bluuebunny/crossref_metadata_2025 huggingface dataset:
Emission Rates, Survival, and Modeled Dispersal of Viable Pollen of Creeping Bentgrass
Authors: Pfender W. , Graw R. , Bradley W. , Carney M. , Maxwell L.
Published: November 2007

Dispersal and deposition of pollen of creeping bentgrass (Agrostis stolonifera L.) was estimated by using CALPUFF, a complex model originally developed to simulate dispersal of particulates and other air pollutants. In field experiments, peak pollen emission rates (8 × 106 pollen grains per min per m2 of a creeping bentgrass stand) occurred between 1000 and 1200 h. Pollen survival under outdoor conditions decreased exponentially with time, and only 1% survived for 2 h. CALPUFF simulations showed deposition of 100,000 viable pollen grains per m2 at distances of 2 to 3 km from the source field, and deposition of one pollen grain per 10 m2 at distances of 4.6 to 6.7 km from the source field. Pattern of simulated deposition varied with weather conditions and, to a lesser extent, source field size. Simulation of dispersal by a small thermal vortex produced deposition of one grain per 10 m2 at 15.3 km from the source field. Overall, the deposition modeling results suggest that pollen‐mediated gene flow is likely at distances of 2 to 3 km from a source field, and possible at distances up to 15 km.
Relationships between Blue‐ and Red‐based Vegetation Indices and Leaf Area and Yield of Alfalfa
Authors: Hancock Dennis W. , Dougherty Charles T.
Published: November 2007

The need for site‐specific yield assessments of alfalfa (Medicago sativa L.) has spurred interest in developing methods to remotely sense biomass at harvest. Relationships between reflectance‐based vegetation indices (VIs) and yield and yield‐components of alfalfa have not been fully characterized. The objectives of this study were to evaluate the relationships between blue‐ and red‐reflectance based VIs and canopy variables such as leaf area index (LAI), mass shoot−1, shoot length, and alfalfa yield. Canopy reflectance was obtained with two reflectance spectrometers 1 d before each of five harvests in 2005 within rainfed and subsurface drip‐irrigated alfalfa. Blue‐ and red‐based normalized difference vegetation indices (NDVIs) and wide dynamic range vegetation indices (WDRVIs) at three levels of a near‐infrared (NIR) reflectance‐scalar (‘α’ = 0.1, 0.05, and 0.01) were calculated and regressed on alfalfa canopy variables. A quadratic‐plateau model was used to determine when VIs no longer detected yield increments. Both blue‐ and red‐based NDVIs and WDRVIs exhibited significant (P < 0.0001) saturative responses to LAI, yield components, and dry matter (DM) yield. Decreasing α widened the estimable yield range (0–1.82 vs. 0–2.76 Mg ha−1 and 0–2.60 vs. 0–3.74 Mg ha−1, respectively) of both blue‐ and red‐based WDRVIs. Significant (P < 0.0001) yield regression models within the effective range of the VIs (<Yieldmax) were found within two harvests in 2005 and when data were pooled across all harvests. These results indicate that the use of a NIR reflectance‐scalar can extend the range of herbage biomass (to 3.74 and 2.76 Mg ha−1, respectively) within which blue‐ and red‐based indices may be used to estimate alfalfa yield.
Nitrate Leaching in Overseeded Bermudagrass Fairways
Authors: Wu Laosheng , Green Robert , Yates Marylynn V. , Pacheco Porfy , Klein Grant
Published: November 2007

Maintaining high visual quality of turfgrass requires intensive management. Nitrogen fertilizer inputs in golf‐course turfgrass have raised some concerns regarding potential nitrate leaching into groundwater. This study investigated nitrate leaching from an overseeded bermudagrass (Cynodon dactylon(L.) Pers. ×C. transvaalensisBurtt‐Davy) managed as a golf course fairway (mowing height in 1.3 cm). The study was conducted from 1994 to 1997, with two soil types (sandy loam and loamy sand), two irrigation regimes, and two N fertilization programs representing the typical resort‐turfgrass management practices in the semiarid southern California. Leachate was collected and its volume was measured from lysimeter assemblies each consisting of five metal cylinders. Results showed that the nitrate concentration and mass of the leachate from the loamy sand was lower than that from the sandy loam soil. The difference was attributed to N immobilization and clipping removal. The volume of leachate was greater in the loamy sand than in the sandy loam due to the higher water holding capacity of the latter. Average nitrate concentration of the leachate was lower than that of the irrigation water in five out of the six seasons, implying that if turfgrass is properly managed, it may provide an opportunity to mitigate nitrate loading to surface and ground waters, even when N application rate is high.
Genetic Mapping of a Triticum monococcum‐derived Powdery Mildew Resistance Gene in Common Wheat
Authors: Miranda L. M. , Perugini L. , Srnić G. , Brown‐Guedira G. , Marshall D. , Leath S. , Murphy J. P.
Published: November 2007

Powdery mildew of wheat (Triticum aestivum L.) is a major fungal disease caused by Blumeria graminis DC f. sp. tritici A microsatellite linkage map was developed for the T. monococcum‐derived powdery mildew resistant gene present in the North Carolina germplasm line NCBGT96A6 (NCA6). Genetic analysis of F2‐derived lines from the cross NCA6 × ‘Saluda’ indicated a single gene controlled powdery mildew resistance. Four microsatellite markers linked to the NCA6 Pm gene mapped to chromosome 7AL. The most likely order was Xcfa2123‐0.9 cM–Xbarc121‐1.7 cM resistance gene/Xcfa2019‐3.0 cM‐Xgwm332 A detached‐leaf test indicated the disease reaction response of the NCA6 Pm gene was different from the five known alleles at the Pm1 locus on 7AL. Deletion interval mapping showed a large physical to genetic distance ratio for these microsatellite marker loci. This may be due to suppressed recombination between the introgressed T. monococcum segment and the homologous region of the T. aestivum cultivar Saluda. Our results suggested that the NCA6 Pm gene is likely a novel source of resistance to powdery mildew but additional allelism studies are needed to establish the relationship between this locus and the other known Pm loci on 7AL.
Production and Heterosis Analysis of Rice Autotetraploid Hybrids
Authors: Tu Shengbin , Luan Li , Liu Yuhua , Long Wenbo , Kong Fanlun , He Tao , Xu Qiongfang , Yan Wengui , Yu Maoqun
Published: November 2007

