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.

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.

Rapid Treatment Using Vacuum-surcharge Preloading with Dynamic Consolidation Method: Laboratory Model Test

Xiaobing Li,Jun Li,You Zhou,Tian Jin,Mingfeng Li 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

This study presents an experimental investigation of reinforcement effect of dredged fill obtained from the Oufei project of Wenzhou, China using improved method of vacuum-surcharge preloading with dynamic consolidation by five parallel laboratory model tests: four model tests with different tamping energy combinations and a control group of vacuum-surcharge preloading method. The water content after treatment of the vacuum-surcharge preloading method was close to the optimal water content obtained from standard compactiontest. The treatment of improved method of vacuum-surcharge preloading with dynamic consolidation can improve reinforcement effect and shorten consolidation time. The tests with higher tamping energy have a higher range of improvement. Under the condition of the identical level of tamping energy, compared with the drop height, the weight of hammer plays a greater role in foundation reinforcement, embodying concretely in water discharge, crater depth, and dissipation of pore water pressure, water content, vane shear strength, and porosity.The findings from this study may benefit the engineering application and further research of the combined method.

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.

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.

Ginsenosides: potential therapeutic source for fi brosis-associated human diseases

Xiaobing Li,Nan Mo,Zhenzhen Li 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.3

Tissue fibrosis is an eventual pathologic change of numerous chronic illnesses, which is characterized byresident fibroblasts differentiation into myofibroblasts during inflammation, coupled with excessiveextracellular matrix deposition in tissues, ultimately leading to failure of normal organ function. Now,there are many mechanistic insights into the pathogenesis of tissue fibrosis, which facilitate the discoveryof effective antifibrotic drugs. Moreover, many chronic diseases remain a significant clinical unmetneed. For the past five years, many research works have undoubtedly addressed the functionaldependency of ginsenosides in different types of fibrosis and the successful remission in various animalmodels treated with ginsenosides. Caveolin-1, interleukin, thrombospondin-1 (TSP-1), liver X receptors(LXRs), Nrf2, microRNA-27b, PPARd-STAT3, liver kinase B1 (LKB1)-AMPK, and TGF-b1/Smads are potentialtherapy targeting using ginsenosides. Ginsenosides can play a targeting role and suppress chronicinflammatory response, collagen deposition, and epithelialemesenchymal transition (EMT), as well asmyofibroblast activation to attenuate fibrosis. In this report, our aim was to focus on the therapeuticprospects of ginsenosides in fibrosis-related human diseases making use of results acquired from variousanimal models. These findings should provide important therapeutic clues and strategies for theexploration of new drugs for fibrosis treatment.

The Molecular Pathogenesis of Pituitary Adenomas:An Update

Xiaobing Jiang,Xun Zhang 대한내분비학회 2013 Endocrinology and metabolism Vol.28 No.4

Pituitary tumors represent the most common intracranial neoplasms accompanying serious morbidity through mass effects and inappropriate secretion of pituitary hormones. Understanding the etiology of pituitary tumorigenesis will facilitate the development of satisfactory treatment for pituitary adenomas. Although the pathogenesis of pituitary adenomas is largely unknown, considerable evidence indicates that the pituitary tumorigenesis is a complex process involving multiple factors, including genetic and epigenetic changes. This review summarized the recent progress in the study of pituitary tumorigenesis, focusing on the role of tumor suppressor genes, oncogenes and microRNAs.

Convex solutions of the polynomial-like iterative equation on open set

Xiaobing Gong 대한수학회 2014 대한수학회보 Vol.51 No.3

Because of difficulty of using Schauder’s fixed point theorem to the polynomial-like iterative equation, a lots of work are contributed to the existence of solutions for the polynomial-like iterative equation on compact set. In this paper, by applying the Schauder-Tychonoff fixed point theorem we discuss monotone solutions and convex solutions of the polynomial-like iterative equation on an open set (possibly unbounded) in RN. More concretely, by considering a partial order in RN defined by an order cone, we prove the existence of increasing and decreasing solutions of the polynomial-like iterative equation on an open set and further obtain the conditions under which the solutions are convex in the order.

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.