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Biomedical subjects

B Pot

Publications and source records attributed to B Pot.

At least 19 recordsLinked to original sources
PubMed2006

Modulation of allergic immune responses by mucosal application of recombinant lactic acid bacteria producing the major birch pollen allergen Bet v 1.

BACKGROUND: Probiotic lactic acid bacteria (LAB) are able to modulate the host immune system and clinical trials have demonstrated that specific strains have the capacity to reduce allergic symptoms. Therefore, we aimed to evaluate the potential of recombinant LAB producing the major birch pollen allergen Bet v 1 for mucosal vaccination against birch pollen allergy. METHODS: Recombinant Bet v 1-producing Lactobacillus plantarum and Lactococcus lactis strains were constructed. Their immunogenicity was compared with purified Bet v 1 by subcutaneous immunization of mice. Intranasal application of the live recombinant strains was performed to test their immunomodulatory potency in a mouse model of birch pollen allergy. RESULTS: Bet v 1 produced by the LAB was recognized by monoclonal anti-Bet v 1 and IgE antibodies from birch pollen-allergic patients. Systemic immunization with the recombinant strains induced significantly lower IgG1/IgG2a ratios compared with purified Bet v 1. Intranasal pretreatment led to reduced allergen-specific IgE vs enhanced IgG2a levels and reduced interleukin (IL)-5 production of splenocytes in vitro, indicating a shift towards non-allergic T-helper-1 (Th1) responses. Airway inflammation, i.e. eosinophils and IL-5 in lung lavages, was reduced using either Bet v 1-producing or control strains. Allergen-specific secretory IgA responses were enhanced in lungs and intestines after pretreatment with only the Bet v 1-producing strains. CONCLUSIONS: Mucosal vaccination with live recombinant LAB, leading to a shift towards non-allergic immune responses along with enhanced allergen-specific mucosal IgA levels offers a promising approach to prevent systemic and local allergic immune responses.

Administration, Intranasal↗
PubMed2004

The in vivo use of the stable isotope-labelled biomarkers lactose-[15N]ureide and [2H4]tyrosine to assess the effects of pro- and prebiotics on the intestinal flora of healthy human volunteers.

Amongst the various claimed beneficial effects of pro- and prebiotics for the human host, it has been hypothesised that functional foods are able to suppress the generation and accumulation of toxic fermentation metabolites (NH3, p-cresol). Direct evidence supporting this hypothesis is lacking mainly because of the unavailability of reliable biomarkers. Preliminary data indicate that lactose-[15N]ureide and [2H4]tyrosine may be potential biomarker candidates. The aim of the present study was to evaluate the effect of pro- and prebiotics on the colonic fate of these biomarkers in a randomised, placebo-controlled, cross-over study with nineteen healthy volunteers. At the start of the study and at the end of each 2-week study period, during which they were administered either a probiotic (n 10; 6.5 x 10(9) Lactobacillus casei Shirota cells twice daily) or a prebiotic (n 9; lactulose 10 g twice daily), the volunteers consumed a test meal containing the two biomarkers. Urine was collected during 48 h. Results were expressed as percentage of the administered dose. As compared with the placebo, the decrease in the percentage dose of p-[2H4]cresol in the 24-48 h urine fraction was significantly higher after probiotic intake (P=0.042). Similar changes were observed for the 15N tracer (P=0.016). After prebiotic intake, a significantly higher decrease in the percentage dose of p-[2H4]cresol (P=0.005) and 15N tracer (P=0.029) was found in the 0-24 h urine collection. The present results demonstrate that suppression of the generation and accumulation of potentially toxic fermentation metabolites by pro- and prebiotics can reliably be monitored in vivo by the use of stable isotope-labelled biomarkers.

Adult↗
PubMed2003

Identification and antibiotic susceptibility of bacterial isolates from probiotic products.

In the present study, a total of 55 European probiotic products were evaluated with regard to the identity and the antibiotic resistance of the bacterial isolates recovered from these products. Bacterial isolation from 30 dried food supplements and 25 dairy products, yielded a total of 268 bacterial isolates selected from several selective media. Counts of food supplements showed bacterial recovery in 19 (63%) of the dried food supplements ranging from 10(3) to 10(6) CFU/g, whereas all dairy products yielded growth in the range of 10(5)-10(9) CFU/ml. After identification of the isolates using whole-cell protein profiling, mislabeling was noted in 47% of the food supplements and 40% of the dairy products. In six food supplements, Enterococcus faecium was isolated whereas only two of those products claim this species on their label. Using the disc diffusion method, antibiotic resistance among 187 isolates was detected against kanamycin (79% of the isolates), vancomycin (65%), tetracycline (26%), penicillinG (23%), erythromycin (16%) and chloramphenicol (11%). Overall, 68.4% of the isolates showed resistance against multiple antibiotics including intrinsic resistances. Initially, 38% of the isolated enterococci was classified as vancomycin resistant using the disc diffusion method, whereas additional broth dilution and PCR assays clearly showed that all E. faecium isolates were in fact vancomycin susceptible.

