Showing papers by "Macquarie University published in 1972"
TL;DR: The ripening induced by exogenous ethylene has been considered to be qualitatively identical with that which occurs naturally, and once ripening is induced it has be considered that endogenous ethylene production rises autocatalytically.
Abstract: FLESHY fruits have been divided into two classes on the basis of their respiratory behaviour during ripening: climacteric fruit, such as bananas, which undergo a large increase in respiration (climacteric rise) accompanied by marked changes in composition and texture, and non-climacteric fruit such as citrus, which show no changes in respiration that can be associated with distinct changes in the composition of the fruit1. An increase in the level of endogenous ethylene is considered to be the immediate trigger of ripening in climacteric fruits2. Fruits of this class usually produce large amounts of ethylene once ripening is under way. They may also be induced to ripen by treatment with ethylene at concentrations above about 0.1 p.p.m. for a suitable period3. The ripening induced by exogenous ethylene has been considered to be qualitatively identical with that which occurs naturally3. In both cases, once ripening is induced it has been considered that endogenous ethylene production rises autocatalytically4. Uninjured citrus fruit have been shown to produce low amounts of ethylene5. Their respiration may be increased by treatment with ethylene6 and disappearance of chlorophyll (colouring) and ageing may be more rapid18.
393 citations
TL;DR: A series of experimental runs has been conducted on a glass prepared from a natural island are calc-alkaline andesite from Fiji as discussed by the authors, and the crystallization sequence was determined for the pressure interval 9-36 kb under anhydrous conditions and with 2, 5, and 10% by weight of water carefully added.
Abstract: A series of experimental runs has been conducted on a glass prepared from a natural island are calc-alkaline andesite from Fiji. The crystallization sequence was determined for the pressure interval 9–36 kb under anhydrous conditions and with 2, 5, and 10% by weight of water carefully added. Addition of water markedly lowers the liquidus, depresses the appearance of quartz and plagioclase in the crystallization sequence, and greatly enlarges the field of garnet-clinopyroxene crystallization above 25 kb. Amphibole crystallizes in hydrous runs up to 25 kb. Electron microprobe analyses of critical phases allows calculation of controls on crystal fractionation trends. For hydrous conditions at 5–15 kb amphibole-clinopyroxene dominate fractionation and a moderate decrease in Mg/Fe and a slight increase in K/Na occurs. At 15–25 kb garnet also affects the fractionation and a moderate decrease in Mg/Fe and an increase in K/Na results. Above 25 kb garnet-clinopyroxene control the fractionation and there is a slight decrease in Mg/Fe but a significant increase in K/Na and a pronounced silica enrichment. In terms of major element chemistry, the derivation of the Fijian dacites in the second period of eruption may be satisfactorily explained by the fractionation of hydrous andesite at pressures >25 kb. Alternatively the dacites may result from lower degrees of melting of the down-going hydrous lithosphere. Similarly other members of this eruptive period may be derived according to a model of eclogite-controlled fractional melting or crystallization. Models involving amphibole fractionation at lower pressures are less satisfactory for explaining compositions in the Fijian second period of eruption, but in other environments models including amphibole-controlled fractionation may form part of a continuum of melting processes in subduction zones.
224 citations
TL;DR: On the basis of polyacrylamide gradient gel electrophoresis of leaf extracts from 24 species of higher plants, two main forms of carbonic anhydrase (EC 4.2.1.1) were recognized; the "dicotyledon" type and the "monocotylen" type.
Abstract: On the basis of polyacrylamide gradient gel electrophoresis of leaf extracts from 24 species of higher plants, two main forms of carbonic anhydrase (EC 4.2.1.1) were recognized; the “dicotyledon” type and the “monocotyledon” type. More than one band of enzyme was found on gels from most species, suggesting the possibility of carbonic anhydrase isoenzymes in higher plants.
