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1.
Zusammenfassung Die cancerostatischen Viscum-Proteine induzieren im Tierversuch mit geringsten Dosen eine Proliferation des Thymus und verhindern prophylaktisch das Angehen von Tumoren. Höhere Dosen zerstören dagegen den Immunapparat durch Überbeanspruchung und die Tumorhemmung bleibt aus.

We are indebted to the Deutsche Forschungsgemeinschaft for financial support (M. St.) and for granting a Forschungsfreijahr (F. V.).  相似文献   

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Summary N, N, N, trimethyllysine and an unidentified methylated amino acid which co-electrophoresed and cochromatographed with the hydrolysis product of S-adenosyl-L-methionine, occur in fetal canine cardiac myosin and are isotopically labeled in vitro with S-adenosyl-L-(methyl3H) methionine between the 10th and the 12th day of culture.  相似文献   

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Summary Visual pigment was extracted from a fresh water toleost,Etroplus suratensis and the optical density measured over a range of 300–650 nm. The absorption spectrum indicates the max at 550 nm and a small hump at 530 nm. Through partial bleaching at 630 nm, it was confirmed that the fish possesses a mixture of 2 visual pigments: the one with the max at 550 nm predominating over the other.  相似文献   

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Summary The conversion of cholesterol into 19-nor-5-cholestan-3-ol by the spongeAxinella polypoides involves a partial loss (40%) of the 3-hydrogen atom; moreover administration to the sponge of [4-14C]cholesterol tritiated at C-4 and C-7 showed that the 4- and 7-hydrogen atoms are retained in this conversion. A competitive uptake experiment, [4-14C]cholesterol vs. [7-3H2]5-cholestanol, showed that the sponge utilized exclusively cholesterol for the production of 19-nor-5-cholestan-3-ol.Part of this work has been presented at the Nato Conference on Marine Natural Products (Jersey, Great Britain, October, 1976).-This contribution is part of the Programma finalizzato Oceanografia e Fondi marini-sottoprogetto Risorse biologiche C.N.R. Italy.  相似文献   

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Summary In inbred mice possessing high and low tissue superoxide dismutase (SOD) activity, it was observed that the difference in the SOD activities of the liver homogenates during development attains the maximum characteristic of the strain by about the 150th day. Subsequently, the SOD activity change displays a tendency in contrast with the age and the basic state. In the course of the development, a difference was also observed between the 2 mouse strains in the lipid peroxidation variation.Part XVIII of the series Properties of enzymes.  相似文献   

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a aaa a aa aa a a E. coli aa, a aa aa a , a a aa - a .

Laboratory of Biological Investigations.

Laboratory for Chemistry of Antibiotics.  相似文献   

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Summary [1-N4-Dimethyl-asparagine]-angiotensin II was synthesized by Merrifield's solid-phase procedure. The analogue gave rat blood pressure about 70% relative potency to Hypertensin (Ciba). Rabbit aorta strips gave intrinsic activity E=1, a PD2 of 6.92±0.09 and an affinity relative to [Asn1]-angiotensin II of 6.5%.The editors do not hold themselves responsible for the opinions expressed in the authors' brief reports. — Les auteurs sont seuls responsables des opinions exprimées dans ces brèves communications. — Für die Kurzmitteilungen ist ausschliesslich der Autor verantwortlich. — Per le brevi comunicazioni è responsabile solo l'autore. — . — Solo los autores son responsables de las opiniones expresadas en estas comunicationes breves.Acknowledgment. The authors wish to express their appreciation to Dr Emanuel Escher, School of Medicine, Centre Hospitalier Universitaire, Sherbrooke, Quebec, for his help in providing the biological data and critical comments.  相似文献   

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Summary The correlation between 3,5, c-AMP levels, TSH content and secretion of separated thyrotropic cells was studied. Incubation of the separated cells with 1, 10 and 100 ng of TRH does not change the 3,5, c-AMP levels, despite the significant rises of the TSH level. Dibutyryl c-AMP causes rise in TSH content, with no indication of its secretion. PGE2 10–5 increased 3, 5, c-AMP levels with no change in the content or secretion of TSH in separated thyrotropic cells.  相似文献   

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Protein aggregation is a notable feature of various human disorders, including Parkinsons disease, Alzheimers disease and many others systemic amyloidoses. An increasing number of observations in vitro suggest that transition metals are able to accelerate the aggregation process of several proteins found in pathological deposits, e.g. -synuclein, amyloid (A) peptide, 2-microglobulin and fragments of the prion protein. Here we report the effects of metal ions on the aggregation rate of human muscle acylphosphatase, a suitable model system for aggregation studies in vitro. Among the different species tested, Cu2+ produced the most remarkable acceleration of aggregation, the rate of the process being 2.5-fold higher in the presence of 0.1 mM metal concentration. Data reported in the literature suggest the possible role played by histidine residues or negatively charged clusters present in the amino acid sequence in Cu2+-mediated aggregation of pathological proteins. Acylphosphatase does not contain histidine residues and is a basic protein. A number of histidine-containing mutational variants of acylphosphatase were produced to evaluate the importance of histidine in the aggregation process. The Cu2+-induced acceleration of aggregation was not significantly altered in the protein variants. The different aggregation rates shown by each variant were entirely explained by the changes of hydrophobicity or propensity to form a structure introduced by the point mutation. The effect of Cu2+ on acylphosphatase aggregation cannot therefore be attributed to the specific factors usually invoked in the aggregation of pathological proteins. The effect, rather, seems to be a general related to the chemistry of the polypeptide backbone and could represent an additional deleterious factor resulting from the alteration of the homeostasis of metal ions in cells.Received 4 December 2003; received after revision 7 January 2004; accepted 3 February 2004  相似文献   

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Summary Some compounds containing piperidine rings have been synthesized, and submitted to biological tests on insects for their hormonal activity on pupae ofTenebrio molitor L. andBombyx mori L. Some of them display a hormoneanalogue or toxic activity.The editors do not hold themselves responsible for the opinions expressed in the authors' brief reports. — Les auteurs sont seuls responsables des opinions exprimées dans ces brèves communications. — Für die Kurzmitteilungen ist ausschliesslich der Autor verantwortlich. — Per le brevi comunicazioni è responsabile solo l'autore. — . — Solo los autores son responsables de las opiniones expresadas en estas comunicationes breves.This research has been supported by the Italian National Research Council (CNR) special ad hoc program Fitofarmaci e Fitoregolatori, Subproject. 7.Acknowledgments. We thank Prof. G. Jommi for helpful discussions related to this and previous articles on the same subject.  相似文献   

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Summary On treatment of 3-hydroxy-5-steroids with lead tetra-acetate formation of 3, 9-oxides is observed. The yields of this ring closure reaction decrease significantly in the order 11-keto, 9, 11-ene and ring-C saturated compounds.  相似文献   

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We tested the sexual responsiveness of female canaries,Serinus canaria, to two sets of different types of male conspecific songs. In each set, three of the male songs had been recorded in a young bird which was isolated at an early age from conspecifics. Each bird was recorded during three stages of the song ontogeny (early plastic songs, late plastic songs and crystallized songs). We used copulation solicitation displays (CSD) as an index of female sexual response. Playbacks were performed during a period of natural sexual responsiveness of the females to song. We demonstrated that, in both experiments, very weak sexual displays of female canaries were recorded to the two stages of isolate plastic songs. Each of the two different types of isolate crystallized songs elicited high levels of CSD. These levels are not significantly different from the adult domesticated control song. Taken together, these results suggest that even isolate songs may convey sexual information. We discuss prominent acoustic features that must be present to ensure female sexual responses.  相似文献   

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