scholarly journals CASP microdomain formation requires cross cell wall stabilization of domains between neighbors and non-cell autonomous action of LOTR1 cell wall protein

2020 ◽  
Author(s):  
Andreas Kolbeck ◽  
Peter Marhavý ◽  
Damien De Bellis ◽  
Lothar Kalmbach ◽  
Niko Geldner
Keyword(s):  
Cell Wall ◽  
Three Dimensional ◽  
Dominant Negative ◽  
Membrane Domains ◽  
Autonomous Action ◽  
Autonomous Pathway ◽  
Casparian Strip ◽  
Efficient Uptake ◽  
Uptake Of Nutrients ◽  
Negative Phenotype

SummaryEfficient uptake of nutrients in both animal and plant cells requires tissue-spanning diffusion barriers separating inner tissues from the outer lumen/soil. However, we poorly understand how these contiguous three-dimensional superstructures are formed in plants. Here, we show that correct establishment of the plant Casparian Strip (CS) network requires neighbor communication. We show that positioning of Casparian Strip membrane domains (CSDs) is tightly coordinated between neighbors in wild-type and that restriction of domain formation involves the putative extracellular protease LOTR1. Impaired domain restriction in lotr1 is associated with disrupted CSDs and establishment of fully functional CSD at ectopic positions, forming “half strips”. LOTR1 is expressed in stele and needs to be expressed there. Endodermal expression, by contrast, cannot complement, while cortex expression causes a dominant-negative phenotype. Our findings establish LOTR1 as a crucial player in CSD positioning acting in a non-cell-autonomous pathway to restrict and coordinate CS positioning.

scholarly journals CASP microdomain formation requires cross cell wall stabilization of domains and non-cell autonomous action of LOTR1

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Andreas Kolbeck ◽  
Peter Marhavý ◽  
Damien De Bellis ◽  
Baohai Li ◽  
Takehiro Kamiya ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dominant Negative ◽  
Membrane Domains ◽  
Domain Formation ◽  
Wild Type ◽  
Autonomous Action ◽  
Casparian Strip ◽  
Efficient Uptake ◽  
Uptake Of Nutrients ◽  
Negative Phenotype

Efficient uptake of nutrients in both animal and plant cells requires tissue-spanning diffusion barriers separating inner tissues from the outer lumen/soil. However, we poorly understand how such contiguous three-dimensional superstructures are formed in plants. Here, we show that correct establishment of the plant Casparian Strip (CS) network relies on local neighbor communication. We show that positioning of Casparian Strip membrane domains (CSDs) is tightly coordinated between neighbors in wild-type and that restriction of domain formation involves the putative extracellular protease LOTR1. Impaired domain restriction in lotr1 leads to fully functional CSDs at ectopic positions, forming 'half strips'. LOTR1 action in the endodermis requires its expression in the stele. LOTR1 endodermal expression cannot complement, while cortex expression causes a dominant-negative phenotype. Our findings establish LOTR1 as a crucial player in CSD positioning acting in a directional, non-cell-autonomous manner to restrict and coordinate CS positioning.

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

scholarly journals Pak1 regulates branching morphogenesis in 3D MDCK cell culture by a PIX and β1-integrin-dependent mechanism

2010 ◽  
Vol 299 (1) ◽  
pp. C21-C32 ◽  
Author(s):  
Michael P. Hunter ◽  
Mirjam M. Zegers
Keyword(s):  
Cell Culture ◽  
Mdck Cell ◽  
Three Dimensional ◽  
3D Culture ◽  
Branching Morphogenesis ◽  
Dominant Negative ◽  
Β1 Integrin ◽  
Blocking Antibody ◽  
Important Regulator ◽  
P21 Activated Kinase

