Effects of fulvic acid on growth performance and intestinal health of juvenile loach Paramisgurnus dabryanus (Sauvage).

PubMed

Gao, Yang; He, Jie; He, Zhuliu; Li, Zhiwei; Zhao, Bo; Mu, Yi; Lee, Jeong-Yeol; Chu, Zhangjie

2017-03-01

A 60-day feeding trial was conducted to determine the effect of dietary fulvic acid supplements on intestinal digestive activity (enzymatic analysis), antioxidant activity, immune enzyme activity and microflora composition of juvenile loach (initial weight of 6.2 ± 0.1 g) reared in experimental aquaria. Five test diets containing 0, 0.5, 1.0, 1.5, and 2% fulvic acid were randomly assigned to three aquaria, respectively. Elevated growth performance including final weight, weight gain (WG), specific growth rate (SGR) and feed conversion ratio (FCR) was observed in loaches that were fed fulvic acid. Maximal weight gain rates and specific growth rates occurred at the 1.5% additive level. The optimal dietary fulvic requirement for maximal growth of juvenile loach is 16.4 g per kg of the diet based on the quadratic regression analysis of specific growth rate against dietary fulvic acid levels. Furthermore, intestinal protease activity, antioxidant activity, lysozyme activity (LZM), complement 3 (C3) content, immunoglobulin M (IgM) content, acid phosphatase activity (ACP) and alkaline phosphatase activity (AKP) were significantly elevated with concomitant increasing levels of dietary fulvic acid. Following a deep sequencing analysis, a total of 42,058 valid reads and 609 OTUs (operational taxonomic units) obtained from the control group and the group displaying the most optimal growth rate were analyzed. Fulvic acid supplementation resulted in an abundance of Firmicute and Actinobacteria sequences, with a concomitant reduction in the abundance of Proteobacteria. Results indicated that fulvic acid supplementation resulted in a reduction in the relative abundance of Serratia, Acinetobacter, Aeromonas and Edwardsiella, and a relative increase in the abundance of Lactobacillus in the intestine. In conclusion, these results suggest that fulvic acid improves growth performance and intestinal health condition of loach, indicates that fulvic acid could be used as an

Nitrosation and nitration of fulvic acid, peat and coal with nitric acid

USGS Publications Warehouse

Thorn, Kevin A.; Cox, Larry G.

2016-01-01

Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples.

Nitrosation and Nitration of Fulvic Acid, Peat and Coal with Nitric Acid

PubMed Central

Thorn, Kevin A.; Cox, Larry G.

2016-01-01

Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples. PMID:27175784

Effect of fulvic acids on the electrolytes physiology in vertebrates

NASA Astrophysics Data System (ADS)

Morales, O. Y.; Navarrete, J. M.; Gracia, I.; Macias, L.; Rivera, M.; Sanchez, F.

2011-10-01

Fulvic acids are the active principle in humus fertilizers which are the cause of better absorption of mineral ions from soil to plant tissues. Tested in mice by making use of radioactive labeled ions, they showed their action of enhancing by a factor greater than two the filtration through liver of PO 43- and Ca 2+ from digestive tract to blood serum as well as through kidney from blood serum to urine. Following this research, Fe 3+ and I 1- ions labeled with 59Fe and 131I have been tested and reported in the present paper. Results showed that iron ions are completely fixed in red cells, with no residue eliminated by urine, while iodine ions are fixed in thyroid gland, with some residue eliminated by urine. Both ions were fixed in said tissues by factors larger than two when they are escorted by fulvic acids. A general distribution of these ions in blood, urine, feces, liver, kidney and thyroid gland has been surveyed, trying to find the earliest effect of fulvic acids in the physiology of vertebrates.

Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials: a review.

PubMed

Tang, Wang-Wang; Zeng, Guang-Ming; Gong, Ji-Lai; Liang, Jie; Xu, Piao; Zhang, Chang; Huang, Bin-Bin

2014-01-15

Nowadays nanomaterials have been widely used to remove heavy metals from water/wastewater due to their large surface area and high reactivity. Humic acid (HA) and fulvic acid (FA) exist ubiquitously in aquatic environments and have a variety of functional groups which allow them to complex with metal ions and interact with nanomaterials. These interactions can not only alter the environmental behavior of nanomaterials, but also influence the removal and transportation of heavy metals by nanomaterials. Thus, the interactions and the underlying mechanisms involved warrant specific investigations. This review outlined the effects of HA/FA on the removal of heavy metals from aqueous solutions by various nanomaterials, mainly including carbon-based nanomaterials, iron-based nanomaterials and photocatalytic nanomaterials. Moreover, mechanisms involved in the interactions were discussed and potential environmental implications of HA/FA to nanomaterials and heavy metals were evaluated. © 2013.

Effect of fulvic and humic acids on copper and zinc homeostasis in rats.

PubMed

Hullár, István; Vucskits, András Valentin; Berta, Erzsébet; Andrásofszky, Emese; Bersényi, András; Szabó, József

2018-03-01

The objective of this study was to investigate the effects of fulvic acid (FA) and humic acid (HA), the two main compounds of humic substances (HSs), on copper (Cu) and zinc (Zn) homeostasis. Seventy-two male Wistar rats were randomly divided into nine experimental groups. The control diet (AIN-93G formula) and the diets supplemented with 0.1%, 0.2%, 0.4% and 0.8% FA or HA were fed for 26 days. Cu and Zn concentrations of the large intestinal content (LIC), liver, kidney, femur and hair were determined. FA and HA did not influence significantly the Cu or Zn contents of the experimental diets, the rats' feed intake, weight gain and the feed to gain ratio. Both FA and HA decreased the Cu concentrations of the LIC significantly and in a dose-related manner; however the absorption-stimulating effect of HA was more pronounced. FA increased the Cu content of the liver, but neither FA nor HA had a dose-dependent effect on it. FA or HA supplementations had no significant effect on the Cu concentration of the kidney. At the concentrations used, dietary FA or HA supplementations are not promising growth promoters. FA influences the Cu homeostasis unlike HA, because FA not only stimulates Cu absorption, but the extra quantity of absorbed Cu is retained in the organism. The stimulatory effect of HA on Zn absorption may not be manifested in Cu and Zn homeostasis, because of the tight connection of these microelements to FA and HA, which prevents the transmission of Zn from the ZnHA complex to the organs. As regards the effect of FA and HA on Cu and Zn homeostasis, both FA and HA stimulated the absorption of these microelements, but only FA increased the retention of Cu (in the liver) and Zn (in the kidney).

Fulvic Acid Mediated Photolysis of Ibuprofen in Water.

EPA Science Inventory

Photolysis of the nonsteroidal anti-inflammatory drug ibuprofen was studied in solutions of fulvic acid (FA) isolated from Pony Lake, Antarctica; Suwannee River, GA, USA; and Old Woman Creek, OH, USA. At an initial concentration of 10 µM ibuprofen degrades by direct photolysis...

The effect of sample hydration on 13C CPMAS NMR spectra of fulvic acids

USGS Publications Warehouse

Hatcher, P.G.; Wilson, M.A.

1991-01-01

Three fulvic acids, two of which have been well studied by a number of other groups (Armadale and Suwannee river fulvic acids) have been examined by high resolution solid-state 13C-NMR techniques to delineate the effect of absorbed water. Two main effects of absorbed water were observed: (1) changes in spin lattice relaxation times in the rotating frame and cross polarization times and (2) total loss of signal so that some fulvic acid is effectively in solution. These results suggest that discrepancies in the literature concerning observed relative signal intensities from different structural groups are due to absorbed water and emphasize the necessity for proper precautionary drying before spectroscopic analysis. ?? 1991.

Enzymatic coupling of 2,4-dichlorophenol to stream fulvic acid in the presence of oxidoreductases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarkar, J.M.; Malcolm, R.L.; Bollag, J.M.

The coupling {sup 14}C-ring-labelled 2,4-dichlorophenol (2,4-DCP) to stream fulvic acid was investigated in the presence of several oxidoreductases including tyrosinase, peroxidase, and laccases of Rhizoctonia praticola and Trametes vesicolor. During 12-h incubation of the oxidoreductases with {sup 14}C-2, 4-DCP and stream fulvic acid, a substantial amount of the radioactivity was incorporated into fulvic acid. Chromatographic analysis indicated that although a large portion of the radioactivity remained in solution, no unbound {sup 14}C-2,4-DCP was present in the supernatant. The effects of pH, temperature, concentration of fulvic acid, and concentration of enzyme on the coupling processes were studied. The results of thismore » research provide evidence that the enzymatic coupling of certain xenobiotic pollutants to humic substances is an important natural process which must be considered in studies of the fate, reactivity, and persistence of these organic compounds in soils and stream waters.« less

Fluorescence analysis of humic and fulvic acids from two Brazilian oxisols as affected by biosolid amendment.

PubMed

Bertoncini, E I; D'Orazio, V; Senesi, N; Mattiazzo, M E

2005-03-01

Conventional monodimensional fluorescence spectroscopy in the emission, excitation, and synchronous-scan modes and total luminescence spectroscopy have proven to be sensitive techniques for characterization and differentiation of humic acid (HA) and fulvic acid (FA) fractions isolated from an aerobically and anaerobically digested and limed biosolid, two layers of a sandy and a clayey Brazilian oxisol, and the corresponding biosolid-amended soils. The spectral patterns and the relative fluorescence intensities suggest greater molecular heterogeneity, less aromatic polycondensation, and less humification of biosolid HA and FA compared with soil HA and FA. However, the differences are smaller for the FA fractions than for the HA fractions. Fluorescence properties of soil HA and FA differ slightly as a function of soil type and soil layer. Biosolid application causes a shift to shorter wavelengths of the main fluorescence peaks and marked variation of the relative fluorescence intensities of HA and FA isolated from amended soils. These results suggest that molecular components of relatively small molecular size, with a low level of aromatic polycondensation, and low degree of humification present in biosolid HA and FA are partially and variously incorporated into amended soil HA and FA. In general, these modifications seem to be smaller in HA and FA from the clayey soil layers than in those from the sandy soil layers, possibly because of protective effects exerted by clay minerals of native soil HA and FA against disturbances caused by biosolid application.

