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The possibility of the absence of cellular triamines in the four flavobacteria, Flammeovirga aprica IAM 14298, 'Flexibacter aurantiacus subsp. Copepodarum' IFO 15978, 'Microscilla arenaria' IFO 15982 and Saprospira grandis NCIMB 1363, phylogenetically loc

A marine bacterium, Saprospira sp. SS98-5, which was isolated from Kagoshima Bay, Japan, was able to kill and lyse the cells of the diatom Chaetoceros ceratosporum. The multicellular filamentous cells of this bacterium captured the diatom cells, formed cell aggregates, and lysed them in an enriched sea water (ESS) liquid medium. Strain SS98-5 also formed plaques on double layer agar plates incorporating diatom cells. The diatom cell walls were partially degraded at the contact sites with the bacteria, the bacteria invaded from there into the diatom cells, and then the diatom cells were completely lysed. The strain possessed gliding motility and grew as spreading colonies on ESS agar plates containing lower concentrations of polypeptone (below 0.1%) while forming nonspreading colonies on ESS agar plates containing 0.5% polypeptone. Electron micrographs of ultrathin sections demonstrated that microtubule-like structures were observable only in gliding motile cells. Both the gliding motility and the microtubule-like structures were diminished by the addition of podophyllotoxin, an inhibitor of microtubule assembly, suggesting that the microtubule-like structures observed in these bacterial cells are related to their gliding motility.Key words: Saprospira sp., Chaetoceros ceratosporum, gliding motility, algicidal activity, microtubule-like structure.

The cytoplasmic fibril structures of Saprospira sp. strain SS98-5 grown on a low-nutrient agar medium were purified from cell lysates treated with Triton X-100 and were observed by electron microscopy to be about 7 nm in width and 200–300 nm in length. SDS–PAGE of the fibril structures exhibited a single protein band with a molecular mass of 61 kDa. A Saprospira cytoplasmic fibril protein (SCFP), which is a subunit of the fibril structures, was digested with trypsin to oligopeptides and analyzed for amino acid sequences. A partial nucleotide sequence of the SCFP gene was determined after PCR using primers designated from the amino acid sequences of the oligopeptides. SCFP gene including DNA fragments were detected by Southern hybridization using the PCR product for an SCFP gene as a probe and were cloned to determine whole nucleotide sequences. The SCFP gene indicated relatively higher similarity to conserved hypothetical phage tail sheath proteins. A Western immunoblotting analysis showed that SCFP was significantly expressed in gliding cells as compared with nongliding cells. The above findings with the previously reported results suggest that the cytoplasmic fibril structures are possibly related to the gliding motility of Saprospira sp. strain SS98-5.Key words: Saprospira, gliding motility, Saprospira cytoplasmic fibril protein (SCFP).

Gram-negative gliding bacteria that form helical, multicellular filaments are grouped in the genus Saprospira (Fig. 1). All known species live in aquatic environments. They are moderately common but relatively difficult to isolate, and therefore have not been studied very well, although some of them can be cultivated without problems. Relatively little has been added to our knowledge of Saprospira since the first edition of The Prokaryotes (Reichenbach and Dworkin, 1981).

SUMMARY The cyanobacterium Microcystis aeruginosa is the dominant autotroph in hypertrophic Hartbeespoort Dam, South Africa. Tn early summer (November) of 1983 and 1984 Microcystis colonies were heavily colonized by a gram-negative, spiral-shaped organism whose filaments appeared as si.ngle cells under both the light and scanning electron microscope. DNA staining with 4'6 diamidino-2-phenylindole (DAPI) revealed that each filament consisted of a number of bow-shaped cells. The organism has been tentatively identified as a bacterium, Saprospira albida, on the basis of it morphology. The Microcystis cells at the site of colonization were apochlorotic suggesting lysis by Saprospira.

Des rhapidosomes, qui ressemblent assez aux virions de la mosai'que du tabac, se trouvent dans les autolysats de certaines flexibact6ries. En coupes ~ninces de Saprospira grandis, ils apparaissent dans I'endroit du noyau quand les culturcs ont dCpass6 la phase de croissance euponentielle. Apri.s la premi6re apparition des rhapidosomes, les contenus cellulaires dCgCn6rent pendant six heures ( 2 30"); puis ils se d6sintGgrent en lib6rant des centaines de ces particules. On illustre ces phases par une sCrie d'electron micrographes.

Sommaire Plusieurs non-photosynthPtiques microorganismes en filaments spiralCs, qui se deplacent en glissant, sont associCs avec des algues et de la vase. 11s ont CtC group& dans le genre Saprospira des ACxibacteries. La structure et les caract6res physiologiques de sept de telles souches provenant de l'eau douce, cultivCes Q 1'Ctat pur, nous permettent dlCtablir S . tlzermalis nov. sp., S . $ammzlla nov. sp., et S. albida nov. comb. Introduction

SUMMARY: About 90 strains of gliding microbes (flexibacteria) have been considered. Data obtained by Lewin & Lounsbery (1969) and Mandel & Lewin (1969) have been used by Fager (1969) in a computer programme designed to indicate affinities and thereby possible relationships. Largely on the basis of Fager's analysis, a classification of these organisms is here proposed. Including a few species described elsewhere, 27 species and varieties are distinguished, most of them apparently new. A simplified diagnostic key is presented for their identification. They are assigned to six genera, three (Saprospira, Flexithrix and Herpetosiphon) are recognized primarily on morphological grounds; three others (Cytophaga, Flexibacter and Microscilla), here somewhat re-defined, are based largely on other convenient characteristics.

