Stimulation of phosphate uptake and polyphosphate accumulation by activated sludge microorganisms in response to sulfite addition

Enhanced phosphate removal from wastewaters is dependent on the synthesis and intracellular accumulation of polyphosphate by sludge microorganisms. However the role played by polyphosphate in microbial metabolism and the factors that trigger its formation remain poorly-understood. Many examples of the accumulation of the biopolymer by environmental microorganisms are documented; these include a recent report of the presence of large polyphosphate inclusions in sulfur-oxidizing marine bacteria. To investigate whether any link might exist outside the marine environment between the presence of reduced sulfur compounds and enhanced levels of microbial phosphate uptake and polyphosphate accumulation, activated sludge cultures were grown under laboratory conditions in media that contained sulfite, thiosulfate, hydrosulfite or tetrathionate. Only in the presence of sulfite was there any evidence of a stimulatory effect; in medium that contained 0.5 mM sodium sulfite some 17% more phosphate was removed by the sludge, whilst there was an almost two-fold increase in intracellular polyphosphate levels. No indications of sulfite toxicity were observed.

Pilot-scale evaluation of the application of low pH-inducible polyphosphate accumulation to the biological removal of phosphate from wastewaters.

To investigate the possible biotechnological application of the phenomenon of low pH-inducible phosphate uptake and polyphosphate accumulation, previously reported using pure microbial cultures and under laboratory conditions, a 2000 L activated sludge pilot plant was constructed at a municipal sewage treatment works. When operated as a single-stage reactor this removed more than 60% of influent phosphate from primary settled sewage at a pH of 6.0, as opposed to approximately 30% at the typical operational pH for the works of 7.0-7.3-yet without any deleterious effect on other treatment parameters. At these pH values the phosphorus content of the sludge was, respectively, 4.2% and 2.0%. At pH 6.0 some 33.9% of sludge microbial cells were observed to contain polyphosphate inclusions; the corresponding value at pH 7.0 was 18.7%. Such a process may serve as a prototype for the development of alternative biological and chemical options for phosphate removal from wastewaters.

Significance of peroxisome proliferator-activated receptors in the cardiovascular system in health and disease.

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear transcription factors that belong to the nuclear receptor superfamily. Three isoforms of PPAR have been identified, alpha, delta and gamma, which play distinct roles in the regulation of key metabolic processes, such as glucose and lipid redistribution. PPARalpha is expressed predominantly in the liver, kidney and heart, and is primarily involved in fatty acid oxidation. PPARgamma is mainly associated with adipose tissue, where it controls adipocyte differentiation and insulin sensitivity. PPARdelta is abundantly and ubiquitously expressed, but as yet its function has not been clearly defined. Activators of PPARalpha (fibrates) and gamma (thiazolidinediones) have been used clinically for a number of years in the treatment of hyperlipidaemia and to improve insulin sensitivity in diabetes. More recently, PPAR activation has been found to confer additional benefits on endothelial function, inflammation and thrombosis, suggesting that PPAR agonists may be good candidates for the treatment of cardiovascular disease. In this regard, it has been demonstrated that PPAR activators are capable of reducing blood pressure and attenuating the development of atherosclerosis and cardiac hypertrophy. This review will provide a detailed discussion of the current understanding of basic PPAR physiology, with particular reference to the cardiovascular system. It will also examine the evidence supporting the involvement of the different PPAR isoforms in cardiovascular disease and discuss the current and potential future clinical applications of PPAR activators.

The C-terminal kinase domain of the p34cdc2-related PITSLRE protein kinase (p110C) associates with p21-activated kinase 1 and inhibits its activity during anoikis.

The PITSLRE protein kinases are parts of the large family of p34cdc2-related kinases. During apoptosis induced by some stimuli, specific PITSLRE isoforms are cleaved by caspase to produce a protein that contains the C-terminal kinase domain of the PITSLRE proteins (p110C). The p110C induces apoptosis when it is ectopically expressed in Chinese hamster ovary cells. In our study, similar induction of this p110C was observed during anoikis in NIH3T3 cells. To investigate the molecular mechanism of apoptosis mediated by p110C, we used the yeast two-hybrid system to screen a human fetal liver cDNA library and identified p21-activated kinase 1 (PAK1) as an interacting partner of p110C. The association of p110C with PAK1 was further confirmed by in vitro binding assay, in vivo coimmunoprecipitation, and confocal microscope analysis. The interaction of p110C with PAK1 occurred within the residues 210-332 of PAK1. Neither association between p58PITSLRE or p110PITSLRE and PAK1 nor association between p110C and PAK2 or PAK3 was observed. Anoikis was increased and PAK1 activity was inhibited when NIH3T3 cells were transfected with p110C. Furthermore, the binding of p110C with PAK1 and inhibition of PAK1 activity were also observed during anoikis. Taken together, these data suggested that PAK1 might participate in the apoptotic pathway mediated by p110C.

Thiazolidinediones: effects on insulin resistance and the cardiovascular system.

