UNT Libraries - 7 Matching Results

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Effect of Light and Other Environmental Factors on Growth and Carotenogenesis of Corynebacterium Species Strain 7E1C

Description: This investigation studies effects of environmental factors on growth and carotenogenesis in Corynebacterium strain 7ElC. Changes in pH were found to effect growth more than carotenogenesis. However, certain nutrients or long incubation periods stimulated carotenoid formation more than growth. Dark conditions in a mineral salts-glucose medium stimulated growth, but minimized carotenogenesis. Tryptic soy broth or yeast extract elicited carotenogenesis in darkness. Although brief light exposure d… more
Date: August 1974
Creator: Howard, Marta E.
Item Type: Refine your search to only Thesis or Dissertation
open access

The Effect of Sodium Salicylate on the Ultrastructure of Trypanosoma lewisi

Description: This study examines ultrastructural changes occurring in seven- and fourteen-day populations of Trypanosorfa lewisi when 60 mg sodium salicylate is administered to the host. These changes were related to the host-immune response. Seven-day trypanosomes showed approximately 10 posterior volutin granules. Seven-day trypanosomes whose host had received salicylate exhibited. 30 to 40 volutin granules, and their posterior tip exhibited volutin granules in high numbers sometimes excluding other cellu… more
Date: August 1974
Creator: Beck, Charles F.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effects of Nutrient Media on Growth and Morphology of Azotobacter Vinelandii

Description: The work described in this thesis was undertaken to study the reasons why Azotobacter vinelandii ATCC 12837 after incubation in Burk's nitrogen-free liquid will not form as many colonies when plated on Difco Tryptic Soy Agar as when planted on Burk's nitrogen-free agar. The difference in growth of A. vinelandii on the two agars was established by performing viable cell-plate counts. The difference in growth was most apparent at 24-hours incubation of the Burk's liquid-media cultures. Phase cont… more
Date: August 1974
Creator: Butsch, Robert W.
Item Type: Refine your search to only Thesis or Dissertation
open access

The Life History and Ecology of the Mayfly Neochoroterpes mexicanus Allen (Ephemeroptera: Leptophebiidae)

Description: The life history and ecology of Neochoroterpes mexicanus was studied from data collected September, 1971, to August, 1972, and January to December, 1973, in the Brazos River, Texas. Nymphal development, instar analysis, voltinism, standing crops, and production estimates were determined from the quantitative samples taken in 1971 and 1972. Aspects of the life history and food habits of 230 specimens were arrived at from qualitative samples and light box captures in 1973. Laboratory investigatio… more
Date: August 1974
Creator: McClure, Richard G.
Item Type: Refine your search to only Thesis or Dissertation
open access

Population Studies of Ulmus Crassifolia in Flood-Plain Forests of Denton County, Texas

Description: The problem with which this investigation was concerned was the comparison of cedar elm populations in different stands along creeks in Denton County, Texas, and the relationship of certain population parameters to various substrates present at stand sites, Parameters investigated eluded average basal area, basal-area density, transect-segment density, intertree distance, lateral distance, frequency, diameter breast-high, diameter breast-high size-class distribution, and immature-tree density. … more
Date: August 1974
Creator: Koch, Linda S.
Item Type: Refine your search to only Thesis or Dissertation
open access

A Floristic Study of the Woody Vegetation of the North American Cross Timbers

Description: This research represents the first systematic collection of the woody plants throughout the Cross Timbers. It provides the first keys to these plants in their vegetative condition, plant descriptions, distribution maps, and some quantitative measurements used for descriptive purposes. Descriptions of the woody plants were constructed as an aid in verification after a specimen has been identified by use of the keys. The measurements given pertain only to the woody plants as they occur in the Cro… more
Date: December 1974
Creator: Harrison, Thieron Pike
Item Type: Refine your search to only Thesis or Dissertation
open access

Induction of Aryl Hydrocarbon Hydroxylase in Ambystoma tigrinum

Description: Aryl hydrocarbon hydroxylase (AHH) was induced 15-fold in Ambystoma tigrinum by intraperitoneal injection of 3-methylcholanthrene in corn oil, or 10-fold by addition of aromatic polycyclic hydrocarbons to the aqueous environment of the neotene animal. The cytochrome P-450-associated microsomal enzyme is similar to the inducible, one-gene, autosomal-dominant system typical in the laboratory mouse and man. Differences in optimal temperature for enzyme induction and activity were noted in organ cu… more
Date: December 1974
Creator: Colvin, David P.
Item Type: Refine your search to only Thesis or Dissertation
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