Secreted Bacterial Vesicles as Good Samaritans

Bacteriodes fragilis and polysaccharide A capsular antigen (PSA) produced by this commensal bacteria can mediate immune tolerance in the gastrointestinal (GI) tract. When looking for naturally secreted forms of PSA, Shen et al. (2012) suprisingly found that PSA is packaged in outer membrane vesicles (OMVs), bacterial blebs with a disreputable past

Pseudomonas aeruginosa vesicles associate with and are internalized by human lung epithelial cells

<p>Abstract</p> <p>Background</p> <p><it>Pseudomonas aeruginosa </it>is the major pathogen associated with chronic and ultimately fatal lung infections in patients with cystic fibrosis (CF). To investigate how <it>P. aeruginosa</it>-derived vesicles may contribute to lung disease, we explored their ability to associate with human lung cells.</p> <p>Results</p> <p>Purified vesicles associated with lung cells and were internalized in a time- and dose-dependent manner. Vesicles from a CF isolate exhibited a 3- to 4-fold greater association with lung cells than vesicles from the lab strain PAO1. Vesicle internalization was temperature-dependent and was inhibited by hypertonic sucrose and cyclodextrins. Surface-bound vesicles rarely colocalized with clathrin. Internalized vesicles colocalized with the endoplasmic reticulum (ER) marker, TRAPα, as well as with ER-localized pools of cholera toxin and transferrin. CF isolates of <it>P. aeruginosa </it>abundantly secrete PaAP (PA2939), an aminopeptidase that associates with the surface of vesicles. Vesicles from a PaAP knockout strain exhibited a 40% decrease in cell association. Likewise, vesicles from PAO1 overexpressing PaAP displayed a significant increase in cell association.</p> <p>Conclusion</p> <p>These data reveal that PaAP promotes the association of vesicles with lung cells. Taken together, these results suggest that <it>P. aeruginosa </it>vesicles can interact with and be internalized by lung epithelial cells and contribute to the inflammatory response during infection.</p

Contribution of bacterial outer membrane vesicles to innate bacterial defense

<p>Abstract</p> <p>Background</p> <p>Outer membrane vesicles (OMVs) are constitutively produced by Gram-negative bacteria throughout growth and have proposed roles in virulence, inflammation, and the response to envelope stress. Here we investigate outer membrane vesiculation as a bacterial mechanism for immediate short-term protection against outer membrane acting stressors. Antimicrobial peptides as well as bacteriophage were used to examine the effectiveness of OMV protection.</p> <p>Results</p> <p>We found that a hyper-vesiculating mutant of <it>Escherichia coli </it>survived treatment by antimicrobial peptides (AMPs) polymyxin B and colistin better than the wild-type. Supplementation of <it>E. coli </it>cultures with purified outer membrane vesicles provided substantial protection against AMPs, and AMPs significantly induced vesiculation. Vesicle-mediated protection and induction of vesiculation were also observed for a human pathogen, enterotoxigenic <it>E. coli </it>(ETEC), challenged with polymyxin B. When ETEC with was incubated with low concentrations of vesicles concomitant with polymyxin B treatment, bacterial survival increased immediately, and the culture gained resistance to polymyxin B. By contrast, high levels of vesicles also provided immediate protection but prevented acquisition of resistance. Co-incubation of T4 bacteriophage and OMVs showed fast, irreversible binding. The efficiency of T4 infection was significantly reduced by the formation of complexes with the OMVs.</p> <p>Conclusions</p> <p>These data reveal a role for OMVs in contributing to innate bacterial defense by adsorption of antimicrobial peptides and bacteriophage. Given the increase in vesiculation in response to the antimicrobial peptides, and loss in efficiency of infection with the T4-OMV complex, we conclude that OMV production may be an important factor in neutralizing environmental agents that target the outer membrane of Gram-negative bacteria.</p

Pengembangan Lembar Kegiatan Siswa Berbasis Pendekatan Saintifik pada Materi Pencatatan Transaksi Perusahaan Manufaktur

The purpose of this research is to produce a student worksheet based on scientific approach in the material of transaction bookkeeping of manufacture company, to determine the feasibility, and to know the students' response of the worksheet. This research uses the Thiagarajan 4-D development model. However this research is limited only to development phase. The result shows that the student worksheet that has been developed based on scientific approach is very feasible to be used in learning process, which based on the feasibility of its content, presentation, language, and graphic. The overall feasibility validation result of the student worksheet of the 4 components from the experts have the average score of 89%. The closed test result shows that the product of scientific approach based student worksheet gained a very good response from the students with the percentage of 96.3%

