Immunocytochemical localization of phospholipase C isozymes in cord blood and adult T-lymphocytes.

The response of T-cells to peptide antigen plus major histocompatibility complex (MHC) consists of a series of cellular events collectively called T-cell activation. An essential component of this pathway is phospholipase C (PLC)gamma1, whose hydrolytic activity increases rapidly after binding of ligands to the T-cell receptor (TCR) and consequent activation of tyrosine kinases. Recent studies also suggest a GTP binding protein-dependent activation of PLCbeta during the early steps of T-cell activation. On the basis of these findings, we first checked the expression of PLC isoforms by Western blotting and by confocal and electron microscopy techniques, and then we looked for the phosphoinositide breakdown induced by CD3 engagement in cord and adult T-lymphocytes. Our results indicated that PLCbeta1 was almost exclusively expressed in cord T-cells, whereas PLCbeta2 was more strongly represented in the adult. The amount of PLCgamma1 was found to be larger in the adult than in cord cells. No significant differences were found in PLCgamma2 and delta2 expression. PLCdelta1 was scarcely detectable. On CD3 stimulation, adult lymphocytes gave rise, as expected, to a dramatic increase in phosphoinositide breakdown, whereas in cord cells this response was scarcely detected. These results indicate that a shift in PLC expression occurs in the postnatal period and that this change is associated with induction of the capability to respond to CD3 engagement with phosphoinositide hydrolysis.     

Deletion 11q23-->qter (Jacobsen syndrome). Report of three new patients.

Three unrelated patients with de novo del 11q23-->qter are reported. Clinical features included growth and mental retardation, hypotonia, trigonocephaly, facial dysmorphism with hypertelorism, epicanthal folds, abnormally shaped palpebral fissures, eye globe malformations, depressed nasal bridge, "carp-shaped" mouth, highly arched palate, low set and malformed ears. One patient had congenital heart defect, and reduced platelet count. This syndrome, originally reported by Jacobsen, is now corroborated by more than 35 patients and appears as the most common deletion involving 11q. Since deletion of subband 11q24.1 is critical for full expression of this syndrome, the JBS phenotype could be an example of contiguous gene syndrome.     

The phylogenetic structure of plant–pollinator networks increases with habitat size and isolation

Similarity among species in traits related to ecological interactions is frequently associated with common ancestry. Thus, closely related species usually interact with ecologically similar partners, which can be reinforced by diverse co‐evolutionary processes. The effect of habitat fragmentation on the phylogenetic signal in interspecific interactions and correspondence between plant and animal phylogenies is, however, unknown. Here, we address to what extent phylogenetic signal and co‐phylogenetic congruence of plant–animal interactions depend on habitat size and isolation by analysing the phylogenetic structure of 12 pollination webs from isolated Pampean hills. Phylogenetic signal in interspecific interactions differed among webs, being stronger for flower‐visiting insects than plants. Phylogenetic signal and overall co‐phylogenetic congruence increased independently with hill size and isolation. We propose that habitat fragmentation would erode the phylogenetic structure of interaction webs. A decrease in phylogenetic signal and co‐phylogenetic correspondence in plant–pollinator interactions could be associated with less reliable mutualism and erratic co‐evolutionary change.     

Interrelations between globus pallidus and hippocampal epilepsy in the cat

Electrically induced afterdischarge (ADs) were evoked in the cats' dorsal hippocampus. The action of the conditioning prestimulation of the pallidus nucleus on AD duration was studied. A significant facilitatory influence was observed when pallidal conditioning stimulation immediately preceded hippocampal test stimulation. The time course of the phenomenon showed a decrease of the conditioning action when the interval between the two stimulations increased : complete disappearance of the effect occurred after about 800 ms. Results are discussed as far as functional relationships between basal ganglia and rhinencephalic system are concerned.     

LRRC6 Mutation Causes Primary Ciliary Dyskinesia with Dynein Arm Defects

Despite recent progress in defining the ciliome, the genetic basis for many cases of primary ciliary dyskinesia (PCD) remains elusive. We evaluated five children from two unrelated, consanguineous Palestinian families who had PCD with typical clinical features, reduced nasal nitric oxide concentrations, and absent dynein arms. Linkage analyses revealed a single common homozygous region on chromosome 8 and one candidate was conserved in organisms with motile cilia. Sequencing revealed a single novel mutation in LRRC6 (Leucine-rich repeat containing protein 6) that fit the model of autosomal recessive genetic transmission, leading to a change of a highly conserved amino acid from aspartic acid to histidine (Asp146His). LRRC6 was localized to the cytoplasm and was up-regulated during ciliogenesis in human airway epithelial cells in a Foxj1-dependent fashion. Nasal epithelial cells isolated from affected individuals and shRNA-mediated silencing in human airway epithelial cells, showed reduced LRRC6 expression, absent dynein arms, and slowed cilia beat frequency. Dynein arm proteins were either absent or mislocalized to the cytoplasm in airway epithelial cells from a primary ciliary dyskinesia subject. These findings suggest that LRRC6 plays a role in dynein arm assembly or trafficking and when mutated leads to primary ciliary dyskinesia with laterality defects.     

Epitope mapping of the N‐terminal portion of tissue transglutaminase protein antigen to identify linear epitopes in celiac disease

Celiac disease (CD) is an autoimmune mediated disease with complex and multifactorial etiology. Gluten intake triggers a composite immune response involving T‐cells and B‐cells and leading to the secretion of autoantibodies if a genetic predisposition is present. Untreated CD patients show high levels of circulating autoantibodies directed to different auto‐antigens present in the intestinal mucosa. The most important auto‐antigen is the endomysial enzyme tissue transglutaminase (tTG). Both IgA and IgG antibody isotypes to tTG are known, but only the IgA antibodies demonstrate the highest disease specificity and thus are considered disease biomarkers. Because the pathogenicity and exact tTG binding properties of these autoantibodies are still unclear, the characterization of tTG antigenic domains is a crucial step in understanding CD onset and the autoimmune pathogenesis. Overlapping peptide libraries can be used for epitope mapping of selected protein portions to determine antigenic fragments contributing to the immunological activity and possibly develop innovative peptide‐based tools with high specificity and sensitivity for CD. We performed an epitope mapping study to characterize putative linear auto‐antigenic epitopes present in the tTG N‐terminal portion (1–230). A library of 23 overlapping peptides spanning tTG(1–230) was generated by Fmoc/tBu solid‐phase peptide synthesis and screened by immunoenzymatic assays employing patients' sera. The results indicate that four synthetic peptides, that is, Ac‐tTG(1–15)‐NH₂, Ac‐tTG(41–55)‐NH₂, Ac‐tTG(51–65)‐NH₂, and Ac‐tTG(151–165)‐NH₂, are recognized by IgA autoantibodies circulating in CD patients' sera. These results offer important insight on the nature of the antigen‐antibody interaction. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.