The influence of larval crowding on the development time of populations of Drosophila melanogaster on chemically defined medium

1968 ◽  
Vol 46 (3) ◽  
pp. 493-497 ◽  
Author(s):  
Barrie Cohen
Keyword(s):  
Drosophila Melanogaster ◽  
Amino Acid ◽  
Acid Medium ◽  
Initial Density ◽  
Defined Medium ◽  
Chemically Defined Medium ◽  
Complex Situation ◽  
Insect Populations ◽  
Larval Crowding ◽  
New Formula

Work with Drosophila melanogaster, cultured on chemically defined amino acid medium, showed that at extreme larval densities the average time to pupation and eclosion of the survivors of the insect population is a decreasing function of the initial density. Evidence is presented which illustrates that at extreme densities larval development rate is significantly increased. Possible causes of this phenomenon are cited. It is stressed, however, that a very complex situation exists and more experimentation, particularly biochemical analysis, will be necessary to arrive at the proper causative factors. A new formula is presented for a chemically defined medium for Drosophila melanogaster, and detailed methods of preparation given. The new formula will support an estimated 200 larvae through complete development to adult flies on 5 ml of medium. It is thought that the system utilizing the development of Drosophila melanogaster on chemically defined amino acid medium is a fundamental one for the experimental analysis of developing insect populations.

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.

scholarly journals A chemically-defined growth medium to support Lactobacillus-Acetobacter community analysis

2021 ◽  
Author(s):  
Kevin Aumiller ◽  
Eric Stevens ◽  
Robert Scheffler ◽  
Zehra Tuzun Guvener ◽  
Emily Tung ◽  
...  
Keyword(s):  
Amino Acids ◽  
Drosophila Melanogaster ◽  
Community Analysis ◽  
Defined Medium ◽  
Chemically Defined Medium ◽  
It Support ◽  
Metabolic Interactions ◽  
Commercially Important ◽  
Casamino Acids ◽  
Stock Solutions

Lactobacilli and acetobacters are commercially important bacteria that often form communities in natural fermentations, including food preparations, spoilage, and in the digestive tract of Drosophila melanogaster fruit flies. Communities of these bacteria are widespread and prolific, despite numerous strain-specific auxotrophies, suggesting they have evolved nutrient interdependencies that regulate their growths. The use of a chemically-defined medium (CDM) supporting the growth of both groups of bacteria would greatly facilitate identification of the precise metabolic interactions between these two groups of bacteria. While numerous such media have been developed that support specific strains of lactobacilli and acetobacters, there has not been a medium formulated to support both genera. We developed such a medium, based on a previous Lactobacillus CDM, by modifying the nutrient abundances to improve growth of both groups of bacteria. We further simplified the medium by substituting casamino acids for individual amino acids and the standard Wolfe's vitamins and mineral stocks for individual vitamins and minerals, resulting in a reduction from 40 to 8 stock solutions. The new CDM and variations of it support robust growth of lactobacilli and acetobacters. We provide the composition and an example of its use to measure nutritional interactions.

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