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Articles 1261 - 1290 of 1513

Full-Text Articles in Life Sciences

Genetic Variation Among Populations Of River Otters In North America: Considerations For Reintroducing Projects, Thomas L. Serfass, Robert P. Brooks, James M. Novak, Paul E. Johns, Olin E. Rhodes Jr. Jan 1998

Genetic Variation Among Populations Of River Otters In North America: Considerations For Reintroducing Projects, Thomas L. Serfass, Robert P. Brooks, James M. Novak, Paul E. Johns, Olin E. Rhodes Jr.

James M. Novak

Horizontal starch gel electrophoresis was used to assess variability at 23 presumptive gene loci of 732 river otters obtained from fur-trappers in 18 states and three Canadian provinces. States and provinces providing otters were sorted into eight geographic regions for genetic comparisons. Multilocus heterozygosity and polymorphism ranged from 0.018 to 0.032 and 0.044 to 0.087, respectively. One locus, esterase-2, (EST-2) demonstrated a high level of polymorphism throughout all regions. Malate dehydrogenase-1 (MDH-1) was polymorphic throughout the Mississippi drainage but not elsewhere. Heterozygosity, occurrence of rare alleles, and mean number of alleles per locus were associated positively ...


Evaluation Of Molar Size As A Basis For Distinguishing Wild Boar From Domestic Swine: Employing The Present To Decipher The Past, John J. Mayer, James M. Novak, I. Lehr Brisbin Jr. Jan 1998

Evaluation Of Molar Size As A Basis For Distinguishing Wild Boar From Domestic Swine: Employing The Present To Decipher The Past, John J. Mayer, James M. Novak, I. Lehr Brisbin Jr.

James M. Novak

No abstract provided.


Species Delineation And The Identification Of Evolutionarily Significant Units: Lessons From The Freshwater Mussel Genus Potamilus (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard Jan 1998

Species Delineation And The Identification Of Evolutionarily Significant Units: Lessons From The Freshwater Mussel Genus Potamilus (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard

Kevin J. Roe

Accurate identification of biological entities is critical to the timely and efficient preservation of biodiversity. Concepts that define segments of biological diversity--species and evolutionarily significant units (ESUs)--should reflect our current knowledge of the biological world. Conflation of different hierarchical definitions of taxa has the potential to obscure distinct biological entities in need of protection. The concept of the ESU has been criticized because it includes within its definition distinct biological entities that otherwise would be recognized as species. Herein we evaluate several versions of the evolutionary significant unit concept and provide as a case study an analysis of geographic ...


The Role Of Ligand Flexibility In Predicting Biological Activity: Structure–Activity Relationships For Aryl Hydrocarbon, Estrogen, And Androgen Receptor Binding Affinity, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley Jan 1998

The Role Of Ligand Flexibility In Predicting Biological Activity: Structure–Activity Relationships For Aryl Hydrocarbon, Estrogen, And Androgen Receptor Binding Affinity, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley

Steven P. Bradbury

Recent studies indicate that the potency and agonist or antagonist activity of steroid hormone ligands are dependent, in part, on ligand–receptor binding affinity as well as the conformation of the ligand–receptor complex. The binding of ligands to hormone receptors is thought to involve interactions by which shapes of both the receptor and ligand are modified in the formation of the ligand–receptor complex. As a consequence, it is essential to explore the significance of ligand flexibility in the development of screening-level structure–activity relationships. In this review, examples are provided of techniques used to generate and screen ligand ...


Leaf Fluctuating Assymetry Increases With Hybridization And Elevation In Tree-Line Birches, Brian J. Wilsey, Erkki Haukioja, Julia Koricheva, Matti Sulkinoja Jan 1998

Leaf Fluctuating Assymetry Increases With Hybridization And Elevation In Tree-Line Birches, Brian J. Wilsey, Erkki Haukioja, Julia Koricheva, Matti Sulkinoja

Brian J. Wilsey

Fluctuating asymmetry (FA), or random non-directional deviations from perfect symmetry in bilaterally or radially symmetrical traits, has recently been proposed to be a useful indicator of genetic and environmental stress. However, the factors underlying fluctuating asymmetry, especially in plants, remain poorly understood. We sampled leaf fluctuating asymmetry among and within three species of even-aged birch (Betula pubescens, B. nana, and B. pendula) and their interspecific hybrids growing in common gardens of northern Finland to determine whether hybridization and environmental stress are associated with increased developmental instability. Our predictions were that: (1) interspecific hybrids among B. pubescens, B. nana, and B ...


