bluuebunny/crossref_metadata_2025 huggingface dataset:
Folate Synthesis and Metabolism in Plants and Prospects For Biofortification
Authors: Basset Gilles J. C. , Quinlivan Eoin P. , Gregory Jesse F. , Hanson Andrew D.
Published: July 2010

Folates are essential cofactors for one‐carbon transfer reactions in most living organisms and are required for the biosynthesis of nucleic acids, amino acids, and pantothenate. Unlike plants and microorganisms, humans cannot synthesize folates de novo and must acquire them from the diet, primarily from plant foods. However, lack of folates is the most common vitamin deficiency in the world and has serious health consequences, including increased risk of neural tube defects in infants, cancers, and vascular diseases. Consequently, there is much interest in engineering plants with enhanced folate content (biofortification). In this review, we outline progress in defining the plant folate synthesis pathway and its unique compartmentation and point out sectors of folate metabolism that have yet to be elucidated, including transport and catabolism. We also consider possible strategies to enhance plant folate synthesis and accumulation by metabolic engineering.
Commercialization of Biopharmaceutical and Bioindustrial Proteins from Plants
Authors: Howard John A.
Published: July 2010

Over the past decade many new products have entered the market as the result of biotechnology. In regard to biotechnology tools related to plants, this has mainly been in the form of products that conferred crop improvement traits. The technology developed for crop improvement, however, can be applied to commercialize nonfood products such as those developed by other host systems such as microbial and animal cell culture systems. The first wave of therapeutic proteins is now in clinical trials for both animals and humans. Other nonfood products are now being introduced into the marketplace. This paper examines a few of these representative products to highlight the potential advantages and hurdles that need to be overcome to bring these products to the market. This includes not only the technical barriers but also what is needed for both regulatory and public acceptance.
Nitrogen Uptake and Utilization in Contrasting Nitrogen Efficient Tropical Maize Hybrids
Authors: Worku Mosisa , Bänziger Marianne , Erley Gunda Schulte auf'm , Friesen Dennis , Diallo Alpha O. , Horst Walter J.
Published: July 2010

Maize cultivars with improved grain yields under nitrogen (N) stress are desirable for sub‐Saharan African maize growing environments. This study assesses N uptake, N utilization, and the genotype × environment (G × E) interaction of 16 tropical maize (Zea mays L.) hybrids differing in grain yield under low‐N conditions. Hybrids were evaluated under low‐N, medium‐N, and high‐N at Harare, Zimbabwe, in 2003 and 2004 and at Kiboko, Kenya, in 2003. At maturity, N accumulation in the aboveground biomass ranged from 47 to 278 kg N ha−1 in various experiments. Grain yields ranged from 1.5 to 4.3 Mg ha−1 and 10.6 to 14.9 Mg ha−1 for the same experiments, respectively. Significant G × E interactions were observed which became more pronounced as the difference in N stress intensity between two environments increased. High grain yield under low‐N was consistently associated with higher postanthesis N uptake, increased grain production per unit N accumulated, and an improved N harvest index. Additive main effect and multiplicative interaction analysis identified hybrids with specific adaptation to either low‐N or high‐N environments. Several hybrids produced high yields under both low‐N and high‐N conditions. More detailed studies with these hybrids are required to examine the underlying physiological mechanisms contributing to the N‐use efficiency.
Effects of Abscisic Acid on Antioxidant Systems of Stylosanthes guianensis (Aublet) Sw. under Chilling Stress
Authors: Zhou Biyan , Guo Zhenfei , Liu Zhiling
Published: July 2010

Stylosanthes guianensis (Aublet) Sw. is an important pasture legume in tropical and subtropical countries. Chilling injury of S. guianensis is a serious problem in subtropical cultivated areas. An experiment was conducted under controlled conditions to study the effect of abscisic acid (ABA) on S. guianensis and its relation to antioxidant systems under chilling stress. Stylosanthes guianensis seedlings were sprayed with 10 mg L−1 ABA or water. One day later, the plants were transferred to a 10°C growth chamber and grown for 7 d with a 12‐h photoperiod at 160 μmol m−2 s−1 photosynthetic photon flux density. The chilling treated plants were then rewarmed to 28°C for 2 d. During the 9‐d treatment, a series of enzyme activities, relative water content (RWC), and electrolyte leakage were measured on sampled leaflets. The results showed that chilling increased electrolyte leakage of both water‐ and ABA‐treated plants, while RWC decreased under chilling conditions. ABA‐treated plants had lower electrolyte leakage and higher RWC than those of water‐treated plants. Activities of ascorbate peroxidase (APX) and catalase (CAT) and contents of reduced glutathione (GSH) and ascorbic acid (AsA) were transiently enhanced by ABA treatment before the plants were subject to chilling. ABA‐treated S. guianensis retained higher levels of superoxide dismutase (SOD), APX, GSH, and AsA than water‐treated ones under chilling conditions. The results suggested that ABA‐increased chilling resistance in S. guianensis is partially associated with enhanced scavenging systems.
Assessment of Inter Simple Sequence Repeat Markers to Differentiate Sympatric Wild and Domesticated Populations of Common Bean
Authors: González A. , Wong A. , Delgado‐Salinas A. , Papa R. , Gepts P.
Published: July 2010

