Digital Commons Network^™

Ultrastructural Changes Of The Vestibular Sensory Organs After Streptomycin Application On The Lateral Canal, Kwang-Sun Lee, Robert S. Kimura

Scanning Microscopy

Early changes in the vestibular sense organs resulting from the application of a streptomycin sulfate soaked Gelfoam® pledget on the fenestra of the lateral semicircular canal were studied by transmission and scanning electron microscopy. Three days after the application, lesions were present in the central part of the lateral crista. The type I sensory cells were more affected than the type JI cells. These sensory cells showed mitochondrial swelling, cytoplasm protrusion at the cell apex, inclusion of multiple vacuoles, fusion or loss of stereocilia, and pyknotic nuclei. Seven days after the drug application, the sensory cell damage extended to all …

Thorn-Like Prickles And Heterophylly In Cyanea: Adaptations To Extinct Avian Browsers On Hawaii?, T. J. Givnish, K. J. Sytsma, James F. Smith, W. J. Hahn

Biology Faculty Publications and Presentations

The evolution of thorn-like structures in plants on oceanic islands that lack mammalian and reptilian herbivores is puzzling, as is their tendency toward juvenile-adult leaf dimorphism. We propose that these traits arose in Cyanea (Campanul) on Hawaii as mechanical and visual defenses against herbivory by flightless geese and goose-like ducks that were extirpated by Polynesians within the last 1600 years. A chloroplast DNA phylogeny indicates that thorn-like prickles evolved at least four times and leaf dimorphism at least three times during the last 3.7 million years. The incidence of both traits increases from Oahu eastward toward younger islands, paralleling the …

Altering The Rna Binding Specificity Of A Translational Repressor, F Lim, Marc Spingola, D Peabody

Biology Department Faculty Works

The coat proteins of RNA phages MS2 and GA are specific RNA-binding proteins which function to encapsidate viral RNA and to translationally repress synthesis of the viral replicase. The two proteins have highly homologous amino acid sequences, yet they show different RNA binding specificities, recognizing RNA stem-loop structures which differ primarily in the nucleotide sequences of their loops. We sought to convert MS2 coat protein to the RNA binding specificity of GA through the introduction of GA-like amino acid substitutions into the MS2 coat protein RNA-binding site. The effects of the mutations were determined by measuring the affinity of the …

Light Element X-Ray Microanalysis In Biology, A. T. Marshall

Scanning Microscopy

It is shown that both qualitative and quantitative light element X-ray microanalysis of biological samples is feasible. These analyses were carried out using ultrathin window (UTW) detectors. Quantitative analysis yields a total element analysis with H estimated by difference or "guesstimated". Comparison with calculated concentrations, or concentrations obtained by chemical analysis, shows that X-ray microanalysis of sections, by the peak to continuum ratio model, give sufficiently accurate results for biological purposes.

The measurement of O concentrations to yield water content is carried out using x-ray imaging techniques, so that the distribution of heavier elements can be spatially related to water …

Effect Of Urinary Macromolecules And Chondroitin Sulphate On Calcium Oxalate Crystallization In Urine, A. L. Rodgers, D. Ball, W. Harper

Scanning Microscopy

After filtration and ultrafiltration (10 kD) of 24 hour urine specimens from 12 healthy male subjects, calcium oxalate crystallization was induced in the filtered (FILTD) and ultrafiltered (UF) fractions by administration of a sodium oxalate load. In addition crystallization was also induced in UF fractions to which physiological quantities of chondroitin sulphate (CHON) had been added (UF + CHON). The rate of calcium oxalate crystallization was determined by measuring the rate at which turbidity increased. Crystal numbers and sizes were measured with a Malvern particle size analyzer and by scanning electron microscopy.

Crystallization rates, crystal numbers and crystal sizes were …

Improvements In Biological X-Ray Microanalysis: Cryoembedding For Specimen Preparation And Multivariate Statistical Analysis For Data Interpretation, C. Quintana, N. Bonnet

Scanning Microscopy

For biological X-ray microanalysis, cryoembedding (CE) combined with cryofixation (CF) and cryodehydration (CD) was already proposed as an alternative method to freeze-dried cryosections in 1984 by Wroblewski and Wroblewski. CD by freeze-drying (FD) is usually recommended because it provides better retention of diffusible elements. CD by freeze-substitution (FS) has the advantage of being simpler, giving more reproducible preservation of ultrastructure and causing fewer problems for resin infiltration. We have increased the retention of diffusible elements by using home-made devices for CS and CE in the new Lowicryl KllM and HM23 resins. These resins allow samples to be kept at a …

Critical Point Mounting Of Kinetoplast Dna For Atomic Force Microscopy, T. Thundat, R. J. Warmack, D. P. Allison, K. B. Jacobson

Scanning Microscopy

Atomic force microscope (AFM) images of intact kinetoplast DNA were obtained from samples prepared utilizing critical point drying. These images are compared with AFM images obtained using conventional methods for DNA deposition. Although the images obtained on chemically pretreated mica show more details than on unmodified mica, images obtained with critical point drying were superior. Kinetoplast networks with expected sizes and structures were routinely observed with critical point drying. The resolution of individual strands of DNA was greatly improved, and image artifacts associated with air dried samples were eliminated. Samples prepared using mildly sonicated kinetoplast DNA show isolated minicircles.

Signal And Image Manipulation In Microanalysis, P. W. Hawkes

Scanning Microscopy

Scanning electron microscopes, and transmission instruments equipped for EELS, generate a host of signals and hence of images from each pixel of the specimen. Numerous ingenious ways of coping with this multiplicity of information, which may be very different in character, have been devised, but no detailed study has yet been made of the appropriate mathematical structure, with the aid of which all this information could be manipulated reasonably easily.

One such structure falls within the subject that has come to be known as Image Algebra, the principal attraction of which is that we deal directly with entire images …

Standards For X-Ray Microanalysis Of Calcified Structures, J. A. Lopez-Escamez, A. Campos

Scanning Microscopy

The ability of electron probe X-ray microanalysis (EPMA) to solve biological problems often depends on the use of a quantitative approach. EPMA allows the quantitative determination of chemical elements of biological materials by using reference standards which resemble the specimen in the mode of interaction with the electron beam. Although there is a large experience in the quantification of elements in biological thin specimens, experience with standards for X-ray microanalysis of bulk specimens is limited, especially for calcified structures where the density of the specimen is difficult to estimate. The quality of the results in EPMA depends on obtaining accurate …

Phylogenetic Analysis Of Segment 10 From African Horsesickness Virus And Cognate Genes From Other Orbiviruses, Rafael O. De Sá, Marla Zellner, Marvin J. Grubman

Biology Faculty Publications

Utilizing the reverse transcriptase-polymerase chain reaction (RT-PCR) procedure, we have synthesized full-length copies of segment 10 from African horsesickness virus (AHSV) serotypes 1,4 and 8. The genes were cloned, sequenced and compared with the sequence of the cognate gene from AHSV serotypes 3 and 9. Sequences were analyzed to assess evolutionary relationships among serotypes using cladistics. Based on this analysis the data support a close relationship between serotypes 4 and 9 and between serotypes 1 and 8 and a closer relationship of serotype 3 to the 4 and 9 group.

Environmental Scanning Electron Microscope Examination Of Paper In High Moisture Environment: Surface Structural Changes And Electron Beam Damage, Päivi Forsberg, Pierre Lepoutre

Scanning Microscopy

Supercalendered and coated papers (SC and LWC) were examined using an environmental scanning electron microscope (ESEM). Moderate structural surface changes were observed as water condensed on the surface in a high moisture environment. The changes were fully or partially reversible depending on the sample origin. A wide range of contact angles could be observed when condensing water on uncoated wood fibers. While there was no visible indication of irradiation damage on the commercial paper samples examined nor on mechanical pulp fibers, attempts to look at chemical pulp fibers during wetting to examine fiber swelling were unsuccessful because of very rapid …

X-Ray Microanalysis Of Endocrine, Exocrine And Intestinal Cells And Organs In Culture: Technical And Physiological Aspects, Romuald Wróblewski, Joanna Wroblewski

Scanning Microscopy

In the present study methods for preparation of cultured cells and organ cultures for analytical electron microscopy are investigated. These methods allow qualitative and quantitative analysis of mobile ions in combination with biochemical or morphological studies. Cultured cells can be easily prepared for analytical microscopy and therefore use of in vitro systems for X-ray microanalysis has increased over the last few years. Two major, anhydrous preparation techniques, by which loss or redistribution of ions is minimized, were used: (1) Cells were cryosectioned and analysis carried out on freeze-dried sections obtained from frozen cell monolayers, pelleted cells or organ cultures. (2) …

Microvascular Pattern Of The Retina In The Japanese Monkey (Macaca Fuscata Fuscata), Shigenori Okada, Yoshikuni Ohta

Scanning Microscopy

The microvascular architecture of the retina in the Japanese monkey was revealed using scanning electron microscopy of microvascular corrosion casts.

At the optic nerve disc, the central retinal artery radiated to four primary retinal arterioles: the superior and inferior temporal arterioles and superior and inferior nasal arterioles. A dense retinal capillary network showed regional differences in density. The capillary networks observed were divided in four parts: the optic nerve disc, macula, equator, and ora serrata. At the optic nerve disc, the network was a multi-laminar structure containing the radial peripapillary capillaries in parallel with the nerve fibers at the innermost …

Plasmon Effects In The Particle-Induced Kinetic Electron Emission From Solids, Max Rösler

Scanning Microscopy

Starting from a microscopic description of the particle-induced kinetic electron emission based on the transport equation formalism, the role of different excitation and scattering mechanisms is investigated. Especially, the excitation of electrons by decay of plasmons generated by the impinging particle results in an important contribution to the electron yield. In the case of ion-induced kinetic electron emission, the special features of the energy distribution of emitted electrons are related to the plasmon damping and the plasmon dispersion. In order to describe the available experimental results on nearly-free-electron metals (Al,Mg) in a consistent way, plasmon effects must be taken into …

Induction Of Selective Inner Hair Cell Damage By Carboplatin, S. Takeno, R. V. Harrison, R. J. Mount, M. Wake, Y. Harada

Scanning Microscopy

Carboplatin (diammine [1,1 cyclobutane dicarboxylato (2)-0,0'] platinum) is an anti-cancer agent which can be toxic to the inner ear. We have explored the nature of this ototoxicity in the chinchilla. In this species, initial degenerative changes appear to be restricted to the inner hair cell (IHC) regions of the organ of Corti. This finding is intriguing and unusual since all other known ototoxic drugs, such as aminoglycosides, are predominantly associated with outer hair cell damage.

In the present study, the mechanism of ototoxicity was investigated by comparing two different routes of carboplatin administration. Carboplatin was administered either intravenously (i.v.) or …

The Herpes Simplex Virus Thymidine Kinase Gene As A Conditional Negative-Selection Marker Gene In Arabidopsis Thaliana, Mihály Czakó, László Márton

Faculty Publications

The human herpes simplex virus thymidine kinase type 1 gene (HSVtk) acts as a conditional lethal marker in mammalian cells. The HSVtk-encoded enzyme is able to phosphorylate certain nucleoside analogs (e.g. ganciclovir, an antiherpetic drug), thus converting them to toxic DNA replication inhibitors. The utility of HSVtk as a conditional negative-selection marker was explored in Arabidopsis thaliana (L.) Heynh. HSVtk was introduced into Arabidopsis by Agrobaderium-mediated transformation. Transgenic plants were morphologically indistinguishable from wild type and exhibited normal fertility. Canciclovir at lO^-5to 10^-4 M drastically reduced shoot regeneration on transgenic, HSVtk* root explants …

Effects Of Competition And Predation On Prothonotary Warblers And House Wrens Nesting In Eastern Iowa, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

In a fragmented midwestern floodplain forest, a small Prothonotary Warbler (Protonotaria citrea) population experienced high competition with House Wrens (Troglodytes aedon) and mammalian nest predation in 1988-89. Despite the provision of 3 types of nest boxes and higher water levels, Prothonotary Warblers did not nest successfully and decreased in the fragmented forest in 1990-91. House Wrens used >90% of the nest boxes in both years. Wren territories doubled within the nestbox area, while remaining constant on an unmanipulated area. In contrast, a larger warbler population had high nesting success during 1990-91 in a relatively unfragmented, wetter forest tract. Such forests, …

A Physical Map Of The Klebsiella Pneumoniae M5a1 Genome, Alexandrine Randriamahefa

Loma Linda University Electronic Theses, Dissertations & Projects

Klebsiella pneumoniae is an enteric opportunistic pathogen which commonly causes pulmonary, urinary tract and kidney infections. It has also been widely used for the study of nitrogen fixation. In this study, a macrorestriction map of K. pneumoniae M5a1 chromosomal DNA was constructed using pulsed field gel electrophoresis (PFGE) and Southern hybridization techniques. The genome DNA was digested with two rare cutting restriction enzymes (XbaI and BlnI) and the genome size was estimated from the sum of the fragment sizes as 5,121 Kb (+2.8%). A tentative order of fragments was deduced using Southern hybridization with purified restriction fragments. …

