Injury of mitochondrial respiration and membrane potential during iron/ascorbate-induced peroxidation

First functional events during peroxidation in mitochondria consisted in a progressive inhibition of the phosphorylating and uncoupled respiration with succinate and glutamate/malate as substrates, whereas the resting state respiration during the same period was virtually not influenced. The membrane potential registered at a time with the respiration rates was capable of being built up for a relatively long time interval with only minor decreases, and broke down rather promptly when the active respiration was highly diminished. Inhibition of respiration proceeded mainly during the initiation phase of peroxidation. Lag phases of varied length, of malondialdehyde formation which were predominantly attributed to the iron/protein ratios correlated closely with different time intervals needed to attain maximal inhibition of respiration and decrease in glutathione. Hence, the lessening of respiration, drop of membrane potential and loss of the antioxidant, glutathione, represent early stages in the causal chain of events which precede the onset of intensive lipid peroxidation.     

SYSTEMIC INSECTICIDAL ACTION OF NICOTINE AND CERTAIN OTHER ORGANIC BASES

Nicotine and nicotine salts are taken up by the roots of plants from solutions, and when 0.01–0.001 % nicotine is used the plants become toxic to Aphis fabae and to Pieris brassicae larvae and can be shown to contain nicotine. The results with Phaedon cochleariae adults and larvae are less satisfactory. No systemic action is observed when the nicotine is watered on to soil in which plants are growing and no nicotine can be detected in the plants. Apparently the nicotine is decomposed in the soil.
When applied several times to the upper surface of a bean leaf nicotine kills aphids on the underside. There is some evidence that nicotine can be translocated further through the plant following leaf applications, but the toxic action at any distance is very weak in the plants used in the present experiments and can only be produced by frequent applications of rather concentrated nicotine solutions. Leaf absorption and subsequent translocation has not been observed with nicotine salts.
The various organic bases, including some piperidine phosphonites and allied compounds tested, are of very little interest as contact or systemic insecticides against aphids.     

Cytochemische Untersuchungen über den Zusammenhang von nativer Gärungsintensität und desoxygenem Energiepotential beim anoxybiotischen Phosphatstoffwechsel

Zusammenfassung In vorliegenden Untersuchungen konnte an drei gärungsphysiologisch distinkten Zellkategorien der Nachweis geliefert werden, daß-nach 5-bzw. 24-stündiger anaerober phosphatischer Inkubierung, ausgehend vom P-Mangelstadium — in der ersten Gruppe (stark bis mittelstark gärender Hefetyp) eine M-T-Färbung von stark bis mittelstark eintritt, die in der zweiten Gruppe (mäßig bis schwach gärender Hefetyp) auf mäßig bis schwach absinkt, während in de dritten Gruppe (nicht gärender Hefetyp) der M-T-Test vollkommen negativ ausfällt. Die markant sich abzeichnenden cytologischen Befunde stehen in guter Übereinstimmung mit den gleichzeitig durchgeführten chemischen Kontrollanalysen.Als gesetzmäßiges Reaktionsprinzip wurde erkannt, daß die Intensität der anaeroben P-Regenerierung nach P-Mangelzüchtung abhängig ist vom Grad des nativen Spaltungsvermögens der Gärungszellen, welches seinerseits einen Maßstab für die Aktivierbarkeit des anaeroben Energiepotentials bildet. Dabei kommt jedoch der Gärung, was durch anabiotische Versuche sichergestellt wurde, keine ergonische Funktion in bezug auf die phosphorylierende P-Transferierung unter anoxybiotischen Bedingungen zu.