scholarly journals Intestinal Mucus Alters the Ability of Probiotic Bacteria To Bind Aflatoxin B1 In Vitro

2004 ◽  
Vol 70 (10) ◽  
pp. 6306-6308 ◽  
Author(s):  
S. Gratz ◽  
H. Mykkänen ◽  
A. C. Ouwehand ◽  
R. Juvonen ◽  
S. Salminen ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Probiotic Bacteria ◽  
Dependent Manner ◽  
Surface Binding ◽  
Intestinal Mucus ◽  
Aflatoxin B ◽  
Strain Dependent

ABSTRACT Several probiotics are known to bind aflatoxin B1 (AFB1) to their surfaces and to adhere to intestinal mucus. In this study, preincubation of two probiotic preparations with either AFB1 or mucus reduced the subsequent surface binding of mucus and AFB1, respectively, in a strain-dependent manner.

Aflatoxin B1 Binding by a Mixture of Lactobacillus and Propionibacterium: In Vitro Versus Ex Vivo

2005 ◽  
Vol 68 (11) ◽  
pp. 2470-2474 ◽  
Author(s):  
S. GRATZ ◽  
H. MYKKÄNEN ◽  
H. EL-NEZAMI
Keyword(s):  
Aflatoxin B1 ◽  
Ex Vivo ◽  
Animal Health ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Bacteria ◽  
Tissue Uptake ◽  
Bacterial Surface ◽  
Intestinal Mucus ◽  
Food And Feed

Aflatoxin B1 (AFB1) is a well-known carcinogen and reducing its bioavailability is of great interest for human and animal health. Several probiotic bacteria are able to bind AFB1 in vitro, including Lactobacillus rhamnosus LC-705 and Propionibacterium freudenreichii subsp. shermanii JS. A mixture of these two probiotics is used by the food and feed industry as biopreservative (Bioprofit), making it a promising candidate for future applications. Consequently, this study aims to investigate the in vitro and ex vivo ability of this probiotic mixture to bind AFB1. For in vitro experiments, probiotic mixture was suspended in an AFB1 solution (5 μM), incubated for 1 to 30 min, centrifuged, and AFB1 residues were quantitated in supernatant and pellet. For ex vivo experiments, duodenal loops of chicks were ligated and injected with either AFB1 solution alone or probiotic mixture suspension and AFB1 solution. Lumen content was centrifuged and AFB1 was quantitated in supernatant and pellet. Additionally, AFB1 was extracted from duodenal tissue to calculate tissue uptake. In vitro, 57 to 66% of AFB1 was removed from the solution by the probiotic mixture, but only 38 to 47% could be extracted from the bacterial surface. In ex vivo experiments, only up to 25% of AFB1 was bound by bacteria, and tissue uptake of AFB1 was significantly reduced when probiotic bacteria were present in the duodenal loop. Furthermore, the effect of intestinal mucus on the bacterial binding ability was investigated in vitro and was found to significantly reduce AFB1 binding by the probiotic mixture. However, probiotic mixture could only retard but not prevent AFB1 absorption in duodenal loops. Further work needs to assess the potential of probiotics in different experimental setups.

An aniline-substituted bile salt analog protects both mice and hamsters from multiple Clostridioides difficile strains

2021 ◽  
Author(s):  
Jacqueline R. Phan ◽  
Dung M. Do ◽  
Minh Chau Truong ◽  
Connie Ngo ◽  
Julian H. Phan ◽  
...  
Keyword(s):  
Bile Salt ◽  
Spore Germination ◽  
Dependent Manner ◽  
Germination Inhibitors ◽  
New Methods ◽  
Clostridioides Difficile ◽  
Antibiotic Associated Diarrhea ◽  
Careful Screening ◽  
Strain Dependent

Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea. The emergence of hypervirulent C. difficile strains has led to increases in both hospital- and community-acquired CDI. Furthermore, CDI relapse from hypervirulent strains can reach up to 25%. Thus, standard treatments are rendered less effective, making new methods of prevention and treatment more critical. Previously, the bile salt analog CamSA was shown to inhibit spore germination in vitro and protect mice and hamsters from C. difficile strain 630. Here, we show that CamSA was less active at preventing spore germination of other C. difficile ribotypes, including the hypervirulent strain R20291. Strain-specific in vitro germination activity of CamSA correlated with its ability to prevent CDI in mice. Additional bile salt analogs were screened for in vitro germination inhibition activity against strain R20291, and the most active compounds were tested against other strains. An aniline-substituted bile salt analog, (CaPA), was found to be a better anti-germinant than CamSA against eight different C. difficile strains. In addition, CaPA was capable of reducing, delaying, or preventing murine CDI signs in all strains tested. CaPA-treated mice showed no obvious toxicity and showed minor effects on their gut microbiome. CaPA’s efficacy was further confirmed by its ability to prevent CDI in hamsters infected with strain 630. These data suggest that C. difficile spores respond to germination inhibitors in a strain-dependent manner. However, careful screening can identify anti-germinants with broad CDI prophylaxis activity.

Inhibition of leukocyte locomotion by hyaluronic acid

1981 ◽  
Vol 48 (1) ◽  
pp. 315-331
Author(s):  
J.V. Forrester ◽  
P.C. Wilkinson
Keyword(s):  
Molecular Weight ◽  
Visual Analysis ◽  
Cell Movement ◽  
Chemotactic Factor ◽  
Major Constituent ◽  
Dependent Manner ◽  
Surface Binding ◽  
Micropore Filter

The effect of hyaluronate on neutrophil motility in vitro was studied by the micropore filter technique and by direct visual analysis of the locomotion of neutrophils on glass. Both directed and random locomotion of neutrophils was inhibited by physiological concentrations (0.5-6.0 mg ml(−1)) of hyaluronate in a dose- and molecular weight-dependent manner. Inhibition of cell movement was more pronounced for high molecular weight chemoattractants such as casein than for small chemotactic peptides such as f-Met-Leu-Phe. Chemotactic factor gradient formation in filter chambers was profoundly retarded by hyaluronate, which may partly explain the inhibitory effects of hyaluronate on directed neutrophil locomotion. In addition, hyaluronate inhibited the binding of chemotactic factor to the neutrophil surface. This effect, together with a reduction in cell-to-substratum adhesion, may provide an additional explanation for hyaluronate-induced inhibition of random neutrophil locomotion. Inhibition of locomotion by hyaluronate was easily reversed by washing the cells free of hyaluronate; thus competition by hyaluronate for cell-surface binding sites is unlikely, and physical effects such as steric exclusion or molecular sieving by the large hyaluronate polymer provide the most probable explanations of its inhibitory effect on cell locomotion. Since hyaluronate is a major constituent of tissue matrices, these results draw attention to the importance of the extracellular environment in regulating inflammatory cell movement in vivo.

scholarly journals Lipoteichoic acid depletion in Lactobacillus impacts cell morphology and stress response but does not abolish mercury surface binding

2020 ◽  
Vol 11 (8) ◽  
pp. 791-802
Author(s):  
C. Alcántara ◽  
A. Crespo ◽  
C.L.S. Solís ◽  
V. Devesa ◽  
D. Vélez ◽  
...  
Keyword(s):  
Cell Wall ◽  
Toxic Metal ◽  
Lipoteichoic Acid ◽  
Dependent Manner ◽  
Surface Binding ◽  
Metal Sequestration ◽  
Functional Roles ◽  
Mutant Strains ◽  
Probiotic Lactobacilli ◽  
Strain Dependent

Lipoteichoic acid (LTA) is a key component of the cell wall of most Gram-positive bacteria and plays many structural and functional roles. In probiotic lactobacilli, the function of LTA in mediating bacteria/host cross-talk has been evidenced and it has been postulated that, owing to its anionic nature, LTA may play a role in toxic metal sequestration by these bacteria. However, studies on this last aspect employing strains unable to synthesise LTA are lacking. We have inactivated the LTA polymerase encoding gene ltaS in two different Lactobacillus plantarum strains. Analysis of LTA contents in wild-type and ltaS mutant strains corroborated the role of this gene as a major contributor to LTA synthesis in L. plantarum. The mutant strains displayed strain-dependent anomalous cell morphologies that resulted in elongated or irregular cells with aberrant septum formation. They also exhibited higher sensitivity to several stresses (osmotic and heat) and to antimicrobials that target the cell wall. The toxicity of inorganic [(Hg(II)] and organic mercury (methyl-Hg) was also increased upon ltaS mutation in a strain-dependent manner. However, the mutant strains showed 0 to 50% decrease in their capacity of Hg binding compared to their corresponding parental strains. This result suggests a partial contribution of LTA to Hg binding onto the cell surface that was dependent on the strain and the Hg form.

