Spatial and Temporal Variations in Bacterial Macromolecule Labeling with [methyl-3H]Thymidine in a Hypertrophic Lake

The incorporation of [methyl-³H]thymidine into three macromolecular fractions, designated as DNA, RNA, and protein, by bacteria from Hartbeespoort Dam, South Africa, was measured over 1 year by acid-base hydrolysis procedures. Samples were collected at 10 m, which was at least 5 m beneath the euphotic zone. On four occasions, samples were concurrently collected at the surface. Approximately 80% of the label was incorporated into bacterial DNA in surface samples. At 10 m, total incorporation of label into bacterial macromolecules was correlated to bacterial utilization of glucose (r = 0.913, n = 13, P < 0.001). The labeling of DNA, which ranged between 0 and 78% of total macromolecule incorporation, was inversely related to glucose uptake (r = -0.823), total thymidine incorporation (r = -0.737), and euphotic zone algal production (r = -0.732, n = 13, P < 0.005). With decreased DNA labeling, increasing proportions of label were found in the RNA fraction and proteins. Enzymatic digestion followed by chromatographic separation of macromolecule fragments indicated that DNA and proteins were labeled while RNA was not. The RNA fraction may represent labeled lipids or other macromolecules or both. The data demonstrated a close coupling between phytoplankton production and heterotrophic bacterial activity in this hypertrophic lake but also confirmed the need for the routine extraction and purification of DNA during [methyl-³H]thymidine studies of aquatic bacterial production.     

Meningitis with Acinetobacter calcoaceticus in cerebrospinal fluid. A case report

A case of meningitis due to Acinetobacter calcoaceticus occurred after neurosurgery. The cerebrospinal fluid cytology showed intracellular diplococci that strongly resembled Neisseria meningitidis. However, subsequent bacteriologic studies revealed a bacterium identical to A. calcoaceticus. It is of practical importance for cytology laboratories to recognize this diplococcal form of organism.     

Galactorrhoea: Successful Treatment with Reduction of Plasma Prolactin Levels by Brom-ergocryptine

In five patients with inappropriate lactation and amenorrhoea or impotence brom-ergocryptine was found to suppress the lactation and to diminish the raised plasma prolactin levels. The responses to treatment suggest that there may be an inverse relationship between prolactin secretion and gonadotrophin secretion in man.     

NUCLEAR-CYTOPLASMIC RELATIONS IN THE MITOSIS OF SEA URCHIN EGGS : III. γ-Ray-Induced Damage to Whole Eggs and Nucleate and Anucleate Half-Eggs

Sea urchin eggs were cut into halves. The nucleate and anucleate halves and whole eggs were irradiated with γ-rays and then fertilized with normal sperm. The first mitosis of the diploid half-egg was more delayed than the division of the whole egg. There was a small, but highly significant, delay of the mitosis of the haploid half-egg, thus demonstrating cytoplasmic sensitivity to ionizing radiation. Since the sensitivity of nucleate cells is influenced by cytoplasmic volume, the problem of the role of cytoplasm in repair is considered in relation to these data and other reports in the literature.     

Ontogeny of hemoglobins: Evidence for hemoglobin M

A new autosomal codominant hemoglobin mutation alters hemoglobin M of the primitive red cell line and hemoglobin D found in definitive cells. That Hb M and Hb D are altered by the same gene mutation supports the idea that Hb M shares a polypeptide chain with Hb D. It is concluded that in the switch from primitive hemoglobins to those of the definitive type, there are at least two α chains conserved; α^A of Hb E in Hb A and α^D of Hb M in Hb D.     

The relationship of renanthera storiei and trichoglottis fasciata

The karyotypes of Renanthera storiei and Trichoglottis fasciata and the meiotic behavior in their hybrid were investigated. Considerable differences in chromosome morphology were observed for the two species. The karyotype of R. storiei was more asymmetrical with a lower mean F percentage than that of T. fasciata. Also, variation in the largest pair of chromosomes as well as in the satellite chromosomes was apparent. Meiosis in the hybrid was highly irregular. Observations on karyotypes and meiotic behavior indicate a more distant relationship between Trichoglottis and Renanthera than among Renanthera, Arachnis, and Vandopsis.     