Change of physical and chemical parameters of fulvic acids at different pH of the system

NASA Astrophysics Data System (ADS)

Dinu, Marina; Kremleva, Tatyana

2017-04-01

Organic substances of humic nature significantly change physicochemical properties at different pH of natural waters. As a consequence, a large number of consecutive and parallel reactions in the structure of organic polymers, and reacting with inorganic anions. The main indicators of changes in the properties of organic acids in natural systems are changes in their IR spectra, changes in the colloid stability (the zeta potential) as well as in the molecular weight and emission spectra (fluorescence emission spectra). The aim of our study was to evaluate of changing in physical and chemical properties of the fulvic acid from soil/water samples in the natural areas of European Russia and Western Siberia (the steppe and the northern taiga zones) at different pH (from 8 to 1.5). Changes in absorption bands of fulvic acid caused by both COOH groups and amino groups with varying degrees of protonation were found. Consequently, we can assume that in an electric field fulvic acid change the sign of their charge at depending on pH. During the lowering of the pH intensity of C-O bands generally decreases, while in the region 1590 cm-1 disappears. In turn, the band at 1700 cm-1 is the most intense; it could mean a complete protonation of the carboxyl groups. According to our data, the values of zeta potential changes depending on pH of the system. The zeta potential becomes more negative with increasing pH and it may be due to ionization of oxygen groups of fulvic acid. For the colloidal polymer systems the value of the zeta potential is strongly negative (less than -20 mV) and strongly positive (over 20 mV) characterize the system as the most stable. Our experimental data for the study of the zeta potential of fulvic acids extracted from the soils and waters of different climatic zones show zonal influence of the qualitative characteristics of organic substances on the surface charge of the high-molecular micelle of fulvic acids. It was found that fulvic acids extracted

The impact of humic and fulvic acids on the dynamic properties of liposome membranes: the ESR method.

PubMed

Man, Dariusz; Pisarek, Izabella; Braczkowski, Michał; Pytel, Barbara; Olchawa, Ryszard

2014-06-01

This paper presents the results of research on the influence of two fractions of humic substances (HS): fulvic acids (FA) and humic acids (HA), as a function of concentration, on the liposome membranes formed from egg yolk lecithin (EYL). The concentration of HS in relation to EYL changed from 0% to 10% by weight. The influence of HS on various areas of membranes: interphase water-lipid, in the lipid layer just below the polar part of the membrane and in the middle of the lipid bilayer, was investigated by different spin labels (TEMPO, DOXYL 5, DOXYL 16). The study showed that HA slightly decreased the fluidity of the analyzed membranes on the surface layer, while FA significantly liquidated the center of the lipid bilayer. The strong effect of both fractions of HS on the concentration of free radicals as a function of time was also described.

Effect of fulvic and humic acids on iron and manganese homeostasis in rats.

PubMed

Szabó, József; Vucskits, András Valentin; Berta, Erzsébet; Andrásofszky, Emese; Bersényi, András; Hullár, István

2017-03-01

The objective of this study was to investigate the effects of fulvic acid (FA) and humic acid (HA) as the two main compounds of humic substances, separately on Fe and Mn homeostasis. Seventy-two male Wistar rats were randomly divided into 9 experimental groups. The control diet (AIN-93G formula) and diets supplemented with 0.1%, 0.2%, 0.4% and 0.8% HA or FA were fed for 26 days. Fe and Mn concentrations of the large intestinal content, liver, kidney, femur and hair were determined. No significant differences were observed in the production parameters. The effects of FA and HA on iron homeostasis were significantly different. FA proved to be a good iron source, and slightly increased the iron content of liver and kidney, but - up to a dietary iron level of 52.7 mg/kg - it did not influence the efficiency of iron absorption. Above a dietary iron level of 52.7 mg/kg down-regulation of Fe absorption can be assumed. HA significantly stimulated the iron uptake and there was no down-regulation of Fe absorption up to 0.8% dietary HA supplementation level (61.5 mg Fe/kg diet). In the HA groups the iron content of the liver and kidney decreased significantly, suggesting that in spite of the better Fe absorption, the HA-Fe complex does not provide iron to the investigated organs. Neither FA nor HA supplementation influenced the Fe content of the femur and hair and slightly decreased the Mn concentration in the large intestinal content. This effect was significant (with a 22.7% Mn concentration decrease) only at the HA supplementation rate of 0.8%. Neither FA nor HA influenced significantly the Mn concentrations of the liver, kidney and femur. The Mn concentration of the hair in rats receiving FA- or HA-supplemented diets was higher than in the control rats; however, this result needs further confirmation.

Hyporheic exchange and fulvic acid redox reactions in an alpine stream/wetland ecosystem, Colorado front range

USGS Publications Warehouse

Miller, Matthew P.; McKnight, Diane M.; Cory, R.M.; Williams, Mark W.; Runkel, Robert L.

2006-01-01

The influence of hyporheic zone interactions on the redox state of fulvic acids and other redox active species was investigated in an alpine stream and adjacent wetland, which is a more reducing environment. A tracer injection experiment using bromide (Br-) was conducted in the stream system. Simulations with a transport model showed that rates of exchange between the stream and hyporheic zone were rapid (?? ??? 10-3 s -1). Parallel factor analysis of fluorescence spectra was used to quantify the redox state of dissolved fulvic acids. The rate coefficient for oxidation of reduced fulvic acids (?? = 6.5 ?? 10-3 s -1) in the stream indicates that electron-transfer reactions occur over short time scales. The rate coefficients for decay of ammonium (?? = 1.2 ?? 10-3 s-1) and production of nitrate (?? = -1.0 ?? 10-3 s-1) were opposite in sign but almost equal in magnitude. Our results suggest that fulvic acids are involved in rapid electron-transfer processes in and near the stream channel and may be important in determining ecological energy flow at the catchment scale. ?? 2006 American Chemical Society.

Molecular resolution and fragmentation of fulvic acid by electrospray ionization/multistage tandem mass spectrometry

USGS Publications Warehouse

Leenheer, J.A.; Rostad, C.E.; Gates, Paul M.; Furlong, E.T.; Ferrer, I.

2001-01-01

Molecular weight distributions of fulvic acid from the Suwannee River, Georgia, were investigated by electrospray ionization/quadrupole mass spectrometry (ESI/QMS), and fragmentation pathways of specific fulvic acid masses were investigated by electrospray ionization/ion trap multistage tandem mass spectrometry (ESI/MST/MS). ESI/QMS studies of the free acid form of low molecular weight poly(carboxylic acid) standards in 75% methanol/25% water mobile phase found that negative ion detection gave the optimum generation of parent ions that can be used for molecular weight determinations. However, experiments with poly(acrylic acid) mixtures and specific high molecular weight standards found multiply charged negative ions that gave a low bias to molecular mass distributions. The number of negative charges on a molecule is dependent on the distance between charges. ESI/MST/MS of model compounds found characteristic water loss from alcohol dehydration and anhydride formation, as well as CO2 loss from decarboxylation, and CO loss from ester structures. Application of these fragmentation pathways to specific masses of fulvic acid isolated and fragmented by ESI/MST/MS is indicative of specific structures that can serve as a basis for future structural confirmation after these hypothesized structures are synthesized.

A log-normal distribution model for the molecular weight of aquatic fulvic acids

USGS Publications Warehouse

Cabaniss, S.E.; Zhou, Q.; Maurice, P.A.; Chin, Y.-P.; Aiken, G.R.

2000-01-01

The molecular weight of humic substances influences their proton and metal binding, organic pollutant partitioning, adsorption onto minerals and activated carbon, and behavior during water treatment. We propose a lognormal model for the molecular weight distribution in aquatic fulvic acids to provide a conceptual framework for studying these size effects. The normal curve mean and standard deviation are readily calculated from measured M(n) and M(w) and vary from 2.7 to 3 for the means and from 0.28 to 0.37 for the standard deviations for typical aquatic fulvic acids. The model is consistent with several types of molecular weight data, including the shapes of high- pressure size-exclusion chromatography (HP-SEC) peaks. Applications of the model to electrostatic interactions, pollutant solubilization, and adsorption are explored in illustrative calculations.The molecular weight of humic substances influences their proton and metal binding, organic pollutant partitioning, adsorption onto minerals and activated carbon, and behavior during water treatment. We propose a log-normal model for the molecular weight distribution in aquatic fulvic acids to provide a conceptual framework for studying these size effects. The normal curve mean and standard deviation are readily calculated from measured Mn and Mw and vary from 2.7 to 3 for the means and from 0.28 to 0.37 for the standard deviations for typical aquatic fulvic acids. The model is consistent with several type's of molecular weight data, including the shapes of high-pressure size-exclusion chromatography (HP-SEC) peaks. Applications of the model to electrostatic interactions, pollutant solubilization, and adsorption are explored in illustrative calculations.

Sorption of Eu(III) on humic acid or fulvic acid bound to hydrous alumina studied by SEM-EDS, XPS, TRLFS, and batch techniques.

PubMed

Tan, X L; Wang, X K; Geckeis, H; Rabung, Th

2008-09-01

To identify the effect of humic acid (HA) and fulvic acid (FA) on the sorption mechanism of Eu(III) on organic--inorganic colloids in the environment at a molecular level, surface adsorbed/ complexed Eu(III) on hydrous alumina, HA-, and FA-hydrous alumina hybrids were characterized by using X-ray photoelectron spectroscopy (XPS) and time-resolved laser fluorescence spectroscopy (TRLFS). The experiments were performed in 0.1 mol/L KNO3 or 0.1 mol/L NaClO4 under ambient conditions. The pH values were varied between 2 and 11 at a fixed Eu(III) concentration of 6.0 x 10(-7) mol/L and 4.3 x 10(-5) mol/L. The different Eu(III)/FA(HA)/hydrous alumina complexes were characterized by their fluorescence emission spectra ((5D0-F1)/ (5D0 --> 7F2)) and binding energy of Eu(III). Inner-sphere surface complexation may contribute mainly to Eu(III) sorption on hydrous alumina, and a ternary surface complex is formed at the HA/ FA-hydrous alumina hybrid surfaces. The sorption and species of Eu(III) in ternary Eu-HA/FA-hydrous alumina systems are not dominated by either HA/FA or hydrous alumina, but are dominated by both HA/FA and hydrous alumina. The results are important for understanding the sorption mechanisms and the nature of surface adsorbed Eu(III) species and trivalent chemical homologues of Eu(III) in the natural environment.

