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91.
92.
Effects of feeder layers made of human,mouse, hamster,and rat cells on the cloning efficiency of transformed human cells 总被引:1,自引:0,他引:1
Masayoshi Namba Fujiko Fukushima Tetsuo Kimoto 《In vitro cellular & developmental biology. Plant》1982,18(5):469-475
Summary The effect of feeder layers on cloning efficiency of transformed human cells was investigated. Embryonic human skin or lung
fibroblasts; adult human skin fibroblasts; early passage cells from embryos of mouse, rat, and hamster; established mouse
cell lines; 3T3 and 10T1/2 were used as feeder layers after they were lethally exposed to Co-60 gamma-rays at 3,000 rad. As
test cells to study the effect of feeder layers on cloning efficiency, WI-38 CT-1 cells transformed in vitro by Co-60 gamma-rays
and HGC cells cultured from a human gastric cancer were used. The effect of feeder layers on the cloning efficiency of the
test cells was dependent on cell density of feeder layer cells, sources of the feeder layer cells, and kinds of test cells.
An optimal density of feeder cels produced cloning efficiencies 3 to 15 times higher than in cultures without a feeder layer.
Generally, high density of cells in feeder layers decreased the cloning efficiency of the test cells, presumably owing to
contact inhibition of growth and depletion of essential nutrients by the feeder layer cells. Regarding the effect of the feeder
layers made of human fibroblasts, there were no significant differences in population doubling levels; tissue origins of fibroblasts;
or fibroblasts derived from normal individuals, patients with cancer, or with a genetically high familial incidence of cancer,
hereditary adenomatosis of the colon and rectum.
This study was supported by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture, Japan. 相似文献
93.
Summary Enzyme-deficient cell lines, lacking TK or HPRT and therefore unable to grow in HAT medium, may be used as feeder layers to
enhance clonal growth of wild-type cells. Low numbers of wild-type test cells may be plated in HAT medium with 5×105 HAT-sensitive feeder cells per Petri dish. The feeder cells remain attached and metabolizing for 1 to 2 weeks, but ultimately
die and detach, leaving colonies of test cells. This feeder layer technique is very simple and flexible and could have wide
applicability.
This work was a byproduct of a project on fusion and hybridization of marsupial and eutherian cells supported by the Australian
Research Grants Committee. 相似文献
94.
Peter C. Andersen Brent V. Brodbeck Russell F. Mizell III 《Entomologia Experimentalis et Applicata》1989,50(2):149-159
The efficiency of amino acid, organic acid and sugar metabolism was quantified for adult Homalodisca coagulata (Say) (Homoptera: Cicadellidae) by comparing chemical profiles of xylem fluid (food source) and insect exudate. Leafhoppers were confined in Parafilm® sachets to stems of 4 host plants: [Baccharis halimifolia (L.), Lagerstroemia indica (L.), Prunus salicina (Lindl.), Prunus persica (L.), Batsch]. Insect feeding rates (0.09–0.27 ml h–1), exudate osmolarity (7.8–12.8 mM) and exudate composition (mainly inorganic entities) were characteristic of a xylem feeder. Total organic solute concentration in the xylem fluid of B. halimifolia, L. indica, P. salicina and P. persica was ca. 9.4, 13.8, 5.5 and 1.8 mM, respectively. Nineteen protein amino acids, 7 organic acids and 3 or 4 sugars were identifid in the xylem fluid. Total amino acids, organic acids and sugars were metabolized with ca. 99% efficiency. Glutamine, asparagine, arginine and citric, malic and succinic acids, the predominant organic compounds in the xylem fluid of all four plant species, were metabolized with greater than 99% efficiency. Cysteine (51%), methionine (74%) and oxalic acid (77%) were metabolized with the lowest efficiency. The primary nitrogenous waste was NH
inf4
sup+
; uric acid or urea were not detected. Nitrogen retention was generally less than 60% of dietary nitrogen. High feeding rates, ammonotelism and an extremely high metabolic efficiency of organic compounds permit H. coagulata to subsist on the dilute and skewed chemical profile of xylem fluid.
