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A very large tooth, found in the region of the second mandibular premolar, in a subject, Jewish immigrant from Iraq, is in all likelihood an expression of a familial trait of disturbances in genesis of the shape of dental buds. The appearance of any primitive realization in this case can be conceivable and it was discussed. 相似文献
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Insulin-like growth factor-I supports proliferation of autocrine thymic lymphoma cells with a pre-T cell phenotype 总被引:4,自引:0,他引:4
R A Gjerset J Yeargin S K Volkman V Vila J Arya M Haas 《Journal of immunology (Baltimore, Md. : 1950)》1990,145(10):3497-3501
We have studied the phenotypic characteristics and growth properties of murine T lymphoma cell lines derived from primary x-ray-induced thymic lymphomas at the earliest stage at which they can be detected, and well before spreading to other organs has occurred. These cell lines serve as model systems for the earliest events in T cell lymphoma induction, before tumor cell progression and spreading to other organs. We find that primary x-ray-induced T cell lymphoma lines have phenotypic characteristics of thymic pre-T cells and show no proliferative response to any of the IL tested nor to other hematopoietic growth factors. However, they do proliferate in response to insulin-like growth factor I (IGF-I) and to a small autocrine peptide distinct from IGF-I, which we term lymphoma growth factor. One of the earliest lesions in T cell lymphoma induction may therefore be an inhibition of differentiation at one of several specific points. In its early stages, T lymphoma cell growth may be restricted to an environment where local concentrations of specific growth factors such as IGF-I or lymphoma growth factor are sufficiently high. 相似文献
36.
M. Rosa Pinol Urs Kägi Claus W. Heizmann Brigitte Vogel Jean-Marc Séquier Werner Haas Willi Hunziker 《Journal of neurochemistry》1990,54(6):1827-1833
Many processes in the CNS depend on calcium. The calcium signal is transduced into an intracellular response via Ca2(+)-binding proteins, including calbindin D-28K. In many laboratories, polyclonal antibodies against chicken intestinal calbindin D-28K have been used to study its localization in the brain (normal and degenerated) of various species, including humans, but some of these antisera cross-reacted with other proteins, including calretinin. We purified recombinant rat brain calbindin D-28K to raise antisera in rabbits and purified a recombinant rat-chicken calbindin D-28K hybrid protein to immunize mice for the generation of monoclonal antibodies. These antisera were highly specific for calbindin D-28K, as demonstrated by two-dimensional Western blotting analysis. Immunohistochemical analyses combined with in situ hybridization studies demonstrated that calbindin D-28K in the Purkinje cells of the cerebellum is independent of vitamin D. The antibodies described here will be important tools for studying the regulation of expression of calbindin D-28K and its biological function in the brain and in the PNS. 相似文献
37.
T L Rosenberry J A Krall T E Dever R Haas D Louvard W C Merrick 《The Journal of biological chemistry》1989,264(13):7096-7099
Biosynthetic incorporation of [3H]ethanolamine into proteins was assessed in the human erythroleukemia cell line K562. A single predominant labeled protein of about 50 kDa was observed following electrophoresis of cell extracts on polyacrylamide gels in the presence of sodium dodecyl sulfate. Subcellular fractionation showed this protein to distribute similarly to a 46-kDa [3H]ethanolamine-labeled protein reported previously (Tisdale, E. J., and Tartakoff, A. M. (1988) J. Biol. Chem. 263, 8244-8252). In particular, the protein was enriched in cytosolic and microsomal fractions relative to plasma membrane and thus did not appear to correspond to the class of proteins with glycoinositol phospholipid anchors, the only post-translational protein modification involving ethanolamine that had been described previously. Two-dimensional polyacrylamide gel analysis involving isoelectric focusing followed by electrophoresis in sodium dodecyl sulfate indicated that the protein was very basic, and nitrocellulose blots of one- and two-dimensional gels subjected to 3H autoradiography and immunostaining with antisera to purified rabbit elongation factor (EF) 1 alpha revealed that the protein was EF-1 alpha. Copurification of rabbit EF-1 alpha and the [3H]ethanolamine-labeled protein from K562 cells further supported this identification. Analysis of tryptic fragments produced from the copurified proteins by reverse-phase high pressure liquid chromatography showed two radiolabeled peptides. Amino acid analysis demonstrated 1 residue of ethanolamine in each peptide, and peptide sequencing revealed that the ethanolamine-containing component(s) was attached to Glu301 and Glu374 in the EF-1 alpha protein sequence deduced from a human EF-1 alpha cDNA. These data confirm a new class of post-translational protein modifications involving ethanolamine. 相似文献
38.
