Antiadhesive activity of the biosurfactant pseudofactin II secreted by the Arctic bacterium Pseudomonas fluorescens BD5

<p>Abstract</p> <p>Background</p> <p>Pseudofactin II is a recently identified biosurfactant secreted by <it>Pseudomonas fluorescens </it>BD5, the strain obtained from freshwater from the Arctic Archipelago of Svalbard. Pseudofactin II is a novel compound identified as cyclic lipopeptide with a palmitic acid connected to the terminal amino group of eighth amino acid in peptide moiety. The C-terminal carboxylic group of the last amino acid forms a lactone with the hydroxyl of Thr3.</p> <p>Adhesion is the first stage of biofilm formation and the best moment for the action of antiadhesive and anti-biofilm compounds. Adsorption of biosurfactants to a surface e.g. glass, polystyrene, silicone modifies its hydrophobicity, interfering with the microbial adhesion and desorption processes. In this study the role and applications of pseudofactin II as a antiadhesive compound has been investigated from medicinal and therapeutic perspectives.</p> <p>Results</p> <p>Pseudofactin II lowered the adhesion to three types of surfaces (glass, polystyrene and silicone) of bacterial strains of five species: <it>Escherichia coli, Enterococcus faecalis, Enterococcus hirae, Staphylococcus epidermidis, Proteus mirabilis </it>and two <it>Candida albicans </it>strains. Pretreatment of a polystyrene surface with 0.5 mg/ml pseudofactin II inhibited bacterial adhesion by 36-90% and that of <it>C. albicans </it>by 92-99%. The same concentration of pseudofactin II dislodged 26-70% of preexisting biofilms grown on previously untreated surfaces. Pseudofactin II also caused a marked inhibition of the initial adhesion of <it>E. faecalis, E. coli, E. hirae </it>and <it>C. albicans </it>strains to silicone urethral catheters. The highest concentration tested (0.5 mg/ml) caused a total growth inhibition of <it>S. epidermidis</it>, partial (18-37%) inhibition of other bacteria and 8-9% inhibition of <it>C. albicans </it>growth.</p> <p>Conclusion</p> <p>Pseudofactin II showed antiadhesive activity against several pathogenic microorganisms which are potential biofilm formers on catheters, implants and internal prostheses. Up to 99% prevention could be achieved by 0.5 mg/ml pseudofactin II. In addition, pseudofactin II dispersed preformed biofilms. Pseudofactin II can be used as a disinfectant or surface coating agent against microbial colonization of different surfaces, e.g. implants or urethral catheters.</p

Detection of inhibitors of Candida albicans Cdr transporters using a diS-C3(3) fluorescence

Candida albicans is a major cause of opportunistic and life-threatening, systemic fungal infections. Hence new antifungal agents, as well as new methods to treat fungal infections, are still needed. The application of inhibitors of drug-efflux pumps may increase the susceptibility of C. albicans to drugs. We developed a new fluorescence method that allows the in vivo activity evaluation of compounds inhibiting of C. albicans transporters. We show that the potentiometric dye 3,3′-dipropylthiacarbocyanine iodide diS-C3(3) is pumped out by both Cdr1 and Cdr2 transporters. The fluorescence labeling with diS-C3(3) enables a real-time observation of the activity of C. albicans Cdr1 and Cdr2 transporters. We demonstrate that enniatin A and beauvericin show different specificities toward these transporters. Enniatin A inhibits diS-C3(3) efflux by Cdr1 while beauvericin inhibits both Cdr1p and Cdr2p

Xylan decomposition in plant cell walls as an inducer of surfactin synthesis by Bacillus subtilis

Hemicellulose is the second most abundant plant heterogenous biopolymer. Among products obtained from a wide range of agro-residues, biosurfactants, e.g., surfactin (SU), are gaining increasing interest. Our previous studies have shown that a Bacillus subtilis strain can successfully produce a significant amount of SU using a rapeseed cake. This work aimed to investigate plant hemicellulose components as substrates promoting SU's efficient production by B. subtilis 87Y. Analyses of SU production, enzymatic activity and cell wall composition of hulled oat caryopses suggest that the main ingredients of plant hemicellulose, in particular xylan and its derivatives, may be responsible for an increased biosurfactant yield

Trehalose Lipid Biosurfactant Reduces Adhesion of Microbial Pathogens to Polystyrene and Silicone Surfaces: An Experimental and Computational Approach

Rhodococcus fascians BD8, isolated from Arctic soil, was found to produce biosurfactant when grown on n-hexadecane as the sole carbon source. The glycolipid product was identified as the trehalose lipid with a molecular mass of 848 g mol−1. The purified biosurfactant reduced the surface tension of water from 72 to 34 mN m−1. The critical micelle concentration of trehalose lipid was 0.140 mg mL−1. To examine its potential for biomedical applications, the antimicrobial and antiadhesive activity of the biosurfactant was evaluated against several pathogenic microorganisms. Trehalose lipid showed antimicrobial activity against resistant pathogens. The largest antimicrobial activities of trehalose lipid were observed against Vibrio harveyi and Proteus vulgaris. The highest concentration tested (0.5 mg mL−1) caused a partial (11–34%) inhibition of other Gram-positive and Gram-negative bacteria and 30% inhibition of Candida albicans growth. The trehalose lipid also showed significant antiadhesive properties against all of the tested microorganisms to polystyrene surface and silicone urethral catheters. The biosurfactant showed 95 and 70% antiadhesive activity against C. albicans and Escherichia coli, respectively. Finally, the role and application of trehalose lipid as an antiadhesive compound was investigated by the modification of the polystyrene and silicone surfaces. The intermolecular interaction energy calculations were performed for investigated complexes at the density functional level of theory. The results indicate that the presence of aromatic moieties can be substantial in the stabilization of trehalose lipid-surface complexes. The antimicrobial and antiadhesive activities of trehalose lipid make them promising alternatives to synthetic surfactants in a wide range of medical applications. Based on our findings, we propose that, because of its ability to inhibit microbial colonization of polystyrene and silicone surfaces, trehalose lipid can be used as a surface coating agent

