Comparative analysis of ribonuclease P RNA of the planctomycetes.

The planctomycetes, order Planctomycetales, are a distinct phylum of domain Bacteria. Genes encoding the RNA portion of ribonuclease P (RNase P) of some planctomycete members were sequenced and compared with existing database planctomycete sequences. rnpB gene sequences encoding RNase P RNA were generated by a conserved primer PCR strategy for Planctomyces brasiliensis, Planctomyces limnophilus, Pirellula marina, Pirellula staleyi strain ATCC 35122, Isosphaera pallida, one other Isosphaera strain, Gemmata obscuriglobus and three other strains of the Gemmata group.

Gene discovery within the planctomycete division of the domain Bacteria using sequence tags from genomic DNA libraries.

Background: The planctomycetes comprise a distinct group of the domain Bacteria, forming a separate division by phylogenetic analysis. The organization of their cells into membrane-defined compartments including membrane-bounded nucleoids, their budding reproduction and complete absence of peptidoglycan distinguish them from most other Bacteria. A random sequencing approach was applied to the genomes of two planctomycete species, Gemmata obscuriglobus and Pirellula marina, to discover genes relevant to their cell biology and physiology.

Cell compartmentalisation in planctomycetes: novel types of structural organisation for the bacterial cell.

The organisation of cells of the planctomycete species Pirellula marina, Isosphaera pallida, Gemmata obscuriglobus, Planctomyces maris and "Candidatus Brocadia anammoxidans" was investigated based on ultrastructure derived from thin-sections of cryosubstituted cells, freeze-fracture replicas, and in the case of Gemmata obscuriglobus and Pirellula marina, computer-aided 3-D reconstructions from serial sections of cryosubstituted cells. All planctomycete cells display a peripheral ribosome-free region, termed here the paryphoplasm, surrounding the perimeter of the cell, and an interior region including any nucleoid regions as well as ribosome-like particles, bounded by a single intracytoplasmic membrane (ICM), and termed the pirellulosome in Pirellula species. Immunogold labelling and RNase-gold cytochemistry indicates that in planctomycetes all the cell DNA is contained wholly within the interior region bounded by the ICM, and the paryphoplasm contains no DNA but at least some of the cell's RNA.

Phylogenetic analysis of evolutionary relationships of the planctomycete division of the domain bacteria based on amino acid sequences of elongation factor Tu.

Sequences from the tuf gene coding for the elongation factor EF-Tu were amplified and sequenced from the genomic DNA of Pirellula marina and Isosphaera pallida, two species of bacteria within the order Planctomycetales. A near-complete (1140-bp) sequence was obtained from Pi. marina and a partial (759-bp) sequence was obtained for I.

PSEUDONEOCHLORIS MARINA (CHLOROPHYTA), A NEW COCCOID ULVOPHYCEAN ALGA, AND ITS PHYLOGENETIC POSITION INFERRED FROM MORPHOLOGICAL AND MOLECULAR DATA.

Ultrastructural and molecular sequence data were used to assess the phylogenetic position of the coccoid green alga deposited in the culture collection of the University of Texas at Austin under the name of Neochloris sp. (1445). This alga has uninucleate vegetative cells and a parietal chloroplast with pyrenoids; it reproduces by forming naked biflagellate zoospores.

Pirellulosomes: a new type of membrane-bounded cell compartment in planctomycete bacteria of the genus .

A distinct type of cellular organization was found in two species of the planctomycete genus and . Both species possess two distinct regions within the cell which are separated by a single membrane. The major region of the cell, the pirellulosome, contains the fibrillar condensed nucleoid.