LR-90 prevents methylglyoxal-induced oxidative stress and apoptosis in human endothelial cells

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound known to induce cellular injury and cytoxicity, including apoptosis in vascular cells. Vascular endothelial cell apoptosis has been implicated in the pathophysiology and progression of atherosclerosis. We investigated whether the advanced glycation end-product inhibitor LR-90 could prevent MGO-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). HUVECs were pre-treated with LR-90 and then stimulated with MGO. Cell morphology, cytotoxicity and apoptosis were evaluated by light microscopy, MTT assay, and Annexin V-FITC and propidium iodide double staining, respectively. Levels of Bax, Bcl-2, cytochrome c, mitogen-activated protein kinases (MAPKs) and caspase activities were assessed by Western blotting. Reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. LR-90 dose-dependently prevented MGO-associated HUVEC cytotoxicity and apoptotic biochemical changes such as loss of MMP, increased Bax/Bcl-2 protein ratio, mitochondrial cytochrome c release and activation of caspase-3 and 9. Additionally, LR-90 blocked intracellular ROS formation and MAPK (p44/p42, p38, JNK) activation, though the latter seem to be not directly involved in MGO-induced HUVEC apoptosis. LR-90 prevents MGO-induced HUVEC apoptosis by inhibiting ROS and associated mitochondrial-dependent apoptotic signaling cascades, suggesting that LR-90 possess cytoprotective ability which could be beneficial in prevention of diabetic related-atherosclerosis.     

Isolation and characterization of butachlor‐catabolizing bacterial strain Stenotrophomonas acidaminiphila JS‐1 from soil and assessment of its biodegradation potential

Aims: Isolation, characterization and assessment of butachlor‐degrading potential of bacterial strain JS‐1 in soil. Methods and Results: Butachlor‐degrading bacteria were isolated using enrichment culture technique. The morphological, biochemical and genetic characteristics based on 16S rDNA sequence homology and phylogenetic analysis confirmed the isolate as Stenotrophomonas acidaminiphila strain JS‐1. The strain JS‐1 exhibited substantial growth in M9 mineral salt medium supplemented with 3·2 mmol l^?1 butachlor, as a sole source of carbon and energy. The HPLC analysis revealed almost complete disappearance of butachlor within 20 days in soil at a rate constant of 0·17 day^?1 and half‐life (t_½) of 4·0 days, following the first‐order rate kinetics. The strain JS‐1 in stationary phase of culture also produced 21·0 μg ml^?1 of growth hormone indole acetic acid (IAA) in the presence of 500 μg ml^?1 of tryptophan. The IAA production was stimulated at lower concentrations of butachlor, whereas higher concentrations above 0·8 mmol l^?1 were found inhibitory. Conclusions: The isolate JS‐1 characterized as Stenotrophomonas acidaminiphila was capable of utilizing butachlor as sole source of carbon and energy. Besides being an efficient butachlor degrader, it substantially produces IAA. Significance and Impact of the Study: The bacterial strain JS‐1 has a potential for butachlor remediation with a distinctive auxiliary attribute of plant growth stimulation.     

Plants at high altitude exhibit higher component of alternative respiration

Total respiration, capacities of cytochrome (CytR) and alternative respiration (AR) were studied in two varieties of barley (Horedum vulgare) and wheat (Triticum aestivum) each and one variety of pea (Pisum sativum) at low (Palampur; 1300 m) and high altitudes (Kibber; 4200 m). Similar studies were carried out in naturally growing Rumex nepalensis and Trifoilum repenses at Palampur, Palchan (2250 m) and Marhi (3250 m). All the plants species exhibited lower CytR but significantly higher AR capacity at high altitude (HA) (72-1117% higher) as compared to those at low altitude (LA). Glycolytic product, pyruvate and tricarboxylic acid cycle intermediate, citrate increased with increase in altitude. While the role of these metabolites in relation to HA biology is discussed, significantly higher AR at HA is proposed to be an adaptive mechanism against the metabolic perturbations wherein it might act to lower reactive oxygen species and also provides metabolic homeostasis to plants under the environment of HA.     

Two alternative conformations of S-adenosyl-L-homocysteine bound to Escherichia coli DNA adenine methyltransferase and the implication of conformational changes in regulating the catalytic cycle

The crystal structure of the Escherichia coli DNA adenine methyltransferase (EcoDam) in a binary complex with the cofactor product S-adenosyl-L-homocysteine (AdoHcy) unexpectedly showed the bound AdoHcy in two alternative conformations, extended or folded. The extended conformation represents the catalytically competent conformation, identical to that of EcoDam-DNA-AdoHcy ternary complex. The folded conformation prevents catalysis, because the homocysteine moiety occupies the target Ade binding pocket. The largest difference between the binary and ternary structures is in the conformation of the N-terminal hexapeptide ((9)KWAGGK(14)). Cofactor binding leads to a strong change in the fluorescence of Trp(10), whose indole ring approaches the cofactor by 3.3A(.) Stopped-flow kinetics and AdoMet cross-linking studies indicate that the cofactor prefers binding to the enzyme after preincubation with DNA. In the presence of DNA, AdoMet binding is approximately 2-fold stronger than AdoHcy binding. In the binary complex the side chain of Lys(14) is disordered, whereas Lys(14) stabilizes the active site in the ternary complex. Fluorescence stopped-flow experiments indicate that Lys(14) is important for EcoDam binding of the extrahelical target base into the active site pocket. This suggests that the hexapeptide couples specific DNA binding (Lys(9)), AdoMet binding (Trp(10)), and insertion of the flipped target base into the active site pocket (Lys(14)).     

