Le développement des ovaires des ouvrières des abeilles et l'ectohormone des reines

Zusammenfassung Die vorliegende Arbeit soll die Begriffe der «Fruchtbarkeitssubstanz» und des «hemmenden Ektohormons» näher bestimmen. Nach unserer Ansicht können aktivierende und hemmende Faktoren einander entgegengesetzte Wirkungen haben. Das Vorhandensein einer Fruchtbarkeitssubstanz bzw. eines trophischen Faktors geht aus unseren Versuchen ebenso wie aus denjenigenMüssbichlers hervor; dies steht aber nicht im Gegensatz zur Wirkung des hemmenden Faktors, der aus dem Tegument der Königin gewonnen werden kann. Auf Filterpapier dargeboten lösen diese Tegumentextrakte ein charakteristisches Verhalten der Arbeitsbienen aus (Antennenbewegungen, Strecken des Rüssels). Die Reizung der Antennen, die mit der oralen Aufnahme des Ektohormons verbunden ist, scheint für die Hemmung der Ovarialentwicklung bei Arbeitsbienen notwendig zu sein.     

Adénosine triphosphatase et pyrophosphatase des chloroplastes

Summary ATP hydrolysis and inorganic pyrophosphate hydrolysis in chloroplasts of spinach leaves are characterized by a different pH optimum, a different sensitivity to magnesium ions, top-chloromercuribenzoate and to ageing. It is concluded that ATP and inorganic pyrophosphate are likely hydrolyzed by two different enzymes in chloroplasts.     

Relations entre les taux cétoniques du plasma et des organes

Summary Ketone levels in the rat's organs (liver, muscle, lung, kidney, brain) do not seem to be correlated with the ketone level in the blood plasma. On the other hand, there are significant and high correlations between the ketone levels of different organs. These findings are not inconsistent with the generally accepted theory according to which blood distributes hepatic ketone bodies to the periphery. But ketone levels of the organs seem to be regulated not by variations of the plasma ketones, but by another common factor. At present, it is impossible to say how this regulation is effected.     

Préparation des sous-unités de la dopamineβ hydroxylase humaine et des anticorps anti-sous-unités

Summary The present study deals with the dissociation of human dopamine hydroxylase (DBH) in subunits with a mol. wt of 79,500, and the preparation of specific antibodies in rabbits. No cross-reactivity was observed between human DBH and antibodies against human DBH subunits.

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Nous remercions Madame M. Le Maout pour son excellente aide technique.

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Ce travail a bénéficié de l'aide de l'INSERM (contrat no 75.4.161.2).     

Photolyse ultraviolette et photoréactivation des bactéries — Aspects de dépolymérisation et repolymérisation des acides nucléiques bactériens

Summary Electrophoretic analysis of bacterial substance proves the departure, from UV irradiated microbes screened from light for a certain time, of substances which were responsible for increasing the charge density by surface unit during the first moments which follow the irradiation by UV rays. Spectrophotometric analysis of liquids having contained these bacilli proves concommitantly the diffusion of those substances from the bacterial substance to the aqueous phase and reveals their nature. The photoreactivity which is possible during the first moments following the UV irradiation of bacilli, due to the presence of the fragments of depolymerisation of nucleic acid macromolecule in the bacterial substance, becomes impossible after the departure (diffusion) of those fragments to the aqueous phase. These observations seem to show that the phenomenon of photo-reactivity is connected with the repolymerisation of the macromolecule primitively divided of desoxyribonucleic acid.     

La libération des deux acides nucléiques au cours de l'autolyse des bactéries et sa signification

Summary The existence of a process of directed mutation for aBacterium coli through the action of the desoxyribonucleic acid released by anotherBacterium coli during its autolysis raises the question of the behavior of the two sorts of nucleic acids during the autolytic desintegration of the bacterial cell. Working with several germs, we have seen that autolysis releases a nucleoproteidic fraction containing from 20 to 30 per cent of nucleic acid. The desoxyribonucleic acid represents 50 to 70 per cent of the total nucleic acid; this value is very much higher than that of the initial germs, which contain but 20 to 30 per cent. The signification of the easy mobilization of the desoxyribonucleic acid by autolysis is discussed, according to the observations made in usingRobinow's method of nuclear staining.     

