Showing papers by "University of Adelaide published in 1973"
498 citations
TL;DR: Berries on field-grown Vitis vinifera cv.
Abstract: Berries on field-grown Vitis vinifera cv. Doradillo were treated at different times during stage II with benzothiazole-2-oxyacetic acid or 2-chloroethylphosphonic acid, and measurements were made of their growth and hormone content. The concentration of ethylene was low during stage II and declined as berries ripened. Both 2-chloroethylphosphonic acid and benzothiazole-2-oxyacetic acid caused increases in ethylene concentration, yet they had varying effects on ripening: the former applied at the start of stage II and the latter applied 1 week before the end of stage II delayed ripening, while 2-chloroethylphosphonic acid applied at the end of stage II hastened ripening.The abscisic acid content of berries increased as they ripened, and the effects of 2-chloroethylphosphonic acid and benzothiazole-2-oxyacetic acid on abscisic acid levels were correlated with the effect of these compounds on ripening. The roles of abscisic acid and ethylene in the regulation of the ripening of grapes are discussed.
297 citations
TL;DR: The variation of infectivity with the concentration ofCMV and of CMV RNA has shown single hit kinetics even though lesion formation probably requires the initial simultaneous infection of each cell by the three largest RNA species.
237 citations
TL;DR: A new method involving the use of combined endodontic-orthodontics treatment to allow treatment of transverse root fractures near the gingival crevice appears to provide a solution to an otherwise difficult clinical problem.
198 citations
TL;DR: A model is proposed which ties together three previously existing models current in this field: the Inverted-U Hypothesis, Signal Detection Theory and the Yerkes-Dodson Law and is examined further in relation to individual differences of personality and to problems of conserving talent among students and those carrying heavy executive responsibility.
Abstract: The effects on performance are discussed of various types of stress deriving from imbalance between capacity on the one hand and, on the other, the demands of tasks, environmental conditions and social situations which either overload or underload the individual. Common cybernetic principles seem to apply over an area which includes not only stress, but also motivation and arousal. A model is proposed which ties together three previously existing models current in this field: the Inverted-U Hypothesis, Signal Detection Theory and the Yerkes-Dodson Law. The model is examined further in relation to individual differences of personality and to problems of conserving talent among students and those carrying heavy executive responsibility.
195 citations
TL;DR: The microstructural transition from amphibolite facies, gneissic country rock, with increasing deformation, to a fine-grained phyllitic mylonite is described in detail in this paper.
193 citations
133 citations
TL;DR: It was found that different isolates of Tulasnella calospora differed markedly in the efficiency with which they stimulated germination of the species of Diuris and Thelymitra and the most efficient isolates were not necessarily those isolated from these orchids.
Abstract: SUMMARY
In symbiosis tests on an agar medium with powdered cellulose as carbon source, isolates of several species of Tulasnella and of Ceratobasidium cornigerum were compared on seven species of Thelymitra and two each of Diuris and Pterostylis. The Pterostylis species were stimulated to germinate only by Ceratobasidium cornigerum, the Diuris species only by Tulasnella calospora but, in general, the Thelymitra species were stimulated by more than one species of Tulasnella, but not markedly by Ceratobasidium cornigerum. These results correlate well with specificities noted in isolations from the roots of mature orchids of these genera in nature.
It was found that different isolates of Tulasnella calospora differed markedly in the efficiency with which they stimulated germination of the species of Diuris and Thelymitra. The most efficient isolates were not necessarily those isolated from these orchids.
116 citations
TL;DR: The results suggest that a variety of phytases are present in biological systems and that the initial point of dephosphorylation of phytic acid may occur at the l-i, d -4, 2 or 5 positions of the myo-inositol ring.
102 citations
TL;DR: In this article, the authors investigated the role of organic anions in controlling the influx of NO3- and Cl- into bailey roots, and concluded that organic anion can also play an important part in controlling influx of both NO3 and Cl.
