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21.
22.
Hisashi Miyazaki Masatoshi Iida Yoshimasa Matsunaga Toshihiko Fujii Keiko Nambu Hideki Amejima Yoshinori Oh-e Hideo Furukawa Yukiharu Matsui Yasunobu Sohmura Masahisa Hashimoto 《Biotherapy》1989,1(1-2):47-57
The mode of antitumor action of rHu-TNF was elucidated in BALB/c mice bearing Meth A fibrosarcoma 7 days after transplantation with respect to time course, dose-response relationships and selectivity of the effects. The maximal cytotoxic effect on tumor cells revealed by inhibition of DNA synthesis and maximal lesional effect on tumor vasculature revealed by change in blood pool-size in the tissue were detected at 30 min and I h after administration of rHu-TNF, respectively. The dose-response relationship between cytotoxic and tumoricidal effects of rHu-TNF was irrespective of administration route. ED50s of these antitumor effects afteri.v. administration of rHu-TNF were about 50 times as high as ED50s afteri.t. administration. ED50 ofi.t. given rHu-TNF for vascular effect was about 20 times as high as that for cytotoxicity while ED50 ofi.v. rHu-TNF for vascular effect was only 2–3 times as high as that for cytotoxicity. The whole body autoradiographies with [125I] HSA giveni.v. to see the blood influx into tumor tissue and [14C]thymidine given i.v. to see DNA synthesis in the whole body after administration of rHu-TNF revealed that the distribution of radioactivity was markedly changed in the tumor alone without any detectable change in other whole body tissues.In conclusion, thein vivo antitumor effect of rHu-TNF giveni.t. ori.v., appears to be exerted through the direct action on Meth A sarcoma rather than indirectly on tumor vasculature. Under present conditions, the effect of rHu-TNF in the whole body tissues seems rather selective on cells and vasculature of the tumor. 相似文献
23.
T Iida T Momose T Tamura T Matsumoto F C Chang J Goto T Nambara 《Journal of lipid research》1989,30(8):1267-1279
The complete set of the eight theoretically possible stereoisomeric 3,6,7-trihydroxy-5 beta-cholanic acids, four of which are new, related to hyocholic and muricholic acids were prepared from chenodeoxycholic acid. The principal reactions used were 1) cis-dihydroxylation of delta 6-compounds with osmium tetroxide/N-methylmorpholine N-oxide; 2) trans-dihydroxylation of 6 alpha, 7 alpha-epoxy compounds with boron trifluoride etherate in N,N-dimethyl-formamide; 3) inversion of equatorial 3 alpha-hydroxylated compounds to the corresponding 3 beta-epimers with diethyl azodicarboxylate/triphenylphosphine/formic acid; and 4) stereoselective reduction of 7-keto derivatives with zinc borohydride (or sodium borohydride) and by metallic potassium/tert-amyl alcohol. 相似文献
24.
Bent DNA is needed for recombinational enhancer activity in the site-specific recombination system Cin of bacteriophage P1. The role of FIS protein 总被引:12,自引:0,他引:12
A series of recombinational enhancer mutants was constructed by manipulating the ClaI site between the two FIS binding sites of the Hin enhancer. These mutants include insertions from two to 12 base-pairs and two deletions of one or two base-pairs. Recombinational enhancer activity was found only with four mutants carrying either a four base-pair substitution, ten base-pair insertions or a one base-pair deletion, respectively; two other ten base-pair insertion mutants, however, were inactive, although FIS protein binding was unaffected. So, besides binding of FIS protein to its specific sites within the enhancer sequence and the correct helical positioning of these sites on the DNA, another criterion for enhancer activity must be fulfilled. DNA bending assays identify this requirement as a change of the enhancer DNA conformation, which FIS protein is able to induce and to stabilize. This conformational change of the DNA can be blocked by mutations in the central segment between the two FIS binding sites of the Hin enhancer. This sequence has special functions for the recombinational enhancer activity. 相似文献
25.
H Ohshima S Oguchi H Adachi S Iida H Suzuki T Sugimura H Esumi 《Biochemical and biophysical research communications》1992,183(1):238-244
Nitric oxide (NO) synthase (EC 1.14.23) was purified to homogeneity from bovine cerebrum. The molecular weight of NO synthase was estimated to be 150 kDa by both SDS/PAGE and gel filtration at high salt concentration. For activity, the enzyme required NADPH, Ca2+, calmodulin and tetrahydrobiopterin as cofactors. Rabbit polyclonal antibody to bovine brain NO synthase reacted with 150 kDa NO synthase in various bovine and rat organs, including the brain, pituitary and adrenal glands, but not with that in stimulated macrophages, indicating that there are at least two immunologically distinct NO synthases. 相似文献
26.
