Identification of two outer membrane proteins involved in the oxidation of sulphur compounds in Thiobacillus ferrooxidans

Abstract: Shift of three Thiobacillus ferrooxidans strains from Fe(II) to S⁰ or thiosulphate liquid medium caused distinctive changes in the outer membrane protein profile. In addition to a new 55-kDa protein which was synthesized only in the presence of sulphur compounds, a higher expression of a 47-kDa protein was observed. This latter protein appeared to be constitutively synthesized, since it was detectable in small amounts even in tile presence of ferrous iron as sole energy source, but its expression was greatly enhanced when elemental sulphur or thiosulphate were present in the growth medium.     

Structure/function studies of S100A8/A9

The functional importance of members of the S100 Ca²⁺-binding protein family is recently emerging. A variety of activities, several of which are apparently opposing, are attributed to S100A8, a protein implicated in embryogenesis, growth, differentiation, and immune and inflammatory processes. Murine (m) S100A8 was initially described as a chemoattractant (CP-10) for myeloid cells. It is coordinately expressed with mS100A9 (MRP14) in neutrophils and the non-covalent heterodimer is presumed to be the functional intracellular species. The extracellular chemotactic activity of mS100A8, however, is not dependent on mS100A9 and occurs at concentrations (10^-13–10^-11 M) at which the non-covalent heterodimer would probably dissociate. This review focuses on the structure and post-translational modifications of mS100A8/A9 and their effects on function, particularly chemotaxis.     

Factors affecting bioleaching kinetics of sulfide ores using acidophilic micro-organisms

Recovery of metal values from sulfide ores by use of acidophilic microorganisms is gaining importance. A number of commercial/pilot plants are setup to find out the techno-economic feasibility of the overall process. The main drawback in the process is the slow kinetics of dissolution of metal values from the sulfide ores. To make the technology e attractive the kinetics should be improved considerably. There are various factors which determine the overall kinetics such as bacterial activity and concentration, iron and sulfur oxidation, oxygen consumption, reactor design and nature of ore. A brief review has been made dealing with the above parameters     

GTP-Binding Regulatory Proteins in Higher Plant Cells

The exsitence of GTP-binding regulatory proteins (for short term, often refered as G-proteins) in higher plant cells is certain. G-proteins are classified into two groups based on their molecular structures, which are the heterotrimeric G-proteins (big G-proteins) that contain three different subunits and the small G-proteins that have only one subunit (monomeric G-proteins). All G-proteins are characterized by their properties to bind with and hydrolyze GTP, by which G-proteins function as transmembrane and intracellular signalling molecules. As a distinguished participant in signal transduction, G-proteins directly and/or indirectly regulate a number of physiological processes, such as regulation of phytochrome-related physiological processes and gene expression, involvement in blue-light response, K+-channel regulation, stomatal movement, hormone regulation, protein phosphrylation dephosphorylation, etc. Although G-proteins in plant cells have not been purified, the genes for a subunit of heterotrimeric G-proteins have been cloned. More evidences for the importance of G-proteins in plant signalling processes are rapidly accumulating.     

C6-oxidized cellulose: Ion interactions with mono- and divalent cations

The conformational behavior of different molecular weight fractions of a synthetic C6-oxidized derivative of cellulose were investigated by means of capillary viscometry, CD, and microcalorimetric measurements. Experiments were carried out in the presence of either monovalent or divalent counterions. The experimental data indicated that C6-oxidized cellulose can assume an ordered extended conformation at low ionic strength, induced by the intrachain repulsions of negative charges. This conformation was suggested to be very similar to the fully extended structure of cellulose. In addition to this, upon increasing the ionic strength, a conformational transition of the order-to-disorder type occurred. In fact, the screening of the electrostatic repulsions introduced a number of conformational kinks into the cellulosic backbone, which enabled the polymer to assume a more coiled conformation hence producing less viscous aqueous solutions. © 1998 John Wiley & Sons, Inc. Biopoly 45: 157–163, 1998     

Biooxidation of a gold-bearing pyrite-arsenopyrite concentrate

Abstract: Two years of BIOX pilot plant data have been examined for steady state conditions and then correlated using logistic kinetics. It was found that the logistic equation not only predicted the performance of individual stages but also the degree of biooxidation across the entire cascade of bioreactors. It was found that the rate constant was 1.3 day^-1 in the first three stages and 0.3 day^-1 in the fourth stage. The maximum removal constant was 0.90 in stage 1 and 0.99 in the remaining stages. Plant retention time ranged from 4 to 12 days with corresponding sulphide oxidation varying from 82 to 98% respectively, and primary stage removal rates varying from 8.9 to 4.4 kg m^-3 day^-l, respectively. In addition, batch biooxidation data were obtained. The biooxidation rate was found to be about half that for the continuous bioreactors. This is in agreement with the findings of several other workers. The specific rates of bioxidation of pyrite and arsenopyrite were very similar for the bulk concentrate at about 0.15 day^-1. However, it was significant that the biooxidation of arsenopyrite in the mixed mineral preceded that of pyrite, suggesting a sequential mechanism. Gold liberation was found to be linearly related to arsenopyrite biooxidation but oxidation of pyrite appears to be preferential in the gold-rich regions.     

