scholarly journals Locating Methyl-Etherified and Methyl-Esterified Uronic Acids in the Plant Cell Wall Pectic Polysaccharide Rhamnogalacturonan II

2020 ◽  
Vol 25 (4) ◽  
pp. 329-344
Author(s):  
Malcolm A. O’Neill ◽  
Ian Black ◽  
Breeanna Urbanowicz ◽  
Vivek Bharadwaj ◽  
Mike Crowley ◽  
...  
Keyword(s):  
Plant Species ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Pectic Polysaccharide ◽  
Ionization Time ◽  
Methyl Esterification ◽  
Flight Mass Spectrometry ◽  
Borate Ester ◽  
Rhamnogalacturonan Ii

Rhamnogalacturonan II (RG-II) is a structurally complex pectic polysaccharide that exists as a borate ester cross-linked dimer in the cell walls of all vascular plants. The glycosyl sequence of RG-II is largely conserved, but there is evidence that galacturonic acid (GalA) methyl etherification and glucuronic acid (GlcA) methyl esterification vary in the A sidechain across plant species. Methyl esterification of the galacturonan backbone has also been reported but not confirmed. Here we describe a new procedure, utilizing aq. sodium borodeuteride (NaBD4)-reduced RG-II, to identify the methyl esterification status of backbone GalAs. Our data suggest that up to two different GalAs are esterified in the RG-II backbone. We also adapted a procedure based on methanolysis and NaBD4 reduction to identify 3-, 4-, and 3,4- O-methyl GalA in RG-II. These data, together with matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF) MS analysis of sidechain A generated from selected RG-IIs and their NaBD4-reduced counterparts, suggest that methyl etherification of the β-linked GalA and methyl esterification of the GlcA are widespread. Nevertheless, the extent of these modifications varies between plant species. Our analysis of the sidechain B glycoforms in RG-II from different dicots and nonpoalean monocots suggests that this sidechain has a minimum structure of an O-acetylated hexasaccharide (Ara-[MeFuc]-Gal-AceA-Rha-Api-). To complement these studies, we provide further evidence showing that dimer formation and stability in vitro is cation and borate dependent. Taken together, our data further refine the primary sequence and sequence variation of RG-II and provide additional insight into dimer stability and factors controlling dimer self-assembly.

Lead complexation in wines with the dimers of the grape pectic polysaccharide rhamnogalacturonan II

OENO One ◽  
1997 ◽  
Vol 31 (1) ◽  
pp. 33 ◽  
Author(s):  
Patrice Pellerin ◽  
Malcolm A. O'Neill ◽  
Cécile Pierre ◽  
Marie-Thérèse Cabanis ◽  
Alan G. Darvill ◽  
...  
Keyword(s):  
Plant Cell Wall ◽  
Red Wine ◽  
Lead Content ◽  
Size Exclusion ◽  
Human Diet ◽  
Pectic Polysaccharide ◽  
Rhamnogalacturonan Ii ◽  
Grape Varieties ◽  
Lead Complex

<p style="text-align: justify;">Wine is believed to be a significant source of lead in the human diet even though the lead content of wines has decreased considerably over the last thirty years. Nevertheless, the lead content of wines must be reduced to a minimum since this heavy metal is highly toxic.</p><p style="text-align: justify;">The plant cell wall pectic polysaccharide rhamnogalacturonan Il (RG-II) is a predominant anionic molecule in red wine. RG-Il exists as a dimer (dRG-Il-B) that is cross-linked by a 1:2 borate-diol ester and forms complexes <em>in vitro</em> with lead and other selected di- and tri-valent cations. One mole of dimer binds at least 1 mole of Pb<sup>2+</sup>. We have now determined the amount of lead in wines that is bound to dRG-II-B since previous studies have suggested that most of the lead in wine is bound to an anionic macromolecule.</p><p style="text-align: justify;">Seven wines, with lead concentrations between 30 and 110 μg/l, were obtained from different grape varieties harvested at different vintages and vinified by different procedures. Two chromatography steps, adsorption on a polystyrene- divinylbenzene resin and size-exclusion on a Superdex® 75-HR column, have been used to purify a d-RG-II-B-lead complex which contained at least 85 p. cent of the total lead of each wine. The dRG-II-B-Pb complex is stable at the pH of wine and is present in a wine that was procluced in 1988. The dRG-II-B present in red (~ 100 mg/l) and white (~ 20 mg/l) wines can bind at least ten-fold more Pb<sup>2+</sup> than is typically present in wine.</p><p style="text-align: justify;">Our study is the first to show that in wine most of the lead is complexed with a pectic polysaccharide that is not degraded during vinification. dRG-II-B is also known to form complexes with other cations, including strontium and barium. However, it is not known what role dRG-II-B has in determining the metabolic fate in humans of toxic cations present in wine.</p>

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.

