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PubMedDate not supplied

Bioactive peptides encrypted in milk proteins: proteolytic activation and thropho-functional properties.

The bioactivities of peptides encrypted in major milk proteins are latent until released and activated by enzymatic proteolysis, e.g. during gastrointestinal digestion or food processing. The proteolytic system of lactic acid bacteria can contribute to the liberation of bioactive peptides. In vitro, the purified cell wall proteinase of Lactococcus lactis was shown to liberate oligopeptides from beta- and alpha-caseins which contain amino acid sequences present in casomorphins, casokinines, and immunopeptides. The further degradation of these peptides by endopeptidases and exopeptidases of lactic acid bacteria could lead to the liberation of bioactive peptides in fermented milk products. However, the sequences of practically all known biologically active peptides can also be cleaved by peptidases from lactic acid bacteria. Activated peptides are potential modulators of various regulatory processes in the body: Opioid peptides are opioid receptor ligands which can modulate absorption processes in the intestinal tract, angiotensin-I-converting enzyme (ACE)-inhibitory peptides are hemodynamic regulators and exert an antihypertensive effect, immunomodulating casein peptides stimulate the activities of cells of the immune system, antimicrobial peptides kill sensitive microorganisms, antithrombotic peptides inhibit aggregation of platelets and caseinophosphopeptides may function as carriers for different minerals, especially calcium. Bioactive peptides can interact with target sites at the luminal side of the intestinal tract. Furthermore, they can be absorbed and then reach peripheral organs. Food-derived bioactive peptides are claimed to be health enhancing components which can be used for functional food and pharmaceutical preparations.

Amino Acid Sequence↗
PubMed1975

[Possible role of microbial factors in the pathogenesis of ulcerative colitis].

Electron-microscopy studies of the epithelium of the large intestine mucosa in patients with nonspecific ulcerative colitis (biopsy material) and that of rats with experimental allergic ulcerative colitis revealed the penetration of microorganisms into goblet cells of the experimental animals at various stages of mucigenoformation. The bioptic material showed no such pictures. It appears that factor of immunization played a certain role in the realization of the influence of microorganisms on pathogenesis of ulcerative colitis. The structural feature of the development of glycocalix are described on the basis of clinical and experimental material.

Animals↗
PubMed2006

Effect of dalbavancin on the normal intestinal microflora.

OBJECTIVES: Dalbavancin is a new lipoglycopeptide antibiotic active in vitro against most Gram-positive bacteria. It is administered parenterally as a weekly regimen, is eliminated both in urine and faeces, and has t(1/2) in plasma of 8.5 days. Investigating the impact of antibiotics on endogenous microflora is important since alteration of the balance may facilitate colonization by new potentially pathogenic strains or enable microorganisms in the normal flora to develop resistance. The purpose of the present study was to investigate the effect of administration of dalbavancin on the intestinal flora of healthy subjects. METHODS: Six women and six men, 18-40 years, received a single 30 min intravenous infusion of 1 g dalbavancin. Plasma and faeces were collected over several weeks for determination of dalbavancin concentration and analysis of faecal flora. Faecal specimens were cultured on non-selective and selective media. Different colony types were counted, isolated in pure culture and identified to genus level. All new colonizing bacteria were tested for susceptibility to dalbavancin. RESULTS: Plasma dalbavancin concentrations at 2, 21 and 60 days after administration were 35.8-208.7, 3.9-22.1 and 0.5-2.9 mg/L, respectively. The faecal concentrations of dalbavancin were 6.8-73.4 mg/kg on day 5 and 7.4-26.4 mg/kg on day 14. Dalbavancin was not detectable in faeces on day 60. There was some impact on numbers of enterococci and Escherichia coli and no changes in numbers of lactobacilli, clostridia and bacteroides. No Clostridium difficile strains were recovered. No new colonizing aerobic and anaerobic bacteria resistant to dalbavancin were found. CONCLUSIONS: Dalbavancin has no major ecological effect on the human normal intestinal microflora.

