Log phase

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

The exponential (log) phase (up to 8-10 hours) where cells multiply most rapidly ... 

Fig. 6 shows a fed batch fermentation of sweet sorghum juice (SSJ) by Bacillus aryabhattai in 3 L fermentor under cultivating condition with agitation rate at 200 rpm, air rate of 1.5 1/min, at 30° C and feeding time at 18 and 24 hr during log phase of the culture. It was found that the cell could continuously produce both biomass and PHAs. Maximum cells were obtained at about 14.20 g/1 at 54 hr when PHAs content reached 4.84 g/1 after 66 hr (Tanamool et al., 2011). In addition, in Table 2, fed batch fermentation by A, latus was used for the production of PHAs (Yamane et al, 1996 Wang Lee, 1997). It could yield high productivity with the use of cheap carbon sources. 

E.coli K12 TGI were grown to log phase (up to OD6oo=0.20-0.30) in Luria-Bertani (LB) broth, washed and ultimately concentrated 25 times in ice-cold 100 mM of CaCb. DNA was extracted from agarose gel after electrophoresis, added to 200 ml of competent cell and incubated at 0°C for 15 min. The cell-DNA complex was transferred to 42°C for exactly 90 s and was rapidly chilled in ice. Then 1000 ml LB-broth was added and the cells were incubated at 37°C for 60 min. 100 ml cells was spread on LB-agar with and without selective marker ampicillin (50 mg/ml), to obtain the number of transformants and viable cells respectively. Plates were incubated at 37°C for 18-24 h. 

E.coli recA y.luxCDABE strain were grown for 16-18 hours at 37°C in LB-broth in the presence of 20 pg/ ml of ampicillin. Immediately before the experiment the culture was diluted 1 20 by fresh culture medium and incubated until early log-phase. The grown biomass was mixed with AR solutions in final concentrations of ICfs, ICH n ICfs M, with used for their dilution with distilled water (control) and incubated for 60 minutes. The luminescence intensity of UV-irradiated E.coli recA lux and intact specimens were registered by plate bioluminometer LM OIT (Immimotech, Czech Rep.) in a real time. The number of viable cells was determined from the colony-forming units (CFU) on a surface of a LB-agar after the subsequent incubation within 24 hours at 37 °C. A quantitative estimation of an induction of the SOS-system calculated on formula... 

In phase B it is assumed that the inoculum has adapted itself to the new environment and growth then proceeds, each cell dividing into two. Cell division by binary fission may take place every 15-20 minutes and the increase in numbers is exponential or logarithmic, hence the name log phase. Phase C, the stationary phase, is thought to occur as a result of the exhaustion of essential nutrients and possibly the accumulation... 

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

The second set of experiments featured very controlled growth conditions and relatively small (5 ml) cultures. All tubes were inoculated with a similar number of cells (based on OD600 measurements) and incubated for only 5 hours instead of 24. Their optical densities ranged from 1.33 (for the control) to 3.57 (for isolate 1). If MRSA is assumed to behave similar to E. coli, all eight MRSA cultures should have been in log phase when analyzed. Representative spectra from these eight cultures appear in Figure 9.6 and crosscorrelation results appear in Table 9.3. 

Grow cells in media to a density of about ODgoonm = 1-2 and harvest in mid-log phase. Centrifuge cells at 3,200rpm to pellet them and wash 3 times with ice-cold PBS (150mM sodium phosphate, lOOmM NaCl, pH 7.5). 

Exponential growth, where log Y =A(BX), such as the growth curve for the log phase of a bacterial culture. 

Prepare a cell suspension in growth medium from a healthy, log-phase culture. 

Log-phase culture of HeLa or some other rapidly growing mammalian cell line (American Type Culture Collections, Rockville, MD). 

To a log-phase monolayer culture of HeLa cells, add sufficient stock colchicine solution to give a final concenttation of 0.06 pg/mL. 

D. Washo-Stultz, C. Crowley, C. M. Payne, C. Bernstein, S. Marek, E. W. Gerner and H. Bernstein, Increased susceptibility of cells to inducible apoptosis during growth from early to late log phase an important caveat for in vitro apoptosis research, Toxicol. Lett., 2000, 116(3), 199. 

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... 

Saccharomyces cerevisiae JDl, mitotic gene conversion in stationary and log-phase cultures... 

Lobry de Bruyn-Alberda van Ekenstein transformation 693 Lock and key theory 478 Log phase of growth 470 Lon protease 628 Loricin 439... 

Figure 7. Effects of various sera on ODC activity in KB cells. To log-phase KB cells, fresh media containing (a) no serum, (b) 10% calf serum, (c) 10% heat-inactivated calf serum, or (d) 10% dialyzed calf serum was added ft= 0). ODC activity then measured every 2 hr under each condition listed.

Methotrexate acts by inhibition of dihydrofolate reductase, the enzyme requisite for the reduction of dihydrofolic acid (3) to 5,6,7,8-tetrahydrofolic acid (4). In turn, (4) is a precursor to a series of enzyme cofactors (5-7) essential for the transfer of one carbon unit necessary for the biosynthesis of purines and pyrimidines and hence, ultimately, DNA. As an inhibitor of dihydrofolate reductase, methotrexate kills cells during the S phase of the cell cycle, when the cells are in the log phase of growth. Unfortunately, this cytotoxicity is non-selective, and rapidly proliferating normal cells, e.g., gastrointestinal epithelium cells and bone marrow, are dramatically affected as well. In addition, recent use of high dose methotrexate therapy with leucovorin rescue has led to additional clinical problems arising from a dose-related nephrotoxic metabolite, 7-hydroxy methotrexate (8). Finally, the very polar nature of methotrexate renders it virtually impenetrable to the blood-brain barrier, which can necessitate direct intrathecal injection in order to achieve therapeutic doses for the treatment of CNS tumours. 

Keep 25-cm2 T flasks of cells in log phase of growth by subdividing when almost confluent. Freezing should only be carried out when cells are less than confluent and appear healthy. 

Cells are in optimal condition for cryopreservation when they are in log-phase growth. This occurs when the cells are at low-to-medium density in CM that is not exhausted of nutrients. 

Two days before the actual separation procedure, transfer the carcinoma cells to new flasks to keep them in log phase growth (see Note 1). Use Accutase as described in step 2. 

Stage in the growth cycle when the mass of microbial cells doubles over each of the successive and equal time intervals. The doubling time and, therefore, the growth rate during the entire log phase is thus constant. Volume 1(6). 

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