Size heterogeneity, growth potential and aggression in juvenile yellowtail kingfish (Seriola lalandi Valenciennes)

The ontogenetic development of size heterogeneity and aggression was monitored in commercial culture tanks of yellowtail kingfish (Seriola lalandi Valenciennes). Size heterogeneity increased substantially with the introduction of Artemia as a food source at 12 days post‐hatch (DPH), and was correlated with the appearance of aiming behaviour, a precursor to more direct aggressive interactions. Chasing behaviour started at approximately 19 DPH (10–12 mm total length), with the main aggressors being large‐grade individuals comprising 8% of the population. At any one time, only 10–30% of this grade carried out all of the chases, meaning that a very small proportion of the entire population (1%) was responsible for most of the aggressive interactions. The main recipients of aggression were the small grade, comprising 42% of the population, while the medium grade (50% of the population) were generally not aggressive and received only a low to moderate level of aggression. A grading trial showed that large‐grade juveniles only displayed aggressive behaviour in the presence of size heterogeneity, and that medium‐ or small‐grade juveniles did not establish an agonistic hierarchy in the absence of large individuals. A high level of aggression in the ungraded control treatment was associated with mortality of most of the small individuals. Even in the absence of aggression, the small‐grade juveniles failed to gain weight or show an increase in the RNA/DNA ratio after 12 days. The large‐ and medium‐grade larvae showed an isometric increase in RNA/DNA ratio during development, indicating that faster‐growing individuals are likely the result of better food capture or processing traits rather than better protein synthesis rates. Decreasing size heterogeneity and aggression via grading mostly benefits the medium‐grade individuals, as the majority of small individuals within a batch appear to be on a degenerative developmental trajectory irrespective of an aggressive environment.     

Proton transfer reaction mass spectrometry and time intensity perceptual measurement of flavor release from lipid emulsions using trained human subjects

The effect of the fat component of liquid emulsions on dynamic "in-nose" flavor release was examined using a panel of trained human subjects (n = 6), proton transfer reaction mass spectrometry (PTR-MS), and time intensity (TI) sensory evaluation. A rigorous breathing and consumption protocol was developed, which synchronized subjects' breathing cycles and also the timing of sample introduction. Temporal changes in volatile release were measured in exhaled nostril breath by real-time PTR-MS. Corresponding changes in the perceived odor intensity could also be simultaneously measured using a push button TI device. The method facilitated accurate examination of both "preswallow" and "postswallow" phases of volatile release and perception. Volatile flavor compounds spanning a range of octanol/water partition coefficient (K(o/w)) values (1-1380) were spiked into water (0% fat) or lipid emulsions with various fat contents (2, 5, 10, and 20% fat). Replicate samples for each fat level were consumed according to the consumption protocol by six subjects. Statistical comparisons were made at the individual level and across the group for the effects of changes in the food matrix, such as fat content, on both pre- and postswallow volatile release. Significant group differences in volatile release parameters including area under the concentration curve (AUC) and maximum concentration (I(max)) were measured according to the lipid content of emulsions and volatile K(o/w). In a second experiment, using single compounds (2-heptanone, ethyl butanoate, and ethyl hexanoate), significant decreases in both in-nose volatile release and corresponding perceived odor intensities were measured with increasing fat addition. Overall, the effect of fat on in vivo release conformed to theory; fat had little effect on compounds with low K(o/w) values, but increased for volatiles with higher lipophilicity. In addition, significant pre- and postswallow differences were observed in AUC and I(max), as a result of changing fat levels. In the absence of fat, more than half of the total amount of volatile was released in the preswallow phase. As the content of fat was increased in the emulsion systems, the ratio of volatile released postswallow increased compared to preswallow. These data may provide new insights into why low-fat and high-fat foods are perceived differently.     

Effects of Short-term Heating on Total Polyphenols,Anthocyanins, Antioxidant Activity and Lectins of Different Parts of Dwarf Elder (Sambucus ebulus L.)