Efficient assessment of genetic diversity is important for conservation and utilization of genetic resources. We sought to assess the ability of inter simple sequence repeats (ISSRs) as molecular markers to identify genetic diversity both within and among sympatric populations of common bean, Phaseolus vulgaris L. One wild and four domesticated populations originating from the Sierra Norte de Puebla, Mexico, were chosen because they were growing in the same region or field. The ISSR diversity was assessed using four primers that revealed a higher number of strong, polymorphic bands in preliminary analyses. Fifty of these bands could be mapped onto the core linkage map in population BAT93 × Jalo EEP558, whereas four were unlinked. The mapped bands were distributed over nine of the 11 linkage groups, suggesting that they were broadly distributed in the genome. On the basis of a sample of 50 intense bands in these five populations, ISSRs were able to clearly distinguish all populations. Most of the variation was distributed among populations rather than within populations, consistent with the predominantly selfing nature of the species. Differentiation among domesticated populations was much higher (FST ≈ 0.49–0.85) than between the wild and domesticated gene pools (FST = 0.05). Within each population, most loci had achieved near‐fixation. Around 7% of individuals showed a lack of correlation between seed type and ISSR fingerprint. Furthermore, each population contained individuals with unusual markers but present in the other populations (frequency < 5 or 10%). Two nonmutually exclusive explanations were discussed—incomplete lineage sorting and introgression—to account for the presence of these unusual individuals. Overall, ISSR markers were very useful to differentiate closely related populations. Further research is necessary to quantify the actual level of outcrossing.
Contrasting Toxic‐Endophyte Contamination between Endophyte‐Free and Nontoxic‐Endophyte Tall Fescue Pastures
Authors: Barker D. J. , Sulc R. M. , Bultemeier T. L. , McCormick J. S. , Little R. , Penrose C. D. , Samples D.
Published: July 2010

The fungal endophyte Neotyphodium coenophialum Morgan‐Jones and Gams is abundant in tall fescue (Festuca arundinacea Schreb.) and one strategy to alleviate detrimental effects on livestock is to plant endophyte‐free cultivars; however, these pastures frequently become recontaminated by toxic‐endophyte tall fescue. An alternative strategy is to use pastures of tall fescue infected with endophyte that does not produce toxic alkaloids. Our objective was to test the hypothesis that nontoxic‐endophyte infected tall fescue swards (Nontoxic‐E) were more resistant to reinfestation by volunteer tall fescue and its associated toxic endophyte, than endophyte‐free tall fescue swards (E‐). Plots of E‐ and Nontoxic‐E tall fescue (cultivar Jesup) with six levels of contamination by endophyte‐infected K31 (0, 10, 20, 30, 40, 50% of viable seed weight) were established from seed at three sites in Ohio during April 2001. Observed endophyte levels for E‐ at the Jackson site were 77, 118, and 143% greater than expected in autumn 2001, spring 2002, and autumn 2002, respectively. Observed endophyte levels for E‐ at the Belle Valley site were 32, 70, and 39% greater than expected in autumn 2001, spring 2002, and autumn 2002, respectively. Observed endophyte levels for E‐ at the South Charleston site averaged 8% less than expected. Observed endophyte levels in Nontoxic‐E at all sites were consistent with the endophyte levels in the seed that was planted, and plants had a negligible concentration of ergopeptine alkaloids. It was concluded that, where mechanisms for contamination exist, E‐ tall fescue stands can be readily contaminated by volunteer tall fescue and its toxic endophyte; but, Nontoxic‐E tall fescue is less susceptible to contamination by volunteer tall fescue.
Nitrogen Source and Rate Effects on the Production of Buffalograss Forage Grown with Irrigation
Authors: Springer T. L. , Taliaferro C. M. , Hattey J. A.
Published: July 2010

Application of livestock manure to crop lands is one method of recycling nutrients. An experiment was conducted to determine the effect of applying solid cattle (Bos spp.) manure (SCM), liquid swine (Sus spp.) effluent (LSE), or commercial fertilizer (CF; urea) at three application rates (0, 120, or 240 kg N ha−1) on the yield, plant canopy height, and nutritive value (crude protein, CP; and in vitro organic matter digestibility, IVOMD) of buffalograss [Buchloë dactyloides (Nutt.) Engelm.] forage grown with irrigation during a 4‐yr period. Two forage harvests were made in each of four growing seasons, and canopy height was measured before each harvest. For all N sources, seasonal dry matter yield (DMY), canopy height, and CP increased as N rate increased during each of the 3 yr following establishment. However, as the buffalograss stand aged, the yield, canopy height, and nutritive value of forage declined. Given the availability of livestock manure in the High Plains region of the USA and the need to recycle this by‐product from confined animal feeding operations, the application of livestock manure to buffalograss grown with irrigation for hay or pasture could be a viable and sustainable production system. Future work should address the long‐term effects of applying livestock manure to soils in relation to nutrient loading and water quality.
Biomass Yield and Stand Characteristics of Switchgrass in South Central U.S. Environments
Authors: Cassida K. A. , Muir J. P. , Hussey M. A. , Read J. C. , Venuto B. C. , Ocumpaugh W. R.
Published: July 2010

