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Plant waxes and staygreen are distinct phenotypic traits that have been independently implicated in heat and drought tolerance among grasses. The association between these two traits has not been fully explored, which makes the exploitation of synergy between them difficult. This study assessed the association between QTL regulating the staygreen (Stg) trait in sorghum and those regulating epicuticular wax load (WL) and associated canopy temperature depression (TD). Using a recombinant inbred line (RIL) population derived from Tx642 and Tx7000, phenotypic data were collected in three replicated field trials and one greenhouse trial. High absolute TD generally corresponded to high WL. The r2 of TD against WL was highest under non-stress conditions in the greenhouse while it was much larger in the cooler and irrigated field conditions compared to hotter, drier field trials. The genetic correlations between the two traits also followed this pattern. Composite interval mapping identified a total of 28 QTL, 15 of which had significant overlaps between different traits. Most of the wax QTL were associated with pre-anthesis drought tolerant Tx7000. However, one QTL for WL overlapped with a QTL for staygreen (Stg2) and was represented by a single, isolated marker near the centromeric region on the short arm of SBI-01. The marker is identified by a Cis-acting regulatory module and is part of a 2-kb multifunctional motif-rich region which includes core promoter and enhancer regions and transcription elements, including a drought-responsive MYB binding site. We suggest that this QTL may be pleiotropic for important stress tolerance mechanisms regulating both staygreen and leaf wax in sorghum. [ABSTRACT FROM AUTHOR]

There is a pressing need for biomarkers and outcomes that can be used across disease stages in Duchenne muscular dystrophy (DMD), to facilitate the inclusion of a wider range of participants in clinical trials and to improve our understanding of the natural history of DMD. Quantitative magnetic resonance imaging (qMRI) and spectroscopy (MRS) biomarkers show considerable promise in both the legs and forearms of individuals with DMD, but have not yet been examined in functionally important proximal upper extremity muscles such as the biceps brachii and deltoid. The primary objective of this study was to examine the feasibility of implementing qMRI and MRS biomarkers in the proximal upper extremity musculature, and the secondary objective was to examine the relationship between MR measures of arm muscle pathology and upper extremity functional endpoints. Biomarkers included MRS and MRI measures of fat fraction and transverse relaxation time ( T ). The MR exam was well tolerated in both ambulatory and non-ambulatory boys. qMR biomarkers differentiated affected and unaffected participants and correlated strongly with upper extremity function ( r = 0.91 for biceps brachii T versus performance of upper limb score). These qMR outcome measures could be highly beneficial to the neuromuscular disease community, allowing measurement of the quality of functionally important muscles across disease stages to understand the natural history of DMD and particularly to broaden the opportunity for clinical trial participation. [ABSTRACT FROM AUTHOR]

Hyperphagia and obesity have been reported following damage to the hypothalamus in humans. Other brain sites are also postulated to be involved in the control of food intake and body weight regulation, such as the amygdala and brainstem. The brainstem, however, is thought to primarily integrate short-term meal-related signals but not affect long-term alterations in body weight, which is controlled by higher centers. The objective of this study was to identify structural pathways damaged in a patient with a brainstem cavernoma who experienced sudden onset of hyperphagia and >50 kg weight gain in <1 year following surgical drainage via a midline suboccipital craniotomy. Diffusion tensor imaging revealed loss of nerve fiber connections between her brainstem, hypothalamus and higher brain centers with preservation of motor tracks. Imaging and endocrine testing confirmed normal hypothalamic structure and function. Gastric bypass surgery restored normal appetite and body weight to baseline. This is the first report of 'brainstem obesity' and adds to the brain regions that can determine the long-term body weight set point in humans. [ABSTRACT FROM AUTHOR]

