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.

A large, multi-basin, reservoir (Garza-Little Elm Reservoir) in north central Texas was studied to determine the relative effects of various parameters on primary productivity. The basins were impounded several years apart,thus allowing the influence of age on water chemistry and biota to be considered. Another principal influence on water quality was secondary sewage effluent that entered one basin from a nearby source.

This investigation was concerned with three aspects of the problem of passive dispersal of algae and protozoa by aquatic insects: the role of odonates in passive dispersal of viable small aquatic organisms, the passage of viable algae and protozoa through digestive tracts of field-collected herbivorous and carnivorous aquatic insects, and the viability duration of selected algae, during insect transport under monitored conditions.

The literature on the effects of phytohormone on algae is clouded with contradictory reports. Reports have been published which substantiate and deny the effects of phytohormones in enhancing the growth and developmental processes in algae. The overall aim of this study was to investigate the response, if any, of the phytohormones indole-3-acetic acid (IAA), gibberellic acid A3 (GA) and kinetin on the physiology of the green alga, Scenedesmus quadricauda. Results obtained for the uptake of 14^C-IAA an(j l4C-kinetin by Scenedesmus strongly support the presumption that the alga does not absorb the hormones. The retention of the phytohormones by the alga is due to adsorption, and is independent of hormone concentration. Most of the label was adsorbed by the outer pectic layers of the cell wall.

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.

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 …

Electrophoretic techniques were utilized for the demonstration of variation in 22 proteins from 24 natural populations of four species ( G. bursarius, G. pinetis, G. arenarius and G. personatus ) of the Geomys complex of pocket gophers. Of the 24 structural loci , 19 were considered to be polymorphic. Five of the six esterases contributed greatested to the polymorphism while non-esterase proteins generally showed low values. In the GeoMys complex of pocket gophers in this study,selection appeared to be the most important influence on genetic structure with some evidence of random drift in two of the four species. Populations of G. arenarius and G. personatus had the highest average interspecific genetic similarities to G. bursarius and . pinetis was the most divergent. Biochemical evidence supports the phylogeny of Geomys based on morphological and fossil data.

A unique undosciribed gramnegative rod is extensively characterized in this study. The cells of this unusual water isolate measure 1.2 X 6.5 microns, The most distinguishing characteristic of the bacterium is a polar tuft of 35-40 flagella that aggregate to function as a single organelle which is visible under phase contrast. Aging cells deposit poly- -hydroxybutyric acid granules which are bound by an inclusion membrane made up of four distinct layers. It also possesses an unusual exterior membrane outside the cell wall which contains large fibrils of protein running at a slight angle to the longitudinal axis of the cell. The guanosine-cytosine ratio was found to be 62.2$. The organism's taxonomic position was further investigated by immunological, morphological, and biochemical methods. It was found to be most closely akin to members of the genus Pseudo onas, although somewhat divergent from other species classified in this genus. After careful evaluation of the findings obtained during this study, the new bacterium was subsequently named Pseudomonas multiflagella.

The systematic relationship of two species of the Peromyscus truei group (P. truei and P. difficilis) was analysed through the application of starch gel electrophoresis, numerical taxonomy, and chromosomal techiques. Of 20 loci examined, 11 were monomorphic in all populations, two exhibited variation in only two populations, and seven loci were polymorphic in two or more populations. The mean number of polymorphic loci per population was 0.186, the mean number of polymorphic loci per individual was 0.024, and the proportion of loci heterozygous per individual was 2.4%. Chromosomal forms of P. truei, P. t. gentilis (FN 54) and P. t. truei (FN 62), and P. difficilis, P. d. petricola (FN 56) and P. d. nasutus (FN 58), were consistent for their karyotypes throughout their geographic ranges. No chromosomal hybrids were detected. Numerical analysis of morphological characters and similarity values based on allelic frequencies utilizing Roger's coefficient (S) demonstrated a distinct seperation of karyotypic forms of P. truei (S = 0.902) and P. difficilis (S = 0.924) and were below the mean value of S for conspecifics (S = 0.950). All data indicates that each chromosomal form of the P. truei group examined represents four distinct species. The oldest available name …

Accurate identification is fundamental in any study of grasses by farmers, ranchers, range specialists, ecologists, or students interested in the changes taking place in the grass habitat. Frequently it is convenient, and sometimes it is necessary, to identify the grasses by their vegetative characters. Some are readily recognized at a glance by their habitat and certain characters well known to the experienced observer. In other cases, identification is more difficult; and, perhaps with a few, it is impossible to be certain of the species from vegetative characters. However, this may also be true when the characters of the floral parts alone are considered. The inflorescence, used in most keys and descriptions, is often available only for a short period of time. Identification by the characters of the vegetation can be used throughout the growing season, even if grazing or mowing has removed or prevented the development of the floral parts. There have been other studies of grass identification related to vegetative characters, but they have been local and have not covered North Central Texas. This paper provides a means of identifying grasses by their vegetative characters. It can be used by the scientist, the technician, and the layman interested in …

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.

