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51.
M. L. Delorme J. Denis B. Nordlinger M. Boschat P. Opolon 《Journal of neurochemistry》1981,36(3):1058-1066
Experimental acute liver ischemia in pigs induces an increment in plasma free tryptophan with decreased total tryptophan. Brain tryptophan is elevated in all brain areas. A slight, but significant increase of brain serotonin is demonstrated in the striatum only, while 5-HIAA (5-hydroxyindoleacetic acid) is significantly lower in the hypothalamus. Other brain areas do not show significant changes in serotonin and 5-HIAA levels. Neither the high plasma free tryptophan levels, nor the decreased sum of neutral competitive amino acids are consistent with such an elevation of brain tryptophan. Hemodialysis was carried out with two different kinds of membranes: cuprophan (with an efficient removal of molecules up to molecular weight 1300) and AN 69 polyacrylonitrile (efficient removal up to 15,000). Ammonia and aminoacid clearance are similar for both membranes. After AN 69, plasmatic free tryptophan and brain tryptophan are lower than after liver devascularization, but still higher than normal. Serotonin significantly increases in the cortex, midbrain and hypothalamus without concomitant rise of 5-HIAA levels. After cuprophan hemodialysis, plasma total tryptophan is lower than in normal and even comatose animals, whereas free tryptophan is normal. Intracerebral tryptophan is similar to AN 69 dialysed animals, but in the hypothalamus it is similar to nondialysed animals. Brain serotonin levels are not modified. 5-HIAA decreases in the hypothalamus. This finding suggests that middle molecules (which are not cleared out with cuprophan hemodialysis) are involved in the intracerebral transfer of tryptophan and the metabolism of serotonin, mainly in the hypothalamus. 相似文献
52.
Abstract: Fractions of neurospecific S-100 protein were purified from bovine brain and their physicochemical properties were studied. Conformational changes caused by the binding of calcium to S-100 protein fractions were detected by means of differential and fluorescence spectroscopy. Fractions demonstrating opposite shifts of their spectra also differ in the distribution in double-phase system. The number of calcium-binding centers and their association constants were determined by means of equilibrium dialysis and gel filtration. The nature of the differences in the interaction of various S-100 protein fractions with calcium is discussed. 相似文献
53.
John L. Sternick Elizabeth M. Allen Linda M. Ripani Denis J. Schrier Vernon L. Moore 《Cellular immunology》1981,65(2):211-220
When C57BL/6 mice were injected iv with BCG in an oil-in-saline emulsion, they developed intense pulmonary granulomatous inflammation (PGI) and splenomegaly as well as chemotactic activity for macrophages and angiotensin-converting enzyme (ACE) in their lung fluids. PGI, splenomegaly, and levels of chemotactic activity and ACE were markedly reduced in T-cell-deficient “B” mice. The capacity to develop PGI was fully restored and splenomegaly was partially restored in “B” mice by the provision of syngeneic thymocytes, spleen cells, or purified T cells. These results indicate that the full expression of BCG-induced PGI is dependent upon thymus-derived cells and is associated with high levels of chemotactic activity for macrophages and ACE in the lung lavage fluid. Although BCG-induced splenomegaly appears to be T cell dependent, it did not reach its full magnitude in reconstituted “B” mice. 相似文献
54.
Production of Aseptic Spores of Vesicular-Arbuscular Endophytes and Their Viability After Chemical and Physical Stress 总被引:4,自引:1,他引:3 下载免费PDF全文
The survival of germinating spores of vesicular-arbuscular endophytes after treatments with oxidizing agents, antibiotics, moist heat, ultrasonic radiation, and ultraviolet radiation was compared with that of their contaminating microbes. Spores of three species were rapidly decontaminated by treatment with 0.42% (wt/vol) chlorine available from 5.0% (wt/vol) chloramine-T at 30°C for 20 to 40 min depending on the species and the soil from which they were extracted. This treatment did not change spore viability. The survival of spores was reduced by exposure for 20 min to 1.11% chlorine at 30°C for Glomus caledonius or at 35°C for Acaulospora laevis. Growth of any bacteria surviving treatment with oxidizing agents was inhibited by 100 μg of chloramphenicol per ml in agar; however, spore germination and germ tube growth were reduced only by concentrations greater than 200 μg/ml in agar. Spore germination was decreased by concentration of pimaracin, which controlled fungal growth. The spores survived moist heat at 40°C for 80 min, 55°C for 10 min, and 60°C for less than 1 min. The viability of spores was unaffected by ultrasonic irradiation for up to 4 min. Spores of G. caledonius and A. laevis were extremely resistant to ultraviolet radiation. Their viability was unaffected by exposure to 5 × 108 ergs cm−2 from an ultraviolet source of 253.7nm. The spores had very thick, pigmented walls, and the possibility that these provided some protection against the physical and chemical treatments is discussed. The degree of physiological damage to the spores caused by the treatments demonstrated some adverse effects of basic laboratory procedures. This information, together with that on the comparative sensitivity of contaminating microbes to the treatments, was used in the development of protocol for producing large numbers of uncontaminated spores. 相似文献
55.