Poor fertility is the main barrier for utilizing heterosis between the two rice (Oryza sativa L.) subspecies, indica and japonica Recently, the development of autotetraploid hybrids (2n = 4x = 48) has been suggested as a new method for increasing heterosis in hybrid rice. Using standard experimental protocols, the elite diploid rice male sterile, maintainer, and restorer lines were colchicine‐doubled, and autotetraploid counterparts were obtained. Seven resulting hybrids were analyzed for heterobeltiosis (HB), where the F1 was compared to the male parent, and the degree of heterosis, where the F1 was compared to the diploid commercial hybrid, Shanyou 63. The HB among the autotetraploid hybrids ranged from 1.4 to 105.9% for the productive panicles per plant, 0.5 to 74.3% for total kernels per panicle, 17.6 to 255.7% for filled kernels per panicle, and 9.6 to 130.4% for seed set. Improvements in these yield components resulted in the HB for kernel yield ranging from 64.8 to 672.7% among the seven hybrids. Hybrids T461A/T4002 and T461A/T4193 yielded 46.3 and 38.3% more, respectively, than Shanyou 63, and all other hybrids but one yielded the same or more than Shanyou 63. The high heterosis for yield suggests that hybrid sterility between two rice subspecies may be overcome by using tetraploid lines followed by intensive selection. Also, the gigantic features of the autotetraploid hybrids may establish a plant structure able to support the higher yield.
Genetic Variation in Three Native Plant Species across the State of Minnesota
Authors: Moncada Kristine M. , Ehlke Nancy J. , Muehlbauer Gary J. , Sheaffer Craig C. , Wyse Donald L. , DeHaan Lee R.
Published: November 2007

Restoration of native plant communities requires adapted germplasm; thus, information is needed to guide native seed collection and production. Analysis of genetic variation has potential to provide insight into diversity and relatedness of natural populations. Our objectives were to examine genetic diversity of native species in Minnesota to discover if variation is related to biomes or distance, and possibly to develop seed collection zones. Our study included prairie cordgrass (Spartina pectinata), purple prairie clover (Dalea purpurea), and spotted joe‐pye weed (Eupatorium maculatum). Using amplified fragment length polymorphisms, we analyzed 100 samples from eight populations for prairie cordgrass, 152 samples from nine populations for purple prairie clover, and 127 samples from 10 populations for spotted joe‐pye weed. We found moderate to high levels of genetic diversity within each species. Small populations were not necessarily lower in diversity than larger ones. Analysis of molecular variance results indicate clear population differentiation. However, rather than displaying geographic or ecological associations, the variation had discontinuous patterns. Therefore, we were not able to develop unambiguous recommendations for seed collection. We discuss the applicability of molecular markers in detecting adaptive potential.
Identification, Characterization and Expression of Drought Related alpha‐Crystalline Heat Shock Protein Gene (GHSP26) from Desi Cotton
Authors: Maqbool Asma , Zahur Muzna , Irfan Muhammad , Qaiser Uzma , Rashid Bushra , Husnain Tayyab , Riazuddin Shiekh
Published: November 2007

In response to water deficit stress, plants show quantitative and qualitative differences in gene expression. By using differential display and RACE (rapid amplification of cDNA ends) polymerase chain reaction (PCR) techniques an alpha crystalline‐type small heat shock protein gene (GHSP26) was isolated and characterized from Gossypium arboreum L. Alignments of 1108 bp genomic and 1026 bp cDNA sequences revealed that the GHSP26 gene comprises a single open reading frame of 230 amino acids and it contains a single intron. The gene product contains the highly conserved alpha crystalline region, spanning amino acid residues 133 to 217 and a Met‐rich region from 94 to 117aa at the N terminus. Predicted amino acid sequence shares 65%, 63%, 59%, 58%, 56%, 55%, 53%, and 22% identities with Petunia hybrida, Nicotiana tabacum, Arabidopsis thaliana, Zea mays, Agrostis stolonifera, Triticum aestivum, Oryza sative, and Nitrosococcus oceani, respectively. Expression profile of the gene was studied from leaf, stem, and root tissues, through reverse transcriptase polymerase chain reaction (RT‐PCR) and quantitative real‐time RT‐PCR analysis. The results indicated that the gene was expressed in all tissues tested in both fully hydrated and dehydrated plants. However, the gene was 100‐fold more abundant in dehydrated leaves, while only two‐fold abundant in stressed root and stem as compared to control tissues.
Heritability Estimates and Response to Selection for Resistance to Mycosphaerella Blight in Pea
Authors: Zhang Roger X. , Gossen Bruce D.
Published: November 2007

