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Papers by Stephen Mason

With the highly variable precipitation in the Great Plains, improving the probabilities of having... more With the highly variable precipitation in the Great Plains, improving the probabilities of having soil water available during the critical silking to blister stage of corn development will improve the chances of success of rainfed corn production. The idea behind skip-row planting is to ...

Proteomics. Clinical applications, Jan 24, 2009

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is characterized by the development of numer... more Autosomal Dominant Polycystic Kidney Disease (ADPKD) is characterized by the development of numerous fluid-filled cysts in the kidneys of patients. We recently published our description of the proteome of renal cyst fluid in ADPKD. As a follow-up experiment, we hypothesized that the protein-bound subfraction consists of molecules of mechanistic or diagnostic interest in ADPKD. Using a manual biomarker enrichment kit, we have identified 44 distinct proteins in human cyst fluid.

Nephron Experimental Nephrology, 2011

Background: Meckel syndrome (MKS) is a fatal autosomal recessive condition with prominent renal c... more Background: Meckel syndrome (MKS) is a fatal autosomal recessive condition with prominent renal cystic pathology. Renal protein misexpression was evaluated in the Wpk rat model of human MKS3 gene disease to identify biomarkers for the staging of renal cystic progression. Methods: Misexpressed proteins were compared between early and late stages of MKS renal cystic disease using proteomic analysis (two-dimensional gel electrophoresis with LC-MS/MS identification) followed by Western blot analysis. Results: A proteomic analysis identified 76 proteins with statistically different, normalized abundance in at least one group. Subsequently, Western blot was used to confirm differential expression in several of these and polycystic kidney disease (PKD)-associated proteins. Galectin-1 and vimentin were identified as overexpressed proteins, which have been previously found in the jck mouse model of nephronophthisis 9. Ciliopathic PKD proteins, polycystins 1 & 2, and fibrocystin were also dif...

Experimental Gerontology, 2008

The aging heart undergoes well characterized structural changes associated with functional declin... more The aging heart undergoes well characterized structural changes associated with functional decline, though the underlying mechanisms are not understood. The aim of this study was to determine to what extent ventricular myocardial protein expression was altered with age and which proteins underwent protein nitration. Fischer 344 X Brown Norway F1 hybrid (FBN) rats of four age groups were used, 4, 12, 24, and 34 months. Differential protein expression was determined by 2-DE and proteins were identified by peptide mass fingerprinting. Altered protein nitration with age was assessed by immunoblotting. Over 1,000 protein spots per sample were detected, and 255 were found to be differentially expressed when all aged groups were compared to young rats (4 months) (p ≤ 0.05). A strong positive correlation between differential protein expression and increasing age (p=0.03, R 2 =0.997) indicated a progressive, rather than abrupt, change with age. Of 46 differentially expressed proteins identified, 17 have roles in apoptosis, 10 in hypertrophy, 7 in fibrosis, and 3 in diastolic dysfunction, aging-associated processes previously reported in both human and FBN rat heart. Protein expression alterations detected here could have beneficial effects on cardiac function; thus, our data indicate a largely adaptive change in protein expression during aging. In contrast, differential protein nitration increased abruptly, rather than progressively, at 24 months of age. Altogether, the results suggest that differential myocardial protein expression occurs in a progressive manner during aging, and that a proteomic-based approach is an effective method for the identification of potential therapeutic targets to mitigate aging-related myocardial dysfunction.