13C-NMR spectra and contact time experiment for Skjervatjern fulvic and humic acids

USGS Publications Warehouse

Malcolm, R.L.

1992-01-01

The T(CP) and T(1p) time constants for Skjervatjern fulvic and humic acids were determined to be short with T(CP) values ranging from 0.14 ms to 0.53 ms and T(1p) values ranging from 3.3 ms to 5.9 ms. T(CP) or T(1p) time constants at a contact time of 1 ms are favorable for quantification of 13C-NMR spectra. Because of the short T(CP) values, correction factors for signal intensity for various regions of the 13C-NMR spectra would be necessary at contact times greater than 1.1 ms or less than 0.9 ms. T(CP) and T(1p) values have a limited non-homogeneity within Skjervatjern fulvic and humic acids. A pulse delay or repeat time of 700 ms is more than adequate for quantification of these 13C-NMR spectra. Paramagnetic effects in these humic substances are precluded due to low inorganic ash contents, low contents of Fe, Mn, and Co, and low organic free-radical contents. The observed T(CP) values suggest that all the carbon types in Skjervatjern fulvic and humic acids are fully cross-polarized before significant proton relaxation occurs. The 13C-NMR spectra for Skjervatjern fulvic acid is similar to most aquatic fulvic acids as it is predominantly aliphatic, low in aromaticity (fa1 = 24), low in phenolic content, high in carboxyl content, and has no resolution of a methoxyl peak. The 13C-NMR spectra for Skjervatjern humic acid is also similar to most other aquatic humic acids in that it is also predominantly aliphatic, high in aromaticity (fa1 = 38), moderate in phenolic content, moderate in carboxyl content, and has a clear resolution of a methoxyl carbon region. After the consideration of the necessary 13C-NMR experimental conditions, these spectra are considered to be quantitative. With careful consideration of the previously determined 13C-NMR experimental conditions, quantitative spectra can be obtained for humic substances in the future from the HUMEX site. Possible changes in humic substances due to acidification should be determined from 13C-NMR data.

Adsorption characterizations of fulvic acid fractions onto kaolinite.

PubMed

Li, Aimin; Xu, Minjuan; Li, Wenhui; Wang, Xuejun; Dai, Jingyu

2008-01-01

Fulvic acids extracted from a typical rice-production region near Taihu Lake of China were fractionated into three fractions including F4.8, F7.0 and F11.0 (eluted by pH 4.8 buffer, pH 7.0 buffer and pH 11.0 buffer, respectively). Sorption of fulvic acid (FA) fractions onto kaolinite was studied by batch adsorption experiments, and characterizations of kaolinite before and after adsorption were investigated using scanning electron microscopy (SEM). Adsorption isotherms of kaolinite for three FA fractions fit well with the Langmuir adsorption model. The adsorption density of the three fractions was positively correlated with the ratio of the amount of the alkyl carbon to that of carboxyl and carbonyl carbon in FA fractions and followed an order of F11.0 > F7.0 > F4.8. Hydrophobic interaction was one of the control mechanisms for the sorption of FA fraction onto kaolinite. SEM images confirmed that compared to blank kaolinite samples, kaolinite samples coated by a FA fraction displayed an opener and more dispersed conformation resulting from the disruption of the floc structure in complex. Dispersion of kaolinite after adsorption was due to the repulsion between negatively charged FA-coated particles, which is closely related to the amount of FA fractions absorbed on kaolinite.

Mechanistic study of fulvic acid assisted propranolol photodegradation in aqueous solution.

PubMed

Makunina, Maria P; Pozdnyakov, Ivan P; Chen, Yong; Grivin, Vyacheslav P; Bazhin, Nikolay M; Plyusnin, Victor F

2015-01-01

Laser flash (355 nm) and stationary (365 nm) photolysis were used to study the mechanisms of propranolol photolysis in the presence of fulvic acid in aqueous solutions. The FA-assisted photodegradation of propranolol was observed using UV-A irradiation (where propranolol is stable). Direct evidence indicated that the photodegradation resulted from the static quenching of the FA triplet state by propranolol via the electron transfer mechanism. The triplet state yield (ϕT≈0.6%) and the T-T absorption coefficient (ɛT(620 nm)≈5×10(4) M(-1) cm(-1)) were estimated for the first time by modeling the yields of the FA triplet state in the presence of propranolol. Thus, fulvic acid is a promising agent for accelerating propranolol photodegradation in aqueous solutions under UV-A light irradiation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Computational scheme for the prediction of metal ion binding by a soil fulvic acid

USGS Publications Warehouse

Marinsky, J.A.; Reddy, M.M.; Ephraim, J.H.; Mathuthu, A.S.

1995-01-01

The dissociation and metal ion binding properties of a soil fulvic acid have been characterized. Information thus gained was used to compensate for salt and site heterogeneity effects in metal ion complexation by the fulvic acid. An earlier computational scheme has been modified by incorporating an additional step which improves the accuracy of metal ion speciation estimates. An algorithm is employed for the prediction of metal ion binding by organic acid constituents of natural waters (once the organic acid is characterized in terms of functional group identity and abundance). The approach discussed here, currently used with a spreadsheet program on a personal computer, is conceptually envisaged to be compatible with computer programs available for ion binding by inorganic ligands in natural waters.

Application of INEPT nitrogen-15 and silicon-29 nuclear magnetic resonance spectrometry to derivatized fulvic acids

USGS Publications Warehouse

Thorn, K.A.; Folan, D.W.; Arterburn, J.B.; Mikita, M.A.; MacCarthy, P.

1989-01-01

Use of the INEPT experiment has been examined in two derivatization studies of the Suwannee River fulvic acid. In the first study, the fulvic acid was derivatized with 15N enriched hydroxylamine. The quantitative 15N NMR spectrum, acquired with a 45° pulse angle, 2.0 second pulse delay and inverse gated decoupling, showed that oximes (390-340 ppm) were the major derivatives, followed by nitriles (270-240 ppm), hydroxamic acids (170-160 ppm), secondary amides (150-115 ppm), and lactams (115-90 ppm). The INEPT 15N NMR spectrum was acquired using refocussing delays and polarization transfer times optimized for signal enhancement of singly protonated nitrogens. INEPT greatly enhanced the amide and lactam resonances, and showed that resonances downfield of 180 ppm in the quantitative spectrum represented nonprotonated nitrogens. In the second study, the fulvic acid was first methylated with diazomethane and then silylated with hexamethyldisilazane. The 29Si NMR spectra exhibited two major peaks, from approximately 33 to 22 ppm, representing silyl esters of carboxylic acids, and from 22 to 13 ppm, representing silyl ethers of alcohols and phenols. The INEPT 29Si NMR spectrum was virtually identical to the quantitative 29Si spectrum, acquired with a 90° pulse angle, 5.0 second pulse delay, inverse gated decoupling, and relaxation reagent. INEPT therefore can be used for quantitative analysis of trimethylsilyl derivatives of the fulvic acid, saving spectrometer time and eliminating the need for relaxation reagents.

DYNAMIC CONDUCTIVITY MEASUREMENTS IN HUMIC AND FULVIC ACID SOLUTIONS. (R828158)

EPA Science Inventory

Conductivity changes of dilute aqueous humic and fulvic acids solutions were monitored after the addition of small quantities of Cu, Cd, Pb, and Zn. The solutions were stirred at a constant and reproducible rate, and measurements proceeded until stable conductivities were atta...

Vapor-pressure osmometric study of the molecular weight and aggregation tendency of a reference-soil fulvic acid

USGS Publications Warehouse

Marinsky, J.A.; Reddy, M.M.

1990-01-01

The molecular weight and aggregation tendency of a reference-soil fulvic acid in Armadale horizon Bh were determined by vapor-pressure osmometry using tetrahydrofuran and water as solvents. With tetrahydrofuran, number-average molecular weight values of 767 ?? 34 and 699 ?? 8 daltons were obtained from two separate sets of measurements. Two sets of measurements with water also yielded values within this range (754 ?? 70 daltons) provided that the fulvic acid concentration in water did not exceed 7 mg ml-1; at higher concentrations (9.1-13.7 mg ml-1) a number-average molecular weight of 956 ?? 25 daltons was resolved, providing evidence of molecular aggregation. Extension of these studies to 80% neutralized fulvic acid showed that a sizeable fraction of the sodium counter ion is not osmotically active.

Speciation of sulfur in humic and fulvic acids using X-ray absorption near-edge structure (XANES) spectroscopy

NASA Astrophysics Data System (ADS)

Morra, Matthew J.; Fendorf, Scott E.; Brown, Paul D.

1997-02-01

Sulfur species in soils and sediments have previously been determined indirectly using destructive techniques. A direct and more accurate method for S speciation would improve our understanding of S biogeochemistry. X-ray absorption near edge structure (XANES) spectroscopy was performed on purified humic and fulvic acids from terrestrial and aquatic environments. This methodology allows direct determination of S species using the relationship that exists with the energy required for core electron transitions and in some cases, correlation with additional spectral features. Soil, peat, and aquatic humic acids were dominated by sulfonates with an oxidation state of +5, but also contained ester-bonded sulfates with an oxidation state of +6. Leonardite humic acid contained ester-bonded sulfate and an unidentified S compound with an oxidation state of +4.0. In contrast, high-valent S in soil, peat, and aquatic fulvic acids was exclusively in the form of sulfonic acids. Reduced S species were also present in both humic and fulvic acids. XANES is a valuable method for the speciation of S in humic materials and of potential use in S speciation of unfractionated soils.

Effect of soil humic and fulvic acids, pH and ionic strength on Th(IV) sorption to TiO2 nanoparticles.

PubMed

Tan, Xiaoli; Wang, Xiangke; Chen, Changlun; Sun, Aihua

2007-04-01

Thorium is considered as a chemical analog of other tetravalent actinides. Herein, the sorption of Th(IV) on TiO(2) in the presence or absence of soil fulvic acid (FA)/humic acid (HA) as a function of pH, ionic strength and FA/HA concentration has been studied by a batch method. The morphology was characterized by scanning electron microscopy (SEM). The results indicate that sorption of Th(IV) on TiO(2) increases from 0% to approximately 94% at pH 1 approximately 4, and then maintains level with increasing pH values. Both FA and HA have a positive effect on Th(IV) sorption at low pH values and the contribution of FA on Th(IV) sorption is rather higher than that of HA at pH<4. The sorption is weakly dependent on the concentration of KNO(3) in solution, but the cations K(+), Na(+) and Li(+) influence Th(IV) sorption more obviously. The batch results indicate that the inner sphere complex formation is formed at bare surfaces or FA/HA-bound TiO(2) particle surfaces. Results of SEM analysis show that the particle sizes of TiO(2), Th-TiO(2) and Th-HA-TiO(2) colloids are quite different. Surface complexation may be considered as the main sorption mechanism.

Models of metal binding structures in fulvic acid from the Suwannee River, Georgia

USGS Publications Warehouse

Leenheer, J.A.; Brown, G.K.; MacCarthy, P.; Cabaniss, S.E.

1998-01-01

Fulvic acid, isolated from the Suwannee River, Georgia, was assessed for its ability to bind Ca2+, Cd2+, Cu2+, Ni2+, and Zn2+ ions at pH 6 before and after extensive fractionation that was designed to reveal the nature of metal binding functional groups. The binding constant for Ca2+ ion had the greatest increase of all the ions in a metal binding fraction that was selected for intensive characterization for the purpose of building quantitative average model structures. The 'metal binding' fraction was characterized by quantitative 13C NMR, 1H NMR, and FT-1R spectrometry and elemental, titrimetric, and molecular weight determinations. The characterization data revealed that carboxyl groups were clustered in short- chain aliphatic dibasic acid structures. The Ca2+ binding data suggested that ether-substituted oxysuccinic acid structures are good models for the metal binding sites at pH 6. Structural models were derived based upon oxidation and photolytic rearrangements of cutin, lignin, and tannin precursors. These structural models rich in substituted dibasic acid structures revealed polydentate binding sites with the potential for both inner-sphere and outer-sphere type binding. The majority of the fulvic acid molecule was involved with metal binding rather than a small substructural unit.Fulvic acid, isolated from the Suwannee River, Georgia, was assessed for its ability to bind Ca2+, Cd2+, Cu2+, Ni2+, and Zn2+ ions at pH 6 before and after extensive fractionation that was designed to reveal the nature of metal binding functional groups. The binding constant for Ca2+ ion had the greatest increase of all the ions in a metal binding fraction that was selected for intensive characterization for the purpose of building quantitative average model structures. The `metal binding' fraction was characterized by quantitative 13C NMR, 1H NMR, and FT-IR spectrometry and elemental, titrimetric, and molecular weight determinations. The characterization data revealed that

Water solubility enhancement of some organic pollutants and pesticides by dissolved humic and fulvic acids

USGS Publications Warehouse

Chiou, C.T.; Malcolm, R.L.; Brinton, T.I.; Kile, D.E.

1986-01-01

Water solubility enhancements by dissolved humic and fulvic acids from soil and aquatic origins and by synthetic organic polymers have been determined for selected organic pollutants and pesticides (p,p???-DDT, 2,4,5,2???,5???-PCB, 2,4,4???-PCB, 1,2,3-trichlorobenzene, and lindane). Significant solubility enhancements of relatively water-insoluble solutes by dissolved organic matter (DOM) of soil and aquatic origins may be described in terms of a partition-like interaction of the the solutes with the microscopic organic environment of the high-molecular-weight DOM species; the apparent solute solubilities increase linearly with DOM concentration and show no competitive effect between solutes. With a given DOM sample, the solute partition coefficient (Kdom) increases with a decrease of solute solubility (Sw) or with an increase of the solute's octanol-water partition coefficient (Kow). The Kdom values of solutes with soil-derived humic acid are approximately 4 times greater than with soil fulvic acid and 5-7 times greater than with aquatic humic and fulvic acids. The effectiveness of DOM in enhancing solute solubility appears to be largely controlled by the DOM molecular size and polarity. The relative inability of high-molecular-weight poly(acrylic acids) to enhance solute solubility is attributed to their high polarities and extended chain structures that do not permit the formation of a sizable intramolecular nonpolar environment.

Factors that affect molecular weight distribution of Suwannee river fulvic acid as determined by electrospray ionization/mass spectrometry

USGS Publications Warehouse

Rostad, Colleen E.; Leenheer, Jerry A.

2004-01-01

Effects of methylation, molar response, multiple charging, solvents, and positive and negative ionization on molecular weight distributions of aquatic fulvic acid were investigated by electrospray ionization/mass spectrometry. After preliminary analysis by positive and negative modes, samples and mixtures of standards were derivatized by methylation to minimize ionization sites and reanalyzed.Positive ionization was less effective and produced more complex spectra than negative ionization. Ionization in methanol/water produced greater response than in acetonitrile/water. Molar response varied widely for the selected free acid standards when analyzed individually and in a mixture, but after methylation this range decreased. After methylation, the number average molecular weight of the Suwannee River fulvic acid remained the same while the weight average molecular weight decreased. These differences are probably indicative of disaggregation of large aggregated ions during methylation. Since the weight average molecular weight decreased, it is likely that aggregate formation in the fulvic acid was present prior to derivatization, rather than multiple charging in the mass spectra.

Tannins and terpenoids as major precursors of Suwannee River fulvic acid

USGS Publications Warehouse

Leenheer, Jerry A.; Rostad, Colleen E.

2004-01-01

Suwannee River fulvic acid (SRFA) was fractionated into 7 fractions by normal-phase chromatography on silica gel followed by reverse-phase fractionation on XAD-8 resin that produced 18 subfractions. Selected major subfractions were characterized by 13C-nuclear magnetic resonance (NMR), infrared spectrometry, and elemental analyses. 13C-NMR spectra of the subfractions were more indicative of precursor structures than unfractionated SRFA, and gave spectral profiles that indicated SRFA mass was about equally split between tannin precursors and terpenoid precursors. Lignin precursors were minor components. Synthesis of 13C-NMR data with elemental data for subfractions derived from both tannin and terpenoid precursors revealed high ring contents and low numbers of carbon per rings which is indicative of fused ring structures that are extensively substituted with carboxyl and methyl groups. These results ruled out extended chain structures for SRFA. This information is useful for determining sources and properties of fulvic acid in drinking water supplies as tannins are more reactive with chlorine to produce undesirable disinfection by-products than are terpenoids.

Factors that affect molecular weight distribution of Suwannee river fulvic acid as determined by electrospray ionization/mass spectrometry

USGS Publications Warehouse

Rostad, C.E.; Leenheer, J.A.

2004-01-01

Effects of methylation, molar response, multiple charging, solvents, and positive and negative ionization on molecular weight distributions of aquatic fulvic acid were investigated by electrospray ionization/mass spectrometry. After preliminary analysis by positive and negative modes, samples and mixtures of standards were derivatized by methylation to minimize ionization sites and reanalyzed.Positive ionization was less effective and produced more complex spectra than negative ionization. Ionization in methanol/water produced greater response than in acetonitrile/water. Molar response varied widely for the selected free acid standards when analyzed individually and in a mixture, but after methylation this range decreased. After methylation, the number average molecular weight of the Suwannee River fulvic acid remained the same while the weight average molecular weight decreased. These differences are probably indicative of disaggregation of large aggregated ions during methylation. Since the weight average molecular weight decreased, it is likely that aggregate formation in the fulvic acid was present prior to derivatization, rather than multiple charging in the mass spectra. ?? 2004 Elsevier B.V. All rights reserved.

Stability studies for titanium dioxide nanoparticles upon adsorption of Suwannee River humic and fulvic acids and natural organic matter.

PubMed

Erhayem, Mohamed; Sohn, Mary

2014-01-15

In many studies humic acid, fulvic acid, or natural organic matter is used interchangeably to model the effect of naturally derived organic matter on geochemical processes in the environment. In this study, the term NOOM (naturally occurring organic matter) is used to include both humic and fulvic acids as well as natural organic matter and compares the effect of NOOM type on NOOM removal onto nano-TiO2. In general, regardless of variations in solution chemistry, the order of the percentage of removal of NOOM onto nano-TiO2 was humic acid>natural organic matter>fulvic acid. The order of adsorption constant values of NOOM onto nano-TiO2 was also found to be humic acid>natural organic matter>fulvic acid under all conditions studied. The extent of NOOM removal by nano-TiO2 was enhanced in the presence of the divalent ions, magnesium and calcium, at pH7.8 when compared to the presence of the monovalent ions, sodium and potassium. Also, lower NOOM removal by nano-TiO2 in the presence of sodium salts of dihydrogen phosphate, bicarbonate and nitrate relative to chloride was observed and was likely due to the competition between polyatomic anions and NOOM adsorption onto the surface of nano-TiO2 indicating an anionic effect. Low concentrations of NOOM (10-20 mg L(-1)) destabilized nano-TiO2 in solution, however, the stability of nano-TiO2 increased as the amount of NOOM adsorbed onto nano-TiO2 increased at higher dissolved NOOM concentrations and significant stabilization was seen at 25 mg L(-1) NOOM. Thus, the three fractions of NOOM, humic and fulvic acids and natural organic matter and their concentrations were found to affect nano-TiO2 stability to different degrees although pH dependent trends in cation and anion effects had similar patterns. While the effects of adsorption of these three commonly used types of NOOM onto nanoparticles are similar, there are important differences that can be related to structural differences. © 2013.

