Biophysics Commons^™

Using Xenon As A Heavy Atom For Determining Phases In Sperm Whale Metmyoglobin, Jacqueline Vitali, Arthur H. Robbins, Steven C. Almo, Robert F. Tilton

Physics Faculty Publications

Xenon gas can be used as a heavy atom for determining phases in a protein. We demonstrate that an interpretable electron density map can be obtained for sperm whale metmyoglobin from a single xenon derivative using iterative single isomorphous replacement with the anomalous scattering method.

Characterization Of Two Temperature-Sensitive Mutants Of Escherichia Coli Exhibiting An Altered L22 Ribosomal Protein, Bonnie A. Burnette-Vick

Electronic Theses and Dissertations

Analysis of E. coli strains SK1047 and SK1048 have shown them to be temperature-sensitive, protein-synthesis deficient. An alteration in ribosomal protein L22 was detected in both strains using two dimensional gel electrophoresis. Protein L22 was purified from both strains by reversed phase high performance liquid chromatography and from two dimensional electrophoretic gels. Purified ribosomal protein L22 was labeled by reductive methylation and used in 23S RNA binding assays with and without ribosomal protein L4. At the permissive temperature, protein L22 from SK1047 bound less efficiently than the control while protein L22 from SK1048 bound as efficiently as the control. At …

Action Of Heptaminol Hydrochloride On Contractile Properties In Frog Isolated Twitch Muscle Fibre, Bruno Allard, Vincent Jacquemont, Fouad Lemtiri-Chlieh, Bernard Pourrias, Oger Rougier

fouad Lemtiri-Chlieh

1 Heptaminol stopped or delayed the progressive decline in tension which characterizes the phenomenon of fatigue in frog isolated twitch muscle fibre. 2 Heptaminol had no action on the sodium, potassium and calcium voltage-dependent ionic conductances. 3 The hypothesis of an action via an internal alkalinization was tested by comparison with the action of NH4Cl. Both substances increased the tension. 4 The action of hepataminol was suppressed in sodium-free (TRIS) solution or in the presence of amiloride while the action of NH4Cl was always observed. 5 These results could be explained by a stimulation of the Na/H antiport by heptaminol.

Domains And Anomalous Adsorption Isotherms Of Dipalmitoylphosphatidylcholine Membranes And Lipophilic Ions: Pentachlorophenolate, Tetraphenylborate, And Dipicrylamine, Pavel Smejtek, S. Wang

Physics Faculty Publications and Presentations

Dipalmitoylphosphatidylcholine (DPPC) vesicles acquire negative surface charge on adsorption of negatively charged pentachlorophenolate (PCP-), and lipophilic ions tetraphenylborate (TPhB-), and dipicrylamine (DPA-). We have obtained (a) zeta-potential isotherms from the measurements of electrophoretic mobility of DPPC vesicles as a function of concentration of the adsorbing ions at different temperatures (25–42 degrees C), and (b) studied the effect of PCP- on gel-to-fluid phase transition by measuring the temperature dependence of zeta-potential at different PCP- concentrations. The zeta-potential isotherms of PCP- at 25, 32, and 34 degrees C correspond to adsorption to membrane in its gel phase. At 42 degrees C the …

Adsorption To Dipalmitoylphosphatidylcholine Membranes In Gel And Fluid State: Pentachlorophenolate, Dipicrylamine, And Tetraphenylborate, Pavel Smejtek, S. R. Wang

Physics Faculty Publications and Presentations

We measured the dependence of electrophoretic mobility of dipalmitoylphosphatidylcholine (DPPC) vesicles on the aqueous concentration of negatively charged ions of pentachlorophenol (PCP), dipicrylamine (DPA), and tetraphenylborate (TPhB). The objective was to determine how the physical state of hydrocarbon chains of lipids affects adsorption of lipophilic ions. The studies were done at 25 and 42 degrees C to determine adsorption properties of DPPC membrane in the gel and fluid state, respectively. From the analysis of zeta-potential isotherms in terms of Langmuir-Stern-Grahame model we obtained the association constant, K, the area of the adsorption site, Ps, and the linear partition coefficient, beta. …

Kinematic Considerations Of Elite Alpine Slalom Ski Racers, David Andrew Goodwin

Masters Theses

This study described specific kinematic parameters associated with success on the international level in alpine slalom ski racing. Sixteen male athletes representing twelve countries comprised the subject pool. Subject selection was based on finish position in the men's special slalom at the 1989 World Alpine Ski Championships in Vail, Colorado. Cinematographical records were analyzed by a method known as direct linear transformation.

The findings of the study indicated that: (a) hip and knee joint angles of the turning leg must approximate 1.80 to 1.83 radians and 1.82 to 2.21 radians, respectively, for efficiency in this turn; (b) a decrease in …

Rotational Symmetries Of Nuclear States: Spin Determinations In Advanced Laboratory, Wilfred J. Braithwaite

Journal of the Arkansas Academy of Science

An advanced laboratory experiment is described which shows the connection between the rotational symmetries of nuclear states and the assignments of spins to discrete nuclear states. Standard angular correlation methods were used to study the two sequential gamma ray transitions in each ⁶⁰Ni nucleus, populated by unobserved beta decays from a weak radioactive ⁶⁰Co source. The chosen electronics and detectors were inexpensive and easy to operate. This experiment was extended to introduce students to real-world data acquisition, using finite-geometry detectors, which resulted in enormously larger coincident data rates.

Conformational And Circular Dichroism Studies On N-Acetyl-L-Prolyl-D-Alanyl-Methylamide, S. Ramaprasad

Journal of the Arkansas Academy of Science

The compact ordered conformations of the molecule N-Acteyl-L-Prolyl-D-Alanyl-Methylamide have been studied by semiempirical energy calculations in vacuum and circular dichroism (CD) in solution. The presence of ordered structure has been observed in hydrogen bond promoting solvents like trifluoroethanol by CD studies. In hydrogen bond breaking solvents, like trifluoroacetic acid (TFA), significant fraction of the ordered conformers probably assume extended conformation without intramolecular hydrogen bonds and perhaps are in equilibrium with the fraction of compact ordered structures. The trend observed in going from nonpolar to polar solvent is also compatible with the previous NMR studies in solution. The semiempirical energy calculations …

Presence Of A Cs-Resistant Transient Outward Current Which Distorts Ica Measurements In Guinea-Pig Single Ventricular Cells, Georges Christé, Brigitte Delachapelle, Fouad Lemtiri-Chlieh, Carlos Ojeda

fouad Lemtiri-Chlieh

To correctlyr analyse the physical properties of ion channels and the actions of drugs upon them, it is important that the membrane conducts only the ionic species believed permeant. In guinea-pig ventricular cells it has been assumed that only ICaL flows in the potential range -50 to +60 mV in the presence of intra- and extracellular Cs (> 20 mM). We report here that this is not the case due to the presence of a Cs-insensitive, transient outward current.

Measurements Of Cytosolic Free Ca In Cultured Rat Neonate And Adult Guinea-Pig Ventricular Cardiac Myocytes, Jean-Claude Bernengo, Fouad Lemtiri-Chlieh, Carlos Ojeda, Nadine Pltonoff

