<Emphasis Type="Italic">Nicotiana debneyi</Emphasis> has a single dominant gene causing hybrid lethality in crosses with <Emphasis Type="Italic">N. tabacum</Emphasis>

To elucidate the genetic mechanism of hybrid lethality observed in hybrids between cultivated tobacco, Nicotiana tabacum, and wild tobacco species in the section Suaveolentes, genetic analyses were conducted through the triple cross of the hybrids of wild species, including N. benthamiana and N. fragrans, and N. tabacum. N. benthamiana and N. fragrans produced only viable hybrids after crossing with N. tabacum. Subsequently, N. benthamiana and N. fragrans were crossed with N. africana, N. debneyi, and/or N. suaveolens, which produced inviable hybrids after crossing with N. tabacum. Hybrids of the wild species were obtained from four of the six cross combinations. Only when hybrid plants of N. debneyi × N. fragrans, whose hybridity was confirmed by morphological characteristics, random amplified polymorphic DNA analysis, and chromosome observation, were crossed with N. tabacum, triple hybrids were obtained and segregated 1:1 (lethal:viable). Based on these results, a single dominant gene, designated Hybrid Lethality A1 (HLA1), in N. debneyi was found to control hybrid lethality by the interaction with gene(s) on the Q chromosome in N. tabacum. This represents the first report to identify a causal gene for hybrid lethality in the genus Nicotiana.     

Properties of tofus and soy milks prepared from soybeans having different subunits of glycinin

The contribution of soybean protein to the physical properties of tofu, a product manufactured by curdling soy milk with coagulants such as calcium or magnesium chloride, was studied by comparing the properties of soy milk prepared from soybeans with different subunits (I, IIa, and IIb) of glycinin with amino acid residues deleted. The breaking stress value of the tofu curds prepared from soybeans having group I was higher than those without group I. The soy milks having group I contained more protein particles and showed more sensitivity to calcium and magnesium ions than those without group I. The amounts of glycinin and protein particles were higher in the soy milks having group I than those in the soy milks without group I. To elucidate the influence of each group on the breaking stress, the glycinin content was adjusted to an identical level in soy milks having each group. Among the tofu curds from three groups, their order of hardness according to their breaking stress was IIa, IIb, and I. The order of particle content among these soy milks was also IIa, IIb, and I. Therefore, the results suggested that the breaking stress value of the tofu curd is dependent upon the number of protein particles in the soy milk and that the number of the particles is determined by the proportion and structure of glycinin in the soybean.     

Mitigation of aluminum toxicity by calcium and magnesium in Japanese cedar (Cryptomeria japonica)

We investigated the short-term and long-term mitigation of Al toxicity by Ca and Mg in pot trials of Japanese cedar (Cryptomeria japonica D. Don). We found that in the initial stages of treatment, Al toxicity at high Al concentration (5mM) was mitigated by Ca and Mg through the stimulation of antioxidant enzyme activities in needles. However, growth reduction occurred after 11 months exposure to Al despite the coexistence of Ca and Mg. Growth reduction was related to Al³⁺ activity in solution rather than the concentration of Ca and Mg. Therefore, when considering the influence of soil acidification on Al toxicity in forest ecosystems, it is important to consider not only the potential for mitigation of Al toxicity by base cations, but also the potential for factors in the soil solution to change the chemical form of Al.     

Changes in characters of soybean glycinin groups I, IIa, and IIb caused by heating

Soybean glycinin groups I, IIa, and IIb were purified from soybeans composed of only glycinin groups I, IIa, and IIb, respectively. When these protein solutions were heated, the amount of the particulate protein formed in these solutions was greatest in the order of groups IIa, IIb, and I. The protein solubilities decreased upon the addition of magnesium chloride in the order of groups IIa, IIb, and I. It was determined by differential scanning calorimetry analysis that the denaturation temperatures of groups I, IIa, and IIb were 92.8, 96.0, and 97.9 degrees C, and that the enthalpies of their transitions were 24.2, 27.4, and 28.1 J g(-)(1), respectively. The alpha-helix rates of groups I, IIa, and IIb in aqueous solution were analyzed by circular dichroism and were 19, 16, and 15%, respectively. The beta-sheet rates of groups I, IIa, and IIb were 44, 38, and 39%, respectively. In all group proteins, the alpha-helix rates were decreased by heating and the beta-sheet rates were increased. The surface hydrophobicity of these group proteins increased as a result of heating, and those of groups IIa and IIb were larger than that of group I. The surface hydrophobicity of these protein groups increased by heating, and those of groups IIa and IIb were larger than that of group I and beta-conglycinin. Breaking stress of curds prepared from these group proteins containing more than 1 of beta-conglycinin ration showed similar values, but the order of those containing less than 1 in strength was groups I, IIb and IIa. These results suggest that the increase of particulate contents and the curd formation are related to the increase of surface hydrophobicity by heating.     

