Use of RNAi to develop new biotechnologies for insect control

The identification of new bioinsecticides and of their efficient delivery strategies is one of the current approaches to reduce the use of synthetic chemicals in agriculture. The use of natural antagonists as a source of virulence factors or of molecular technologies that mimic their negative effect on the host insects paves the way toward the development of new bioinspired tools of pest control. To this aim, RNA interference (RNAi) can be used to artificially down-regulate host genes negatively targeted by virulence factors of natural antagonists, providing new opportunities for pest control. Recently, it has been demonstrated that RNAi-mediated silencing of an immune gene (Sl 102), to reproduce the negative effect of a polydnavirus associated with a parasitic wasp, generates an immunosuppressed phenotype in Spodoptera littoralis (Lepidoptera: Noctuidae) larvae, making them more susceptible to the entomopathogen Bacillus thuringiensis. To exploit this novel pest control tool, it is essential to limit the environmental and insect gut degradation of double strand RNA (dsRNA) molecules. Here we contribute to this research goal by developing two delivery strategies, based on the expression of dsRNA molecules in Escherichia coli and transgenic tobacco plants. Experimental larvae ingesting bacteria or plant tissue expressing Sl 102 dsRNA showed marked transcriptional down-regulation of the targeted gene and both enhanced the killing activity of a Bt-based biopesticide (Xentari™), demonstrating that these two delivery strategies were both effective. Moreover, to further enhance the immunosuppression and the resulting biocontrol level by Bt, we concurrently silenced an additional immune gene (Sl gasmin), which encodes a protein acting as an opsonizing factor promoting phagocytosis. The double silencing was successfully observed and was associated with a significant impairment of both encapsulation/nodulation and phagocytosis. However, this double immune deficiency did not induce a synergistic response, further enhancing the killing activity by Bt, which, indeed, was similar to that observed when only Sl 102 gene was silenced. In conclusion, bacteria and transgenic plants expressing Sl 102 dsRNA appear to be two promising delivery strategies for field application. Their use to induce immunosuppression offers the possibility to pursue a new bio-inspired strategy to suppress pests based on the enhancement of their sensitivity to natural antagonists and, thus, reinforcing the important ecosystem service they provide

An evolutionary game model for behavioral gambit of loyalists: Global awareness and risk-aversion

We study the phase diagram of a minority game where three classes of agents are present. Two types of agents play a risk-loving game that we model by the standard Snowdrift Game. The behaviour of the third type of agents is coded by {\em indifference} w.r.t. the game at all: their dynamics is designed to account for risk-aversion as an innovative behavioral gambit. From this point of view, the choice of this solitary strategy is enhanced when innovation starts, while is depressed when it becomes the majority option. This implies that the payoff matrix of the game becomes dependent on the global awareness of the agents measured by the relevance of the population of the indifferent players. The resulting dynamics is non-trivial with different kinds of phase transition depending on a few model parameters. The phase diagram is studied on regular as well as complex networks

Enhancement of Bacillus thuringiensis toxicity by feeding Spodoptera littoralis larvae with bacteria expressing immune suppressive dsRNA

RNAi interference (RNAi) for insect pest control is often used to silence genes controlling vital functions, thus generating lethal phenotypes. Here, we propose a novel approach, based on the knockout of an immune gene by dsRNA-expressing bacteria as a strategy to enhance the impact of spray applications of the entomopathogen Bacillus thuringiensis ( Bt). The target gene, Sl 102, controls the encapsulation and nodulation responses in the noctuid moth Spodoptera littoralis (Lepidop- tera, Noctuidae). To deliver Sl 102 dsRNA, we have developed a bacterial expression system, using HT115 Escherichia coli. This allows a much cheaper production of dsRNA and its protection against degradation. Transformed bacteria (dsRNA- Bac) administered through artificial diet proved to be more effective than dsRNA synthesized in vitro, both in terms of gene silencing and immunosuppression. This is a likely consequence of reduced dsRNA environmental degradation and of its protected release in the harsh conditions of the gut. The combined oral administration with artificial diet of dsRNA-Bac and of a Bt-based biopesticide (Xentari™) resulted in a remarkable enhancement of Bt killing activity, both on 4th and 5th instar larvae of S. littoralis, either when the two components were simultaneously administered or when gene silencing was obtained before Bt exposure. These results pave the way toward the development of novel Bt spray formulations containing killed dsRNA-Bac, which synergize Bt toxins by suppressing the insect immune response. This strategy will preserve the long-term efficacy of Bt-based products and can, in principle, enhance the ecological services provided by insect natural antagonists

Evaluation of the Properties of Iron Oxide-Filled Castor Oil Polyurethane

The aim of this study was to obtain and evaluate the electrical, thermal and mechanical properties of iron oxide-filled castor oil polyurethane (PU/Fe2O3). The iron oxide used in this study was a residue derived from the steel pickling process of a Brazilian steel rolling industry. Polymeric composites with different iron oxide volume fractions (2.5, 5.0, 7.5, 10.0 and 12.5%) were prepared through the casting process followed by compression molding at room temperature. The composites were analyzed by FTIR, XRD and densities, tensile strength, Young’s modulus, electrical and thermal conductivities measurements. By increasing the iron oxide content, the apparent density, tensile strength, Young’s modulus and electrical conductivity values of the composites were also increased. The iron oxide additions did not change significantly the value of thermal conductivity (from 0.191 W.mK–1 for PU up to 0.340 W.mK–1 for PU enriched with 12.5% v/v of iron oxide). Thus, even at the higher iron oxide concentration, the compounds as well as the pure polyurethane can be classified as thermal insulators

