HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Supplementary Figures Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Anil Kumar, P. Articles by Ramana, Ch. V. Search for Related Content PubMed PubMed Citation Articles by Anil Kumar, P. Articles by Ramana, Ch. V. Agricola Articles by Anil Kumar, P. Articles by Ramana, Ch. V.

Rhodobacter changlensis sp. nov., a psychrotolerant, phototrophic alphaproteobacterium from the Himalayas of India

¹ Bacterial Discovery Laboratory, Centre for Environment, Institute of Science and Technology, J. N. T. University, Kukatpally, Hyderabad 500 085, India
² Department of Plant Sciences, School of Life Sciences, University of Hyderabad, PO Central University, Hyderabad 500 046, India

Correspondence
Ch. V. Ramana
r449{at}sify.com
or
sasi449{at}yahoo.ie

	ABSTRACT

TOP ABSTRACT MAIN TEXT REFERENCES

 
A Gram-negative, non-motile, oval to rod-shaped, psychrotolerant, phototrophic, purple non-sulfur bacterium (designated strain JA139^T) was isolated from a snow sample from Changla Pass in the Indian Himalayas. Strain JA139^T had vesicular-type intracytoplasmic membrane structures and contained bacteriochlorophyll a and most probably spheroidene-like carotenoids. Biotin, niacin and thiamine were required for growth of strain JA139^T. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that the strain clustered with species of the genus Rhodobacter but was distinctly separate from all recognized members of the family Rhodobacteraceae. Based on the genotypic and phenotypic differences observed between strain JA139^T and recognized Rhodobacter species, strain JA139^T is considered to represent a novel species of the genus, for which the name Rhodobacter changlensis sp. nov. is proposed. The type strain is JA139^T (=DSM 18774^T =CCUG 53722^T =JCM 14338^T).

A photograph showing the yellowish-brown-coloured snow sample collected from Changla Pass, Indian Himalayas, from where strain JA139^T was isolated, a phase-contrast micrograph of cells of strain JA139^T and the whole-cell absorption spectrum of strain JA139^T are available as supplementary material with the online version of this paper.

	MAIN TEXT

TOP ABSTRACT MAIN TEXT REFERENCES

 
Anoxygenic phototrophic bacteria are found widely distributed in various habitats including those from the extreme cold. Among such species reported from cold environments are Rhodoferax antarcticus (Madigan et al., 2000) isolated from an Antarctic microbial mat and Rhodoferax ferrireducens (Finneran et al., 2003) isolated from subsurface marine sediments of Oyster Bay, USA, both of which represent phototrophic members of the class Betaproteobacteria. Here we describe a novel psychrotolerant phototroph belonging to the genus Rhodobacter (class Alphaproteobacteria).

Strain JA139^T was isolated from photoheterotrophic enrichments of a snow sample from Changla Pass in the Himalayas of India. Purification and polyphasic taxonomic studies were carried out as described by Srinivas et al. (2006). Sequences were aligned by using the CLUSTAL X program (Thompson et al., 1997) and the alignment was corrected manually. The CLUSTAL X alignment file was used as input file to the SEQBOOT program in the PHYLIP package and the output file of SEQBOOT was used as the input file for maximum-likelihood analysis based on 100 datasets and five times jumbling. One single tree was produced by using 100 trees generated during maximum-likelihood analysis with the CONSENSE program. A final dendrogram with evolutionary distances was contructed by taking the alignment.phy file as the infile and the consensus tree as the intree in the maximum-likelihood program within the PHYLIP package (Felsenstein, 1989).

A yellowish-brown-coloured snow sample (see Supplementary Fig. S1 in IJSEM Online) was collected on 22 May 2006 from Changla Pass (5640 m above sea level) in the Indian Himalayas (3 ° 10' N 7 ° 16' E). Individual cells of strain JA139^T were oval to rod shaped, 0.8–1.0 µm wide and 2–4 µm long, and usually formed chains; they were non-motile and multiplied by binary fission (Supplementary Fig. S2). Electron micrographs of ultrathin sections of the cells revealed vesicular-type intracytoplasmic membrane structures.

Strain JA139^T was able to grow photo-organoheterotrophically [anaerobically in the light (2400 lx)] and chemo-organoheterotrophically [aerobically in the dark, with pyruvate (0.3 %, w/v)]. We were unable to demonstrate photolithoautotrophy [anaerobically in the light (2400 lx), with Na₂S (0.5 mM), Na₂S₂O₃ . 5H₂O (0.5 mM) or NaHCO₃ (0.1 %, w/v)], chemolithoautotrophy [aerobically in the dark, with thiosulfate (0.5 mM) or NaHCO₃ (0.1 %, w/v)] or fermentative growth [anaerobically in the dark, with pyruvate (0.3 % w/v)] for strain JA139^T. Substrates that could be utilized as carbon/electron donors under photo-organoheterotrophic conditions at 28±2 °C included pyruvate, 2-oxoglutarate, succinate, glucose, mannitol, sorbitol, glutamate, casein hydrolysate, yeast extract and peptone (see Table 1). Formate, acetate, propionate, butyrate, valerate, crotonate, caproate, caprylate, lactate, gluconate, glycolate, benzoate, tartrate, malate, fumarate, citrate, fructose, sucrose, lactose, starch, glycerol, aspartate, methionine, cysteine, ascorbate, methanol, ethanol, propanol and butanol could not be utilized. Strain JA139^T was able to use ammonium chloride, glutamine and N₂ as nitrogen sources, but not urea, nitrate or nitrite. Sulfate and thioglycolate were utilized as sulfur sources, but not sulfite, sulfur, sulfide, thiosulfate or cysteine. Although NaCl was not obligatory for growth of strain JA139^T, optimum growth occurred at 0.1 % (w/v). The pH range for growth of strain JA139^T was 6.5–9 with an optimum at pH 6.5–7.5. The optimum temperature for growth was 28±2 °C, but growth was observed from 5 to 32 °C. The biomass yield of strain JA139^T grown at 5 °C was about 50 % of that grown at the optimum temperature. Strain JA139^T grew well in the presence of fluorescent light (optimum light intensity 2000 lx; range 1000–3000 lx). Furthermore, strain JA139^T required biotin, niacin and thiamine as growth factors. The photosynthetically grown cell suspension was yellowish brown. The whole-cell absorption spectrum of strain JA139^T gave absorption maxima at 380, 407, 450, 470, 512, 590, 806 and 851 nm, confirming the presence of bacteriochlorophyll a, and most probably carotenoids of the spheroidene series (Supplementary Fig. S3). The DNA base composition of strain JA139^T was 69.4 mol% G+C (by HPLC). The phylogenetic relationship of strain JA139^T to other purple non-sulfur bacteria was examined by 16S rRNA gene sequencing. The data obtained revealed that the new isolate branched separately but clustered with the type strains of species of the genus Rhodobacter and was distinct from other genera of purple non-sulfur bacteria. Strain JA139^T showed highest 16S rRNA gene sequence similarities with the type strains of Rhodobacter sphaeroides (94.6 %), Rhodobacter azotoformans (94.4 %), Rhodobacter veldkampii (93.6 %), Rhodobacter blasticus (92.7 %), Rhodobacter capsulatus (92.5 %) and Rhodobacter vinaykumarii (93.1 %; Srinivas et al., 2007) (Fig. 1). In addition to showing 16S rRNA gene sequence divergence, strain JA139^T showed clear phenotypic differences from recognized Rhodobacter species (Table 1) that justify the description of this strain as representing a novel species, for which the name Rhodobacter changlensis sp. nov. is proposed.

View larger version (41K): [in this window] [in a new window]   Fig. 1. Dendrogram depicting the phylogenetic relationships of strain JA139T within the family Rhodobacteraceae determined by using 16S rRNA gene sequence analysis. Bar, 1 substitution per 100 nucleotide positions.

Cells are oval to rod-shaped, 0.8–1.0 µm wide and 2–4 µm long, are non-motile and divide by binary fission, and occasionally form chains. Growth occurs under anaerobic conditions in the light (photo-organoheterotrophy) or under aerobic conditions in the dark (chemo-organoheterotrophy). Internal photosynthetic membranes are of the vesicular type. Phototrophic cultures are yellowish brown. The in vivo absorption spectrum of intact cells in sucrose exhibits maxima at 380, 407, 450, 470, 512, 590, 806 and 851 nm, confirming the presence of bacteriochlorophyll a and most probably carotenoids of the spheroidene series. The organism is psychrotolerant (range 5–32 °C; optimum at 28±2 °C), has a pH optimum at 6.5–7.5 and does not require NaCl for growth. Photo-organoheterotrophy with a few organic compounds is the preferred mode of growth. Grows well on pyruvate, 2-oxoglutarate, mannitol and sorbitol as carbon sources. Growth is also observed on succinate, glucose, glutamate, casein hydrolysate, yeast extract and peptone. Chemoautotrophic growth is not possible in the presence of thiosulfate/hydrogen as electron donor and NaHCO₃ as carbon source. Fermentative growth is not possible in the presence of pyruvate as fermentable carbon source. Biotin, niacin and thiamine are required as growth factors. DNA base composition is 69.4 mol% G+C (by HPLC).