Tomáš Trnka Miloslav Černý Anna Ya. Shmyrina Alexander S. Shashkov Alexander F. Sviridov Oleg S. Chizhov 《Carbohydrate research》1979,76(1):39-44
13C-N.m.r. spectra of all possible 1,6:2,3- and 1,6:3,4-dianhydro-β-D-hexo-pyranoses and their O-acetyl and deoxy derivatives are presented. Relations between chemical shifts of certain carbon atoms and the structure of the dianhydrides are outlined, and their application in structural analysis is discussed. Inversion of configuration of the oxirane ring from the endo to the exo position is associated with typical upfield-shifts for oxirane-ring carbon atoms C-2 or C-4, respectively. Possible inter-relationships between 13C-chemical shifts and steric and polar interactions in the dianhydro derivatives are discussed. 相似文献
56.
Denis J. Miller Herbert Kleber Joseph R. Bloomer 《The Yale journal of biology and medicine》1979,52(1):135-140
One hundred and seventy-seven former heroin addicts, consisting of 85 who were newly admitted to a methadone maintenance program and 92 who had received methadone for a mean period of 30 months, were prospectively studied for up to 2 years in order to determine: (1) the effect of heroin withdrawal on the hepatic abnormalities, and (2) the incidence of HBsAg, anti-HBs, and anti-HCc as indices of the frequency of hepatitis B virus infection. Our study indicates that (1) hepatic abnormalities persist when heroin is discontinued and are not temporally related to drug and/or needle usage, and (2) that 71% of subjects had either HBsAg or anti-HBs; anti-HBc was tested for in 16 patients and was present in 100%, although 9 of the 16 were both HBsAg- and anti-HBs-negative. This study suggests that hepatitis B is largely responsible for the liver dysfunction. It is proposed that an abnormality in immune function, induced by heroin, is responsible for the high incidence of chronic hepatitis. Attention is drawn to the similarity between former drug addicts and hemophiliacs, since both develop chronic hepatitis in spite of anti-HBs in the serum. 相似文献
57.
Biochemical research on oogenesis. RNA accumulation during oogenesis of the dogfish Scyliorhinus caniculus 总被引:2,自引:0,他引:2
Four biochemical mechanisms have been shown to operate in the oocytes of amphibians and teleosts: (1) amplification of the 28 S and 18 S genes, (2) noncoordinate accumulation of 5 S RNA and 28 S + 18 S RNA, (3) storage of 5 S and transfer RNA made in excess by small oocytes within nucleoprotein particles, (4) expression of different 5 S genes in oocytes and somatic cells. We have tried to extend these observations to another group of vertebrates, i.e., selacians (Chondrichthya). Our data suggest that ribosomal gene amplification is low or absent in the oocytes of the dogfish Scyliorhinus caniculus. However, previtellogenic oocytes of this species accumulate more 5 S RNA than needed for ribosome assembly. Transfer and 5 S RNA present in small oocytes are probably not free in the cell sap. A substantial fraction of these RNAs sediments at 10 S when homogenates of immature ovaries are centrifuged in sucrose density gradients. In contrast to what we observed in amphibians and teleosts, 5 S RNA from ovaries of S. caniculus is identical in sequence to 5 S RNA from liver. Among the four mechanisms mentioned above, the second and probably the third one are used by the oocytes of S. caniculus. Mechanism (4) is absent in this species. No definitive conclusion can be drawn concerning mechanism (1), i.e., ribosomal gene amplification. 相似文献
58.
Denis A. Magoffin Gregory F. Erickson 《In vitro cellular & developmental biology. Plant》1988,24(9):862-870
Summary Although luteinizing hormone (LH) alone stimulates ovarian interstitial cells cultured in serum-free medium to synthesize
large amounts of androgens, there seem to be additional factors in vivo that modulate the time course and magnitude of the
cellular responses to LH. In an attempt to develop a more nearly physiologic cell culture model, lipoproteins, insulin, and
insulinlike growth factor-I (IGF-I) were added to the serum-free medium. The effects of these modifications on androgen biosynthesis
by dispersed cells from ovaries of hypophysectomized immature rats cultured in 96-well tissue culture plates were examined.
