Transition of cellulose crystalline structure and surface morphology of biomass as a function of ionic liquid pretreatment and its relation to enzymatic hydrolysis

Cellulose is inherently resistant to breakdown, and the native crystalline structure (cellulose I) of cellulose is considered to be one of the major factors limiting its potential in terms of cost-competitive lignocellulosic biofuel production. Here we report the impact of ionic liquid pretreatment on the cellulose crystalline structure in different feedstocks, including microcrystalline cellulose (Avicel), switchgrass (Panicum virgatum), pine ( Pinus radiata ), and eucalyptus ( Eucalyptus globulus ), and its influence on cellulose hydrolysis kinetics of the resultant biomass. These feedstocks were pretreated using 1-ethyl-3-methyl imidazolium acetate ([C2mim][OAc]) at 120 and 160 °C for 1, 3, 6, and 12 h. The influence of the pretreatment conditions on the cellulose crystalline structure was analyzed by X-ray diffraction (XRD). On a larger length scale, the impact of ionic liquid pretreatment on the surface roughness of the biomass was determined by small-angle neutron scattering (SANS). Pretreatment resulted in a loss of native cellulose crystalline structure. However, the transformation processes were distinctly different for Avicel and for the biomass samples. For Avicel, a transformation to cellulose II occurred for all processing conditions. For the biomass samples, the data suggest that pretreatment for most conditions resulted in an expanded cellulose I lattice. For switchgrass, first evidence of cellulose II only occurred after 12 h of pretreatment at 120 °C. For eucalyptus, first evidence of cellulose II required more intense pretreatment (3 h at 160 °C). For pine, no clear evidence of cellulose II content was detected for the most intense pretreatment conditions of this study (12 h at 160 °C). Interestingly, the rate of enzymatic hydrolysis of Avicel was slightly lower for pretreatment at 160 °C compared with pretreatment at 120 °C. For the biomass samples, the hydrolysis rate was much greater for pretreatment at 160 °C compared with pretreatment at 120 °C. The result for Avicel can be explained by more complete conversion to cellulose II upon precipitation after pretreatment at 160 °C. By comparison, the result for the biomass samples suggests that another factor, likely lignin-carbohydrate complexes, also impacts the rate of cellulose hydrolysis in addition to cellulose crystallinity.     

Secular trends in prevalence of overweight and obesity from 2006 to 2009 in urban asian Indian adolescents aged 14-17 years

The present study examines the secular trends in prevalence of overweight and obesity among urban Asian Indian adolescents in New Delhi (North India). The data were derived from cross-sectional sampling of children, 3493 in year 2006 and 4908 in year 2009, aged 14-17 years studying in privately-funded and government-funded schools. Age, gender and Asian Indian-specific cut offs of body mass index (BMI) were used to define overweight and obesity. The prevalence of obesity increased significantly from 9.8% in 2006 to 11.7% in 2009 (p<0.01), whereas underweight decreased from 11.3% to 3.9% (p<0.001). There was a significantly higher risk of being overweight (OR 1.28; 95% CI, 1.15-1.42) and obese (OR 1.44; 95% CI, 1.24-1.66) in year 2009 than 2006, after adjusting for age, gender and type of school. Males and privately-funded school children had significantly higher increase in prevalence and risk of being overweight and obese over the three years. In conclusion, this study showed an increasing trend in prevalence of overweight and obesity in urban Asian Indian adolescents. More specifically, the study showed the association of this increasing trend of overweight and obesity prevalence with male gender and high socio-economic status, calling for an urgent need for immediate and targeted preventive measures.     

Cost-effectiveness of 2009 pandemic influenza A(H1N1) vaccination in the United States

Background

Pandemic influenza A(H1N1) (pH1N1) was first identified in North America in April 2009. Vaccination against pH1N1 commenced in the U.S. in October 2009 and continued through January 2010. The objective of this study was to evaluate the cost-effectiveness of pH1N1 vaccination.

Methodology

A computer simulation model was developed to predict costs and health outcomes for a pH1N1 vaccination program using inactivated vaccine compared to no vaccination. Probabilities, costs and quality-of-life weights were derived from emerging primary data on pH1N1 infections in the US, published and unpublished data for seasonal and pH1N1 illnesses, supplemented by expert opinion. The modeled target population included hypothetical cohorts of persons aged 6 months and older stratified by age and risk. The analysis used a one-year time horizon for most endpoints but also includes longer-term costs and consequences of long-term sequelae deaths. A societal perspective was used. Indirect effects (i.e., herd effects) were not included in the primary analysis. The main endpoint was the incremental cost-effectiveness ratio in dollars per quality-adjusted life year (QALY) gained. Sensitivity analyses were conducted.

