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PubMed1992

Biotransformation in carcinogen-induced diploid and polyploid hepatocytes separated by centrifugal elutriation.

Biotransformation in carcinogen-induced diploid and polyploid hepatocytes was studied using isozyme-selective substrates for several enzyme pathways. Diploid hepatocytes were induced by partial hepatectomy, a single injection of diethylnitrosamine, and 4 weeks of 2-acetylaminofluorene (2-AAF) feeding. Then, after an additional 3-5 weeks on the control diet, diploid and polyploid hepatocytes were separated from freshly isolated hepatocytes by centrifugal elutriation. Benzo(a)pyrene hydroxylase, ethoxyresorufin O-deethylase, and methoxycoumarin O-demethylase activities were approximately 15-40% lower in the diploid hepatocyte fraction than in the polyploid cell fraction. Activities of 1-chloro-2,4-dinitrobenzene, glutathione S-transferase, 3-hydroxy-benzo(a)pyrene or 4-hydroxybiphenyl UDP-glucuronosyltransferase, and DT-diaphorase were not different in the two cell fractions. Determination of activity during the 2-AAF treatment indicated that 2-AAF increased 7-ethoxyresorufin O-deethylase and 3-hydroxybenzo(a)pyrene glucuronosyltransferase activities by 300 and 200%, respectively, in both the diploid and polyploid hepatocyte fractions. Administration of phenobarbital for 4 days at the end of the control diet period increased ethoxyresorufin and methoxycoumarin dealkylations by 2- and 4-fold, and 3-hydroxybenzo(a)pyrene glucuronidation and 1-chloro-2,4-dinitrobenzene conjugation with glutathione by 1.5- to 2-fold in both hepatocyte fractions. Slight increases in benzo(a)pyrene hydroxylation and 4-hydroxybiphenyl glucuronidation were also evident in diploid cells. Although there is a slight decrease in cytochrome P-450-dependent monooxygenase activities, these data indicate that carcinogen-induced diploid hepatocytes do not show the typical toxicant-resistant phenotype observed in preneoplastic hepatocytes of altered liver foci, which are characterized by large decreases in monooxygenase biotransformations as well as increased activities of several phase II enzymes. This finding is compatible with the hypothesis that 2-AAF-induced nonploidizing growth of diploid hepatocytes is caused by nontoxic mechanisms in the present experimental paradigm. In addition, carcinogen-induced diploid cells respond to phenobarbital in a manner similar to that of polyploid hepatocytes.

2-Acetylaminofluorene↗
PubMed1986

Effects of chronic ethanol consumption on benzo(a)pyrene metabolism and glutathione S-transferase activities in Syrian golden hamster cheek pouch and liver.

The metabolism of benzo(a)pyrene (BaP) by hepatic or cheek pouch epithelium microsomes obtained from Syrian golden hamsters which had been consuming an ethanol-containing liquid diet for 4 wk and from pair-fed controls was measured. Glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene or (+/-)-r-7,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene as substrates was measured in cytosol obtained from the liver or cheek pouch epithelium of the same animals. Cytosolic hepatic glutathione levels were measured in both ethanol-consuming and control animals. The metabolism of BaP to 4,5-dihydro-4,5-dihydroxybenzo(a)pyrene (BaP-4,5-diol), 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene (BaP-7,8-diol), 9-hydroxybenzo(a)pyrene (9-OH-BaP), and 3-hydroxybenzo(a)pyrene (3-OH-BaP) by hepatic microsomes from ethanol-consuming hamsters was significantly reduced (40-52%) (P less than 0.05) compared to control microsomes. However, a 2-fold increase (P less than 0.05) in the metabolism of BaP to BaP-7,8-diol and 9,10-dihydro-9,10-dihydroxybenzo(a)pyrene was measured with microsomes from the cheek pouch epithelium of ethanol-consuming animals. There was no significant change in the production of BaP-4,5-diol, 9-OH-BaP, or 3-OH-BaP by cheek pouch epithelium microsomes of ethanol-consuming hamsters compared to controls. No difference in glutathione S-transferase activity of hepatic or cheek pouch epithelium cytosol between control and ethanol-consuming hamsters towards 1-chloro-2,4-dinitrobenzene or (+/-)-r-7,t-8-dihydroxy-t-9,10- epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene was observed. Hepatic glutathione content was significantly (P less than 0.05) decreased after 2 wk (23%) and 4 wk (33%) of ethanol consumption. The results suggest a mechanism by which ethanol might enhance BaP tumorigenesis in the hamster cheek pouch.

