bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidative dissolution of ruthenium deposits onto stainless steel by permanganate ions in alkaline medium
Authors: Floquet Sébastien , Eysseric Catherine , Maurel Didier
Published: November 2008

During spent nuclear fuel reprocessing ruthenium is liable to form black ruthenium deposits on the stainless steel walls of process equipments. These deposits promote corrosion and can eventually obstruct the off-gas lines. The results of decontamination of 304L stainless steel test specimens covered with RuO(OH)2· x H2O deposits by permanganate ions in alkaline medium are described. The ruthenium deposits were dissolved by oxidation of RuO(OH)2 to RuO4
2− ions, while the permanganate ions were reduced to MnO4
2− ions and then to manganese dioxide MnO2. The parameters affecting the kinetics of oxidative dissolution of these deposits were examined. The results indicate that the oxidative dissolution kinetics depends on the instantaneous surface area of the deposit, and that the dissolution rate increases with the concentrations of MnO4
− and OH− ions.
Thermochromatographic studies of plutonium oxides
Authors: Hübener S. , Taut S. , Vahle A. , Bernhard Gert , Fanghänel Thomas
Published: November 2008

Trace amounts of oxidic plutonium species were studied by thermochromatography in silica glass columns in comparison to oxidic species of Th, Pa, U, Np, and Am. Humid oxygen was used as reactive admixture to the carrier gas helium. The thermochromatographic behavior of plutonium provides evidence for the oxidation of Pu(IV) to Pu(VI) with humid oxygen. The gas chromatographic transport of U, Np, and Pu is governed by the surface reaction

MO2(OH)2(g)↔MO3(ads)+H2O(g),

with M=U, Np, and Pu in the hexavalent state and competitive reactions of the actinide oxides with silica to nonvolatile compounds or solid solutions. There is good agreement with earlier volatility studies and the reported oxidation of PuO2 with water. The oxidation to PuO4 as claimed by Domanov [1] could not be confirmed.
Hydrolysis constants and complexation of Th(IV) with carboxylates
Authors: Sasaki Takayuki , Takaoka Y. , Kobayashi T. , Fujii Toshiyuki , Takagi I. , Moriyama Hirotake
Published: November 2008

The hydrolysis constants of Th(IV) were determined using the solvent extraction method in a NaClO4solution atI=0.1 and 25 °C. A trace amount of thorium below the solubility limit was used in order to avoid the formation of polynuclear species and colloids in the experiment. The values were compared with the literature data. Considering the effect of competitive hydrolysis reactions under weak acid conditions, the complexation constants of Th(IV) with a series of dicarboxylic acids containing different alkyl chain lengths were determined.
Pertechnetate immobilization with amorphous iron sulfide
Authors: Liu Yongjian , Terry Jeff , Jurisson Silvia S.
Published: November 2008

The reduction of pertechnetate (TcO4−) with freshly prepared amorphous iron sulfide was investigated. The amorphous iron sulfide (FeS) was shown to have an elemental composition of FeS0.97for all of the size fractions and a point of zero charge of pHpzc=7.4. Solubility studies of FeS in various buffers indicated that in the pH range 6.1–9.0, the concentrations of dissociated Fe2+and S2−were negligible. The reductive immobilization of TcO4−with FeS was shown to be accelerated by increasing ionic strength and strongly pH dependent. At pH values below the pHpzc, the positively charged FeS surface reacted much faster with TcO4−and had higher immobilization yields relative to the negatively charged FeS surface at pH values above pHpzc. The TcO4−−FeS reaction is consistent with a surface mediated reaction through ligand exchange. The TcO4−−FeS reductive immobilization reaction product was characterized by X-ray absorption near edge spectroscopy (XANES), extended X-ray absorption fine structure (EXAFS), Fourier transform infrared spectroscopy (FT-IR), and energy dispersive X-ray spectroscopy (EDS) and found to be predominantly TcO2. Studies on the reductive capacity of the FeS and the long term stability of the TcO4−−FeS reaction product under both anaerobic and aerobic environments shows the potential utility of thein situgaseous (hydrogen sulfide gas) immobilization technology in solidification of TcO4−by creating a FeS permeable reaction barrier in the vadose zone.
Fluorescent phosphinimine as possible precursor to an anionic and fluorescent sensor for Tc-99
Authors: Arrigo Leah M. , Galenas Miriam , Bassil Daniel B. , Tucker Sheryl A. , Kannan Raghuraman , Katti Kattesh V. , Barnes Charles L. , Jurisson Silvia S.
Published: November 2008

The trimethylsilyl-protected phosphinimines (9-anthracenyl)Ph2P=NSiMe3and (1-naphthyl)Ph2P=NSiMe3and the ion pairs [(9-anthracenyl)Ph2P=NH2+][MO4−] and [(1-naphthyl)Ph2P=NH2+][MO4−] with M=Re or Tc were synthesized and characterized by1H and31P NMR, UV-Vis and fluorescence spectroscopy, elemental analysis, and/or single crystal X-ray diffraction. Radiochemical studies performed using99mTc and186Re as the tracers for99Tc and Re found the selectivity of the phosphiniminium cations for pertechnetate in the presence of a variety of anions found in the environment to be excellent. The crystallographic data reported for the structures are as follows: [(9-anthracenyl)Ph2P=NH2+][ReO4−] (H21C26NO4PRe)2, monoclinic (P21/n),a=11.3047(5) Å,b=16.3983(8) Å,c=12.2469(6) Å, β=92.344(1)°,Z=4; [(9-anthracenyl)Ph2P=NH2+][TcO4−] (H21C26NO4PTc)3, monoclinic (P21/n),a=11.3619(4) Å,b=12.2203(3) Å,c=25.7794(13) Å,β=92.162(1)°,Z=4.
Extraction of Am(III) and lanthanides(III) with organo dithiophosphinic acids
Authors: Xu Qichu , Wu Jianfeng , Chang Yinzhong , Zhang Lixing , Yang Yusheng
Published: November 2008

