Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Impact of Cereal Seed Sprouting on Its Nutritional and Technological Properties : A Critical Review
Lemmens, Elien ; Moroni, Alice V. ; Pagand, Jennifer ; Heirbaut, Pieter ; Ritala, Anneli ; Karlen, Yann ; Kim-Anne, L. ; Broeck, Hetty C. van den; Brouns, Fred J.P.H. ; Brier, Niels De; Delcour, Jan A. - \ 2018
Comprehensive reviews in food science and food safety (2018). - ISSN 1541-4337
cereal - germination - malting - sprouting - sprouts

Sprouting induces activation and de novo synthesis of hydrolytic enzymes that make nutrients available for plant growth and development. Consumption of sprouted grains is suggested to be beneficial for human health. Positive consumer perceptions about sprouted cereals have resulted in new food and beverage product launches. However, because there is no generally accepted definition of “sprouting,” it is unclear when grains are to be called sprouted. Moreover, guidelines about how much sprouted grain material food products should contain to exert health benefits are currently lacking. Accordingly, there is no regulatory base to develop appropriate food labeling for “sprouted foods.” This review describes the nutritional and technological properties of sprouted grains in relation to processing conditions and provides guidelines to optimize sprouting practices in order to maximize nutritive value. Relatively long sprouting times (3 to 5 days) and/or high processing temperatures (25 to 35 °C) are needed to maximize the de novo synthesis and/or release of plant bioactive compounds. Nutrient compositional changes resulting from sprouting are often associated with health benefits. However, supportive data from clinical studies are very scarce, and at present it is impossible to draw any conclusion on health benefits of sprouted cereals. Finally, grains sprouted under the above-mentioned conditions are generally unfit for use in traditional food processing and it is challenging to use sprouted grains as ingredients without compromising their nutrient content. The present review provides a basis for better defining what “sprouting” is, and to help further research and development efforts in this field as well as future food regulations development.

Mass Spectrometric Characterization of Benzoxazinoid Glycosides from Rhizopus-Elicited Wheat (Triticum aestivum) Seedlings
Bruijn, Wouter J.C. de; Vincken, Jean Paul ; Duran, Katharina ; Gruppen, Harry - \ 2016
Journal of Agricultural and Food Chemistry 64 (2016)32. - ISSN 0021-8561 - p. 6267 - 6276.
benzoxazinoid classification - cereal grain - elicitation - germination - LC-MS - phytoalexin - plant defense - Rhizopus oryzae

Benzoxazinoids function as defense compounds and have been suggested to possess health-promoting effects. In this work, the mass spectrometric behavior of benzoxazinoids from the classes benzoxazin-3-ones (with subclasses lactams, hydroxamic acids, and methyl derivatives) and benzoxazolinones was studied. Wheat seeds were germinated with simultaneous elicitation by Rhizopus. The seedling extract was screened for the presence of benzoxazinoid (glycosides) using reversed-phase ultra-high-performance liquid chromatography with photodiode array detection coupled in line to multiple-stage mass spectrometry (RP-UHPLC-PDA-MSn). Benzoxazin-3-ones from the different subclasses showed distinctly different ionization and fragmentation behaviors. These features were incorporated into a newly proposed decision guideline to aid the classification of benzoxazinoids. Glycosides of the methyl derivative 2-hydroxy-4-methoxy-1,4-benzoxazin-3-one were tentatively identified for the first time in wheat. We conclude that wheat seedlings germinated with simultaneous fungal elicitation contain a diverse array of benzoxazinoids, mainly constituted by benzoxazin-3-one glycosides.

Post-embryonic Hourglass Patterns Mark Ontogenetic Transitions in Plant Development
Drost, Hajk Georg ; Bellstädt, Julia ; Ó'Maoiléidigh, Diarmuid S. ; Silva, Anderson T. ; Gabel, Alexander ; Weinholdt, Claus ; Ryan, Patrick T. ; Dekkers, Bas J.W. ; Bentsink, Leónie ; Hilhorst, Henk W.M. ; Ligterink, Wilco ; Wellmer, Frank ; Grosse, Ivo ; Quint, Marcel - \ 2016
Molecular Biology and Evolution 33 (2016)5. - ISSN 0737-4038 - p. 1158 - 1163.
developmental hourglass - floral transition - germination - plant development - transcriptomics

The historic developmental hourglass concept depicts the convergence of animal embryos to a common form during the phylotypic period. Recently, it has been shown that a transcriptomic hourglass is associated with this morphological pattern, consistent with the idea of underlying selective constraints due to intense molecular interactions during body plan establishment. Although plants do not exhibit a morphological hourglass during embryogenesis, a transcriptomic hourglass has nevertheless been identified in the model plant Arabidopsis thaliana. Here, we investigated whether plant hourglass patterns are also found postembryonically. We found that the two main phase changes during the life cycle of Arabidopsis, from embryonic to vegetative and from vegetative to reproductive development, are associated with transcriptomic hourglass patterns. In contrast, flower development, a process dominated by organ formation, is not. This suggests that plant hourglass patterns are decoupled from organogenesis and body plan establishment. Instead, they may reflect general transitions through organizational checkpoints.

