Glutamate oxidation in mitochondria from the gills of oysters (Crassostrea virginica Gmelin) acclimated to sea water (SW) is sensitive to assay medium osmolanty. Compared to a medium of the osmolarity of sea water, decreasing osmolarity stimulates glutamate oxidation and increasing osmolarity inhibits glutamate oxidation. Glutamate oxidation by mitochondria from oysters acclimated to dilute sea water (DSW) is 2.5-fold greater than in SW animals when each is assayed under isosmotic conditions. The maximal rates obtained in both acclimation groups are equal. Although the DSW animals were acclimated to an osmolarity approximately 660 mosmol 1−1 lower than SW animals, the osmotic optimum was only 100–200 mosmol 1−1 lower in the former group. Isolation medium osmolarity does not affect the osmolarity at which the maximum rate of glutamate oxidation is observed in either acclimation group. A low-osmolarity isolation medium reduces the oxidation rates and quality of the mitochondria, as assessed by the respiratory control ratio in both acclimation groups. These data suggest that an optimal matrix solute concentration or ionic strength is required for maximal rates of glutamate oxidation rather than an optimal mitochondrial volume. The optimal mitochondrial matrix milieu can be achieved both by acclimation to dilute sea water and by incubation in hypo-osmotic media.
In the field: an interview with Martha Muñoz
Martha Muñoz is an Assistant Professor at Yale University, investigating the evolutionary biology of anole lizards and lungless salamanders. In our new Conversation, she talks about her fieldwork in Indonesia, Costa Rica, the Dominican Republic and the Appalachian Mountains, including a death-defying dash to the top of a mountain through an approaching hurricane.
Graham Scott in conversation with Big Biology
Graham Scott talks to Big Biology about the oxygen cascade in mice living on mountaintops, extreme environments for such small organisms. In this JEB-sponsored episode, they discuss the concept of symmorphosis and the evolution of the oxygen cascade.
Propose a new Workshop
-GSWorkshop.png?versionId=3846)
Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Manipulation of mitochondrial function affects red carotenoid metabolism in a marine copepod
Tigriopus californicus copepods with the most powerful mitochondria are the brightest red, providing an honest and direct link between the attractiveness of a creature and their metabolic prowess.
The physiological cost of colour change
In their Review, Ateah Alfakih, Penelope Watt and Nicola Nadeau discuss the energetic cost of colour change and highlight how this can be avoided or lessened in animals that change colour rapidly or slowly.
Social media
