoferricin and Buforin II against var. .

Cryptococcosis is associated with high rates of morbidity and mortality. The limited number of antifungal agents, their toxicity, and the difficulty of these molecules in crossing the blood-brain barrier have made the exploration of new therapeutic candidates against a priority task. To optimize the antimicrobial functionality and improve the physicochemical properties of AMPs, chemical strategies include combinations of peptide fragments into one.

Gradient Retention Factor Concept Applied to Method Development for Peptide Analysis by Means of RP-HPLC.

Using the van Deemter model, the efficiency of three stationary phase systems in the analysis of a mixture of synthetic peptides was evaluated: (i) monolithic, (ii) packed, and (iii) core-shell columns, and it was shown that the efficiency of the monolithic column is superior to the others, specifically using it, the lowest values of (0.03 and 0.1 mm) were obtained, and additionally its efficiency was not significantly affected by increasing the flow.

Chimeric Peptides Derived from Bovine Lactoferricin and Buforin II: Antifungal Activity against Reference Strains and Clinical Isolates of spp.

Antimicrobial peptides (AMPs) are considered to be a valuable source for the identification and/or design of promising candidates for the development of antifungal treatments, since they have advantages such as lower tendency to induce resistance, ease of production, and high purity and safety. Bovine lactoferricin (LfcinB) and buforin II (BFII) are AMPs to which great antimicrobial potential has been attributed. The minimum motives with antimicrobial activity derived from LfcinB and BFII are RRWQWR and RLLR, respectively.

Synthetic Peptides in Doping Control: A Powerful Tool for an Analytical Challenge.

Peptides are very diverse molecules that can participate in a wide variety of biological processes. In this way, peptides are attractive for doping, since these molecules can activate or trigger biological processes that can improve the sports performance of athletes. Peptide molecules are found in the official World Anti-Doping Agency lists, mainly in sections S2, S4, and S5.

Omics in the detection and identification of biosynthetic pathways related to mycotoxin synthesis.

Mycotoxins are secondary metabolites that are known to be toxic to humans and animals. On the other hand, some mycotoxins and their analogues possess antioxidant as well as antitumor properties, which could be relevant in the fields of pharmaceutical analysis and food research. Omics techniques are a group of analytical tools applied in the biological sciences in order to study genes (genomics), mRNA (transcriptomics), proteins (proteomics), and metabolites (metabolomics).

Obtaining an immunoaffinity monolithic material: poly(GMA--EDMA) functionalized with an HPV-derived peptide using a thiol-maleimide reaction.

Metabolites have great potential for the design of biomarkers, since their presence or absence provides valuable information about a biological system. In this context, polyclonal antibodies are important metabolites for diagnostic procedures, but in some pathologies, it has been found that these metabolites are present at low concentrations, so it could be difficult to detect them. In this investigation, an organic monolithic material of poly(GMA--EDMA) was functionalized with a peptide Michael addition (thiol-maleimide) click chemistry.

Designing Chimeric Peptides: A Powerful Tool for Enhancing Antibacterial Activity.

Chimeric peptides containing short sequences derived from bovine Lactoferricin (LfcinB) and Buforin II (BFII) were synthetized using solid-phase peptide synthesis (SPPS) and characterized via reversed-phase liquid chromatography and mass spectrometry. The chimeras were obtained with high purity, demonstrating their synthetic viability. The chimeras' antibacterial activity against Gram-positive and Gram-negative strains was evaluated.

Short peptides conjugated to non-peptidic motifs exhibit antibacterial activity.

Short peptides derived from buforin and lactoferricin B were conjugated with other antimicrobial molecules of different chemical natures. The sequences RLLR, RLLRLLR, RWQWRWQWR, and RRWQWR were conjugated at their N-terminal end with non-peptidic molecules such as 6-aminohexanoic acid, ferrocene, caffeic acid, ferulic acid, and oxolinic acid. Peptide conjugates and unmodified peptides were synthesized by means of solid-phase peptide synthesis using the Fmoc/Bu strategy (SPPS-Fmoc/Bu), purified RP-SPE, and characterized RP-HPLC and MS.

Peptides Derived from (RRWQWRMKKLG)K- Induce Selective Cellular Death in Breast Cancer Cell Lines through Apoptotic Pathway.

The effect on the cytotoxicity against breast cancer cell lines of the substitution of Met residue in the sequence of the Bovine Lactoferricin-derived dimeric peptide LfcinB (20-30): (RRWQWRMKKLG)-K- with amino acids of different polarity was evaluated. The process of the synthesis of the LfcinB (20-30) analog peptides was similar to the original peptide. The cytotoxic assays showed that some analog peptides exhibited a significant cytotoxic effect against breast cancer cell lines HTB-132 and MCF-7, suggesting that the substitution of the Met with amino acids of a hydrophobic nature drastically enhances its cytotoxicity against HTB-132 and MCF-7 cells, reaching IC values up to 6 µM.

The tetrameric peptide LfcinB (20-25) derived from bovine lactoferricin induces apoptosis in the MCF-7 breast cancer cell line.