Journal of Agronomic Education, 1987

South African Journal of Plant and Soil, 2009

ABSTRACT Grain sorghum [Sorghum bicolor (L.) Moench] is the major cereal crop used in the Central... more ABSTRACT Grain sorghum [Sorghum bicolor (L.) Moench] is the major cereal crop used in the Central Plateau of Burkina Faso to produce the traditional beer called “dolo”. Experiments combining five water management techniques (WMT) and four fertilizer treatments (FT) in a randomized complete block design with a split-plot arrangement of treatments were conducted from 2003 to 2005. Water management techniques were allocated to main plots and FT to subplots. The objective was to determine the best cropping practice to optimize yields for two red grain sorghum varieties, IRAT9 and ICSV1001 (Framida), commonly used for dolo production. Results indicated that water conservation using tied-ridges produced higher grain yields. The highest yield benefit was 241 kg ha−1 for Framida. In the IRAT9 field, the highest yield benefit of 395 kg ha−1occurred in the lowest rainfall year (736 mm) of 2005. In all years, microdose consisting of application of 19 kg N ha−1, 19 kg P ha−1 and 19 kg K ha−1 as complex fertilizer NPK at planting, with addition of 20 kg P ha−1 as triple super phosphate at planting in the planting hole and 30 kg N ha−1 as urea applied 45 days after planting (microdose + 20 kg P ha−1 + 30 kg N ha−1) produced the highest grain yield increases from 420 to 756 kg ha−1 for Framida and from 812 to 1346 kg ha−1 for IRAT9. In the IRAT9 field, microdose + 20 kg P ha−1 + 30 kg N ha−1 produced the highest grain yield in all WM treatments, with yield increases from 518 to 1327 kg ha−1 depending on the WMT. Correlations indicated that the number of panicles harvested ha−1 were associated with grain yield for the two varieties. The best cropping system to optimize grain yield of Framida and IRAT9 was the use of tied-ridges and application of micro-dose + 20 kg P ha−1 + 30 kg N ha−1.

Journal of Plant Nutrition, 1993

The proportion of straw and grain as well as of nitrogen (N) in the barley (Hordeum vulgare L.) p... more The proportion of straw and grain as well as of nitrogen (N) in the barley (Hordeum vulgare L.) plant was greatly changed by the distribution of rain in the pre‐ and post‐anthesis periods and by the existence of air temperatures above 30°C during grain filling along with N fertilizer rate. The response of barley to N rates of 0, 40,

Communications in Soil Science and Plant Analysis, 2001

ABSTRACT Spatial variability in crop yields can be caused by many factors, which makes it difficu... more ABSTRACT Spatial variability in crop yields can be caused by many factors, which makes it difficult to determine the most limiting factors. Application of animal wastes to relatively infertile areas offers the potential to supply needed nutrients and improve soil physical properties. The objectives of this study were to test a manure application strategy to reduce spatial variability in corn (Zea mays L) yield and to identify the most limiting nutrients in relatively low yielding areas in a field. Fresh solid beef feedlot manure was applied in 1997 to a strip across areas with variable fertility status. No fertilizer was applied with the manure in 1997. Uniform N fertilizer, but no manure, was applied in 1998. Leaf tissue samples and chlorophyll meter readings were collected along the strips during the growing season and from adjacent strips without manure application. Grain yield was determined at plant maturity. In 1997, chlorophyll meter readings indicated season long N deficiency (<95% sufficiency index) in no-manure plots with sufficiency indices of 93, 88, 85, and 88% for the V10, V17, R2, and R3 growth stages, respectively. Only an early season N deficiency was detected in a few of the no-manure plots in 1998. Leaf tissue analyses indicated N and P were growth limiting factors in 1997, with leaf N concentrations of 25, 26, and 27 mg g−1 for non-manure plots and 30, 33, and 31 mg g−1 for manure plots at V12, R1, and R3 growth stages, respectively. Leaf P concentrations were 2.0, 2.0, and 1.9 mg g−1 for no-manure plots versus 2.5, 2.7, and 2.3 mg g−1 for manure plots, respectively. In 1998, neither N or P were identified as limiting factors. Grain yields in 1997 were 10.2 and 12.2 Mg ha−1, which increased to 11.9 and 12.8 Mg ha−1 in 1998 for no-manure and manure plots, respectively.

