193 research outputs found
Cereal landraces genetic resources in worldwide GeneBanks. A review
Since the dawn of agriculture, cereal landraces
have been the staples for food production worldwide, but
their use dramatically declined in the 2nd half of the last
century, replaced by modern cultivars. In most parts of the
world, landraces are one of the most threatened components
of agrobiodiversity, facing the risk of genetic erosion and
extinction. Since landraces have a tremendous potential in
the development of new cultivars adapted to changing environmental
conditions, GeneBanks holding their genetic
resources potentially play an important role in supporting sustainable agriculture. This work reviews the current
knowledge on cereal landraces maintained in GeneBanks
and highlights the strengths and weaknesses of existing
information about their taxonomy, origin, structure, threats,
sampling methodologies and conservation and GeneBanks’
documentation and management. An overview of major
collections of cereal landraces is presented, using the information
available in global metadatabase systems. This review
on winter cereal landrace conservation focuses on: (1)
traditional role of GeneBanks is evolving beyond their original
purpose to conserve plant materials for breeding programmes.
Today’s GeneBank users are interested in
landraces’ history, agro-ecology and traditional knowledge
associated with their use, in addition to germplasm traits. (2)
GeneBanks therefore need to actively share their germplasm
collections’ information using different channels, to promote
unlimited and effective use of these materials for the
further development of sustainable agriculture. (3) Access to
information on the 7.4 million accessions conserved in
GeneBanks worldwide, of which cereal accessions account
for nearly 45 %, particularly information on cereal landraces
(24 % of wheat, 23 % of barley, 14 % of oats and 29 % of
rye accessions), is often not easily available to potential
users, mainly due to the lack of consistent or compatible
documentation systems, their structure and registration. (4)
Enhancing the sustainable use of landraces maintained in
germplasm collections through the effective application of
recent advances in landrace knowledge (origin, structure
and traits) and documentation using the internet tools and
data providing networks, including the use of molecular and
biotechnological tools for the material screening and detection
of agronomic traits. (5) Cereal landraces cannot be
exclusively conserved as seed samples maintained under
ex situ conditions in GeneBanks. The enormous contribution
of farmers in maintaining the crop and landraces diversity is recognised. Sharing of benefits and raising
awareness of the value of cereal landraces are the most
effective ways to promote their conservation and to ensure
their continued availability and sustainable use. (6)
Evaluation of costs and economic benefits attributed to
sustainable use of cereal landraces conserved in the
GeneBanks requires comprehensive studies conducted on a
case-by-case basis, that take into consideration species/crop
resources, conservation conditions and quality and
GeneBank location and functions.This work was support by the European
Community, through the INTERREG IIIB and MAC programmes,
research projects Germobanco Agrícola da Macaronesia and
AGRICOMAC. This paper was edited by Olga Spellman (Bioversity
International)info:eu-repo/semantics/publishedVersio
A Cell Cycle Role for the Epigenetic Factor CTCF-L/BORIS
CTCF is a ubiquitous epigenetic regulator that has been proposed as a master keeper of chromatin organisation. CTCF-like,
or BORIS, is thought to antagonise CTCF and has been found in normal testis, ovary and a large variety of tumour cells. The
cellular function of BORIS remains intriguing although it might be involved in developmental reprogramming of gene
expression patterns. We here unravel the expression of CTCF and BORIS proteins throughout human epidermis. While CTCF
is widely distributed within the nucleus, BORIS is confined to the nucleolus and other euchromatin domains. Nascent RNA
experiments in primary keratinocytes revealed that endogenous BORIS is present in active transcription sites. Interestingly,
BORIS also localises to interphase centrosomes suggesting a role in the cell cycle. Blocking the cell cycle at S phase or
mitosis, or causing DNA damage, produced a striking accumulation of BORIS. Consistently, ectopic expression of wild type
or GFP- BORIS provoked a higher rate of S phase cells as well as genomic instability by mitosis failure. Furthermore, downregulation
