Chimia International Journal For Chemistry, May 31, 2002
ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laborator... more ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laboratory of Food Chemistry and Food Technology, the Laboratory of Food Process Engineering, the Laboratory of Food Microbiology, the Laboratory of Food Biotechnology, and the Laboratory of Human Nutrition. Six professors co-ordinate the teaching programme for the undergraduate course in Food Science and each has his own focussed research programme. In addition the Laboratory of Human Nutrition co-ordinates a one-year postgraduate diploma in Human Nutrition. The following review describes the teaching and research programmes, and selected projects.
ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laborator... more ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laboratory of Food Chemistry and Food Technology, the Laboratory of Food Process Engineering, the Laboratory of Food Microbiology, the Laboratory of Food Biotechnology, and the Laboratory of Human Nutrition. Six professors co-ordinate the teaching programme for the undergraduate course in Food Science and each has his own focussed research programme. In addition the Laboratory of Human Nutrition co-ordinates a one-year postgraduate diploma in Human Nutrition. The following review describes the teaching and research programmes, and selected projects.
We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens contain... more We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens containing the superoxide dismutase-encoding gene, sod. Previously, rubrerythrin from C. perfringens had been isolated and its gene (rbr) had been cloned (Y. Lehmann, L. Meile, and M. Teuber, J. Bacteriol. 178:7152-7158, 1996). Northern blot experiments revealed a length of approximately 800 bases for each transcript of rbr and sod of C. perfringens. Thus, rbr and sod each represent a monocistronic operon. Their transcription start points were located by primer extension analyses. sod transcription was shown to depend on the growth phase, and it reached a maximum during the transition from log phase to stationary phase. Neither sod nor rbr transcription was influenced by oxidative stress.
ABSTRACT Genetic modification of microorganisms has been applied to the production of food enzyme... more ABSTRACT Genetic modification of microorganisms has been applied to the production of food enzymes such as chymosin, and to the optimization of traditional microorganisms used in the fermentation of food such as baker's yeast and lactic acid bacteria. Chymosin produced with genetically modified Escherichia coli K12, Kluyveromyces lactis, and Aspergillus niger subsp. awamori has been accepted by some markets in about 20 countries and therefore entered the human food chain. However, genetically modified baker's yeast has it much harder achieving acceptance although it has been approved in the United Kingdom. Genetic engineering of food systems is not a matter of the inventing scientists and industries only, it is as much a matter of acceptance by the consumer and the general public. It is the scope of this review to describe the biotechnology of the chymosin and baker's yeast systems, and to outline some other systems such as the lactic acid bacteria. The technical description is supplemented with information on safety assessment, regulation, and labeling, as well as the theory and practice of risk perception and acceptance of such products by the general public.
Phosphoenolpyruvate-dependent phosphorylation of methyl-a-D-glucopyranoside in Salmonella typhimu... more Phosphoenolpyruvate-dependent phosphorylation of methyl-a-D-glucopyranoside in Salmonella typhimurium is increased by the membrane active polypeptide antibiotic polymyxin B whereas active transport ability is abolished.
Amino groups of cell envelope proteins, lipids, and lipopolysaccharides cannot be labeled in inta... more Amino groups of cell envelope proteins, lipids, and lipopolysaccharides cannot be labeled in intact cells of Salmonella typhimurium G 30 by using 5-diznethylaminonaphthalene-l-sulfonylchloride incorporated in lecithin-cholesterol vesicles. However, application of membrane-interacting agents like tris(hydroxymethyl)aminomethane (Tris)-hydrochloride, ethylenediaminetetraacetate (Na salt) (EDTA), divalent cations, and sublethal doses of the cationic antibacterial agents polymyxin B and chlorhexidine induced specific fluorescent labeling of envelope proteins and lipids but not of cytoplasmic compounds, with the exception of a soluble protein with a molecular weight of 46,000 in sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Treatment with Tris-hydrochloride buffer produced labeling of the heat-modifiable protein B/B+ and of proteins with molecular weights of 26,000, 22,000, and below 17,000. A combination of Trishydrochloride and EDTA induced additional dansylation of the major protein A and of proteins of molecular weights 80,000, 60,000, and 44,000. Polymyxin B and chlorhexidine caused similar labeling patterns. In every case, except with divalent cation treatment, protein B/B+ was the most prominently labeled species. Phosphatidylethanolamine was dansylated up to 30%. Lipopolysaccharide was not reactive under any condition or treatment. In addition, the peptidoglycan-bound lipoprotein did not react with dansylchloride in either intact or Tris-hydrochloride-treated cells. The results are discussed with regard to a possible localization of labeled and unlabeled compounds of the cell envelope on the basis of a model placing cell envelope amino groups into ion-ion interactions with anionic components of other envelope compounds like phosphate and carboxyl groups.
ABSTRACT In order to evaluate the potential of horizontal and vertical gene transfer in S. thermo... more ABSTRACT In order to evaluate the potential of horizontal and vertical gene transfer in S. thermophilus isolated from yogurt and yogurt starter cultures, 18 strains were mated in vitro with Lactococcus lactis subsp. lactis Bu2-60 harbouring plasmid pAMβ1 from Enterococcus faecalis. pAMβ1 was transferred into 8 strains with transfer frequencies per recipient ranging from 4 × 10-5 to 8 × 10-9. In intraspecific crosses between S. thermophilus strains, transfer of pAMβl was detected at transfer rates of 1 × 10-4 to 1 × 10-7, while retransfer of pAMβl into L. lactis subsp. lactis Bu2-60 always occurred at high frequencies (2 × 10-4 to 1 × 10-4). However, conjugal transfer of pAMβl among S. thermophilus strains was not detected in fermented milk. Two S. thermophilus strains could be transformed by electroporation with the lactococcal vector pNZ18 with low efficiency. A transfer of pNZ18 was not observed in S. thermophilus strains. Segregational stability of this heterologous DNA was studied during non-selective propagation in skim milk. Plasmid pNZ18 was stably maintained in more than 80% of the S. thermophilus cells after 144 generations at 42 °C, and was still present in more than 60% of the cells after 126 generations (growth at 37 °C) or 72 generations (growth at 32 °C). Growth temperature mediated an opposite effect on the stability of pAMβl in S. thermophilus in which no loss was detected after 84 generations at 37 °C, while a rapid loss occured at 42 °C. Upon associative growth with Lactobacillus delbrueckii subsp. bulgaricus, maintenance of pNZ18 was enhanced in S. thermophilus, while a minor decrease in stability was detected for pAMβ1.
Lactobacilli isolated from different food and feed samples such as raw milk, cheese, yoghurt, oli... more Lactobacilli isolated from different food and feed samples such as raw milk, cheese, yoghurt, olives, sour dough, as well as corn and grass silage, were screened for their antifungal activities. Out of 1,424 isolates tested, 82 were shown to be inhibitory to different yeasts (Candida spp. and Zygosaccharomyces bailii) and a Penicillium sp., which were previously isolated from spoiled yoghurt and fruits. Carbohydrate fermentation patterns suggested that a substantial portion, 25%, belonged to the Lactobacillus casei group, including L. casei, L. paracasei, and L. rhamnosus. The isolates SM20 (DSM14514), SM29 (DSM14515), and SM63 (DSM14516) were classified by PCR using species-specific primers to target the corresponding type strains (L. casei, L. paracasei, and L. rhamnosus) as controls. Further molecular typing methods such as randomly amplified polymorphic DNA, pulsed-field gel electrophoresis, and sequencing analysis of the 16S rRNA gene allowed classifying strains SM20, SM29, and...
We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens contain... more We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens containing the superoxide dismutase-encoding gene, sod. Previously, rubrerythrin from C. perfringens had been isolated and its gene (rbr) had been cloned (Y. Lehmann, L. Meile, and M. Teuber, J. Bacteriol. 178:7152-7158, 1996). Northern blot experiments revealed a length of approximately 800 bases for each transcript of rbr and sod of C. perfringens. Thus, rbr and sod each represent a monocistronic operon. Their transcription start points were located by primer extension analyses. sod transcription was shown to depend on the growth phase, and it reached a maximum during the transition from log phase to stationary phase. Neither sod nor rbr transcription was influenced by oxidative stress.
