scholarly journals Allotetraploidization in Brachypodium May Have Led to the Dominance of One Parent’s Metabolome in Germinating Seeds

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 828
Author(s):  
Aleksandra Skalska ◽  
Elzbieta Wolny ◽  
Manfred Beckmann ◽  
John H. Doonan ◽  
Robert Hasterok ◽  
...  
Keyword(s):  
Cell Wall ◽  
Tricarboxylic Acid Cycle ◽  
Sugar Metabolism ◽  
Vital Role ◽  
Nutrient Mobilization ◽  
Cellular Events ◽  
Complex Process ◽  
Germinating Seeds ◽  
Community Standard ◽  
Ecological Range

Seed germination is a complex process during which a mature seed resumes metabolic activity to prepare for seedling growth. In this study, we performed a comparative metabolomic analysis of the embryo and endosperm using the community standard lines of three annual Brachypodium species, i.e., B. distachyon (Bd) and B. stacei (Bs) and their natural allotetraploid B. hybridum (BdBs) that has wider ecological range than the other two species. We explored how far the metabolomic impact of allotetraploidization would be observable as over-lapping changes at 4, 12, and 24 h after imbibition (HAI) with water when germination was initiated. Metabolic changes during germination were more prominent in Brachypodium embryos than in the endosperm. The embryo and endosperm metabolomes of Bs and BdBs were similar, and those of Bd were distinctive. The Bs and BdBs embryos showed increased levels of sugars and the tricarboxylic acid cycle compared to Bd, which could have been indicative of better nutrient mobilization from the endosperm. Bs and BdBs also showed higher oxalate levels that could aid nutrient transfer through altered cellular events. In Brachypodium endosperm, the thick cell wall, in addition to starch, has been suggested to be a source of nutrients to the embryo. Metabolites indicative of sugar metabolism in the endosperm of all three species were not prominent, suggesting that mobilization mostly occurred prior to 4 HAI. Hydroxycinnamic and monolignol changes in Bs and BdBs were consistent with cell wall remodeling that arose following the release of nutrients to the respective embryos. Amino acid changes in both the embryo and endosperm were broadly consistent across the species. Taking our data together, the formation of BdBs may have maintained much of the Bs metabolome in both the embryo and endosperm during the early stages of germination. In the embryo, this conserved Bs metabolome appeared to include an elevated sugar metabolism that played a vital role in germination. If these observations are confirmed in the future with more Brachypodium accessions, it would substantiate the dominance of the Bs metabolome in BdBs allotetraploidization and the use of metabolomics to suggest important adaptive changes.

Mixed-ligand copper(ii) Schiff base complexes: the vital role of co-ligands in DNA/protein interactions and cytotoxicity

2017 ◽  
Vol 41 (3) ◽  
pp. 1267-1283 ◽  
Author(s):  
Sellamuthu Kathiresan ◽  
Subramanian Mugesh ◽  
Jamespandi Annaraj ◽  
Maruthamuthu Murugan
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Schiff Base ◽  
Protein Interactions ◽  
Apoptotic Cell ◽  
Vital Role ◽  
Mixed Ligand ◽  
Schiff Base Complexes ◽  
Antibacterial Mechanism

Four new mixed-ligand copper(ii) complexes display an antibacterial mechanism of cell death via cell-wall rupture and cytotoxicity via apoptotic cell death.

Select Gram-negative Aerobic Bacteria

2012 ◽  
pp. 90-101
Author(s):  
David R. McNamara ◽  
Franklin R. Cockerill
Keyword(s):  
Cell Wall ◽  
Sepsis Syndrome ◽  
Vital Role ◽  
Klebsiella Pneumonia ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Neisseria Meningitides ◽  
A Cell ◽  
Normal Human ◽  
Specific Species

Gram-negative bacteria may be rod-shaped (bacilli), spherical (cocci), oval, helical, or filamentous. Cytoplasmic membrane is surrounded by a cell wall consisting of a peptidoglycan layer and an outer cell membrane. Gram-negative bacteria are widely distributed in the natural environment. They are commensals with many animals and play a vital role in normal human physiology as intestinal commensals. Gram-negative bacteria are the cause of various human illnesses. The gram-negative bacterial cell wall contains various lipopolysaccharide endotoxins. Endotoxins trigger intense inflammation and the sepsis syndrome during infection. Specific species of gram-negative bacteria such as Neisseria meningitides, Moraxella catarrhalis, Acinetobacter, Vibrio, Klebsiella pneumonia, Salmonella, Pseudomonas aeruginosa, and Haemophilus influenza are reviewed.

