An extensin peroxidase is associated with white-light inhibition of lupin (Lupinus albus) hypocotyl growth

1999 ◽  
Vol 26 (1) ◽  
pp. 29 ◽  
Author(s):  
P. Jackson ◽  
S. Paulo ◽  
C. P. P. Ricardo ◽  
M. Brownleader ◽  
P. O. Freire
Keyword(s):  
Cell Wall ◽  
White Light ◽  
Cell Expansion ◽  
Structural Changes ◽  
Lupinus Albus ◽  
Extension Rate ◽  
Hypocotyl Growth ◽  
Cross Links ◽  
Quantitative Changes

The spatial distribution of the major basic (B2; pI 8.8) peroxidase of the intercellular fluid has an inverse relation with extension rate in etiolated hypocotyls of Lupinus albus L., suggesting its possible role in the control of cell expansion. White-light irradiation of etiolated hypocotyls resulted in growth inhibition and the induction of B2 and acidic (A2, pI 4.7–5.2) isoperoxidases (EC 1.1.11.7) to higher physiological activities. However, only the activities of the B2 isoperoxidases underwent quantitative changes in both space and time which suggested their role in growth-retardation. We have purified the B2 and A2 (pI 5.2) peroxidases to apparent electrophoretic homogeneity. To corroborate evidence obtained elsewhere that growth cessation coincides with cell wall structural changes and cell wall rigidification, we have shown that the B2 peroxidase, and not A2 peroxidase, cross-links tomato extensin in vitro. The B2 peroxidase may therefore catalyse the developmentally and light regulated formation of a covalently cross-linked cell wall extensin matrix in lupin hypocotyls. The cell wall would be more rigid or more recalcitrant to wall-loosening and subsequently contribute to the control of cell expansion.

Cell Wall Permeability of Pinto Bean Cotyledon Cells Regulates In Vitro Fecal Fermentation and Gut Microbiota

2021 ◽  
Author(s):  
Yanrong Huang ◽  
Sushil Dhital ◽  
Feitong Liu ◽  
Xiong Fu ◽  
Qiang Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Changes ◽  
Microbiota Composition ◽  
Colonic Fermentation ◽  
Pinto Bean ◽  
Wall Permeability ◽  
Cell Wall Permeability ◽  
Cotyledon Cells ◽  
Whole Foods

Processing induced structural changes of whole foods on regulation of colonic fermentation rate and microbiota composition are least understood and often overlooked. In the present study, intact cotyledon cells from...

scholarly journals The Role of Brachypodium distachyon Wall-Associated Kinases (WAKs) in Cell Expansion and Stress Responses

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2478
Author(s):  
Xingwen Wu ◽  
Antony Bacic ◽  
Kim L. Johnson ◽  
John Humphries
Keyword(s):  
Cell Wall ◽  
Stress Response ◽  
Plant Cell ◽  
Stress Responses ◽  
Cell Expansion ◽  
Plant Cell Wall ◽  
Brachypodium Distachyon ◽  
Critical Role ◽  
Cell Integrity

The plant cell wall plays a critical role in signaling responses to environmental and developmental cues, acting as both the sensing interface and regulator of plant cell integrity. Wall-associated kinases (WAKs) are plant receptor-like kinases located at the wall—plasma membrane—cytoplasmic interface and implicated in cell wall integrity sensing. WAKs in Arabidopsis thaliana have been shown to bind pectins in different forms under various conditions, such as oligogalacturonides (OG)s in stress response, and native pectin during cell expansion. The mechanism(s) WAKs use for sensing in grasses, which contain relatively low amounts of pectin, remains unclear. WAK genes from the model monocot plant, Brachypodium distachyon were identified. Expression profiling during early seedling development and in response to sodium salicylate and salt treatment was undertaken to identify WAKs involved in cell expansion and response to external stimuli. The BdWAK2 gene displayed increased expression during cell expansion and stress response, in addition to playing a potential role in the hypersensitive response. In vitro binding assays with various forms of commercial polysaccharides (pectins, xylans, and mixed-linkage glucans) and wall-extracted fractions (pectic/hemicellulosic/cellulosic) from both Arabidopsis and Brachypodium leaf tissues provided new insights into the binding properties of BdWAK2 and other candidate BdWAKs in grasses. The BdWAKs displayed a specificity for the acidic pectins with similar binding characteristics to the AtWAKs.

scholarly journals Binding of eIF3 in complex with eIF5 and eIF1 to the 40S ribosomal subunit is accompanied by dramatic structural changes

2019 ◽  
Vol 47 (15) ◽  
pp. 8282-8300 ◽  
Author(s):  
Jakub Zeman ◽  
Yuzuru Itoh ◽  
Zdeněk Kukačka ◽  
Michal Rosůlek ◽  
Daniel Kavan ◽  
...  
Keyword(s):  
Structural Changes ◽  
Ribosomal Subunit ◽  
Initial Contact ◽  
40S Ribosomal Subunit ◽  
In Vitro Reconstitution ◽  
High Resolution Structure ◽  
Cross Links ◽  
Interaction Map ◽  
High Degree