Optimizing feedstock production from switchgrass (Panicum virgatum L.) requires careful matching of genotype to environment, especially for southern U.S. regions. Nine genotypes from four combinations of ecotype and morphological type were harvested once yearly in autumn for 3 or 4 yr at five locations across Texas, Arkansas, and Louisiana that varied in latitude and precipitation. Genotypes were evaluated for dry matter yield (DMY), plant density, tiller density, lodging, and rust (caused by Puccinia spp.) infection. Genotype × environment (G×E) interactions were identified for most traits. Biomass yield of all genotypes tended to increase with latitude, but lowland morphological types may have been more sensitive than upland morphological types to differences in moisture availability. Yield (5.82 vs. 14.97 Mg ha−1, respectively) and persistence (final stand density, 3.99 vs. 5.96 plants m−2) were lower for upland than for lowland genotypes, particularly at higher rainfall and more southern sites. Lowland genotypes were often able to compensate for stand thinning by increasing individual plant size, but upland genotypes were not. Lodging and rust scores were higher for upland than for lowland genotypes. Yield (13.65 vs. 9.75 Mg ha−1) and final plant density (5.58 vs. 4.95 plants m−2) were higher for southern than northern ecotypes. The southern‐lowland combination exhibited the best yield and persistence over the study region, and genotypes within this group exhibited variability in yield among sites. Therefore, development of switchgrass cultivars for biomass production in the southern USA should focus on the southern‐lowland genotypes.
Determination of Ergot Alkaloid Content in Tall Fescue by Near‐Infrared Spectroscopy
Authors: Roberts C. A. , Benedict H. R. , Hill N. S. , Kallenbach R. L. , Rottinghaus G. E.
Published: July 2010

Ergot alkaloids are a class of toxic compounds, some of which are produced by a fungal endophyte in tall fescue (Festuca arundinacea Schreb.). The objective of this research was to measure total ergot alkaloid content in tall fescue by near‐infrared (NIR) spectroscopy with a calibration developed from immunochemical reference data. Eighty‐four tall fescue samples were collected from experiments at the University of Missouri. Samples were from plants that varied in maturity, endophyte status, genotype, growing environment, and storage and preservation treatment. Samples were scanned by NIR radiation and analyzed chemically for ergot alkaloid content using a commercial immunoassay. An empirical prediction equation was developed by regressing NIR reflectance data against absorbance data from the immunoassay. The initial calibrations achieved a 1 − variance ratio (VR) of 0.86 with a mean and standard error of cross validation (SECV) of 0.606 ± 0.12; however, this was possible only when stockpiled tall fescue samples were omitted from the population. Stockpiled samples were checked for chemical accuracy and spectral similarity to the population, and another set of calibrations was developed. The final calibration, which omitted only those stockpiled samples that were infected with a toxic endophyte, had a 1 − VR of 0.89, with a mean and SECV of 0.682 ± 0.11. We concluded that total ergot alkaloid content in tall fescue can be quantified by NIR spectroscopy with a calibration developed from immunochemcial data, though it may not be possible to include samples of stockpiled tall fescue if they are infected with a toxic endophyte. Such a calibration can be robust and precise, reliably predicting an entire class of compounds in a diverse population of tall fescue samples.
Comparison of Transcript Profiles in Wild‐Type and o2 Maize Endosperm in Different Genetic Backgrounds
Authors: Jia Hongwu , Nettleton Dan , Peterson Joan M. , Vazquez‐Carrillo Gricelda , Jannink Jean‐Luc , Scott M. Paul
Published: July 2010

Mutations in the Opaque2 (O2) gene of maize (Zea mays L.) improve the nutritional value of maize by reducing the level of zeins in the kernel. The phenotype of o2 grain is controlled by many modifier genes and is therefore strongly dependent on genetic background. We propose two hypotheses to explain differences in phenotypic severity in different genetic backgrounds: (i) Specific genes are differentially (o2 vs. wild‐type) expressed only in certain genotypes, and (ii) A set of genes are differentially expressed in all backgrounds, but the degree of differential expression differs in different backgrounds. To determine the extent to which these two hypotheses contribute to determining the severity of o2 in different genetic backgrounds, we identified transcripts likely to be differentially expressed in several genetic backgrounds by transcript profile comparison of endosperm RNA pools from eight o2 inbred lines and their wild‐type counterparts. The inbred line B46 was identified as having severe o2 phenotypes while the line M14 was identified as having minimal o2 phenotypes. The degree of wild‐type vs. o2 differential expression of transcripts was determined for these two lines. We found that most genes that are downregulated by o2 tend to be differentially expressed to a greater degree in B46 than in M14, while upregulated genes tend to be more highly differentially expressed in one genetic background or the other. Thus, hypothesis one functions more prominently for upregulated genes while hypothesis two functions most prominently for downregulated genes.
Agronomic Performance of Striga Resistant Early‐Maturing Maize Varieties and Inbred Lines in the Savannas of West and Central Africa
Authors: Badu‐Apraku Baffour , Lum A. Fontem
Published: July 2010

