<Emphasis Type="Italic">Verticillium tricorpus</Emphasis> causing lettuce wilt in Japan differs genetically from California lettuce isolates

In January 2002, Verticillium wilt of lettuce (Lactuca sativa L.) caused by Verticillium tricorpus occurred in upland paddy fields in Hyogo Prefecture for the first time in Japan. This fungal species was first isolated from lettuce in California, USA. In the present study, the genetic relationships between the American and Japanese isolates of V. tricorpus from lettuce were analyzed to determine whether the pathogen could have migrated to Japan from the USA, the major lettuce-seed supplier for Japan. Nucleotide sequences of the rDNA internal transcribed spacer regions, as well as the genes coding for translation elongation factor 1-alpha and RNA polymerase II were compared among American and Japanese V. tricorpus isolates from lettuce. The Japanese isolates of V. tricorpus were distinct from the American. Random amplified polymorphic DNA analyses also supported this conclusion. These results demonstrated that Verticillium wilt on lettuce caused by V. tricorpus in Japan was not related to the isolates causing the disease in California.     

Specific and non-specific adsorption of inorganic ions

The authors reported that the relative bonding strength between ligand of soil colloid surface and cations could be obtained easily by the measurement of MCSA, and that the MCSA corresponded to the constant of Langmuir's adsorption isotherm equation.

The relative bonding strength of cations with respect to kaolinitic soil clay at pH 6 was, Cr³⁺>Fe³⁺, Al³⁺>Ga⁸⁺>Cu⁸⁺>Pb²⁺>Y³⁺, La³⁺>Mn²⁺>Ni²⁺, Co²⁺> Zn²⁺>Sr²⁺, Mg²⁺>NH⁴⁺, K⁺, and with respect to colloid with humus coating, Y³⁺, La³⁺>Pb²⁺>Cu²⁺, and the other orders were same.

The solubility of cations in soil colloid aqueous dispersion system was calculated from the values of MCSAs, and considered as follows, Y³⁺, La³⁺, Cu³⁺, Pb³⁺, Mn²⁺, Ni²⁺, CO²⁺: concentration in soil solution and soil geochemical mobility may be regulated by the specific adsorption reaction, Zn²⁺, Mg²⁺, Sr²⁺, K⁺, NH⁴⁺: concentration in soil solution and soil geochemical mobility may be regulated by the non-specific adsorption reaction, but at neutral to alkaline condition, Zn²⁺ and Mg²⁺ may specifically adsorb on soil, clays, Fe³⁺, Cr³⁺, Al³⁺, Ga³⁺: concentration in soil solution and soil geochemical mobility may be regulated by the solubility of their oxide hydrates.     

Factors Affecting Microbial Biomass and Dehydrogenasc Activity in Apple Orchard Soils with Heavy Metal Accumulation

The size of the microbial biomass and dehydrogenase activity were measured in air-dried and rewetted apple orchard surface soils with accumulation of Cu, Pb, and As due to the application of Bordeaux mixtures and lead arsenate. The largest amounts of total Cu, Pb, and As found in the soils used were 1,108, 1,271, and 209 mg kg^-1 soil, respectively. The amounts of 0.1 M HCl-extractable heavy metals were strongly correlated with the total amounts, while those of 0.1 M CaCl₂-extractable heavy metals, except for As, increased significantly with decreasing soil pH. The amounts of microbial biomass C and N, expressed on a soil organic C and total N basis, respectively, were each negatively correlated with the amounts of total and 0.1 M HCl-extractable Cu. On the other hand, the dehydrogenase activity was not affected by the amounts of total and 0.1 M HCl-extractable heavy metals, and was negatively correlated with the amount of 0.1 M CaCl₂-extractable Cu and positively with the soil pH. Higher significant correlations were observed when the dehydrogenase activity was calculated per unit of soil organic C. Thus the microbial biomass was adversely affected by the slightly soluble fractions of Cu accumulated in apple orchard soils, whereas the dehydrogenase activity was affected by the water-soluble and exchangeable Cu of which amount depended on the soil pH. It is suggested that the microbial biomass and dehydrogenase activity expressed on a soil organic matter basis could become useful indicators for assessing the effects of heavy metals on the size and activity of the microbial biomass in soils differing in organic matter contents.     

