Engelbert Broda

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Two groups of lithotrophic bacteria, the existence of which may be expected on evolutionary and thermodynamical grounds, have not yet been detected: (A) photosynthetic, anaerobic, ammonia bacteria, analogous to coloured sulphur bacteria, and (B) chemosynthetic bacteria that oxidize ammonia to nitrogen with O2 or nitrate as oxidant.
In experiments on the prebiotic formation of nitric oxides, anoxic mixtures of N2 and water vapour were sparked in contact with phosphate buffer solutions at various pH values. Nitrite was found in the aqueous phase, and nitrate grew from it, presumably by reaction with H2O2. In acid solutions, these anions were reduced and destroyed by Fe2+, and the same(More)
When in the primeval atmosphere ammonia approached exhaustion, bacteria resembling clostridia developed mechanisms for nitrogen fixation. The fixation was continued by the photosynthetic bacteria. In the later, oxidizing, atmosphere the combined activities of the nitrificants and the denitrificants could lead to a large-scale cyclic regeneration of free(More)
Sulphate uptake by Anacystic nidulans under aerobic conditions in the light was found to be sensitive to metabolic poisons, such as N, N′-dicyclohexyl-carbodiimide and carbonyl cyanide m-chlorophenyl hydrazone. It was also depressed by darkness. The sulphate absorption is an energy-dependent process. Sulphate uptake was also inhibited by chromate and(More)
Probably the first nitrogen fixers were anaerobic, non-photosynthetic, bacteria, i.e. fermenters. During the evolution of N2 fixation they still needed nitrogen on the oxidation level of ammonia. Because of the complexities in structure and function of nitrogenase this evolution must have required a long time. The photosynthetic and later the respiring(More)
A flow method for the measurement of the uptake of labelled substances by plant cells has been developed. Accumulation in the medium of substances released by the plants is thereby avoided, and a more precise determination of the rate of uptake—also of transients—than through the usual, static methods is possible. The time function of the stimulation of the(More)
A miniaturized quantitative biotinidase assay has been developed using biotin 6-amidoquinoline as substrate and the 100-fold enhanced fluorescence of 6-amidoquinoline measured using apolar solvents. Amidoquinoline is measured after deproteinization by ethanol/acetone using individual standardisation and solvent resistant microtiter plates. The assay was(More)