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PubMed1998

Intrinsic dendritic cell abnormalities in Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome (WAS) is an X-linked disorder characterized by immune deficiency, eczema, and microthrombocytopenia. Biochemical evidence indicates that the Wiskott-Aldrich syndrome protein (WASp) is involved in regulating the actin cytoskeleton. Here we report that WAS dendritic cells (DC) have an immunophenotype very similar to normal DC. However, as a consequence of an intrinsically abnormal cytoarchitecture, they are unable to polarize normally and have severely reduced translocational motility in vitro. These findings indicate that WASp is an essential effector for Cdc-42-mediated polarization of primary hematopoietic cells, and suggest that a significant component of the clinical phenotype of WAS could arise from peripheral DC dysmotility and aberrant immune cell trafficking in vivo. Intrinsic dysfunction of the DC population may also have an important role in the pathogenesis of other primary immunodeficiency syndromes, while induced changes in DC cytoskeletal signaling pathways may contribute to the initiation of acquired immunological and inflammatory disorders.

Actins↗

PubMed1999

The SH3 domain of Bruton's tyrosine kinase displays altered ligand binding properties when auto-phosphorylated in vitro.

Btk is a member of the Tec family of protein tyrosine kinases expressed in B cells. It is stimulated following cross-linking of the B cell receptor which leads to the autophosphorylation of a specific residue in the SH3 domain, Y223. Previous work using Btk-derived fusion proteins has shown that the Btk SH3 domain binds to c-Cbl and Wiskott-Aldrich syndrome protein (WASP) in vitro. We show here that when the Btk SH3 domain fusion protein is autophosphorylated, its ability to take part in protein interactions is altered as compared to the non-phosphorylated fusion protein. Although the phosphorylated Btk SH3 domain still binds c-Cbl, it no longer binds WASP and instead acquires a high affinity for kinase-active Syk. The region of Syk responsible for this interaction is contained within its C terminus, suggesting a novel mechanism by which these proteins may interact.

Agammaglobulinaemia Tyrosine Kinase↗

PubMed2002

Wiskott-Aldrich syndrome in Argentina: 17 unique, including nine novel, mutations.

Wiskott-Aldrich syndrome (WAS), is an X-linked immunodeficiency disease caused by mutations of the WAS protein (WASP) gene, characterized by thrombocytopenia, eczema and recurrent infections. X-linked thrombocytopenia (XLT) is a milder form with only platelet abnormalities. Cumulative mutation data have revealed that WASP genotypes are highly variable among WAS patients. By SSCP analysis, we determined the location of the mutation in 23 WAS patients from 17 unrelated families with variable clinical phenotypes. Direct sequence analysis of genomic DNA showed 9 novel mutations (Q52H, G70W, 393del7, Ex 7 Ex11del, IVS 8+1G-->C, 925delG, 959ins38, 1380del8, and IVS 2+2T-->C) and 8 known mutations distributed throughout the WAS gene. This is the first report of WAS gene mutations from a Latin American country.

Argentina↗

PubMed2006

Ribosomal protein L10 interacts with the SH3 domain and regulates GDNF-induced neurite growth in SH-SY-5y cells.

The 24.5 kDa ribosomal protein L10 (RP-L10), which was encoded by QM gene, was known to interact with the SH3 domain of Yes kinase. Herein, we demonstrate that RP-L10 interacts with the SH3 domain of Src and activates the binding of the Nck1 adaptor protein with skeletal proteins such as the Wiskott-Aldrich Syndrome Protein (WASP) and WASP interacting protein (WIP) in neuroblastoma cell line, SH-SY-5y. The RP-L10 was associated with the SH3 domains of Src and Yes. It is shown that two different regions of RP-L10 are associated with the Src-SH3. The effect of ectopic RP-L10 expression on neuronal cell scaffolding was explored in cells transiently transfected with QM. SH-SY-5y human neuroblastoma cells transfected with QM were considerably more susceptible to neurite outgrowth induced by glial cell line-derived neurotrophic factor (GDNF). However, RP-L10 did not directly interact with actin assembly. Taken together, these results suggest that the RP-L10 may positively regulate the GDNF/Ret-mediated signaling of neurite outgrowth in the neuroblastoma cell line, SH-SY-5y.

Actins↗

PubMed2004

The contact toxicity of indoxacarb and five other insecticides to Orius insidiosus (Hemiptera: Anthocoridae) and Aphidius colemani (Hymenoptera: Braconidae), beneficials used in the greenhouse industry.

