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11.
Evidence from morphology and anatomy (including embryology), as well as from palynology, chemistry and cytology, indicates
thatHydrastis is quite divergent from Ranunculaceae (in which the genus has been most often included) as well as from both Glaucidiaceae
and Berberidaceae. Distinctive features ofHydrastis, which demarcate it from Ranunculaceae but which are sometimes shared by Berberidaceae, are: the unique mode of origin of
the vascular supply to stamens and carpels; the micropyle being formed by both integuments; the xylem not V-shaped in cross
section; scalariform vessel perforations present; haploid chromosome number 13; pollen tectum consisting of a compound layer
of striae; leaf mesophyll not differentiated; the unique course of stem medullary bundles; D-galactose present. Its distinctive
higher haploid chromosome number, as well as its many less-specialized character states (in floral structure, leaf anatomy,
and xylem and vessel morphology), suggest thatHydrastis is a relictual primitive group which diverged early from a common ancestral stock of Ranunculaceae, Berberidaceae and probably
of Circaeasteraceae; at least some of the features shared byHydrastis and one or another of the families concerned seem to be a heritage from their common ancestor. We propose a reestablishment
of a monotypic family, Hydrastidaceae. 相似文献
12.
Rabbit factor H, a control protein of the alternative complement pathway, was isolated from rabbit serum by polyethylene glycol precipitation, DEAE-Sephacel chromatography, and gel chromatography on Sephadex G200. The protein migrated as a single-chain polypeptide with a molecular weight of 160,000 on sodium dodecyl sulfate-gel electrophoresis with Laemmli's buffer system, but hardly migrated into the gel with Fairbanks' buffer system. Physical and chemical properties of rabbit H were similar to those of human H, except that fragments produced by limited tryptic digestion from rabbit H had different molecular sizes from those produced from human H. Significant species-specificity was observed in the functional activity of factor H; activation of the alternative complement pathway was inhibited more efficiently with homologous H than with heterologous H. In contrast, factor H inhibited the hemolysis of homologous erythrocytes less than that of heterologous erythrocytes. 相似文献
13.
Isolation and physical mapping of temperature-sensitive mutants defective in heat-shock induction of proteins in Escherichia coli 总被引:25,自引:0,他引:25
Summary Mutants of Escherichia coli K12 that are partially or totally defective in induction of major heat-shock proteins and cannot grow at high temperature (42° C) were isolated by localized mutagenesis. These mutants carry a single mutation in the gene htpR (formerly hin) located at min 76 on the E. coli genetic map. Some mutants exhibit delayed (partial) induction of heat-shock proteins or require a higher temperature for induction than the wild type, whereas others are not induced under any of these conditions. The maximum temperature that allows growth varies among different mutants and is correlated with the residual induction capacity. Temperature-resistant revertants obtained from each mutant are fully or partially recovered in heat-shock induction. These results indicate that the inability of htpR mutants to grow at high temperature is due to the defect in heat-shock induction. In addition, a couple of mutants was found that produce significantly higher amounts of heat-shock proteins even at 30° C.The htpR gene has been cloned into plasmid pBR322 using the above mutants, and was localized to a DNA segment of 1.6 kilobase pairs. The mutants harboring certain palsmids that carry a part of htpR produce temperature-resistant recombinants at high frequency. This permits further localization of mutations within the htpR gene. Analysis of proteins encoded by each of the recombinant plasmids including the one carrying a previously isolated amber mutation (htpR165) led to the identification of a protein with an apparent molecular weight of about 36,000 daltons as the htpR gene product. 相似文献
14.
Barbara Stay Lynda S. Ostedgaard Stephen S. Tobe Alain Strambi Eugene Spaziani 《Journal of insect physiology》1984,30(8):643-651
The free (non-conjugated) ecdysteroid in the ovaries during the first gonadotrophic cycle of Diploptera punctata was identified as 20-hydroxyecdysone. The hormone, quantified by radioimmunoassay and by ultraviolet absorbance, was detectable in the ovary toward the end of vitellogenesis; the quantity increased rapidly during chorion formation. Ovaries with chorionated eggs contained 67 μg of 20-hydroxyecdysone per g fresh weight. The haemolymph free-ecdysteroid, not identified physicochemically, was quantified by radioimmunoassays. The highest concentration was observed at adult emergence; the titre declined between days 1–3 and then remained at a relatively constant level through oviposition (which occurs between day 7 and 8); titres in pregnant females were higher. Ovariectomized females exhibited the same pattern of ecdysteroid titres in the haemolymph as the sham operated controls throughout the period corresponding to the first gonadotrophic cycle. Thus the ovary may not be the only source of haemolymph ecdysteroid related to reproduction in adult females. 相似文献
15.
In an effort to obtain orange mutants ofBlastocladiella emersonii
Cantino &Hyatt, wild type zoospores were treated with mitomycin. From the variants produced, we obtained a stable, albino mutant (Ma-1) that differs significantly from another, previously described (Shaw &Cantino, 1969) UV-induced, albino variant. This report concerns the origin of Ma-1, its distinguishing features, and its apparent similarity to the few LC (late colorless) plants that normally appear in wild type populations. A preliminary note regarding mitomycin-induced variants ofB. emersonii has been published (Matsumae &Cantino, 1970). 相似文献
16.
