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A. Von Holy - One of the best experts on this subject based on the ideXlab platform.
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numerical taxonomy and identification of lactic acid bacteria from spoiled vacuum packaged vienna sausages
Journal of Applied Microbiology, 1994Co-Authors: Gary A. Dykes, T J Britz, A. Von HolyAbstract:Sixty-one lactic acid bacteria from spoiled vacuum-packaged vienna sausages and 15 reference strains were tested for 72 phenotypic characteristics. An identification key and a computer data base, both specific for lactic acid bacteria from meat sources, were used for identification and the results were compared. There was a high correlation (86.9%) between the two procedures in the identification of strains to genus level. However, only a 54.8% correlation was obtained in identifying strains to the species level. With numerical taxonomy (Ssm matching coefficient with average linkage clustering) 60 strains were recovered in six clusters at the 89% similarity level. While most Leuconostoc strains clustered separately from the Lactobacillus strains, the identity of many Leuconostocs was not clarified. The presence of a heterogeneous cluster containing typical and ‘atypical’ strains of the Lactobacillus sake/curvatus group and a separate homogeneous Lact. curvatus cluster was noted. Closer examination of the data suggested that the ‘atypical’ lactobacilli were all strains of Lact. sake.
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Identification of Leuconostoc species associated with the spoilage of vacuum-packaged Vienna sausages by DNA-DNA hybridization
Food Microbiology, 1994Co-Authors: Gary A. Dykes, T.e. Cloete, A. Von HolyAbstract:Abstract Approximately 36% of predominant microbiological spoilage populations from vacuum-packaged Vienna sausages consist of Leuconostocs which are difficult to identify phenotypically. Seven Leuconostocs selected on a pro-rata basis as representatives of three phenotypically different groups from this environment were identified by DNA-DNA hybridization as Leuconostoc mesenteroides subsp. mesenteroides (3), Leuconostoc gelidum (1) and Leuconostoc paramesenteroides (3). The presence of high proportions of Leuconostoc paramesenteroides and absence of Leuconostoc carnosum in this spoilage association was noteworthy. DNA-DNA hybridization represented a reliable identification method for meat spoilage Leuconostocs.
Gary A. Dykes - One of the best experts on this subject based on the ideXlab platform.
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numerical taxonomy and identification of lactic acid bacteria from spoiled vacuum packaged vienna sausages
Journal of Applied Microbiology, 1994Co-Authors: Gary A. Dykes, T J Britz, A. Von HolyAbstract:Sixty-one lactic acid bacteria from spoiled vacuum-packaged vienna sausages and 15 reference strains were tested for 72 phenotypic characteristics. An identification key and a computer data base, both specific for lactic acid bacteria from meat sources, were used for identification and the results were compared. There was a high correlation (86.9%) between the two procedures in the identification of strains to genus level. However, only a 54.8% correlation was obtained in identifying strains to the species level. With numerical taxonomy (Ssm matching coefficient with average linkage clustering) 60 strains were recovered in six clusters at the 89% similarity level. While most Leuconostoc strains clustered separately from the Lactobacillus strains, the identity of many Leuconostocs was not clarified. The presence of a heterogeneous cluster containing typical and ‘atypical’ strains of the Lactobacillus sake/curvatus group and a separate homogeneous Lact. curvatus cluster was noted. Closer examination of the data suggested that the ‘atypical’ lactobacilli were all strains of Lact. sake.
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Identification of Leuconostoc species associated with the spoilage of vacuum-packaged Vienna sausages by DNA-DNA hybridization
Food Microbiology, 1994Co-Authors: Gary A. Dykes, T.e. Cloete, A. Von HolyAbstract:Abstract Approximately 36% of predominant microbiological spoilage populations from vacuum-packaged Vienna sausages consist of Leuconostocs which are difficult to identify phenotypically. Seven Leuconostocs selected on a pro-rata basis as representatives of three phenotypically different groups from this environment were identified by DNA-DNA hybridization as Leuconostoc mesenteroides subsp. mesenteroides (3), Leuconostoc gelidum (1) and Leuconostoc paramesenteroides (3). The presence of high proportions of Leuconostoc paramesenteroides and absence of Leuconostoc carnosum in this spoilage association was noteworthy. DNA-DNA hybridization represented a reliable identification method for meat spoilage Leuconostocs.
Leon M. T. Dicks - One of the best experts on this subject based on the ideXlab platform.
