Hyperosmotic Adaptation of Pseudomonas protegens SN15-2 Helps Cells to Survive at Lethal Temperatures

Xiaobing Wang,Danyan Tang,Wei Wang 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.3

Pseudomonas protegens is a gram-negative bacterium with an excellent biological control effect. Compared to standard cells growing in NaCl-free media, the ability of the hyperosmotic cells (450 mM NaCl) to resist high temperatures and freezing was significantly improved. It is of great significance to apply the P. protegens to elaborate on the hyperosmotic adaptation mechanism. RNA-seq was used to sequence P. protegens cultured with 0 mM and 450 mM NaCl. Comparative transcriptomic analyses of the different treatments were performed using gene ontology and the Kyoto encyclopedia of genes and genome. The results revealed that hyperosmotic stress had prominent impacts on the genes involving in multiple cellular functions. The hyperosmotic environment significantly affected carbohydrate, energy, and amino acid metabolism, as well as membrane system and cell motility. Our findings indicated that P. protegens adopted a series of approaches, including the high cytoplasmic concentrations of potassium ions and the uptake or synthesis of osmoprotectants, for surviving hyperosmotic stress. Among these, trehalose and proline synthesis appeared to be an important method to withstand prolonged hyperosmotic stress in P. protegens. These data provide crucial resource that may determine specific responses to the hyperosmotic environment in P. protegens.

Highly selective magnetic polymer particles via molecular imprinting

Xiaobing Wang,Guihua Qiu,Yi Ge,Wei Zheng,Lingmei Kong,Yajuan Xue,Bin Ren,YUXING PENG 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.11

Magnetic hydrophilic molecularly imprinted polymer (MIP) particles were successfully synthesized via an inverse suspension polymerization in silicone oil, by employing methacryloxypropyltrimethoxysilane(MPS)-modified Fe3O4 nanoparticles as magnetic particles, 2,4-dichlorophenoxyacetic acid (2,4-D) as template, hydroxyethyl methacrylate (HEMA) as hydrophilic monomer, and acetonitrile as high polar porogen. The synthesized magnetic hydrophilic MIP particles could be separated rapidly under an external magnetic field. About 94% transmittance of the particlewater suspension could be reached within 20 min by magnetic separation, whereas about 84% transmittance was achieved after at least 180min by sedimentation. The adsorption capacity of the particles was also studied in pure aqueous environments. These hydrophilic MIP particles had a higher selectivity for templates. Hydrophilic MIP particles took on a higher imprinting factor than hydrophobic MIP particles and 2,4-D were able to rebind hydrophilic MIP particles more easily than 4-Chorophenoxyacetic acid.

College education and the poor in China: documenting the hurdles to educational attainment and college matriculation

Xiaobing Wang,Chengfang Liu,Linxiu Zhang,Renfu Luo,Thomas Glauben,Yaojiang Shi,Scott Rozelle,Brian Sharbono 서울대학교 교육연구소 2011 Asia Pacific Education Review Vol.12 No.4

Although universities have expanded in size, it is unclear whether the poor have benefited. If there are high returns to college education, then increasing access of the poor to college has important welfare implications. The objective of this paper is to document the rates of enrollment into college of the poor and to identify the hurdles to doing so. Relying on several sets of data, including a survey of college students from universities in three poor provinces in China, we have found that the college matriculation rate of the poor is substantially lower than students from non-poor families; the same is true for rural women and minorities. Clearly, there are barriers that are keeping the rural poor out. The paper also demonstrates that the real hurdles are not during the years of secondary schooling or at the time of admissions to college. The real impediments keeping the rural poor from pursuing a college education arise long before high school-as early as preschool and elementary school years-and are present throughout the entire schooling system.

Influence of Dynamic Loading Activation Time on Electro-osmotic Consolidation of Soft Soil

Xiaobing Li,Jianyu Shu,Jun Wang,Hongtao Fu,Peng Wang,Xiuqing Hu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

Electro-osmosis is a suitable method for the consolidation of soft soil. However, the significant potential loss caused by the cracking of the soil near the electrode in the later stages of electro-osmosis hinders further improvement of its efficiency. Dynamic loading is applied to overcome this problem. The dynamic loading activation time is considered to strongly influence the performance of the combined electro-osmosis-dynamic loading process. In this paper, the maximum current ratio (MCR) is proposed as an index of the dynamic loading activation time. Laboratory tests were performed with different dynamic loading activation times to confirm the influence of the dynamic loading time on electro-osmosis consolidation. During the combined processes of dynamic loading and electro-osmosis, the current, electric potential, discharged water, and surface settlement were monitored. In the following testing, the water content and undrained shear strength were measured. Compared with the electro-osmosis method alone, electro-osmosis and dynamic loading was found to yield superior performance improvement. The method described in this paper to determine the optimal dynamic loading activation time as a function of the MCR, and electro-osmosis, exhibits potential as an improved approach for the consolidation of soft soil in engineering practice.

