Abstract A method for determining the population density of bacterial cells in an environment comprising, 1. separating substantially all nonbacterial cells from an aqueous sample of the environment, for example, by low force centrifugation, 2. separating substantially all bacterial cells from the sample, e.g., by filtration, 3. extracting adenosine triphosphate (hereinafter referred to as ATP) from the bacterial cells, 4. measuring the quantity of ATP present, such as, by reacting the ATP with luciferin and luciferase and measuring the light emitted, and 5. determining the number of bacterial cells in the sample, preferably, by dividing the quantity of ATP, in micrograms, by the average ATP/per cell which was found to be about 5 X 10 10 micrograms.
The method of claim 1 wherein said relationship of quantity of adenosine triphosphate to number of bacterial cells is a constant ratio.
Claim 2
Dependent Claim
23 words
The method of claim 2 wherein said constant ratio has the value of 5 X 10 10 microgram adenosine triphosphate per bacterial cell.
Claim 3
Dependent Claim
26 words
The method of claim 2 wherein substantially all of said bacterial cells are isolated from said suspension by passing said suspension through a bacterial membrane filter.
Claim 4
Dependent Claim
41 words
The method of claim 2 wherein the quantity of said adenosine triphosphate extracted is measured by reacting said adenosine triphosphate with a mixture comprising luciferin and luciferase in the presence of a metal cation and oxygen and measuring the light emitted.
Claim 5
Dependent Claim
11 words
The method of claim 5 wherein said cation is magnesium ion.
Claim 6
Independent Claim
108 words
A method for the determination of the quantity of bacterial cells present in a sample of an aqueous suspension said sample being substantially devoid of interfering nonbacterial cells, said cells being in an unknown growth phase or of unknown species comprising a. separating substantially all bacterial cells from said sample, b. extracting adenosine triphosphate from said separated bacterial cells, c. measuring the quantity of adenosine triphosphate extracted and d. determining the number of bacterial cells in said sample, from the formula X Y/5 X 10 10, where X is the number of said bacterial cells and Y is the quantity of said adenosine triphosphate extracted, measured in micrograms.
Claim 7
Dependent Claim
41 words
The method of claim 7 wherein the quantity of said adenosine triphosphate extracted is measured by reacting said adenosine triphosphate with a mixture comprising luciferin and luciferase in the presence of a metal cation and oxygen and measuring the light emitted.
Claim 8
Dependent Claim
11 words
The method of claim 8 wherein said cation is magnesium ion.