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Movable genetic elements: detection of changes in maize DNA at the Shrunken locus due to the intervention of Ds elements

Description: This report describes our initial attempts at the molecular characterization of a maize controlling element. We have prepared a cDNA probe and used it to detect changes at a locus where Ds elements are found. Evidence of their presence are indicated by changes in the restriction patterns, but there is as yet no information on the physical nature of the controlling elements nor on the kinds of rearrangements they cause.
Date: May 28, 1980
Creator: Burr, B. & Burr, F.A.
Partner: UNT Libraries Government Documents Department

Status of solid-phase enzyme immunoassays

Description: Solid-phase enzyme immunoassays are becoming increasingly popular due to their sensitivity, simplicity, and versatility. The three most common types of these assays (indirect, double-antibody, and competitive binding) have been described and examples given of their use. Short discussions of various aspects of the ''art'' of performing solid-phase EIAs have been included. Finally, a brief overview of the Technicon automated EIA processor has been presented.
Date: January 1, 1978
Creator: Saunders, G.C.
Partner: UNT Libraries Government Documents Department

Sources of data in the GenBank database

Description: The citations in GenBank are characterized with respect to form of publication. The potential spectrum of quality control problems applicable to the various types of unpublished data are discussed. 6 refs., 2 tabs.
Date: January 1, 1987
Creator: Burks, C.
Partner: UNT Libraries Government Documents Department

A probe-based mapping strategy for DNA sequencing with mobile primers

Description: Research on DNA sequencing continued. The specific areas of research targeted for the period of this Progress Report included three general phases: (1) optimization of probe-mapping by both the development of new transposons and the design of stream-lined methods for mapping; (2) application of transposon-based methods to larger plasmids and cosmids; and (3) initiation of PCR-based applications of transposons.
Date: January 1, 1991
Creator: Strausbaugh, L.D. & Berg, C.M.
Partner: UNT Libraries Government Documents Department

Flow cytogenetics: Fundamentals and new developments

Description: The purpose of this report is to provide (1) an introduction to flow cytogenetics and (2) resource information for additional and more detailed information for those interested in either using or further developing the technology. Several recent reviews are available and provide in-depth information on all aspects of flow cytogenetics, this information will by and large, not be repeated here. Examples of common types of flow cytogenetic data are included along with an explanation of their interpretation. In addition, recent developments are discussed as examples of what one can anticipate for the future. Further developmental needs are discussed in hopes of stimulating new ideas.
Date: January 1, 1992
Creator: Cram, L.S.; Fawcett, J. & Deaven, L.L.
Partner: UNT Libraries Government Documents Department

Nonlinear electrodynamics in cytoskeletal protein lattices

Description: Cytoskeletal lattice proteins including microtubules are particularly involved in dynamic regulation of intracellular movements and activities. This paper considers possibilities and implications of biological information processing due to coupling of Davydov solitons, Frohlich coherent oscillations and other nonlinear electrodynamic phenomena to conformational states of the grid-like polymer subunits of cytoskeletal microtubules. 39 references.
Date: January 1, 1983
Creator: Hameroff, S.R.; Smith, S.A. & Watt, R.C.
Partner: UNT Libraries Government Documents Department

The human telomere

Description: An ultimate goal of human genetics is the generation of a complete physical and ''functional'' map of the human genome. Twenty-five percent of human DNA, however, consists of repetitive DNA sequences. These repetitive DNA sequences are thought to arise by many mechanisms, from direct sequence amplification by the unequal recombination of homologous DNA regions to the reverse flow of genetic information. A general outline of the chromosomal organization of these repetitive sequences will be discussed. Our working hypothesis is that certain classes of human repetitive DNA sequences ''encode'' the information necessary for defining long-range genomic structure. Evidence will be presented that the first goal of this research, the identification and cloning of the human telomere, has been achieved. A human repetitive DNA library was constructed from randomly sheared, reassociated, and oligo(G/center dot/C)-tailed DNA, a method that minimizes the potential loss of sequences devoid of a given restriction enzyme site. Sequences too large to clone efficiently in cosmid or /lambda/ vectors, such as centromeric repeats, or telomeric sequences with an end incompatible for cloning, should be present in this library. In order to isolate highly conserved repetitive DNA sequences, this library was screened with radiolabeled hamster Cot50 repetitive DNA. Two clones, containing tandem arrays of the sequence (TTAGGG), were isolated by this method. 30 refs., 1 fig., 2 tabs.
Date: January 1, 1989
Creator: Moyzis, R.K.
Partner: UNT Libraries Government Documents Department

The National Laboratory Gene Library Project

Description: The two National Laboratories at Livermore and Los Alamos have played a prominent role in the development and application of flow cytometry and sorting to chromosome classification and purification. Both laboratories began to receive numerous requests for specific human chromosomal types purified by flow sorting for gene library construction, but these requests were difficult to satisfy due to time and personnel constraints. The Department of Energy, through its Office of Health and Environmental Research, has a long-standing interest in the human genome in general and in the mutagenic and carcinogenic effects of energy-related environmental pollutants in particular. Hence, it was decided in 1983 to use the flow construct chromosome-specific gene libraries to be made available to the genetic research community. The National Laboratory Gene Library Project was envisioned as a practical way to deal with requests for sorted chromosomes, and also as a way to promote increased understanding of the human genome and the effects of mutagens and carcinogens on it. The strategy for the project was developed with the help of an advisory committee as well as suggestions and advice from many other geneticists. 4 refs., 2 tabs.
Date: January 1, 1988
Creator: Deaven, L.L. & Van Dilla, M.A.
Partner: UNT Libraries Government Documents Department

Bimolecular dynamics by computer analysis

Description: As numerical tools (computers and display equipment) become more powerful and the atomic structures of important biological molecules become known, the importance of detailed computation of nonequilibrium biomolecular dynamics increases. In this manuscript we report results from a well developed study of the hydrogen bonded polypeptide crystal acetanilide, a model protein. Directions for future research are suggested. 9 references, 6 figures.
Date: January 1, 1984
Creator: Eilbeck, J.C.; Lomdahl, P.S. & Scott, A.C.
Partner: UNT Libraries Government Documents Department

(Multiplex mapping of human cDNAs)

Description: J. Craig Venter, National Institute of Neurological Disorders and Stroke, has begun to identify genes expressed in the human brain by partially sequences cDNA clones. We are collaborating with the Venter group and using their sequence data to develop methods for rapid localization of newly identified cDNAs to human chromosomes. We are applying the ABI automated DNA sequencer to the analysis of fluorescently-tagged PCR products for assigning sequences to individual human chromosomes. The steps in our mapping protocol are (1) to design PCR primers from the Venter laboratory-generated sequence data, (2) to test the primers for specific amplification from human genomic DNA, (3) to use the primers for PCR amplification from a somatic cell hybrid cell mapping panel, (4) to determine the presence or absence of the specific amplification products from each cell line DNA by electrophoretic analysis using the ABI sequencer, and (5) to analyze the pattern of amplification results from the hybrid panel to identify the chromosomal origin of the cDNA sequence. We have demonstrated the principle by mapping 12 sequences or Expressed Sequence Tags'' (ESTs), providing primer sequence data for subsequent subchromosomal localizations. We will now concentrate on developing methodology to allow multiplexing the amplification reactions and analysis of the reaction products, to achieve a high throughput with a minimum allocation of resources. This project will generate a data set from which to evaluate strategies to identify functional primer sequences from cDNA sequence data.
Date: January 1, 1991
Creator: Nierman, W.C.
Partner: UNT Libraries Government Documents Department

Characterization of a 1,4-. beta. -D-glucan synthase from Dictyostelium discoideum

