n-nitrosamine formation by cultures of several microorganisms.of 38 pure cultures of microorganisms tested, only one, pseudomonas stutzeri, was capable of forming dimethylnitrosamine from dimethylamine and nitrite during growth. resting cells of p. stutzeri, cryptococcus terreus, escherichia coli, and xanthomonas campestris formed dimethylnitrosamine, although no nitrosamine was found in growing cultures of the latter three organisms. no nitrosamine was produced by either growing cultures or resting-cell suspensions of pseudomonas fragi or proteus mirabili ...19767197
destruction of bacteria on fresh meat by hot water.strains of different bacterial genera; escherichia coli (7), salmonella serotypes (7), enteropathogenic e. coli o 157 (2), aeromonas hydrophila (4), yersinia enterocolytica (1), pseudomonas fragi (5), and listeria monocytogenes (5), inoculated onto the surface tissues of pieces of fresh beef were found to be susceptible to the lethal action of hot water. on average, more than 3 log10 (99.9%) of these organisms were destroyed when water at 80 degrees c was applied for 10 or 20 s. therefore, a hot ...19921468533
primary structures of the genes, faoa and faob, from pseudomonas fragi b-0771 which encode the two subunits of the hdt multienzyme complex involved in fatty acid beta-oxidation.three enzyme activities involved in fatty acid beta-oxidation, i.e., those of enoyl-coa hydratase, 3-hydroxyacyl-coa dehydrogenase, and 3-oxoacyl-coa thiolase, are exhibited by one multienzyme complex (hdt) composed of two molecules each of two peptides in pseudomonas fragi. using specific antisera against the two subunits of hdt, we isolated the genes encoding the subunits of hdt and designated them "faoa" (for the alpha-subunit) and "faob" (for the beta-subunit). their complete nucleotide sequ ...19921607366
the behavior of selected microorganisms during the manufacture of high moisture jack cheeses from ultrafiltered milk.whole milk was pasteurized and concentrated two times by ultrafiltration. starter cultures, lactococcus lactis ssp. cremoris and lactococcus lactis ssp. lactis, were propagated in either reconstituted skim milk, two times uf retentate, or uf permeate, or a direct vat system was used for the starter culture. the cheese milk was simultaneously inoculated with starter culture and pseudomonas fragi 4973, staphylococcus aureus 196e, and salmonella typhimurium var. hillfarm. control whole milk, uf con ...19911779045
bioluminescence assay for estimating the hydrophobic properties of bacteria as revealed by hydrophobic interaction chromatography.the luciferin-luciferase bioluminescence method was used to estimate the number of bacteria retained in neutral and amphiphilic gels and those in the eluate to determine the hydrophobic surface properties of bacteria by using hydrophobic interaction chromatography. good correlations were found between viable counts and atp content for escherichia coli, pseudomonas fragi, and listeria monocytogenes. atp determination was more rapid than viable counts for characterizing the relative hydrophobicity ...19911908207
purification of the multienzyme complex for fatty acid oxidation from pseudomonas fragi and reconstitution of the fatty acid oxidation system.the multienzyme complex for fatty acid oxidation was purified from pseudomonas fragi, which was grown on oleic acid as the sole carbon source. this complex exhibited enoyl-coa hydratase [ec], 3-hydroxyacyl-coa dehydrogenase [ec], 3-oxoacyl-coa thiolase [ec], cis-3,trans-2-enoyl-coa isomerase [ec], and 3-hydroxyacyl-coa epimerase [ec] activities. the molecular weight of the native complex was estimated to be 240,000. two types of subunits, with molecular ...19902361950
a numerical taxonomic study of non-motile non-fermentative gram-negative bacteria from foods.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 acineto ...19883209519
enzymatic transesterification with the lipase from pseudomonas fragi 22.39 b in a non-aqueous reaction system.the lipase from pseudomonas fragi 22.39 b catalyzed the transesterification in ester and alcohol mixtures without any other solvent. activated esters, such as vinyl and phenyl esters, were excellent acyl donors for the reaction, and the activity was enhanced by increasing the carbon number of the fatty acid fraction of the esters. primary alcohols were esterified faster than secondary ones in this reaction system, while tertiary alcohols such as alpha-terpineol did not react at all. the lipase e ...19883235444
[taxonomic study of pseudomonas fragi]. 19883412197
volatile compounds produced by meat pseudomonads and relate reference strains during growth on beef stored in air at chill temperatures.volatile compounds produced by 31 strains of pseudomonads and by reference strains of pseudomonas fragi and ps. fluorescens biotype 1 during growth on beef stored at 6 degrees c in air were analysed by gas chromatography-mass spectrometry of headspace gases. compounds of major sensory significance were ethyl and methyl esters of c2-c8 fatty acids and sulphur-containing compounds which included methane- and isopropanethiols and their related sulphides and thioesters but not hydrogen sulphide. est ...19873610888
sulfite, an elective agent in the microbiological and chemical changes occurring in uncooked comminuted meat products.the literature dealing with sulfite preservation of meat products is reviewed. discussion is centered on three aspects: (i) the elective action of sulfite, whereby its presence in meat products encourages the development of an association of gram-positive bacteria (brochothrix thermosphacta and homofermentative lactobacilli) and yeasts. unsulfited products tend to be dominated by pseudomonas fragi at chill, and enterobacteriaceae at ambient temperatures; (ii) the diminution of the preservative p ...19853902765
observations by electron microscopy on pig muscle inoculated and incubated with pseudomonas fragi.myofibrils from pig muscle inoculated and incubated with pseudomonas fragi showed an extremely disrupted appearance as compared to uninoculated controls. there was an almost complete absence of material in the h zone, marked disruption of the a band (probably myosin), and some loss of dense material from the z line. these changes indicated that marked proteolysis had occurred. bacteria observed in spoiled muscle tissue exhibited protrusions or blebs on the outer surface of the cell walls. the bl ...19714109490
identification of proteolytic pseudomonads isolated from raw milk.proteolytic pseudomonads isolated from raw milk were classified by numerical taxonomy. unweighted pair-group average-linkage cluster analysis was used to cluster 49 bacterial strains, of which 26 were pseudomonas species, as described in the bergey's manual of determinative bacteriology, based on 52 characters. the milk isolates resided in two clusters; one containing pseudomonas fluorescens and the other pseudomonas fragi. the isolates identified with pseudomonas fluorescens hydrolyzed milk pro ...19853930583
