Showing papers by "La Trobe University published in 1978"

ENZYMATIC DETERMINATION OF 1,3:1,4-β-GLUCANS IN BARLEY GRAIN AND OTHER CEREALS†

Abstract: A direct and specific enzymatic method is described for the determination of 1,3:1,4-β-glucans in barley grain and other cereals. In the procedure, purified, amylase-free, bacterial 1,3:1,4-β-glucan hydrolase is used to depolymerize the 1,3:1,4-β-glucan in autoclaved and ethanol-extracted flour prepared from whole grain. The liberated oligoglucosides are extracted with 80% (vol/vol) ethanol and, following acid hydrolysis, measured by the glucose oxidase method. The method can be used to measure total β-glucan and β-glucan in 65°C water-soluble and water-insoluble fractions of cereal grains. The procedure has been applied to barley grains allowed to develop under controlled environmental conditions and to a series of barleys of different geographical origins. The results for Canadian cultivars are compared with estimates based on viscometric data for the same samples. The 1,3:1,4-β-glucan content of a number of other cereals has also been measured.

The use of habitat components by small mammals in eastern Australia

Abstract: The effect of habitat components (vegetation density at two levels, litter, logs and roads) on the distribution of small mammals was assessed in adjacent areas of native forest and Pinus taeda plantation in north-eastern New South Wales. Rattus fuscipes was associated with structural complexity in native forest but not in pine plantation where it was found on downslope areas. R. rattus was associated with windrows in the pine plantation, R. lutreolus with areas devoid of a shrub layer in the pine plantation, Antechinus stuartii with logs and Melomys cervinipes with habitat components associated with rainforest areas. Road crossing by small mammals was inversely related to road width; roads severely restricted or stopped the movement of small mammals even when the road consisted of a long-unused and partly overgrown track.

The specific interaction of cibacron and related dyes with cyclic nucleotide phosphodiesterase and lactate dehydrogenase.

Abstract: 1. Reactive Blue 2 (Cibacron Blue 3G-A) is a competitive inhibitor of bovine heart cyclic nucleotide phosphodiesterase (Ki 0.3μm). The Ki increases with increasing temperature, suggesting that hydrophobic interactions are not largely responsible for the binding of the dye. Another 25 sulphonated aromatic dyes are also competitive inhibitors of the cyclic nucleotide phosphodiesterase (Ki values in the range of 0.06–13.6μm). 2. These dyes (covalently linked to Dextran 40) inhibit bovine heart cyclic nucleotide phosphodiesterase. Reactive Blue 2 (covalently linked to Dextran 40) is a competitive inhibitor of the phosphodiesterase (Ki 0.4μm). 3. Bovine heart cyclic nucleotide phosphodiesterase is retained on a column of Reactive Blue 2-Sephacryl S-200 and can be eluted from the column by 3′:5′-cyclic AMP. 4. A variety of the dyes (either free or covalently linked to Dextran 40) are competitive inhibitors of rabbit muscle lactate dehydrogenase. 5. The effectiveness of a wide range of structurally dissimilar dyes as competitive inhibitors of lactate dehydrogenase and cyclic nucleotide phosphodiesterase compromises proposals for the use of Reactive Blue 2 as a specific probe for the dinucleotide-binding structural domain present in many dehydrogenases and kinases. Detailed information of the various dyes used has been deposited as Supplementary Publication SUP 50089 (7 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

The steady-state kinetics of yeast phosphoglycerate kinase. Anomalous kinetic plots and the effects of salts on activity.

Abstract: 1 A re-investigation of the kinetics of yeast phosphoglycerate kinase in the direction of 1,3-bis-phosphoglycerate formation has been carried out, covering a 1000-fold range in substrate concentrations. A variety of improved spectrophotometric and fluorimetric assay procedures have been used. 2 Kinetic plots proved to be non-linear for each variable substrate. A variety of checks have been carried out to show that this is not due to artifacts in the assay procedures or heterogeneity of the enzyme preparation. 3 The effects of a variety of salts on the activity of the enzyme have been examined. Most salts, especially those with multivalent anions, can cause activation of the enzyme, but inhibit at high concentration. 4 The salt effect is shown to be principally due to anions rather than cations, and not to ionic strength changes. Sulphate, as one of the most effective anions has been used in most comparisons. 5 Salt activation is steepest when the substrate concentrations are low; maximum activation has been about 5-fold with 0.2 mM MgATP and 0.2 mM 3-phosphoglycerate. Inhibition at the higher salt concentrations is strongest at the same substrate concentrations as when activation is steepest, indicating a link between the two effects. 6 The presence of 20 mM or more Na2SO4 converted non-linear kinetic plots to linear ones. A study of the kinetics in the presence of 40 mM Na2SO4 was interpreted in terms of a random sequential binding mechanism, with sulphate acting as a competitive inhibitor. 7 Possible explanations for these anomalous results are discussed in terms of several mechanisms which have been shown to apply in other systems.

The Moruya Batholith and geochemical contrasts between the Moruya and Jindabyne suites

Abstract: Rocks of the Moruya Batholith range from gabbros and gabbroic diorites through quartz diorites and tonalites to granodiorites and rare adamellites The gabbros and gabbroic diorites appear as small, early bodies intruded and enclosed by quartz diorites and tonalites These early gabbroids are petrographically and chemically distinct from the granitoids The latter occur as a meridionally‐oriented sequence of nine separate plutons Mafic xenoliths are most abundant in the quartz diorites and tonalites; they are petrographically similar to their host granitoids and are chemically a more mafic extension of the variation in granitoid compositions The various granitoid bodies are considered to be derived from similar source rocks, with the xenoliths representing modified material relict from partial melting of that source Comparison of chemical data from the Moruya granitoids with those of the I‐types of the Jindabyne Suite in the Kosciusko Batholith, shows that the potassium content is indistinguis

Light-dependent Reduction of Oxidized Glutathione by Ruptured Chloroplasts

Abstract: Crude extracts of pea shoots ( Pisum sativum ) catalyzed oxidized glutathione (GSSG)-dependent oxidation of NADPH which was attributed to NADPH-specific glutathione reductase. The pH optimum was 8 and the K m values for GSSG and NADPH were 23 μm and 4.9 μm, respectively. Reduced glutathione (GSH) inhibited the reaction. Crude extracts also catalyzed NADPH-dependent reduction of GSSG; the ratio of the rate of NADPH oxidized to GSH formed was 0.49. NADH and various substituted mono- and disulfides would not substitute for NADPH and GSSG respectively. Per mg of chlorophyll, enzyme activity of isolated chloroplasts was 69% of the activity of crude extracts. Illuminated sonicated pea chloroplasts, in the presence of catalytic amounts of NADPH, catalyzed GSSG-dependent O 2 evolution (mean of 10 determinations, 10.4 μmol per mg chlorophyll per hour, sd 1.4) with the concomitant production of GSH. The molar ratio of GSH produced to O 2 evolved was 3.8 and the highest ratios for O 2 evolved to GSSG added were 0.46 and 0.44. The K m value for GSSG was 26 μm. GSH inhibited the reaction. The reaction was attributed to photosynthetically coupled glutathione reductase. Ruptured chloroplasts, in the presence of catalytic amounts of GSSG and NADPH, did not catalyze sustained O 2 evolution in the presence of substrate amounts of hydrogen peroxide, dehydroascorbate, l-cystine, sulfite, or sulfate.

Binding of substrates and other anions to yeast phosphoglycerate kinase.