Resistance to Mycosphaerella pinodes in field pea (Pisum sativum L) is a quantitative trait, and expression of resistance is substantially influenced by environment. The disease reaction to mycosphaerella blight of four crosses (F2:4 and F2:5 populations) was assessed in field trials at Vegreville, AB, Canada. Broad‐sense heritability of resistance was quite high (0.62–0.81). Narrow‐sense (realized) heritability was moderate (0.43–0.57), indicating that additive genetic factors contributed substantially to the resistance phenotype. Significant improvement in resistance among the lines developed from selected individuals indicates that genetic improvement based on progeny testing would be effective. This study demonstrated that resistance to M. pinodes can be improved through progeny selection from crosses of the most resistant lines.
Molecular Mapping of the Russian Wheat Aphid Resistance Gene Dn2414 in Wheat
Authors: Peng Junhua , Wang Hong , Haley Scott D. , Peairs Frank B. , Lapitan Nora L.V.
Published: November 2007

Russian wheat aphid (RWA) [Diuraphis noxia (Kurdjumov)] is an important pest of wheat (Triticum aestivum L.) in several production areas of the world. The most effective and economical approach for controlling RWA is to use resistant cultivars. A wheat line, ST‐ARS 02RWA2414‐11 (2414‐11), showed a high level of resistance to RWA biotype 2. Our objectives were to map the resistance gene and develop polymerase chain reaction (PCR)–based markers for marker‐assisted selection (MAS). A mapping population of 212 F2 individuals was developed from a cross of 2414‐11 and the susceptible cultivar Yuma. The F2 individuals and F2:3 families were infested using biotype 2 RWA. The RWA resistance of 2414‐11 is controlled by a single major gene, provisionally designated as Dn2414 Using standard PCR, 30 marker loci were found to be linked to Dn2414 with recombination frequencies (θ) of 0.00 to 0.27 and logarithm of the odds to the base 10 (LOD) scores of 7.6 to 66.1. Of the 30 markers, 26 were tightly linked to Dn2414 with θ ≤ 0.05. A genetic map was constructed consisting of 31 loci spanning a region of 34.7 cM. The close linkage of Dn2414 with several rye chromosome 1R short arm (1RS)‐specific simple sequence repeat markers and low θ values around the Dn2414 gene indicate that Dn2414 is located on chromosome 1RS.1BL (translocation chromosome with IRS and wheat chromosome 1B long arm). Phenotypic and marker profiles of 2414‐11 and its relatives are the same as other lines known to carry Dn7 The Dn2414 gene is thus located on 1RS arm, and the large number of PCR markers will be valuable for MAS of this gene.
Selections of an Olive Breeding Program Identified by Microsatellite Markers
Authors: Díaz Aurora , De la Rosa Raúl , Rallo Pilar , Muñoz‐Díez Concepción , Trujillo Isabel , Barranco Diego , Martín Antonio , Belaj Angjelina
Published: November 2007

This work reports on the use of 10 microsatellites for identifying and testing the paternity of the first 17 selections of an olive (Olea europaea L.) breeding program in Córdoba, Spain. The usefulness of the microsatellites was confirmed by the high discrimination power and polymorphism information content values and by the low probability of identity found in the 24 main Spanish cultivars. In the selections from the crosses ‘Picual’ × ‘Arbequina’ and ‘Frantoio’ × Picual, the putative male parent was the expected one. In the individuals coming from putative selfings of Arbequina and Picual and from the putative crosses Frantoio × Arbequina, Arbequina × Frantoio and Picual × Frantoio, the male paternity assigned a priori was wrong. Only three microsatellites were needed to discriminate all the selections and to differentiate them from the 24 main cultivars. The probability of having a seedling with a certain allele combination for the 10 microsatellites was 7.63e‐06, in the case of Arbequina × Picual and the reciprocal cross, and 1.53e‐05 for the cross Frantoio × Picual. A dendrogram generated using the Dice similarity coefficient and the unweighted pair group method with arithmetic mean (UPGMA) agglomeration method showed every selection grouped with one of their two parents.
Biofuels in Brazil: An Overview
Authors: Nass Luciano Lourenço , Pereira Pedro Antônio Arraes , Ellis David
Published: November 2007

The demand for food, fuel, and energy resources continues to increase worldwide. Currently, there are many international efforts aimed at finding renewable, sustainable, and environment friendly solutions for these problems. The spiraling price of petroleum and the adverse effects of using nonrenewable resources are major reasons for increased interest in renewable sources of energy. Brazil, the fifth largest and fifth most populated country in the world, has been developing successful initiatives in renewable sources of energy for more than 75 yr. The production and use of ethanol from sugarcane (Saccharum L.) is a global model for ethanol production, distribution, and use; therefore, the Brazilian ethanol industry has attracted interest from scientists, producers, and governments of both developed and developing countries. Like ethanol, biodiesel is also receiving increased interest in Brazil, with the source material for biodiesel production varying widely between regions. Several oleaginous species have been used, and others are being investigated as potential sources for biodiesel production. Biodiesel was introduced much later than ethanol in Brazil with the formation of the Brazilian Energy Matrix in January 2005 and a mandatory use of at least 2% (B2) biodiesel by 2008 and 5% (B5) by 2013. This paper presents a view of the historic development of ethanol and biodiesel programs in Brazil, emphasizing the strategic role of plant genetic resources as a pillar to support future improvements through plant breeding.
Soil Compaction and Soybean Seedling Emergence
Authors: Hyatt Jessica , Wendroth Ole , Egli Dennis B. , TeKrony Dennis M.
Published: November 2007