Amplified fragment length polymorphism (AFLP) based genetic diversity was analyzed for 232 Colletotrichum sublineolum isolates collected between 2002 and 2004 from three geographically distinct regions of Texas, and from Arkansas, Georgia, and Puerto Rico. Results revealed significant levels of polymorphism (59%) among the isolates. Even so, genetic similarity between isolates was high, ranging from 0.78 to 1.00. Clustering of similar isolates did not correlate with either geographic origin or year of collection. Pathotypes of 20 of the isolates were determined using 14 sorghum lines previously used in Brazil and the United States and 4 from Sudan. Seventeen new pathotypes were established from the 18 isolates that gave uniform and consistent reactions on all host differentials over 2 years of greenhouse testing. Differentials BTx378 and QL3 were resistant to all isolates while BTx623 and TAM428 were universally susceptible both years. Each of these lines had shown differential responses in prior studies indicating that the pathogen population has sufficient diversity to adapt rapidly to changes in resistant host lines deployed. When the 2-step pathotype classification scheme was used, the 18 isolates examined in this study were placed in four pathotype groups (A, C, D and G), which would further then be separated into ten distinct pathotypes. Common sets of differentials and a standardized nomenclature will allow for comparison to be made among pathotypes of C. sublineolum detected from different regions and also could help direct planting of appropriate sorghum lines and aid in the development of more durable forms of resistance. [ABSTRACT FROM AUTHOR]

Anthracnose, caused by the fungus Colletotrichum sublineolum is one of the most destructive diseases of sorghum and has been reported in most areas where the crop is grown. Several control strategies have been developed but host plant resistance has been regarded as the most effective strategy for disease control. Here, we describe the search for molecular markers that co-segregate with Cg1, a dominant gene for resistance originally identified in cultivar SC748-5. To identify molecular markers linked with the Cg1 locus, F2:3 plants derived from a cross to susceptible cultivar BTx623 were analyzed with 98 AFLP primer combinations. BTx623 was chosen as the susceptible parent because it is also one on the parents used in creating RFLP and AFLP maps and BAC libraries for sorghum. Four AFLP markers that cosegregate with disease resistance were identified, of which Xtxa6227 mapped within 1.8 cM of the anthracnose resistance locus and all four AFLP markers have been previously mapped to the end of sorghum linkage group LG-05. Sequence scanning of BAC clones spanning this chromosome led to the discovery that Xtxp549, a polymorphic simple sequence repeat (SSR) marker, mapped within 3.6 cM of the anthracnose resistance locus. To examine the efficacy of Xtxa6227 and Xtxp549 for marker-assisted selection, 13 breeding lines derived from crosses with sorghum line SC748-5 were genotyped. In 12 of the 13 lines the Xtxa6227 and Xtxp549 polymorphism associated with the Cg1 locus was still present, suggesting that Xtxp549 and Xtxa6227 could be useful for marker-assisted selection and for pyramiding of Cg1 with other genes conferring resistance to C. sublineolum in sorghum. [ABSTRACT FROM AUTHOR]

The grass inflorescence is the primary food source for humanity, and has been repeatedly shaped by human selection during the domestication of different cereal crops. Of all major cultivated cereals, sorghum [ Sorghum bicolor (L.) Moench] shows the most striking variation in inflorescence architecture traits such as branch number and branch length, but the genetic basis of this variation is little understood. To study the inheritance of inflorescence architecture in sorghum, 119 recombinant inbred lines from an elite by exotic cross were grown in three environments and measured for 15 traits, including primary, secondary, and tertiary inflorescence branching. Eight characterized genes that are known to control inflorescence architecture in maize ( Zea mays L.) and other grasses were mapped in sorghum. Two of these candidate genes, Dw3 and the sorghum ortholog of ramosa2, co-localized precisely with QTL of large effect for relevant traits. These results demonstrate the feasibility of using genomic and mutant resources from maize and rice ( Oryza sativa L.) to investigate the inheritance of complex traits in related cereals. [ABSTRACT FROM AUTHOR]

