3,542 research outputs found
Comparing and contrasting Escherichia coli and Mycobacterium tuberculosis mechanosensitive channels (MscL) - New gain of function mutations in the loop region
Sequence analysis of 35 putative MscL homologues was used to develop an optimal alignment for Escherichia coli and Mycobacterium tuberculosis MscL and to place these homologues into sequence subfamilies. By using this alignment, previously identified E. coli MscL mutants that displayed severe and very severe gain of function phenotypes were mapped onto the M. tuberculosis MscL sequence. Not all of the resulting M. tuberculosis mutants displayed a gain of function phenotype; for instance, normal phenotypes were noted for mutations at Ala20, the analogue of the highly sensitive Gly22 site in E. coli. A previously unnoticed intersubunit hydrogen bond in the extracellular loop region of the M. tuberculosis MscL crystal structure has been analyzed. Cross-linkable residues were substituted for the residues involved in the hydrogen bond, and cross-linking studies indicated that these sites are spatially close under physiological conditions. In general, mutation at these positions results in a gain of function phenotype, which provides strong evidence for the importance of the loop region in MscL channel function. No analogue to this interesting interaction could be found in E. coli MscL by sequence alignment. Taken together, these results indicate that caution should be exercised in using the M. tuberculosis MscL crystal structure to analyze previous functional studies of E. coli MscL
Supporting information for “Using drones equipped with thermal cameras to locate and count quail individuals and coveys: A case study using Northern Bobwhite Colinus virginianus in Mississippi, USA”
Drone flights were conducted over bobwhite individuals and coveys and information was collected on the date, time of flight, number of individuals estimated in the covey, and number of individuals flushed from the covey (i.e., actual number of individuals). We also report season of flight and the thermal sensor used for each flight. NA denotes that flush or capture was not attempted
Ion energy measurements on MAST using a midplane RFEA
Ion energy measurements have been made in the scrape off layer of the Mega
Amp Spherical Tokamak (MAST) using a midplane retarding field energy analyser
(RFEA) in H-mode plasmas during the inter-edge localised mode (ELM) period and
during type I and type III ELMs. During the inter-ELM period at distances of 3
to 8 cm from the last closed flux surface (LCFS), ion temperatures of 20 to 70
eV have been measured giving an ion to electron temperature ratio of 2 to 7
with a mean of 4. During type III ELMs, an ion temperature of 50 eV has been
measured 3 to 6 cm from the LCFS which decreases to 30 eV at distances 11 to 16
cm from the LCFS. During type I ELMs, an ion temperature of 40 eV has been
measured at a distance of 10 to 15 cm from the LCFS.Comment: 15 pages, 5 figure
Influence of Dilute Acetic Acid Treatments on American Pondweed Winter Buds in the Nevada Irrigation District, California
American pondweed (
Potamogeton nodosus
Poir.) is commonly
found in northern California irrigation canals. The
purpose of this study was to test the hypothesis that exposure
of American pondweed winter buds to dilute acetic acid under
field conditions would result in reduced subsequent biomass
The design, construction and testing of the optics for a 147-cm-aperture telescope
Geodetic optics research for the Air Force Cambridge Research Laboratories (AFCRL) is described. The work consisted mainly of the fabrication of the optical components for a telescope with a 152-cm-diam (60-in.) primary mirror masked down to 147-cm-diam for use by the AFCRL for a lunar ranging experiment. Among the achievements of this contract were the following: completion of the primary and secondary mirrors for a high-quality 147-cm-diam telescope system in eight months from the start of edging the primary; manufacture and testing of a unique center mount for the primary according to an AFCRL design that allowed for a thin-edged and therefore less-massive mirror; and development of a quantitative analysis of the wire test for calculating the departure of the mirror figure from the design figure quickly and accurately after each polishing step. This analysis method in conjunction with a knowledge of polishing rates for given weights and diameters of tools, mirror, and polishing materials should considerably reduce the polishing time required for future large mirrors
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