Toxicity Profiling of Biosurfactants Produced by Novel Marine Bacterial Strains

Surface active agents (SAAs), currently used in modern industry, are synthetic chemicals produced from non-renewable sources, with potential toxic impacts on humans and the environment. Thus, there is an increased interest for the identification and utilization of natural derived SAAs. As such, the marine environment is considered a promising source of biosurfactants with low toxicity, environmental compatibility, and biodegradation compared to their synthetic counterparts. MARISURF is a Horizon 2020 EU-funded project aiming to identify and functionally characterize SAAs, derived from a unique marine bacterial collection, towards commercial exploitation. Specifically, rhamnolipids produced by Marinobacter MCTG107b and Pseudomonas MCTG214(3b1) strains were previously identified and characterized while currently their toxicity profile was assessed by utilizing well-established methodologies. Our results showed a lack of cytotoxicity in in vitro models of human skin and liver as indicated by alamar blue and propidium iodide assays. Additionally, the use of the single gel electrophoresis assay, under oxidative stress conditions, revealed absence of any significant mutagenic/anti-mutagenic potential. Finally, both 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) cell-free assays, revealed no significant anti-oxidant capacity for neither of the tested compounds. Consequently, the absence of significant cytotoxicity and/or mutagenicity justifies their commercial exploitation and potential development into industrial end-user applications as natural and environmentally friendly biosurfactants.     

Screening methods for the proteolytic breakdown of gluten by lactic acid bacteria and enzyme preparations

 Gluten is the major protein in wheat and it is largely responsible for the rheological characteristics of bread dough. The sourdough process is a traditional dough fermentation process with lactic acid bacteria. The proteolytic activity of lactic acid bacteria derived from starter cultures used in sourdough or meat fermentation was tested on gluten as a substrate. The activities of commercial enzyme preparations, which were derived from bacterial or fungal sources, were also evaluated. Proteolytic breakdown of gluten protein in an agar medium by either bacterial culture or enzymes was evident by a clear zone around wells after staining with Coomassie blue. The increase in TCA-soluble material due to gluten breakdown was measured spectrophotometrically. A third test evaluated the release of free amino acids due to exoproteolytic activity. The agar based test showed positive results for the commercial enzyme preparations and one Micrococcus strain. All sourdough strains were positive in the enzyme test whereas some starters from the meat fermentation process were not able to break down gluten under test conditions. Variations in the release of free amino acid indicated differences in the enzyme systems of the lactic acid bacteria tested. Received: 25 February 1999     

The short-term effects of a hostility-reduction intervention on male coronary heart disease patients.

This preliminary study examined the effects of a hostility-reduction intervention on patients with coronary heart disease (CHD). Twenty-two high-hostile CHD men were matched on age and hostility and then randomly assigned to a hostility intervention (N?=?10) or an information-control group (N?=?12). Patients were reassessed immediately and 2 months posttreatment on hostility (with self-report and structured interview) and resting blood pressure. The intervention's overall effect size was moderately strong (d′?=?.62). Intervention patients reported at both reassessments and were observed at follow-up to be less hostile than controls. At follow-up, intervention patients had significantly lower diastolic blood pressure (DBP) than controls. Finally, reductions in hostility were significantly and positively correlated with reductions in DBP. Replication with a larger sample and CHD outcomes is recommended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electro-oxidation of rutin in the presence of <Emphasis Type="Italic">p</Emphasis>-toluenesulfinic acid

We report the electrochemical oxidation of rutin in acetonitrile-sodium phosphate (4:1 (v/v); pH 2.0) in the presence of p-toluenesulfinic acid. Cyclic voltammetry and controlled potential electrolysis were used to study rutin electro-oxidation and to prepare the sulfone derivatives. Chromatographic methods were employed to separate the products and IR, ¹H NMR, ¹³C NMR, MS and microanalysis to their characterization. Data from cyclic voltammetry allow the identification of three rutin oxidation processes in the presence of p-toluenesulfinic acid (E _p^I = 0.56 V, E _p^II = 0.81 V and E _p^III = 1.32 V). Only the electrode process around peak I was exhaustively studied. The first oxidation step leads to the formation of the corresponding o-quinone, which participates in a Michael addition reaction with the p-toluenesulfinic acid, forming the 6′(4-methylphenylsulfonyl)rutin and 6′(4-methylphenylsulfonyl)quercetin as majority products.     

