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PubMed1990

Temperate bacteriophages and lysogeny in lactic acid bacteria.

Lysogeny is widespread in the lactic acid bacteria. The majority of lysogens can be induced by UV irradiation or treatment with mitomycin C, but indicator strains which allow lytic growth of the induced phage are often not easy to identify. A few temperate phages have been shown to transduce chromosomal and/or plasmid markers. Information about the molecular biology of the temperate phages from lactic acid bacteria is sparse and needs significant supplementation in order that these potentially valuable phages might be utilized more efficiently as tools for improving existing starter strains in dairy fermentations.

Amino Acid Sequence↗

PubMed2003

Fed-batch fermentation of Lactobacillus lactis for hyper-production of L-lactic acid.

A fed-batch fermentation of Lactobacillus lactis to produce L-lactic acid was developed in which the residual glucose concentration in the culture was used to control a continuous feeding strategy. Up to 210 g L-lactic acid l(-1) (97% yield) was obtained. The maximal dry cell was 2.7 g l(-1) and the average L-lactic acid productivity was 2 g l(-1) h(-1).

Bioreactors↗

PubMed1983

Lactic acid bacteria of meat and meat products.

When the growth of aerobic spoilage bacteria is inhibited, lactic acid bacteria may become the dominant component of the microbial flora of meats. This occurs with cured meats and with meats packaged in films of low gas permeability. The presence of a flora of psychrotrophic lactic acid bacteria on vacuum-packaged fresh chilled meats usually ensures that shelf-life is maximal. When these organisms spoil meats it is generally by causing souring, however other specific types of spoilage do occur. Some strains cause slime formation and greening of cured meats, and others may produce hydrogen sulphide during growth on vacuum-packaged beef. The safety and stability of fermented sausages depends upon fermentation caused by lactic acid bacteria. Overall the presence on meats of lactic acid bacteria is more desirable than that of the types of bacteria they have replaced.

Animals↗

PubMed1988

Elevated cerebrospinal fluid lactic acid levels in Creutzfeldt-Jakob disease.

The concentration of cerebrospinal fluid (CSF) lactic acid was determined in three patients with biopsy proven Creutzfeldt-Jacob disease (CJD). When compared with twenty demented patients diagnosed as having either Alzheimer's disease or multi-infarct dementia, the CSF lactic acid values of the CJD patients were significantly elevated (p less than .001). Elevated CSF lactic acid levels may be an important biochemical marker of CJD and useful in the differential diagnosis of dementia.

Aged↗

PubMed1994

Peritoneal fluid lactic acid and diagnostic dilemmas in acute abdominal disease.

Our previous canine research suggested that the determination of peritoneal fluid lactic acid levels may be helpful in the evaluation of potential acute abdomen cases. To investigate the clinical significance of those findings, we obtained simultaneous peritoneal and plasma lactic acid values from patients undergoing emergency celiotomy or in whom surgical consultation was sought to rule out an acute abdomen. The lactic acid value was significantly higher in peritoneal fluid than in plasma in patients who were found to have hollow viscus perforation, gangrenous intestine, peritonitis, or intra-abdominal abscess. In contrast, the values were similar in patients who did not have those conditions. Our findings suggest that the calculated difference between simultaneous peritoneal and plasma lactic acid values is a helpful diagnostic index for patients in whom the diagnosis of acute abdomen is not otherwise obvious.

Abdomen, Acute↗

PubMed1976

Correlation of maternal physical fitness during pregnancy with maternal and fetal pH and lactic acid at delivery.

The physical fitness of 120 healthy primigravidae was determined two weeks before term using first the standardized three-stage submaximal work test on the following day the voluntarily maximal pulse-conducted work test on a bicycle ergometer. After the first test the level of lactic acid in the capillary circulation of 115 mothers was examined. Immediately after delivery the pH and the level of lactic acid in the maternal artery, umbilical vein and umbilical artery were determined. The level of lactic acid after the work test was negatively correlated with the physical performance of the mother. The level of lactic acid in the mother after the work test and the levels of lactic acid in the umbilical vessels were positively correlated. The mean pH value in physically fit women after delivery was almost significantly higher than in the women of below average performance. The pH level in the umbilical artery was also almost significantly higher in the mothers with above average performance. The physically fit women appear to work more during delivery than the less fit mothers, as the level of lactic acid after the delivery was as high as or higher than in mothers with a physical performance below average. The physical fitness of six mothers, who delivered an asphyxiated baby, was almost significantly lower than the performance of the mothers. Five mothers with an exceptionally high pH after delivery had a significantly higher performance than the other mothers.

