1,792 research outputs found

    Effect of Planting Date on Maize Starch Thermal Properties.

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    Starches isolated from kernels of two maize (Zea mays L.) inbreds and their F1 progeny, grown after four planting dates, were evaluated for differences in thermal properties. Differential scanning calorimetry (DSC) was used to compare onset (To) and peak (Tp) temperature, range (Rn), and total enthalpy ((Delta)H) values of gelatinization. Amylose content (%AM) of samples was determined colorimetrically, and image analysis was used to determine average diameters of granules. Significant (P less than or equal to 0.05) increases for Tp and (Delta)H were observed with later planting dates. Significant genotypic differences also were seen for To, Tp, and (Delta)H. Later planting dates had no effect on %AM or starch granule size. Genotypes ranked similarly for %AM across each environment, and no differences were observed for average granule diameter. The presence of environmental effects on thermal properties of the starch suggests that if small differences (1-2 C or less than 0.2-0.3 cal/g) are to be identified among nonmutant genotypes, growing conditions may need to be controlled

    Properties of Sugary-2 Maize Starch: Influence of Exotic Background.

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    Genetic modifiers of maize (Zea mays L.) starch thermal properties were examined by differential scanning calorimetry (DSC). Sugary- 2 (su2) kernels from segregating ears were identified based on textural appearance of starches following crosses between an exotic maize accession with the inbred OH43 homozygous for the su2 allele (OH43 su2). Two exotic maize accessions, PI213768 and PI451692, were used. Germs retained from su2 kernels were used to produce an F2 population of su2 plants containing 50% exotic germ plasm. With few exceptions, F2 ears from the populations were homozygous for the su2 allele. Significant (P less than or equal to 0.05) differences were seen between the exotic populations and OH43 su2 for gelatinization onset temperature (To), range (RN), enthalpy (deltaH), and retrogradation (%R). The number of DSC values with significant within-population variations was greater among F2 ears within the exotic populations than among ears within the inbred line OH43 su2. Standard deviations for DSC values were consistently greater for exotic su2 populations than for those of OH43 su2. Also, the population PI213768 su2 differed greatly from OH43 su2 for mean values of To, RN, deltaH, and %R (52.8 C, 13.4 C, 1.5 cal/g, and 34.5%, respectively) when compared to those of OH43 su2 (54.6 C, 10.6 C, 1.3 cal/g, and 29%, respectively). Results from this study indicate that examining the texture of starches from single kernels may be used to identify and develop populations homozygous for the su2 allele. In addition, the increased variability for DSC values within populations containing 50% exotic germ plasm suggest that genetic modifiers might be used to alter thermal properties and, possibly, functional properties of su2 starch

    Analysis of Canis mitochondrial DNA demonstrates high concordance between the control region and ATPase genes

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    BACKGROUND: Phylogenetic studies of wild Canis species have relied heavily on the mitochondrial DNA control region (mtDNA CR) to infer species relationships and evolutionary lineages. Previous analyses of the CR provided evidence for a North American evolved eastern wolf (C. lycaon), that is more closely related to red wolves (C. rufus) and coyotes (C. latrans) than grey wolves (C. lupus). Eastern wolf origins, however, continue to be questioned. Therefore, we analyzed mtDNA from 89 wolves and coyotes across North America and Eurasia at 347 base pairs (bp) of the CR and 1067 bp that included the ATPase6 and ATPase8 genes. Phylogenies and divergence estimates were used to clarify the evolutionary history of eastern wolves, and regional comparisons of nonsynonomous to synonomous substitutions (dN/dS) at the ATPase6 and ATPase8 genes were used to elucidate the potential role of selection in shaping mtDNA geographic distribution. RESULTS: We found high concordance across analyses between the mtDNA regions studied. Both had a high percentage of variable sites (CR = 14.6%; ATP = 9.7%) and both phylogenies clustered eastern wolf haplotypes monophyletically within a North American evolved lineage apart from coyotes. Divergence estimates suggest the putative red wolf sequence is more closely related to coyotes (D(xy)CR = 0.01982 ± 0.00494 SD; D(xy)ATP = 0.00332 ± 0.00097 SD) than the eastern wolf sequences (D(xy)CR = 0.03047 ± 0.00664 SD; D(xy)ATP = 0.00931 ± 0.00205 SD). Neutrality tests on both genes were indicative of the population expansion of coyotes across eastern North America, and dN/dS ratios suggest a possible role for purifying selection in the evolution of North American lineages. dN/dS ratios were higher in European evolved lineages from northern climates compared to North American evolved lineages from temperate regions, but these differences were not statistically significant. CONCLUSIONS: These results demonstrate high concordance between coding and non-coding regions of mtDNA, and provide further evidence that the eastern wolf possessed distinct mtDNA lineages prior to recent coyote introgression. Purifying selection may have influenced North American evolved Canis lineages, but detection of adaptive selection in response to climate is limited by the power of current statistical tests. Increased sampling and development of alternative analytical tools will be necessary to disentangle demographic history from processes of natural selection

    Thermal Starch Properties in Corn Belt and Exotic Corn Inbred Lines and Their Crosses

