Activity of Diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside, its Hydrochloride, and N,N-dialkyl Derivatives Against Non-albicans Candida Isolates.

Background: Candida albicans belongs to the most common fungal pathogens in humans, but recently an increased proliferation of strains called non-albicans Candida has been reported. Species belonging to this group are often characterised by a reduced susceptibility to antifungal agents.

Objective: In view of the emergence of non-albicans Candida and their resistance to available antifungals, an attempt has been made to develop novel effective agents.

In Vitro Evaluation of Cytotoxicity and Permeation Study on Lysine- and Arginine-Based Lipopeptides with Proven Antimicrobial Activity.

Owing to their excellent antimicrobial activities with a relatively low cost of production, lipopeptides are being intensively investigated as potential alternatives to popular antimicrobials. However, a critical obstacle for their application is a relatively high toxicity, hence a lot of attention has been paid to designing new molecules with optimal properties. In this study we synthesized the following lipopeptides: C-KK-NH₂, C-KεK-NH₂, C-KKK-NH₂, C-KRK-NH₂, C-RR-NH₂, C-RRR-NH₂, (C)₂-KKKK-NH₂ and (C)₂-KKKK-NH₂.

Influence of Amphibian Antimicrobial Peptides and Short Lipopeptides on Bacterial Biofilms Formed on Contact Lenses.

Unlabelled: The widespread use of contact lenses is associated with several complications, including ocular biofilm-related infections. They are very difficult to manage with standard antimicrobial therapies, because bacterial growth in a biofilm is associated with an increased antibiotic resistance. The principal aim of this study was to evaluate the efficacy of antimicrobial peptides (AMPs) in eradication of bacterial biofilms formed on commercially available contact lenses.

Cationic Net Charge and Counter Ion Type as Antimicrobial Activity Determinant Factors of Short Lipopeptides.

To get a better insight into the antimicrobial potency of short cationic lipopeptides, 35 new entities were synthesized using solid phase peptide strategy. All newly obtained lipopeptides were designed to be positively charged from +1 to +4. This was achieved by introducing basic amino acid - lysine - into the lipopeptide structure and had a hydrophobic fatty acid chain attached.

Human host defense peptides - role in maintaining human homeostasis and pathological processes.

The human body expresses over 100 host defense peptides and proteins (antimicrobial peptides, AMPs). The compounds are produced by tissues and mucosal surfaces, e.g.

Antimicrobial Peptides Under Clinical Trials.

Today microbial drug resistance has become a serious problem not only within inpatient setting but also within outpatient setting. Repeated intake and unnecessary usage of antibiotics as well as the transfer of resistance genes are the most important factors that make the microorganisms resistant to conventional antibiotics. A large number of antimicrobials successfully used for prophylaxis and therapeutic purposes have now become ineffective [1, 2].

The Antistaphylococcal Activity of Citropin 1.1 and Temporin A against Planktonic Cells and Biofilms Formed by Isolates from Patients with Atopic Dermatitis: An Assessment of Their Potential to Induce Microbial Resistance Compared to Conventional Antimicrobials.

Staphylococcus aureus (SA) colonizes the vast majority of patients with atopic dermatitis (AD). Its resistance to antibiotics and ability to form biofilms are the main origins of therapeutic complications. Endogenous antimicrobial peptides (AMPs) exhibit strong activity against SA, including antibiotic resistant strains as well as bacteria existing in biofilm form.

In Vitro Evaluation of the Allergic Potential of Antibacterial Peptides: Camel and Citropin.

Peptide-based drugs are promising group of compounds which are characterized by specificity to their in vivo targets and high potency of action (antineoplastic, immunoregulatory, antibacterial). The peptides, however, involve a relatively high risk of allergic reactions that are not predictable on the basis of their sequence and chemical properties. In this study, peripheral blood was obtained from 53 patients including 38 hypersensitive patients and 15 control patients.

