The influence of mercury on the antioxidant enzyme activity of rumen bacteria Streptococcus bovis and Selenomonas ruminantium

Lenártová, V.

doi:10.1016/s0168-6496(98)00077-4

Cited by 15 publications

(17 citation statements)

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“…Thus, the oxidative stress generated by heavy metals has opposing effects in terms of antioxidant response to that of hydrogen peroxide. This was even more evident in the case of SOD, which is known to be induced as the first line of defense against the generation of toxic oxygen species (Lenartova et al 1998). All three strains had similar activities for both catalase and SOD in the presence of Cu.…”

Section: Discussionmentioning

confidence: 97%

“…Cadmium and Hg posses much higher affinity to thiol (-SH) groups of proteins and reductive reserves (e.g., glutathione) in the cell than the latter which has an electrochemical potential well within the physiological range of the cell (Nies 1999). Studies with Hg have demonstrated that it exerts oxidative stress via H 2 O 2 generation, glutathione depletion, and reactivity with membrane bound protein thiols and these may lead to lipid peroxidation (Lenartova et al 1998). To elucidate the role of VHb in making cells highly sensitive to Cd and Hg, but not to Cu, and in contributing to a higher SOD activity but not catalase further more complete studies are necessary and future studies will be aimed at identifying this role of VHb.…”

Section: Discussionmentioning

confidence: 99%

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Vitreoscilla hemoglobin renders Enterobacter aerogenes highly susceptible to heavy metals

et al. 2004

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When expressed in heterologous microorganisms Vitreoscilla hemoglobin (VHb) acts as oxygen storage and causes a higher oxygen uptake. In this study, the effect of this protein on growth, sensitivity and antioxidant properties of Enterobacter aerogenes exposed to metal stress was investigated. The strain expressing VHb was more sensitive to mercury and cadmium as the minimal inhibitory concentration (MIC) for these metals was up to 2-fold lower in this strain than the host and the recombinant strain carrying a comparable plasmid. At lower concentrations than MIC, the metals partially limited growth and caused an inhibition proportional to metal concentration applied. The growth pattern of VHb expressing strain was also distinctly different from other two non-hemoglobin strains. The hemoglobin containing strain showed substantially higher superoxide dismuates (SOD) activity than the non-hemoglobin strains, while catalase levels were similar in all strains. All strains exposed to copper, however, showed similar MIC values, growth patterns, and SOD and catalase levels.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Vitreoscilla hemoglobin renders Enterobacter aerogenes highly susceptible to heavy metals

et al. 2004

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“…Superoxide is eliminated by dismutation to hydrogen peroxide (H 2 O 2 ) by superoxide dismutase (Fridovich 1978) and accumulation of H 2 O 2 is prevented by the action of catalases and peroxidases (Hassan and Fridovich 1978). In our previous experiments we have detected a significant increase in the SOD activity of the ruminal strain Streptococcus bovis 4 ⁄ 1 in the presence of various concentrations of mercury(II) chloride (Lenártová et al 1998). In the present study we have documented the positive effect of nonenzyme antioxidant substances (AOS: seleno-L-methionine, alpha-tocopherol, beta-carotene) on the elimination of environmental stress, evoked by mercury, in the ruminal bacterium Strep.…”

Section: Introductionmentioning

confidence: 89%

“…Ruminants can be exposed to toxic concentrations of different environmental pollutants, including heavy metals, by consumption of contaminated feed and water. The ingested toxic substances can be inhibitory to both the fermentative activity and growth of the microbes, thereby changing the physiological steady state of the rumen fermentation (Javorský et al 1993;Lenártová et al 1998). The pollutants can also contribute to enhancing the free oxyradicals content, which could generate oxidative and environmental stress for ruminal microbes.…”

Section: Introductionmentioning

confidence: 99%

Are ruminal bacteria protected against environmental stress by plant antioxidants?

Holovská

Lenártová

Pristaš

et al. 2002

Lett Appl Microbiol

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Aims: To investigate the activity response of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) of the rumen bacterium Streptococcus bovis following exposure to mercury(II) chloride (HgCl 2 ) in the presence of plant antioxidants. Methods and Results: Streptococcus bovis was grown with 0 or 5 lg ml )1 of HgCl 2 alone or together with antioxidant substances (AOS): seleno-L-methionine (Se), a-tocopherol (atoc), b-carotene (bcar), melatonin (mel). The activities of SOD and GHPx were estimated in supernatants of disrupted bacterial cells. A significant decrease in the Strep. bovis SOD activity in the presence of HgCl 2 and tested AOS, except mel, was observed. The GSHPx activity of Strep. bovis was under the same cultivation conditions nonsignificantly changed and a significant decrease in the GSHPx activity was recorded only in the presence of bcar. Conclusions:The positive effect of Se, atoc and bcar on the elimination of environmental stress, evoked by mercury, in ruminal bacterium Strep. bovis in vitro was documented. Significance and Impact of the Study: The potential role of plant antioxidants in elimination of the environmental stress of ruminal bacteria evoked by heavy metals is discussed.

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“…Several findings on the defense against mercury toxicity in microbes have been already reported. Low concentrations (5 μg/ml) of mercuric ion enhances the activities of antioxidant defense enzymes including SOD, GPx, GR, and mercuric reductase in some rumen bacteria such as Streptococcus bovis and Selenomonas ruminantium, which prevent the toxic effect of mercury on those bacteria (Lenártová et al, 1998). Mitigation of endogenous mercury depends as a part on the presence of antioxidants such as GSH -most abundant intracellular nonprotein thiol that plays a central role in the maintenance of cellular redox status by quenching free radicals generated during oxidative stress (Jan et al, 2011).…”

Section: 미생물학회지 제51권 제4호mentioning

confidence: 99%

Participation of protein disulfide isomerase 2 in the tolerance against mercury toxicity in Schizosaccharomyces pombe

Choi¹,

Lim²,

Kim³

2015

The Korean Journal of Microbiology

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The present work was undertaken to address the role of protein disulfide isomerase 2 (Pdi2) in the mercury-tolerance of Schizosaccharomyces pombe, using the Pdi2-overexpressing recombinant plasmid pYPDI2 and the corresponding vector plasmid pRS316. When exposed to mercuric chloride, the PDI2 overepxression cells grew significantly better than the vector control cells. They revealed the lower levels of intracellular reactive oxygen species (ROS) and nitric oxide (NO), when incubated with mercuric chloride for 6 h, than the vector control cells. The PDI2 overepxression cells contained the higher levels of total glutathione (GSH) and superoxide dismutase (SOD) activity than the vector control cells, after 6 h of incubation in mercuric chloride. However, the PDI2 overepxression cells contained similar levels of glutathione peroxidase (GPx) activities, compared to those of the vector control cells. Taken together, the S. pombe Pdi2 promotes the tolerance against mercury toxicity through up-regulating total GSH and SOD and subsequently attenuating ROS and NO elevations.

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The influence of mercury on the antioxidant enzyme activity of rumen bacteria Streptococcus bovis and Selenomonas ruminantium

Cited by 15 publications

References 0 publications

Vitreoscilla hemoglobin renders Enterobacter aerogenes highly susceptible to heavy metals

Vitreoscilla hemoglobin renders Enterobacter aerogenes highly susceptible to heavy metals

Are ruminal bacteria protected against environmental stress by plant antioxidants?

Participation of protein disulfide isomerase 2 in the tolerance against mercury toxicity in Schizosaccharomyces pombe

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