Electron microscopy of the fate of exogenous ferritin in the feline visual cortex

Summary The ultrastructural changes occurring in the feline visual cortex 3 hours after the injection of 0.02 mls of ferritin in 1% trypan blue in artificial cerebrospinal fluid have been studied.Near the site of injection, disrupted cells contained free and membrane-bound ferritin. In less damaged areas, some signs of oedema were present in the cells, especially in astrocytes. Membrane-bound ferritin occurred occasionally in neurones and more frequently in astrocytes and oligodendrocytes. Considerable amounts of ferritin were also accumulated in phagocytic cells of unknown origin. In blood vessels, ferritin collected in the basement membrane and around collagen and, in membrane-bound form, in pale cells at the periphery of the vessels. Ferritin occurred in all parts of the intercellular space except in interglial junctions and tight junctions between vascular endothelial cells.This work was supported by a research grant from the National Health and Medical Research Council of Australia to Professor M. J. Blunt, of the School of Anatomy, University of New South Wales. The author wishes to thank Professor Blunt for his constant encouragement and support. The assistance of Mrs. Ruth Mather is gratefully acknowledged.     

Serotonin Metabolism by Monoamine Oxidase in Rat Primary Astrocyte Cultures

The oxidative deamination of serotonin (5-HT) to 5-hydroxyindoleacetic acid (5-HIAA) by rat primary astrocyte cultures was investigated in intact cells using HPLC. All detectable 5-HIAA accumulated in the extracellular medium, and its rate of production was proportional to the 5-HT concentration over the tested range of 5 x 10(-7) to 10(-4) M. At 5 x 10(-7) M 5-HT, intracellular 5-HT was detectable only in astrocytes treated with monoamine oxidase (MAO) inhibitors. These findings are consistent with the idea that 5-HT taken up into astrocytes is not stored for re-release, but is rapidly metabolized to 5-HIAA, which is then extruded from the cell. At 5 x 10(-7) M 5-HT, 5-HIAA formation in intact cells was blocked 63% by the selective high-affinity 5-HT uptake inhibitor fluoxetine. 5-HT oxidation to 5-HIAA is carried out principally by MAO-A, because clorgyline was more effective at inhibiting the production of 5-HIAA than was pargyline. Radioenzymatic determinations of MAO activity in cell homogenates supported these findings, because under these conditions clorgyline was 1,000-fold more effective than pargyline at inhibiting MAO activity toward 14C-labelled 5-HT. However, the relatively selective MAO-B substrate beta-phenylethylamine (PEA) was also oxidized, showing that these cultures also contained MAO-B activity; the Km values for MAO-A oxidation of 5-HT and MAO-B oxidation of PEA were 135 and 45 microM, and Vmax values were 88 and 91 nmol/mg of total cell protein/h, respectively. Higher concentrations of PEA (greater than 20 microM) were oxidized by both MAO-A and MAO-B isozymes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Small scale variation in decay rate within logs one year after felling: Effect of fungal community structure and moisture content

Abstract Fungal species composition, moisture content, percentage weight loss, and instantaneous decay rate (expressed by rate of CO₂ evolution) was assessed for a total of 186 8 cm³ cubes from 10 beech logs which had been decomposing on the forest floor for 14 months. There was considerable within and between branch variation in decay rate and water content. Water content at the time of sampling was not directly correlated with percentage weight loss or instantaneous decay rate, nor was it correlated with position in the log. However, wood occupied by Ascomycotina (other than Nectria ) tended to be drier than that occupied by Basidiomycotina. In particular wood occupied by Xylaria hypoxylon was drier than that occupied by all other species, although wood in which X. hypoxylon was replacing other fungi was wetter than when X. hypoxylon was alone. Variation in percentage weight loss could not be explained in terms of water content and fungal species composition at the time of sampling, but variation in instantaneous decay rate could. Thus, decay rate by Ascomycotina was significantly less ( P < 0.05) than by Basidiomycotina, and rate of CO₂ evolution from wood occupied by X. hypoxylon alone was significantly slower than from wood in which X. hypoxylon was replacing H. fragiforme or Nectria . The latter was partially correlated with water content but whether this is a cause and effect relationship is uncertain.