Adolescent↗
PubMed2005

Arsenic occurrence and species in near-shore macroalgae-feeding marine animals.

This study was undertaken to improve the understanding of arsenic species and their pathways of formation in marine animals: fish (Odax cyanomelas), abalone (Haliotis rubra), and sea urchins (Heliocidaris erythrogramma and Centrostephanus rodgersii) that are directly exposed through their diets to dimethyl arsenoriboses in macroalgae (Phyllospora comosa and Halopteris platycena). The identification of dimethyl arsenoriboses (phosphate, sulfonate, and glycerol) in both dominant macroalgae species, and especially digestive tissues of marine animals that consume them, suggests these arsenic species, are to some degree accumulated directly from their diets without degradation or conversion. An unknown arsenic species in H. rubra intestinal tissue was identified using tandem mass spectrometry as 2',3'-dihydroxypropyl 5-deoxy-5-trimethyl arsonioriboside (trimethyl glycerol arsenoribose). The concentration of trimethyl glycerol arsenoribose in H. rubra intestinal tissue was estimated to account for 28% (5.0 microg g(-1) dry mass) of the methanol-water-soluble arsenic fraction. The presence of a trimethyl glycerol arsenoribose in marine animal tissues may be due to microbial-mediated processes that promote the reduction and methylation of dimethyl arsenoriboses released during the breakdown of macroalgae in their diets. Arsenobetaine formation may then occur in the lumen of the digestive tract (i.e., mediated by microorganisms) or in the liver catalyzed by enzymes. The identification of a large amount of trimethyl glycerol arsenoribose in H. rubra intestinal tissue suggests this species is a main constituent in the pathway for arsenic in this marine animal.

Animals↗
PubMed1998

[Intestinal parasitic infections and leishmaniasis in patients with HIV infection].

Intestinal parasite infections are very frequent in HIV patients with severe immunodeficiency (CD4 < 100/mm3) causing chronic diarrhea and malabsorption in the majority of cases. The most frequent microorganisms are microsporidia and Cryptosporidium parvum while Cyclospora cayetanensis and Isospora belli are more prevalent in subtropical and tropical areas and rare in industrialized areas. The diagnosis can be obtained by stool examination (differences in size and form of cysts), although microsporidia is frequently demonstrated by intestinal biopsy and/or duodenal aspirate. The treatment with cotrimoxazole for C. cayetanensis and I. belli is very effective and does not present any problems in the acute phase, however, due to a high percentage of relapses the treatment must be maintained while the patient is in a severe immunodeficiency state. E. intestinalis usually responds satisfactorily to albendazole while E. bieneusi is resistant to some drugs except in some cases (albendazole, atovaquone ad fumagillin). C parvum is also resistant to most medicaments but shows an adequate or partial clinical: response to paramomicine (< 50%). When there is no response, it is advised to administer octreotide since in half the cases the response is positive either total or partial. Nowadays with the use of protease inhibitors in the antiretroviral treatment a decrease in the incidence of these infections has been observed (microsporidia and C. parvum) even in the stools samples taken from the patients who had them before. As primary prophylaxis for C. parvum, it is better to avoid been exposed to the microorganism taking into account the 1997 preventive measures recommended by the USPHS/IDSA Prevention of Opportunistic Infections Working Group. The coinfection Leishmania-HIV is frequent in the mediterranean area. The most common specie is L. infantum. The incidence is most frequent in immunosuppressed patients (CD4 < 200 mm3) and in parenteral drug addicts. The symptomatology is similar to the one from immunocompetent patients, although in some cases it appears to be subclinical. A chronic development with relapses is frequent. The most effective diagnostic method for the finding of the parasites is thru bone marrow puncture and the culture in Novy-McNeal-Nicolle (NNN) medium. Serological tests have a low sensibility and the PCR is useful in asymptomatic cases, for therapeutical control and in relapses. The treatment is similar to that of immunocompetent patients, using primarily antimonials or amphotericine B (standard or lipid or liposomal forms). Relapses are very frequent, therefore, it is important to perform a secondary prophylaxis. However, no treatment has been completely effective. Mortality rate is high (approximately 25%) during the first month after diagnosis. This fact may be related to the severe immunodeficiency state and/or to the toxicity of the drugs used. The main priority for the future is to find a first line treatment with higher efficacy, decrease in relapses and a lower toxicity.

AIDS-Related Opportunistic Infections↗
PubMed1997

A morphological study of the enteric mucosal epithelium in the streptozotocin-diabetic mouse.

In the acutely diabetic rat, the polyphagia-induced increase in the weight of the small intestine is associated with reported increases in mucosal mass. Whereas, some of the individual mucosal components in the rat have been studied, comparable information for the acutely streptozotocin-diabetic mouse is lacking. A detailed morphological comparison of the epithelium of the small intestinal mucosa in control and untreated streptozotocin-diabetic mice was therefore undertaken. Samples from three small intestinal sites were examined by light and scanning electron microscopy and quantitative data obtained from histological sections. Although the morphological appearance of the small intestine in acutely diabetic mice was similar in many respects to literature accounts for the diabetic rat, infestation with filamentous microorganisms was present in the jejunum and ileum. The quantitative data showed that these sites also contained distorted villi, fewer crypt profiles, more goblet and Paneth cell profiles and a smaller epithelial volume in comparison to controls. These findings may represent differences between the rat and mouse models of streptozotocin-induced diabetes mellitus.

Animals↗
PubMed1975

[Effect of levomycetin on the microflora artificially introduced into the intestines of gnotobiotic chicks].

Levomycetin effect on the microflora introduced into the intestine of abiotic chickens was studied. Levomycetin in a dose of 4 mg perosone chicken for 5 days provided a decrease in the number of Bifidobacteria, Lactobacteria, Escherichia and Enterococci by 100 to 10000 times and an increase in the number of Candida or disbacteriosis in the intestine. The highest effect was observed with respect to multiplication of Lactobacteria. This impaired the ecological quantitative ratio between the microorganisms. Re-establishment of the microbial biocenosis after discontinuation of levomycetin use was not complete. Repeated disbacteriosis in the gastrointestinal tract of the test-chickens was registered on the 16th day.

Actinomycetaceae↗
PubMed1989

Septicemia in adults: II. Factors in prognosis.

Over the period of 2 months between October and November, 1987, 190 episodes of septicemia in adults were monitored at Veterans General Hospital-Taipei. The most common causative microorganisms were Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus. The most frequent sources of infection came from intra-abdominal (gastro-intestinal as well as hepato-biliary), urinary and respiratory tract. Its overall mortality was 34.7%. Factors associated with a higher mortality from septicemia were old age, rapidly fatal underlying disease, hospital acquired infection, hypothermia, hypotension/shock, high-risk source of infection (from respiratory tract, skin/soft tissue, surgical wound or other unknown source), high-risk microorganisms (Candida species, Ps. aeruginosa or K. Pneumoniae) and inappropriate antimicrobial therapy. Identification of these factors may help early correction of reversible factors and improve its prognosis.

Adult↗
PubMed2004

Recognition of commensal microflora by toll-like receptors is required for intestinal homeostasis.

Toll-like receptors (TLRs) play a crucial role in host defense against microbial infection. The microbial ligands recognized by TLRs are not unique to pathogens, however, and are produced by both pathogenic and commensal microorganisms. It is thought that an inflammatory response to commensal bacteria is avoided due to sequestration of microflora by surface epithelia. Here, we show that commensal bacteria are recognized by TLRs under normal steady-state conditions, and this interaction plays a crucial role in the maintenance of intestinal epithelial homeostasis. Furthermore, we find that activation of TLRs by commensal microflora is critical for the protection against gut injury and associated mortality. These findings reveal a novel function of TLRs-control of intestinal epithelial homeostasis and protection from injury-and provide a new perspective on the evolution of host-microbial interactions.

Adaptor Proteins, Signal Transducing↗
PubMed1993

Lactobacilli and the normal human anaerobic microflora.

