Developmental Biology Commons^™

Características De La Osificación Craneal En Phyllomedusa Boliviana (Anura: Hylidae), Rafael O. De Sá, E. O. Lavilla

Biology Faculty Publications

RESUMEN. Dentro de la familia Hylidae disponemos de información sobre las secuencias de osificación craneal para menos del 4.0% de sus miembros. El presente trabajo describe la secuencia de osificación craneal de Phyllomedusa boliviana. El patrón general de osificación es similar a lo reportado para otras especies de la familia, pero existen algunas diferencias importantes tales como la osificación tardía de los próoticos y la osificación premetamórfica de neopalatino, vómer, cuadrado-yugal, pterigoides y columela. El lento desarrollo ulterior de la osificación resulta en juveniles con cráneos extensamente cartilaginosos.

ABSTRACT. Characteristics of the cranial ossification in Phyllomedusa …

Geographic And Nongeographic Variation In The Genus Microtus (Mammalia: Rodentia) In West Virginia, Tina M. Savage

Theses, Dissertations and Capstones

Geographic and nongeographic variation was assessed on 12 cranial and 4 external characters in approximately 400 specimens of Microtus (M. ochrogaster, M. chrotorrhinus, M. pinetorum, M. pennsylvanicus) in West Virginia. Univariate and multivariate statistical analyses were used to examine age-related variation, sexual dimorphism, elevation and geographic variation and litter size for each species of Microtus in the state. Cranial characters were more beneficial than external in detecting variation. Examination of data for each species of Microtus studied demonstrated that values and trends in variation is a specific rather than a generic trait. Age-related variation was present in some, …

Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá

Biology Faculty Publications

Model organisms are often assumed to be representative of some more inclusive taxon of which the species is a part. This assumption leads to mistaken generalizations about the evolutionary and comparative significance of the data gathered. This paper reviews com? parative and evolutionary studies of Xenopus laevis and its relatives. Phylogenetic analysis of data from DNA sequences and morphology indicate that Xenopus is monophyletic and that Silurana is its sister group. The most basal lineages of Pipidae diverged prior to the breakup of Gondwana. The bizarre morphology of Xenopus is in part due to changes in the mode of meta? …

Fertilization And Mouse Embryo Development In The Presence Of Midazolam, Maria Leavitt

Biological Sciences Theses & Dissertations

The development of mouse embryos in vitro has provided a unique opportunity for the study of cellular differentiation and the influence of various agents on differentiation. Midazolam is administered for conscious sedation in the recovery of human ova. In the Norfolk IVF Program, midazolam is found in varying concentrations in follicular fluid. Mouse embryo formation and development has been used to test midazolam's effect on fertilization and early development as a model of human in vitro fertilization and development. Midazolam' s effects were studied using varying doses of midazolam on (1) in vivo fertilization and subsequent cell division, and (2) …

Microsurgical Fertilization Of Mammalian Eggs: An Assessment Of Clinical Utilization, Susan E. Lanzendorf

Theses and Dissertations in Biomedical Sciences

Microsurgical fertilization is the technique in which a spermatozoon or sperm nucleus is injected into the cytoplasm of an egg. To establish a foundation for the use of microsurgical fertilization as a means of treating infertility, this study evaluated the procedure in hamster and human eggs. Hamster sperm nuclei were microinjected into hamster eggs to determine the rate of abnormal fertilization and to ultrastructurally assess cellular damage by transmission electron microscopy. Hamster eggs were also injected with human spermatozoa obtained from fertile and infertile men to evaluate the fertilizing potential of the sperm cells. In addition, human eggs donated by …

Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Macroscopically, the testes of Chthonerpeton indistinctum consist of a series of oval lobes. The number and size of lobes is variable in Chthonerpeton indistinctum. Histologically, the testes are divided into structural units, locules separated by septa of connective tissue. Inside of each locule spermatogenesis takes place in cysts of germinal cells that divide synchronically. Chthonerpeton indistinctum is divided chronologically into four stages of development based on the shape of the nuclei of the spermatids and their arrangement in the cyst: (1) round, (2) kidney shaped, (3) attenuate, and (4) bouquet arrangement.

The Ductuli Efferentes In Macaca Mulatta: Electron Microscopic Evaluation Of Changes After Vasectomy, Loyal Douglas Marsh

Dissertations and Theses

After vasectomy, the passage of sperm antigen through the epithelium of the efferent duct in the rhesus macaque probably results in immune complex deposition. Immune complexes can be visualized in the thickened basement by fluorescence microscopy. Subsequent electron microscopic evaluation, with the appearance of electron-dense deposits in the basement membrane of the efferent ducts, substantiates these findings.

Storage And Use Of Glycogen By Juvenile Carcinonemertes Errans, D. Mitchell Wolgamott

Dissertations and Theses

Juvenile C. errans do not feed on particulate matter and yet they can survive, apparently unchanged, for several months before maturing into the adult stage which feeds on the eggs of Cancer magister. The significance of glycogen as an energy source for maintenance of the juvenile form was investigated.

The Development Of The Sporangium Of Aspidium (Cyrtomium) Falcatum, Rita Thorpe

Bachelors’ Theses

It is the purpose of the writer in this thesis, to describe the development of the sporangium of Aspidium (Cyrtomium) falcatum, and to observe some of the cytological features of the sporogenous cells.

The Effect Of Potassium-Iodide On The Embryological Development Of The Chick With Special Reference To The Growth Of The Long Bones., David M. Polot 1904-1978

Electronic Theses and Dissertations

No abstract provided.

Spermatogenesis Of The Butterfly, Papilio Rutulus, John P. Munson

All Faculty Scholarship for the College of the Sciences

For a number of years I have been studying the spermatogenesis of Papilio rutulus (pl. 12, fig. 1) not ,with any one single problem especially in view, but with the aim of ascertaining the entire life history of its sperm cell, its various phases of development, its mode of growth and differentiation, the history of its several parts, and its relation to the organism.