Production and characterization of lipopeptide biosurfactant from a new strain of Pseudomonas antarctica 28E using crude glycerol as a carbon source.

Pseudomonas is a cosmopolitan genus of bacteria found in soil, water, organic matter, plants and animals and known for the production of glycolipid and lipopeptide biosurfactants. In this study bacteria (laboratory collection number 28E) isolated from soil collected in Spitsbergen were used for biosurfactant production. 16S rRNA sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) revealed that this isolate belongs to the species Pseudomonas antarctica. In the present study, crude glycerol, a raw material obtained from several industrial processes, was evaluated as a potential low-cost carbon source to reduce the costs of lipopeptide production. Among several tested glycerols, a waste product of stearin production, rich in nitrogen, iron and calcium, ensured optimal conditions for bacterial growth. Biosurfactant production was evidenced by a reduction of surface tension (ST) and an increase in the emulsification index (E24%). According to Fourier-transform infrared spectroscopy (FTIR) and electrospray ionization mass spectrometry (ESI-MS), the biosurfactant was identified as viscosin. The critical micelle concentration (CMC) of lipopeptide was determined to be 20 mg L-1. Interestingly, viscosin production has been reported previously for Pseudomonas viscosa, Pseudomonas fluorescens and Pseudomonas libanensis. To the best of our knowledge, this is the first report on viscosin production by a P. antarctica 28E. The results indicated the potential of crude glycerol as a low-cost substrate to produce a lipopeptide biosurfactant with promising tensioactive and emulsifying properties.

Screening of Fenofibrate-Simvastatin Solid Dispersions in the Development of Fixed-Dose Formulations for the Treatment of Lipid Disorders.

The combination of statins and fibrates in the treatment of lipid abnormalities effectively regulates individual lipid fraction levels. In this study, the screening and assessment of the physicochemical properties of simvastatin-fenofibrate solid dispersions were performed. Fenofibrate and simvastatin were processed using the kneading method in different weight ratios, and the resulting solid dispersions were assessed using differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), contact angle, as well as dissolution tests. The obtained results confirmed the formation of a simple eutectic phase diagram, with a eutectic point containing 79 wt% fenofibrate and 21 wt% simvastatin, lack of chemical interactions between the ingredients, and simvastatin impact on improving fenofibrate dissolution profile, due to the formation of crystalline solid dispersions by the kneading method.

All-Cause Mortality and Trimethylamine N-Oxide Levels in Patients with Cardiovascular Disease.

INTRODUCTION: Trimethylamine N-oxide (TMAO) is an organic compound with a well-established involvement in the pathogenesis of cardiovascular disease (CVD). However, data on the links between TMAO levels and cardiovascular mortality in Polish patients are lacking. OBJECTIVES: We aimed to assess the relationship between serum TMAO levels and 5-year mortality in Polish patients with CVD. PATIENTS AND METHODS: We retrospectively assessed serum TMAO levels in 1,036 consecutive patients (median age, 62 years; men, 61%) hospitalized between 2013 and 2015. Correlations between TMAO levels and 5-year mortality as well as anthropometric and biochemical parameters were assessed for the whole population and the subgroups of patients with acute coronary syndrome, stable coronary syndrome (SCS), chronic heart failure (HF), and atrial fibrillation (AF). RESULTS: In the univariate analysis, increased TMAO levels predicted 5-year mortality without clinically significant power (hazard ratio [HR], 1.01; 95% CI: 1.006-1.018; p < 0.0001). However, even this weak effect was lost in the multivariate analysis after adjustment for age, sex, comorbidities, and laboratory parameters. In the whole study group, TMAO levels in the fourth quartile of concentration (>6.01 µM) predicted 5-year mortality only in the univariate analysis (HR: 1.55; 95% CI: 1.34-1.79; p < 0.0001). In subgroup univariate analysis, TMAO levels predicted 5-year mortality in patients with SCS, chronic HF, and AF. CONCLUSIONS: Despite the promising results of previous studies, our study shows that the level of TMAO has at most moderate value in predicting all-cause mortality. TMAO levels depend on other clinical variables, which limits the use of TMAO as an independent predictor of mortality in these patients.

