Biology Commons^™

Methodological Aspects Of Spontaneous Crystalluria Studies In Calcium Stone Formers, C. A. Bader, A. Chevalier, C. Hennequin, P. Jungers, M. Daudon, O. Beaugendre, M. P. Hoarau

Scanning Microscopy

Despite nearly a half-century of study, the clinical value of spontaneous crystalluria (Cx) examinations in calcium stone formers (CaSF) is still uncertain. The analytical complexity of urine particle study is largely responsible for this situation. As a result, there is no consensus regarding technical methods in Cx with several techniques for urine sampling and three different instruments currently used for particle study, namely, particle counting (PC), light microscopy (LM) and petrographic microscopy (PM). In this work, we first examined urine sampling and instrument methods regarding their appropriateness for Cx studies. Then we performed a comparative analysis of Cx studies in …

Arrangement Of Elastic Fibres In The Integument Of Domesticated Mammals, W. Meyer, K. Neurand, R. Schwarz, T. Bartels, H. Althoff

Scanning Microscopy

The hairy skin of important domesticated mammals (12 species) was studied with scanning electron microscopy, transmission electron microscopy, laser scanning microscopy, and several light microscopical methods, to obtain more information about three-dimensional elastic fibre arrangement. It was obvious that there is a basic construction scheme of the elastic fibre meshwork as present in the upper and mid-dermis, with special regard to the size, number, and grouping of hair follicles. In the densely-haired species, in particular, a typical elastic mat with horizontal fibres is formed. In many of the sparsely-haired animals, the upper and mid-dermis show a sponge-like elastic system. In …

General Pattern And Morphological Specializations Of The Avian Cochlea, Franz Peter Fischer

Scanning Microscopy

In different bird species, there is a common pattern in the hair-cell morphology and innervation of the basilar papilla; the absolute values, however, are species-specific. In the barn-owl papilla, an extreme being case, the basal high-frequency part of the papilla is greatly expanded. In this behaviorally most important frequency range of the barn owl, the number of afferent nerve terminals to neural hair cells is extensively increased. Instead of about 2 afferent terminals as in other species, up to 20 afferents are present. In the bird species studied (chicken, starling, emu, barn owl), the area of the afferent nerve terminals …

Ultrastructural Patterns Of Cell Damage And Death Following Gamma Radiation Exposure Of Murine Erythroleukemia Cells, R. Di Pietro, E. Falcieri, L. Centurione, M. A. Centurione, G. Mazzotti, R. Rana

Scanning Microscopy

Radiation causes damage to cell surface membranes, cytoplasmic organelles, and the nuclear process of DNA synthesis and repair, and this eventually results in different modes of cell death. In this study we examined murine erythroleukemia (MEL) cells, exposed to 15 and 60 Gy of 10 MeV photonic energy, and left in culture for up to 96 hours. Electron microscopical analysis was performed on conventionally embedded samples and freeze-fracture replicas, in order to detect ultrastructural patterns of cell damage and death. Of interest was the observation of chromatin condensates, nuclear membrane associations and nuclear pore redistribution during early apoptosis. Pronounced rearrangements …

The Role Of Enzyme Activation State In Limiting Carbon Assimilation Under Variable Light Conditions, Gretchen F. Sassenrath-Cole, Robert W. Pearcy, Scott J. Steinmaus

Biological Sciences

The mechanisms regulating transient photosynthesis by soybean (Glycine max) leaves were examined by comparing photosynthetic rates and carbon reduction cycle enzyme activities under flashing (saturating 1 s lightflecks separated by low photon flux density (PFD) periods of different durations) and continuous PFD. At the same mean PFD, the mean photosynthetic rates were reduced under flashing as compared to continuous light. However, as the duration of the low PFD period lengthened, the CO₂ assimilation attributable to a lightfleck increased. This enhanced lightfleck CO₂ assimilation was accounted for by a greater postillumination CO₂ fixation occurring after the …

Disparate Rates Of Molecular Evolution In Cospeciating Hosts And Parasites, M. S. Hafner, P. D. Sudman, F. X. Villablanca, T. A. Spradling, J. W. Demastes, S. A. Nadler

Biological Sciences

DNA sequences for the gene encoding mitochondrial cytochrome oxidase I in a group of rodents (pocket gophers) and their ectoparasites (chewing lice) provide evidence for cospeciation and reveal different rates of molecular evolution in the hosts and their parasites. The overall rate of nucleotide substitution (both silent and replacement changes) is approximately three times higher in lice, and the rate of synonymous substitution (based on analysis of fourfold degenerate sites) is approximately an order of magnitude greater in lice. The difference in synonymous substitution rate between lice and gophers correlates with a difference of similar magnitude in generation times.