With an aim to clone the sorghum fertility restorer gene Rf1, a high-resolution genetic and physical map of the locus was constructed. The Rf1 locus was resolved to a 32-kb region spanning four open reading frames: a plasma membrane Ca2+-ATPase, a cyclin D-1, an unknown protein, and a pentatricopeptide repeat ( PPR13) gene family member. An ~19-kb region spanning the cyclin D-1 and unknown protein genes was completely conserved between sterile and fertile plants as was the sequence spanning the coding region of the Ca2+-ATPase. In contrast, 19 sequence polymorphisms were located in an ~7-kb region spanning PPR13, and all markers cosegregated with the fertility restoration phenotype. PPR13 was predicted to encode a mitochondrial-targeted protein containing a single exon with 14 PPR repeats, and the protein is classified as an E-type PPR subfamily member. To permit sequence-based comparison of the sorghum and rice genomes in the Rf1 region, 0.53 Mb of sorghum chromosome 8 was sequenced and compared to the colinear region of rice chromosome 12. Genome comparison revealed a mosaic pattern of colinearity with an ~275-kb gene-poor region with little gene conservation and an adjacent, ~245-kb gene-rice region that is more highly conserved between rice and sorghum. Despite being located in a region of high gene conservation, sorghum PPR13 was not located in a colinear position on rice chromosome 12. The present results suggest that sorghum PPR13 represents a potential candidate for the sorghum Rf1 gene, and its presence in the sorghum genome indicates a single gene transposition event subsequent to the divergence of rice and sorghum ancestors. [ABSTRACT FROM AUTHOR]

We report the molecular mapping of a gene for pollen fertility in A1 (milo) type cytoplasm of sorghum using AFLP and SSR marker analysis. DNA from an F2 population comprised of 84 individuals was screened with AFLP genetic markers to detect polymorphic DNAs linked to fertility restoration. Fifteen AFLP markers were linked to fertility restoration from the initial screening with 49 unique AFLP primer combinations (+3/+3 selective bases). As many of these AFLP markers had been previously mapped to a high-density genetic map of sorghum, the target gene (rf1) could be mapped to linkage group H. Confirmation of the map location of rf1 was obtained by demonstrating that additional linkage group-H markers (SSR, STS, AFLP) were linked to fertility restoration. The closest marker, AFLP Xtxa2582, mapped within 2.4 cM of the target loci while two SSRs, Xtxp18 and Xtxp250, flanked the rf1 locus at 12 cM and 10.8 cM, respectively. The availability of molecular markers will facilitate the selection of pollen fertility restoration in sorghum inbred-line development and provide the foundation for map-based gene isolation. [ABSTRACT FROM AUTHOR]

Grain-mould is a major problem in grain sorghum utilization as mouldy grain has a reduced quality due to the deterioration of the endosperm and reduced embryo viability. Here, our objective was to use genome mapping to improve knowledge of genetic variation and co-variation for grain-mould incidence and other inter-related agronomic traits. Grain-mould incidence, kernel-milling hardness, grain density, plant height, panicle peduncle length, foliar-disease incidence, and plant color were measured on 125 F5 genotypes derived from a cross of Sureño and RTx430. Quantitative trait loci were detected by means of 130 mapped markers (44 microsatellites, 85 AFLPs, one morphological-trait locus) distributed among ten linkage groups covering 970 cM. One to five QTLs affected each trait, with the exception of grain density for which no QTLs were detected. Grain-mould incidence was affected by five QTLs each accounting for between 10 and 23% of the phenotypic variance. The effects and relative positions of QTLs for grain-mould incidence were in accordance with the QTL distribution of several inter-related agronomic traits (e.g., plant height, peduncle length) and with the correlation between these phenotypic traits and grain-mould incidence. The detection of QTLs for grain-mould incidence was dependent on the environment, which is consistent with heritibility estimates that show strong environmental and genotype × environment effects. Several genomic regions affected multiple traits including one region that affected grain-mould incidence, plant height, panicle peduncle length, and grain-milling hardness, and a second region that influenced grain-mould (in four environments) and plant height. One genomic region, which harbors loci for plant color, influenced the severity of foliar disease symptoms and the incidence of grain-mould in one environment. Collectively QTLs detected in the present population explained between 10% and 55% of the phenotypic variance observed for a given trait. [ABSTRACT FROM AUTHOR]

