CABI

About: CABI is a nonprofit organization based out in Wallingford, United Kingdom. It is known for research contribution in the topics: Population & Introduced species. The organization has 789 authors who have published 1759 publications receiving 73843 citations. The organization is also known as: Centre for Biosciences and Agriculture International.

A reappraisal of the terverticillate penicillia using biochemical, physiological and morphological features. III. An evaluation of pectinase and amylase isoenzymes for species characterization.

Abstract: Summary: Polyacrylamide gel electrophoresis of extracellular pectinase and amylase isozymes of 170 mainly terverticillate Penicillium strains was undertaken. The data were coded and subjected to numerical analysis. Variation in intensity of isozymes was observed in repeat analyses of some strains, although most were consistent. Variation was also observed between some representative strains of species. P. viridicatum was more variable than P. brevicompactum and P. hordei for intensity of pectinase activity. There was a correlation between the grouping of the strains on the basis of the isozymes and the species concepts only in some cases. The method proved useful for the identification of strains producing intense activity which provided clear patterns, for example, P. brevicompactum and P. chrysogenum and to a lesser extent P. solitum var. crustosum and P. hordei. The method was also exclusionary in that some species were restricted to a particular cluster or subcluster. Amylase patterns confirmed that strains referred to as single species are not all homogeneous genetically, and that some strains are not simply haploid homokaryons. The genetic heterogeneity of the strains explains some of the problems in the systematics of the terverticillate penicillia.

Comparison of rRNA genotype frequencies of Parmelia sulcata from long established and recolonizing sites following sulphur dioxide amelioration

Abstract: The variable internally transcribed spacer (ITS) regions of the rRNA gene cluster, and the termini of the large and small subunit genes, were amplified from 231 specimens of the lichen-forming fungusParmelia sulcata from the UK and Spain. Amplification products comprised three distinct size groups of 580, 622 and 835 base pairs (bp). Analyses of the collections from England, Wales and central Spain established the 622 bp genotype as the most widespread, and the 835 bp genotype as the next most frequent. The size difference was due to a group I intron at the 3′ end of the small subunit. The relative frequencies of the three genotypes were consistent between long established sites in Spain and the UK. The frequencies of the different size classes were examined in the vegetatively reproducing populations recolonizing following the amelioration of sulphur dioxide air pollution. Populations ofP. sulcata from long established sites where sulphur dioxide levels are known to have risen and then fallen contained two genotypes. Populations from recolonising sites whereP. sulcata had previously been lost consisted of a single genotype (622bp). This technology provides a powerful tool for testing hypotheses relating to the individuality and population structure of lichens, and has implications for lichen conservation.