CONTINUOUS CULTURE OF BRUCELLA ABORTUS S.19

1961 ◽  
Vol 7 (4) ◽  
pp. 491-505 ◽  
Author(s):  
Andreas H. W. Hauschild ◽  
Hilliard Pivnick
Keyword(s):  
Growth Rate ◽  
Continuous Culture ◽  
Dilution Rate ◽  
Brucella Abortus ◽  
Specific Growth ◽  
Limiting Factor ◽  
Continuous Growth ◽  
Viable Cells ◽  
Metabolic Products ◽  
Growth Of Bacteria

An apparatus is described for the continuous growth of bacteria. Brucella abortus S.19 has been grown in continuous culture for periods up to 3 weeks with populations up to 2 × 1011viable cells per ml and without the establishment of nonsmooth variants.Concentrations between 3 × 109and 2 × 1011cells per ml could be maintained as a function of the dilution rate without the requirement of a known limiting factor in the medium. In a series of steady-state conditions, the specific growth rate increased steadily up to 0.28 hour−1with decreasing population levels.Incidence of mutants was governed by the dilution rate and could also be reduced by various chelating substances.In continuous growth combined with continuous dialysis, population levels were approximately twice those obtained in continuous growth without dialysis. The effect of dialysis appears to be the continuous removal of growth-limiting metabolic products.

Evolution of Escherichia coli During Growth in a Constant Environment

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 349-358
Author(s):  
Robert B Helling ◽  
Christopher N Vargas ◽  
Julian Adams
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Continuous Culture ◽  
Specific Growth ◽  
Maximum Specific Growth Rate ◽  
Constant Environment ◽  
Single Clone ◽  
Mixed Populations

ABSTRACT Populations of Escherichia coli, initiated with a single clone and maintained for long periods in glucose-limited continuous culture, developed extensive polymorphisms. In one population, examined after 765 generations, two majority and two minority types were identified. Stable mixed populations were reestablished from the isolated strains. Factors involved in the development of this polymorphism included differences in the maximum specific growth rate and in the transport of glucose, and excretion of metabolites by some clones which were utilized by minority clones.

Effect of carbon dioxide on growth of Pseudomonas putida ATCC 11172 on asparagine, citrate, glucose, and lactate in batch and continuous culture

1985 ◽  
Vol 31 (9) ◽  
pp. 763-766 ◽  
Author(s):  
Göran Molin
Keyword(s):  
Carbon Dioxide ◽  
Growth Rate ◽  
Pseudomonas Putida ◽  
Continuous Culture ◽  
Specific Growth ◽  
Carbon Sources ◽  
Maximum Specific Growth Rate ◽  
The Other ◽  
Continuous Cultures ◽  
Batch Cultures

The growth of Pseudomonas putida ATCC 11172 on L-asparagine, citrate, D-glucose, and L-lactate was followed in air and in 40% CO2 + air, using batch and carbon-limited continuous cultures. Batch cultures in air utilized a mixture of the carbon sources simultaneously. However, a change to 40% CO2 favoured the utilization of glucose. The maximum specific growth rate (μmax) in air was about 0.3 h−1 on glucose and 0.6 h−1 on the other carbon sources. In CO2, the μmax for glucose was reduced by 16% compared with almost 60–70% for the others. An order of preference for the different carbon sources in continuous cultures was determined by comparing the dilution rates at which the different carbon sources started to appear in the effluent. Glucose was the first compound to appear as the dilution rate increased (lowest preference when grown in air). In 40% CO2, the μmax for glucose was slightly higher than the others and the recorded preference for glucose in continuous culture was equal to that for citrate but was somewhat lower than that of lactate and asparagine. D-Gluconate and glucono-δ-lactone were produced as a step in the utilization of glucose. The D-gluconate production was enhanced by CO2.

Growth studies on the lactic streptococci: III. Observations on continuous growth behaviour in reconstituted skim-milk

1972 ◽  
Vol 39 (1) ◽  
pp. 151-159 ◽  
Author(s):  
A. R. Keen
Keyword(s):  
Hydrogen Peroxide ◽  
Growth Rate ◽  
Dilution Rate ◽  
Skim Milk ◽  
Oxygen Toxicity ◽  
Soluble Nitrogen ◽  
Continuous Growth ◽  
Streptococcus Lactis ◽  
Ph Range ◽  
Specific Growth Rates

SummaryThe behaviour ofStreptococcus cremorisAM1and AM2, andStreptococcus lactisML8in continuous growth in reconstituted skim-milk medium under controlled conditions of pH has been investigated.At 20°C under aerobic conditions small quantities of oxygen were found to stimulate the growth rate ofStr. lactisML8between pH 5·05 and 5·45. Growth between pH 5·45 and 6·35 became erratic due to the accumulation of hydrogen peroxide. Above pH 6·35 hydrogen peroxide could not be detected in the continuously growing culture and below pH 5·05 the growth rate of the culture was not affected by small quantities of oxygen. An effect of direct oxygen toxicity on growth, distinct from that of hydrogen peroxide accumulation, was observed over the limited pH range investigated. After 48 h growth in the presence of small concentrations of oxygen the effect disappeared.At 30°C under anaerobic conditions a region in the dilution rate curves was observed withStr. cremorisAM1and AM2andStr. lactisML8which suggested the occurrence of a growth-limiting component. This region of slow growth could be correlated with diminished soluble nitrogen values, and was eliminated by enrichment of the medium with soluble nitrogen.An unusual feature of the investigation was the dilution rates, indicative of extremely fast specific growth rates, experienced forStr. lactisML8. It was thought unlikely that wall growth contributed appreciably to the dilution rate as a similar phenomenon was not observed withStr. cremorisAM1or AM2.

Growth Rate of Young Sockeye Salmon, Oncorhynchus nerka, in Relation to Fish Size and Ration Level

1975 ◽  
Vol 32 (11) ◽  
pp. 2103-2110 ◽  
Author(s):  
J. R. Brett ◽  
J. E. Shelbourn
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Sockeye Salmon ◽  
Specific Growth ◽  
Oncorhynchus Nerka ◽  
Limiting Factor ◽  
Fish Size ◽  
Ration Level ◽  
The Family ◽  
Constant Growth

The specific growth rate of young sockeye salmon (Oncorhynchus nerka) was studied for a period of 7 mo to determine the effect of body weight when on restricted and unrestricted rations. It was hypothesized that a restricted ration would result in a fixed growth rate until size became a limiting factor reducing food demand below the prescribed level and thereby reducing growth rate. The results support the hypothesis, with the possible exception that growth rate may increase slightly during the period of fixed ration. On excess ration the specific growth rate fell from 3.6% weight per day (2.4 g mean weight) to 1.0% weight per day (37 g mean weight); intermediate constant growth rates accompanied the periods of fixed ration, inflecting to lower rates subsequently. The general equation log G = a + b log W (where G = specific growth rate, and W = weight in grams) was found to apply to a number of salmonids. The slope value of b = −0.4 ±.04 appears to characterize the family, with the intercept a taking on different values according to the varying capacity for rapid growth.

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