Gains achieved by molecular approaches in the area of lignification

2001 ◽  
Vol 73 (3) ◽  
pp. 561-566 ◽  
Author(s):  
Alain-M. Boudet ◽  
Matthieu Chabannes
Keyword(s):  
Molecular Biology ◽  
Lignin Content ◽  
Ectopic Expression ◽  
Lignin Biosynthesis ◽  
Cell Types ◽  
Molecular Approaches ◽  
Regulatory Circuits ◽  
Recent Developments ◽  
Spatio Temporal ◽  
Different Cell Types

In this article we highlight the contribution of molecular biology and lignin genetic engineering toward a better understanding of lignin biosynthesis and spatio-temporal deposition of lignin. Specific examples from the literature and from our laboratory will serve to underline the chemical flexibility of lignins, the complexity of the regulatory circuits involved in their synthesis, and the specific behavior of different cell types within the xylem. We will also focus on strategies aiming to reduce the lignin content or to modify the lignin composition of plants and present their impact on plant development. We will show that the ectopic expression of a specific transgene may have a different impact, depending on the genetic background, and that plants with a severe reduction in lignin content may undergo normal development. Lignification is currently benefiting enormously from recent developments in molecular biology and transgenesis, and the progress made opens the way for future developments to study how the walls of lignified plant cells are built and organized.

scholarly journals A Spatio-Temporal Model and Inference Tools for Longitudinal Count Data on Multicolor Cell Growth

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
PuXue Qiao ◽  
Christina Mølck ◽  
Davide Ferrari ◽  
Frédéric Hollande
Keyword(s):  
Cell Growth ◽  
Image Data ◽  
Real Data ◽  
Cell Types ◽  
Spatial Autoregressive ◽  
Spatio Temporal ◽  
Different Cell Types ◽  
Temporal Interactions

AbstractMulticolor cell spatio-temporal image data have become important to investigate organ development and regeneration, malignant growth or immune responses by tracking different cell types both in vivo and in vitro. Statistical modeling of image data from common longitudinal cell experiments poses significant challenges due to the presence of complex spatio-temporal interactions between different cell types and difficulties related to measurement of single cell trajectories. Current analysis methods focus mainly on univariate cases, often not considering the spatio-temporal effects affecting cell growth between different cell populations. In this paper, we propose a conditional spatial autoregressive model to describe multivariate count cell data on the lattice, and develop inference tools. The proposed methodology is computationally tractable and enables researchers to estimate a complete statistical model of multicolor cell growth. Our methodology is applied on real experimental data where we investigate how interactions between cancer cells and fibroblasts affect their growth, which are normally present in the tumor microenvironment. We also compare the performance of our methodology to the multivariate conditional autoregressive (MCAR) model in both simulations and real data applications.

scholarly journals High-order mutants reveal an essential requirement for peroxidases but not laccases in Casparian strip lignification

2020 ◽  
Author(s):  
Nelson Rojas-Murcia ◽  
Kian Hématy ◽  
Yuree Lee ◽  
Aurélia Emonet ◽  
Robertas Ursache ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lignin Biosynthesis ◽  
Cell Types ◽  
Arabidopsis Genome ◽  
Essential Requirement ◽  
Knock Out ◽  
Homologous Genes ◽  
Casparian Strips ◽  
Different Cell Types

ABSTRACTThe invention of lignin has been at the heart of plants’ capacity to colonize land, allowing them to grow tall, transport water within their bodies and protect themselves against various stresses. Consequently, this polyphenolic polymer, that impregnates the cellulosic plant cell walls, now represents the second most abundant polymer on Earth, after cellulose itself. Yet, despite its great physiological, ecological and economical importance, our knowledge of lignin biosynthesis in vivo, especially the crucial last steps of polymerization within the cell wall, remains vague. Specifically, the respective roles and importance of the two main polymerizing enzymes classes, laccases and peroxidases have remained obscure. One reason for this lies in the very high numbers of laccases and peroxidases encoded by 17 and 73 homologous genes, respectively, in the Arabidopsis genome. Here, we have focused on a specific lignin structure, the ring-like Casparian strips (CS) within the endodermis of Arabidopsis roots. By reducing the number of possible candidate genes using cellular resolution expression and localization data and by boosting the levels of mutants that can be stacked using CRISPR/Cas9, we were able to knock-out more than half of all laccases in the Arabidopsis genome in a nonuple mutant – abolishing the vast majority of laccases with detectable endodermal-expression. Yet, we were unable to detect even slight defects in CS formation. By contrast, we were able to induce a complete absence of CS formation in a quintuple peroxidase mutant. Our findings are in stark contrast to the strong requirement of xylem vessels for laccase action and indicate that lignin in different cell types can be polymerized in very distinct ways. We speculate that cells lignify differently depending on whether they deposit lignin in a localized or ubiquitous fashion, whether they stay alive during and after lignification as well as the composition of the cell wall.

