Quantification of transmission of livestock-associated methicillin resistant Staphylococcus aureus in pigs

Antimicrobial resistance in pigs becomes a public health issue when resistant organisms transfer from pigs to humans. Pigs are a large reservoir for livestock-associated (LA-)MRSA and people in contact with pigs are at risk for infection with LA-MRSA. Transmission and persistence of LA-MRSA within a pig population contributes to the maintenance of this zoonotic reservoir. Current knowledge on colonization and transmission of LA-MRSA in pigs is limited and mainly based on observational field surveys. Two experiments were performed to colonize pigs and quantify transmission of LA-MRSA between pigs. In the first experiment, colonization of six-week old piglets failed after intranasal inoculation, confirming the complexity of MRSA-colonization. In the second experiment, naive pigs got colonized after exposure to orally inoculated pigs. Subsequently, these contact-infected pigs transmitted MRSA to a new group of naive pigs. The reproduction ratio, R(0), was estimated with a SIS-model to quantify transmission between the first and second contact pigs as this resembles more the natural transmission. Two scenarios were evaluated, with different assumptions regarding infection status of individual pigs. R(0) varied between 3.7 and 4.3 and was significantly above 1, indicating a high probability of persistence of LA-MRSA, even without antimicrobial use.     

Screening for in planta protein-protein interactions combining bimolecular fluorescence complementation with flow cytometry

ABSTRACT: Understanding protein and gene function requires identifying interaction partners usingbiochemical, molecular or genetic tools. In plants, searching for novel protein-proteininteractions is limited to protein purification assays, heterologous in vivo systems such as the yeast-two-hybrid or mutant screens. Ideally one would be able to search for novel proteinpartners in living plant cells. We demonstrate that it is possible to screen for novel proteinproteininteractions from a random library in protoplasted Arabidopsis plant cells and recoversome of the interacting partners. Our screen is based on capturing the bi-molecularcomplementation of mYFP between an YN-bait fusion partner and a completely random preyYC-cDNA library with FACS. The candidate interactions were confirmed using in plantaBiFC assays and in planta FRET-FLIM assays. From this work, we show that the wellcharacterized protein Calcium Dependent Protein Kinase 3 (CPK3) interacts with APX3,HMGB5, ORP2A and a ricin B-related lectin domain containing protein At2g39050. This isone of the first random in planta screens to be successfully employed.     

Occurrence of the Microcystins MC-LW and MC-LF in Dutch Surface Waters and Their Contribution to Total Microcystin Toxicity

Microcystins (MCs) are the most frequently found cyanobacterial toxins in freshwater systems. Many MC variants have been identified and variants differ in their toxicity. Recent studies showed that the variants MC-LW and MC-LF might be more toxic than MC-LR, the variant that is most abundant and mostly used for risk assessments. As little is known about the presence of these two variants in The Netherlands, we determined their occurrence by analyzing 88 water samples and 10 scum samples for eight MC variants ((dm-7-)MC-RR, MC-YR, (dm-7-)MC-LR, MC-LY, MC-LW and MC-LF) by liquid chromatography with tandem mass spectrometry detection. All analyzed MC variants were detected, and MC-LW and/or MC-LF were present in 32% of the MC containing water samples. When MC-LW and MC-LF were present, they contributed to nearly 10% of the total MC concentrations, but due to their suspected high toxicity, their average contribution to the total MC toxicity was estimated to be at least 45%. Given the frequent occurrence and possible high toxicity of MC-LW and MC-LF, it seems better to base health risk assessments on the toxicity contributions of different MC variants than on MC-LR concentrations alone.     

Cellular Antioxidant Effect of Four Bromophenols from the Red Algae,Vertebrata lanosa

Three known bromophenols, 2,3-dibromo-4,5-dihydroxybenzylaldehyde (1), 2,2′,3-tribromo-3′,4,4′,5-tetrahydroxy-6′-hydroxymethyldiphenylmethane (2) and bis(2,3-dibromo-4,5-dihydroxylbenzyl) ether (3), and one new one, 5,5″-oxybis(methylene)bis(3-bromo-4-(2′,3′-dibromo-4′,5′-dihydroxylbenzyl)benzene-1,2-diol) (4), were isolated from an extract of the red alga, Vertebrata lanosa. The antioxidant activity of these four bromophenols was examined using one biochemical and two cellular assays: Oxygen Radical Absorbance Capacity (ORAC), Cellular Antioxidant Activity (CAA) and Cellular Lipid Peroxidation Antioxidant Activity (CLPAA) assays. Compound 2 distinguished itself by showing potent activity, having a better antioxidant effect than luteolin in both the CAA and CLPAA assays and of quercetin in the CLPAA assay. Although several bromophenols are known to be potent antioxidants in biochemical assays, this is the first time their cellular antioxidant activity has been demonstrated.     

The base saturation in acidified Swiss forest soils on calcareous and noncalcareous parent material. A pH–base saturation anomaly

Long‐term soil acidification leads to lower pH values and to a concomitant decrease in base saturation (BS). The relationship between pH and base saturation (BS) in acidified forest soils can be disturbed by processes such as nutrient cycling by vegetation, temporary saturation by ground water that comes into contact with calcareous material, or by upward diffusion of base cations from deeper horizons. This paper examines the relationship between pH and BS in Swiss forest soils developed from calcareous and noncalcareous parent material and identifies some of the factors that can affect the BS in the decalcified parts of soils derived from calcareous parent material. The decalcified zone in the latter soils has a higher BS on average compared to soils from noncalcareous parent material, but their pH values are identical. In the pH range 4.0–4.5, the difference in BS may vary by a factor of three. The mean BS in the decalcified zone tends to decrease with increasing depth of the calcareous layer. The water regime also affects the BS in soils on calcareous parent material. In soils temporarily saturated by groundwater (gleysols), the BS in the decalcified zone is always high (85%–100%) because of the continuous contact between the soil water and the calcareous parent material. In addition, the inhibited drainage impedes the depletion of base cations in these soils. In contrast, soils that are temporarily saturated by rainwater are depleted in base cations due to the alternating wetting‐and‐drying regime and the associated leaching of dissolved ions. In such soils, the depletion of base cations is strongly related to the extent of hydromorphy. Stagnogleyic soils, with the longest period of water saturation, have the highest depletion levels. We conclude that in such soils, the diffusion of base cations from deeper zones is strongly compensated by leaching from the very acidic soil horizons. The pH–base saturation anomaly has consequences for some of the methods used to calculate the critical loads of acidity for forest soils in Switzerland, with many soils being less sensitive than previously reported.     

Impact of the earthworm Lumbricus terrestris on the degradation of Fusarium-infected and deoxynivalenol-contaminated wheat straw

When conservation tillage is practised in agriculture, plant residues remain on the soil surface for soil protection purposes. These residues should be widely decomposed within the following vegetation period as microbial plant pathogens surviving on plant litter may endanger the currently cultivated crop. Important soil-borne fungal pathogens that preferably infect small grain cereals belong to the genus Fusarium. These pathogens produce the mycotoxin deoxynivalenol (DON), a cytotoxic agent, in infected cereal organs. This toxin frequently occurs in cereal residues like straw. So far it is unclear if DON degradation is affected by members of the soil food web within decomposing processes in the soil system. For this purpose, a microcosm study was conducted under controlled laboratory conditions to investigate the degradation activity of the earthworm species Lumbricus terrestris when exposed to Fusarium-infected wheat straw being contaminated with DON.Highly Fusarium-infected and DON-contaminated straw seemed to be more attractive to L. terrestris because it was incorporated faster into the soil compared with straw infected and contaminated at low levels. This is supported by a greater body weight gain (exposure time 5 weeks) and smaller body weight loss (exposure time 11 weeks) of L. terrestris, respectively, when highly contaminated straw was offered for different time periods.Furthermore, L. terrestris takes part in the efficient degradation of both Fusarium biomass and DON occurring in straw in close interaction with soil microorganisms. Consequently, earthworm activity contributes to the elimination of potentially infectious plant material from the soil surface.     

