Mitochondrion genomes of seven species of the endangered genus Sporophila (Passeriformes: Thraupidae).

We announce the mitochondrial genomes of seven species of the genus Sporophila (S. bouvreuil, S. iberaensis, S. melanogaster, S. minuta, S. nigrorufa, S. pileata, and S. ruficollis) which were validated by comparative genomic and phylogenetic analysis with related species. The mitochondrial genomes of seven passerines of the genus Sporophila were assembled (three complete and four nearly complete genomes) and were validated by reconstructing phylogenetic relations within Thraupidae. The complete mitogenomes ranged from 16,781 bp in S. ruficollis to 16,791 bp in S. minuta. We identified a conserved genome composition within all mitogenomes with 13 protein-coding genes, 22 tRNAs and two rRNAs. We observed a bias in the nucleotide composition and six mutational hotspots in Sporophila mitogenomes. Our mitogenome-based phylogenetic tree has S. minuta, S. maximiliani and S. nigricollis as sister species of the remaining species in the genus. We present new mitogenome sequences for seven Sporophila species, providing new genomic resources that may be useful for research on the evolution, comparative genetics, and conservation of this threatened group.

Cysteine-stabilized αß defensins: From a common fold to antibacterial activity.

Antimicrobial peptides (AMPs) seem to be promising alternatives to common antibiotics, which are facing increasing bacterial resistance. Among them are the cysteine-stabilized αß defensins. These peptides are small, with a length ranging from 34 to 54 amino acid residues, cysteine-rich and extremely stable, normally composed of an α-helix and three ß-strands stabilized by three or four disulfide bonds and commonly found in several organisms. Moreover, animal and plant CSαß defensins present different specificities, the first being mainly active against bacteria and the second against fungi. The role of the CSαß-motif remains unknown, but a common antibacterial mechanism of action, based on the inhibition of the cell-wall formation, has already been observed in some fungal and invertebrate defensins. In this context, the present work aims to group the data about CSαß defensins, highlighting their evolution, conservation, structural characteristics, antibacterial activity and biotechnological perspectives.

Insights into animal and plant lectins with antimicrobial activities.

Lectins are multivalent proteins with the ability to recognize and bind diverse carbohydrate structures. The glyco -binding and diverse molecular structures observed in these protein classes make them a large and heterogeneous group with a wide range of biological activities in microorganisms, animals and plants. Lectins from plants and animals are commonly used in direct defense against pathogens and in immune regulation. This review focuses on sources of animal and plant lectins, describing their functional classification and tridimensional structures, relating these properties with biotechnological purposes, including antimicrobial activities. In summary, this work focuses on structural-functional elucidation of diverse lectin groups, shedding some light on host-pathogen interactions; it also examines their emergence as biotechnological tools through gene manipulation and development of new drugs.

Effect of antiretroviral drugs on the DNA damage in mice.

In order to investigate the effects of two non-nucleoside reverse transcriptase inhibitors (NNRTIs) on the DNA damage in vivo, nevirapine (NVP; 3.3 mg/kg), efavirenz (EFV; 10 mg/kg) or saline were administered orally. Acute effects were analyzed 24 h after the administration of a single NNRTI dose, and subchronic effects 24 h after the last dose. Peripheral blood, brain, heart and liver samples were subjected to genotoxicity analyses and polychromatic erythrocytes from the bone marrow to micronucleus test. The micronucleus test did not reveal any significant differences between animals from the acute or subchronic groups. Comet assay showed that acute and subchronic NNRTI treatment did not cause any significant DNA damage in heart, liver or peripheral blood cells. However, increased damage indexes and frequencies were observed in the brain of mice, subchronically treated with EFV. This result suggests for the first time that this drug might induce genotoxicity in the brain.