Bacteroides fragilis Toxin Coordinates a Pro-carcinogenic Inflammatory Cascade via Targeting of Colonic Epithelial Cells

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Species assignment and population genetic studies of Gran Paraná pejerrey (<Emphasis Type="Italic">Odontesthes</Emphasis> sp., Atheriniformes,Atherinopsidae) from La Plata Basin in South America

Since 2013, the pelagic zone of Upper Lake Constance (ULC) has been subject to a massive invasion of the non-native three-spined stickleback (Gasterosteus aculeatus Linnaeus, 1758). Data from monthly monitoring of pelagic whitefish (Coregonus wartmanni Bloch, 1784) were used to compare weight-at-age and abundance of pelagic whitefish for years before (1997–2012) and after the invasion (2013–2015). Growth and abundance of pelagic whitefish is shown to be heavily influenced by stickleback presence. Mean autumn weight-at-age of whitefish decreased by 33.3% after the invasion took place and a significant decline in autumn CPUE in otherwise unfished cohorts of the population was also recorded. The results imply direct effects of stickleback presence on pelagic whitefish, including interspecific competition for food leading to reduced growth and survival, and predation of eggs and larvae, hampering recruitment. These observations coincide with a sharp decline in whitefish yield. In conclusion, this study shows that the invasion of stickleback has substantially altered the pelagic fish community of ULC, with severe consequences for commercial fisheries.     

Richness,species composition and functional groups in Agaricomycetes communities along a vegetation and elevational gradient in the Andean Yungas of Argentina

The Neotropics are among the least explored regions from a mycological perspective. A few recent molecular studies in South America have shown high fungal diversity as well as numerous groups of mostly undescribed taxa. Through soil metabarcoding analysis we compared richness and species composition among macrofungal communities, belonging to Agaricales, Russulales, Boletales and Phallomycetidae groups, in three elevational forests types in the subtropical Yungas of Northwestern Argentina (Piedmont forest; Montane forest, Montane cloud forest). The aims of this study were to assess richness of taxonomic and functional groups along the elevation gradient and to assess the relationships between environmental variables and species composition in the studied fungal communities. The results have shown rich Agaricomycetes communities, diversely structured among forests habitats. The elevation gradient differentially affected the richness and distribution of Agaricales, Russulales, Boletales and Phallomycetidae. Based on fungal trophic modes and guilds, the gradient also affected the ectomycorrhizal taxa distribution. When considering the basidiomata growth forms (agaricoid, boletoid, gasteroid, etc.), only the secotioid type showed significant elevational differences. Additional analyses indicated that saprotrophic nutritional mode was dominant along the entire gradient, being partially replaced by biotrophic modes at higher elevations. Fungal communities in the Montane cloud forests are most dissimilar when compared with communities at the Piedmont forest and Montane forest, which is consistent with the different biogeographic origins of these forests. DNA metabarcoding sequence analysis provided detailed information on the diversity and taxonomic and functional composition of macrofungal communities.     

Female preference for males that have exclusively marked or invaded territories depends on male presence and its identity in the subterranean rodent Ctenomys talarum

Territorial scent‐marking provides chemical records of male competitive interactions that are available to females, who gain valuable information to assess and identify best quality partners. In this context, the solitary subterranean rodent tuco‐tuco (Ctenomys talarum) offers excellent possibilities to evaluate the effects of male exclusive scent‐marking of territories on female assessment. For evaluation, we used wild caught individuals of C. talarum, manipulated their scent marks within the territories in captive conditions and staged preference tests where females were able to choose between exclusive and invaded territories. The evaluation was performed in two scenarios considering the identity of the intruder scent mark: territories invaded by a strange male and territories invaded by a neighbour male. Females investigated the chemical cues deposited on the substrate of the exclusively marked territory more frequently. Next, females displayed equal interest to scent samples of both males presented in a Y‐maze. Finally, when females could gain access to both individually isolated males and their scent‐marked territories, they spent more time within invaded territories despite they visited them with the same frequency. Moreover, females tried to get in contact by scratching the mesh of the owner of the invaded territory more frequently. We found that females of C. talarum evaluate the homogeneity (exclusiveness) of scent marks within a male territory and then show preferences in relation to the identity of the intruder's scent –whether strange or neighbour.     

