THE BIOSYNTHESIS OF CELL WALL CARBOHYDRATES: II. FORMATION OF CELLULOSE AND XYLAN FROM LABELED MONOSACCHARIDES IN WHEAT PLANTS

1955 ◽  
Vol 33 (1) ◽  
pp. 658-666 ◽  
Author(s):  
A. C. Neish
Keyword(s):  
Cell Wall ◽  
The Other ◽  
Main Route ◽  
Cell Wall Carbohydrates

D-Glucose-1-C14, D-allose-1-C14, D-ribose-1-C14, D-xylose-1-C14, and sedoheptulose-2-C14 were administered to Thatcher wheat plants. The cellulose and xylan were isolated after a 5–48 hr. period of metabolism, and converted to glucose and xylose, respectively. The distribution of C14 in both glucose and xylose was then determined by fermentation with Lcuconostoc mesentcroides. Glucose was found to be a better precursor of both cellulose and xylan than any of the other sugars. The distribution of C14 in the products strongly suggested that the main route for synthesis of the xylose units of xylan was by removal of carbon-6 from a hexose and that pentoses were converted to xylan only through a hexose intermediate.

THE BIOSYNTHESIS OF CELL WALL CARBOHYDRATES: II. FORMATION OF CELLULOSE AND XYLAN FROM LABELED MONOSACCHARIDES IN WHEAT PLANTS

1955 ◽  
Vol 33 (4) ◽  
pp. 658-666 ◽  
Author(s):  
A. C. Neish
Keyword(s):  
Cell Wall ◽  
The Other ◽  
Main Route ◽  
Cell Wall Carbohydrates

D-Glucose-1-C14, D-allose-1-C14, D-ribose-1-C14, D-xylose-1-C14, and sedoheptulose-2-C14 were administered to Thatcher wheat plants. The cellulose and xylan were isolated after a 5–48 hr. period of metabolism, and converted to glucose and xylose, respectively. The distribution of C14 in both glucose and xylose was then determined by fermentation with Lcuconostoc mesentcroides. Glucose was found to be a better precursor of both cellulose and xylan than any of the other sugars. The distribution of C14 in the products strongly suggested that the main route for synthesis of the xylose units of xylan was by removal of carbon-6 from a hexose and that pentoses were converted to xylan only through a hexose intermediate.

THE BIOSYNTHESIS OF CELL WALL CARBOHYDRATES: III. FURTHER STUDIES ON FORMATION OF CELLULOSE AND XYLAN FROM LABELED MONOSACCHARIDES IN WHEAT PLANTS

1956 ◽  
Vol 34 (1) ◽  
pp. 405-413 ◽  
Author(s):  
H. A. Altermatt ◽  
A. C. Neish
Keyword(s):  
Cell Wall ◽  
Leuconostoc Mesenteroides ◽  
Carbon Skeleton ◽  
The Other ◽  
Uridine Diphosphate ◽  
Uridine Diphosphate Glucose ◽  
Polysaccharide Synthesis ◽  
Diphosphate Glucose ◽  
Cell Wall Carbohydrates

D-Glucose-1-C14, D-glucose-2-C14, D-xylose-2-C14, D-xylose-5-C14, D-arabinose-1-C14, D-glucuronolactone-1-C14, D-glucitol-1-C14, D-mannitol-1-C14, D-arabitol-1-C14, and D-arabitol-5-C14 were administered to wheat plants. The cellulose and xylan were isolated after a period of metabolism varying from 2 to 23 hr. D-Mannitol and D-arabitol were not converted to either cellulose or xylan while D-arabinose was utilized slightly. The other compounds gave rise to both labelled cellulose and xylan. The glucose and xylose, obtained from the cellulose and xylan respectively, were degraded by fermentation with Leuconostoc mesenteroides. Glucose and glucuronolactone were equally good precursors of xylan and were superior to the other compounds tried. They appeared to give rise to units for xylan formation by loss of carbon-6. Free xylose was converted to xylan units only after an extensive rearrangement of the carbon skeleton, such as occurred in the conversion of xylose to cellulose units. A hypothetical outline of polysaccharide synthesis, involving uridine diphosphate glucose as the central intermediate, is suggested to explain the data.