Data from: Locomotion during digestion changes current estimates of seed dispersal kernels by fish
Leeuwen, C.H.A. van; Beukeboom, R. ; Nolet, B.A. ; Bakker, E.S. ; Pollux, B.J.A. - \ 2015
endozoochory - germination - ichthyochory - metabolic rate - riparian plants - seed retention time - Carex - Carex acuta - Carex riparia - Cyprinus carpio
Dispersal of seeds by animals is an important mechanism regulating plant diversity, range expansions and invasions. Many birds, mammals, fish, and reptiles regularly ingest, transport and excrete viable seeds (known as endozoochory). The effectiveness of endozoochory is modelled in dispersal kernels: functions that describe seed shadows in the landscape by combining movement of animals with experimentally obtained seed retention times and survival. Currently, dispersal kernels use experimental data from resting animals, yet only moving animals disperse seeds. Although physical activity is known to affect digestive processes, little is known on how and to what extent this may influence current estimates of endozoochory. Activity may either prolong seed retention in the animal's gut (locomotion-priority mode hypothesis) or may not affect seed excretion rate (digestion-priority mode hypothesis), and may affect seed survival and germination positively or negatively. We tested how activity alters dispersal estimates in fish. We compared the seed dispersal potential of two riparian plant species (Carex acuta and C. riparia) by the common carp (Cyprinus carpio) subjected to three different activity levels: low (basal metabolic rate, BMR), medium (2×BMR), or high activity (3×BMR). Physical activity of the fish did not affect the number of intact retrieved seeds over 15 h of activity, but significantly affected seed retrieval patterns over time for both seed species. More active fish started seed excretion about 1 h later and kept excreting seeds at least 2 h longer. Effects of gut passage on germination could only be tested for C. acuta, where it reduced the percentage of germinating seeds by 22%, independent of the activity level. Seeds ingested by the fish germinated on average 3.5 days later than non-ingested control seeds. Seed retention times did not affect the timing of germination. Our results support the locomotion-priority mode hypothesis, and show that modelling dispersal kernels using parameters from inactive fish may underestimate potential dispersal distances. Because a trade-off between physical activity and digestive physiology is likely common in animals, it should be taken into account in future modelling of endozoochorous seed dispersal kernels.
Influence of food matrix on outgrowth heterogeneity of heat damaged Bacillus cereus spores
Warda, A.K. ; Besten, H.M.W. den; Sha, N. ; Abee, T. ; Nierop Groot, M.N. - \ 2015
International Journal of Food Microbiology 201 (2015). - ISSN 0168-1605 - p. 27 - 34.
cooked chilled foods - incubation-temperature - recovery medium - population heterogeneity - clostridium-perfringens - individual spores - subtilis spores - germination - resistance - atcc-14579
Spoilage of heat treated foods can be caused by the presence of surviving spore-formers. It is virtually impossible to prevent contamination at the primary production level as spores are ubiquitous present in the environment and can contaminate raw products. As a result spore inactivation treatments are widely used by food producing industries to reduce the microbial spore loads. However consumers prefer mildly processed products that have less impact on its quality and this trend steers industry towards milder preservation treatments. Such treatments may result in damaged instead of inactivated spores, and these spores may germinate, repair, and grow out, possibly leading to quality and safety issues. The ability to repair and grow out is influenced by the properties of the food matrix. In the current communication we studied the outgrowth from heat damaged Bacillus cereus ATCC 14579 spores on Anopore membrane, which allowed following outgrowth heterogeneity of individual spores on broccoli and rice-based media as well as standard and mildly acidified (pH 5.5) meat-based BHI. Rice, broccoli and BHI pH 5.5 media resulted in delayed outgrowth from untreated spores, and increased heterogeneity compared to BHI pH 7.4, with the most pronounced effect in rice media. Exposure to wet heat for 1 min at 95 °C caused 2 log inactivation and approximately 95% of the spores in the surviving fraction were damaged resulting in substantial delay in outgrowth based on the time required to reach a maximum microcolony size of 256 cells. The delay was most pronounced for heat-treated spores on broccoli medium followed by spores on rice media (both untreated and treated). Interestingly, the increase in outgrowth heterogeneity of heat treated spores on BHI pH 7.4 was more pronounced than on rice, broccoli and BHI pH 5.5 conceivably reflecting that conditions in BHI pH 7.4 better support spore damage repair. This study compares the effects of three main factors, namely heat treatment, pH of BHI and the effect of food matrix highlighting the impact of different (model) food recovery media on outgrowth efficiency and heterogeneity of non-heat-treated and heat-damaged B. cereus spores.