Résumé L'efficacité du métabolisme des amino-acides, des acides organiques et des sucres a été quantifiée chez des H. coagulata Say (Hom. Cicadellidae) adultes, en comparant la composition chimique de la sève du xylème et du miellat des insectes. Les cicadelles ont été maintenues dans des sachets de parafilm avec des tiges de 4 plantes hôtes: Baccharis halimifolia L., Lagerstroemia indica L., Prunus salicina Lindl. et Prunus persica Batsch. Le taux de consommation (0,09 à 0,27 ml hr–1), l'osmolarité du miellat (7,8 à 12,8 mM) et la composition du miellat (principalement des éléments inorganiques) sont caractéristiques des consommateurs de xylème. Les concentrations organiques totales en soluté de la sève du xylème étaient respectivement: 9,4; 13,8; 5,5; et 1,8 mM chez B. halimifolia, L. indica, P. salicina et P. persica. 19 amino acides protéiques, 7 acides organiques et 3 ou 4 sucres ont été identifiés dans la sève du xylème. Les acides aminés, les acides organiques et les sucres ont été métabolisés dans leur ensemble avec une efficacité de 99%. La glutamine, l'asparagine, l'arginine et les acides citrique, malique et succinique,-les principaux composés organiques de la sève du xylème de ces 4 plantes,-ont été métabolisés avec plus de 99% d'efficacité. La cystéine (51%), la méthionine (74%) et l'acide oxalique (77%) ont été métabolisés avec une plus faible efficacité. Le déchet azoté primarie était NH inf4 sup+ ; l'acide urique et lurée n'ont pas été décelés. La fixation d'azote a été généralement inférieure à 60% de l'azote consommé. Des taux de consommation élevés, l'ammonotélisme et une efficacité extrêmement élevée du métabolisme des composés organiques permettent à H. coagulata de survivre malgré la composition chimique biaisée et la dilution de la sève du xylème.相似文献
95.
This work describes the preparation of combi-CLEAs of pectinases using feather meal as novel proteic feeder. Initially, four solvents were tested as precipitant agents, and ethanol was chosen as the best solvent. Subsequently, a 23 factorial design was carried out to define the optimal conditions for combi-CLEAs preparation, which were set as 110 mM of glutaraldehyde, 0.66 mg protein mL−1 and 5 h of reaction time. Then, the effect of BSA or feather meal (FM) as proteic feeders was evaluated. Combi-CLEAs, combi-CLEAs-BSA and combi-CLEAs-FM were characterized and evaluated by their activity recovery, optimal pH and temperature, operational and thermal stabilities and e effectiveness on juice clarification. The addition of feather meal increased two-fold the activity recovery compared to BSA. The thermal stability was similar for all combi-CLEAs, providing stabilization factors of 1.12, 1.48 and 1.53, respectively, for the combi-CLEA, combi-CLEA-FM and combi-CLEA-BSA, compared to free enzyme. CLEAs presented turbidity reduction near to 50%, 2.5-fold than soluble enzyme. Feather meal was used for the first time as proteic feeder for CLEA preparations and appears to be a good, and low price, alternative. 相似文献
96.
A new Pliocene deposit with vegetal impressionswas discovered at Rasteau (near Vaison-la-Romaine, Vaucluse. The study of these impression and the sporopollinic analysis from many levels allows us to specify its stratigraphical position in the Pliocene of the Rhone valley. So, the above mentioned levels settled just before the Hautimagne deposit (Neogene zone MN 14 for the mammals). The macroflora and the microflora appear to be related with a temperate warm and wet climate. 相似文献
97.
Seasonal fluctuations in the dietary components of Rasbora daniconius inhabiting a perennial eutrophic pond have been studied on the basis of analyses of the gut contents over a period of one year from 1980 to 1981. Modified Points method was adopted for the quantitative estimation of the dietary items. Gut analysis revealed that the fish is predominantly an allochthonous feeder subsisting mainly on terrestrial Hymenoptera and Coleoptera. Flowers and seeds also formed part of the dietary composition of the fish. Allochthonous fauna were preferred at all the stages of the growth of the fish. Females have a greater preference for terrestrial Coleoptera and the males for Formicidae. The feeding intensities of three different length groups and both sexes were also ascertained. This revealed that June, July, October and November are the most intensive feeding periods of R. daniconius. Older and mature fishes were found to be more active feeders than juveniles. 相似文献
98.
Andrew O. Martinez Thomas H. Norwood John W. Prothero George M. Martin 《In vitro cellular & developmental biology. Plant》1978,14(12):996-1002
Summary The growth of primary clones and serial subclones of HeLa cells and of diploid human fibroblast-like cells were compared both
in the presence and absence of feeder layers; the latter had no significant effects upon the results. Clones and subclones
of both cell types displayed great heterogeneity in growth rates, typically with a bimodality of growth distributions. Serial
passages of clones selected on the basis of superior rates of proliferation showed attentuation of growth potentials; the
extent of such attentuations was much less in the case of HeLa cells, suggesting at least one possible basis for the differences
in long-term growth potential between these two classes of cell lines.
This research was supported by Grants AG 00257 and AG 00592 from NIH. Dr. Martinez was supported by Postdoctoral Fellowship
AG/HD 02765 from NIH. 相似文献
99.
100.
Induced pluripotent stem(iPS) cells can be derived from human somatic cells by cellular reprogramming.This technology provides a potential source of non-controversial therapeutic cells for tissue repair,drug discovery,and opportunities for studying the molecular basis of human disease.Normally,mouse embryonic fibroblasts(MEFs) are used as feeder layers in the initial derivation of iPS lines.The purpose of this study was to determine whether SNL fibroblasts can be used to support the growth of human iPS cell... 相似文献