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PubMed2006

S-2-pentyl-4-pentynoic hydroxamic acid and its metabolite s-2-pentyl-4-pentynoic acid in the NMRI-exencephaly-mouse model: pharmacokinetic profiles, teratogenic effects, and histone deacetylase inhibition abilities of further valproic acid hydroxamates and amides.

Structure-activity relationship studies of valproic acid (VPA) derivatives have revealed a quantitative correlation between histone deacetylase (HDAC) inhibition and induction of neural tube defects (NTDs) in the NMRI-exencephaly-mouse model, but this correlation has been, so far, limited to congeners with a carboxylic acid function. Whereas the classical HDAC inhibitor trichostatin A is active only as a hydroxamate but not as a carboxylic acid, we found that neither VPA amides nor hydroxamates inhibit HDACs, but can cause NTDs; e.g., 2-pentyl-4-pentynoic hydroxamic acid with its S-enantiomer being the potent teratogen. We therefore investigated the hypothesis that hydroxamic acid derivatives of VPA might be metabolized in vivo and may possibly be pro-teratogenic, as had been shown for valpromide but not valproic hydroxamic acid. We developed two stereoselective quantification methods based on chiral derivatization of VPA hydroxamates with (1R,2S,5R)-(-)-menthylchloroformate and carboxylic acid derivatives with (S)-(-)-1-naphthylethylamine, followed by gas chromatography-nitrogen phosphor detector analysis of biological samples. We then determined the pharmacokinetic profiles of S-2-pentyl-4-pentynoic hydroxamic acid and of S-2-pentyl-4-pentynoic acid in mice. S-2-Pentyl-4-pentynoic hydroxamic acid was found to be extensively metabolized to the corresponding carboxylic acid without affecting the stereochemistry at position C2. Furthermore, the metabolite S-2-pentyl-4-pentynoic acid was found to be very stable in vivo, with an extended half-life of 4.2 h compared with that of VPA, 1.4 h. Comparison of the individual HDAC inhibition abilities of additional VPA amides and hydroxamates, as measured by cellular and enzymatic assays, led us to the conclusion that both classes of VPA derivatives can be pro-teratogenic.

Abnormalities, Drug-Induced↗

PubMed1972

Metabolism of steroid and amino acid moieties of conjugated bile acids in man. II. Glycine-conjugated dihydroxy bile acids.

Chenodeoxycholyl-2,4-(3)H-glycine-1-(14)C and deoxycholyl-2,4-(3)H-glycine-1-(14)C were synthesized and administered orally to 10 healthy subjects. Distribution of radioactivity among bile acids and specific activity of steroid and amino acid moieties were determined in bile samples. (3)H and (14)C were measured in feces. (14)C in breath was calculated from interval (14)CO(2) specific activity determinations. The daily fractional turnover of the glycine moiety of chenodeoxycholyl and deoxycholylglycines was more than three times that of the steroid moiety. Pool size of chenodeoxycholylglycine was about twice that of deoxycholylglycine, but similar fractional turnover rates of steroid and amino acid moieties suggested that intestinal absorption of the two conjugated bile acids was equally efficient (about 95%). The amount of unlabeled deoxycholic acid (newly formed by bacterial 7alpha-dehydroxylation) absorbed from the intestine approximated 30% of the cholic acid that was lost. (3)H radioactivity remained predominantly in administered bile acid implying that, normally, secondary bile acids derived from chenodeoxycholic acid are not appreciably absorbed from the intestine and that deoxycholic acid is not hydroxylated by the liver. Approximately 25% of administered (14)C was recovered in the breath in the first 24 hr and less than 8% in the feces in 8 days; (14)CO(2) excretion correlated highly with fractional turnover of the glycine moiety. (3)H appeared predominantly in feces, and the rate of excretion correlated highly with the fractional turnover of the steroid moiety of bile acids. From the results in this paper plus previous measurements on the metabolism of cholylglycine, we calculated that about 6 mmoles/day of glycine is used for bile acid conjugation in health.

Adult↗

PubMed1991

Hepatic metabolism of short-chain bile acids. Inversion of the 3-hydroxyl group of isoetianic acid (3 beta-hydroxy-5 beta-androstane-17 beta-carboxylic acid) by the adult rat.