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    More knowledge is needed about variability of starch functional traits in adapted and exotic germplasm and possible genetic effects of these traits before conducting rigorous inheritance studies and breeding programs for starch quality. We studied and compared the range of variability for starch functional traits in a set of Corn Belt inbred lines with a set of exotic inbred lines from Argentina, Uruguay, and South Africa. Reciprocal hybrids of some of the lines within each set were compared with their parents. Functional traits were examined by using differential scanning calorimetry on starch extracted from single kernels of genotypes. The set of Corn Belt lines had a wider range of values for most traits than did the set of exotic lines. For both sets of lines, the maximum value for peak height index was as high as that previously reported for the waxy endosperm mutant. Although the Corn Belt lines exhibited a wider range of values for range of retrogradation than the exotic lines, the exotic lines showed a wider range of values for percentage retrogradation. Hybrid values were not consistently higher, lower, midpoint, or similar with respect to the values of their parents. This was true regardless of germplasm type or functional trait. Reciprocal cross values showed trends suggesting reciprocal differences, although there was no trend suggesting greater effect of the female parent. These traits seem to be controlled by many modifying effects in addition to major effects. Results indicate that sufficient variability exists in Corn Belt germplasm to conduct breeding and inheritance studies effectively and that there should be potential for breeding for functional traits

    Noradrenaline and cortisol changes in response to low-grade cognitive stress differ in migraine and tension-type headache

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    The goal of this study was to explore the relationship between indicators of sympathoneural, sympathomedullar and hypothalamic-pituitary-adrenocortical (HPA) activity and stress-induced head and shoulder-neck pain in patients with migraine or tension-type headache (TTH). We measured noradrenaline, adrenaline and cortisol levels before and after low-grade cognitive stress in 21 migraineurs, 16 TTH patients and 34 controls. The stressor lasted for 60 min and was followed by 30 min of relaxation. Migraine patients had lower noradrenaline levels in blood platelets compared to controls. Pain responses correlated negatively with noradrenaline levels, and pain recovery correlated negatively with the cortisol change in migraineurs. TTH patients maintained cortisol secretion during the cognitive stress as opposed to the normal circadian decrease seen in controls and migraineurs. There may therefore be abnormal activation of the HPA axis in patients with TTH when coping with mental stress, but no association was found between pain and cortisol. A relationship between HPA activity and stress in TTH patients has to our knowledge not been reported before. In migraine, on the other hand, both sympathoneural activation and HPA activation seem to be linked to stress-induced muscle pain and recovery from pain respectively. The present study suggests that migraineurs and TTH patients cope differently with low-grade cognitive stress

    Dairy Farm Business Summary: Southeastern New York Region 1990

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    A.E. Ext. 91-17Dairy farmers throughout New York State have been participating in Cornell Cooperative Extension's farm business summary and analysis program since the early 1950's. Each participating farmer receives a comprehensive business summary and analysis of his or her farm business. The information in this report represents an average of the data submitted from farms in the Southeastern New York region

    Metabolomic Profiling in LRRK2-Related Parkinson's Disease

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    Mutations in LRRK2 gene represent the most common known genetic cause of Parkinson's disease (PD).We used metabolomic profiling to identify biomarkers that are associated with idiopathic and LRRK2 PD. We compared plasma metabolomic profiles of patients with PD due to the G2019S LRRK2 mutation, to asymptomatic family members of these patients either with or without G2019S LRRK2 mutations, and to patients with idiopathic PD, as well as non-related control subjects. We found that metabolomic profiles of both idiopathic PD and LRRK2 PD subjects were clearly separated from controls. LRRK2 PD patients had metabolomic profiles distinguishable from those with idiopathic PD, and the profiles could predict whether the PD was secondary to LRRK2 mutations or idiopathic. Metabolomic profiles of LRRK2 PD patients were well separated from their family members, but there was a slight overlap between family members with and without LRRK2 mutations. Both LRRK2 and idiopathic PD patients showed significantly reduced uric acid levels. We also found a significant decrease in levels of hypoxanthine and in the ratios of major metabolites of the purine pathway in plasma of PD patients.These findings show that LRRK2 patients with the G2019S mutation have unique metabolomic profiles that distinguish them from patients with idiopathic PD. Furthermore, asymptomatic LRRK2 carriers can be separated from gene negative family members, which raises the possibility that metabolomic profiles could be useful in predicting which LRRK2 carriers will eventually develop PD. The results also suggest that there are aberrations in the purine pathway in PD which may occur upstream from uric acid

    Likely Impact of the COVID-19 Pandemic on Newborn Hearing Screening and Follow-up Services in the United States in 2020

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    This perspective aims to highlight aspects of the Early Hearing Detection and Intervention (EHDI) newborn hearing screening and follow-up processes that were impacted by the COVID-19 pandemic and considers factors that likely impacted follow-up after newborn hearing screening among infants born in the United States during 2020. Efforts to minimize the potential impact of missed or delayed identification of hearing loss in infants and young children will also be discussed to help guide future program improvement activities
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