Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna)

The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga (Scenedesmus obliquus) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of colonies) in Scenedesmus at concentrations of 10–100 μl l−1 that were far below the No Observed Effect Concentration (NOEC) value of 1,000 μl l−1 for growth inhibition. The NOEC-value of FFD-6 for colony-induction was 3 μl l−1. Daphnia survival was strongly affected by FFD-6, yielding LC50–24h and LC50–48h of 148 and 26 μl l−1, respectively. In addition, clearance rates of Daphnia feeding on unicellular Scenedesmus were inhibited by FFD-6, yielding a 50% inhibition (EC50–1.5h) at 5.2 μl l−1 with a NOEC of 0.5 μl l−1. When Daphnia were offered FFD-6-induced food in which eight-celled colonies (43 × 29 μm) were most abundant, clearance rates (~0.14 ml ind.−1 h−1) were only 25% the rates of animals that were offered non-induced unicellular (15 × 5 μm) Scenedesmus (~0.56 ml ind.−1 h−1). As FFD-6 concentrations in the treated food used in the experiments were far below the NOEC for clearance rate inhibition, it is concluded that the feeding rate depression was caused by the altered morphology of the Scenedesmus moving them out of the feeding window of the daphnids. The surfactant evoked a response in Scenedesmus that is similar to the natural chemically induced defensive reaction against grazers and could disrupt the natural information conveyance between these plankton organisms

Tracking the progeny of adoptively transferred virus-specific T cells in patients posttransplant using TCR sequencing

Adoptive cellular therapies with T cells are increasingly used to treat a variety of conditions. For instance, in a recent phase 1/2 trial, we prophylactically administered multivirusspecific T-cell products to protect recipients of T-cell–depleted allogeneic stem cell grafts against viral reactivation. To establish treatment efficacy, it is important to determine the fate of the individual transferred T-cell populations. However, it is difficult to unequivocally distinguish progeny of the transferred T-cell products from recipient- or stem cell graft–derived T cells that survived T-cell depletion during conditioning or stem cell graft manipulation. Using messenger RNA sequencing of the T-cell receptor β-chains of the individual virus-specific T-cell populations within these T-cell products, we were able to track the multiple clonal virus-specific subpopulations in peripheral blood and distinguish recipient- and stem cell graft–derived virus-specific T cells from the progeny of the infused T-cell products. We observed in vivo expansion of virus-specific T cells that were exclusively derived from the T-cell products with similar kinetics as the expansion of virus-specific T cells that could also be detected before the T-cell product infusion. In addition, we demonstrated persistence of virus-specific T cells derived from the T-cell products in most patients who did not show viral reactivation. This study demonstrates that virus-specific T cells from prophylactically infused multiantigen-specific T-cell products can expand in response to antigen encounter in vivo and even persist in the absence of early viral reactivation