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151.
152.
Summary The metaphase chromosomes ofChironomus th. thummi contain approximately 17% more pericentric C-band heterochromatin than the chromosomes ofChironomus th. piger with 11% heterochromatin. InCh. th. thummi, the proportion of heterochromatin appeared to be much larger in metaphase chromosomes than in polytene chromosomes. This discrepancy is interpreted as being due to the specific chromosome organization and not as the result of an underreplication of heterochromatin during polytenization. 相似文献
153.
J. D. Walton E. D. Earle H. Stähelin A. Grieder A. Hirota A. Suzuki 《Cellular and molecular life sciences : CMLS》1985,41(3):348-350
Summary Chlamydocin, a potent cytostatic agent against cultured mammalian cells, and HC-toxin, a host-specific phytotoxin, are cyclic tetrapeptides containing the same epoxide -amino acid. We show here that these compounds have reciprocal biological activity; HC-toxin is cytostatic against cultured mastocytoma cells, and chlamydocin has host-specific toxin activity against maize. Chlamydocin and another related cyclic peptide, Cyl-2, are less host-specific than HC-toxin because maize tolerant to HC-toxin is more sensitive to chlamydocin and Cyl-2. 相似文献
154.
The killing mediated by cytotoxic T lymphocytes (CTL) represents an important mechanism in the immune defence against tumors and virus infections. The lytic mechanism has been proposed to consist of a polarized secretion of granule-stored molecules, occurring on effector-target cell contact. By electron microscopy, membrane deposited, pore-like lesions are detected on the target cell membrane during cytolysis by CTL. These structures resembled strikingly pores formed during complement attack. Granules of CTL isolated by nitrogen cavitation and Percoll gradient centrifugation were shown to retain cytotoxic activity. Further purification of proteins stored in these granules led to the discovery of a membranolytic protein named perforin which was capable of polymerizing into pore-like structures. In addition to this cytolytic protein, a set of serine esterases was found as well as lysosomal enzymes and proteoglycans, whose function are not yet clearly defined. The role of perforin in the cytotoxic process is currently being explored by ablating the active gene in mice. 相似文献
155.
156.
J. Hurter E. F. Boller E. Städler B. Blattmann H. -R. Buser N. U. Bosshard L. Damm M. W. Kozlowski R. Schöni F. Raschdorf R. Dahinden E. Schlumpf H. Fritz W. J. Richter J. Schreiber 《Cellular and molecular life sciences : CMLS》1987,43(2):157-164
Summary An oviposition-deterring pheromone (ODP) of the European cherry fruit flyRhagoletis cerasi L. was isolated from faeces using cellulose and several reverse phase TLC and HPLC procedures. The biological activity was evaluated by means of behavior tests and by electrophysiological recordings from tarsal contact chemoreceptors. The compound was structurally characterized as a N[15(-glucopyranosyl)oxy-8-hydroxypalmitoyl]-taurine by spectroscopic means. The configurations of C-8 and C-15 of the fatty acid constituent remain to be established by synthetic work. 相似文献
157.
158.
S. Wilde E. Schlatter H. Koepsell B. Edemir S. Reuter H. Pavenstädt U. Neugebauer R. Schröter S. Brast G. Ciarimboli 《Cellular and molecular life sciences : CMLS》2009,66(10):1729-1740
In this work, regulation of organic cation transporter type 2 from rat (rOCT2) stably transfected in HEK293 cells was investigated
by microfluorimetry with 4-(4-(dimethylamino)styryl)-N-methylpyridinium as substrate. The transport mediated by rOCT2 was
specifically stimulated by PKA, phosphatidylinositol-3-kinase, p56lck tyrosine kinase, mitogen-extracellular-signal-regulated-kinase-1/2, calmodulin (CaM), and CaM-kinase-II. The regulatory pattern
of rOCT2 differs markedly quantitatively and qualitatively from that of other OCT isoforms. Only CaM-dependent upregulation
is conserved throughout the OCT family. For this reason, CaM regulation of rOCT2 was also investigated in isolated S3-segments
(known to express only rOCT2) of male and female rat proximal tubules. Inhibition of CaM by calmidazolium significantly decreased
rOCT2 activity (−49.0 ± 13.6%, n = 4) in male but not female (9.0 ± 13.0%, n = 4) rats. Real-time PCR and Western blot investigations
of CaM expression in rat kidneys showed that male animals have significantly higher CaM expression. This is the first study
describing post-translational gender-dependent rOCT2 regulation.
Received 26 February 2009; accepted 16 March 2009 相似文献
159.
J. Kälin 《Cellular and molecular life sciences : CMLS》1946,2(8):272-287
Ohne Zusammenfassung 相似文献
160.
Walter Dällenbach 《Cellular and molecular life sciences : CMLS》1946,2(12):490-492
Summary New proposals concerning machines for the acceleration of electrically charged particles are briefly described with two examples (heavy particles, electrons). 相似文献