scholarly journals Energetic stress and infection generate immunity-fecundity tradeoffs in Drosophila

2018 ◽  
Author(s):  
Justin L. Buchanan ◽  
Colin D. Meiklejohn ◽  
Kristi L. Montooth

AbstractPhysiological responses to short-term environmental stress, such as infection, can have long-term consequences for fitness, particularly if the responses are inappropriate or nutrient resources are limited. Genetic variation affecting energy acquisition, storage, and usage can limit cellular energy availability and may influence resource-allocation tradeoffs even when environmental nutrients are plentiful. Here, we utilize well-characterized Drosophila mitochondrial-nuclear genotypes to test whether disrupted energy metabolism interferes with nutrient-sensing pathways, and whether this disruption has consequences for tradeoffs between immunity and fecundity. We find that this energetically compromised genotype is resistant to rapamycin – a drug that stimulates nutrient-sensing pathways that are activated when resources are limited. Resource limitation also compromises survival in energetically-compromised genotypes, suggesting that this genotype may have little excess energetic capacity and fewer cellular nutrients, even when environmental nutrients are not limiting. Accordingly, we find that immune function is compromised in this genotype, but only in females, and that these females experience immunity-fecundity tradeoffs that are not evident in genotypic controls with normal energy metabolism. Thus, genetic variation in energy metabolism may act to limit the resources available for allocation to life-history traits in ways that generate tradeoffs even when environmental resources are not limiting.

Genetics ◽  
1997 ◽  
Vol 146 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Michael Travisano

The effect of environment on adaptation and divergence was examined in two sets of populations of Escherichia coli selected for 1000 generations in either maltose- or glucose-limited media. Twelve replicate populations selected in maltose-limited medium improved in fitness in the selected environment, by an average of 22.5%. Statistically significant among-population genetic variation for fitness was observed during the course of the propagation, but this variation was small relative to the fitness improvement. Mean fitness in a novel nutrient environment, glucose-limited medium, improved to the same extent as in the selected environment, with no statistically significant among-population genetic variation. In contrast, 12 replicate populations previously selected for 1000 generations in glucose-limited medium showed no improvement, as a group, in fitness in maltose-limited medium and substantial genetic variation. This asymmetric pattern of correlated responses suggests that small changes in the environment can have profound effects on adaptation and divergence.


2007 ◽  
Vol 177 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Vincent Mirouse ◽  
Lance L. Swick ◽  
Nevzat Kazgan ◽  
Daniel St Johnston ◽  
Jay E. Brenman

LKB1 is mutated in both familial and spontaneous tumors, and acts as a master kinase that activates the PAR-1 polarity kinase and the adenosine 5′monophosphate–activated kinase (AMPK). This has led to the hypothesis that LKB1 acts as a tumor suppressor because it is required to maintain cell polarity and growth control through PAR-1 and AMPK, respectively. However, the genetic analysis of LKB1–AMPK signaling in vertebrates has been complicated by the existence of multiple redundant AMPK subunits. We describe the identification of mutations in the single Drosophila melanogaster AMPK catalytic subunit AMPKα. Surprisingly, ampkα mutant epithelial cells lose their polarity and overproliferate under energetic stress. LKB1 is required in vivo for AMPK activation, and lkb1 mutations cause similar energetic stress–dependent phenotypes to ampkα mutations. Furthermore, lkb1 phenotypes are rescued by a phosphomimetic version of AMPKα. Thus, LKB1 signals through AMPK to coordinate epithelial polarity and proliferation with cellular energy status, and this might underlie the tumor suppressor function of LKB1.


2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Pierre-Yves Plaçais ◽  
Éloïse de Tredern ◽  
Lisa Scheunemann ◽  
Séverine Trannoy ◽  
Valérie Goguel ◽  
...  

2009 ◽  
Vol 276 (1663) ◽  
pp. 1845-1854 ◽  
Author(s):  
Arild Husby ◽  
Loeske E.B. Kruuk ◽  
Marcel E. Visser

For multiple-brooded species, the number of reproductive events per year is a major determinant of an individual's fitness. Where multiple brooding is facultative, its occurrence is likely to change with environmental conditions, and, as a consequence, the current rates of environmental change could have substantial impacts on breeding patterns. Here we examine temporal population-level trends in the proportion of female great tits ( Parus major ) producing two clutches per year (‘double brooding’) in four long-term study populations in The Netherlands, and show that the proportion of females that double brood has declined in all populations, with the strongest decline taking place in the last 30 years of the study. For one of the populations, for which we have data on caterpillar abundance, we show that the probability that a female produces a second clutch was related to the timing of her first clutch relative to the peak in caterpillar abundance, and that the probability of double brooding declined over the study period. We further show that the number of recruits from the second clutch decreased significantly over the period 1973–2004 in all populations. Our results indicate that adjustment to changing climatic conditions may involve shifts in life-history traits other than simply the timing of breeding.


1998 ◽  
Vol 800 (1) ◽  
pp. 114-124 ◽  
Author(s):  
Jean-François Doriat ◽  
Violette Koziel ◽  
Anne-Claude Humbert ◽  
Jean-Luc Daval

2017 ◽  
Vol 233 (4) ◽  
pp. 3465-3475 ◽  
Author(s):  
Weinan Zhou ◽  
Deepti Ramachandran ◽  
Abdelhak Mansouri ◽  
Megan J. Dailey

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