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proposal to reclassify Leuconostoc oenos as oenococcus oeni corrig gen nov comb nov
International Journal of Systematic and Evolutionary Microbiology, 1995Co-Authors: Leon M. T. Dicks, Franco Dellaglio, M.d. CollinsAbstract:Wine strains belonging to the genus Leuconostoc were classified as Leuconostoc oenos by Garvie in 1967, and this name was confirmed on the Approved Lists of Bacterial Names in 1980. L. oenos is distinguished from other Leuconostoc spp. by its growth in acidic media, by its requirement for a growth factor in tomato juice, and by a number of carbohydrate fermentation characteristics. In addition, the results of a total soluble cell protein analysis, an electrophoretic analysis of NAD-dependent d-(—)-lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and alcohol dehydrogenase, and an analysis of cross-reactivity with anti-glucose-6-phosphate dehydrogenase and anti-NAD-dependent d-(—)-lactate dehydrogenase performed with other Leuconostoc spp. clearly indicated that L. oenos should be distinguished from the other Leuconostoc species. Phylogenetic studies, in particular 16S and 23S rRNA sequencing studies, have revealed that L. oenos represents a distinct subline that is separate from other Leuconostoc spp. and lactic acid bacteria. In view of the phenotypic and phylogenetic distinctiveness of L. oenos, we propose that this species should be assigned to a new genus as Oenococcus oeni [corrig.] gen. nov., comb. nov. The type strain of O. oeni is NCDO 1674 (= ATCC 23179).
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Identification of Leuconostoc oenos from South African fortified wines by numerical analysis of total soluble cell protein patterns and DNA‐DNA hybridizations
Journal of Applied Bacteriology, 1995Co-Authors: Leon M. T. Dicks, P. A. Loubser, O.p.h. AugustynAbstract:Eight ethanol-tolerant (17% v/v) strains of Leuconostoc were isolated from South African fortified wines which underwent spoilage in the bottle. The levels of genotypic relatedness of these strains to Leuconostoc oenos, Leuconostoc lactis, Leuconostoc argentinum, Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc mesenteroides subsp. dextranicum and Leuconostoc paramesenteroides (recently reclassified as Weissella paramesenteroides) were determined by performing numerical analysis of total soluble cell protein patterns and DNA-DNA hybridizations. The fortified wine strains grouped at r ≥ 0.90 into one cluster with the reference strains of Leuc. oenos and shared a DNA homology of 82-95% with the type strains of Leuc. oenos (NCFB 1674 T ). The fortified wine strains were genotypically unrelated to the non-acidophilic Leuconostoc spp.
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Relatedness of Leuconostoc species of the Leuconostoc sensu stricto Line of Descent, Leuconostoc oenos and Weissella paramesenteroides Revealed by Numerical Analysis of Total Soluble Cell Protein Patterns
Systematic and Applied Microbiology, 1995Co-Authors: Leon M. T. DicksAbstract:Summary The levels of phenotypic relatedness among Leuconostoc mesenteroides subsp. mesenteroides (six strains), Leuconostoc mesenteroides subsp. dextranicum (four strains), Leuconostoc mesenteroides subsp. cremoris (two strains), Leuconostoc pseudomesenteroides (three strains), Leuconostoc lactis (two strains), Leuconostoc argentinum (three strains), Leuconostoc citreum (two strains), Leuconostoc carnosum, Leuconostoc gelidum and Leuconostoc fallax (one strain of each), Leuconostoc oenos (seven strains), and Weissella paramesenteroides (two strains) were determined by numerical analysis of total soluble cell protein patterns. L. mesenteroides and the other species of the Leuconostoc sensu stricto line of descent grouped into separate well defined clusters at r ≥ 0.80, which linked at a level of r = 0.66. L. oenos clustered at r ≥ 0.81 and grouped with the Leuconostoc sensu stricto spp. at r = 0.62. W. paramesenteroides clustered with the Leuconostocs at r = 0.60. These groupings corresponded well with DNA similarity values recorded among the species.
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Lactic Acid Bacteria - The genus Leuconostoc
The Genera of Lactic Acid Bacteria, 1995Co-Authors: Franco Dellaglio, Leon M. T. Dicks, Sandra TorrianiAbstract:The genus Leuconostoc is phenotypically related to Lactobacillus and Pediococcus (Stackebrandt et al., 1983; Stackebrandt and Teuber, 1988) and share many features with the heterofermentative lactobacilli. In a recent comparative study of the 16S rRNA sequences (Yang and Woese, 1989), it was shown that the Leuconostocs form a natural phylogenetic group with Lb. confusus, Lb. halotolerans, Lb. handled, Lb. minor, and Lb. viridescens.
