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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Zeebaars paaigebieden en opgroeigebieden in Nederlandse wateren
Tulp, I.Y.M. ; Hal, R. van; Damme, C.J.G. van; Smith, S.R. - \ 2016
IMARES (Rapport / IMARES C060/16) - 35 p.
visserijbeheer - zeevisserij - visserijbeleid - visbestand - habitatbeheer - nederland - het kanaal (english channel) - kuitschieten - waddenzee - zeeuwse eilanden - boomkorvisserij - zeebaars - noordzee - rijpen - fishery management - marine fisheries - fishery policy - fishery resources - habitat management - netherlands - english channel - spawning - wadden sea - beam trawling - sea bass - north sea - maturation
De zeebaarspopulatie neemt sinds 2010 sterk af door een hoge visserij-inspanning en een lage aanwas van jonge zeebaars sinds 2008. Zeebaars is een langlevende soort die zich pas op latere leeftijd gaat voortplanten. Op een leeftijd van ca 4 jaar en met een lengte vanaf ca 42 cm (vrouwtjes) en 32 cm (mannetjes) beginnen ze paairijp te worden. De huidige minimum aanlandingsmaat van 42 cm heeft als gevolg dat veel vrouwtjes al gevangen worden voordat ze voor het eerst hebben kunnen paaien. Naast vangstbeperkende maatregelen wordt gezocht naar maatregelen ter bescherming van paai- en opgroeigebieden. Hiervoor is ecologische kennis nodig, die voor de Nederlandse wateren nog grotendeels ontbreekt. Aanwezigheid van paaiende volwassen zeebaarzen is direct bewijs voor een paaigebied. Het alternatief is om aan paaigebieden vast te stellen aan de hand van de verspreiding van eieren in een vroeg ontwikkelstadium. Een relatief groot aantal larven en juveniele zeebaars kan wijzen op het belang van een gebied als opgroeigebied. Aanbevelingen voor beleid Gezien de huidige staat van onze kennis, kunnen we nu geen steekhoudende aanbevelingen voor maatregelen gericht op bescherming van gebieden of habitats te geven. De evidentie voor paaigebieden is nog erg dun, de opgroeigebieden zijn wel redelijk bekend, maar over het relatieve belang van elk gebied voor de populatie is nog geen inzicht. Het is duidelijk dat overbevissing een probleem is gezien de ontwikkelingen in de aanlandingen en de afname in gemiddelde lengte bij aanlanding. Het is ook duidelijk dat de zeebaars die in Nederland gevangen wordt in ieder geval voor een groot deel afkomstig is uit het Kanaal en dat de visserij daar in het vroege voorjaar van grote invloed is op de hoeveelheid zeebaars, die later in het jaar in onze wateren terechtkomt. Op basis van de huidige gegevens en inzichten is een verdere inperking van de vangsten door zowel commerciële als recreatieve vissers in ieder geval een effectieve maatregel om de zeebaarsstand te vergroten. Of er in aanvulling daarop ook noodzaak is om gericht gebieden of habitats te beschermen of te verbeteren is met de huidige kennis en gegevens niet vast te stellen en kan alleen met aanvullend onderzoek worden vastgesteld.
A gene co-expression network predicts functional genes controlling the re-establishment of desiccation tolerance in germinated Arabidopsis thaliana seeds
Dias Costa, M.C. ; Righetti, K. ; Nijveen, H. ; Yazdanpanah, F. ; Ligterink, W. ; Buitink, J. ; Hilhorst, H.W.M. - \ 2015
Planta 242 (2015)2. - ISSN 0032-0935 - p. 435 - 449.
