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Search Results: 1 - 10 of 425354 matches for " Monique M. van Oers "
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Protein Tyrosine Phosphatase-Induced Hyperactivity Is a Conserved Strategy of a Subset of BaculoViruses to Manipulate Lepidopteran Host Behavior
Stineke van Houte, Vera I. D. Ros, Tom G. Mastenbroek, Nadia J. Vendrig, Kelli Hoover, Jeroen Spitzen, Monique M. van Oers
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0046933
Abstract: Many parasites manipulate host behavior to increase the probability of transmission. To date, direct evidence for parasitic genes underlying such behavioral manipulations is scarce. Here we show that the baculovirus Autographa californica nuclear polyhedrovirus (AcMNPV) induces hyperactive behavior in Spodoptera exigua larvae at three days after infection. Furthermore, we identify the viral protein tyrosine phosphatase (ptp) gene as a key player in the induction of hyperactivity in larvae, and show that mutating the catalytic site of the encoded phosphatase enzyme prevents this induced behavior. Phylogenetic inference points at a lepidopteran origin of the ptp gene and shows that this gene is well-conserved in a group of related baculoviruses. Our study suggests that ptp-induced behavioral manipulation is an evolutionarily conserved strategy of this group of baculoviruses to enhance virus transmission, and represents an example of the extended phenotype concept. Overall, these data provide a firm base for a deeper understanding of the mechanisms behind baculovirus-induced insect behavior.
The Salivary Secretome of the Tsetse Fly Glossina pallidipes (Diptera: Glossinidae) Infected by Salivary Gland Hypertrophy Virus
Henry M. Kariithi,Ikbal A. Ince,Sjef Boeren,Adly M. M. Abd-Alla,Andrew G. Parker,Serap Aksoy,Just M. Vlak ,Monique M. van Oers
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001371
Abstract: Background The competence of the tsetse fly Glossina pallidipes (Diptera; Glossinidae) to acquire salivary gland hypertrophy virus (SGHV), to support virus replication and successfully transmit the virus depends on complex interactions between Glossina and SGHV macromolecules. Critical requisites to SGHV transmission are its replication and secretion of mature virions into the fly's salivary gland (SG) lumen. However, secretion of host proteins is of equal importance for successful transmission and requires cataloging of G. pallidipes secretome proteins from hypertrophied and non-hypertrophied SGs. Methodology/Principal Findings After electrophoretic profiling and in-gel trypsin digestion, saliva proteins were analyzed by nano-LC-MS/MS. MaxQuant/Andromeda search of the MS data against the non-redundant (nr) GenBank database and a G. morsitans morsitans SG EST database, yielded a total of 521 hits, 31 of which were SGHV-encoded. On a false discovery rate limit of 1% and detection threshold of least 2 unique peptides per protein, the analysis resulted in 292 Glossina and 25 SGHV MS-supported proteins. When annotated by the Blast2GO suite, at least one gene ontology (GO) term could be assigned to 89.9% (285/317) of the detected proteins. Five (~1.8%) Glossina and three (~12%) SGHV proteins remained without a predicted function after blast searches against the nr database. Sixty-five of the 292 detected Glossina proteins contained an N-terminal signal/secretion peptide sequence. Eight of the SGHV proteins were predicted to be non-structural (NS), and fourteen are known structural (VP) proteins. Conclusions/Significance SGHV alters the protein expression pattern in Glossina. The G. pallidipes SG secretome encompasses a spectrum of proteins that may be required during the SGHV infection cycle. These detected proteins have putative interactions with at least 21 of the 25 SGHV-encoded proteins. Our findings opens venues for developing novel SGHV mitigation strategies to block SGHV infections in tsetse production facilities such as using SGHV-specific antibodies and phage display-selected gut epithelia-binding peptides.
