The binding of Ca2+ to taurine- and glycine-conjugated bile salt micelles

Rajagopalan, Natarajan; Lindenbaum, Siegfried

doi:10.1016/0005-2760(82)90010-8

Cited by 62 publications

(25 citation statements)

References 10 publications

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“…Calcium and other divalent cations stabilize exopolysaccharide, and removal can cause the collapse of the biofilm (41). Because some bile salts can chelate calcium and other divalent cations, we questioned whether TC chelates Ca 2ϩ to destabilize or degrade the biofilm matrix (42). However, supplemental calcium did not prevent TC-enhanced detachment (see Fig.…”

Section: Resultsmentioning

confidence: 98%

Host Intestinal Signal-Promoted Biofilm Dispersal Induces Vibrio cholerae Colonization

Hay

Zhu

2015

Infect Immun

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Vibrio cholerae causes human infection through ingestion of contaminated food and water, leading to the devastating diarrheal disease cholera. V. cholerae forms matrix-encased aggregates, known as biofilms, in the native aquatic environment. While the formation of V. cholerae biofilms has been well studied, little is known about the dispersal from biofilms, particularly upon entry into the host. In this study, we found that the exposure of mature biofilms to physiologic levels of the bile salt taurocholate, a host signal for the virulence gene induction of V. cholerae, induces an increase in the number of detached cells with a concomitant decrease in biofilm mass. Scanning electron microscopy micrographs of biofilms exposed to taurocholate revealed an altered, perhaps degraded, appearance of the biofilm matrix. The inhibition of protein synthesis did not alter rates of detachment, suggesting that V. cholerae undergoes a passive dispersal. Cell-free media from taurocholate-exposed biofilms contains a larger amount of free polysaccharide, suggesting an abiotic degradation of biofilm matrix by taurocholate. Furthermore, we found that V. cholerae is only able to induce virulence in response to taurocholate after exit from the biofilm. Thus, we propose a model in which V. cholerae ingested as a biofilm has coopted the host-derived bile salt signal to detach from the biofilm and go on to activate virulence.

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Section: Resultsmentioning

confidence: 98%

Host Intestinal Signal-Promoted Biofilm Dispersal Induces Vibrio cholerae Colonization

Hay

Zhu

2015

Infect Immun

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“…Since a detailed study of the molecular mechanism is beyond the scope of the present paper, a few tentative conclusions may be drawn. First, the difference in binding between glycine and taurine conjugates is reminiscent of the reported difference in their affinity for Ca2+ (Williamson & Percy-Robb, 1979;Rajagopalan & Lindenbaum, 1982). The latter is attributed to the S03group in taurine being in a more hydrated state than the carboxylate group in glycine (Rajagopalan & Lindenbaum, 1982).…”

Section: Discussionmentioning

confidence: 99%

“…First, the difference in binding between glycine and taurine conjugates is reminiscent of the reported difference in their affinity for Ca2+ (Williamson & Percy-Robb, 1979;Rajagopalan & Lindenbaum, 1982). The latter is attributed to the S03group in taurine being in a more hydrated state than the carboxylate group in glycine (Rajagopalan & Lindenbaum, 1982). Preliminary experiments with unconjugated deoxycholate showed that its binding to insoluble calcium phosphate is analogous to that of glycodeoxycholate.…”

Section: Discussionmentioning

confidence: 99%

Differential binding of glycine- and taurine-conjugated bile acids to insoluble calcium phosphate

Meer¹,

Vries²

1985

Biochemical Journal

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It is demonstrated that bile acids bind to insoluble calcium phosphate at pH values beyond 5.5. Significant binding occurs with glycine-conjugated dihydroxy bile acids. Results indicate that these bile acids are bound in a micellar mode. Taurine conjugation almost completely inhibits the binding of these bile acids to insoluble calcium phosphate. Since glycine-conjugated dihydroxy bile acids are predominant in the rabbit, but not in the rat, our results suggest an explanation for the intriguing species-dependence of casein-induced hypercholesterolaemia, which is high in the rabbit but absent in the rat.

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“…The effect of hydroxyl number and position and the difference between glycine-and taurine-conjugated micellar bile salts was determined by Rajagopalan and Lindenbaum (90). Like many other bile salt properties, Ca2+ binding increased with increasing hydrophobicity.…”

Section: Bile Salt-calcium Interactions the Centersmentioning

confidence: 99%