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31.
The status and transfer of metals across the rat placenta were studied by subcellular and molecular fractionations of this organ at 2 and 24 h after iv injection of radiolabeled metals. The soluble and nuclear fractions showed higher contents of copper and zinc, whereas most of the nickel was associated with the soluble fraction. Cadmium was almost evenly distributed between the microsomal and nuclear fractions. Gel filtration of the soluble fractions showed nickel associated with an unknown low molecular weight form; zinc with high molecular weight proteins; copper with metallothionein, ceruloplasmin, and high molecular weight proteins; and cadmium with high molecular weight proteins and metallothionein. 相似文献
32.
Effects of the administration of cadmium and zinc on the concentration of zinc in the thymus of rats
Paloma Huerta Paloma Galan Alberto J. Alcala Bartolome Ribas Jose M. Teijon 《Biological trace element research》1988,18(1):95-103
The zinc content of thymus glands of male Wistar rats has been determined during five weeks of treatment with ZnCl2 and CdCl2, and compared with a group of control rats. THymus gland extracts were chromatographed on columns of Sephadex G-75 and the zinc content of the one hundred fractions obtained were determined by atomic absorption spectrophotometry. The rats treated with ZnCl2 showed an increase in the thymus concentration of zinc bound to high and low molecular weight proteins. The rats treated with CdCl2 showed an increase in zinc concentration, as opposed to the control group, during the first three weeks of treatment, and thereafter show a toxic effect of cadmium on the gland, with ulterior regression of the latter, and a decrease in the concentration of zinc. 相似文献
33.
Alberto Abbruzzese 《Journal of neurochemistry》1988,50(3):695-699
Deoxyhypusine hydroxylase catalyzes the formation of hypusine from deoxyhypusine in a precursor form of eukaryotic initiation factor 4D (eIF-4D). The enzymatic activity was examined in mammalian brain homogenates and the results were consistent with the existence of deoxyhypusine hydroxylase levels comparable to those occurring in other mammalian tissues. Interspecies differences in the enzyme distribution were quite limited, with the highest specific activity values observed in cow brain (1.82 units/ mg of protein). In the rat the enzyme was found to be unevenly distributed among various brain regions. The parietal cortex contained the highest specific activity (2.1 units/mg of protein). Rat brain deoxyhypusine hydroxylase was mainly present in the postmicrosomal supernatant (81% of the total activity). The highest specific activity (3 units/mg of protein) was observed in the rat brain during the first few days of life. Thereafter the activity started to decline, and continued to do so for 15 days, remaining throughout the rest of life at levels of less than one-half that of newborn. 相似文献
34.
Reggiani Remo; Cantu Carlo Alberto; Brambilla Ida; Bertani Alcide 《Plant & cell physiology》1988,29(6):981-987
In excised rice roots, anaerobic degradation of proteins gaverise to an increase of free-amino acids. Anoxic accumulationof alanine, -aminobutyric acid and proline was the consequenceof the interconversion of glutamate, aspartate and amides. Theshift in the composition of the amino acid pool appears to becaused by changes in keto acid levels. The role of reactionsinvolved in amino acid interconversion and the physiologicalsignificance of these interconversions are considered and discussed. (Received November 25, 1988; Accepted June 9, 1988) 相似文献
35.
Dr. M. Angustias Rivadeneyra Inmaculada Pérez-García Alberto Ramos-Cormenzana 《Current microbiology》1992,24(6):343-347
Struvite precipitation by 161 bacterial strains isolated from soil and fresh water was analyzed. The results showed that the ability to form struvite is not widespread among these bacteria. Struvite precipitation was influenced by environmental factors and could be enhanced by changing the experimental conditions. There was no clear relationship between the taxonomic status of a given strain and its ability to precipitate struvite. However, bacteria of the genusPseudomonas showed a greater tendency to precipitate struvite than organisms of the remaining genera studied, and five new genera were identified as struvite producers. 相似文献
36.
Silvio De Flora Francesco D'Agostini Alberto Izzotti Roumen Balansky 《Mutation research》1991,250(1-2):87-93
The daily i.t. administration of benzo[a]pyrene (BP) to Sprague-Dawley rats, for 3 consecutive days, did not cause any toxicity or clastogenicity in bone marrow cells, as evaluated by monitoring the ratio of polychromatic to normochromatic erythrocytes and the frequency of micronucleated polychromatic erythrocytes. However, BP produced a considerable enhancement of binucleated and micronucleated pulmonary alveolar macrophages, as well as a significant increase in polymorphonucleates recovered by bronchoalveolar lavage. These effects were prevented by administering the thiol N-acetylcysteine (NAC) by gavage 5 h before each BP instillation. In addition, the i.t. treatment with BP resulted in the formation of BP diolepoxide (BPDE)-DNA adducts in lungs and liver, as assessed by synchronous fluorescence spectrophotometry, with fluorescence peaks of similar magnitude in the 2 tissues. Pretreatment with NAC by gavage completely prevented BPDE adducts to liver DNA and significantly decreased those to lung DNA. 相似文献
37.
