The Complete Mitochondrial Genome of Two Armored Catfish Populations of the Genus Hypostomus (Siluriformes, Loricariidae, Hypostominae)

Hypostomus Lacépède (1803) is the dominant genus of armored catfish (Siluriformes, Loricariidae, Hypostominae) in Brazilian rivers (Britski, 1972). This group presents a wide interspecific color and morphology variation (Oyakawa et al., 2005), which hinders the identification of some species. Likewise, the existence of various cytogenetic phenotypes, including different chromosomal numbers, karyotype formulas, and location of ribosomal genes (Rocha-Reis et al., 2020), reinforces the need for more appropriate methodologies for species identification

Functional and Evolutionary Characterization of a UDP-Xylose Synthase Gene from the Plant Pathogen <i>Xylella fastidiosa</i>, Involved in the Synthesis of Bacterial Lipopolysaccharide

<i>Xylella fastidiosa</i> is a plant-infecting bacillus, responsible for many important crop diseases, such as Pierce’s disease of vineyards, citrus variegated chlorosis, and coffee leaf scorch (CLS), among others. Recent genomic comparisons involving two CLS-related strains, belonging to <i>X. fastidiosa</i> subsp. <i>pauca</i>, revealed that one of them carries a frameshift mutation that inactivates a gene encoding an oxidoreductase of the short-chain dehydrogenase/reductase (SDR) superfamily, which may play important roles in determining structural variations in bacterial glycans and glycoconjugates. However, the exact nature of this SDR has been a matter of controversy, as different annotations of <i>X. fastidiosa</i> genomes have implicated it in distinct reactions. To confirm the nature of this mutated SDR, a comparative analysis was initially performed, suggesting that it belongs to a subgroup of SDR decarboxylases, representing a UDP-xylose synthase (Uxs). Functional assays, using a recombinant derivative of this enzyme, confirmed its nature as <i>Xf</i>Uxs, and carbohydrate composition analyses, performed with lipopolysaccharide (LPS) molecules obtained from different strains, indicate that inactivation of the <i>X. fastidiosa uxs</i> gene affects the LPS structure among CLS-related <i>X. fastidiosa</i> strains. Finally, a comparative sequence analysis suggests that this mutation is likely to result in a morphological and evolutionary hallmark that differentiates two subgroups of CLS-related strains, which may influence interactions between these bacteria and their plant and/or insect hosts

Functional and Evolutionary Characterization of a UDP-Xylose Synthase Gene from the Plant Pathogen <i>Xylella fastidiosa</i>, Involved in the Synthesis of Bacterial Lipopolysaccharide

<i>Xylella fastidiosa</i> is a plant-infecting bacillus, responsible for many important crop diseases, such as Pierce’s disease of vineyards, citrus variegated chlorosis, and coffee leaf scorch (CLS), among others. Recent genomic comparisons involving two CLS-related strains, belonging to <i>X. fastidiosa</i> subsp. <i>pauca</i>, revealed that one of them carries a frameshift mutation that inactivates a gene encoding an oxidoreductase of the short-chain dehydrogenase/reductase (SDR) superfamily, which may play important roles in determining structural variations in bacterial glycans and glycoconjugates. However, the exact nature of this SDR has been a matter of controversy, as different annotations of <i>X. fastidiosa</i> genomes have implicated it in distinct reactions. To confirm the nature of this mutated SDR, a comparative analysis was initially performed, suggesting that it belongs to a subgroup of SDR decarboxylases, representing a UDP-xylose synthase (Uxs). Functional assays, using a recombinant derivative of this enzyme, confirmed its nature as <i>Xf</i>Uxs, and carbohydrate composition analyses, performed with lipopolysaccharide (LPS) molecules obtained from different strains, indicate that inactivation of the <i>X. fastidiosa uxs</i> gene affects the LPS structure among CLS-related <i>X. fastidiosa</i> strains. Finally, a comparative sequence analysis suggests that this mutation is likely to result in a morphological and evolutionary hallmark that differentiates two subgroups of CLS-related strains, which may influence interactions between these bacteria and their plant and/or insect hosts