(n.) A white amorphous horny substance forming the harder part of the outer integument of insects, crustacea, and various other invertebrates; entomolin.
Example Sentences:
(1) The effect of O-(carboxymethyl)chitins (CM-chitins) on the activation of mouse-peritoneal macrophages in vivo and their mitogenic activity on mouse spleen-cells were investigated.
(2) The pH activity profile, cofactor requirements, and kinetic parameters of the endogenously activated chitin synthase were identical to those of the trypsin-activated enzyme in protoplast membranes.
(3) Results obtained from isotopic dilution experiments are consistent with the operation of the chitin pathway as it has been established in fungal preparations.
(4) The significance of these results is discussed in connection with the mechanism of chitin synthesis and cell wall morphogenesis in S. cerevisiae.
(5) Here we show that the nodulation genes of this bacterium determine the production of a large family of Nod-factors which are N-acylated chitin pentamers carrying a variety of substituents.
(6) In a permeabilized-cell assay, Oct-Gln-UPOC had a 10-fold-lower inhibitory activity toward chitin synthetase than did the Oct-Lys-UPOC analog.
(7) The preparation yielded an apparent Km of 3.9 mg chitin ml-1 [17.6 mM-N-acetylglucosamine (GlcNAc) equivalents] and V of 2.3 nmol GlcNAc formed min-1 (mg protein)-1.
(8) In the case of the [14C]chitin synthesized, which does not show inhibition by alpha factor, the lowering of the specific activity of the precursor is exactly compensated for by an increased rate of chitin synthesis caused by alpha factor.
(9) Chitin derivatives are also used in things like contact lens, surgical stitches and artificial skin.
(10) The inhibitor was effective against crude or purified (chitosome) preparations of chitin synthetase.
(11) After 3 h incubation with tioconazole, 1 microgram ml-1, the incorporation of the radiolabelled glucose into chitin of intact cells and regenerating spheroplasts of C. albicans was inhibited by 43% and 30%, respectively.
(12) Electron microscopy has revealed that chitin from a representative selection of insect orders (plus one crustacean and one arachnid) is localized in crystallites about 2.8 nm across.
(13) When dividing cells of Saccharomyces cerevisiae were exposed to the polysaccharide-binding dye Congo red, the walls and septa became sites of chitin accumulation.
(14) Partially O-hydroxyethylated chitin (glycol chitin) was used as a substrate in the purification and characterization of this enzyme.
(15) In view of the small molecular size and high lipid solubility of methyl mercury and the lipophilic properties of the chitin-protein exoskeleton of the lobster, it is likely that significant uptake directly from the water as well as storage of absorbed methyl mercury occurred in the tail region.
(16) This confirmed that S. pombe cell wall is devoid of chitin.
(17) Adjuvant activity of chitin derivatives was examined in guinea-pigs and mice.
(18) DFB inhibits chitin synthesis and growth of imaginal epidermis in insects and suppresses melanogenesis and uptake of nucleosides in mouse melanoma cells, but the means of cell growth regulation and the role of metabolism of DFB in such regulation have not been established.
(19) These microfibers have a diameter of 80 A and may consist of chitin crystallites surrounded by a matrix coat.
(20) Chemical analysis of adult females of Onchocerca gibsoni gave estimated chitin contents of 200-500 micrograms (g dry weight)-1.
Polymer
Definition:
(n.) Any one of two or more substances related to each other by polymerism; specifically, a substance produced from another substance by chemical polymerization.
Example Sentences:
(1) Five days later, the animals were randomly assigned to one of four treatment groups: Group 1 received intracranial implantation of controlled-release polymers containing dexamethasone; Group 2 received intraperitoneal implantation of controlled-release polymers containing dexamethasone; Group 3 received serial intraperitoneal injections of dexamethasone; and Group 4 received sham treatment.
(2) In spite of important differences in size, chemical composition, polymer density, and configuration, biological macromolecules indeed manifest some of the essential physical-chemical properties of gels.
(3) The acetonitrile extract is concentrated and analyzed by HPLC, using a new polymer-based column, and detected by UV spectroscopy at 270 nm.
(4) These results suggest that glomerular IgA are IgA polymers and decreased hepatic clearance of hepatic IgA polymers may be responsible for the glomerular deposition of IgA.
(5) A method for the introduction of side chains containing isonitrile (isocyanide, functional group) on the backbone of polysaccharides and other hydroxylic polymers was developed.
(6) He knows polymer notes from travels in Australia, where they were first introduced in 1988, and he wants Britain to "move with the times" too.
(7) Poly(ortho ester) bioerodible polymers are suitable materials for the topical administration of a wide variety of therapeutic agents; varying the nature and amounts of excipients physically incorporated into the polymer will vary the erosion rates from a few hours to many months.
(8) By performing countercurrent distribution in the presence of a polymer-ligand, the protein that binds the polymer-ligand can be separated from a heterogenous mixture.
(9) Pulse labeling of the polymer with [2-3H]adenosine was also maximal at the same time points.
(10) Charged polymers, known to alter cell surface characteristics, reversibly inhibit the intercellular communication required in kidney tubule induction.
(11) A novel type of ion exchanger was prepared by multipoint covalent binding of polystyrene chains onto the surface of porous silica followed by polymer-analogous modification of the bonded layer.
(12) Another 52 received a 100-g (nonfasting) glucose polymer screening test followed by a 100-g glucose polymer tolerance test.
(13) The important role of the exocellular polymers for the structure, size and density of flocs can be well illustrated.
(14) A small number of children with protracted diarrhoea, who have severe mucosal injury may not be able to handle even starch and may require diets based on short chain glucose polymers.
(15) Rather, assembly of sIgM into polymers and their subsequent secretion are prevented in B lymphocytes by preceding targeting of monomeric sIgM to degradation.
(16) The neutral polymer was devoid of type 6 activity although it was serologically active.
(17) The tissue reaction was more severe for polymers having a higher rate of degradation.
(18) Control experiments with other constructs (e.g., allopurinol riboside linked to the mannose-free polymer) confirmed that the enhancement of activity was indeed achieved by means of the mannose homing device.
(19) Of the tested polymers, only polyvinyl methylacetamide and dextran inhibit a decrease in the level of mitochondrial enzyme activity which develops with administration of endotoxin.
(20) At different degrees of DNA damage, the average length of the poly-ADP-ribose chain did not practically alter, thus suggesting the increase in the number of polymer binding sites in the histones.