Cerebral preconditioning constitutes the brain's adaptation to lethal ischemia when first exposed to mild doses of a subtoxic stressor. The phenomenon of preconditioning has been largely studied in the heart, and data from in vivo and in vitro models from past 2-3 decades have provided sufficient evidence that similar machinery exists in the brain as well. Since preconditioning results in a transient protective phenotype labeled as ischemic tolerance, it can open many doors in the medical warfare against stroke, a debilitating cerebrovascular disorder that kills or cripples thousands of people worldwide every year. Preconditioning can be induced by a variety of stimuli from hypoxia to pharmacological anesthetics, and each, in turn, induces tolerance by activating a multitude of proteins, enzymes, receptors, transcription factors, and other biomolecules eventually leading to genomic reprogramming. The intracellular signaling pathways and molecular cascades behind preconditioning are extensively being investigated, and several first-rate papers have come out in the last few years centered on the topic of cerebral ischemic tolerance. However, translating the experimental knowledge into the clinical scaffold still evades practicality and faces several challenges. Of the various preconditioning strategies, remote ischemic preconditioning and pharmacological preconditioning appears to be more clinically relevant for the management of ischemic stroke. In this review, we discuss current developments in the field of cerebral preconditioning and then examine the potential of various preconditioning agents to confer neuroprotection in the brain.

The oomycetous phytopathogen Pythium myriotylum secretes cellulases for growth/nutrition of the necrotroph. Cellulases are multi-enzyme system classified into different glycoside hydrolase (GH) families. The present study deals with identification and characterization of GH gene sequence from P. myriotylum by a PCR strategy using consensus primers. Cloning of the full-length gene sequence using genome walker strategy resulted in identification of 1230-bp P. myriotylum GH gene sequence, designated as PmGH1. Analysis revealed that PmGH1 encodes a predicted cytoplasmic 421 amino acid protein with an apparent molecular weight of 46.77 kDa and a theoretical pI of 8.11. Tertiary structure of the deduced amino acid sequence showed typical (α/β)8 barrel folding of family 1 GHs. Sequence characterization of PmGH1 identified the conserved active site residues, viz., Glu 181 and Glu 399, that function as acid-base catalyst and catalytically active nucleophile, respectively. Binding sites for N-acetyl-D-glucosamine (NAG) were revealed in the PmGH1 3D structure with Glu181 and Glu399 positioned on either side to form a catalytic pair. Phylogenetic analysis indicated a closer affiliation of PmGH1 with sequences of GH1 family. Results presented are first attempts providing novel insights into the evolutionary and functional perspectives of the identified P. myriotylum GH.