Virology, Epidemiology and Pathology of Glossina Hytrosavirus, and Its Control Prospects in Laboratory Colonies of the Tsetse Fly, Glossina pallidipes (Diptera; Glossinidae)
Henry M. Kariithi,Monique M. van Oers,Just M. Vlak,Marc J. B. Vreysen,Andrew G. Parker,Adly M. M. Abd-Alla
Insects , 2013, DOI: 10.3390/insects4030287
Abstract: The Glossina hytrosavirus (family Hytrosaviridae) is a double-stranded DNA virus with rod-shaped, enveloped virions. Its 190 kbp genome encodes 160 putative open reading frames. The virus replicates in the nucleus, and acquires a fragile envelope in the cell cytoplasm. Glossina hytrosavirus was first isolated from hypertrophied salivary glands of the tsetse fly, Glossina pallidipes Austen (Diptera; Glossinidae) collected in Kenya in 1986. A certain proportion of laboratory G. pallidipes flies infected by Glossina hytrosavirus develop hypertrophied salivary glands and midgut epithelial cells, gonadal anomalies and distorted sex-ratios associated with reduced insemination rates, fecundity and lifespan. These symptoms are rare in wild tsetse populations. In East Africa, G. pallidipes is one of the most important vectors of African trypanosomosis, a debilitating zoonotic disease that afflicts 37 sub-Saharan African countries. There is a large arsenal of control tactics available to manage tsetse flies and the disease they transmit. The sterile insect technique (SIT) is a robust control tactic that has shown to be effective in eradicating tsetse populations when integrated with other control tactics in an area-wide integrated approach. The SIT requires production of sterile male flies in large production facilities. To supply sufficient numbers of sterile males for the SIT component against G. pallidipes, strategies have to be developed that enable the management of the Glossina hytrosavirus in the colonies. This review provides a historic chronology of the emergence and biogeography of Glossina hytrosavirus, and includes researches on the infectomics (defined here as the functional and structural genomics and proteomics) and pathobiology of the virus. Standard operation procedures for viral management in tsetse mass-rearing facilities are proposed and a future outlook is sketched.
Functional processing and secretion of Chikungunya virus E1 and E2 glycoproteins in insect cells
Stefan W Metz, Corinne Geertsema, Byron E Martina, Paulina Andrade, Jacco G Heldens, Monique M van Oers, Rob W Goldbach, Just M Vlak, Gorben P Pijlman
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-353
Abstract: Expression in the presence of either tunicamycin or furin inhibitor showed that a substantial portion of recombinant intracellular E1 and precursor E3E2 was glycosylated, but that a smaller fraction of E3E2 was processed by furin into mature E3 and E2. Deletion of the C-terminal transmembrane domains of E1 and E2 enabled secretion of furin-cleaved, fully processed E1 and E2 subunits, which could then be efficiently purified from cell culture fluid via metal affinity chromatography. Confocal laser scanning microscopy on living baculovirus-infected Sf21 cells revealed that full-length E1 and E2 translocated to the plasma membrane, suggesting similar posttranslational processing of E1 and E2, as in a natural CHIKV infection. Baculovirus-directed expression of E1 displayed fusogenic activity as concluded from syncytia formation. CHIKV-E2 was able to induce neutralizing antibodies in rabbits.Chikungunya virus glycoproteins could be functionally expressed at high levels in insect cells and are properly glycosylated and cleaved by furin. The ability of purified, secreted CHIKV-E2 to induce neutralizing antibodies in rabbits underscores the potential use of E2 in a subunit vaccine to prevent CHIKV infections.Chikungunya virus (CHIKV) is an arthropod-borne (arbo)virus that causes epidemics in Africa, India and South-East Asia [1]. Recent outbreaks in Italy in 2007 [2] and autochthonous transmission events in France in 2010 [3] exemplify the threat of continued spread of CHIKV in the Western world, which correlates with the concurrent expanding distribution of its insect vector. CHIKV is maintained in a sylvatic transmission cycle of mosquitoes, rodents and primates, with Aedes aegyti as the primary vector. However, the responsible vector causing the severe CHIKV epidemic on the Reunion Islands in 2005/2006 was Ae. albopictus [4]. This vector switch made the virus endemic in more temperate regions and resulted in the first European cases (Italy, 2007) of transmission by local
Exploring the reach and program use of hello world, an email-based health promotion program for pregnant women in the Netherlands
Johanna M van Dongen, Mireille NM van Poppel, Ivon EJ Milder, Hans AM van Oers, Johannes Brug
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-514
Abstract: The present study aimed to (1) examine the reach of Hello World and the representativeness of its users for all pregnant women in the Netherlands, (2) explore the relationship between program engagement and lifestyle characteristics, and (3) explore the relationship between the program content participants accessed (content on smoking, physical activity, and nutrition) and their lifestyle characteristics.Data from 4,363 pregnant women were included. After registration, women received an online questionnaire with demographic and lifestyle questions. To evaluate their representativeness, their demographic characteristics were compared with existing data for Dutch (pregnant) women. Women were classified on the following lifestyle characteristics: smoking, nutrition, physical activity, and pre-pregnancy weight status. Program use was tracked and the relationships between lifestyle characteristics, program engagement, and the percentage of smoking, physical activity, and nutrition questions accessed after opening a quiz were explored using Mann–Whitney U tests and Kruskal-Wallis tests.Hello World reached ±4% of its target population. Ten percent of participants were low educated and 22% immigrants. On average, women received 6.1 (SD:2.8) quiz emails and opened 32% of the associated quizzes (2.0, SD:2.1). A significant positive association was found between the number of quizzes opened and the number of healthy lifestyle characteristics. After opening a quiz, women accessed most smoking, nutrition, and physical activity questions. Significant relationships were found between several lifestyle characteristics and the percentage of smoking, physical activity, and nutrition questions accessed. However, between-group differences were small, quiz topics were largely unrelated to their lifestyle characteristics, and inconsistencies were found regarding the directions of these associations.Hello World reached ±4% of its target population, which is lower than the reach of its pre
Women Are Better at Selecting Gifts than Men
Monique M. H. Pollmann, Ilja van Beest
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0081643
Abstract: There is a widespread belief that women are better at selecting gifts than men; however, this claim has not been assessed on the basis of objective criteria. The current studies do exactly that and show that women do indeed make better gift selections for others, regardless of the gender of the receiver and the type of relationship between the giver and receiver. We investigate the mediating role of different aspects of interpersonal sensitivity and reveal that differences in interpersonal interest (measured with an autism questionnaire), but not differences in interpersonal reactivity, explain gender differences in gift selection quality. The current studies thus present the first objective evidence for the claim that women are better in selecting gifts for others and also give an indication of why this is the case.
