First person – Shohei Yamamoto

ABSTRACTFirst Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping early-career researchers promote themselves alongside their papers. Shohei Yamamoto is first author on ‘Biophysical and biochemical properties of Deup1 self-assemblies: a potential driver for deuterosome formation during multiciliogenesis’, published in BiO. Shohei conducted the research described in this article while a PhD student and then postdoc in Daiju Kitagawa's lab at Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Tokyo, Japan. He is now a postdoc in the lab of Manuel Théry and Laurent Blanchoin at the Interdisciplinary Research Institute of Grenoble, CEA, Grenoble, France, investigating in vitro reconstitution of cytoskeleton systems.

Findings in redox biology: From H2O2 to oxidative stress

My interest in biological chemistry proceeded from enzymology in vitro to the study of physiological chemistry in vivo. Investigating biological redox reactions, I identified hydrogen peroxide (H2O2) as a normal constituent of aerobic life in eukaryotic cells. This finding led to developments that recognized the essential role of H2O2 in metabolic redox control. Further research included studies on GSH, toxicological aspects (the concept of “redox cycling”), biochemical pharmacology (ebselen), nutritional biochemistry and micronutrients (selenium, carotenoids, flavonoids), and the concept of “oxidative stress.” Today, we recognize that oxidative stress is two-sided. It has its positive side in physiology and health in redox signaling, “oxidative eustress,” whereas at higher intensity, there is damage to biomolecules with potentially deleterious outcome in pathophysiology and disease, “oxidative distress.” Reflecting on these developments, it is gratifying to witness the enormous progress in redox biology brought about by the science community in recent years.

Patterns of aquatic decay and disarticulation in juvenile Indo-Pacific crocodiles (Crocodylus porosus), and implications for the taphonomic interpretation of fossil crocodyliform material

High levels of skeletal articulation and completeness in fossil crocodyliforms are commonly attributed to rapid burial, with decreasing articulation and completeness thought to result from prolonged decay of soft tissue and the loss of skeletal connectivity during ‘bloat and float’. These interpretations are based largely on patterns of decay in modern mammalian and avian dinosaur carcasses. To address this issue, we assessed the decay of buried and unburied juvenile Crocodylus porosuscarcasses in a controlled freshwater setting. The carcasses progressed through typical vertebrate decay stages (fresh, bloated, active decay, and advanced decay), reaching the final skeletal stage on average 56 days after death. Unburied carcasses commenced floating five days post-mortem during the bloated stage, and one buried carcass only commenced floating 12 days post-mortem. While floating, skeletal elements remained articulated within the still coherent dermis, except for thoracic ribs, ischia and pubic bones. The majority of disarticulation occurred at the sediment-–water interface after the carcasses sank during the advanced decay stage, ~ 36 days post-mortem. Based on these results we conclude that fossil crocodyliform specimens displaying high levels of articulation are not the result of prolonged subaerial and subaqueous decay in a low-energy, aqueous environment. Using extant juvenile C. porosus as a proxy for fossil crocodyliforms, rapid burial in an aquatic setting would have to occur prior to the carcass floating, and would also have to continually negate the positive buoyancy associated with bloating. Rapid burial does not have to be the only avenue to preservation of articulation, as other mechanisms such as physical barriers and internal physiological chemistry could prevent carcasses from floating and subsequently disarticulating upon sinking. The inference that a large proportion of skeletal elements could drift from floating carcasses in a low energy setting with minimal scavenging, thereby causing a loss of completeness, seems unlikely.