Soil degradation during the period 1967–1995 in Bangladesh

Long-term changes in carbon and nitrogen storage in the top 100 em layers of soils from different physiographic units in Bangladesh were evaluated using 460 soil samples from 43 profiles collected in 1967 and 1994/95. The study area consisted of ten physiographic units, viz.: Old Himalayan Piedmont Plain (OHP), Tista Floodplain (TF), Barind Tract (BT), Ganges Floodplain (GF), Madhupur Tract (MT), Brahmaputra Floodplain (BF), Meghna River and Estuarine Floodplain (MF), Surma-Kushiyara Floodplain (SKF), Northern and Eastern Piedmont Plain (NEP), and Chittagong Coastal Plain (CCP).

During the period 1967–1995, mean values of soil carbon and nitrogen declined by 16.2 t C ha^-1 and 1.38 t N ha^-1 in Bangladesh. The total carbon and nitrogen budgets showed a fall of 42.8 × 10⁶ t C and 3.36 × 10⁶ t N within the 27 y period in Bangladesh. All the physiographic units showed a decline in carbon and nitrogen contents except for BT which showed an increase of 3.76 t C ha^-1 and 0.77 t N ha^-1 for these elements. MT showed the highest decline in carbon (30.5 t C ha^-1) and nitrogen (3.25 t N ha^-1). The lowest decline in carbon was observed in SKF (7.18 t C ha^-1) while the same applied to nitrogen in GF (0.50 t N ha^-1). The other physiographic units showed a moderate decline in the contents of these elements.

Based on the land area occupied by the sampled soil series of each physiographic unit, GF showed the highest decline of 13.7×10⁶ t C and a moderate decline of 0.52 × 10⁶ t N. Decrease in the carbon level for BF was moderate (9.31 × 10⁶ t C) but the decline in the nitrogen level was the highest (0.95 × 10⁶ t N). Decrease in the amount of carbon and nitrogen stored for the other physiographic units was: OHP (0.67 × 10⁶ t C, 0.03 × 10⁶ t N), TF (2.54 × 10⁶ t C, 0.25 × 10⁶ t N), MT (4.28 × 10⁶ t C, 0.45 × 10⁶ t N), MF (6.06 × 10⁶ t C, 0.61 × 10⁶ t N), SKF (2.87×10⁶ t C, 0.24×10⁶ t N), NEP (2.68×10⁶ t C, 0.22×10⁶ t N), and CCP (0.81 × 10⁶ t C, 0.11 × 10⁶ t N). Increase in carbon and nitrogen contents was only observed in BT (0.08 × 10⁶ t C, 0.02 × 10⁶ t N).     

Comparative analysis of the relationship between Cs and K in soil and plant parts toward control of Cs accumulation in rice

The effect of soil exchangeable potassium (K) and cesium (Cs) levels on Cs uptake and accumulation in different parts of rice (Oryza sativa L.) plants were examined using paddy soils with diverse exchangeable K and Cs in pot experiments. Aboveground Cs uptake decreased with higher exchangeable K and was linearly correlated with exchangeable Cs/K ratios, indicating competitive absorption of these elements by roots. Variation in Cs concentration in brown rice among soils was also related to the exchangeable Cs/K ratio. The exchangeable Cs/K ratio was positively reflected in the Cs/K concentration ratio in each plant part, with a specific slope, suggesting that Cs transport was coordinated with K transport and that there were regulated discriminations of Cs against K in the translocation process among parts. The Cs/K ratio was higher in brown rice and dead leaves than in active leaves, stems and husks. The distribution of Cs accumulation in brown rice was 14.5% on average, but it was variable and negatively related to K concentration in the stem. The Cs distribution in aboveground plant parts also decreased with higher K concentration in the root. These results imply the importance of the competitiveness with K in the root absorption and translocation of Cs within the plant. Based on the observed relationship between Cs and K, effective K management and other measures to control Cs accumulation in plant parts are discussed.     

Comparison of the activity of non‐steroidal ecdysone agonists between dipteran and lepidopteran insects,using cell‐based EcR reporter assays

