THE LYSIS OF ACETOBACTER XYLINUM

1962 ◽  
Vol 8 (6) ◽  
pp. 841-846 ◽  
Author(s):  
T. E. Webb ◽  
J. Ross Colvin
Keyword(s):  
Cell Population ◽  
Local Area ◽  
Oxidative Capacity ◽  
Acetobacter Xylinum ◽  
Sensitive Species ◽  
Citrate Buffer ◽  
Whole Cells ◽  
Size And Shape ◽  
Phosphate Citrate Buffer

Lysis of about 90% of the cells of Acetobacter xylinum by lysozyme may be obtained after 2 hours at pH 8.1 in phosphate–citrate buffer. The cell population is heterogeneous since the remaining 10% of the cells do not lyse, even on repetition of the above treatment. The lysozyme does not cause the dissolution of all the bacterial wall, as in other lysozyme-sensitive species, but appears to attack only a limited, local area on the surface of the bacterium. Following the local weakening of the wall, the cell contents escape into the medium leaving a distinct "hull" with the same size and shape as the cell. The oxidative capacity of the lysed cells is the same as that of the whole cells. Reasons for the heterogeneity of the bacterial wall, both within and between cells, remain obscure.

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.

Preparation of a Factor VII Concentrate

1979 ◽  
Author(s):  
A.J. MacLeod ◽  
I. Dickson
Keyword(s):  
Specific Activity ◽  
Fresh Frozen Plasma ◽  
Factor Vii ◽  
Batch Adsorption ◽  
Citrate Buffer ◽  
Linear Gradient ◽  
Fresh Frozen ◽  
Frozen Plasma ◽  
Phosphate Citrate Buffer

A factor VII concentrate has been prepared from pooled citrated fresh frozen plasma following removal of cryoprecipitate and factors II, IX and X. The method involved batch adsorption on DEAE-Sephadex A-50, fractionation of the subsequent batch eluate by PEG precipitation and passage through a column of DEAE-Sepharose CL-.6B. A phosphate-citrate buffer pH 6.9 was used throughout, this was made 0.2M with NaCl for the batch elution and a 0 - 0.2H NaCl linear gradient was used to elute the components from the column. Factor VII activity was clearly resolved from the bulk of the protein, including caeruloplasmin, and could be recovered as a concentrate at about 20 U FVII/ml with a specific activity of in excess of 1 U FVII/mg of protein and an overall recovery of 40% to 50%

Determination of fumonisins B1 and B2 in maize-based baby food products by HPLC with fluorimetric detection after immunoaffinity column clean-up

2010 ◽  
Vol 3 (2) ◽  
pp. 135-146 ◽  
Author(s):  
A. De Girolamo ◽  
D. Pereboom-de Fauw ◽  
E. Sizoo ◽  
H. van Egmond ◽  
L. Gambacorta ◽  
...  
Keyword(s):  
High Performance ◽  
Signal To Noise Ratio ◽  
Retail Market ◽  
Immunoaffinity Column ◽  
Limit Of Quantification ◽  
Citrate Buffer ◽  
Relative Standard ◽  
Phosphate Citrate Buffer ◽  
Infants And Young Children

A method for the determination of fumonisin B1 (FB1) and B2 (FB2) in different commercial maize-based products for infants and young children was developed and tested in a limited validation study involving 3 laboratories. The method used extraction at 55 °C with an acidic mixture of methanol-acetonitrile-phosphate/citrate buffer, clean-up through immunoaffinity column and fumonisin determination by high performance liquid chromatography with automated pre-column derivatisation with o-phthaldialdehyde. Recovery experiments were performed at five spiking levels in the ranges of 80-800 µg/kg FB1 and 20-200 µg/kg FB2. Mean recoveries ranged from 83 to 97% for FB1 and from 61 to 78% for FB2. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 5 to 12% for FB1 and from 8 to 13% for FB2, whereas relative standard deviation for between-laboratory reproducibility (RSDR) ranged from 6 to 10% for FB1 and from 9 to 16% for FB2. The limit of quantification of the method (signal to noise ratio of 6) was 2.8 µg/kg for FB1 and 2.2 µg/kg for FB2. Fumonisins were found in 6 out of 19 maize-based baby foods obtained from the Italian retail market at levels up to 53 µg/kg.

Phosphate/citrate buffer

2008 ◽  
Vol 2008 (5) ◽  
pp. pdb.rec11328-pdb.rec11328 ◽  
Keyword(s):  
Citrate Buffer ◽  
Phosphate Citrate Buffer

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.

scholarly journals A rapid method to determine the bactericidal activity of compounds against non-replicatingMycobacterium tuberculosisat low pH

2019 ◽  
Author(s):  
Julie V. Early ◽  
Steven Mullen ◽  
Tanya Parish
Keyword(s):  
Bactericidal Activity ◽  
Minimum Bactericidal Concentration ◽  
Treatment Time ◽  
Low Ph ◽  
Citrate Buffer ◽  
Colony Forming Units ◽  
Carbonyl Cyanide ◽  
Viable Bacteria ◽  
Phosphate Citrate Buffer ◽  
Assay Conditions