Molecular Systematics Of The Freshwater Mussel Genus Potamilu (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard Jan 1998

Molecular Systematics Of The Freshwater Mussel Genus Potamilu (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard

Kevin J. Roe

Few explicit hypotheses for the relationships of unionid mussels exist. The absence of explicit phylogenetic hypotheses is problematic and is in part responsible for the lack of taxonomic stability seen in this group. In this paper we examine the relationships of mussels in the genus Potamilus, based upon the DNA sequences of a 600 base pair portion of the first subunit of the mitochondrial cytochrome c oxidase (COI) gene. We also examine the genetic distinctiveness of populations of the inflated heelsplitter P. inflatus. The molecular phylogeny indicates that Potamilus is paraphyletic with Leptodea fragilis and Lampsilis ornata nested between P ...


A Comparison Of Iron Absorption In Adults And Infants Consuming Identical Infant Formulas, Richard F. Hurrell, Lena Davidsson, Manju B. Reddy, Peter Kastenmayer, James D. Cook Jan 1998

A Comparison Of Iron Absorption In Adults And Infants Consuming Identical Infant Formulas, Richard F. Hurrell, Lena Davidsson, Manju B. Reddy, Peter Kastenmayer, James D. Cook

Manju B. Reddy

Fe absorption was estimated in adults and infants from the erythrocyte incorporation of Fe isotopes added to infant formula. Fe absorption was measured in adults using radioisotopes, and in infants with a stable-isotope technique. In adults, the geometric mean Fe absorption from a ready-to-feed soya formula with its native phytic acid content was 2.4%. This increased to 6.0 % (P < 0.05) after almost complete dephytinization. In infants, mean Fe absorption values were 3.9 and 8.7% respectively from the same products (P(O.05). In adults, mean Fe absorption from a spray-dried soya formula containing 110 mg ascorbic acid was 4.1 %, increasing to 5.3 % (P < 0.05) when ascorbic acid was doubled to 220 mgfl. In infants, mean Fe absorption values were 5.7 and 9.5 % (P < 0.05) from the same products. Mean Fe absorption from a milk-based formula was 6.5 % in adults compared with 6.7 % in infants. All meals in the adult and infant studies were fed using an identical meal size of 217 g. Increasing the meal size threefold in adults did not change fractional Fe absorption. Mean Fe absorption values for each meal were lower in adults than in infants, but the relative inhibitory effect of phytic acid and the enhancing effect of ascorbic acid were similar. We conclude that Fe absorption studies in adults can be used to assess the influence of enhancers and inhibitors of Fe absorption in infant formulas fed to infants. Further studies, however, are required to extend these findings to weaning foods and complete meals.


Evolutionary Genetics And Genetic Variation Of Haplodiploids And X-Linked Genes, Philip W. Hedrick, Joel D. Parker Nov 1997

Evolutionary Genetics And Genetic Variation Of Haplodiploids And X-Linked Genes, Philip W. Hedrick, Joel D. Parker

Joel D Parker

The evolutionary genetics of haplodiploids and X-linked genes share many features and are different from diploid (autosomal) genes in many respects. For example, the conditions for a stable polymorphism, the amount of genetic load, and the effective population size are all expected to be quite different between haplodiploids or X-linked genes and diploids. From experimental data, the genetic load for X-linked genes is much less than autosomal genes and appears less for haplodiploids than for diploids. The observed amount of molecular variation for haplodiploids is much less than that for diploids, even more so than predicted from the differences in ...


Signal Transduction: Rhomantic Interludes Raise Blood Pressure, Andrew P. Somlyo Oct 1997

Signal Transduction: Rhomantic Interludes Raise Blood Pressure, Andrew P. Somlyo

Jama S. Coartney

No abstract provided.