Description: Various aspects of research concerning Dictyostelium discoideum are presented. The initial focus of this project was upon: the characterization of potential probes for the cellulose synthase (antibody and nucleic acid), the determination of the cultural induction conditions of cellulose synthesis, the solubilization of the enzyme activity, the development of a non-inhibitory disruption buffer, the generation and isolation of mutant strains deficient in cellulose synthesis, and the development of the capability to determine the degree of polymerization of the in vitro product. I have briefly summarized our most significant findings with only selected data sets being shown in this report in the interest of brevity.
Date: January 15, 1992
Creator: Blanton, R.L.
Partner: UNT Libraries Government Documents Department

(Calcium gating of proton fluxes in chloroplasts)

Description: Work supported by this grant has been aimed at better understanding the still-mysterious phenomenon of sequestered proton gradients which strong evidence suggests can energize ATP formation in chloroplast organelle membranes. Results from several laboratories support the notion that chloroplasts can couple the energy of H{sup +} gradients. Research in may lab has, since 1983, been deeply involved in a two-pronged approach, (A) identifying and quantitating sequestered proton buffering groups and (B) trying to elucidate just how the sequestered H{sup +} gradient is maintained and what regulates the switching between the localized and delocalized coupling modes. One aspect we have worked on under DOE auspices is the question whether the localized H{sup +} coupling, routinely detected in my lab by a protocol which measures the number of single-turnover flashes (usually fired at 5 Hz) required to reach the energization threshold for ATP formation, can continue in steady illumination. It is possible to consider that a localized coupling response could be observed in the initial energization transient followed obligatorily by the sustained H{sup +} gradient equilibrating with the lumen bulk phase. If that occurred, it would have very important ramifications as to how one evaluates the possible physiological meaning of localized'' coupling. To test this, we developed a steady illumination protocol which is briefly discussed.
Date: January 1, 1991
Creator: Dilley, R.A.
Partner: UNT Libraries Government Documents Department

Roles of repetitive sequences

Description: The DNA of higher eukaryotes contains many repetitive sequences. The study of repetitive sequences is important, not only because many have important biological function, but also because they provide information on genome organization, evolution and dynamics. In this paper, I will first discuss some generic effects that repetitive sequences will have upon genome dynamics and evolution. In particular, it will be shown that repetitive sequences foster recombination among, and turnover of, the elements of a genome. I will then consider some examples of repetitive sequences, notably minisatellite sequences and telomere sequences as examples of tandem repeats, without and with respectively known function, and Alu sequences as an example of interspersed repeats. Some other examples will also be considered in less detail.
Date: January 1, 1991
Creator: Bell, G.I.
Partner: UNT Libraries Government Documents Department

Electromagnetic imaging of dynamic brain activity

Description: Neural activity in the brain produces weak dynamic electromagnetic fields that can be measured by an array of sensors. Using a spatio-temporal modeling framework, we have developed a new approach to localization of multiple neural sources. This approach is based on the MUSIC algorithm originally developed for estimating the direction of arrival of signals impinging on a sensor array. We present applications of this technique to magnetic field measurements of a phantom and of a human evoked somatosensory response. The results of the somatosensory localization are mapped onto the brain anatomy obtained from magnetic resonance images.
Date: January 1, 1991
Creator: Mosher, J.; Leahy, R. (University of Southern California, Los Angeles, CA (United States). Dept. of Electrical Engineering); Lewis, P.; Lewine, J.; George, J. (Los Alamos National Lab., NM (United States)) & Singh, M. (University of Southern California, Los Angeles, CA (United States). Dept. of Radiology)
Partner: UNT Libraries Government Documents Department

