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81.
Ying Cao Jun Adachi Axel Janke Svante Pääbo Masami Hasegawa 《Journal of molecular evolution》1994,39(5):519-527
The phylogenetic relationships among Primates (human), Artiodactyla (cow), Cetacea (whale), Carnivora (seal), and Rodentia (mouse and rat) were estimated from the inferred amino acid sequences of the mitochondrial genomes using Marsupialia (opossum), Aves (chicken), and Amphibia (Xenopus) as an outgroup. The overall evidence of the maximum likelihood analysis suggests that Rodentia is an outgroup to the other four eutherian orders and that Cetacea and Artiodactyla form a clade with Carnivora as a sister taxon irrespective of the assumed model for amino acid substitutions. Although there remains an uncertainty concerning the relation among Artiodactyla, Cetacea, and Carnivora, the existence of a clade formed by these three orders and the outgroup status of Rodentia to the other eutherian orders seems to be firmly established. However, analyses of individual genes do not necessarily conform to this conclusion, and some of the genes reject the putatively correct tree with nearly 5% significance. Although this discrepancy can be due to convergent or parallel evolution in the specific genes, it was pointed out that, even without a particular reason, such a discrepancy can occur in 5% of the cases if the branching among the orders in question occurred within a short period. Due to uncertainty about the assumed model underlying the phylogenetic inference, this can occur even more frequently. This demonstrates the importance of analyzing enough sequences to avoid the danger of concluding an erroneous tree. 相似文献
82.
Sheldon Milstien Naoki Sakai Bruce J. Brew †Charles Krieger ‡James H. Vickers §Kuniaki Saito §Melvyn P. Heyes 《Journal of neurochemistry》1994,63(3):1178-1180
Abstract: Nitric oxide has been proposed to mediate cytotoxic effects in inflammatory diseases. To investigate the possibility that overproduction of nitric oxide might play a role in the neuropathology of inflammatory and noninflammatory neurological diseases, we compared levels of the markers of nitric oxide, nitrite plus nitrate, in the CSF of controls with those in patients with various neurologic diseases, including Huntington's and Alzheimer's disease, amyotrophic lateral sclerosis, and HIV infection. We found that there were no significant increases in the CSF levels of these nitric oxide metabolites, even in patients infected with HIV or in monkeys infected with poliovirus, both of which have significantly elevated levels of the neurotoxin quinolinic acid and the marker of macrophage activation, neopterin. However, CSF quinolinic acid, neopterin, and nitrite/nitrate levels were significantly increased in a small group of patients with bacterial and viral meningitis. 相似文献
83.
Keisuke Tsutsumi Masami Niwa Naoki Kitagawa Sei-ich Yamaga Takeo Anda †Akihiko Himeno ‡Takaya Sato Humayun Khalid Kohtaro Taniyama Shobu Shibata 《Journal of neurochemistry》1994,63(6):2240-2247
Abstract: We identified and characterized 125I-endothelin-1 (125I-ET-1) binding sites in tumor capillaries isolated from human glioblastomas, using the quantitative receptor autoradiographic technique with pellet sections. Quantification was done using the computerized radioluminographic imaging plate system. High-affinity ET receptors were localized in capillaries from glioblastomas and the surrounding brain tissues (KD = 4.7 ± 1.0 × 10?10 and 1.6 ± 0.3 × 10?10M, respectively; Bmax = 161 ± 38 and 140 ± 37 fmol/mg, respectively; mean ± SEM, n = 5). BQ-123, a selective antagonist for the ETA receptor, potently competed for 125I-ET-1 binding to sections of the microvessels with IC50 values of 5.1 ± 0.3 and 5.1 ± 1.5 nM, and 10?6M BQ-123 displaced 84 and 58% of ET binding to capillaries from tumors and brains, respectively. In addition, competition curves obtained in the presence of increasing concentrations of ET-3 showed two components (IC50 = 5.7 ± 2.5 × 10?10 and 1.4 ± 0.2 × 10?6M for tumor microvessels, 1.8 ± 0.6 × 10?10 and 1.1 ± 0.3 × 10?6M for brain microvessels, respectively). Our results indicate that (a) the method we used is simple and highly sensitive for detecting and characterizing various receptors in tumor capillaries, especially in the case of a sparse specimen, and (b) capillaries in glioblastomas express specific high-affinity ET binding sites, candidates for biologically active ET receptors, which predominantly belong to the ETA subtype. 相似文献
84.
Induction of G protein-coupled peptide receptor EBI 1 by human herpesvirus 6 and 7 infection in CD4+ T cells. 总被引:5,自引:3,他引:2 下载免费PDF全文
EBI 1, a putative lymphocyte-specific G protein-coupled peptide receptor, was induced by human herpesvirus 6 or 7 infection in CD4+ T cells, and its expression increased early after infection and reached a plateau at 48 h. The induction of the EBI 1 gene by human herpesvirus 6 or 7 infection was not mediated by soluble factors but by the virus itself. Deduced from comparisons of the amino acid sequences among members of the G protein-coupled receptor superfamily, these findings suggest that EBI 1 may be a member of the leukocyte chemotactic peptide receptor family. 相似文献
85.
