scholarly journals Partial replacement of bile salts causes marked changes of cholesterol crystallization in supersaturated model bile systems

1999 ◽  
Vol 340 (2) ◽  
pp. 445-451 ◽  
Author(s):  
Tomoji NISHIOKA ◽  
Susumu TAZUMA ◽  
Gunji YAMASHITA ◽  
Goro KAJIYAMA
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Rank Order ◽  
Gallstone Formation ◽  
Partial Replacement ◽  
Salt Composition ◽  
Human Bile ◽  
Identical Composition ◽  
Model Bile ◽  
Conjugated Bile Salts

Cholesterol crystallization is a key step in gallstone formation and is influenced by numerous factors. Human bile contains various bile salts having different hydrophobicity and micelle-forming capacities, but the importance of lipid composition to bile metastability remains unclear. This study investigated the effect of bile salts on cholesterol crystallization in model bile (MB) systems. Supersaturated MB systems were prepared with an identical composition on a molar basis (taurocholate/phosphatidylcholine/cholesterol, 152 mM:38 mM: 24 mM), except for partial replacement of taurocholate (10, 20, and 30%) with various taurine-conjugated bile salts. Cholesterol crystallization was quantitatively estimated by spectrophotometrically measuring crystal-related turbidity and morphologically scanned by video-enhanced microscopy. After partial replacement of taurocholate with hydrophobic bile salts, cholesterol crystallization increased dose-dependently without changing the size of vesicles or crystal morphology and the rank order of crystallization was deoxycholate > chenodeoxycholate > cholate (control MB). All of the hydrophilic bile salts (ursodeoxycholate, ursocholate and β-muricholate) inhibited cholesterol precipitation by forming a stable liquid-crystal phase, and there were no significant differences among the hydrophilic bile-salt species. Cholesterol crystallization was markedly altered by partial replacement of bile salts with a different hydrophobicity. Thus minimal changes in bile-salt composition may dramatically alter bile lipid metastability.

scholarly journals Bile Salt Composition and Distribution of the D-Cysteinolic Acid Conjugated Bile Salts in Fish

1996 ◽  
Vol 62 (4) ◽  
pp. 606-609 ◽  
Author(s):  
Takanobu Goto ◽  
Takuji Ui ◽  
Mizuho Une ◽  
Taiju Kuramoto ◽  
Kenji Kihira ◽  
...  
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Salt Composition ◽  
Conjugated Bile Salts

Effect of Conjugated Bile Salts on Antibiotic Susceptibility of Bile Salt–Tolerant Lactobacillus and Bifidobacterium Isolates

2000 ◽  
Vol 63 (10) ◽  
pp. 1369-1376 ◽  
Author(s):  
WILLIAM P. CHARTERIS ◽  
PHILLIP M. KELLY ◽  
LORENZO MORELLI ◽  
J. KEVIN COLLINS
Keyword(s):  
Bile Salt ◽  
Antibiotic Susceptibility ◽  
Bile Salts ◽  
Polymyxin B ◽  
Drug Combinations ◽  
Penicillin G ◽  
Dependent Manner ◽  
Salt Tolerant ◽  
Intrinsic Resistance ◽  
Conjugated Bile Salts

Virtually every antibiotic may cause in vivo alterations in the number, level, and composition of the indigenous microbiotae. The degree to which the microbiotae are disturbed depends on many factors. Although bile may augment antibiotic activity, studies on the effect of bile on the antibiotic susceptibility of indigenous and exogenous probiotic microorganisms are lacking. It was against this background that the antibiotic susceptibility of 37 bile salt–tolerant Lactobacillus and 11 Bifidobacterium isolates from human and other sources was determined in the presence of 0.5% wt/wt oxgall (conjugated bile salts). Oxgall did not affect the intrinsic resistance of lactobacilli to metronidazole (5 μg), vancomycin (30 μg), and cotrimoxazole (25 μg), whereas it resulted in a complete loss of resistance to polymyxin B (300 μg) and the aminoglycosides gentamicin (10 μg), kanamycin (30 μg), and streptomycin (10 μg) for most strains studied (P < 0.001). Oxgall did not affect the intrinsic resistance of bifidobacteria to metronidazole and vancomycin, whereas polymyxin B and co-trimoxazole resistance was diminished (P < 0.05) and aminoglycoside resistance was lost (P < 0.001). Seven lactobacilli, but no bifidobacteria strain, showed unaltered intrinsic antibiotic resistance profiles in the presence of oxgall. Oxgall affected the extrinsic susceptibility of lactobacilli and bifidobacteria to penicillin G (10 μg), ampicillin (10 μg), tetracycline (30 μg), chloramphenicol (30 μg), erythromycin (15 μg), and rifampicin (5 μg) in a source- and strain-dependent manner. Human strain–drug combinations of lactobacilli (P < 0.05) and bifidobacteria (P < 0.01) were more likely to show no change or decreased susceptibility compared with other strain-drug combinations. The antimicrobial activity spectra of polymyxin B and the aminoglycosides should not be considered limited to gram-negative bacteria but extended to include gram-positive genera of the indigenous and transiting microbiotae in the presence of conjugated bile salts. Those lactobacilli (7 of 37) that show unaltered intrinsic and diminished extrinsic antibiotic susceptibility in the presence of oxgall may possess greater upper gastrointestinal tract transit tolerance in the presence of antibiotics.

