Medium for Assay of Vitamins with Lactic Acid Bacteria

Flynn, Laura M.; Williams, V. B.; O’Dell, Boyd L.; Hogan, A. G.

doi:10.1021/ac60049a037

Cited by 81 publications

(24 citation statements)

References 21 publications

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“…Microbial Inhibition.-The inhibitory activities of the reduced analogues of aminopterin were determined for two organisms, Streptococcus faecalis (8043) and Pediococcus cerevisiae (8081); either solid medium (Burchenal et al, 1952) or the usual tube assay technique (Flynn et al, 1951) was used. In the latter case the solutions of the analogues were added aseptically to the autoclaved media.…”

Section: Fig 1-ultraviolet Spectra Of Dihydroaminop-mentioning

confidence: 99%

Preparation and Biological Activity of Dihydroaminopterin^*

Zakrzewski¹,

Hakala²,

Nichol³

1962

Biochemistry

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Section: Fig 1-ultraviolet Spectra Of Dihydroaminop-mentioning

confidence: 99%

Preparation and Biological Activity of Dihydroaminopterin^*

Zakrzewski¹,

Hakala²,

Nichol³

1962

Biochemistry

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“…It is one of the lactic acid bacteria that requires folic acid and is widely used for folic acid and FAA assay (15,27). A fastidious organism, requiring a relatively complex medium (9), it cannot synthesize folic acid from simple precursors. The requirement for folic acid also can be met by providing pteroic acid, a reduced folate, or the products of the folate pathway (20).…”

Section: Mutagenic Studies Of Folic Acid Antagonistsmentioning

confidence: 99%

“…The requirement for folic acid also can be met by providing pteroic acid, a reduced folate, or the products of the folate pathway (20). The organism is a microaerophilic coccus (27) The medium used was the standard folic acid assay medium as described by Flynn et al (9), with the exception that glucose and folic acid were sterilized separately and added aseptically at the time of the test. This is a semisynthetic medium containing acid-hydrolyzed casein, a vitamin mixture, and purines.…”

Section: Mutagenic Studies Of Folic Acid Antagonistsmentioning

confidence: 99%

Mutagenic Studies of Folic Acid Antagonists

Genther

Schoeny

Loper

et al. 1977

Antimicrob Agents Chemother

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Compounds that compete with folic acid (folic acid antagonists [FAAs]) become limited in their usefulness in the treatment of leukemia, malaria, and bacterial infections by the rapid development of resistance. Assays of the plasma levels of certain of these FAAs led to the observation, in about 25% of the determinations, that a higher density of growth of Streptococcus faecium var. durans (ATCC 8043) was obtained at an FAA concentration just below the completely inhibitory level than at one-half this concentration. This and other considerations suggested that FAAs may act not only as selective agents for resistant organisms but also as mutagens. Seven FAAs including amethopterin, pyrimethamine, trimethoprim, chlorguanide triazine, an experimental quinazoline, WR-158,122, and two experimental triazines, WR-99,210 and WR-38,839, were tested for mutagenicity in the Salmonella reversion assay developed by Ames et al. (1975). All were found to be negative for strains TA1535, TA1537, TA1538, TA98, and TA100, both with and without microsomal activation. These compounds were then tested as mutagens for three traits in the folic acid-requiring S. faecium . FAAs were shown to cause mutations to folic acid independence, rifampin resistance, and FAA resistance. It is postulated that the FAAs induce mutations by causing thymine deprivation in the folic acid-requiring host.

