The trigger loop (TL) in the RNA polymerase (RNAP) active center plays key roles in the reactions of nucleotide addition and RNA cleavage catalyzed by RNAP. The adjacent F loop (FL) was proposed to contribute to RNAP catalysis by modulating structural changes in the TL. Here, we investigate the interplay between these two elements during transcription by bacterial RNAP. Thermodynamic analysis o...

Several methods have been employed to measure telomere length (TL) in human studies. It has been difficult to directly compare the results from these studies because of differences in the laboratory techniques and output parameters. We compared TL measurements (TLMs) by the three most commonly used methods, quantitative polymerase chain reaction (qPCR), flow cytometry with fluorescence in situ ...

The trigger loop (TL) forms a conserved element in the RNA polymerase active centre that functions in the elongation phase of transcription. Here, we show that the TL also functions in transcription initiation and termination. Using recombinant variants of RNA polymerase from Pyrococcus furiosus and a reconstituted transcription system, we demonstrate that the TL is essential for initial RNA sy...

Classical estimation methods (least squares, the method of moments and maximum likelihood) work well in regular cases such as the exponential family, but outliers can have undue in1uence on these methods. We de3ne population trimmed L-moments (TL-moments) and corresponding sample TL-moments as robust generalisations of population and sample L-moments. TL-moments assign zero weight to extreme ob...

Although telomere length (TL) is known to play a critical role in cellular senescence, the relationship of TL to aging and longevity in humans is not well understood. In a large biracial population-based cohort, we tested the hypotheses that elderly persons with shorter TL in peripheral white blood cells have poorer survival, shorter life span, and fewer years of healthy life (YHL). Association...

To elucidate the funciton of the mouse TL antigen in the thymus, we have derived two TL transgenic mouse strains by introducing Tl alpha 2-3 of A strain origin with its own promoter onto a C3H background with no expression of TL in the thymus. These transgenic mouse strains, both of which express high levels of Tla2-3-TL antigen in their thymus, were analyzed for their T cell function with emph...

BACKGROUND Tubal ligation (TL) is recommended for women who have completed their family planning. The existence of the menstrual disorders following this procedure has been the subject of debate for decades. This study was conducted to identify the relationship between tubal ligation and menstrual disorders. MATERIALS AND METHODS A historical cohort study was carried out on 140 women undergoi...

BACKGROUND Tegumentary leishmaniasis (TL) is a disease of skin and/or mucosal tissues caused by Leishmania parasites. TL patients may concurrently carry other pathogens, which may influence the clinical outcome of TL. METHODOLOGY AND PRINCIPAL FINDINGS This review focuses on the frequency of TL coinfections in human populations, interactions between Leishmania and other pathogens in animal mo...

T cell differentiation in human marrow was studied in Dexter type long-term bone marrow cultures. In these cultures, T lymphocyte colony-forming units (TL-CFU), E rosette-forming cells (E+), and T3+, T4+, and T8+ cells (assayed by indirect immunofluorescence) were found to be present for at least 7 weeks. It was investigated whether the existence of T cells in long-term culture resulted from th...

In bacteria, intrinsic termination signals cause disassembly of the highly stable elongating transcription complex (EC) over windows of two to three nucleotides after kilobases of RNA synthesis. Intrinsic termination is caused by the formation of a nascent RNA hairpin adjacent to a weak RNA-DNA hybrid within RNA polymerase (RNAP). Although the contributions of RNA and DNA sequences to terminati...