scholarly journals High-order mutants reveal an essential requirement for peroxidases but not laccases in Casparian strip lignification

2020 ◽  
Vol 117 (46) ◽  
pp. 29166-29177
Author(s):  
Nelson Rojas-Murcia ◽  
Kian Hématy ◽  
Yuree Lee ◽  
Aurélia Emonet ◽  
Robertas Ursache ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lignin Biosynthesis ◽  
Cell Types ◽  
Plant Cell Walls ◽  
Essential Requirement ◽  
Homologous Genes ◽  
Casparian Strips ◽  
Different Cell Types ◽  
Root Endodermis

Lignin has enabled plants to colonize land, grow tall, transport water within their bodies, and protect themselves against various stresses. Consequently, this polyphenolic polymer, impregnating cellulosic plant cell walls, is the second most abundant polymer on Earth. Yet, despite its great physiological, ecological, and economical importance, our knowledge of lignin biosynthesis in vivo, especially the polymerization steps within the cell wall, remains vague—specifically, the respective roles of the two polymerizing enzymes classes, laccases and peroxidases. One reason for this lies in the very high numbers of laccases and peroxidases encoded by 17 and 73 homologous genes, respectively, inArabidopsis. Here, we have focused on a specific lignin structure, the ring-like Casparian strips (CSs) within the root endodermis. By reducing candidate numbers using cellular resolution expression and localization data and by boosting stacking of mutants using CRISPR-Cas9, we mutated the majority of laccases inArabidopsisin a nonuple mutant—essentially abolishing laccases with detectable endodermal expression. Yet, we were unable to detect even slight defects in CS formation. By contrast, we were able to induce a complete absence of CS formation in a quintuple peroxidase mutant. Our findings are in stark contrast to the strong requirement of xylem vessels for laccase action and indicate that lignin in different cell types can be polymerized in very distinct ways. We speculate that cells lignify differently depending on whether lignin is localized or ubiquitous and whether cells stay alive during and after lignification, as well as the composition of the cell wall.

scholarly journals Glyoxal Does Not Preserve Cellular Proteins as Accurately as PFA: A Microscopical Survey of Epitopes

2019 ◽  
Author(s):  
Ferda Topal Celikkan ◽  
Ceren Mungan ◽  
Merve Sucu ◽  
Fatma Uysal ◽  
Selda Kahveci ◽  
...  
Keyword(s):  
Cellular Localization ◽  
Super Resolution ◽  
Cell Types ◽  
Cellular Proteins ◽  
Human Stem Cells ◽  
Cellular Targets ◽  
Molecular Alterations ◽  
Recent Developments ◽  
Spatio Temporal ◽  
Fixed Cell

AbstractChemical fixation is one of the most critical steps to retaining cellular targets as naturally as possible. Recent developments in microscopy allow sophisticated detection and measuring techniques with which spatio-temporal molecular alterations is conceivable. Here, we document the fixation competence of glyoxal (Gly), a less-toxic dialdehyde molecule, and paraformaldehyde (PFA) side-by-side (with or without Triton-X 100 permealization) in live- and fixed-cell preparations including human stem cells, spermatozoa, mouse oocytes/embryos using super-resolution microscopy. Although Gly seemed to act faster than PFA, catastrophic consequences were found not acceptable, especially in oocytes and embryos. Due to cell lysate and immunocytochemistry surveys, it was obvious that PFA is superior to Gly in retaining cellular proteins in situ with little/no background staining. In many samples, PFA revealed more reliable and consistent results regarding the protein quantity and cellular localization corresponding to previously defined patterns in the literature. Although the use of Gly is beneficial as indicated by previous reports, we concluded that it does not meet the requirement for proper fixation, at least for the tested cell types and proteins.

scholarly journals Distinct and Overlapping Functions of Miscanthus sinensis MYB Transcription Factors SCM1 and MYB103 in Lignin Biosynthesis