The contact toxicity of indoxacarb, abamectin, endosulfan, insecticide soap, S-kinoprene and dimethoate to Orius insidiosus (Say) and Aphidius colemani Viereck were studied in the laboratory. These beneficials are often used in the greenhouses to manage various insect pests. Indoxacarb is slow acting and therefore, to estimate lethal dosages, observations should be continued for several days until data stabilize. Seven days after treatment, the LC50 was 0.119 g AI litre(-1) for O insidiosus adults and 0.019 g AI litre(-1) for A colemani. At that time, the recommended field concentration was 0.479 times the LC50 for O insidiosus adults and three times the LC50 for A colemani. In contrast, indoxacarb had no adverse effect on the reproductive capacity of wasps surviving a treatment or the developing wasps in the aphid mummy. Among the other insecticides S-kinoprene was the most innocuous while dimethoate was the most toxic to the two beneficials. The other insecticides had overlapping toxicities.

Animals↗

PubMed2004

Preliminary investigation of electrodynamic charged droplet processing to couple capillary liquid chromatography with matrix-assisted laser desorption/ionization mass spectrometry.

Charged droplet processing methodology, that utilizes electrodynamic levitation technology to control the trajectories of picoliter volume charged droplets and deliver them to a target plate at atmospheric pressure, has been developed. Termed wall-less sample preparation (WaSP), this methodology offers several features that could prove beneficial to the preparation of sample spots from separation column effluents for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. These features include solute pre-concentration factors of 10(1) to 10(3) due to volatile solvent evaporation prior to droplet deposition onto the target plate, high spatial accuracy of the deposition position of each processed droplet (+/-5 microm), and the ability to prepare sample spots as small as 20 microm in diameter from a single droplet. Here a new mode of operation of this methodology is described and used as an offline post-column pre-concentrating interface between capillary liquid chromatography (capLC) and a target plate for offline MALDI-MS. Using a fraction from the capLC separation of peptides produced by the proteolytic digestion of the protein cytidine 5'-triphosphate:phosphocholine cytidylyltransferase, MALDI sample spots were prepared using the dried-droplet method, direct piezoelectric droplet dispensing, and the processing of piezo-dispensed droplets by WaSP. The sample spot morphology was investigated using light microscopy, and peptide ion abundances produced by MALDI were measured using time-of-flight (TOF) MS. The advantages of developing an online capLC/WaSP interface with MALDI-MS in the future are discussed along with some of the challenges that may be encountered in such an endeavor.

Choline-Phosphate Cytidylyltransferase↗

PubMed1997

Absence of odour learning in the stemborer parasitoid Cotesia flavipes

Parasitic wasps are commonly found to learn olfactory and visual cues that are associated with successful host location. For many parasitoids the cues that are associated with hosts vary in space and time, and are therefore unpredictable. An ability to learn allows the wasp to concentrate on those cues that will lead it to new hosts most effectively in a particular area. In contrast, parasitoids that forage in a predictable homogeneous environment and/or make only a few foraging decisions do not need to learn and should rely on innate responses to specific cues. The role of learning in host foraging was studied in Cotesia flavipes (Hymenoptera: Braconidae), a parasitoid of stemborer larvae with an ecology where learning is expected to be of low adaptive value. There was no evidence that C. flavipes uses odour learning in host-micro-habitat location. There was no significant effect of the development and emergence environment on the response level or preference towards the odour of infested plants. Neither was there evidence that experience with a particular plant-host complex during foraging influences subsequent foraging decisions in C. flavipes females. The absence of learning in C. flavipeswhich seems an exception among the parasitoids studied, is discussed in relation to its ecology.

Journal Article↗

PubMed1998

Local mate competition, variable fecundity and information use in a parasitoid.

Experiments with sex allocation in parasitic wasps offer excellent opportunities for testing how the way in which organisms process information about their environment influences behaviour. If mating takes place in temporary patches, where only a small number of females produce offspring, then sex allocation theory predicts a female-biased sex ratio. When females lay different numbers of offspring in a patch, females that produce relatively fewer offspring should lay a less female-biased, or even male-biased, sex ratio. Recent theoretical models have predicted that the exact form of this relationship depends upon whether females know only their own clutch size (self knowledge) or also the clutch sizes laid by the other females on the patch (complete knowledge). We tested the predictions of these models by examining sex allocation when two females of the parasitoid wasp Nasonia vitripennis oviposited simultaneously on a patch. The offspring sex ratio (proportion of males) produced by a female was: (1) negatively correlated with the number of offspring that she laid; and (2) positively correlated with the body size of the other female on the patch. Larger females matured more eggs and laid more offspring in the experimental patch. This suggests that, as predicted by the complete knowledge model, the offspring sex ratio laid by a female became more female biased as she laid a greater proportion of the total offspring laid on the patch. Furthermore, females use the body size of other females to assess the clutch sizes that these will lay. Copyright 1998 The Association for the Study of Animal Behaviour

Journal Article↗

PubMed1999

Avoidance of superparasitism: a matter of learning?