Probiotic bacteria as potential detoxification tools: assessing their heavy metal binding isotherms

2006 ◽  
Vol 52 (9) ◽  
pp. 877-885 ◽  
Author(s):  
Fandi Ibrahim ◽  
Teemu Halttunen ◽  
Raija Tahvonen ◽  
Seppo Salminen
Keyword(s):  
Heavy Metal ◽  
Metal Binding ◽  
Animal Health ◽  
Lactobacillus Rhamnosus ◽  
Dietary Exposure ◽  
Probiotic Bacteria ◽  
Dependent Manner ◽  
Binding Isotherms ◽  
Cadmium And Lead

Dietary exposure to heavy metals may have detrimental effects on human and animal health, even at low concentrations. Specific probiotic bacteria may have properties that enable them to bind toxins from food and water. We assessed the interaction of probiotic bacteria with cadmium and lead in vitro as an initial screening step to identify strains for heavy metal decontamination in food and intestinal models. Binding isotherms for cadmium and lead were characterized for Lactobacillus rhamnosus LC-705, Propionibacterium freudenreichii subsp. shermanii JS and a mix of them used by the food industry. Differences among the strains and their combinations in binding performance at a range of concentrations between 0.1 and 100 mg·L–1 were evaluated with the Langmuir model for biosorption. The effects of pH, contact time, and viability on the binding capacities were also investigated. All strains and their combinations were found to bind cadmium and lead efficiently at low concentration ranges commonly observed in foods. However, the two strains and their combinations differed significantly in their maximum binding capacities and affinities represented by the Langmuir constants Qmax and b, respectively. The binding seemed to occur instantaneously and in a pH-dependent manner, which can be perfectly described by a segmented linear–plateau model.Key words: probiotics, cadmium, lead, binding, Langmuir.

scholarly journals Aflatoxin B1 and Aflatoxin M1 Induce Compromised Intestinal Integrity through Clathrin-Mediated Endocytosis

Toxins ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 184
Author(s):  
Yanan Gao ◽  
Xiaoyu Bao ◽  
Lu Meng ◽  
Huimin Liu ◽  
Jiaqi Wang ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Intestinal Barrier ◽  
Fluorescein Isothiocyanate ◽  
Intestinal Barrier Function ◽  
Aflatoxin M1 ◽  
Dependent Manner ◽  
Simultaneous Exposure ◽  
Intestinal Integrity

With the growing diversity and complexity of diet, humans are at risk of simultaneous exposure to aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1), which are well-known contaminants in dairy and other agricultural products worldwide. The intestine represents the first barrier against external contaminants; however, evidence about the combined effect of AFB1 and AFM1 on intestinal integrity is lacking. In vivo, the serum biochemical parameters related to intestinal barrier function, ratio of villus height/crypt depth, and distribution pattern of claudin-1 and zonula occluden-1 were significantly affected in mice exposed to 0.3 mg/kg b.w. AFB1 and 3.0 mg/kg b.w. AFM1. In vitro results on differentiated Caco-2 cells showed that individual and combined AFB1 (0.5 and 4 μg/mL) and AFM1 (0.5 and 4 μg/mL) decreased cell viability and trans-epithelial electrical resistance values as well as increased paracellular permeability of fluorescein isothiocyanate-dextran in a dose-dependent manner. Furthermore, AFM1 aggravated AFB1-induced compromised intestinal barrier, as demonstrated by the down-regulation of tight junction proteins and their redistribution, particularly internalization. Adding the inhibitor chlorpromazine illustrated that clathrin-mediated endocytosis partially contributed to the compromised intestinal integrity. Synergistic and additive effects were the predominant interactions, suggesting that these toxins are likely to have negative effects on human health.

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