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Ethylene Synthesis And Sensitivity In Crop Plants, Stephen P. Klassen, Bruce Bugbee

NASA

Closed and semi-closed plant growth chambers have long been used in studies of plant and crop physiology. These studies include the measurement of photosynthesis and transpiration via photosynthetic gas exchange. Unfortunately, other gaseous products of plant metabolism can accumulate in these chambers and cause artifacts in the measurements. The most important of these gaseous by products is the plant hormone ethylene (C2H4). In spite of hundreds of manuscripts on ethylene, we still have a limited understanding of the synthesis rates throughout the plant life cycle. We also have a poor understanding of the sensitivity of intact, rapidly growing plants to …

Reproductive Allocation And Survival In Grasshoppers: Effects Of Resource Availability, Grasshopper Density, And Parasitism, David Heath Branson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A major challenge in ecology is to understand intraspecific variation in life histories. Variation in resource availability can lead to differences in reproductive allocation and life histories. Grasshoppers are a good organism for the study of variation in life histories, since they exhibit life history plasticity in response to biotic and environmental factors. An optimality model for grasshoppers was developed that predicts optimal total allocation to reproduction and optimal effort-per-offspring as functions of resource availability and mortality. Relative allocation to reproduction is predicted to increase with resource availability, while relative allocation to survival declines. A resource-based trade-off between egg size …

Molecular Characterization Of Soil Ammonia-Oxidizing Bacteria Based On The Genes Encoding Ammonia Monooxygenase, Jose Javier Alzerreca

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ammonia-oxidizing bacteria (AOB) are chemolithotrophs that oxidize ammonia/ammonium to nitrite in a two-step process to obtain energy for survival. AOB are difficult to isolate from the environment and iso lated strains may not represent the diversity in soil. A genetic database and molecular tools were developed based on the ammonia monooxygenase (AMO) encoding genes that can be used to assess the diversity of AOB that exist in soil and aquatic environments without the isolation of pure cultures. The amo genes have excellent potential as molecular markers; since AMO is only found in the AOB and is essential for their metabolism, …

Insights, Spring, 1998, Utah State University

Discovery Magazine

Bi-annual alumni newsletter for the College of Science of Utah State University in Logan.

Factors Concerning The Conservation Of A Rare Shale Endemic Plant: The Reproductive Ecology And Edaphic Characteristics Of Penstemon Debilis (Scrophulariaceae), Amy L. Mcmullen

Biology

The management of a rare, edaphic endemic plant species requires an understanding of the ecological setting and processes that contribute to its restriction. Included in the ecological processes is a set of biotic characters associated with the reproductive ecology, including its breeding system, pollination vectors, and germination requirements. The geologic and soil setting of the plant must also be characterized in order to understand the plant's restriction to the substrate. These issues were addressed by this study of the rare endemic Penstemon debilis O'Kane and Anderson (Scrophulariaceae). Penstemon debilis consists of six populations that occur on talus slopes of the …

Microgravity Effects On Water Flow And Distribution In Unsaturated Porous Media, Scott B. Jones, Dani Or

Utah Space Grant Consortium

Several aspects of the physical processes of liquid flow and distribution within partially saturated porous media are altered in the reduced gravity conditions (microgravity) of orbiting spacecraft. The objectives of this study were to simulate and test measured flow and distribution in porous media from a microgravity environment using conventional capillary flow theory. Two past microgravity experiments studying water supply and uptake in porous media took place on a U.S. space shuttle, titled ASC-1, and on the Russian space station Mir, titled Greenhouse-2. Data from microgravity and ground experiments were simulated using similar physical flow models by elimination of the …

The Effects Of Temperature Regime And Food Availability On Growth Rates Of Young-Of-The-Year Colorado Squawfish (Ptychocheilus Lucius) In The Green River, Utah, Craig J. Schaugaard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of different daily temperature regimes and food availability on growth rates of Colorado squawfish (Ptychocheilus lucius) were determined using field and laboratory experiments. Daily temperature and food gradients were observed in river backwaters (important nursery habitat for juvenile Colorado squawfish). High fluctuating temperatures (± 5-8° C) were observed daily in the shallow, terminal ends of backwaters. Where backwaters were in contact with the river (mouth), daily temperature fluctuations decreased (± 2° C). Food availability also varied spatially between the mouth and end of each backwater. To test whether Colorado squawfish growth rates varied in different areas …