The potential maize (Zea mays L.) yield in the savannas of West and Central Africa (WCA) is constrained by Striga hermonthica (Del.) Benth. parasitism. Field trials at Ferkessedougou, Côte d'Ivoire; Abuja, Nigeria; and Mokwa, Nigeria, in 2002, and at Mokwa and Abuja in 2004, evaluated the performance of 11 early maturing maize varieties under artificial Striga infestation and Striga‐free conditions. Another trial at Mokwa and Abuja in 2004 evaluated 100 early maturing inbred lines under Striga infestation and Striga‐free conditions. The varieties differed significantly in grain yield under both conditions. Acr 94 TZE Comp 5‐W, Acr TZE Comp 5‐Y, and TZE‐W Pop × 1368 STR C1 were identified as promising varieties, based on grain yield, Striga damage ratings, and Striga emergence counts. The most promising variety, Acr 94 TZE Comp. 5‐W in terms of high grain yield, reduced Striga damage and low Striga emergence, outyielded the reference entry by 2% under Striga‐free conditions and 45% under Striga infestation. Ward cluster analysis of the varieties and inbred lines produced four major clusters each, under both Striga‐infested and Striga‐free conditions. In each case, the varieties and inbred lines assigned to each cluster under Striga infestation differed from those in the Striga‐free conditions. Several inbred lines with high grain yield, low Striga emergence and reduced Striga damage were identified as sources of Striga resistance for maize breeding programs in WCA.
Variation between Two Switchgrass Cultivars for Components of Vegetative and Seed Biomass
Authors: Boe Arvid
Published: July 2010

Biomass production potential in switchgrass (Panicum virgatum L.) populations is inversely related to latitude of origin. However, phenological adaptation limits the latitudinal range from which to select populations for breeding for biomass in the northern Great Plains. Objectives of this study were to compare patterns of biomass partitioning, determine importance of tiller density and size, and identify morphological traits as potential selection criteria for two cultivars, Summer (origin 40° 42′ N, 95° 52′ W) and Sunburst (origin 42° 42′ N, 96° 41′ W), of comparable phenology. Summer (12.6 Mg ha−1) produced 20% more vegetative biomass than Sunburst and had higher percent reproductive tillers (62% vs. 40%) and more phytomers tiller−1 (7.9 vs. 6.4). Sunburst had more tillers m−2 (677 vs. 530). Cultivars did not differ for seed biomass (311 kg ha−1), but seeds of Sunburst (1.8 mg seed−1) were 90% heavier than seeds of Summer. Vegetative biomass decreased acropetally among phytomers. Reproductive tillers per m2 and seed mass per panicle were accurate predictors of vegetative and seed biomass, respectively. Frequency of reproductive tillers, number of phytomers per tiller, and rate of phytomer development morphologically differentiated Summer and Sunburst and were potential selection criteria for improving biomass yield within a maturity class of switchgrass adapted to the northern Great Plains.
The Genetic Structure of a Maize Population: The Role of Dominance
Authors: Wardyn Brandon M. , Edwards Jode W. , Lamkey Kendall R.
Published: July 2010

The combined effects of dominance and inbreeding on covariances between relatives are still poorly understood in maize (Zea mays L.) populations. Our objectives were to address the following questions: (i) What is the importance of dominance in a maize synthetic? (ii) How does inbreeding affect the genetic variance among individuals in a maize synthetic. (iii) How do the covariance parameters compare between populations? (iv) How does breeding design impact estimators? We estimated covariance components for inbred relatives in the maize synthetic BSCB1(R)C13. Previous estimates of covariance parameters have been used to explain the ineffectiveness of inbred progeny selection in the stiff‐stalk population BS13. We found that the dominance variance was larger than the additive variance for grain yield, whereas the additive variance was larger than the dominance variance for all other traits. Negative estimates of the covariance between additive and homozygous dominance deviations were found for all traits with the exception of traits associated with reproductive maturity, suggesting a negative relationship between inbred and outbred performance. The correlation between genotypic values and breeding values was lower for grain yield than for any other trait. Our results were similar to previous results found in the stiff‐stalk maize population BS13, suggesting similarity in structure among populations.
Application of Population Genetic Theory and Simulation Models to Efficiently Pyramid Multiple Genes via Marker‐Assisted Selection
Authors: Wang Jiankang , Chapman Scott C. , Bonnett David G. , Rebetzke Greg J. , Crouch Jonathan
Published: July 2010

Breeders face many complex choices in the design of efficient crossing and selection strategies aimed at combining desired alleles into a single target genotype. Both population genetic theory and a breeding simulation tool were used to study the effects of different strategies on population size and number of marker assays required to recover a target genotype in wheat (Triticum aestivum L.). Enriching the frequency of desirable alleles in the F2 of single‐cross and in the F1 of backcross and topcross populations greatly reduced the minimum required population size, but the gain from another enrichment selection is minor. General equations were developed to determine appropriate crossing strategies, and sequential culling was proposed to minimize total marker screening costs. For a topcross of three adapted lines from an existing breeding program, simulation of changes in allele frequencies at nine target genes (seven unlinked) showed that population size was minimized with a three‐stage selection strategy in the F1 generation of the topcross (TCF1), the F2 generation of the topcross (TCF2), and doubled haploid lines (DHs). Enrichment of allelic frequencies in TCF2 reduced the total number of lines screened from >3500 to <600. Eight of the genes were present at frequencies >0.97 after selection, while the tin reduced‐tillering allele was only at 0.77 in the final selected population due to its strong repulsion‐phase linkage to the grain quality gene Glu‐A3 in this cross and the incomplete linkage of the tin marker. Therefore, the presence of the tin gene needs to be further confirmed by other methods.
Effects of Solvent Retention Capacities, Pentosan Content, and Dough Rheological Properties on Sugar Snap Cookie Quality in Chinese Soft Wheat Genotypes
Authors: Zhang Qijun , Zhang Yong , Zhang Yan , He Zhonghu , Peña Roberto J.
Published: July 2010

