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Metabolic Engineering of Probiotic Saccharomyces boulardii Enables Intestinal 3-Hydroxybutyrate Delivery and Alters Short-Chain Fatty Acid Profiles in Mice.

3-Hydroxybutyric acid (3-HB) is a bioactive ketone body involved in the regulation of intestinal inflammation and metabolic homeostasis. Although engineered bacterial probiotics have been developed for localized 3-HB delivery, their susceptibility to antibacterial antibiotics may limit their use during concurrent antibiotic treatment. The probiotic yeast Saccharomyces boulardii offers an alternative host for intestinal 3-HB delivery because of its compatibility with antibacterial antibiotics and the availability of well-established genetic engineering tools. Here, we engineered S. boulardii for 3-HB production using Cas9-mediated genome editing. A heterologous 3-HB biosynthetic pathway was introduced into S. boulardii MYA-797, and endogenous acetyl-CoA and ethanol metabolism was subsequently rewired by overexpressing ACS1, deleting ADH1, and overexpressing ADH7. The optimized strain, SbDY02, produced 1.7 g/L 3-HB under microaerobic conditions. Oral administration of SbDY02 to C57BL/6J mice increased fecal 3-HB and short-chain fatty acid (SCFA) concentrations by 1.89-fold and 1.68-fold, respectively, compared with mice receiving the parental strain. Repeated administration also increased fecal acetate and circulating total SCFAs, butyrate, and propionate. In human colonic epithelial cells, purified 3-HB attenuated lipopolysaccharide-induced p38 MAPK phosphorylation, supporting its direct activity toward inflammation-associated epithelial signaling. To our knowledge, this study provides the first demonstration of a 3-HB-producing probiotic yeast and links central metabolic engineering of S. boulardii with increased 3-HB availability, altered SCFA profiles, and a host-relevant epithelial response.

3-hydroxybutyrate↗

Probiotics and the gastrointestinal tract: where are we in 2005?

Probiotic agents are live microbes or components of microbes that have a positive effect on the host. They exert their action through interplay with the immune system of the host. Some of this effect is local and some is systemic. The full story is yet to be discovered. Probiotics have a definite positive effect on rotavirus diarrhea, post antibiotic diarrhea and pouchitis. Their exact role in inflammatory bowel disease, irritable bowel syndrome, other forms of infectious diarrhea, and prevention of cancer is yet to be determined. This review summarizes the data about probiotics in these conditions.

Diarrhea↗

Probiotics down-regulate flaA sigma28 promoter in Campylobacter jejuni.

Lactobacilli and bifidobacteria are important members of the gastrointestinal microflora of humans and animals and are thought to have positive effects on human health. Therefore, there is an increasing interest in using these microorganisms as probiotics to be incorporated into either fermented dairy products or tablets. However, convincing scientific data that support claims of their health benefits are scarce. The effect of cell-free extracts of milk fermented by 10 probiotic bacteria (five Bifidobacterium strains and five Lactobacillus strains) on the expression of the flaA gene of Campylobacter jejuni was assessed using a fusion between the flaA sigma28 promoter and a promoterless luxCDABE cassette carried on the plasmid pRYluxCDABE, which resulted in strains with quantifiable luminescence linked to flaA sigma28 promoter activity. Cell-free extracts of milk fermented by all of the tested probiotic strains inhibited the growth of the C. jejuni and down-regulatedflaA sigma28 promoter activity. Two nonprobiotic lactic acid bacterial strains, Lactococcus lactis and Streptococcus thermophilus, were less inhibitory.

Animals↗

Inhibitory effects of Enterococcus strains obtained from a probiotic product on in vitro growth of Salmonella enterica serovar enteritidis strain IFO3313.

