Biovalorization potential of peels of Ananas cosmosus (L.) Merr. for ethanol production by Pichia stipitis NCIM 3498 & Pachysolen tannophilus MTCC 1077.

Bioethanol, is a potential alternate source of energy, renewable and safe. Ethanol production from value added food and feedstock has also not shown growth as estimated. Of late, the second generation processes of production of ethanol, such as from lignocellulosic biomass out of agricultural/domestic waste has been gaining considerable momentum. Here, we explored a new approach for optimizing the conditions of physiochemical pretreatment as well as fermentation process using peels of Ananas cosmosus as substrate and immobilized yeast Pachysolen tannophilus MTCC.1077 and Pichia stipitis NCIM 3498. We have also studied the influence of process variables such as incubation temperature, inoculum concentration and different nutrients on ethanol production. Pulverized peels of A. cosmosus recorded 25 ± 0.31% cellulose, 28 ± 0.18% hemicellulose and 8 ± 0.07% of lignin on dry solid (DS) basis. Peels of A. cosmosus delignified with 1% H2SO4 yielded 18.89% glucose, 38.81% xylose and 29.31% fructose under thermochemical pretreatment using autoclave (121 degrees C, 20 min.), with a hydrolytic efficiency of 75.52 ± 0.45%. FTIR spectroscopy results not only indicated the penetration of H2SO4 in the amorphous region of the biomass and degradation of hemicelluloses but also showed the structural differences before and after pretreatment. The enzymes required for hydrolysis were prepared from culture supernatants of Trichoderma reesei NCIM 1052 using wheat bran as carbon source under submerged fermentation conditions on rotatory shaker incubator (at 28 degrees C for 10 days). Enzyme activity (U/ml) of crude cellulase produced by T. reesei NCIM 1052 was 311.1 µmole/ml/min. Delignified A. cosmosus peel yielded 51.71 ± 0.44 g/l glucose when enzymatically hydrolysed by crude cellulase at the substrate enzyme ratio of 1:5. Simultaneous saccharification and fermentation (SSF) of peels of A. cosmosus by crude cellulase and separately entrapped Pichia stipitis NCIM 3498 (now known as Scheffersomyces stipitis) and Pachysolen tannophilus MTCC 1077 cells in calcium alginate beads were also investigated in the present study. The fermentation experiments were carried out at flask level. The processing parameters setup for reaching a maximum response for ethanol production was obtained when applying the optimum values for temperature (32 degrees C), inoculum level (6%) and fermentation medium (ammonium sulphate, KH2PO4, peptone and yeast extract) for P. tannophilus MTCC 1077 and temperature (30 degrees C), inoculum level (2%) and fermentation medium (ammonium sulphate, KH2PO4, peptone and yeast extract) for S. stipitis NCIM 3498. Maximum ethanol concentration 10.5 g/l and 10.9 g/l was obtained from P. tannophilus MTCC 1077 and S. stipitis NCIM 3498, respectively at the optimized process conditions in anaerobic batch fermentation.

Transcription factor mce3R modulates antibiotics and disease persistence in Mycobacteriumtuberculosis.

Transcription factors (TFs) of Mycobacterium tuberculosis (Mtb), an etiological agent of tuberculosis, regulate a network of pathways that help prolong the survival of Mtb inside the host. In this study, we have characterized a transcription repressor gene (mce3R) from the TetR family, that encodes for Mce3R protein in Mtb. We demonstrated that the mce3R gene is dispensable for the growth of Mtb on cholesterol. Gene expression analysis suggests that the transcription of genes belonging to the mce3R regulon is independent of the carbon source. We found that, in comparison to the wild type, the mce3R deleted strain (Δmce3R) generated more intracellular ROS and demonstrated reduced susceptibility to oxidative stress. Total lipid analysis suggests that mce3R regulon encoded proteins modulate the biosynthesis of cell wall lipids in Mtb. Interestingly, the absence of Mce3R increased the frequency of generation of antibiotic persisters in Mtb and imparted in-vivo growth advantage phenotype in guinea pigs. In conclusion, genes belonging to the mce3R regulon modulate the frequency of generation of persisters in Mtb. Hence, targeting mce3R regulon encoded proteins could potentiate the current regimen by eliminating persisters during Mtb infection.

Investigating a putative transcriptional regulatory protein encoded by Rv1719 gene of Mycobacterium tuberculosis.

Mycobacterium tuberculosis, the causative agent of tuberculosis, demonstrates immense plasticity with which it adapts to a highly dynamic and hostile host environment. This is facilitated by a web of signalling pathways constantly modulated by a multitude of proteins that regulate the flow of genetic information inside the pathogen. Transcription factors (TFs) belongs to one such family of proteins that modulate the signalling by regulating the abundance of proteins at the transcript level. In the current study, we have characterized the putative transcriptional regulatory protein encoded by the Rv1719 gene of Mycobacterium tuberculosis. This TF belongs to the IclR family of proteins with orthologs found in both bacterial and archaeal species. We cloned the Rv1719 gene into the pET28a expression vector and performed heterologous expression of the recombinant protein with E coli as the host. Further, optimization of the purification protocol by affinity chromatography and characterization of proteins for their functional viability has been demonstrated using various biochemical and/or biophysical approaches. Scale-up of purification yielded approximately 30 mg of ~ 28 kDa protein per litre of culture. In-silico protein domain analysis of Rv1719 protein predicted the presence of the helix-turn-helix (HTH) domain suggesting its ability to bind DNA sequence and modulate transcription; a hallmark of a transcriptional regulatory protein. Further, by performing electrophoretic mobility shift assay (EMSA) we demonstrated that the protein binds to a specific DNA fragment harboring the probable binding site of one of the predicted promoters.

Emodin reverses CCl induced hepatic cytochrome P450 (CYP) enzymatic and ultrastructural changes: The in vivo evidence.

AIM: The curative effect of emodin (1,3,8-trihydroxy-6-methyl anthraquinone), an active compound of the plant species Ventilago maderaspatana Gaertn, was evaluated against carbon tetrachloride (CCl(4)) induced hepatic cytochrome P450 (CYP) enzymatic and ultrastructural alterations in rats. METHODS: Female rats were administered CCl(4) (1.5 mL/kg, ip) followed by varying doses of emodin (20, 30 and 40 mg/kg, oral po) after 24 h of CCl(4) administration. Animals were euthanized after 24 h of last administration to determine liver function tests in serum, hepatic light microscopic and ultrastructural changes, activity of CYP enzymes, microsomal lipid peroxidation and protein contents, hexobarbitone induced sleep time and bromosulphalein retention. RESULTS: The CCl(4) induced-toxic effects were observed with sharp elevation in the release of serum transaminases, alkaline phosphatase, lactate dehydrogenase and gamma-glutamyl transpeptidase. An initial study for an optimum dose of emodin among different dose levels revealed that a 30 mg/kg dose was effective in restoring all the enzymatic variables and liver histoarchitecture in a dose dependent manner. Exposure to CCl(4) diminished the activities of CYP enzymes (i.e. aniline hydroxylase and amidopyrine-N-demethylase and microsomal protein contents with concomitant increase in microsomal lipid peroxidation). Emodin at 30 mg/kg effectively reversed the CCl(4) induced hepatotoxic events, which was consistent with ultrastructural observations. Hexobarbitone-induced sleep time and plasma bromosulphalein retention also improved liver functions after emodin therapy. CONCLUSION: By reversal CYP activity and ultrastructural changes, emodin shows a strong hepatoprotective abilities.

Role of chelating agents and antioxidants in beryllium induced toxicity.

The present study was conducted to evaluate the therapeutic effectiveness of chelating agents [glutathione, 2,3 dimercapto propane sulfonic acid (DMPS) and D-penicillamine (DPA)] in combination with antioxidant (sodium selenite) in beryllium induced toxicity in female rats. A bolus dose of 50mg/kg-beryllium nitrate was administered singly followed by chelation therapy with GSH, DMPS + Se and DPA + Se at various durations of 1,3 and 7 days respectively. Results revealed a significant fall in the glycogen content, whereas, a marginal fall in the protein was also observed. The enzymatic activity of alkaline phosphatase and adenosine triphosphatase was depleted; on the contrary, there was a significant rise in the acid phosphatase and glucose-6-phosphatase pattern. A rise in the hepatic lipid peroxidation activity is a direct indication of oxidative damage resulting in free radical generation. The distribution of the metal by atomic absorption spectrophotometry revealed an increased concentration of beryllium in liver and kidney, followed by lung and uterus. The relative ability of three chelating agents to act as antagonists, for acute beryllium poisoning, have been examined in liver, kidney, lungs and uterus. The appreciable change in the beryllium concentration in various organs is duration dependent during the entire period being highly significant at 7 days regimen. Biochemical and distribution studies reveal that DPA + Se was the most effective therapeutic agent followed by DMPS + Se and GSH.

Analysis of time-dependent recovery from beryllium toxicity following chelation therapy and antioxidant supplementation.

Efforts have been made to minimize the toxic effect caused by beryllium. Adult cyclic rats of Sprague Dawley strain were administered a bolus dose of 50mg/kg beryllium nitrate intramuscularly. The chelation therapy with glutathione (GSH), dimercapto propane sulfonic acid (DMPS)+ selenium (Se) and D-Penicillamine (DPA) + Se was given for 3 days followed by a rest of 1,3 and 7 days respectively. The results revealed a significant fall in the blood sugar level, serum alkaline phosphatase activity, serum proteins. A significant rise in the transaminases i.e. aspartate aminotranferase and alanine aminotranferase pattern is indicative of leakage of enzymes from liver resulting in alterations in the cell permeability. A rise in the hepatic lipid peroxidation activity is a direct indication of oxidative damage resulting in free radical generation. Results of the distribution studies by atomic absorption spectrophotometry reveal an increased concentration of beryllium in liver and kidney followed by lung and uterus. The relative ability of 3 chelating agents to act as antagonists for acute beryllium poisoning have been examined in liver, kidney, lungs and uterus. The appreciable change in the beryllium concentration in various organs is duration-dependent during the entire period being highly significant after 7 days rest. From the biochemical assays, and distribution studies it can be assumed that DPA+Se was the most effective therapeutic agent followed by DMPS+Se and GSH. Thus it can be concluded that DPA+Se is a better therapeutic agent as compared to DMPS+Se and GSH.

An economic and ecological perspective of ethanol production from renewable agro waste: a review.

Agro-industrial wastes are generated during the industrial processing of agricultural products. These wastes are generated in large amounts throughout the year, and are the most abundant renewable resources on earth. Due to the large availability and composition rich in compounds that could be used in other processes, there is a great interest on the reuse of these wastes, both from economical and environmental view points. The economic aspect is based on the fact that such wastes may be used as low-cost raw materials for the production of other value-added compounds, with the expectancy of reducing the production costs. The environmental concern is because most of the agro-industrial wastes contain phenolic compounds and/or other compounds of toxic potential; which may cause deterioration of the environment when the waste is discharged to the nature. Although the production of bioethanol offers many benefits, more research is needed in the aspects like feedstock preparation, fermentation technology modification, etc., to make bioethanol more economically viable.

Therapeutic associated with occupational exposure to silica.

Occupational exposure to silica dust has been increasing the possible risk of varieties of pathologies. The aim of this study was to evaluate the protective activity of ethanolic extract of Glycyrrhiza glabra roots at doses of 500 and 1000 mg/kg, p.o., given for 7 days against the toxicity of SiO(2) nanoparticles (50mg/kg intraperitoneal for 6 weeks) in rats. Exposure to silica altered various respiratory and biochemical variables, including ALT, AST, albumin, urea, uric acid, creatinine, catalase, LPO and GSH. Treatments with G. glabra extract significantly improved antioxidant status towards control. Stone workers in the Gwalior region exposed to silica dust had higher prevalence of cough, wheezing and shortness of breath. Increased serum ACE level was noted in the silica exposed group. It is of immense need to monitor this problem for betterment of worker's health.

Hepatic endogenous defense potential of propolis after mercury intoxication.

Exposure to mercuric chloride (HgCl(2) ; 5 mg kg(-1) body weight; i.p.) induced oxidative stress in mice and substantially increased lipid peroxidation (LPO) and oxidized glutathione (GSSG) levels, decreased the level of reduced glutathione (GSH) and various antioxidant enzymes in liver and also increased the activities of liver marker enzymes in serum. Therapy with propolis extract, a resinous wax-like beehive product (200 mg kg(-1) orally, after mercury administration), for 3 days inhibited LPO and the formation of GSSG and increased the level of GSH in the liver. Release of serum transaminases, alkaline phosphatase, lactate dehydrogenase and γ-glutamyl transpeptidase were significantly restored after propolis treatment. The activities of antioxidant enzymes, that is, superoxide dismutase, catalase, glutathione-S-transferase and glucose-6-phosphate dehydrogenase, were also concomitantly restored towards normal levels after propolis administration. These observations clearly demonstrate that propolis treatment augments antioxidant defense against mercury-induced toxicity and provide evidence that propolis has therapeutic potential as a hepatoprotective agent.