Antibacterial Use of Macroalgae Compounds against Foodborne Pathogens.

The search for food resources is a constant in human history. Nowadays, the search for natural and safe food supplies is of foremost importance. Accordingly, there is a renewed interest in eco-friendly and natural products for substitution of synthetic additives. In addition, microbial contamination of food products during their obtaining and distribution processes is still a sanitary issue, and an important target for the food industry is to avoid food contamination and its related foodborne illnesses. These diseases are fundamentally caused by certain microorganisms listed in this review and classified according to their Gram negative or positive character. Algae have proven to possess high nutritional value and a wide variety of biological properties due to their content in active compounds. Among these capabilities, macroalgae are recognized for having antimicrobial properties. Thus, the present paper revises the actual knowledge of microbial contaminants in the food industry and proposes antimicrobial algal compounds against those pathogenic bacteria responsible for food contamination as valuable molecules for its growth inhibition. The capacity of algae extracts to inhibit some major food pathogen growth was assessed. Moreover, the main applications of these compounds in the food industry were discussed while considering their favorable effects in terms of food safety and quality control.

Quality improvement of common carp (Cyprinus carpio L.) meat fortified with n-3 PUFA.

The effect of carp feeding with n-3 PUFA-enriched feed (Schizochytrium sp. meal or salmon oil) on nutritional quality indicators (proximal composition, fatty acid profile of fat) and culinary quality (color parameters, texture, sensory properties) was evaluated. Highly significant effects of carp nutrition on chemical composition and fat characteristics, L* and a* color parameters, muscle fiber size, endomysium thickness, moisture and taste of fillets were determined. Fillets obtained from carps fed with the experimental feed contained less protein and more crude fat and had larger muscle fibers, but scored more highly in the sensory evaluation of moisture and fishy taste. In the fat of carp fed the enriched feed, a greater share of total PUFA, n-3 PUFA, total EPA and DHA, n-3/n-6 ratio, and a smaller share of total MUFA were observed compared with control fish. However, no effect of nutrition on the texture of carp fillets, assessed either instrumentally or using sensory methods, was found. The use of Schizochytrium sp. meal as a source of EPA and DHA gave much better results than salmon oil, as it allowed a higher content of these valuable fatty acids to be achieved, without compromising quality.

The Fatty Acid Profile in Patients with Newly Diagnosed Diabetes: Why It Could Be Unsuspected.

CONTEXT: Several studies have shown a link between proinflammatory activity and the presence or deficit of some fatty acids. Inflammation is associated with several diseases including diabetes. OBJECTIVE: To characterize and compare the fatty acids profiles in children with inaugural type 1 diabetes, diabetic children (at least 1 year after diagnosis), and healthy children. DESIGN: Plasma fatty acids profiles in children with inaugural diabetes, children with noninaugural diabetes, and controls, all of whom were prepubescent with a BMI < 85th percentile, were evaluated. RESULTS: Omega-3 fatty acid levels were higher in recently diagnosed subjects with diabetes than in controls. The ratio of omega-6/omega-3 fatty acids was higher in the control population. Omega-6 fatty acid levels were higher in the nonrecent diabetic subjects than in the children with recently diagnosed diabetes, and the levels were higher in the nonrecent diabetes group compared to the control group. CONCLUSION: Our findings showed higher levels of alpha-linolenic acid, EPA, and DHA, as well as mono- and polyunsaturated fatty acids, in diabetic children. These findings reinforce the importance of precocious nutritional attention and intervention in the treatment of diabetic children.

Biological and physicochemical properties of biosurfactants produced by Lactobacillus jensenii P6A and Lactobacillus gasseri P65.

