The first observed stellar occultations by the irregular satellite Phoebe (Saturn IX) and improved rotational period

peer reviewedWe report six stellar occultations by Phoebe (Saturn IX), an irregular satellite of Saturn, obtained between mid-2017 and mid-2019. The 2017 July 6 event was the first stellar occultation by an irregular satellite ever observed. The occultation chords were compared to a 3D shape model of the satellite obtained from Cassini observations. The rotation period available in the literature led to a sub-observer point at the moment of the observed occultations where the chords could not fit the 3D model. A procedure was developed to identify the correct sub-observer longitude. It allowed us to obtain the rotation period with improved precision compared to the currently known value from literature. We show that the difference between the observed and the predicted sub-observer longitude suggests two possible solutions for the rotation period. By comparing these values with recently observed rotational light curves and single- chord stellar occultations, we can identify the best solution for Phoebe's rotational period as 9.27365 ± 0.00002 h. From the stellar occultations, we also obtained six geocentric astrometric positions in the ICRS as realized by the Gaia DR2 with uncertainties at the 1-mas level

Novel deletion alleles carrying CYP21A1P/A2 chimeric genes in Brazilian patients with 21-hydroxylase deficiency

<p>Abstract</p> <p>Background</p> <p>Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is caused by deletions, large gene conversions or mutations in <it>CYP21A2 </it>gene. The human gene is located at 6p21.3 within a <it>locus </it>containing the genes for putative serine/threonine Kinase <it>RP</it>, complement <it>C4</it>, steroid 21-hydroxylase <it>CYP21 </it>tenascin <it>TNX</it>, normally, in a duplicated cluster known as RCCX module. The <it>CYP21 </it>extra copy is a pseudogene (<it>CYP21A1P</it>). In Brazil, 30-kb deletion forming monomodular alleles that carry chimeric <it>CYP21A1P/A2 </it>genes corresponds to ~9% of disease-causing alleles. Such alleles are considered to result from unequal crossovers within the bimodular <it>C4/CYP21 locus</it>. Depending on the localization of recombination breakpoint, different alleles can be generated conferring the locus high degree of allelic variability. The purpose of the study was to investigate the variability of deleted alleles in patients with 21-hydroxylase deficiency.</p> <p>Methods</p> <p>We used different techniques to investigate the variability of 30-kb deletion alleles in patients with 21-hydroxylase deficiency. Alleles were first selected after Southern blotting. The composition of <it>CYP21A1P/A2 </it>chimeric genes was investigated by ASO-PCR and MLPA analyses followed by sequencing to refine the location of recombination breakpoints. Twenty patients carrying at least one allele with <it>C4/CYP21 </it>30-kb deletion were included in the study.</p> <p>Results</p> <p>An allele carrying a <it>CYP21A1P/A2 </it>chimeric gene was found unusually associated to a <it>C4B/C4A </it><it>Taq </it>I 6.4-kb fragment, generally associated to <it>C4B </it>and <it>CYP21A1P </it>deletions. A novel haplotype bearing both p.P34L and p.H62L, novel and rare mutations, respectively, was identified in exon 1, however p.P30L, the most frequent pseudogene-derived mutation in this exon, was absent. Four unrelated patients showed this haplotype. Absence of p.P34L in <it>CYP21A1P </it>of normal controls indicated that it is not derived from pseudogene. In addition, the combination of different approaches revealed nine haplotypes for deleted 21-hydroxylase deficiency alleles.</p> <p>Conclusions</p> <p>This study demonstrated high allelic variability for 30-kb deletion in patients with 21-hydroxylase deficiency indicating that a founder effect might be improbable for most monomodular alleles carrying <it>CYP21A1P/A2 </it>chimeric genes in Brazil.</p

Clinical oxidative stress during leprosy multidrug therapy:impact of dapsone oxidation

This study aims to assess the oxidative stress in leprosy patients under multidrug therapy (MDT; dapsone, clofazimine and rifampicin), evaluating the nitric oxide (NO) concentration, catalase (CAT) and superoxide dismutase (SOD) activities, glutathione (GSH) levels, total antioxidant capacity, lipid peroxidation, and methemoglobin formation. For this, we analyzed 23 leprosy patients and 20 healthy individuals from the Amazon region, Brazil, aged between 20 and 45 years. Blood sampling enabled the evaluation of leprosy patients prior to starting multidrug therapy (called MDT 0) and until the third month of multidrug therapy (MDT 3). With regard to dapsone (DDS) plasma levels, we showed that there was no statistical difference in drug plasma levels between multibacillary (0.518±0.029 μg/mL) and paucibacillary (0.662±0.123 μg/mL) patients. The methemoglobin levels and numbers of Heinz bodies were significantly enhanced after the third MDTsupervised dose, but this treatment did not significantly change the lipid peroxidation and NO levels in these leprosy patients. In addition, CAT activity was significantly reduced in MDT-treated leprosy patients, while GSH content was increased in these patients. However, SOD and Trolox equivalent antioxidant capacity levels were similar in patients with and without treatment. These data suggest that MDT can reduce the activity of some antioxidant enzyme and influence ROS accumulation, which may induce hematological changes, such as methemoglobinemia in patients with leprosy. We also explored some redox mechanisms associated with DDS and its main oxidative metabolite DDS-NHOH and we explored the possible binding of DDS to the active site of CYP2C19 with the aid of molecular modeling software

Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii

Background: Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. Results: We have sequenced the genomes of strains B and C to draft status. We have compared their genomic content to X. citri subsp. citri and to other Xanthomonas genomes, with special emphasis on type III secreted effector repertoires. In addition to pthA, already known to be present in all three citrus canker strains, two additional effector genes, xopE3 and xopAI, are also present in all three strains and are both located on the same putative genomic island. These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. Numerous gene content differences also exist between the three cankers strains, which can be correlated with their different virulence and host range. Particular attention was placed on the analysis of genes involved in biofilm formation and quorum sensing, type IV secretion, flagellum synthesis and motility, lipopolysacharide synthesis, and on the gene xacPNP, which codes for a natriuretic protein. Conclusion: We have uncovered numerous commonalities and differences in gene content between the genomes of the pathogenic agents causing citrus canker A, B, and C and other Xanthomonas genomes. Molecular genetics can now be employed to determine the role of these genes in plant-microbe interactions. The gained knowledge will be instrumental for improving citrus canker control.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientIfico e Tecnologico (CNPq)Coordenacao para Aperfeicoamento de Pessoal de Ensino Superior (CAPES)Fundo de Defesa da Citricultura (FUNDECITRUS