Haloalkane dehalogenases are enzymes that catalyze the cleavage of the carbon-halogen bond by a hydrolytic mechanism. Genomes of Mycobacterium tuberculosis and M. bovis contain at least two open reading frames coding for the polypeptides showing a high sequence similarity with biochemically characterized haloalkane dehalogenases. We describe here the cloning of the haloalkane dehalogenase genes...

We have previously reported that 7,12-dimethylbenz(a)an thracene (DMBA), given i.v. 24 hr after partial hepatectomy when DNA replication is maximal, binds tightly to DNA, inhibits its synthesis, and induces neoplastic changes in regenerating rat liver. We now report that DMBA injected i.v. 5 hr after partial hepatectomy (i.e., during the early prereplicative phase) inhibits DNA synthesis for at...

Developmental stages of mammary glands influence their susceptibility to initiating events related to carcinogenesis. The "window of susceptibility" to mammary carcinogenesis is classically defined as the time in early puberty when the mammary gland morphology is most sensitive to initiation events. Administration of the polyaromatic hydrocarbon, 7,12-dimethylbenz(a)anthracene (DMBA), in a sing...

This investigation studied the effect of topical application of apigenin on skin tumorigenesis initiated by 7,12-dimethylbenz(a)anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA) in SENCAR mice. Apigenin was a potent inhibitor of epidermal ornithine decarboxylase induction by TPA in a dose-dependent manner from 1 to 20 mumol. Two tumorigenesis studies were conducted. I...

We evaluated the 7, 12dimethylbenz (a) anthracene (DMBA) induced mouse skin tumor development as a function of time and its control by C-Phycocyanin (C-PC, a phycobiliproteins from Spirulina). Oral administration of C-PC inhibited the DMBA induced skin tumor development in term of number and the size of tumors. C-PC administration also prevented the DMBA caused molecular alterations in terms of...

Invariably in every normal rat a single dose of 7, 12-dimethylbenz(a)anthracene, by mouth or injected in a vein, was found to cause apoplexy and massive necrosis in the inner zones of the adrenal cortex; the zona glomerulosa, the adrenal medulla, and a small region of cortex adjacent to the great adrenal vessels were spared from damage. DMBA caused these selective lesions in females and in male...

Twice-weekly i.p. injections of 4 mg phorbol for 10 weeks, after a single feeding of 6mg 7,12-dimethylbenz(a)anthracene (DMBA), in virgin female Wistar rats led to a significant augmentation of mammary tumor induction (78%) as com pared to that resulting from 6 mg DMBA alone (21%). A slight effect, of doubtful significance, was observed when such phorbol treatment was given after feeding 2 mg D...

This investigation studied the effect of topical application of apigenin on skin tumorigenesis initiated by 7,I2-dimethylbenz(a)anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA) in SENCAR mice. Apigenin was a potent inhibitor of epidermal ornithine decarboxylase induction by TPA in a dose-dependent manner from 1 to 20 «imol. Two tumorigenesis studies were conducted. ...

The current study was designed to evaluate the effects of oral administration of the citrus coumarin, isopimpinellin, on skin tumor initiation by topically applied benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA). To evaluate the effects of orally administered isopimpinellin on skin tumor initiation by B[a]P and DMBA, its effects on DNA adduct formation were first evaluated. Fem...

Present study investigated the protective effect of apigenin on cell surface glycoconjugates abnormalities in 7, 12-dimethyldenz(a)anthracene(DMBA) induced hamster buccal pouch carcinogenesis. DMBA painting in the hamster buccal pouch three times per week for 14 weeks developed oral squamous cell carcinoma. The levels of glycoconjugates (Protein bound hexose, Hexosamine, Lipid bound sialic acid...