The stereospecificity of mechanisms for hepatic transport of short-chain bile acids has been examined by following the hepatic metabolism and biliary secretion of 3 beta-hydroxy-5 beta-androstane-17 beta-carboxylic acid (isoetianic acid) administered in two different labeled forms to rats prepared with an external biliary fistula. While 93% of the administered [2,2,4,4-3H]isoetianic acid was recovered in bile after 20 h, only 18% of a similar dose of [3 alpha-3H]isoetianic acid was secreted in bile over the same time period. The recovered radioactivity of the latter compound was mainly associated with bile water. With the [2,2,4,4-3H]isoetianic acid, the bulk of the biliary isotope was determined to be in the form of two glucuronide conjugates. Spectral analysis identified these metabolites as the hydroxyl-linked (major) and carboxyl-linked (minor) beta-glucuronides, not of the 3 beta-hydroxy compound administered, but of 3 alpha-hydroxy-5 beta-androstane-17 beta-carboxylic acid (etianic acid), i.e., the products of hydroxyl group inversion. It is concluded that isoetianic acid is efficiently cleared from plasma and conjugated with glucuronic acid after its epimerization to etianic acid. The prevalent, but not complete, loss of the 3-tritium atom and the retention of the 2- and 4-tritium atoms probably indicates a 3-oxo-5 beta-androstane-17 beta-carboxylic acid intermediate with partial return of the label via a limited labeled pool of reduced nicotinamide cofactor.

Androstanols↗

PubMed1993

Intestinal bile acid absorption. Na(+)-dependent bile acid transport activity in rabbit small intestine correlates with the coexpression of an integral 93-kDa and a peripheral 14-kDa bile acid-binding membrane protein along the duodenum-ileum axis.

The anatomical localization of the Na+/bile acid cotransport system from rabbit small intestine was determined using brush border membrane vesicles prepared from eight different segments of the small intestine. Na(+)-dependent transport activity for bile acids, both for [3H]taurocholate and [3H]cholate, was found in the distal segment 8 only representing the terminal 12% of the small intestine. In contrast, the Na(+)-dependent D-glucose transporter and the H(+)-dependent oligopeptide transporter were found over the whole length of rabbit small intestine in all segments. Photoaffinity labeling with 7,7-azo- and 3,3-azo-derivatives of taurocholate with subsequent fluorographic detection of labeled polypeptides after one- and two-dimensional gel electrophoresis showed that an integral membrane polypeptide of M(r) 87,000 is present in the entire small intestine, whereas an integral membrane protein of M(r) 93,000 together with a peripheral membrane protein of M(r) 14,000 are exclusively expressed in the distal small intestine correlating with Na(+)-dependent bile acid transport activity. Photoaffinity labeling with the cationic bile acid derivative 1-(7,7-azo-3 alpha,12 alpha-dihydroxy-5 beta[3 beta-3H]cholan-24-oyl)-1,2- diaminoethane hydrochloride and 7,7-azo-3 alpha,12 beta-dihydroxy-5 beta[12 alpha-3H]cholan-24-oic acid did not result in a specific labeling of the above mentioned proteins, demonstrating their specificity for physiological bile acids. Photoaffinity labeling of the 93- and 14-kDa bile acid-binding proteins was strongly Na(+)-dependent. Significant labeling of the 93- and 14-kDa proteins occurred only in the presence of Na+ ions with maximal labeling above 100 mM [Na+] showing a parallel [Na+] dependence to transport activity. Inactivation of Na(+)-dependent [3H]taurocholate uptake by treatment of ileal brush border membrane vesicles with 4-nitrobenzo-2-oxa-1,3-diazol chloride led to a parallel decrease in the extent of photoaffinity labeling of both the 93- and 14-kDa protein. Sequence analysis of the membrane-bound 14-kDa bile acid-binding protein surprisingly revealed its identity with gastrotropin, a hydrophobic ligand-binding protein exclusively found in the cytosol from ileocytes and thought to be involved in the intracellular transport of bile acids from the brush border membrane to the basolateral pole of the ileocyte. In conclusion, the present studies suggest that both an integral 93- and a peripheral 14-kDa membrane protein, identified as gastrotropin, and both exclusively expressed in the terminal ileum, are essential components of the Na+/bile acid cotransport system in rabbit terminal ileum.

Affinity Labels↗

PubMed1990

Influence of dietary linoleic acid and trans fatty acids on the fatty acid profile of cardiolipins in rats.

