UNT Libraries - Browse

Individual, Social, and Seasonal Behavior of the Thirteen-Lined Ground Squirrel (Spermophilus tridecemlineatus)
The purpose of this study is to provide a qualitative, detailed description of individual and social behavior in a free-living population of thirteen-lined ground squirrels. Behavioral differences in relation to various periods of the annual cycle are also evaluated.
A Comparative Study of Passive Transfer Mechanisms of Tuberculin and Chemical Contact Delayed Hypersensitivities in the Guiea Pig
This study is concerned with a critical comparison of the passive transfer mechanisms of tuberculin and chemical contact hypersensitivities in the guinea pig by use of a four phase experimental approach.
A Characterization of Liver Glyoxalase I From Normal Mice and Mice Bearing Lymphosarcoma
The purpose of this investigation was (1) to isolate and purify glyoxalase I from the livers of normal DBA/lJ mice and the livers from mice bearing a lymphosarcoma tumor; and (2) to determine, at least with respect to glyoxalase I, if the tumor has an effect on the chemical properties or structure of macromolecules in an organ removed from tumor locale and not histologically affected by its presence.
Food, Feeding Selectivity, and Ecological Efficiencies of Fundulus notatus (Rafinesque) (Osteichthyes; Cyprinodontidae)
This study was made to further define the trophic dynamics of Fundulus notatus by determining its ration composition under natural conditions, measuring feeding selectivity under various laboratory conditions of prey-species composition and availability, and determining the efficiencies with which F. notatus utilizes ingested chironomid larvae.
Mixed Culture of Chlorella Pyrenoidosa TX71105 and a Variant Strain of Bacillus Megaterium
Very little work has been done on bacteria capable of significantly inhibiting algal growth. This thesis reports the research on mixed cultures of a high-temperature strain of algae, Chlorella pyrenoidosa TX71105, and an organism isolated from the air and tentatively identified as a variant strain of Bacillus megaterium.
Experimental Trichinosis in Birds
This work concerns itself with essentially four experiments: (1) the cecum-injective-infection experiment; (2) the anus-injective-infection experiment; (3) the mouth ingestive-infection with larvae, and (4) the mouth ingestive-infection with the flesh of infected rats.
The Influence of a Return of Native Grasslands upon the Ecology and Distribution of Small Rodents in Big Bend National Park
In the southwestern United States there is a delicate balance between the existing grasslands and the rodent fauna. The purpose of this investigation was to determine the influence of secondary succession of native grasslands upon the ecology and distribution of small rodents. Two methods of determining the rodent species were plot quadrates and trap lines using Sherman live traps.
Obligately Thermophilic Nitrogen-Fixation in Some Soil Bacteria
In the work presented here, it is claimed that bacteria have been isolated which are capable of growth at high temperatures utilizing molecular nitrogen as their sole nitrogen source. Soil bacteria were isolated which grew at 55 C in nitrogen-free media. They were found to be obligatory thermophiles in nitrogen-free media and facultative thermophiles in media containing organically bound nitrogen.
A Taxonomic Study of the Family Bacteroidaceae
This study was performed to clarify the taxonomy of the bacteria in the family Bacteroidaceae.
Effects of Carbaryl (1-Naphthyl-n-methylcarbamate) on Trichocorixa Reticulata (Hemiptera: Corixidae) and Glyptotendipes Barbipes (Diptera: Chironomidae)
My study of the effects of carbaryl in aquatic systems under controlled laboratory conditions emphasized four major objectives: (1) to determine the acute toxicity of carbaryl to the herbivorous adult and immature Trichocorixa reticulata (Guerin)(Hemiptera: Corixidae), and to the omnivorous larvae of Glyptotendipes barbipes (Staeger) (Diptera: Chironomidae) under static bioassay; (2) to adapt a quantitative method of analysis for carbaryl in water and whole insect tissue extract; (3) to measure the accumulation of the insecticide by G. barbipes under static exposure; and (4) to quantify the uptake and loss of carbaryl by G. barbipes under daily-renewed sublethal dosages.
