Die Chloroplastendrehung beiMougeotia

Summary By means of partial illumination with small spots of monochromatic light, polarized obliquely to the cell axis, we could demonstrate that the phytochrome molecules inMougeotia are oriented in a spiral pattern around the cell surface. The lines of this spiral form an angle of about 45^o with the cell axis. The degree of exactness of this orientation has been discussed.

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Mit 7 Textabbildungen

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Herrn Professor Dr.E. Heitz zum 70. Geburtstag.     

Isolation and characterization of a <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>-dicyclohexylcarbodiimide-resistant mutant of <Emphasis Type="Italic">Methanothermobacter thermautotrophicus</Emphasis> with alterations to the ATP synthesis machinery

A spontaneous mutant of Methanothermobacter thermautotrophicus resistant toward the ATP-synthase inhibitor N,N′-dicyclohexylcarbodiimide (DCCD) was isolated. DCCD normally inhibits methanogenic electron-transport-driven ATP synthesis, however, the DCCD-resistant strain exhibited methanogenesis in the presence of 300 μmol/L DCCD. Total ATP synthesis was shown to be higher in the mutant strain, both in the presence and absence of DCCD. These results suggested a modification in the ATP-synthesizing system of the mutant strain. Using Blue Native PAGE combined with MALDI TOF/TOF mass spectrometry, increased concentrations of both the A₁ and A_o subcomplexes of the A₁A_o-type synthase were identified in the mutant strain. However, no alterations were found in the structural genes (atp) for the A₁A_o ATP synthase. The results imply that DCCD resistance is a consequence of increased A₁A_o ATP synthase expression, and suggest that genes involved in regulating synthase expression are responsible for DCCD resistance.     

Classification des souches du groupeBacillus thuringiensis par la détermination de l'antigène flagellaire

Summary The serological study of 26 new strains ofBacillus thuringiensis (of which the biochemical features are also given) makes it possible to classify these strains into: 1^o Strains which are in concordance with the six serotypes previously described. 2^o Strains which have a new H antigen. Here, we describe two new serotypes: serotype 7 (aizawai), serotype 8 (morrisoni). On the other hand, the serological study of five new strains ofB. thuringiensis belonging to serotype 4 shows that the H₄ antigen must be divided into ?sub-factors?: ?4 a, 4b? to be found in the strains sotto, dendrolimus, T.84-A, L (Grig) and ?4 a, 4 c? to be found in the strains Pil 94, 1748 and Rhodesia. Table 6 gives the present statute of theB. thuringiensis strains' classification by the flagellar agglutination technic.

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Avec la collaboration technique deM. Lechevallier etT. Le Borgne. Nous remercions vivement les collègues qui ont bien voulu nous adresser des cultures et nous nous tenons à la disposition de tous ceux qui seraient intéresés par la détermination de l'antigène H de leurs souches. Nous remercions également notre collègueLe Minor pour ses précieux conseils.     

Les ichneumonides D'Égypte

Zusammenfassung Diese erste Arbeit über die Ichneumoniden von ?gypten behandelt 101 Arten, die verglichen und kommentiert werden. 9 dieser Arten werden neu beschrieben. Sie schliessen sich an jene an, die in neueren Arbeiten vonJ. F. Aubert aus Nordafrika und dem Nahen Osten beschrieben worden sind. Ausserdem werden in der vorliegenden Arbeit 9 neue Synonymien herausgestellt; für 2 Arten wird eines der Geschlechter zum ersten Male beschrieben. Diese Ichneumoniden, die lebhaft rot und gelb gef?rbt sind, geh?ren zur Wüstenfauna, die im Nahen Osten und vor allem in der Sahara vorkommt. Schliesslich wird, ebenfalls zum ersten Male, eine komplette Bibliographie aller Arbeiten über Ichneumoniden von Nordafrika und dem Nahen Orient zusammengestellt.

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Contribution à l'étude des Hyménoptères n^o 7 (voir n^o 6in Ann. Sc. Nat., 12^e série, 8, 1966, p. 391–493).     

Sensibilité de la pyrale du mais (Ostrinia nubilalis) [Lep.: Pyralidae] aux hyphomycetes entomopathogenes

Résumé Les œufs de la pyrale du ma?s,Ostrinia nubilalis (Hübner), sont très sensibles àMetarhizium anisopliae (Metsch.)/Sorokin etPaecilomyces fumosoroseus (Wize) (Brown-Smith). Toutes conditions égales par ailleurs, les premiers stades larvaires meurent plus vite mais dans une proportion plus faible que les stades plus agés.Beauveria bassiana (Bals.) (Vuillemin) n^o 147 etM. anisopliae n^o 139 sont particulièrement pathogènes pour ce stade tandis queP. fumoso-roseus attaque facilement les chrysalides. Par adjonction d'une dose faible de chlorpyriphos on sensibilise les larves à la mycose. Les chenilles diapausantes sont très sensibles à la mycose puisque même des doses très faibles (40 sp/cm²) tuent plus de 50% de la population.

