Obligatory role for phospholipase C-gamma(1) in villin-induced epithelial cell migration

While there is circumstantial evidence to suggest a requirement for phospholipase C-₁ (PLC-₁) in actin reorganization and cell migration, few studies have examined the direct mechanisms that link regulators of the actin cytoskeleton with this crucial signaling molecule. This study was aimed to examine the role that villin, an epithelial cell-specific actin-binding protein, and its ligand PLC-₁ play in migration in intestinal and renal epithelial cell lines that endogenously or ectopically express human villin. Basal as well as epidermal growth factor (EGF)-stimulated cell migration was accompanied by tyrosine phosphorylation of villin and its association with PLC-₁. Inhibition of villin phosphorylation prevented villin-PLC-₁ complex formation as well as villin-induced cell migration. The absolute requirement for PLC-₁ in villin-induced cell migration was demonstrated by measuring cell motility in PLC-₁^–/– cells and by downregulation of endogenous PLC-₁. EGF-stimulated direct interaction of villin with the Src homology domain 2 domain of PLC-₁ at the plasma membrane was demonstrated in living cells by using fluorescence resonance energy transfer. These results demonstrate that villin provides an important link between the activation of phosphoinositide signal transduction pathway and epithelial cell migration. fluorescence resonance energy transfer; actin     

A Novel Link between Fic (Filamentation Induced by cAMP)-mediated Adenylylation/AMPylation and the Unfolded Protein Response

The maintenance of endoplasmic reticulum (ER) homeostasis is a critical aspect of determining cell fate and requires a properly functioning unfolded protein response (UPR). We have discovered a previously unknown role of a post-translational modification termed adenylylation/AMPylation in regulating signal transduction events during UPR induction. A family of enzymes, defined by the presence of a Fic (filamentation induced by cAMP) domain, catalyzes this adenylylation reaction. The human genome encodes a single Fic protein, called HYPE (Huntingtin yeast interacting protein E), with adenylyltransferase activity but unknown physiological target(s). Here, we demonstrate that HYPE localizes to the lumen of the endoplasmic reticulum via its hydrophobic N terminus and adenylylates the ER molecular chaperone, BiP, at Ser-365 and Thr-366. BiP functions as a sentinel for protein misfolding and maintains ER homeostasis. We found that adenylylation enhances BiP''s ATPase activity, which is required for refolding misfolded proteins while coping with ER stress. Accordingly, HYPE expression levels increase upon stress. Furthermore, siRNA-mediated knockdown of HYPE prevents the induction of an unfolded protein response. Thus, we identify HYPE as a new UPR regulator and provide the first functional data for Fic-mediated adenylylation in mammalian signaling.     

Expression of a bacterial 3‐dehydroshikimate dehydratase reduces lignin content and improves biomass saccharification efficiency

Lignin confers recalcitrance to plant biomass used as feedstocks in agro‐processing industries or as source of renewable sugars for the production of bioproducts. The metabolic steps for the synthesis of lignin building blocks belong to the shikimate and phenylpropanoid pathways. Genetic engineering efforts to reduce lignin content typically employ gene knockout or gene silencing techniques to constitutively repress one of these metabolic pathways. Recently, new strategies have emerged offering better spatiotemporal control of lignin deposition, including the expression of enzymes that interfere with the normal process for cell wall lignification. In this study, we report that expression of a 3‐dehydroshikimate dehydratase (QsuB from Corynebacterium glutamicum) reduces lignin deposition in Arabidopsis cell walls. QsuB was targeted to the plastids to convert 3‐dehydroshikimate – an intermediate of the shikimate pathway – into protocatechuate. Compared to wild‐type plants, lines expressing QsuB contain higher amounts of protocatechuate, p‐coumarate, p‐coumaraldehyde and p‐coumaryl alcohol, and lower amounts of coniferaldehyde, coniferyl alcohol, sinapaldehyde and sinapyl alcohol. 2D‐NMR spectroscopy and pyrolysis‐gas chromatography/mass spectrometry (pyro‐GC/MS) reveal an increase of p‐hydroxyphenyl units and a reduction of guaiacyl units in the lignin of QsuB lines. Size‐exclusion chromatography indicates a lower degree of lignin polymerization in the transgenic lines. Therefore, our data show that the expression of QsuB primarily affects the lignin biosynthetic pathway. Finally, biomass from these lines exhibits more than a twofold improvement in saccharification efficiency. We conclude that the expression of QsuB in plants, in combination with specific promoters, is a promising gain‐of‐function strategy for spatiotemporal reduction of lignin in plant biomass.     