Development of soft wheat (Triticum aestivum L.) cultivars with excellent cookie quality is an important breeding objective in southern China. Seventeen Chinese soft wheat genotypes grown at three locations in the 2000–2001 and 2001–2002 seasons in the southern winter wheat region, were uniformly evaluated for their solvent retention capacities (SRC), pentosan content, dough rheology, and suitability for making sugar snap cookies, to identify the main parameters that could be used in wheat breeding programs for improving cookie quality. Significantly negative correlations were found between water SRC, sucrose SRC, and sugar snap cookie diameter, and between sodium carbonate SRC, alkaline water retention capacity (AWRC), and water soluble pentosan, while significantly positive correlations were obtained between water, sodium carbonate, lactic acid, and sucrose SRC and AWRC. Alveograph parameters were more closely associated with sugar snap cookie quality compared with parameters from farinograph and extensograph except for water absorption. Water SRC was highly and significantly associated with farinograph water absorption, extensograph extensibility, alveograph P (tenacity), and P/L (the ratio of tenacity and extensibility). Regression analyses showed that sucrose SRC and flour particle size could be used to predict the sugar snap cookie diameter. Cluster analysis based on sugar snap cookie diameter indicated that ‘Jianmai 1’, ‘Wanmai 19’, and ‘Wanmai 48’ were characterized by good cookie quality, with low water soluble and total pentosans, water and particularly sucrose SRC, water absorption, and P and P/L values. It also indicated that substantial progress for soft wheat sugar snap cookie quality improvement could be achieved through appropriate use of current elite germplasm.
Maize Kernel Moisture at Physiological Maturity as Affected by the Source–Sink Relationship during Grain Filling
Authors: Sala Rodrigo G. , Andrade Fernando H. , Westgate Mark E.
Published: July 2010

A wide range of values reported in the literature has precluded the use of grain moisture (GM) as an estimate of physiological maturity (PM) in maize (Zea mays L.). The reason for this variability in GM values remains unclear. Previous evidence suggests that the source–sink ratio could affect the dynamics of kernel water relations during grain filling and thus, GM at PM. To test this possibility, treatments were applied to manipulate the reproductive sink capacity or the assimilate availability during grain filling. Kernel dry weight, water content, and the dry weight to water content (D–W) ratio, were monitored throughout grain filling. A bilinear model relating dry weight and GM was used to estimate GM at PM for each treatment. Severely restricting source capacity during grain filling increased GM at PM. When the source capacity per kernel during grain filling was increased, however, GM at PM was not affected. A single model (r2 = 0.99, p < 0.001) described the relationship between relative dry weight and GM for all hybrids and treatments without source reduction during grain filling. The estimated value of GM at PM for this model was 34.9%. These results suggest that calculating GM late in grain filling can provide a reliable estimate of PM when the source capacity has not been severely restricted. A value of 35% moisture would be adequate in these situations. The D–W ratio of developing kernels was similar across all source–sink treatments until PM. Premature cessation of grain filling caused by defoliation increased the D–W ratio as the kernels continued to desiccate.
Genetic Effects of Thirteen Gossypium barbadense L. Chromosome Substitution Lines in Topcrosses with Upland Cotton Cultivars: II. Fiber Quality Traits
Authors: Jenkins Johnie N. , McCarty Jack C. , Wu Jixiang , Saha Sukumar , Gutierrez Osman , Hayes Russell , Stelly David M.
Published: July 2010

Thirteen chromosome substitution lines (CS‐B) lines with individual 3‐79 Gossypium barbadense L. chromosome or arms substituted into TM‐1, G. hirsutum L., were crossed with five Upland cultivars and additive and dominance effects for fiber micronaire, elongation, length, and strength were measured over four environments. Additive genetic effects were considerably larger than dominance or environmental interaction effects. Fiber strength of 3‐79 and FM966 were 282 and 240 kN m kg−1, respectively. FM966 had greater additive effects for fiber length (1.13 mm) and strength (12.90 kN m kg−1) than any CS‐B line; however, CS‐B25 had the greatest additive effects (8.97 kN m kg−1) for strength among CS‐B lines. The greatest negative additive effect for fiber length was −1.29 mm (CS‐B22sh). Although several CS‐B lines had negative additive effects on strength, none was more negative than TM‐1 (−5.31 kN m kg−1). CS‐B02 and CS‐B25 had additive effects on strength of 2.36 and 8.97 kN m kg−1 SG747 had the greatest negative additive effect (−12.13 kN m kg−1) for strength among cultivars and CS‐B lines. CS‐B07 and CS‐B18 had negative additive effects for fiber strength but had significant and positive dominance effects with FM966. When individual CS‐B lines were crossed with elite cultivars beneficial alleles for fiber properties were uncovered on specific chromosomes or chromosome arms that should aid introgression of alleles from 3‐79 into Upland.
Development of a PCR‐Based Molecular Marker to Select for Nematode Resistance in Peanut
Authors: Chu Y. , Holbrook C. C. , Timper P. , Ozias‐Akins P.
Published: July 2010

