Induction of oxalate binding by lipid peroxidation in rat kidney mitochondria.

Enhanced oxalate binding (150-180% of control) was observed in kidney, liver, brain and heart, after subjecting them to lipid peroxidation in presence of iron. Kidney mitochondrial oxalate binding was stimulated by different promoters, and the order of stimulation was Fe2+ greater than t-BH greater than ascorbic acid greater than Fe3+ greater than H2O2. Oxalate binding was maximum when iron concentration was between 1-2 mM. The iron-induced oxalate binding was inhibited by reduced glutathione, beta-mercaptoethanol, alpha-tocopherol and hydroxyl ion scavengers, histidine and mannitol. Catalase inhibited both Fe(2+)-H2O2 induced oxalate binding and lipid peroxidation reactions, suggesting that the induced oxalate binding in mitochondria was mediated through the hydroxyl radical reaction mechanism.     

Increased lipid peroxidation in kidney of vitamin B-6 deficient rats

Lipid peroxidation in kidney of rats fed with vitamin B-6 deficient diet for a period of 12 weeks was studied with pair-fed controls. The basal lipid peroxide level as well as the degree of susceptibility to lipid peroxidation in presence of promotors such as NADPH, ascorbate, t-butyl hydroperoxide, Fe2+, Cu2+ and oxalate, were increased in vitamin B-6 deficient kidney. The observed increased lipid peroxidation in vitamin B-6 deficient kidney was correlated with high levels of lipids, copper, iron, calcium and oxalate, low levels of antioxidants and antioxidant enzymes and increased levels of hydroperoxides and hydroxyl radicals.     

Induction of lipid peroxidation by oxalate in experimental rat urolithiasis

The function of lipid peroxidation and the antiperoxidative enzymes of rat liver and kidney were studied in stone formation induced by intraperitoneal administration of sodium oxalate (7 mg/100 g body weight). The animals sacrificed 3 and 12 h after administration of sodium oxalate had higher level of malondialdehyde in liver and kidney than control animals. A significantly pronounced release of malondialdehyde was observed in treated liver and kidney homogenates when incubated with either ferrous sulphate or hydrogen peroxide compared to control liver and kidney. Superoxide dismutase activity was increased only in liver and not in kidney in treated animals compared to the control. A highly significant decrease in catalase activity was observed in both liver and kidney of treated animals.     

Restoration of antioxidants in liver by methionine feeding in experimental rat urolithiasis.

The effect of methionine or citrate on antioxidant defense system has been studied in urolithic rat. Liver weight and its protein concentration did not change in the rats fed with calculi producing diet (CPD) when compared to normal diet fed rats. Feeding rats along with citrate (c-CPD) or methionine (m-CPD) improved their body weight gain. Liver microsomes and mitochondria fractions of CPD and c-CPD fed groups showed increased susceptibility for lipid peroxidation in presence of ascorbate and t-butyl hydroperoxide when compared to either control or m-CPD fed groups. Increased superoxide dismutase and xanthine oxidase activities, decreased catalase, glutathione peroxidase and glucose-6-phosphate dehydrogenase activities, decreased concentrations of reduced glutathione, total thiols, ascorbic acid and vitamin-E and increased formation of hydroxyl radical, hydroperoxides and diene conjugates were observed in the liver of both CPD fed group as well as c-CPD fed group. Except SOD and xanthine oxidase, all other parameters were normalized in m-CPD fed group. This suggested that feeding methionine reduced the susceptibility for lipid peroxidation by restoration of the level of free radical scavengers.     

Heterologous Expression of Oxalate Decarboxylase in <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> NC8

Lactic acid bacteria (LABs) are being used as a probiotic very often for various enteric problems. Many genetically modified LABs are created by different workers for various novel applications. In this study we examine the expression of heterologous oxalate decarboxylase (oxdc) in Lactobacillus plantarum NC8. Generally, this enzyme is not present in Lactobacillus spp. Oxdc gene from Bacillus subtilis was polymerase chain reaction-amplified and cloned in a shuttle vector pSIP400 series, downstream of the inducible promoter, P_orfx. In the presence of an inducing peptide, Sakacin-P, the expression of OxdC was observed in sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The cell-free extract and the purified protein from the recombinant LABs showed the presence of OxdC activity. The above recombinant LABs, with desired modifications, can be used as a possible probiotic for the degradation of intestinal dietary oxalate for preventing enteric hyperoxaluria.     

Photodynamic action of C-phycocyanins obtained from marine and fresh water cyanobacterial cultures: a comparative study using EPR spin trapping technique

C-phycocyanins, major biliproteins of blue green algae (cyanobacteria), widely used as colourants in food and cosmetics are known for their antioxidant as well as therapeutic potential. Recent claims indicating phycobiliproteins exert stronger photodynamic action on tumor cells than clinically approved hematoporphyrin derivatives motivate us to investigate the photodynamic action of two newly isolated C-phycocyanins from Phormidium [PHR] and Lyngbya [LY] spp, respectively in comparison with known C-phycocyanin from Spirulina sp. [SPI]. Photolysis of air saturated solutions of PHR, LY and SPI in the presence of 2,2,6,6-Tetramethyl piperidinol (TEMPL) generated three line EPR spectrum characteristic of 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxyl (TEMPOL). The increase in intensity of the EPR spectrum with time of irradiation and decrease in intensity, in the presence of 1O2 quencher DABCO confirm the formation of 1O2. Photoirradiation in the presence of spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) generated EPR signal characteristic of O2(-) adduct. Efficiency of 1O2 generation is of the order LY > PHR> SPI. The yield of reactive oxygen species (ROS) generation is found to be 1O2>O2(-) indicating type II mechanism to be the prominent pathway for photosensitation by phycocyanins.     