Abstract: Summary
Measurements of net NO3- influx have been made with excised bailey roots of differing salt status. With roots grown in 0.2 mM CaSO4, net NO3- influx shows partial saturation with external NO3- concentrations greater than 0.5 mM, and is greatly reduced in the absence of external K+ or Na+. Net NO3- influx from NaNO3 solution is as rapid as from KNO3 solution, but when both K+ and Na+ are present the roots show high specificity for K+ over Na+. When roots are high in Cl-, net NO3- influx is greatly reduced, and the reciprocal effect of reduction in Cl- influx into roots high in NO3- is also found. There is some decrease in net NO3- influx and in Cl- influx when roots are high in organic anions, and under these conditions net NO3- influx is completely independent of cation influx. There is no effect of external Cl- (up to 10 mM) on net NO3- influx (1 mM solution), and very little or no effect of external NO3- on Cl- influx. The results are considered in relation to the hypothesis that influx of NO3- and Cl- is subject to feedback control from the internal NO3- plus Cl- content, but it is concluded that organic anions can also play an important part in controlling influx of NO3- and Cl-. The interactions between cation and anion fluxes are discussed, and a unifying model for ion transport proposed.
96 citations
TL;DR: The suggestion is made that the effect of the activation projected from such systems on the sets of cells involved in sequences of neural activity patterns which subserve ‘ mental functions ’ would depend upon the intensity of theactivation.
Abstract: A review is presented of literature regarding the physiological mechanisms which might relate to the arousal effects of exercise demonstrated by Davey's paper in this symposium. It is assumed that exercise is associated with raised activity in one of the diffusely-projecting neural systems, the ‘ Reticular Formation ’. It is suggested that the greater activity in this system could arise, on the one hand, as a part of the central programme initiating the muscular activation and associated cardiovascular excitation; and on the other, as a result of afferent feed-back from these peripheral changes. The suggestion is made that the effect of the activation projected from such systems on the sets of cells involved in sequences of neural activity patterns which subserve ‘ mental functions ’ would depend upon the intensity of the activation. If it is low, the level of excitation in the relevant target cells may be insufficient to ensure the correct sequential flow of the patterns. If it is high, the level of exci...
TL;DR: The idea that the British Isles were once separated by an ocean (the proto-Atlantic Ocean) which has since been destroyed by a continental drifting process was first proposed by Wilson as discussed by the authors.
Abstract: WILSON1 postulated, using faunal, tectonic and stratigraphic evidence, that the northern and southern parts of the British Isles were once separated by an ocean (the proto-Atlantic Ocean) which has since been destroyed by a continental drifting process in which the British Isles resulted from the welding together of land masses originally on different sides of the ocean. Following the stimulus of Wilson's idea and the possibility of plate tectonic theory providing an explanation for the continental movements, the geology of the central British Isles has been reappraised2–7 and the igneous, structural and stratigraphic features of the area have been related to the motion of lithospheric plates being thrust under continental masses as the continents converged.
TL;DR: The nitrate reductase in the mature root extract of 3-day maize (Zea mays) seedlings was relatively labile in vitro and the inactivating factor, which has a Q(10) 15 to 25 C of 2.2, was heat labile, and hence has been designated as a nitrate reducing enzyme inactivates enzyme.
Abstract: The nitrate reductase in the mature root extract of 3-day maize (Zea mays) seedlings was relatively labile in vitro. Insoluble polyvinylpyrrolidone used in the extraction medium produced only a slight increase in the stability of the enzyme. Mixing the mature root extract with that of the root tip promoted the inactivation of nitrate reductase in the latter. The inactivating factor in the mature root was separated from nitrate reductase by (NH(4))(2)SO(4) precipitation. Nitrate reductase was found in the 40% (NH(4))(2)SO(4) precipitate, while the inactivating factor was largely precipitated by 40 to 55% (NH(4))(2)SO(4). The latter fraction of the mature root inactivated the nitrate reductase isolated from the root tip, mature root, and scutellum. The inactivating factor, which has a Q(10) 15 to 25 C of 2.2, was heat labile, and hence has been designated as a nitrate reductase inactivating enzyme. The reduced flavin mononucleotide nitrate reductase was also inactivated, while an NADH cytochrome c reductase in nitrate-grown seedlings was inactivated but at a slower rate. The inactivating enzyme had no influence on the activity of nitrite reductase, glutamate dehydrogenase, xanthine oxidase, and isocitrate lyase. The activity of the nitrate reductase inactivating enzyme was not influenced by nitrate and was also found in the mature root of minus nitrate-grown seedlings.