Extraction of Am(III) and Ln(III) from NaClO4medium has been investigated with di(2-ethylhexyl) dithiophosphoric acid, di(2-ethylhexyl) monothiophosphoric acid, di(2-ethylhexyl) monothiophosphinic acid, octylphenyl dithiophosphinic acid and 11 kinds of dialkyl dithiophosphinic acids (alkyl = hexyl, heptyl, octyl, nonyl, 2-ethylhexyl, 1-methylheptyl, phenyl, chlorophenyl, methylphenyl, 2,5-dimethylphenyl, and 3,5-dichloro-4-methylphenyl) in xylene. The effect of chemical structures of those extractants on separation capability has been studied. The relationship between the slope value of the lgD−pH and extraction conditions can be described as: lgS=alg(CHA/CMS/4)+b. In the presence of macro amounts of Eu(ClO4)3, the formula, lg SFAm/Eu=B−2lg(CHL−DEu/(DEu+1)CEu), can well describe the relationship between separation factor and the extraction condition. A high separation factor (SFAm/Eu=2500) is obtained by solvent extraction from 1 mol/L NaNO3solution with 0.5 mol/L di(2-ethylhexyl) dithiophosphinic acid in toluene.
Radiosynthesis of dimethyl-2-[18F]-(fluoromethyl)-6-methyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate for L-type calcium channel imaging
Authors: Sadeghpour H. , Jalilian A. R. , Shafiee A. , Akhlaghi M. , Miri R. , Mirzaei M.
Published: November 2008

Dimethyl 2-(fluoromethyl)-6-methyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate 4a, a fluorinated nifedipine analog, has been shown to elicit significant calcium channel blocker activity using a guinea pig ileal longitudinal smooth muscle model. In order to perform biological studies for detection of L-type calcium channel distribution, we decided to prepare the [18F]-labeled compound. The latter compound was prepared in no-carrier-added (n.c.a.) form from dimethyl 2-(bromomethyl)-6-methyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate 2 in one step at 80 °C in Kryptofix[222]/K[18F]F and acetonitrile as a solvent in 15 min. Column chromatography afforded the radiochemically pure compound in 20 min. Radiochemical purity of the18F-nifedipine was determined by RTLC and HPLC (>98%) and specific activity of 21–48 GBq/μmol (EOB).
Immunoanalysis indicates that the sodium iodide symporter is not overexpressed in intracellular compartments in thyroid and breast cancers
Authors: Peyrottes Isabelle , Navarro Valerie , Ondo-Mendez Alejandro , Marcellin Didier , Bellanger Laurent , Marsault Robert , Lindenthal Sabine , Ettore Francette , Darcourt Jacques , Pourcher Thierry
Published: November 2008

Objective

The active transport of iodide into thyroid cells is mediated by the Na+/I− symporter (NIS) located in the basolateral membrane. Strong intracellular staining with anti-NIS antibodies has been reported in thyroid and breast cancers. Our initial objective was to screen tumour samples for intracellular NIS staining and then to study the mechanisms underlying the altered subcellular localization of the transporters.

Methods

Immunostaining using three different anti-NIS antibodies was performed on paraffin-embedded tissue sections from 93 thyroid or breast cancers. Western blot experiments were carried out to determine the amount of NIS protein in 20 samples.

Results

Using three different anti-NIS antibodies, we observed intracellular staining in a majority of thyroid tumour samples. Control immunohistochemistry and western blot experiments indicated that this intracellular staining was due to non-specific binding of the antibodies. In breast tumours, very weak intracellular staining was observed in some samples. Western blot experiments suggest that this labelling is also non-specific.

Conclusions

Our results strongly indicate that the NIS protein level is low in thyroid and breast cancers and that the intracellular staining obtained with anti-NIS antibodies corresponds to a non-specific signal. Accordingly, to increase the efficiency of radiotherapy for thyroid cancers and to enable the use of radioiodine in the diagnosis and therapy of breast tumours, improving NIS targeting to the plasma membrane will not be sufficient. Instead, increasing the expression level of NIS should remain the major goal of this field.
Structure, innervation, mechanical properties and reflex activation of a striated sphincter in the vestibule of the cat vagina
Authors: Lagunes-Córdoba Roberto , Tsutsumi Víctor , Muñoz-Martínez E J
Published: November 2008

