Are Ascaris lumbricoides and Ascaris suum a single species?

Since the original description and naming of Ascaris lumbricoides from humans by Linnaeus in 1758 and later of Ascaris suum from pigs by Goeze 1782, these species have been considered to be valid. Four hypotheses relative to the conspecificity or lack thereof (and thus origin of these species) are possible: 1) Ascaris lumbricoides (usually infecting humans) and Ascaris suum (recorded mostly from pigs) are both valid species, with the two species originating via a speciation event from a common ancestor sometime before the domestication of pigs by humans, or 2) Ascaris lumbricoides in humans is derived directly from the species A. suum found in pigs with A. suum then existing as a persistent ancestor after formation of A. lumbricoides, or 3) Ascaris suum is derived directly from A. lumbricoides with the persistent ancestor being A. lumbricoides and A. suum being the newly derived species, and finally, 4) Ascaris lumbricoides and A. suum are the same species, this hypothesis being supported by studies showing both low morphological and low genetic divergence at several genes. We present and discuss paleoparasitological and genetic evidence that complement new data to evaluate the origin and evolution of Ascaris spp. in humans and pigs, and the uniqueness of the species in both hosts. Finally, we conclude that Ascaris lumbricoides and A. suum are a single species and that the name A. lumbricoides Linnaeus 1758 has taxonomic priority; therefore A. suum Goeze 1782 should be considered a synonym of A. lumbricoides

Pegmatite fields of São Pedro de Ferros, Antônio Dias and Marilac, Minas Gerais State, Brazil: petrographic characterization

Pegmatites are rocks of granite or metastatic origin with gigantic crystals that are formed in fluid phase of the magmatic liquid enriched with incompatible elements, thats why they can be considered as gemstones and industrial minerals deposits. Both studied areas in the present article were genererated by anatexia process or partial fusion. The Jatobá Mine in the Pegmatitic Field of Ferros-Antônio Dias, in Santa Maria de Itabira, explores the aquamarine gem, a beryl variety, in a pegmatite that is located closer to the granite system of the quartz core and is docked in a gnaisse granitic rock from the Guanhães Complex. The collected sample was denominated like Quartzo alkali feldspar sienite in the Diagram QAPF. The blue color of the beryl is given by the intrusion of Fe. The Duas Cores Mining represents the Pegmatitic Field of Marilac, near Governador Valadares, and the exploration of bi-color tourmaline will begin soon. This mineral is in a very weathered pegmatite, positioned more at the end of the granite system and docked in the mica-schist rock of the São Tomé Formation. The sample was named Tonalite by the QAPF Diagram. The color variation of the explored gem is related to the enrichment of the Li element at the site

Grasses control strategies in setting restoration stand of the Atlantic Forest.

This study aimed to assess the effectiveness of four weed control strategies in forest setting stands linked by a set of Atlantic Forest tree species. Four treatments were employed: mechanical ? manual hoeing and mowing; chemical ? glyphosate herbicide application in the total area; chemical ? cultural ? herbicide spraying and herbaceous legume intercropping; chemical-mechanical ? herbicide planting in rows and mowing in the interrows. Diameter, crown area and soil cover percentage of the eight tree species were assessed at 18 months. Herbicide spraying in total area promoted the greatest reduction in weed populations, as well as superior growth in height, diameter, crown area and soil cover of the tree species. More interventions were necessary in the treatment of mechanical weed control that has also shown the least growth of the tree species. The chemical method was the most effective in weed control and promoted the greatest growth of the tree speci

Differences in physiology explain succession of mixoplankton functional types and affect carbon fluxes in temperate seas

Different hypotheses have been proposed explaining plankton community assembly and how changes in biodiversity can impact ecosystem function. Mixoplankton (photo-phago-trophs) are important members of the plankton, butscience lacks a clear understanding of their role in plankton succession. Here, we used a modelling approach to evaluate the seasonalities of mixoplankton functional types (MFTs) and to test the hypothesis that functional differences affect their roles in key carbon fluxes. Functional differences were modelled based on cell size and whether mixoplankton possess their own, or acquire, photosystems. Ecosystem simulations incorporated realistic environmental variability and were validated against a 9 yr long-term time series of nutrients, chlorophyll-a, and plankton data from a coastal temperate sea. Simulations, consistent with empirical data, show that mixoplankton of different sizes are present throughout the water column and over time, with seasonal population dynamics differing among the different MFTs. Importantly, the partitioning of production among different size-classes depends on how mixoplankton functional diversity is described in the model, and that merging mixoplankton into one functional type can mask their diverse ecological roles in carbon cycling. Mixoplankton thus play an important role in structuring the plankton community and its dynamics in the simulations

The intestinal expulsion of the roundworm Ascaris suum is associated with eosinophils, intra-epithelial T cells and decreased intestinal transit time

