Showing papers by "Griffith University published in 1977"
TL;DR: The chapter highlights several aspects of the subject that would appear to be worthy of greater attention—the realities of enzyme and metabolite concentrations in tissues, the feasibility of reversible reactions contributing to control, the concept of sandwiching of regulatory metabolites between controlled enzymes, and the importance of interactions between macro- and micromolecular components.
Abstract: Publisher Summary The concepts of feedback regulation have dominated considerations of metabolic control in cells and tissues in recent years and have markedly advanced our ability to comprehend the nature of self-regulation and the strategic positioning and complex interrelationships of regulatory systems This marriage of in vitro attributes of control enzymes with in vivo potentialities for regulation is deserving of its frequent nomination as a triumphant example of the analytical approach in biology The chapter highlights several aspects of the subject that would appear to be worthy of greater attention in this regard—the realities of enzyme and metabolite concentrations in tissues, the feasibility of reversible reactions contributing to control, the concept of sandwiching of regulatory metabolites between controlled enzymes, and the importance of interactions between macro- and micromolecular components
79 citations
TL;DR: An overview of trends in workplace health promotion shows that current thinking has changed from a narrowly based risk–factors approach aimed at individual behaviour changes, to an integrative approach aimed for creating health–promoting workplaces.
77 citations
TL;DR: The binding constants for related amides and methyl ketones confirm that it is principally the lower steric requirement of the aldehyde rather than its increased electrophilicity which is responsible for its powerful inhibitor properties.
Abstract: N-Acyl-aminoacetaldehydes are potent inhibitors of the proteolytic enzyme, papain. Although they exist predominantly in their hydrated form in aqueous solution only the aldehyde is an effective inhibitor. The binding constants for related amides and methyl ketones confirm that it is principally the lower steric requirement of the aldehyde rather than its increased electrophilicity which is responsible for its powerful inhibitor properties. Using nuclear magnetic resonance spectroscopy, evidence is provided for an N-acetyl-aminoacetaldehyde-papain complex. Using a cross-saturation technique evidence is also provided for a hemithioacetal, formed from the aldehyde and the active-site thiol group. Hemithioacetal formation has also been detected between N-benzoyl-aminoacetaldehyde and papain. This provides the first direct evidence for a tetrahedral adduct with papain and supports the proposed involvement of such intermediates in papain-catalysed hydrolyses.
46 citations
TL;DR: Electrophoretic polymorphisms for stomach alcohol dehydrogenase (ADH-C2) and kidney L-alpha-hydroxyacid oxidase (HAOX-B4) have been identified in an Asian subspecies of mouse, Musmusculus castaneous.
Abstract: Electrophoretic polymorphisms for stomach alcohol dehydrogenase (ADH-C2) and kidney L-α-hydroxyacid oxidase (HAOX-B 4) have been identified in an Asian subspecies of mouse, Mus musculus castaneous. These variants are inherited in a normal Mendelian fashion with two alleles in each case showing codominant expression. The structural gene loci for those enzymes (Adh-3 and Hao-2, respectively) are apparently linked (17.6% recombinants) in this organism, whereas the multiple gene loci for HAOX, Hao-1 (encoding the A4 liver isozyme) and Hao-2, exhibited independent segregation and are unlinked (50% recombinants). Evidence is presented for 3 ADH loci: Adh-1, encoding liver ADH-A2 which exhibits high activity with ethanol (Selander, Hunt and Yang 1969; Adh-2, liver and stomach ADH-B 2 using 2-hexene-1-ol as substrate; and Adh-3, stomach ADH-C 2 using both benzyl alcohol and 2-hexene-1-ol as substrate.
33 citations
TL;DR: Using discrete mixtures of seeds it was found that ants from colonies in both sown and native pastures would preferentially remove seed of the native grass species, Themeda australis and Digitaria ciliaris, to the introduced legume Stylosanthes humilis.