Cardiolipins (CL) have unique fatty acid profiles with generally high levels of polyunsaturated fatty acids, primarily 18:2n-6, and low levels of saturated fatty acids. In order to study the effect of dietary fatty acid isomers on the fatty acid composition of cardiolipins, rats were fed partially hydrogenated marine oils (HMO), rich in 16:1, 18:1, 20:1, and 22:1 isomeric fatty acids, supplemented with linoleic acid at levels ranging from 1.9% to 14.5% of total fat. Although the dietary fats contained 33% trans fatty acids, the levels of trans fatty acids in CL were below 2.5% in all organs. The fatty acid profiles of cardiolipins of liver, heart, kidney and testes showed different responses to dietary linoleic acid level. In liver, the contents of 18:2 reflected the dietary levels. In heart and kidney, the levels of 18:2 also paralleled increasing dietary levels, but in all groups fed HMO, levels of 18:2 were considerably higher than in the reference group fed palm oil. In testes, the 18:2 levels were unaffected by the dietary level of 18:2 and HMO.

Animals↗

PubMed1992

Effects of dietary purified eicosapentaenoic acid (20:5 (n-3)) and docosahexaenoic acid (22:6(n-3)) on fatty acid desaturation and oxidation in isolated rat liver cells.

The effects of dietary supplementation of eicosapentaenoic acid (20:5(n-3), EPA) and docosahexaenoic acid (22:6(n-3), DHA) on the metabolism of polyunsaturated fatty acids were studied in isolated rat liver cells. Both pure EPA and pure DHA and a mixture of the two n-3 fatty acids in different doses were used. The supplementation of moderate amounts of n-3 fatty acids suppressed the activity of delta 6-desaturase (50%) and to a smaller extent of the delta 5-desaturase (60-70%) compared to controls. When higher doses of dietary purified EPA and DHA were used, this inhibitory effect on the delta 6- and delta 5-desaturase activities disappeared. The delta 4-desaturase activity seemed to be unaffected by the feeding conditions used. The supplementation of the n-3 fatty acids in the diet at all dose levels used increased the beta-oxidation of all the polyunsaturated fatty acids, especially of linoleic acid, linolenic acid and eicosapentaenoic acid. The results suggest an increase both in peroxisomal and mitochondrial beta-oxidation. The peroxisomal beta-oxidation of n-3 fatty acids seemed to be particularly increased.

Animals↗

PubMed1996

Long-chain polyunsaturated fatty acid content in Dutch preterm breast milk; differences in the concentrations of docosahexaenoic acid and arachidonic acid due to length of gestation.

Recognizing the important role of long-chain polyunsaturated fatty acids (LCP) particularly in preterm infant nutrition, we studied the fatty acid composition of breast milk from 65 mothers of very preterm ( < 31 weeks of gestation) and preterm ( > or = 31 and < 36 weeks of gestation) infants. Fatty acids were determined as fatty acid methyl esters by capillary gas chromatography. In accordance with other studies, the increase of capric acid, lauric acid and myristic acid during lactation is influenced by prematurity. Unsaturated fatty acids had the inclination to decrease. Our interest was mainly focused on docosahexaenoic acid (DHA) and arachidonic acid (AA). Accelerated brain growth during the last trimester of gestation requires an extra need for these LCPs. In our study, preterm milk after a gestation period of at least 32 weeks contained the highest amounts of DHA and AA. The Western maternal diet is considered to be low in omega 3 fatty acids, that is why the concentration of DHA in our preterm milk can be regarded as a low amount. As it is the milk of their mothers, and because the amounts are higher than normally found in Western full term breast milk, the contribution of DHA to preterm milk fat (0.34%) might be considered, for the time being, as a safe natural guideline for formulas for preterm infants.

Arachidonic Acid↗

PubMed2006

Salivary uric acid at the acidic pH of the stomach is the principal defense against nitrite-derived reactive species: sparing effects of chlorogenic acid and serum albumin.