80 citations
TL;DR: The two enzyme preparations were different in specific activity, stability in solution, and sensitivity to sulfonamides and inorganic anions, and Gel electrophoresis separated each purified preparation into two active enzyme bands.
Abstract: Carbonic anhydrase (EC.4.2.1.1) was purified from leaves of the dicotyledon Pisum sativum L. (56-fold) and from leaves of the monocotyledon Tradescantia albiflora Kunth. (24-fold). The molecular weight of the Pisum enzyme was estimated to be 188,000 ± 8,000 with subunit sizes of 28,000 ± 3,000 and 56,600 ± 3,500. It contained 1 mole zinc per 32,500 ± 2,000 g protein. The molecular weight of the Tradescantia enzyme was estimated to be 42,000 ± 2,000 with a subunit size of 27,500 ± 2,200. It contained 1 mole zinc per 34,000 ± 2,000 g protein. The two enzyme preparations were different in specific activity, stability in solution, and sensitivity to sulfonamides and inorganic anions. Gel electrophoresis separated each purified preparation into two active enzyme bands.
60 citations
TL;DR: The photochemical activities of chloroplasts isolated from bundle sheath and mesophyll cells of maize (Zea mays var. DS606A) have been measured and NADPH diaphorase activity was comparable in both types of chloroplast, and the capacity for NADP reduction appeared to be related to the degree of grana formation.
Abstract: The photochemical activities of chloroplasts isolated from bundle sheath and mesophyll cells of maize (Zea mays var. DS606A) have been measured. Bundle sheath chloroplasts are almost devoid of grana, except in very young leaves, while mesophyll chloroplasts contain grana at all stages of leaf development.Chloroplast fragments isolated from bundle sheath cells showed a light-dependent reduction of potassium ferricyanide, 2, 6-dichlorophenolindophenol, mammalian cytochrome c, plastocyanin, and Euglena cytochrome c(552). These activities were inhibited by 3-(3, 4-dichlorophenyl)-1, 1-dimethylurea at 1.25 micromolar. However, the photoreduction of NADP from water was extremely low or absent, except in chloroplasts from very young leaves, and the capacity for NADP reduction appeared to be related to the degree of grana formation.Photosystem I activity was present in bundle sheath chloroplast preparations at all stages of leaf growth and senescence examined. However, the activity was lower than in isolated mesophyll chloroplasts. NADPH diaphorase activity was comparable in both types of chloroplast.Chloroplasts isolated from bundle sheath cells of plants grown under a variety of conditions, including continuous and intermittent light, high and low light intensities, and high temperature, exhibited photosystem II activity.
60 citations
TL;DR: Laterite has been applied to such a diverse array of geomorphic features that it no longer has value as a precise descriptive term as discussed by the authors, and the persistence of error in modern studies of laterite stems from early confusion over what laterite is and how it forms.
Abstract: Although originally defined as a mottled clay which hardened on exposure to air, the term laterite has been applied to such a diverse array of geomorphic features that it no longer has value as a precise descriptive term. The persistence of error in modern studies of laterite stems from early confusion over what laterite is and how it forms. Sedentary laterite is genetically distinct from detrital laterite. Pedogenetic ironstone is younger than the weathered rock beneath it. A tropical climate is not essential for laterite to form. The influence upon weathering of lithology and relief may offset that of climate, so that relict laterites are poor paleoclimatic indicators. The value of laterite as a stratigraphic marker, and its use in denudation chronology, is also suspect.
51 citations
TL;DR: Blocking effects by adrenergic and cholinergic agents on drinking and eating behavior respectively have been demonstrated in the rat at the level of the hypothalamus and a model to explain the reciprocal interaction between the neural circuits regulating food and water intake is proposed.
46 citations
TL;DR: In this article, the kinaesthetic spatial aftereffect was used to investigate the muscular component in positional judgments, and a comparison of the results of the two experiments showed that a muscular component, dependent upon the direction of prior stimulation, was present in positional judgment.