Effects of seed traits for the potential of seed dispersal by fish with contrasting modes of feeding
Boedeltje, G. ; Spannings, T. ; Flik, G. ; Pollux, B.J.A. ; Sibbing, F.A. ; Verberk, W.C.E.P. - \ 2015
Freshwater Biology 60 (2015)5. - ISSN 0046-5070 - p. 944 - 959.
carp cyprinus-carpio - life-history traits - common carp - digestive-tract - ruppia-maritima - wetland plants - size - fruit - germination - floodplain
For aquatic and riparian plants, the important role of fish in seed dispersal is increasingly recognised. While the propensity of seeds to disperse is known to be a function of morphological, physical and chemical traits of the seed, in the case of fish-mediated seed dispersal (ichthyochory), it is largely unknown how seed traits modulate the potential for seed ingestion and their subsequent survival through the gut. Furthermore, which seed traits are important may vary among fish species. To evaluate the role of both seed and fish traits in ichthyochory, we fed seeds of 19 aquatic and riparian plant species to fish with differing feeding mechanisms. Cyprinus carpio (common carp) has a pharyngeal ‘mill’, which it uses physically to crush hard food, while Oreochromis mossambicus (Mozambique tilapia) has only tiny oral and pharyngeal teeth and instead relies more on chemical digestion. A number of seed traits, including hardness, size and shape, were important determinants of the potential of seeds for ichthyochory. Certain traits (e.g. seed dimensions) were more important during ingestion, whereas other traits were more important for seed survival and subsequent germination (e.g. seed hardness, mucilaginous coat). Compared to controls, germination of retrieved seeds in carp was lower in 10 and higher in two plant species, whereas for tilapia, it was lower in seven and higher in three species. Overlap between these plant species was low, indicating clear difference between the fish studied in their potential for seed dispersal. Carp increased in size during the experiment and concomitant decreases in seed survival and retrieval were found, suggesting that body size and the correlated bite force is an important fish trait in ichthyochory. Overall, seed hardness, size and shape appear crucial for the survival of seeds passing through the guts of carp and tilapia. Beyond this general pattern, a greater complexity of trait-performance relationships appeared: different seed traits are involved during each of the stages of ichthyochory. Moreover, the importance of seed traits differed between carp and tilapia, with some traits having interactive and contrasting effects in both fish species. Aquatic plants with floating seeds adapted to hydrochorous dispersal were less likely to be dispersed by tilapia than plants with non-floating seeds, suggesting a dispersal trade-off between ichthyochory and hydrochory. Thus, depending on their seed characteristics, fish may offer an additional dispersal route to aquatic and riparian plants.
Inactivation of chemical and heat-resistant spores of Bacillus and Geobacillus by nitrogen cold atmospheric plasma and comparison to thermal and chemical based methods
Bokhorst-van de Veen, H. van; Xie, H. ; Esveld, D.C. ; Abee, T. ; Mastwijk, H.C. ; Nierop Groot, M.N. - \ 2015
Food Microbiology 45 (2015)part A. - ISSN 0740-0020 - p. 26 - 33.
low-temperature - gas plasma - subtilis spores - sterilization - salmonella - decontamination - microorganisms - hypochlorite - germination
Bacterial spores are resistant to severe conditions and form a challenge to eradicate from food or food packaging material. Cold atmospheric plasma (CAP) treatment is receiving more attention as potential sterilization method at relatively mild conditions but the exact mechanism of inactivation is still not fully understood. In this study, the biocidal effect by nitrogen CAP was determined for chemical (hypochlorite and hydrogen peroxide), physical (UV) and heat-resistant spores. The three different sporeformers used are Bacillus cereus a food-borne pathogen, and Bacillus atrophaeus and Geobacillus stearothermophilus that are used as biological indicators for validation of chemical sterilization and thermal processes, respectively. The different spores showed variation in their degree of inactivation by applied heat, hypochlorite, hydrogen peroxide, and UV treatments, whereas similar inactivation results were obtained with the different spores treated with nitrogen CAP. G. stearothermophilus spores displayed high resistance to heat, hypochlorite, hydrogen peroxide, while for UV treatment B. atrophaeus spores are most tolerant. Scanning electron microscopy analysis revealed distinct morphological changes for nitrogen CAP-treated B. cereus spores including etching effects and the appearance of rough spore surfaces, whereas morphology of spores treated with heat or disinfectants showed no such changes. Moreover, microscopy analysis revealed CAP-exposed B. cereus spores to turn phase grey conceivably because of water influx indicating damage of the spores, a phenomenon that was not observed for non-treated spores. In addition, data are supplied that exclude UV radiation as determinant of antimicrobial activity of nitrogen CAP. Overall, this study shows that nitrogen CAP treatment has a biocidal effect on selected Bacillus and Geobacillus spores associated with alterations in spore surface morphology and loss of spore integrity.
