Lymphoproliferation disorder in mice explained by defects in Fas antigen that mediates apoptosis.

Fas antigen is a cell-surface protein that mediates apoptosis. It is expressed in various tissues including the thymus and has structural homology with a number of cell-surface receptors, including tumour necrosis factor receptor and nerve growth factor receptor. Mice carrying the lymphoproliferation (lpr) mutation have defects in the Fas antigen gene. The lpr mice develop lymphadenopathy and suffer from a systemic lupus erythematosus-like autoimmune disease, indicating an important role for Fas antigen in the negative selection of autoreactive T cells in the thymus.     

Catalase activity in electrically stimulated muscle

Summary 10 min of electrical stimulation resulted in a significant rise in gastrocnemius catalase activity.     

Y chromosome sequence variation and the history of human populations

Binary polymorphisms associated with the non-recombining region of the human Y chromosome (NRY) preserve the paternal genetic legacy of our species that has persisted to the present, permitting inference of human evolution, population affinity and demographic history. We used denaturing high-performance liquid chromatography (DHPLC; ref. 2) to identify 160 of the 166 bi-allelic and 1 tri-allelic site that formed a parsimonious genealogy of 116 haplotypes, several of which display distinct population affinities based on the analysis of 1062 globally representative individuals. A minority of contemporary East Africans and Khoisan represent the descendants of the most ancestral patrilineages of anatomically modern humans that left Africa between 35,000 and 89,000 years ago.     

Mouse p53 inhibits SV40 origin-dependent DNA replication

p53 is a cellular phosphoprotein that is present at elevated concentrations in cells transformed by different agents. p53 complementary DNA expression-constructs immortalize primary cells in vitro and co-operate with an activated ras oncogene in malignant transformation. Several reports have implicated p53 in mammalian cell cycle control and specifically with events occurring at the G0-G1 boundary. p53 forms specific complexes with simian virus 40 (SV40) large-T antigen, and such complexes are found associated with both replicating and mature SV40 DNA in lytically infected cells. In an accompanying paper Gannon and Lane report that in in vitro plate-binding assays, mouse p53 can displace polymerase alpha from complex with T-antigen. We have examined the in vivo consequences of expressing wild-type and mutant p53 proteins from other species in SV40-transformed monkey cells. We report here that expression of mouse p53 results in a substantial and selective inhibition of SV40 origin-dependent DNA replication. In addition to any function in the G0-G1 transition, the data presented suggest that p53 may affect directly the initiation or maintenance of replicative DNA synthesis.     

Molecular diagnostics in a teacup: Non-Instrumented Nucleic Acid Amplification (NINA) for rapid, low cost detection of Salmonella enterica

We report on the use of a novel non-instrumented platform to enable a Loop Mediated isothermal Amplification(LAMP) based assay for Salmonella enterica.Heat energy is provided by addition of a small amount(<150 g) of boiling water,and the reaction temperature is regulated by storing latent energy at the melting temperature of a lipid-based engineered phase change material.Endpoint classification of the reaction is achieved without opening the reaction tube by observing the fluorescence of sequence-specific FRET-based assimilating probes with a simple handheld fluorometer.At or above 22℃ ambient temperature the non-instrumented devices could maintain reactions above a threshold temperature of 61℃ for over 90 min-significantly longer than the 60 min reaction time.Using the simple format,detection limits were less than 20 genome copies for reactions run at ambient temperatures ranging from 8 to 36℃.When used with a pre-enrichment step and non-instrumented DNA extraction device,trace contaminations of Salmonella in milk close to 1 CFU/mL could be reliably detected.These findings illustrate that the non-instrumented amplification approach is a simple,viable,low-cost alternative for field-based food and agricultural diagnostics or clinical applications in developing countries.