Leucobacter populi sp. nov. isolated from a symptomatic bark of Populus × euramericana canker.

A Gram-stain positive, aerobic, non-motile, rod-shaped, oxidase-negative and catalase-positive bacterial strain, designated 06C10-3-11T, was isolated from the symptomatic bark of a Populus × euramericana canker. Growth occurred at 10-45 °C (optimum, 30 °C), pH 6-11 (optimum, pH 7.0-8.0), 0-7 % (w/v) NaCl (optimum, 0-1 %) and in the presence of 20 mM Cr (VI). The major fatty acids (≥10 %) of the novel strain were identified as anteiso-C15:0, anteiso-C17:0 and iso-C16:0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipid, glycolipid and two unknown lipids. The strain contained the respiratory quinone MK-10 (71 %) as a major component and MK-11 (29 %) in lesser amounts. The cell wall amino acids were 2,4-diaminobutyric acid, alanine, glutamic acid and glycine. The genomic DNA G+C content of the type strain was 69.8 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that strain 06C10-3-11T belongs to the genus Leucobacter, showing the highest 16S rRNA gene sequence similarities with Leucobacter celer NAL101T (96.19 %), 'Leucobacter kyeonggiensis' F3-P9T (96.18 %), Leucobacter denitrificans M1T8B10T (96.10 %) and Leucobacter aridicollis CIP 108388T (96.06 %). The DNA G+C content of strain 06C10-3-11T was 69.8 mol%. Based on the molecular data and physiological and biochemical characteristics, strain 06C10-3-11T is considered to represent a novel species of the genus Leucobacter, for which the name Leucobacterpopuli sp. nov. is proposed. The type strain is 06C10-3-11T (= CFCC 12199T = KCTC 39685T).

Invasion Genetics of Woolly Apple Aphid (Hemiptera: Aphididae) in China.

In China, the woolly apple aphid, Eriosoma lanigerum (Hausmann), was first detected as an invasive species during the 1910s to 1930s, restricted to Shandong, Liaoning, and Yunnan Provinces. However, since the 1990s, the pest has spread into many other areas of China. To determine the possible spread routes of the recently established populations, the genetic diversity and genetic structure of 24 populations in 10 provinces were analyzed using eight microsatellite loci. Analyses using STRUCTURE software identified two genetic clusters overall. Three populations from Yunnan and Xinjiang consisted of individuals originating from a single cluster. Nineteen populations from eight northern provinces consisted only of individuals from another cluster, which formed a single large and panmictic population, resembling a distinct "supercolony" in Northern China. The other two populations from Yunnan consisted of individuals from both clusters. The possible routes of spread of the recently established populations of E. lanigerum in China were revealed as follows: 1) the populations in Northern China (including these from Henan, Hebei, Shanxi, Shannxi, Jiangsu, and Gansu) may have been introduced from Shandong or Liaoning Provinces; 2) the populations in Yunnan consisted of an early-established population and a population introduced secondarily from Shandong or neighboring areas, indicating that the population in Yunnan has at least two sources; and 3) the recently established populations of E. lanigerum in Xinjiang might not have been introduced from the "supercolony" in Northern China. Knowledge of these routes of spread is useful for avoiding further dissemination and/or additional introductions.

Chemical characteristics of normal, woolly apple aphid-damaged, and mechanically damaged twigs of six apple cultivars, measured in autumn wood.

Chemical characteristics of normal, woolly apple aphid-damaged, and mechanically damaged twigs of six apple cultivars: Red Fuji, Golden Delicious, Qinguan, Zhaojin 108, Starkrimson, and Red General, were examined in autumn wood to provide abetter understanding of factors related to cultivar resistance to the woolly apple aphid, Eriosoma lanigerum (Hausmann). Chemical measures examined included soluble sugars, soluble proteins and amino acids, total phenolics, and polyphenol oxidase (that enhances the resistance of plants to insects) and superoxide dismutase, peroxidase, and catalase (that degrade waste products in plants). Soluble sugar, protein, and amino acid contents in normal (undamaged) twigs of Red Fuji, aphid-susceptible cultivar, were higher than in mechanically damaged and aphid-damaged twigs. Total phenolic compounds, an important group of defensive compounds against aphids, increased by 30.5 and 6.0% in mechanically damaged twigs of Qinguan and Zhaojin 108, respectively, and decreased by 21.7 and 16.1% in aphid-damaged twigs of Red Fuji and Red General, respectively. Compared with normal twigs, in aphid-damaged twigs, superoxide dismutase, peroxidase, and polyphenol activity all decreased in Red Fuji. The resistance of some apple cultivars to woolly apple aphid during the growth of autumn shoots was related to several of the physiological indices we monitored. The thin epidermis of callus tissue over healed wounds showed increased susceptibility to the attack by woolly apple aphid. Apple cultivar Qinguan with the highest level of resistance to woolly apple aphid in autumn had increased in amino acid, total phenolic compound levels, and enzyme activity after aphid feeding.

A luminescent Eu(III) complex based on 2-(4', 4', 4'-trifluoro-1', 3'-dioxobutyl)-dibenzothiophene for light-emitting diodes.

Complex Eu(dbt)(3)(phen) (Hdbt=2-(4', 4', 4'-trifluoro-1', 3'-dioxobutyl)-dibenzothiophene, phen=1,10-phenanthroline) was synthesized. The complex emits red luminescence, characteristic of the (5)D(0)-->(7)F(J) (J=0-4) emission bands of Eu(3+) under near ultraviolet. A red conversion light-emitting diode (LED) device was fabricated by coating complex onto InGaN-based-LED chip that emits 395nm ultraviolet light. When the mass ratio of the red phosphor to the silicone is 1:25, the LED device's CIE chromaticity coordinates are x=0.5835, y=0.2857, and the luminescence efficiency is 1.29 lm/w. All the results show that this europium complex may act as a red component in fabrication of white LEDs with high color-rendering index.