BACKGROUND: Lactobacillus species produce biosurfactants that can contribute to the bacteria's ability to prevent microbial infections associated with urogenital and gastrointestinal tracts and the skin. Here, we described the biological and physicochemical properties of biosurfactants produced by Lactobacillus jensenii P6A and Lactobacillus gasseri P65. RESULTS: The biosurfactants produced by L. jensenii P6A and L. gasseri P65 reduced the water surface tension from 72 to 43.2 mN m-1 and 42.5 mN m-1 as their concentration increased up to the critical micelle concentration (CMC) values of 7.1 and 8.58 mg mL-1, respectively. Maximum emulsifying activity was obtained at concentrations of 1 and 5 mg mL-1 for the P6A and P65 strains, respectively. The Fourier transform infrared spectroscopy data revealed that the biomolecules consist of a mixture of carbohydrates, lipids and proteins. The gas chromatography-mass spectrum analysis of L. jensenii P6A biosurfactant showed a major peak for 14-methypentadecanoic acid, which was the main fatty acid present in the biomolecule; conversely, eicosanoic acid dominated the biosurfactant produced by L. gasseri P65. Although both biosurfactants contain different percentages of the sugars galactose, glucose and ribose; rhamnose was only detected in the biomolecule produced by L. jensenii P6A. Emulsifying activities were stable after a 60-min incubation at 100 °C, at pH 2-10, and after the addition of potassium chloride and sodium bicarbonate, but not in the presence of sodium chloride. The biomolecules showed antimicrobial activity against clinical isolates of Escherichia coli and Candida albicans, with MIC values of 16 µg mL-1, and against Staphylococcus saprophyticus, Enterobacter aerogenes and Klebsiella pneumoniae at 128 µg mL-1. The biosurfactants also disrupted preformed biofilms of microorganisms at varying concentrations, being more efficient against E. aerogenes (64%) (P6A biosurfactant), and E. coli (46.4%) and S. saprophyticus (39%) (P65 biosurfactant). Both strains of lactobacilli could also co-aggregate pathogens. CONCLUSIONS: This report presents the first characterization of biosurfactants produced by L. jensenii P6A and L. gasseri P65. The antimicrobial properties and stability of these biomolecules indicate their potential use as alternative antimicrobial agents in the medical field for applications against pathogens that are responsible for infections in the gastrointestinal and urogenital tracts and the skin.

DAX1 Overexpression in Pediatric Adrenocortical Tumors: A Synergic Role with SF1 in Tumorigenesis.

DAX1 transcription factor is a key determinant of adrenogonadal development, acting as a repressor of SF1 targets in steroidogenesis. It was recently demonstrated that DAX1 regulates pluripotency and differentiation in murine embryonic stem cells. In this study, we investigated DAX1 expression in adrenocortical tumors (ACTs) and correlated it with SF1 expression and clinical parameters. DAX1 and SF1 protein expression were assessed in 104 ACTs from 34 children (25 clinically benign and 9 malignant) and 70 adults (40 adenomas and 30 carcinomas). DAX1 gene expression was studied in 49 ACTs by quantitative real-time PCR. A strong DAX1 protein expression was demonstrated in 74% (25 out of 34) and 24% (17 out of 70) of pediatric and adult ACTs, respectively (χ(2)=10.1, p=0.002). In the pediatric group, ACTs with a strong DAX1 expression were diagnosed at earlier ages than ACTs with weak expression [median 1.2 (range, 0.5-4.5) vs. 2.2 (0.9-9.4), p=0.038]. DAX1 expression was not associated with functional status in ACTs. Interestingly, a positive correlation was observed between DAX1 and SF1 protein expression in both pediatric and adult ACTs (r=0.55 for each group separately; p<0.0001). In addition, DAX1 gene expression was significantly correlated with SF1 gene expression (p<0.0001, r=0.54). In conclusion, DAX1 strong protein expression was more frequent in pediatric than in adult ACTs. Additionally, DAX1 and SF1 expression positively correlated in ACTs, suggesting that these transcription factors might cooperate in adrenocortical tumorigenesis.

Analysing organochlorine pesticides in strawberry jams using GC-ECD, GC-MS/MS and QuEChERS sample preparation.

This paper describes a comparison of adaptations of the QuEChERS (quick, easy, cheap, effective, rugged and safe) approach for the determination of 14 organochlorine pesticide (OCP) residues in strawberry jam by concurrent use of gas chromatography (GC) coupled to electron capture detector (ECD) and GC tandem mass spectrometry (GC-MS/MS). Three versions were tested based on the original QuEChERS method. The results were good (overall average of 89% recoveries with 15% RSD) using the ultrasonic bath at five spiked levels. Performance characteristics, such as accuracy, precision, linear range, limits of detection (LOD) and quantification (LOQ), were determined for each pesticide. LOD ranged from 0.8 to 8.9 µg kg(-1); LOQ was in the range of 2.5-29.8 µg kg(-1); and calibration curves were linear (r(2)>0.9970) in the whole range of the explored concentrations (5-100 µg kg(-1)). The LODs of these pesticides were much lower than the maximum residue levels (MRLs) allowed in Europe for strawberries. The method was successfully applied to the quantification of OCP in commercially available jams. The OCPs were detected lower than the LOD.

Groundwater from infiltration galleries used for small public water supply systems: contamination with pesticides and endocrine disruptors.

