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PubMed1999

Isolation of thermophiles degrading poly(L-lactic acid).

A thermophile, strain 93, which degrades poly(L-lactic acid) (PLA) film was isolated from 144 soil samples obtained from different locations by cultivation using an enrichment culture medium at 60 degrees C. Under this temperature condition, the strain grew on PLA and the dissolved total organic carbon (TOC) concentration in the medium changed according to the growth stage, i.e., after the TOC rapidly reached the minimum, it increased rapidly until it reached the peak and then decreased thereafter. For residual PLA, reduced viscosity decreased rapidly but weight decreased initially slowly with a gradually increasing rate. Gel permeation chromatograms showed a marked decrease in the main peak and the appearance of a new peak in the low molecular weight region. The strain was identified as Bacillus brevis, which has an optimum growth temperature of around 58 degrees C.

Journal Article↗
PubMed2001

Synthesis and characterisation of a degradable poly(lactic acid)-poly(ethylene glycol) copolymer with biotinylated end groups.

Poly(lactic acid)-poly(ethylene glycol)-biotin (PLA-PEG-biotin) is a degradable polymer with protein resistant properties that can undergo rapid surface engineering in aqueous media to create biomimetic surfaces. Surface engineering of this polymer is dependent on biomolecular interactions between the biotin end group and the protein avidin. Given the vigorous conditions of synthesis, it is essential that the manufacture of the polymer does not alter the biotin structure or its molecular recognition. Equally, it is important that the incorporation of biotin does not adversely affect the physicochemical properties of the polymer. (1)H NMR provides evidence of biotin attachment and structural integrity. (1)H NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) analysis shows there is no significant effect on bulk properties induced by the biotin end group. Surface plasmon resonance (SPR) and fluorescent spectroscopy studies using the 2-(4'-hydroxyazobenzene) benzoic acid (HABA)/avidin complex show that the biotin moieties binding capabilities are not impaired by the synthesis.

Avidin↗
PubMed2002

Isolation and characterization of lactic acid bacteria from feces of newborn baby and from dongchimi.

Lactic acid bacteria were screened from feces of newborn baby and from dongchimi. Selection criteria employed included the ability of strains to withstand environmental conditions such as low pH, high bile concentration, and oxygen. The isolates were applied to the juice of various vegetables, and fermentabilities of isolates were compared. Strains F20-3, F35-3, and F35-6 showed high stability compared to the other strains at pH 3.0 and 2.3. Strains D1 and D2 showed the highest survival at pH 3.0 and survived at 1% high bile concentration. The selected strains were able to survive at low pH and relatively high bile concentration and were not affected by oxygen. The growth of isolates was >10(7) cfu/mL in natural media, and strains were not affected by the pH values of the vegetables. Therefore, isolated strains are thought to survive through the intestinal ecosystem and are considered to be suitable for application of the fermented product using various vegetables for their functionality. The isolates were identified as Lactobacillus plantarum and Lactobacillus fermentum.

Bifidobacterium↗
PubMed2000

Bacteriocin production by lactic acid bacteria isolated from Rioja red wines.

Forty-two lactic acid bacteria (LAB) of the genera Lactobacillus (32), Leuconostoc (6), Pediococcus (3) and Lactococcus (1), isolated from Rioja red wines, were tested for antimicrobial activity. All these strains, as well as 18 Leuconostoc oenos and 19 yeast strains were used as indicators. Only nine strains showed antimicrobial activity, and all were of the species Lactobacillus plantarum, which constitutes the predominant microflora in Rioja red wines after alcoholic fermentation. Lact. plantarum strain J-51 showed the widest range of action, inhibiting the growth of 31 strains of the four studied LAB genera. Lact. plantarum J-51 antimicrobial activity was lost after treatment with proteases, suggesting a proteinaceous nature for this activity. It was found to be stable between pH 3 and 9 and under strong heating conditions (100 degrees C for 60 min). Polymerase chain reaction (PCR) analysis of Lact. plantarum J-51 genome revealed the presence of the plnA gene that encodes the plantaricin precursor PlnA. A 366-bp fragment was sequenced and showed 95% identity with pln locus of Lact. plantarum C-11. The deduced precursor peptide sequence showed one mutation (Gly7 to Ser7) at the double glycine leader peptide, and the three putative 26-, 23- and 22-residue active peptides remain identical to those of Lact. plantarum C-11. Therefore, antimicrobial peptides constitute a potent adaptation advantage for those strains that dominate in a medium such as wine, and can play an important role in the ecology of wine microflora.