17.
Norimichi Kan Takashi Okino Masaki Nakanishi Kohei Satoh Kazuhisa Ohgaki Takayoshi Tobe 《Cancer immunology, immunotherapy : CII》1989,28(4):260-266
Summary The synergistic antitumor effect of interleukin-2(IL-2)-cultured tumor-bearer spleen cells (cultured lymphocytes) and immune fresh spleen cells was examined. Tumor-bearer cultured lymphocytes were obtained by culturing BALB/c spleen cells from syngeneic MOPC104E-tumor-bearing mice for 11 days with crude IL-2 and a soluble tumor extract. These cultured lymphocytes had weak antitumor activity when transferred i.p. into tumor-bearing mice that had been inoculated i.p. with 105 tumor cells 5 days previously. Immune fresh spleen cells, obtained from mice in complete remission after the treatment with cyclophosphamide, also had weak antitumor activity when transferred at the same schedule. The cultured cells and the fresh cells, mixed together before transfer, significantly augmented the therapeutic effect. At least 1×107 tumor-bearer cultured lymphocytes and 4×107 immune cells were needed for the synergistic effect. A tumor-specific combination was needed for both cultured and fresh cells. The effective subpopulation of tumor-bearer cultured lymphocytes was a cytotoxic one from an Lyt2+ precursor, and that of the immune fresh spleen cells was noncytotoxic, Lytl+ and Lyt2+ T-cells.A similar synergistic effect was also observed during in vitro coculture of tumor-bearer and immune cells. Cytotoxicity, as assessed by the 51Cr-release test, of tumor-bearer IL-2-cultured lymphocytes was maintained most effectively after 3 or 4 days of culture without IL-2 when the lymphocytes were cocultured with immune fresh spleen cells and tumor cells. 相似文献
18.
Oxygen-derived free radicals have been implicated as mediators of cellular injury in several model systems. In order to clarify the role of oxygen radicals in endotoxemia, we measured the serial lipid peroxide changes resulting from systemic radical reactions using a newly developed colormetric method. To determine the effect of a free radical scavenger on mortality in endotoxemia, a new synthetic scavenger, 2-Octadecylascorbic acid (CV-3611), which overcome the detrimental properties (circulation half-life and cell penetration) of native SOD, was used in the model of mouse endotoxemia induced by the i.p. administration of E-coli endotoxin (10 mg/kg). Serial LPO (Lipid Peroxide) changes revealed significant elevations from the basal level of 4.52 +/- 0.79 nmol/ml to 10.5 +/- 2.04 nmol/ml at 2h (P less than 0.05), 12.0 +/- 2.44 nmol/ml at 8h (P less than 0.05), 32.8 +/- 12.5 nmol/ml at 12h (P less than 0.05) and 13.6 +/- 2.40 nmol/ml at 24h (P less than 0.05) following i.p. administration of E-coli. The circulation half life of CV-3611 was checked by a reversed-phase HPLC after 10 mg/kg s.c. administration. The level of CV-3611 reached peak levels of 0.54 +/- 0.10 micrograms/ml at 1h and 0.52 +/- 0.20 micrograms/ml at 2h then gradually decreased to the level of 0.04 +/- 0.004 micrograms/ml at 6h and to a non-detectable level at 24h after s.c. administration. Increased survival was seen at 2 days (P less than 0.001) after E-coli endotoxin administration in the CV-3611 treated group compared to the control group. These results suggest that oxygen derived free radicals contribute to mortality in mouse endotoxemia and that antioxidants such as CV-3611 may provide a new therapeutic avenue by improving survival of patients with gram-negative bacterial sepsis. 相似文献
19.
Akihiro Ohira Eugene de Juan Jr Yasuo Tano Charles A. Wilson 《The Histochemical journal》1996,28(9):607-611
Summary It has been proposed that basic fibroblast growth factor (basic FGF) mediates the neovascular response in a variety of conditions,
including diabetic retinopathy and branch retinal vein occlusion. To test the hypothesis that basic FGF was released from
retinal stores as a result of retinal ischaemia, transient retinal ischaemia was induced, followed by 48 h of reperfusion,
in the rat by combined central retinal vasculature and optic nerve ligation. The immunolocalization of basic FGF was studied
in the retina. We found that basic FGF in the normal retina is present around the deeper retinal vessels and in the neuronal
tissue of the outer plexiform layer. In the eyes that had ischaemia followed by reperfusion, there was moderate cellular oedema
with retinal swelling, and mitoses in the inner nuclear and plexiform layers. There were no changes evident at the immunohistochemical
level either in the intensity or distribution of stores of basic FGF. We conclude from these data that stores of basic FGF
are not altered dramatically under the conditions of transient experimental ischaemia and reperfusion in the rat, despite
the presence of cellular proliferation. 相似文献
20.