Hydroxyl Radical Formation from HULIS and Fe(II) Interactions: Fulvic Acid-Fe(II) Complexes in Simulated and Human Lung Fluids

NASA Astrophysics Data System (ADS)

Gonzalez, D.

2017-12-01

Inhalation of fine particulate matter (PM2.5) has long been associated with adverse health outcomes. However, the causative agents and underlying mechanisms for these health effects have yet to be identified. One hypothesis is that PM2.5 deposited in the alveoli produce an excess of highly reactive radicals, leading to oxidative stress. The OH radical may be the most physiologically damaging, capable of oxidizing of lipids, proteins and DNA. Due to the variability and uncertainty in PM2.5 composition, the components that contribute to OH formation are not well understood. Soluble Fe is a component of PM2.5that produces OH under physiological conditions. Humic-like substances are water soluble organics found in biomass burning and tobacco smoke. Humic-like substances are capable of binding to Fe and enhancing OH formation, but this chemistry is not well understood. In this work, we use soil derived fulvic acid as a surrogate for Humic-like substances and investigate its effect on OH formation from Fe(II) under conditions relevant to the lungs. We use a fluorescent OH trapping probe, chemical kinetics and thermodynamic modeling to investigate OH formation from fulvic acid and Fe(II) dissolved in simulated and human lung fluids. In simulated lung fluid, we find that fulvic acid binds to Fe(II) and enhances the rate of key reactions that form OH. When fulvic acid is added to human lung fluids containing Fe(II), an enhancement of OH formation is observed. In human lung fluid, fulvic acid and metal binding proteins compete for Fe binding. These metal binding proteins are typically not found in simulated lung fluids. Results show that fulvic acid strongly binds Fe(II) and catalyzes key reactions that form OH in both simulated and human lung fluids. These results may help explain the role of Humic-like substances and Fe in oxidative stress and adverse health outcomes. Furthermore, we suggest that future studies employ simulated lung fluids containing metal binding proteins

Sorption of Th (IV) to silica as a function of pH, humic/fulvic acid, ionic strength, electrolyte type.

PubMed

Chen, Changlun; Wang, Xiangke

2007-02-01

The removal behavior of thorium (Th(IV)) has been investigated in multicomponent systems containing silica (SiO2) as the model of inorganic particles because of its widespread presence in the earth's crust and soil humic acid (HA)/fulvic acid (FA) by batch experiments. The influence of pH from 2 to 12, ionic strength from 0.02 to 0.2 M KNO3, soil HA/FA concentration from 8.3 to 22.5 mg/L, and foreign cations (Li+, Na+, K+) and anions (NO3(-), Cl-) on the sorption of Th(IV) onto SiO2 was also tested. The sorption isotherms of Th(IV) at approximately constant pH (3.50+/-0.02) were determined and analyzed regressively with three kinds of sorption isotherm models, i.e., linear, Langmuir, and Freundlich models. The results demonstrated that the sorption of Th(IV) onto SiO2 increased steeply with increasing pH from 2 to 4. Generally, humic substances (HSs) were shown to enhance Th(IV) sorption at low pH, but to reduce Th(IV) sorption at intermediate and high pH. It was a hypothesis that the significantly positive influence of HA/FA at pH from 2 to 4 on the sorption of Th(IV) onto SiO2 was attributed to strong surface binding of HA/FA on SiO2 and subsequently the formation of ternary surface complexes such as [triple bond]MO-O-HA-Th or [triple bond]MO-O-FA-Th. The results also demonstrated that the sorption was strongly dependent on the concentration of HA/FA, and independent of ionic strength and foreign ions under our experimental conditions.

Spectral characterization of the fluorescent components present in humic substances, fulvic acid and humic acid mixed with pure benzo(a)pyrene solution

NASA Astrophysics Data System (ADS)

El Fallah, Rawa; Rouillon, Régis; Vouvé, Florence

2018-06-01

The fate of benzo(a)pyrene (BaP), a ubiquitous contaminant reported to be persistent in the environment, is largely controlled by its interactions with the soil organic matter. In the present study, the spectral characteristics of fluorophores present in the physical fractions of the soil organic matter were investigated in the presence of pure BaP solution. After extraction of humic substances (HSs), and their fractionation into fluvic acid (FA) and humic acid (HA), two fluorescent compounds (C1 and C2) were identified and characterized in each physical soil fraction, by means of fluorescence excitation-emission matrices (FEEMs) and Parallel Factor Analysis (PARAFAC). Then, to each type of fraction having similar DOC content, was added an increasing volume of pure BaP solution in attempt to assess the behavior of BaP with the fluorophores present in each one. The application of FEEMs-PARAFAC method validated a three-component model that consisted of the two resulted fluorophores from HSs, FA and HA (C1 and C2) and a BaP-like fluorophore (C3). Spectral modifications were noted for components C2HSs (C2 in humic substances fraction) (λex/λem: 420/490-520 nm), C2FA (C2 in fulvic acid fraction) (λex/λem: 400/487(517) nm) and C1HA (C1 in humic acid fraction) (λex/λem: 350/452(520) nm). We explored the impact of increasing the volume of the added pure BaP solution on the scores of the fluorophores present in the soil fractions. It was found that the scores of C2HSs, C2FA, and C1HA increased when the volume of the added pure BaP solution increased. Superposition of the excitation spectra of these fluorophores with the emission spectrum of BaP showed significant overlaps that might explain the observed interactions between BaP and the fluorescent compounds present in SOM physical fractions.

Spectral characterization of the fluorescent components present in humic substances, fulvic acid and humic acid mixed with pure benzo(a)pyrene solution.

PubMed

El Fallah, Rawa; Rouillon, Régis; Vouvé, Florence

2018-06-15

The fate of benzo(a)pyrene (BaP), a ubiquitous contaminant reported to be persistent in the environment, is largely controlled by its interactions with the soil organic matter. In the present study, the spectral characteristics of fluorophores present in the physical fractions of the soil organic matter were investigated in the presence of pure BaP solution. After extraction of humic substances (HSs), and their fractionation into fluvic acid (FA) and humic acid (HA), two fluorescent compounds (C 1 and C 2 ) were identified and characterized in each physical soil fraction, by means of fluorescence excitation-emission matrices (FEEMs) and Parallel Factor Analysis (PARAFAC). Then, to each type of fraction having similar DOC content, was added an increasing volume of pure BaP solution in attempt to assess the behavior of BaP with the fluorophores present in each one. The application of FEEMs-PARAFAC method validated a three-component model that consisted of the two resulted fluorophores from HSs, FA and HA (C 1 and C 2 ) and a BaP-like fluorophore (C 3 ). Spectral modifications were noted for components C 2 HSs (C 2 in humic substances fraction) (λex/λem: 420/490-520 nm), C 2 FA (C 2 in fulvic acid fraction) (λex/λem: 400/487(517) nm) and C 1 HA (C 1 in humic acid fraction) (λex/λem: 350/452(520) nm). We explored the impact of increasing the volume of the added pure BaP solution on the scores of the fluorophores present in the soil fractions. It was found that the scores of C 2 HSs, C 2 FA, and C 1 HA increased when the volume of the added pure BaP solution increased. Superposition of the excitation spectra of these fluorophores with the emission spectrum of BaP showed significant overlaps that might explain the observed interactions between BaP and the fluorescent compounds present in SOM physical fractions. Copyright © 2018 Elsevier B.V. All rights reserved.

Comparative investigation of low-molecular-weight fulvic acids of different origin by SEC-Q-TOF-ms: new insights into structure and formation.

PubMed

Reemtsma, Thorsten; These, Anja

2005-05-15

Size exclusion chromatography (SEC) coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) was used to analyze the elemental composition and structure of low-molecular-weight fulvic acid molecules. It is shown that the set of hundreds of individual molecules form a homogeneous and structurally unique class of compounds that can be clearly differentiated from any other class of biogenic matter investigated to date. The molecular composition of low-molecular-weight fulvic acids in isolates of very different origin (surface water, groundwater, peat) is virtually indistinguishable. Significant and characteristic differences are, however, recognized when qualitative information and quantitative information provided by ESI-Q-TOF-MS are linked to each other. The relative frequency of the various molecules in each mixture can differ significantly, with the peat showing higher intensity of the aromatic and less carboxylated molecules of this set, whereas the aquatic fulvic acids show a strong contribution of the molecules with less aromaticity and a higher carboxylate content. The identity of fulvic acid molecules in isolates of different origin implies that no specific source material is required forfulvic acid formation but that they may be formed from different sources by different oxidative processes.

Effects of growth stage and fulvic acid on the diversity and dynamics of endophytic bacterial community in Stevia rebaudiana Bertoni leaves

PubMed Central

Yu, Xuejian; Yang, Jinshui; Wang, Entao; Li, Baozhen; Yuan, Hongli

2015-01-01

The aim of this study was to learn the interactions among the endophytic bacteria, the plant growth, the foliar spray of fulvic acid, and the accumulation of steviol glycosides in the leaves of Stevia rebaudiana. Metagenomic DNA was extracted from the Stevia leaves at different growth stages with or without the fulvic acid treatment; and the diversity of endophytic bacteria in Stevia leaves was estimated by pyrosequencing of 16S rRNA genes. As results, Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes were found to be the dominant phyla despite the growth stages and fulvic acid application. Stevia growth stages strongly regulated composition of endophytic community. The genera Agrobacterium (12.3%) and Erwinia (7.2%) dominated in seedling stage were apparently declined in the vegetable and initial flowering stages, while Sphingomonas and Methylobacterium increased in mature leaves at harvest time, which showed that the mature leaves of Stevia preferred to accumulate some certain endophytic bacteria. Sphingomonas and Methylobacterium constituted an important part of the core endophytic community and were positively correlated with the stevioside content and UGT74G1 gene expression, respectively; while Erwinia, Agrobacterium, and Bacillus were negatively correlated with the stevioside accumulation. Fulvic acid treatment accelerated the variation of endophytes along the growth stages and increased the steviol glycosides content. This is the first study to reveal the community composition of endophytic bacteria in the Stevia leaves, to evidence the strong effects of growth stage and fulvic acid application on the endophytes of Stevia, and to demonstrate the correlation between the endophytic bacteria and the steviol glycosides accumulation. PMID:26379644

Influence of pH, soil humic/fulvic acid, ionic strength, foreign ions and addition sequences on adsorption of Pb(II) onto GMZ bentonite.

