Keine Mutationsauslösung durch 5-Äthyl-2′-desoxyuridin (ÄDU) bei Drosophila melanogaster

Summary The rate of sex-linked recessive lethals as well as of translocations between 2^nd and 3^rd chromosome was determined in a multipurpose strain ofDrosophila melanogaster after intraperitoneal injection of 5-ethyl-2-deoxyuridine. No mutations, however, were observed after that treatment. These findings confirm the results of other investigators with T-2-phages and are in good agreement with theoretical considerations.     

Selective purification of the thiol peptides of myosin

1. A method for selective purification of thiol peptides is described. Thiol groups in a protein are treated with radioactive cystine by disulphide-thiol interchange. The labelled cystine peptides in a digest can then be fractionated for peptide ;maps'. Performic acid oxidation of paper strips containing the radioactive peptides followed by further ionophoresis yields the purified cysteic acid peptides. 2. The thiol peptides in a peptic digest of cystine-exchanged myosin were purified in this way, and their amino acid sequences were determined. 3. The conclusion that myosin contains at least 16, and probably between 20 and 22, unique thiol sequences indicates that the molecule consists of two chemically equivalent components.     

Fatty acids synthesis in rat adipose tissue. Tracer concentration effects in vitro

1. The use of labelled acetate for studying the synthesis of long-chain fatty acids in rat adipose tissue in vitro has been examined, with special reference to the effect of acetate concentration. 2. The incorporation of acetate into fatty acids is proportional to the concentration of acetate in the medium when the latter does not exceed about 10mum. Above this concentration, the relative incorporation becomes progressively less, and reasons for this are discussed. 3. In particular it is shown that this is not necessarily due to disturbance of the endogenous rate of fatty acid synthesis by a relatively large amount of acetyl-CoA derived from added acetate. 4. However, to ensure that the added acetate does not cause such a disturbance its concentration must be kept sufficiently low. For labelled acetate used under present conditions, this concentration should not be more than about 10mum.     

Zur Kenntnis der cellulolytischen Aktivität in der Gattung Ganoderma (Lackporlinge)

Zusammenfassung Ganoderma resinaceum und Ganoderma pfeifferi verfügen über ein Enzymsystem, das Carboxymethylcellulose und Cellulosepulver anzugreifen vermag; beide Pilze dürfen danach als cellulolytisch aktiv bezeichnet werden. Ganoderma lucidum erweist sich dagegen als cellulolytisch inaktiv. Carboxymethylcellulose wird nur in verschwindend geringer Menge abgebaut und dies nur in Verbindung mit einer organischen N-Quelle; Cellulosepulver wird überhaupt nicht angegriffen.

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On the cellulolytic activity of some species of the genus Ganoderma

Summary Three wood-destroying fungi of the white-root type, Ganoderma resinaceum, Ganoderma pfeifferi and Ganoderma lucidum are tested in their cellulolytic activity. Ganoderma resinaceum and Ganoderma pfeifferi produce an extracellular enzyme system, that degrade Carboxymethylcellulose and insoluble cellulose powder. Ganoderma lucidum degrades Carboxymethylcellulose in a very small extent and only in presence of organic nitrogen sources; cellulose powder was not attacked.

     

A pattern recognition machine

Summary A new probabilistic learning machine for pattern recognition is described. The machine operates on the basis of random criteria obtained from special pseudorandom generators. The input, particularly versatile due to the use of an image dissector, allows a random scan for which normal television storage pick-up tubes are not suitable. The computation data section, completely automatic, uses two ferrite core memories with a capacity of 64,000 bits. Consequently it is possible to obtain very quick recognizing cycles for a maximum of 16 classes of 256 learning examples each. Preliminary experiments are reported, some of which, like the recognition of meteorological events by the analysis of absolute baric topography maps, could already be suitable for practical application of the machine.This work was supported by Consiglio Nazionale delle Ricerche (C.N.R.) through the Gruppo Nazionale Cibernetica (G.N.C.).