Citrulline and long-term mortality in patients with cardiovascular disease.

BACKGROUND: Cardiovascular disease (CVD) is associated with intestinal barrier dysfunction and increased intestinal permeability. Increased intestinal permeability to gut microbial metabolites may accelerate the progression of CVD. Plasma citrulline levels are a marker of functional enterocyte mass, and reduced citrulline levels indicate intestinal epithelial damage. Citrulline was reported as a useful prognostic marker in critically ill patients. However, data are lacking on the association of citrulline with long-term mortality in patients with CVD and with the levels of trimethylamine N-oxide (TMAO), a microbiota-derived metabolite which has been implicated in the pathogenesis of CVD. OBJECTIVES: To assess the effect of citrulline levels, a marker of intestinal barrier disruption, on long-term mortality in patients with CVD. Moreover, the relationship between the concentrations of 2 biomarkers - citrulline and TMAO - was assessed. MATERIAL AND METHODS: Serum citrulline levels were retrospectively assessed in 1036 consecutive patients with CVD (median age: 62 years; 61% men) hospitalized between 2013 and 2015. Associations of citrulline levels with 5-year mortality rates as well as anthropometric and biochemical parameters were evaluated for the entire study group and in subgroups of patients with acute coronary syndrome (ACS), chronic coronary syndrome, chronic heart failure (chronic HF), and atrial fibrillation (AF). Correlations between serum citrulline and TMAO levels were assessed. RESULTS: The median citrulline level in the study population was 22.5 µM (interquartile range (IQR): 17.8-27.9). Citrulline levels were not associated with 5-year mortality in patients with CVD (hazard ratio (HR) = 0.99; 95% confidence interval (95% CI): 0.97-1.00; p = 0.49). Median citrulline levels differed significantly between deceased patients and survivors at 5 years in patients with ACS (p = 0.025). There were no significant correlations between citrulline and TMAO levels (Kendall's tau = 0.027). CONCLUSIONS: Decreasing citrulline levels do not predict long-term mortality of hospitalized patients with CVD. Moreover, they are not associated with the serum levels of TMAO in these patients.

Mechanisms of curcumin-based photodynamic therapy and its effects in combination with electroporation: An in vitro and molecular dynamics study.

Photodynamic therapy (PDT) and electrochemotherapy (ECT) are two methods designed to enhance the anticancer potential of various drugs. Various clinical trials proved the efficacy of both ECT and PDT in melanoma treatment. Curcumin is a natural polyphenolic compound with high anticancer potential against melanoma due to its light absorption properties and toxicity towards cancer cells; however, high reactivity and amphipathic structure of curcumin are limiting its utility. This study aimed to propose the most effective protocol for antimelanoma combination of both therapies (PDT and ECT) in the context of curcumin. The in vitro studies were carried on melanotic melanoma (A375), amelanotic melanoma (C32) and fibroblast (HGF) cell lines. In molecular dynamics studies curcumin presented the single-layer localization in the water-membrane interphase. Further, the mass spectrometry studies exposed that during the PDT treatment curcumin is degraded to vanillin, feruloylmethane, and ferulic acid. Instant ECT with curcumin followed by PDT is the most efficient approach due to its selective genotoxicity towards malignant cells. The metabolic activity of fibroblasts decreased, however, at the same time the fragmentation of DNA did not occur. Additionally, instant PDT with curcumin followed by ECT after 3 h of incubation was a therapy selective towards melanotic melanoma.

The Potential Antimicrobial Action of Human Mucin 7 15-Mer Peptide and Its Metal Complexes.