Branching morphogenesis is a fundamental process in the development of the kidney. This process gives rise to a network of ducts, which form the collecting system. Defective branching can lead to a multitude of kidney disorders including agenesis and reduced nephron number. The formation of branching tubules involves changes in cell shape, cell motility, and reorganization of the cytoskeleton. However, the exact intracellular mechanisms involved are far from understood. We have used the three-dimensional (3D) Madin-Darby canine kidney (MDCK) cell culture system to study how p21-activated kinase 1 (Pak1), which is an important regulator of the cytoskeleton, modulates branching. Our data reveal that Pak1 plays a crucial role in regulating branching morphogenesis. Expression of a dominant-negative Pak1 mutant (DN-Pak1) in MDCK cysts resulted in the spontaneous formation of extensions and branching tubules. Cellular contractility and levels of phosphorylated myosin light chain (pMLC) were increased in DN-Pak1 cells in collagen. Expression of a DN-Pak1 mutant that does not bind to PIX (DN-Pak1-ΔPIX) failed to form extensions in collagen and did not have increased contractility. This shows that the DN-Pak1 mutant requires PIX binding to generate extensions and increased contractility in 3D culture. Furthermore, a β1-integrin function-blocking antibody (AIIB2) inhibited the formation of branches and blocked the increased contractility in DN-Pak1 cysts. Taken together, our work shows that DN-Pak1-induced branching morphogenesis requires PIX binding and β1-integrin signaling.

scholarly journals Serial Block-Face Scanning Electron Microscopy Reveals That Intercellular Nuclear Migration Occurs in Most Normal Tobacco Male Meiocytes

2021 ◽  
Vol 12 ◽  
Author(s):  
Sergey Mursalimov ◽  
Nobuhiko Ohno ◽  
Mami Matsumoto ◽  
Sergey Bayborodin ◽  
Elena Deineko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Three Dimensional ◽  
Nuclear Migration ◽  
Male Meiosis ◽  
Face Scanning ◽  
Block Face ◽  
Plant Meiosis ◽  
Scanning Electron

Serial block-face scanning electron microscopy (SBF-SEM) was used here to study tobacco male meiosis. Three-dimensional ultrastructural analyses revealed that intercellular nuclear migration (INM) occurs in 90–100% of tobacco meiocytes. At the very beginning of meiosis, every meiocyte connected with neighboring cells by more than 100 channels was capable of INM. At leptotene and zygotene, the nucleus in most tobacco meiocytes approached the cell wall and formed nuclear protuberances (NPs) that crossed the cell wall through the channels and extended into the cytoplasm of a neighboring cell. The separation of NPs from the migrating nuclei and micronuclei formation were not observed. In some cases, the NPs and nuclei of neighboring cells appeared apposed to each other, and the gap between their nuclear membranes became invisible. At pachytene, NPs retracted into their own cells. After that, the INM stopped. We consider INM a normal part of tobacco meiosis, but the reason for such behavior of nuclei is unclear. The results obtained by SBF-SEM suggest that there are still many unexplored features of plant meiosis hidden by limitations of common types of microscopy and that SBF-SEM can turn over a new leaf in plant meiosis research.

scholarly journals Pteridium Aquilinum (L.) Kuhn (Bracken) As an Invasive Species in Permanent Grassland Ecosystems - Possibilities and Methods of Control

2011 ◽  
Vol 68 (1) ◽  
Author(s):  
Dorin PLESA ◽  
Gheorghe MIHAI ◽  
Nicuşor SIMA ◽  
Dan PAVEL ◽  
Mihaela MIHAI ◽  
...  
Keyword(s):  
Pteridium Aquilinum ◽  
Good Reduction ◽  
Grassland Ecosystems ◽  
Mechanical Methods ◽  
Wide Range ◽  
The World ◽  
Efficient Uptake ◽  
Uptake Of Nutrients ◽  
Spring Sowing ◽  
Methods Of Control

