The Experts below are selected from a list of 3318 Experts worldwide ranked by ideXlab platform
Qiaoyun Huang - One of the best experts on this subject based on the ideXlab platform.
-
Soil Colloids and minerals modulate metabolic activity of pseudomonas putida measured using microcalorimetry
2014Co-Authors: Wenli Chen, Xingmin Rong, Peng Cai, Ke Dai, Qiaoyun HuangAbstract:Substantial interactions of microbes with Soil particles present fundamental influences on microbial activities relevant to a series of biogeochemical processes. However, how Soil surface-active particles modulate microbial metabolism has received scant attention. The extent to which composition of Soil Colloids alter the metabolism is not well addressed. This work examined the impacts of Soil Colloids and minerals on the metabolic activity of Pseudomonas putida using microcalorimetry and carbon utilization. The results showed that montmorillonite remarkably improved metabolic activity of P. putida, whereas kaolinite, goethite and Soil Colloids significantly inhibited the activity. Humus may weaken the inhibition of Soil Colloids on bacterial metabolism via interfacial interaction rather than nutrient supplements. Soils bearing higher amount of kaolinite and iron oxide may have greater depression on bacterial activity. The thermodynamic method provides different and complementary information to that from ...
-
adhesion of bacterial pathogens to Soil colloidal particles influences of cell type natural organic matter and solution chemistry
2014Co-Authors: Wenqiang Zhao, Qiaoyun Huang, Sharon L Walker, Peng CaiAbstract:Abstract Bacterial adhesion to granular Soil particles is well studied; however, pathogen interactions with naturally occurring colloidal particles ( Streptococcus suis SC05 and Escherichia coli WH09 over a wide range of solution pH (4.0–9.0) and ionic strength (IS, 1–100 mM KCl). Cell characterization techniques, Freundlich isotherm, and Derjaguin–Landau–Verwey–Overbeek (DLVO) theory (sphere–sphere model) were utilized to quantitatively determine the interactions between cells and Colloids. The adhesion coefficients ( K f ) of S. suis SC05 to NOM-present and NOM-stripped Soil Colloids were significantly higher than E. coli WH09, respectively. Similarly, K f values of S. suis SC05 and E. coli WH09 adhesion to NOM-stripped Soil Colloids were greater than those Colloids with NOM-present, respectively, suggesting NOM inhibits bacterial adhesion. Cell adhesion to Soil Colloids declined with increasing pH and enhanced with rising IS (1–50 mM). Interaction energy calculations indicate these adhesion trends can be explained by DLVO-type forces, with S. suis SC05 and E. coli WH09 being weakly adhered in shallow secondary energy minima via polymer bridging and charge heterogeneity. S. suis SC05 adhesion decreased at higher IS 100 mM, which is attributed to the change of hydrophobic effect and steric repulsion resulted from the greater presence of extracellular polymeric substances (EPS) on S. suis SC05 surface as compared to E. coli WH09. Hence, pathogen adhesion to the colloidal material is determined by a combination of DLVO, charge heterogeneity, hydrophobic and polymer interactions as a function of solution chemistry.
-
In situ ATR-FTIR study on the adhesion of Pseudomonas putida to Red Soil Colloids
2013Co-Authors: Wenli Chen, Xingmin Rong, Peng Cai, Ke Dai, Qiaoyun HuangAbstract:Purpose Bacterial adhesion to Soil particles is fundamentally important in mineral weathering, organic matter degradation, heavy metal transformation, and fate of pollutants. However, the adhesion mechanism between bacteria and Soil Colloids under continuous flow systems in the natural environments remains unknown.