Enterococcus faecium and Enterococcus gallinarum strains were isolated from a commercial probiotic product and the effects of these strains on the growth of Salmonella enterica serovar Enteritidis strain IFO3313 were investigated. Viable cell counts of Salmonella Enteritidis in mixed cultures with the probiotic product isolate of E. faecium were significantly (P < 0.05) lower than those in pure cultures after 6, 8, and 24 h when the cultures were incubated in heart infusion broth at 37 and 41 degrees C. Significant differences in viable cell counts of Salmonella Enteritidis in mixed cultures with the probiotic product isolate of E. gallinarum and those in pure cultures were also observed after 8 and 24 h at 37 and 41degrees C. Similar observations were shown in mixed cultures of Salmonella Enteritidis with the reference strains of E. faecium GIFU8355 and E. gallinarum ATCC 49573. Significant differences in viable cell counts of these enterococcal strains were not shown among pure and mixed cultures with Salmonella Enteritidis. The pH values in pure and mixed cultures were 7.0 or 7.5 throughout the experiments. E. faecium strains were found to harbor the genes encoding enterocins A and B and showed inhibitory zones with a diameter of 4 to 6 mm against growth of Salmonella Enteritidis in the enterocin production assays. However, the E. gallinarum strains possessed neither of the enterocin genes tested and exhibited no inhibition zone in the enterocin production assays. These results indicated that enterococcal strains exhibit inhibitory effects on the growth of Salmonella Enteritidis and these effects were due to both enterocin and nonenterocin factors.

Antibiosis↗

Mode of inactivation of probiotic bacteria affects interleukin 6 and interleukin 8 production in human intestinal epithelial-like Caco-2 cells.

Five lactic acid bacteria and two bifidobacteria strains were heat or irradiation inactivated. Inactivated cultures were evaluated for their effects on cytokines interleukin (IL) 6 and IL-8 production in human intestinal-like Caco-2 cells. For both heat- and irradiation-inactivated cultures, production of IL-6 and IL-8 was dependent on the specific microorganism. However, with all of the cultures, both IL-6 and IL-8 production was significantly higher (P < 0.05) in Caco-2 cells that were treated with heat-inactivated probiotic bacteria compare to the irradiation-inactivated bacteria. In the majority of the cases, heat-inactivated bacteria induced IL-6 and IL-8 production, whereas irradiation-inactivated bacteria attenuated both cytokine production. Our results indicate that the same probiotic bacteria used in the same cell culture could provide opposite cytokine production and immune modulation results based on its mode of inactivation; therefore, it is important to describe inactivation methods and conditions in detail when characterizing probiotic effects.

Bifidobacterium↗

[Modulation of gastrointestinal physiology through probiotic strains of Lactobacillus casei and Bifidobacterium bifidum].

The products called functional foods, which besides being merely nutritional have different beneficial effects on the organism, are situated in the context of diet and health promotion. Amongst these functional foods we can distinguish, amongst others, between probiotic and prebiotic compounds. The micro-organisms most widely used in probiotic foods belong to the Lactobacillus and Bifidobacterium types. In this article we have studied the effect of diets supplemented with Lactobacillus casei or Bifidobacterium bifidum on animal development and especially on the intestinal function, centred on their immune, digestive and absorptive activity in growing animals. The bacteria strains used modify the activity of the small intestine of healthy mice, significantly affecting their enzymatic activity (sucrase, maltase and aminopeptidase) and the collection of nutrients (galactose and glycilsarcosine), as well as the intestinal immune activity (higher number of Peyer's patches). However, these effects do not appear to disturb the development of the growing animals since no significant differences are appreciated in their body weight or in their blood parameters. These results make clear the possible beneficial effects on intestinal physiology and contribute to the understanding of the possible mechanisms of action of the probiotics, which could be employed in the preventive treatment of different pathologies related to the digestive apparatus.

Animals↗

Effect of a dietary supplement containing probiotic bacteria plus vitamins and minerals on common cold infections and cellular immune parameters.

OBJECTIVE: A randomized, double-blind, placebo-controlled intervention study was carried out in order to investigate whether consumption of a dietary supplement containing probiotic bacteria plus vitamins and minerals over a period of at least three months in winter/spring affects the duration, frequency, and severity of symptoms of naturally acquired common cold infections as well as cellular immune parameters. METHODS: 477 healthy men and women (aged 36 +/- 13, mean +/- SD) who had not been vaccinated against influenza were randomly assigned to a group who received daily the probiotic multivitamin and mineral supplement (verum) or a placebo, for three (n = 239) or for 5.5 months (n = 238). Cellular immune response was determined in 60 participants per study group by flow cytometry before and after 14 days of supplementation. RESULTS: The incidence of respiratory tract infections regarded as being virally induced was 13.6% lower in the verum group compared to the placebo group (p = 0.07). During respiratory tract infection episodes, the subjects recorded common cold and influenza-like symptoms daily. All symptoms were reduced in the verum group. We found a relative reduction of 19% in the total symptom score (p = 0.12), 25% in influenza symptoms (p = 0.09), and 54% in the number of days with fever (p = 0.03). The duration of these infections was not affected. Leukocytes, lymphocytes, in particular T-lymphocytes including CD4+ and CD8+ cells, as well as monocytes were significantly higher increased in the verum group, during the first 14 days of supplementation compared to placebo. CONCLUSION: These data indicate that the intake of a dietary supplement containing probiotic bacteria plus vitamins and minerals during a period of at least three months in winter/spring may reduce the incidence and the severity of symptoms in common cold infections in otherwise healthy adults. This may be due to stimulated cellular immunity.

Adult↗

Occurrence of selected bacterial groups in the faeces of piglets fed with Bacillus coagulans as probiotic.

A microbiological analysis of piglet faeces was performed on samples collected from animals fed a diet without any additive, animals fed a diet that contained Bacillus coagulans CNCMI-1061 as probiotic, and animals fed a diet that contained Zn-bacitracin. The analysis was carried out in concurrence with a zootechnical trial. Selected bacterial groups (lactic acid bacteria, lacotococci, enterococci, aerobic and anaerobic cocci, total and faecal coliforms, clostridia, bacteroides, bifidobacteria) were determined at day 1 and after 1, 4 and 10 weeks of life. Numbers of enterococci, coliforms (especially faecal coliforms) showed a decrease over time with probiotic, more evident than with the antibiotic. Daily administration of B. coagulans allowed this bacterium to become integrated into the enteric microflora where it is transient. These results seem to show a positive effect of B. coagulans addition on cocci and faecal coliforms. We suggest that this probiotic may represent an alternative to antibiotics.

Animal Nutritional Physiological Phenomena↗

Comparison of three probiotics in the treatment of acute diarrhea in mentally retarded children.

BACKGROUND: This article aims to compare the use of VIS-01 (Yovis) with two other probiotics (lactic acid bacteria), such as Lactogèrmine and Codex in the treatment of acute diarrhea in children with mental retardation. A recent paper highlights the superiority of the first drug, claiming new perspectives in probiotic therapy. METHODS: The authors perform a prospective study on 33 mentally retarded children (mean age 10.3 years), divided in three groups, each treated with a different probiotic (VIS-01, Lactogèrmine and Codex) at the beginning of an acute diarrhea. These children were admitted at the Pediatric Unit of the Oasi Maria SS. Institute in Troina. The dosage was suited to the technical record of the drug. During the clinical course the following items have been recorded: number of evacuations; time of alvine normalization; presence, quality, and length of fever; other associated features or side effects. RESULTS: The time of alvine normalization did not show statistically significant differences between the three groups. CONCLUSIONS: In conclusion, the use of Yovis does not modify in a statistically significant way with respect to the remaining drugs the clinical course of acute diarrhea in the mentally retarded children of the present study.

Child↗

A review on the use of microorganisms as probiotics.

A literature review on the use of live microorganisms as probiotics is presented. Topics discussed are the definition of probiotic; the normal microflora of the digestive system of mammals, including bacterial interactions in the gut, colonization, modification of metabolic processes, and immunostimulation. Probiotics studies in humans and in farmed animals, with special emphasis on the use of Lactobacillus spp. and Bifidobacterium spp. are also discussed.

Adult↗

[Intestinal dysbacteriosis in antibacterial therapy and perspectives in treatment by antibiotic-resistant probiotics].

Effect of different antibiotics and standard antibacterial therapy regimes on intestine microflora was investigated. Lincozamides demonstrated the most negative effect. Early addition of probiotics to the treatment with antibacterials had positive effect. Susceptibility of 21 strains of normal microflora to 25 antibiotics was tested. Resistance to antibiotics of lactobacilli varied significantly (more among strains and less among species). It was shown that L. acidophilus (probiotic "Acilact") was resistant to metronidazole only. High resistance to antibiotics was shown for L. plantarum 8RA3, L. fermentum 90T4C (components of probiotic "Lactobacterin"), L. fermentum BL96, L. acidophilus BL and L. acidophilus (component of "Linex"). Susceptibility of microorganisms in complex formulation "Linex" to the modern antibiotics was low. It is concluded that the use of stable antibiotic-resistant strains of normal microflora is favorable as addition to antibiotic therapy.