fouad Lemtiri-Chlieh

Cytosolic free Ca was measured with Indo-1 (Grynkiewicz et al. 1985) as free acid (in guinea-pig cells) or as the ester (in rat neonate cells). Using image analysis we obtained concentration maps at 40 ms intervals at two wavelengths (Cannell et al. 1986). In rat neonate cells, at rest and during contraction, calcium was apparently non-uniformly distributed, in contrast to guinea-pig adult cells. Using a dual PM spectroscopic system adapted to an inverted microscope we found: (1) the conversion of Indo-AM to Indo- 1 in the cytosol is not complete (< 40% contribution to the total light); (2) rat neonate cells buffer Ca (at rest 130-170 nM) only for [Ca]. between 1 and 3 mM, whereas in adult guinea-pig cells the range extended to 10 mM; (3) during contraction [Ca]i rose from 200 nm to no more than 1 microM. Digitoxin increases basal and peak [Ca]i; (4) during spontaneous contractions, in guinea-pig cells, [Ca]i rises from 70 to 200 nm when [Ca]o = 0, and from 170 nm to about 1 microM when [Ca]o = 2 mM; (5) in voltage-clamp conditions the rise in [Ca]i does not exceed 2 microM and oscillations occur in the presence of forskolin. When loading with Indo-1, cells frequently cease to contract (Powell et al. 1988) and the variations in [Ca]i are then very small (about 200 nm at peak ICa). In both cases these values are small compared to the total charge crossing the membrane.

The Water Vapor Conductance Of Squamate Reptilian Eggs: The Influence Of Scaling On Nesting Ecology., Louis A. Somma

Papers in Herpetology

Flexible-shelled eggs of squamate reptiles are strongly influenced by their surrounding microclimate, particularly the hydric conditions of the nest. The eggshell water vapor conductance of an egg can be an indication of its requirement for water from the nest. Ackerman et al. (1985. Physiol. Zool. 58:129-137) have described the scaling relationship for eggshell water vapor conductance (G_H2O) of flexible-shelled reptilian eggs (G_H2O = 981.8M^0.52). This scaling relationship was investigated with water vapor conductance data obtained from 8 species of lizards representing the families Iguanidae (Anolis carolinensis, A. sagrai, Sceloporus woodi, S. virgatus) …

The Synthesis And Evaluation Of 5-Phenyloxazolidines As Potential Cardiovascular Drugs, Tammy C. Wang

Chemistry & Biochemistry Theses & Dissertations

Drugs such as adrenoceptor antagonists and certain centrally acting agents are known to lower blood pressure and thus serve as clinically useful antihypertensive agents. Norepinephrine 4, a natural ∝-adrenoceptor agonist, is the major agent associated with increased blood pressure in the periphery. Based on a careful structure-activity comparison, a series of substituted oxazolidines, 20, 21, 22 and 23, have been designed as possible antihypertensive candidates. Specifically, 22 and 23 have been synthesized to serve as potential norepinephrine antagonists.

Preliminary evaluation of these compounds indicated that they were not antihypertensive in nature. The more active compound, 23, …

A Pesquisa Urbana No Equador, Fernando Carrión Mena

Fernando Carrión Mena

É relativamente difícil precisar a origem cronológica de um campo ou área de conhecimento de um país determinado. Ainda mais se tem em conta que tanto a constituição teórica de um campo de conhecimento ultrapassa as fronteiras nacionais, como o objeto empírico de estudo é anterior a sua constitui9ao teórica. Isto é, precede-a e é uma condição necessária porém insuficiente. Para o nosso caso, este objeto é a "cidade", que historicamente existe no Equador, segundo algumas hipóteses desde á conquistam espanhola (Carrión, F. 1986); no entanto um pensamento relativamente consistente sobre ela recém se inicia quando o processo de urbanização …

Plasma Corticosterone Levels In Cholesterol-Fed Cockerels Before And After A Twenty Minute Run, Stanley N. David, Clarene L. David

Journal of the Arkansas Academy of Science

Cockerels were exercised to observe the influence of physical activity on plasma corticosterone concentrations. The birds were maintained on a commercial mash or on an atherogenic diet. Plasmas were collected on the first day, fifteen days after the first collection and immediately after a 20 minute run on that fifteenth day. The plasma corticosterone levels as determined by radioimmunoassay showed extreme variations within collections. Hence, the data analysis indicated no significant changes of the Compound β in the blood of the cockerels due to diet, or exercise or the combination of both. The causes for the wide variation of plasma …

Concanavalin A-Nonbinding Enzymes Of Crotalus Scutulatus Scutulatus Venom, C. K. Childs, Michael W. Hinson, Dewey H. Sifford, Bob D. Johnson