PubMed

Wang, Suowei; Hu, Jun; Li, Jiaxing; Dong, Yunhui

2009-08-15

This work contributed to the adsorption of Pb(II) onto GMZ bentonite in the absence and presence of soil humic acid (HA)/fulvic acid (FA) using a batch technique. The influences of pH from 2 to 12, ionic strengths from 0.004M to 0.05M NaNO(3), soil HA/FA concentrations from 1.6 mg/L to 20mg/L, foreign cations (Li+, Na+, K+), anions (Cl(-), NO(3)(-)), and addition sequences on the adsorption of Pb(II) onto GMZ bentonite were tested. The adsorption isotherms of Pb(II) were determined at pH 3.6+/-0.1 and simulated with the Langmuir, Freundlich, and D-R adsorption models, respectively. The results demonstrated that the adsorption of Pb(II) onto GMZ bentonite increased with increasing pH from 2 to 6. HA was shown to enhance Pb(II) adsorption at low pH, but to reduce Pb(II) adsorption at high pH, whereas FA was shown to decrease Pb(II) adsorption at pH from 2 to 11. The results also demonstrated that the adsorption was strongly dependent on ionic strength and slightly dependent on the concentration of HA/FA. The adsorption of Pb(II) onto GMZ bentonite was dependent on foreign ions in solution. The addition sequences of bentonite/Pb(II)/HA had no effect on the adsorption of Pb(II).

Characterization of fulvic acid fractions of dissolved organic matter during ice-out in a hyper-eutrophic, coastal pond in Antarctica

NASA Astrophysics Data System (ADS)

Cawley, Kaelin M.; McKnight, Diane M.; Miller, Penney; Cory, Rose; Fimmen, Ryan L.; Guerard, Jennifer; Dieser, Markus; Jaros, Christopher; Chin, Yu-Ping; Foreman, Christine

2013-12-01

Dissolved humic material (HDOM) is ubiquitous to all natural waters and its source material influences its chemical structure, reactivity, and bioavailability. While terrestrially derived HDOM reference materials distributed by the International Humic Substances Society (IHSS) have been readily available to engineering and scientific communities, a microbially derived reference HDOM was not, despite the well-characterized differences in the chemistry and reactivity of HDOM derived from terrestrial versus microbial sources. To address this gap, we collected a microbial reference fulvic acid from Pony Lake (PLFA) for distribution through the IHSS. Pony Lake is a saline coastal pond on Ross Island, Antarctica, where the landscape is devoid of terrestrial plants. Sample collection occurred over a 17-day period in the summer season at Pony Lake. During this time, the dissolved organic carbon (DOC) concentrations increased nearly two-fold, and the fulvic acid fraction (collected using the XAD-8 method) accounted for 14.6% of the DOC. During the re-concentration and desalting procedures we isolated two other chemically distinct fulvic acid fractions: (1) PLFA-2, which was high in carbohydrates and (2) PLFA-CER, which was high in nitrogen. The chemical characteristics (elemental analysis, optical characterization with UV-vis and fluorescence spectroscopy, and 13C NMR spectroscopy) of the three fulvic acid fractions helped to explain their behavior during isolation.

Characterization of Nanoparticles and Colloids in Aquatic Systems 1. Small Angle Neutron Scattering Investigations of Suwannee River Fulvic Acid Aggregates in Aqueous Solutions

NASA Astrophysics Data System (ADS)

Diallo, Mamadou S.; Glinka, Charles J.; Goddard, William A.; Johnson, James H.

2005-10-01

Fulvic acids (FA) and humic acids (HA) constitute 30-50% of dissolved organic matter in natural aquatic systems. In aqueous solutions, a commonly accepted view is that FA and HA exist as soluble macroligands at low concentration and as supramolecular aggregates at higher concentration. The size, shape and structure of these aggregates are still the subject of ongoing debate in the environmental chemistry literature. In this article, we use small angle neutron scattering (SANS) to assess the effects of solute concentration, solution pH and background electrolyte (NaCl) concentration on the structures of Suwannee River FA (SRFA) aggregates in D2O. The qualitative features of the SANS curves and data analysis are not consistent with the view point that SRFA forms micelle-like aggregates as its concentration in aqueous solution increases. We find that SRFA forms fractal aggregates in D20 with size greater than 242 nm. The SRFA aggregates undergo a significant degree of restructuring in compactness as solution pH, solute concentration and NaCl concentration increase.

Sensitized photooxidation of phenols by fulvic acid and in natural waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faust, B.C.; Hoigne, J.

1987-10-01

In addition to singlet oxygen, irradiation of fulvic acid solutions and lake water with UV and visible light (lambda > 315 nm) produces another transient oxidant species. This transient oxidant (probably an organic peroxy radical) is derived from natural dissolved organic material (DOM) and controls DOM-sensitized photooxidations of various alkylphenols. On the basis of kinetic data for the transient oxidant, DOM-sensitized photooxidation half-lives of alkylphenols are estimated to range from 1 day to several months in middle-latitude shallow surface waters.

Characterization of the International Humic Substances Society standard and reference fulvic and humic acids by solution state carbon-13 (13C) and hydrogen-1 (1H) nuclear magnetic resonance spectrometry

USGS Publications Warehouse

Thorn, Kevin A.; Folan, Daniel W.; MacCarthy, Patrick

1989-01-01

Standard and reference samples of the International Humic Substances Society have been characterized by solution state carbon-13 and hydrogen-1 nuclear magnetic resonance (NMR) spectrometry. Samples included the Suwannee River, soil, and peat standard fulvic and humic acids, the Leonardite standard humic acid, the Nordic aquatic reference fulvic and humic acids, and the Summit Hill soil reference humic acid. Aqueous-solution carbon-13 NMR analyses included the measurement of spin-lattice relaxation times, measurement of nuclear Overhauser enhancement factors, measurement of quantitative carbon distributions, recording of attached proton test spectra, and recording of spectra under nonquantitative conditions. Distortionless enhancement by polarization transfer carbon-13 NMR spectra also were recorded on the Suwannee River fulvic acid in deuterated dimethyl sulfoxide. Hydrogen-1 NMR spectra were recorded on sodium salts of the samples in deuterium oxide. The carbon aromaticities of the samples ranged from 0.24 for the Suwannee River fulvic acid to 0.58 for the Leonardite humic acid.

Evaluation of a proposed standardized analytical method for the determination of humic and fulvic acids in commercial products

USDA-ARS?s Scientific Manuscript database

A constraint to growth of the commercial humic products industry has been the lack of a widely accepted procedure for determining humic acid and fulvic acid concentrations of the products, which has raised regulatory issues. On behalf of the U.S.-based Humic Products Trade Association, we developed ...

Characterization of interaction between amino acids and fulvic-like organic matter by fluorescence spectroscopy combining thermodynamic calculation.

PubMed

Lin, Tao; Hou, Bingwei; Wang, Jian; Xu, Yaqun; Chen, Wei

2017-03-01

Dissolved organic matter (DOM), as a very fine colloidal suspension, could inevitably affect the transformation process of dissolved organic nitrogen (DON) in drinking water treatment. Tryptophan and tyrosine were used as representatives of DON to investigate the interactions between amino acids and fulvic-like components of fluorescent DOM using titration experiments. The fluorescence intensity decreased significantly with the increasing fulvic acid (FA) concentration, suggesting that FA could greatly quench the intrinsic fluorescence of amino acids such as tryptophan and tyrosine. The absolute spectrum peaks of amino acids (AA) were changed in the presence of FA, possibly being resulted from non-covalent interactions between amino acids and FA. The specific hydrogen bonding and van der Waals forces played dominant roles in the interactions according to the results of theoretical analysis and thermodynamic calculation. The distance between donor and acceptor was 1.25 and 1.14 nm for the FA-tyrosine and FA-tryptophan system, indicating the energy transfer from tyrosine or tryptophan to FA. The association constant (K) decreased with the increase of temperature and pH value, while the change of ionic strength had no obvious influence on K value.

Trihalomethane formation potential of aquatic and terrestrial fulvic and humic acids: Sorption on activated carbon.

PubMed

Abouleish, Mohamed Y Z; Wells, Martha J M

2015-07-15

Humic substances (HSs) are precursors for the formation of hazardous disinfection by-products (DBPs) during chlorination of water. Various surrogate parameters have been used to investigate the generation of DBPs by HS precursors and the removal of these precursors by activated carbon treatment. Dissolved organic carbon (DOC)- and ultraviolet absorbance (UVA254)-based isotherms are commonly reported and presumed to be good predictors of the trihalomethane formation potential (THMFP). However, THMFP-based isotherms are rarely published such that the three types of parameters have not been compared directly. Batch equilibrium experiments on activated carbon were used to generate constant-initial-concentration sorption isotherms for well-characterized samples obtained from the International Humic Substances Society (IHSS). HSs representing type (fulvic acid [FA], humic acid [HA]), origin (aquatic, terrestrial), and geographical source (Nordic, Suwannee, Peat, Soil) were examined at pH6 and pH9. THMFP-based isotherms were generated and compared to determine if DOC- and UVA254-based isotherms were good predictors of the THMFP. The sorption process depended on the composition of the HSs and the chemical nature of the activated carbon, both of which were influenced by pH. Activated carbon removal of THM-precursors was pH- and HS-dependent. In some instances, the THMFP existed after UVA254 was depleted. Copyright © 2015 Elsevier B.V. All rights reserved.