Soil compaction can cause nonuniform emergence and poor field stands. The effect of soil compaction on soybean [Glycine max (L.) Merr.] seedling emergence in controlled (greenhouse or growth chamber) environments was evaluated using seed lots from six cultivars with high standard germination but variable seed vigor (accelerated aging test). Soil compaction treatments providing a range of compactive efforts (CE) were imposed after planting in near‐cylindrical containers. As compaction increased from low (4.6 kJ m−3 CE) to high (22.9 kJ m−3 CE), emergence declined; however, high‐vigor seed consistently emerged better than low‐vigor seed. Emergence of high‐vigor seed lots remained >80% until compaction increased to 13.7 kJ m−3 CE, while low‐vigor seed lots had low emergence (<50%) even at the lowest compaction (4.6 kJ m−3 CE) level. Three seeds per container (spaced 3.81 cm apart) had consistently higher seedling emergence in compacted soil than one seed; however, seed size had no effect on emergence at any level of compaction. Seeds that did not emerge either germinated but remained under the soil crust or were dead (occurred more frequently in low‐vigor seed lots). Seedling emergence at 15 or 20°C in the growth chamber was less than at 25°C, and the effect of compaction was enhanced at lower temperatures. Seed lots with high vigor provided adequate seedling emergence following moderate levels of soil compaction (4.6 and 9.2 kJ m−3 CE). Thus, planting high‐vigor seed would be advantageous on soils that are susceptible to compaction.
Soybean Tolerance to Water‐Saturated Soil and Role of Resistance to Phytophthora sojae
Authors: Helms T. C. , Werk B. J. , Nelson B. D. , Deckard E.
Published: November 2007

There are differences among soybean [Glycine max (L.) Merr.] genotypes for tolerance to water‐saturated soil conditions. Phytophthora root rot caused by Phytophthora sojae (M.J. Kaufmann and J.W. Gerdemann) is problematic for soybean when the soil is excessively wet. Our objectives were (i) to determine if genotype‐by‐environment (G × E) interactions existed for yield between water‐saturated (irrigated) vs. control (nonirrigated) environments using 37 soybean genotypes; and (ii) to determine whether resistance and/or partial resistance to P. sojae was associated with tolerance to water‐saturated soil conditions. The G × E was significant between the water‐saturated treatment and control. Some genotypes that yielded well under control conditions did not yield well under saturated conditions. Based on yield, we identified eight genotypes that were tolerant and eight genotypes that lacked tolerance to water‐saturated soil conditions. These 16 genotypes were evaluated for resistance and partial resistance to Phytophthora using three virulence phenotypes. Those genotypes that were tolerant to water‐saturated soil conditions possessed either a major gene or good partial resistance to P. sojae. We concluded that resistance to P. sojae was an important factor that increased tolerance to water‐saturated soil, but that unknown other genetic factors were also important.
Charcoal Rot Disease Assessment of Soybean Genotypes Using a Colony‐Forming Unit Index
Authors: Mengistu Alemu , Ray Jeffery D. , Smith James R. , Paris Robert L.
Published: November 2007

Charcoal rot [Macrophomina phaseolina (Tassi) Goid] of soybean [Glycine max (L.) Merr.] is a disease of economic significance throughout the world. Progress in developing resistant genotypes has been hampered because of a lack of reliable and efficient methods for assessment of soybean genotypes. Researchers need a common system for classifying soybean genotypes for their reaction to M. phaseolina that is consistent across environments. We propose a classification system based on a colony‐forming unit index (CFUI), derived by dividing the colony‐forming unit (CFU) value of a given genotype by the CFU value of a susceptible standard. Four other assessment methods were compared and correlated to CFUI: percent height of stem discoloration measured at R7, foliar symptoms taken at R7, area under the disease progress curve based on foliar symptom data collected four times during the growing season up to R7, and the intensity of internal root and stem discoloration taken at R7 (root and stem severity [RSS]). Twenty‐four soybean genotypes in Maturity Groups III through V were evaluated in 2002 and 2003 in naturally and artificially infested fields. Based on the CFUI, four genotypes were classified as moderately resistant to M. phaseolina Among the disease assessment methods, RSS had the highest correlation with CFUI (r = 0.71 in 2002 and r = 0.69 in 2003). The CFUI provided a good measure of disease resistance across environments but was still time consuming. The RSS provided a less‐accurate but more‐rapid alternative that may be suitable for some breeding strategies.
Expression of cry1Fa in Bahiagrass Enhances Resistance to Fall Armyworm
Authors: Luciani Gabriela , Altpeter Fredy , Yactayo‐Chang Jessica , Zhang Hangning , Gallo Maria , Meagher Robert L. , Wofford David
Published: November 2007

Bahiagrass (Paspalum notatum var. saurae) is the predominant forage grass in Florida and in other subtropical regions. To improve pest resistance against fall armyworm [Spodoptera frugiperda (J. E. Smith)], an optimized cry1Fa gene encoding a δ‐endotoxin from Bacillus thuringiensis was synthesized, subcloned under the transcriptional control of the constitutive ubi1 promoter, and introduced into the bahiagrass cultivar Tifton 9 by particle bombardment. Three transgenic bahiagrass lines were generated using minimal transgene expression cassettes without vector backbone. Southern blot analyses showed independent cry1Fa transgene integration patterns for the three lines. Transcripts of cry1Fa were detected in all three transgenic lines by reverse transcriptase polymerase chain reaction. Cry1Fa protein was detected in two lines by immuno‐chromatography and quantitative Cry1Fa enzyme linked immunosorbent assay (ELISA). The Cry1Fa ELISA also indicated stable cry1Fa transgene expression in vegetative progeny plants of both lines. Cry1Fa expression levels correlated well to resistance levels determined by insect bioassays. An average mortality rate of 83% was observed when neonate larvae of fall armyworm were fed with transgenic leaves of the highest cry1Fa expressing line. These results indicate that minimal expression cassette technology supports stable and high level expression of cry1Fa in bahiagrass which can control fall armyworm, a devastating pest of forage grasses.
Feedstock Crop Genetic Engineering for Alcohol Fuels
Authors: Sticklen Mariam B.
Published: November 2007