MRI pattern characterization of cerebral cardioembolic lesions following atrial fibrillation ablation

BackgroundRecognizing etiology is essential for treatment and secondary prevention of cerebral ischemic events. A magnetic resonance imaging (MRI) pattern suggestive of an embolic etiology has been described but, to date, there are no uniformly accepted criteria.AimThe purpose of the study is to describe MRI features of ischemic cerebral lesions occurring after transcatheter ablation of atrial fibrillation (AF).MethodsA systematic review and meta-analysis of studies performing brain imaging investigations before and after AF transcatheter ablation was performed. The incidence of cerebral ischemic lesions after AF transcatheter ablation was the primary endpoint. The co-primary endpoints were the prevalence of the different neuroimaging features regarding the embolic cerebral ischemic lesions.ResultsA total of 25 studies, encompassing 3,304 patients, were included in the final analysis. The incidence of ischemic cerebral lesions following AF transcatheter ablation was 17.2% [95% confidence interval (CI) 12.2%–23.8%], of which a minimal fraction was symptomatic [0.60% (95% CI 0.09%–3.9%)]. Only 1.6% of the lesions (95% CI 0.9%–3.0%) had a diameter >10 mm, and in 20.5% of the cases the lesions were multiple (95% CI 17.1%–24.4%). Brain lesions were equally distributed across the two hemispheres and the different lobes; cortical location was more frequent [64.0% (95% CI 42.9%–80.8%)] while the middle cerebral artery territory was the most involved 37.0% (95% CI 27.3–48.0).ConclusionsThe prevailing MRI pattern comprises a predominance of small (<10 mm) cortical lesions, more prevalent in the territory of the middle cerebral artery

Stress-induced lncRNA LASTR fosters cancer cell fitness by regulating the activity of the U4/U6 recycling factor SART3

Dysregulated splicing is a common event in cancer even in the absence of mutations in the core splicing machinery. The aberrant long non-coding transcriptome constitutes an uncharacterized level of regulation of post-transcriptional events in cancer. Here, we found that the stress-induced long non-coding RNA (lncRNA), LINCO2657 or LASTR (lncRNA associated with SART3 regulation of splicing), is upregulated in hypoxic breast cancer and is essential for the growth of LASTR-positive triple-negative breast tumors. LASTR is upregulated in several types of epithelial cancers due to the activation of the stress-induced JNK/c-JUN pathway. Using a mass-spectrometry based approach, we identified the RNA-splicing factor SART3 as a LASTR-interacting partner. We found that LASTR promotes splicing efficiency by controlling SART3 association with the U4 and U6 small nuclear ribonucleoproteins (snRNP) during spliceosome recycling. Intron retention induced by LASTR depletion downregulates expression of essential genes, ultimately decreasing the fitness of cancer cells

A soil fungus confers plant resistance against a phytophagous insect by disrupting the symbiotic role of its gut microbiota

Plants generate energy flows through natural food webs, driven by competition for resources among organisms, which are part of a complex network of multitrophic interactions. Here, we demonstrate that the interaction between tomato plants and a phytophagous insect is driven by a hidden interplay between their respective microbiotas. Tomato plants colonized by the soil fungus Trichoderma afroharzianum, a beneficial microorganism widely used in agriculture as a biocontrol agent, negatively affects the development and survival of the lepidopteran pest Spodoptera littoralis by altering the larval gut microbiota and its nutritional support to the host. Indeed, experiments aimed to restore the functional microbial community in the gut allow a complete rescue. Our results shed light on a novel role played by a soil microorganism in the modulation of plant-insect interaction, setting the stage for a more comprehensive analysis of the impact that biocontrol agents may have on ecological sustainability of agricultural systems

Integrator restrains paraspeckles assembly by promoting isoform switching of the lncRNA NEAT1

RNA 3' end processing provides a source of transcriptome diversification which affects various (patho)-physiological processes. A prime example is the transcript isoform switch that leads to the read-through expression of the long non-coding RNA NEAT1_2, at the expense of the shorter polyadenylated transcript NEAT1_1. NEAT1_2 is required for assembly of paraspeckles (PS), nuclear bodies that protect cancer cells from oncogene-induced replication stress and chemotherapy. Searching for proteins that modulate this event, we identified factors involved in the 3' end processing of polyadenylated RNA and components of the Integrator complex. Perturbation experiments established that, by promoting the cleavage of NEAT1_2, Integrator forces NEAT1_2 to NEAT1_1 isoform switching and, thereby, restrains PS assembly. Consistently, low levels of Integrator subunits correlated with poorer prognosis of cancer patients exposed to chemotherapeutics. Our study establishes that Integrator regulates PS biogenesis and a link between Integrator, cancer biology, and chemosensitivity, which may be exploited therapeutically

Exploring the origin of retail stores in Europe: evidence from Southern Italy from the 6th century BCE to the 3rd century BCE

Retail literature reports considerable research on the role that technology has played in retailing as an enabler of change, with emphasis on the shifting of power from retailers to consumers. While scholarly attention has been paid mainly to investigating the current scenario in order to predict future trends and preview retail settings for the coming years, the origins of the retail process, in terms of physical space for selling activities and history of retailing as discipline of business history, is less investigated. Using qualitative data gathered through historical documents and archaeological findings, the present study goes back beyond modern retail settings to explore the origins of points of sales as early as the Magna Graecia period (600 BCE – 300 BCE). Such historical analysis not only offers an insight into the origin of the modern retailing, but also cast broader questions about the degree to which historical interpretations of the growth of retailing have been evolved, by emphasising that after 2000 years, there are still similarities. To the authors’ knowledge, this current study is the first to extend the baseline for such an understanding back a further millennium or so