MUC4 involvement in ErbB2/ErbB3 phosphorylation and signaling in response to airway cell mechanical injury

The receptor tyrosine kinases ErbB2 and ErbB3 are phosphorylated in response to injury of the airway epithelium. Since we have shown that the membrane mucin MUC4 can act as a ligand/modulator for ErbB2, affecting its localization in polarized epithelial cells and its phosphorylation, we questioned whether Muc4 was involved, along with ErbB2 and ErbB3, in the damage response of airway epithelia. To test this hypothesis, we first examined the localization of MUC4 in human airway samples. Both immunocytochemistry and immunofluorescence showed a co‐localization of MUC4 and ErbB2 at the airway luminal surface. Sequential immunoprecipitation and immunoblotting from airway cells demonstrated that the MUC4 and ErbB2 are present as a complex in airway epithelial cells. To assess the participation of MUC4 in the damage response, cultures of NCI‐H292 or airway cells were scratch‐wounded, then analyzed for association of phospho‐ErbB2 and ‐ErbB3 with MUC4 by sequential immunoprecipitation and immunoblotting. Wounded cultures exhibited increased phosphorylation of both receptors in complex with MUC4. Scratch wounding also increased activation of the downstream pathway through Akt, as predicted from our previous studies on Muc4 effects on ErbB2 and ErbB3. The participation of MUC4 in the phosphorylation response was also indicated by siRNA repression of MUC4 expression, which resulted in diminution of the phosphorylation of ErbB2 and ErbB3. These studies provide a new model for the airway epithelial damage response, in which the MUC4–ErbB2 complex is a key element in the sensor mechanism and phosphorylation of the receptors. J. Cell. Biochem. 107: 112–122, 2009. © 2009 Wiley‐Liss, Inc.     

<Superscript>15</Superscript>N natural abundance of fossil peat reflects the influence of animal-derived nitrogen on vegetation

'¹⁵N signatures of fossil peat were used to interpret past ecosystem processes on tectonically active subantarctic Macquarie Island. By comparing past vegetation reconstructed from the fossil record with present-day vegetation analogues, our evidence strongly suggests that changes in the '¹⁵N signatures of fossil peat at this location reflect mainly past changes in the proportion of plant nitrogen derived from animal sources. Associated with uplift above sea level over the past 8,500 years, fossil records in two peat deposits on the island chronicle a change from coastal vegetation with fur and elephant seal disturbance to the existing inland herbfield. Coupled with this change are synchronous changes in the '¹⁵N signatures of peat layers. At two sites ¹⁵N-enriched peat '¹⁵N signatures of up to +17‰ were associated with a high abundance of pollen of the nitrophile Callitriche antarctica (Callitrichaceae). At one site fossil seal hair was also associated with enriched peat '¹⁵N. Less ¹⁵N enriched '¹⁵N signatures (e.g. -1.9‰ to +3.9‰) were measured in peat layers which lacked animal associated C. antarctica and Acaena spp. Interpretation of a third peat profile indicates continual occupation of a ridge site by burrowing petrels for most of the Holocene. We suggest that ¹⁵N signatures of fossil peat remained relatively stable with time once deposited, providing a significant new tool for interpreting the palaeoecology.     

Within-tree spatial variation in the leaf monoterpenes of Sequoia sempervirens

Location within a tree was analyzed as a source of variation in Sequoia sempervirens leaf monoterpenes. No differences were found for quantitative composition or total yield/dry wt among lower, middle and upper canopy positions. The awlshaped, spirally arranged leaves of vigorous upper shoots showed small quantitative compositional differences, but not differences in total yield. The intermediate leaf form of young sprouts had the most different monoterpene quantitative composition and about three times the total yield of the above two leaf forms. Analysis of a clonal ring of 17 adult trees resulted in coefficients of variation similar to those for samples collected from different canopy levels of the same shoot. Results revealed the sources and magnitudes of experimental error in comparative studies of this species' leaf monoterpenes, and did not support the concept that somatic mutation provides an important source of variation in a large, long-lived organism such as coast redwood.     

