NobleBlocks
Ministry of Agriculture, Nature and Food Quality logo

Ministry of Agriculture, Nature and Food Quality

governmentThe Hague, Netherlands

Research output, citation impact, and the most-cited recent papers from Ministry of Agriculture, Nature and Food Quality (Netherlands). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
549
Citations
32.5K
h-index
82
i10-index
442
Also known as
Ministerie van Landbouw, Natuur en VoedselkwaliteitMinistry of Agriculture, Nature and Food Quality

Top-cited papers from Ministry of Agriculture, Nature and Food Quality

Intake of potentially anticarcinogenic flavonoids and their determinants in adults in the Netherlands
Michaël G. L. Hertog, P.C.H. Hollman, Mira Katan, Daan Kromhout
1993· Nutrition and Cancer1.2Kdoi:10.1080/01635589309514267

Flavonoids are strong antioxidants that occur naturally in foods and can inhibit carcinogenesis in rodents. Accurate data on population-wide intakes of flavonoids are not available. Here, using data of the Dutch National Food Consumption Survey 1987-1988, we report the intake of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin among 4,112 adults. The flavonoid content of vegetables, fruits, and beverages was determined by high-performance liquid chromatography. In all subjects, average intake of all flavonoids combined was 23 mg/day. The most important flavonoid was the flavonol quercetin (mean intake 16 mg/day). The most important sources of flavonoids were tea (48% of total intake), onions (29%), and apples (7%). Flavonoid intake did not vary between seasons; it was not correlated with total energy intake (r = 0.001), and it was only weakly correlated with the intake of vitamin A (retinol equivalents, r = 0.14), dietary fiber (r = 0.21), and vitamin C (r = 0.26). Our use of new analytic technology suggests that in the past flavonoid intake has been overestimated fivefold. However, on a milligram-per-day basis, the intake of the antioxidant flavonoids still exceeded that of the antioxidants beta-carotene and vitamin E. Thus flavonoids represent an important source of antioxidants in the human diet.

SARS-CoV-2 infection in farmed minks, the Netherlands, April and May 2020
Nadia Oreshkova, Robert Jan Molenaar, Sandra Vreman, Frank Harders +4 more
2020· Eurosurveillance772doi:10.2807/1560-7917.es.2020.25.23.2001005

Respiratory disease and increased mortality occurred in minks on two farms in the Netherlands, with interstitial pneumonia and SARS-CoV-2 RNA in organ and swab samples. On both farms, at least one worker had coronavirus disease-associated symptoms before the outbreak. Variations in mink-derived viral genomes showed between-mink transmission and no infection link between the farms. Inhalable dust contained viral RNA, indicating possible exposure of workers. One worker is assumed to have attracted the virus from mink.

Relative bioavailability of the antioxidant flavonoid quercetin from various foods in man
P.C.H. Hollman, J.M.P. van Trijp, Michel N. C. P. Buysman, M.S. van der Gaag +3 more
1997· FEBS Letters769doi:10.1016/s0014-5793(97)01367-7

Quercetin is a strong antioxidant and a major dietary flavonoid. Epidemiological studies suggest that consumption of quercetin protects against cardiovascular disease, but its absorption in man is controversial. We fed nine subjects a single large dose of onions, which contain glucose conjugates of quercetin, apples, which contain both glucose and non-glucose quercetin glycosides, or pure quercetin-3-rutinoside, the major quercetin glycoside in tea. Plasma levels were then measured over 36 h. Bioavailability of quercetin from apples and of pure quercetin rutinoside was both 30% relative to onions. Peak levels were achieved less than 0.7 h after ingestion of onions, 2.5 h after apples and 9 h after the rutinoside. Half-lives of elimination were 28 h for onions and 23 h for apples. We conclude that conjugation with glucose enhances absorption from the small gut. Because of the long half-lives of elimination, repeated consumption of quercetin-containing foods will cause accumulation of quercetin in blood.

