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This study reports the efficacy of cobalt preconditioning in preventing hypobaric hypoxia induced vascular leakage (an indicator of cerebral edema) using male Sprague-Dawley rats as model system. Exposure of animals to hypobaric hypoxia led to a significant increase in vascular leakage, reactive oxygen species (ROS), nitric oxide (NO), and vascular endothelial growth factor (VEGF) levels. There was a marked increase in Nuclear Factor kappaB (NFkappaB) DNA binding activity and levels of pro-inflammatory cytokines such as Monocyte chemoattractant protein (MCP-1), Interferon-gamma (IFN-gamma), Interleukin-1 (IL-1), and Tumor Necrosis Factor-alpha (TNF-alpha) and cell adhesion molecules such as Vascular Cell Adhesion Molecule-1 (VCAM-1), and P-selectin. Chemical preconditioning by cobalt for 7 days (12.5 mg Co/kg b.w., oral) significantly attenuated cerebral vascular leakage and the expression of inflammatory mediators induced by hypoxia. Administration of NFkappaB inhibitor, curcumin (50 mg/kg b.w.; i.p.) appreciably inhibited hypoxia induced vascular leakage indicating the involvement of NFkappaB in causing vascular leakage. Interestingly, cobalt when administered at 12.5 mg Co/kg b.w. (i.p.), 1 h before hypoxia could not prevent the vascular leakage indicating that cobalt per se did not have an effect on NFkappaB. The lower levels of NFkappaB observed in the brains of cobalt administered animals might be due to higher levels of antioxidant and anti-inflammatory proteins (hemeoxygenase-1 and metallothionein). To conclude cobalt preconditioning inhibited hypobaric hypoxia induced cerebral vascular leakage by lowering NFkappaB DNA binding activity and its regulated pro-inflammatory mediators. This is contemplated to be mediated by cobalt induced reduction in ROS/NO and increase in HO-1 and MT.

The present study reports the immunomodulatory effects of seabuckthorn (Hippophae rhamnoides L.) leaf extract on cellular and humoral immune response by studying delayed-type hypersensitivity response, IL-2, IL-4 and gamma-IFN levels and antibody titres in chromium-induced immunosuppressed animals. Oral feeding of chromium (30 mg/kg bw) significantly inhibited antibody production and S-RBC induced delayed-type hypersensitivity response. Administration of leaf extract (100 mg/kg bw) along with chromium significantly inhibited chromium-induced immunosuppression. To understand the immunomodulatory mechanism of leaf extract, in vitro studies were carried out using rat lymphocytes. Addition of chromium resulted in a significant decrease in lymphocyte size and increased ROS generation. The leaf extract of seabuckthorn significantly inhibited chromium-induced reactive oxygen species (ROS) generation and maintained the cell size identical to that of control cells. Chromium treatment markedly inhibited the mitochondrial transmembrane potential by larger lymphocytes in particular, while the leaf extract restored the same significantly. Chromium also inhibited significantly concanavalin A (ConA) induced IL-2, IL-4 and gamma-IFN production in rat lymphocytes. The leaf extract (100 microg/ml) alone stimulated IL-2 and gamma-IFN production even in the absence of ConA and also inhibited chromium-induced decline in IL-2 and gamma-IFN production but it did not change IL-4 production. These observations suggest that the leaf extract of seabuckthorn has significant immunomodulatory activity and specifically activates the cell-mediated immune response.

This paper relates to a process for preparation of polyaniline salts such as polyaniline-sulfate, polyaniline-nitrate and polyaniline-hydrochloride by emulsion polymerization pathway. Aniline was oxidized to polyaniline salt using benzoyl peroxide as an oxidizing agent in the presence of sulfuric, nitric, or hydrochloric acid by emulsion polymerization pathway. Polyaniline salts and their corresponding bases were characterized by infrared, electronic absorption, X-ray diffraction spectral techniques, scanning electron microscope, X-ray photoelectron, elemental analysis and conductivity measurement. The results of this study indicate that both acid and surfactant group are present in the polyaniline salt as dopants. The values of yield were found to be 59.6, 55.0 and 53.9% for polyaniline-sulfate, polyaniline-nitrate and polyaniline-hydrochloride salt respectively. Conductivity of the polyaniline-sulfate (0.08 S/cm) was found to be same as that of polyaniline-nitrate salt (0.08 S/cm) and however, one order of magnitude lower conductivity was obtained for polyaniline-hydrochloride salt (0.004 S/cm). The semiconducting range (10−1 to 10−4 S/cm) can be used for EMI shielding and antistatic applications.

