scholarly journals Cell wall integrity signaling regulates cell wall regeneration via transcriptional activation in Chlamydomonas reinhardtii

2019 ◽  
Author(s):  
Evan Cronmiller ◽  
Deepak Toor ◽  
Nai Chun Shao ◽  
Thamali Kariyawasam ◽  
Ming Hsiu Wang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcriptional Activation ◽  
Cell Walls ◽  
De Novo ◽  
Intact Cell ◽  
Gene Activation ◽  
Cell Wall Integrity ◽  
Luciferase Reporter ◽  
Mrna Accumulation ◽  
Signaling Mechanisms

AbstractAn intact cell wall is critical for protecting the cell from osmotic challenges and harmful environments. Signaling mechanisms are necessary to monitor cell wall integrity and to regulate cell wall production and remodeling during growth and division cycles. The green alga, Chlamydomonas, has a proteinaceous cell wall of defined structure that is readily removed by gametolysin (g-lysin), a metalloprotease released during sexual mating. Naked cells treated with g-lysin induce the mRNA accumulation of > 100 cell wall-related genes within an hour, offering a system to study signaling and regulatory mechanisms for de novo cell wall assembly. Combining quantitative RT-PCR and luciferase reporter assays to probe transcript accumulation and promoter activity, we revealed that up to 500-fold upregulation of cell wall-related genes was driven at least partly by transcriptional activation upon g-lysin treatment. To investigate how naked cells trigger this rapid transcriptional activation, we tested whether osmotic stress and cell wall integrity are involved in this process. Under a constant hypotonic condition, comparable levels of cell wall-gene activation were observed by g-lysin treatment. In contrast, cells in an iso- or hypertonic condition showed up to 80% reduction in the g-lysin-induced gene activation, suggesting that hypotonic conditions are required for full-scale responses to g-lysin treatment. To test whether mechanical perturbation is involved, we isolated and examined a new set of cell wall mutants with defective or little cell walls. All cell wall mutants examined showed a constitutive upregulation of cell wall-related genes at the level, which would only be achieved by the g-lysin treatment in wild-type cells. Our study suggests a signaling that monitors mechanical defects of cell walls and regulates cell wall-gene expression in Chlamydomonas, which may relate to cell wall integrity signaling mechanisms in plants.

scholarly journals Even Visually Intact Cell Walls in Waterlogged Archaeological Wood Are Chemically Deteriorated and Mechanically Fragile: A Case of a 170 Year-Old Shipwreck

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1113 ◽  
Author(s):  
Liuyang Han ◽  
Xingling Tian ◽  
Tobias Keplinger ◽  
Haibin Zhou ◽  
Ren Li ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Intact Cell ◽  
Nitrogen Adsorption ◽  
Wet Chemistry ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood ◽  
X Ray Scattering ◽  
Crystallite Structure ◽  
Cell Wall Mechanics

Structural and chemical deterioration and its impact on cell wall mechanics were investigated for visually intact cell walls (VICWs) in waterlogged archaeological wood (WAW). Cell wall mechanical properties were examined by nanoindentation without prior embedding. WAW showed more than 25% decrease of both hardness and elastic modulus. Changes of cell wall composition, cellulose crystallite structure and porosity were investigated by ATR-FTIR imaging, Raman imaging, wet chemistry, 13C-solid state NMR, pyrolysis-GC/MS, wide angle X-ray scattering, and N2 nitrogen adsorption. VICWs in WAW possessed a cleavage of carboxyl in side chains of xylan, a serious loss of polysaccharides, and a partial breakage of β-O-4 interlinks in lignin. This was accompanied by a higher amount of mesopores in cell walls. Even VICWs in WAW were severely deteriorated at the nanoscale with impact on mechanics, which has strong implications for the conservation of archaeological shipwrecks.

