Fate predetermination of cardiac myocytes during zebrafish heart regeneration

Adult zebrafish have the remarkable ability to regenerate their heart upon injury, a process that involves limited dedifferentiation and proliferation of spared cardiomyocytes (CMs), and migration of their progeny. During regeneration, proliferating CMs are detected throughout the myocardium, including areas distant to the injury site, but whether all of them are able to contribute to the regenerated tissue remains unknown. Here, we developed a CM-specific, photoinducible genetic labelling system, and show that CMs labelled in embryonic hearts survive and contribute to all three (primordial, trabecular and cortical) layers of the adult zebrafish heart. Next, using this system to investigate the fate of CMs from different parts of the myocardium during regeneration, we show that only CMs immediately adjacent to the injury site contributed to the regenerated tissue. Finally, our results show an extensive predetermination of CM fate during adult heart regeneration, with cells from each myocardial layer giving rise to cells that retain their layer identity in the regenerated myocardium. Overall, our results indicate that adult heart regeneration in the zebrafish is a rather static process governed by short-range signals, in contrast to the highly dynamic plasticity of CM fates that takes place during embryonic heart regeneration

Isomerization of meso diamines into their C2 symmetrical d,l isomers

An efficient isomerization method is disclosed which allows the obtention of the useful d,l isomers of C2 symmetrical diamines, starting from their meso isomer

Practical and efficient synthesis of C2 symmetrical diamines with Zn/Me3SiCl

C2 symmetrical diamines are efficiently obtained by reductive coupling of imines with the couple Zn/Me3SiCl. This high yielding method is very practical and cheap for large scale preparation

Exploration Behavior and Morphology are Correlated in Captive Gray Mouse Lemurs (Microcebus murinus)

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Unusually facile palladium catalysed oxidation of imidazolidines and oxazolidines

An unusually facile palladium catalysed oxidation of imidazolidines is described, affording in good yield, the monoamide of the corresponding diamine or the corresponding imidazolines. Oxazolidines derived from ephedrine react similarly

Long-term in vivo single-cell lineage tracing of deep structures using three-photon activation

International audienceGenetic labeling techniques allow for noninvasive lineage tracing of cells in vivo. Two-photon inducible activators provide spatial resolution for superficial cells, but labeling cells located deep within tissues is precluded by scattering of the far-red illumination required for two-photon photolysis. Three-photon illumination has been shown to overcome the limitations of two-photon microscopy for in vivo imaging of deep structures, but whether it can be used for photoactivation remains to be tested. Here we show, both theoretically and experimentally, that three-photon illumination overcomes scattering problems by combining longer wavelength excitation with high uncaging three-photon cross-section molecules. We prospectively labeled heart muscle cells in zebrafish embryos and found permanent labeling in their progeny in adult animals with negligible tissue damage. This technique allows for a noninvasive genetic manipulation in vivo with spatial, temporal and cell-type specificity, and may have wide applicability in experimental biology

Sexual dimorphism in bite force in the grey mouse lemur

Sexual dimorphism is thought to be the result of sexual selection, food competition and/or niche differentiation, or simply the result of differential growth between the sexes. Despite the fact that sexual dimorphism is common among primates, lemurs are thought to be largely monomorphic. Yet, females of the species Microcebus are known to be larger than males. Here, we investigate if dimorphism in head dimensions is present in a colony of captive grey mouse lemurs Microcebus murinus. Moreover, we test whether any observed shape dimorphism is associated with differences in bite force between the sexes. Our results show that male and female grey mouse lemurs are indeed sexually dimorphic in head dimensions, with females having taller and wider heads than males. Moreover, we confirm previous observations that females are heavier than males. Bite force was principally determined by head dimensions and age in our dataset, and differed between sexes, with females biting harder than males. These data suggest a potential role for niche dimorphism in driving the observed shape and performance dimorphism as female reproductive output may depend upon the ability of animals to obtain resources that are difficult to ingest

Tridemethylisovelleral, a potent cytotoxic agent

The synthesis and in vitro cytotoxicity toward various tumor cell lines of (+/-)-tridemethylisovelleral, an analogue of the bioactive fungal sesquiterpene (+)-isovelleral retaining the bicyclo[4,1,0]hept-2-en-1,2-dicarbaidehyde system but lacking the three methyl groups, is reported. The cytotoxicity of tridemethylisovelleral toward several tumor cell lines was found to be comparable with those of established antitumor drugs, and significantly higher than that of isovelleral. (c) 2005 Elsevier Ltd. All rights reserved

Personality and performance are affected by age and early life parameters in a small primate

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