D614G Spike Mutation Increases SARS CoV-2 Susceptibility to Neutralization

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High expression of MDM2 protein and low rate of p21(WAF1/CIP1) expression in SCID mice Epstein Barr virus-induced lymphoproliferation.

To study the prevalence of p53 inactivation and MDM2/p21(WAFI/CIP1) expression in severe combined immunodeficient (SCID) mice Epstein-Barr virus (EBV)-induced lymphoproliferation, 19 samples obtained after ip injection of peripheral blood mononuclear cells (PBMCs) from EBV-seropositive donors or lymphoblastoid cell lines (LCL) were analyzed. In all samples tested, overexpression of Ki-67 antigen was shown by immunohistochemistry, indicating a high proliferative index of SCID mice EBV-induced lymphoproliferation. P53 mutations were screened by functional assay in yeast in 14 samples. With this test, a p53-inactivating mutation was found in only one case; the remaining cases exhibited a wild-type p53 pattern. However, an accumulation of p53 protein was detected by immunohistochemistry in six of 19 samples. P21 expression was found in seven of 19 samples but was not correlated with the rate of p53 protein in tumors. In contrast, high levels of nuclear accumulation of MDM2 were found in all samples by immunohistochemistry. These results suggest that a high Ki-67 proliferative index in SCID mice EBV-induced lymphoproliferation is not due to the inactivation of p53 by mutation, but could be associated with an overexpression of MDM2, which would act by a p53-independent mechanism.(J Histochem Cytochem 47:1315-1321, 1999)     

Identification of stsC, the gene encoding the l-glutamine:scyllo-inosose aminotransferase from streptomycin-producing Streptomycetes

Eight new genes, strO-stsABCDEFG, were identified by sequencing DNA in the gene cluster that encodes proteins for streptomycin production of Streptomyces griseus N2-3-11. The StsA (calculated molecular mass 43.5 kDa) and StsC (45.5 kDa) proteins – together with another gene product, StrS (39.8 kDa), encoded in another operon of the same gene cluster – show significant sequence identity and are members of a new class of pyridoxal-phosphate-dependent aminotransferases that have been observed mainly in the biosynthetic pathways for secondary metabolites. The aminotransferase activity was demonstrated for the first time by identification of the overproduced and purified StsC protein as the l-glutamine:scyllo-inosose aminotransferase, which catalyzes the first amino transfer in the biosynthesis of the streptidine subunit of streptomycin. The stsC and stsA genes each hybridized specifically to distinct fragments in the genomic DNA of most actinomycetes tested that produce diaminocyclitolaminoglycosides. In contrast, only stsC, but not stsA, hybridized to the DNA of Streptomyces hygroscopicus ssp. glebosus, which produces the monoaminocyclitol antibiotic bluensomycin; this suggests that both genes are specifically used in the first and second steps of the cyclitol transamination reactions. Sequence comparison studies performed with the deduced polypeptides of the genes adjacent to stsC suggest that the enzymes encoded by some of these genes [strO (putative phosphatase gene), stsB (putative oxidoreductase gene), and stsE (putative phosphotransferase gene)] also could be involved in (di-)aminocyclitol synthesis. Received: 7 January 1997 / Accepted: 24 March 1997     

The Effect of Zinc Sulfate on miR-122, miR-34a,Atioxidants, Biochemical and Histopathological Parameters Following Hepatic Ischemia/Reperfusion Injury in Rats

Biological Trace Element Research - Liver ischemia-reperfusion (IR) injury is a situation which occurs in various conditions such as pringle maneuver and liver transplantation. The regulatory...     

Heterologous expression,purification, and refolding of SRY protein: role of l-arginine as analyzed by simulation and practical study

Molecular Biology Reports - Escherichia coli is a widely-used cell factory for recombinant protein production, nevertheless, high amount of produced protein is seen in aggregated form. The purpose...