TL;DR: The heightened activity of the renin-angiotensin-aldosterone system which is appropriate to normal pregnancy is an aggravating factor in established toxaemia, and may predispose to its development in some patients by failing to decline in late pregnancy.
Abstract: 1. In a prospective study involving fifty-six women, measurements of body weight, urinary creatinine, sodium and potassium and plasma sodium, potassium and renin activity were made in mid-pregnancy and at 36 weeks. The effect of sodium restriction and sodium loading on these measurements was assessed in mid-pregnancy. 2. Mean plasma renin activity was significantly higher throughout pregnancy than the normal non-pregnant mean level. It was lower at 36 weeks than in mid-pregnancy in those whose pregnancy was normal but not in those who developed toxaemia of pregnancy between 38 and 40 weeks. In mid-pregnancy in both groups sodium depletion was significantly elevated but sodium loading did not significantly depress plasma renin activity. 3. The urinary potassium/creatinine ratio in mid-pregnancy and urinary sodium/creatinine ratio at 36 weeks were lower in those who subsequently developed toxaemia, raising the possibility of a functional renal lesion which antedates the morphologically recognizable lesion of late pregnancy. 4. In a second study involving sixty-six different women plasma angiotensin II levels between 6 and 40 weeks of pregnancy were mostly above the normal range, and highest levels were observed between 21 and 30 weeks. The plasma angiotensin II levels in six women with established toxaemia of pregnancy were not significantly different from the levels in nine women with normal pregnancy of the same duration. 5. While the renal glomerular lesion is presumably the major determinant in the development of toxaemia, the heightened activity of the renin-angiotensin-aldosterone system which is appropriate to normal pregnancy is an aggravating factor in established toxaemia, and may predispose to its development in some patients by failing to decline in late pregnancy.
TL;DR: The measurement of gaseous losses of nitrogen from a red-brown earth has been investigated by direct determination of the evolved gaseus products as discussed by the authors, and the results of field investigations, enclosed growth chamber experiments, and incubation experiments have indicated that the majority of the losses as N 2 O are due to the microbial reduction of soil nitrate at anaerobic microsites within the generally aerobic soil.
Abstract: The measurement of gaseous losses of nitrogen from a red-brown earth has been investigated by direct determination of the evolved gaseous products. The results of field investigations, enclosed growth chamber experiments, and incubation experiments have indicated that the majority of the losses as N 2 O are due to the microbial reduction of soil nitrate at anaerobic microsites within the generally aerobic soil. The detection and measurement of N 2 O in the soil atmosphere by analyses for N 2 O in samples obtained from equilibrium diffusion reservoirs provided a satisfactory and convenient means of detecting losses of nitrogen and of observing the seasonal distributions of nitrous oxide in the soil profile. Aspects of this problem requiring further investigation before the magnitude of the total gaseous losses can be accurately assessed are indicated.
01 Sep 1973
TL;DR: In this article, it was shown that sheet jointing is well developed in strata which have never been deeply buried and that the domed inselbergs on which sheet joints are commonly displayed appear to survive by virtue of their joints being compressed, which is inconsistent with the sheet joints developing through radial expansion or tensional stress.
Abstract: Although the deep-seated fractures which run approximately parallel to the land surface and are known as sheeting joints are widely attributed to erosional offloading alone, there is much evidence and argument which casts doubt on this hypothesis. There is no sound mechanical reason why fractures should normally develop as a result of decompression. Sheet jointing is well developed in strata which have never been deeply buried. The domed inselbergs on which sheet jointing is commonly displayed appear to survive by virtue of their joints being compressed, which is inconsistent with the sheet jointing developing through radial expansion or tensional stress. A few inselbergs are underlain by rocks affected by sheeting joints which are not parallel to the hill profile but on the contrary dip into the slopes of the residuals. These and other types of evidence and lines of argument point to sheeting joints having developed under compressive stress. The joints determine the shape of the land surface and not vice versa.
TL;DR: Analysis of the protein composition of tomato spotted wilt virus (TSWV), purified by an improved procedure, by polacrylamide gel electrophoresis, revealed three major structural proteins and a minor one of MW 220,000d that were shown to be glycoproteins.
TL;DR: In this article, a visual, two-choice RT experiment was performed to assess the effect of practice on compatibility effects, and it was shown that identification of the position of the hand gradually becomes independent of the normal side.
