Comparison between the organization of nuclear ribosomal DNA unit of Euglena gracilis Z and var. Bacillaris

Abstract

We have characterized the nuclear rDNA unit of Euglena gracilis var. bacillaris and compared it to that of the Z strain. We have localized restriction sites for Eco R1, Sal 1, Sma 1, Hind III, Bam H1 and Bgl II on this unit as well as the coding region for 20 S and 25 S rRNAs. For both strains, results suggest an homogeneity of the 11.6 kbp rDNA units. Comparison between strains shows differences characterized by two additional Sal 1 sites in bacillaris and the likely methylation of one Sma 1 site in Z. Both differences are localized in a non-coding region of the rDNA unit. Analyses of 18 Euglena strains from various origins confirm these differences and allow easy recognition of bacillaris and Z type strains.

Discrimination of Euglena gracilis strains Z and bacillaris by MALDI-TOF MS

“…However, the differences in chloroplast genomes cannot be used for identification of white mutants or assigning a white mutant to its ancestral strain. The discrimination of E. gracilis strains Z and bacillaris , and their white mutants is thus often limited to time‐consuming old‐fashioned molecular techniques such as the analysis of restriction sites in nuclear rDNA operons (Neyret‐Djossou et al, 1986; Nicolas & Russell, 1988).…”

“…However, the differences in chloroplast genomes cannot be used for identification of white mutants or assigning a white mutant to its ancestral strain. The discrimination of E. gracilis strains Z and bacillaris, and their white mutants is thus often limited to time-consuming old-fashioned molecular techniques such as the analysis of restriction sites in nuclear rDNA operons (Neyret-Djossou et al, 1986;Nicolas & Russell, 1988). All these disadvantages can be overcome by MALDI-TOF MS analysis, which has been already presented as a suitable alternative for microalgae characterization (Barbano et al, 2015;Emami et al, 2015;Wirth et al, 2012).…”

Nuclear rDNA inEuglena gracilis: paucity of chromosomal units and replication of extrachromosomal units

“…Purified chromosomal DNA was analysed for rDNA gene dosage by dot blot hybridization. The probe used covers the entire rDNA unit (9,11). rDNA inserts were excised and purified from the vector.…”