The Larval Lipids of the Chironomid Midge Glyptotendipes Barbipes (Staeger)
This problem was concerned with determining the total lipid content and individual lipid composition of the larvae of a local chironomid, Glyptotendipes barbipes (Staeger).
Some Effects of Electrostatic Fields on Brain Activity in Rats
This study concerned the effects of short-term exposures to continuous (10 kv/meter) and pulsed 20 volts at 640 cps/100 msecs) electrostatic fields on the EEG recorded from external electrodes and hypothalamic activity recorded from implanted electrodes in rats. Each experiment lasted at least 90 minutes. The total energies of the waveforms recorded were integrated and printed out for plotting and analysis. Besides the brain activity, the ECG, respiration, and temperature of the animals were also monitored before, during,and after exposure to the electrostatic fields.
Studies on the Morphology and Biology of Cotton Rats (Sigmodon hispidus) from Northern Mexico to Southern Nebraska
This investigation was designed to evaluate the need for retaining both Sigmodon hispidus texianus and Sigmodon hispidus berlandieri as subspecific designations. An attempt was made to demonstrate bioclimatic variation and reproductive seasonality in cotton rats. The validity of applying the results of isolated studies of cotton rat populations to the species as a whole was examined.
X-irradiation Effects on the Action Potentials of Frog Sciatic Nerves Inhibited by Carbon Monoxide and Ouabain
The response of frog sciatic nerve action potentials to x-irradiation and metabolic (carbon monoxide) or transport (ouabain) inhibition was determined in an attempt to further identify the nature of radiation insult to nervous tissue. Carbon monoxide, ouabain (2 X 10-5 M), and nitrogen anoxia were shown to produce a near linear decline in action potential amplitude. The carbon monoxide and nitrogen inhibitions of activity were reversible in air; the carbon monoxide inhibition was light reversible. Ouabain inhibition was partially reversible by soaking the nerve in aerated Ringer's. Application of 120 kv x-rays (75 Kr at 4.9 Kr/min) to nerves during the linear decline in spike amplitude brought about a marked enhancement (146%) of inhibition by 99% CO/l% 02, nitrogen (136%), and ouabain (265%). All bhanges were shown to be statistically significant by a regression analysis. However, x-irradiation did not appear to alter the air reversibility of carbon monoxide and nitrogen inhibitions nor the reversibility in Ringerts of the ouabain inhibition. Additionally x-irradiation completely blocked light reversal of 98% CO/2% 02 inhibition and produced a decline in activity. A possible interpretation of these results is a compensation for radiation action at this dosage requiring metabolism and ion pump activity.
Effect of Indole-3-Acetic Acid on the Nucleic Acids of Synchronous Cultures of Chlorella Pyrenoidosa
It was the purpose of this study to investigate the effect of various concentrations of IAA on the nucleic acids of Chlorella pyrenoidosa TX 7-11-05. The time during the life cycle when the greatest effect occurred was investigated by the use of synchronous cultures.
Effects of a Methylcholanthrene-Induced Lymphosarcoma on the Blood of DBA/1J Mice
This investigation was concerned with characterizing a tumor line induced and maintained in this laboratory. Various chemical assays, cell counts, and electron microscopy were the methods employed to characterize the blood of mice bearing the tumor at days 3, 6, 9, and 12 after injection of the 1.2 x 10^8 tumor cells.
Some Acute Effects of X-Irradiation (LD100) on Plasma and Adrenal Tissue Histamine in Rats
The effects of a lethal dose (1380 r) of X-irradiation on plasma and adrenal tissue histamine levels of rats were studied. The plasma histamine response was triphasic (increase at 1-3 hours, decrease at 5 and 9 hours and return to control at 24 hours post-irradiation). The adrenal tissue histamine response was found to be biphasic (decrease at 1 to 9 hours and a return to control level at 24 hours post-irradiation).
A Carcinogenic Agent Elaborated by Liver Cells from Lymphosarcoma-Bearing Mice
Liver cells from lymphosarcoma-bearing DBA/1J mice were shown, by parabiotic culture with normal liver cells from isologous mice, to elaborate an agent which could pass a 25 mu filter and transform the normal cells to a malignant state.
