Bacterial pathogens employ a variety of survival strategies when they invade eukaryotic cells. The amoeba Dictyostelium discoideum is used as a model host to study the pathogenic mechanisms that Legionella pneumophila, the causative agent of Legionnaire's disease, uses to kill eukaryotic cells. Here we show that the infection of D. discoideum by L. pneumophila results in a decrease in mitochond...

Interrelationships of the tapeworms (Platyhelminthes: Cestoda) were examined by use of small (SSU) and large (LSU) subunit ribosomal DNA sequences and morphological characters. Fifty new complete SSU sequences were added to 21 sequences previously determined, and 71 new LSU (D1-D3) sequences were determined for the complementary set of taxa representing each of the major lineages of cestodes as...

The present edition of large subunit (LSU; 23S and 23S-like) rRNA secondary structures updates and refines the collections of 1988 [1] and 1990 [2]. As in [1] and [2], each LSU rRNA sequence is presented as a secondary structure, a two-dimensional format that represents, in part, the biologically relevant conformation of the rRNA molecule. When LSU rRNA sequences are configured in this manner, ...

The malaria parasite Plasmodium falciparum carries an extrachromosomal 35 kb circular DNA molecule of unknown provenance. A striking feature of the circle is a palindromic sequence of genes for subunit rRNAs and several tRNAs, spanning ca. 10.5 kb. The palindrome has an intriguing resemblance to the inverted repeat of plastid genomes, and the sequence and putative secondary structure of the mal...

Ribosomal RNAs in both prokaryotes and eukaryotes feature numerous repeats of three or more nucleotides with the same nucleobase (homoiterons). In prokaryotes these repeats are much more frequent in thermophile compared to mesophile or psychrophile species, and have similar frequency in both large RNAs. These features point to use of prokaryotic homoiterons in stabilization of both ribosomal su...

Of the three major bilaterian clades, Lophotrochozoa has the greatest diversity and disparity of body forms and is the least understood in terms of phylogenetic history. Within this clade, small nuclear ribosomal subunit (SSU or 18S) studies have failed to provide resolution and other molecular markers have insufficient taxon sampling. To examine relationships within Lophotrochozoa, we collecte...

The recent introduction of molecular techniques in eukaryotic microbial diversity studies, in particular those based in the amplification and sequencing of small-subunit ribosomal DNA (SSU rDNA), has revealed the existence of an unexpected variety of new phylotypes. The taxonomic ascription of the organisms bearing those sequences is generally deduced from phylogenetic analysis. Unfortunately, ...

Because of the high genetic variability of the nuclear-encoded ribosomal RNA genes within single spores of arbuscular mycorrhizal fungi (AMF, Glomeromycota), new alternative marker genes are needed to better resolve closely related taxa. Based on published nucleotide sequences of the mitochondrial large ribosomal subunit (mt-LSU), new fungal-specific primers were constructed and successfully us...

Robert L. Smith, M.D.,∗ Anand Irimpen, M.D.,∗ Frederick R. Helmcke, M.D.,† and Edmund Kenneth Kerut, M.D.‡§ ∗Division of Cardiology, Tulane University School of Medicine, New Orleans, Louisiana, †Department of Medicine, Section of Cardiology, LSU Health Sciences Center, New Orleans, Louisiana, ‡Departments of Pharmacology and Physiology, LSU Health Sciences Center, New Orleans, Louisiana, and ‡...