Abstract: The kinaesthetic spatial aftereffect was used to investigate the muscular component in positional judgments. In the first experiment the magnitude of the aftereffect following 30[ddot] rotation of the limb through its longitudinal axis for 90 sec. was measured using 20 Ss. In a second experiment using 40 Ss the spatial and temporal aspects of stimulation were replicated while muscular exertion was varied. A comparison of the results of the two experiments showed that a muscular component, dependent upon the direction of prior stimulation, was present in positional judgments.
34 citations
TL;DR: The results presented help to explain the mechanism of reduction and oxidation and how phytoflavin can substitute for ferredoxin in photosynthetic electron transport by utilization of the oxidation-reduction couple, phy toflavin semiquinone/hydroquinone.
31 citations
TL;DR: In this article, the effects of either coating the leaf to make its surface impermeable to water vapour, or wetting the leaf surface, or shading it were considered, and the results obtained by the various methods are roughly similar, but anomalies need further investigation.
30 citations
TL;DR: The toxin from Hapalochlaena maculosa (the blue-ringed octopus) has been isolated in a chromatographically pure state and was shown to be chemically similar to, but distinct from, tetrodotoxin.
TL;DR: The results indicated that the agranal bundle sheath chloroplasts reduced plastocyanin via photosystem II and oxidized it via Photosystem I, and both types of maize chloroplast photoreduced oxidized plastOCyanin, but in the presence of methyl viologen, reduced plastscyanin was photo-oxidized only by the bundle sheaths.
Abstract: Photoreduction of NADP from water in agranal chloroplasts isolated from the leaf bundle sheath cells of Zea mays (var. DS 606A) or Sorghum bicolor (var. Texas 610) was dependent upon addition of plastocyanin as well as ferredoxin. Activity was further increased by the addition of ferredoxin NADP-reductase. Saturation for plastocyanin was reached at about 6 micromolar. In contrast, grana-containing chloroplasts isolated from leaf mesophyll cells of these plants or from pea (Pisum sativum L.) leaves did not require either plastocyanin or ferredoxin NADP-reductase for NADP photoreduction from water, although with some preparations plastocyanin stimulated the activity.Photosystem I activity, which was low in washed preparations of bundle sheath chloroplasts, was also stimulated by plastocyanin. The effect of plastocyanin on photosystem I activity in the grana-containing chloroplasts was similar to that on NADP photoreduction from water.In the presence of plastocyanin, the rates of NADP photoreduction from water were about the same in the agranal and granal chloroplasts, but photosystem I activity was considerably higher in bundle sheath chloroplasts. In these chloroplasts photosystem II appeared to limit the rate of NADP photoreduction.The results indicated that the agranal bundle sheath chloroplasts reduced plastocyanin via photosystem II and oxidized it via photosystem I. Both types of maize chloroplast photoreduced oxidized plastocyanin, but in the presence of methyl viologen, reduced plastocyanin was photo-oxidized only by the bundle sheath chloroplasts.
TL;DR: Petrographic evidence for hydration reactions, such as cordierite + water = gedrite + kyanite + quartz, and aluminous hypersthene+ water = aluminized anthophyllite, is shown by some granulite facies rocks in the Arunta Complex, near Alice Springs, central Australia as discussed by the authors.
Abstract: Petrographic evidence for the hydration reactions: cordierite + water = gedrite + kyanite + quartz, and aluminous hypersthene + water = aluminous anthophyllite, is shown by some granulite facies rocks in the Arunta Complex, near Alice Springs, central Australia. Electron microprobe analyses enable the reactions to be written in some detail. Preliminary thermodynamic and experimental information suggests that the reactions took place at relatively high confining pressures. The reactions may have proceeded more in response to addition of water to the system, rather than a major change in P-T conditions.
TL;DR: In this article, the aryl substituent has been shown to affect the fragmentation and abundance of skeletal rearrangement ions in the spectra of 2-hydroxy and 2-chloroethyl sulphones.