Fulvic acid like organic compounds control nucleation of marine calcite under suboxic conditions

NASA Astrophysics Data System (ADS)

Neuweiler, Fritz; D'Orazio, Valeria; Immenhauser, Adrian; Geipel, Gerhard; Heise, Karl-Heinz; Cocozza, Claudio; Miano, Teodoro M.

2003-08-01

Intracrystalline organic compounds, enclosed within in situ precipitated marine microcrystalline calcite (automicrite), might represent either an inclusion or the catalyst of such precipitation. We use evidence from a Lower Cretaceous deep-water carbonate mound to show (1) the original source, (2) the degree of condensation, (3) the redox conditions involved, and (4) the catalytic role of natural organic matter for the precipitation of automicrite. Fluorescence spectrometry of the intracrystalline organic fraction extracted from these carbonates identifies a marine fulvic acid like organic compound with a low degree of polycondensation. This finding points to a temporal correlation of the initial stage of geopolymer formation with the precipitation of automicrite. Furthermore, the rare earth element (REE) distribution patterns in the mineral show a consistent positive Ce anomaly, suggesting an episode of reductive dissolution of iron-manganese oxyhydroxides during automicrite formation. In general, a relative enrichment of middle-weight REEs is observed, resulting in a convex distribution pattern typical for, e.g., phosphate concretions or humic acid material. By merging the results of spectrometry and REE geochemistry we thus conclude that the marine calcite precipitation was catalyzed by marine fulvic acid like compounds during the early stages of humification under suboxic conditions. This indicates that humification, driven by the presence of a benthic biomass, is more important for calcite authigenesis than any site-specific microbial metabolism. The Neoproterozoic rise of carbonate mounds supports this hypothesis; there is molecular evidence for early metazoan divergence then, but not for a major evolutionary episode of microorganisms.

Charge characteristics of humic and fulvic acids: comparative analysis by colloid titration and potentiometric titration with continuous pK-distribution function model.

PubMed

Bratskaya, S; Golikov, A; Lutsenko, T; Nesterova, O; Dudarchik, V

2008-09-01

Charge characteristics of humic and fulvic acids of a different origin (inshore soils, peat, marine sediments, and soil (lysimetric) waters) were evaluated by means of two alternative methods - colloid titration and potentiometric titration. In order to elucidate possible limitations of the colloid titration as an express method of analysis of low content of humic substances we monitored changes in acid-base properties and charge densities of humic substances with soil depth, fractionation, and origin. We have shown that both factors - strength of acidic groups and molecular weight distribution in humic and fulvic acids - can affect the reliability of colloid titration. Due to deviations from 1:1 stoichiometry in interactions of humic substances with polymeric cationic titrant, the colloid titration can underestimate total acidity (charge density) of humic substances with domination of weak acidic functional groups (pK>6) and high content of the fractions with molecular weight below 1kDa.

A new influence on iron dissolution in Bangladesh aquifers: electron shuttling by groundwater fulvic acids

NASA Astrophysics Data System (ADS)

Mladenov, N.; Kulkarni, H. V.; McKnight, D. M.; Zheng, Y.; Kirk, M. F.

2016-12-01

It was demonstrated more than two decades ago that the electron shuttling ability of fulvic acids (FA) accelerates iron (Fe) reduction. However, the environmental relevance of this mechanism for arsenic-laden groundwater environments has thus far only been hypothesized. Here we show that FAs isolated from high and low arsenic groundwater aquifers in the Bengal Basin can act to shuttle electrons between bacteria and Fe(III). Bangladesh groundwater FAs were reduced by Geobacter metallireducens and were subsequently capable of abiotically reducing Fe(III) to Fe(II). Moreover, all four Bangladesh groundwater FAs investigated in the study had higher Fe(III) to Fe(II) conversion rates compared to anthraquinone disulfonate, an oxidized quinone, and Suwannee River Fulvic Acid, a commercially-available FA isolated from a terrestrially-dominated surface water source. Until now, microbially-mediated reductive dissolution of Fe (oxy)hydroxides, driven by the availability of labile organic matter, was widely accepted as the main control on arsenic mobilization in reducing aquifers. Our evidence for the electron shuttling ability of Bangladesh FAs implicates electron shuttling as another important control on elevated As concentrations in groundwater of the Bengal Basin.

Calcite growth-rate inhibition by fulvic acid and magnesium ion—Possible influence on biogenic calcite formation

NASA Astrophysics Data System (ADS)

Reddy, Michael M.

2012-08-01

Increases in ocean surface water dissolved carbon dioxide (CO2) concentrations retard biocalcification by reducing calcite supersaturation (Ωc). Reduced calcification rates may influence growth-rate dependent magnesium ion (Mg) incorporation into biogenic calcite modifying the use of calcifying organisms as paleoclimate proxies. Fulvic acid (FA) at biocalcification sites may further reduce calcification rates. Calcite growth-rate inhibition by FA and Mg, two common constituents of seawater and soil water involved in the formation of biogenic calcite, was measured separately and in combination under identical, highly reproducible experimental conditions. Calcite growth rates (pH=8.5 and Ωc=4.5) are reduced by FA (0.5 mg/L) to 47% and by Mg (10-4 M) to 38%, compared to control experiments containing no added growth-rate inhibitor. Humic acid (HA) is twice as effective a calcite growth-rate inhibitor as FA. Calcite growth rate in the presence of both FA (0.5 mg/L) and Mg (10-4 M) is reduced to 5% of the control rate. Mg inhibits calcite growth rates by substitution for calcium ion at the growth site. In contrast, FA inhibits calcite growth rates by binding multiple carboxylate groups on the calcite surface. FA and Mg together have an increased affinity for the calcite growth sites reducing calcite growth rates.

Calcite growth-rate inhibition by fulvic acid and magnesium ion—Possible influence on biogenic calcite formation

USGS Publications Warehouse

Reddy, Michael M.

2012-01-01

Increases in ocean surface water dissolved carbon dioxide (CO2) concentrations retard biocalcification by reducing calcite supersaturation (Ωc). Reduced calcification rates may influence growth-rate dependent magnesium ion (Mg) incorporation into biogenic calcite modifying the use of calcifying organisms as paleoclimate proxies. Fulvic acid (FA) at biocalcification sites may further reduce calcification rates. Calcite growth-rate inhibition by FA and Mg, two common constituents of seawater and soil water involved in the formation of biogenic calcite, was measured separately and in combination under identical, highly reproducible experimental conditions. Calcite growth rates (pH=8.5 and Ωc=4.5) are reduced by FA (0.5 mg/L) to 47% and by Mg (10−4 M) to 38%, compared to control experiments containing no added growth-rate inhibitor. Humic acid (HA) is twice as effective a calcite growth-rate inhibitor as FA. Calcite growth rate in the presence of both FA (0.5 mg/L) and Mg (10−4 M) is reduced to 5% of the control rate. Mg inhibits calcite growth rates by substitution for calcium ion at the growth site. In contrast, FA inhibits calcite growth rates by binding multiple carboxylate groups on the calcite surface. FA and Mg together have an increased affinity for the calcite growth sites reducing calcite growth rates.

Interactions between stepwise-eluted sub-fractions of fulvic acids and protons revealed by fluorescence titration combined with EEM-PARAFAC.

PubMed

Song, Fanhao; Wu, Fengchang; Guo, Fei; Wang, Hao; Feng, Weiying; Zhou, Min; Deng, Yanghui; Bai, Yingchen; Xing, Baoshan; Giesy, John P

2017-12-15

In aquatic environments, pH can control environmental behaviors of fulvic acid (FA) via regulating hydrolysis of functional groups. Sub-fractions of FA, eluted using pyrophosphate buffers with initial pHs of 3.0 (FA 3 ), 5.0 (FA 5 ), 7.0 (FA 7 ), 9.0 (FA 9 ) and 13.0 (FA 13 ), were used to explore interactions between the various, operationally defined, FA fractions and protons, by use of EEM-PARAFAC analysis. Splitting of peaks (FA 3 and FA 13 ), merging of peaks (FA 7 ), disappearance of peaks (FA 9 and FA 13 ), and red/blue-shifting of peaks were observed during fluorescence titration. Fulvic-like components were identified from FA 3 -FA 13 , and protein-like components were observed in fractions FA 9 and FA 13 . There primary compounds (carboxylic-like, phenolic-like, and protein-like chromophores) in PARAFAC components were distinguished based on acid-base properties. Dissociation constants (pK a ) for fulvic-like components with proton ranged from 2.43 to 4.13 in an acidic pH and from 9.95 to 11.27 at basic pH. These results might be due to protonation of di-carboxylate and phenolic functional groups. At basic pH, pK a values of protein-like components (9.77-10.13) were similar to those of amino acids. However, at acidic pH, pK a values of protein-like components, which ranged from 3.33 to 4.22, were 1-2units greater than those of amino acids. Results presented here, will benefit understanding of environmental behaviors of FA, as well as interactions of FA with environmental contaminants. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Humic and Fulvic Acids on Silver Nanoparticle Stability, Dissolution, and Toxicity

PubMed Central

Gunsolus, Ian L.; Mousavi, Maral P. S.; Hussein, Kadir; Bühlmann, Philippe; Haynes, Christy L.

2015-01-01

The colloidal stability of silver nanoparticles (AgNPs) in natural aquatic environments influences their transport and environmental persistence, while their dissolution to Ag+ influences their toxicity to organisms. Here, we characterize the colloidal stability, dissolution behavior, and toxicity of two industrially relevant classes of AgNPs (i.e., AgNPs stabilized by citrate or polyvinylpyrrolidone) after exposure to natural organic matter (NOM, i.e., Suwannee River Humic and Fulvic Acid Standards and Pony Lake Fulvic Acid Reference). We show that NOM interaction with the nanoparticle surface depends on (i) the NOM’s chemical composition, where sulfur- and nitrogen-rich NOM more significantly increases colloidal stability, and (ii) the affinity of the capping agent for the AgNP surface, where nanoparticles with loosely bound capping agents are more effectively stabilized by NOM. Adsorption of NOM is shown to have little effect on AgNP dissolution under most experimental conditions, the exception being when the NOM is rich in sulfur and nitrogen. Similarly, the toxicity of AgNPs to a bacterial model (Shewanella oneidensis MR-1) decreases most significantly in the presence of sulfur- and nitrogen-rich NOM. Our data suggest that the rate of AgNP aggregation and dissolution in aquatic environments containing NOM will depend on the chemical composition of the NOM, and that the toxicity of AgNPs to aquatic microorganisms is controlled primarily by the extent of nanoparticle dissolution. PMID:26047330

Humic and fulvic acids: sink or source in the availability of metals to the marine bivalves Macoma balthicaand Potamocorbula amurensis?

