Aquatic macroinvertebrate responses to native and non-native predators

Non-native species can profoundly affect native ecosystems through trophic interactions with native species. Native prey may respond differently to non-native versus native predators since they lack prior experience. Here we investigate antipredator responses of two common freshwater macroinvertebrates, Gammarus pulex and Potamopyrgus jenkinsi, to olfactory cues from three predators; sympatric native fish (Gasterosteus aculeatus), sympatric native crayfish (Austropotamobius pallipes), and novel invasive crayfish (Pacifastacus leniusculus). G. pulex responded differently to fish and crayfish; showing enhanced locomotion in response to fish, but a preference for the dark over the light in response to the crayfish. P. jenkinsi showed increased vertical migration in response to all three predator cues relative to controls. These different responses to fish and crayfish are hypothesised to reflect the predators’ differing predation types; benthic for crayfish and pelagic for fish. However, we found no difference in response to native versus invasive crayfish, indicating that prey naiveté is unlikely to drive the impacts of invasive crayfish. The Predator Recognition Continuum Hypothesis proposes that benefits of generalisable predator recognition outweigh costs when predators are diverse. Generalised responses of prey as observed here will be adaptive in the presence of an invader, and may reduce novel predators’ potential impacts

Comprehensive Thermodynamic Study of the Calcium Sulfate–Water Vapor System. Part 2: Physical Modeling of Adsorption Phenomena

International audienceWe employ a rigorous thermodynamic modeling approach to investigate the water adsorption phenomena on two calcium sulfate compounds, AIII-CaSO4 and CaSO4·0.5H2O. In part 1 of this work ( Ind. Eng. Chem. Res., 2019, DOI: 10.1021/acs.iecr.9b00856), we prepared these two products by the dehydration of synthetic CaSO4·2H2O and obtained quantitative adsorption data as a function of the temperature and water vapor partial pressure. In this part, we develop macroscopic solution models (ideal and nonideal) to model monolayer adsorption on AIII-CaSO4. This allowed the calculation of the energies of adsorption for this phenomenon, evidencing a physisorption mechanism. For the CaSO4·0.5H2O, we interpreted the water adsorption using a multilayer adsorption model (BET model). For both materials, we showed that nitrogen adsorption data was not sufficient to represent their entire surface areas and porosity profiles compared to their water vapor sorption capacity

Comprehensive Thermodynamic Study of the Calcium Sulfate–Water Vapor System. Part 1: Experimental Measurements and Phase Equilibria

International audienceThe calcium sulfate–water vapor system is of great scientific and technological importance due to its applications in several fields such as the construction materials industry, geology, and planetary sciences. While much effort has been concentrated during the past decades on characterizing the crystallographic structure of the different calcium sulfate polymorphs, some questions concerning their thermodynamic aspects as phase equilibria and their capability to increase their overall water content continuously beyond structural water content seem to have been left aside. Nevertheless, the comprehension of these aspects is of the utmost importance if we want to understand this chemical system fully. The present two-part work investigates these phenomena experimentally and by a thermodynamic modeling approach. In this first part, we develop a rigorous experimental protocol by thermogravimetric analysis under controlled temperature and water vapor partial pressure. We use this protocol to obtain thermodynamic equilibrium values for the overall water content of calcium sulfate hydrates. To ensure that the equilibrium was reached, we verified that these values could be obtained by distinct thermodynamic paths. With the equilibrium data, we were able to propose an updated equilibrium curve between soluble anhydrite AIII-CaSO4 and CaSO4·0.5H2O and estimate the thermodynamic parameters ΔrH° = (35.5 ± 1.0) kJ·mol–1 and ΔrS° = (80.0 ± 2.8) J·mol–1·K–1. After that, we were able to quantify the extent of water adsorption as a function of (T, PH2O), and we observed that it could represent a significant part of the overall water content of calcium sulfates

Aislamiento de Sporothrix pallida y Trichophyton rubrum en onicomicosis de mano

Se presenta un caso de onicomicosis de mano, de la cual se aisló en repetidas ocasiones Sporothrix pallida y Trichophyton rubrum. Se discute sobre los principales agentes de onicomicosis, el rol de los hongos ambientales y del aislamiento de S.pallida en este y en otro tipo de muestras

A genomic perspective on the potential of Actinobacillus succinogenes for industrial succinate production