Abstract: The aryl substituent has been shown to affect the fragmentation and abundance of skeletal rearrangement ions in the spectra of aryl sulphonyl chlorides and sulphonic acids. The spectra of 2-hydroxy and 2-chloroethyl aryl sulphones contain [aryl SO]+ ions, suggesting that alkyl migration has competed successfully with aryl migration to the electron deficient oxygen atom.
TL;DR: The planar cleavage in graywacke, siltstone, and pelite of the Michigamme Slate appears to have been produced by tectonic dewatering as discussed by the authors.
Abstract: Cleavage in graywacke, siltstone, and pelite of the Michigamme Slate appears to have been produced by tectonic dewatering. Clastic dikes, from paper-thin dikelets to zones 10 m wide, are intruded parallel to cleavage in many outcrops. In other places, liquefication and mobilization have homogenized the sediments into massive, structureless rocks. The planar cleavage which pervades all rock types is produced by pelitic folia formed during tectonic dewatering. Ellipsoidal concretions with the same ductility as the host siltstone indicate large plane strains. Maximum shortening is perpendicular to cleavage with greater than threefold extension in the cleavage. Lengths parallel to fold axes are essentially unchanged, but stratigraphic thicknesses may be grossly exaggerated by deformation. Tectonic dewatering of the Michigamme Slate may have occurred after tectonic dewatering of the underlying Siamo Slate.
TL;DR: The development of wingbud epidermis during the last larval stage of cabbage aphids is described at the ultrastructural level, and compared with its development in juvenile hormone (JH) treated specimens.
TL;DR: In this article, 100 male and female students between the ages of 5 and 19 years were subjected individually to an obviously and unanimously wrong decision by a group of their same-sex peers.
Abstract: Summary. 100 male and female students between the ages of 5 and 19 years were subjected individually to an obviously and unanimously wrong decision by a group of their same-sex peers. Conformity differed among the age groups but not between the sexes. Maximum conformity was found in the adolescent age group.
TL;DR: There is the possibility of an undetected or unknown metabolic disturbance in autistic children in New South Wales, and a rationale is given for the suggested levodopa therapy with a concurrent decarboxylase inhibitor.
Abstract: In an investigation of 25 autistic and 69 normal children in New South Wales, there was an overrepresentation of relatively hypopigmented autistic children and an underrepresentation of relatively hyperpigmented autistic children. The difference was significant at better than the 0·25 level of confidence. This indicates the possibility of an undetected or unknown metabolic disturbance in autistic children in N.S.W. A rationale is given for the suggested levodopa therapy with a concurrent decarboxylase inhibitor.
TL;DR: Le Podolactone E, qui a la structure (4), empêche très activement la croissance des cellules végétales, c'est le plus actif des podolactones isolés jusqu'à présent.
Abstract: Le Podolactone E, qui a la structure (4), empeche tres activement la croissance des cellules vegetales. C'est le plus actif des podolactones isoles jusqu'a present.
TL;DR: Evidence was found which suggested a secular trend in the onset of puberty with fluctuations paralleling times of economic crisis, which was found to be normally distributed within the age range 9 years to 15 years 8 months.
Abstract: SYNOPSIS
Statistics derived from a sample of 1391 schoolgirls drawn from both state and private schools showed the mean age of menarche to be 12.65 years. Selected schools were included to give a representative sample in terms of geographical and social class distribution. The onset of puberty was found to be normally distributed within the age range 9 years to 15 years 8 months. After an examination of the results of previous Australian studies, evidence was found which suggested a secular trend in the onset of puberty with fluctuations paralleling times of economic crisis.
TL;DR: In this article, the photo-oxidation of cytochrome f (cytochrome c(554)) in bundle sheath cells isolated from leaves of maize (Zea mays var. DS 606A) has been compared with that in intact maize leaf and in isolated pea leaf cells (Pisum sativum L.).
