Nuage constituents arising from mitochondria: Is it possible?

An ultrastructural study of nuage-mitochondria complexes in spermatogonia of the sea urchin, Anthocidaris crassispina, was carried out. Release of mitochondrial contents into the cytoplasm was observed. The mitochondrial derivatives persisted as cristae-containing globules of friable material that subsequently contacted and integrated with nuage. The present ultrastructural findings agree with the results of other researchers who proposed that germ plasm substance probably produced by the nucleus is supplemented by the mitochondrial genome.link_to_subscribed_fulltex

Observation of Cells Not Showing Hypersensitive Reaction in the Central Part of Tobacco Mosaic Virus (TMV)-Induced Local Lesions Developing in Detached Leaves of Datura stramonium L.

It is established that the central area of TMV-induced local lesions developed in detached Datura stramonium leaves, along with the completely collapsed cells (types I and II), contains cells (type III) conserving to a certain degree integrity of their structural components. A characteristic of the type III cells was the accumulation of considerable amount of virus and formation of TMV-specific granular and tubular inclusions. The study of lesion development showed that a proportion of the collapsed cells and cells of type III did not essentially change in the period up from 3 to 5 days after infection of the leaves. These data suggest that the disease development in cells of type III does not lead to a hypersensitive response and is very similar to that in the systemically infected cells

Destruction of TMV and PVX caused by sap from the halo zones surrounding homologous virus-induced local lesions in leaves of host plants

When tobacco mosaic virus (TMV) and potato virus X (PVX) pre­pa­ra­tions were mixed with the sap from the halo zone (HZ) tissues surround­ing homologous virus-induced local lesions in Datura stramonium and Gomphrena globosa leaves, respectively, and the mixtures were incubated for 18 h at 37 °C, the virus particles underwent destruction. Under the electron microscope abnormal (swollen and “thin”) virions were observed in the incubated virus preparations negatively stained with phospho­tung­stic acid. Sometimes the TMV particles were “cut” across into fragments. Treatment of the virus preparations with the sap from the healthy leaves or HZ surrounding heterologous virus-induced local lesions may cause certain destructive changes of virus particles but to a far lesser extent than treatment with the sap from the homologous virus-induced HZ. Possible mechanisms of destruction of the virus particles are discussed

Probing metabolic alteration of differentiating induced pluripotent stem cells using label-free FLIM

The differentiation of endothelial cells from human iPSC has incontestable advantages in diseases research and therapeutic applications. However, the safe use of iPSC derivatives in regenerative medicine requires an enhanced understanding and control of factors that optimize in vitro reprogramming and differentiation protocols. Shifts in cellular metabolism associated with intracellular pH changes affect the enzymes that control epigenetic configuration, which impact chromatin reorganization and gene expression changes during reprogramming and differentiation. FLIM-based metabolic imaging of NADH and FAD is a powerful tool for measuring mitochondrial metabolic state and widely used diagnostic method for identification of neoplastic diseases, skin diseases, ocular pathologies and stem cells differentiation. Therefore, in this study, we used the potential of FLIM-based metabolic imaging and fluorescence microscopy of NADH and FAD to study the metabolic changes during iPSC differentiation in endothelial cells. The evaluation of the intracellular pH was carried out with the fluorescent pH-sensor SypHer-2 and fluorescence microscopy to obtain complete information about metabolic status of iPSC and their endothelial derivatives. Based on the FAD/NAD(P)H optical redox ratios increase and the contributions rise of the NAD(P)H fluorescence lifetime in iPSC during endothelial differentiation, we demonstrated an contribution increase of OXPHOS to cellular metabolism. Based on the shift toward more acidic intracellular pH in endothelial cell derived from iPSCs we verified their oxidative state. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only

Natural Heteroplasmy and Mitochondrial Inheritance in Bivalve Molluscs

Heteroplasmy is the presence of more than one type of mitochondrial genome within an individual, a condition commonly reported as unfavorable and affecting mitonuclear interactions. So far, no study has investigated heteroplasmy at protein level, and whether it occurs within tissues, cells, or even organelles. The only known evolutionarily stable and natural heteroplasmic system in Metazoa is the Doubly Uniparental Inheritance (DUI)-reported so far in similar to 100 bivalve species-in which two mitochondrial lineages are present: one transmitted through eggs (F-type) and the other through sperm (M-type). Because of such segregation, mitochondrial oxidative phosphorylation proteins reach a high amino acid sequence divergence (up to 52%) between the two lineages in the same species. Natural heteroplasmy coupled with high sequence divergence between F- and M-type proteins provides a unique opportunity to study their expression and assess the level and extent of heteroplasmy. Here, for the first time, we immunolocalized F- and M-type variants of three mitochondrially-encoded proteins in the DUI species Ruditapes philippinarum, in germline and somatic tissues at different developmental stages. We found heteroplasmy at organelle level in undifferentiated germ cells of both sexes, and in male soma, whereas gametes were homoplasmic: eggs for the F-type and sperm for the M-type. Thus, during gametogenesis, only the sex-specific mitochondrial variant is maintained, likely due to a process of meiotic drive. We examine the implications of our results for DUI proposing a revised model, and we discuss interactions of mitochondria with germ plasm and their role in germline development. Molecular and phylogenetic evidence suggests that DUI evolved from the common Strictly Maternal Inheritance, so the two systems likely share the same underlying molecular mechanism, making DUI a useful system for studying mitochondrial biology

Label-free sorting of iPS cells during neuronal differentiation using FLIM and multiphoton fluorescence microscopy

The changes in cell metabolism can affect the epigenome-modifying enzymes activity during iPSCs differentiation and thus control the functional potential of the final cell. Therefore, for therapeutic applications, the restoration of a fully functional mitochondrial network specific for the cell types derived from iPSCs will be required to support the energy and other mitochondrial factors. Recently, FLIM method allows to study the metabolic changes that accompanying cell differentiation noninvasively and without additional labels. In this study, we investigated the metabolic changes in iPSCs during neural differentiation using two-photon fluorescence microscopy and FLIM. Cellular metabolism was examined by monitoring the optical redox ratio (FAD/NAD(P)H), the fluorescence lifetime contributions of the free and bound forms of NADH and NADPH. Given that neural differentiation is also accompanied by synthetic proceßes and oxidative streß, this proceß was included in the scope of this work. We demonstrated an increased contribution of protein-bound NADH and NADPH in neuron aßociated with metabolic switch to oxidative phosphorylation and the biosynthetic proceßes or oxidative streß, respectively. We also found that the optical redox ratio FAD/NAD(P)H decreased during neural differentiation, and this was likely to be explained by the intensive lipid membrane synthesis or ROS generating and the enhanced NADPH production aßociated with them. The biochemical analysis was carried out to verify the metabolic status of iPSCs and their neural derivatives. Based on the data on glucose consumption, lactate and ATP amount we registered the trend to the metabolic pathways redistribution towards the oxidative phosphorylation in neuron. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only