Select pyrimidinones inhibit the propagation of the malarial parasite, Plasmodium falciparum

Plasmodium falciparum, the Apicomplexan parasite that is responsible for the most lethal forms of human malaria, is exposed to radically different environments and stress factors during its complex lifecycle. In any organism, Hsp70 chaperones are typically associated with tolerance to stress. We therefore reasoned that inhibition of P. falciparum Hsp70 chaperones would adversely affect parasite homeostasis. To test this hypothesis, we measured whether pyrimidinone-amides, a new class of Hsp70 modulators, could inhibit the replication of the pathogenic P. falciparum stages in human red blood cells. Nine compounds with IC50 values from 30 nM to 1.6 μM were identified. Each compound also altered the ATPase activity of purified P. falciparum Hsp70 in single-turnover assays, although higher concentrations of agents were required than was necessary to inhibit P. falciparum replication. Varying effects of these compounds on Hsp70s from other organisms were also observed. Together, our data indicate that pyrimidinone-amides constitute a novel class of anti-malarial agents. © 2009 Elsevier Ltd. All rights reserved

Precision measurement of spin-dependent interaction strengths for spin-1 and spin-2 87Rb atoms

We report on precision measurements of spin-dependent interaction-strengths in the 87Rb spin-1 and spin-2 hyperfine ground states. Our method is based on the recent observation of coherence in the collisionally driven spin-dynamics of ultracold atom pairs trapped in optical lattices. Analysis of the Rabi-type oscillations between two spin states of an atom pair allows a direct determination of the coupling parameters in the interaction hamiltonian. We deduce differences in scattering lengths from our data that can directly be compared to theoretical predictions in order to test interatomic potentials. Our measurements agree with the predictions within 20%. The knowledge of these coupling parameters allows one to determine the nature of the magnetic ground state. Our data imply a ferromagnetic ground state for 87Rb in the f=1 manifold, in agreement with earlier experiments performed without the optical lattice. For 87Rb in the f=2 manifold the data points towards an antiferromagnetic ground state, however our error bars do not exclude a possible cyclic phase.Comment: 11 pages, 5 figure

Adiabatic population transfer via multiple intermediate states

This paper discusses a generalization of stimulated Raman adiabatic passage (STIRAP) in which the single intermediate state is replaced by $N$ intermediate states. Each of these states is connected to the initial state \state{i} with a coupling proportional to the pump pulse and to the final state \state{f} with a coupling proportional to the Stokes pulse, thus forming a parallel multi-$\Lambda$ system. It is shown that the dark (trapped) state exists only when the ratio between each pump coupling and the respective Stokes coupling is the same for all intermediate states. We derive the conditions for existence of a more general adiabatic-transfer state which includes transient contributions from the intermediate states but still transfers the population from state \state{i} to state \state{f} in the adiabatic limit. We present various numerical examples for success and failure of multi-$\Lambda$ STIRAP which illustrate the analytic predictions. Our results suggest that in the general case of arbitrary couplings, it is most appropriate to tune the pump and Stokes lasers either just below or just above all intermediate states.Comment: 14 pages, two-column revtex style, 10 figure

Methods for Assessing Child and Family Outcomes in Early Childhood Special Education Programs

Although many concerns have been raised about methods of assessing outcomes in early childhood special education programs, professionals in the field are nevertheless faced with the need to select appropriate instruments for evaluating child and family outcomes as the result of intervention. A conference to address the current assessment needs of professionals was convened. This paper summarizes this conference, in which five prominent individuals in the field of early childhood special education gave specific recommendations for one child and one family outcome measure which would be applicable to a range of handicapped children between birth and age 5 being served in typical early intervention programs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68510/2/10.1177_027112148600600202.pd

Mutational Analysis of EGFR and Related Signaling Pathway Genes in Lung Adenocarcinomas Identifies a Novel Somatic Kinase Domain Mutation in FGFR4