Analysis Of The Distribution And Molecular Heterogeneity Of The Ospd Gene Among The Lyme Disease Spirochetes: Evidence For Lateral Gene Exchange, Richard T. Marconi, D. Scott Samuels, Robert K. Landry, Claude F. Garon

Biological Sciences Faculty Publications

Analysis of the ospD gene has revealed that this gene is not universal among Lyme disease spirochete isolates. The gene was found to be carried by 90, 50, and 24% of the Borrelia garinii, B. afzelii, and B. burgdorferi isolates tested. Size variability in the ospD-encoding plasmid was also observed. Sequence analysis has demonstrated the presence of various numbers of a 17-bp repeated sequence in the upstream control (promoter) region of the gene. In addition, a region within the coding sequence where various insertions, deletions, and direct repeats occur was identified. ospD gene sequences from 31 different isolates were determined …

Glycol Methacrylate Embedding And Microwave Staining For Light Microscopy Of The Mouse Cochlea, Bharti Katbamna, Atha Ralston

Scanning Microscopy

This study examined the utility of a methacrylate-based embedding medium and microwave staining for light microscopic quantification of hair cells and spiral ganglion cells in the mouse cochlea. The most important phase of the preparation process involved slowing down the polymerization process. The tissue molecules so locked within the plastic matrix produced excellent preservation of the organ of Corti and adjacent structures including the spiral ganglion, as well as tissue ionic charges. Excitable by microwaves, these ionic charges accelerated the movement of the basic dye (hematoxylin) into the tissue, reducing the time for this segment of the staining process from …

Changes In Immunoglobulin Levels In Zinc-Deficient Mice Infected With Trypanosoma Musculi, Patricia Humphrey, Clarence Lee, Mohammad Ashraf

Department of Biology Faculty Publications

A metabolic imbalance technique was used to study the effects of zinc deficiency on immunoglobulin levels in mice infected with Trypanosoma musculi or immunized with parasite products. Zinc-deficient mice developed higher numbers of parasitemia earlier and exhibited prolonged infection. Irrespective of the diet, higher IgG1, IgG2b, and IgM levels, lower IgG2a and IgA levels, and uniform IgG3 levels were exhibited primarily by mice infected with T musculi and to a lesser extent by mice immunized with parasite products. Zinc-deficient mice showed smaller increases in IgG1 and IgM, but larger gains in IgG2b compared with mice on full-complement and pair-fed diets. …

The Effect Of Insulin Mimetics On Enzymes Of Fatty Acid Biosynthesis, Eric A. Berg

Masters Theses

Fatty acid biosynthesis, an insulin regulated pathway, is the process of producing fatty acid chains from 2 and 3 carbon units. Two enzymes in this pathway that insulin affects are glucose-6-phosphate dehydrogenase (G6PDH) and fatty acid synthase (FAS). Sodium vanadate and sodium selenate have demonstrated insulin-like effects in several tissue and cell types. These mimetic effects include increasing glucose transport, regulating glycolytic enzymes, normalizing plasma glucose levels and activities of insulin regulated enzymes in diabetic rats. Our goal was to examine effects of sodium vanadate and sodium selenate on fatty acid biosynthesis in two insulin responsive systems: Isolated rat hepatocytes …

Expression Of Integrated And Methylated Hiv-Ltr In Human T-Cells And Monkey Kidney Cells By Frog Virus 3 Infection, Celene M. Spangler

Masters Theses

DNA methylation has been implicated in the suppression of transcription of a large spectrum of eukaryotic genes. Frog virus 3 (FV3) contains genomic DNA that is the most extensively methylated of all known animal viruses. However, FV3 gene expression is tightly regulated in a sequential fashion in infected cells. Therefore, FV3 must have evolved mechanism(s) to overcome the inhibitory effects of DNA methylation. FV3 has been shown to induce expression of methylated foreign genes in transient transfections. This study was designed to establish if this FV3 induced expression of methylated genes could be demonstrated in stable cell lines which contain …

Effects Of Furosemide And Oleic Acid On Thyroxine Binding To Isolated Pairs Of Thyroxine Binding Serum Proteins, Deborah Hustead

Loma Linda University Electronic Theses, Dissertations & Projects

Dosage dependent binding inhibition and redistribution of thyroxine (T₄) between three pairs of thyroxine binding serum proteins, TBG-TTR, TBG-albumin and TTR-albumin, by furosemide (0.0 to 1.0 mol/L) and oleic acid (0.0 to 0.10 mol/L) were studied using equilibrium dialysis with purified binding proteins at concentrations 1/200 of levels in normal human sera, separated across the dialysis membrane and competing for T₄.