experimental studies on the formation of volatile nitrogen compounds induced by pseudomonas fragi in a synthetic medium with amino acids as source of nitrogen. 19724634720
experimental studies on the volatile nitrogen compounds produced by pseudomonas fragi in fish extracts. 19724673740
mixed carbon source utilization of meat-spoiling pseudomonas fragi 72 in relation to oxygen limitation and carbon dioxide inhibition.the growth of meat-spoiling pseudomonas fragi 72 was studied on a defined salt medium supplemented with l-aspartate, citrate, creatine, creatinine, d-glucose, l-glutamate, and l-lactate. the utilization of the different carbon sources was followed in batch and continuous culture and under the influence of oxygen limitation and carbon dioxide inhibition (50% co2 in air). under nonrestricted atmospheric conditions in batch culture, the organism showed a preference in the utilization of the carbon ...19853925882
identification of the volatile compounds produced in sterile fish muscle (sebastes melanops) by pseudomonas fragi.volatile compounds produced by pseudomonas fragi strain 18 in sterile fish muscle (sebastes melanops) were identified by combined gas-liquid chromatography and mass spectrometry. compounds positively identified included dimethyl sulfide, acetaldehyde, ethyl acetate, ethyl alcohol, and dimethyl disulfide. methyl mercaptan, ethyl butyrate, ethyl hexanoate, and butanone were tentatively identified by relative retention times of the authentic compounds. the fruity odor that developed in fish muscle ...19734736793
ultrastructural localization of an extracellular protease in pseudomonas fragi by using the peroxidase-antiperoxidase extracellular protease, which previously has been found to correlate with the appearance of bleblike evaginations on the cell wall of pseudomonas fragi atcc 4973, was purified 38-fold by ammonium sulfate precipitation and sephadex chromatography to yield a single band by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. polyclonal rabbit antiserum raised against the purified enzyme had an enzyme-linked immunosorbent assay titer of 4 x 10(7). the peroxidase antiperoxidase method was u ...19853909961
action of pseudomonas fragi on the proteins of pig muscle.considerable salt-soluble protein degradation was observed in pork muscle inoculated with pseudomonas fragi. during a 20-day incubation period at 10 c, the samples proceeded to rank spoilage or putrefaction. there was a large decrease in the salt-soluble protein fraction and a corresponding increase in nonprotein nitrogen. disc gel electrophoretic patterns showed that breakdown of the salt-soluble proteins had occurred after incubation for 20 days. during incubation for 10 days at 10 c, p. fragi ...19714938102
effect of an elevated level of carbon dioxide containing atmosphere on the growth of spoilage and pathogenic bacteria at 2, 7, and 13 c.the effect of 80% co2 (balance air) on the survival and growth of microorganisms most often associated with spoilage and foodborne disease in poultry carcasses was compared to air at 2, 7, and 13 c. the co2 atmosphere substantially retarded the growth of the total bacterial load in uninoculated ground chicken meat and parts at all temperatures when compared to air; however, temperature had a larger overall effect than atmosphere. ground chicken meat and synthetic broth were inoculated (greater t ...19863090536
effects of selected food additives on growth of pseudomonas fragi. 19694974935
fatty acid composition of lipid synthesized by pseudomonas fragi. 19715141442
cloning, sequencing and expression of the lipase gene from pseudomonas fragi ifo-12049 in e. coli.the lipase gene from pseudomonas fragi ifo-12049 was isolated using the expression library and the primary structure of lipase deduced from the nucleotide sequence was determined. it is composed of 277 amino acid residues and a protein of mr 29,966, which was close to the value of the lipase expressed in e. coli.19883060375
sequence of the d-aspartyl/l-isoaspartyl protein methyltransferase from human erythrocytes. common sequence motifs for protein, dna, rna, and small molecule s-adenosylmethionine-dependent methyltransferases.a widely distributed protein methyltransferase catalyzes the transfer of a methyl group from s-adenosyl-methionine to the free carboxyl groups of d-aspartyl and/or l-isoaspartyl derivatives of l-aspartyl and l-asparaginyl residues. this enzyme has been postulated to function in the repair or the catabolism of age-damaged proteins. we present here the complete amino acid sequence of the more basic isozyme i of this enzyme from human erythrocytes. the sequence was determined by edman degradation a ...19892684970
the extracellular nature of the lipase of pseudomonas fragi. 19655881339
inhibition of microbial lipases by fatty acids.addition of lard or sodium oleate to the medium used for lipase production by pseudomonas fragi resulted in a decreased accumulation of lipase in the culture supernatant fluid without affecting cell growth. the production and activity of lipase was inhibited by lard, sodium oleate, and the salts of other unsaturated fatty acids. some divalent cations, tweens, lecithin, and bovine serum prevented oleate inhibition, but did not reverse it. similar inhibitory actions were observed with geotrichum c ...19665970458
thermal resistance of pseudomonas fragi in milk containing various amounts of fat.similar populations of pseudomonas fragi were grown at 25 c for 20 hr or at 7 c for 7 days in milk containing 0, 10, and 20% fat; they were then heated at 48, 50, and 52 c in milk containing 0, 10, and 20% fat. after inoculation, the heating medium contained 2.1 x 10(6) to 6.9 x 10(6) organisms per milliliter. the p. fragi cells grown in skim milk had greater thermal resistance (d(52) = 3.0 to 3.1) than those grown in milk containing fat (d(52) = 1.9 to 2.5). the organisms grown at 7 c for 7 day ...19666013210
purification and characterization of the lipase of pseudomonas fragi. 19676052627
specificity of endoproteinase asp-n (pseudomonas fragi): cleavage at glutamyl residues in two proteins.endoproteinase asp-n, a metalloprotease from a mutant strain of pseudomonas fragi, has been reported to specifically cleave on the n-terminal side of aspartyl and cysteic acid residues. we utilized this enzyme to generate fragments for determining the amino acid sequence of the d-aspartyl/l-isoaspartyl methyltransferase isozyme i from human erythrocytes. surprisingly, we identified cleavage sites for this enzyme at the n-terminal side of several glutamyl residues in addition to the expected clea ...19892669754
esterification of chiral secondary alcohols with fatty acid in organic solvents by polyethylene glycol-modified lipase.lipase from pseudomonas fragi 22.39b was modified with polyethylene glycol. the modified lipase (peg-lipase) was soluble and active in organic solvents such as benzene and 1,1,1-trichloroethane. peg-lipase catalyzed esterification of chiral secondary alcohols with fatty acids in benzene and exhibited preference for r isomers over s isomers. km and vmax values for each isomer of various alcohols were obtained by kinetic study of the esterification in benzene. peg-lipase-catalyzed esterification l ...19892635854
