Symbiosis between host and microorganisms: neonatal colonization.
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Actinomycetaceae↗
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Alveolar phospholipids of 17-day-old pigs exposed to microorganisms of nonpulmonic origin.
Alveolar lining material was obtained from gnotobiotic pigs; gnotobiotic pigs exposed to aerobes, anaerobes, or mixtures of both microorganisms; and conventional farm-raised pigs. Alveolar lining material concentrations of phosphatidylcholine, sphingomyelin, phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, and lysolecithin were determined. Seventy-four pigs were allotted to the following groups: 1--gnotobiotes (n = 13), 2--gnotobiotes with aerobes (n = 6), 3--gnotobiotes with anaerobes (n = 31), 4--gnotobiotes with anaerobes and aerobes (n = 2), 5--gnotobiotes with facultative anaerobes (n = 9), and 6--conventionally farm-farrowed (n = 13). The conventionally raised pigs had lysolecithin, sphingomyelin, and phosphatidylinositol concentrations that were significantly different from those of all other groups of pigs. Phosphatidylethanolamine was significantly decreased in group 6 pigs when compared with that in all other groups. There were also statistically significant differences between the gnotobiotic (group 1) and the exposed gnotobiotic (groups 2, 3, 4, 5) pigs, although the differences were less pronounced. Since intestinal microbes produce alveolar lining material phospholipid differences, studies need to be concerned with phospholipid changes that occur after exposure to lung-specific microorganisms and with physiologic changes in lung function associated with the phospholipid changes.
Animals↗
[Adhesion of lactic acid bacteria to epithelium of different cavities of the human organism].
During investigation of adhesive properties of lactic acid bacteria it was found out that 11 strains adhered to buccal intestinal and vaginal epithelium of human. The highest adhesive activity was detected in enterococci (adhesive index 7.75-14.26), lower one--in streptococci (6.40-9.16). In lactobacilli adhesive properties manifested in different ways: Lactobacillus acidophilus strains adhered more often to buccal epithelium (2.58-4.60) and rarely--to intestinal and vaginal. L. plantarum manifested high adhesive activity (8.03 -9.69) to buccal epithelium and lower one--to the rest of epithelium types. Monosaccharide composition of glycocalix of 6 strains of lactic acid bacteria was studied to understand the adhesion mechanism. It was shown that surface structures of this microorganism interact with plant lectins, specific to certain monosaccharides.
Bacterial Adhesion↗
[Simulation of intestinal microbial overgrowth by continuous culture].
By the aid of continuous flow culture of microbial populations it is possible to answer specific micro_ecological questions even under anaerobic conditions. We present some findings from a continuous flow model of human duodenal juice with microbial overgrowth. Germ counts and species were reproducible in a steady state over several days. Metabolic activity was very high. For example, this model allows the in vitro study of therapeutic possibilities against overgrowth syndrome, microbial fermentation of food, metabolism of drugs and the growth of microorganisms on surfaces in gastrointestinal tract.
Bacteria↗
B cell recruitment and selection in mouse GALT germinal centers.
In conventionally reared mice germinal centers (GCs) are chronically induced in Peyer's patches (PP), mesenteric lymph node (MLN), and isolated lymphoid follicles (ILF) of gut-associated lymphoid tissues (GALT), as a result of continuous B cell stimulation by commensal bacteria. It is generally thought that BCR-mediated antigen recognition controls the recruitment and thus selection of B cells within GALT GCs. However, recent results challenge this view and suggest that engagement of innate immune receptors by microbial antigens promotes B cell recruitment to, and maintenance within, the GC, irrespective of BCR specificity. We propose a scenario in which microbial determinants presented by follicular dendritic cells (FDCs) to innate receptors on B cells within the GC support the survival and concomitant expansion of somatically mutated, IgA-class-switched B cell clones expressing a variety of BCR specificities. From this pool, B cell mutants recognizing gut-derived antigens through their BCR are either, in GCs, drawn into the process of affinity maturation, or, in the lamina propria (LP) of the gut, locally selected to differentiate into plasmablasts, thus contributing to the continuous production of IgA antibodies required for an efficient protection against commensal and pathogenic microorganisms.
Animals↗
The F4 fimbrial antigen of Escherichia coli and its receptors.