Abstract eIF3 is a large multiprotein complex serving as an essential scaffold promoting binding of other eIFs to the 40S subunit, where it coordinates their actions during translation initiation. Perhaps due to a high degree of flexibility of multiple eIF3 subunits, a high-resolution structure of free eIF3 from any organism has never been solved. Employing genetics and biochemistry, we previously built a 2D interaction map of all five yeast eIF3 subunits. Here we further improved the previously reported in vitro reconstitution protocol of yeast eIF3, which we cross-linked and trypsin-digested to determine its overall shape in 3D by advanced mass-spectrometry. The obtained cross-links support our 2D subunit interaction map and reveal that eIF3 is tightly packed with its WD40 and RRM domains exposed. This contrasts with reported cryo-EM structures depicting eIF3 as a molecular embracer of the 40S subunit. Since the binding of eIF1 and eIF5 further fortified the compact architecture of eIF3, we suggest that its initial contact with the 40S solvent-exposed side makes eIF3 to open up and wrap around the 40S head with its extended arms. In addition, we mapped the position of eIF5 to the region below the P- and E-sites of the 40S subunit.

Partial disintegration of vegetable cell wall during cooking improves vitamin K1 (Phylloquinone) bioaccessibility in in vitro digestion

2021 ◽  
pp. 1-12
Author(s):  
Wichien Sriwichai ◽  
Myriam Collin ◽  
Sylvie Avallone
Keyword(s):  
Cell Wall ◽  
Structural Changes ◽  
Principal Component ◽  
In Vitro Digestion ◽  
Leafy Vegetables ◽  
Cell Wall Polysaccharide ◽  
Water Spinach ◽  
Brassica Alboglabra ◽  
Ipomoea Aquatic

Abstract. Vegetables rich in vitamin K consumption could prevent bleeding and maintain bone status. The aims of the present work were to investigate i) the effect of household cooking (i.e., boiling for 5 min at 100 °C in distilled water and stir-frying for 3 min at 180 °C in hot canola oil) on phylloquinone bioaccessibility of five rich phylloquinone leafy vegetables, namely Water spinach (Ipomoea aquatic Forssk), Amaranth (Amaranthus blitum subsp. oleraceus L.), Chinese broccoli (Brassica alboglabra), Pak choi (Brassica rapa L.) and Drumstick (Moringa oleifera Lam.), and ii) the structural changes of these leaves before and after in vitro gastro-intestinal digestion. All the experiments were realized in triplicate for each vegetable. The amounts of phylloquinone in leafy vegetables were noticeable in almost all species and ranged from 94 to 182 μg/100 g DM. Their cell wall polysaccharide contents greatly varied from 4.3 to 8.4 g for 100 g. The content in bioaccessible phylloquinone was low in raw leaves (<25 μg/100 g DM) as well as its bioaccessibility (<15%). Leaf pectin content impaired phylloquinone bioaccessibility using principal component analysis. Boiling and stir-frying significantly improved the bioaccessibility of phylloquinone in leaves by a factor of three to twelve and two to seven respectively (p<0.05). These variations were associated with changes in leaf structure. Palisade and spongy cells appeared ruptured and disorganized after stir-frying. Given the estimated bioaccessibility of phylloquinones, the consumption of 500 g of cooked wet leaves per day would cover phylloquinone needs of an individual adult average body weight.

Isolation of pectin-enriched products from red beet (Beta vulgaris L. var. conditiva) wastes: composition and functional properties

2011 ◽  
Vol 17 (6) ◽  
pp. 517-527 ◽  
Author(s):  
E.N. Fissore ◽  
N.M.A. Ponce ◽  
L. Matkovic ◽  
C.A. Stortz ◽  
A.M. Rojas ◽  
...  
Keyword(s):  
Cell Wall ◽  
Beta Vulgaris ◽  
Extraction Process ◽  
Physiological Effect ◽  
Cell Wall Polysaccharide ◽  
Citrate Buffer ◽  
Red Beet ◽  
Cross Links ◽  
By Products

The present work was dedicated to the development of an extraction process for red beet ( Beta vulgaris L. var. conditiva) by-products that preserves the high molecular weight of the macromolecules with the primary aim of waste upgrading. Our study concerns the extraction of pectin-enriched products with potential thickening properties for their usage in food formulation, as well as with some healthy physiological effect, by using citrate buffer (pH = 5.2) either alone or with enzymes (hemicellulase or cellulase) active on cell wall polysaccharide networks. Considering that red beet tissue contains ferulic acid, which cross-links pectin macromolecules through arabinose residues to anchor them into the cell wall, an alkaline pretreatment was also evaluated in order to perform polysaccharide hydrolysis in the cell wall network to accomplish higher renderings. Chemical composition and yield, as well as the in vitro glucose retention exerted by the isolated fiber products were finally analyzed.

