Atividade alelopática de Nerium Oleander L. e Dieffenbachia picta schott em sementes de Lactuca Sativa L. e Bidens pilosa L.

Aqueous extracts from green leaves of Nerium oleander L. and Dieffenbachia picta in concentrations of 0; 0,0625; 0,125 and 0,25 mg/mL were prepared with the objective of studying the allelopathic potential of these ornamental plant species on lettuce (test plant) and Bidens pilosa L seeds. The experiments were carried out in January of 2007, at the Genetic Laboratory of Santa Maria Federal University. The first count of germination (PCG), germination (G), germination speed index (IVG), root and shoot length, and fresh biomass (MF) were evaluated. Both species showed tendency to reduce the analyzed morphological variables from the concentration of 0,125 mg/mL. The seeds of Bidens pilosa L. were more sensible to aqueous extracts than lettuce seeds. The IVG showed the greatest reduction with the increase of extracts concentration. The MF of lettuce and Bidens pilosa L. plants were reduced from the concentration of 0,0625 mg/mL. Both extracts showed potential allelopathic activity.Extratos aquosos de folhas verdes de Nerium oleander L. Dieffenbachia picta nas concentrações 0; 0,0625; 0,125 e 0,25 mg/mL foram preparados com o objetivo de determinar o potencial alelopático dessas espécies utilizadas como plantas ornamentais, sobre sementes de Lactuca sativa (planta-teste) e Bidens pilosa L. O experimento foi conduzido durante o mês de janeiro de 2007, no Laboratório de Genética da Universidade Federal de Santa Maria. Foram avaliados a primeira contagem da germinação (PCG), germinação (G), o índice de velocidade de germinação (IVG), os comprimentos das raízes e da parte aérea e a biomassa fresca (MF). Ambas as espécies mostraram tendência a reduzirem os parâmetros morfológicos analisados a partir da concentração de 0,125 mg/mL, sendo que as sementes de Bidens pilosa L. foram mais sensíveis que às de alface. O IVG foi a variável que mostrou maior redução com o aumento da concentração dos extratos. A MF das plântulas de alface e Bidens pilosa L. foram reduzidas a partir da concentração de 0,0625 mg/mL. Ambos extratos mostraram atividade potencialmente alelopática

Beyond diversity loss and climate change : impacts of Amazon deforestation on infectious diseases and public health

Amazonian biodiversity is increasingly threatened due to the weakening of policies for combating deforestation, especially in Brazil. Loss of animal and plant species, many not yet known to science, is just one among many negative consequences of Amazon deforestation. Deforestation affects indigenous communities, riverside as well as urban populations, and even planetary health. Amazonia has a prominent role in regulating the Earth’s climate, with forest loss contributing to rising regional and global temperatures and intensification of extreme weather events. These climatic conditions are important drivers of emerging infectious diseases, and activities associated with deforestation contribute to the spread of disease vectors. This review presents the main impacts of Amazon deforestation on infectious-disease dynamics and public health from a One Health perspective. Because Brazil holds the largest area of Amazon rainforest, emphasis is given to the Brazilian scenario. Finally, potential solutions to mitigate deforestation and emerging infectious diseases are presented from the perspectives of researchers in different fields

Fumigant Activity of the Psidium guajava

The guava fruit, Psidium guajava var. pomifera (Myrtaceae family), is a native plant from South America. Its leaves and fruits are widely used in popular medicine in tropical and subtropical countries. Drosophila melanogaster has been used as one of the main model organisms in genetic studies since the 1900s. The extensive knowledge about this species makes it one of the most suitable organisms to study many aspects of toxic compound effects. Due to the lack of studies on the effects of the bioactive compounds present in the P. guajava var. pomifera essential oil, we performed a phytochemical characterization by CG-MS and evaluated the toxicity induced by the essential oil in the D. melanogaster insect model. In order to understand the biochemical mechanisms of toxicity, changes on the Nrf2 signaling as well as hallmarks of oxidative stress response were followed in the exposed flies. Our results showed that exposure of insects to the P. guajava oil increased mortality and locomotor deficits in parallel with an oxidative stress response signaling. Therefore, it suggested a bioinsecticidal activity for P. guajava volatile compounds by means of oxidative stress. Further studies are ongoing to identify which oil compounds are responsible for such effect