Abstract: 1 The binding of all four substrates to yeast phosphoglycerate kinase has been studied using a gel filtration technique. The binding of phosphate and sulphate anions has also been investigated. 2 Two sites for each adenine nucleotide were found, one site being weaker than the other by between 30 and 50-fold. Only one binding site for the phosphoglycerate substrates was found. 3 1,3-Bisphosphoglycerate (1,3-P2-glycerate) bound to the enzyme approximately 1000 times tighter than the other three substrates, its dissociation constant being 0.06 μM at ionic strength 0.15 M. 4 Sulphate and phosphate were mutually competitive and sulphate competed with the binding of all substrates except MgADP. MgADP bound to the enzyme more weakly in the presence of sulphate. The dissociation constant for sulphate binding was 1.6 mM at ionic strength of 0.15 M, and 0.05 mM at ionic strength 0.015 M. 5 These results are consistent with sulphate acting as a competitive inhibitor, as found by kinetic studies at high sulphate concentrations. The activatory effect of sulphate at lower concentrations and the substrate activation phenomena displayed by this enzyme, are interpreted in terms of a two-step dissociation of 1,3-P2-glycerate. The presence of moderate concentrations of MgATP, 3-phosphoglycerate or sulphate causes acceleration of the rate of dissociation of the product, 1,3-P2-glycerate, this being the rate-limiting step in the overall enzyme reaction.

Naturally-occurring heavy metal binding proteins in invertebrates

Abstract: Low molecular weight cadmium, copper, and zinc binding protein has been isolated from the musselMytilus edulis in the cadmium polluted areas of Corio Bay adjacent to Melbourne. Its molecular weight and other properties suggest that it belongs to the metallothionein family of metal binding proteins. Its synthesis may have been induced in the cyctoplasmic solutions of the cells as a regulatory mechanism to avoid intoxication by excess uptake of any of the metals.

Quaternization of Heteroaromatic Compounds: Quantitative Aspects

Abstract: Publisher Summary This chapter focuses on important developments dealing with quaternization of annular nitrogen atoms of heterocyclic compounds The chapter is essentially divided into two main parts The first part describes the main electronic and steric factors of heteroaromatic nucleophilic reactants that influence their reactivity The second part provides references to recent important developments The chapter considers six-membered heteroaromatic rings before five-membered ones as the six-membered rings are studied in greater detail and consequently their reactions are better understood The chapter notes that quaternization of an annular nitrogen atom is carried out with a wide range of alkylating agents Most quaternization reactions involving an annular nitrogen atom and an alkylating agent proceed by way of an S N 2 reaction in which the inversion of configuration of a chiral reagent takes place One novel method, which indicates that the transition state is early, involves the study of volume changes Many approaches are made to obtain information about the nature of the transition state of quaternization reactions, including a study of kinetic isotope effects

Schedule induced self-injection of d-amphetamine by naive animals

Abstract: Naive rats were initially allowed to self-inject 0.05, 0.2 or 0.8 mg/kg infusion of d-amphetamine under conditions of 100% body weight and 80% reduced body weight with or without a fixed time-1 min (FT-1) food delivery schedule. In a further experiment using 0.05 mg/kg amphetamine the self-injection rates of animals under 100% and 80% body weight were compared with rates of animals at 90% body weight with or without FT-1 schedule conditions. The results showed that (a) when body weight is reduced to 80% animals without an FT-1 food delivery schedule self-inject at a higher rate than those on the FT-1 schedule, which is contrary to self-injection patterns found for nicotine, methadone and heroin, (b) the lowest dose of 0.05 mg/kg produced the highest self-injection rate in all conditions, and (c) the highest level of food deprivation (80% body weight) is more effective than normal and 90% body weight in producing amphetamine self-injection. These findinfs indicate that to initiate high levels of amphetamine self-injection an interaction of food deprivation state and the pharmacological property of the drug is a critical variable.

Stimulation of volume flow and ion flux by abscisic acid in excised root systems of Phaseolus vulgaris L. cv. Redland Pioneer.

