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71.
Shinichi Kitamura Takashi Hirano Kenichi Takeo Mitsuru Mimura Kanji Kajiwara Bjrn T. Stokke Tsutomu Harada 《International journal of biological macromolecules》1994,16(6)
The conformation and dilute solution properties of (2→1)-β-d-fructan in aqueous solution were studied by gel permeation chromatography, low-angle laser light-scattering photometry, viscometry, small-angle X-ray scattering and electron microscopy. Fractions covering a broad range of weight-average molecular weights (Mw) from 1.49 × 104 to 5.29 × 106 were obtained from a native sample by ultrasonic degradation and fractional precipitation. For Mw < 4 × 104, the intrinsic viscosity [η] varies with Mw0.71, indicating that the fructan chain behaves as a random coil expanded by an excluded-volume effect in this molecular weight region. For Mw > 105, [η] exhibits an unusually weak dependence on Mw and finally becomes almost independent of molecular weight. This behaviour is interpreted in terms of a globular conformation of the high-molecular-weight fructan molecules. Small-angle X-ray-scattering measurements and electron microscopic observations support this interpretation of the values of [η] observed. 相似文献
72.
Summary A rapid, simple, and sensitive method for plasmid copy number comparison was developed. The extracted plasmids from the same
amount of cells were subjected to agarose gel electrophoresis and the gels photographed. The photographs were processed by
a Macintosh image analyser to enumerate the densities of plasmid bands. As a size reference, λ-DNA digested with a restriction
enzyme was used. The densities divided by size of plasmids (base pair) would represent relative values of their copy numbers. 相似文献
73.
Takeshi Tabira Jun-ichi Inobe Keiichi Nakahara Mitsuhiro Osame Takashi Yamamura 《Neurochemical research》1994,19(8):1067-1071
To understand the immune mechanism suggested in HTLV-I-associated myelopathy (HAM/TSP), we investigated T cell response to proteolipid protein (PLP). Because of high autologous proliferative response (APR) of peripheral blood mononuclear cells (PBMC) in culture, the lymphocyte proliferation assay was not useful in this disease. Unexpectedly, however, APR was profoundly (70–98%) suppressed in 6 of 9 cases when PLP peptide 105-124 was added in the culture. PLP peptide 85-104 or 145-159 also suppressed APR in a few cases. Time course study showed that the peptide-mediated suppression became apparent after day 4 in culture. The results can be interpreted as that suppressor cells recognizing the PLP peptides were present in the PBMC of HAM/TSP patients and suppressed the APR as the consequence of antigen specific response. This may indicate that a T cell response to certain PLP determinants is involved in the pathomechanism of HAM/TSP at least in part. Molecular mimicry between PLP and HTLV-I mayaccount for the T cell sensitization to PLP in HAM/TSP.Special issue dedicated to Dr. Marjorie B. Lees. 相似文献
74.
75.
The presence of an adenylate translocator in the envelope membranesof proplastids isolated from the cultured cells of tobacco (Nicotianatabacum L. cv. BY2) was examined by means of transport experimentsusing the silicone oil filtering centrifugation technique. Itwas observed that proplastids can import [3H]ATP, [3H]ADP, [3H]AMPand less specifically ADP-[14C]Glc which can eventually be usedfor starch biosynthesis. The effects of specific inhibitorsof the mitochondrial adenylate translocator, i.e. atractyloside,bongkrekic acid and carboxyatractyloside were tested. Similarto the case of amyloplasts isolated from the cultured cellsof sycamore and chloroplasts isolated from spinach leaves, onlyATP and ADP-Glc uptake were shown to be partially inhibitedby carboxyatractyloside. On the other hand, neither atractylosidenor bongkrekic acid exerted a significant inhibitory effecton adenylate uptake. (Received August 8, 1992; Accepted November 26, 1992) 相似文献
76.
Sakamoto Atsushi; Ohsuga Hiroyuki; Wakaura Makoto; Mitsukawa Norihiro; Hibino Takashi; Masumura Takehiro; Sasaki Yukiko; Tanaka Kunisuke 《Plant & cell physiology》1993,34(6):965-968
A cDNA clone for copper/zinc-superoxide dismutase (Cu/Zn-SOD)was isolated from spinach (Spinacia oleracea L.) leaves. Itsnucleotide sequence showed that it codes for a precursor polypeptideof 222 amino acids, including the NH2-terminal 68-residue extensionwhich corresponds to a plastidic transit peptide. Northern hybridization,using plastidic and cytosolic Cu/Zn-SOD cDNAs as the probes,revealed that these two genes are differentially expressed inthe roots and leaves of spinach.