Superparasitism (laying eggs into parasitized hosts) by solitary parasitoids was regarded for a long time as a mistake on the part of the foraging parasitoid, but is now widely accepted as often adaptive. In Venturia canescens the rate of avoidance of superparasitism has been shown to rise over the first 20 min from the deposition of the first egg, possibly because of a constraint in the detectability of the marker used to label parasitized hosts. Here, we show that the increase in avoidance of superparasitism with time is the result of a female's experience of hosts in the interval between laying an egg in a host and re-encountering that same host. Wasps deprived of hosts in this interval showed no avoidance of superparasitism; those given healthy hosts every 3 min during this interval showed increasing avoidance of superparasitism with time. Furthermore, the marker was detectable in a host within 3 min of oviposition. The results suggest that wasps quickly acquire information about the abundance of healthy hosts in their environment, and base their decision to superparasitize on this information. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed1999

Gregarious development in alysiine parasitoids evolved through a reduction in larval aggression.

Population genetic models have suggested that siblicide between the larvae of parasitoid wasps, once gained, can be lost only under stringent conditions, making transitions from solitary to gregarious development rare. However, phylogenetic studies suggest that gregarious development has evolved on numerous occasions, although the mechanisms are largely unknown. We report experiments, on two morphologically similar species of alysiine braconids, directed at an understanding of how gregarious development evolved in one subfamily. We compared the oviposition behaviour and development of Aphaereta genevensis and A. pallipes in the laboratory, on the host Drosophila virilis. Aphaereta genevensis usually lays a single egg in each host, and only a single wasp usually develops successfully even when several eggs are laid. However, A. pallipes often lays more than one egg in each host, and several offspring often complete development. Dissections of superparasitized hosts showed that this difference is accompanied by differences in larval behaviour: first-instar A. genevensis use their sharp mandibles to kill other parasitoid eggs or larvae in the same host. First-instar A. pallipes also have sharp mandibles, but do not attack conspecific larvae, suggesting that siblicide might have been lost by a simple change in larval behaviour. Aphaereta genevensis shows some features that may have helped select for reduction in larval aggression in the subfamily: a longer development time, multiple egg clutches and incomplete brood reduction. Aphaereta spp. show great promise as model systems for studying the evolution of siblicide. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed2000

Arp2/3 complex-independent actin regulatory function of WAVE.

We report that WAVE1/Scar1, a WASP-family protein that functions downstream of Rac in membrane ruffling, can induce part of the reorganization of the actin cytoskeleton without Arp2/3 complex. WAVE1 has been reported to associate and activate Arp2/3 complex at its C-terminal region that is rich in acidic residues. The deletion of the acidic residues abolished the interaction with and the activation ability of Arp2/3 complex. The expression of the mutant WAVE1 lacking the acidic residues (DeltaA), however, induced actin-clustering in cells as the wild-type WAVE1 did. In addition, this actin-clustering could not be suppressed by the coexpression of the Arp2/3 complex-sequestering fragment (CA-region) derived from N-WASP, which clearly inhibits Rac-induced membrane ruffling. This study therefore demonstrates that WAVE1 reorganizes the actin cytoskeleton not only through Arp2/3 complex but also through another unidentified mechanism that may be important but has been neglected thus far.

3T3 Cells↗

PubMedDate not supplied

A novel protocol to identify mutations in patients with wiskott-Aldrich syndrome.

Mutations of WASP (Wiskott-Aldrich syndrome protein) underlie the severe immunodeficiency/platelet disorder Wiskott-Aldrich syndrome (WAS) and its milder variant X-linked thrombocytopenia (XLT). The affected gene, a 12-exon structure on the X-chromosome, is expressed exclusively in blood cells. The encoded product WASP is a 502-amino-acid scaffolding protein that functions in stimulus-induced nucleation of actin filaments to form dynamic cell surface projections. To date, more than 150 mutations have been identified in 300 WAS/XLT kindred worldwide, generally through methodologies that include sophisticated exon screening steps such as single-strand conformation analysis. We report here a simpler protocol, which was designed for use in clinical settings to identify the mutations of newly diagnosed patients. The approach relies on directly sequencing amplified exons according to a staggered schedule based on statistical evaluation of previous cases. In a 2 1/2-year trial, samples from 28 consecutive patients were analyzed; these included 3 "blindly labeled" previously studied cases. The mutations that were identified include a broad spectrum (8 missense, 3 nonsense, 5 splice site mutations, 11 small insertion/deletions, 1 large deletion) and were broadly distributed (in 10 of the 12 exons). All mutations were verified and no discrepancies were encountered. Per patient, a mean of six DNA sequencing reactions and 6-7 h of staff effort sufficed for mutation identification and verification, indicating that the protocol is cost-effective. This cumulative experience demonstrates the suitability, reliability, and versatility of the new protocol.