medicago-truncatula seeds - transcription factors - expression data - abiotic stress - dormancy - drought - identification - maturation - longevity - software
Main conclusion During re-establishment of desiccation tolerance (DT), early events promote initial protection and growth arrest, while late events promote stress adaptation and contribute to survival in the dry state. Mature seeds of Arabidopsis thaliana are desiccation tolerant, but they lose desiccation tolerance (DT) while progressing to germination. Yet, there is a small developmental window during which DT can be rescued by treatment with abscisic acid (ABA). To gain temporal resolution and identify relevant genes in this process, data from a time series of microarrays were used to build a gene co-expression network. The network has two regions, namely early response (ER) and late response (LR). Genes in the ER region are related to biological processes, such as dormancy, acquisition of DT and drought, amplification of signals, growth arrest and induction of protection mechanisms (such as LEA proteins). Genes in the LR region lead to inhibition of photosynthesis and primary metabolism, promote adaptation to stress conditions and contribute to seed longevity. Phenotyping of 12 hubs in relation to re-establishment of DT with T-DNA insertion lines indicated a significant increase in the ability to re-establish DT compared with the wild-type in the lines cbsx4, at3g53040 and at4g25580, suggesting the operation of redundant and compensatory mechanisms. Moreover, we show that re-establishment of DT by polyethylene glycol and ABA occurs through partially overlapping mechanisms. Our data confirm that co-expression network analysis is a valid approach to examine data from time series of transcriptome analysis, as it provides promising insights into biologically relevant relations that help to generate new information about the roles of certain genes for DT.
Early feeding and early life housing conditions influence the response towards a noninfectious lung challenge in broilers
Simon, K. ; Vries Reilingh, G. de; Bolhuis, J.E. ; Kemp, B. ; Lammers, A. - \ 2015
Poultry Science 94 (2015)9. - ISSN 0032-5791 - p. 2041 - 2048.
intestinal immune-responses - symbiotic bacteria - delayed access - laying hens - germ-free - system - colonization - performance - maturation - microbiota
Early life conditions such as feed and water availability immediately post hatch (p.h.) and housing conditions may influence immune development and therefore immune reactivity later in life. The current study addressed the consequences of a combination of these 2 early life conditions for immune reactivity, i.e., the specific antibody response towards a non-infectious lung challenge. Broiler chicks received feed and water either immediately p.h. or with a 72 h delay and were either reared in a floor or a cage system. At 4 weeks of age, chicks received either an intra-tracheally administered Escherichia coli lipopolysaccharide (LPS)/Human Serum Albumin (HuSA) challenge or a placebo, and antibody titers were measured up to day 14 after administration of the challenge. Chicks housed on the floor and which had a delayed access to feed p.h. showed the highest antibody titers against HuSA. These chicks also showed the strongest sickness response and poorest performance in response to the challenge, indicating that chicks with delayed access to feed might be more sensitive to an environment with higher antigenic pressure. In conclusion, results from the present study show that early life feeding strategy and housing conditions influence a chick's response to an immune challenge later in life. These 2 early life factors should therefore be taken into account when striving for a balance between disease resistance and performance in poultry.
Reduced seed germination in Arabidopsis over-expressing SWI/SNF2 ATPase genes
Leeggangers, H.A.C.F. ; Folta, A. ; Muras, A. ; Nap, J.P.H. ; Mlynarova, L. - \ 2015
Physiologia Plantarum 153 (2015)2. - ISSN 0031-9317 - p. 318 - 326.
thaliana - dormancy - transcription - maturation - stress - arrest - growth - rna
In the life of flowering plants, seed germination is a critical step to ensure survival into the next generation. Generally the seed prior to germination has been in a dormant state with a low rate of metabolism. In the transition from a dormant seed to a germinating seed, various epigenetic mechanisms play a regulatory role. Here, we demonstrate that the over-expression of chromatin remodeling ATPase genes (AtCHR12 or AtCHR23) reduced the frequency of seed germination in Arabidopsis thaliana up to 30% relative to the wild-type seeds. On the other hand, single loss-of-function mutations of the two genes did not affect seed germination. The reduction of germination in over-expressing mutants was more pronounced in stress conditions (salt or high temperature), showing the impact of the environment. Reduced germinations upon over-expression coincided with increased transcript levels of seed maturation genes and with reduced degradation of their mRNAs stored in dry seeds. Our results indicate that repression of AtCHR12/23 gene expression in germinating wild-type Arabidopsis seeds is required for full germination. This establishes a functional link between chromatin modifiers and regulatory networks towards seed maturation and germination.
