Cell-associated hemolytic activity in environmental strains of Plesiomonas shigelloides expressing cell-free, iron-influenced extracellular hemolysin

Hemolysis is a means of providing pathogenic bacteria with heme iron in vivo. In a previous work, iron-influenced hemolytic activity against sheep erythrocytes was detected in cell-free supernatants, but not in the cell fraction of two environmental Plesiomonas shigelloides strains incubated without shaking. Both strains have the hugA gene, which encodes an outer membrane receptor required for heme iron utilization. The present study was undertaken to investigate the expression of a second hemolytic activity detected during aerated incubation in normal and iron-depleted tryptone soya broth (id-TSB). An agar overlay procedure and doubling dilution titrations were employed to detect the hemolytic activity against several erythrocyte species. The kinetics of growth and hemolytic activity were assayed at 35 degrees C in aerated normal and id-TSB and salmon extract. Overlaid colonies showed a cell-associated beta-hemolytic activity within 4 h. For aerated cell-free supernatants, titers above 16 were not attained until 30 to 48 h of incubation; the best activity was noted with dog and mouse erythrocytes. After 24 h of aerated incubation, sonicated cells yielded high hemolytic activity against dog erythrocytes without activity in supernatants, but after 48 h, only 28 to 30% of the total activity remained cell associated. The hemolytic factor was released in broths during the death phase. Hemolytic activity was not detected in fish extract. This and other studies suggest that P. shigelloides may produce at least two hemolytic factors, their expression and detection being influenced by environmental growth conditions and testing procedures. The overlay assay appears to be the best routine method for detecting hemolytic activity in P. shigelloides.     

Sensory characteristics of Iberian dry-cured loins: Influence of crossbreeding and rearing system

The sensory characteristics of Iberian dry-cured loins and the influence of crossbreeding (pure Iberian - IB, Iberian female×Duroc male - IB×D and Duroc female×Iberian male - D×IB) and rearing system (outdoors fed on acorns and pasture - MON, indoors fed on concentrates high in oleic acid sunflower oil and supplemented with 250mg/kg of α-tocopherol acetate -HOVE- and indoors fed on control concentrates - CON) on sensory attributes were studied. Dry-cured loins from IB-MON and IB-HOVE pigs, which showed the highest intramuscular fat (IMF) content (p<0.01), reached higher scores for brightness, marbling traits (intensity, size and shape) and juiciness, and lower for hardness, dryness and fibrousness than loins from crossbred pigs (IB×D-HOVE, IB×D-CON and D×IB-HOVE). In fact, IMF content was positively linked to juiciness and marbling attributes and negatively to dryness, hardness and fibrousness, which was also observed in the principal component analysis (PCA). Neither the crossbreeding nor the rearing system seemed to influence odour, flavour and taste features. The PCA evidenced that dry-cured loins from IB-MON and IB-HOVE batches gathered together and were placed near to marbling attributes, juiciness and IMF content.     

Postpyloric enteral nutrition in the critically ill child with shock: a prospective observational study

Objective-

Insulin resistance (IR) is an important risk factor for type 2 Diabetes Mellitus (DM2) and cardiovascular disease (CVD). Metabolic Syndrome (MS) is a clustering of metabolic alterations associated to IR; however, there is no international consensus for defining its diagnosis. Our objective was to evaluate the prevalence and characteristics of MS identified by the ATP III and IDF criteria in adults from Talca city.

Research and methods-

We studied 1007 individuals, aged 18–74, and residents from Talca. MS subjects were defined according to ATP III (three altered factors) and IDF criteria (patients with waist circumference >80/90 cm (W/M) and two others altered factors).

Results-

The prevalence of metabolic syndrome according to the IDF and ATP III criteria was 36.4% and 29.5%, respectively after adjustment for age and sex. The agreement for both criteria was 89%. The prevalence in men was higher than in women for both MS definitions, although not significant. MS probability increased with age, and the highest risk was in the 57–68 age group (ATP-MS) and 53–72 age group (IDF-MS). Hypertension, high triglycerides and abdominal obesity are the most frequent alterations in MS.

Conclusion-

MS prevalence in adults was higher when diagnosed with IDF than with ATP criterion; in both, age is directly related with the MS presence. The MS subjects showed higher levels of blood pressure, waist circumference and plasma triglycerides. Considering our results, it is worrisome that one third of our population has a high risk of developing DM2 and CVD in the future.     

Can the periphery achieve core? The case of the automobile components industry in Spain

The paper analyses changes experienced by Spain as a European peripheral region in the automobile global value chain (GVC). Our attention is focused on both spatial concentration of value‐added and high‐skill activities, and generation of technology in the components industry. The analysis of plants set up (investments) and relocated (divestments) by multinationals (MNEs) between 2001 and 2010 shows that Spain is no longer a place for labour‐intensive activities and standardized processes using simple technologies in comparison with other peripheral regions. However, the continuing majority presence of foreign‐owned companies is limiting decision power for generating and transferring technology, concentrating it mainly in the areas in which Spanish MNEs are specialized.     

Hairpin-DNA probe for enzyme-amplified electrochemical detection of Legionella pneumophila

An electrochemical genosensor for the detection of nucleic acid sequences specific of Legionella pneumophila is reported. An immobilized thiolated hairpin probe is combined with a sandwich-type hybridization assay, using biotin as a tracer in the signaling probe, and streptavidin-alkaline phosphatase as reporter molecule. The activity of the immobilized enzyme was voltammetrically determined by measuring the amount of 1-naphthol generated after 2 min of enzymatic dephosphorylation of 1-naphthyl phosphate. The sensor allows discrimination between L. pneumophila and L. longbeachae with high sensitivity under identical assay conditions (no changes in stringency). A limit of detection of 340 pM L. pneumophila DNA, and a linear relationship between the analytical signal and the logarithm of the target concentration to 2 muM were obtained. Experimental results show the superior sensitivity and selectivity of the hairpin-based assay when compared with analogous sandwich-type assays using linear capture probes.     