Adult↗

PubMed1998

Synergistic antimicrobial effect of nisin whey permeate and lactic acid on microbes isolated from fish.

The antimicrobial activity of a combination of lactic acid and whey permeate fermented by a nisin-producing Lactococcus lactis strain was tested by the agar diffusion method using bacteria isolated from fish as test organisms. Lactic acid inhibited all bacterial strains studied, but nisin whey permeate inhibited Gram-positive bacteria only. The combination was more effective than lactic acid alone against Pseudomonas fluorescens and Staphylococcus hominis isolated from fish, and Pseudomonas aeruginosa ATCC9721 and Micrococcus luteus ATCC9341.

Animals↗

PubMed1989

Antibiosis of some lactic acid bacteria including Lactobacillus acidophilus toward Listeria monocytogenes.

Eleven strains of lactic acid bacteria were tested by the 'spot' on the 'lawn' method for their antagonistic activity against four strains of Listeria monocytogenes. Four out of the five strains of lactic acid bacteria most antagonistic toward the pathogen were those cultures known to produce bacteriocins. Four other strains of lactic acid bacteria were not antagonistic against Listeria by this method. Seventeen inhibition zones of the pathogen were obtained at 25 degrees C as compared to 10 at 32 degrees C. Lactobacillus acidophilus strains NU-A and 88, growing in the presence of L. monocytogenes in milk prevented the latter from attaining populations it would have in pure culture (P less than 0.01). 10(1.4)-10(3.5) lower numbers were noted. L. acidophilus in most cases exhibited a bacteriostatic effect toward the pathogen except for strain 88 which appeared to have a bactericidal effect (P less than 0.01) against Listeria strain OH. The lactobacilli reduced the pH of the milk to 4.7 over a 24 h period, showing that acid played a role in the observed antibiosis.

Animals↗

PubMed2006

Lactic acid production from cellulosic material by synergetic hydrolysis and fermentation.

The hydrolysis process on corncob residue was catalyzed synergetically by the cellulase from Trichoderma reesei and the immobilized cellobiase. The feedback inhibition to cellulase reaction caused by the accumulation of cellobiose was eliminated efficiently. The hydrolysis yield of corncob residue was 82.5%, and the percentage of glucose in the reducing sugar reached 88.2%. The glucose in the cellulosic hydrolysate could be converted into lactic acid effectively by the immobilized cells of Lactobacillus delbrueckii. When the enzymatic hydrolysis of cellulose and the fermentation of lactic acid were coupled together, no glucose was accumulated in the reaction system, and the feedback inhibition caused by glucose was also eliminated. Under the batch process of synergetic hydrolysis and lactic acid fermentation with 100 g/L of cellulosic substrate, the conversion efficiency of lactic acid from cellulose and the productivity of lactic acid reached 92.4% and 0.938 g/ (L.h), respectively. By using a fed-batch technique, the total concentration of cellulosic substrate and lactic acid in the synergetic process increased to 200 and 107.5 g/L, respectively, whereas the dosage of cellulase reduced from 20 to 15 IU/g of substrate in the batch process. The results of the bioconversion of renewable cellulosic resources were significant.

Bioreactors↗

PubMed2004

Unusual D-lactic acid acidosis from propylene glycol metabolism in overdose.

OBJECTIVE: To report a case of D-lactic acid acidosis owing to massive oral ingestion of propylene glycol. CASE REPORT: A 72-year old man with known congestive failure was admitted to the ICU with encephalopathy. Twelve hours prior to admission he had erroneously ingested a large amount of propylene glycol (PG). The laboratory revealed high anion gap (anion gap = 27 meq/l) acidosis (arterial pH = 7.16) and an increased osmolal gap. Toxicological analysis revealed a low serum propylene glycol level. Biochemical analysis indicated that very high amounts of D-lactic acid (up to 110 mmol/l), but not of the usual type of L-lactic acid, were responsible for the metabolic acidosis. Hemodialysis was initiated and associated with a decline of both the acidosis and D-lactic acid levels. The patient regained conciousness. CONCLUSION: Ingestion of massive doses of propylene glycol, previously not reported as a cause of D-lactic acidosis, should be added to the differential diagnosis of this rare condition.

Acidosis, Lactic↗

PubMed1990

Genetics of lactic acid bacteria with special reference to lactococci.

Lactic acid bacteria play an important role in the manufacture of fermented foods. Genetic studies have made these microorganisms, particularly lactococci, accessible to genetic manipulation. The instability of key metabolic traits of lactococci has been explained by the presence of plasmid DNA species. Most genetic interest has been focused to solve the quoted instability and the sensitivity to bacteriophage infection. At the same time, gene transfer systems have been developed and specific genes with commercial significance have been identified and cloned. Lactic acid bacteria can be also used as production organisms of heterologous proteins, e.g. chymosin, lysozyme.

