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31.
32.
Irreversible binding to the receptor of bacteriophages T5 and BF23 does not occur with the tip of the tail. 总被引:6,自引:3,他引:3 下载免费PDF全文
Treatment of purified tails of bacteriophage T5 with 0.05% sodium dodecyl sulfate specifically removed pb2, a protein of 108,000 molecular weight (108K), from the tail. Although these tails were devoid of the single straight tail fiber, they still inhibited adsorption of T5 to Escherichia coli cells. Reconstitution of these tails with pb2 increased the efficiency of inhibition of T5 adsorption. Treatment of tails with 0.1% sodium dodecyl sulfate removed, in addition to pb2, a protein of 67K from phage T5 and one of 60K from phage BF23. These tails failed to inhibit phage adsorption, and no reconstitution was achieved. Reconstitution of T5 tails with pb2 from BF23, and of BF23 tails with pb2 from T5, did not alter the host receptor specificity of the tails. Binding of untreated T5 tails to small FhuA receptor particles revealed that binding occurred with the conical part of the tail and that pb2 was most likely released from the tail upon binding. From these results and from recent observations with T5-BF23 hybrid phages (K.J. Heller, Virology 139:11-21, 1984), we conclude that the receptor-binding proteins of T5 and BF23 are the 67K and 60K proteins, respectively, and that they are not located at the tip of the tail but rather at or near the site where the straight tail fiber is attached to the conical part of the tail. 相似文献
33.
Christina Scharnhorst Hartmut Heinze Gabriele Meyer Waldemar Kolanus Klaus Bartsch Susanne Heinrichs Thomas Gudschun Margret Möller Frank Herzfeld 《Plant molecular biology》1985,4(4):241-245
Summary cDNA clones were isolated for a chloroplast protein, the mRNA of which is induced to maximum levels within 2–4 h after onset
of illumination in five day old, etiolated pea seedlings.
The cDNA library was constructed from poly(A)+-mRNA which was isolated from 4 h illuminated seedlings. The extremely short induction period of the early light induced protein(ELIP)-mRNA
established the basis of our screening procedure. Colony hybridization experiments were performed with32P-labelled cDNA probes, synthesized from RNA of seedlings which had been exposed to different programs of illumination. Plasmid
DNAs were isolated from colonies showing strong hybridization signals exclusively with cDNA corresponding to the 4 h-mRNA.
Hybrid released translation of preselected plasmids p 17/C2 and p17/C4 revealed a peptide of Mr 24 000. After posttranslational importin vitro, the processed product of Mr 17 000 appears in the chloroplast. Using these clones, the expression of the ELIP-mRNA was investigated by DOT-hybridization.
The ELIP-mRNA reaches maximum levels within 2–4 hours after onset of illumination. Our results correspond precisely to thein vivo characteristics and indicate positive identification of the sought clones. 相似文献
34.
All out anaerobic capacity tests on cycle ergometers. A comparative study on men and women 总被引:2,自引:0,他引:2
H Vandewalle G Pérès J Heller H Monod 《European journal of applied physiology and occupational physiology》1985,54(2):222-229
We have studied the effects of the braking force on the results of an anaerobic capacity test derived from the Wingate test (an all out 45 s exercise on a Monark 864 cycle ergometer against a given force at the fastest velocity from the beginning to the end of the test). Seven men and seven women participated in the study and performed a total of 63 all-out tests against different braking forces. The same subjects performed a force-velocity test on the same cycle ergometer. Since the relationship between force and velocity is approximately linear for peak velocities between 100 and 200 rev X min-1 (Pérès et al. 1981a, b; Nadeau et al. 1983; Vandewalle et al. 1983) we characterized each subject by three parameters: P0 (the intercept of the force-velocity regression line with the force axis), V0 (the intercept of the regression line with the velocity axis) and Wmax (maximal power). The relationship between force and mean power was parabolic for the all-out anaerobic capacity test. In the present study the optimal force (the force giving the maximal value of mean power during an all out test) was higher for the men (approximately 1 N X kg BW-1) than the force proposed by others (0.853 N X kg BW-1 for Dotan and Bar-Or 1983). However, because of the parabolic relationship between force and mean power, the mean power which corresponds to the optimal force was approximately the same in both studies.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
35.