-
conformation activity and proteolytic stability of acid phosphatase on clay minerals and Soil Colloids from an alfisol
2009Co-Authors: Qiaoyun Huang, Xingmin Rong, Peng Cai, Jun Zhu, Wei Liang, Xueqing Qiao, Wenli ChenAbstract:The present study was carried out to investigate the conformation, enzymatic activity and proteolytic stability of acid phosphatase on montmorillonite, kaolinite and Soil Colloids from an Alfisol by means of circular dichroism (CD) spectroscopy, isothermal titration microcalorimetry (ITC) and biochemical assay, respectively. The results showed that the secondary structure of phosphatase was changed from disordered type to ordered form during adsorption/desorption cycle, organic substance and 2:1-clay mineral in Brown Soil benefited the formation of ordered structure. Enzymatic activity of phosphatase was inhibited while the proteolytic stability was promoted after the interaction with active particles from permanent charge Soil. The decrease of enzymatic activity and the increase of proteolytic stability resulted by montmorillonite and organic colloid were both greater than that by kaolinite and inorganic colloid, which was in consistent with the extent of structural change induced by different colloid particles. Thus, one of the most significant factors responsible for the variation of enzymatic activity and proteolytic stability might be the hiding or even damage of active sites and the irrecognition of cleavage sites in enzyme molecules induced by the formation of ordered structure. The information obtained in this study is of crucial significance for the understanding of the behavior and fate of extracellular enzymes in Soils with permanent charges.
-
role of bacteria in the adsorption and binding of dna on Soil Colloids and minerals
2009Co-Authors: Peng Cai, Qiaoyun Huang, Jun Zhu, Linchun Fang, Wei Liang, Wenli ChenAbstract:Abstract Adsorption and desorption of salmon sperm DNA on bacteria (Bacillus thuringiensis, Pseudomonas putida), two different colloidal fractions (organic and inorganic clay) from an Alfisol, minerals (montmorillonite, kaolinite and goethite) and colloid–bacteria composites were studied. Similar adsorption capacity and affinity of DNA were observed on two bacterial cells. However, the two bacterial strains played different roles in affecting the adsorption of DNA on the composites of Soil colloidal particles with bacteria. The introduction of B. thuringiensis in Soil Colloids and minerals systems dramatically promoted DNA adsorption on colloidal particles especially organic clay, while P. putida decreased the adsorption of DNA on kaolinite and goethite. Electrostatic force and ligand exchange are regarded to be the major driving forces involved in the adsorption of DNA on bacterial cells, montmorillonite, Soil Colloids and goethite. Presence of bacteria enhanced the proportion of DNA adsorption on Soil colloidal particles by electrostatic force and depressed that by ligand exchange process. Information obtained in this study is of fundamental significance for the understanding of the ultimate fate of extracellular DNA in Soil systems.
Erwin Klumpp - One of the best experts on this subject based on the ideXlab platform.
-
citric acid effect on the abundance size and composition of water dispersible Soil Colloids and its relationship to Soil phosphorus desorption a case study
2021Co-Authors: Daniel Menezesblackburn, Erwin Klumpp, Roland Bol, Anna Missong, Volker Nischwitz, P M HaygarthAbstract:Citric acid exudation by plant roots is often linked to the mobilisation of recalcitrant Soil phosphorus (P) for plant nutrition. In this case study, we have explored the effect of citric acid on the abundance, size and composition of water-dispersible Soil Colloids (WDC) to understand the mineral source of desorbed P and the chemical nature of P-carrying mobilized Colloids. After incubation with citric acid, WDC were isolated using a Soil particle-size fractionation method consisting of sedimentation, centrifugation and syringe filtration. The size range and composition of WDC was assessed using field-flow fractionation (FFF), combined with inductively coupled plasma mass spectrometry (ICP-MS) and UV spectrometry, for in vitro P desorption assay samples under the influence of increasing doses of citric acid. Three sharp and well-defined FFF particle size fractions of WDC containing P (12–23, 23–36 and 36–300 nm), with elution times matching carbon (C) peaks and offset from Fe, Al and Si fractions. The concentration of soluble or WDC-associated P, C, Fe, Al and Si increased in response to increasing citric acid doses. Silica Colloids were only detected using syringe filtration below 5 µm. The Si, Fe and Al-containing fine colloid fractions (< 600 nm) were positively correlated with P (de)sorption parameters measured by diffusive gradient in thin films in previous work. The P desorbed by citric acid originated predominantly from the disaggregation of Fe and Al oxides and silicate clays. The citric acid effect on mobilizing organic P carrying WDC fractions may increase Soil organic P cycling and availability to plants.