Hydroxyapatites Produced by Wet-Chemical Methods

Hydroxyapatite samples were produced by two different wet-chemical methods, and characterized by X-ray diffraction, infrared (IR), thermal gravimetric analysis (TGA), scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectrometry, and compression strength measurements. The IR spectra showed the presence of CO₃²⁻ ions in all samples. After the sintering, the CO₃²⁻ bands almost disappeared, indicating a large release of CO₃²⁻ ions by the samples, which were also confirmed by TGA. By mixing samples produced by both methods, a bioceramic was prepared and, after sintering at 900°C for 1 h, compressive strengths of 26–30 MPa were obtained.     

Effect of king palm (Archontophoenix alexandrae) flour incorporation on physicochemical and textural characteristics of gluten-free cookies

The replacement of the blend of rice flour (70%) and corn starch (30%) with king palm flour [ Archontophoenix alexandrae (F. Muell.) H. Wendl. and Drude] at levels of 0–30% was investigated for its effects on the chemical and physical characteristics of gluten-free dough and cookies. Cookies containing 10, 20 and 30% of king palm flour were analysed by twenty-one celiac consumers through preference-ranking test. Ash, minerals, and dietary fibre contents increased in cookies that were added with king palm flour. Compared with the control dough, the incorporation of king palm flour increased the firmness and decreased the adhesiveness of dough samples. The incorporation of king palm flour increased the hardness of cookies in relation to the control dough. None of the cookies differed significantly ( P  > 0.05) in the lightness (L*) parameter. All formulations produced cookies with hue angles around 60, which indicate a tendency to brown colour. The study reveals that the incorporation of king palm flour showed desirable results in nutritional characteristics, because of the increase of the dietary fibre and minerals contents. In this study, the cookies preferred by celiac consumers were those containing 10 and 20% of king palm flour ( P  > 0.05).     

Mathematical modelling of moisture sorption isotherms and determination of isosteric heat of blueberry variety O'Neil

The sorption isotherms of blueberry variety O'Neil were determined at 20, 40 and 60 °C, for a range of water activity of 0.10–0.95. The isotherms showed that the equilibrium moisture content increased when temperature decreased at constant water activity. The BET, GAB, Halsey, Henderson, Caurie, Smith, Oswin and Iglesias-Chirife equations were tested for modelling the sorption isotherms. The results showed that GAB, BET and Halsey models gave the best fit quality for the experimental desorption data, and BET, Oswin and Henderson for adsorption data as suggested by the statistical tests employed. The net sorption heat was calculated using the Clausius–Clapeyron equation giving 38.62 kJ mol⁻¹ (desorption) and 30.88 kJ mol⁻¹ (adsorption) at a moisture content of 0.01 g water (g d.m.⁻¹). Tsami equation was applied to estimate the net isosteric heat of sorption as function of equilibrium moisture content with satisfactory results.     

Activated carbon supported Ni-Ca: Influence of reaction parameters on activity and stability of catalyst on methane reformation

The objective of the present work was to study the influence of some reaction parameters (temperature, chemical nature of pre-treatment gas, mass catalyst) on the yield of methane reforming with carbon dioxide on Ni (5%)-Ca (1%)/AC at atmospheric pressure. The obtained results show that the best system was pre-treated under He flow at 650 °C and then following the reaction at the same temperature. It was also detected that Ca plays a co-support role inhibiting the deactivation of catalyst at long periods of reaction. It can be concluded that it is possible to employ activated carbon as support for methane dry reformation obtaining representative methane conversions up to 40% at mild experimental conditions.     

Mixture design for evaluation of potassium sorbate and xanthan gum effect on properties of tapioca starch films obtained by extrusion

A mixture experimental design was used to study the physical and microbiological properties of tapioca starch–glycerol based edible films added with xanthan gum (XG) and potassium sorbate (PS) and obtained by extrusion technology. The results showed that PS presence decreased the ultimate tensile strength and elastic modulus and increased strain at break. XG produced a reinforcing effect on the films and also enhanced solubility in water and decreased moisture content. The analysis revealed significant interactions between components in the mixture. The water vapor permeability values ranged from 3.72 × 10^? 10 to 6.4 × 10^? 10 g/m s Pa. The PS concentration was not affected by the extrusion process and the preservative was available to act as an antimicrobial agent. Extruded films made from biopolymers showed a potential application in food technology as an active packaging.