A complex antioxidant system is present in human saliva, with uric acid being the most concentrated component. Ascorbic acid, present at low concentrations in saliva, is actively secreted into the gastric lumen. We report that ascorbic acid added to human saliva at pH 2 was consumed within a few minutes, regenerating HNO(2), whereas uric acid was consumed relatively slowly in a nitrite-dependent manner. The consumption of uric acid was (i) rapid under normoxic conditions and slower at low oxygen tensions, (ii) coupled to *NO release, (iii) linked to the decrease in nitrite consumption and in nitrate formation, and (iv) unaffected by the nitrosation catalyst thiocyanate. Both chlorogenic acid and bovine serum albumin, representative of a phenol- and a protein-rich meal, respectively, were able to spare uric acid, although chlorogenic acid increased, whereas bovine serum albumin inhibited, *NO release. We hypothesize that the major role of uric acid in saliva at pH 2 could be to preserve the stomach from the formation of toxic nitrogen species and that low levels of uric acid, together with ascorbic acid consumption, may contribute to the high occurrence of tumors at the gastroesophageal junction and cardia. The sparing effects of dietary compounds may therefore be an important not fully appreciated effect.

Animals↗

PubMed2004

Cardiovascular effects of milk enriched with omega-3 polyunsaturated fatty acids, oleic acid, folic acid, and vitamins E and B6 in volunteers with mild hyperlipidemia.

OBJECTIVE: Results from epidemiologic studies and clinical trials have indicated that consumption of omega-3 fatty acids, oleic acid, and folic acid have beneficial effects on health, including decreased risk of cardiovascular disease. We evaluated the combined effects of these nutrients through the consumption of milk enriched with omega-3 polyunsaturated fatty acids, oleic acid, vitamins E and B6, and folic acid on risk factors for cardiovascular disease in volunteers with mild hyperlipidemia. METHODS: Thirty subjects ages 45 to 65 y (51.3 +/- 5.3 y) were given 500 mL/d of semi-skimmed milk for 4 wk and then 500 mL/d of the enriched milk for 8 wk. Plasma and low-density lipoproteins were obtained at the beginning of the study and at 4, 8, and 12 wk. RESULTS: Consumption of enriched milk for 8 wk increased plasma concentrations of docosahexaenoic acid and eicosapentaenoic acid and significantly (P < 0.05) decreased plasma concentrations of triacylglycerol (24%), total cholesterol (9%), and low-density lipoprotein cholesterol (13%). Plasma and low-density lipoprotein oxidation and vitamin E concentration remained unchanged throughout the study. Significant decreases in plasma concentrations of vascular cell adhesion molecule-1 (9%) and homocysteine (17%) were found, accompanied by a 98% increase in plasma concentration of folic acid. CONCLUSIONS: Dairy supplementation strategies with omega-3 polyunsaturated fatty acids, oleic acid, and vitamins may be useful for decreasing risk factors for cardiovascular disease.

Aged↗

PubMed2003

Ion-exclusion chromatographic behavior of aliphatic carboxylic acids and benzenecarboxylic acids on a sulfonated styrene--divinylbenzene co-polymer resin column with sulfuric acid containing various alcohols as eluent.

The addition of C1-C7 alcohols (methanol, ethanol, propanol, butanol, heptanol, hexanol and heptanol) to dilute sulfuric acid as eluent in ion-exclusion chromatography using a highly sulfonated styrene-divinylbenzene co-polymer resin (TSKgel SCX) in the H+ form as the stationary phase was carried out for the simultaneous separations of both (a) C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, 2-methylvaleric, isocaproic, caproic, 2,2-dimethyl-n-valeric, 2-methylhexanoic, 5-methylhexanoic and heptanoic acids) and (b) benzenecarboxylic acids (pyromellitic, hemimellitic, trimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic and salicylic acids and phenol). Heptanol was the most effective modifier in ion-exclusion chromatography for the improvement of peak shapes and a reduction in retention volumes for higher aliphatic carboxylic acids and benzenecarboxylic acids. Excellent simultaneous separation and relatively highly sensitive conductimetric detection for these C1-C7 aliphatic carboxylic acids were achieved on the TSKgel SCX column (150 x 6 mm I.D.) in 30 min using 0.5 mM sulfuric acid containing 0.025% heptanol as eluent. Excellent simultaneous separation and highly sensitive UV detection at 200 nm for these benzenecarboxylic acids were also achieved on the TSKgel SCX column in 30 min using 5 mM sulfuric acid containing 0.075% heptanol as eluent.

Alcohols↗

PubMed2002

Restoring enzyme activity in nonfunctional low erucic acid Brassica napus fatty acid elongase 1 by a single amino acid substitution.