Quantification of heterocyclic aromatic amines in fried meat by HPTLC/UV-FLD and HPLC/UV-FLD: a comparison of two methods

A recently developed HPTLC/UV-FLD method was compared to the routinely used HPLC/UV-FLD method for the quantification of heterocyclic aromatic amines (HAA) formed at trace levels during the heating process of meat. For formation of these process contaminants under normal cooking conditions, beef patties were fried in a double-contact grill at 230 degrees C for five different frying times and extracted by solid-phase extraction. The HAAs most frequently found, that is, 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5- f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5- f]quinoxaline (4,8-DiMeIQx), 9 H-pyrido[3,4- b]indole (norharman), and 1-methyl-9 H-pyrido[3,4- b]indole (harman), were quantified by two chromatographic methods, which were orthogonal to each other (normal versus reversed phase system). Both methods showed a similar performance and good correlation of the results ( R (2) between 0.8875 and 0.9751). The comparison of running costs and run time in routine analysis proved HPTLC/UV-FLD to be more economical (factor of 3) and faster (factor of 4) due to its capability of parallel chromatography. The HAA findings calculated by standard addition increased with the heating time from <1 to 33 microg/kg related to 3-6 min of frying time. The precision (RSD) was between 7 and 49% (HPTLC) and between 5 and 38% (HPLC) at these very low HAA levels formed.     

Effects of dietary L‐arginine supplementation to early pregnant mares on conceptus diameter—Preliminary findings

The importance of the amino acid L‐arginine (ARG) for conceptus growth and litter size has been demonstrated in various species. L‐arginine is part of embryo‐derived polyamines, a substrate for nitric oxide synthase and stimulates protein synthesis by the embryo. In the present study, we have investigated whether dietary L‐arginine supplementation stimulates early conceptus growth in mares. Warmblood mares with singleton pregnancies received either an arginine‐supplemented diet (approximately 0.0125% of body weight, n = 12) or a control diet (n = 11) from days 15 to 45 after ovulation. Diameter of the embryonic vesicle (days 14, 17, 20 of pregnancy) and size of the embryo respective foetus (length and maximal diameter, days 25–45 of pregnancy at 5‐day intervals) were determined by transrectal ultrasound. At foaling, weight and size of the foal and the placenta were determined. Blood for determination of equine chorionic gonadotrophin (eCG) and progestin concentrations was collected repeatedly. Neither eCG nor progestin concentration in plasma of mares differed between groups at any time. No effects of arginine treatment on diameter of the embryonic vesicle between days 14 and 20 of pregnancy were detected. Diameter of the embryo/foetus on days 40 to 45 of pregnancy strongly tended to be enhanced by arginine supplementation (p = 0.06). Weight and size of neither the foal nor placenta at birth differed between groups. In conclusion, L‐arginine supplementation was without negative effects on early equine embryos and may support embryonic growth at the beginning of placentation.     

Einfluss von Unterlagen im Vergleich zu selbstbewurzelten Birnenbäumen auf vegetative und generative Parameter unter biologischen Anbaubedingungen in Ostösterreich

In spring 2006, in the research center of the University of Natural Resources and Life Sciences in Vienna, the pear cultivars ‘Bosc’s’, ‘Williams’ Christ’ and ‘Uta’ were planted on the rootstocks Kirchensaller Mostbirne (Seedling), Pyrodwarf, Farold 69, Quince Adams (with intercropping ‘Conference’) and own-rooted from in vitro culture, trained as spindles and tested for eight years under organic production rules. The own-rooted ‘Williams’- and ‘Bosc’s’-trees had many tree losses in the first year, they grew medium and started with fruiting later than the grafted trees. The trees on rootstock Quince Adams were growing very weakly in the high lime containing soil at the site, with the consequence of chlorosis, tree losses and small fruits, but also a higher brix-, vitamin C- and apple acid-content in the fruits. ‘Bosc’s’ showed low yields on all rootstocks in the observing period. ‘Williams’ on Farold 69 and Seedling had good yield and fruit quality, while the weakly growing cultivar ‘Uta’ showed low tree losses and high yields on Seedling. Pyrodwarf had very few tree losses and was similar in growth and yield compared to Farold 69 and Seedling, however the fruits of ‘Williams’ and ‘Bosc’s’ were smaller.     

Toxoplasma gondii and ovine toxoplasmosis: new aspects of an old story

Ovine toxoplasmosis, caused by the intracellular protozoan parasite Toxoplasma gondii, was first described in 1954 and while the incidence of ovine infection is difficult to define, it has been reported that in the UK it is responsible for between 1 and 2% of neonatal losses per annum. Recent reports have suggested that sheep persistently infected with T. gondii may pass infection to the fetus in subsequent pregnancies more readily than previously thought. These data show a high proportion of both successful and failed pregnancies in sheep to be positive by PCR for T. gondii with a tendency for samples from certain genetic lines of Charollais sheep more likely to be positive than samples from other lines, suggesting that some sheep have a particular genetic susceptibility to T. gondii.