Dwarf elder (Sambucus ebulus L.) berries are rich in health-promoting phytochemicals such as polyphenols and anthocyanins, and display a significant antioxidant activity. They are also rich in two lectins (ebulin f and SELfd) that share amino acid sequence homology with the elderberry allergen Sam n1 present in Sambucus nigra pollen and fruits. Ebulin f displays toxicity by oral ingestion. This study was aimed at eliminating the toxicity of these lectins whilst having little or no effect on the antioxidant properties of dwarf elder berries. We thus investigated the potential effects of incubation in a boiling water bath of extracts from several parts of the plant on total polyphenol content, antioxidant activity, total anthocyanins, cyanidin-3-glycoside content, and the sensitivity of purified dwarf elder fruit lectins to a simulated gastric fluid. The study shows that five minutes of said heat treatment fully sensitized both lectins to pepsin digestion, whilst minimally reducing phenol and antioxidant as well as free radical scavenging activities to below 13 %. It proved possible to eliminate the potential risks derived from the presence of lectins in dwarf elder juices without any significant reduction in the content of the antioxidant compounds. Dwarf elder berries may thus be a valuable nutritional source.     

Substance Flow Analysis of Mercury Affecting Water Quality in the European Union

Knowledge concerning the main flows of priority substances (PSs) and the production systems and consumption structures in the society causing these flows is a prerequisite for any attempt to predict and understand their environmental fate as well as to efficiently minimize future environmental burdens. In this paper, a simple SFA diagram on mercury, including the main European Union (EU-27) source categories, flows and environmental endpoints which in turn affect the mercury concentrations in the EU-27 waters are illustrated. From trend analysis and future projections, it becomes obvious that emissions of mercury as a trace contaminant in fuels and minerals (primary anthropogenic emission sources) are becoming increasingly important to the environmental concentrations compared to emissions from mercury used intentionally (secondary anthropogenic sources). Additional future control strategies should therefore be targeted industrial sources and safe treatment of mercury-containing wastes, wastewater effluents, as well as residues collected from various combustion processes. It was found that knowledge on flows and emission sources on a large geographical scale is limited due to a lack of information on emission factors from various industrial processes and waste systems, especially for the mercury being discharges to water and land.     

An invertebrate harmfulness scale for research on plant pest diversity and impacts

Traditional methods of quantifying the harmful effects of invertebrates on plants require time-consuming identification of large numbers of individuals at species level. Collected specimens usually are killed; this may be unacceptable for some strictly protected species and may bias the results of subsequent surveys at the same site.

We developed a “harmfulness scale” for quick, non-invasive assessment of invertebrate impacts on plants, and used the scale to test differences in invertebrate attack on species of Balsaminaceae, Polygonaceae and Asteraceae growing in lowland and mountains in Poland. In 2010–2011, we recorded 9190 invertebrates and identified them in situ to family or superfamily level. Among them were 7593 pests, accounting for 82.6% of all recorded organisms. Pests were three times more numerous in the mountains than in the lowland. Balsaminaceae were most heavily attacked by pests (92.9% of all organisms detected on them). Aphidoideae were the most numerous pests.

This method can help reduce the costs and labour required for this type of research, facilitating progress in theoretical biology and in the development of practical phytosanitary measures.     

Management of laurel wilt of avocado,caused by <Emphasis Type="Italic">Raffaelea lauricola</Emphasis>

Laurel wilt is caused by Raffaelea lauricola, a nutritional symbiont of an Asian ambrosia beetle, Xyleborus glabratus. American members of the Lauraceae plant family are most susceptible and 300 million trees have been killed by the disease in the southeastern USA since 2003. Recently, commercial production of an important crop in the laurel family, avocado (Persea americana), has been affected in southern Florida. We summarize studies in which diverse measures were tested for managing the disease. In all studies, trees were treated with potential laurel wilt control measures and subsequently inoculated with R. lauricola. On potted plants in greenhouse experiments, commercial nutritional products (Greenstim and Keyplex 350) and SAR products (Agri-Fos and Nutri-Phite), when applied as soil drenches or foliar sprays, had either no impact on, or increased laurel wilt symptom development compared to non-treated control treatments. Bark applications of Tilt (a propiconazole fungicide for which emergency registration had been obtained in 2010) in a surfactant (Pentrabark) enabled significant laurel wilt protection in greenhouse studies on small potted plants, but Pentrabark and other surfactants moved little propiconazole into the xylem of fruit-bearing trees in field studies. In efficacy studies in the field, Propiconazole Pro (an injectable formulation of propiconazole), Tilt, and two experimental formulations of another triazole fungicide, tebuconazole, decreased the development of laurel wilt compared to nontreated control trees when applied as undiluted injections into branches and scaffold limbs (microinjection), or injection of dilute fungicide into tree flare roots (macroinfusion). However, symptoms developed in all treated trees by 10–11 months after inoculation with R. lauricola, indicating that trees would need to be re-treated at least on an annual basis. Regardless of how fungicides were applied, insignificant levels of different active ingredients entered fruit. Although fungicide treatment of fruit-bearing avocado trees is not a concern for food safety and several triazole and DMI fungicides can protect avocado trees from laurel wilt, cost-effective measures with which the xylem could be loaded with and protected by these products remains a challenge. Management of laurel wilt in commercial avocado production areas is discussed.     

