(a.) Spiral; curved, like the spire of a univalve shell.
(a.) Shaped like a snail shell; pertaining to the Helicidae, or Snail family.
(n.) A warped surface which may be generated by a straight line moving in such a manner that every point of the line shall have a uniform motion in the direction of another fixed straight line, and at the same time a uniform angular motion about it.
Example Sentences:
(1) On the other hand, analogies with helicoidal formations in cholesteric liquid crystals strongly support the hypothesis of involvement of self-assembly processes.
(2) A progressive helicoidal motion was generated upon longitudinal flagellum reactivation, whereas a rolling motion with little progression characterized transverse flagellum reactivation.
(3) Such a structure is also consistent with numerous deviations from the ideal helicoidal array.
(4) This secondary structure is the underlying molecular conformation, dictating the formation of the helicoidal architecture of the eggshell.
(5) The vascular activity of two stereoisomers of hepoxilin A3 (HxA3) (8R and 8S) and of its glutathione conjugate, hepoxilin A3-C (HxA3-C) (8R and 8S), was investigated on rat helicoidal strips of thoracic aorta and longitudinal strips of portal vein.
(6) The distribution, development, and functional basis of the helicoidal plane are investigated here, based on quantitative analysis of dental morphology and attrition in 667 human and 60 chimpanzee dentitions.
(7) This study lends support to Osborn's theory of the helicoidal plane development by showing that attrition enhances rather than modifies posteruption molar occlusal planes.
(8) The Na, K, Cl and water content of faeces removed from different parts of the pig helicoidal colon were determined for 1-day-old and adult animals.
(9) The language eclosion then follows during the second year with helicoidalization of mandibular gesture leading to the "form-inform" tongue at about 7 years of age possessing proprioception of a non-fusorial sensory origin--the absence of this would cause it to be at the mercy of the teeth.
(10) The silkmoth chorion is a helicoidally layered, fibrous structure which is constructed in four sequential morphogenetic modes, beginning with the assembly of a thin, low density lamellar framework.
(11) This phenomenon is secondary to an excess plasma N concentration secondary to the cleavage of Na molecule in two parts in the helicoidal tubular lumen of the kidney, followed by N reabsorption and A urinary excretion.
(12) These sperm progress forward rapidly as a result of the propagation of helicoidal waves distally along the flagellum.
(13) Our new data on the plume of Riftia pachyptila show a new type of fibrillar arrangement of the cuticle: 1) three sets of fibrils are arranged in an hexagonal pattern; 2) fibrils in successive plies are rotated by 60 degrees, and the organization of the fibrillar network is interpreted as a discrete helicoid when compared to continuously twisted plywoods; 3) a fourth set of fibrils crosses the hexagonally arranged plies and is oriented perpendicular to the surface of the body.
(14) This paper proposes an overview of the last few years' investigations regarding the helicoid formation in extracellular matrices (ECMs).
(15) Detailed conformational and helicoidal analysis was performed on the solvated form to determine the exact nature of the dynamical model and the exact points of agreement and disagreement with the crystal structure.
(16) The results obtained for a series of six oligomers with repetitive sequences show that, with the exception of the homopolymers (dA)n.(dT)n and (dG)n.(dC)n, all sequences can adopt a variety of conformations characterized by considerable changes in helicoidal parameters and also in sugar puckers which adopt C(2')-endo (falling into 2 classes) or, in the case of pyrimidine nucleotides, O(1')-endo forms.
(17) We treated eight patients who had lesions typical of geographic helicoid peripapillary choroidopathy (GHPC) (also called serpiginous choroidopathy or geographic choroiditis) initially affecting the macula.
(18) Seven men and six women showed a helicoidal affection.
(19) The muscle fiber bundles are disposed in helicoidal trajectories.
(20) Their tails, parallel in monocephalic spermatozoa and helicoid in bicephalic spermatozoa, have two complete axonemal axes.
Helix
Definition:
(n.) A nonplane curve whose tangents are all equally inclined to a given plane. The common helix is the curve formed by the thread of the ordinary screw. It is distinguished from the spiral, all the convolutions of which are in the plane.
