A new nitrogen-fixing <i>Clostridium</i> species from a high Arctic ecosystem

Jordan, D. C.; McNicol, Patricia J.

doi:10.1139/m79-144

Cited by 15 publications

(7 citation statements)

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“…Psychrotolerant micro‐organisms have been isolated previously from permanently cold Arctic or Antarctic environments ( Jordan and McNicol 1979; Mountfort et al . 1997) and, because of their ability to tolerate higher temperatures, from seasonally cold environments (Kotsyurbenko et al .…”

Section: Introductionmentioning

confidence: 99%

“…Psychrotolerant micro-organisms have been isolated previously from permanently cold Arctic or Antarctic environments ( Jordan and McNicol 1979;Mountfort et al 1997) and, because of their ability to tolerate higher temperatures, from seasonally cold environments (Kotsyurbenko et al 1995). Although psychrophilic micro-organisms are frequently unable to proliferate at temperatures above 22°C, their spores survive exposure to sub-optimal environmental conditions, including elevated temperatures.…”

Section: Introductionmentioning

confidence: 99%

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The abattoir source of culturable psychrophilic Clostridium spp. causing 'blown pack' spoilage of vacuum-packed chilled venison

et al. 2002

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Aims: To identify the abattoir source(s) of culturable psychrophilic clostridia causing 'blown pack' spoilage of vacuum-packed chilled meats. Methods and Results: Psychrophilic and psychrotolerant clostridia were isolated from hides, faeces and tonsils of deer slaughter stock, and from a meat plant environment. The isolates were differentiated using restriction fragment length polymorphism analysis of the 16S rDNA gene (PCR-RFLP) and 16S-23S rDNA internal transcribed spacer (ITS) analysis. PCR-RFLP group I clostridia were found to have restriction patterns indistinguishable from the patterns of 'blown pack'-causing Clostridium gasigenes DB1A T and R26. Gas production in packs inoculated with vegetative cells of PCR-RFLP group I clostridia was first evident after 14 days at 2°C. The prevalence of these clostridia was similar in hide and faecal samples from slaughter animals, but these micro-organisms were absent from tonsils and the meat plant environment. Banding patterns of PCR-RFLP group II clostridia showed some cross-similarity with patterns of the 'blown pack'-causing micro-organism Cl. estertheticum DSM 8809 T and Cl. estertheticumlike meat strains. The majority of clostridia in PCR-RFLP group II were found in the faeces of slaughter animals. Isolates representing PCR-RFLP group II did not, however, produce gas in vacuum packs stored at 2°C for 84 days. Conclusions: The data suggest that soil particles attached to hide or present in faeces are the most probable primary reservoir from which 'blown pack' clostridia are introduced onto carcasses. Therefore, dressing procedure hygiene remains paramount in order to control the spread of psychrophilic Clostridium spp. in a meat plant. Significance and Impact of the Study: The paper provides information critical for controlling 'blown pack' spoilage in meat processing plants. It reports on the use of molecular techniques for determination of abattoir sources of 'blown pack'-causing clostridia.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The abattoir source of culturable psychrophilic Clostridium spp. causing 'blown pack' spoilage of vacuum-packed chilled venison

et al. 2002

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“…As a first step to understand the structural basis of cold adaptation of psychrophilic enzymes, we have carried out biochemical and structural studies of malate dehydrogenase from Aquaspillium arcticum, a psychrophilic bacterium that was isolated from Arctic sediments and grows optimally at 4°C (11). MDH 1 is a homodimeric enzyme that catalyzes the reversible oxidation of malate to oxaloacetate in the presence of NAD in the citric acid cycle and thus plays a major role in central metabolism (12).…”

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confidence: 99%

Structural Basis for Cold Adaptation

Kim

Hwang

Kim³

et al. 1999

Journal of Biological Chemistry

162

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Aquaspillium arcticum is a psychrophilic bacterium that was isolated from arctic sediment and grows optimally at 4°C. We have cloned, purified, and characterized malate dehydrogenase from A. arcticum (Aa MDH). We also have determined the crystal structures of apo-Aa MDH, Aa MDH⅐NADH binary complex, and Aa MDH⅐NAD⅐oxaloacetate ternary complex at 1.9-, 2.1-, and 2.5-Å resolutions, respectively. The Aa MDH sequence is most closely related to the sequence of a thermophilic MDH from Thermus flavus (Tf MDH), showing 61% sequence identity and over 90% sequence similarity. Stability studies show that Aa MDH has a half-life of 10 min at 55°C, whereas Tf MDH is fully active at 90°C for 1 h. Aa MDH shows 2-3-fold higher catalytic efficiency compared with a mesophilic or a thermophilic MDH at the temperature range 4 -10°C. Structural comparison of Aa MDH and Tf MDH suggests that the increased relative flexibility of active site residues, favorable surface charge distribution for substrate and cofactor, and the reduced intersubunit ion pair interactions may be the major factors for the efficient catalytic activity of Aa MDH at low temperatures.Psychrophiles grow at low temperatures, where most of other organisms cannot grow. In order to survive such extreme environments (less than 4°C), enzymes from psychrophiles must catalyze efficiently at low temperatures (1-6). While good progress is being made to elucidate the adaptation mechanism of enzymes from some extremophiles including hyperthermophile, the molecular basis of cold adaptation of psychrophilic enzymes is relatively poorly understood (7-9). However, psychrophilic enzymes have generated considerable interest, since they can be used to improve the efficiency of industrial processes and for environmental applications (1, 10). Also, comparison of the structures of psychrophilic enzymes with mesophilic, thermophilic, and hyperthermophilic counterparts may add new insights into the understanding of catalytic mechanism and analysis of thermostability factors.As a first step to understand the structural basis of cold adaptation of psychrophilic enzymes, we have carried out biochemical and structural studies of malate dehydrogenase from Aquaspillium arcticum, a psychrophilic bacterium that was isolated from Arctic sediments and grows optimally at 4°C (11).MDH 1 is a homodimeric enzyme that catalyzes the reversible oxidation of malate to oxaloacetate in the presence of NAD in the citric acid cycle and thus plays a major role in central metabolism (12). Therefore, a certain amount of MDH is always expected to be present in most living organisms. Several MDHs from different sources have been extensively studied in genetic and biochemical aspects; sequences of a large number of malate dehydrogenases from organisms representing Archea, Bacteria, and Eukarya have been reported, and many of their gene products have been characterized. Furthermore, crystal structures of MDHs from the thermophile Thermus flavus (13), the mesophile Escherichia coli (14, 15), porcine heart mytochondria ...

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“…Strain SPL73 T , with its multilayer thin-section profile of cell wall, its GjC content of 38n4 mol % and its phylogenetic placement in cluster XIVa, can be readily differentiated from non-proteolytic Clostridium botulinum types B, E and F (Cato et al, 1986), Clostridium estertheticum (Collins et al, 1992), Clostridium algidicarnis (Lawson et al, 1994), Clostridium vincentii (Mountfort et al, 1997), Clostridium frigidicarnis (Broda et al, 1999) and Clostridium gasigenes (Broda et al, 2000). This meat strain differs from Clostridium arcticum (which stains Gram-negative and is not yet characterized with respect to GjC content and phylogenetic placement) and from Clostridium fimetarium (which has a GjC content of 35n6 mol % and also lacks phylogeny data) by its ability to hydrolyse starch and ferment lactose, maltose, raffinose, rhamnose and sucrose (Jordan & McNicol, 1979 ;Kotsyurbenko et al, 1995). In ad- Rogers & Baecker (1991).…”

Section: Discussionmentioning

confidence: 99%