Alterations in high-affinity binding characteristics and levels of opioids in invertebrate ganglia during aging: Evidence for an opioid compensatory mechanism

In Mytilus and Leucophaea the high-affinity binding site density is significantly lower in old animals than in young animals, whereas the low-affinity site density remains unchanged. In Mytilus the estimated met-enkephalin and met-enkephalin-Arg6-Phe7 levels are significantly higher in old than in young animals. In Leucophaea only the met-enkephalin level can be determined, and it is also higher in old animals. The decrease in the high-affinity binding site density and the corresponding increase in endogenous enkephalin levels suggest the existence of an opioid compensatory mechanism associated with the aging process. In Mytilus there is a demonstrated decrease with age in intraganglionic dopamine levels in response to applied opiates. In addition, the inhibition of dopamine-stimulated adenylate cyclase activity by opiates also decreases in older animals. In Leucophaea the sex difference in opioid binding densities diminishes with age.     

Synthesis of fibronectin in normal and osteoarthritic articular cartilage

The content and the biosynthesis of fibronectin was examined in disease-free articular cartilage and in articular cartilage from osteoarthritic canine joints. Fibronectin content was increased in extracts of cartilage from osteoarthritic joints. Incubation of cartilage in vitro with [³H]phenylalanine and subsequent isolation of [³H]fibronectin from a gelatin affinity column and characterization by SDS-polyacrylamide gel electrophoresis and by immunoprecipitation indicated that disease-free and osteoarthritic cartilage explants synthesized fibronectin. About 50% of the [³H]fibronectin was recovered in the incubation medium. The osteoarthritic cartilage synthesized and accumulated up to 5-fold more [³H]fibronectin than disease-free cartilage.     

A simple procedure to obtain one-micrometer sections of routinely embedded paraffin material

By freezing blocks of paraffin-embedded tissues to a convenient temperature it is possible to obtain routinely 1 micron sections that can be further processed as normal thicker sections. Normal and disposable steel knives can be used and the staining time should be increased in most procedures. Gradual freezing of blocks to the temperature of dry ice is the simplest and safest way to obtain an adequate temperature. The best results were obtained using as fixative 4% paraformaldehyde in phosphate buffered saline solution.     

Rare earth thiocyanate complexes with tripiperidinophosphine oxide: synthesis and characterization. Crystal structure of Pr(SCN)3(tpppO)3

The synthesis and characterization of rare-earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) thiocyanate adducts with tripiperidinophosphine oxide (tpppO) with general formula (RE)(SCN)₃(tpppO)₃ are reported. Conductance measurements in acetonitrile indicate the non-electrolytic nature of the complexes. Infrared absorption spectra evidence that the SCN⁻ ion coordinates through the nitrogen atom (isothiocyanate form) and that tpppO coordinates through the phosphoryl oxygen. X-ray powder patterns suggest the existence of three different crystal forms: (1) La; (2) an isomorphous series including Ce, Nd and Pr; and (3) another isomorphous series, including Sm, Gd, Eu, Ho, Er, Tb, Lu and Y. The visible spectra of the Nd adduct and the calculated parameters β = 0.98, b^1/2 = 0.072 and δ = 1.06 indicate that the metal-ligand bonds are essentially electrostactic. The emission spectra of the Eu compound showed ⁵D₀ → ⁷F_J bands (J = 0, 1, 2), suggesting a C_3v symmetry for the coordination polyhedron. The lifetime of the ⁵D₀ state is 1.28 ms. The emission spectra of the Tb complex presented ⁵D₄ → ⁷F_J bands (J = 4, 5, 6) and the Dy complex showed the ⁴F_9/2 → ⁶H_13/2 band. The structure of the Pr complex showed that the coordination polyhedron is a trigonal antiprism, with the isothiocyanate anions in one base and three tpppO ligands in the other. Thermal analyses (TG-DTG) were carried out for the Ce, Nd and Gd adducts. Mass losses start between 250 and 334 °C. The final residues at 1300 °C are the corresponding phosphates.     

Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) parasitizing terrestrial isopods (Isopoda: Oniscoidea)

Summary A new mermithid nematode, Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) was found parasitizing two terrestrial isopods (Isopoda: Oniscoidea) in California. The hosts, Armadillidium vulgare (Latr.) (a pillbug) and Porcellio scaber (Latr.) (a sowbug) represent the first cases of isopods attacked by mermithid nematodes. The genus Thaumamermis can be distinguished from all previously described mermithids by the extremely dimorphic spicules, one being short and broad and the other long and filiform. It has been discovered that the nematodes are infected with an iridiovirus which commonly destroys the isopod hosts. ac]19800917