A Scanning Electron Microscopy Study Of Taxus Leaves As Related To Taxonomy, G.A. Strobel, W. M. Hess

Scanning Microscopy

Scanning electron microscopy, when applied to the surfaces of the needles of Taxus spp. (yew) revealed features that appear useful in the taxonomy of this tree species which yields the important anticancer drug, taxol. For instance, all of the four North American species have 3-5 rows of stomata on one-half of the abaxial leaf surface, whereas all of the others, including those from Europe and Asia, have 7-10 rows of stomata. The appearance of individual or fused papilliform epidermal cells and their arrangement on the leaf surface also is a feature that varies between species. Patterns of wax formation appeared …

Pre-Embedding Staining Of Single Muscle Fibers For Light And Electron Microscopy Studies Of Subcellular Organization, Evelyn Ralston, Thorkil Ploug

Scanning Microscopy

Skeletal muscle fibers are large, multinucleated cells which pose a challenge to the morphologist. In the course of studies of the distribution of the glucose transporter GLUT4, in muscle, we have compared different preparative procedures, for both light (LM) and electron microscopy (EM) immunocytochemistry. Here we show that pre-embedding staining of single teased fibers, or of single enzymatically dissociated fibers, has several advantages over the use of sections for observing discrete patterns that extend over long distances in the cells. We report on an optimization study carried out to establish fixation and permeabilization conditions for EM immunogold labeling of the …

X-Ray Microscopy: Preparations For Studies Of Frozen Hydrated Specimens, A. Osanna, C. Jacobsen, A. Kalinovsky, J. Kirz, J. Maser, S. Wang

Scanning Microscopy

X-ray microscopes provide higher resolution than visible light microscopes. Wet, biological materials with a water thickness of up to about 10 μm can be imaged with good contrast using soft X-rays with wavelengths between the oxygen and carbon absorption edges (at 24 and 43 Å). The Stony Brook group has developed and operates a scanning transmission X-ray microscope (STXM) at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The microscope is used for imaging with a current resolution of 50 nm, and for elemental and chemical state mapping.

Radiation damage imposes a significant limitation upon high resolution X-ray …

Reproductive Ecology, Population Genetics, And Clonal Distribution Of The Narrow Endemic: Mirabilis Macfarlanei (Nyctaginaceae), Jennifer L. Barnes

Biology

I examined the reproductive biology and population genetics of the narrow endemic, Mirabilis macfarlanei (Nyctaginaceae) Constance and Rollins, from the Snake and Salmon Rivers in Idaho and Oregon. The results of this study provide further evidence for the proposed effects of rarity on plant reproductive systems and population genetics. Breeding system results indicated that M. macfarlanei is self-compatible, but requires a pollen vector for fertilization. Seed set was not pollen limited, but may be resource limited during others. The major floral visitors were long-tongued bees such as Anthophora spp. and Bombus spp., unlike other species of Mirabilis, which are …

Imaging Molecular Structure Of Channels And Receptors With An Atomic Force Microscope, Ratneshwar Lal

Scanning Microscopy

Biological membranes contain specialized protein macromolecules such as channels, pumps and receptors. Physiologically, membranes and their constituent macromolecules are the interface surfaces toward which most of the regulatory biochemical and other signals are directed. Yet very little is known about these surfaces. The structure of biological membranes has been analyzed primarily using imaging techniques that are limited in their resolution of surface topology. An atomic force microscope (AFM) developed by Binnig, Quate and Gerber, can image molecular structures on specimen surfaces with subnanometer resolution, under diverse environmental conditions. Also, AFM can manipulate surfaces with molecular precision: it can nanodissect, translocate, …

Atomic Force Microscopy Of Nucleoprotein Complexes, Y. L. Lyubchenko, B. L. Jacobs, S. M. Lindsay, A. Stasiak

Scanning Microscopy

Recent data on the AFM studies of nucleoprotein complexes of different types are reviewed in this paper. The first section describes the progress in the sample preparation methods for AFM studies of nucleic acids and nucleoprotein complexes. The second part of this paper reviews AFM data on studies of complexes of DNA with regulatory proteins. These studies include two different types of DNA distortion induced by proteins binding: local bending of DNA at sites of protein binding and formation of large loops due to protein-protein interactions between molecules bound to distant sites along the DNA molecules (DNA looping). The prospects …

