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Bacterial growth curve\Kinetic Curve. In autecological studies, the growth of bacteria (or other microorganisms, as protozoa, microalgae or yeasts) in batch culture can be modeled with four different phases: lag phase (A), log phase or exponential phase (B), stationary phase (C), and death phase (D).
Figure 1: A bi-phasic bacterial growth curve.. A growth curve is an empirical model of the evolution of a quantity over time. Growth curves are widely used in biology for quantities such as population size or biomass (in population ecology and demography, for population growth analysis), individual body height or biomass (in physiology, for growth analysis of individuals).
A diauxic growth curve refers to the growth curve generated by an organism which has two growth peaks. The theory behind the diauxic growth curve stems from Jacques Monod's Ph.D. research in 1940. A simple example involves the bacterium Escherichia coli ( E. coli ), the best understood bacterium.
This open system allows researchers to maintain the exponential growth phase of cells for use in physiological experiments. [ 1 ] A chemostat (from chem ical environment is stat ic) is a bioreactor to which fresh medium is continuously added, while culture liquid containing left over nutrients, metabolic end products and microorganisms is ...
As resources become more limited, the growth rate tapers off, and eventually, once growth rates are at the carrying capacity of the environment, the population size will taper off. [6] This S-shaped curve observed in logistic growth is a more accurate model than exponential growth for observing real-life population growth of organisms. [8]
If an enzyme that is part of a rate-limiting step of microbial growth is substrate inhibited, then the cell growth will be inhibited in the same manner. However, the mechanisms are often more complex, and parameters for a model equation need to be estimated from experimental data. [ 1 ]
The method of enumeration [9] of surviving cells used by VCC is termed quantitative growth kinetics (QGK). It relates the kinetic time taken for the turbidity of a bacterial batch microbiological culture in a well of a 96-well microplate to reach a threshold difference in turbidity to a 10-fold dilution series of calibration growth curves.
Run-and-tumble motion is a movement pattern exhibited by certain bacteria and other microscopic agents. It consists of an alternating sequence of "runs" and "tumbles": during a run, the agent propels itself in a fixed (or slowly varying) direction, and during a tumble, it remains stationary while it reorients itself in preparation for the next run.