Phytochrome from green plants: assay, purification, and characterization

Description: Phytochrome from the chlorophyllous cells of light-grown higher plants and green algae has been isolated and characterized. We have developed a simple procedure that separates chlorophyll from phytochrome in crude extracts from green tissue thus permitting spectral measurement of the phytochrome in such extracts for the first time. Spectral and immunochemical analysis of phytochrome from green oat tissue indicates the presence of two distinct species of the molecule: a minority species (approx. 20%) that is recognized by antibodies directed against phytochrome from etiolated tissue and that has an apparent molecular mass of 124 kilodaltons (kD), the same as that of the native molecule from etiolated tissue; and a majority species (approx. 80%) that is not recognized by anti-etiolated tissue phytochrome Ig and has a Pr absorbance maximum some 14 nm shorter than its etiolated tissue counterpart. Mixing experiments have established that these different molecular species preexist in the green cell and are not the results of posthomogenization modifications. Attempts to purify the phytochrome from green tissue by immunoaffinity chromatography have been thwarted by the lack of immunological cross-reactivity referred to. We have begun to identify monoclonal antibodies specific for antigenic sites distributed throughout the length of the etiolated-tissue phytochrome polypeptide. Axenic cultures of the alga Mesotaenium have been established and preliminary spectral analysis of phytochrome isolated from these cells has been carried out.
Date: January 1, 1983
Creator: Quail, P.H.
Partner: UNT Libraries Government Documents Department

Chemical and physical characterization of the activation of ribulosebiphosphate carboxylase/oxygenase

Description: Molecular structure of ribulosebiphosphate carboxylase/oxygenase isolated from Rhodospirillium was compared with the enzyme isolated from Alcaligens eutrophus. Peptides derived from the active center of the bacterial enzyme were highly homologous with those isolated from spinach. Molecular shapes of the carboxylases were estimated using neutron scattering data. These studies suggested that the enzyme as isolated from R. rubrum is a solid prolate ellipsoid or cylinder, while the spinach enzyme resembles a hollow sphere. 1 drawing.
Date: January 1, 1983
Creator: Donnelly, M.I.; Ramakrishnan, V. & Hartman, F.C.
Partner: UNT Libraries Government Documents Department

Detection of early malignant changes in tissue cultured cells using a novel tumorigenicity assay in nude mice

Description: Cultured cells were tested for tumorigenicity in nude mice using a new test involving implantation of cells grown on small gelatin sponges. The test was applied to mouse, hamster, and human cells, and the results were compared to a conventional tumorigenicity assay (injection of cell suspensions). The sponge assay was at least as sensitive as the conventional assay in all cases tested so far. In several instances the sponge assay could detect events not seen in the standard assay. Use of the sponge assay has led to interesting possibilities for studying in vitro and early in vivo cellular changes that may be associated with the ability to form tumors. In studies with two human squamous cell carcinoma cell lines, the two assays yielded comparable results. Such cell lines might provide a system in which the lack of terminal differentiation within a cell population could be examined as a parameter of neoplastic change.
Date: January 1, 1979
Creator: Wells, R.S.; Campbell, E.W.; Holland, L.M.; Schwartzendruber, D.E. & Kraemer, P.M.
Partner: UNT Libraries Government Documents Department

Nonlinear discrete models for DNA dynamics

Description: In this paper we report the investigations on a problem related to DNA dynamics: thermal generation of localized pulses that are called solitons. The thermal generation of solitons in circular homogeneous DNA is investigated by calculating the number of solitons as a function of the absolute temperature. These calculations are effected by using two different models for the DNA molecule. In both models the parameters are chosen to match experimentally measured properties of the molecule. We find that a significant number of solitons is generated at physiological temperatures, and a T{sup 1/3} law is followed at low temperatures. 20 refs., 2 figs.
Date: August 1, 1989
Creator: Muto, V.; Scott, A.C.; Christiansen, P.L.; Lomdahl, P.S. (Los Alamos National Lab., NM (USA); Technical Univ. of Denmark, Lyngby (Denmark). Lab. of Applied Mathematical Physics & Los Alamos National Lab., NM (USA))
Partner: UNT Libraries Government Documents Department

