Peroxiredoxin5 controls vertebrate ciliogenesis by modulating mitochondrial ROS

Aims: Peroxiredoxin5 (Prdx5) - a thioredoxin peroxidase is an antioxidant enzyme that is widely studied for its antioxidant properties and protective roles in neurological and cardiovascular disorders. The present study is aimed to investigate the functional significance of Prdx5 in mitochondria and to analyze its roles in ciliogenesis during the process of vertebrate development. Results: We found that several Prdx genes were strongly expressed in multiciliated cells in developing Xenopus embryos, and their peroxidatic functions were crucial for normal cilia development. Depletion of Prdx5 increased levels of cellular ROS, consequently leading to mitochondrial dysfunction and abnormal cilia formation. Proteomic and transcriptomic approaches revealed that excessive ROS accumulation upon Prdx5 depletion subsequently reduced the expression level of pyruvate kinase (PK), a key metabolic enzyme in energy production. We further confirmed that the promotor activity of PK was significantly reduced upon Prdx5 depletion and that the reduction in PK expression and its promoter activity led to ciliary defects observed in Prdx5-depleted cells. Innovation: Our data revealed the novel relationship between ROS and Prdx5 and the consequent effects of this interaction on vertebrate ciliogenesis. The normal process of ciliogenesis is interrupted by the Prdx5 depletion resulting in excessive ROS levels suggesting cilia as vulnerable targets of ROS. Conclusion: Prdx5 play protective roles in mitochondria and is critical for normal cilia development by regulating the levels of ROS. The loss of Prdx5 is associated with excessive production of ROS resulting in mitochondrial dysfunction and aberrant ciliogenesis

Boron And Carbon Cosmic rays in the Upper Stratosphere (BACCUS)

International audienceThe balloon-borne BACCUS experiment measures directly the elemental spectra of cosmic-ray nuclei from protons to Fe over the energy range ~10^12 to 10^15 eV. It focuses on the energy dependence of secondary to primary ratios (e.g. B/C) to investigate cosmic-ray propagation history. BACCUS consists of redundant and complementary particle detectors including the Timing Charge Detector (TCD), Transition Radiation Detector (TRD), Cherenkov Detector (CD), Silicon Charge Detector (SCD), and Calorimeter (CAL). The TCD measures the light yield produced by the particle in plastic scintillator. The TRD provides energy measurements of incident 3 ≤ Z ≤ 26 nuclei in the 102 – 105 Lorentz factor range. The CD responds only to particles with velocity exceeding the velocity of light in the plastic. It allows BACCUS to reject the abundant low energy cosmic rays present in the polar region. The CAL is used to determine the particle’s energy for all nuclei for 1 ≤ Z ≤ 26. With the SCD based on pixellation, in addition to the TCD based on timing, and the CD, the BACCUS instrument implements virtually all possible techniques to minimize the effect of backscatter on charge measurements in the presence of a large particle shower in the CAL. The 30 day flight was carried out successfully over Antarctica in 2016 from Nov. 28 to Dec. 28. The integration test, and performance of instruments will be presented

The complete mitochondrial genome of the Indian leafwing butterfly Kallima paralekta (insecta: Lepidoptera: Nymphalidae)

The Indian leafwing butterfly Kallima paralekta (Horsfield, 1829) (Nymphalidae) is an Asian forest-dwelling, leaf-mimic. Genome skimming by Illumina sequencing permitted assembly of a complete circular mitogenome of 15,200 bp from K. paralekta consisting of 79.5% AT nucleotides, 22 tRNAs, 13 protein-coding genes, two rRNAs and a control region in the typical butterfly gene order. Kallima paralekta COX1 features an atypical CGA start codon, while ATP6, COX1, COX2, ND4, ND4L, and ND5 exhibit incomplete stop codons completed by 3’ A residues added to the mRNA. Phylogenetic reconstruction places K. paraleckta within the monophyletic genus Kallima, sister to Mallika in the subfamily Nymphalinae. These data support the monophyly of tribe Kallimini and contribute to the evolutionary systematics of the Nymphalidae