This research investigates interacting biological, chemical, and physical factors affecting the efficiency of microbiological wastewater treatment at the W. J. Smith Wood- Preserving Company in Denison, Texas. The treatment process consisted of collecting exhaust boiler water containing unidentified boiler treatment compounds, steam condensate contaminated with preservatives and wood extracts, plant process waters, and rainfall runoff from plant grounds. With a 5-minute residence time, wastewater was passed over 2 oxidation towers in series, each containing approximately 47,000 square feet of surface area. Suspended solids were removed from the wastewater before discharge. Various amino acids such as serine, aspartate, cysteine, phenylalanine, alanine, proline, glycine, histidine, and tyrosine significantly stimulated phenol degradation in the laboratory. The plant wastewater contained approximately 0.1 mg/l of several of the stimulatory amino acids. It was assumed that these concentrations provided maximal stimulation in the field situation. The plant wastewater also contained sufficient nitrogen to permit the organisms to degrade up to 100 mg phenol/1 of water examined. Amino acids in the wastewater probably serve as a source of microbial nutrition. Toxicity of the wastewater to fish was not caused by the presence of phenol, phenol degradation products, or traces of pentachlorophenol. The wastewater was rendered non-toxic by …

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 …

The development and refinement of FA has been adequately investigated with major emphasis on pathogenic microorganisms. The development of this technique has reduced both the time and number of biochemical tests necessary to identify a diversity of organisms. The organisms included are the protozoans, as described by Goldman (1953 and 1957) and by Ingram (1961), viruses, as reported by Liu (1955a) and Burgdorfer and Lackman (1960a), pathogenic bacteria which have been investigated by Moody, Goldman, and Thomason (1956), Moody and Winter (1959), Deason, Falcone, and Harris (1957) and Thomason, Cherry, and Moody (1957). Various fungi have been studied with FA by Kaufman and Brandt (1964), Kaufman and Kaplan (1961 and 1963) and Gordon (1958). Therefore, due to the success of the fluorescent antibody technique in many areas of microbiology in previous investigations, the logical assumption was that immunofluorescence might be incorporated into an efficient system in which a specific organism associated with fecal pollution, such as S. faecalis, could be rapidly identified. Based on this assumption, the feasibility of fluorescent antibody techniques, using S. faecalis was investigated as a means of rapid determination of bacterial pollution in water. Although much progress has been achieved in the study of cytochemical reactions …

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 …

The linkage relationship and arm location of the gene for greenbug resistance in the variety Will was determined by using primary trisonomics and tertiary trisomic homozygous translocations. The gene for greenbug resistance was found to be on linkage group 1 by using primary trisonomics. The gene was located on the cetromere segment of the Tl-6a translocation by using a tertiary trismoic homozygous for greenbug resistance. The data further substantiates the feasibility of using trisomics in placing genes on proper linkage groups.

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.

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.

It was the purpose of this investigation to attempt to demonstrate if differences in eutrophic levels existed among selected areas of Garza-Little Elm, and to demonstrate the role that sediments play in affecting eutrophication.

The purpose of this study was as follows: 1. Elucidate the laboratory conditions under which Anabaena circinalis produces the noxious odor component or components in maximum concentration, 2. Isolate the major noxious odorous metabolite(s), 3. Structurally define the odorous metabolite(s), 4. Quantitate the amount of metabolite(s) that a given amount of the organism produced.

This study was performed to clarify the taxonomy of the bacteria in the family Bacteroidaceae.

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.

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.

Investigations concerning the cellular response of tumor tissue to treatment with dimethyl sulfoxide and hematoxylin have not been reported. To establish the response of neoplastic tissue and cells to this combination of agents, this study was undertaken to determine the effects of dimethyl sulfoxide and hematoxylin on a transplantable lymphosarcoma in mice.