Variations of the vascular bundle system in Asian rice cultivars

Summary The capacity of vascular bundle system transporting assimilates from source to sink is one of the limiting factors for rice (Oryza sativa L.) yield. Genetic variation in vascular bundle system should be investigated for improvement of transporting efficiency. A total of 531 Asian rice cultivars were studied for vascular bundles in the peduncle and its relation to spike morphology. A few difference was detected for the number of primary rachis branches of the spike among the cultivars from various countries. However, the number of vascular bundles significantly differed among the cultivars; those from Nepal, Bangladesh and India bore more vascular bundles than those from Japan. Therefore, the ratio of vascular bundles to rachis branches (V/R ratio) was nearly 1.0 in cultivars from Japan, while those from Nepal, Bangladesh and India ranged from 1.3 to 2.2. Chinese and Indonesian cultivars incuded two types of high and low V/R ratios. Cultivars with high V/R ratio showed positive reactions to the phenol solution, while those with low V/R ratio were negative reactions, suggesting that the former cultivars are of Indica type and the latter of Japonica type. It was concluded that the relationship between vascular bundles and rachis branches differentiated among the ecotypes of Asian cultivated rice.     

Suppression of aging in mice by the hormone Klotho

A defect in Klotho gene expression in mice accelerates the degeneration of multiple age-sensitive traits. Here, we show that overexpression of Klotho in mice extends life span. Klotho protein functions as a circulating hormone that binds to a cell-surface receptor and represses intracellular signals of insulin and insulin-like growth factor 1 (IGF1), an evolutionarily conserved mechanism for extending life span. Alleviation of aging-like phenotypes in Klotho-deficient mice was observed by perturbing insulin and IGF1 signaling, suggesting that Klotho-mediated inhibition of insulin and IGF1 signaling contributes to its anti-aging properties. Klotho protein may function as an anti-aging hormone in mammals.     

Cytologic variants of γδ T cell lymphoma in cattle

Two cytologic variants of γδ T cell lymphoma are described. Case 1 represented a giant cell variant found in a 5-year-old Holstein cow, which had large tumor masses in the pelvic cavity. This variant consisted of very large lymphoid cells with round to oval nuclei, medium-sized nucleoli and abundant cytoplasm. Case 2 was an aborted 7-month-old female Holstein fetus, which represented an immature cell variant. Most of the neoplastic lesions were located in the skin and pleural and peritoneal submesothelial tissues. The neoplastic tissues were composed of homogeneous growth of lymphoma cells characterized by inconspicuous nucleoli and finely dispersed chromatin. Both cases demonstrated CD3, CD8 and WC1 immunoreactivity. The current study revealed that there are 4 cytologic variants (common, giant cell, hypergranular and immature cell) in bovine γδ T cell lymphomas.     

Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin

Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.     

A scheme for mass propagation of Lilium in vitro

A mass propagation scheme for Lilium plants using a shake culture technique has been developed. According to the scheme, about 1.2 × 10¹⁰ of L. speciosum or 3.2 × 10¹² of L. auratum bulbs can theoretically be obtained in one year from one medium sized bulb. The scheme involves 4 steps: (1) establishment of aseptic production of bulblets; (2) the stimulation of bulb-scale production by high K and their rapid growth in shake cultures; (3) bulblet production; (4) the establishment of bulblets in soil.     

Effects of applied gibberellins and uniconazole-P on gravitropism and xylem formation in horizontally positionedFraxinus mandshurica seedlings