Arsenic, cadmium and neuron specific enolase (ENO2, γ-enolase) expression in breast cancer

Background

Neuron specific enolase (ENO2, γ-enolase) has been used as a biomarker to help identify neuroendocrine differentiation in breast cancer. The goal of the present study was to determine if ENO2 expression in the breast epithelial cell is influenced by the environmental pollutants, arsenite and cadmium. Acute and chronic exposure of MCF-10A cells to As⁺³ and Cd⁺² sufficient to allow colony formation in soft agar, was used to determine if ENO2 expression was altered by these pollutants.

Results

It was shown that both As⁺³ and Cd⁺² exposure caused significant increases in ENO2 expression under conditions of both acute and chronic exposure. In contrast, ENO1, the major glycolytic enolase in non-muscle and neuronal cells, was largely unaffected by exposure to either As⁺³ or Cd⁺². Localization studies showed that ENO2 in the MCF-10A cells transformed by As⁺³ or Cd⁺² had both a cytoplasmic and nuclear localization. In contrast, ENO1 was localized to the cytoplasm. ENO2 localized to the cytoplasm was found to co-localized with ENO1.

Conclusion

The results are the first to show that ENO2 expression in breast epithelial cells is induced by acute and chronic exposure to As⁺³ or Cd⁺². The findings also suggest a possible link between As⁺³ and Cd⁺² exposure and neuroendocrine differentiation in tumors. Overall, the results suggest that ENO2 might be developed as a biomarker indicating acute and/or chronic environmental exposure of the breast epithelial cell to As⁺³ and Cd⁺².     

Incorporating population-level variation in thermal performance into predictions of geographic range shifts

Determining how species' geographic ranges are governed by current climates and how they will respond to rapid climatic change poses a major biological challenge. Geographic ranges are often spatially fragmented and composed of genetically differentiated populations that are locally adapted to different thermal regimes. Tradeoffs between different aspects of thermal performance, such as between tolerance to high temperature and tolerance to low temperature or between maximal performance and breadth of performance, suggest that the performance of a given population will be a subset of that of the species. Therefore, species-level projections of distribution might overestimate the species' ability to persist at any given location. However, current approaches to modeling distributions often do not consider variation among populations. Here, we estimated genetically-based differences in thermal performance curves for growth among 12 populations of the scarlet monkeyflower, Mimulus cardinalis, a perennial herb of western North America. We inferred the maximum relative growth rate (RGR(max)), temperature optimum (T(opt)), and temperature breadth (T(breadth)) for each population. We used these data to test for tradeoffs in thermal performance, generate mechanistic population-level projections of distribution under current and future climates, and examine how variation in aspects of thermal performance influences forecasts of range shifts. Populations differed significantly in RGR(max) and had variable, but overlapping, estimates of T(opt) and T(breadth). T(opt) declined with latitude and increased with temperature of origin, consistent with tradeoffs between performances at low temperatures versus those at high temperatures. Further, T(breadth) was negatively related to RGR(max), as expected for a specialist-generalist tradeoff. Parameters of the thermal performance curve influenced properties of projected distributions. For both current and future climates, T(opt) was negatively related to latitudinal position, while T(breadth) was positively related to projected range size. The magnitude and direction of range shifts also varied with T(opt) and T(breadth), but sometimes in unexpected ways. For example, the fraction of habitat remaining suitable increased with T(opt) but decreased with T(breadth). Northern limits of all populations were projected to shift north, but the magnitude of shift decreased with T(opt) and increased with T(breadth). Median latitude was projected to shift north for populations with high T(breadth) and low T(opt), but south for populations with low T(breadth) and high T(opt). Distributions inferred by integrating population-level projections did not differ from a species-level projection that ignored variation among populations. However, the species-level approach masked the potential array of divergent responses by populations that might lead to genotypic sorting within the species' range. Thermal performance tradeoffs among populations within the species' range had important, but sometimes counterintuitive, effects on projected responses to climatic change.     

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.