The ER-Associated Degradation Adaptor Protein Sel1L Regulates LPL Secretion and Lipid Metabolism
Sha, H. ; Sun, S. ; Francisco, A. ; Ehrhardt, N. ; Xue, Z.Q. ; Liu, L. ; Mattijssen, F.B.J. ; Kersten, A.H. - \ 2014
Cell Metabolism 20 (2014)3. - ISSN 1550-4131 - p. 458 - 470.
reticulum-associated-degradation - endoplasmic-reticulum - lipoprotein-lipase - caenorhabditis-elegans - membrane-protein - stress - deficiency - maturation - disease - liver
Sel1L is an essential adaptor protein for the E3 ligase Hrd1 in the endoplasmic reticulum (ER)-associated degradation (ERAD), a universal quality-control system in the cell; but its physiological role remains unclear. Here we show that mice with adipocyte-specific Sel1L deficiency are resistant to diet-induced obesity and exhibit postprandial hypertriglyceridemia. Further analyses reveal that Sel1L is indispensable for the secretion of lipoprotein lipase (LPL), independent of its role in Hrd1-mediated ERAD and ER homeostasis. Sel1L physically interacts with and stabilizes the LPL maturation complex consisting of LPL and lipase maturation factor 1 (LMF1). In the absence of Sel1L, LPL is retained in the ER and forms protein aggregates, which are degraded primarily by autophagy. The Sel1L-mediated control of LPL secretion is also seen in other LPL-expressing cell types including cardiac myocytes and macrophages. Thus, our study reports a role of Sel1L in LPL secretion and systemic lipid metabolism.
Abscisic acid (ABA) sensitivity regulates desiccation tolerance in germinated Arabidopsis seeds
Maia de Oliveira, J. ; Dekkers, S.J.W. ; Dolle, M. ; Ligterink, W. ; Hilhorst, H.W.M. - \ 2014
New Phytologist 203 (2014)1. - ISSN 0028-646X - p. 81 - 93.
bzip transcription factors - medicago-truncatula seeds - 2c protein phosphatases - signal-transduction - drought tolerance - thaliana - stress - gene - maturation - expression
During germination, orthodox seeds lose their desiccation tolerance (DT) and become sensitive to extreme drying. Yet, DT can be rescued, in a well-defined developmental window, by the application of a mild osmotic stress before dehydration. A role for abscisic acid (ABA) has been implicated in this stress response and in DT re-establishment. However, the path from the sensing of an osmotic cue and its signaling to DT re-establishment is still largely unknown. Analyses of DT, ABA sensitivity, ABA content and gene expression were performed in desiccation- sensitive (DS) and desiccation-tolerant Arabidopsis thaliana seeds. Furthermore, loss and re-establishment of DT in germinated Arabidopsis seeds was studied in ABA-deficient and ABA-insensitive mutants. We demonstrate that the developmental window in which DT can be re-established correlates strongly with the window in which ABA sensitivity is still present. Using ABA biosynthesis and signaling mutants, we show that this hormone plays a key role in DT re-establishment. Surprisingly, re-establishment of DT depends on the modulation of ABA sensitivity rather than enhanced ABA content. In addition, the evaluation of several ABA-insensitive mutants, which can still produce normal desiccation-tolerant seeds, but are impaired in the re-establishment of DT, shows that the acquisition of DT during seed development is genetically different from its re-establishment during germination.
A bio-economic analysis of harvest control rules for the Northeast Arctic cod fishery
Eikeset, A.M. ; Richter, A.P. ; Dankel, D.J. ; Dunlop, E.S. ; Heino, M. ; Dieckmann, U. ; Stenseth, N.C. - \ 2013
Marine Policy 39 (2013). - ISSN 0308-597X - p. 172 - 181.
reaction norms - gadus-morhua - management - stock - economics - model - recruitment - maturation - evolution - fecundity
Harvest control rules (HCRs) have been implemented for many fisheries worldwide. However, in most instances, those HCRs are not based on the explicit feedbacks between stock properties and economic considerations. This paper develops a bio-economic model that evaluates the HCR adopted in 2004 by the Joint Norwegian-Russian Fishery Commission to manage the world's largest cod stock, Northeast Arctic cod (NEA). The model considered here is biologically and economically detailed, and is the first to compare the performance of the stock's current HCR with that of alternative HCRs derived with optimality criteria. In particular, HCRs are optimized for economic objectives including fleet profits, economic welfare, and total yield and the merging properties are analyzed. The performance of these optimal HCRs was compared with the currently used HCR. This paper show that the current HCR does in fact comes very close to maximizing profits. Furthermore, the results reveal that the HCR that maximizes profits is the most precautionary one among the considered HCRs. Finally, the HCR that maximizes yield leads to unprecautionary low levels of biomass. In these ways, the implementation of the HCR for NEA cod can be viewed as a success story that may provide valuable lessons for other fisheries
Fluctuating quota and management costs under multiannual adjustment of fish quota
Dijk, D. van; Haijema, R. ; Hendrix, E.M.T. ; Groeneveld, R.A. ; Ierland, E.C. van - \ 2013
Ecological Modelling 265 (2013). - ISSN 0304-3800 - p. 230 - 238.
