The epidermis from a range of species from the genus Allium was peeled from the base, middle, and tip of the adaxial and abaxial surfaces of leaf material. Epidermal peels were water mounted after being peeled using forceps, and photographed using Nomarski microscopy. The epidermis is composed of rows of cells which run parallel to one another, and to the long axis of the leaf. Guard cells are present on both surfaces of the leaf in most species, but some species lack guard cells on either the abaxial or adaxial surface. Guard cells are sunken to varying degrees in all species surveyed. Subsidiary cells are lacking in all species surveyed. End walls of nonstomatal cells are either even or oblique. Micropapilae, striations, or trichomes are present in some species, but most species lack epidermal structures. Epidermal cells range in size from two to three times greater in length than width to greater than fifteen times longer than wide. The majority of parallel walls are either straight or diamond-shaped while others are wrinkled, wavy, or broadened. Allium is separated into three groups according to the structure of the parallel walls. Group one includes those species with typically straight parallel walls; group two those species with diamond-shaped parallel walls; and group three is comprised of those species with wavy parallel walls.

No description available.

The studies reported herein indicate that, under the conditions commonly employed for cultivating Neisseria gonorrhoeae, colonial type T1 and T2 cultures of the organism dissociate to type T3 and T4 forms, and that this occurs both among populations of the organism grown in liquid media as well as in individual, well-isolated colonies grown on solid media.

The goal of this study is to confirm Eurasia as an independent linguistic area with respect to four features of possessive morphology: locus of marking, position of pronominal possessive affixes, obligatory possessive inflection, and possessive classification. Raw data on these features was taken from the WALS database and then run through an algorithm of genealogical stratification called g-sampling, in order to minimize the bias of the sample. The resulting g-units were then categorized by type and geographical area (New World vs. Old World, Eurasia vs. the rest of the world). These counts were tested for significance using Fisher's exact test. Two features, locus of marking and possessive classification, were confirmed to be significantly different in Eurasia; the other two features were not significantly different. Possible reasons for these areal patterns-primarily structural reasons-are briefly discussed.

The rigid peptidoglycan layer of the cell wall is responsible for maintaining the structural integrity of bacteria. Antibiotics such as penicillin exert their anti-bacterial effect by inhibiting synthesis of peptodoglycan, and enzymes such as lysozyme destroy cell integrity by hydrolyzing specific bonds in the interior of this macromolecule. Defective cells can no longer withstand the high turgor pressure within the cell because they are no longer protected by a rigid wall and tend to become fragile and spherical or irregular in shape. While all bacteria are pleomorphic under certain conditions which do not normally affect other bacteria. This is exemplified by the pleomorphic growth of Azotobacter in nutrient agar or peptone-containing medium. The purpose of this investigation was to study the nature of peptone-induced pleomorphism of Azotobacter. The first phase of study dealt with the effects of poptone on the growth and morphology of A. vinelandii. Many diverse froms were observed in peptone-containing media, but it was shown that all cell types were related to the "fungoid" family of pleomorphic cells. Although Azotobacter failed to accumulate detectable levels of cell-wall precursors in response to glycine treatment, it was shown that glycine acted only on metabolically active cells. In addition, incorporation of glycine into cell wall of Azotobacter was not required for induction of pleomorphism. Methionine and aspartic acid, and to a lesser degree alanine and isoleucine, were found to competitively inhibit glycine toxicity.

<p> In the summer of 1976 a study was undertaken of the Woodville/Codroy gypsum karst plain, an area of about 4 km^2 in southwest Newfoundland. Geology of the gypsum is revised and the general geomorphology described. Sinkholes were surveyed and classifications based on several criteria are presented. Hydro-chemistry is reported in some detail from field and laboratory analyses. It is shown that the gypsum karst system evolves in much the same \'Jay as that of limestone but at a greater rate, permitting comprehensive study of morphologic evolution within post-glacial karst areas. Processes at work in the gypsum may be initially simpler than those in carbonates but complexities of rock characteristics complicate the picture. Some water measurements indicate diffuse flow conditions in the aquifer, while others suggest conduit flow; it is demonstrated that both diffuse and conduit flow systems may operate in conjunction. </p> / Thesis / Master of Arts (MA)

No description available.

No description available.

No description available.

The simultaneous effects of dietary fiber, temperature, and daylength on the gastrointestinal morphology and physiology in meadow voles (Microtus pennsylvanicus) were investigated. Voles were randomly divided (10 in each group) and placed in 15-day treatment regimes [cold (5 C) and warm (21 C), daylengths long (18L:6D) and short (6L:18D), and diets of high fiber (50% neutral detergent fiber [NDF]) and low fiber (5% NDF) content] followed by a 5-day digestibility trial to determine diet digestibility in relation to food intake. Total mass of individuals, length, wet mass and dry mass of the stomach, small intestine, caecum, large intestine, adrenal glands, liver, and kidneys was evaluated. Data was analyzed by ANOVA using the SAS system. Meadow voles increased food intake but decreased turnover time and digestive efficiency under low ambient temperature condition, short daylength, and/or high dietary fiber. Increased energy demand had a minimal effect on the gastrointestinal tissue mass but resulted in slightly increased length of all tissues except the small intestine. The increased food intake and small changes to gastrointestinal morphology during times of increased energy demands suggest that meadow voles are able to meet their energy needs primarily through increased food intake, and therefore more energetically expensive gastrointestinal changes are minimized. / Master of Science