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11.
Helmut Segner Roland Marthaler Michael Linnenbach 《Environmental Biology of Fishes》1988,21(2):153-159
Synopsis Young (7–10 days after hatching) brown trout (Salmo trutta) exposed for 5 days to pH 5 in high calcium water and at 2 temperatures (12°, 4°C) in the laboratory displayed no alterations
in growth or in mucous cell concentration and volume, compared to the control group kept at pH 7.2. Contamination of acid-stressed
young with 230 μg All-1 resulted in significant growth depression and Al accumulation, but in no changes of mucous cell morphometrics. Field tests
in low calcium water produced high mortality at low pH (5.1), but showed consistent effects on mucous cells as in laboratory
experiments. Three-month-old juveniles of brown trout, subjected to decreased pH values at 12° and in high calcium water for
8 days exhibited mucous cell hyperplasia (without hypertrophy) within 3 h of the acid addition. After 120 h sloughing of the
integument occurred with full recovery not possible within a 4-day-recovery period. Although the results presently apply only
to hard water conditions, the differences between juveniles and recently hatched young in tolerance to pH- and Al-mediated
stress may also be of importance for soft waters affected by acid rain. 相似文献
12.
Tetanus Toxin and Botulinum A and C Neurotoxins Inhibit Noradrenaline Release from Cultured Mouse Brain 总被引:4,自引:3,他引:1
The specific binding protein for substance P (SP) was solubilized in an active form from the crude mitochondrial (P2) fraction of bovine brainstem. After incubation with 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS) and 0.1 M NaCl at 0 degrees C for 30 min, the SP binding to the supernatant fraction (100,000 g, 60 min) was determined by the glass fiber filtration method reported by Bruns et al. (1983). The specific [3H]SP binding to the solubilized fraction was highly specific for SP and was displaced by nanomolar concentrations of SP and physalaemin, but only by micromolar concentrations of eledoisin. In addition, the binding was inhibited by GTP (approximately 40% of the specific binding decreased by 10 microM GTP) in both preparations. These results were virtually identical to those of P2 membrane preparations and suggested that this high-affinity SP binding site belongs to the SP-P type. Scatchard analyses of SP binding to the solubilized fraction revealed a single saturable component with a Bmax of 22.0 +/- 5.10 fmol/mg protein and a KD of 0.79 nM, and these values are almost the same as those obtained in the P2 fraction (Bmax = 31.3 +/- 3.56 fmol/mg protein, KD = 0.82 nM). Gel filtration analysis showed that the detergent-SP binding protein complex has two calculated molecular weights of greater than 1,000,000 and 55,000-60,000 (a corresponding Stokes radius of 35.5 nm). 相似文献
13.
14.
Besides Clostridium thermoaceticum and C. formicoaceticum other resting acetogenic clostridia such as C. aceticum and C. thermoautotrophicum and to a lesser extent non-clostridial acetogens such as Butyribacterium methylotrophicum and Eubacterium limosum were able to reduce propionate to propanol at the expense of carbon monoxide or formate. Methylviologen usually increased the reduction rate. Ten M molybdate in the growth medium decreased this capability for C. thermoaceticum but increased it or had no effect for the other organisms. Ten M tungstate in the growth medium increased the aldehyde oxidoreductase activity in all organisms. Crude extracts of C. thermoaceticum cells grown in the presence of 10 M or 1 mM molybdate showed by ELISA the same or even a 4 fold concentration of aldehyde oxidoreductase in the latter case. However, the enzymic activity was very low in both cases. Omission of dithionite in the growth medium diminished the antigen by a factor of about 8. The immunological distance between the enzyme from C. thermoaceticum and C. thermoautotrophicum was rather low but very large to C. formicoaceticum and undeterminably large to the other organisms.Abbreviations Ald-DH
aldehyde dehydrogenase
- AOR
aldehyde oxidoreductase
- CO-DH
carbon-monoxide dehydrogenase
- ELI-SA
enzyme-linked immunosorbent assay
- FDH
formate dehydrogenase
- MV
methylviologen
- V++
oxidised
- V+.
reduced viologen 相似文献
15.