Prolonging the longevity of ex situ conserved seeds by storage under anoxia
Groot, S.P.C. ; Groot, L. de; Kodde, J. ; Treuren, R. van - \ 2015
Plant genetic resources: characterization and utilization 13 (2015)1. - ISSN 1479-2621 - p. 18 - 26.
long-term storage - atmospheric oxidation - lipid-peroxidation - moisture-content - dry conditions - date seed - oxygen - germination - viability - survival
Plant genetic resources are conserved by genebanks mainly in the form of seeds. In most of the cases, the dried seeds can be stored for a considerable period of time, but eventually seed deterioration results in the inability to generate healthy seedlings. Prolonging seed longevity during storage reduces the frequency of regeneration, which is beneficial from a genetic as well as a management point of view. To reduce the rate of deterioration, cool and dry storage conditions are usually practised for long-term seed storage. In spite of the growing body of evidence that seed deterioration is predominantly caused by oxidative processes, the importance of seed storage under anoxic conditions has received little attention from the genebank community. Herein, we report on the effects of anoxia on seed viability, the oxygen uptake by dry seeds in closed containers and the permeability for oxygen of various seed storage containers. Our results confirm that the ageing of dry seeds is accelerated by the presence of oxygen in the storage environment. Therefore, we recommend that genebanks store dry seeds under anoxic conditions to prolong their longevity during ex situ conservation. To reduce the initial rate of viability loss, we further recommend that the period of temporary storage after seed harvest be minimized and also that the seeds are kept during this period under controlled conditions, including anoxia.
REDUCED DORMANCY5 Encodes a Protein Phosphatase 2C That Is Required for Seed Dormancy in Arabidopsis
Xiang, Y. ; Nakabayashi, K. ; Ding, J. ; He, F. ; Bentsink, L. ; Soppe, W.J.J. - \ 2014
The Plant Cell 26 (2014)11. - ISSN 1040-4651 - p. 4362 - 4375.
rna-binding proteins - abscisic-acid - messenger-rna - pp2c phosphatases - germination - thaliana - aba - reveals - gene - mutants
Seed dormancy determines germination timing and contributes to crop production and the adaptation of natural populations to their environment. Our knowledge about its regulation is limited. In a mutagenesis screen of a highly dormant Arabidopsis thaliana line, the reduced dormancy5 (rdo5) mutant was isolated based on its strongly reduced seed dormancy. Cloning of RDO5 showed that it encodes a PP2C phosphatase. Several PP2C phosphatases belonging to clade A are involved in abscisic acid signaling and control seed dormancy. However, RDO5 does not cluster with clade A phosphatases, and abscisic acid levels and sensitivity are unaltered in the rdo5 mutant. RDO5 transcript could only be detected in seeds and was most abundant in dry seeds. RDO5 was found in cells throughout the embryo and is located in the nucleus. A transcriptome analysis revealed that several genes belonging to the conserved PUF family of RNA binding proteins, in particular Arabidopsis PUMILIO9 (APUM9) and APUM11, showed strongly enhanced transcript levels in rdo5 during seed imbibition. Further transgenic analyses indicated that APUM9 reduces seed dormancy. Interestingly, reduction of APUM transcripts by RNA interference complemented the reduced dormancy phenotype of rdo5, indicating that RDO5 functions by suppressing APUM transcript levels.
The presence of a below-ground neighbour alters within-plant seed size distribution in Phaseolus vulgaris
Chen, B. ; During, H.J. ; Vermeulen, P.J. ; Anten, N.P.R. - \ 2014
Annals of Botany 114 (2014). - ISSN 0305-7364 - p. 937 - 943.