The present study reports the antioxidant activity of Seabuckthorn (Hippophae rhamnoides), family Elaegnaceae, on chromium induced oxidative stress in male albino rats. Oxidative stress was induced in the rats by force-feeding of potassium dichromate equivalent to a dose of 30 mg/kg body weight (BW) of chromium(VI) for 30 days. Administration of chromium decreased the body weight and increased organ to body weight ratio significantly. Chromium treatment significantly decreased reduced glutathione (GSH), and increased malondialdehyde (MDA) and creatine phosphokinase (CPK) levels; further it also enhanced glutamate oxaloacetate transferase (GOT) and glutamate pyruvate transferase (GPT) levels in the serum. Different doses of the alcoholic leaf extract of Seabuckthorn were evaluated for the protection against the chromium induced oxidative stress. The results show that the leaf extract at a concentration of 100 and 250 mg/kg BW protected the animals from the chromium induced oxidative injury significantly.

Premna tomentosa (L. Verbanacae) is a widely used medicinal plant. Our earlier studies show that the extract of P. tomentosa leaves prevents acetaminophen-induced hepatotoxicity owing to its antioxidant property. In the present study, we have investigated the immunomodulatory effects of P. tomentosa extract against Chromium (VI) induced immunosuppression in splenic lymphocytes. Chromium (Cr) addition at a concentration of 5 microg showed an increase in cytotoxicity, apoptosis and reactive oxygen species (ROS) and a decrease in lymphocyte proliferation and antioxidant levels, whereas pre-treatment of the cells with P. tomentosa extract (at 500 microg concentration) resulted in decreased cytotoxicity and ROS levels. Further, the drug treatment also maintained antioxidant levels and restored lymphocyte proliferation similar to that of control cells. The results indicated that the leaf extract of P. tomentosa has cytoprotective and immunomodulatory activities.

The present study reports the anti-oxidant activity of alcoholic extracts of leaf and fruit of seabuckthorn (SBT) on nitric oxide (NO) induced cytotoxicity in J-774 macrophages. Sodium nitroprusside (SNP), which generates NO at the concentration of 500 microg/ml, induced cytotoxicity as revealed by decreased neutral red uptake by macrophages. The cytotoxicity of SNP was attributed to enhanced reactive oxygen species (ROS) production, which in turn resulted in decrease in anti-oxidant levels. Alcoholic leaf and fruit extracts of SBT at the concentration of 500 microg/ml were found to have a significant cytoprotective effect against SNP-induced oxidative stress. These extracts inhibited SNP-induced cytotoxicity, free radical production and maintained the anti-oxidant status identical to that of control cells. The alcoholic fruit extract of SBT was found to have significantly higher anti-oxidant activity than leaf extract against SNP-induced cytotoxicity in murine macrophages.

This study was designed to determine the anti-oxidant and immunomodulatory properties of seabuckthorn (Hippophae rhamnoides) using lymphocytes as a model system. Chromium(VI) as potassium dichromate was used to induce oxidative damage. The production of free radicals by chromium and the ability of alcoholic leaf and fruit extracts of seabuckthorn to inhibit the oxidative damage induced by chromium was investigated. Addition of chromium (10 microg/ml) to the cells resulted in enhanced cytotoxicity, apoptosis, free radical production and decreased glutathione (reduced) levels. Chromium also caused a significant inhibition of lymphocyte proliferation induced by both lipopolysaccharide and concanavalin A. Alcoholic extracts of leaves and fruits of seabuckthorn at a concentration of 500 microg/ml were found to inhibit chromium-induced free radical production, apoptosis, DNA fragmentation and restored the anti-oxidant status to that of control cells. In addition, these extracts also were able to arrest the chromium-induced inhibition of lymphocyte proliferation. These observations suggest that the alcoholic extracts of leaves and fruits of seabuckthorn have marked cytoprotective properties, which could be attributed to the anti-oxidant activity.

