| resonance raman study on the active-site structure of a cooperative hemerythrin. | resonance raman spectra were observed for the oxy and azidomet forms of a cooperative hemerythrin (hr) isolated from lingula unguis and a noncooperative hr from siphonosoma cumanense. the o-o stretching frequency of the oxy derivative of the l. unguis hr was lower in the high-affinity form generated at ph 7.6 than in the low-affinity form generated at ph 6.2, while that of the s. cumanense hr did not change at those two ph values. the fe-o-fe symmetric stretching mode of l. unguis azidomet-hr ex ... | 1992 | 1637834 |
| thermal decomposition of lingula shell apatite. | lingula shell is composed of apatite with a preferred orientation. the shell apatites of lingula unguis(lu) and lingula shantoungensis(ls) were characterized and compared with apatite of human tooth enamel. insight into the lingula apatite was studied by following the change of lattice parameter, transformation to beta-tricalcium phosphate (beta-tcp), and the loss and change of co3, oh, and h2o after heating up to 1,000 degrees c in air and n2 for 24 hours. the oh stretching band was not observe ... | 1991 | 1655174 |
| amino acid sequence of the hemerythrin alpha subunit from lingula unguis. | the amino acid sequence of the alpha subunit of the allosteric hemerythrin from lingula unguis was determined. it consists of 117 amino acid residues. compared with other non-allosteric hemerythrins consisting of identical subunits of 113 amino acid residues, this protein has the deletion of the n-terminal amino acid and the insertion of five amino acids in the same region as in the case of the monomeric myoerythrin from themiste zostericola. as the amino acid sequence of the beta subunit has al ... | 1991 | 1769966 |
| two distinct subunits of hemerythrin from the brachiopod lingula reevii: an apparent requirement for cooperativity in o2 binding. | reported are results on the subunit composition of octameric hemerythrin (hr) from the brachiopod lingula reevii. unlike most other hrs, l. reevii hr shows cooperativity in o2 binding. purified l. reevii hr was found to consist of two different subunits in approximately equimolar proportions. these two subunits differ in molecular weight by approximately 1000. amino acid sequence data for the first 24 residues of the two subunits, labeled alpha and beta, show 70% identity with each other. compar ... | 1991 | 1892823 |
| the amino acid sequence of the beta chain of hemerythrin from lingula unguis. | the amino acid sequence of the beta chain of hemerythrin from lingula unguis was determined. the sequence consists of 117 amino acid residues. the sequence shares 25 amino acid residues in common with other known hemerythrin sequences, including myohemerythrin, with which it shares an insertion of 5 amino acids. this is the first complete sequence from a heteropolymeric hemerythrin. | 1991 | 1946335 |
| orientation of apatite and organic matrix in lingula unguis shell. | the orientation relationship between apatite and organic matrix in shell of lingula unguis (inarticulate brachiopod) was studied. the organic layers, mineralized layers, and decalcified mineralized layers were examined layer by layer using microbeam x-ray diffraction technique. both organic layer and decalcified mineralized layer showed the diffraction pattern of beta-chitin. the degree of orientation of apatite showed correlation to that of beta-chitin: well oriented diffraction patterns of apa ... | 1990 | 2242496 |
| hemerythrin from lingula unguis consists of two different subunits, alpha and beta. | hemerythrin, a non-heme fe-protein, of lingula unguis has an octamer structure. we demonstrated that the protein is composed of two distinct subunits (alpha and beta), in equal amounts by investigation of their composition and partial terminal sequence. the cross-linking reaction of the native protein with dithiobis-(succinimidyl propionate) provided evidence for the presence of a dimer composed of alpha and beta subunits. | 1990 | 2315298 |
| small angle x-ray scattering study on lingula unguis shell. | lingula unguis shell yields a diffuse small angle x-ray scattering which is caused mainly by the scattering from particles of apatite. in this study, the distribution of particles smaller than 500a was analyzed using the small angle x-ray scattering technique. the non-linear guinier plot indicates that the shell contains various sizes of apatite particles ranging about 20-460a. the small granules with size about 20-160a in diameter are located in the marginal part of the shell and progressively ... | 1989 | 2519273 |
| auto-oxidation of lingula unguis and siphonosoma cumanense hemerythrins induced by some perturbants. | auto-oxidation of human adult hemoglobin and siphonosoma cumanense and lingula unguis hemerythrins were investigated in the presence and absence of perturbants. in the presence of urea, there were no drastic increases in auto-oxidation rates for the three proteins. in contrast, thiocyanate and laurate enhanced the auto-oxidation rates remarkably. in the presence of thiol reagents such as pcmb and nem, auto-oxidation rates were enhanced with dissociation into subunit, but not enhanced so much wit ... | 1989 | 2764951 |