Alcoholism↗
PubMed1979

Importance of conjugation reactions in determining the qualitative nature of polycyclic aromatic hydrocarbon-DNA interactions.

Polycyclic aromatic hydrocarbons are metabolically activated by microsomal enzymes to reactive metabolites which covalently bind to DNA. The qualitative and quantitative nature of the hydrocarbon-deoxyribonucleoside adducts formed are markedly dependent on the balance of the oxidative and conjugating enzymes present in the activation system. Thus, utilising rat liver microsomes, to metabolically activate benzo(a)pyrene, the major hydrocarbon-deoxyribonucleoside adduct formed is due to metabolic activation of 9-hydroxybenzo(a)pyrene. In striking contrast to this when isolated rat hepatocytes are used to metabolically activate [3H]-benzo(a)pyrene, 9-hydroxybenzo(a)pyrene is conjugated primarily with UDPglucuronic acid and the major hydrocarbon-deoxyribonucleoside adduct formed is due to further metabolism of 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene. Thus the balance and nature of conjugating enzymes present in a tissue will, by determining the nature and amounts of adducts formed, also modulate the biological susceptibility of a particular tissue or cell. In this regard it may be of particular interest that whereas in isolated rat hepatocytes and short-term organ cultures of rodent lung and trachea conjugation with UDPglucuronic acid is quantitatively the major route of conjugation, with short-term organ culture of human lung, sulphate ester conjugation of phenolic substrates appears to be a major route of metabolism. Thus in vivo or in microsome or cell mediated mutagenesis assays of polycyclic aromatic hydrocarbons the susceptibility of a particular cell or tissue will be dependent in part on the relative activities of the oxidative and conjugating enzymes.

Animals↗
PubMed1979

[Intolerance to acetylsalicylacid and food additives in patients suffering from recurrent urticaria (author's transl)].

Ninety patients suffering from recurrent urticaria were orally exposed to 500 mg acetyl salicylic acid (ASA). 36.6% proved to be ASA intolerant in this group. 26 ASA-positive and 18 ASA-negative probands were selected to take part in an additional provocation test with 8 different food additives (preservative and colouring matters). Altogether 31 tests sheets were exaluated. Urticarial reactions were seen after administration of p-hydroxybenzoic acid methylester (5), p-hydroxybenzoic acid propylester (6), benzoic acid (9), sodium benzoate (6), tartrazine (6). Ponceau rouge (5) and indigo carmine (3). Detailed research was carried out on the occurrence of the tested substances. With a diet avoiding salicylates, benzoates and colouring matter 20% of these patients recovered spontaneously and became symptom-free, whilst a further 55% of cases showed marked improvement.

Adult↗
PubMed1984

Comparative benzo[a]pyrene metabolite patterns in fish and rodents.

Benzo[a]pyrene is converted to 3-hydroxybenzo[a]pyrene, 9-hydroxybenzo[a]pyrene, benzo[a]pyrene-4,5-dihydrodiol, benzo[a]pyrene-7,8-dihydrodiol, benzo[a]pyrene-9,10-dihydrodiol, and benzo[a]pyrene quinones by postmitochondrial supernatant or microsomes in such fish as the rainbow trout, flounder, salmon, mullet, little skate, Fundulus grandis, and sea catfish. It is also now well-established that many fish convert benzo[a]pyrene to potent mutagenic metabolites as has been demonstrated with the Ames test, especially when the fish are induced with Aroclor 1254 or 3-methylcholanthrene. The metabolite patterns obtained at different substrate concentrations levels indicate that the metabolism is more complex at low concentrations when metabolites are recycled in the in vitro system.