a numerical taxonomic study of proteolytic and lipolytic psychrotrophs isolated from caprine milk.lipolytic and proteolytic psychrotrophs were isolated from raw and pasteurized goats' milk, which had been stored at 5 degrees c for 7 d. the 241 strains isolated and 20 reference strains were examined by 149 biochemical, physiological, and morphological tests. the results yielded 195 characters suitable for taxonomic analysis. computer-assisted complete linkage analysis, using the jaccard coefficient, produced 22 phenons at 75% s. the results showed that pseudomonas fluorescens was the predomin ...19892496069
centroid search optimization of cultural conditions affecting the production of extracellular proteinase by pseudomonas fragi atcc 4973.the production of extracellular proteinase by pseudomonas fragi atcc 4973 grown in a defined citrate medium, containing glutamine as the sole nitrogen source, was determined under varying cultural conditions. simultaneous evaluation of cultural conditions using a 'centroid search' optimization technique showed that the optimum cultural conditions for proteinase production by ps. fragi were: incubation temperature, 12.5 degrees c; incubation time, 38 h; initial ph, 6.8; organic nitrogen concentra ...19902292518
scanning electron microscope study of pseudomonas fragi on intact and sarcoplasm-depleted bovine longissimus dorsi muscle.intact bovine longissimus dorsi muscle strips used 24 h postmortem were washed to remove sarcoplasmic fluid or left intact and were either left uninoculated or inoculated with pseudomonas fragi atcc 4973. the effects of decreased sarcoplasm concentration on growth of p. fragi and consequent microstructural changes of beef muscle during aerobic storage at 4 degrees c for 12 days were evaluated. p. fragi grew slower on washed muscle than on intact muscle. scanning electron micrographs revealed sur ...19827081988
structure of the glycocalyx polysaccharide of pseudomonas fragi atcc 4973.the structure of the exocellular glycocalyx polysaccharide of pseudomonas fragi atcc 4973, a bacterium implicated in the spoilage of meat, has been determined using hydrolysis, methylation analysis and 1d- and 2d-n.m.r. spectroscopy. the polysaccharide, which aids in the adhesion of the cells to each other and to the meat tissue, has the regular repeating unit ----4)-3-o-[(r)-1-carboxyethyl]-alpha-d-glcp-(1----3)-beta-d-manpnac+ ++- (1----4)-beta-d-glcp-(1----. random partial o-acetylation occur ...19911797390
production of proteases by psychrotrophic microorganisms.six milk-derived psychrotrophic microbial cultures were screened for the ability to grow at refrigerated temperatures and produce proteases in reconstituted skim milk. of these, two cultures, pseudomonas fluorescens m3/6 and pseudomonas fragi k122, produced extracellular protease(s) beginning 7 d postinoculation when the cultures had entered late log or early stationary phases of growth. further work with these two cultures showed that intracellular proteases were present after only 20-h incubat ...19911744258
induction of enzymes involved in fatty acid beta-oxidation in pseudomonas fragi b-0771 cells grown in media supplemented with fatty acid.induction of the enzymes involved in fatty acid beta-oxidation in pseudomonas fragi b-0771 cells grown in a medium containing straight chain saturated fatty acids was studied. the acyl-coa dehydrogenase (acdh) activity was induced during the exponential phase in cells grown in palmitic acid-supplemented medium, reached a maximum at the early stationary phase, and then gradually decreased thereafter. changes in the overall activities of 2-enoyl-coa hydratase and 3-hydroxyacyl-coa dehydrogenase, b ...19921607360
lactic acid inhibition of the growth of spoilage bacteria and cold tolerant pathogens on pork.the antibacterial effects of a 3% solution of lactic acid at 55 degrees c were assessed, by examining aerobic bacterial growth on artificially-inoculated pork fat and lean tissue. discs of fat or lean tissues, each of 10 cm2 surface area, were aseptically excised from pork longissimus dorsi muscle and inoculated with the cold tolerant pathogens listeria monocytogenes 4b scott a no. 3, yersinia enterocolitica 0:4,32 or aeromonas hydrophila atcc 7966, or with the wild type spoilage bacteria pseudo ...19957547145
isolation of an extracellular neutral proteinase from pseudomonas fragi.a single proteolytic enzyme (ec 3.4.4.-) was isolated from culture supernatants of pseudomonas fragi with 20% yielded and 60-fold purification by means of stepwise deae-sephadex batch adsorption, ammonium sulfate precipitation, gel filtration and deae-cellulose chromatography. the enzyme was zn-2+ activated and ca-2+ stabilized, had optimum activity at ph 6.5--8.0 and 40 degrees c. the molecular weight range was 40 000--50 000 as determined by dodecylsulfate gel electrophoresis, gel filtration ...1975236771
isolation and properties of the protease from the wild-type and mutant strains of pseudomonas fragi.a simplified procedure for the purification of the extracellular protease of pseudomonas fragi was developed. the enzyme was isolated from a derepressed mutant producing 40 times the enzyme level of the parental organism. it was collected from culture filtrates by ammonium sulfate precipitation, and it was obtained in pure form by single chromatography on a column of diethylaminoethyl cellulose. the protease had a molecular weight of 52,000 as estimated by sodium dodecyl sulfate-gel electrophore ...197942639
effects of homologous bacteriophage on growth of pseudomonas fragi wy in milk.pseudomonas fragi strain wy and its homologous bacteriophage were added in varying concentrations to sterile skim milk which was stored at 7 c for 72 hr. when the initial concentration of the bacterial host was 100,000/ml, addition of as few as 10 plaque-forming units per ml of bacteriophage resulted in significantly lower counts in treated skim milk than in the controls which contained no phage. there was no significant effect, however, when the phage input was 1 in 10 ml and the bacterial coun ...19734568889
proteolytic enzyme preparation from pseudomonas fragi: its action on pig extracellular preparation from pseudomonas fragi with proteolytic enzyme activity was isolated, and its action on meat proteins and meat protein ultrastructure was studied. first, a suitable growth medium for proteolytic enzyme production was determined, and a method for partial purification of the proteolytically active fraction was developed. the enzyme preparation displayed optimal proteolytic activity at neutral ph and 35 c. proteolytic activity was irreversibly lost by mild heat treatmen ...19734716726
