Network Hubs Buffer Environmental Variation in Saccharomyces cerevisiae

Regulatory and developmental systems produce phenotypes that are robust to environmental and genetic variation. A gene product that normally contributes to this robustness is termed a phenotypic capacitor. When a phenotypic capacitor fails, for example when challenged by a harsh environment or mutation, the system becomes less robust and thus produces greater phenotypic variation. A functional phenotypic capacitor provides a mechanism by which hidden polymorphism can accumulate, whereas its failure provides a mechanism by which evolutionary change might be promoted. The primary example to date of a phenotypic capacitor is Hsp90, a molecular chaperone that targets a large set of signal transduction proteins. In both Drosophila and Arabidopsis, compromised Hsp90 function results in pleiotropic phenotypic effects dependent on the underlying genotype. For some traits, Hsp90 also appears to buffer stochastic variation, yet the relationship between environmental and genetic buffering remains an important unresolved question. We previously used simulations of knockout mutations in transcriptional networks to predict that many gene products would act as phenotypic capacitors. To test this prediction, we use high-throughput morphological phenotyping of individual yeast cells from single-gene deletion strains to identify gene products that buffer environmental variation in Saccharomyces cerevisiae. We find more than 300 gene products that, when absent, increase morphological variation. Overrepresented among these capacitors are gene products that control chromosome organization and DNA integrity, RNA elongation, protein modification, cell cycle, and response to stimuli such as stress. Capacitors have a high number of synthetic-lethal interactions but knockouts of these genes do not tend to cause severe decreases in growth rate. Each capacitor can be classified based on whether or not it is encoded by a gene with a paralog in the genome. Capacitors with a duplicate are highly connected in the protein–protein interaction network and show considerable divergence in expression from their paralogs. In contrast, capacitors encoded by singleton genes are part of highly interconnected protein clusters whose other members also tend to affect phenotypic variability or fitness. These results suggest that buffering and release of variation is a widespread phenomenon that is caused by incomplete functional redundancy at multiple levels in the genetic architecture

The Ursinus Weekly, November 4, 1963

Speech by local leader highlights Founders Day • AAUW to meet on Ursinus campus • Dr. Robert Howard named to Who\u27s who • 40 music lovers to hear concert • Quaker journalist to present lecture on Cuban visit • Election of queen to begin Homecoming festivities • Peace pilgrim visits campus • Improved Lantern planned by editors • Folk singer to appear at UC Friday night • IFC plans party as Homecoming opener • Summer reading sessions end • New officer to present Wave program Nov. 7 • Items from abroad • Letters to the editor • Foreign students give views of US • Main Line Symphony announces guest soloist • Dear Wormwood cast in rehearsal • Youth organizes for Goldwater • Greek gleanings • Student organizing group to work at St. Gabriel\u27s • MSGA busy with many new projects • Mrs. Parsons to address Ursinus Circle Nov. 7 • Bears run into Seahawk deepfreeze • Intramural corner • Interview: Bob Mashock • Soccer team set back despite fine efforts • UC hockey teams win againhttps://digitalcommons.ursinus.edu/weekly/1256/thumbnail.jp

Gamma-ray signatures of annihilation to charged leptons in dark matter substructure

Due to their higher concentrations and small internal velocities, Milky Way subhalos can be at least as important as the smooth halo in accounting for the GeV positron excess via dark matter annihilation. After showing how this can be achieved in various scenarios, including in Sommerfeld models, we demonstrate that, in this case, the diffuse inverse-Compton emission resulting from electrons and positrons produced in substructure leads to a nearly-isotropic signal close to the level of the isotropic GeV gamma-ray background seen by Fermi. Moreover, we show that HESS cosmic-ray electron measurements can be used to constrain multi-TeV internal bremsstrahlung gamma rays arising from annihilation to charged leptons.Comment: 8 pages, 4 figures; minor updates to match published versio

Predicting Second and Third Graders' Reading Comprehension Gains: Observing Students' and Classmates Talk during Literacy Instruction using COLT.

This paper introduces a new observation system that is designed to investigate students' and teachers' talk during literacy instruction, Creating Opportunities to Learn from Text (COLT). Using video-recorded observations of 2nd-3rd grade literacy instruction (N=51 classrooms, 337 students, 151 observations), we found that nine types of student talk ranged from using non-verbal gestures to generating new ideas. The more a student talked, the greater were his/her reading comprehension (RC) gains. Classmate talk also predicted RC outcomes (total effect size=0.27). We found that 11 types of teacher talk ranged from asking simple questions to encouraging students' thinking and reasoning. Teacher talk predicted student talk but did not predict students' RC gains directly. Findings highlight the importance of each student's discourse during literacy instruction, how classmates' talk contributes to the learning environments that each student experiences, and how this affects RC gains, with implications for improving the effectiveness of literacy instruction