The peanut root‐knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] is a significant pathogen on peanut (Arachis hypogaea L.). Nematode resistant cultivars would reduce yield losses while reducing the use of nematicides in fields where these nematodes occur. Through years of breeding effort, nematode resistance gene(s) have been introgressed into peanut cultivars from their wild relatives, Arachis spp. Molecular markers RKN440 and Z3/265, linked to the resistance gene, previously were identified by random amplified polymorphic DNA (RAPD) analysis. Unfortunately, when these markers were applied to our breeding programs, neither could give a reproducible level of correlation with the phenotype data. In this study, we modified the marker RKN440 based on more complete sequencing data and established a new nematode resistance dominant marker 197/909. This marker is reproducible and shows a high correlation with the phenotype data. It amplifies fragments from both susceptible and resistant samples, but of different molecular weights, avoiding false negative judgment caused by failed reactions with dominant markers. When we applied this marker using a cost‐effective, high‐throughput DNA extraction method, it remained a robust assay. Plant breeders will be able to use this new marker to hasten efforts to combine nematode resistance with other important characteristics in peanuts.
Assessment of Different Legumes for the Control of Striga hermonthica in Maize and Sorghum
Authors: Khan Zeyaur R. , Midega Charles A. O. , Hassanali Ahmed , Pickett John A. , Wadhams Lester J.
Published: July 2010

The witchweed, Striga hermonthica (Del.) Benth., is a major constraint to maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench] production in sub‐Saharan Africa. Intercropping maize and sorghum with desmodium (Desmodium spp.) effectively controls Striga and enhances grain yields. Studies were thus conducted to assess the potential role of intercropping maize and sorghum with different food legumes for control of Striga Seasonal Striga counts in the intercrops, other than greenleaf desmodium where the counts consistently remained close to zero, were generally not significantly different from those in the control in both crops. A pooled analysis across seasons, however, showed that intercropping sorghum with cowpea [Vigna unguiculata (L.) Walp.], greengram [Vigna radiata (L.) Wilczek], and crotalaria (Crotalaria ochroleuca G. Don), and maize with crotalaria significantly reduced Striga populations. Within‐season analysis showed that it was only the greenleaf desmodium intercrop that maintained significantly enhanced grain yields relative to the control. On the other hand, multiseason analysis showed that it was only the crotalaria, cowpea, and greenleaf desmodium intercrops in maize and greenleaf desmodium intercrop in sorghum that significantly enhanced grain yields. These results indicate that intercropping sorghum with cowpea, greengram, or crotalaria and maize with crotalaria could be combined with other cultural methods for a sustainable control of S. hermonthica.
Changing the Support of a Spatial Covariate: A Simulation Study
Authors: Hooks Tisha , Pedersen Jeffrey F. , Marx David B. , Gaussoin Roch E.
Published: July 2010

Researchers are increasingly able to capture spatially referenced data on both a response and a covariate more frequently and in more detail. A combination of geostatisical models and analysis of covariance methods may be used to analyze such data. However, very basic questions regarding the effects of using a covariate whose support differs from that of the response variable must be addressed to utilize these methods most efficiently. In this experiment, a simulation study was conducted to assess the following: (i) the gain in efficiency when geostatistical models are used, (ii) the gain in efficiency when analysis of covariance methods are used, and (iii) the effects of including a covariate whose support differs from that of the response variable in the analysis. This study suggests that analyses which both account for spatial structure and exploit information from a covariate are most powerful. Also, the results indicate that the support of the covariate should be as close as possible to the support of the response variable to obtain the most accurate experimental results.
Toward a Reference Sequence of the Soybean Genome: A Multiagency Effort
Authors: Jackson Scott A. , Rokhsar Dan , Stacey Gary , Shoemaker Randy C. , Schmutz Jeremy , Grimwood Jane
Published: July 2010

The face of soybean [Glycine max (L.) Merr.] genetics is set to change with the imminent genome sequence delivered by a triagency group [National Science Foundation (NSF), United States Department of Energy (USDOE), and United States Department of Agriculture (USDA)]. The approaches and alacrity with which scientists will be able to solve biological questions and advance breeding lines will be dramatically enhanced. Questions remain though. How and in what form will the genome be sequenced? How will the genome sequence be linked to genetic and physical maps and how will all this information be accessible for biologists and breeders? In this article, we show how the genome is being sequenced and how various groups and agencies are working together to ensure that the sequence is immediately available and of use to soybean researchers.
A High‐Density Map and PCR Markers for Russian Wheat Aphid Resistance Gene Dn7 on Chromosome 1RS/1BL
Authors: Lapitan Nora L. V. , Peng Junhua , Sharma Vinod
Published: July 2010

The Russian wheat aphid (RWA) [Diuraphis noxia (Kurdjumov)] is an economically significant insect pest of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) in the USA. Since 1986, only one biotype existed in the USA. In 2003, a new biotype appeared which was virulent to all known resistance genes in wheat, with the exception of Dn7. Dn7 is a rye gene transferred into a wheat background via 1RS/1BL translocation. It was previously mapped; however, no PCR‐based markers were developed for marker‐assisted selection (MAS) and the map was sparse. This study presents a higher density map of Dn7 containing 19 markers. The markers spanning Dn7 are XHor2 and Xscb241 at distances of 1.4 and 1 cM, respectively, from Dn7 PCR markers were developed and tested on 19 wheat cultivars. Two markers which amplified rye‐specific fragments proved to be useful for MAS. Xrems1303 amplified a 320‐bp band only in cultivars with high‐level resistance to biotype 2 and is effective for MAS of Dn7. Xib267 is linked to the susceptible locus and amplified a fragment specific for rye Petkus 1RS and would be a good marker for selecting against the susceptible locus. The value of Dn7 as a source of resistance has increased because of the broad spectrum resistance it provides against several biotypes. The markers developed in this study will be useful for facilitating the transfer of Dn7 into wheat cultivars with or without translocation chromosomes containing 1RS.
Scientific Paradigms in Epidemiology and Professional Values
Authors: Steven S.Coughlin
Published: July 2010

