The International Classification of Functioning, Disability and Health (ICF; World Health Organization, 2001) provides an international and interprofessional scientific basis for understanding and ...studying health. The concept of participation plays an important role in the classification and has become a central construct in health care, rehabilitation, and in occupational therapy. The aim of this paper is to provide a critical analysis of the concept of participation in the ICF. As background, the origins and current presentation of the ICF are presented. The use and function of the ICF and the contemporary discussions regarding the classification are reviewed. An occupational perspective on participation in the ICF reveals major shortcomings regarding the subjective experience of meaning and autonomy. Furthermore, the ICF has limitations in capturing different kinds of participation in a single life situation. Following these analyses we discuss the advantages and shortcomings of using the ICF, and how an occupational perspective can contribute to an ongoing discussion about the development of the ICF.
Lactobacillus reuteri, a symbiotic inhabitant of the gastrointestinal tract in humans and animals, is marketed as a probiotic. The ability to adhere to intestinal epithelial cells and mucus is an ...interesting property with regard to probiotic features such as colonization of the gastrointestinal tract and interaction with the host. Here, we present a study performed to elucidate the role of sortase (SrtA), four putative sortase-dependent proteins (SDPs), and one C-terminal membrane-anchored cell surface protein of Lactobacillus reuteri ATCC PTA 6475 in adhesion to Caco-2 cells and mucus in vitro. This included mutagenesis of the genes encoding these proteins and complementation of mutants. A null mutation in hmpref0536_10255 encoding srtA resulted in significantly reduced adhesion to Caco-2 cells and mucus, indicating involvement of SDPs in adhesion. Evaluation of the bacterial adhesion revealed that of the five putative surface protein mutants tested, only a null mutation in the hmpref0536_10633 gene, encoding a putative SDP with an LPxTG motif, resulted in a significant loss of adhesion to both Caco-2 cells and mucus. Complementation with the functional gene on a plasmid restored adhesion to Caco-2 cells. However, complete restoration of adhesion to mucus was not achieved. Overexpression of hmpref0536_10633 in strain ATCC PTA 6475 resulted in an increased adhesion to Caco-2 cells and mucus compared with the WT strain. We conclude from these results that, among the putative surface proteins tested, the protein encoded by hmpref0536_10633 plays a critical role in binding of Lactobacillus reuteri ATCC PTA 6475 to Caco-2 cells and mucus. Based on this, we propose that this LPxTG motif containing protein should be referred to as cell and mucus binding protein A (CmbA).
Lactobacillus reuteri is a symbiont that inhabits the gastrointestinal (GI) tract of mammals, and several strains are used as probiotics. After introduction of probiotic strains in a complex ...ecosystem like the GI tract, keeping track of them is a challenge. The main objectives of this study were to introduce reporter proteins that would enable in vivo and in vitro detection of L. reuteri and increase knowledge about its interactions with the host. We describe for the first time cloning of codon-optimized reporter genes encoding click beetle red luciferase (CBRluc) and red fluorescent protein mCherry in L. reuteri strains ATCC PTA 6475 and R2LC. The plasmid persistence of mCherry-expressing lactobacilli was evaluated by both flow cytometry (FCM) and conventional plate count (PC), and the plasmid loss rates measured by FCM were lower overall than those determined by PC. Neutralization of pH and longer induction duration significantly improved the mCherry signal. The persistency, dose-dependent signal intensity and localization of the recombinant bacteria in the GI tract of mice were studied with an in vivo imaging system (IVIS), which allowed us to detect fluorescence from 6475-CBRluc-mCherry given at a dose of 1×1010 CFU and luminescence signals at doses ranging from 1×105 to 1×1010 CFU. Both 6475-CBRluc-mCherry and R2LC-CBRluc were localized in the colon 1 and 2 h after ingestion, but the majority of the latter were still found in the stomach, possibly reflecting niche specificity for R2LC. Finally, an in vitro experiment showed that mCherry-producing R2LC adhered efficiently to the intra cellular junctions of cultured IPEC-J2 cells. In conclusion, the two reporter genes CBRluc and mCherry were shown to be suitable markers for biophotonic imaging (BPI) of L. reuteri and may provide useful tools for future studies of in vivo and in vitro interactions between the bacteria and the host.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Bacterial extracellular membrane vesicles (MV) are potent mediators of microbe-host signals, and they are not only important in host-pathogen interactions but also for the interactions between ...mutualistic bacteria and their hosts. Studies of MV derived from probiotics could enhance the understanding of these universal signal entities, and here we have studied MV derived from
