Degradation of 2-bromo-, 2-chloro- and 2-fluorobenzoate by Pseudomonas putida CLB 250.

Pseudomonas putida strain CLB 250 (DSM 5232) utilized 2-bromo-, 2-chloro- and 2-fluorobenzoate as sole source of carbon and energy. Degradation is suggested to be initiated by a dioxygenase liberating halide in the first catabolic step. After decarboxylation and rearomatization catechol is produced as a central metabolite which is degraded via the ortho-pathway. After inhibition of ring cleavage activities with 3-chlorocatechol, 2-chlorobenzoate was transformed to catechol in nearly stoichiometric amounts. Other ortho-substituted benzoates like anthranilate and 2-methoxybenzoate seem to be metabolized via the same route.

Iron-dependent production of a heat-modifiable, 23,000-Mr outer membrane protein in Paracoccus denitrificans.

Production of a 23,000-Mr major outer membrane protein of Paracoccus denitrificans ATCC 13543 was dependent upon the addition of iron to a succinate-salts medium. The 23,000-Mr protein was not produced in an iron-deficient medium, but production of five outer membrane proteins in the 85,000- to 72,000-Mr range and of catechol were induced. The 23,000-Mr protein was not produced in a complex medium even when ferric citrate was added to the medium. Production of the protein was influenced by the carbon source and was decreased by peptone.

Effects of chronic treatment with thyroxine and estradiol on estrogen concentration in serum and on hepatic microsomal catechol estrogen formation in female rats.

The effects of chronic treatment with thyroxine (T4) and estradiol on hepatic microsomal metabolism of estrogens to catechol products were studied and the extent to which activity in vitro correlated with serum estradiol concentrations in vivo was assessed. Female rats were treated with either estradiol benzoate (EB; 56 micrograms/kg/day from silastic implants), T4 (50 micrograms/kg/day, s.c.) or combined EB + T4 for 35 days. Animals treated with EB + T4, but not T4 alone, showed a significant increase above controls both in the concentration of triiodothyronine in serum and food consumption. Serum concentrations of endogenous estradiol in untreated control and T4-treated animals were similar. Although both EB-treated groups received comparable doses of steroid from silastic implants, the concentration of estradiol in serum was 30% lower in EB + T4-treated animals than in animals treated with EB alone. Formation of catechol estrogen metabolites by hepatic microsomes was not significantly altered by EB and T4 administered separately, but enzyme activity was increased significantly with combined hormonal therapy. In contrast, microsomal hydroxylation of testosterone was not increased by treatment with EB + T4, data which suggest that total steroid hydroxylase activity was not enhanced by combined hormonal administration. Correlation analysis of microsomal catechol estrogen formation in vitro with serum concentrations of estradiol in vivo indicated related to the concentration of estrogen in serum only after coadministration of a low dose of T4 with EB.

Synthesis of catechol estrogens by human uterus and leiomyoma.

Homogenates of human endometrial, myometrial and leiomyoma tissues were incubated with (2,4,6,7-3H)-estradiol and tritiated catechol estrogens were isolated and identified. Though 2- and 4-hydroxylations were about the same in endometrium, 4-hydroxylation was two to four fold higher than 2-hydroxylation in myometrium and leiomyoma. However, endometrium showed greater capacity to form both 2- and 4-hydroxyestrogens than the other two tissues. Both 2- and 4-hydroxylations were significantly less than in myometrium. In view of the reports indicating that inhibitors of catechol 0-methyl transferase (COMT) might act as antineoplastic agents due to their interference with t-RNA methylases and since catechol estrogens inhibit COMT, the present results suggest that endogenous synthesis of catechol estrogens may play an important role in the pathophysiology of uterine leiomyoma.

Catechol estrogen formation in placental and fetal tissues of humans, macaques, rats and rabbits.

Placental and fetal tissues obtained from humans, monkeys, rats and rabbits contained monooxygenases capable of catalyzing the formation of catechol estrogens. Treatments of pregnant rats with phenobarbital, Aroclor 1254, or 3-methylcholanthrene each increased measured rates of catechol estrogen formation in placentas, fetal brains and fetal livers, while other rat tissues exhibited either increased or decreased activity. Treatment of pregnant rabbits with Arocolor 1254 produced an increase in catechol estrogen formation in all fetal tissues studied and in the maternal liver and kidney. Catechol estrogen formation in placental microsomes of macaque monkeys (Macaca arctoides) was generally less than that observed in human placental microsomes. Human placentas obtained from smokers exhibited enhanced catechol estrogen formation and this activity appeared to be highly correlated with placental aryl hydrocarbon hydroxylase activity. The data suggested [a]pyrene in a similar fashion in placental tissues and that the enzyme systems involved may be under similar regulatory control.