Anti-Bacterial Agents↗
PubMed2003

Probiotics as biotherapeutic agents: present knowledge and future prospects.

Since the early observations of Elie Metchnikoff, a wealth of experiments have described the use of selected microorganisms, mainly belonging to the lactic acid bacteria family, for the prevention or treatment of a variety of pathological situations. Nevertheless, the mechanisms underlying the proposed actions remain vastly unknown, partly as a consequence of the complexity of the gastro-intestinal ecosystem with which these biotherapeutic agents are expected to interact, but also because of the increasing variety of strains considered to have potential probiotic characteristics. During the past decades, however, the beneficial effect of specific strains in preventing or treating intestinal disorders has been substantiated by well-controlled clinical trials. Increasing evidence, including human studies, is also supporting the immunomodulatory role attributed to given lactic acid bacterial strains. The desire by consumers to use natural methods for health maintenance rather than long-term chemotherapeutic agents (i.e. antibiotics), linked to their expectation that food becomes a source of prolonged well-being, supports the speculation that the probiotic market will expand rapidly. Much of this growth will also depend on the reliability of claims that these products will bare. Therefore, the legislator will have to provide clear rules and regulations which will depend on measurable biomarkers and criteria based on scientific evidence. These commercial and legislative needs will hopefully provide scientists with the resources necessary to conduct the multidisciplinary research required to establish facts and mechanisms of action for carefully selected probiotic strains. These research results will probably be as essential for the positioning of probiotic preparations as either a food, a food supplement or as pharmaceutical preparation.

Animals↗
PubMed2001

Identification of lactic acid bacteria constituting the predominating microflora in an acid-fermented condiment (tempoyak) popular in Malaysia.

Tempoyak is a traditional Malaysian fermented condiment made from the pulp of the durian fruit (Durio zibethinus). Salt is sometime added to proceed fermentation at ambient temperature. In various samples obtained from night markets, lactic acid bacteria (LAB) were the predominant microorganisms, ranging from log 8.4 to log 9.2 cfu g(-1). No other microorganisms were present to such a level. These samples contained reduced amount of saccharose, glucose and fructose but increased amount of D- and L-lactic acid and acetic acid compared with samples of non-fermented durian fruit. Sixty-four isolates of LAB were divided into five groups by use of a few phenotypic tests. A total of 38 strains of LAB were selected for comparison by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of their whole cell protein patterns with a SDS-PAGE database of LAB. These strains were also examined for their carbohydrate fermentation patterns by use of API 50 CH. Isolates belonging to the Lactobacillus plantarum group were shown to be the predominant members of the LAB flora. In addition, isolates belonging to the Lactobacillus brevis group, Leuconostoc mesenteroides, Lactobacillus mali, Lactobacilus fermentum and an unidentified Lactobacillus sp. were also observed. A high degree of diversity among isolates belonging to the Lb. plantarum group was demonstrated by analysis of their plasmid profiles.

Colony Count, Microbial↗
PubMed2001

Enterococcus villorum sp. nov., an enteroadherent bacterium associated with diarrhoea in piglets.

The taxonomic positions of five enteroadherent bacterial pig isolates, showing phenotypic characteristics most similar to those of Enterococcus durans and Enterococcus hirae, were investigated in a polyphasic study that included 16S rDNA sequence analysis, DNA-DNA hybridizations, DNA base-ratio determinations, whole-cell protein fingerprinting, D11344-primed PCR typing and an extensive examination of phenotypic properties. The results demonstrated that the organisms represent a new species in the Enterococcus faecium species group, for which the name Enterococcus villorum sp. nov. is proposed. The type strain is LMG 12287T (= CCM 4887T).

Animals↗
PubMed2000

Polyphasic characterization of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (p(HB-co-HV)) metabolizing and denitrifying Acidovorax sp. strains.