2021 ◽  
Vol 22 (22) ◽  
pp. 12395
Author(s):  
Philippe Golfier ◽  
Olga Ermakova ◽  
Faride Unda ◽  
Emily K. Murphy ◽  
Jianbo Xie ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Secondary Cell Wall ◽  
Target Genes ◽  
Lignin Content ◽  
Ectopic Expression ◽  
Lignin Biosynthesis ◽  
Miscanthus Sinensis ◽  
Growth Stages ◽  
Transcriptional Responses

Cell wall recalcitrance is a major constraint for the exploitation of lignocellulosic biomass as a renewable resource for energy and bio-based products. Transcriptional regulators of the lignin biosynthetic pathway represent promising targets for tailoring lignin content and composition in plant secondary cell walls. However, knowledge about the transcriptional regulation of lignin biosynthesis in lignocellulosic feedstocks, such as Miscanthus, is limited. In Miscanthus leaves, MsSCM1 and MsMYB103 are expressed at growth stages associated with lignification. The ectopic expression of MsSCM1 and MsMYB103 in N. benthamiana leaves was sufficient to trigger secondary cell wall deposition with distinct sugar and lignin compositions. Moreover, RNA-seq analysis revealed that the transcriptional responses to MsSCM1 and MsMYB103 overexpression showed an extensive overlap with the response to the NAC master transcription factor MsSND1, but were distinct from each other, underscoring the inherent complexity of secondary cell wall formation. Furthermore, conserved and previously described promoter elements as well as novel and specific motifs could be identified from the target genes of the three transcription factors. Together, MsSCM1 and MsMYB103 represent interesting targets for manipulations of lignin content and composition in Miscanthus towards a tailored biomass.

scholarly journals Recent Developments and Applications of Single-Cell RNA Sequencing Technology in Cell Classification

2021 ◽  
Vol 2 (12) ◽  
pp. 1283-1290
Author(s):  
Safir Ullah Khan ◽  
Munir Ullah Khan
Keyword(s):  
Single Cell ◽  
Rna Sequencing ◽  
Clinical Medicine ◽  
Cell Types ◽  
Sequencing Platform ◽  
Single Cell Rna Sequencing ◽  
Recent Developments ◽  
A New Technique ◽  
Multicellular Organisms ◽  
Different Cell Types

Multicellular organisms have many cell types and are complex, and heterogeneity is common among cells. Single-Cell RNA Sequencing (scRNA-SEQ) is a new technique for studying the transcriptional activity of a single cell that is still in its early stages of development. It generates transcriptional profiles from thousands of parallel cells to reveal the differential expression of individual cell genomes. They reflect the heterogeneity between cells to identify different cell types and form cell maps of tissues or organs, which play an essential role in biology and clinical medicine. Based on the introduction and comparison of the scRNA-SEQ sequencing platform, this paper focuses on the application of scRNA-SEQ in the exploration of cell types in the nervous system and immune system and summarizes the research results of the combination of scRNA-SEQ and spatial transcriptome technology.

scholarly journals Programming cell growth into different cluster shapes using diffusible signals

2020 ◽  
Author(s):  
Yipei Guo ◽  
Mor Nitzan ◽  
Michael P. Brenner
Keyword(s):  
Growth Regulators ◽  
Growth Inhibitor ◽  
Spatial Arrangement ◽  
Cell Types ◽  
Growth Inhibitors ◽  
Genetic Circuits ◽  
Regulatory Circuits ◽  
Differential Gene ◽  
Different Shapes ◽  
Different Cell Types

Recent advances in genetic engineering technologies has made it possible to construct artificial genetic circuits and use them to control how cells respond to their surroundings. This has been used to generate spatial patterns of differential gene expression. In addition to the spatial arrangement of different cell types, another important aspect of spatial structure lies in the overall shape of the group of cells. However, the question of how cells can be programmed, and how complex the rules need to be, to achieve a desired tissue morphology has received less attention. In this paper, we attempt to address these questions by developing a mathematical model to study how cells can use diffusion-mediated local rules to grow into clusters with different shapes. Within our model, cells are allowed to secrete diffusible chemicals which can either directly regulate the growth rate of cells (‘growth regulator’), or indirectly affect growth by changing the secretion rate or the effect of other growth regulators. We find that (1) a single growth inhibitor can be used to grow a rod-like structure, (2) multiple growth regulators are required to grow multiple protrusions, and (3) the length and shape of each protrusion can be controlled using growth-threshold regulators. Based on these regulatory schemes, we also postulate how the range of achievable structures scales with the number of signals: (A) the maximum possible number of protrusions increases exponentially with the number of growth inhibitors involved, and (B) to control the growth of each set of protrusions, it is necessary to have an independent threshold regulator. Together, these experimentally-testable findings illustrate how our approach can be used to guide the design of regulatory circuits for achieving a desired target structure.