ANGPTL4 regulate glutamine metabolism and fatty acid oxidation in nonsmall cell lung cancer cells

Angiopoietin‐like protein (ANGPTL) 4 is a key factor in the regulation of lipid and glucose metabolism in metabolic diseases. ANGPTL4 is highly expressed in various cancers, but the regulation of energy metabolism in tumours remains to be determined. This study explored the role of ANGPTL4 in aerobic glycolysis, glutamine consumption and fatty acid oxidation in nonsmall cell lung cancer (NSCLC) cells. Two NSCLC cell lines (A549 and H1299) were used to investigate the role of ANGPTL4 in energy metabolism by tracer techniques and with Seahorse XF technology in ANGPTLs4 knockdown cells. RNA microarrays and specific inhibitors were used to identify targets in ANGPTLs4‐overexpressing cells. The results showed that knockdown of ANGPTLs4 could inhibit energy metabolism and proliferation in NSCLC. ANGPTLs4 had no significant effect on glycolysis but affected glutamine consumption and fatty acid oxidation. Knockdown of ANGPTLs4 also significantly inhibited tumour metastasis and energy metabolism in mice and had a weak effect on glycolysis. RNA microarray analysis showed that ANGPTLs4 significantly affected glutaminase (GLS) and carnitine palmitoyl transferase 1 (CPT1). ANGPTLs4‐overexpressing cells were exposed to a glutamine deprivation environment, and cell proliferation and energy metabolism were significantly decreased but still differed from normal NSCLC cells. Treatment of ANGPTLs4‐overexpressing cells with GLS and CPT1 inhibitors simultaneously prevented the regulatory effects on cell proliferation and energy metabolism. ANGPTLs4 could promote glutamine consumption and fatty acid oxidation but not glycolysis or accelerate energy metabolism in NSCLC.     

Assessing Impacts of Hydropattern Restoration of an Overdrained Wetland on Soil Nutrients, Vegetation and Fire

Restoring hydrology to overdrained wetlands can facilitate restoration of degraded ecosystems. In the northern Everglades, the Rotenberger Wildlife Management Area (RWMA) became a rain-driven system as historic overland inflows were redirected. Consequently, the soil experienced severe drying, resulting in frequent muck fires, oxidation and a shift in vegetation composition. In July 2001, the RWMA hydropattern restoration began utilizing discharge from Stormwater Treatment Area 5 (STA-5), a constructed wetland. As a result, predischarge hydroperiods averaging 124 days increased to an average of 183 days. Soil total phosphorus (TP) concentrations in the topsoil layer did not significantly change from predischarge (637 mg/kg) to postdischarge (633 mg/kg) concentrations. Muck fires appear to be the catalyst for rapid alterations in the bioavailability and solubility of P. Prior to muck fires, soil P pools were 88% organic P and 12% inorganic P, shifting to 49% organic P and 51% inorganic P measured after a muck fire. Sawgrass ( Cladium jamaicense , OBL) and Cattail ( Typha domingensis , OBL) cover approximately 75% of the RWMA area as dominant or codominant species. Predischarge vegetation community composition documented obligate (OBL) and facultative wetland (FACW) species, each composing 46% of all species surveyed. Postdischarge vegetation compositions shifted to 59% OBL and 39% FACW species. In addition, there were significant elevations in tissue nutrient concentrations, TP, and total nitrogen, between pre- and postdischarge samples. An adaptive management approach to inflow and outflow operations will be an important part of successful wetland restoration.     

Azo dyes degradation by microorganisms – An efficient and sustainable approach

Synthetic aromatic compounds consisting of various functional groups are known as dyes. These colored compounds are often discharged in effluents, and they are very dangerous to aquatic life. Basically, the dye industry started by using natural plant and insect sources, and then suddenly turned into artificial manufacturing. Natural equilibrium of our environment gets changed by the reduction in photosynthetic activity due to the dyes. In China 900,000 tons of all kinds of dyes are usually produced, which are used in many industries like food, textile, food, paper and leather. Untreated wastewater contaminates aquatic bodies by causing eutrophication, change in water color, oxygen depletion which affect aquatic organisms to a great extent. Dye wastewater is now the key environmental pollution form. In recent eras an extensive study line has been developed to explore the dye decolorization and biodegradation under both aerobic as well as anaerobic conditions. In this review, the chemistry, toxicity and microbial biodegradation/decolorization are presented. Some recent studies along with the new techniques and methodologies of remediating the dye pollution are also discussed to provide the bases of their handling. Overall, efficient and high biodegradation potential make microbes an impending foundation for green chemistry to eradicate toxic dyes from industrial wastewater.