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Nitrogen And Iron Interactions In Filamentous Cyanobacteria, David Allen Hutchins

Dissertations and Theses

The investigations described in this paper are an attempt to further define and quantify the interrelationship of nitrogen fixation and iron nutritional physiology in these two species. Chapter II will present and compare data on nutritional ratios of field collected Trichodesmium colonies and laboratory Anabaena cultures, with the intent of examining possible correlations between observed iron levels and protein nitrogen and chlorophyll concentrations, as well as nitrogen fixation rates. Chapter Ill is an examination of nitrogen fixation and siderophore production in Anabaena with emphasis on the possible implications of hypothesized synergistic effects of these two physiological capabilities on cyanobacterial dominance …

Fine Structure And Organ Culture Of Chick Embryo Dorsal Aorta, C. Ward Kischer, Michael Jaqua

Scanning Microscopy

Embryonic blood vessels have not been grown in organ culture, in a way which might easily submit them to studies of vascular organogenesis. The chick embryo dorsal aorta is easily accessible and relatively simple to explant to culture. Its organ culture may provide a model for wounding and repair of the intima and/or media and provide a model for studies of growth (or maintenance) and differentiation. Fresh dorsal aorta and its organ culture from the chick embryo was characterized morphologically by light microscopy scanning (SEM) and transmission electron microscopy (TEM) from days 4 to 18. Explants were incubated up to …

Effects Of Indomethacin On Prostaglandin E2 In 7,12-Dimethybenz (A) Anthracene Induced Mammary Tumorigenisis In Rats Fed Different Levels Of Polyunsaturated Fat, Candace Sue Smith

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Arts and Sciences at Morehead State University in partial fulfillment of the requirement for the Degree of Masters of Science in Biology by Candace Sue Smith on August 5, 1988.

A Reverse Genetics Approach For Studying Histone H4 Structure-Function Relationships In Yeast, Michael J. Bonaduce

Master's Theses

A previously constructed mutation of the histone H4 gene has been the subject of a detailed analysis. The mutation involves an H4 gene encoding two amino acid changes which substitute aspartic acid for glycine at positions 13 and 42 of the polypeptide. These substitutions result in a nonfunctional H4 protein when assayed in Saccharomyces cerevisiae. In contrast, an analysis of an amino terminal deletion of amino acids 3-26 results in a functional H4 protein. Physical biochemistry studies identify the sites of histone-histone interactions between residues 38-102 of histone H4, the same area in which position 42 resides. The question being …

Studies Of Intestinal Lymphoid Tissue. Xi – The Immunopathology Of Cell-Mediated Reactions In Gluten Sensitivity And Other Enteropathies, Michael N. Marsh

Scanning Microscopy

Computerised image-analysis was used to quantitate small intestinal mucosae from celiac sprue and dermatitis herpetiformis patients, Gambian children with tropical-sprue-like malabsorption, first-degree celiac sprue relatives, and treated celiac sprue patients during challenge with a peptic-tryptic digest of gluten. A wide range of mucosal appearances was observed. Typically, 'flat' lesions (Type 2) revealed a reduced number of epithelial lymphocytes that were large and mitotically active. At the other extreme, mucosal architecture was relatively well preserved (Type 1) but surface epithelium contained an expanded population of small, non-mitotic lymphocytes, with or without crypt hyperplasia. Similar changes were observed in one-third of celiac …

Chemoreceptors Regulate Discharge Of Microbasic P-Mastigophores In The Sea Anemone, Aiptasia Pallida, Gail E. Muir Giebel

Loma Linda University Electronic Theses, Dissertations & Projects

Recently, using cnida-mediated measurements of adhesive force, Thorington and Hessinger (1984, 1988a, b) identified two different chemoreceptors involved in triggering cnida discharge on the tentacles of the sea anemone, Aiptasia pallida. These two classes of receptors were shown to interact with glycine and N-acetylneuraminic acid (NANA). We now show that the discharge of the microbasic p-mastigophores, one of the three types of cnidae present on the tentacles of A. pallida, is under the controlling influence of these two classes of cnidocyte-associated chemoreceptors. We also demonstrate that the number of discharged microbasic p-mastigophores adhering to the test probes is proportional to …