To further our understanding of the protein folding process, it is desirable to examine the structural intermediates (equilibrium and kinetic) that are populated between the statistical coil state and the folded molecule. X-ray crystallography and NMR structural studies are unable to determine long-range distances in proteins under denaturing solution conditions. Nonradiative (F?rster) energy transfer, however, has been shown to be a spectroscopic ruler for the measurement of distance distributions and diffusion between selected sites in proteins under a range of different solution conditions. The distributions of distances between a donor probe at the N-terminal residue and an acceptor attached to one of the four lysine residues (15, 26, 41, 46) of reduced and unfolded (in 6 M guanidine hydrochloride and 20 mM dithiothreitol) bovine pancreatic trypsin inhibitor (BPTI) were measured as a function of temperature. Even in strong denaturant and reducing agent, BPTI does not exist as a statistical coil polypeptide. It appears that nonlocal (long-range) interactions are already beginning to "fold" the protein toward a more compact, native conformation. As the temperature is increased under these conditions, hydrophobic interactions lead to an even more compact structure consistent with the predictions of phase diagrams for globular proteins. 相似文献
39.
E S Haas D W Armbruster B M Vucson C J Daniels J W Brown 《Nucleic acids research》1996,24(7):1252-1259
Although the structure of the catalytic RNA component of ribonuclease P has been well characterized in Bacteria, it has been little studied in other organisms, such as the Archaea. We have determined the sequences encoding RNase P RNA in eight euryarchaeal species: Halococcus morrhuae, Natronobacterium gregoryi, Halobacterium cutirubrum, Halobacteriurn trapanicum, Methanobacterium thermoautotrophicum strains deltaH and Marburg, Methanothermus fervidus and Thermococcus celer strain AL-1. On the basis of these and previously available sequences from Sulfolobus acidocaldarius, Haloferax volcanii and Methanosarcina barkeri the secondary structure of RNase P RNA in Archaea has been analyzed by phylogenetic comparative analysis. The archaeal RNAs are similar in both primary and secondary structure to bacterial RNase P RNAs, but unlike their bacterial counterparts these archaeal RNase P RNAs are not by themselves catalytically proficient in vitro. 相似文献
40.
Relative apparent synapomorphy analysis (RASA). I: The statistical measurement of phylogenetic signal 总被引:10,自引:9,他引:1
We have developed a new approach to the measurement of phylogenetic signal
in character state matrices called relative apparent synapomorphy analysis
(RASA). RASA provides a deterministic, statistical measure of natural
cladistic hierarchy (phylogenetic signal) in character state matrices. The
method works by determining whether a measure of the rate of increase of
cladistic similarity among pairs of taxa as a function of phenetic
similarity is greater than a null equiprobable rate of increase. Our
investigation of the utility and limitations of RASA using simulated and
bacteriophage T7 data sets indicates that the method has numerous
advantages over existing measures of signal. A first advantage is
computational efficiency. A second advantage is that RASA employs known
methods of statistical inference, providing measurable sensitivity and
power. The performance of RASA is examined under various conditions of
branching evolution as the number of characters, character states per
character, and mutations per branch length are varied. RASA appears to
provide an unbiased and reliable measure of phylogenetic signal, and the
general approach promises to be useful in the development of new techniques
that should increase the rigor and reliability of phylogenetic estimates.
相似文献