-
evidence on enhanced transport and release of silver nanoparticles by Colloids in Soil due to modification of grain surface morphology and co transport
2021Co-Authors: Yan Liang, Chongyang Shen, Erwin Klumpp, Yonglu Luo, Scott A BradfordAbstract:Abstract Natural Soils have frequently been considered to decrease the mobility of engineered nanoparticles (NPs) in comparison to quartz sand due to the presence of Colloids that provide additional retention sites. In contrast, this study demonstrates that the transport and release of silver nanoparticles (AgNPs) in sandy clay loam and loamy sand Soils were enhanced in the presence of Soil Colloids that altered Soil grain surface roughness. In particular, we found that the retention of AgNPs in purified Soils (colloid-free and acid-treated) was more pronounced than in raw (untreated) Soils or Soils treated to remove organic matter (H2O2 or 600 °C treated). Chemical analysis and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy demonstrated that the grain surfaces of raw and organic matter-removed Soils were abundant with metal oxides and Colloids compared to purified Soil. Column transport and release experimental results, SEM images, and interaction energy calculations revealed that a significant amount of concave locations on purified Soils hindered AgNP release by diffusion or ionic strength (IS) reduction due to deep primary energy minima. Conversely, AgNPs that were retained in Soils in the presence of Soil Colloids were more susceptible to release under IS reduction because the primary minimum was shallow on the tops of convex locations created by attached Soil Colloids. Additionally, a considerable fraction of retained AgNPs in raw Soil was released after cation exchange followed by IS reduction, while no release occurred for purified Soil under the same conditions. The AgNP release was highly associated with Soil Colloids and co-transport of AgNPs and Soil Colloids was observed. Our work is the first to show that the presence of Soil Colloids can inhibit deposition and facilitate the release and co-transport of NPs in Soil by alteration of the Soil grain surface morphology and shallow primary minimum interactions.
-
role of rain intensity and Soil Colloids in the retention of surfactant stabilized silver nanoparticles in Soil
2018Co-Authors: Joanna Makselon, Nina Siebers, Florian Meier, Harry Vereecken, Erwin KlumppAbstract:Abstract Undisturbed outdoor lysimeters containing arable loamy sand Soil were used to examine the influence of either heavy rain events (high frequency of high rain intensity), steady rain (continuous rainfall of low rain intensity), and natural rainfall on the transport and retention of surfactant-stabilized silver nanoparticles (AgNP). In addition, the AgNP–Soil associations within the Ap horizon were analyzed by means of particle-size fractionation, asymmetrical flow field-flow fractionation coupled with UV/Vis-detection and inductively coupled plasma mass spectrometer (AF4-UV/Vis-ICP-MS), and transmission electron microscopy coupled to an energy-dispersive X-ray (TEM-EDX) analyzer. The results showed that AgNP breakthrough for all rain events was less than 0.1% of the total AgNP mass applied, highlighting that nearly all AgNP were retained in the Soil. Heavy rain treatment and natural rainfall revealed enhanced AgNP transport within the Ap horizon, which was attributed to the high pore water flow velocities and to the mobilization of AgNP–Soil colloid associations. Particle-size fractionation of the Soil revealed that AgNP were present in each size fraction and therefore indicated strong associations between AgNP and Soil. In particular, water-dispersible Colloids (WDC) in the size range of 0.45–0.1 μm were found to exhibit high potential for AgNP attachment. The AF4-UV/Vis-ICP-MS and TEM-EDX analyses of the WDC fraction confirmed that AgNP were persistent in Soil and associated to Soil Colloids (mainly composed of Al, Fe, Si, and organic matter). These results confirm the particularly important role of Soil Colloids in the retention and remobilization of AgNP in Soil. Furthermore, AF4-UV/Vis-ICP-MS results indicated the presence of single, homo-aggregated, and small AgNP probably due to dissolution.
