Gene Transfer and Cloning of the Amino-Acid Transport System L from Human Cells

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72389/1/j.1749-6632.1985.tb14893.x.pd

Bennett Arboretum: Past, Present, and Future of Michigan's Oldest Public Arboretum

Abstract Established in 1934, Bennett Arboretum is the state of Michigan’s oldest public arboretum. The Arboretum is located in western Wayne County and is managed by the Wayne County Department of Parks. The arboretum has experienced a decline in management activities since the middle of the 20th century and is hardly recognizable today. My goal for this project was to improve the image of the Arboretum in the context of this historical area of Metropolitan Detroit. In order to understand the intentions of the Bennett Arboretum’s founder J.M. Bennett, I conducted a historical review of Wayne County Michigan’s early evolution and I focus on the early 20th century. This time period is significant because of the development of the automobile industry in the area and the direct influence that this industry had on the development of the park system. I then conducted a historical review of arboreta throughout the world tracing the origins of this style of planting to the Arboretum Trsteno, in Croatia. I then followed the development of arboreta as it moved to a symbol of national pride. I then looked at two highly successful arboreta in the United States: The Arnold Arboretum and the University of Wisconsin - Madison - Arboretum. These two arboreta represent distinctly different arboreta that have evolved over time. In the summer of 2004 I surveyed Bennett Arboretum to determine what proportion of trees have survived since its establishment and evaluated each tree’s condition. Of the nearly 470 trees originally planted, 103 trees remained from the original collection. The results of the survey formed the basis for a Master Plan for the Arboretum in 2005, created by myself and my peers in a Landscape Architecture Studio at the University of Michigan. The development of the Master plan created a mission statement which shifted the focus of the Arboretum to an ecosystem based approach for plant collection. I selected two significant areas of the Master Plan that required merging the historic collection with this new ecosystem approach. I created a planting plan for the Ornamental and Maple Collections. These two plans create a framework that blends the different collection styles to create a seamless flow throughout and help strengthen Bennett Arboretum’s visual image.Master of Landscape ArchitectureNatural Resources and EnvironmentUniversity of Michigan, School of Natural Resources and Environmenthttp://deepblue.lib.umich.edu/bitstream/2027.42/35330/2/BenOxenderPracticum4-18-2006.pd

BINDING PROTEINS AND MEMBRANE TRANSPORT fn1

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72841/1/j.1749-6632.1975.tb31496.x.pd

Reconstitution of neutral amino acid transport from partially purified membrane components from ehrlich ascites tumor cells

Solubilized protein fractions have been obtained from plasma membranes of Ehrlich ascites cells either by extraction with 0.5% Triton X-100 or by extraction with 2% cholate. Partial purification of the solubilized protein fraction has been obtained by utilizing a combination of ammonium sulfate precipitation and column chromatography. Leucine-binding activity has been detected in the Triton X-100 solubilized membrane fraction. The leucine-binding activity was measured by equilibrium dialysis and was saturable with high levels of leucine or phenylalanine and is not strongly effected by alanine. These properties are similar to those previously identified as System L. In addition, the cholate extracted protein fraction was partially purified and reconstituted into liposomes. Sodium dependent uptake of alanine and leucine could be demonstrated in the reconstituted vesicles. Concentrative uptake was dependent upon a sodium gradient. A membrane potential produced by valinomycin mediated potassium diffusion in the presence of sodium also stimulated amino acid transport in reconstituted liposomes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38206/1/400070317_ftp.pd

What are the requisites for a model transport analog?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27404/1/0000437.pd

On the nature of the "non-saturable" migration of amino acids into Ehrlich cells and into rat jejunum

The so-called non-saturable uptake of [alpha]-amino acids by the Ehrlich cell, even though it occurs at a characteristically slow rate for various neutral amino acids (whether they are in the - or the -form) is nevertheless structurally specific, since the uptake of [beta]-alanine, taurine and betaine occurs only about one-third as rapidly as that of the [alpha]-amino acids. Furthermore the uptake shows a considerable sensitivity to pH, and a temperature sensitivity so high as to exclude simple diffusion as the rate-limiting step. The structural specificity is compatible with a reaction of the amino acid with a membrane site, either an abundant one or a relatively unreactive one, the reaction of the amino acid with which presumably need involve at most only its amino and carboxyl groups.Uptake of amino acids at high levels by rat-intestinal segments also showed high temperature sensitivities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33468/1/0000872.pd

Secretion of mutant leucine-specific binding proteins with internal deletions in Escherichia coli

The leucine-specific binding protein, encoded by the livK gene, is located in the periplasm of E. coli . The present study is an attempt to identify intragenic regions that determine the efficiency of its secretion into the periplasm. C-terminal deletions or fusions of the livK gene to trpA (encoding the Α subunit of tryptophan synthetase) were secreted with little loss of efficiency [1]. A series of deletions was constructed at the unique Sphl site within livK , near the 5' end of the region coding for the mature protein. Between 16 and 113 amino acids were deleted in the amino-terminal one-third of the protein. A few of these deletions were located within a few amino acids of the signal sequence processing site. Deletions extending within thirteen residues of the processing site were processed and secreted more slowly than normal. Secondary structure predictions suggested that the Α-helical core region of the signal sequence extends into the mature protein in the case of the slow processing mutants, perhaps interfering with the recognition site for leader peptidase or other secretory components. These results suggest that the conformation around the signal processing site may be a critical factor in determining the efficiency of secretion. During the course of this study, it was found that the difference in molecular weight between precursor and mature forms of some binding protein mutants, as judged by SDS-PAGE, was much greater than could be accounted for by processing of the signal sequence. This anomalous mobility on gels, however, could be eliminated by performing SDS-PAGE in the presence of 6 M urea.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38450/1/240460407_ftp.pd

The regulation of neutral amino acid transport by amino acid availability in animal cells

Animal cells regulate the activities of neutral amino acid transport Systems A and L to keep the intracellular supply of amino acids relatively constant. Transport System A activity increases dramatically in response to starvation of all the amino acids. Transport System L activity increases in response to starvation of a single substrate such as leucine. The mechanism of regulation appears to be different for Systems A and L.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25123/1/0000556.pd

Recent advances in prokaryotic peptide transport

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25590/1/0000134.pd

Barriers to US industrial biotechnology research consortia

In 1986-1987, the research directors of major and medium-sized US biotechnology companies agreed on the wisdom of developing cooperative research arrangements in protein engineering, bioprocess and large-scale animal cell culture technologies. However, upper-level corporate managers were not convinced that collaborative approaches would be essential for the maintenance of longterm competitiveness of the US biotechnology industry. Now that cooperative research efforts in Japan and Europe are beginning to challenge US supremacy in biotechnology, the prospect of US industry consortia may be viewed in a kinder light. We believe that the US government has a key role to play in providing both financial and logistical support.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27775/1/0000169.pd