Electron Microscopy of the Amphibian Model Systems Xenopus laevis and Ambystoma mexicanum

Kurth, Thomas; Berger, Jürgen; Wilsch‐Bräuninger, Michaela; Kretschmar, Susanne; Cerny, Robert; Schwarz, Heinz; Löfberg, Jan; Piendl, Thomas; Epperlein, Hans‐Henning

doi:10.1016/s0091-679x(10)96017-2

Cited by 27 publications

(23 citation statements)

References 95 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For semi-thin sections and electron microscopy, zebrafish hearts were fixed in modified Karnovsky's fixative (2% glutaraldehyde +2% paraformaldehyde in 50 mM HEPES, [27], [28]) at 4°C overnight, and washed 2x in 100 mM HEPES and 2x in PBS. For light microscopy the samples were embedded in the methacrylate Technovit 7100 (Heraeus-Kulzer).…”

Section: Methodsmentioning

confidence: 99%

Regeneration of Cryoinjury Induced Necrotic Heart Lesions in Zebrafish Is Associated with Epicardial Activation and Cardiomyocyte Proliferation

et al. 2011

Self Cite

View full text Add to dashboard Cite

In mammals, myocardial cell death due to infarction results in scar formation and little regenerative response. In contrast, zebrafish have a high capacity to regenerate the heart after surgical resection of myocardial tissue. However, whether zebrafish can also regenerate lesions caused by cell death has not been tested. Here, we present a simple method for induction of necrotic lesions in the adult zebrafish heart based on cryoinjury. Despite widespread tissue death and loss of cardiomyocytes caused by these lesions, zebrafish display a robust regenerative response, which results in substantial clearing of the necrotic tissue and little scar formation. The cellular mechanisms underlying regeneration appear to be similar to those activated in response to ventricular resection. In particular, the epicardium activates a developmental gene program, proliferates and covers the lesion. Concomitantly, mature uninjured cardiomyocytes become proliferative and invade the lesion. Our injury model will be a useful tool to study the molecular mechanisms of natural heart regeneration in response to necrotic cell death.

show abstract

Section: Methodsmentioning

confidence: 99%

Regeneration of Cryoinjury Induced Necrotic Heart Lesions in Zebrafish Is Associated with Epicardial Activation and Cardiomyocyte Proliferation

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…Immunogold labeling was performed as described (Kurth et al, 2010; see Appendix and Table 1), and samples analyzed on a Morgagni D268 (FEI) or a JEM1400 Plus (JEOL) at 80 kV acceleration voltage.…”

Section: Electron Microscopymentioning

confidence: 99%

An increase in neural stem cells and olfactory bulb adult neurogenesis improves discrimination of highly similar odorants

et al. 2019

View full text Add to dashboard Cite

Adult neurogenesis is involved in cognitive performance but studies that manipulated this process to improve brain function are scarce. Here, we characterized a genetic mouse model in which neural stem cells (NSC) of the subventricular zone (SVZ) were temporarily expanded by conditional expression of the cell cycle regulators Cdk4/cyclinD1, thus increasing neurogenesis. We found that supernumerary neurons matured and integrated in the olfactory bulb similarly to physiologically generated newborn neurons displaying a correct expression of molecular markers, morphology and electrophysiological activity. Olfactory performance upon increased neurogenesis was unchanged when mice were tested on relatively easy tasks using distinct odor stimuli. In contrast, intriguingly, increasing neurogenesis improved the discrimination ability of mice when challenged with a difficult task using mixtures of highly similar odorants. Together, our study provides a mammalian model to control the expansion of somatic stem cells that can in principle be applied to any tissue for basic research and models of therapy. By applying this to NSC of the SVZ, we highlighted the importance of adult neurogenesis to specifically improve performance in a challenging olfactory task.

show abstract

“…Actin dynamics were viewed in LifeAct mRNA-injected cells using a Carl Zeiss LSM 510 confocal microscope. For transmission electron microscopy, gastrula explants were fixed in 2.5% glutaraldehyde/2% formaldehyde, post-fixed with 1% osmium tetraoxide and infiltrated with Spurr's resin as described (Kurth et al, 2010). Ultrathin sections were stained with uranyl acetate and post-stained with Reynold's lead citrate.…”

Section: Microscopymentioning

confidence: 99%

Tissue cohesion and the mechanics of cell rearrangement

et al. 2014

View full text Add to dashboard Cite

Morphogenetic processes often involve the rapid rearrangement of cells held together by mutual adhesion. The dynamic nature of this adhesion endows tissues with liquid-like properties, such that largescale shape changes appear as tissue flows. Generally, the resistance to flow (tissue viscosity) is expected to depend on the cohesion of a tissue (how strongly its cells adhere to each other), but the exact relationship between these parameters is not known. Here, we analyse the link between cohesion and viscosity to uncover basic mechanical principles of cell rearrangement. We show that for vertebrate and invertebrate tissues, viscosity varies in proportion to cohesion over a 200-fold range of values. We demonstrate that this proportionality is predicted by a cell-based model of tissue viscosity. To do so, we analyse cell adhesion in Xenopus embryonic tissues and determine a number of parameters, including tissue surface tension (as a measure of cohesion), cell contact fluctuation and cortical tension. In the tissues studied, the ratio of surface tension to viscosity, which has the dimension of a velocity, is 1.8 µm/min. This characteristic velocity reflects the rate of cell-cell boundary contraction during rearrangement, and sets a limit to rearrangement rates. Moreover, we propose that, in these tissues, cell movement is maximally efficient. Our approach to cell rearrangement mechanics links adhesion to the resistance of a tissue to plastic deformation, identifies the characteristic velocity of the process, and provides a basis for the comparison of tissues with mechanical properties that may vary by orders of magnitude.

show abstract

Electron Microscopy of the Amphibian Model Systems Xenopus laevis and Ambystoma mexicanum

Cited by 27 publications

References 95 publications

Regeneration of Cryoinjury Induced Necrotic Heart Lesions in Zebrafish Is Associated with Epicardial Activation and Cardiomyocyte Proliferation

Regeneration of Cryoinjury Induced Necrotic Heart Lesions in Zebrafish Is Associated with Epicardial Activation and Cardiomyocyte Proliferation

An increase in neural stem cells and olfactory bulb adult neurogenesis improves discrimination of highly similar odorants

Tissue cohesion and the mechanics of cell rearrangement

Contact Info

Product

Resources

About