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71.
The mesencephalic reticular formation (MRF) neurons are regarded as contributing to the activation of the celebral cortex. In this paper, the statistical features of single neuronal activities in MRF of cat during dream sleep are investigated; the neuronal spike train exhibits 1/f fluctuations. Counting statistics is applied to the neuronal spike train giving rise to a variance/mean curve which follows at
-law. For an interpretation of these findings, the clustering Poisson process is applied which not only gives rise to at
-law but also suggests a generation mechanism. The MRF neuronal activities are closely fitted by the clustering Poisson process and the underlying statistical parameters can be estimated. These findings strongly suggest that neuronal activities can be interpreted as superposition of randomly occuring clusters ( = bursts of spikes). 相似文献
72.
Günter Kämper Hans-Ulrich Kleindienst 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(2):193-200
1. | Filiform hairs of various lengths on the cerci of adult crickets vibrate in a sound field. These movements were measured with a photodetector for sound frequencies from 10 Hz to 200 Hz in the species Acheta domestica, Gryllus bimaculatus and Phaeophilacris spectrum. |
2. | With low air-particle velocities, the hair shafts were deflected sinusoidally from their resting position, without bending or secondary oscillations (Figs. 2 A, 3 A). At higher velocities (from ca. 80 mm/s peak velocity, depending on the properties of the individual hairs), the shaft struck the cuticular rim of the socket in which the base of the hair is seated (Fig. 2B). This contact was made at an average angular displacement from the resting position of 5.16°±1.0°. |
3. | The best frequencies of the hairs were found to be between 40 Hz and 100 Hz (Fig. 5A). The slope of the amplitude curve for constant peak air-particle velocity at frequencies below the best frequencies was between 0 and 6 dB/octave. Long hairs had smaller slope values than short hairs (Fig. 5C). |
4. | At its best frequency the ratio of maximal tip displacement of a hair to the displacement of the air particles in the sound field was between 0.2 and 2. Only a small number of hairs (2 out of 36) showed tip displacements exceeding twice the air-particle displacement. The values of maximal angular displacement were not correlated to hair length (Fig. 5 B). |
5. | The angular displacement of the hairs was phase shifted with respect to the air-particle velocity by 0° to +45° (phase lead) at sound frequencies around 10 Hz and by -45° to -120° (phase lag) at 200 Hz (Figs. 3C, 4B). At a particular frequency long hairs tended to have larger phase lags than shorter hairs (Fig. 5D). |
73.
Summary We raised monoclonal antibodies against a membrane fraction ofXenopus neurulae in order to detect tissue-specific cell-surface markers. Here we describe a monoclonal antibody that recognizes an epithelial membrane-associated antigen (EMA) in immunohistological stainings. The tissue-specific and membrane-associated antigen detected in immunohistological stainings could serve as useful marker in epithelium differentiation and membrane organization of the early embryo. In tadpoles and adults EMA was found in specific epithelial tissues derived from different germ layers such as kidney, skin, gut, pancreas, epiphysis and choroid plexus. In the cleaving embryo this antibody stained newly formed membranes between blastomeres from the two-cell stage onwards. Cytoplasmic staining in large oocytes and early embryos was also observed. The possibility that the cytoplasmic signal represents a maternal store of membrane material is discussed. 相似文献
74.
ADP-ribosylation of histones and non-histone nuclear proteins was studied in isolated nuclei during the naturally synchronous cell cycle of Physarum polycephalum. Aside from ADP-ribosyltransferase (ADPRT) itself, histones and high mobility group-like proteins are the main acceptors for ADP-ribose. The majority of these ADP-ribose residues is NH2OH-labile. ADP-ribosylation of the nuclear proteins is periodic during the cell cycle with maximum incorporation in early to mid G2-phase. In activity gels two enzyme forms with Mr of 115,000 and 75,000 can be identified. Both enzyme forms are present at a constant ratio of 3:1 during the cell cycle. The higher molecular mass form cannot be converted in vitro to the low molecular mass form, excluding an artificial degradation during isolation of nuclei. The ADPRT forms were purified and separated by h.p.l.c. The low molecular mass form is inhibited by different ADPRT inhibitors to a stronger extent and is the main acceptor for auto-ADP-ribosylation. The high molecular mass form is only moderately auto-ADP-ribosylated. 相似文献
75.
