Steryl phenolic acid esters in cereals and their milling fractions

The steryl ferulate contents of rye and wheat grains and their milling fractions were analyzed using a reversed-phase high-performance liquid chromatographic (HPLC) method. HPLC-mass spectrometry was used for identification. In addition, steryl ferulates of some selected milling byproducts were determined. The total steryl ferulate contents of rye and wheat grains were 6.0 and 6.3 mg/100 g, respectively. Uneven distribution of steryl ferulates in the grains led to considerable differences in the milling products; their steryl ferulate contents ranged from trace amounts in flours with low ash content to 20 and 34 mg/100 g in rye and wheat brans, respectively. Campestanyl ferulate and sitostanyl ferulate were the main components, followed by campesteryl ferulate and sitosteryl ferulate, whereas sitosterol was the main component in total sterols. Among the other samples, a byproduct of rice milling (pearling dust) was the best source of steryl ferulates, its total steryl ferulate content being 119 mg/100 g, whereas no measurable amounts of steryl ferulates were measured in oat bran or pearling dust of barley. The results indicated that rye and wheat and especially their bran fractions are comparable to corn as steryl ferulate sources.     

Road and railway verges serve as dispersal corridors for grassland plants

The role of linear habitat strips as dispersal corridors is a disputed topic. Reports concerning their significance for animals have been contradictory, and the functions of corridors have been difficult to study in the case of sedentary organisms such as plants. Previous studies on dispersal of plants along corridors have concentrated on a single or a few species at a time. We developed a general method, a generalisation of the binomial test, for considering dispersal or spatial relations of a large group of species. Particularly, we studied the ability of grassland plants to spread along road and railway verges. Our data set consists of plant lists collected at study plots scattered irregularly along road and railway networks. The dispersal ability was assessed by testing whether the species composition at neighbouring sites – measured along roads and railways – reflects spatial dependence within each species. Our result showed that similar combinations of grassland species occurred at neighbouring sites more often than expected in a spatially independent case. We argue that management of verges and spatial autocorrelation of environmental factors were not responsible for the result and thereby we conclude that grassland plants use road and railway corridors for dispersal. This result is encouraging in regards to preservation of grassland plant populations. Although semi-natural and natural grasslands have become scarce, road and railway embankments may partly compensate for this loss, serving as substitute habitats and dispersal routes.     

Diatom derived polyunsaturated aldehydes do not structure the planktonic microbial community in a mesocosm study

Several marine and freshwater diatoms produce polyunsaturated aldehydes (PUA) in wound-activated processes. These metabolites are also released by intact diatom cells during algal blooms. Due to their activity in laboratory experiments, PUA are considered as potential mediators of diatom-bacteria interactions. Here, we tested the hypothesis that PUA mediate such processes in a close-to-field mesocosm experiment. Natural plankton communities enriched with Skeletonema marinoi strains that differ in their PUA production, a plankton control, and a plankton control supplemented with PUA at natural and elevated concentrations were observed. We monitored bacterial and viral abundance as well as bacterial community composition and did not observe any influence of PUA on these parameters even at elevated concentrations. We rather detected an alternation of the bacterial diversity over time and differences between the two S. marinoi strains, indicating unique dynamic bacterial communities in these algal blooms. These results suggest that factors other than PUA are of significance for interactions between diatoms and bacteria.     

Ecotoxicity of Alternative De-icers

Background  De-icers are essential to wintertime road maintenance in Nordic countries. The use of road salts (NaCl, CaCl₂ and MgCl₂) is having significant effects on groundwater. There has been a growing concern of environmental effects resulting from de-icing. Regulatory bodies have tried to find de-icers which have less harmful impacts on soil and groundwater. Alternative new organic de-icers are e.g. potassium formiate, potassium acetate, and calcium magnesium acetate. Objectives  At present, the decision finding for soil and water quality assessment is mainly based on the results of chemical analyses. However, ecotoxicological characterization will provide more useful information for determining environmental effects of de-icers. Methods  Six different de-icers, NaCl, CaCl₂, MgCl₂, potassium formicate KFo, potassium acetate KAc and calcium magnesium acetate CMA were studied with different bioassays. These bioassays were two plant tests (onion Allium cepa root elongation test and duckweed Lemna growth inhibition test), an enzyme inhibition test (reverse electron transport test, RET) and a microbial test (luminescent bacteria Vibrio fischeri, BioTox test). Results and Discussion  Most of the responses of the de-icers tested were toxic to test organisms. CMA was unsuitable for RET and BioTox tests because it was not possible to analyze turbid samples with these bioassays. On the whole, organic chemicals were more toxic than the inorganic salts. According to the Lemna and Allium cepa tests KFo was the most toxic and the toxicity ranking of the de-icers was KFo > KAc > CMA > CaCl₂ > NaCl > MgCl_2. The sensitivity ranking for tests in decreasing order was Lemna > Allium cepa > RET > BioTox. The plant tests proved to be relevant, easy, cost-effective and sensitive screening methods of de-icers: Lemna test was 92 times more sensitive and Allium test 70 times more sensitive than BioTox to KFo. Conclusion and Outlook  The tested de-icers had significant effects on plant growth, microbial luminescence and enzymatic activity. Toxicity could hardly be predicted from the chemical concentrations of these de-icers. In summary, these results demonstrate a need for including toxicity measurements in the evaluation of technologies used in soil treatment and illustrate the potential value of such measurements for ensuring that no or minimal environmental contamination would arise from de-icing process.