Shea (<Emphasis Type="Italic">Vitellaria paradoxa</Emphasis> C. F. Gaertn.) at the crossroads: current knowledge and research gaps

Shea (Vitellaria paradoxa C. F. Gaertn.) is arguably socio-economically and environmentally the most important plant species in the semi-arid and arid zones of Africa where it is widely distributed. Apart from the economic gains in international export markets where shea butter is valued for use in luxury cosmetic, pharmaceutical and confectionary industries, locally the fat (butter) is the main cooking oil for over 86 million inhabitants. Research during the past decades has acknowledged the chemical and nutritional composition as well as the ethnobotanical uses of shea which has resulted in its butter being used in a wide array of products. This review summarizes the current knowledge of the morphological and genetic diversity; propagation, initial growth, and management; ecology and population structure; chemical and nutritional composition as well as the socioeconomic and livelihood empowerment potential of shea. Little is known about the fruiting behaviour and the responses of shea to the inevitable changes in climate. We suggest ecophysiological and dendrochronological studies as an option to predict how the domestication of this multipurpose tree species can be sustained even under the prospects of global climate change.     

Effects of fallow system and cropping frequency upon quantity and composition of earthworm casts

The quantities of earthworm surface casts were monitored in traditional bush fallow regrowth (BFR), Pueraria phaseoloides live mulch (PLM), Leucaena leucocephala alley cropping (LAC) and undisturbed forest. The fallow systems were planted to maize/cassava intercrop either permanently or for one year after three years of fallow i.e. at 100 and 25% cropping frequencies. Earthworm casting activity was lower in fields cropped after clearing three year old fallow than in the respective permanently cropped fallow management system. The reduction in casting was related both to the degree of biomass removed through burning and to re-establishment of cover crops. Higher exchangeable cation concentration in the soil did not cause increased casting activity. Concentrations of organic C, total N and exchangeable Ca and Mg in casts were significantly higher than in the 0–15 cm topsoil. Exchangeable Ca and Mg in casts did not significantly differ between treatments, with the exception of significantly higher Mg in casts after three years of P. phaseoloides fallow. Topsoil (0–15 cm) exchangeable Ca and Mg were not correlated with cast exchangeable Ca and Mg, but concentrations of organic C and total N in casts were significantly correlated with organic C and total N in the topsoil. Coefficients of variability of organic C, total N and exchangeable Ca and Mg were about twice as high in the soil than in casts. Significant negative correlations between the cast to soil ratio (cast enrichment factor) of organic C, total N and exchangeable Ca and Mg and the respective concentrations in the soil show that earthworms are increasingly selective in organic carbon and nutrient uptake as these parameters of soil fertility are declining.     

A qPCR MGB probe based eDNA assay for European freshwater pearl mussel (Margaritifera margaritifera L.)

1. Environmental (e)DNA assays are becoming increasingly used to detect rare or invasive aquatic species. 2. The Critically Endangered freshwater pearl mussel Margaritifera margaritifera is undergoing range‐wide reduction in population numbers and distribution. 3. An eDNA assay to detect the presence of M. margaritifera was developed, based on the mitochondrial cytochrome oxidase I gene, utilizing species‐specific primers, a minor groove binding (MGB) probe and quantitative (q)PCR approaches. 4. The results from this pilot study demonstrated high sensitivity both in laboratory and field trials, and provide a valuable non‐invasive tool for detecting M. margaritifera.