Results

For vaccination initiated prior to the outbreak, pH1N1 vaccination was cost-saving for persons 6 months to 64 years under many assumptions. For those without high risk conditions, incremental cost-effectiveness ratios ranged from $8,000–$52,000/QALY depending on age and risk status. Results were sensitive to the number of vaccine doses needed, costs of vaccination, illness rates, and timing of vaccine delivery.

Conclusions

Vaccination for pH1N1 for children and working-age adults is cost-effective compared to other preventive health interventions under a wide range of scenarios. The economic evidence was consistent with target recommendations that were in place for pH1N1 vaccination. We also found that the delays in vaccine availability had a substantial impact on the cost-effectiveness of vaccination.     

Different proposed applications of bacteriorhodopsin

Bacteriorhodopsin (BR) is an integral membrane protein found in "purple membrane" (the Archaea cell membrane) mainly in Halobacteria. This protein absorbs green light (wavelength 500-650 nm, with the absorption maximum at 568 nm) and converts it into an electrochemical gradient. This gradient in turn is used for ATP production. The ability of BR to convert light energy into chemical energy or sunlight into electricity has been used in different applications mainly optical appliances but also for therapeutic/medical applications and research. This review surveys some of these applications that have been patented in the last five years.     

RNA tertiary interactions mediate native collapse of a bacterial group I ribozyme

Large RNAs collapse into compact intermediates in the presence of counterions before folding to the native state. We previously found that collapse of a bacterial group I ribozyme correlates with the formation of helices within the ribozyme core, but occurs at Mg2+ concentrations too low to support stable tertiary structure and catalytic activity. Here, using small-angle X-ray scattering, we show that Mg2+-induced collapse is a cooperative folding transition that can be fit by a two-state model. The Mg2+ dependence of collapse is similar to the Mg2+ dependence of helix assembly measured by partial ribonuclease T1 digestion and of an unfolding transition measured by UV hypochromicity. The correspondence between multiple probes of RNA structure further supports a two-state model. A mutation that disrupts tertiary contacts between the L9 tetraloop and its helical receptor destabilized the compact state by 0.8 kcal/mol, while mutations in the central triplex were less destabilizing. These results show that native tertiary interactions stabilize the compact folding intermediates under conditions in which the RNA backbone remains accessible to solvent.     

Sodium selenite stimulates neurobehavior and neurochemical activities in rats

The effect of 0.05, 0.1, and 0.2 mg sodium selenite/kg body weight ip on the activities of neurobehavioral, acetyl cholinesterase, monoamine oxidase, and the content of dopamine and its metabolites in circadian rhythm centers of male Wistar rats was studied after 7 d of treatment. The results show an appreciable increase in locomotion, stereo-events, distance traveled, and average speed at the dose of 0.1 and 0.2 mg sodium selenite/kg. The data have shown hyperactivity of animals with various doses of sodium selenite, and it was significant and dose-dependent after 3 d of treatment. The activity of acetylcholinesterase (AChE) was inhibited dose dependently, and it was significant in preoptic area with 0.1 or 0.2 mg sodium selenite/kg. Conversely, in the posterior hypothalamus its activity was significantly elevated with the dose of 0.2 mg sodium selenite/kg, but its alteration in brain stem was not significant. Monoamine oxidase (MAO) activity was increased in preoptic area with the dose of 0.1 mg sodium selenite/kg, but its alteration in posterior hypothalamus and brain stem was not significant. The content of dopamine (DA), 3,4-dihydroxyphenyl acetic acid (DOPAC), and homovanilic acid (HVA) was elevated dose dependently and it was significant with the doss of 0.1 and 0.2 mg sodium selenite/kg, but the content of DOPAC and HVA in posterior hypothalamus was not significant with the dose of 0.1 mg sodium selenite/kg.     

Genetic and bioinformatic analysis of 41C and the 2R heterochromatin of Drosophila melanogaster: a window on the heterochromatin-euchromatin junction

Genomic sequences provide powerful new tools in genetic analysis, making it possible to combine classical genetics with genomics to characterize the genes in a particular chromosome region. These approaches have been applied successfully to the euchromatin, but analysis of the heterochromatin has lagged somewhat behind. We describe a combined genetic and bioinformatics approach to the base of the right arm of the Drosophila melanogaster second chromosome, at the boundary between pericentric heterochromatin and euchromatin. We used resources provided by the genome project to derive a physical map of the region, examine gene density, and estimate the number of potential genes. We also carried out a large-scale genetic screen for lethal mutations in the region. We identified new alleles of the known essential genes and also identified mutations in 21 novel loci. Fourteen complementation groups map proximal to the assembled sequence. We used PCR to map the endpoints of several deficiencies and used the same set of deficiencies to order the essential genes, correlating the genetic and physical map. This allowed us to assign two of the complementation groups to particular "computed/curated genes" (CGs), one of which is Nipped-A, which our evidence suggests encodes Drosophila Tra1/TRRAP.     

