Principles of protein-protein interactions.

This review examines protein complexes in the Brookhaven Protein Databank to gain a better understanding of the principles governing the interactions involved in protein-protein recognition. The factors that influence the formation of protein-protein complexes are explored in four different types of protein-protein complexes--homodimeric proteins, heterodimeric proteins, enzyme-inhibitor complexes, and antibody-protein complexes. The comparison between the complexes highlights differences that reflect their biological roles.

Inhibition of human immunodeficiency virus type 1 and vaccinia virus infection by a dominant negative factor of the interferon regulatory factor family expressed in monocytic cells.

ICSBP is a member of the interferon (IFN) regulatory factor (IRF) family that regulates expression of type I interferon (IFN) and IFN-regulated genes. To study the role of the IRF family in viral infection, a cDNA for the DNA-binding domain (DBD) of ICSBP was stably transfected into U937 human monocytic cells. Clones that expressed DBD exhibited a dominant negative phenotype and did not elicit antiviral activity against vesicular stomatitis virus (VSV) infection upon IFN treatment. Most notably, cells expressing DBD were refractory to infection by vaccinia virus (VV) and human immunodeficiency virus type 1 (HIV-1). The inhibition of VV infection was attributed to defective virion assembly, and that of HIV-1 to low CD4 expression and inhibition of viral transcription in DBD clones. HIV-1 and VV were found to have sequences in their regulatory regions similar to the IFN-stimulated response element (ISRE) to which IRF family proteins bind. Accordingly, these viral sequences and a cellular ISRE bound a shared factor(s) expressed in U937 cells. These observations suggest a novel host-virus relationship in which the productive infection of some viruses is regulated by the IRF-dependent transcription pathway through the ISRE.

Y chromosome short arm-Sxr recombination in XSxr/Y males causes deletion of Rbm and XY female sex reversal.

We earlier described three lines of sex-reversed XY female mice deleted for sequences believed close to the testes-determining gene (Sry) on the Y chromosome short arm (Yp). The original sex-reversed females appeared among the offspring of XY males that carried the Yp duplication Sxr on their X chromosome. Earlier cytogenetic observations had suggested that the deletions resulted from asymmetrical meiotic recombination between the Y and the homologous Sxr region, but no direct evidence for this hypothesis was available. We have now analyzed the offspring of XSxr/Y males carrying an evolutionarily divergent Mus musculus domesticus Y chromosome, which permits detection and characterization of such recombination events. This analysis has enabled the derivation of a recombination map of Yp and Sxr, also demonstrating the orientation of Yp with respect to the Y centromere. The mapping data have established that Rbm, the murine homologue of a gene family cloned from the human Y chromosome, lies between Sry and the centromere. Analysis of two additional XY female lines shows that asymmetrical Yp-Sxr recombination leading to XY female sex reversal results in deletion of Rbm sequences. The deletions bring Sry closer to Y centromere, consistent with the hypothesis that position-effect inactivation of Sry is the basis for the sex reversal.

Effects of high-color-discrimination capability spectra on color-deficient vision

Light sources with three spectral bands in specific spectral positions are known to have high-color-discrimination capability. W. A. Thornton hypothesized that they may also enhance color discrimination for color-deficient observers. This hypothesis was tested here by comparing the Rösch–MacAdam color volume for color-deficient observers rendered by three of these singular spectra, two reported previously and one derived in this paper by maximization of the Rösch–MacAdam color solid. It was found that all illuminants tested enhance discriminability for deuteranomalous observers, but their impact on other congenital deficiencies was variable. The best illuminant was the one derived here, as it was clearly advantageous for the two red–green anomalies and for tritanopes and almost neutral for red–green dichromats. We conclude that three-band spectra with high-color-discrimination capability for normal observers do not necessarily produce comparable enhancements for color-deficient observers, but suitable spectral optimization clearly enhances the vision of the color deficient.

