Cellular oxygen measurement

The experimental set-up for cellular oxygen measurements (p02) consists of following components p02 measuring micro chamber (volume 0.6 microliter), polarographic microelectrode, water-bath for constant temperature, chemical microsensor connected to a strip-chart recorder and gas calibration unit. 

Once Kitt is known, the cellular oxygen consumption rate, qX, can be measured under culture conditions. The mass balance for oxygen in a batch reactor with cells is given by ... 

In practice, carbon limited chemostat cultures are used to estimate the P/O quotient These conditions are used because they favour the most efficient conversion of the carbon substrate into cellular material, ie the highest efficiency of energy conservation. The steady state respiration rate (qo,) is measured as a function of dilution rate (specific growth rate) and Yq can be obtained from the reciprocal of the slope of the plot. qo, is also known as the metabolic quotient for oxygen or the specific rate of oxygen consumption. 

Lucigenin is often used to facilitate the measurement of reactive oxygen species in immunological studies, because it enhances the cellular CL intensity [37], Both luminol and lucigenin can be used to measure reactive oxygen how-... 

Off-gas analysis is widely used in many industrial fermentation plants to determine the cellular activity of growing cultures by monitoring respiration. One can measure oxygen uptake and CO2 production rates and thus measure metabolic activity/9 In addition, off-gas analysis is also used for monitoring other volatiles, the synthesis of which are strongly dependent on cultivation conditions 10 and product formation. 11 Off-gas estimation and control therefore serves as an indirect method for process analysis and control. 

Respiration Studies in Isolated Mitochondria Cellular respiration can be studied in isolated mitochondria by measuring oxygen consumption under different conditions. If 0.01 m sodium malonate is added to actively respiring mitochondria that are using pyruvate as fuel source, respiration soon stops and a metabolic intermediate accumulates. 

The time scale of the oxygen effect is of particular interest as it yields information as to the lifetime of the free-radical lesions in a cellular environment. Several approaches to measure such lifetimes have been followed (Adams et al. 1976b Michael 1984 Adams 1985). 

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