Characterization of Metal Transport by the Streptococcus sanguinis Endocarditis Virulence Factor SsaB

Streptococcus sanguinis, present in the biofilm colonizing human tooth surfaces, may be beneficial in the oral cavity, though it also serves as a causative agent of an extra-oral disease, infective endocarditis. Previous mutagenesis of lipoprotein genes from S. sanguinis strain SK36 identified the SsaB gene as necessary for virulence in a rabbit model of endocarditis. Based on homology, we suspected that SsaB was a metal transporter. A procedure utilizing inductively coupled plasma optical emission spectrometry was optimized and implemented for determination of the concentrations (μg metal per mg of cellular protein) of 17 metals in SK36 and ssaB mutant cell lysates. Data revealed that the ssaB mutant reproducibly accumulated lower concentrations of both manganese and iron, but showed no significant difference in accumulated concentrations of magnesium, or any of 14 additional metals for which there were standards, or in signal intensities for 60 other elements analyzed for which there were no standards. This data suggested that SsaB binds both manganese and iron to facilitate transport. When grown in brain-heart infusion (BHI) broth, both strains accumulated more iron than manganese. To assess whether this was due entirely to the higher concentration of iron relative to manganese in BHI broth, SK36 and the ssaB mutant were grown in all-purpose tween (APT) broth, rich in both metals. Both strains accumulated more manganese than iron in APT broth. Higher accumulation of manganese in APT broth compared to BHI broth for both strains suggested that manganese is accumulated through both SsaB-dependent and SsaB-independent mechanisms. Relative cellular abundance of iron and manganese in S. sanguinis varies dramatically depending on relative abundance in the growth medium, highlighting the importance of using physiologically relevant media in future studies. This data also implies that S. sanguinis is flexible in its metal requirements and is rather efficient in sequestering iron, which would otherwise react with cellular hydrogen peroxide to produce DNA-damaging hydroxyl radicals.https://scholarscompass.vcu.edu/uresposters/1061/thumbnail.jp

Materials for use in intercultural education in grades ix and x

Thesis (M.A.)--Boston University, 1946. This item was digitized by the Internet Archive

The Realities of the Most Powerful Office in the World: A Comparison Between Public Opinion and the Legal Underpinning for Executive Action in U.S. Foreign Affairs

This paper explores the relationship between public opinion data and the consequent policy decisions enacted by the federal government. Specifically, it will examine President Trump’s policy implementations regarding the United States’ role in foreign affairs. Multiple public opinion polls, both domestic and international, will be utilized throughout to establish an understanding of the public’s complex views of this role. Antecedent to this, however, the nature of public opinion will be reviewed by providing a definition for public opinion, examining the various influences throughout one’s life, evaluating the criticisms and problems associated with it, and understanding how it ultimately relates to policy making. Significant policy decisions executed by President Trump will be discussed, including the Paris Agreement, North American Free Trade Agreement (NAFTA), and Iran nuclear deal. His continually developing relationships with nations such as Russia, North Korea, and China will also be examined. Notable legal cases involving executive orders issued by President Trump will be assessed, namely the “Travel Ban,” family separations, and the Flores Settlement Agreement (FSA). Through in-depth analysis, the paper will illustrate that public opinion, especially among American citizens, does not significantly affect President Trump’s decision making when leading the United States in world affairs

Information system for operation analysis of time series

This work is devoted to modern information technology of operational analysis of time series. The main purpose of data operational analysis is replenishment, data blurring, smoothing and forecasting of time series, obtaining conclusions about periodicity, cyclicity, character of the behavior of the observed process. Also attention is paid to the task of separating noise or observational errors from real data

A new pseudopolymorph of 5,11,17,23,29,35,41,47-octabromo-49,50,51,52,53, 54,55,56-octamethoxycalix[8]arene

Crystals of the title calixarene containing CCl4 as solvent have already been investigated [Baudry, Felix, Bavoux, Perrin, Vocanson, Dumazet-Bonnamour & Lamartine (2003). New J. Chem. pp. 1540-1543]. We present here a new pseudopolymorph of this compound, C64H 56Br8O8·2C4H8O, containing tetrahydrofuran as solvent and crystallizing in a different space group. However, the molecular conformation of both molecules is very similar. Further similarities of both structures are that the calixarene molecules are located on a centre of inversion and that the solvent molecules occupy similar positions with respect to the calixarene molecules. © 2003 International Union of Crystallography Printed in Great Britain - all rights reserved