AbstractThere is an urgent need for new anti-tubercular agents which can lead to a shortened treatment time by targeting persistent or non-replicating bacilli. In order to assess compound activity against non-replicatingMycobacterium tuberculosis, we developed a method to detect the bactericidal activity of novel compounds within 7 days. Our method uses incubation at low pH in order to induce a non-replicating state. We used a strain ofM. tuberculosisexpressing luciferase; we first confirmed the linear relationship between luminescence and viable bacteria (determined by colony forming units) under our assay conditions. We optimized the assay parameters in 96-well plates in order to achieve a reproducible assay. Our final assay usedM. tuberculosisin phosphate-citrate buffer, pH 4.5 exposed to compounds for 7 days; viable bacteria were determined by luminescence. We recorded the minimum bactericidal concentration at pH 4.5 (MBC4.5) representing >2 logs of kill. We confirmed the utility of the assay with control compounds. The ionophores monensin, niclosamide, and carbonyl cyanide 3-chlorophenylhydrazone and the anit-tubercular drugs pretomanid and rifampicin were active, while several other drugs such as isoniazid, ethambutol, and linezolid were not.

scholarly journals Estudo do comportamento eletroquímico da enzima peroxidase na presença de peróxido de hidrogênio e ácido 5- aminossalicílico

2018 ◽  
Vol 33 (1) ◽  
pp. 57
Author(s):  
Carolina Venturini Uliana ◽  
Carla Dos Santos Riccardi ◽  
Hideko Yamanaka
Keyword(s):  
Hydrogen Peroxide ◽  
Electrochemical Behavior ◽  
Oxidation Reaction ◽  
Supporting Electrolyte ◽  
Aminosalicylic Acid ◽  
Applied Potential ◽  
Cathodic Current ◽  
Citrate Buffer ◽  
Graphite Electrodes ◽  
Phosphate Citrate Buffer

The electrochemical behavior of the enzyme peroxidase (HRP) was investigated using the hydrogen peroxide as enzymatic substrate and the 5-aminosalicylic acid (5-ASA) as mediator of electrons on graphite electrodes. Several parameters were optimized, namely, the applied potential to the amperometric technique fixed in -0.125V, the 0.1 mol L-1 phosphate-citrate buffer at pH 5.0 as supporting electrolyte and the proportion between the 5-ASA and H2O2 in 1:7, among others. It was observed the catalysis of the oxidation reaction of the H2O2 in the presence of the enzyme HRP and 5-ASA. The oxidation product was reduced in the electrode surface, evidencing a significant increase in the intensity of the cathodic current.

scholarly journals The role of ubiquinone in the respiratory chain of Acetobacter xylinum

1968 ◽  
Vol 108 (2) ◽  
pp. 311-316 ◽  
Author(s):  
Moshe Benziman ◽  
H. Goldhamer
Keyword(s):  
Respiratory Chain ◽  
Nadh Oxidase ◽  
Coenzyme Q ◽  
Spectroscopic Properties ◽  
Acetobacter Xylinum ◽  
Whole Cells ◽  
Oxidation Reduction ◽  
The Individual ◽  
Ubiquinone 10

1. Whole cells of Acetobacter xylinum were found to contain a quinone of the ubiquinone (coenzyme Q) group. The quinone was isolated from the cells and crystallized. It was identified by its physical, chemical and spectroscopic properties as a ubiquinone with 10 isoprene units (ubiquinone-10). No naphthaquinone was detected in the cells. 2. Cell-free extracts prepared by means of a French pressure cell were separated into three fractions by differential centrifugation. The ubiquinone was located predominantly in the particulate fraction sedimenting at 33000g, which also contained most of the NADH oxidase and malate oxidase activities. The concentration of ubiquinone-10 in extracts was similar to that of the flavoproteins and about three times the concentration of the individual cytochromes. 3. Aerobic incubations of crude extracts with either NADH or malate resulted in reduction of the endogenous ubiquinone-10 to steady-state concentrations of 55 and 40% of the total quinone respectively. In the presence of cyanide more than 95% of the endogenous ubiquinone-10 was reduced by either NADH or malate. 4. The initial rate of reduction of endogenous ubiquinone-10 by malate and the rate of ubiquinol oxidation, in A. xylinum extracts, were found to be compatible with the overall rate of malate oxidation with oxygen. 5. The effects of various respiratory inhibitors on the oxidation–reduction reactions of the endogenous quinone indicate that its position on the respiratory chain is between the malate flavoprotein dehydrogenase and the cytochrome chain.

scholarly journals Fungicidal mechanism of action of D0870 against Cryptococcus neoformans under acidic conditions.

1997 ◽  
Vol 41 (12) ◽  
pp. 2710-2713 ◽  
Author(s):  
H Yamada ◽  
T Watanabe ◽  
K Kato ◽  
H Mochizuki
Keyword(s):  
Cell Membrane ◽  
Cryptococcus Neoformans ◽  
Ergosterol Biosynthesis ◽  
Spectrometric Analysis ◽  
Citrate Buffer ◽  
Unknown Lipid ◽  
Marked Accumulation ◽  
Acidic Conditions ◽  
Phosphate Citrate Buffer ◽  
Chromatographic Mass

The fungicidal mechanism of the triazole D0870 against Cryptococcus neoformans under acidic conditions was investigated. D0870 reduced the intracellular K+ content of C. neoformans at pH 4 to about half the value at pH 7 after 12 h of incubation. The 50% inhibitory concentrations of D0870 for ergosterol biosynthesis were almost the same at both pH 4 (0.017 microg/ml) and 7 (0.014 microg/ml); however, D0870 caused a marked accumulation of an unknown lipid and methylated sterols in C. neoformans cultured at pH 4. Extracted fractions containing the unknown lipid or methylated sterols showed strong fungicidal activities against C. neoformans both at pH 4 and 7 in phosphate-citrate buffer not containing D0870. Gas chromatographic-mass spectrometric analysis showed that the unknown lipid was obtusifolione. These results suggest that D0870 kills C. neoformans by disturbing the permeability of the cell membrane through the accumulation of obtusifolione and methylated sterols in the cell membrane under acidic conditions.

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