The sugar moiety is a major determinant of the absorption of dietary flavonoid glycosides in man
P.C.H. Hollman, Michel N.C.P. Bijsman, Yvonne van Gameren, Else P.J. Cnossen +2 more
1999· Free Radical Research546doi:10.1080/10715769900301141

Flavonoids are antioxidants present in plant foods. They occur mainly as glycosides, i.e. linked with various sugars. It is uncertain to what extent dietary flavonoid glycosides are absorbed from the gut. We investigated how the nature of the sugar group affected absorption of one major flavonoid, quercetin. Quercetin linked with glucose, i.e. quercetin glucoside and quercetin linked with rutinose, i.e. quercetin rutinoside, both occur widely in foods. When we fed these compounds to nine volunteers, the peak concentration of quercetin (Cmax) in plasma was 20 times higher and was reached (Tmax) more than ten times faster after intake of the glucoside (Cmax = 3.5+/-0.6 microM (mean +/- SE); Tmax < 0.5 h) than after the rutinoside (Cmax = 0.18+/-0.04 microM; Tmax = 6.0+/-1.2 h). The bioavailability of the rutinoside was only 20% of that of the glucoside. We suggest that quercetin glucoside is actively absorbed from the small intestine, whereas quercetin rutinoside is absorbed from the colon after deglycosylation. Absorption of other food components might also be enhanced by attachment of a glucose group.

Flavonols, flavones and flavanols - nature, occurrence and dietary burden
P.C.H. Hollman, Ilja C.W. Arts
2000· Journal of the Science of Food and Agriculture518doi:10.1002/(sici)1097-0010(20000515)80:7<1081::aid-jsfa566>3.0.co;2-g

Total flavonol and flavone contents of foods have been determined with validated state-of-the-art methods. Quercetin dominates, and flavonol levels found in vegetables and fruits are below 10 mg kg−1. However, high concentrations are found in onions (300 mg kg−1), kale (450 mg kg−1), broccoli (100 mg kg−1), beans (50 mg kg−1), apples (50 mg kg−1), blackcurrants (40 mg kg−1), and tea (30 mg l−1). The dietary intake of flavonols varies 10-fold between countries (6–60 mg day−1). Flavones are of minor importance in the diet. Tea, wine and fruits are the most important sources of flavanols, but there are gaps in our knowledge on flavanol levels of many foods. The absorption of dietary quercetin glycosides in humans ranges from 20 to 50%. The sugar moiety is an important determinant of the bioavailability of flavonols. The presence of a glucose moiety significantly enhances absorption. The extent of absorption of flavanols in humans seems similar to that of flavonols but has been little studied. Flavonols and flavanols are extensively metabolised, as only 1–2% of them are excreted with an intact flavonoid backbone. Hepatic biotransformations include glucuronidation and sulphatation of the phenolic hydroxyls and O-methylation of catechol groups. Bacteria of the colon cleave the C-ring of the flavonoid nucleus to phenolic acids which are subsequently absorbed. Apart from conjugates, virtually no metabolites have been characterised in humans. Absorption of flavanols is rather fast, with times to reach peak values between 0.5 and 4 h. Flavanols are rapidly excreted, with elimination half-lives of 1–6 h. Quercetin glycosides show rapid to slow absorption; peak values are reached between < 0.5 and 9 h. The type of glycoside determines the rate of absorption. Excretion of quercetin glycosides is slow: elimination half-lives are 24 h, independent of the type of glycoside. Analytical data for flavanols in foods are needed. Tea, as an important dietary source, has to be studied. Research on the bioavailability of flavonols and flavanols has to be expanded. Attention is needed for the identification and quantification of their metabolites in body fluids. © 2000 Society of Chemical Industry

Role of Ethylene in Senescence of Petals—Morphological and Taxonomical Relationships
Ernst J. Woltering, Wouter G. van Doorn
1988· Journal of Experimental Botany455doi:10.1093/jxb/39.11.1605

