Influence of leaf canopy height on the occurrence of berry shrivel

Berry shrivel (BS) is a physiological disorder of grapevine that causes severe grape quality losses. The origin of BS is still unknown. In a trial with different treatments of the leaf canopy, a higher BS incidence in the plots with reduced leaf area was observed. Therefore it was investigated, whether a strong reduction of the canopy height regularly promotes BS development. Further, berry and leaf analyses should give evidence of possible changes in mineral contents which could be related to BS incidence. In three out of four trials, a strong reduction in leaf canopy height at the beginning of berry ripening, resulted in the appearance of berry shrivel (BS) symptoms. Intensive shoot topping during berry ripening therefore strongly increases the likelihood of BS occurrence, but does not always result in the appearance of BS symptoms. At the end of the berry ripening period, leaves in the reduced canopy height treatment (RCH) showed higher nitrogen content and lower potassium content than those in the normal canopy height treatment (NCH), suggesting a high and maybe also passive absorption of nitrogen, which hinders the absorption of potassium. These findings open new approaches for further studies on the causes of BS.

IL-17+ CD8+ T cell suppression by dimethyl fumarate associates with clinical response in multiple sclerosis

IL-17-producing CD8+ (Tc17) cells are enriched in active lesions of patients with multiple sclerosis (MS), suggesting a role in the pathogenesis of autoimmunity. Here we show that amelioration of MS by dimethyl fumarate (DMF), a mechanistically elusive drug, associates with suppression of Tc17 cells. DMF treatment results in reduced frequency of Tc17, contrary to Th17 cells, and in a decreased ratio of the regulators RORC-to-TBX21, along with a shift towards cytotoxic T lymphocyte gene expression signature in CD8+ T cells from MS patients. Mechanistically, DMF potentiates the PI3K-AKT-FOXO1-T-BET pathway, thereby limiting IL-17 and RORγt expression as well as STAT5-signaling in a glutathione-dependent manner. This results in chromatin remodeling at the Il17 locus. Consequently, T-BET-deficiency in mice or inhibition of PI3K-AKT, STAT5 or reactive oxygen species prevents DMF-mediated Tc17 suppression. Overall, our data disclose a DMF-AKT-T-BET driven immune modulation and suggest putative therapy targets in MS and beyond

Transcriptomic analysis of Clostridium thermocellum ATCC 27405 cellulose fermentation

<p>Abstract</p> <p>Background</p> <p>The ability of C<it>lostridium thermocellum </it>ATCC 27405 wild-type strain to hydrolyze cellulose and ferment the degradation products directly to ethanol and other metabolic byproducts makes it an attractive candidate for consolidated bioprocessing of cellulosic biomass to biofuels. In this study, whole-genome microarrays were used to investigate the expression of <it>C. thermocellum </it>mRNA during growth on crystalline cellulose in controlled replicate batch fermentations.</p> <p>Results</p> <p>A time-series analysis of gene expression revealed changes in transcript levels of ~40% of genes (~1300 out of 3198 ORFs encoded in the genome) during transition from early-exponential to late-stationary phase. K-means clustering of genes with statistically significant changes in transcript levels identified six distinct clusters of temporal expression. Broadly, genes involved in energy production, translation, glycolysis and amino acid, nucleotide and coenzyme metabolism displayed a decreasing trend in gene expression as cells entered stationary phase. In comparison, genes involved in cell structure and motility, chemotaxis, signal transduction and transcription showed an increasing trend in gene expression. Hierarchical clustering of cellulosome-related genes highlighted temporal changes in composition of this multi-enzyme complex during batch growth on crystalline cellulose, with increased expression of several genes encoding hydrolytic enzymes involved in degradation of non-cellulosic substrates in stationary phase.</p> <p>Conclusions</p> <p>Overall, the results suggest that under low substrate availability, growth slows due to decreased metabolic potential and <it>C. thermocellum </it>alters its gene expression to (i) modulate the composition of cellulosomes that are released into the environment with an increased proportion of enzymes than can efficiently degrade plant polysaccharides other than cellulose, (ii) enhance signal transduction and chemotaxis mechanisms perhaps to sense the oligosaccharide hydrolysis products, and nutrient gradients generated through the action of cell-free cellulosomes and, (iii) increase cellular motility for potentially orienting the cells' movement towards positive environmental signals leading to nutrient sources. Such a coordinated cellular strategy would increase its chances of survival in natural ecosystems where feast and famine conditions are frequently encountered.</p