[Catechol estrogens]. / Katesjolestrogene.

Hydroxylation of oestrogens in the 2 or 4 positions leads to the formation of catechol oestrogens. These compounds are physiologically active in animals, especially in the control of gonadotropin secretion. Physiological activity can be ascribed to either an oestrogenic action or interaction with the catecholaminergic systems. These compounds are also formed in human subjects. Surprisingly high levels are found in the urine. The peri-ovulatory peak in urinary catechol oestrogen excretion is compatible with a role for these compounds in the control of gonadotropin secretion.

[Enterobacterial sensitivity to colicins in the presence of enterochelin]. / Chuvstvitel'nost' énterobakterii k kolitsinam v prisutstvii énterokhelina.

The correlation between the colicine resistance of the reference and isolated strains of enterobacteria and their capacity for the biosynthesis of enterocheline, as well as the influence of exogenous enterocheline on the colicine sensitivity of enterobacteria were studied. In the wild strains of enterobacteria sensitivity to colicines was shown to have no correlation with capacity for the accumulation of catechol-type sideriphores. In some cases exogenous enterocheline prevents the lethal effect of colicines on the cultures of microorganisms capable of the biosynthesis of enterocheline.

Preferential utilization of phenol rather than glucose by Trichosporon cutaneum possessing a partially constitutive catechol 1,2-oxygenase.

A phenol-utilizing yeast, Trichosporon cutaneum POB 14, which has a partially constitutive activity of catechol 1,2-oxygenase, utilized phenol in preference to glucose in a medium containing both phenol (200 mg/liter) and glucose (0.15%) as carbon sources. The glucose consumption was not observed until the concentration of phenol decreased to around 10 mg/liter. This phenomenon was confirmed by [U-14C]glucose uptake experiments. The intracellular activities of hexokinase (EC 2.7.1.1) and catechol 1,2-oxygenase (EC 1.13.1.1) changed inversely when phenol was added during growth in the glucose medium.

[Formation of iron-binding metabolites by bacteria of the Enterobacteriaceae family]. / Obrazovanie zhelezosviazyvaiushchikh metabolitov bakteriiami semeistva Enterobacteriaceae.

The capacity of Enterobacteriaceae strains cultivated in a synthetic medium for the biosynthesis of catechols and hydroxamates has been studied. Among the strains under study all strains of the genera Salmonella (8 strains), Escherichia (102 strains), Citrobacter (5 strains), Enterobacter (2 strains), Serratia (1 strain) synthesize catechols. In the genus Shigella (128 strains) all Sh. flexneri serovars (79 strains) do not synthesize catechols, other representatives of this genus synthesize iron-fixing metabolites The synthesis of catecholsin the pathogenic Escherichia serovars is 1.5-2 times lower than in the non-pathogenic and opportunistic enterobacterial strains. Among the representatives of the genus Klebsiella (82 strains) catechols are synthesized by Kl. pneumoniae (68 strains) and not synthesized by kl. rhinoscleromatis (5 strains) and Kl. ozaenae (9 strains). Catechols are not synthesized also by all Proteus organisms under study (12 strains). All the enterobacteria under study show no capacity for the accumulation of hydroxamates under the conditions of catechol synthesis. The intensity of the synthesis of catechols depends on the composition of the medium and the conditions of cultivation.

15alpha-Hydroxyoestriol and other polar oestrogens in pregnancy monitoring.

Although oestriol measurements are well established for the assessment of 'at risk' pregnancies, there are a number of other oestrogens, excreted during pregnancy, which contain additional hydroxyl groups and might be more sensitive indicators of the condition of mother or fetus. Some of these result from the action of hydroxylases possibly present only in the fetus and others from maternal hydroxylations. We review the evidence for the biosynthesis of these polar oestrogens, summarise methods of measurement, and compare values obtained in normal and pathological pregnancies. There is as yet insufficient evidence to enable their potential value to be confirmed.