Abstract
Thiazolidinediones (TZDs) have been used for the treatment of hyperglycaemia in type 2 diabetes for the past 10 years. They may delay the development of type 2 diabetes in individuals at high risk of developing the condition, and have been shown to have potentially beneficial effects on cardiovascular risk factors. TZDs act as agonists of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) primarily in adipose tissue. PPAR-gamma receptor activation by TZDs improves insulin sensitivity by promoting fatty acid uptake into adipose tissue, increasing production of adiponectin and reducing levels of inflammatory mediators such as tumour necrosis factor-alpha (TNF-alpha), plasminogen activator inhibitor-1(PAI-1) and interleukin-6 (IL-6). Clinically, TZDs have been shown to reduce measures of atherosclerosis such as carotid intima-media thickness (CIMT). However, in spite of beneficial effects on markers of cardiovascular risk, TZDs have not been definitively shown to reduce cardiovascular events in patients, and the safety of rosiglitazone in this respect has recently been called into question. Dual PPAR-alpha/gamma agonists may offer superior treatment of insulin resistance and cardioprotection, but their safety has not yet been assured

Textile wastewater treatment using granular activated carbon adsorption in fixed beds

This work involved the treatment of industrial wastewater from a nylon carpet printing plant which currently receives no treatment and is discharged to sea. As nylon is particularly difficult to dye, acid dyes are required for successful coloration and cause major problems with the plant's effluent disposal in terms of color removal. Granular activated carbon Filtrasorb 400 was used to treat a ternary solution of acid dyes and the process plant effluent containing the dyes in a fixed-bed column system. Experimental data were correlated using the bed depth service time (BDST) model to previously published work by the authors for single dye adsorption. The results were expressed in terms of the BDST adsorption capacity, in milligrams of adsorbate per gram of adsorbent, and indicated that there was a 12-25% decrease iri adsorption capacity in the ternary system compared to the single component system; This reduction has been attributed to competitive adsorption occurring in the ternary component system. Dye adsorption from the process plant effluent showed an approximate 65% decrease in adsorption capacity compared to the ternary solution system. This has been attributed to interference caused by the other colorless textile effluent pollutants found in the process wastewater. A chemical oxygen demand analysis on these components indicated that the dyes accounted for only 14% of the total oxygen demand.

CsF and alumina: A mixed homogeneous-heterogeneous catalytic system for the transesterification of sunflower oil with methanol

The activity and nature (i e heterogeneous and/or homogeneous) of catalysts based on CsF supported on alpha-Al2O3 were investigated for the transesterification of vegetable oil with methanol. The effect of the activation temperature, CsF loading and the reusability in a recirculating reactor were first studied CsF/alpha-Al2O3 exhibited the highest activity for a CsF loading of 0 6 mmol/g and when activated at 120 degrees C An important aspect of this study is the effect of CsF leaching into the reaction mixture, which is attributed to the high solubility of CsF in methanol, leading to a complete loss of activity after one run It was Identified that the activity of the catalyst resulted from a synergy between alumina and dissolved CsF, the presence of both compounds being absolutely necessary to observe any conversion The use of an alumina with a higher surface area resulted in a far greater reaction rate, showing that the concentration of surface site on the oxide (probably surface hydroxyl) was rate-limiting in the case of the experiments using the low surface area alpha-Al2O3 This work emphasizes that combined homogeneous-heterogeneous catalytic systems made from the blending of the respective catalysts can be used to obtain high conversion of vegetable oil to biodiesel. Despite the homogeneous/heterogeneous dual character, such a catalytic system may prove valuable in developing a simple and cost-effective continuous catalytic process for biodiesel production (C) 2010 Elsevier B V All rights reserved

Electrical, Thermal and Optical Diagnostics of an Atmospheric Plasma Jet System

Plasma diagnostics of atmospheric plasmas is a key tool in helping to understand processing performance issues. This paper presents an electrical, optical and thermographic imaging study of the PlasmaStream atmospheric plasma jet system. The system was found to exhibit three operating modes; one constricted/localized plasma and two extended volume plasmas. At low power and helium flows the plasma is localized at the electrodes and has the electrical properties of a corona/filamentary discharge with electrical chaotic temporal structure. With increasing discharge power and helium flow the plasma expands into the volume of the tube, becoming regular and homogeneous in appearance. Emission spectra show evidence of atomic oxygen, nitric oxide and the hydroxyl radical production. Plasma activated gas temperature deduced from the rotational temperature of nitrogen molecules was found to be of order of 400 K: whereas thermographic imaging of the quartz tube yielded surface temperatures between 319 and 347 K.

Chemical and mechanical stability of sodium sulfate activated slag after exposure to elevated temperature

The chemical and mechanical stability of slag activated with two different concentrations of sodium sulfate (Na₂SO₄) after exposure to elevated temperatures ranging from 200 to 800 °C with an increment of 200 °C has been examined. Compressive strengths and pH of the hardened pastes before and after the exposure were determined. The various decomposition phases formed were identified using X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. The results indicated that Na₂SO₄ activated slag has a better resistance to the degradation caused by exposure to elevated temperature up to 600 °C than Portland cement system as its relative strengths are superior. The finer slag and higher Na₂SO₄ concentration gave better temperature resistance. Whilst the pH of the hardened pastes decreased with an increase in temperature, it still maintained a sufficiently high pH for the protection of reinforcing bar against corrosion.

Temperature-regulated efflux pump/potassium antiporter system mediates resistance to cationic antimicrobial peptides in Yersinia

Most bacterial pathogens are resistant to cationic antimicrobial peptides (CAMPs) that are key components of the innate immunity of both vertebrates and invertebrates. In Gram-negative bacteria, the known CAMPs resistance mechanisms involve outer membrane (OM) modifications and specifically those in the lipopolysaccharide (LPS) molecule. Here we report, the characterization of a novel CAMPs resistance mechanism present in Yersinia that is dependent on an efflux pump/potassium antiporter system formed by the RosA and RosB proteins. The RosA/RosB system is activated by a temperature shift to 37 degrees C, but is also induced by the presence of the CAMPs, such as polymyxin B. This is the first report of a CAMPs resistance system that is induced by the presence of CAMPs. It is proposed that the RosA/RosB system protects the bacteria by both acidifying the cytoplasm to prevent the CAMPs action and pumping the CAMPs out of the cell.