Search results for "genetics [Genetic Variation]"
showing 10 items of 3029 documents
Methyl 3-(4-methoxyphenyl)prop-2-enoate
2001
The title molecule, C(11)H(12)O(3), is almost planar, with an average deviation of the C and O atoms from the least-squares plane of 0.146(4)A. The geometry about the C=C bond is trans. The phenyl ring and -COOCH(3) group are twisted with respect to the double bond by 9.3(3) and 5.6(5) degree, respectively. The endocyclic angle at the junction of the propenoate group and the phenyl ring is decreased from 120 degree by 2.6(2) degree, whereas two neighbouring angles around the ring are increased by 2.3(2) and 0.9(2) degree. This is probably associated with the charge-transfer interaction of the phenyl ring and -COOCH(3) group through the C=C double bond. The molecules are joined together thro…
Tin compounds interaction with membranes of egg lecithin liposomes.
2007
This work is a continuation of earlier research concerning the influence of tin compounds on the dynamic properties of liposome membranes produced with lecithin hen egg yolks (EYL). The experiments were carried out at room temperature (about 25 ∞C). Four tin compounds were chosen, including three organic ones, (CH3)4Sn, (C2H5)4Sn and (C3H7)3SnCl, and one inorganic, SnCl2. The investigated compounds were admixed to water dispersions of liposomes. The content of the admixture changed within the range 0 mol-% to 11mol-% in proportion to EYL. Two spin probes were used in the experiment: 2,2,6,6-tetramethylpiperidine- 1-oxyl (TEMPO) and 2-ethyl-2-(15-methoxy-15-oxopentadecyl)-4,4-dimethyl-3-oxaz…
Two phosphonodehydrotripeptides: Boc0–Gly1–Δ(Z)Phe2–α‐Abu3PO3Me2 and Boc0–Gly1–Δ(Z)Phe2–α‐Nva3PO3Et2
2012
The present paper reports the crystal structures of two short phosphonotripeptides (one in two crystal forms) containing one ΔPhe (dehydrophenylalanine) residue, namely dimethyl (3-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}propyl)phosphonate, Boc0–Gly1–Δ(Z)Phe2–α-Abu3PO3Me2, C21H32N3O7P, (I), and diethyl (4-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}butyl)phosphonate, Boc0–Gly1–Δ(Z)Phe2–α-Nva3PO3Et2, as the propan-2-ol monosolvate 0.122-hydrate, C24H38N3O7P·C3H8O·0.122H2O, (II), and the ethanol monosolvate 0.076-hydrate, C24H38N3O7P·C2H6O·0.076H2O, (III). The crystals of (II) and (III) are isomorphous but differ in the type of solvent. The phosphono gr…
Fatty Acid Composition in the Lipids of some Marine Chiorococcales and Eustigmatales
1989
Abstract The fatty acid composition in the lipids of six coccoid microalgae species (≈ 2 μm in diameter) was investigated. In addition to analyses of ultrastructure and pigment content, lipid composition is shown to be a chemotaxonomic tool in the classification of algae. The four species of Chiorococcales (Chlorophyceae) - the marine species as well as the fresh water species, both kept in artificial seawater - contain a fatty acid composition resembling that of Chlorella spp. and of green leaves of higher plants. The fatty acid pattern is characterized as lacking in C20 acids but containing large amounts of C 16 and C 18 polyunsaturated fatty acids, hexadecatrienic acid (16 :3) and a-lino…
Relationships between metabolic fluxes and enzyme amino acid composition
2013
AbstractMetabolic fluxes are a key parameter of metabolic pathways being closely related to the kinetic properties of enzymes and could be conditional on their sequence characteristics. This study examines possible relationships between the metabolic fluxes and the amino acid (AA) composition (AAC) for enzymes from the yeast Saccharomyces cerevisiae glycolysis pathway. Metabolic fluxes were quantified by the COPASI tool using the kinetic models of Hynne and Teusink at 25 mM, 50 mM, and 100 mM of external glucose or employing literature data for cognate kinetic or stoichiometric models. The enzyme sequences were taken from the UniProtKB, and the AAC computed by the ExPASy/ProtParam tool. Mul…
Discriminative features of type I and type III secreted proteins from Gram-negative bacteria
2006
AbstractThe amino acid composition of sequences and structural attributes (α-helices, β-sheets) of C-and N-terminal fragments (50 amino acids) were compared to annotated (SWISS-PROT/ TrEMBL) type I (20 sequences) and type III (22 sequences) secreted proteins of Gram-negative bacteria.The discriminant analysis together with the stepwise forward and backward selection of variables revealed the frequencies of the residues Arg, Glu, Gly, Ile, Met, Pro, Ser, Tyr, Val as a set of strong (1-P < 0.001) predictor variables to discriminate between the sequences of type I and type III secreted proteins with a cross-validated accuracy of 98.6–100 %. The internal and external validity of discriminant…
Association of model peptides and dehydropeptides: N-acetyl-L-butyrine and (Z)-dehydrobutyrine N',N'-dimethylamides.
2006
These comparative studies on the aggregation behaviour of Ac-(Z)-DeltaAbu-NMe(2) and Ac-L-Abu-NMe(2) in carbon tetrachloride were performed by the analysis of their FTIR spectra and by theoretical calculations. The percentage of the monomeric form (alpha) decreased as concentration increased and this occurred to a higher degree for the (Z)-DeltaAbu derivative than for its saturated analogue. The dimerization constant K(D), calculated on the basis of the intensity of the monomer and associate bands in the nu(s)(N-H) vibration region, is by three orders of magnitude larger for Ac-(Z)-DeltaAbu-NMe(2) than for Ac-L-Abu-NMe(2). The obtained dimer geometries of the dehydro- compound were calculat…
Influence of Cl/Br substitution on the stereochemical peculiarities of copper(I) pi-complexes with the 1-allyl-2-aminopyridinium cation.
2003
By using alternating-current electrochemical synthesis, crystals of the CuI π-complexes bis(1-allyl-2-aminopyridinium) di-μ-chloro-bis[chlorocopper(I)], (C8H11N2)2[Cu2Cl4] or [H2NC5H4NC3H5][CuCl2], and bis(1-allyl-2-aminopyridinium) di-μ-(chloro/bromo)-bis[(chloro/bromo)copper(I)], (C8H11N2)2[Cu2Br2.2Cl1.8] or [H2NC5H4NC3H5][CuBr1.10Cl0.90], have been obtained and structurally investigated. In each of the isostructural (isomorphous) compounds, the distorted tetrahedral Cu environment involves three halide atoms and the C=C bond of the ligand. Both compounds reside on inversion centres, and the dimeric [Cu2 X 4·2H2NC5H4NC3H5] units are bonded into a three-dimensional structure by N—H...X hyd…
Bimodal Effect of Amphiphilic Biocide Concentrations on Fluidity of Lipid Membranes
1996
Abstract Using the spin label method (ESR) it has been shown that biologically active, amphiphilic compounds (quaternary ammonium salts -AS) containing polar heads with single and double positive charge caused, at low concentrations, decrease fluidity of liposome membranes formed with egg yolk lecithin (EYL). At higher concentrations an increase in fluidity was observed. With compounds having a single positive charge minimum fluidity of membrane structure occurs in the range of 1 to 3%, with compounds containing double positive charge -in the range of 4 -6 % . That effect does not depend on polar head size and length of alkyl chains of the AS used. Analysis of the electrostatic interaction …
The morphology of block copolymer micelles in supercritical carbon dioxide by small-angle neutron and x-ray scattering
1997
Above its critical point, carbon dioxide forms a super-critical fluid, which promises to be an environmentally responsible replacement for the organic solvents traditionally used in polymerizations. Many lipophilic polymers such as polystyrene (PS) are insoluble in CO2, though polymerizations may be accomplished via the use of PS-fluoropolymer stabilizers, which act as emulsifying agents. Small-angle neutron and X-ray scattering have been used to show that these molecules form micelles with a CO2-phobic PS core and a CO2-philic fluoropolymer corona. When the PS block was fixed in length and the fluorinated corona block was varied, the number of block copolymer molecules per micelle (six to …