The mitochondrial permeability transition (mPT) is increasingly implicated in neuronal cell death. In the present study, isolated respiring brain mitochondria were examined for their ability to undergo calcium-induced mPT and their sensitivity to mPT inhibition by cyclosporin A (CsA). Previous studies have suggested a heterogeneous response to calcium, a limitation of CsA inhibition, and a relative resistance in the ability of respiring brain mitochondria to undergo mPT. Using fluorometric and electron microscopic analyses, we found that virtually the whole population of respiring brain mitochondria readily undergo mPT and swell upon calcium exposure. Further, brain mitochondria were highly sensitive to CsA which potentiated morphological recovery after transient swelling as well as completely blocked mPT induction in the presence of a low concentration of ADP. Using flow cytometry, which allows analysis of individual mitochondria, we demonstrate that both brain and liver mitochondria display homogeneous responses to calcium-induced mPT. We conclude that the mPT is one likely target for the broad in vivo neuroprotective effects displayed by CsA when allowed to penetrate the blood-brain barrier, and that development of compounds inhibiting mPT may prove beneficial for the treatment of severe brain disease.

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Background Salix spp. are high-productivity crops potentially used for lignocellulosic biofuels such as bioethanol. In general, pretreatment is needed to facilitate the enzymatic depolymerization process. Biomass resistance to degradation, i.e., biomass recalcitrance , is a trait which can be assessed by measuring the sugar released after combined pretreatment and enzymatic hydrolysis. We have examined genetic parameters of enzymatic sugar release and other traits related to biorefinery use in a population of 286 natural Salix viminalis clones. Furthermore, we have evaluated phenotypic and genetic correlations between these traits and performed a genomewide association mapping analysis using a set of 19,411 markers. Results Sugar release (glucose and xylose) after pretreatment and enzymatic saccharification proved highly variable with large genetic and phenotypic variations, and chip heritability estimates ( h 2 ) of 0.23–0.29. Lignin syringyl/guaiacyl (S/G) ratio and wood density were the most heritable traits ( h 2 = 0.42 and 0.59, respectively). Sugar release traits were positively correlated, phenotypically and genetically, with biomass yield and lignin S/G ratio. Association mapping revealed seven marker–trait associations below a suggestive significance threshold, including one marker associated with glucose release. Conclusions We identified lignin S/G ratio and shoot diameter as heritable traits that could be relatively easily evaluated by breeders, making them suitable proxy traits for developing low-recalcitrance varieties. One marker below the suggestive threshold for marker associations was identified for sugar release, meriting further investigation while also highlighting the difficulties in employing genomewide association mapping for complex traits. Electronic supplementary material The online version of this article (10.1186/s13068-019-1479-7) contains supplementary material, which is available to authorized users.

Autophagy is a major catabolic process in eukaryotes with a key role in homeostasis, programmed cell death, and aging. In plants, autophagy is also known to regulate agronomically important traits such as stress resistance, longevity, vegetative biomass, and seed yield. Despite its significance, there is still a shortage of reliable tools modulating plant autophagy. Here, we describe the first robust pipeline for identification of specific plant autophagy-modulating compounds. Our screening protocol comprises four phases: (1) high-throughput screening of chemical compounds in cell cultures of tobacco (Nicotiana tabacum); (2) confirmation of the identified hits in planta using Arabidopsis (Arabidopsis thaliana); (3) further characterization of the effect using conventional molecular biology methods; and (4) verification of chemical specificity on autophagy in planta. The methods detailed here streamline the identification of specific plant autophagy modulators and aid in unraveling the molecular mechanisms of plant autophagy.