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Leuconostoc argentinum sp. nov., isolated from Argentine raw milk
International Journal of Systematic Bacteriology, 1993Co-Authors: Leon M. T. Dicks, L. Fantuzzi, M. Du Toit, F. C. Gonzalez, Franco DellaglioAbstract:The levels of genotypic relatedness among seven strains of Leuconostoc spp. isolated from Argentine raw milk, Leuconostoc lactis DSM 20202T (T = type strain) and DSM 20198, Leuconostoc mesenteroides subsp. mesenteroides NCDO 523T, Leuconostoc mesenteroides subsp. dextranicum NCDO 529T, and Leuconostoc paramesenteroides DSM 20288T were determined by performing a numerical analysis of total soluble cell protein patterns and DNA-DNA hybridization data. The Argentine raw milk strains formed a tight genotypic cluster at an r value of ≥0.85 and exhibited low levels of DNA homology with the other species included in this study. These strains represent a new species within the group of Leuconostocs isolated from milk or dairy products. The name Leuconostoc argentinum sp. nov. is proposed; the type strain is strain LL76.
Marie-christine Montel - One of the best experts on this subject based on the ideXlab platform.
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changes in the microbial composition of raw milk induced by thermization treatments applied prior to traditional greek hard cheese processing
Journal of Food Protection, 2009Co-Authors: John Samelis, Alexandra Lianou, Athanasia Kakouri, Celine Delbes, Irena Rogelj, Bojana Bogovicmatijasic, Marie-christine MontelAbstract:The microbiological quality, safety, and composition of mixtures of ewe's and goat's milk (90:10) used for cheesemaking were evaluated before and after thermization at 60 and 67°C for 30 s. Such mild thermal treatments are commonly applied to reduce natural contaminants of raw milk before processing for traditional hard Greek cheeses. Raw milk samples had an average total bacterial count of 7.3 log CFU/ml; most of these bacteria were lactic acid bacteria (LAB) and pseudomonads. The LAB flora of raw milk was dominated by enterococci (40.8%), followed by lactococci (20.4%), Leuconostocs (18.4%), and mesophilic lactobacilli (10.2%). Enterococcus faecalis (30.1%) and Enterococcus faecium (13.7%) were the most common LAB isolates, followed by Enterococcus durans, Lactococcus lactis subsp. lactis, Lactobacillus plantarum, and Leuconostoc lactis. Thermization at 60°C for 30 s was effective for reducing raw milk contamination by enterobacteria (5.1 log CFU/ml), coagulase-positive staphylococci (3.3 log CFU/ml), a...
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Changes in the microbial composition of raw milk induced by thermization treatments applied prior to traditional greek hard cheese processing
Journal of Food Protection, 2009Co-Authors: John Samelis, Alexandra Lianou, Athanasia Kakouri, Celine Delbes, Irena Rogelj, Bojana Bogovic-matijasic, Marie-christine MontelAbstract:The microbiological quality, safety, and composition of mixtures of ewe's and goat's milk (90: 10) used for cheesemaking were evaluated before and after thermization at 60 and 67 degrees C for 30 s. Such mild thermal treatments are commonly applied to reduce natural contaminants of raw milk before processing for traditional hard Greek cheeses. Raw milk samples had an average total bacterial count of 7.3 log CFU/ml; most of these bacteria were lactic acid bacteria (LAB) and pseudomonads. The LAB flora of raw milk was dominated by enterococci (40.8%), followed by lactococci (20.4%), Leuconostocs (18.4%), and mesophilic lactobacilli (10.2%). Enterococcus faecalis (30.1%) and Enterococcus faecium (13.7%) were the most common LAB isolates, followed by Enterococcus durons, Lactococcus lactis subsp. lactis, Lactobacillus plantarum, and Leuconostoc lactis. Thermization at 60 degrees C for 30 s was effective for reducing raw milk contamination by enterobacteria (5.1 log CFU/ml), coagulase-positive staphylococci (3.3 log CFU/ml), and Listeria (present in 25-ml samples) to safe levels, but it also reduced mesophilic lactococci, Leuconostocs, lactobacilli, and selected enterococci (72.0%) in thermized milk. Thermization at 67 degrees C for 30 s had a major inactivation effect on all bacterial groups. Two nisin-producing L. lactis subsp. lactis strains (M78 and M104) were isolated from raw milk, but neither nisin-producing nor other bacteriocin-producing LAB strains were isolated from thermized milk. Thus, thermization treatments control harmful bacteria but also may have a negative impact on milk quality by reducing desirable LAB and the biodiversity of raw milk bacteria overall, inactivating potentially protective LAB strains and enhancing the ability of potentially pathogenic enterococci to grow in fresh cheese curds
Charles Diviès - One of the best experts on this subject based on the ideXlab platform.