N-Alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside; synthesis and antimicrobial activity.

Diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside is a synthetic saponin exhibiting attractive pharmacological properties. Different pathways tested by us to obtain this glycoside are summarized here. Moreover, the synthesis of N-alkyl and N,N-dialkyl derivatives of the glucopyranoside is presented.

Influence of Dimerization of Lipopeptide Laur-Orn-Orn-Cys-NH and an -terminal Peptide of Human Lactoferricin on Biological Activity.

Lactoferrin (LF) is a naturally occurring antimicrobial peptide that is cleaved by pepsin to lactoferricin (LFcin). LFcin has an enhanced antimicrobial activity as compared to that of LF. Recently several hetero- and homodimeric antimicrobial peptides stabilized by a single disulfide bond linking linear polypeptide chains have been discovered.

Identification and antifungal activity of novel organic compounds found in cuticular and internal lipids of medically important flies.

Novel organic compounds found in the cuticular and internal lipids of medically important flies were identified. Uracil, 9-tricosene, 1-oleoyl glycerol, dimethyl suberate and butyl stearate were tested for their potential antifungal activity. Minimal inhibitory concentrations of the compounds against reference strains of fungi were determined.

Self-assembly and interactions of short antimicrobial cationic lipopeptides with membrane lipids: ITC, FTIR and molecular dynamics studies.

In this work, the self-organization and the behavior of the surfactant-like peptides in the presence of biological membrane models were studied. The studies were focused on synthetic palmitic acid-containing lipopeptides, C16-KK-NH2 (I), C16-KGK-NH2 (II) and C16-KKKK-NH2 (III). The self-assembly was explored by molecular dynamics simulations using a coarse-grained force field.

Antimicrobial peptides as potential tool to fight bacterial biofilm.

Recently, the topic of biofilm has met a huge interest of researchers owing to a significant role played by this microbial life form in severe infections. These well organised three-dimensional microbial communities are characterized by a strong resistance to antimicrobials. Biofilms significantly contribute to morbidity and mortality as related infections are very difficult to treat due to their tendency to relapse after the withdrawal of antibiotics.

Biological and surface-active properties of double-chain cationic amino acid-based surfactants.

Cationic amino acid-based surfactants were synthesized via solid phase peptide synthesis and terminal acylation of their α and ε positions with saturated fatty acids. Five new lipopeptides, N-α-acyl-N-ε-acyl lysine analogues, were obtained. Minimum inhibitory concentration and minimum bactericidal (fungicidal) concentration were determined on reference strains of bacteria and fungi to evaluate the antimicrobial activity of the lipopeptides.

Synthetic amphibian peptides and short amino-acids derivatives against planktonic cells and mature biofilm of Providencia stuartii clinical strains.

Over the last decade, the growing number of multidrug resistant strains limits the use of many of the currently available chemotherapeutic agents. Furthermore, bacterial biofilm, due to its complex structure, constitutes an effective barrier to conventional antibiotics. The in vitro activities of naturally occurring peptide (Citropin 1.

Safety profile of antimicrobial peptides: camel, citropin, protegrin, temporin a and lipopeptide on HaCaT keratinocytes.

Antimicrobial peptides (AMPs) are an essential part of the innate immunity of the skin and mucosal surfaces. They have a broad spectrum of antimicrobial activity: antibacterial, antifungal, antiviral as well as antiprotozoal. Numerous studies using AMPs as potential agents against different microbes has been performed during the last two decades.

The antifungal activity of fatty acids of all stages of Sarcophaga carnaria L. (Diptera: Sarcophagidae).

Fatty acids as components of cuticular lipids of insects play a significant role in antifungal in protection against fungal infection. The chemical composition of cuticular and internal extracts obtained from all developmental stages of flesh flies Sarcophaga carnaria was identified. The fatty acids were detected using gas chromatography coupled with mass spectrometry and the most abundant for all examined stages were: 18:1 > 16:0 > 16:1 > 18:0 > 18:2.