One of the goals of the U.S. government is to have “cellulosic ethanol” produced from a variety of sources, including feedstock crop biomass (a mass of raw material used in alcohol fuels processing), because these biomass sources contain polysaccharides that can be converted into fermentable sugars. Furthermore, the feedstock biomass sources are renewable and could become available at a billion tonnes per year in the United States. There are three major steps associated with the conversion of feedstock biomass into cellulosic ethanol. The first is the production of hydrolysis enzymes such as microbial cellulases, which convert the cellulose of feedstock biomass into fermentable sugars. The second step is the pretreatment processes used to break down the recalcitrant lignocellulose complex of feedstock into more reactive intermediates and to remove the lignin residues so the cellulase enzymes can have access to cellulose. The third step is fermentation of sugars into ethanol. The first two steps are the subject of this review. Plant genetic engineering has been used to directly express heterologous versions of cellulase and hemicellulase enzymes in situ. Plants have also been genetically modified for less lignin content or for more digestible lignin. An increase in feedstock polysaccharides and an increase in overall crop biomass via crop genetic engineering have also been reported. This article reviews the advancements made in feedstock crop genetic engineering in the above areas and discusses possible near‐future perspectives.
An Empirically Derived Model of Field‐Scale Gene Flow in Winter Wheat
Authors: Gaines Todd A. , Byrne Patrick F. , Westra Philip , Nissen Scott J. , Henry W. Brien , Shaner Dale L. , Chapman Phillip L.
Published: November 2007

The potential introduction of wheat (Triticum aestivum L.) cultivars with transgenic traits has generated increased interest in pollen‐mediated gene flow (PMGF). The objectives of this study were to estimate wheat PMGF between commercial fields across multiple years and locations, and to compare estimates from large fields to those from smaller experimental plots. The study was conducted in a total of 56 commercial field locations in eastern Colorado in 2003, 2004, and 2005. We measured PMGF by tracking the movement of an imidazolinone herbicide resistance gene from resistant to susceptible cultivars, sampled at distances of 0.23 to 61 m. At least one sample from all 56 fields and from all 18 evaluated cultivars had detectable PMGF. The highest observed PMGF was 5.3% at 0.23 m. The farthest distance at which PMGF was detected was 61 m and the highest PMGF at that distance was 0.25%. Higher levels and greater distances of PMGF were detected in commercial fields than in experimental plots. Based on estimates from a generalized linear mixed model with a random location effect, the distance required to ensure 95% confidence that 95% of locations have PMGF less than 0.9% is 41.1 m for cultivars heading earlier than the pollen source and 0.7 m for cultivars heading later than the pollen source. These confidence limits should represent the highest levels of PMGF expected to occur in winter wheat in the west‐central Great Plains and will be useful for wheat biotechnology regulation.
Effect of Temperature on Microsomal Omega‐3 Linoleate Desaturase Gene Expression and Linolenic Acid Content in Developing Soybean Seeds
Authors: Byfield Grace E. , Upchurch Robert G.
Published: November 2007

The mechanism of temperature adaptation in plants, including the formation of polyunsaturates in seed storage lipids, most likely involves transcriptional as well as post‐translational regulation of fatty acid desaturase activity. The present investigation was conducted to measure changes in the transcript accumulation among the three members of the soybean [Glycine max (L.) Merr.] microsomal omega‐3 fatty acid desaturase gene family in response to altered growth temperature during seed development. Microsomal omega‐3 fatty acid desaturases catalyze the insertion of a third double bond into linoleic (18:2Δ9, 12) acid to produce linolenic (18:3Δ9, 12, 15) acid. At 35 d after flowering, transcript accumulation (normalized for soybean actin) of GmFAD3A decreased by 5‐ to 15‐fold, GmFAD3B by 2‐ to 9‐fold, and GmFAD3C by 2‐ to 3‐fold in seeds that developed in a warm (day/night [D/N] = 30/26°C) versus a normal (D/N = 26/22°C) or a cool (D/N = 22/18°C) environment. At this stage of seed development, decreased omega‐3 desaturase gene expression levels were positively associated with reductions of 39 to 50% in the linolenic acid content of seeds of three soybean varieties examined. Thus, transcriptional regulation of the microsomal omega‐3 fatty acid desaturase gene family likely accounts, at least in part, for the reduced linolenic acid levels in soybean seeds grown at elevated temperature.
Maize Biomass Yield and Composition for Biofuels
Authors: Dhugga Kanwarpal S.
Published: November 2007

With the world oil reserves projected to be depleted in about 40 years at the current pace of use, emphasis has shifted to alternative sources of liquid fuel. Currently, ethanol produced from ∼20% of corn (Zea mays L.) grain in the United States contributes ∼3.5% of the volume and 2.5% of the energy equivalent of annual gasoline consumption. Cellulosic biomass has the potential to contribute substantially to the biofuels pool. Corn is the single‐largest source of crop residue in the United States. An unaltered cell wall is recalcitrant to hydrolytic enzymes required for the conversion of its polysaccharide fraction into simple sugars before fermentation. Attempts at lowering lignin to increase stover digestibility are generally accompanied by a reduction in biomass. The complexity of the cellulose synthase system poses a challenge in increasing its activity through biotechnological means. Exploitation of natural variation may thus be a more productive route to increase the stover cellulose content. In comparison, the objective of reducing or altering hemicellulose for improved ethanol production as well as digestibility of the grain by monogastric animals may be relatively easier to accomplish through transgenic means. Availability of molecular tools for many of the steps in cell wall biosynthesis and modification has opened the heretofore inaccessible biotechnological avenues to alter the wall composition and perhaps structure for increased ethanol production.
An Additional Measure of Overall Effect Size for Logistic Regression Models
Authors: Allen Jeff , Le Huy
Published: November 2007