ABSTRACT Lactococci are coccoid Gram-positive, anaerobic bacteria which produce l(+)-lactic acid ... more ABSTRACT Lactococci are coccoid Gram-positive, anaerobic bacteria which produce l(+)-lactic acid from lactose in spontaneously fermented raw milk which is left at ambient temperatures around 20–30°C for 10–20 h. They are commonly called ‘mesophilic lactic streptococci’. It is tempting to suggest that the first isolation, identification and description of the chemical entity lactic acid by Carl Wilhelm Scheele from sour milk in Sweden in the year 1780, was actually l (+)-lactic acid produced by lactococci. The microbial nature of lactic fermentation was recognized in 1857 by Louis Pasteur. The first bacterial pure culture on earth, obtained and scientifically described by Joseph Lister (1873) was Lactococcus lactis, at that time called: ‘Bacterium lactis’. Admitting then that we had here to deal with only one bacterium, it presents such peculiarities both morphologically and physiologically as to justify us, I think, in regarding it a definite and recognizable species for which I venture to suggest the name Bacterium lactis. This I do with diffidence, believing that up to this time no bacterium has been defined by reliable characters. Whether this is the only bacterium that can occasion the lactic acid fermentation, I am not prepared to say.
... MicrococcuslArthrobacter and MicrobacteriumlAureobacterium Used in Dairy Starter Cultures BEA... more ... MicrococcuslArthrobacter and MicrobacteriumlAureobacterium Used in Dairy Starter Cultures BEAT KOLLOFFEL, SANDRA BURRI, LEO MElLE, and ... SCHUBERT, K., LUDWIG, W., SPRINGER, N., KROPPENSTEDT, RM, ACCOLAS, JP, FIEDLER, F.: Two coryneform bacteria ...
We purified a bacteriocin from the cell-free supernatant of Propionibacterium jensenii DF1 isolat... more We purified a bacteriocin from the cell-free supernatant of Propionibacterium jensenii DF1 isolated from Swiss raw milk, and named it propionicin SM1. The heat-stable protein was strongly bactericidal against P. jensenii DSM20274. On the basis of the N-terminal amino acid sequence of the purified protein, a degenerate oligonucleotide probe was designed to locate and clone the corresponding gene of P. jensenii DF1. It hybridized exclusively with the DF1l-resident plasmid pLME106, but not with chromosomal DNA. Sequencing of the 6.9-kb plasmid revealed the targeted amino acid sequence within an open reading frame (ORF4) of 207 amino acids (molecular mass, 22,865 Da). The corresponding gene was named ppnA. It encodes the prepeptide PpnA that is processed to the mature protein (19,942 Da) propionicin SM1. No sequence homology is detectable with known proteins. However, the proposed leader peptide sequence containing 27 amino acids has typical signal peptide features and shows good homology to the leader peptide of Usp45, a protein excreted from Lactococcus lactis (VAN ASSELDONK et al., 1993). Plasmid pLME106 contains at least 9 ORFs, some exhibiting significant homologies to plasmid-encoded functions from other bacteria. The highest identity values were found for ORF1 with the theta replicase (acc. no. U39878) of Brevibacterium linens (58.8%) and ORF6 with the recombinase/invertase (acc. no. AF060871) found in Rhodococcus rhodochrous (46.4%).
Two staphylococcal strains, RP29 T and RP33, were isolated from the main microflora of a surface ... more Two staphylococcal strains, RP29 T and RP33, were isolated from the main microflora of a surface ripened Swiss mountain cheese made from raw milk. These two strains were differentiated from the most closely related species Staphylococcus equorum on the basis of DNA-DNA hybridisation and phenotypic characteristics and are proposed as Staphylococcus equorum subsp. linens subsp. nov. They could be distinguished phenotypically from S. equorum by their sensitivity to all 14 tested antibiotics, especially to novobiocin, their incapability to ferment α-D-lactose, maltose, sucrose, D-trehalose, D-xylose, L-arabinose, salicin, D-ribose, D-raffinose, D-mannitol, and D-alanine. The GenBank accession numbers for the reference sequences of the 16S rDNA and the hsp60 gene used in this study are AF527483 and AF527484, respectively. 30 tons of a semi-hard Swiss cheese were produced with Staphylococcus equorum subsp. linens DSM 15097 T as starter culture component in addition to Debaryomyces hansenii, Geotrichum candidum, Brevibacterium linens, Corynebacterium casei for surface ripened cheeses. The products were sensorically and hygienically perfect. Therefore, Staphylococcus equorum subsp. linens DSM 15097 T can be proposed as starter culture component for surface ripened cheeses without any detected antibiotic resistances. The type strain of Staphylococcus equorum subsp. linens is DSM 15097 T (CIP 107656 T ).
