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Abstract Detail

Physiology & Ecophysiology

Quispe, Naomi [1], Westerhaus, Kathryn [1], Kobayashi, Yasuhiro [1], Maricle, Brian [2].

Effect of sulfide and lactic acid on cytochrome c oxidase activities in plant roots and catfish liver.

Sulfide is well known as a metabolic toxin and lactic acid can affect muscle function, yet specific effects of sulfide and lactic acid on respiration enzymes have not been characterized. The objective of this study was to characterize sulfide and lactic acid toxicity on activities of cytochrome c oxidase (CytOx), an essential enzyme in oxidative phosphorylation. CytOx activity was measured in tissue homogenates from roots of several plant species and catfish liver samples in the presence of increasing concentrations of sulfide (0 to 20 µM) or lactic acid (0 to 100 mM). Increasing sulfide and lactic acid concentration significantly decreased activity in CytOx. Sulfide had a greater effect on the enzyme compared to lactic acid. Activity of CytOx in catfish liver samples was 40-fold higher than in plant roots and was almost 50-fold more sensitive to sulfide. The inhibition constant (Ki) for sulfide was of 0.1 µM in catfish liver and 4.6 µM in plant roots. Lactic acid also reduced CytOx activities. However, the Ki for lactic acid in catfish liver and plant roots was approximately 80 mM and 50 mM, respectively. Our results indicated that sulfide and lactic acid negatively influenced CytOx activities, but to different degrees. CytOx in catfish liver is more susceptible to sulfide toxicity compared to plant roots. Specific mechanisms of inhibition are currently under investigation.

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1 - Fort Hays State University, Department of Biological Sciences, 600 Park St., Hays, Kansas, 67601, United States
2 - Fort Hays State University, Department Of Biological Sciences, 600 Park St., Hays, KS, 67601, United States

reed canarygrass

Presentation Type: Poster
Session: P, Physiology & Ecophysiology
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPE009
Abstract ID:830
Candidate for Awards:None

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