Structural Changes in the Red Spruce-Fraser Fir Forest

Since the early 1900s the southern Appalachian red spruce (Picea rubens Sarg.)-Fraser fir (Abies piceae (Pursh) Poir.) forests have been subjected to numerous destructive influences. Historical logging practices, fire, exotic insect infestations, acidic deposition, and global climate change have demonstratively altered the structure and composition of this fragile ecosystem. Most profound was the discovery in 1957 of the balsam woolly adelgid (Adelges piceae Ratz. Homoptera: Adelgidae ), an exotic sap-sucking aphid. A study was initiated in the Great Smoky Mountains National Park, which contains 74% of the red spruce-Fraser ecosystem. Thirty-six 20x20 m permanent plots untouched by logging were established in 1990 on five high elevation mountain peaks to monitor the changes in the forest and were re-sampled in 2000-01. From the late 1940s to 1990-91, live fir basal area decreased by 6.64 m2/ha. Between 1990-91 and 2000 live fir density increased by 156 stems/ha. Despite the increase in density this second generation of Fraser fir remained sparse compared to the 1940s. All of the species in the sapling cohort (\u3c5cm diameter at breast height (dbh), and ≥1.37m tall) increased showing a positive response to overstory deterioration. All species in the seedling cohort (\u3c1.37m tall) decreased exhibiting the effects of inhibition from the sapling layer, voids in seed years, and germination difficulty from lack of soil moisture. Mean age of all seedling and sapling size fir decreased since 190-91 suggesting a faster growing second generation in 2000. Mortality rates of all overstory species decreased since the late 1980s. However, the future of this young cohort of understory trees in unknown. A dense even-aged forest could create the ideal habitat of the adelgid, causing another rapid outbreak. If adelgid populations do not stabilize and Fraser fir does not develop a resistance this cohort could be in jeopardy once it reaches maturity. Provided it lives long enough to produce viable seed it will become a two-aged forest never reaching the old growth un-even aged structure that existed prior to infestation

Molecular profiling and combinatorial activity of CCT068127: a potent CDK2 and CDK9 inhibitor

Deregulation of the cyclin-dependent kinases (CDKs) has been implicated in the pathogenesis of multiple cancer types. Consequently, CDKs have garnered intense interest as therapeutic targets for the treatment of cancer. We describe herein the molecular and cellular effects of CCT068127, a novel inhibitor of CDK2 and CDK9. Optimised from the purine template of seliciclib, CCT068127 exhibits greater potency and selectivity against purified CDK2 and CDK9 and superior antiproliferative activity against human colon cancer and melanoma cell lines. X-ray crystallography studies reveal that hydrogen bonding with the DFG motif of CDK2 is the likely mechanism of greater enzymatic potency. Commensurate with inhibition of CDK activity, CCT068127 treatment results in decreased retinoblastoma protein (RB) phosphorylation, reduced phosphorylation of RNA polymerase II and induction of cell cycle arrest and apoptosis. The transcriptional signature of CCT068127 shows greatest similarity to other small molecule CDK and also HDAC inhibitors. CCT068127 caused a dramatic loss in expression of DUSP6 phosphatase, alongside elevated ERK phosphorylation and activation of MAPK pathway target genes. MCL1 protein levels are rapidly decreased by CCT068127 treatment and this associates with synergistic antiproliferative activity after combined treatment with CCT068127 and ABT263, a BCL2-family inhibitor. These findings support the rational combination of this series of CDK2/9 inhibitors and BCL2 family inhibitors for the treatment of human cancer

Nuclear astrophysics with radioactive ions at FAIR

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes