scholarly journals Structure, organization, and functions of cellulose synthase complexes in higher plants

2007 ◽  
Vol 19 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Reginaldo A. Festucci-Buselli ◽  
Wagner C. Otoni ◽  
Chandrashekhar P. Joshi
Keyword(s):  
Cell Wall ◽  
Hydrogen Bonding ◽  
Plasma Membrane ◽  
Functional Organization ◽  
Higher Plants ◽  
Cellulose Synthase ◽  
Great Stability ◽  
Close Proximity ◽  
Cell Wall Polymers ◽  
Membrane Bound

Annually, plants produce about 180 billion tons of cellulose making it the largest reservoir of organic carbon on Earth. Cellulose is a linear homopolymer of beta(1-4)-linked glucose residues. The coordinated synthesis of glucose chains is orchestrated by specific plasma membrane-bound cellulose synthase complexes (CelS). The CelS is postulated to be composed of approximately 36 cellulose synthase (CESA) subunits. The CelS synthesizes 36 glucose chains in close proximity before they are further organized into microfibrils that are further associated with other cell wall polymers. The 36 glucose chains in a microfibril are stabilized by intra- and inter-hydrogen bonding which confer great stability on microfibrils. Several elementary microfibrils come together to form macrofibrils. Many CESA isoforms appear to be involved in the cellulose biosynthetic process and at least three types of CESA isoforms appear to be necessary for the functional organization of CelS in higher plants.

scholarly journals Effect of Exogenously Applied 24-Epibrassinolide and Brassinazole on Xylogenesis and Microdistribution of Cell Wall Polymers in Leucaena leucocephala (Lam) De Wit

2021 ◽  
Author(s):  
S. Pramod ◽  
M. Anju ◽  
H. Rajesh ◽  
A. Thulaseedharan ◽  
Karumanchi S. Rao
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Leucaena Leucocephala ◽  
Higher Plants ◽  
Lignin Content ◽  
Wood Quality ◽  
Wall Structure ◽  
Vessel Element ◽  
Xylem Differentiation ◽  
Cell Wall Polymers

AbstractPlant growth regulators play a key role in cell wall structure and chemistry of woody plants. Understanding of these regulatory signals is important in advanced research on wood quality improvement in trees. The present study is aimed to investigate the influence of exogenous application of 24-epibrassinolide (EBR) and brassinosteroid inhibitor, brassinazole (BRZ) on wood formation and spatial distribution of cell wall polymers in the xylem tissue of Leucaena leucocephala using light and immuno electron microscopy methods. Brassinazole caused a decrease in cambial activity, xylem differentiation, length and width of fibres, vessel element width and radial extent of xylem suggesting brassinosteroid inhibition has a concomitant impact on cell elongation, expansion and secondary wall deposition. Histochemical studies of 24-epibrassinolide treated plants showed an increase in syringyl lignin content in the xylem cell walls. Fluorescence microscopy and transmission electron microscopy studies revealed the inhomogenous pattern of lignin distribution in the cell corners and middle lamellae region of BRZ treated plants. Immunolocalization studies using LM10 and LM 11 antibodies have shown a drastic change in the micro-distribution pattern of less substituted and highly substituted xylans in the xylem fibres of plants treated with EBR and BRZ. In conclusion, present study demonstrates an important role of brassinosteroid in plant development through regulating xylogenesis and cell wall chemistry in higher plants.

Studies of the endoplasmic reticulum and plasma membrane-bound ribosomes in erythropoietic cells

1978 ◽  
Vol 31 (1) ◽  
pp. 165-178
Author(s):  
J.A. Grasso ◽  
A.L. Sullivan ◽  
S.C. Chan
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Exact Role ◽  
Whole Cells ◽  
Cytoplasmic Face ◽  
Close Proximity ◽  
Haem Biosynthesis ◽  
Hypotonic Buffer ◽  
Membrane Bound ◽  
Hypotonic Lysis