Abstract: Seed harvesting ants (mainly Pheidole spp.) in the Katherine area of the Northern Territory have been observed to actively forage seed in both native and sown pasture areas. Using discrete mixtures of seeds it was found that ants from colonies in both sown and native pastures would preferentially remove seed of the native grass species, Themeda australis and Digitaria ciliaris, to the introduced legume Stylosanthes humilis. This difference in selection could not be explained solely on a basis of size or weight differences between the species.
The preference for grass species over introduced legumes indicates that ant predation is not the main factor in the low seed survival to germination in introduced pastures.
33 citations
TL;DR: In this article, a stochastic model for man-caused forest fires is developed for a forest with given environmental conditions which is represented by an index, and the mean and the variance of the number of fires is derived.
23 citations
TL;DR: In this article, the carbonic anhydrase (CA) isozyme was found to be predominantly localized in red skeletal muscles, although this activity was also observed in white and mixed skeletal muscles of the cat, sheep and rabbit, as well as sheep lung and rabbit liver.
Abstract: 1. 1. Starch gel electrophoretic patterns of carbonic anhydrase (CA) isozymes were examined from tissue extracts of cats, sheep, rabbits and mice. 2. 2. In addition to the widely distributed and extensively studied B and C isozymes, an additional isozyme (called CA-A) was observed. 3. 3. Tissue distribution studies showed the A isozyme to be predominantly localized in red skeletal muscles, although this activity was also observed in white and “mixed” skeletal muscles of the cat, sheep and rabbit, as well as sheep lung and rabbit liver. 4. 4. A, B and C isozymes of carbonic anhydrase from cat, sheep and mice exhibited independent variations in nett surface charge. In terms of decreasing anodal migration, the following results are reported: cat A > C > B; sheep C > B > A; and mouse B > C > A. 5. 5. These results are consistent with the existence of 3 genetic loci encoding carbonic anhydrase in mammalian tissues.
18 citations
18 citations
TL;DR: The variable temperature carbon-13 and mercury-199 nmr spectra of some cyclohexylmercurials have been recorded and assigned by consideration of chemical shifts, 199 Hg- 13 C coupling constants and comparisons with the data for 4-methylcyclohexymethyl derivatives of established constitution as mentioned in this paper.
17 citations
TL;DR: In this article, the natural abundance 13 C NMR spectra of a number of oxythallation adducts of norbornenes have been obtained and assigned by considerations of SFORD spectra, chemical shifts, comparisons of spectra at different frequencies, T 1 values and some aspects of 203,205 Tl 13 C couplings.
14 citations
TL;DR: In this paper, the natural abundance 13C n.m. spectra of a series of para-substituted ethylbenzenes and Cipso in the phenyl series were examined at low dilution in deuterochloroform solvent.
Abstract: The natural abundance 13C n.m.r. spectra of a series of para-substituted ethylbenzenes, 4-substituted-1-ethylnaphthalenes and a limited series of 6-substituted-2-ethylnaphthalenes have been examined at low dilution in deuterochloroform solvent. The ethyl carbons and Cipso in the phenyl series (i.e. have been assigned, and substituent chemical shifts for these carbons calculated and analysed by the Dual Substituent Parameter treatment. (Chemical shifts of all ring carbons have been obtained, but not assigned). Generally speaking, electron-withdrawing substituents lead to positive (i.e. downfield) substituent chemical shifts for CH2 and negative substituent chemical shifts for CH3, i.e. ‘normal’ and ‘inverse’ behaviour respectively. Cipso in the phenyl series exhibits a ‘normal’ dependence. The dependences of the various substituent chemical shifts on inductive and resonance parameters are discussed, and compared with the behaviour of side chain carbons in other substituted benzene systems.
TL;DR: Signs are provided that appreciable degradation may occur during embryogenesis, with general proteolysis proceeding at a faster rate than with lactate dehydrogenase, and with higher rates of degradation occurring in foetuses which were smaller than average.
TL;DR: In this paper, the electron-photon coincidence experiments on helium excitation have been used together with differential cross section data to determine line polarisations independently of previous direct measurements, and reasonable agreement is found with data from a recent experiment on the vacuum ultraviolet line polarisation of helium and with one experimental on the 501.6 nm line.