Structural correlates of cellular tumorigenicity and anchorage independence in transformed fibroblasts 总被引:1,自引:0,他引:1
The ability on nonhematopoietic cells to proliferate in vitro without attachment to a solid surface (anchorage independence) is known to be highly correlated with their ability to form tumors in nude mice. Transformed cells in vitro frequently also show less organization of the intracellular actin-containing microfilament bundles and less cell-surface fibronectin compared to normal cells. We have examined whether the loss of the anchorage requirement for growth is related to either of these structural changes in the cellular cytoskeleton. Our approach was to select a series of subclones from a nontransformed Syrian hamster fibroblast line, NIL8, for the acquisition of either anchorage independence in vitro or tumorigenicity in nude mice. These subclones were then examined for concomitant changes in the cytoskeletal structures. We found that anchorage independence, decreased actin cable organization, and tumorigenicity in nude mice were coordinately induced in both the in vitro- and in vivo-selected subclones, whereas the loss of fibronectin was not consistently coinduced with these three markers. These results suggest that the transformation-associated decrease in actin cable organization in this type of cell enhances the ability to grow without anchorage in vitro and to form tumors in vivo. 相似文献
36.
Solubilization and partial purification of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase 总被引:5,自引:0,他引:5
This paper describes an effective method for the solubilization of microsomal HMG-CoA reductase from rat liver. Exposing the microsomes to a freeze-thaw treatment solubilized 80% of the microsomal reductase activity. Subsequently, a 25-fold purification has led to an enzyme preparation with a specific activity of 10–14 nmoles MVA per min per mg of protein and an increased stability. 相似文献
37.
38.
Hartmut Walter 《Journal of Ornithology》1965,106(1):81-105
Zusammenfassung Das Vogelleben der Mittelmeerländer ist in der Zeit der Winterregen bisher kaum untersucht worden. Verf. teilt deshalb Beobachtungsergebnisse von der Insel Sardinien mit, die er vom 15. X. 1961–15. III. 1962 während eines Studienaufenthaltes machen konnte. Der genannte Zeitraum umfaßt Beginn und Ende der sardischen Regenzeit und wird als Winter bezeichnet.Insgesamt wurden 125 Vogelarten beobachtet, von denen 65 Jahresvögel, 56 Gastvögel und 4 Sommervögel Sardiniens sind.Bei den Jahresvögeln interessierte vor allem die Vertikalverbreitung. Im Vergleich mit der Vertikalverbreitung zur Brutzeit ergeben sich teilweise beträchtliche Verschiebungen der Höhengrenzen. Für 10 Jahresvögel wird auch die horizontale Verbreitung mit Punktkarten dargestellt. Weitere Kapitel behandeln Biotope, Schwarmbildung und Vergesellschaftung sowie den Gesang im Winter.Die Gastvögel werden nach ihrer Herkunft untersucht, wobei über 260 Ringfunde ausgewertet werden. Auch über Ankunft und Abzug, Massenschlafplätze und Wasservogelleben der Gastvögel wird berichtet.In einer tabellarischen Übersicht sind wichtige Daten aller beobachteten Jahres- und Gastvögel zusammengefaßt.Abschließend werden Aufgaben der weiteren ornithologischen Erforschung Sardiniens genannt, die vor allem in der Erkundung abgelegener Gebirgsteile und weiterer Beobachtertätigkeit in den Winter- und Sommermonaten bestehen.
Für seine ständige, wertvolle Hilfe und Beratung bei meiner ornithologischen Tätigkeit auf Sardinien danke ich Herrn Prof. Dr.G. Niethammer, für die Ermöglichung meines Studienaufenthalts Herrn Prof. Dr. Dr.R. Lehmensick sehr herzlich. Dank abstatten möchte ich auch den Universitäten Bonn und Cagliari sowie vielen sardischen Freunden, die mir auf vielfältige Weise behilflich waren. HerrnH. E. Wolters danke ich für die Durchsicht des Manuskripts. 相似文献
Summary The bird life of the Mediterranean countries has hardly been studied during the period of the winter rains. Therefore the author records of observations results made on Sardinia from the 15th of October, 1961 to the 15th of March, 1962 while studying. The period mentioned above comprises the beginning and end of the Sardinian rain period, which is termed winter.Alltogether 125 bird species have been observed, 65 of which were resident, 56 visitors and 4 Sardinian summer birds.Above all the elevation distribution of residents was of interest. Comparing the vertical distribution during the breeding period with that during the winter period considerable displacements in the elevation limits were shown. For 10 residents the horizontal distribution is also described by means of dotted maps. Further chapters deal with the environment, flock formation, socialization and the winter song.The breeding regions of the visitors has been studied from the records of more than 260 ringed birds. Reports of the visitors' arrival and departure, mass sleeping places and aquatic life was also given.In a tabulated survey important facts are summarized of all residents and visitors.Finally, problems of further ornithological studies on Sardinia are mentioned which are exploration of remote mountain parts and further observation during the winter and summer periods.
