Short-term calorie restriction enhances adult hippocampal neurogenesis and remote fear memory in a Ghsr-dependent manner.

The beneficial effects of calorie restriction (CR) have been described at both organismal and cellular levels in multiple organs. However, our understanding of the causal mediators of such hormesis is poorly understood, particularly in the context of higher brain function. Here, we show that the receptor for the orexigenic hormone acyl-ghrelin, the growth hormone secretagogue receptor (Ghsr), is enriched in the neurogenic niche of the hippocampal dentate gyrus (DG). Acute elevation of acyl-ghrelin levels by injection or by overnight CR, increased DG levels of the neurogenic transcription factor, Egr-1. Two weeks of CR increased the subsequent number of mature newborn neurons in the DG of adult wild-type but not Ghsr(-/-) mice. CR wild-type mice also showed improved remote contextual fear memory. Our findings suggest that Ghsr mediates the beneficial effects of CR on enhancing adult hippocampal neurogenesis and memory.

Drug susceptibility in Mycobacterium tuberculosis of a sample of patients in Guinea Bissau.

Sputum samples from patients with known or suspected tuberculosis were collected in Bissau, Guinea Bissau, and isolates belonging to the Mycobacterium tuberculosis complex (M. tuberculosis, M. bovis or M. africanum) were examined for their susceptibility to the 4 drugs streptomycin, isoniazid, ethambutol and rifampicin. Of 59 M. tuberculosis complex isolates only 2 were resistant to any of the drugs (isoniazid). Thus there is little resistance to these first line drugs among M. tuberculosis isolates from patients in Guinea Bissau.