Petal senescence in mature flowers was studied in 93 species from 22 families. The initial symptom of senescence was either wilting or abscission, but in some species the time span between wilting and abscission was very short. There was no apparent relationship between corolla form (choripetalous or sympetalous), ovary position (inferior or superior with respect to the corolla) and type of senescence (initial wilting or initial abscission). In monocots no initial abscission was found, while in dicots the difference between the wilting type and the abscission type was generally at the family level. With respect to petal senescence, sensitivity to exogenous ethylene (C2H4) was also related to the family level. Except for a few families (all tested Campanulaceae, Caryophyllaceae and Malvaceae, and most Orchidaceae), most of the flowers investigated that showed initial wilting were not sensitive to exogenous ethylene, e.g. all tested Compositae, Iridaceae, and Liliaceae. Most of the flowers showing initial abscission were sensitive to exogenous ethylene (Geraniaceae, Labiatae, Ranunculaceae, Rosaceae, Scrophulariaceae). Experiments with silver thiosulphate (STS) confirmed the effects of exogenous ethylene, both in flowers showing initial wilting and in flowers showing initial abscission. The data indicate, therefore, that ethylene is involved in the natural senescence of only a minority of the wilting type of flowers and in a majority (if not all) of the abscising type of flowers.

Evidence for health benefits of plant phenols: local or systemic effects?
P.C.H. Hollman
2001· Journal of the Science of Food and Agriculture381doi:10.1002/jsfa.900

Abstract Plant phenols are mostly products of the phenylpropanoid pathway and comprise a large variety of compounds: cinnamic acids, benzoic acids, flavonoids, proanthocyanidins, stilbenes, coumarins, lignans and lignins. They are strong antioxidants and might prevent oxidative damage to biomolecules such as DNA, lipids and proteins which play a role in chronic diseases such as cancer and cardiovascular disease. Plant phenols may interfere with all stages of the cancer process, potentially resulting in a reduction of cancer risk. Only flavonols have been investigated in observational studies. Five out of seven studies showed an inverse association of flavonol intake with subsequent cardiovascular disease (CVD). A protective effect against cancer was only found in one out of four studies. Thus the epidemiological evidence does not yet allow a firm decision on the involvement of flavonols in the aetiology of either CVD or cancer. The epidemiology of flavonols points to a systemic effect. The epidemiology of tea, as a rich source of various phenols, shows inconsistent data for colon cancer, which also does not support a local effect of plant phenols. The absorption and bioavailability of plant phenols have been inadequately studied. Dietary flavonoids were thought to be poorly absorbed because of their presence as β‐glycosides (conjugates of sugars). However, conjugation with glucose enhanced human absorption. Flavonoids and other plant phenols are extensively metabolised by colonic bacteria: the ring structure is cleaved, giving a range of phenolic acids which are then absorbed. Human studies showed that only about 1% of a well‐absorbed flavonoid was excreted with an intact flavonoid backbone into urine. Major questions to be answered are whether the effective concentrations found in in vitro systems really reflect physiological concentrations. © 2001 Society of Chemical Industry

Developing multiscale and integrative nature–people scenarios using the Nature Futures Framework
Laura Pereira, Kathryn K. Davies, E. den Belder, Simon Ferrier +4 more
2020· People and Nature324doi:10.1002/pan3.10146

