HEBREW UNIV JERUSALEM (Israel)Overview
Publication Timeline
Most widely held works by
HEBREW UNIV JERUSALEM (Israel)
Proteases of Stored Product Insects and their Inhibition by Specific Protease Inhibitors from Soybeans and Wheat Grain
(
Book
)
5 editions published between 1987 and 1989 in English and held by 2 libraries worldwide The research covered by the first Interim Report primarily was devoted to detection, isolation and characterization of digestive proteinases of the rust red flour beetle (Tribolium castaneum), the mealworm (Tenebrio molitor), and the locust (Locusta migratoria). Recently, the latter has been posing a serious threat to valuable crops in different parts of the world. The detection of trypsin- and chymotrypsin-like enzymes in the midgut of Tribolium castaneum larvae suggests that this insect may be susceptible to inhibition by naturally-occuring trypsin- and chymotrypsin-inhibitors. The findings that trypsin and chymotrypsin from the digestive tract of Tenebrio adults differ in amino acid composition from the respective larval enzymes indicates that the composition and consequently, the structure of the proteolytic enzymes in the adult do not remain the same as in the larva after metamorphosis.
Transgenic Engineering of Cholinesterases: Tools for Exploring Cholinergic Responses
(
Book
)
3 editions published between 1998 and 1999 in English and held by 2 libraries worldwide The long-term objective of the research in the laboratory is to understand the molecular and cellular mechanisms that mediate the coupling of short-term changes in cholinergic neurotransmission to long-term consequences in motor, cognitive and autonomous functions. To study the pathways by which cholinergic inputs control neuritic and synaptic cytoarchitecture and determine changes in downstream-regulated genes, we have developed transgenic and antisense models which enable gain- and loss-of-function modulation in several acetylcholinesterase (AChE) variants. These led to the observation that AChE expression is essential for growth and affects synaptic development through its catalytic function, core protein and variable-termini domains. In transgenic mice, we found that overproduction alters expression of the neuronal circuitry-related members of the neurexin gene family and causes late onset, progressive deterioration in dendrite branching, neuromotor and cognitive faculties. Using hippocampal brain slices and an in vivo stress protocol, we demonstrated that both acute stress and exposure to anti-cholinesterases disrupt the blood-brain barrier and promote long-lasting changes in cholinergic gene expression. Currently, cosmid sequencing and genotyping studies are being employed to explore the association of intragenic and neighboring sequences with regulation of the expression of the AChE gene, which is essential for responses to drugs and scavenging of poisons.
18TH Annual Meeting of the European Neuroscience Association
(
Book
)
2 editions published in 1996 in English and held by 2 libraries worldwide The Final Proceedings for 18th Annual Meeting of the European Neuroscience Association, 3 September 1995 - 7 September 1995. RNA editing alters drug responses to AMPA receptors, Cis-trans regulation of Target genes for neurocognitive drugs, Endogeneous cacabinoid ligands in the central nervous system and in the periphery, Recimbinant acetylcholinesterase as a drug scavenger.
Development Novel Subwavelength Light Sources and Lasers
(
Book
)
2 editions published in 1998 in English and held by 2 libraries worldwide With the help of the support we have received from the United States Advanced Research Projects Agency through the United States Army our laboratory has pioneered lensless near-field optics. The optical resolution that has been achieved with this novel advance has already carried optics to a new frontier of resolution in the range of tens of nanometers. These studies have indicated that the ultimate resolution that could be achieved with this new direction in optics could even approach the dimension of a single atom or molecule. Thus, the barrier of optical resolution has been broken by the revolution that has occurred as a result of the development of near-field optical imaging. Near-field optics elegantly bridges both exciting fundamental research and a wide variety of practical applications. These applications portend a relatively transparent integration of near-field optical technology with currently available far-field optical techniques to overcome the solid brick wall of resolution that many of these optical applications now experience.
Sixth International Conference on Composite Interfaces
(
Book
)
2 editions published in 1996 in English and held by 2 libraries worldwide The Final Proceedings for Sixth International Conference on Composite Interfaces, 5 May 1996 - 8 May 1996 Molecular interactions at interfaces, Structural Characterization, Theoretical aspects of the interfaces/interphases, interfacial adhesion: theory and applications, surface characterization techniques, surface treatments.