jpa, 1992

Corn (Zea mays L.) producers are interested in quantifying interactions of hybrid, fertility and ... more Corn (Zea mays L.) producers are interested in quantifying interactions of hybrid, fertility and water regime production practices as they relate to grain yield and quality. This study was conducted to determine the interaction effects of corn hybrid with soil N level and water regime (WR) on grain yield, protein content (GP), kernel breakage susceptibility (KBS), kernel density (KD), and N use efficiency (NUE). In 1987 and 1988, a splitsplit plot designed experiment with six commercial corn hybrids, six soil N levels, and two water regimes (irrigated and nonirrigated) was conducted at Mead, NE, on a Sharpsburg silty clay loam soil (fine montmorillinitic, mesic Typic Arguidoll). In the low rainfall year of 1988, grain yields increased linearly for hybrids 442,688,488, and 692 as soil N levels increased, while hybrids 629 and 212 grain yields increased quadratically and peaked at 185 to 235 Ib/acre soil N levels. Increasing soil N level decreased KBS of all hybrids, but hybrid response was inconsistent across WR and years. In 1988, irrigation resulted in denser kernels by 0.0400 to 0.0475 g/ml, except for hybrid 442, whose KD was only 0.0273 g/ml greater. In 1987, GP of hybrids 442, 629, 692, 212, and 488 increased linearly as soil N levels increased while the GP of hybrid 688 peaked at the 235 Ib/acre soil N level. In 1988, GP of hybrid 688 was similar across WR while all other hybrids had 1.9 to 2.5% higher GP on nonirrigated plots. In 1987 and on irrigated plots in 1988, NUE differences were greater at soil N levels below 85 Ib/acre with hybrid 442 having the highest NUE. Producers considering use of low fertilizer N rates must recognize importance of corn hybrid selection for high grain yield and NUE, and that low N levels reduce grain quality as measured by KBS, KD, and GP. C ORN PRODUCERS are interested in the interactive nature of production practices, especially as it relates to grain yield and quality. In the western Corn

NACTA journal

Enrollment declines in colleges of agriculture and particularly in agronomy majors threaten the v... more Enrollment declines in colleges of agriculture and particularly in agronomy majors threaten the viability of these programs. One consequence is a reduction in the availability of educated professionals for the agricultural industry. This paper surveysthe numbers of students receiving ...

Crop Science, 2016

RESEARCH M aize grain yield response to increasing plant population is inconsistent across enviro... more RESEARCH M aize grain yield response to increasing plant population is inconsistent across environments, soil types, and hybrids. Maize yield response to plant population in high-yield environments often follows quadratic (

Nacta Journal, Dec 1, 2005

Pearl millet [Penisetum glaucum (L.) R.Br.] and cowpea [Vigna unguiculata (L.) Walp] are importan... more Pearl millet [Penisetum glaucum (L.) R.Br.] and cowpea [Vigna unguiculata (L.) Walp] are important crops in traditional bush-fallow production systems in West Africa. Human population growth is forcing producers to consider alternative cropping systems and fertilizer application to meet food needs, by continuous, intercrop and rotational cropping systems on pearl millet and cowpea grain and stover yield, and maintaining soft nutrient levels. A long-term cropping system study with nitrogen applications of zero 20 and 40 kg ha-1 was initiated at the Cinzana Research Station near Segou, Mali in 1990. The field had a leached tropical ferruginous (Ustalf) soil. Nitrogen fertilizer application increased pearl millet and stover yield linearly per year, but had no effect on cowpea. Rotation with cowpea increased pearl millet grain yield by 17 to 31% each year between 1991 and 1995, but had little effect on cowpea yield. Intercropping reduced yield of both crops every year, but the Land Equi...

Soil Science Society of America Journal, 1989

(…) The experiment was conducted on a Sharpsburg silty clay loam (fine, montmorillinitic, mesic, ... more (…) The experiment was conducted on a Sharpsburg silty clay loam (fine, montmorillinitic, mesic, Typic Argiudoll) near Mead, NE. Fertilizer treatments consisted of: 1) control (no fertilizer); 2) N at 45 kg ha −1 on soybean plots and 90 kg ha −1 on grain sorghum plots; and 3) manure applied at 15.8 Mg dry weight ha −1 yr −1 . Roots were sampled to a depth of 120 cm in 1986 and 150 cm in 1987. Root densities were reduced at most depths when soybean had been grown the previous year. (…)

International Reviews in Physical Chemistry, 1983

Abstract The development of the conception of handedness in the physical world is outlined, culmi... more Abstract The development of the conception of handedness in the physical world is outlined, culminating with the views of Pasteur on the role of chiral structures and dissymmetric forces in nature. The evolution is traced of the general conclusion that steric congruence dominates chiral discrimination in biochemical enantioselection, asymmetric organic synthesis, the crystal structures of enantiomers and racemates, and the distinction between homochiral and heterochiral interactions in the fluid state. The significance of the unification of the electromagnetic with the weak interaction is discussed with reference to the proposed universality of optical activity, and of the particular terrestrial enantioselection observed in natural products.

