Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales

<p>Abstract</p> <p>Background</p> <p>Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis.</p> <p>Results</p> <p>Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes.</p> <p>Conclusions</p> <p>The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle evolution in these microorganisms, although they may act in common stages of host infection. The phylogenetic analysis for many distinct operons involved in these processes emphasizes the relevance of horizontal gene transfer events in the symbiotic and pathogenic similarity.</p

Estoque de carbono nas frações granulométricas de latossolo amarelo em sistemas agroflorestais.

As alterações no estoque de carbono em Latossolo Amarelo distrófico resultantes da conversão de florestas secundárias em sistemas agroflorestais na Amazônia não são muito bem entendidas. O objetivo deste estudo foi avaliar o efeito da sucessão de floresta secundária em sistemas agroflorestais, no armazenamento de carbono nas frações particuladas (> 53µm) e associada a silte+argila (<53µm) de um Latossolo Amarelo distrófico da Amazônia Oriental. O estudo foi realizado no Nordeste do Pará, município de Tomé-Açu. Três sistemas agroflorestais com palma de óleo; Adubadeiras, Biodiverso mecanizado, Biodiverso manual foram comparados com um sistema de referência representado por uma floresta secundária. Utilizou-se técnica de preparo de área de corte-etrituração, amostras de solo foram coletadas em diferentes profundidades para determinação da concentração de carbono nas frações granulométricas associada a matéria orgânica e analisadas por combustão em analisador elementar. Os resultados mostraram que os maiores teores de carbono e densidade no solo foram alcançados pelos manejos que receberam a trituração da floresta e os maiores estoques de carbono total de 0-20 cm de profundidade foi observado no sistema de uso Adubadeiras. Os maiores estoques de carbono por fração foram verificados na fração particulada, mostrando que a fração lábil é mais sensível ao manejo do solo

Sylvopastoral system as a replacement of nitrogen fertilization of Brachiaria brizantha on Brazilian Northeast coastal tablelands.

In coastal tablelands (CT) of the Brazilian Northeast fertilization of pastures is a major factor for expression of their productive potential. Nitrogen is the highest responsive nutrient of such pastures. However, the use of fertilizer in the Northeast is still weak. An economical way to provide nitrogen to pasture and improving animal diet quality is the consortium of grass with tree forage legumes

Xylella fastidiosa comparative genomic database is an information resource to explore the annotation, genomic features, and biology of different strains

The Xylella fastidiosa comparative genomic database is a scientific resource with the aim to provide a user-friendly interface for accessing high-quality manually curated genomic annotation and comparative sequence analysis, as well as for identifying and mapping prophage-like elements, a marked feature of Xylella genomes. Here we describe a database and tools for exploring the biology of this important plant pathogen. The hallmarks of this database are the high quality genomic annotation, the functional and comparative genomic analysis and the identification and mapping of prophage-like elements. It is available from web site http://www.xylella.lncc.br

How likely are adaptive responses to mitigate the threats of climate change for amphibians globally?

Whether species are capable of adapting to rapid shifts in climate raises considerable interest. Analyses based on niche models often assume niche conservatism and equilibrium with climate, implying that species will persist only in regions where future climatic conditions match their current conditions and that they will colonize these regions promptly. However, species may adapt to changing climate and persist where future climates differ from their current optimum. Here, we provide a first macroecological generalization to the approach of evolutionary rescue, by comparing the expected shift in mean temperature within the geographic range of 7193 species of amphibians worldwide, under alternative warming scenarios. Expected evolutionary change is expressed in units of standard deviations of mean temperature, per generation (Haldanes) and compared with theoretical models defining the maximum sustainable evolutionary rates (MSER) for each species. For the pessimistic emission scenario RCP8.5, shifts in mean temperature vary between near-zero and 6°C within the geographic ranges for most species, with a median equal to 3.75°C. The probability of evolutionary rescue in temperature peaks is higher than 0.05 for about 55% of the species and higher than 0.95 for only 12% of the species. Therefore, the predicted shift in mean temperature would be too extreme to deal with for almost half of the species. When evolutionary plasticity is incorporated, this scenario becomes more optimistic, with about 44% of the species being likely to shift their thermal peaks tracking future warming. These figures are not random in geographical space: evolutionary rescue would be unlikely in the tropics, especially in South America (Amazonia), parts of Africa, Indonesia, and in the Mediterranean region. Given the uncertainty in demographic and genetic parameters for species’ responses to climate change, we caution that it remains difficult to assess the realism of the macroecological generalization. In any case, it may be precautionary to assume that our results are not liberal, showing low probability of adaptation for most of the species and thus that the persistence of populations by evolutionary rescue may, in general, be unlikely in the long term

Vaginal cytology as a tool to predict the time of ovulation in goats and sheep.

The detection of ovulation is of great importance for the use of reproductive biotechnologies in small ruminants. The ovulation is efficiently determined by ultrasound (US), equipment that is not always available and of relatively high cost. Therefore, the aim of this study was to identify the efficacy of vaginal cytology as a tool to determine the ovulation time in these species. The study was carried out during the non-breeding season, in Coronel Pacheco, Minas Gerais (21°35'S and 43°15'W). In sheep, the standard chosen was anucleated, but it had a high CV (23.7%), which led to non-high accuracy (66.7%). Therefore, PPV and NPV were 26% and 88%, respectively; the specificity was 45% and 64% at 24 h and 12 h before ovulation respectively; and finally, the sensitivity at the moment of ovulation was 55%. It can be concluded that the vaginal cytology may be an efficient tool to determine the moment of ovulation in goats, however it is less accurate in sheep

Can the time and conditions of incubation of in vivo-derived goat embryos compromise embryonic cryosurvival?.

Evidence suggests that the conditions after collection may compromise the survival of in vivo-derived (IVD) embryos after cryopreservation. To test this hypothesis, 150 IVD embryos (grade I and II) from 25 Alpine goats were divided into three groups after recovery on day 6 (D6; D0 = AI): P3 (n=50) – embryos maintained in a 35 mm cell culture dish with 2 mL of holding medium (HM; 301 mOsm/kg) at 37 °C for 3 h on a hotplate; P6 (n = 50) – embryos kept under the same conditions as the P3 group for 6-8 h; and T6 (n = 50) embryos maintained in cryovials containing 1 mL of HM at 37°C, for 6-8 h, in a transporter. Despite previous incubation on the transporter did not modify the survival rate after cryopreservation, when compared to incubation on the hot plate, the analysis performed revealed that the experimental condition of the T6 group is able to better maintain molecular aspects of IVD goat embryos after thawing, such as apoptotic incidence and ATP production.Edição dos resumos da 37ª Annual Meeting of the Brazilian Embryo Technology Society, 2024, Atibaia, SP