Vaginal constriction might be important for reproduction in mammals, but existing information is both limited and controversial. This paper shows the structure, mechanical properties, innervation and reflex response of a striated sphincter in the vestibule of the cat vagina. A Foley catheter coupled to a pressure transducer detected in the lumen of the vestibule a pressure wave that was induced by stimulation of the external branch of the motor pudendal nerve. The peak pressure of the wave induced by bilateral stimulation (30.6 cm H2O) was about double of the peak pressure wave induced unilaterally. The tetanus/twitch amplitude ratio was 4.5. The sphincter that produces the increase in vaginal pressure fatigues slowly. Digital, point-to-point summation of unilateral waves was greater than the wave induced bilaterally. Summation of the pressure wave induced by the separate stimulation of the terminal motor branches was also greater than the wave induced by the entire motor nerve. This might reflect multiple innervation of muscle fibres. Single, controlled probing of the vaginal vestibule induced a reflex discharge in the motor nerve. Repetitive probing (10 Hz) induced a motor nerve post-discharge lasting >1 min. The vaginal sphincter is two-half rings of striated muscle fibres in the wall of the vaginal vestibule; the fibres end freely in the dorsal and ventral midlines. Penetration of the vestibule by the penis might trigger sustained contraction of the vaginal sphincter.
Effects of heat stress during in vitro maturation on cytoplasmic versus nuclear components of mouse oocytes
Authors: Wang Jun-Zuo , Sui Hong-Shu , Miao De-Qiang , Liu Na , Zhou Ping , Ge Li , Tan Jing-He
Published: November 2008

The objectives of this study were to investigate the effect of heat stress duringin vitromaturation on the developmental potential of mouse oocytes and to determine whether the deleterious effect was on the nuclear or cytoplasmic component. While rates of oocyte nuclear maturation (development to the metaphase II stage) did not differ from 37 to 40 °C, rates for blastocyst formation decreased significantly as maturation temperature increased from 38.5 to 39 °C. Chromosome spindle exchange showed that while blastocyst formation did not differ when spindles maturedin vivoorin vitroat 37, 40 or 40.7 °C were transplanted intoin vivomatured cytoplasts, no blastocyst formation was observed whenin vivospindles were transferred into the 40 °C cytoplasts. While oocytes reconstructed between 37 °C ooplasts and 37 or 40 °C karyoplasts developed into 4-cell embryos at a similar rate, no oocytes reconstituted between 40 °C ooplasts and 37 °C spindles developed to the 4-cell stage. Immunofluorescence microscopy revealed impaired migration of cortical granules and mitochondria in oocytes matured at 40 °C compared with oocytes matured at 37 °C. A decreased glutathione/GSSG ratio was also observed in oocytes matured at 40 °C. While spindle assembling was normal and no MAD2 was activated in oocytes matured at 37 or 40 °C, spindle assembling was affected and MAD2 was activated in some of the oocytes matured at 40.7 °C. It is concluded that 1) oocyte cytoplasmic maturation is more susceptible to heat stress than nuclear maturation, and 2) cytoplasmic rather than nuclear components determine the pre-implantation developmental capacity of an oocyte.
Direct Evidence That Genetic Variation in Glycerol-3-Phosphate and Malate Dehydrogenase Genes (Gpdh and Mdh1) Affects Adult Ethanol Tolerance in Drosophila melanogaster
Authors: Eanes Walter F , Merritt Thomas J S , Flowers Jonathan M , Kumagai Seiji , Zhu Chen-Tseh
Published: November 2008

Many studies of alcohol adaptation in Drosophila melanogaster have focused on the Adh polymorphism, yet the metabolic elimination of alcohol should involve many enzymes and pathways. Here we evaluate the effects of glycerol-3-phosphate dehydrogenase (Gpdh) and cytosolic malate dehydrogenase (Mdh1) genotype activity on adult tolerance to ethanol. We have created a set of P-element-excision-derived Gpdh, Mdh1, and Adh alleles that generate a range of activity phenotypes from full to zero activity. Comparisons of paired Gpdh genotypes possessing 10 and 60% normal activity and 66 and 100% normal activity show significant effects where higher activity increases tolerance. Mdh1 null allele homozygotes show reductions in tolerance. We use piggyBac FLP–FRT site-specific recombination to create deletions and duplications of Gpdh. Duplications show an increase of 50% in activity and an increase of adult tolerance to ethanol exposure. These studies show that the molecular polymorphism associated with GPDH activity could be maintained in natural populations by selection related to adaptation to alcohols. Finally, we examine the interactions between activity genotypes for Gpdh, Mdh1, and Adh. We find no significant interlocus interactions. Observations on Mdh1 in both Gpdh and Adh backgrounds demonstrate significant increases in ethanol tolerance with partial reductions (50%) in cytosolic MDH activity. This observation strongly suggests the operation of pyruvate–malate and, in particular, pyruvate–citrate cycling in adaptation to alcohol exposure. We propose that an understanding of the evolution of tolerance to alcohols will require a system-level approach, rather than a focus on single enzymes.
A Systematic Screen for Transcriptional Regulators of the Yeast Cell Cycle
Authors: White Michael A , Riles Linda , Cohen Barak A
Published: November 2008

Transcription factors play a key role in the regulation of cell cycle progression, yet many of the specific regulatory interactions that control cell cycle transcription are still unknown. To systematically identify new yeast cell cycle transcription factors, we used a quantitative flow cytometry assay to screen 268 transcription factor deletion strains for defects in cell cycle progression. Our results reveal that 20% of nonessential transcription factors have an impact on cell cycle progression, including several recently identified cyclin-dependent kinase (Cdk) targets, which have not previously been linked to cell cycle transcription. This expanded catalog of cell-cycle-associated transcription factors will be a valuable resource for decoding the transcriptional regulatory interactions that govern progression through the cell cycle. We conducted follow-up studies on Sfg1, a transcription factor with no previously known role in cell cycle progression. Deletion of Sfg1 retards cells in G1, and overexpression of Sfg1 delays cells in the G2/M phase. We find that Sfg1 represses early G1, Swi5/Ace2-regulated genes involved in mother–daughter cell separation. We also show that Sfg1, a known in vitro cyclin-dependent kinase target, is phosphorylated in vivo on conserved Cdk phosphorylation sites and that phosphorylation of Sfg1 is necessary for its role in promoting cell cycle progression. Overall, our work increases the number of transcription factors associated with cell cycle progression, strongly indicates that there are many more unexplored connections between the Cdk–cyclin oscillator and cell cycle transcription, and suggests a new mechanism for the regulation of cell separation during the M/G1 phase transition.
Identification of tyrosine 806 as a molecular determinant of RET kinase sensitivity to ZD6474
Authors: Carlomagno Francesca , Guida Teresa , Anaganti Suresh , Provitera Livia , Kjaer Svend , McDonald Neil Q , Ryan Anderson J , Santoro Massimo
Published: November 2008