Spatial structures of N2O, CO2, and CH4 fluxes from Acacia mangium plantation soils during a relatively dry season in Indonesia

We investigated spatial structures of N₂O, CO₂, and CH₄ fluxes during a relatively dry season in an Acacia mangium plantation stand in Sumatra, Indonesia. The fluxes and soil properties were measured at 1-m intervals in a 1 × 30-m plot (62 grid points) and at 10-m intervals in a 40 × 100-m plot (55 grid points) at different topographical positions of the upper plateau, slope, and valley bottom in the plantation. Spatial structures of each gas flux and soil property were identified using geostatistical analysis. The means (±SD) of N₂O, CO₂, and CH₄ fluxes in the 10-m grids were 0.54 (±0.33) mg N m⁻² d⁻¹, 2.81 (±0.71) g C m⁻² d⁻¹, and −0.84 (±0.33) mg C m⁻² d⁻¹, respectively. This suggests that A. mangium soils function as a larger source of N₂O than natural forest soils in the adjacent province on Sumatra during the relatively dry season, while CO₂ and CH₄ emissions from the A. mangium soils were less than or consistent with those in the natural forest soils. Multiple spatial dependence of N₂O fluxes within 3.2 m (1-m grids) and 35.0 m (10-m grids), and CO₂ fluxes within 1.8 m (1-m grids) and over 65 m (10-m grids) was detected. From the relationship among N₂O and CO₂ gas fluxes, soil properties, and topographic elements, we suggest that the multiple spatial structures of N₂O and CO₂ fluxes are mainly associated with soil resources such as readily mineralizable carbon and nitrogen in a relatively dry season. The soil resource distributions were probably controlled by the meso- and microtopography. Meanwhile, CH₄ fluxes were spatially independent in the A. mangium soils, and the water-filled pore space appeared to mainly control the spatial distribution of these fluxes.     

Temperature controls temporal variation in soil CO2 efflux in a secondary beech forest in Appi Highlands, Japan

Forest soil is a huge reserve of carbon in the biosphere. Therefore to understand the carbon cycle in forest ecosystems, it is important to determine the dynamics of soil CO₂ efflux. This study was conducted to describe temporal variations in soil CO₂ efflux and identify the environmental factors that affect it. We measured soil CO₂ efflux continuously in a beech secondary forest in the Appi Highlands in Iwate Prefecture for two years (except when there was snow cover) using four dynamic closed chambers that automatically open after taking measurements. Temporal changes in soil temperature and volumetric soil water content were also measured at a depth of 5 cm. The soil CO₂ efflux ranged from 14 mg CO₂ m⁻² h⁻¹ to 2,329 mg CO₂ m⁻² h⁻¹, the peak occurring at the beginning of August. The relationship between soil temperature and soil CO₂ efflux was well represented by an exponential function. Most of temporal variation in soil CO₂ efflux was explained by soil temperature rather than volumetric soil water content. The Q ₁₀ values were 3.7 ± 0.8 and estimated annual carbon emissions were 837 ± 210 g C m⁻² year⁻¹. These results provide a foundation for further development of models for prediction of soil CO₂ efflux driven by environmental factors.     

