Geotropism and the lateral transport of auxin in the corn mutant amylomaize

Summary In coleoptiles of the amylomaize corn mutant (AM), the amyloplasts are much reduced in size in comparison with the wild type corn (WT), permitting a comparison of geotropic responsiveness as related to lateral displacement of amyloplasts and lateral transport of auxin. The amyloplasts of AM showed 30–40% lesser lateral redistribution in response to horizontal exposure in comparison with WT. With geotropic stimulation, the lateral transport of auxin in the direction of growth was 40–80% less, and the geotropic curvature by the coleoptiles was also significantly less in the mutant as compared with WT. These correlations support the hypothesis that the starch plastids serve as gravity sensors in the geotropic responses of coleoptiles.     

Die Wirkungsweise von Cercosporella herpotricboides Fron, dem Erreger der Halmbruchkrankheit des Getreides

In halt: 1. Einleitung und Aufgabenstellung.—2. Art und Ausmaß der Scnäden im Feld-versuch.—3. Wirkungen des Krankheitserregers auf Sommergetreide.—4. Bekämpfungsmöglichkeiten.—5. Besprechung der Ergebnisse.—Zusammenfassung.—Summary. —Literaturverzeichnis.     

DECREASE IN NUCLEAR FEULGEN-POSITIVE MATERIAL (DNA) UPON AGING IN IN VITRO STORAGE OF BOVINE SPERMATOZOA

The Feulgen-DNA content of sperm cells from 5 bulls was studied by means of microspectrophotometry after storage at 5°C for 2, 3, 5, and 10 days in a yolk-citrate diluent permitting slow aerobic metabolism. A subsample of sperm cells from each bull was subjected to the Feulgen technique on each of the storage days selected. The cells sampled on each of these days received a standard 12 minute, 60°C hydrolysis. Absorption measurements at 546 mµof the individual cells indicated a marked progressive decrease in the Feulgen-DNA content of the stored spermatozoa. The loss of 30 per cent of the initial DNA at the end of 5 days' storage was highly significant statistically. This decrease approximately parallels the known decrease in fertility of stored sperm cells, as well as the increase in apparent embryonic mortality resulting from the use of similarly aged spermatozoa for artificial insemination.     

Current concepts in trauma: 2. The Sunnybrook Medical Centre trauma program: the first 11 years.

Sunnybrook Medical Centre is a tertiary care teaching hospital situated in metropolitan Toronto. Its trauma unit, opened in June 1976, serves the inhabitants of metropolitan Toronto and the surrounding area (approximately 5 million). More than 3200 patients were admitted to the unit between 1976 and 1987. The criteria for admission were age at least 14 years and an Injury Severity Score (ISS) of 16 or greater, two or more significant injuries at anatomically discrete sites when the score on the Abbreviated Injury Scale was 3 or greater, or grade IV shock (systolic blood pressure of 80 mm Hg or less). The number of patients admitted annually to the unit increased over the study period. The survival rate also increased, from 76% in 1976 to 88% in 1987, although the average age and ISS of the patients remained unchanged. Less than 2% of the patients required long-term rehabilitative or chronic care. The patient profile is similar to that seen in other trauma centres in North America. The success of this program is largely the result of expeditious stabilization and transfer from referring hospitals coupled with early definitive surgical intervention.     

Lack of sensitivity to ouabain in natural killer activity

Natural killer (NK) activity against K562 target cells is not an ouabain-sensitive process. Inhibition of 40% of cytotoxicity was achieved only with an ouabain concentration much higher than that required to inhibit cell activation in other systems such as leukocyte chemotaxis and B lymphocyte plaque formation. Pretreatment of effector cells with biological agents such as phorbol-ester 12-O-tetradecanoylphorbol-13-acetate or interferon increased the cytotoxicity. This activation was not counteracted by ouabain. The effect of ouabain on NK activity was compared with a well-known ouabain-sensitive process, for example, phytohemagglutinin-induced peripheral blood lymphocyte proliferation. Ouabain completely blocked [3H]thymidine incorporation, independent of the stage of the culture when the drug was added, with exception of the last 6 h. This inhibition could be partially reversed by addition of KCl. Ouabain was equally effective when whole blood cultures were used. These results suggest that NK activity is ouabain resistant, unlike other systems of cell activation that lead or do not lead to proliferation.