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71.
Hee Wook Ryu Kyung Suk Cho Young Keun Chang Ho Nam Chang 《Biotechnology Techniques》1996,10(12):899-904
Summary
Alcaligenes eutrophus was successfully recovered from high cell density broths by pre-treatment with polyaluminium hydroxide chloride silicate as a coagulant at 36–90 mg Al/l. The optimum pH range for cell coagulation was 10–12. Subsequent centrifugation (45×g) and filtration (pore size 0.5 mm) gave a cell recovery of higher than 90%. The energy demand for cell recovery with the coagulant was only 3–11% of that without it. 相似文献
72.
Hongkui Jin Renhui Yang Gilbert A. Keller Anne Ryan Annie Ko David Finkle Todd A. Swanson WeiLi Diane Pennica William I. Wood Nicholas F. Paoni 《Cytokine》1996,8(12):920-926
Cardiotrophin-1 (CT-1) is a recently discovered cytokine that was isolated based on its ability to induce cardiac myocyte hypertrophy in vitro. In this study, the effects of chronic administration of CT-1 to mice (0.5 or 2 μg by intraperitoneal injection, twice a day for 14 days) were determined. A dose-dependent increase in both the heart weight and ventricular weight to body ratios was observed in the treated groups. The body weights of the animals were unaffected. These results indicate that CT-1 can induce cardiac hypertrophy in vivo. CT-1 was not specific for the heart, however. It stimulated the growth of the liver, kidney, and spleen, and caused atrophy of the thymus. CT-1 administration also increased the platelet counts by 70%, with no change in mean platelet volume. Red blood cell counts were increased in the treated animals, and there was a concomitant increase in haemoglobin concentration. Thus, CT-1 has a broad spectrum of biological activities in vivo. This observation is consistent with previous in-vitro findings showing that the mRNA for CT-1 is expressed in several tissues, and that CT-1 can function through binding to the leukaemia inhibitory factor (LIF) receptor and signalling through the gp130 pathway. 相似文献
73.
Hyun Koo Kim Moon Sun Ham Jong Soo Hong Jin Ha Lee Kyung Yu Park Hyeon Yong Lee 《Biotechnology and Bioprocess Engineering》1996,1(1):32-35
A moving aeration-membrane (MAM) bioreactor was employed for the production of 2 μg/mL of tissue type Plasminogen Activator (tPA) in serum free medium from normal human fibroblast cells. This system could maintain high cell density for long periods of steady state conditions in perfusion cultivation. Under normal operating conditions, shear stress was as low as 0.65 dynes/cm2 at the agitation speed of 80 rpm. Even though cell density gradually decreased with increasing agitation speed, tPA production increased linearly with increasing shear stress within a moderate range. This culture system allowed production of 2 μg tPA/mL while maintaining a high cell density of 1.0×107 viable cells/mL. 相似文献
74.
P. W. J. Taylor J. R. Geijskes H.-L. Ko T. A. Fraser R. J. Henry R. G. Birch 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,90(7-8):1169-1173
Random amplified polymorphic DNA (RAPD) analysis using 10-mer oligonucleotide primers efficiently differentiated sugarcane cultivars and proved suitable for detecting gross genetic change such as that which can occur in sugarcane subjected to prolonged tissue culture, for example in protoplast-derived callus. However, RAPD analysis was not sufficiently sensitive to detect smaller genetic changes that occur during sugarcane genetic transformation. The length of DNA scored for polymorphism per primer averaged 13.2 kb, or 0.0001% of the typical sugarcane genome size of 1.2 × 107 kb (2C). RAPD analysis of sugarcane plants regenerated from embryogenic callus revealed very few polymorphisms, indicating that gross genetic change is infrequent during this tissue culture procedure, although epigenetic effects result in transient morphological changes in regenerated plants. More sensitive variations on the RAPD technique may increase the practicality of DNA-based screening of regenerated plant lines to reveal somaclonal variants. 相似文献
75.
