scholarly journals Investigations of the cell-wall substances of plants, with special reference to the chemical changes taking place during lignification

1928 ◽  
Vol 103 (725) ◽  
pp. 365-376 ◽  
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Special Reference ◽  
High Molecular Weight ◽  
Cell Walls ◽  
Chemical Entity ◽  
Chemical Changes ◽  
Group Iii ◽  
Woody Tissues

As the result of various investigations, to which, reference will be given in the text of this communication, it is possible to divide the substances which accompany cellulose in the cell-walls of plants among this following groups:— (i) The lignins. (ii) The hemicelluloses. (iii) The pectins. It cannot yet be claimed that any one of the products which can be assigned to these groups has been isolated in the form of a definite chemical entity (with the exception, perhaps, of some products in group iii). There are, however, certain characteristics common to each group, to which brief reference must be made. The lignins appear to be products of high molecular weight, which can be extracted by various somewhat drastic methods from woody tissues. The products obtained by different methods vary in their properties, but they appear to give definite colour reactions with a number of reagents.

scholarly journals High molecular weight SOA formation during limonene ozonolysis: insights from ultrahigh-resolution FT-ICR mass spectrometry characterization

2012 ◽  
Vol 12 (1) ◽  
pp. 2167-2197
Author(s):  
S. Kundu ◽  
R. Fisseha ◽  
A. L. Putman ◽  
T. A. Rahn ◽  
L. R. Mazzoleni
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Homologous Series ◽  
Condensation Reaction ◽  
Reaction Pathways ◽  
Ultrahigh Resolution ◽  
Group Iii ◽  
Group Ii ◽  
Ft Icr

Abstract. The detailed molecular composition of secondary organic aerosols (SOA) from limonene ozonolysis was studied using ultrahigh-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. High molecular weight (MW) compounds (m/z > 300) were found to constitute a significant number fraction of the identified SOA components. Double bond equivalents (DBE = the number of rings plus the number of double bonds) increased with MW. The O:C ratios and relative abundances of compounds decreased with increasing MW. The mass spectra of limonene contain 4 distinct clusters of negative ions: Group I (140 < m/z < 300), Group II (300 < m/z < 500), Group III (500 < m/z < 700) and Group IV (700 < m/z < 850). A number of CH2 and O homologous series of low MW SOA (Group 1) with carbon number 7–15 and oxygen number 3–9 were observed. Their occurrence can be explained with isomerization and elimination reactions of Criegee radicals, reactions between alkyl peroxy radicals, and scission of alkoxy radicals resulting from the Criegee radicals. Additionally, fragmentation analysis and observations of formaldehyde homologous series provide evidence for aerosol growth by the reactive uptake of generated gas-phase carbonyls in limonene ozonolysis. The decreasing O:C ratios between group of compounds indicated the importance of condensation (aldol and esterification) reaction pathways for high MW compound formation. However, the prominent DBE changes of 2 between the groups of compounds and selected fragmentation (MS/MS) analysis of Group II and Group III ions indicated a predominance of non-condensation (hydroperoxide, Criegee and hemi-acetal) reaction pathways. A reaction matrix created with the combination of low MW SOA, hydroperoxides, and Criegee radicals indicated higher frequencies for the hemi-acetal and condensation reaction pathways. Overall, the combined approach confirms the importance of non-condensation reaction pathways over condensation reaction pathways. Among the non-condensation reaction pathways, hemi-acetal reactions appear to be most dominant followed by hydroperoxide and Criegee reactions.

scholarly journals Histochemische Untersuchungen nach subkutaner bzw. intramuskulärer Applikation von hochmolekularen Eisenpolysaccharid-Präparaten bei Saugferkeln

1967 ◽  
Vol 4 (1) ◽  
pp. 58-68
Author(s):  
S. Ueberschär ◽  
W. Bollwahn
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Iron Hydroxide ◽  
The Body ◽  
Trivalent Iron ◽  
Iron Compounds ◽  
Chemical Changes ◽  
Bivalent Iron ◽  
Therapeutic Doses ◽  
Organic Residual

Subcutaneous or intramuscular injections of high molecular weight iron polysaccharides (Myofer 100® and Pigdex 100®) in therapeutic doses were given to pigs. These are taken up in macrophages between 6 and 24 hours following injection. If the material is finely divided, there occurs extracellularly and also in every case intracellularly a quick transformation from trivalent iron hydroxide to bivalent iron compounds; this process is essentially complete two days following injection. The high molecular weight polysaccharide is split off intracellularly from the iron components and is subject to its own chemical changes in the body. Accompanying this, in connection with the intracellular deposition of iron, there occurs the formation of an organic residual agent which is composed of mucopolysaccharides, glycoproteins and a matrix of protein and lipid.