For the purpose of denitrification in small drinking water plants, a bacterial mixed population was isolated from a packed bed column bioreactor with poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P(HB-co-HV)) as a substrate for the denitrification of ground water (10 degrees C). Isolates 2nIII from the mixed culture, with the ability to denitrify and metabolize P(HB-co-HV), were used as starter cultures for the elimination of nitrate in ground water. The strains were characterized by diverse techniques. Classical phenotypic studies lead to rRNA group III of the genus Pseudomonas. Results obtained by molecular techniques demonstrated that the 2nIII strains are members of the Comamonadaceae and shows similarities to the genus Acidovorax. However, an integration of the 2nIII isolates within one of the known Acidovorax species is not possible for the moment. The 2nIII starter cultures clustered close to Av. temperans according to their whole cell proteins and fatty acids, whereas in DNA/DNA hybridization no significant DNA binding (< 25%) was found. In contrast a significant but low degree of DNA/DNA hybridization was found between the 2nIII strains and Av. facilis and Av. delafieldii. Our polyphasic results lead to the conclusion that the 2nIII strains may constitute a separate Acicdovorax species.

Bacterial Typing Techniques↗
PubMed1999

Identification of aesculin-hydrolyzing streptococci, lactococci, aerococci and enterococci from subclinical intramammary infections in dairy cows.

Aesculin-hydrolyzing, catalase-negative, gram-positive cocci isolated from subclinical intramammary infections in dairy cows were identified to species level using growth characteristics and biochemical activity. The results indicated that the aesculin-hydrolyzing cocci associated with this type of infection are a very heterogenic group. S. uberis strains, including inulin- or beta-glucuronidase-negative isolates, accounted for only about one-third of the collection, and Enterococcus faecalis strains for one-fifth. Other species of some importance included (in descending order of isolation frequency) Aerococcus viridans, Streptococcus pluranimalium, Lactococcus garvieae, Streptococcus bovis and Streptococcus gallolyticus.

Animals↗
PubMed1999

A polyphasic approach towards the identification of strains belonging to Lactobacillus acidophilus and related species.

A set of 98 strains belonging to nine species of the Lactobacillus acidophilus rRNA-group have been analysed by SDS-PAGE of cellular proteins, RAPD-PCR and AFLP with fluorescently labeled primers in order to find improved methods for their identification. Strains of the following phenotypically highly similar species were examined: L. acidophilus, L. amylovorus, L. crispatus, L. johnsonii, L. gasseri, L. gallinarum, L. helveticus, L. iners and L. amylolyticus. Although the majority of the species can be differentiated by SDS-PAGE of whole-cell proteins, the latter technique showed poor discrimination between L. gasseri and L. johnsonii strains and between some strains of L. amylovorus and L. gallinarum. However, this study shows that the RAPD-PCR (using at least 3 different primers followed by numerical analysis of the combined patterns) and AFLP are most suitable genomic fingerprinting techniques for the differentiation of all the species listed above, and that databases for identification can be constructed, particularly when commercially available molecular tool-kits are used. The separate species status of the recently described L. amylolyticus and L. iners was fully confirmed.

Bacterial Proteins↗
PubMed1999

Lactobacillus perolens sp. nov., a soft drink spoilage bacterium.

Lactic acid bacteria that are able to spoil soft drinks with low pH comprise a limited number of acidotolerant or acidophilic species of the genera Lactobacillus, Leuconostoc and Weissella. Various Gram-positive rods causing turbidity and off-flavour were isolated from orange lemonades. Physiological and biochemical studies including SDS-PAGE whole-cell protein analysis showed a homogeneous group of organisms. The 16S rRNA gene sequence analysis of two representatives revealed that they formed a phylogenetically distinct line within the genus Lactobacillus. All strains were facultatively heterofermentative, producing L-lactic acid. Based on the data presented a new species L. perolens is proposed. The name refers to the off-flavour caused by high amounts of diacetyl. The type strain of L. perolens is DSM 12744 (LMG 18936). A rRNA targeted oligonucleotide probe was designed that allows a fast and reliable identification of L. perolens.

Bacterial Proteins↗
PubMed1999

Streptococcus pluranimalium sp. nov., from cattle and other animals.

Strains from subclinical mastitis, from the genital tract and tonsils of cattle, from tonsils of a goat and a cat and from the crop and the respiratory tract of canaries were found to constitute a new streptococcal species, for which the name Streptococcus pluranimalium sp. nov. is proposed. Sequencing of 16S rRNA showed that Streptococcus thoraltensis and Streptococcus hyovaginalis were its closest known phylogenetic relatives. The new species showed some phenotypic resemblance to the poorly described species Streptococcus acidominimus, but whole-cell protein analysis and 16S rRNA sequencing revealed that the new species was only distantly related to the type strain of S. acidominimus. Identification of these bacteria, which showed heterogeneous biochemical reaction patterns, was most reliably made by whole-cell protein analysis. Nevertheless, a number of biochemical reactions can be used to differentiate S. pluranimalium from other animal streptococci. Strain LMG 14177T, isolated from mastitic milk of a dairy cow, was designated as the type strain of S. pluranimalium sp. nov.

