Novel field sampling procedure for the determination of methiocarb residues in surface waters from rice fields.

Methiocarb was extracted from surface water samples collected at experimental rice field sites in Louisiana and Texas. The sampling system consisted of a single-stage 90-mm Empore extraction disk unit equipped with a battery-powered vacuum pump. After extraction, the C-18 extraction disks were stored in an inert atmosphere at -10 degrees C and shipped overnight to the laboratory.

A role for N-WASP in invasin-promoted internalisation.

Phagocytosis of Yersinia pseudotuberculosis occurs through interaction of the bacterial protein invasin with beta1-integrins. Here we report that N-WASP plays a role in internalisation of an invasin-expressing, avirulent strain of Y. pseudotuberculosis.

Kinesin-dependent movement on microtubules precedes actin-based motility of vaccinia virus.

Vaccinia virus, a close relative of the causative agent of smallpox, exploits actin polymerization to enhance its cell-to-cell spread. We show that actin-based motility of vaccinia is initiated only at the plasma membrane and remains associated with it. There must therefore be another form of cytoplasmic viral transport, from the cell centre, where the virus replicates, to the periphery.

A phosphatidylinositol 3-kinase-independent insulin signaling pathway to N-WASP/Arp2/3/F-actin required for GLUT4 glucose transporter recycling.

Recruitment of intracellular glucose transporter 4 (GLUT4) to the plasma membrane of fat and muscle cells in response to insulin requires phosphatidylinositol (PI) 3-kinase as well as a proposed PI 3-kinase-independent pathway leading to activation of the small GTPase TC10. Here we show that in cultured adipocytes insulin causes acute cortical localization of the actin-regulatory neural Wiskott-Aldrich syndrome protein (N-WASP) and actin-related protein-3 (Arp3) as well as cortical F-actin polymerization by a mechanism that is insensitive to the PI 3-kinase inhibitor wortmannin. Expression of the dominant inhibitory N-WASP-DeltaWA protein lacking the Arp and actin binding regions attenuates the cortical F-actin rearrangements by insulin in these cells.

An emergency department-based randomized trial of nonbronchoscopic bronchoalveolar lavage for early pathogen identification in severe community-acquired pneumonia.

Study Objectives: Many patients with community-acquired pneumonia are treated empirically without an aggressive search for causative pathogens, an approach adopted largely because of the costs and difficulties encountered during efforts to identify the causative organisms. Blood and sputum cultures are not sensitive, and the more invasive techniques of bronchoscopy and lung biopsy are generally time consuming and not cost-effective. The technique of nonbronchoscopic bronchoalveolar lavage (BAL) has been shown to accurately diagnose the causes of nosocomial pneumonia.

Both calmodulin and the unconventional myosin Myr4 regulate membrane trafficking along the recycling pathway of MDCK cells.

In epithelial cells, endocytosed transferrin and its receptor, which cycle basolaterally, have been shown to transit through recycling endosomes which can also be accessed by markers internalized from the apical surface. In this work, we have used an in vitro assay to follow transfer of an endocytosed marker from apical or basolateral early endosomes to recycling endosomes labeled with transferrin. We show that calmodulin (CaM) function is necessary for transfer and identified myr4, a member of the unconventional myosin superfamily known to use CaM as a light chain, as a possible target protein for CaM.

Viral transport and the cytoskeleton.

In the past decade, studies into the way in which intracellular bacterial pathogens hijack and subvert their hosts have provided many important insights into regulation of the actin cytoskeleton and cell motility, in addition to increasing our understanding of the infection process. Viral pathogens, however, may ultimately unlock more cellular secrets as they are even more dependent on their hosts during their life cycle.

Surfing pathogens and the lessons learned for actin polymerization.

A number of unrelated bacterial species as well as vaccinia virus (ab)use the process of actin polymerization to facilitate and enhance their infection cycle. Studies into the mechanism by which these pathogens hijack and control the actin cytoskeleton have provided many interesting insights into the regulation of actin polymerization in migrating cells. This review focuses on what we have learnt from the actin-based motilities of Listeria, Shigella and vaccinia and discusses what we would still like to learn from our nasty friends, including enteropathogenic Escherichia coli and Rickettsia

In silico studies of energy metabolism of normal and diseased heart.

Biotechnology research is developing into genomic analyses that involve the simultaneous monitoring of thousands of genes. The development of various bioinformatics resources that provide efficient access to information is necessary. We have used single-pass sequencing of randomly selected cDNA clones to generate expressed sequence tags (ESTs).

Actin assembly induced by polylysine beads or purified phagosomes: quantitation by a new flow cytometry assay.

Background: Actin assembly on biological membranes is a poorly understood process. We have previously shown that phagosomal membranes could induce actin assembly in the presence of thymosin beta4 (an actin sequestering protein that inhibits nonspecific nucleation), via the barbed ends of actin filaments.

Methods: Here, we have developed an in vitro system based on fluorescein-labeled G (monomeric) actin and flow cytometry analysis, which allowed us to quantify de novo actin assembly on the cytoplasmic side of purified phagosomes.

Vaccinia virus infection disrupts microtubule organization and centrosome function.

We examined the role of the microtubule cytoskeleton during vaccinia virus infection. We found that newly assembled virus particles accumulate in the vicinity of the microtubule-organizing centre in a microtubule- and dynein-dynactin complex-dependent fashion. Microtubules are required for efficient intracellular mature virus (IMV) formation and are essential for intracellular enveloped virus (IEV) assembly.

