The genomes of two parasitic wasps that parasitize the diamondback moth

Abstract Background: Parasitic insects are well-known biological control agents for arthropod pests worldwide. They are capable of regulating their host’s physiology, development and behaviour. However, many of the molecular mechanisms involved in host-parasitoid interaction remain unknown. Results: We sequenced the genomes of two parasitic wasps (Cotesia vestalis, and Diadromus collaris) that parasitize the diamondback moth Plutella xylostella using Illumina and Pacbio sequencing platforms. Genome assembly using SOAPdenovo produced a 178 Mb draft genome for C. vestalis and a 399 Mb draft genome for D. collaris. A total set that contained 11,278 and 15,328 protein-coding genes for C. vestalis and D. collaris, respectively, were predicted using evidence (homology-based and transcriptome-based) and de novo prediction methodology. Phylogenetic analysis showed that the braconid C. vestalis and the ichneumonid D. collaris diverged approximately 124 million years ago. These two wasps exhibit gene gains and losses that in some cases reflect their shared life history as parasitic wasps and in other cases are unique to particular species. Gene families with functions in development, nutrient acquisition from hosts, and metabolism have expanded in each wasp species, while genes required for biosynthesis of some amino acids and steroids have been lost, since these nutrients can be directly obtained from the host. Both wasp species encode a relative higher number of neprilysins (NEPs) thus far reported in arthropod genomes while several genes encoding immune-related proteins and detoxification enzymes were lost in both wasp genomes. Conclusions: We present the annotated genome sequence of two parasitic wasps C. vestalis and D. collaris, which parasitize a common host, the diamondback moth, P. xylostella. These data will provide a fundamental source for studying the mechanism of host control and will be used in parasitoid comparative genomics to study the origin and diversification of the parasitic lifestyle

LA MODULAZIONE DEI LIVELLI DI GLUTATIONE COME STRATEGIA DI ATTACCO NELLE INTERAZIONI OSPITE-PARASSITA

Insect studies, dealing with parasitism of aphids, have shown that the disruption of host glutathione (GSH) pool and metabolisms significantly contributes to its physiological regulation and castration. The parasitic wasp Aphidius ervi injects into host aphids a venom containing large amounts of a gamma-glutamyltransferase (Ae-GGT) enzyme, which causes a depletion of GSH primarily involving ovarian tissue. Injected Ae-GGT in fact consumes substrate GSH, which ultimately triggers apoptosis. Studies on virulence factors of microrganisms have documented that the invasion strategies of selected pathogenic bacteria also target host GSH metabolism. Indeed, it has been shown that GGT activity of Helicobacter pylori and H. suis, the agents responsible of peptic ulcer, can exert antiproliferative and pro-apoptotic effects in gastric epithelial cells. By confocal microscopy, H. suis outer membrane vesicles (OMV) 12 submicroscopic structures 20-50 nm in diameter, budding from the cell surface 12 were identified as carriers of H. suis GGT, capable of delivering the enzyme to the deeper mucosal layers. In association with such membranous structures, active GGT from H. suis in fact translocates across the epithelial layers and can access lymphocytes residing in the gastric mucosa, resulting in the inhibition of lymphocyte proliferation, i.e., a perturbation of host immunity and a facilitation of bacterial infection. Cellular GSH appears, thus, to represent a conserved target for parasitic (micro)organisms which aim at altering host redox homeostasis to weaken its immune defenses, using GGT as a key-element of a virulence strategy. Taking into account the \u201cparasitic\u201d behavior exhibited by malignant cells spreading across tissues and organs of the patient (the \u201chost\u201d). GGT activity is in fact expressed in a number of malignant tumors, and expression levels often increase along with progression to more invasive phenotypes. Now, active GGT can be released from cells, including cancer cells, in association with submicroscopic vesicles resembling exosomes. The similarity of such structures with GGT-rich OMV particles of H. pylori and H. suis is indeed obvious. GGT activity of cancer cells can affect intracellular redox equilibrium, and produces in addition significant extracellular effects, e.g. on the redox status and ligand binding affinity of cell surface receptors related with cell survival/apoptosis balance. Thus, GGT-rich exosomes shed by cancer cells can produce in host\u2019s surrounding tissues effects comparable to those reported for Ae-GGT or Helicobacter GGT, possibly resulting in facilitation of malignant cells survival and diffusion

Local photo-mechanical stiffness revealed in gold nanoparticles supracrystals by ultrafast small-angle electron diffraction