Dysgenesis and dysfunction of pancreas and pituitary due to FOXA2 gene defects

2021 ◽  
Author(s):  
Sare Betul Kaygusuz ◽  
Esra Arslan Ates ◽  
Maria Lillina Vignola ◽  
Burcu Volkan ◽  
Bilgen Bilge Geckinli ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Developmental Disorders ◽  
De Novo ◽  
Luciferase Reporter ◽  
Forkhead Box ◽  
First Case ◽  
The Central Nervous System ◽  
Gene Defects ◽  
Congenital Hypopituitarism ◽  
Pancreatic Hypoplasia

Abstract Context Developmental disorders of the pituitary gland leading to congenital hypopituitarism can either be isolated or associated with extra-pituitary abnormalities (syndromic hypopituitarism). A large number of syndromic hypopituitarism cases are linked to mutations in transcription factors. The Forkhead box A2 (FOXA2) is a transcription factor that plays a key role in the central nervous system, foregut and pancreatic development. Objective To characterize two patients with syndromic hypopituitarism due to FOXA2 gene defects. Results We report a novel heterozygous nonsense c.616C>T (p.Q206X) variant, which leads to a truncated protein that lacks part of the DNA-binding domain of FOXA2, resulting in impaired transcriptional activation of the GLUT2-luciferase reporter. The patient is the sixth patient described in the literature with a FOXA2 mutation, and the first patient exhibiting pancreatic hypoplasia. We also report a second patient with a novel de novo 8.53 megabase (Mb) deletion of 20p11.2 that encompasses FOXA2, who developed diabetes mellitus that responded to sulfonylurea treatment. Conclusions Our two cases broaden the molecular and clinical spectrum of FOXA2-related disease, reporting the first nonsense mutation and the first case of pancreatic dysgenesis.

scholarly journals Cell fusion in yeast is negatively regulated by components of the cell wall integrity pathway

2019 ◽  
Vol 30 (4) ◽  
pp. 441-452 ◽  
Author(s):  
Allison E. Hall ◽  
Mark D. Rose
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Death ◽  
Cell Wall ◽  
Yeast Cell ◽  
Cell Fusion ◽  
Cell Walls ◽  
Cell Wall Integrity ◽  
Fusion Genes ◽  
Cell Wall Degradation ◽  
Cell Wall Integrity Pathway

During mating, Saccharomyces cerevisiae cells must degrade the intervening cell wall to allow fusion of the partners. Because improper timing or location of cell wall degradation would cause lysis, the initiation of cell fusion must be highly regulated. Here, we find that yeast cell fusion is negatively regulated by components of the cell wall integrity (CWI) pathway. Loss of the cell wall sensor, MID2, specifically causes “mating-induced death” after pheromone exposure. Mating-induced death is suppressed by mutations in cell fusion genes ( FUS1, FUS2, RVS161, CDC42), implying that mid2Δ cells die from premature fusion without a partner. Consistent with premature fusion, mid2Δ shmoos had thinner cell walls and lysed at the shmoo tip. Normally, Cdc42p colocalizes with Fus2p to form a focus only when mating cells are in contact (prezygotes) and colocalization is required for cell fusion. However, Cdc42p was aberrantly colocalized with Fus2p to form a focus in mid2Δ shmoos. A hyperactive allele of the CWI kinase Pkc1p ( PKC1*) caused decreased cell fusion and Cdc42p localization in prezygotes. In shmoos, PKC1* increased Cdc42p localization; however, it was not colocalized with Fus2p or associated with cell death. We conclude that Mid2p and Pkc1p negatively regulate cell fusion via Cdc42p and Fus2p.

A SEROLOGICAL STUDY OF CELL WALLS OF CERTAIN LACTIC ACID BACTERIA

1962 ◽  
Vol 8 (5) ◽  
pp. 629-637
Author(s):  
K. L. Chung ◽  
Roma Z. Hawirko
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Intact Cell ◽  
Synthetic Medium ◽  
Specific Cell ◽  
Intact Cells ◽  
Common Antigens ◽  
Species Specific ◽  
Relationship Of ◽  
The Relationship

From three species of Lactobacillus and three species of Streptococcus, cultured in a synthetic medium, cell walls were isolated following sonic disintegration and purified by washing. Sera against each species were prepared by injecting three rabbits with cell walls, and three with intact cells. Reciprocal agglutination tests were carried out with unabsorbed and absorbed antisera. More kinds of antibodies were detected with cell-wall antisera than with intact-cell antisera. Many species in the two genera shared common antigens. S. faecalis was the exception. Certain antigens believed to be complex haptens in nature reacted with heterologous antisera. Haemagglutination of tanned erythrocytes sensitized with a particulate cell-wall suspension showed fewer cross reactions than agglutination of intact-cell suspensions.The evidence presented shows the possibility of using antisera against species-specific cell-wall antigens for the identification of these species. The relationship of these species is discussed.

