NUCLEIC ACIDS OF CHLOROPLASTS AND MITOCHONDRIA IN SWISS CHARD.
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Nucleic acids in young leaves of Swiss chard have been studied by light and electron microscope techniques. Leaf DNA has also been characterized by density gradient centrifugation and shown to contain a minor band of higher guanine plus cytosine (GC) content, presumably attributable to chloroplasts. The chloroplasts were faintly stained by the Feulgen reaction; radioautography demonstrated the incorporation of tritiated thymidine in the cytoplasm and in some nuclei. The Feulgen stainability and most of the radioactivity were removable with DNase. Under the electron microscope, both mitochondria and chloroplasts were found to contain filamentous and particulate components within the matrix areas. The morphology of the filamentous component was dependent on the fixation, being partially clumped after OSO(4) or formalin, but finely filamentous after Kellenberger fixation. The filaments were stainable with uranyl acetate, and were extractable with DNase following formalin fixation under conditions in which nuclear DNA was also extracted. The particulate component, after formalin fixation and uranyl staining, was prominent in chloroplasts from young leaves, but was only sparsely distributed in mitochondria. The stainability was removed with ribonuclease. We have concluded that chloroplasts and mitochondria of Swiss chard possess a filamentous component that contains DNA, probably responsible for both cytoplasmic thymidine incorporation and the minor band in CsCl centrifugation. A particulate ribosome-like component that contains RNA is also present. (+info)
EFFECT OF CAROB POD EXTRACT ON CELLULOLYSIS, PROTEOLYSIS, DEAMINATION, AND PROTEIN BIOSYNTHESIS IN AN ARTIFICIAL RUMEN.
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Carob pod extract and its tannin and sugar fractions were compared with gallotannic acid and sucrose for their effect on the cellulolytic, proteolytic, protein biosynthetic, and deaminative activities of rumen microorganisms. The inhibitory effects of carob pod extract upon the cellulolysis and deamination were correlated mainly with its sugar, rather than its tannin components. On the other hand, proteolytic activity and protein biosynthesis were more significantly affected by the tannin fraction. In contrast to the tannin fraction of carob pod extract, gallotannic acid inhibited cellulolytic activity. The harmful effect of a low concentration of tannins on protein biosynthesis could be prevented by the addition of carbohydrates to the reaction mixture. At high tannin concentration (40 mug/ml), however, the addition of carbohydrates did not prevent the inhibition. (+info)
THE ESTIMATION OF THE OXIDIZED AND REDUCED FORMS OF THE NICOTINAMIDE NUCLEOTIDES.
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1. A method is described for the determination of the oxidized and reduced forms of the nicotinamide nucleotides by measuring the rate of the oxygen uptake with an oxygen electrode in a system in which the nucleotide acts as the rate-limiting carrier in a cyclic system. 2. The method permits the measurement of quantities as low as 0.02mug. of NAD(+) or NADH or 0.01mug. of NADP(+) or NADPH. 3. The method permits the measurement of the nucleotides in extracts that contain non-specific reducing substances, coloured compounds or fluorescent materials, e.g. green leaves. 4. The results obtained by the present method are compared with those reported in the literature. (+info)
A STUDY ON THE GLUCOSAMINE-CONTAINING CONSTITUENTS OF THE SEEDS OF KIDNEY BEANS (PHASEOLUS VULGARIS).
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1. The constituents of the seeds of kidney beans containing glucosamine that could be released by acid hydrolysis (0.5 n-hydrochloric acid at 100 degrees ) were extracted into the phenol-rich phase on partitioning between phenol and water at 70 degrees . 2. These materials were also brought into solution on extracting the seeds with water (incomplete), or preferably with a slightly alkaline buffer in the absence of phenol. When these solutions were heated at 100 degrees or treated with trichloroacetic acid, all the materials containing acid labile glucosamine were carried down with the precipitate. Treatment with pepsin rendered the materials containing glucosamine soluble again. 3. All proteins in these extracts of kidney bean were found to be associated with various amounts of neutral and amino sugars by high-voltage electrophoresis and chromatography on Sephadex G-200 columns. 4. The isolation and crystallization of the main sugar components, d-glucosamine and d-mannose, are described and their significance in plant glycoproteins is discussed. (+info)
STUDIES ON THE EXTRACTION OF NITROGENOUS AND PHOSPHORUS-CONTAINING MATERIALS FROM THE SEEDS OF KIDNEY BEANS (PHASEOLUS VULGARIS).
