Among the nitrogen-fixing bacteria associated with the roots of Leptochloa fusca (L.) Kunth in salt-affected soils in the Punjab region of Pakistan, we found a homogeneous group of eight diazotrophs. Cells are vibrioid to S shaped, are motile by one polar flagellum, and produce granules of poly-P-hydroxybutyrate. They have a respiratory type of metabolism, show microaerophilic growth when fixing nitrogen, grow well on salts of organic acids, and can also use fructose and mannitol. On nitrogen-free semisolid media, they require biotin, utilize mannitol, but not glucose or sucrose, and cannot acidify glucose aerobically or anaerobically. Optimal growth occurs at 0.25 % NaCl and 41OC. Deoxyribonucleic acid (DNA)-ribosomal ribonucleic acid (rRNA) hybridizations show that the organisms belong to the Azospirilhm rRNA branch, where they cluster together with Azospirilhm amazonense. They form a phenotypically and protein electrophoretically homogeneous group of bacteria, clearly distinct from Azospirillum amazonense, Azospirillum lipoferum, and Azospirillum brasilense. As no DNA-DNA binding was found with any of the three Azospirillum species, we propose a fourth Azospirilhm species for this group of isolates. Because of better growth at increased NaCl concentrations, we named the new species Azospirillum halopraeferens, Strain Au 4 (= LMG 7108) is the type strain, which has been deposited at the Deutsche Sammlung von Mikroorganismen, Gottingen, Federal Republic of Germany, as DSM 3675.

No abstract

Federal Republic of Germany2 We detected distinct taxonomic relationships among the true Neisseria species, Kingella kingae, Kingella denitrGcans, Eikenella corrodens, all Simonsiella species, the type strain of Alysiellafiliformis, and members of Centers for Disease Control groups EF-4 and M-5. All these taxa constitute one large separate cluster having high levels of ribosomal ribonucleic acid cistron similarity (thermal denaturation temperature range, 74 to 81°C) in ribosomal ribonucleic acid superfamily 111. There are at least four subbranches. We found high deoxyribonucleic acid (DNA)-DNA homology values between Neisseria gonorrhoeae and some other true Neisseriu species and within the following species: Simonsiella muelleri, Simonsiella crassa, Simonsiella steedue, Kingella denitrificans, and Eikenella corrodens. All of the members of this large cluster have genome base compositions in the range from 42.8 to 57.7 mol% guanine plus cytosine. The molecular complexities of the genomic DNAs are 2.2 X lo9 to 2.7 x lo9 for Sirnonsiella and Alysiella species and 1.4 X lo9 to 1.8 X lo9 for * Corresponding author.