Unpacking dimensions of immersion teacher educator identity

2018 ◽  
Vol 6 (2) ◽  
pp. 218-243 ◽  
Author(s):  
Aisling Leavy ◽  
Mairéad Hourigan ◽  
T. J. Ó Ceallaigh
Keyword(s):  
Teacher Development ◽  
Professional Learning ◽  
Lesson Study ◽  
Teacher Educators ◽  
Teacher Educator ◽  
Vital Role ◽  
Professional Identities ◽  
Immersion Education ◽  
Complex Process ◽  
Study Methodology

Abstract Inadequate teacher preparation for immersion programs remains a challenge. While there is a significant dearth of research on teacher development in immersion education, research focusing on immersion teacher educators (ITEs) is even more scant. Using self-study methodology, this study explores the professional learning and experiences of three teacher educators (TEs) as they construct new professional identities as ITEs as part of engagement in Lesson Study. The paper particularly focuses on two Mathematics teacher educators (MTEs) who were newcomers to the immersion education setting. A community of practice (CoP) framework was utilised to provide insights into what Vygotsky (1987) terms the twisting path of all three TEs as they engaged in the CoP. Critical moments of defending content as priority, negotiating an integrated space, and becoming immersion-responsive were revealed. CoP played a vital role in facilitating new professional identities and illuminates in multiple ways the exclusive and complex process of becoming an ITE.

scholarly journals Regulation of sugar metabolism genes in the nitrogen-dependent susceptibility of tomato stems to Botrytis cinerea

2020 ◽  
Vol 127 (1) ◽  
pp. 143-154
Author(s):  
Nathalie Lacrampe ◽  
Félicie Lopez-Lauri ◽  
Raphaël Lugan ◽  
Sophie Colombié ◽  
Jérôme Olivares ◽  
...  
Keyword(s):  
Cell Wall ◽  
Botrytis Cinerea ◽  
Sucrose Synthase ◽  
Nitrogen Availability ◽  
Soluble Sugars ◽  
Plant Defence ◽  
Sugar Metabolism ◽  
Sugar Transporters ◽  
Expression Of Genes ◽  
Underlying Mechanisms

Abstract Background and Aims The main soluble sugars are important components of plant defence against pathogens, but the underlying mechanisms are unclear. Upon infection by Botrytis cinerea, the activation of several sugar transporters, from both plant and fungus, illustrates the struggle for carbon resources. In sink tissues, the metabolic use of the sugars mobilized in the synthesis of defence compounds or antifungal barriers is not fully understood. Methods In this study, the nitrogen-dependent variation of tomato stem susceptibility to B. cinerea was used to examine, before and throughout the course of infection, the transcriptional activity of enzymes involved in sugar metabolism. Under different nitrate nutrition regimes, the expression of genes that encode the enzymes of sugar metabolism (invertases, sucrose synthases, hexokinases, fructokinases and phosphofructokinases) was determined and sugar contents were measured before inoculation and in asymptomatic tissues surrounding the lesions after inoculation. Key Results At high nitrogen availability, decreased susceptibility was associated with the overexpression of several genes 2 d after inoculation: sucrose synthases Sl-SUS1 and Sl-SUS3, cell wall invertases Sl-LIN5 to Sl-LIN9 and some fructokinase and phosphofructokinase genes. By contrast, increased susceptibility corresponded to the early repression of several genes that encode cell wall invertase and sucrose synthase. The course of sugar contents was coherent with gene expression. Conclusions The activation of specific genes that encode sucrose synthase is required for enhanced defence. Since the overexpression of fructokinase is also associated with reduced susceptibility, it can be hypothesized that supplementary sucrose cleavage by sucrose synthases is dedicated to the production of cell wall components from UDP-glucose, or to the additional implication of fructose in the synthesis of antimicrobial compounds, or both.

scholarly journals Characterization of extracellular vesicles produced by Aspergillus fumigatus protoplasts

2020 ◽  
Author(s):  
Juliana Rizzo ◽  
Thibault Chaze ◽  
Kildare Miranda ◽  
Robert W. Roberson ◽  
Olivier Gorgette ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Extracellular Vesicles ◽  
Fungal Pathogen ◽  
Fungal Pathogens ◽  
Sugar Metabolism ◽  
Biologically Active ◽  
Thick Cell Wall ◽  
A Cell