Lipids and Phospholipase Activity of Vibrio Cholerae
One purpose of this investigation is to determine the fatty acid and lipid content of typical Vibrio cholerae cells. The comparison of cholera lipid constituents with those of closely-related bacteria might be of taxonomic value. Furthermore, chemical characterization of the cholera vibrio could provide useful criteria for identification of these disease-producing microorganisms.
Isolation and Characterization of Malic Enzyme from Ascaris suum
A procedure for the isolation of malic enzyme from muscle tissue of the roundworm Ascaris suum is described. The fractionation method yields relatively large quantities of the enzyme,with a specific activity of fifteen moles of malate converted to pyruvate and carbon dioxide per min per mg at 25º. Homogeneity was established with analytical ultracentrifugation, zone electrophoresis, isoelectric focusing, and rechromatography. The molecular weight of the enzyme was 250,000, and it is dissociated under several conditions into four identical monomers of 64,000 daltons. The enzyme exists as a single electrophoretic form and prefers manganous and NAD over other cations and NADP. Ammonium sulfate competes with manganous for the active site and titration with DTNB yields eight thiol groups per mole. Titration of the first four thiol groups is accompanied by a complete loss in enzyme activity. Equilibrium dialysis, product inhibition, and initial velocity studies suggest a rapid-equilibrium random sequential mechanism for the Ascaris suum malic enzyme. The presence of 1.3 binding sites per subunits was determined for L-ma late. Antisera prepared against A. suum malic enzyme reacted to a small extent with the NAD malic enzymes from two free-living nematodes, Panarellus redivivus and Turbatrix aceti. A correlation coefficient of 0.911 was obtained upon comparing the amino acid composition of A. suum and E. coli malic enzymes. Some sequence homology is predicted between these malic enzymes. The physiological interpretation favors the binding of malate initially, with the subsequent addition of NAD to the enzyme.
Carbon Flux in Reservoir Sediments
The central objective of the study was to fractionate sedimenting organic materials according to their source (allochthonous or autochthonous) and ultimately to determine the degree of biodegradability of contributions from either source with particular reference to activities at the mud-water interface.
Effects of a Methylcholanthrene-Induced Lymphosarcoma on Various Tissues of DBA/1J and Swiss White Mice
This investigation was concerned with characterizing effects of this tumor line on lipid metabolism in DBA/lJ mice and serum protein levels and cellular changes in DBA/lJ and Swiss white mice. Total lipids, lipid phosphorus, neutral lipids, and changes in fatty acids were determined in liver, spleen, skin, and tumor of DBA/lJ mice bearing the lymphosarcoma at various days after injection of tumor cells.
Influence of Acclimation and Acclimatization to Seasonal Temperatures on Metabolism and Energetics in the Rusty Lizard Sceloporus Olivaceus
Rates and energy equivalents of consumption (C), egestion+ excretion (FU) , assimilation (A), respiration (R) and production (P) were measured in two groups of Sceloporus olivaceus: 1) a laboratory group acclimated at four seasonally encountered temperatures (15, 20, 25 and 30°C) ; and 2) four acclimatization groups collected at different seasons when ambient temperatures corresponded to 15, 20, 25 and 30°C.
Trophogenic Ecology of Selected Southwestern Reservoirs
Three north central Texas reservoirs (Grapevine Reservoir, Lake Ray Hubbard, Lewisville Reservoir) were investigated in order to characterize the nutritional ecology, phytoplankton community structure, and primary productivity within the trophogenic zones of each. Emphasis was placed on elucidating the relative influences of the major nutrients (C, N, P, Fe, Si) and various other physico-chemical parameters on phytoplankton community biomass, structure, and productivity. Extensive physical, chemical, and biological analyses consisting of approximately eighty parameter measurements were made on each of twenty-three integrated water samples (surface to three meters) taken from the three reservoirs during the period July, 1971 to June, 1972. New methods which were employed included a high-intensity ultraviolet photocombustion procedure for the determination of total nitrogen, phosphorus, and iron, and an in vitro oxygen method for estimating community metabolism. General chemical and physical regimes are described for the three reservoirs, and various interrelationships discussed. Phytoplankton communities are delineated on bases of species composition, volume, diversity, pigments, and metabolism data. The more salient biotic and physico-chemical interrelationships are examined within the context of the limiting nutrient controversy.
Biological Nitrogen Fixation in Two Southwestern Reservoirs
This investigation has determined the presence of biological nitrogen fixation in two reservoirs in the southwestern United States: Lake Arlington and Lake Ray Hubbard. Subsequent tests have gathered baseline data on the effects of various biological, chemical, and physical parameters on in situ nitrogen fixation in these reservoirs. Of specific importance is the relationship between nitrogen fixation arid occasional blooms of blue-green algae which produce such problems as testes and odors in these water-supply impoundments.
Effects of 2-Chloroethylphosphonic Acid (Ethephen) on Scenedesmus Quadricauda
The effects of various concentrations of 2-chloroethylphosphcnic acid (Ethephon), an ethylene-releasing compound, on the total protein, deoxyribonucleic acid (DNA), and ribonucleic acid (RNA) levels in Scenedesmus quadricauda IU 614 were investigated.
Biochemical Systematics of the Genus Sophora
Three unusual amino acids, y-amino-n-butyric acid, pipecolic acid, and 4-hydroxypipecolic acid, and an uncommon dipeptide, y-glutamyltyrosine, have been isolated and characterized from the seeds of members of the genus Sophora. Structural proof of these compounds was carried out by paper chromatography, thin-layer chromatography, column chromatography on amino acid analyzer, infrared, nuclear magnetic resonance, mass spectrometry, and C, H, N analysis. The presence and absence of these compounds was used as a criterion for the classification of 23 species of the genus Sophora. A phylogenetic classification which seems to follow the morphological taxonomy of this genus was carried out on the basis of seeds that contained pipecolic acid, those which did not contain pipecolic acid, and plants which contained both pipecolic acid and 4-hydroxypipecolic acids. Another chemical classification was also introduced based on the presence and absence of y-amino-n-butyric acid and y-glutamyltyrosine.
Evolutionary Genetics of Certain Mice of the Peromyscus boylii Species Group
The genetic structure of 49 natural populations of four species (P. attwateri, P. boylii, P. pectoralis, and P. polius) of the Peromyscus boylii species group was analyzed through application of chromosomal and electrophoretic techniques. Chromosomal variation within and among populations of the boylii species group was analyzed from 178 specimens. Electrophoretic techniques were utilized for the demonstration of variation in enzymes and other proteins encoded by structural loci and applied to the study of the evolution of the boylii species group by estimation of levels of genetic heterozygosity within populations, estimation of degree of genetic similarity between conspecific populations and between species, and determination of patterns of geographic variation in allelic frequencies and levels of heterozygosity. Six distinct chromosomal patterns were observed among the populations of the four species of the boylii species group. All specimens had a diploid number of 48 and the major difference in chromosomal morphology was in the number of pairs of large to medium biarmed autosomes. Little or no chromosomal variation was observed in three species (attwateri, pectoralis and polius), but considerable chromosomal variation occurred among populations of P. boylii. Generally, the chromosomal variation in P. bylii was between allopatric populations, with each chromosomal pattern limited to a recognized subspecies. Polymorphism was observed in two populations. The polymorphism observed in P. polius was the result of pericentric inversion involving the smallest pair of metacentric autosomes. The polymorphism observed in P. bolii cileus was interpreted at the result of gene flow between P. boylii rowleyi and P. boylii spicilegus. In addition to chromosomal evidence, analysis of electrophoretic data demonstrated and suggested effective gene flow between the chromosomal forms of P. boylii. Electrophoretically demonstrable variation was analyzed in 11 proteins encoded by 17 autosomal loci. Of the 17 structural loci, 11 were polymorphic in one or more ...
