Temporally and spatially controlled death of parenchyma cells is involved in heartwood formation in pith regions of branches of <Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> var. <Emphasis Type="Italic">inermis</Emphasis>

Focussing on four types of parenchyma cell around pith regions of branches of Robinia pseudoacacia L. var. inermis, we examined the timing and role of cell death during heartwood formation. Large parenchyma cells that were located in the inner part of the pith died within a year. By contrast, other parenchyma cells died within 4 years, with the timing of cell death depending on the type of cell. Axial parenchyma cells of the xylem close to the pith died first. Then, small parenchyma cells died in the perimedullary zone in the outer part of the pith. Finally, ray parenchyma cells in the xylem close to the pith died. Variations in the autofluorescence of cell walls, which might have been due to deposition of heartwood substances, were observed first in xylem ray parenchyma cells and small parenchyma cells in the perimedullary zone. Our results indicate that the initiation of heartwood formation occurs within 4 years in pith regions of branches in Robinia pseudoacacia L. var. inermis. Moreover, it appears that not only xylem ray parenchyma cells but also small parenchyma cells in the perimedullary zone might be involved in the synthesis of heartwood substances.     

Tracheary elements that resemble secondary xylem in calli derived from the conifers, Torreya nucifera and Cryptomeria japonica

Differentiated cells were recognized in calli derived from needles of Torreya nucifera and in calli derived from immature zygotic embryos of Cryptomeria japonica. Some differentiated cells resembled tracheary elements of primary xylem with spiral or reticulate thickening of cell walls. Other cells resembled tracheary elements with thick cell walls and bordered pits, which are features of secondary xylem. These tracheary elements were formed in cell clusters. Tracheary elements in calli of T. nucifera formed more highly developed structures, such as bordered pits and spiral thickening, than those of C. japonica. Cultured cells derived from conifers might provide a good model for studies of the differentiation of secondary xylem in vitro.     

Radial variations in the anatomical characteristics and density of the wood of Acacia mangium of five different provenances in Indonesia

The anatomical characteristics and density of wood were examined in 23-year-old Acacia mangium trees that had been planted in Yogyakarta, Indonesia. The seeds had been collected from trees of five different provenances. The distance from the pith of the boundary between juvenile and mature wood was also examined to clarify the maturity of the wood. Lengths of wood fibers near the pith and the distance from the pith of the boundary between juvenile and mature wood differed significantly among provenances. By contrast, other anatomical characteristics of the wood such as fiber wall area, fiber wall thickness, fiber diameter, vessel lumen area, vessel diameter, vessel frequency and wood density did not differ significantly among provenances. Wood density was strongly correlated with the area of fiber walls. Our observations suggest that Sidei and Daintree might be more appropriate provenances among those examined for the Acacia mangium tree-breeding programs in Indonesia that are aimed at improving wood quality, because these provenances are associated with longer initial wood fibers and narrower juvenile areas than the other provenances studied.     

Time‐coordinated prevalence of extracellular HGF,FGF2 and TGF‐β3 in crush‐injured skeletal muscle

Successful regeneration and remodeling of neuromuscular junctions are critical for restoring functional capacities and properties of skeletal muscle after damage, and axon‐guidance molecules may be involved in the signaling that regulates such restoration. Recently, we found that early‐differentiated satellite cells up‐regulate a secreted neural chemorepellent Sema3A upon in vivo muscle‐crush injury. The study also revealed that Sema3A expression is up‐regulated in primary satellite‐cell cultures in response to hepatocyte growth factor (HGF) and basic fibroblast growth factor (FGF2) and is prevented by transforming growth factor (TGF)‐β2, 3. In order to verify the physiological significance of this regulation in vitro, the present study was designed to estimate the time‐course of extracellular HGF, FGF2 and TGF‐β3 concentrations after crush‐injury of Gastrocnemius muscle in the rat lower hind‐limb, using a combination of a non‐homogenization/non‐spin extraction of extracellular wound fluids and enhanced chemiluminescence–Western blotting analyses. Results clearly demonstrated that active HGF and FGF2 are prevalent in 2–8 days post‐crush, whereas active TGF‐β3 increases after 12 days, providing a better understanding of the time‐coordinated levels of HGF, FGF2 and TGF‐β3 that drive regulation of Sema3A expression during regenerative intramuscular moto‐neuritogenesis.     

Bioassay-guided isolation of a novel chemoattractant for <Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> in tomato root exudates

Tomato root exudates were analyzed using a bioassay to detect the chemoattractant for Ralstonia solanacearum. An activated charcoal-adsorbed fraction of root exudates from tomato cultivar Oogata-fukuju had chemoattractant activity for R. solanacearum strain MAFF 730138. The active component, purified using a Sep-Pak C18 cartridge, an activated charcoal column, diol-modified silica gel, and NH₂-modified silica gel, is a new hydrophobic attractant. The final purified fraction produced a single peak in a diol-modified silica gel HPLC analysis.     

