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Deconjugated Bile Salts Produced by Extracellular Bile-Salt Hydrolase-Like Activities from the Probiotic Lactobacillus johnsonii La1 Inhibit Giardia duodenalis In vitro Growth

View Article: PubMed Central - PubMed

ABSTRACT

Giardiasis, currently considered a neglected disease, is caused by the intestinal protozoan parasite Giardia duodenalis and is widely spread in human as well as domestic and wild animals. The lack of appropriate medications and the spread of resistant parasite strains urgently call for the development of novel therapeutic strategies. Host microbiota or certain probiotic strains have the capacity to provide some protection against giardiasis. By combining biological and biochemical approaches, we have been able to decipher a molecular mechanism used by the probiotic strain Lactobacillus johnsonii La1 to prevent Giardia growth in vitro. We provide evidence that the supernatant of this strain contains active principle(s) not directly toxic to Giardia but able to convert non-toxic components of bile into components highly toxic to Giardia. By using bile acid profiling, these components were identified as deconjugated bile-salts. A bacterial bile-salt-hydrolase of commercial origin was able to mimic the properties of the supernatant. Mass spectrometric analysis of the bacterial supernatant identified two of the three bile-salt-hydrolases encoded in the genome of this probiotic strain. These observations document a possible mechanism by which L. johnsonii La1, by secreting, or releasing BSH-like activity(ies) in the vicinity of replicating Giardia in an environment where bile is present and abundant, can fight this parasite. This discovery has both fundamental and applied outcomes to fight giardiasis, based on local delivery of deconjugated bile salts, enzyme deconjugation of bile components, or natural or recombinant probiotic strains that secrete or release such deconjugating activities in a compartment where both bile salts and Giardia are present.

No MeSH data available.


Related in: MedlinePlus

G. duodenalis growth is inhibited by enzymatically active C. perfringens BSH in the presence of conjugated bile salts (0.2 g/L). Commercial C. perfringens BSH, enzymatically active or heat-inactivated (100°C, 5 min) was added to G. duodenalis culture medium in the presence of either GDC, glycodeoxycholate; GCDC, glycochenodeoxycholate; TDC, taurodeoxycholate or TCDC; taurochenodeoxycholate. Values are the mean ± SD of at least three independent experiments. Letters indicate significant differences between treatments (Kruskall-Wallis, p < 0.05).
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Figure 6: G. duodenalis growth is inhibited by enzymatically active C. perfringens BSH in the presence of conjugated bile salts (0.2 g/L). Commercial C. perfringens BSH, enzymatically active or heat-inactivated (100°C, 5 min) was added to G. duodenalis culture medium in the presence of either GDC, glycodeoxycholate; GCDC, glycochenodeoxycholate; TDC, taurodeoxycholate or TCDC; taurochenodeoxycholate. Values are the mean ± SD of at least three independent experiments. Letters indicate significant differences between treatments (Kruskall-Wallis, p < 0.05).

Mentions: To assess the capability of BSH enzymes to promote the bile-mediated anti-Giardia effect, BSH from the bacteria C. perfringens was tested for G. duodenalis growth inhibition in the presence of bile or pure conjugated bile salts. As notified (Table 3), glycine or taurine conjugated bile salts, TDC, TCDC, GDC, and GCDC have no inhibitory activity on G. duodenalis growth in KM-FCS. In contrast, the addition of C. perfringens BSH to the culture in the presence of the conjugated bile salts led to a remarkable parasite inhibition within the 24 h of the assay, with inhibition ranges of 95–100% depending on the conjugated bile salt (Figures 5B, 6). Heat inactivation of C. perfringens BSH (100°C, 5 min) dramatically reduced or even abolished its anti-Giardia activity (less than 20% growth inhibition depending on the conjugated bile salts tested, Figure 6) indicating that parasite growth inhibition depends on BSH enzymatic activity.


Deconjugated Bile Salts Produced by Extracellular Bile-Salt Hydrolase-Like Activities from the Probiotic Lactobacillus johnsonii La1 Inhibit Giardia duodenalis In vitro Growth
G. duodenalis growth is inhibited by enzymatically active C. perfringens BSH in the presence of conjugated bile salts (0.2 g/L). Commercial C. perfringens BSH, enzymatically active or heat-inactivated (100°C, 5 min) was added to G. duodenalis culture medium in the presence of either GDC, glycodeoxycholate; GCDC, glycochenodeoxycholate; TDC, taurodeoxycholate or TCDC; taurochenodeoxycholate. Values are the mean ± SD of at least three independent experiments. Letters indicate significant differences between treatments (Kruskall-Wallis, p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037171&req=5

Figure 6: G. duodenalis growth is inhibited by enzymatically active C. perfringens BSH in the presence of conjugated bile salts (0.2 g/L). Commercial C. perfringens BSH, enzymatically active or heat-inactivated (100°C, 5 min) was added to G. duodenalis culture medium in the presence of either GDC, glycodeoxycholate; GCDC, glycochenodeoxycholate; TDC, taurodeoxycholate or TCDC; taurochenodeoxycholate. Values are the mean ± SD of at least three independent experiments. Letters indicate significant differences between treatments (Kruskall-Wallis, p < 0.05).
Mentions: To assess the capability of BSH enzymes to promote the bile-mediated anti-Giardia effect, BSH from the bacteria C. perfringens was tested for G. duodenalis growth inhibition in the presence of bile or pure conjugated bile salts. As notified (Table 3), glycine or taurine conjugated bile salts, TDC, TCDC, GDC, and GCDC have no inhibitory activity on G. duodenalis growth in KM-FCS. In contrast, the addition of C. perfringens BSH to the culture in the presence of the conjugated bile salts led to a remarkable parasite inhibition within the 24 h of the assay, with inhibition ranges of 95–100% depending on the conjugated bile salt (Figures 5B, 6). Heat inactivation of C. perfringens BSH (100°C, 5 min) dramatically reduced or even abolished its anti-Giardia activity (less than 20% growth inhibition depending on the conjugated bile salts tested, Figure 6) indicating that parasite growth inhibition depends on BSH enzymatic activity.

View Article: PubMed Central - PubMed

ABSTRACT

Giardiasis, currently considered a neglected disease, is caused by the intestinal protozoan parasite Giardia duodenalis and is widely spread in human as well as domestic and wild animals. The lack of appropriate medications and the spread of resistant parasite strains urgently call for the development of novel therapeutic strategies. Host microbiota or certain probiotic strains have the capacity to provide some protection against giardiasis. By combining biological and biochemical approaches, we have been able to decipher a molecular mechanism used by the probiotic strain Lactobacillus johnsonii La1 to prevent Giardia growth in vitro. We provide evidence that the supernatant of this strain contains active principle(s) not directly toxic to Giardia but able to convert non-toxic components of bile into components highly toxic to Giardia. By using bile acid profiling, these components were identified as deconjugated bile-salts. A bacterial bile-salt-hydrolase of commercial origin was able to mimic the properties of the supernatant. Mass spectrometric analysis of the bacterial supernatant identified two of the three bile-salt-hydrolases encoded in the genome of this probiotic strain. These observations document a possible mechanism by which L. johnsonii La1, by secreting, or releasing BSH-like activity(ies) in the vicinity of replicating Giardia in an environment where bile is present and abundant, can fight this parasite. This discovery has both fundamental and applied outcomes to fight giardiasis, based on local delivery of deconjugated bile salts, enzyme deconjugation of bile components, or natural or recombinant probiotic strains that secrete or release such deconjugating activities in a compartment where both bile salts and Giardia are present.

No MeSH data available.


Related in: MedlinePlus