Showing papers in "Australian Journal of Biological Sciences in 1949"
TL;DR: Several aspects of the processes of digestion in the insects Blattella germanica, Periplaneta americana, and Tenebrio molitor are reported.
Abstract: Several aspects of the processes of digestion in the insects Blattella germanica, Periplaneta americana, and Tenebrio molitor are reported. In Blattella starved for 2 days, a meal of coloured starch reaches the midgut within 10 minutes and the rectum within 5 hours. The pH of the gut contents on a starch diet is approximately 4.5 in the crop, 6.0 in the midgut, and 8.0 in the hindgut. A protein diet raises the pH of the crop to about 6.0, but does not change that of the other regions. There is a gradient of decreasing redox potential from the crop to the hindgut where the Eh approximates - 0.1 V. at pH 8.0.
119 citations
TL;DR: The origin of both the tyloses and the gumt which are commonly observed in the heartwood vessels of numerous species has been traced to the ray cells.
Abstract: The origin of both the tyloses and the gumt which are commonly observed in the heartwood vessels of numerous species has been traced to the ray cells. Tyloses are developed in the heartwood of species in which the width of the aperture of the pits from vessels to ray cells exceeds approximately 10 Ii; in woods in which the width of the pit apertures is less than approximately 10 Ii gum is secreted into the heartwood vessels.
106 citations
TL;DR: The pH of the midgut digestive juices of two species of carnivorous lepidopterous larvae and of 40 species of adult Lepidoptera belonging to 16 families was determined and it is possible to generalize that midGut alkalinity is characteristic of the order Lepidsoptera and that it is not dependent upon feeding habits.
Abstract: The pH of the midgut digestive juices of two species of carnivorous lepidopterous larvae and of 40 species of adult Lepidoptera belonging to 16 families was determined. In all species it was alkaline. From these records, and from those available from the literature for phytophagous, wool-eating, and wax-eating lepidopterous larvae, it is possible to generalize that midgut alkalinity is characteristic of the order Lepidoptera and that it is not dependent upon feeding habits.
50 citations
TL;DR: The morphology of the fowl spermatozoon, as revealed by use of the electron microscope and such techniques as partittl enzymic digestion and disruption with distilled water, is described in detail and compared with that observable by light microscopy.
Abstract: The morphology of the fowl spermatozoon, as revealed by use of the electron microscope and such techniques as partittl enzymic digestion and disruption with distilled water, is described in detail, and compared with that observable by light microscopy.
49 citations
TL;DR: The method which was used allowed measurements to be made close to the mucosa of the alimentary canal of anaesthetized animals in which the circulation was left intact, and the procedure ensured that conditions in the normal gut were very little disturbed.
Abstract: As a preliminary to the study of the relative importance . of aerobic mechanisms in the metabolism of Nippostrongylus muris, Nematodirus spathiger, Nematodirus filicollis, and Haemonchus contortus at oxygen pressures of the normal environmental fluids of these parasites, the determination of oxygen in the contents of the small intestine of the rat and sheep, and the abomasum of the sheep, has been carried out. The method which was used allowed measurements to be made close to the mucosa of the alimentary canal of anaesthetized animals in which the circulation was left intact, and the procedure ensured that conditions in the normal gut were very little disturbed.
40 citations
TL;DR: The distribution of alkaline phosphatase in insect tissues has been studied by a histochemical technique and a function of this kind is not evident in such sites as muscles and nerves.
Abstract: The distribution of alkaline phosphatase in insect tissues has been studied by a histochemical technique. The enzyme is widely distributed in the alimentary tract, storage tissue, nervous tissue, in parts of the reproductive system, in certain muscles, and some glands. It thus appears to be inv~lved in a variety of functions. Many examples of both the histological and cytological distribution are explained by the relation of the enzyme to mechanisms of transport across cell boundaries. But a function of this kind is not evident in such sites as muscles and nerves. The presence of deposits of inorganic phosphate in the alimentary tract and malpighian tubules of some species is recorded.
32 citations
TL;DR: Since wool-growth rate is strongly influenced by the plane of nutrition, any measure of inherent wool-producing capacity in the sheep must take this into account, and the relation of these three factors to each other must be known.