Effet cytologique des traitements mécanique et ultrasonique sur quelques bacilles aérobies

Zusammenfassung Ultraschall-Behandlung der in Ketten gewachsenen aeroben Bazillen spaltet vorerst die Querwände des Zellverbandes, wodurch in 60 s intakte, monozellulare Formen entstehen. Die « vegetative » Zellwand wird erst nach einigen Minuten geschädigt; sie wird dann je nach Spezies in 20–60 min mehr oder weniger aufgelöst, wobei die Kapsel weder bei der Mickle- noch bei der Überschallbehandlung nennenswerte Schutzwirkung entfaltet. Die von den vegetativen Zellresten befreiten, bakteriellen Endosporen bleiben bei der Ultraschall-Behandlung, im Gegensatz zur Mickle-Behandlung, selbst nach 2 h intakt; ihr Exosporium wird aber nach etwa 1 h aufgelöst. Diese Beobachtung ermöglicht die Isolierung des Exosporiums und das serologische und chemische Studium dieser bisher nicht klar definierten Sporensubstanz. Durch alternierende Behandlung: Ultraschall-Mickle-Ultraschall kann auch die Sporenwand, frei vom Exosporium, in Lösung gebracht werden.

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Travail effectué avec l'aide du Fonds de recherches Hans Buess.     

Relations entre oxydation phosphorylante et structure des mitochondries hépatiques de rats carencés en vitamines B1 et B2

Summary In the experimental B₁-avitaminosis a decrease of oxidative ATP-resynthesis in liver homogenates, and a significant diminution of the optical density of mitochondrial suspension were simultaneously observed: in other words a probable parallelism in the alteration of function and structure. In ariboflavinosis neither oxidative phosphorylation nor optical density seems to be notably impaired, but the nitrogen content of mitochondrial suspensions decreases significantly. Therefore this second type of avitaminosis would appear to affect the mitochondrial population rather than energetic metabolism or structural integrity of the protoplasmic granules.

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Communication présentée au 3^e Congrès International de Biochimie, Bruxelles 1955.     

Observation et étude quantitative de corpuscules d'aspect virusal dans des cultures de sarcome de Rous

Zusammenfassung In vitro gezüchtete Zellen des Rous'schen Sarkoms wurden der Wirkung von Röntgenstrahlen und radioaktivem Alkohol (CH₃C¹⁴H₂OH) ausgesetzt und darauf elektronenoptisch untersucht. In einem geringen Prozentsatz der untersuchten Kulturen (9,5%) konnten virusartige Partikelchen von 60 bis 90 mµ Durchmesser intra- oder extrazellulär dargestellt werden, die mit den vonClaude, Porter undPickels gefundenen identisch sind und wahrscheinlich dem Rousschen Virus zugeordnet werden können. Es wurden Kolonien von solchen Gebilden intrazytoplasmatisch in Form von Einschlusskörperchen beobachtet. Auch unbestrahlte Kontrollen von Sarkomzellen wiesen Viruskörperchen auf, wenn auch bisher in geringerem Prozentsatz.Es ist vorderhand noch unsicher, ob der Bestrahlung eine primäre Rolle in der Darstellbarkeit dieser Viren zukommt.     

Létalité et anomalies du développement embryonnaire dans la descendance des femelles triploïdes de l'Amphibien UrodèlePleurodeles waltlii Michah

Summary A comparison is made between aneuploid off-springs of triploid females mated with diploid or triploid males ofPleurodeles waltlii. In the latter case, embryonic lethality is raised, and abnormalities are more severe. The disturbances affect morphogenesis, embryonic growth and physiological differentiation. At the cellular level, nuclear and nucleolar degenerative changes are conspicuous.     

Inhibition sélective des «vraies» et «pseudo»-cholinestérases du rectus de grenouille

Summary The hydrolysis of acetylcholine chloride (0.01M) by frog's rectus extracts, is inhibited by low concentrations of 3318 CT (CI-50 3.2×10^–7) and high concentrations of D.F.P. (CI-50 1.3×10^–5). Inversely, the hydrolysis of butyrylcholine perchlorate is inhibited by low concentrations of D.F.P. (CI-50 3×10^–9) and high concentrations of 3318 CT (CI-50 3×10^–4). Both are inhibited by similar concentrations of neostigmine (CI-50 1.1×10^–7 and 1.5×10^–7). Frog's rectus thus contains true and pseudo-cholinesterases. The inhibitions produced by D.F.P. added to the muscle itself (and not the extract) correlates well with the potentiation of the corresponding ester. Sensitization to AcCh and to BuCh appears to be specifically related to the inhibition of Ac ChE for the former ester, of XChE for the second one.     