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Métabolisme sucre-citrate chez Leuconostoc mesenteroides
Le Lait, 2001Co-Authors: Gérald Bourel, Samia Henini, Kamel Krantar, Mona Oraby, Charles Diviès, Dominique GarmynAbstract:Sugar citrate cometabolism in Leuconostoc mesenteroides. Bacteria from the genus Leuconostoc play roles in the dairy industry. The most important functions of this bacteria are their ability to produce CO$_2$ and flavour compounds through lactose heterofermentation and citrate utilization. Although the biotechnological role of the citrate metabolism is very important and widely appreciated, little is known about the genetic properties of Leuconostoc spp. In our laboratory, we cloned the genes responsible for citrate metabolism (clyR mae citCDEFGOP cluster), for D-lactate dehydrogenase (ldhD) and for phosphotransacetylase (pta). In addition we have planned to construct new vectors and we have tried to improve a method to introduce recombinant DNA molecules into Leuconostoc as well. Characterization of the plasmid involved in this study is still in progress. The nucleotide sequence analysis of p22R revealed the presence of C5 cytosine methylase gene typical of type II restriction/modification system. The low transformation efficiency of some strains of Leuconostoc may be due to the presence of that plasmid. The construction of the defective strain for restriction activity could be very useful to genetic manipulations of Leuconostoc in the future.
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Research letterKinetics of citrate uptake in growing cells of Leuconostoc spp.
FEMS Microbiology Letters, 1996Co-Authors: Talal Belguendouz, Rémy Cachon, Charles DivièsAbstract:Citrate uptake was studied in growing cells of Leuconostoc mesenteroides subsp. mesenteroides. A Michaelis-Menten pattern with the dianionic form of citrate as the limiting substrate has been proposed. It was validated for different fermentations varying the initial citrate concentrations and the pH medium. This latter did not modify the rate of the process which was clearly confirmed using experiments with resting cells. The model was used to compare the kinetics of citrate consumption between several strains of Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc mesenteroides subsp. cremoris and Leuconostoc lactis.
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Kinetics of citrate uptake in growing cells of Leuconostoc spp.
FEMS Microbiology Letters, 1996Co-Authors: Talal Belguendouz, Rémy Cachon, Charles DivièsAbstract:Citrate uptake was studied in growing cells of Leuconostoc mesenteroides subsp. mesenteroides. A Michaelis-Menten pattern with the dianionic form of citrate as the limiting substrate has been proposed. It was validated for different fermentations varying the initial citrate concentrations and the pH medium. This latter did not modify the rate of the process which was clearly confirmed using experiments with resting cells. The model was used to compare the kinetics of citrate consumption between several strains of Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc mesenteroides subsp. cremoris and Leuconostoc lactis.
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Principal characteristics of β-galactosidase from Leuconostoc spp.
International Dairy Journal, 1995Co-Authors: D. Q. Huang, Hervé Prévost, Charles DivièsAbstract:Abstract β-Galactosidase (β-gal) and phospho-β-galactosidase (P-β-gal) from 33 strains belonging to different species of Leuconostoc have been investigated. P-β-gal was not detected, suggesting that the lactose transport system by translocation (PEPP-TS) is not functional in Leuconostoc . A great number of strains possess a high level of β-gal in the presence of glucose. Characterization of β-gal from several strains of Leuconostoc , in comparison with an industrial strain of S. thermophilus which was used as a reference, showed that the β-gal of Leuconostoc strains has a pH optimum at 7.2. The temperature optimum varied with the strain, ranging from 43 to 58 °C. The K m values of the enzymes on substrate o -nitrophenyl-β- d -galactopyranoside (ONPG) varied from 0.68 to 4.72 m m . The Leuconostoc β-gal had a lower affinity for lactose than that of S. thermophilus . Comparison of SDS-PAGE protein profiles for a Lac − mutant and its wild Lac + parental strain allowed the apparent molecular weight of β-gal to be estimated at approximately 80 000 for Leuc. mesenteroides subsp. mesenteroides , which is different from that of the β-gal of Leuconostoc lactis .
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Comparison of α-acetolactate synthase and α-acetolactate decarboxylase in Lactococcus spp. and Leuconostoc spp.
Biotechnology Letters, 1994Co-Authors: Christophe Monnet, V. Phalip, P. Schmitt, Charles DivièsAbstract:Cell-free extracts of Leuconostoc and Lactococcus species were tested for their alpha-acetolactate synthase and alpha-acetolactate decarboxylase activities. In Leuconostoc mesenteroides subsp. cremoris, Leuconostoc mesenteroides subsp. mesenteroides and Leuconostoc lactis, the Km of alpha-acetolactate synthase for pyruvate was close to 10 mM whereas it was 30 mM in Lactococcus lactis subsp. lactis biovar. diacetylactis. The Km of alpha-acetolactate decarboxylase for alpha-acetolactic acid was very low (0.3 mM) in Leuconostoc species in comparison to Lactococcus lactis subsp. lactis biovar. diacetylactis (60 mM). In the latter bacterium, alpha-acetolactate decarboxylase showed a sigmoidal dependance upon alpha-acetolactic acid and was activated by the three branched-chain amino acids: leucine, isoleucine and valine.