Protein Tyrosine Phosphatase-Induced Hyperactivity Is a Conserved Strategy of a Subset of BaculoViruses to Manipulate Lepidopteran Host Behavior

This is the final version. Available from PLoS via the DOI in this record.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. © 2012 van Houte et al.Program Strategic Alliances of the Royal Dutch Academy of SciencesMEERVOUD grant from the Netherlands Organization for Scientific ResearchC.T. de Wit Graduate School for Production Ecology and Resource Conservatio

Protein Tyrosine Phosphatase-Induced Hyperactivity Is a Conserved Strategy of a Subset of BaculoViruses to Manipulate Lepidopteran Host Behavior

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

An in vitro approach to study effects of prebiotics and probiotics on the faecal microbiota and selected immune parameters relevant to the elderly

The aging process leads to alterations of gut microbiota and modifications to the immune response, such changes may be associated with increased disease risk. Prebiotics and probiotics can modulate microbiome changes induced by aging; however, their effects have not been directly compared. The aim of this study was to use anaerobic batch culture fermenters to assess the impact of various fermentable carbohydrates and microorganisms on the gut microbiota and selected immune markers. Elderly volunteers were used as donors for these experiments to enable relevance to an aging population. The impact of fermentation supernatants on immune markers relevant to the elderly were assessed in vitro. Levels of IL-1β, IL-6, IL-8, IL-10 and TNF-α in peripheral blood mononuclear cell culture supernatants were measured using flow cytometry. Trans-galactooligosaccharides (B-GOS) and inulin both stimulated bifidobacteria compared to other treatments (p<0.05). Fermentation supernatants taken from faecal batch cultures supplemented with B-GOS, inulin, B. bifidum, L. acidophilus and Ba. coagulans inhibited LPS induced TNF-α (p<0.05). IL-10 production, induced by LPS, was enhanced by fermentation supernatants from faecal batch cultures supplemented with B-GOS, inulin, B. bifidum, L. acidophilus, Ba. coagulans and Bac. thetaiotaomicron (p<0.05). To conclude, prebiotics and probiotics could lead to potentially beneficial effects to host health by targeting specific bacterial groups, increasing saccharolytic fermentation and decreasing inflammation associated with aging. Compared to probiotics, prebiotics led to greater microbiota modulation at the genus level within the fermenters

Iron addition as a measure to restore water quality: Implications for macrophyte growth

Eutrophication of shallow lakes in North-West Europe has resulted in cyanobacterial blooms, turbid water, and a decline in submerged macrophytes. Even though external inputs of phosphorus (P) are declining, internal loading of P from the sediment may delay the recovery of these aquatic ecosystems. Iron can be a useful chemical binding agent to combat internal P loading in shallow lakes, but may potentially be harmful for macrophyte growth. We tested whether iron addition as a restoration measure harms the growth of submerged macrophytes. We hypothesized that this depends on the iron dosage and the rooting strategy of the macrophytes. We experimentally tested the effects of Fe (FeCl3) on the submerged macrophytes Potamogeton pectinatus L and Elodea nuttallii (Planch.) H. St. John. Iron was dosed at a concentration of 20 g Fe m(-2) and 40 g Fe m(-2) to the surface water or to both the surface water and sediment. E. nuttallii growth was not affected by iron addition, whereas P. pectinatus growth significantly decreased with increasing iron concentrations. Nonetheless, biomass of both species increased in all treatments relative to starting conditions. During the experiment, propagules sprouted from a propagule bank in the sediment including species with a high conservation value and this spontaneous emergence was not influenced by increasing iron concentrations. We conclude that adding iron(III)chloride in dosages of 20-40 g m(-2) may reduce growth of some macrophyte species, but does not prevent overall macrophyte recovery. It may however affect macrophyte community composition due to differential responses of macrophyte species to iron addition. (C) 2014 Elsevier B.V. All rights reserved