Browsing by Author "Read, Clark P."
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Item Amino acid transport in Trypanosome gambiense(1974) Hansen, Brian David; Fisher, Frank M.; Read, Clark P.Using C-labeled amino acids, absorption of L-lysine, L-arginine, L-glutamate, L-phenylalanine, L-methionine, L-threonine, L-alanine, and L-glycine were studied. All amino acids appeared to be absorbed by both simple diffusion and mediated systems. Inhibitions produced by analogues indicate 5 possible transport loci. Locus A may have 3 Bites, one which transports lysine and the remaining 2 binding glutamate and arginine. When occupied, the latter 2 appear to stimulate the transport of lysine. Methionine and phenylalanine were shown to bind nonproductively at the lysine transport site. Locus B transports threonine, glycine, and alanine with negligible interaction with the other amino acids studied. This locus is partially Na+-sensitive. Locus C transports glutamate primarily. Locus D has 2 transport sites, one for phenylalanine and one for methionine. Threonine shows slight interaction at this site. Locus E also has 2 transport sites, one for lysine and one for arginine. All 8 amino acids were tested for Na+ sensitivity, with only the amino acids entering at Locus B affected. Further evidence for Na+ sensitivity of Locus B was demonstrated in that the uptake of threonine, glycine, and alanine was ouabain-sensitive. The uptake of methionine and phenylalanine was measured in the presence of an amino acid mixture and the observed values agreed with those predicted by calculation according to the technique of Read et al. (1963).Item Effects of Carbon Dioxide on Glucose Incorporation in Flatworms(Rice University, 1976-10) McDaniel, James S.; MacInnis, Austin J.; Read, Clark P.; Electronic version made possible with funding from the Rice Historical Society and Thomas R. Williams, Ph.D., class of 2000.Item Localization of trehalose synthesis and degradation in Ascaris(1963) Feist, Carol Fay; Read, Clark P.Tissues of Ascaris lumbricoides (variety suum), the large round worm of pigs, contain trehalose, a disaccharide composed of two molecules of glucose. Minces of various Ascaris tissues were incubated with C14glucose to determine the site of trehalose synthesis. Chromatography and radioautography were used to identify C14trehalose synthesized during the incubation period. It was found that the reproductive tissues of both male and female Ascaris possess a mechanism for trehalose synthesis. Intestinal tissue and muscle showed no capability for trehalose synthesis under conditions of the incubation. By incubation of Ascaris tissue homogenates with commercial trehalose it was found that only intestinal tissue was capable of hydrolyzing trehalose into two molecules of glucose. The significance of synthesis and degradation of trehalose is discussed with regard to the findings of previous investigations.Item Status of Behavioral and Physiological "Resistance"(Rice University, 1958-04) Read, Clark P.; Electronic version made possible with funding from the Rice Historical Society and Thomas R. Williams, Ph.D., class of 2000.Item Studies of the carbohydrate and related metabolism of the cestode, Hymenolepis diminuta(1950) Read, Clark P.This study was initially undertaken to determine whether the role of phosphorus in the carbohydrate metabolism of tapeworms is similar to or different from the role of this element in the chemical economy of other animals. A study was also made of the overall carbohydrate utilization as indicated by some of the end products, and of some aspects of the electron transfer mechanism at the "terminal end" of the carbohydrate metabolism.Item Studies on amino acid absorption in cestodes(1963) Senturia, Jerome B; Read, Clark P.The kinetics of absorption of L-methionine-methyl-C14 by Hymenolepis citelli were studied using short term incubations. The absorption was shown to follow saturation kinetics. No significant differences were shown between the L- and D- forms of methionine absorption. Fifteen amino acids were found to be inhibitors of methionine absorption. This inhibition was demonstrated to be competitive in nature. Inhibition constants were calculated for all the inhibitors. It was shown that a mixture of amino acids produced a competitive inhibition of methionine-methyl-C14 absorption which could be predicted from the inhibitions produced by the individual amino acids (by the equation of Read et al, 1962, J. Parasit. 