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Summary The egges of the European corn borer,Ostrinia nubilalis (Hübner) are very susceptible toMetarhizium anisopliae (Metsch.) Sorokin andPaecilomyces fumoso-roseus (Wize) (Brown-Smith). Whereas all the other conditions are equal, the 1 st larval instars die quicker but in a lower proportion than the later.Beauveria bassiana (Bals.) Vuillemin n^o 147 andM. anisopliae n^o 139 are especially pathogenic to this instar whereasP. fumoso-roseus easily attacks the pupae. By adding a low dose of chlorpyriphos the larvae are more susceptible to mycosis. The diapausing caterpillars are very susceptible to mycosis since doses even very low (40 sp/cm² kill more than 50 % of the population.

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Avec la collaboration technique de Mmes J. Goussard & L. Sénéchal.     

Analyse de la structure fine des chromosomes du Gorille (Gorilla gorilla)

Summary Prometaphasic chromosomes of Gorilla, Homo and Pan are compared, using R, Q, T and H-bands techniques in complement of a previous work (Lejeune et al., 1973). Various mechanisms of chromosomal rearrangements are demonstrated with particular reference to heterochromatic segments. Some phylogenic conclusions are proposed.

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Zusammenfassung Prometaphase-Chromosomen von Gorilla, Mensch und Schimpanse werden mit hilfe der R-, Q-, T- und H-Bandentechnik verglichen; frühere Arbeiten (Lejeune et al., 1973) werden dadurch ergänzt. Verschiedene Mechanismen von Chromosomen-Rearrangements werden dargestellt; dabei finden die Heterochromatin-Segmente besondere Beachtung. Einige phylogenetische Folgerungen werden gezogen.

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Travail de l'E.R.A. n^o 47 du C.N.R.S.     

Early evolution of the chromosomal structure of Triticum turgidum–Aegilops ovata amphiploids carrying and lacking the Ph1 gene

After two selfing generations of two different Triticum turgidum –Aegilops ovata amphiploids carrying the Ph1 gene, or lacking it (ph1c mutant), karyotypes of their offspring were scored by GISH (genomic in situ hybridization). On average, the chromosome number was lower than expected (56 chromosomes) on the basis of the parental constitutions (T. turgidum, AABB, 2n=4x=28; Ae. ovata, M^oM^oU^oU^o, 2n=4x=28). The lost chromosomes belonged to the wild Aegilops species. The two families differed greatly by their number of intergenomic translocations, also detected by GISH. The ph1c family showed nine translocations over 12 plants while only one translocation was observed in the Ph1 family. All exchanges involved either the M^o and U^o chromosomes or the M^o and wheat chromosomes, the size of the exchanged segment ranging from 3% to 36% of the total chromosome length. The results suggest an epistatic effect of the ph1c deletion over the genetic diploidizing system that operates in Ae. ovata since translocated chromosomes are most-likely derived from homoeologous recombination. The potential of these results for wheat breeding programmes is also considered. Received: 28 November 2000 / Accepted: 20 March 2001     

Sensibilité des larves deSpodoptera littoralis [Lep.: Noctuidae] aux hyphomycètes entomopathogènesNomuraea rileyi etPaecilomyces fumoso-roseus

Résumé L'étude de la sensibilité des chenilles deSpodoptera littoralis Boisd. à des doses croissantes de spores deNomuraea rileyi (F.)Samson, montre que le 6^e et dernier stade est plus résistant que le 1^er et surtout les 4^e et 5^e stades larvaires. La virulence du pathotypeN. rileyi n^o 5 à l'égard des larves de cette noctuelle est élevée puisque le temps léthal 50 % (TL 50) est de 6 j en moyenne. Pendant l'incubation de la maladie les chenilles continuent de s'alimenter mais l'infection peut réduire jusqu'à 60 % la prise alimentaire par rapport à la consommation des larves des lots témoins. Toutes conditions égales par ailleurs, la mortalité provoquée parN. rileyi n^o 5 après traitement des larves nouvelles-nées est supérieure lorsque les insectes sont maintenus à 25°C par rapport à celle constatée à 20°C. Cependant pour une dose d'inoculum élevée, les conditions thermiques (20°, 25° ou 28°C), ne modifient pas sensiblement la réponse à l'infection parN. rileyi n^o 5 alors qu'elles limitent l'efficacité d'un pathotype moins virulent:Paecilomyces fumoso-roseus Wize no^o 39.

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Summary Laboratory studies were conducted to determine the susceptibility of various larval instars of the cotton leafworm,Spodoptera littoralis Boisd. to different spore doses ofNomuraea rileyi (F.)Samson to investigate the influence of temperature on the infection by this fungus and byPaecilomyces fumosoroseus Wize. Contaminations were obtained by direct spraying on larvae in tower apparatus or by feeding of larvae on treated pieces of leaf during 48 h or 72 h. The influence of cryptogamic infection on food consumption was studied by measuring surfaces of standard cabbage leaf disces submitted to treated and control larvae. Angular values mortality rates were submitted to the 2- or 3-way analysis of variance and comparisons of means were made by theDuncan's test. In some cases we have also considered the time-mortality and the dose-mortality curves. The 6th instar was more resistant than all other tested instars. TL50 were found to be 6 days in most cases. During incubation of the disease, larvae continued to feed, but food consumption could be reduced at 40 % of controls. Larval mortality due toN. rileyi N^o 5, recorded after 8 days of incubation, was higher at 25°C than at 20°C. Nevertheless, at high dosage, efficiency ofN. rileyi N^o 5 was not affected by temperature at 20°, 25° and 28°C. The other pathotype,P. fumoso-roseus N^o 39 was more effective at 20°C than at 25° and 28°. At 32°C, the temperature, unfavourable to fungal growth, limited mortality at non significant rates.

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Avec la collaboration technique deH. Vermeil de Conchard.     

Lactose-H(OH) transport system of Escherichia coli Multistate gated pore model based on half-sites stoichiometry for high-affinity substrate binding in a symmetrical dimer

A model is proposed for the d-galactoside-H⁺(⁻OH) transporter of Escherichia coli that accounts for essentially all the experimental observations established for this system to date. In this model, the functional unit is postulated to be a dimer (consisting of two copies of lacY-specified polypeptide) which spans the membrane with a 2-fold symmetry axis in the membrane plane (Lancaster, J.R. (1978) J. Theor. Biol. 75, 35–50). The functional dimer is assumed to possess a single pore flanked by an inner gate (g_i) and an outer gate (g_o) and encompassing two oppositely oriented galactoside binding sites, designated m and μ. When g_o is open and g_i is closed under non-energized conditions, binding site m adopts a configuration defined as State A (i.e., m_o^A) exhibiting high affinity toward Class G^a galactosides (thiodigalactoside, melibiose, α-p-nitrophenylgalactoside) but low affinity for Class G^b galactosides (lactose, β-o-nitrophenylgalactoside, β-isopropylthiogalactoside), whereas binding site μ adopts State B (i.e., μ_o^B) displaying relatively high affinity toward Class G^b galactosides but comparatively low affinity for Class G^a galactosides; further, each m_o^A : μ_o^B dimer contains one thiol group whose reaction with N-ethylmaleimide inactivates the transporter unless blocked by galactoside binding at site m_o^A, while the second homologous thiol of the dimer is unreactive toward thiol reagents. Translocation of the m_o^A : μ_o^B dimer involves closing of g_o followed by opening of g_i, and causes the two thiols (as well as sites m and μ) to interchange roles in a symmetrical fashion: m_o^A : μ_o^B ↔ m_i^B : μ_i^A. In the presence of a substantial (negative) transmembrane Δμ~_H⁺, the m : μ dimer is postulated to undergo an electrogenic protein conformational change to a second form, ^*(m : μ), in which both sites m and μ possess low affinity toward internal Class G^b substrates; galactoside transport in both m : μ and ^*(m : μ) is assumed to be coupled to H⁺-symport (⁻OH-antiport) with a stoichiometry of approximately 1 : 1. Finally, five characteristic predictions of the half-sites model are outlined for further tests of its validity.     

Structural and energetic basis for H+ versus Na+ binding selectivity in ATP synthase Fo rotors

The functional mechanism of the F₁F_o ATP synthase, like many membrane transporters and pumps, entails a conformational cycle that is coupled to the movement of H⁺ or Na⁺ ions across its transmembrane domain, down an electrochemical gradient. This coupling is an efficient means of energy transduction and regulation, provided that ion binding to the membrane domain, known as F_o, is appropriately selective. In this study we set out to establish the structural and energetic basis for the ion-binding selectivity of the membrane-embedded F_o rotors of two representative ATP synthases. First, we use a biochemical approach to demonstrate the inherent binding selectivity of these rotors, that is, independently from the rest of the enzyme. We then use atomically detailed computer simulations of wild-type and mutagenized rotors to calculate and rationalize their selectivity, on the basis of the structure, dynamics and coordination chemistry of the binding sites. We conclude that H⁺ selectivity is most likely a robust property of all F_o rotors, arising from the prominent presence of a conserved carboxylic acid and its intrinsic chemical propensity for protonation, as well as from the structural plasticity of the binding sites. In H⁺-coupled rotors, the incorporation of hydrophobic side chains to the binding sites enhances this inherent H⁺ selectivity. Size restriction may also favor H⁺ over Na⁺, but increasing size alone does not confer Na⁺ selectivity. Rather, the degree to which F_o rotors may exhibit Na⁺ coupling relies on the presence of a sufficient number of suitable coordinating side chains and/or structural water molecules. These ligands accomplish a shift in the relative binding energetics, which under some physiological conditions may be sufficient to provide Na⁺ dependence.     

Characteristics of Transposon Insertion Mutants of Mandelic Acid-utilizing Pseudomonas putida Strain A10L

A soil isolate, Pseudomonas putida strain A10L that utilizes mandelate via the mandelate pathway was mutagenized by transposon Tn5-Mob insertion and a mutant 168 lacking mandelate racemase (MR) and a mutant 254 lacking benzoylformate decarboxylase (BFDC) were obtained. Expression of (S)-mandelate dehydrogenase (MDH), BFDC, NAD⁺ -dependent benzaldehyde dehydrogenase (BDH) and NADP⁺ -dependent BDH in the MR-lacking mutant was not affected by the insertion, and it was inducible similarly to the wild type strain. On the other hand, expression of MR and MDH in the BFDC-lacking mutant was low and constitutive, and NAD⁺ - and NADP⁺ -dependent BDHs were produced at a rather high level under non-induced conditions by the mutant. Genes for MR (mdlA), MDH (mdlB), and BFDC (mdlC) were indicated to be organized in an operon in the order of mdlCBA. Optical resolution to obtain (R)-mandelate, a useful synthon for pharmaceuticals, was shown to be performed with the MR-lacking mutant.     

Localization of a non-Mendelian gene in Chlamydomonas reinhardii

Summary Transfer of a non-Mendelian neamine-dependent (nd) mutant to an antibioticfree medium results in neamine-sensitive and neamine-resistent revertants. These reversions are caused by extranuclear mutations.The neamine-sensitive revertants are no more able to split offnd-cells after back-donation to neamine containing medium. Therefore they are different from the streptomycin-sensitive revertants of a streptomycin-dependent (sd) mutant. These mutants were capable ofsd-segregation though their potence ofsd-segregation diminished on antibiotic-free medium with increasing time of cultivation.The different behaviour can be explained by the fact that manysd-genes are present which have to be appointed to the mitochondria. On the other side, thend-gene exists only in few copies and is located therefore in the chloroplast.Several experiments with differing methods are discussed to localize the extranuclear genes.

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Vorgelegt durch G. Melchers     

Genetics of the apolipoprotein E-system in man

The polymorphism of apolipoprotein E (Apo E) in man is controlled by two codominant alleles, Apo Eⁿ and Apo E^d, at the Apo E-N/D locus and by two alleles, the dominant, Apo E4⁺, and the recessive, Apo E4^o, at the Apo E4 locus.

Frequency distribution analysis of Apo E phenotypes demonstrated a highly significant association between both systems (P ~ 1%). The Apo E4-(+) variant was about twice as frequent in phenotype Apo E-N (30.1%) than in phenotype Apo E-ND (16.4%). The phenotypic combination Apo E-D/-E4(+) was not observed. The segregation of Apo E phenotypes in informative matings is consistent with a close linkage of both loci.

