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61.
Ciliatine (2-aminoethylphosphonic acid) was detected in the human brain, heart, kidney, liver, intestine, spleen, adrenal glands, and aorta. Phosphonoalanine (2-amino-3-phosphonopropionic acid) was found in the human liver, intestine and spleen. Tissue homogenates were extracted with trichloroacetic acid and a chloroform-methanol mixture. After hydrolysis, each fraction was subfractionated by ion-exchange chromatography and examined by paper chromatography and electrophoresis using a specific ninhydrin-molybdate staining procedure to detect the phosphonic acids. The acids were found bound either to lipid or to protein; no free phosphonic acid was detected. 相似文献
62.
Solid-phase synthesis of oligoribonucleotides using 9-fluorenylmethoxycarbonyl (Fmoc) for 5''-hydroxyl protection. 总被引:7,自引:6,他引:1
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Efficient solid-phase synthesis of a series of oligoribonucleotides of up to 20 residues is described that utilises the 9-fluorenylmethoxycarbonyl group (Fmoc) for 5'-protection and 4-methoxytetrahydropyran-4-yl (Mthp) for 2'-protection of ribonucleotide monomers and a phosphoramidite coupling procedure. The Fmoc group is removed after each coupling step by treatment with 0.1M DBU in acetonitrile. Oligoribonucleotides are isolated in 2'-protected form in good yield and shown to be readily and efficiently deprotected by mild acidic treatment. 相似文献
63.
Benito C. Tan 《Brittonia》1989,41(1):41-43
A review of the nomenclatural history ofThamnobryum subserratum andThamnobryum subseriatum shows that the former, which ranges widely from the Himalayas to Southeast Asia, has been misrepresented in the literature asThamnobryum “subseriatum,” and that the latter, which appears to be a Japanese endemic, has been called a superfluous name,Thamnobryum sandei. A new combination,Thamnobryum subseriatum (Mitt. ex Sande Lac.) Tan, is proposed for the Japanese endemic and its lectotype hereby designated. In addition, morphological differences between the two taxa are discussed. 相似文献
64.
Nonexchangeable proton resonances in the 500-MHz NMR spectrum of d-CTCGAGCTCGAG have been assigned by using two-dimensional correlated spectroscopy (COSY) and nuclear Overhauser enhancement spectroscopy (NOESY). 1H-1H coupling constants (J) in the deoxyribose rings have been measured by analyzing intensity and multiplet patterns in the phase-sensitive omega 1-scaled COSY spectra. A modification of the J-resolved technique, called amplitude-modulated J-resolved spectroscopy, has been described and used to increase the accuracy of J measurements. Absorption mode omega 1-scaled NOESY spectra at mixing times in the range 50-200 ms have been analyzed to monitor spin diffusion. A 50-ms spectrum has been used to estimate several interproton distances. The coupling constant and distance data have been used to arrive at sequence-specific sugar geometries and glycosidic torsion angles. The backbone structure has been refined by model building using the FRODO program, employing the sugar geometries and glycosidic torsion angles discussed above. The molecule shows interesting sequence-dependent variations in the structure. The cleavage site of the restriction enzyme XhoI exhibits unique differences in the sugar geometry and backbone torsion angles. 相似文献
65.
The results of four field surveys for Rotifera in Tasmania are summarized. Most new species and records in a 1987 survey were from acid waters (pH < 4.0) of dune lakes on the west coast (42° S). Marked intra- and interhabitat differences in rotifer communities of lakes and ponds were demonstrated by cluster analysis and related to habitat heterogeneity. 相似文献
66.
The breeding biology of the WheatearOenanthe oenanthe in South Sweden during three contrasting years
Juan Moreno 《Journal of Ornithology》1989,130(3):321-334
Summary The breeding phenology, territory size, egg dimensions, clutch size, nestling growth and reproductive success of a dense population of WheatearsOenanthe oenanthe was studied on the island of Öland, S. Sweden during the years 1985–1987. The 1987 season was exceptionally cold and rainy, 1986 had the warmest and driest conditions, while 1985 was intermediate with respect to weather. Cold, windy and rainy weather was associated to prolonged incubation, greater intervals between first and replacement clutches, prolonged nestling growth, lower fledging condition, increased starvation and increased predation. Large clutches were laid earlier in the season and contained relatively larger eggs than small clutches. Incubation periods decreased with clutch size. Female size was positively correlated with egg size and with clutch size. The last egg laid in a clutch had a tendency to be heavier than eggs laid previously, especially in large clutches. Nestling starvation increased with brood size in 2 years.