Amino Acid Sequence↗
PubMed2002

Pediocin PA-1, a wide-spectrum bacteriocin from lactic acid bacteria.

Pediocin PA-1 is a broad-spectrum lactic acid bacteria bacteriocin that shows a particularly strong activity against Listeria monocytogenes, a foodborne pathogen of special concern among the food industries. This antimicrobial peptide is the most extensively studied class Ila (or pediocin family) bacteriocin, and it has been sufficiently well characterized to be used as a food biopreservative. This review focuses on the progress that have been made in the elucidation of its structure, mode of action, and biosynthesis, and includes an overview of its applications in food systems. The aspects that need further research are also addressed. In the future, protein engineering, genetic engineering and/or chemical synthesis may lead to the development of new antimicrobial peptides with improved properties, based on some features of the pediocin PA-1 molecule.

Amino Acid Sequence↗
PubMed1995

Development of RAPD protocol for typing of strains of lactic acid bacteria and enterococci.

A protocol for typing strains of lactic acid bacteria and enterococci based on randomly amplified polymorphic DNA (RAPD) fragments has been developed. Using a single 10-mer primer, fingerprints were achieved without the need to isolate genomic DNA. Different conditions of DNA release and amplification were investigated in order to obtain reproducible results and high discrimination among strains. This RAPD protocol was successfully applied for the typing of strains belonging to the species Lactobacillus acidophilus, Lact. helveticus, Lact. casei, Lact. reuteri, Lact. plantarum, Enterococcus faecalis, Ent. faecium and Streptococcus thermophilus.

Bacterial Typing Techniques↗
PubMed2004

Isolation and characterization of anti-Salmonella lactic acid bacteria from the porcine gastrointestinal tract.

AIMS: To identify lactic acid bacteria (LAB) of porcine intestinal origin with anti-Salmonella activity. METHODS AND RESULTS: Samples were obtained from pig faeces and caeca and screened for the presence of anti-Salmonella LAB. The 11 most promising isolates were identified as belonging to the genera Lactobacillus and Pediococcus. The LAB exhibited large variation in their ability to survive in simulated gastric juice at pH 1.85. While Lactobacillus johnsonii species survived at levels of 80% for up to 30 min, Lactobacillus pentosus species declined to <0.001% in that time. All isolates tolerated porcine bile at a concentration of 0.3% (w/v), with some isolates capable of growth in the presence of up to 5% (w/v) bile. The ability of the LAB isolates to prevent Salmonella invasion of intestinal epithelial HT-29 cells varied, with reductions of between 30% (Lact. pentosus) and 80% (Lactobacillus murinus spp.) observed. CONCLUSIONS: LAB of porcine origin were observed to survive simulated passage through the GIT and inhibit growth of Salmonella and its invasion of the intestinal epithelium. SIGNIFICANCE AND IMPACT OF THE STUDY: The data demonstrate that some porcine intestinal LAB isolates may offer potential as probiotics for the reduction of Salmonella carriage in pigs.

Animals↗
PubMed1981

Entrance and growth of lactic Acid bacteria in gas-exchanged, brined cucumbers.

Entrance of lactic acid bacteria into the interior of brined cucumbers was found to be greatly influenced by gas composition of the cucumbers before brining. Exchange of the internal gas of fresh cucumbers with O(2) resulted in absorption of bacteria into the subsequently brined fruit within a few hours. Bacteria were absorbed into nonexchanged cucumbers to a lesser extent. Little bacterial absorption occurred in N(2)-exchanged cucumbers. Stomata of the cucumber skin appeared to be a likely port for bacterial entry. When Pediococcus cerevisiae or Lactobacillus plantarum cells were added to the brine of O(2)-exchanged cucumbers, the respective cell types colonized in large numbers within intercellular spaces and vascular elements of mesocarp tissue during fermentation of the cucumbers. Implications of these observations, particularly with regard to bloater formation in brined cucumbers, are discussed.

Journal Article↗
PubMed2000

Use of green fluorescent protein to tag lactic acid bacterium strains under development as live vaccine vectors.