Mucin 7 (encoded byMUC7) is a human salivary protein that has a role in the natural immune system. Fragments of mucin 7 exhibit antimicrobial activity against bacteria and yeast. Although the antimicrobial properties of peptides have been known and studied for decades, the exact mechanism of action of antimicrobial peptides (AMPs) is still unclear. It is known that some AMPs require divalent metal ions to activate their activity. Herein, we investigated three 15-mer MUC7 peptides, one of which (mother peptide, sequence, L3) is a synthetic analog of a fragment naturally excised from MUC7 (with His3, His8, and His 14) and its two structural analogs, containing only two histidine residues, His3, His13 and His8, His13 (L2 and L1, respectively). Since there is a correlation between lipophilicity, the presence of metal ions (such as Cu(II) and Zn(II)) and antimicrobial activity of AMP, antimicrobial properties of the studied peptides, as well as their complexes with Cu(II) and Zn(II) ions, were tested for activity against Gram-positive (Enterococcus faecalis, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria and fungi (Candida albicans). The results were correlated with their lipophilicity. Coordination and thermodynamic studies (potentiometry, UV-Vis, CD) revealed the formation of mainly mononuclear complexes in solution for all studied systems with different stability in the physiological pH range.

Human salivary MUC7 mucin fragment and its analogues. Coordination and biological studies.

Mucin 7 (called MUC7 or MG2) is a salivary protein whose fragments exhibit a strong antimicrobial activity and is a natural protection of organisms against pathogens. Up to date however the exact mechanism of their actions is unknown. One hypothesis covers an involvement of biologically occurring metal ions in this process. Herein, three 12-mer peptides have been included in the study, one of which (mother-peptide sequence, L3) is a direct analogue of a fragment naturally cut out from the MUC7 (with His3 and His8) and its two structural analogues, containing only one histidine residues His3 or His8 (L2 and L1, respectively), which are essential for binding to metal ions. Antimicrobial properties of the studied peptides as well as their complexes have been tested against bacterial and fungal strains revealing activity towards Gramm-positive bacteria (Enterococcus faecalis and Staphylococcus epidermidis) which were slightly enhanced upon Cu(II) or Zn(II) ions coordination. The study of both the biological and thermodynamic properties of considered systems has not been measured before. Exact coordination studies (potentiometry, ultraviolet/visible spectroscopy - UV-Vis, circular dichroism spectroscopy - CD) revealed the formation of mainly mono-nuclear complexes in solution for all studied systems in which the binding abilities turned out to be inversely proportional to the antimicrobial properties exhibited. However, distinctly different lipophilicity of peptides, the reduction of which (also upon metal coordination) increases the ability to inhibit the growth of E. faecalis and S. epidermidis strains, seems to be the most important factor of their activity.

Parameters of Oxidative and Inflammatory Status in a Three-Month Observation of Patients with Acute Myocardial Infarction Undergoing Coronary Angioplasty-A Preliminary Study.

Background and Objectives: Patients with acute myocardial infarction (MI) are usually treated with percutaneous transluminal coronary angioplasty (PTCA), which is burdened with a risk of postoperative complications, often accompanied by biochemical disturbances. The aim of our study was to evaluate a set of selected parameters of oxidative and inflammatory status, which could be useful in the management of post-procedural care in MI patients after PTCA. Materials and Methods: In this preliminary study, ischemia modified albumin (IMA), advanced oxidation protein products (AOPP), thiol groups (SH), total antioxidant status (TAS), insulin growth factor-1 (IGF-1), presepsin (PSP), and trimethylamine N-oxide (TMAO) were chosen as candidate biomarkers, and were determined in patients with MI who underwent PTCA at two time points: During cardiac episodes (at admission to the hospital, T0) and 3 months later (T3). Results: Most of the examined parameters were significantly different between patients and control subjects (except for IMA and TAS), but only hsCRP changed significantly during the time of observation (T0 vs. T3). Discriminant analysis created a model composed of AOPP, hsCRP, PSP, and TMAO, which differentiated male subjects into a group with MI and a control (without cardiovascular diseases). Conclusion: This set of parameters seems useful in evaluating inflammatory and oxidative status in MI patients after PTCA.