Zusammenfassung 1985–1987 wurden Phänologie, Siedlungsdichte, Eimaße, Gelegegröße, Jungenwachstum und Bruterfolg einer Population des Steinschmätzers auf der südschwedischen Insel Öland untersucht. 1987 waren die Lufttemperaturen besonders niedrig und die Niederschläge sehr hoch. Der Sommer 1986 wies dagegen die höchsten Temperaturen und niedrigsten Niederschläge der 3 Jahre auf. Kaltes, windiges und regnerisches Wetter war mit längerer Brütezeit, längeren Intervallen zwischen Erst- und Ersatzbruten, langsamerem Jungenwachstum, schlechterer Kondition der ausfliegenden Jungen und höheren Verlusten durch Verhungern und Beutefeinde korreliert. Die Gelegegröße nahm mit dem Legedatum ab; die größten Gelege hatten im Mittel größere Eier. Die Bebrütungszeit nahm mit der Gelegegröße ab. Größere Weibchen legten größere Eier und zeigten Tendenz, größere Gelege zu produzieren. Die zuletzt gelegten Eier waren meist die schwersten, besonders in großen Gelegen. Ausfälle durch Verhungern stiegen in 2 Jahren mit der Brutgröße.相似文献
67.
68.
Quantitative autoradiographic localization of neuropeptide Y (NPY) binding sites in rat posterior pituitary lobe 总被引:1,自引:0,他引:1
1. We have localized and quantified neuropeptide Y (NPY) binding sites in the rat pituitary gland after incubation of tissue sections in the presence of 125I-Bolton-Hunter NPY followed by autoradiography, computerized microdensitometry, and comparison to 125I-standards. 2. In the rat, NPY binding sites are localized exclusively to the part of the posterior pituitary lobe closer to the pituitary stalk. No NPY binding sites could be found in the intermediate or the anterior pituitary lobes. 3. Our results suggest a role for NPY in the regulation of pituitary function and, in particular, that of the neural lobe. 相似文献
69.
Recovery of functional DNA inserts by electroendosmotic elution during gel electrophoresis
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H V Tan A Kitzis T Berthollet G Hamard C Beldjord R Benarous 《Nucleic acids research》1988,16(5):1921-1930
In contrast to all previous preparative electrophoresis apparatus which used a pump, electroendosmotic elution uses bound electrical charges at the end of the separating gel to generate a buffer flow. The electroendosmotic flow increased with increasing currents and decreasing buffer concentrations: its exact characteristics for the built apparatus were determined. The electroendosmotic device was able to separate two DNA fragments differing in size by only 5% with a recovery over 95%. As demonstrated in practical examples of recovery and uses of DNA inserts, up to 10 micrograms of DNA per band can be loaded at a time. The recovered DNA can be used directly for nick-translation, ligation... without further treatment. The performances of the method are expected to improve still further if the charge density and pores of the electroendosmotic medium can be "made-to-order" to provide a better flow profile of the eluting buffer. 相似文献
70.
Alberto Alcázar Elena Martin Juan López-Fando Dr. Matilde Salinas 《Neurochemical research》1988,13(9):829-836
A simple and short purification procedure applicable to casein kinase II has been developed, for fully characterizing the enzyme from calf cerebral cortex cytosol. The procedure consists of four chromatographic steps: DEAE-cellulose, phosphocellulose, phosvitin-Sepharose and ATP-agarose which yields 87% pure casein kinase II. The purified enzyme shows three major bands with apparent molecular masses of 42, 38, and 27 kDa by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and is self-autophosphorylated on its 27 kDa polypeptide. The enzyme shows all the characteristics described for casein kinase II from other sources: it is independent of cyclic nucleotides, calcium/phospholipids, and double-stranded poly(I).poly(C); it can utilize both ATP and GTP as phosphoryl donors and can phosphorylate both casein and phosvitin but not histone. The kinetic studies establish that theK
m for ATP is 12.5 M and 25.1 M when using phosvitin and casein respectively as phosphoryl acceptors. TheK
m for phosvitin is 0.91 mg/ml and for casein 1.43 mg/ml, while theV
max is 315 nmol/min/per mg protein and 479 nmol/min/per mg protein for phosvitin and casein respectively. The activity of the kinase is highly stimulated by KCl or NaCl, and almost completely inhibited by heparin concentrations of 1 g/ml (92%). This inhibition is reduced to only 33% in the presence of optimal KCl concentrations (150 mM). Spermine stimulates enzyme activity, whilst hemin produces a slight inhibition. 相似文献