Browsing by Author "Mirth, Christen"
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- The developmental control of size in insectsPublication . Nijhout, H. Frederik; Riddiford, Lynn M.; Mirth, Christen; Shingleton, Alexander W.; Suzuki, Yuichiro; Callier, VivianeThe mechanisms that control the sizes of a body and its many parts remain among the great puzzles in developmental biology. Why do animals grow to a species-specific body size, and how is the relative growth of their body parts controlled to so they grow to the right size, and in the correct proportion with body size, giving an animal its species-characteristic shape? Control of size must involve mechanisms that somehow assess some aspect of size and are upstream of mechanisms that regulate growth. These mechanisms are now beginning to be understood in the insects, in particular in Manduca sexta and Drosophila melanogaster. The control of size requires control of the rate of growth and control of the cessation of growth. Growth is controlled by genetic and environmental factors. Insulin and ecdysone, their receptors, and intracellular signaling pathways are the principal genetic regulators of growth. The secretion of these growth hormones, in turn, is controlled by complex interactions of other endocrine and molecular mechanisms, by environmental factors such as nutrition, and by the physiological mechanisms that sense body size. Although the general mechanisms of growth regulation appear to be widely shared, the mechanisms that regulate final size can be quite diverse.
- The Ol1mpiad: concordance of behavioural faculties of stage 1 and stage 3 Drosophila larvae.Publication . Almeida-Carvalho, Maria J.; Berh, Dimitri; Braun, Andreas; Chen, Yi-chun; Eichler, Katharina; Eschbach, Claire; Fritsch, Pauline M. J.; Gerber, Bertram; Hoyer, Nina; Jiang, Xiaoyi; Kleber, Jörg; Klämbt, Christian; König, Christian; Louis, Matthieu; Michels, Birgit; Miroschnikow, Anton; Mirth, Christen; Miura, Daisuke; Niewalda, Thomas; Otto, Nils; Paisios, Emmanouil; Pankratz, Michael J.; Petersen, Meike; Ramsperger, Noel; Randel, Nadine; Risse, Benjamin; Saumweber, Timo; Schlegel, Philipp; Schleyer, Michael; Soba, Peter; Sprecher, Simon G.; Tanimura, Teiichi; Thum, Andreas S.; Toshima, Naoko; Truman, Jim W.; Yarali, Ayse; Zlatic, MartaMapping brain function to brain structure is a fundamental task for neuroscience. For such an endeavour, the Drosophila larva is simple enough to be tractable, yet complex enough to be interesting. It features about 10,000 neurons and is capable of various taxes, kineses and Pavlovian conditioning. All its neurons are currently being mapped into a light-microscopical atlas, and Gal4 strains are being generated to experimentally access neurons one at a time. In addition, an electron microscopic reconstruction of its nervous system seems within reach. Notably, this electron microscope-based connectome is being drafted for a stage 1 larva - because stage 1 larvae are much smaller than stage 3 larvae. However, most behaviour analyses have been performed for stage 3 larvae because their larger size makes them easier to handle and observe. It is therefore warranted to either redo the electron microscopic reconstruction for a stage 3 larva or to survey the behavioural faculties of stage 1 larvae. We provide the latter. In a community-based approach we called the Ol1mpiad, we probed stage 1 Drosophila larvae for free locomotion, feeding, responsiveness to substrate vibration, gentle and nociceptive touch, burrowing, olfactory preference and thermotaxis, light avoidance, gustatory choice of various tastants plus odour-taste associative learning, as well as light/dark-electric shock associative learning. Quantitatively, stage 1 larvae show lower scores in most tasks, arguably because of their smaller size and lower speed. Qualitatively, however, stage 1 larvae perform strikingly similar to stage 3 larvae in almost all cases. These results bolster confidence in mapping brain structure and behaviour across developmental stages.