Hyperfine interactions in the ground state and first excited state of dy161 in dysprosium iron garnet
(
Book
)
1 edition published in 1961 in English and held by 2 libraries worldwide The hyperfine Zeeman splittings in the recoilfree absorption spectrum of the 26 kev gamma ray from Dy-161m in Dy-161 situated in dysprosium iron garnet have been observed. At 85 K, the magnetic hyperfine interactions of the ground state and first excited state of Dy-161 are -400 + or - 40 mc and 455 + or - 40 mc, respectively. The electric quadrupole interactions (eqQ/4) at this temperature are 120 + or - 30 and 90 + or - 30 mc, respectively. At 300 degrees K the effective magnetic field (H sub eff) is 4.6 times smaller, and illustrates the proportionality between H sub eff and spontaneous magnetization of the Dy sub-lattice. Assuming Parks value of -0.37 + or - 0.05 nm for the Dy-161 ground state magnetic moment, H sub eff (85 K) equals 3.5 x 10 to the 6th power oe, and 0.42 + or - 0.08 nm for the magnetic moment of the first excited state were obtained. At 300 K a quadrupole interaction of less than 20 mc was obtained. The strongly temperature dependent quadrupole interaction is interpreted as being largely due to the effective electric field gradient produced at the nucleus by the 4f electrons which should be partially aligned below the Curie temperature. (Author).
Genetic and Epigenetic Mechanisms Underlying Acute and Delayed Neurodegenerative Consequences of Stress and Anticholinesterase Exposure
(
Book
)
4 editions published between 2000 and 2003 in English and held by 1 library worldwide The effect of stress and exposure to anti-cholinesterases on the cholinergic system were tested in vitro and in vivo. Rapid muscle fatigue was identified and electrophysiologically characterized in mice with elevated levels of AChE-S, the synaptic variant of acetylcholinesterase (AChE). Anxiety responses were observed in mice that over-expressed the stress-associated variant, AChE-R. The binding partner of AChE-R in mouse neurons was identified as a component of the protein kinase-C signaling system. The role of AChE-R in the symptoms of experimental myasthenia gravis in rats has been documented. As the response to chronic exposure to organophosphate anticholinesterases provokes a stress-like response from the cholinergic system, the effect of such exposure in humans on electroencephalographic abnormalities and their origin in the brain was studied. Future research will be assisted by the development of an anti-AChE-S polyclonal antibody, and a mouse strain that produces an endogenous anti-AChE-R antisense reagent upon feeding of doxycycline. These experiments are building a case for the involvement of unregulated AChE-R production in long-term stress response.
Development of Protective Agent Against Sulfur Mustard-Induced Skin Lesions
(
Book
)
4 editions published between 1999 and 2005 in English and held by 1 library worldwide Sulfur mustard(SM) is a potent vesicant employed as a chemical weapon in various conflicts during the 20th century (1,2). It functions as a powerful alkylator and highly cytotoxic blisterogen in both humans and animals (1-9). Skin exposed to SM develops erythema within 30 minutes to several hours after exposure followed by edema, vesicle and blister formation, ulceration, necrosis and desquamation (2,7,8,10). The severity of lesions observed after exposure to SM has emphasized the need for an efficient pharmacological antidote against its vesicating activity. The powerful alkylating activity of SM(11-13) results from its conversion, in aqueous solution, to the highly electrophilic ethylene episulfonium derviative (2) which can be neutralized by nucleophilic agents.
Studies on the Molecular Dissection of Human Cholinesterase Variants and their Genomic Origins
(
Book
)
2 editions published between 1995 and 1996 in English and held by 1 library worldwide Research has been focused on the human cholinesterase genes, their variant protein products and the biological roles of these proteins in different tissue - and cell types. To elucidate the biochemical properties and biological functions of this large array of ChE variants, we employed microinjected oocytes and transiently transgenic embryos of Xenopus laevis. This has led to the demonstration that the C-terminal peptide characteristic of the brain and muscle form of acetyicholinesterase (AChE) and butyrylcholinesterase (BuChE) leads to synaptic targeting of these enzymes. Moreover, we were able to show that AChE exerts a morphogenic action on synapse development. The biochemical and biological functions of the BCHE gene and its BuChE protein product were approached by a combination of Xenopus oocyte expression and molecular genetics. Substitution of Asp at position 70 in BuChE by Gly creates an enzyme incapable of hydrolyzing succinylcholine, unlike the native enzyme. This structure-function relationship explained the known clinical syndrome of "succinylcholine apnea". The next step was to replace the BuChE peptide harboring Asp70 with that of AChE. This introduced charge modification in the resultant active chimera and explained many of the differences between AChE and BuChE with respect to drug and poison sensitivities. A population diversity study revealed 11% heterozygotes for Asp/Gly70 among Israelis and shed new light on individual variabilities noted for the newly tested anti-AChE drugs, examined for their potential in Alzheimer's therapy. Our current efforts are to extend these studies to elucidate the protective roles of these proteins against organophosphate intoxication, using transgenic mice overexpressing the human ACHE gene.
