Fetal glucocorticoid excess programs a range of detrimental outcomes in the adult phenotype, at least some of which may be due to altered adult adrenocortical function. In this study, we determined the effects of maternal dexamethasone treatment on offspring adrenal morphology and function, as well as the interactive effects of postnatal dietary omega-3 (n-3) fatty acids. This postnatal dietary intervention has been shown to alleviate many of the programming outcomes in this model, but whether this is via the effects on adrenal function is unknown. Dexamethasone acetate was administered to pregnant rats (0 . 75 mg/ml drinking water) from day 13 to term. Cross-fostered offspring were raised on either a standard or high-n-3 diet. Adrenal weight (relative to body weight) at 6 months of age was unaffected by prenatal dexamethasone, regardless of postnatal diet, and stereological analysis showed no effect of dexamethasone on the volumes of adrenal components (zona glomerulosa, zona fasciculata/ reticularis or adrenal medulla). Expression of key steroidogenic genes (Cyp11a1 and Star) was unaffected by either prenatal dexamethasone or postnatal diet. In contrast, adrenal expression of Mc2r mRNA, which encodes the ACTH receptor, was higher in offspring of dexamethasone-treated mothers, an effect partially attenuated by the Hn3 diet. Moreover, stress-induced levels of plasma and urinary corticosterone and urinary aldosterone were elevated in offspring of dexamethasone-treated mothers, indicative of enhanced adrenal responsiveness. In conclusion, this study shows that prenatal exposure to dexamethasone does not increase basal adrenocortical activity but does result in a more stress-responsive adrenal phenotype, possibly via increased Mc2r expression.

Summary Climate change and extreme climatic events, such as marine heatwaves (MHWs), are threatening seagrass ecosystems. Metabolomics can be used to gain insight into early stress responses in seagrasses and help to develop targeted management and conservation measures. We used metabolomics to understand the temporal and mechanistic response of leaf metabolism in seagrasses to climate change. Two species, temperate Posidonia australis and tropical Halodule uninervis, were exposed to a combination of future warming, simulated MHW with subsequent recovery period, and light deprivation in a mesocosm experiment. The leaf metabolome of P. australis was altered under MHW exposure at ambient light while H. uninervis was unaffected. Light deprivation impacted both seagrasses, with combined effects of heat and low light causing greater alterations in leaf metabolism. There was no MHW recovery in P. australis. Conversely, the heat‐resistant leaf metabolome of H. uninervis showed recovery of sugars and intermediates of the tricarboxylic acid cycle under combined heat and low light exposure, suggesting adaptive strategies to long‐term light deprivation. Overall, this research highlights how metabolomics can be used to study the metabolic pathways of seagrasses, identifies early indicators of environmental stress and analyses the effects of environmental factors on plant metabolism and health.

Black P erigord truffle (Tuber melanosporum) is one of the most expensive fungi in the world that appreciated by gourmets. Studies have indicated the impact of growing location and soil microorganisms on the aroma profile of truffle. The aroma profile of West Australian black P erigord truffle (Tuber melanosporum) has not been previously reported, which was studied over a 14 day storage period. Sixty-four compounds were identified in all truffle samples. Significant changes (P > 0.05) were observed in 11 key volatiles (carbon dioxide, acetaldehyde, 2-butanone, 3-methyl-1-butanal, toluene, 2-butenal, formic acid 2methyl butyl ester, 3-methyl-1-butanol, 6-methyl-2-heptanol, 3-octanol and dimethyl sulfoxide) over time.Comparison of these results against published aroma profile of European grown black P erigord truffle identified number of significant similarities and differences were also detected. Dimethyl sulfoxide, a compound previously identified in European grown white truffle (Tuber magnatum), was detected. Principle component analysis (PCA) showed that the major changes in the truffle aroma profile took place in the first 7 days of storage.

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