Chimia International Journal For Chemistry, May 31, 2002
ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laborator... more ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laboratory of Food Chemistry and Food Technology, the Laboratory of Food Process Engineering, the Laboratory of Food Microbiology, the Laboratory of Food Biotechnology, and the Laboratory of Human Nutrition. Six professors co-ordinate the teaching programme for the undergraduate course in Food Science and each has his own focussed research programme. In addition the Laboratory of Human Nutrition co-ordinates a one-year postgraduate diploma in Human Nutrition. The following review describes the teaching and research programmes, and selected projects.
ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laborator... more ABSTRACT The Institute of Food Science and Nutrition consists of five laboratories: the Laboratory of Food Chemistry and Food Technology, the Laboratory of Food Process Engineering, the Laboratory of Food Microbiology, the Laboratory of Food Biotechnology, and the Laboratory of Human Nutrition. Six professors co-ordinate the teaching programme for the undergraduate course in Food Science and each has his own focussed research programme. In addition the Laboratory of Human Nutrition co-ordinates a one-year postgraduate diploma in Human Nutrition. The following review describes the teaching and research programmes, and selected projects.
We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens contain... more We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens containing the superoxide dismutase-encoding gene, sod. Previously, rubrerythrin from C. perfringens had been isolated and its gene (rbr) had been cloned (Y. Lehmann, L. Meile, and M. Teuber, J. Bacteriol. 178:7152-7158, 1996). Northern blot experiments revealed a length of approximately 800 bases for each transcript of rbr and sod of C. perfringens. Thus, rbr and sod each represent a monocistronic operon. Their transcription start points were located by primer extension analyses. sod transcription was shown to depend on the growth phase, and it reached a maximum during the transition from log phase to stationary phase. Neither sod nor rbr transcription was influenced by oxidative stress.
ABSTRACT Genetic modification of microorganisms has been applied to the production of food enzyme... more ABSTRACT Genetic modification of microorganisms has been applied to the production of food enzymes such as chymosin, and to the optimization of traditional microorganisms used in the fermentation of food such as baker's yeast and lactic acid bacteria. Chymosin produced with genetically modified Escherichia coli K12, Kluyveromyces lactis, and Aspergillus niger subsp. awamori has been accepted by some markets in about 20 countries and therefore entered the human food chain. However, genetically modified baker's yeast has it much harder achieving acceptance although it has been approved in the United Kingdom. Genetic engineering of food systems is not a matter of the inventing scientists and industries only, it is as much a matter of acceptance by the consumer and the general public. It is the scope of this review to describe the biotechnology of the chymosin and baker's yeast systems, and to outline some other systems such as the lactic acid bacteria. The technical description is supplemented with information on safety assessment, regulation, and labeling, as well as the theory and practice of risk perception and acceptance of such products by the general public.
Phosphoenolpyruvate-dependent phosphorylation of methyl-a-D-glucopyranoside in Salmonella typhimu... more Phosphoenolpyruvate-dependent phosphorylation of methyl-a-D-glucopyranoside in Salmonella typhimurium is increased by the membrane active polypeptide antibiotic polymyxin B whereas active transport ability is abolished.
Amino groups of cell envelope proteins, lipids, and lipopolysaccharides cannot be labeled in inta... more Amino groups of cell envelope proteins, lipids, and lipopolysaccharides cannot be labeled in intact cells of Salmonella typhimurium G 30 by using 5-diznethylaminonaphthalene-l-sulfonylchloride incorporated in lecithin-cholesterol vesicles. However, application of membrane-interacting agents like tris(hydroxymethyl)aminomethane (Tris)-hydrochloride, ethylenediaminetetraacetate (Na salt) (EDTA), divalent cations, and sublethal doses of the cationic antibacterial agents polymyxin B and chlorhexidine induced specific fluorescent labeling of envelope proteins and lipids but not of cytoplasmic compounds, with the exception of a soluble protein with a molecular weight of 46,000 in sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Treatment with Tris-hydrochloride buffer produced labeling of the heat-modifiable protein B/B+ and of proteins with molecular weights of 26,000, 22,000, and below 17,000. A combination of Trishydrochloride and EDTA induced additional dansylation of the major protein A and of proteins of molecular weights 80,000, 60,000, and 44,000. Polymyxin B and chlorhexidine caused similar labeling patterns. In every case, except with divalent cation treatment, protein B/B+ was the most prominently labeled species. Phosphatidylethanolamine was dansylated up to 30%. Lipopolysaccharide was not reactive under any condition or treatment. In addition, the peptidoglycan-bound lipoprotein did not react with dansylchloride in either intact or Tris-hydrochloride-treated cells. The results are discussed with regard to a possible localization of labeled and unlabeled compounds of the cell envelope on the basis of a model placing cell envelope amino groups into ion-ion interactions with anionic components of other envelope compounds like phosphate and carboxyl groups.