The use of RFLP markers, together with a partial set of monosomics available in Avena byzantina cv Kanota, has enabled us to identify putative homoeologous chromosome sets in hexaploid Avena species (2n = 6x = 42, AACCDD). We first identified probes producing distinct three-band patterns on Southern blots that possibly reflect orthologous loci of the three genomes present in the hexaploid. Using monosomic analysis, 51 different restriction fragments that hybridized to 26 probes were localized to 12 different chromosomes for which monosomic stocks were available. These DNA restriction fragments were localized to specific monosomics using image analysis to quantify band intensity relative to other bands in the same lane. From these data, we have tentatively identified two complete homoeologous sets of three chromosomes each and two partial sets of two of the three chromosomes. The results indicate that RFLP dosage analysis is useful in the characterization of homoeologous chromosomes in hexaploid oat where nullisomics for many of the chromosomes are not available. Mention of a trademark or proprietary product does not constitute a guarantee or warranty by the USDA-ARS or the University of Minnesota and does not imply approval over other products that also may be suitable [ABSTRACT FROM AUTHOR]

Several lines of evidence suggest that the dopamine D[sub 3] receptor is involved in the pathophysiology of schizophrenia. The D[sub 3] receptor gene (DRD3) contains a polymorphism resulting in a serine-glycine substitution in the N-terminus of the receptor. Shaikh and colleagues have reported a significant association between the DRD3 Ser[sub 9] allele and the Ser[sub 9]/Ser[sub 9] genotype with schizophrenia in 133 Caucasians. In a meta-analysis of previous studies, Ser[sub 9] and the Ser[sub 9]/Ser[sub 9] genotype were found to be significantly associated with schizophrenia, although these investigators could not confirm reports of excess homozygosity at this locus in schizophrenia. These authors also report that, in an unblinded study, the Ser9/Ser[sub 9] genotype was more frequent in patients who did not respond to clozapine. These data represent the most comprehensive examination of DRD3 Ser[sub 9]Gly in schizophrenia to date. We have therefore determined DRD3 Ser[sub 9]Gly genotypes in 58 patients with schizophrenia and in their parents. Moreover, we have genotyped 68 schizophrenics participating in double-blind clozapine trials. We do not find that Ser[sub 9] is preferentially transmitted in schizophrenia, cannot confirm excess DRD3 homozygosity in schizophrenia, and do not replicate the association between DRD3 and clozapine response. These data suggest that allelic variation in DRD3 may not play a role in the pathophysiology of schizophrenia or in clozapine response. [ABSTRACT FROM AUTHOR]

The kinetics of a single oral dose of mefloquine given either alone or with tetracycline has been studied in 20 healthy Thai male volunteers. There was a significantly higher maximum whole blood mefloquine concentration after coadministration with tetracycline (1600 vs 1160 ng · ml), as well as a significantly reduced terminal half-life (14.4 vs 19.3 days), mean residence time (11.9 vs 16.0 days) and volume of distribution at steady state (13.3 vs 19.91 · kg). Although there was no significant change in the AUC from zero time to infinity, the AUC from zero time to 7 days was significantly increased by tetracycline (6.18 vs 4.76 μg · ml · day). The changes in mefloquine disposition after tetracycline treatment are probably due to a reduction in enterohepatic recycling. The initial increase in mefloquine AUC without an apparent increase in side-effects suggests that this combination may have a place in the treatment of multi-drug resistant falciparum malaria. [ABSTRACT FROM AUTHOR]

A correction to the article "Fertility restorer locus Rf1 sorghum (Sorghum bicolor L.) encodes a pentatricopeptide repeat protein not present in the colinear region of rice chromosome 12 that was published in the November 2005 issue is presented.