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91.
Perin L. Donnini M. Diomede L. Romano M. Tacconi M. T. Luisetti M. Salmona M. 《Cytotechnology》1991,7(1):25-32
An expression vector for G-CSF, pASLB3-3, was constructed and introduced into Namalwa KJM-1 cells (Hosoi et al., 1988), and cells resistant to 100 nM of methotrexate (MTX) were obtained. Among them, the highest producer, clone SC57, was selected and the productivity of this clone was further characterized. The maximal production of G-CSF was at the most 1.8 g/ml/day using a 25 cm2 tissue culture flask, even though the cell number was above 7×105 cells/ml. The limiting factors at high density were analyzed as the deficiency of nutrients, such as glucose, cysteine and serine, and pH control. The depression of specific G-CSF productivity per cell under the batch culture conditions was overcome by using a perfusion culture system, BiofermenterTM (Sato, 1983) with modifications of nutrients supplementation by a dialysis membrane and/or dissolved oxygen (DO) supplementation by microsilicone fibers. ITPSGF medium was modified to elevate concentrations of amino acids and glucose by 2.0- and 2.5-times, respectively. Under the control of pH at 7.4 and DO at 3 ppm, the specific G-CSF productivity was not depressed even at high cell density (above 1×107 cells/ml), and the amount of G-CSF reached 41 g/ml. These results indicated the possibility of finding the optimum culture conditions for the production of recombinant proteins by Namalwa KJM-1 cells.Abbreviations ABTS
2,2-Azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid
- BSA
Bovine Serum Albumin
- BSA-PBS
Phosphate-buffered Saline without Ca2+ and Mg2+ containing Bovine Serum Albumin
- dhfr
Dihydrofolate Reductase
- DO
Dissolved Oxygen
- G-CSF
Granulocyte Colony-stimulating Factor
- HEPES
4-(2-Hydroxyethyl)-1-piperazineethansulfonic Acid
- IFN
Interferon
- MTX
Methotrexate
- PBS(-)
Phosphate-buffered saline without Ca2+ and Mg2+
- Tween-PBS
Phosphate-buffered saline without Ca2+ and Mg2+ containing 0.05% of Tween 20 相似文献
92.
Summary The use of Cytophaga lysing enzymes was investigated for the liberation of poly--hydroxybutyrate (PHB) granules from the Gram-negative bacterium Alcaligenes eutrophus. Complete cell lysis was approached within a 60 minute period. Contrary to previous findings for the lysis of Gram-negative bacteria, prior removal of the outer membrane was not essential for enzymic lysis. The destabilisation of the outer membrane by the removal of divalent cations resulted in no significant improvement in the disruption process. 相似文献
93.
When male eastern bluebirds (Sialia sialis) are killed or deserttheir mates, replacement males usually take over the territory.We captured 25 eastern bluebird males and held them in captivityto study the behavior of replacement males and their responseto young already present in the nest. Of 17 replacement males,most courted the females, and 23% of experimental females renested,a proportion not different from that of control females. Noreplacement males were infanticidal, and none fully adoptedthe young. Replacement males spent significantly less time onthe territory and defended it significantly less than controlmales. We discuss breeding options available to a floater maleeastern bluebird and conclude that (1) floater male bluebirdsthat fill territory vacancies benefit by gaining breeding opportunitiesin the current breeding season, and (2) indifference to theyoung is the least costly option for replacement male easternbluebirds. 相似文献
94.
David I. Dunstan Debbie P. Lashta Susan I. Kikcio Trevor A. Thorpe 《In vitro cellular & developmental biology. Plant》1992,28(1):33-38
Summary The effects of sucrose concentration, addition of ammonium nitrate, and exposure to N6-benzyl-adenine (BA) on multiplication potential with shoots derived from shoot cultures of 17- to 20-yr-old Douglas fir trees
[Pseudotsuga menziesii (Mirb.) Franco] were compared. Each of these conditions, when compared independently, affected recurrent shoot multiplication
and influenced shoot development, as measured by the abundance of shoot apices. Sucrose concentration was influential, the
use of 25 g · liter−1 providing twice the multiplication obtained with 20 g · liter−1, and 14 × that obtained with the 30 g · liter−1 concentration routinely used (tree 11). Ammonium nitrate usage also improved multiplication, a 2.5 times improvement being
obtained after incorporation of 100 mg · liter−1 NH4NO3 into the medium (tree 33). Shoot cultures were responsive but relatively sensitive to addition of BA, the best improvement
in multiplication (5 times) being obtained with brief exposures to 3 mg · liter−1 BA (tree 11). Although shoot cultures were responsive to the conditions investigated, differences in shoot multiplication
and development were not displayed for several weeks. It was not possible therefore to repeat all the treatments with more
than one genotype; however, when this was possible a genotype-dependent variation in response was evident. 相似文献
95.