ZD6474 (vandetanib, Zactima, Astra Zeneca) is an anilinoquinazoline used to target the receptor tyrosine kinase RET in familial and sporadic thyroid carcinoma (IC50: 100 nM). The aim of this study was to identify molecular determinants of RET sensitivity to ZD6474. Here, we show that mutation of RET tyrosine 806 to cysteine (Y806C) induced RET kinase resistance to ZD6474 (IC50: 933 nM). Y806 maps close to the gate-keeper position at the RET kinase nucleotide-binding pocket. Although tyrosine 806 is a RET auto-phosphorylation site, its substitution to phenylalanine (Y806F) did not markedly affect RET susceptibility to ZD6474 (IC50: 87 nM), suggesting that phosphorylation of Y806 is not required for compound binding. Accordingly, the introduction of a phosphomimetic residue (Y806E) also caused resistance to ZD6474, albeit of a lesser degree (IC50: 512 nM) than the cysteine mutation. Y806C/E RET mutants were also resistant to ZD6474 with respect to intracellular signalling and activation of an AP1-responsive promoter. We conclude that Y806 is a molecular determinant of RET sensitivity to ZD6474. Y806C is a natural RET mutation identified in a patient affected by multiple endocrine neoplasia type 2B. Based on its rare occurrence, it is unlikely that Y806C will be a frequent cause of refractoriness to ZD6474; however, it may be envisaged that mutations at this site can mediate secondary resistance formation in patients treated with the compound.
Controlling Gas Channeling and Altering it to a Kind of Natural Gas Lift in an Iranian Offshore Oil Field
Authors: Nezhad Mohsen Dabiri , Darani Hesam Sheikh
Published: November 2008

This paper examines and compares Natural and Artificial Gas Lift performance of one of the Iranian Offshore fields. Before the results of this study, gas channeling from the upper gas layer, a phenomenon which causes gas streams to pierce into some of the wellbores, was characterized as a negative effect which should be treated or repaired. On the other hand, regarding that this is a fractured under-saturated reservoir with an active aquifer mechanism, it was foreseen that applying immiscible gas and water injection in this reservoir in order to increase recovery factor are ineffective; and studies supported this idea. With respect to the growing amount of water production, need to further study Artificial Lift Methods was assumed essential. Considering operational conditions and abundance of excessive gas in this field, a gas lift system was designed and the optimum injection points with best recoveries were identified. However, reservoir simulation surprisingly demonstrated that when gas channeling from the upper gas layer is taken into account, oil production rates exhibit a significant increase. This could be interpreted as Natural Gas Lift.

In this paper, we indicate how accidental gas channeling in the wells of this reservoir has prompted oil production rate to raise. Results of well modeling by PROSPER software, considering different flow scenarios, were imported into reservoir simulator and final recoveries were observed during a certain time period. Conclusively, it is suggested that controlling gas channeling in these wells by employing Natural Gas Lift Technology would maintain oil production capacity. According to the results, total field oil recovery factor would be almost 4 percent more than natural depletion during 21 years and that would be the most economical, applicable and effective way to improve recovery factor in this reservoir.
Sowing and Flowering Delays Can Be an Efficient Strategy to Improve Coexistence of Genetically Modified and Conventional Maize
Authors: Palaudelmàs Montserrat , Melé Enric , Peñas Gisela , Pla Maria , Nadal Anna , Serra Joan , Salvia Jordi , Messeguer Joaquima
Published: November 2008

The coexistence between genetically modified (GM) and non‐GM maize (Zea mays L.) fields is subjected to regulation in several countries. A strategy to reduce cross‐pollination from GM to non‐GM fields was evaluated, on the basis of reducing the flowering coincidence by sowing at separate times. The trial included narrow plots in which transgenic maize was sown before, simultaneously, and after adjacent non‐GM maize. A three‐week delay between GM and non‐GM sowing dates resulted in flowering delays below 5 d for early sowings, but up to 10 to 15 d for late sowings. Cross‐pollination was monitored by xenia effect and validated by real‐time PCR. The combined effect of flowering delay and distance from the pollen source was evaluated. Cross‐pollination dramatically decreased with distance between pollen source and receptor. Flowering delay interacted with distance to the pollen donor source and further reduced GM pollen flow in all cases. Thus, it acted as a regulatory factor. A flowering delay of 92.9 growing degree units (GDU) (7 d in our experimental conditions) was enough to reduce the adventitious presence of GM kernels in non‐GM maize plots down to residual values. This study illustrates the possibility of improving coexistence through temporal separation of flowering dates on the basis of appropriate delays in sowing dates.
Preliminary Assessment of Genetic Diversity and Phenetic Relations for Section Lasiocarpa by Means of Heterologous SSR Markers
Authors: Torres A. F. , Arias A. S. , Arahana V. , Torres M. L.
Published: November 2008