Preparation Of Cultured And Isolated Cells For X-Ray Microanalysis, K. Zierold, D. Schäfer

Scanning Microscopy

Various electron microscopical preparation techniques are compared with regard to the preservation of the intracellular element distribution as determined by X-ray microanalysis in scanning and scanning transmission electron microscopy. By use of chemical agents for fixation and dehydration ions are redistributed and washed out. This is also true for freeze-substitution. Whole cells are prepared by cryofixation followed by freeze-drying. Interference of intracellular measurements by extracellular elements can be avoided by appropriate washing the cells before cryofixation. The washing medium has to be carefully selected in order to avoid distortions of the original intracellular element content. These problems are circumvented by …

Some Chemical And Physical Factors Influencing Growth Of Panus Stipticus Bulliard Ex Fries And Armillariella Mellea (Vahl Ex Fries) Karsten, James Robert Kirkland

Master's Theses

Two species of wood rotting fungi were used to investigate the possibility that growth-enhancing or inhibitory substances in woods from various trees are responsible for the distribution of these fungi in nature. Panus stipticus (Bulliard ex Fries) and Armillariella mellea (Vahl ex Fries) Karsten were cultured in the laboratory on blocks of wood from Taxodium distichum (L.) Richard, Juniperus virginiana L., Pinus taeda L. and Quercus rubra L. Panus stipticus grew well on the surface of the wood blocks; histological studies showed less penetration into the xylem of the softwoods than into that of Q. rubra. Armillariella mellea grew well …

Characterization Of Esterases And Glutathione S-Transferases In A Solitary Bee, Megachile Rotundata (Fab.): Variability, Developmental Multiplicity, Substrate Specificity, And Inhibition, Donald R. Frohlich

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The esterases and glutathione S-transferases of a solitary bee, Megachile rotundata (Fab.) (Hymenoptera: Megachilidae), the alfalfa leafcutting bee, were characterized by electrophoresis, substrate specificity, and inhibition studies. Comparisons were made between ages, sexes, and life stages for several classes of substrates and their isomers: aromatic, aliphatic, and thio-esters. Two esterases were found to be allozymes and variable between individuals and sexes. Adults typically possess an esterase that hydrolyzes fluorescent substrates, an organophosphate insensitive esterase, and a series of type 'B' esterases that are very sensitive to organophosphate inhibition. Electrophoretic patterns are different between adults and immatures and are probably …

Zinc Deficiency: Specific Scalp Hair Defects Seen By Scanning Electron Microscopy May Provide A Valuable New Test, D. W. Gregory, L. Stankler

Scanning Microscopy

Zinc deficiency in man results in multisystem disease. It may be acquired or hereditary; the latter can be fatal if left untreated. Premature babies are particularly susceptible to zinc deficiency. Unfortunately no simple, reliable test for zinc status exists at present.

Short, newly-emerging scalp hair samples from 3 classical cases of zinc deficiency all showed the same characteristic abnormalities when examined by scanning electron microscopy, i.e. straight, blunt tips bearing scales, unusually thick cuticular scales with jagged free-edges, and very fine longitudinal corrugations in individual scales. These abnormal features occurring together appear to be specific for zinc deficiency; they also …

Effects Of Ethanol And Caffeine Administered Maternally On Neonatal Adrenocortical Function, Rhonda L. Mullins Rohlfing

Biological Sciences Theses & Dissertations

Two investigations were conducted to determine the effects of maternally administered ethanol and caffeine on neonatal adrenocortical function. In the ethanol study, pregnant female rats were fed a liquid diet in which 35% of the sucrose calories were removed and replaced with ethanol. Dams in the caffeine study were injected with 25 mg/kg/day caffeine in saline solution. Within 24 hours of parturition, neonatal rats in both studies were sacrificed. The adrenal glands were incubated in vitro for one hour and media were analyzed for corticosterone content. Significant adrenal weight differences were found in both studies. The ethanol group pups were …

Scanning Electron Microscopy Of The Spermatheca Of Plethodon Larselli (Amphibia: Plethodontidae): Changes In The Surface Morphology Of The Spermathecal Tubule Prior To Ovulation, Christine M. Davitt, John H. Larsen Jr.