Abstract: The photo-oxidation of cytochrome f (cytochrome c(554)) in bundle sheath cells isolated from leaves of maize (Zea mays var. DS 606A) has been compared with that in intact maize leaf and in isolated pea leaf cells (Pisum sativum L.). In all cases, illumination with red light caused a negative absorbance change at 554 nm which was attributed to the oxidation of cytochrome f. The extent of this change was greater using monochromatic red light at wavelengths above 700 nm compared with wavelengths below 700 nm. 3-(3,4-Dichlorophenyl)-1, 1-dimethylurea abolished this difference in bundle sheath cells. After illumination for 1 minute or longer in bundle sheath cells, reduction of cytochrome f in the dark was rapid only if the wavelength of the illuminating light was below 700 nm. In the presence of 3-(3,4-dichlorophenyl)-1, 1-dimethlyurea, reduction was slow after illumination at all wavelengths.Cytochrome f photo-oxidation was also followed in cells of a mutant of Chlamydomonas reinhardi, ac-21, which has isolated chloroplasts that exhibit photochemical reactions similar to those shown by isolated bundle sheath chloroplasts. No evidence was obtained for photoreduction of cytochrome f in the mutant.It was concluded that in the chloroplast of the intact bundle sheath cell of maize there is electron flow between photosystem II and cytochrome f resulting in photoreduction of the cytochrome.
TL;DR: The pH dependence of the photoreduction of ferricyanide and the photOREduction of NADP from water and photosystem I activity have been compared in isolated chloroplasts from mesophyll and bundle sheath cells of Zea mays.
Abstract: The pH dependence of the photoreduction of ferricyanide and the photoreduction of NADP from water and photosystem I activity have been compared in isolated chloroplasts from mesophyll and bundle sheath cells of Zea mays. The maximum activity of photoreduction of ferricyanide occurs at pH 8.5 in isolated mesophyll chloroplasts. The addition of methylamine does not cause a marked shift in the pH maximum, but brief sonication lowers the pH maximum to 7.0. In contrast, isolated bundle sheath chloroplasts have a pH maximum at 7.0 and the shape of the pH versus activity curve is similar to that of sonicated mesophyll chloroplasts. When photoreduction of ferricyanide by the isolated chloroplasts is measured at their pH maxima, the values for bundle sheath chloroplasts are about half those of methylamine-treated mesophyll chloroplasts on a chlorophyll basis. The pH maxima for the photoreduction of NADP from water and photosystem I activity are similar in both mesophyll and bundle sheath chloroplasts with maximum activity occurring at pH 7.0 in both cases. In the presence of added plastocyanin and ferredoxin NADP-reductase, the photosystem I activities of both sonicated mesophyll and sonicated bundle sheath chloroplasts are significantly higher than those of the unsonicated preparations. On a chlorophyll basis, photosystem I activity of bundle sheath chloroplasts is at least twice that of mesophyll chloroplasts.
TL;DR: In this paper, the plant growth inhibitory activities of a number of compounds related to the podolactones were determined using a pea-stem growth system and some conclusions regarding the effects of structure on activity were presented.
Abstract: The plant-growth inhibitory activities of a number of compounds related to the podolactones were determined using a pea-stem growth system. Some conclusions regarding the effects of structure on activity are presented.
TL;DR: It was found that drug induced depletion of peripheral noradrenaline, but not adrenaline depletion, significantly retarded the rate of acquisition of the response and was discussed in relation to recent empirical findings on the sympathetic nervous system during aversive conditioning.
TL;DR: The 2-acetoxyethyl aryl sulphones were found unsuitable for a comparative study with the corresponding chlorides and alcohols as their predominant fragmentation involved cleavage of the aliphatic carbon-sulphur bond as mentioned in this paper.
