Bostonia. Volume 16

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Actinobacillus pleuropneumoniae induces SJPL cell cycle arrest in G2/M-phase and inhibits porcine reproductive and respiratory syndrome virus replication

Background: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry and causes important economic losses. No effective antiviral drugs against it are commercially available. We recently reported that the culture supernatant of Actinobacillus pleuropneumoniae, the porcine pleuropneumonia causative agent, has an antiviral activity in vitro against PRRSV in SJPL cells. Objectives of this study were (i) to identify the mechanism behind the antiviral activity displayed by A. pleuropneumoniae and (ii) to characterize the active molecules present in the bacterial culture supernatant. Methods: Antibody microarray analysis was used in order to point out cellular pathways modulated by the A. pleuropneumoniae supernatant. Subsequent, flow cytometry analysis and cell cycle inhibitors were used to confirm antibody microarray data and to link them to the antiviral activity of the A. pleuropneumoniae supernatant. Finally, A. pleuropneumoniae supernatant characterization was partially achieved using mass spectrometry. Results: Using antibody microarray, we observed modulations in G2/M-phase cell cycle regulation pathway when SJPL cells were treated with A. pleuropneumoniae culture supernatant. These modulations were confirmed by a cell cycle arrest at the G2/M-phase when cells were treated with the A. pleuropneumoniae culture supernatant. Furthermore, two G2/M-phase cell cycle inhibitors demonstrated the ability to inhibit PRRSV infection, indicating a potential key role for PRRSV infection. Finally, mass spectrometry lead to identify two molecules (m/z 515.2 and m/z 663.6) present only in the culture supernatant. Conclusions: We demonstrated for the first time that A. pleuropneumoniae is able to disrupt SJPL cell cycle resulting in inhibitory activity against PRRSV. Furthermore, two putative molecules were identified from the culture supernatant. This study highlighted the cell cycle importance for PRRSV and will allow the development of new prophylactic or therapeutic approaches against PRRSV

Impact of Actinobacillus pleuropneumoniae biofilm mode of growth on the lipid A structures and stimulation of immune cells

Actinobacillus pleuropneumoniae (APP), the etiologic agent of porcine pleuropneumonia, forms biofilms on biotic and abiotic surfaces. APP biofilms confers resistance to antibiotics. To our knowledge, no studies have examined the role of APP biofilm in immune evasion and infection persistence. This study was undertaken to (i) investigate biofilm-associated LPS modifications occurring during the switch to biofilm mode of growth; and (ii) characterize pro-inflammatory cytokines expression in porcine pulmonary alveolar macrophages (PAMs) and proliferation in porcine PBMCs challenged with planktonic or biofilm APP cells. Extracted lipid A samples from biofilm and planktonic cultures were analyzed by HPLC high-resolution, accurate mass spectrometry. Biofilm cells displayed significant changes in lipid A profiles when compared with their planktonic counterparts. Furthermore, in vitro experiments were conducted to examine the inflammatory response of PAMs exposed to UV-inactivated APP grown in biofilm or in suspension. Relative mRNA expression of pro-inflammatory genes IL1, IL6, IL8 and MCP1 decreased in PAMs when exposed to biofilm cells compared to planktonic cells. Additionally, the biofilm state reduced PBMCs proliferation. Taken together, APP biofilm cells show a weaker ability to stimulate innate immune cells, which could be due, in part, to lipid A structure modifications

Editor\u27s Corner - New Assistant Editors

It is a special pleasure to introduce two new assistant editors in the physical sciences. Chemistry and physics articles have not been abundant in recent issues and both editors are particularly interested in locating articles of practical value to classroom teachers. As each of the new editors states in his editorial, many readers have excellent ideas for classroom activities. Some of these activities may not be totally new but have a new approach which will prove helpful to other teachers. The entire editorial staff is eager to aid you in preparing articles for publication. Contact one of the editors to help you share your ideas with the profession

The Transit Light Curve (TLC) Project. I. Four Consecutive Transits of the Exoplanet XO-1b

We present RIz photometry of four consecutive transits of the newly discovered exoplanet XO-1b. We improve upon the estimates of the transit parameters, finding the planetary radius to be R_P = 1.184 +0.028/-0.018 R_Jupiter and the stellar radius to be R_S = 0.928 +0.018/-0.013 R_Sun, assuming a stellar mass of M_S = 1.00 +/- 0.03 M_Sun. The uncertainties in the planetary and stellar radii are dominated by the uncertainty in the stellar mass. These uncertainties increase by a factor of 2-3 if a more conservative uncertainty of 0.10 M_Sun is assumed for the stellar mass. Our estimate of the planetary radius is smaller than that reported by McCullough et al. (2006) and yields a mean density that is comparable to that of TrES-1 and HD 189733b. The timings of the transits have an accuracy ranging from 0.2 to 2.5 minutes, and are marginally consistent with a uniform period.Comment: 22 pages, 5 figures, 2 tables. Accepted for publication in Ap

