Locking down SOS Mutagenesis Repression in a Dynamic Pathogen.

The article "The DdrR coregulator of the Acinetobacter baumannii mutagenic DNA damage response potentiates UmuDAb repression of error-prone polymerases" in this issue of the J Bacteriol, (D. Cook, M. D.

Situating Second-Year Success: Understanding Second-Year STEM Experiences at a Liberal Arts College.

Challenges particular to second-year students have been identified that can impact persistence in science, technology, engineering, and mathematics (STEM) fields. We implemented a program to improve student success in intermediate-level science courses by helping students to feel they belonged and could succeed in STEM. We used survey measures of perceptions and attitudes and then qualitative measures to characterize the impact of support strategies, including peer mentoring, a second-year science student retreat, learning and advising support resources, and department-specific activities.

Principles and Practices Fostering Inclusive Excellence: Lessons from the Howard Hughes Medical Institute's Capstone Institutions.

Best-practices pedagogy in science, technology, engineering, and mathematics (STEM) aims for inclusive excellence that fosters student persistence. This paper describes principles of inclusivity across 11 primarily undergraduate institutions designated as Capstone Awardees in Howard Hughes Medical Institute's (HHMI) 2012 competition. The Capstones represent a range of institutional missions, student profiles, and geographical locations.

Sensitivity of an Acinetobacter baylyi mpl mutant to DNA damage.

A mutant derived from Acinetobacter baylyi ADP1 was isolated from a screen for genes involved in the response to DNA damage. This derivative has an insertion in the mpl gene which encodes a peptidoglycan-recycling protein. We demonstrate that the insertion renders cells sensitive to mitomycin C and to UV.

A constitutively expressed, truncated umuDC operon regulates the recA-dependent DNA damage induction of a gene in Acinetobacter baylyi strain ADP1.

In response to environmentally caused DNA damage, SOS genes are up-regulated due to RecA-mediated relief of LexA repression. In Escherichia coli, the SOS umuDC operon is required for DNA damage checkpoint functions and for replicating damaged DNA in the error-prone process called SOS mutagenesis. In the model soil bacterium Acinetobacter baylyi strain ADP1, however, the content, regulation, and function of the umuDC operon are unusual.

The expression of the Acinetobacter calcoaceticus recA gene increases in response to DNA damage independently of RecA and of development of competence for natural transformation.

Using the lacZ operon fusion technique, the transcriptional control of the Acinetobacter calcoaceticus recA gene was studied. A low (approximately twofold) inductive capacity was observed for compounds that damage DNA and/or inhibit DNA replication, e.g.