Served Through Service: Undergraduate Students’ Experiences in Community Engaged Learning at a Catholic and Marianist University

Students participating in sustained community service at an urban Catholic and Marianist university were volunteer informants in this qualitative exploration of the meaning they make of their service experiences. A PhD student research team (nine members) interviewed fourteen undergraduate students (eleven of whom were seniors). Findings were organized as themes constructed within three domains: background, experience, and meaning. Within “background,” students who had prior work in faith-based service before college deepened their meaning of service. Within “experience,” there were social and cultural dynamics of navigating on and off campus life, including the roles students played as well as the challenge of time management. Within “meaning,” building relationships was central to community service. Students built strong personal relationships with and deep commitments to city residents; the meaning of their own identities grew and developed. Experiencing the roots of social injustice led students both to confirm and to reconsider their life vocations

Served Through Service: Undergraduate Students’ Experiences in Community Engaged Learning at a Catholic and Marianist University

Students participating in sustained community service at an urban Catholic and Marianist university were volunteer informants in this qualitative exploration of the meaning they make of their service experiences. A PhD student research team (nine members) interviewed fourteen undergraduate students (eleven of whom were seniors). Findings were organized as themes constructed within three domains: background, experience, and meaning. Within “background,” students who had prior work in faith-based service before college deepened their meaning of service. Within “experience,” there were social and cultural dynamics of navigating on and off campus life, including the roles students played as well as the challenge of time management. Within “meaning,” building relationships was central to community service. Students built strong personal relationships with and deep commitments to city residents; the meaning of their own identities grew and developed. Experiencing the roots of social injustice led students both to confirm and to reconsider their life vocations. Estudiantes que participaban en servicios continuados a la comunidad en una universidad católica marianista urbana participaron como encuestados voluntarios de esta exploración cualitativa del significado que le dan a sus experiencias de servicio. Un equipo de investigación de estudiantes (nueve) de doctorado entrevistaron a catorce estudiantes de licenciatura (de los cuales 10 eran de último curso). Los resultados se organizaron en temas englobados en tres dominios: antecedentes, experiencia y significado. En “antecedentes”, los estudiantes que habían realizado trabajo previo en servicios religiosos antes de la universidad profundizaron su significado de servicio. Dentro de “experiencia”, hubo dinámicas sociales y culturales que navegaban dentro y fuera de la vida en el campus, desde el papel de los estudiantes hasta el reto de la gestión del tiempo. En “significado”, la construcción de relaciones resultó central para los servicios a la comunidad. Los estudiantes cultivaron fuertes relaciones personales y compromisos profundos con los residentes de la ciudad. El significado de su propia identidad creció y se desarrolló. Experimentar las raíces de la injusticia social orientó a los estudiantes a confirmar y reconsiderar su vocación y elección de vida. Palabras clave: servicio, aprendizaje a través del servicio, aprendizaje-servicio, aprendizaje comprometido con la comunidad, liderazgo estudiantil, estudiante de licenciatur

Structural basis for CRISPR RNA-guided DNA recognition by Cascade

The CRISPR (clustered regularly interspaced short palindromic repeats) immune system in prokaryotes uses small guide RNAs to neutralize invading viruses and plasmids. In Escherichia coli, immunity depends on a ribonucleoprotein complex called Cascade. Here we present the composition and low-resolution structure of Cascade and show how it recognizes double-stranded DNA (dsDNA) targets in a sequence-specific manner. Cascade is a 405-kDa complex comprising five functionally essential CRISPR-associated (Cas) proteins (CasA1B2C6D1E1) and a 61-nucleotide CRISPR RNA (crRNA) with 5′-hydroxyl and 2′,3′-cyclic phosphate termini. The crRNA guides Cascade to dsDNA target sequences by forming base pairs with the complementary DNA strand while displacing the noncomplementary strand to form an R-loop. Cascade recognizes target DNA without consuming ATP, which suggests that continuous invader DNA surveillance takes place without energy investment. The structure of Cascade shows an unusual seahorse shape that undergoes conformational changes when it binds target DNA.

Regulation of the vapBC-1 Toxin-Antitoxin Locus in Nontypeable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi) are human-adapted commensal bacteria that can cause a number of chronic mucosal infections, including otitis media and bronchitis. One way for these organisms to survive antibiotic therapy and cause recurrent disease is to stop replicating, as most antimicrobials target essential biosynthetic pathways. Toxin-antitoxin (TA) gene pairs have been shown to facilitate entry into a reversible bacteriostatic state. Characteristically, these operons encode a protein toxin and an antitoxin that associate following translation to form a nontoxic complex, which then binds to and regulates the cognate TA promoter. Under stressful conditions, the labile antitoxin is degraded and the complex disintegrates, freeing the stable toxin to facilitate growth arrest. How these events affected the regulation of the TA locus, as well as how the transcription of the operon was subsequently returned to its normal state upon resumption of growth, was not fully understood. Here we show that expression of the NTHi vapBC-1 TA locus is repressed by a complex of VapB-1 and VapC-1 under conditions favorable for growth, and activated by the global transactivator Factor for Inversion Stimulation (Fis) upon nutrient upshift from stationary phase. Further, we demonstrate for the first time that the VapC-1 toxin alone can bind to its cognate TA locus control region and that the presence of VapB-1 directs the binding of the VapBC-1 complex in the transcriptional regulation of vapBC-1

A hyper-mutant of the unusual σ70-Pr promoter bypasses synergistic ppGpp/DksA co-stimulation

The activities of promoters can be temporally and conditionally regulated by mechanisms other than classical DNA-binding repressors and activators. One example is the inherently weak σ70-dependent Pr promoter that ultimately controls catabolism of phenolic compounds. The activity of Pr is up-regulated through the joint action of ppGpp and DksA that enhance the performance of RNA polymerase at this promoter. Here, we report a mutagenesis analysis that revealed substantial differences between Pr and other ppGpp/DksA co-stimulated promoters. In vitro transcription and RNA polymerase binding assays show that it is the T at the −11 position of the extremely suboptimal −10 element of Pr that underlies both poor binding of σ70-RNAP and a slow rate of open complex formation—the process that is accelerated by ppGpp and DksA. Our findings support the idea that collaborative action of ppGpp and DksA lowers the rate-limiting transition energy required for conversion between intermediates on the road to open complex formation