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1. The conditions of extracting nitrogenous, phosphorus-containing and glucosamine-containing components of the seeds of kidney bean have been studied. 2. The dispersing of proteins was incomplete below pH 7, and the exact amount of protein extracted depended on the pH and the ionic strength of the solvent. 3. The extraction of proteins was practically complete in the range pH 7-9, but the relative amounts of the individual proteins obtained still depended on the pH of the extracting media, indicating a pH-dependent association-dissociation reaction between the protein molecules present. 4. The extraction of phosphorus-containing material showed an optimum at pH 6-7, and only a part of this was removed on dialysis. The precipitates obtained with trichloroacetic acid, on the other hand, retained very little phosphorus-containing material. 5. The significance of these findings is discussed. (+info)
STUDIES ON CARBOHYDRATE-METABOLIZING ENZYMES. THE HYDROLYSIS OF ALPHA-GLUCOSIDES, INCLUDING NIGEROSE, BY EXTRACTS OF ALFALFA AND OTHER HIGHER PLANTS.
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1. Enzyme preparations from 11 plant sources, from yeast and from the protozoan Tetrahymena pyriformis show nigerase activity, which, in most preparations, was 70-90% of that towards maltose. 2. These enzyme preparations also hydrolysed isomaltose, but there was a wide variation in relative maltase to isomaltase activity. 3. The maltase and nigerase activities of alfalfa and tomato preparations could not be differentiated by heat inactivation or inhibitor methods. However, with turanose used as a competitive inhibitor, evidence suggesting that maltose and nigerose are hydrolysed at different catalytically active sites in the alfalfa preparation was obtained. 4. It is probable that the alfalfa alpha-glucosidase exists as a mixture of isoenzymes. (+info)
ENZYME FORMATION IN HIGHER-PLANT TISSUES. DEVELOPMENT OF INVERTASE AND ASCORBATE-OXIDASE ACTIVITIES IN MATURE STORAGE TISSUE OF HELIANTHUS TUBEROSUS L.
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1. Washed aerated disks of mature tubers of H. tuberosus developed invertase and ascorbate-oxidase activities; this effect was not due to contaminating micro-organisms. 2. The use of specific inhibitors showed that such development was an expression of protein synthesis. 3. There was no visual evidence of cell division during induction of the enzymes. 4. The invertase could not be solubilized; most of the ascorbate oxidase was freely soluble. (+info)
CHANGES IN THE FREE NUCLEOTIDE PATTERN OF PEA SEEDS IN RELATION TO GERMINATION.
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1. Major changes in the free nucleotide and nucleoside pattern of germinating pea seeds are described. 2. During the imbibition phase of germination (0-16hr.) there was a 250% increase in ATP content and a parallel fall in AMP content without detectable change in ADP content. Metabolic implications are discussed. 3. The main nucleoside changes during imbibition were a 93% increase in xanthosine content and a 39% fall in adenosine content. 4. During the last phase of germination, leading to the emergence of the radicle, there is a general fall in free nucleotide content. AMP, ADP and ATP contents decreased 73, 48 and 52% respectively. Acetyl-3'-dephosphocoenzyme A concentration fell by 53%. However, the (NADP(+)+NADPH)/(NAD(+)+NADH) ratio increased, and except for uridine content (52% decrease) the nucleoside pattern changed little. 5. A sixfold increase in the concentration of an unidentified UDP-glycosyl compound occurs at this stage, although the content of UDP-glucose and UDP-galactose remained unchanged. 6. No free purine or pyrimidine bases could be detected at any stage of germination. (+info)