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591.
592.
Is there directional smelling? 总被引:17,自引:0,他引:17
The aim of the present study was to establish the crucial precondition for directional smelling, i.e. the ability of humans to discriminate between odorous stimuli perceived either from the right or from the left side. When the 'pure' odorants hydrogen sulphide or vanillin were used as stimulants localization was random. On the other hand stimulation with carbon dioxide or menthol yielded identification rates of more than 96%. These results established the fact that directional orientation, considering single momentary odorous sensations, can only be assumed, when the olfactory stimulants simultaneously excite the trigeminal somatosensory system. 相似文献
593.
Chymotrypsin gene expression during the intermolt cycle in the shrimpPenaeus vannamei (Crustacea; Decapoda) 总被引:1,自引:0,他引:1
A. Van Wormhoudt D. Sellos A. Donval S. Plaire-Goux G. Le Moullac 《Cellular and molecular life sciences : CMLS》1995,51(2):159-163
InPenaeus vannamei, chymotrypsin is present as two isoenzymes in the hepatopancreas. The enzyme has been localized in F-cells by immunocytochemistry using a specific antibody. By in situ hybridization, with a 510 pb cDNA probe encoding for the first 170 amino acids of the shrimp chymotrypsin, mRNA was localized in the same cells. Gene expression was followed during the intermolt cycle by measuring changes in specific activity in crude extracts, and by the estimation of mRNA levels by Northern blots using the same probe. The increase in specific activity in premolt is preceded in early premolt by an increase in the amount of chymotrypsin mRNA. A second increase is observed in postmolt, suggesting a different mode of regulation of gene expression. 相似文献
594.
Stable nitroxides as lipid antioxidants 总被引:2,自引:0,他引:2
595.
596.
L. Fanuel I. Thamm V. Kostanjevecki B. Samyn B. Joris C. Goffin J. Brannigan J. Van Beeumen J. M. Frère 《Cellular and molecular life sciences : CMLS》1999,55(5):812-818
Two new enzymes which hydrolyse D-alanyl-p-nitroanilide have been detected in Ochrobactrum anthropi LMG7991 extracts. The first enzyme, DmpB, was purified to homogeneity and found to be homologous to the Dap protein produced
by O. anthropi SCRC C1-38 (ATCC49237). The second enzyme, DmpA, exhibits a similar substrate profile when tested on p-nitroanilide derivatives
of glycine and L/D-alanine, but the amounts produced by the Ochrobactrum strain were not sufficient to allow complete purification. Interestingly, the DmpA preparation also exhibited an L-aminopeptidase
activity on the tripeptide L-Ala-Gly-Gly but it was not possible to be certain that the same protein was responsible for both
p-nitroanilide and peptide hydrolysing activities. The gene encoding the DmpA protein was cloned and sequenced. The deduced
protein sequence exhibits varying degrees of similarity with those corresponding to several open reading frames found in the
genomes of other prokaryotic organisms, including Mycobacteria. None of these gene products has been isolated or characterised,
but a tentative relationship can be proposed with the NylC amidase from Flavobacterium sp. K172.
Received 7 December 1998; received after revision 15 March 1999; accepted 22 March 1999 相似文献
597.
Mutations in COL11A2 cause non-syndromic hearing loss (DFNA13) 总被引:13,自引:0,他引:13
McGuirt WT Prasad SD Griffith AJ Kunst HP Green GE Shpargel KB Runge C Huybrechts C Mueller RF Lynch E King MC Brunner HG Cremers CW Takanosu M Li SW Arita M Mayne R Prockop DJ Van Camp G Smith RJ 《Nature genetics》1999,23(4):413-419
We report that mutation of COL11A2 causes deafness previously mapped to the DFNA13 locus on chromosome 6p. We found two families (one American and one Dutch) with autosomal dominant, non-syndromic hearing loss to have mutations in COL11A2 that are predicted to affect the triple-helix domain of the collagen protein. In both families, deafness is non-progressive and predominantly affects middle frequencies. Mice with a targeted disruption of Col11a2 also were shown to have hearing loss. Electron microscopy of the tectorial membrane of these mice revealed loss of organization of the collagen fibrils. Our findings revealed a unique ultrastructural malformation of inner-ear architecture associated with non-syndromic hearing loss, and suggest that tectorial membrane abnormalities may be one aetiology of sensorineural hearing loss primarily affecting the mid-frequencies. 相似文献
598.
599.
Activated T cells regulate bone loss and joint destruction in adjuvant arthritis through osteoprotegerin ligand 总被引:124,自引:0,他引:124
Kong YY Feige U Sarosi I Bolon B Tafuri A Morony S Capparelli C Li J Elliott R McCabe S Wong T Campagnuolo G Moran E Bogoch ER Van G Nguyen LT Ohashi PS Lacey DL Fish E Boyle WJ Penninger JM 《Nature》1999,402(6759):304-309
Bone remodelling and bone loss are controlled by a balance between the tumour necrosis factor family molecule osteoprotegerin ligand (OPGL) and its decoy receptor osteoprotegerin (OPG). In addition, OPGL regulates lymph node organogenesis, lymphocyte development and interactions between T cells and dendritic cells in the immune system. The OPGL receptor, RANK, is expressed on chondrocytes, osteoclast precursors and mature osteoclasts. OPGL expression in T cells is induced by antigen receptor engagement, which suggests that activated T cells may influence bone metabolism through OPGL and RANK. Here we report that activated T cells can directly trigger osteoclastogenesis through OPGL. Systemic activation of T cells in vivo leads to an OPGL-mediated increase in osteoclastogenesis and bone loss. In a T-cell-dependent model of rat adjuvant arthritis characterized by severe joint inflammation, bone and cartilage destruction and crippling, blocking of OPGL through osteoprotegerin treatment at the onset of disease prevents bone and cartilage destruction but not inflammation. These results show that both systemic and local T-cell activation can lead to OPGL production and subsequent bone loss, and they provide a novel paradigm for T cells as regulators of bone physiology. 相似文献
600.
The aim of the present study was to establish the crucial precondition for directional smelling, i.e. the ability of humans to discriminate between odorous stimuli perceived either from the right or from the left side. When the pure odorants hydrogen sulphide or vanillin were used as stimulants localization was random. On the other hand stimulation with carbon dioxide or menthol yielded identification rates of more than 96%. These results established the fact that directional orientation, considering single momentary odorous sensations, can only be assumed, when the olfactory stimulants simultaneously excite the trigeminal somatosensory system. 相似文献