Variation in Doubled Haploid Plants of Wheat Obtained through Wheat (Triticum aestivum) × Maize (Zea mays) Crosses

Variation was investigated in 110 doubled haploid (DH) lines of wheat derived from wheat × maize crosses. Field observation revealed visible variations in 15 DH2 lines such as extreme dwarfism, low seed fertility, alteration of spike type and stripes. Six agronomic traits, i.e., heading date, spike number/ plant, culm length, spike length, seed fertility and grain weight were statistically analyzed in the DH2 and DH3 generations. Out of the 88 DH2 lines/DH3 groups, 26 %/64 % showed significant differences from the parental variety in the means of one or more traits. Ranges of the DH3 lines were larger than those of the DH2 lines, except for spike number/plant. Furthermore, analyses of variance within and between DH lines showed the presence of heterogeneity/heterozygosity in the DH2 lines/plants. These results indicated the occurrence of gametoclonal variation in the DH lines. It is considered that most of the variations detected were due to the colchicine treatment rather than to the 2,4-D treatment or in vitro culture.     

Allelopathic potential and an allelopathic substance in mango leaves

The present study was aimed to determine the allelopathic potential of mango (Mangifera indica L.) leaves and to identify allelopathic substances in the leaves. The aqueous methanol extracts of mango leaves inhibited seedling growth of garden cress, radish, rapeseed, foxtail fescue and crabgrass, and the inhibitory effects increased with the increasing extract concentration, suggesting that mango leaves may contain allelopathic substances. The extract was then purified by several chromatographic runs through a bioassay-directed fractionation, and an growth inhibitory substance was isolated and identified by spectral data as methyl-3,4,5-trihydroxybenzoate (methyl gallate). Methyl gallate at the concentration of 10 mM inhibited 98.6% and 99.8% of root and shoot growth of garden cress relative to the control, respectively, and 94.4% and 49.3% of those of foxtail fescue, respectively. The concentrations of methyl gallate required for 50% growth inhibition (I₅₀) on garden cress roots and shoots were 3.9 and 3.3 mM, and those on foxtail fescue roots and shoots were 1.5 and 9.5 mM, respectively. It is the first report of an allelopathic substance in mango leaves and allelopathic activity of methyl gallate. Therefore, the mango leaves may have potential as a soil additive material for the weed management options.     

Brachyspira pilosicoli isolated from two beagles and one mongrel in Japan

The feces, colonic contents, and colonic mucosa from two beagles and a mongrel with and without mucohemorrhagic diarrhea were anaerobically cultured and after 72 hr, lucent and rough colonies with weak beta-hemolysis were observed. Small spirochetes with one or two loose waves in the colonies were observed under a phase contrast microscope and the spirochete cells sometimes aggregated. The 16SrDNA sequencing results demonstrated that the canine isolates were B. pilosicoli and the base alignments registered in DDBJ. This is the first report concerning the isolation of B. pilosicoli from dogs in Japan.     

Element-selective single atom imaging

Electron energy-loss spectroscopy (EELS) is widely used to identify elemental compositions of materials studied by microscopy. We demonstrate that the sensitivity and spatial resolution of EELS can be extended to the single-atom limit. A chemical map for gadolinium (Gd) clearly reveals the distribution of Gd atoms inside a single chain of metallofullerene molecules (Gd@C82) generated within a single-wall carbon nanotube. This characterization technique thus provides the "eyes" to see and identify individual atoms in nanostructures. It is likely to find broad application in nanoscale science and technology research.     

Imaging of single organic molecules in motion

High-resolution transmission electron microscopy revealed nearly atomically precise images of stepping conformational change and translational motion of single hydrocarbon molecules confined in carbon nanotubes. One or two C12 or C22 alkyl chains were tethered to a carborane end group and then embedded in the nanotubes. Images of the hydrocarbon chains interacting with each other and with a graphitic surface provide information on three-dimensional structures and dynamic molecular interactions that cannot be obtained by other analytical methods.     

Pathogenic races of soybean rust Phakopsora pachyrhizi collected in Tsukuba and vicinity in Ibaraki,Japan

Six races were identified among 26 single-lesion isolates of Phakopsora pachyrhizi from rust-infected leaves of nine samples of cultivated soybean and one sample of the wild host plant kudzu (Pueraria lobata) collected in Tsukuba and vicinity in Ibaraki, Central Honshu, Japan. Six races were detected on soybean cultivars and four races on kudzu. When two or more isolates obtained from the same samples were examined, the isolates were different races except from two samples. These results indicate that two or more races may be distributed on the same soybean cultivar and that the same races share soybean and kudzu hosts.