Flt3L, LIF, and IL‐10 combination promotes the selective in vitro development of ESAMlow^{low} cDC2B from murine bone marrow

The development of two conventional dendritic cells (DC) subsets (cDC1 and cDC2) and the plasmacytoid DC (pDC) in vivo and in cultures of bone marrow (BM) cells is mediated by the growth factor Flt3L. However, little is known about the factors that direct the development of the individual DC subsets. Here, we describe the selective in vitro generation of murine ESAM$^{low}$ CD103$^{-}$ XCR1$^{-}$ CD172a$^{+}$ CD11b$^{+}$ cDC2 from BM by treatment with a combination of Flt3L, LIF, and IL‐10 (collectively named as FL10). FL10 promotes common dendritic cell progenitors (CDP) proliferation in the cultures, similar to Flt3L and CDP sorted and cultured in FL10 generate exclusively cDC2. These cDC2 express the transcription factors Irf4, Klf4, and Notch2, and their growth is reduced using BM from Irf4$^{-/-}$ mice, but the expression of Batf3 and Tcf4 is low. Functionally they respond to TLR3, TLR4, and TLR9 signals by upregulation of the surface maturation markers MHC II, CD80, CD86, and CD40, while they poorly secrete proinflammatory cytokines. Peptide presentation to TCR transgenic OT‐II cells induced proliferation and IFN‐γ production that was similar to GM‐CSF‐generated BM‐DC and higher than Flt3L‐generated DC. Together, our data support that FL10 culture of BM cells selectively promotes CDP‐derived ESAM$^{low}$ cDC2 (cDC2B) development and survival in vitro

Antigen receptor-mediated depletion of FOXP3 in induced regulatory T-lymphocytes via PTPN2 and FOXO1

Regulatory T-cells induced via IL-2 and TGF in vitro (iTreg) suppress immune cells and are potential therapeutics during autoimmunity. However, several reports described their re-differentiation into pathogenic cells in vivo and loss of their key functional transcription factor (TF) FOXP3 after T-cell antigen receptor (TCR)-signalling in vitro. Here, we show that TCR-activation antagonizes two necessary TFs for foxp3 gene transcription, which are themselves regulated by phosphorylation. Although the tyrosine phosphatase PTPN2 is induced to restrain IL-2-mediated phosphorylation of the TF STAT5, expression of the TF FOXO1 is downregulated and miR-182, a suppressor of FOXO1 expression, is upregulated. TGF counteracts the FOXP3-depleting TCR-signal by reassuring FOXO1 expression and by re-licensing STAT5 phosphorylation. Overexpressed phosphorylation-independent active versions of FOXO1 and STAT5 or knockdown of PTPN2 restores FOXP3 expression despite TCR-signal and absence of TGF. This study suggests novel targets for stabilisation and less dangerous application of iTreg during devastating inflammation

Transcription factor IRF4 determines germinal center formation through follicular T-helper cell differentiation

Follicular T-helper (TFH) cells cooperate with GL7+CD95+ germinal center (GC) B cells to induce antibody maturation. Herein, we identify the transcription factor IRF4 as a T-cell intrinsic precondition for TFH cell differentiation and GC formation. After immunization with protein or infection with the protozoon Leishmania major, draining lymph nodes (LNs) of IFN-regulatory factor-4 (Irf4−/−) mice lacked GCs and GC B cells despite developing normal initial hyperplasia. GCs were also absent in Peyer’s patches of naive Irf4−/− mice. Accordingly, CD4+ T cells within the LNs and Peyer’s patches failed to express the TFH key transcription factor B-cell lymphoma-6 and other TFH-related molecules. During chronic leishmaniasis, the draining Irf4−/− LNs disappeared because of massive cell death. Adoptive transfer of WT CD4+ T cells or few L. major primed WT TFH cells reconstituted GC formation, GC B-cell differentiation, and LN cell survival. In support of a T-cell intrinsic IRF4 activity, Irf4−/− TFH cell differentiation was not rescued by close neighborhood to transferred WT TFH cells. Together with its known B lineage-specific roles during plasma cell maturation and class switch, our study places IRF4 in the center of antibody production toward T-cell–dependent antigens