Molecular Biological Studies on the Biogenesis of Human Cholinesterases in vivo and as Directed by Cloned Cholinesterase DNA Sequences
(
Book
)
2 editions published between 1989 and 1990 in English and held by 1 library worldwide Acetylcholinesterase (ACHE) is an enzyme long noted for its essential role in the termination of neurotransmission at cholinergic synapses and neuromuscular junctions. Because acetylcholinesterase is the target protein for a variety of neurotoxic compounds, including natural poisons, common agricultural insecticides, and chemical warfare agents, research on this enzyme in man has profound implications for human health and well-being. Together with the related but distinct protein butyrylcholinesterase (BCHE), it presents an intriguing model for the basic scientific study of tissue-specific and differential regulation of gene expression employing divergent pathways in protein biosynthesis.
Energy Transfer between Inorganic Ions in Glasses
(
Book
)
2 editions published between 1974 and 1975 in English and held by 1 library worldwide Absorption and fluorescence spectra of Er(3+) in germanate and tellurite glasses were obtained. Spontaneous transition probabilities were calculated using the Judd-Ofelt theory and intensity parameters obtained from measured integrated absorption coefficients. Quantum efficiencies of the fluorescences were measured by the comparative method and by the use of measured decay times. Multiphonon relaxation rates were calculated using the experimental data. Radiative transition probabilities from energy levels of Tm(3+) in glasses were calculated using the matrix elements obtained by intermediate coupling schemes and experimentally obtained intensity parameters. Nonradiative transition probabilities in different glass hosts were calculated. Quantum efficiencies of luminescence of rare earth in glasses can be predicted. Absorption and Fluorescence spectra of Sm(3+) were measured in GeO2, ternary germanate and borax glasses. From these the intensity parameters were calculated by use of Judd-Ofelt formula. Visible emission and decay times of Sm(3+) and its relative quantum efficiencies were measured.
RESEARCH ON OPTICS OF SELECTIVE SURFACES
(
Book
)
2 editions published between 1959 and 1960 in English and held by 1 library worldwide The feasibility of improving the performance of solar heat collectors by applying the principles of selective radiation is discussed. Electroplated black nickel deposits gave the best results. The chemical composition, structure, optical properties, mathematical interpretation, AND MODELS OF BLACK NICKEL DEPOSITS WERE INVESTIGATED. The conclusions are summarized.
RESEARCH IN THE AREA OF MATHEMATICAL ANALYSIS
(
Book
)
2 editions published between 1961 and 1962 in English and held by 1 library worldwide The investigations of the mathematical analysis research group during the contract year (1960/61) are described.
Membrane Fluidity and Shape of Human Red Blood Cells are Altered by Physiological Levels of Hydrostatic Pressure
(
Book
)
1 edition published in 1994 in English and held by 1 library worldwide The effect of hydrostatic pressure at physiological levels, such as that applied to humans in diving or hyperbaric chamber, on human red blood cell (RBC) membrane fluidity and morphology was studied. Membrane fluidity was determined by fluorescence anisotropy (FA) of lipid probes (mainly diphenyl hexatriene (DPH), and of tryptophan), as well as by energy transfer from the tryptophan to the lipid probes, in ghosts prepared prior to or after application of pressure to intact RBC. The morphology of intact RBC, prior to or after application of pressure, was evaluated by scanning electron microscopy. It was found that (1) The FA of DPll, which resides in different apolar membrane regions, was increased as a function of the pressure applied and the duration of the treatment. At 15 atm the FA increased by 50%, reaching a plateau after 60 min of application of pressure. (2) Increased FA, to various extents, was observed also with the lipid probes which reside in the membrane lipid core, but not with probes which monitor the polar/apolar phospholipid interface, or the cell surface. (3) The same treatment increased tryptophan anisotropy by about 20%. (4) Tryptophan energy transfer to the lipid probes which resides in the lipid core was increased to various degrees which were related to the increase of the FA of these probes. (5) Following application of 15 atm for 1 hour, at least 60% of the RBC change their shape from discocytes to stomatocytes. These results demonstrate that hydrostatic pressure at physiological levels, might induce reduction of the membrane fluidity of RBC, which affects the physical state of protein environment, and might alter RBC morphology.