The Principles Of Proton Probe Microanalysis In Biology, G. J. F. Legge, M. Cholewa

Scanning Microscopy

The proton microprobe, more correctly described as an ion microprobe which operates at MeV energies, complements its parent instrument the electron microprobe. This paper compares the basic principles and performance of the two instruments and relates the evolution of biological analysis on such ion microprobes to that on electron microprobes, covering the development of sample handling techniques and of data handling techniques and comparing beam damage studies. The paper describes the variety of techniques available to the ion microprobe - the initial techniques of Energy Dispersive X-ray analysis, Rutherford Back Scattering and Nuclear Reaction Analysis and the rapid evolution of …

Autoantibodies To Neurofilament Proteins In Autistic Subjects, Rex Elbert Averett

Biology

Immunological studies of autistic subjects have revealed certain features that are also found in subjects with other autoimmune diseases. Autoantibodies to neural tissue antigens and neurofilament proteins have been implicated in several disease conditions (e. g. autism, Alzheimer's disease, amyotrophic lateral sclerosis, retinitis pigmentosa, spongiform virus encephalopathies, and perhaps other neurological disorders). Sera from patients with these diseases have been examined with immunoblotting, immunofluorescence microscopy, and enzyme-linked-immunosorbent assay and each has found antibodies that react with proteins of neurofilaments. At present, the etiology and pathological mechanisms of most of these diseases are unknown. This study was undertaken to investigate the …

The Effect Of Climate And Spittlebug (Aeneolamia Albofasciata) On Buffelgrass (Cenchrus Ciliaris L.) Productivity In The Sonoran Desert, Martha H. Martin-Rivera

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I conducted field studies during 1984-1988 to determine how (1) precipitation amount and distribution affect buffelgrass [Cenchrus ciliaris L. (Link) l productivity, (2) summer rainfall amount and distribution and temperature influenced the spittlebug (Aeneolamia albofasciata Lalleman) life cycle, and (3) summer burning affects spittlebug densities and buffelgrass productivity.

Experiment I was conducted from 1985 through 1988. Forage samples collected at 15-day intervals were separated into live, recent-dead standing, old-dead standing, and litter. There was a positive relationship between the summer precipitation and the live biomass. Recent-dead standing and old-dead standing decomposed during the summer, fall, or spring.

Experiment …

Quantitative Dark-Field Mass Analysis Of Ultrathin Cryosections In The Field-Emission Scanning Transmission Electron Microscope, S. Brian Andrews, Roger A. Buchanan, Richard D. Leapman

Scanning Microscopy

The availability of a cryotransfer stage, highly efficient electron energy loss spectrometers, and ultrathin-window energy-dispersive x-ray spectrometers for the VG Microscopes HB501 field-emission scanning transmission electron microscope (STEM) provides this instrument with the potential for high resolution biological microanalysis. Recent technical advances offer cryosections that are thin enough to take advantage of the analytical capabilities of this microscope. This paper first discusses the quantitative characterization of freeze-dried, ultrathin cryosections of directly frozen liver and brain by low-dose dark-field STEM imaging. Such images reveal high-quality sections with good structural detail, mainly due to reduced preparation artifacts and electron beam damage. These …

Analysis Of High Quality Monatomic Chromium Films Used In Biological High Resolution Scanning Electron Microscopy, Robert P. Apkarian

Scanning Microscopy

During the recent employment of field emission (FE) in-lens scanning electron microscopes (SEMs), refractory metal deposition technology has co-evolved to provide enhanced contrast of 1-10 nm hydrocarbon based biological structures imaged at high magnifications (> 200,000 times). Pioneer development employing the Penning sputter system in a high vacuum chamber proved that imaging of chromium (Cr) coated biological specimens contained enriched secondary electron (SE)-(I) contrasts. Single nanometer size fibrillar and particulate ectodomains within the context of complex biological membranes were accurately imaged without significant enlargement using the high resolution SE-I mode (HRSEM). This paper reports the transmission electron microscopy (TEM) testing …

