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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 75 (1990), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract In recent years the upper and lower temperature limits for growth of pure cultures of microorganisms have been extended at least to 110°C and −14°C, respectively. There are no organisms which grow at both 0°C and 100°C and, therefore, organisms are grouped according to their ranges of growth temperatures. Thus, the questions of importance are:: (1) What is the widest temperature range (temperature span) over which a single organism can grow? and (2) How much can one alter the temperature spans of an organism? The concept of ‘cryptic thermophiles’ is used to explain some of the published data on the latter question. A wider temperature range can be very important for organisms in various ways, since it makes an organism more versatile with regard to changes in the environment. Also, it enables the organism to utilize a wider range of ecological niches. Some aerobic and anaerobic extreme thermophiles will grow within a span of more than 40°C. Furthermore, such organisms are regarded suitable for biotechnological applications as well. The following hypothesis is presented and discussed: these organisms have two sets of key enzymes, and their synthesis is regulated by temperature. Such organisms are capable of growing in two different ranges, such as the mesophilic and thermophilic ranges. The hypothesis is based on the fact that these bacteria exhibit broken Arrhenius plots (growth temperature versus) doubling time as parameters), and is illustrated with ‘temperature tolerant extreme thermophiles’ as the major example. However, the hypothesis is not restricted to this group, but is also applicable to the ‘temperature tolerant thermophiles and mesophiles’.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 148 (1997), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The industrial application of thermophilic (eu)bacteria is hampered by the lack of genetic systems for these bacteria. We report here the first unequivocal transformation of a Gram-positive, thermophilic, anaerobic microorganism, Thermoanaerobacterium, with the kanamycin resistance-mediating plasmid pIKM1. The construct pIKM1 is based on the Escherichia coli–Clostridium acetobutylicum shuttle vector pIMP1 and contains the thermostable kanamycin cassette from S. faecalis plasmid pKD102. Using electrotransformation, plasmid pIKM1 mediated kanamycin resistance in Thermoanaerobacterium sp. strain JW/SL-YS485 up to 400 μg ml−1 at 48°C and 200 μg ml−1 at 60°C.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 32 (2000), S. 0 
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Under anaerobic conditions, microbial reductive dechlorination of polychlorinated biphenyls (PCBs) occurs in soils and aquatic sediments. In contrast to dechlorination of supplemented single congeners for which frequently ortho dechlorination has been observed, reductive dechlorination mainly attacks meta and/or para chlorines of PCB mixtures in contaminated sediments, although in a few instances ortho dechlorination of PCBs has been observed. Different microorganisms appear to be responsible for different dechlorination activities and the occurrence of various dehalogenation routes. No axenic cultures of an anaerobic microorganism have been obtained so far. Most probable number determinations indicate that the addition of PCB congeners, as potential electron acceptors, stimulates the growth of PCB-dechlorinating microorganisms. A few PCB-dechlorinating enrichment cultures have been obtained and partially characterized. Temperature, pH, availability of naturally occurring or of supplemented carbon sources, and the presence or absence of H2 or other electron donors and competing electron acceptors influence the dechlorination rate, extent and route of PCB dechlorination. We conclude from the sum of the experimental data that these factors influence apparently the composition of the active microbial community and thus the routes, the rates and the extent of the dehalogenation. The observed effects are due to the specificity of the dehalogenating bacteria which become active as well as changing interactions between the dehalogenating and non-dehalogenating bacteria. Important interactions include the induced changes in the formation and utilization of H2 by non-dechlorinating and dechlorinating bacteria, competition for substrates and other electron donors and acceptors, and changes in the formation of acidic fermentation products by heterotrophic and autotrophic acidogenic bacteria leading to changes in the pH of the sediments.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 15 (1982), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 67 (1990), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 13C-1 phenol was converted to 13C-4 benzoic acid by an anaerobic phenol converting enrichment, which did not form p-hydroxybenzoate as a free intermediate but converted p-hydroxybenzoate first phenol and then, probably by another organism, to benzoate. No isotopic effect was observed using D5- and D6-phenol, suggesting that the breakage of the C-H bond on the C-4 position was not a rate limiting step in the conversion.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Extremophiles 2 (1998), S. 257-267 
    ISSN: 1433-4909
