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171.
6-C-α-l-Arabinopyranosyl- and furanosylacacetins have been synthesized. They are isomerized by short acid treatment to give a mixture of the four anomer/ring size combinations without any Wessely-Moser isomerization. In the same conditions molludistin (8-C-α-l-arabinopyranosylgenkwanin) led only to a mixture of molludistin and 8-C-α-l-arabinofuranosylgenkwanin. This is the first demonstration of ring sugar isomerization in C-glycosylflavones. In usual solvent systems, α-anomers are easily separated from β-anomers, whereas corresponding pyranosyl and furanosyl anomers are not. However, they are easily separated after permethylation and characteristic features are found in the mass spectra of PM 6-C-arabinofuranosyl isomers. 相似文献
172.
The structure of a novel abscisic acid metabolite isolated from cell suspension cultures of Nigella damascena fed [2-14C]abscisic acid was iden 相似文献
173.
Light- and cytidine-dependent phosphatidylinositol synthesis in photoreceptor cells of the rat 总被引:2,自引:0,他引:2
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S Y Schmidt 《The Journal of cell biology》1983,97(3):832-837
Incorporation of [3H]inositol into phosphatidylinositol (Pl) in isolated rat retinas is enhanced by light and by the addition of cytidine to the incubation media. In retinas preincubated with [3H]inositol in dark, [3H]inositol was chased into Pl in light by addition of unlabeled cytidine and was chased out of Pl in light by addition of unlabeled cytidine plus inositol. Autoradiograms of retinas show a heavy density of silver grains over photoreceptor cell inner segments (with chase-in) and a loss of labeling (with chase-out). Exogenous cytidine and inositol were shown to enhance not only the turnover of Pl within photoreceptor cells but the synthesis of Pl as well; in media supplemented with these precursors, approximately 50% of [14C]glycerol and 25% of [32Pi]incorporated into lipid in light were associated with Pl. These results suggest that availability of both cytidine and inositol may play a role in the light-dependent changes in Pl metabolism within photoreceptor cells. 相似文献
174.
A transposable element, Tn2401, was found in a clinical isolate of Pseudomonas aeruginosa. Tn2401 had a size of 7190 nucleotides and encoded aminoglycoside 3'-phosphotransferase and aminoglycoside 6'-N-acetyltransferase. The sequence encoding the former enzyme was homologous with that of Tn903. Pseudomonas aeruginosa strains harbouring this transposon were resistant to kanamycin, neomycin, lividomycin, ribostamycin, paromomycin, netilmycin, tobramycin, dibekacin, gentamicin, sisomicin, and butirosin. 相似文献
175.
Östermann Elisabeth Sternberger Nancy H. Sternberger Ludwig A. 《Cell and tissue research》1983,228(3):459-473
Among a total of 135 tissue-reactive monoclonal antibodies previously prepared, 81 were brain-selective and were classified into neuronal and non-neuronal categories. The neuronal antibodies were again subdivided into antineurofibrillar, antiperikaryonal-neurofibrillar, and antisynapse-associated groups. On the basis of morphologic, developmental, biochemical, and pathologic criteria, the antibodies in at least two of these groups were found to detect heterogeneous antigens (called "neurotypes") rather than different antigenic determinants in single antigens. On examining the distribution in peripheral organs of staining patterns of 11 antineuronal brain-reactive antibodies, we now confirm that these antibodies are, indeed, largely brain-specific. In general, non-neuronal elements in liver, lung, heart, thymus, intestine, adrenal, and spleen remained unstained. However, most of the antibodies stained peripheral neural elements. Occasional antibodies did stain selected, non-neuronal structures. Four out of five antineurofibrillar antibodies stained nerve fibers in adrenal medulla, intestine and thymus. All of three antiperikaryonal-neurofibrillar antibodies also stained nerve fibers in the adrenal medulla, but not in other organs. Two out of three antisynapse-associated antibodies stained what appear to be nerve contacts on adrenal medullary cells, but not on any other peripheral cells examined. The non-neuronal peripheral staining patterns were restricted to selective nuclear staining exhibited by two out of five antineurofibrillar antibodies and the staining of macrophage and selected cardiac muscle nuclei by two of three antisynapse-associated antibodies. However, one antineurofibrillar antibody also stained the cytoplasm of selected liver cells. Among non-neuronally reacting antibodies, two antibodies stained nuclei of all cells except neurons in brain as well as peripheral organs. An antibody staining the ciliary epithelium of choroid plexus also stained basal bodies of ciliated bronchial epithelium. The overall data suggest that the specificity of brain-reactive antibodies is high and that their cross-reactivity with epitopes in non-nervous tissue is rare. In these cases, the antibodies seem to provide specific reagents for these additional structures as well as for their specific brain antigens. 相似文献
176.