Naranjilla (Solanum quitoense Lam.) is an Andean fruit crop with great economic prospects in global export markets. The conservation and improvement of this crop greatly depend on the quantification of its genetic variability and on finding alternative sources of diversity in the Lasiocarpa section. The main objective of this study was to evaluate the extent to which SSR primer pairs specifically designed for Solanum tuberosum L. could be used in genetic diversity and phenetic studies of S. quitoense and its wild relatives from the Lasiocarpa section. Thirteen nuclear SSR primer pairs, out of 48 tested, were successfully transferred. Seven of these primers produced a total of 25 alleles and an average polymorphic information content (PIC) value of 0.4030. The genetic similarity index (Jaccard) between all accessions analyzed was 0.46 (0.54 dissimilarity), a value expected to increase with a greater sample population and a greater array of SSR primer pairs. Our preliminary UPGMA cluster analysis displayed seven major clusters and reinforces previous claims regarding the phenetic relations of section Lasiocarpa. The most important similarities between our results and the results of previous studies lie in the potential exclusion of S. stagnale from this section and the close genetic relationship that exists between S. candidum and the Asian members of this plant group. Our findings open the possibility for the exploitation of cross‐species amplification as a source of SSR markers for this plant group; thus contributing toward current developments aimed at improving and preserving S. quitoense, a crop of great importance to the Andean region.
Spatial Variability of the Illinois Soil Nitrogen Test: Implications for Sampling in a Turfgrass System
Authors: Gardner D. S. , Horgan B. P. , Horvath B. J.
Published: November 2008

Nitrogen fertilization of turfgrass continues to be scrutinized due to environmental concerns. Practices that reduce fertilizer inputs without sacrificing turfgrass quality are needed, but a reliable test of N status in turfgrass is not currently available. The Illinois soil N test has been developed to predict crop response to applied N by measuring the amount of amino sugar N in the soil. Amino sugar N does not fluctuate as rapidly as other forms of N in soil. Our objective is to determine the spatial variation of amino sugar N in soil to determine sampling frequency requirements for use of the Illinois soil N test as a management tool on golf course fairways. Soil samples from 0 to 15, 15 to 30, and 30 to 45 cm were collected from golf course fairways in Minnesota and analyzed for amino sugar N concentration. Our data indicate that amino sugar N concentration decreases with depth but is not correlated to the concentration in the 0 to 15 cm layer. Amino sugar N concentrations measured on the four sampled fairways varied, but the spatial correlation present would allow for traditional soil sampling techniques to be used to assess the soil amino sugar N concentration within an area such as a golf course fairway.
Jointed Goatgrass Management with Imazamox‐Resistant Cultivars in a Winter Wheat–Fallow Rotation
Authors: Kniss Andrew R. , Lyon Drew J. , Miller Stephen D.
Published: November 2008

Jointed goatgrass (Aegilops cylindrica Host) is an economically important weed in winter wheat (Triticum aestivum L.)–fallow production regions of the United States. Few options exist for management of jointed goatgrass in winter wheat due to the close genetic relationship between the two species. This research evaluated use of imazamox herbicide (2‐[(RS)‐4‐isopropyl‐4‐methyl‐5‐oxo‐2‐imidazolin‐2‐yl]‐5‐methoxymethylnicotinic acid) in an imazamox‐resistant (IR) winter wheat–fallow rotation over 6 yr when grown continuously or in rotation with a conventional winter wheat cultivar. The objectives of this study were to compare use patterns of IR technology in winter wheat with respect to jointed goatgrass density and wheat grain contamination over three crop years in a winter wheat–fallow system and to monitor jointed goatgrass and jointed goatgrass × wheat hybrid populations for resistance to imazamox. The IR treatment resulted in reduced jointed goatgrass density compared to conventional treatments in 5 out of 6 yr. Reductions in jointed goatgrass tiller density resulting from use of imazamox in IR winter wheat were evident in a subsequent crop year at each of two experimental sites. No IR jointed goatgrass plants nor viable jointed goatgrass × wheat hybrid plants were found. In a winter wheat–fallow rotation, IR technology can effectively manage jointed goatgrass populations and reduce jointed goatgrass contamination of grain. Use of the technology every other crop year, or two out of every three crop years, will provide management benefits in subsequent years.
Predicted Genetic Gain and Inbreeding Depression with General Inbreeding Levels in Selection Candidates and Offspring
Authors: Edwards Jode W.
Published: November 2008

Methods for predicting response to selection in noninbred populations for individuals and family‐based selection methods have been very well developed. However, theory to predict improvement of inbred lines derived from a recombined population, as well the predicted change in inbreeding depression rate, has not been developed. Prediction equations for general levels of inbreeding in both selection candidates and recombined offspring of selected parents for intrapopulation selection methods were developed. All common methods of individual, half‐sib, and self‐progeny selection were predicted to change inbreeding depression rates in a population if the covariance parameters D1 and D2* were nonzero. However, the change in inbreeding depression rate was unaffected by additive genetic variance. It was further established that outbred selection in some maize (Zea mays L.) populations may be expected to increase inbreeding depression based on published estimates of the covariance parameter D1.
Diversity and Relatedness of Common Carpetgrass Germplasm
Authors: Greene Nicholas V. , Kenworthy Kevin E. , Quesenberry Kenneth H. , Unruh J. Bryan , Sartain Jerry B.
Published: November 2008