scholarly journals Synthesis of phospholipid-conjugated bile salts and interaction of bile salt-coated liposomes with cultured hepatocytes

2005 ◽  
Vol 46 (11) ◽  
pp. 2325-2338 ◽  
Author(s):  
G. Pütz ◽  
W. Schmider ◽  
R. Nitschke ◽  
G. Kurz ◽  
H. E. Blum
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Cultured Hepatocytes ◽  
Conjugated Bile Salts

Studies on the Action Mechanism for Cholesterol-Lowering of Lactobacillus which Yields Bile Salt Hydrolase from Kefir Grains

2013 ◽  
Vol 781-784 ◽  
pp. 1336-1340
Author(s):  
Hui Liu ◽  
Yuan Hong Xie ◽  
Tao Han ◽  
Hong Xing Zhang
Keyword(s):  
Bile Salt ◽  
High Throughput Screening ◽  
Bile Salts ◽  
Lactobacillus Casei ◽  
Streptococcus Thermophilus ◽  
High Yield ◽  
Bile Salt Hydrolase ◽  
Action Mechanism ◽  
Cholesterol Lowering ◽  
Conjugated Bile Salts

Cholesterol-lowering strains were obtained by high throughput screening technology and ortho-phthalaldehyde method. We used oxford cup method to screen again to obtain strains of high yield bile salt hydrolase and illuminate action mechanism ofLactobacillusreducing cholesterol. Screened six strains had the ability of high yield bile salt hydrolase and good ferment ability. The results of identifying bacteria species: strain KTxKL1J1 wereLactobacillus casei, strain Tx wasStreptococcus thermophilus, strain KS4P1 wereLactococcus lactis subsp.lactis, where the last two bacteria were strain of high yield bile salt hydrolase to be few known in literature. This work showed that dissociation bile salts and cholesterol conjuncted sediments by bile salt hydrolase decomposing conjugated bile salts.

Vectorial transport of unconjugated and conjugated bile salts by monolayers of LLC-PK1 cells doubly transfected with human NTCP and BSEP or with rat Ntcp and Bsep

2006 ◽  
Vol 290 (3) ◽  
pp. G550-G556 ◽  
Author(s):  
Sachiko Mita ◽  
Hiroshi Suzuki ◽  
Hidetaka Akita ◽  
Hisamitsu Hayashi ◽  
Reiko Onuki ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Bile Salts ◽  
Rank Order ◽  
Bile Salt Export Pump ◽  
Transcellular Transport ◽  
Physiological Conditions ◽  
System A ◽  
A Cell ◽  
Vectorial Transport ◽  
Conjugated Bile Salts

Na+-taurocholate-cotransporting peptide (NTCP)/SLC10A1 and bile salt export pump (BSEP)/ABCB11 synergistically play an important role in the transport of bile salts by the hepatocyte. In this study, we transfected human NTCP and BSEP or rat Ntcp and Bsep into LLC-PK1 cells, a cell line devoid of bile salts transporters. Transport by these cells was characterized with a focus on substrate specificity between rats and humans. The basal to apical flux of taurocholate across NTCP- and BSEP-expressing LLC-PK1 monolayers was 10 times higher than that in the opposite direction, whereas the flux across the monolayer of control and NTCP or BSEP single-expressing cells did not show any vectorial transport. The basal to apical flux of taurocholate was saturated with a Km value of 20 μM. Vectorial transcellular transport was also observed for cholate, chenodeoxycholate, ursodeoxycholate, their taurine and glycine conjugates, and taurodeoxycholate and glycodeoxycholate, whereas no transport of lithocholate was detected. To evaluate the respective functions of NTCP and BSEP and to compare them with those of rat Ntcp and Bsep, we calculated the clearance by each transporter in this system. A good correlation in the clearance of the examined bile salts (cholate, chenodeoxycholate, ursodeoxycholate, and their taurine or glycine conjugates) was observed between transport by human and that of rat transporters in terms of their rank order: for NTCP, taurine conjugates > glycine conjugates > unconjugated bile salts, and for BSEP, unconjugated bile salts and glycine conjugates > taurine conjugates. In conclusion, the substrate specificity of human and rat NTCP and BSEP appear to be very similar at least for monovalent bile salts under physiological conditions.