Differences in endosperm cell wall integrity in wheat (Triticum aestivum L.) milling fractions impact on the way starch responds to gelatinization and pasting treatments and its subsequent enzymatic in vitro digestibility

2019 ◽  
Vol 10 (8) ◽  
pp. 4674-4684 ◽  
Author(s):  
Konstantinos Korompokis ◽  
Niels De Brier ◽  
Jan A. Delcour
Keyword(s):  
Triticum Aestivum ◽  
Cell Wall ◽  
Cell Walls ◽  
Triticum Aestivum L ◽  
Cell Wall Integrity ◽  
In Vitro Digestibility ◽  
Endosperm Cell ◽  
Amylolytic Enzymes ◽  
Physical Barriers

Intact wheat endosperm cell walls reduce intracellular starch swelling and retard its in vitro digestion by acting as physical barriers to amylolytic enzymes.

scholarly journals The Role of Mechanoperception in Plant Cell Wall Integrity Maintenance

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 574 ◽  
Author(s):  
Laura Bacete ◽  
Thorsten Hamann
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Molecular Mechanisms ◽  
Plant Cell Wall ◽  
Cell Wall Integrity ◽  
Adaptive Changes ◽  
Structural Support ◽  
Dynamic Structures ◽  
Molecular Components

The plant cell walls surrounding all plant cells are highly dynamic structures, which change their composition and organization in response to chemical and physical stimuli originating both in the environment and in plants themselves. They are intricately involved in all interactions between plants and their environment while also providing adaptive structural support during plant growth and development. A key mechanism contributing to these adaptive changes is the cell wall integrity (CWI) maintenance mechanism. It monitors and maintains the functional integrity of cell walls by initiating adaptive changes in cellular and cell wall metabolism. Despite its importance, both our understanding of its mode of action and knowledge regarding the molecular components that form it are limited. Intriguingly, the available evidence implicates mechanosensing in the mechanism. Here, we provide an overview of the knowledge available regarding the molecular mechanisms involved in and discuss how mechanoperception and signal transduction may contribute to plant CWI maintenance.

scholarly journals Ethanolamine Utilization Contributes to Proliferation ofSalmonella entericaSerovar Typhimurium in Food and in Nematodes

2010 ◽  
Vol 77 (1) ◽  
pp. 281-290 ◽  
Author(s):  
Shabarinath Srikumar ◽  
Thilo M. Fuchs
Keyword(s):  
Salmonella Enterica ◽  
De Novo ◽  
Bacterial Species ◽  
Gene Activation ◽  
Carbon Sources ◽  
Egg Yolk ◽  
Gene Clusters ◽  
Luciferase Reporter ◽  
Infection Model ◽  
Reporter System

ABSTRACTOnly three pathogenic bacterial species,Salmonella enterica,Clostridium perfringens, andListeria monocytogenes, are able to utilize both ethanolamine and 1,2-propanediol as a sole carbon source. Degradation of these substrates, abundant in food and the gut, depends on cobalamin, which is synthesizedde novoonly under anaerobic conditions. Although theeut,pdu, andcob-cbigene clusters comprise 40 kb, the conditions under which they confer a selection advantage on these food-borne pathogens remain largely unknown. Here we used the luciferase reporter system to determine the response of theSalmonella entericaserovar Typhimurium promoters PeutS, PpocR, PpduF, and PpduAto a set of carbon sources, to egg yolk, to whole milk, and to milk protein or fat fractions. Depending on the supplements, specific inductions up to 3 orders of magnitude were observed for PeutSand PpduA, which drive the expression of mosteutandpdugenes. To correlate these significant expression data with growth properties, nonpolar deletions ofpocR, regulating thepduandcob-cbigenes, and ofeutR, involved ineutgene activation, were constructed inS. Typhimurium strain 14028. During exponential growth of the mutants 14028ΔpocRand 14028ΔeutR, 2- to 3-fold-reduced proliferation in milk and egg yolk was observed. Using theCaenorhabditis elegansinfection model, we could also demonstrate that the proliferation ofS. Typhimurium in the nematode is supported by an active ethanolamine degradation pathway. Taking these findings together, this study quantifies the differential expression ofeutandpdugenes under distinct conditions and provides experimental evidence that the ethanolamine utilization pathway allows salmonellae to occupy specific metabolic niches within food environments and within their host organisms.

scholarly journals Yeast Mpk1 Cell Wall Integrity Mitogen-activated Protein Kinase Regulates Nucleocytoplasmic Shuttling of the Swi6 Transcriptional Regulator