The Vertical Stratification of the Macrobenthos in the Brazos River, Texas
Quantification of stream macrobenthos populations has remained a perplexing problem in rivbrine ecology, despite numerous attempts at improvement. This is in part due to well documented variations in chemical and physical parameters locally and geographically, and resultant adapted macrobenthos populations. Southwood (1968) and Hynes (1970a) have reviewed the various sampling techniques developed'for the census of lotic macrobenthos populations. Needham and Usinger (1956), Chutter (1969), and others have pointed out the difficulty in obtaining adequate numbers of samples which will yield population estimates with desired statistical confidence, and still maintain some degree of sampling economy. Needham and Usinger (1956) and Gaufin et al. (1956) mentioned the "patchy" distribution of aquatic insect populations as the primary source of this difficulty. The concept of patchy distribution in insect populations was originally discussed by Andrewartha (1961). Attempts to improve confidence through improved sampling devices and techniques have led to development of numerous types of samplers. Cummins (1962) indicated that there were almost as many samplers as there were researchers.
The Distribution of Pathogenic Pseudomonas aeruginosa in Sewage
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.
Effects of Turbidity on Gilling Rates and Oxygen Consumption on Green Sunfish, Lepomis cyanellus
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.
Biochemical Genetics of Certain Species of the Blackbird Family Icteridae
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 Stoneflies (Plecoptera) of Texas
An illustrated key to the adults and known nymphs of Texas Plecoptera is provided. Species accounts, including geographic distribution within Texas, and biological notes are given. Of the twenty-seven species of Plecoptera known from Texas, six are new state records. TWo species new to science, Isoperla jewetti and Isoperla coushatta are described. Taeniopteryx starki Stewart and Szczytko, Zealeuctra arnoldi Ricker and Ross, and Zealeuctra hitei Ricker and Ross are endemic to the Edwards Plateau area of Texas. Two species, Mesocapnia frisoni (Baumam and Gaufin) and Isoperla jewetti New Species are western in origin. The remaining nineteen species (excluding Anacroneuria) are typically eastern species.
Evolutionary Genetics of Three Semispecies of Wood Rats--Neotoma Albigula, Neotoma Micropus, and Neotoma Floridana
Electrophoretic variation in 18 proteins encoded by 20 autosomal loci was used to compare the genetic relationships of 19 natural populations representing three species of the subgenus Neotoma. Of the 20 loci examined nine were monomorphic and fixed for the same allele in all populations. No more than seven loci were polymorphic within a single population. Genetic variability was expressed as the proportion of loci heterozygous in the average individual of a population. Heterozygosity in the three species of Neotoma studied averaged 0.078, a value within the range reported for other rodents. Although the levels of heterozygosity seen in Neotoma could not readily be explained, the variation may be attributed to ecological factors. The three species of Neotoma were compared on the basis of genetic similarity and found to form a close taxonomic unit, probably semispecies. Divergence times were obtained for the three species and found to compare well with divergence times obtained from fossil data. In general, the three species have diverged within the last 112,000 years during the Wisconsin glacial period.
Genic Differentiation and Evolution in the Ground Squirrel Subgenus Ictidomys (Spermophilus)
The genetic structure of 26 natural populations of three species (S. tridecemlineatus, S. mexicanus, and S. spilosoma) of the Ictidomys subgenus of ground squirrels was analyzed using chromosomal and electrophoretic techniques. Chromosomal variation was not observed in S. mexicanus, and only slight karyotypic variation was found in the other two species. Chromosomal evidence indicated hybridization between S. tridecemlineatus and S. mexicanus, placing these species within the classical definition of semispecies. Analysis of electrophoretic variation at 29 genetic loci indicated close genetic relationships between these species. Evolution in Ictidomys appears to be linked with Pleistocene events, and speciation appears to have occurred within the last 155,000 years.
