Anu Augustine

Using a positional candidate-gene approach, we show that semi-sterile desynaptic8 mutants are associated with deleterious variants of the barley homolog of XRCC2 (X-Ray Repair Cross Complementing 2). In barley XRCC2 mutants, the initial meiotic progression is normal, albeit with a small delay in initiation, with completion of synapsis. However, the absence of HvXRCC2 subsequently leads to a dramatic reduction in the number of crossovers, chromosome mis-segregation, and infertility, suggesting that HvXRCC2 plays a major role in recombination. This mutant phenotype is congruent with that reported in mammalian studies but contrasts with the XRCC2 mutant in Arabidopsis which is fertile, exhibits normal chromosome pairing and correct chromosome segregation, and is associated with an increased rate of crossovers. This observation indicates that the XRCC2 mutant phenotype in Arabidopsis is not representative of all plants and that XRCC2 is not a good candidate for the modulation of recombination in barley.

Using a positional candidate-gene approach we show that semi-sterile desynaptic8 mutants are associated with deletions in or complete knockout of the barley homolog of XRCC2 ( X-Ray Repair Cross Complementing 2 ). In barley XRCC2 mutants, the initial meiotic progression is normal, albeit with a small delay in initiation, with completion of synapsis. However, the absence of HvXRCC2 subsequently leads to a dramatic reduction in the number of crossovers, chromosome mis-segregation, and infertility, suggesting that HvXRCC2 plays a major role in recombination. This mutant phenotype is congruent with that reported in mammalian studies but contrasts with the XRCC2 mutant in Arabidopsis which is fertile, exhibits normal chromosome pairing and correct chromosome segregation, and is associated with an increased rate of crossovers. This indicates that the XRCC2 mutant phenotype in Arabidopsis is not representative of all plants and that XRCC2 is not a good candidate for the modulation of recombination in barley. Highlight: The mutants of the barley homolog of XRCC2 exhibit delays in replication leading to defective meiosis, altered RAD51 orthologue behaviour, and significant reduction in the number of crossovers as in canonical mammalian XRCC2 mutants but unlike those in Arabidopsis.

Alzheimer’s disease (AD), also called senile dementia is a neurodegenerative disease seen commonly in the elderly and is characterised by the formation of β-amyloid plaques and neurofibrillary tangles (NFT). Though a complete understanding of the disease is lacking, recent studies showed the role of the enzyme acetylcholinesterase (AChE) in pathogenesis. Finding new lead compounds from natural sources has always been a quest for researchers. Endophytic fungi are a set of microbes that reside within plants without causing any harm. This study focuses on screening endophytes for the production of active acetylcholinesterase inhibitors. Five endophytic fungi were isolated from Catharanthus roseus and screened for AChE inhibitory activity. Three isolates were found to inhibit AChE inhibitory activity and were distinguished based on molecular and microscopic methods. The mycelial extract was taken for the bioassay-guided column chromatography and TLC was performed on the active fraction. The GC–MS and NMR analysis identified the active compounds in the extract as 9-hexadecen-1-ol and erucamide. Molecular docking studies revealed that the compounds are thermodynamically feasible and have significant glide scores. Computational studies revealed that the hydroxyl group of 9-hexadecen-1-ol forms a hydrogen bond with Ser 293 in the active site of AChE, whereas the active site interactions were predominantly hydrophobic in the case of erucamide and are reflected in AChE inhibition assays.

Mangroves are salt tolerant plants inhabiting saline environment. Multiple factors contribute to their salt tolerance and we need multifaceted approach to reveal the mechanisms of salt tolerance in the plant. In the present study, leaves of the mangrove, Rhizophora mucronata grown in the presence and absence of salt were used, free amino acids and the expression of selected genes were analyzed. Chromatographic technique showed the accumulation of free amino acids like proline, glycine, aspartic acid, valine, leucine and glutamic acid in the presence of salt. RNA was isolated from the leaf sample and cDNA was synthesized. Gene specific primers were designed and standardized. Among the genes studied (P5CS, BADH, NHX1), Betaine Aldehyde dehydrogenase (BADH) gene was found to be expressed.