48:46 abst.). It is suggested that an amino group alpha to the carboxyl group and a non-polar side chain are the requirements for absorption in this system under the conditions tested. The results are discussed briefly in terms of the ecology of H. citelli.Item Studies on cell synthesis in mixed microbial populations; log phase innocula and total oxygen demand(1962) Shivajirao, Tipirneni; Busch, A. W.; Hellums, J. David; Read, Clark P.A study of the effects of a log-phase seeding technique and of the oxidative assimilation relations, in soluble substrates, of mixed cultures of bacteria and protozoa, as found in a typical domestic waste water, was conducted in the Environmental Engineering Laboratory of the Rice University during the 1961-1962 academic year. These studies were part of a broad investigation of the study of the Biochemical Oxygen Demand Progression in soluble substrates. This is believed to be the first work using the log-phase seeding technique in shortening the time to the plateau in oxygen utilization and in the formulation of oxidative assimilation relationships in mixed microbial populations. Previous work on the effects of log-phase seeding and microbial assimilations generally utilized pure cultures and heavy innocula of bacteria with short incubation periods. Substrates studied in this investigation were glucose, glutamic acid, a (1:1) mixture of glucose and glutamic acid, aspartic acid, acetic acid, propionic acid, and lactose. Both Warburg and dilution techniques were utilized. The log-phase seeding technique produced a marked reduction in lag for all of the substrates and a reduction in time to reach the plateau for lactose, glutamic acid, aspartic acid, and propionic acid. The general pattern of the progression of biochemical degradation of soluble substrates in shown in graph form. The plateau in oxygen utilization was highly reproducible and was characteristic for a specific substrate. Based on the data obtained, oxidative assimilation equations were developed for the substrates under study. Theoretical plateaus occurred at 41, 40, 39, 44, 50, 52, and 41 per cent of the theoretical oxygen demand in the case of glucose, a (1:1) mixture of glucose and glutamic acid, glutamic acid, aspartic acid, acetic acid, propionic acid, and lactose, respectively. The nitrogqp supplied by the standard dilution technique for B.O.D. analysis is adequate for glucose and lactose concentrations only up to 8mg/l. At the concentrations of 12.1 mg/10 utilized in this study, the resulting nitrogen deficiency yielded low values for the plateau in oxygen uptake normally representing completion of synthesis.Item Studies on plasma membrane protein in a Neurospora crassa mutant(1967) Chang, Merry Chin-Mei; Read, Clark P.After a review on studies on membrane structural protein, the purpose of isolating plasma membrane protein in a Neurospora crassa mutant was stated. An aggregate containing protein, lipid and carbohydrate with high content of amino acids with non-polar side chains and low content of aspartate and glutamate has been isolated and studied with gel filtration, electrophoresis and amino acid analysis techniques. It has a molecular weight of about 2,00,000 as estimated by gel filtration. From amino acid analysis, a lipid-carbohydratefree subunit has been calculated to have a molecular weight of 63,500. According to the calculation, the aggregate contained 14 subunits.Item Studies on the biology of a rabbit adapted strain of the human body louse(1960) Gooding, Ronald H; Read, Clark P.Item The effects of pyridoxal and ammonium ion on the active transport of methionine and other amino acids in H. diminuta(1965) Colthart, Linda Day; Read, Clark P.The uptake and accumulation of methionine and other amino acids in the cestode H. diminuta is studied with respect to the influence of pyridoxal, pyridoxine, and ammonium ion. It is found that neither pyridoxal nor pyridoxine exert any measurable effect upon the initial velocity or the total amount of uptake of methionine. Concentrations of pyridoxal and pyridoxine ranged from .005 mM to 1.0 mM, and concentrations of methionine ranged from .05 mM to 1.0 mM. Ammonium ion is found to exert a very significant effect on the total accumulation of methionine and several other amino acids but no effect on the initial velocity of uptake. The ammonium ion affects accumulation in two ways: First it increases production of a particular metabolite within the worm which is composed partly of methionine and certain other amino acids. Production of this metabolite in turn decreases the amounts of constituent amino acids in the worm' s amino acid pool, thereby allowing for an increased apparent accumulation of those amino acids. The second way the ammonium ion affect accumulation is by inhibiting efflux of some of the neutral amino acids, particularly methionine and alanine. It can exert is inhibitory effect when present only in the efflux medium or only in the worm and not in the efflux medium, or when present both within and without the worm. An attempt to explain this unusual effect is made by postulating a new transport mechanism.