DOI: 10.5285/3ef187b8-3471-42ab-bc5d-d7e5e6f5d575
title: Growth rates and specific cellulase activities of Antarctic Pseudogymnoascus roseus isolates exposed to constant and fluctuating temperatures.

description: Data on the growth rates and specific cellulase activities of 10 isolates of the fungus Pseudogymnoascus roseus from sub- and maritime Antarctica, exposed in vitro to fluctuating temperatures of 2-15 degrees Celsius, 2-18 degrees Celsius, 2-21 degrees Celsius and 2-24 degrees Celsius and their constant mean temperatures of 9.0 degrees Celsius, 10.7, 12.0 or 13.1 degrees Celsius, respectively. The 10 isolates of P. roseus were obtained from soils at Lewis Pass on South Georgia, The Backslope on Signy Island, Walton Terraces on Leonie Island and Mars Oasis on Alexander Island.
description: A total of 10 isolates of P. roseus were obtained from soils at Lewis Pass on South Georgia (two isolates, SG1 and SG2), The Backslope on Signy Island (two isolates, S1 and S2), Walton Terraces on Leonie Island (three isolates, L1-L3) and Mars Oasis on Alexander Island (three isolates, A1-A3). They were maintained on half-strength potato dextrose medium. Isolates were then inoculated onto soil extract medium in Petri dishes, which were incubated at temperatures fluctuating daily from 2-15 degrees Celsius, 2-18 degrees Celsius, 2-21 degrees Celsius and 2-24 degrees Celsius, and at constant temperatures of 9.0 degrees Celsius, 10.7 degrees Celsius, 12.0 degrees Celsius or 13.1 degrees Celsius, respectively. The constant temperatures were the means of the fluctuating temperatures (i.e., 9.0 degrees Celsius was the mean of the temperatures fluctuating from 2-15 degrees Celsius, 10.7 degrees Celsius was the mean of the temperatures fluctuating from 2-18 degrees Celsius, 12.0 degrees Celsius was the mean of the temperatures fluctuating from 2-21 degrees Celsius, and 13.1 degrees Celsius was the mean of the temperatures fluctuating from 2-24 degrees Celsius). Four replicate dishes per isolate were incubated at each temperature. Radial hyphal extension rates of colonies (referred to as growth rates) were recorded in one experiment at 15 x magnification under a dissecting microscope at 0-48 hours and were expressed as mm / day. Growth rates were also measured in another experiment, again at 15 x magnification, every 3-5 days at 7-28 days after inoculation, and were calculated by regressing colony radii against time (r2 of all fits more than or equal to 95 percent). At 28 d, extracellular beta-glucosidase (cellulase) was extracted from colonies in 10 mM phosphate buffer. Protein concentrations in the buffer were measured using a Micro BCA Protein Assay (Thermofisher). Cellulase activity was measured and expressed as nmol of p-nitrophenol released from 4-nitrophenyl-beta-D-glucopyranoside min-1 micro-grammes-1 protein (Misiak et al., 2021).
description: Micro BCA Protein Assay (Thermofisher)
description: Data have not been cleaned. Data losses, indicated by MD (missing data) were caused by laboratory errors. Note that the accuracy of growth rate data measured at 12 degrees Celsius and 2-21 degrees Celsius over 0-48 hours was lower than for other growth rate data.