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Full-Text Articles in Life Sciences

Stationary Phase Mutagenesis In Bacillus Subtilis: The Interaction Between Transcription And Error-Prone Replication In Conditions Of Stress, Mary Girard, Eduardo Robleto Aug 2009

Stationary Phase Mutagenesis In Bacillus Subtilis: The Interaction Between Transcription And Error-Prone Replication In Conditions Of Stress, Mary Girard, Eduardo Robleto

Undergraduate Research Opportunities Program (UROP)

While under conditions of stress, non-dividing cells may acquire beneficial mutations. This is referred to as stationary phase mutagenesis, or adaptive mutagenesis. Previous research has shown that actively transcribed genes and those under selective pressure are prone to mutations that confer escape from non-dividing conditions. Accordingly, strains lacking transcription factors have shown a drastically lower number of mutations that confer escape while under amino acid starvation than those observed in the wildtype background. Also, error-prone DNA polymerases are known to be active in cells under stress and it has been shown that strains lacking an error-prone DNA polymerase display reduced …


The Role Of Rpoe In Stationary Phase Mutagenesis In Bacillus, Turquoise C. Alexander, Eduardo A. Robleto Aug 2009

The Role Of Rpoe In Stationary Phase Mutagenesis In Bacillus, Turquoise C. Alexander, Eduardo A. Robleto

Undergraduate Research Opportunities Program (UROP)

Stationary phase mutagenesis is a phenomenon whereby random mutations are generated in non-dividing cells. In order to understand how these mutations arise, we use Bacillus subtilis, a gram positive rod-shaped model organism. It is hypothesize that increased transcription promotes stationary phase mutagenesis in this organism. We therefore examined the role of rpoE, a gene that encodes RNA polymerase ! subunit and proposed to influence efficiency of transcription. To this end, we will first generate a strain bearing a deletion in the rpoE gene. In order to determine if this gene is important for mutagenesis, we will examine the accumulation of …


The Role Of Recn In Stationary Phase Mutagenesis In Bacillus Subtilis, Lauren E. Johnson, Katherine R. Ona, Eduardo A. Robleto, Ronald E. Yasbin Aug 2009

The Role Of Recn In Stationary Phase Mutagenesis In Bacillus Subtilis, Lauren E. Johnson, Katherine R. Ona, Eduardo A. Robleto, Ronald E. Yasbin

Undergraduate Research Opportunities Program (UROP)

Here, we examine mutagenic programs that are independent of growth, such aspects of the evolutionary process are novel and have been implicated in the formation of cancers in animal cells and the acquisition of antibiotic resistance in animal pathogens. Adaptive or stationary phase mutagenesis is a genetic program to in increase diversity in cells under conditions of stress whereby cells escape non-dividing conditions. Previous research has shown that recombination functions are required to generate mutations that promote growth in Escherichia coli cells starved for carbon. This project tests the hypothesis that recombination functions are required for the generation of mutations …


Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Katherine Ona, Chris Ross, Ronald E. Yasbin, Eduardo A. Robleto Aug 2009

Dna Secondary Structures And Their Contribution To Mutagenesis In B. Subtilis Stationary Phase Cells, Carmen Vallin, Katherine Ona, Chris Ross, Ronald E. Yasbin, Eduardo A. Robleto

Undergraduate Research Opportunities Program (UROP)

It is widely known and accepted that the cause of many mutations in cells are generated during the replication process of actively dividing cells, however more recent research has shown that mutations also arise in non growing conditions, a phenomenon known stationary phase mutagenesis. Much of what is known come from studies in eukaryotic and bacterial models. It is proposed that in nongrowing cells, the process of transcription plays an important role in mutagenesis. I will test the hypothesis that secondary structures formed of DNA generated transcription promote mutagenesis. The sequences transcriptiongenerated structures are speculated to be prone to mutations …


Exploring Diversity Of Nitrate Reducing Thermophiles In Nevada Hot Springs, Jenny Lam, Jeremy A. Dodsworth, Brian P. Hedlund Aug 2009

Exploring Diversity Of Nitrate Reducing Thermophiles In Nevada Hot Springs, Jenny Lam, Jeremy A. Dodsworth, Brian P. Hedlund

Undergraduate Research Opportunities Program (UROP)

High rates of denitrification have been measured in Nevada geothermal hot springs, but little is known about the thermophiles that contribute to this activity. We hypothesize that heterotrophic bacteria in the genus Thermus are the most important denitrifiers in the springs. Alternatively, other microorganisms including chemolithotrophs may also be important. To test these hypotheses, several different strategies will be used to try to enrich and isolate nitrate-reducing microorganisms. Isolates will be identified by 16S rRNA gene PCR and sequencing. Subsequently, representative isolates will be chosen for nitrate reductase gene (narG) sequencing and for studies on the kinetics of nitrate reduction …


When Did The Ancestors Of Polynesia Begin To Migrate To Polynesia? The Mtdna Evidence, David Lesniewski Jan 2009

When Did The Ancestors Of Polynesia Begin To Migrate To Polynesia? The Mtdna Evidence, David Lesniewski

UNLV Theses, Dissertations, Professional Papers, and Capstones

The timing and nature of the migration of the ancestors of the Polynesian people is debated by two competing theories. The "Express Train" and "Slow Boat" theories assert that the migration of the Proto-Polynesian people began around 6,000 years before present (BP) or around 10,000 years BP respectively. Through the use of haplogroups and specific genetic mutations a direct relationship between the Proto-Polynesians and modern Polynesians was attempted to test which of these theories was correct. The ancient skeletal remains from the island of Borneo currently housed at UNLV were used in this study as their dates fall within both …