Pierwsze doświadczenia z dwujamowymi stymulatorami firmy Medtronic objętymi alertem bezpieczeństwa

Introduction. Medtronic released a subset of dual chamber pacemakers that are suspected of a software error that can result in a lack of pacing. The Food and Drug Administration has deemed a class I recall. Material and methods. Medtronic advise reprogramming for patients with susceptible mode to non-susceptible pacing modes that are: DVI, DVIR, DOO(R), VVI, VVIR, VOO(R), VVT, AAI, AAIR, AOO(R), AAT, OVO. Results. 48 patients received an atrioventricular recalled device. Initially the DDD/DDDR mode was programmed in 44 patients and VVI/VVIR mode in the other four patients. The atrial and ventricular lead parameters such as pacing threshold, sensing threshold and impedance were within normal ranges. Pacemaker dependency in atria concerned 16/48 (33.33%) patients and in ventricles 13/48 (27.1%) patients. Three patients complained of fatigue, dizziness and near syncope. In 24 patients, devices were reprogrammed: in 17 (35.41%) patients to the DVIR mode and in seven (14.58%) patients to the VVI(R) mode. Two patients chose to be reprogrammed to the DDDR mode because of intolerance to non-susceptible pacing modes. Conclusions. Only three patients experienced symptoms that may be associated with pacemaker dysfunction; in 24/48 patients we programmed safety mode DVI(R) or VVI(R). The pacemaker dependency concerned almost 33.33% of patients.Wstęp. Firma Medtronic wypuściła na rynek grupę przedsionkowo-komorowych stymulatorów podejrzanych o błąd oprogramowania, który może prowadzić do wstrzymania stymulacji. Agencja ds. Żywności i Leków objęła powyższe urządzenia alertem klasy pierwszej. Materiały i metody. Firma Medtronic zaleca zmianę programu u chorych stymulowanych w trybie podatnym na wystąpienie błędu na tryb niepodatny, czyli: DVI, DVIR, DOO(R), VVI, VVIR, VOO(R), VVT, AAI, AAIR, AOO(R), AAT, OVO. Wyniki. Przedsionkowo-komorowy stymulator objęty obecnie alertem wszczepiono 48 chorym. U 44 pacjentów począt­kowo występował tryb DDD/DDDR, natomiast u 4 pacjentów — VVI/VVIR. Parametry elektrod, takie jak próg stymulacji, amplituda sygnału czy oporność, pozostawały w granicach normy. Zależność od stymulatora w przedsionkach dotyczyła 16 spośród 48 (33,33%) pacjentów, natomiast w komorach — 13 spośród 48 (27,1%) chorych. U 3 osób wystąpiły zmęczenie, zawroty głowy, prawie omdlenie. U 24 chorych stymulatory przeprogramowano w tryb bezpieczny — u 17 (35,41%) pacjentów w tryb DVIR, a 7 (14,58%) chorych w tryb VVI(R). Dwóch chorych zdecydowało o powrocie do trybu DDDR z powodu nietolerancji trybów niepodatnych na wystąpienie błędu. Wnioski. Trzech pacjentów doświadczyło objawów, które mogą się wiązać z dysfunkcją stymulatora, u 24 z 48 chorych zaprogramowano tryb bezpieczny [DVI(R) lub VVI(R)]. Stymulatorozależność dotyczyła 33,3% chorych

Azacarbazole n-3 and n-6 polyunsaturated fatty acids ethyl esters nanoemulsion with enhanced efficacy against Plasmodium falciparum

Alternative therapies are necessary for the treatment of malaria due to emerging drug resistance. However, many promising antimalarial compounds have poor water solubility and suffer from the lack of suitable delivery systems, which seriously limits their activity. To address this problem, we synthesized a series of azacarbazoles that were evaluated for antimalarial activity against D10 (chloroquine-sensitive) and W2 (chloroquine-resistant) strains of P. falciparum. The most active compound, 9H-3-azacarbazole (3), was encapsulated in a novel o/w nanoemulsion consisting of ethyl esters of polyunsaturated fatty acids n-3 and n-6 obtained from flax oil as the oil phase, Smix (Tween 80 and Transcutol HP) and water. This formulation was further analyzed using transmission electron microscopy, dynamic light scattering and in vitro and in vivo studies. It was shown that droplets of the 3-loaded nanosystem were spherical, with satisfactory stability, without cytotoxicity towards fibroblasts and intestinal cell lines at concentrations corresponding to twice the IC50 for P. falciparum. Moreover, the nanoemulsion with this type of oil phase was internalized by Caco-2 cells. Additionally, pharmacokinetics demonstrated rapid absorption of compound 3 (tmax = 5.0 min) after intragastric administration of 3-encapsulated nanoemulsion at a dose of 0.02 mg/kg in mice, with penetration of compound 3 to deep compartments. The 3-encapsulated nanoemulsion was found to be 2.8 and 4.2 times more effective in inhibiting the D10 and W2 strains of the parasite, respectively, compared to non-encapsulated 3. Our findings support a role for novel o/w nanoemulsions as delivery vehicles for antimalarial drugs

Capric Acid Secreted by S. boulardii Inhibits C. albicans Filamentous Growth, Adhesion and Biofilm Formation

Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and biofilm formation

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts. June 4-7, 2019, Szczyrk, Polan