The present study deals with the effects of gibberellins (GA₃ GA₄) and uniconazole-P, an inhibitor of gibberellin biosynthesis, on negative gravitropism and xylem formation in the stems of horizontally positioned, 2-year-oldFraxinus mandshurica Rupr. var.japonica Maxim. seedlings. Each growth regulator (100 g) dissolved in 5 l acetone (50%) was applied to the basal node of the current shoot on May 24, 1995. The same treatment was repeated five times weekly until June 28. Five seedlings were used for each treatment. The seedlings were positioned horizontally 24h after the first application on May 25. Within 5 weeks the horizontal stem of control and GA-treated seedlings exhibited negative gravitropism. In contrast, the application of uniconazole-P inhibited negative gravitropic stem bending. The application of GAs increased the number of gelatinous fibers having thickened cell walls on the upper side of stems. The uniconazole-P application decreased xylem cell formation but did not inhibit the formation of gelatinous fibers. These results indicate that not only the differentiation of gelatinous fibers but also xylem increment is important in the negative gravitropism of horizontally positionedF. mandshurica seedlings. These results also suggest that GAs may be involved in xylem cell :formation rather than the differentiation of gelatinous fibers in this species.Part of this research was reported at the 23rd annual meeting of the Plant Growth Regulation Society of America, Calgary, Canada, July 1996     

Ultraviolet microspectrophotometric investigation of the distribution of lignin in Prunus jamasakura differentiated on a three-dimensional clinostat

To examine the effect of gravity on lignin content and deposition in plant cells, we used ultraviolet (UV) microspectrophotometry and chemical methods to investigate the secondary xylem of Prunus jamasakura grown on a three-dimensional (3D) clinostat, which simulates microgravity. The stem of the 3D-clinostat specimens elongated with bending and the width of their secondary phloem increased. The UV absorbance of the 3D-clinostat specimens at 278 nm was higher than that of the control specimens, which were grown on the ground, in the wood fiber cell corner middle lamella, compound middle lamella, and fiber secondary wall; the UV absorbance in the vessel secondary wall did not differ between the specimens. The lignin content in the stem, including the bark, of the 3D-clinostat specimens, as determined using an acetyl bromide method, was less than that of the control specimens. In the specimens that differentiated on a 3D clinostat, the amount of lignin in the wood fibers increased, while the proportion of the lignified xylem in the stem decreased relative to control values.     

Volatile organic compounds from wood and their influences on museum artifact materials I. Differences in wood species and analyses of causal substances of deterioration

Wood is generally used as the interior material in museum storage rooms. Recently, however, the effects of volatile organic compounds (VOCs) from wood on artifacts has become a topic of great concern. The VOCs from four species of wood (western red cedar, spruce, kiri, and sugi) and their effects on artifact materials (two types of metal, seven types of pigment) were investigated using a deterioration-accelerating test, gas chromatography-mass spectrometry, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The results suggested that the influences on artifact materials varied greatly with wood species, and depended on specific components such as hinokitiol or acetic acid rather than the amount of total volatile organic compounds (TVOCs). It is a very serious problem that of the four species of wood, western red cedar (rich in hinokitiol), which has been recommended as an interior material for museum storage rooms, showed the heaviest deterioration on metal samples, and only this type of wood discolored enpaku (white lead) and rokushou (malachite, verdigris). In such storage rooms, museum artifacts should be carefully monitored. When selecting an interior material for a storage room or studying methods of preventing deterioration, it is very important to consider fully the characteristics of wood VOCs, not only the amount of TVOC.Part of this paper was presented at the 24th (Tokyo, June 2002) and 25th (Kyoto, June 2003) Annual Meeting of the Japan Society for the Conservation of Cultural Property     

Phylogeography of the Japanese eight-barbel loach <Emphasis Type="Italic">Lefua echigonia</Emphasis> from the Yamagata area of the Tohoku district,Japan

The Japanese eight-barbel loach Lefua echigonia, which is a freshwater fish native to Japan, is distributed from the Tohoku to Kinki districts and is divided into six regional populations according to mtDNA analysis. In this study, we investigated L. echigonia collected from several locations in Yamagata Prefecture and neighboring prefectures using mtDNA control region sequences and confirmed the spatial distribution pattern among the new regional population (Yamagata population). The new population was limited to the Mogami river system in the inland area of Yamagata Prefecture and is distinguished from other regional populations by high sequence divergences.