PIP: Attempts to assess "at-risk" pregnancies may be aided by measuring a number of polar estrogens excreted during pregnancy which contain additional hydroxy groups. 2 hydroxy groups show promise as sensitive indicators of maternal or fetal condition: 15-hydroxylations which appear to be predominantly fetal reactions, and 18-hydroxylations which can take place in both the fetus and adult. Excretion rates of the 15- and 18-hydroxy compounds were compared with known estriol excretion rates; in normal pregnancies the levels of estriol and 15 alpha-hydroxyestriol (15 alpha) in maternal blood and urine closely paralleled. In the pathological pregnancies, little indication that 15 alpha measurements are valuable in prediction of fetal morbidity or death was discovered; though in preeclamptic toxemia patients, 15 alpha levels became subnormal 1 day-several weeks before death, and urinary levels of 15 alpha were often low when birth weights were low. During measurement of several estriols throughout pregnancy, a good correlation between 18-hydroxyestriol and 15 alpha was shown; however, measurements from 20 at-risk pregnancies did not show such a correlation.

Suppression of amphetamine-induced hypothermia by the neutral amino acid valine.

Pretreatment with valine (0.5-2.0 mmoles/kg) can suppress the hypothermic response of rats placed in a 4degreesC environment and given d-amphetamine sulfate (5 or 10 mg/kg). The amino acid was most effective when given 30 minutes before amphetamine administration, at which time it also significantly lowered brain tyrosine concentration (and, presumably, suppressed catecholamine synthesis). Because dopaminergic neurons mediate the hypothermic response to amphetamine and because amphetamine's ability to produce hypothermia requires, in part, the release of newly synthesized dopamine, these observed effects of valine pretreatment support the hypothesis that treatments which alter precursor (tyrosine) availability also affect brain catecholamine synthesis.

Metabolism of naphthalene, 2-methylnaphthalene, salicylate, and benzoate by Pseudomonas PG: regulation of tangential pathways.

Naphthalene is metabolized by Pseudomonas PG through 1,2-dihydroxynaphthalene and salicylate to catechol, which is then degraded by the meta pathway. 2-Methylnaphthalene, but not 1-methylnaphthalene, also serves as a growth substrate and is metabolized by the same route, through 4-methylcatechol. The same nonspecific meta pathway enzymes appear to be induced by growth on either naphthalene or 2-methylnaphthalene. The level to which 2-hydroxymuconic semialdehyde hydrolase is induced is low and probably of no metabolic significance. Growth on salicylate or catechol, both intermediates of naphthalene degradation, or benzoate results in induction of the ortho pathway, the alternative route for catechol dissimilation. No induction of 1,2-dihydroxynaphthalene oxygenase was found in salicylate-grown cells. Anaerobic growth on a succinate-nitrate medium in the presence of various inducers indicates that cis, cis-muconate, or one of its metabolites is the inducer of the ortho pathway enzymes. The inducer or inducers of the early enzymes of naphthalene degradation and of the meta pathway enzymes must be an early intermediate of the naphthalene pathway above salicylate.

4-Nitrocatechol production from rho-nitrophenol by rat liver.

Time course studies of rho-nitroanisole O-demethylation revealed formaldehyde production in excess of rho-nitrophenol (PNP) and 4-nitrocatechol (NTC) formation by rat liver microsomes. This indicated that these products (PNP, NTC) were metabolised further. The hydroxylation reaction PNP yields NTC showed substrate and product inhibition and a requirement for reduced nicotinamide adenine dinucleotide phosphate and O2 and was localized in liver microsomes. It was strongly activated by ascorbic acid, cysteine, adenosine triphosphate or hydroxylamine in vitro and enhanced by phenobarbital treatment in vivo. Mercapturic derivatives were metabolized to the corresponding hydroxy compounds with the same speed as their parent compounds. Both PNP and NTC were metabolized to the corresponding glucuronide and sulfate conjugates. On the other hand, the PNP or NTC glucuronides and sulfates were metabolized with liver microsomes to PNP and NTC.

Control of salmonellosis pacifarin biosynthesis by iron.

Enterobacter cloacae strain SS4-56 produced salmonellosis pacifarins when grown in an iron-depleted synthetic medium to which 3.16 X 10-7 g-atom of iron had been added per liter, but did not do so when grown in iron-depleted medium supplemented with 3.16 X 10-4 g-atom of iron per liter. The addition of 3.16 X 10-4 g-atom of ferric iron per liter to a pacifarin-containing culture supernatant fluid had no significant effect upon the ability of the active pacifarins present, when administered per os, to protect mice from an otherwise fatal infection produced by a sequential injection of avirulent and virulent strains of Salmonella typhimurium.