Multicentric Castleman's disease and Kaposi's sarcoma in a cyclosporin treated, HIV-1 negative patient: case report
JM Bollen, AM Polstra, AC van der Kuyl, JF Weel, LA Noorduyn, MHJ van Oers, M Cornelissen
BMC Blood Disorders , 2003, DOI: 10.1186/1471-2326-3-3
Abstract: We report a HIV-1 negative, non-transplant patient who developed HHV8-associated multicentric Castleman's disease and Kaposi's sarcoma after 17 years of immunosuppressive treatment with cyclosporin A for a minimal change nephropathy. Chemotherapy with liposomal doxorubicin resolved both symptoms of multicentric Castleman's disease and Kaposi's sarcoma in this patient. A concomitant decline in the HHV8 viral load in serum/plasma, as determined by a quantitative real-time PCR assay, was observed.Multicentric Castleman's disease can be a complication of cyclosporin A treatment. Both multicentric Castleman's disease and Kaposi's sarcoma in this patient were responsive to liposomal doxorubicin, the treatment of choice for Kaposi's sarcoma at the moment, again suggesting a common mechanism linking both disorders, at least for HHV8-positive multicentric Castleman's disease and Kaposi's sarcoma.HHV8 viral load measurements can be used to monitor effectiveness of therapy.Castleman's disease, also called angiofollicular or giant lymph node hyperplasia, is a clinically heterogeneous entity that can be either localized (unicentric), or multicentric. The unicentric form, histopathologically described as the hyaline-vascular subtype, is more common, is not associated with HHV8-infection, and can mostly be treated effectively with radiotherapy or surgery as it presents as a solitary mass [1]. The multicentric form is less well understood: it is an atypical lymphoproliferative disorder of a plasma cell type, and is related to immune dysfunction. A mixture of both hyaline-vascular and plasma-cell variants can also be found [2]. Patients with MCD often develop malignancies like Kaposi's sarcoma and non-Hodgkin's lymphoma [2].Human herpesvirus 8 (HHV8, or Kaposi's sarcoma-associated herpesvirus) infection is present in nearly 100% of multicentric Castleman's disease (MCD) cases associated with HIV-1 infection, and in about 50% of cases that are HIV-1 negative [3,4]. Recently, it has b
Mechanical Cell-Matrix Feedback Explains Pairwise and Collective Endothelial Cell Behavior In Vitro
René F. M. van Oers ,Elisabeth G. Rens ,Danielle J. LaValley,Cynthia A. Reinhart-King,Roeland M. H. Merks
PLOS Computational Biology , 2014, DOI: doi/10.1371/journal.pcbi.1003774
Abstract: In vitro cultures of endothelial cells are a widely used model system of the collective behavior of endothelial cells during vasculogenesis and angiogenesis. When seeded in an extracellular matrix, endothelial cells can form blood vessel-like structures, including vascular networks and sprouts. Endothelial morphogenesis depends on a large number of chemical and mechanical factors, including the compliancy of the extracellular matrix, the available growth factors, the adhesion of cells to the extracellular matrix, cell-cell signaling, etc. Although various computational models have been proposed to explain the role of each of these biochemical and biomechanical effects, the understanding of the mechanisms underlying in vitro angiogenesis is still incomplete. Most explanations focus on predicting the whole vascular network or sprout from the underlying cell behavior, and do not check if the same model also correctly captures the intermediate scale: the pairwise cell-cell interactions or single cell responses to ECM mechanics. Here we show, using a hybrid cellular Potts and finite element computational model, that a single set of biologically plausible rules describing (a) the contractile forces that endothelial cells exert on the ECM, (b) the resulting strains in the extracellular matrix, and (c) the cellular response to the strains, suffices for reproducing the behavior of individual endothelial cells and the interactions of endothelial cell pairs in compliant matrices. With the same set of rules, the model also reproduces network formation from scattered cells, and sprouting from endothelial spheroids. Combining the present mechanical model with aspects of previously proposed mechanical and chemical models may lead to a more complete understanding of in vitro angiogenesis.
