A schistosome [beta] subunit remodels inactivation of a calcium channel _via_ an N-terminal polyacidic motif

The beta subunit of high voltage-activated Ca (Cav) channels targets the pore forming [alpha]~1~ subunit to the plasma membrane and defines the biophysical phenotype of the Cav channel complex. Cav channel inactivation following activation and opening is tightly regulated and is an essential property that not only prevents excessive entry of Ca^2+^ into the cell but may also have functions in signal transduction. The [beta] subunit modulates Ca^2+^-dependent and voltage-dependent components of Cav channel inactivation via its interaction with the I-II linker of the [alpha]~1~ subunit. Here, using Cav2.3 and whole-cell patch-clamp, we show that a [beta] subunit from the human parasite _Schistosoma mansoni_ ([beta]~Sm~) accelerates inactivation via a unique, long N-terminal polyacidic motif (NPAM). The accelerating effect of NPAM-containing subunits, both native ([beta]~Sm~)and chimeric mammalian [beta]~1b~, [beta]~2a~ and [beta]~3~ subunits to which NPAM had been attached, was only apparent when Ca^2+^ was internally buffered with BAPTA (5 mM) or when Ba^2+^ was used as the charge carrier, two commonly used strategies to eliminate Ca^2+^/calmodulin dependent inactivation. These results indicate that calmodulin is not involved. In addition to accelerating inactivation, NPAM-containing [beta] subunits significantly reduced current density with respect to their non NPAM-bearing counterparts. Interestingly, when the amino acids N terminal to NPAM were deleted, inactivation of Cav2.3 currents was faster than in the presence of the entire N-terminal portion of the [beta]~Sm~ subunit, as if the pre-NPAM region counteracts the effect of NPAM. Presence of NPAM also resulted in currents that activated faster, suggesting that NPAM increases open channel probability. However, NPAM does not modulate inactivation gating. In summary, this study identifies a structural determinant of Cav channel inactivation that is entirely unlike those previously known

Calcium channel β subunits differentially modulate recovery of the channel from inactivation

AbstractWe examined the effects of calcium channel β subunits upon the recovery from inactivation of α1 subunits expressed in Xenopus oocytes. Recovery of the current carried by the L-type α1 subunit (cyCav1) from the jellyfish Cyanea capillata was accelerated by coexpression of any β subunit, but the degree of potentiation differed according to which β isoform was coexpressed. The Cyanea β subunit was most effective, followed by the mammalian b3, b4, and β2a subtypes. Recovery of the human Cav2.3 subunit was also modulated by β subunits, but was slowed instead. β3 was the most potent subunit tested, followed by β4, then β2a, which had virtually no effect. These results demonstrate that different β subunit isoforms can affect recovery of the channel to varying degrees, and provide an additional mechanism by which β subunits can differentially regulate α1 subunits

Tests of related forward-camber airfoils in the variable-density wind tunnel

A recent investigation of numerous related airfoils indicated that positions of camber forward of the usual location resulted in an increase of the maximum lift. As an extension of this investigation, a series of forward-camber airfoils has been developed, the members of which show airfoil characteristics superior to those of the airfoils previously investigated. The primary object of this report is to present fully corrected results for airfoils in the useful range of shapes. With the data thus made available, an airplane designer may intelligently choose the best possible airfoil-section shape for a given application and may predict to a reasonable degree the aerodynamic characteristics to be expected in flight from the section shape chosen

Surfaces, depths and hypercubes: Meyerholdian scenography and the fourth dimension

An appreciation of Meyerhold’s engagement with theatrical space is fundamental to understanding his directorial and pedagogic practice. This article begins by establishing Meyerhold’s theoretical and practical engagement with theatre as a fundamentally scenographic process, arguing for a reconceptualisation of the director as ‘director-scenographer’. Focusing on the construction of depth and surface in Meyerholdian theatre, the article goes on to identify trends in the director’s approach to space, with an emphasis on the de-naturalisation of depth on stage. This denaturalisation is seen as taking three forms: the rejection of depth as a prerequisite in theatrical space, the acknowledgement of the two-dimensional surface as surface, and the restructuring of depth space into a series of restricted planes. The combination of these trends indicates a consistent and systematic process of experimentation in Meyerhold’s work. In addition, this emphasis on depth and surface, and the interaction between the two, also highlights the contextualisation of Meyerhold’s practice within the visual, philosophical and scientific culture of the early twentieth century, echoing the innovations in n-dimensional geometry and particularly, the model of the fourth spatial dimension seen in the work of Russian philosopher P. D. Ouspensky

The Second Conference on Lunar Bases and Space Activities of the 21st Century, volume 1

These papers comprise a peer-review selection of presentations by authors from NASA, LPI industry, and academia at the Second Conference (April 1988) on Lunar Bases and Space Activities of the 21st Century, sponsored by the NASA Office of Exploration and the Lunar Planetary Institute. These papers go into more technical depth than did those published from the first NASA-sponsored symposium on the topic, held in 1984. Session topics covered by this volume include (1) design and operation of transportation systems to, in orbit around, and on the Moon, (2) lunar base site selection, (3) design, architecture, construction, and operation of lunar bases and human habitats, and (4) lunar-based scientific research and experimentation in astronomy, exobiology, and lunar geology

The Second Conference on Lunar Bases and Space Activities of the 21st Century, volume 2

These 92 papers comprise a peer-reviewed selection of presentations by authors from NASA, the Lunar and Planetary Institute (LPI), industry, and academia at the Second Conference on Lunar Bases and Space Activities of the 21st Century. These papers go into more technical depth than did those published from the first NASA-sponsored symposium on the topic, held in 1984. Session topics included the following: (1) design and operation of transportation systems to, in orbit around, and on the Moon; (2) lunar base site selection; (3) design, architecture, construction, and operation of lunar bases and human habitats; (4) lunar-based scientific research and experimentation in astronomy, exobiology, and lunar geology; (5) recovery and use of lunar resources; (6) environmental and human factors of and life support technology for human presence on the Moon; and (7) program management of human exploration of the Moon and space