Genetics and physiology of Aspergillus / edited by John E. Smith and John A. Pateman.

Date:
1977
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Genetics and physiology of Aspergillus / edited by John E. Smith and John A. Pateman. Source: Wellcome Collection.

    19/572 (page 5)
    ASPERGILLUS TAXONOMY 5 showed less intraspecific similarity than interspecific similarity; this suggested to the authors that some strains of Л might be more closely related to other Д. group members or to other groups of fungi than they are to one another. The inter- group similarity between these 12 strains of the Л .^Z-aMCM^roup was compared to A, flavus group speces. kga-ixi, A .pcœasit'icus was unique, showing characters in common with strains of the A.glauous group. Strangely, in intergeneric comparisons of composite pyrolysis profiles of conidia from n\r\e РепъсъЪЪгит species of the Asymmetrica- Fasciculata with those from members of the A. fZavus group, A. parasït-icus showed a somehwat higher similarity value to the nine РепгсгЪЪгит spp. than to the other three species in the flavus group (Kulik & Vincent, 1973). Although reproducibility of pyrolysis profiles has been demon¬ strated for the bacteria (Reiner, 1967), nonreproducibility of pyrograms of fungi has plagued investigators (Carmichael, Sekhon & Sigler, 1973; Sekhon & Carmichael, 1971, 1972; Burns, Stretton & Jayatilake, 1976). Variation between replicates is often as great as between species. Apparently homogeneity is more readily achieved in a bacterial population than in fungi where physiological age of different portions of the mycelium varies. It is regrettable that difficulties encountered and time con¬ sumed in application of PGLC to fungal taxonomy so limits the number of strains included in any one study that results of the investi¬ gation are of questionable value. If reproducibility is so elus¬ ive with single strains of a single species, within a single lab and using the same apparatus, is there hope for comparing results between laboratories? Will there ever be a vast body of information collated from all investigations that will yield information useful for automated taxonomy? Could it be that the term 'fingerprinting by PGLC' is more apt than intended — that every strain of every species of every genus will be as unique as in Homo sapïens? Nucleic Acids Molecular analysis of the genetic code can be approximated by analysis of nuclear DNA. Determination of the relative proportions of the four bases: adenine, thymine, guanine, and cytosine, and their order in the DNA strand are of potential taxonomic importance. DNA homology analysis has been applied with impressive success to taxonomic problems in bacteria CDeLey, 1968) , but until very recently little application has been made to taxonomy of the fungi. Storck, with various colleagues, has been most actively engaged in the study of RNA and the various DNAs of fungi as they relate to taxonomy and phylogeny. In 1965, he reported guanine and cystine