QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online October 5, 2006
Journal of Experimental Biology 209, 3964-3973 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02463

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JEB Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Folk, D. G. Articles by Gilchrist, G. W. Search for Related Content PubMed PubMed Citation Articles by Folk, D. G. Articles by Gilchrist, G. W.

Selection on knockdown performance in Drosophila melanogaster impacts thermotolerance and heat-shock response differently in females and males

Donna G. Folk^1,*, Patty Zwollo¹, David M. Rand² and George W. Gilchrist¹

¹ Department of Biology, College of William and Mary, Williamsburg, VA 23187, USA
² Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA

View larger version (12K): [in a new window]   Fig. 1. A diagrammatic depiction of the selection history of the original and newly established High TKD, Low TKD, and Control lines. Details of the selection history are discussed in Materials and methods.

View larger version (23K): [in a new window]   Fig. 2. Histograms of TKD for the newly established LN, CN and HN lines in generations 1 (top) and 12 (bottom). At generation 12, the flies had undergone 9 generations of knockdown selection. The error bars show s.e.m. values for groups of flies fractionated at 0.5°C intervals. Each LN, CN and HN group comprises four replicate populations. During knockdown, 1000 flies from each line are assayed for TKD; thus, each graph represents TKD frequency distribution for 4000 flies. The fitted line on each graph shows the maximum likelihood fit for a bimodal distribution. The fitted parameters for the distributions are listed in Table 1.

View larger version (14K): [in a new window]   Fig. 3. The effect of a heat-shock pretreatment on TKD. Each bar represents the difference (in °C) between the mean TKD of pretreated flies and the mean TKD of non-pretreated flies for the CN1–4, LN1–4, and HN1–4 lines. The values for the females are shown at the top, males at the bottom. Mean difference in TKD for females (and for males) from each line was estimated using 500 pretreated flies and 500 non-pretreated flies. Black bars, values for CN1–4; blue bars, LN1–4; red bars, HN1–4.

View larger version (8K): [in a new window]   Fig. 4. Pretreatment of flies (heat hardening) increases survivorship, measured by proportion of flies that are alive 24 h after thermal stress. HS=38.5°C heat shock for 1 h, with no pretreatment. Pre+HS=36°C heat hardening pretreatment for 1 h followed by a resting period (25°C for 1 h) prior to heat shock at 38.5°C for 1 h. Each data point represents the mean survivorship of 300 males or females (i.e. 75 flies from each of the four CN, LN or HN lines). Values are means ± s.e.m. Red lines depict change in survivorship in HN flies, with red filled triangles (pointing upward) for females; open triangles, males. Blue lines depict change in survivorship in LN flies, with blue filled triangles (pointing downward) for females; open triangles, males. Black lines depict changes in survivorship in the CN flies, with black filled circles for females; open circles, males.

View larger version (10K): [in a new window]   Fig. 5. Total HSC70/HSP70 protein content prior to (0 min) and at 10, 20, 30 and 60 min following a 36°C heat stress in female and male flies. Results are expressed relative to 5 ng HSP70 protein included as a standard (see Materials and methods). The data were adjusted for block effects of running western blots in groups. Solid red lines and red filled triangles, values for the HN females; solid blue lines and blue filled triangles, LN females; broken red lines and open red triangles, HN males; broken blue lines and open blue triangles, LN males. Values are mean ± s.e.m. of 8 samples (2 samples from each HN1–4 or LN1–4 line).