Where P C lKNO3 and P Cl Urrea represent the productivity in chlorophyll with KNO 3 and urea, respectively, as function of the codified values of the light intensity ( X 1 ) and temperature ( X 2 ). Looking at the figures related to these productivities ( Figures 3 and and4), 4 ), it is clear that for both nitrogen sources it was possible to obtain the maximum point of the function without the range under study. As the chlorophyll productivity is a function of the total quantity of chlorophyll produced, it is expected that the chlorophyll productivity for tests performed with KNO 3 as nitrogen source would be a linear function of variable X 1 . However, this did not occur, as although with the increase of light intensity it was possible to obtain higher cell concentrations and consequently an increase of total quantity of produced chlorophyll, this increase would occur with a corresponding increase of cultivation time. Thus, there would be an intermediate light intensity that would maximize the relation between the produced total chlorophyll concentration and the corresponding time. As related to cultivation with urea, the same productivity relation occurred in chlorophyll with X 1 than the one identified for total chlorophyll ( Figure 2 ), and this probably is due to the fact that the increase of light intensity above the evaluated intermediate value does not result in a gain of maximum cell concentration ( Figure 1 ), or in a significant increase of productivity ( Figure 2 )
We have begun to utilize deletion network analyses to propose the architecture of multiprotein complexes and to determine the modularity of protein complexes. In our initial publication in this area, we analyzed the Rpd3/Sin3 histone deacetylase complexes. Here, Rpd3 was used as an affinity purification bait and protein complexes were analyzed from a wild type background and in strains where different subunits of the complex where deleted. Using this approach we were able to propose an architectural model for the Rpd3/Sin3 histone deacetylase complexes (Sardiu et al., 2009). More recently, we have expanded this approach for the analysis of the SAGA and ADA chromatin remodeling complexes (Lee et al., 2011).