Ascaris lumbricoides remains the most common endoparasite in humans, yet there is still very little information available about the immunological principles of protection, especially those directed against larval stages. Due to the natural host-parasite relationship, pigs infected with A. suum make an excellent model to study the mechanisms of protection against this nematode. In pigs, a self-cure reaction eliminates most larvae from the small intestine between 14 and 21 days post infection. In this study, we investigated the mucosal immune response leading to the expulsion of A. suum and the contribution of the hepato-tracheal migration. Self-cure was independent of previous passage through the liver or lungs, as infection with lung stage larvae did not impair self-cure. When animals were infected with 14-day-old intestinal larvae, the larvae were being driven distally in the small intestine around 7 days post infection but by 18 days post infection they re-inhabited the proximal part of the small intestine, indicating that more developed larvae can counter the expulsion mechanism. Self-cure was consistently associated with eosinophilia and intra-epithelial T cells in the jejunum. Furthermore, we identified increased gut movement as a possible mechanism of self-cure as the small intestinal transit time was markedly decreased at the time of expulsion of the worms. Taken together, these results shed new light on the mechanisms of self-cure that occur during A. suum infections

EQUATIONS TO ESTIMATE THE CARBON STOCK PER HECTARE IN STEMS OF TREES IN SEASONAL SEMIDECIDUAL FOREST

The aim of this study was to adjust equations to estimate the carbon stock per hectare in stems of trees in function of forest variables, obtained by horizontal point sampling (Bitterlich method). Were sampled 55 points with a basal area factor K = 1, in natural forest fragments, located at Vi\ue7osa, Minas Gerais. After adjustment and evaluation of different regression models, was verified that the model 8 (non-linear) were the most precise to estimate the carbon stock per hectare in the stems of trees.Este trabalho teve por objetivo ajustar equa\ue7\uf5es para estimar o estoque de carbono por hectare nos fustes das \ue1rvores, em fun\ue7\ue3o de vari\ue1veis da floresta obtidas por meio da amostragem por ponto horizontal (m\ue9todo de Bitterlich). Foram amostrados 55 pontos, com um fator de \ue1rea basal igual a 1, em fragmentos de floresta estacional semidecidual, no munic\uedpio de Vi\ue7osa, Minas Gerais. Ap\uf3s o ajuste e a avalia\ue7\ue3o de diferentes modelos de regress\ue3o lineares e n\ue3o lineares, verificou-se que as equa\ue7\uf5es referentes ao modelo 8 (n\ue3o linear) foram as mais precisas para estimar o estoque de carbono por hectare nos fustes das \ue1rvores

Diversidade genética da comunidade bacteriana durante a compostagem de resíduos agrícolas enriquecidos com rochas e bioinoculante.

FertBio 2016

The Mitochondrial Genome of Baylisascaris procyonis

BACKGROUND: Baylisascaris procyonis (Nematoda: Ascaridida), an intestinal nematode of raccoons, is emerging as an important helminthic zoonosis due to serious or fatal larval migrans in animals and humans. Despite its significant veterinary and public health impact, the epidemiology, molecular ecology and population genetics of this parasite remain largely unexplored. Mitochondrial (mt) genomes can provide a foundation for investigations in these areas and assist in the diagnosis and control of B. procyonis. In this study, the first complete mt genome sequence of B. procyonis was determined using a polymerase chain reaction (PCR)-based primer-walking strategy. METHODOLOGY/PRINCIPAL FINDINGS: The circular mt genome (14781 bp) of B. procyonis contained 12 protein-coding, 22 transfer RNA and 2 ribosomal RNA genes congruent with other chromadorean nematodes. Interestingly, the B. procyonis mtDNA featured an extremely long AT-rich region (1375 bp) and a high number of intergenic spacers (17), making it unique compared with other secernentean nematodes characterized to date. Additionally, the entire genome displayed notable levels of AT skew and GC skew. Based on pairwise comparisons and sliding window analysis of mt genes among the available 11 Ascaridida mtDNAs, new primer pairs were designed to amplify specific short fragments of the genes cytb (548 bp fragment) and rrnL (200 bp fragment) in the B. procyonis mtDNA, and tested as possible alternatives to existing mt molecular beacons for Ascaridida. Finally, phylogenetic analysis of mtDNAs provided novel estimates of the interrelationships of Baylisasaris and Ascaridida. CONCLUSIONS/SIGNIFICANCE: The complete mt genome sequence of B. procyonis sequenced here should contribute to molecular diagnostic methods, epidemiological investigations and ecological studies of B. procyonis and other related ascaridoids. The information will be important in refining the phylogenetic relationships within the order Ascaridida and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of parasitic nematodes of socio-economic importance