Intra- and intergeneric mating behaviour of ascosporogenous yeasts I. Quantitative analysis of sexual agglutination<xref ref-type="fn" rid="fn1"><sup>1</sup></xref>

Abstract

When respective opposite mating types of the heterothallic yeasts are mixed, remarkable sexual agglutination occurs. This is considered to be indispensable for the subsequent cell fusion and karyogamy. Based on the Duysens's findings (1956) that the heterogeneous distribution or localization of pigment in particles caused to flatten their absorption spectrum, we developed the following equation to express the intensity of agglutination: I/flattening coefficient (designated agglutination index, A.I.)=I-e-k(R--r)k(R-r) expresses mean value of aggregate radii as a parameter to express agglutination intensity. The A.I. is easily measurable with a spectrophotometer. The best fit of k with the experimental values was calculated with a computer. The other parameter to express the intensity of agglutination, mean cell number per aggregate (N¯), was roughly estimated by the equation, N-=(4/3)πR3-/(4/3)πT3=(R-/r)3 The analysis of this parameter supported the above relationship between A.I. and R-⁠. The approximations of the relationship between A.I. and R- are also presented and their validity is discussed.