Tropane alkaloids in food

A large number of wild and cultured plants produce secondary metabolites that are toxic to humans and animals. Through accidental or intentional mixing of these plants with normal food and feed the consumers of these products will be exposed to the toxins. In this report tropane alkaloids will be discussed

Bacteriological studies on dairy waste activated sludge

Dairy-waste activated sludge was examined for bacterial composition and response to different conditions. Strains isolated were classified mainly into three groups: predominantly coryneform bacteria (largely Arthrobacter), some Achromobacteraceae and a small groups of Pseudomonadaceae. Experiments with representative strains of the three groups confirmed the ultimate predominant position of Arthrobacter.Two thirds of the bacteria gave a neutral reaction on Hugh and Leifson media, and more than half were not proteolytic. The activated sludge showed a ready accumulation of polysaccharides under certain nutritional conditions.Dissimilation of the carbohydrate of the substrate started immediately after adding substrate to an aerated activated sludge suspension. This was demonstrated by a drop in pH, through accumulation of acid intermediates, and a sharp decrease of dissolved O 2 . Dissolved O 2 was estimated by a stirrer-cleaned oxygen electrode. When dissolved O 2 was still available, acetic acid accumulated; when O 2 was exhausted, lactic acid formed.Dissimilation of the proteins usually started after the carbohydrate was exhausted and lasted longer. This meant that there may be an important discrepancy between the original and the actual C/N relation of the substrate.Experiments with Sphaerotilus natans and Arthrobacter strains, and published data yielded an explanation of the mechanism of bulking of activated sludge

Mutants as an aid to the study of higher plant photomorphogenesis

Study of photomorphogenesis is often complicated by the interaction of different photoreceptors regulating a given process or by the induction of multiple effects by a single photoreceptor. Mutants in which particular components of the morphogenetic pathways are eliminated provide the possibility of studying a more simplified form of photomorphogenesis. Three classes of photomorphogenetic mutants are proposed: photoreceptor, transduction chain and response mutants. In this study three mutants have been used: two have an elongated hypocotyl when grown in white light (the aurea ( au ) tomato mutant and the long hypocotyl ( lh ) cucumber mutant) and one with an enhanced pigment synthesis (the high pigment ( hp ) tomato mutant). The au mutant appears to be a photoreceptor mutant, lacking spectrophotometrically and immunochemically detectable labile phytochrome (lP). The lh mutant is proposed to lack stable phytochrome ( s P) or its function. These mutants enabled the role of s P, l P. and blue light (BL)/UV- photoreceptor(s) in several photophysiological processes to be studied. The results of these experiments indicate that l P plays a role in both hypocotyl elongation and anthocyanin synthesis in etiolated seedlings. This provides direct evidence that the 'bulk' l P is functional. In etiolated seedlings the au tomato mutant with its deficiency in l P is 'red-blind' and has a shift of fluence rate response curves for hypocotyl inhibition by BL and UV-A approximately l order of magnitude to higher fluence rates. In light-grown plants it is proposed that s P regulates the end-of-day far-red light (FR) response and the inhibition of hypocotyl elongation due to light perception by the cotyledons. Furthermore, these mutants with reduced phytochrome (P) content provide direct experimental evidence that the FR absorbing form of P (Pfr) is the active form indeed. If removal of the red light (RL) absorbing form of P (Pr) is the active photomorphogenetic process, instead of an increase of Pfr, seedlings with a reduced P content would be expected to be short. However, dark-grown seedlings of lh mutant and au mutant are both elongated. The hp mutant with its enhanced anthocyanin synthesis has enabled induction of anthocyanin synthesis in tomato seedlings in response to a single RL pulse to be observed, whereas in wild type this synthesis it too low to be measured. Study of anthocyanin synthesis with the aid of the hp mutant, the au mutant and the au/hp double mutant supports the conclusion that P is the terminal photoreceptor involved in tomato and that BL (operating through the BL/UV-photoreceptor or P) sensitizes the seedling to P action at a later stage. Using a computer-controlled apparatus for continuous growth measurement, designed and constructed for this study, it has been possible to show the differences in kinetics of hypocotyl inhibition by BL or RL in both the lh mutant and its wild type. In BL inhibition started almost immediately after the onset of irradiation, whereas in RL a lag period of several hours was observed

Trendanalyse dierlijke eiwitten in diervoeder(grondstoffen)

In dit rapport worden, in opdracht van de VWA, historische gegevens gebruikt om inzicht te krijgen in het voorkomen van dierlijke eiwitten (bestanddelen) in diervoeders en diervoedergrondstoffen. Dierlijke eiwitten in diervoeders spelen een belangrijke rol in het verspreiden van BSE (gekke koeien ziekte). Daarom zijn er maatregelen genomen om blootstelling van runderen aan dierlijk eiwit via het diervoeder te voorkomen. Er zijn diverse verboden en regels door de Europese overheid opgelegd en door de Nederlandse overheid (VWA) wordt toezicht gehouden op de naleving van deze regelgevin

Trendanalyse zware metalen in diervoeder(grondstoffen)

In dit rapport wordt er met behulp van historische waarden inzicht gegeven in het verloop van de gehalten aan kwik, cadmium en lood in diervoeders en diervoedergrondstoffen in Nederland. Het is een vervolg op het rapport 2007.001 “Trendanalyse van gehalten aan aflatoxine B1 en dioxinen/dioxine-achtige PCB’s in diervoeders” dat in 2007 is verschenen. Dit onderzoek is ook verricht op verzoek van de VWA. De resultaten van deze analyses bieden mogelijkheden voor de VWA om tot een meer risico-gestuurde bemonstering in het Nationaal Plan Diervoeders te kome

Trend analysis of mycotoxins in animal feed

Feed materials were analysed for the mycotoxins deoxynivalenol, ochratoxin A, zearalenone, aflatoxin B1, fumonisin B1 and B2, and HT-2- and T-2-toxins. In this report trends in the average content during the period 2001-2009 are reported for these mycotoxins. Monitoring data from the National Feed monitoring program and from the Commodity Board Animal Feed are used for this study