Studies of Photo-Induced Tunnel Currents in A1-A1203-Au Structures
(
Book
)
1 edition published in 1972 in English and held by 1 library worldwide The work describes the study of tunnel-diodes of the metal-insulator-metal structure based on measurements of the photo-induced tunnel current (PITC). Effort provided a series of measurements on Al-Al2O3-Au tunnel diodes that included PITC as well as I-V and internal photo-emission measurements. A simplified model is presented from which a theoretical expression for the PITC can be derived. It is shown that the experimental results are in a fairly good agreement with the theory. The potential barriers at the Al-Al2O3 and Au-Al2O3 interfaces were deduced to be 2.0 and 4.35 ev. The cross-section for photo-generation of electrons in the aluminum metal was estimated as 10 to the minus 16th power sq cm. It is also shown that electron reflection at the metal-oxide interfaces and/or scattering in the Al2O3 layer are quite important, possibly reducing the current by as much as two orders of magnitude. (Author).
A method for determination of the optical constants of thin absorbing layers
(
Book
)
1 edition published in 1963 in English and held by 1 library worldwide A method has been developed by which the optical constants of an absorbing layer on an absorbing base can be determined. The amplitude and phase of the light reflected by such a ststem is a known function of the parameters - complex refractive indices of film and substrate, film thickness and gngle of incidence. But the equations are intractible and cannot be solved for refractive index of the film. The use of a search technique for an electronic computer makes the reverse calculation possible. Given suitable starting values, one can determine rather quickly the film index giving rise to measured values of the intensity and phase difference of the reflected light. Application of this method to thin layers of nickel black shows that the layer is inhomogeneous. The consequences of inhomogeneity are discussed. Many of the values for the optical constants of thin films which have been reported by other workers are, in fact, average values for inhomogeneous layers. Such values have only limited significance in predicting the optical behaviour of inhomogeneous layers. (Author).
SYNTACTIC SIMPLIFICATION
(
Book
)
1 edition published in 1963 in English and held by 1 library worldwide The problem of syntactic complexity is investigated under the assumption that the complexity function is recursive (or at least partial recursive); this is surely the weakest restriction under which results of any significance may be expected. Various restrictions are imposed, also, upon the minimization procedures considered; these restrictions are at first quite strong and are then gradually weakened. The results are, for the most part, negative; it is proved that the possibilities of effective ''simplification'', in the above sense, are limited in the extreme. (Author).
THE THEORY OF TRANSFINITE EFFECTIVITY
(
Book
)
1 edition published in 1963 in English and held by 1 library worldwide
Complex function theory over non-archimedean fields
(
Book
)
1 edition published in 1962 in English and held by 1 library worldwide A satisfactory theory of complex functions is shown to exist over certain non-Archimedean fields. The theory is applie to the simplification and development of some branches of classical Function Theory. New results are obtained concerning the zeros of complex polynomials and on th behavior of an analytic function in the neighbor ood of an essential singularity. Mathematical Logic provides a basic part of the arguments. (Author).
Development of a Rapid and Sensitive Test for the Detection of Prions in Cultured Cells
(
Book
)
1 edition published in 2004 in English and held by 1 library worldwide This project endeavors to create cell culture systems for the sensitive and rapid detection of prions. We have proposed to achieve this task by improving steps and components involved (i) in the infection of cells with prions, (ii) in the amplification of prions by cells, and (iii) in the detection of infected cells, To achieve these aims, we are trying to: 1. Identify or create improved cell lines that are more susceptible to prion infection. 2. Improve the delivery of prions to cells by improving their presentation and method of administration, 3. Increase the level of prion/Prp(exp SC) amplification in the infected cells. 4. Design better ways to detect prion infection in cells, either by increasing the formation of PrP(exp SC) or by devising new, non-PrP(exp SC) surrogate' markers. more
fewer
Audience Level
|
Languages
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Related Identities