Hematological Parameters of the Bluegill, Lepomis machrochirus (Rafinesque), Including Effects of Turbidity, Chloramines, and Flexibacter columnaris
Normal ranges of values for hematological parameters of bluegill gathered seasonally from three lakes were determined. Sexual, seasonal, and inter-lake variations were found. Effects of 2-wk exposure to turbidity on blood parameters included an increase in rbc size and a decrease in small lymphocytes. Effects of 3-hr exposure were increases in rbc count, hemoglobin, and pH and decreases in PG2 and large lymphocytes. The effects of 0.44 and 0.88 ppm chloramines were an increase in blood pH, a decrease in MEV, and severe spastic reactions resulting in loss of equilibrium or death in 90% of the fish. Effects of Flexibacter columnaris included an increase in transformed lymphocytes and a decrease in small lymphocytes.
Drumming Behavior of Selected Nearctic Stoneflies (Plecoptera)
Drumming was recorded for 11 of 13 Nearctic stonefly species, representing 4 families. Both male and female signals were obtained from 5 species, and were either 2-way or 3-way communications. Signals were species-specific; those of males and females varied from 3-39 and 1-14 beats/ signal, respectively. Duration of male signals varied from 105-8,016 ms; those of females, except Perlinella drymo (1 beat), varied from 402-1318 ms. Signals among related taxa showed greatest similarities. Duration of male signals of Perlinella drymo became progressively shorter at each of 4 temperatures from 7-29 0C. Females of Perlinella drymo would only repeatedly answer male signals recorded at near their own temperature, and would not repeatedly answer recorded male signals of 8 other species.
The Effect of Ethanol on Cardiac Activity and Brain Respiration in Chick Embryos
This study concerned the effect of ethanol on cardiac activity and brain respiration in chick embryos. Ethanol dosages tested ranged from 1.0 mg to 4.0 mg/g weight. Each experiment lasted at least 150 minutes. Cardiac activity in terms of total waveform energies was integrated and printed out for plotting and analysis. The embryonic heart rates were simultaneously determined from physical graph tracings. The embryonic brain respiration was measured using a differential microrespirometer. The effect of ethanol on cardiac activity was one of slight (10 to 13), but statistically significant (p<.05) rate depression. The brain slices exhibited a marked, immediate, and irreversible decrease (39 to 89%) in oxygen consumption at both ethanol dosages. The data indicated that chick embryonic brain tissues were more susceptible to alcohol effects than cardiac tissue. Therefore, the mental abnormalities seen in the offspring of alcoholic mothers may be more cerebral in nature than cardiovascular.
Food Habits of Stoneflies (Plecoptera) in the Gunnison and Dolores Rivers, Colorado
Gut contents of 2,500 stonefly nymphs, comprising 10 species, from the Gunnison and Dolores Rivers, Colorado were examined from Dec., 1974-Oct., 1975. Perlidae species were carnivorous feeding primarily on chironomids, mayflies and caddisflies. Seasonal patterns of ingestion and preference varied among species and predator sizes and between rivers. Early instar polyphagous species utilized detritus in the fall, eventually shifting to carnivorous habits as they grew through winter-spring. Pteronarcids fed predominantly on detritus. Dietary overlap of predators was greatest in the Gunnison River, with subtle mechanisms such as prey species and size selectivity, temporal succession and seasonal shifts to detritus-plant material in some, providing reduction of competition. A more complete partitioning of prey resources was evident in the Dolores River.
Immunocompetence in the AKR Mouse
A model for the study of the relationship of immunity to cancer is found in AKR mice which harbor Gross virus. This genetically transmitted virus is present in a latent form for months before it spontaneously induces leukemia. Many investigators have demonstrated near normal humoral responses, but abnormal cellular immunity in the preleukemic animal. With increasing age, pathology of the disease is expressed, reflecting diminished immunity. In this study, the ontogeny of humoral antibodies of AKR/J and SWR/J mice was assayed by microagglutination techniques in response to thymus-independent, thymus-dependent, and solubilized antigens. Simultaneous injections of thymusdependent and -independent antigens provided data suggesting an impaired humoral response in the AKR mouse.
