1. Effect of nitrogen starvation on ammonium-inhibition of nitrogenase activity in Azotobacter chroococcum

   • Francisco J. Cejudo
   • Antonio Paneque

   Original Papers Pages: 481 - 484

2. Localized insertion of new S-layer during growth of Bacillus stearothermophilus strains

   • Karin Gruber
   • Uwe B. Sleytr

   Original Papers Pages: 485 - 491

3. Defects in cytochrome cd ₁-dependent nitrite respiration of transposon Tn5-induced mutants from Pseudomonas stutzeri

   • W. G. Zumft
   • K. Döhler
   • K. Frunzke

   Original Papers Pages: 492 - 498

4. Rhizobial purine and pyrimidine auxotrophs: nutrient supplementation, genetic analysis, and the symbiotic requirement for the novo purine biosynthesis

   • K. Date Noel
   • Ronald J. Diebold
   • Benita A. Brink

   Original Papers Pages: 499 - 506

5. Arachidonic and oleic acids stimulate zygote formation in the presence of mating pheromone in the yeast, Saccharomyces cerevisiae

   • Syuichi Doi
   • Masayasu Watanabe
   • Masao Yoshimura

   Original Papers Pages: 507 - 508

6. Dependency of growth yield, maintenance and K _s-values on the dissolved oxygen concentration in continuous cultures of Azotobacter vinelandii

   • J. Kuhla
   • J. Oelze

   Original Papers Pages: 509 - 514

7. Base composition of DNA from symbiotic dinoflagellates: a tool for phylogenetic classification

   • Rudolf J. Blank
   • Volker A. R. Huss
   • Walter Kersten

   Original Papers Pages: 515 - 520

8. Differences in lipid composition between free-living and initially adhered cells of a Gram-negative bacterium

   • Anders Valeur
   • Anders Tunlid
   • Göran Odham

   Original Papers Pages: 521 - 526

9. Surface properties from the S-layer of Clostridium thermosaccharolyticum D120-70 and Clostridium thermohydrosulfuricum L111-69

   • Margit Sára
   • Inge Kalsner
   • Uwe B. Sleytr

   Original Papers Pages: 527 - 533

10. Regulation of gluconate and ketogluconate production in Gluconobacter oxydans ATCC 621-H

    • P. R. Levering
    • G. Weenk
    • W. Harder

    Original Papers Pages: 534 - 539

11. Plasmids in carboxydotrophic bacteria: physical and restriction analysis

    • Maria Kraut
    • Ortwin Meyer

    Original Papers Pages: 540 - 546

12. A phylogenetic survey of budding, and/or prosthecate, non-phototrophic eubacteria: membership of Hyphomicrobium, Hyphomonas, Pedomicrobium, Filomicrobium, Caulobacter and “Dichotomicrobium” to the alpha-subdivision of purple non-sulfur bacteria

    • Erko Stackebrandt
    • Angelika Fischer
    • Jan Smida

    Original Papers Pages: 547 - 556

13. Isolation and characterization of mutants of mesophilic methanogenic bacteria resistant to analogues of DNA bases and nucleosides

    • Margaret R. Knox
    • Jane E. Harris

    Original Papers Pages: 557 - 560

14. Isolation of auxotrophs and analysis of regulation of tryptophan biosynthesis in Zymomonas mobilis

    • Christina K. Eddy
    • K. Dale Noel
    • Oliver H. Smith

    Original Papers Pages: 561 - 564

15. Calcium control of differentiation in Phytophthora palmivora

    • Julia M. Griffith
    • Joanne R. Iser
    • Bruce R. Grant

    Original Papers Pages: 565 - 571

16. Isolation of the sulphur reductase and reconstitution of the sulphur respiration of Wolinella succinogenes

    • I. Schröder
    • A. Kröger
    • J. M. Macy

    Original Papers Pages: 572 - 579

17. Fatty acid analysis of four Azospirillum species reveals three groups

    • Sigrid U. Schenk
    • Dietrich Werner

    Short Communication Pages: 580 - 582