Mechanical cell-matrix feedback explains pairwise and collective endothelial cell behavior in vitro
René F. M. van Oers,Elisabeth G. Rens,Danielle J. LaValley,Cynthia Reinhart-King,Roeland M. H. Merks
Physics , 2013, DOI: 10.1371/journal.pcbi.1003774
Abstract: In vitro cultures of endothelial cells are a widely used model system of the collective behavior of endothelial cells during vasculogenesis and angiogenesis. When seeded in an extracellular matrix, endothelial cells can form blood vessel-like structures, including vascular networks and sprouts. Endothelial morphogenesis depends on a large number of chemical and mechanical factors, including the compliancy of the extracellular matrix, the available growth factors, the adhesion of cells to the extracellular matrix, cell-cell signaling, etc. Although various computational models have been proposed to explain the role of each of these biochemical and biomechanical effects, the understanding of the mechanisms underlying in vitro angiogenesis is still incomplete. Most explanations focus on predicting the whole vascular network or sprout from the underlying cell behavior, and do not check if the same model also correctly captures the intermediate scale: the pairwise cell-cell interactions or single cell responses to ECM mechanics. Here we show, using a hybrid cellular Potts and finite element computational model, that a single set of biologically plausible rules describing (a) the contractile forces that endothelial cells exert on the ECM, (b) the resulting strains in the extracellular matrix, and (c) the cellular response to the strains, suffices for reproducing the behavior of individual endothelial cells and the interactions of endothelial cell pairs in compliant matrices. With the same set of rules, the model also reproduces network formation from scattered cells, and sprouting from endothelial spheroids. Combining the present mechanical model with aspects of previously proposed mechanical and chemical models may lead to a more complete understanding of in vitro angiogenesis.
Recombinant Rhipicephalus appendiculatus gut (Ra86) and salivary gland cement (Trp64) proteins as candidate antigens for inclusion in tick vaccines: protective effects of Ra86 on infestation with adult R. appendiculatus
Saimo M, Odongo DO, Mwaura S, Vlak JM, Musoke AJ, Lubega GW, Bishop RP, van Oers MM
Vaccine: Development and Therapy , 2011, DOI: http://dx.doi.org/10.2147/VDT.S20827
Abstract: ombinant Rhipicephalus appendiculatus gut (Ra86) and salivary gland cement (Trp64) proteins as candidate antigens for inclusion in tick vaccines: protective effects of Ra86 on infestation with adult R. appendiculatus Original Research (1844) Total Article Views Authors: Saimo M, Odongo DO, Mwaura S, Vlak JM, Musoke AJ, Lubega GW, Bishop RP, van Oers MM Published Date November 2011 Volume 2011:1 Pages 15 - 23 DOI: http://dx.doi.org/10.2147/VDT.S20827 Margaret Saimo1,2,*, David O Odongo3,4,*, Stephen Mwaura3, Just M Vlak1, Anthony J Musoke5, George W Lubega2, Richard P Bishop3, Monique M van Oers1 1Laboratory of Virology, Wageningen University, Wageningen, The Netherlands; 2School of Veterinary Medicine, Makerere University, Kampala, Uganda; 3International Livestock Research Institute, Nairobi, Kenya; 4School of Biological Sciences, University of Nairobi, Nairobi, Kenya; 5Onderstepoort Veterinary Institute, Onderstepoort, Pretoria, South Africa *These two authors made an equal contribution to this work Abstract: Rhipicephalus appendiculatus gut protein Ra86 (variants Ra85A and Ra92A) and the salivary gland cement protein (Trp64) were expressed in the baculovirus-insect cell system. The recombinant gut proteins expressed as soluble proteins and the recombinant cement protein, as insoluble inclusion bodies, were used to immunize rabbits, which were then challenged with larval, nymphal, and adult stages of R. appendiculatus ticks. High tick mortality (23.3%) occurred on adult ticks that fed on rabbits vaccinated with the gut proteins, compared with 1.9% mortality in ticks that fed on unvaccinated na ve control rabbits. The mean weight of engorged female ticks was significantly reduced by 31.5% in rabbits vaccinated with the Ra86 recombinant protein compared with controls, as was egg production. Marked effects on these parameters were also observed in adult ticks as a result from vaccination using Trp64, but these were not statistically significant. For both antigens, there was no demonstrable effect on larval or nymphal ticks. This study demonstrates for the first time the protective efficacy of a homolog of Boophilus microplus Bm86 in reducing tick infestation by the adult stage of the three-host tick R. appendiculatus. The results demonstrate the potential of Ra86 for vaccine development against this tick and for the control of East Coast fever.
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