Helmut Bäumlein Istvan Nagy† Raimundo Villarroel Dirk Inzé Ulrich Wobus 《The Plant journal : for cell and molecular biology》1992,2(2):233-239
A 2.4 kb fragment containing the 5'-flanking region and the 5'-noncoding sequence of the Vicia faba legumin gene LeB4 mediates high level seed-specific expression in transgenic tobacco plants. Deleted derivatives of this legumin upstream sequence were fused to the npt-II reporter gene to determine the tissue-specific activity of the chimeric constructs in stably transformed tobacco plants. The results indicate the presence of positive regulatory, enhancer-like cis elements within 566 bp of the upstream sequence. Most importantly, however, these elements are only fully functional in conjunction with the core motif CATGCATG of the legumin box around position -95, since destruction of the motif by a 6 bp deletion in an otherwise intact 2.4 kb upstream sequence drastically reduces expression in seeds. At the same time, low level expression in leaves is observed. The occurrence of similar CATGCATG consensus cis elements with alternating purine and pyrimidine base pairs in front of several other plant genes suggests a functional role of the motif in a wider range of plant promoters. 相似文献
16.
17.
Claus König und Helmut Kaiser 《Journal of Ornithology》1985,126(4):443
Summary After a decrease and extinction due to deforestation the population has been reestablished by releasing captive-bred owls. Now about 40 territories are occupied with an average density of 0,8–1,0 territories/10 km2. Highest density: 17 territories/80 km2. 相似文献
18.
Dr. Erich Kessler 《Plant Systematics and Evolution》1985,151(1-2):67-71
The upper limit of temperature for growth is a species-specific character in the genusChlorella. The limits of 14Chlorella species range from 26–30°C (C. saccharophila) to 38–42°C (C. sorokiniana), withC. fusca var.vacuolata (34°C) andC. kessleri (34–36°C) assuming an intermediate position. Thus, there is no wide gap in the temperature limits between the normal (“low-temperature”)
species ofChlorella and the “high-temperature” species,C. sorokiniana. 相似文献
19.
Helmut Sinzinger Thomas Zidek Peter Fitscha John O'Grady Otto Wagner Josef Kaliman 《Prostaglandins & other lipid mediators》1987,33(6)
Patients suffering from peripheral vascular disease have been “ultima ratio”-treated with PGI2 at a rate of 5 ng/kg/min for 6 hours a day and 5 consecutive days i.v. 20 of them underwent surgery thereafter as therapy was not sufficient. A histological examination and quantification of vascular tissue revealed that the number of activated smooth muscle cells was significantly lower in treated patients vascular segments than in untreated ones in all the different age groups. A comparable suppression was found in the intima and the media as well. It is thus concluded, that PGI2 inhibits smooth muscle cell proliferation most probably by inhibiting PDGF-release from the platelets and stimulation of smooth muscle cell cAMP. To achieve a more beneficial PGI2-effect at the vascular level, a prolonged PGI2-therapy looks rather promising. 相似文献
20.
Dr. Erich Buchner Sigrid Buchner Garrett Crawford William T. Mason Paul M. Salvaterra David B. Sattelle 《Cell and tissue research》1986,246(1):57-62
Summary Using a monoclonal antibody selective for the acetylcholine (ACh)-synthesizing enzyme choline acetyltransferase (ChAT) of Drosophila melanogaster we find ChAT-like immunoreactivity in specific synaptic regions throughout the brain of Drosophila melanogaster apart from the lobes and the peduncle of the mushroom body and most of the first visual neuropile (lamina). Several anatomically well-defined central brain structures exhibit particularly strong binding. Characteristic differential staining patterns are observed for each of the four neuromeres of the optic lobes. Cell bodies appear not to bind this antibody. The prominent features of the distribution of ChAT-like immunoreactivity are paralleled by the distribution of acetylcholine hydrolyzing enzymatic activity as revealed by histochemical staining for acetylcholine esterase (AChE). These results are discussed in comparison with published data on enzyme distribution, choline uptake and ACh receptor binding in the nervous system of Drosophila melanogaster. 相似文献