Abstract Scientists have repeatedly argued that transformative, multiscale global scenarios are needed as tools in the quest to halt the decline of biodiversity and achieve sustainability goals. As a first step towards achieving this, the researchers who participated in the scenarios and models expert group of the Intergovernmental Science‐Policy Platform on Biodiversity and Ecosystem Services (IPBES) entered into an iterative, participatory process that led to the development of the Nature Futures Framework (NFF). The NFF is a heuristic tool that captures diverse, positive relationships of humans with nature in the form of a triangle. It can be used both as a boundary object for continuously opening up more plural perspectives in the creation of desirable nature scenarios and as an actionable framework for developing consistent nature scenarios across multiple scales. Here we describe the methods employed to develop the NFF and how it fits into a longer term process to create transformative, multiscale scenarios for nature. We argue that the contribution of the NFF is twofold: (a) its ability to hold a plurality of perspectives on what is desirable , which enables the development of joint goals and visions and recognizes the possible convergence and synergies of measures to achieve these visions and (b), its multiscale functionality for elaborating scenarios and models that can inform decision‐making at relevant levels, making it applicable across specific places and perspectives on nature. If humanity is to achieve its goal of a more sustainable and prosperous future rooted in a flourishing nature, it is critical to open up a space for more plural perspectives of human–nature relationships. As the global community sets out to develop new goals for biodiversity, the NFF can be used as a navigation tool helping to make diverse, desirable futures possible. A free Plain Language Summary can be found within the Supporting Information of this article.

Avian Influenza A Virus (H7N7) Epidemic in The Netherlands in 2003: Course of the Epidemic and Effectiveness of Control Measures
Arjan Stegeman, A. Bouma, A.R.W. Elbers, M.C.M. de Jong +4 more
2004· The Journal of Infectious Diseases304doi:10.1086/425583

An epidemic of high-pathogenicity avian influenza (HPAI) A virus subtype H7N7 occurred in The Netherlands in 2003 that affected 255 flocks and led to the culling of 30 million birds. To evaluate the effectiveness of the control measures, we quantified between-flock transmission characteristics of the virus in 2 affected areas, using the reproduction ratio Rh. The control measures markedly reduced the transmission of HPAI virus: Rh before detection of the outbreak in the first infected flock was 6.5 (95% confidence interval [CI], 3.1-9.9) in one area and 3.1 in another area, and it decreased to 1.2 (95% CI, 0.6-1.9) after detection of the first outbreak in both areas. The observation that Rh remained >1 suggests that the containment of the epidemic was probably due to the reduction in the number of susceptible flocks by complete depopulation of the infected areas rather than to the reduction of the transmission by the other control measures.

Shifting Mosaics in Grazed Woodlands Driven by the Alternation of Plant Facilitation and Competition
Han Olff, F. W. M. Vera, J. Bokdam, Elisabeth S. Bakker +3 more
1999· Plant Biology256doi:10.1111/j.1438-8677.1999.tb00236.x

Abstract: Free‐ranging large grazers, such as cattle and horses, are increasingly reintroduced to former agricultural areas in Western Europe in order to restore natural and diverse habitats. In this review we outline mechanisms by which large grazers induce and maintain structural diversity in the vegetation (mosaics of grasslands, shrub thickets and trees). This variation in vegetation structure is considered to be important for the conservation of biodiversity of various plant and animal groups. The process of spatial association with unpalatable plants (as‐sociational resistance) enables palatable plants to establish in grasslands maintained by large grazers. In this way, short unattractive (thorny, low quality or toxic) species facilitate taller unattractive shrubs, which facilitate palatable trees, which in turn outshade the species that facilitated their recruitment. Established trees can, therefore, not regenerate under their own canopy, leading to cyclic patch dynamics. Since this cyclic dynamic occurs on a local scale, this contributes to shifting mosaics. The mechanisms involved in creating and maintaining the resulting shifting mosaics are described for temperate flood‐plain and heathland ecosystems, including the effects on nutrient transport within grazed landscapes. How grazing leads to shifting mosaics is described in terms of plant functional types, allowing potential generalisation to other ecosystems. The resulting interaction web of grasses, unpalatable forbs and shrubs, palatable light‐demanding trees and shade‐tolerant trees is discussed, and was found to contain various interesting direct and indirect effects. The key process contributing to spatial diversity in vegetation structure is the alternation of positive (facilitation) interactions between plant species at one life cycle stage, and competitive displacement at another stage. Grazing thus causes directional successional sequences to change to shifting mosaics. The implications of this theory for nature conservation are discussed, including the relevant management problems, possible choices and practical solutions. We conclude that the theoretical framework outlined in this review provides helpful insights when coping with nature conservation issues in temperate woodland habitats.