Infiltration galleries are among the oldest known means used for small public water fountains. Owing to its ancestral origin they are usually associated with high quality water. Thirty-one compounds, including pesticides and estrogens from different chemical families, were analysed in waters from infiltration galleries collected in Alto Douro Demarcated Wine region (North of Portugal). A total of twelve compounds were detected in the water samples. Nine of these compounds are described as presenting evidence or potential evidence of interfering with the hormone system of humans and wildlife. Although concentrations of the target analytes were relatively low, many of them below their limit of quantification, four compounds were above quantification limit and two of them even above the legal limit of 0.1 µg/L: dimethoate (30.38 ng/L), folpet (64.35 ng/L), terbuthylazine-desethyl (22.28 to 292.36 ng/L) and terbuthylazine (22.49 to 369.33 ng/L).

Quantification of endocrine disruptors and pesticides in water by gas chromatography-tandem mass spectrometry. Method validation using weighted linear regression schemes.

A multi-residue methodology based on a solid phase extraction followed by gas chromatography-tandem mass spectrometry was developed for trace analysis of 32 compounds in water matrices, including estrogens and several pesticides from different chemical families, some of them with endocrine disrupting properties. Matrix standard calibration solutions were prepared by adding known amounts of the analytes to a residue-free sample to compensate matrix-induced chromatographic response enhancement observed for certain pesticides. Validation was done mainly according to the International Conference on Harmonisation recommendations, as well as some European and American validation guidelines with specifications for pesticides analysis and/or GC-MS methodology. As the assumption of homoscedasticity was not met for analytical data, weighted least squares linear regression procedure was applied as a simple and effective way to counteract the greater influence of the greater concentrations on the fitted regression line, improving accuracy at the lower end of the calibration curve. The method was considered validated for 31 compounds after consistent evaluation of the key analytical parameters: specificity, linearity, limit of detection and quantification, range, precision, accuracy, extraction efficiency, stability and robustness.

Identification and characterization of bioemulsifier-producing yeasts isolated from effluents of a dairy industry.

New bioemulsifier-producing yeasts were isolated from the biological wastewater treatment plant of a dairy industry. Of the 31 bioemulsifier-producing strains, 12 showed emulsifying activity after 2months of incubation, with E(24) values ranging from 7% to 78%. However, only Trichosporon loubieri CLV20, Geotrichum sp. CLOA40, and T. montevideense CLOA70 exhibited high emulsion-stabilizing capacity, with E(24) values of 78%, 67%, and 66%, respectively. These isolates were shown to induce a strong emulsion stabilizing activity rather than the reduction of the interfacial tension. These strains exhibited similar growth rates in the exponential growth phase, with a clear acceleration after 24h and stabilization of the activity after 144h. Emulsification and stability properties of the bioemulsifiers were compared to those of commercial surfactants after the addition of NaCl and exposure to temperature of 100 degrees C. The compounds produced by the isolates appeared to be lipid-polysaccharide complexes. Gas chromatograph analysis of the lipidic fraction of the bioemulsifiers from CLV20, CLOA40, and CLOA70 shows the prevalence of (9Z,12Z)-octadeca-9,12-dienoic acid, in concentrations of 42.8%, 25.9%, and 49.8%, respectively. The carbohydrate composition, as determined by GC-MS of their alditol acetate derivatives, showed a predominance of mannose, galactose, xylose and arabinose.

Sorption behaviour of bifenthrin on cork.

Biphentrin, a known pyrethroid, was studied, aiming its removal from aqueous solutions by granulated cork sorption. Batch experiments, either for equilibrium or for kinetics, with two granulated cork sizes were performed and results were compared with those obtained with of activated carbon sorption. Langmuir and Freundlich adsorption isotherms were obtained both showing high linear correlations. Bifenthrin desorption was evaluated for cork and results varied with the granule size of sorbent. The results obtained in this work indicate that cork wastes may be used as a cheap natural sorbent for bifenthrin or similar compounds removal from wastewaters.

Acid-base properties and solubility of pindolol, diazepam and chlordiazepoxide in SDS micelles.

The effect of sodium dodecyl sulphate (SDS) on the acid-base properties and on the solubility of a beta-blocker (pindolol) and of two benzodiazepines (diazepam and chlordiazepoxide) has been assessed. The study was performed by potentiometric and spectrophotometric determinations of the acidity constants and by spectrophotometric evaluation of the solubilities of the pharmaceutical drugs in aqueous solution and in solutions to which was added SDS with concentrations below and above the critical micelle concentration (cmc), at 25 degrees C and at an ionic strength 0.1 M (NaCl). The effect of the organized assemblies on the pKa values was quantified by the application of two theoretical models that differ in the inclusion of ionic exchange between positively charged species in solution. These models have allowed the determination of the binding constants for drug/micelle and yielded values in good agreement with those obtained by the solubility method, and in addition provide a more detailed picture of the effect of drug charge on its partition. The results can be taken to evidence different interaction modes of the drugs with the SDS micelles.