north-sea plaice - pleuronectes-platessa l. - fisheries management - stock - uncertainty - sustainability - maturation - failure - trends - growth
North Sea fisheries are managed by the European Union (EU) through a system of annual quota. Due to uncertainty about future fish stocks, yearly revisions of these policies lead to fluctuation in quota, which in turn affects harvest and investment decisions of fishermen. Determination of quota requires high management costs in terms of obtaining information and negotiations between experts and policy makers. To reduce both quota fluctuation and management costs, the EU has proposed a system of multiannual quota. In this paper we study the effect of multiannual quota on quota volatility and resource rents, while accounting for management costs. We develop a bi-level stochastic dynamic programming model, where at level one, the EU determines the quota that maximizes resource rents. At level two, fishermen decide myopically on their harvest and investment levels, subject to the quota. Results show that policy makers can reduce quota volatility and improve resource rents from the fishery with multiannual quota. Important trade-offs are involved in the accomplishment of these objectives: fish stock and investments become more volatile, which leads to more overcapacity.
Cryopreservation of monocytes or differentiated immature DCs leads to an altered cytokine response to TLR agonists and microbial stimulation
Meijerink, M. ; Ulluwishewa, D. ; Anderson, R.C. ; Wells, J. - \ 2011
Journal of Immunological Methods 373 (2011)1-2. - ISSN 0022-1759 - p. 136 - 142.
dendritic cells - maturation - bacteria - expression - assay
Literature on the effects of cryopreservation and thawing of monocytes or monocyte-derived immature dendritic cells (iDCs) on the subsequent functional capacities of the DCs is limited to a few specific maturation stimuli and is focused on applications in clinical immunotherapy. Given the cardinal role of DCs in regulating tolerance and immunity at mucosal surfaces there is a growing interest in understanding the effect of stromal, microbial and probiotic signals on DC function. Therefore our aim was to investigate the effects of cryopreservation on the functional properties of DCs stimulated with bacteria or the bacterial components using a standardized method. Surface markers CD83 and CD86 were expressed at similar levels on iDCs generated from cryopreserved or freshly isolated monocytes. Cryopreservation of iDCs led to slightly decreased expression of CD86 and CD83 compared to freshly generated iDCs prepared from unfrozen cells but this did not affect the capacity of DCs to acquire fully mature characteristics after stimulation. In contrast the cytokine response to lipoteichoic acid and bacterial stimulation was altered by cryopreservation of monocytes or iDCs, particularly for IL-12p70 which was decreased up to 250 fold or not detected. Cryopreservation also decreased TNF-a and IL-1ß production in stimulated iDCs but to a lesser extent than for IL-12p70, depending on the maturation factors used. The amounts of IL-10 produced by stimulated iDCs were increased up to 3.6 fold when iDCs were cryopreserved, but decreased up to 90 fold when generated from cryopreserved monocytes. Immature DCs are often used to investigate the immunomodulatory properties of probiotics and here we show for the first time that cryopreserved monocytes and cryopreserved iDCs have a skewed cytokine response to microbial stimulation. These findings have implications for the methods used in bacterial-DC immune assays and highlight the importance of comparing different cytokines and stimuli in immune cell cryopreservation protocols
Visualization of molecular processes associated with seed dormancy and germination using MapMan
Joosen, R.V.L. ; Ligterink, W. ; Dekkers, S.J.W. ; Hilhorst, H.W.M. - \ 2011
Seed Science Research 21 (2011)2. - ISSN 0960-2585 - p. 143 - 152.
arabidopsis-thaliana - gene-expression - genomics - adaptation - maturation - endosperm - selection - release - embryo - cvi
Seed dormancy and germination involve the concerted operation of molecular and biochemical programmes. It has become feasible to study these processes in great detail, using the current methods for transcriptome, proteome and metabolome analysis. Yet, the large amounts of data generated by these methods are often dazzling and demand efficient tools for data visualization. We have used the freely available PageMan/MapMan package (http://MapMan.gabipd.org) to visualize transcriptome and metabolome changes in Arabidopsis thaliana seeds during dormancy and germination. Using this package we developed two seed-specific MapMan pathways, which efficiently capture the most important molecular processes in seeds. The results demonstrated the usefulness of the PageMan/MapMan package for seed research.