conversion of dexon (p-dimethylaminobenzenediazo sodium sulfonate) to n, n-dimethyl-p-phenylenediamine by pseudomonas fragi bk9.the metabolism of the fungicide dexon (p-dimethylaminobenzenediazo sodium sulfonate) by a soil bacterium is reported for the first time. the organism which is capable of using dexon only by a co-metabolic process was obtained by enrichment culture and was identified as pseudomonas fragi. the first metabolic product of dexon was identified as n,n-dimethyl-p-phenylenediamine. the presence of an enzyme, p-dimethylaminobenzenediazo sodium sulfonate reductase, capable of reducing dexon to n,n-dimethy ...19744809909
isolation from food sources, of lactic acid bacteria that produced antimicrobials.the potential of lactic acid bacteria, isolated from a variety of foods, to inhibit indicators representative of spoilage and pathogenic bacteria associated with food products was examined. fruit and vegetables were a poor source of lactic acid bacteria but large numbers were readily isolated on mrs agar from cheese, milk and meat samples. approximately 1000 isolates from each of the food samples were examined by the deferred antagonism procedure to determine their ability to inhibit staphylococ ...19948144413
temperature-dependent anomalies in the growth of microorganims.davey, c. b. (north carolina state university, raleigh), raymond j. miller, and larry a. nelson. temperature-dependent anomalies in the growth of microorganisms. j. bacteriol. 91:1827-1830. 1966.-water in the liquid phase (0 to 100 c) has been shown, by others, to undergo subtle changes in its physical structure at approximately 15, 30, 45, and 60 c. it has been suggested that these temperature-dependent anomalies in the structure of water may have biological implications. after incubation in a ...19664957023
glucose, the key substrate in the microbiological changes occurring in meat and certain meat products.the literature dealing with the role of glucose in the microbiological changes of meat and certain meat products is reviewed. discussion is centered on two aspects. first, glucose plays a part in the selection of the dominant spoilage organisms, pseudomonas fragi, ps. lundensis, and ps. fluorescens, on red meat stored aerobically under chill (2-7 degrees c) conditions. it is concluded that the pseudomonads flourish because they convert glucose to the less commonly used substrate, gluconate. the ...19883293613
ester production by pseudomonas fragi. iv. demonstration of esterase activity.assay of the esterase activity of sonically treated cell-free extracts, whole cell suspensions, and supernatant fluid of pseudomonas fragi cultures with a differential respirometer revealed that the esterases were intracellular. polyacrylamide-gel electrophoresis demonstrated six bands of esterase activity, which revealed substrate specificity differences. band 1 exhibited slow mobility, bands 2, 3, and 4 moderate mobility, and bands 5 and 6 rapid mobility. six bands were active with alpha-napht ...19705498602
ester production by pseudomonas fragi. ii. factors influencing ester levels in milk cultures.cultures of pseudomonas fragi were grown at 21 c in sterile homogenized milk and reconstituted skim milk media supplemented with ethyl alcohol. quantitative determinations of ethyl butyrate and ethyl hexanoate by gas-liquid chromatography showed definite increases in the concentrations of the two esters produced in these media in comparison to media not supplemented with ethyl alcohol. supplementation with butyric acid in addition to ethyl alcohol generally elevated the ethyl butyrate concentrat ...19695819608
lethal effect of butylated hydroxyanisole as related to bacterial fatty acid composition.bacillus cereus, clostridium perfringens, staphylococcus aureus, pseudomonas fluorescens, pseudomonas fragi, escherichia coli, and salmonella "anatum" were challenged with butylated hydroxyanisole (bha). susceptibility was measured as the concentration of bha required to cause a 90% reduction in bacterial survivors. staphylococcus aureus lp and p. fragi were two of the most resistant species examined; c. perfringens and p. fluorescens were the most susceptible. gram stain reaction was found not ...19862873790
production of hydrogen peroxide by lactobacillus acidophilus.hydrogen peroxide production in reconstituted skim milk (10%) and low-fat milk by four strains lf lactobacillus acidophilus was studied at 37 and 4 c. strains a and b produced little, but strains c and d produced larger amounts, especially if agitated continuously during growth at 37 c or storage at 4 c. continuous shaking was required at 4 c for c or d (4.0 x 10(8)/ml) to produce sufficient hydrogen peroxide to retard growth of pseudomonas fragi. flavin adenine dinucleotide stimulated the oxida ...19806768778
effect of high concentrations of carbon dioxide on growth rate of pseudomonas fragi, bacillus cereus and streptococcus cremoris. 19806773917
the influence of temperature on the growth inhibitory effect of carbon dioxide on pseudomonas fragi and bacillus cereus.the growth inhibitory effect of 50 kpa (0.5 atm) co2 was tested for pseudomonas fragi in the temperature range 5-35 degrees c and of 101 kpa (1 atm) co2 on bacillus cereus in the range 18-46 degrees c. the maximum specific growth rate (mumax) of p. fragi in air (ph 6.7) was 0.44 h-1 at 35c, 0.66 h-1 at 30 degrees c, and 0.078 h-1 at 5 degrees c. in 50 kpa of co2 in air the relative inhibition of the growth rate was about 30% at 35 degrees c, 50% at 30 degrees c, and 90% at 5 degrees c. thus, the ...19816783284
classification of the spoilage flora of fish, with special reference to shewanella hundred and fifty-nine gram-negative strains isolated from refrigerated fish, taken from the baltic sea or swedish inland waters, together with 32 reference strains of shewanella, pseudomonas, aeromonas and alcaligenes, were phenotypically classified using 124 unit characters. data were processed by the simple matching (ssm) and jaccard (sj) coefficients, and unweighted pair group algorithm with arithmetic averages. fourteen clusters were defined at the 75% sj similarity level which correspo ...19902391295
comparison of enrichment and plating media for isolation of yersinia.yersinia enterocolitica (serotypes 0:3 or 0:8), yersinia frederiksenii, yersinia kristensenii, or yersinia intermedia along with 10(8) cells of each of three extraneous organisms (escherichia coli, enterobacter aerogenes, pseudomonas fragi), all commonly found on market poultry, were inoculated into five enrichment media followed by streaking onto 11 plating media to determine the most-efficacious combinations for future surveys or assessment studies. for yersinia enterocolitica (0:8), infrequen ...19902356183
biological and clinical relevance of the urokinase-type plasminogen activator (upa) in breast cancer.tumor cell invasion and metastasis is a multifactorial process, which at each step may require the action of proteolytic enzymes such as collagenases, cathepsins, plasmin, or plasminogen activators. an enzymatically inactive proenzyme form of the urokinase-type plasminogen activator (pro-upa) is secreted by tumor cells which may be converted to an enzymatically active two-chain upa-molecule (hmw-upa) by plasmin-like enzymes. action of proteases on pro-upa may generate the enzymatically active or ...19911801751
