7,159 research outputs found
A survey of thermodynamic properties of the compounds of the element CHNOPS Progress report, 1 Mar. - 30 Jun. 1968
Thermodynamic property data tables for CHNOPS compounds and heats of combustion and formation for organic compounds of biological interes
Survey of thermodynamic properties of the compounds of the elements CHNOPS Sixth preliminary report, 1 Oct. - 31 Dec. 1965
Heat capacity data on polyhydroxy compounds, water, carbon dioxide, and ammonia and vapor pressure data on methane, ammonia, and amino acid
Expression of functional M2 muscarinic acetylcholine receptor in Escherichia coli
The M2 muscarinic acetylcholine receptor mutant (M2 mutant), with a lack of glycosylation sites, a deletion in the central part of the third inner loop, and the addition of a six histidine tag at the C-terminus, was fused to maltose binding protein (MBP) at its N-terminus and expressed in Escherichia coli. The expression level was 0.2 nmol receptor per 100 ml culture, as assessed as [3H]L-quinuclidinyl benzilate ([3H]QNB) binding activity, when the BL 21 strain was cultured at 37 degrees C to a late growth phase and the expression was induced by isopropyl beta-thiogalactoside at 20 degrees C. No [3H]QNB binding activity was detected when it was not fused to MBP or when expression was induced at 37 degrees C instead of 20 degrees C. The MBP-M2 mutant expressed in E. coli showed the same ligand binding activity as the M2 mutant expressed in the Sporodoptera frugiperda (Sf9)/baculovirus system, as assessed as displacement of [(3)H]QNB with carbamylcholine and atropine. The MBP-M2 mutant was solubilized, purified with Co2+-immobilized Chelating Sepharose gel and SP-Sepharose, and then reconstituted into lipid vesicles with G protein Go or Gi1 in the presence or absence of cholesterol. The reconstituted vesicles showed GTP-sensitive high affinity binding for carbamylcholine and carbamylcholine-stimulated [35S]GTP gamma S binding activity in the presence of GDP. The proportion of high affinity sites for carbamylcholine and the extent of carbamylcholine-stimulated [(35)S]GTP gamma S binding were the same as those observed for the M2 mutant expressed in Sf9 cells and were not affected by the presence or absence of cholesterol. These results indicate that the MBP-M2 mutant expressed in E. coli has the same ability to interact with and activate G proteins as the M2 mutant expressed in Sf9, and that cholesterol is not essential for the function of the M2 muscarinic receptor
Magneto-hydrodynamic Simulations of a Jet Drilling an HI Cloud: Shock Induced Formation of Molecular Clouds and Jet Breakup
The formation mechanism of the jet-aligned CO clouds found by NANTEN CO
observations is studied by magnetohydrodynamical (MHD) simulations taking into
account the cooling of the interstellar medium. Motivated by the association of
the CO clouds with the enhancement of HI gas density, we carried out MHD
simulations of the propagation of a supersonic jet injected into the dense HI
gas. We found that the HI gas compressed by the bow shock ahead of the jet is
cooled down by growth of the cooling instability triggered by the density
enhancement. As a result, cold dense sheath is formed around the interface
between the jet and the HI gas. The radial speed of the cold, dense gas in the
sheath is a few km/s almost independent of the jet speed. Molecular clouds can
be formed in this region. Since the dense sheath wrapping the jet reflects
waves generated in the cocoon, the jet is strongly perturbed by the vortices of
the warm gas in the cocoon, which breaks up the jet and forms a secondary shock
in the HI-cavity drilled by the jet. The particle acceleration at the shock can
be the origin of radio and X-ray filaments observed near the eastern edge of
W50 nebula surrounding the galactic jet source SS433.Comment: 30 pages, 16 figure
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