Showing papers by "Bar-Ilan University published in 1970"

The specificity of proteinases from Streptomyces griseus (pronase)

Abstract: Purification of pronase by ion-exchange chromatography gave four proteolytically active fractions. Fraction A 2 contained an endopeptidase that attacks poly l-valine. Fraction B contained an endopeptidase, an aminopeptidase and carboxypeptidases. The activities against hippuryl-L-arginine and hippuryl-L-phenylalanine could be inhibited to a considerable extent by di-isopropyl phosphorofluoridate and by EDTA. Fraction C contained an endopeptidase resembling bovine trypsin. The pure enzyme was completely inactivated by di-isopropyl phosphorofluoridate and pancreatic trypsin inhibitor and to about 90% by other naturally occurring trypsin inhibitors. Fraction D contained an apparently homogeneous endopeptidase, inhibited by diisopropyl phosphorofluoridate, that adsorbed to and hydrolysed elastin. The activity of all these fractions was tested qualitatively against a wide range of small peptides and synthetic substrates.

Immunology of Follicle-Stimulating Hormone and Luteinizing Hormone

Abstract: Publisher Summary This chapter discusses immunology of follicle-stimulating hormone and luteinizing hormone. Although great strides have been made in the last few years due to the introduction of modern physiochemical techniques, absolute purity of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) has not yet been attained. The lack of pure hormones together with the paucity of knowledge concerning their chemical and structural nature have made the immunological investigations of these hormones complicated, and the results are frequently confusing. Principles of immunology have been applied to the development of immunoassays to the quantitative measurement of FSH and LH in pituitary extracts and in body fluids. Furthermore, antigonadotropic sera have been used in in vivo experiments to elucidate the physiological effects of these hormones. When discussing the purposes for which FSH and LH are used in immunological studies, it has to be kept in mind that they have not been isolated in pure form. This implies that antisera obtained following immunization with these antigens contain not only a population of homologous antibodies, but also antibodies to other protein hormones or nonhormonal contaminants.

The Lysosomal Nature of the Anomalous Granules and Chromosome Aberrations in Cultures of Peripheral Blood in Chediak‐Higashi Syndrome

Abstract: In Chediak‐Higashi syndrome (C.H.) the lysosomal nature of the giant granules in white blood cells was demonstrated by their strong fluorescence with acridine orange and by their strong acid phosphatase and esterase activities.

Sodium Fluxes in Excised Citurs Roots under Steady-State Conditions, with Particular Reference to Salinity Resistance

Abstract: Sodium influx and efflux rates from excised Citrus roots were studied. The sodium fluxes in the free spaces of the roots of the salt-sensitive variety Sweet Lime and of the salt-resistant variety Cleopatra Mandarin were very close to each other. On the other hand, the sodium fluxes from intracellular spaces were considerably lower in the roots of variety Cleopatra Mandarin. The experimental findings were evaluated by compartmental analysis and the rate constants of the sodium fluxes calculated. The possible significance of these procedures for the study of salt resistance is indicated.

An apparatus for investigation of heterogeneous reactions in a flow system

Abstract: Es wird eine Apparatur zum Studium heterogener und pyrolytischer Reaktionen in Fliess-Systemen beschrieben, die fur flussige und gasformige Ausgangsstoffe, Reaktionsprodukte sowie fur deren Mischungen geeignet ist.

Glucose-6-phosphate dehydrogenase isoenzymes in blood cells.

Abstract: THE enzyme glucose-6-phosphate dehydrogenase (G-6-PD) exists in several different forms (isoenzymes) in the human erythrocyte, each apparently determined by a different allele at a single locus on the X chromosome. The structural differences between the isoenzymes lead to different enzymatic activities and often render them separable by gel electrophoresis.

