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...

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...

One of most important elements of Electric Power Systems (EPS) is the transmission line (TL), which is permanently under adverse conditions especially lightning strokes. At the moment, those phenomena have been the root cause of short circuits and the most important cause of mal-operation of transmission line protection relays. Thus, this paper develops the classification of lightning transient...

This paper focuses on the role of frequency spectral tilt (TL) of the voicing source waveform, the glottal turbulent noise and fluctuations of the source spectrum on period-to-period basis in the cognition of paralinguistic features as in suspicious and disappointed renditions. The TL is closely related to duration of the return phase of the differentiated glottal waveform. Perceptual experimen...

Volcanic ash contains thallium (Tl), which is highly toxic to the biosphere. The aim of this study was to determine the Tl concentration in fractions of volcanic ash samples originating from the Eyjafjallajökull volcano. A sequential extraction scheme allowed for a study of element migration in the environment. Differential pulse anodic stripping voltammetry using a flow measuring system was se...