2010 ◽  
Vol 21 (9) ◽  
pp. 1609-1619 ◽  
Author(s):  
Ki-Young Kim ◽  
Andrew W. Truman ◽  
Stefanie Caesar ◽  
Gabriel Schlenstedt ◽  
David E. Levin
Keyword(s):  
Cell Wall ◽  
Protein Kinase ◽  
Transcriptional Activation ◽  
Transcriptional Response ◽  
Wall Stress ◽  
Cell Wall Integrity ◽  
Mitogen Activated Protein Kinase ◽  
Nucleocytoplasmic Shuttling ◽  
Nuclear Entry ◽  
Mitogen Activated Protein

The yeast SBF transcription factor is a heterodimer comprised of Swi4 and Swi6 that has a well defined role in cell cycle-specific transcription. SBF serves a second function in the transcriptional response to cell wall stress in which activated Mpk1 mitogen-activated protein kinase of the cell wall integrity signaling pathway forms a complex with Swi4, the DNA binding subunit of SBF, conferring upon Swi4 the ability to bind DNA and activate transcription of FKS2. Although Mpk1–Swi4 complex formation and transcriptional activation of FKS2 does not require Mpk1 catalytic activity, Swi6 is phosphorylated by Mpk1 and must be present in the Mpk1-Swi4 complex for transcriptional activation of FKS2. Here, we find that Mpk1 regulates Swi6 nucleocytoplasmic shuttling in a biphasic manner. First, formation of the Mpk1-Swi4 complex recruits Swi6 to the nucleus for transcriptional activation. Second, Mpk1 negatively regulates Swi6 by phosphorylation on Ser238, which inhibits nuclear entry. Ser238 neighbors a nuclear localization signal (NLS) whose function is blocked by phosphorylation at Ser238 in a manner similar to the regulation by Cdc28 of another Swi6 NLS, revealing a mechanism for the integration of multiple signals to a single endpoint. Finally, the Kap120 β-importin binds the Mpk1-regulated Swi6 NLS but not the Cdc28-regulated NLS.

scholarly journals The role of plant cell wall encapsulation and porosity in regulating lipolysis during the digestion of almond seeds

2016 ◽  
Vol 7 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Myriam M. L. Grundy ◽  
Frédéric Carrière ◽  
Alan R. Mackie ◽  
David A. Gray ◽  
Peter J. Butterworth ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Intact Cell ◽  
Lipid Digestion

Intact cell walls of almond prevent lipase penetration thus hindering lipid digestion.

scholarly journals Transcriptional activation of the human cytotoxic serine protease gene CSP-B in T lymphocytes.

1990 ◽  
Vol 10 (11) ◽  
pp. 5655-5662 ◽  
Author(s):  
R D Hanson ◽  
T J Ley
Keyword(s):  
T Cell ◽  
Serine Protease ◽  
Transcriptional Activation ◽  
Cytotoxic T Lymphocyte ◽  
Gene Activation ◽  
Dnase I ◽  
Protease Gene ◽  
Flanking Sequence ◽  
Mrna Accumulation ◽  
Gamma Delta T Cell

The cytotoxic serine protease B (CSP-B) gene is activated during cytotoxic T-lymphocyte maturation. In this report, we demonstrate that the PEER T-cell line (bearing gamma/delta T-cell receptors) accumulates CSP-B mRNA following exposure to 12-O-tetradecanoylphorbol-13-acetate (TPA) and N6-2'-O-dibutyryladenosine 3',5'-cyclic monophosphate (bt2cAMP) because of transcriptional activation of the CSP-B gene. TPA and bt2cAMP act synergistically to induce CSP-B expression, since neither agent alone causes activation of CSP-B transcription or mRNA accumulation. Chromatin upstream from the CSP-B gene is resistant to DNase I digestion in untreated PEER cells, but becomes sensitive following TPA-bt2cAMP treatment. Upon activation of PEER cells, a DNase I-hypersensitive site forms upstream from the CSP-B gene within a region that is highly conserved in the mouse. Transient transfection of CSP-B promoter constructs identified two regulatory regions in the CSP-B 5'-flanking sequence, located at positions -609 to -202 and positions -202 to -80. The region from -615 to -63 is sufficient to activate a heterologous promoter in activated PEER cells, but activation is orientation specific, suggesting that this region behaves as an upstream promoter element rather than a classical enhancer. Consensus AP-1, AP-2, and cAMP response elements are found upstream from the CSP-B gene (as are several T-cell-specific consensus elements), but the roles of these elements in CSP-B gene activation have yet to be determined.

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