A 5-Enolpyruvylshikimate 3-Phosphate Synthase Functions as a Transcriptional Repressor in Populus.

Long-lived perennial plants, with distinctive habits of inter-annual growth, defense, and physiology, are of great economic and ecological importance. However, some biological mechanisms resulting from genome duplication and functional divergence of genes in these systems remain poorly studied. Here, we discovered an association between a poplar (Populus trichocarpa) 5-enolpyruvylshikimate 3-phosphate synthase gene (PtrEPSP) and lignin biosynthesis. Functional characterization of PtrEPSP revealed that this isoform possesses a helix-turn-helix motif in the N terminus and can function as a transcriptional repressor that regulates expression of genes in the phenylpropanoid pathway in addition to performing its canonical biosynthesis function in the shikimate pathway. We demonstrated that this isoform can localize in the nucleus and specifically binds to the promoter and represses the expression of a SLEEPER-like transcriptional regulator, which itself specifically binds to the promoter and represses the expression of PtrMYB021 (known as MYB46 in Arabidopsis thaliana), a master regulator of the phenylpropanoid pathway and lignin biosynthesis. Analyses of overexpression and RNAi lines targeting PtrEPSP confirmed the predicted changes in PtrMYB021 expression patterns. These results demonstrate that PtrEPSP in its regulatory form and PtrhAT form a transcriptional hierarchy regulating phenylpropanoid pathway and lignin biosynthesis in Populus.

Transgenic switchgrass (Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: a 2-year comparative analysis of field-grown lines modified for target gene or genetic element expression.

Transgenic Panicum virgatum L. silencing (KD) or overexpressing (OE) specific genes or a small RNA (GAUT4-KD, miRNA156-OE, MYB4-OE, COMT-KD and FPGS-KD) was grown in the field and aerial tissue analysed for biofuel production traits. Clones representing independent transgenic lines were established and senesced tissue was sampled after year 1 and 2 growth cycles. Biomass was analysed for wall sugars, recalcitrance to enzymatic digestibility and biofuel production using separate hydrolysis and fermentation. No correlation was found between plant carbohydrate content and biofuel production pointing to overriding structural and compositional elements that influence recalcitrance. Biomass yields were greater for all lines in the second year as plants establish in the field and standard amounts of biomass analysed from each line had more glucan, xylan and less ethanol (g/g basis) in the second- versus the first-year samples, pointing to a broad increase in tissue recalcitrance after regrowth from the perennial root. However, biomass from second-year growth of transgenics targeted for wall modification, GAUT4-KD, MYB4-OE, COMT-KD and FPGS-KD, had increased carbohydrate and ethanol yields (up to 12% and 21%, respectively) compared with control samples. The parental plant lines were found to have a significant impact on recalcitrance which can be exploited in future strategies. This summarizes progress towards generating next-generation bio-feedstocks with improved properties for microbial and enzymatic deconstruction, while providing a comprehensive quantitative analysis for the bioconversion of multiple plant lines in five transgenic strategies.

Association of DDT and heptachlor epoxide in human blood with diabetic nephropathy.

Six organochlorine pesticides and pesticide metabolites in human blood were tested to determine their relationships with diabetic nephropathy. The data were derived from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 (unweighted, n=2992, population estimate=133,088,752). The six chemicals were p,p'-DDT (dichlorodiphenyltrichloroethane), p,p'-DDE (dichlorodiphenyltrichloroethylene), beta-hexachlorocyclohexane, oxychlordane, trans-nonachlor and heptachlor epoxide. In this research, total diabetes included diagnosed and undiagnosed diabetes (glycohemoglobin, A1c ≥6.5%), and nephropathy was defined as a urinary albumin to creatinine ratio >30 mg/g, representing microalbuminuria and macroalbuminuria. The pesticide p,p'-DDT and pesticide metabolite heptachlor epoxide were significantly associated with total diabetes with nephropathy, with odds ratios of 2.08 (95% CI 1.06-4.11) and 1.75 (95% CI 1.05-2.93), respectively. Organochlorine pesticides are thought to act through the constitutive androstane receptor/pregnane X receptor disease pathway, but this is not well established. When p,p'-DDT and heptachlor epoxide were both elevated, the odds ratio for diabetic nephropathy was 2.76 (95% CI 1.31-5.81), and when six of six organochlorine pesticides and pesticide metabolites, were elevated, the odds ratio for diabetic nephropathy was 3.00 (95% CI 1.08-8.36). The differences in the odds ratios for these groups appear to be due to differences in the mean heptachlor epoxide concentration of each category. Organochlorine pesticides and pesticide metabolites are known to have estrogenic, antiestrogenic or antiandrogenic activity. The constitutive androstane receptor/pregnane X receptor pathway is thought to interact with the aryl hydrocarbon receptor pathway, and the associations noted may be due to that interaction.