Users of logistic regression models often need to describe the overall predictive strength, or effect size, of the model’s predictors. Analogs of R2 have been developed, but none of these measures are interpretable on the same scale as effects of individual predictors. Furthermore, R2 analogs are not invariant to the base rate (overall proportion of successes), making it difficult to compare effect sizes across data sets. The authors propose a measure of overall effect size that is interpretable on the same scale as effects of individual predictors and is invariant to the base rate. They explore the properties of the overall odds ratio and illustrate its use through an example. They also provide interpretive guidance and illustrate how statistical software can be used to compute the proposed measure.
Effects of background substraction on differential kidney function measured by static scintigraphy with DMSA and dynamic scintigraphy with MAG 3
Authors: Smokvina A. , Grbac Ivanković S. , Licul V. , Girotto N.
Published: November 2007

The aim of this study was to assess the influence of background subtraction (BS) on estimation of differential kidney function (DF) on the static scintigraphy with 99mTc dimercaptosuccinic acid (DMSA) and dynamic scintigraphy with 99mTc mercaptoacetyltriglicine (MAG3) and to establish possible differences between DF values estimated with these methods. Patients, methods: Patients (n = 106) were selected among those scheduled to static and dynamic scintigraphies within 3 months, with no interim clinical and laboratory changes, regardless the kidney pathology. DF was estimated according to the uptake ratio method. Four background regions of interest (ROIs) were applied, identical for both studies, and DF values were recalculated after BS. The corrected values were compared to the values before correction, separately for DMSA and MAG3, and between the studies. The results showed that ROIs used introduce variable results for the same patients, predominantly when noncorrected DF values were <45%. There were no significant differences between DF values (corrected and noncorrected) obtained from static and dynamic scintigraphy in all groups of patients. Since numerous reasons can bring to the errors in DF estimation when BS is used, the conclusions are that it would probably be more accurate to avoid BS, particularly when DF values are compared in a patient follow-up, and when kidney function is normal. BS should be used, but always in the same way, only when there is a significant difference in kidney size, or when DF is <25%, since background activity is then considerable. MAG3 and DMSA can be equally used for DF estimation and their results compared in patient follow-up.
99mTc-MIBI SPECT in primary hyperparathyroidism
Authors: Thoma N. , Dietlein M. , Moka D. , Eschner W. , Faust M. , Schröder W. , von Hülst-Schlabrendorff M. , Ehses W. , Schicha H. , Schmidt M.
Published: November 2007

Aim of the study was to analyse the influence of a concomitant vitamin D deficiency on the results of 99mTc-MIBI studies in patients (pts) with primary hyperparathyroidism (pHPT). Patients, methods: Between January 1998 and May 2004, 71 pts with pHPT had undergone operation after a 99mTc-MIBI study of whom 54 pts (76%) had normal values of 25-OH-vitamin D3 and 17 pts (24%) had vitamin D deficiency. Results of a dual-phase 99mTc-MIBI protocol with SPECT were compared with histopathology. Results: In 54 pts with normal vitamin D values late SPECT images identified more lesions (n = 51, sensitivity 91%) than early planar (n = 45, sensitivity 82%) or late planar images (n = 50, sensitivity 88%). In 17 pts with vitamin D deficiency late SPECT images identified more lesions (n = 13, sensitivity 72%) than early planar (n = 10, sensitivity 56%) or late planar images (n = 10, sensitivity 56%) too. In pts with vitamin D deficiency the sensitivity of a 99mTc-MIBI SPECT study was lower than in those with normal vitamin D status (72% vs. 91%) and dependent on the value for PTH. However, the results did not reach statistical significance: early planar: p = 0.1625; late planar: p = 0.0039; 99mTc-MIBI SPECT: p = 0.1180. Conclusion: The likelihood of a pathological 99mTc-MIBI study being obtained in pts with pHPT is dependent on the parathyroid hormone level. However, a negative influence of a low vitamin D level on the scintigraphic detection rate of a parathyroid adenoma could not be proven which may be due to the low number of pts with vitamin D deficiency.
Is radioiodine therapy conducted too late in patients suffering from thyroid autonomy?
Authors: Happel C. , Döbert N. , Grünwald F. , Spilker L.
Published: November 2007

Aim: The effectiveness of radioiodine therapy (RIT) is proven. The aim of this study was to determine, how much time passes between diagnosis of thyroid autonomy or occurrence of functional and/or local symptoms on one hand and RIT on the other hand. Patients, methods: This retrospective study comprises 196 patients, who were treated with radioiodine for thyroid autonomy between 2002 and 2005. Evaluated parameters are begin of functional and/ or local symptoms, first scintigraphy with relevant Tc-Uptake as time point of primary diagnosis of thyroid autonomy and time point of implementation of RIT. Results: Between first scintigraphy with relevant Tc-Uptake and implementation of RIT 0–72 months passed (median: 3 months). 160 patients (81.6%) had a prior diagnosis of goitre by their general practitioner and 163 patients (83.3%) had a prior diagnosis of TSH suppression. The time period between first recommendation of RIT and implementation of RIT was 0–89 months (median: 2 months). In 142 patients (71.4%) functional and/or local symptoms were present over 73 months (median; range: 0–180 months) before the first scintigraphy with therapy relevant Tc-Uptake was conducted. Conclusion: Despite clear recommendations in corresponding guidelines too much time passes between first symptoms (median: 73 months), primary diagnosis of therapy relevant thyroid autonomy (median: 2 months) and implementation of RIT. Patients with functional and/or local symptoms should be examined for thyroid autonomy early. If thyroid autonomy is proven, RIT should be planned immediately, especially in high-risk patients.
Comparison of 18F-FDG and 67Ga-citrate in sarcoidosis imaging
Authors: Wehrschuetz M. , Bisail B. , Woltsche M. , Schwarz T. , Lanz H. , Sorantin E. , Aigner R. M. , Prager E.
Published: November 2007