A. Henry Latorella Susan K. Bromberg Kent Lieber James Robinson 《Journal of phycology》1981,17(2):211-214
Fifteen nitrate assimilation-deficient mutants of the euryhaline green alga, Dunaliella tertiolecta Butcher were selected by their chlorate resistance. Ten mutants, unable to grow on NO3? but able to grow on NO2?, had no detectable nitrate reductase activity. Five mutants, unable to grow on either NO3? or NO2?, had depressed levels of both nitrate and nitrite reductase. A method for assaying methyl viologen-nitrate reductase in the presence of nitrite reductase is described. 相似文献
96.
97.
98.
Summary Orcein has been recommended for identification of elastin. Since other traditional elastica stains proved to be unspecific, it was deemed of interest to determine the selectivity of orcein and to review pertinent literature.Orcein was employed as a textile dye in ancient Egypt and was used for dyeing of wool and silk until the early 20th century. It was introduced into histological technic in 1878 as a stain for cytoplasm. Unna recommended it for demonstration of elastic tissue in 1890 and retracted claims for its specifity in 1894 because orcein colored also certain collagen fibers. Unna suggested the term collastin for collagen fibers which share the affinity of elastin for acid orcein. Other orcein solutions were used as selective stains for collagen.In histochemical studies, the staining properties of resorcin-fuchsin and orcein were very similar; elastin and various collagen fibers were strongly colored. Unna's collastin is apparently identical with the pseudo-elastica described in sections stained with resorcin-fuchsin. Both dyes react with meshworks of fine fibers, embryonic, experimentally or pathologically altered collagens. It is suggested to use the term collastin, instead of pseudo-elastica, for collagenous fibers which bind the traditional elastica stains. 相似文献
99.
Leaf pocket resins of 11 species of the tropical arborescent genus Hymenaea are virtually identical qualitatively, but of widely varying quantitative proportions. Within this large range of variability, several strong positive quantitative correlations between resin constituents were found, especially between caryophyllene and β-humulene and between γ-muurolene and δ-cadinene. These data lead to clarification of sesquiterpene biosynthetic routes in Hymenaea. In addition, quantitative relationships found among caryophyllene, α- and β-selinene, γ-muurolene and δ-cadinene are explained only with difficulty by long accepted biosynthetic pathways, and the intermediacy of germacrenes is suggested. 相似文献
100.
P. M. Bolton C. Teasdale A. M. Mander Susan L. James Joyce M. Davidson R. H. Whitehead R. G. Newcombe L. E. Hughes 《Cancer immunology, immunotherapy : CII》1976,1(4):251-258
Summary The immune competence of a group of 276 patients with suspected breast cancer has been assessed using a spectrum of tests: the peripheral lymphocyte count, serum immunoglobulin levels, lymphocyte response to phytohemagglutinin (PHA), Mantoux test, and dinitrochlorobenzene (DNCB) skin test. All tests were completed prior to any form of treatment as the initial part of an ongoing, long-term assessment which will ultimately relate immune competence to prognosis. 225 patients with breast cancer were allocated into stages based on their TNM status. The remaining 51 patients proved to have benign breast disease and made up the control group. In analysis, control patients were compared with early breast cancer patients, while the effect of advancing disease was assessed by betweenstage comparisons in the cancer group.There were no significant differences between early breast cancer and control patients or between cancer stages in peripheral lymphocyte count, serum immunoglobulin levels, lymphocyte response to PHA, or Mantoux responses. Age was found to have a crucial effect on some of these parameters and some apparent differences between the various groups lost significance after appropriate allowances were made for age.Important differences seen with the DNCB test persisted after allowing for age effects. Responses to DNCB were significantly depressed in patients with early breast cancer compared to controls. Patients with disseminated cancer showed greater depression than early breast cancer patients, but surprisingly, patients with locally advanced tumors had good responses to DNCB. Possible reasons for the paradoxical preservation of DNCB reactivity in patients with locally advanced cancer are discussed.The DNCB test is the most discriminating of the five tests of immune function studied. 相似文献