Biomass and morphology of fine roots in temperate broad-leaved forests differing in tree species diversity: is there evidence of below-ground overyielding?

Biodiversity effects on ecosystem functioning in forests have only recently attracted increasing attention. The vast majority of studies in forests have focused on above-ground responses to differences in tree species diversity, while systematic analyses of the effects of biodiversity on root systems are virtually non-existent. By investigating the fine root systems in 12 temperate deciduous forest stands in Central Europe, we tested the hypotheses that (1) stand fine root biomass increases with tree diversity, and (2) ‘below-ground overyielding’ of species-rich stands in terms of fine root biomass is the consequence of spatial niche segregation of the roots of different species. The selected stands represent a gradient in tree species diversity on similar bedrock from almost pure beech forests to medium-diverse forests built by beech, ash, and lime, and highly-diverse stands dominated by beech, ash, lime, maple, and hornbeam. We investigated fine root biomass and necromass at 24 profiles per stand and analyzed species differences in fine root morphology by microscopic analysis. Fine root biomass ranged from 440 to 480 g m−2 in the species-poor to species-rich stands, with 63–77% being concentrated in the upper 20 cm of the soil. In contradiction to our two hypotheses, the differences in tree species diversity affected neither stand fine root biomass nor vertical root distribution patterns. Fine root morphology showed marked distinctions between species, but these root morphological differences did not lead to significant differences in fine root surface area or root tip number on a stand area basis. Moreover, differences in species composition of the stands did not alter fine root morphology of the species. We conclude that ‘below-ground overyielding’ in terms of fine root biomass does not occur in the species-rich stands, which is most likely caused by the absence of significant spatial segregation of the root systems of these late-successional species

Comparison of outcome after pediatric liver transplantation for metabolic diseases and biliary atresia

Metabolic diseases (MD) are the second largest indication group for orthotopic liver transplantation (OLTx) in children after biliary atresia (BA). A better outcome after transplantation can be expected because of a better pretransplant condition and the absence of previous abdominal surgery. To prove this statement, patient survival, graft survival, and morbidity were compared between a group of 24 for MD and 52 for BA consecutively transplanted children. The actuarial one- and five-year patient survival rates for MD were 96% and 84%, and for BA 84% and 70%, respectively (p logrank test = 0.17). Three MD children (13%) and 15 BA children (29%) died. The actuarial one- and five-year graft survival rates for MD were 75% and 58%, and for BA 75% and 64%, respectively (p logrank test = 0.76). Seven MD children (29%) and 11 BA children (21%) were retransplanted. Postoperative bleeding and gastrointestinal complications occurred less frequent (4% vs. 18% and 4% vs. 14%, respectively), whereas biliary complications, viral infections, and acute rejection occurred more frequently (38% vs. 21%, 29% vs. 15%, and 50% vs. 37%, respectively) in MD children. The difference in the incidence of the various postoperative complications between both groups was not statistically significant. The mean ICU and ventilator stay was 7.5 and four days, respectively, in MD children and 16 and 10 days, respectively, in BA children (p = ns). The mean infection, complication, intervention, and retransplantation rate was equal in both groups. Conclusion: Mortality and morbidity after pediatric liver transplantation for MD and BA are not different despite the better starting point for children with MD

Steroid-resistant human inflammatory ILC2s are marked by CD45RO and elevated in type 2 respiratory diseases

Group 2 innate lymphoid cells (ILC2s) orchestrate protective type 2 immunity and have been implicated in various immune disorders. In the mouse, circulatory inflammatory ILC2s (iILC2s) were identified as a major source of type 2 cytokines. The human equivalent of the iILC2 subset remains unknown. Here, we identify a human inflammatory ILC2 population that resides in inflamed mucosal tissue and is specifically marked by surface CD45RO expression. CD45RO+ ILC2s are derived from resting CD45RA+ ILC2s upon activation by epithelial alarmins such as IL-33 and TSLP, which is tightly linked to STAT5 activation and up-regulation of the IRF4/BATF transcription factors. Transcriptome analysis reveals marked similarities between human CD45RO+ ILC2s and mouse iILC2s. Frequencies of CD45RO+ inflammatory ILC2 are increased in inflamed mucosal tissue and in the circulation of patients with chronic rhinosinusitis or asthma, correlating with disease severity and resistance to corticosteroid therapy. CD45RA-to-CD45RO ILC2 conversion is suppressed by corticosteroids via induction of differentiation toward an immunomodulatory ILC2 phenotype characterized by low type 2 cytokine and high amphiregulin expression. Once converted, however, CD45RO+ ILC2s are resistant to corticosteroids, which is associated with metabolic reprogramming resulting in the activation of detoxification pathways. Our combined data identify CD45RO+ inflammatory ILC2s as a human analog of mouse iILC2s linked to severe type 2 inflammatory disease and therapy resistance