Bacterial Proteins↗

PubMed1999

The long-term interaction of dental cements with lactic acid solutions.

A study of the interaction of dental cements with lactic acid solutions has been carried out in which individual cement specimens were repeatedly exposed to 20 mmol dm(-3) lactic acid for periods of a week. After each week of storage, the mass of the specimens was recorded and the pH of the solution determined. The glass-ionomers showed an initial increase in mass, followed by a decline that became steady from 6 weeks. Zinc polycarboxylate and zinc phosphate cements, by contrast, showed no early gain in mass, but eroded steadily more or less from the start of their exposure to lactic acid. For all cements, acid erosion followed linear kinetics, at rates ranging from 0.5%/week for the zinc phosphate to 0.28%/week for one of the glass-ionomers, Chelonfil (ESPE, Germany). At the end of six months, the zinc phosphate had lost 14.2% of its initial mass, the zinc polycarboxylate 9.9% and the glass-ionomers between 6.2 and 7.2%. Erosion was accompanied on every occasion by neutralization of the acid solution. Both erosion and neutralization continued steadily throughout the experiment. The effectiveness of neutralization was in the following order: zinc polycarboxylate>zinc phosphate>glass-ionomer. The pH change in Week 1 was much greater for the glass-ionomers and the zinc polycarboxylate than in all subsequent weeks.

Journal Article↗

PubMed2004

Biotechnological production of L(+)-lactic acid from wood hydrolyzate by batch fermentation of Enterococcus faecalis.

The inhibition of lactic acid fermentation by wood hydrolyzate was decreased (approx. 20%) by adaptation of Enterococcus faecalis RKY1 to wood hydrolyzate-based medium whereby lactic acid productivity and cell growth were enhanced by 0.5 g l(-1) h(-1) and 2.1 g l(-1), respectively. When the diluted or concentrated wood hydrolyzate (equivalent to 25-100 g glucose l(-1)) was supplemented with 15 g yeast extract l(-1), 24-93 g lactic acid l(-1) was produced at a rate between 1.7 g l(-1) h(-1) and 3.2 g l(-1) h(-1).

Adaptation, Physiological↗

PubMed1983

Lactic acid concentrations in vitreous humor: their use in asphyxial deaths in children.

Lactic acid concentrations in brain tissue of humans have been shown to increase with an extended agonal period. Infants and children dying from various causes are undergoing different stress conditions terminally and the postulate of this study is that natural death cases and traumatic asphyxia cases are characterized by varying agonal periods, the former being somewhat prolonged with the latter being rather brief. One-hundred-and-two cases of infants and children were examined for vitreous humor lactic acid concentrations. They were divided into two major categories, Sudden Infant Death Syndrome (SIDS) and non-SIDS cases. SIDS was further divided into SIDS without additional findings and SIDS with secondary findings which contributed to death. The non-SIDS category included traumatic asphyxia cases as well as those dying from blunt trauma, known respiratory diseases, and other causes. Categorical mean values and standard deviations were calculated. The vitreous humor lactic acid mean value for traumatic asphyxia was significantly lower than the mean value for SIDS. Also the mean value for known respiratory diseases was statistically lower than the mean value for SIDS with secondary findings. These findings are probably suggestive of agonal time differences and may be a reflection of the various mechanisms of death.

Asphyxia↗

PubMed1990

Health and nutritional benefits from lactic acid bacteria.

There are several potential health or nutritional benefits possible from some species of lactic acid bacteria. Among these are: improved nutritional value of food, control of intestinal infections, improved digestion of lactose, control of some types of cancer, and control of serum cholesterol levels. Some potential benefits may result from growth and action of the bacteria during the manufacture of cultured foods. Some may result from growth and action of certain species of the lactic acid bacteria in the intestinal tract following ingestion of foods containing them. In selecting a culture to produce a specific benefit it is necessary to consider not only the wide variation among species of the lactic acid bacteria but also that among strains within a given species. With the possible exception of improving lactose utilization by persons who are lactose maldigestors, no specific health or nutritional claims can yet be made for the lactic acid bacteria.

Cholesterol↗

PubMedDate not supplied

Hydroxyapatite surface modified by L-lactic acid and its subsequent grafting polymerization of L-lactide.

