Action de différents mélanges gazeux sur l'artère mésentérique de l'embryon de poulet explantée in vitro

Summary The effect of various gas mixtures on the mesenteric artery of chicken embryo explanted in vitro has been studied. The expiants were cultivated in normal air, with addition of 3% of CO₂, and in hypo- and hyperoxic atmosphere. The best survival of explanted arteries is obtained with atmospheric air. The hypoxic gas mixture (2% O₂) has the most toxic effect on the expiants. The hyperoxic conditions show also a toxic effect, but in a lesser degree than hypoxic conditions.

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Ces recherches ont été faites grâce à un subside du Fonds National Suisse de la Recherche scientifique et de la Fondation E. Barell.     

Regulation of ammonia uptake inAspergillus nidulans

Summary The ammonia uptake inA. nidulans was found to be linear for about 20 min, and was proportional up to 1.5 mg/ml dry cell density. The transport of ammonia does not involve energy. Normal and biotin deficientA. nidulans showed an identical K_m-values of 10.26×10^–5 M ammonia for uptake. The uptake of ammonium ion has been shown to be regulated by the intracellular concentration of ammonia.Acknowledgment. The award of research fellowship by the Govt of India, Department of Atomic Energy, Bombay, to JDD is acknowledged.     

Structure and assembly of the 20S proteasome

The barrel-shaped 20S proteasome is one of the two components of a larger 26S particle, the multicatalytic 2000-kDa protease complex. The proteolytic sites are located in the inner chamber of the 20S particle and are only accessible via narrow entrances. This paper reviews the current knowledge concerning proteasome formation, proteolytic activities, structural aspects and assembly. Eukaryotic proteasomes are made up by four rings each of which contains seven different subunits occurring at fixed positions. While the outer rings contain α-type subunits, the inner ones comprise β-type subunits. The current assembly model for eukaryotic 20S proteasomes is based upon the detection of 13S and 16S intermediates, respectively, in addition to previous findings with archaebacterial and eubacterial proteasome assembly. The available data suggest a cooperative assembly of the α-type and β-type subunits into half proteasome-like complexes followed by dimerization into proteasomes. During or after dimerization of half proteasomes, the β-type subunits are processed. The prosequence of the β-type subunits is essential for the assembly process and prevents protease activity of immature proteasomes.     

Les tests microbiologiques pour la détermination des vitamines

Summary The qualities required by a microorganism to work as test object are studied, so as the utilized methods to measure development.The different, watersoluble vitamins from the group B: thiamin, riboflavin, nicotinic acid, adermin (pyridoxin), pantothenic acid, -alanin, biotin, p-aminobenzoic acid, mesoinositol, enable the creation of a useful test with a selected microorganism.The problem of the vitaminic factors of the soil is one of those which can only be studied with help of microbiological tests. The presence of vitamins in the soil is proved. Their origin is discussed. Their action and that of vitamins voluntary added to the soil is studied. It is shown that the qualities of soil and manures have a marked influence on the thiamin rate of the studied plant.A cycle is suggested to show how the action of growth factors enable to understand the natural relations existing between the auxo-heterotrophic and the auxo-autotrophic organisms. The growth factors of the soil participate to the biological balance ruling life in and on the soil. The necessity of an ecological vitaminology is being considered.     

Composition of epicuticular wax of rice,Oryza sativa

Summary The epicuticular wax of rice, varietyRibe, comprised n-alkanes, esters, aldehydes and free alcohols. The nalkanes contained 4 major chain lengths, C₂₇, C₂₉, C₃₁ and C₃₃. Triacontanal and dotriacontanal were the major aldehydes. Octacosanol comprised 89% of the free alcohols. The esters were mainly esters of C₁₆ to C₂₄ acids with C₂₂ to C₃₀ alcohols.This research was supported by the Consiglio Nazionale delle Ricerche, Rome.     

Esterase activity in the hepatopancreas ofMacrobrachium lamarrei (Crustacea: Decapoda)

Summary The activity of the hepatopancreatic esterase of the fresh water prawnMacrobrachium lamarrei was optimal at pH 7.4 and temperature 40°C. The activity increased with the increase in incubation period and enzyme concentration. The Michaelis constant (K_m) of the enzyme was 2.1×10^–3M.The investigations are a part of the thesis presented to University of Lucknow, India.Acknowledgments. The authors are grateful to the University Grants Commission, India for the award of a Junior Research Fellowship.     

Zur Kenntnis des Muscarins

Summary The alkaloid muscarin was isolated from fly agaric. The analyses of crystallized salts (chloride, tetra-chloroaurate,Reinecke's salt) led to C₉H₂₀O₂N⁺ as the simplest formula. The presence of aldehyde and tri-methyl-ammonium groups, which had been assumed hitherto, could not be proved. The quaternary nature of the nitrogen atom was shown. Pharmacological tests on frog heart, rabbit gut and cats show the purely peripheral parasympathomimetic effect of the smallest doses.     

Agglutininbildung durch verschiedene Proteinfraktionen vonSalmonella ballerup

Summary The author has examined the agglutinogenic property of nucleoprotein and its components, the nucleic acid and proteins fromS. ballerup. The nucleoprotein was obtained by the extraction of fresh bacteria desintegrated by means of glass powder at pH 8.4 and precipitated with acetic acid at pH 4.6, and its components by splitting the nucleoprotein with 0.5% sodium carbonate at pH 5.5. The protein component was separated from the nucleic acid by forming a chloroform-proteingel. The protein component was submitted to a further purification by dissolving at pH 7 and precipitating at pH 5.5. Rabbits to whom 4–8 mg of the substance were given in 10–12 doses were used for the immunization. The agglutinins were determined byHeidelberger andKabat's quantitative method with aS. ballerup suspension. The maximum quantity of agglutinin is shown in mg nitrogen per 1 cm³ of serum. In comparison with the results obtained by the immunization with whole germs, it follows that, by means of nitrogen compounds, the nucleoprotein has the most substantial agglutinogenic effect, and the nucleic acid the poorest one.     

Experiments on the mechanism of the inhibition of mitochondrial Ca2+ transport by La3+ and ruthenium red

Summary The effects of La³⁺ and ruthenium red on the energy-linked uptake of Ca²⁺ mediated by a synthetic neutral Ca²⁺ ionophore have been investigated in rat liver mitochondria. The results indicate that unspecific surface charge effects do not play a major role in the mechanism of inhibition of mitochondrial Ca²⁺ transport by La³⁺ and ruthenium red.Acknowledgments. The authors are indebted to Prof. W. Simon, ETH Zurich, for having provided samples of the synthetic neutral Ca²⁺ ligand, and to M. Mattenberger for the valuable technical assistence. The work was supported by a grant of the Swiss Nationalfonds (grant No. 3.1720.75).     

Explaining Leibniz equivalence as difference of non-inertial appearances: Dis-solution of the Hole Argument and physical individuation of point-events

“The last remnant of physical objectivity of space–time” is disclosed in the case of a continuous family of spatially non-compact models of general relativity (GR). The physical individuation of point-events is furnished by the autonomous degrees of freedom of the gravitational field (viz., the Dirac observables) which represent—as it were—the ontic part of the metric field. The physical role of the epistemic part (viz. the gauge variables) is likewise clarified as embodying the unavoidable non-inertial aspects of GR. At the end the philosophical import of the Hole Argument is substantially weakened and in fact the Argument itself dissolved, while a specific four-dimensional holistic and structuralist view of space–time (called point-structuralism) emerges, including elements common to the tradition of both substantivalism and relationism. The observables of our models undergo real temporal change: this gives new evidence to the fact that statements like the frozen-time character of evolution, as other ontological claims about GR, are model dependent.     

L'aorte de l'embryon de poulet: histogénèse,cultures organotypiques,stimulations expérimentales

Summary The authors studied the structure of the aortic wall of chick embryos during embryonal development and after hatching up to the age of 1 month. The typical morphology appears on about the seventh day of incubation; it is established on the twelfth day and it does not change afterwards, there is only an increase in the relative quantities of its morphological components. The aorta is of muscular type in its caudal half, while its cranial half is elastic. The cultures of the elastic cranial half and of the muscular caudal half gave the same results already obtained from the explantation in vitro of elastic arteries (anonyma and pulmonary arteries) and of muscular arteries (carotid).

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Ces recherches ont été faites grâce à un subside du Fonds National Suisse de la Recherche scientifique et de la Fondation E. Barell de la Maison Hoffmann-La Roche SA, Bâle.     

The morphology of the lateral line system in 3 species of Pacific cottoid fishes occupying disparate habitats

Summary The superficial neuromasts inLeptocottus armatus (Pacific staghorn sculpin) andOligocottus maculosus (tidepool sculpin) are depressed below the rim of an epidermal collar, whereas the superficial neuromasts inPsychrolutes paradoxus (tadpole sculpin) are surrounded by a pair of hillocks. The lateral line canal system appears identical across these species, whereas the system of superficial neuromasts shows some intraspecific variation. The sand-livingLeptocottus has a more highly developed system of superficial neuromasts thanOligocottus, which lives in a rocky habitat. The present results support the correlation between lateral line system morphology and habitat features previously postulated by Dijkgraaf.     

Classification and distribution ofFicus

Summary The classification of the genusFicus has changed considerably in the course of time and is still the subject of further research and discussion. The main subdivisions in the most recent classification by Corner¹² are presented together with the genera of pollinating fig wasps (Agaonidae) associated with them. These subdivisions are discussed and grouped according to morphological and functional traits, in particular in connection with the unique pollination system. Two main groups are recognized: one with only monoecious species and the other with predominantly (gyno)dioecious species. The former comprises two subgroups (Pharmacosycea andUrostigma) and the latter three, more profoundly different subgroups (Ficus, Sycidium andSycomorus). The neotropical representatives of the genus are discussed in somewhat more detail. In addition, the distribution of the genus is summarized for the three main regions of distribution; Africa, America, and Asia-Australasia. Finally the concordance between subdivisions ofFicus and those of the Agaonidae is briefly discussed.     