attributes of microbial associations of meat growing as xenic batch cultures in a meat juice at 4 degrees c.strains of gram-positive (carnobacterium piscicola, leuconostoc mesenteroides subsp. mesenteroides, brochothrix thermosphacta) and gram-negative (pseudomonas fragi and hafnia alvei) bacteria isolated from minced lamb packaged under a modified atmosphere were cultivated in a meat (lamb) juice at 4 degrees c. carbohydrates were catabolised in the order glucose > glucose 6-phosphate during the development of the population. under an atmosphere enriched with carbon dioxide the gram-negative portion ...19957488524
numerical taxonomy of gram-negative, nonmotile, nonfermentative bacteria isolated during chilled storage of lamb carcasses.a numerical taxonomic study using 75 characters was performed with 132 strains of gram-negative, nonmotile, nonfermentative bacteria selected on the basis of lack of motility and gram reaction among 1,200 cultures isolated during aerobic storage of lamb carcasses. at the 80% similarity level (ssm), eight clusters were formed. strains in clusters 1 to 6 could be identified as members of the family moraxellaceae and, more specifically, as members of the psychrobacter-[moraxella] phenylpyruvica sub ...19921637162
lipase from pseudomonas fragi crda 323: partial purification, characterization and interesterification of butter fat.several strains of pseudomonas were screened for lipase production using the rhodamine agar diffusion test. on the basis of the diameter of the halo produced, p. fragi crda 323 and p. putida atcc 795 were considered to be good and weak lipase producers respectively. p. fragi, cultured in a 2-l fermenter, produced a maximal amount of lipase after 3-4 days of incubation at 27 degrees c. the lipase extract of p. fragi was obtained by acidification of culture supernatant at ph 4.0 and partially puri ...19957766135
use of long-chain fatty acid-coa ligase (amp-forming) from pseudomonas fragi for the 'in vitro' synthesis of natural penicillins.five different naturally occurring penicillins containing as side chains hexanoic, trans-3-hexenoic, heptanoic, octanoic or trans-3-octenoic acids have been synthesized 'in vitro' by coupling long-chain fatty acid-coa ligase (amp-forming) (ec from pseudomonas fragi (lfcoa-l) with acyl-coa: 6-aminopenicillanic acid acyltransferase (at) from penicillium chrysogenum. the quantity of penicillin produced was directly related with the carbon length of the side chain precursor tested, being ma ...19921327953
a sensitive assay of acyl-coenzyme a oxidase by coupling with beta-oxidation multienzyme complex.a highly sensitive and reliable method for assaying acyl-coa oxidase (ec activity was developed. an acyl-coa oxidase-dependent [1-14c]palmitoyl-coa degradation to acetyl-coa, acid-soluble products, was measured by coupling with the multienzyme complex for fatty acid oxidation from pseudomonas fragi. the activity, more than 2 pmol/min, could be assessed using this method. the activity was dependent on the coupling enzyme (multienzyme complex), coenzymes such as nad+ and coa, and oxygen, ...19947810878
isolation of the measles virus hemagglutinin protein in a soluble form by protease digestion.the hemagglutinin (h) glycoprotein was isolated in a soluble form by digesting measles virus particles with an endoproteinase, asp-n (from a pseudomonas fragi mutant). digestion of h with asp-n brought about glycopeptides in three different forms, depending on the cleaving site: ahd, which has an m(r) of 66,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and which formed a disulfide-linked homodimer with an m(r) of 132,000, and two monomeric digestion products, ahm ...19957983748
effect of growth temperatures on the protein levels in a psychrotrophic bacterium, pseudomonas fragi.pseudomonas fragi has the ability to grow between 0 and 35 degrees c and grows optimally at 30 degrees c. cellular proteins from mid-log-phase cells growing from 4 to 34 degrees c were labeled with l-[35s]methionine during 1 generation time and analyzed by two-dimensional gel electrophoresis. the electrophoretic patterns revealed differences in the patterns of protein synthesis over this temperature span. a qualitative comparison of cellular proteins led to their separation into five thermal cla ...19948021184
application of the random amplified polymorphic dna using the polymerase chain reaction for efficient elimination of duplicate strains in microbial screening. iii. bacteria.random amplified polymorphic dna (rapd) analysis was evaluated for the selection and elimination of bacterial strains used in microbial screening. for this pilot study we used eight bacterial strains producing fragin and two pseudomonas fragi strains, which are often isolated during the screening. a dendrogram constructed by the statistical analysis using parsimony, paup, based on the band patterns of rapd with primer r28 was in good correlation with the results of dna-dna hybridization, hplc an ...19948150715
a small, dilute-cytoplasm, high-affinity, novel bacterium isolated by extinction culture and having kinetic constants compatible with growth at ambient concentrations of dissolved nutrients in seawater.dilutions of raw seawater produced a bacterial isolate capable of extended growth in unamended seawater. its 2.9-mb genome size and 40-fg dry mass were similar to values for many naturally occurring aquatic organotrophs, but water and dna comprised a large portion of this small chemoheterotroph, as compared to escherichia coli. the isolate used only a few aromatic hydrocarbons and acetate, and glucose and amino acid incorporation were entirely absent, although many membrane and cytoplasmic prote ...19989797308
genetic characterization and heterologous expression of brochocin-c, an antibotulinal, two-peptide bacteriocin produced by brochothrix campestris atcc 43754.brochocin-c, produced by brochothrix campestris atcc 43754, is active against many strains of the closely related meat spoilage organism brochothrix thermosphacta and a wide range of other gram-positive bacteria, including spores of clostridium botulinum. purification of the active compound and genetic characterization of brochocin-c revealed that it is a chromosomally encoded, two-peptide nonlantibiotic bacteriocin. both peptides of brochocin-c are ribosomally synthesized as prepeptides that ar ...19989835559
molecular cloning and nucleotide sequence of the lipase gene from pseudomonas fragi.the gene coding for the lipase of pseudomonas fragi was cloned into escherichia coli jm83 by inserting sau3a-generated dna fragments into the bamh i site of puc9. the plasmid isolated, pkko, was restriction mapped and the position of the lipase gene on the 2.0 kb insert was pinpointed by subcloning. dna sequencing revealed that the open reading frame comprises 405 nucleotides and gives a preprotein of 135 amino acids with a predicted mr of 14643. by comparing the putative lipase amino acid seque ...19863800995
