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European Journal of Biochemistry Feb 1997A heat-labile beta-lactamase has been purified from culture supernatants of Psychrobacter immobilis A5 grown at 4 degrees C and the corresponding chromosomal ampC gene...
A heat-labile beta-lactamase has been purified from culture supernatants of Psychrobacter immobilis A5 grown at 4 degrees C and the corresponding chromosomal ampC gene has been cloned and sequenced. All structural and kinetic properties clearly relate this enzyme to class C beta-lactamases. The kinetic parameters of P. immobilis beta-lactamase for the hydrolysis of some beta-lactam antibiotics are in the same range as the values recorded for the highly specialized cephalosporinases from pathogenic mesophilic bacteria. By contrast, the enzyme displays a low apparent optimum temperature of activity and a reduced thermal stability. Structural factors responsible for the latter property were analysed from the three-dimensional structure built by homology modelling. The deletion of proline residues in loops, the low number of arginine-mediated H-bonds and aromatic-aromatic interactions, the lower global hydrophobicity and the improved solvent interactions through additional surface acidic residues appear to be the main determinants of the enzyme flexibility.
Topics: Adaptation, Physiological; Amino Acid Sequence; Antarctic Regions; Base Sequence; Chromosomes, Bacterial; Cold Temperature; Enzyme Stability; Genes, Bacterial; Gram-Negative Aerobic Bacteria; Hot Temperature; Molecular Sequence Data; beta-Lactamases
PubMed: 9063463
DOI: 10.1111/j.1432-1033.1997.00186.x -
International Journal of Systematic... Oct 1996Ornithogenic soil is derived from the deposition of the fecal matter of various species of birds and is a major source of nutrient input in the Antarctic marine...
Ornithogenic soil is derived from the deposition of the fecal matter of various species of birds and is a major source of nutrient input in the Antarctic marine ecosystem. A significant proportion of microbiota of ornithogenic soil collected from an Adélie penguin colony in eastern Antarctica (Vestfold Hills ice-free zone) consisted of gram-negative, coccoid bacteria identified on the basis of their phospholipid ester-linked fatty acid and lipid class profiles as Psychrobacter strains. Phenotypic, genotypic, and 16S ribosomal DNA phylogenetic analyses revealed that the Antarctic psychrobacters belonged to three distinct groups. Comparisons with Psychrobacter immobilis and Moraxella phenylpyruvica reference cultures isolated from fish, seawater, poultry, and human clinical specimens revealed the relationships of these groups within the genus Psychrobacter. Two of the groups represent the following two novel species: Psychrobacter urativorans sp. nov. (type strain, strain ACAM 534) and Psychrobacter frigidicola sp. nov. (type strain, strain ACAM 304). The third group of strains included members of the previously described species P. immobilis (Juni and Heym 1986). In addition, M. phenylpyruvica (Bøvre and Henriksen 1967) is renamed Psychrobacter phenylpyruvicus comb. nov. (type strain, strain ACAM 535) on the basis of 16S ribosomal DNA phylogenetic data. In general, the genus Psychrobacter could be differentiated from the related genera Moraxella and Acinetobacter by the fact that the members of the genus Psychrobacter are psychrotolerant or psychrophilic and halotolerant, which reflects the ubiquitous distribution of the genus in both marine and terrestrial environments. On the basis of the results of this and previous studies, the genus Psychrobacter is the predominant genus in ornithogenic soils in Antarctica and is diverse.
Topics: Antarctic Regions; Base Composition; Base Sequence; DNA, Ribosomal; Humans; Lipids; Molecular Sequence Data; Moraxella; Phenotype; RNA, Ribosomal, 16S; Soil Microbiology
PubMed: 8863407
DOI: 10.1099/00207713-46-4-841 -
Biochimica Et Biophysica Acta Jan 1993A lipase gene (lip1) from the facultative psychrophilic strain Psychrobacter immobilis B10 has been cloned and sequenced. The deduced preprotein sequence is composed of...
A lipase gene (lip1) from the facultative psychrophilic strain Psychrobacter immobilis B10 has been cloned and sequenced. The deduced preprotein sequence is composed of 317 amino acids with a predicted M(r) of 35,288. A primary structure alignment of lipases including lip1 shows conserved elements for which a structural role is proposed in the light of recent crystallographic studies. The analysis of the psychrophilic enzyme sequence suggests characteristics in relation with the adaptation to cold.
