Life Sciences Commons^™

The Neonatal Chinchilla Cochlea: Morphological And Functional Study, R. V. Harrison, J. R. Cullen, S. Takeno, R. J. Mount

Scanning Microscopy

The developmental time scale of the cochlea varies from species to species. We investigate here the condition of the neonatal cochlea in the chinchilla, a species increasingly used in auditory research. We have examined the morphology of cochlear hair cells using scanning microscopy, and the development of auditory function during the first postnatal month by monitoring auditory brainstem evoked responses (ABR). We find that although there were some outer hair cell kinocilia present in middle and apical areas, the hair cells otherwise were mature at 24 hours after birth. Furthermore, cochlear auditory thresholds are adult-like at birth. However, whilst there …

The Influence Of Fluorescent Light On The Development Of In Vitro Fertilized Bovine Oocytes, Jared Bunch

Undergraduate Honors Capstone Projects

Advances in in vitro fertilization and in vitro culture techniques have allowed considerable progress in identifying physiological requirements of mammalian embryos. Parrish et al. (11) reported a major breakthrough on in vitro fertilization when his group identified heparin as an important factor for the capacitation of spermatozoa. Capacitation is necessary for fertilization of matured oocytes. During the precoculture era of embryos (prior to 1980), the development of early preirnplantation embryos was vary limited regardless of medium, medium supplement, gas atmosphere, osmolarity or pH used (7). Coculture techniques of fertilized oocytes using somatic cells during in vitro production, particularly of bovine …

The Effect Of Thyroid Hormone On The Expression Of A7 Myosin Heavy Chain Mrna In Xenopus Laevis, Bradley Thomas Butkovich

Master's Theses

It has long been known that thyroid hormone (TH) is responsible for metamorphosis in tadpoles. It is also known that A7 MHC, an adult muscle isoform, is expressed in adult Xenopus laevis frogs, but not in larvae. Furthermore, the appearance of A7 corresponds with the onset of metamorphosis. The present study investigated the relationship between TH and the expression of A7 MHC mRNA in Xenopus laevis. Isolated tails in culture and 6-n-propyl 2-thiouracil (PTU) treated tails were treated with TH and the presence of A7 mRNA analyzed with in-situ hybridization, and RT-PCR. It was found that TH caused substantial …

Landscape Scale Habitat Conservation Plans: The California Experience, Lindell L. Marsh

Biodiversity Protection: Implementation and Reform of the Endangered Species Act (Summer Conference, June 9-12)

24 pages.

Contains 3 pages of references.

Impact Of The Human Genome Project At The Interface Between Patent And Fda Laws, Brian C. Cunningham

RISK: Health, Safety & Environment (1990-2002)

Mr. Cunningham stresses the broad scope of biotechnological innovations. Besides endorsing the need for a new oversight commission to deal with potential social issues, he suggests, for example, that some products should be treated like biologics rather than new drugs.

Touch-Plate And Statolith Formation In Graviceptors Of Ephyrae Which Developed While Weightless In Space, Dorothy B. Spangenberg, Elisa Coccaro, Russell Schwarte, Brian Lowe

Scanning Microscopy

Ultrastructural studies of the statocysts and touch-plates of graviceptors (rhopalia) of Aurelia ephyrae revealed that (1) touch-plate hair cells are present; and (2) cytoplasmic strands from the hair cell bases extend from the neurite plexus to touch similar strands from the lithocytes. This close association of hair cell neurites and statocysts may have important implications regarding the transmitting and processing of positional information with respect to the gravity vector.

Graviceptors of ephyrae which developed while weightless in microgravity were compared with controls at the ultrastructural level. We found that hair cells of ephyrae which developed in microgravity had fewer lipid …

Development Of An Ovine Genome Map With Emphasis On In Situ Hybridization, Melanie R. Heaton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Livestock genome maps are used to identify economic trait loci and loci proximal to genes affecting economically important traits. This research contributes to the development of the ovine genome map by establishing techniques to physically map large DNA inserts to ovine chromosomes using fluorescent in situ hybridization. Fluorescent in situ hybridization techniques were established using yeast artificial chromosomes as DNA probes. Probes were as large as 1,000,000 kilobases and hybridized to fixed ovine metaphase chromosomes from a callipyge ewe. Three yeast artificial chromosome probes contained a genetic marker for the ovine callipyge gene. Probes were assigned to ovine chromosome pair …

Development Of An Enzyme Linked Immunosorbent Assay Capable Of Detecting Antibodies Specific To The Cytomegalovirus, Rachel Bird

Undergraduate Honors Capstone Projects

The cytomegalovirus (CMV) is capable of causing serious illness and death in immunocompromised individuals. The objective of this research is to develop a method of detecting antibodies against CMV. This has lead to the development of an Enzyme linked Immunosorbent Assay (ELISA) that is capable of detecting CMV or anti-CMV antibodies. The process in the development of such an assay involves; 1) the purification of Hyperimmune Rabbit Serum containing anti-CMV antibodies, 2) determination of the appropriate concentrations necessary to provide a clear and concise response to the test, and 3) testing of monoclonal antibodies to determine their specificity towards the …

Genetic Dissection Of The Morphological Evolution Of Maize, John Doebley

Aliso: A Journal of Systematic and Floristic Botany

Maize (Zea mays ssp. mays) and its wild progenitor, teosinte (Z. mays ssp. parviglumis) differ dramatically in inflorescence and plant architecture despite the fact that their evolutionary divergence occurred within the past 10,000 years or less. To elucidate the genetic control of the morphological differences between maize and teosinte, my colleague and I employed quantitative trait locus mapping with molecular markers. Results indicated that most of the variation in plant and inflorescence morphology between maize and teosinte can be explained by five restricted regions of the genome. In this paper, characterization of three of these regions …

The Effects Of Thyroid Hormone On Myosin Heavy Chain A-7 Production In Xenopus Laevis Tail And Leg Muscles, Andrew R. Noble

Honors Theses

The present research examines the expression of myosin heavy chain genes in muscle fibers in Xenopus laevis. Characteristically different muscle fibers are expressed before and after metamorphosis. The embryonic myosin proteins that are synthesized during the tadpole stages are replaced with adult myosin heavy chains at metamorphosis. At least one of the adult myosin genes, called A-7, is expressed only in the adult animals, not in tadpoles. The controlling factor or trigger for the expression of this adult gene still remains unknown. There are a number of possible explanations for the A-7 regulation at metamorphosis, including changes in particular hormone …

Does The Monocot Mode Of Leaf Development Characterize All Monocots?, Geeta Bharathan

Aliso: A Journal of Systematic and Floristic Botany

Patterns of early leaf development in monocots are analyzed in a phylogenetic context. Recent developmental and phylogenetic studies enable this reevaluation of the leaf base model of the developing monocot leaf. Two questions are addressed: a) is the presence of the Vorläuferspitze (fore-runner tip) invariably correlated with development of the lamina from the lower leaf zone? and b) was the ancestral monocot characterized by the leaf base mode of development? Scanning electron microscopic observations are made of young primorida using the mold and cast method. These data are combined with data from the literature and examined in a phylogenetic context …

Integrating Cellular And Molecular Approchaes Into Studies Of Development And Evolution: The Issue Of Morphological Homology, Andrés Collazo, Scott E. Fraser

Aliso: A Journal of Systematic and Floristic Botany

Understanding the development and evolution of complex morphological characters requires broad, multidisciplinary approaches. By combining biological imaging, phylogenetic analyses, embryological manipulations and additional modem molecular techniques (e.g., whole mount in situ hybridization), we can address fundamental questions, such as the determination of homology. Many of the novel structures that evolved in vertebrates and distinguish them from their ancestors (such as jaws and the mechanosensory lateral line) are derived embryonically from two migratory ectodermal tissues, neural crest and/or various epidermal placodes. In particular, time-lapse cinematography of fluorescently labeled cells in living Xenopus and fish embryos has proved a powerful technique, revealing …