Optimal Freeze-Drying Of Cryosections And Bulk Specimens For X-Ray Microanalysis, L. Edelmann

Scanning Microscopy

Electron microscopic investigations of rapidly frozen specimens of striated muscle, either frozen-hydrated or obtained after different dehydration procedures, have shown that the subcellular distribution of the main cellular cation K⁺ or its surrogates Rb⁺, Cs⁺, or Tl⁺ does not follow the water distribution but follows certain proteins. Conflicting results obtained by X-ray microanalysis of freeze-dried cryosections are explained by showing that freeze-drying of bulk specimens and cryosections must be carried out for rather long periods at low temperature in order to avoid severe shrinkage and ion redistribution artefacts. Proposals for future freeze-drying studies are …

Study Of Existing Information Concerning Water Quality Within Lake Mead, Vicki Scharnhorst, Southern Nevada Water Authority

Publications (WR)

The purpose of Task 010A15M of the Southern Nevada Water Authority (SNWA) Treatment and Transmission Facility (TTF) contract is to conduct a study of existing information concerning water quality within Lake Mead and identify additional water quality studies that are needed to supplement existing data. The objective of this task is not to discuss treatability of the raw water source; this is addressed by Task 010A18M, "Define Water Treatment Requirements." In addition, a narrative on the effect of pending Safe Drinking Water Act amendments and a determination of treated water quality goals is included in Task 010A16M, "Review Safe Drinking …

Ultrastructural Alterations Of Golgi Apparatus In The Nerve Cells Of Cerebral Cortex In Human Hydrocephalus. A Qualitative Study Using Cortical Biopsies, Orlando J. Castejon, Melecio Diaz, Consuelo Valero

Scanning Microscopy

Cortical biopsies of 17 patients with clinical diagnosis of hydrocephalus and associated pathology were examined in the transmission electron microscope. Moderately and severely edematous neurons showed relevant structural changes of the Golgi apparatus consisting of either discrete or marked dilation, fragmentation, and partial disappearance of Golgi stacked cisternae. In Arnold-Chiari malformation small Golgi complexes of vesicular type and atrophic changes were observed in severely edematous neurons. The microtubules appeared intact, suggesting differential response between Golgi complex and microtubules. Atrophic changes of the Golgi complex coexisted with degenerated presynaptic endings.

Ultrastructural Observations Of The Argonaut Shell, P. R. Mitchell, P. P. Phakey, W. A. Rachinger

Scanning Microscopy

An examination of the ultrastructure of the shell of the cephalopod Argonauta Nodosa was carried out using scanning electron microscopy, transmission electron microscopy and polarised light microscopy. The structure of the Argonaut shell was found to consist of an inner and outer prismatic layer separated by a thin central zone which was sparsely occupied by spherulitic crystals. Fluctuations in the width and porosity of the central zone resulted in changes in the shell's opacity and gave rise to the fibrous lines visible in the structure. The central zone was the region of initial growth and was the nucleating point for …

Recovery Of Marsh Vegetation At Malheur Lake Following An Extended Flood, Sherry Vlasta Spencer

Dissertations and Theses

Water levels of Malheur Lake in southeastern Oregon fluctuate widely with seasonal and cyclic climatic changes. Seven years of severe flooding from 1978 to 1984 produced the highest water levels in recorded history and covered almost all marsh vegetation. Seven years of drought followed the flooding, and by 1992 the water level had dropped to the lowest point in nearly 60 years. A survey of vegetation colonizing the lakeshore as flood water receded was conducted from 1989 to 1992 to describe the reestablishment of marsh vegetation. Six transects were placed in three different ecological units of the lake. Frequency and …

Biological Electron Energy Loss Spectroscopy In The Field-Emission Scanning Transmission Electron Microscope, R. D. Leapman, S. Q. Sun, J. A. Hunt, S. B. Andrews

Scanning Microscopy

The dedicated scanning transmission electron microscope (STEM) combined with parallel electron energy loss spectroscopy (EELS) provides a very sensitive means of detecting specific elements in small structures. EELS is more sensitive than optimized energy-dispersive X-ray spectroscopy by a factor of about three for calcium. Measurement of such low concentrations requires special processing methods such as difference-acquisition techniques and multiple least squares procedures for fitting reference spectra. By analyzing data recorded at each pixel in a spectrum-image it is possible to map quantitatively the elemental distributions in a specimen. It is possible to prepare cryosections that are sufficiently thin to avoid …

