A residue-level investigation of the equilibrium unfolding of the C2A domain of synaptotagmin 1

Fibroblast growth factor (FGF) 1 is known to be released in response to cellular stress conditions through formation of a multi-protein complex with synaptotagmin 1 and S100A13. In this study, we characterized the denaturant-induced unfolding of synaptotagmin 1, C2A domain in a residue-specific manner by NMR spectroscopy. The amide protons of 30 residues distributed throughout the 3D structure of the whole protein could be followed in a series of ¹H-¹⁵N HSQC spectra recorded from 0 to 8 M urea under equilibrium conditions. The midpoint for the urea-induced unfolding obtained from NMR coincides with those obtained from steady state fluorescence and CD spectroscopy, revealing that the protein unfolds via a two-state mechanism without accumulating stable intermediates. The thermodynamic parameter obtained from the denaturation curve illustrates the cooperative unfolding of the C2A domain. The implications of C2A domain folding in relation to the release of FGF-1 from the multi-protein complex were discussed.     

Acute and subacute toxicity studies of Aegle marmelos Corr., an Indian medicinal plant.

This study was designed to elucidate the toxicity of the widely used plant Aegle marmelos in rats. We have taken total alcoholic, total aqueous, whole aqueous and methanolic extracts isolated from the leaves of A. marmelos and studied their toxic effects. Acute, subacute and LD(50) values were determined in experimental rats. The dead animals were obtained from primary screening studies, LD(50) value determination experiments and acute studies subjected to postmortem studies. The external appearance of the dead animals, the appearance of the viscera, heart, lungs, stomach, intestine, liver, kidney, spleen and brain were carefully noted and any apparent and significant features or differences from the norm were recorded. Following the chronic administration of A. marmelos for 14 days, the vital organs such as heart, liver, kidney, testis, spleen and brain were carefully evaluated by histopathological studies and any apparent and significant changes or differences from the norm were studied. From the acute administration of A. marmelos, the LD(50) values were determined using graphical method. The hearts stopped in systolic stand-still in the acute experiments. There were no remarkable changes noticed in the histopathological studies after 50 mg/kg body wt of the extracts of A. marmelos when administered intraperitoneally for 14 days successively. Pathologically, neither gross abnormalities nor histopathological changes were observed. After calculation of LD(50) values using graphical methods, we found a broad therapeutic window and a high therapeutic index value for A. marmelos extracts. Intraperitoneal administration of the extracts of the leaves of A. marmelos at doses of 50, 70, 90 and 100 mg/kg body wt for 14 consecutive days to male and female Wistar rats did not induce any short-term toxicity. Collectively, these data demonstrate that the extracts of the leaves of A. marmelos have a high margin of drug safety.     

Diverse Brain Myeloid Expression Profiles Reveal Distinct Microglial Activation States and Aspects of Alzheimer’s Disease Not Evident in Mouse Models

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Plasmid-mediated degradation of o- and p-phthalate by Pseudomonas fluorescens

A Pseudomonas fluorescens strain SKP3 capable of utilizing both phthalic acid and terephthalic acid as sole source of carbon and energy was isolated by enrichment technique. Phthalic acid, terephthalic acid and protocatechuic acid were easily oxidized by both phthalate-grown and glucose-grown cells without a lag period. Phthalic acid is metabolized through the ortho cleavage pathway and terephthalic acid through the meta cleavage pathway and the enzymes of the two pathways are constitutive in nature. A large plasmid of approximately 140kb in size was found to be involved in the degradation of phthalates. The catabolic plasmid pSKL was transferable to different hosts.     

A System for Distinguishing Octoploid Strawberry Cultivars Using High-Throughput SNP Genotyping

Cultivated strawberry (Fragaria × ananassa) is an important commercial berry crop grown throughout the world. Improved strawberry cultivars are developed to meet the needs of consumers and breeders. Strawberries are usually propagated through runners, which sometimes lead to mislabeling or misinterpretation of cultivars. However, perfect identification of strawberry cultivars is essential for germplasm maintenance and for breeding programs. Molecular marker technology has been widely used to distinguish cultivars of other crops, but marker development in octoploid strawberries is complicated. Therefore, SNP marker with high-density and even distribution in the genome has been used currently as efficient DNA markers. In this report, previously published high-quality poly high resolution (PHR) SNPs from the 90 K Axiom® SNP array were utilized to develop a Fluidigm 24 SNPs genotyping system. Hundred nine (109) octoploid strawberry cultivars were screened using this 24 SNPs chip set. In addition, 24 SNPs were mapped to six chromosomes of diploid strawberry (Fragaria vesca). Our developed SNPs fluidigm genotyping is automatable, easy and reliable for processing and interpretation of data. Thus, this high-throughput SNP genotyping system will be a useful tool for distinguishing strawberry cultivars and find out parent-offspring relationship.