The detection of geothermal areas from Skylab thermal data

Skylab-4 X-5 thermal data of the geysers area was analyzed to determine the feasibility of using midday Skylab images to detect geothermal areas. The hottest ground areas indicated on the Skylab image corresponded to south-facing barren or sparsely vegetated slopes. A geothermal area approximately 15 by 30 m coincided with one of the hottest areas indicated by Skylab. This area could not be unambiguously distinguished from the other areas which are believed to be hotter than their surroundings as a result of their topography, and micrometeorological conditions. A simple modification of a previous thermal model was performed and the predicted temperatures for the hottest slopes using representative values was in general agreement with the observed data. It is concluded that data from a single midday Skylab pass cannot be used to locate geothermal areas

Ariel - Volume 11 Number 2

Executive Editors Ellen Feldman Leonardo S. Nasca, Jr. Business .Managers Barbara L. Davies Martin B. Getzow News Editor Aaron D. Bleznak Features Editor Hugh A. Gelabert CAHS Editor Joan M. Greco Editorial Page Editor Samuel Markind Photography Editor Leonardo S. Nasca, Jr. Sports Editor Paul F. Mansfiel

New Sensitivity to Solar WIMP Annihilation using Low-Energy Neutrinos

Dark matter particles captured by the Sun through scattering may annihilate and produce neutrinos, which escape. Current searches are for the few high-energy neutrinos produced in the prompt decays of some final states. We show that interactions in the solar medium lead to a large number of pions for nearly all final states. Positive pions and muons decay at rest, producing low-energy neutrinos with known spectra, including nuebar through neutrino mixing. We demonstrate that Super-Kamiokande can thereby provide a new probe of the spin-dependent WIMP-proton cross section. Compared to other methods, the sensitivity is competitive and the uncertainties are complementary.Comment: 5 pages, 4 figure

The Ursinus Weekly, May 13, 1963

Bears annex first MAC championship • Cold weather doesn\u27t freeze Mississippi mud • Senior show slated for May 16 • Sir George Thomson, famed physicist, to speak at Commencement exercises • Joyce Maloney wins title of Miss Montgomery County • Registration open for Summer school • Angelo Cutone, custodian, plans return to Italy • Pre-med society selects officers • Music Club names 1963-64 officers • Shinnick, Kelly, Gould elected class presidents • Whitians elect 1963-64 leaders • Dr. Steere urges understanding • Peggy Cooper new head cheerleader • GOP elects officers • New officers • As Helfferich leaves Girard Trust • Greek gleanings • UC Band presents Spring concert • Minutes of MSGA • Tibetan lamas • Fine casting and producing lead Staring match to success • Ursinus smites fiery Dragons 8-1; Bears give explorers victory 9-5 • Tennis team trims the Main Line • Jim Egolf: Freshman find • Ursinus racketeers stumble • Haverford beaten second time, 6-2 • UC shears Ewes • Bears drop Shoremen from undefeated ranks • Lacrosse team drops WC, 6-4https://digitalcommons.ursinus.edu/weekly/1296/thumbnail.jp

Surface Structure of Tetrahedral-Coordinated Amorphous Diamond-Like Carbon Films Grown by Pulsed Laser Deposition

The structure and composition of tetrahedral-coordinated amorphous diamond-like carbon films (a-tC) grown by pulsed laser deposition (PLD) of graphite has been studied with atomic force microscopy (AFM). The nanometer-scale surface structure has been studied as a function of growth parameters (e.g., laser energy density and film thickness) using contact-mode and tapping-mode AFM. Although the surfaces were found to be generally smooth, they exhibited reproducible structural features on several size scales which correlate with the variation of laser energy and th excited ion etching

Apoptotic depletion of CD4<SUP>+</SUP> T cells in idiopathic CD4<SUP>+</SUP> T lymphocytopenia

Progressive loss of CD4+ T lymphocytes, accompanied by opportunistic infections characteristic of the acquired immune deficiency syndrome, ahs been reported in the absence of any known etiology. The pathogenesis of this syndrome, a subset of idiopathic CD4+ T lymphocytopenia (ICL), is uncertain. We report that CD4+ T cells from seven of eight ICL patients underwent accelerated programmed cell death, a process facilitated by T cell receptor cross-linking. Apoptosis was associated with enhanced expression of Fas and Fas ligand in unstimulated cell populations, and partially inhibited by soluble anti-Fas mAb. In addition, apoptosis was suppressed by aurintricarboxylic acid, an inhibitor of calcium-dependent endonucleases and proteases, in cells from four of seven patients, The in vivo significance of these findings was supported by three factors: the absence of accelerated apoptosis in persons with stable, physiologic CD4 lymphopenia without clinical immune deficiency; detection of serum antihistone H2B autoantibodies, one consequence of DNA fragmentation, in some patients; and its selectivity, with apoptosis limited to the CD4 population in some, and occurring among CD8+ T cells predominantly in those individuals with marked depletion of both CD4+ T lymphocytes linked to clinical immune suppression have evidence for accelerated T cell apoptosis in vitro that may be pathophysiologic and amenable to therapy with apoptosis inhibitors