Similar Listeria monocytogenes pulsotypes detected in several foods originating from different sources

The purpose of the study was to obtain fingerprinting data of Listeria monocytogenes strains isolated in various foods to determine possible associations of strains with product type, producer, country or isolation time. Two hundred and ninety-five L. monocytogenes strains originating from food items of 41 producers of 10 countries were characterized by pulsed-field gel electrophoresis (PFGE) typing. Combination of AscI and ApaI macrorestriction patterns (MRP) yielded 66 different pulsotypes. Ten pulsotypes were common to two or more product types and 17 pulsotypes were detected in foods of more than one producer having no apparent association with each other. Similar pulsotypes of L. monocytogenes were recovered in products of different countries over several years. Some of the pulsotypes were recurrently recovered from the same product of the same producer, suggesting a possible persistence of these strains in the processing plant. However, some of the recurrently isolated L. monocytogenes pulsotypes were repeatedly found in products of several producers, which may indicate that persistent houseflora strains are not always producer-specific. Furthermore, the similarity of macrorestriction patterns expressed as clusters, based on the numerical analysis of macrorestriction patterns, was not found to correlate with product type, country, producer or year of isolation. Our data suggest a wide geographical and temporal distribution of a number of L. monocytogenes strains isolated in food products. The existence of similar L. monocytogenes strains in various food products of several producers should be considered if food strain fingerprint results are used to help trace the vehicles for infections.     

Rhizosphere characteristics of the arsenic hyperaccumulator Pteris vittata L. and monitoring of phytoremoval efficiency

Recently discovered As-hyperaccumulator ferns hold promise for phytoremediation of As-polluted soils. We investigated changes in the rhizosphere characteristics of Pteris vittata (Chinese Brake fern) relevant for its use in phytoextraction. Plants were grown in rhizoboxes filled with soil containing 2270 mg kg(-1) As. Dissolved organic carbon (DOC) concentrations in rhizosphere soil solution were increased by 86% and appeared to enhance total Fe solubility due to complexation reactions. Despite substantial removal of As by the fern, As was not significantly decreased in the rhizsophere soil solution after one cropping, apparently due to the large buffer capacity of the soil and possibly because of ion competition with DOC. However, the difference between 0.05 M (NH4)2SO4-extractable labile As in bulk and rhizosphere soil accounted for 8.9% of total As accumulated in the fern, indicating that As was mainly acquired from less available pools. Moreover, As depletion in the rhizosphere and limited resupply from less available pools were indicated by a 19.3% decreased As flux, measured using the technique of diffusive gradients in thin films (DGT). Modeling of the DGT-soil system was able to show that the rate of release from solid phase to solution in the rhizosphere was one-third of that in the bulk soil. Applying the remedial strategy of bioavailable contaminant stripping, which aims at diminishing the phytoavailable pollutant fraction, DGT can be used as a monitoring tool to evaluate the efficiency of phytoextraction and to study the potential resupply of bioavailable pools after phytoextraction has ceased.     

Photoirradiation of dissolved humic acid induces arsenic(III) oxidation

The fate of arsenic in aquatic systems is influenced by dissolved natural organic matter (DOM). Using UV-A and visible light from a medium-pressure mercury lamp, the photosensitized oxidation of As(III) to As(V) in the presence of Suwannee River humic acid was investigated. Pseudo-first-order kinetics was observed. For 5 mg L(-1) of dissolved organic carbon (DOC) and 1.85 mEinstein m(-2) s(-1) UV-A fluence rate, the rate coefficient k degrees exp was 21.2 +/- 3.2 10(-5) s(-1), corresponding to a half-life <1 h. Rates increased linearly with DOC and they increased by a factor of 10 from pH 4 to 8. Based on experiments with radical scavengers, heavy water, and surrogates for DOM, excited triplet states and/or phenoxyl radicals seem to be important photooxidants in this system (rather than singlet oxygen, hydrogen peroxide, hydroxyl radicals, and superoxide). Photoirradiation of natural samples from freshwater lakes, rivers, and rice field water (Bangladesh) showed similar photoinduced oxidation rates based on DOC. Fe(III) (as polynuclear Fe(III)-(hydr)oxo complexes or Fe(III)-DOC complexes) accelerates the rate of photoinduced As(III) oxidation in the presence of DOC by a factor of 1.5-2.     

