The Neotropical mirid predator Macrolophus basicornis uses volatile cues to avoid contacting old, Trichogramma pretiosum parasitized eggs of Tuta absoluta

Polyphagous mirid predators are increasingly used in commercial, augmentative biological control. Information about their foraging behaviour is essential, especially if one intends to use several natural enemies to control one or more pests in a crop, to detect if negative intraguild effects occur. We studied a case of intraguild predation (IGP) involving the predator Macrolophus basicornis (Stal) (Hemiptera Miridae) of the worldwide invasive South American tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera Gelechiidae) and explored how this predator deals with prey parasitized by Trichogramma pretiosum (Riley) (Hymenoptera Trichogrammatidae). Behavioural observations show that M. basicornis predators contacted significantly fewer old, parasitized eggs of T. absoluta than recently parasitized eggs. Olfactometer tests revealed that predators could smell differences between vola-tiles of tomato leaves infested with eggs of different qualities to locate suitable prey. They preferred volatiles from leaflets with unparasitized eggs above control leaflets and, moreover, preferred volatiles from leaflets with recently parasitized eggs over volatiles of leaflets with 5-day-old parasitized eggs. When predators and parasitoids are used together to control T. absoluta, parasitoids should be introduced one week before predators are released to prevent high levels of IGP

Intensity of intraguild predation of parasitized eggs by mirid predators depends on time since parasitization: a case study with the parasitoid Trichogramma pretiosum and the predator Macrolophus basicornis attacking Tuta absoluta eggs

Concurrent releases of several species of natural enemies for pest control have been studied in various crops with either positive, neutral, or negative results. To control the pest Tuta absoluta (Meyrick) (Lepidoptera Gelechiidae), only the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera Trichogrammatidae) is applied on many hectares with tomatoes in South America. Use of the mirid predator Macrolophus basicornis Stal (Hemiptera Miridae) is considered either alone or in combination with the parasitoid T. pretiosum. To determine if intraguild relationships between the two natural enemies negatively affect concurrent releases, unparasitized eggs and eggs parasitized by T. pretiosum were exposed to the predator. Knowing which stages of parasitized eggs are consumed or rejected by the predator is important for development of a release strategy resulting in highest pest mortality. M. basicornis consumed 1-2 day old parasitized eggs as well as unparasitized eggs, and, consequently, expressed strong intraguild predation (IGP). Five and 9-day old parasitized eggs were often not consumed, and, therefore, exerted the phenomenon of competitive exclusion (CE). Predation rates of old parasitized eggs were very low and similar in no-choice and choice tests, and in experiments with a large (100), medium (50) and very limited (10) number of preys offered, demonstrating a strong CE effect. Interestingly, in choice experiments with unparasitized and old parasitized eggs, predators started to consume unparasitized eggs significantly later than when only unparasitized or young parasitized eggs were offered. This suggests that old, parasitized eggs in some way reduce the foraging activity of M. basicornis. We expect that stronger pest reduction by concurrent releases of both natural enemies will only occur at the start of the tomato production season and when the egg parasitoid is introduced seven days before the mirid predator in order to reduce intraguild predation of parasitized eggs by the predator

Enforced expression of MLL-AF4 fusion in cord blood CD34+ cells enhances the hematopoietic repopulating cell function and clonogenic potential but is not sufficient to initiate leukemia

AbstractInfant acute lymphoblastic leukemia harboring the fusion mixed-lineage leukemia (MLL)-AF4 is associated with a dismal prognosis and very brief latency. Our limited understanding of transformation by MLL-AF4 is reflected in murine models, which do not accurately recapitulate the human disease. Human models for MLL-AF4 disease do not exist. Hematopoietic stem or progenitor cells (HSPCs) represent probable targets for transformation. Here, we explored in vitro and in vivo the impact of the enforced expression of MLL-AF4 in human cord blood-derived CD34+ HSPCs. Intrabone marrow transplantation into NOD/SCID-IL2Rγ−/− mice revealed an enhanced multilineage hematopoietic engraftment, efficiency, and homing to other hematopoietic sites on enforced expression of MLL-AF4. Lentiviral transduction of MLL-AF4 into CD34+ HSPCs increased the in vitro clonogenic potential of CD34+ progenitors and promoted their proliferation. Consequently, cell cycle and apoptosis analyses suggest that MLL-AF4 conveys a selective proliferation coupled to a survival advantage, which correlates with changes in the expression of genes involved in apoptosis, sensing DNA damage and DNA repair. However, MLL-AF4 expression was insufficient to initiate leukemogenesis on its own, indicating that either additional hits (or reciprocal AF4-MLL product) may be required to initiate ALL or that cord blood-derived CD34+ HSPCs are not the appropriate cellular target for MLL-AF4-mediated ALL

Residual Expression of the Reprogramming Factors Prevents Differentiation of iPSC Generated from Human Fibroblasts and Cord Blood CD34+ Progenitors

Human induced pluripotent stem cells (hiPSC) have been generated from different tissues, with the age of the donor, tissue source and specific cell type influencing the reprogramming process. Reprogramming hematopoietic progenitors to hiPSC may provide a very useful cellular system for modelling blood diseases. We report the generation and complete characterization of hiPSCs from human neonatal fibroblasts and cord blood (CB)-derived CD34+ hematopoietic progenitors using a single polycistronic lentiviral vector containing an excisable cassette encoding the four reprogramming factors Oct4, Klf4, Sox2 and c-myc (OKSM). The ectopic expression of OKSM was fully silenced upon reprogramming in some hiPSC clones and was not reactivated upon differentiation, whereas other hiPSC clones failed to silence the transgene expression, independently of the cell type/tissue origin. When hiPSC were induced to differentiate towards hematopoietic and neural lineages those hiPSC which had silenced OKSM ectopic expression displayed good hematopoietic and early neuroectoderm differentiation potential. In contrast, those hiPSC which failed to switch off OKSM expression were unable to differentiate towards either lineage, suggesting that the residual expression of the reprogramming factors functions as a developmental brake impairing hiPSC differentiation. Successful adenovirus-based Cre-mediated excision of the provirus OKSM cassette in CB-derived CD34+ hiPSC with residual transgene expression resulted in transgene-free hiPSC clones with significantly improved differentiation capacity. Overall, our findings confirm that residual expression of reprogramming factors impairs hiPSC differentiation

Coffee, tea and decaffeinated coffee in relation to hepatocellular carcinoma in a European population: multicentre, prospective cohort study

Inverse associations of coffee and/or tea in relation to hepatocellular carcinoma (HCC) risk have been consistently identified in studies conducted mostly in Asia where consumption patterns of such beverages differ from Europe. In the European Prospective Investigation into Cancer and nutrition (EPIC), we identified 201 HCC cases among 486,799 men/women, after a median follow-up of 11 years. We calculated adjusted hazard ratios (HR) for HCC incidence in relation to quintiles/categories of coffee/tea intakes. We found that increased coffee and tea intakes were consistently associated with lower HCC risk. The inverse associations were substantial, monotonic and statistically significant. Coffee consumers in the highest compared to the lowest quintile had lower HCC risk by 72% (HR: 0.28; 95% confidence intervals (CI): 0.16 to 0.50, P-trend <0.001). The corresponding association of tea with HCC risk was 0.41 (95% CI: 0.22 to 0.78, P-trend=0.003). There was no compelling evidence of heterogeneity of these associations across strata of important HCC risk factors, including hepatitis B or hepatitis C status (available in a nested case-control study). The inverse, monotonic associations of coffee intake with HCC were apparent for caffeinated (P-trend=0.009), but not decaffeinated (P-trend=0.45) coffee for which, however, data were available for a fraction of subjects. Results from this multi-centre, European cohort study strengthen the existing evidence regarding the inverse association between coffee/tea and HCC risk. Given the apparent lack of heterogeneity of these associations by HCC risk factors and that coffee/tea are universal exposures, our results could have important implications for high HCC risk subjects