Hillary A. Hahm Margot M. Ip Kathleen Darcy Jennifer D. Black Wendy K. Shea Suzanne Forczek Masami Yoshimura Takami Oka 《In vitro cellular & developmental biology. Plant》1990,26(8):803-814
Summary A serum-free primary culture system is described which allows normal rat mammary epithelial cells (RMECs) embedded within
a reconstituted basement membrane to undergo extensive growth and functional differentiation as detected by synthesis and
secretion of the milk products casein and lipid. RMECs isolated from mammary glands of immature virgin rats were seeded within
an extracellular matrix preparation derived from the Engelbreth-Holm-Swarm sarcoma and cultured in a serum-free medium consisting
of Dulbecco's modified Eagle's medium-F12 containing insulin, prolactin, progesterone, hydrocortisone, epidermal growth factor,
bovine serum albumin, transferrin, and ascorbic acid. Casein synthesis and secretion were documented at the electron microscopic
level as well as by an enzyme-linked immunosorbent assay (ELISA) assay using a polyclonal antibody against total rat caseins.
Numerous secretory vesicles with casein micelles were noted near the apical surface of the RMECs, and secreted casein was
observed in the lumen. These ultrastructural data were confirmed by the ELISA assay which showed that microgram amounts of
casein per well were synthesized by the RMECs and that the amount of casein increased with time in culture. Using immunoblot
analysis it was demonstrated that the full complement of casein proteins was synthesized. In addition to casein protein, β-casein
mRNA levels were shown to increase with time. Synthesized lipid was detected at both the light and electron microscopic levels.
Phase contrast photomicrographs demonstrated extensive intracellular lipid accumulation within the ductal and lobuloalveolarlike
colonies, and at the electron micrograph level, lipid droplets were predominantly localized near the apical surface of the
RMECs. The lipid nature of these droplets was verified by oil red O staining. Results from this study demonstrate that RMECs
from immature virgin rats proliferate extensively and rapidly develop the capacity to synthesize and secrete casein and lipid
when grown within a reconstituted basement membrane under defined serum-free conditions. This unique system should thus serve
as an excellent model in which the regulation of mammary development and gene expression can be investigated.
This work was supported by grants CA 33240 and CA 35641 and by core grant CA 24538 from the National Institutes of Health,
Bethesda, MD. 相似文献
27.
Takashi Kamaishi Tetsuo Hashimoto Yoshihiro Nakamura Fuminori Nakamura Shigenori Murata Norihiro Okada Ken-ichi Okamoto Makoto Shimizu Masami Hasegawa 《Journal of molecular evolution》1996,42(2):257-263
Partial regions of the mRNA encoding a major part of translation elongation factor 1 (EF-1) from a mitochondrion-lacking protozoan,Glugea plecoglossi, that belongs to microsporidians, were amplified by polymerase chain reaction (PCR) and their primary structures were analyzed. The deduced amino acid sequence was highly divergent from typical EF-1's of eukaryotes, although it clearly showed a eukaryotic feature when aligned with homologs of the three primary kingdoms. Maximum likelihood (ML) analyses on the basis of six different stochastic models of amino acid substitutions and a maximum parsimony (MP) analysis consistently suggest that among eukaryotic species being analyzed,G. plecoglossi is likely to represent the earliest offshoot of eukaryotes. Microsporidians might be the extremely ancient eukaryotes which have diverged before an occurrence of mitochondrial symbiosis.
Sequence availability: The nucleotide sequence data reported here appear in the GSDB, DDBJ, EMBL, and NCBI databases with the accession number D32139 相似文献
28.
Strength of translation initiation signal sequence of mRNA as studied by quantification method: effect of nucleotide substitutions upon translation efficiency in rat preproinsulin mRNA. 总被引:2,自引:1,他引:1 下载免费PDF全文
Concerning the translation initiation signals in vertebrate mRNAs, both the ATG initiation codon and the sequences flanking the initiation codon are required to direct the position of initiation. A consensus sequence for the signal, (GCC)GCC(A or G)CCATGG, has been proposed, but actual initiation sequences differ from it to a greater or lesser degree. In the present report, the translation initiation signal sequences of rat preproinsulin and its mutant mRNAs were analyzed using a quantification method proposed previously. In this method, each 16 nt sequence in the mRNA was characterized by its sample score, which shows strength of the signal. So far, Kozak has constructed a number of preproinsulin mutant mRNAs in which nucleotides flanking the ATG codon are systematically varied, and measured the translation initiation efficiency in terms of the proinsulin product. Her experimental results were well understood on the basis of the strength of the translation initiation signal sequence. 相似文献
29.
30.
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