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11.
Oxygen-evolving photosystem II-phycobilisome particles froma red alga were inhibited 50–80% by aging, dilution, lowpH and salt-washing. Bovine serum albumin, and dithiothreitolwere found to stimulate activity in all but salt-washed particles.CaCl2 and MnCl2 partially restored activity lost after agingor dilution. 1Current address: Waksman Institute of Microbiology, RutgersUniversity, Piscataway, New Jersey 08854-0759, U.S.A. (Received October 5, 1985; Accepted March 31, 1986)  相似文献   
12.
Conjugates of prostaglandins and thromboxanes with tritium labeled amino acids were prepared and employed as labeled ligands in porstaglandin and thromboxane radioimmunoassays. Assays for PGF, 15-keto-13, 14-dihydro-PGF, TXB2 and 15-keto-13, 14-dihydro-TXB2 were evaluated in comparative studies using either these heterologous ligands or the corresponding homologus tritiated eicosanoid as tracers. Binding properties for the respective antibodies were found to be similar using either tracer.Three biological studies were also conducted, viz. study of the release of TXB2 during collagen induced platelet aggregation, of 15-keto-13, 14-dihydro-TXB2 during guinea pig pulmonary anaphylaxis, and of PGF (measured as 15-keto-13, 14-dihydro-PGF in peripheral plasma) during bovine luteolysis. The analyses gave comparable results using either the heterologous or the homologous assay.Thus, this type of labeled prostanoid conjugates may serve as a convenient alternative to homologous tracers in radioimmunoassay. Heterologous tracers may even in certain cases provide the only simple solution to the problem of preparing a labeled ligand of high specific activity.  相似文献   
13.
Summary The quantitative imaging of lithium distribution, in histological sections of 15-days old mouse embryos (whose mother had been submitted to Li-treatment), was performed using6Li isotope as tracer,6Li(n,)3H nuclear reaction for detection, and dielectric track detectors. Despite the particular difficulties of cryosectioning the embryos without disturbing the lithium distribution, the Li regionalization appeared to be very clear-cut. The ectomesodermic tissues were significantly more loaded with lithium than the endodermic ones. This is probably related to the ectomesodermic tissues being also those most sensitive to the teratogenic effect of lithium. The Li-distribution in the embryo brain was almost homogeneous, instead of being heterogeneous as in adult brain. The mean Li-concentration in the embryo brain was not much below the Li concentration in the grey matter of the mother brain, but it was significantly larger than that in the white matter of the mother brain. Our results are discussed in the context of teratogenic effects observed in situ during mammalian development.  相似文献   
14.
Summary DNA haplotype constellations of the β-globin gene cluster have been analyzed in German families with hemoglobinopathies (Hb Freiburg, Hb K?ln, Hb Presbyterian) and β-thalassemias. The polymorphis patterns obtained were compared to those found in families from Greece, Italy, and Turkey affected by β-thalassemia syndromes. With the combined analysis of seven restriction site polymorphisms a DNA-diagnostic prediction for additional offspring could be made with an overall frequency of 75% in the four ethnic groups.  相似文献   
15.
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   
16.
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   
17.