Effects of ellagitannin‐rich berries on blood lipids,gut microbiota,and urolithin production in human subjects with symptoms of metabolic syndrome

Ellagitannins are polyphenols abundant in strawberries, raspberries, and cloudberries. The effects of a mixture of these berries were studied in a randomized controlled trial with subjects having symptoms of metabolic syndrome. The study focused on serum lipid profiles, gut microbiota, and ellagitannin metabolites. The results indicate that bioavailability of ellagitannins appears to be dependent on the composition of gut microbiota.     

The Influence of Nanoparticle Shape on Protein Corona Formation

Nanoparticles have become an important utility in many areas of medical treatment such as targeted drug and treatment delivery as well as imaging and diagnostics. These advances require a complete understanding of nanoparticles' fate once placed in the body. Upon exposure to blood, proteins adsorb onto the nanoparticles surface and form a protein corona, which determines the particles' biological fate. This study reports on the protein corona formation from blood serum and plasma on spherical and rod‐shaped nanoparticles. These two types of mesoporous silica nanoparticles have identical chemistry, porosity, surface potential, and size in the y‐dimension, one being a sphere and the other a rod shape. The results show a significantly larger amount of protein attaching from both plasma and serum on the rod‐like particles compared to the spheres. Interrogation of the protein corona by liquid chromatography–mass spectrometry reveals shape‐dependent differences in the adsorption of immunoglobulins and albumin proteins from both plasma and serum. This study points to the need for taking nanoparticle shape into consideration because it can have a significant impact on the fate and therapeutic potential of nanoparticles when placed in the body.     

Pododermal angiogenesis and angioadaptation in the bovine claw

Pododermal microvascularization has been suggested to play a key role in the physiological function of the bovine claw and in the pathogenesis of claw diseases. According to our working hypothesis, angiogenesis plays a central role in the physiological and pathological function of the claw and is induced by the pro-angiogenic vascular endothelial growth factor (VEGF). As a basis for further research, the aim of the present study was to examine the mechanisms of pododermal angiogenesis in the functional adaptation of the microvasculature of the claw in histological serial sections and microcorrosion casts of healthy juvenile and adult claws as well as pathologically altered claws. Scanning electron microscopy of microcorrosion casts allowed assessment of the 3D aspect of pododermal angiogenesis and angioadaptation, and was substantiated by a concomitant examination of a 3D in vitro model of angiogenesis based on cultured bovine microvascular endothelial cells. Particularly in the juvenile, but also in the adult claw, sprouting and intussusceptive angioadaptation was demonstrated and resembled the respective stages of in vitro angiogenesis. Evidence of angiogenic processes was also detected in the pathologically altered claws displaying symptoms of subclinical laminitis and/or the digital dermatitis complex. The detected angioadaptation was visible expression of the increased metabolic demands of the claw caused by the growing body weight load. Angiogenic remodeling of the pododermal angioarchitecture was also the connectional reparative principle in pathologically altered claws. Related research perspectives for prophylaxis and therapy of claw diseases are discussed.     

