Eiweissvermehrung in ein- und zweikernigen systemen vonAcetabularia

Summary (1) The rate of protein synthesis was found to be different inAcetabularia crenulata andAcetabularia mediterranea the higher cytoplasmic protein synthesis inA. crenulata depending upon the diameter of the stalk.(2) In systems containing one or two nuclei, there was no difference in the rate of cytoplasmic synthesis of proteins. This corresponds to the diminution of size and efficiency of the nuclei in binucleated systems.(3) In interspecific grafts, the rate of cytoplasmic protein synthesis corresponds nearly to the rate of protein synthesis ofAcetabularia crenulata. Corresponding to morphogenetic processes, thecren-action is prevalent.     

Mikrobiologische Spaltung razemischer Steroide. Synthese vond-Aldosteron

Summary A racemic intermediate in the total synthesis ofd, l-aldosterone, thed, l-20-oxo-pregnene derivative I, was converted by incubation with a mold hydroxylating in the 21-position into thed-20-oxo-21-hydroxy-pregnene derivative II, whereas thel-antipode of the starting material remained unchanged. This stereospecific microbiological reaction, comprising a separation of racemic modifications, represents the last remaining step in the synthesis of naturald-aldosterone.Other microbiological conversions of racemic steroids, dehydrogenation and hydrogenation, were also shown to proceed only with thed-enantiomer, leaving thel-form of thed, l-substrate intact.The advantages of this new microbiological method for the resolution of racemic modifications during the total synthesis of steroids are discussed.     

Is ATP synthesized by a vacuolar-ATPase in the extremely halophilic bacteria?

The proton-dependent synthesis of ATP was demonstrated in representative members of the generaHalobacterium, Haloarcula, andHaloferax. In all cases, synthesis was not inhibited by nitrate or N-ethylmaleimide, inhibitors of the vacuolar-like ATPase found in Archaea, but was affected by azide, an inhibitor of F₀F₁-ATP syntheses. These observations extend the earlier observations withHalobacterium saccharovorum and suggest that ATP synthesis in these organisms is brought about by an F₀F₁-APT synthase.     

Immunocytochemical reaction of a haemocyanin antibody in the midgut gland ofNautilus (Cephalopoda,Tetrabranchiata)

The branchial gland of the dibranchiate cephalopods is described as the site of haemocyanin synthesis. Because there is no equivalent to this organ in tetrabranchiate cephalopods the localization of haemocyanin synthesis remained unknown for a long time. In this study we could confirm the conclusions from prelimnary investigations concerning the copper content of the midgut gland ofNautilus, which gave the first indications for a possible localization of haemocyanin synthesis in this organ. We developed a polyclonal antibody againstNautilus haemocyanin, tested its specificity, and used it on ultra-thin sections of the tissue of the midgut gland. It could be shown that there is a clear imunogold precipitation only on the triangular basal cells in the terminal alveoli. All the other types of cell in this organ were free of any immunoreactivity. It can be supposed that the triangular basal cells in the terminal alveoli of the midgut gland are the sites of haemocyanin synthesis inNautilus.     

Sporulation and δ-endotoxin synthesis by Bacillus thuringiensis

Bacillus thuringiensis is distinguished from the very closely related Bacillus cereus and Bacillus anthracis by the presence of several plasmid-encoded δ-endotoxin genes. These δ-endotoxins, synthesized as protoxins, are produced in large quantities during sporulation and are packaged into intracellular inclusions. Ingestion of the inclusions by insect larvae leads to protoxin solubilization and conversion to toxins each specific for one of several orders of insects. The toxins form cation-selective channels in the membrane of cells lining the larval midgut with subsequent lethality. In most cases, δ-endotoxin synthesis and sporulation are closely coupled. The latter process in B. thuringiensis is probably virtually identical to that in Bacillus subtilis with the additional use of mother cell sporulation forms of RNA polymerase for the synthesis of the δ-endotoxins. There are other more subtle plasmid-encoded functions or plasmid interactions related to regulating protoxin synthesis. Consideration of both plasmid and chromosomal genes is thus critical for defining this organism.     

