Expression of the Aryl Hydrocarbon Receptor in Growth Plate Cartilage and the Impact of Its Local Modulation on Longitudinal Bone Growth

Although dioxin has been reported to impair bone growth in both humans and animals, the underlying mechanisms have not been clarified. We conducted this study to rule out if dioxin may directly target the growth plate, via local modulation of the aryl hydrocarbon receptor (AhR). Initial studies in rare tissue samples of the human growth plate confirmed that the AhR protein is widely expressed in growth plate cartilage. To explore the local role of the AhR, mechanistic studies were performed in a well-established model of cultured fetal rat metatarsal bones. The longitudinal growth of these bones was monitored while being exposed to AhR modulators. The AhR agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin, did not affect bone growth at any concentrations tested (1 pM–10 nM). In contrast, the AhR antagonist, alpha-naphthoflavone, suppressed bone growth and increased chondrocyte apoptosis, although only at a high, potentially cytotoxic concentration (50 µM). We conclude that although the AhR is widely expressed in the growth plate, bone growth is not modulated when locally activated, and therefore, dioxin-induced growth failure is likely mediated through systemic rather than local actions.     

Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

A novel liquid chromatography-mass spectrometry (LC-MS) approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI) coupled to hydrophilic interaction liquid chromatography (HILIC) was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID) fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL) prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.     

How probiotics face food stress: They get by with a little help

Abstract

The dietary consumption of probiotics in the form of pharmaceuticals or functional food can improve human health and contribute to disease prevention. However, the biological activity and health potential of food-delivered probiotics can be severely compromised by the stress conditions encountered by the microorganisms throughout the manufacture process, from probiotic preparation to their inclusion into food, subsequent storage and ingestion. Here, we give an account of the stress factors that can have major negative impacts on probiotic viability and functionality, with a focus on food-related environmental adverse conditions. We also describe some of the mechanisms elicited by the microbial cells to counteract these stresses and summarize a few relevant approaches proposed in literature to develop more robust and competitive probiotics by enhancing their stress tolerance, with the aim to improve the efficacy and health value of probiotic functional food.     

Inactivation of pathogens on pork by steam-ultrasound treatment

The objective of the study was to evaluate a new pathogen inactivation concept that combines application of pressurized steam simultaneously with high-power ultrasound through a series of nozzles. On skin and meat surfaces of pork jowl samples, counts of total viable bacteria were reduced by 1.1 log CFU/cm(2) after treatment for 1 s and by 3.3 log CFU/cm(2) after treatment for 4 s. The mean reduction of 1.7 to 3.3 log CFU/cm(2) on the skin surface was significantly higher than the reduction of 1.1 to 2.5 log CFU/cm(2) on the meat surface. The inactivation of Salmonella Typhimurium, Salmonella Derby, Salmonella Infantis, Yersinia enterocolitica, and a nonpathogenic Escherichia coli was studied on inoculated samples that were treated for 0.5 to 2.0 s. With one exception, no significant differences in reduction were observed among the bacterial types. After treatment for 0.5 s, the 0.9-to 1.5-log reductions of E. coli were significantly higher than the 0.4- to 1.1-log reductions for Salmonella and Y. enterocolitica. Overall, reductions increased by increasing treatment time; reductions were 0.4 to 1.5 log CFU/cm(2) after treatment for 0.5 s and 2.0 to 3.6 log CFU/cm(2) after treatment for 2 s. Reductions on the skin (1 to 3.6 log CFU/cm(2)) were significantly higher than reductions on the meat surface (1 to 2.5 log CFU/cm(2)). The reduced effect on the meat surface may be explained by greater protection of bacteria in deep structures at the muscle surface. No significant difference in reduction was observed between samples inoculated with 10(4) CFU/cm(2) and those inoculated with 10(7) CFU/cm(2), and cold storage of samples for 24 h at 5°C after steam-ultrasound treatment did not lead to changes in recovery of bacteria.     

Photoproduction of H2 by wildtype Anabaena PCC 7120 and a hydrogen uptake deficient mutant: from laboratory experiments to outdoor culture

We have analyzed the filamentous cyanobacterium Anabaena PCC 7120 (wildtype) containing one nitrogenase, one uptake hydrogenase and one bidirectional hydrogenase and its hydrogen uptake deficient mutant AMC 414 for their H₂ production capacities. Anabaena PCC 7120 and AMC 414 had similar growth rates in turbidostat mode with increased growth rates at higher light intensity. Rates of C₂H₂ reduction were similar for both strains. In contrast to the wildtype, AMC 414 produced H₂ in a PhotoBioReactor (PhBR) using air as the lifting gas. The rate of H₂ production increased with light intensity and was not even saturated at 456 μEm⁻² s⁻¹. H₂ production increased significantly when replacing the air with argon. The maximal H₂ production during outdoor conditions was recorded using AMC 414 with a peak at 14.9 ml H₂ h⁻¹ l⁻¹. Despite the relatively high production, maximal efficiency of solar energy to H₂ conversion was only 0.042%. A molecular method was developed to analyze the relative abundancies of weight and mutant in competition experiments in the PhBR.     

