摘要:

AbstractThe initial inoculum level of Tetrahymena in a chemically defined medium determines whether the cells are capable of exponential growth. Below 750 cells ml−1, the cells fail to go into exponential growth and will die within about 20 hours. By adding certain growth stimulants, death can be postponed and the cells begin to grow after a delay which depends on the intensity of the signal. The implication is that autocrine growth factor expression might be required for cells to grow, and that these stimulants either assist its production or lower the cell threshold to its action. The findings in Tetrahymena are reviewed, and the advantages of having a cell system in which all the components of the medium can be carefully controlled is recognise

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1143

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractEM study of cultured human skeletal muscle explants on 10 consecutive days after incubation made possible a record for the first time, the early events occurring during regeneration. After incubation, normal myonuclei underwent activation and dense granulation. Some myonuclei showed early transformation to presumptive myoblasts. The conclusion was that myonuclei transformed into myoblasts which developed into satellite cells (SC). These SC of myonuclear origin, proliferated, and fused forming myotubes that matured into myofibres, replacing damaged muscle. The findings have new implications for the current myoblast / cell transplant and gene transfer therapy research which may provide possible answers for muscular dystrophy in the future.

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1144

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe presence of 10−6M bovine insulin in chemically defined nutrient medium prevented cell death and improved cell proliferation of the ciliate Tetrahymena pyriformis when inoculated at low initial cell density. The action of insulin was found to be restricted to the 22‐30 fragment of the B‐chain. These results suggest that small peptides are involved in regulation of cell survival and cell proliferation in Tetrahymena pyrif

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1145

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe synthesis of proteins from salt‐tolerant Brassica oleracea L. var. botrytis L. subvar. cauliflora (Gars.) DC. (cauliflower) cell cultures is modified in relation to controls in several features. There are nine newly induced polypeptides in tolerant cultures (absent in control conditions). Some of them are only present under low salt levels (85 mM NaCl). Another group seems to be representative of moderate and high salt levels (170 and 255 mM NaCl), and a third group is present in all the salt conditions tested. On the other hand, the synthesis of most of the polypeptides present in control conditions is modified in salt‐tolerant cultures by increasing, decreasing or stopping their synthesis in any of the tested conditions. The relationship between these changes in Brassica and other plant systems is discus

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1146

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractMPM‐2 antibody reacts with a subset of mitotic phosphoproteins. We followed localization of MPM‐2 immunoreactive material and localization of microtubules during cell cycle progression in a highly synchronous population of Vicia faba root meristem cells and isolated nuclei. The MPM‐2 antibody labelling showed significant cell cycle dependence. MPM‐2 nuclear reactivity was weak and homogeneous in G1 and S phase of the cell cycle and became stronger and heterogeneous during G2, resembling staining of the nuclear matrix, with maximum staining at the G2/M interface. Similarly the staining intensity of nucleoli increased from late G1 phase to nucleoli dispersion in early prophase. During mitosis MPM‐2 immunoreactivity was associated with spindle configurations and the brightest signal was localized in kinetochores from prophase to

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1147

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstractgas‐1 belongs to a family of growth arrest specific genes negatively regulated after growth induction of arrested cells. We report the expression of gas‐1 in an in vivo system of cell proliferation. gas‐1 mRNA accumulates progressively in the uterus of ovariectomized rats with a peak at three weeks after surgery. After estrogen treatment gas‐1 mRNA levels decrease within two hours, at a time when c‐myc expression is greatly increased, and return to pretreatment levels at 48 hours. Treatment with cycloheximide does not prevent estrogen‐induced down‐regulation of gas‐1 mRNA levels. The present results show that: i) estrogen affects the uterine growth state by regulating the expression of both positively and negatively acting genes, ii) gas‐1 expression is controlled by cellular growth s

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1148

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe culture medium of human arterial smooth muscle cells exhibits an elastinolytic activity with 68 and 64 kDa on elastin substrate gels. The enzymatic activities are inhibited by ethylenediamine tetraacetic acid, a metalloproteinase inhibitor, but not by other inhibitors of serine, cysteine and aspartic proteinases. The proteinase in the culture medium is activatable by 4‐aminophenylmercuric acetate and degrades insoluble elastin. Compared to other matrix metalloproteinases (MMP), the activity shows the similar elastinolytic pattern to that by MMP‐2 purified from human rheumatoid synovium, while MMP‐3 and MMP‐9 have different lytic patterns and MMP‐1 possesses no elastinolytic activity. An immunoblot analysis demonstrated that the 68‐kDa enzyme is MMP‐2. An immunofluorescence study illustrates that MMP‐2 is localized within the cytoplasm of the smooth muscle cells. These findings suggest that the elastinolytic enzyme secreted by human arterial smooth muscle

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1149

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA syngeneic, immunocompetent rat mammary model has been employed to investigate the molecular basis of the metastatic phenotype. Transfection of the benign rat mammary epithelial cell line Rama 37 with the gene for p9Ka; a small, rat, calcium‐binding protein or DNA from metastatic human cell lines derived from a primary breast carcinoma or a pleural effusion yields transfectants with metastatic capabilities. Transfection of DNA from a benign human mammary cell line, a plasmid containing a cDNA for the human basic fibroblast growth factor (bFGF) gene, or the oncogene EJ‐ras‐1, fails to yield any transfectants expressing the metastatic phen

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1150

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1151

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA protein‐free chemically defined medium designated PFEK‐1 was developed for culture of VERO cells on polyvinyl formal (PVF) culture surface without serum or other macromolecular supplements. VERO cells proliferated in PFEK‐1 medium on PVF surface to a similar extent as cells in serum‐supplemented medium without previous adaptation from serum‐containing conditions. The protein‐free culture infected with coxsackievirus B4, herpes simplex virus types 1 and 2, measles virus and poliovirus types 1, 2 and 3 developed viral titers comparable to those found in conventionally grown cells. The results demonstrated that VERO cells in protein‐free culture provide a sensitive substrate for the production of human pathogenic viruses which are not contaminated by serum or other protein factors usually added to a c

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1152

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY