Pathophysiology of enteropathogenic Escherichia coli during a host infection     

Jun Bong Lee  Se Kye Kim  Jang Won Yoon 《Journal of veterinary science (Suw?n-si, Korea)》2022,23(2)

Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.  相似文献   

PCB removal,soil enzyme activities,and microbial community structures during the phytoremediation by alfalfa in field soils   总被引：1，自引：1，他引：1  

Chen Tu  Ying Teng  Yongming Luo  Xianghui Sun  Shaopo Deng  Zhengao Li  Wuxing Liu  Zhihong Xu 《Journal of Soils and Sediments》2011,11(4):649-656

Purpose  

An in situ phytoremediation trial was developed in order to investigate the function of alfalfa during a 2-year bioremediation of an agricultural soil contaminated with polychlorinated biphenyls (PCBs). The study was conducted with the aim to better understand the application potential of PCB phytoremediation at field scale.  相似文献   

Effects of green tea polyphenol (-)-epigallocatechin-3-gallate on newly developed high-fat/Western-style diet-induced obesity and metabolic syndrome in mice     

Chen YK  Cheung C  Reuhl KR  Liu AB  Lee MJ  Lu YP  Yang CS 《Journal of agricultural and food chemistry》2011,59(21):11862-11871

The aim of this study was to investigate the effects of (-)-epigallocatechin-3-gallate (EGCG) on newly developed high-fat/Western-style diet-induced obesity and symptoms of metabolic syndrome. Male C57BL/6J mice were fed a high fat/Western-style (HFW; 60% energy as fat and lower levels of calcium, vitamin D(3), folic acid, choline bitartrate, and fiber) or HFW with EGCG (HFWE; HFW with 0.32% EGCG) diet for 17 wks. As a comparison, two other groups of mice fed a low-fat diet (LF; 10% energy as fat) and high-fat diet (HF; 60% energy as fat) were also included. The HFW group developed more body weight gain and severe symptoms of metabolic syndrome than the HF group. The EGCG treatment significantly reduced body weight gain associated with increased fecal lipids and decreased blood glucose and alanine aminotransferase (ALT) levels compared to those of the HFW group. Fatty liver incidence, liver damage, and liver triglyceride levels were also decreased by the EGCG treatment. Moreover, the EGCG treatment attenuated insulin resistance and levels of plasma cholesterol, monocyte chemoattractant protein-1 (MCP-1), C-reactive protein (CRP), interlukin-6 (IL-6), and granulocyte colony-stimulating factor (G-CSF). Our results demonstrate that the HFW diet produces more severe symptoms of metabolic syndrome than the HF diet and that the EGCG treatment can alleviate these symptoms and body fat accumulation. The beneficial effects of EGCG are associated with decreased lipid absorption and reduced levels of inflammatory cytokines.  相似文献   

Hydroxycinnamoylmalic acids and their methyl esters from pear (Pyrus pyrifolia Nakai) fruit peel     

Lee KH  Cho JY  Lee HJ  Ma YK  Kwon J  Park SH  Lee SH  Cho JA  Kim WS  Park KH  Moon JH 《Journal of agricultural and food chemistry》2011,59(18):10124-10128

Two novel caffeoylmalic acid methyl esters, 2-O-(trans-caffeoyl)malic acid 1-methyl ester (6) and 2-O-(trans-caffeoyl)malic acid 4-methyl ester (7), were isolated from pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit peels. In addition, 5 known hydroxycinnamoylmalic acids and their methyl esters were identified: 2-O-(trans-coumaroyl)malic acid (1), 2-O-(cis-coumaroyl)malic acid (2), 2-O-(cis-coumaroyl)malic acid 1-methyl ester (3), 2-O-(trans-coumaroyl)malic acid 1-methyl ester (4), and 2-O-(trans-caffeoyl)malic acid (phaselic acid, 5). The chemical structures of these compounds were determined by spectroscopic data from ESI MS and NMR. Of all the isolated compounds, five hydroxycinnamoylmalic acids and their methyl esters (2-4, 6, 7) were identified in the pear for the first time.  相似文献   

Variation and correlation analysis of flavonoids and carotenoids in Korean pigmented rice (Oryza sativa L.) cultivars     

Kim JK  Lee SY  Chu SM  Lim SH  Suh SC  Lee YT  Cho HS  Ha SH 《Journal of agricultural and food chemistry》2010,58(24):12804-12809

Flavonoids and carotenoids of pigmented rice ( Oryza sativa L.), including five black cultivars and two red cultivars, from Korea were characterized to determine the diversity among the phytochemicals and to analyze the relationships among their contents. Black cultivars were higher in flavonoids and carotenoids than the red and white cultivars. The profiles of eight phytochemicals identified from the rice grains were subjected to principal component analysis (PCA) to evaluate the differences among cultivars. PCA could fully distinguish between these cultivars. The Heugjinjubyeo (BR-1) and Heugseolbyeo (BR-2) cultivars were separated from the others based on flavonoid and carotenoid concentrations. Flavonoid contents had a positive correlation with carotenoid contents among all rice grains. The BR-1 and BR-2 cultivars appear to be good candidates for future breeding programs because they have simultaneously high flavonoid and carotenoid contents.  相似文献   

Atmospheric Mercury Fluxes in a Southern Boreal Forest and Wetland     

Katriina Kyllönen  Hannele Hakola  Heidi Hellén  Markku Korhonen  Matti Verta 《Water, air, and soil pollution》2012,223(3):1171-1182

