Novel nontoxic mitochondrial probe for confocal fluorescence microscopy.

We propose a 2,5-Bis[1-(4-N-methylpyridinium)ethen-2-yl)]-N-methylpyrrole ditriflate (PEPEP) as a novel nontoxic, nonpotentiometric mitochondrial probe for confocal fluorescence microscopy. PEPEP is a representative chromophore of a large family of heterocyclic fluorescent dyes that show fluorescence emission in aqueous media and great DNA affinity. We check its cytotoxicity and intracellular localization in mammalian and yeast cell cultures. We demonstrate that PEPEP is a very efficient dye for fluorescence confocal microscopy and a valuable alternative to the most frequently used mitochondrial stains. © 2006 Society of Photo-Optical Instrumentation Engineers

Effects of microgravity simulation on zebrafish transcriptomes and bone physiology; exposure starting at 5 days post-fertilization.

Physiological modifications in near weightlessness, as experienced by astronauts during space flight, have been the subject of numerous studies. Various animal models have been used on space missions or in microgravity simulation on ground to understand the effects of gravity on living animals. Here, we used the zebrafish larvae as a model to study the effect of microgravity simulation on bone formation and whole genome gene expression. To simulate microgravity (sim-mu g), we used two-dimensional (2D) clinorotation starting at 5 days post fertilization to assess skeletal formation after 5 days of treatment. To assess early, regulatory effects on gene expression, a single day clinorotation was performed. Clinorotation for 5 days caused a significant decrease of bone formation, as shown by staining for cartilage and bone structures. This effect was not due to stress, as assessed by measuring cortisol levels in treated larvae. Gene expression results indicate that 1-day simulated microgravity affected musculoskeletal, cardiovascular, and nuclear receptor systems. With free-swimming model organisms such as zebrafish larvae, the 2D clinorotation setup appears to be a very appropriate approach to sim-mu g. We provide evidence for alterations in bone formation and other important biological functions; in addition several affected genes and pathways involved in bone, muscle or cardiovascular development are identified