    Keywords: Key words Alkaliphil* ; Anaerob* ; Thermophil* ; Clostridium paradoxum ; Clostridium thermoalkaliphilum ; Thermobrachium celere ; Anaerobranca horikoshii ; Thermosyntropha lipolytica ; Caloramator ; pH stasis ; Internal pH ; Isolation ; Phylogeny ; Biodiversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although some anaerobic and aerobic mesophiles have long been known to grow at alkaline pH (above 9.5), little was known until recently about thermophilic alkaliphiles, termed now alkalithermophiles. This minireview describes presently known and recently validly described anaerobic alkalithermophilic bacteria (pHopt 55C 〉 8.5; Topt 〉 55°C) and alkalitolerant thermophiles (pHopt 55C 〈 8.5 but pHmax 55C above 9.0). Some of these are widely distributed, but others have been isolated (thus far) only from one specific location. This novel group of anaerobic bacteria is comprised of physiologically different genera and species which, so far, all belong to the Gram-type positive Bacillus-Clostridium phylogenetic subbranch. An interesting feature of these anaerobic alkalithermophiles is that most of the isolates have short doubling times. The fastest growing among them are strains of Thermobrachium celere, with doubling times as short as 10 min while growing above pH 9.0 and above 55°C.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 37 (1992), S. 490-495 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A mutant strain of ‘Thermoanaerobacter ethanolicus’ (ATCC 31 550) designated JW200 Fe 4 contains primary and secondary alcohol dehydrogenases (ADHs). The primary ADH from JW000 Fe 4 was formed early in the growth cycle compared to the primary ADH form the wild-type strain (JW200 wt). The secondary ADH displayed 2.5-fold greater activity during the growth cycle of JW200 Fe 4 compared to the secondary ADH form JW200 wt. Both primary and secondary ADHs from JW200 Fe 4 were purified to homogeneity ADHs from JW200 Fe 4 were purified to homogeneity as determined by sodium dodecyl sulphate-gel electrophoresis. Relative molecular weight estimations indicated that both ADHs were tetrameric. Each ADH from JW200 Fe 4 contained approximately four Zn atoms per subunit and displayed Arrhenius plots similar to the ADHs from JW200 wt. The substrate specificity for the ADHs from JW200 Fe 4 was similar to that of the ADHs from JW200 wt. The secondary ADH oxidized 2-propanol at 51 times the rate of ethanol. Both ADHs from JW200 Fe 4 apparently reduce acetaldehyde to ethanol while only the secondary ADH from JW200 wt was suggested to contribute significantly to ethanol production.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1433-4909
    Keywords: Key words Fe(III) reduction ; Iron reduction ; Extreme thermophilic anaerobes ; Hydrogen oxidation ; Magnetite ; Siderite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Six sustainable enrichment cultures of thermophilic H2-oxidizing microorganisms utilizing Fe(III) as an electron acceptor were obtained from geothermally heated environments located on two continents (America, Eurasia) and on islands in the Northern (Iceland) and Southern (Fiji) hemispheres, demonstrating the wide distribution of these microorganisms. The main products of amorphic Fe(III) oxide reduction were magnetite and siderite. The observed temperature range for Fe(III) reduction in growing cultures was from 55°C to 87°C, extending the known limits for growth of Fe(III)-reducing microorganisms producing extracellular magnetite to nearly 90°C.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 47 (1997), S. 742-748 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The reductive dechlorination of 2,4- and 3,4-dichlorophenol (DCP) was studied in slurries of marine sediments and subsurface soils with dissolved organic carbon concentrations less than 1 ppm. Dechlorination was markedly greater in marine sediment slurries than in subsoil slurries, although similar products were observed in each case. From 25% to 98% of the 2,4- and 3,4-DCP (6.5 μm/l) added to most marine slurries was converted to 4- and 3-chlorophenol (CP) respectively, within 30 weeks. In contrast 2,4-DCP was dechlorinated to 4-CP (〉90%) in only 1 of 24 replicate subsoil slurries after 32 weeks of incubation. Dechlorination was observed within 2 weeks when yeast extract was added to subsoil slurries; yeast extract additions also stimulated dechlorination in marine sediments but to a lesser extent. The intermediate monochlorophenol products did not persist in marine slurries but did persist in the subsoil slurries. It was concluded that the total organic carbon at a site is not always a good predictor of the site's ability to support dechlorination activity.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 20 (1984), S. 59-65 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary During growth in the presence of fibers composed of cellulose or hemicellulose, various strains of the thermophilic soil bacterium Clostridium thermocellum and several newly isolated thermophilic anaerobic soil bacteria adhered to the fibers. Attachment occurred via a fibrous ruthenium red-staining material. C. thermocellum sporulated while attached to the fibers when the pH dropped below 6.4. It is postulated that the attachment is involved in cellulose breakdown and that C. thermocellum gaines an advantage by remaining attached to its insoluble substrates when the environment is not suitable for rapid growth. The tendency to adhere to cellulose fibers was used in the purification of thermophilic cellulolytic anaerobes.
    Type of Medium: Electronic Resource
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