Alterations on cellular redox states upon infection and implications for host cell homeostasis

The cofactors nicotinamide adenine dinucleotide (NAD+) and its phosphate form, NADP+, are crucial molecules present in all living cells. The delicate balance between the oxidized and reduced forms of these molecules is tightly regulated by intracellular metabolism assuring the maintenance of homeostatic conditions, which are essential for cell survival and proliferation. A recent cluster of data has highlighted the importance of the intracellular NAD+/NADH and NADP+/NADPH ratios during host-pathogen interactions, as fluctuations in the levels of these cofactors and in precursors' bioavailability may condition host response and, therefore, pathogen persistence or elimination. Furthermore, an increasing interest has been given towards how pathogens are capable of hijacking host cell proteins in their own advantage and, consequently, alter cellular redox states and immune function. Here, we review the basic principles behind biosynthesis and subcellular compartmentalization of NAD+ and NADP+, as well as the importance of these cofactors during infection, with a special emphasis on pathogen-driven modulation of host NAD+/NADP+ levels and contribution to the associated immune response.(undefined)info:eu-repo/semantics/publishedVersio

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu