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...     

Intramitochondrial localization of δ-aminolaevulate synthetase and ferrochelatase in rat liver

Intramitochondrial loci for delta-aminolaevulate synthetase and ferrochelatase, the initial and final enzymes in haem synthesis, have been found in rat liver. Two different methods of fractionation were applied to mitochondria: (a) sonication and density-gradient centrifugation; (b) treatment with digitonin and differential centrifugation. Similar results were obtained with each technique. delta-Aminolaevulate synthetase is distributed similarly to two known matrix enzymes, malate dehydrogenase and glutamate dehydrogenase. Ferrochelatase is firmly bound to the the inner mitochondrial membrane. These results are considered in terms of the regulation of haem synthesis and in relation to mitochondrial biogenesis.     

The role of obesity in inflammatory bowel disease

In just over a generation overweight and obesity has become a worldwide health concern. The ramifications for this on future health care costs and longevity are consequent, whilst increased adiposity is a harbinger for diabetes, kidney and bone failure, and cancer. An area of intense interest where the role of adiposity is avidly discussed is in inflammatory bowel disease (IBD), which presents mainly as Crohn's disease (CD) and ulcerative colitis (UC). Studies in patients associating IBD with a western diet are divergent. Nevertheless, elegant studies have found gene polymorphisms in humans that in murine models parallel the inflammatory and gut microbiome changes seen in IBD patients. However, an area not to be ignored are the alterations in adipocyte function with ensuing adiposity, in particular and a focus of this review, the dysregulation of the levels of adipocytokines such as leptin and adiponectin. Herein, we present and discuss the known influences of a western diet on IBD in patients and rodent models and how adipocytokines could influence the IBD disease process.     

Innovative microscale workflow from fungi cultures to Cell Wall-Degrading Enzyme screening

This study aimed at developing a complete miniaturized high-throughput screening workflow for the evaluation of the Cell Wall-Degrading Enzyme (CWDE) activities produced by any fungal strain directly cultivated on raw feedstock in a submerged manner. In this study, wheat straw was selected as model substrate as it represents an important carbon source but yet poorly valorised to yield high added value products. Fungi were grown in a microbioreactor in a high-throughput (HT) way to replace the fastidious shaking flask cultivations. Both approaches were compared in order to validate our new methodology. The range of CWDE activities produced from the cultures was assayed using AZO-died and pNP-linked substrates in an SBS plate format using a Biomek FXp pipetting platform. As highlighted in this study, it was shown that the CWDE activities gathered from the microbioreactor cultivations were similar or higher to those obtained from shake flasks cultures, with a lower standard deviation on the measured values, making this new method much faster than the traditional one and suitable for HT CWDE production thanks to its pipetting platform compatibility. Also, the results showed that the enzymatic activities measured were the same when doing the assay manually or using the automated method.     

An energy approach describes spine equilibrium in adolescent idiopathic scoliosis

Biomechanics and Modeling in Mechanobiology - The adolescent idiopathic scoliosis (AIS) is a 3D deformity of the spine whose origin is unknown and clinical evolution unpredictable. In this work, a...     

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...