Iron Regulatory Protein 1 Is Not Required For The Modulation Of Ferritin And Transferrin Receptor Expression By Iron In A Murine Pro-B Lymphocyte Cell Line, Kevin Schalinske, Kenneth P. Blemings, Daniel W. Steffen, Opal S. Chen, Richard S. Eisenstein Sep 1997

Iron Regulatory Protein 1 Is Not Required For The Modulation Of Ferritin And Transferrin Receptor Expression By Iron In A Murine Pro-B Lymphocyte Cell Line, Kevin Schalinske, Kenneth P. Blemings, Daniel W. Steffen, Opal S. Chen, Richard S. Eisenstein

Kevin Schalinske

Iron regulatory proteins (IRPs) are cytoplasmic RNA binding proteins that are central components of a sensory and regulatory network that modulates vertebrate iron homeostasis. IRPs regulate iron metabolism by binding to iron responsive element(s) (IREs) in the 5* or 3* untranslated region of ferritin or transferrin receptor (TfR) mRNAs. Two IRPs, IRP1 and IRP2, have been identified previously. IRP1 exhibits two mutually exclusive functions as an RNA binding protein or as the cytosolic isoform of aconitase. We demonstrate that the BayF3 family of murine pro-B lymphocytes represents the first example of a mammalian cell line that fails to express ...


Acute Toxicity And Behavioral Effects Of Chlorpyrifos, Permethrin, Phenol, Strychnine, And 2,4-Dinitrophenol To 30-Day-Old Japanese Medaka (Oryzias Latipes), Steven P. Bradbury, Patricia J. Rice, Charles D. Drewes, Theresa M. Klubertanz, Joel R. Coats Apr 1997

Acute Toxicity And Behavioral Effects Of Chlorpyrifos, Permethrin, Phenol, Strychnine, And 2,4-Dinitrophenol To 30-Day-Old Japanese Medaka (Oryzias Latipes), Steven P. Bradbury, Patricia J. Rice, Charles D. Drewes, Theresa M. Klubertanz, Joel R. Coats

Steven P. Bradbury

Five chemicals with different modes of action were evaluated in laboratory studies to determine their acute toxicity (48-h median lethal concentration [LC50]) and behavioral effects on 30-d-old Japanese medaka (Oryzias latipes). The order of toxicity for these xenobiotics was permethrin > chlorpyrifos > 2,4-dinitrophenol (2,4-DNP) > strychnine > phenol. The 48-h LC50s were significantly different and ranged from 0.011 to 24.1 mg/L. In addition, chlorpyrifos and permethrin accumulated in the tissues of juvenile O. latipes. Observations of five behavioral/morphological responses, including changes in equilibrium, general activity, startle response, and morphology (e.g., hemorrhage and deformities) were used as ...


The Brain As A Symbol-Processing Machine., Armando F. Rocha Jan 1997

The Brain As A Symbol-Processing Machine., Armando F. Rocha

Armando F Rocha

The knowledge accumulated about the biochemistry of the synapsis in the last decades completely changes the notion of brain processing founded exclusively over an electrical mechanism, toward that supported by a complex chemical message exchange occurring both locally, at the synaptic site, as well as at other localities, depending on the solubility of the involved chemical substances in the extracellular compartment. These biochemical transactions support a rich symbolic processing of the information both encoded by the genes and provided by actual data collected from the surrounding environment, by means of either special molecular or cellular receptor systems. In this processing ...


Hadhramaut And The Hadhrami Diaspora: Problems In Theoretical History, Syed Farid Alatas Jan 1997

Hadhramaut And The Hadhrami Diaspora: Problems In Theoretical History, Syed Farid Alatas

farid alatas

If we understand history as a field constituted by a type of research and inquiry that concerns itself with human action in the past and is based on the interpretation of evidence, regardless of whether positivist or interpretive methods are used, then it can be said that historical works on Hadhramaut and its diaspora have been written. These works can be divided in broad terms into the two general categories of Arab and Western historiography. Nevertheless, in both cases, owing to certain theoret- ical problems that have beset these works, little progress has been made in the advancement of Hadhrami ...


Methods Of Identifying The Avian Repellent Effects Of A Compound And Methods Of Repelling Birds From Materials Susceptible To Consumption By Birds, Larry Clark Jan 1997

Methods Of Identifying The Avian Repellent Effects Of A Compound And Methods Of Repelling Birds From Materials Susceptible To Consumption By Birds, Larry Clark

Larry Clark

No abstract provided.


Isolation Of A Mannose-Binding And Ige- And Igm-Reactive Lectin From The Seeds Of Artocarpus Integer, Onn Haji Hashim Jan 1997

Isolation Of A Mannose-Binding And Ige- And Igm-Reactive Lectin From The Seeds Of Artocarpus Integer, Onn Haji Hashim

Onn Haji Hashim

A mannose-binding lectin, termed champedak lectin-M, was isolated from an extract of the crude seeds of champedak (Artocarpus integer). On gel filtration chromatography, the lectin eluted in a single peak at elution volumes corresponding to 64 kDa, SDS-PAGE showed the mannose-binding lectin to be composed of 16.8 kDa polypeptides with some of the polypeptides being disulphide-linked to give dimers. When tested with all isotypes of immunoglobulins, champedak lectin-M demonstrated a selective strong interaction with human IgE and IgM, and a weak interaction with IgA2, The binding interactions of lectin-M were metal ion independent. The lectin was also shown to ...