Time-dependent Density Functional calculation of e-H scattering

Phase shifts for single-channel elastic electron-atom scattering are derived from time-dependent density functional theory. The H$^-$ ion is placed in a spherical box, its discrete spectrum found, and phase shifts deduced. Exact-exchange yields an excellent approximation to the ground-state Kohn-Sham potential, while the adiabatic local density approximation yields good singlet and triplet phase shifts.Comment: 5 pages, 4 figures, 1 tabl

‘It is not fashionable to suffer nowadays’: Community motivations to repeatedly participate in outreach HIV testing indicate UHC potential in Tanzania

OBJECTIVE: This study examined people’s motivations for (repeatedly) utilizing HIV testing services during community-based testing events in urban and rural Shinyanga, Tanzania and potential implications for Universal Health Coverage (UHC). METHODS: As part of a broader multidisciplinary study on the implementation of a HIV Test and Treat model in Shinyanga Region, Tanzania, this ethnographic study focused on community-based testing campaigns organised by the implementing partner. Between April 2018 and December 2019, we conducted structured observations (24), short questionnaires (42) and in-depth interviews with HIV-positive (23) and HIV-negative clients (8). Observations focused on motivations for (re-)testing, and the counselling and testing process. Thematic analysis based on inductive and deductive coding was completed using NVivo software. RESULTS: Regular HIV testing was encouraged by counsellors. Most participants in testing campaigns were HIV-negative; 51.1% had tested more than once over their lifetimes. Testing campaigns provided an accessible way to learn one’s HIV status. Motivations for repeat testing included: monitoring personal health to achieve (temporary) reassurance, having low levels of trust toward sexual partners, feeling at risk, seeking proof of (ill)-health, and acting responsibly. Repeat testers also associated testing with a desire to start treatment early to preserve a healthy-looking body, should they prove HIV positive. CONCLUSIONS: Community-based testing campaigns serve three valuable functions related to HIV prevention and treatment: 1) enable community members to check their HIV status regularly as part of a personalized prevention strategy that reinforces responsible behaviour; 2) identify recently sero-converted clients who would not otherwise be targeted; and 3) engage community with general prevention and care messaging and services. This model could be expanded to include routine management of other (chronic) diseases and provide an entry for scaling up UHC

The relationship between primary school leaders' utilization of distributed leadership and teachers' capacity to change

Although it is generally known that distributed leadership is relevant for reinforcing teachers' capacity to change, how leadership roles are distributed among teachers largely depends on how principals perceive distributed leadership. Specifying principals' perceptions and how these are related to teachers' capacity to change leads to theories about the knowledge and beliefs of leaders with regard to distributed leadership that are crucial for achieving educational change as a team. Combining questionnaire data from 787 Dutch primary school teachers and interview data from 58 principals in a parallel mixed methods design, this study shows differences in how school leaders distribute leadership roles. In addition, the results indicate that several aspects of teachers' capacity to change, namely, joint work, collegial support, knowledge sharing, self-efficacy and their internalization of school goals, are more present in schools in which school leaders distribute leadership among teachers than in schools in which they do not

Pengaruh warna led berkedip yang berbeda terhadap hasil tangkapan pancing cumi-cumi di perairan Tahuna Kelurahan Santiago Kabupaten Kepulauan Sangihe

Rendahnya tangkapan cumi dengan menggunakan alat tangkap tradisional telah menjadi masalah selama puluhan tahun di Kelurahan Santiago Kepulauan sangihe sehingga sangat menuntut aplikasi metode penangkapan baru. Salah satu metode modifikasi terbaik untuk menarik ikan dan meningkatkan hasil tangkapan ialah dengan menggunakan cahaya buatan. Tujuan dari penelitian ini adalah untuk mempelajari pengaruh iluminasi warna cahaya lampu light emitting diode (LED) terhadap jumlah dan rerata tangkapan cumi-cumi. Kombinasi empat cahaya berbeda dirancang dan dianalisa menggunakan  Rancangan Bujur Sangkar Latin (RBSL). Hasil penelitian menunjukkan pengaruh tak nyata dari iluminasi warna hijau dan merah tetapi pengaruh sangat nyata (tertinggi) dari iluminasi warna putih dan biru terhadap hasil tangkapan cumi-cumi

A compilation, tabulation and analysis of spelling errors made by pupils in grades four, five, and six in free writing of sentences using given stimuli words

Thesis (M.A.)--Boston Universit