<Emphasis Type="Italic">Paenibacillus</Emphasis> sp. A59 GH10 and GH11 Extracellular Endoxylanases: Application in Biomass Bioconversion

The cost-efficient degradation of xylan to fermentable sugars is of particular interest in second generation bioethanol production, feed, food, and pulp and paper industries. Multiple potentially secreted enzymes involved in polysaccharide deconstruction are encoded in the genome of Paenibacillus sp. A59, a xylanolytic soil bacterium, such as three endoxylanases, seven GH43 β-xylosidases, and two GH30 glucuronoxylanases. In secretome analysis of xylan cultures, ten glycoside hydrolases were identified, including the three predicted endoxylanases, confirming their active role. The two uni-modular xylanases, a 32-KDa GH10 and a 20-KDa GH11, were recombinantly expressed and their activity on xylan was confirmed (106 and 85 IU/mg, respectively), with differences in their activity pattern. Both endoxylanases released mainly xylobiose (X2) and xylotriose (X3) from xylan and pre-treated biomasses (wheat straw, barley straw, and sweet corn cob), although only rGH10XynA released xylose (X1). rGH10XynA presented optimal conditions at pH 6, with thermal stability at 45–50 °C, while rGH11XynB showed activity in a wider range of pH, from 5 to 9, and was thermostable only at 45 °C. Moreover, GH11XynB presented sigmoidal kinetics on xylan, indicating possible cooperative binding, which was further supported by the structural model. This study provides a detailed analysis of the complete set of carbohydrate-active enzymes encoded in Paenibacillus sp. A59 genome and those effectively implicated in hemicellulose hydrolysis, contributing to understanding the mechanisms necessary for the bioconversion of this polysaccharide. Moreover, the two main free secreted xylanases, rGH10XynA and rGH11XynB, were fully characterized, supporting their potential application in industrial bioprocesses on lignocellulosic biomass.     

Early Woody Invasion Under Tree Plantations in Costa Rica: Implications for Forest Restoration

The role of tree plantations as facilitators of tropical forest restoration in degraded lands has been explored recently, but there are few data on the effect of different tree species on invasion of the plant understory. We evaluated early patterns of understory composition in three-year-old native tree plantations in lowland Costa Rica using two pure-species treatment (Jacaranda copaia and Vochysia guatemalensis) and one mixed-species treatment (J. copaia, V. guatemalensis, Stryphnodendron microstachyum, and Calophyllum brasiliense). We also monitored woody invasion in unplanted control areas dominated by grasses. The understory of the different plantation treatments differed in light environment, woody-plant growth and recruitment, and quantity and quality of woody regeneration. Forest tree invasion appeared to be enhanced under Vochysia, while shrubs were more abundant under the Jacaranda and mixed-species treatments. Woody plant growth, herbaceous cover, and understory light availability were highest under Jacaranda, intermediate under mixed species, and lowest under Vochysia. Soil-stored seeds seemed an important source for woody plant recruitment in Jacaranda and mixed species and of minimal importance under Vochysia, probably due to light suppression. It appears that competition from grasses is a major factor influencing early woody invasion in our study area. We found no woody recruitment after one year in the unplanted controls. We suggest that to promote the use of plantations as tools of forest restoration, there is a need to gather basic ecological information on how different tree species may influence patterns of plant understory colonization.     

Treatment of thermophilic hydrolysis reactor effluent with ceramic microfiltration membranes

Bioprocess and Biosystems Engineering - For an undisturbed operation of two-stage high-pressure fermentation up to 100&nbsp;bar, a particle-free hydrolysate appears to be necessary. This is...