152 Regulation of the antimicrobial peptide brevinin-1SY in the skin of Rana sylvatica in response to environmental stress

Micromanaging Freeze Tolerance: The Biogenesis and Regulation of microRNAs in Frozen Frogs

“…This is likely because the energy-limited frozen state does not facilitate major reorganizations of the cellular environment. To survive, it appears that the frog has adapted molecular mechanisms that are; [1] modulated by environmental stimuli, [2] applicable to nearly all biological pathways, [3] easily inducible, [4] not energetically costly, and [5] rapidly reversible to allow for smooth transitions between active and dormant states . Indeed, studies on various hypometabolic animals have found this complex hypometabolic state to be orchestrated by a multitude of molecular mechanisms that fit these criteria including;…”

“…This was subsequently modelled using CYTOSCAPE software and clustered using Markov clustering (MCL) default clustering parameters on the STRING combined scores. Two groups were queried separately: [1] the 23 miRNAs downregulated in frozen brains, and [2] the 33 miRNAs downregulated in thawed brains. Pathway enrichment analysis for miRNA-targeted clusters was performed on miRNAs found to significantly changing in response to freezing and thawing.…”

“…Using miRNA-mRNA target predictions at physiologically relevant temperatures, proteinprotein interaction networks, and biological process enrichment, the following targeted gene networks and processes were identified. Clusters predicted that the key pathways targeted by the miRNAs downregulated during the 24 h frozen condition consisted of; [1] intracellular signal transduction pathways, [2] RNA processing and mRNA splicing, [3] synaptic signalling, [4] lipid phosphorylation, [5] microtubule nucleation, [6] DNA replication, [7] generation of precursor metabolites and energy, [8] developmental process, and [9] proton transport and ATP hydrolysis (Fig. 3.3 and Supp.…”

“…Table S3.3). The key networks targeted by the miRNAs downregulated in the 8 h thawing condition were comprised of; [1] intracellular signal transduction, [2] DNA replication, [3] proton transport, [4] RNA processing and mRNA splicing, [5] protein folding and chaperones, [6] synaptic signalling, [7] ATP hydrolysis, [8] microtubule nucleation, [9] generation of precursor metabolites and energy, [10] lipid phosphorylation, [11] oligosach-lipid intermediate biosynthesis, and [12] developmental process ( Fig. 3.4 and Supp.…”

“…When frozen, wood frogs display no detectable brain activity, no breathing, no movement, and a flat-lined heart; and yet, when temperatures warm they are able to thaw, unscathed. Various adaptations are in place to facilitate successful freeze tolerance, these include; [1] minimization of cell volume reduction and excessive extracellular ice formation via the synthesis and distribution of cryoprotectant glucose , [2] global metabolic rate depression and reprioritization of energy usage, and [3] upregulation and activation of select pro-survival and protective mechanisms . Indeed, despite being in a hypometabolic state, wood frogs must expend energy on protective functions, such as antioxidant defenses (Dawson and Storey, 2016), to ensure that they can endure the myriad of freeze-associated challenges that include; dehydration, mechanical damage from ice, anoxia/ischemia, hyperglycemia, etc.…”