Molecular basis for the diversification of lincosamide biosynthesis by pyridoxal phosphate-dependent enzymes.

The biosynthesis of the lincosamide antibiotics lincomycin A and celesticetin involves the pyridoxal-5'-phosphate (PLP)-dependent enzymes LmbF and CcbF, which are responsible for bifurcation of the biosynthetic pathways. Despite recognizing the same S-glycosyl-L-cysteine structure of the substrates, LmbF catalyses thiol formation through β-elimination, whereas CcbF produces S-acetaldehyde through decarboxylation-coupled oxidative deamination. The structural basis for the diversification mechanism remains largely unexplored.

Crystal structure of a novel heterooligomeric aminotransferase from Serratia sp. ATCC 39006 provides insights into function.

Serratia sp. ATCC 39006 has two tandemly positioned genes, ser4 and ser5, both annotated as sugar aminotransferases, in a putative secondary metabolite biosynthetic gene cluster. Ser5 possesses a complete fold-type I aminotransferase fold, while Ser4 lacks the N- and C-terminal regions and a catalytically important lysine residue of fold-type I aminotransferase.

Frontal neurodegeneration associated with Frontal Assessment Battery in early Alzheimer's disease.

Background: The Frontal Assessment Battery (FAB) is widely used to assess executive dysfunction in patients with amnestic mild cognitive impairments due to Alzheimer's disease (aMCI-AD), but its neurobiological meaning is unclear. To elucidate this, we examined the relationship between the FAB score and three key imaging biomarkers: gray matter volume, amyloid-beta (Aβ) deposition, and glucose metabolism.

Methods: Twenty Aβ- and tau-positive aMCI-AD patients and age-matched controls underwent structural magnetic resonance imaging and positron emission tomography with [C]PiB and [F]FDG.

Efficacy of a melatonin receptor agonist and orexin receptor antagonists in preventing delirium symptoms in the olderly patients with stroke: a retrospective study.

Background: Post-stroke delirium affects between 24% and 43% of patients, and negatively impacts patient outcomes. Recently, research attention has been on preventive interventions for delirium, with melatonin receptor agonists and orexin receptor antagonists reported to be effective in preventing delirium in intensive care unit patients. However, the efficacy of these agents in preventing post-stroke delirium remain unclear.