Comparative Chemistry of Thermally Stressed North Lake and Its Water Source, Elm Fork Trinity River
To better understand abiotic dynamics in Southern reservoirs receiving heated effluents, water was analyzed before and after impoundment in 330 ha North Lake. Macronutrients, metals, and chlorinated hydrocarbons were measured. Concentrations of nutrients and metals in sediments were quantified in this 2 yr study. River water prior to impoundment contained 16 times more total phosphorus, and supported 23 times more Selenastrum capricornutum cells in an algal assay than reservoir water. The reservoir has essentially no drainage and since evaporation is high, the concentrations of many dissolved solids have increased since the reservoir was filled in 1958. North Lake is now phosphorus limited. Apparently altered chemical equilibria have caused precipitation or adsorption of phosphorus with calcium and iron.
DNA-DNA Hybridization of Methane Oxidizing Bacteria
Bacteria classified in the family Methylomonadaceae must derive their carbon from one-carbon compounds. They are characterized by the possession of internal membranes of two types. Type I membranes are layered and fill the middle of the cells while type II membranes form concentric layers around the periphery of the cells. Also, there are two metabolic pathways by which the methylobacteria assimilate one-carbon compounds. Further evidence of this dichotomy was sought by DNA-DNA saturation hybridization of DNAs from both types of methylobacteria. Very low DNA-DNA homology was seen between types I and II or within the types. It was not possible, therefore, to correlate the degree of genetic relatedness with either the nature of the internal membranes or the pathway of carbon assimilation.
Serological Relationships of Azotobacter Species
In order to clarify the taxonomic problems which exist among the group azotobacter by serological method, 24 cultures of Azotobacter including 9 species were tested as antigens in Ouchterlony plates against 3 different antisera obtained from rabbits immunized with A. chroococcum ACl6, A. macrocytogenes St.M. and A. vinelandii 12837, respectively. The results showed more cross reactivity in intraspecies reactions than in interspecies ones and indicated the presence of a common immunogenic determinant. This work presents the results which suggest the effecient classification of Azotobacter by Ouchterlony comparisons of corresponding antigens in different species.
Effect of Amino Acids on Growth and Cartenogenesis in Corynebacterium Species Strain 7E1C
Studies were evaluated on the effects of known growth factors on the growth and carotenogenesis of Corynebacterium species strain 7ElC. The complex medium, Tryptic Soy Broth,was found to stimulate growth and production of more pigment in the light and in the dark than did a mineral salts-glucose medium. A complete amino acid mixture added to LSG enhanced carotenogenesis in the dark in Corynebacterium 7ElC, while B-vitamins retarded carotenogenesis. No absolute requirement for one or more amino acids was found,indicating a multiple amino acid requirement. The fewest amino acids found to stimulate carotenogenesis in the dark were a combination of those in the Serine and Histidine families which include serine, glycine, cysteine, and histidine.
A Study of the Water-Soluble Antigens from Virulent and Attenuated Biotypes of Brucella abortus
Through chemical analysis and ion exchange chromatography of watersoluble antigens, this investigation supports the view that the majority of differences between the biotypes are quantitative. It was also found that strains demonstrate distinct, qualitative differences when compared to the attenuated strain 19 by immunodiffusion and thin-layer polyacrylamide gel, isoelectric focusing. These differences include the presence of antigens on virulent strains that are absent on strain 19. In addition, one antigen absent on strain 19, was found common to each virulent biotype. Finally, the results from immunodiffusion experiments, employing adsorbed and non-adsorbed immune globulins, indicate that at least some water-soluble antigens are exposed on the cell surface and that their distribution among the biotypes varies.
The Relation Between Carbon Assimilation and Biomass Dynamics in a Phytoplankton Community
Production dynamics in the phytoplankton community of a mesotrophic Texas reservoir were measured weekly over a four month period using 14C incubation and ATP assay methodologies. Assimilation values of 14C ranged from 0.2 to 45 ug C 1 hr1 - . Significant positive and occasionally negative changes in biomass (i.e. viable organic carbon) were observed in short term (4 hr) in situ incubations juxtapo-sitioned with the 14C experiments; viable organic carbon production, estimated with the ATP assay, ranged from -25 to +50 ug C 1l1hr1. Carbon assimilation and biomass changes did not correlate in either short term (4-5 hr.) or over the study period (6 months). However, weekly biomass trends were predicted by relative positive or negative biomass changes in the short term incubations. Biomass measurements gave a more sensitive insight into production dynamics in the phytoplankton community than did carbon assimilation measurements.