Rosa Sorrentino Carlo Iannicola Sandro Costanzi Alberto Chersi Roberto Tosi 《Immunogenetics》1991,33(2):118-123
DNA molecules derived from three alleles of the HLA-DRB3 locus and differing from each other at several nucleotide sites were denatured and cross-hybridized. Each allelic combination was found to generate a pair of heteroduplexes of different mobility. Their retardation as compared to homoduplexes was proportional to the number of mismatches. In each heteroduplexes pair the component possessing the highest number of Pyr-Pyr oppositions was the most retarded. The results are those predicted by a theoretical model implying a correlation between base-pair opening and bending of the DNA double helix. These observations introduce a new HLA typing method at the genomic level and indicate an experimental approach to the analysis of the superhelical DNA conformation as related to different types of base oppositions. 相似文献
38.
Summary Previous studies examining the regulation of the synthesis of G6PDH and 6PGDH in rat liver and adipose tissue have focused on the induction of these enzymes by different diets and some hormones. In rat liver these enzymatic activities seem to be regulated by a mechanism involving changes in the NADPH requirements. In this paper we have studied the effect of changes in the flux through different NADPH-consuming pathways on G6PDH and 6PGDH levels in adipose tissue and on the NADPH/NADP ratio. The results show that: I) an increase in the consumption of NADPH, caused by the activation of either fatty acid synthesis or detoxification systems which consume NADPH, is paralleled by an increase in the levels of these enzymes; II) when the increase in consumption of NADPH is prevented, the G6PDH and 6PGDH levels do not change.Abbreviations G6PDH
Glucose-6-Phosphate Dehydrogenase
- 6PGDH
6-Phosphogluconate Dehydrogenase
- GR
Glutathione Reductase
- ME
Malic Enzyme
- tBHP
t-Butyl Hydroperoxide
- NF
Nitrofurantoin
- CumOOH
Cumene Hydroperoxide 相似文献
39.
Luigi D. Notarangelo Ornella Parolini Fulvio Porta Franco Locatelli Arnalda Lanfranchi Massimo Marconi Luigi Nespoli Alberto Albertini Ian W. Craig Alberto G. Ugazio 《Human genetics》1991,88(2):237-241
Summary We report on a thrombocytopenic female belonging to a pedigree with the Wiskott-Aldrich syndrome (WAS). Restriction fragment length polymorphism (RFLP) analysis with probe M27, closely linked to the WAS gene, demonstrated that she is a carrier of WAS. Both small-sized and normal-sized platelets were present, suggesting that, unlike the vast majority of WAS carriers, she does not manifest nonrandom X-chromosome inactivation in the thrombopoietic cell lineage. Study of X-chromosome inactivation by means of RFLP and methylation analysis demonstrated that the pattern of X-chromosome inactivation was nonrandom in T lymphocytes, but random in granulocytes. While this is the first complete report on the occurrence of thrombocytopenia in a carrier female of WAS as the result of atypical lyonization, it also suggests that expression of the WAS gene occurs at (or extends up to) a later stage than the multipotent stem cell along the hematopoietic differentiation pathway. 相似文献
40.
Quantitative Immunologic Analysis of the Methanogenic Flora of Digestors Reveals a Considerable Diversity 总被引:9,自引:8,他引:1
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To determine which methanogens occur in digestors, we performed a quantitative immunologic analysis of a variety of samples. A comprehensive panel of calibrated polyclonal antibody probes of predefined specificity spectra was used. This allowed precise identification of bacteria by antigenic fingerprinting. A considerable diversity of methanogens was uncovered, much larger than previously reported, encompassing at least 14 strains of 11 species. Strategies were developed to measure the load of any given methanogen in a sample and to compare samples quantitatively. Two methanogens were found to predominate which were antigenically closely related with either Methanobacterium formicicum MF or Methanobrevibacter arboriphilus AZ. Fundamental data, probes, and methods are now available to monitor methanogenic subpopulations during digestor operation and thus learn about their respective roles and predictive significance. 相似文献