Bacterial growth, phases

Pohlmann-Dietze, P., Ulrich, M., Kiser, K.B., et al. (2000) Adherence of Staphylococcus aureus to endothelial cells influence of capsular polysaccharide, global regulator agr, and bacterial growth phase. Infect Inunun 68, 4865-4871. 

Log phase Period of bacterial growth with logarithmic increase in cell number. 

Fig. 1.12 Typical bacterial growth curve A, lag phase B, log phase C, stationary phase D, phase of decline.

Bacterial growth on well screen and formation. Emulsification of two fluid phases. 

With the suggestion that the last common genetic ancestor is a hyperthermophile, the role of temperature on the origins of life is important. The lower temperature limit in water is limited by the phase transition from liquid to ice. This is a problem because the density of ice is lower than that of water and the increase in volume on freezing will cause the cell structure to become disrupted in the same way that pipes burst in the winter. The lower limit for bacterial growth reported so far is -20°C, which is the temperature at which intracellular ice is formed. Adaptation to the cold requires a considerable salt content to depress the melting point of water the Don Juan Pond in Antarctica, which has a saturated CaCE solution, preserves the liquid phase at temperatures as low as —53°C. 

Three-phase fluidized bed reactors are used for the treatment of heavy petroleum fractions at 350-600 C and 200 atm. A biological treatment process (Dorr-01iver Hy-Flo) employs a vertical column filled with sand on which bacterial growth takes place while waste liquid and air are charged. A large... 

Do not use aqueous buffered mobile phase older than 10 days because of the increased risk of bacterial growth, which can damage the HPLC column. ... 

Alice et al studied the turnover kinetics of Listeria OTonocytogenex-secreted p60 protein (a murein hydrolase) by host cell cytosolic proteasomes. J774 cells, seeded in flasks and incubated overnight in culture medium, were infected with log-phase cultures of E. monocytogenes for 30 min, washed, and incubated in culture medium for 3 h, with gentamicin (50 tg/ml) added after the first 30 min to inhibit extracellular bacterial growth. Cells then were washed and placed in methionine-free medium with spectinomycin, gentamicin, the eukaryotic protein synthesis inhibitors [cycloheximide (50 tg/mL) and anisomycin (30 tg/ml),] and 25 dVI calpain inhibitor I. After 30 min, [ S]methionine was added, and the cells were pulse-labeled for periods of 20 to 60 min. Cells... 

The study of the DNA content, an indication of bacterial growth, shows that S. badius reaches its stationary phase after 5 days, 7 days prior to S. viridosporus (Fig. 3). In both cases, APPL production starts immediately (t = 0) and increases linearly during incubation, S. badius producing more than S. viridosporus. After 35 days, the APPL yield represents 7% and 5% of the initial Indulin ATR weight for S. badius and S. viridosporus, respectively. 

Cultivation. The cells are transferred from the cryogenic cell bank to a liquid nutrient medium, where they are allowed to reproduce. Mammalian cells such as CHO divide about once every 24 h (bacterial cells, such as Escherichia coli, usually divide once every 20 min, and thus a sufficient number of cells are obtained in a much shorter time than in traditional fermentation processes). During the growth phase the cell culture is transferred to progressively larger culture vessels. 

The emulsification state of water in butter (i.e. the water droplet size) is very important for the quality of the product. Bacteria in butter can grow only in the aqueous emulsified phase. A finely divided aqueous phase restricts bacterial growth since the nutrients available in small droplets will quickly become limiting. Also, unless bacterial contamination is high, it is likely that most small water droplets in butter are sterile. 

In the freezer, another phase change is at work storing food over long periods of time. When food is frozen, any bacterial growth in the food completely stops bacteria become inactive at freezing temperatures. At the same time, the process of freezing changes the state of the matter. 

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