Topics: Amino Acid Sequence; Base Sequence; Cloning, Molecular; Cold Temperature; Genes, Bacterial; Lipase; Molecular Sequence Data
PubMed: 7916627
DOI: 10.1016/0167-4781(93)90078-r -
Journal of Clinical Microbiology Feb 1990The name Psychrobacter immobilis recently has been proposed for a group of chiefly psychrotrophic, aerobic, gram-negative, nonmotile, oxidase-positive coccobacilli...
The name Psychrobacter immobilis recently has been proposed for a group of chiefly psychrotrophic, aerobic, gram-negative, nonmotile, oxidase-positive coccobacilli commonly found associated with fish, processed meat, and poultry products. This article reports an ocular infection in a 12-day-old newborn who acquired the infection in the hospital, probably because of frequent manipulations in a closed aerated incubator. Also, this report intends to alert microbiologists to opportunistic infections that might be confused with infections caused by unusual oxidase-positive, gram-negative diplococci and to the isolation of P. immobilis from a human infection.
Topics: Cross Infection; Eye Infections, Bacterial; Gram-Negative Aerobic Bacteria; Humans; Infant, Newborn; Male; Water Microbiology
PubMed: 2312690
DOI: 10.1128/jcm.28.2.400-401.1990 -
Journal of Food Protection Mar 2000Three phenotypic identification systems were employed to identify 106 strains of gram-negative, nonmotile, aerobic bacteria obtained during iced storage of wild (Salmo...
Three phenotypic identification systems were employed to identify 106 strains of gram-negative, nonmotile, aerobic bacteria obtained during iced storage of wild (Salmo trutta and Esox lucius) and farmed (Oncorhynchus mykiss) freshwater fish. Using diagnostic tables and computer-assisted identification, the isolates were Psychrobacter (64 strains), Acinetobacter (24 strains), Moraxella (6 strains), Chryseobacterium (5 strains), Myroides odoratus (2 strains), Flavobacterium (1 strain), Empedobacter (1 strain), and unidentified (3 strains). Overall similarities of all strains were determined for 108 characters by numerical analysis (simple matching coefficient of similarity [S] and clustering by unweighted pair group average linkage [UPGMA]). At the 77% similarity level, 92 strains formed nine major clusters (3 or more strains) and four small clusters (2 strains). Cluster 1 (25 isolates divided into two main subclusters) could be assigned to Psychrobacter phenylpyruvicus, clusters 2 and 3 (26 isolates) were designated as Psychrobacter immobilis, and clusters 4 (3 isolates) and 7 (4 isolates) were identified as Psychrobacter urativorans and Psychrobacter spp., respectively. Clusters 5 (five isolates), 6 (three isolates), and 9 (five isolates) were labeled as Acinetobacter spp., Acinetobacter johnsonii, and Acinetobacter lwoffii, respectively. Cluster 8 (12 isolates), with a high resemblance to Thornley's phenon 4 (a heterogeneous group of bacteria isolated from poultry and related to Acinetobacter), remained unnamed. The restriction pattern was identical for strains grouped into clusters 2 and 3 (P. immobilis) but was different for the remaining Psychrobacter isolates. A large proportion of isolates belonging to the family Moraxellaceae were closely related. Psychrobacters and A. johnsonii were present in freshly caught fish and river water. In the latter stages of storage, P. phenylpyruvicus and acinetobacters tended to decrease, whereas P. immobilis increased.
Topics: Animals; Bacterial Typing Techniques; Cold Temperature; DNA, Ribosomal; Esocidae; Fishes; Food Handling; Fresh Water; Gram-Negative Aerobic Bacteria; Numerical Analysis, Computer-Assisted; Oncorhynchus mykiss; Phenotype; RNA, Ribosomal, 16S; Restriction Mapping; Trout
PubMed: 10716558
DOI: 10.4315/0362-028x-63.3.315 -
International Journal of Systematic and... Nov 2003A facultatively psychrophilic bacterium, strain MD17(T), which hydrolyses lipids at 5 degrees C, was isolated from the Monbetsu coast of the Okhotsk Sea in Hokkaido,...
