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31.
Helmut Pauly 《Radiation and environmental biophysics》1963,1(3):143-153
Zusammenfassung In der vorliegenden Arbeit wird die elektrische Leitfähigkeit und die Membrankapazität von Ehrlich-Aszitestumorzellen gemessen. Die Membrankapazität beträgt 1,7±0,3 Farad/cm2. Die spezifische Leitfähigkeit des Zytoplasmas beträgt 0,013 [
–1 cm–1]±12%. Der spezielle Verlauf der Dispersion der Dielektrizitätskonstanten und der Leitfähigkeit der Zellsuspension zeigt, daß ein sehr breites Spektrum von Relaxationszeiten vorliegt, das nicht durch die Größenverteilung der Zellen allein erklärt werden kann. Die Spektralverteilung der Relaxationszeiten hat die FormH(T)=const. Die spezifische Leitfähigkeit des Protoplasmas kann in erster Näherung durch die elektrische Beweglichkeit der Elektrolytionen in einer etwa 15%igen Proteinlösung erklärt werden.Für die Mitarbeit bei den Versuchen möchte ich Frau H.Valetas meinen Dank aussprechen.Herrn Prof. Dr. Dr. h. c. Dr. h. c.Boris Rajewsky zum 70. Geburtstag gewidmet. 相似文献
32.
Summary The leaf shape of the mutantfiliformis (fil) ofHyoscyamus niger L. is strongly modified by external factors (like nutrition and light) as well as by the height of insertion. The name filiformis refers to thread-like leaves which always occur in the inflorencence; they may also be formed in the vegetative region, especially under short day conditions. Other leaves may have a small rhombic blade or a larger blade with irregular edges and deep incisions. Even pinnate leaves have been found. In contrast to the leaves of normalHyoscyamus, all mutant leaves (hypsophylls included) have a stalk-like basal portion that seems to be homologous to the basal part of the normal blade. This mutant is caused by one recessive factor which is linked neither toann nor topall.the submarginal initials of the normalHyoscyamus blade were always found dividing according to the periclinal-anticlinal type, while in the mutant the activity of the submarginal initials frequently resulted in a primarily biseriate mesophyll (so-called double-edged segmentation).This is apparently the first time that gene control of the mode of submarginal blade growth has been observed. Further differences between mutant and normalHyoscyamus concern the venation, the lengths of palisade cells and of stomata guard cells, the frequency of stomata per mm2, and the thickness of the blade.
Mit 7 Textabbildungen 相似文献
Mit 7 Textabbildungen 相似文献
33.
Electron Microscopy of Peripheral Nerves and Neuromuscular Junctions in the Wasp Leg 总被引:1,自引:8,他引:1 下载免费PDF全文
The peripheral nerve branch innervating the femoral muscles of the common yellow jacket (Vespula carolina) has been found to possess a thick lemnoblast basement membrane and a complex mesaxon. The term "tunicated nerve" is proposed to designate the type of peripheral nerve in which one or several axons are loosely mantled by meandering, cytoplasm-enclosing membranes of the lemnoblast. The peripheral axon courses longitudinally in a groove in the muscle fiber between the plasma membrane of the muscle fiber and a cap formed by lemnoblast and tracheoblast. The junction is characterized by apposition of plasma membranes of axon and muscle fiber, abundant mitochondria, and synaptic vesicles in the axon, and aggregates of "aposynaptic granules" plus mitochondria and endoplasmic reticulum on the muscle side of the synapse. Unlike the vertebrate striated muscle fiber, no complex infolding of the synapsing plasma membrane of the muscle fiber occurs. The "connecting tissue" of the insect is formed by tracheoblasts, their basement membranes, and the basement membranes of other cells. Further mechanical support is given by the ramifying tracheoles. The physiologic roles of the specialized structures are considered. 相似文献
34.
Benzothiadiazole induces disease resistance in Arabidopsis by activation of the systemic acquired resistance signal transduction pathway 总被引:18,自引:6,他引:12
Kay A. Lawton Leslie Friedrich Michelle Hunt Kris Weymann Terrance Delaney Helmut Kessmann Theodor Staub John Ryals 《The Plant journal : for cell and molecular biology》1996,10(1):71-82
Benzothiadiazole (BTH) is a novel chemical activator of disease resistance in tobacco, wheat and other important agricultural plants. In this report, it is shown that BTH works by activating SAR in Arabidopsis thaliana. BTH-treated plants were resistant to infection by turnip crinkle virus, Pseudomonas syringae pv ‘tomato’ DC3000 and Peronospora parasitica. Chemical treatment induced accumulation of mRNAs from the SAR-associated genes, PR-1, PR-2 and PR-5. BTH treatment induced both PR-1 mRNA accumulation and resistance against P. parasitica in the ethylene response mutants, etr1 and ein2, and in the methyl jasmonate-insensitive mutant, jar1, suggesting that BTH action is independent of these plant hormones. BTH treatment also induced both PR-1 mRNA accumulation and P. parasitica resistance in transgenic Arabidopsis plants expressing the nahG gene, suggesting that BTH action does not require salicylic acid accumulation. However, because BTH-treatment failed to induce either PR-1 mRNA accumulation or P. parasitica resistance in the non-inducible immunity mutant, nim1, it appears that BTH activates the SAR signal transduction pathway. 相似文献
35.
We have purified for the first time from green leaves a multifunctional protein (MFP) involved in fatty acid -oxidation. The protein, designated MFP IV, was extracted from green leaves of three-week-old cucumber (Cucumis sativus L.) plants. Chromatography on cation exchanger, separation on hydroxylapatite, and fast-protein liquid chromatography on Phenylsuperose led to a more than 7000-fold purification and to the isolation of an apparently homogeneous 80-kDa monomeric protein. This protein is immunologically related to the glyoxysomal MFP II, as evidenced by immunodecoration with antiserum raised against MFP II. Comparison of molecular masses of all MFPs presently known revealed that the MFP prepared from green leaves (MFP IV) is distinct from MFP II (76.5 kDa) and MFP I (74 kDa) from dark-grown cotyledons. By including other properties in this comparison, we demonstrated that MFP IV can also be distinguished from the glyoxysomal MFP III (81 kDa) and the bacterially expressed MFP-a (80 kDa). Moreover, MFP IV is a constituent of leaf peroxisomes and contains the activities of 2-enoyl-CoA hydratase (EC 4.2.1.17),l-3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) and 3-hydroxyacyl-CoA epimerase.Abbreviation MFP
multifunctional protein
This work was supported by grants from the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie. 相似文献
36.
Prof. Dr. Wolf-Christian Dullo Dr. Marcos Gektidis Prof. Dr. Stjepko Golubic Dr. Georg A. Heiss Dipl. Biol. Heike Kampmann Dr. William Kiene Dipl. Ökol. Dieter K. Kroll Dipl. Biol. Martin L. Kuhrau Dr. Gudrun Radtke Dr. John G. Reijmer Dr. Götz B. Reinicke Prof. Dr. Dietrich Schlichter Prof. Dr. Helmut Schuhmacher Klaus Vogel 《Facies》1995,32(1):145-188
37.
Small intensely fluorescent (SIF) cells are paraganglionic cells derived from sympathicoblasts which may serve as interneurons,
endo-/paracrine cells or arterial chemoreceptors within sympathetic ganglia. Like paraganglionic cells of other locations,
e.g., carotid body glomus cells, they are responsive to hypoxia. Recent studies on glomus cells and other hypoxia-sensing
cells suggested the involvement of a b
558
-type cytochrome and intracellular generation of H2O2 in the process of oxygen sensing. In the present study, we demonstrate the occurrence of the small subunit of cytochrome b
558
, p22phox, in SIF cells of guinea-pig sympathetic ganglia by immunohistochemistry using two different antisera. H2O2 production was monitored in explanted intact superior cervical ganglia of 2-day-old rats by confocal laser scanning analysis
of rhodamine 123 fluorescence generated due to oxidation of dihydrorhodamine 123 by H2O2. Using this technique, SIF cell clusters appeared as sites of highest H2O2 production within the ganglia. Thus, SIF cells exhibit two key features of an oxidase system generating reactive oxygen species.
This may be involved in the proposed chain of events in oxygen sensing, but alternative cellular functions of this system
have also to be considered.
Accepted: 19 September 1996 相似文献
38.
Antoni Rozalski Lore Brade Paul Kosma Richard Moxon Shoichi Kusumoto & Helmut Brade 《Molecular microbiology》1997,23(3):569-577
Monoclonal antibodies against the lipopolysaccharide (LPS) of the deep rough mutant I-69 Rd− /b+ of Haemophilus influenzae were obtained after immunization of mice with sheep erythrocytes which had been coated with de- O -acylated LPS. Characterization of antibodies was performed by enzyme immuno assay (EIA) using LPS or neoglycoconjugates containing partial structures of LPS as solid-phase antigens and by haemagglutination with sheep erythrocytes coated with de- O -acylated LPS. Binding data were confirmed by EIA inhibition experiments using deacylated LPS or synthetic partial structures thereof. Three antibodies were specific for 3-deoxy- d - manno -octulopyranosonic acid- (Kdo) 5-phosphate, one for Kdo-4-phosphate, and one required, in addition to a Kdo-phosphate, parts of the phosphorylated glucosamine backbone of lipid A. All antibodies also bound in (i) Western blots to bacterial whole-cell lysates or isolated LPS separated by SDS–PAGE, (ii) bacterial colony blots, and (iii) immunofluorescence with live bacteria. The latter result indicated that Kdo-4- and Kdo-5-phosphate are synthesized by the bacteria and are not the result of phosphate migration. 相似文献
39.
Larvae of the two southern hemisphere lamprey genera, Mordacia and Geotria, possess one and two intestinal diverticula, respectively, each originating at the oesophageal-intestinal junction. These diverticula comprise an inner layer of simple columnar epithelium composed solely of zymogen and mucous cells, a middle layer consisting mainly of a blood sinus, and an outer serosa layer covered by a simple squamous epithelium (mesothelium). The inner surface is highly folded only in Mordacia. The secretion of mucus probably protects the epithelium from the effects of digestive enzymes secreted by the zymogen cells and/or bile, which enters the diverticulum at its tip. Unlike the situation in southern hemisphere lampreys, the zymogen cells of the larvae of holarctic lampreys are located in the anterior intestine, a condition considered to be primitive. It is thus proposed that intestinal diverticula were developed during the evolution of southern hemisphere lampreys. The relocation of zymogen cells in the diverticula increases the area for these cells, and thus the capacity for the synthesis and secretion of digestive enzymes, particularly in Mordacia where the inner surface is folded. 相似文献
40.
Attempts to induce enantioselectivity in the catalytic hydrogenation of unsymmetrically substituted aromatics using covalently bound, well known chiral auxiliaries are described. Marked differences in stereoselectivity and rate of hydrogenolysis are noted as a function of the auxiliary used. Enantioselectivities obtained in the resulting cyclohexyl derivatives are rather poor. © 1995 Wiley-Liss, Inc. 相似文献