BACKGROUND: Diacylhydrazine (DAH) analogues have been developed successfully as a new group of insect growth regulators, called ecdysone agonists or moulting accelerating compounds. These DAHs have been shown to manifest their toxicity via interaction with the ecdysone receptor (EcR) in susceptible insects, as does the natural insect moulting hormone 20‐hydroxyecdysone (20E). A notable feature is their high activity and specificity, particularly against lepidopteran insects, raising the question as to whether non‐lepidopteran‐specific analogues can be isolated. However, for the discovery of ecdysone agonists that target other important insect groups such as Diptera, efficient screening systems that are based on the activation of the EcR are needed. RESULTS: In this study, a dipteran‐specific reporter‐based screening system with transfected S2 cells of Drosophila melanogaster Meig. was developed in order to discover and evaluate compounds that have ecdysone agonistic or antagonistic activity. A library of non‐steroidal ecdysone agonists containing different mother structures with DAH and other related analogues such as acylaminoketone (AAK) and tetrahydroquinoline (THQ) was tested. None of the compounds tested was as active as 20E. This is in contrast to the very high activity of several DAH and AAK congeners in lepidopteran cells (Bombyx mori L.‐derived Bm5 cells). The latter agrees with a successful docking of a DAH, tebufenozide, in the binding pocket of the lepidopteran EcR (B. mori), while this was not the case with the dipteran EcR (D. melanogaster). Of note was the identification of two THQ compounds with activity in S2 but not in Bm5 cells. Although marked differences in activity exist with respect to the activation of EcR between dipterans and lepidopterans, there exists a positive correlation (R = 0.724) between the pLC₅₀ values in S2 and Bm5 cells. In addition, it was found through protein modelling that a second lobe was present in the ligand‐binding pocket of lepidopteran BmEcR but was lacking in the dipteran DmEcR protein, suggesting that this difference in structure of the binding pocket is a major factor for preferential activation of the lepidopteran over the dipteran receptors by DAH ligands. CONCLUSIONS: The present study confirmed the marked specificity of DAH and AAK analogues towards EcRs from lepidopteran insects. THQ compounds did not show this specificity, indicating that dipteran‐specific ecdysone‐agonist‐based insecticides based on the THQ mother structure can be developed. The differences in activity of ecdysone agonists in dipteran and lepidopteran ecdysone‐reporter‐based screening systems are discussed. Copyright © 2010 Society of Chemical Industry     

Evaluation of yield performance in rice near-isogenic lines with increased spikelet number

Rice yield potential is determined by the balance between sink size and source capacity. To clarify the factors that limit yield in temperate japonica cultivars, we compared the yield performance of Sasanishiki, a temperate japonica cultivar, with those of three near-isogenic lines (NILs) of Sasanishiki with introgression of quantitative trait loci (QTL) derived from a high-yielding indica cultivar, Habataki: qSBN1, which increases the number of secondary rachis branches; qPBN6, which increases the number of primary rachis branches; and a pyramid line that combines these two QTLs. NIL (SBN1), NIL (PBN6), and NIL (SBN1 + PBN6) produced 28–37%, 9–16%, and 62–65% more spikelets per panicle than Sasanishiki, respectively. However, the NILs with increased spikelet number per panicle did not increase grain yield significantly, because compensation is taken place among different yield components. The pyramid line nevertheless had 4–12% higher yield than Sasanishiki due to greater translocation of carbohydrates from stem to panicle. There was no difference in carbohydrate accumulation before heading or in biomass production among Sasanishiki and the three NILs. The results indicate that increasing sink size does not substantially improve yield in Sasanishiki, which lacks sufficient substrate supply to fully satisfy the increased sink demand that results from the spikelet-number QTLs.     

Efficient bioethanol production from water hyacinth Eichhornia crassipes by both preparation of the saccharified solution and selection of fermenting yeasts

Although water hyacinth is an adventive aquatic plant that threatens the Japanese ecosystem, its high growth rate may be a benefit in terms of its potential as a raw material for the production of bioethanol. In our study, water hyacinth was saccharified with 3?% (v/v) sulfuric acid and subjected to cellulase treatments to determine optimum bioethanol production conditions. The original saccharified solution yielded both glucose at 5.3?±?0.2?g/l and reducing sugars at 9.7?±?0.1?g/l. Concentration of the saccharified solution under vacuum at 70?°C yielded both glucose at 21.5?±?2.9?g/l and reducing sugars at 33.3?±?2.1?g/l. An aquatic yeast Saccharomyces cerevisiae TY2 produced ethanol at 9.6?±?1.1?g/l from the concentrated saccharified solution. In comparison, Ogawa et al. (Afr J Microbiol Res 2:110?C113, 2008) reported that this yeast produced 0.90?g/l and that the production of bioethanol was about 11.2-fold lower than that obtained in our study. These results suggest that refinement of the saccharification process and application of the selected yeast could improve the efficiency of obtaining bioethanol from the water hyacinth.     

Stereochemical and chiral aspects in the synthesis of 3-(2,2- dihalovinyl)-2,2-dimethylcyclopropanecarboxylic acids

The synthesis of (1RS)-cis,trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid by dehydrohalogenation of 4,6,6,6-tetrahalohexanoates has been modified to produce stereo-selectively the cis-isomer. A new stereospecific synthesis of cis-3-(2,2-dihalovinyl)-2,2-dimethylcyclopropanecarboxylic acids using a bicyclic lactone and its extension to the preparation of the optically active (1R)-cis acid are described.