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Bees and other pollinators play an essential role in maintaining the plant biodiversity of our planet's landscape through pollination. Few baseline studies or monitoring programs have addressed concerns over local, regional and even worldwide declines in bee populations. We established 22 collection sites in meadow and grassland habitats in Marin County, California to determine which bee genera were present and which plants they were visiting. Some of these habitats were located in National Park Service natural areas and wildlands, including Golden Gate National Recreation Area and Point Reyes National Seashore. During this study we collected a total of 109 bee, wasp and fly specimens and from among these we identified seven genera of bees. The bees were found on 44 species of plants, only 11 of which were native to Marin County. The European honey bee (Apis mellifera), a non-native pollinator, was found on 37 species of plants, 28 of which were non-native.
The two-toed amphiuma, Amphiuma means, is a large aquatic salamander and a potentially important predator of crayfish. However, little is known about the effects of predation by A. means on crayfish communities. This study was carried out to determine if there is a size preference in A. means predation on crayfish. A. means was expected to prefer medium sized crayfish in accordance with the optimal foraging theory because they were more energetically rewarding than smaller crayfish but easier to capture than larger crayfish. Seven similarly-sized A. means were placed in individual aquatic mesocosms. Six crayfish of the subgenus Scapulicambarus, two from each of three size categories, were also placed in each tub. The percent mortality and location of the crayfish in the tub were observed for 11 days. A. means had a significant preference for medium-sized crayfish on day four, but there were no significant differences among predation rates by the final day. Small crayfish had the lowest predation rates. Surviving crayfish were found most often on the edges of the tubs. Medium-sized crayfish may have experienced the highest amount of predation because they have weaker defenses than large crayfish and are unable to hide as well as small crayfish. However, crayfish may be unable to outgrow predation because even some of the largest crayfish were preyed upon during the experiment.
In previous studies, experimenters have found that the risk of atopic disease is increased due to less exposure to infection and increased antibiotic use during immune system development. The data have supported this finding in accordance with hay fever, eczema and atopy, but are inconclusive regarding asthma. This study aims to further research the effects of antibiotic use and immune system challenge early in life on the development of allergic asthma. This was done retrospectively by collecting data from labor and delivery records of mothers who delivered vaginally, pediatric records up until age two, and participant completed questionnaires concerning family medical history and home environment information. A total of 206 women and 277 children, of which 18.4% have asthma, were enrolled in the study. Children who were prescribed antibiotics anytime after birth until two years of age were statistically more often diagnosed with asthma than those who were not given antibiotics (OR 2.884, CI 1.093-7.637). Results also suggest that babies who were born pre-term (<37 weeks gestation) were statistically more likely to be asthmatic which may reflect insufficient lung development (OR 3.048, CI 1.191-7.801). Birth order and exposure to antibiotics administered to the mother during delivery, which can correspond to immune system challenge, were determined to have no statistical relationship with asthma diagnoses. This research supports that allergic asthma is dissimilar to other atopic diseases in relation to birth order. More data are currently being collected to further study these relationships.
Consideration for the use of microalgae as a feedstock for commercial biofuels production began in the 1970s. While high production costs and inefficiencies impeded private industry scale up to meet national energy needs, recent energy supply concerns and market instability has revitalized this alternative energy process. A key factor in using microalgae comes from efficiently harvesting algae oils which are chemically similar to fossil fuel oils. Technological advances have been made to genetically engineer microalgae to accumulate oils but these procedures are time consuming and expensive. Others have made progress in using natural processes in the environment to cause algae to produce oils. Considerable research has shown determining the appropriate mix of light, temperature and CO2 can foster oil accumulation in select microalgae strains. Using an experimental design, the freshwater algae, Chlorella pyrenoidosa and Ettlia sp. were subjected to various environmental conditions to investigate effects on oil production. When exposed to a higher irradiance level (400 μE), C. pyrenoidosa achieved a significantly higher cell count leading to an increase in lipid productivity. Under media manipulation effects, the cell count for nitrogen-limited cultures was significantly lower than that of cultures grown on replete medium. Nitrogen limitation seems to negatively impact lipid productivity under our experimental conditions. Supplementation with 2 % CO2, led to an increase in growth after seven days of incubation; however, growth decreased subsequently to a slower rate as compared to growth with air sparging after 12 days of incubation. There appeared to be a degree of variability with regards to lipid ratios, with increases in neutral lipids in cultures exposed to higher levels of irradiance, nitrogen limitation and additional CO2. Although analysis showed that environmental manipulation is feasible in terms of oil accumulation for these select strains, further study is warranted in investigating other oil-accumulating microalgae strains for commercial production.
Staphylococcus aureus and Candida albicans form dense biofilms together on internal medical devices and in doing so, establish a source of infection that is difficult to treat and can cause extensive local and systemic disease. The goal of the present study was to gain further insight into whether interactions between these two species within a biofilm alter their attachment to artificial surfaces and growth rates. After first establishing that S. aureus and C. albicans interact with one another and grow well together in the described biofilm system, the two species were mixed and attachment was assessed. S. aureus had differing effects on yeast attachment depending on when the two were mixed whereas C. albicans had no noticeable affect on S. aureus attachment. Examination of mixed biofilm structural integrity revealed that pure C. albicans biofilms have higher levels of detachment after 16 h of growth and a lower resistance to shear stress than do mixed biofilms. Similarly, measurement of biofilm growth rates indicated that chemical and metabolic interactions between the two species result in changes to their growth rates within biofilms. Collectively, the findings presented here suggest that S. aureus and C. albicans have a complex relationship that involves a variety of physical and chemical interactions. As a result, we believe new treatment strategies should focus on disrupting the community as a whole and all of its interactions rather than targeting individual members of the biofilm.
The following chapters have sent in officer slates for 2012-2013. Officers are listed in the order of President, Vice President, Secretary, Treasurer, Historian, and Faculty Advisor unless otherwise noted. The chapters are listed alphabetically by Greek name. Please submit new slates, changes and corrections to Lori.Kelman@montgomerycollege.edu.