acquisition of iron by the non-siderophore-producing pseudomonas fragi.the iron requirement, siderophore production and iron uptake mechanisms of the type strain pseudomonas fragi atcc 4973 and five p. fragi isolates from meat were analysed. the strains exhibited a high sensitivity to iron starvation: their growth was strongly inhibited in medium supplemented with the iron chelator ethylenediamine di(hydroxyphenylacetic acid) or in medium treated with 8-hydroxyquinoline to remove contaminating iron. no siderophores were detectable in the growth supernatants of iron ...19968704960
spoilage bacteria of fresh broiler chicken carcasses.studies were conducted to identify the bacteria responsible for spoilage of fresh broiler chicken carcasses and to characterize the off-odors these bacteria produce. broiler carcasses were collected from processing plants in the northeast georgia area, the southeastern u.s., arkansas, california, and north carolina. the carcasses were allowed to spoil under controlled conditions at 3 c and spoilage bacteria were isolated. each spoilage bacterium was separately inoculated into a sterile chicken s ...19958825595
volatile compounds associated with microbial growth on normal and high ph beef stored at chill temperatures.volatile compounds produced by pseudomonas fragi and mixed, natural floras on beef of normal ph (5.5-5.8; glucose greater than 1500 micrograms/g) and high ph (6.3-6.8; glucose less than 10 micrograms/g) included a range of alkyl esters and a number of sulphur-containing compounds including dimethylsulphide but not hydrogen sulphide. production of the last was a property common to the other gram-negative organisms tested viz. hafnia alvei, enterobacter agglomerans, serratia liquefaciens, alteromo ...19892753835
human and murine class i mhc antigens share conserved serine 335, the site of hla phosphorylation in vivo.the site of phosphorylation of the hla-b7 antigen in vivo is serine 335, which is located in the intracellular region. pseudomonas fragi protease was used in limited proteolysis experiments of hla antigens to identify the position of the phosphoserine residue. the intracellular region is composed of 30 amino acids at the carboxyl terminus of the heavy chain; up to nine serine residues are located in this region. four of the serines are found at the distal end, and are encoded by exon 7 in both h ...19846430898
differential protein expression by pseudomonas fragi submitted to various stresses.we have analyzed the impact of various stressing conditions on the physiological and molecular responses of the main psychrotrophic spoilage bacterium of refrigerated meat and meat products, pseudomonas fragi. a survival study using conventional plating was first performed to select the stressing agents and parameters. some of these mimicked cleaning-disinfection processes but with less drastic conditions in order to keep alive enough bacterial cells for the protein expression characterization. ...199910493125
a new inhibitor of mitochondrial fatty acid oxidation.the mitochondrial enoyl-coa hydratase/3-hydroxyacyl-coa dehydrogenase/3-ketoacyl-coa thiolase trifunctional protein (trifunctional protein) plays a major role in mitochondrial fatty acid oxidation. the enzyme complex consists of four molecules of alpha-subunit containing both hydratase and dehydrogenase domains and four molecules of beta-subunit containing the thiolase domain. the primary structure of a gastrin-binding protein (gbp) was highly homologous to that of the alpha-subunit of the trifu ...19968827458
axenic aerobic biofilms inhibit corrosion of sae 1018 steel through oxygen depletion.corrosion inhibition of sae 1018 steel by pure-culture biofilms of pseudomonas fragi and escherichia coli dh5 alpha has been evaluated in complex luria-bertani medium, seawater-mimicking medium, and modified baar's medium at 30 degrees c. in batch cultures, both bacteria inhibited corrosion three to six fold compared to sterile controls, and the corrosion was comparable to that observed in anaerobic sterile media. to corroborate this result, a continuous reactor and electrochemical impedance spe ...19979274042
numerical taxonomy of psychrotrophic pseudomonads.the taxonomy of 218 psychrotrophic pseudomonad strains (200 field strains from meat and 18 type and reference strains) was numerically studied by 174 biochemical and physiological tests. all strains were gram-negative rods, oxidative positive and motile by means of one or more polar flagella. the strains clustered into 15 groups, of which 9 were regarded as major clusters. the major clusters were designated as pseudomonas fragi (112 strains), p. fluorescens biotype iii (7 strains), p. fluorescen ...19827119735
substrate specificity of a proteolytic enzyme isolated from a mutant of pseudomonas fragi.previous studies have described the isolation of mutationally altered proteases in pseudomonas fragi (noreau, j., and drapeau, g.r. (1979) j. bacteriol, 140, 911-916. in the present study, it is shown that one of these proteases cleaves specifically the peptide bonds on the nh2-terminal side of either aspartic acid or cysteic acid residues in oxidized ribonuclease. with myoglobin as the substrate, a similar specificity was observed except that only four out of the six aspartyl bonds present were ...19807188696
utilization of oligopeptides by listeria monocytogenes scott a.for effective utilization of peptides, listeria monocytogenes possesses two different peptide transport systems. the first one is the previously described proton motive force (pmf)-driven di- and tripeptide transport system (a. verheul, a. hagting, m.-r. amezaga, i. r. booth, f. m. rombouts, and t. abee, appl. environ. microbiol, 61:226-233, 1995). the present results reveal that l. monocytogenes possesses an oligopeptide transport system, presumably requiring atp rather than the pmf as the driv ...19989501445
identification of pseudomonads from fresh and chill-stored chicken carcasses.results of carbon source assimilation tests (17 carbon compounds) led to 88% of pseudomonads from cold-stored chicken carcasses being assigned to one of 17 groups. of these groups, 13 had combinations of properties identical to, or with readily recognizable degrees of similarity to those of published species/biovars. two of the four groups having carbon assimilation patterns dissimilar to any known species had cellular fatty acid composition corresponding to pseudomonas fluorescens, and two to p ...19989553797
growth of pseudomonas fluorescens and pseudomonas fragi in a meat medium as affected by ph (5.8-7.0), water activity (0.97-1.00) and temperature (7-25 degrees c).a total of 59 strains of pseudomonas, isolated from meat products, were grown in micro-titer plates in a meat medium over a range of ph (5.8-7.0), alpha w (0.97-1.00) and temperature (7-25 degrees c). growths were performed in a meat broth with an automated turbidimeter (bioscreen c, labsystem, france). the growth curves obtained in this study did not have sigmoidal shapes making it impossible to calculate growth parameters using the gompertz equation. the medium was weakly oxygenated in the mic ...19989562876