The Preparation Of Cultured Cells For X-Ray Microanalysis, Alice Warley

Scanning Microscopy

X-ray microanalysis of cells in culture is being used increasingly for the study of relationships between element (ion) content and cell function. There is, however, no one single method which can be used for the preparation of all different cell types for study by microanalysis. Cells in suspension are usually concentrated by centrifugation, before cryofixation, cryosectioning, and freeze drying. On the other hand cells grown as monolayers are more often studied as whole cell mounts, which are washed to remove the external medium before cryofixation and freeze drying. The alternative approach, sectioning of cell monolayers is rarely used. Some of …

Ion Microscopy In Biology, George H. Morrison, Isabelle Gay, Subhash Chandra

Scanning Microscopy

Ion microscopy, a mass spectrometry based isotopic imaging technique, is uniquely suited for ion transport-related problems in biological systems. Due to its high sensitivity, it can image the transport and distribution of both major and minor elements (isotopes) at subcellular resolutions. The images of major elements such as K, Na, Cl, etc., can be viewed directly and recorded in real-time from the microchannel plate-fluorescent screen detector of the instrument. The low concentration physiologically important elements, such as Ca, need about one minute of integration for good quality imaging. The isotopic imaging capability of ion microscopy provides a unique approach for …

Mechanisms Of Hard-To-Cook Defect In Cowpeas: Verification Via Microstructure Examination, Keshun Liu, Yen-Con Hung, R. Dixon Phillips

Food Structure

It has been hypothesized that part of the hard-to-cook (HTC) defect in cowpeas is due to decreases in solubility and thermal stability of intracellular proteins during storage since coagulated proteins would limit water to starch and prevent full swelling during cooking. To verify this hypothesis, effects of soaking and heating temperature on texture, water absorption, protein water extractability and microstructure of control and HTC cowpea seeds (aged or treated) were studied. Scanning electron microscopy showed no structural difference between dry control and dry aged seeds. However, after soaking, in contrast to the control, aged seeds exhibited a coarse protein matrix …

A Review Of Graphite And Gold Surface Studies For Use As Substrates In Biological Scanning Tunneling Microscopy Studies, Carol R. Clemmer, Thomas P. Beebe Jr.

Scanning Microscopy

The current status of biological Scanning Tunneling Microscopy (STM) investigations and the importance of using a well-characterized substrate are discussed. The findings of over two years of experiments and over 1,000 images obtained on gold substrates prepared by a variety of different methods are statistically summarized and compared to a very flat reference substrate, highly oriented pyrolytic graphite (HOPG). In an effort to begin to corroborate STM results with those obtained from other more established techniques, the results of Auger Electron Spectroscopy (AES) and Electron Spectroscopy for Chemical Analysis (ESCA) of biomolecular STM samples are presented.

Integrated Single Crystal Detector For Simultaneous Detection Of Cathodoluminescence And Backscattered Electrons In Scanning Electron Microscopy, Rudolf Autrata, Josef Jirák, Jiří Špinka, Otakar Hutař

Scanning Microscopy

The design of the majority of the available high efficiency cathodoluminescence (CL) detection systems allows the secondary electron (SE) and backscattered electron (BSE) image modes to be detected simultaneously to a limited degree only. The described CL-BSE detector is based on the single crystal YAG scintillator shaped as a spherical mirror which reflects photons emitted from the CL specimen and focuses them on to the entrance surface of a fibre optic light guide connected to the photomultiplier tube (PMT I). The backscattered electrons emitted from the CL specimen move through the reflecting layer of the mirror into the YAG scintillator …

A Brief Introduction To Aims And Methods For Image Processing Of Electron Micrographs Of Biological Specimens, Murray Stewart

Scanning Microscopy

A common problem with electron micrographs of biological objects is that fine details are usually faint and, moreover, tend to be obscured by background noise from stain and support film. Filtering is a useful way to improve the signal-to-noise ratio and is particularly important when trying to detect small changes (conformational or due to labelling) or when examining frozen hydrated objects, where the statistical definition of the image has been reduced because of the low-dose conditions needed to prevent radiation damage. Filtering can also be used to address the superposition effects that result from the large depth of focus of …

Microbeam Studies Of The Sensitivity Of Structures Within Living Cells, L. A. Braby