In Situ Electrical Characterization of Anatase TiO2 Quantum Dots

A novel method for performing in situ characterization of the electrical properties of pristine, ultrafine nanopowders is reported. A modified dilatometer, with a spring‐loaded push rod and electrodes, allows for the simultaneous monitoring of the packed nanopowder's lateral displacement as well as its complex impedance spectroscopy as a function of temperature within a controlled environment. Anatase TiO₂ quantum dots of 2 nm diameter, on average, are examined and found to simultaneously shrink and become more resistive upon initial heating. The resistance changes by approximately 3 orders of magnitude upon heating, associated with the desorption of adsorbed water, demonstrating the need for sample preconditioning. Subsequent electrical resistivity measurements, as a function of oxygen partial pressure, over approximately 40 orders of magnitude, at temperatures between 300 °C and 400 °C, exhibit nearly 9 orders of magnitude change in conductivity. The data are consistent with a Frenkel‐based defect disorder model characterized by an enthalpy of reduction of 5.5 ± 0.5 eV.     

Pushing Boundaries—Selective Cooling Crystallization as Tool for Selectivity Compensation and Product Purification Using a Recyclable Pd/Xantphos Catalyst in the Methoxycarbonylation of Methyl 10-Undecenoate

The homogeneously catalyzed methoxycarbonylation of methyl 10-undecenoate allows for the synthesis of dimethyl 1,12-dodecandioate as an interesting bio-based drop-in alternative for 1,12-dodecandioic acid as polymer building block. Although the benchmark catalyst system of Pd/1,2-bis((di-tert-butylphosphino)methyl)benzene and methane sulfonic acid is very active and selective, long-term stability over a potential catalyst recycling is limited. In this work, modifications of this catalyst system in terms of protonation of the ligand and its replenishment during recycling are first investigated, proving that the reaction system is tolerant against minor changes. Finally, the commercially available ligand Xantphos, featuring higher stability but comes with a rather low l:b selectivity of 70:30, is applied. However, through the application of cooling crystallization, 58 g product (52% isolated yield) with an overall purity of 94% is obtained from the crude reaction solution without further treatment and a ∑TON of 4000 after ten reaction runs, while catalyst loss into the product is low. Practical Applications: Selective syntheses on the basis of renewable resources are a powerful tool for the production of value products in terms of green chemistry. Thereby, homogeneous transition metal catalysts are beneficial regarding selectivity. However, their separation and recycling are challenging due to their limited stability. The combination of a stable, commercially available catalyst with a selective purification method allows for isolation and purification from a crude reaction mixture without the need for any auxiliary or further purification steps. In this work, cooling crystallization is applied for subsequent purification of the linear diester dimethyl 1,12-dodecandioate. Thereby, a lower selectivity from the methoxycarbonylation reaction using the stable Xantphos ligand is compensated and combined with recycling of the homogeneous catalyst. Thus, the development of an integrated process covering a stable catalyst system in the reaction, and high selectivity in the purification is the key toward an efficient homogeneous catalyst recycling.     

Replacing human-edible feed ingredients with by-products increases net food production efficiency in dairy cows

Global demand for food is increasing, and use of large amounts of potentially human-edible feedstuffs for dairy cows is an important concern. The present study examined whether feeding a by-product-based concentrate combined with high-quality grass silage to high-producing dairy cows affected feed intake and milk production compared with a conventional diet, as well as the effect on efficiency of human food production. In a changeover experiment with four 21-d periods, 24 dairy cows in mid-lactation were offered 9.6 kg of dry matter per day with 1 of 4 concentrates and high-quality grass silage ad libitum. The control concentrate was based on cereal grain (wheat, oat, and barley) and soybean meal, whereas the 3 by-product-based concentrates contained sugar beet pulp in combination with mainly heat-treated rapeseed meal, distillers grain, or a mixture of both. All diets were formulated to be isoenergetic and isonitrogenous. The cows had 10-fold higher starch intake when fed the control diet than when fed the by-product-based concentrates. Silage intake (13 kg of dry matter/d) and milk production (33 kg of energy-corrected milk/d) were not affected by the change in diet. Therefore, replacing cereals and soybean meal with human-inedible by-products in a high-quality forage diet to dairy cows increased net food protein production substantially without lowering milk production.