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Global warming is one of the most significant and widespread effects of climate change. While early life stages are particularly vulnerable to increasing temperatures, little is known about the molecular processes that underpin their capacity to adapt to temperature change during early development. Using a quantitative proteomics approach, we investigated the effects of thermal stress on octopus embryos. We exposed Octopus berrima embryos to different temperature treatments (control 19°C, current summer temperature 22°C, or future projected summer temperature 25°C) until hatching. By comparing their protein expression levels, we found that future projected temperatures significantly reduced levels of key eye proteins such as S‐crystallin and retinol dehydrogenase 12, suggesting the embryonic octopuses had impaired vision at elevated temperature. We also found that this was coupled with a cellular stress response that included a significant elevation of proteins involved in molecular chaperoning and redox regulation. Energy resources were also redirected away from non‐essential processes such as growth and digestion. These findings, taken together with the high embryonic mortality observed under the highest temperature, identify critical physiological functions of embryonic octopuses that may be impaired under future warming conditions. Our findings demonstrate the severity of the thermal impacts on the early life stages of octopuses as demonstrated by quantitative proteome changes that affect vision, protein chaperoning, redox regulation and energy metabolism as critical physiological functions that underlie the responses to thermal stress. [ABSTRACT FROM AUTHOR]

Exploiting the chemical and growth properties of otoliths, this study demonstrates how environmental archives with high temporal resolution can be developed. Elemental profiles (Ba:Ca and Sr:Ca) of fish otoliths (ear bones) from the estuarine species Acanthopagrus butcheri (black bream) were related to growth increments on a seasonal time scale. A series of mixed effects models were used to investigate biological, temporal, and environmental factors influencing seasonal otolith elemental profiles. Resultant seasonally resolved chemical chronologies were correlated with environmental data (i.e., salinity) to develop an element-salinity regression function, which when fit to an independently derived chemical chronology showed strong agreement between reconstructed and recorded salinities. Support for the element-salinity regression function through independent verification provided confidence in environmental reconstructions derived from an archaeological otolith. This suggests otoliths can be used to reconstruct past environmental conditions over decadal and centennial time scales. Moreover, the application of mixed effect models to develop chemical chronologies also provides information on drivers of elemental profiles and allows a range of ecological questions to be addressed. This approach may be further adapted and employed across a broader range of taxonomic groups and environments. En tirant parti des proprietes chimiques et de la croissance des otolithes, l'etude demontre comment des archives environnementales de haute resolution temporelle peuvent etre etablies. Des profils d'elements (Ba:Ca et Sr:Ca) d'otolithes de poisson de l'espece estuarienne Acanthopagrus butcheri (breme noire) ont ete relies aux increments de croissance a l'echelle saisonniere. Une serie de modeles a effets mixtes a ete utilisee pour examiner les facteurs biologiques, temporels et environnementaux qui influent sur les profils d'elements saisonniers des otolithes. Les chronologies resolues a l'echelle saisonniere en decoulant ont ete correlees a des donnees environnementales (c.-a-d. la salinite) pour definir une fonction de regression element-salinite qui, quand elle est calee sur une chronologie chimique obtenue de maniere independante, montre une bonne concordance entre les salinites reconstituees et enregistrees. La verification independante de la fonction de regression elementsalinite accroit la fiabilite des reconstitutions environnementales tirees d'un otolithe archeologique. Cela donne a penser que les otolithes peuvent etre utilises pour reconstituer des conditions ambiantes passees fi l'echelle de decennies ou de siecles. L'utilisation de modeles a effets mixtes pour etablir des chronologies chimiques fournit en outre de l'information sur les facteurs qui influent sur les profils d'element et permet d'explorer un eventail de questions ecologiques. Cette approche peut etre adaptee et utilisee pour un vaste eventail de groupes taxinomiques et de milieux. [Traduit par la Redaction], Introduction Aquatic ecosystems have been subject to dramatic changes in environmental conditions, such as alterations to natural freshwater flows and shifts in temperature and salinity regimes. Quantifying the direction and [...]

Proteomics, the temporal study of proteins expressed by an organism, is a powerful technique that can reveal how organisms respond to biological perturbations, such as disease and environmental stress. Yet, the use of proteomics for addressing ecological questions has been limited, partly due to inadequate protocols for the sampling and preparation of animal tissues from the field. Although RNAlater is an ideal alternative to freezing for tissue preservation in transcriptomics studies, its suitability for the field could be more broadly examined. Moreover, existing protocols require samples to be preserved immediately to maintain protein integrity, yet the effects of delays in preservation on proteomic analyses have not been thoroughly tested. Hence, we optimised a proteomic workflow for wild-caught samples. First, we conducted a preliminary in-lab test using SDS-PAGE analysis on aquaria-reared Octopus berrima confirming that RNAlater can effectively preserve proteins up to 6 h after incubation, supporting its use in the field. Subsequently, we collected arm tips from wild-caught Octopus berrima and preserved them in homemade RNAlater immediately, 3 h, and 6 h after euthanasia. Processed tissue samples were analysed by liquid chromatography tandem mass spectrometry to ascertain protein differences between time delay in tissue preservation, as well as the influence of sex, tissue type, and tissue homogenisation methods. Over 3500 proteins were identified from all tissues, with bioinformatic analysis revealing protein abundances were largely consistent regardless of sample treatment. However, nearly 10% additional proteins were detected from tissues homogenised with metal beads compared to liquid nitrogen methods, indicating the beads were more efficient at extracting proteins. Our optimised workflow demonstrates that sampling non-model organisms from remote field sites is achievable and can facilitate extensive proteomic coverage without compromising protein integrity. [ABSTRACT FROM AUTHOR]