A notable feature of the debate about scientific paradigms and theories in epidemiology has been the juxtaposition of scientific, social, and ethical arguments. In some articles on epidemiologic theory and scientific paradigms, ethical issues and professional values have been discussed in order to bolster or clarify the authors' scientific arguments or to point to future directions. However, the introduction of statements laden with social concerns, ethics, and values into a scientific discussion of epidemiologic theory tends to obscure the scientific issues at the heart of the debate. Analyses of professional values and ethics in epidemiology are vitally important, but they should be thorough and well balanced and clearly distinguished as considerations of ethical and social concerns. Judgments about the relative scientific merits of alternative scientific paradigms (or proposed refinements in existing paradigms) should be based upon scientific considerations.
Induction of Human β-Cell Proliferation and Engraftment Using a Single G1/S Regulatory Molecule, cdk6
Authors: Fiaschi-Taesch Nathalie M. , Salim Fatimah , Kleinberger Jeffrey , Troxell Ronnie , Cozar-Castellano Irene , Selk Karen , Cherok Edward , Takane Karen K. , Scott Donald K. , Stewart Andrew F.
Published: July 2010

OBJECTIVE

Most knowledge on human β-cell cycle control derives from immunoblots of whole human islets, mixtures of β-cells and non-β-cells. We explored the presence, subcellular localization, and function of five early G1/S phase molecules—cyclins D1–3 and cdk 4 and 6—in the adult human β-cell.

RESEARCH DESIGN AND METHODS

Immunocytochemistry for the five molecules and their relative abilities to drive human β-cell replication were examined. Human β-cell replication, cell death, and islet function in vivo were studied in the diabetic NOD-SCID mouse.

RESULTS

Human β-cells contain easily detectable cdks 4 and 6 and cyclin D3 but variable cyclin D1. Cyclin D2 was only marginally detectable. All five were principally cytoplasmic, not nuclear. Overexpression of the five, alone or in combination, led to variable increases in human β-cell replication, with the cdk6/cyclin D3 combination being the most robust (15% versus 0.3% in control β-cells). A single molecule, cdk6, proved to be capable of driving human β-cell replication in vitro and enhancing human islet engraftment/proliferation in vivo, superior to normal islets and as effectively as the combination of cdk6 plus a D-cyclin.

CONCLUSIONS

Human β-cells contain abundant cdk4, cdk6, and cyclin D3, but variable amounts of cyclin D1. In contrast to rodent β-cells, they contain little or no detectable cyclin D2. They are primarily cytoplasmic and likely ineffective in basal β-cell replication. Unexpectedly, cyclin D3 and cdk6 overexpression drives human β-cell replication most effectively. Most importantly, a single molecule, cdk6, supports robust human β-cell proliferation and function in vivo.
Effect of Internet Therapeutic Intervention on A1C Levels in Patients With Type 2 Diabetes Treated With Insulin
Authors: Tildesley Hugh D. , Mazanderani Adel B. , Ross Stuart A.
Published: July 2010

OBJECTIVE

To assess the effect of an Internet-based glucose monitoring system (IBGMS) on A1C levels in patients with type 2 diabetes treated with insulin.

RESEARCH DESIGN AND METHODS

This trial involved 50 patients randomly assigned to receive either conventional treatment alone or with additional follow-up through an IBGMS for 6 months. Patients randomized to the intervention group uploaded blood glucose readings every 2 weeks to a secure Web site for review and receipt of feedback from their endocrinologist. A1C and laboratory test results were collected at 0, 3, and 6 months.

RESULTS

The baseline parameters were not significantly different. Over a 6-month follow-up, A1C dropped from 8.8 to 7.6% (P < 0.001) in the intervention group compared with 8.5 to 8.4% (P = 0.51) in the control group.

CONCLUSIONS

The use of IBGMS significantly improved A1C levels in patients with type 2 diabetes treated with insulin.
Central Role of Fatty Liver in the Pathogenesis of Insulin Resistance in Obese Adolescents
Authors: D'Adamo Ebe , Cali Anna M.G. , Weiss Ram , Santoro Nicola , Pierpont Bridget , Northrup Veronika , Caprio Sonia
Published: July 2010

OBJECTIVE

We evaluated the role of fatty liver in the alteration of insulin sensitivity and β-cell function in two groups of obese adolescents, differing in hepatic fat content (hepatic fat fraction [HFF]) but with similar intrabdominal intramyocellular lipid content (IMCL) and overall degree of obesity.

RESEARCH DESIGN AND METHODS

We studied 23 obese adolescents with high HFF (HFF >5.5%) and 20 obese adolescents with low HFF (HFF <5.5%), matched for age, Tanner stage, BMI z score, and percentages of body fat, visceral fat, and IMCL. All subjects underwent an oral glucose tolerance test and a two-step hyperinsulinemic-euglycemic clamp, magnetic resonance imaging and 1H nuclear magnetic resonance to assess abdominal fat distribution, HFF, and IMCL, respectively.