Evolution of HCN from both rice ( Oryza sativa ) and cocklebur ( Xanthium pennsylvanicum ) seeds increased during a pre-germination period and preceded the evolution of (C2 H4 ). These two species were adopted as the representatives of starchy and fatty seeds, respectively. Ethylene promotes seed germination of many species. However, HCN evolution declined abruptly when the radicles emerged and before the peak in C2 H4 evolution. More-over, both rice and soybean ( Glycine max ) seeds showed some activity of β-cyanoalanine synthase (CAS, EC 4.4.1.9) even in the unimbibed dry state. The activities of CAS in the lower seed of cocklebur and in soybean seeds increased rapidly after emergence of the radicle. However, the CAS of rice seeds, with high activity in the dry state, exhibited a bimodal change, gradually decreasing until radicle emergence had occurred, but then increaing. It is thus likly that HCN evolution during initial imbibition may be derived from cyanogenic reserves and controlled by both pre-existing and subsequently-developing CAS. The exogenous application of C2 H4 stimulated the activities of CAS in both rice and upper cocklebur seeds and reduced their cyanogen contents. Therefore, the decline of HCN evolution after germination seems to be due to the increased activities of CAS by endogenously produced C2 H4 . 相似文献
86.
Brassinolide-Induced Elongation of Inner Tissues of Segments of Squash (Cucurbita maxima Duch.) Hypocotyls 总被引:1,自引:0,他引:1
Brassinolide (BR) stimulated elongation of etiolated squashhypocotyl segments with outer tissues removed, as well as thatof unpeeled segments, while IAA has no effect on peeled segments.BR changed the mechanical properties of cell walls of the innertissue. The inner tissue is probably the target tissue in BR-inducedelongation.
1Dr. Susumu Kuraishi died in 1993. 相似文献
87.
88.
Naoko Miyano-Kurosaki Hideki Nakashima Koji Ichiyama Kazuhiko Inazawa Hidenori Tabata Hideyuki Tanabe Kiyotaka Ohnishi Hiroshi Mizusawa Yukako Ohshiro Naoki Yamamoto 《Microbiology and immunology》1994,38(10):813-818
A subclonal cl.1–14 cell was established from a monocytic cell line U937 by a limiting dilution method. The anti-HIV-1 activity of some antiviral compounds was evaluated in HIV-1-infected cl.1–14 cells. The results demonstrated that although AZT was a potent inhibitor of HIV-1 replication in cl.1–14 cells, its 50% effective concentration (EC50) values was 80 times higher than that in HIV-1 infected MT-4 cells; the EC50 of AZT was 0.16 μM and 0.002 μM in cl.1–14 and MT-4 cells, respectively. In contrast, the anti-HIV-1 activity of ddA, ddI and ddC in cl.1–14 cells was comparable to that in MT-4 cells. The antiviral activity of nevirapine, dextran sulfate, curdlan sulfate and T22 did not differ significantly between the cl. 1–14 and MT-4 cells. The antiviral activity of several compounds in the HIV-1-infected cl.1–14 cells was similar to that in the HIV-1jr -fl -infected human peripheral macrophages. Our results suggest that cl.1–14 cell cultures are very useful for estimating antiviral activity and more advantageous than the use of peripheral blood macrophages. 相似文献
89.
Kazuo Ohtsuka Katsuhiko Hasegawa Kazunari Sato Katsumitsu Arai Hisami Watanabe Hitoshi Asakura Toru Abo 《Microbiology and immunology》1994,38(8):677-683
Two major populations of extrathymically differentiated T cells exist in the liver and intestine. Such T cells in the liver have TCR of intermediate intensity (i.e., intermediate TCR cells) and constitutively express IL-2 receptor β-chain (IL-2Rβ), whereas those in the intestine, especially intraepithelial lymphocytes, have TCR of bright intensity, consisting of a mixture of IL-2Rβ+ and IL-2Rβ–. All mature thymocytes and thymus-derived T cells seen in the peripheral immune organs are TCR-bright+IL-2Rβ– under resting conditions. When the expression pattern of adhesion molecules, including CD44, L-selectin, LFA-1 and ICAM-1, was compared among these T-cell populations, they displayed quite unique patterns of expression. All extrathymic T cells in the liver, intestine, and even other organs were CD44+L-selectin– LFA-1++ICAM-1+, whereas thymocytes and thymus-derived T cells were CD44– L-selectin+LFA-1+ICAM-1–. This inverted expression of adhesion molecules between extrathymic T cells and thymus-derived T cells might be associated with their unique tissue-localization. 相似文献
90.
Phylogenetic place of guinea pigs: no support of the rodent-polyphyly hypothesis from maximum-likelihood analyses of multiple protein sequences 总被引:3,自引:2,他引:1
Graur et al.'s (1991) hypothesis that the guinea pig-like rodents have an
evolutionary origin within mammals that is separate from that of other
rodents (the rodent-polyphyly hypothesis) was reexamined by the
maximum-likelihood method for protein phylogeny, as well as by the
maximum-parsimony and neighbor-joining methods. The overall evidence does
not support Graur et al.'s hypothesis, which radically contradicts the
traditional view of rodent monophyly. This work demonstrates that we must
be careful in choosing a proper method for phylogenetic inference and that
an argument based on a small data set (with respect to the length of the
sequence and especially the number of species) may be unstable.
相似文献