Lying in Wait: The Resurgence of Dengue Virus After the Zika Epidemic in Brazil

After the Zika virus (ZIKV) epidemic in the Americas in 2016, both Zika and dengue incidence declined to record lows in many countries in 2017-2018, but in 2019 dengue resurged in Brazil, causing ~2.1 million cases. In this study we use epidemiological, climatological and genomic data to investigate dengue dynamics in recent years in Brazil. First, we estimate dengue virus force of infection (FOI) and model mosquito-borne transmission suitability since the early 2000s. Our estimates reveal that DENV transmission was low in 2017-2018, despite conditions being suitable for viral spread. Our study also shows a marked decline in dengue susceptibility between 2002 and 2019, which could explain the synchronous decline of dengue in the country, partially as a result of protective immunity from prior ZIKV and/or DENV infections. Furthermore, we performed phylogeographic analyses using 69 newly sequenced genomes of dengue virus serotype 1 and 2 from Brazil, and found that the outbreaks in 2018-2019 were caused by local DENV lineages that persisted for 5-10 years, circulating cryptically before and after the Zika epidemic. We hypothesize that DENV lineages may circulate at low transmission levels for many years, until local conditions are suitable for higher transmission, when they cause major outbreaks

Incipient parallel evolution of SARS-CoV-2 Deltacron variant in South Brazil

With the coexistence of multiple lineages and increased international travel, recombination and gene flow are likely to become increasingly important in the adaptive evolution of SARS-CoV-2. These processes could result in genetic introgression and the incipient parallel evolution of multiple recombinant lineages. However, identifying recombinant lineages is challenging, and the true extent of recombinant evolution in SARS-CoV-2 may be underestimated. This study describes the first SARS-CoV-2 Deltacron recombinant case identified in Brazil. We demonstrate that the recombination breakpoint is at the beginning of the Spike gene. The 5′ genome portion (circa 22 kb) resembles the AY.101 (Delta), and the 3′ genome portion (circa 8 kb nucleotides) is most similar to the BA.1.1 (Omicron). Furthermore, evolutionary genomic analyses indicate that the new strain emerged after a single recombination event between lineages of diverse geographical locations in December 2021 in South Brazil. This Deltacron, AYBA-RS, is one of the dozens of recombinants described in 2022. The submission of only four sequences in the GISAID database suggests that this lineage had a minor epidemiological impact. However, the recent emergence of this and other Deltacron recombinant lineages (XD, XF, and XS) suggests that gene flow and recombination may play an increasingly important role in the COVID-19 pandemic. We explain the evolutionary and population genetic theory that supports this assertion, concluding that this stresses the need for continued genomic surveillance. This monitoring is vital for countries where multiple variants are present, as well as for countries that receive significant inbound international travel

Genetic exchange in eukaryotes through horizontal transfer: connected by the mobilome

International audienceBACKGROUND:All living species contain genetic information that was once shared by their common ancestor. DNA is being inherited through generations by vertical transmission (VT) from parents to offspring and from ancestor to descendant species. This process was considered the sole pathway by which biological entities exchange inheritable information. However, Horizontal Transfer (HT), the exchange of genetic information by other means than parents to offspring, was discovered in prokaryotes along with strong evidence showing that it is a very important process by which prokaryotes acquire new genes.MAIN BODY:For some time now, it has been a scientific consensus that HT events were rare and non-relevant for evolution of eukaryotic species, but there is growing evidence supporting that HT is an important and frequent phenomenon in eukaryotes as well.CONCLUSION:Here, we will discuss the latest findings regarding HT among eukaryotes, mainly HT of transposons (HTT), establishing HTT once and for all as an important phenomenon that should be taken into consideration to fully understand eukaryotes genome evolution. In addition, we will discuss the latest development methods to detect such events in a broader scale and highlight the new approaches which should be pursued by researchers to fill the knowledge gaps regarding HTT among eukaryotes

VHICA, a New Method to Discriminate between Vertical and Horizontal Transposon Transfer: Application to the Mariner Family within Drosophila