Common carpetgrass (Axonopus fissifolius Raddi) is a stoloniferous, sod‐forming species used sparingly as a turfgrass. No information is available regarding the relationships between germplasm accessions of this species. Accordingly, the initial objective of this study was to evaluate the relatedness of common carpetgrass germplasm for morphological and turfgrass performance traits. This was accomplished using principal component and cluster analysis. Resulting principal components were separated into related traits that influenced plant architecture, aesthetic appeal, and inflorescence characteristics. The secondary objective was to identify if collection location impacted genotype performance. This was completed by arranging genotypes into groups on the basis of their geographic origin within the collection area and subsequently analyzing the groups to determine if collection location impacted growth and performance. Differences were found for winter color, establishment, and seedhead density between the SE group and other groups (SW, NE, and NW) which were not different from each other. Groups refer to regions; specifically, SE represents south of 31° N latitude and east of 86° W longitude, SW represents south of 31° N latitude and west of 86° W longitude, NE represents north of 31° N latitude and east of 86° W longitude, and NW represents north of 31° N latitude and west of 86° W longitude.
Changes in Isoflavone Concentration with 58 Years of Genetic Improvement of Short‐Season Soybean Cultivars in Canada
Authors: Morrison M. J. , Cober E. R. , Saleem M. F. , McLaughlin N. B. , Frégeau‐Reid J. , Ma B. L. , Yan W. , Woodrow L.
Published: November 2008

Soybean [Glycine max (L.) Merr.] seeds contain a high concentration of the isoflavones daidzein and genistein, which are considered to be compounds beneficial to human health. Our objective was to determine the influence of breeding and selection for yield on the isoflavone concentration of short‐season cultivars. A collection of 14 historical cultivars released from 1934 to 1992 was grown at Ottawa for 12 yr under identical cultural conditions. Seed samples, taken at harvest, were examined using near‐infrared reflectance in conjunction with traditional chemical methods to measure the concentration of daidzein, genistein, and total isoflavones (TIF). A linear regression equation developed based on the changes across time of cultivar release was used to determine the improvement rates for various soybean parameters. Across the 58 yr of breeding history, yield and oil concentration increased by 0.43 and 0.24% per year, respectively, while protein concentration decreased by 0.15% per year. Across the same time period daidzein, genistein, and TIF increased by 1.04, 1.47, and 0.98% per year, respectively. Moderate broad sense heritabilities of 43, 45, and 44% were calculated for the aforementioned isoflavones. Genotype main effects + genotype × environment interaction biplots revealed that recent cultivars with high isoflavone concentration were more prone to environmental influence than older cultivars. In the short‐season region, plant breeders should be aware that selecting for higher yield may indirectly select for higher isoflavone concentration.
Inheritance and Genetic Mapping of Resistance to Pythium Damping‐Off Caused by Pythium aphanidermatum in ‘Archer’ Soybean
Authors: Rosso M. Luciana , Rupe John C. , Chen Pengyin , Mozzoni Leandro A.
Published: November 2008

Pythium damping‐off and root rot of soybean [Glycine max (L.) Merr.] causes poor stands and consequently reduces yields. Resistance to seedling diseases caused by Pythium spp. was reported in the soybean cultivar Archer and was described to be associated with the Rps1k gene for resistance to Phytophthora sojae. To characterize the inheritance of Pythium damping‐off resistance in Archer and to determine if this resistance is linked to Rps1k, the cross of Archer × ‘Hutcheson’ (susceptible parent) was made and F2:4 lines generated. Parents and F2:4 lines were screened with Pythium aphanidermatum using a hypocotyl inoculation technique. Five days after inoculation, plant survival was scored. The F2:4 lines and parents were also inoculated with race 7 of P. sojae to assess the association of resistance to Pythium spp. with the Rps1k gene. Data from the F2:4 lines fit the model for a single dominant gene in Archer that confers resistance to P. aphanidermatum. The genetic linkage test showed that resistance to P. aphanidermatum was independent of the Rps1k gene in Archer. To identify the genomic location of the Pythium resistance gene, F2:4 lines were screened with simple sequence repeat (SSR) markers from all the soybean molecular linkage groups (MLGs). Two SSR markers, Satt510 and Satt114 on MLG F, which were polymorphic between the parents and the resistant and susceptible bulks, were shown to be associated with Pythium resistance. The Pythium resistance gene, named Rpa1, was located 10.6 cM from Satt510 and 26.6 cM from Satt114.
Optimization of the Marker‐based Procedures for Pyramiding Genes from Multiple Donor Lines: III. Multiple‐Gene Assemblage Using Background Marker Selection
Authors: Ishii T. , Hayashi T. , Yonezawa K.
Published: November 2008

Constructing high‐degree gene‐pyramided lines has important practical implications; such lines could be used for multiple purposes, for example, as a high‐powered breeding stock line, a material line for characterizing multigene interactions, or a market variety as it stands. Effectiveness of two typical marker‐based schemes for constructing such lines, named AF (gene assemblage first) and BF (backcross first), is discussed. In AF, target genes of all donor parents are assembled onto the genome of a plant first, followed by backcross generations for the recovery of recipient parent genome. In BF, backcross is performed first separately for each donor, followed by generations of crossing for the assemblage of target genes. Our stochastic calculations show that BF is superior to AF when molecular selection is used for both target genes and background markers; with the same number of generations (time) and cost of genotyping, BF produces a much higher recovery of recurrent parent genome than AF. The superiority of BF weakens somewhat when target genes are selected by phenotype; AF is superior when assembling three or more unlinked target genes, or could be a choice of the breeder when assembling three or more linked genes. Otherwise, BF is superior. To minimize cost, genotyping and selection for background markers should be performed stepwise in each generation, that is, in three or four stages starting from markers closely linked with target genes to unlinked ones.
Double Exponential Model Describes Decay of Hybrid Bermudagrass Thatch
Authors: Berndt William L.
Published: November 2008