Animals↗
PubMed1984

Acyl pentapeptide lactone synthesis in actinomycin-producing streptomycetes by feeding with structural analogs of 4-methyl-3-hydroxyanthranilic acid.

Several structural analogs of 4-methyl-3-hydroxyanthranilic acid (4-MHA) that had been established as substrates of the 4-MHA-activating enzyme from Streptomyces chrysomallus (Keller, U., Kleinkauf, H., and Zocher, R. (1984) Biochemistry 23, 1479-1484) were fed in short term labeling experiments to cultures of two actinomycin-producing streptomycetes. Besides inhibition of actinomycin synthesis, the addition of 4-methyl-3-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-aminobenzoic acid, or 4-methyl-3-methoxy-benzoic acid induced the formation of novel compounds. The data indicate that these compounds are structural analogs of 4-MHA pentapeptide lactones, which are the most probable precursors of actinomycins (Katz, E. (1967) in Antibiotics II (Gottlieb, D., and Shaw, P. D., eds) pp. 276-341, Springer-Verlag, New York). Since the structural analogs of 4-MHA are missing the o-aminophenol configuration, the corresponding acyl pentapeptide lactones cannot react with each other to give phenoxazines. Therefore, they accumulate and thus become detectable. Feeding cultures with 4-MHA resulted in an inhibition of actinomycin synthesis apparently at the level of acyl pentapeptide lactone synthesis. In such experiments, the formation of pentapeptide lactones, which are most likely derived from 4-MHA pentapeptide lactones, could be detected. The results provide experimental evidence that the biosynthesis of actinomycins proceeds via the 4-MHA-pentapeptide lactones.

Amino Acids↗
PubMed1981

Identification of cocarcinogens and their potential mechanisms of action using C3H10T 1/2 CL8 mouse embryo fibroblasts.

The cocarcinogenic action of five agents which increase microsomal mixed-function oxidase activity in vivo was examined in the C3H10T 1/2 CL8 transformation assay. The compounds studied were benz(a)anthracene, 5,6-benzoflavone, phenobarbital, pregnenolone-16 alpha-carbonitrile, and Aroclor 1254. After a 48-hr pretreatment with the agent, the cells were then treated with benzo(a)pyrene [B(a)P] and the agent for an additional 24 hr. All agents except for Aroclor 1254 increased B(a)P-mediated transformation in C3H10T 1/2 CL8 cells. Benz(a)anthracene, 5,6-benzoflavone, phenobarbital, and pregnenolone-16 alpha-carbonitrile also increased the overall metabolism of B(a)P in C3H10T 1/2 CL8 cells to 9,10-dihydro-9,10-dihydroxybenzo(a)pyrene; 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene, 9-hydroxybenzo(a)pyrene, and 3-hydroxybenzo(a)pyrene. Growth studies indicated that all four agents had no stimulatory effect which might have explained the increases in transformation frequency. This suggests that these agents exert their cocarcinogenic action via increases in the enzyme-mediated pathways of B(a)P metabolism.

Animals↗
PubMed1981

Relationship between benzo(a)pyrene-induced DNA base modification and frequency of reverse mutations in mutant strains of Salmonella typhimurium.

