A rapid optical immunoassay for the screening of T-2 and HT-2 toxin in cereals and maize-based baby food

A rapid surface plasmon resonance (SPR) screening assay has been developed for the combined detection of T-2 and HT-2 toxins in naturally contaminated cereals using a sensor chip coated with an HT-2 toxin derivative and a monoclonal antibody. The antibody raised against HT-2 displayed high cross-reactivity with T-2 toxin while there was no cross-reaction observed with other commonly occurring trichothecenes. A simple extraction procedure using 40% methanol was applied to baby food, breakfast cereal, and wheat samples prior to biosensor analysis. Limits of detection (LOD) for each matrix were determined as 25 mu g kg(-1) for baby food and breakfast cereal and 26 mu g kg(-1) for wheat. Intra-assay precision (n = 6) was calculated for each matrix. The results were expressed as the relative standard deviation and determined as 2.8% (100 mu g kg(-1)) and 1.8% (200 mu g kg(-1)) in breakfast cereal, 4.6% (50 mu g kg(-1)) and 3.6% (100 mu g kg(-1)) in wheat and 0.97% (25 mu g kg(-1)) and 6.3% (50 mu g kg(-1)) in baby food. Between run precision (n = 3) performed at the same levels yielded relative standard deviations of 6.7% and 3.9% for breakfast cereals, 3.3% and 1.6% for wheat and 6.8% and 0.08% for baby food, respectively. (C) 2010 Elsevier B.V. All rights reserved.

Dinoflagellate cyst-based reconstructions of mid to late Holocene winter sea-surface temperature and productivity from an anoxic fjord in the NE Pacific Ocean

Published contemporary dinoflagellate distributional data from the NE Pacific margin and estuarine environments (n = 136) were re-analyzed using Canonical Correspondence Analysis (CCA) and partial Canonical Correspondence Analysis (pCCA). These analyses illustrated the dominant controls of winter temperature and productivity on the distribution of dinoflagellate cysts in this region. Dinoflagellate cyst-based predictive models for winter temperature and productivity were developed from the contemporary distributional data using the modern analogue technique and applied to subfossil data from two mid to late Holocene (~5500 calendar years before present–present) cores; TUL99B03 and TUL99B11, collected from Effingham Inlet, a 15 km long anoxic fjord located on the southwest coast of Vancouver Island that directly opens to the Pacific Ocean through Barkley Sound. Sedimentation within these basins largely comprises annually deposited laminated couplets, each made up of a winter deposited terrigenous layer and spring to fall deposited diatomaceous layer. The Effingham Inlet dinoflagellate cyst record provides evidence of a mid-Holocene gradual decline in winter SST, ending with the initiation of neoglacial advances in the region by ~3500 cal BP. A reconstructed Late Holocene increase in winter SST was initiated by a weakening of the California Current, which would have resulted in a warmer central gyre and more El Niño-like conditions.

A comparative study of qualitative immunochemical screening assays for the combined measurement of T-2/HT-2 in cereals and cereal-based products

Many different immunochemical platforms exist for the screening of naturally occurring contaminants in food from the low cost enzyme linked immunosorbent assays (ELISA) to the expensive instruments such as optical biosensors based on the phenomenon of surface plasmon resonance (SPR). The primary aim of this study was to evaluate and compare a number of these platforms to assess their accuracy and precision when applied to naturally contaminated samples containing HT-2/T-2 mycotoxins. Other important factors considered were the speed of analysis, ease of use (sample preparation techniques and use of the equipment) and ultimately the cost implications. The three screening procedures compared included an SPR biosensor assay, a commercially available ELISA and an enzyme-linked immunomagnetic electrochemical array (ELIME array). The qualitative data for all methods demonstrated very good overall agreements with each other, however on comparison with mass spectrometry confirmatory results, the ELISA and SPR assay performed slightly better than the ELIME array, exhibiting an overall agreement of 95.8% compared to 91.7%. Currently, SPR is more costly than the other two platforms and can only be used in the laboratory whereas in theory both the ELISA and ELIME array are portable and can be used in the field, but ultimately this is dependent on the sample preparation techniques employed. Sample preparative techniques varied for all methods evaluated, the ELISA was the most simple to perform followed by that of the SPR method. The ELIME array involved an additional clean-up step thereby increasing both the time and cost of analysis. Therefore in the current format, field use would not be an option for the ELIME array. In relation to speed of analysis, the ELISA outperformed the other methods.

Survey of arsenic and its speciation in rice products such as breakfast cereals, rice crackers and Japanese rice condiments

Rice has been demonstrated to be one of the major contributors to arsenic (As) in human diets in addition to drinking water, but little is known about rice products as an additional source of As exposure. Rice products were analyzed for total As and a subset of samples were measured for arsenic speciation using high performance liquid chromatography interfaced with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). A wide range of rice products had total and inorganic arsenic levels that typified those found in rice grain including, crisped rice, puffed rice, rice crackers, rice noodles and a range of Japanese rice condiments as well as rice products targeted at the macrobiotic, vegan, lactose intolerant and gluten intolerance food market. Most As in rice products are inorganic As (75.2-90.1%). This study provides a wider appreciation of how inorganic arsenic derived from rice products enters the human diet. (C) 2008 Elsevier Ltd. All rights reserved.