Alkylsulfonic acids and some S-containing detergents as sulfur sources for growth of Chlorella fusca
Chlorella fusca can utilize the following substances as sole sulfur sources for growth: C1 to C8 n-alkane-1-sulfonates, linear alkylbenzenes sulfonates (LAS), -sulfonated fatty acid esters, polyethylene glycol sulfate and alkylsulfates. Good sulfur sources are alkylsulfonic acids, which are comparable to sulfate. Ethanesulfonic acid was used for comparison of the growth on sulfate and on a sulfonic acid, because best growth was achieved on this C2-sulfonic acid.Growth data of Chlorella on the enviromental important detergents linear alkylbenzene sulfonic acids, -sulfonated fatty acid methylester, Texapon and Sulfopon are presented. So far only microorganisms have been discussed as a source for degradation of sulfonic acids and detergents. It is suggested that green algae could be of similar importance for the biodegradation of these compounds.Abbreviations LAS
Linear alkylbenzene sulfonate
- ES
-sulfonated fatty acid methylester
- DTE
dithiocrythritol 相似文献
177.
The genes coding for 4 snRNAs of Drosophila melanogaster: localization and determination of gene numbers. 总被引:7,自引:5,他引:2
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H P Saluz T Schmidt R Dudler M Altwegg E Stumm-Zollinger E Kubli P S Chen 《Nucleic acids research》1983,11(1):77-90
Four small nuclear RNAs (snRNAs) have been isolated from Drosophila melanogaster flies. They have been characterized by base analysis, fingerprinting, and injection into Axolotl oocytes. The size of the molecules and the modified base composition suggest that the following correlations can be made: snRNA1 approximately U2-snRNA; snRNA2 approximately U3-snRNA; snRNA3 approximately U4-snRNA; snRNA4 approximately U6-snRNA. The snRNAs injected into Axolotl oocytes move into the nuclei, where they are protected from degradation. The genes coding for these snRNAs have been localized by "in situ" hybridization of 125-I-snRNAs to salivary gland chromosomes. Most of the snRNAs hybridize to different regions of the genome: snRNA1 to the cytological regions 39B and 40AB; snRNA2 to 22A, 82E, and 95C; snRNA3 to 14B, 23D, 34A, 35EF, 39B, and 63A; snRNA4 to 96A. The estimated gene numbers (Southern-blot analysis) are: snRNA1:3; snRNA2:7; snRNA3:7; snRNA4:1-3. The gene numbers correspond to the number of sites labeled on the polytene salivary gland chromosomes. 相似文献
178.
Heat Resistance of Spores of Marine and Terrestrial Strains of Clostridium botulinum Type C 总被引:1,自引:0,他引:1
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Resistance to heat of spores of marine and terrestrial strains of Clostridium botulinum type C in 0.067 m phosphate buffer (pH 7.0) was determined. The marine strains were 6812, 6813, 6814, and 6816; the terrestrial strains were 468 and 571. The inoculum level equaled 10(6) spores/tube with 10 replicate tubes for each time-temperature variable. Heating times were run at three or more temperatures to permit survival of some fraction of the inoculum. Survivors were recovered at 85 F (30 C) in beef infusion broth containing 1% glucose, 0.10% l-cysteine hydrochloride, and 0.14% sodium bicarbonate. D values were calculated for each fractional survivor end point after 6 months of incubation. Thermal resistance curves were constructed from the D value data. D(220) (104 C) values for spores of 468 and 571 equaled 0.90 and 0.40 min, respectively. The corresponding values for spores of 6812, 6813, 6814, and 6816 were 0.12, 0.04, 0.02, and 0.08 min. The z values for the thermal resistance curves ranged from 9.0 to 11.5 F (5.0 to 6.2 C). 相似文献
179.