Assessment of Gonadotropin Therapy in Male Infertility

Abstract: Male infertility may be produced by genetic, mechanical, infectious, inflammatory or hormonal causes. Correct diagnosis is essential before any therapy is started. In this presentation we will analyze and discuss therapeutic results only in such cases where infertility was presumably due to hormonal factors.

Antigenicity of proteinases from Streptomyces griseus (pronase)

Abstract: The five pronase fractions, A1, A2, B, C (trypsin-like), and D (elastolytic), obtained by ion-exchange chromatography, were found to be antigenically distinct. Antibodies to pronase inhibited the enzymic activity of each of the enzyme fractions. Pronase trypsin and bovine trypsin, although resembling each other in enzymic activity and in amino acid sequence around their active sites, did not cross-react antigenically with, nor was their enzymic activity inhibited by, the respective homologous antibodies. Inactivation of pronase trypsin by complexing with soya-bean inhibitor AA, was not associated with a decrease in capacity to precipitate with its antibody. It is assumed that the antigenic sites are located far enough from the catalytic site of the enzyme to allow it to precipitate immunologically even when the catalytic site was blocked.

An Investigation of Proteohormones by Alternating Current Polarography

Abstract: The behavior of some proteohormones as mixtures of FSH and LH at different proportions and purity was studied by polarography. Proteins which contain groups of -SH and/or -S-S-, develop in an ammoniacal buffer of CoII or CoIII salts a typical double wave, which is believed to be a catalytic wave of hydrogen evolution. It is called a Brdicka double wave. It depends on various parameters such as concentration of the protein, pH, buffer capacity, temperature, height of mercury current, etc. The influence of changing the various parameters on the height of the wave and on the potential of the maximum of the wave height was studied. Comparison was made among the various hormones and with the simple protein human albumin. The measurements were performed by direct current and alternating current polarography. An attempt is made to investigate the mechanisms of each of the two components of the double wave. Hormone preparations, containing different proportions of LH and FSH, could be characterized.

Analysis of the Velocity Field in Plasmas from the Doppler Broadening of Spectral Emission Lines

Abstract: Publisher Summary An emission line broadened by the Doppler Effect represents the envelope of the unresolved displacements of the line caused by the motion of the radiating atoms or ions in the direction of observation. The motion may not be purely thermal but can, in general, be combined with mass motion that in itself can be of two forms—systematic and random. In principle, Doppler broadening provides a simple and fairly accurate means of measuring the temperature of an inaccessible radiating medium. Specifically, when the temperature of hot plasma is to be measured, the contribution to the broadening by mass motion may be considerable in view of the ability of plasma to sustain collective forms of motion. Apart from its general applicability, the kinetic temperature carries with it two other advantages. Although plasma does not behave as a perfect gas, the kinetic temperature scale requires no correction to bring it in line with the thermodynamic scale, provided k is selected as the Boltzmann constant.

Computer science in Israel' s institutions of higher learning

Abstract: Five of Israel's institutions of higher learning have computer centers and teach courses related to computer sciences. There are two undergraduate programs, three master's degree programs, and one doctoral degree program. These programs are described in this paper. In particular, the undergraduate program at Bar-Ilan University, which is based on Curriculum 68, is described in detail. As a background to the descriptions of the Computer Science curricula, there is a general description of the various university computer centers. The Appendix contains a detailed discussion of the computer configurations, student enrollment, administrative position of the center within the universities, and the scientific applications staff, if any, within the centers.

Adsorption and Oxidation of I− and I2 at Solid Electrodes as Functions of the Anode Potential

Abstract: The mechanism of the electrochemical oxidation of I− and I2 at the bright Pt and Au electrodes and at platinized Pt - electrodes saturated with H2 or O2, was investigated by voltammetric and adsorption measurements. I131 was used for adsorption detection. I− is strongly adsorbed and electrochemically oxidized to IO−at the bright electrodes as a function of the anode potential, but relatively weak adsorption takes place at the platinized electrodes. I2 shows an apparent desorption as a function of anode potential.