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1.
The applicability of the electron spectroscopic imaging technique for detection of the intracellular distribution of calcium in plant cells was tested with calyptra cells ofZea mays and with pollen tubes ofLilium longiflorum. After fixation in enhanced Ca2+ levels and embedding in resin, ultrathin sections were analyzed for the elemental distribution. Calcium and phosphorus were enriched in cell wall, plasma membrane, endoplasmic reticulum, mitochondria, and Golgi vesicles, mainly in granular or globular deposits appearing electron dense in transmission electron microscopy. The results demonstrated that the ESI-technique allows exact localization of calcium enrichment relative to specific cell organelles. 相似文献
2.
Rudolf Geyer Silvia Diabaté Hildegard Geyer Hans-Dieter Klenk Heiner Niemann Stephan Stirm 《Glycoconjugate journal》1987,4(1):17-32
Fowl plague virus, strain Dutch, was metabolically labeled withd-[2-3H]mannose, or withd-[6-3H]glucosamine, and the small subunit (HA2; 0.8 mg in total) of the viral hemagglutinin was isolated by preparative sodium dodecylsulfate-polyacrylamide gel electrophoresis. After proteolytic digestion, the radioactive oligosaccharides were sequentially liberated from the glycopeptides by treatment with different endo--N-acetylglucosaminidases and with peptide:N-glycosidase or, finally, by hydrazinolysis. In this manner, four groups of glycans could be obtained by consecutive gel filtrations and were subfractionated by HPLC. The structures of the individual oligosaccharides were analyzed by micromethylation, by acetolysis or by digestion with exoglycosidases. The major species amongst the high mannose glycans at Ans-406 of the viral glycopolypeptide were found to be Man1-2Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNac1-4GlcNAc and Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNAc1-4GlcNAc, while the complex glycans at Asn-478 are predominantly GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc (lacking, in part, one of the outerN-acetylglucosamine residues) and GlcNAc1-2Man1-3(Gal1-4GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc.Abbreviation BSA
bovine serum albumin
- endo D (F,H)
endo--N-acetyl-d-glucosaminidase D (F,H)
- HA
hemagglutinin (HA1, large subunit of HA
- HA2
small subunit
- FPV
fowl plague virus
- PNGase F
peptide:N-glycosidase F
- SDS
sodium dodecylsulfate 相似文献
3.
Ciliary Neuronotrophic Factor Stimulates Choline Acetyltransferase Activity in Cultured Chicken Retina Neurons 总被引:4,自引:1,他引:3
Hans-Dieter Hofmann 《Journal of neurochemistry》1988,51(1):109-113
It has been demonstrated that cultured cholinergic retinal neurons from 8-day-old chicken embryos respond to a polypeptide factor present in retinal cell-conditioned medium (RCM) and in retinal extracts. Compared with control cultures, the activity of acetyl-CoA:choline O-acetyltransferase (EC 2.3.1.6; ChAT) is enhanced more than twofold in neuronal retinal cultures grown for 7 days in the presence of RCM. The present study demonstrates that both ciliary neuronotrophic factor (CNTF), which is characterized by its trophic activity on parasympathetic ciliary neurons, and RCM exhibit identical stimulatory effects on ChAT activity in retinal monolayer cultures. Similarly, RCM supports the in vitro survival of ciliary neurons to the same extent as CNTF. The active species in RCM has a molecular weight (20,900 +/- 1,000) identical to that of CNTF, as determined by preparative sodium dodecyl sulfate gel electrophoresis. The results indicate that cholinergic retinal neurons represent a central neuronal target for CNTF or a closely related protein. 相似文献
4.
Robert A. White Connie S. Birkenmeier Luanne L. Peters Jane E. Barker Samuel E. Lux 《Mammalian genome》1992,3(5):281-285
Ankyrin is an essential link between cytoskeletal proteins, such as spectrin, and membrane bound proteins, such as protein 3, the erythrocyte anion exchanger. Although the amino acid structure of human ankyrin is known, the functional regions have been only partially defined. Sequence comparisons between mouse and human ankyrin offer one mechanism of identifying highly conserved regions that probably have functional significance. We report the isolation and sequencing of a series of overlapping murine erythroid ankyrin (Ank-1) cDNAs from spleen and reticulocyte libraries (total span 6238 bp) and identify potentially important regions of murine-human reticulocyte ankyrin homology. Comparison of the predicted peptide sequences of mouse and human erythroid ankyrins shows that these ankyrins are highly conserved in both the N-terminal, protein 3 binding domain (96% amino acid identity) and in the central spectrin-binding domain (97% identity), but differ in the C-terminal regulatory domain (79% identity). However, the C-terminal regulatory domain contains two regions of peptide sequence that are perfectly conserved. We postulate these regions are important in the regulatory functions of this domain. 相似文献
5.
Progenitor cells from embryonic chick dorsal root ganglia differentiate in vitro to neurons: biochemical and electrophysiological evidence. 总被引:4,自引:0,他引:4 下载免费PDF全文
We have analyzed the appearance of neurons and glial cells in chick dorsal root ganglia during development. Neurons were identified by the presence of polysialogangliosides recognized by tetanus toxin (GD1b, GT1) or by the monoclonal antibody Q211 directed against polysialogangliosides containing four, five and six sialic acid residues. Glial cells were identified by the presence of 04 antigen. A population of undifferentiated cells, i.e., cells which express neither neuronal nor glial cell surface antigens, present in dorsal root ganglia until embryonic day 7, was separated from the neuronal and glial population. This cell population contains neuronal progenitor cells which differentiate to neurons within 1 day in culture. This differentiation process is characterized by the appearance of neuronal morphology, of neuron-specific gangliosides and by the appearance of voltage-dependent sodium and calcium channels. 相似文献
6.