Zusammenfassung Am Leitdamm des Jadebusens lebt Pycnogonum litorale im Lückensystem des Miesmuschelbesatzes. Dieser bietet mit hartem Untergrund, hoher Feuchtigkeit bei Niedrigwasser, genügend Actinien als Nahrung und guter Durchströmung bei gleichzeitigem Schutz vor Vertragung—offensichtlich günstige Lebensbedingungen für Pycnogonum litorale.Der Eiablage im Februar geht eine Reiterstellung des Männchens auf dem Weibchen von durchschnittlich 24 Tagen voraus. Unter künstlichen Kurztagbedingungen kann diese Reiterstellung auch außerhalb der Fortpflanzungsperiode eingenommen werden. Die Eier werden durch Rumpfbewegungen beider Partner zu den Ovigeren des Männchens bewegt. Bei 12°C schlüpfen die Larven etwa 41 bis 46 Tage nach der Eiablage aus, bei 19°C, im Sommer, schlüpften keine Larven.Im Jadebusen leben die Larven etwa 1/2 Jahn endoparasitisch in Hydrozoen. Die an die Metamorphose anschließende juvenile Phase, in der die Tiere frei leben, dauert ein knappes Jahr, die Reifehäutung erfolgt normalerweise im Sommer des zweiten Jahres, die Fortpflanzungsperiode etwa 6 Monate später, im Winter.
Mit Unterstützung der Deutschen Forschungsgemeinschaft. 相似文献
Observations on the life biology of Pycnogonum litorale (Ström) (Pantopoda)
Summary Pycnogonum litorale lives in an interstitial system, of the mussel zone on the embankment of the Jadebusen. Hard substrate, high humidity at low tide, sufficient Metridium senile as food, and active currents together with protection from drifting, constitute favourable conditions for this pycnogonid.Prior to laying egg in February, the male remains in a riding position upon the female for approximately 24 days. Under artificial short-day conditions the riding position may also be assumed outside of the reproductive period. The eggs are transported to the ovigers of the male by trunk movements of both partners. At 12°C the larvae hatch about 41–46 days after egg-laying. No larvae hatched from eggs laid during summer at 19°C.The larvae live endoparasitically in Hydrozoa for about 1/2 year. Following metamorphosis, the freeliving juvenile phase lasts barely a year. The maturation moult normally takes place in the summer of the second year, the reproductive period beginning about 6 months later, in winter.
Mit Unterstützung der Deutschen Forschungsgemeinschaft. 相似文献
180.
Gerhard H. Schmidt Erich Gürsch 《Ethology : formerly Zeitschrift fur Tierpsychologie》1971,28(1):19-32
Die während des Einspinnvorganges ablaufenden Verhaltensweisen werden bei Formica pratensis Retz. genau untersucht und mit anderen Ameisenarten verglichen.
- 1 Die Larve führt vor der Sekretabgabe Suchbewegungen aus, wodurch die Pflegerinnen veranlaßt werden, sie in vorher zusammengetragenes, feines Nestmaterial zu legen. Hier läßt sie eine Mulde entstehen, die ihr die Orientierung beim Kokonbau erleichtert.
- 2 Zum Kokonbau ist Nestmaterial unbedingt erforderlich; Licht als nestfremder Faktor verhindert die Gespinstanfertigung nicht.
- 3 Beim Kokonbau lassen sich drei Phasen unterscheiden: a) Anlage des Gerüstes durch Verbindung einzelner Nestpartikel zu einem strumpfförmigen Gebilde; b) Anfertigung des Außenkokons durch Abdichten der im Gerüst vorhandenen Poren; c) Bau des Innenkokons durch Spinnen von Achtertouren, wobei zunächst ein Kokonpol mit der dazugehörigen Kokonhälfte angefertigt wird und erst nach Drehung urn die Querachse der andere Pol.
- 4 Drehbewegungen um Quer- und Längsachse kommen in alien Phasen des Kokonbaues vor.
- 5 Die Achtertour wird regelmäßig durch eine Absteifbewegung, die der Formung des Kokons dient, unterbrochen.
- 6 Das plastische Verhalten der Larven beim Kokonbau wird aufgezeigt. Die Verhaltensweisen werden anhand eines Reiz-Wirkungsschemas diskutiert.