Dioxins, furans and dioxin-like PCBs in human blood: causes or consequences of diabetic nephropathy?

Nephropathy, or kidney disease, is a major, potential complication of diabetes. We assessed the association of 6 chlorinated dibenzo-p-dioxins, 9 chlorinated dibenzofurans and 8 polychlorinated biphenyls (PCBs) in blood with diabetic nephropathy in the 1999-2004 National Health and Nutrition Examination Survey (unweighted N=2588, population estimate=117,658,357). Diabetes was defined as diagnosed or undiagnosed (glycohemoglobin ≥ 6.5%) and nephropathy defined as urinary albumin to creatinine ratio >30 mg/g, representing microalbuminuria or macroalbuminuria. For the 8 chemicals analyzed separately, values above the 75th percentile were considered elevated, whereas for the other 15 compounds values above the maximum limit of detection were considered elevated. Seven of 8 dioxins and dioxin-like compounds, analyzed separately, were found to be associated with diabetic nephropathy. The chemicals associated with diabetic nephropathy were: 1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin; 2,3,4,7,8-Pentachlorodibenzofuran; PCB 126; PCB 169; PCB 118; and PCB 156. Three of the 8 dioxins and dioxin-like compounds; 1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin; 2,3,4,7,8-Pentachlorodibenzofuran and PCB 118; expressed as log-transformed continuous variables; were associated with diabetes without nephropathy. When 4 or more of the 23 chemicals were elevated the odds ratios were 7.00 (95% CI=1.80-27.20) for diabetic nephropathy and 2.13 (95% CI=0.95-4.78) for diabetes without nephropathy. Log-transformed toxic equivalency (TEQ) was associated with both diabetic nephropathy, and diabetes without nephropathy, the odds ratios were 2.35 (95% CI=1.57-3.52) for diabetic nephropathy, and 1.44 (95% CI=1.11-1.87) for diabetes without nephropathy. As the kidneys function to remove waste products from the blood, diabetic nephropathy could be either the cause or the consequence (or both) of exposure to dioxins, furans and dioxin-like PCBs.

Associations of dioxins, furans and dioxin-like PCBs with diabetes and pre-diabetes: is the toxic equivalency approach useful?

Toxic equivalency factors for dioxins and dioxin-like compounds have been established by the World Health Organization. Toxic equivalency (TEQ) was derived using 6 chlorinated dibenzo-p-dioxins, 9 chlorinated dibenzofurans and 8 polychlorinated biphenyls, in blood, from the 1999-2004 National Health and Nutrition Examination Survey. Relationships of 8 individual chemicals, the number of compounds elevated, and TEQ with pre-diabetes and total diabetes (diagnosed and undiagnosed) were investigated using logistic regressions. For the 8 chemicals analyzed separately, values above the 75th percentile were considered elevated, whereas for the other 15 compounds, values above the maximum limit of detection were considered elevated. Pre-diabetes with glycohemoglobin (A1c) 5.9-6.4% was associated with PCB 126, PCB 118 and having one or more compounds elevated (odds ratio 2.47, 95% CI 1.51-4.06). Pre-diabetes with A1c 5.7-5.8% was not associated with any individual chemical or the number of compounds elevated. Total diabetes was associated with 6 of the 8 individual compounds tested, and was associated with having 4 or more compounds elevated. Toxic equivalency ≥81.58 TEQ fg/g was associated with total diabetes (odds ratio 3.08, 95% CI 1.20-7.90), but was not associated with A1c 5.9-6.4%. Having multiple compounds elevated appeared to be important for total diabetes, whereas for pre-diabetes with A1c 5.9-6.4%, having a single compound elevated appeared most important. Diabetes plus A1c ≥5.9% was associated with 34.16-81.57 TEQ fg/g (odds ratio 2.00, 95% CI 1.06-3.77) and with ≥81.58 TEQ fg/g (odds ratio 2.48, 95% CI 1.21-5.11), indicating that half the population has elevated risk for this combination of conditions.