Production of a monoclonal antibody to canine thymus and activation-regulated chemokine (TARC) and detection of TARC in lesional skin from dogs with atopic dermatitis

A monoclonal antibody to canine thymus and activation-regulated chemokine (TARC/CCL17) was developed to examine the association of TARC with the immunopathogenesis of canine atopic dermatitis (AD). Recombinant canine TARC was prepared using an E. coli expression system. Results of transwell chemotaxis assay demonstrated that the recombinant canine TARC showed chemotactic activity for canine lymphoid cells expressing CC chemokine receptor 4 (CCR4). Mice were then immunized with the recombinant canine TARC to obtain monoclonal antibodies. Among the monoclonal antibodies thereby obtained, one monoclonal antibody (CTA-1) was found to react with both recombinant and authentic canine TARC in ELISA and flowcytometric assays, respectively. Immunohistochemical analysis using the monoclonal antibody CTA-1 demonstrated that keratinocytes were major TARC producing cells in lesional skin of dogs with AD.     

Systemic activity of simeconazole and its derivatives in plants

The systemic activity of simeconazole (RS-2-(4-fluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-3-trimethylsilylpropan-2-ol) and a number of its derivatives in plants has been investigated to establish which portion of the structure of the molecule contributes to this outstanding activity. The results revealed that the hydroxyl group of the simeconazole moiety is essential for vapour-phase activity and translocation from roots of the compound. They showed that the presence of a fluorine atom in the structure was not indispensable for vapour-phase activity or translocation from roots, although the fluorine atom contributed to these systemic movements. In addition, it was found that the fungicidal activity of simeconazole against Rhizoctonia solani Kühn and Blumeria graminis DC fsp hordei Marchal is potentiated by the fluorine atom, since the activity of a compound which lacked fluorine in the 4-position of the phenyl ring was inferior to that of simeconazole. A compound in which the silicon atom of simeconazole was replaced by a carbon atom showed lower antifungal activity than simeconazole, while phytotoxicity was caused in rice plants by soil drench of the compound. Therefore, the silicon atom of simeconazole may contribute to its selectivity between fungi and plants.     

Cytokine profiles of peripheral blood mononuclear cells from dogs experimentally sensitized to Japanese cedar pollen

Japanese cedar (Cryptomeria japonica, CJ) pollinosis is mediated by type-I hypersensitivity and induces seasonal rhinitis and conjunctivitis in humans. Previous studies showed that dogs could be experimentally sensitized with CJ pollen. In this study, we carried out quantitative analysis of mRNA levels of various cytokines in the peripheral blood mononuclear cells (PBMC) of 12 dogs experimentally sensitized to Japanese cedar pollen. Experimental sensitization was carried out by injection of crude CJ pollen extract with aluminium hydroxide gel. The expression levels of interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-18, interferon (IFN)-gamma, transforming growth factor (TGF)-beta(1), and tumor necrosis factor (TNF)-alpha mRNAs in the PBMC were quantified using a real-time sequence detection system. In the PBMC tested without culture, the expression levels of IL-8 and TNF-alpha mRNAs in experimentally sensitized dogs were significantly higher than those in control dogs. The expression level of IFN-gamma mRNA in the sensitized group was significantly lower than that in the control group. When the PBMCs were cultured in the presence of CJ pollen extract, the level of IL-4 mRNA expression was markedly increased in the PBMC from the experimentally sensitized dogs. In the PBMC stimulated with the CJ pollen extract, the expression level of IL-2 mRNA in the sensitized group was also significantly higher than that in the control group. Our data indicated that a Th2 response and proliferation of PBMC occur in response to the sensitizing antigen in dogs experimentally sensitized with CJ pollen, and revealed the presence of antigen-specific Th2 cells in this canine model. In addition, the expression levels of the mRNAs encoding proinflammatory cytokines were shown to be elevated after CJ pollen sensitization, indicating the activation of monocytes and macrophages.     

Myxoid leiomyosarcoma of the gizzard in a broiler chicken

A leiomyosarcoma was found in the gizzard of a 57-day-old female broiler chicken weighing 1.8 kg. Grossly, the tumor mass, 13.0 x 8.5 x 10.0 cm, enveloped the gizzard and had a gelatinous appearance due to the rich production of mucin. Miliary metastatic tumors were noted in the liver. Histopathologically, there was marked production of mucus throughout the tumor tissue, and densely or loosely arranged long spindle-shaped leiomyosarcoma cells proliferated. The tumor cells had a low rate of mitosis, showed slight cellular atypia, and, immunohistochemically, were positive for actin, alpha-smooth muscle actin, and desmin. Electron microscopically, various amounts of microfibrils with focal densities, dense patches, and basal plates were observed.