The lactic acid bacteria (LAB) are safe microorganisms which are mainly used for the preparation of fermented foods and for probiotic applications. The potential of LAB as live vehicles for the production and delivery of therapeutic molecules such as antigens is also being actively investigated today. However, very little is known about the fate of live LAB when administered in vivo and about the interaction of these microorganisms with the nasal or gastrointestinal ecosystem. For future applications, it is essential to be able to discriminate the biotherapeutic strain from the endogenous microflora and to unravel the mechanisms underlying the postulated health-beneficial effect. We therefore started to investigate both aspects in a mouse model with two LAB species presently under development as live vaccine vectors, i.e., Lactococcus lactis and Lactobacillus plantarum. We have constructed different expression vectors carrying the gfp (green fluorescent protein [GFP]) gene from the jellyfish Aequoria victoria, and we found that this visible marker was best expressed when placed under the control of the inducible strong nisA promoter from L. lactis. Notably, a threshold amount of GFP was necessary to obtain a bright fluorescent phenotype. We further demonstrated that fluorescent L. plantarum NCIMB8826 can be enumerated and sorted by flow cytometry. Moreover, tagging of this strain with GFP allowed us to visualize its phagocytosis by macrophages in vitro and ex vivo and to trace it in the gastrointestinal tract of mice upon oral administration.

Animals↗
PubMed1979

Correlation of aqueous humour lactic acid dehydrogenase activity with intraocular pathology.

An analysis of the lactic acid dehydrogenase (LDH) activity in the aqueous humour of 24 enucleated eyes with retinoblastoma showed that though there was no relationship between the LDH levels and the age of the patient, there appeared to be an increase in the LDH activity with increase in the duration of the tumour. Undifferentiated tumour cells and tumour cell necrosis seemed to contribute to an increase of LDH levels in the aqueous humour, but there was no relationship between the occurrence of calcification and the LDH secretion into the aqueous humour. Massive cell necrosis caused by radiotherapy and central retinal artery occlusion significantly increased the LDH levels in the aqueous. It also appeared that recurrence was common after external cobalt therapy and that secondary extension of the tumour into the optic nerve and choroid was favoured by this procedure.

Age Factors↗
PubMed2002

The groESL operon of the halophilic lactic acid bacterium Tetragenococcus halophila.

The groESL operon of the halophilic lactic acid bacterium Tetragenococcus halophila was cloned by a PCR-based method. The molecular masses of GroES and GroEL proteins were calculated to be 10,153 and 56,893 Da, respectively. The amount of groESL mRNA was increased 3.8-fold by heat shock (45 degrees C), and 4-fold by high NaCl (3-4 M). The Bacillus subtilis sigmaA-like constitutive promoter existed in front of groES, and was used under both normal and stress (heat shock and high salinity) conditions.

Amino Acid Sequence↗
PubMed1980

Serum lactic acid dehydrogenase and isoenzymes during pregnancy and labor.

Total serum lactic acid dehydrogenase activity (LDH) and the levels of LDH isoenzymes were investigated in 14 women during early pregnancy (8--16th week), in 28 women during late pregnancy (29--37th week), in 73 at term (38--42nd week) and in 27 during labor (38--42nd week). LDH activity was found to be elevated in severe pre-eclampsia and in chronic hypertensive women during pregnancy as well as during normal and dysfunctional labor. No change was established in total serum LDH during normal pregnancy. LDH 1 was increased during late pregnancy and at term. In severe pre-eclampsia and during normal labor it was decreased. LDH 2 was also decreased in severe pre-eclampsia and during dysfunctional labor. LDH 3 was decreased during late pregnancy but increased in severe pre-eclampsia. No change was observed in LDH 4 during pregnancy, or in labor. LDH 5 was increased in normal and dysfunctional labor.

Adult↗
PubMed2001

[The construction and application of promoter-signal peptide probe vector of lactic acid bacteria].

A promoter-signal peptide probe vector of lactic acid bacteria, designated pZLB based on pMG36e has been constructed. The vector contained a reporterd gene encoding for beta-lactamase, which lacked a promoter and a functional signal sequence. Sau3A restriction fragments (80-400 bp) from L. lactis ATCC 7962 total DNA were cloned into BamHI site of pZLB. A lot of different size framents were selected. These fragments promoted transcription and secretion of beta-lactamase in L. lactis. Sequence analysis revealed that inserted fragment in pZLBe7 contained typical promoter, SD sequence and atypical signal sequence.

Amino Acid Sequence↗
PubMedDate not supplied

[Expression vector pLF22 for the lactic acid bacteria].

The construction of the expression vector pLF22 for lactic acid bacteria is described. The vector contains a replicon of the cryptic plasmid pLF1311 from Lactobacillus fermentum and a multiple cloning site of the lacZ' gene integrated with the plasmid rep operon. Such a construction of the vector provides for the constitutive transcription of the cloned sequences lacking the terminators of transcription in all the strains that maintain the replication of the vector. The vector is suitable for a wide range of gram-positive and gram-negative bacteria, including probiotic strains. The efficiency of the vector was verified by expressing the beta-galactosidase gene in a laboratory Escherichia coli strain and the synthetic gene of somatotropin releasing factor (SRF) in the probiotic strains of lactobacilli and enterococci. A recombinant strain with the SRF gene included in the diet of laboratory animals exerted an effect on their physiological and anthropometric parameters and on the histological characteristics of animal tissues.

