Biomedical subjects

P A Blanz

Publications and source records attributed to P A Blanz.

4 recordsLinked to original sources

PubMed1993

The higher fungus Protomyces inouyei has two group I introns in the 18S rRNA gene.

The nucleotide sequence of the small-subunit rRNA (18S rRNA) coding gene in the higher fungus Protomyces inouyei contains two group I introns. This is the first report of two group I introns in the 18S rRNA coding region. Based on the comparison of the two introns of Protomyces inouyei with those of the green alga Ankistrodesmus stipitatus, and the other two higher fungi Pneumocystis carinii and Ustilago maydis, the Protomyces introns are group I introns containing the highly conserved sequence elements P, Q, R, and S. Intron A of Protomyces inouyei is located in the same position as in Pneumocystis carinii while intron B shares the location with that in Ustilago maydis. The phylogenetic relationships strongly support horizontal transfer of these group I introns.

Ascomycota↗

PubMed1989

Group-specific differences in the secondary structure of the 28S ribosomal RNA of yeasts.

Ribosomal RNA (rRNA) sequences represent a good taxonomic character. Even small but significant parts of rRNA molecules can be used as a basis for taxonomic conclusions. A highly variable region within the 28S ribosomal nucleotide sequences from various yeasts was analysed. Despite numerous nucleotide exchanges in this region the secondary structure is generally conserved as in helices 17.1 and 17.2. However, among the organisms analysed the basidiomycetous yeasts show an insertion of 30 nucleotides which is missing in other yeasts. In this feature the Taphrinales and Schizosaccharomycetaceae resemble the 28S rRNA of Saccharomyces carlsbergensis rather than that of the basidiomycetous yeasts. Optimal sequence alignment and a good understanding of the secondary structure is an indispensible prerequisite for any evaluation of the taxonomic significance of differences in ribosomal RNA nucleotide sequences.

Base Sequence↗

PubMed1986

A computer program for comparative analysis of nucleic acid sequences.

The programs offer the possibility of comparing pairs of homologous sequences in order to find out percentage of homology, number of identical and deviating nucleotides, of transitions and transversions and, derived from these, KNUC-values according to Kimura (1) and the corresponding standard error sigmaK. The sequences can be printed in pairs underneath each other, homologies are indicated by asterisks between the identical nucleotides. Out of a set of homologous sequences stored on a disk any number of sequences can be compared in pairs in this way, and a matrix containing either the percentage of homology values, the number of deviating nucleotides or the KNUC-values together with the corresponding standard errors can be sent to screen, printer or disk. A program will be available soon which creates a dendrogram representing the similarity between the sequences by use of an average linkage clustering method deduced from this matrix. The programs are written for Apple II computers using UCSD-PASCAL and for Sirius I/Victor 9000 computers using TURBO-PASCAL.

Base Sequence↗

PubMed1984

Highly conserved 5S ribosomal RNA sequences in four rust fungi and atypical 5S rRNA secondary structure in Microstroma juglandis.

The 5S ribosomal RNA nucleotide sequences of five basidiomycetous fungi, Coleosporium tussilaginis , Gymnosporangium clavariaeforme , Puccinia poarum , Endophyllum sempervivi and Microstroma juglandis were determined. Despite high differentiation in their host spectra the four rust species are highly conserved with respect to their 5S rRna sequences, which fit with the basidiomycete cluster 5 described by Walker and Doolittle (1). The sequences obtained from the first three rust fungi were proven to be identical while the sequence from Endophyllum sempervivi showed two base substitutions compared with the other rust fungi. The Microstroma juglandis 5S rRNA sequence differs from all other basidiomycete 5S rRNA sequences published so far in respect to its secondary structure which shows an atypical 'CCA' loop in helix D, but it reveals typical basidiomycetous signature nucleotides. Therefore Microstroma juglandis represents a cluster of its own within the Basidiomycetes. A dendrogram was constructed based on Kimura's "Neutral Theory of Molecular Evolution".

Base Sequence↗