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1 GBF Gesellschaft für Biotechnologische Forschung mbH, Mascheroder Weg 1, D-38124 Braunschweig, Germany
2 DSMZ Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
Correspondence
Irene Wagner-Döbler
iwd{at}gbf.de
| ABSTRACT |
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The GenBank/EMBL/DDBJ accession number of the 16S rRNA gene sequence of strain DFL-43T is AJ582088.
The phylogenetic position of strains DFL-43T and DFL-44 within the
-2 subgroup of the Alphaproteobacteria is shown in a supplementary figure available in IJSEM Online.
Present address: Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB), Alte Fischerhütte 2, D-16775 Stechlin-Neuglobsow, Germany. ![]()
| MAIN TEXT |
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Here we describe a group consisting of five strains that belong to the
-2 subgroup of the Proteobacteria and which initially showed the greatest level of 16S rRNA gene sequence similarity with Ahrensia kielensis (Ahrens, 1968
; Uchino et al., 1998
). However, after our phenotypic characterization of these novel strains was completed, the first description of the micro-organism Hoeflea marina was published by Peix et al. (2005)
. On the basis of 16S rRNA gene sequences, the novel strains were found to be more closely related to H. marina than to A. kielensis. Both A. kielensis and H. marina were originally described by Ahrens (1968)
as marine Agrobacterium species forming star-shaped aggregates and were subsequently reclassified (Rüger & Höfle, 1992
; Uchino et al., 1998
; Peix et al., 2005
). In contrast to related genera and species, the novel strains in this study were able to form photosynthetic pigments, in particular bacteriochlorophyll a, if appropriate conditions were provided.
The isolates were obtained from cultures of marine dinoflagellates. Three strains (DFL-13, DFL-33 and DFL-44) were from Alexandrium lusitanicum ME207 and two strains (DFL-42 and DFL-43T) were from Prorocentrum lima ME130. Both cultures were maintained in the dinoflagellate collection of the Biological Institute of the island of Helgoland (German Bight). Single algal cells were washed and plated onto agar plates prepared with 10-fold-diluted Difco marine broth 2216. Strains DFL-43T and DFL-44 were selected for further characterization.
Colonies of surface cultures were light-beige on full-strength marine broth 2216 (Difco) and wine-red on 10-fold-diluted marine broth. They were of a smooth consistency, relatively flat and exhibited an opaque centre and a translucent halo. The cells were small, short, rods, 0·30·5x0·72·0 µm (Fig. 1c
) and showed rapid movement. Electron micrographs of shadow-cast cells of strain DFL-43T showed monotrichous flagellation at one or both poles (Fig. 1a
). In strain DFL-43T, distinct capsules were visible around the cells. Ultrathin sections revealed a typical Gram-negative cell-wall structure (Fig. 1b
).
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The utilization of carbon sources was checked in a mineral sea-water medium containing 0·1 g yeast extract l1 to provide the required growth factors. The following carbon sources were tested at a concentration of 1 g l1 (acids as sodium salts): acetate, butyrate, succinate, fumarate, malate, lactate, citrate, glutamate, pyruvate, glucose, fructose, ethanol, methanol, glycerol and yeast extract. Moderate growth was obtained only with yeast extract and with acetate or malate. The other substrates tested allowed only limited growth, with OD600 values ranging from 20 (glucose) to 60 % (fumarate, citrate) of that of the acetate culture; methanol and ethanol did not allow any growth at all. In this respect, the novel strains resemble the type strain of A. kielensis, which did not use any of the carbon sources tested (Rüger & Höfle, 1992
). H. marina was found to use a series of sugars and sugar alcohols, including glucose (Peix et al., 2005
). Experiments involving culture of the cells with acetate as the substrate and several additives, e.g. yeast extract (0·1 g l1), vitamin-free and vitamin-containing Casamino acids (0·25 g l1; Difco) as well as a vitamin solution (consisting of biotin, thiamine, nicotinic acid, pantothenic acid, vitamin B12, pyridoxine and 6-aminobenzoic acid), showed that growth factors were required. These growth factors were provided by yeast extract, but not by any of the administered vitamins and amino acids.