A heparin-binding protein involved in inhibition of smooth-muscle cell proliferation. 总被引:19,自引:0,他引:19
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W Lankes A Griesmacher J Grünwald R Schwartz-Albiez R Keller 《The Biochemical journal》1988,251(3):831-842
A heparin-binding protein was isolated from bovine uteri and purified to homogeneity. This protein appears as a double band of approx. 78 kDa in SDS/polyacrylamide-gel electrophoresis and has an isoelectric point of 5.2. The binding of heparin to this protein is saturable. No other glycosaminoglycan from mammalian tissue, such as hyaluronic acid, chondroitin sulphate, dermatan sulphate or keratan sulphate, binds to the 78 kDa protein. Dextran sulphate binds in a non-saturable fashion. Certain heparan sulphate polysaccharide structures are required for binding to the 78 kDa protein. Some proteoheparan sulphates, such as endothelial cell-surface proteoheparan sulphate, show only weak interaction with the 78 kDa protein in contrast with a basement-membrane proteoheparan sulphate from HR-9 cells. Antibodies against the 78 kDa protein inhibit binding of proteoheparan [35S]sulphate from basement membranes to smooth-muscle cells. Conventional antibodies, Fab fragments and some monoclonal antibodies, inhibit smooth-muscle cell proliferation in a similar range as that observed for heparin. The protein was detected in a variety of tissues and cells but not in blood cells. A possible role of this protein as a receptor for heparin or heparan sulphate and its function in the control of the arterial wall structure are discussed. 相似文献
76.
Circulating antibodies against Faenia rectivirgula, Thermoactinomyces candidus, T. vulgaris and Aspergillus fumigatus were studied in the sera of 14 clinically proven farmer's lung patients and 10 normal controls using three immunological methods. These methods were agar gel double diffusion (DD), biotin-avidin-linked immunosorbent assay (BALISA) and dot-immunobinding assay (DIBA). Agar gel diffusion, the least sensitive of the three methods, failed to detect antibodies in some of the patients, while BALISA detected antibodies even in the normal controls. However, the sensitivity of dot-immunobinding assay was in between DD and BALISA while the specificity was comparable to DD to all the antibodies except against A. fumigatus antigens. Dot-immunobinding assay gave faster results than DD and the blots can be stored as record for longer periods of time without fading. 相似文献
77.
Urs Kägi James G. Chafouleas Anthony W. Norman Dr. Claus W. Heizmann 《Cell and tissue research》1988,252(2):359-365
Summary Calcium and intracellular Ca2+-binding proteins are possibly involved in hormone production and spermatogenesis in rat testis. Parvalbumin, calbindin D-28K, S-100 proteins and calmodulin were localized in the Leydig cells, which are sites of testosterone synthesis. Only the appearance of parvalbumin-immunoreactivity is closely correlated to testosterone production during development of the testes. Calbindin D-28K-immunoreactivity persisted in foetal-type Leydig cells and in adult-type Leydig cells at all stages of development. S-100-immunoreactivity was low during all foetal stages, absent between birth and puberty, and increased thereafter. Calmodulin staining is most prominent in the cytoplasm of developing spermatocytes and of maturing spermatids. All four proteins co-exist in the seminiferous tubules. The distinct localization and developmental appearance of these proteins suggests different regulatory roles in Leydig cell function and spermatogenesis. 相似文献
78.