<p>Abstract</p> <p>Background</p> <p>Succinate is produced petrochemically from maleic anhydride to satisfy a small specialty chemical market. If succinate could be produced fermentatively at a price competitive with that of maleic anhydride, though, it could replace maleic anhydride as the precursor of many bulk chemicals, transforming a multi-billion dollar petrochemical market into one based on renewable resources. <it>Actinobacillus succinogenes </it>naturally converts sugars and CO₂into high concentrations of succinic acid as part of a mixed-acid fermentation. Efforts are ongoing to maximize carbon flux to succinate to achieve an industrial process.</p> <p>Results</p> <p>Described here is the 2.3 Mb <it>A. succinogenes </it>genome sequence with emphasis on <it>A. succinogenes</it>'s potential for genetic engineering, its metabolic attributes and capabilities, and its lack of pathogenicity. The genome sequence contains 1,690 DNA uptake signal sequence repeats and a nearly complete set of natural competence proteins, suggesting that <it>A. succinogenes </it>is capable of natural transformation. <it>A. succinogenes </it>lacks a complete tricarboxylic acid cycle as well as a glyoxylate pathway, and it appears to be able to transport and degrade about twenty different carbohydrates. The genomes of <it>A. succinogenes </it>and its closest known relative, <it>Mannheimia succiniciproducens</it>, were compared for the presence of known Pasteurellaceae virulence factors. Both species appear to lack the virulence traits of toxin production, sialic acid and choline incorporation into lipopolysaccharide, and utilization of hemoglobin and transferrin as iron sources. Perspectives are also given on the conservation of <it>A. succinogenes </it>genomic features in other sequenced Pasteurellaceae.</p> <p>Conclusions</p> <p>Both <it>A. succinogenes </it>and <it>M. succiniciproducens </it>genome sequences lack many of the virulence genes used by their pathogenic Pasteurellaceae relatives. The lack of pathogenicity of these two succinogens is an exciting prospect, because comparisons with pathogenic Pasteurellaceae could lead to a better understanding of Pasteurellaceae virulence. The fact that the <it>A. succinogenes </it>genome encodes uptake and degradation pathways for a variety of carbohydrates reflects the variety of carbohydrate substrates available in the rumen, <it>A. succinogenes</it>'s natural habitat. It also suggests that many different carbon sources can be used as feedstock for succinate production by <it>A. succinogenes</it>.</p

EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2013. Scientific Opinion on the substantiation of a health claim related to “non - fermentable ” carbohydrates and maintenance of tooth mineralisation by decreasing tooth demineralisation pursuant to Article 13(5) of Regulation (EC) No 1924/2006

Following an application from Roquette Frères, submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of France, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to Nutriose® which should replace “fermentable carbohydrates” in foods or beverages in order to obtain the claimed effect, i.e. maintenance of tooth mineralisation by reducing tooth demineralisation. From the information provided, the Panel noted that the main characteristic of carbohydrates which is relevant to the claimed effect is the rate and amount of acid production resulting from their fermentation by saccharolytic bacteria in the oral cavity. This Opinion applies to “non-fermentable” carbohydrates, which should replace “fermentable” carbohydrates in foods or beverages in order to obtain the claimed effect. The Panel considers that maintaining tooth mineralisation by reducing tooth demineralisation resulting from acid production in plaque caused by the fermentation of carbohydrates is a beneficial physiological effect. The Panel concludes that a cause and effect relationship has been established between the consumption of foods/beverages containing “fermentable” carbohydrates at an exposure frequency of four or more times daily and an increased tooth demineralisation, and that the consumption of foods/beverages containing “non-fermentable” carbohydrates instead of “fermentable” carbohydrates may maintain tooth mineralisation by decreasing tooth demineralisation. In order to bear the claim, “fermentable” carbohydrates should be replaced in foods or beverages by “non-fermentable” carbohydrates, so that consumption of such foods or beverages does not lower plaque pH below 5.7 during and up to 30 minutes after consumption, and does not lead to dental erosion

EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to E<em>ff</em>_EXT™ and maintenance of normal joint mobility pursuant to Article 13(5) of Regulation (EC) No 1924/2006

Following an application from Nutrilinks Sarl, submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Belgium, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to EffEXT™ and maintenance of normal joint mobility. The Panel considers that EffEXT™, which is standardised pure krill oil, is sufficiently characterised. The claimed effect proposed by the applicant is “contributes to support joint flexibility”. The Panel considers that maintenance of normal joint mobility is a beneficial physiological effect. The applicant identified one human intervention study as being pertinent to the health claim. The Panel notes that chronic inflammation was an inclusion criterion of the study, that a significant number of the patients recruited were reported to have confirmed diagnosis of osteoarthritis, rheumatoid arthritis, or of both cardiovascular disease and osteoarthritis, and that the WOMAC osteoarthritis questionnaire was administered only to patients with arthritic disease (osteoarthritis or rheumatoid arthritis). The Panel also notes that no evidence which could justify the extrapolation of the results, obtained in patients with joint diseases characterised by chronic inflammation, to the target population, subjects without chronic joint diseases, was provided by the applicant. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of EffEXT™ and maintenance of normal joint mobility