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991.
Summary
Dunaliella cells exhibit different temperature optima for photosynthesis and cell division. Using this observation a combined light-dark and highlow temperature treatment is given to synchronize cell suspensions. 相似文献
992.
Ferenc Rozgonyi Helmut Hahn Harald Labischinski Peter Giesbrecht 《FEMS microbiology letters》1990,71(1-2):11-15
L-[4,5-3H]isoleucine was introduced to label anteiso-fatty acid (AIFA)-containing lipids in Staphylococcus aureus SG 511. After an overnight incubation in peptone broth in the presence of 37 kBq L-[4,5-3H]isoleucine/ml, 8.5-13% of the total radioactivity applied was found to be incorporated into the cells. 22.4-25.6% of the incorporated radioactivity was found in AIFA-containing lipids extracted by chloroform-methanol-water (2:1:0.2, v/v/v) at pH 2. The interphase contained 70-75% of the incorporated radioactivity. Lipoteichoic acid, extracted by phenol-water (80:20, w/v) contained less than 1% of the incorporated radioactivity, as measured after purification by hydrophobic interaction chromatography on octyl sepharose gel. Within 1 h after addition of 10 micrograms/ml penicillin G to exponentially growing cultures of S. aureus, that led to non-lytic death of the cells, 11.9-18.1% of the incorporated L-[4,5-3H]isoleucine label were released. Lipids containing AIFA were excreted to 5.4-8.4% of total incorporated activity; this amount represents more than 1/4 of the labeled cellular lipids. 相似文献
993.
Helmut Altner Dr. Jürgen Boeckh 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1967,55(3):299-306
Zusammenfassung Aus dem Riechepithel von Rana esculenta wurden mit metallgefüllten Mikropipetten Aktionspotentiale einzelner Rezeptoren abgeleitet (Dauer 4–7 msec, maximale Frequenz 10 Imp./sec). Die Reaktionen von 25 Zellen auf 28 Duftstoffe werden beschrieben.Fast alle daraufhin geprüften Zellen reagieren auf Oenanthaldehyd, Amylacetat, Capronsäureäthylester und Caprylsäureäthylester mit einer Erhöhung der Impulsfrequenz (Grundspektrum). Außerdem haben die Rezeptoren ein variables Beispektrum geringen Umfanges.
Herrn Prof. Dr. H. Autrum zum 60. Geburtstag gewidmet. 相似文献
Odor specificities of receptors in the olfactory epithelium of the frog Rana esculenta
Summary Action potentials from single receptors in the olfactory epithelium of water frogs (Rana esculenta) have been recorded by means of metal filled glass pipettes. The reactions of 25 cells to stimulation with 28 odorous substances are described. All cells so far tested showed an increase in spike frequency when stimulated with heptanal, amyl acetate, the ethyl ester of hexanoic acid, and the ethyl ester of octanoic acid, (basic spectrum). An additional small but variable reaction spectrum (side spectrum) was recorded.
Herrn Prof. Dr. H. Autrum zum 60. Geburtstag gewidmet. 相似文献
994.
995.
996.
Dr. Helmut W. Sauer 《Zoomorphology》1966,56(2):143-251
Ohne ZusammenfassungMeinem verehrten Lehrer, Herrn Prof. Dr. F. Seidel, möchte ich für seine Unterstützung und sein stetes Interesse an dem Verlauf meiner Untersuchungen herzlich danken. Der Senatskommission für die Auswahl der Doktoranden-Stipendien der Fritz-Thyssen-Stiftung danke ich sehr für die Zusprache eines Doktoranden-Stipendiums. 相似文献
997.
Cristoforo Simonetto Helmut Sch?llnberger Tamara V. Azizova Evgenia S. Grigoryeva Maria V. Pikulina Markus Eidemüller 《PloS one》2015,10(5)
A detailed analysis of cerebrovascular diseases (CeVD) for the cohort of workers at Mayak Production Association (PA) is presented. This cohort is especially suitable for the analysis of radiation induced circulatory diseases, due to the detailed medical surveillance and information on several risk factors. The risk after external, typically protracted, gamma exposure is analysed, accounting for potential additional internal alpha exposure. Three different endpoints have been investigated: incidence and mortality from all cerebrovascular diseases and incidence of stroke. Particular emphasis was given to the form of the dose-response relationship and the time dependence of the radiation induced risk. Young attained age was observed to be an important, aggravating modifier of radiation risk for incidence of CeVD and stroke. For incidence of CeVD, our analysis supports a dose response sub-linear for low doses. Finally, the excess relative risk per dose was confirmed to be significantly higher for incidence of CeVD compared to CeVD mortality and incidence of stroke. Arguments are presented for this difference to be based on a true biological effect. 相似文献
998.