Electron Probe X-Ray Microanalysis Of Epithelial Cells: Aspects Of Cryofixation, Karl Zierold, Hartmut Hentschel, Frank Wehner, Armin Wessing

Scanning Microscopy

Content and distribution of diffusible ions in epithelial cells were studied by scanning transmission electron microscopy and energy dispersive electron probe X-ray microanalysis of freeze-dried cryosections from trout kidney, rat liver and Malpighian tubules of Drosophila larvae. Cryofixation of small excised kidney and liver samples by rapid immersion into liquid propane resulted in intracellular K/Na-ratios < 1. In contrast, K/Na-ratios > 7 were obtained after in situ cryofixation by means of a cryopunching device which allows tissue pieces to be frozen during excision from the intact organ. Isolated hepatocytes cryofixed in a small droplet of culture medium had a K/Na-ratio of 3.7. After culturing the hepatocytes, …

Radiation-Induced Fibrosis: The Structure/Function Relationship, J. C. Murray

Scanning Microscopy

Fibrosis is a frequent complication of therapeutic radiation delivered to organ sites such as the thorax and pelvic region. We investigated the relationship between function, and biochemical and structural changes in the lung and colon of CBA mice irradiated with 240 kV X-rays. Progressive changes in lung function, as evidenced by increased breathing rates were observed out to 6 months post-irradiation. Biochemical studies demonstrated increased metabolism (synthesis and breakdown) of collagen around 6 months after irradiation, but provided no evidence of net collagen accumulation. Analysis of collagen isotypes revealed a slight increase in the ratio of types I and Ill. …

Azorhizobium Caulinodans Respires With At Least Four Terminal Oxidases, Christopher Kitts, Robert A. Ludwig

Biological Sciences

In culture, Azorhizobium caulinodans used at least four terminal oxidases, cytochrome aa₃ (cytaa₃), cytd, cyto, and a second a-type cytochrome, which together mediated general, respiratory electron (e^-) transport to O₂. To genetically dissect physiological roles for these various terminal oxidases, corresponding Azorhizobium apocytochrome genes were cloned, and three cytaa₃ mutants, a cytd mutant, and a cytaa₃, cytd double mutant were constructed by reverse genetics. These cytochrome oxidase mutants were tested for growth, oxidase activities, and N₂ fixation properties both …

Multiple Modes Of Asexual Reproduction By Tropical And Subtropical Sea Star Larvae: An Unusual Adaptation For Genet Dispersal And Survival, William Jaeckle

Scholarship

Sea star larvae (Echinodermata: Asteroidea), collected from the subtropical Northwest Atlantic Ocean, exhibited three distinct modes of asexual reproduction. A number of different bipinnariae and brachiolariae reproduced by paratomous cloning of the posterolateral arms. This morphogenesis was identical to that of larvae assignable to the genus Luidia. A second mode of asexual reproduction involves the autotomization of an anterior portion of the preoral lobe. Primary larvae with preoral lobes of varying sizes and free-swimming preoral lobes of various stages of morphological development were simultaneously collected. The free-swimming preoral lobes developed complete digestive systems and ultimately assumed the form of …

The Composition And Social-Organization Of Mixed-Species Flocks In A Tropical Deciduous Forest In Western Mexico, Richard L. Hutto

Biological Sciences Faculty Publications

I recorded the flocking propensity of birds within a tropical deciduous forest in western Mexico during the nonbreeding season, and determined the species composition of 57 mixed-species, canopy insectivore flocks. Each of 27 canopy insectivore species present on the study area was observed foraging in mixed-species flocks on at least half of the occasions that it was detected on bird surveys. The proportion of flocks within which a given species was detected could be predicted on the basis of its index of abundance, as determined from independently derived point count data. Therefore, flocks are not comprised of a special subset …

Image-Eels: A Synthesis Of Energy-Loss Analysis And Imaging, Karl-Heinz Körtje

Scanning Microscopy

Two different modes of energy-filtering transmission electron microscopy (EFTEM) are often used for element microanalysis: electron energy-loss spectroscopy (EELS) and electron spectroscopic imaging (ESI).

A new approach was developed which we call Image-EELS. This procedure was realized with the commercially available standard equipment of the energy-filtering transmission microscope CEM 902 (Zeiss, Germany).

A series of energy-filtered images is recorded with ESI at many different energy losses. In a second step the intensity of selected objects is measured for each energy loss and plotted as a function of the energy loss, that means as an EELS spectrum.

This method increases the …