Structure of cell wall and exocellular mannans from the yeast Hansenula holstii
22
Citation
32
Reference
10
Related Paper
Citation Trend
Keywords:
Mannan
Phosphodiester bond
Autolysis (biology)
Autolysis (biology)
Cite
Citations (55)
Autolysis (biology)
Lysostaphin
Teichoic acid
Autolysin
Lytic cycle
Lysin
Cite
Citations (59)
Autolysis (biology)
Cite
Citations (7)
Cells of Clostridium botulinum type A strain 190 harvested at logarithmic growth phase rapidly autolysed in phosphate buffer and most of the cells were converted autolytically into spheroplasts in 0.5 M sucrose-phosphate buffer within 2–3 hr at 37 C. Electron microscope observations on the process of autolysis and spheroplast formation revealed that lysis of the cell wall commenced at one end of the cell and the cytoplasmic contents were released through such lesion. The rod cell was thusly transformed into a fragile spherical form in the hypertonic sucrose-buffer. The lysis of the cell wall proceeded centripetally and finally morphological integrity of the cell wall was completely lost. From these findings it is suggested that the autolysis of the organism is preceded by autodigestion of the cell wall at one end of the cell. A crude cell wall fraction isolated from log-phase cultures by sonication and fractionation rapidly autolysed in phosphate buffer. Reducing sugars and amino sugars of the wall were released from the autolysing wall fraction. Electron microscopy of the residues obtained from wall-autolysates demonstrated that the rigid structure of the wall completely disappeared and only fragile membranous or amorphous fragments remained after autolysis of the crude wall fraction. Heated wall preparations digested with trypsin and nagarse were dissolved by a soluble wall-autolysate, but not by a soluble cytoplasmic fraction. It seems likely that autolytic enzyme(s) may exist at or near the cell wall.
Autolysis (biology)
Spheroplast
Cell disruption
Cite
Citations (30)
Dendrobium officinale is a precious traditional Chinese medicinal plant because of its abundant polysaccharides found in stems. We determined the composition of water-soluble polysaccharides and starch content in D. officinale stems. The extracted water-soluble polysaccharide content was as high as 35% (w/w). Analysis of the composition of monosaccharides showed that the water-soluble polysaccharides were dominated by mannose, to a lesser extent glucose, and a small amount of galactose, in a molar ratio of 223:48:1. Although starch was also found, its content was less than 10%. This result indicated that the major polysaccharides in D. officinale stems were non-starch polysaccharides, which might be mannan polysaccharides. The polysaccharides formed granules and were stored in plastids similar to starch grains, were localized in D. officinale stems by semi-thin and ultrathin sections. CELLULOSE SYNTHASE-LIKE A (CSLA) family members encode mannan synthases that catalyze the formation of mannan polysaccharides. To determine whether the CSLA gene from D. officinale was responsible for the synthesis of mannan polysaccharides, 35S:DoCSLA6 transgenic lines were generated and characterized. Our results suggest that the CSLA family genes from D. officinale play an important role in the biosynthesis of mannan polysaccharides.
Mannan
Glucomannan
Monosaccharide
Cite
Citations (49)
Pectin
Xyloglucan
Cite
Citations (25)
Earlier studies have shown that the outer layers of the conidial and mycelial cell walls of Aspergillus fumigatus are different. In this work, we analyzed the polysaccharidome of the resting conidial cell wall and observed major differences within the mycelium cell wall. Mainly, the conidia cell wall was characterized by (i) a smaller amount of α-(1,3)-glucan and chitin; (ii) a larger amount of β-(1,3)-glucan, which was divided into alkali-insoluble and water-soluble fractions, and (iii) the existence of a specific mannan with side chains containing galactopyranose, glucose, and N-acetylglucosamine residues. An analysis of A. fumigatus cell wall gene mutants suggested that members of the fungal GH-72 transglycosylase family play a crucial role in the conidia cell wall β-(1,3)-glucan organization and that α-(1,6)-mannosyltransferases of GT-32 and GT-62 families are essential to the polymerization of the conidium-associated cell wall mannan. This specific mannan and the well-known galactomannan follow two independent biosynthetic pathways.
Mannan
Cite
Citations (13)
How the diverse polysaccharides present in plant cell walls are assembled and interlinked into functional composites is not known in detail. Here, using two novel monoclonal antibodies and a carbohydrate-binding module directed against the mannan group of hemicellulose cell wall polysaccharides, we show that molecular recognition of mannan polysaccharides present in intact cell walls is severely restricted. In secondary cell walls, mannan esterification can prevent probe recognition of epitopes/ligands, and detection of mannans in primary cell walls can be effectively blocked by the presence of pectic homogalacturonan. Masking by pectic homogalacturonan is shown to be a widespread phenomenon in parenchyma systems, and masked mannan was found to be a feature of cell wall regions at pit fields. Direct fluorescence imaging using a mannan-specific carbohydrate-binding module and sequential enzyme treatments with an endo-β-mannanase confirmed the presence of cryptic epitopes and that the masking of primary cell wall mannan by pectin is a potential mechanism for controlling cell wall micro-environments.
Mannan
Hemicellulose
Pectin
Secondary cell wall
Cite
Citations (249)
Summary We describe preparations of plant cell walls and polysaccharides obtained from plant cell walls that are added to food products for two purposes: as modifiers of food texture and/or as dietary fibres with potential health benefits. Although a number of different types of plant cell walls occur, only some are presently exploited. Commercial ‘fibre preparations’ range from those containing mostly primary walls to those containing mostly lignified secondary walls from which much of the lignin and non‐cellulosic polysaccharides have been removed. Preparations of cell‐wall polysaccharides are obtained from the following sources: cellulose mostly from secondary walls of cotton and wood, pectin from primary walls of dicotyledons, and (1→3),(1→4)‐ β ‐glucans and arabinoxylans from primary walls of cereal grains. Preparations of galactomannans, xyloglucans and the pectic polysaccharide rhamnogalacturonan I are obtained from non‐lignified secondary walls of certain leguminous seeds. The compositions, functionalities, uses and possible health benefits of these different preparations are discussed.
Pectin
Secondary cell wall
Xyloglucan
Food Products
Cite
Citations (169)
Cell walls from exponential-phase cultures of Streptococcus faecalis ATCC 9790 autolyzed in dilute buffers. Walls were isolated from cultures grown in the presence of 14 C-lysine for about 10 generations and then on 12 C-lysine for 0.1 to 0.8 of a generation (prelabeled). These walls released 14 C to the soluble fraction more slowly than they lost turbidity during the initial stages of autolysis. Walls isolated from cultures grown in the presence of 14 C-lysine for only the last 0.1 to 0.4 of a generation (postlabeled) released 14 C to the supernatant fluid more rapidly than they lost turbidity. Autolysin in both pre- and postlabeled walls was inactivated, and such walls were then incubated in the presence of unlabeled walls containing active autolysin. The inactivated walls lost their 14 C label only very slowly until autolysis of the unlabeled walls was virtually complete and release of soluble autolysin was expected. When this experiment was done in the presence of trypsin, a fourfold increase in the autolysis rate resulted, but the same pattern of 14 C release was observed. A parallel release of 14 C and loss of turbidity from pre- or postlabeled walls was observed upon trypsin “activation” and by addition of isolated soluble autolysin to inactivated walls. We conclude that the wall-bound autolysin acts first on the more recently synthesized portion of the wall. Trypsin appears to speed wall autolysis by activating additional latent autolysin in situ at sites in the older portion of the wall.
Autolysin
Autolysis (biology)
Cite
Citations (81)