Abstract: Since wool-growth rate is strongly influenced by the plane of nutrition, any measure of inherent wool-producing capacity in the sheep must take this into account, and the relation of these three factors to each other must be known. On general grounds, the relation of wool-growth rate to nutrient intake seems likely to follow the familiar law of diminishing returns which introduces the concept that for each sheep there may be an asymptotic value of wool-growth rate characteristic of the individual. From this and other considerations, it was postulated that these relationships could be described by an equation of the form where y = wool-growth rate, x = nutrient intake rate at or above maintenance levels, Xo = the nutrient intake rate for which y = 0, A = the asymptotic value of y, and k' = a constant dependent on the nutritive qualities of the diet employed:
21 citations
TL;DR: There is a close correlation between the presence of aggregates of the parasite and the progressive liquefaction of the somatic muscular tissues of the gempylid fish Thyrsites atun.
Abstract: The association between a myxosporidian parasite, Chloromyxum thyrsites, and "milky" specimens of the gempylid fish Thyrsites atun has been previously described by Johnson and Cleland (1910) and Gilchrist (1924). This association has been again confirmed in the present work with the addition of observations, from post-mortem studies, which show that there is a close correlation between the presence of aggregates of the parasite and the progressive liquefaction of the somatic muscular tissues (the condition of "milkiness" which may affect from 5-7 per cent. of the commercial catches of Thyrsites atun).
18 citations
TL;DR: None of the haemoglobins obtained from the parasites showed properties supporting the view that there is a linear relationship between log K and the "span," and all showed an unusually low affinity for carbon monoxide.
Abstract: Haemoglobins from Nippostrongylus muris, Nematodirus·spp., and Haemonchus contortus were purified by ammonium sulphate fractionation and their properties examined. All the haemoglobins showed a very high affinity for oxygen; the tension of half saturation (P50) for Nematodirus haemoglobin of concentrations about 1 x 10-4 g.-atoms of iron per 1. at pH 7.4 was in the region of 0.04 mm. of mercury. The P50 for H. contortus haemoglobin was similar to that of Nematodirus .spp.; N. muris haemoglobin had a somewhat higher p:;o' The. parasite haemoglobins all showed an unusually low affinity for carbon monoxide, the equilibrium constant, K = [HbCO] X p02/[Hb02] X pCO, having a value of about 1. The "span," the distance between the a-bands of oxyhaemoglobin and carboxyhaemoglobin, varied from 60 to 65 A. for the three parasites. None of the haemoglobins obtained from the parasites showed properties supporting the view that there is a linear relationship between log K and the "span."
17 citations
TL;DR: Three histochemical tests, which demonstrate mucoid substances of vertebrate origin, have been applied to a variety of insect tissues, and the significance of the observed distribution of mucoids in insects is discussed, particularly in relation to the functions of the peritrophic membrane and the salivary glands.
Abstract: Three histochemical tests, which demonstrate mucoid substances of vertebrate origin, have been applied to a variety of insect tissues. Mucoid materials seem to be absent from the contents of the insect midgut, but a positive reaction may be given by. the striated border of the epithelium. Goblet cells of the larval midgut of Lepidoptera and rectal glands of all of the insects studied give a negative reaction, but the salivary glands of the cockroach, grasshopper, larval calliphorids, and worker honeybee all contain mucoid substances. In general, these materials seem to be of less frequent occurrence in insects than they are in most other animal phyla. The significance of the observed distribution of mucoid substances in insects is discussed, particularly in relation to the functions of the peritrophic membrane and the salivary glands.
16 citations
TL;DR: The history of the wheat industry in South Australia is reviewed in this article to provide a background for discussion of the fomls of trend observed in yield, the period chosen for examination was 1896-1941, and the analysis extends to practically the entire wheat belt, the basic territorial unit used for assessing yield being the hundred, the mean area of which is approximately 118 square miles.
Abstract: The history of the wheat industry in South Australia is reviewed to provide a background for discussion of the fomls of trend observed in yield. The period chosen for examination was 1896-1941, and the analysis extends to practically the entire wheat belt, the basic territorial unit used for assessing yield being the hundred, the mean area of which in South Australia is approximately 118 square miles. As a preliminary to the evaluation of the trends it was necessary to estimate and to eliminate the effects of variations in seasonal rainfall; the statistical technique used was that of partial regression, and reasons are given for the choice of rainfall variates.
TL;DR: Changes in amounts of certain metabolites and possible respiratory intermediates in the flesh of Australian Granny Smith appl~ during storage at ODC are made.
Abstract: A survey has been. made of changes in amounts of certain metabolites and possible respiratory intermediates in the flesh of Australian Granny Smith appl~ during storage at ODC.