-
phosphorus forms in forest Soil Colloids as revealed by liquid state 31p nmr
2016Co-Authors: Anna Missong, Roland Bol, Sabine Willbold, Jan Siemens, Erwin KlumppAbstract:Nanoparticles and Colloids affect the storage and hence the availability of P in forest ecosystems. We investigated the fine Colloids present in forest Soils and their association with inorganic and organic P. To differentiate between the different P forms, we performed liquid-state 31P-nucelar magnetic resonance (31P-NMR) measurements on forest bulk Soil extracts, on colloid extracts and on the electrolyte phase of their Soil suspensions. The 31P-NMR spectra indicated that Soil nanoparticles and Colloids were more enriched with organic than with inorganic P forms compared to the electrolyte phase. The P concentration was enriched in the colloidal fraction in comparison to the bulk Soil and the phosphate diesters were more dominant in the colloidal fraction when compared to the bulk Soil. The colloidal P-diester to P-monoester ratios were 2 to 3 times higher in the colloidal fraction than in the bulk Soil. In contrast, relatively large percentages of inorganic P were found in the electrolyte phase. Supplementary (not shown) Data are available at the JuSER Server (juser.fz-juelich.de, reference number: FZJ-2016-01739) https://juser.fz-juelich.de/record/283057.
Wenli Chen - One of the best experts on this subject based on the ideXlab platform.
-
Soil Colloids and minerals modulate metabolic activity of pseudomonas putida measured using microcalorimetry
2014Co-Authors: Wenli Chen, Xingmin Rong, Peng Cai, Ke Dai, Qiaoyun HuangAbstract:Substantial interactions of microbes with Soil particles present fundamental influences on microbial activities relevant to a series of biogeochemical processes. However, how Soil surface-active particles modulate microbial metabolism has received scant attention. The extent to which composition of Soil Colloids alter the metabolism is not well addressed. This work examined the impacts of Soil Colloids and minerals on the metabolic activity of Pseudomonas putida using microcalorimetry and carbon utilization. The results showed that montmorillonite remarkably improved metabolic activity of P. putida, whereas kaolinite, goethite and Soil Colloids significantly inhibited the activity. Humus may weaken the inhibition of Soil Colloids on bacterial metabolism via interfacial interaction rather than nutrient supplements. Soils bearing higher amount of kaolinite and iron oxide may have greater depression on bacterial activity. The thermodynamic method provides different and complementary information to that from ...
-
In situ ATR-FTIR study on the adhesion of Pseudomonas putida to Red Soil Colloids
2013Co-Authors: Wenli Chen, Xingmin Rong, Peng Cai, Ke Dai, Qiaoyun HuangAbstract:Purpose Bacterial adhesion to Soil particles is fundamentally important in mineral weathering, organic matter degradation, heavy metal transformation, and fate of pollutants. However, the adhesion mechanism between bacteria and Soil Colloids under continuous flow systems in the natural environments remains unknown.
-
conformation activity and proteolytic stability of acid phosphatase on clay minerals and Soil Colloids from an alfisol
2009Co-Authors: Qiaoyun Huang, Xingmin Rong, Peng Cai, Jun Zhu, Wei Liang, Xueqing Qiao, Wenli ChenAbstract:The present study was carried out to investigate the conformation, enzymatic activity and proteolytic stability of acid phosphatase on montmorillonite, kaolinite and Soil Colloids from an Alfisol by means of circular dichroism (CD) spectroscopy, isothermal titration microcalorimetry (ITC) and biochemical assay, respectively. The results showed that the secondary structure of phosphatase was changed from disordered type to ordered form during adsorption/desorption cycle, organic substance and 2:1-clay mineral in Brown Soil benefited the formation of ordered structure. Enzymatic activity of phosphatase was inhibited while the proteolytic stability was promoted after the interaction with active particles from permanent charge Soil. The decrease of enzymatic activity and the increase of proteolytic stability resulted by montmorillonite and organic colloid were both greater than that by kaolinite and inorganic colloid, which was in consistent with the extent of structural change induced by different colloid particles. Thus, one of the most significant factors responsible for the variation of enzymatic activity and proteolytic stability might be the hiding or even damage of active sites and the irrecognition of cleavage sites in enzyme molecules induced by the formation of ordered structure. The information obtained in this study is of crucial significance for the understanding of the behavior and fate of extracellular enzymes in Soils with permanent charges.