Mocs1 (Molybdenum cofactor synthesis 1) may contribute to lifespan extension in Drosophila.

While evaluating the effect on lifespan of decreased ribosomal protein (Rp) expression in Drosophila, we discovered a potential function in the same process for the Molybdenum cofactor synthesis 1 (Mocs1) gene. We utilized the UAS-GAL4 inducible system, by crossing tissue-specific GAL4 drivers to the Harvard Drosophila Transgenic RNAi Project (TrIP) responder lines for Rp gene knockdown. We also employed a negative control that knocked down a gene unrelated to Drosophila (GAL4). Relative to the genetic background in which no driven transgenes were present, lifespan was significantly lengthened in females, both for Rp knockdown and the negative GAL4 control. We reasoned that the Mocs1 gene, located immediately downstream of the integration site on the third chromosome where all the TrIP responders are targeted might be responsible for the lifespan effects observed, due to the potential for upregulation using the UAS-GAL4 system. We repeated the lifespan experiment using an enhancer trap in the same location as the TrIP transgenes, and found that lifespan was significantly lengthened in females that possessed both the driver and responder, relative to controls, implicating Mocs1 in the biology of aging.

The meaning of 'fruits' and 'vegetables'.

OBJECTIVE: Fruit and vegetable consumption is a focus of research and nutrition education; yet, there is no universal agreement on the meaning of 'fruits' and 'vegetables'. Our objective was to describe survey respondent perceptions about a set of foods with regard to whether the food is a fruit, vegetable or something else. DESIGN: Three cross-sectional studies. SETTING: Two small studies involving cognitive interviewing sessions; and one large self-administered population survey. SUBJECTS: US adults in two small studies (n 55 and 80) and one large survey (n 3312), all with multiple race/ethnicities. RESULTS: Perceptions varied. In the survey, rice was considered a vegetable by about 20 % of respondents. In one small study, Spanish speakers were more likely to consider rice a vegetable, and Chinese speakers less likely, than were English speakers. Black beans were frequently classified as something other than vegetable or fruit. Among Hispanics, Spanish speakers were less likely than English speakers to consider beans a vegetable. Overall, tomatoes were classified as both fruit and vegetable, and these perceptions varied by race/ethnicity. CONCLUSIONS: Substantial disagreement among the fruit, vegetable and other food domains highlights the importance of clearly defining the desired constructs. Foods that require specific instruction include rice, dried beans, potatoes, tomatoes and fruits and vegetables in mixtures and condiments. For measurement, additional questions or explanations may be needed to clarify which foods are of interest. For communication, the global message to increase consumption of fruit and vegetables should be reinforced with specific guidance.

Knowledge of and adherence to fruit and vegetable recommendations and intakes: results of the 2003 health information national trends survey.

Attention to cancer-relevant communication (e.g., fruit/vegetable intake recommendations) through various media has been shown to be a pivotal step in reduction of the cancer burden, thus underscoring the importance of examining associations between exposure to health media and knowledge of and adherence to fruit/vegetable intake recommendations. The purpose of the present study was to assess factors associated with fruit/vegetable intake knowledge and behavior. The authors analyzed data collected from the 2003 Health Information National Trends Survey to evaluate the effect of fruit/vegetable intake knowledge on behavior, and the relationship of this effect with biobehavioral, sociodemographic, and communication characteristics. Participants who were knowledgeable of fruit/vegetable intake recommendations and consumed at least 5 fruit/vegetable servings per day were classified as informed compliers. Associations were observed for being an informed complier and paying "a lot" of attention to health media on the radio, in the newspaper, and in magazines and "a little" or "some" attention to health media in magazines or on the Internet. The recent explosion of available cancer-related information through various media underscores the importance of examining associations between exposure to health media and knowledge of and adherence to fruit/vegetable intake recommendations.

Improving fruit and vegetable consumption: use of farm-to-consumer venues among US adults.

Improvements to the food environment including new store development and more farm-to-consumer approaches (ie, farmers' markets, roadside stands, pick-your-own produce farms, or community-supported agriculture programs) may aid Americans in making healthier dietary choices. We analyzed data from a subset of respondents (N = 1,994) in the National Cancer Institute's Food Attitudes and Behaviors Survey, a mail survey of US adults. We determined associations between primary grocery shoppers' region and sociodemographic characteristics and frequency of purchasing fruits and vegetables in the summer from farm-to-consumer venues. A little more than one-quarter (27%) of grocery shoppers reported a frequency of at least weekly use of farm-to-consumer approaches. Older adults and respondents who live in the Northeast were most likely to shop farm-to-consumer venues at least weekly, and no differences were found by sex, race/ethnicity, education, or annual household income. These findings suggest that farm-to-consumer venues are used by many Americans and could be expanded to increase access to fruits and vegetables.

Developing a fuzzy logic-based risk assessment for groundwater contamination from well integrity failure during hydraulic fracturing.

Recent natural gas development by means of hydraulic fracturing requires a detailed risk analysis to eliminate or mitigate damage to the natural environment. Such geo-energy related subsurface activities involve complex engineering processes and uncertain data, making comprehensive, quantitative risk assessments a challenge to develop. This research seeks to develop a risk framework utilising data for quantitative numerical analysis and expert knowledge for qualitative analysis in the form of fuzzy logic, focusing on hydraulically fractured wells during the well stimulation stage applied to scenarios in the UK and Canada. New fault trees are developed for assessing cement failure in the vertical and horizontal directions, resulting in probabilities of failure of 3.42% and 0.84%, respectively. An overall probability of migration to groundwater during the well injection stage was determined as 0.0006%, compared with a Canadian case study which considered 0.13% of wells failed during any stage of the wells life cycle. It incorporates various data types to represent the complexity of hydraulic fracturing, encouraging a more complete and accurate analysis of risk failures which engineers can directly apply to old and new hydraulic fracturing sites without the necessity for extensive historic and probabilistic data. This framework can be extended to assess risk across all stages of well development, which would lead to a gap in the modelled and actual probabilities narrowing. The framework developed has relevance to other geo-energy related subsurface activities such as CO2 sequestration, geothermal, and waste fluid injection disposal.

Sugar release and growth of biofuel crops are improved by downregulation of pectin biosynthesis.

Cell walls in crops and trees have been engineered for production of biofuels and commodity chemicals, but engineered varieties often fail multi-year field trials and are not commercialized. We engineered reduced expression of a pectin biosynthesis gene (Galacturonosyltransferase 4, GAUT4) in switchgrass and poplar, and find that this improves biomass yields and sugar release from biomass processing. Both traits were maintained in a 3-year field trial of GAUT4-knockdown switchgrass, with up to sevenfold increased saccharification and ethanol production and sixfold increased biomass yield compared with control plants. We show that GAUT4 is an α-1,4-galacturonosyltransferase that synthesizes homogalacturonan (HG). Downregulation of GAUT4 reduces HG and rhamnogalacturonan II (RGII), reduces wall calcium and boron, and increases extractability of cell wall sugars. Decreased recalcitrance in biomass processing and increased growth are likely due to reduced HG and RGII cross-linking in the cell wall.

Erratum: The impact of host sex on the outcome of co-infection.

A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.

Exposure to DDT and diabetic nephropathy among Mexican Americans in the 1999-2004 National Health and Nutrition Examination Survey.

