Niche overlap and Hopfield-like interactions in generalized random Lotka-Volterra systems.

We study communities emerging from generalized random Lotka-Volterra dynamics with a large number of species with interactions determined by the degree of niche overlap. Each species is endowed with a number of traits, and competition between pairs of species increases with their similarity in trait space. This leads to a model with random Hopfield-like interactions.

Fetal Age Assessment From Primary Teeth and Long Bones.

This study evaluated traditional and expedited methods for assessing the age of fetal remains. Because of their rare occurrence, the discovery of fresh, decomposing, disfigured, or skeletal fetuses engenders heightened awareness by forensic pathologists primarily tasked with age estimation in relation to viability. With decomposed complete or isolated fetal remains, dentists focus on primary molar mineralization, whereas anthropologists perform long bone measurements along with discernment of other indicators of skeletal maturity to obtain an age estimation.

The effect of sucrose addition at dosage stage on the foam attributes of a bottle-fermented English sparkling wine.

Background: Approximately two-thirds of wine produced in the UK is bottle-fermented sparkling wine. Effervescence and foamability are key features used to assess English sparkling wine (ESW) quality. A critical, yet understudied, area of research is the potential for dosage to influence foam behaviour via associated changes in wine viscosity.

Conceptualization of a Health Care Coalition Framework in Georgia Based on the Existing Regional Coordinating Hospital Infrastructure.

The watershed events of September 11, 2001; the anthrax attacks; Hurricane Katrina; and H1N1 necessitated that the United States define alternative mechanisms for disaster response. Specifically, there was a need to shift from a capacity building approach to a capabilities based approach that would place more emphasis on the health care community rather than just first responders. Georgia responded to this initiative by creating a Regional Coordinating Hospital (RCH) infrastructure that was responsible for coordinating regional responses within their individual geographic footprint.

A community-based participatory research partnership to reduce vehicle idling near public schools.

The authors implemented and assessed the effectiveness of a public health initiative aimed at reducing traffic-related air pollution exposure of the school community at four Cincinnati public schools. A partnership was fostered with academic environmental health researchers and community members. Anti-idling campaign materials were developed and education and training were provided to school bus drivers, students, parents, and school staff.

The Bernal Lecture 2004 Are low-frequency electromagnetic fields a health hazard?

Electric power is an essential commodity of the developed world, and is critical to the continuing progress of our technology-based society, as well as to the growth of less privileged societies. In contrast to its overwhelming benefits, there is a suspicion that the magnetic component of the electromagnetic fields (EMFs) associated with power distribution and electrical appliances has adverse health effects, especially a small increased incidence of childhood leukaemia. The possibility that environmental EMFs represent a health hazard has serious economic implications for government, the electricity industry and society, as well as raising several profound scientific challenges, including, in particular, biophysical mechanisms, experimental replication and scientific uncertainty.

Alan Frederick Williams 25 May 1945 - 9 April 1992.

Alan WIlliams is noted for his seminal contributions to the field of leucocyte membrane glycoproteins (that is, differentiation antigens). He played a leading role in the development of approaches to the purification and structural analysis of cell surface antigens. His comprehensive characterization of the structure of the rat Thy-1 antigen, as well as the application of monoclonal antibodies to the designation and subsequent isolation of multiple new leucocyte antigens, were exemplary.

Are environmental electromagnetic fields genotoxic?

Long-term exposure to extremely-low-frequency electromagnetic fields (ELF EMFs) greater than 0.4 microT has been linked, by epidemiological studies, to a small elevated risk of childhood leukaemia. Laboratory-based experiments have been claimed to show that ELF EMFs induce a variety of biological responses, although these claims are controversial.

Transferrin receptor induces tyrosine phosphorylation in T cells and is physically associated with the TCR zeta-chain.

In addition to being an iron transporter, the transferrin receptor (TfR) has been shown to play a role in T cell activation. Stimulation of the TfR with specific Abs results in T cell proliferation, IL-2 secretion, and protein kinase C activation. In this paper we have analyzed early events caused by activation of the TfR.

CD7 is associated with CD3 and CD45 on human T cells.

The CD7 cluster of mAb identifies a 40-kDa glycopolypeptide that is present on a major subset of human T cells. CD7 Ag mediates an accessory pathway of T cell activation in that cross-linked CD7 mAb are mitogenic, and signals delivered via CD7 Ag stimulate integrin-mediated adhesion. We have found that the CD7 molecule is associated with a tyrosine kinase whose major substrate is CD45.

Structure of the human annexin VI gene.

We report the structure of the human annexin VI gene and compare the intron-exon organization with the known structures of the human annexin I and II genes. The gene is approximately 60 kbp long and contains 26 exons. Consistent with the published annexin VI cDNA sequence, the genomic sequence at the 3' end does not contain a canonical polyadenylation signal.

Immunotoxins containing saporin linked to different CD2 monoclonal antibodies: in vitro evaluation.

In this study we describe immunotoxins prepared with different CD2 monoclonal antibodies (mAbs) and a ribosome-inactivating protein, saporin. The CD2 immunotoxins were tested on different models. Anti-CD2-saporin conjugates inhibited protein synthesis by a neoplastic CD2+ cell line (SKW-3) and by an interleukin 2 dependent polyclonal CD2+ lymphoid cell culture (T lymphoblasts), with IC50s ranging from 10(-13) M to 10(-11) M (as saporin).

Tyrosine phosphorylation of alpha tubulin in human T lymphocytes.

N-terminal sequencing of the 55- and 50-kDa polypeptides affinity purified on a phosphotyrosine monoclonal antibody column from activated Jurkat T cells identified alpha and beta tubulin. Two-dimensional gel analysis indicated that alpha tubulin was directly phosphorylated on tyrosine. beta Tubulin was not detectably tyrosine phosphorylated but was precipitated by anti-phosphotyrosine (PTyr) antibody by virtue of its association with the alpha subunit as a heterodimer.

Comparative analysis of phosphotyrosyl polypeptides in normal and leukemic human T lymphocytes activated via CD3 or CD2.

Phosphotyrosyl polypeptides induced following CD3- or CD2- specific antibody stimulation were analysed in different human T cell lines by immunoblotting or by immunoprecipitation of 32P-labelled cell lysates using a phosphotyrosine-specific monoclonal antibody. In Jurkat cells, resting peripheral T lymphocytes, T lymphoblasts, CD8+ T lymphoblasts and a CD4+ T cell clone, CD3 stimulation induced a strong but transient tyrosine phosphorylation of at least 15 polypeptides. However, in peripheral T cells and T blasts, the kinetics of phosphorylation were considerably slower than in Jurkat cells.

Physical association of CD5 and the T cell receptor/CD3 antigen complex on the surface of human T lymphocytes.

The physical association of CD5 and the T cell antigen receptor (TcR)/CD3 complex on the surface of intact human lymphocytes was investigated using co-capping experiments and fluorescence resonance energy transfer (FRET) analyses. Antibody-induced capping of CD5 or CD3 and double indirect immunofluorescence labeling revealed a specific co-localization of a significant fraction of CD3 and CD5 molecules on the T cell surface. By means of FRET measurements we studied further the physical proximity of CD5 and the TcR/CD3 complex at the surface of normal lymphocytes.

CD3 and CD2 antigen-mediated CD3 gamma-chain phosphorylation in permeabilized human T cells. Regulation by cytosolic phosphatases.

The role of cytosolic and membrane-associated phosphatases in regulating dephosphorylation of the CD3 antigen gamma-chain has been investigated using streptolysin-O-permeabilized T lymphoblasts and Jurkat T leukaemia cells. Permeabilization of T cells caused a rapid extrusion of cytosolic type 2A phosphatases, but a membrane-associated phosphorylase phosphatase activity remained inside the cells. This activity had the properties characteristic of type 2A phosphatases, being resistant to inhibition by type 1 phosphatase inhibitors, though it was inhibited in a time-dependent manner by ATP or by non-hydrolysable ATP analogues, but not by GTP, CTP, ITP or PPi.

A growth-dependent post-translational modification of annexin VI.

