The Activity of Chemotherapeutic Agents

Libby, Raymond L.

doi:10.1128/jb.40.5.733-745.1940

Cited by 9 publications

(5 citation statements)

References 10 publications

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“…In contrast to the above studies Libby (1940) reported that using large inocula (12 to 50 million organisms), in every instance where a drug has shown activity at the four-hour incubation period it has been possible to demonstrate activity at the two-hour incubation period. In all our experiments the initial inoculum has been over a billion organisms.…”

Section: Discussionmentioning

confidence: 76%

The Respiration of Streptococcus pyogenes

Sevag

Shelburne

1942

Journal of Bacteriology

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Section: Discussionmentioning

confidence: 76%

The Respiration of Streptococcus pyogenes

Sevag

Shelburne

1942

Journal of Bacteriology

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“…There are, however, a few contrary reports. Libby (1940) used an actively growing culture of a pneumococcus as an inoculum and obtained no delay in the SA action. Muir et al (1942) obtained a delay in the sulfonamide inhibition when using a 24-hour culture of Salmonella enteritidis as an inoculum.…”

Section: Discussionmentioning

confidence: 99%

“…Turbidity readings. Many investigators (Libby, 1940;Kohn and Harris, 1941; MacLeod and Mirich, 1942) have used this method for measuring bacterial growth. Hershey (1939) found that density readings are an accurate method for the determination of growth since nitrogen determinations were proportional to the turbidity readings.…”

Section: Downloaded Frommentioning

confidence: 99%

The Relationship of the Age of the Bacterial Culture to the Delay in Sulfonamide Bacteriostasis

Youmans

1948

J Bacteriol

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The information on the influence of the age of the bacterial culture on the inhibition of bacteria by the sulfonamides is limited and contradictory. Fisher and Armstrong (1947), using as young cells a 16-hour culture of Escherichia coli and as old cells a 22-hour culture, found the young cells were more susceptible to the action of sulfathiazole. Chain et al. (1945), Muir et al. (1942), and Rose and Fox (1942) also believed young cells were more sensitive to the bacteriostatic action of the sulfonamides. Wolff and Julius (1939) reported that the age of the culture was of no importance in the mechanism of sulfonamide inhibition, but Long and Bliss (1939) and Finklestone-Sayliss et al. (1937) indicated that old cells were more sensitive than young cells. Many investigators

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“…This study is concerned with comparing results using the special apparatus described with those obtained with the Klett-Summerson colorimeter, and is not an attempt to establish the value of the turbidimetric method. The latter is something which must be determined by the experimenter for his every individual problem, because results published by various workers comparing the turbidimetric method with other methods such as the plate count have varied considerably (Kohn and Harris, 1941;Libby, 1940). In any particular problem it is mandatory that the method used in determining cell populations give sufficiently accurate results for the interpretations which are to be based upon them.…”

Section: Methodsmentioning

confidence: 99%

A Turbidimetric Method of Following Cell Multiplication within Warburg Flasks

Henry

1945

J Bacteriol

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Recent trends in research employing multiplying cells like bacteria and yeast have led to the use of respirometers such as the Warburg. Experiments are frequently made with cell inhibitors so that a correlation is sought between inhibition of respiration coincident with inhibition of multiplication. The inhibition of respiration can easily be followed by taking periodic manometer readings during the course of the experiment and comparing respiratory values of the inhibited cells with those of the controls. Following the inhibition of division is not so simple, since all the various methods for estimating cell population available so far require opening the particular manometer, thus removing that particular manometer from the experiment. The methods available include chamber count, plate count, dilution count, and turbidimetric measurement.In order to correlate inhibition of respiration with inhibition of division over a period of time, or in fact to determine either one alone in any single instance, it is prerequisite to know with some degree of accuracy the growth curves for the cell population during the period for which the inhibition is to be calculated. This has required running as many manometers for each inhibitor concentration or control as there are to be points on the growth curve. For example, if five points are desired to construct the curve, five manometers must be started, one being removed from the experiment at each time interval and the cell population determined by one of the above-mentioned methods. This usually makes experiments difficult because of the large number of manometers required if several inhibitor concentrations are run simultaneously. Furthermore, a definite error is introduced when the respiration and division are not correlated for the identical cell population. This paper describes a turbidimetric method of following the multiplication of a cell suspension within a respirometer flask, thus circumventing the particular difficulties described above. APPARATUSThe special flask was made from an ordinary Warburg flask having a single side arm. The side arm was removed and replaced by a short length of glass tubing shrunk on a square steel rod;' the end was then sealed off (figure 1).The turbidimeter was constructed by building a Bradley 20 B barrier layer cell into a small unit as shown in figure 2.Sufficient sensitivity for turbidity measurements can only be obtained if aThere is no reason why this side arm should not be round. 31on August 5, 2020 by guest

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The Activity of Chemotherapeutic Agents

Cited by 9 publications

References 10 publications

The Respiration of Streptococcus pyogenes

The Respiration of Streptococcus pyogenes

The Relationship of the Age of the Bacterial Culture to the Delay in Sulfonamide Bacteriostasis

A Turbidimetric Method of Following Cell Multiplication within Warburg Flasks

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