Child, Preschool↗

PubMed1999

New north american records of aquatic insects as paratenic hosts of pheromermis (Nematoda: mermithidae)

Several species of aquatic insects in Trout Park Nature Preserve (Elgin, IL) were observed to have small, black spots (<0.1 mm diameter) visible within their bodies. Microscopic examination revealed these spots to be coiled juveniles of a mermithid (Nematoda: Mermithidae). Based on host habitat (seepage areas and rivulets), host species (aquatic insects), and size (mean diameter of coiled juveniles = 79 &mgr;m), it is likely that these mermithids were in the genus Pheromermis. Since adult mermithids were not found, species determination was not feasible, and the possibility of a new species cannot be ruled out. Pheromermis pachysoma and Pheromermis vesparum, however, are two species known to use aquatic insects as paratenic (i.e., transport) hosts in order to reach their definitive hosts, vespid wasps. Wasp larvae are infected by consuming the flesh of adult aquatic insects that contain the coiled juveniles of these Pheromermis spp. Of the 19 macroinvertebrate species examined in this study, Pheromermis juveniles were found in 4 caddisfly species (Hesperophylax designatus, Lepidostoma liba, Glossosoma intermedium, and Diplectrona modesta) and in 2 stonefly species (Clioperla clio and Amphinemura delosa). In addition to all 6 insect species being new host records for Pheromermis infection, this also represents the first report of nematode infection in stoneflies within the Western Hemisphere and of a Pheromermis sp. in Illinois. Among trophic groups, insect detritivores have been frequently recorded infected with coiled Pheromermis juveniles because of their direct consumption of eggs, and we also observed this for detritivores in our investigation (e.g., L. liba and A. delosa). Because C. clio was intensively infected, however, our study also provided evidence that predatory insects can be paratenic hosts. Coiled juveniles were typically present in muscle and fat body and present in almost all body regions. Not every infected paratenic host had external signs of infection; thus, dissections are required for accurate determination of infection prevalence and intensity. Our findings, in conjunction with those made in previous studies, indicate that a wide variety of aquatic insects may be used as paratenic hosts by Pheromermis. Because of their small size, it is highly likely that coiled juveniles are either overlooked or mistaken for melanized integumental wounds during field studies of aquatic insects. A more careful inspection for these coiled juveniles in aquatic insects, especially detritivores and their predators in seepage areas, would probably reveal that Pheromermis is far more common than presently documented. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

Molecular phylogeny of the Ceratosolen species pollinating Ficus of the subgenus Sycomorus sensu stricto: biogeographical history and origins of the species-specificity breakdown cases.

The 14 species of Ficus of the subgenus Sycomorus (Moraceae) are invariably pollinated by Ceratosolen species (Hym. Chalcidoidea), which in turn reproduce in the fig florets. They are distributed mostly in continental Africa, Madagascar, and the Mascarene and Comoro Islands, but 1 species extends its geographical range all over the Oriental region. Fig-pollinator relationships are usually strictly species specific, but exceptions to the 'one-to-one' rule occur within the group we studied. In order to understand both the biogeographical history of the Ceratosolen species associated with Ficus of the subgenus Sycomorus and the origins of the specificity breakdown cases, we have used cytochrome b sequences to reconstruct a phylogeny of the fig wasps. The results show that the pollinators from the Malagasy region and those from continental Africa form two distinct clades, which probably diverged after the crossing of the Mozambique Channel by an ancestral population. The Oriental wasp species show strong affinities with the African species. The two species-specificity exceptions are due to different evolutionary events. The occurrence of the two West African pollinators associated with F. sur can be explained by successive speciation events of the mutualistic partner without plant radiation. In contrast, we hypothesize that C. galili shifted by horizontal transfer from an unknown, presumably extinct, Ficus species to F. sycomorus after this native Malagasy fig species colonized Africa.

Animals↗

PubMed2005

The accumulation of a chemical cue: nest-entrance trail in the German yellowjacket, Vespula germanica.