of endogenous BORIS by specific shRNAs inhibited both RNA transcription and cell cycle progression. The results
altogether suggest a role for BORIS in coordinating S phase events with mitosis
The Centrosomal Kinase Plk1 Localizes to the Transition Zone of Primary Cilia and Induces Phosphorylation of Nephrocystin-1
Polo-like kinase (Plk1) plays a central role in regulating the cell cycle. Plk1-mediated phosphorylation is essential for centrosome maturation, and for numerous mitotic events. Although Plk1 localizes to multiple subcellular sites, a major site of action is the centrosomes, which supports mitotic functions in control of bipolar spindle formation. In G0 or G1 untransformed cells, the centriolar core of the centrosome differentiates into the basal body of the primary cilium. Primary cilia are antenna-like sensory organelles dynamically regulated during the cell cycle. Whether Plk1 has a role in ciliary biology has never been studied. Nephrocystin-1 (NPHP1) is a ciliary protein; loss of NPHP1 in humans causes nephronophthisis (NPH), an autosomal-recessive cystic kidney disease. We here demonstrate that Plk1 colocalizes with nephrocystin-1 to the transition zone of primary cilia in epithelial cells. Plk1 co-immunoprecipitates with NPHP1, suggesting it is part of the nephrocystin protein complex. We identified a candidate Plk1 phosphorylation motif (D/E-X-S/T-φ-X-D/E) in nephrocystin-1, and demonstrated in vitro that Plk1 phosphorylates the nephrocystin N-terminus, which includes the specific PLK1 phosphorylation motif. Further, induced disassembly of primary cilia rapidly evoked Plk1 kinase activity, while small molecule inhibition of Plk1 activity or RNAi-mediated downregulation of Plk1 limited the first and second phase of ciliary disassembly. These data identify Plk1 as a novel transition zone signaling protein, suggest a function of Plk1 in cilia dynamics, and link Plk1 to the pathogenesis of NPH and potentially other cystic kidney diseases
Centrioles: active players or passengers during mitosis?
Centrioles are cylinders made of nine microtubule (MT) triplets present in many eukaryotes. Early studies, where centrosomes were seen at the poles of the mitotic spindle led to their coining as “the organ for cell division”. However, a variety of subsequent observational and functional studies showed that centrosomes might not always be essential for mitosis. Here we review the arguments in this debate. We describe the centriole structure and its distribution in the eukaryotic tree of life and clarify its role in the organization of the centrosome and cilia, with an historical perspective. An important aspect of the debate addressed in this review is how centrioles are inherited and the role of the spindle in this process. In particular, germline inheritance of centrosomes, such as their de novo formation in parthenogenetic species, poses many interesting questions. We finish by discussing the most likely functions of centrioles and laying out new research avenues
Cyanomethylene-bis(phosphonate)-Based Lanthanide Complexes: Structural, Photophysical, and Magnetic Investigations
10 pagesInternational audienceThe syntheses, structural investigations, magnetic and photophysical properties of a series of 10 lanthanide mononuclear complexes, containing the heteroditopic ligand cyanomethylene-bis(5,5-dimethyl-2-oxo-1,3,2λ5-dioxa-phosphorinane) (L), are described. The crystallographic analyses indicate two structural types: in the first one, [LnIII(L)3(H2O)2]*H2O (Ln = La, Pr, Nd), the metal ions are eight-coordinated within a square antiprism geometry, while the second one, [LnIII(L)3(H2O)]*8H2O (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er), contains seven-coordinated LnIII ions within distorted monocapped trigonal prisms...
Three-dimensional lanthanide-organic frameworks based on di-, tetra-, and hexameric clusters
Three-dimensional lanthanide-organic frameworks formulated as (CH3)2NH2[Ln(pydc)2] · 1/2H2O [Ln3+ ) Eu3+ (1a)
or Er3+ (1b); pydc2- corresponds to the diprotonated residue of 2,5-pyridinedicarboxylic acid (H2pydc)], [Er4(OH)4(pydc)4(H2O)3] ·H2O
(2), and [PrIII
2PrIV
1.25O(OH)3(pydc)3] (3) have been isolated from typical solvothermal (1a and 1b in N,N-dimethylformamide -
DMF) and hydrothermal (2 and 3) syntheses. Materials were characterized in the solid state using single-crystal X-ray diffraction,
thermogravimetric analysis, vibrational spectroscopy (FT-IR and FT-Raman), electron microscopy, and CHN elemental analysis.