Salmonella typhimurium cells (TA98 and TA100) were incubated with [3H]benzo(a)pyrene ([3H]BP) and induced rat liver microsomes. The BP-induced cytotoxicity and His+ reverse-mutation frequencies were determined, and bacterial DNA hydrolysates were chromatographed on Sephadex LH-20. Analysis indicated three principal DNA adducts formed from two diastereoisomeric BP diol-epoxides and a 9-hydroxy-benzo(a)pyrene metabolite. An 8.6-fold increase in TA100 cell concentration in the microsome incubation was paralleled by a 7.2-fold decrease in total adducts per cell and a 7.4-fold decrease in mutation frequency. Separate TA98 incubations were titrated with increasing concentrations of [3H](+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene ([3H]anti BP diol-epoxide), [3H](+/-)-7 beta, 8 alpha-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene [3H]syn BP diol-epoxide), or [3H]9-hydroxybenzo(a)pyrene. Linear, nonsaturated increases in DNA adduct levels were seen up to the highest observed concentrations of 4.00 microM BP diol-epoxide or 6.00 microM 9-hydroxybenzo(a)pyrene in both TA98 and TA100 cells. The increasing adduct levels were accompanied by linearly increasing mutation frequencies. At equivalent concentrations of the two DP diol-epoxides, an average of 8.2-fold more base substitution mutations (TA100) were seen than frameshift mutations (TA98). The results also indicate significant differences in absolute mutagenic efficiency (mutation frequency/unit modified DNA) between these three covalent DNA ligands (TA98, syn BP diolepoxide greater than 9-hydroxy-4,5-epoxy-benzo(a)pyrene greater than anti BP diol-epoxide; TA100, 9-hydroxy-4,5-epoxy-benzo(a)pyrene greater than syn BP diol-epoxide greater than anti BP diol-epoxide).

Animals↗
PubMed1981

Colorimetry of angiotensin-I converting enzyme activity in serum.

This simple, accurate, and reproducible colorimetric method for determining the activity of angiotensin-I converting enzyme is based upon colorimetry of the quinoneimine dye produced from the substrate p-hydroxyhippuryl-L-histidyl-L-leucine by action of this enzyme through the following series of reactions. The enzyme acts on the substrate to yield p-hydroxyhippuric acid and L-histidyl-L-leucine. The former is then hydrolyzed in the presence of hippuricase to produce p-hydroxybenzoic acid and glycine. Finally, oxidative coupling of p-hydroxybenzoic acid with 4-aminoantipyrine is catalyzed by peroxidase in the presence of hydrogen peroxide, producing a quinoneimine dye, the concentration of which is measured at its absorbance maximum at 505 nm to evaluate the activity of ACE. The Km value for the above-mentioned substrate is 0.32 mmol/L, the optimum pH is 8.3. Results by the present method and Cushman and Cheung's method (Biochem. Pharmacol. 20: 1637, 1971) correlate closely (r = 0.986). The within-run CV is 2.93%.

Colorimetry↗
PubMed1982

Metabolic activation of benzo(a)pyrene by transformable and nontransformable C3H mouse fibroblasts in culture.

Incubation of 2.5 microM benzo(a)pyrene (BaP) with C3H/10T 1/2 or CVP3SC6 (CVP) mouse fibroblasts for 48 hr resulted in the metabolism of 36 to 42% of the BaP to organic soluble derivatives, which cochromatographed with 7,8-trans-dihydroxy-7,8-dihydrobenzo(a)pyrene, 9,10-trans-dihydroxy-9,10-dihydrobenzo(a)pyrene, 3-hydroxybenzo(a)pyrene, and 9-hydroxybenzo(a)pyrene, or to water-soluble derivatives. The formation of both organic and water-soluble metabolites during the 48-hr period increased proportionally with time, except in the case of BaP phenols, which increased initially but then remained the same or decreased. The distribution of organic soluble metabolites in the extracellular culture medium consisted primarily of BaP diols and was significantly different from that found inside the cells. The intracellular profile of organic soluble metabolites produced by both cell lines consisted predominantly of BaP phenolic derivatives and was qualitatively similar to the spectrum of metabolites produced by the incubation of BaP with C3H/10T 1/2 or CVP cell microsomes. The nature of the BaP water-soluble derivatives produced by the C3H/10T 1/2 and CVP cell lines was investigated by hydrolysis of culture medium with beta-glucuronidase and arylsulfatase. Although sulfation was not a major conjugation pathway for BaP in these cells, glucuronidation of BaP phenols was found to account for 30% of the total water-soluble derivatives. The similarity in the kinetics and qualitative nature of the metabolism of BaP by C3H/10T 1/2 and CVP cells indicates that both cell lines are equally capable of biosynthesizing the proximal carcinogen, 7,8-trans-dihydroxy-7,8-dihydrobenzo(a)pyrene. Analysis of the water-soluble metabolites produced by these cells suggests further that the nonresponsiveness of the CVP cells to BaP-induced transformation cannot be accounted for on the basis of an increased detoxication of 7,8-trans-dihydroxy-7,8-dihydrobenzo(a)pyrene.