Zusammenfassung Die weiblichen Larven der heterogonen Gallmücke Heteropeza pygmaea (Syn.: Oligarces paradoxus) können milieuabhängig viviparpädogenetisch sowohl weibliche als auch männliche Nachkommen erzeugen.Das Divergieren der pädogenetischen Entwicklung von Weibchen und Männchen ist spätestens im Laufe der ersten Reifeteilung sichtbar: Bei Weibchen läuft nur eine, und zwar eine äquationelle Reifeteilung ab. Der nicht reduzierte Eikern enthält ungefähr 77 Chromosomen. Der einzige Richtungskern degeneriert in der Regel. Aus Eiern, in denen beide Reifeteilungen durchgeführt werden und der Chromosomensatz des Eikerns auf 38 oder 39 Chromosomen reduziert wird, entwickeln sich Männchen. Die drei Richtungskerne degenerieren nicht, sondern beteiligen sich an der Furchung.Die Männcheneier sind in der Regel schon vor der Metaphase der ersten Reifeteilung daran zu erkennen, daß sie größer sind als Weibcheneier gleichen Kernteilungsstadiums und außerdem eine im Verhältnis zur Nährkammer sehr viel größere Eikammer haben.Zwischen Meiose und erster Furchungsteilung der Männchen wird die Chromosomenzahl des reduzierten Eikerns aufreguliert, indem zwei oder mehrere somatische Kerne der Mutter mit dem Eikern verschmelzen. Diese somatischen Kerne wurden schon während der Meiose in der Eikammer beobachtet.In der zweiten bis vierten Furchungsteilung werden in Weibchen und Männchen Chromosomen aus den zukünftigen somatischen Kernen eliminiert (1. El.). Jeweils ein Kern jedes Embryos, der spätere Keimbahnkern, wird von dieser Elimination ausgenommen. Im Männchen ist dies stets ein Abkömmling des auf regulierten Kerns. Aus den anderen Abkömmlingen des aufregulierten Kerns werden die zur Aufregulation verwendeten Chromosomen der mütterlichen Somakerne eliminiert.In der sechsten bis achten Furchungsteilung wird in beiden Geschlechtern aus den künftigen somatischen Kernen ein einzelnes Chromosom eliminiert (2. El.). Danach enthalten die Somakerne die endgültigen Chromosomenzahlen: im Weibchen 10, im Männchen 5. Die Chromosomenzahl der Spermatocyten II beträgt 7.Meinem verehrten Lehrer, Prof. Dr. H. Ulrich, danke ich für die Anregung zu dieser Arbeit und den stets fördernden Einfluß, den er auf den Fortgang der Untersuchungen ausübte. Ich danke Herrn F. Würgler und Herrn Dr. W. Sautee für ihre Hilfe bei der Auswertung und meiner Mutter für ihre Unterstützung beim Verfassen des Manuskripts. Prof. J. Seiler und Prof. H. Bauer danke ich für ihre wertvollen Ratschläge.  相似文献   
18.
The Effects of Urethan and Hydroxyurethan on Transforming DNA   总被引:1,自引:0,他引:1       下载免费PDF全文
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19.
SUMMARY: The examination of 91 strains of heterofermentative lactobacilli and the subdivision of the groups by the chromatographic patterns is described. The overall assessment of differences suggests that division is arbitrary; however, selection of certain characters has produced a division which is in agreement with the previous biochemical grouping.  相似文献   
20.
Variations of the total free amino acid (FAA) pool and the content of specific amino acids have been measured in the muscle and hepatopancreas of adult shrimps, Penaeus japonicus, acclimatized at five water salinities: 38, 32, 26, 20 and 14%‰ The FAA content is always higher in muscle than in hepatopancreas at all tested salinites. On the other hand, the hepatopancreas exhibits the highest concentrations of essential amino acids. Two steps in the evolution of FAA content can be observed, the first one regarding decrease in salinity from 38 to 20%‰ and the second one, when salinity goes below 20%°. The first step can be characterized by a 16% decrease of total FAA content in the muscle and a 36% increase in the hepatopancreas. In muscle, the variations are mainly due to changes in non-essential FAA content, whereas in the hepatopancreas, they are linked to variations in essential FAA content. The other step is characterized by a drastic increase in moisture and decrease in FAA content in both studied organs when water salinity is 14%‰ The total FAA content is about 40% lower in shrimps at 14%° compared to 38%‰ seawater salinity. During adaptation, the FAA pool (mainly NEFAAs) of muscle seems to be directly related to osmoregulation, whereas in the hepatopancreas, its evolution seems to be linked with energy expenditure and protein synthesis. The results are evaluated in order to elucidate the role of FAA in intracellular osmoregulation and in relation to animal ecology.  相似文献   
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