Aim: 67Ga citrate has been used long and successfully to diagnose and stage sarcoidosis. 18F-fluorodeoxyglucose (18F-FDG) has been suggested as a positron emission tomography (PET) tracer for sarcoidosis imaging. This study aimed to analyze possible advantages of 18F-FDG-PET over 67Ga citrate scintigraphy during the primary assessment of patients with sarcoidosis. Patients and methods: Twentyfour patients (11 men, 13 women, aged 52 years ±12.4) with histologically proven sarcoidosis were investigated with 18F-FDG and 67Ga citrate. Equipment included a fullring PET scanner (ECAT EXACT HR+, Siemens/CTI, Knoxville TN, USA) and a double-headed gamma camera (ECAM, Siemens, Illinois, USA) for scintigraphy. The mean time difference between the two studies was 6.5 days (range: 5–8 days). Results: There was a significant difference in the detection of pulmonary and nonpulmonary sarcoidosis lesions between planar 67Ga citrate scans and 18F-FDG-PET images (<0.0021). A total of 64 lesions were detected with 67Ga citrate scans in the thorax and elsewhere with a mean of 2.6 lesions (4%) per patient, while 85 lesions were found with 18F-FDG-PET, with a mean of 3.5 lesions (4.1%) per patient. There was complete agreement between 18F-FDG and 67Ga citrate in thoracic manifestations in four (16.6%) patients, and in non-thoracic manifestations in five (20.8%) patients. The interobserver variability showed a kappa value of 0.79. Conclusion: 67Ga citrate and 18F-FDG are useful tracers for diagnostic evaluation of thoracic sarcoidosis. 18F-FDG seems to be more suitable for imaging the mediastinum, the bi-hilar lymph nodes, the posterior regions of the lungs and non-thoracic lesions. Further prospective studies are needed to clarify the role of both tracers in early diagnosis and staging of sarcoidosis, and to resolve questions concerning medical treatment and follow-up.
Graves' disease and radioiodine therapy
Authors: Eschner W. , Sudbrock F. , Weber I. , Marx K. , Dietlein M. , Schicha H. , Kobe C.
Published: November 2007

Aim: This study was performed to determine the results of ablative radioiodine therapy (RIT) when the achieved dose in the thyroid was above 200 Gy and to characterize predictive factors for treatment outcome. Patients, methods: A total of 571 consecutive patients were observed for 12 months between July 2001 and June 2004. Inclusion criteria were a confirmed diagnosis Graves' disease, compensation of hyperthyroidism and withdrawal of antithyroid drugs two days before preliminary radioiodine-testing and RIT. The intended dose was 250 Gy and the therapeutically achieved dose was calculated from serial uptake measurements. The end-point measure was thyroid function 12 months after RIT; success was defined as elimination of hyperthyroidism. The relation between success rate and the achieved dose, thyroid volume, age and sex of patients, TSH- and TRAb-values and presence of ophthalmopathy was analysed. Results: Relief from hyperthyroidism was achieved in 96% of patients who received more than 200 Gy, even for thyroid volumes >40 ml. The success of ablative RIT was not influenced by age or sex of patients, or by TSH- or TRAb values or concomitant ophthalmopathy. The mean achieved dose in the thyroid was 298 Gy with a standard deviation of 74.6 Gy. Conclusion: To achieve a dose of over 200 Gy with the above standard deviation, we recommend calculating an intended dose of 250 Gy and using a dosimetric approach with early and late uptake values in the radioiodine test, to allow early therapeutic intervention should the posttherapeutic thyroid dose fall unexpectedly below 200 Gy.
Myocardial sympathetic innervation in diabetic patients with symptomatic coronary artery disease
Authors: Eckert S. , Fricke H. , Körfer J. , Weise R. , Lindner O. , Tschöpe D. , Horstkotte D. , Burchert W. , Fricke E.
Published: November 2007

Aim: In non-diabetic patients, sympathetic innervation can be preserved even if there is major impairment of myocardial blood supply. Matters may be more complex in diabetic patients because denervation can be caused by cardiac autonomic neuropathy (CAN) or by ischemic injury. Our aim was to determine whether restrictions in myocardial blood supply have a pronounced influence on sympathetic innervation in diabetics and if this effect can be differentiated from CAN. Patients, methods: We analyzed 20 diabetics with advanced coronary artery disease (CAD) and without known CAN. We determined quantitative myocardial blood flow using 13N-ammonia-PET, myocardial viability with 18F-FDG, and cardiac innervation with 11C-HED. We investigated the relationship between regional HED retention, blood flow, and coronary flow reserve (CFR). Attenuated heart rate response to adenosine was taken as indicator for CAN (HR ratio). Results: There was minor correlation of segmental stress flow and HED retention (r2 = 0.063, p <0.0001). Correlation improved when stress flow as well as HED retention were normalized to the individual maximum (r2 = 0.162, p <0.0001). In nine patients, a HR ratio < 1.2 implicated subclinical CAN. Duration of diabetic disease or glycaemic control (HbA1c) did not correlate with mean HED retention in the viable segments, but with its variation coefficient. Conclusions: As in non-diabetic patients, a slight correlation exists between CFR and sympathetic innervation. The sensitivity of sympathetic nerves to reductions in CFR does not seem to be increased as compared to the results reported for non-diabetics. Besides impaired blood supply, long duration of diabetic disease and bad glycaemic control also seem to impair sympathetic innervation provoking higher heterogeneity.
Whole-body imaging of oncologic patients using 16-channel PET-CT
Authors: Oei M. L. , Weckesser M. , Franzius C. , Wormanns D. , Schober O. , Heindel W. , Juergens K. U.
Published: November 2007

