Bacterial growth

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Related to Log phase: Stationary phase, death phase

Bacterial growth

The processes of both the increase in number and the increase in mass of bacteria. Growth has three distinct aspects: biomass production, cell production, and cell survival. Biomass production depends on the physical aspects of the environment (water content, pH, temperature), the availability of resources (carbon and energy, nitrogen, sulfur, phosphorus, minor elements), and the enzymatic machinery for catabolism (energy trapping), anabolism (biosynthesis of amino acid, purines, pyrimidines, and so forth), and macromolecular synthesis [proteins, ribonucleic acid (RNA), and deoxyribonucleic acid (DNA)]. Cell production is contingent on biomass production and involves, in addition, the triggering of chromosome replication and subsequent cell division. The cells may or may not separate from each other, and the division may partition the cell evenly or unevenly. Alternatively, growth may occur by budding (unequal division). Most cells so produced are themselves capable of growing and dividing; consequently, viability is usually very high when growth conditions are favorable. Moreover, in many cases the incidence of death is surprisingly low in the absence of needed nutrients. Many bacteria differentiate into resistant resting forms (such as spores); others may simply reduce their rate of metabolism and persist in the vegetative state for long times.

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.
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When exposed to log phase liquid cultures of Roseivivax sp.
46E8 filtrates from both log phase growth ([A.sub.595] range 0.537-0.655) and stationary phase growth ([A.sub.595] range 1.152-1.460) revealed small (<0.2 [micro]m) DNA-containing particles (Fig.
A suspension of approximately 2 x [10.sup.6] cells per mL at log phase was treated with Mdc (0-2 x MIC) Mdc and incubated at 37[degrees]C for 0-120 min.
The growth curve of ADMS cells was determined at passage 6 by using the MTT assay (C); an initial lag phase of 2 days, a log phase from day 3 to day 5, and a plateau phase.
tuberculosis strains were cultured to Log phase, and 1 x [10.sup.6] cells were exposed to the corresponding medium containing serial 2-fold dilutions DQYD for indicated times.