The antifungal activity of the cuticular and internal fatty acid methyl esters and alcohols in Calliphora vomitoria.

SUMMARY The composition of the fatty acid methyl ester (FAME) and alcohol fractions of the cuticular and internal lipids of Calliphora vomitoria larvae, pupae and male/female adults was obtained by separating these two fractions by HPLC-LLSD and analysing them quantitatively using GC-MS. Analysis of the cuticular lipids of the worldwide, medically important ectoparasite C. vomitoria revealed 6 FAMEs with odd-numbered carbon chains from C15:0 to C19:0 in the larvae, while internal lipids contained 9 FAMEs ranging from C15:1 to C19:0.

Free fatty acids in the cuticular and internal lipids of Calliphora vomitoria and their antimicrobial activity.

The cuticular and internal lipid composition in Calliphora vomitoria larvae, pupae, and male and female adults was studied. The free fatty acid (FA) compositions of the lipids were chemically characterized using gas chromatography (GC) and gas chromatography-electron impact mass spectrometry (GC-MS). Analyses of cuticular extracts from larvae, pupae, and male and female adults revealed that the carbon numbers of the acids ranged from C7:0 to C22:0, from C8:0 to C24:0, from C7:0 to C24:0 and from C7:0 to C22:0 respectively.

Activity of short lipopeptides and conventional antimicrobials against planktonic cells and biofilms formed by clinical strains of Staphylococcus aureus.

Background: The therapy for staphylococcal skin diseases is facing several difficulties caused by the growth of biofilms and development of resistant strains. Short synthetic lipopeptides designed on the basis of antimicrobial peptide structure seem to provide an alternative to conventional therapy. The purpose of this study was to synthesize a group of lipopeptides and evaluate their antistaphylococcal activity against biofilms formed by clinical strains of Staphylococcus aureus.

Synthesis, biological activity and conformational analysis of head-to-tail cyclic analogues of LL37 and histatin 5.

LL37 and histatin 5 are antimicrobial peptides. LL37 exhibits killing activity against a broad spectrum of pathogens, whereas histatin 5 is primarily an antifungal agent. Head-to-tail cyclization of histatin 5 did not affect its antimicrobial and haemolytic activity.

Composition and antimicrobial activity of fatty acids detected in the hygroscopic secretion collected from the secretory setae of larvae of the biting midge Forcipomyia nigra (Diptera: Ceratopogonidae).

The hygroscopic secretion produced by the secretory setae of terrestrial larvae of the biting midge Forcipomyia nigra (Winnertz) was analysed using gas chromatography coupled with mass spectrometry (GC-MS). The viscous secretion is stored at the top of each seta and absorbs water from moist air. GC-MS analyses (four independent tests) showed that the secretion contained 12 free fatty acids, the most abundant of which were oleic (18:1), palmitic (16:0), palmitoleic (16:1) and linoleic (18:2).

Antimicrobial activity of alcohols from Musca domestica.

Information on the stimulatory and inhibitory effects of cuticular alcohols on growth and virulence of insecticidal fungi is unavailable. Therefore, we set out to describe the content of cuticular and internal alcohols in the body of housefly larvae, pupae, males and females. The total cuticular alcohols in larvae, males and females of Musca domestica were detected in comparable amounts (4.

Activity of Antimicrobial Peptides and Conventional Antibiotics against Superantigen Positive Staphylococcus aureus Isolated from the Patients with Neoplastic and Inflammatory Erythrodermia.

Superantigens are proteins comprising a group of molecules produced by various microorganisms. They are involved in pathogenesis of several human diseases. The aim of the study was the comparison of susceptibility to antibiotics and antimicrobial peptides (AMPs) of Staphylococcus aureus (SA) strains producing staphylococcal enterotoxins SEA, SEB, SEC, SED, and TSST-1 and nonproducing ones.