A systems biology approach reveals neuronal and muscle developmental defects after chronic exposure to ionising radiation in zebrafish.

Contamination of the environment after the Chernobyl and Fukushima Daiichi nuclear power plant (NPP) disasters led to the exposure of a large number of humans and wild animals to radioactive substances. However, the sub-lethal consequences induced by these absorbed radiological doses remain understudied and the long-term biological impacts largely unknown. We assessed the biological effects of chronic exposure to ionizing radiation (IR) on embryonic development by exposing zebrafish embryo from fertilization and up to 120 hours post-fertilization (hpf) at dose rates of 0.

Effects of tritiated water on locomotion of zebrafish larvae: a new insight in tritium toxic effects on a vertebrate model species.

Tritium (H), a radioactive isotope of hydrogen, is ubiquitously present in the environment. In a previous study, we highlighted a mis-regulation of genes involved in muscle contraction, eye transparency and response to DNA damages after exposure of zebrafish embryo-larvae from 3 hpf to 96 hpf at 0.4 and 4 mGy/h of tritiated water (HTO).

Chloroplast-Specific in Vivo Ca2+ Imaging Using Yellow Cameleon Fluorescent Protein Sensors Reveals Organelle-Autonomous Ca2+ Signatures in the Stroma.

In eukaryotes, subcellular compartments such as mitochondria, the endoplasmic reticulum, lysosomes, and vacuoles have the capacity for Ca(2+) transport across their membranes to modulate the activity of compartmentalized enzymes or to convey specific cellular signaling events. In plants, it has been suggested that chloroplasts also display Ca(2+) regulation. So far, monitoring of stromal Ca(2+) dynamics in vivo has exclusively relied on using the luminescent Ca(2+) probe aequorin.

Analyses of Ca2+ accumulation and dynamics in the endoplasmic reticulum of Arabidopsis root cells using a genetically encoded Cameleon sensor.

In planta, very limited information is available about how the endoplasmic reticulum (ER) contributes to cellular Ca(2+) dynamics and homeostasis. Here, we report the generation of an ER-targeted Cameleon reporter protein suitable for analysis of Ca(2+) accumulation and dynamics in the lumen of the ER in plant cells. Using stably transformed Arabidopsis (Arabidopsis thaliana) plants expressing this reporter protein, we observed a transiently enhanced accumulation of Ca(2+) in the ER in response to stimuli inducing cytosolic Ca(2+) rises in root tip cells.

Imaging of mitochondrial and nuclear Ca2+ dynamics in Arabidopsis roots.

Here we report a method for analyzing mitochondrial Ca(2+) dynamics in plant root cells by means of the newly generated cameleon probe 4mt-YC3.6. The use of plants expressing both nuclear- and mitochondrial-targeted cameleon, along with the resolution of confocal laser scanning microscopy (CLSM), allow simultaneous recordings of mitochondrial and nuclear Ca(2+) dynamics within the same cell.

Ca2+ imaging in plants using genetically encoded Yellow Cameleon Ca2+ indicators.

Temporally and spatially defined changes in cellular calcium (Ca(2+)) concentration represent stimulus-specific signals and regulate a myriad of biological processes. The development of ratiometric Ca(2+) reporter proteins like Yellow Cameleons (YCs) has greatly advanced our ability to analyze Ca(2+) dynamics in vivo with unprecedented spatial and temporal resolution. In plants, the application of these Ca(2+) reporter proteins has been pioneered for the investigation of Ca(2+) dynamics in guard cells, and recently their use has been extended to other single-cell models like growing pollen tubes and root hairs.

Targeting of Cameleons to various subcellular compartments reveals a strict cytoplasmic/mitochondrial Ca²⁺ handling relationship in plant cells.

Here we describe use of a mitochondrial targeted Cameleon to produce stably transformed Arabidopsis plants that enable analyses of mitochondrial Ca²⁺ dynamics in planta and allow monitoring of the intra-mitochondrial Ca²⁺ concentration in response to physiological or environmental stimuli. Transgenic plants co-expressing nuclear and mitochondrial targeted Cameleons were also generated and analyzed. Here we show that mitochondrial Ca²⁺ accumulation is strictly related to the intensity of the cytoplasmic Ca²⁺ increase, demonstrating a tight association between mitochondrial and cytoplasmic Ca²⁺ dynamics.