A facultatively psychrophilic bacterium, strain MD17(T), which hydrolyses lipids at 5 degrees C, was isolated from the Monbetsu coast of the Okhotsk Sea in Hokkaido, Japan, when ice carried by the cold current came to the area. The isolate is an aerobic, non-motile coccobacillus that reduces nitrate to nitrite and hydrolyses Tweens 20, 40, 60 and 80, but not gelatin, DNA or alginic acid. The isolate grows at 0 degrees C, but not at temperatures higher than 36 degrees C; its optimum growth temperature is 25 degrees C. It grows in the presence of 0-10 % NaCl. Its major isoprenoid quinone is ubiquinone-8 (Q-8) and its DNA G+C content is 46.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MD17(T) is closely related to Psychrobacter glacincola DSM 12194(T) (99.0 % similarity) and Psychrobacter immobilis DSM 7229(T) (98.7 % similarity). DNA-DNA hybridization revealed 45.9 % relatedness between strain MD17(T) and P. immobilis ATCC 43116(T) and 33.4 % between strain MD17(T) and P. glacincola ATCC 700754(T). Based on physiological and biochemical characteristics, phylogenetic position (as determined by 16S rRNA gene sequence analysis) and DNA-DNA relatedness, it is concluded that the isolate should be designated as a novel species, for which the name Psychrobacter okhotskensis sp. nov. is proposed. The type strain is MD17(T) (=NCIMB 13931(T)=JCM 11840(T)).
Topics: Base Composition; Base Sequence; DNA, Bacterial; Japan; Molecular Sequence Data; Moraxellaceae; Phylogeny; Seawater; Temperature
PubMed: 14657134
DOI: 10.1099/ijs.0.02686-0 -
International Journal of Food... 1992Of 126 samples of fresh and spoiled meat and dairy products, 40% were positive for the presence of Moraxella-like bacteria and 64% of Acinetobacter; 279 and 466 strains,...
Of 126 samples of fresh and spoiled meat and dairy products, 40% were positive for the presence of Moraxella-like bacteria and 64% of Acinetobacter; 279 and 466 strains, respectively, were isolated and a part of these were tested by biochemical methods and DNA transformation assays. In some cases, the Moraxellaceae in the samples examined reached considerable quantitative levels, but their percentage in the microflora was generally low. Moraxella-like bacteria were predominant in fresh meat, Acinetobacter in spoiled meat and milk. Most acinetobacters belonged to biotype lwoffii (sensu lato) and all 90 strains tested were positive for DNA transformation with an auxotrophic Acinetobacter. Moraxella-like bacteria were identified as Psychrobacter immobilis in 96% of 103 transformation assays. Moraxellaceae show lipolytic activity but they are considered of low incidence in food spoilage. Only 3.7% of acinetobacters from dairy sources was able to produce ropy milk. Unlike strains from clinical isolates, psychrobacters and acinetobacters isolated from food often do not grow at 37 degrees C.
Topics: Acinetobacter; Animals; Bacterial Typing Techniques; Cheese; Culture Media; Food Microbiology; Meat; Milk; Neisseriaceae; Oxidoreductases; Phenotype; Transformation, Bacterial
PubMed: 1622760
DOI: 10.1016/0168-1605(92)90136-q -
Systematic and Applied Microbiology Apr 2001An Antarctic marine bacterium (strain 116) excreting an extracellular cold-adapted metalloprotease was subjected to a detailed polyphasic taxonomic investigation. Strain...
Psychrobacter proteolyticus sp. nov., a psychrotrophic, halotolerant bacterium isolated from the Antarctic krill Euphausia superba Dana, excreting a cold-adapted metalloprotease.
An Antarctic marine bacterium (strain 116) excreting an extracellular cold-adapted metalloprotease was subjected to a detailed polyphasic taxonomic investigation. Strain 116 was previously isolated from the stomach of a specimen of the Antarctic krill Euphasia superba Dana and tentatively characterized as Sphingomonas paucimobilis 116. The 16S rDNA sequence analysis showed that the strain is in fact related to species of the genus Psychrobacter, next to Psychrobacter glacincola (97.4% similarity). Sequence similarities between strain 116 and other Psychrobacter species ranged from 96.9% (with P. urativorans) to 95.4% (with P. immobilis). Key phenotypic characteristics as well as chemotaxonomic features of the bacterium were congruent with the description of the genus Psychrobacter i.e. cells were strictly aerobic, strongly oxidase-positive, psychrotrophic, halotolerant, gram-negative non-motile coccobacilli, with ubiquinone-8 as the main respiratory lipoquinone and 18:1 cis 9, 16:1 cis and 17:1 (omega8c being the predominant cellular fatty acids. The G+C content of the DNA was 43.6 mol%. DNA-DNA hybridization studies showed that the relatedness between strain 116 and Psychrobacter glacinola is only 62.2%. Further differences were apparent in whole-cell SDS-PAGE protein pattern, cellular fatty acid profile and in a number of physiological and biochemical characteristics as well as in enzymatic activities. Tolerance to 5% bile salts, nitrate reduction, citrate utilization, acid production from carbohydrates, alkaline phosphatase, acid phosphatase, C4 esterase, C14 lipase and valine arylamidase were found to differentiate strain 116 from Psychrobacter glacincola. On the basis of this phenotypic and molecular evidences, strain 116, previously known as Sphingomonas paucimobilis 116, was recognized as a new species of the genus Psychrobacter for which the name Psychrobacter proteolyticus is proposed. Strain 116 has been deposited in the Collection de l'Institut Pasteur, France, as CIP106830T and in the Deutsche Sammlung von Mikroorganismen and Zellkulturen, as DSM13887.
