Polarographic Assay of Hydrogen Peroxide Accumulation in Microbial Cultures

The production conditions of superoxide dismutase (SOD) in the cells of Streptococcus lactis by using hyperbaric oxygen (02) are described. The SOD activity of anaerobically grown cells was 5-6 U/mg protein. When the culture broth was pressurized by O2 at 6 atm, the SOD activity was more than twice as high as that under anaerobic culture conditions. However, there is little or no significant increase in SOD activity by exogenous addition of catalase for detoxifying hydrogen peroxide accumulated in the broth andlor controlling the pH of the broth at 6.8 during the pressurization by 02. The increase in SOD activity by hyperbaric O2 was possible not only at the late-logarithmic growth phase but also at the initial time for the stationary growth phase.For improvement of SOD productivity, we tried a two-stage culture in which SOD activity in S. lactis cells was enhanced by pressurizing the culture broth using hyperbaric O2 after achievement of a high-concentration cultivation in the anaerobic fermentation system with a microfiltration module.

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Production of superoxide dismutase in Streptococcus lactis by a combination of use of hyperbaric oxygen and fermentation with cross‐flow filtration

Taniguchi

Hoshino

Itoh

et al. 1992

Biotech & Bioengineering

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The Effect of Light and Zinc on Catalase Activity during the Development of Phycomyces blakesleeanus Bgff.

Hilgenberg

Rausch

Lüken

1981

Biochemie und Physiologie der Pflanzen

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Pro-oxidant/antioxidant balance controls pancreatic β-cell differentiation through the ERK1/2 pathway

et al. 2014

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During embryogenesis, the intrauterine milieu affects cell proliferation, differentiation, and function by modifying gene expression in susceptible cells, such as the pancreatic β-cells. In this limited energy environment, mitochondrial dysfunction can lead to overproduction of reactive oxygen species (ROS) and to a decline in β-cell function. In opposition to this toxicity, ROS are also required for insulin secretion. Here we investigated the role of ROS in β-cell development. Surprisingly, decreasing ROS production in vivo reduced β-cell differentiation. Moreover, in cultures of pancreatic explants, progenitors were highly sensitive to ROS stimulation and responded by generating β-cells. ROS enhanced β-cell differentiation through modulation of ERK1/2 signaling. Gene transfer and pharmacological manipulations, which diminish cellular ROS levels, also interfered with normal β-cell differentiation. This study highlights the role of the redox balance on β-cell development and provides information that will be useful for improving β-cell production from embryonic stem cells, a step in cell therapy for diabetes.

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Polarographic Assay of Hydrogen Peroxide Accumulation in Microbial Cultures

Cited by 9 publications

References 9 publications

Production of superoxide dismutase in Streptococcus lactis by a combination of use of hyperbaric oxygen and fermentation with cross‐flow filtration

Production of superoxide dismutase in Streptococcus lactis by a combination of use of hyperbaric oxygen and fermentation with cross‐flow filtration

The Effect of Light and Zinc on Catalase Activity during the Development of Phycomyces blakesleeanus Bgff.

Pro-oxidant/antioxidant balance controls pancreatic β-cell differentiation through the ERK1/2 pathway

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