A saturating dose of LH stimulated a 25-fold increase in androsterone synthesis at 2 d, which decreased at 4 and 6 d. Addition
of human high density (hHDL) or human low density lipoprotein (hLDL) caused a 2.5-fold increase in LH-stimulated androsterone
synthesis. Cells were approximately twice as sensitive to hHDL (ED50=5.5±0.5 μg cholesterol/ml) compared to hLDL (ED50=9.1±1.1 μg cholesterol/ml). Surprisingly, rat HDL caused only a 40% increase in LH-stimulated androsterone synthesis. When
insulin alone was added to cells cultured with a saturating dose of LH, there was a 2.8-fold increase in androsterone synthesis.
Addition of hHDL and insulin together caused a synergistic increase in LH-stimulated androsterone synthesis. In contrast to
hHDL, which did not change the time course of LH-stimulated androsterone production, insulin prolonged maximal LH-stimulated
androsterone synthesis at 4 and 6 d. Inasmuch as the ED50 for insulin action (1.3±0.1 μg/ml) was supraphysiologic, the effects of IGF-I on LH-stimulated androgen synthesis were examined.
IGF-I mimicked all of the effects of insulin, but at a physiologic concentration (ED50=2.5±0.3 ng/ml). Ovarian cells cultured in serum-free medium supplemented with hHDL and insulin or IGF-I exhibit responses
that closely approximate the physiologic responses observed in vivo. These results suggest that lipoproteins and IGF-I are
important physiologic stimulators of ovarian theca-interstitial cell androgen biosynthesis which, when added to the serum-free
medium, make the cellular responses in this in vitro model more nearly approximate the responses in vivo.
This research was supported by research center grant HD 12303 from the National Institute of Child Health and Human Development,
Bethesda, MD, and USCD Academic Senate grant RM-169M 相似文献
59.
The HOX-5 and surfeit gene clusters are linked in the proximal portion of mouse chromosome 2 总被引:1,自引:0,他引:1
Lisa Stubbs Clare Huxley Brigid Hogan Timothy Evans Mike Fried Denis Duboule Hans Lehrach 《Genomics》1990,6(4)
Using an interspecies backcross, we have mapped the HOX-5 and surfeit (surf) gene clusters within the proximal portion of mouse chromosome 2. While the HOX-5 cluster of homeobox-containing genes has been localized to chromosome 2, bands C3-E1, by in situ hybridization, its more precise position relative to the genes and cloned markers of chromosome 2 was not known. Surfeit, a tight cluster of at least six highly conserved “housekeeping” genes, has not been previously mapped in mouse, but has been localized to human chromosome 9q, a region of the human genome with strong homology to proximal mouse chromosome 2. The data presented here place HOX-5 in the vicinity of the closely linked set of developmental mutations rachiterata, lethargic, and fidget and place surf close to the proto-oncogene Abl, near the centromere of chromosome 2. 相似文献
60.
Denis Faure Jos Desair Veerle Keijers My Ali Bekri Paul Proost Bernard Henrissat Jos Vanderleyden 《Journal of bacteriology》1999,181(10):3003-3009
The rhizosphere nitrogen-fixing bacterium Azospirillum irakense KBC1 is able to grow on pectin and beta-glucosides such as cellobiose, arbutin, and salicin. Two adjacent genes, salA and salB, conferring beta-glucosidase activity to Escherichia coli, have been identified in a cosmid library of A. irakense DNA. The SalA and SalB enzymes preferentially hydrolyzed aryl beta-glucosides. A Delta(salA-salB) A. irakense mutant was not able to grow on salicin but could still utilize arbutin, cellobiose, and glucose for growth. This mutant could be complemented by either salA or salB, suggesting functional redundancy of these genes in salicin utilization. In contrast to this functional homology, the SalA and SalB proteins, members of family 3 of the glycosyl hydrolases, show a low degree of amino acid similarity. Unlike SalA, the SalB protein exhibits an atypical truncated C-terminal region. We propose that SalA and SalB are representatives of the AB and AB' subfamilies, respectively, in glycosyl hydrolase family 3. This is the first genetic implication of this beta-glucosidase family in the utilization of beta-glucosides for microbial growth. 相似文献