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.

Electron microscopic study of the membrane glycoproteins in the rat kidney after cisplatin treatment

1989 ◽  
Vol 47 ◽  
pp. 912-913
Author(s):  
S.K. Aggarwal
Keyword(s):  
Alkaline Phosphatase ◽  
Rat Kidney ◽  
Light And Electron Microscopy ◽  
Kidney Tissue ◽  
Membrane Glycoproteins ◽  
Electron Microscopic ◽  
Before And After ◽  
Interstrand Cross Links ◽  
Cross Links

The proposed primary mechanism of action of the anticancer drug cisplatin (Cis-DDP) is through its interaction with DNA, mostly through DNA intrastrand cross-links or DNA interstrand cross-links. DNA repair mechanisms can circumvent this arrest thus permitting replication and transcription to proceed. Various membrane transport enzymes have also been demonstrated to be effected by cisplatin. Glycoprotein alkaline phosphatase was looked at in the proximal tubule cells before and after cisplatin both in vivo and in vitro for its inactivation or its removal from the membrane using light and electron microscopy.Outbred male Swiss Webster (Crl: (WI) BR) rats weighing 150-250g were given ip injections of cisplatin (7mg/kg). Animals were killed on day 3 and day 5. Thick slices (20-50.um) of kidney tissue from treated and untreated animals were fixed in 1% buffered glutaraldehyde and 1% formaldehyde (0.05 M cacodylate buffer, pH 7.3) for 30 min at 4°C. Alkaline phosphatase activity and carbohydrates were demonstrated according to methods described earlier.

In vitro assembly of 2-D crystals from partially purified EA1 protein secreted by Bacillus anthracis strain Delta Sterne-1

1994 ◽  
Vol 52 ◽  
pp. 276-277
Author(s):  
Mary Beth Downs ◽  
Wilson Ribot ◽  
Joseph W. Farchaus
Keyword(s):  
Cell Wall ◽  
Molecular Sieves ◽  
Cell Envelope ◽  
Single Species ◽  
Supporting Cell ◽  
Surface Layers ◽  
Rabbit Igg ◽  
In Vitro Assembly ◽  
Covalently Linked

Many bacteria possess surface layers (S-layers) that consist of a two-dimensional protein lattice external to the cell envelope. These S-layer arrays are usually composed of a single species of protein or glycoprotein and are not covalently linked to the underlying cell wall. When removed from the cell, S-layer proteins often reassemble into a lattice identical to that found on the cell, even without supporting cell wall fragments. S-layers exist at the interface between the cell and its environment and probably serve as molecular sieves that exclude destructive macromolecules while allowing passage of small nutrients and secreted proteins. Some S-layers are refractory to ingestion by macrophages and, generally, bacteria are more virulent when S-layers are present.When grown in rich medium under aerobic conditions, B. anthracis strain Delta Sterne-1 secretes large amounts of a proteinaceous extractable antigen 1 (EA1) into the growth medium. Immunocytochemistry with rabbit polyclonal anti-EAl antibody made against the secreted protein and gold-conjugated goat anti-rabbit IgG showed that EAI was localized at the cell surface (fig 1), which suggests its role as an S-layer protein.

Bacterial Peptidoglycan Stapling with Functionalized D-Amino Acids

2019 ◽  
Author(s):  
Sylvia L. Rivera ◽  
Akbar Espaillat ◽  
Arjun K. Aditham ◽  
Peyton Shieh ◽  
Chris Muriel-Mundo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Clinical Success ◽  
Bacterial Species ◽  
Enzymatic Reaction ◽  
Amino Acid Derivative ◽  
Wall Structure ◽  
Live Bacteria ◽  
Cross Links ◽  
Osmotic Lysis ◽  
Bacterial Peptidoglycan

Transpeptidation reinforces the structure of cell wall peptidoglycan, an extracellular heteropolymer that protects bacteria from osmotic lysis. The clinical success of transpeptidase-inhibiting β-lactam antibiotics illustrates the essentiality of these cross-linkages for cell wall integrity, but the presence of multiple, seemingly redundant transpeptidases in many bacterial species makes it challenging to determine cross-link function precisely. Here we present a technique to covalently link peptide strands by chemical rather than enzymatic reaction. We employ bio-compatible click chemistry to induce triazole formation between azido- and alkynyl-D-alanine residues that are metabolically installed in the cell walls of Gram-positive and Gram-negative bacteria. Synthetic triazole cross-links can be visualized by substituting azido-D-alanine with azidocoumarin-D-alanine, an amino acid derivative that undergoes fluorescent enhancement upon reaction with terminal alkynes. Cell wall stapling protects the model bacterium Escherichia coli from β-lactam treatment. Chemical control of cell wall structure in live bacteria can provide functional insights that are orthogonal to those obtained by genetics.<br>

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