Systematic Assessment of Maps as Source Information in Landscape-change Research

A methodology is proposed for systematic map assessment to contribute to landscape-change research. Two major topic areas are dealt with, namely: content, quality and usefulness of landscape information on different maps; and methods used in the spatial conversion of maps into digital systems (e.g. geographical information systems). The major focus is on information about physical landscape characteristics (e.g. land cover) and land uses. The approach was tested using a sequence of nine large- and medium-scale basic maps of the island of Ruissalo in SW Finland from between 1690 and 1998. Fundamental differences were found in the thematic consistency of landscape information, mainly related to the scale, purpose and generalization of landscape information on different maps. Spatial matching was tested for a set of three old maps using four image rectification functions. The results showed that spatial matching of old maps is difficult, and success in rectification is influenced by many factors. Evaluation and selective transformation of landscape information from maps and the use of supportive information from other sources can assist in landscape-change analysis based on map sequences.     

How to create a space for stakeholders’ involvement in construction

The aim is to investigate how stakeholders can participate in the early phases of construction projects and how relevant insights can be gathered from stakeholders with very different backgrounds and interests. To gain these insights, it is important to understand how a space can be created to facilitate communication between professionals and stakeholders. The research draws on the literature of design and user-driven innovation in order to get a richer understanding of stakeholders’ involvement in construction. The method applied is research based on three stakeholder workshops, interviews and observations from a single case study. The findings provide valuable information on six aspects of who the stakeholders are in construction, what these stakeholders can do in construction when involved, how to involve these stakeholders in a construction project, how a space can be staged and facilitated for the meeting of stakeholders, and what kind of information can be collected from the stakeholders to influence the development process. The findings show how creating and facilitating a workshop as a socio-technical space across boundaries can overcome barriers and improve stakeholders’ involvement and thus provide better insights into their needs, values and concerns.     

The occurrence of Listeria monocytogenes in cheese from a manufacturer associated with a case of listeriosis

A case of listeriosis was associated with the consumption of a soft cheese produced in England. Goats cheese and other products from the same food manufacturer were examined for the presence of Listeria over the following 11 months. Listeria monocytogenes was isolated from 16 of 25 cheese samples on retail sale, 12 of 24 cheese samples obtained directly from the factory, and from shelving within the plant. Phage-typing of 68 isolates of L. monocytogenes from cheese samples and the factory showed that 66 (97%) were indistinguishable from the strain isolated from the patient's cerebrospinal fluid and stool. L. monocytogenes was not isolated from seven goats milk or two yoghurt samples. Listeria innocua was isolated from 10 cheese samples, two of which contained no other species of Listeria. Levels of L. monocytogenes shortly after production were low (<10/g), but were higher (10⁵–10⁷ cfu/g) in six of the 16 cheese samples obtained from retail outlets. Multiplication of L. monocytogenes was demonstrated in cheeses contaminated at the factory and held at 4°C in the laboratory.     

Rapid determination of tyramine in fish feed and slaughter offal by HPLC using coulometric detection

Summary Fish feed and slaughter offal products may contain decomposition compounds such as biogenic amines. Owing to their harmful effects on animals fed with such products, there is a need for determing the amine content. In the work a simple and fast HPLC method, based on coulometric detection (EC) measuring only tyramine, was developed for routine quality screening. The samples were extracted with 0.4 mol/L perchloric acid and analysed directly by HPLC using a mobile phase of 0.1 mol/L potassium dihydrogen phosphate in water at pH 3. Tyramine was detected using a coulometric detector consisting of two analytical cells, the first one at 0.4 V and the second at 0.7 V. The calibration was linear over the range 4.52 to 452 ng/ml. The minimum detectable quantity was 10 pg/20111. The reproducibility and the recoveries were high. Comparison of the tyramine content measured by EC or derivatization followed by ultraviolet detection showed that both methods gave similar results. HPLC using EC is a fast and sensitive method for analysing tyramine reliably in fish feed and slaugther offal samples without any time-consuming derivatization steps.

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Schnellbestimmung von Tyramin in Fischfutter und Schlachtabfällen durch HPLC mit coulometrischem Nachweis

Zusammenfassung Fischfutter und Schlachtabfallprodukte können Fäulnisverbindungen wie biogene Amine enthalten. Wegen ihrer schädlichen Wirkung auf Tiere, die damit gefüttert werden, ist es notwendig, auf Amine zu untersuchen. In dieser Arbeit wurde eine einfache und schnelle HPLC-Methode mit coulometrischer Detektion (EC), die nur das Tyrannin mißt, für routinemäßige Qualitätskontrolle entwickelt. Die Muster wurden mit 0,4 mot/L Perchlorsäure extrahiert und unmittelbar durch HPLC analysiert mit einer mobilen Phase von 0,1 mol/L Kaliumdihydrogenphosphat in Wasser bei pH 3. Der coulometrische Detektor besteht aus zwei analytischen Zellen, einer mit 0,4 V und der anderen mit 0,7 V Die Kalibrierung ist linear zwischen 4,52–452 ng/ml. Die geringste feststellbare Menge betrug 10 pg/20 l. Reproduzierbarkeit und Rückgewinnung waren hoch. Der Tyramingehalt, gemessen mit dem coulometrischen Detektor und verglichen mit dem durch Derivatisation nach ultravioletter Detektion erhaltenen, zeigte, daß beide Methoden ähnliche Resultate ergaben. Die entwickelte HPLC-Methode mit ihrer EC-Technik ist eine schnelle und empfindliche Methode zum Analysieren von Tyramin in Fischfutter und Schlachtmustern ohne zeitraubende Stufen der Derivatisation.