Latent 1,3-ß-D-glucan acts as an adjuvant for allergen-specific IgE production induced by Japanese cedar pollen exposure.

BACKGROUND: The pollen grains of several plant species contain 1,3-ß-D-glucan (BG). BG activates dendritic cells (DCs) and subsequently regulates the innate immune responses. Within Japan, the most common disease associated with type-I hypersensitivity is Japanese cedar pollinosis. However, the role of BG in Japanese cedar pollen (JCP) remains unclear. This study examined the localization and immunological effects of BG in JCP. METHODS: The localization of BG in JCP grain was determined by immunohistochemical staining using a soluble dectin-1 protein probe and a BG recognition protein (BGRP). The content of BG extracted from JCP was measured by a BGRP-based ELISA-like assay. The cytokine production by bone marrow-derived DCs (BMDCs) obtained from wild-type and BG receptor (dectin-1) knock-out mice was examined in vitro. The mice were intranasally administered JCP grains and the specific serum Ig levels were then quantified. RESULTS: BG was detected in the exine and cell wall of the generative cell and tube cell of the JCP grain. Moreover, BG in the exine stimulated production of TNF-α and IL-6 in the BMDCs via a dectin-1-dependent mechanism. Meanwhile, JCP-specific IgE and IgG were detected in the serum of wild-type mice that had been intranasally administered with JCP grains. These mice also exhibited significantly enhanced sneezing behavior. However, dectin-1 knock-out mice exhibited significantly lower JCP-specific IgE and IgG levels compared to wild-type mice. CONCLUSIONS: Latent BG in JCP can act as an adjuvant to induce JCP-specific antibody production via dectin-1.

[Clinical Utility of Tapentadol].

Tapentadol(TP)is a new strong opioid analgesicthat has both m-opioid receptor(MOR)effects and norepinephrine reuptake inhibitor(NRI)effects. In comparison with the existing strong opioid analgesics, the mechanism of action suitable for palliation of neuropathic pain is expected to be better for TP. The analgesic effect and side effects of this drug were tested in 10 cases of exacerbation of neuropathic pain at our hospital, and the sedative response rate was 70%. The main side effects were somnolence 44.4%, nausea 33.4%, and constipation 11.1%. The side effects on the digestive system were considered minimal. Although it is speculated that opioids would be useful as an outpatient treatment, few case reports are available regarding their use for cancer pain; therefore, further investigation is necessary. Generally, numerous social issues that would increase the likelihood of drug adherence failure must be addressed in order to expand the use of strong opioid analgesics such as TP. Both the patients and the healthcare worker should be involved when addressing these issues in Japan, and the measures should include instructions for appropriate reporting and for using such drugs.

Pollen tube reuses intracellular components of nucellar cells undergoing programmed cell death in Pinus densiflora.

Through the process known as programmed cell death (PCD), nucelli of Pinus densiflora serve as the transmitting tissue for growth of the pollen tube. We sought to clarify the processes of degradation of nucellar cell components and their transport to the pollen tube during PCD in response to pollen tube penetration of such nucelli. Stimulated by pollination, synthesis of large amounts of starch grains occurred in cells in a wide region of the nucellus, but as the pollen tube penetrated the nucellus, starch grains were degraded in amyloplasts of nucellar cells. In cells undergoing PCD, electron-dense vacuoles with high membrane contrast appeared, assumed a variety of autophagic structures, expanded, and ultimately collapsed and disappeared. Vesicles and electron-dense amorphous materials were released inside the thickened walls of cells undergoing PCD, and those vesicles and materials reaching the pollen tube after passing through the extracellular matrix were taken into the tube by endocytosis. These results show that in PCD of nucellar cells, intracellular materials are degraded in amyloplasts and vacuoles, and some of the degraded material is supplied to the pollen tube by vesicular transport to support tube growth.

Evolution of shoot apical meristem structures in vascular plants with respect to plasmodesmatal network.

Vascular plants have evolved shoot apical meristems (SAMs), whose structures differ among plant groups. To clarify the evolutionary course of the different structural types of SAMs, we compared plasmodesmatal networks in the SAMs for 17 families and 24 species of angiosperms, gymnosperms, and pteridophytes, using transmission electron microscopy (TEM). The plasmodesmata (PD) in almost all cell walls in median longitudinal sections of SAMs were counted, and the PD density per unit area was calculated for each cell wall. Angiosperm and gymnosperm SAMs have low densities, with no difference between stratified (tunica-corpus) and unstratified structures. SAMs of ferns, including Psilotum and Equisetum, have average densities that are more than three times higher than those of seed plants. Interestingly, microphyllous lycopods have both the fern and seed-plant types of PD networks; Selaginellaceae SAMs with single apical cells have high PD densities, while SAMs of Lycopodiaceae and Isoetaceae with plural initial cells have low PD densities, equivalent to those of seed plants. In summary, PD networks are strongly correlated to SAM organizations-SAMs with single and plural initial cells have the fern and seed-plant types of PD, respectively. The two SAM organizations may have evolved separately in lycophytes and euphyllophytes and may be associated with gain or loss of the ability to form secondary PD.

Programmed cell death of Pinus nucellus in response to pollen tube penetration.

In ovules of Pinus densiflora, pollen tubes elongate and branch into the nucellar tissue in the direction of the female gametophyte. After pollination, nucellar cells located around the pollen grain and tube die off. We showed here that the nuclei of the nucellar cells were stained by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick end labeling). The number of TUNEL-positive cells increased during pollen tube growth. The tips of pollen tube branches protruded into the nucellar cells to form a convex-concave junction. At this junction, the cell membrane of nucellar cells was separated from the cell wall and the protoplast shrank. Small vesicles and amorphous materials were released from the protoplast into the space between the cell membrane and wall. Vacuoles were collapsed, chromatin was condensed, and mitochondria and plastids were deteriorated in the shrunken protoplast. Agarose gel analysis of DNA isolated from the ovules showed a DNA ladder, suggesting that the nuclear DNA had undergone internucleosomal cleavage. These results suggest that nucellar cells undergo programmed cell death in response to pollen tube penetration with some features resembling apoptosis and other features peculiar to nucellar cells.