Empirical modeling helps understand decay processes. The objective of this research was to find a suitable model, and then use it to describe decay of thatch from hybrid bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt‐Davy]. The carbon dioxide–carbon released from ‘Tifdwarf’ and ‘Tifeagle’, each 24 h over 20 d, was plotted as percent C remaining vs. time. Four empirical models were fit to these data to determine which one best minimized residual sum of squares. The model best meeting this condition was the four‐parameter double exponential model. Of the models tested, it was the only one to pass all tests for normally distributed population, constant variance, and independence of residuals. Fitting this model to percent C remaining data identified two C pools for each cultivar, a fast pool and a slow pool, with differing sizes and rate constants. Fast‐pool turnover times were similar. Slow‐pool turnover times differed, with Tifdwarf decaying faster than Tifeagle, which may have been a function of Tifeagle having a higher stolon mass with more lignin and a wider C:N. When data were corrected for microbial growth efficiency, slow‐pool turnover times decreased. This implied cultural practices that increase microbial growth efficiency may help convert slow pool into biomass, reduce slow‐pool turnover times, and ultimately enhance the decay of thatch.
Genetic Improvement of Sorghum as a Biofuel Feedstock: II. QTL for Stem and Leaf Structural Carbohydrates
Authors: Murray Seth C. , Rooney William L. , Mitchell Sharon E. , Sharma Arun , Klein Patricia E. , Mullet John E. , Kresovich Stephen
Published: November 2008

Digestion and fermentation of lignocellulosic biomass (i.e., structural carbohydrates) are predicted to deliver higher yields of energy per hectare than sugar and starch (nonstructural carbohydrates), yet little research on genetic variation in crop feedstock biomass traits has been conducted. We investigated the genetic basis of leaf and stem biomass yield and composition in a population derived from a high‐biomass sweet sorghum, ‘Rio’, and a grain sorghum inbred line, ‘BTx623’, and compared these results with those from analyses of grain and stem sugar traits that we reported previously. Thirty‐one traits were evaluated and a total of 110 quantitative trait loci (QTL) were identified across three locations. Many QTL for structural and nonstructural carbohydrate yields colocalized with loci for height, flowering time, and stand density–tillering. Quantitative trait loci for composition had little colocalization across tissues and environments. Separate genetic control for leaf and stem structural carbohydrate composition was identified, as well as separate genetic control of protein accumulation in leaf, stem, and grain. To maximize energy yields from grain and dedicated biomass sorghums, results suggest yield traits should be targeted for improvement before composition traits.
Mutations in a Δ9–Stearoyl‐ACP‐Desaturase Gene Are Associated with Enhanced Stearic Acid Levels in Soybean Seeds
Authors: Zhang Ping , Burton Joseph W. , Upchurch Robert G. , Whittle Edward , Shanklin John , Dewey Ralph E.
Published: November 2008

Stearic acid (18:0) is typically a minor component of soybean [Glycine max (L.) Merr.] oil, accounting for only 2 to 4% of the total fatty acid content. Increasing stearic acid levels of soybean oil would lead to enhanced oxidative stability, potentially reducing the need for hydrogenation, a process leading to the formation of undesirable trans fatty acids. Although mutagenesis strategies have been successful in developing soybean germplasm with elevated 18:0 levels in the seed oil, the specific gene mutations responsible for this phenotype were not known. We report a newly identified soybean gene, designated SACPD‐C, that encodes a unique isoform of Δ9–stearoyl‐ACP‐desaturase, the enzyme responsible for converting stearic acid to oleic acid (18:1). High levels of SACPD‐C transcript were only detected in developing seed tissue, suggesting that the encoded desaturase functions to enhance oleic acid biosynthetic capacity as the immature seed is actively engaged in triacylglycerol production and storage. The participation of SACPD‐C in storage triacylglycerol synthesis is further supported by the observation of mutations in this gene in two independent sources of elevated 18:0 soybean germplasm, A6 (30% 18:0) and FAM94‐41 (9% 18:0). A molecular marker diagnostic for the FAM94‐41 SACPD‐C gene mutation strictly associates with the elevated 18:0 phenotype in a segregating population, and could thus serve as a useful tool in the development of cultivars with oils possessing enhanced oxidative stability.
Response of Native Southeastern U.S. Legumes to Root‐Knot Nematodes
Authors: Quesenberry Kenneth H. , Dampier Judith M. , Crow Billy , Dickson Donald W.
Published: November 2008