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In our discussion of the gliding bacteria (this Handbook, Chapter 19), we have proposed an alternative classification to that in Bergey’s Manual of Determinative Bacteriology, eighth edition. In accordance with those ideas, this chapter will deal exclusively with unicellular gliding bacteria. All of them are Gram-negative, rod-shaped, slender cells that are often rather delicate; in some cases the cells are very short, but more often they are quite long (Fig. 1). Many organisms of this group exhibit change in cell shape, which either leads to spherical resting cells (microcysts) or results at least in highly pleomorphic populations. In contrast to myxobacteria, no complex morphological structures such as fruiting bodies are produced. As we define them, the Cytophagales include at present the following genera: Cytophaga, Flexibacter, Sporocytophaga, Sphaero-cytophagalCapnocytophaga, Microscilla, and Lysobacter (see Table 1; Fig. 1). The group is, however more heterogenous than may seem from this classification, and will certainly require the establishment of additional genera in the future.

Sommaire De nornbreuses particules en baguette (rhapidosonzes) se trouvent dans tous les cinq cultures lysees de Sap~ospira grandis examinCes. Le microscope Clectronique peut faire distinguer deux formes. Les particules les plus coln~nunes sont des cylindres creux qui ~nesurent 225 X33 mp. Moins nombreux ( < 10yo) sont les cylindres, cle m6rnes dimensions, ~ n a i s pleins, pourvus B une extrCrnit6 d'une queue de 15 mp de large et jusqu'i 300 mp de long. L'isolation des rhapidoso~nes a 6tC rnise h point. Le coefficient de sCditnentation est 250 S. Dcs Cchantillons de rhapidosomes contiennent de la matiPre protCinique e t de l'acide ribonuclCique dans le rapport 2 : 1. La partie prot6iniq~re ne contient pas de methionhe. La partie ribonuclCique ne se sCpare que partielle~nent par agitation en presence du phCnol. Elle ne s'hydrolyse ni dans les solutions alcalines, ni sous I'action de la ribonuciCase pancrCatique; nCanmoins on peut l'hydrolyser avec la phosphodiestCrase du venin de Crotalz~s ada~izantezrs. Ces caractPres peuvent s'expliqucr en postulant que 50-85% de son pentose soit substitue h la position C-2. XprPs les analyses preliminaires (hydrolyse dans l'acide e t separation dans la colonne chromatographique) on est arrive h une composition de bases dans ce rapport molCculaire: adenine, 26.3: guanine, 29.4: cytosine, 24.0: uracil, 20.3. Bien qu'il esiste une ressemblance avec le virus de la ruosalque du tabac, il n'est pas tout h fait exact de considerer les rhapidosornes cornme particules d ' ~ i n virus, car leur pouvoir pathogCnCtiq~ie n'est pas encore mis en evidence.

Most of the 28 species (91 strains) of flexibacteria tested without additives survived after freezing in liquid nitrogen (−196 °C): they included all six Microscilla spp., all three Cytophaga spp., both of the Herpetosiphon spp. tested, Flexithrix dorotheae, and seven (most strains) of the eight species of Flexibacter spp. All but 2 of the 19 strains of Saprospira grandis, but neither of the two other tested species of Saprospira, survived freezing to −196° without additives.Incorporation of 10% glycerol before freezing permitted survival of three of the sensitive strains of Flexibacter (F. aurantiacus copepodarum, F. flexilis iolanthae, and F. giganteus), but adversely affected two other species (F. elegans and F. ruber). Incorporation of 10% dimethyl sulphoxide (DMSO) had some similar effects. Freezing to −196° with glycerol conserved viable cultures of all 19 S. grandis strains, of S. toviformis, and of 2 of the 3 strains of S. thermalis.A less extreme temperature was less satisfactory. Stored at −22°, some or all strains of 6 species died out in less than 1 week; most strains of 12 others died after a few weeks; and 7 species survived for at least 21 weeks. (The other three were not tested.)

SUMMARY: A method of Adansonian taxonomy was applied to a set of flexuous, gliding bacteria. A clustering of strains which corresponded to Saprospira grandis, Flexibacter flexilis, Saprospira thermalis, Flexibacter giganteus and Flexibacter roseolus was observed from the computed data. High similarity values (> 80 %) were found for strains assigned to the genera Cytophaga, Flexibacter and Microscilla.

A new species of flexibacterium, Saprospira toviformis, is described. It was isolated from marine littoral sand from New Zealand. It differs from S. grandis Gross by its more yellow color, more sluggish motility, and a number of minor physiological features. The content of guanine and cytosine, in the DNA of S. toviformis is 38% (as molar percent); the corresponding value for S. grandis is 48%.

FIVE strains of Saprospira grandis Gross, an apochlorotic cyanophyte or flexibacterium, have been isolated in pure culture from several marine littoral habitats around the United States1. In all strains the filaments tend to fragment and the individual cells to lyse at the end of the growing period. For example, a 10-ml. culture in a 50-ml. flask, grown in a sea-water medium containing 5 g/l. tryptone and 5 g/l. yeast extract (Difco) and shaken gently but constantly at 30°, forms within 1–2 days after inoculation a dense peach-coloured suspension with a satiny sheen; under the microscope it is seen to be full of helical filaments. A day or two later the sheen disappears, the colour becomes duller, and no microscopically intact or viable cells remain.