root competition - variable environments - optimal balance - number - recognition - germination - growth - consequences - adaptation - plasticity
* Background and Aims Considerable variation in seed size commonly exists within plants, and is believed to be favoured under natural selection. This study aims to examine the extent to which seed size distribution depends on the presence of competing neighbour plants. * Methods Phaseolus vulgaris plants rooting with or without a conspecific neighbourwere grown in soil with high or low nutrient availability. Seeds were harvested at the end of the growth cycle, the total nitrogen and phosphorus invested in seed production were measured and within-plant seed size distribution was quantified using a set of statistical descriptors. * Key Results Exposure to neighbours’ roots induced significant changes in seed size distribution. Plants produced proportionally more large seeds and fewer small ones, as reflected by significant increases in minimal seed size, mean seed size, skewness and Lorenz asymmetry coefficient. These effects were different from, and in several cases opposite to, the responses when the soil nutrient level was reduced, and were significant after correction for the amount of resources invested in seed production. * Conclusions Below-ground neighbour presence affects within-plant seed size distribution in P. vulgaris. This effect appears to be non-resource-mediated, i.e. to be independent of neighbour-induced effects on resource availability. It implies that, based on current environmental cues, plants can make an anticipatory adjustment of their investment strategy in offspring as an adaptation to the local environment in the future. Key words: Anticipatory maternal effect, bet-hedging, game theory, neighbour detection, Phaseolus vulgaris, kidney bean, root competition, seed-setting, seed size variation, size inequality, skewness. INTRODUCTION A considerable degree of variation in seed size within plants is commonly observed (Michaels et al., 1988; Silvertown, 1989; Ruiz de Clavijo, 2002; Vo¨ller et al., 2012). Such variation is often interpreted as an adaptive bet-hedging strategy (Harper et al., 1970; McGinley et al., 1987; McGinley and Charnov, 1988; Venable and Brown, 1988; Geritz, 1995). Many studies also reveal that plants modify the pattern of variation (i.e. distribution) to cope with their abiotic environmental conditions (e.g. temperature, Wulff, 1986; light, Galloway, 2001; nutrients, Galloway, 2001;water, Parciak, 2002). Herewe demonstrate that seed size distribution may also be modified in response to the presence of a below-ground neighbour. Within a species, seed size (following common practice, seed size refers to seedweight in this paper) often correlates positively with the competitiveness of the offspring (e.g. Houssard and Escarre´, 1991; Eriksson, 1999; Lehtila¨ and Ehrle´n, 2005; Dubois and Cheptou, 2012). Based on the trade-off, induced by resource limitation in plants, between competition (favours large seeds) and colonization (favours a large number of small seeds), Geritz (1995) extended an optimal offspring size model (Smith and Fretwell, 1974) by considering seedling competition and using
Plant movements and climate warming: intraspecific variation in growth responses to nonlocal soils
Frenne, P. De; Coomes, D. ; Schrijver, A. De; Staelens, J. ; Alexander, J.M. ; Bernhardt-Romermann, M. ; Brunet, J. ; Chabrerie, O. ; Chiarucci, A. ; Ouden, J. den - \ 2014
New Phytologist 202 (2014)2. - ISSN 0028-646X - p. 431 - 441.
local adaptation - latitudinal gradient - vascular plants - forest herbs - nitrogen deposition - seed dispersal - range shifts - germination - colonization - temperature
Most range shift predictions focus on the dispersal phase of the colonization process. Because moving populations experience increasingly dissimilar nonclimatic environmental conditions as they track climate warming, it is also critical to test how individuals originating from contrasting thermal environments can establish in nonlocal sites. We assess the intraspecific variation in growth responses to nonlocal soils by planting a widespread grass of deciduous forests (Milium effusum) into an experimental common garden using combinations of seeds and soil sampled in 22 sites across its distributional range, and reflecting movement scenarios of up to 1600 km. Furthermore, to determine temperature and forest-structural effects, the plants and soils were experimentally warmed and shaded. We found significantly positive effects of the difference between the temperature of the sites of seed and soil collection on growth and seedling emergence rates. Migrant plants might thus encounter increasingly favourable soil conditions while tracking the isotherms towards currently ‘colder’ soils. These effects persisted under experimental warming. Rising temperatures and light availability generally enhanced plant performance. Our results suggest that abiotic and biotic soil characteristics can shape climate change-driven plant movements by affecting growth of nonlocal migrants, a mechanism which should be integrated into predictions of future range shifts.
Interaction between parental environment and genotype affects plant and seed performance in Arabidopsis
He, H. ; Souza Vidigal, D. De; Snoek, L.B. ; Schnabel, S.K. ; Nijveen, H. ; Hilhorst, H. ; Bentsink, L. - \ 2014
Journal of Experimental Botany 65 (2014)22. - ISSN 0022-0957 - p. 6603 - 6615.
sativa miller brassicaceae - abscisic-acid biosynthesis - maturation environment - drought tolerance - natural variation - key enzyme - dormancy - germination - thaliana - temperature
Seed performance after dispersal is highly dependent on parental environmental cues, especially during seed formation and maturation. Here we examine which environmental factors are the most dominant in this respect and whether their effects are dependent on the genotypes under investigation. We studied the influence of light intensity, photoperiod, temperature, nitrate, and phosphate during seed development on five plant attributes and thirteen seed attributes, using 12 Arabidopsis genotypes that have been reported to be affected in seed traits. As expected, the various environments during seed development resulted in changed plant and/or seed performances. Comparative analysis clearly indicated that, overall, temperature plays the most dominant role in both plant and seed performance, whereas light has a prominent impact on plant traits. In comparison to temperature and light, nitrate mildly affected some of the plant and seed traits while phosphate had even less influence on those traits. Moreover, clear genotype-by-environment interactions were identified. This was shown by the fact that individual genotypes responded differentially to the environmental conditions. Low temperature significantly increased seed dormancy and decreased seed longevity of NILDOG1 and cyp707a1-1, whereas low light intensity increased seed dormancy and decreased seed longevity of NILDOG3 and NILDOG6. This also indicates that different genetic and molecular pathways are involved in the plant and seed responses. By identifying environmental conditions that affect the dormancy vs longevity correlation in the same way as previously identified naturally occurring loci, we have identified selective forces that probably shaped evolution for these important seed traits.
