Amino acid utilization by L-M strain mouse cells in a chemically defined medium

In Vitro ◽  
1972 ◽  
Vol 7 (5) ◽  
pp. 330-343 ◽  
Author(s):  
Gary D. Stoner ◽  
Donald J. Merchant
Keyword(s):  
Amino Acid ◽  
Defined Medium ◽  
Chemically Defined Medium ◽  
Strain Mouse ◽  
Amino Acid Utilization ◽  
Mouse Cells

QUALITATIVE STUDIES OF SOIL MICROORGANISMS: IX. AMINO ACID REQUIREMENTS OF RHIZOSPHERE BACTERIA

1950 ◽  
Vol 28c (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. H. Wallace ◽  
A. G. Lochhead
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Soil Microorganisms ◽  
Maximum Growth ◽  
Defined Medium ◽  
Chemically Defined Medium ◽  
Special Significance ◽  
Specific Amino Acid ◽  
Pronounced Decrease ◽  
Amino Acid Requirements

A study was made of the more specific amino acid requirements of bacteria from the rhizospheres of clover, flax, and wheat plants for which a chemically defined medium containing 23 amino acids provided essentials for maximum growth. Of seven groups of amino acids, the sulphur-containing group (cysteine, methionine, and taurine) was found to be of special significance, the omission of this group resulting in a pronounced decrease in the percentage of organisms able to develop. Further study of organisms dependent upon this group of amino acids for growth showed methionine to be by far the most essential compound. While evident for bacteria from the rhizosphere of all three crops, the effect was more pronounced in the case of clover than with flax or wheat.

scholarly journals l-Alanine Auxotrophy of Lactobacillus johnsonii as Demonstrated by Physiological, Genomic, and Gene Complementation Approaches

2004 ◽  
Vol 70 (3) ◽  
pp. 1869-1873 ◽  
Author(s):  
Hengameh van der Kaaij ◽  
Frank Desiere ◽  
Beat Mollet ◽  
Jacques-Edouard Germond
Keyword(s):  
Bacillus Subtilis ◽  
Amino Acid ◽  
Genetic Analysis ◽  
Heterologous Expression ◽  
Defined Medium ◽  
Chemically Defined Medium ◽  
Lactobacillus Johnsonii ◽  
Gene Complementation ◽  
Alanine Dehydrogenase ◽  
Comparative Genetic Analysis

ABSTRACT Using a chemically defined medium without l-alanine, Lactobacillus johnsonii was demonstrated to be strictly auxotrophic for that amino acid. A comparative genetic analysis showed that all known genes involved in l-alanine biosynthesis are absent from the genome of L. johnsonii. This auxotrophy was complemented by heterologous expression of the Bacillus subtilis l-alanine dehydrogenase.

A Deficiency in Aspartate Biosynthesis inLactococcus lactis subsp. lactis C2 Causes Slow Milk Coagulation

1998 ◽  
Vol 64 (5) ◽  
pp. 1673-1679 ◽  
Author(s):  
Hua Wang ◽  
Weizhu Yu ◽  
Tim Coolbear ◽  
Dan O’Sullivan ◽  
Larry L. McKay
Keyword(s):  
Carbon Dioxide ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Pyruvate Carboxylase ◽  
Defined Medium ◽  
Transport Systems ◽  
Chemically Defined Medium ◽  
Acid Transport ◽  
Amino Acid Requirements ◽  
Milk Coagulation

ABSTRACT A mutant of fast milk-coagulating (Fmc+)Lactococcus lactis subsp. lactis C2, designatedL. lactis KB4, was identified. Although possessing the known components essential for utilizing casein as a nitrogen source, which include functional proteinase (PrtP) activity and oligopeptide, di- and tripeptide, and amino acid transport systems, KB4 exhibited a slow milk coagulation (Fmc−) phenotype. When the amino acid requirements of L. lactis C2 were compared with those of KB4 by use of a chemically defined medium, it was found that KB4 was unable to grow in the absence of aspartic acid. This aspartic acid requirement could also be met by aspartate-containing peptides. The addition of aspartic acid to milk restored the Fmc+phenotype of KB4. KB4 was found to be defective in pyruvate carboxylase and thus was deficient in the ability to form oxaloacetate and hence aspartic acid from pyruvate and carbon dioxide. The results suggest that when lactococci are propagated in milk, aspartate derived from casein is unable to meet fully the nutritional demands of the lactococci, and they become dependent upon aspartate biosynthesis.

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