Structural characterization of metal binding in metallo-b-lactamases using x-ray absorption spectroscopy

In an effort to probe the structure and mechanism of metallo-b-lactamases, the metal-binding behaviors of several enzymes were studied using EXAFS (Extended X-ray Absorption Fine Structure). Three members of the metallo-b-lactamase subclass B1, BcII from Bacillus cereus, Bla2 from Bacillus anthracis and CcrA from Bacillus fragilis, were compared to examine metal-binding behavior within a subclass. Each system exhibits different metal-binding behavior including cooperative binding (BcII), sequential binding (CcrA), and differential binding between zinc(II) and cobalt(II) forms (Bla2). The metal-binding behavior of subclass B3 of L1 from Stenotrophomonas maltophilia was explored with RFQ (rapid-freeze quenched) EXAFS and site selective metal substitution. RFQ EXAFS show the metal coordination at 10 ms in the reaction in the native enzyme including a zinc-zinc distance (3.72\xc5) greater than is present in either the resting or product-bound states. Metal substitution incorporates cobalt(II) into the Zn2(DHH) of the enzyme and showed the metal-binding at each metal site

Play Dough and Plato: Finding Harmony in the Childhood Experience

Nineteenth-century philosopher Leo Tolstoy believed that art was an infectious way of communicating an idea or feeling from the artist to the viewer. Maxine Greene, a modern educational theorist, takes this idea a step further and suggests that the communicative power of art can have moral overtones, and she sees stories and the arts as necessary components of education that stir the imagination and impact moral development. Philosophers Plato and Jean-jacques Rousseau both found narrative powerful in forming identity and moral sense. Art, narrative, and philosophy are clearly entwined and related to the way we see and act in the world. My project seeks to make art and literature a catalyst in our understanding of our lives and of the human experience. I wrote and illustrated a children\u27s book about our experience of beauty in the world, as framed by Diotima in Plato\u27s Symposium and supported by other thinkers including Martha Nussbaum, Leo Tolstoy, and John Berger. This children\u27s book applies ideas presented in the thesis paper, which explores the role of stories particularly those that lead to philosophical discussions about values in childhood development, particularly moral development. The paper examines a variety of perspectives on the subject, ranging from ancient and modern philosophy to 20th- and 21st- century educational theories to contemporary developmental psychology

Spain in European reconstitutions of 1814-1815

Thesis (M.A.)--University of Kansas, History, 1932

Hands-On Training Emphasized in the Oregon Master Beekeeper Program

Honey bee colony declines have garnered immense public interest, and consequently there is a significant demand for the dissemination of apicultural information. The Oregon Master Beekeeper Program was developed in response to this increased interest in bees and beekeeping and a demand for a credible educational program for new beekeepers. The program focuses on hands-on training by matching students with volunteer mentors. Upon completion of the beginning (Apprentice) level, trained students may enroll in the advanced (Journey) level. This program has gained popularity and strives to educate beekeepers to promote sustainable beekeeping in the Pacific Northwest

Evaluation of the Effectiveness of the Oregon Master Beekeeper Program

The Oregon Master Beekeeper Program has been educating beekeepers since 2012. We surveyed program participants to evaluate the effectiveness of the training on beekeeping knowledge, confidence, and community involvement. The survey results showed positive changes in beekeepers, especially due to hands-on training by volunteer mentors, an integral component of the program. We also found areas for program improvement, such as providing more local contact with volunteers and addressing mentor-mentee scheduling issues. The insights gleaned from our survey could be used by those involved with other master beekeeper programs or similar Extension programs to strengthen educational offerings

Motion of the Zinc Ions in Catalysis by a Dizinc Metallo-β-Lactamase

We report rapid-freeze-quench X-ray absorption spectroscopy of a dizinc metallo-β-lactamase (MβL) reaction intermediate. The Zn(II) ions in the dinuclear active site of the S. maltophilia Class B3 MβL move away from each other, by ∼0.3 Å after 10 ms of reaction with nitrocefin, from 3.4 to 3.7 Å. Together with our previous characterization of the resting enzyme and its nitrocefin product complex, where the Zn(II) ion separation relaxes to 3.6 Å, these data indicate a scissoring motion of the active site that accompanies the ring-opening step. The average Zn(II) coordination number of 4.5 in the resting enzyme appears to be maintained throughout the reaction with nitrocefin. This is the first direct structural information available on early stage dizinc metallo-β-lactamase catalysis

The Economic Implications of Maine’s Changing Age Structure

The authors analyze the major implications of Maine’s aging population on the state’s workforce and economy. They note that there are steps that can be taken to partially mitigate the negative impacts and capitalize on the opportuni­ties associated with an aging population