Scanning Microscopy

Determining the biological effects of low doses of radiation with high linear energy transfer (LET) is complicated by the stochastic nature of charged-particle interactions. Populations of cells exposed to very low radiation doses contain a few cells which have been hit by a charged particle, while the majority of the cells receive no radiation damage. At somewhat higher doses, a few cells receive two or more events. Because the effects of damage produced by separate events can interact in the cell, we have had to make assumptions about the nature of these interactions in order to interpret the results of …

A Review Of Scanning Tunneling Microscope And Atomic Force Microscope Imaging Of Large Biological Structures: Problems And Prospects, B. L. Blackford, M. H. Jericho, P. J. Mulhern

Scanning Microscopy

The application of the scanning tunneling microscope (STM) and the atomic force microscope (AFM) to the study of small biological molecules, such as DNA and smaller molecules, has received considerable attention in the literature. This paper reviews STM and AFM studies of larger biological structures such as bacterial membranes, bacteriophages, viruses, antibodies, etc. The problems encountered in these applications are emphasized, with particular reference to the unknown conduction mechanism, tip-sample interaction forces, and tip-sample convolution artifacts in the images. The latter problem is illustrated by new results from IgG antibody complexes attached to a bacterial sheath layer. A new conduction …

Terminal Differentiation Of Human Fibroblasts Is Induced By Radiation, H. Peter Rodemann, Hans-Peter Peterson, Karla Schwenke, K. -Hartmut Von Wangenheim

Scanning Microscopy

In order to analyze the effect of various kinds of radiation on the terminal differentiation processes of fibroblasts in culture, both human skin and lung fibroblasts were irradiated with electromagnetic non ionizing as well as ionizing radiation in clonal and sparse mass culture systems. As analyzed by cell biological (cell type frequencies), biochemical (collagen synthesis) and molecular markers (expression of protein PIVa) human skin and lung fibroblasts are induced to differentiate prematurely into terminal postmitotic cells. Thus, both electromagnetic and ionizing radiation induce terminal differentiation in cultured cells. These data add some new aspects for the interpretation of radiation effects …

Ted Hall And The Science Of Biological Microprobe X-Ray Analysis: A Historical Perspective Of Methodology And Biological Dividends, Brij L. Gupta

Scanning Microscopy

This review surveys the emergence of electron probe X-ray microanalysis as a quantitative method for measuring the chemical elements in situ. The extension of the method to the biological sciences under the influence of Ted Hall is reviewed. Some classical experiments by Hall and his colleagues in Cambridge, UK, previously unpublished, are described; as are some of the earliest quantitative results from the cryo-sections obtained in Cambridge and elsewhere. The progress of the methodology is critically evaluated from the earliest starts to the present state of the art. Particular attention has been focused on the application of the method in …

Surface Modification Of Polymers To Permit Endothelial Cell Growth, C. James Kirkpatrick, Detlef Mueller-Schulte, Marc Roye, Guenter Hollweg, Claudia Gossen, Horst Richter, Christian Mittermayer

Cells and Materials

The interaction between endothelial cells (EC) and polymers has become relevant to medicine as a result of attempts to improve the biocompatibility of vascular prostheses. In man, endothelialization is minimal, so that vascular surgeons have attempted to pre-seed vascular grafts with autologous EC. The poor results of EC seeding of commonly used materials for vascular grafts, such as expanded polytetrafluoroethylene (ePTFE) or woven polyester (Dacron) has led to attempts to modify the surface of these and other polymers. Three principal modification techniques have been employed : 1. adsorption of bioactive molecules from applied solutions. Examples are fibronectin, collagen types I …

Characterization Of The Plasmid Dgp1 From The Cellular Slime Mold Dictyostelium Giganteum, Yizhong Yin

Biology

While nuclear-associated DNA plasmids are very rare in eukaryotic organisms, cellular slime molds of the genus Dicytostelium harbor many of them. The Dgp1 plasmid is one carried by Dictyostelium giganteum strain DG6.1. A restriction endonuclease site map of Dgp1 has been produced. The GC content of the restriction site sequences was found to be 42%, which closely matches the typical GC content of Dictyostelium coding sequences. Micrococcal nuclease digestion demonstrated that this plasmid has a typical Dictyostelium chromatin structure indicating its nuclear location. The stability of the Dgp1 DNA sequence when cloned in several Escherichia coli vectors as well as …