Abstract: Abscisic acid (ABA) caused a 7–8-fold increase in volume flow in excised bean root systems and this was coupled with an increase in 42K, 36Cl and 24Na flux into the xylem. The transport of 42K and 36Cl increased by a factor larger than the stimulation of volume flow, resulting in an increase in the concentration of those ions in the xylem exudate. Carbonyclcyanide-m-chlorophenyl hydrazone, on the other hand, eliminated ABA-stimulated 42K transport and caused a further inhibition of 42K flux, thus providing additional support for the proposition that ABA stimulation may involve an energised process of ion transport. ABA also increased the accumulation of 24Na and 36Cl in bean root tissue, but not that of 42K.

Properties of a high-affinity cytokinin-binding protein from wheat germ.

Abstract: A soluble protein that interacts with a range of cytokinins was extensively purified from wheat (Triticum aestivum L.) germ. This protein has a K d for kinetin of 2×10-7 M. The binding of kinetin to the protein is inhibited by low concentrations of synthetic and naturally-occurring cytokinins including N6-benzyladenine, N6-benzyladenosine, kinetin riboside, N6-dimethylallyladenine, N6-dimethylallyladenosine, zeatin, zeatin riboside, N6-dimethyladenine and N6-dimethyladenosine. Adenine, adenosine and several non-N6-substituted adenine derivatives were ineffective as inhibitors of kinetin binding. While N6-butyryl-3′,5′-cyclic AMP, N6,2-O′-dibutyryl-3′,5′-cyclic AMP and 2′,3′-cyclic AMP inhibited binding of kinetin to the protein, 3′,5′-cyclic AMP was ineffective. The kinetin-binding protein is heat-labile and pronase-sensitive. Kinetin-binding activity exactly co-chromatographs with a single peak of carbohydrate and protein on gel-filtration and is displaced from concanavalin A-Sepharose 4B by α-methylglucoside. On gel filtration, the kinetin-binding protein behaves as a soluble protein with an apparent molecular weight of 180,000 daltons.

Multiple independent control mechanisms affecting the acetamidase of Aspergillus nidulans.

Abstract: The acetamidase of Aspergillus nidulans is induced by sources of acetyl CoA, benzoate and benzamide and by beta-alanine and other omega-amino acids. The effects of these groups of inducers are appromimately additive. The cis-acting control site mutant, amdI9, affects induction by sources of acetyl-CoA specifically. Lesions in the amdR and gatA genes affect induction by omega-amino acids specifically. Mutations in the amdA gene can lead to elevated acetamidase levels which still respond to the various inducers. The induction controls act independently of repression control by nitrogen metabolites and are not altered by the areA102 mutation. The properties of double mutants with lesions affecting the different control mechanisms also indicate their independence of each other. It is suggested that the acetamidase is subject to complex control by multiple regulatory circuits and that functionally independent control sites adjacent to the structural gene occur.

Schedule induced self injections of nicotine with recovered body weight.

Abstract: In a recent series of experiments we have shown that high rates of self injection of nicotine were acquired when rats are at 80% body weight on an FT-1 min food delivery schedule. This rate was significantly higher than that of rats at reduced or normal body weight without food delivery schedules or that of rats injecting saline under three parallel control conditions. In the present experiment naive rats were trained to acquire nicotine self injection at 80% body weight with an FT-1 min food delivery schedule. These rats maintained their self injection rates after they were allowed to regain free feeding body weight. The data indicate that once nicotine intake behavior is established it can be maintained with changing nutritional factors.

The relationship of reliability in classroom research to the amount of observation: an extension of the spearman-brown formula