Topics: Adaptation, Biological; Animals; Antarctic Regions; Bacterial Proteins; Bacterial Typing Techniques; Cold Temperature; Crustacea; DNA, Ribosomal; Drug Resistance, Microbial; Fatty Acids; Gammaproteobacteria; Gram-Negative Aerobic Rods and Cocci; Metalloendopeptidases; Molecular Sequence Data; RNA, Ribosomal, 16S; Salts
PubMed: 11403398
DOI: 10.1078/0723-2020-00006 -
Food Research International (Ottawa,... Jun 2024The microbiome of surfaces along the beef processing chain represents a critical nexus where microbial ecosystems play a pivotal role in meat quality and safety of end...
The microbiome of surfaces along the beef processing chain represents a critical nexus where microbial ecosystems play a pivotal role in meat quality and safety of end products. This study offers a comprehensive analysis of the microbiome along beef processing using whole metagenomics with a particular focus on antimicrobial resistance and virulence-associated genes distribution. Our findings highlighted that microbial communities change dynamically in the different steps along beef processing chain, influenced by the specific conditions of each micro-environment. Brochothrix thermosphacta, Carnobacterium maltaromaticum, Pseudomonas fragi, Psychrobacter cryohalolentis and Psychrobacter immobilis were identified as the key species that characterize beef processing environments. Carcass samples and slaughterhouse surfaces exhibited a high abundance of antibiotic resistance genes (ARGs), mainly belonging to aminoglycosides, β-lactams, amphenicols, sulfonamides and tetracyclines antibiotic classes, also localized on mobile elements, suggesting the possibility to be transmitted to human pathogens. We also evaluated how the initial microbial contamination of raw beef changes in response to storage conditions, showing different species prevailing according to the type of packaging employed. We identified several genes leading to the production of spoilage-associated compounds, and highlighted the different genomic potential selected by the storage conditions. Our results suggested that surfaces in beef processing environments represent a hotspot for beef contamination and evidenced that mapping the resident microbiome in these environments may help in reducing meat microbial contamination, increasing shelf-life, and finally contributing to food waste restraint.
Topics: Microbiota; Red Meat; Animals; Cattle; Food Microbiology; Food Handling; Bacteria; Metagenomics; Drug Resistance, Bacterial; Abattoirs; Anti-Bacterial Agents; Food Contamination; Drug Resistance, Microbial; Food Packaging
PubMed: 38729711
DOI: 10.1016/j.foodres.2024.114318 -
The Journal of Applied Bacteriology Jul 1988A numerical taxonomic study using 155 unit characters was performed on 63 strains of Gram-negative non-motile non-fermentative bacteria isolated from proteinaceous...
A numerical taxonomic study using 155 unit characters was performed on 63 strains of Gram-negative non-motile non-fermentative bacteria isolated from proteinaceous foods. Similar bacteria from other sources and several Pseudomonas strains from meat were included for reference purposes. Three clusters were observed at 76% S which contained all the food strains. Cluster 1 was composed entirely of Acinetobacter strains including 17 isolated from foods that were provisionally identified with Acinetobacter johnsonii. Cluster 2 contained 22 strains identified as Psychrobacter immobilis, of which 20 were from food. Cluster 3 contained all the Pseudomonas reference strains and 26 non-motile strains isolated from meat. These were shown to be non-motile variants of Pseudomonas fragi. A simple identification scheme, based on five tests, is presented for the distinction of the three types of bacteria.
Topics: Acinetobacter; Animals; Cattle; Fishes; Food Microbiology; Gram-Negative Bacteria; Meat; Poultry; Pseudomonas; Sheep; Swine
PubMed: 3209519
DOI: 10.1111/j.1365-2672.1988.tb04311.x