Clostridium paradoxum
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Fig. 1. Morphology of Clostridium paradoxum under different growth conditions. More in the text. |
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| Li , Mandelco & Wiegel , 1993 |
Clostridium paradoxum is a moderately thermophilic alkaliphilic bacterium that is assigned to the paraphyletic taxon of the clostridia. It was given the name paradoxum (from ancient Greek παράδοξον, unexpected, contradictory) because flagellated endospores occur with it.
Appearance
Clostridium paradoxum can form 2–6 perithric flagella and endospores . In static culture at the optimal temperature for the bacterium (56 ° C), it changes its cell shape as it goes through the growth phases (see Fig. 1).
Cells growing exponentially in liquid culture (pH 10.1) are initially 2–4.5 µm long and rod-shaped (Fig. 1. A). In the late exponential phase, spore formation begins (B and C). It comes to an end in the stationary phase (D). Then also partially flagellated L-forms appear (E). Then the spores are released (F).
At the edge of the pH maximum pH 11, the bacteria grow as filaments (G) with a length of up to 50 µm. The effect also occurs when the cells are cultivated at the maximum temperature of approx. 60–63 ° C.
Growth and metabolism
Clostridium paradoxum is obligately anaerobic and grows in pure culture only on oxygen-free media. It cannot reduce sulfate.
The bacterium uses chemotrophic yeast extract and tryptone.
- Usable substrates (with the addition of 0.3% yeast extract): glucose , fructose , sucrose , maltose and pyruvate .
- Not usable u. a .: glycerine , lactic acid , formic acid , starch , cellulose , ethanol , methanol , amino acids .
Degradation products at pH values between 7.5 and 10 are mainly acetate , CO 2 and H 2 . The bacterium gains energy through fermentation and not through chemiosmotic- driven ATP synthases .
The organism grows at pH values between 7.0 and 11.1. The optimum is pH 10.1. At this pH value, the bacterium grows at temperatures between 30 ° C and 63 ° C, the optimum is 56 ° C. Under optimal conditions, the bacterium grows with a generation time of 16 minutes.
The molecular basis for the tolerance to alkaline media of Clostridium paradoxum is dealt with in
Occurrence
Clostridium paradoxum and physiologically similar strains have been found in activated sludge and digested sludge samples taken from sewage treatment plants in various US cities . In this biotope, anaerobic conditions regularly occur for the organisms. The optimal temperatures and pH values for Clostridium paradoxum were never measured there.
Chemotaxonomic Characteristics and External Taxonomy
Clostridium paradoxum has no lipopolysaccharides and is therefore assigned to the Gram- positive organisms, even if it reacts negatively to the Gram stain . It shows neither noticeable sensitivity to antibiotics nor resistance to most other clostridia. No heme could be detected.
The GC content of the genomic DNA is approx. 30 mol%.
The taxonomic assignment is based on the 16S RNA sequence. For the first description, the provisional generic name Clostridium was chosen because the authors expected a comprehensive taxonomic restructuring of the Clostridia soon. It is not yet completed (2015).
In the clostridia, 19 genetically clearly demarcated clusters were found to which the individual genera can be assigned. Clostridium paradoxum (in cluster XI), although it is currently assigned to the genus Clostridium within the Clostridiaceae , then belongs to the monophyletic family of the Peptostreptococcaceae and is closely related to the intestinal bacterium Peptrostreptococcus anaerobius :
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Type strain is JW-YL-7 (DSM 7308).
literature
- Rainey FA, Ward-Rainey NL, Janssen PH, Hippe H, Stackebrandt E: Clostridium paradoxum DSM 7308T contains multiple 16S rRNA genes with heterogeneous intervening sequences. . In: Microbiology . 142, No. 8, 1996, pp. 2087-95. doi : 10.1099 / 13500872-142-8-2087 . PMID 8760921 .
- Cook, Gregory M., et al .: The Intracellular pH of Clostridium paradoxum, an Anaerobic, Alkaliphilic, and Thermophilic Bacterium. Applied and environmental microbiology 62.12 (1996): 4576-4579.
- SA Ferguson, S. Keis, GM Cook: Biochemical and Molecular Characterization of a Na + -Translocating F1Fo-ATPase from the Thermoalkaliphilic Bacterium Clostridium paradoxum . In: Journal of Bacteriology . 188, No. 14, 2006, ISSN 0021-9193 , pp. 5045-5054. doi : 10.1128 / JB.00128-06 .
credentials
- ↑ Li, Youhong, Mandelco, Linda, Wiegel, Juergen: Isolation and Characterization of a Moderately Thermophilic Anaerobic Alkaliphile, Clostridium paradoxum sp. nov. ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. 1993 International Journal of Systematic and Evolutionary Microbiology, 43.3 pp. 450-460. doi : 10.1099 / 00207713-43-3-450
- ^ Ludwig, Wolfgang, Karl-Heinz Schleifer, and William B. Whitman. Revised road map to the phylumFirmicutes. Bergey's Manual® of Systematic Bacteriology. Springer New York, 2009. 1-13. Archive link ( Memento of the original from July 1, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (P. 10)
- ↑ COLLINS M, LAWSON P, WILLEMS A, CORDOBA J, FERNANDEZ-GARAYZABAL J, GARCIA P, CAI J, HIPPE H, FARROW: The Phylogeny of the Genus Clostridium: Proposal of Five New Genera and Eleven New Species Combinations. Int J Syst Evol Microbiol 44 (4): 812-826 doi : 10.1099 / 00207713-44-4-812
- ^ Y. Li, L. Mandelco, J. Wiegel: Isolation and Characterization of a Moderately Thermophilic Anaerobic Alkaliphile, Clostridium paradoxum sp. nov. . In: International Journal of Systematic Bacteriology . 43, No. 3, 1993, ISSN 0020-7713 , pp. 450-460. doi : 10.1099 / 00207713-43-3-450 .
