One of the tissues of the central nervous system most affected by diabetes is the retina. Despite a growing understanding of the biochemical processes involved in glucose toxicity, little is known about the physiological consequences of chronic high

The retina consumes massive amounts of energy, yet its metabolism remains poorly understood. Here, we manipulated retinal energy metabolism under entirely controlled conditions and utilised 1H-NMR metabolomics, in situ enzyme detection, and cell viability readouts to uncover the pathways of retinal energy production. Our experiments resulted in varying degrees of photoreceptor degeneration, while the inner retina and retinal pigment epithelium were essentially unaffected. Notably, rod photoreceptors relied strongly on oxidative phosphorylation, but only mildly on glycolysis. Conversely, cone photoreceptors were highly dependent on glycolysis but insensitive to electron transport chain decoupling. Moreover, photoreceptors uncouple glycolytic and Krebs-cycle metabolism via three different pathways: 1) the mini-Krebs cycle, fuelled by glutamine and branched chain amino acids, generating N-acetylaspartate; 2) the alanine-generating Cahill cycle; 3) the lactate-releasing Cori cycle. These findings forward the understanding of retinal physiology and pathology, and shed new light on neuronal energy homeostasis and the pathogenesis of neurodegenerative diseases.

Spiders of the family Sicariidae pose a serious threat to affected populations, and Loxosceles laeta (Nicolet) is considered the most venomous species. Development of nontoxic olfaction-based spider repellents or traps is hindered by a current lack of knowledge regarding olfactory system function in arachnids. In the present study, general plant odorants and conspecific odors were tested for behavioral responses in L. laeta. Although general odorants triggered neither attraction nor aversion, conspecific odor of the opposite sex caused aversion in females, and attraction in males. These results support the presence of a specific olfactory system for the detection of conspecifics in L. laeta, but suggest the absence of a broadly tuned system for general odorant detection in this species.