Scanning Microscopy

Spermathecae from eight mature female Larch Mountain salamanders (Plethodon larselli) were used to study cellular changes accompanying the administration of ovulation-inducing pregnant mare serum gonadotropin (PMSG). Animals injected daily with 25 IU of PMSG were sacrificed on day 2 or day 4. Ultrastructural alterations of the spermathecal tubules include an increase in the synthesis and release of product into the lumen and hypertrophy of two epithelial cell types by day 4. One cell type exhibits apocrine blebs and is covered with microvilli; the other contains large spherical vesicles and has only a few, short microvilli on its surface. These changes …

Microscopic Effects Of Predator Digestion On The Surfaces Of Bones And Teeth, John M. Rensberger, Hartmut B. Krentz

Scanning Microscopy

Concentrations of small fossil mammals are frequently encountered in Cenozoic deposits, but the causes for such accumulations have seldom been determined. In many cases the tooth, jaw, and limb fragments appear to be well-preserved under light microscopy, and it is difficult to differentiate damage due to predator digestion from breakage and abrasion due to physical agents. In order to find more specific evidence of predator digestion, we used a scanning electron microscope (SEM) to examine the surface microstructure of bones and teeth consumed by Bubo virginianus (great horned owl) and Canis latrans (coyote), which prey upon similar species. Effects …

Leafcutting And Diet Selection: Relative Influence Of Leaf Chemistry And Physical Features, Jerome J. Howard

Biological Sciences Faculty Publications

The effects of leaf toughness, trichome characteristics, nutrient and water availability, and secondary chemistry on diet selection by the leafcutting ant Atta cephalotes were determined using individuals of 49 woody plant species from a tropical deciduous forest in Costa Rica. The palatability of plants was measured by presenting whole leaves to leafcutting ant foragers on trails and counting the number of pieces cut from leaves. The effectiveness of physical barriers to leaf cutting was evaluated by measuring the speed with which ants were able to cut leaves of varying toughness, trichome densities, and trichome lengths. Plant secondary chemistry was highly …

The Diatom Flora Of The Red Lake Peatland, Minnesota, Thomas P. Pienkowski, Daniel E. Wujek

Journal of the Minnesota Academy of Science

Diatoms collected from three transects in the Red Lake Peatland occur in characteristic assemblages. One hundred two taxa were observed from 26 sample sites, with Eunotia exigua and Pinnularia rupestris the most dominant species. Clustering indicated three peatland types were present: rich fen, transitional and poor fen, and bog.

Cellular Politics: Ernest Everett Just, Richard B. Goldschmidt, And The Attempt To Reconcile Embryology And Genetics, Scott F. Gilbert

Biology Faculty Works

No abstract provided.

Lake Mead Prefertilization Study: Preliminary Nutrient Enhancement Studies In Lake Mead, Richard P. Axler, Larry J. Paulson, Patrick J. Sollberger, Donald H. Baepler, U.S. Bureau Of Reclamation

Publications (WR)

Studies conducted by the University of Nevada-Las Vegas (UNLV), the Nevada Department of Wildlife (NDOW), the Arizona Game and Fish Department (AGFD), The Nevada Division of Environmental Protection (NDEP), and the United States Bureau of Reclamation (USBR) have identified decreased algal production as a major factor involved in the decline of the Lake Mead sport fishery. Phosphorus-laden silt particles in the Colorado River have been sedimenting out in Lake Powell since the completion of Glen Canyon Dam 286 miles upstream in 1963. This sharp decrease in phosphorus loading to Lake Mead (>5000 tons per year) has resulted in decreased …

Use Of Woody Vegetation By Beavers In Southeastern Virginia, John L. Echternach, Robert K. Rose

Biological Sciences Faculty Publications

Nonbreeding and sometimes transient beavers, Castor canadensis, cut a variety of woody plants throughout the year during a 15-month study at three sites in southeastern Virginia. Ten species of trees were cut in proportions greater than would be expected according to their availabilities. Beavers heavily used viburnum, alder, ironwood, bayberry, tulip poplar, and dogwood. Winter food caches were constructed but were only lightly used.

Scanning Electron Microscopy Of Oral Mucosa In Vivo And In Vitro: A Review, Kristina Arvidson, Roland C. Grafström, Anders Pemer

Scanning Microscopy

The oral mucosa is classified by function into lining, masticatory and specialized oral mucosa, with regional structural adaptation. In this review, the surface structures of the human oral mucosa have been studied in the scanning electron microscope (SEM). Regional variations in regard to keratinization, cell arrangements and microplications with related specific structures observed in SEM are described and correlated with the appearance of similar areas observed in the light microscope. Furthermore, human oral tissue and cell cultures have also been studied. These systems offer usable and complementary models for performing similar studies in vitro under controlled experimental conditions. We now …

Storage Of Sperm In The Reptilian Oviduct, Daniel H. Gist, Jeffrey M. Jones

Scanning Microscopy

Female reptiles have the ability to store sperm within their reproductive tracts for extended periods of time. Sites of sperm storage in lizards and snakes include both the anterior vagina and the infundibulum. Vaginal receptacles are found in between longitudinal folds (snakes) and in tubules formed by invaginations of the epithelium (lizards). Infundibular receptacles are alveolar or tubular in structure and are formed from invaginations into the lamina propria of the oviduct wall. In turtles, sperm are stored in the posterior portion of the tuba, in tubular albumen-secreting glands. Sperm may be embedded within the cells of the receptacles, but …

The Vascularization Of The Vertebral Column Of Rats, M. A. Konerding, M. Blank

Scanning Microscopy

The intrinsic and extrinsic blood supplies of the vertebral column of rats have been examined by corrosion cast with Mercox CL2B(R). The close functional and topographic relationship of vessels to supplied structures were exposed by fractionated maceration of the soft tissues. The segmental arteries diverge into an anterior, median and posterior group with various anastomoses between their branches. Vertebral bodies and intervertebral discs are preferably supplied by branches of the anterior and median section. The vessels reaching the vertebral body from the dorsal side diverge in a treelike branching mode into the direction of the vertebral endplate. The venous drainage …

Tooth Enamel Structure In The Koala, Phascolarctos Cinereus: - Some Functional Interpretations, William G. Young, Maria Mcgowan, Terrence J. Daley

Scanning Microscopy

The purpose of this study is to determine whether the structural organization of Pattern 2 marsupial enamel in the Koala is disposed to resist wear on the sectorial crests of the molar teeth. The orientation of wear on the crests is uniformly delineated by parallel scratches on their polished surfaces. Twin blades, a leading and a trailing edge of enamel are formed on each crest by wear into dentine on which the differential wear at enamel to dentine interfaces indicates that the direction of wear is labial to lingual.

96 leading and trailing edges from 12 koala molars were examined …

The Isolation And Identification Of Filamentous Fungi From Distribution Systems, Ground Water, Cisterns And Hemodialysis Water, Tammy J. Liles

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Arts and Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Tammy J. Liles on August 18, 1987.

Estimation Of Food Limitation In Daphnia Pulex From Boulder Basin, Lake Mead, Thomas Mark Bartanen

Publications (WR)

In February, 1982 I began a year-long study to determine if growth and reproduction in Daphnia Pulex were limited by the amount of food available in Boulder Basin, Lake Mead. To determine this, I made monthly collections of Daphnia Pulex and natural lake seston from an already established station in Boulder Basin. I cultured the Daphnia Pulex under simulated field conditions in a flow-through feeding apparatus using four different food regimes; 1-natural lake seston filtered through 80 um mesh to remove other zooplankton, 2-lake seston (as above) with an enrichment of 10³ cells-ml^-1 of Chlamydomonas reinhardti, 3-lake …

Scanning Electron Microscopy Of Black Stain On Human Permanent Teeth, J. Theilade, K. M. Pang

Scanning Microscopy

Black stain may develop on the coronal surfaces of human teeth, and this type of stain is common in the Hong Kong Chinese population. The present study was undertaken to ascertain if the deposit conforms in composition to the black stain found elsewhere, and to describe its ultrastructure using the scanning electron microscope. Gram-stained smears were made from black stain on the teeth of 11 adult Hong Kong Chinese and studied microscopically. From another 15 persons extracted teeth exhibiting black stain were obtained and fixed. Two ground sections were made from each tooth, one was stained with toluidine blue, the …

Effects Of Fractionated Irradiation On The Esophageal Mucosa: A Scanning And Transmission Electron Microscopic Study, M. Albertsson, C-H Hakansson, C. Mercke, H. Morner

Scanning Microscopy

The mucosa of rabbit esophagus was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy. Specimens were taken for scanning electron microscopy, transmission electron microscopy and light microscopy investigations. Examination was made 1-10 days after each fractionation schedule. Light microscopy showed dose-dependent edema of the irradiated mucosa which also could be seen and scored from SEM pictures. SEM investigations showed that this was accompanied by loosening of microridges and a slightly increased cell loss. By SEM, a varying amount of bacteria could be seen which did not make intimate contact with the surface cells.

During …

The Effect Of Cellulolytic Rumen Bacteria Or Their Cell-Free Extracts On The Germination Of Euonymus Americanus L., Gary Thomas Howard

Masters Theses & Specialist Projects

In past attempts, the experimental germination of the seeds of Euonymus americanus L. in vitro has had little success. However, treatment of seeds with rumen fluid containing viable microflora has been successful in stimulating germination. In the presence of the cellulolytic rumen bacterium. Clostridium cellobioparum ATCC 15832, seeds of E. americanus were stimulated to germinate. Subsequent studies were designed to determine whether the bacterium synthesized a cellulolytic enzyme responsible for initiating germination. The cell-free endocellulase from C. cellobioparum was demonstrated to induce germination of the seeds. To support the hypothesis that endocellulase from C. cellobioparum was responsible for triggering germination, …

The Fine Structure Of The Human Placental Villus As Revealed By Scanning Electron Microscopy, G. J. Burton

Scanning Microscopy

Scanning electron microscopy of the placenta has a history of only twenty years. During that time, however, there have been dramatic advances in instrument technology coupled with the refinement of preparative techniques designed to reduce fixation artifacts to a minimum. As a result many of the early claims must be amended or suitably qualified, and this is one aim of the present review.

Much new data on the internal structure of the placental villus is also presented. By means of the partial digestion technique it is now possible to describe the three dimensional configuration of the various components of the …

Leafcutting Ant Diet Selection: The Role Of Nutrients, Water, And Secondary Chemistry, Jerome J. Howard

Biological Sciences Faculty Publications

The relationship of plant secondary chemistry, water content, and nutrient content to the palatability of leaves to the leafcutting ant Atta cephalotes was determined in a study of individuals from 50 woody plant species in tropical dry forest of Costa Rica. The study took place during the yearly period of maximum leaf harvest, in the early rainy season. The palatability of plants was determined by presenting leaf disks to ants on active foraging trails of three ant colonies. The distribution of several classes of polar secondary compounds in leaf samples was determined using chemical spot tests, and that of ant- …

Fatigue From High- And Low-Frequency Muscle Stimulation: Contractile And Biochemical Alterations, Joseph Mark Metzger, Robert H. Fitts

Biological Sciences Faculty Research and Publications

This study examined the effect of high- (75 Hz, 1 min) and low- (5 Hz, 1.5 min) frequency stimulation on contractile and biochemical properties of the diaphragm. Tension was reduced to 21 ± 1 and 54 ± 2% (SE) of the initial value after high- and low-frequency stimulation, respectively. After 0, 0.25, 1, and 2 min of recovery from high-frequency stimulation, 5 Hz elicited more force (expressed as % of initial tension) than 75-Hz stimulation. Time 0 recovery values were 21 ± 1 and 78 ± 6% of the initial force for 75- and 5-Hz stimulation, respectively. By 1 min …