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T Willis

Publications and source records attributed to T Willis.

9 recordsLinked to original sources
PubMed2001

Immune-type receptor genes in zebrafish share genetic and functional properties with genes encoded by the mammalian leukocyte receptor cluster.

An extensive, highly diversified multigene family of novel immune-type receptor (nitr) genes has been defined in Danio rerio (zebrafish). The genes are predicted to encode type I transmembrane glycoproteins consisting of extracellular variable (V) and V-like C2 (V/C2) domains, a transmembrane region and a cytoplasmic tail. All of the genes examined encode immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic tail. Radiation hybrid panel mapping and analysis of a deletion mutant line (b240) indicate that a minimum of approximately 40 nitr genes are contiguous in the genome and span approximately 0.6 Mb near the top of zebrafish linkage group 7. One flanking region of the nitr gene complex shares conserved synteny with a region of mouse chromosome 7, which shares conserved synteny with human 19q13.3-q13.4 that encodes the leukocyte receptor cluster. Antibody-induced crosslinking of Nitrs that have been introduced into a human natural killer cell line inhibits the phosphorylation of mitogen-activated protein kinase that is triggered by natural killer-sensitive tumor target cells. Nitrs likely represent intermediates in the evolution of the leukocyte receptor cluster.

Amino Acid Sequence↗
PubMed2001

Temperature-modulated array high-performance liquid chromatography.

Using novel monolithic poly(styrene-divinylbenzene) capillary columns with an internal diameter of 0.2 mm, we demonstrate for the first time the feasibility of constructing high-performance liquid chromatography arrays for the detection of mutations by heteroduplex analysis under partially denaturing conditions. In one embodiment, such an array can be used to analyze one sample simultaneously at different temperatures to maximize the detection of mutations in DNA fragments containing multiple discrete melting domains. Alternatively, one may inject different samples onto columns kept at the same effective temperature. Further improvements in throughput can be obtained by means of laser-induced fluorescence detection and the differential labeling of samples with up to four different fluorophores. Major advantages of monolithic capillary high-performance liquid chromatographic arrays over their capillary electrophoretic analogs are the chemical inertness of the poly(styrene-divinylbenzene) stationary phase, the physical robustness of the column bed due to its covalent linkage to the inner surface of the fused silica capillary, and the feasibility to modify the stationary phase thereby allowing the separation of compounds not only on the principle of size exclusion, but also adsorption, distribution, and ion exchange. Analyses times are on the order of a few minutes and turnaround time is extremely short as there is no need for the replenishment of the separation matrix between runs.

Chromatography, High Pressure Liquid↗
PubMed1984

The role of anaerobic bacteria in some extra-abdominal infections including person-to-person contamination.

With the possible exception of campylobacter enteritis, anaerobic infections are not transmitted from person to person, and do not present problems of hospital cross-infection. There are a number of situations, however, in which non-clostridial anaerobic infections may develop as result of person to person contamination of a compromised "recipient" with normal anaerobic bacterial flora from a healthy "donor". Some of these are briefly discussed.

Abscess↗
PubMedDate not supplied

Biochemical characterization of atroxase and nucleotide sequence encoding the fibrinolytic enzyme.

Atroxase, isolated from the venom of Crotalus atrox (western diamondback rattlesnake), is a non-hemorrhagic protease which has fibrinolytic activity in vitro and in vivo. Fibrin solubilization occurs primarily from the hydrolysis of alpha-polymer and unpolymerized alpha- and beta-chains. The enzyme also cleaves the A alpha-chain of fibrinogen first, followed by the B beta-chain, and shows no effect on the gamma-chain. Although crude venom induces platelet aggregation, atroxase demonstrated no ability to induce or inhibit aggregation. Intravenous administration of atroxase at a dosage of 6.0 mg/kg resulted in thrombolysis within 1 hr followed by recanalization. The primary structure of atroxase was deduced from the cDNA encoding the atroxase protein. The venom glands of C. atrox were used to prepare a cDNA library. Degenerate oligonucleotides were synthesized based on the partial amino acid sequence of atroxase and were used as primers in the polymerase chain reaction to amplify overlapping cDNA fragments from the C. atrox cDNA library. The resulting cDNA fragments were subcloned, sequenced, and translated. The final nucleotide sequence shows high homology to previously described primary structures of non-hemorrhagic fibrinolytic proteases isolated from snake venom. The base sequence of cDNA obtained from colony hybridization also showed comparable results to the cDNA fragment amplified by PCR.

Amino Acid Sequence↗