Cell, growth stages

Karathanasis E, Wilson TE. Enhancement of Saccharomyces cere-visiae end-joining efficiency by cell growth stage but not by impairment of recombination. Genetics 2002 161 1015-1027. 

For type 3 processes, growth and metabolic activity reach a maximum early in the batch process cycle (Figure 3.1) and it is not until a later stage, when oxidative activity is low, that maximum desired product formation occurs. The stoichiometric descriptions for both type 3 and 4 processes depend upon the particular substrates and products involved. In the main, product formation in these processes is completely uncoupled from cell growth and dictated by kinetic regulation and activity of cells. 

Once there is an appreciable amount of cells and they are growing very rapidly, the cell number exponentially increases. The optical cell density of a culture can then be easily detected that phase is known as the exponential growth phase. The rate of cell synthesis sharply increases the linear increase is shown in the semi-log graph with a constant slope representing a constant rate of cell population. At this stage carbon sources are utilised and products are formed. Finally, rapid utilisation of substrate and accumulation of products may lead to stationary phase where the cell density remains constant. In this phase, cell may start to die as the cell growth rate balances the death rate. It is well known that the biocatalytic activities of the cell may gradually decrease as they age, and finally autolysis may take place. The dead cells and cell metabolites in the fermentation broth may create... 

Electron micrographs of freeze-etched preparations clearly demonstrated that S-layers completely cover the cell surface during all stages of cell growth and division [5,56,57]. 

Egawa T, Kawabata K, Kawamoto H, et al. The earliest stages of B cell development require a chemokine stromal cell-derived factor/pre-B cell growth-stimulating factor. Immunity 2001 15 323-334. 

The kinetics of cell growth/death under free and/or immobilized states assume a relevant role in the assessment of the amount of biophase present in the reactor. Obviously, the kinetics depends strongly on the carbon/energy source available in wastewaters or purposely added. With the exception of consortia collected from anaerobic digesters, single strain cultures used in azo-dye conversion are characterized by hindered growth under anaerobic conditions [26, 29, 41], For these biosystems, the duration of the anaerobic stage must be carefully monitored to preserve cell viability. 

Gonzalez-Murua, C., A. Munoz-Rueda, F. Hernando, and M. Sanchez-Diaz. 1985. Effect of atrazine and methabenzthiazuron on oxygen evolution and cell growth of Chlorella pyrenoidosa. Weed Res. 25 61-66. Gorge, G. and R. Nagel. 1990. Toxicity of lindane, atrazine, and deltamethrin to early life stages of zebrafish (Brachydanio rerio). Ecotoxicol. Environ. Safety 20 246-255. 

The actual number of cells or percentage of microbial population that will be killed by an absorbed radiation dose depends also on various factors such as the inherent resistance of the particular organism, the growth stage, as well as environmental factors such as tem-... 

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