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1.
Specialized epidermal trichomes on the leaves of the epiphyte, Tillandsia paucifolia (Bromeliaceae) accumulate amino acids from solution. Simultaneous net uptake of 17 amino acids was determined using high performance liquid chromatography. Uptake occurs against concentration gradients at least as high as 104.  相似文献   
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3.
Infantile neuronal ceroid-lipofuscinosis (CLN1) is the form of neuronal ceroid-lipofuscinoses (NCL) with the earliest onset of symptoms. The locus of the most common form of these disorders, juvenile NCL (CLN3), has been mapped to chromosome 16. We report here linkage data of the same region in Finnish CLN1 families. Our results indicate that CLN1 is not allelic with CLN3 but represents a different locus, which is not located within about 70 cM in chromosome 16.  相似文献   
4.
Summary The relationship between proteins and the macroelements potassium, magnesium, calcium, sulphur and phosphorus was studied in homogenates of needles of different ages from Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.]. Complete extractions by acid digestion, protein extractions by a buffer-detergent and non-protein extractions by a buffer alone showed that most of the potassium and magnesium of the needles was soluble independent of the proteins. Only a minor part (50–60 ppm, dry weight) of the magnesium could be referred to the chlorophyll content of the needles. Both potassium and magnesium appeared independent of the protein gel filtration. This was also valid for the minor fraction of the total calcium content, which was extractable in a buffer. Heterogeneous calcium deposits are also suggested by extraction using a chelator (EGTA). Part of the buffer-soluble sulphur and phosphorus compounds occurred independently of solubilized proteins, and had complex distribution patterns after gel filtration, even outside the high molecular separation range. It is suggested that further analyses along the present lines, compared with conventional analyses on total extracts, may extend the usefulness of mineral nutrient analyses in plants.  相似文献   
5.
Fusion of terminally differentiated chick erythrocytes (CE) with replicating quail myoblasts or established L6J1 rat myoblasts results in reactivation of DNA synthesis in the dormant CE nuclei and in suppression of DNA synthesis in the myoblast nuclei. The nuclei of primary quail myoblasts are more effectively inhibited than the nuclei of established rat myoblasts. Inhibition of DNA replication occurs not only by preventing G1 nuclei from entering S-phase but also by blocking nuclei in S-phase and by delaying nuclei in G2 from undergoing mitosis and starting a new DNA replication cycle. No inhibition of DNA synthesis could be observed when mouse erythrocytes, i.e., erythrocytes lacking nuclei, were fused with rat myoblasts to generate mouse-globin-containing L6J1 cybrids. — Reactivation of CE nuclei is associated with a loss of the tissuespecific H5 histone variant. Complete elimination of H5 histone, however, does not seem to be a necessary prerequisite for the initiation or completion of DNA replication in CE nuclei since H5 antigens are found on reactivated G1, S, and G2 nuclei.  相似文献   
6.
Total DNAs from twelve natural isolates of Escherichia coli from animals and humans were examined by hybridization with a probe for IS1. Considerable variation in copy number was found. In the case of two strains isolated from the same individual, one strain contained no copies of IS1 and the other, much greater than 30. Evidence was also obtained for the existence of IS1-like elements (iso-IS1s) of greater than 15% sequence divergence relative to the IS1 from antibiotic resistance plasmid R100.  相似文献   
7.
Brita  Nyman 《Physiologia plantarum》1969,22(4):809-818
Biotin can not replace nonanal for Dipodascus aggregatus. The growth-promoting effect of nonanal (80 μW) remained unchanged when the concentration of biotin was increased from 2 μm per 1 to 200 μm per I. Oleic acid stimulated the growth of D. aggregates. However, unlike nonanal, oleic acid promoted growth even if cells from the exponential phase of growth were used as inoculum. The concentrations of oleic acid required to produce growth–stimulation were considerably higher than the concentrations of nonanal required to promote growth. The growth-stimulating effect f nonanal seems to be different from t he effect of oleic acid. The incorporation of 1C-ghtCOM by D. aggregates was stimulated by the addition of nonanal (80μm) to the growth medium. The uptake of glucosamine was not affected by nonanal (80 or 160 μM in the presence of ethanol, 0.8 to 100μ in the absence of ethanol). Hexokinase activity in cell-free homogenates was not affected by the addition of nonanal over a concentration range from 0.0059 to 1250μM.  相似文献   
8.
Nyman B 《Physiologia plantarum》1969,22(6):1322-1328
The growth of Dipodascus aggregatus in cultures inoculated with cells from the acceleration phase of growth was stimulated by the saturated and unbranched aliphatic C(3) C(4) , and C(6) to C(11) aldehydes (80 μM]. Nonanal was most active in stimulating growth. The C(12) aldehyde inhibited growth. The C(5) , aldehyde generally inhibited growth. - Nonan did not affect growth. 2-Nonanone and 5-nonanone promoted growth insignificantly. - In cultures inoculated with cells from the exponential phase growth was unaffected or even inhibited by all the aldehydes tested. The C(4) , C(5) , C(10) , and C(11) aldehydes inhibited growth to a larger extent than nonanal.  相似文献   
9.
The role of endogenous benzodiazepine receptor ligands in the pathogenesis of hepatic encephalopathy was studied in humans and in rat models of hepatic encephalopathy. Endogenous benzodiazepine ligands were extracted from rat brain and human CSF by acid treatment and purification by HPLC. Detection and partial characterization of these endogenous benzodiazepine ligands were carried out using both radioreceptor binding assays and radioimmunoassays with anti-benzodiazepine antibodies. Four different benzodiazepine receptor ligands were identified in human and rat tissue, two of which may be diazepam and desmethyldiazepam, based on elution profiles and anti-benzo-diazepine antibody reactivity. Human CSF and serum from patients with hepatic encephalopathy contained approximately 10 times more endogenous benzodiazepine receptor ligand than CSF from controls or nonencephalopathic patients with liver disease. The levels of brain benzodiazepine receptor ligand compounds were also increased approximately 10-fold in rats suffering from fulminant hepatic failure, but not in rats with portacaval shunts, a model of chronic hepatic disease. The increased concentrations of these substances could be behaviorally significant and may contribute to the pathogenesis of hepatic encephalopathy.  相似文献   
10.
Endothelin-1 stimulates its own synthesis in human endothelial cells.   总被引:4,自引:0,他引:4  
We studied whether endothelin-1 (ET-1) would affect its own synthesis. Human umbilical cord vein endothelial cells in methionine-poor culture medium containing [35S] methionine were treated with synthetic ET-1 or ET-3. Immunoprecipitation of 35 S-labeled ET-1 was performed with rabbit ET-1 antiserum. ET-1 caused an 40 +/- 4% (mean +/- SEM) increase of immunoprecipitable 35 S-labeled ET-1 as confirmed by its elution point in reversed phase high power liquid chromatography (HPLC). ET-3 caused a 23 +/- 2% increase in ET-1 concentration. Amplification of cDNA by PCR showed both ET-1 and ETB receptor mRNAs in human cord vein endothelial cells. We conclude that ET-1 increases its own synthesis in endothelial cells. This suggests a positive autocrine feed-back action of ET-1 on its own synthesis, an effect which is probably mediated by non-specific ETB receptors.  相似文献   
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