Resistin, a cysteine-rich adipocytokine, proposed as a link between obesity and diabetes in mice, was shown as a proinflammatory molecule in humans. We earlier reported that human resistin (hRes), a trimer, was resistant to heat and urea denaturation, existed in an oligomeric polydispersed state, and showed a concentrationdependent conformational change. These properties and an intimate correlation of hRes expression with cellular stress prompted us to investigate hRes as a possible chaperone. Here, we show that recombinant human resistin was able to protect the heat-labile enzymes citrate synthase and Nde1 from thermal aggregation and inactivation and was able to refold and restore their enzymatic activities after heat/guanidinium chloride denaturation. Furthermore, recombinant human resistin could bind misfolded proteins only. Molecular dynamics-based association-dissociation kinetics of hRes subunits pointed to resistin being a molecular chaperone. Bis-ANS, which blocks surface hydrophobicity, abrogated the chaperone activity of hRes, establishing the importance of surface hydrophobicity for chaperone activity. Replacement of Phe49 with Tyr (F49YhRes), a critical residue within the hydrophobic patch of hRes, although it could prevent thermal aggregation of citrate synthase and Nde1, was unable to refold and restore their activities. Treatment of U937 cells with tunicamycin/thapsigargin resulted in reduced hRes secretion and concomitant localization in the endoplasmic reticulum. Escherichia coli transformants expressing hRes could be rescued from thermal stress, pointing to hRes's chaperone-like function in vivo. HeLa cells transfected with hRes showed protection from thapsigargin-induced apoptosis. In conclusion, hRes, an inflammatory protein, additionally exhibited chaperone-like properties, suggesting a possible link between inflammation and cellular stress.protein folding | chaperokine R esistin, a small cysteine-rich secreted protein, is predominantly produced in human macrophages (1, 2). Resistin levels in human serum could neither be associated with obesity nor linked with insulin resistance (3), pointing to possible other role(s) for this hormone. We, and later others, showed that human resistin (hRes) is a proinflammatory molecule that stimulates the synthesis and secretion of TNF-α and IL-12 from macrophages through an NF-κB-activated pathway (4, 5). hRes mRNA levels are strongly induced by TNF-α and IL-6 in human peripheral blood mononuclear cells (6, 7). Although human and mouse resistin share 64.4 and 59% sequence homology at mRNA and amino acids levels, respectively, they differ considerably in terms of their structural organization (8). We earlier reported, based on extensive biophysical analyses, that recombinant human resistin (rhRes) is a highly stable molecule that exists in oligomeric states as a function of concentration with no major loss in helicity and displays slightly altered tertiary structure with an increase in temperature (9, 10). The variable oligomeric states and poly-dispersity...

An aerobic bacterium capable of breaking down the pesticide acephate ( O,S -dimethyl acetyl phosphoramidothioic acid) was isolated from activated sludge collected from a pesticide manufacturing facility. A phylogenetic tree based on the 16 S rRNA gene sequence determined that the isolate lies within the Pseudomonads. The isolate was able to grow in the presence of acephate at concentrations up to 80 mM, with maximum growth at 40 mM. HPLC and LC-MS/MS analysis of spent medium from growth experiments and a resting cell assay detected the accumulation of methamidophos and acetate, suggesting initial hydrolysis of the amide linkage found between these two moieties. As expected, the rapid decline in acephate was coincident with the accumulation of methamidophos. Methamidophos concentrations were maintained over a period of days, without evidence of further metabolism or cell growth by the cultures. Considering this limitation, strains such as described in this work can promote the first step of acephate mineralization in soil microbial communities.