Un dispositif sensible pour la mesure rapide d'attractions et de répulsions tropistiques chez des animaux grégaires

Zusammenfassung Nach der Methode vonViaud zur Bestimmung der Verschiebung des Schwerpunktes von Tiergruppen unter dem Einfluss eines Stimulus, wird eine neue Apparatur beschrieben, die gestattet, die Abstossung oder die Anziehung bei Schwarm oder Gruppen bildenden Formen (animaux grégaires) rasch und genau zu messen. Die Apparatur funktioniert halbautomatisch, und die mittlere Verschiebung des Schwerpunktes der Tiergruppe wird mit Hilfe einer elektrischen Integration direkt bestimmt.     

Effet du fluoroacétate et des rayons X sur la teneur en acide citrique du foie de la souris

Summary In contrast to rats, male mice injected with sodium fluoroacetate accumulate citrate in their livers, whereas females do not. Whole-body irradiation reduces the level of accumulated citrate in the liver as well as in other tissues of the mouse.     

Cytologie comparée des Muridae. L'origine des Ellobii

Summary (1) The present paper deals with the chromosomial cytology of 11 species and underspecies ofMuridae. (2) The diploïd number being the same (2N=42), there are striking differences between two species ofBandicota, B. indica showing about 20 big metacentric chromosomes which are lackingB. bengalensis. (3)Meriones blackleri is characterized by 72 chromosomes, the species previously described possessing either 44 or 60 elements. (4) The study ofPhenacomys ungava confirms the view that 56 (54) is the primitive number in theMicroti. There is an interesting parallelism between the morphological and the cytological data. (5) A missing link betweenMicroti andEllobii has been found inMicrotus oregoni which possesses 17 chromosomes, its digamety belonging to the typeX-O, X-X. (6) Owing to the fact thatM. oregoni is more fossorial than the otherMicrotus, it is a morphological intermediate betweenMicroti andEllobii. (7) The genusChilotus (Baird) is also fully valid.     

Biosynthèse des hormones stéroïdes

Summary The different pathways of biosynthesis are described, by which steroid hormones are producedin vivo in the gonads, the adrenal cortex and the placenta, orin vitro by corresponding tissue preparations. First of all a short outline of the origin of cholesterol from acetyl coenzyme A through the biological isoprene unit, the pyrophosphate of ³-iso-pentenol, through squalene, lanosterol and zymosterol is given. Partial side-chain degradation of cholesterol, where ACTH plays an important role, leads to pregnenolone and further to progesterone.The latter compounds are the starting material for the other steroid hormones. On the one hand, they are converted in the gonads and adrenals into 17-hydroxy derivatives, in which the side chain is completely removed by enzymes of the said and also of non-endocrine tissues, to form the androgens. Furthermore the adrenals produce their own typical androgens. After hydroxylation of the angular 19-methyl group, androgens are aromatised to estrogens.On the other hand, the adrenal converts progesterone by hydroxylation in 21- and, depending on the case, also in 11- and/or 17-position into the classical adrenocortical hormones. The special feature of an 18-hydroxylation and -dehydrogenation forms part of the biogenesis of aldosterone; a new example is given for the methods used towards its elucidation, consisting in the biosynthetic conversion of progesterone into two virtual intermediates, 18-oxo-progesterone and 21-desoxyaldosterone, which already contain the 18-aldehyde group, characteristic for aldosterone.The regulation of the biogenesis of the different hormones is mentioned and compounds are discussed which block one or other of the biosynthetic steps.

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D'après une conférence faite aux VIes Journées biochimiques latines, Genève (Suisse), 25 mai 1961.

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Publication No. 179Über Steroide. Communication No. 178 voirK. Heusler, P. Wieland etA. Wettstein, Helv. chim. Acta, sous presse.