A conditional probability analysis of cystic fibrosis transmembrane conductance regulator gating indicates that ATP has multiple effects during the gating cycle

ATP-binding cassette (ABC) transporters bind and hydrolyze ATP. In the cystic fibrosis transmembrane conductance regulator Cl− channel, this interaction with ATP generates a gating cycle between a closed (C) and two open (O1 and O2) conformations. To understand better how ATP controls channel activity, we examined gating transitions from the C to the O1 and O2 states and from these open states to the C conformation. We made three main observations. First, we found that the channel can open into either the O1 or O2 state, that the frequency of transitions to both states was increased by ATP concentration, and that ATP increased the relative proportion of openings into O1 vs. O2. These results indicate that ATP can interact with the closed state to open the channel in at least two ways, which may involve binding to nucleotide-binding domains (NBDs) NBD1 and NBD2. Second, ATP prolonged the burst duration and altered the way in which the channel closed. These data suggest that ATP also interacts with the open channel. Third, the channel showed runs of specific types of open–closed transitions. This finding suggests a mechanism with more than one cycle of gating transitions. These data suggest models to explain how ATP influences conformational transitions in cystic fibrosis transmembrane conductance regulator and perhaps other ABC transporters.

Three-dimensional image reconstruction of dephosphorylated smooth muscle heavy meromyosin reveals asymmetry in the interaction between myosin heads and placement of subfragment 2

Regulation of the actin-activated ATPase of smooth muscle myosin II is known to involve an interaction between the two heads that is controlled by phosphorylation of the regulatory light chain. However, the three-dimensional structure of this inactivated form has been unknown. We have used a lipid monolayer to obtain two-dimensional crystalline arrays of the unphosphorylated inactive form of smooth muscle heavy meromyosin suitable for structural studies by electron cryomicroscopy of unstained, frozen-hydrated specimens. The three-dimensional structure reveals an asymmetric interaction between the two myosin heads. The ATPase activity of one head is sterically “blocked” because part of its actin-binding interface is positioned onto the converter domain of the second head. ATPase activity of the second head, which can bind actin, appears to be inhibited through stabilization of converter domain movements needed to release phosphate and achieve strong actin binding. When the subfragment 2 domain of heavy meromyosin is oriented as it would be in an actomyosin filament lattice, the position of the heads is very different from that needed to bind actin, suggesting an additional contribution to ATPase inhibition in situ.

DEG/ENaC ion channels involved in sensory transduction are modulated by cold temperature

Several DEG/ENaC cation channel subunits are expressed in the tongue and in cutaneous sensory neurons, where they are postulated to function as receptors for salt and sour taste and for touch. Because these tissues are exposed to large temperature variations, we examined how temperature affects DEG/ENaC channel function. We found that cold temperature markedly increased the constitutively active Na+ currents generated by epithelial Na+ channels (ENaC). Half-maximal stimulation occurred at 25°C. Cold temperature did not induce current from other DEG/ENaC family members (BNC1, ASIC, and DRASIC). However, when these channels were activated by acid, cold temperature potentiated the currents by slowing the rate of desensitization. Potentiation was abolished by a “Deg” mutation that alters channel gating. Temperature changes in the physiologic range had prominent effects on current in cells heterologously expressing acid-gated DEG/ENaC channels, as well as in dorsal root ganglion sensory neurons. The finding that cold temperature modulates DEG/ENaC channel function may provide a molecular explanation for the widely recognized ability of temperature to modify taste sensation and mechanosensation.

Genome-wide gene expression profiles of the developing mouse hippocampus

We have analyzed the developmental molecular programs of the mouse hippocampus, a cortical structure critical for learning and memory, by means of large-scale DNA microarray techniques. Of 11,000 genes and expressed sequence tags examined, 1,926 showed dynamic changes during hippocampal development from embryonic day 16 to postnatal day 30. Gene-cluster analysis was used to group these genes into 16 distinct clusters with striking patterns that appear to correlate with major developmental hallmarks and cellular events. These include genes involved in neuronal proliferation, differentiation, and synapse formation. A complete list of the transcriptional changes has been compiled into a comprehensive gene profile database (http://BrainGenomics.Princeton.edu), which should prove valuable in advancing our understanding of the molecular and genetic programs underlying both the development and the functions of the mammalian brain.