Anti-Bacterial Agents↗

In vitro selection of probiotic lactobacilli: a critical appraisal.

The problem of choosing criteria for the in vitro selection of lactobacilli to be used as health-promoting, probiotic ingredients, in food and pharmaceutical preparations, was apparent even in the original works of Metchnikoff, who first proposed the therapeutic use of these bacteria. In the last decade, a consensus has been reached by scientists on some criteria, with particular attention being paid to the ecological origin of the bacteria, their tolerance to the hostile conditions of the stomach and the small intestine, and their ability to adhere to intestinal surfaces. Even though these criteria have been used to select probiotic lactobacilli, some doubts still remain about the real value of these criteria. A critical rethinking of selection criteria seems necessary in order to improve the process of developing better probiotics.

Animals↗

Evaluation in human volunteers of the potential anticarcinogenic activities of novel nutritional concepts: prebiotics, probiotics and synbiotics (the SYNCAN project QLK1-1999-00346).

Prebiotics is a recent novel food concept that includes food ingredients that are not digested in the human upper intestinal tract and hence arrive in the colon where they are selectively fermented by a limited number of colonic bacteria. Amongst these are bifidobacteria and lactobacilli, which are considered indicators of a well-balanced intestinal flora. Probiotics are bacteria that, while passing through the intestine, may exert specific beneficial effects on the host's physiology. In general, probiotics are members of the group of the lactic acid-producing bacteria. By means of a variety of experimental models it was demonstrated that prebiotic carbohydrates and probiotics consistently reduced processes of carcinogenesis and tumorigenesis. Synergistic chemopreventive actions were observed with combinations of the two, which together are called synbiotics. One of the most important causes of death in the ageing western population is colon cancer, which is typically associated with a western-style diet. On the basis of the available experimental data, an EU-funded research project (the SYNCAN project QLK1-1999-00346) was set up to evaluate whether synbiotics and prebiotics can be added to food without detriment to (and hopefully eventually improving) organoleptic properties. They are, as such, a good vector for importing nutritionally interesting properties into our diet.

Animals↗

[Evaluation of the activity of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt].

The effect of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt was evaluated. A yogurt mixture (10.6% non-fat solid liquids, 3% fat and 0.3% gelatin) was prepared, homogenized and pasteurized. Yogurt was inoculated with 0, 10(2), 10(4) and 10(6) CFU/mL of L. monocytogenes and 0.02% of traditional lactic culture YC 180 (Streptococcus thermophilus and Lactobacillus bulgaricus) and probiotic culture ABY-1 (Bifidobacterium longum, B. bifidum, B, infantis, Lactobacillus acidophilus, Streptococcus thermophilus y Lactobacillus delbrueckii subsp. bulgaricus). It was incubated for 3 h at 43 degrees C until pH reached an approximate value of 4.8, followed by refrigeration at 5 degrees C for 21 days. During fermentation, samples were taken every hour, and during storage every 3 days, analyzing pH and lactic, bifidobacteria and pathogen count for each time. It was demonstrated that there was no significant simple effect for the type of culture used (ABY-1 and YC 180) (p = 0.684) over the amount of L. monocytogenes present in yogurt during the fermentation and storage periods. The presence of bifidobacteria in the ABY-1 culture did not present a significant effect over L. monocytogenes. Neither the effect of time presented a significant effect over L. monocytogenes (p = 0.448). In this case, the ABY-1 and YC 180 cultures present a bacteriostatic effect over the pathogen. The probiotic cultures had a bacteriostatic but not bactericidal effect over L. monocytogenes. This is not related to the protective effect of these cultures in bowel, since in-vivo conditions favor the production of antimicrobial substances, such as bacteriocins that act over pathogens.

Bifidobacterium↗

Enumeration of probiotic pediococci in animal feed: interlaboratory study.