Role of dietary flavonoids in protection against cancer and coronary heart disease
P.C.H. Hollman, M.G.L. Hertog, Mira Katan
1996· Biochemical Society Transactions198doi:10.1042/bst0240785

Conference Article| August 01 1996 Role of dietary flavonoids in protection against cancer and coronary heart disease P. C. H. Hollman; P. C. H. Hollman § *DLO State Institute for Quality Control of Agricultural products (RIKILT-DLO), Bornsesteeg 45, NL-6708 PD Wageningen, The Netherlands §To whom correspondence should be addressed. Search for other works by this author on: This Site PubMed Google Scholar M. G. L. Hertog; M. G. L. Hertog †National Institute of Public Health and Environmental Protection, P.O. Box I, NL-3720 BA Bilthoven, The Netherlands Search for other works by this author on: This Site PubMed Google Scholar M. B. Katan M. B. Katan ‡Agricultural University, Department of Human Nutrition, Bomenweg 2, NL-6703 HD Wageningen, The Netherlands Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1996) 24 (3): 785–789. https://doi.org/10.1042/bst0240785 Article history Received: March 20 1996 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation P. C. H. Hollman, M. G. L. Hertog, M. B. Katan; Role of dietary flavonoids in protection against cancer and coronary heart disease. Biochem Soc Trans 1 August 1996; 24 (3): 785–789. doi: https://doi.org/10.1042/bst0240785 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search Keywords: LDL, low-density lipoprotein This content is only available as a PDF. © 1996 Biochemical Society1996 Article PDF first page preview Close Modal You do not currently have access to this content.

Evidence for transplacental and contact transmission of bluetongue virus in cattle
F. D. Menzies, Sam McCullough, I. M. McKeown, Julie L. Forster +4 more
2008· Veterinary Record164doi:10.1136/vr.163.7.203

This paper presents evidence that a field strain of bluetongue virus serotype 8 (BTV-8) was transmitted transplacentally and that it was also spread by a direct contact route. Twenty pregnant heifers were imported from the Netherlands into Northern Ireland during the midge-free season. Tests before and after the animals were imported showed that eight of them had antibodies to bluetongue virus, but no viral RNA was detected in any of them by reverse transcriptase-PCR (RT-PCR). Two of the seropositive heifers gave birth to three calves that showed evidence of bluetongue virus infection (RT-PCR-positive), and one of the calves was viraemic. Two further viraemic animals (one newly calved Dutch heifer, and one milking cow originally from Scotland) were also found to have been infected with BTV-8 and evidence is presented that these two animals may have been infected by direct contact, possibly through the ingestion of placentas infected with BTV-8.

Addition of milk does not affect the absorption of flavonols from tea in man
P.C.H. Hollman, Karin H. van het Hof, Lilian B.M. Tijburg, Mira Katan
2001· Free Radical Research144doi:10.1080/10715760100300261

Tea is a major source of flavonols, a subclass of antioxidant flavonoids present in plant foods which potentially are beneficial to human health. Milk added to tea, a frequent habit in the United Kingdom, could inhibit absorption of tea flavonoids, because proteins can bind flavonoids effectively. Eighteen healthy volunteers each consumed two out of four supplements during three days: black tea, black tea with milk, green tea and water. A cup of the supplement was consumed every 2 hours each day for a total of 8 cups a day. The supplements provided about 100 micromol quercetin glycosides and about 60 - 70 micromol kaempferol glycosides. Addition of milk to black tea (15 ml milk to 135 ml tea) did not change the area under the curve of the plasma concentration-time curve of quercetin or kaempferol. Plasma concentrations reached were about 50 nM quercetin and 30 - 45 nM kaempferol. We conclude that flavonols are absorbed from tea and that their bioavailability is not affected by addition of milk.