College Book 8, 1778-1803

This volume contains a fair copy of minutes from Corporation meetings held from May 5, 1778 through October 14, 1803. It begins with an alphabetical index and contains entries related to a wide range of topics, including changes in the College laws; lists of Harvard graduates; historical information about the College and its governance; memorials to the Massachusetts General Court about currency concerns, the West Boston Bridge, and other matters; the establishment of medical professorships and selection of professors to fill them; land and property belonging to Harvard; the settlement of accounts with former College Treasurer John Hancock; support of missionaries to several Indian tribes; the establishment of a student dress code; the Charlestown Ferry, and its revenue troubles following the construction of the West Boston Bridge; the purchase of a wooden sloop for transporting students' "fuel" (presumably firewood); the creation and distribution of library catalogs; the commission of a lucernal microscope for the College Apparatus; Oneida Indian Isaac Solegwaston and Harvard's financial support of his studies at the Hamilton Oneida Academy; transcriptions of a letter (October 23, 1789) from the Corporation to President George Washington and of Washington's response; a petition to the General Court for the establishment of a public infirmary to serve the indigent; individuals who were granted permission to instruct Harvard students in the French language outside the established curriculum; and Thomas Welsh's excused absence from his Harvard graduation, granted June 14, 1798, because of his imminent departure for Berlin to serve as Secretary to John Quincy Adams, then Minister Plenipotentiary to Berlin.

Lawyer's commonplace book, 1774-1783

Contains entries on a variety of topics arranged alphabetically and compiled by several individuals. Includes an index at the end.

John Warren's copy of votes from a meeting of the Boston Medical Society, 1784 May 3

This document lists the eleven votes cast at a meeting of the Boston Medical Society on May 3, 1784. It was authorized as a "true coppy" by Thomas Kast, the Secretary of the Society. The following members of the Society were present at the meeting, all of them doctors: James Pecker, James Lloyd, Joseph Gardner, Samuel Danforth, Isaac Rand, Jr., Charles Jarvis, Thomas Kast, Benjamin Curtis, Thomas Welsh, Nathaniel Walker Appleton, and doctors whose last names were Adams, Townsend, Eustis, Homans, and Whitwell. The document indicates that a meeting had been held the previous evening, as well (May 2, 1784), at which the topics on which votes were taken had been discussed. The votes, eleven in total, were all related to the doctors' concerns about John Warren and his involvement with the emerging medical school (now Harvard Medical School), that school's relation to almshouses, the medical care of the poor, and other related matters. The tone and content of these votes reveals anger on the part of the members of the Boston Medical Society towards Warren. This anger appears to have stemmed from the perceived threat of Warren to their own practices, exacerbated by a vote of the Harvard Corporation on April 19, 1784. This vote authorized Warren to apply to the Overseers of the Poor for the town of Boston, requesting that students in the newly-established Harvard medical program, where Warren was Professor of Anatomy and Surgery, be allowed to visit the hospital of the almshouse with their professors for the purpose of clinical instruction. Although Warren believed that the students would learn far more from these visits, in regards to surgical experience, than they could possibly learn in Cambridge, the proposal provoked great distrust from the members of the Boston Medical Society, who accused Warren of an "attempt to direct the public medical business from its usual channels" for his own financial and professional gain.

Disentangling the Reform Gridlock: Higher Education in Germany. CES Germany & Europe Working Papers, No. 02.7, 2002

For more than a decade, bemoaning the many roadblocks to reforming important aspect of German politics has become commonplace. Explanations emphasize formal and informal veto points, such as the role of political institutions and the lack of elite and societal support for reform initiatives. Against this background, I was interested in factors that place policy issues on the political agenda and follow up with concrete courses of action; i.e., in factors that lead to a disentangling of the reform gridlock. I emphasize the importance of agenda setting in the emergence of higher education reform in Germany. Globalization, European integration and domestic pressures combined to create new pressures for change. In response, an advocacy coalition of old and new political actors has introduced a drawn-out and ongoing process of value reorientation in the direction of competition, including international competition, and greater autonomy. The result has been a burst of activities, some moderate, some more far-reaching in their potential to restructure German higher education.

Dark days,

Spec. Coll. PR 4699 F16c: With the author's Called back. Bristol, 1884.

Ayer's American almanac : for the use of farmers, planters, mechanics, and all families ...

Issue for 1889 includes French, Spanish, Portuguese, Finnish, German, Dutch, Swedish, Norwegian-Danish, Bohemian, Welsh, and Italian sections.

Development of materials and public relations efforts to promote child passenger safety. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Judicial perspectives on child passenger protection legislation. Final report.

National Highway Traffic Safety Administration, Washington, D.C.