Identification of forage legumes well adapted to the southeastern United States is complicated by climatic, soil, and biotic factors. Among the pests that impact forage legume persistence are root‐knot nematodes (RKNs) (Meloidogyne spp.). We hypothesized that legumes native to the region should have higher levels of resistance to RKN species that are common in this region due to long‐term natural selection pressure. The objective of this research was to evaluate the response of 10 southeastern U.S. native legumes to M. arenaria (Neal) Chitwood race 1, M. incognita (Kofoid and White) Chitwood race 3, and M. javanica (Treub) Chitwood. Legumes were grown in Cone‐tainers in a greenhouse for 3 wk, inoculated with a given RKN isolate, and after an additional 9 wk were uprooted and evaluated for root galling and nematode egg mass production responses. The level of root galling and egg mass production varied among native legumes, but in general was lower than previously observed on introduced legumes. Desmodium paniculatum (L.) DC., Galactia regularis (L.) Britton et al., and Centrosema virginianum (L.) Benth. varied among the three RKN species in their root galling and egg mass production responses. The accession of D. incanum DC. used was immune to all three RKN isolates, and could be a potential source of RKN resistance genes. The perennial native legumes evaluated all had either a fleshy taproot or a strong rhizome system.
Physiological Determinants for Pod Yield of Peanut Lines
Authors: Phakamas N. , Patanothai A. , Jogloy S. , Pannangpetch K. , Hoogenboom G.
Published: November 2008

The number of pods per unit area is an important component of pod yield of peanut. The goals of this study were to determine the relationships of (i) pod yield with number of pods per unit area and weight per pod and (ii) number of pods per unit area with crop growth rate (CGR) and duration during the different developmental stages. Fifteen peanut lines were tested at Khon Kaen University in Northeast Thailand during the 2002 and 2003 rainy and the 2003 and 2004 dry seasons. Data were recorded on developmental stages, biomass, pod yield, and yield components. The CGRs were calculated for different developmental periods. Results showed a positive linear relationship between pod yield and number of pods per unit area across genotypes and seasons (R2 = 0.69; P > F < 0.0001), but no relationship was observed between pod yield and weight per pod (R2 = 0.001; P > F = 0.85). A significant relationship between number of pods per unit area and CGR among the test genotypes was found only during the period from R6 to R7 (R2 = 0.44; P > F = 0.007), and the same relationship across seasons was significant (R2 = 0.45; P > F < 0.001) only during the period from planting to R4. These results indicate that number of pods per unit area is the major determinant for pod‐yield differences among peanut lines, and that the differences among lines for this trait are influenced by CGR during the period from R6 to R7.
Effect of Dwarfing Rht Genes on Fusarium Head Blight Resistance in Two Sets of Near‐Isogenic Lines of Wheat and Check Cultivars
Authors: Miedaner T. , Voss H.‐H.
Published: November 2008

Reduced height (Rht) genes are used in wheat (Triticum aestivum L.) breeding throughout the world. Fusarium head blight (FHB) is one of the most destructive wheat diseases caused by Fusarium graminearum (Schwabe) and F. culmorum (W.G. Sm.) Sacc. Objectives of this study were to analyze the effects of (i) specific Rht dwarfing genes on FHB reaction using two sets of near‐isogenic lines (NILs) and (ii) genetic background and environment on FHB reaction. We inoculated NILs carrying Rht‐B1b, Rht‐B1d, Rht‐D1b, Rht8c, and Rht‐D1b+Rht8c in the background of the British winter wheat cultivar Mercia possessing medium height and moderate resistance, and NILs carrying Rht‐B1b, Rht‐B1c, Rht‐D1b and Rht‐B1b+Rht‐D1b in the background of the rather tall, generally more resistant British cultivar Maris Huntsman, as well as three German check cultivars (‘Toras’, ‘Certo’, ‘Travix’) carrying the Rht‐D1b allele. Entries were tested in eight (Mercia) and four (Maris Huntsman) environments, respectively, by inoculation with F. culmorum In the Mercia data set, Rht‐B1d and Rht‐D1b significantly increased mean FHB rating by 35 and 52%, respectively. Rht‐B1b and Rht8c increased FHB rating only by 19%, being not significantly different to the wild‐type line (rht). Rht8c affected heading date due to its linkage with the photoperiod insensitive Ppd1 allele. In the Maris Huntsman data set, FHB rating was increased by 22 to 83%, but only the very short Rht‐B1c and Rht‐B1b+Rht‐D1b lines showed significance. Although the mutant Rht alleles increased FHB susceptibility, the checks show that these negative effects can be largely counteracted by a more resistant genetic background.
Heterosis in Switchgrass: Biomass Yield in Swards
Authors: Vogel Kenneth P. , Mitchell Rob B.
Published: November 2008

Improving the biomass yield of switchgrass (Panicum virgatum L.) will improve its utility as a dedicated energy crop by increasing both its net and total energy yield per hectare. In a previous space‐transplanted study, midparent heterosis for biomass yield was reported for population and specific F1 hybrids of the lowland‐tetraploid cultivar Kanlow and the upland‐tetraploid cultivar Summer. These two cultivars were proposed to be two different heterotic groups. The objective of this study was to determine the extent of heterosis for biomass yield in reciprocal Kanlow (K) and Summer (S) F1 population hybrids grown in simulated swards and to determine the effect of advance in generation on biomass yield. Parent populations and their F1, F2, and F3 population hybrids were grown in transplanted sward plots located near Mead, NE, for a three‐year period. Plant density in the simulated swards was equivalent to acceptable stands in seeded plots. Plots were not harvested the establishment year to enable them to become fully established. Biomass yields were determined for the following two years. There was significant high‐parent heterosis of 30 to 38% (P ≤ 0.01) for biomass yield for both the K × S F1 and S × K F1 hybrid populations. Heterosis for biomass yield declined with advance in generation. Heterosis for biomass yield in switchgrass may need the competitive conditions of swards to be fully expressed. Additional trials of specific hybrids established from seed are needed to further verify these conclusions. These results do provide ample justification for additional research to develop switchgrass population and specific hybrids.