F4 or K88 fimbriae are long filamentous polymeric surface proteins of enterotoxigenic Escherichia coli (ETEC), consisting of so-called major (FaeG) and minor (FaeF, FaeH, FaeC, and probably FaeI) subunits. Several serotypes of F4 have been described, namely F4ab, F4ac, and F4ad. The F4 fimbriae allow the microorganisms to adhere to F4-specific receptors present on brush borders of villous enterocytes and consequently to colonize the small intestine. Such ETEC infections are responsible for diarrhea and mortality in neonatal and recently weaned pigs. In this review emphasis is put on the morphology, genetic configuration, and biosynthesis of F4 fimbriae. Furthermore, the localization of the different a, b, c, and d epitopes, and the localization of the receptor binding site on the FaeG major subunit of F4 get ample attention. Subsequently, the F4-specific receptors are discussed. When the three variants of F4 (F4ab, F4ac, and F4ad) are considered, six porcine phenotypes can be distinguished with regard to the brush border adhesiveness: phenotype A binds all three variants, phenotype B binds F4ab and F4ac, phenotype C binds F4ab and F4ad, phenotype D binds F4ad, phenotype E binds none of the variants, and phenotype F binds F4ab. The following receptor model is described: receptor bcd is found in phenotype A pigs, receptor bc is found in phenotype A and B pigs, receptor d is found in phenotype C and D pigs, and receptor b is found in phenotype F pigs. Furthermore, the characterization of the different receptors is described in which the bcd receptor is proposed as collection of glycoproteins with molecular masses ranging from 45 to 70 kDa, the bc receptor as two glycoproteins with molecular masses of 210 an 240 kDa, respectively, the b receptor as a glycoprotein of 74 kDa, and the d receptor as a glycosphingolipid with unknown molecular mass. Finally, the importance of F4 fimbriae and their receptors in the study of mucosal immunity in pigs is discussed.
Animals↗
Food pathogens as the most common cause of bacterial food poisoning.
The aim of the paper was to characterize the food borne microorganisms, which are the most common causes of bacterial food poisonings in humans. Furthermore, the dietary recommendations in acute gastro-intestinal disorders were presented.
Acute Disease↗
Structure and function of intestinal M cells.
M cells are structurally distinctive, uniquely permeable epithelial cells found only overlying the domes of mucosal lymphoid follicles. Antigenic macromolecules and some viruses, bacteria, and protozoa enter their apical surface by endocytosis or phagocytosis. These substances traverse the M-cell cytoplasm by transcytosis, breaching the epithelial barrier, and then interact with the subepithelial immunocompetent cells to initiate mucosal and systemic immune responses. The M cell serves as a portal of entry for selected pathogens that cause disease locally in the wall of the intestine or, following dissemination, at distant sites. The mechanisms that regulate adherence to and penetration of M cells by macromolecules and microorganisms are not known, but selective binding of secretory IgA to the luminal surface may be important. Whether M cells simply serve a sieving function and always transport substances unchanged across the epithelial barrier or whether they also sort and process antigens they endocytose and present them to adjacent lymphoid cells requires further study.
Animals↗
Antigen sampling by epithelial tissues: implication for vaccine design.
Mucosal surfaces of the respiratory, digestive and urogenital tracts are covered by a specialized epithelium which constitutes an efficient physical barrier against environmental pathogens. These surfaces differ greatly in their cellular organisation and in antigen sampling. In stratified epithelia, professional antigen-presenting cells, the dendritic cells or Langerhans cells, are intimately associated with the epithelial barrier and take up samples of foreign material from the external environment which they transport to local or distant organized lymphoid tissues. In simple epithelia highly specialised cells, the so-called M cells, sample foreign material and microorganisms and deliver them by transepithelial transport from the lumen to the underlying organized lymphoid tissue (MALT). The interaction of lymphocytes with the follicle-associated epithelium (FAE) is responsible for the loss of digestive functions and the acquisition of transepithelial transport activity. The three way interaction of epithelium, lymphoid cells, and microorganisms seen in the FAE which controls the formation of MALT provides a dramatic demonstration of the phenotypic plasticity of the intestinal epithelium and probably of all simple epithelia. We have shown that all mucosal surfaces, covered by stratified or simple epithelia are able to sample and transport live recombinant bacterial vaccines, which elicit systemic and local immune responses against the carrier and the foreign antigen. In gut and nasal-associated lymphoid tissue, Salmonella are taken up by dendritic cells which form a dense cellular network in the dome regions of MALT. Targeting bacterial vaccine candidates to dendritic or M cells is likely to facilitate their sampling by epithelial tissues and to contribute to strong mucosal and systemic immune responses.