Aim: This study evaluated a MDCT protocol for contrast-enhanced 16-channel PET-CT with regard to scan range and duration of a whole-body 18F-FDG PET-CT examination, the occurrence of contrast-material induced artefacts and quantitative assessment of CT attenuation. Patients, methods: 205 patients (51.9 ± 12.4 years) with different malignant tumours underwent whole-body PET-CT; the study protocol had been approved by the institutional review board. Contrast-enhanced MDCT (16 ˟ 1.5 mm; 120 ml Iomeprol 3 ml/s, 50 ml saline chaser bolus, scan delay 70 s; oral contrast) was also used for attenuation correction. From MDCT data mean scan range and duration, occurrence of contrast media-induced artefacts, and mean CT densities of jugular (jv) and subclavian (scv), superior (vcs) and inferior (vci) caval, portal (pv), and bilateral external iliac veins, pulmonary (ap) and iliac arteries, descending thoracic and abdominal aorta, all cardiac chambers, as well as both liver lobes, spleen, adrenal glands and kidneys were determined. Results: Attenuation corrected PET images were free of contrast media-related image artefacts. Homogeneous contrast enhancement was found in the mediastinal veins (right/left jv 171 ± 34/171 ± 35, scv 127 ± 50/127 ± 40, vcs 153 ± 36 HU) and arteries (e.g. ap 145 ± 26/151 ± 26). Cardiac chambers, abdominal vessels (e.g. vci 138 ± 24, pv 159 ± 25 HU), and parenchymal organs revealed sufficient and homogenous contrast-enhancement in all cases. No beam-hardening artefacts occurred in the neighbourhood of the subclavian veins. Conclusion: The chosen whole-body 18F-FDG 16-slice PET-CT protocol allowed for craniocaudal CT scanning with high vessel and parenchymal contrast revealing no IV contrast-media induced artefacts in attenuation-corrected PET data sets.
Aspects of 6-[18F]fluoro-L-DOPA preparation
Authors: Füchtner F. , Zessin J. , Wüst F. , Mäding P.
Published: November 2007

Aim: Replacement of the ecologically harmful solvent Freon 11 (CFCl3) by chloroform for the module-assisted preparation of 6-[18F]fluoro-L-DOPA based on the electrophilic radiofluorodestannylation of the precursor N-formyl- 3,4-di-tert-butoxycarbonyloxy-6-(trimethylstannyl)- L-phenylalanine ethyl ester. Materials, methods: The TRACERlab Fx FDOPA module (GE Medical Systems) was used for the preparation of 6-[18F]fluoro-L-DOPA. Cyclotron- produced [18F]F2 gas (5 GBq) was passed through a cooled solution (5°C) of the stannyl precursor (45 mg) in CDCl3 (10 ml). After the [18F]fluorination step, HCl (2 ml, 6 mol/l) was added to the solution. Then the reaction mixture was heated at 80°C for 5 min under vacuum to evaporate the chloroform. The hydrolysis to remove the protecting groups was completed by heating the closed reactor at 130°C for 8 min. After cooling to 20°C the reaction mixture was purified by HPLC with two polymer-based RP columns (PRP-1, 7 μm, 10 X 250 mm, Hamilton) using a solution of AcOH/AcONa (pH 4.7) as eluent. The 6-[18F]fluoro- L-DOPA fraction was collected and sterile filtrated. Results: Three types of stabilised chloroform were tested for the radiofluorination of the precursor. Only by use of deuterochloroform stabilised with silver no significant losses of radioactivity were observed. Thus, 6-[18F]fluoro-L-DOPA purified by HPLC was obtained in decay-corrected radiochemical yields of 25±3%, ready for human use. Conclusion: CDCl3 has proved to be a convenient solvent for the module-assisted preparation of 6-[18F]fluoro-L-DOPA. In this way the use of the polluting Freon 11 can be avoided.
Restaging of patients with lymphoma
Authors: Pfluger T. , Schneider V. , Hacker M. , Bröckel N. , Morhard D. , Hundt W. , Bartenstein P. , Becker C. , Tiling R. , la Fougère C.
Published: November 2007

Aim: Assessment of the clinical benefit of i.v. contrast enhanced diagnostic CT (CE-CT) compared to low dose CT with 20 mAs (LD-CT) without contrast medium in combined [18F]-FDG PET/CT examinations in restaging of patients with lymphoma. Patients, methods: 45 patients with non-Hodgkin lymphoma (n = 35) and Hodgkin's disease (n = 10) were included into this study. PET, LD-CT and CECT were analyzed separately as well as side-by-side. Lymphoma involvement was evaluated separately for seven regions. Indeterminate diagnoses were accepted whenever there was a discrepancy between PET and CT findings. Results for combined reading were calculated by rating indeterminate diagnoses according the suggestions of either CT or PET. Each patient had a clinical follow-up evaluation for >6 months. Results: Region-based evaluation suggested a sensitivity/specificity of 66/93% for LD-CT, 87%/91% for CE-CT, 95%/96% for PET, 94%/99% for PET/LD-CT and 96%/99% for PET/CE-CT. The data for PET/CT were obtained by rating indeterminate results according to the suggestions of PET, which turned out to be superior to CT. Lymphoma staging was changed in two patients using PET/ CE-CT as compared to PET/LD-CT. Conclusion: Overall, there was no significant difference between PET/LD-CT and PET/CE-CT. However, PET/CE-CT yielded a more precise lesion delineation than PET/LD-CT. This was due to the improved image quality of CE-CT and might lead to a more accurate investigation of lymphoma.