An evaluation of indices of gross pathology associated with the nematode Anguillicoloides crassus in eels
Lefebvre, F. ; Fazio, G. ; Palstra, A.P. ; Szekely, C. ; Crivelli, A.J. - \ 2011
Journal of Fish Diseases 34 (2011)1. - ISSN 0140-7775 - p. 31 - 45.
anguilla-anguilla - european eels - swim-bladder - lake balaton - dracunculoidea infection - radiodiagnostic method - swimbladder wall - japanese eel - silver eels - maturation
This study compares two alternative indices for quantifying the gross pathology of the swimbladder of eels, Anguilla anguilla (L.), infected with the nematode Anguillicoloides crassus. Two observers recorded twice the scores obtained by the two indices on the same set of 71 wild caught eels (from elver to silver eels, French Mediterranean lagoons). The Length Ratio Index (LRI), performed better than the Swimbladder Degenerative Index (SDI), in three of four predefined criteria of decision. First, the LRI better correlated with an estimate of the swimbladder volume reduction, a functional consequence of the infection (representativeness). Also, the LRI was less prone to subjectivity (inter-observer variability) and more precise (intra-observer variability), although less easy to generate (time needed for measurement/assessment). Using a sub-sample of 32 unaffected eels (showing minor if any swimbladder damage and no living worms at autopsy), we ascertained a linear relationship between the swimbladder length and the total body length, a prerequisite of isometric growth, to definitively accept the new ratio index as a valid alternative to the SDI. Also, because the LRI can be recorded on live specimens with radio-imagery (non-invasive method), we recommend its use, and provide a graph of correspondence between the SDI scores, the LRI scores and the estimated proportion of gas loss in the swimbladder
Structures of the RNA-guided surveillance complex from a bacterial immune system
Wiedenheft, B. ; Jore, M.M. ; Brouns, S.J.J. ; Oost, J. van der - \ 2011
Nature 477 (2011). - ISSN 0028-0836 - p. 486 - 489.
crispr rna - electron-microscopy - target recognition - seed sequence - prokaryotes - interference - repeats - dna - endoribonuclease - maturation
Bacteria and archaea acquire resistance to viruses and plasmids by integrating short fragments of foreign DNA into clustered regularly interspaced short palindromic repeats (CRISPRs). These repetitive loci maintain a genetic record of all prior encounters with foreign transgressors1, 2, 3, 4, 5, 6. CRISPRs are transcribed and the long primary transcript is processed into a library of short CRISPR-derived RNAs (crRNAs) that contain a unique sequence complementary to a foreign nucleic-acid challenger7, 8, 9, 10, 11, 12. In Escherichia coli, crRNAs are incorporated into a multisubunit surveillance complex called Cascade (CRISPR-associated complex for antiviral defence), which is required for protection against bacteriophages13, 14. Here we use cryo-electron microscopy to determine the subnanometre structures of Cascade before and after binding to a target sequence. These structures reveal a sea-horse-shaped architecture in which the crRNA is displayed along a helical arrangement of protein subunits that protect the crRNA from degradation while maintaining its availability for base pairing. Cascade engages invading nucleic acids through high-affinity base-pairing interactions near the 5' end of the crRNA. Base pairing extends along the crRNA, resulting in a series of short helical segments that trigger a concerted conformational change. This conformational rearrangement may serve as a signal that recruits a trans-acting nuclease (Cas3) for destruction of invading nucleic-acid sequences
Post weaning altrenogest use in sows: follicle growth, endocrine profiles and subsequent fertility
Leeuwen, J.J.J. van - \ 2011
Wageningen University. Promotor(en): Bas Kemp, co-promotor(en): Nicoline Nieuwenhuizen-Soede. - [s.l.] : S.n. - ISBN 9789085859963 - 144
zeugen - synthetische progestogenen - spenen - voortplantingsvermogen - eierstokfollikels - rijpen - endocrinologie - vruchtbaarheid - dierfysiologie - dierlijke productie - varkenshouderij - sows - synthetic progestogens - weaning - reproductive performance - ovarian follicles - maturation - endocrinology - fertility - animal physiology - animal production - pig farming

