Substrate-elicited dissociation of a complex of cytochrome P-450 with a methylenedioxyphenyl metabolite

The ¹⁴C-isosafrole metabolite-rat hepatic cytochrome P-450 complex is stable to dialysis but is readily dissociated by cyclohexane (1 mM) to release free cytochrome P-450 and radioactive ligand. The ratio of cytochrome P-450: isosafrole metabolite in the complex is unity.     

Soluble carbohydrates of dry and developing seeds

Sucrose was present in seeds of 31 species at all ages and stages of their development. The raffinose family of oligosaccharides is present in most mature and dry seeds; tomato and tobacco seeds contain planteose, whereas sesame seeds contain this sugar and a higher member of the planteose series. Cotton seeds contain raffinose, stachyose, verbascose and an unidentified ketose. Free monosaccharides were not detected in any of the dry seeds; although free glucose and fructose were detected in some immature seeds, these sugars decreased in amount and eventually disappeared during seed maturation. Sucrose, stachyose, raffinose and verbascose accumulated, in developing soybeans, in that sequence. Maltose, a sugar rarely found in plant tissues, is present in immature soybean and honey locust seeds but does not occur in the other seeds examined. It increases to a maximum during development, subsequently decreases in amount during maturation and ripening and eventually disappears completely. The petioles of old leaves and stems of the soybean plant contain maltose, but the petioles of young soybean leaves, empty pods, leaf blades and roots do not.     

Evaluation of liquid nitrogen and dry ice–alcohol refrigerants for freeze marking three mammal species

Degus (Octodon degus), Patagonian cavies (Dolichotis patagonum), and mouflon (Ovis musimon) were freeze marked with instruments refrigerated in liquid nitrogen or a mixture of dry ice and alcohol. The instruments were pressed against the skin of the animal for various trial durations. Recommended exposure durations with dry ice-alcohol refrigerant were: degus—28 sec; cavies—≈ 18 sec (estimated); mouflon—12 sec. While unsatisfactory results were obtained with the liquid nitrogen refrigerant on degus and cavies, an exposure duration of 8 sec was recommended for mouflon. With mouflon, the site of the mark influenced the appropriate exposure duration for both refrigerants. With degus, moderate overexposure resulted in acceptable marks as much of the length of peripheral white hairs was exposed due to the lack of hair in the central bare area. The dry ice-alcohol refrigerant yielded much greater exposure latitude and consistency, indicating its superiority for freeze marking, especially in a zoo setting.     

Stimulation of neutrophil leukocyte chemotaxis by a cloned cytolytic enterotoxin of Aeromonas hydrophila

A cytolytic enterotoxin produced by Aeromonas hydrophila, isolate SSU, has been cloned in our laboratory. This enterotoxin lysed rabbit red blood cells, destroyed Chinese hamster ovary cells, caused fluid secretion in rat ligated ileal loops, inhibited the phagocytic function of mouse phagocytes, and was lethal to mice when injected intravenously. In this study, the effect of this cytolytic enterotoxin on the chemotaxis of human leukocytes (cell line RPMI 1788) was examined. This toxin, at concentrations from 92.5 to 370 ng/ml, significantly stimulated the chemotactic activity of human leukocytes in a dose-dependent fashion. The stimulation of leukocyte chemotaxis elicited by cytolytic enterotoxin was abolished when the toxin was neutralized, heated, or exposed to low pH values. This stimulatory effect also was inhibited by various concentrations of pertussis toxin. These results demonstrated that cytolytic enterotoxin may stimulate increased chemotaxis of human leukocytes, and suggest that human leukocytes may possess cytolytic enterotoxin receptors which may be coupled to pertussis toxin-sensitive G-protein.