<Emphasis Type="Italic">Pseudomonas</Emphasis> sp. LSW25R,antagonistic to plant pathogens,promoted plant growth,and reduced blossom-end rot of tomato fruits in a hydroponic system

A Gram-negative rhizobacterial isolate (LSW25) antagonistic to Pseudomonas corrugata, a vein necrosis pathogen of tomato, and promotes the growth of tomato seedlings was isolated from surface-sterilised tomato roots. A spontaneous rifampicin-resistant mutant (LSW25R) was selected to facilitate its tracking, and identified as Pseudomonas sp. and named as Pseudomonas sp. LSW25R (LSW25R), based on its sequences of the internal transcribed spacer (ITS) region and 16 S rRNA gene. LSW25R inhibited mycelial growth of 12 other plant fungal pathogens such as Botrytis cinerea on V8 agar plates. By using a scanning electron microscope, LSW25R colonised not only the root surface around the natural aperture of tomato radicles but also under epidermal cells like endophytic bacteria. LSW25R successfully colonised the roots of tomato, eggplant and pepper seedlings, significantly promoted the fresh weight, height and dry matter of tomato plants at 10⁸ cfu·ml⁻¹, and increased the plant growth of eggplants and peppers at 10⁴ cfu·ml⁻¹, suggesting that the optimal population density of LSW25R for growth promotion varies from species to species. Moreover, densities of LSW25R inside roots and the lowest leaf of tomato plants were > 9.3 × 10³ cfu·g⁻¹. Although the growth promotion of tomato by LSW25R was observed under N- or Ca-deficient conditions as well as a standard nutrient condition, the uptake of calcium was increased only under the standard nutrient condition. In a hydroponic system, LSW25R not only successfully colonised the rhizosphere during cultivation due to its broad spectrum of antifungal activity and endophytic colonisation, but also reduced blossom-end rot of tomato fruits presumably through increasing calcium uptake.     

Evaluation of PCR inhibitory effect of enrichment broths and comparison of DNA extraction methods for detection of Salmonella Enteritidis using real-time PCR assay

The best enrichment broth and DNA extraction scheme was determined for rapid and sensitive detection of Salmonella Enteritidis in steamed pork using real-time PCR. The inhibitory effect of commonly used Salmonella enrichment broths, Rappaport-Vassiliadis (RV) and Muller-Kauffmann tetrathionate with novobiocin (MKTTn), on real-time PCR was confirmed. The inhibition of PCR was statistically significant (p < 0.05) in RV and MKTTn, as compared with buffered peptone water (BPW) or phosphate-buffered saline. The inhibitory effect of the selective enrichment media was successfully removed by using a modified DNA extraction, PrepMan Ultra Reagent with an additional washing step or the DNeasy Tissue Kit. In three experiments, when applied to detection of Salmonella Enteritidis in steamed pork, the real-time PCR coupled with single 24 h enrichment with BPW performed better than double 48 h enrichment with BPW plus RV or MKTTn. The simple real-time PCR assay using BPW proved to be a rapid and sensitive test for detection of low concentrations of Salmonella Enteritidis in steamed pork samples as compared with the conventional culture method.     

宁夏灌区渠道衬砌破坏成因分析与防治措施探究

在多年工程实践及调查研究的基础上,总结影响渠道防渗衬砌冻胀破坏的主要因素:渠床土质、冻土深度、地下水埋深、渠道走向、衬砌结构型式及材料对衬砌渠道防冻胀的影响,提出应用防渗新材料、换填弱冻胀性土、隔热保温等削减或适应冻胀的措施.     

An Outbreak of Highly Pathogenic Avian Influenza at a Public Animal Exhibit in Seoul,Korea, During 2008

This study describes the first recorded outbreak of HPAI in the city of Seoul, in captive birds held in an exhibition for public viewing at a local district office. The index cases were two pheasants, which had been introduced into the exhibit on 24 April, 4 days prior to death, from a store in a local market in Gyeonggi‐do. Ducks and chickens from an HPAI outbreak farm, subsequently confirmed on 4 May, had also been held in this store. This outbreak highlights the potential role of local markets in AIV transmission. This outbreak led to considerable public health concern in Korea, however, no human cases were reported. The non‐commercial poultry sector needs to be considered in national plans for preparedness and response.     

基于绿色价值链的绿色价格研究

低碳时代的到来,使得众多企业越来越关注绿色营销,而价格作为营销最重要的要素之一也自然被营销者和消费者同时关注,能否制定合理的绿色价格,对企业赢得消费者的信赖、获得良好的经济效益和社会效益都是非常重要的。笔者基于迈克尔?波特的价值链模型,阐述了绿色价值链的概念,并将绿色价值链管理引入绿色价格机制。有效的绿色价值链管理能够缩减生产成本、降低产品价格,笔者着重从绿色价值链体系中的顾客价值链、绿色回收及与绿色价值链密切相关的人力资源管理三个方面对如何降低绿色产品价格进行分析,以此获取绿色成本的竞争优势。绿色价格战略是绿色营销战略最主要的组成部分。企业通过优化内、外部顾客价值链、重视绿色回收环节以及加强对绿色人才的引进等措施来获取绿色价格的竞争优势,树立企业绿色形象。     

Flavonoid content in fresh, home-processed, and light-exposed onions and in dehydrated commercial onion products

Onion plants synthesize flavonoids as protection against damage by UV radiation and by intracellular hydrogen peroxide. Because flavonoids also exhibit health-promoting effects in humans, a need exists to measure their content in onions and in processed onion products. To contribute to the knowledge about the levels of onion flavonoids, HPLC and LC-MS were used to measure levels of seven quercetin and isorhamnetin glucosides in four Korean commercial onion bulb varieties and their distribution within the onion, in scales of field-grown onions exposed to home processing or to fluorescent light and in 16 commercial dehydrated onion products sold in the United States. Small onions had higher flavonoid content per kilogram than large ones. There was a graduated decrease in the distribution of the flavonoids across an onion bulb from the first (outside) to the seventh (innermost) scale. Commercial, dehydrated onion products contained low amounts or no flavonoids. Losses of onion flavonoids subjected to "cooking" (in percent) ranged as follows: frying, 33; sauteing, 21; boiling, 14-20; steaming, 14; microwaving, 4; baking, 0. Exposure to fluorescent light for 24 and 48 h induced time-dependent increases in the flavonoid content. The results extend the knowledge about the distribution of flavonoids in fresh and processed onions.     

Evaluation of land surface radiation balance derived from moderate resolution imaging spectroradiometer (MODIS) over complex terrain and heterogeneous landscape on clear sky days

Many studies on land surface radiation balances have relied on geostationary satellites. These satellites have provided data with high temporal resolution (less than 3 h); however, the spatial resolution was too coarse (20–250 km scale) to investigate local-scale land surface radiation balances. Moderate resolution imaging spectroradiometer (MODIS) – onboard both the Terra and Aqua satellites – yields a tradeoff with regard to this problem by providing higher spatial resolution (1 km scale) and sensing all over the earth nearly twice a day during daytime; this provides a potential tool for the periodical monitoring of the land surface energy balance. The reliability of MODIS-derived estimates is, however, affected by the presence of multiple error sources, such as those related to heterogeneous land cover and complex topography. In this study, we have used atmospheric (5 and 10 km scale) and land (1 km scale) products obtained from both the Terra and Aqua MODIS devices as inputs in order to estimate the radiation components (1 km scale) under clear daytime conditions over a heterogeneous farmland area and a rugged deciduous forest in the Korea Flux Network (KoFlux). The reliability of these estimates and the associated errors were evaluated by comparing against field measurements taken for 41 and 26 clear days with regard to the farmland and forest sites, respectively. Solar radiation was successfully retrieved with a root mean square error (RMSE) of 20 W m⁻² for both the Terra and Aqua devices over the flat farmland site, whereas the rugged forest site exhibited corresponding values of 40 and 65 W m⁻² RMSE values with consistent positive biases (presumably caused by topographic effects). The RMSE values of the downward longwave radiation were 20 W m⁻² for both the Terra and Aqua devices for both these sites. The sensitivities of the upward components of the shortwave and longwave radiations varied with the RMSE values to the scale of the spatial heterogeneity of both the sites. Consequently, the RMSE values of the net radiation ranged from 33 to 61 W m⁻² for both the devices at both the sites. Our results suggest that the scales of the patch mosaics within the landscapes need to be quantified for proper retrieval of the MODIS-derived radiation products. More extensive validation efforts are required to identify and account for major error sources across diverse land surface conditions.