-
role of bacteria in the adsorption and binding of dna on Soil Colloids and minerals
2009Co-Authors: Peng Cai, Qiaoyun Huang, Jun Zhu, Linchun Fang, Wei Liang, Wenli ChenAbstract:Abstract Adsorption and desorption of salmon sperm DNA on bacteria (Bacillus thuringiensis, Pseudomonas putida), two different colloidal fractions (organic and inorganic clay) from an Alfisol, minerals (montmorillonite, kaolinite and goethite) and colloid–bacteria composites were studied. Similar adsorption capacity and affinity of DNA were observed on two bacterial cells. However, the two bacterial strains played different roles in affecting the adsorption of DNA on the composites of Soil colloidal particles with bacteria. The introduction of B. thuringiensis in Soil Colloids and minerals systems dramatically promoted DNA adsorption on colloidal particles especially organic clay, while P. putida decreased the adsorption of DNA on kaolinite and goethite. Electrostatic force and ligand exchange are regarded to be the major driving forces involved in the adsorption of DNA on bacterial cells, montmorillonite, Soil Colloids and goethite. Presence of bacteria enhanced the proportion of DNA adsorption on Soil colloidal particles by electrostatic force and depressed that by ligand exchange process. Information obtained in this study is of fundamental significance for the understanding of the ultimate fate of extracellular DNA in Soil systems.
-
Soil Colloids bound plasmid dna effect on transformation of e coli and resistance to dnase i degradation
2007Co-Authors: Peng Cai, Qiaoyun Huang, Wenli Chen, D Zhang, K Wang, Daihua Jiang, Wei LiangAbstract:Abstract The adsorption and binding of plasmid p34S DNA on four different colloidal fractions from a Brown Soil and clay minerals in the presence of various Ca 2+ concentrations, the ability of bound DNA to transform competent cells of CaCl 2 -treated Escherichia coli , and the resistance of bound DNA to degradation by DNase I were studied. DNA adsorption on Soil Colloids and clay minerals was promoted in the presence of Ca 2+ . Kaolinite exhibited the highest adsorption affinity for DNA among the examined Soil Colloids and clay minerals. In comparison with organo-mineral complexes (organic clays) and fine clays ( 2 O 2 -treated clays (inorganic clays) and coarse clays (0.2–2 μm). The transformation efficiency of bound DNA increased with increasing concentrations of Ca 2+ at which Soil colloid or clay mineral-DNA complexes were formed. DNA bound by kaolinite showed the lowest transformation efficiency, and especially no transformants were observed with kaolinite-DNA complex prepared at 5–100 mM Ca 2+ . Compared to organic clays and fine clays, DNA bound on inorganic clays and coarse clays showed a lower capacity to transform E. coli at different Ca 2+ concentrations. The presence of Soil Colloids and minerals provided protection to DNA against degradation by DNase I. Montmorillonite, organic clays and fine clays showed stronger protective effects for DNA than inorganic clays and coarse clays. The protection mechanisms as well as the differences in transforming efficiency of plasmid DNA molecules bound on various Soil colloidal particles are discussed. The information obtained in this study is of fundamental significance for the understanding of the horizontal dissemination of recombinant DNA and the fate of extracellular DNA in Soil environments.
Peng Cai - One of the best experts on this subject based on the ideXlab platform.