. Pteridium species around the world are aggressive, very productive, functionally closer to shrubs than ferns. Their rhizomes, buried deep and rich in starch, allow them to survive repeated fires and their efficient uptake of nutrients allow them to exploit a wide range of soils (McGlone et al., 2005). Mechanical methods. Tillage and cultivation. On lands that are not too steep or rocky, a good reduction in fern coverage can be achieved by plowing from late June to early August. The goal is to plow deep in order to expose the rhizomes, leaving them undisturbed throughout the winter and followed by the spring sowing

scholarly journals Cryo-Electron Tomography Reveals the Comparative Three-Dimensional Architecture of Prochlorococcus, a Globally Important Marine Cyanobacterium

2007 ◽  
Vol 189 (12) ◽  
pp. 4485-4493 ◽  
Author(s):  
Claire S. Ting ◽  
Chyongere Hsieh ◽  
Sesh Sundararaman ◽  
Carmen Mannella ◽  
Michael Marko
Keyword(s):  
Cell Wall ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Membrane System ◽  
Niche Differentiation ◽  
Dimensional Structure ◽  
Comparative Genomic ◽  
Photosynthetic Membrane ◽  
Peptidoglycan Biosynthesis ◽  
Cryo Electron Tomography

ABSTRACT In an age of comparative microbial genomics, knowledge of the near-native architecture of microorganisms is essential for achieving an integrative understanding of physiology and function. We characterized and compared the three-dimensional architecture of the ecologically important cyanobacterium Prochlorococcus in a near-native state using cryo-electron tomography and found that closely related strains have diverged substantially in cellular organization and structure. By visualizing native, hydrated structures within cells, we discovered that the MED4 strain, which possesses one of the smallest genomes (1.66 Mbp) of any known photosynthetic organism, has evolved a comparatively streamlined cellular architecture. This strain possesses a smaller cell volume, an attenuated cell wall, and less extensive intracytoplasmic (photosynthetic) membrane system compared to the more deeply branched MIT9313 strain. Comparative genomic analyses indicate that differences have evolved in key structural genes, including those encoding enzymes involved in cell wall peptidoglycan biosynthesis. Although both strains possess carboxysomes that are polygonal and cluster in the central cytoplasm, the carboxysomes of MED4 are smaller. A streamlined cellular structure could be advantageous to microorganisms thriving in the low-nutrient conditions characteristic of large regions of the open ocean and thus have consequences for ecological niche differentiation. Through cryo-electron tomography we visualized, for the first time, the three-dimensional structure of the extensive network of photosynthetic lamellae within Prochlorococcus and the potential pathways for intracellular and intermembrane movement of molecules. Comparative information on the near-native structure of microorganisms is an important and necessary component of exploring microbial diversity and understanding its consequences for function and ecology.

scholarly journals Three-dimensional structure of the bacterial cell wall peptidoglycan

2006 ◽  
Vol 103 (12) ◽  
pp. 4404-4409 ◽  
Author(s):  
S. O. Meroueh ◽  
K. Z. Bencze ◽  
D. Hesek ◽  
M. Lee ◽  
J. F. Fisher ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Three Dimensional ◽  
Bacterial Cell Wall ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Cell Wall Peptidoglycan

Localisation of the Schizosaccharomyces pombe rho1p GTPase and its involvement in the organisation of the actin cytoskeleton

1997 ◽  
Vol 110 (20) ◽  
pp. 2547-2555 ◽  
Author(s):  
M. Arellano ◽  
A. Duran ◽  
P. Perez
Keyword(s):  
Cell Wall ◽  
Actin Cytoskeleton ◽  
Schizosaccharomyces Pombe ◽  
Antifungal Drugs ◽  
Dominant Negative ◽  
Cortical Actin ◽  
Glucan Synthase ◽  
Cell Wall Growth ◽  
Wall Growth ◽  
Mutant Cells

