for the estimation of Bayer 22,408 residues in milk, butterfat, or plant samples, especially when all the material that may cause interference can be removed by the repeated solvent extractions, evaporation, and chromatography. However, to avoid excessively high reagent blanks, certain general precautions should be followed.First, all glassware should be cleaned with cleaning solution, thoroughly rinsed with water, and dried in an oven at 100°C. Second, contact of the analytical solution with stopcock grease, rubber, cork, soap powder, or soap film must be avoided, as these materials can introduce additional fluorescence and cause high readings.With the use of a Fisher Nefluoro-Photometer and the filters specified, the range of the method is limited to 5 to 100 of Bayer 22,408 in the samples analyzed. However, with an Aminco-Bowman spectrophotofluorometer, the activation and fluorescence maxima under the conditions of the method were 372 and 480 µ, respectively. As little as 0.01
The lipid composition of the chemoautotroph
Ferrobacillus ferrooxidans
has been examined. Fatty acids represent 2% of the dry weight of the cells and 86% of the total are extractable with organic solvents. About 25% of the total fatty acids are associated with diacyl phospholipids. Polar carotenoids, the benzoquinone coenzyme Q-8, and most of the fatty acids are present in the neutral lipids. The phospholipids have been identified as phosphatidyl monomethylethanolamine (42%), phosphatidyl glycerol (23%), phosphatidyl ethanolamine (20%), cardiolipin (13%), phosphatidyl choline (1.5%), and phosphatidyl dimethylethanolamine (1%) by chromatography of the diacyl lipids, by chromatography in four systems of the glycerol phosphate esters derived from the lipids by mild alkaline methanolysis, and by chromatographic identification of the products of acid hydrolysis of the esters. No trace of phosphatidylserine (PS), glycerolphosphorylserine, or serine could be detected in the lipid extract or in derivatives of that extract. This casts some doubt on the postulated involvement of PS in iron metabolism. After growth in the presence of
14
C and
32
P, there was essentially no difference in the turnover of either isotope in the glycerolphosphate ester derived from each lipid in cells grown at
p
H 1.5 or 3.5.
The two vital aspects of chemoautotrophic metabolism are the generation of energy (ATP or the equivalent) and a simultaneous production of reducing power coupled to the enzymic oxidation of an inorganic substrate. Aleem and Nason' reported that in the obligately chemoautotrophic bacterial genus Nitrobacter the enzymic oxidation of nitrite is catalyzed by a cytochrome-containing electron transport particle via cytochrome c and cytochrome oxidase-like components.They subsequently demonstrated2 the coupling of this oxidation with the generation of high-energy phosphate bonds which were identified as adenosine triphosphate (ATP). The over-all reaction is:
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