Journal of the Arkansas Academy of Science

Crotalus scutulatus scutulatus crude venom was separated into two fractions by Concanavalin A Sepharose 4B affinity chromatography. The Concanavalin A-nonbinding fraction (F-l) exhibited phosphomonoesterase (orthophosphoric monoester phosphohydrolase EC 3.1 .3.2), phosphodiesterase, 5 '-nucleotidase (5 '-ribonucleotide phosphohydrolase EC 3.1.3.5), phospholipase A (phosphatidate 2-acylhydrolase EC 3.1.1.4), hyaluronidase (hyaluronate glycanohydrolase EC 3.2.1.d), N-benzoyl-Larginine ethyl esterase, p-toluenesulfonyl-L-arginine methyl esterase, L-amino acid oxidase (L-amino acid: O2 oxidoreductase [deaminating] EC 1.4.3.2), and caseinolytic activities. Thrombin-like and NAD nucleosidase (5 '-ribonudeotide phosphohydrolase EC 3.1.3.5) activities were not observed. DEAE Sephadex A-50 ion exchange chromatography by two stage elution of F-l yielded several fractions having proteinase activities. Proteinase …

Role Of Centriolar Matrix And Striated Rootlets In Centriolar Pairing And Orientation During Spermatogenesis In Hydractina Echinata, Maurice G. Kleve

Journal of the Arkansas Academy of Science

Transmission electron microscopy of the spermatogenic stages of the hydroid, Hydractinia echinata, reveals a series of complex structural and positional changes in the centrioles of spermatocytes and spermatids. The newly generated centriolar pairs of spermatocytes form an unusual four-centriole aggregate that persists until cell division. The distal centrioles of this aggregate are shrouded with a very dense matrix that accumulates after centriolar replication. This matrix facilitates the mechanical attachment between distal centrioles and microtubular nucleating satellites, striated rootlets and pericentriolar processes. The association of these accessory structures occurs sequentially and is repeated in spermatocytes and spermatids. An electron dense plaque, …

Repair Of Lethal Damage Induced In A Hamster X Amphibian Hybrid Tissue Culture Cell Line By Ultraviolet Light And Gamma Ray, Susan Kulp, Ann Page, H. Gaston Griggs

Journal of the Arkansas Academy of Science

A hybrid cell line was formed by fusing cells from two established vertebrate tissue culture cell lines (V79B1 hamster and A84 Xenopus), which were known to differ substantially in resistance to some radiation-induced lesions and in associated repair potential. Ultraviolet and gamma ray dose-survival relations were then determined and analyzed for the three cell lines, primarily to compare the radiosensitivity (Do dose) of the hybrid line with that of each parental line for each radiation. Further experimentation was conducted to determine the extent to which observed differences in these Do doses could be attributed to interactions of the combined parental …

Effects Of Gamma Radiation On Salix Nigra Marsh Cuttings, Roy Z. Gehring

Journal of the Arkansas Academy of Science

Dormant cuttings of Salix nigra Marsh, were exposed to gamma radiation from a cobalt-60 source at a dose rate of 1110 roentgens (r) per minute. Exposure doses ranged from 50 r through 100 Kr with 100% mortality at 10 Kr. Low doses of ionizing radiation apparently stimulated growth, while higher doses progressively retarded growth. The growth of the staminate catkins was inversely proportional to total exposure dose (increased dose resulted in progressively decreased growth). Determination of growth rates at different intervals post-irradiation indicated recovery of the surviving fraction of the irradiated cuttings. At ninety days, the highest growth rate occurred …

Computer Pattern Recognition Of Action Potentials, Ronald S. Remmel

Journal of the Arkansas Academy of Science

A general method of pattern recognition was applied to the problem of recognizing extracellularly-recorded neuronal action potentials in the presence of noise and other pulses. A PDP1 1/23 performed the calculations. There were four stages: 1.) A bandpass filter attenuated noises; 2.) the data input program digitized the signal every 55 μsec. If the signal exceeded a threshold, 12 samples of the signal and the time were written onto the disk; 3.) the pulse discriminating program recognized an action potential by fitting the 12 points with this function: v(t) = (a + bt + ct² ) exp(-t/Ƭ). For each pulse …

Effects Of Pulsed Electric Fields On Mammalian Cell Membranes, Guy K. Smith

Theses and Dissertations

The effect of pulsed electric fields on cell membranes were studied to investigate the effects of an electric field, per se, on biological systems, without the densometric and other technical problems associated with other forms of nonionizing radiation. Exposure of mouse splenocytes to a high voltage pulse resulted in an increase in membrane permeability to K⁺ that was dependent on both the electric field strength and the pulse duration. Exposure to a 2 μsec, 3.0 kV/cm pulse elicited a 50% loss of intracellular K⁺ indicating that the critical transmembrane potential (V_m) at breakdown was 1.26 volts …

Effects Of Glucocorticoid Treatment On The Properties Of Single Notor Units In Cat Hindlinb Huscles, Andrew James Robinson

Theses and Dissertations

The administration of glucocorticoids has been shown to induce atrophy and weakness in whole skeletal muscle. These effects frequently appear to be more pronounced in pale muscle than in red muscle. The present study was undertaken to examine the effects of steroid treatment on the contractile, electrical, and fatigue properties of single meter units in pale and red cat hindlimb muscles. Single motor units in the medial gastrocnemius (MG) and soleus muscles were isolated using techniques developed by McPhedran, et al., (1965). The properties of a large number of motor units were examined in normal animals and were compared to …

A Spectrographic Method For Determination Of Lead In Human Blood Utilizing The Far Ultraviolet Wavelength Region, Marianne Oriel Lull

Masters Theses

No abstract provided.

Model For Estimating Soil Water Flow, Water Content, Evapotranspiration And Root Extraction, Musa N. Nimah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A mathematical model was developed to predict water content profiles, evapotranspiration, water flow from or to the water table, root extraction and root water potential at the surface as functions of time under unsteady state conditions.

The model was tested in the field at The Hullinger Farm near Vernal, Utah, in 1970 and 1971. Comparison of water content-depth profiles show excellent agreement at the end of a 9- day run in 1970 on oats seeded to alfalfa. In 1971 with alfalfa as the crop, the data show best agreement, between predicted and computed water content-depth profiles, 48 hours after any …

The Effects Of Total Body Proton Irradiation On The Peripheral Plasma Corticosterone Concentration And The Ultrastructure Of The Zona Fasciculata In Mus Musculus, Robert James Young

Dissertations, Theses, and Masters Projects

No abstract provided.

Mathematical Model Of Placental Oxygen And Carbon Dioxide Exchange, Ester P. Hill

Loma Linda University Electronic Theses, Dissertations & Projects

This model of placental CO₂ and O₂ exchange calculates the time course of changes in P_^CO2, [HCO₃^-], and [H⁺] in each of four "compartments" of placental exchange vessels: maternal erythrocytes, maternal plasma, fetal plasma and fetal erythrocytes. The changes in hemoglobin-bound CO₂ (carbamate) and oxyhemoglobin contents within the erythrocytes are also calculated, permitting consideration of the Haldane and Bohr effects. Equations were written to represent one-dimensional steady state CO₂ and O₂ diffusion between concurrent maternal and fetal capillaries and the subsequent hydration, carbamino and oxyhemoglobin reactions. The equations …

Rapid Electroosmosis Measurements, James O. Wear

Journal of the Arkansas Academy of Science

A cell has been designed and built that allows for rapid measurement of volume moved in a definite time by electroosmosis. The cell is simple to use and is not very elaborate. Using a water jacket, the cell temperature can be controlled to ± 0.1° C. Measurements are presented for acetonitrile, dimethylformamide, and nitrobenzene at 25° C for applied voltages of 25, 50, 75, and 100 volts.

Effects Of High-Energy X-Rays On The Reproduction Of Urosalpinx Cinerea, Kenneth Allen Leon

Dissertations, Theses, and Masters Projects

No abstract provided.