An enumeration method to be used as official control under Council Directive 70/524/EEC for probiotic pediococci used as feed additives was validated for consideration for adoption as Comitée Européen de Normalisation (CEN) and ISO standards. Seventeen laboratories in 11 European countries carried out an interlaboratory study. A spread plate method following BS ISO 15214:1998 using 4 different agars [MRS, acidified MRS, MRS with triphenyl tetrazolium chloride (TTC), and a newly developed pediococci selective medium (PSM)] was validated. Precision data in terms of repeatability (r) and reproducibility (R) of the method for each medium using different feeding stuffs with a high and a low inoculation level were determined. Pediococci were present in the samples in mixtures with other probiotics. The enumeration of pediococci on all agars showed an RSDr value of 0.4-3.1% and an RSDR of 1.3-4.8%. MRS agar was preferred, followed by acidified MRS and MRS + TTC agar. All 4 media gave similar counts. Depending on the presence and concentration of other probiotic, such as enterococci, lactobacilli, and yeast, acidified MRS or MRS + TTC agar are recommended. The PSM was selective for pediococci and can be used if this species is present at a concentration more than 10-fold lower than other species that can grow on the MRS agars. The methodology with all 4 media is not applicable to mineral feed.

Agar↗

[Dysbacteriosis and preparations with probiotic function].

Information on intestinal microecological disturbances (dysbacteriosis) and the preparations of probiotics, prebiotics and synbiotics used for the correction of resident normal colon microflora is presented. Probiotics are preparations containing live microbes or substances of microbial origin that, when introduced by natural methods are expected to confer beneficial physiologic, biochemical and immune effects to the host through the stabilization and the optimization of functions of normal microflora. Prebiotics are preparations containing a non-digestible food ingredient that beneficially affect the host by selectively stimulating the growth and the activity of a limited number of resident bacteria of normal microflora in the colon. Synbiotics are preparations obtained as the result of the rational combination of probiotics and prebiotics.

Bacterial Physiological Phenomena↗

The role of oxygen in the viability of probiotic bacteria with reference to L. acidophilus and Bifidobacterium spp.

The various therapeutic benefits of Lactobacillus acidophilus and Bifidobacterium spp. have resulted in their increased incorporation into dairy foods such as yoghurts. Currently however, the efficacy of these probiotic bacteria is limited by their poor survival during the shelf life of yoghurt. Oxygen toxicity is widely considered to be responsible for the cell deaths of these bacteria. The intestinal origins and the microaerophilic and anaerobic characteristics of L. acidophilus and Bifidobacterium spp. respectively, can render them susceptible to oxygen contained in the food products. This review discusses the influence of the dissolved oxygen in yogurt on the viability of these bacteria. Suggested techniques to protect these probiotic bacteria from oxygen toxicity are evaluated. Although the problem of oxygen toxicity in probiotic bacteria is regarded as significant, little is known however about the cellular interaction of these bacteria with oxygen. This review summarizes what is known about the biochemistry of oxygen toxicity in these bacteria. The various metabolic and biochemical responses of L. acidophilus and Bifidobacterium to oxygen are examined. Additionally, the importance of NADH oxidase and NADH peroxidase in the oxygen tolerance of these bacteria is evaluated and assays used to measure their cellular concentrations are discussed.

Bifidobacterium↗

Management of infant diarrhea with high-lactose probiotic-containing formula.

To study the influence of high-lactose probiotic-containing formula on the course of acute diarrhea, an experiment using a randomized controlled clinical trial with patients having acute diarrhea for 3 days was conducted. One hundred patients were allocated into two groups that were comparable for age, sex, and nutritional status. The test group was administered high-lactose Bifidobacterium bifidum-containing formula, while the control group had no high-lactose probiotic until the end of the experiment. The degree of subsequent diarrhea and recovery were monitored in both groups. The results for the test and control groups were analyzed and compared using the chi-square test and Fisher exact test with a significance level (alpha) of 0.05. The study results revealed that there was no significant difference between the test and control groups (p>0.05) as well as at positive clinical test (13%) and positive floating test (65%). However, the patients receiving probiotic-containing formula had significantly less frequency of stools, when compared with the control group (p<0.05).

Acute Disease↗