O-glycans on human high endothelial CD34 putatively participating in L-selectin recognition

Blood ◽  
2002 ◽  
Vol 99 (7) ◽  
pp. 2609-2611 ◽  
Author(s):  
Tero Satomaa ◽  
Ossi Renkonen ◽  
Jari Helin ◽  
Juha Kirveskari ◽  
Antti Mäkitie ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Sialyl Lewis X ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Sialyl Lewis ◽  
Candidate Structure ◽  
Selectin Ligands ◽  
Matrix Assisted Laser

Leukocyte traffic into lymph nodes and sites of inflammation is guided by L-selectin. Experiments performed in vitro and with gene-deleted mice suggest that CD34 recognizes L-selectin if decorated by 6-sulfo sialyl Lewis x (sLex) saccharides and the MECA-79 epitope. However, very little is known about glycosylation of human L-selectin ligands. We report here on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiles of N- and O-linked oligosaccharide fractions from human tonsillar endothelial CD34. All detected O-glycans were sialylated; some were also monosulfated or monosulfated and monofucosylated. If a given CD34-glycan may carry all requirements for L-selectin recognition, that is, both 6-sulfo-sLex and MECA-79 epitopes, only one O-glycan fraction, O-9, SA2Hex3HexNAc3- Fuc1(SO3)1, meets the criteria. A candidate structure is SAα2-3Galβ1-4(Fucα1-3)(6-sulfo)GlcNAcβ1-3Galβ1-3(SAα2-3Galβ1-4GlcNAcβ1-6)GalNAc. However, if sulfo sLex glycans are supplemented with separate sulfated, nonfucosylated O-glycans, saccharides in O-6, O-8, or O-9, putatively carrying MECA-79 epitopes, could form multiglycan binding epitopes for L-selectin.

scholarly journals Oviduct Fluid Extracellular Vesicles Change the Phospholipid Composition of Bovine Embryos Developed In Vitro

2020 ◽  
Vol 21 (15) ◽  
pp. 5326 ◽  
Author(s):  
Charles Banliat ◽  
Daniel Le Bourhis ◽  
Ophélie Bernardi ◽  
Daniel Tomas ◽  
Valérie Labas ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Intact Cell ◽  
Phospholipid Composition ◽  
Cell Number ◽  
Phospholipid Content ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Before And After ◽  
Oviduct Fluid

Oviduct fluid extracellular vesicles (oEVs) have been proposed as bringing key molecules to the early developing embryo. In order to evaluate the changes induced by oEVs on embryo phospholipids, fresh bovine blastocysts developed in vitro in the presence or absence of oEVs were analyzed by intact cell MALDI-TOF (Matrix assisted laser desorption ionization—Time of flight) mass spectrometry (ICM-MS). The development rates, cryotolerance, and total cell number of blastocysts were also evaluated. The exposure to oEVs did not affect blastocyst yield or cryotolerance but modified the phospholipid content of blastocysts with specific changes before and after blastocoel expansion. The annotation of differential peaks due to oEV exposure evidenced a shift of embryo phospholipids toward more abundant phosphatidylcholines (PC), phosphatidylethanolamines (PE), and sphingomyelins (SM) with long-chain fatty acids. The lipidomic profiling of oEVs showed that 100% and 33% of the overabundant masses in blastocysts and expanded blastocysts, respectively, were also present in oEVs. In conclusion, this study provides the first analysis of the embryo lipidome regulated by oEVs. Exposure to oEVs induced significant changes in the phospholipid composition of resulting embryos, probably mediated by the incorporation of oEV-phospholipids into embryo membranes and by the modulation of the embryonic lipid metabolism by oEV molecular cargos.

scholarly journals Rhamnogalacturonan-II, a Pectic Polysaccharide in the Walls of Growing Plant Cell, Forms a Dimer That Is Covalently Cross-linked by a Borate Ester

1996 ◽  
Vol 271 (37) ◽  
pp. 22923-22930 ◽  
Author(s):  
Malcolm A. O'Neill ◽  
Dennis Warrenfeltz ◽  
Keith Kates ◽  
Patrice Pellerin ◽  
Thierry Doco ◽  
...  
Keyword(s):  
Plant Cell ◽  
Pectic Polysaccharide ◽  
Borate Ester ◽  
Rhamnogalacturonan Ii

scholarly journals Identification of a Protein That Inactivates the Competence-Stimulating Peptide of Streptococcus pneumoniae

2002 ◽  
Vol 184 (2) ◽  
pp. 610-613 ◽  
Author(s):  
Mathieu Bergé ◽  
Hanno Langen ◽  
Jean-Pierre Claverys ◽  
Bernard Martin
Keyword(s):  
Streptococcus Pneumoniae ◽  
Laser Desorption ◽  
Physiological Property ◽  
Laser Desorption Ionization ◽  
Treatment Results ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Licl Treatment

ABSTRACT Competence for genetic transformation of Streptococcus pneumoniae is a transient physiological property inducible by a competence-stimulating peptide (CSP). A 68-kDa CSP-inactivating protein was previously obtained following lithium chloride (LiCl) extraction. By the same protocol, a CSP-inactivating protein was purified and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry as an endopeptidase, PepO. Analysis of a pepO mutant provided no support for the hypothesis that PepO participates in competence regulation. To reconcile in vitro and in vivo data, we suggest that LiCl treatment results in the release of intracellular molecules, including PepO.

scholarly journals In Vitro Susceptibility of Fusarium to Isavuconazole

2019 ◽  
Vol 64 (2) ◽  
Author(s):  
A. Broutin ◽  
J. Bigot ◽  
Y. Senghor ◽  
A. Moreno-Sabater ◽  
J. Guitard ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
In Vitro Susceptibility ◽  
Ionization Time ◽  
Valuable Alternative ◽  
Flight Mass Spectrometry ◽  
Microdilution Method ◽  
Species Complexes ◽  
Broth Microdilution Method

ABSTRACT To evaluate the in vitro susceptibility of Fusarium to isavuconazole, 75 clinical isolates were identified using matrix-assisted laser desorption ionization–time of flight mass spectrometry and then tested with a broth microdilution method (EUCAST) and the gradient concentration strip (GCS) technique. The activity of isavuconazole overall was shown to be limited, with an MIC50 of >16 μg/ml, without significant differences between the species complexes. The categorical agreement between GCS and EUCAST was 97.4% to 100%, making the GCS as a valuable alternative.

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