Limosilactobacillus reuteri
DSM 17938 and BG-R46. The production of MV increased with cultivation time and after oxygen stress. Mass spectrometry-based proteomics analyses revealed that the MV carried a large number of bacterial cell surface proteins, several predicted to be involved in host-bacteria interactions. A 5′-nucleotidase, which catalyze the conversion of AMP into the signal molecule adenosine, was one of these and analysis of enzymatic activity showed that
L. reuteri
BG-R46 derived MV exhibited the highest activity. We also detected the TLR2 activator lipoteichoic acid on the MV. In models for host interactions, we first observed that
L. reuteri
MV were internalized by Caco-2/HT29-MTX epithelial cells, and in a dose-dependent manner decreased the leakage caused by enterotoxigenic
Escherichia coli
by up to 65%. Furthermore, the MV upregulated IL-1β and IL-6 from peripheral blood mononuclear cells (PBMC), but also dampened IFN-γ and TNF-α responses in PBMC challenged with
Staphylococcus aureus
. Finally, we showed that MV from the
L. reuteri
strains have an antagonistic effect on the pain receptor transient receptor potential vanilloid 1 in a model with primary dorsal root ganglion cells from rats. In summary, we have shown that these mobile nanometer scale MV reproduce several biological effects of
L. reuteri
cells and that the production parameters and selection of strain have an impact on the activity of the MV. This could potentially provide key information for development of innovative and more efficient probiotic products.
Large amounts of food and feed are lost every year due to spoilage by moulds and yeasts. Biopreservation, i.e. the use of microorganisms as preservatives instead of chemicals, has gained increased ...interest. Lactic acid bacteria and propionibacteria might be particularly useful due to their important role in many food fermentations. Knowledge of the antifungal effects of the organic acids produced by these bacteria is necessary to understand their inhibitory activity. We evaluated the antifungal activity of the type strains of five dairy propionibacteria,
Propionibacterium acidipropionici,
P. jensenii,
P. thoenii,
P. freudenreichii subsp.
freudenreichii and
P. freudenreichii subsp.
shermanii against eight food- and feedborne moulds and yeasts. A dual culture system assayed the inhibitory activity on three different agar media, sodium lactate (SL), de Man Rogosa Sharp (MRS) and MRS without acetate (MRS-ac). The amounts of organic acids produced during growth of propionibacteria in liquid SL, MRS and MRS-ac were also determined. The minimal inhibitory concentration (MIC) values of propionic, acetic and lactic acid were established for all fungi at pH 3, 5 and 7. Propionic acid, followed by acetic acid, was the most potent antifungal acid. Inhibition at pH 7 generally required concentrations above 500 mM for all three acids, at pH 5 the MIC values for propionic and acetic acids were 20–120 mM and above 500 mM for lactic acid. At pH 3, the MIC values were, with one exception, below 10 mM for both propionic and acetic acid and above 160 mM for lactic acid. The yeast
Pichia anomala was the fungus most resistant to organic acids. The propionibacteria exhibited a pronounced species variation in antifungal activity on MRS (±acetate) agar, with
P. thoenii being the most potent. Four of the five propionibacteria species produced more propionic and acetic acid in liquid SL medium than in MRS (±acetate) broth. However, when SL agar was used as the growth medium, none of the propionibacteria inhibited fungal growth.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
To be able to function as a probiotic, bacteria have to survive the passage through the gastrointestinal tract. We have examined survival and gene expression of Lactobacillus reuteri ATCC 55730 after ...a sudden shift in environmental acidity to a pH close to the conditions in the human stomach. More than 80% of the L. reuteri cells survived at pH 2.7 for 1 h. A genomewide expression analysis experiment using microarrays displayed 72 differentially expressed genes at this pH. The early response to severe acid shock in L. reuteri differed from long-term acid adaptation to milder acid stress studied in other lactic acid bacteria. The genes induced included the following: clpL, genes putatively involved in alterations of the cell membrane and the cell wall; genes encoding transcriptional regulators; phage genes; and genes of unknown function. Two genes, clpL, encoding an ATPase with chaperone activity, and lr1516, encoding a putative esterase, were selected for mutation analyses. The mutants were significantly more sensitive to acid than the wild type was. Thus, these genes could contribute to the survival of L. reuteri in the gastrointestinal tract.