A Computationally-Based Hazard Identification Algorithm That Incorporates Ligand Flexibility. 1. Identification Of Potential Androgen Receptor Ligands, Steven P. Bradbury, Ovanes Mekenyan, Julian Ivanov, Stoyan Karabunarliev, Gerald T. Ankley, Walter Karcher Jan 1997

A Computationally-Based Hazard Identification Algorithm That Incorporates Ligand Flexibility. 1. Identification Of Potential Androgen Receptor Ligands, Steven P. Bradbury, Ovanes Mekenyan, Julian Ivanov, Stoyan Karabunarliev, Gerald T. Ankley, Walter Karcher

Steven P. Bradbury

To advance techniques for screening large data sets of diverse structures for toxicologically active compounds, an algorithm was developed that is not dependent upon a predetermined and specified toxicophore or an alignment of conformers to a lead compound. Instead, the approach provides the means to identify and quantify specific global and local stereoelectronic characteristics associated with active compounds through a comparison of energeticallyreasonable conformer distributions for specific descriptors. To illustrate the algorithm, the stereoelectronic requirements associated with the binding affinity of 28 steroidal and non-steroidal ligands to the androgen receptor were defined. Common ranges of interatomic distances, atomic charges, and ...


The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps Jan 1997

The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps

Douglas D. Stokke

The known effects of silvicultural practices on eastern black walnut (Juglans nigra L.) wood quality are reviewed. Since desirable quality differs from end user to end user, no specific recommendations are made.


Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek Jan 1997

Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek

Douglas D. Stokke

Many walnut plantation owners and woodworking hobbyists would like to process small quantities of walnut logs into lumber and discs for furniture and craft items. Various options exist for sawing, drying, and processing small diameter or short logs into lumber and cross-sectional discs. Portable band saws are a safe and inexpensive log breakdown option to commercial headsaw mills. Processing using the saw-dry-rip method will yield higher quantities of usable lumber from small diameter logs than the conventional saw-rip-dry method. Small quantities of lumber and discs can be inexpensively air dried under shelters or open sheds followed by approximately 15 to ...


Effects Of Elevated Co2 And Defoliation On Grasses: A Comparative Ecosystem Approach, Brian J. Wilsey, James S. Coleman, Samuel J. Mcnaughton Jan 1997

Effects Of Elevated Co2 And Defoliation On Grasses: A Comparative Ecosystem Approach, Brian J. Wilsey, James S. Coleman, Samuel J. Mcnaughton

Brian J. Wilsey

Three plant species from each of three grassland ecosystems were grown under elevated (700 mL/m3) and ambient (350 mL/m3) CO2 and were defoliated or left undefoliated to test whether species response to elevated CO2 and grazing is related to evolutionary grazing history or to mode of photosynthesis. The three ecosystems represented a tropical grassland dominated by C4 species (the Serengeti of Africa), a temperate grassland dominated by a mixture of C3 and C4 species (Flooding Pampa of South America), and a northern temperate grassland dominated by C3 species (Yellowstone National Park of North America). Plants were grown in ...


Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan Jan 1997

Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan

Douglas D. Stokke

Risks and uncertainties are prevalent in timber production due to the nature and length of the production process. This paper examines the volatility of timber prices and the effects of some economic uncertainties and risks such as fluctuations in timber prices and the interest rate on the economic returns of black walnut and red oak plantations. Historical patterns of timber prices for black walnut and oaks are investigated and compared with those of other timber species and stock price. The sensitivity of economic returns from black walnut and red oak plantations to changes in timber prices and the discount rate ...