Abstract: The 2-acetoxyethyl aryl sulphones were found to be unsuitable for a comparative study with the corresponding chlorides and alcohols as their predominant fragmentation involved cleavage of the aliphatic carbon-sulphur bond with charge retention on the aliphatic part of the molecule The expected McLafferty rearrangement to yield an intermediate vinyl species was only a minor fragmentation path.
Indirect evidence for alkyl migration in the molecular ion was found in the spectrum of 2-acetoxyethyl 1-paranitro phenyl sulphone. The spectra of the aryl vinyl sulphones revealed intense [Aryl SO]+ ions resulting from preferred migration of the vinyl group from sulphur to oxygen.
TL;DR: The high production of apterae on low amino acid diets is not associated with high corpus allatum activity of the parent aphids, and there was no interaction between the components within the range of concentrations tested.
TL;DR: It is concluded that no substantial increase in the amount of ribosomal material accompanies the increased in the rate of protein synthesis early in the climacteric period.
TL;DR: This paper showed that agreement with certain items claimed by Rudin (1961) to be anti-rational-authoritarian is positively related to neuroticism and negatively related to socio-economic status and intelligence.
Abstract: Evidence is presented to show that agreement with certain items claimed by Rudin (1961) to be anti-rational-authoritarian is positively related to neuroticism and negatively related to socio-economic status and intelligence, whereas agreement with proauthoritarian items from the same scale is not related. This evidence is held to support Rudin's argument that rational and irrational authoritarianism (as exemplified by the F-scale) are independent, and that pathology is related to rejection of the former as well as acceptance of the latter.
01 Jan 1972
TL;DR: In this paper, the responses to auxin and gibberellin of a system of excised stem segments from etiolated dwarf peas have been described, and differences in the effects of these two hormones could be distinguished on excised hook and tip segments.
Abstract: The responses to auxin and gibberellin of a system of excised stem segments from etiolated dwarf peas have been described previously (Adamson, Low and Adamson, 1968). In this system, differences in the effects of these two hormones could be distinguished on excised hook and tip segments.
01 Jan 1972
TL;DR: In this article, a comparison of the photochemical activities of granal and agranal chloroplasts isolated from the same plant to make a comparison between the two types of chloroplast is made.
Abstract: Plants possessing the C4-dicarboxylic (HATCH-SLACK) pathway of photosynthesis are characterized by the presence of two types of chloroplasts, which differ in their structure, enzymic content and pathway of photosynthesis (HATCH & SLACK 1970) Differences in chloroplast ultrastructure, especially with respect to grana formation are particularly marked in certain of these plants such as sugar cane, maize and Sorghum Chloroplasts of the mesophyll cells contain grana, while the mature chloroplasts of the bundle-sheath cells are essentially agranal, possessing at most, a few rudimentary grana (WEIER et al 1967) Mesophyll and bundle-sheath chloroplasts of maize are illustrated in Figure 1 In addition to the differences in their ultrastructure and pathway of C02 fixation, the chloroplasts differ in the composition of their lipids (BISHOP et al 1971)
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Fig 1
Ultrastructure of mesophyll and bundle-sheath chloroplasts of maize A, mesophyll chloroplasts; B, bundle-sheath chloroplasts; g, grana, s, starch granule Arrows indicate areas in the bundle-sheath chloroplasts which appear to contain small grana
and electron transfer proteins (WOO et al 1970) The occurence of two morphologically distinct types of chloroplast in maize, and the availability of methods for their seperation, allows a comparison of the photochemical activities of granal and agranal chloroplasts isolated from the same plant to be made The studies reported here revolve around two fundamental questions Firstly, do the agranal chloroplasts of C4 plants such as maize the capacity to photoreduce NADP from water and thereby produce reducing potential for photosynthesis? Secondly is grana formation necessary for photosystem II activity? As the question of the realationship between photosystem II activity and grana formation is not confined to chloroplasts of C4 plants, the photochemical activities of some algal chloroplasts which do not show the typical granal structure found in the chloroplasts of higher plants, have also been examined