Genomic fatty acid elongation 1 (FAE1) clones from high erucic acid (HEA) Brassica napus, Brassica rapa and Brassica oleracea, and low erucic acid (LEA) B. napus cv. Westar, were amplified by PCR and expressed in yeast cells under the control of the strong galactose-inducible promoter. As expected, yeast cells expressing the FAE1 genes from HEA Brassica spp. synthesized very long chain monounsaturated fatty acids that are not normally found in yeast, while fatty acid profiles of yeast cells expressing the FAE1 gene from LEA B. napus were identical to control yeast samples. In agreement with published findings regarding different HEA and LEA B. napus cultivars, comparison of FAE1 protein sequences from HEA and LEA Brassicaceae revealed one crucial amino acid difference: the serine residue at position 282 of the HEA FAE1 sequences is substituted by phenylalanine in LEA B. napus cv. Westar. Using site directed mutagenesis, the phenylalanine 282 residue was substituted with a serine residue in the FAE1 polypeptide from B. napus cv. Westar, the mutated gene was expressed in yeast and GC analysis revealed the presence of very long chain monounsaturated fatty acids (VLCMFAs), indicating that the elongase activity was restored in the LEA FAE1 enzyme by the single amino acid substitution. Thus, for the first time, the low erucic acid trait in canola B. napus can be attributed to a single amino acid substitution which prevents the biosynthesis of the eicosenoic and erucic acids.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗

PubMed2003

Effect of tartaric acid and dietary fibre from sun-dried raisins on colonic function and on bile acid and volatile fatty acid excretion in healthy adults.

Sun-dried raisins are a source of dietary fibre and tartaric acid. The effects of tartaric acid on colon function have not been the focus of extensive research. The purpose of the present study was to evaluate the effects of dietary fibre and tartaric acid from sun-dried raisins on colon function and on faecal bile acid and short-chain fatty acid (SCFA) excretion in healthy adults. Thirteen healthy subjects were fed 120 g sun-dried raisins/d or 5 g cream of tartar (equivalent to the tartaric acid in 120 g sun-dried raisins)/d for 9 weeks, divided into 3-week cycles. The experimental diets were fed in a crossover design after an initial control period. Faeces were collected for the last 4 d of each cycle for analysis of SCFA and bile acids. Intestinal transit time decreased from 42 h on the baseline diet to 31 h on cream of tartar (P<0.1) and to 28 h on sun-dried raisins (P<0.05). Faeces were softer on both sun-dried raisins and cream of tartar, but sun-dried raisins increased faecal wet weight (P<0.05), while cream of tartar did not. Sun-dried raisins caused significant reductions from baseline values in total bile acid concentration (from 1.42 (SD 1.03) to 1.09 (SD 0.76) mg/g, P<0.05), whereas cream of tartar did not (1.40 (SD 1.06) mg/g). Sun-dried raisins also significantly reduced the lithocholic (LC):deoxylithocholic acid (DC) ratio (from 1.63 (SD 0.85) to 1.09 (SD 0.50), P<0.02), whereas cream of tartar reduced the ratio, but to a lesser extent (1.29 (SD 0.79), NS). Both faecal bile acids and the LC:DC ratio are indicators of reduced risk for colon cancer. Sun-dried raisins increased total SCFA excretion (from 5.6 (SD 3.4) to 7.6 (SD 3.0) g/4 d, P<0.05), which remained unchanged with cream of tartar (5.6 (SD 3.0) g/4 d). Both sun-dried raisins and cream of tartar appear to be good stool softeners and to shorten intestinal transit time, although the fibre in sun-dried raisins has the added benefit of increasing faecal weight. Both sun-dried raisins and cream of tartar modulate the composition of faecal bile acids and SCFA in a way that has potential health benefits.

Adult↗

PubMed1989

Effect of dietary ascorbic acid, cholesterol and PCB on cholesterol and bile acid metabolism in a rat mutant unable to synthesize ascorbic acid.

