Vessel development in compound buds of interspecific hybrid grape induced by artificial deacclimation treatments.

Grape compound buds adapt to subfreezing temperatures in winter by supercooling, but the supercooling ability is thought to be lost upon formation of xylem connections between canes and buds. It was reported that compound buds of the Vitis vinifera variety 'Chardonnay' lack xylem cells in mid-winter, and that vessels differentiate during deacclimation. However, the pattern of vessel formation in compound buds may differ in cold-hardy Vitis species and interspecific hybrid varieties grown in colder regions. We investigated vessel formation in compound buds of the interspecific hybrid variety 'Yamasachi', which were harvested in mid-winter, during artificial deacclimation treatments. Before these treatments, 'Yamasachi' buds had a high supercooling ability (approx. -30°C) and contained cells with characteristics of vessel elements, that is, secondary wall thickening and lignification, at the basal parts. However, the cells still contained organelles and did not have a hydraulic conductivity function. Xylem continuity between the canes and buds was established from day 7 of deacclimation at 20°C. The different pattern of seasonal vessel formation in compound buds of 'Yamasachi' from that of V. vinifera may reflect the rapid development traits of Vitis species growing in cold regions with short growing seasons.

Further characterization of distinct high-affinity binding sites for dinotefuran in the abdominal nerve cord of the American cockroach Periplaneta americana (Blattodea).

Dinotefuran (DTF) is a systemic neonicotinoid insecticide characterized by a tetrahydrofuran ring. In the present study, we examined the characteristics of DTF binding to native nicotinic acetylcholine receptors (nAChRs) expressed in the American cockroach Periplaneta americana using radioligand-binding methods. The Scatchard analysis, using [3H]imidacloprid (IMI), indicated that IMI has a single class of high-affinity binding sites in the P. americana nerve cord. In contrast, the Scatchard analysis using [3H]DTF indicated that DTF has two different classes of binding sites. Both DTF and IMI were found to bind to one of the classes, for which DTF showed low affinity. The other class, for which DTF showed high affinity, was localized in the abdominal nerve cord but not in the thoracic nerve cord. IMI showed low affinity for the high-affinity DTF binding sites. Our data suggest that DTF binds with high affinity to a nAChR subtype distinct from the high-affinity subtype for IMI. This difference might be responsible, at least in part, for the difference in resistance development to DTF and IMI in P. americana.

The A2'N mutation of the RDL gamma-aminobutyric acid receptor conferring fipronil resistance in Laodelphax striatellus (Hemiptera: Delphacidae).

The planthopper Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae) is a serious insect pest of rice, Oryza sativa L., and has developed resistance to fipronil in Japan. Sequence analysis of L. striatellus RDL gamma-aminobutyric acid (GABA) receptor subunit (LS-RDL) genes from a fipronil-resistant population and a fipronil-susceptible strain identified the A2'N mutation (index number for M2 membrane-spanning region), that was previously implicated in fipronil resistance in the planthopper Sogatella furcifera (Horváth) (Hemiptera: Delphacidae). Nineteen of 21 fipronil-resistant L. striatellus individuals were genotyped as heterozygous for the A2'N mutation, suggesting that this mutation is associated with fipronil resistance and that most fipronil-resistant L. striatellus express wild-type and A2'N mutant LS-RDL simultaneously. To confirm the role of the A2'N mutation of LS-RDL, Drosophila Mel-2 cells were transfected with wild-type and A2'N mutant LS-RDL genes, either individually or together. A membrane potential assay showed that fipronil had no inhibitory effect at 10 microM on cells transfected with the A2'N mutant LS-RDL gene with or without the wild-type LS-RDL gene. By contrast, the IC50 value of fipronil for wild-type LS-RDL homomers was 14 nM. These results suggest that the A2'N mutation of the RDL GABA receptor subunit confers fipronil resistance in L. striatellus as well as S. furcifera.

Proteomic analysis of immature murine melanocytes at different stages of maturation: a crucial role for calreticulin.

BACKGROUND: We have established two immature melanocyte cell lines from murine neural crest cells. NCC-E3 cells have Stage II melanosomes and express tyrosinase while in NCCmelb4 cells, the melanosomes remain at Stage I and tyrosinase is not expressed. These cell lines may be useful in studying the differentiation of melanocyte precursors. OBJECTIVE: To perform proteomic analysis of the two cell lines to identify proteins related to and possibly responsible for their different maturation stages. METHODS: Western blotting, two-dimensional differential image gel electrophoresis (2D-DIGE), liquid chromatography-tandem mass spectrometry (LC-MS/MS), real-time PCR analysis and RNA interference using siRNA were employed in this study. RESULTS: Western blotting revealed that the processed form of gp100, which is specific for Stage II melanosomes, is expressed in NCC-E3 cells but not in NCCmelb4 cells. 2D-DIGE identified two protein spots showing 4.06- and 2.22-fold increases in NCC-E3 cells compared to NCCmelb4 cells. Analysis of those proteins by LC-MS/MS revealed that the former was calreticulin and the latter was BiP/GRP78. When calreticulin mRNA expression in NCC-E3 cells was blocked by siRNA, tyrosinase protein was abolished and DOPA-reactivity was decreased, although tyrosinase mRNA was abundantly expressed after the same treatment. CONCLUSION: Calreticulin, a lectin chaperone, is an essential molecule for the processing of tyrosinase in murine melanocytes. The role of molecular chaperones such as calreticulin should be considered when analyzing the mechanism(s) of melanocyte differentiation.

Initial cutaneous manifestations consistent with mononeuropathy multiplex in Churg-Strauss syndrome.

BACKGROUND: Churg-Strauss syndrome (CSS), also known as allergic granulomatous angiitis, is a rare entity that is characterized by systemic vasculitis in patients with a history of asthma. Patients with CSS show a marked peripheral blood eosinophilia, but the pathogenesis remains unknown. OBSERVATIONS: A retrospective review was performed in 9 cases of CSS in whom cutaneous findings were present as an initial manifestation. All 9 patients had purpura and petechiae as well as severe pain and paresthesias of the lower extremities. Four patients (44%) used leukotriene receptor antagonists to treat their asthma, and 3 (75%) of them developed CSS within 3 months. Five patients (56%) were positive for perinuclear antineutrophil cytoplasmic antibodies before therapy, but in all 5 the levels of perinuclear antineutrophil cytoplasmic antibody normalized. Serum IgE levels were elevated in all patients before treatment but decreased after treatment. Histologically, all patients demonstrated leukocytoclastic vasculitis and eosinophilic infiltration. Eight biopsy specimens (73%) revealed marked eosinophilia around the nerve fibers in the dermis. Palisading granulomas in association with vessel-based changes were present in 4 (36%) of 11 biopsy specimens. CONCLUSIONS: These characteristic cutaneous clinical patterns that are consistent with the presence of mononeuropathy multiplexes in the lower extremities may help physicians establish an earlier diagnosis. Both eosinophils and IgE, as well as perinuclear antineutrophil cytoplasmic antibodies to some degree, likely participate in skin lesion development in CSS. Furthermore, there appears to be a correlation between treatment with leukotriene receptor antagonists and the onset of CSS in some cases.