Johannes Taubert Bo Hou H. Jelger Risselada Denise Mehner Heinrich Lünsdorf Helmut Grubmüller Thomas Brüser 《PloS one》2015,10(3)
The Tat system can transport folded, signal peptide-containing proteins (Tat substrates) across energized membranes of prokaryotes and plant plastids. A twin-arginine motif in the signal peptide of Tat substrates is recognized by TatC-containing complexes, and TatA permits the membrane passage. Often, as in the model Tat systems of Escherichia coli and plant plastids, a third component – TatB – is involved that resembles TatA but has a higher affinity to TatC. It is not known why most TatA dissociates from TatBC complexes in vivo and distributes more evenly in the membrane. Here we show a TatBC-independent substrate-binding to TatA from Escherichia coli, and we provide evidence that this binding enhances Tat transport. First hints came from in vivo cross-linking data, which could be confirmed by affinity co-purification of TatA with the natural Tat substrates HiPIP and NrfC. Two positions on the surface of HiPIP could be identified that are important for the TatA interaction and transport efficiency, indicating physiological relevance of the interaction. Distributed TatA thus may serve to accompany membrane-interacting Tat substrates to the few TatBC spots in the cells. 相似文献
999.
Anja Ulmer Klaus Dietz Isabelle Hodak Bernhard Polzer Sebastian Scheitler Murat Yildiz Zbigniew Czyz Petra Lehnert Tanja Fehm Christian Hafner Stefan Schanz Martin R?cken Claus Garbe Helmut Breuninger Gerhard Fierlbeck Christoph A. Klein 《PLoS medicine》2014,11(2)
Background
Sentinel lymph node spread is a crucial factor in melanoma outcome. We aimed to define the impact of minimal cancer spread and of increasing numbers of disseminated cancer cells on melanoma-specific survival.Methods and Findings
We analyzed 1,834 sentinel nodes from 1,027 patients with ultrasound node-negative melanoma who underwent sentinel node biopsy between February 8, 2000, and June 19, 2008, by histopathology including immunohistochemistry and quantitative immunocytology. For immunocytology we recorded the number of disseminated cancer cells (DCCs) per million lymph node cells (DCC density [DCCD]) after disaggregation and immunostaining for the melanocytic marker gp100. None of the control lymph nodes from non-melanoma patients (n = 52) harbored gp100-positive cells. We analyzed gp100-positive cells from melanoma patients by comparative genomic hybridization and found, in 45 of 46 patients tested, gp100-positive cells displaying genomic alterations. At a median follow-up of 49 mo (range 3–123 mo), 138 patients (13.4%) had died from melanoma. Increased DCCD was associated with increased risk for death due to melanoma (univariable analysis; p<0.001; hazard ratio 1.81, 95% CI 1.61–2.01, for a 10-fold increase in DCCD + 1). Even patients with a positive DCCD ≤3 had an increased risk of dying from melanoma compared to patients with DCCD = 0 (p = 0.04; hazard ratio 1.63, 95% CI 1.02–2.58). Upon multivariable testing DCCD was a stronger predictor of death than histopathology. The final model included thickness, DCCD, and ulceration (all p<0.001) as the most relevant prognostic factors, was internally validated by bootstrapping, and provided superior survival prediction compared to the current American Joint Committee on Cancer staging categories.Conclusions
Cancer cell dissemination to the sentinel node is a quantitative risk factor for melanoma death. A model based on the combined quantitative effects of DCCD, tumor thickness, and ulceration predicted outcome best, particularly at longer follow-up. If these results are validated in an independent study, establishing quantitative immunocytology in histopathological laboratories may be useful clinically. Please see later in the article for the Editors'' Summary 相似文献1000.
Bernd Gröttrup Helmut Heinsen Katrin Marcus Helmut E. Meyer Young Mok Park Lea T. Grinberg 《Proteomics》2014,14(11):1305-1307
The HUPO Brain Proteome Project (HUPO BPP) held its 20th workshop in Yokohama, Japan, September 15, 2013. The focus of the autumn workshop was on new insights and prospects of neurodegenerative diseases. 相似文献