TL;DR: While salvage activity was high, there was no evidence of active de novo purine synthesis by either method, suggesting that intestinal mucosa is dependent on salvage pathway activity for the provision of purine nucleotides.
TL;DR: It is shown that whole cells of Thiobacillus denitrificans reduce nitrite to NO, N 2 O and N 2 when sulphide is the electron donor and the initial product of sulphide oxidation is a membrane-bound polymeric sulphur compound which is probably a polysulphide.
TL;DR: The absence of lethal zygosis with filtrates and supernatant fluids from donors suggests a dependence on direct cell-cell contact as found in conjugation.
Abstract: When F− cells are mixed with an excess of Hfr cells there is a lethal event which results in a decrease in the number of F− survivors. We have described and discussed the parameters affecting this phenomenon of lethal zygosis, and these include the cultural conditions of both donor and recipient cells prior to mixing and the use of aeration throughout the period of the experiment. The absence of lethal zygosis with filtrates and supernatant fluids from donors suggests a dependence on direct cell-cell contact as found in conjugation. The phenomenon, which is normally observed in liquid media, also occurs on solid media, and use of these two methods has allowed examination of strains of different mating types. Whereas most Hfr strains capable of producing normal yields of recombinants showed killing activity, no F+ and only one F′ donor produced lethal zygosis. Only F− strains were sensitive to this phenomenon. The relationship between lethal zygosis and the various stages of conjugation is discussed. Images
TL;DR: In a study on 3-day maize (Zea mays) seedlings, grown on nitrate, requirements were established for the maximum extraction and optimum stabilization of nitrate reductase in vitro.
Abstract: In a study on 3-day maize (Zea mays) seedlings, grown on nitrate, requirements were established for the maximum extraction and optimum stabilization of nitrate reductase in vitro. With the primary root, 5 mm cysteine were required in the extraction medium, but for the scutellum, which has a high level of endogenous thiol, the use of additional thiol resulted in a reduced yield of a more labile enzyme. Activity of the root and scutella nitrate reductase was obtained with either NADH or NADPH, but that of the root enzyme with NADPH was only demonstrated in the absence of phosphate.Before leaf expansion, the nitrate reductase in the maize seedling was mainly in the scutellum. The enzyme present in the primary root was predominantly in the apical region (0-2 mm). In contrast, glutamate dehydrogenase was concentrated in the mature basal region of the root (30-60 mm). A high level of nitrate (approximately 100 mm) was required to saturate the induction of nitrate reductase in the root tip, mature root, and scutellum. The concentration of nitrate required to give half the maximum level of enzyme induced was the same for each region (29 mm).After leaf expansion, more than 90% of the nitrate reductase was in the shoot, mainly in the leaf blade, and a marked decrease occurred in the level of the enzyme in the scutellum. A large proportion of the glutamate dehydrogenase was still found in the root.
TL;DR: Juvenile hormone and its analogues inhibited growth of Panagrellus redivivus and of the free-living stages of Haemonchus contortus.
Abstract: Juvenile hormone and its analogues inhibited growth of Panagrellus redivivus and of the free-living stages of Haemonchus contortus. Substances extracted from nematodes had similar actions and also showed the activity of juvenile hormone in insects. Partly purified material from 1 g of freezedried juveniles of H. contortus contained about 200 Tenebrio units.
TL;DR: Consideration was given to the response curves and response surfaces that are obtained when genotypes are grown at various levels of environmental factors to illustrate genotype-environment interactions and possible relations between two parents and their F1.
Abstract: Consideration was given to the response curves and response surfaces that are obtained when genotypes are grown at various levels of environmental factors. These curves and surfaces were used to illustrate genotype-environment interactions and possible relations between two parents and their F1.
TL;DR: In this article, a general numerical procedure is described for finding a blockage coefficient when the cross section takes an arbitary shape, and some asymptotic formulae, valid for a broad range of shiplike cross sections, are also derived for cases where the clearance below the ship is small.
Abstract: Each cross section of a ship has a blockage coefficient which is uniquely dependent on its shape. A general numerical procedure is described for finding this coefficient when the cross section takes an arbitary shape. Some asymptotic formulae, valid for a broad range of shiplike cross sections, are also derived for cases where the clearance below the ship is small.
