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Full-Text Articles in Life Sciences

H-Ns, Its Family Members And Their Regulation Of Virulence Genes In Shigella Species, Michael A. Picker, Helen J. Wing Dec 2016

H-Ns, Its Family Members And Their Regulation Of Virulence Genes In Shigella Species, Michael A. Picker, Helen J. Wing

Life Sciences Faculty Research

The histone-like nucleoid structuring protein (H-NS) has played a key role in shaping the evolution of Shigella spp., and provides the backdrop to the regulatory cascade that controls virulence by silencing many genes found on the large virulence plasmid. H-NS and its paralogue StpA are present in all four Shigella spp., but a second H-NS paralogue, Sfh, is found in the Shigella flexneri type strain 2457T, which is routinely used in studies of Shigella pathogenesis. While StpA and Sfh have been proposed to serve as “molecular backups” for H-NS, the apparent redundancy of these proteins is questioned by in vitro …


Comparative Genomics Of 9 Novel Paenibacillus Larvae Bacteriophages, Casey Stamereilers, Lucy Leblanc, Diane Yost, Penny S. Amy, Philippos K. Tsourkas Aug 2016

Comparative Genomics Of 9 Novel Paenibacillus Larvae Bacteriophages, Casey Stamereilers, Lucy Leblanc, Diane Yost, Penny S. Amy, Philippos K. Tsourkas

Life Sciences Faculty Research

American Foulbrood Disease, caused by the bacterium Paenibacillus larvae, is one of the most destructive diseases of the honeybee, Apis mellifera. Our group recently published the sequences of 9 new phages with the ability to infect and lyse P. larvae. Here, we characterize the genomes of these P. larvae phages, compare them to each other and to other sequenced P. larvae phages, and putatively identify protein function. The phage genomes are 38–45 kb in size and contain 68–86 genes, most of which appear to be unique to P. larvae phages. We classify P. larvae phages into 2 main clusters and …


Stationary-Phase Mutagenesis In Stressed Bacillus Subtilis Cells Operates By Mfd-Dependent Mutagenic Pathways, Martha Gómez-Marroquín, Holly A. Martin, Amber Pepper, Mary E. Girard, Amanda Kidman, Carmen Vallin, Ronald E. Yasbin, Mario Pedraza-Reyes, Eduardo Robleto Jul 2016

Stationary-Phase Mutagenesis In Stressed Bacillus Subtilis Cells Operates By Mfd-Dependent Mutagenic Pathways, Martha Gómez-Marroquín, Holly A. Martin, Amber Pepper, Mary E. Girard, Amanda Kidman, Carmen Vallin, Ronald E. Yasbin, Mario Pedraza-Reyes, Eduardo Robleto

Life Sciences Faculty Research

In replication-limited cells of Bacillus subtilis, Mfd is mutagenic at highly transcribed regions, even in the absence of bulky DNA lesions. However, the mechanism leading to increased mutagenesis through Mfd remains currently unknown. Here, we report that Mfd may promote mutagenesis in nutritionally stressed B. subtilis cells by coordinating error-prone repair events mediated by UvrA, MutY and PolI. Using a point-mutated gene conferring leucine auxotrophy as a genetic marker, it was found that the absence of UvrA reduced the Leu+ revertants and that a second mutation in mfd reduced mutagenesis further. Moreover, the mfd and polA mutants presented low but …


Status And Management Of Non-Native Plant Invasion In Three Of The Largest National Parks In The United States, Scott R. Abella, Nicholas A. Fisichelli, Sarah M. Schmid, Teague M. Embrey, Debra Hughson, Jane Cipra Jun 2016

Status And Management Of Non-Native Plant Invasion In Three Of The Largest National Parks In The United States, Scott R. Abella, Nicholas A. Fisichelli, Sarah M. Schmid, Teague M. Embrey, Debra Hughson, Jane Cipra

Life Sciences Faculty Research

Globally, invasion by non-native plants threatens resources that nature reserves are designated to protect. We assessed the status of non-native plant invasion on 1,662, 0.1-ha plots in Death Valley National Park, Mojave National Preserve, and Lake Mead National Recreation Area. These parks comprise 2.5 million ha, 23% of the national park land in the contiguous USA. At least one non-native species inhabited 82% of plots. Thirty-one percent of plots contained one non-native species, 30% two, 17% three, and 4% four to ten non-native species. Red brome (Bromus rubens), an ‘ecosystem engineer’ that alters fire regimes, was most widespread, …


Rapidly Restoring Biological Soil Crusts And Ecosystem Functions In A Severely Disturbed Desert Ecosystem, Lindsay P. Chiquoine, Scott R. Abella, Matthew A. Bowker Jun 2016

Rapidly Restoring Biological Soil Crusts And Ecosystem Functions In A Severely Disturbed Desert Ecosystem, Lindsay P. Chiquoine, Scott R. Abella, Matthew A. Bowker

Life Sciences Faculty Research

Restoring biological soil crusts (biocrusts) in degraded drylands can contribute to recovery of ecosystem functions that have global implications, including erosion resistance and nutrient cycling. To examine techniques for restoring biocrusts, we conducted a replicated, factorial experiment on recently abandoned road surfaces by applying biocrust inoculation (salvaged and stored dry for two years), salvaged topsoil, an abiotic soil amendment (wood shavings), and planting of a dominant perennial shrub (Ambrosia dumosa). Eighteen months after treatments, we measured biocrust abundance and species composition, soil chlorophyll a content and fertility, and soil resistance to erosion. Biocrust addition significantly accelerated biocrust recovery on disturbed …