Qualitative and quantitative evaluation of glucosinolates in cruciferous plants during their life cycles

Glucosinolates produced by Brassica species were investigated in relation to biofumigation, a term used to describe the effects some allelochemicals, including glucosinolate derived products, may have on soil-borne pathogens or other herbivores. Four Brassica species of the U-triangle, namely B. nigra (L.) Koch, B. carinata Braun, B. juncea (L.) Czern. and B. rapa L. were compared with respect to their qualitative and quantitative glucosinolate profiles in roots, stems, leaves and reproductive organs. Plants were monitored at four different development stages and the total glucosinolate content as well as their dry matter production as an indication of their potential biomass under field conditions were determined. Glucosinolate levels of up to 120 ìmol g -1 DM were found in B. nigra and B. juncea, while B. rapa did not show values over 25 ìmol g-1 DM at any stage of the investigated plant life cycles. In the three species at the top of U-triangle, reproductive tissues showed the highest glucosinolate concentration when compared to the rest of the plant parts, while in B. rapa, the roots were the organs with the highest glucosinolate concentration. The glucosinolate profile of the different plant parts of the species studied changed during the growth cycle, showing that the trade-off between glucosinolate profile and biomass production should be optimized in order to maximize the biofumigation effect of a crop. However, further information on other allelochemicals and on the different types of glucosinolate derived products resulting from autolysis or myrosinase catalyzed hydrolysis of glucosinolates at different reaction conditions is needed for the appropriate description of the potential biofumigation effects of different crops

Influence of pH and type of myrosinase complex on the products obtained in the myrosinase catalysed hydrolysis of glucosinolates – a MECC study

Environmental conditions, e.g. pH and the presence of Fe2+ are well known factors that influence the product profile of the myrosinase catalysed hydrolysis of glucosinolates. Depending on the plant genera, the species and tissue of origin myrosinase isoenzymes (thioglucohydrolase EC 3.2.1.147) have different characteristics in terms of MW, subunit composition and pI. However, the influence of these parameters on the outcome of glucosinolate hydrolysis has not been traditionally studied, which hinders the full exploitation of the catalytic potential of these enzymes. In the present experiments the effect of myrosinase type on the products obtained in the hydrolysis of glucosibarin was studied by MECC using two B. carinata myrosinase preparations differing on their affinity to the Con A material, Con A 1 (first eluting fractions) and Con A 2 (last eluting fractions). At pH 3 Con A 1 isoenzymes were more active than Con A 2 isoenzymes. At pH 5 and 6.5 Con A 1 isoenzymes produced oxazolidine-2-thione to a higher extent than Con A 2 isoenzymes. The production of nitriles by Con A 1 isoenzymes was not influenced by pH and at pH 5 and 6.5 the amount of nitrile produced by Con A 1 isoenzymes was lower than that produced by Con A 2 isoenzymes. Formation of nitriles requires the presence of two redox equivalents which leads to the release of the sulphur atom from the aglucone. Isothiocyanates and nitriles differ in their bioactivity towards different targets; therefore the possibility for directing the glucosinolate hydrolysis towards the desired compound in a particular situation is of great relevance

Nutritional value of cruciferous oilseed crops in relation to profile of accumulated biomolecules with especial regard to glucosinolates transformation products

Cruciferous oilseed crops accumulate relatively high concentrations of nutritional high quality oil and proteins in their seeds. In addition to these major seed components, their co-occurrence with high concentrations of dietary fibre (DF) and various bioactive components as glucosinolates/glucosinolate products is decisive for the nutritional value of the seed meal or products obtained from it. Depending on structural types and concentration of glucosinolates and glucosinolate derived products, these compounds can be either health beneficial or act as antinutrients. The effects of these components depend, however, strongly on the type of animal and development of the animals fed with the diets based on these compounds. Results from studies based on differently treated and processed seeds and from use of individual isolated seed components included in standard diets are evaluated and treated in relation to literature data as a basis for recommendations of acceptable concentrations of glucosinolates/glucosinolate products in animal diets. A discussion on the relation between these recommendations of acceptable concentrations in feed to different animals and those reported as necessary for plant pathogen control (biofumigation) and health beneficial effects (chemoprotection) is also included