Animals↗
PubMed1984

Effects of butylated hydroxyanisole on the metabolism of benzo(a)pyrene by mouse lung microsomes.

Butylated hydroxyanisole (BHA) is a commonly used food additive with demonstrated inhibitory action against chemical carcinogenesis in animals. In order to elucidate the mechanism of the anticarcinogenic action, the effects of BHA on benzo(a)pyrene (BP) metabolism were studied with lung microsomes from female mice. BHA treatment (0.5% in the diet for 7 days) inhibited BP metabolism and altered the ratios among different metabolites as analyzed by high-performance liquid chromatography. The treatment reduced the metabolic formation of 9,10-dihydroxy-9,10-dihydrobenzo(a)pyrene, but not the production of 3-hydroxybenzo(a)pyrene and trans-4,5-dihydroxy-4,5-dihydrobenzo(a)pyrene. Since the gross microsomal cytochrome P-450 content was not significantly affected by the treatment, the change of regioselectivity in BP metabolism was probably due to the alteration of cytochrome P-450 isozyme composition by dietary BHA. General and regioselective inhibition of BP metabolism was also observed when BHA was added to the lung microsomal incubation mixture. The formation of 9,10-dihydroxy-9,10-dihydrobenzo(a)pyrene and 9-hydroxybenzo-(a)pyrene was inhibited more severely than that of trans-4,5-dihydroxy-4,5-dihydrobenzo(a)pyrene and trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene, but the production of 3-hydroxy-benzo(a)pyrene was not inhibited. Dietary BHA treatment also decreased the microsomal metabolism of trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene to n-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo(a)pyrene and r-7,t-8-dihydroxy-c-9,10-oxy-7,8,9,10-tetrahydrobenzo(a)pyrene. Considering that the former diol-epoxide is a suspected ultimate carcinogen, the observed inhibitions of BP metabolism in the formation of diol-epoxides may be closely related to the anticarcinogenic action of BHA.

Animals↗
PubMed1980

Benzo(a)pyrene metabolism in bovine aortic endothelial and bovine lung fibroblast-like cell cultures.

The metabolism of [3H]benzo(a)pyrene ([3H]BP) in bovine aortic endothelial and bovine lung fibroblast-like cells in vitro was investigated. Both cell types metabolized BP to organic solvent-extractable and water-soluble metabolites. The major organic solvent-extractable metabolites were 9-hydroxy-benzo(a)pyrene and 3-hydroxybenzo(a)pyrene; 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene, 9,10-dihydro-9,10-dihydroxy-benzo(a)pyrene, and BP quinones were also formed. No glucuronide or sulfate conjugates of BP metabolites were detected. When exposed to [3H]-3-hydroxybenzo(a)pyrene, both cell types metabolized this phenol to water-soluble derivatives, probably through oxidation rather than conjugation of the molecule. These results demonstrate that endothelial cells metabolze BP to a proximate carcinogenic derivative, the 7,8-dihydrodiaol. Thus, efforts to predict the biological effects of hydrocarbons of an organism must take into account possible metabolic activation by endothelial cells as well as by other target tissues. The formation of unconjugated, phenolic hydrocarbon derivatives by bovine cells suggests their use as a model system for studying the contribution of phenols to the induction of biological effects by hydrocarbons.

Animals↗
PubMedDate not supplied

[Utilization of aromatic compounds by yeasts of the genus Debaryomyces].