Abstract: Data obtained in recent electron-photon coincidence experiments on helium excitation have been used together with differential cross section data to determine line polarisations independently of previous direct measurements. Polarisations have been determined at electron impact energies in the range 60-100 eV for the following lines: 21P-11S (58.4 nm), 31P-11S (53.7 nm) and 31P-21S (501.6 nm). Reasonable agreement is found with data from a recent experiment on the vacuum ultraviolet line polarisation of helium and with one experiment on the 501.6 nm line. The data are compared with recent theoretical predictions.
TL;DR: In this article, some of the classical concepts of control require reexamination in the light of the realities of the microenvironment, and some of these concepts need to be re-examined.
TL;DR: Optimal immunization policies together with corresponding optimal costs are presented for the Greenwood and Reed-Frost chain-binomial epidemic models.
Abstract: A policy of immunization is considered for the Greenwood and Reed-Frost chain-binomial epidemic models. In the case of the Reed-Frost model the assumption is made that the probability of contact between two individuals is either small or large. The principle of optimality is used to derive dynamic programming equations for both deterministic and stochastic versions of these models. Optimal immunization policies together with corresponding optimal costs are presented.
TL;DR: In this paper, new experimental results for Stage I and III recovery in electron-irradiated Zn are presented, and several recovery models are investigated; the totality of available results cannot readily be explained fully by either of the two currently most widely accepted models.
Abstract: Some new experimental results for Stage I and III recovery in electron-irradiated Zn are presented. Stage I ( 70 K) exhibits several features different from those reported previously. In particular, a sub-stage centered at 140 K, thought to be dose-dependent, exhibits no observable shift. A possible explanation is suggested. Several recovery models are investigated; the totality of available results cannot readily be explained fully by either of the two currently most widelyaccepted models.
Es werden neue experimentelle Ergebnisse fur Erholung der Stufen I und III in elektronenbestrahltem Zn mitgeteilt. Es wird gefunden, das Stufe I ( 70 K) zeigt einige Merkmale, die von den fruher berichteten unterschiedlich sind. Insbesondere zeigt ein bei 140 K gelegener Subzustand, von dem angenommen wird, das er dosisabhangig ist, keine beobachtbare Verschiebung. Eine mogliche Erklarung wird vorgeschlagen. Einige Erholungsmodelle werden untersucht. Die Gesamtheit der vorhandenen Ergebnisse last sich von keinem der beiden zur Zeit am verbreitetsten akzeptierten Modelle vollstandig erklaren.
TL;DR: The double exponential rate equation for dislocation motion developed by Nichols is examined in this paper and it is shown that for the usual case where the back activation area is greater than the forward activation area, a plot of dislocation velocity versus effective stress, τ, exhibits an inflexion point at intermediate levels of effective stress.
Abstract: The double exponential rate equation for dislocation motion developed by Nichols is examined. It is shown that for the usual case where the back activation area is greater than the forward activation area, a plot of dislocation velocity versus effective stress, τ, exhibits an inflexion point at intermediate levels of effective stress. In this case the stress sensitivity of dislocation velocity, n, is shown to assume values of less than unity near the inflexion point. At lower τ levels n approaches unity and decreases with increasing τ while at higher values of τ, n increases in a manner characteristic of a single exponential function. Since this behaviour is at variance with experimental evidence it is concluded that the basic assumptions required in the application of the equation to experimental results are possibly invalid.
TL;DR: Subcellular fractionation of liver slices after incubation with 18F showed that, regardless of the incubation time and method of washing, at least half of the radioactivity was in the cell sap, but that there was some preferential retention of 18F by the mitochondria.
TL;DR: In these experiments lactate dehydrogenase was isolated from the tissues by means of affinity chromatography and consequently the procedure has enabled not only an extension of previously available turnover data, but also, by comparison with the available data from immunologically based methodologies, an assessment of the relative contributions of antigenic and enzymic sites to turnover parameters.
TL;DR: The selfconsistent Einstein model is suggested as a good starting point for the Koehler self-consistent phonon iterative scheme, with the advantage that no costly numerical Brillouin zone integrations are required as mentioned in this paper.
01 Jan 1977