Erythropoietic cells of 5 species, including man, contain endoplasmic reticulum present as individual cisternae or tubules scattered throughout the cytoplasm of all stages except mature RBCs. The endoplasmic reticulum is mainly agranular but occurs frequently as a variant of granular ER which is characterized by an asymmetrical and irregular distribution of ribosomes along one cytoplasmic face. In most cells, the endoplasmic reticulum occurs in close proximity to mitochondria or the plasma membrane, suggesting that the organelle may be involved in functions related to these structures, e.g. haem biosynthesis. Endoplasmic reticulum is more abundant in early than in late erythroid cells. Its exact role in RBC development is unclear. Since endoplasmic reticulum could account for ‘plasma membrane-bound ribosomes’ reported in lysed reticulocytes, studies were performed which ruled out this possibility and which suggested that such ribosomes were an artifact of the lysing conditions. Hypotonic lysis in less than 20 vol. of magnesium-containing buffers yielded ghosts variably contaminated by ribosomes and other structures. Lysis of reticulocytes in 20–30 vol. of magnesium-free buffer or homogenization of whole cells or crude membrane fractions in hypotonic buffer removed virtually all contaminating ribosomes from the purified membrane fraction.

Lomasome biogenesis and function in armillaria mellea

1978 ◽  
Vol 36 (2) ◽  
pp. 402-403
Author(s):  
B. Ch. Behboodi
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Osmium Tetroxide ◽  
Higher Plants ◽  
Cell Wall Formation ◽  
Extensive Investigation ◽  
Sodium Cacodylate ◽  
Armillaria Mellea ◽  
Synthetic Media ◽  
And Function

IntroductionBorder bodies or lomasomes are the aggregation of membranes and vesicles located between the plasma membrane and the cell wall of many fungi, algae, and higher plants. Despite extensive investigation, the biogenesis as well as function of these structures is not yet known. The purpose of this investigation was to describe the biogenesis of lomasomes in Armillaria mellea and to provide some observations on their function related to cell wall formation.Materials and MethodsVarious thalli of fungi as non-aggregated hyphae, pseudosclerotes, rhizomorphs and carpophores were grown either on orange or synthetic media as described previously. The thalli were fixed in 4% glutaraldehyde buffered with 0.1 M sodium cacodylate (pH 7.4), and 0.15 M sucrose for 4 h at 4°. They were postfixed with 1% osmium tetroxide in the same buffer for 2 h at 4° and embedded in Epon according to the Luft procedure. Cytochemical studies using thiocarbohydrazide-silver proteinate were performed according the Thiéry.

scholarly journals Cellulose synthase complexes display distinct dynamic behaviors during xylem transdifferentiation

2018 ◽  
Vol 115 (27) ◽  
pp. E6366-E6374 ◽  
Author(s):  
Yoichiro Watanabe ◽  
Rene Schneider ◽  
Sarah Barkwill ◽  
Eliana Gonzales-Vigil ◽  
Joseph L. Hill ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Expansion ◽  
Secondary Wall ◽  
Transition Period ◽  
Cellulose Synthase ◽  
Wall Thickening ◽  
Cellulose Synthesis ◽  
Primary Wall ◽  
Dynamic Behaviors

In plants, plasma membrane-embedded CELLULOSE SYNTHASE (CESA) enzyme complexes deposit cellulose polymers into the developing cell wall. Cellulose synthesis requires two different sets of CESA complexes that are active during cell expansion and secondary cell wall thickening, respectively. Hence, developing xylem cells, which first undergo cell expansion and subsequently deposit thick secondary walls, need to completely reorganize their CESA complexes from primary wall- to secondary wall-specific CESAs. Using live-cell imaging, we analyzed the principles underlying this remodeling. At the onset of secondary wall synthesis, the primary wall CESAs ceased to be delivered to the plasma membrane and were gradually removed from both the plasma membrane and the Golgi. For a brief transition period, both primary wall- and secondary wall-specific CESAs coexisted in banded domains of the plasma membrane where secondary wall synthesis is concentrated. During this transition, primary and secondary wall CESAs displayed discrete dynamic behaviors and sensitivities to the inhibitor isoxaben. As secondary wall-specific CESAs were delivered and inserted into the plasma membrane, the primary wall CESAs became concentrated in prevacuolar compartments and lytic vacuoles. This adjustment in localization between the two CESAs was accompanied by concurrent decreased primary wall CESA and increased secondary wall CESA protein abundance. Our data reveal distinct and dynamic subcellular trafficking patterns that underpin the remodeling of the cellulose biosynthetic machinery, resulting in the removal and degradation of the primary wall CESA complex with concurrent production and recycling of the secondary wall CESAs.