Summary The immunocytochemical localization of several substances with putative neurotransmitter or modulator properties was investigated in the retinae of three urodele species. Gamma-aminobutyric acid-like immunoreactive labelling appeared in different types of amacrine and horizontal cells. In addition, labelled fibres in the optic nerve were detected. It was not possible to determine whether these fibres were ganglion-cell axons or part of an efferent projection. Endogenous serotonin was found in several populations of amacrine cells including stratified and diffuse types. Glucagon-like immunoreactivity appeared in one bistratified amacrine cell type, and neurotensin-like immunoreactivity was detected in a single monostratified amacrine cell type. Metenkephalin-like-immunoreactive labelling was rare but found in several sublaminae of the inner plexiform layer. Thus each peptide-like-immunoreactive cell type makes up a distinct and unique population of cells and probably has a special functional role in retinal processing. There are striking similarities in the peptide-like immunoreactive patterns of Triturus alpestris and Necturus maculosus whereas in Ambystomatidae the peptide-like-immunoreactive systems appear to be differently organized. This supports the hypothesis that Salamandridae and Proteidae are more closely related to each other than to the Ambystomatidae.Abbreviations
GABA
gamma-aminobutyric acid
- GCL
ganglion cell layer
-
Glu
glucagon
-
HRP
horseradish peroxidase
-
INL
inner nuclear layer
-
IPL
inner plexiform layer
-
IR
immunoreactive or immunoreactivity
-
M-enk
metenkephalin
-
Neu
neurotensin
-
OFL
optic fibre layer
-
ONL
outer nuclear layer
-
OPL
outer plexiform layer
-
Ser
serotonin
This work forms part of the doctoral thesis of Gaby Gläsener, Faculty of Biology, Technical University of Darmstadt, Federal Republic of Germany. Supported by a research grant from the Deutsche Forschungsgemeinschaft (Hi 306/1-1) 相似文献
79.
Summary Ventral thoracic neurosecretory cells (VTNCs) of the blowflies, Calliphora erythrocephala and C. vomitoria, innervating thoracic neuropil and the dorsal neural sheath of the thoracico-abdominal ganglion have been shown to be immunoreactive to a variety of mammalian peptide antisera. In the neural sheath the VTNC terminals form an extensive neurohaemal network that is especially dense over the abdominal ganglia. The same areas are invaded by separate, ut overlapping serotonin-immunoreactive (5-HT-IR) projections derived from neuronal cell bodies in the suboesophageal ganglion. Immunocytochemical studies with different antisera, applied to adjacent sections at the lightmicroscopic level, combined with extensive cross-absorption tests, suggest that the perikarya of the VTNCs contain co-localized peptides related to gastrin/cholecystokinin (CCK), bovine pancreatic polypeptide (PP), Met- and Leuenkephalin and Met-enk-Arg6-Phe7 (Met-enk-RF). Electron-microscopic immunogold-labeling shows that some of the terminals in the dorsal sheath react with several of the individual peptide antisera, whilst others with similar cytology are non-immunoreactive. In the same region, separate terminals with different cytological characteristics contain 5-HT-IR. Both 5-HT-IR and peptidergic terminals are localized outside the cellular perineurium beneath the acellular permeable sheath adjacent to the haemocoel. Hence, we propose that various bioactive substances may be released from thoracic neurosecretory neurons into the circulating haemolymph to act on peripheral targets. The same neurons may also interact by synaptic or modulatory action in the CNS in different neuropil regions of the thoracic ganglion. 相似文献
80.
Linkage studies in X-linked Alport's syndrome 总被引:1,自引:0,他引:1
S. Szpiro-Tapia G. Bobrie M. Guilloud-Bataille S. Heuertz C. Julier J. Frézal J. P. Grünfeld M. C. Hors-Cayla 《Human genetics》1988,81(1):85-87
Summary Four kindreds segregating for Alport's syndrome (ASLN) compatible with a X-linked inheritance were studied for linkage with polymorphic markers of the human X chromosome. No recombinant was observed between the ASLN locus and the DXS101 and DXS94 loci, the maximum lod scores were z=3.93 and 3.50 respectively. Linkage data between the ASLN locus and the other genetic markers used in the present study are in keeping with the assignment of the mutation to the proximal Xq arm. 相似文献