A new method of surface modification of hydroxyapatite nanoparticles (n-HA) by surface grafting reaction of l-lactic acid and ring-opening polymerization of l-lactide (LLA) was developed. Two modified HA nanoparticles were obtained: HA modified by l-lactic acid (l-HA) and HA grafting with poly(l-lactide) (PLLA; p-HA). The modified surface of n-HA was attested by Fourier transformation infrared, (31)P MAS NMR, and thermal gravimetric analysis. The results showed that l-lactic acid could be easily grafted onto the n-HA surface by forming a Ca carboxylate bond and initiated by the hydroxyl group of the grafted l-lactic acid and LLA could be graft-polymerized onto the n-HA surface in the presence of stannous octanoate. The highest grafting amounts of l-lactic acid and PLLA were about 33 and 22 wt %, respectively. The modified HA/PLLA composites showed good mechanical properties and uniform microstructure. The tensile strength and modulus of the p-HA/PLLA composite containing 15 wt % of p-HA were 67 MPa and 2.1 GPa, respectively, while those of the n-HA/PLLA composites were 45 MPa and 1.7 GPa, respectively. The elongation at the break of the l-HA/PLLA composite containing 15 wt % l-HA could reach 44%, in comparison with 6.5% of the n-HA/PLLA composites containing 15 wt % n-HA.

Durapatite↗

PubMed2006

Phenotypic and technological diversity of lactic acid bacteria and staphylococci isolated from traditionally fermented sausages in southern Greece.

The physicochemical and microbiological characteristics of spontaneously fermented sausages made by two medium-sized enterprises (MSE) located in southern Greece have been studied. A total of 300 lactic acid bacteria and 300 staphylococcal strains have been isolated and identified by their physiological characteristics. Lactobacillus plantarum strains were found to dominate the lactic acid bacteria microbiota in most of the cases with L. sakei strains prevailing in some of them and L. rhamnosus strains occasionally accompanying the dominant lactic acid bacteria microbiota. On the other hand, S. saprophyticus strains were found to dominate the staphylococcal microbiota in all spontaneously fermented sausages with of S. simulans, S. xylosus, S. gallinarum and S. cohnii cohnii strains being sporadically present. Following the identification, an evaluation of their technological properties, namely proteolytic and lipolytic capacities as well as production of biogenic amines and antimicrobial compounds, took place. None of the lactic acid bacteria and staphylococci was found to possess lipolytic activity whereas a total of 6 lactic acid bacteria and 51 staphylococci strains were found to be able to hydrolyse either the sarcoplasic, myofibrillar or both protein fractions. Furthermore, only one L. sakei strain and 185 staphylococci strains were found to possess decarboxylase activity against lysine, tyrosine, ornithine or histidine. Finally none of the staphylococcal microbiota and 3 lactic acid bacteria strains were found to be able to produce antimicrobial compounds of proteinaceous nature against Listeria monocytogenes.

Animals↗

PubMed1998

Taxonomy and physiology of probiotic lactic acid bacteria.

The current taxonomy of probiotic lactic acid bacteria is reviewed with special focus on the genera Lactobacillus, Bifidobacterium and Enterococcus. The physiology and taxonomic position of species and strains of these genera were investigated by phenotypic and genomic methods. In total, 176 strains, including the type strains, have been included. Phenotypic methods applied were based on biochemical, enzymatical and physiological characteristics, including growth temperatures, cell wall analysis and analysis of the total soluble cytoplasmatic proteins. Genomic methods used were pulsed field gel electrophoresis (PFGE), randomly amplified polymorphic DNA-PCR (RAPD-PCR) and DNA-DNA hybridization for bifidobacteria. In the genus Lactobacillus the following species of importance as probiotics were investigated: L. acidophilus group, L. casei group and L. reuteri/L. fermentum group. Most strains referred to as L. acidophilus in probiotic products could be identified either as L. gasseri or as L. johnsonii, both members of the L. acidophilus group. A similar situation could be shown in the L. casei group, where most of the strains named L. casei belonged to L. paracasei subspp. A recent proposal to reject the species L. paracasei and to include this species in the restored species L. casei with a neotype strain was supported by protein analysis. Bifidobacterium spp. strains have been reported to be used for production of fermented dairy and recently of probiotic products. According to phenotypic features and confirmed by DNA-DNA hybridization most of the bifidobacteria strains from dairy origin belonged to B. animalis, although they were often declared as B. longum by the manufacturer. From the genus Enterococcus, probiotic Ec. faecium strains were investigated with regard to the vanA-mediated resistance against glycopeptides. These unwanted resistances could be ruled out by analysis of the 39 kDa resistance protein. In conclusion, the taxonomy and physiology of probiotic lactic acid bacteria can only be understood by using polyphasic taxonomy combining morphological, biochemical and physiological characteristics with molecular-based phenotypic and genomic techniques.

Bifidobacterium↗