BACKGROUND: Fifty percent of lung adenocarcinomas harbor somatic mutations in six genes that encode proteins in the EGFR signaling pathway, i.e., EGFR, HER2/ERBB2, HER4/ERBB4, PIK3CA, BRAF, and KRAS. We performed mutational profiling of a large cohort of lung adenocarcinomas to uncover other potential somatic mutations in genes of this signaling pathway that could contribute to lung tumorigenesis. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed genomic DNA from a total of 261 resected, clinically annotated non-small cell lung cancer (NSCLC) specimens. The coding sequences of 39 genes were screened for somatic mutations via high-throughput dideoxynucleotide sequencing of PCR-amplified gene products. Mutations were considered to be somatic only if they were found in an independent tumor-derived PCR product but not in matched normal tissue. Sequencing of 9MB of tumor sequence identified 239 putative genetic variants. We further examined 22 variants found in RAS family genes and 135 variants localized to exons encoding the kinase domain of respective proteins. We identified a total of 37 non-synonymous somatic mutations; 36 were found collectively in EGFR, KRAS, BRAF, and PIK3CA. One somatic mutation was a previously unreported mutation in the kinase domain (exon 16) of FGFR4 (Glu681Lys), identified in 1 of 158 tumors. The FGFR4 mutation is analogous to a reported tumor-specific somatic mutation in ERBB2 and is located in the same exon as a previously reported kinase domain mutation in FGFR4 (Pro712Thr) in a lung adenocarcinoma cell line. CONCLUSIONS/SIGNIFICANCE: This study is one of the first comprehensive mutational analyses of major genes in a specific signaling pathway in a sizeable cohort of lung adenocarcinomas. Our results suggest the majority of gain-of-function mutations within kinase genes in the EGFR signaling pathway have already been identified. Our findings also implicate FGFR4 in the pathogenesis of a subset of lung adenocarcinomas

Defining the Specificity of Cotranslationally Acting Chaperones by Systematic Analysis of mRNAs Associated with Ribosome-Nascent Chain Complexes

Polypeptides exiting the ribosome must fold and assemble in the crowded environment of the cell. Chaperones and other protein homeostasis factors interact with newly translated polypeptides to facilitate their folding and correct localization. Despite the extensive efforts, little is known about the specificity of the chaperones and other factors that bind nascent polypeptides. To address this question we present an approach that systematically identifies cotranslational chaperone substrates through the mRNAs associated with ribosome-nascent chain-chaperone complexes. We here focused on two Saccharomyces cerevisiae chaperones: the Signal Recognition Particle (SRP), which acts cotranslationally to target proteins to the ER, and the Nascent chain Associated Complex (NAC), whose function has been elusive. Our results provide new insights into SRP selectivity and reveal that NAC is a general cotranslational chaperone. We found surprising differential substrate specificity for the three subunits of NAC, which appear to recognize distinct features within nascent chains. Our results also revealed a partial overlap between the sets of nascent polypeptides that interact with NAC and SRP, respectively, and showed that NAC modulates SRP specificity and fidelity in vivo. These findings give us new insight into the dynamic interplay of chaperones acting on nascent chains. The strategy we used should be generally applicable to mapping the specificity, interplay, and dynamics of the cotranslational protein homeostasis network

Diverse Forms of RPS9 Splicing Are Part of an Evolving Autoregulatory Circuit

Ribosomal proteins are essential to life. While the functions of ribosomal protein-encoding genes (RPGs) are highly conserved, the evolution of their regulatory mechanisms is remarkably dynamic. In Saccharomyces cerevisiae, RPGs are unusual in that they are commonly present as two highly similar gene copies and in that they are over-represented among intron-containing genes. To investigate the role of introns in the regulation of RPG expression, we constructed 16 S. cerevisiae strains with precise deletions of RPG introns. We found that several yeast introns function to repress rather than to increase steady-state mRNA levels. Among these, the RPS9A and RPS9B introns were required for cross-regulation of the two paralogous gene copies, which is consistent with the duplication of an autoregulatory circuit. To test for similar intron function in animals, we performed an experimental test and comparative analyses for autoregulation among distantly related animal RPS9 orthologs. Overexpression of an exogenous RpS9 copy in Drosophila melanogaster S2 cells induced alternative splicing and degradation of the endogenous copy by nonsense-mediated decay (NMD). Also, analysis of expressed sequence tag data from distantly related animals, including Homo sapiens and Ciona intestinalis, revealed diverse alternatively-spliced RPS9 isoforms predicted to elicit NMD. We propose that multiple forms of splicing regulation among RPS9 orthologs from various eukaryotes operate analogously to translational repression of the alpha operon by S4, the distant prokaryotic ortholog. Thus, RPS9 orthologs appear to have independently evolved variations on a fundamental autoregulatory circuit