The Schizosaccharomyces pombe rho1p GTPase directly activates the (1–3) beta-D-glucan synthase and participates in the regulation of cell wall growth and morphogenesis in this fission yeast. Indirect immunofluorescence experiments using rho1p tagged with hemagglutinin have revealed that rho1p was located at the growing tips during interphase and at the septum prior to cytokinesis, localising to the same areas as actin patches. In S. pombe cdc10-129 mutant cells, arrested in G1, HA-rho1p accumulates at one tip whereas in cdc25-22 mutants, arrested in G2, HA-rho1p accumulates at both tips. In tea1-1 and tea2-1 cdc11-119 mutant cells, HA-rho1p is localised to the new growing tips. Overexpression of different rho1 mutant alleles caused different effects on cortical actin patch distribution, (1–3) beta-D-glucan synthase activation, and sensitivity to cell wall specific antifungal drugs. These results indicate that multiple cellular components are activated by rho1p. Overexpression of the dominant negative rho1T20N allele was lethal as was the rho1+ deletion. Moreover, when rho1+ expression was repressed in actively growing S. pombe, cells died in about 10 to 12 hours. Under these conditions, normal cell morphology was maintained but the level of (1–3) beta-D-glucan synthase activity decreased and the actin patches disappeared. Most cells lysed after cytokinesis during the process of separation, and lysis was not prevented by an osmotic stabiliser. We conclude that rho1p localisation is restricted to growth areas and regulated during the cell cycle and that rho1p is involved in cell wall growth and actin cytoskeleton organisation in S. pombe.

METHODS FOR INDICATION OF NONCULTURATED VIABLE MICROORGANISMS WHEN CONTROL OF CRITICAL POINTS OF LIVESTOCK, POULTRY AND FOOD PRODUCTION TECHNOLOGY

2021 ◽  
Vol 1 (4) ◽  
pp. 441-447
Author(s):  
Ekaterina M. Lenchenko ◽  
◽  
Damir I. Udavliev ◽  
Inna B. Pavlova ◽  
◽  
...  
Keyword(s):  
Cell Wall ◽  
Luminescence Spectrum ◽  
Three Dimensional ◽  
Yeast Cells ◽  
Dimensional Structure ◽  
Heterogeneous Structure ◽  
Bacterial Cells ◽  
Microscopic Fungi ◽  
Gram Positive Bacteria ◽  
Red Luminescence

The results of morphometric and densitometric parameters biofilms are presented, effective methods of detecting uncultivated viable microorganisms isolated from a representative sample of objects of veterinary and sanitary supervision are tested and selected. Optical, luminescent and scanning electron microscopy revealed the formation of a three-dimensional structure biofilms in the form a dense network consisting of gram-negative and gram-positive bacteria, yeast cells, hyphal and pseudohyphalic forms, surrounded by an intercellular polymer matrix. The presence hyphae of microscopic fungi causes an increase in the number of cells adhered to the substrate, microcolonies were formed from bacteria and yeast cells of microscopic fungi. The pathogenesis of the syndrome of overgrowth of microorganisms is provided by the presence of various dissociative variants, the dispersion of uncultivated bacterial cells, which gain advantages in the hyperagregation of the architectonics of heterogeneous biofilms. Multilayer membranes, vesicles, cells with a defective cell wall, spheroplasts, protoplasts, L-shapes, needle-like and giant structures, and revertant cells were identified. The dynamics of changes in the viable structures microorganisms was characterized by alternating periods of decrease and increase in the intensity of biofilm formation. When detecting the viability of microorganisms in the composition biofilms, viable and non-viable cells were differentiated – a green luminescence spectrum and a red luminescence spectrum, respectively. The dissociation of the population caused an increase in the concentration of R-dissociant cells with a higher growth rate, cell lysis was detected after 48–72 h of cultivation, a change in the ratio phenotypic forms was observed – the M-dissociant was predominant. The study of the heterogeneous structure of the population, without disturbing the natural architectonics of biofilms, revealed direct correlations (r = 0,89) between morphometric (≥90 % of the field of view) and densitometric parameters (OD). The efficiency of a nutrient medium containing pancreatic hydrolyzate, mannitol, L-asparagine and glycerol was established for the repair of the cell wall, the reversal of L-forms of microorganisms.

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