Concentrations of the pesticide DDT (dichlorodiphenyltrichloroethane) and its metabolite DDE (dichlorodiphenyldichloroethylene), in the blood of Mexican Americans, were evaluated to determine their relationships with diabetes and diabetic nephropathy. The data were derived from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 (unweighted N = 1,411, population estimate = 13,760,609). The sample included teens, 12-19 years old, which accounted for 19.8% of the data. The time of the study overlapped the banning of DDT in Mexico in the year 2000, and those participants born in Mexico were exposed to DDT before they immigrated to the US. We sought to better understand the relationship of DDT with diabetes in a race/ethnicity group prone to develop diabetes and exposed to DDT. In this study, nephropathy was defined as urinary albumin to creatinine ratio >30 mg/g, representing microalbuminuria and macroalbuminuria, and total diabetes was defined as diagnosed and undiagnosed diabetes (glycohemoglobin, A1c ≥ 6.5%). The proportion with the isomer p,p'-DDT >0.086 ng/g (above the maximum limit of detection) was 13.3% for Mexican Americans born in the US, and 36.9% for those born in Mexico. Levels of p,p'-DDT >0.086 ng/g were associated with total diabetes with nephropathy (odds ratio = 4.42, 95% CI 2.23-8.76), and with total diabetes without nephropathy (odds ratio = 2.02, 95% CI 1.19-3.44). The third quartile of p,p'-DDE (2.99-7.67 ng/g) and the fourth quartile of p,p'-DDE (≥7.68 ng/g) were associated with diabetic nephropathy and had odds ratios of 5.32 (95% CI 1.05-26.87) and 14.95 (95% CI 2.96-75.48) compared to less than the median, respectively, whereas p,p'-DDE was not associated with total diabetes without nephropathy. The findings of this study differ from those of a prior investigation of the general adult US population in that there were more associations found with the Mexican Americans sample.

The impact of host sex on the outcome of co-infection.

Males and females vary in many characteristics that typically underlie how well a host is able to fight infection, such as body-size, immune capacity, or energy availability. Although well studied in the context of sexual signalling, there is now growing recognition that these differences can influence aspects of pathogen evolution as well. Here we consider how co-infection between multiple pathogen strains is shaped by male-female differences. In natural populations, infections by more than one pathogen strain or species are believed to be a widespread occurrence. Using the water flea, Daphnia magna, we exposed genetically identical males and females to replicated bacterial co-infections. We found that pathogen transmission and virulence were much higher in females. However, males did not simply lower average pathogen fitness, but rather the influence of co-infection was more varied and less defined than in females. We discuss how pathogens may have more fitness benefits to gain, and consequently to lose, when infecting one sex over the other.

Association of dioxins, furans and dioxin-like PCBs in human blood with nephropathy among US teens and young adults.

We assessed the association of three chlorinated dibenzo-p-dioxins, a chlorinated dibenzofuran, and four dioxin-like polychlorinated biphenyls (PCBs) in human blood with nephropathy (microalbuminuria or macroalbuminuria) among teens and young adults (12-30 years old) having normal glycohemoglobin (A1c <5.7%). The data were derived from the 1999-2004 National Health and Nutrition Examination Survey (unweighted n=1504, population estimate=38,806,338). In this paper, nephropathy refers to normal A1c with nephropathy. In an all-adult sample (Everett CJ, Thompson OM. Dioxins, furans and dioxin-like PCBs in human blood: causes or consequences of diabetic nephropathy? Environ Res 2014;132:126-31), the cut-offs for these chemicals being considered elevated, were defined as the 75th percentile. Using these same cut-offs again, the proportion of those with one or more of the eight dioxin-like compounds elevated was 9.9%. The four chemicals associated with nephropathy were 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin, PCB 126, PCB 169, and PCB 156. The proportion with one or more of these four dioxin-like chemicals elevated was 3.9% (unweighted n=46) and the odds ratio (OR) for nephropathy was 7.1 [95% confidence interval (CI) 1.8-28.1]. The association was strong among females (OR 17.4, 95% CI 3.4-88.6), but among males there were no cases of nephropathy when one or more of the four dioxin-like chemicals were elevated, and therefore no association. In a separate analysis, elevated toxic equivalency, defined using the eight dioxin-like chemicals (TEQ8), was associated with nephropathy. TEQ8 ≥50.12 fg/g included 2.6% of the sample (unweighted n=28) and had an OR of 5.8 (95% 1.3-25.9) for nephropathy. As found in the analysis of one or more of four dioxin-like chemicals elevated, TEQ8 ≥50.12 fg/g was associated with nephropathy among females (OR 11.9, 95% CI 1.6-87.2), but not males. Trends for least-squares means also differed by gender, but there were no significant differences in mean TEQ8 between normal subjects and those having nephropathy in either males or females. We also evaluated pre-diabetes (A1c 5.7-6.4%) without nephropathy and found no associations when one or more of four dioxin-like compounds were elevated, or when TEQ8 was ≥50.12 fg/g. In this study, associations of dioxin-like chemicals with nephropathy were found among females at an early age. Prospective studies are needed to determine if dioxin-like compounds cause nephropathy, or if these relationships are cases of reverse causation.