Influence of meadow changes on net primary productivity: a case study in a typical steppe area of XilinGol of Inner Mongolia in China

Xiaobing Li,Guoqing Li,Hong Wang,Han Wang,Jingjing Yu 한국지질과학협의회 2015 Geosciences Journal Vol.19 No.3

In this research, we monitored the change (degeneration or improvement) in meadow vegetation over an approximately 12-year timespan in the typical steppe area of Inner Mongolia in China. Linear trend analysis (LTA) and the MOD13Q1-NDVI time series data were used to evaluate the changes in the net primary productivity (NPP) during the vegetation growing seasons between 2000 and 2011. The Carnegie Ames Stanford Approach (CASA) model was used, and the relationship between the vegetation change and meadow NPP was analyzed and validated with field data collected in 2011. The results indicate the following: (1) the growth status and NPP of the meadow vegetation in the typical steppe area of Inner Mongolia varied greatly for each year without an obvious linear trend between the change of meadow vegetation and NPP; (2) additional analysis with field measured data, collected in 2011, revealed that the average dry weight of the above-ground biomass in the area where the NPP had increased was less than that in the area where it had decreased; the dry weight of the above-ground biomass of the meadow vegetation that showed degeneration was greater than that of the meadow vegetation that showed improvement; (3) a possible reason for the phenomenon mentioned in (2) was that the government protected the degenerated meadows with less biomass, which led to vegetation growth and increased NPP, whereas the meadows that had not been degenerated or showed only minor degeneration and still received rich biomass were over-grazed, causing the NPP to decline.

Glutathione disulfide sensitizes hepatocytes to TNFα-mediated cytotoxicity via IKK-β S-glutathionylation: a potential mechanism underlying non-alcoholic fatty liver disease

Xiaobing Dou,Songtao Li,Linfeng Hu,Lei Ding,Yue Ma,Wang Ma,Hui Chai,Zhenyuan Song 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Oxidative stress and TNFα are critically involved in the initiation and progression of non-alcoholic fatty liver disease (NAFLD). In this study, we investigated the effects of dysregulated glutathione homeostasis, a principal feature of oxidative stress, on TNFα-induced hepatotoxicity and its mechanistic implications in NAFLD progression. We showed that mice fed a high-fat diet (HFD) for 12 weeks developed hepatic steatosis and liver injuries, which were associated with not only TNFα overproduction but also hepatic glutathione dysregulation, characterized by GSH reduction and GSSG elevation. Moreover, consuming a HFD increased protein S-glutathionylation (protein-SSG formation) in the liver. Subsequent cell culture studies revealed that GSSG accumulation, as opposed to GSH reduction, sensitized hepatocytes to TNFα killing by reducing the TNFα-triggered NF-κB activity. GSSG prevented TNFα-induced activation of IKK-β, an upstream kinase in the NF-κB signaling pathway, by inducing IKK-β glutathionylation (IKK-β-SSG formation). In animal studies, in comparison to a control diet, HFD consumption resulted in increased hepatic IKK-β- SSG formation, leading to suppressed IKK-β activation and subsequent NF-κB suppression. Furthermore, we found that HFD consumption also led to decreased hepatic expression of glutaredoxin, a key enzyme for de-glutathionylation. Similarly, CdCl2, a chemical inhibitor of glutaredoxin, sensitized hepatocytes to TNFα-mediated cytotoxicity. In conclusion, our data suggest that GSSG is a potent and clinically relevant sensitizer for TNFα-induced hepatotoxicity in NAFLD, which represents a potential therapeutic target for NAFLD.

Effect of electrochemical treatment on consolidation of soft clay

Li, Xiaobing,Yuan, Guohui,Fu, Hongtao,Wang, Jun,Cai, Yuanqiang Techno-Press 2018 Geomechanics & engineering Vol.15 No.4

In this study, a method of electrochemical consolidation is applied. This method utilizes electro-osmosis, which is an effective ground improvement technique for soft clays, and soil treatment using lime, which is the oldest traditional soil stabilizer. The mechanism of lime treatment for soil involves cation exchange, which leads to the flocculation and agglomeration. Five representative laboratory tests-an electro-osmotic test and four electrochemical tests with various proportions of lime-were performed on dredged marine clay. The objectives of this study are to investigate the effect of electrochemical treatment and to determine the optimum dose for optimal consolidation performance of dredged marine clay. The results show that a better consolidation effect was achieved in terms of current, temperature, and vane shear strength by using electrochemical treatment. The best results were observed for the electrochemical test using 4% lime content.