RESULTS

The high HFF group showed significantly lower whole-body insulin sensitivity index (P = 0.001) and estimates of insulin secretion (P = 0.03). The baseline hepatic glucose production (EGP) rate was not different between the two groups. Suppression of EGP was significantly lower (P = 0.04) in the high HFF group during low-dose insulin; no differences were observed during the second step. Baseline fatty acids, glycerol concentrations, and clamp suppression of glycerol turnover did not differ between the groups. During the second step, the glucose disposal rate was significantly lower (P = 0.01) in the high HFF group.

CONCLUSIONS

Fatty liver, independent of visceral fat and IMCL, plays a central role in the insulin-resistant state in obese adolescents.
Antimicrobial activity and total content of polyphenols of Rheum L. species growing in Poland
Authors: Kosikowska Urszula , Smolarz Helena , Malm Anna
Published: July 2010

In the crude ethanol extracts obtained from the rhizome and roots of Rheum palmatum L., Rheum undulatum L. and Rheum rhaponticum L. growing in Poland concentration of polyphenols ranged from 46.11 to 76.45 mg/g. Concentration of tannins ranged from 7.07% to 8.67%, while anthracene derivatives and anthraquinones varied by species - R. palmatum measured 36.3 and 34 mg/g, while R. undulatum or R. rhaponticum did not exceed 20.4 and 18.1 or 19.8 mg/g and 16.6 mg/g, respectively. Using a broth microdilution method it was found that all of the Rheum spp. extracts were more active against reference strains of Gram-positive bacteria (Staphylococcus spp.) than against those of Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis). The strongest inhibitory effect against Staphylococcus spp. was exerted by R. undulatum extract with MIC = 125–250 μg/mL. The moderate in vitro antibacterial activity of R. undulatum suggests that this plant, often used in the European cuisine to improve flavour, may be also important and useful as an alternative or auxiliary medicine remedy in the treatment of uncomplicated superficial infections caused especially by clinically important staphylococci, potentially pathogenic S. aureus or opportunistic S. epidermidis.
Adherence to Behavioral Interventions for Urge Incontinence When Combined With Drug Therapy: Adherence Rates, Barriers, and Predictors
Authors: Borello-France Diane , Burgio Kathryn L. , Goode Patricia S. , Markland Alayne D. , Kenton Kimberly , Balasubramanyam Aarthi , Stoddard Anne M. ,   Urinary Incontinence Treatment Network
Published: July 2010

Background

Behavioral intervention outcomes for urinary incontinence (UI) depend on active patient participation.

Objective

The purpose of this study was to describe adherence to behavioral interventions (pelvic-floor muscle [PFM] exercises, UI prevention strategies, and delayed voiding), patient-perceived exercise barriers, and predictors of exercise adherence in women with urge-predominant UI.

Design

This was a prospectively planned secondary data analysis from a 2-stage, multicenter, randomized clinical trial.

Patients and Intervention

Three hundred seven women with urge-predominant UI were randomly assigned to receive either 10 weeks of drug therapy only or 10 weeks of drug therapy combined with a behavioral intervention for UI. One hundred fifty-four participants who received the combined intervention were included in this analysis.

Measurements

Pelvic-floor muscle exercise adherence and exercise barriers were assessed during the intervention phase and 1 year afterward. Adherence to UI prevention strategies and delayed voiding were assessed during the intervention only.

Results

During intervention, 81% of women exercised at least 5 to 6 days per week, and 87% performed at least 30 PFM contractions per day. Ninety-two percent of the women used the urge suppression strategy successfully. At the 12-month follow-up, only 32% of the women exercised at least 5 to 6 days per week, and 56% performed 15 or more PFM contractions on the days they exercised. The most persistent PFM exercise barriers were difficulty remembering to exercise and finding time to exercise. Similarly, difficulty finding time to exercise persisted as a predictor of PFM exercise adherence over time.

Limitations

Co-administration of medication for UI may have influenced adherence.

Conclusions

Most women adhered to exercise during supervised intervention; however, adherence declined over the long term. Interventions to help women remember to exercise and to integrate PFM exercises and UI prevention strategies into daily life may be useful to promote long-term adherence.
Investigating population dynamics in ungulates: Do hunting statistics make up a good index of population abundance?
Authors: Imperio Simona , Ferrante Massimiliano , Grignetti Alessandra , Santini Giacomo , Focardi Stefano
Published: July 2010

Time series analysis plays an important role in the detection of mechanisms that drive population fluctuations. However, long time series are rare, with ungulate data sets usually not exceeding 50 years. In this article, we describe a long‐term data set of population density indices of five ungulate species obtained from the analysis of bag records collected in the Castelporziano Preserve, Rome, Italy. Hunting statistics are often used as proxies for population density; however, in the case of long time series for large mammals, there are no comparative studies to assess the validity of such data. We evaluated the ungulate time series, using two different approaches: we 1) compared hunting statistics with independent animal counts, and 2) assessed whether or not habitat composition of the drive areas was representative of habitat availability in the whole estate. Regressions between bag data and animal counts gave significant results only for three species, whereas bag data corrected for hunted area were significantly correlated to animal counts for all five species. The results suggest that use of bag records not corrected for hunting effort and without any previous validation could lead to misleading estimates of abundance indices. Finally, our analysis showed that density indices of the five species were not significantly affected by the selection of habitats where hunting drives were organised. Our data set may contribute to the understanding of ungulate ecology in the Mediterranean environment.