THE EFFECT OF BACTERIAL CELL LYSIS AND OF PLANT EXTRACTS ON CELLULOSE PRODUCTION BY ACETOBACTER XYLINUM

1963 ◽  
Vol 41 (1) ◽  
pp. 1691-1702 ◽  
Author(s):  
T. E. Webb ◽  
J. Ross Colvin
Keyword(s):  
Bacterial Cell ◽  
Cell Envelope ◽  
Acetobacter Xylinum ◽  
Cellulose Synthesis ◽  
Additive Effects ◽  
Cellulose Production ◽  
Whole Cells ◽  
Negative Results ◽  
Heat Stable ◽  
Plant Sources

The production of cellulose by lysozyme lysates of Acetobacter xylinum is similar to that of a suspension of whole cells, in contrast to the negative results obtained with previous "cell-free" preparations. The results of differential centrifugation of these lysates suggests that most of the enzymes required for cellulose synthesis from glucose normally are held by the cell envelope and are not located in the cytoplasm. However, a heat-stable cofactor(s) is present in the supernatant derived from the cell contents which may stimulate cellulose synthesis by the cell envelopes.The addition of extracts from a number of plant sources increased cellulose synthesis by whole cells of A. xylinum. In particular, the supernatant prepared by centrifugation of an homogenate of tomatoes increased bacterial cellulose production at pH 6 by a factor of 3. Both dialyzable and non-dialyzable substances in the extract are responsible. Fractionation of the non-dialyzable portion of the extract by column chromatography suggests that the overall increase is due to additive effects of several compounds. Here also the compounds appear to act upon the bacterial cell envelope.

THE EFFECT OF BACTERIAL CELL LYSIS AND OF PLANT EXTRACTS ON CELLULOSE PRODUCTION BY ACETOBACTER XYLINUM

1963 ◽  
Vol 41 (8) ◽  
pp. 1691-1702 ◽  
Author(s):  
T. E. Webb ◽  
J. Ross Colvin
Keyword(s):  
Bacterial Cell ◽  
Cell Envelope ◽  
Acetobacter Xylinum ◽  
Cellulose Synthesis ◽  
Additive Effects ◽  
Cellulose Production ◽  
Whole Cells ◽  
Negative Results ◽  
Heat Stable ◽  
Plant Sources

The production of cellulose by lysozyme lysates of Acetobacter xylinum is similar to that of a suspension of whole cells, in contrast to the negative results obtained with previous "cell-free" preparations. The results of differential centrifugation of these lysates suggests that most of the enzymes required for cellulose synthesis from glucose normally are held by the cell envelope and are not located in the cytoplasm. However, a heat-stable cofactor(s) is present in the supernatant derived from the cell contents which may stimulate cellulose synthesis by the cell envelopes.The addition of extracts from a number of plant sources increased cellulose synthesis by whole cells of A. xylinum. In particular, the supernatant prepared by centrifugation of an homogenate of tomatoes increased bacterial cellulose production at pH 6 by a factor of 3. Both dialyzable and non-dialyzable substances in the extract are responsible. Fractionation of the non-dialyzable portion of the extract by column chromatography suggests that the overall increase is due to additive effects of several compounds. Here also the compounds appear to act upon the bacterial cell envelope.

The biosynthesis of cellulose by Acetobacter xylinum and Acetobacter acetigenus

1977 ◽  
Vol 23 (6) ◽  
pp. 701-709 ◽  
Author(s):  
J. Ross Colvin ◽  
Gary G. Leppard
Keyword(s):  
Cell Envelope ◽  
Acetobacter Xylinum ◽  
Cellulose Microfibrils ◽  
Cellulose Synthesis ◽  
Electron Microscopic ◽  
Air Drying ◽  
Thin Sections ◽  
Morphological Aspects ◽  
Transmission Electron ◽  
Freeze Etching

