Improvements in devices for the study of the fermentative characteristics of living cells

摘要

PICT:1006774/C6-C7/1 PICT:1006774/C6-C7/2 A device for detecting the fermentative action of living cells on chemical substances consists of two portions or discs 111, 112, Figs. 4 and 5, of absorbent material in contact with each other, the first disc 111 containing in the dried state a chemical substance which, under the fermentative action of a given species of living cells, will yield detectable degradation products while the second disc 112 forms a hydratable support for the diffusion of the degradation products, and an air- and water-tight layer 113 disposed on the discs so as to cover in part the upper side of the second disc 112 and wholly or partly the upper side of the first disc 111. The first disc preferably also contains in the dried state an indicating reagent e.g. a colour indicator adapted to detect the degradation products arising from the chemical substance and species of living cells. The discs may be assembled in juxtaposition along a common secant; with this arrangement they may be cut as a single piece from the same sheet of absorbent material. The second disc may be formed of highly absorbent material capable of retaining a sufficient quantity of liquid for dissolving the chemical substance contained in the first disc and for permitting diffusion of the living cells into the second disc without the need for a separate hydrating supporting medium such as agar-agar. The discs of one or more devices are covered and held by a strip or film 113 of cellulose acetate or polyvinyl chloride. In use the device may be disposed in a Petri box on a layer of agar-agar on which a suspension of the living cells has previously been disposed or provided the second disc is highly absorbent, droplets of a suspension of the living cells may be deposited directly on the uncovered surface of the second disc.