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381.
382.
Auxin and Ethylene Regulate Elongation Responses to Neighbor Proximity Signals Independent of Gibberellin and DELLA Proteins in Arabidopsis 下载免费PDF全文
Ronald Pierik Tanja Djakovic-Petrovic Diederik H. Keuskamp Mieke de Wit Laurentius A.C.J. Voesenek 《Plant physiology》2009,149(4):1701-1712
Plants modify growth in response to the proximity of neighbors. Among these growth adjustments are shade avoidance responses, such as enhanced elongation of stems and petioles, that help plants to reach the light and outgrow their competitors. Neighbor detection occurs through photoreceptor-mediated detection of light spectral changes (i.e. reduced red:far-red ratio [R:FR] and reduced blue light intensity). We recently showed that physiological regulation of these responses occurs through light-mediated degradation of nuclear, growth-inhibiting DELLA proteins, but this appeared to be only part of the full mechanism. Here, we present how two hormones, auxin and ethylene, coregulate DELLAs but regulate shade avoidance responses through DELLA-independent mechanisms in Arabidopsis (Arabidopsis thaliana). Auxin appears to be required for both seedling and mature plant shoot elongation responses to low blue light and low R:FR, respectively. Auxin action is increased upon exposure to low R:FR and low blue light, and auxin inhibition abolishes the elongation responses to these light cues. Ethylene action is increased during the mature plant response to low R:FR, and this growth response is abolished by ethylene insensitivity. However, ethylene is also a direct volatile neighbor detection signal that induces strong elongation in seedlings, possibly in an auxin-dependent manner. We propose that this novel ethylene and auxin control of shade avoidance interacts with DELLA abundance but also controls independent targets to regulate adaptive growth responses to surrounding vegetation. 相似文献
383.
Sylvester Elikana Anami Allan Jalemba Mgutu Catherine Taracha Griet Coussens Mansour Karimi Pierre Hilson Mieke Van Lijsebettens Jesse Machuka 《Plant Cell, Tissue and Organ Culture》2010,102(3):285-295
In Latin America and sub-Saharan Africa, tropical maize (Zea mays L.) is a major crop for human consumption. To cope with the increasing population and changing environment, there is a need
for improving tropical maize germplasm. As part of a biotechnological approach, efficient in vitro regeneration of two tropical
maize inbred lines (CML216 and CML244) was established. A number of parameters were optimized, such as age of the immature
embryos, plant media and growth regulator concentration. After 6 weeks of culture, somatic embryos that had already reached
the coleoptilar stage produced shoots after light induction and developed into fertile plants after acclimation in the soil.
The callus induction frequencies and somatic embryo-derived plantlet formation were higher when cultured with the Linsmaier
and Skoog medium than those with the Chu’s N6 basal medium. Regeneration of tropical maize shoots depended on the 2,4-dichlorophenoxyacetic
acid (2,4-D) concentration at the callus initiation stage from immature embryos. The recalcitrance of the tropical maize inbred
line TL26 to in vitro regeneration was overcome in a single-cross hybrid with the CML216 and CML244 genotypes. Remarkably,
tropical maize somatic embryos were formed at the abaxial side of the scutellum facing the medium, probably from the axis
of the immature embryos, as shown by histological sections. Upon co-cultivation, agrobacteria transiently expressed their
intronless β-glucuronidase-encoding gene at the embryogenic tissue, but not with an intron-containing gene, suggesting that
virulence genes are induced in Agrobacterium, but that subsequent steps in the T-DNA transfer are inhibited. 相似文献
384.
Affinity maturation of Fab antibody fragments by fluorescent-activated cell sorting of yeast-displayed libraries 总被引:1,自引:0,他引:1
van den Beucken T Pieters H Steukers M van der Vaart M Ladner RC Hoogenboom HR Hufton SE 《FEBS letters》2003,546(2-3):288-294
We report for the first time the affinity maturation of Fab antibody fragments using fluorescent-activated cell sorting (FACS) of yeast-displayed repertoires. A single yeast display vector which enables the inducible expression of an anchored heavy chain and a soluble light chain has been constructed. The assembly and functional display on the yeast cell surface of Fab antibodies specific for different protein targets has been demonstrated by flow cytometry and immunofluorescence microscopy. We have affinity matured a Fab antibody specific for the tetravalent antigen streptavidin using FACS of yeast-displayed repertoires diversified by error-prone polymerase chain reaction. A panel of variants with up to 10.7-fold improvement in affinity was obtained after selection. Two leading clones, R2H10 (3.2 nM) and R3B1 (5.5 nM), had mutations in light chain complementarity determining region 1 LC-CDR1 (H34R) and LC-CDR3 (Y96H or Y96F) and gave a 10.7-fold and 6.3-fold affinity improvement over the starting antibody, respectively. The ability to efficiently affinity mature Fab antibodies is an important component of the antibody development pipeline and we have shown that yeast display is an efficient method for this purpose. 相似文献
385.
