Characterization of Glycation Sites on Human Serum Albumin using Mass Spectrometry

The modification of proteins by reducing sugars is a process that occurs naturally in the body. This process, which is known as glycation, has been linked to many of the chronic complications encountered during diabetes. Glycation has also been linked to changes in the binding of human serum albumin (HSA) to several drugs and small solutes in the body. While these effects are known, there is little information that explains why these changes in binding occur. The goal of this project was to obtain qualitative and quantitative information about glycation that occurs on HSA. The first section of this dissertation examined methods that could be used to quantify and identify glycation that occurs on HSA. The extent of glycation that occurred on HSA was quantified using oxygen-18 labeling mass spectrometry and the glycation sites were identified by observing the mass-to-charge (m/z) shifts that occurred in glycated HSA. This initial investigation revealed that oxygen-18 labeling based quantitation can be improved over previous methods if a relative comparison is done with oxygen-18 labeled peptides in a control HSA sample. Similarly, the process of making m/z shift-based assignments could be improved if only the peptides that were unique to the glycated HSA samples were used with internal calibration. These techniques were used in subsequent chapters for the assignment of early and late-stage glycation products on HSA. The regions of HSA that contained the highest amount of modification were identified, quantified, and ranked in order of their relative abundance. Of the commonly reported glycation sites, the N-terminus was found to have the highest extent of modification, followed by lysines 525, 199, and 439. The relative amount of modification on lysine 281, with respect to the aforementioned residues, varied with different degrees of glycation. The oxygen-18 labeling approach used for this analysis was novel because it allowed for the simultaneous quantification of all glycation-related modifications that were occurring on HSA. As such, several arginine residues were also found to have high amounts of modification on glycated HSA.

Reducing the Public Health Impact of Bovine Tuberculosis by Controlling Disease Transmission Between Cattle and White-Tailed Deer in Northwestern Minnesota

Bovine tuberculosis, caused by infection with Mycobacterium bovis, is a re-emerging zoonotic disease. It has staged a comeback by establishing infections in wildlife and cattle, creating the potential for human disease in locations where it was thought to be under control. In northwestern Minnesota, infected cattle and white-tailed deer were first discovered in 2005. A major bovine tuberculosis eradication campaign is underway in the state, with multiple efforts employed to control M. bovis infection in both cattle and deer populations. In order to effectively eradicate bovine tuberculosis in Minnesota, there is a need for better understanding of the factors that increase the risk of deer and cattle interacting in a way that facilitates tuberculosis transmission. By reducing the risk of disease transmission within the animal populations, we will also reduce the risk that bovine tuberculosis will again become a common disease in human populations. The purpose of this study is to characterize the risk of interactions between cattle and white-tailed deer in northern Minnesota in order to prevent M. bovis transmission. A survey originally developed to assess deer-cattle interactions in Michigan was modified for use in Minnesota, introducing a scoring method to evaluate the areas of highest priority at risk of potential deer-cattle interaction. The resulting semi-quantitative deer-cattle interaction risk assessment was used at 53 cattle herds located in the region adjacent to the bovine tuberculosis “Core Area”. Two evaluators each scored the farm separately, and then created a management plan for the farm that prioritized the areas of greatest risk for deer-cattle interactions. Herds located within the “Management Zone” were evaluated by Minnesota Board of Animal Health staff, and results from these surveys were used as a point of comparison.

Use of Confined Dogs for Reducing Deer Damage to Apple Orchards

We assessed the efficacy of free-ranging dogs, confined by buried fences and electronic collars, for reducing deer damage to apple trees in three commercial apple orchards in Oswego County, New York State. During 1995 and 1996, we monitored paired dog-protected and control plots in each orchard. Within dog-protected areas, the percentage of damaged buds was lower, and fruit yield was higher in both 1995 and 1996 than for control plots. Gross economic returns were higher from dog-protected than control plots in both 1995 (by 51%) and 1996 (by 184%). After two seasons of growth, trees planted in May 1995 had nearly three times the cross-sectional area, and were 60% taller if they were in dog-protected rather than control plots. Dogs provided increased economic returns for growers at much lower cost than conventional barrier fencing.