1Present address: Department of Biochemistry and Microbiology,Cook College, Rutgers University New Brunswick, NJ 08903-0231,U.S.A. 相似文献
77.
Kazumi Yamada Takashi Yamamoto Koji Akasaka Hiraku Shimada 《Development, growth & differentiation》1993,35(6):703-710
Eight restriction fragments (I–VIII) were prepared to cover a whole span of the enhancer region in the upstream of the Ars gene of the sea urchin, Hemicentrotus pulcherrimus , and their abilities to influence on the Ars gene expression were estimated by CAT assay. Only three fragments (III, IV and V) encompassing a 0.6 kb region between −2.8 kb and −2.2 kb stimulated CAT expression. By mobility shift assays, it was found that the Ars enhancer region is composed of multiple cis -acting elements that interact with nuclear proteins in a sequence-specific manner. Among them, two sequences, a G-string and a GATCTCCCC, were determined by DNA footprinting as sites of protein-DNA interaction. The DNA-binding factor prevalence changed ontogenically in three different patterns. Possible activation of DNA-binding proteins through their modification is discussed. 相似文献
78.
Masato Maekawa Kayoko Sudo Masato Kitajima Yukio Matsuura Steven S.-L. Li Takashi Kanno 《Human genetics》1993,92(2):163-168
In northwest European countries maternal age is increasing. This will lead to an increase of the prevalence of Down syndrome conceptuses. Meanwhile, the increased use of prenatal cytogenetic diagnosis (PCD) will lead to a decrease in the prevalence of Down syndrome among livebirths. We were interested to know what the result of these two opposite developments would be in the near future, and we describe here a model to quantify these processes and the resulting livebirth prevalence of Down syndrome. The model is demonstrated for The Netherlands from 1992 to 2001. The predicted livebirth prevalence for The Netherlands in 1992 is 1.36 per 1000. Demographic factors will cause an increase to 1.76 per 1000 in 2001 with present indications for PCD and a utilization ratio of 50%. An increase of the utilization ratio to 90% in 2001 will lead to a prevalence of 1.22 per 1000, a little less than the present prevalence. Alternative screening programs, including maternal serum screening, could lead to a further decrease of the livebirth prevalence. The model described here can be used for evaluation of the consequences of alternative forms of Down syndrome screening. 相似文献
79.
Toshiyuki Takahashi Hiroshi Ishikura Kazuhiro Iwai Chisa Takahashi Hiroyuki Kato Tatsuzo Tanabe Takashi Yoshiki 《Cancer immunology, immunotherapy : CII》1993,36(2):76-82
The permanent pancreas carcinoma cell line, PCI-24, was developed in order to analyse cytokine regulation on pancreas carcinoma and lymphokine-activated killer (LAK) cell interaction. PCI cells expressed ICAM-1 and HLA-ABC, but not HLA-DR antigens. PCI cells showed augmented ICAM-1 and HLA-ABC expression when incubated with interferon (IFN) and tumour necrosis factor . A similar but weak augmentary effect on the HLA-ABC and ICAM-1 surface expression was seen with interleukin-1 treatment. Natural attachment of LAK to PCI cells was augmented by recombinant IFN in close association with ICAM-1 up-regulation on PCI cells. In addition, natural attachment was significantly inhibited by anti-LFA-1 and anti-ICAM-1 antibody treatments. Cytotoxicity of the LAK cells against PCI cells was also significantly inhibited with the same treatment. Thus, the attachment of LAK cells to PCI cells through LFA-1/ICAM-1 molecules appeared to be essential for the cytotoxicity for PCI cells. Pretreatment of PCI cells, but not of LAK cells, with IFN or other cytokines resulted in a decrease of susceptibility for LAK cell cytotoxicity. The decreased susceptibility inversely correlated with HLA-ABC expression on the PCI cells. The collective evidence indicates that, although LAK cell attachment to pancreas carcinoma cells through the LFA-1/ICAM-1 molecule is augmented by IFN, IFN treatment of pancreas carcinoma cells reduces LAK cell cytotoxicity possibly through an increase in HLA-ABC or a regulation of molecules closely associated to HLA-ABC expression. 相似文献
80.