Identification Of A Fish Host Of The Inflated Heelsplitter Potamilus Inflatus( Bivalvia: Unionidae) With A Description Of Its Glochidium, Kevin J. Roe, Andrew M. Simons, Paul Hartfield Jan 1997

Identification Of A Fish Host Of The Inflated Heelsplitter Potamilus Inflatus( Bivalvia: Unionidae) With A Description Of Its Glochidium, Kevin J. Roe, Andrew M. Simons, Paul Hartfield

Kevin J. Roe

A survey of the fishes of the lack Warrior River was undertaken to determine fish host(s) of the federally threatened inflated heelsplitter, Potamilus inflatus. Seven hundred-twenty individual fishes representing 30 species were examined; mussel glochidia were found on 10 individual fishes representing nine species. Potamilus inflatus glochidia were only found infesting one freshwater drum (Aplodinotus grunniens), which is concordant with previous findings for the genus Potamilus. The morphology of P. inflatus glochidia is described and compared to P. purpuratus.


The Theme Of "Relevance" In Third World Human Sciences, Syed Farid Alatas Dec 1996

The Theme Of "Relevance" In Third World Human Sciences, Syed Farid Alatas

farid alatas

The fact that the humanities and social sciences in developing societies generally originated in the West has raised the issue of the relevance of these arts and sciences to the needs and problems of Third World societies. This questioning of relevance has led, in turn, to the call for the indigenisation of knowledge in developing societies. While there has been a great deal of discussion on indigenisation, there has been little practice of indigenised humanities and social science. As a result, there are few examples of what indigenous knowledge constitutes from theoretical, methodological and empirical points of view. This paper ...


Quantitative Structure-Activity Relationships For Polychlorinated Hydroxybiphenyl Estrogen Receptor Binding Affinity: An Assessment Of Conformer Flexibility, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley Nov 1996

Quantitative Structure-Activity Relationships For Polychlorinated Hydroxybiphenyl Estrogen Receptor Binding Affinity: An Assessment Of Conformer Flexibility, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley

Steven P. Bradbury

A diverse group of xenobiotics has a high binding affinity to the estrogen receptor (ER), suggesting that it can accommodate large variability in ligand structure. Relationships between xenobiotic structure, binding affinity, and estrogenic response have been suggested to be dependent on the conformational structures of the ligands. To explore the influence of conformational flexibility on ER binding affinity, a quantitative structure—activity relationship (QSAR) study was undertaken with estradiol, diethylstilbestrol, and a set of polychlorinated hydroxybiphenyls (PCHBs) of environmental concern. Although the low-energy minima of the PCHB congeners suggested that interconversions among conformers were likely, the electronic parameters associated with ...


Pollen Dispersal In Low-Density Populations Of Three Neotropical Tree Species, Jason D. Nason, E. A. Stacy, J. L. Hamrick, S. P. Hubbell, R. B. Foster, R. Condit Aug 1996

Pollen Dispersal In Low-Density Populations Of Three Neotropical Tree Species, Jason D. Nason, E. A. Stacy, J. L. Hamrick, S. P. Hubbell, R. B. Foster, R. Condit

Jason D Nason

Studies of mating patterns of tropical trees, typically involving common species, have revealed that most species are outcrossed and that, in some cases, a significant reaction of outcross pollen moves long distances. We evaluated mating systems and effective pollen dispersal for three hermaphroditic insect-pollinated Neotropical tree species, Calophyllum longifolium, Spondias mombin and Turpinia occidentalis, all of which occurred at low adult densities at the study site. Mating patterns were estimated for each maternal tree within 84-ha populations of C. Longifoliuman d S. mombin in 1992 and 1993 and within a 50-ha population of T. occidentalis in 1993. Each population was ...


Bird Aversive Properties Of Methyl Anthranilate, Yucca, Xanthoxylum, And Their Mixtures, Larry Clark, Bruce Bryant, Igor Mezine Jan 1996

Bird Aversive Properties Of Methyl Anthranilate, Yucca, Xanthoxylum, And Their Mixtures, Larry Clark, Bruce Bryant, Igor Mezine

Larry Clark

We tested the bird aversive properties of methyl anthranilate, yucca extracts, and Xanthoxylum spp. extracts in one- and two-bottle drinking assays that used European starlings (Sturnus vulgaris). In one- and two-bottle tests, methyl anthranilate proved to be the more potent stimulus in producing an avoidance response. Starlings avoided consuming Xanthoxylum and yucca only in the two-bottle tests. Previous studies showed that yucca was a good adjuvant in stabilizing lipophilic compounds in water. Starlings did not avoid binary mixtures of methyl anthranilate and yucca differently from what would be expected if they were only responding to the solution's methyl anthranilate ...