Pneumococcal histidine triads - involved not only in Zn2+, but also Ni2+ binding?

Polyhistidine triad proteins, which participate in Zn2+ uptake in Streptococcus pneumoniae, contain multiple copies of the HxxHxH (histidine triad motif) sequence. We focus on three such motifs from one of the most common and well-conserved polyhistidine triad proteins, PhtA, in order to understand their bioinorganic chemistry; particular focus is given to (i) understanding which of the PhtA triads binds Zn2+ with the highest affinity (and why) and (ii) explaining whether Ni2+ (also crucial for bacterial survival and virulence) could potentially outcompete Zn2+ at its native binding site. There is no significant difference in the stability of zinc(ii) complexes with the three studied protein fragments, but one of the nickel(ii)-polyhistidine triads is remarkably stable; we explain why and hypothesize about the biological importance of this finding.

The Properties and Activity of TiO2 /beta-SiC Nanocomposites in Organic Dyes Photodegradation.

The TiO2 /beta-SiC nanocomposites containing 0-25 wt. % of beta-SiC were synthesized by the sol-gel method and tested in the photodegradation of methylene blue and methyl orange water solutions. With the increase in SiC content, only a slight decrease in energy band gap was observed (3.19-3.12 eV), together with significant increase in the surface area of the catalysts (42.7-80.4 m2 g-1 ). In the synthesized material, the anatase phase of TiO2 was present in the form of small agglomerates resulting from the mechanical mixing process. In the process conditions (catalyst concentration 0.5 g L-1 , initial dye concentration 100 ppm, light source 100 W UV-Vis lamp), we have observed no signs of catalyst deactivation. The significantly higher photodegradation activity of methylene blue than methyl orange can be attributed to the preferable pH of the solution compared to pHPZC and the cationic character of the first dye. In case of methyl orange, pH process conditions substantially limit the contact of the catalyst with the dye, as negatively charged surface of the catalysts repels the dissociated anionic dye molecules.

Analysis of Antioxidant Polyphenols in Loquat Leaves using HPLC-based Activity Profiling.

Leaves of Eriobotryajaponica (loquat) have been used in Traditional Chinese Medicine with beneficial effects in numerous diseases. Extracts from loquat leaves are rich in antioxidants, containing among others: triterpenes, sesquiterpenes, flavonoids, tannins, and megastigmane glycosides. However, there is no conclusive study revealing which of these compounds are the main bioactive principles. The goal of this study was to pinpoint compounds responsible for strong antioxidant activity. Eriobotryaefolium was extracted and fractionated between solvents of increasing polarity. All extracts and fractions were screened for total polyphenols and tannins, and antioxidant activity was checked by DPPH, phosphomolybdenum and linoleic acid tests. The ethyl acetate fraction demonstrated the highest antioxidant activity and contained the largest amount of polyphenols. Applying HPLC-based activity profiling to localize antioxidants revealed that cinchonain IIb, as well as flavonoid glycosides such as hyperoside, isoquercitrin, kaempferol glycosides, quercetin-rhamnoside, as well as two tentatively identified protocatechuic acid derivatives are the main substances responsible for the strong antioxidant activity of the ethyl acetate fraction.

The interaction of the ubiquitin 50-59 fragment with copper(II) ions.

In the present study, the coordination abilities of ubiquitin 50-59 fragment and its analog containing ßAsp residue are discussed. The analysis is provided based on the results of potentiometric and spectroscopic measurements supported by quantum-chemical calculations. Interesting differences in the coordination of the metal cation by modified and unmodified peptides are reported. Moreover, in order to further characterize experimentally observed species, we performed quantum-chemical calculations for structures mimicking ubiquitin 50-59 fragment as a step toward a better understanding of structural and energetical aspects related to the coordination abilities of ubiquitin.