Factor H binding and function in sialylated pathogenic neisseriae is influenced by gonococcal, but not meningococcal, porin

Neisseria gonorrhoeae and Neisseria meningitidis both express the lacto-N-neotetraose (LNT) lipooligosaccharide (LOS) molecule that can be sialylated. Although gonococcal LNT LOS sialylation enhances binding of the alternative pathway complement inhibitor factor H and renders otherwise serum-sensitive bacteria resistant to complement-dependent killing, the role of LOS sialylation in meningococcal serum resistance is less clear. We show that only gonococcal, but not meningococcal, LNT LOS sialylation enhanced factor H binding. Replacing the porin (Por) B molecule of a meningococcal strain (LOS sialylated) that did not bind factor H with gonococcal Por1B augmented factor H binding. Capsule expression did not alter factor H binding to meningococci that express gonococcal Por. Conversely, replacing gonococcal Por1B with meningococcal PorB abrogated factor H binding despite LNT LOS sialylation. Gonococcal Por1B introduced in the background of an unsialylated meningococcus itself bound small amounts of factor H, suggesting a direct factor H-Por1B interaction. Factor H binding to unsialylated meningococci transfected with gonococcal Por1B was similar to the sialylated counterpart only in the presence of higher (20 microg/ml) concentrations of factor H and decreased in a dose-responsive manner by approximately 80% at 1.25 microg/ml. Factor H binding to the sialylated strain remained unchanged over this factor H concentration range however, suggesting that LOS sialylation facilitated optimal factor H-Por1B interactions. The functional counterpart of factor H binding showed that sialylated meningococcal mutants that possessed gonococcal Por1B were resistant to complement-mediated killing by normal human serum. Our data highlight the different mechanisms used by these two related species to evade complement.     

Antimalarial drugs inhibiting hemozoin (beta-hematin) formation: a mechanistic update

Digestion of hemoglobin in the food vacuole of the malaria parasite produces very high quantities of redox active toxic free heme. Hemozoin (beta-hematin) formation is a unique process adopted by Plasmodium sp. to detoxify free heme. Hemozoin formation is a validated target for most of the well-known existing antimalarial drugs and considered to be a suitable target to develop new antimalarials. Here we discuss the possible mechanisms of free heme detoxification in the malaria parasite and the mechanistic details of compounds, which offer antimalarial activity by inhibiting hemozoin formation. The chemical nature of new antimalarial compounds showing antimalarial activity through the inhibition of hemozoin formation has also been incorporated, which may help to design future antimalarials with therapeutic potential against multi-drug resistant malaria.     

Chondroprotective potential of root extracts of <Emphasis Type="Italic">Withania somnifera</Emphasis> in osteoarthritis

This is the first report describing two novel chondroprotective activities of aqueous extracts of Withania somnifera root powder. First, these extracts had a statistically significant, short-term chondroprotective effect on damaged human osteoarthritic cartilage matrix in 50% of the patients tested. Second, these extracts caused a significant and reproducible inhibition of the gelatinase activity of collagenase type 2 enzyme in vitro.     

WHAT MOTIVATES WOMEN TO TAKE PART IN CLINICAL AND BASIC SCIENCE ENDOMETRIOSIS RESEARCH?*

BACKGROUND: The objective of this study was to identify factors motivating women to take part in endometriosis research and to determine if these factors differ for women participating in clinical versus basic science studies. METHODS: A consecutive series of 24 women volunteering for participation in endometriosis-related research were asked to indicate, in their own words, why they chose to volunteer. In addition, the women were asked to rate, on a scale of 0 to 10, sixteen potentially motivating factors. The information was gathered in the form of an anonymous self-administered questionnaire. RESULTS: Strong motivating factors (mean score > 8) included potential benefit to other women's health, improvement to one's own condition, and participation in scientific advancement. Weak motivating factors (mean score < 3) included financial compensation, making one's doctor happy, and use of 'natural' products. No difference was detected between clinical and basic science study participants. CONCLUSION: This study is the first study to specifically investigate the factors that motivate women to take part in endometriosis research. Understanding why women choose to take part in such research is important to the integrity of the informed consent process. The factors most strongly motivating women to participate in endometriosis research related to improving personal or public health; the weakest, to financial compensation and pleasing the doctor.