Grazing Repellency Of Methyl Anthranilate To Snow Geese Is Enhanced By A Visual Cue, J. Russell Mason, Larry Clark Jan 1996

Grazing Repellency Of Methyl Anthranilate To Snow Geese Is Enhanced By A Visual Cue, J. Russell Mason, Larry Clark

Larry Clark

Methyl anthranilate (Rejex-It AG-36) is formulated as a commercial goose repellent. Frequent reapplications of this product are often necessary, and the cost/application is high ($300.00/ha). The present experiment tested the possibility that the repellency of methyl anthranilate might be enhanced by the addition of visual cues. Twelve 0.4 ha plots were assigned randomly to three treatment groups. Plots in the first group (n = 4) were sprayed with 10% Vapor Guard (an agrochemical adhesive). Plots in the second group (n = 4) were treated with a mixture of methyl anthranilate (3.4 kg/ha) and Vapor Guard. Plots ...


Avoidance Of Cabbage Fields By Snow Geese, J. Russell Mason, Larry Clark Jan 1996

Avoidance Of Cabbage Fields By Snow Geese, J. Russell Mason, Larry Clark

Larry Clark

now Goose activity levels were significantly less in cabbage fields than in control fields. Although the data do not unambiguously address the issue of sulfur repellency, we believe that the activity difference is consistent with avoidance of the former and not preference for the latter. Sulfurous volatiles were readily apparent to us during our visits to cabbage fields throughout the study period. Similar odors were not detected in control fields. If sulfurous volatiles were important, then avoidance could reflect some characteristic of the cover crop (e.g., unpalatability acquired through the absorption and translocation of degra­ dation products) or it ...


Degradation Studies Of The Non-Lethal Bird Repellent, Methyl Anthranilate, Eugeny Aronov, Larry Clark Jan 1996

Degradation Studies Of The Non-Lethal Bird Repellent, Methyl Anthranilate, Eugeny Aronov, Larry Clark

Larry Clark

Methyl anthranilate (MA), a food grade flavor and fragrance additive, has been reported to be an effective non-lethal bird repellent in a variety of situations. Despite the experimental success of MA, field studies have yielded widely differing levels of efficacy. Diminished efficacy in some field trials prob­ ably results from the failure of specific formulations to retain or protect the active ingredient under natural conditions. Therefore, a clearer understanding of the physical and chemical factors affecting the stability of MA is needed. We undertook a series of laboratory studies on hydrolysis, photolysis and microbial degradation of MA, the results of ...


Non-Mycorrhizal Uptake Of Amino Acids By Roots Of The Alpine Sedge Kobresia Myosuroides: Implications For The Alpine Nitrogen Cycle, Ted K. Raab, David A. Lipson, Russ K. Monson Jan 1996

Non-Mycorrhizal Uptake Of Amino Acids By Roots Of The Alpine Sedge Kobresia Myosuroides: Implications For The Alpine Nitrogen Cycle, Ted K. Raab, David A. Lipson, Russ K. Monson

Ted K. Raab

Non-mycorrhizal plants of the alpine sedge, Kobresia myosuroides , take up the amino acid glycine from nutrient solutions at greater rates than NO3- or NH4+. The amino acids glutamate and proline were also taken up at high rates. Total plant biomass was twice as high after 4 months of growth on glycine, compared to NH4NO3, with significant increases in both root and leaf biomass. By taking advantage of differences in the d13C signature of air in the growth chamber and the glycine used for growth, a two-member mixing model was used to estimate that a significant amount of the glycine was ...


Haploid Plant Regeneration From Anther Cultures Of Three North American Cultivars Of Strawberry (Fragaria X Ananassa Duch.), Henry R. Owen, A. Raymond Miller Jan 1996

Haploid Plant Regeneration From Anther Cultures Of Three North American Cultivars Of Strawberry (Fragaria X Ananassa Duch.), Henry R. Owen, A. Raymond Miller

Henry R. Owen

A study was conducted to maxmuze plant regeneration frequencies from cultured anthers of' Chandler', 'Honeoye', and 'Redchief strawberries (Fragaria x ananassa Duch.). A comparison of auxins (IAA, NAA), cytokinins (BA, BPA, KIN) and carbohydrates (sucrose, glucose, maltose) in MS medium showed that the highest shoot regeneration across cultivars (8%) occurred when using a medium containing 2 mgtl IAA, I mgtl BA, and 0.2 M glucose. A comparison ofMS, NN, and HI inorganic medium (a new formulation based on the anther culture literature) solidified with either agar or gellan gum and containing IAA, BA, and glucose, showed the highest shoot ...