The novel strains were unable to decompose or liquefy any of the following polymers: starch, alginate, gelatin and Tween 80 (for lipase activity). They were positive for catalase and oxidase activity, did not form indole from tryptophan and were unable to form nitrite and nitrogen from nitrate under air-exclusion conditions. Antibiotic inhibition was observed with penicillin G, tetracycline and chloramphenicol, but not with polymyxin B. Anaerobic growth by the fermentation of glucose was not observed, but there was some sensitivity to full oxygen exposure, as the growth zone in agar deep culture was distinctly below the surface. No growth occurred under anaerobic conditions in the light when acetate was the substrate.
In several aerobic phototrophic bacteria (exclusively freshwater organisms), reduction of toxic potassium tellurite to inert elemental tellurium (deposited in the cytoplasm) has been observed (Yurkov et al., 1996
). Strains DFL-43T and DFL-44 also possessed this capability. After 4 days growth in peptone medium to which 0·051 g l1 potassium tellurite had been added, cultures turned jet-black and refractile inclusions were visible in the cells.
Cellular fatty acids were determined as described by Labrenz et al. (1998)
. The percentages of fatty acids found in strain DFL-43T and in H. marina and A. kielensis are shown in Table 1
. Strain DFL-44 had almost the same values as strain DFL-43T. As is usually the case for the Alphaproteobacteria, the mono-unsaturated straight chain acid 18 : 1
7 was the major component (6385 %), replaced, in part, by the methylated form, particularly in strain DFL-43T (21 %). Strain DFL-43T, H. marina and A. kielensis all contained the saturated acids 16 : 0 and 18 : 0, albeit in small amounts, whereas the fatty acids 16 : 1
7 and 19 : 1 cyclo were found only in strain DFL-43T and in H. marina. The type strain of A. kielensis contained a hydroxylated 12 : 0 acid and a 20 : 0 acid that were not found in either strain DFL-43T or H. marina. Polar lipids were extracted and separated by TLC according to Tindall (1990)
. For strain DFL-43T, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine were the predominant polar lipids. Moderate amounts of phosphatidylcholine and sulfoquinovosyldiacetylglycerol were present and only minor amounts of diphosphatidylglycerol and an unknown amino lipid were found. Interestingly, A. kielensis contained the same lipids, albeit in somewhat different proportions; in particular, the amount of phosphatidylethanolamine was much lower. H. marina differed from the other strains in that it lacked phosphatidylcholine.
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Even though the first variable region of the 16S rRNA gene sequences of strains DFL-43T and DFL-44 was more closely related to that of A. kielensis, the almost-complete 16S rRNA gene sequences of the novel strains revealed them to be most closely related to H. marina. The phylogenetic position of strain DFL-43T as a novel member within the family Phyllobacteriaceae is shown in Fig. 3
. Its phylogenetic position within the
-2 subgroup of the Alphaproteobacteria is shown in Supplementary Fig. S1, available in IJSEM Online.
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Cells are small rods, 0·30·5x0·72·0 µm in size and are motile by means of single, polarly inserted flagella. Colonies grown on marine agar 2216 are smooth, flat and may form an opaque centre and a translucent halo. They are colourless to slightly beige if grown in the light. Cultures require microaerobic growth conditions, but do not grow anaerobically. Growth occurs at concentrations of sea salts from 0·57·0 %, at temperatures of up to 33 °C (optimum, 31 °C) and at pH values in the range 69. Acetate and malate are good growth substrates, whereas succinate, fumarate, lactate, citrate, glutamate, pyruvate, glucose, fructose and glycerol allow only poor growth; ethanol and methanol are not used. Yeast extract is required for growth. Gelatin, starch, alginate and Tween 80 are not decomposed. Nitrate is not reduced to nitrite or nitrogen. Indole is not formed from tryptophan. Cells contain bacteriochlorophyll a and a carotenoid, probably spheroidenone, in small to medium amounts. The DNA G+C content of the type strain is 59·3 mol%.
The type strain, DFL-43T (=DSM 17068T=NCIMB 14078T), was isolated from a culture of Prorocentrum lima (dinoflagellates).
| ACKNOWLEDGEMENTS |
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| REFERENCES |
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Allgaier, M., Uphoff, H., Felske, A. & Wagner-Döbler, I. (2003). Aerobic anoxygenic photosynthesis in Roseobacter clade bacteria from diverse marine habitats. Appl Environ Microbiol 69, 50515059.
Biebl, H., Tindall, B. J., Koblizek, M., Lünsdorf, H., Pukall, R. & Wagner-Döbler, I. (2005). Dinoroseobacter shibae gen. nov., sp. nov., a new aerobic phototrophic bacterium isolated from dinoflagellates. Int J Syst Evol Microbiol 55, 10891096.
Felsenstein, J. (1993). PHYLIP (phylogeny inference package), version 3.5.1. Distributed by the author. Department of Genome Sciences, University of Washington, Seattle, WA, USA.
Hall, T. A. (1999). BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symp Ser 41, 9598.
Kolber, Z. S., Plumley, F. G., Lang, A. S. & 7 other authors (2001). Contribution of aerobic photoheterotrophic bacteria to the carbon cycle in the ocean. Science 292, 24922495.
Labrenz, M., Collins, M. D., Lawson, P. A., Tindall, B. J., Schumann, P. & Hirsch, P. (1998). Antarctobacter heliothermus gen. nov., sp. nov., a budding bacterium from hypersaline and heliothermal Ekho Lake. Int J Syst Bacteriol 48, 13631372.
Maidak, B. L., Cole, J. R., Lilburn, T. G. & 7 other authors (2001). The RDP-II (Ribosomal Database Project). Nucleic Acids Res 29, 173174.
Peix, A., Rivas, R., Trujillo, M. E., Vancanneyt, M., Velazquez, E. & Willems, A. (2005). Reclassification of Agrobacterium ferrugineum LMG 128 as Hoeflea marina gen. nov., sp. nov. Int J Syst Evol Microbiol 55, 11631166.
Rüger, H.-J. & Höfle, M. (1992). Marine star-shaped-aggregate-forming bacteria: Agrobacterium atlanticum sp. nov.; Agrobacterium meteori sp. nov.; Agrobacterium ferrugineum sp. nov., nom rev.; Agrobacterium gelatinovorum sp. nov., nom. rev.; and Agrobacterium stellulatum sp. nov., nom. rev. Int J Syst Bacteriol 42, 133143.
Schwalbach, M. S. & Fuhrman, J. A. (2005). Wide-ranging abundance of aerobic anoxygenic phototrophic bacteria in the world ocean revealed by epifluorescence microscopy and quantitative PCR. Limnol Oceanogr 50, 620628.
Tindall, B. J. (1990). Lipid composition of Halobacterium lacusprofundi. FEMS Microbiol Lett 66, 199202.
Uchino, Y., Hirahata, A., Yakota, A. & Sugiyama, J. (1998). Reclassification of marine Agrobacterium species: proposals of Stappia stellulata gen. nov., comb. nov., Stappia aggregata sp. nov., nom. rev., Ruegeria atlantica gen. nov., comb. nov., Ruegeria gelatinovora comb. nov., Ruegeria algicola comb. nov., and Ahrensia kielensis gen. nov., sp. nov., nom. rev. J Gen Appl Microbiol 44, 201210.
Yurkov, V., Jappé, J. & Verméglio, A. (1996). Tellurite resistance by obligately aerobic photosynthetic bacteria. Appl Environ Microbiol 62, 41954198.[Abstract]
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