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Iowa State University

Selected Works

1995

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Articles 1 - 16 of 16

Full-Text Articles in Life Sciences

Variation In Lightness Of White Oak Dimension Stock, Douglas D. Stokke, Anton D. Pugel, John E. Phelps Oct 1995

Variation In Lightness Of White Oak Dimension Stock, Douglas D. Stokke, Anton D. Pugel, John E. Phelps

Douglas D. Stokke

The objectives of this research were to generate a set of sample parameters for the lightness of planed white oak dimension stock, to investigate the effect of grain angle on lightness values, and to determine the level of sampling needed to color match white oak dimension stock on the basis of lightness or darkness as quantified by the parameter L* (psychometric lightness). This information is important when used to determine the feasibility of low-cost portable instruments for evaluating color in an edge-glued hardwood panel production setting. Color measurements were obtained with a portable spectrophotometer interfaced with a notebook computer. The …


Recombinant Soluble Epoxide Hydrolase, Bruce D. Hammock, David F. Grant, Jeffrey K. Beetham Aug 1995

Recombinant Soluble Epoxide Hydrolase, Bruce D. Hammock, David F. Grant, Jeffrey K. Beetham

Jeffrey K. Beetham

The present invention relates to nucleic acid sequences and methods useful for producing recombinant human soluble epoxide hydrolase (sEH).


Light-Dependent And Tissue-Specific Expression Of The H-Protein Of The Glycine Decarboxylase Complex, R. Srinivasan, David J. Oliver Aug 1995

Light-Dependent And Tissue-Specific Expression Of The H-Protein Of The Glycine Decarboxylase Complex, R. Srinivasan, David J. Oliver

David J. Oliver

Glycine decarboxylase is a mitochondrial enzyme complex, which is the site of photorespiratory CO2 and NH3 release. Although the proteins that constitute the complex are located within the mitochondria, because of their intimate association with photosynthesis their expression is controlled by light. Comparisons of the kinetics of mRNA accumulation between the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase and the H-protein of glycine decarboxylase during the greening of etiolated Arabidopsis thaliana suggest that their expression is controlled in parallel. A genomic clone for the H-protein (gdcH) was isolated from Arabidopsis and sequenced. The upstream region from -856 to +62 was fused to …


Clonal-By-Environment Interactions Influence Isoflavonoid Accumulation In Cicer Milkvetch, Andrew W. Lenssen, C. E. Townsend, S. S. Martin May 1995

Clonal-By-Environment Interactions Influence Isoflavonoid Accumulation In Cicer Milkvetch, Andrew W. Lenssen, C. E. Townsend, S. S. Martin

Andrew W. Lenssen

Cicer milkvetch (Astragalus cicer L.) is a perennial, nonbloatinducing forage legume adapted to temperate environments. For unknown reasons, however, ruminants grazing cicer milkvetch in pure stands have become photosensitized, or sunburned, in some environments, Isoflavonoids are involved with diverse biological activities, including estrogenism, disease resistance, and, potentially, photosensitization. We conducted a series of studies from 1991 to 1993 to identify factors that influence the accumulation of isoflavonoids. In separate greenhouse studies, elicited leaflets from the parental clones of ‘Monarch’ and. ‘Windsor’ cicer milkvetch were analyzed for isoflavonoid accumulation. Growth chamber studies were conducted to investigate the clonal variability of leaflet …


Ecological Risk Assessment For Chemical Stressors: Challenges In Predictive Ecotoxicology Research, Steven P. Bradbury Jan 1995

Ecological Risk Assessment For Chemical Stressors: Challenges In Predictive Ecotoxicology Research, Steven P. Bradbury

Steven P. Bradbury

Environmental management decisions are increasingly based on the results of ecological risk assessments that require data and models to establish the likelihood of adverse ecological effects that may occur or are occurring as a result of exposure to one or more stressors .. Research to support ecological risk assessments for chemical stressors must include a predictive capability.. The great number of chemicals, species and habitats (exposure conditions) associated with prospective and retrospective management decisions precludes the use of empirical testing as the sole means to fill data gaps .. Therefore, strategic laboratory and field testing must be undertaken in the …


Sar Models For Futile Metabolism: One-Electron Reduction Of Quinones, Phenols And Nitrobenzenes, Steven P. Bradbury, Ovanes Mekenyan, G. D. Veith, N. Zaharieva Jan 1995

Sar Models For Futile Metabolism: One-Electron Reduction Of Quinones, Phenols And Nitrobenzenes, Steven P. Bradbury, Ovanes Mekenyan, G. D. Veith, N. Zaharieva

Steven P. Bradbury

Benzoquinones, naphthoquinones and aziridinylbenzoquinones, can be reduced by flavoproteins to semiquinones that react with molecular oxygen to form superoxide anion with the subsequent regeneration of the parent compounds. This redox cycling, a form of futile metabolism, produces reactive oxygen species and depletes the reducing equivalents of cells without concomitant energy production. The ability of a toxicant to redox cycle is related to its one-electron reduction potential, and this study attempted to estimate reduction potential from structure using semi-empirical quantum chemical models for a diverse set of chemicals. The results of this study suggest that one-electron reduction potentials, within structural classes …