A severe negative energy balance during first lactation may result in poor reproductive performance in the second litter. Allowing the sow recovery time after weaning by inseminating the sow the second estrus after weaning (skip a heat) improves reproductive performance. Postponing estrus for a shorter period after weaning using daily altrenogest administration has also been found to influence reproductive performance. The aim of this thesis was to develop a better understanding of consequences of altrenogest after weaning for follicle development and subsequent reproductive performance. Therefore, a first experiment investigated follicle development during and after post weaning altrenogest treatments and related this to subsequent fertility. It showed that follicle size increased during altrenogest treatment (independent of dose and duration), but no effects were found on fertility parameters on day 5 of gestation. Therefore, a second experiment studiedthe effect of duration of treatment on follicle development and subsequent farrowing rate and litter size. This experiment showed again an increase in follicle size and also showed that long altrenogest treatments (15 d) improve fertility, but that shorter treatments (8 d) reduce farrowing rates in sows with large follicles at weaning. So, to prevent outgrowth of follicles before weaning a third experiment started altrenogest treatment 3 d before weaning. This did not suppress follicle growth, but fertility was improved after altrenogest treatment in primiparous sows with compromised body condition at weaning. A fourth experiment attempted to stimulate follicle growth before weaning using split-weaning (reducing litter size to the 6 smallest piglets 3 d before complete weaning) and found that split-weaning resulted in lower embryonic survival, especially in sows with large follicles at weaning or high follicle growth during treatment. Because in all experiments sows showed follicle growth during altrenogest treatment, it was suspected that LH release was not completely suppressed during altrenogest treatment. Therefore, a fifth experiment investigated LH pulsatility during the last day of altrenogest treatment and indeed showed that LH release was suppressed during only a part of the 24 h between altrenogest administrations. Finally a last experiment showed a release pattern of both FSH and estradiol that varied over the day related with the moment of daily altrenogest administration. Further, a decrease of estrogenic activity was found during the second week of post weaning altrenogest treatment, probably as a result of reduced LH responsiveness. The level of estrogenic activity was related to weight loss during lactation. Therefore, it is assumed that LH and FSH release during altrenogest treatment stimulate follicle growth, but that levels are not high enough to sustain outgrowth of the follicles to pre-ovulatory sizes and, as a result, follicles go into atresia after on average 5-8 d of treatment. This may explain why long altrenogest treatments (12-15 d) result in improved fertility, short altrenogest treatments (3-4 d) have little effect on fertility and intermediate altrenogest treatments (5-8 d) may reduce fertility. As there is large variation between sows (parity, lactational burden, follicle size), this may also affect their response to altrenogest treatment. In general, to improve reproductive performance, it is recommended to start altrenogest treatment 3-6 h before weaning and to apply intermediate treatments (5-8 d) only in primiparous sows that suffered a severe lactational burden and are in low body condition at weaning.

Postnatal development of depth-dependent collagen density in ovine articular cartilage
Turnhout, M.C. van; Schipper, H. ; Lagen, B. van; Zuilhof, H. ; Kranenbarg, S. ; Leeuwen, J.L. van - \ 2010
BMC Developmental Biology 10 (2010). - ISSN 1471-213X - 12 p.
rabbit knee-joint - functional adaptation - mechanical-properties - fibrillar collagens - network - proteoglycan - architecture - chondrocyte - maturation - anisotropy
Articular cartilage (AC) is the layer of tissue that covers the articulating ends of the bones in diarthrodial joints. Adult AC is characterised by a depth-dependent composition and structure of the extracellular matrix that results in depth-dependent mechanical properties, important for the functions of adult AC. Collagen is the most abundant solid component and it affects the mechanical behaviour of AC. The current objective is to quantify the postnatal development of depth-dependent collagen density in sheep (Ovis aries) AC between birth and maturity. We use Fourier transform infra-red micro-spectroscopy to investigate collagen density in 48 sheep divided over ten sample points between birth (stillborn) and maturity (72 weeks). In each animal, we investigate six anatomical sites (caudal, distal and rostral locations at the medial and lateral side of the joint) in the distal metacarpus of a fore leg and a hind leg.