Furosemide (1.0 mol/L) reduced TBG bound T₄ in both the TBG-TTR system and TBG-albumin system (>90% decrease) and inhibited T₄ binding to TTR in the TTR-albumin system (68% decrease) and to albumin …

The Toxicity Of Cadmium To The Aquatic Amphibian, Xenopus Laevis, Sharon S. Millirons

Master's Theses

Cadmium toxicity is poorly understood but is a potentially serious environmental pollutant. This study was initiated to determine the effect of significant concentrations of cadmium on a readily available aquatic laboratory organism.

The lethal concentration (LC50) for 50 percent of I week old Xenopus laevis tadpoles was determined to be 0.1 ppm CdCI 2. For 5 week old animals, the average LC50 was determined to be 0.98 ppm. Thus, cadmium poses greater toxic threats to the early developmental stages. Moreover, these concentrations of cadmium exceed those commonly found in the nation's water supply. Histological examination suggested that the main site …

Plumage Variation, Plasma Steroids And Social Dominance In Male House Finches, James R. Belthoff, Alfred M. Dufty Jr., Sidney A. Gauthreaux Jr.

Biology Faculty Publications and Presentations

In male House Finches (Carpodacusm exicanus), the extent and color of plumage varies depending on access to carotenoid pigments. "Colorful" males exhibit extensive red pigmentation, while less colorful (i.e., "drab") males exhibit carotenoid pigmentation over a smaller percentage of their plumage, pigmentation of a color besides red (e.g., yellow, gold, orange, or pink), or both. One explanation for maintenance of plumage variation is that it reliably reflects social status, allowing males to correctly assess their status in relation to others and avoid or minimize costly fights. Social relationships may also be related to endogenous factors, such as circulating levels of …

Time-Resolved Cryofixation Methods For The Study Of Dynamic Cellular Events By Electron Microscopy: A Review, Keith P. Ryan, Gerd Knoll

Scanning Microscopy

The preservation of cells for electron microscopy by chemical fixation is a lengthy process, requiring up to 30 minutes for cytoplasmic stabilisation. This time lag enables many changes to occur in specimens so that they may not reflect their living state when they are observed in electron microscopes. Many artefacts can be avoided by using cryofixation, which freezes specimens over a period that is measured in milliseconds, so that specimens are preserved by cryoimmobilisation. This time resolution can be used to study rapid processes in biology and chemistry because, although electron microscopes cannot observe dynamic cellular events directly, processes can …

Imaging Of Local Thermal And Electrical Conductivity With Scanning Force Microscopy, M. Maywald, R. J. Pylkki, L. J. Balk

Scanning Microscopy

The evaluation of thermal and electrical properties has been demonstrated using a scanning force microscope under ambient air condition. For the first time, the investigation of thermal conductivity on a chemical vapor deposited (CVD) grown diamond surface has been performed with a lateral resolution below 200 nm. Depending on the growing parameters, structures consisting of lines of different thicknesses and spacings are visible. The determination of the electrical structure has been carried out with a resolution of 2 nm using the contact current mode (CCM) showing similar structures. The thermal images exhibit a high thermal conductivity mostly on the diamond …

Relationship Between Ftsz Gene Expression And Chromosome Replication In Escherichia Coli, Ping Zhou, Charles E. Helmstetter

Biomedical Engineering and Sciences Faculty Publications

Transcriptional levels within the ftsQAZ region of the Escherichia coli chromosome were correlated with chromosome replication and the division cycle. The transcripts were measured either in synchronous cultures generated by the baby machine technique or in dnaC2(Ts) mutants that had been aligned for initiation of chromosome replication by temperature shifts. Transcription within the ftsZ reading frame was found to fluctuate during the cell cycle, with maximal levels about midcycle and a minimum level at division, in cells growing with a doubling time of 24 min at 37°C. Examination of transcription in dnaC(Ts) mutants aligned for chromosome replication indicated that the …

Epicuticular Wax Load Of Near-Isogenic Barley Lines Differing In Glaucousness, A. Febrero, J. L. Araus