A 67-kDa plasma-membrane-bound Ca 2+ -stimulated protein kinase active in sink tissue of higher plants

Planta ◽  
1998 ◽  
Vol 205 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Laurence D. P. Barker ◽  
Matthew D. Templeton ◽  
Ian B. Ferguson
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Higher Plants ◽  
Membrane Bound ◽  
Sink Tissue

The significance of cAMP induced alterations in the cellular structure of Phycomyces

1977 ◽  
Vol 23 (4) ◽  
pp. 378-388 ◽  
Author(s):  
J. C. Tu ◽  
S. K. Malhotra
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Chitin Synthesis ◽  
Phycomyces Blakesleeanus ◽  
Thin Sections ◽  
Tube Emergence ◽  
Membrane Bound ◽  
Time Required ◽  
Small Clusters ◽  
Different Levels

Effect of cyclic AMP (cAMP) on Phycomyces blakesleeanus was studied by growing sporangiospores on glucose–asparagine agar or liquid medium containing three different levels of cAMP (10, 20 and 40 μM) in addition to the control (no cAMP added). The response of Phycomyces to the exogenous cAMP concentration in the medium is as follows: (1) the time required for germ tube emergence is reduced; (2) the diameter of the mycelium is increased (sometimes more than 10 times) and frequency of branching is also increased; (3) the cell wall of the mycelium is thickened (in some cases more than 5 times); (4) the glycogen in the cytoplasm is decreased as visualized in thin sections and also demonstrated in biochemical quantitation; and (5) the distribution of intercalated membranous particles (Imp) on plasma membrane is altered and this can be easily detected in freeze-fractured replica. Such a change in Imp is seen in the formation of small clusters of aggregated particles on the plasmic half (PF) and craters on the complementary exoplasmic half(EF)of the plasma membrane. Although the mechanism of cAMP action requires further exploration, it is possible that the addition of cAMP to the culture medium leads to degradation of glycogen and enhancement of chitin synthesis since the cell wall is largely composed of chitin. The alteration in Imp may be related to a change in the activity of chitin synthetase which is a plasma membrane-bound enzyme.

scholarly journals A G protein-coupled receptor-like module regulates Cellulose Synthase secretion from the endomembrane system in Arabidopsis

2020 ◽  
Author(s):  
Heather E. McFarlane ◽  
Daniela Mutwil-Anderwald ◽  
Jana Verbančič ◽  
Kelsey L. Picard ◽  
Timothy E. Gookin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
G Protein ◽  
Protein Complex ◽  
Cellulose Synthase ◽  
Cell Wall Integrity ◽  
Cellulose Synthesis ◽  
Endomembrane System ◽  
G Protein Coupled

AbstractCellulose synthesis is essential for plant morphology, water transport and defense, and provides raw material for biomaterials and fuels. Cellulose is produced at the plasma membrane by Cellulose Synthase (CESA) protein complexes (CSCs). CSCs are assembled in the endomembrane system and then trafficked from the Golgi apparatus and trans-Golgi Network (TGN) to the plasma membrane. Since CESA enzymes are only active in the plasma membrane, control of CSC secretion is a critical step in the regulation of cellulose synthesis. However, the regulatory framework for CSC secretion is not clarified. In this study, we identify members of a family of seven transmembrane domain-containing proteins (7TMs) as important for cellulose production during cell wall integrity stress. 7TM proteins are often associated with guanine nucleotide-binding protein (G) protein signalling and mutants in several of the canonical G protein complex components phenocopied the 7tm mutant plants. Unexpectedly, the 7TM proteins localized to the Golgi apparatus/TGN where they interacted with the G protein complex. Here, the 7TMs and G proteins regulated CESA trafficking, but did not affect general protein secretion. Furthermore, during cell wall stress, 7TMs’ localization was biased towards small CESA-containing vesicles, specifically associated with CSC trafficking. Our results thus outline how a G protein-coupled module regulates CESA trafficking and reveal that defects in this process lead to exacerbated responses upon exposure to cell wall integrity stress.

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