-
Soil Colloids and minerals modulate metabolic activity of pseudomonas putida measured using microcalorimetry
2014Co-Authors: Wenli Chen, Xingmin Rong, Peng Cai, Ke Dai, Qiaoyun HuangAbstract:Substantial interactions of microbes with Soil particles present fundamental influences on microbial activities relevant to a series of biogeochemical processes. However, how Soil surface-active particles modulate microbial metabolism has received scant attention. The extent to which composition of Soil Colloids alter the metabolism is not well addressed. This work examined the impacts of Soil Colloids and minerals on the metabolic activity of Pseudomonas putida using microcalorimetry and carbon utilization. The results showed that montmorillonite remarkably improved metabolic activity of P. putida, whereas kaolinite, goethite and Soil Colloids significantly inhibited the activity. Humus may weaken the inhibition of Soil Colloids on bacterial metabolism via interfacial interaction rather than nutrient supplements. Soils bearing higher amount of kaolinite and iron oxide may have greater depression on bacterial activity. The thermodynamic method provides different and complementary information to that from ...
-
adhesion of bacterial pathogens to Soil colloidal particles influences of cell type natural organic matter and solution chemistry
2014Co-Authors: Wenqiang Zhao, Qiaoyun Huang, Sharon L Walker, Peng CaiAbstract:Abstract Bacterial adhesion to granular Soil particles is well studied; however, pathogen interactions with naturally occurring colloidal particles ( Streptococcus suis SC05 and Escherichia coli WH09 over a wide range of solution pH (4.0–9.0) and ionic strength (IS, 1–100 mM KCl). Cell characterization techniques, Freundlich isotherm, and Derjaguin–Landau–Verwey–Overbeek (DLVO) theory (sphere–sphere model) were utilized to quantitatively determine the interactions between cells and Colloids. The adhesion coefficients ( K f ) of S. suis SC05 to NOM-present and NOM-stripped Soil Colloids were significantly higher than E. coli WH09, respectively. Similarly, K f values of S. suis SC05 and E. coli WH09 adhesion to NOM-stripped Soil Colloids were greater than those Colloids with NOM-present, respectively, suggesting NOM inhibits bacterial adhesion. Cell adhesion to Soil Colloids declined with increasing pH and enhanced with rising IS (1–50 mM). Interaction energy calculations indicate these adhesion trends can be explained by DLVO-type forces, with S. suis SC05 and E. coli WH09 being weakly adhered in shallow secondary energy minima via polymer bridging and charge heterogeneity. S. suis SC05 adhesion decreased at higher IS 100 mM, which is attributed to the change of hydrophobic effect and steric repulsion resulted from the greater presence of extracellular polymeric substances (EPS) on S. suis SC05 surface as compared to E. coli WH09. Hence, pathogen adhesion to the colloidal material is determined by a combination of DLVO, charge heterogeneity, hydrophobic and polymer interactions as a function of solution chemistry.
-
In situ ATR-FTIR study on the adhesion of Pseudomonas putida to Red Soil Colloids
2013Co-Authors: Wenli Chen, Xingmin Rong, Peng Cai, Ke Dai, Qiaoyun HuangAbstract:Purpose Bacterial adhesion to Soil particles is fundamentally important in mineral weathering, organic matter degradation, heavy metal transformation, and fate of pollutants. However, the adhesion mechanism between bacteria and Soil Colloids under continuous flow systems in the natural environments remains unknown.
-
conformation activity and proteolytic stability of acid phosphatase on clay minerals and Soil Colloids from an alfisol
2009Co-Authors: Qiaoyun Huang, Xingmin Rong, Peng Cai, Jun Zhu, Wei Liang, Xueqing Qiao, Wenli ChenAbstract:The present study was carried out to investigate the conformation, enzymatic activity and proteolytic stability of acid phosphatase on montmorillonite, kaolinite and Soil Colloids from an Alfisol by means of circular dichroism (CD) spectroscopy, isothermal titration microcalorimetry (ITC) and biochemical assay, respectively. The results showed that the secondary structure of phosphatase was changed from disordered type to ordered form during adsorption/desorption cycle, organic substance and 2:1-clay mineral in Brown Soil benefited the formation of ordered structure. Enzymatic activity of phosphatase was inhibited while the proteolytic stability was promoted after the interaction with active particles from permanent charge Soil. The decrease of enzymatic activity and the increase of proteolytic stability resulted by montmorillonite and organic colloid were both greater than that by kaolinite and inorganic colloid, which was in consistent with the extent of structural change induced by different colloid particles. Thus, one of the most significant factors responsible for the variation of enzymatic activity and proteolytic stability might be the hiding or even damage of active sites and the irrecognition of cleavage sites in enzyme molecules induced by the formation of ordered structure. The information obtained in this study is of crucial significance for the understanding of the behavior and fate of extracellular enzymes in Soils with permanent charges.