Influence of physical stress on the plasma concentration of serum amyloid‐a (SAA) and haptoglobin (HP) in calves
S.P.M. Alsemgeest, I. Lambooy, H.K. Wierenga, S.J. Dieleman +3 more
1995· Veterinary Quarterly138doi:10.1080/01652176.1995.9694521

The influence of physical stress on the plasma concentration of the acute-phase proteins serum amyloid-A (SAA) and haptoglobin (Hp) was studied in 10 calves. Two different stress levels were created by housing two groups of five calves, each on different types of floor. The stress level was assessed by studying videotapes of the animals, and, subsequently, by quantifying the problems related with moving across the pens and the time the calves spent lying down and standing. Plasma concentrations of Hp, SAA, aldolase, and cortisol were measured in blood samples obtained by jugular venepuncture. Plasma SAA concentrations were significantly (p < 0.001) elevated in animals housed on the floor type associated with the highest level of physical stress, although the concentrations were within the normal range for healthy adult cattle. Hp concentrations were not elevated. The floor type did not alter the stress related biochemical variables aldolase and cortisol. It is concluded that plasma SAA concentrations rise upon physical stress, whereas Hp concentrations do not change. The absence of a significant difference in aldolase or cortisol concentrations indicates that the difference in the level of neuro-endocrine stress between the animals housed on the two floor types is only minimal. Consequently, SAA is suggested to be a sensitive variable to assess physical welfare in calves.

Effect of Climate Conditions and Plant Developmental Stage on the Stability of Antibodies Expressed in Transgenic Tobacco
L.H. Stevens, Geert Stoopen, I.J.W. Elbers, Jos Molthoff +4 more
2000· PLANT PHYSIOLOGY132doi:10.1104/pp.124.1.173

Plants are regarded as a promising system for the production of heterologous proteins. However, little is known about the influence of plant physiology and plant development on the yield and quality of the heterologous proteins produced in plants. To investigate this, tobacco (Nicotiana tabacum cv Samsun NN) was transformed with a single construct that contained behind constitutive promotors the light- and heavy-chain genes of a mouse antibody. The in planta stability of the antibody was analyzed in transgenic plants that were grown under high and low irradiation at 15 degrees C and 25 degrees C. High-light conditions favored the production of biomass, of total soluble protein, and of antibody. The plants grown at 25 degrees C developed faster and contained less antibody per amount of leaf tissue than the plants grown at 15 degrees C. Both endogenous protein and antibody content showed a strong decline during leaf development. The heavy chains of the antibody underwent in planta degradation via relatively stable fragments. In vitro incubations of purified plantibody with leaf extracts of wild-type tobacco indicated the involvement of acidic proteases. It is interesting that the same antibody produced by mouse hybridoma cells exhibited higher stability in this in vitro assay. This may be explained by the assumption that the plant type of N-glycosylation contributes less to the stability of the antibody than the mouse-type of N-glycosylation. The results of this study indicate that proteolytic degradation during plant development can be an important factor affecting yield and homogeneity of heterologous protein produced by transgenic plants.

Validation and use of the CALUX‐bioassay for the determination of dioxins and PCBs in bovine milk
Toine F. H. Bovee, L.A.P. Hoogenboom, Astrid R. M. Hamers, W.A. Traag +4 more
1998· Food Additives & Contaminants103doi:10.1080/02652039809374723

