Search

Streptococcus pneumoniae synthesizes >100 types of capsular polysaccharides (CPSs). While the diversity of the enzymes and transporters involved is enormous, it is not limitless. In this review, we summarized the recent progress on elucidating the structure–function relationships of CPSs, the mechanisms by which they are synthesized, how their synthesis is regulated, the host immune response against them and the development of novel pneumococcal vaccines. Based on the genetic and structural information available, we generated provisional models of the CPS repeating units that remain unsolved. In addition, to facilitate cross-species comparisons and assignment of glycosyltransferases, we illustrated the biosynthetic pathways of the known CPSs in a standardized format. Studying the intricate steps of pneumococcal CPS assembly promises to provide novel insights for drug and vaccine development as well as improve our understanding of related pathways in other species. [ABSTRACT FROM AUTHOR]

To determine the molecular taxonomic affiliations of small planktonic protists in the northern South China Sea, we constructed phylogenetic trees by correlating the 18S rDNA sequences of known heterotrophic protists with those of unknown protists from four sites. There was a high diversity of these protists in the northern South China Sea that were not sampled by net collection. In addition, we discovered a surprisingly large number of novel radiolarian sequences that showed a unique biogeographic group for this location. Our new data on centrohelids confirmed recent studies showing that representatives of this group live in marine habitats and not only in fresh water. We also report two newly classified eukaryotic lineages (Telonemia and Katablepharidophyta) in the South China Sea for the first time. Furthermore, the phylogenetic relationships showed that the distribution of the novel protists in the northern South China Sea had distinct spatial variation. Our work extends knowledge about the diversity and habitats of planktonic protists in the South China Sea. [ABSTRACT FROM AUTHOR]