Animals↗
PubMed2002

Antifungal activity of the fermentation product of herbs by lactic acid bacteria against tinea.

The fermentation product of herbs by lactic acid bacteria (FHL), in which Enterococcus faecalis TH10 predominated, was assayed for antifungal activity against tinea. The antifungal activity of FHL was as high as that of a synthetic fungicide. Autoclaving FHL did not reduce its antifungal activity, whereas neutralizing it did. The results suggested that nonproteinaceous compounds or organic acids in FHL could inhibit the growth of the dermatophyte tinea under low-pH conditions, and that malonic acid and acetic acid could have especially high antifungal activity against tinea.

Journal Article↗
PubMed2006

Improvement of an experimental colitis in rats by lactic acid bacteria producing superoxide dismutase.

The use of superoxide dismutases (SODs) in inflammatory diseases is hampered by their short circulatory half-life. To determine whether a bacterial supply of SOD into the colon might improve an experimental colitis, the effects of oral treatment with live recombinant lactic acid bacteria producing different amounts of SOD and those of colonic infusion of SOD were compared. Wistar rats were fitted with a catheter in the proximal colon through which TNBS was administered to induce colitis. Animals received a continuous intracolonic infusion of bovine SOD (40 U per rat per day) for 4 days after TNBS or were treated orally with live recombinant Lactococcus lactis or Lactobacillus plantarum strains (10 colony-forming units (CFU)/d), producing or not producing SOD, for 4 days before and after TNBS. SOD activity of bacterial extracts was 0, 26, 74, and 624 units/10 CFU for L. plantarum, L. lactis, L. lactis SOD, and L. plantarum SOD, respectively. Four days after TNBS, macroscopic and microscopic damage, myeloperoxidase (MPO) activity, and nitrotyrosine immunostaining were evaluated. TNBS induced macroscopic and microscopic damages, an increase in MPO activity, and intense immunostaining for nitrotyrosine. Macroscopic damage and MPO activity were reduced by bovine SOD. These parameters and microscopic damages also were reduced by L. lactis, L. lactis SOD, and L. plantarum SOD, but not by L. plantarum. Nitrotyrosine immunostaining was attenuated after treatment with the 4 bacterial strains. Although not all of the anti-inflammatory effects could be attributed directly to SOD, our results suggest that SOD-producing lactic acid bacteria open a novel approach in inflammatory bowel disease treatment.

Administration, Oral↗
PubMed2004

Real-time PCR detection of lactic acid bacteria in cecal contents of eimeria tenella-lnfected broilers fed soybean oligosaccharides and soluble soybean polysaccharides.

This experiment was conducted to test whether dietary soybean meal oligosaccharides (SMO) and water-soluble polysaccharides (SMP) can assist broiler chickens in resisting Eimeria tenella, and to determine the survival of lactic acid bacteria in cecal contents postinfection. All birds received a soybean meal-free diet. The 6 experimental treatments were as follows: positive (COR) and negative (COW) control groups, 2 groups fed diets containing either 1% SMO or 0.5% SMP from 1 to 11 d of age; a vaccinated group (VAC), and an anticoccidial medicated group (ANT). Chickens of all treatments except COW were orally infected with 1000 sporulated oocysts of E. tenella on d 15. Fecal oocyst shedding was monitored per treatment group between d 5 and 13 postinfection. Lactic acid bacteria (LAB) in cecal contents were evaluated by a real-time PCR technique on d 7 postinfection. The results showed that the SMO and SMP groups had a lower number of oocysts per gram of feces during the monitoring period than the COR group. Threshold cycles were 22.21, 27.68, 13.99, 14.92, 12.97, and 14.85, for COW, COR, SMO, SMP, VAC, and ANT groups, respectively; specific PCR products were confirmed by the results of melting curve analysis and agarose gel electrophoresis. The results suggest that these LAB communities were promoted by SMO and SMP and have a competitive exclusion function when broiler chickens are infected with E. tenella.

Animal Feed↗
PubMed2006

Layered open pore poly(L-lactic acid) nanomorphology.

This paper reports on specific open and interconnected CO(2) foams of poly(L-lactic acid). The effect of varying gas concentration and hence physical changes induced by CO(2) has been investigated and thus used to generate specific structures. The developed morphologies have a skin core structure with larger pores in the core and open and interconnected smaller pores in the skin.

Carbon Dioxide↗