Fc receptors for IgA on human B, and human non-B, non-T lymphocytes.

Recently, receptors for IgA were demonstrated on subpopulations of human T lymphocytes. In this report, TNP-modified ox erythrocytes coated with the IgA myeloma MOPC-315 were used to detect IgA receptor-bearing lymphocytes within the human non T cell lymphocyte population. A mean of 5.3% (range 2.9 to 12.4%) of E-rosette negative human lymphocytes bound IgA-coated indicator cells. Blocking studies with soluble IgA, IgG, and IgM demonstrated that the IgA receptors on the non-T cell populations were separate and distinct from the Fc-receptors for IgG and IgM. Fractionation of the non-T lymphocytes on anti-human (Fab)2 columns into sIg+ and sIg- populations or by rosetting with EAC to provide CRL+ and CRL- populations demonstrated that Fc-IgA receptors were present on a subpopulation of sIg+, CRL+ lymphocytes, and also on sIg- (non-T, non-B) lymphocytes.     

Lectin binding to gp60 decreases specific albumin binding and transport in pulmonary artery endothelial monolayers.

The effect of albumin binding to cultured bovine pulmonary artery endothelial cell (BPAEC) monolayers on the transendothelial flux of 125I-labelled bovine serum albumin (BSA) was examined to determine its possible role on albumin transcytosis. The transport of 125I-BSA tracer across BPAEC grown on gelatin- and fibronectin-coated filters (0.8 microns pore diam.) was affected by the presence of unlabelled BSA in the medium in that transendothelial 125I-BSA permeability decreased, reaching a 40% reduction at BSA concentrations equal to or greater than 5 mg/ml. BSA binding to BPAEC monolayers was saturated at concentration of 10 mg/ml with an apparent binding affinity of 6 x 10(-7) M. In contrast, gelatin added to the medium altered neither 125I-BSA binding nor transport. Several lectins were tested for their ability to inhibit 125I-BSA binding and transport. One lectin, Ricinus communis (RCA), reduced 125I-BSA binding by 70% and transport by 40%. Other lectins, Ulex europaeus, Triticum vulgare, and Glycine max decreased neither 125I-BSA binding nor transport. The reduction of 125I-BSA transport by RCA was not observed in the presence of saturating levels of BSA, indicating that RCA influenced only the albumin-dependent component of transport. RCA, but not other lectins, precipitated a 60 kDa plasmalemmal glycoprotein from cell lysates of surface radioiodinated BPAEC monolayers. This 60 kDa glycoprotein appears to be the equivalent of gp60 identified previously as an albumin binding glycoprotein in rat microvascular endothelium. In summary, approximately 40% of albumin transport across BPAEC monolayers is dependent on albumin binding. This component of albumin transport is inhibited by 80% by the binding of RCA to gp60. These results suggest that binding of albumin to gp60 on pulmonary artery endothelial cell membrane is a critical determinant of transendothelial albumin flux involving mechanisms such as plasmalemmal vesicular transcytosis.     

The detection of Fc-IgA receptors on T and non-T,non-B acute leukemic lymphoblasts

Fc-IgA receptors have been described on purified human T-lymphocyte populations from normal individuals. More recently, non-T-cell subpopulations bearing Fc-IgA receptors have also been described. In this study, receptors for the Fc portion of IgA were detected on both T and non-T, non-B leukemic lymphoblasts from 15 patients with acute lymphoblastic leukemia (ALL). From 1.6 to 6.8% of the T lymphoblasts of 7 patients expressed Fc-IgA receptors and 0.5 to 3.9% of the non-T, non-B lymphoblasts of the remaining 8 patients expressed Fc-IgA receptors. The expression of IgA receptors on these cells may reflect the maturational state of these leukemic lymphoblasts. The detection of Fc-IgA receptors on leukemic lymphoblasts suggests that expression of these receptors on lymphoid cells represents an early maturational event.     

Tree functional traits as predictors of microburst-associated treefalls in tropical wet forests

On 19 May 2018, a microburst caused 600 isolated forest gaps in a Costa Rican tropical forest. We surveyed fallen and standing trees within gaps to determine whether certain variables are associated with treefalls. Our results highlight considerations for future research to understand the impacts of microbursts in tropical forests.     

Does developmental acclimatization reduce the susceptibility to predation in newt larvae?

Many organisms respond to the heterogeneity of abiotic environmental conditions by plastic modifications of their phenotypes (acclimation or acclimatization). Despite considerable research efforts in this area, the beneficial (adaptive) effect of acclimation or acclimatization is still debated. We examined whether the development of newt larvae (Ichthyosaura alpestris) under different natural light and thermal conditions subsequently altered their susceptibility to predation in sun‐exposed versus shaded tanks in nature. During predation trials in various light and temperature conditions, newt larvae that developed in sun‐exposed warmer tanks consistently suffered from higher predation by dragonfly nymphs (Aeshna cyanea) compared to larvae from shaded or colder tanks. We conclude that higher sun exposure during embryonic and larval development negatively affects antipredator performance even in sun‐exposed tanks: this result is inconsistent with the beneficial acclimation hypothesis. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ●● , ●●–●●.     

Mangrove root: adaptations and ecological importance

Key message

This review gives a comprehensive overview of adaptations of mangrove root system to the adverse environmental conditions and summarizes the ecological importance of mangrove root to the ecosystem.

Abstract

In plants, the first line of defense against abiotic stress is in their roots. If the soil surrounding the plant root is healthy and biologically diverse, the plant will have a higher chance to survive in stressful conditions. Different plant species have unique adaptations when exposed to a variety of abiotic stress conditions. None of the responses are identical, even though plants have become adapted to the exact same environment. Mangrove plants have developed complex morphological, anatomical, physiological, and molecular adaptations allowing survival and success in their high-stress habitat. This review briefly depicts adaptive strategies of mangrove roots with respect to anatomy, physiology, biochemistry and also the major advances recently made at the genetic and genomic levels. Results drawn from the different studies on mangrove roots have further indicated that specific patterns of gene expression might contribute to adaptive evolution of mangroves under high salinity. We also review crucial ecological contributions provided by mangrove root communities to the ecosystem including marine fauna.

     

The amino acid sequence of a Bacillus subtilis phosphoprotein that matches an orfY-tsr coding sequence

Bacillus subtilis contains a 30 kDa protein which was phosphorylated during late vegetative growth and sporulation. The sequence for the N-terminal 16 amino acids was found to be identical to the predicted sequence for the N-terminus of a small open reading frame, orfY, but diverged from the predicted sequence thereafter. The orfY region was resequenced and contained one less adenine residue than previously reported, resulting in an open reading frame from within orfY through the entire coding region for tsr which follows orfY. The predicted orfY-tsr amino acid sequence showed 24% identity to Escherichia coli fructose-1,6-bisphosphate aldolase. Two mutants in the tsr region had 2-5% of wild-type aldolase and the nucleotide sequences showed missense mutations. These results indicate that orfY-tsr encodes aldolase and should be renamed fba1.     

Optimization of α-ketoamide based p38 inhibitors through modifications to the region that binds to the allosteric site

We have optimized a novel series of potent p38 MAP kinase inhibitors based on an α-ketoamide scaffold through structure based design that due to their extended molecular architecture bind, in addition to the ATP site, to an allosteric pocket. In vitro ADME, in vivo PK and efficacy studies show these compounds to have drug-like characteristics and have resulted in the nomination of a development candidate which is currently in phase II clinical trials for the oral treatment of inflammatory conditions.