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991.
Virus removal during groundwater recharge: effects of infiltration rate on adsorption of poliovirus to soil. 总被引:3,自引:3,他引:0 下载免费PDF全文
Studies were conducted to determine the influence of infiltration rate on poliovirus removal during groundwater recharge with tertiary-treated wastewater effluents. Experiments were conducted at a uniquely designed, field-situated test recharge basin facility through which some 62,000 m3 of sewage had been previously applied. Recharge at high infiltration rates (75 to 100 cm/h) resulted in the movement of considerable numbers of seeded poliovirus to the groundwater. Moderately reduced infiltration rates (6 cm/h) affected significantly improved virus removal. Very low infiltration rates (0.5 to 1.0 cm/h), achieved by partial clogging of the test basin, yielded the greatest virus removal efficiencies. 相似文献
992.
Fumito Matsuura Roger A. Laine Margaret Z. Jones 《Archives of biochemistry and biophysics》1981,211(1):485-493
Two oligosaccharides accumulate in the kidney of a goat with β-mannosidosis. These oligosaccharides were isolated and purified from kidney extracts by Bio-Gel P2 gel permeation column chromatography. Their structures were characterized as Manβ1 → 4GlcNAc and Manβ1 → 4G1cNAcβ1 → 4G1cNAc by mass spectrometry of the permethylated intact oligosaccharide alcohols and permethylated native oligosaccharides. Carbohydrate composition analysis, methylation linkage studies, and enzymatic hydrolysis were also performed. Stored in 1 g of kidney were 1.6 μmol of disaccharide and 7.6 μmol of trisaccharide, which was three times that found in the brain of this affected animal (M. Z. Jones and R. A. Laine, 1981, J. Biol. Chem., 256, 5181–5184). In both the brain and kidney of the affected goat, oligosaccharide accumulation was evidently represented by membrane-bound, electron-lucent vacuoles in numerous cell types. While lesions in the brain were associated with profound neurological deficits, functional impairment of the kidney was not apparent. Similar oligosaccharides excreted in urine may be derived from those stored in the kidney. The mass spectrometric methods utilized in this investigation will facilitate comparison of oligosaccharide composition in different tissues and biological samples in β-mannosidosis and other disorders of glycoprotein catabolism. 相似文献
993.
1. The role of tocopherols in tomato chloroplasts from fresh, cold and dark-stored as well as stored and illuminated leaves was studied.2. The cold and dark storage of leaves results in a loss of chloroplast α- and γ-tocopherols of about 30–40% accompanied by an increase in chloroplast δ-tocopherol of about 40%. On illumination of stored leaves, an elevation of α- and γ-tocopherol level to about 110 and 95% of the control, respectively, occurs, whilst δ-tocopherol content is not affected.3. Experiments performed with 2,2-diphenyl-1-picrylhydrazyl-treated chloroplasts show that only about 70% of total α-tocopherol is functionally active in the electron transport of Photosystem II between the diphenyl-carbazide (DPC) donation site and the inhibition site of DBMIB.4. A small amount of α-tocopherol quinone (about 10% of α-tocopherol content) is found in chloroplasts from fresh, fresh and illuminated as well as cold and dark-stored tomato leaves, whereas the illumination of the latter increases the chloroplast α-tocopherol quinone content 3-fold. Moreover, following the illumination of chloroplasts from cold and dark-stored as well as stored and illuminated leaves, the oxidation of exogenous α-tocopherol to α-tocopherol quinone is 2-fold faster then in chloroplasts from fresh leaves.5. The primary product (‘α-tocopheroxide’) formed during the α-tocopherol oxidation by illuminated chloroplasts was identified as 8a-hydroxy-α-tocopheron.6. Exogenous α-tocopherol inhibits the lipid photoperoxidation by about 40–50% in chloroplasts from all three kinds of tomato leaf.7. The results seem to suggest that chloroplast α-tocopherol is involved in both electron transport of PS II and antioxidizing system of chloroplasts. 相似文献
994.
The regions of B6K DNA corresponding to oriT, finO and traS are mapped using a number of hybrid plasmids and deletion mutants pAS3::Tn5, pAS3::Tn7 and pAS3::Tn9 obtained in vitro after treatment with restriction endonucleases EcoRI and BamHI. FinO- and traS-like genes were mapped in the regions of 10 and 25,0-25,4 MD, respectively, oriT being situated in the region of 4,6-4,7 Md. 相似文献
995.