The cytotoxic effect of the tetrameric peptide LfcinB (20-25) against breast cancer cell line ATCC® HTB-22™ (MCF-7) was evaluated. The tetrameric peptide exhibited a concentration-dependent cytotoxic effect against MCF-7 cancer cells. The peptide at 22 µM had the maximum cytotoxic effect against MCF-7 cancer cells, reducing their cell viability to ∼20%.

Pullulan nanofibers containing the antimicrobial palindromic peptide LfcinB (21-25) obtained electrospinning.

Electrospinning technology is useful for making ultrafine drug-eluting fibers for the clinical treatment of wounds. We show the incorporation of an antimicrobial LfcinB-derived peptide into Pullulan nanofibers. The palindromic peptide LfcinB (21-25): RWQWRWQWR was synthesized, purified, and characterized by means of the RP-HPLC and MALDI-TOF MS methods.

Synthetic Peptide Purification via Solid-Phase Extraction with Gradient Elution: A Simple, Economical, Fast, and Efficient Methodology.

A methodology was implemented for purifying peptides in one chromatographic run via solid-phase extraction (SPE), reverse phase mode (RP), and gradient elution, obtaining high-purity products with good yields. Crude peptides were analyzed by reverse phase high performance liquid chromatography and a new mathematical model based on its retention time was developed in order to predict the percentage of organic modifier in which the peptide will elute in RP-SPE. This information was used for designing the elution program of each molecule.

Synergistic bactericide and antibiotic effects of dimeric, tetrameric, or palindromic peptides containing the RWQWR motif against Gram-positive and Gram-negative strains.

Dimeric and tetrameric peptides derived from LfcinB (20-25): RRWQWR, LfcinB (20-30): RRWQWRMKKLG, LfcinB (17-31): FKARRWQWRMKKLGA, or the palindromic sequence LfcinB (21-25): RWQWRWQWR were obtained by means of the SPPS-Fmoc/Bu methodology. The antibacterial activity of these molecules was evaluated against (ATCC 25922 and ATCC 11775), (ATCC 25923), (ATCC 29212), and (ATCC 27853). The dimer LfcinB (20-25): (RRWQWR)K-Ahx, the tetramer LfcinB (20-25): (RRWQWR)K-Ahx-C, and the palindromic sequence LfcinB (21-25) exhibited the highest antibacterial activity against the tested bacterial strains.

Design, Synthesis, and Use of Peptides Derived from Human Papillomavirus L1 Protein for the Modification of Gold Electrode Surfaces by Self-Assembled Monolayers.

In order to obtain gold electrode surfaces modified with Human Papillomavirus L1 protein (HPV L1)-derived peptides, two sequences, SPINNTKPHEAR and YIK, were chosen. Both have been recognized by means of sera from patients infected with HPV. The molecules, Fc-Ahx-SPINNTKPHEAR, Ac-C--(Fc)KSPINNTKPHEAR, Ac-C--SPINNTKPHEAR(Fc)K, C--SPINNTKPHEAR, and (YIK)₂--C, were designed, synthesized, and characterized.

Antibacterial Synthetic Peptides Derived from Bovine Lactoferricin Exhibit Cytotoxic Effect against MDA-MB-468 and MDA-MB-231 Breast Cancer Cell Lines.

Linear, dimeric, tetrameric, and cyclic peptides derived from lactoferricin B, containing the RRWQWR motif, were designed, synthesized, purified, and characterized using RP-HPLC chromatography and MALDI-TOF mass spectrometry. The antibacterial activity of the designed peptides against (ATCC 11775 and 25922) and their cytotoxic effect against MDA-MB-468 and MDA-MB-231 breast cancer cell lines were evaluated. Dimeric and tetrameric peptides showed higher antibacterial activity in both bacteria strains than linear peptides.

Antimicrobial Activity of Truncated and Polyvalent Peptides Derived from the FKCRRQWQWRMKKGLA Sequence against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923.

Peptides derived from LfcinB were designed and synthesized, and their antibacterial activity was tested against ATCC 25922 and ATCC 25923. Specifically, a peptide library was constructed by systemically removing the flanking residues (N or C-terminal) of Lfcin 17-31 (FKCRRWQWRMKKLGA), maintaining in all peptides the RRWQWR sequence that corresponds to the minimal antimicrobial motif. For this research, also included were (i) a peptide containing an Ala instead of Cys ([Ala]-LfcinB 17-31) and (ii) polyvalent peptides containing the RRWQWR sequence and a non-natural amino acid (aminocaproic acid).

Synthetic Peptides Derived from Bovine Lactoferricin Exhibit Antimicrobial Activity against E. coli ATCC 11775, S. maltophilia ATCC 13636 and S. enteritidis ATCC 13076.

Linear, dimeric, tetrameric, and cyclic peptides derived from lactoferricin B-containing non-natural amino acids and the RWQWR motif were synthesized, purified, and characterized using RP-HPLC, MALDI-TOF mass spectrometry, and circular dichroism. The antibacterial activity of peptides against ATCC 11775, ATCC 13636, and ATCC 13076 was evaluated. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined.