Starch gel electrophoresis was used to compare 14 proteins encoded by 15 loci for seven species of the family Icteridae. A close genetic relationship among these species was classified into three groups. The Agelaiine group contained Agelaius phoeniceus, Sturnella magna, and S. neglecta. The Quiscaline group contained Euphagus cyanocephalus, Cassidix mexicanus, and Quiscalus quiscula. Molothrus ater, the most divergent, was placed in a separate group. Divergence times for the seven species were compared to the literature. Heterozygosity of the seven populations of the two species of Sturnella were compared to determine factors influencing their divergence. Two factors proposed were heterosis in S. neglecta and possible hybridization between S. neglect and S. magna.
The purpose of this study was to extend our understanding of the ecological relationships of P. aeruginosa by investigating the differences or similarities between the strains of this organism found in sewage and those found as pathogens in human infections. This research was approached by comparing the serological types of P. aeruginosa isolated from sewage contaminated waters in Argentina (South America) to those isolated from sewage contaminated waters in Texas. They were typed with sera obtained using P. aeruginosa isolated from human infections. The data obtained revealed that bacteria isolated from sewage in Texas and from soil and water in Argentina are antigenically similar to those isolated from human infections.
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 during inoculation was photoinductive, continuous exposure to light following inoculation was required for maximum pigment synthesis. Dark grown stationary phase cells required 24-hours of light for maximum pigment synthesis. Chloramphenicol inhibition of carotenogenesis in dark grown cells exposed to light showed that enzymes needed for carotenoid synthesis were absent from dark grown cultures.
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 cellular elements. Fourteen-day trypanosones showed fewer volutin granules than seven-day, salicylate-treated ones. Salicylate treatment caused no additional ultrastructural alterations. Thus the volutin granules are not linked to the reproduction inhibiting antibody (ablast in) but may be involved in the formation of the trypanocidal antibodies.
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 contrast microscopic observations of Tryptic Soy media cultures of A. vinelandii disclosed the regular formation of fungoid cells at early stages of growth of the bacteria, 18 to 24 hours.
Laboratory studies conducted at 5, 15, 25, and 35 C measured changes in gilling rates and oxygen consumption of green sunfish in response to exposure to bentonite clay suspensions. The tests indicate that gilling rates are not affected by bentonite clay suspensions below 2125 FTU at 5 C, 1012 FTU at 15 C, and 898 FTU at 25 C. At turbidity levels exceeding 1012 FTU at 15 C and 898 at 25 C, gilling rates increased 50-70%. Tests were inconclusive at 35 C. Oxygen consumption rates were found to be unaffected by turbid suspensions below 3500 FTU at all four temperatures. Evidence suggests that increased gilling rates under highly turbid conditions are a means of compensating for reduced respiratory efficiency and a strategy for maintaining a constant oxygen uptake. Evidence indicates that the cost of increased gilling rates is probably met by a reduction in activity.
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 culture of human and Ambystoma tissues, and ratios of benzpyrene metabolites differed between Ambystoma and Mus. The half life of enzyme activity induced in vivo was related to the excretion of hydrocarbon metabolites.
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 investigation in 1973 helped in establishing instar analysis, egg incubation and description, and first instar descriptions. Neochoroterpes mexicanus appeared to have three generations per year with brood overlap in the summer and fall. It displayed 16 and 19 instars for overwintering and combined summer generations respectively.
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. Variations among populations of Ulmus crassifolia Nutt were noted and analyzed in terms of soil particle size and existing community conditions.
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