The normal human microflora is a complex and usually stable ecosystem. The intestinal microflora is important to the host with regard to many metabolic functions and in resistance to bacterial infections. Administration of antimicrobial agents may disrupt the normal microflora, leading to a decrease in colonization resistance and alterations in metabolic activities of the intestinal bacteria. Antimicrobial therapy may also be accompanied by gastrointestinal disturbances and a reduction or elimination of lactobacilli in the intestinal microflora. Lactobacilli are part of the normal gram-positive anaerobic microflora. Through the production of lactic and acetic acids, hydrogen peroxide, and antimicrobial substances, these microorganisms possibly contribute to the maintenance of colonization resistance. Several studies have indicated a protective effect of lactobacilli against potential pathogens in the gastrointestinal tract. In view of these beneficial properties, it is considered important to maintain or increase the levels of lactobacilli in the intestinal microflora.

Animals↗
PubMed1991

Utilization of early Maillard reaction products by humans.

The paper reports results from balance trials with a total of 42 volunteers testing glycated casein samples containing the Maillard-(Amadori-) product fructoselysine (= FL, analysed as furosine). On a almost FL free diet only traces of FL were excreted. If test meals with 0.8-5.0 g FL were given, only 2.0-1.2% were found in the urine. In the feces of 3 persons eating 0.96 g FL in a single meal 2.6-5.6% were excreted. It is concluded that digestion is the main limiting factor for the uptake of FL. Possibly also the transit time of the ingesta through the gastro intestinal tract is important. Since there is no indication from animal studies for a utilization of FL it can be assumed that the microorganism in the hind gut decompose the main part of the not recovered more than 90% of FL. Obviously the bacterial flora is more active and able to attack such components as assumed until now.

Administration, Oral↗
PubMedDate not supplied

Gastrointestinal manifestations in pediatric AIDS.

The pathologic changes in the gastrointestinal tract of children with AIDS are variable, clinically significant, and reflect multisystemic disease processes. Inflammation, changes in the lymphoid tissue, miscellaneous lesions, and tumors are documented in 58 patients in addition to cases reported in the literature. Cytomegalovirus infection of the gastrointestinal tract, associated with ulcerations, hemorrhage, perforations, and intestinal obstruction, carries a high morbidity and mortality, whereas the remaining infections are not life threatening. Special stains and electron micrographic examination are important to identify correctly certain microorganisms such as mycobacterium avium intracellulare, cryptosporidia, and microsporidia. Lymphoproliferative changes of the gastrointestinal tract, a component of the generalized lymphoproliferative process, need to be characterized by tumor markers and cytogenetic studies. Within the miscellaneous lesions, AIDS associated arteriopathy can be complicated by intestinal ulceration and perforation. Both lymphomas and smooth muscle tumor in children with AIDS are related to Epstein-Barr virus infection. The smooth muscle tumors are frequently malignant and multiple.

AIDS-Related Opportunistic Infections↗
PubMed1992

Effect of a broad-spectrum cephalosporin on the oral and intestinal microflora in patients undergoing colorectal surgery.

The influence of ceftriaxone on oral and intestinal flora was investigated in 10 patients undergoing colorectal surgery. Ceftriaxone was given intravenously in one 2g dose before anesthesia. Saliva and feces samples were collected and analyzed on day 0, 3, 5, 14 and 28 after drug administration. All specimens were cultured quantitatively for aerobic and anaerobic microorganisms; representative colonies of each morphologic type of organism cultured were identified. The oral aerobic flora was somewhat affected by the administration of ceftriaxone. In all patients the number of Streptococci, Staphylococci and Neisseria decreased during the 5 days after ceftriaxone administration. No significant changes in the number of anaerobic commensal occurred. The oral microflora of all patients after 14 days had returned to normal. The aerobic fecal flora was considerably affected: in all patients enterobacteria were eliminated or strongly suppressed. Only minor changes in the number of aerobic gram-positive bacteria were observed, and the anaerobic intestinal flora showed only minor alterations. On day 28 the intestinal flora were normalized in all respects. No new colonizing microorganisms were isolated during the investigation period and no colonization with ceftriaxone-resistant bacteria was observed. No postoperative infection occurred and no adverse effects were registered.