Aluminium sulfate as coagulant for highly polluted cork processing wastewaters: removal of organic matter

This is the first part of a work on the chemistry of aluminium as coagulant in the treatment of highly polluted cork processing wastewater. The main aim of this first part was to determine the removal of organic matter - measured by reductions in chemical oxygen demand (COD), polyphenols (TP), and aromatic compounds (A) - that can be obtained using this physicochemical process. To this end, jar-test experiments were carried out to determine the optimal conditions for the process, in particular, the effective aluminium dosage, contamination level of wastewater, coagulant mixing time, stirring speed, and pH. The ranges of tested parameters for the coagulation process were: coagulant dose (33-166 mgL(-1) of Al(3+)), contamination of the wastewater (COD between 1060 and 3050 mgO(2)L(-1)), mixing time (5-30 min), stirring speed (60-300 rpm) and pH (4-11). The resulting removal capacities were in the ranges of 20-55% for COD, 28-89% for polyphenols, and 29-90% for aromatic compounds. The best results were obtained with a coagulant mixing time of 5 min and a stirring speed of 300 rpm. The optimal choices of pH and coagulant dose fundamentally depended on the contamination level of wastewater.     

Effect of acetate-free biofiltration with a potassium-profiled dialysate on the control of cardiac arrhythmias in patients at risk: a pilot study

Cardiac arrhythmias are a frequent event in chronic hemodialysis patients. The aim of this study was to evaluate the efficacy and safety of acetate-free hemofiltration with potassium-profiled dialysate (AFB-K) dialysis compared with constant potassium acetate-free biofiltration (AFB). Twelve patients (mean age 79 years) affected by cardiac arrhythmias or at a high risk for arrhythmia (advanced age, hypertension, left ventricular hypertrophy, heart valve disease, coronary artery disease, diabetes, paroxysmal atrial fibrillation) participated in a single-center, sequential cohort study. All were treated with hemodialysis 3 times per week, using constant potassium AFB for the first 3 weeks, followed by an AFB-K dialysate for the subsequent 3 weeks. The hemofilter, duration of dialysis, and electrolyte concentration were the same in both treatments. Both AFB-K and constant potassium AFB dialytic techniques were safe and well tolerated. The results of biochemical tests were similar, except for serum potassium levels after 2 hr of dialysis, which were significantly higher in the AFB-K group (4.0 mmol/L) than in the constant potassium AFB group (3.6 mmol/L) (p<0.001). All cardiac variables improved during AFB-K dialysis. There was a significant reduction of postdialysis QT intervals corrected for heart rate in the AFB-K group (448.8 ms) compared with the constant potassium AFB group (456.8 ms) (p=0.039). The severity and mean number of ventricular extasystoles also decreased (163.5 vs. 444.5/24 hr). Potassium profiling during hemodialysis treatment may be beneficial for patients with arrhythmias or at those risk of arrhythmias, particularly those with predialysis hyperkalemia.     

Effects of Fruit Position in Standard Place Pack Cartons and Gamma Irradiation on the Postharvest Quality of ‘Barnfield’ Navel Oranges

The objective of this study was to determine if oranges in the top and bottom layers within a Standard Place Pack were impacted differently by irradiation after long-term storage. ‘Barnfield’ Navel oranges were packed in Standard Place Pack cartons and treated with 0, 0.15, or 1 kGy of gamma irradiation. The fruit were stored for 3 weeks at 5 °C and then for 1 week at 20 °C. After storage, the fruit from the top and bottom layers were separately evaluated for quality. The development of stem-end rind breakdown (SERB) was the main cause of quality loss and was greater in irradiated fruit in the top layer. Fruit in the bottom layer showed more physical damage (flattening) but lower incidence of SERB. The changes in individual sugar content were minimal but significant for layer. The content of individual organic acids was consistently lower in irradiated fruit from the bottom layer. Layer type showed a stronger effect on phenolic compounds than irradiation dose. The tristimulus color, total soluble solids, titratable acidity, and firmness of fruit were not influenced by irradiation dose or layer type. The results show that damage in irradiated Navel oranges depends on dose and layer, with the top layers showing greater physiological damage and bottom layers showing more physical damage.     

Microstructural and photocatalytic characterization of cement-paste sol-gel synthesized titanium dioxide

A route for the in paste synthesis of TiO₂ loaded cement is described. TiO₂ sols are blended with fresh cement paste as an alternative process to add photocatalytic functionality to cement. The modification of cement paste structure after the addition of TiO₂ sols is analyzed by XRD, SEM and TGA. As a particular microstructural feature, TiO₂ containing calcium silicate hydrate (C-H-S) particles are identified as networking centers of a C-S-H gel fiber matrix. The increase of the TiO₂ sol concentration induces a decrease of pore size and an increase in the specific surface area in the cement composites. The photocatalytic activity of the TiO₂/cement system is evaluated from the degradation of Methylene Blue (MB) under UVirradiation, monitored through the absorbance at 665 nm. The results show that, although TiO₂ phases reveal no long range order structure, the cement paste exothermal treatment in presence of hydrate products and alkaline conditions leads to a photocatalytic composite. Such new cement matrix may be twofold advantageous since it additionally promotes the formation of C-S-H gel, main determinant of cement mechanical properties.