Crop Science, 1989

Grain quality is important to farmers, grain elevators, millers, and domestic and foreign buyers.... more Grain quality is important to farmers, grain elevators, millers, and domestic and foreign buyers. Excessive broken kernels can reduce the grade of grain, lower the selling price farmers receive, decrease production from dry and wet milling processes, reduce artificial drying efficiency, and increase potential dust hazards. However, little attention has been focused on the influence of production practices on grain quality. This study was conducted to determine whether irrigation and soil N levels would affect the quality of maize (Zea mays L.) grain. Two water regimes and five N fertilization levels ranging from zero to 360 kg ha-i were applied to two normal and two opaque-2 hybrids. The experimental site was a Sharpsburg silty clay loam (fine, montmorillinitic, mesic, Typic Argiudoll) near Mead, NE. Opaque-2 grain was 2.4 times more susceptible to breakage, and 8% lower in density than normal grain. Irrigation increased kernel breakage susceptibility (KBS) from 13.5 to 17.9, 3.2 to 3.8, and 5.4 to 7.3% in 1985, 1986, and 1987, respectively. Increasing soil N levels decreased KBS for all hybrids. Kernel density (KD) of opaque-2 grain was increased with irrigation but decreased with higher N levels. In contrast, KD of normal grain decreased with irrigation but increased with higher N levels. Average grain yields were 9.4, 7.3, and 5.5 Mg ha-1, with irrigation increasing yields 28, 9, and 27% over nonirrigation in 1985, 1986, and 1987, respectively. Normal hybrids averaged 5% greater yields than opaque-2 hybrids. Yield increased quadratically with N rate within each moisture regime in each year. Results indicate production practices influence KBS and KD as well as yield, and may become important considerations in the future.

Crop Science, 1991

Increasing soil N fertility has been found to have detrimental effects on the nutritional quality... more Increasing soil N fertility has been found to have detrimental effects on the nutritional quality of maize (Zea mays L.) grain; however, little research has evaluated the effects of irrigation on these factors. Most previous work has been done with inbred lines rather than high-yielding commercial hybrids. This study was conducted to determine how irrigation and soil N levels would affect the content of protein and lysine plus the quality of maize protein as measured by the lysine in protein (LP). Two water regimes and five soil N levels were applied to two normal and two opaque-2 commercial hybrids grown on a Sharpsburg silty clay loam soil (fine, montmorillinitic, mesic Typic Argiudoll). The hybrid X year interaction indicated that in 1985 and 1987 the short-season opaque-2 hybrid (SO) had a greater yield than the short-season normal hybrid (SN) by «8%, whereas the long-season normal hybrid (LN) had a greater yield than the long-season opaque-2 hybrid (LO) by 4 to 12%. In 1986, normal and opaque-2 hybrids produced similar yields. Irrigation increased yield, decreased protein content (PT) 5 to 7 g kg-1 , and increased LP by 1 to 2 g kg-1 in 1985 and 1986. Irrigation also decreased lysine in sample (LS) 0.3 g kg* 1 for opaque-2 grain. Conversely, increasing soil N levels increased yield, PT, and LS, while LP decreased quadratically from 0.39 to 0.36 % kg-1. Grain yield was maximized by production of LN hybrids with irrigation and high soil N levels. The highest PT levels were produced with normal hybrids with high soil N levels without irrigation. Grain produced by opaque-2 hybrids under low soil N conditions without irrigation had the best protein quality as indicated by LP. Results from the study indicate that both grain yield and nutritional quality are influenced by hybrid selection, irrigation, and N fertilization, which should be considered by producers of nonruminant livestock.

Communications in Soil Science and Plant Analysis, 2006

Abstract Pearl millet is a potential dryland crop for Nebraska. Experiments were conducted in eas... more Abstract Pearl millet is a potential dryland crop for Nebraska. Experiments were conducted in eastern Nebraska in 2000, 2001, and 2002, and in western Nebraska in 2000 and 2001. The objectives were to determine optimum nitrogen (N) rate, N uptake, and N use ...