Aged↗
PubMed1996

Differentiation-associated antimicrobial functions in human colon adenocarcinoma cell lines.

We report that the enterocytic cells of the HT-29 glc-/+ cell subpopulation strongly expressed two antimicrobial enzymes: the lysozyme and alpha1-antitrypsin. Moreover, we found that 20 to 30% of these cells expressed positive immunoreactivity using the mAbs directed against the gut porcine PR-39 and cecropin P1 antimicrobial peptides, but did not express immunreactivity against the human antimicrobial polymorphonucleated neutrophil-associated HNP 1-3 defensin and the Xenopus skin magainin. The HT-29 glc-/+ cell subpopulation develops bacteriolytic activity against the enterovirulent diffusely adhering C1845 Escherichia coli characterized by dramatic alterations of the bacterial cell, suggesting lysis, and bacterial death. In contrast, no expression of immunoreactivity against the antimicrobial peptides and no C1845 bacterial alteration were found in the cultured human embryonic undifferentiated INT407 cells and the colon adenocarcinoma T84 crypt cells. The development of the bacterial alteration and the expression of the antimicrobial components were examined as a function of the cell differentiation using the Caco-2 cell line which spontaneously differentiates in culture. We found that the bacterial alteration and the expression of the PR-39 immunoreactivity are differentiation-associated events. Altogether, our results suggest that in the intestine the enterocytes could develop antimicrobial defenses participating in the protection of the gut epithelium against enterovirulent microorganisms.

Bacterial Adhesion↗
PubMed2002

Helicobacter pylori infection in pediatrics.

In the past year the main interest was focused on the role of family for transmission of Helicobacter pylori to children; the evaluation of noninvasive diagnostic tests, especially in young children; extra-intestinal clinical manifestations; the lack of consensus on treatment; and the problem of high resistance of the microorganism to antibiotics.

Antibodies↗
PubMed1998

M cells as portals of entry for HIV.

Accumulating evidence points toward active uptake by mucosal antigen sampling cells as the mechanism for rectal HIV acquisition. Organized lymphoid tissue in the intestine consists of lymphoid follicles with an epithelium containing M cells specialized for uptake and transport of microorganisms, bringing them into contact with lymphoid cells. M cells have been found in the human colon and rectum, and adherence and uptake of HIV by M cells in mouse and rabbit Peyer's patches has been demonstrated in vitro. In an in vivo mouse model of viral acquisition, reovirus is actively taken up by M cells into rectal lymphoid tissue containing CD4 lymphocytes and macrophages, which are targets and replication sites for HIV. Immunization strategies for prevention of HIV transmission should include a mucosal component to prevent initial entry, since elimination from cellular sanctuaries remains an elusive goal.

Animals↗
PubMed2006

Effects of temperature and sand on E. coil survival in a northern lake water microcosm.

A concern for public health officials is the presence of Escherichia coli (E. coli), an indicator of fecal contamination, in monitoring recreational waters. While E. coli is unlikely to cause disease in humans, its presence may indicate other more pathogenic microorganisms. Many factors can lead to changes in the survival of E. coli outside of the animal intestine and may affect the probability of colonizing a new host. Survival of bacteria in recreational water has been linked to water temperature, and most recently to the presence of sand on the beach. This project looked at the survival of an environmental E. coli isolate in lake water. Lake water microcosms were placed at 4, 10, 14, or 25 degrees C for up to 36 d and an enzyme-substrate test (Colisure, IDEXX Corp.) was used to determine the most probable number (MPN) of E. coli/100 ml water. E. coli numbers at all temperatures declined over the duration of the experiment. The decline was most pronounced at 14 degrees C and was slowest at 4 degrees C. The presence of sand in the microcosm increased the time that E. coli survived, regardless of temperature. From a beach management standpoint, these findings indicate that E.coli may persist in the environment in cooler water longer than in the warmer water encountered in late summer.

Cell Proliferation↗