Annexin VI (p68, 67-kDa calelectrin) is a member of a family of Ca2+/phospholipid-binding proteins, that includes p35 (annexin I) and p36 (annexin II), the major cellular substrates for phosphorylation by the epidermal growth factor receptor and pp60v-src tyrosine kinase activities, respectively. We report here that like annexins I and II, annexin VI is phosphorylated in vivo, but that in contrast, annexin VI phosphorylation is associated with cell growth. In both Swiss 3T3 fibroblasts and human T-lymphoblasts the pattern of phosphorylation followed an almost identical profile.

Evidence for an association between the T cell receptor/CD3 antigen complex and the CD5 antigen in human T lymphocytes.

In this work we report that CD5, a T cell accessory activation antigen and receptor for the B cell surface protein CD72, is associated with the T cell antigen receptor (TcR)/CD3 complex in human T lymphocytes. In vitro phosphorylation of either CD3 or CD5 immunoprecipitates prepared from CD3-stimulated Jurkat and peripheral blood T cells in the presence of the detergent polyoxyethelene 10 oleyl ether (Brij96) showed, unexpectedly, an identical pattern of five phosphopolypeptides of 70, 59, 56, 21 and 18 kDa, respectively. Peptide mapping of the five bands demonstrated that the same protein kinase substrates co-precipitated with both CD3 and CD5 and that the majority of the protein phosphorylation occurred on tyrosine residues.

CD5 is phosphorylated on tyrosine after stimulation of the T-cell antigen receptor complex.

When T cells are activated by the T-cell antigen receptor, a number of cellular proteins are phosphorylated on tyrosine. We investigated whether any of these proteins were present on the surface of activated T cells. Using the human leukemic T-cell line Jurkat and normal peripheral blood lymphocytes, we identified a 67-kDa cell surface glycoprotein in anti-phosphotyrosine immunoprecipitates, after treatment of the cells with CD3 antibody.

A model of the structure of human annexin VI bound to lipid monolayers.

Annexin VI is an eight repeat member of the annexin family of proteins which are both water soluble and bind to negatively charged phospholipids in a calcium-dependent manner. Here we present a model for annexin VI based on fitting the three-dimensional structure of two annexin V molecules (Huber (1990) EMBO J. 9, 3867-3874) to the two-dimensional stain-excluding density of lipid-bound annexin VI (Newman (1989) J.

Three dimensional structure of the transmembrane region of the proto-oncogenic and oncogenic forms of the neu protein.

The neu proto-oncogene may be converted into a dominantly transforming oncogene by a single point mutation. Substitution of a valine residue at position 664 in the transmembrane region with glutamic acid activates the tyrosine kinase of the molecule and is associated with increased receptor dimerization. Previously we have proposed a model in which the glutamic acid side chain stabilizes receptor dimerization by hydrogen bonding.

Human CD2 is functional in CD2 transgenic mice.

We aimed to study the biochemical consequences of T-cell activation via the CD2 antigen in mouse T cells. The lack of stimulatory monoclonal antibodies against the mouse CD2 antigen led us to analyse this problem in transgenic mice carrying and expressing the human CD2 gene. Monoclonal antibodies to the human CD2 antigen that were mitogenic for human T cells induced proliferation of mouse T cells from the CD2 transgenic mice.

The T cell receptor/CD3 complex and CD2 stimulate the tyrosine phosphorylation of indistinguishable patterns of polypeptides in the human T leukemic cell line Jurkat.

Stimulation of the T cell receptor (TcR)/CD3 complex of Jurkat T cells with a monoclonal antibody to the CD3 epsilon chain induced the tyrosine phosphorylation of multiple polypeptides, ranging in size from 21 to 155 kDa. The protein tyrosine phosphorylation was characterized by its rapidity and its transient nature, returning to baseline levels by 60 min. Protein tyrosine kinase activity was also induced when the Jurkat T cells were stimulated with a mitogenic pair of antibodies directed against CD2.

Amino acid sequence analysis of the annexin super-gene family of proteins.

The annexins are a widespread family of calcium-dependent membrane-binding proteins. No common function has been identified for the family and, until recently, no crystallographic data existed for an annexin. In this paper we draw together 22 available annexin sequences consisting of 88 similar repeat units, and apply the techniques of multiple sequence alignment, pattern matching, secondary structure prediction and conservation analysis to the characterisation of the molecules.