Animals↗
Adhesion of bacteria to the human small-intestinal mucosa. A scanning electron microscopic study.
During the period 1 January 1980 to 30 June 1986, a total of 543 small-intestinal biopsy specimens from adults with gastrointestinal symptoms were available for routine analysis with correlated scanning electron microscopy and light microscopy. Adhesion of microorganisms was found in 77 biopsy specimens. Microorganisms in 64 specimens were classified as bacteria, in 10 as microfungi and in 4 as protozoa, including 1 specimen with both bacteria and microfungi. The structural types of bacteria found were morphologically cocciform, 8; short rod-shaped, 14; and long rod-shaped, 43. One specimen demonstrated adhesion of two structural types of bacteria. Bacteria were found in specimens from all age groups in roughly equal frequency. There was no difference in villus structure when comparing specimens from the groups with and without adhering bacteria, whereas ultrastructural alteration--that is, thinning of glycocalyx layer--was significantly more frequent in the group with bacteria. Moreover, within the group of specimens with bacteria the presence of long rod-shaped bacteria was associated with both damage of villus structure and deviation of cell surface ultrastructure. An increased amount of neutrophil granulocytes as an indicator of acute inflammation was found in 6 of 51 specimens with bacterial adhesion but in none of a matched reference material. In contrast, the amount of plasma cells and lymphocytes in the lamina propria and the amount of intraepithelial lymphocytes did not differ.
Adolescent↗
Role of microecology in chronic inflammatory bowel diseases.
Inflammatory bowel diseases (IBD) are chronic conditions of unknown etiology. Current therapy mitigates the severity of acute bouts of mucosal inflammation but an eradication therapy is lacking. Growing incidence of IBD is associated with social development. Epidemiology suggests a relationship between the establishment of the individual gut flora and the risk of developing IBD. Patients show an impaired tolerance towards commensal bacteria of the resident flora. Unrestrained activation of the intestinal immune system against some commensal bacteria appears to be responsible for the characteristic relapsing course of these diseases. Wide-spectrum antibiotic therapy reduces bacterial load and mitigates intestinal inflammation in human IBD and in animal models. Current research aims at the identification of probiotics for bacterial antagonism therapies. Probiotics are living microorganisms which upon ingestion in certain numbers exert health benefits beyond inherent basic nutrition. Colonization with a Lactobacillus reuteri strain can prevent the development of colitis in genetically susceptible mice. Other studies have used a bacterium genetically engineered to secrete the antiinflammatory cytokine IL-10 and demonstrated a therapeutic effect in animal models of colitis. Moreover, some probiotics may naturally exhibit antiinflammatory properties when interacting with the human gut mucosa. Prebiotics such as inulin have also been shown to prevent colonic inflammation in animal models. Preliminary clinical trials with probiotics in IBD are encouraging. Probiotics offer a valuable tool for the prevention and control of inflammatory bowel diseases.
Animals↗
[Influence of the food products, enriched with pectin, on properties of potentially patogenic representatives of the microflora of the large intenstine].
The treatment method of disbios suffered by patients with syndrome of irritated intestines with constipations was under research. The method was based on introduction of sour-milk beverage with addition of beet pectin in a dietary intake. The comparison product was kefir. The following developments were detected against the positive dynamics of clinical symptoms: improvement of microbiocenosis structure, reduction of potentially pathogenic germs, inhibition of pathogenic properties of enterotoxigenic Staphylococcus aureus. Comparison group results showed lower clinical efficiency and poorer effect of dietary treatment on large gut microorganisms, contents of enterotoxigenic S. aureus remained unchanged. Introduction of sour-milk beverage with addition of alimentary fibre in a dietary intake of patients suffering the syndrome of irritated intestines with constipations was found expedient.
Adult↗
Supplementation with effective microorganisms in earthen ponds affects common carp growth and abundance of specific bacterial families.