Submitted by Adagilson Silva ([email protected]) on 2017-09-04T13:27:40Z No. of bitstreams: 1 26685176 2016 wal-vhi.oa.pdf: 1677888 bytes, checksum: ee8f4b273e2f6eb33d63b513a37497fd (MD5)Approved for entry into archive by Adagilson Silva ([email protected]) on 2017-09-04T14:09:51Z (GMT) No. of bitstreams: 1 26685176 2016 wal-vhi.oa.pdf: 1677888 bytes, checksum: ee8f4b273e2f6eb33d63b513a37497fd (MD5)Made available in DSpace on 2017-09-04T14:09:51Z (GMT). No. of bitstreams: 1 26685176 2016 wal-vhi.oa.pdf: 1677888 bytes, checksum: ee8f4b273e2f6eb33d63b513a37497fd (MD5) Previous issue date: 2016-04Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil / Universidade Federal de Santa Maria. Pós Graduação em Biodiversidade Animal. Santa Maria, RS, Brasil.CNRS, IRD, Universit e Paris-Sud. Laboratoire Evolution, Genomes, Comportement, Ecologie. Gif-sur-Yvette, France / Universit e Paris-Saclay. Orsay, France.Universidade Federal de Santa Maria. Pós Graduação em Biodiversidade Animal. Santa Maria, RS, Brasil / Universidade Federal de Santa Maria. Departamento de Bioquımica e Biologia Molecular. Santa Maria, RS, Brasil.CNRS, IRD, Universit e Paris-Sud. Laboratoire Evolution, Genomes, Comportement, Ecologie. Gif-sur-Yvette, France / Universit e Paris-Saclay. Orsay, France.CNRS, IRD, Universit e Paris-Sud. Laboratoire Evolution, Genomes, Comportement, Ecologie. Gif-sur-Yvette, France / Universit e Paris-Saclay. Orsay, France.Transposable elements (TEs) are genomic repeated sequences that display complex evolutionary patterns. They are usually inherited vertically, but can occasionally be transmitted between sexually independent species, through so-called horizontal transposon transfers (HTTs). Recurrent HTTs are supposed to be essential in life cycle of TEs, which are otherwise destined for eventual decay. HTTs also impact the host genome evolution. However, the extent of HTTs in eukaryotes is largely unknown, due to the lack of efficient, statistically supported methods that can be applied to multiple species sequence data sets. Here, we developed a new automated method available as a R package "vhica" that discriminates whether a given TE family was vertically or horizontally transferred, and potentially infers donor and receptor species. The method is well suited for TE sequences extracted from complete genomes, and applicable to multiple TEs and species at the same time. We first validated our method using Drosophila TE families with well-known evolutionary histories, displaying both HTTs and vertical transmission. We then tested 26 different lineages of mariner elements recently characterized in 20 Drosophila genomes, and found HTTs in 24 of them. Furthermore, several independent HTT events could often be detected within the same mariner lineage. The VHICA (Vertical and Horizontal Inheritance Consistence Analysis) method thus appears as a valuable tool to analyze the evolutionary history of TEs across a large range of species

In silico predictions of protein interactions between Zika virus and human host

Background The ZIKA virus (ZIKV) belongs to the Flaviviridae family, was first isolated in the 1940s, and remained underreported until its global threat in 2016, where drastic consequences were reported as Guillan-Barre syndrome and microcephaly in newborns. Understanding molecular interactions of ZIKV proteins during the host infection is important to develop treatments and prophylactic measures; however, large-scale experimental approaches normally used to detect protein-protein interaction (PPI) are onerous and labor-intensive. On the other hand, computational methods may overcome these challenges and guide traditional approaches on one or few protein molecules. The prediction of PPIs can be used to study host-parasite interactions at the protein level and reveal key pathways that allow viral infection. Results Applying Random Forest and Support Vector Machine (SVM) algorithms, we performed predictions of PPI between two ZIKV strains and human proteomes. The consensus number of predictions of both algorithms was 17,223 pairs of proteins. Functional enrichment analyses were executed with the predicted networks to access the biological meanings of the protein interactions. Some pathways related to viral infection and neurological development were found for both ZIKV strains in the enrichment analysis, but the JAK-STAT pathway was observed only for strain PE243 when compared with the FSS13025 strain. Conclusions The consensus network of PPI predictions made by Random Forest and SVM algorithms allowed an enrichment analysis that corroborates many aspects of ZIKV infection. The enrichment results are mainly related to viral infection, neuronal development, and immune response, and presented differences among the two compared ZIKV strains. Strain PE243 presented more predicted interactions between proteins from the JAK-STAT signaling pathway, which could lead to a more inflammatory immune response when compared with the FSS13025 strain. These results show that the methodology employed in this study can potentially reveal new interactions between the ZIKV and human cells

Revisiting Key Entry Routes of Human Epidemic Arboviruses into the Mainland Americas through Large-Scale Phylogenomics

The rapid worldwide spread of chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses have raised great international concern. Knowledge about the entry routes and geographic expansion of these arboviruses to the mainland Americas remain incomplete and controversial. Epidemics caused by arboviruses continue to cause socioeconomic burden globally, particularly in countries where vector control is difficult due to climatic or infrastructure factors. Understanding how the virus circulates and moves from one country to another is of paramount importance to assist government and health officials in anticipating future epidemics, as well as to take steps to help control or mitigate the spread of the virus. Through the analyses of the sequences of arbovirus genomes collected at different locations over time, we identified patterns of accumulated mutations, being able to trace routes of dispersion of these viruses. Here, we applied robust phylogenomic methods to trace the evolutionary dynamics of these arboviruses with special focus on Brazil, the epicenter of these triple epidemics. Our results show that CHIKV, DENV-1–4, and ZIKV followed a similar path prior to their first introductions into the mainland Americas, underscoring the need for systematic arboviral surveillance at major entry points of human population movement between countries such as airports and seaports