Chivalry In Pholcid Spiders Revisited, Julie A. Blanchong, Michael S. Summerfield, Mary A. Popson, Elizabeth M. Jakob Jan 1995

Chivalry In Pholcid Spiders Revisited, Julie A. Blanchong, Michael S. Summerfield, Mary A. Popson, Elizabeth M. Jakob

Julie A. Blanchong

Cohabiting pairs of adult spiders are likely to interact over prey, and the outcome of these interactions is likely to affect the reproductive success of both individuals. In two species of pholcid spiders, previous workers reported the occurrence of "chivalrous" behavior, in which males cede prey to females. We looked for the occurrence of chivalrous behavior in another pholcid spider, Holocnemus pluchei. Pairs of spiders were placed on a web and left overnight without prey. A housefly was then introduced onto the web equidistant from the spiders, and subsequent interactions were noted on audiotape. We found no evidence of chivalry …


Quantitative Structure-Activity Relationships And Ecological Risk Assessment: An Overview Of Predictive Aquatic Toxicology Research, Steven P. Bradbury Jan 1995

Quantitative Structure-Activity Relationships And Ecological Risk Assessment: An Overview Of Predictive Aquatic Toxicology Research, Steven P. Bradbury

Steven P. Bradbury

In the field of aquatic toxicology, quantitative structure-activity relationships (QSARs) have developed as scientifically credible tools for predicting the toxicity of chemicals when little or no empirical data are available. A fundamental understanding of toxicological principles has been considered an important component to the acceptance and application of QSAR approaches as biologically relevant in ecological risk assessments. As a consequence, there has been an evolution of QSAR development and application from that of a chemical-class perspective to one that is more consistent with assumptions regarding modes of toxic action. In this review, techniques to assess modes of toxic action from …


Use Of Knowledge Bases And Qsars To Estimate The Relative Ecological Risk Of Agrichemicals: A Problem Formulation Exercise, Steven P. Bradbury, C. L. Russom, A. R. Carlson Jan 1995

Use Of Knowledge Bases And Qsars To Estimate The Relative Ecological Risk Of Agrichemicals: A Problem Formulation Exercise, Steven P. Bradbury, C. L. Russom, A. R. Carlson

Steven P. Bradbury

Ecological risk assessments can be used to establish the likelihood that an adverse effect will result from exposure to one or more chemicals. When evaluating contaminated sites with many chemicals present, risk assessors must grapple with the problem of quickly identifying the chemicals that are most likely to be of concern, based on effect and exposure assessment information. Many times data gaps exist and the risk assessor is left with decisions on which models to use to estimate the parameter of concern. In the present paper, a procedure is presented for ranking agrichemicals, utilizing the ASTER (ASsessment Tools for the …


Gene Evolution Of Epoxide Hydrolases And Recommended Nomenclature, Jeffrey K. Beetham, David Grant, Michael Arand, Joan Garbarino, Tomohiro Kiyosue, Franck Pinot, Franz Oesch, William R. Belknap, Kazuo Shinosaki, Bruce D. Hammock Jan 1995

Gene Evolution Of Epoxide Hydrolases And Recommended Nomenclature, Jeffrey K. Beetham, David Grant, Michael Arand, Joan Garbarino, Tomohiro Kiyosue, Franck Pinot, Franz Oesch, William R. Belknap, Kazuo Shinosaki, Bruce D. Hammock

Jeffrey K. Beetham

We have analyzed amino acid sequence relationships among soluble and microsomal epoxide hydrolases, haloacid dehalogenases, and a haloalkane dehalogenase. The amino-terminal residues (1-229) of mammalian soluble epoxide hydrolase are homologous to a haloacid dehalogenase. The carboxy-terminal residues (230-554) of mammalian soluble epoxide hydrolase are homologous to haloalkane dehalogenase, to plant soluble epoxide hydrolase, and to microsomal epoxide hydrolase. The shared identity between the haloacid and haloalkane dehalogenases does not indicate relatedness between these two types of dehalogenases. The amino-terminal and carboxy-terminal homologies of mammalian soluble epoxide hydrolase to. the respective dehalogenases suggests that this epoxide hydrolase, but not the soluble …


A Muscle Hypertrophy Condition In Lamb (Callipyge): Characterization Of Effects On Muscle Growth And Meat Quality Traits, M. Koohmaraie, S. D. Shackelford, T. L. Wheeler, Steven M. Lonergan, M. E. Doumit Jan 1995

A Muscle Hypertrophy Condition In Lamb (Callipyge): Characterization Of Effects On Muscle Growth And Meat Quality Traits, M. Koohmaraie, S. D. Shackelford, T. L. Wheeler, Steven M. Lonergan, M. E. Doumit

Steven M. Lonergan

The present experiment was conducted to determine the effect of the callipyge phenotype on traits affecting muscle growth and meat tenderness. Dorset wethers (n = 40) that were either carriers or non-carriers were fed grain and slaughtered at 169 d of age. Callipyge phenotype did not affect ( P > .05) slaughter weight, hot carcass weight, or weights of the heart, spleen, viscera, kidney-pelvic fat, head, and pelt; however, callipyge lambs had a higher dressing percentage and lighter lungs, liver, and kidneys ( P < .01). Callipyge lambs had reduced fat thickness and marbling score and higher leg scores and longissimus area (34%). Adductor (30%), biceps femoris (42%), gluteus group (31%), longissimus (32%), psoas group (20%), quadriceps femoris (18%), semimembranosus (38%), and semitendinosus (26%) weights were higher in the callipyge phenotype ( P < .01); however, phenotype did not affect ( P > .05) weights of infraspinatus or supraspinatus. Longissimus pH and temperature declines were not affected ( P > .05) …


Delayed-Incubation Method For Microbiological Analysis Of Environmental Specimens And Samples, James S. Dickson, M. H. Brodsky, C. A. Davidson, M. J. Pettis, T. L. Tieso Jan 1995

Delayed-Incubation Method For Microbiological Analysis Of Environmental Specimens And Samples, James S. Dickson, M. H. Brodsky, C. A. Davidson, M. J. Pettis, T. L. Tieso

James S. Dickson

Five laboratories compared the quantitative recovery of heterotrophic bacteria, yeasts and molds, coliforms, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus from a variety of naturally contaminated food and water samples, using traditional incubation procedures and a delayed-incubation method. Refrigeration of inoculated media for up to 3 days prior to incubation was shown to be a viable option for many quantitative analyses, but needs to be validated for each application. Some inoculated media withstood refrigeration for up to 7 days prior to incubation without any detrimental effect on the recovery of target cells, while the incubation of other media for similar …


Relationship Of Restriction Fragment Length Polymorphisms (Rflp) At The Bovine Calpastatin Locus To Calpastatin Activity And Meat Tenderness, Steven M. Lonergan, C. W. Ernst, M. D. Bishop, C. R. Calkins, M. Koohmaraie Jan 1995

Relationship Of Restriction Fragment Length Polymorphisms (Rflp) At The Bovine Calpastatin Locus To Calpastatin Activity And Meat Tenderness, Steven M. Lonergan, C. W. Ernst, M. D. Bishop, C. R. Calkins, M. Koohmaraie

Steven M. Lonergan

Restriction fragment length polymorphisms (RFLP) have been identified at the bovine calpastatin locus. The objective of the present study was to determine whether these polymorphisms are related to variations in calpastatin activity or beef tenderness in unrelated animals of mixed breeding. A sample of 83 crossbred steers from sires representing eight different breeds was examined to determine this relationship. A 2.2-kb cDNA coding for domains 2 through 4 plus a 3¢ untranslated region of bovine skeletal muscle calpastatin was used as a probe for calpastatin RFLP. Polymorphisms were found using the restriction enzymes BamHI and EcoRI. Polymorphic restriction fragments for …


Crop Yield Mapping: Comparison Of Yield Monitors And Mapping Techniques, Stuart J. Birrell, Steven C. Borgelt, Kenneth A. Sudduth Jan 1995

Crop Yield Mapping: Comparison Of Yield Monitors And Mapping Techniques, Stuart J. Birrell, Steven C. Borgelt, Kenneth A. Sudduth

Stuart J. Birrell

Although the variability in soil nutrients and crop yields has been well documented since the turn of the century (Robinson & Lloyd, 1915; Fairfield Smith, 1938), the mechanization of agriculture and the trend to larger implements has led to larger areas being treated as a single unit. Recent advances, however, in machine technology and improvements in data management have made it possible to reverse this trend by implementing site specific crop management (Goering, 1993).


Comparison Of Variable Rate To Single Rate Nitrogen Fertilizer Application: Corn Production And Residual Soil No3-N, N. R. Kitchen, D. F. Hughes, K. A. Sudduth, Stuart J. Birrell Jan 1995

Comparison Of Variable Rate To Single Rate Nitrogen Fertilizer Application: Corn Production And Residual Soil No3-N, N. R. Kitchen, D. F. Hughes, K. A. Sudduth, Stuart J. Birrell

Stuart J. Birrell

The questions most often asked by farmers when discussing variable rate (VR) fertilizer inputs are "How much will it cost?" and "How will it affect my yields?" Many farmers and custom application services share a reluctance to invest in the time and technology required for variable fertilizer application since studies to answer these questions are few and results have been inconsistent.


Technical Notes: Bidirectional Serial-To-Parallel Converter For Data Acquisition And Control, Stuart J. Birrell, Scott T. Drummond, Kenneth A. Sudduth Jan 1995

Technical Notes: Bidirectional Serial-To-Parallel Converter For Data Acquisition And Control, Stuart J. Birrell, Scott T. Drummond, Kenneth A. Sudduth

Stuart J. Birrell

A bidirectional serial-to-parallel converter was created to allow collection of serial data through the parallel port on a portable laptop computer. The converter consisted of both hardware conversion circuitry and control software. The converter supported both input and output at a variety of transmission formats and adjustable transmission rates. The control software made use of the various I/O registers of the parallel port to collect data and control the hardware circuitry.