Hela

Amino-2 -deoxypurines. 2 -AmiQo-2 -deoxyadenosine (15) is a naturally occurring A[-nucleoside isolated from A.ctinomadura that shows antknycoplasmal activity (1,4). Adenosine is the direct precursor for its biosynthesis (30). 2 -Arnino-2 -deoxyguanosine (16), isolated from a strain of Enterobacter cloacae (1,4), shows the growth of HeLa S3 cells and Sarcoma 180 in vivo and has been tested for antibacterial activity. 

Bredinin, Neosidomycin, and SF-2140. Bredinin (62), isolated from the culture filtrates of Eupenicillium brefeldianum (1,4), inhibits the multiplication of L5178Y, HeLa S3, RK-13, mouse L-ceUs, and Chinese hamster cells. GMP can reverse the inhibition by (62), but (62) is not incorporated into the nucleic acids. The inhibition of nucleic acid synthesis and chromosomal damage in the S and G 2 phases that is caused by (62), is reversed by GMP. It blocks the conversion of IMP to XMP and XMP to GMP. In combination with GMP, (62) interferes with intracellular cAMP levels and thereby inhibits cell division. 

Figure 4. Percentage survival (dashed lines) vs. percentage cells undergoing intracellular freezing (solid lines) in three mammalian cells frozen at various rates to -20 °C (HeLa) or to -78 °C to -196 °C (ova and red blood cells (RBC)). (Modified from Leibo, 1977. Sources of data for individual curves are given there.)...

The human HS cycle can be considered broadly as a period which leads to the dramatic shift in activities of the transcriptional and translational machinery followed by eventual recovery and resumption of original activities preceding stress. Figure 1 depicts many of the key events in the HS cycle for a typical human cell line such as cervical carcinoma-derived HeLa cells. Most cells respond in an identical fashion, but some cell types that have distinctive HS responses. These differences are manifested by shifts in the relative concentrations of accumulated HS proteins and possibly in the pattern of posttranslational modifications. In all cases, however, the cellular stress response is heralded by induction of a specific transcription factor whose DNA binding activity facilitates increased expression of one or more of the stress-inducible genes. 

Abravaya, K., Phillips, B., Morimoto, R.I. (1991a). Attenuation of the heat shock response in HeLa cells is mediated by the release of bound heat shock transcription factor and is modulated by changes in growth and in heat shock temperatures. Genes and Dev. 5, 2117-2127. 

Goldenbetg, C.J., Luo, Y., Fenna, M., Baler, R., Weinmann, R., Voellmy, R. (1988). Purified human factor activates heat shock promoter in a HeLa cell free transcription system. J. Biol. Chem. 263, 19734-19739. 

Legagneux, V., Morange, M., Bensaude, O. (1990). Heat-shock and related stress enhance RNA polymerase II C-terminal-domain kinase activity in HeLa cell extracts. Eur. J. Biochemistry 193, 121-126. 

Sorger, P.K., Lewis, M.J., Pelham, H.B.R. (1987). Heat shock factor is regulated differently in yeast and HeLa cells. Nature 329, 81-84. 

Historically, the development of animal cell culture systems has been dependent upon the development of new types of tissue culture media. Mouse L cells and HeLa cells were developed using a balanced salt solution supplemented with blood plasma, an embryonic tissue extract, and/or serum. In 1955 Eagle developed a nutritionally defined medium, containing all of the essential amino acids, vitamins, cofactors, carbohydrates, salts, and small amounts of dialyzed serum (Table 1). He demonstrated that this minimal essential medium (MEM) supported the long-term growth of mouse L and HeLa ceils. Eagle s MEM was so well defined that the omission of a single essential nutrient eventually resulted in the death of these animal cells in culture. 

Hutchings, S.E. Sato, G.H. (1978). Growth and maintenance of HeLa cells in serum-free medium supplemented with hormones. Proc. Natl. Acad. Sci. USA 75.901-904. 

In order to assess the effect of the corn cob xylan on the cell viability and proliferation rate, xylan solutions at concentrations of 0.1, 0.25, 0.50, 0.75, and 1 mg/ml were placed in contact with human cervical adenocarcinoma cells (HeLa cells) for 24 and 72 h. Finally, the cell viability was determined by the MTT assay. It was observed that regardless of the xylan concentration, the samples tested did not affect the viability of HeLa cells after incubation for 24 h (Figure 13) (Unpublished data). 

Besides, the statistical analysis of the results obtained confirmed that the xylan samples did not present a significant effect on the cell viability and cell proliferation rate when in direct contact with HeLa cells at the concentrations used in this study and compared to the control. 

Fig. 13. Viability of HeLa cells after incubation for 24 and 72h with solutions of xylan at...

Schonfelder, M., Horsch, A. Schmid, H.-P. (1985). Heat shock increases the synthesis of the poly(A)-binding protein in HeLa cells. Proceedings of the National Academy of Sciences, USA, 82, 6884-8. 

The test system was considerably less sensitive to endosulfan when mouse ER, rather than human ER, was used to mediate (3-gal activity (Ramamoorthy et al. 1997). In similar assays, endosulfan at 10 jM had no effect on (3-gal activity in yeast Saccharomyces) transfected with either the human or rainbow trout ER (Andersen et al. 1999). In addition, no effect was observed on transcriptional activation of HeLa cells transfected with plasmids containing an estrogen receptor as a responsive element (Shelby et al. 1996). Endosulfan also did not induce transient reporter gene expression in MCF-7 human breast cancer cells at an incubation concentration of 2.5 pM (Andersen et al. 1999). Maximum endosulfan-induced ER-mediated luciferase reporter gene expression occurred in vitro in a T47D human breast adenocarcinoma cell line at approximately 10 pM, while 50% expression of luciferase occurred at about 5.9 pM the maximum expression was approximately 59% of the effect from exposure to 0.03 nM estradiol (0.00003 pM) (Legler et al. 1999). Luciferase expression from combined treatment with endosulfan and dieldrin was additive over concentrations ranging from 3 to 8 pM. 

Fig. 3. Comparison of transfection efficiencies obtained using PolyFect Reagent, a dendrimer-based transfection reagent, and a calcium phosphate-mediated procedure. COS-7 and HeLa cells were transfected in srx-weU plates with a /3-galactosidase expression plasmid using the appropriate protocol. For the calcium phosphate-mediated transfection, 6 pg of plasmid DNA was used and the medium was changed after 5 h incubation. Transfections were performed in triplicate, and transfection efficiency was measured by monitoring the /3-galactosidase activity of extracts obtained from the transfected cells. The amoimt of /3-galactosidase activity in the extracts correlates with the transfection efficiency. Cells were harvested 48 h post-trans-fection...

The generation number, activation procedure, and core moiety of PolyFect Transfection Reagent have been developed specifically for transfection of certain cell lines, including HeLa and COS-7. Optimized amounts of DNA and den-drimer delivered transfection efficiencies in both cell lines significantly higher than those obtained using a standard transfection method. 

Bootman M, NiggU E, Berridge M, Lipp P (1997) Imaging the hierarchical Ca signalling system in HeLa ceUs. J Physiol 499(Pt 2) 307-314... 

There are now available a number of lines of cells, mainly originating from malignant tissue, which can be serially subcultured apparently indefinitely. These established cell lines are particularly convenient as they eliminate the requirement for fresh animal tissue for such sets or series of cultures. An example of these continuous cell lines are the famous HeLa cells, which were originally isolated from a cervical carcinoma of a woman called Henrietta Lacks, long since dead but whose cells have been used in laboratories all over the world to grow viruses. 

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