Chitosan enhances parasitism of Meloidogyne javanica eggs by the nematophagous fungus Pochonia chlamydosporia

Pochonia chlamydosporia (Pc), a nematophagous fungus and root endophyte, uses appressoria and extracellular enzymes, principally proteases, to infect the eggs of plant parasitic nematodes (PPN). Unlike other fungi, Pc is resistant to chitosan, a deacetylated form of chitin, used in agriculture as a biopesticide to control plant pathogens. In the present work, we show that chitosan increases Meloidogyne javanica egg parasitism by P. chlamydosporia. Using antibodies specific to the Pc enzymes VCP1 (a subtilisin), and SCP1 (a serine carboxypeptidase), we demonstrate chitosan elicitation of the fungal proteases during the parasitic process. Chitosan increases VCP1 immuno-labelling in the cell wall of Pc conidia, hyphal tips of germinating spores, and in appressoria on infected M. javanica eggs. These results support the role of proteases in egg parasitism by the fungus and their activation by chitosan. Phylogenetic analysis of the Pc genome reveals a large diversity of subtilisins (S8) and serine carboxypeptidases (S10). The VCP1 group in the S8 tree shows evidence of gene duplication indicating recent adaptations to nutrient sources. Our results demonstrate that chitosan enhances Pc infectivity of nematode eggs through increased proteolytic activities and appressoria formation and might be used to improve the efficacy of M. javanica biocontrol.

Subjects suggested by John Farrar, ca. 1820s

A handwritten letter to President John Thornton Kirkland with five suggested subjects from John Farrar, the Hollis Professor of Mathematics and Natural Philosophy from 1807 until 1836.

Emmons's notes on Field Museum's collection of Northwest Coast basketry: edited with an ethnoarchaeological analysis / Ronald L. Weber.

n.s. no.9(1986)

X. Harvard College Papers, 1st series, Volume 10, 1821-1824, 1831

The tenth volume of College Papers contains original documents dating from 1821 to 1824, spanning the tenures of president John Thornton Kirkland and treasurer John Davis. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis, as well as correspondence between Davis and Steward Stephen Higginson. It also contains a printed document from 1831, during the tenure of president Josiah Quincy.

XI. Harvard College Papers, 1st series, Volume 11, 1824-1825

The eleventh volume of College Papers contains original documents from 1824 to 1825, spanning the tenures of president John Thornton Kirkland and treasurer John Davis. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis, as well as correspondence between Davis and Steward Stephen Higginson.

VI. Harvard College Papers, 1st series, Volume 6, 1809-1811

The sixth volume of College Papers contains original documents dating from 1809 to 1811, spanning the tenures of presidents Samuel Webber and John Thornton Kirkland, and treasurers Jonathan Jackson and John Davis. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis.

VII. Harvard College Papers, 1st series, Volume 7, 1811-1815, 1819

The seventh volume of the College Papers contains original documents dating from 1811 to 1815, spanning the tenures of president John Thornton Kirkland and treasurer John Davis. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis. It also contains one document from 1819.

VIII. Harvard College Papers, 1st series, Volume 8, 1815-1820 (bulk 1815-1819)

The eighth volume of College Papers contains original documents dating from 1815 to 1819, spanning the tenures of president John Thornton Kirkland and treasurer John Davis. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis. It also contains a document from 1820.

IX. Harvard College Papers, 1st series, Volume 9, 1819-1821

The ninth volume of College Papers contains original documents dating from 1819 to 1821, spanning the tenures of president John Thornton Kirkland and treasurer John Davis, as well as correspondence between Davis and Steward Stephen Higginson. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis. It also contains an early 20th century typewritten document.

VI. Harvard College Papers, 1st series, Volume 6, 1809-1811

The sixth volume of College Papers contains original documents dating from 1809 to 1811, spanning the tenures of presidents Samuel Webber and John Thornton Kirkland, and treasurers Jonathan Jackson and John Davis. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis.

VII. Harvard College Papers, 1st series, Volume 7, 1811-1815, 1819

The seventh volume of the College Papers contains original documents dating from 1811 to 1815, spanning the tenures of president John Thornton Kirkland and treasurer John Davis. Much of the volume consists of general administrative correspondence exchanged between Kirkland and Davis. It also contains one document from 1819.