Microbial flocculant from Arcuadendron sp. TS-49 总被引:9,自引:0,他引:9
Summary A flocculant was purified from the culture broth of Archuadendron sp. TS-49 by a series of precipitations with acetone, 60% ammonium sulfate-butanol, salting-out by dialysis, and cetylpyridinium chloride. The flocculating activity was observed most highly at pH 3.0 and markedly enhanced by the addition of salts, especially in the case of FeCl3 or FeSO4. This bioflocculant efficiently flocculated all tested solids, including various microorganisms and organic/ inorganic materials. Qualitative analyses of the bioflocculant showed that it might contain hexosamine, uronic acid, neutral sugar, and protein. 相似文献
76.
Mixed-phase plants of Griffithsia japonica Okamura spontaneously occurred in a laboratory culture. Four female plants produced tetrasporangia and spermatangia in addition to their normal female reproductive structures (bisexual/mixed-phase plants), and four male plants produced tetrasporangia as well as spermatangia (male/mixed-phase plants). To determine the nuclear ploidy level of these mixed-phase plants, relative nuclear sizes of male, female, tetrasporangial, and mixed-phase plants were measured using a microscopic image analysis system. Haploid gametophytes could be distinguished from diploid tetrasporophytes by relative nuclear sizes, with the later having nuclei twice the size of the former. Relative nuclear sizes of the mixed-phase plants were similar to those of the haploid plants. Thus, the mixed-phase plants were determined to be haploid. Haploid mixed-phase plants of G. japonica have a potential to produce male, female and tetrasporangial reproductive structures. Sex determination models are discussed to explain "haploid" mixed-phase phenomena in red algae . 相似文献
77.
78.
Nanduri VB Hanson RL Laporte TL Ko RY Patel RN Szarka LJ 《Biotechnology and bioengineering》1995,48(5):547-550
10-Deacetylabaccatin III (10 DAB), an important precursor for paclitaxel semisynthesis, is enhanced in yew extracts using C10-deacetylase and C13-deacylase enzymes.(4) C10-deacetylase is an intracellular enzyme produced by the fermentation of a soil microorganism, Nocardioides luteus (SC 13912). During the fermentation of Nocardioides luteus, the growth of cells reaches a maximum growth at 28 h. C10-deacetylase enzyme activity starts at 26 h and peaks at 38 h of the fermentation. The cells are recovered by centrifugation. The C10-deacetylase enzyme was purified from the Nocardioides luteus cells. The enzyme was purified 190-fold to near homogeneity. The purified enzyme appeared as a single band on 12.5% SDS-PAGE analysis with a molecular weight of 40,000 daltons. (c) 1995 John Wiley & Sons, Inc. 相似文献
79.
80.
Identification of three genetic loci controlling leaf senescence in Arabidopsis thaliana 总被引:23,自引:3,他引:20
Sung Aeong Oh Joon-Hyun Park Gyu In Lee Kyung Hee Paek Soon Ki Park Hong Gil Nam 《The Plant journal : for cell and molecular biology》1997,12(3):527-535
Four mutants that show the delayed leaf senescence phenotype were isolated from Arabidopsis thaliana . Genetic analyses revealed that they are all monogenic recessive mutations and fall into three complementation groups, identifying three genetic loci controlling leaf senescence in Arabidopsis . Mutations in these loci cause delay in all senescence parameters examined, including chlorophyll content, photochemical efficiency of photosystem II, relative amount of the large subunit of Rubisco, and RNase and peroxidase activity. Delay of the senescence symptoms was observed during both age-dependent in planta senescence and dark-induced artificial senescence in all of the mutant plants. The results indicate that the three genes defined by the mutations are key genetic elements controlling functional leaf senescence and provide decisive genetic evidence that leaf senescence is a genetically programmed phenomenon controlled by several monogenic loci in Arabidopsis . The results further suggest that the three genes function at a common step of age-dependent and dark-induced senescence processes. It is further shown that one of the mutations is allelic to ein2-1 , an ethylene-insensitive mutation, confirming the role of ethylene signal transduction pathway in leaf senescence of Arabidopsis . 相似文献