Use of Erythrocytes Sensitized with Purified Pneumococcal Polysaccharides for the Assay of Antibody and Antibody-producing Cells

A method was described for the sensitization of erythrocytes with purified type-specific pneumococcal polysaccharide antigens using chromium chloride as a coupling agent. Erythrocytes so sensitized can be used in routine passive hemagglutination and hemolysis tests as well as in the technique of localized hemolysis-in-gel for the detection of specific antibody and specific antibody-producing cells, respectively.     

Investigation of Reported Aflatoxin Production by Fungi Outside the Aspergillus flavus Group

A screening study of 121 fungus isolates, representing 29 species, for aflatoxin synthesis demonstrated this property only in Aspergillus flavus and A. parasiticus. Eight of the organisms found negative were isolates reported by other investigators to produce aflatoxin. Since similar negative reports have come from several other workers, it is concluded that only the A. flavus group of Aspergillus can presently be certified as sources of these toxins. Reasons for possible false-positive findings are discussed along with precautionary measures and differential analytical procedures useful in aflatoxin screening studies.     

Comparative Intermediary Metabolism of Vegetative Cells and Microcysts of Myxococcus xanthus

Crude extracts of both vegetative cells and glycerol-induced microcysts of Myxococcus xanthus contained the following enzyme activities: phosphofructokinase, phosphoglucoisomerase, fructose-1,6-diphosphatase, fructosediphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate carboxylase, citrate synthase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphoglucomutase, and uridine diphosphate glucose pyrophosphorylase. With the exception of isocitrate dehydrogenase, which was present at a fivefold higher concentration in microcysts, all activities in extracts from both types of cells were essentially equal. Hexokinase and pyruvate kinase could not be detected in extracts from either type of cell. Microcysts metabolized acetate at a lower rate than did vegetative cells. Most of this decrease was reflected in a substantial decrease in ability of microcysts to oxidize acetate to CO(2). In addition, microcysts and vegetative cells showed a different distribution of (14)C-label from incorporated acetate.     

Étude pédologique comparative de l'habitat et de l'environnement d'anacanthotermes ochraceus (Burgmeister)

Summary Anacanthotermes ochraceus (Burgmeister), in the oasis of Béni-Abbès (Sahara) will establish its colonies only in the low eathern garden walls and in the clay and straw walls of the houses, where it can find both the water and the malleable clayed materials it requires.Soil analyses have given information on the physico-chemical characteristics of some of the termitaria and of the surrounding sand-hill.The organic matter in the termitarium comes both from the soil and the excrement of the termite. It is high in carbon and low in nitrogen (C/N=2,5), and its mineralization in the présense of gravitational water may result in a loss of mobilizable elements such as the bases.Both the Ph and the aeration of the termitarium favour the mineralization of nitrogenous waste material by bacterial agency.The distribution of calcium carbonate and the condition in which it occurs are more important than the total amount present on account of the part it plays in the texture and structure of the materials, of which the termitarium is composed.A statistical granulometric study of the sand fraction with the results expressed as polar coordinates enables, in comparison with those obtained by mechanical analysis, the texture of the materials colonised byAnacanthotermes ochraceus (Burgmeister) to be defined.

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Zusammenfassung In der Oase Béni-Abbés (Sahara) gründen dieAnacanthotermes ochraceus (Burgmeister) ihre Kolonien nur in den Wänden der Gärten und in den Mauern der Wohnungen. Dort finden sie das nötige Wasser und die tonigen Plastikmaterialien.Die Bodenanalysen geben Auskunft über einige der characteristichen physikalischchemischen Eigenschaften der Materialien in der Termitenbauten und in dem benachbartem Erg.Das organische Material in den Termitenbauten stammt einerseits aus dem Boden und andererseits aus den Ausscheidungen der Termiten. Reich an Kohlenstoff und arm an Stickstoff (C/N=2,5) kann seine Mineralisation, in Gegenwart von gravifischem Wasser, einen Verlust von einsatzfähigen Elementen, wie den Laugen, nach sich ziehen.Die Bedingungen des Ph und der Belüftung der Termitenbauten sind günstig für eine Mineralisation der stikstoffhaltigen Abfallstoffe auf bakteriellem Wege.Die Verteilung und die Beschaffenheit des CO₃Ca sind dort wichtiger als ihre Gesamtauswertung. Der Grund dafür ist die Rolle, die sie auf der Ebene der Textur und des Aufbaus der Materialen in den Termitenbauten spielen.Die Untersuchung der sandigen Bruchstücke durch die granulometrischen Statistiken in Polarkoordinaten, verglichen mit den Ergebnissen der granulometrischen Analyse, erlauben eine Erklärung der Textur der mit Beschlag belegten kolonisierten Materialen durch dieAnacanthotermes ochraceus (Burgmeister).