An Assay Method for Determining Extra-Cellular Lipases from Pseudomonas aeruginosa
The applicability of an isotopically labelled assay system to determine the lipase production in Pseudomonas aeruginosa was evaluated. Supernatant from cultures of Pseudomonas aeruginosa grown in a medium containing olive oil was incubated with a substrate containing labelled trioleate. Fatty acids were isolated by means of a liquid-liquid partition system. Enzyme activity was determined by measuring the amounts of free fatty acid by liquid scintillation counting. Findings indicate that the isotopicallylabelled, liquid-liquid partitioning assay is reliable, sensitive and adaptable to rapid assay conditions. It was also determined that different strains of Pseudomonas aeruginosa produce varying amounts of lipase. Partial purification of supernatant by gel filtration produced two protein peaks showing enzymatic activity.
Nymphs of the Stonefly (Plecoptera) Genus Taeniopteryx of North America
Nymphs of the 9 Nearctic Taeniopteryx species were reared and studied, 1976-78. Two morphologically allied groupings, the Taeniopteryx burksi-maura, and T. litalonicera- starki complexes corresponded with adult complexes. A key separating 7 species, based primarily upon pigment patterns and abdominal setal arrangements, was constructed. Taeniopteryx lita and T. starki were indistinguishable; T. burksi was separated from T. maurawhen no developing femoral spur was present. This study was based upon 839 nymphs. Mouthparts were not species-diagnostic. Detailed habitus illustrations were made for 6 species. Egg SEM study revealed that 3 species were 1.2-1.4 mm diameter, with a highly sculptured chorion, generally resembling a Maclura fruit; micropyle were scattered. Taeniopteryx lita, lonicera, starki and ugola nymphs were described for the first time.
Production and Energy Metabolism in Three Benthic Insect Populations in a Small North Central Texas Pond
Annual energy budgets of dominant benthic macro-invertebrates were examined during November 1973 to October 1974 from the benthos of a small pond ecosystem in north-central Texas. Estimates of annual secondary production (Hynes and Coleman 1968) were Procladius s. (Diptera, Chironimidae), 2.4 g m^-2 y^-1 (13 kcal m^-2 y^-1 ); Tendipes decorus (Diptera, Chironomidae), 6.0 g m^-2 y^-1 (40 kcal m^-2 y^-1 ); Brachycercus sp. (Ephemeroptera, Caenidae), 1.9 g m^-2 y^-1 (11 kcal m^-2 y^-1). Energy metabolism was measured in the laboratory at six seasonally encountered temperatures (5, 10, 15, 20, 25, and 30 C) on an acclimatization basis, and then extrapolated to the field. Estimates of annual energy metabolism are Procladius sp., 5.0 kcal m^-2 y^-1 ; Tendipes decorus, 17.2 kcal m^-2 y^-1 ; Brachycercus sp. 40.0 kcal m^-2 y^-1.
Thermal Selection at an Enzyme Locus in Populations of the Red Shiner, Notropis lutrensis, Receiving Hypolimnion Effluents from a Reservoir
Genetic variation was examined at 19 loci encoding enzymatic and general proteins Notropis lutrensis from the Brazos River in Texas. The thermal regime of the Brazos River below Possum Kingdom Reservoir is altered due to the release of water from the hypolimnion. Summer water temperatures fluctuate as much as 7^oC. Levels of heterozygosity at the malate dehydrogenase-2 locus were correlated with the degree of water temperature fluctuation at each locality. The isozymes from three homozygous patterns of supernatant malate dehydrogenase (Mdh-l, Mdh-2) exhibited different activities at different experimental temperatures.