Standard State Fugacity Coefficients for the Hypothetical Vapor by Bridging from the Real Gas Fugacity Coefficients Through the Gibbs-duhem Equation

Chemical Engineerin

The Effect of Antigen Stimulation on the Migration of Mature T Cells from the Peripheral Lymphoid Tissues to the Thymus

Although the maturation and export of T cells from the thymus has been extensively studied, the movement of cells in the opposite direction has been less well documented. In particular, the question of whether T cells which have been activated by antigen in the periphery are more likely to return to the thymus had been raised but not clearly answered. We examined this issue by activating T cells present in the periphery with their cognate antigen, and assessing migration to the thymus. TCR-transgenic cells from OT-I mice (Thy1.2+), which recognise the ovalbumin peptide OVA257–264 in the context of H-2Kb, were transferred into otherwise unmanipulated Thy1.1+ C57BL/6 mice. Recipient mice were injected i.v. with 5 μg peptide (SIINFEKL) approximately 24 hours later. The numbers of donor-derived (Thy1.2+) cells in the thymus and peripheral lymphoid tissue were determined. The results clearly show increased numbers of transgenic cells in the thymus 3 days after antigenic stimulation. However, since numbers of transgenic cells increased in the spleen and LN in about the same proportion, the data do not support the notion that there is highly increased selective migration of activated T cells to the thymus. Rather, they suggest that a sample of peripheral cells enters the thymus each day, and that the mature immigrants detected in the thymus merely reflect the contents of the peripheral T cell pool

Grand County Agriculture Profile

This publication includes a report that gives agricultural facts and statistics pertaining to Grand County

Sanpete County Agriculture Profile

This publication includes a report that gives agricultural facts and statistics pertaining to Sanpete County

San Juan County Agriculture Profile

This publication includes a report that gives agricultural facts and statistics pertaining to San Juan County

Chewing the fat on natural killer T cell development

Natural killer T cells (NKT cells) are selected in the thymus by self-glycolipid antigens presented by CD1d molecules. It is currently thought that one specific component of the lysosomal processing pathway, which leads to the production of isoglobotrihexosylceramide (iGb3), is essential for normal NKT cell development. New evidence now shows that NKT cell development can be disrupted by a diverse range of mutations that interfere with different elements of the lysosomal processing and degradation of glycolipids. This suggests that lysosomal storage diseases (LSDs) in general, rather than one specific defect, can disrupt CD1d antigen presentation, leading to impaired development of NKT cells

Differential Requirement for the CD45 Splicing Regulator hnRNPLL for Accumulation of NKT and Conventional T Cells

Natural killer T (NKT) cells represent an important regulatory T cell subset that develops in the thymus and contains immature (NK1.1lo) and mature (NK1.1hi) cell subsets. Here we show in mice that an inherited mutation in heterogeneous ribonucleoprotein L-like protein (hnRNPLLthunder), that shortens the survival of conventional T cells, has no discernible effect on NKT cell development, homeostasis or effector function. Thus, Hnrpll deficiency effectively increases the NKT∶T cell ratio in the periphery. However, Hnrpll mutation disrupts CD45RA, RB and RC exon silencing of the Ptprc mRNA in both NKT and conventional T cells, and leads to a comparably dramatic shift to high molecular weight CD45 isoforms. In addition, Hnrpll mutation has a cell intrinsic effect on the expression of the developmentally regulated cell surface marker NK1.1 on NKT cells in the thymus and periphery but does not affect cell numbers. Therefore our results highlight both overlapping and divergent roles for hnRNPLL between conventional T cells and NKT cells. In both cell subsets it is required as a trans-acting factor to regulate alternative splicing of the Ptprc mRNA, but it is only required for survival of conventional T cells

Powdery mildew fungal effector candidates share N-terminal Y/F/WxC-motif

Extent: 13p.Background: Powdery mildew and rust fungi are widespread, serious pathogens that depend on developing haustoria in the living plant cells. Haustoria are separated from the host cytoplasm by a plant cell-derived extrahaustorial membrane. They secrete effector proteins, some of which are subsequently transferred across this membrane to the plant cell to suppress defense. Results: In a cDNA library from barley epidermis containing powdery mildew haustoria, two-thirds of the sequenced ESTs were fungal and represented ~3,000 genes. Many of the most highly expressed genes encoded small proteins with N-terminal signal peptides. While these proteins are novel and poorly related, they do share a three-amino acid motif, which we named "Y/F/WxC", in the N-terminal of the mature proteins. The first amino acid of this motif is aromatic: tyrosine, phenylalanine or tryptophan, and the last is always cysteine. In total, we identified 107 such proteins, for which the ESTs represent 19% of the fungal clones in our library, suggesting fundamental roles in haustoria function. While overall sequence similarity between the powdery mildew Y/F/WxC-proteins is low, they do have a highly similar exon-intron structure, suggesting they have a common origin. Interestingly, searches of public fungal genome and EST databases revealed that haustoria-producing rust fungi also encode large numbers of novel, short proteins with signal peptides and the Y/F/WxC-motif. No significant numbers of such proteins were identified from genome and EST sequences from either fungi which do not produce haustoria or from haustoria-producing Oomycetes. Conclusion: In total, we identified 107, 178 and 57 such Y/F/WxC-proteins from the barley powdery mildew, the wheat stem rust and the wheat leaf rust fungi, respectively. All together, our findings suggest the Y/F/WxC-proteins to be a new class of effectors from haustoria-producing pathogenic fungi.Dale Godfrey, Henrik Böhlenius, Carsten Pedersen, Ziguo Zhang, Jeppe Emmersen and Hans Thordal-Christense