acyl coenzyme a synthetase from pseudomonas fragi catalyzes the synthesis of adenosine 5'-polyphosphates and dinucleoside polyphosphates.acyl coenzyme a (coa) synthetase (ec from pseudomonas fragi catalyzes the synthesis of adenosine 5'-tetraphosphate (p4a) and adenosine 5'-pentaphosphate (p5a) from atp and tri- or tetrapolyphosphate, respectively. datp, adenosine-5'-o-[gamma-thiotriphosphate] (atp gamma s), adenosine(5')tetraphospho(5')adenosine (ap4a), and adenosine(5')pentaphospho(5')adenosine (ap5a) are also substrates of the reaction yielding p4(d)a in the presence of tripolyphosphate (p3). utp, ctp, and amp are not ...19989620965
metabolic activities of pseudomonads in batch cultures in extract of minced lamb.pseudomonas fragi, ps. lundensis and ps. fluorescens were studied in axenic batch cultures growing in a lamb juice (ph 6.0) aerobically or in an atmosphere (ps. fragi only) enriched with carbon dioxide at 4 degrees c. with all but a glucose dehydrogenase-deficient strain of ps. fluorescens there was a sequential catabolism of glucose and lactate. diauxic growth was observed in a nutrient-deficient meat juice supplemented with glucose and lactate. a transient peak in the concentration of gluconat ...19947822220
transient sensitivity to nisin in cold-shocked gram negatives.rapid chilling in the presence of nisin caused a dose-dependent reduction in the populations of several gram-negative bacteria, despite the fact that appreciable structural injury to the outer membrane was not detected. pseudomonas aeruginosa was most affected, followed by pseudomonas fragi, salmonella enteritidis pt4, pt7 and escherichia coli, respectively. addition of nisin after the chilling treatment had no effect. the results are ascribed to a transient susceptibility caused by phase change ...200010972735
volatile components associated with bacterial spoilage of tropical prawns.analysis of headspace volatiles by gas chromatography/mass spectrometry from king (penaeus plebejus), banana (p. merguiensis), tiger (p. esculentus/semisulcatus) and greasy (metapenaeus bennettae) prawns stored in ice or ice slurry, which is effectively an environment of low oxygen tension, indicated the presence of amines at the early stages of storage (less than 8 days) irrespective of the nature of the storage media. esters were more prevalent in prawns stored on ice (normal oxygen conditions ...19989706797
antimicrobial properties of human lysozyme transgenic mouse milk.the antimicrobial properties of standard human lysozyme and the milk of transgenic mice expressing human lysozyme were investigated using bacterial strains important to the dairy industry. standard human lysozyme was found to be effective at significantly slowing the growth of the milk cold-spoilage organism pseudomonas fragi (p < 0.001), of a clinical isolate of the mastitis-causing organism staphylococcus aureus (p < 0.005), and a nonpathogenic strain of e. coli (p < 0.05). milk from transgeni ...19989708253
acyl-coa synthetase catalyzes the synthesis of diadenosine hexaphosphate (ap6a).the synthesis of diadenosine hexaphosphate (ap6a), a potent vasoconstrictor, is catalyzed by acyl-coa synthetase from pseudomonas fragi. in a first step amp is transferred from atp to tetrapolyphosphate (p4) originating adenosine pentaphosphate (p5a) which, subsequently, is the acceptor of another amp moiety from atp generating diadenosine hexaphosphate (ap6a). diadenosine pentaphosphate (ap5a) and diadenosine tetraphosphate (ap4a) were also synthesized in the course of the reaction. in view of ...199910385004
effect of growth temperature on hydrolytic and esterifying activities from pseudomonas fragi crda 037 grown on wheythe production of hydrolytic and esterifying activities of pseudomonas fragi crda 037 grown on a whey-based medium was investigated at different temperatures over time. the optimal temperature was found to be critical and different for the production of both activities. the highest hydrolytic activity was detected with bacteria cultivated at between 24 degrees c (149.2 u/liter) and 27 degrees c (133.8 u/liter), while the highest production of ethyl valerate (esterifying activity) was observed by ...199910388711
effect of different temperature upshifts on protein synthesis by the psychrotrophic bacterium pseudomonas fragipseudomonas fragi, a psychrotroph bacterium involved in meat product spoilage, was shifted either from 5degrees to 20degreesc or 30degreesc and from 28degrees to 34degreesc. the heat-shocked cells in the mid-log phase rapidly reached the characteristic growth rate of the postshock temperature. the patterns of synthesized proteins were compared by autoradiography of two-dimensional gel electrophoregrams. the rates of synthesis, after transfer of cells from 5degrees to 30degreesc, 5degrees to 20de ...19968661683
amplified fragment length polymorphism fingerprinting of pseudomonas strains from a poultry processing plant.molecular typing has been used previously to identify and trace dissemination of pathogenic and spoilage bacteria associated with food processing. amplified fragment length polymorphism (aflp) is a novel dna fingerprinting technique which is considered highly reproducible and has high discriminatory power. this technique was used to fingerprint 88 pseudomonas fluorescens and pseudomonas putida strains that were previously isolated from plate counts of carcasses at six processing stages and vario ...199910473382
attachment of bacteria to beef from steam-pasteurized carcasses.the extent to which a bacterial cocktail containing equal numbers of pseudomonas fragi nctc 10689, listeria monocytogenes bl5/2, salmonella typhimurium lt2, and escherichia coli jm 109 attached to loin surface cuts (7 by 5 cm) derived from steam-pasteurized beef carcasses has been evaluated. the extent of attachment was categorized as loosely attached (removed by rinsing), firmly attached (released by stomaching), and irreversibly bound. no significant difference (p > 0.10) in the attachment of ...200111307885
construction of environmental dna libraries in escherichia coli and screening for the presence of genes conferring utilization of 4-hydroxybutyrate.environmental dna libraries from three different soil samples were constructed. the average insert size was 5 to 8 kb and the percentage of plasmids with inserts was approximately 80%. the recombinant escherichia coli strains (approximately 930,000) were screened for 4-hydroxybutyrate utilization. thirty-six positive e. coli clones were obtained during the initial screen, and five of them contained a recombinant plasmid (pah1 to pah5) which conferred a stable 4-hydroxybutyrate-positive phenotype ...199910473393