THE BIOSYNTHESIS OF CELL WALL CARBOHYDRATES: IV. FURTHER STUDIES ON CELLULOSE AND XYLAN IN WHEAT

1958 ◽  
Vol 36 (1) ◽  
pp. 187-193 ◽  
Author(s):  
A. C. Neish
Keyword(s):  
Cell Wall ◽  
The Other ◽  
Cell Wall Carbohydrates

D-Glucose-1-C14, D-glucose-6-C14, D-mannose-1-C14, D-galactose-1-C14, D-glucuronolactone-1-C14, D-glucuronolactone-6-C14, potassium D-gluconate-6-C14, and L-arabinose-1-C14 were administered to wheat shoots. The cellulose and xylan were isolated after a 5 hour period of metabolism. Glucose was more readily converted to cellulose and xylan than any of the other compounds tested. The distribution of C14 in the glucose and xylose isolated from the polysaccharides indicates that xylan was formed from the aldohexoses and glucuronolactone by processes involving loss of carbon-6. L-Arabinose, unlike D-xylose and D-ribose, was converted to xylan with little rearrangement of the pentose skeleton.

THE BIOSYNTHESIS OF CELL WALL CARBOHYDRATES: IV. FURTHER STUDIES ON CELLULOSE AND XYLAN IN WHEAT

1958 ◽  
Vol 36 (2) ◽  
pp. 187-193 ◽  
Author(s):  
A. C. Neish
Keyword(s):  
Cell Wall ◽  
The Other ◽  
Cell Wall Carbohydrates

D-Glucose-1-C14, D-glucose-6-C14, D-mannose-1-C14, D-galactose-1-C14, D-glucuronolactone-1-C14, D-glucuronolactone-6-C14, potassium D-gluconate-6-C14, and L-arabinose-1-C14 were administered to wheat shoots. The cellulose and xylan were isolated after a 5 hour period of metabolism. Glucose was more readily converted to cellulose and xylan than any of the other compounds tested. The distribution of C14 in the glucose and xylose isolated from the polysaccharides indicates that xylan was formed from the aldohexoses and glucuronolactone by processes involving loss of carbon-6. L-Arabinose, unlike D-xylose and D-ribose, was converted to xylan with little rearrangement of the pentose skeleton.

THE BIOSYNTHESIS OF CELL WALL CARBOHYDRATES: III. FURTHER STUDIES ON FORMATION OF CELLULOSE AND XYLAN FROM LABELED MONOSACCHARIDES IN WHEAT PLANTS

1956 ◽  
Vol 34 (3) ◽  
pp. 405-413 ◽  
Author(s):  
H. A. Altermatt ◽  
A. C. Neish
Keyword(s):  
Cell Wall ◽  
Leuconostoc Mesenteroides ◽  
Carbon Skeleton ◽  
The Other ◽  
Uridine Diphosphate ◽  
Uridine Diphosphate Glucose ◽  
Polysaccharide Synthesis ◽  
Diphosphate Glucose ◽  
Cell Wall Carbohydrates

D-Glucose-1-C14, D-glucose-2-C14, D-xylose-2-C14, D-xylose-5-C14, D-arabinose-1-C14, D-glucuronolactone-1-C14, D-glucitol-1-C14, D-mannitol-1-C14, D-arabitol-1-C14, and D-arabitol-5-C14 were administered to wheat plants. The cellulose and xylan were isolated after a period of metabolism varying from 2 to 23 hr. D-Mannitol and D-arabitol were not converted to either cellulose or xylan while D-arabinose was utilized slightly. The other compounds gave rise to both labelled cellulose and xylan. The glucose and xylose, obtained from the cellulose and xylan respectively, were degraded by fermentation with Leuconostoc mesenteroides. Glucose and glucuronolactone were equally good precursors of xylan and were superior to the other compounds tried. They appeared to give rise to units for xylan formation by loss of carbon-6. Free xylose was converted to xylan units only after an extensive rearrangement of the carbon skeleton, such as occurred in the conversion of xylose to cellulose units. A hypothetical outline of polysaccharide synthesis, involving uridine diphosphate glucose as the central intermediate, is suggested to explain the data.