Scanning Microscopy

Scanning electron microscopy observations of epicuticular waxes on flag leaves (blades and sheaths) and ears were carried out on a pair of near-isogenic lines of two-row barley (Hordeum vulgare L. ), derived from cv. Troubadour, differing in their degree of glaucousness (wax bloom). Plants were grown under irrigated and rainfed mediterranean conditions. Wax bloom in flag leaves consisted mainly of thin wax deposits over the blade, and tubes over the sheath. Wax bloom in the blade was denser and more uniformly arranged on the adaxial than on the abaxial side. In the ears, tubular waxes predominated, forming dense patches …

Microvascular Corrosion Casting Of The Rat Mandibular Joint: A Technical Approach, Etienne Piette, Alois Lametschwandtner

Scanning Microscopy

The rat mandibular joint is a ginglymoarthrodial joint deeply hidden under the zygomatic process of the squamosal bone. This joint was studied by scanning electron microscopy (SEM) of microvascular corrosion casts in 47 adult rats. Six additional rats were injected with India ink and thick sections of the joint area were examined by light microscopy. The small size of the joint (2.5 mm x 1.5 mm in occlusion), the existence of two slit-like joint compartments, the close proximity of bones and soft tissues in a mobile structure, and the intimate relationships of the joint with adjacent skeletal muscles made the …

Detection Of Topographic Contrast In The Scanning Electron Microscope At Low And Medium Resolution By Different Detectors And Detector Systems, J. Hejna

Scanning Microscopy

Origins of topographic contrast in the scanning electron microscope (SEM) are different at different resolution levels. At low resolution, tilt contrast of large features dominates; at medium resolution, diffusion contrast of features smaller than an interaction volume of primary electrons dominates.

The secondary electron (SE) signal, commonly used in the SEM, does not give a good tilt contrast; better contrast can be obtained with backscattered electron (BSE) signal of a converter and a sector-shaped ring detector. For obtaining topographic images from signals containing topographic and material contrast, signals of detector systems containing two or more detectors are mixed. Detector systems …

Electron Microprobe Analysis Of Electrolytes In Whole Cultured Epithelial Cells, S. Borgmann, M. Granitzer, J. Crabbé, F. X. Beck, W. Nagel, A. Dörge

Scanning Microscopy

Microprobe analysis was used to determine electrolyte contents in whole epithelial sheets of A6 cells and to investigate the most critical points of this method. Analysis of dextran standard sections of different thickness revealed that low accelerating voltages of about 10 kV are best suited for whole freeze-dried cells on thick supports, since 5 μm thick sections are not penetrated by 10 kV electrons. Washing of A6 cells for 10 sec with distilled water led to cell swelling of about 40%, but the molar concentration ratios and the concentrations per dry weight (dw) were not altered. Washing for 60 sec …

Ultrastructural Features Of Apoptosis, Elisabetta Falcieri, Pietro Gobbi, Loris Zamai, Marco Vitale

Scanning Microscopy

Apoptosis is a gene-directed physiological and programmed process of cell deletion aimed at the regulation of tissue and organ development. It affects different cell types and is triggered by a variety of stimuli all inducing closely comparable structural changes. Despite the deeply different morphology and metabolism of the cell models and the various inducers and their initial effects, a convergence seems to take place in a common metabolic pathway that, in most cases, involves the activation of a Ca²⁺ dependent endonuclease. A growing body of data is now available on the molecular events that lead to DNA damage. DNA …

Radiation Induced Membrane Changes And Programmed Cell Death: Possible Interrelationships, F. Ojeda, H. A. Diehl, H. Folch

Scanning Microscopy

A short review of the evidence that lymphocyte membranes are a target for the initiation of irradiation induced programmed cell death (PCD) is given. It is assumed that for lymphocytes PCD represents an essential physiological mechanism in order to prevent degeneration of the biological system involved. Initiation of PCD can be obtained by a pharmacological activation as well as with irradiation. In both cases, protein kinase-C (PKC) is involved in the signal transduction from the cellular membrane to the nucleus where, by means of a metabolically active process, DNA fragmentation is induced. It is hypothesized that processes connected to lipid …

Stereometry Of Crystalline Phases Observed In Scanning Electron Microscopy, M. A. Martínez, J. M. Gómez De Salazar, A. J. Criado