Abstract
Segmented filamentous bacteria (SFB) are inhabitants of the small intestine of various animals, where they can be detected microscopically due to their specific morphology and intimate ...association with the intestinal epithelium. SFB colonize the distal part of the small intestine in a host-specific manner and affects important functions of the immune system, such as the induction of secretory IgA production and regulation of T-cell maturation. Considering the influences SFB have on immune functions, they could be regarded as a key species in host–microbial interactions of the gastrointestinal tract. Although these influences might be executed by other microorganisms, a human-adapted variant of SFB is not unlikely. In this study, ileostomy samples from 10 human subjects were screened with PCR, using primers derived from sequences of SFB from rat and mouse. PCR products were obtained from samples taken from one individual at two time points. Sequencing revealed the presence of a 16S rRNA gene with high similarity (98%) to the corresponding genes from SFB of mouse and rat origin, thus indicating the presence of a human variant of SFB. The findings presented in this study will hopefully encourage research to elucidate whether this intriguing organism is a persistent member of the normal human microbiota.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
1 Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden
2 Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
...Correspondence Stefan Roos stefan.roos{at}mikrob.slu.se
In an attempt to study the composition of the Lactobacillus flora from mucosa of human stomach, 16S rRNA gene sequences of 129 isolates were analysed. For 15 of these, the results differed significantly from known sequences, and additional tests were performed to determine whether these isolates represented as yet unrecognized species. Phenotypic and genetic characteristics revealed that these isolates represented four novel Lactobacillus species. Two belong to the Lactobacillus reuteri and the other two to the Lactobacillus delbrueckii subgroup of Lactobacillus . The names Lactobacillus gastricus sp. nov., Lactobacillus antri sp. nov., Lactobacillus kalixensis sp. nov. and Lactobacillus ultunensis sp. nov. are proposed, with the respective type strains Kx156A7 T (=LMG 22113 T =DSM 16045 T =CCUG 48454 T ), Kx146A4 T (=LMG 22111 T =DSM 16041 T =CCUG 48456 T ), Kx127A2 T (=LMG 22115 T =DSM 16043 T =CCUG 48459 T ) and Kx146C1 T (=LMG 22117 T =DSM 16047 T =CCUG 48460 T ).
Published online ahead of print on 20 August 2004 as DOI 10.1099/ijs.0.63083-0.
The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of Lactobacillus gastricus Kx156A7 T , Lactobacillus antri Kx146A4 T , Lactobacillus kalixensis Kx127A2 T and Lactobacillus ultunensis Kx146C1 T are AY253658 , AY253659 , AY253657 and AY253660 , respectively.
Daily routine ventilator-filter exchange interrupts the integrity of the ventilator circuit. We hypothesized that this might reduce positive airway pressure in mechanically ventilated ICU patients, ...inducing alveolar collapse and causing impaired oxygenation and compliance of the respiratory system.
We studied 40 consecutive ICU subjects (P(aO2)/F(IO2) ratio ≤ 300 mm Hg), mechanically ventilated with pressure-regulated volume control or pressure support and PEEP ≥ 5 cm H2O. Before the filter exchange, (baseline) tidal volume, breathing frequency, end-inspiratory plateau pressure, and PEEP were recorded. Compliance of the respiratory system was calculated; F(IO2), blood pressure, and pulse rate were registered; and P(aO2), P(aCO2), pH, and base excess were measured. Measurements were repeated 15 and 60 min after the filter exchange. In addition, a bench test was performed with a precision test lung with similar compliance and resistance as in the clinical study.
The exchange of the filter took 3.5 ± 1.2 s (mean ± SD). There was no significant change in P(aO2) (89 ± 16 mm Hg at baseline vs 86 ± 16 mm Hg at 15 min and 88 ± 18 mm Hg at 60 min, P = .24) or in compliance of the respiratory system (41 ± 11 mL/cm H2O at baseline vs 40 ± 12 mL/cm H2O at 15 min and 40 ± 12 mL/cm H2O at 60 min, P = .32). The bench study showed that auto-triggering by the ventilator when disconnecting from the expiratory circuit kept the tracheal pressure above PEEP for at least 3 s with pressure controlled ventilation.
This study showed that a short disconnection of the expiratory ventilator circuit from the ventilator during filter exchange was not associated with any significant deterioration in lung function 15 and 60 min later. This result may be explained by auto-triggering of the ventilator with high inspiratory flows during the filter exchange, maintaining airway pressure.
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