7.
Gabriele Schulz Klaus Peter Ulbrich Carl Hauenschild Hans-Dieter Pfannenstiel 《Development genes and evolution》1989,198(1):29-33
Summary In most nereids sexual maturation is accompanied by a dramatic reorganization of the body that enables swarming of the formerly benthic worms. However, a border exists between unchanged anterior (atokous) and metamorphosed posterior (epitokous) segments. The site of this atokous-epitokous border (a/e border) is different in sexually mature males and females of Platynereis dumerilii. There is no correlation between the total number of setigerous segments of a specimen and the location of the a/e border. The location of the a/e border and sexual development are affected neither by cutting off caudal segments of juveniles (including the prospective a/e border) nor by transecting the ventral nerve cord. When parapodia are transplanted from prospective epitokous regions to prospective atokous regions and vice versa, they maintain their original character during metamorphosis. The results presented here suggest that prospective atokous as well as epitokous characters are determined at or only very shortly after formation of the respective segments. Thus the a/e border is established well in advance of the onset of epitokous metamorphosis. 相似文献
8.
A microdeletion of less than 250 kb, including the proximal part of the FMR-1 gene and the fragile-X site, in a male with the clinical phenotype of fragile-X syndrome 下载免费PDF全文
Doris Whrle Dieter Kotzot Mark C. Hirst Antonella Manca Bernhard Korn Angela Schmidt Gotthold Barbi Hans-Dieter Rott Annemarie Poustka Kay E. Davies Peter Steinbach 《American journal of human genetics》1992,51(2):299-306
A gene designated "FMR-1" has been isolated at the fragile-X locus. One exon of this gene is carried on a 5.1-kb EcoRI fragment that exhibits length variation in fragile-X patients because of amplification of or insertion into a CGG-repeat sequence. This repeat probably represents the fragile site. The EcoRI fragment also includes an HTF island that is hypermethylated in fragile-X patients showing absence of FMR-1 mRNA. In this paper, we present further evidence that the FMR-1 gene is involved in the clinical manifestation of the fragile-X syndrome and also in the expression of the cellular phenotype. A deletion including the HTF island and exons of the FMR-1 gene was detected in a fragile X-negative mentally retarded male who presented the clinical phenotype of the fragile-X syndrome. The deletion involves less than 250 kb of genomic DNA, including DXS548 and at least five exons of the FMR-1 gene. These data support the hypothesis that loss of function of the FMR-1 gene leads to the clinical phenotype of the fragile-X syndrome. In the fragile-X syndrome, there are pathogenetic mechanisms other than amplification of the CGG repeat that do have the same phenotypic consequences. 相似文献
9.
The details of spermatogenesis and spermiogenesis are described forOphryotrocha puerilis. The ultrastructure of mature sperm is shown forO. puerilis, O. hartmanni, O. gracilis, O. diadema, O. labronica, andO. notoglandulata. Clusters of sixteen cells each are proliferated by two stem cells in each setigerous segment ofO. puerilis representing the very early stages of both oogenesis and spermatogenesis. In each spermatocyte-I cluster, the cells are interconnected
by cytoplasmic bridges. Early, clusters are enveloped by peritoneal sheath cells. These transient gonad walls break down prior
to meiosis. The meiotic processes may start in the clusters with the cells still interconnected, or during breakdown of the
original cluster, giving rise to smaller subclusters of both spermatocytes I and spermatocytes II with various numbers of
cells. Finally, spermatid tetrads are present. As spermiogenesis progresses, the tetrads disintegrate. Golgi vesicles in both
spermatocytes and spermatids contain electron-dense material, presumably preacrosomal. The acrosome is formed by such vesicles.
In the six species studied here, the acrosomes appear to be of a similar overall structure but are of different shape. Centrioles
are usually located beneath the acrosome. The distal centriole forms the basal body of a flagellum-like cytoplasmic process.
The microtubules of these flagellar equivalents do not show a normal ciliar arrangement. The flagellar equivalent appears
to be non-motile. InO. hartmanni and inO. notoglandulata, a flagellar equivalent is missing. Microtubules originating from the proximal end of the distal centriole stretch to the
nuclear envelope. This feature appears to be especially conspicuous inO. puerilis and inO. labronica. InO. labronica and inO. notoglandulata, bundles of microtubules paralleling the cell perimeter appear to stabilise the sperm. Various numbers of mitochondria are
either randomly distributed around the nucleus or accumulate on one side, often directly under the acrosome.
Parts of the present paper were presented at the 2nd International Polychaete Conference, Copenhagen 1986 and at the 3rd International Polychaete Conference, Long Beach, Ca. 1989. 相似文献
10.
Zusammenfassung An Blutausstrichen und Gewebsschnitten von männlichen und weiblichen Mäusen und Ratten wurde das Vorkommen von geschlechtsspezifischen morphologischen Kernmerkmalen untersucht. Die Kerne der neutrophilen Granulocyten weisen bei beiden Arten keine an den Kernanhängen erkennbare Geschlechtsdifferenz auf. An den Kernen der Parenchymzellen wurde für weibliche und auch für männliche Tiere ein positiver Geschlechtsnachweis auf Grund einer charakteristischen Chromatinverteilung geführt.Wir stimmen dem Vorschlag von Th. Lüers (1957) zu, die Begriffe Geschlechts-bestimmung und Geschlechtsdifferenzierung nur in ihrer ursprünglichen Bedeutung zu verwenden. 相似文献