Changes in fungi with age. II. Respiration and respiratory enzymes of Rhizoctonia solani and Sclerotium bataticola

Van Etten, James L. (University of Illinois, Urbana), H. Peter Molitoris, and David Gottlieb. Changes in fungi with age. II. Respiration and respiratory enzymes of Rhizoctonia solani and Sclerotium bataticola. J. Bacteriol. 91:169-175. 1966.-The rate of respiration of Rhizoctonia solani and Sclerotium bataticola decreased with age. This decrease in respiratory rate might be produced by a decrease in the specific activity of one or more enzymes involved in carbohydrate metabolism. Specific activities in cell-free extracts were measured for most of the enzymes in the hexose monophosphate shunt, Embden-Meyerhof-Parnas pathway, tricarboxylic acid cycle, and terminal electron-transport system. In addition, glucose oxidase, isocitritase, and malic enzyme were measured. In R. solani, increases in activity with age occurred for hexokinase, alpha-glycerolphosphate dehydrogenase, malic dehydrogenase, and cytochrome oxidase. Decreases occurred for phosphohexokinase, aconitase, nicotinamide adenine dinucleotide-specific isocitric dehydrogenase, reduced nicotinamide adenine dinucleotide oxidase, and at least one of the enzymes between 3-phosphoglycerate and pyruvate. In S. bataticola, increases in activity with age were observed for phosphohexokinase, pyruvic dehydrogenase, fumarase, malic dehydrogenase, and malic enzyme, whereas none of the enzymes decreased. The specific activities of the remaining enzymes did not change with age in either fungus.     

Feedback regulation of arginine biosynthesis in blue-green algae and photosynthetic bacteria

Hoare, D. S. (The University of Texas, Austin), and S. L. Hoare. Feedback regulation of arginine biosynthesis in blue-green algae and photosynthetic bacteria. J. Bacteriol. 92:375-379. 1966.-A number of blue-green algae and photosynthetic bacteria synthesize arginine from glutamate via acetylated intermediates. Cell-free extracts of these photosynthetic microorganisms contain an N-acetyl glutamate phosphokinase, which is specifically inhibited by arginine. They also contain a transacetylase which forms ornithine from alphaN-acetyl ornithine and glutamate. The transacetylase appears to be specific for l-glutamate. Arginine synthesis and its regulation by feedback inhibition in photosynthetic microorganisms differ from that in Escherichia coli and other Enterobacteriaceae.     

Ribonucleic acid and ribosomes of Bacillus stearothermophilus

Saunders, Grady F. (University of Illinois, Urbana), and L. Leon Campbell. Ribonucleic acid and ribosomes of Bacillus stearothermophilus. J. Bacteriol. 91:332-339. 1966.-The ability of some thermophilic bacteria to grow at temperatures as high as 76 C emphasizes the remarkable thermal stability of their crucial macromolecules. An investigation of the ribonucleic acid (RNA) and ribosomes of Bacillus stearothermophilus was conducted. Washed log-phase cells were disrupted either by sonic treatment or by alumina grinding in 10(-2)m MgCl(2)-10(-2)m tris-(hydroxymethyl)aminomethane buffer, pH 7.4 (TM buffer). Ultracentrifugal analysis revealed peaks at 72.5S, 101S, and 135S, with the 101S peak being the most prominent. By lowering the Mg(++) concentration to 10(-3)m, the ribosome preparation was dissociated to give 40S, 31S, and 54S peaks. These in turn were reassociated in the presence of 10(-2)m Mg(++) to give the larger 73S and 135S particles. When heated in TM buffer, Escherichia coli ribosomes began a gradual dissociation at 58 C, and at 70 C underwent a large hyperchromic shift with a T(m) at 72.8 C. In contrast, B. stearothermophilus ribosomes did not show a hyperchromic shift below 70 C; they had a T(m) of 77.9 C. The thermal denaturation curves of the 4S, 16S, and 23S RNA from both organisms were virtually identical. The gross amino acid composition of B. stearothermophilus ribosomes showed no marked differences from that reported for E. coli ribosomes. These data suggest that the unusual thermal stability of B. stearothermophilus ribosomes may reflect either an unusual packing arrangement of the protein to the RNA or differences in the primary structure of the ribosomal proteins.     

Microscopic Examination of Stools After Partial Gastrectomy

The present study was undertaken to determine the frequency with which undigested meat fibres in the stool could be found after partial gastrectomy. A sample of stool was examined in 61 patients who had undergone a partial gastrectomy and in 92 control patients. The age ranges and average ages of both groups were similar. The stools of 77 of the 92 control patients contained well-digested meat fibres, 14 showed partially digested fibres, and one patient had completely undigested meat fibres. In the postgastrectomy group, 44 of 61 patients had well-digested meat fibres and 17 showed partially digested fibres in their stools. None showed undigested fibres. The present study demonstrated that the finding of undigested meat fibres is as infrequent in postgastrectomy patients as in control patients. If undigested meat fibres are found in the stools of postgastrectomy patients, it is suggestive of pancreatic exocrine insufficiency.     

Weitere Untersuchungen über Induktion bei Amphioxus

Zusammenfassung Es wird über Versuche anBranckiostoma lanceolatum berichtet, in denen obere Urmundlippe der jungen Gastrula in das Blastocöl gleich alter anderer Gastrulä implantiert wurde.Bei Zuchttemperaturen von 17–20° C übten die entstandenen sekundären Chorden keine Induktionswirkung auf das darüberliegende nichtneuralvirtuelle Wirtsektoderm aus.Bei Temperaturen von 22–24° C trat in der Mehrzahl der Fälle Neuralinduktion ein, womit die Ergebnisse vonTung, Wu undTung (1962) bestätigt sind.Das Ausbleiben der Induktion bei niederer Temperatur bestätigt das Ergebnis V.Ubischs von 1963, wo auch bei einer Zuchttemperatur von 18° C Induktion ausblieb.Es wird die Frage diskutiert, ob die Versuchsergebnisse darauf hindeuten, daßBranchiostoma ein werdendes oder ein reduziertes Wirbeltier sei.Es wird weiterhin auf Grund der gefundenen Temperaturabhängigkeit der sekundären Neuralinduktion die Frage diskutiert, wieweit Induktion in der normalen Entwicklung stattfindet und eine Rolle für die normale Entwicklung spielt oder ob diese nur bei Störung der normalen Struktur des Keimes als ein experimentell erzeugtes Phänomen eintritt.     

A Note on a Simple and Rapid Method of Bacteriological Sampling by Means of Agar Sausages

A rapid and simple method is described for the bacteriological examination of contaminated surfaces. It uses an imprint process with 'agar sausages' sterilized in polyamide casings.