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331.
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333.
Verification of Drainage Sterilization System Uses Low-Voltage Pulsed Electric Field in a Prawn Farm
It is necessary to take measures against infectious diseases in the Southeast Asian prawn farming industry. In giant tiger prawn (Penaeus monodon) aquaculture, diseases caused by viruses such as white spot syndrome virus (WSSV) and bacteria such as Vibrio have become a menace. Appropriate treatments of prawn culture pond's waters are advocated for preventing and controlling pathogens. The purpose of this study was to conduct an antimicrobial water treatment using a low-voltage pulsed electric field sterilization. Here we prepared a mechanical low-voltage pulsed electric field system with copper wire coiling around a titanium ring. The viability of WSSV in seawater was examined by prawn infectivity experiments. We inoculated healthy prawns (approximately 10-15 g) with the WSSV master sample that passed 0-3 times through the system. WSSV infection in prawns decreased according to the number of passes through the system. Healthy prawns survived for〉 10 days without feeding, where as prawns inoculated with the WSSV master sample showed symptoms of white spot and died in about 4 days. Two-thirds of the prawns inoculated with the WSSV master sample that was passed once through the system developed WSSV symptoms and were polymerase chain reaction (PCR) positive. However, no symptoms were observed and prawns were PCR negative when the WSSV master sample was passed three times through the system. Based on these results, we purpose that a low-voltage pulsed electric field system will serve as an efficient pond drainage sterilization system and will replace conventional treatments using chemicals such as sodium hypochlorite. 相似文献
334.
Hiroki Nakayama Tsukasa Nagamine Nagao Hayashi 《Genetic Resources and Crop Evolution》2005,52(7):863-868
To clarify the geographic variation and isolate specificity in blast resistance, 20 cultivars of foxtail millet (Setaria italica (L.) P. Beauv.) originating from Eurasia were examined for their resistance using 11 Japanese Setaria isolates of blast fungus. Cultivars from the countries east of Pakistan generally showed resistance to most of the 11 fungus
isolates, whereas those from the countries west of Afghanistan indicated higher susceptibility. The origin of this geographical
regularity was discussed in relation to the deficiency or specificity of relevant resistance gene(s). No identical reaction
pattern was observed among cultivars, indicating their highly distinctive isolate specificity. The virulence of isolates was
also diverse, since only 2 out of 10 virulent isolates were identical for their reaction patterns. Preliminary genetic analysis
of blast resistance to four fungus isolates suggests that they are governed by more than two dominant genes. 相似文献
335.
Studies of the constituents of Uruguayan propolis 总被引:4,自引:0,他引:4
Kumazawa S Hayashi K Kajiya K Ishii T Hamasaka T Nakayama T 《Journal of agricultural and food chemistry》2002,50(17):4777-4782
Eighteen flavonoids including two new compounds, four aromatic carboxylic acids, and eleven phenolic acid esters including one new compound were isolated and identified from the ethyl acetate soluble fraction of the 70% ethanol extract of Uruguayan propolis. The new compounds were elucidated as pinobanksin 3-(2-methyl)butyrate (1; recently reported in Usia, T.; Banskota, A. H.; Tezuka, Y.; Midorikawa, K.; Matsushige, K.; Kadota, S. J. Nat. Prod. 2002, 65, 673-676) pinobanksin 3-isobutyrate (2), and 2-methyl-2-butenyl ferulate (24). The constituents isolated from Uruguayan propolis in this study were similar to those of propolis of European and Chinese origin. Thus, it is suggested that the Uruguayan propolis has a plant origin similar to those of propolis from Europe and China. 相似文献
336.
The assembly of higher order chromatin structures has been linked to the covalent modifications of histone tails. We provide in vivo evidence that lysine 9 of histone H3 (H3 Lys9) is preferentially methylated by the Clr4 protein at heterochromatin-associated regions in fission yeast. Both the conserved chromo- and SET domains of Clr4 are required for H3 Lys9 methylation in vivo. Localization of Swi6, a homolog of Drosophila HP1, to heterochomatic regions is dependent on H3 Lys9 methylation. Moreover, an H3-specific deacetylase Clr3 and a beta-propeller domain protein Rik1 are required for H3 Lys9 methylation by Clr4 and Swi6 localization. These data define a conserved pathway wherein sequential histone modifications establish a "histone code" essential for the epigenetic inheritance of heterochromatin assembly. 相似文献
337.
A general chemical strategy has been developed whereby antibody combining sites can be selectively derivatized with natural or synthetic molecules, such as catalytic groups, drugs, metals, or reporter molecules. Cleavable affinity labels were used to selectively introduce a thiol into the combining site of the immunoglobulin A MOPC 315. This thiol acted both as a nucleophile to accelerate ester thiolysis 60,000-fold and as a handle for selectively derivatizing the antibody with additional functional groups. For example, derivatization of the antibody with a fluorophore made possible a direct spectroscopic assay of antibody-ligand complexation. This chemistry should not only extend our ability to exploit antibody specificity in chemical catalysis, diagnostics, and therapeutics, but may also prove generally applicable to the functional modification of other proteins for which detailed structural information is unavailable. 相似文献
338.
Effect of temperature on resistance to Potato virus Y in potato cultivars carrying the resistance gene Rychc
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The effect of cultivation temperatures on the resistance reaction to three Potato virus Y strains (PVYO, PVYN and PVYNTN) in potato cultivars carrying Rychc was examined. When potato plants carrying Rychc were cultivated at 22 °C, a few small necrotic spots developed on inoculated leaves by 5 days after mechanical inoculation (dpi), and systemic infection of a few symptomless plants was confirmed at 28 dpi by IC‐RT‐PCR. At 28 °C, distinct necrotic spots developed on inoculated leaves by 5 dpi, and systemic symptoms occasionally appeared at 28 dpi. Thus, high temperature weakens Rychc‐conferred resistance. However, the incidence of systemic infection and the titre of virus in resistant cultivars at 28 °C were lower than in a susceptible cultivar. In graft inoculation under high summer temperatures, some plants developed necrosis on the leaves and stem, but PVY was barely detected by RT‐PCR in leaves on potato carrying Rychc. When seedlings from progeny tubers of plants that were inoculated with PVY and grown in a greenhouse at >30 °C in the daytime were examined by ELISA and IC‐RT‐PCR, PVY was not detected in cultivars carrying Rychc. These results show that Rychc confers an extreme resistance to PVY strains occurring in Japan. 相似文献