Research on soil net nitrogen mineralization in Stipa grandis grassland with different stages of degradation

Wanyu Wen,Xiaobing Li,Lihong Chen,Dandan Wei,Han Wang,Meng Zhang,Jing Yu 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.4

Net nitrogen mineralization is one of the nitrogen cycling process, and it is very important to understand nitrogen mineralization characteristics in degradation grassland. In the upper 0–10 cm soil layer of Stipa grandis P. A. Smirn. grassland in the Xilin river basin, Inner Mongolia, we studied the soil net nitrogen mineralization and nitrification among three varying stages of degradation grassland and analyzed the relationship between the mineralization rate of the soil net nitrogen and environmental factors, using the resin-core incubation method. Our results demonstrated that, from May to October 2012, the accumulated net nitrogen mineralization was 21.620 mg kg–1, 12.486 mg kg–1, and 48.053 mg kg–1 in the slightly, medium, and heavily degraded grasslands, respectively and varied greatly among the three stages of degradation shown by the S. grandis grassland plots. During the cultivation period, the variation of net nitrogen mineralization and nitrification was similar to the variation of soil mineral nitrogen. The higher soil mineral nitrogen content indicated higher mineralization of net nitrogen. In July and August, soil moisture was positively correlated with the net nitrogen mineralization rate, and the correlation coefficients between these two factors of 0.73, 0.58, and 0.79 for the slightly, medium, and heavily degraded plots, respectively. The rates of net nitrogen mineralization and nitrification were negatively correlated with soil total nitrogen, but positively correlated with C/N ratio, and weakly correlated with other physicochemical properties.

Experimental Study on the Effect of Additives on Drainage Consolidation in Vacuum Preloading Combined with Electroosmosis

Jianli Hu,Xiaobing Li,Dikang Zhang,Jun Wang,Xiuqing Hu,Yuanqiang Cai 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.9

Vacuum-electroosmosis is a common method of foundation treatment; however, it is disadvantaged by fine soil particles clogging the drainage plate. To overcome this issue, this study treated the dredged fill from vacuum-electroosmosis with different additives. The parameters of discharged water, current, water content, and shear strength of soils treated with different amounts of Ca(OH)2, FeCl3, and NaCl were analyzed. The results showed that different additives have different effects on the vacuum-electroosmosis method for reinforcing dredger filling. Excessive additive contents were found to have an adverse effect on vacuum-electroosmosis, and hence, optimum amounts are required for the three additives. On comparing the optimum dosage of these additives, FeCl3 was observed to be the most energy-saving. From the aspect of anode corrosion and the costs involved, Ca(OH)2 was the most economical. For practical engineering applications, Ca(OH)2 was the most preferable additive. The results of this study provide guidance and scientific criteria for similar dredging foundation treatments.

Metabolic Characteristic of the Liver of Dairy Cows during Ketosis Based on Comparative Proteomics

Xu, Chuang,Wang, Zhe,Liu, Guowen,Li, Xiaobing,Xie, Guanghong,Xia, Cheng,Zhang, Hong You Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.7

The objective of the present study was to identify differences in the expression levels of liver proteins between healthy and ketotic cows, establish a liver metabolic interrelationship of ketosis and elucidate the metabolic characteristics of the liver during ketosis. Liver samples from 8 healthy multiparous Hostein cows and 8 ketotic cows were pooled by health status and the proteins were separated by two-dimensional-electrophoresis (2D-E). Statistical analysis of gels was performed using PDQuest software 8.0. The differences in the expression levels of liver proteins (p<0.05) between ketotic and healthy cows were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF-TOF) tandem mass spectrometry. Five enzymes/proteins were identified as being differentially expressed in the livers of ketotic cows: expression of 3-hydroxyacyl-CoA dehydrogenase type-2 (HCDH), acetyl-coenzyme A acetyltransferase 2 (ACAT) and elongation factor Tu (EF-Tu) were down-regulated, whereas that of alpha-enolase and creatine kinase were up-regulated. On the basis of this evidence, it could be presumed that the decreased expression of HCDH, which is caused by high concentrations of acetyl-CoA in hepatic cells, in the livers of ketotic cows, implies reduced fatty acid ??oxidation. The resultant high concentrations of acetyl-CoA and acetoacetyl CoA would depress the level of ACAT and generate more ??hydroxybutyric acid; high concentrations of acetyl-CoA would also accelerate the Krebs Cycle and produce more ATP, which is stored as phosphocreatine, as a consequence of increased expression of creatine kinase. The low expression level of elongation factor Tu in the livers of ketotic cows indicates decreased levels of protein synthesis due to the limited availability of amino acids, because the most glucogenic amino acids sustain the glyconeogenesis pathway; thus increasing the level of alpha-enolase. Decreased protein synthesis also promotes the conversion of amino acids to oxaloacetate, which drives the Krebs Cycle under conditions of high levels of acetyl-CoA. It is concluded that the livers of ketotic cows possess high concentrations of acetyl-CoA, which through negative feedback inhibited fatty acid oxidation; show decreased fatty acid oxidation, ketogenesis and protein synthesis; and increased gluconeogenesis and energy production.