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排序方式: 共有307条查询结果,搜索用时 15 毫秒
1.
2-(2-Pyridyl)ethyl group is a new type P-O protecting group for the synthesis of oligodeoxyribonucleotides by the phosphite triester method. This group is stable to alkali and acid conditions, and to be removed from internucleotidic bonds under mild conditions via two step procedures without any side reactions. Further we have found that bis(diisopropylamino)chlorophosphine is much more effective for the preparation of bis(diisopropylamino)alkoxyphosphines than various dichlorophosphines. 相似文献
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We have developed a high cell density and high product concentration culture system recycling high molecular weight components. The production of monoclonal antibodies in high concentration was performed by this culture system with mouse human hybridoma H2 and V6 cells in serum-free defined media.The concentration of IgG after 48 days culture of H2 cells in ITES-eRDF reached 2 mg/ml and the purity of IgG in culture fluid was 61%. In addition, high molecular weight components in serum-free media, such as transferrin or BSA, could be reduced to 5% of the original concentration. 相似文献
4.
Sequence and over-expression of subunits of adenosine triphosphate synthase in thermophilic bacterium PS3 总被引:8,自引:0,他引:8
S Ohta M Yohda M Ishizuka H Hirata T Hamamoto Y Otawara-Hamamoto K Matsuda Y Kagawa 《Biochimica et biophysica acta》1988,933(1):141-155
The primary structures of all the subunits of thermophilic ATP synthase were determined, and its alpha, beta and gamma subunits could be over-expressed in Escherichia coli, because these subunits were stable and reconstitutable. DNA of 7500 base pairs in length was found to contain a cluster of nine genes for subunits of ATP synthase. The order of their reading frames (size in base pairs) was: I(381): a(630): c(216): b(489): delta(537): alpha(1507): gamma(858): beta(1419): epsilon(396), I being a gene for a small hydrophobic, basic protein expressed in vitro. All the termini of TF0F1 subunits were confirmed by peptide sequencing. Large quantities of the overexpressed thermophilic alpha, beta and gamma subunits were prepared from the extract of E. coli, by a few purification steps. 相似文献
5.
Highly purified sarcolemmal membranes, prepared from fresh bovine heart left ventricle, were solubilized by n-octyl beta-D-glucopyranoside and reconstituted into proteoliposomes with soybean phospholipids by the detergent-dialysis method. Ca2+ flux into the proteoliposomes was determined using the fluorescent probe Quin2. A membrane potential (negative in the proteoliposome interior) that was created by K+ diffusion mediated by valinomycin accelerated the Ca2+ influx. The voltage-dependent Ca2+ influx was dependent on pretreatment of the sarcolemmal membranes with Bay K 8644 and was inhibited by various calcium antagonists including nicardipine (K0.5 = 4.5.10(-7) M), verapamil (K0.5 = 9.2.10(-9) M), diltiazem (K0.5 = 26.10(-8) M) and omega-conotoxin (K0.5 = 9.5.10(-9) M). 相似文献
6.
J Richards S Hamamoto S Smith D Pasco R Guzman S Nandi 《Experimental cell research》1983,147(1):95-109
End buds from 4- to 5-week-old rat mammary glands were isolated and cultured within a rat tail tendon collagen gel matrix. Media containing equine serum or porcine serum and cholera toxin promoted growth, but not the production of casein or thioesterase II, nor did they induce a state of differentiation as assessed by cell ultrastructure. Medium supplemented with only 5% porcine serum, insulin and cholera toxin did not support growth or differentiation. However, when prolactin, estradiol, progesterone and hydrocortisone were added to this medium, growth was stimulated greatly and a differentiated state was induced as assessed by the production of casein and thioesterase and by the appearance of a highly secretory ultrastructure. 相似文献
7.
H. Takamatsu K. Hamamoto K. Ishimura S. Yokoyama M. Tokashiki 《Applied microbiology and biotechnology》1996,45(4):454-457
A high-cell-density perfusion culture process, using a novel centrifuge, was developed. The centrifuge has spiral multiple settling zones to separate cells from culture medium. Because of the multiple zones, the separation area can be efficiently increased without enlarging the diameter of the centrifuge. The centrifuge used in this study had a separation capacity of 2600 ml culture medium min–1 at 100g of the centrifugal force. A new cell separation and withdrawal method was also developed. The cells separated in the centrifuge can be withdrawn easily from the centrifuge with no cell clogging by feeding a liquid carrier such as a perfluorocarbon into the centrifuge and pushing the cells out with the liquid carrier. By this culture process, monoclonal antibodies were produced with mouse-human hybridoma X87X at a cell density of about 8 × 106 cells ml–1 for 25 days. This centrifuge culture shows promise as a large-scale perfusion culture process. 相似文献
8.
Effect of temperature and growth phase on fatty acid composition of the psychrophilic Vibrio sp. strain no. 5710 总被引:2,自引:0,他引:2
Tetsuo Hamamoto Nobuhisa Takata Toshiaki Kudo Koki Horikoshi 《FEMS microbiology letters》1994,119(1-2):77-81
Abstract The cellular fatty acid composition of the psychrophilic Vibrio sp. strain No. 5710 isolated from a deep-sea sediment sample was analyzed. The presence of docosahexaenoic acid (22:6) was demonstrated as found previously in other deep-sea bacteria, and the relative amount of 22:6 decreased as the growth temperature increased. A temperature shift from 10°C to 0°C resulted in a relative increase of 22:6, and an opposite shift led to a decrease. In addition, hexadecanoic acid (16:0) was found to increase as the growth temperature increased. Therefore, it is suggested that the adaptation of 5710 to the growth temperature was carried out by the changes in the relative amounts of 22:6 and 16:0. When 5710 was grown at low temperature, it increased the relative amount of 22:6 presumably to maintain membrane fluidity at that temperature. In contrast, 5710 grown at high temperature probably maintained the membrane fluidity by increasing the amount of a saturated fatty acid, 16:0. Furthermore, observation of the fatty acid compositions at mid-exponential phase and early stationary phase revealed the proportions of several fatty acids, including a major fatty acid, 9- cis -hexadecenoic acid (16:1c, palmitoleic acid), were affected by the growth phase which may be due to the physiological difference between the growth phases. 相似文献
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An extra idic(15p)(q11) chromosome in Prader-Willi syndrome 总被引:4,自引:0,他引:4
Using a nonfluorescent AT-specific oligopeptide antibiotic, Distamycin A, on DAPI fluorescent banding of human chromosome (DA-DAPI) as described by Schweizer et al. (1978), we have detected an additional idic(15p) chromosome in a patient with typical Prader-Willi syndrome. On the basis of the evidence available in previous studies and of our own present results, we suspect that the fundamental genetic error in the syndrome is not caused by a chromosome aberration but by a gene aberration on chromosome 15. 相似文献