The results may be explained by different models. On the basis of the present data, these models cannot be distinguished by formal genetic criteria. (1) Haplotypes Apo Eⁿ/E4⁺, Apo Eⁿ/E4^o, and Apo E^d/E4^o determine the different phenotypes, and a linkage disequilibrium exists of Δ = .0147 between the E-N/D and E4 loci. (2) The fourth haplotype, Apo E^d/E4⁺, exists, but the gene E4⁺ is not expressed in coupling with Apo E^d. The four-haplotype model seems more attractive in view of Apo E-N/D polymorphism's quantitative character and of biochemical results, which show that phenotypes Apo E-N and Apo E-D differ in the apparent molecular weight (M_r) of the respective major Apo E polymorphic form. Hence, the Apo E-N/D locus may control structural genes involved in the posttranslational modification of Apo E. (3) Finally, there may exist only one Apo E structural gene locus but with mutations at two sites susceptible to posttranslational modification.

     

RAG3 gene and transcriptional regulation of the pyruvate decarboxylase gene in Kluyveromyces lactis

The RAG3 gene has been cloned from a Kluyveromyces lactis genomic library by complementation of the rag3 mutation, which shows impaired fermentative growth on glucose in the presence of respiratory inhibitors. From the nucleotide sequence of the cloned DNA, which contained an open reading frame of 765 codons, the predicted protein is 49.5% identical to the Pdc2 protein of Saccharomyces cerevisiae, a regulator of pyruvate decarboxylase in this yeast. Measurement of the pyruvate decarboxylase activity in the original rag3–1 mutant and in the null mutant confirmed that the RAG3 gene is involved in pyruvate decarboxylase synthesis in K. lactis. The effect is exerted at the mRNA level of the pyruvate decarboxylase structural gene KIPDCA. Despite analogies between the RAG3 gene of K. lactis and the PDC2 gene of S. cerevisiae, these genes were unable to reciprocally complement.     

Physiological function of soluble cytochrome <Emphasis Type="Italic">c</Emphasis>-552 from alkaliphilic <Emphasis Type="Italic">Pseudomonas alcaliphila</Emphasis> AL15-21<Superscript>T</Superscript>

It has been found that the alkaliphilic Gram-negative bacterium Pseudomonas alcaliphila AL15-21^T produces a larger amount of soluble c-type cytochromes at pH 10.0 under air-limited condition than at pH 7.0 under high aeration. Cytochrome c-552 was confirmed as the major c-type cytochrome among three soluble c-type cytochromes in the strain. To understand the physiological function of cytochrome c-552, a P. alcaliphila AL15-21^T cytochrome c-552 gene deletion mutant without a marker gene was constructed by electrotransformation adjusted in this study for the strain. The maximum specific growth rate and maximum cell turbidity of cells grown at pHs 7.0 and 10.0 under the high-aeration condition did not differ significantly between the wild-type and cytochrome c-552 deletion mutant strains. In the mutant grown at pH 10.0 under low-aeration condition, marked decreases in the maximum specific growth rate (40%) and maximum cell turbidity (25%) compared with the wild type were observed. On the other hand, the oxygen consumption rates of cell suspensions of the mutant obtained by the growth at pH 10 under low-aeration condition were slightly higher than that of the wild type. Considering the high electron-retaining ability of cytochrome c-552, the above observations could be accounted for by cytochrome c-552 acting as an electron sink in the periplasmic space. This may facilitate terminal oxidation in the respiratory system at high pH under air-limited conditions.     

Analysis of sorbose resistance in Neurospora crassa double mutants; contribution to the genetics of active transport. II

Summary 4 sorbose-resistant Neurospora crassa mutants, whose resistance was found to be due to a decreased rate of sorbose uptake, were crossed in two pairs with each other. In both crosses mutants were combined which contained mutational changes at sites not closely linked with each other, and therefore representing separate genes. Among the ascosporeisolates, double mutant recombinants were selected. This was facilitated by suitable markers in one of the crosses.Growth of these double mutants with and without added sorbose was compaired with that of a number of parental- and wildtype-reisolates from the same crosses. In spite of the fact that the double mutant sor ^r A-10/sor ^r C-17 without sorbose grows more slowly than the parental- and wildtype-reisolates, it proved much more resistant than these in the presence of sorbose. The same was true for the second double mutant sor ^r A-2/sor ^r -6.Since it can be shown that probably none of the two A-mutants used (sor ^r A-10 and sor ^r A-2) forms any active A-protein, it seems unlikely that the respective pairs of genes in the wildtype specify proteins catalyzing a reaction sequence. Another possibility envisages a compound-permease made up of subunits specified by the respective genes, but is not very likely either. A third possibility, which explains satisfactorily all earlier as well as the present results, is that the resp. genes code for identical or different proteins which as isopermeases catalyze one and the same reaction step in the course of the uptake of sorbose.

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III. Teil einer Habilitationsschrift bei der Naturwissenschaftlichen Fakultät der Universität München.