Nα-quinaldyl-L-arginine·HCl,a new defensive alkaloid fromSubcoccinella-24-punctata (Coleoptera,Coccinellidae)

The isolation of N-quinaldyl-L-arginine·HCl (1) from the CoccinellidaeSubcoccinella-24-punctata is reported. The structure, first established on the basis of the analysis of the spectral properties of1, has been confirmed by synthesis. The alkaloid is of endogenous origin and markedly deterrent to ants.     

Dauerüberwachung der fetalen Herzaktionen unter der Geburt mittels Ultraschall

Summary The report concerns a new method for continuous observation of foetal heart frequency during delivery. The apparatus uses ultrasonic energy according to the Doppler-effect. The equipment is compact, reliable and relatively inexpensive. The ultrasonic energy used, is far below the intensities required to produce harmful effects in biological structures.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft und der Paul-Martini-Stiftung der Medizinisch-pharmazeutischen Studiengesellschaft e.V. Frankfurt a. M.     

Effects of selective dopamine D1 and D2 antagonists on male rat sexual behavior

Summary The effects of selective dopamine (DA) D₁ and D₂ antagonists on male rat sexual behavior were investigated. The D₁ antagonist (+)SCH-23390, 25–100 g kg^–1 s.c. –20 min, and the D₂ antagonist raclopride, 0.1–1.6 mg kg^–1 s.c., –20 min, decreased both the number of mounts and intromissions preceding ejaculation. No statistically significant effects in the time up to ejaculation or in the time up to the first intromission were noted, whereas both compounds produced a statistically significant increase in the post-ejaculatory interval. The effect can generally be characterized as psychomotor inhibition, and no evidence was obtained for a specific role of DA D₁ or D₂ receptors in the mediation of male rat sexual behavior.The expert technical assistance of Ms Elisabeth Wallin is gratefully acknowledged. The figures were skilfully prepared by Ms Madelene Kröning at the Department of Psychology. This study received support from the Bank of Sweden tercentenary Foundation, The Swedish MRC and Wilhelm and Martina Lundgren Foundation.     

Über die farbgebende Gruppe von Crenilabrus-Blau

Summary The blue chromoproteid isolated from the fins ofCrenilabrus pavo C.V. is split by alkali hydrolysis into a protein and a pigment soluble in chloroform. The pigment is identified as biliverdin by its positive Gmelinreaction, the UV and visible absorption spectrum, and the chromatographic behaviour of its dimethyl ester. The lowest molecular weight of the chromoproteid has been evaluated from its biliverdin content to be 37,000±2400; different chromatographic fractions are presumably oligomeres of this unit.

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Herrn Professor Dr.Richard Kuhn zum 65. Geburtstag gewidmet.     

Polarité électrique de fragments de Carotte cultivésin vitro

Summary The determination of PD's on carrot fragments growingin vitro has shown an electrical polarity of primary and secondary cultures of these tissues. The neoformations are negative in relation to the basis of the fragment. Controls, whether turned upside down or not, exhibit a similar polarity, which is influenced by the medium. The relation between electrical and morphological polarity cannot be stated at present.

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Grâce à un subside du Fonds national pour la Recherche scientifique, j'ai pu m'initier aux techniques récentes de culture de tissus dans le laboratoire deM. Gautheret, à Paris, que je remercie ici, ainsi que le Comité du Fonds (P.E.P.).     

La question des hétérochromosomes chez les Sauropsidés. Oiseaux

Summary The chromosomes of the fowl were studied with the aid ofMakino's andNishimura's water pretreatment squash technique, modified byMatthey, in embryonic spleen and gonads of both sexes. The number of chromosomes was found to be about 78; the numerical variations are to be ascribed to technical difficulties, caused by the extremely small size of the microchromosomes, rather than to an unchromosomelike behaviour of the latter, as was supposed byNewcomer andBrant. As to the exact number of chromosomes, we consider its determination beyond the possibilities of cytology. The 5^th largest pair of the male, represented by a single element in the female, could be identified as the sex chromosome pair, in accordance with the findings ofYamashina. The digamety might be of theZ-O orZ-W type.     

The legs ofMusca domestica andGlossina morsitans females as the site of sex pheromone release

Summary The site of sex pheromone release inMusca domestica andGlossina morsitans is the legs. Unicellular glands restricted to the tarsi and to the tibia are proposed as the source of the pheromone. The structure of the glands is described.Acknowledgments. TheMusca domestica stock, obtained from Dr H. Penner at the Department of Health, Jerusalem, was the insecticide-susceptible strain of the WHO Centre, The Zoological Institute, University of Pavia, Italy. Dr A.M. Jordan of the Tsetse Research Laboratory at Bristol suppliedGlossina morsitans pupae.