Biased-corrected richness estimates for the Amazonian tree flora

Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come

DNA polymerase delta isolated from <em>Schizosaccharomyces pombe</em> contains five subunits

DNA polymerase delta (pol delta) plays an essential role in DNA replication, repair, and recombination. We have purified pol delta from Schizosaccharomyces pombe more than 10(3)-fold and demonstrated that the polymerase activity of purified S. pombe pol delta is completely dependent on proliferating cell nuclear antigen and replication factor C. SDS/PAGE analysis of the purified fraction indicated that the pol delta complex consists of Five subunits that migrate with apparent molecular masses of 125, 55, 54, 42, and 22 kDa. Western blot analysis indicated that the 125, 55, and 54 kDa proteins are the large catalytic subunit (Pol3), Cdc1, and Cdc37, respectively. The identity of the other two subunits, p42 and p22, was determined following proteolytic digestion and sequence analysis of the resulting peptides. The peptide sequences derived from the p22 subunit indicated that this subunit is identical to Cdm1, previously identified as a multicopy suppressor of the temperature-sensitive cdc1-P13 mutant, whereas peptide sequences derived from the p42 subunit were identical to a previously uncharacterized ORF located on S. pombe chromosome 1.</p