Total gaseous mercury (TGM) fluxes from the forest floor and a boreal wetland were measured by a flux chamber technique coupled with an automatic mercury vapour analyser. The fluxes were measured at three sampling sites in southern Finland, 61°14′ N, 25°04′ E in summer 2007, with additionally in situ TGM concentrations in the air at one of the sites and mercury bulk deposition at another. Most of the flux data were collected during the daytime. At one of the sites, diurnal flux behaviour was studied, and a clear cycle with an afternoon maximum and a night minimum was observed. The highest emissions (up to 3.5 ng m⁻² h⁻¹) were observed at the forest floor site having a moss and grass cover. At the wetland and litter-rich forest floor sites, the emissions were below 1 ng m⁻² h⁻¹ and sometimes negative (down to −1.0 ng m⁻² h⁻¹), indicating mercury uptake. The measured average fluxes in August were 0.9 ± 1.1 and 0.2 ± 0.3 ng m⁻² h⁻¹ for the forest floor sites and wetland sites, respectively. The flux data were compared with the mercury bulk deposition, which proved to be of the same magnitude, but opposite in sign. At the mossy forest floor site, the extrapolated TGM emissions were 130% of the Hg deposition in August 2007. Comparison with other studies showed that the fluxes in background areas are relatively uniform, regardless of measurement site location and method used. Airborne TGM remained at the background level during the study, with an average value of 1.3 ± 0.2 ng m⁻³; it frequently showed a diurnal cycle pattern.  相似文献   

Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant <Emphasis Type="Italic">Sedum alfredii</Emphasis>     

Kai Wang  Zhiqiang Zhu  Huagang Huang  Tingqiang Li  Zhenli He  Xiaoe Yang  Ashok Alva 《Journal of Soils and Sediments》2012,12(4):556-564

Purpose  

Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil were reported in this study.  相似文献   

Performance and Kinetic Study on Bioremediation of Diazo Dye (Reactive Black 5) in Wastewater Using Spent GAC–Biofilm Sequencing Batch Reactor     

Soon-An Ong  Li-Ngee Ho  Yee-Shian Wong  Komalathevi Raman 《Water, air, and soil pollution》2012,223(4):1615-1623

Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewater. The aim of this study was to investigate the treatment of diazo dye Reactive Black 5 (RB5)-containing wastewater using granular activated carbon (GAC)–biofilm sequencing batch reactor (SBR) as an integration of aerobic and anaerobic process in a single reactor. The GAC–biofilm SBR system demonstrated higher removal of COD, RB5 and aromatic amines. It was observed that the RB5 removal efficiency improved as the concentration of co-substrate in the influent increased. The alternative aeration introduced into the bioreactor enhanced mineralization of aromatic amines. Degradation of RB5 and co-substrate followed second-order kinetic and the constant (k ₂) values for COD and RB5 decreased from 0.002 to 0.001 and 0.004 to 0.001 l/mg h, respectively, as the RB5 concentration increased from 100 to 200 mg/l in the GAC–biofilm SBR system.  相似文献   

Long-Term Fertilization Effects on Rice Productivity and Nutrient Efficiency in Korean Paddy     

Chang Hoon Lee  Ui Gum Kang  Ki Do Park  Do Kyoung Lee  Pil Joo Kim 《Journal of plant nutrition》2013,36(8):1496-1506

ABSTRACT

Long-term fertilization tests evaluated rice (Oryza sativa) productivity in relation to application of nitrogen (N)-phosphorus (P)-potassium (K) (120-34.9-66.7 kg ha^{? 1}, respectively) during 1967–1972 and N-P-K (150-43.7-83.3 kg ha^{? 1}, respectively) during 1973–2000. The comparison treatments (NP, PK, and NK) and the control (not fertilized) were selected for calculating nutrient efficiency. Rice grain yield increased at a 17.78 kg ha^{? 1} yr^{? 1} in the control, mainly due to development of improved cultivars. Phosphorus management was found to be important for indigenous fertility and rice productivity in this paddy soil. Yield increased significantly with P fertilization. Without N fertilization (PK), rice productivity increased 56.85 kg ha^{? 1} yr^{? 1} from 62% of NPK at the initial stage to 74% after passing 34 years, which might be affected by increasing biological N fixation with P accumulation in soil. In NK treatment, rice yield increased at a relatively low rate (37.82 kg hr^{? 1} yr^{? 1}) from the same rice productivity with that of NPK in 1967 to 91% after 34 years. In comparison, yield increased at a high rate (62.82 kg hr^{? 1} yr^{? 1}) without K fertilization (NP) from ca. 90% of NPK and might exceed the yield of NPK after 64 years of long-term fertilization. Therefore, K fertilization level might be readjusted after long-term fertilizing in paddy soil.  相似文献   

Utilization of biochar impregnated with anaerobically digested slurry as slow‐release fertilizer          下载免费PDF全文

Taek‐Keun Oh  Yoshiyuki Shinogi  Seung‐Joo Lee  Bongsu Choi 《植物养料与土壤学杂志》2014,177(1):97-103

We examined the possibility of an environment‐friendly slow‐release fertilizer (SRF) made of biochar impregnated by anaerobically digested slurry. The biochar materials were produced from three types of feedstocks (orange peel, residual wood, water‐treatment sludge) at different temperatures of 300°C, 500°C, and 700°C via pyrolysis. The release behaviors of the water‐soluble K⁺, Ca²⁺, and Mg²⁺ were similar for all impregnated biochars and the commercial SRF used. The water‐retention capacity was greatly improved by mixing the biochar‐SRF with the soil. The yield of lettuce was lower for the biochar‐SRF applications of 3.7 to 34.2 t ha^–1 than for the commercial SRF application of 51.4 t ha^–1. This might be due to excessive increase of soil pH for the biochar‐SRF application. Based on these results, the authors concluded that the biochar impregnated with nutrients could become an effective slow‐release K⁺ fertilizer.  相似文献