Investing in wildlife

Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/114841/1/39015062459345.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/114841/2/39015062459345.pd

A peptide derived from human bactericidal/ permeability-increasing protein (BPI) exerts bactericidal activity against Gram-negative bacterial isolates obtained from clinical cases of bovine mastitis

Gram-negative bacteria are responsible for approximately one-third of the clinical cases of bovine mastitis and can elicit a life-threatening, systemic inflammatory response. Lipopolysaccharide (LPS) is a membrane component of Gram-negative bacteria and is largely responsible for evoking the inflammatory response. Antibiotic and anti-inflammatory therapy for treating Gram-negative infections remains suboptimal. Bactericidal/permeability-increasing protein (BPI) is a neutrophil-derived protein with antimicrobial and LPS-neutralizing properties. Select peptide derivatives of BPI are reported to retain these properties. The objective of this study was to evaluate the antimicrobial activity of a human BPI-derived synthetic peptide against clinical bovine mastitis isolates of Gram-negative bacteria. A hybrid peptide was synthesized corresponding to two regions of human BPI (amino acids 90–99 and 148–161), the former of which has bactericidal activity and the latter of which has LPS-neutralizing activity. The minimum inhibitory (MIC) and bactericidal (MBC) concentrations of this peptide against various genera of bacteria were determined using a broth microdilution assay. The MIC’s were determined to be: 16–64 mg/ml against Escherichia coli; 32–128 mg/ml against Klebsiella pneumoniae and Enterobacter spp.; and 64–256 mg/ml against Pseudomonas aeruginosa. The MBC’s were equivalent to or 1-fold greater than corresponding MIC’s. The peptide had no growth inhibitory effect on Serratia marcescens. The antimicrobial activity of the peptide was retained in the presence of serum, but severely impaired in milk. Further functional evaluation of the peptide demonstrated its ability to completely neutralize LPS. Together, these data support additional investigations into the therapeutic application of BPI to the treatment of Gram-negative infections in cattle

An Ecosystem Approach to Recreation Location Quotients

Despite the widespread agreement on the importance of preserving ecological integrity in conservation and outdoor recreation decision-making processes, traditional metrics analyzing the supply of and demand for conservation and recreation resources have focused on geographical and population-centric units of measurement rather than ecological ones. One tool past researchers have used to inform recreation resource planning is the recreation location quotient (RLQ). While simple park-to-population ratios or acres-per-capita metrics provide a base measure of carrying capacity and are often useful to set broad recreation supply standards, the RLQ offers a more nuanced snapshot of supply and demand by comparing regional ratios to a standardized reference region. The RLQ is thus able to provide a statistic or quotient that highlights regions where recreation resources are particularly abundant and/or scarce relative to a reference area. This project expands the past RLQ analyses by investigating the distribution of recreation resources across the 10 ecological sections found within the US state of Minnesota. RLQs were calculated using recreation trail mileage, natural resource and recreation area acreage data, and recreation facility data from federal, state, and local agencies. Results found notable differences in supply of recreation resources across ecological sections. Some sections were considerably underrepresented in recreation resources-per area (e.g., Red River Valley and North Central Glaciated Plains) while others were underrepresented in recreation resources-per capita (e.g., Minnesota and Northeast Iowa Morainal). The RLQ statistics and resulting maps illustrating relative surplus or deficiencies can inform future land acquisition decisions and highlight the need for cross-jurisdictional planning in order to ensure outdoor recreation systems are ecologically representative. Possible implications and recommendations for future planning decisions are discussed

Single-Molecule Study of Ribosome Hierarchic Dynamics at the Peptidyl Transferase Center

During protein biosynthesis the ribosome moves along mRNA in steps of precisely three nucleotides. The mechanism for this ribosome motion remains elusive. Using a classification algorithm to sort single-molecule fluorescence resonance energy transfer data into subpopulations, we found that the ribosome dynamics detected at the peptidyl transferase center are highly inhomogeneous. The pretranslocation complex has at least four subpopulations that sample two hybrid states, whereas the posttranslocation complex is mainly static. We observed transitions among the ribosome subpopulations under various conditions, including 1), in the presence of EF-G; 2), spontaneously; 3), in different buffers, and 4), bound to antibiotics. Therefore, these subpopulations represent biologically active ribosomes. One key observation indicates that the Hy2 hybrid state only exists in a fluctuating ribosome subpopulation, which prompts us to propose that ribosome dynamics are hierarchically arranged. This proposal may have important implications for the regulation of cellular translation rates