We demonstrate that highly-ordered two-dimensional crystals of ligand-capped gold nanoparticles display a local photo-mechanical stiffness as high as that of solids such as graphite. In out-of equilibrium electron diffraction experiments, a strong temperature jump is induced in a thin film with a femtosecond laser pulse. The initial electronic excitation transfers energy to the underlying structural degrees of freedom, with a rate generally proportional to the stiffness of the material. With femtosecond small-angle electron diffraction, we observe the temporal evolution of the diffraction feature associated to the nearest-neighbor nanoparticle distance. The Debye-Waller decay for the octanethiol-capped nanoparticles supracrystal, in particular, is found to be unexpectedly fast, almost as fast as the stiffest solid known and observed by the same technique, i.e. graphite. Our observations unravel that local stiffness in a dense supramolecular assembly can be created by Van der Waals interactions up to a level comparable to crystalline systems characterized by covalent bonding

Symbiotic control of the olive fruit fly, Bactrocera oleae

The olive fruit fly Bactrocera oleae (Rossi) (OLF) is a major pest, which causes severe yield losses and quality decay of olive oil. The widespread use of chemical insecticides to control this pest is a major concern for the resulting environmental impact and food safety issues. Therefore, the development of sustainable control strategies is highly desirable. The primary endosymbiotic bacterium of the OLF, “Candidatus Erwinia dacicola”, is essential for successful larval development in unripe olive fruits. Then, targeting this endosymbiont with antimicrobial compounds may exert a control action against OLF. Here we evaluate the impact on OLF endosymbiont of Copper Oxychloride (CO) and the fungal metabolites Viridiol and Harzianic Acid (HA) produced by two biocontrol strains of Trichoderma spp. Laboratory bioassays were carried out on OLF wild populations to assess the effect of the oral administration of these compounds on mortality and fecundity of adult flies, and on larval development of their progeny in unripe olive fruits. Treated females were processed by qPCR to measure the endosymbiont load in the oesophageal bulb and in the midgut. Exposure to Viridiol and HA had a strong negative impact on endosymbiont load and OLF larval survival, while CO negatively affected both adults and larval stages, showing a combined toxic action and an anti-symbiotic effect, which was dose-dependent. These results provide new insights on the symbiotic control of the OLF and pave the way for developing new strategies based on the use of natural compounds with antimicrobial activity

FIRST INTERCEPTION OF TRICHOFERUS CAMPESTRIS (FALDERMANN, 1835) (COLEOPTERA CERAMBYCIDAE CERAMBYCINAE) IN ITALY

The Velvet Longhorned Beetle Trichoferus campestris (Faldermann, 1835) was intercepted for the first time in Italy, in the Naples harbour, during monitoring activities at entry points carried out in the context of the national project ASPROPI. T. campestris is widely polyphagous and able to colonize several woody species in both agricultural and forest environments. Moreover timber and solid wood items can be equally attractive to this pest. This additional report, in an area where other alien insect species had been identified in the past, emphasises how the national monitoring network represents a key element of the alert system designed to quickly counter the accidental introduction and spreading of exotic insect pests

Honeybees' physiological and behavioural immunity deficit induced by DW Viruses

Item does not contain fulltextThe purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training

A salivary chitinase of Varroa destructor influences host immunity and mite’s survival

Acknowledgments Thanks are due to Emilio Caprio and Gennaro di Prisco, University of Napoli Federico II (Italy), for their suggestions during the development of this study and for their help in maintaining the experimental apiary in Portici (Italy), to Craig R. Christie, University of Aberdeen (UK), for providing the biological material used, and to Francesco Nazzi, University of Udine (Italy), for a critical reading of an early draft of the manuscript. Funding: This work was supported by received funding from the Ministero dell’Università e della Ricerca, PRIN, project UNICO (2017954WNT, https://www.prin.miur.it) (SG, FP) and from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 613960Peer reviewedPublisher PD

Neonicotinoid Clothianidin reduces honey bee immune response and contributes to Varroa mite proliferation

The neonicotinoid Clothianidin has a negative impact on NF-\u3baB signaling and on immune responses controlled by this transcription factor, which can boost the proliferation of honey bee parasites and pathogens. This effect has been well documented for the replication of deformed wing virus (DWV) induced by Clothianidin in honey bees bearing an asymptomatic infection. Here, we conduct infestation experiments of treated bees to show that the immune-suppression exerted by Clothianidin is associated with an enhanced fertility of the parasitic mite Varroa destructor, as a possible consequence of a higher feeding efficiency. A conceptual model is proposed to describe the synergistic interactions among different stress agents acting on honey bees

Neonicotinoid Clothianidin reduces honey bee immune response and contributes to Varroa mite proliferation

The neonicotinoid Clothianidin has a negative impact on NF-κB signaling and on immune responses controlled by this transcription factor, which can boost the proliferation of honey bee parasites and pathogens. This effect has been well documented for the replication of deformed wing virus (DWV) induced by Clothianidin in honey bees bearing an asymptomatic infection. Here, we conduct infestation experiments of treated bees to show that the immune-suppression exerted by Clothianidin is associated with an enhanced fertility of the parasitic mite Varroa destructor, as a possible consequence of a higher feeding efficiency. A conceptual model is proposed to describe the synergistic interactions among different stress agents acting on honey bees