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“…For enzyme production, the growth medium for SKI-CF/6 contained 0.3% sodium ammonium phosphate instead of leucovorin. For the Flavobacterium sp., basal medium was supplemented with 0.3% sodium citrate, 1.0% yeast extract, and the following vitamins (in micrograms per milliliter [14]): biotin, 0.01; thiamine, 0.2; calcium pantothenate and nicotinic acid, each at 0.4; p-aminobenzoic acid and riboflavin, each at 0.5; and pyridoxine and pyridoxal, each at 1.…”

mentioning

confidence: 99%

Carboxypeptidase displaying differential velocity in hydrolysis of methotrexate, 5-methyltetrahydrofolic acid, and leucovorin

Albrecht¹,

Boldizsar²,

Hutchison³

1978

J Bacteriol

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An enzyme that catalyzes the hydrolysis of folic acid and the antifolate methotrexate nearly 20 times more rapidly than the hydrolysis of 5-methyltetrahydrofolate was extracted from a gram-negative bacterium tentatively identified as a Flavobacterium sp. The enzyme was purified 500-fold and found to have a molecular weight of about 53,000. Apparently a metallo-enzyme, it is inhibited by citrate and ethylenediaminetetraacetic acid (EDTA). Ca2+, Co2+, Mg2+, and Zn2+ reverse inhibition by EDTA, whereas Ca2+ and Zn2+ are weak activators in the absence of EDTA. The enzymatic reaction releases the carboxy-terminal glutamyl moiety of derivatives of pteroyl-mono-L-glutamic acid. Substituents on N5 of the pteridine ring decrease the velocity of hydrolysis. Some non-specificity for the terminal amino acid is expressed. The strikingly different rates of hydrolysis of methotrexate and 5-methyltetrahydrofolate have stimulated interest in this enzyme for its potential clinical value in improving the therapeutic index of methotrexate. The folic acid analog methotrexate (4-amino-N10-methylpteroylglutamic acid [MTX]) is a potent antineoplastic agent (1). Its clinical application has been advanced with the use of leucovorn (N6-formyltetrahydrofolic acid) rescue (8, 11, 13, 18, 26), which has been relatively successful in relieving the toxicity of antifolate therapy. The report of a bacterial carboxypeptidase G1 (CPD G1) with hydrolytic activity for MTX introduced the possibility of the enzymatic approach to ameliorating drug toxicity (12, 23). In this report, we describe the partial purification and characterization of another enzyme that catalyzes the hydrolysis of MTX, folic acid (FA), and other derivatives of FA by the reaction shown in Fig. 1. This carboxypeptidase is produced by a bacterium tentatively designated Flavobacterium sp. and differs from CPD G and CPD G1 (15, 19, 23). MATERIALS AND METHODS Chemicals. FA (pteroyl-L-glutamic acid) was purchased from Grand Island Biological Co. dl-N5-methyltetrahydrofolic acid was obtained from Sigma Chemical Co. as the barium salt. It was converted to the sodium salt by the addition of an equal volume of 0.1 M sodium phosphate, pH 6.5, to a 1% solution of the folate in 0.1 M sodium bicarbonate-0.05% potassium ascorbate. Leucovorin (dl-N-5-formyltetrahydrofolic acid, calcium salt) and MTX were provided by Bernard C. Clark of Lederle Laboratories, American Cy-anamid Co., and by Harry B. Wood, Jr., Drug Development Branch, Drug Research and Development, Silver Spring, Md. Chromatographicaily purified MTX (4) was used for kinetic studies. Purified aminopterin was a gift from Francis M. Sirotnak, Sloan-Kettering Institute. Harry B. Wood, Jr., also provided bioautographically pure samples of methasquin (17),

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Medium for Assay of Vitamins with Lactic Acid Bacteria

Cited by 81 publications

References 21 publications

Preparation and Biological Activity of Dihydroaminopterin^*

Preparation and Biological Activity of Dihydroaminopterin^*

Mutagenic Studies of Folic Acid Antagonists

Carboxypeptidase displaying differential velocity in hydrolysis of methotrexate, 5-methyltetrahydrofolic acid, and leucovorin

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Medium for Assay of Vitamins with Lactic Acid Bacteria

Cited by 81 publications

References 21 publications

Preparation and Biological Activity of Dihydroaminopterin*

Preparation and Biological Activity of Dihydroaminopterin*

Mutagenic Studies of Folic Acid Antagonists

Carboxypeptidase displaying differential velocity in hydrolysis of methotrexate, 5-methyltetrahydrofolic acid, and leucovorin

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Preparation and Biological Activity of Dihydroaminopterin^*

Preparation and Biological Activity of Dihydroaminopterin^*