Natural variation for seed dormancy in Arabidopsis is regulated by additive genetic and molecular pathways
Bentsink, L. ; Hanson, J. ; Hanhart, C.J. ; Blankestijn-de Vries, M.H.C. ; Coltrane, C. ; Keizer, P. ; El-Lithy, M.E.M. ; Alonso-Blanco, C. ; Andres, M.T. de; Reymond, M. ; Eeuwijk, F.A. van; Smeekens, S. ; Koornneef, M. - \ 2010
Proceedings of the National Academy of Sciences of the United States of America 107 (2010)9. - ISSN 0027-8424 - p. 4264 - 4269.
quantitative trait loci - inbred-line populations - allelic variation - qtl analysis - germination - thaliana - cvi - maturation - release - ler
Timing of germination is presumably under strong natural selection as it determines the environmental conditions in which a plant germinates and initiates its postembryonic life cycle. To investigate how seed dormancy is controlled, quantitative trait loci (QTL) analyses has been performed in six Arabidopsis thaliana recombinant inbred line populations by analyzing them simultaneously using a mixed model QTL approach. The recombinant inbred line populations were derived from crosses between the reference accession Landsberg erecta (Ler) and accessions from different world regions. In total, 11 delay of germination (DOG) QTL have been identified, and nine of them have been confirmed by near isogenic lines (NILs). The absence of strong epistatic interactions between the different DOG loci suggests that they affect dormancy mainly by distinct genetic pathways. This was confirmed by analyzing the transcriptome of freshly harvested dry seeds of five different DOG NILs. All five DOG NILs showed discernible and different expression patterns compared with the expression of their genetic background Ler. The genes identified in the different DOG NILs represent largely different gene ontology profiles. It is proposed that natural variation for seed dormancy in Arabidopsis is mainly controlled by different additive genetic and molecular pathways rather than epistatic interactions, indicating the involvement of several independent pathways
Evolutionary effects of fishing and implications for sustainable management: a case study of North Seas plaice and sole
Mollet, F.M. - \ 2010
Wageningen University. Promotor(en): Adriaan Rijnsdorp. - [S.l. : S.n. - ISBN 9789085856139 - 202
schol - tong (vis) - visserij - vis vangen - evolutie - rijpen - groei - voortplanting - levensgeschiedenis - kenmerken - adaptatie - visserijbeheer - duurzaamheid (sustainability) - zeevisserij - experimentele evolutie - plaice - dover soles - fisheries - fishing - evolution - maturation - growth - reproduction - life history - traits - adaptation - fishery management - sustainability - marine fisheries - experimental evolution
Requirements for ER-Arrest and Sequential Exit to the Golgi of Tomato Spotted Wilt Virus Glycoproteins
Ribeiro, D.M.O.G. ; Goldbach, R.W. ; Kormelink, R.J.M. - \ 2009
Traffic 10 (2009)6. - ISSN 1398-9219 - p. 664 - 672.
plant endoplasmic-reticulum - green fluorescent protein - copii vesicle formation - brefeldin-a - transient association - soluble-proteins - export sites - cells - tobacco - maturation
The envelope glycoproteins Gn and Gc are major determinants in the assembly of Tomato spotted wilt virus (TSWV) particles at the Golgi complex. In this article, the ER-arrest of singly expressed Gc and the transport of both glycoproteins to the Golgi upon co-expression have been analyzed. While preliminary results suggest that the arrest of Gc at the ER (endoplasmic reticulum) did not appear to result from improper folding, transient expression of chimeric Gc, in which the transmembrane domain (TMD) and/or cytoplasmic tail (CT) were swapped for those from Gn, showed that the TMD of Gn was sufficient to allow ER-exit and transport to the Golgi. Expression of both glycoproteins in the presence of overexpressed Sar1p-specific guanosine nucleotide exchange factor Sec 12p, resulted in ER-retention demonstrating that the viral glycoproteins are transported to the Golgi in a COPII (coat protein II)-dependent manner. Inhibition of ER-Golgi transport by brefeldin A (BFA) had a similar effect on the localization of Gn. However, inhibition of ER (endoplasmic reticulum) to Golgi transport of co-expressed Gc and Gn by overexpression of Sec 12p or by BFA revealed distinct localization patterns, i.e. diffuse ER localization versus concentration at specific spots
Natural modifiers of seed longevity in the Arabidopsis mutants abscisic acid insensitive3-5 (abi3-5) and leafy cotyledon1-3 (lec1-3)
Sugliani, M.R.L. ; Rajjou, L. ; Clerkx, E.J.M. ; Koornneef, M. ; Soppe, W.J.J. - \ 2009
New Phytologist 184 (2009)4. - ISSN 0028-646X - p. 898 - 908.
heat-shock proteins - desiccation tolerance - genetic-variation - allelic variation - leafy cotyledon1 - germination - maturation - thaliana - expression - networks
• Seed longevity is an important trait in many crops and is essential for the success of most land plant species. Current knowledge of its molecular regulation is limited. The Arabidopsis mutants abscisic acid insensitive3-5 (abi3-5) and leafy cotyledon1-3 (lec1-3) have impaired seed maturation and quickly lose seed viability. abi3-5 and lec1-3 were used as sensitized genetic backgrounds for the study of seed longevity. • We exploited the natural variation of Arabidopsis to create introgression lines from the Seis am Schlern and Shahdara accessions in, respectively, the abi3-5 and lec1-3 backgrounds. These lines carry natural modifiers of the abi3 and lec1 phenotypes. Longevity tests and a proteomic analysis were conducted to describe the seed physiology of each line. • The modifier lines showed improved seed longevity. The Shahdara modifiers can partially re-establish the seed developmental programs controlled by LEC1 and restore the accumulation of seed storage proteins that are reduced in abi3-5 and lec1-3. • The isolation and characterization of natural modifiers of the seed maturation mutants abi3-5 and lec1-3, and the analysis of their seed proteomes, advance our current understanding of seed longevity
Fecundity, atresia, and spawning strategies of Atlantic herring (Clupea harengus)
Damme, C.J.G. van; Dickey-Collas, M. ; Rijnsdorp, A.D. ; Kjesdu, O.S. - \ 2009
Canadian Journal of Fisheries and Aquatic Sciences 66 (2009)12. - ISSN 0706-652X - p. 2130 - 2141.
north-sea - reproductive strategies - potential fecundity - gadus-morhua - rapid method - irish sea - cod - populations - maturation - weight
Atlantic herring (Clupea harengus) have contrasting spawning strategies, with apparently genetically similar fish “choosing” different spawning seasons, different egg sizes, and different spawning areas. In the North Sea, both autumn- and winter-spawning herring share the same summer feeding area but have different spawning areas. Females of both spawning types start their oocyte development in April–May. Oocyte development is influenced by the body energy content; during the maturation cycle, fecundity is down-regulated through atresia in relation to the actual body condition. Hence, fecundity estimates must account for the relative time of sampling. The down-regulation over the whole maturation period is approximately 20% in autumn- and 50% in winter-spawning herring. The development of the oocytes is the same for both spawning strategies until autumn when autumn spawners spawn a larger number of small eggs. In winter spawners, oocyte development and down-regulation of fecundity continues, resulting in larger eggs and lower number spawned. In theory, autumn and winter spawners could therefore switch spawning strategies, indicating a high level of reproductive plasticity
Transcription analysis of apple fruit development using cDNA microarrays
Soglio, V. ; Costa, F. ; Molthoff, J.W. ; Weemen-Hendriks, M. ; Schouten, H.J. ; Gianfranceschi, L. - \ 2009
Tree Genetics and Genomes 5 (2009)4. - ISSN 1614-2942 - p. 685 - 698.
expressed-sequence-tags - beta-cyanoalanine synthase - malus-pumila mill. - gene-expression - ethylene biosynthesis - domestica borkh. - tomato - model - identification - maturation
The knowledge of the molecular mechanisms underlying fruit quality traits is fundamental to devise efficient marker-assisted selection strategies and to improve apple breeding. In this study, cDNA microarray technology was used to identify genes whose expression changes during fruit development and maturation thus potentially involved in fruit quality traits. The expression profile of 1,536 transcripts was analysed by microarray hybridisation. A total of 177 genes resulted to be differentially expressed in at least one of the developmental stages considered. Gene ontology annotation was employed to univocally describe gene function, while cluster analysis allowed grouping genes according to their expression profile. An overview of the transcriptional changes and of the metabolic pathways involved in fruit development was obtained. As expected, August and September are the two months where the largest number of differentially expressed genes was observed. In particular, 85 genes resulted to be up-regulated in September. Even though most of the differentially expressed genes are involved in primary metabolism, several other interesting functions were detected and will be presented.
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