Scanning Microscopy

A study of edges and angles of known samples has been performed by means of stereoscopic pairs with electron microscopy in two and three dimensional systems. The derived equations have been included in a computer program. Measurements on stereoscopic pairs with different tilt angles using several crystals of galena, calcite and other objects with known dimensions have been performed. The optimum tilt angles have been obtained by comparison with the actual values, and a logarithmic ratio between these angles and the stereoscopic pairs magnification has been found. The errors obtained using this system of calculation are lower than 6% in …

Scanning Electron Microscopy And Energy-Dispersive X-Ray Microanalysis Studies Of Several Human Calculi Containing Calcium Phosphate Crystals, Tetsuo Kodaka, Kazuhiro Debari, Tsuneyoshi Sano, Masayuki Yamada

Scanning Microscopy

Human calcium phosphate calculi: two sialoliths, a urolith, a rhinolith, and a tonsillolith were investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The sialoliths and urolith had appositional shells with thick cortices, respectively, around several nuclei composed of calcospherulites and a rubber-film fragment. The rhinolith had a thin cortex with appositional laminations around a glomerulus-like mass of calcified cotton-like strings. The tonsillolith had a rough cortex with appositional laminations. Its porous interior was composed of numerous calcified conglomerates with microorganisms and calcified masses with fine appositional laminations around the conglomerates. The major crystals were identified as biological …

The Dna Sequence Required For The Maximal Transactivation Of The Vp5 Gene Of Herpes Simplex Virus Type 1, Shin Chen

Dissertations and Theses

A regulatory element involved in the transcriptional activation of the major capsid protein (VP5) of herpes simplex virus type 1 was identified and characterized in this research project. Gel mobility shift assay with nuclear extracts from both uninfected and HSV-1 infected HeLa cells identified two major protein-DNA complexes involving the VP5 promoter. No viral specific complex found. DNase I and orthophenanthroline-Cu⁺ footprint analyses in the same laboratory revealed that the two complexes involve a single binding site, GGCCATCTTGAA, located between -64 and -75 bp relative to the VP5 cap site. To determine the function of this leaky-late binding site …

An X-Ray Microanalytical Study On The Effects Of Ouabain And N-Ethyl Maleimide On The Elemental Concentrations In Malpighian Tubule Cells Of Locusta, Natalia Pivovarova, John H. Anstee, Ken Bowler

Scanning Microscopy

X-ray microanalysis was used to study elemental distribution in Malpighian tubule cells of Locusta migratoria and how these are affected by the replacement of bathing medium K⁺ with Rb⁺ and by inclusion of the transport inhibitors ouabain and n-ethyl maleimide (NEM) in standard (K⁺-containing) and Rb⁺-Ringer (K⁺-free) solutions. Incubation of tubules in standard Ringer containing 1 mM ouabain dramatically affected the intracellular levels of K and Na. The intracellular K concentration fell and Na concentration increased in all regions studied. Despite this, a gradient of increasing K concentration from basal to apical …

The Mayfly Newsletter, Peter M. Grant

The Mayfly Newsletter

The Mayfly Newsletter is the official newsletter of the Permanent Committee of the International Conferences on Ephemeroptera.

Intrapopulation Variation In Hatching Synchrony In House Wrens: Test Of The Individual-Optimization Hypothesis, Given Harper, Steven Juliano, Charles Thompson

Scholarship

Intrapopulation variation in hatching synchrony has been documented in several avian species, although little attention has been paid to this phenomenon. We experimentally reversed some synchronously and asynchronously hatched broods to test an individual-optimization hypothesis to explain variation in hatching synchrony in a population of House Wrens (Troglodytes aedon) in central Illinois. Contrary to expectation, the number and quality (as measured by mass) of fledglings produced in reversed broods was the same as that for unmanipulated broods, as were recapture rates of juveniles and offspring recruitment to subsequent breeding populations. Thus, the results do not support the individual-optimization hypothesis as …

Breeding Patterns Of Eastern Phoebes In Kansas: Adaptive Strategies Or Physiological Constraint?, Michael T. Murphy

Biology Faculty Publications and Presentations

Data were collected on annual (1980-1983) and seasonal (spring vs. summer) variation in reproduction by the double-brooded Eastern Phoebe (Sayornis phoebe) to test the proposal that phoebes modify reproductive patterns on a seasonal basis and switch from being brood survivalists in spring to brood reductionists in summer. Clutch size did not differ between spring and summer broods nor among years, but spring nests fledged one more nestling than summer nests. In 1981 breeding began earlier, eggs were larger, and nestlings grew faster than in all other years. Clutch size and egg mass within spring clutches increased seasonally. Egg mass was …