Induced triploidy reduces mercury bioaccumulation in a piscivorous fish

We compared mercury bioaccumulation in triploid and diploid walleye (Stizostedion vitreum) in Narraguinnep Reservoir, Colorado, USA, and made several hypotheses that sex- and ploidy-specific differences in the allocation of energy towards reproductive development would affect mercury bioaccumulation. We tested our hypotheses with linear regression and a bioenergetics model informed by field data. We found diploid walleye had 28-31% higher mercury concentrations on average than triploids, but there were no differences between sexes of the same ploidy. Triploids of mature age exhibited minimal gonadal development when compared to diploids. After accounting for reproductive investment, the bioenergetics model accounted for most of the observed difference in average mercury concentration between ploidies for females. Conversely, the energetic cost of producing testes was low, and gonadal development could not explain observed patterns for males. Costs associated with elevated swimming activity and metabolism by diploid males relative to other groups could explain the difference but requires further investigation. The use of triploid fish in stocking programs could prove useful for reducing mercury in fish destined for human consumption.

Rebutting Pedro J. Silva’s article in Biophysical Chemistry supporting Mitchell-Boyer’s ideas on bioenergetics and advocating murburn concept as a viable explanation for aerobic respiration and oxygenic photosynthesis

Over the last three years, I had pointed out the untenable nature of the proton-centric ‘chemiosmosis driven rotary ATP-synthesis (CRAS)’ explanation for Oxidative Phosphorylation (OxPhos). Recently, Pedro J. Silva (PJS) [Chemiosmotic misunderstandings (2020). Biophys. Chem. 264, 106424] afforded a part of our work his critical attention, but overlooked the large volume of evidence against CRAS and supporting the oxygen-centric murburn mechanism of OxPhos. In his article, PJS also posed some queries on our bioenergetics model. When I offered my rebuttal, the Editor of Biophysical Chemistry refused to publish it. Therefore, I have no other option than to publish the rebuttal as a preprint. Herein, I demonstrate the flaws and lacunae in PJS’s defense of CRAS hypothesis and answer his specific queries and defend the murburn explanation of mOxPhos. The current scientific discourse is crucial for correcting major historical errors in mitochondrial physiology and understanding oxygen’s crucial role in the powering chemistry of life.