| ultrastructural investigations on the anterior adductor muscle of a brachiopoda, lingula unguis. | the brachiopoda, lingula unguis, has a pair of anterior adductors located in the center of the shell. each muscle consists of an opaque and a translucent portion which is constructed of smooth and obliquely-striated muscle respectively. according to our ultrastructural observations, the opaque portion seems to have two types of cells. they differ only in the diameters of their thick myofilaments. the fine structure of their cell organelles resembles each other. we measured the diameters of the t ... | 1988 | 3180255 |
| epitheliomuscular cells in lingula unguis (brachiopoda) and branchiostoma lanceolatum (acrania). | | 1974 | 4474919 |
| nucleotide sequence of 5s ribosomal rna from lingula anatina. a study on the molecular evolution of 5s ribosomal rna from a living fossil. | by chromatography on columns of deae-sephadex a-50 and sephadex g-100, and electrophoresis on polyacrylamide gel, 5s rrna was purified from a low-molecular-weight rna fraction extracted from the total tissues of lingula anatina. complete digests of the 5s rrna with rnase t1 [ec 3.1.4.8] and pancreatic rnase [ec 3.1.4.22] were sequenced by conventional column chromatography procedures. the nucleotide sequence of this rna was determined mainly by a chemical method for sequencing the rna 3' end-lab ... | 1980 | 6780539 |
| nucleotide sequences and evolutional aspect of 5s ribosomal rnas from lingula and silkworm. | ribosomal 5s rnas were highly purified from the total tissues of lingula anatina and the posterior silk glands of bombyx mori. the nucleotide sequences of the rnas were determined by a chemical method for rapidly sequencing on gels of 3' end-labeled rna, with the aid of conventional sequence analysis of the complete rnase digests of the unlabeled rnas. by comparing the sequences with those of several animal and chlorella 5s rrnas, a phylogenic tree of these 5s rrnas was constructed. | 1980 | 7196035 |
| amino-acid sequences of the alpha- and beta-subunits of hemerythrin from lingula reevii. | the complete amino-acid sequences of the alpha- and beta-subunits of hemerythrin from the brachiopod lingula reevii have been determined. these subunits are found in equal proportions in coelomic hemerythrocytes and form an octamer, presumably with an alpha 4 beta 4 composition. both subunits were found to consist of 117 residues and to show 65% sequence identity to each other. sequences of the alpha- and beta-subunits of l. reevii hemerythrin are closely related to their counterparts in hemeryt ... | 1994 | 7947959 |
| promotion of fluorapatite crystallization by soluble-matrix proteins from lingula anatina shells. | | 2004 | 14767966 |
| novel repetitive structures, deviant protein-encoding sequences and unidentified orfs in the mitochondrial genome of the brachiopod lingula anatina. | complete sequence determination of the brachiopod lingula anatina mtdna (28,818 bp) revealed an organization that is remarkably atypical for an animal mt-genome. in addition to the usual set of 37 animal mitochondrial genes, which make up only 57% (16,555 bp) of the entire sequence, the genome contains lengthy unassigned sequences. all the genes are encoded in the same dna strand, generally in a compact way, whereas the overall gene order is highly divergent in comparison with known animal mtdna ... | 2005 | 15980959 |
| mechanical properties of modern calcite- (mergerlia truncata) and phosphate-shelled brachiopods (discradisca stella and lingula anatina) determined by nanoindentation. | we measured distribution patterns of hardness and elastic modulus by nanoindentation on shells of the rhynchonelliform brachiopod mergerlia truncata and the linguliform brachiopods discradisca stella and lingula anatina. the rhynchonelliformea produce calcitic shells while the linguliformea produce chitinophosphatic shells. dorsal and ventral valves, commissure and hinge of the calcitic shell of m. truncata show different nanohardness values (from 2.3 to 4.6 gpa) and e-modulus (from 52 to 76 gpa ... | 2009 | 19729068 |
| contrasts between organic participation in apatite biomineralization in brachiopod shell and vertebrate bone identified by nuclear magnetic resonance spectroscopy. | unusually for invertebrates, linguliform brachiopods employ calcium phosphate mineral in hard tissue formation, in common with the evolutionarily distant vertebrates. using solid-state nuclear magnetic resonance spectroscopy (ssnmr) and x-ray powder diffraction, we compare the organic constitution, crystallinity and organic matrix-mineral interface of phosphatic brachiopod shells with those of vertebrate bone. in particular, the organic-mineral interfaces crucial for the stability and properties ... | 2011 | 20610423 |