Life Sciences Commons^™

Post-Glacial Vegetational History Of The Great Bog, Belgrade, Maine, John Dawson

Senior Scholar Papers

A 6-m vibracore taken from the Great Bog in Belgrade, Maine, was sampled for pollen analysis at 10-cm intervals. Samples were processed in the laboratory using standard techniques developed by Faegri and Iversen. The sediment in the sample was reduced to a residue of pollen which was mounted on microscope slides. A minimum of 300 pollen grains was identified and counted at each level using a compound microscope at 400x magnification. Five radiocarbon dates were taken from the core at stratigraphic boundaries. Lastly, pollen concentration and pollen accumulation rates were calculated. The uppermost 3.8 m of the core is fine …

Use Of Microprojectile Bombardment In Transient Expression Assays To Analyze Protochlorophyllide Reductase Gene Expression In Greening Maize Seedling Leaf Cells, Jennifer J. Marden

Senior Scholar Papers

In young cells of leaf meristems the progenitors of chloroplasts are small organelles known as proplastids, which divide and differentiate into chloroplasts. However, in the absence of light, proplastids undergo a different sequence of development and become etioplasts. When light is supplied to etiolated plants during the "greening" process, etioplasts differentiate into chloroplasts containing chlorophyll. An important light dependent step in chlorophyll biosynthesis is the photoreduction of protochlorophyllide to chlorophyllide by the NADPH:protochlorophyllide reductase (PCR) enzyme. This enzyme is present at high activity only in etiolated tissue and during early stages of light-induced chlorophyll synthesis. The enzyme and its corresponding …

The Physiological, Enzymatic, And Genetic Characterization Of Staphylococcus Sp. Chromium (Vi) Reductase Function, Matthew J. Trudeau

Senior Scholar Papers

A strain of Staphylococcus isolated by Dr. Fekete at the Sandia National Laboratory toxic metal dumping site in Sandia, New Mexico. has been found to reduce toxic Cr(VI) to the less toxic Cr(IlI) state. We have ascertained the environmental parameters for optimal bacterial growth and Cr(VI) reduction. This knowledge may be employed in a comprehensive bioremediation scheme designed to accelerate natural reparation of that Sandia ecosystem. In addition we have investigated the genetic and enzymatic basis for this Cr(VI) reducing ability. This information may allow us to create more effective bioremediation schemes based on the comprehensive knowledge of enzyme and …

Molecular Genetic Analysis Of The Interaction Between The Bacterial Pathogen Xanthomonas Campestris Pv. Vesicatoria And The Tomato Plant, Peter M. Antall

Senior Scholar Papers

X. campestris pv. vesieatoria (Xcv) Is a bacterial pathogen of tomato and pepper. Xcv is able to infect most tomato lines. causing bacterial spot disease. which can lead to death. A strain of Xcv exists. however. which elicits a resistance response In a particular tomato line. ThIs avirulent strain carries a single locus. the aviru1ence gene avrRxv, whIch specifies the resistance inducing activity. Accordlng to Flor's gene for gene model, a corresponding gene must exist in the resistant plant. Evidence exists for this gene but it has not yet been cloned. In this study, the role ofthe avrRxv gene product …

Symbolic Interactionist And Neurophysiological Models Of Action Towards An Integration, David Spencer Fearon

Senior Scholar Papers

This research proposal introduces an integrated study of action and human conduct from the perspectives of symbolic interaction and neurophysiology. Because of their traditionally disparate subject matter, the fields of sociological social psychology and the neurosciences seldom meet; however, I have found significant common ground to justify an integrated approach to the study of action. Symbolic interactionists study human group life and conduct in society. The neurosciences deal with the physiology of the central nervous system, its structure and functions in behavior, its chemical composition, and electrochemical activity, and the effects damage has on behavior. Both fields analyze the same …

Optical Management Of The Spruce-Fir Forest Against The Spruce Budworm, Gari B. Simon

Senior Scholar Papers

Proper management of the softwood forest-budworm ecosystem is vital to the future prosperity of Maine. In choosing a management strategy, economic as well as ecological effects must be considered. This paper constructs a computer simulation model of the budworm-forest ecosystem in order to better evaluate effects of different types of forest management. The budworm-softwood forest ecosystem is a highly complicated system involving three dynamic population systems: the host tree population, the budworm population and the foliage population. Each system is modeled, by regression analysis, to observations collected by entomologists over the past half century. There are large gaps of knowledge …

Investigation Of Barbel Regeneration In The Catfish Ameiurus Nebulosus, Ruth-Marie E. Griswold

Senior Scholar Papers

It has been clearly demonstrated that the barbels of Ameiurus nebulosus regenerate completely following amputation. The current investigations involve experimentation dealing primarily with determination of the mechanisms by which regeneration occurs. However, prior to conducting a series of experiments designed to elucidate the processes which initiate regeneration, several preliminary investigations to determine normal barbel structure and regeneration were made.

Brain dissection of an adult catfish confirmed that innervation of the barbels is by both the fifth and seventh cranial nerves, and not solely by the seventh cranial nerve as suggested by Olmstead (1920). Further information regarding normal barbel innervation and …

Psychological Mechanisms In Learning Mathematical Concepts, Louis Fallon

Senior Scholar Papers

Psychological Mechanisms in learning Mathematical Concepts: Jean Piaget, the Swiss psychologist, did theoretical and experimental work based on the idea that there is an invariant heirarchy of responses by which everyone acquires mathematical concepts. Basically we tried to use the geometric symmetry concept as a vehicle for studying this process of concept acquisition using subjects ranging in age from three to 25. They were asked to reproduce a series of stimulus "pictures," simple geometric patterns, which could be used without major alteration for each age group. Symmetric responses were divided into four types which were set up into a heirarchy …

Phospholipid Inhibitor Inactivation As A Mechanism For The Activation Of Renin By Cadmium Ions, Thomas Emanuel Gallant

Senior Scholar Papers

Incubation of bovine kidney homogenates with CdCl or ZnCl2 doubles their renin activity as measured by rat bioassay. It is suggested that the activation of renin by these divalent cations results from their interference with the renin inhibitor system described by Sen et al., (1968). Failure of the inhibitor to reassociate with renin upon removal of cadmium ions by EDTA supports their renin control model. It is suggested that either renin samples prepared directly from tissue without the use of acetone powder preparations contain little phospholipase A or cadmium inactivates phospholipase A. In the absence of active phospholipase A, conversion …

Renin Granularity In The Mouse Kidney, R. Williams Soller

Senior Scholar Papers

Briefly. the rennin-angiotensin-aldosterone triangle can be thou ht of as a regulator of renal perfusion. Renin, released by the kidney in response to any threat in its perfusion n, acts on its substrate to produce angiotensin I, a mild vasoconstrictor which by means of plasma converting enzymes secretes angiotensint II. This latter product not only stimulates aldosterone output by the adrenals, but also supports the animals’ blood pressure. With aldosterone binding at the distal tubules in the kidney and this causing increased sodium retention, restoration of renal perfusion occurs – a phenomenon which shuts off the original signal for rennin …

Attempt To Determine The Pattern Of Chromosomal Inheritance In The Intermediate Iris, Theodore Kellogg

Senior Scholar Papers

Intermediate iris containing 44 chromosomes have a low rate of fertility. This paper is an attempt to determine the reasons for this low fertility through a study of the chromosomal inhertiance of two intermediate iris that have been successfully hybridized. There are no literary records showing that the results of crossing two chromosome intermediate iris, so most of this paper is a report of lab work.

Study Of Proteinuria: Isolation Of Proteins From The Nephrotic Syndrome, Merrill C. Raikes

Senior Scholar Papers

One of the most puzzling phenomena of abnormal renal physiology is the occurrence of the nephrotic syndrome. The syndrome has been defined by a collection of clinical and pathological symptoms, but there is no correlation between the clinical and pathological symptoms nor is the etiology of the syndrome known. Proteinuria is probably the most distinguishing feature in the nephrotic syndrome, and there are two possible explanations for its occurrence: (1) the excessive amounts of protein found in nephrotic urine could be due to an increased basement membrane permeability in the glomerulus of the kidney or (2) dysproteinemia. An attempt has …