scholarly journals The regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Qiong Zhang ◽  
Lihu Wang ◽  
Zhongtang Wang ◽  
Rentang Zhang ◽  
Ping Liu ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candidate Genes ◽  
Lignin Content ◽  
Ectopic Expression ◽  
Lignin Biosynthesis ◽  
Cellulose Content ◽  
Nac Transcription Factors ◽  
Safranin O ◽  
Lignin Deposition ◽  
Lignin Biosynthetic Pathway

AbstractFruit lignification is due to lignin deposition in the cell wall during cell development. However, there are few studies on the regulation of cell wall lignification and lignin biosynthesis during fruit pigmentation. In this study, we investigated the regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube. The cellulose content decreased, while the lignin content increased in the winter jujube pericarp during pigmentation. Safranin O-fast green staining showed that the cellulose content was higher in the cell wall of winter jujube prior to pigmentation, whereas the lignin in the cell wall increased after pigmentation. The thickness of the epidermal cells decreased with pericarp pigmentation. A combined metabolomics and transcriptomics analysis showed that guaiacyl-syringyl (G-S) lignin was the main lignin type in the pericarp of winter jujube, and F5H (LOC107424406) and CCR (LOC107420974) were preliminarily identified as the key genes modulating lignin biosynthesis in winter jujube. Seventeen MYB and six NAC transcription factors (TFs) with potential regulation of lignin biosynthesis were screened out based on phylogenetic analysis. Three MYB and two NAC TFs were selected as candidate genes and further studied in detail. Arabidopsis ectopic expression and winter jujube pericarp injection of the candidate genes indicated that the MYB activator (LOC107425254) and the MYB repressor (LOC107415078) control lignin biosynthesis by regulating CCR and F5H, while the NAC (LOC107435239) TF promotes F5H expression and positively regulates lignin biosynthesis. These findings revealed the lignin biosynthetic pathway and associated genes during pigmentation of winter jujube pericarp and provide a basis for further research on lignin regulation.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Processing and Characterization of Recombinant von Willebrand Factor Expressed in Different Cell Types Using a Vaccinia Virus Vector

1992 ◽  
Vol 67 (01) ◽  
pp. 154-160 ◽  
Author(s):  
P Meulien ◽  
M Nishino ◽  
C Mazurier ◽  
K Dott ◽  
G Piétu ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Von Willebrand Factor ◽  
Human Fibroblasts ◽  
Active Form ◽  
Cell Types ◽  
Biologically Active ◽  
L Cells ◽  
Von Willebrand ◽  
Different Cell Types ◽  
Willebrand Factor

SummaryThe cloning of the cDNA encoding von Willebrand factor (vWF) has revealed that it is synthesized as a large precursor (pre-pro-vWF) molecule and it is now clear that the prosequence or vWAgll is responsible for the intracellular multimerization of vWF. We have cloned the complete vWF cDNA and expressed it using a recombinant vaccinia virus as vector. We have characterized the structure and function of the recombinant vWF (rvWF) secreted from five different cell types: baby hamster kidney (BHK), Chinese hamster ovary (CHO), human fibroblasts (143B), mouse fibroblasts (L) and primary embryonic chicken cells. Forty-eight hours after infection, the quantity of vWF antigen found in the cell supernatant varied from 3 to 12 U/dl depending on the cell type. By SDS-agarose gel electrophoresis, the percentage of high molecular weight forms of vWF varied from 39 to 49% relative to normal plasma for BHK, CHO, 143B and chicken cells but was less than 10% for L cells. In all cell types, the two anodic subbands of each multimer were missing. The two cathodic subbands were easily detected only in BHK and L cells. By SDS-PAGE of reduced samples, pro-vWF was present in similar quantity to the fully processed vWF subunit in L cells, present in moderate amounts in BHK and CHO and in very low amounts in 143B and chicken cells. rvWF from all cells bound to collagen and to platelets in the presence of ristocetin, the latter showing a high correlation between binding efficiency and degree of multimerization. rvWF from all cells was also shown to bind to purified FVIII and in this case binding appeared to be independent of the degree of multimerization. We conclude that whereas vWF is naturally synthesized only by endothelial cells and megakaryocytes, it can be expressed in a biologically active form from various other cell types.

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