A soil bacterium capable of utilizing methyl parathion as sole carbon and energy source was isolated by selective enrichment on minimal medium containing methyl parathion. The strain was identified as belonging to the genus Serratia based on a phylogram constructed using the complete sequence of the 16S rRNA. Serratia sp. strain DS001 utilized methyl parathion, p-nitrophenol, 4-nitrocatechol, and 1,2,4-benzenetriol as sole carbon and energy sources but could not grow using hydroquinone as a source of carbon. p-Nitrophenol and dimethylthiophosphoric acid were found to be the major degradation products of methyl parathion. Growth on p-nitrophenol led to release of stoichiometric amounts of nitrite and to the formation of 4-nitrocatechol and benzenetriol. When these catabolic intermediates of p-nitrophenol were added to resting cells of Serratia sp. strain DS001 oxygen consumption was detected whereas no oxygen consumption was apparent when hydroquinone was added to the resting cells suggesting that it is not part of the p-nitrophenol degradation pathway. Key enzymes involved in degradation of methyl parathion and in conversion of p-nitrophenol to 4-nitrocatechol, namely parathion hydrolase and p-nitrophenol hydroxylase component "A" were detected in the proteomes of the methyl parathion and p-nitrophenol grown cultures, respectively. These studies report for the first time the existence of a p-nitrophenol hydroxylase component "A", typically found in Gram-positive bacteria, in a Gram-negative strain of the genus Serratia.

Significance and Impact of the Study: A biocatalyst capable of degrading a wide range of organophosphate (OP) insecticides was generated by expressing an organophosphate degradation gene in Pseudomonas sp. Ind01 involved in mineralization of acephate. The biocatalyst can be used to eliminate a wide range of OP insecticide residues from the environment. AbstractOrganophosphate hydrolase (OPH), the product of an organophosphatedegrading (opd) gene cloned from Brevundimonas diminuta, hydrolyses the triester linkage found in neurotoxic organophosphate (OP) insecticides and nerve agents. Despite the fact that OPHs have a broad substrate range, OP compounds with a P-S linkage, such as insecticides like acephate, are poor substrates for the enzyme. Expression of OPH in acephate-utilizing Pseudomonas sp. Ind01 generated a live biocatalyst capable of degrading a wide range of OP insecticides. The heterologously expressed OPH, which is a substrate of twin arginine transport (Tat) pathway, successfully targeted to the membrane of Pseudomonas sp. Ind01. The membrane-associated OPH had a size that coincided with the mature form of OPH (mOPH), suggesting successful processing and targeting of the expressed OPH to the membrane. Pseudomonas sp. Ind01 expressing OPH degraded a variety of OP insecticides besides using acephate as sole carbon source.

Meta fission product (MFP) hydrolases catalyze hydrolysis of a low reactive carbon-carbon bond found in meta-fission products, generated during biodegradation of various aromatic compounds. These enzymes belong to the alpha/beta hydrolase super family and show structural conservation despite having poor sequence similarity. MFP-hydrolases are substrate specific and studies have indicated that this substrate specificity plays a key role in the determination of the organism's ability to degrade a particular substrate. In this concise review of MFP-hydrolases we discuss their classification, biochemical properties, the molecular basis of their substrate specificity, their catalytic mechanism, and evolutionary significance.

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India is the largest jute and fifth largest maize producing country in the world. In India maize is commonly stored and transported in jute bags which are used multiple times. Aflatoxin contamination of maize is a major issue in India. This study evaluated the potential impact of re-using jute bags on the risk of aflatoxin contamination of maize in the food supply chain. A total of 121 jute bags were collected in India; 95 had been used for maize and 26 bags were new. Significantly higher numbers of viable aflatoxigenic fungi were counted from re-used bags (27.8 times) (P<0.05), than the number from new bags. There was no significant difference between aflatoxin concentration found in the re-used jute bags and the new jute bags (P>0.05). Further analysis revealed that the aflatoxigenic fungal population (3.0 times) and aflatoxin concentration (1.2 times) were significantly higher in jute bags that had been used for maize with higher aflatoxin contamination (14-188.4 μg/kg total aflatoxins) than in those that had been used for maize with lower contamination (0.8-5.4 μg/kg total aflatoxins) (P<0.05). The significant positive correlation (P<0.05) between the aflatoxigenic fungal population of used jute bags and aflatoxin contamination of their packed maize indicated there is a risk of cross-contamination in the supply chain introduced by re-using jute bags. This is the first study to systematically reveal the potential impact of re-using jute bags on the fungal population and aflatoxin contamination risk. The application of readily applied treatments to re-used jute bags would help to minimise the aflatoxin contamination.

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