Ribosomal RNAs in all organisms are methylated. The functional role of the majority of modified nucleotides is unknown. We systematically questioned the influence of rRNA methylation in Escherichia coli on a number of characteristics of bacterial cells with the help of a set of rRNA methyltransferase (MT) gene knockout strains from the Keio collection. Analysis of ribosomal subunits sedimentation profiles of the knockout strains revealed a surprisingly small number of rRNA MT that significantly affected ribosome assembly. Accumulation of the assembly intermediates was observed only for the rlmE knockout strain whose growth was retarded most significantly among other rRNA MT knockout strains. Accumulation of the 17S rRNA precursor was observed for rsmA (ksgA) knockout cells as well as for cells devoid of functional rsmB and rlmC genes. Significant differences were found among the WT and the majority of rRNA MT knockout strains in their ability to sustain exogenous protein overexpression. While the majority of the rRNA MT knockout strains supported suboptimal reporter gene expression, the strain devoid of the rsmF gene demonstrated a moderate increase in the yield of ectopic gene expression. Comparative 2D protein gel analysis of rRNA MT knockout strains revealed only minor perturbations of the proteome.

High alumina fenites in the Mont Saint Hilaire alkaline complex, Québec, Canada, form bodies at the contact of peralkaline nepheline syenite. Fenites are subdivided into four types: corundum-spessar tine-biotite-feldspar, muscovite-corundum-hercynite-biotite-feldspar, carbonated muscovite-biotitehercynite-feldspar, and spessartine-hercynite-feldspar. Accessory minerals of the ilmenite-pyrophanite series, columbites, zircon, thorite, pyrrhotite, Fe, Mn, Mg, Ca, Ba, and REE carbonates, uedaite (Ce), etc. are identified. Three stages are suggested in the formation of these rocks. In mineralogy and geochemistry, the Mont Saint Hilaire high alumina fenites are similar to Al rich fenites replacing xenoliths in the Khibiny alkaline complex, Russia. In both cases, fenites are related to peralkaline rocks and replace high alumina pro toliths: granite at Mont Saint Hilaire and metapelites in the Khibiny Mountains. These fenites are regarded as a specific type of fenites with rock forming Mg depleted hercynite.

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