Zakrzewska 2011 MCB, tradeoff between growth rate and cellular robustness

Zakrzewska11 found a inverse correlation between growth rate and stress tolerance using yeast deletion collection. Cellular functions required for stress tolerance, independent of the growth rate, include vesicular transport, Rpd3 histone deacetylase complex, mitoic cell cycle.

Zakrzewska11 studied heat, acid, oxidative stresses as stress factors.

The study used BY4741, two hours exposure to 39C, 10C, 0.15mM H2O2, 1.2mM sorbic acid at pH5.0. The control culture is at 30C.   The second stress was 327mM acetic acid at pH3.0, 10mM H2O2, or 48C for 10 minutes.

Zakrzewska11 used barcoded yeast deletion collection and Affymetrix chip to conduct the genome-wide measures. Each knock-out strain is usually represented by 4 values. Both growth rate and survival rates were measured by barcodes. Synthetic complete medium was used. The first time point is t=-6 hours, with cell density of 2x10^5 cells/ml. The second timepoint is t=-3 hours. The 38C heat shock started at t=-3 hours and lasted till t=0 hours.  Linear regressions were applied with these 3 time points, and its slope is the calculated growth rate (1/hr).

Zakrzewska11 provided Excel data of growth rate and survival data for 4066 null mutants in file 'mc-E10-08-0721-s06.xls'. The 'growth rates' sheet,

contain 'mu30' and 'mu38', which are probably the growth rates (slopes of -6, -3, and 0 hr hybridization signals). Mostly 'mu30' > 'mu38' as expected, but sometimes 'mu30' < 'mu38' that may suggest heat-tolerance or heat-adaptation.  The 'survival % 95% CI' sheet contains data that were measured after a 10 minute treatment with 10 mM H2O2 (oxi), 327 mM acetic acid at pH 3.0 (acid) or 48oC (heat), compared with CFU counts of an untreated control.

This was done after growth at 30C, as well as after a 3 hour 38C pretreatment. Each temperature has 3 replicates. The columns of "<95%" and ">95%" are not clear to me and I wonder what they mean.

Raw data are available at 

http://www.uva.nl/over-de-uva/organisatie/medewerkers/content/s/m/g.j.smits/g.j.smits.html
I downloaded 'log transformed viability for website.xls' and 'raw data for website.xls'.  The first seems to be the calculations, and the second seems to contain the original raw data.

Note: Deep sequencing may provide better information than bar-code and hybridization.

References:
http://www.molbiolcell.org/content/22/22/4435.full

http://www.uva.nl/over-de-uva/organisatie/medewerkers/content/s/m/g.j.smits/g.j.smits.html