Structure of plant bile pigments

Description: Selective peptide cleavage has provided a general procedure for the study of the structure, including stereochemistry, of plant bile pigments. The information derived from the synthesis and spectral analysis of a series of 2,3-dihydrodioxobilins allows the determination of the trans relative stereochemistry for ring A of the ..beta../sub 1/-phycocyanobilin from C-phycocyanin as well as for ring A of phytochrome. A complete structure proof of the five phycoerythrobilins attached to the ..cap alpha.. and ..beta.. subunits of B-phycoerythrin is described. One of these tetrapyrroles is doubly-peptide linked to a single peptide chain through two thioethers at the C-3' and C-18' positions. The four remaining phycoerythrobilins are singly-linked to the protein through thioethers at the C-3' position and all possess the probable stereochemistry C-2(R), C-3(R), C-3'(R), and C-16(R).
Date: December 1, 1983
Creator: Schoenleber, R.W.
Partner: UNT Libraries Government Documents Department

Mapping the human genome

Description: The following pages aim to lay a foundation for understanding the excitement surrounding the ''human genome project,'' as well as to convey a flavor of the ongoing efforts and plans at the Human Genome Center at the Lawrence Berkeley Laboratory. Our own work, of course, is only part of a broad international effort that will dramatically enhance our understanding of human molecular genetics before the end of this century. In this country, the bulk of the effort will be carried out under the auspices of the Department of Energy and the National Institutes of Health, but significant contributions have already been made both by nonprofit private foundations and by private corporation. The respective roles of the DOE and the NIH are being coordinated by an inter-agency committee, the aims of which are to emphasize the strengths of each agency, to facilitate cooperation, and to avoid unnecessary duplication of effort. The NIH, for example, will continue its crucial work in medical genetics and in mapping the genomes of nonhuman species. The DOE, on the other hand, has unique experience in managing large projects, and its national laboratories are repositories of expertise in physics, engineering, and computer science, as well as the life sciences. The tools and techniques the project will ultimately rely on are thus likely to be developed in multidisciplinary efforts at laboratories like LBL. Accordingly, we at LBL take great pride in this enterprise -- an enterprise that will eventually transform our understanding of ourselves.
Date: June 1, 1989
Partner: UNT Libraries Government Documents Department

Bone formation: The rules for fabricating a composite ceramic

Description: Bone, teeth and shells are complex composite ceramics which are fabricated at low temperature by living organisms. The detailed understanding of this fabrication process is required if we are to attempt to mimic this low temperature assembly process. The guiding principles and major components are outlined with the intent of establishing non-vital fabrication schemes to form a complex composite ceramic consisting of an organix matrix inorganic crystalline phase. 19 refs.
Date: January 1, 1990
Creator: Caplan, A.I. (Case Western Reserve Univ., Cleveland, OH (USA))
Partner: UNT Libraries Government Documents Department

Unusual hydrogen bonding patterns in AF (aminofluorene) and AAF (acetylaminofluorene) modified DNA

Description: New structures are presented for AF and AAF modified DNAs that place the carcinogen in the minor groove of a B-DNA helix. These structures employ non-Watson-Crick base pairing schemes with syn guanine at the modification site. 32 refs., 9 figs.
Date: January 1, 1989
Creator: Broyde, S.; Hingerty, B.E.; Shapiro, R. & Norman, D.
Partner: UNT Libraries Government Documents Department

Rapid regulatory control of plant cell expansion and wall relaxation

Description: The aim of this project is to elucidate the biophysical and cellular mechanisms that control plant cell expansion. At present we are attempting to characterize the kinetics of the system(s) responsible for regulatory and compensatory behavior of growing cells and tissues. This work is significantly because it indicates that biochemical loosening and biophysical stress relaxation of the wall are part of a feedback loop controlling growth. This report briefly summarizes the efforts and results of the past 12 months. In large part, we have been trying to analyze the nature of growth rate noise,'' i.e. spontaneous and often erratic variations in growth rate. We are obtaining evidence that such noise'' is not random, but rather reveals an underlying growth mechanism with complex dynamics.
Date: August 14, 1991
Creator: Cosgrove, D.J.
Partner: UNT Libraries Government Documents Department