Abstract: Direct observation of teachers teaching and of learners learning has come to be regarded in recent years as an important element of research aimed at improving our understanding of the teaching-learning process. Of this research, a large part has been essentially quantitative, as evidenced by a quick glance through a review such as that by Rosenshine (1971), in which 51 essentially correlational studies are reported. Aside from the generally inconclusive nature of most of the research reviewed,' one's attention is drawn immediately to the lack of impact which measurement theory has had upon the practice of classroom observation. It is clear that a good deal of measurement necessarily takes place when teachers and pupils are observed, whether it be in counting the frequency of occurrence of particular behaviors, measuring the time devoted to particular activities, or computing the nowfamiliar indirect/direct ratio (Flanders, 1970). Yet only recently (Cronbach, Gleser, Nanda, & Rajaratnam, 1972; McGaw, Wardrop, & Bunda, 1972; Medley & Mitzel, 1963) has classroom observation attracted the attention of measurement specialists. Consequently, greater interest has developed in the measurement properties of observational measures (e.g., Shavelson & Dempsey-Atwood, 1976). Measurement theory, by and large, has been developed in the context of paperand-pencil tests of mental abilities and psychological constructs, and many of its concepts and assumptions reflect this origin (e.g., true score, item discrimination, item characteristic curve). The measurement of classroom behavior is an area to which the relevance of many of these concepts and assumptions is not obvious. There is, however, a sense in which the responses of a student to a test and a record of a person's observed behavior are logically equivalent. Each records a sample of behavior. In many cases, the same kind of information is recorded: the frequency of occurrence of a particular behavior of interest (in the case of the test, the behavior of interest is the giving of a correct response to an item). Test scores are not fundamentally different from behavioral measurements, but they are more properly seen as a particular kind of behavioral measurement in which the conditions of measure-

Models and designs for experiments with mixtures

Abstract: Summary Properties such as the tensile strength of an alloy of. different metals and the freezing point of a mixture of liquid chemicals, depend on the proportions (by weight or volume) of the components present and not on the total amount of the mixture. In choosing a model to relate such a property to the proportions of the various components of the mixture, there arise intriguing difficulties due to the fact that proportions sum to unity. It is demonstrated how to construct models which allow for the possibility of inactive components (components that do not affect the property at all) or components with additive effects. The design of experiments to fit such models to data is then discussed with a view to determining whether a given component is inactive or has an additive effect. The optimal allocation of observations to simplex-lattice designs is considered for one of these models. The construction of D -optimal designs for these models is an open problem.

Education and Change in American Opinions on a Woman for President

Abstract: During the early 1970s, the increase in willingness of Americans to vote for a woman for president was directly related to education and contrasts with the inverse relationshipbetween education and increasesinwillingness to vote for ablackforpresident. The contrast indicates that on some issues, the relationship between education and "enlightened" opinions is variable and characterizes mainly the middle stages of such issues' life histories. E. M. Schreiber is Senior Lecturer in Sociology at La Trobe University in Melbourne, Australia. Public Opinion Quarterly ?) 1978 by The Trustees of Columbia University Published by Elsevier North-Holland, Inc. 0033-362X/78/0042-0171/$1.75 This content downloaded from 157.55.39.207 on Thu, 20 Oct 2016 04:08:01 UTC All use subject to http://about.jstor.org/terms

The thermal biology of Geolycosa godeffroyi and other burrow inhabiting Lycosidae (Araneae) in Australia

Abstract: Using both field and laboratory data a detailed examination of behavioural thermoregulation is presented for Geolycosa godeffroyi (Koch), a burrow inhabiting Australian wolf spider; comparative data are given for Schizocosa leuckartii (Thorell), Venatrix fuscus (Hogg), Lycosa speciosa Koch, and two undescribed species of Lycosa. Egg sac and spider body temperatures were recorded either by implanted thermocouples or biotelemetry. The burrows permitted the spiders access to a wide range of temperature throughout the day but the spiders maintained temperatures above the upper limit of this range except in the middle of the day in summer. In winter the burrows protected the spiders from extreme cold. G. godeffroyi thermoregulated throughout the year and could achieve temperatures of 38°C when the global radiation exceeded about 260 mW cm-2 d-1. The activity regimes deduced from temperature recording were in accord with those derived using field actographs and photographic recording. The spiders thermoregulated in a manner similar to that used by behaviourally thermoregulating lizards and did so whenever conditions were suitable. They maintained temperatures between 32 and 36°C but the preferred temperature was reduced by lack of food or water, in egg sacs or females carrying egg sacs and in mature males to about 30°C. The data do not support the concept of a refractory zone but suggest two or more set points required for specific physiological or ecological purposes.