Quantification of the impact of single and multiple mild stresses on outgrowth heterogeneity of Bacillus cereus spores
Melis, C.C.J. van; Besten, H.M.W. den; Nierop Groot, M.N. ; Abee, T. - \ 2014
International Journal of Food Microbiology 177 (2014). - ISSN 0168-1605 - p. 57 - 62.
nonproteolytic clostridium-botulinum - individual spores - heat-treatment - wet-heat - population heterogeneity - germination - food - growth - perfringens - subtilis
Outgrowth heterogeneity of bacterial spore populations complicates both prediction and efficient control of spore outgrowth. In this study, the impact of mild preservation stresses on outgrowth of Bacillus cereus ATCC 14579 spores was quantified during the first stages of outgrowth. Heterogeneity in outgrowth of heat-treated (90 °C for 10 min) and non-heat-treated germinated single spores to the maximum micro-colony stage of 256 cells was assessed by direct imaging on Anopore strips, placed on BHI plates at pH 7 and pH 5.5, without and with added NaCl or sorbic acid (HSA). At pH 7 non-heated and heat-treated germinated spores required 6 h to reach the maximum microcolony stage with limited heterogeneity, and these parameters were only slightly affected with both types of spores when incubated at pH 7 with added NaCl. Notably, the most pronounced effects were observed during outgrowth of spores at pH 5.5 without and with added NaCl or HSA. Non-heat-treated germinated spores showed again efficient outgrowth with limited heterogeneity reaching the maximum microcolony stage after 6 h at pH 5.5, which increased to 12 h and 16 h with added NaCl and HSA, respectively. In contrast, heat-treated spores displayed a strong delay between initial germination and swelling and further outgrowth at pH 5.5, resulting in large heterogeneity and low numbers of fastest growers reaching the maximum microcolony stage after 10, 12 and 24 h, without and with added NaCl or HSA, respectively. This work shows that Anopore technology provides quantitative information on the impact of combined preservation stresses on outgrowth of single spores, showing that outgrowth of germinated heat-treated spores is significantly affected at pH 5.5 with a large fraction of spores arrested in the early outgrowth stage, and with outgrowing cells showing large heterogeneity with only a small fraction committed to relatively fast outgrowth. Keywords Bacillus cereus; Spores; Outgrowth; Heterogeneity; Anopore; Stress
Nutritional characteristics of mung bean foods
Dahiya, P.K. ; Nout, M.J.R. ; Boekel, M.A.J.S. van; Khetarpaul, N. ; Grewal, R.B. ; Linnemann, A.R. - \ 2014
British Food Journal 116 (2014)6. - ISSN 0007-070X - p. 1031 - 1046.
protein digestibility - ascorbic-acid - nutrient composition - iron-absorption - phytic acid - bioavailability - phytate - antinutrients - germination - zinc
Purpose – The purpose of this paper is to address malnourishment in developing countries by a food-based approach in which locally produced and consumed foods are improved by applying food processing techniques that benefit the amount and availability of desirable nutrients. Design/methodology/approach – To facilitate this approach, this paper reports on the composition and in vitro micronutrient accessibility of 14 traditional mung bean foods from India in relation to their preparation methods. Findings – Proximate composition, in vitro mineral accessibility, phytic acid and polyphenol contents varied among the range of products. Products requiring either fermentation or germination, had higher in vitro iron, zinc and calcium accessibility. Average in vitro iron, zinc and calcium accessibility of the mung bean products were 16, 9 and 418¿mg¿kg-1 dry weight. Phytic acid and polyphenols averaged 2.1 and 1.8¿g¿kg-1 dry weight, respectively, and were negatively correlated with in vitro mineral accessibility. Practical implications – Different mung bean products (100¿g) cover 12.0-59.5, 5.2-45.6, 4.2-28.6 and 1.1-7.1 per cent of the recommended dietary allowance for protein, iron, zinc and calcium, respectively, for seven- to nine-year-old Indian children. Originality/value – This study demonstrated the wide range of traditional mung bean foods in India and presents options to tackle malnourishment by a food-based approach.