TL;DR: This paper presents results of research into computer simulation of a mixed-model assembly line, and algorithms that provide acceptable sequences of product models in various conditions are given.
Abstract: This paper presents results of research into computer simulation of a mixed-model assembly line. The problem to be solved is described and the mathematical model of the line is presented. Algorithms that provide acceptable sequences of product models in various conditions are given, and results of simulator experiments are analysed and discussed. In the final section of the paper conclusions are drawn from the results of the work, and the general usefulness of simulation for assembly work is considered.
TL;DR: In this article, the fading of radio waves reflected from the upper D -region of the ionosphere has been studied using the spaced receiver technique and full correlation analysis, and the resulting ionospheric drift velocities are shown to provide reliable estimates of the motion of the neutral air in the reflection region.
TL;DR: The hypothesis is proposed that oxytalan fibers may be part of a mechanism that regulates vascular flow that governs periodontal vasculature in mice.
Abstract: The periodontal ligament of molars in mice includes an oxytalan fiber system that extends uninterruptedly from the first to the third molar. These fibers are not anchored in bone but they coordinate the movement of the tooth to the periodontal vasculature. The hypothesis is proposed that oxytalan fibers may be part of a mechanism that regulates vascular flow.
TL;DR: It is suggested that the ATPase is involved in the movement of ions, particularly anions, and may be related to the anion accumulation mechanism, which is known to occur across the tonoplast of such tissues.
Abstract: The turnip (Brassica rapa L.) microsome fraction contains both a Mg(2+)-inhibited acid phosphatase and a salt-stimulated Mg(2+)-activated ATPase. However, as the pH optimum of the ATPase was 8.0 to 8.5, the acid phosphatase activity could be eliminated by assaying at or above pH 7.8. The ATPase was concentrated in a fraction equivalent to the smooth microsomal membranes and was not due to fragments of mitochondria. The salt-stimulated activity showed specificity for anions rather than cations. The activity was further stimulated by carbonyl cyanide m-chloro-phenylhydrazone (CCCP), 2,4-dinitrophenol, valinomycin, nigericin, and NH(4)Cl. There was a synergistic effect between CCCP and valinomycin. Activity was insensitive to oligomycin phlorizin, ouabain, and atractylate. Based on similarity to the chloroplast ATPase, it was proposed that this ATPase was situated on the outside of the vesicle.It is suggested that the ATPase is involved in the movement of ions, particularly anions, and may be related to the anion accumulation mechanism, which is known to occur across the tonoplast of such tissues.
TL;DR: There was a trend towards ewes being fatter than wethers, but this was only significant with Merinos, and other sex differences in body composition, body growth and wool growth were not significant.
Abstract: Growth rates, chemical composition of the body and wool production were measured with wethers and ewes from two genotypes of sheep grazing at two planes of nutrition. The nutritional treatments were applied after weaning at 12 kg live weight. Animals were slaughtered at 6 kg intervals between 12 and 54 kg live weight.Dorset Horn × (Border Leicester × Merino) lambs grew 57% faster than South Australian Merino lambs before weaning, produced 22% more wool and contained more fat at weaning.Post-weaning growth rates on the high and low planes of nutrition were 168 and 78g/day for Merinos and 183 and 116 g/day for Cross-breds. Despite these differences, there was virtually no effect on body composition. Sheep which were starved and re-grown also had a similar body composition to sheep grown continuously.There was, however, a nutritional effect on wool production. On the high plane of nutrition the rate of wool production was 22% higher than on the low plane of nutrition.After weaning there were only small differences in the growth rate of the two genotypes but the Merinos grew 30% more wool than Cross-breds on the high plane of nutrition and 39% more wool on the low plane of nutrition. Genotype differences in the fat and protein content of the empty body were small, but Merinos contained more ash, Ca, P and Mg.After weaning the normal pattern of allometric growth was reversed; at 18 kg live weight the sheep contained a lower proportion of fat and higher proportion of water than at 12 kg live weight. Above 18 kg live weight normal allometric growth was resumed. The fat-free empty body became progressively less hydrated but the ratio of protein: ash remained constant at 79:21 for Merinos and 81:19 for Cross-breds.There was a trend towards ewes being fatter than wethers, but this was only significant with Merinos. Other sex differences in body composition, body growth and wool growth were not significant.