Phenotypic characterization and comparative transcriptomics of evolved Saccharomyces cerevisiae strains with improved tolerance to lignocellulosic derived inhibitors.

BACKGROUND: Lignocellulosic biomass continues to be investigated as a viable source for bioethanol production. However, the pretreatment process generates inhibitory compounds that impair the growth and fermentation performance of microorganisms such as Saccharomyces cerevisiae. Pinewood specifically has been shown to be challenging in obtaining industrially relevant ethanol titers. An industrial S. cerevisiae strain was subjected to directed evolution and adaptation in pretreated pine biomass and resultant strains, GHP1 and GHP4, exhibited improved growth and fermentative ability on pretreated pine in the presence of related inhibitory compounds. A comparative transcriptomic approach was applied to identify and characterize differences in phenotypic stability of evolved strains. RESULTS: Evolved strains displayed different fermentative capabilities with pretreated pine that appear to be influenced by the addition or absence of 13 inhibitory compounds during pre-culturing. GHP4 performance was consistent independent of culturing conditions, while GHP1 performance was dependent on culturing with inhibitors. Comparative transcriptomics revealed 52 genes potentially associated with stress responses to multiple inhibitors simultaneously. Fluorescence microscopy revealed improved cellular integrity of both strains with mitochondria exhibiting resistance to the damaging effects of inhibitors in contrast to the parent. CONCLUSIONS: Multiple potentially novel genetic targets have been discovered for understanding stress tolerance through the characterization of our evolved strains. This study specifically examines the synergistic effects of multiple inhibitors and identified targets will guide future studies in remediating effects of inhibitors and further development of robust yeast strains for multiple industrial applications.

Development of Agave as a dedicated biomass source: production of biofuels from whole plants.

BACKGROUND: Agave species can grow well in semi-arid marginal agricultural lands around the world. Selected Agave species are used largely for alcoholic beverage production in Mexico. There are expanding research efforts to use the plentiful residues (bagasse) for ethanol production as the beverage manufacturing process only uses the juice from the central core of mature plants. Here, we investigate the potential of over a dozen Agave species, including three from cold semi-arid regions of the United States, to produce biofuels using the whole plant. RESULTS: Ethanol was readily produced by Saccharomyces cerevisiae from hydrolysate of ten whole Agaves with the use of a proper blend of biomass degrading enzymes including inulinase that overcomes inhibition of most of the species tested. As an example, US grown Agave neomexicana produced 119 ± 11 mg ethanol/g biomass. Unlike yeast fermentations, Clostridium beijerinckii produced n-butanol plus acetone from all species tested. Butyric acid, a precursor of n-butanol, was also present due to incomplete conversion during the screening process. Since Agave contains high levels of free and polyfructose which are readily destroyed by acidic pretreatment, a two-step procedure was developed to depolymerize polyfructose while maintaining its fermentability. The hydrolysate from before and after dilute acid processing was used in C. beijerinckii fermentations with selected Agave species with A. neomexicana producing 144 ± 4 mg fermentation products/g biomass. CONCLUSIONS: Results showed Agave's potential to be a source of fermentable sugars beyond the existing beverage species to now include many species previously unfermentable by yeast, including cold-tolerant lines. This development should stimulate development of Agave as a dedicated feedstock for biofuels in semi-arid regions throughout the globe.

Consolidated bioprocessing of transgenic switchgrass by an engineered and evolved Clostridium thermocellum strain.