Agronomy Journal, 1999

nutrient-poor soil and low rainfall conditions, yet it is capable of rapid and vigorous growth un... more nutrient-poor soil and low rainfall conditions, yet it is capable of rapid and vigorous growth under favorable Pearl millet [Pennisetum glaucum (L.) R. Br.] is a staple grain conditions (Maiti and Bidinger, 1981). Pearl millet is a crop in the arid and semiarid regions of Africa and India, and a new potential alternative grain crop for areas of the Great grain crop in the USA. A 2-year field experiment was conducted near Mead, NE, in 1995 and 1996 on a Sharpsburg silty clay loam (fine, Plains with sandy soil, low rainfall, and a short growing smectitic, mesic Typic Argiudoll) soil with approximately 29 g kg Ϫ1 season since dwarf hybrids with good yield potential organic matter, 35 kg ha Ϫ1 NO 3-N, and pH of 6.0. The objective was have been developed. A better understanding of pearl to determine the influence of hybrid and N on grain yield, dry matter millet growth and its N concentration and accumulation accumulation and partitioning, and growth rates throughout the growis necessary to improve pearl millet grain yield and ing season. Nitrogen concentrations, uptake, and use efficiency were promote its adoption by farmers in the Great Plains. also determined. Treatments were a factorial combination of the pearl Growth rate is a physiological trait associated with millet dwarf hybrids (59022A ϫ 89-0083, 1011A ϫ 086R, and 1361M ϫ increased grain yield in cereal crops. Growth is generally 6Rm) and N levels (0 and 78 kg ha Ϫ1) in a randomized complete a function of environmental factors (such as temperablock design. Two plants per plot were sampled at 2-wk intervals ture and solar radiation) and mineral nutrition, along and partitioned into plant parts, dried, weighed, and analyzed for N concentration. Applied N increased grain yield by 0.4 to 0.5 Mg ha Ϫ1 , with genotype and production practices. General asbut had only a small effect on dry matter accumulation and partipects of growth and development of pearl millet plants tioning. Hybrid differences were small for grain yield. Pearl millet dry were reported by Maiti and Bidinger (1981) and Bramelmatter accumulation increased cubically in both years, with maximum Cox et al. (1984). Dry matter accumulation by pearl crop growth rates among hybrids ranging from 0.48 to 0.57 g m Ϫ2 per millet under different management conditions have growing degree day (GDD) in 1995 and ranging from 1.9 to 3.1 g m Ϫ2 been reported in Africa (Azam-Ali et al., 1984), Austra-GDD Ϫ1 maximum in 1996. The relative growth rate among hybrids lia (Coaldrake and Pearson, 1985), and India (Craufurd declined from 0.012 to 0.020 g Ϫ1 m Ϫ2 GDD Ϫ1 in both years to near and Bidinger, 1989; Carberry et al., 1985). zero at physiological maturity. Nitrogen concentrations were higher Mineral nutrition is one of the most important factors during the vegetative stages and decreased with plant age. Applied affecting plant productivity (Clark, 1990), and N is the N decreased N use efficiency for aboveground biomass (NUE 1) by 18 to 25 g DM g Ϫ1 N, and N use efficiency for grain (NUE 2) by 7 to major nutrient required by pearl millet. Pearl millet is 12 g grain g Ϫ1 N. Environmental variability due to years had a greater usually managed with low fertilizer input, and has shown effect on yield, growth, and N levels than hybrid and applied N. variable growth and yield response to N application (Gascho et al., 1995). Coaldrake and Pearson (1985) reported that growth of pearl millet was reduced by low P earl millet is commonly grown in the arid and N supply, and maximum growth rate before panicle semiarid regions of Africa and India as a staple initiation was achieved at a whole-plant N concentration food for millions of people. It is particularly adapted to of 15.6 g kg Ϫ1 during vegetative growth and 13 g kg Ϫ1 after panicle initiation. Alagarswamy and Bidinger (1987) found that increased N application decreased N Dep. of Agronomy, Univ. of Nebraska, Lincoln, NE 68583-0915. Paper use efficiency. Gregory (1979) found that N concentrano. 12259 of the Journal Series of the Nebraska Agric. Res. Div. tion in pearl millet stems and leaves increased with water Contribution of the Univ. of Nebraska-Lincoln Dep. of Agronomy.