Application of timed artificial insemination protocols to grazing Japanese black cattle with long open period

To investigate the viability of timed artificial insemination (TAI) protocols in grazing Japanese Black cattle with long open period, ovarian status and progesterone and estradiol-17 beta profiles of the animals during the protocol were monitored. In 1998, prosta-glandin F(2a) (PG) was administered to 36 animals seven days after GnRH injection. Three out of the 36 animals were inseminated after detection of estrus and did not receive further treatment. The second GnRH was injected to the remaining 33 animals 48 hr after the PG injection and TAI was performed 24 hr later. In 1999, PG was injected to 25 animals six days after GnRH, the second GnRH was injected to 22 animals 48 hr after PG, and TAI was performed 16 hr later (The other three animals were inseminated before the time of TAI). The percentage of the animals with at least one functional corpus luteum and one follicle equal to or greater than 10 mm in diameter at PG injection was similar between the groups in 1998 and 1999. Likewise, the hormonal profiles were similar between the two groups. Pregnancy rates (PR) after the TAI protocols and natural mating in 1998 and 1999 were 75.0% and 88.0%, respectively. These figures were comparable to the PR obtained by conventional estrus synchronization protocols using PG (in 1995; 69.4%) or CIDR (in 1996; 59.1%). In conclusion, the TAI protocol can be applicable into grazing Japanese Black cattle with long open period.     

Behavior, performance and physical condition of laying hens in conventional and small furnished cages

The aim of the present study was to compare the welfare level and performance of laying hens between conventional and small furnished cages. At the age of 54 weeks, 120 White Leghorn layers were divided into four groups: four (C4) or six hens/cage in conventional cages and four or six (F6) hens/cage in furnished cages. Their behavior, number of steps taken, performance and physical condition were measured. Sham dust‐bathing was greater in conventional cages than in furnished cages (P = 0.05) and dust‐bathing, litter scratching and litter pecking were also observed in furnished cages. Other comfort behavior, moving and number of steps taken were more frequent in the four‐hen cages than in the six‐hen cages (P < 0.01, P < 0.001, P < 0.001, respectively). Though egg production and egg mass in C4 and F6 were lower than in the other groups, no significant differences were found in the other production measurements. Bodyweight gain was larger in the four‐hen cages than the six‐hen cages (P < 0.01). In conclusion, behavior was not restricted in the furnished cages, but activity and bodyweight gain were affected by group size (density) rather than cage design. Hereafter, the studies on suitable density in each cage design, using young layers, are required.     

Expression profiling of mouse placental lactogen II and its correlative genes using a cDNA microarray analysis in the developmental mouse placenta

The placenta is a highly differentiated organ essential for embryonic growth and development. In order to search for key molecules that are associated with mouse placental lactogen II (mPL-II) gene expression, we applied mouse cDNA microarray analysis to RNAs extracted from placentae on days 10, 12, 14, 16 and 18 of pregnancy. Changes in gene expression were categorized between days 10 and 12, 12 and 14, 14 and 16 and 16 and 18 of pregnancy. After microarray analysis, which had a minimum detectable fold change for differential expression of 2, we selected 10 genes, Apoa2, Apoc2, Ceacam14, Creg1, Fmo1, Igf2, Slc2a1, Spink3, Spi1-1 and Tpbpa, exhibiting a expression pattern similar to the mPL-II gene. Furthermore, we performed real-time PCR analysis and in situ hybridization (ISH) to find correlative expression genes for the mPL-II gene. From these results, we identified a resemblance in gene expression between mPL-II and Igf2 and selected these genes for performance of double-fluorescence immunohistochemical staining. We colocalized these proteins in labyrinthine trophoblast cells. These results strongly suggest that the expression of mPL-II and Igf2 is highly related to placental development in mice. This large-scale identification of genes regulated during placentogenesis assists in further elucidation of the molecular basis of extraembryonic development and function.     

Detection of a major QTL related to smut disease resistance inherited from a Japanese wild sugarcane using GRAS-Di technology

Smut disease of sugarcane causes considerable yield losses and the use of resistant varieties is the best control practice. Our group identified a Japanese wild sugarcane with highly smut disease resistance named ‘Iriomote8’. In this study, we conducted QTL analysis for smut disease resistance using a mapping population derived from a resistant variety ‘Yaenoushie’, in which resistance is inherited from ‘Iriomote8’. We identified 4813 non-redundant markers using GRAS-Di technology and developed a linkage map of mapping parents. We evaluated smut disease resistance of the mapping population by the inoculation test. Consequently, a large number of clones did not show the disease symptoms and the distribution of smut disease incidence tended to be “L shaped”. Composite interval mapping detected an identical QTL for indices of smut disease incidence with a markedly high LOD score (26.6~45.6) at the end of linkage group 8 of ‘Yaenoushie’. This QTL explained approximately 50% of the cases of smut disease incidence. In the mapping population, there were no correlations between the indices of smut disease incidence and other agronomic traits. In conclusion, this QTL could be used for marker-assisted selection to significantly improve smut disease resistance without negative effects on other agronomic traits.     

Overexpression of the Barley Nicotianamine Synthase Gene HvNAS1 Increases Iron and Zinc Concentrations in Rice Grains

In humans, iron (Fe) and zinc (Zn) deficiencies result in major worldwide health problems. Transgenic technologies to produce Fe- and Zn-biofortified rice varieties offer a promising potential solution. Nicotianamine, the precursor of phytosiderophores, chelates Fe²⁺ and Zn²⁺ and plays an important role in transporting these metals to both vegetative and reproductive organs within the plant. Our objective was to increase Fe and Zn contents in rice grains by overexpressing the barley nicotianamine synthase gene HvNAS1. HvNAS1-overexpressing transgenic rice showed increased HvNAS1 expression and subsequent increases in endogenous nicotianamine and phytosiderophore content in shoots, roots, and seeds. Fe and Zn concentrations in polished T₁ seeds from transgenic plants increased more than three and twofold, respectively; Fe and Zn concentrations also increased in both polished and brown T₂ seeds. These results suggest that the overproduction of nicotianamine enhances the translocation of Fe and Zn into rice grains.