The ability to utilize phenol, catechol, resorcinol, hydroquinone, p-hydroxybenzoic acid, m-hydroxybenzoic acid, 2,4-dihydroxydenzoic acid, protocatechuic and gentisic acids was studied among 61 strains of 23 yeast species belonging to the Debaryomyces genus. All species characterized by active fermentation did not utilize these aromatic compounds. If fermentation was absent or weak, some of the aromatic compounds were utilized. This fact suggests an ecological difference between the two above yeast groups, justifying the subdivision of the Debaryomyces genus by some authors into two genera Debaryomyces and Torulaspora. No correlation could be established between the utilization of certain aromatic compounds and the yeast species classified on the basis of their behaviour toward carbohydrates. Therefore, classification of yeasts belonging to the Debaryomyces genus is artificial. It would be expedient to isolate a small number of typical species unless a more accurate relationship is established between cultures of the Debaryomyces genus referred to as different species.

Ascomycota↗
PubMed1994

Novel pathway for bacterial metabolism of bisphenol A. Rearrangements and stilbene cleavage in bisphenol A metabolism.

Bisphenol A (BPA) is metabolized by a Gram-negative aerobic bacterium via a novel pathway involving oxidative skeletal rearrangement of the BPA. Oxidation of the aliphatic methyl group of BPA leads to coproduction of the methyl-hyroxylated 2,2-bis(4-hydroxyphenyl)-1-propanol and a skeletally rearranged triol 1,2-bis(4-hydroxyphenyl)-2-propanol. The major route of metabolism (> 80%) is through the rearrangement. The 1,2-bis(4-hydroxyphenyl)-2-propanol is dehydrated to 4,4'-dihydroxy-alpha-methylstilbene, which is rapidly cleaved by oxidation to 4-hydroxybenzaldehyde and 4-hydroxyacetophenone. 4-Hydroxybenzaldehyde is oxidized to 4-hydroxybenzoic acid. Both 4-hydroxybenzoic acid and 4-hydroxyacetophenone are mineralized. The minor product of BPA hydroxylation, 2,2-bis(4-hydroxyphenyl)-1-propanol, is further oxidized to form both 2,2-bis(4-hydroxyphenyl)propanoic acid and a skeletally rearranged tetraol, 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. As is the case in the hydroxylation of BPA, the major product is skeletally rearranged. 2,3-Bis(4-hydroxyphenyl)-1,2-propanediol is slowly transformed to 4-hydroxyphenacyl alcohol.

1-Propanol↗
PubMed1993

Biosynthesis of ubiquinone and plastoquinone in the endoplasmic reticulum-Golgi membranes of spinach leaves.

The localization of ubiquinone (UQ) and plastoquinone (PQ) biosynthesis in subfractions isolated from spinach leaves has been studied. UQ-9 and UQ-10 were found mainly in mitochondria, whereas PQ was enriched in chloroplasts, but also found in Golgi membranes. alpha-Unsaturated polyprenol-11 was also present at a low concentration in chloroplasts. Autoradiography revealed the presence of nonaprenyl-4-hydroxybenzoate (NPHB) and nonaprenyl-2-methylquinol (NPMQ) transferase activities involved in quinone biosynthesis in all subfractions, but the specific activities involved in quinone biosynthesis in the total microsomal fraction were 20 times higher than those in mitochondria and chloroplasts. The isolated Golgi vesicles were particularly enriched in both activities. When the incubation medium containing total microsomes or Golgi membranes was supplemented with NADH, NADPH, S-adenosylmethionine, and an ATP-generating system, NPHB and NPMQ were transferred to UQ-9 and PQ, respectively. trans-Prenyltransferase, which synthesizes the side chain of UQ and PQ, was present in the total microsomal fraction. With farnesyl-PP as substrate, no product was formed, but with geranyl-PP, solanesyl-PP was synthesized and transferred to 4-hydroxybenzoate present in the total microsomal fraction. The results show that these membranes from spinach contain farnesyl-PP synthetase. It is concluded that the plant leaf Golgi membranes contain the enzymes for both UQ and PQ biosynthesis and that a specific transport and targeting system is required for selective transfer of UQ to the mitochondria and of PQ to the chloroplast.