While synthesis in DMF promotes the formation of centrosymmetric dimeric units, which act as building blocks in the construction
of anionic ∞
3{[Ln(pydc)2]-} frameworks having the channels filled by the charge-balancing (CH3)2NH2
+ cations generated in situ by
the solvolysis of DMF, the use of water as the solvent medium promotes clustering of the lanthanide centers: structures of 2 and 3
contain instead tetrameric [Er4(μ3-OH)4]8+ and hexameric |Pr6(μ3-O)2(μ3-OH)6| clusters which act as the building blocks of the networks,
and are bridged by the H2-xpydcx- residues. It is demonstrated that this modular approach is reflected in the topological nature of
the materials inducing 4-, 8-, and 14-connected uninodal networks (the nodes being the centers of gravity of the clusters) with
topologies identical to those of diamond (family 1), and framework types bct (for 2) and bcu-x (for 3), respectively. The
thermogravimetric studies of compound 3 further reveal a significant weight increase between ambient temperature and 450 °C with
this being correlated with the uptake of oxygen from the surrounding environment by the praseodymium oxide inorganic core
Speciation, Luminescence, and Alkaline Fluorescence Quenching of 4-(2-methylbutyl)aminodipicolinic acid (H2MEBADPA)
4-(2-Methylbutyl)aminodipicolinic acid (H2MEBADPA) has been synthesized and fully characterized in terms of aqueous phase protonation constants (pKa\u27s) and photophysical measurements. The pKa\u27s were determined by spectrophotometric titrations, utilizing a fully sealed titration system. Photophysical measurements consisted of room temperature fluorescence and frozen solution phosphorescence as well as quantum yield determinations at various pH, which showed that only fully deprotonated MEBADPA2– is appreciably emissive. The fluorescence of MEBADPA2– has been determined to be quenched by hydroxide and methoxide anions, most likely through base-catalyzed excited-state tautomerism or proton transfer. This quenching phenomenon has been quantitatively explored through steady-state and time-resolved fluorescence measurements. Utilizing the determined pKas and quenching constants, the fluorescent intensity of MEBADPA2– has been successfully modeled as a function of pH
A Novel Role for MAPKAPK2 in Morphogenesis during Zebrafish Development
One of the earliest morphogenetic processes in the development of many animals is epiboly. In the zebrafish, epiboly ensues when the animally localized blastoderm cells spread, thin over, and enclose the vegetally localized yolk. Only a few factors are known to function in this fundamental process. We identified a maternal-effect mutant, betty boop (bbp), which displays a novel defect in epiboly, wherein the blastoderm margin constricts dramatically, precisely when half of the yolk cell is covered by the blastoderm, causing the yolk cell to burst. Whole-blastoderm transplants and mRNA microinjection rescue demonstrate that Bbp functions in the yolk cell to regulate epiboly. We positionally cloned the maternal-effect bbp mutant gene and identified it as the zebrafish homolog of the serine-threonine kinase Mitogen Activated Protein Kinase Activated Protein Kinase 2, or MAPKAPK2, which was not previously known to function in embryonic development. We show that the regulation of MAPKAPK2 is conserved and p38 MAP kinase functions upstream of MAPKAPK2 in regulating epiboly in the zebrafish embryo. Dramatic alterations in calcium dynamics, together with the massive marginal constrictive force observed in bbp mutants, indicate precocious constriction of an F-actin network within the yolk cell, which first forms at 50% epiboly and regulates epiboly progression. We show that MAPKAPK2 activity and its regulator p38 MAPK function in the yolk cell to regulate the process of epiboly, identifying a new pathway regulating this cell movement process. We postulate that a p38 MAPKAPK2 kinase cascade modulates the activity of F-actin at the yolk cell margin circumference allowing the gradual closure of the blastopore as epiboly progresses
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