The effect of acute or chronic ascorbic acid deficiency on the activity of hepatic cholesterol 7 alpha-hydroxylase and fecal excretion of bile acids was investigated in ODS-od/od (OD) rats (a rat mutant unable to synthesize ascorbic acid) fed a purified basal diet or purified diets containing either cholesterol (2%) or polychlorinated biphenyl (PCB) (200 mg/kg). In OD rats, the dietary requirement of ascorbic acid to maintain normal growth and normal levels of cholesterol in serum and liver is about 300 mg of ascorbic acid/kg diet. In OD rats fed the basal diet, acute or chronic ascorbic acid deficiency did not affect the activity of hepatic cholesterol 7 alpha-hydroxylase and fecal excretion of bile acids. However, in OD rats fed diets containing either cholesterol or PCB, acute ascorbic acid deficiency caused a higher level of serum cholesterol, a lower activity of hepatic cholesterol 7 alpha-hydroxylase and a lower excretion of fecal bile acids than in OD rats fed a basal diet containing an adequate level of ascrobic acid. It is concluded that acute ascorbic acid deficiency causes a hypercholesterolemia due to the depression of bile acid synthesis in OD rats fed a purified diet with cholesterol or PCB.

Animals↗

PubMed2000

Effect of a keto acid-amino acid supplement on the metabolism and renal elimination of branched-chain amino acids in patients with chronic renal insufficiency on a low protein diet.

The aim of our study was to evaluate the effect of a low-protein diet supplemented with keto acids-amino acids on renal function and urinary excretion of branched-chain amino acids (BCAA) in patients with chronic renal insufficiency (CRI). In a prospective investigation 28 patients with CRI (16 male, 12 female, aged 28-66 yrs, CCr 18.6 +/- 10.2 ml/min) on a low-protein diet (0.6 g of protein /kg BW/day and energy intake 140 kJ/kg BW/day) for a period of one month were included. Subsequently, this low protein diet was supplemented with keto acids-amino acids at a dose of 0.1 g/kg BW/day orally for a period of 3 months. Examinations performed at baseline and at the end of the follow-up period revealed significant increase in the serum levels of BCAA leucine (p < 0.02), isoleucine (p < 0.03), and valine (p < 0.02) while their renal fractional excretion declined (p < 0.02, p < 0.01 resp.). Keto acid-amino acid administration had no effect on renal function and on the clearance of inulin, para-aminohippuric acid. Endogenous creatinine and urea clearance remained unaltered. A significant correlation between fractional excretion of sodium and leucine (p < 0.05) and a hyperbolic relationship between inulin clearance and fractional excretion of BCAA (p < 0.01) were seen. Moreover, a significant decrease in proteinuria (p < 0.02), plasma urea concentration and renal urea excretion and a rise in albumin level (p < 0.03) were noted. We conclude that in patients with CRI on a low protein diet the supplementation of keto acids-amino acids does not affect renal hemodynamics, but is associated--despite increases in plasma concentrations--with a reduction of renal amino acid and protein excretion suggesting induction of alterations in the tubular transport mechanisms.

Adult↗

PubMed2004

Diversity of oleic acid, ricinoleic acid and linoleic acid conversions among Pseudomonas aeruginosa strains.

Sixteen Pseudomonas aeruginosa strains, including patent strain NRRL B-18602, three recent isolates from composted materials amended with ricinoleic acid, and 12 randomly selected from the holdings of the ARS Culture Collection, were examined for their fatty acid converting abilities. The study examined the bioconversion of oleic acid to 7,10-dihydroxy-8( E)-octadecenoic acid (DOD) and ricinoleic acid to 7,10,12-trihydroxy-8( E)-octadecenoic acid (TOD). A new DOD-like compound from linoleic acid was observed. All strains except NRRL B-247 exhibited varying levels of DOD production. NRRL B-1000, NRRL B-18602 and NRRL B-23258 with yields up to 84% were among the best DOD producers. TOD production generally paralleled DOD production at a relatively lower yield of up to 15%. Strains NRRL B-1000 and NRRL B-23260 were the best TOD producers. A DOD-like product in low yields was obtained from linoleic acid. The fatty acid bioconversion capability was related neither to growth rate nor to variation in the greenish pigmentation of the strains. Production of significant quantities of DOD and TOD from oleic and ricinoleic acids, respectively, appeared to be a characteristic trait of P. aeruginosa strains. A number of highly effective strains for DOD production were identified.

Culture Media↗

PubMed1998

Conjugated linoleic acids alter bone fatty acid composition and reduce ex vivo prostaglandin E2 biosynthesis in rats fed n-6 or n-3 fatty acids.

