Efficient operation of activated sludge sewage treatment plants requires a rapid, accurate method for determining sludge viable biomass. Bioluminescent assay of microbial adenosine triphosphate (ATP) has been adapted for this purpose. An ATP extraction technique in which diluted sludge was treated with boiling TRIS buffer for 1 min was found to be adequate. ATP, dissolved oxygen (DO) uptake rate, tyrosine, total microscopic cell count, and turbidity were determined in pure cultures. After these tests indicated the applicability of ATP monitoring to activated sludge control, studies were made in a 20-mgd treatment plant. ATP analysis was employed to control mixed liquor biomass through regulation of return sludge. A one-month test period showed good plant performance and revealed close coupling between ATP content and metabolic activity of the sludge.
Preliminary investigation of the application of radiorespirometric technic to protozoan parasites of man indicates a potential for rapid identification. This technic, developed for identification of bacteria, was modified for use with culture forms of Leishmania. Five strains of Leishmania were compared: 2 of L. donovani, 2S and K; L. brasilensis, 2936 and B; and 1 of L. tropica, A. Consisent and rapid (approximately 2 hr) identification was obtained by the radiorespirometric procedure. A computer-type analysis of the radiorespirometric profiles of the 5 strains permitted correct identification of each isolate at the strain level 100% of the time. This technic offers several advantages over many current procedures for identification of protozoan parasites: (A) It is simple, rapid and highly reproducible, (B) Since it does not rely on visual or spectrophotometric determination, it may be conducted in the presence of optically complex substances. (C) It requires relatively low numbers of organisms (approximately 2 x 10(5)/14C-labeled substrate). (D) It is based on differential enzymic activity between species and strains of organisms and therefore, ultimately, on inherent genetic determinates of the parasites. (E) Further development of the procedure and accumulation of a data reference "bank" would allow automation of most of the identification process.
Methods are described for the detection of low numbers of bacteria by monitoring "CO2 evolved from "C-labeled substrates. Cell suspensions are filtered with membrane filters, and the filter is then moistened with 0.1 ml of labeled medium in a small, closed apparatus. Evolved "CO2 is collected with Ba(OH)2-moistened filter pads and assayed with conventional radioactivity counting equipment. The kinetics of "CO2 evolution are shown for several species of bacteria. Fewer than 100 colony-forming units of most species tested were detected in 2 h or less. Bacteria were inoculated into blood and the mixture was treated to lyse the blood cells. The suspension was filtered and the filter was placed in a small volume of labeled medium. The evolved "CO2 was trapped and counted. A key development in the methodology was finding that an aqueous solution of Rhozyme and Triton X-100 produced lysis of blood but was not detrimental to bacteria.
Methods are described for the detection of low numbers of bacteria by monitoring 14 CO 2 evolved from 14 C-labeled substrates. Cell suspensions are filtered with membrane filters, and the filter is then moistened with 0.1 ml of labeled medium in a small, closed apparatus. Evolved 14 CO 2 is collected with Ba(OH) 2 -moistened filter pads and assayed with conventional radioactivity counting equipment. The kinetics of 14 CO 2 evolution are shown for several species of bacteria. Fewer than 100 colony-forming units of most species tested were detected in 2 h or less. Bacteria were inoculated into blood and the mixture was treated to lyse the blood cells. The suspension ws filtered and the filter was placed in a small volume of labeled medium. The evolved 14 CO 2 was trapped and counted. A key development in the methodology was finding that an aqueous solution of Rhyozyme and Triton X-100 produced lysis of blood but was not detrimental to bacteria.
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