Category:Team Frederick Griffith

Fig. 4(b) shows in a time lapse experiment that the concentration of ADP increases and the concentration of ATP decreases suggesting that gpA-ΔN179 contains an ATPase site.

Fig. 3 shows that a mutated gpA is unable to properly cut at the cos site, thus preventing viral DNA packaging.

Figure 1B is a western blot which shows the cleavage of BiP by SubAB over a time span of 60 minutes. The antibody used was polyclonal goat anti-BiP. At 20 minutes the band at 28-kDa (part of the cleaved protein) became evident and by 30 minutes it was evident that the band at 72-kDa (the intact protein) had become diminished. Only one cleavage fragment was visible because when the antibody was made, it was made against a peptide from the C-terminus of BiP so only the intact and C terminal portion of the protein would bind to the antibody and produce a band.

Figure 5 shows a western blot looking at the effect SubAB has on the levels of cyclin D1, cyclin D3, Cdk4, and Cdk6. This experiment was done to examine the underlying cause of cell cycle arrest. A significant downregulation of cyclin D1 occurred between 30 and 60 minutes after exposure to SubAB. Cyclin D is a G1 cyclin and the downregulation of cyclin D1 led to arrest in G1 of the cell cycle.

The results of FACS (fluorescence activated cell sorting) is shown in figure 4. HeLa cells were treated with SubAB and by hour 20 it was evident that there was a definite increase in the number of cells in G0-G1 phase compared to time 0 as well as a decrease in the number of cells in the other stages. Figure 4 shows that SubAB causes cells to arrest in G1.

Figure 2A shows that at the pH values 7.0, 6.2, and 5.5 the OD600 rapidly increased between 8 and 24 h of incubation reaching at 48 h the maximum values, corresponding to cell concentrations between 9.2 and 8.8 log CFU/mL. Also, in Figure in 3A, histamine rapidly accumulated at pH 7.0, 6.2, and 5.5 and a maximum concentration of about 350 mg/L was reached after 24 h. In both cases the production of histamine increased concomitantly with the cell number with a relatively small further rise during the stationary phase. In all cultures the maximum histamine levels were reached at the end of active growth. Histamine was detectable (10 to 55 mg/L) even when growth was strongly inhibited.The HdcA decarboxylase of this strain is very active since the exponential phase under different conditions characterizing the 1st step of the cheesemaking process. In addition, the enzyme is even more active outside the cells and its action is not significantly limited by the conditions found during the cheese ripening process. In this framework, the death and lysis of the starter cultures can be a factor which strengthens the risk of histamine accumulation during cheese ripening when temperature, pH, and NaCl concentration allow an intense activity of this HdcA enzyme.