ABSTRACT In order to evaluate the potential of horizontal and vertical gene transfer in S. thermo... more ABSTRACT In order to evaluate the potential of horizontal and vertical gene transfer in S. thermophilus isolated from yogurt and yogurt starter cultures, 18 strains were mated in vitro with Lactococcus lactis subsp. lactis Bu2-60 harbouring plasmid pAMβ1 from Enterococcus faecalis. pAMβ1 was transferred into 8 strains with transfer frequencies per recipient ranging from 4 × 10-5 to 8 × 10-9. In intraspecific crosses between S. thermophilus strains, transfer of pAMβl was detected at transfer rates of 1 × 10-4 to 1 × 10-7, while retransfer of pAMβl into L. lactis subsp. lactis Bu2-60 always occurred at high frequencies (2 × 10-4 to 1 × 10-4). However, conjugal transfer of pAMβl among S. thermophilus strains was not detected in fermented milk. Two S. thermophilus strains could be transformed by electroporation with the lactococcal vector pNZ18 with low efficiency. A transfer of pNZ18 was not observed in S. thermophilus strains. Segregational stability of this heterologous DNA was studied during non-selective propagation in skim milk. Plasmid pNZ18 was stably maintained in more than 80% of the S. thermophilus cells after 144 generations at 42 °C, and was still present in more than 60% of the cells after 126 generations (growth at 37 °C) or 72 generations (growth at 32 °C). Growth temperature mediated an opposite effect on the stability of pAMβl in S. thermophilus in which no loss was detected after 84 generations at 37 °C, while a rapid loss occured at 42 °C. Upon associative growth with Lactobacillus delbrueckii subsp. bulgaricus, maintenance of pNZ18 was enhanced in S. thermophilus, while a minor decrease in stability was detected for pAMβ1.
Lactobacilli isolated from different food and feed samples such as raw milk, cheese, yoghurt, oli... more Lactobacilli isolated from different food and feed samples such as raw milk, cheese, yoghurt, olives, sour dough, as well as corn and grass silage, were screened for their antifungal activities. Out of 1,424 isolates tested, 82 were shown to be inhibitory to different yeasts (Candida spp. and Zygosaccharomyces bailii) and a Penicillium sp., which were previously isolated from spoiled yoghurt and fruits. Carbohydrate fermentation patterns suggested that a substantial portion, 25%, belonged to the Lactobacillus casei group, including L. casei, L. paracasei, and L. rhamnosus. The isolates SM20 (DSM14514), SM29 (DSM14515), and SM63 (DSM14516) were classified by PCR using species-specific primers to target the corresponding type strains (L. casei, L. paracasei, and L. rhamnosus) as controls. Further molecular typing methods such as randomly amplified polymorphic DNA, pulsed-field gel electrophoresis, and sequencing analysis of the 16S rRNA gene allowed classifying strains SM20, SM29, and...
We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens contain... more We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridium perfringens containing the superoxide dismutase-encoding gene, sod. Previously, rubrerythrin from C. perfringens had been isolated and its gene (rbr) had been cloned (Y. Lehmann, L. Meile, and M. Teuber, J. Bacteriol. 178:7152-7158, 1996). Northern blot experiments revealed a length of approximately 800 bases for each transcript of rbr and sod of C. perfringens. Thus, rbr and sod each represent a monocistronic operon. Their transcription start points were located by primer extension analyses. sod transcription was shown to depend on the growth phase, and it reached a maximum during the transition from log phase to stationary phase. Neither sod nor rbr transcription was influenced by oxidative stress.
ABSTRACT Lactococci are coccoid Gram-positive, anaerobic bacteria which produce l(+)-lactic acid ... more ABSTRACT Lactococci are coccoid Gram-positive, anaerobic bacteria which produce l(+)-lactic acid from lactose in spontaneously fermented raw milk which is left at ambient temperatures around 20–30°C for 10–20 h. They are commonly called ‘mesophilic lactic streptococci’. It is tempting to suggest that the first isolation, identification and description of the chemical entity lactic acid by Carl Wilhelm Scheele from sour milk in Sweden in the year 1780, was actually l (+)-lactic acid produced by lactococci. The microbial nature of lactic fermentation was recognized in 1857 by Louis Pasteur. The first bacterial pure culture on earth, obtained and scientifically described by Joseph Lister (1873) was Lactococcus lactis, at that time called: ‘Bacterium lactis’. Admitting then that we had here to deal with only one bacterium, it presents such peculiarities both morphologically and physiologically as to justify us, I think, in regarding it a definite and recognizable species for which I venture to suggest the name Bacterium lactis. This I do with diffidence, believing that up to this time no bacterium has been defined by reliable characters. Whether this is the only bacterium that can occasion the lactic acid fermentation, I am not prepared to say.
... MicrococcuslArthrobacter and MicrobacteriumlAureobacterium Used in Dairy Starter Cultures BEA... more ... MicrococcuslArthrobacter and MicrobacteriumlAureobacterium Used in Dairy Starter Cultures BEAT KOLLOFFEL, SANDRA BURRI, LEO MElLE, and ... SCHUBERT, K., LUDWIG, W., SPRINGER, N., KROPPENSTEDT, RM, ACCOLAS, JP, FIEDLER, F.: Two coryneform bacteria ...
We purified a bacteriocin from the cell-free supernatant of Propionibacterium jensenii DF1 isolat... more We purified a bacteriocin from the cell-free supernatant of Propionibacterium jensenii DF1 isolated from Swiss raw milk, and named it propionicin SM1. The heat-stable protein was strongly bactericidal against P. jensenii DSM20274. On the basis of the N-terminal amino acid sequence of the purified protein, a degenerate oligonucleotide probe was designed to locate and clone the corresponding gene of P. jensenii DF1. It hybridized exclusively with the DF1l-resident plasmid pLME106, but not with chromosomal DNA. Sequencing of the 6.9-kb plasmid revealed the targeted amino acid sequence within an open reading frame (ORF4) of 207 amino acids (molecular mass, 22,865 Da). The corresponding gene was named ppnA. It encodes the prepeptide PpnA that is processed to the mature protein (19,942 Da) propionicin SM1. No sequence homology is detectable with known proteins. However, the proposed leader peptide sequence containing 27 amino acids has typical signal peptide features and shows good homology to the leader peptide of Usp45, a protein excreted from Lactococcus lactis (VAN ASSELDONK et al., 1993). Plasmid pLME106 contains at least 9 ORFs, some exhibiting significant homologies to plasmid-encoded functions from other bacteria. The highest identity values were found for ORF1 with the theta replicase (acc. no. U39878) of Brevibacterium linens (58.8%) and ORF6 with the recombinase/invertase (acc. no. AF060871) found in Rhodococcus rhodochrous (46.4%).
Two staphylococcal strains, RP29 T and RP33, were isolated from the main microflora of a surface ... more Two staphylococcal strains, RP29 T and RP33, were isolated from the main microflora of a surface ripened Swiss mountain cheese made from raw milk. These two strains were differentiated from the most closely related species Staphylococcus equorum on the basis of DNA-DNA hybridisation and phenotypic characteristics and are proposed as Staphylococcus equorum subsp. linens subsp. nov. They could be distinguished phenotypically from S. equorum by their sensitivity to all 14 tested antibiotics, especially to novobiocin, their incapability to ferment α-D-lactose, maltose, sucrose, D-trehalose, D-xylose, L-arabinose, salicin, D-ribose, D-raffinose, D-mannitol, and D-alanine. The GenBank accession numbers for the reference sequences of the 16S rDNA and the hsp60 gene used in this study are AF527483 and AF527484, respectively. 30 tons of a semi-hard Swiss cheese were produced with Staphylococcus equorum subsp. linens DSM 15097 T as starter culture component in addition to Debaryomyces hansenii, Geotrichum candidum, Brevibacterium linens, Corynebacterium casei for surface ripened cheeses. The products were sensorically and hygienically perfect. Therefore, Staphylococcus equorum subsp. linens DSM 15097 T can be proposed as starter culture component for surface ripened cheeses without any detected antibiotic resistances. The type strain of Staphylococcus equorum subsp. linens is DSM 15097 T (CIP 107656 T ).
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