Mass and radius determinations for five transiting M-dwarf stars

We have derived masses and radii for both components in five short-period single-lined eclipsing binary stars discovered by the TrES wide-angle photometric survey for transiting planets. All these systems consist of a visible F-star primary and an unseen M-star secondary (M_A > 0.8 M_sun, M_B < 0.45 M_sun). The spectroscopic orbital solution combined with a high precision transit light curve for each system gives sufficient information to calculate the density of the primary star and the surface gravity of the secondary. The masses of the primary stars were obtained using stellar evolution models. The solutions were compared with results obtained by calculating the radius of the primary stars under the assumption of rotational synchronization with the orbital period and alignment between their spin axis and the axis of the orbit. Four systems show an acceptable match between the two sets of results, but one system shows a clear mismatch between the two solutions, which may indicate the absence of synchronization or a misalignment between the rotational and orbital axis. When compared to low-mass stellar evolution models, the derived masses and radii of the unseen M dwarfs are inconsistent (three only marginally) with the predicted values, with all of the radii being larger than expected for their masses. These results confirm the discrepancy shown in previous work between the predicted and observed radii on low-mass binary stars. This work also shows that reliance on the assumption of synchronization to derive the mass and radius of stars in eclipsing single--lined F+M binaries is a useful tool, but may not always be warranted and should be carefully tested against stellar evolution models.Comment: 36 pages: 20 pages of text, 13 tables, 7 figures. Accepted for publication in Ap

Cost and feasibility: an exploratory case study comparing use of a literature review method with questionnaires, interviews and focus groups to identify barriers for a behaviour-change intervention

Background: It is often recommended that behaviour-change interventions be tailored to barriers. There is a scarcity of research into the best method of barrier identification, although combining methods has been suggested to be beneficial. This paper compares the feasibility and costs of three different methods of barrier identification used in three implementation projects conducted in primary care. Methods: Underpinned by a theory-base, project one used a questionnaire and interviews; project two used a single focus group and questionnaire, and project three used a literature review of published barriers. The feasibility of each project, as experienced by the research team, and labour costs are summarised. Results: The literature review of published barriers was the least costly and most feasible method, being quick to conduct and avoiding the challenges of recruitment experienced when using interviews or a questionnaire. The feasibility of using questionnaires was further reduced by the time taken develop the instruments. Conducting a single focus group was also found to be a more feasible method, taking less time than interviews to collect and analyse the barriers. Conclusions: Considering the ease of recruitment, time required and cost of the different methods to collect barriers is crucial at the start of implementation studies. The literature review method is the least costly and most feasible method. Use of a single focus group was found to be more feasible than conducting individual interviews or administering a questionnaire, with less recruitment challenges experienced, and quicker data collection. Future research would benefit from comparing the robustness of the methods in terms of the comprehensiveness of barriers identified

Improving the normalization of complex interventions: measure development based on normalization process theory (NoMAD): study protocol

&lt;b&gt;Background&lt;/b&gt; Understanding implementation processes is key to ensuring that complex interventions in healthcare are taken up in practice and thus maximize intended benefits for service provision and (ultimately) care to patients. Normalization Process Theory (NPT) provides a framework for understanding how a new intervention becomes part of normal practice. This study aims to develop and validate simple generic tools derived from NPT, to be used to improve the implementation of complex healthcare interventions.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Objectives&lt;/b&gt; The objectives of this study are to: develop a set of NPT-based measures and formatively evaluate their use for identifying implementation problems and monitoring progress; conduct preliminary evaluation of these measures across a range of interventions and contexts, and identify factors that affect this process; explore the utility of these measures for predicting outcomes; and develop an online users’ manual for the measures.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt; A combination of qualitative (workshops, item development, user feedback, cognitive interviews) and quantitative (survey) methods will be used to develop NPT measures, and test the utility of the measures in six healthcare intervention settings.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Discussion&lt;/b&gt; The measures developed in the study will be available for use by those involved in planning, implementing, and evaluating complex interventions in healthcare and have the potential to enhance the chances of their implementation, leading to sustained changes in working practices

The crystal structure of stichtite, re-examination of barbertonite, and the nature of polytypism in MgCr hydrotalcites

abStraCt Stichtite, ideally Mg 6 Cr 2 CO 3 (OH) 16 •4H 2 O, from Stichtite Hill, Tasmania, Australia, and barbertonite, also ideally Mg 6 Cr 2 CO 3 (OH) 16 •4H 2 O, from the Kaapsehoop asbestos mine, South Africa, have been studied by powder X-ray diffraction and their structures have been refined using the Rietveld method. Stichtite from Stichtite Hill crystallizes in the rhombohedral space group R3m, with unitcell parameters a = 3.09575(3) and c = 23.5069(6) Å, V = 195.099(6) Å 3 , with Z = 3/8. Barbertonite from the Kaapsehoop asbestos mine crystallizes in the hexagonal space group P6 3 /mmc. The co-type specimens of barbertonite were found to be intergrown mixtures consisting of barbertonite and stichtite. Unit-cell parameters of barbertonite from the co-type specimens were a = 3.09689(6), c = 15.6193(8) Å, and V = 129.731(8) Å 3 and a = 3.09646(6), c = 15.627(1) Å V = 129.76(1) Å 3 , and Z = ¼. Rietveld refinements of both stichtite and barbertonite show that they are polytypes rather than polymorphs and do not represent distinct mineral species. Several possible nomenclature systems are discussed for the naming of hydrotalcite minerals and groups. Raman band assignments are also presented for stichtite from Stichtite Hill. Stichtite and hydrotalcite minerals make up a large proportion of the ore at the Mount Keith nickel mine in Western Australia. Bulk powder diffraction shows the ore contains 6.1 wt% stichtite and 5.6 wt% iowaite. Hydrotalcite group minerals provide an important potential reservoir of CO 2 . At Mount Keith, the amount of CO 2 mined as stichtite could exceed 45 000 metric tons per year, while exchange of Cl for CO 3 could fix in excess of 40 000 metric tons CO 2 per year if end-member iowaite is reacted to form pyaroaurite