The effect of Kombucha tea (KT) on oxidative stress induced changes in rats subjected to chromate treatment are reported. KT feeding alone did not show any significant change in malondialdehyde (MDA) and reduced glutathione (GSH) levels, but did enhance humoral response and delayed type of hypersensitivity (DTH) response appreciably over control animals. Chromate treatment significantly enhanced plasma and tissue MDA levels, decreased DTH response considerably, enhanced glutathione peroxidase and catalase activities; however, no change in GSH, superoxide dismutase and antibody titres was noticed. KT feeding completely reversed the chromate-induced changes. These results show that Kombucha tea has potent anti-oxidant and immunopotentiating activities.

Among 67 psychrotrophic bacterial isolates of Leh, India screened for production of hydrolytic enzymes at 10 °C, four belonging to Aeromonas hydrophila were characterized and evaluated for biodegradation of night soil. All strains produced metalloproteases on a variety of carbon and nitrogen sources. Strains LA1 and LA15 also produced α-amylase and PC5 both α- & β-amylase. No amylase was produced by PN7, however it produced lipase. Casein and glucose induced maximum enzyme activity (protease and amylase) in LA15 and PC5, respectively. In LA1, maximum induction of protease was observed with casein and of amylase with maltose. Corn oil/tributyrin served as the best inducers for protease and lipase production by PN7. A. hydrophila strains were found to be psychrotrophic with optimum growth and enzyme activity at 20 and 37 °C, respectively. Maximum biodegradation of night soil was observed by strain LA1 at 5–20 °C.

The present study reports on the effect of Fe2+, Ni2+ and CO2+ on anaerobic bacterial activity and dynamics during anaerobic mineralization of organic matter. Fe2+ stimulated biogas yield and methane content at 37 °C, but inhibited same marginally at low temperatures (10 and 20 °C). Ni2+ and CO2+ inhibited methane production; the toxicity increased with decreasing temperature. Fe2+ stimulated sulfate reducing bacterial (SRB) and methane producing bacterial (MPB) counts while Ni2+ and CO2+ inhibited the same. All the metals had no effect on obligate proton reducing bacterial (OPRB) counts. Fe2+ stimulated, Ni2+ severely and CO2+ appreciably inhibited H2 uptake and acetate/propionate utilization irrespective of presence/absence of sulfate. Thus, Ni2+ and CO2+ inhibited the overall anaerobic degradative process by inhibiting SRB and MPB activity.

The extracellular amylase produced by Clostridium thermocellum strain SS8 on starch was characterized as a β-amylase based on blue value reduction test and the production of maltose from starch. The enzyme had a temperature and pH optima of 60 o C and 6.0, respectively. Of the metal ions tested, Ca 2+ and Mg 2+ had little effect on enzyme activity, but their presence increased its thermal stability. Ca 2+ displayed a higher stabilizing effect and at 10 mmol l -1 Ca 2+ , the enzyme retained 86% activity even after exposure at 70 o C for 30 min. The amylase was induced on starch or maltose but was repressed strongly by glucose

Polyaniline salts have been used as catalysts for the tetrahydropyranylation of alcohols in a process being reported for the first time. The catalytic use of polyaniline salts is practical because of their easy preparation, recovery and reusability.

Effect of sulfate (20–60 m m ) and nitrate (5–20 m m )on anaerobic degradation of night soil is reported. With 3% volatile solids (VS), 20 m m sulfate enhanced biogas production two-fold at 10 and 20°C. The presence of sulfate promoted utilization of propionate, butyrate and valerate by sulfate-reducing bacteria and of acetate by acetoclastic methanogenic bacteria. In contrast, nitrate inhibited the methanogenesis and its effect increased directly with VS concentration and inversely with temperature. Sulfate increased the methanogenic count from 1·7 × 106 to 3·0 × 106 unlike nitrate which reduced the count from 3·3 × 105 to 1·0 × 104 ml−1.

This study was designed to determine the cytoprotective activity of flavones of seabuckthorn (Hippophae rhamnoides L.) against tert-butyl hydroperoxide (tert-BOOH), used as an oxidant to induce oxidative damage, with lymphocytes as the model system. Addition of tert-BOOH (250 microM) to the cells resulted in enhanced cytotoxicity and free radical production. The intracellular calcium levels, caspase activity, and apoptosis were significantly increased following tert-BOOH treatment. Seabuckthorn flavones at the concentration of 100 microg/mL significantly inhibited tert-BOOH-induced cytotoxicity and free radical production and also restored the antioxidant status to that of control cells. Seabuckthorn flavones also significantly restricted tert-BOOH-induced apoptosis by decreasing intracellular calcium levels and caspase activity. The extract also decreased tert-BOOH-induced formation of DNA breaks by 30%. These observations suggest that the flavones of seabuckthorn have marked cytoprotective properties, which could be attributed to the antioxidant activity.

Clostridium thermocellum strains SS8 and GS1 grew poorly on crude blopolymers but termented them easily after alkall treatment. With 1% alkall-extracted rice straw (AERS) and dellgnified bamboo pulp (DBP), the ethanol-to-substrate (E/S) ratios were almost the same as those obtained when using fillter paper. Increasing the substrate concentrations decreased the percentage substrate degraded and the E/S ratio and concomitantly increased the amount of reducing sugars accumulated. A maximum amount of 8.6 g ethanol/l was produced by strain SS8 out of 37.5 g DBP degraded. Strain GS1 accumulated reducing sugars at substrate concentrations >50 g/l, thereby accounting for about 70% of AERS degraded. This strain produced cellulase on both cellulose and cellobiose. Both the strains grew in the presence of 1.5% (v/v) ethanol. Strain SS8 fermented starch, but the ethanol yield was low compared to that from cellulose. About 75% of starch degraded accumulated as reducing sugars at a substrate concentration of 40 g/l. The Inhibitory effects of ethanol (2 to 4%) were less drastic when growing cultures were challenged than when they were formed in situ. The effect of ethanol depended upon the phase of the culture.

In the present study, we report the molecular mechanisms of action by cobalt in facilitating acclimatization to hypobaric hypoxia using male Sprague-Dawley rats as the model system. We determined hypoxic gasping time and survival time as a measure to assess the degree of tolerance of animals to hypobaric hypoxia by exposing the animals to an altitude of 10,668 m. Oral administration of cobalt chloride (12.5 mg Co/kg body weight, BW, for 7 days) increased gasping time and hypoxic survival time by 3 to 4 times compared to the control animals. This could be attributed to an increased expression and the DNA binding activity of hypoxia inducible transcriptional factor (HIF-1alpha) and its regulated genes, that is, erythropoietin (EPO), vascular endothelial growth factor (VEGF), glucose transporter-1 (Glut-1), and nitric oxide synthase (NOS) levels. This in turn leads to better oxygenation, oxygen delivery, glucose transport, and maintenance of vascular tone, respectively, under oxygen-limited conditions. This was further confirmed by lower levels of lactate dehydrogenase (LDH) activity and lactate in the brain of cobalt + hypoxia group compared with animals exposed to hypoxia. Glucose levels also increased after cobalt supplementation. The findings of the study provide a basis for the possible use of cobalt for facilitating acclimatization to hypoxia and other conditions involving oxygen deprivation.