Synthesis and metabolism of vertebrate-type steroids by tissues of insects: A critical evaluation

Summary This review covers the synthesis and the metabolism of vertebrate-type steroids (progesterone, testosterone, estradiol, corticosteroids) by insect tissues and discusses the significance of the reactions for insect physiology. Biosynthesis of vertebrate-type steroids from cholesterol hitherto has been demonstrated in only two insect species, i.e. the water beetleAcilius sulcatus (Coleoptera) and the tobacco hornwormManduca sexta (Lepidoptera). InAcilius, steroid synthesis is associated with exosecretion (chemical defense). Nothing, however, is known about a physiological role of the C₂₁ steroid conjugate present in ovaries and eggs ofManduca. No synthesis of vertebrate-type steroids was observed in any other insect investigated to date. Most metabolic conversions of steroids by insects concerned oxidoreduction of oxygen groups (hydroxysteroid dehydrogenase activity) and (polar and apolar) conjugate formation. All important enzymatic steps involved in synthesis and catabolism, as known from studies with tissues of vertebrates, were not, or hardly observed. The conclusion is drawn that typical vertebrate-type (C₂₁, C₁₉ and C₁₈) steroids probably do not act as physiologically active substances in insects.     

Heat shock proteins in three relatedDrosophila species belonging to theobscura group

The effect of heat shock on protein synthesis in three relatedDrosophila species belonging to theobscura group was analyzed on SDS-acrylamide gels. Four major heat shock proteins (hsps) were found in these species, in which synthesis reaches a maximum at 34°C. Although the higher molecular weight proteins are conserved, differences in size were found for the small hsps in these species. By means of in situ hybridization usingD. melanogaster probes for the small hsp genes, it was inferred that the small hsp genes of theobscura group species are clustered at the 27A locus in all three species.     

Modulation of antibody synthesis by an anti-tumour alga

Summary An unicellular alga,Chlorella pyrenoidosa, which had been reported to protect C₃H mice against sarcoma BP8, is shown, when injected in Freund's incomplete adjuvant, to modulate the antibody synthesis induced by immunization with a hapten-carrier complex.C. pyrenoidosa appeared to be able to initiate an antigenic competition between hapten and carrier determinants of the antigen molecule during antibody synthesis, and thus it could be speculated thatC. pyrenoidosa modulates the immune response at the macrophage level.Acknowledgments. This work was supported by the Secrétariat d'Etat aux Universités and by the DGRST, grant No. 77.71347.     

Végétalisation de l'œuf de l'oursinParacentrotus lividus par l'hydrazide de l'acide isonicotinique (isoniazide)

Summary Isonicotinic acid hydrazide (isoniazid) causes vegetalization of whole larvae of the sea urchinParacentrotus lividus. The effects of isoniazid are compared with those of chloramphenicol and lithium ions. The protein synthesis during the phase of reversible determination, i.e. to the late blastula stage, appears to be of paramount importance in the differentiation of larvae. It is suggested that the protein synthesis connected with the determination of ectodermal structures is more sensitive to the action of vegetalizing agents than the protein synthesis connected with the determination of entomesodermal structures.     

Interphase differential sensitivity to protein synthesis inhibition

Summary The effect of protein synthesis inhibition during interphase ofAllium cepa L. root meristem cells was studied. Anisomycin and cycloheximide were used in intermittent treatments during interphase of a synchronous cell subpopulation labelled as binucleate by caffeine, and the delays in reaching prophase were recorded. High sensitivity to protein synthesis inhibition was detected in G₁ and in the S/G₂ boundary, while protein synthesis in most of the S and G₂ phase was not required for the normal timing of next prophase.     

Occurrence of ricinoleic acid in submerged cultures of variousClaviceps sp.

Summary Ricinoleic acid was found in differentClaviceps sp., indicating that it is neither specific chemotaxonomic marker ofClaviceps purpurea, nor a specific indicator of peptide alkaloid synthesis.     

Synthese dercis-erythro- undcis-threo-Formen des Sphingosins

Summary The synthesis ofcis-erythro- andcis-threo-1, 3-dihydroxy-2-amino-4-octadecene, two further stereoisomers of sphingosine, is described.     

Protein synthesis during germination of heterothallic yeast ascospores

Protein synthesis during ascospore germination of the heterothallicSaccharomyces cerevisiae strain AP-3 was investigated. Protein synthesis in the germinating ascospores appeared to begin approximately 20 min following glucose initiation. Since RNA synthesis did not start until approximately 70 min after the onset of germination, strain AP-3 ascospores must contain RNA which is ready for immediate translation. Both trehalase and glyceraldehyde-3-phosphate dehydrogenase activities were found to be affected by the onset of germination. Trehalase activity was found to increase severalfold following 60 min of spore germination but remained relatively constant over the subsequent 120 min examined. Dehydrogenase activity was not detectable in AP-3 ascospores but was measurable in germinating ascospores.     

Lokalisation zusätzlicher RNS-Synthese in Trypsin-behandelten Riesenchromosomen vonChironomus thummi

Summary After injection of buffered trypsin into nuclei of salivary gland cells ofChironomus thummi, the existing puffs in the giant chromosomes are enlarged. Autoradiography shows an increase in RNA synthesis of approximately 3-fold in these puffs. It is argued that histones in puffed chromosome segments are in a structural state that renders them unable to prevent RNA synthesis and at the same time causes them to be attacked earlier by trypsin.     

Interaction ofRhizobium loti strain and host on the biosynthesis of unusual amino acids in leguminous plants

Summary The effect of differentRhizobium loti strains on the biosynthesis of 2,3-diamino-butanoic acid and 2,4-diamino-3-methyl-butanoic acid in root nodules ofLotus tenuis, Anthyllis vulneraria andLupinus densiflorus has been investigated. Results suggest that biosynthesis isRhizobium strain dependent, that the bacteroid is the site of synthesis of the compounds and that their biosynthesis is confined to the symbiosis.     

Effect of inhibitors of protein synthesis from plants on tobacco mosaic virus infection

Summary Ricin, abrin, modeccin, gelonin andMomordica charantia inhibitor, as well as crude extracts ofBryonia dioica seeds and ofDianthus caryophyllus leaves, each inhibit protein synthesis in a rabbit reticulocyte lysate and reduce local lesion production by tobacco mosaic virus, thus resembling the effects of the pokeweed antiviral peptide.     

Dithyreanitrile: an unusual insect antifeedant fromDithyrea wislizenii

Summary Dithyreanitrile, a novel sulfur-containing indole alkaloid, was isolated from the seeds ofDithyrea wislizenii (Cruciferae). Dithyreanitrile inhibits feeding of fall armyworm (Spodoptera frugiperda) and European corn borer (Ostrinia nubilalis) larvae. Dithyreanitrile, the first natural product with two sulfur atoms and a nitrile attached to the same carbon, was characterized by X-ray diffraction, spectroscopy, and chemical synthesis.     

Polyamines as activators of AMP nucleosidase fromAzotobacter vinelandii

Summary Polyamines at physiological concentrations activate AMP nucleosidase fromAzotobacter vinelandii. Biological significance of the activation is discussed in relation to the control of adenylate energy charge and the purine nucleotide synthesis in prokaryotes.     

Analyse électrophorétique des protéines caroténogènes deNeurospora crassa

Summary In an effort to determine the number of proteins responsible for the synthesis of the neutral carotenoids inN. crassa, the soluble protein extracts from light-induced and dark-grown cultures of a neurosporaxanthinless strain were compared electrophoretically. The differences relevant to the carotenogenic proteins were identified by reference to an albino polarity mutant. A single, electrophoretically determinable, protein was found to be specific to carotenogenesis. This implication of a single (presumably an enzyme aggregate) protein controlling carotenoid synthesis is discussed and correlated to the existing genetic, complementation and biochemical evidence.     

Deficiency in renomedullary prostaglandin synthesis related to the evolution of essential hypertension

Summary Continued PG synthesis in the early stages of essential hypertension might reflect an activation of the renal antihypertensive function in respect to neurogenic and/or hormonal pression stimuli, subsequently a deficiency of renal PG synthesis related to irreversible changes with the kidney would lead to the prepoderance of a pressure mechanism, resulting to a further increase of blood pressure.We thank Dr.J. R. Pike of the Upjohn Company, Kalamazoo Michigan, who kindly provided PGs. This work was supported by a grant from INSERM (ATP 17 No. of contract73547917) to Dr.Papanicolaou.