Certain Phases of Nitrogenous Metabolism in Bacterial Cultures

Bord, George G. De

doi:10.1128/jb.8.1.7-45.1923

Cited by 13 publications

(4 citation statements)

References 22 publications

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“…The results are given in table 5 and show that from 18 to 29 per cent of the amino nitrogen in the media was removed by the permutit. These results are in agreement with the findings of DeBord (1923) who reported that permutit was unsuitable for the removal of ammonia from bacterial cultures. Whitehorn (1923) has shown that the substances removed from solution by permutit are relatively strong bases.…”

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confidence: 93%

“…(1915) took liquefaction of gelatin and ammonia production as indexes, Itano (1916) employed changes in amino nitrogen and hydrogen ion concentration as measures and Berman and Rettger (1918) regarded the biuret test and changes in amino nitrogen as satisfactory criteria. Sears (1916), Waksman (1917), DeBord (1923) and Kendall, Day and Walker (1913) used both ammonia and amino-acid nitrogen determinations as methods for following protein decomposition. Kendall (1922), Kendall, Haner and Bly (1922) and Wagner, Dozier and Meyer (1924), used intermediate protein degradation products as well as ammonia and amrino nitrogen as criteria of proteolysis.…”

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The Proteolytic Action of Certain Lactic Acid Bacteria

1928

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Although the action of the lactic acid bacteria on carbohydrates has been the subject of many investigations, comparatively little attention has been paid to their proteolytic activity. Kulp and Rettger (1924) found that from 2 to 6 per cent of the proteins i milk were broken down by L. acidophilus and L. bulgaricus.Oila-Jensen (1919) studied the proteolytic action of a large number of lactic acid bacteria on the proteins of milk and Witte's peptone broth. In milk from 0 to 22.7 per cent of the total nitrogen was changed into soluble forms and in Witte's peptone the amino nitrogen produced varied from 0.5 to 33.9 per cent of the total. Ammonia nitrogen generally amounted to less than 2 per cent of the total nitrogen. Itano (1916) in studying the influence of hydrogen ion concentration upon the proteolytic activity of S. lacticus obtained an increase of 8.7 to 33.5 per cent in the amount of amino nitrogen. Sears (1916) reported that B. acidi-lactici produced much more ammomna and amino nitrogen when glucose was left out of the medium than when it was included.Various criteria have been used by different investigators as indexes of proteolysis. The early investigators, Smith (1897) and Peckham (1897), took putrefactive products as a test, Heller (1921) employed pH changes, Hall (1922) used liquefaction of coagulated proteins and gelatin as standards, Kendall and Walker 1 This work was supported in part by a grant from the special research fund of the University of Wisconsin. The authors are indebted to Miss Katherine M. Bolliger for assistance in the analytical work.

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The Proteolytic Action of Certain Lactic Acid Bacteria

1928

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“…Strain Fe (table 3) shows a tendency to do this. On the other hand the amino acids alone do not furnish a good index of proteolysis, as was assumed by DeBord (1923), because they may be more or less completely deaminized as was the case with all the nonfermentative anaerobes studied. However, the formol titration which includes ammonia, amino acids and the lower polypeptides is a very good index of proteolysis when any of these products are formed.…”

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“…Better and simpler methods of securing anaerobic conditions have been devised, such as various developments of the anaerobe jar of McIntosh and Fildes (1916) and the use of vaseline on the surface of media in test tubes. The contributions of Wolf and Harris (1917,1918,1919), Bushnell (1922), Kendall, Day andWalker (1922), andDeBord (1923) demonstrated the usefulness of biochemical methods for the study of the anaerobes and the impossibility of. understanding their activities without resort to such methods.…”

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A Study of Anaerobic Bacteria

Brown¹

1925

J Bacteriol

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Changes in the free amino and other nitrogen compounds in stored beef muscle

Gardner

1966

J Sci Food Agric

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Changes in the levels of 21 amino compounds, ammonium-N and urea-N. during the storage of fresh beef at various temperatures have been investigated. The meats were also subjected to bacteriological analysis. Glutathione and glutamine were found to decrease in the meats during storage, while most other aniinoacids, notably glutamic acid and tryptophan, increased. The increase in glutamic acid appeared to be related to the microbial numbers in the meats. On the other hand, the increase in tryptophan seemed directly related to the time and temperature of storage. There was an initial increase in urea-N followed by a gradual disappearance of this compound from the stored meats. Ammonium-N did not rise significantly until the stage of incipient spoilage had been reached. lntroduction Studies in the changes of individual free amino-acids in beef during storage have been the subject of numerous investigations,1-8 most of which are concerned with autolytic processes. However, Avshalumova5 examined the changes in the free amino-acids in meat during storage at 18-20' and at the same time observed the microbiological condition of the meat by a direct smear technique.The levels of ammonium N have also been evaluated as an index of microbial proteoly~is.~-~8 The most recent workers16-l* agree that it is an index of advanced rather than incipient putrefaction of flesh foods and is not a good index of spoilage. Recorded values for the ammonium N content of fresh meat show wide variations.5~ 1'J, 18 In this paper the changes in the levels of free amino-acids, ammonia, urea and the number and types of bacteria present in beef during storage have been examined to assess if any of the chemical criteria could be used as an index of incipient spoilage. Experimental Preparation of meatsExperiment 1 .-The source and preparation of the meats stored at 4", 9" and 15" has been described elsewhere by Gardner . @ Experiment 2.-The meats used in this experiment were taken from the foreleg muscles of cows within 3 h post mortem. The preparation of these was similar to that in Experiment I, except that in all cases the storage temperature was 15". Bacteriological analysisThe techniques and media employed in assessing the flora changes of the meats during storage have been previously described.lg Chemical analysisSamples were taken at the time of bacteriological analysis and stored at -20" until required. Protein and fat-free extracts of the meats were preparmed by the method of Awapara.20 +Present address : Ulster Curers' Association, 2 Greenwood Avenue, Belfast 4, N. Ireland. J. Sci. Fd Agric., 1966, Vol. 17,, NovemberAmino-acids.-Amino-acids were separated by the electrochromatographic procedure of Biserte et aL21 and quantitatively estimated by the method of Barrollier.22 Elution of the neutral amino-acids and basic amino-acids after primary separation was carried out by the method of Finkle.23 Glutamine was estimated as glutamic acid after the neutral amino-acid fraction of each sample had been hydrolysed in 2~ sulphuric acid for 60 min. a...

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Certain Phases of Nitrogenous Metabolism in Bacterial Cultures

Cited by 13 publications

References 22 publications

The Proteolytic Action of Certain Lactic Acid Bacteria

The Proteolytic Action of Certain Lactic Acid Bacteria

A Study of Anaerobic Bacteria

Changes in the free amino and other nitrogen compounds in stored beef muscle

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