Galactose loss and fruit ripening: high-molecular-weight arabinogalactans in the pectic polysaccharides of fruit cell walls

Planta ◽  
1997 ◽  
Vol 203 (2) ◽  
pp. 174-181 ◽  
Author(s):  
Robert J. Redgwell ◽  
Monica Fischer ◽  
Emma Kendal ◽  
Elspeth A. MacRae
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Fruit Ripening ◽  
Cell Walls ◽  
Pectic Polysaccharides

scholarly journals Changes in the Physico-chemical Properties of Peach Fruit Pectin during On-tree Ripening and Storage

1993 ◽  
Vol 118 (3) ◽  
pp. 343-349 ◽  
Author(s):  
M.L. Fishman ◽  
B. Levaj ◽  
D. Gillespie ◽  
R. Scorza
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Intrinsic Viscosity ◽  
Cell Walls ◽  
Prunus Persica ◽  
Chemical Properties ◽  
Radius Of Gyration ◽  
Weight Percentage ◽  
Pectin Content ◽  
Cell Wall Polymers

Radius of gyration (size), intrinsic viscosity, molecular weight, percentage of galacturonate, and percentage of neutral sugars were measured for chelate-soluble (CSP) and alkaline-soluble (ASP) pectins extracted from the cell walls of melting flesh (MF) and nonmelting flesh (NMF) peach [Prunus persica (L.) Batsch]. Weight percentage of cell walls, pectin content, and firmness were measured also. Peaches were extracted at 20, 21, and 22 weeks after flowering (WAF) and after various lengths of shelf storage at 25 ± 2C for the peaches picked at 21 WAF. Weight percentage of cell walls and firmness decreased markedly between the 21st and 22nd WAF; and between the 3rd and 6th day of storage for MF peaches as compared to NMF peaches. During these same periods, there were marked drops in the pectin content and the uronide content for MF as compared to NMF peaches. Size and intrinsic viscosity dropped markedly for CSP of MF peaches in comparison with NMF peaches during these same periods, whereas the molecular weight of CSP and ASP increased in MF peaches over that measured for NMF peaches. These results suggested that α -D-galacturonase (E.C. 3.2.1.15) was involved in softening only in the latter stages of ripening MF peaches. Further, cell wall polymers containing long thin pectin aggregates were destroyed, whereas cell wall polymers containing short thick pectin aggregates remained.

scholarly journals Yeast cell-wall synthesis

1969 ◽  
Vol 115 (2) ◽  
pp. 231-240 ◽  
Author(s):  
R. Sentandreu ◽  
D. H. Northcote
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Yeast Cell ◽  
High Molecular Weight ◽  
Peptide Synthesis ◽  
Yeast Cell Wall ◽  
Low Molecular Weight ◽  
Cell Wall Synthesis

1. A study of wall synthesis has been made by following the incorporation of radioactive glucose and threonine into the cytoplasm and wall of yeast. 2. Both glucose and threonine are incorporated into a mannan glycopeptide. The glucose is also synthesized into a structural glucan of the wall. 3. The mannan glycopeptide contains high-molecular-weight mannan and low-molecular-weight mannose and oligosaccharide units composed of mannose. Both types of carbohydrate are attached to the peptide. The extent of radioactive incorporation into these different carbohydrate constituents of the glycopeptide remained constant during a pulse-chase experiment. No evidence of a sequential synthesis of oligosaccharides and high-molecular-weight mannan was obtained. 4. Cycloheximide inhibits the incorporation of threonine into the wall but only partially inhibits the incorporation of glucose. Thus not all the polysaccharide deposited into the wall is dependent on a simultaneous peptide synthesis and incorporation. 5. Protoplasts grown in an iso-osmotic medium secreted a mannan polymer that was probably a glycopeptide.

Do Proline-rich Proteins Modulate a Transglutaminase Catalyzed Mechanism of Candidal Adhesion?

1993 ◽  
Vol 4 (3) ◽  
pp. 293-299 ◽  
Author(s):  
S.D. Bradway ◽  
M.J. Levine
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
High Molecular Weight ◽  
Surface Proteins ◽  
Cross Linking ◽  
Cell Wall Proteins ◽  
Epithelial Surface ◽  
High Molecular Weight Complex ◽  
Sds Page ◽  
Cross Links

Previously, we reported that a membrane-bound epithelial enzyme, transglutaminase (TGase), catalyzes the covalent cross-linking of acidic proline-rich proteins (APRPs) to surface proteins of buccal epithelial cells (BECs). The purpose of this study was twofold: (1) to provide evidence that TGase stabilizes C. albicans adhesion by covalently cross-linking C. albicans and BEC surface proteins and (2) to implicate PRPs in the modulation of this adhesive mechanism. The reactivity of candidal cell wall proteins with TGase was assessed in two separate experiments. Initially, following incubation with native BECs, the cross-linking of iodinated candidal cell wall proteins into high-molecular-weight complexes, as shown by SDS-PAGE/ autoradiography, was inhibited by the TGase inhibitor iodoacetamide. Additionally, [14C]putrescine in the presence of purified TGase, but not [14C]putrescine alone, was shown by SDS-PAGE/fluorography to be cross-linked into surface proteins of both morphogenetic forms (blastospore > hyphal forms) of C. albicans. In adherence assays, a component of both blastospore and hyphal form Candida/BEC adherence was shown to be resistant to detachment by heating adherent cells in 1% SDS at 100°C. However, pretreatment of BECs with iodoacetamide decreased SDS resistant adherence of both forms of C. albicans by =75%. When incubated with [125I]APRPs and purified TGase, both morphogenetic forms of C. albicans bound dramatically more APRP than controls without TGase. [125I]APRP binding in experimental, but not control, samples was resistant to repeated extraction (48 h) with 4% SDS/10% β-mercaptoethanol at 65°C, suggesting that [125I]APRPs were cross-linked to the Candida surface. SDS-PAGE/fluorography was used to verify that APRPs, in Lyticase digests of Candida cell walls, were cross-linked into a high-molecular-weight complex. These experiments suggest that epithelial TGase may stabilize Candida adherence by cross-linking Candida and BEC surface proteins. Additionally, because TGase cross-links APRPs to candidal and epithelial surface proteins, APRPs may interfere with TGase catalyzed mechanisms of adhesion. Supported by USPHS grants DE00185, DE07585, and OSU Seed grant.

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