768 research outputs found

    Biology and potential biogeochemical impacts of novel predatory flavobacteria

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    Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010Predatory bacteria are ubiquitous in aquatic environments and may be important players in the ecology and biogeochemistry of microbial communities. Three novel strains belonging to two genera of marine flavobacteria, Olleya and Tenacibaculum, were cultured from coastal sediments and found to be predatory on other bacteria on surfaces. Two published species of the genus Tenacibaculum were also observed to grow by lysis of prey bacteria, raising the possibility that predation may be a widespread lifestyle amongst marine flavobacteria, which are diverse and abundant in a variety of marine environments. The marine flavobacterial clade is known to include species capable of photoheterotrophy, scavenging of polymeric organic substances, pathogenesis on animals, the degradation and lysis of phytoplankton blooms and, now, predation on bacterial communities. Strains from the two genera were found to exhibit divergent prey specificities and growth yields when growing predatorily. Olleya sp. predatory cells accumulated to an order of magnitude greater cell densities than Tenacibaculum sp. cells on equivalent prey cell densities. Experiments were conducted to constrain the potential of the novel isolates to affect prey communities under more environmentally relevant conditions. An investigation of the minimum number of predatory cells needed to generate clearings of prey cells found that the inoculation of individual predatory flavobacteria cells can ultimately result in dense lytic swarms. In some cases, the susceptibility of particular prey species to lysis by a flavobacterial predator was found to vary based on the growth state of the prey cells or the presence of their spent growth media. A novel methodology for the experimental study of biofilms was used to assess the impact of exposure to predatory marine flavobacteria on the release of macronutrients from prey biofilms. The Olleya sp. predator had a stimulative effect on macronutrient release while the Tenacibaculum sp. did not, further suggesting the two groups of predators are adapted to different ecological niches.Support by the National Science Foundation (NSF) Division of Molecular and Cellular Biosciences Grant (MCB- 0348425), the MIT Student Assistance Fund, the Woods Hole Oceanographic Institution (WHOI) Academic Programs Office, WHOI Coastal Ocean Institute (COI) and WHOI Ocean Venture Fund grant, COI and the WHOI Ocean Life Institute

    Farmland valuation for estate tax purposes (1993)

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    Inflated land values have increased the impact of the federal estate tax on heirs of family farm operations. In an effort to alleviate the added tax burden, Congress included a special provision for farmland valuation for federal estate tax purposes in the Tax Reform Act of 1976. This publication explains the current use provision and presents the changes made by the Economic Recovery Tax Act of 1981.Reviewed October 1, 1993

    Marital Trust : an estate planning tool (1993)

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    Everybody has the right to pass property from one generation to another. However, this right is subject to federal estate and gift taxes and to Missouri estate taxes. Estate planning has two purposes: To provide for orderly distribution of property. To reduce the effect of taxes on this distribution of property. This publication discusses an estate planning tool called the marital trust. A marital trust can reduce the impact of estate taxes and provide professional management for assets passed at death. This publication emphasizes the recent federal estate and gift tax changes caused by the Economic Recovery Tax Act of 1981.Reviewed October 1, 1993

    Farmland valuation for estate tax purposes

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    "Inflated land values have increased the impact of the federal estate tax on heirs of family farm operations. In an effort to alleviate the added tax burden, Congress included a special provision for farmland valuation for federal estate tax purposes in the Tax Reform Act of 1976. This Guide explains the current use provision and presents the changes made by the Economic Recovery Tax Act of 1981."--First page.Stephen F. Matthews, Ronald L. Plain, and John C. Banning (Department of Agricultural Economics College of Agriculture)Revised 11/82/10

    Gifts and gift taxation

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    "Estate planning provides for orderly distribution of your assets during your lifetime and at death. Estate planning also minimizes the impact that federal and state transfer taxes can have on your estate. This Guide has general information on lifetime gifts as one of the various tools available to the estate planner. See your attorney for legal advice."--Page 1.Stephen F. Matthews, Ronald L. Plain, and John C. Banning (Department of Agricultural Economics, College of Agriculture)New 11/82/10

    Should you incorporate your farm?

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    "Because of estate, gift, and income taxes, many Missouri farmers are interested in forms of business organization that help decrease taxes and increase the inheritance for their children and other heirs. Three basic forms of farm business organizations are sole proprietorship, partnership, and corporation."--Page 1.Stephen F. Matthews, Ronald L. Plain and John C. Banning (Department of Agricultural Economics, College of Agriculture)Revised 1/83/12

    Biology and potential biogeochemical impacts of novel predatory flavobacteria

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    Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 147-160).Predatory bacteria are ubiquitous in aquatic environments and may be important players in the ecology and biogeochemistry of microbial communities. Three novel strains belonging to two genera of marine flavobacteria, Olleya and Tenacibaculum, were cultured from coastal sediments and found to be predatory on other bacteria on surfaces. Two published species of the genus Tenacibaculum were also observed to grow by lysis of prey bacteria, raising the possibility that predation may be a widespread lifestyle amongst marine flavobacteria, which are diverse and abundant in a variety of marine environments. The marine flavobacterial clade is known to include species capable of photoheterotrophy, scavenging of polymeric organic substances, pathogenesis on animals, the degradation and lysis of phytoplankton blooms and, now, predation on bacterial communities. Strains from the two genera were found to exhibit divergent prey specificities and growth yields when growing predatorily. Olleya sp. predatory cells accumulated to an order of magnitude greater cell densities than Tenacibaculum sp. cells on equivalent prey cell densities. Experiments were conducted to constrain the potential of the novel isolates to affect prey communities under more environmentally relevant conditions. An investigation of the minimum number of predatory cells needed to generate clearings of prey cells found that the inoculation of individual predatory flavobacteria cells can ultimately result in dense lytic swarms. In some cases, the susceptibility of particular prey species to lysis by a flavobacterial predator was found to vary based on the growth state of the prey cells or the presence of their spent growth media. A novel methodology for the experimental study of biofilms was used to assess the impact of exposure to predatory marine flavobacteria on the release of macronutrients from prey biofilms. The Olleya sp. predator had a stimulative effect on macronutrient release while the Tenacibaculum sp. did not, further suggesting the two groups of predators are adapted to different ecological niches.by Erin C. Banning.Ph.D

    Mens & Economie, Structuur en conjunctuur

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