(n.) A caulicule or little volute under the abacus of the Corinthian capital.
(n.) The incurved margin or rim of the external ear. See Illust. of Ear.
(n.) A genus of land snails, including a large number of species.
Example Sentences:
(1) The presence of a few key residues in the amino-terminal alpha-helix of each ligand is sufficient to confer specificity to the interaction.
(2) The elongation of helix III with the addition of helix II at the N-terminus somewhat stabilizes the ordered structure.
(3) The C-terminal sequence contains an amphiphilic alpha-helix of four turns which lies on the surface of the beta-barrel.
(4) The chiral intercalators, at micromolar concentrations, inhibit the reaction of EcoRI, but for each enantiomeric pair it is the lambda enantiomer, which binds only poorly to a B-DNA helix, that inhibits EcoRI preferentially.
(5) The melting profile exhibited two transitions--one at about 35 degrees C and one above 50 degrees C. Our spectral data showed that helices I and II were stable during the first transition, and agreed with other data that helix III was the most likely helix to have melted.
(6) The helix axes, penetrating the hydrophobic region of the bilayers, were oriented neither parallel nor perpendicular to the membrane normal.
(7) The structure of the Z-helix antigen was confirmed by circular dichroism (CD) and U.V.
(8) Conformational predictions based on these sequences confirm their structural homology and indicate the probable existence of two beta-turns, one beta-chain and a long alpha-helix in them.
(9) The nogalose and aminoglucose sugars lie in the minor and major grooves, respectively, of the distorted B-DNA double helix.
(10) The latter, which is external and solvent accessible, is associated with a distortion in the alpha-helix centered around Tyr33 which consists of a significant increase in the CO(i-4)-N(i) and CO(i-4)-NH(i) distances relative to those in the rest of the helix, as well as a significant departure in the phi, psi angles of Tyr33 relative to regular helical geometry.
(11) The AFB1 moiety is face-stacked in the major groove with its long axis approximately perpendicular to the helix axis.
(12) MP8 also was conformed as an alpha-helix, but was amphipatic in the sense that the N-terminal half of the molecule was hydrophilic and the C-terminal half hydrophobic.
(13) A lectin, Helix pomatia agglutinin (HPA), was planted at the surface of rat GEN by the perfusion of the isolated left kidney with neuraminidase (NRD) and HPA.
(14) As a basis for the discussion a possible structure for the DNA complex of the phenylated neutral red is considered in which the extra phenyl ring at N-5 of the phenazinium system, protrudes into the large groove of the DNA helix while the tricyclic part of the ligand is inserted between the DNA base-pairs.
(15) The opsin mutations included reversal of a charged pair conserved in all G protein-coupled receptors at the cytoplasmic border of the third transmembrane helix (mutant CD1), replacement of 13 amino acids in the second cytoplasmic loop (mutant CD2), and deletion of 13 amino acids from the third cytoplasmic loop (mutant EF1).
(16) The remaining 26 independently isolated second-site suppressor mutations all mapped within the amino-terminal DNA binding domain of LexA, at positions 22 (situated in the turn between helix 1 and helix 2) and positions 57, 59, 62, 71 and 73.
(17) In subsequent steps, unassociated Y' directs the synthesis of the complementary oligopurine (R') strand forming a new double helix Y'R' that may direct the synthesis of an oligopyrimidine strand, Y, that is expected to be identical to the first strand that started the whole sequence.
(18) Z-DNA antigen was prepared against poly(dG-dC).poly(dG-dC), which had been converted to the Z-helix conformation in high salt and then stabilized by bromination.
(19) Incubation and heating of the polymers in 1 mM Mn2+ caused the spectral shift reported for the left-handed Z-DNA conformation in the alternating copolymer and the change reported for the triple helix in the homopolymer.
(20) To investigate the ability of a protein to accommodate potentially destabilizing amino acid substitutions, and also to investigate the steric requirements for catalysis, proline was substituted at different sites within the long alpha-helix that connects the amino-terminal and carboxyl-terminal domains of T4 lysozyme.