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Université de Fribourg

Counting calories in Drosophila diet restriction

Min, Kyung-Jin ; Flatt, Thomas ; Kulaots, Indrek ; Tatar, Marc

In: Experimental Gerontology, 2006, vol. 42, no. 3, p. 247-251

The extension of life span by diet restriction in Drosophila has been argued to occur without limiting calories. Here we directly measure the calories assimilated by flies when maintained on full- and restricted-diets. We find that caloric intake is reduced on all diets that extend life span. Flies on low-yeast diet are long-lived and consume about half the calories of flies on high-yeast diets,...

Université de Fribourg

What is metamorphosis?

Bishop, C. D. ; Erezyilmaz, D. F. rsity ; Flatt, Thomas ; Georgiou, C. D. ; Hadfield, M. G. ; Heyland, A. ; Hodin, J. ; Jacobs, M. W. ; Malakova, S. A. ; Pires, A. ; Reitzel, A. M. ; Santagata, S. ; Tanaka, K. ; Youson, J. H.

In: Integrative and Comparative Biology, 2006, vol. 46, no. 6, p. 655–661

Metamorphosis (Gr. meta- “change” + morphe “form”) as a biological process is generally attributed to a subset of animals: most famously insects and amphibians, but some fish and many marine invertebrates as well. We held a symposium at the 2006 Society for Integrative and Comparative Biology (SICB) annual meeting in Orlando, FL (USA) to discuss metamorphosis in a comparative context....

Université de Fribourg

A role for genetic accommodation in evolution?

Braendle, Christian ; Flatt, Thoams

In: BioEssays, 2006, no. 28, p. 868-873

Whether evolutionary change can occur by genetic assimilation, or more generally by genetic accommodation, remains controversial. Here we examine some of the experimental evidence for both phenomena. Several experiments in Drosophila suggest that assimilation is possible, and a new paper1 shows that a color polyphenism in the tobacco hornworm, Manduca sexta, can evolve by genetic accommodation....

Université de Fribourg

Juvenile and Steroid Hormones in Drosophila melanogaster Longevity

Flatt, Thomas ; Tu, Meng-Ping ; Tatar, Marc

In: The Handbook of the Biology of Aging, 2006, p. 415-448

This chapter reviews hormonal effects on aging in Drosophila melanogaster. The insect juvenile hormone (JH) is a sesquiterpenoid compound produced by the corpora allata (CA), a pair of endocrine glands with nervous connections to the brain. In pre-adult development and metamorphosis, JH functions as a "status quo" hormone, allowing continued growth after ecdysteroid-induced molting. Metamorphosis...

Université de Fribourg

Evolution in group-structured populations can resolve the tragedy of the commons

Killingback, Timothy ; Bieri, Jonas ; Flatt, Thomas

In: Proceeding of the Royal Society, 2006, no. 273, p. 1477–1481

Public goods are the key features of all human societies and are also important in many animal societies. Collaborative hunting and collective defence are but two examples of public goods that have played a crucial role in the development of human societies and still play an important role in many animal societies. Public goods allow societies composed largely of cooperators to outperform...

Université de Fribourg

Comparing thyroid and insect hormone signaling

Flatt, Thomas ; Moroz, Leonid L. ; Tatar, Marc ; Heyland, Andreas

In: Integrative and Comparative Biology, 2006, vol. 46, no. 6, p. 777-794

Transitions between different states of development, physiology, and life history are typically mediated by hormones. In insects, metamorphosis and reproductive maturation are regulated by an interaction between the sesquiterpenoid juvenile hormone (JH) and the steroid 20-hydroxy-ecdysone (20E). In vertebrates and some marine invertebrates, the lipophilic thyroid hormones (THs) affect...

Université de Fribourg

Hormonal pleiotropy and the juvenile hormone regulation of Drosophila development and life history

Flatt, Thomas ; Tu, Meng-Ping ; Tatar, Marc

In: BioEssays, 2005, vol. 27, no. 10, p. 999-1010

Understandinghowtraits are integrated at the organismal level remains a fundamental problem at the interface of developmental and evolutionary biology. Hormones, regulatory signaling molecules that coordinate multiple developmental and physiological processes, are major determinants underlying phenotypic integration. The probably best example for this is the lipid-like juvenile hormone (JH) in...

Université de Fribourg

Effect of aging on thermal conductivity of fiber-reinforced aerogel composites: An X-ray tomography study

Iswara, Subramaniam ; Griffa, Michele ; Kaufmann, Rolf ; Beltran, Mario ; Huber, Lukas ; Brunner, Samuel ; Lattuada, Marco ; M.Koebel, Matthias ; Malfait, Wim J.

In: Microporous and Mesoporous Materials, 2019, vol. 278, p. 289–296

Silica aerogels display an ultra-low thermal conductivity (λ) and are used as thermal superinsulators. Here, we study the influence of aging and drying processes on the microstructure and thermal conductivity of fiber-reinforced silica aerogel composites. Glass wool-silica gel composites were aged for variable times, hydrophobized, and dried either at ambient pressure or from supercritical...

Université de Fribourg

Heating behavior of magnetic iron oxide nanoparticles at clinically relevant concentration

Lemal, Philipp ; Balog, Sandor ; Geers, Christoph ; Taladriz-Blanco, Patricia ; Palumbo, Andrea ; M.Hirt, Ann ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Journal of Magnetism and Magnetic Materials, 2019, vol. 474, p. 637–642

Magnetic hyperthermia for cancer treatment has gained significant attention in recent years, due to its biocompatibility of applied nanoparticles and the possibility for spatially localized heating in deep tissues. Clinical treatments use nanoparticle concentrations of 112 mg Fe/mL, while the concentrations experimental studies have addressed are considerably smaller, usually between 0.1...

Université de Fribourg

Emergence of nanoplastic in the environment and possible impact on human health

Lehner, Roman ; Weder, Christoph ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara

In: Environmental Science & Technology, 2019, vol. 53, no. 4, p. 1748–1765

On account of environmental concerns, the fate and adverse effects of plastics have attracted considerable interest in the past few years. Recent studies have indicated the potential for fragmentation of plastic materials into nanoparticles, i.e., “nanoplastics,” and their possible accumulation in the environment. Nanoparticles can show markedly different chemical and physical properties...