The type strain, JA139^T (=DSM 18774^T =CCUG 53722^T =JCM 14338^T), was isolated from a snow sample collected from Changla Pass in the Indian Himalayas.

	ACKNOWLEDGEMENTS

 
Financial assistance was received from the Department of Biotechnology, Government of India. P. A. K. and T. N. R. S. acknowledge the CSIR, Government of India, for the award of SR fellowships.

	REFERENCES

TOP ABSTRACT MAIN TEXT REFERENCES

 
Felsenstein, J. (1989). PHYLIP (phylogeny inference package), version 3.5.1. Distributed by the author. Department of Genome Sciences, University of Washington, Seattle, USA.

Finneran, K. T., Johnsen, C. V. & Lovley, D. R. (2003). Rhodoferax ferrireducens sp. nov., a psychrotolerant, facultatively anaerobic bacterium that oxidizes acetate with the reduction of Fe (III). Int J Syst Evol Microbiol 53, 669–673.[Abstract/Free Full Text]

Madigan, M. T., Jung, D. O., Woese, C. R. & Achenbach, L. A. (2000). Rhodoferax antarcticus sp. nov., a moderately psychrophilic purple nonsulfur bacterium isolated from an Antarctic microbial mat. Arch Microbiol 173, 269–277.[CrossRef][Medline]

Srinivas, T. N. R., Anil Kumar, P., Sasikala, Ch., Ramana, Ch. V., Süling, J. & Imhoff, J. F. (2006). Rhodovulum marinum sp. nov., a novel phototrophic purple non-sulfur alphaproteobacterium from marine tides of Visakhapatnam, India. Int J Syst Evol Microbiol 56, 1651–1656.[Abstract/Free Full Text]

Srinivas, T. N. R., Anil Kumar, P., Sasikala, Ch., Ramana, Ch. V. & Imhoff, J. F. (2007). Rhodobacter vinaykumarii sp. nov., a marine phototrophic alphaproteobacterium from tidal waters, and emended description of the genus Rhodobacter. Int J Syst Evol Microbiol 57, 1984–1987.[Abstract/Free Full Text]

Thompson, J. D., Higgins, D. G., Gibson, T. J., Plewniak, F., Jeanmougin, F. & Higgins, D. J. (1997). The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. Nucleic Acids Res 25, 4876–4882.[Abstract/Free Full Text]

This article has been cited by other articles:

				V. Venkata Ramana, P. Anil Kumar, T. N. R. Srinivas, Ch. Sasikala, and Ch. V. Ramana Rhodobacter aestuarii sp. nov., a phototrophic alphaproteobacterium isolated from an estuarine environment Int J Syst Evol Microbiol, May 1, 2009; 59(5): 1133 - 1136. [Abstract] [Full Text] [PDF]

				K. Arunasri, V. Venkata Ramana, C. Sproer, Ch. Sasikala, and Ch. V. Ramana Rhodobacter megalophilus sp. nov., a phototroph from the Indian Himalayas possessing a wide temperature range for growth Int J Syst Evol Microbiol, August 1, 2008; 58(8): 1792 - 1796. [Abstract] [Full Text] [PDF]

				V. Venkata Ramana, Ch. Sasikala, and Ch. V. Ramana Rhodobacter maris sp. nov., a phototrophic alphaproteobacterium isolated from a marine habitat of India Int J Syst Evol Microbiol, July 1, 2008; 58(7): 1719 - 1722. [Abstract] [Full Text] [PDF]

				T. N. R. Srinivas, P. Anil Kumar, Ch. Sasikala, C. Sproer, and Ch. V. Ramana Rhodobacter ovatus sp. nov., a phototrophic alphaproteobacterium isolated from a polluted pond Int J Syst Evol Microbiol, June 1, 2008; 58(6): 1379 - 1383. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Supplementary Figures Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Anil Kumar, P. Articles by Ramana, Ch. V. Search for Related Content PubMed PubMed Citation Articles by Anil Kumar, P. Articles by Ramana, Ch. V. Agricola Articles by Anil Kumar, P. Articles by Ramana, Ch. V.