Biology subjects

Gardner, J. D.

Publications and source records attributed to Gardner, J. D..

3 recordsLinked to original sources

bioRxiv2021

H2S Prodrug, SG-1002, Protects Against Myocardial Oxidative Damage and Hypertrophy via Induction of Cystathionine beta-Synthase and Antioxidant Proteins

Endogenously produced hydrogen sulfide (H2S) is critical for cardiovascular homeostasis. Therapeutic strategies aimed at increasing H2S levels have proven cardioprotective in models of acute myocardial infarction (MI) and heart failure (HF). The present study was undertaken to investigate the effects of a novel H2S prodrug, SG-1002, on stress induced hypertrophic signaling in murine HL-1 cardiac muscle cells. Treatment of HL-1 cells with SG-1002 under serum starvation without or with H2O2 increased the levels of H2S, H2S producing enzyme, cystathionine {beta}-synthase (CBS) as well as antioxidant protein levels, such as super oxide dismutase1 (SOD1) and catalase and decreased oxidative stress. SG-1002 also decreased the expression of hypertrophic/HF protein markers such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in stressed HL-1 cells. Treatment with SG-1002 caused a significant induction of cell viability and a marked reduction of cellular cytotoxicity in HL-1 cells under serum starvation incubated or with H2O2. Experimental results of this study suggest that SG-1002 attenuates myocardial cellular oxidative damage and/or hypertrophic signaling via increasing H2S levels or H2S producing enzyme, CBS and antioxidant proteins.

cell biology↗

bioRxiv2019

Early Tetrapodomorph Biogeography: Controlling for Fossil Record Bias in Macroevolutionary Analyses

ABSTRACTThe fossil record provides direct empirical data for understanding macroevolutionary patterns and processes. Inherent biases in the fossil record are well known to confound analyses of this data. Sampling bias proxies have been used as covariates in regression models to test for such biases. Proxies, such as formation count, are associated with paleobiodiversity, but are insufficient for explaining species dispersal owing to a lack of geographic context. Here, we develop a sampling bias proxy that incorporates geographic information and test it with a case study on early tetrapodomorph biogeography. We use recently-developed Bayesian phylogeographic models and a new supertree of early tetrapodomorphs to estimate dispersal rates and ancestral habitat locations. We find strong evidence that geographic sampling bias explains supposed radiations in dispersal rate (potential adaptive radiations). Our study highlights the necessity of accounting for geographic sampling bias in macroevolutionary and phylogenetic analyses and provides an approach to test for its effect.View Full Text

paleontology↗

bioRxiv2019

The Relationship Between Genome Size and Metabolic Rate in Extant Vertebrates

Genome size has long been hypothesized to affect metabolic rate in various groups of animals. The mechanism behind this proposed association is the nucleotypic effect, in which large nucleus and cell sizes influence cellular metabolism through surface area-to-volume ratios. Here, we provide a review of the recent literature on the relationship between genome size and metabolic rate. We also conduct an analysis using phylogenetic comparative methods and a large sample of extant vertebrates. We find no evidence that the effect of genome size improves upon models in explaining metabolic rate variation. Not surprisingly, our results show a strong positive relationship between metabolic rate and body mass, as well as a substantial difference in metabolic rate between endothermic and ectothermic vertebrates, controlling for body mass. The presence of endothermy can also explain elevated rate shifts in metabolic rate whereas genome size cannot. We further find no evidence for a punctuated model of evolution for metabolic rate. Our results do not rule out the possibility that genome size affects cellular physiology in some tissues, but they are consistent with previous research suggesting little support for a direct functional connection between genome size and basal metabolic rate in extant vertebrates.

evolutionary biology↗