Non-enzymic in vitro formation of nitrosamines by bacteria isolated from meat products

Collins‐Thompson, D. L.; Sen, Nrisinha P.; Aris, B.; Schwinghamer, L.

doi:10.1139/m72-306

Cited by 47 publications

(12 citation statements)

References 9 publications

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“…Nitrosation of dimethylamine by rat intestinal flora (14,15) and of dimethylamine and piperidine by Escherichia coli (16) was also found to be partially heat-labile. In some other microbial nitrosation systems, however, boiled cells were as effective as live ones (6,17,18).…”

Section: Experiments 4) No Difference Was Observedmentioning

confidence: 99%

Enhancement of formation of the esophageal carcinogen benzylmethylnitrosamine from its precursors by Candida albicans

Hsia

Sun

Wang

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

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Previous studies in Linxian, an area of China with a high incidence of esophageal carcinoma, showed that fungal infections are common in the esophageal epithelium of patients with either premalignant changes or early esophageal carcinoma. Fungi of the genus Candida were the most frequent invaders. In these areas nitrate and nitrite are often present in high, concentrations in drinking. water and staple grains. The present studies have-established the ability of Candida albicana to augment the nitrosative formation of the esophagus-specific carcinogen, benzylmethylnitrosamine (NBMA; N-nitroso-N-methylbenzylamine).Stationary C. albicans cultures~with pH held at, 6.8 were incubated with the precursors of NBMA, benzylmethylamine (BMA, N-methylbenzylamine) and Na02. There was a significant increase in the amount of NBMA formed in these cultures, compared to precursors-only controls. The amount of NBMA synthesized depended on fungal cell number. Exponentially growing cultures were also able to cause NBMA formation. The identity of the NBMA was confirmed by high-performance liquid chromatographic coelution with authentic NBMA in three solvent systems and by mass spectroscopy. Boiled cells and conditioned medium in which cells had been.incubated were not effective in enhancing nitrosation, Cultured Candida released acidic metab-. olites that reduced the pH of the medium when only a low concentration of buffer was present. Spontaneous nitrosation of BMA was enhanced under these acidic conditions..Thus, C. albicans infecting the esophageal epithelium could cause local formation of NBMA by both cell-mediated catalysis and extracellular decrease in pH.Esophageal carcinoma is the second most common cancer in China, causing 157,000 deaths every year. In Linxian, a county in Northern Honan province, the incidence of esophageal cancer is 178 per 100,000 people per annum, with a death rate of 132 per 100,000 (1). Pathological investigations in Linxian showed that fungal infections were often associated with hyperplasia or dysplasia of the esophageal' epithelium in patients with premalignant changes or early carcinoma (2). More than half of the fungi found in the epithelium were Candida species; Candida albicans was isolated from the hyperplastic epithelium of a patient with esophageal carcinoma in situ: (2). Anti-candida antibody titers were also high in the infected patients (3; unpublished data). An association between fungal infections and esophageal carcinoma was suggested.Are Candida infections of the esophagus causally linked to development of cancer in this tissue? Stimulation of hyperplasia, release of tumor-promoting agents,. and formation of carcinogens. are, possible mechanisms by which fungi could' contribute to the appearance of tumors. Fungi and other microorganisms may enhance formation of nitrosamines from naturally occurring precursors (4-6), and certain nitrosamines are specific inducers of esophageal tumors in rodents (7,8). It is possible that Candida participates in the causation of esophageal cance...

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Section: Experiments 4) No Difference Was Observedmentioning

confidence: 99%

Enhancement of formation of the esophageal carcinogen benzylmethylnitrosamine from its precursors by Candida albicans

Hsia

Sun

Wang

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

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“…Il fatto che la nitrosazione si verifichi a pH prossimi alla neutralità indicherebbe che il processo è di tipo enzimatico, sebbene non siano stati recuperati enzimi liberi (esoenzimi) 80 . 36 , ma non sono state trovato prove che supportassero la natura enzimatica della reazione. 36 , ma non sono state trovato prove che supportassero la natura enzimatica della reazione.…”

Section: Nitrosammineunclassified

Protezione degli alimenti mediante sostanze chimiche e sistemi di biocontrollo

2009

Food

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L'impiego di sostanze chimiche per prevenire o ritardare l'alterazione degli alimenti deriva in parte dal fatto che tali composti sono utilizzati con grande successo nel trattamento di patologie dell'uomo, degli animali e delle piante. Ciò non implica che qualsivoglia composto chemioterapico possa o debba essere impiegato come conservante per alimenti. D'altra parte vi sono alcuni composti chimici utili come conservanti che potrebbero essere inefficaci o addirittura tossici come chemioterapici. A eccezione di alcuni antibiotici, nessuno dei conservanti per alimenti oggi utilizzati trova un impiego reale per la cura dell'uomo e degli animali. Sebbene molteplici sostanze chimiche abbiano un certo potenziale come conservanti alimentari, solo un numero relativamente piccolo è consentito nei prodotti alimentari, ciò è dovuto in gran parte alle stringenti norme di sicurezza stabilite dalla FDA e in misura minore al fatto che non tutti i composti che mostrano attività antimicrobica in vitro esplicano la stessa azione negli alimenti. Di seguito sono descritti i composti maggiormente utilizzati, le loro modalità di azione -se conosciute -e le tipologie di alimenti in cui vengono impiegati.

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“…The fact that nitrosation occurred at near-neutral pH values was taken to indicate that the process was enzymatic, although no cell-free enzyme was obtained (41). Several species of catalasenegative cocci, including E. faecalis, E. faecium, and L. lactis, have been shown to be capable of forming nitrosamines, but the other lactic acid bacteria and pseudomonads tested did not (15). These investigators found no evidence for an enzymatic reaction.…”

Section: Nitrosaminesmentioning

confidence: 99%

Food Preservation with Chemicals

Jay

1998

Modern Food Microbiology

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Non-enzymic in vitro formation of nitrosamines by bacteria isolated from meat products

Cited by 47 publications

References 9 publications

Enhancement of formation of the esophageal carcinogen benzylmethylnitrosamine from its precursors by Candida albicans

Enhancement of formation of the esophageal carcinogen benzylmethylnitrosamine from its precursors by Candida albicans

Protezione degli alimenti mediante sostanze chimiche e sistemi di biocontrollo

Food Preservation with Chemicals

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