Relationship between redox potential and the emergence of three submerged macrophytes
Zuidam, B.G. van; Cazemier, M. ; Geest, G.J. van; Roijackers, R.M.M. ; Peeters, E.T.H.M. - \ 2014
Aquatic Botany 113 (2014). - ISSN 0304-3770 - p. 56 - 62.
seed banks - sediment load - zannichellia-palustris - hydrogen-sulfide - lake-sediments - western-europe - shallow lake - germination - burial - impact
Sedimentation may have large negative effects on aquatic vegetation as burial of propagules can reduce emergence. Burial changes the redox potential around the propagules and this might be the mechanism that causes the observed burial effects. We conducted a laboratory experiment to evaluate the effect of redox potential on the emergence of three aquatic macrophytes from their propagules. Different redox potential treatments were applied by burying propagules of Potamogeton pusillus and Chara cf. contraria at three different depths and with two different sediments (loamy mud and sand). Propagules of Zannichellia palustris were also buried at three depths, but only with sand. Emergence of P. pusillus and Z. palustris decreased with increasing burial depth, while burial up to 5 cm depth had almost no effect on Chara cf. contraria. Burial with sand reduced emergence of P. pusillus more than burial with loamy mud, while composition of the burial sediment did not affect Chara cf. contraria. The redox potential treatments explained emergence of P. pusillus better than burial depth or composition of the burial sediment separately. There was a strong relationship between mean emergence of P. pusillus per treatment and redox potential of the treatment. Burial caused high mortality of the non-emerged propagules of P. pusillus and Z. palustris within a relatively short period of time. Our results show that redox potential could be an important factor in causing the effect of burial on emergence. On longer time scale, sedimentation has species-specific consequences potentially leading to changes in vegetation species composition.
Ontwikkelen algoritmes voor het vaststellen van de variatie van opkomst in suikerbietenplanten
Nieuwenhuizen, A.T. ; Verwijs, B.R. - \ 2013
Wageningen : Plant Research International (Programma Precisie Landbouw ) - 23
akkerbouw - suikerbieten - precisielandbouw - sensors - kieming - gegevensanalyse - geografische informatiesystemen - arable farming - sugarbeet - precision agriculture - germination - data analysis - geographical information systems
Met behulp van camera's worden aparte beeldopnamen gemaakt. Die beelden worden geanalyseerd op het wel of niet aanwezig zijn van bietenplanten gekoppeld aan het GPS coördinaat.
Chlorophyll Fluorescence Sorting Method to Improve Quality of Capsicum Pepper Seed Lots Produced from Different Maturity Fruits
Kenanoglu, B.B. ; Demir, I. ; Jalink, H. - \ 2013
Hortscience 48 (2013)8. - ISSN 0018-5345 - p. 965 - 968.
deterioration - germination
This work was conducted to investigate the efficacy of chlorophyll fluorescence (CF) sorting to improve seed germination, seedling emergence, and vigor of seeds produced from different maturity fruits of four different cultivars. Four harvest dates from each cultivar were evaluated by harvesting orange (immature), bright red (half-mature), dark red (mature), and dark red and soft (overmature) fruits. Seeds were either sorted or nonsorted after harvesting and standard laboratory germination, seedling emergence, and controlled deterioration tests were conducted. CF sorting significantly increased laboratory germination, seedling emergence, and seed vigor. Maximum improvements were obtained from seeds harvested from half-mature and mature stages. Mean germination improvement among cultivars between CF-sorted and nonsorted seeds were 14% in the immature seeds, 11% in half-mature seeds, 6% in mature seeds, and 9% in overmature seeds. Improvements in seedling emergence were 21%, 17%, 9%, and 10% and 4%, 11%, 10%, 14% for seed vigor (CD germination) in the all maturity stages of seed lots, respectively. CF has the potential to upgrade seed quality in pepper lots as a non-destructive sorting technology.
Hot fire, cool soil
Stoof, C.R. ; Moore, D. ; Fernandes, P. ; Stoorvogel, J.J. ; Fernandes, R. ; Ferreira, A.J.D. ; Ritsema, C.J. - \ 2013
Geophysical Research Letters 40 (2013)8. - ISSN 0094-8276 - p. 1534 - 1539.
south-eastern australia - intensity - behavior - forest - temperatures - variability - erodibility - germination - california - vegetation
Wildfires greatly increase a landscape's vulnerability to flooding and erosion events by removing vegetation and changing soils. Fire damage to soil increases with increasing soil temperature, and, for fires where smoldering combustion is absent, the current understanding is that soil temperatures increase as fuel load and fire intensity increase. Here, however, we show that this understanding that is based on experiments under homogeneous conditions does not necessarily apply at the more relevant larger scale where soils, vegetation, and fire characteristics are heterogeneous. In a catchment-scale fire experiment, soils were surprisingly cool where fuel load was high and fire was hot and, conversely, soils were hot where expected to be cooler. This indicates that the greatest fire damage to soil can occur where fuel load and fire intensity are low rather than high, and has important implications for management of fire-prone areas prior to, during, and after fire events.