Riassunto La vita degli uccelli del bacino mediterraneo è stata fino ad oggi poco esaminata durante la stagione delle piogge.Perciò l'autore comunica i risultati delle sue osservazioni, fatte nell'isola di Sardegna durante un soggiorno di studio dal 15. X. 1961 al 15. III. 1962.Questo periodo comprende l'inizio e la fine della stagione sarda delle piogge ed è chiamato inverno.In tutto furono osservate 125 specie, delle quali 65 sono stazionarie, 56 ospiti e 4 uccelli d'estate di Sardegna.La distribuzione verticale degli uccelli stazionari risulta di particolare interesse.Si riscontrano considerevoli spostamenti dei limiti d'altezza, confrontando la distribuzione verticale d'inverno e d'estate.Cartelli di punti mostrano la distribuzione orizzontale per 10 uccelli stazionari.Altri capitoli trattano di biotopi, formazioni di stormi, socializzazioni e canto d'inverno.La provenienza degli ospiti è studiata secondo la valorizzazione di più di 260 ritrovamenti di uccelli inanellati.Vengono trattati anche l'arrivo e la partenza degli ospiti, i posti per dormire in massa e la vita degli uccelli acquatici.Dati importanti su tutti gli uccelli, sia stazionari che ospiti, sono raccolti in un quadro sinottico.Infine si fa cenno ad altri problemi degli studi ornitologici in Sardegna, che consistono soprattutto nella esplorazione delle montagne remote ed in ulteriori osservazioni, sia nella stagione invernale che in quella estiva.
Für seine ständige, wertvolle Hilfe und Beratung bei meiner ornithologischen Tätigkeit auf Sardinien danke ich Herrn Prof. Dr.G. Niethammer, für die Ermöglichung meines Studienaufenthalts Herrn Prof. Dr. Dr.R. Lehmensick sehr herzlich. Dank abstatten möchte ich auch den Universitäten Bonn und Cagliari sowie vielen sardischen Freunden, die mir auf vielfältige Weise behilflich waren. HerrnH. E. Wolters danke ich für die Durchsicht des Manuskripts. 相似文献
39.
Hartmut Müller Dalibor Povolny Einhard Bezzel Victor Wendland Klaus Ruge E. v. Toll W. O. Fellenberg Frank Hampel H. Löhrl und Hans Erkert 《Journal of Ornithology》1966,107(3-4):352-361
Zusammenfassung Ein Paar Türkentauben brütete vom 29. 1. bis 15. 2. 1966 auf einem Straßenbaum in Berlin-Tempelhof. Es wurde nur ein Ei gelegt. Nach 17 Tagen schlüpfte das gelbbedaunte Junge. Es ist dann kurz danach, wahrscheinlich beim Umherkriechen auf dem Nestrand, erfroren. Die Umstände, unter denen die Brut erfolgte, waren äußerst ungünstig. Die Temperatur lag seit dem 7. 2. 1966 dauernd unter Null (–9 und –13 Grad). Die brütende Taube hatte von Anfang an auf dem Nestrand brüten müssen, da die Mulde schon vor der Eiablage völlig mit Schnee bedeckt war. Der brütende Vogel war mehrere Tage und Nächte von einem hohen Schneewall umgeben, der sich auf dem Nest gebildet hatte. Dieses Nest wurde von Mai 1964 an viermal von einem Türkentaubenpaar zum Brüten benutzt. Es wird vermutet, daß zum mindesten der eine Partner, der Tauber, während der ganzen Zeit derselbe geblieben ist. 相似文献
40.