A complex of N-WASP and WIP integrates signalling cascades that lead to actin polymerization.

Wiskott-Aldrich syndrome protein (WASP) and N-WASP have emerged as key proteins connecting signalling cascades to actin polymerization. Here we show that the amino-terminal WH1 domain, and not the polyproline-rich region, of N-WASP is responsible for its recruitment to sites of actin polymerization during Cdc42-independent, actin-based motility of vaccinia virus. Recruitment of N-WASP to vaccinia is mediated by WASP-interacting protein (WIP), whereas in Shigella WIP is recruited by N-WASP.

Parasympathetic and sympathetic influences in neuro-occupation pertaining to play.

The occupation of play is a vital and necessary component of the developing child. Many factors underlie the overall ability of the child to engage in play, such as the physical and social environment and the child's desire for exploration. Using neuro-occupation as a foundational framework, the current paper addresses the relationship of play and the autonomic nervous system.

Violence in the emergency department: a survey of health care workers.

Background: Violence in the workplace is an ill-defined and underreported concern for health care workers. The objectives of this study were to examine perceived levels of violence in the emergency department, to obtain health care workers' definitions of violence, to determine the effect of violence on health care workers and to determine coping mechanisms and potential preventive strategies.

Methods: A retrospective written survey of all 163 emergency department employees working in 1996 at an urban inner-city tertiary care centre in Vancouver.

Actin-based motility of vaccinia virus mimics receptor tyrosine kinase signalling.

Studies of the actin-based motility of the intracellular pathogens Listeria monocytogenes and Shigella flexneri have provided important insight into the events occurring at the leading edges of motile cells. Like the bacteria Listeria and Shigella, vaccinia virus, a relative of the causative agent of smallpox, uses actin-based motility to spread between cells. In contrast to Listeria or Shigella, the actin-based motility of vaccinia is dependent on an unknown phosphotyrosine protein, but the underlying mechanism remains obscure.

Leucine 255 of Src couples intramolecular interactions to inhibition of catalysis.

The activity of the c-Src tyrosine kinase is regulated through intramolecular interactions between the catalytic and SH2/SH3 domains. However, the exact mechanism by which this occurs remains obscure. In the crystal structure of c-Src, the peptide that links the SH2 and catalytic domain (SH2-CD linker) is sandwiched between the latter and the SH3 domain.

Molecular characterization of caveolin association with the Golgi complex: identification of a cis-Golgi targeting domain in the caveolin molecule.

Caveolins are integral membrane proteins which are a major component of caveolae. In addition, caveolins have been proposed to cycle between intracellular compartments and the cell surface but the exact trafficking route and targeting information in the caveolin molecule have not been defined. We show that antibodies against the caveolin scaffolding domain or against the COOH terminus of caveolin-1 show a striking specificity for the Golgi pool of caveolin and do not recognize surface caveolin by immunofluorescence.

Effects of a thermoplastic foot orthosis on patellofemoral pain in a collegiate athlete: a single-subject design.

Study Design: Single-subject, A-B-A-B format.

Objective: To evaluate the effects of a foot orthosis on pain and function by controlling forefoot pronation.

Background: Foot orthoses have been recommended to treat patellofemoral pain by controlling excessive pronation, but few studies have used an experimental design to validate this approach.

Interactions between vaccinia virus IEV membrane proteins and their roles in IEV assembly and actin tail formation.

The intracellular enveloped form of vaccinia virus (IEV) induces the formation of actin tails that are strikingly similar to those seen in Listeria and Shigella infections. In contrast to the case for Listeria and Shigella, the vaccinia virus protein(s) responsible for directly initiating actin tail formation remains obscure. However, previous studies with recombinant vaccinia virus strains have suggested that the IEV-specific proteins A33R, A34R, A36R, B5R, and F13L play an undefined role in actin tail formation.

In vitro approaches to study actin and microtubule dependent cell processes.

Actin and microtubules represent complex polymer systems that play essential roles during many cellular processes including chromosome segregation, cytokinesis and motility. The dynamic nature of actin and microtubules together with their regulation by a myriad of proteins makes their study both fascinating and challenging. Over the past few years there has been an increasing move towards development of in vitro systems to facilitate the elucidation of the molecular basis of actin and microtubule dependent cell processes.

Tyrosine phosphorylation is required for actin-based motility of vaccinia but not Listeria or Shigella.

Studies of the actin-based motility of pathogens have provided important insights into the events occurring at the leading edge of motile cells [1] [2] [3]. To date, several actin-cytoskeleton-associated proteins have been implicated in the motility of Listeria or Shigella: vasodilator-stimulated phosphoprotein (VASP), vinculin and the actin-related protein complex of Arp2 and Arp3 [4] [5] [6] [7]. To further investigate the underlying mechanism of actin-tail assembly, we examined the localization of components of the actin cytoskeleton including Arp3, VASP, vinculin and zyxin during vaccinia, Listeria and Shigella infections.

Interaction of vaccinia virus with the actin cytoskeleton.

Vaccinia virus infection results in large rearrangements of the host actin cytoskeleton including the formation of actin tails that are strikingly similar to those seen in Listeria, Shigella and Rickettsia infections. Using actin polymerization as the driving force the intracellular enveloped form of the vaccinia virus (IEV) is propelled on the tip of actin tails at a speed of 2.8 microns/min, both intra- and intercellularly.