AbstractExtracellular vesicles (EVs) are outer membranous compartments produced by yeast and mycelial forms of several fungal species. One of the difficulties to perceive the role of EVs during the fungal life is the fact that an active secretion of these EVs has not been clearly demonstrated in situ due to the presence of a thick cell wall. One alternative to have a better access to these vesicles is to use protoplasts. This approach has been investigated here with Aspergillus fumigatus, one of the most common opportunistic fungal pathogens worldwide. Analysis of regenerating protoplasts by scanning electron microscopy and fluorescence microscopy indicated the occurrence of outer membrane projections in association with surface components and the release of particles with properties resembling those of fungal EVs. EVs in culture supernatants were characterized by transmission electron microscopy and nanoparticle tracking analysis. Proteomic and glycome analysis of EVs revealed the presence of a complex array of enzymes related to lipid / sugar metabolism, pathogenic processes, and cell wall biosynthesis. Our data indicate that i) EV production is a common feature of different morphological stages of this major fungal pathogen, and ii) protoplastic EVs are a promising tool to undertake studies of vesicle functions in fungal cells.IMPORTANCEFungal cells use extracellular vesicles (EVs) to export biologically active molecules to the outer space. Since fungal cells are encaged in a thick cell wall, it is reasonable to expect that this structure might impact the vesicle-mediated molecular export. In this study, we used protoplasts of Aspergillus fumigatus, a major fungal pathogen, as a model to evaluate EV production in the absence of a cell wall. Our results demonstrated that wall-less A. fumigatus exports plasma membrane-derived EVs containing a complex combination of proteins and glycans. Our study is the first to characterize fungal EVs in the absence of a cell wall. Our results suggest that protoplasts are a promising model for functional studies of fungal vesicles.

scholarly journals A CLEM approach to access to the ultrastructure at the graft interface in Arabidopsis thaliana

2021 ◽  
Author(s):  
Clément Chambaud ◽  
Sarah Jane Cookson ◽  
Nathalie Ollat ◽  
Emmanuelle M. F. Bayer ◽  
Lysiane Brocard
Keyword(s):  
Electron Microscopy ◽  
Arabidopsis Thaliana ◽  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Light And Electron Microscopy ◽  
Three Dimensional ◽  
Cellular Events ◽  
Membrane Tethering ◽  
Secondary Plasmodesmata ◽  
Graft Interface

Despite recent progress in our understanding of the graft union formation, we still know little about the cellular events underlying the grafting process. This is partially due to the difficulty of reliably targeting the graft interface in electron microscopy to study its ultrastructure and three-dimensional architecture. To overcome this technological bottleneck, we developed a correlative light electron microscopy approach (CLEM) to study the graft interface with high ultrastructural resolution. Grafting hypocotyls of Arabidopsis thaliana lines expressing YFP or mRFP in the endoplasmic reticulum allowed the efficient targeting of the grafting interface for under light and electron microscopy. To explore the potential of our method to study sub-cellular events at the graft interface, we focused on the formation of secondary plasmodesmata (PD) between the grafted partners. We showed that 4 classes of PD were formed at the interface and that PD introgression into the call wall was initiated equally by both partners. Moreover, the success of PD formation appeared not systematic with a third of PD not spanning the cell wall entirely. Characterizing the ultrastructural characteristics of these failed PD gives us insights into the process of secondary PD biogenesis. We showed that the thinning of the cell wall and the endoplasmic reticulum-plasma membrane tethering seem to be required for the establishment of symplastic connections between the scion and the rootstock. The resolution reached in this work shows that our CLEM method offer a new scale to the study for biological processes requiring the combination of light and electron microscopy.

scholarly journals Biosynthesis and Transport of Nucleotide Sugars for Plant Hemicellulose

2021 ◽  
Vol 12 ◽  
Author(s):  
Wenjuan Zhang ◽  
Wenqi Qin ◽  
Huiling Li ◽  
Ai-min Wu
Keyword(s):  
Cell Wall ◽  
Hydrogen Bonds ◽  
Secondary Wall ◽  
Vital Role ◽  
Regulatory Mechanisms ◽  
Nucleotide Sugar ◽  
Number Of Genes ◽  
Substrate Level ◽  
Nucleotide Sugars ◽  
Specific Nucleotide

Hemicellulose is entangled with cellulose through hydrogen bonds and meanwhile acts as a bridge for the deposition of lignin monomer in the secondary wall. Therefore, hemicellulose plays a vital role in the utilization of cell wall biomass. Many advances in hemicellulose research have recently been made, and a large number of genes and their functions have been identified and verified. However, due to the diversity and complexity of hemicellulose, the biosynthesis and regulatory mechanisms are yet unknown. In this review, we summarized the types of plant hemicellulose, hemicellulose-specific nucleotide sugar substrates, key transporters, and biosynthesis pathways. This review will contribute to a better understanding of substrate-level regulation of hemicellulose synthesis.

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