We have performed a ligand coordinate analysis to monitor the movement of the inhibitor SC-558 from the active site of the COX-2 protein to the exterior using molecular dynamics techniques. This study provides an insight into the intermolecular interactions formed by the ligand during this journey. The published crystal structure of COX-2 with SC-558 in the active site (1cx2) was taken, and the ligand was moved incrementally in 13 steps. At each of these points on the path, exhaustive minimization and dynamics calculations were performed. The role of water was found to be important in these computations. An average structure was obtained from 250 conformations at each point and minimized. At each point on the path, the 10 lowest-energy conformations were also selected; a consideration of the average and lowest conformations provides fine details on the consistency of specific and strong interactions, and also on the geometry of the ligand. The movement of the ligand through the protein may be divided into three stages that are distinguished from each other because of energy and geometry discontinuities in both the ligand and the protein. The first of these covers the region between the active site and the point at 5.8 A from it. The second, which covers the distance between 8.2 and 10.0 A and is associated with maximum energetic and structural instability, is of critical importance. The third stage covers the distance between 10.5 A and the exterior and represents a stage of increasing hydration and expulsion of the ligand from the protein. Our results provide a confirmation for the existence of a shallow cavity near the protein surface in which the ligand is bound reversibly. By examining the residues that show maximum mobility, one obtains an idea of the gating mechanism that governs the entry and exit of the protein into or from the deep pocket that contains the active site. We note, however, that the variation of the root-mean-square deviation of all residues begins to increase almost as soon as the ligand leaves the active site, and even before there are any changes in the gate inter-residue distances. This loosening of the protein even before the gate opens might be a part of the enthalpy-entropy balance that accompanies the ligand's passage through the protein. Our results provide an energy profile of the ligand during its entry/exit into/from the protein and can, in principle, enable one to assess the residence time, which in turn may be associated or indirectly correlated with adverse cardiovascular side effects of nonsteroidal anti-inflammatory drugs. We believe that similar analyses for other selected COX-2-specific inhibitors will provide a measure (or prediction) of possible toxicity effects.

tert-Butylhydroperoxide has been reported to inhibit growth and induce apoptosis in number of cell types, but little is known about the molecular mechanism mediating these effects. In the present study, we determined the molecular pathways that lead to apoptosis after treatment of cells with t-BOOH. The cells were exposed to different concentrations of t-BOOH (100–750 μM) for 1–4 h and various parameters such as cytotoxicity, ROS (reactive oxygen species) generation, MMP (mitochondrial membrane potential), intracellular Ca++ levels and expression of various proteins involved in apoptosis were determined. Exposure of U-937 cells to t-BOOH induced cytotoxicity in a time dependent manner with about 50% toxicity at 400 μM t-BOOH in 4 h. t-BOOH treatment resulted in a time dependent increase in reactive oxygen species levels, Ca++ influx and annexin V positive cells. There was a significant fall in MMP following exposure to t-BOOH with time. t-BOOH treatment of U-937 cells leads to apoptosis, which is accompanied by activation of caspase-3. The caspase-3 inhibitor (Ac-DEVD-CHO) inhibits the cytotoxicity induced by t-BOOH, indicating a direct link between caspase-3 activation and cell death. This activation of apoptosis is accompanied by release of cytochrome c, down regulation of anti-apoptotic protein Bcl-2 levels with concurrent increase in pro-apoptotic proteins Bax and Bad levels. These observations indicate that t-BOOH induces cell death in U-937 macrophages by apoptosis, which is mediated through mitochondrial pathway.

The present study reports cytoprotective and antioxidant activity of aqueous and alcoholic extracts of Rhodiola imbricata rhizome on tert-butyl hydroperoxide (tert-BHP) induced cytotoxicity in U-937 human macrophages. There was an increase in cytotoxicity and apoptosis significantly in the presence of tert-BHP over control cells. The tert-BHP induced cytotoxicity can be attributed to enhanced reactive oxygen species (ROS) production which in turn is responsible for fall in reduced glutathione (GSH) levels; further there was a significant decrease in mitochondrial potential and increase in apoptosis and DNA fragmentation. Both aqueous and alcoholic extracts of Rhodiola rhizome at a concentration of 250 microg/ml were found to inhibit tert-BHP induced free radical production, apoptosis and to restore the anti-oxidant levels to that of the control cells. The alcoholic extract of Rhodiola showed higher cytoprotective activities than aqueous extract. These observations suggest that the alcoholic and aqueous extracts of Rhodiola have marked cytoprotective and antioxidant activities.

