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Evolution of the intensive summer oral language proficiency institutes held at the University of Texas at El Paso, beginning in 1984, is discussed. Benefits for participants, including knowledge gained about language testing and improved personal language skills, are noted, and areas for further consideration or improvement in the program are outlined. (MSE)

Cellular life emerged ~3.7billion years ago. With scant exception, terrestrial organisms have evolved under predictable daily cycles owing to the Earth's rotation. The advantage conferred on organisms that anticipate such environmental cycles has driven the evolution of endogenous circadian rhythms that tune internal physiology to external conditions. The molecular phylogeny of mechanisms driving these rhythms has been difficult to dissect because identified clock genes and proteins are not conserved across the domains of life: Bacteria, Archaea and Eukaryota. Here we show that oxidation-reduction cycles of peroxiredoxin proteins constitute a universal marker for circadian rhythms in all domains of life, by characterizing their oscillations in a variety of model organisms. Furthermore, we explore the interconnectivity between these metabolic cycles and transcription-translation feedback loops of the clockwork in each system. Our results suggest an intimate co-evolution of cellular timekeeping with redox homeostatic mechanisms after the Great Oxidation Event ~2.5 billion years ago., Circadian rhythms are considered to be a feature of almost all living cells. When isolated from external stimuli, organisms exhibit self-sustained cycles in behaviour, physiology and metabolism, with a period [...]

Alternative splicing yields novel BMAL2 variants: tissue distribution and functional characterization. Am J Physiol Cell Physiol 283: C103-C114, 2002. First published February 13, 2002; 10.1152/ajpcell.00541. 2001.--The BMAL2 gene encodes a member of the basic helix-loop-helix PER-ARNT-SIM family of transcription factors, which control diverse physiological processes including circadian rhythms. We identified four novel human BMAL2 transcripts that differ by alternative splicing within their N[H.sub.2]-terminal regions. Divergent expression of these and previously reported transcripts was observed among human tissues. The functional consequences of alternative splicing for transcriptional activation by CLOCK:BMAL2 heterodimers were assessed using luciferase reporter gene constructs that contained one of three diurnally regulated promoters, namely, those of the mouse period1, mouse vasopressin, and human plasminogen activator inhibitor-1 genes. These studies revealed that alternative splicing generates BMAL2 isoforms possessing high, medium, low, or no transcriptional activity. Similar results were obtained with each promoter, suggesting that alternative splicing may influence the amplitudes of both central and peripheral oscillators. Indeed, alternative splicing of BMAL2 may provide tissues with a rheostat capable of regulating CLOCK:BMAL2 heterodimer function across a broad continuum of potential transcriptional activities to accommodate varied metabolic demands and physiological roles. circadian clock; cryptochrome; period; plasminogen activator inhibitor-1

Modification of the Per2 clock gene in mPer2Luc reporter mice significantly alters circadian function. Behavioral period in constant dark is lengthened, and dissociates into two distinct components in constant light. Rhythms exhibit increased bimodality, enhanced phase resetting to light pulses, and altered entrainment to scheduled feeding. Mechanistic mathematical modelling predicts that enhanced protein interactions with the modified mPER2 C-terminus, combined with differential clock regulation among SCN subregions, can account for effects on circadian behavior via increased Per2 transcript and protein stability. PER2::LUC produces greater suppression of CLOCK:BMAL1 E-box activity than PER2. mPer2Luc carries a 72 bp deletion in exon 23 of Per2, and retains a neomycin resistance cassette that affects rhythm amplitude but not period. The results show that mPer2Luc acts as a circadian clock mutation illustrating a need for detailed assessment of potential impacts of c-terminal tags in genetically modified animal models. Author summary: Engineered genes that are modified to express bioluminescent signals can be used to monitor cellular processes by reflecting the actual state of the process in real time. For circadian rhythm studies, a widely used reporter model (mPer2Luc) expresses firefly luciferase under the control of the clock gene Period 2 (Per2), encoding a fusion protein (PER2::LUCIFERASE) which produces rhythms of bioluminescence. We present evidence that the engineered protein produces extensive changes in iconic circadian behavioral patterns in mice. The evidence comes from analysis of long-term recordings of circadian behavior in mPer2Luc mice in constant darkness and constant light, together with responsiveness to light pulses and entrainment to restricted food availability. By integrating a well-established mathematical model of circadian rhythm generation in the suprachiasmatic nuclei with the known functional heterogeneity within the nucleus, we recapitulated the observed locomotor behavioral patterns in WT and mPer2Luc mice. Functional alterations to the stability of PER2 protein predicted from the model were substantiated by increased repression strength of PER2::LUC over WT PER2 on CLOCK:BMAL1 transcriptional activation. Therefore, mPer2Luc is a clock mutation that provides new insights into the functional neuroanatomy of the mammalian circadian system and the critical importance of Per2 regulation in rhythm generation. [ABSTRACT FROM AUTHOR]

Reports on a survey taken by the Southwest Conference on Language Teaching of each state on the current status of language proficiency testing requirements at the state level for persons seeking certification in language. Results show that an increasing number of states are presently requiring tests or considering requiring them. (SED)

A role-reversal technique is described to teach cognitive coping skills to a patient with writing phobia. Desensitization scenes and coping strategies for lessening anxiety were presented by the patient to the therapist, resulting in reduced anxiety and an increased ability to write in the presence of other people. (Author/CM)

This Article examines the role of tribal courts in the administration of justice in rural Alaska. This Article begins by describing the relationship between Native tribes in the Lower Forty-Eight [...]