Phylogenetic placement and lectotypification of Pseudotryblidium neesii (Helotiales, Leotiomycetes)

A phylogenetic analysis of combined rDNA LSU and ITS sequence data was carried out to determine the phylogenetic placement of specimens identified as Pseudotryblidium neesii. The species forms a distinct clade within Dermateaceae (Helotiales, Leotiomycetes) with Rhizodermea veluwiensis and two Dermea species. The geographical distribution of this species, previously known only from Europe on Abies alba, is extended to north-western North America where it grows exclusively on A. grandis. The name P. neesii is lectotypified in order to disentangle the complicated nomenclature of the species. A new, detailed description of P. neesii with illustrations is provided after comparison of sequenced specimens with the type material. Furthermore, the new combination Pseudographis rufonigra (basionym Peziza rufonigra) is made for a fungus previously known as Pseudographis pinicola.

First results from the Cryogenic Dark Matter Search in the Soudan Underground Laboratory

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg d of Ge net exposure after cuts for recoil energies between 10 and 100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using the standard dark-matter halo and nuclear-physics WIMP model, these data set the world's lowest exclusion limits on the coherent WIMP-nucleon scalar cross section for all WIMP masses above 15 GeV/c2, ruling out a significant range of neutralino supersymmetric models. The minimum of this limit curve at the 90% C.L. is 4 x 10(-43) cm2 at a WIMP mass of 60 GeV/c2.

Induction of ubiquitin-conjugating enzymes during terminal erythroid differentiation

A global cellular reorganization occurs during the reticulocyte stage of erythroid differentiation. This reorganization is accomplished partly through programmed protein degradation. The selection of proteins for degradation can be mediated by covalent attachment of ubiquitin. We have cloned cDNAs encoding two ubiquitin-conjugating (E2) enzymes, E2-20K and E2-230K, and found their genes to be strongly induced during the differentiation of erythroblasts into reticulocytes. Induction of the E2-20K and E2-230K genes is specific, as transcript levels for at least two other ubiquitinating enzymes fall during erythroblast differentiation. In contrast to most proteins induced in reticulocytes, E2-20K and E2-230K enzymes are present at strongly reduced levels in erythrocytes and thus decline in abundance as reticulocyte maturation is completed. This result suggests that both enzymes function during the reticulocyte stage, when enhanced protein degradation has been observed. These data implicate regulated components of the ubiquitin conjugation machinery in erythroid differentiation.