Vespine wasps have been shown to deposit an attractive chemical in the nest entrance. Foragers use this to help locate the nest when returning to it. We determined how many individuals need to track (pass through) the entrance before the chemical is recognized. We found a logistic response as the number of tracks increased. At 200 tracks and above there was a 75-90% positive response rate to the chemical. We found no evidence of trail-marking behavior performed by foragers inside the nest entrance. We conclude that the trail is not an evolved signal, but is a cue composed of an accumulation of hydrocarbons deposited from the legs or feet of workers as they walk on a substrate. This is the first quantitative measurement of the attractiveness of the nest-entrance chemical in a social wasp.

Animals↗

PubMed2006

Parasitoid-induced mortality of Araneus omnicolor (Araneae, Araneidae) by Hymenoepimecis sp. (Hymenoptera, Ichneumonidae) in southeastern Brazil.

All species included in the Polysphincta genus-group develop as ectophagous parasitoids of active spiders, killing their hosts prior to pupation. However, little information regarding natural history and ovipositing behavior of most species are available. In this study we inspected 85 webs of Araneus omnicolor to evaluate the frequency of parasitism and host size preferences of the wasp Hymenoepimecis sp. We also described the web characteristics of normal and parasitized spiders and the wasp ovipositing behavior. About 41% of the adult females of A. omnicolor inspected were parasitized. The highest incidence of parasitism was observed among relatively small females while no egg or larva was found in large individuals. Araneus omnicolor builds a strong web composed of an orb and barrier threads, where the spider rests within a curled leaf. The parasitoid larva builds its cocoon within this refuge, and modified cocoon webs were not observed. The ovipositing behavior of Hymenoepimecis sp. was very similar to that of Hymenoepimecis argyraphaga parasitizing Leucauge argyra, including the position of the sting, the killing of a previously attached larva, and the expelling of the egg from the base of the ovipositor.

Animals↗

PubMed2002

An Alu-mediated deletion at Xp11.23 leading to Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome (WAS) is an X-linked disease characterized by thrombocytopenia, eczema and immunodeficiency of varying severity. The WASP gene, mutations of which are responsible for the phenotype, maps to Xp11.23. We describe here a patient with a large deletion in the Xp11.23 region. The deletion, which totals 15.8 kb, begins downstream of DXS1696 and encompasses 13 kb upstream of WASP and includes the distal and proximal promoters and exons 1-6. Analysis of the 5'-boundary region identified sequences missing in the Human Genome database and, as a result, the normal DNA sequence was revised to include 743 bp of novel sequence (AF466616). The patient's upstream breakpoint was localized to an AluSg element within a highly repetitive DNA region containing other Alu elements. A 26-bp recombinogenic element is located downstream of the 5' breakpoint. A 16-bp sequence just upstream of the 5' breakpoint shares close homology with the sequence that spans the 3' breakpoint in intron 6. A heptanucleotide of unknown origin, CAGGGGG, links the 5' and 3' breakpoints. To our knowledge this is the largest deletion in a WAS patient.

Alu Elements↗

PubMed2004

Herbivore attack in Casearia nitida influenced by plant ontogenetic variation in foliage quality and plant architecture.

Traits influencing plant quality as food and/or shelter for herbivores may change during plant ontogeny, and as a consequence, influence the amount of herbivory that plants receive as they develop. In this study, differences in herbivore density and herbivory were evaluated for two ontogenetic stages of the tropical tree Casearia nitida. To assess plant ontogenetic differences in foliage quality as food for herbivores, nutritional and defensive traits were evaluated in saplings and reproductive trees. Predatory arthropods were quantified and the foraging preferences of a parasitoid wasp of the genus Zacremnops were assessed. In addition, survival rates of lepidopteran herbivores (Geometridae) were evaluated experimentally. Herbivore density was three times higher and herbivory was 66% greater in saplings than in reproductive trees. Accordingly, concentrations of total foliar phenolics were higher in reproductive trees than in saplings, whereas leaf toughness, water and nitrogen concentration did not vary between ontogenetic stages. Survival rates of lepidopteran larvae exposed to natural enemies were equivalent in reproductive trees and saplings. Given the greater herbivore density on saplings, equal survival rates implied a greater foraging effort of predators on reproductive trees. Furthermore, observed foraging of parasitoid wasps was restricted to reproductive trees. I propose that herbivore density, and as a consequence, leaf damage were lower in reproductive trees than in saplings due to both traits influencing food quality, and architectural or unmeasured indirect defensive traits influencing foraging preference of natural enemies of herbivores.

Animals↗