BACKGROUND: Switchgrass is an abundant and dedicated bioenergy feedstock, however its inherent recalcitrance is one of the economic hurdles for producing biofuels. The downregulation of the caffeic acid O-methyl transferase (COMT) gene in the lignin pathway of switchgrass reduced lignin content and S/G ratio, and the transgenic lines showed improved fermentation yield with Saccharomyces cerevisiae and wild-type Clostridium thermocellum (ATCC 27405) in comparison to the wild-type switchgrass. RESULTS: Here we examine the conversion and yield of the COMT transgenic and wild-type switchgrass lines with an engineered and evolved C. thermocellum (M1570) strain. The fermentation of the transgenic switchgrass by M1570 had superior conversion relative to the wild-type control switchgrass line with an increase in conversion of approximately 20% and ethanol being the primary product accounting for 90% of the total metabolites measured by HPLC analysis. CONCLUSIONS: The engineered and evolved C. thermocellum M1570 was found to respond to the apparent reduced recalcitrance of the COMT switchgrass with no substrate inhibition, producing more ethanol on the transgenic feedstock than the wild-type substrate. Since ethanol was the main fermentation metabolite produced by an engineered and evolved C. thermocellum strain, its ethanol yield on a transgenic switchgrass substrate (gram/gram (g/g) glucan liberated) is the highest produced thus far. This result indicates that the advantages of a modified feedstock can be combined with a modified consolidated bioprocessing microorganism as anticipated.

Patterns of cell division, cell differentiation and cell elongation in epidermis and cortex of Arabidopsis pedicels in the wild type and in erecta.

Plant organ shape and size are established during growth by a predictable, controlled sequence of cell proliferation, differentiation, and elongation. To understand the regulation and coordination of these processes, we studied the temporal behavior of epidermal and cortex cells in Arabidopsis pedicels and used computational modeling to analyze cell behavior in tissues. Pedicels offer multiple advantages for such a study, as their growth is determinate, mostly one dimensional, and epidermis differentiation is uniform along the proximodistal axis. Three developmental stages were distinguished during pedicel growth: a proliferative stage, a stomata differentiation stage, and a cell elongation stage. Throughout the first two stages pedicel growth is exponential, while during the final stage growth becomes linear and depends on flower fertilization. During the first stage, the average cell cycle duration in the cortex and during symmetric divisions of epidermal cells was constant and cells divided at a fairly specific size. We also examined the mutant of ERECTA, a gene with strong influence on pedicel growth. We demonstrate that during the first two stages of pedicel development ERECTA is important for the rate of cell growth along the proximodistal axis and for cell cycle duration in epidermis and cortex. The second function of ERECTA is to prolong the proliferative phase and inhibit premature cell differentiation in the epidermis. Comparison of epidermis development in the wild type and erecta suggests that differentiation is a synchronized event in which the stomata differentiation and the transition of pavement cells from proliferation to expansion are intimately connected.

Evaluation of three short dietary instruments to assess fruit and vegetable intake: the National Cancer Institute's food attitudes and behaviors survey.

BACKGROUND: Fruit and vegetable (F/V) intake assessment tools that are valid, reliable, brief, and easy to administer and code are vital to the field of public health nutrition. OBJECTIVE: To evaluate three short F/V intake screeners (ie, a 2-item serving tool, a 2-item cup tool, and a 16-item F/V intake screener) among adults using multiple 24-hour dietary recalls (24-hour recalls) as the reference instrument and evaluate test-retest reliability of the screeners across a 2- to 3-week time period. DESIGN: Validity and reliability study. PARTICIPANTS/SETTING: Two hundred forty-four adults for the validity study and 335 adults for test-retest reliability. STATISTICAL ANALYSES PERFORMED: Median values for F/V intakes were calculated for the screeners and 24-hour recalls. The Wilcoxon signed rank test was used to compare screeners with the 24-hour recalls. Deattenuated Pearson correlations were reported for validity and intraclass correlation coefficient used for reliability. RESULTS: The estimated median daily servings/cups of F/V for the 2-item serving screener was lower, for the 2-item cup screener was equivalent for men but higher for women, and for the 16-item F/V intake screener were about the same when compared with 24-hour recall values. The deattenuated correlations comparing the 24-hour recalls with the screeners were positive but weak for the 2-item serving screener, and were positive and moderate in strength for the 2-item cup and 16-item F/V intake screeners. The test-retest intraclass correlation coefficients were all positive and fairly strong for all of the screeners. CONCLUSIONS: Although dietary screeners offer a more cost-effective, less burdensome way to obtain gross estimates to rank individuals with regard to F/V intake, these methods are not recommended for assessing precise intake levels.