Caspase-2 is upregulated after sciatic nerve transection and its inhibition protects dorsal root ganglion neurons from Apoptosis after serum withdrawal

Sciatic nerve (SN) transection-induced apoptosis of dorsal root ganglion neurons (DRGN) is one factor determining the efficacy of peripheral axonal regeneration and the return of sensation. Here, we tested the hypothesis that caspase-2(CASP2) orchestrates apoptosis of axotomised DRGN both in vivo and in vitro by disrupting the local neurotrophic supply to DRGN. We observed significantly elevated levels of cleaved CASP2 (C-CASP2), compared to cleaved caspase-3 (C-CASP3), within TUNEL+DRGN and DRG glia (satellite and Schwann cells) after SN transection. A serum withdrawal cell culture model, which induced 40% apoptotic death in DRGN and 60% in glia, was used to model DRGN loss after neurotrophic factor withdrawal. Elevated C-CASP2 and TUNEL were observed in both DRGN and DRG glia, with C-CASP2 localisation shifting from the cytosol to the nucleus, a required step for induction of direct CASP2-mediated apoptosis. Furthermore, siRNAmediated downregulation of CASP2 protected 50% of DRGN from apoptosis after serum withdrawal, while downregulation of CASP3 had no effect on DRGN or DRG glia survival. We conclude that CASP2 orchestrates the death of SN-axotomised DRGN directly and also indirectly through loss of DRG glia and their local neurotrophic factor support. Accordingly, inhibiting CASP2 expression is a potential therapy for improving both the SN regeneration response and peripheral sensory recovery

Eukaryote DIRS1-like retrotransposons: an overview

<p>Abstract</p> <p>Background</p> <p>DIRS1-like elements compose one superfamily of tyrosine recombinase-encoding retrotransposons. They have been previously reported in only a few diverse eukaryote species, describing a patchy distribution, and little is known about their origin and dynamics. Recently, we have shown that these retrotransposons are common among decapods, which calls into question the distribution of DIRS1-like retrotransposons among eukaryotes.</p> <p>Results</p> <p>To determine the distribution of DIRS1-like retrotransposons, we developed a new computational tool, ReDoSt, which allows us to identify well-conserved DIRS1-like elements. By screening 274 completely sequenced genomes, we identified more than 4000 DIRS1-like copies distributed among 30 diverse species which can be clustered into roughly 300 families. While the diversity in most species appears restricted to a low copy number, a few bursts of transposition are strongly suggested in certain species, such as <it>Danio rerio </it>and <it>Saccoglossus kowalevskii</it>.</p> <p>Conclusion</p> <p>In this study, we report 14 new species and 8 new higher taxa that were not previously known to harbor DIRS1-like retrotransposons. Now reported in 61 species, these elements appear widely distributed among eukaryotes, even if they remain undetected in streptophytes and mammals. Especially in unikonts, a broad range of taxa from Cnidaria to Sauropsida harbors such elements. Both the distribution and the similarities between the DIRS1-like element phylogeny and conventional phylogenies of the host species suggest that DIRS1-like retrotransposons emerged early during the radiation of eukaryotes.</p

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Not AvailableSymbiotic (Rhizobia, Frankia, and VAM) or free-living (Azotobacter, and Clostridium) association of plant growth-promoting rhizobacteria (PGPR) and fungi (PGPF) is essential for plant and soil health. Nitrogen (N), phosphorus (P) and potassium (K) as major and iron (Fe) and zinc (Zn) as the minor elements are key to plant health. They are important constituents of plant genetic material (N, P) and chlorophyll content (N, Fe) and important for enzymatic activities (Fe, Zn) and are involved in many biochemical and physiological activities. The ‘microbiome’ around the rhizosphere is specific to plant type and involved in nutrient cycling through various processes such as fixation (N), solubilization, mineralization (P, K) and uptake, with the help of various organic acids (gluconic acid, oxalic acid, and tartaric acid), siderophore activity (Fe uptake) and enzymatic actions (nitrogenase, phytases, and acid phosphatases). Phytohormones essential to plant growth and development are produced by microbes themselves or induce their production via other hormones or communication chemicals, viz., volatile organic compounds (VOCs) like 2-pentylfuran, 2,3-butanediol and acetonin. PGPR (Pseudomonas, Trichoderma and Streptomyces) helps the host plant to fight against various abiotic and biotic stresses by the release of bactericidal and fungicidal enzymes, metabolite accumulation and induced systemic resistance (ISR), systemic acquired resistance (SAR) by phytohormones (jasmonic acid, salicylic acid, and ethylene) and VOCs. Attributing to so many benefits, microbes are increasingly becoming part of sustainable agriculture where PGPR (Rhizobium and Pseudomonas) and fungi (Aspergillus, Trichoderma and VAM) are being used as biofertilizers either single strained or in consortia approach, where the latter is found to be more beneficial for plant and soil health.Not Availabl