-
role of bacteria in the adsorption and binding of dna on Soil Colloids and minerals
2009Co-Authors: Peng Cai, Qiaoyun Huang, Jun Zhu, Linchun Fang, Wei Liang, Wenli ChenAbstract:Abstract Adsorption and desorption of salmon sperm DNA on bacteria (Bacillus thuringiensis, Pseudomonas putida), two different colloidal fractions (organic and inorganic clay) from an Alfisol, minerals (montmorillonite, kaolinite and goethite) and colloid–bacteria composites were studied. Similar adsorption capacity and affinity of DNA were observed on two bacterial cells. However, the two bacterial strains played different roles in affecting the adsorption of DNA on the composites of Soil colloidal particles with bacteria. The introduction of B. thuringiensis in Soil Colloids and minerals systems dramatically promoted DNA adsorption on colloidal particles especially organic clay, while P. putida decreased the adsorption of DNA on kaolinite and goethite. Electrostatic force and ligand exchange are regarded to be the major driving forces involved in the adsorption of DNA on bacterial cells, montmorillonite, Soil Colloids and goethite. Presence of bacteria enhanced the proportion of DNA adsorption on Soil colloidal particles by electrostatic force and depressed that by ligand exchange process. Information obtained in this study is of fundamental significance for the understanding of the ultimate fate of extracellular DNA in Soil systems.
Jun Jiang - One of the best experts on this subject based on the ideXlab platform.
-
inhibition of phosphate sorptions on four Soil Colloids by two bacteria
2021Co-Authors: Zhineng Hong, Jing Yan, Jun JiangAbstract:Abstract Ion sorption on Soil and sediment has been reported to be potentially affected by bacteria which may interact both physically and chemically with solid surfaces. However, whether and how bacteria affect the sorption of inorganic phosphate (P) on Soil Colloids remains poorly known. Here, we comparably investigated the P sorption on four Soil Colloids (three highly weathered Soils including two Oxisols and one Ultisol and one weakly weathered Soil Alfisol) and their complexes with Bacillus subtilis and Pseudomonas fluorescens. Batch experiments showed a notable reduction in P sorption on the Colloids of highly weathered Soils by the two bacteria at varying P concentrations and pHs; whereas that on the Colloids of Alfisol appeared to be unaffected by the bacteria. The inhibitory effect was confirmed by both greater decline in P sorption at higher bacteria dosages and the ability of the bacteria to desorb P pre-adsorbed on the Colloids. Further evidence was given by isothermal titration calorimetric experiments which revealed an alteration in enthalpy change caused by the bacteria for P sorption on Oxisol but not for that on Alfisol. The B. subtilis was more efficient in suppressing P sorption than the P. fluorescens, indicating a dependence of the inhibition on bacterium type. After association with bacteria, zeta potentials of the Soil Colloids decreased considerably. The decrease positively correlated with the decline in P sorption, regardless of Soil and bacterium types, demonstrating that the increment in negative charges of Soil Colloids by bacteria probably contributed to the inhibition. In addition, scanning electron microscopic observation and the Derjaguin–Landau–Verwey–Overbeek theory prediction suggested appreciable physical and chemical interactions between the bacteria and the highly weathered Soil Colloids, which might be another contributor to the inhibition. These findings expand our understandings on how bacteria mobilize legacy P in Soils and sediments.
-
direct quantification of sorption thermodynamics of phosphate on four Soil Colloids through isothermal titration calorimetry
2021Co-Authors: Zhineng Hong, Jing Yan, Jun JiangAbstract:Sorption thermodynamics of phosphate (P) on the Soil colloid remains poorly known, although many previous studies have been done by macroscopic, microscopic, and spectroscopic methods. Here, we dir...
-
interactions between escherchia coli and the Colloids of three variable charge Soils and their effects on Soil surface charge properties
2015Co-Authors: Zhineng Hong, Jun Jiang, Jiuyu Li, Ren-kou XuAbstract:The adhesion of Escherchia coli (E. coli) to the Colloids of three variable charge Soils and its effect on surface charge properties and potassium adsorption of these Soil Colloids were investigated. The adhesion isotherms of E. coli by Soil Colloids can be described using the Langmuir equation. The amount of E. coli adhered by the Soil Colloids varied with Soil type and followed the order: Ultisol from Guangxi > Oxisol from Yunnan > Ultisol from Jiangxi. The iron and aluminum oxide contents and CECs of the Soils are the important factors affecting the adhesion of E. coli to Soil Colloids. The relatively lower iron and aluminum oxide contents and higher CEC of the Ultisol from Jiangxi led to the lower adhesion of E. coli to the Soil Colloids compared to the Ultisol from Guangxi and the Oxisol from Yunnan. The amount of E. coli adhered to the Soil Colloids decreased with increasing pH, which was consistent with the results predicted from the DLVO theory. E. coli adhesion made the zeta potential of the Soil...
-
interactions between escherchia coli and the Colloids of three variable charge Soils and their effects on Soil surface charge properties
2015Co-Authors: Zhaodong Liu, Zhineng Hong, Jun JiangAbstract:The adhesion of Escherchia coli (E. coli) to the Colloids of three variable charge Soils and its effect on surface charge properties and potassium adsorption of these Soil Colloids were investigated. The adhesion isotherms of E. coli by Soil Colloids can be described using the Langmuir equation. The amount of E. coli adhered by the Soil Colloids varied with Soil type and followed the order: Ultisol from Guangxi > Oxisol from Yunnan > Ultisol from Jiangxi. The iron and aluminum oxide contents and CECs of the Soils are the important factors affecting the adhesion of E. coli to Soil Colloids. The relatively lower iron and aluminum oxide contents and higher CEC of the Ultisol from Jiangxi led to the lower adhesion of E. coli to the Soil Colloids compared to the Ultisol from Guangxi and the Oxisol from Yunnan. The amount of E. coli adhered to the Soil Colloids decreased with increasing pH, which was consistent with the results predicted from the DLVO theory. E. coli adhesion made the zeta potential of the Soil...
-
the mechanism of chromate sorption by three variable charge Soils
2008Co-Authors: Jun Jiang, Ren-kou Xu, Yong Wang, Anzhen ZhaoAbstract:Abstract Adsorption of chromate and desorption of the pre-adsorbed chromate were studied using three representative variable charge Soils from the south of China. The mechanisms of the adsorption were discussed based on the hydroxyl release and the change of ζ potential during the chromate adsorption. The adsorption and desorption of chromate followed the same order: the Hyper-Rhodic Ferralsol > the Rhodic Ferralsol > the Haplic Acrisol. The adsorption and the desorption both increased with elevation of the equilibrium chromate concentration and decreased with increasing of the Soil solution pH. The percentage of the specific adsorption of chromate was 54.0–59.4%, 54.3–60.3%, and 43.9–46.2% for the Hyper-Rhodic Ferralsol, the Rhodic Ferralsol, and the Haplic Acrisol, respectively; the percentage of the electrostatic adsorption was 40.0–46.6%, 39.7–45.8%, and 50.8–56.5% for the three Soils, respectively. These findings suggest that both the specific adsorption and the electrostatic adsorption contributed to the chromate adsorption by the variable charge Soils. The hydroxyl release during the chromate adsorption shared the same trend with the adsorption envelopes, and decreased with increasing of pH. This is attributed to the exchange of chromate with the hydroxyl on the Soil particle surfaces and the formation of a chemical bond between chromate and the surface. Our results indicate that the adsorption of chromate resulted in a shift of ζ potential-pH curves of the Soil Colloids to negative values, which suggests that the adsorption increased the negative surface charge and decreased the surface potential of the Soil Colloids.