The morphological aspects of biosynthesis of cellulose by Acetobacter xylinum and Acetobacter acetigenus were studied by transmission electron microscopy of both freeze-etch replicas and sections of cellulose-free cells in suspension culture before and subsequent to the induction of cellulose synthesis. Also examined were freshly synthesized, thoroughly washed, cellulose pellicles. Thin sections of rapidly dividing, glucose-metabolizing cells of both species showed irregular features on the cell surface including a small polar invagination which sometimes contained or was associated with fibrils as fine as 3 nm in diameter of a substance which stains with electron-microscopic counterstains. Cellulose microfibrils in thin sections of freshly synthesized pellicles were coated with a surface material which also stained with the same counterstains (uranyl ions and lead ions). The effect of air-drying on freshly synthesized cellulose was striking. When examined by freeze-etching, thoroughly washed, never air-dried pellicles of both species showed a nascent form of cellulose fibril which consisted of a central, dense core surrounded by a sheath of amorphous gel. This sheath may be up to 100 nm wide. When the pellicle was air-dried and rehydrated before freeze-etching, the amorphous sheath was rare and shrunken but ordinary microfibrils of classical dimensions were visible. The sheath and core are sometimes closely associated with the envelope of the cells of both species. These observations can be interpreted in the context of recent advances in cellulose synthesis by assuming that chains of an initial, highly hydrated, intermediate polyglucan are released from the cell and that such chains associate to form a nascent fibril external to the cell but associated with the cell envelope. Air-drying of nascent fibrils converts them to classical microfibrils and this conversion is considered here in molecular terms.

THE VARIABLE RELATION OF OXYGEN CONSUMPTION TO CELLULOSE SYNTHESIS BY ACETOBACTER XYLINUM

1964 ◽  
Vol 10 (1) ◽  
pp. 11-15
Author(s):  
T. E. Webb ◽  
J. Ross Colvin
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Acetobacter Xylinum ◽  
Cellulose Synthesis ◽  
Whole Cells ◽  
Constant Ph

Oxygen uptake by whole cells or lysed cells of A. xylinum at pH 8.0 is only 3% of that of the same preparation at pH 6.0. Because the amount of cellulose synthesized by both types of preparation is the same at pH 6.0 and pH 8.0, not more than 3% of the oxygen uptake of cells of A. xylinum at pH 6.0 is directly linked to cellulose formation. When tomato supernatant is used as a substrate at pH 6.0 an increase in cellulose synthesis is accompanied by a decrease in oxygen uptake by whole cells. Even at constant pH, oxygen consumption is therefore a poor measure of cellulose synthesis. In spite of the large fractions of available glucose incorporated into cellulose, only a very small part of the total metabolism of the organism is devoted to synthesis of cellulose.

scholarly journals User experience: Using national Cryo EM centers towards studying lipid transport across the bacterial cell envelope

2021 ◽  
Vol 27 (S1) ◽  
pp. 1422-1422
Author(s):  
Gira Bhabha ◽  
Damian Ekiert ◽  
Nicolas Coudray ◽  
Georgia Isom ◽  
Mark MacRae ◽  
...  
Keyword(s):  
User Experience ◽  
Bacterial Cell ◽  
Cell Envelope ◽  
Lipid Transport ◽  
Bacterial Cell Envelope

scholarly journals Evaluation of Recombinant Proteins of Burkholderia mallei for Serodiagnosis of Glanders

2012 ◽  
Vol 19 (8) ◽  
pp. 1193-1198 ◽  
Author(s):  
Vijai Pal ◽  
Subodh Kumar ◽  
Praveen Malik ◽  
Ganga Prasad Rai
Keyword(s):  
Sensitivity And Specificity ◽  
Recombinant Proteins ◽  
False Negative ◽  
Enzyme Linked Immunosorbent Assay ◽  
Burkholderia Mallei ◽  
Content Type ◽  
Whole Cells ◽  
Negative Results ◽  
Elisa Format ◽  
Low Sensitivity

ABSTRACTGlanders is a contagious disease caused by the Gram-negative bacillusBurkholderia mallei. The number of equine glanders outbreaks has increased steadily during the last decade. The disease must be reported to the Office International des Epizooties, Paris, France. Glanders serodiagnosis is hampered by the considerable number of false positives and negatives of the internationally prescribed tests. The major problem leading to the low sensitivity and specificity of the complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA) has been linked to the test antigens currently used, i.e., crude preparations of whole cells. False-positive results obtained from other diagnostic tests utilizing crude antigens lead to financial losses to animal owners, and false-negative results can turn a risk into a possible threat. In this study, we report on the identification of diagnostic targets using bioinformatics tools for serodiagnosis of glanders. The identified gene sequences were cloned and expressed as recombinant proteins. The purified recombinant proteins ofB. malleiwere used in an indirect ELISA format for serodiagnosis of glanders. Two recombinant proteins, 0375H and 0375TH, exhibited 100% sensitivity and specificity for glanders diagnosis. The proteins also did not cross-react with sera from patients with the closely related disease melioidosis. The results of this investigation highlight the potential of recombinant 0375H and 0375TH proteins in specific and sensitive diagnosis of glanders.

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