The effects of winter ice cover on the trophic ecology of whitefish (Coregonus lavaretus L.) in subarctic lakes

Lakes in Arctic and subarctic regions display extreme levels of seasonal variation in light, temperature and ice cover. Comparatively little is known regarding the effects of such seasonal variation on the diet and resource use of fish species inhabiting these systems. Variation in the diet of European whitefish Coregonus lavaretus (L.) during periods of ice cover in this region is often regarded as 'common knowledge'; however, this aspect of the species' ecology has not been examined empirically. Here, we outline the differences in invertebrate community structure, fish activity, and resource use of monomorphic whitefish populations between summer (August-September) and winter (February-March) in three subarctic lakes in Finnish Lapland. Benthic macroinvertebrate densities did not exhibit measurable differences between summer and winter. Zooplankton diversity and abundance, and activity levels of all fish species (measured as catch per unit effort) were lower in winter. The summer diet of C. lavaretus was typical of a generalist utilising a variety of prey sources. In winter, its dietary niche was significantly reduced, and the diet was dominated by chironomid larvae in all study sites. Pelagic productivity decreases during winter, and fish species inhabiting these systems are therefore restricted to feeding on benthic prey. Sampling time has strong effect on our understanding of resource utilisation by whitefish in subarctic lakes and should be taken into account in future studies of these systems. © 2012 John Wiley & Sons A/S.

Wind generation and electricity demand during the severe winter of 2009/10 in Ireland

Throughout the world the share of wind power in the generation mix is increasing. In the All Island Grid, of the Republic of Ireland and Northern Ireland there is now over 1.5 GW of installed wind power. As the penetration of these variable, non-dispatchable generators increases, power systems are becoming more sensitive to weather events on the supply side as well as on the demand side. In the temperate climate of Ireland, sensitivity of supply to weather is mainly due to wind variability while demand sensitivity is driven by space heating or cooling loads. The interplay of these two weather-driven effects is of particular concern if demand spikes driven by low temperatures coincide with periods of low winds. In December 2009 and January 2010 Ireland experienced a prolonged spell of unusually cold conditions. During much of this time, wind generation output was low due to low wind speeds. The impacts of this event are presented as a case study of the effects of weather extremes on power systems with high penetrations of variable renewable generation.

Influence of tropical easterlies in southern Africa's winter rainfall zone during the Holocene

South Africa's southwestern Cape occupies a critical transition zone between Southern Hemisphere temperate (winter) and tropical (summer) moisture-bearing systems. In the recent geological past, it has been proposed that the relative influence of these systems may have changed substantially, but little reliable evidence regarding regional hydroclimates and rainfall seasonality exists to refine or substantiate the understanding of long-term dynamics. In this paper we present a mid-to late Holocene multi-proxy record of environmental change from a rock hyrax midden from Katbakkies Pass, located along the modern boundary between the winter and summer rainfall zones. Derived from stable carbon and nitrogen isotopes, fossil pollen and microcharcoal, these data provide a high resolution record of changes in humidity, and insight into changes in rainfall seasonality. Whereas previous work concluded that the site had generally experienced only subtle environmental change during the Holocene, our records indicate that significant, abrupt changes have occurred in the region over the last 7000 years. Contrary to expectations based on the site's location, these data indicate that the primary determinant of changes in humidity is summer rather than winter rainfall variability, and its influence on drought season intensity and/or length. These findings are consistent with independent records of upwelling along the southern and western coasts, which indicate that periods of increased humidity are related to increased tropical easterly flow. This substantially refines our understanding of the nature of temperate and tropical circulation system dynamics in SW Africa, and how changes in their relative dominance have impacted regional environments during the Holocene. 

Winter Is Coming: Seasonal Variation in Resting Metabolic Rate of the European Badger (Meles meles)

Resting metabolic rate (RMR) is a measure of the minimum energy requirements of an animal at rest, and can give an indication of the costs of somatic maintenance. We measured RMR of free-ranging European badgers (Meles meles) to determine whether differences were related to sex, age and season. Badgers were captured in live-traps and placed individually within a metabolic chamber maintained at 20 ± 1°C. Resting metabolic rate was determined using an open-circuit respirometry system. Season was significantly correlated with RMR, but no effects of age or sex were detected. Summer RMR values were significantly higher than winter values (mass-adjusted mean ± standard error: 2366 ± 70 kJ⋅d-1; 1845 ± 109 kJ⋅d-1, respectively), with the percentage difference being 24.7%. While under the influence of anaesthesia, RMR was estimated to be 25.5% lower than the combined average value before administration, and after recovery from anaesthesia. Resting metabolic rate during the autumn and winter was not significantly different to allometric predictions of basal metabolic rate for mustelid species weighing 1 kg or greater, but badgers measured in the summer had values that were higher than predicted. Results suggest that a seasonal reduction in RMR coincides with apparent reductions in physical activity and body temperature as part of the overwintering strategy ('winter lethargy') in badgers. This study contributes to an expanding dataset on the ecophysiology of medium-sized carnivores, and emphasises the importance of considering season when making predictions of metabolic rate.