VKORC1 pharmacogenetics and pharmacoproteomics in patients on warfarin anticoagulant therapy: transthyretin precursor as a potential biomarker

BACKGROUND: Recognizing specific protein changes in response to drug administration in humans has the potential for the development of personalized medicine. Such changes can be identified by pharmacoproteomics approach based on proteomic technologies. It can also be helpful in matching a particular target-based therapy to a particular marker in a subgroup of patients, in addition to the profile of genetic polymorphism. Warfarin is a commonly prescribed oral anticoagulant in patients with prosthetic valve disease, venous thromboembolism and stroke. METHODS AND FINDING: We used a combined pharmacogenetics and iTRAQ-coupled LC-MS/MS pharmacoproteomics approach to analyze plasma protein profiles of 53 patients, and identified significantly upregulated level of transthyretin precursor in patients receiving low dose of warfarin but not in those on high dose of warfarin. In addition, real-time RT-PCR, western blotting, human IL-6 ELISA assay were done for the results validation. CONCLUSION: This combined pharmacogenomics and pharmacoproteomics approach may be applied for other target-based therapies, in matching a particular marker in a subgroup of patients, in addition to the profile of genetic polymorphism.     

DdrA,DdrD, and PprA: Components of UV and Mitomycin C Resistance in Deinococcus radiodurans R1

Mutants created by deleting the ddrA, ddrB, ddrC, ddrD, and pprA loci of Deinococcus radiodurans R1alone and in all possible combinations of pairs revealed that the encoded gene products contribute to this species’ resistance to UV light and/or mitomycin C. Deleting pprA from an otherwise wild type cell sensitizes the resulting strain to UV irradiation, reducing viability by as much as eight fold relative to R1. If this deletion is introduced into a ΔddrA or ΔddrD background, the resulting strains become profoundly sensitive to the lethal effects of UV light. At a fluence of 1000 Jm^-2, the ΔddrA ΔpprA and ΔddrD ΔpprA strains are 100- and 1000-fold more sensitive to UV relative to the strain that has only lost pprA. Deletion of ddrA results in a 100 fold increase in strain sensitivity to mitomycin C, but in backgrounds that combine a deletion of ddrA with deletions of either ddrC or ddrD, mitomycin resistance is restored to wild type levels. Inactivation of ddrB also increases D. radiodurans sensitivity to mitomycin, but unlike the ddrA mutant deleting ddrC or ddrD from a ΔddrB background further increases that sensitivity. Despite the effect that loss of these gene products has on DNA damage resistance, none appear to directly affect either excision repair or homologous recombination suggesting that they participate in novel processes that facilitate tolerance to UV light and interstrand crosslinks in this species.     

Effect of galangin supplementation on oxidative damage and inflammatory changes in fructose-fed rat liver

The study examined the effects of galangin (GA) on oxidative stress, inflammatory cytokine levels and nuclear factor-kappa B (NF-κB) activation in fructose-fed rat liver. Adult male albino Wistar rats were divided into 4 groups. Groups 1 and 4 received the control diet containing starch as the source of carbohydrate while groups 2 and 3 were fed a diet containing fructose. Groups 3 and 4 additionally received GA (100 μg/kg, p.o) from the 15th day. At the end of 60 days, the levels of plasma glucose, insulin and triglycerides, insulin sensitivity indices and oxidative stress markers in the liver were determined. Cytokines of interest were assayed by ELISA and RT-PCR and NF-κB p65 nuclear translocation by Western blot and RT-PCR. Compared to control diet-fed animals, fructose-fed animals developed hyperglycemia, hyperinsulinemia, hypertriglyceridemia and insulin resistance (IR) (all p < 0.01). GA prevented the rise in plasma glucose, insulin and triglycerides and improved insulin sensitivity. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels in plasma and the mRNA and protein levels of TNF-α and transforming growth factor-β1(TGF-β₁) in liver were significantly higher in fructose-fed rats than control rats. However, treatment with GA downregulated the expression of these cytokines. Translocation of NF-κB into the nucleus was also increased in fructose diet-fed animals, which was prevented by GA. These results suggest that GA prevents oxidative damage and has a downregulatory effect on the inflammatory pathway in liver of fructose-fed rats.     

Synthesis and properties of triazole-linked RNA

RNA oligonucleotides having triazole linkages between uridine and adenosine nucleosides have been prepared and studied using spectroscopic techniques. UV melting and CD showed that triazole strongly destabilized RNA duplex (7-14 °C per modification). NMR data suggested that, despite relative flexibility around the modified linkage, all base pairs were formed.