Acta Microbiologica 19. (1972)
1. szám - Geck, P.–Novák, E. K.: The India-ink Immuno-reaction as a New Method for the Rapid Diagnosis of Yeast Strains
GECK and NOVÁK Materials and methods The procedures used for the production of rabbit immune sera, cultivation of the strains, preparation of smears were the same as in our earlier study [3]. The India-ink immuno-reaction has been carried out according to Geck [1, 2] as follows. (a) Smears of 48-hour cultures of adequate yeast strains were dried and fixed with heat. (b) One drop of liquid India-ink (“Holló” Chinese India-ink, Politur és Vegyi Termékek Gyára, Budapest) was mounted on the smears with one drop of an adequate dilution of an anti-Pc. albicans rabbit immune serum, then mixed with a wire-loop and incubated in a moist chamber at room temperature for 5 minutes. (c) Following the incubation period the smears were washed in isotonic NaCl solution mixed with tap water (400 -f- 600 ml), under medium pressure by means of a ball pipette. Direct evaluation of the method and the photomicrographs were performed with a Zeiss NfpK microscope at about 600 X magnification. The basis of the evaluation was the following arbitrary scale (see also Table I and Fig. 1): — only the light greenish-grey contour of the cells is visible; + the cells are hardly visible, aggregates of India-ink as scattered black spots on the cell wall can be observed; -f- an interrupted black India-ink deposit covers the wall of the cells; -j-+ a thin continuous black coat covers the wall of the cells, within the contour of the India-ink deposit the cell is greyish-white in colour; -f- + -b the wall of the cells has an intensive black contour because of the India-ink deposit, the cell itself is greyish-brown in colour; —1—I—I—the wall of the cells appears as a broad intensive black contour, the cell is deep brown in colour. Results and discussion On the basis of literary data [9] and our own study [3] ten species have been selected for the evaluation of the method. These species were partly related serologically to Pc. albicans, partly unrelated ones. The results are summarized in Table I. Table I India-ink immuno-reaction carried out with different dilutions of an anti-Pc. albicans 360/1960 rabbit immune serum and different yeast strains Species and designation Serum dilution of strains 1 :5 1 : 10 1 : 20 1 : 40 1 : 80 1 : 160 1 : 320 Pc. albicans 85/1957 Pc. tropicalis+ +++ ++++ + + + + +++ + + + + + +++ 302/1964 Pc. stellatoidea ++ + + ++++ + + + + ++ + + ++ — 29-64 + + + + + + + + —1----J----1-+++ + — C. beverwijkii 478/1961 S. cerevisiae ++++ ++++ + + + + 4-± ± - CXCII/1967+ +++ ++++ + ++ + + — C. reukaufii 405+ ++ ++ + ++ + + — N. slovaca 771+ + — — — — C. utilis 287/1964+ Pc. = Procandida; C. = Candida; S. = Saccharomyces ; N. = Nadsonia, the synonym of C. humicola (Lodder 1970) Acta Microbiologica Academiae Scientiarum Hungaricae 19, 1972