The Structure of Sycamore Callus Cells During Division in a Partially Synchronized Suspension Culture

1970 ◽  
Vol 6 (2) ◽  
pp. 299-321
Author(s):  
K. ROBERTS ◽  
D. H. NORTHCOTE
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Plate ◽  
Optical Microscope ◽  
The Other ◽  
Active Movement ◽  
Developmental Sequence ◽  
Golgi Bodies ◽  
Dividing Cells ◽  
Peripheral Cytoplasm

Sycamore suspension callus cells have been partially synchronized to give a culture with a mitotic index of 15%. Living dividing cells of the culture have been examined with Nomarski differential interference optics and a comparable study made on fixed cells with the electron microscope. An organized band of reticulate cytoplasm partially encircles the nucleus at mitosis. The cell divides by the formation of a phragmosome which grows across the large vacuole; this allows the organization of the cytoplasm which forms the cell plate to be examined separately from the more general cytoplasm of the cell. The cell plate grows from one side of the cell to the other and down its length a complete developmental sequence can be seen. The Golgi bodies and the endoplasmic reticulum are probably involved in the formation of material for the construction of the cell plate and young cell wall. Microfibrils are formed within the plate in the more mature regions, while material contained within vesicles is incorporated at the young growing edge. At the edge of the plate microtubules are found and these correspond to the fibrillar appearance of the phragmoplast seen with the optical microscope. In the living cell an active movement of organelles along the peripheral cytoplasm can be seen and with fixed cells viewed with the electron microscope microtubules are often found adjacent to the plasmalemma and lying close to mitochondria, crystal-containing bodies and plastids. The appearance of crystal-containing bodies and plastids containing phytoferritin is described.

scholarly journals The interaction between Histoplasma capsulatum cell wall carbohydrates and host components: relevance in the immunomodulatory role of histoplasmosis

2009 ◽  
Vol 104 (3) ◽  
pp. 492-496 ◽  
Author(s):  
Patricia Gorocica ◽  
Maria Lucia Taylor ◽  
Noé Alvarado-Vásquez ◽  
Armando Pérez-Torres ◽  
Ricardo Lascurain ◽  
...  
Keyword(s):  
Cell Wall ◽  
Histoplasma Capsulatum ◽  
Cell Wall Carbohydrates

Role of sinoatrial ring bundle in internodal conduction

1976 ◽  
Vol 231 (2) ◽  
pp. 319-325 ◽  
Author(s):  
M Hiraoka ◽  
T Sano
Keyword(s):  
Sinus Node ◽  
The Other ◽  
Wave Fronts ◽  
Av Node ◽  
Crista Terminalis ◽  
Main Route ◽  
Endocardial Surface ◽  
The Right ◽  
Activation Sequence

The role of the sinoatrial ring bundle (SARB) in internodal conduction was examined by the microelectrode technique in excised rabbit hearts. The spread of the sinus impluse to the surrounding tissues was shown to proceed anteriorly toward the right branch of the crista terminalis significantly faster than toward the other direction. Thus the right SARB and the right branch of the crista terminalis close to the sinus node were the earliest areas excited by the sinus impulse in the areas surrounding the sinus node. It was further shown that the activation sequence does not initiate from the right SARB to the right branch of the crista terminalis via the junction of these two structures. Cutting the SARB did not produce any delay in conduction from the sinus node to the atrioventricular (AV) node. The conduction velocity measured at the endocardial surface by two microelectrodes has proved that conduction in the crista terminalis was significantly faster than in the SARB. The upstroke of the action potential from the crista terminalis was also steeper than that from the SARB. These results suggest that the SARB is not the main route for impulse propagation from the sinus node to the AV node; the fastest internodal conduction therefore takes place with wide wave fronts, along the crista terminalis.

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