scholarly journals Bile Salt Hydrolase of Bifidobacterium longum—Biochemical and Genetic Characterization

2000 ◽  
Vol 66 (6) ◽  
pp. 2502-2512 ◽  
Author(s):  
Hiroshi Tanaka ◽  
Honoo Hashiba ◽  
Jan Kok ◽  
Igor Mierau
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Bile Salt ◽  
Bile Salts ◽  
Bifidobacterium Longum ◽  
Bacillus Sphaericus ◽  
Site Directed Mutagenesis ◽  
Bile Salt Hydrolase ◽  
Ph Optimum ◽  
Human Bile

ABSTRACT A bile salt hydrolase (BSH) was isolated from Bifidobacterium longum SBT2928, purified, and characterized. Furthermore, we describe for the first time cloning and analysis of the gene encoding BSH (bsh) in a member of the genusBifidobacterium. The enzyme has a native molecular weight of 125,000 to 130,000 and a subunit molecular weight of 35,024, as determined from the deduced amino acid sequence, indicating that the enzyme is a tetramer. The pH optimum of B. longum BSH is between 5 and 7, and the temperature optimum is 40°C. The enzyme is strongly inhibited by thiol enzyme inhibitors, indicating that a Cys residue is likely to be involved in the catalytic reaction. The BSH ofB. longum can hydrolyze all six major human bile salts and at least two animal bile salts. A slight preference for glycine-conjugated bile acids was detected based on both the specificity and the Km values. The nucleotide sequence of bsh was determined and used for homology studies, transcript analysis, and construction and analysis of various mutants. The levels of homology with BSH of other bacteria and with penicillin V acylase (PVA) of Bacillus sphaericus were high. On the basis of the similarity of BSH and PVA, whose crystal structure has been elucidated, BSH can be classified as an N-terminal nucleophile hydrolase with Cys as the N-terminal amino acid. This classification was confirmed by the fact that a Cys1Ala exchange by site-directed mutagenesis resulted in an inactive protein. Reverse transcription-PCR experiments revealed that bsh is part of an operon containing at least two genes, bsh andglnE (GlnE is glutamine synthetase adenylyltransferase). Two UV-induced BSH-negative mutants and one spontaneous BSH-negative mutant were isolated from B. longum SBT2928 cultures and characterized. These mutants had point mutations that inactivatedbsh by premature termination, frameshift, or amino acid exchange.

scholarly journals Metastable and equilibrium phase diagrams of unconjugated bilirubin IXα as functions of pH in model bile systems: Implications for pigment gallstone formation

2015 ◽  
Vol 308 (1) ◽  
pp. G42-G55 ◽  
Author(s):  
Marvin D. Berman ◽  
Martin C. Carey
Keyword(s):  
Phase Diagrams ◽  
Bile Salts ◽  
Cholesterol Gallstone ◽  
Equilibrium Phase ◽  
Gallstone Formation ◽  
Unconjugated Bilirubin ◽  
Ph Values ◽  
Wide Range ◽  
Pigment Gallstone ◽  
Model Bile

Metastable and equilibrium phase diagrams for unconjugated bilirubin IXα (UCB) in bile are yet to be determined for understanding the physical chemistry of pigment gallstone formation. Also, UCB is a molecule of considerable biomedical importance because it is a potent antioxidant and an inhibitor of atherogenesis. We employed principally a titrimetric approach to obtain metastable and equilibrium UCB solubilities in model bile systems composed of taurine-conjugated bile salts, egg yolk lecithin (mixed long-chain phosphatidylcholines), and cholesterol as functions of total lipid concentration, biliary pH values, and CaCl2 plus NaCl concentrations. Metastable and equilibrium precipitation pH values were obtained, and average pKa values of the two carboxyl groups of UCB were calculated. Added lecithin and increased temperature decreased UCB solubility markedly, whereas increases in bile salt concentrations and molar levels of urea augmented solubility. A wide range of NaCl and cholesterol concentrations resulted in no specific effects, whereas added CaCl2 produced large decreases in UCB solubilities at alkaline pH values only. UV-visible absorption spectra were consistent with both hydrophobic and hydrophilic interactions between UCB and bile salts that were strongly influenced by pH. Reliable literature values for UCB compositions of native gallbladder biles revealed that biles from hemolytic mice and humans with black pigment gallstones are markedly supersaturated with UCB and exhibit more acidic pH values, whereas biles from nonstone control animals and patients with cholesterol gallstone are unsaturated with UCB.

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