Animals↗
PubMed1999

Identification of lactic acid bacteria from chili bo, a Malaysian food ingredient.

Ninety-two strains of lactic acid bacteria (LAB) were isolated from a Malaysian food ingredient, chili bo, stored for up to 25 days at 28 degreesC with no benzoic acid (product A) or with 7,000 mg of benzoic acid kg-1 (product B). The strains were divided into eight groups by traditional phenotypic tests. A total of 43 strains were selected for comparison of their sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) whole-cell protein patterns with a SDS-PAGE database of LAB. Isolates from product A were identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus farciminis, Pediococcus acidilactici, Enterococcus faecalis, and Weissella confusa. Five strains belonging to clusters which could not be allocated to existing species by SDS-PAGE were further identified by 16S rRNA sequence comparison. One strain was distantly related to the Lactobacillus casei/Pediococcus group. Two strains were related to Weissella at the genus or species level. Two other strains did not belong to any previously described 16S rRNA group of LAB and occupied an intermediate position between the L. casei/Pediococcus group and the Weissella group and species of Carnobacterium. The latter two strains belong to the cluster of LAB that predominated in product B. The incidence of new species and subspecies of LAB in chili bo indicate the high probability of isolation of new LAB from certain Southeast Asian foods. None of the isolates exhibited bacteriocin activity against L. plantarum ATCC 14917 and LMG 17682.

DNA, Bacterial↗
PubMed1998

Whole-cell protein electrophoretic analysis of viridans streptococci: evidence for heterogeneity among Streptococcus mitis biovars.

One hundred reference strains representing all species belonging to the different phylogenetic lineages of the viridans streptococci were examined by means of one-dimensional whole-organism protein electrophoresis. For most of the species examined, multiple strains characterized by DNA-DNA hybridization were included and, wherever described, representatives of different biochemical variants were analysed. Most species were clearly differentiated. The data support the viewpoint that members of the Streptococcus anginosus group constitute a single species and indicate that Streptococcus mitis biovar 2 is a heterogeneous taxon comprising strains from several streptococcal species.

Bacterial Proteins↗
PubMed1998

Identification of streptococci from Greek Kasseri cheese and description of Streptococcus macedonicus sp. nov.

Taxonomic studies were performed on some Streptococcus-like organisms isolated from naturally fermented Greek Kasseri cheese. By SDS-PAGE analysis of whole-cell proteins the group was found to be quite different from Streptococcus thermophilus. Comparative 16S and 23S rRNA sequence analyses showed that the isolates represent a new species within the genus Streptococcus, where they are most closely related to the Streptococcus bovis cluster. On the basis of these phylogenetic results and some phenotypic differences, a new species, Streptococcus macedonicus, is proposed. The type strain is ACA-DC 206.

Bacterial Proteins↗
PubMed1998

Lactobacillus manihotivorans sp. nov., a new starch-hydrolysing lactic acid bacterium isolated during cassava sour starch fermentation.

Two Lactobacillus strains were isolated from sour cassava starch fermentation. The cells were Gram-positive, catalase-negative, non-spore-forming, non-motile rods. They produced only L(+)lactate and were homofermentative. Growth occurred at pH values of 5.0-7.0 and optimum growth occurred at pH 6.0. Growth was positive at 15 and 45 degrees C. The DNA G + C content was 48.4 +/- 0.2 mol%. Sequence analysis of the 16S rRNA gene revealed that strains OND 32T and YAM 1 clustered with, but were separate from Lactobacillus casei-related taxa. Protein pattern and sequence analyses of the 16S rRNA gene confirmed that the two new isolates represent a new Lactobacillus species, for which the name Lactobacillus manihotivorans is proposed; strain OND 32T is the type strain of this species.

Base Composition↗
PubMed1998

Differentiation between Streptococcus gallolyticus strains of human clinical and veterinary origins and Streptococcus bovis strains from the intestinal tracts of ruminants.

Strains formerly identified as Streptococcus bovis were allotted to two groups by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of whole-cell proteins. Strains from humans with infections, mostly patients with endocarditis, and strains from pigeons with septicemia clustered with the recently described species Streptococcus gallolyticus. The original S. bovis type strain and strains exclusively from ruminants formed the second cluster. The findings indicate that S. gallolyticus is more likely to be involved in human and animal infections than S. bovis. Growth characteristics and several biochemical reactions were found to be useful in the differentiation of S. gallolyticus from S. bovis.

Animals↗