Cell Fractionation↗
PubMed1977

Epidermal hyperplasia after topical application of benzo (a) pyrene, benzo (a) pyrene diol epoxides, and other metabolites.

The effects of benzo(a)pyrene (BP) and 22 derivatives upon the number of nuclei per unit length of epidermis, the number of cell layers of epidermis, and the thickness of the epidermal layer were studied. Several derivatives of BP induced changes in epidermal morphology that are typical of those produced by various agents that promote skin tumorigenesis after application of an initiator. The most potent compounds tested were the BP diol epoxides, (+/-)-7beta,8alpha-dihydroxy-9beta, 10beta-epoxy-7,8,9,10-tetrahydrobenzo-(a)pyrene (diol epoxide 1) and (+/-)-7beta,8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (diol epoxide 2). These derivatives were followed in activity by 9-hydroxybenzo(a)pyrene, 2-hydroxybenzo(a)pyrene, and by 9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene. The possible implications of these results with regard to the carcinogenicity of BP on mouse skin are discussed.

Administration, Topical↗
PubMedDate not supplied

Analysis of glycolysis metabolites by capillary zone electrophoresis with indirect UV detection.

The glycolysis metabolites glucose 6-phosphate (G6-P), fructose 6-phosphate (F6-P), fructose 1,6-bisphosphate (F1,6-BP), fructose 2,6-bisphosphate (F2,6-BP), glyceraldehyde phosphate (GAP), dihydroxyacetone phosphate (DHAP), phosphoenolpyruvate (PEP), pyruvate, and lactate were analyzed by capillary zone electrophoresis (CZE) with indirect UV detection. The chromophores phthalic acid, sorbic acid, and 4-hydroxybenzoic acid were studied as background electrolytes. Both detection sensitivity and resolution were found to depend on the pH and the concentration of the carrier electrolyte. Optimum separation and detection of the phosphate compounds were accomplished upon reversal of electroendosmotic flow (EOF) with OFM Anion-BT (Waters Corp., Milford, MA) at a concentration of 4-6 mM 4-hydroxybenzoic acid, pH 11.6-12.0, with the detection wave-length set at 280 nm. The highly alkaline pH allowed the successful separation of the isomers F6-P and G6-P, as well as F1,6-BP and F2,6-BP, respectively. The effect of sample ionic strength on the detection limits of G6-P, F6-P, F1,6-BP, and F2,6-BP was also investigated: These limits ranged from 1 to 3 microM in both low- and high-ionic-strength samples. However, high Mg2+ concentrations in the sample led to a progressive loss of resolution between F1,6-BP and F2,6-BP, unless the inlet reservoir was replenished with fresh electrolyte after every injection. Linearity of detection was observed over one to two orders of magnitude.

Dihydroxyacetone Phosphate↗
PubMed1998

Penicillium expansum growth and production of patulin in the presence of benzoic acid and its derivatives.

This study was conducted in order to evaluate the influence of benzoic acid and its derivatives: o-nitrobenzoic acid, o- and p-aminobenzoic acids, o-hydroxybenzoic acid, acetylsalicylic acid, cinnamic acid and aldehyde, methyl and ethyl esters of benzoic acid, methyl ester of p-hydroxybenzoic acid and ethyl ester of p-aminobenzoic acid on the growth and the ability to produce patulin by Penicillium expansum. The growth of the mycelium and its ability to produce patulin in the liquid enriched Czapek medium, and the dynamics of its linear growth and sporulation, on the Sabouraud medium with addition of the above mentioned compounds were evaluated. Benzoic acid and most of its derivatives, within the studied range of concentrations, limited the growth of the microfungus, while methyl ester of benzoic acid and o-aminobenzoic acid stimulated its growth.

Benzoates↗