The present study reports the cytoprotective and antioxidant properties of alcoholic leaf extract of seabuckthorn (SBT) against hypoxia induced oxidative stress in C-6 glioma cells. Exposure of cells to hypoxia for 12 h resulted in a significant increase in cytotoxicity and decrease in mitochondrial transmembrane potential compared to the controls. Further an appreciable increase in nitric oxide and reactive oxygen species (ROS) production was noted which in turn was responsible for fall in intracellular antioxidant levels and GSH/GSSG ratio. There was a significant increase in DNA damage during hypoxia as revealed by comet assay. Pretreatment of cells with alcoholic leaf extract of SBT at 200 μg/ml significantly inhibited cytotoxicity, ROS production and maintained antioxidant levels similar to that of control cells. Further, the leaf extract restored the mitochondrial integrity and prevented the DNA damage induced by hypoxia. These results indicate that the leaf extract of SBT has strong antioxidant and cytoprotective activity against hypoxia induced oxidative injury. (Mol Cell Biochem 278: 9–14, 2005)

The cytoprotective and immunomodulating properties of Emblica officinalis (Amla) against chromium (VI) induced oxidative damage are reported. Chromium (VI) at 1 µg/mL concentration was highly cytotoxic. It enhanced free radical production and decreased reduced glutathione (GSH) levels and glutathione peroxidase (GPx) activity in macrophages. The presence of Amla resulted in an enhanced cell survival, decreased free radical production and higher antioxidant levels similar to that of control cells. Further, chromium (VI) treatment resulted in decreased phagocytosis and gamma-interferon (γ-IFN) production while Amla inhibited chromium induced immunosuppression and restored both phagocytosis and γ-IFN production by macrophages significantly. Copyright © 2003 John Wiley & Sons, Ltd.

The fruits extracts of Emblica officinalis (Amla) has been reported to have strong anti-oxidant properties. There is a paucity of studies on the immunomodulatory properties of fruit extracts of Amla in immuno-compromised states, with the emphasis on lymphocytes. Therefore, the aim of the study was to determine the anti-oxidant and immunomodulatory properties of Amla using chromium (VI) as an immunosuppressive agent. Chromium (Cr) treatment results in enhanced cytotoxicity, free radical production, lipid peroxidation and decreased glutathione peroxidase (GPx) activity and diminished glutathione (GSH) levels. There was a significant inhibition of both lipopolysaccharide and concanavalin-A-stimulated lymphocyte proliferation. Chromium also inhibited Con A stimulated interleukin-2 and gamma-interferon production significantly. Further, there was enhanced apoptosis and DNA fragmentation in the presence of Cr. Amla significantly inhibited Cr-induced free radical production and restored the anti-oxidant status back to control level. Amla also inhibited apoptosis and DNA fragmentation induced by Cr. Interestingly, Amla relieved the immunosuppressive effects of Cr on lymphocyte proliferation and even restored the IL-2 and gamma-IFN production considerably.

Anaerobic digestion of night soil was carried out in 25-litre digeters at 20°C. Digesters with 20–25 days HRT produced 23–28 litre biogas day−1 with 60–63% methane content. The volatile fatty acids and pH were maintained below 800 ppm and around 7·3, respectively. Batch studies at 5–30°C showed increased biogas production with temperature, and with volatile solids up to 6·2%. Volatile fatty acids, in general, increased directly with volatile solids and inversely with temperature. Microbial counts and enzyme activities in the stabilized digesters are also reported.

Clostridium thermocellum SS8 produced both carboxymethylcellulase (CMCase) and Avicelase when grown on cellulose. CMCase activity was unaffected by Ca(2+), Mg(2+), dithionate or dithiothreitol (DTT). Avicelase activity increased 2-fold with 5 mM DTT and 10 mM Ca(2+). Cellulase and amylase were produced when a celluloseadapted culture was grown on starch. The mould grew best on sucrose and was inhibited by NaCl above 10 g/l.