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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
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Summary
Gossypium hirsutum L. var. Delta Pine 61 was cultivated in controlled-environment chambers at 1000–1100 mol photosynthetically active photons m-2 s-1 (medium photon flux density) and at 1800–2000 mol photons m-2 s-1 (high photon flux density), respectively. Air temperatures ranged from 20° to 34°C during 12-h light periods, whereas during dark periods temperature was 25° C in all experiments. As the leaf temperature decreased from about 33° to 27° C, marked reductions in dry matter production, leaf chlorophyll content and photosynthetic capacity occurred in plants growing under high light conditions, to values far below those in plants growing at 27° C and medium photon flux densities. The results show that slightly suboptimum temperatures, well above the so-called chilling range (0–12° C), greatly reduce dry matter production in cotton when combined with high photon flux densities equivalent to full sunlight.Abbreviations DW
dry weight
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F
v
variable fluorescence yield
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F
M
maximum fluorescence yield
- PFD
photon flux density (400–700 nm) 相似文献
14.
Mitotic chromosomes, interphase cell nuclei, and male meiosis of 41 species representing all vertebrate classes were analyzed with distamycin A/mithramycin counterstaining. The purpose of the study was to recognize differences and common characteristics in the reverse (R) fluorescent banding patterns in the chromosomes of vertebrate species at various stages of evolution. In contrast to the warm-blooded mammals and birds, the euchromatic segments in the chromosomes of most reptiles, amphibians, and fishes contain no multiple fluorescent R-bands. This is thought to be due to the absence of the long homogeneous regions (isochores) in the DNA of the cold-blooded vertebrates. Distamycin A/mithramycin banding specifically reveals the GC-rich constitutive heterochromatin in all vertebrates. In most of the vertebrate chromosomes examined, the heterochromatic regions have opposite staining properties with mithramycin and quinacrine. Mithramycin labels the nucleolus organizer regions very brightly in the karyotypes of fishes, amphibians, reptiles and birds, but not of mammals. The lack of mithramycin fluorescence at the nucleolus organizer regions of mammals is attributed to the relatively low level of redundancy of the GC-rich ribosomal DNA in their genomes. Studies on the various meiotic stages of the cold-blooded vertebrates show that the mithramycin labeling of the nucleolus organizers is independent of their state of activity. This can be confirmed by mithramycin fluorescence at the nucleoli of actinomycintreated cells.Dedicated to the memory of Professor Dr. Hans Bauer 相似文献
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Stress and Age Related Spots with Immunoreactivity to Ubiquitin-Antibody at Protoplast Surfaces 总被引:2,自引:0,他引:2
Schulz Margot; Janssen Martina; Knop Mona; Schnabl Heide 《Plant & cell physiology》1994,35(4):551-556
Mesophyll protoplasts from primary leaves of 2, 3, and 4 weekold Viciafaba L. plants and from not expanded leaves of 2 weekold plants were incubated with rabbit anti-ubiquitin antibodyand FITC labeled goat anti-rabbit IgG. Dependent on age of theplant material, an increase in size and number of immunoreactivespots at protoplast surfaces were observed, when incubationswere performed after 16 h storage to allow protoplast to recover.A relationship between isolation stress and the intensity ofimmunolabeling was demonstrated for protoplasts from not expandedleaves. Furthermore, the surface of isolation stressed protoplastsshowed an increasing number of immunoreactive spots when plantswere previously exposed to water deficiency conditions for 1,2 or 4 days. Water deficiency conditions and isolation stressare therefore thought to induce ubiquitination of surface locatedproteins. A phenomenon, which seemed to be normally correlatedwith early events of senescence. (Received October 28, 1993; Accepted February 21, 1994) 相似文献
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Filamentous algae in eutrophic carp ponds in South Bohemia (Central Europe) were studied from 1988 to 1990. High biomass (490 g DW m-2) was attained by Cladophora fracta (O. F. Müll. ex Vahl) Kütz. after two months of growth. This marked growth depleted inorganic carbon in the water, but did not decrease the concentration of tissue nutrients. Laboratory measurements of final pH indicate that all the filamentous algae studied, except for Tribonema, are very efficient HCO3
- users. An extremely high pH of 11.6 and oxygen concentration of 32 mg l-1 were measured in the algal mats. High pH resulted in CaCO3 precipitation, visible as white incrustations on algal filaments. The amount of precipitated CaCO3 reached 134 kg ha-1. After reaching peak biomass, 90% of the Cladophora decomposed over the next 95 days.The highest net photosynthetic rate in C. fracta was measured between pH range 8.5–10.0 and oxygen concentrations of 7–12 mg l-1. Optimum temperature for photosynthesis was between 17–22°C. 相似文献
20.
The main barriers to the movement of water and ions in young roots of Zea mays were located by observing the effects of wounding various cell layers of the cortex on the roots' hydraulic conductivities and root pressures. These parameters were measured with a root pressure probe. Injury to the epidermis and cortex caused no significant change in hydraulic conductivity and either no change or a slight decline in root pressure. Injury to a small area of the endodermis did not change the hydraulic conductivity but caused an immediate and substantial drop in root pressure. When large areas of epidermis and cortex were removed (15–38% of total root mass), the endodermis was always injured and root pressure fell. The hydraulic conductance of the root increased but only by a factor of 1.2–2.7. The results indicate that the endodermis is the main barrier to the radial movement of ions but not water. The major barrier to water is the membranes and apoplast of all the living tissue. These conclusions were drawn from experiments in which hydrostatic-pressure differences were used to induce water flows across young maize roots which had an immature exodermis and an endodermis with Casparian bands but no suberin lamellae or secondary walls. The different reactions of water and ions to the endodermis can be explained by the huge difference in the permeability of membranes to these substances. A hydrophobic wall barrier such as the Casparian band should have little effect on the movement of water, which permeates membranes and, perhaps, also the Casparian bands easily. However, hydrophobic wall depositions largely prevent the movement of ions. Several hours after wounding the endodermis, root pressure recovered to some extent in most of the experiments, indicating that the wound in the endodermis had been partially healed.Abbreviations Lpr
hydraulic conductivity of root; T1/2 = half-time of water exchange between root xylem and external medium
This research was supported by a grant from EUROSILVA (project no. 39473C) to E.S., and by a Bilateral Exchange Grant jointly funded by the Deutsche Forschungsgemeinschaft and the Natural Sciences and Engineering Research Council of Canada to C.A.P. We thank Mr. Burkhard Stumpf for his excellent technicial assistance. 相似文献