Cell-to-cell communication by chemical signals, termed quorum sensing (QS), is a common regulatory scheme in the microbial world. Pseudomonas aeruginosa¸ an opportunistic pathogen of burn wounds and cystic fibrosis lungs, uses QS to control the expression of hundreds of genes, particularly those necessary for population level benefits such as biofilm...
Cooperative behaviors in bacteria are increasingly appreciated for their relevance to microbial ecology and utility as model systems for social evolution. One example is the secretion of siderophores, a structurally diverse group of compounds that chelate extracellular iron. Siderophore production is considered cooperative because the benefits can be shared with...
Nitrification is the process within the global Nitrogen Cycle where ammonia (NH3) is oxidized to nitrate (NO₃⁻) and can be carried out by two distinct groups of bacteria. The ammonia-oxidizing bacteria (AOB) first oxidize NH₃ to nitrite (NO₂⁻), and second, the nitrite-oxidizing bacteria (NOB) oxidize NO₂⁻ to NO₃⁻. In aerobic...
Nitrification is a critical step in the global nitrogen cycle involving the biological oxidation of ammonia (NH₃) to nitrite (NO₂⁻ ) and then to nitrate (NO₃⁻). The first step in nitrification is carried out by NH₃-oxidizing bacteria (AOB) and archaea (AOA), and the second by NO₂⁻-oxidizing bacteria (NOB). In addition...
The agriculture production system in the post-war United States is characterized
as highly specialized and increasingly dependent on off-farm inputs. Although the US
has traditionally supported agriculture with numerous government commodity programs
such as target prices, nonrecourse loans, and deficiency payments, agriculture today is
perceived as one of the major...
The concept of ecosystem management requires that management prescriptions account for economic and environmental goals that are measured in non-commensurate units. This study examines the economic and environmental trade-offs associated with planting a riparian buffer in trees to reduce stream temperatures in the Mohawk watershed, Oregon. The detrimental effects of...
Wheat (Triticum aestivum) is a highly valuable crop that makes up a large portion of the world’s food. However, breeding for improved varieties with desirable characteristics can be a challenge. This research examined two different issues wheat breeders deal with throughout the selection process all the way to production of...
Mutation of repetitive DNA by repeat-induced point mutation (RIP) is a process that occurs in many filamentous fungi of the Ascomycota during the sexual cycle. Concurrently, direct DNA repeats are often deleted by homologous recombination at high frequency during the sexual cycle. Thus, the processes of RIP and deletion compete...
Fungi are capable of growth on a wide variety of carbon sources, both living and dead. They can produce an arsenal of enzymes and transporters for harvesting sugars, polysaccharides, amino acids, lipids and micronutrients from their environments [1]. Within the nucleus of a cell, transcription factors (TF) control whether genes...
Pseudomonas aeruginosa is an opportunistic human pathogen that infects immunocompromised individuals such as those suffering from burns or the genetic disorder cystic fibrosis. This organism utilizes a cell-cell communication mechanism known as quorum sensing (QS) to coordinate virulence gene expression and biofilm formation. It has three interconnected QS systems, namely...