TL;DR: Ascorbic acid has been detected histologically in many, but not in all tissues of insects, and is particularly abundant in the midgut epithelium and nervous tissue.
Abstract: Ascorbic acid has been detected histologically in many, but not in all tissues of insects. It is particularly abundant in the midgut epithelium and nervous tissue, and is usually confined to the cytoplasm. In two insta:n~es nucleoli have given a' positive reaction for ascorbic acid.
TL;DR: In this article, a statistical procedure is developed whereby the precision of estimation of growth increments and various growth indices is greatly increased, especially where the variability of the plant' material is great.
Abstract: A statistical procedure is developed whereby the precision of estimation of growth increments and various growth indices is greatly increased, especially where the variability of the plant' material is great.
TL;DR: Suitable washing techniques, which do not appreciably affect sperm motility, and enzymic digestion, have made it possible to give a clear picture of the finer structures in the human spermatozoon, using the electron microscope.
Abstract: Suitable washing techniques, which do not appreciably affect sperm motility, and enzymic digestion, have made it possible to give a clear picture of the finer structures in the human spermatozoon, using the electron microscope.
TL;DR: Two large satnples of "mixed" rumen bacteria were prepared from abattoir sheep, one from sheep coming from "green" feed conditions and the other from "dry"-fed sheep.
Abstract: Two large satnples of "mixed" rumen bacteria, virtually free from protozoa and feed residues, were prepared from abattoir sheep, one from sheep coming from "green" feed conditions and the other from "dry"-fed sheep.
TL;DR: The time intervals for complete reduction of dehydroascorbic acid by hydrogen sulphide at pH 4, 5, 6, and 7 at temperatures of 0°, 25°, and 40°C have been determined as mentioned in this paper.
Abstract: The time intervals for complete reduction of dehydroascorbic acid by hydrogen sulphide at pH 4, 5, 6, and 7 at temperatures of 0°, 25°, and 40°C. have been determined.
TL;DR: Evidence is presented which indicates that the haemoglobin of Nippo$rongylus muris may be oxygenated in vivo, at least sometimes, and in vitro at 37°C.
Abstract: In the parasites examined, the amounts of water-soluble haematin compounds, of which haemoglobin formed the large part, varied considerably; Nippo$rongylus murls contained about 6 mg. (as haematin) per g. dry wt. of tissue, Nematodirus spp. and Haemonchus contortus about 0.8 mg. per g. dry wt. Evidence is presented which indicates that the haemoglobin of Nippo$rongylus muris may be oxygenated in vivo, at least sometimes. The haemoglobin in the living parasites was easily oxygenated and deoxygenated; when the oxygen tension in the medium surrounding the parasites in vitro at 37°C. fell below about 13 mm. of mercury (Nippostrongylus muris) or 9 mm. of mercury (Haemonchus contortus and Nematodirus spp.) the oxyhaemoglobin became deoxygenated.
TL;DR: Results indicate that Haemonchus contortus in the sheep abomasums probably respires at a relatively lower rate than either of the intestinal parasites in vivo, and in vivo the oxygen consumption rates may sometimes reach 80 per cent.
Abstract: Nippostrongylus muris, Haemonchus contortus, Nematodirus spathiger, and N. filicollis are all capable of utilizing oxygen for respiratory purposes even when it is present at very low oxygen tensions. Thus with a partial pressure as low as 5 mm. of mercury the respiration of Nippostrongylus muris may reach 40 per cent. of its maximum rate, whereas Nematodirus spp. and H. contortus may respire at 25 and 12 per cent. of their maximum rates respectively. Further, the results indicate that in vivo the oxygen consumption rates may sometimes reach 80 per cent. of the maximum in vitro rate in the case of Nippostrongylus muris in the small intestine of the rat and 40 per cent. in the case of Nematodirus spp. in the small intestine of the sheep. Haemonchus contortus in the sheep abomasums probably respires at a relatively lower rate than either of the intestinal parasites in vivo.
TL;DR: Five sheep (two Merinos, two Corriedales, and one crossbred) were subjected to unilateral thoracic sympathectomy and fleece samples were collected from tattooed areas of skin on both the symp Athectomized and control sides.
Abstract: Five sheep (two Merinos, two Corriedales, and one crossbred) were subjected to unilateral thoracic sympathectomy. Fleece samples were collected at 28-day intervals, for a period of seven months, from tattooed areas of skin on both the sympathectomized and control sides.