Deoxycholic acid activates the c-Jun N-terminal kinase pathway via FAS receptor activation in primary hepatocytes. Role of acidic sphingomyelinase-mediated ceramide generation in FAS receptor activation

We have shown previously that bile acids can activate the JNK pathway and down-regulate cholesterol 7alpha-hydroxylase (CYP7A1), the rate-limiting enzyme in the neutral pathway of bile acid biosynthesis. In this study, the mechanism(s) by which deoxycholic acid (DCA) activates the JNK pathway were examined. FAS receptor (FAS-R) and acidic sphingomyelinase (ASM)-deficient hepatocytes were resistant to DCA-induced activation of the JNK pathway. Activation of the JNK pathway (2-3-fold) in response to tumor necrosis factor-alpha was similar in both wild-type and FAS-R(-/-) hepatocytes. In wild-type and FAS-R(-/-) hepatocytes, ceramide elevation was detected as early as 2 min and peaked at 10 min after DCA treatment. In contrast, ASM(-/-) hepatocytes were defective in DCA-induced ceramide generation. Treatment with DCA resulted in movement of FAS-R to the cell surface, which was blocked upon treatment with brefeldin A. However, brefeldin A failed to block DCA-mediated JNK activation in wild-type hepatocytes. DCA-induced JNK activation was independent of either the epidermal growth factor receptor activation or free radical generation. Addition of ASM to rat hepatocytes activated JNK and down-regulated CYP7A1 mRNA levels. In conclusion, these results show that DCA activates JNK and represses CYP7A1 mRNA levels in primary hepatocytes via an ASM/FAS-R-dependent mechanism that is independent of either the epidermal growth factor receptor or free radical generation.     

Acetoxy drug: protein transacetylase of buffalo liver-characterization and mass spectrometry of the acetylated protein product

The purification and characterization of the buffalo liver microsomal transacetylase (TAase) catalyzing the transfer of acetyl groups from a model acetoxy drug: 7,8-diacetoxy-4-methylcoumarin (DAMC) to GST3-3 has been described here. The enzyme was routinely assayed using DAMC and cytosolic GST as the substrates and was partially purified from microsomes of the buffalo liver. The enzyme was found to have approximate molecular of weight 65 kDa. The action of TAase and DAMC on liver cytosolic GST resulted in the formation of monoacetoxymonohydroxy-4-methylcoumarin (MAMHC) and 7,8-dihydroxy-4-methylcoumarin (DHMC), although the former was the major metabolite. The buffalo liver microsomal TAase exhibited hyperbolic kinetics and yielded K(m) (1667 microM) and V(max) (192 units) when the concentration of DAMC was varied keeping the concentration of GST constant. After having characterized the nature of the substrates and a product of the TAase-catalyzed reaction, we set out to identify the acetylated protein which is another product of the reaction. GST3-3 was used as a model protein substrate for the action of TAase using DAMC as the acetyl donor. The subunit of control and modified GST3-3 were separated by SDS-polyacrylamide gel electrophoresis (PAGE) and digested with trypsin. The tryptic peptides were extracted from the gel pieces and analyzed by matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOFMS). The data search for calibrated and labeled mass peaks of peptides was performed on the Matrix Science Server using the search engine Mascot. The peptide maps so obtained covered 97% of the GST3-3 sequence. On comparison of MALDI peptide maps of modified and control GST, seven new peaks were recognized corresponding to the potentially acetylated peptides in peptide map. The mass value of each of them was 42 Da higher than the theoretical mass of a non-modified GST3-3 tryptic peptide, strongly suggesting acetylation. By examining the fragmentation patterns and by comparing experimental and predicted values for MS/MS daughter ions, the identity of the seven acetylated GST tryptic peptides could be confirmed by the application of LC/MS/MS. In the modified GST, N-terminal proline and six lysines (Lys(51), Lys(82), Lys(123), Lsy(181), Lys(191) and Lys(210)) were found to be acetylated. The structure of acetylated GST revealed that the lysines that underwent acetylation were peripheral in positions.