There is a strong need for the development of relatively cheap and rapid bioassays for the determination of dioxins and related compounds in food. A newly developed CALUX (Chemical-Activated LUciferase gene eXpression) bioassay was tested for its possible use to determine low levels of dioxins in bovine milk. Data show that this mammalian cell-based test is very sensitive for 2,3,7,8-substituted dioxins and related PCBs, thereby reflecting the relative potencies of these compounds in comparison to TCDD (TEF-values). The limit of detection was about 50 fg of TCDD. Furthermore, the response obtained with a mixture of dioxins was additive, in accordance with the TEF-principle. Milk fat was isolated by centrifugation followed by clean-up of the fat with n-pentane, removal of the fat on a 33% H2SO4 silica column, and determination of Ah receptor agonist activity with the CALUX-bioassay. An equivalent of 67 mg fat was tested per experimental unit, resulting in a limit of quantification around 1 pg i-TEQ/g fat. To investigate the performance of the method, butter fat was cleaned and spiked with a mixture of 17 different 2,3,7,8-substituted PCDD and PCDF congeners at 1, 3, 6, 9, 12 and 15 pg TEQ/g fat, as confirmed by GC/MS. In this concentration range, the method showed a recovery of TEQs around 67% (58-87%). The reproducibility, determined in three independent series showed a CV varying between 4% and 54%, with the exception of the sample spiked at 1 pg i-TEQ (CV 97%). The repeatability determined with the sample spiked at 6 pg i-TEQ/g showed a CV of 10%. Testing of 22 bovine milk samples, taken at different sites in The Netherlands, in the CALUX-assay showed combined dioxin and dioxin-like PCB levels equivalent to 1.6 pg TCDD/g fat (range 0.2-4.6). GC/MS analysis of these samples revealed an average level of 1.7 pg i-TEQ/g fat, varying between 0.5 and 4.7 pg i-TEQ/g fat. All five samples showing a GC/MS determined dioxin content of more than 2 pg i-TEQ/g fat gave a response in the CALUX-assay corresponding to more than 2 pg TCDD/g fat. These data clearly show that the CALUX-bioassay is a promising method for the rapid and low cost screening of dioxins in bovine milk.

Influence of Growth Conditions and Developmental Stage on<i>N</i>-Glycan Heterogeneity of Transgenic Immunoglobulin G and Endogenous Proteins in Tobacco Leaves
I.J.W. Elbers, Geert Stoopen, Hans Bakker, L.H. Stevens +4 more
2001· PLANT PHYSIOLOGY103doi:10.1104/pp.126.3.1314

Plants are regarded as a promising system for the production of heterologous proteins. However, little is known about the influence of plant development and growth conditions on N-linked glycosylation. To investigate this, transgenic tobacco (Nicotiana tabacum cv Samsun NN) plants expressing a mouse immunoglobulin G antibody (MGR48) were grown in climate rooms under four different climate conditions, i.e. at 15 degrees C and 25 degrees C and at either low or high light conditions. N-glycans on plantibodies and soluble endogenous proteins were analyzed with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS). Antibodies isolated from young leaves have a relatively high amount of high- mannose glycans compared with antibodies from older leaves, which contain more terminal N-acetylglucosamine. Senescence was shown to affect the glycosylation profile of endogenous proteins. The relative amount of N-glycans without terminal N-acetylglucosamine increased with leaf age. Major differences were observed between glycan structures on endogenous proteins versus those on antibodies, probably to be attributed to their subcellular localization. The relatively high percentage of antibody N-glycan lacking both xylose and fucose is interesting.

Vegetation development in dune slacks: the role of persistent seed banks
R.M. Bekker, E.J. Lammerts, A. de Schutter, Albert Grootjans
1999· Journal of Vegetation Science100doi:10.2307/3237090