BACKGROUND: Effective microorganisms are increasingly explored in aquaculture to improve fish health and growth without leaving harmful residues. However, their efficacy in real-world pond environments remains poorly understood. Here, we conducted a 103-day field experiment to assess the effects of supplementation with two effective commercial microorganism products on the microbial communities and growth performance of common carp (Cyprinus carpio). BACKGROUND: Effective microorganisms were added to the feed and directly to the pond water. Microbial diversity was analysed via 16 S rRNA and whole-genome shotgun sequencing across three environments: water (three time points), sediment (two time points), and fish intestine (one time point) from 25 experimental ponds. Bioinformatics processing was performed using the QIIME2 and MG-TK pipelines with taxonomic classification based on the SILVA database. The results showed that although supplemented bacterial families did not establish significantly in pond environments, fish exposed to specific effective microorganism treatments showed improved growth metrics. CONCLUSIONS: These findings suggest that effective microorganisms can increase carp growth in aquaculture without significantly altering the resident microbial communities, suggesting a promising residue-free alternative to traditional additives in aquaculture.
Animals↗
Probiotic and milk technological properties of Lactobacillus brevis.
Two Lactobacillus brevis strains ATCC 8287 and ATCC 14869(T), were evaluated for their applicability as putative probiotics in dairy products. The strains expressed good in vitro adherence to human Caco-2 and Intestine 407 cells and tolerated well low pH, bile acids and pancreatic fluid under in vitro conditions. In antimicrobial activity assays, strain ATCC 8287 showed inhibitory properties toward selected potential harmful microorganisms, particularly against Bacillus cereus. Both L. brevis strains were resistant to vancomycin, which is typical for the genus Lactobacillus. The L. brevis strains were not able to acidify milk to yoghurt but were suitable as supplement strains in yoghurts. This was shown by producing a set of yoghurt products and analysing their rheological and sensory properties during a cold storage period of 28 days. Survival of the strains through human intestine was examined in 1-week feeding trials. Despite its human origin, L. brevis ATCC 14869(T) could not survive through the gastrointestinal (GI) tract, whereas L. brevis ATCC 8287 was detected in the faecal samples taken during and immediately after ingestion of the strain. In conclusion, L. brevis ATCC 8287 is a promising candidate as a probiotic supplement in dairy products.
Animals↗
Cytochemistry, morphogenesis, and tentative identification of myecetomal microorganisms of Sitophilus granarius L. (Coleoptera).
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Bacteria↗
[Use of India ink for the purpose of the specific detection of pathogenic microorganisms in histological preparations].
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Animals↗
[Participitation of microorganisms in the digestive metabolism of swine. 1. Slaughter pigs].
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Animals↗
Tacrolimus (FK506) and cyclosporine reduce the uptake and transport of particles into rabbit Peyer's patches.
Tacrolimus (FK) and cyclosporine (Cs) are potent immunosuppressants that effectively prevent the rejection of transplanted organs including liver and small intestine. Our study examined the effects of these immunosuppressants on Peyer's patches, which play an important role in mucosal immune response through uptake and transport of enteric microorganisms and macromolecules in the gut-associated lymphoid tissues. After administration of FK and Cs, we assessed changes in lymphoid follicle structure and quantified the uptake and transport of particles in the follicle associated epithelium (FAE) including M cells, using fluorescent latex microspheres in rabbit Peyer's patches. Rabbits, five in each group, received oral administration of FK (3.2 mg/kg), Cs (10 mg/kg), or phosphate-buffered saline daily for 7 days. After 2 days of withdrawal, rabbits were anesthetized, and received injections with 2 ml of the suspension of 0.5-microm fluorescent microspheres (1010/ml) into ligated intestinal segments containing Peyer's patches. After 2 hr of gentle agitation, segments were removed, rinsed, fixed with periodate-lysine-2% paraformaldehyde, frozen, and sections were stained with fluorescent phalloidin to label brush border actin filaments. The size of the lymphoid follicles in each group was measured under a light microscope. The number of microspheres in follicles was assessed in graphically defined areas of follicles from each group. In addition, immunohistochemical analysis of CD43 and MHC-II positive cells in FAE of lymphoid follicles of each group was performed. FK and Cs significantly reduced the height of lymphoid domes and the height and width of follicles, as compared to those of controls. In both FK and Cs groups, the numbers of microspheres that adhered, were taken up and were transported into lymphoid follicles were smaller than in controls, indicating that their movement rates into deep layers were markedly reduced. Furthermore, FK and Cs reduced the mean numbers of CD43 and MHC-II positive cells in FAE per unit area (mm2) as compared with controls. These findings suggest that FK and Cs may produce immunosuppressive effects, at least in part, through reduction of the uptake and transport of particles into Peyer's patches, and by reduction of the number of immunoreactive cells in FAE of Peyer's patches.
Animals↗