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Abstract  

Microcalorimeters to monitor the heat dissipation of bench-scale animal cell cultures on line and in real time require a continuous circuit between the vessel measuring heat flow rate and the bioreactor. The modifications to the transmission lines and calorimetric heat exchanger were to: (i) reverse the usual upward direction of the cell suspension in the flow vessel to downwards; (ii) install an in situ washing/cleaning facility; (iii) use low diffusivity PEEK material; and (iv) maintain thermal equilibration by water-jacketing the transmission tubing. Chemical calibration showed that there was more than a 20% difference between the physical volume and the effective thermal volume. An appropriate thermodynamic system was defined in order to permit enthalpy balance studies.

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Abstract  

After a formal explanation of Mayer's enthalpy balance method as applied to biological reaction rates, the history of its application is traced from Rubner's dog to accounting for the energy of muscle contraction. The introduction of microcalorimetry allowed the method generally to be used for cells in vitro and now particular emphasis can be paid to the growth of cells for the production of therapeutically-important heterologous proteins. In these systems, enthalpy balance studies contribute to defining catabolic processes, designing media, understanding the mechanisms of growth and controlling cultures using heat flux as an on-line sensor of metabolic activity.

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The potential of crude extracts from four plant species were evaluated for their ability to control the Tetranychus cinnabarinus mites under controlled conditions. The extracts were prepared from four plant species Artemisia herba-alba, A. leucodes, Eruca sativa and Sinapis alba . The toxicity of the four plant extracts to animal cells was measured in vitro using the vital mitochondrial dye 3-[4,5-dimethyliazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The assay revealed that the extracts from A. herba-alba, A. leucodes or S. alba were not toxic to animal cells up to concentrations of 100 µg/ml. Extracts from E. sativa at concentrations > 100 µg/ml were found to significantly reduce cell viability and are therefore toxic to animal cells. The mortality and repellency potential of the different extracts showed that A. leucodes or E. sativa at a concentration of 50 µg/ml resulted in more than 80% mortality and repellency. However, extracts at the same concentration from A. herba-alba or S. alba caused only 58% and 71% mortality and repellency, respectively. These results indicate that further investigations are required to characterize and identify the bioactive ingredients from A. leucodes and E. sativa that revealed greater potential as acaricidal sources for mite control.

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Abstract  

To meet the need for studies of anaerobic microbial and animal cell cultures involving much lower heat effects as compared to aerobic microbial cultures, a bench scale calorimeter, Bio-RCl, has been improved for achieving a higher long-term sensitivity. This newly improved Bio-RCl was used for heat measurement of anaerobic growth of Lactobacillus helveticus. The results showed that the bench-scale calorimetry has powerful potential for on-line monitoring and control of anaerobic bioprocesses as well as fundamental studies, such as stoichiometry, thermodynamics and kinetics of cellular growth.

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The recent review summarizes the major achievements in discovery of role of phytoglobins in mediation of nitric oxide generated cellular functions in higher plants. Genes encoding non-symbiotic hemoglobins have been cloned from several plant species. The expression pattern of these genes show tissue-specificity that is also under the control of stress factors like hypoxia. The nitric oxide has pivotal role in signalling pathway specifically in hypersensitive reactions and programmed cell death. Production of transgenic tobacco plants overexpressing the alfalfa hemoglobin showed altered necrotic symptoms after treatment with nitric oxide generating compounds or infection by necrotic pathogens. The present review helps to outline the similar relation between hemoglobin and nitric oxide in plants as it was found in animal cells.

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Colchicine is a plant alkaloid, known for thousands of years and currently used widely for the doubling of the genome in plant and animal cells due to its antimitotic effect. The aim of the present experiments was to develop stable autodiploid pollen grains in vitro in diploid lines of rye (Secale cereale L.) and barley (Hordeum vulgare L.) and to use these in intra- and interspecific crosses. Spikelet cultures of one rye and one barley variety were subjected to colchicine treatment in different stages of development and under differing in vitro conditions. Exposure to colchicine led to a drastic reduction both in the number of fertile pollen grains and in the percentage seed-setting, which was only observed in cultures inoculated in the early binuclear microspore stage. On medium containing colchicine the seed-setting percentage was 1.6% for barley and 0.1% for rye. Flow cytometry and root tip analysis revealed that all the progeny barley plants were diploid, while in the case of rye one was tetraploid, indicating that the egg cell may also be diploidised by colchicine treatment.

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Reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx) are vital components of the antioxidative barrier in animal cells. It is suggested more often now that the effectiveness of the protection of cells against the oxidative stress caused by the inflammation process depends on the amount of GSH and the activity of SOD, CAT and GSHPx. That is why the effect of zymosan A (40 mg/kg body mass) and the combined treatment with zymosan A (at the same dose) and melatonin (50 mg/kg body mass) on the amount of GSH in the blood and the amount of GSH and activity of SOD, CAT and GSHPx in the brain, liver and kidneys of male mice was estimated. Animals (n = 108) were decapitated after 3, 6 and 24 hours since the moment of the administration of only zymosan A, and combined zymosan A and after one hour melatonin. After the injection of zymosan A it was found that the amount of GSH is significantly lower after 3 and 6 hours in the blood and studied organs. The administration of zymosan A, followed by the administration of melatonin limited the decrease in the amount of this tripeptide in the same time. Simultaneously, the decrease in the amount of GSH in the studied organs was accompanied by a similar decrease in the activity of SOD, CAT and GSHPx after the injection of only zymosan A and a limited decrease in the activity after the administration of both zymosan A and melatonin. It is suggested that a decreased content of GSH and a decrease in the activity of the studied antioxidative enzymes is caused by the oxidative stress accompanying the inflammation process.

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Freshney, R. I. (2000) Cell lines, Protocol 12.2. In: Freshney, R. I. (ed.) Culture of Animal Cells. A Manual of Basic Technique . Wiley-Liss Publication, New York, pp. 184–188. Freshney R. I

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Liebeskind, D., Bases, R., Elequin, F., Neubrot, S., Leifer, R., Goldberg, R. & Koenigsberg, M. (1979): Diagnostic ultrasound: effects on the DNA and growth patterns of animals cells. Radiology , 131 , 177

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311 Omaye, S.T., Turnbull, J.D., Sauberlich, H.E. (1979): Selected methods for the de-termination of ascorbic acid in animal cells, tissues and fluids. Methods in Enzymology 62, 3

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