Inge Van Hove Kim Lemmens Sarah Van de Velde Mieke Verslegers Lieve Moons 《Journal of neurochemistry》2012,123(2):203-216
Matrix metalloproteinases (MMPs) are a large family of proteases involved in many cell‐matrix and cell‐cell signalling processes through activation, inactivation or release of extracellular matrix (ECM) and non‐ECM molecules, such as growth factors and receptors. Uncontrolled MMP activities underlie the pathophysiology of many disorders. Also matrix metalloproteinase‐3 (MMP‐3) or stromelysin‐1 contributes to several pathologies, such as cancer, asthma and rheumatoid arthritis, and has also been associated with neurodegenerative diseases like Alzheimer's disease, Parkinson's disease and multiple sclerosis. However, based on defined MMP spatiotemporal expression patterns, the identification of novel candidate molecular targets and in vitro and in vivo studies, a beneficial role for MMPs in CNS physiology and recovery is emerging. The main purpose of this review is to shed light on the recently identified roles of MMP‐3 in normal brain development and in plasticity and regeneration after CNS injury and disease. As such, MMP‐3 is correlated with neuronal migration and neurite outgrowth and guidance in the developing CNS and contributes to synaptic plasticity and learning in the adult CNS. Moreover, a strict spatiotemporal MMP‐3 up‐regulation in the injured or diseased CNS might support remyelination and neuroprotection, as well as genesis and migration of stem cells in the damaged brain. 相似文献
386.
Boerlage-van Dijk Kirsten. Siegers Charlotte E. P. Wouters Noëmie T. A. E. Faes Miriam C. Verbunt Robert A. M. Geertman J. Hans van den Heuvel Mieke van de Meerendonk Chajja T. U. Liem Su-San Henriques Jose P. Ottervanger Jan Paul 《Netherlands heart journal》2022,30(12):541-545
Due to population ageing, the number of older and frail patients with cardiovascular disease is increasing. In the current guidelines of the European Society of Cardiology specific recommendations for this older population are missing or scarce, probably due to limited evidence concerning diagnosis and treatment of cardiovascular disease in older patients. Moreover, recommendations on shared decision making, palliative care and advanced care planning are also essential in these guidelines. In this article we evaluate the current European of Society of Cardiology guidelines (2013–2020) to determine whether specific recommendations for older patients have been included.
相似文献387.
388.
Mieke Schrooten 《The Australian journal of anthropology》2011,22(2):203-219
Starting from the observation that Brazilian history has led to the development of a very distinct system of race relations, this paper focuses on the (re)creation of ethnic divisions in a new city, Palmas, the capital of the Brazilian state Tocantins. Because the city was only founded in 1990, internal migration has heavily influenced the composition of the city’s population. The research shows that residential proximity and interaction between whites and non‐whites is largely limited to the poor neighbourhoods of the city. Subtle racism continues to exist, deriving from a way of thinking that naturalises the racial hierarchy. The absence of clearly defined racial categories and the centrality of miscegenation to the Brazilian identity complicate the further dismantling of this racist culture. 相似文献
389.
Floor Verhaeghe Lieve Bradt Mieke Van Houtte Ilse Derluyn 《Ethnic and racial studies》2017,40(15):2728-2748
Assimilation theory assumes that differences between migrants and non-migrants disappear over generations. We report on a Flemish survey study conducted with young first- (G1), second- (G2) and third- (G3) generation migrants (n?=?1,587). The results showed that G1 and G2 had lower chances of being in educational tracks preparing for higher education than non-migrants. Further, G1 and G3 migrants with a background in the oldest fifteen members of the European Union (EU15) and G1 and G2 adolescents of non-EU15 migrants ran a higher risk of being delayed in their educational trajectories. All three generations of non-EU15 migrants had lower expectations of finding a job than non-migrants. Whereas socio-economic status could explain almost all of the differences for EU15 migrants, it could not for non-EU15 migrants. This leads to the hypothesis that visible differences and distinctive names lead to assumptions about ethnic, cultural and religious affiliations that are associated with discrimination. 相似文献
390.