Thermal Imagery Applied to Reducing Bird Hazards to Aircraft at Airports

Airports worldwide are at a disadvantage when it comes to being able to spot birds and warn aircrews about the location of flocks either on the ground or close to the airfield. Birds simply cannot be easily seen during the day and are nearly invisible targets for planes at night or during low visibility. Thermal imaging (infrared) devices can be used to allow ground and tower personnel to pinpoint bird locations day or night, thus giving the airport operators the ability to launch countermeasures or simply warn the aircrews. This technology is available now, though it has been predominately isolated to medical and military system modifications. The cost of these devices has dropped significantly in recent years as technology, capability, and availability have continued to increase. Davison Army Airfield (DAAF), which is located about 20 miles south of Ronald Reagan National Airport in Washington, DC, is the transient home to many bird species including an abundance of ducks, seagulls, pigeons, and migrating Canadian geese. Over the past few years, DAAF implemented a variety of measures in an attempt to control the bird hazards on the airfield. Unfortunately, when it came to controlling these birds on or near our runways and aircraft movement areas we were more reactive than proactive. We would do airfield checks several times an hour to detect and deter any birds in these areas. The deterrents used included vehicle/human presence, pyrotechnics, and the periodic use of a trained border collie. At the time, we felt like we were doing all we could to reduce the threat to aircraft and human life. It was not until a near fatal accident in October 1998, when we truly realized how dangerous our operating environment really was to aircraft at or near the airfield. It was at this time, we had a C-12 (twin-engine passenger plane) land on our primary runway at night. The tower cleared the aircraft to land, and upon touchdown to the runway the aircraft collided with a flock of geese. Neither the tower nor the crew of the aircraft saw the geese because they were obscured in the darkness. The end result was 12 dead geese and $374,000 damage to the C-12. Fortunately, there were no human fatalities, but it was painfully clear we needed to improve our method of clearing the runway at night and during low visibility conditions. It was through this realization that we ventured to the U.S. Army Communications and Electronics Command for ideas on ways to deal with our threat. It was through a sub-organization within this command, Night Vision Labs, that we realized the possibilities of modifying thermal imagery and infrared technology to detecting wildlife on airports.

REDUCING NUISANCE CANADA GOOSE PROBLEMS THROUGH HABITAT MANIPULATION

Urban populations of Canada geese (Branta canadensis) cause considerable problems when large numbers congregate in parks, playing fields, and backyards. In most cases, geese are drawn to these sites to feed on the lawns. I tested whether geese have feeding preferences for different grass species. Captive Canada geese preferred Kentucky bluegrass (Poa pratensis) and disliked tall fescue (Festuca arundinaceae) over colonial bentgrass (Agrostis tenuis cv. Highland), perennial ryegrass (Lolium perenne), and red fescue (Festuca rubra). They refused to eat some other ground covers such as pachysandra (Pachysandra terminalis) and English ivy (Hedera helix). These results suggest that goose numbers at problem sites could be reduced by changing the ground cover. I also compared the characteristics of foraging sites used by geese to other foraging sites that geese avoided. Occupied sites were more open so that geese had clearer visibility and greater ease in taking off and landing. This suggests that goose numbers at problem sites also could be reduced by planting tall trees to make it harder for the geese to fly away, and planting bushes and hedges to obstruct a goose's visibility.

EFFECTS OF A BIRD HAZARD REDUCTION FORCE ON REDUCING BIRD/AIRCRAFT STRIKE HAZARDS AT THE ATLANTIC CITY INTERNATIONAL AIRPORT, NJ

Bird-aircraft strikes at the Atlantic City International Airport (ACY) increased from 18 in 1989 to 37 in 1990. The number of bird-aircraft strikes involving gulls (Larus spp.) during this time rose from 6 to 27, a 350% increase. The predominant species involved in bird strikes was the laughing gull (L. atricilla). Pursuant to an interagency agreement between the U.S. Department of Transportation (USDOT), Federal Aviation Administration (FAA) and the U.S. Department of Agriculture (USDA)l Animal and Plant Health Inspection Service (APHIS)/Animal Damage Control (ADC), ADC established a Emergency/Experimental Bird Hazard Reduction Force (BHFF) at ACY in 1991. An Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) for the 1991 Emergency/Experimental BHRF was executed and signed by the FAA on 19 May 1991. The BHRF was adopted at this time by the FAA Technical Center as an annual program to reduce bird strikes at ACY. The BHRF goals are to minimize or eliminate the incidence of bird-aircraft strikes and runway closures due to increased bird activities. A BHRF team consisting of ADC personnel patrolled ACY for 95 days from 26 May until 28 August 1992, for a total of 2,949 person-hours. The BHRF used a combination of pyrotechnics, amplified gull distress tapes and live ammunition to harass gulls away from the airport from dawn to dusk. Gullaircraft strikes were reduced during BHRF operations in 1992 by 86% compared to gull strikes during summer months of 1990 when there was not a BHRF team. Runway closures due to bird activity decreased 100% compared to 1990 and 1991 closures. The BHRF should continue at ACY as long as birds are a threat to human safety and aircraft operations.

Adopting an integrated, flexible approach to reducing the birdstrike risk from Canada geese

Canada Geese overflying the runways at London’s Heathrow Airport have been struck on eleven occasions by aircraft during the last ten years. Four of these occurred during the pre-breeding season and seven during the post moult period. A monitoring study was initiated in 1999 to evaluate the movements of geese around the airport and determine appropriate mitigation strategies to reduce the risk of birdstrike. Moult sites within 13km of the airport were identified. 4,900 moulting geese were caught and fitted with colour rings and radio-transmitters between 1999 and 2004. 2,500 visits were made to over 300 sites resulting in over 10,000 sightings of known individuals. Birds that crossed the airport approaches whilst moving between roost sites and feeding areas in newly harvested cereal crops were identified. Throughout the monitoring period efforts were made to control the risk, but by 2003 it was estimated that 10,000 bird transits of the approaches involving almost 700 individuals occurred during a 50 day period. The knowledge of the movements of ringed and tagged birds was used to inform a revised habitat management, daily roost dispersal and on-airfield bird deterrence programme in 2004. By adopting a flexible approach to management, an estimated 70% reduction in bird transits was achieved. This paper discusses the techniques used to achieve this reduction.