Cultivation ofAspergillus niger 97A in baffled flasks on a shaker brings about metabolic changes demonstrated in increased citric acid biosynthesis, morphological
changes and alterations in the mycelial cell wall. 相似文献
996.
Apyrase (ATP-diphosphohydrolase, EC 3.6.1.5) and inorganic pyrophosphatase (EC 3.6.1.1) were partially purified fromS. aureofaciens RIA 57 and characterized. Apyrase degrades, in addition to ATP, other nucleoside triphosphates and nucleoside diphosphates,
diphosphate, thiamine diphosphate, phosphoenolpyruvate and oligophosphates of chain lengthn ≦ 90. The apyrase activity was detected in the membrane and supernatant fractions. Its properties (substrate specificity, effect
of inhibitors, pH optimum and effect of Mg2+ ions) were similar in both fractions except for the effect of oligomycin that inhibited only the membrane fraction. Pyrophosphatase
exhibited a strict substrate specificity, substrates other than diphosphate being degraded relatively slowly. Of other enzymes
exhibiting the phosphatase activity acid phosphatase (EC 3.1.3.2) and alkaline phosphatase (EC 3.1.3.1), trimetaphosphatase
(EC 3.6.1.2) and exopolyphosphatase (EC 3.6.1.11) degrading oligophosphates of chain lengthn = 15, 40 and 60, were detected. 相似文献
997.
Preferential feeding behaviour by Daphnia magna was shown when Daphnia were fed on a mixture of 14C-labelled algae (Chlorella vulgaris or Scenedesmus quadricauda) and 3H-labelled bacteria (Escherichia coli). Daphnia consumption of bacteria was equal or higher in the presence of algae. On the other hand, in the presence of bacteria, algal consumption decreased by 40–70% compared to algal consumption in the absence of bacteria. 14C radioactive uptake was in good agreement with the chlorophyll content and demonstrates the preferential feeding behaviour of Daphnia. 相似文献
998.
Effect of interferon on phospholipid methylation by peripheral blood mononuclear cells 总被引:1,自引:0,他引:1
The effect of human interferon (IFN) preparations on the metabolic pathway leading to the synthesis of phosphatidylcholine (PC) by a stepwise addition of methyl groups to phosphatidylethanolamine (PE) was investigated in human peripheral blood mononuclear (PBMN) cells. An inhibition of the synthesis of PC via this pathway was regularly observed with both alpha- (recombinant or natural) and beta-IFN. This inhibition was apparent within the first 5 min of treatment, reached its maximum between 15 min and 1 hr, and persisted at the same level until 6 hr, the last time point examined. Each of the transmethylated products of PE underwent a similar inhibition, as measured by the turnover rate of individual products. The intracellular pool of the methyl donors, methionine and S-adenosyl-methionine (SAM), was shown to be unaffected. The methyltransferase activity of IFN-pretreated cell extracts was unchanged. These findings support the hypothesis that IFN induces a functional change in phospholipid methylation at the level of organized membrane-bound phospholipid methyltransferase enzymes in intact cells. 相似文献
999.
The distribution of small negative ions with mobility kr=0.5+ (cm2/Vs) in an air conditioned room is presented. The air was ionized by an ion generator, which was placed at the outlet of the air duct. The measurements were made at 100 different locations in the room. It was established, that the main factors in the distribution of ions were the coordinates of points in the room space. Regression analysis method was applied to determine optimal estimate of identified static characteristics of ions distribution. The main purpose of this research was to obtain data for the correct placement of ion generators in air conditioned or ventilated rooms. 相似文献
1000.
Acetohydroxy acid synthase is a target for leucine containing peptide toxicity in Escherichia coli. 总被引:5,自引:3,他引:2 下载免费PDF全文
Acetohydroxy acid synthase from a mutant resistant to leucine-containing peptides was insensitive to leucine inhibition. It is concluded that acetohydroxy acid synthase is a target for the toxicity of the high concentrations of leucine brought into Escherichia coli K-12 by leucine-containing peptides. 相似文献