inhibiting sulfate-reducing bacteria in biofilms on steel with antimicrobial peptides generated in batch and continuous fermentations, the reduction in corrosion of sae 1018 mild steel and 304 stainless steel caused by inhibition of the reference sulfate-reducing bacterium (srb) desulfovibrio vulgaris by a protective, antimicrobial-producing bacillus brevis biofilm was investigated. the presence of d. vulgaris produced a thick black precipitate on mild steel and a higher corrosion rate in batch cultures than that seen in a mono-culture of non-antimicrobial-producing pseudomonas fragi k upo ...199910499267
the gene for albicidin detoxification from pantoea dispersa encodes an esterase and attenuates pathogenicity of xanthomonas albilineans to sugarcane.albicidin phytotoxins are pathogenicity factors in a devastating disease of sugarcane known as leaf scald, caused by xanthomonas albilineans. a gene (albd) from pantoea dispersa has been cloned and sequenced and been shown to code for a peptide of 235 amino acids that detoxifies albicidin. the gene shows no significant homology at the dna or protein level to any known sequence, but the gene product contains a gxsxg motif that is conserved in serine hydrolases. the albd protein, purified to homog ...19979275238
the cold shock response of the psychrotrophic bacterium pseudomonas fragi involves four low-molecular-mass nucleic acid-binding proteins.the psychrotrophic bacterium pseudomonas fragi was subjected to cold shocks from 30 or 20 to 5 degrees c. the downshifts were followed by a lag phase before growth resumed at a characteristic 5 degrees c growth rate. the analysis of protein patterns by two-dimentional gel electrophoresis revealed overexpression of 25 or 17 proteins and underexpression of 12 proteins following the 30- or 20-to-5 degrees c shift, respectively. the two downshifts shared similar variations of synthesis of 20 protein ...19979393697
continuous recording of long-chain acyl-coenzyme a synthetase activity using fluorescently labeled bovine serum albumin.the fluorescence-based long-chain fatty acid probe bsa-hca (bovine serum albumin labeled with 7-hydroxycoumarin-4-acetic acid) is shown to respond to binding of long-chain acyl-coa thioesters by quenching of the 450 nm fluorescence emission. as determined by spectrofluorometric titration, binding affinities for palmitoyl-, stearoyl-, and oleoyl-coa (kd = 0.2-0.4 microm) are 5-10 times lower than those for the corresponding nonesterified fatty acids. in the presence of detergent (chaps, triton x- ...200111476543
antimicrobial actions of degraded and native chitosan against spoilage organisms in laboratory media and foods.the objective of this study was to determine whether chitosan (poly-beta-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly degraded products of chitosan exhibited no antimicrobial activ ...200010618206
the growth and resistance to sodium hypochlorite of listeria monocytogenes in a steady-state multispecies biofilm.a constant-depth film fermenter (cdff) was used to culture a steady-state multispecies biofilm consisting of one strain each of listeria monocytogenes, pseudomonas fragi and staphylococcus xylosus. these bacteria were initially grown together in a conventional chemostat to achieve a steady state before being inoculated into the cdff over an 18-h period. a dilute tryptone soya broth (tsb) medium was supplied to the cdff and the biofilm allowed to develop over a 28-d period. this mature biofilm wa ...200010747232
combined effects of nacl, naoh, and biocides (monolaurin or lauric acid) on inactivation of listeria monocytogenes and pseudomonas spp.this study highlighted combinations of chemical stresses that could decrease or eliminate listeria monocytogenes and pseudomonas spp. surviving in food processing plants. strains of l. monocytogenes, pseudomonas fragi, and pseudomonas fluorescens isolated from processing environments (meat and milk) were grown at 20 degrees c up to the early stationary phase. the strains were then subjected to 30 min of physicochemical treatments. these treatments included individual or combined acid (acetic aci ...200111563526
shewanella putrefaciens adhesion and biofilm formation on food processing surfaces.laboratory model systems were developed for studying shewanella putrefaciens adhesion and biofilm formation under batch and flow conditions. s. putrefaciens plays a major role in food spoilage and may cause microbially induced corrosion on steel surfaces. s. putrefaciens bacteria suspended in buffer adhered readily to stainless steel surfaces. maximum numbers of adherent bacteria per square centimeter were reached in 8 h at 25 degrees c and reflected the cell density in suspension. numbers of ad ...200111319118
genetic characterization and evolutionary implications of a car gene cluster in the carbazole degrader pseudomonas sp. strain ca10.the nucleotide sequences of the 27,939-bp-long upstream and 9,448-bp-long downstream regions of the caraaaababbcac(orf7)ad genes of carbazole-degrading pseudomonas sp. strain ca10 were determined. thirty-two open reading frames (orfs) were identified, and the car gene cluster was consequently revealed to consist of 10 genes (caraaaababbcacaddfe) encoding the enzymes for the three-step conversion of carbazole to anthranilate and the degradation of 2-hydroxypenta-2,4-dienoate. the high identities ...200111371531
pathogenic yersinia species carry a novel, cold-inducible major cold shock protein tandem gene duplication producing both bicistronic and monocistronic mrna.inverse pcr was used to amplify major cold shock protein (mcsp) gene families from a diverse range of bacteria, including the psychrotolerant yersinia enterocolitica, which was found to have two almost identical mcsp coding regions (cspa1 and cspa2) located approximately 300 bp apart. this tandem gene duplication was also found in y. pestis, y. pseudotuberculosis, and y. ruckeri but not in other bacteria. analysis of the transcriptional regulation of this mcsp gene in y. enterocolitica, performe ...199910515936
adherence to stainless steel by foodborne microorganisms during growth in model food systems.biofilm formation on stainless steel by salmonella typhimurium, listeria monocytogenes, escherichia coli o157:h7, pseudomonas fragi and pseudomonas fluorescens during growth in model food systems was studied. test growth media included tryptic soy broth (tsb), diluted tsb (dtsb), 1% reconstituted skim milk (rsm) and diluted meat juice (dmj). adherent cells were stained with acridine orange and enumerated using epifluorescent microscopy and computerized image analysis. cells were observed on the ...19979310849
microbiological methods for testing disinfectant efficiency on pseudomonas biofilm.biofilms of the gram-negative bacteria pseudomonas aeruginosa and pseudomonas fragi were grown on stainless steel surfaces (aisi 304, 2b) for 4 days in slime broth. these biofilms were treated with four commercial disinfectants. the disinfectants were alcohol-based, tenside-based, peroxide-based and chlorine-based products, covering most disinfectant types used in the food industry. the effects of the disinfectants on the bacterial cells were first investigated in suspension using the permeabili ...200111084307
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