     

Relationship of water potential to growth of leaves

A thermocouple psychrometer that measures water potentials of intact leaves was used to study the water potentials at which leaves grow. Water potentials and water uptake during recovery from water deficits were measured simultaneously with leaves of sunflower (Helianthus annuus L.), tomato (Lycopersicon esculentum Mill.), papaya (Carica papaya L.), and Abutilon striatum Dickson. Recovery occurred in 2 phases. The first was associated with elimination of water deficits; the second with cell enlargement. The second phase was characterized by a steady rate of water uptake and a relatively constant leaf water potential. Enlargement was 70% irreversible and could be inhibited by puromycin and actinomycin D. During this time, leaves growing with their petioles in contact with pure water remained at a water potential of —1.5 to —2.5 bars regardless of the length of the experiment. It was not possible to obtain growing leaf tissue with a water potential of zero. It was concluded that leaves are not in equilibrium with the potential of the water which is absorbed during growth. The nonequilibrium is brought about by a resistance to water flow which requires a potential difference of 1.5 to 2.5 bars in order to supply water at the rate necessary for maximum growth.

Leaf growth occurred in sunflower only when leaf water potentials were above —3.5 bars. Sunflower leaves therefore require a minimum turgor for enlargement, in this instance equivalent to a turgor of about 6.5 bars. The high water potentials required for growth favored rapid leaf growth at night and reduced growth during the day.

     

Right Internal Mammary Artery Implantation into Right Ventricular Myocardium for Revascularization of the Entire Heart: Experimental Data and Preliminary Report

The left internal mammary artery implant combined with epicardiectomy and free omental graft provides three extra-coronary sources of blood. This operation tested in dogs with 92% main-stem occlusion of three coronary arteries protected 75% of the animals. Applied clinically in over 100 patients, the operation resulted in 90% improvement. To obtain complete myocardial revascularization, the right internal mammary artery has been used as a fourth source of extra-coronary blood. In 57 animals, the right internal mammary arteries were implanted into the anterior walls of the right ventricle; in 80% this vessel formed anastomoses with the right coronary tree, and in 65% with the right and left coronary arteriolar systems. Six patients are described who underwent right internal mammary artery implantation; five of these in addition had the combined operation of left internal mammary artery implant, epicardiectomy and free omental graft. All patients had completely blocked right coronary arteries; in addition, five had advanced disease of the left coronary arterial tree.     

THE FINE STRUCTURE OF DIFFERENTIATING XYLEM ELEMENTS

Differentiating xylem elements of Avena coleoptiles have been examined by light and electron microscopy. Fixation in 2 per cent phosphate-buffered osmium tetroxide and in 6 per cent glutaraldehyde, followed by 2 per cent osmium tetroxide, revealed details of the cell wall and cytoplasmic fine structure. The localized secondary wall thickening identified the xylem elements and indicated their state of differentiation. These differentiating xylem elements have dense cytoplasmic contents in which the dictyosomes and elements of rough endoplasmic reticulum are especially numerous. Vesicles are associated with the dictyosomes and are found throughout the cytoplasm. In many cases, these vesicles have electron-opaque contents. "Microtubules" are abundant in the peripheral cytoplasm and are always associated with the secondary wall thickenings. These microtubules are oriented in a direction parallel to the microfibrillar direction of the thickenings. Other tubules are frequently found between the cell wall and the plasma membrane. Our results support the view that the morphological association of the "microtubules" with developing cell wall thickenings may have a functional significance, especially with respect to the orientation of the microfibrils. Dictyosomes and endoplasmic reticulum may have a function in some way connected with the synthetic mechanism of cell wall deposition.