Processing-bioprocessing of oilseed rape in bioenergy production and value added utilization of remaining seed components

Cruciferous oilseed crops accumulate relatively high concentrations of oil, proteins and dietary fibres (DF) in their seeds, in addition to bioactive components as glucosinolates and myrosinase isoenzymes (thioglucohydrolase; EC 3.2.1.147). When mixed in the presence of moisture, myrosinase isoenzymes and associated components transform glucosinolates into various types of products, which reduces the value of the extracted oil and the remaining seed components, as well as producing unwanted environmental effects due to smell and toxicity. This gives a need for special care concerning myrosinase inactivation as the initial step during processing of oilseed rape, including technologies applied for biodiesel/bioenergy production. The myrosinase inactivation is thus a critical processing step, which needs to be performed at conditions with limited negative effects on other seed components, including proteins and glucosinolates. New bioprocessing technologies are now developed at levels that allow technology transfer from laboratory scale through pilot plant to industrial scale. The extraction of glucosinolates from the seed components remaining after oil separation-pressing and/or extraction is technically possible and has proven successful with the use of bioprocessing technologies. This is also the case concerning isolation of active myrosinases. The possibilities therefore exist for extraction and formulation of glucosinolates as “natural product derived” food and plant protection agents. With the great amounts of partly de-oiled rapeseed meal resulting from bioenergy/biodiesel production, the new bioprocessing technologies call thus for attention in relation to environmental friendly production of food (vegetable oil, protein and DF products), feed and other non food products

ICROFS news 1/2012. Newsletter from ICROFS

International organic research theme: Organic Farming in Brazil: Organic milk production in Brazil Mokichi Okada Research Center - Agricultural research and development Effect of alternative fertilization: Productive and qualitative per-formance in recovering degraded pastures in Brazil CORE Organic: Preventing disease and parasites in european organic pi

Glucosinolate hydrolysis compounds for weed control

Glucosinolates are allelochemicals present in all Brassica plants. Upon hydrolysis by endogenous enzymes they produce a series of biologically active compounds, such as isothiocyanates and their deriva-tives among others. These compounds have marked fungicidal, nematocidal and herbicidal effects and therefore their use as biodegradable natural products for crop protection has attracted much attention in the last years. A number of these compounds, either individually or in combination, were tested against Sinapis alba and Lollium perenne in Petri dishes bio-assays. C50 values as low as 0.7 and 0.2 mM were obtained. This may open the possibility for using glucosinolate hydrolysis products as herbicides

A Note on Shortest Developments

De Vrijer has presented a proof of the finite developments theorem which, in addition to showing that all developments are finite, gives an effective reduction strategy computing longest developments as well as a simple formula computing their length. We show that by applying a rather simple and intuitive principle of duality to de Vrijer's approach one arrives at a proof that some developments are finite which in addition yields an effective reduction strategy computing shortest developments as well as a simple formula computing their length. The duality fails for general beta-reduction. Our results simplify previous work by Khasidashvili

Salmonella Infection Level in Danish Indoor and Outdoor Pig Production Systems measured by Antbodies in Meat Juice and Faecal Shedding on-farm and at Slaughter

The prevalence of Salmonella shedding was compared in 34 organic, conventional outdoor, and indoor pig herds. Individual faecal and meat juice samples from 30-50 pigs per herd were analysed for presence of Salmonella, and Salmonella antibodies, respectively. We found low levels of Salmonella shedding on farm and at slaughter in organic and conventional outdoor herds compared to indoor pigs. Overall 5,5 % of the pigs were seropositive. The serological test result was associated with Salmonella shedding at slaughter in pigs from conventional systems, but not in organic pigs. The duration of transport did not affect the risk of Salmonella shedding