TL;DR: The hormone-like character and general structural similarity of certain substituted aryl-acetates and -oxyacetates or their potential precursors to that of indole-3-acetic acid suggest that these compounds may act indirectly by altering the activity of this natural plant hormone.
Abstract: The use of synthetic plant growth-regulating compounds is of increasing economic importance in agriculture but little is known of their fundamental mechanism of action. The hormone-like character and general structural similarity of certain substituted aryl-acetates and -oxyacetates or their potential precursors (Zimmerman and Hitchcock 1941-42) to that of indole-3-acetic acid (LA.A.) suggest that these compounds may act indirectly by altering the activity of this natural plant hormone. Tang and Bonner (1947) have partially characterized an enzyme prepared from pea epicotyls (and referred to here as LA.A. oxidase) which oxidizes and inactivates LA.A. On adding 11 auxin analogues to a crude enzyme preparation they found no change in the rate of LA.A. inactivation. However, as these workers used a substrate (LA.A.) concentration that was rate-limiting, the only rate-change necessarily to be detected would have been a decrease due to competition with the substrate.
TL;DR: It is probable that a severe physiological reaction to leaf roll has a well-defined genetic basis, so that the development of hybrids hypersensitive to this virus is possible, and this provides a new approach to the problem of leaf-roll resistance in the potato.
Abstract: A modified technique which has facilitated the detection of phloem necrosis in leaf-roll-infected potato plants is described. Placed on a quantitative basis, the necrotic reaction has proved valuable in the estimation of leaf-roll severity in varieties and hybrids. Quantitatively, phloem necrosis has been shown to be tl varietal character which can be influenced by nutritional and environmental conditions. Among varieties and hybrids, a range of necrotic reactions in the phloem from mild to very severe was found, and these reactions were correlated with external symptoms. Severe reactors show a progressive decrease in the amount of phloem necrosis from the stem base to the tip. It is probable that a severe physiological reaction to leaf roll has a well-defined genetic basis, so that the development of hybrids hypersensitive to this virus is possible. This provides a new approach to the problem of leaf-roll resistance in the potato.
TL;DR: The main objective of work described in this paper was to find out what differences occurred in the degree of latent infection of Washington Navel oranges grown under diHerent circumstances and treated in various ways.
Abstract: The main objective of work described in this paper was to find out what differences occurred in the degree of latent infection of Washington Navel oranges grown under diHerent circumstances and treated in various ways. Observations were also made of fungi occUrring as latent infections and on the conditions for, and mode of, infection by Colletotrichum gloeosporoides, the principal form concerned.
TL;DR: The lipid fraction appeared to be the only one essentially concerned in reactions with natural antisera from sheep, and further work was carried out to determine the nature of the serologically active lipid.
Abstract: Protein, polysaccharide, and lipid fractions were prepared from Haemonchus contortus. The lipid fraction appeared to be the only one essentially concerned in reactions with natural antisera from sheep, and further work was carried out to determine the nature of the serologically active lipid. It was found to be hydrophilic, acidic, susceptible to oxidation, free from protein and polysaccharide, and to have a molecular weight greater than 1000. Its biochemical significance, role in the activity of the boiled antigen, and possible relation to other lipoidal antigens are discussed.
TL;DR: In Duboisia Leichhardtii and D. myoporoides macrosporogenesis and the development of the embryo-sac are similar to the descriptions reported for other genera of the family Solanaceae.
Abstract: In Duboisia Leichhardtii and D. myoporoides macrosporogenesis and the development of the embryo-sac are similar to the descriptions reported for other genera of the family Solanaceae. The haploid number of chromosomes in both species is 30. A generative and vegetative nucleus is formed in each micros pore which later becomes filled with starch grains and uninucleate as a result of degeneration of the vegetative nucleus. At maturity the pollen grains are devoid of starch and are uninucleate. Division of the generative nucleus to form two male nuclei presumably occurs just prior to the discharge of the pollen tube.
TL;DR: The total vitamin A potency of butterfat has been determined on samples from three different Victorian districts and from King Island in Bass Strait in 1945 and 1947-48 as mentioned in this paper, using the Carr-Price test.
Abstract: The total vitamin A potency of butterfat (dertved from cheese or butter) has been determined on samples from three different Victorian districts and from King Island in Bass Strait in 1945 and 1947-48. Carotene was determined colorimetrically and the Carr-Price test was used for vitamin A. The glycerol dichlorhydrin reagent was too insensitive.