Abstract. The soil seed bank composition was determined at four sites in the dune slack ‘Koegelwieck’ on the Dutch Wadden Sea island of Terschelling. At three different sites in the slack, where sod‐cutting experiments down to the mineral sand had been carried out, the established vegetation and seed bank were assessed after 5, 9 and 39 yr of undisturbed development, respectively. In addition, a fourth site in the slack was investigated, where vegetation development had proceeded for 80 yr since plant colonization of bare soil and where nowadays a vegetation dominated by Calamagrostis epigejos and Salix repens occurs. Together these four sites can be regarded as a chronosequence of dune slack formation. Clear time sequences were detected in the seed bank data. Many late successional species showed a significant increase in the number of seeds during the succession. Some of the early successional basiphilous pioneer species such as Anagallis minima, Centaurium littorale, Littorella uniflora, Radiola linoides and Samolus valerandi , showed either a decrease during the time of succession or an optimum in the vegetation while remaining present in the seed bank in low but detectable numbers. They could, therefore, play a role in re‐establishment of the vegetation after sod‐cutting. One of the target species, Schoenus nigricans , established within a few years after removal of the sod. However, no seeds of this species have been detected in the soil below either of the successional stages. Based on the species disappearance from the established vegetation and based on the independent data of Thompson et al. (1997) an estimation of seed longevity could be made for several Red List species of wet dune slacks.

Lessons from the foot and mouth disease outbreak in the Netherlands in 2001
Frits Pluimers, A.M. AKKERMAN, WAL P. VAN DER WAL, A. Dekker +1 more
2002· Revue Scientifique et Technique de l OIE98doi:10.20506/rst.21.3.1371

The Netherlands had recently developed a new strategy for the eradication of foot and mouth disease (FMD). When FMD was confirmed in Great Britain and France, recent imports of susceptible animals from these countries were traced and preventive measures were taken. On 21 March 2001, FMD was confirmed in The Netherlands. The disease was introduced by calves which became infected at a staging post in Mayenne, France, where infected sheep from Great Britain were present. A total of 26 farms were infected. Emergency vaccination of all susceptible animals was applied. Suppressive vaccination was chosen, implying that all vaccinated animals had to be slaughtered. Ring vaccination of all susceptible animals within 2 km of an infected herd was the standard procedure. However, in the 'Noord Veluwe', vaccination had to be applied to a larger area. The last affected farm was confirmed on 22 April 2001. Emergency vaccination contained the FMD infection rapidly. The last vaccinated animal was slaughtered on 25 May 2001. Many farmers were not convinced that the killing of their healthy, vaccinated animals was justified and tried to prevent the culling, but without success. Politicians and the public at large are now strongly opposed to the large-scale slaughter of vaccinated animals should a future outbreak of FMD occur. The Office International des Epizooties (OIE: World organisation for animal health) should incorporate control of vaccinated animals with non-structural protein (NSP) tests in the chapter on FMD in the International Animal Health Code.

Determination of Acetylsalicylic Acid and Salicylic Acid in Foods, Using HPLC with Fluorescence Detection
Dini P. Venema, P.C.H. Hollman, Karin P. L. T. M. Janssen, Mira Katan
1996· Journal of Agricultural and Food Chemistry97doi:10.1021/jf950458y

We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn hydrolysis to salicylic acid. With the method for free acetylsalicylic acid and salicylic acid, recovery was 95−98% for acetylsalicylic acid added to foods and 92−102% for salicylic acid. Recovery of added salicylic acid was 79−94% for the free-plus-bound salicylic acid method. The limit of detection was 0.02 mg/kg for fresh and 0.2 mg/kg for dried foods for all substances. We did not find acetylsalicylic acid in any of 30 foods previously thought to be high in salicylates. The contents of free-plus-bound salicylic acid and of free salicylic acid ranged from 0 to 1 mg/kg in vegetables and fruits and from 3 to 28 mg/kg in herbs and spices. Thus the tested foods did not contain acetylsalicylic acid and only small amounts of salicylic acid. Our data suggest that the average daily intake of acetylsalicylic acid from foods is nil and that of salicylic acid is 0−5 mg/day. Keywords: Acetylsalicylic acid; aspirin; salicylic acid; phenolic acids; foods; HPLC; determination; fluorescence detection