Impact of sorbic acid and other mild preservation stresses on germination and outgrowth of Bacillus cereus spores
Melis, C.C.J. van - \ 2013
University. Promotor(en): Tjakko Abee, co-promotor(en): Masja Nierop Groot. - Wageningen : Wageningen University - ISBN 9789461737755 - 138
bacillus cereus - sorbinezuur - behoud - kieming - kiemremmers - groei - voedselbewaring - voedselmicrobiologie - sorbic acid - preservation - germination - germination inhibitors - growth - food preservation - food microbiology

Weak organic acids such as sorbic acid, lactate, and acetic acid are widely used by the food industry as preservatives to control growth of micro-organisms. With the current trend towards milder processing of food products, opportunities arise for spore-forming spoilage and pathogenic microorganisms such as Bacillus cereus, that may survive the use of milder heating regimes. Dormant spores produced by B. cereus can survive processing conditions and their subsequent outgrowth increases the risk of premature spoilage and food safety issues. As a consequence, the use of additional preservation hurdles, such as acidification with weak organic acid additives to ensure the quality and safety of a product is important. Sorbic acid is widely used as an antimicrobial compound because of its strong inhibitory properties against bacteria and other spoilage organisms. Its effectivity has also been ascribed to its hydrophobic character, resulting in an additional mode of action not observed with other less lipophilic organic acids such as lactic acid and acetic acid. In this project the impact of sorbic acid on spore germination and outgrowth was studied at transcriptome level and was linked to the distinct phenotypic responses observed for spores exposed to different levels of sorbic acid. The various stages of spore germination and outgrowth could be recognized by distinct gene expression profiles representing either the germination phase, transition state between germination and outgrowth or outgrowing cells, respectively. A subset of genes was specifically expressed in sorbic acid-exposed germinating spores and included functions related to cell envelope, (multi) drug transporters and amino acid metabolism. At high concentrations of sorbic acid (3mM of the undisssociated form, HSA), nutrient-induced germination of B. cereus ATCC 14579 spores was completely blocked. This blockage was shown to be reversible and could be bypassed by known non-nutrient triggers that activate spores in a receptor-independent way, pointing to a possible interference of HSA with the signaling event between germinant receptors and proposed SpoVA-channels, possibly by accumulation into the spore’s inner membrane. Additional experiments with other inhibiting compounds, including organic acids and their structurally similar alcohol counterparts, showed that the lipophilic properties are an important determinant of its efficacy to block germination. Building on current knowledge on the interaction of germination-relevant protein clusters, we discuss a hypothetical model on the mode of action of sorbic acid and other short-chain lipophilic compounds in germination inhibition of B. cereus spores. In addition to the interference or even blockage of germination, sorbic acid may increase outgrowth heterogeneity when applied at lower concentrations (0.25-1.5 mM) that still allow outgrowth. The first stages of outgrowth were shown to specifically occur heterogeneously when spores were exposed to multiple stresses simultaneously. Heterogeneity effects were most pronounced for combined stress-effects where heat-treated spores were also exposed to low pH stress. Under these conditions, a large subpopulation of spores was delayed between initial germination and swelling and further outgrowth. For the food producing industry, it would be desirable to have reliable parameters to predict the behavior of surviving spores in a food product. Data presented in this thesis show that germination rate is not a good predictor for outgrowth heterogeneity when applied as a single indicator. In conclusion, the work described in this thesis strive to obtain a better understanding on the impact that preservation stresses, including (sorbic) acid stress, have on the germination and outgrowth (heterogeneity) of B. cereus spores. The results obtained in this project may contribute to the rational design of new concepts for improved food preservation and safety.

Genome-wide analysis of coordinated transcript abundance during seed development in different Brassica rapa morphotypes
Basnet, R.K. ; Moreno Pachón, N.M. ; Lin, K. ; Bucher, J. ; Visser, R.G.F. ; Maliepaard, C.A. ; Bonnema, A.B. - \ 2013
BMC Genomics 14 (2013). - ISSN 1471-2164
gene-expression profiles - false discovery rate - arabidopsis-thaliana - network analysis - prolamin-box - napus - germination - embryo - maize - plant
Brassica seeds are important as basic units of plant growth and sources of vegetable oil. Seed development is regulated by many dynamic metabolic processes controlled by complex networks of spatially and temporally expressed genes. We conducted a global microarray gene co-expression analysis by measuring transcript abundance of developing seeds from two diverse B. rapa morphotypes: a pak choi (leafy-type) and a yellow sarson (oil-type), and two of their doubled haploid (DH) progenies, (1) to study the timing of metabolic processes in developing seeds, (2) to explore the major transcriptional differences in developing seeds of the two morphotypes, and (3) to identify the optimum stage for a genetical genomics study in B. rapa seed.
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