Effect of bacterial cultures on microbial toxicity assessment

Liu, D.

doi:10.1007/bf01609743

Cited by 11 publications

(6 citation statements)

References 22 publications

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“…Dehydrogenase (DHA) and esterase activity (EA) tests were carried out as described by Liu[11] and Obst and Holzapfel-Pschorn,[12] respectively. Bacterial cell membrane was prepared as described by Kumar and Upreti.…”

Section: Methodsmentioning

confidence: 99%

Reduction of chromium-vi by chromium resistant lactobacilli: A prospective bacterium for bioremediation

Mishra¹,

Sinha²,

Kannan³

et al. 2012

Toxicol Int

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Chromium is a toxic heavy metal, which primarily exists in two inorganic forms, Cr (VI) and Cr (III). Highly soluble hexavalent chromium is carcinogenic due to its oxidizing nature. It is well established that the intestinal bacteria including Lactobacilli have regulatory effect on intestinal homeostasis and a breakdown in the relationship between intestinal cells and bacteria results in the manifestation of gastrointestinal (GI) disorders. In this study Cr (VI) resistance was developed in Lactobacillus strains and the reduction of Cr (VI) was evaluated. All resistant strains showed similarities with their respective normal strains and did not acquire resistance to various antibiotics. A complete bacterial reduction of 32ppm Cr (VI) was observed within 6 to 8 hours. The presence of chromate reducing enzyme have also been established following the partial purification (2 to 5 fold) and characterization of chromate reductase in Lactobacillus strains. The chromate reductase of our strains showed optimum activity at pH 6.0 and 30°C. To our knowledge; these strains are fast in Cr (VI) reduction than any other known bacteria. The results suggest that chromate- resistant Lactobacillus strains would be useful for chromium detoxification from GI-tract as well as for bioremediation of hexavalent chromium from contaminated environment.

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Section: Methodsmentioning

confidence: 99%

Reduction of chromium-vi by chromium resistant lactobacilli: A prospective bacterium for bioremediation

Mishra¹,

Sinha²,

Kannan³

et al. 2012

Toxicol Int

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“…Dehydrogenase and esterase activity (EA) tests were carried out as described by Liu (1985) and Obst & Holzapfel‐Pschorn (1988), respectively. Alkaline phosphatase (EC 3.1.3.1) was determined according to Weiser (1973) and Ca 2+ ‐Mg 2+ ‐ATPase (EC 3.6.1.3) as described by Hidalgo et al (1983).…”

Section: Methodsmentioning

confidence: 99%

Alterations in rat gut bacteria and intestinal epithelial cells following experimental exposure of antimicrobials

Upreti

Kannan

Pant

2008

FEMS Immunology &Amp; Medical Microbiology

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The intestinal bacteria are known to play a significant role in intestinal homoeostasis and the mucosal immune system. In vitro interactions of Ampicillin (0.5-2.0 mg mL À1 ), Amphotericin-B (25-200 mg mL À1 ) and Ciprofloxacin (50-500 ng mL À1 ) with Escherichia coli, Pseudomonas sp. (Gram-negative), Lactobacillus sp., Staphylococcus sp. (Gram-positive), total mixed population of gut bacteria and intestinal epithelial cells were studied. In vitro exposure of Ciprofloxacin showed significant dose-dependent inhibition throughout the growth phase in bacteria. Similar patterns of concentration-dependent changes in membrane transport enzymes and structural constituents, dehydrogenase activity associated with respiratory and energy-producing processes and esterase activity test linked to the general heterotrophic activity of the cell were observed in both bacteria and epithelial cells. The antibiotic effects were in the order of Amphotericin-B o Ampicillin o Ciprofloxacin. Validation studies were conducted using rat intestinal loops filled with different concentrations of antibiotics and incubated for 30 min. In situ changes in epithelial cell membrane enzymes and constituents also indicated similar trends as observed following in vitro exposures. The findings suggest that these antibiotics exert similar cytotoxic effects on intestinal epithelial cells and gut bacteria. Thus, gut bacteria can be used for in vitro screening of gastrointestinal-cellular toxicity caused by antibiotics.

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“…3. The dose concentration-response curves typify microbial response to toxic chemicals, in that the enzyme activity is stimulated at low toxicant concentrations, the hormesis effect (dtebbing, 1982), and inhibited at higher concentration levels (Liu, 1985). For ease of comprehension, Table I presents summary results of the acute toxicity effects (IC,,) of 2,4-DNT and its three metabolites to the six bacterial cultures.…”

Section: Resultsmentioning

confidence: 99%

“…The toxicity of 2,4-DNT and its biotransformation products to microorganisms was determined using the resazurin reduction procedure (Liu and Thomson, 1983) and the natural bacterial isolates as the test organisms (Liu, 1985). The test chemicals were first dissolved in DMSO to form stock solutions and their toxicities were assessed at several concentration levels.…”

Section: Toxicity Assaymentioning

confidence: 99%

Rationale for including metabolites in chemical toxicity bioassay

Liu¹,

Maguire²,

Dutka³

et al. 1990

Environ. Toxicol. Water Qual.

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Toxicity and biodegradability are major factors affecting the fate and behavior of an organic contaminant in the environment. In this report, 2,4-dinitrotoluene (DNT), an important industrial chemical, was used as a model toxicant to demonstrate that toxicity and biodegradability are intimately related in determining a chemical's effect and impact on the total ecosystem. DNT was found to be aerobically stable, but could undergo anaerobic biotransformation with the formation of three metabolites. One of the metabolites, namely 2-nitroso-4-nitrotoluene, was extremely toxic to the six test bacterial isolates, while the other two aminonitro metabolites and the parent compound DNT were much less toxic or nontoxic to the bacterial cultures. It is suggested that the incorporation of some known metabolites into short-term bioassay procedures could increase the reliability of these tests in the impact assessment of toxic chemicals on the environment. In addition, the difference between toxicity data generated from short-term bioassay procedures and those from long-term toxicological studies was also delineated from a biochemical viewpoint.

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Effect of bacterial cultures on microbial toxicity assessment

Cited by 11 publications

References 22 publications

Reduction of chromium-vi by chromium resistant lactobacilli: A prospective bacterium for bioremediation

Reduction of chromium-vi by chromium resistant lactobacilli: A prospective bacterium for bioremediation

Alterations in rat gut bacteria and intestinal epithelial cells following experimental exposure of antimicrobials

Rationale for including metabolites in chemical toxicity bioassay

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