1. Evidence that the barrier to the penetration of oxygen into heterocysts depends upon two layers of the cell envelope

   • Marcia A. Murry
   • C. Peter Wolk

   Original Papers Pages: 469 - 474

2. Regulation of nitrate and nitrite reductases in dinitrogen-fixing cyanobacteria and Nif⁻ mutants

   • José Martín-Nieto
   • Antonia Herrero
   • Enrique Flores

   Original Papers Pages: 475 - 478

3. Thiobacillus prosperus sp. nov., represents a new group of halotolerant metal-mobilizing bacteria isolated from a marine geothermal field

   • Harald Huber
   • Karl O. Stetter

   Original Papers Pages: 479 - 485

4. Identification of aggregation substances of Enterococcus faecalis cells after induction by sex pheromones

   • Dominique Galli
   • Reinhard Wirth
   • Gerhard Wanner

   Original Papers Pages: 486 - 490

5. Localization of aggregation substances of Enterococcus faecalis after induction by sex pheromones

   • Gerhard Wanner
   • Helmut Formanek
   • Reinhard Wirth

   Original Papers Pages: 491 - 497

6. Fermentative degradation of putrescine by new strictly anaerobic bacteria

   • Carola Matthies
   • Frank Mayer
   • Bernhard Schink

   Original Papers Pages: 498 - 505

7. Thermotoga thermarum sp. nov. and Thermotoga neapolitana occurring in African continental solfataric springs

   • Elke Windberger
   • Robert Huber
   • Karl O. Stetter

   Original Papers Pages: 506 - 512

8. Distribution of δ-aminolevulinic acid biosynthetic pathways among phototrophic bacterial groups

   • Yael J. Avissar
   • John G. Ormerod
   • Samuel I. Beale

   Original Papers Pages: 513 - 519

9. Degradation of mandelate and 4-hydroxymandelate by Rhizobium leguminosarum biovar trifolii TA1

   • Y. P. Chen
   • M. J. Dilworth
   • A. R. Glenn

   Original Papers Pages: 520 - 523

10. Ectothiorhodospira marismortui sp. nov., an obligately anaerobic, moderately halophilic purple sulfur bacterium from a hypersaline sulfur spring on the shore of the Dead Sea

    • Aharon Oren
    • Martin Kessel
    • Erko Stackebrandt

    Original Papers Pages: 524 - 529

11. ATP is required for K⁺ active transport in the archaebacterium Haloferax volcanii

    • Jean Meury
    • Masamichi Kohiyama

    Original Papers Pages: 530 - 536

12. Regulation of branched-chain amino acid biosynthesis in Streptomyces fradiae, a producer of tylosin

    • Aleš Vančura
    • Ivana Vančurová
    • Vladimir Křišťan

    Original Papers Pages: 537 - 540

13. Degradation of hydroquinone, gentisate, and benzoate by a fermenting bacterium in pure or defined mixed culture

    • Ulrich Szewzyk
    • Bernhard Schink

    Original Papers Pages: 541 - 545

14. The formation of an oxygen-binding flavohemoprotein in Alcaligenes eutrophus is plasmid-determined

    • Vera Weihs
    • Karin Schmidt
    • Bärbel Friedrich

    Original Papers Pages: 546 - 550

15. Conjugal transfer and expression of streptococcal transposons in Clostridium acetobutylicum

    • Joachim Bertram
    • Peter Dürre

    Original Papers Pages: 551 - 557

16. Simultaneous heterolactic and acetate fermentation in the marine cyanobacterium Oscillatoria limosa incubated anaerobically in the dark

    • Heike Heyer
    • Lucas Stal
    • Wolfgang E. Krumbein

    Original Papers Pages: 558 - 564