THE DEGRADATION OF 2-KETO-D-GLUCONATE-C14, D-GLUCONATE-C14, AND D-FRUCTOSE-C14 BY LEUCONOSTOC MESENTEROIDES

1957 ◽  
Vol 3 (5) ◽  
pp. 741-744 ◽  
Author(s):  
E. R. Blakley ◽  
A. C. Blackwood
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Leuconostoc Mesenteroides ◽  
Labeled Compounds ◽  
Radioactive Carbon

2-Ketogluconate, gluconate, and fructose specifically labeled with C14 were fermented by Leuconostoc mesenteroides. Radioactive carbon dioxide was recovered from the fermentation of the C-1 labeled substrates, while methyl labeled lactic acid was recovered from the C-6 labeled compounds. The results indicate that the metabolism of these compounds and that previously reported for glucose are similar. This organism can be used to degrade these compounds for the determination of C14 distribution.

THE METABOLISM OF 2-KETO-D-GLUCONATE BY CELL-FREE EXTRACTS OF LEUCONOSTOC MESENTEROIDES

1959 ◽  
Vol 5 (5) ◽  
pp. 547-560 ◽  
Author(s):  
O. Ciferri ◽  
E. R. Blakley
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Alcohol Dehydrogenase ◽  
Leuconostoc Mesenteroides ◽  
Acetyl Phosphate ◽  
Lactic Acid Dehydrogenase ◽  
Optimal Activity ◽  
Alternate Pathway ◽  
Optimum Ph

The degradation of 2-keto-D-gluconate by Leuconostoc mesenteroides is shown to proceed according to the following pathway: 2-keto-D-gluconate → 2-keto-6-phospho-D-gluconate → 6-phospho-D-gluconate → D-ribulose-5-phosphate + CO2 → D-xylulose-5-phosphate → acetyl-phosphate + D-glyceraldehyde-3-phosphate.Cells grown on 2-keto-D-gluconate were shown previously to possess an adaptive and specific 2-ketogluconokinase. These cells also contained a reductase that reduced 2-keto-6-phospho-D-gluconate to 6-phospho-D-gluconate in the presence of DPNH or TPNH, 6-phospho-D-gluconate-dehydrogenase, phosphoketolase, D-ribulose-5-phosphate-3-epimerase, and acetokinase. The 2-keto-6-phospho-D-gluconate-reductase which was also present in cells grown on D-gluconate shows optimal activity between pH 4.5 and 6.5 and is rapidly inactivated by heat. The 6-phospho-D-gluconate-dehydrogenase specific for DPN has an optimum pH between 7.2 and 7.7 and is stable when heated to 50 °C for 5 minutes.The production of carbon dioxide or pentulose-phosphate with extracts from cells grown on 2-keto-D-gluconate proceeded more rapidly with 2-keto-6-phospho-D-gluconate as the substrate than with 6-phospho-D-gluconate. This difference in rates was eliminated if a system to recycle hydrogen such as alcohol dehydrogenase and acetaldehyde or pyruvate to couple with lactic acid dehydrogenase was provided. Thus the existence of an alternate pathway for the catabolism of 2-keto-6-phospho-D-gluconate to carbon dioxide, acetic acid, and lactic acid does not appear to exist.

THE METABOLISM OF 2-KETO-D-GLUCONATE BY RESTING CELLS OF LEUCONOSTOC MESENTEROIDES

1960 ◽  
Vol 6 (1) ◽  
pp. 107-114
Author(s):  
E. R. Blakley ◽  
A. C. Blackwood
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Column Chromatography ◽  
Leuconostoc Mesenteroides ◽  
Fermentation Medium ◽  
Resting Cells

The rate of utilization of 2-keto-D-gluconate and the accumulation of pentulose by resting cells of Leuconostoc mesenteroides is affected markedly by pH, Below pH 5, 2-keto-D-gluconate is utilized slowly and pentulose accumulates in the fermentation medium. The pentulose was separated by column chromatography and identified as D-xylulose and D-ribulose. The products of the fermentation of 2-keto-D-gluconate by resting cells, in addition to pentulose, are carbon dioxide, acetic acid, and lactic acid, as expected from the studies with growing cultures. The results obtained are unexpected when considered with what is known about the metabolism of 2-keto-D-gluconate by this organism.

262. The microbiology of silage made by the addition of mineral acids to crops rich in protein

1940 ◽  
Vol 11 (3) ◽  
pp. 243-265 ◽  
Author(s):  
A. Cunningham ◽  
A. M. Smith
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Leuconostoc Mesenteroides ◽  
Streptococcus Lactis ◽  
Acid Ratio ◽  
Mineral Acids ◽  
New Type ◽  
Inactive Group

1. The microflora of A.I.V. silage consists mainly of lactic acid bacteria—lactobacilli, streptococci, micrococci and sarcinae. Some samples also contain yeasts and yeast-like organisms.2. Among the lactobacilli, both homo- and heterofermentative types are represented. The former include strains ofLactobacillus plantarum(Orla- Jensen) Bergey et. al.; in the heterofermentative groupL. brevis(Orla-Jensen) Bergey et al. has been found.3. Cultures of a motile homofermentative lactobacillus were isolated; this appears to be a new type. Among the unidentified heterofermentative lactobacilli, forms which may prove to be similar to the inactive group of Pederson were encountered.4. The homofermentative streptococci were found to belong to the Streptococcus lactis group; the heterofermentative forms were identified withLeuconostoc mesenteroides(Cienkowski) van Tieghem.5. Strains of unidentified homofermentative micrococci and sarcinae were isolated and shown to possess characteristics not usually associated with organisms of these types.6. Streptococci, micrococci and motile lactobacilli were found mainly in fodder recently ensiled; the majority of the lactobacilli and sarcinae were associated with the older samples.7. The characteristics which proved to be most valuable for the differentiations of the organisms were ability to produce carbon dioxide, percentage of lactic acid formed and lactic-acetic acid ratio.

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