This study evaluated the effects of conjugated linoleic acids (CLA) on tissue fatty acid composition and ex vivo prostaglandin E2 (PGE2) production in rats given diets varying in n-6 and n-3 fatty acids. Four groups of rats were given a basal semipurified diet (AIN-93G) containing 70 g/kg of added fat for 42 d. The fat treatments were formulated to contain CLA (0 vs. 10 g/kg of diet) and n-6 (soybean oil having an n-6/n-3 ratio of 7.3) and n-3 fatty acids (menhaden oil + safflower oil having an n-6/n-3 ratio of 1.8) in different ratios in a 2 x 2 factorial design. Fatty acids in liver, serum, muscle, heart, brain, spleen, and bone (cortical, marrow, and periosteum) were analyzed by capillary gas-liquid chromatography. The various dietary lipid treatments did not affect growth; however, CLA improved feed efficiency. The CLA isomers were found in all rat tissues analyzed although their concentrations varied. Dietary CLA decreased the concentrations of 16:1n-7, 18:1, total monounsaturates and n-6 fatty acids, but increased the concentrations of n-3 fatty acids (22:5n-3 and 22:6n-3), and saturates in the tissues analyzed. Ex vivo PGE2 production in bone organ culture was decreased by n-3 fatty acids and CLA. We speculate that CLA reduced the concentration of 18:1 fatty acids by inhibiting liver delta9-desaturase activity. The fact that CLA lowered ex vivo PGE2 production in bone organ culture suggests that these conjugated fatty acids have the potential to influence bone formation and resorption.

Animal Feed↗

PubMed1997

Linoleic and alpha-linolenic acids differently modify the effects of elaidic acid on polyunsaturated fatty acid metabolism and some immune indices in rats.

To explore whether the metabolic responses to trans, compared with cis, fatty acids depend on the source of dietary polyunsaturated fatty acids (PUFA), male Sprague-Dawley rats, 5 weeks old, were fed on diets containing 30 g oleic (cis) or elaidic (trans) acids/kg in combination with either 70 g perilla oil (alpha-linolenic acid) or safflowerseed oil (linoleic acid)/kg for 3 weeks in separate experiments. The dietary fats were adjusted to have the same level of total PUFA. The dietary manipulation did not influence the growth indices, but spleen weight was greater when the dietary PUFA source was perilla oil. The incorporation of trans fatty acid into liver phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine and adipose tissue lipids, particularly phospholipids, was significantly higher when rats were fed on safflowerseed oil compared with perilla oil. However, only limited differences were observed in the effects of cis and trans fatty acids on the proportions of PUFA in liver phospholipids. Splenic production of prostaglandin E2 was reduced by trans fatty acid when safflowerseed oil was the PUFA source, but no trans effect was observed on leukotriene C4 production. Dietary PUFA significantly influenced the concentration of plasma immunoglobulins (Ig) but the effect of geometry was only seen in IgG which was increased by trans acid. Dietary trans fatty acid increased the CD4+:CD8+ T-lymphocyte ratio in the spleen, reflecting a decreasing trend of the proportion of CD8+, when combined with perilla oil. These observations indicate that the type of PUFA simultaneously ingested specifically influences the effect that trans acid exerts on PUFA metabolism, eicosanoid production and some immune indices.

Animals↗

PubMed1998

Different bile acids exhibit distinct biological effects: the tumor promoter deoxycholic acid induces apoptosis and the chemopreventive agent ursodeoxycholic acid inhibits cell proliferation.

Epidemiological studies have suggested that the concentration and composition of fecal bile acids are important determining factors in the etiology of colon cancer. However, the mechanism by which these compounds influence tumor development is not understood. To begin to elucidate their mechanism of action, four bile acids, cholic acid, chenodeoxycholic acid, deoxycholic acid (DCA), and ursodeoxycholic acid, were examined for their effects on the growth of several different tumor cell lines. We found that incubating cells with chenodeoxycholic acid or DCA caused morphological changes, seen by electron and light microscopy, that were characteristic of apoptosis, whereas incubating cells with ursodeoxycholic acid inhibited cell proliferation but did not induce apoptosis. Cholic acid had no discernible effect on cells. Notably, the apoptosis induced by DCA could be suppressed by inhibiting protein kinase C activity with calphostin C. These results indicate that different bile acids exhibit distinct biological activities and suggest that the cytotoxicity reported for DCA may be due to its capacity to induce apoptosis via a protein kinase C-dependent signaling pathway.

Anticarcinogenic Agents↗