Transmembrane molecules for phylogenetic analyses of pathogenic protists: Leishmania-specific informative sites in hydrophilic loops of trans- endoplasmic reticulum N-acetylglucosamine-1-phosphate transferase.

A sequence database was created for the Leishmania N-acetylglucosamine-1-phosphate transferase (nagt) gene from 193 independent isolates. PCR products of this single-copy gene were analyzed for restriction fragment length polymorphism based on seven nagt sequences initially available. We subsequently sequenced 77 samples and found 19 new variants (genotypes).

The usher N terminus is the initial targeting site for chaperone-subunit complexes and participates in subsequent pilus biogenesis events.

Pilus biogenesis on the surface of uropathogenic Escherichia coli requires the chaperone/usher pathway, a terminal branch of the general secretory pathway. In this pathway, periplasmic chaperone-subunit complexes target an outer membrane (OM) usher for subunit assembly into pili and secretion to the cell surface. The molecular mechanisms of protein secretion across the OM are not well understood.

Genome sequence of the endocellular obligate symbiont of tsetse flies, Wigglesworthia glossinidia.

Many insects that rely on a single food source throughout their developmental cycle harbor beneficial microbes that provide nutrients absent from their restricted diet. Tsetse flies, the vectors of African trypanosomes, feed exclusively on blood and rely on one such intracellular microbe for nutritional provisioning and fecundity. As a result of co-evolution with hosts over millions of years, these mutualists have lost the ability to survive outside the sheltered environment of their host insect cells.