USGS Publications Warehouse

Decho, Alan; Luoma, Samuel N.

1994-01-01

Humic acids (HA) and fulvic acids (FA) are common forms of organic matter in marine sedirnents, and are routinely ingested by deposit- and suspension-feeding animals. These compounds may be a sink for metals, implying that once metals are bound to humic substances they are no longer available to food webs. A series of experiments was conducted to quantitatively examine this premise using 2 estuarine bivalves from San Francisco Bay, USA: the suspension feeder Potarnocorbula arnurensis and the facultative deposit feeder Macoma balthica. HA and FA, isolated from marine sediments, were bound as organic coatings to either hydrous ferric oxides (HFO) or silica particles. Cd and Cr(II1) were adsorbed to the organic coatings or directly to uncoated HFO and silica particles. Pulse-chase laboratory feeding expenments using '"'Cd and "Cr(III) were then conducted to determine absorption efficiencies of Cd and Cr for individual specimens using each of the partlcle types. The results demonstrated that: (1) absorption of Cr(I1I) from all types of non-living particles was consistently low (< 11%). Ingested Cd showed greater bioavailability than Cr(IIl), perhaps due to differences in metal chemistry. (2) Bivalves absorbed Cd bound to uncoated HFO or silica particles (i.e. with no HA or FA present). (3) The presence of organic coatings on part~cles reduced Cd bioavailabhty compared with uncoated particles. (4) Both geochemical and biological conditions affected the food chain transfer of Cd. The data suggest that in marine systems inorganic and organic-coated particles are predominantly a sink for Cr in sediments. In the transfer of Cd to consumer animals, inorganic particles and humic substances can act as a link (although not a highly efficient one) under oxidized conditions.

Cu(II) binding by a pH-fractionated fulvic acid

USGS Publications Warehouse

Brown, G.K.; Cabaniss, S.E.; MacCarthy, P.; Leenheer, J.A.

1999-01-01

The relationship between acidity, Cu(II) binding and sorption to XAD resin was examined using Suwannee River fulvic acid (SRFA). The work was based on the hypothesis that fractions of SRFA eluted from an XAD column at various pH's from 1.0 to 12.0 would show systematic variations in acidity and possibly aromaticity which in turn would lead to different Cu(II) binding properties. We measured equilibrium Cu(II) binding to these fractions using Cu2+ ion-selective electrode (ISE) potentiometry at pH 6.0. Several model ligands were also examined, including cyclopentane-1,2,3,4-tetracarboxylic acid (CP-TCA) and tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THF-TCA), the latter binding Cu(II) much more strongly as a consequence of the ether linkage. The SRFA Cu(II) binding properties agreed with previous work at high ionic strength, and binding was enhanced substantially at lower ionic strength, in agreement with Poisson-Boltzmann predictions for small spheres. Determining Cu binding constants (K(i)) by non-linear regression with total ligand concentrations (L(Ti)) taken from previous work, the fractions eluted at varying pH had K(i) similar to the unfractionated SRFA, with a maximum enhancement of 0.50 log units. We conclude that variable-pH elution from XAD does not isolate significantly strong (or weak) Cu(II)-binding components from the SRFA mixture. Copyright (C) 1999 Elsevier Science B.V.

Eu(III)-Fulvic Acid Complexation: Evidence of Fulvic Acid Concentration Dependent Interactions by Time-Resolved Luminescence Spectroscopy.

PubMed

Kouhail, Yasmine Z; Benedetti, Marc F; Reiller, Pascal E

2016-04-05

Europium speciation is investigated by time-resolved luminescence spectroscopy (TRLS) in the presence of Suwannee River fulvic acid (SRFA). From complexation isotherms built at different total Eu(III) concentrations, pH values, ionic strength, and SRFA concentrations, it appears that two luminescence behaviors of Eu(III) are occurring. The first part, at the lowest CSRFA values, is showing the typical luminescence evolution of Eu(III) complexed by humic substances--that is, the increase of the asymmetry ratio between the (5)D0 → (7)F2 and (5)D0 → (7)F1 transitions up to a plateau--, and the occurrence of a biexponential decay--the first decay being faster than free Eu(3+). At higher CSRFA, a second luminescence mode is detected as the asymmetry ratio is increasing again after the previous plateau, and could correspond to the formation of another type of complex, and/or it can reflect a different spatial organization of complexed europium within the SRFA structure. The luminescence decay keeps on evolving but link to hydration number is not straightforward due to quenching mechanisms. The Eu(III) chemical environment evolution with CSRFA is also ionic strength dependent. These observations suggest that in addition to short-range interactions--intraparticulate complexation--, there might be interactions at longer range--interparticulate repulsion--between particles that are complexing Eu(III) at high CSRFA. These interactions are not yet accounted by the different complexation models.

Humic and fulvic acids: sink or source in the availability of metals to the marine bivalves Macoma balthica and Potamocorbula amurensis?

USGS Publications Warehouse

Decho, Alan W.; Luoma, Samuel N.

1994-01-01

Humic acids (HA) and fulvic acids (FA) are common forms of organic matter in marine sediments, and are routinely ingested by deposit- and suspension-feeding animals. These compounds may be a sink for metals, implying that once metals are bound to humic substances they are no longer available to food webs. A series of experiments was conducted to quantitatively examine this premise using 2 estuarine bivalves from San Francisco Bay, USA: the suspension feeder Potarnocorbula arnurensis and the facultative deposit feeder Macoma balthica. HA and FA, isolated from marine sediments, were bound as organic coatings to either hydrous ferric oxides (HFO) or silica particles. Cd and Cr(II1) were adsorbed to the organic coatings or directly to uncoated HFO and silica particles. Pulse-chase laboratory feeding expenments using 109Cd and 51Cr(III) were then conducted to determine absorption efficiencies of Cd and Cr for individual specimens using each of the particle types. The results demonstrated that: (1) absorption of Cr(I1I) from all types of non-living particles was consistently low (< 11%). Ingested Cd showed greater bioavailability than Cr(IIl), perhaps due to differences in metal chemistry. (2) Bivalves absorbed Cd bound to uncoated HFO or silica particles (i.e. with no HA or FA present). (3) The presence of organic coatings on particles reduced Cd bioavailabhty compared with uncoated particles. (4) Both geochemical and biological conditions affected the food chain transfer of Cd. The data suggest that in marine systems inorganic and organic-coated particles are predominantly a sink for Cr in sediments. In the transfer of Cd to consumer animals, inorganic particles and humic substances can act as a link (although not a highly efficient one) under oxidized conditions.

Speciation of aqueous Ni(II)-carboxylate and Ni(II)-fulvic acid solutions: Combined ATR-FTIR and XAFS analysis

NASA Astrophysics Data System (ADS)

Strathmann, Timothy J.; Myneni, Satish C. B.

2004-09-01

Aqueous solutions containing Ni(II) and a series of structurally related carboxylic acids were analyzed using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and Ni K-edge X-ray absorption fine structure spectroscopy (XAFS). XAFS spectra were also collected for solutions containing Ni 2+ and chelating ligands (ethylenediaminetetraacetic acid, nitrilotriacetic acid (NTA)) as well as soil fulvic acid. Limited spectral changes are observed for aqueous Ni(II) complexes with monocarboxylates (formate, acetate) and long-chain polycarboxylates (succinate, tricarballylate), where individual donor groups are separated by multiple bridging methylene groups. These spectral changes indicate weak interactions between Ni(II) and carboxylates, and the trends are similar to some earlier reports for crystalline Ni(II)-acetate solids, for which X-ray crystallography studies have indicated monodentate Ni(II)-carboxylate coordination. Nonetheless, electrostatic or outer-sphere coordination cannot be ruled out for these complexes. However, spectral changes observed for short-chain dicarboxylates (oxalate, malonate) and carboxylates that contain an alcohol donor group adjacent to one of the carboxylate groups (lactate, malate, citrate) demonstrate inner-sphere metal coordination by multiple donor groups. XAFS spectral fits of Ni(II) solutions containing soil fulvic acid are consistent with inner-sphere Ni(II) coordination by one or more carboxylate groups, but spectra are noisy and outer-sphere modes of coordination cannot be ruled out. These molecular studies refine our understanding of the interactions between carboxylates and weakly complexing divalent transition metals, such as Ni(II).

Complexation of furosemide with fulvic acid extracted from shilajit: a novel approach.

PubMed

Agarwal, Suraj Prakash; Anwer, Mohammad Khalid; Aqil, Mohammad

2008-05-01

The aim of the present work was to complex furosemide (FSM) with fulvic acid (FA) extracted from shilajit with the hope of having a better understanding of the complexation behavior. The effect of FA on the aqueous solubility, dissolution rate, and permeability of FSM was investigated. Different techniques, such as grinding, freeze drying, solvent evaporation, and so forth, were used for the preparation of the complex. The complexes were prepared in molar ratios of 1:1 and 1:2 FSM:FA and were evaluated for drug inclusion, solubility, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, dissolution study, and permeation study. These methods confirm the formation of an amorphous inclusion complex of FSM with FA.

Calcite growth-rate inhibition by fulvic acids isolated from Big Soda Lake, Nevada, USA, The Suwannee River, Georgia, USA and by polycarboxylic acids

USGS Publications Warehouse

Reddy, Michael M.; Leenheer, Jerry

2011-01-01

Calcite crystallization rates are characterized using a constant solution composition at 25°C, pH=8.5, and calcite supersaturation (Ω) of 4.5 in the absence and presence of fulvic acids isolated from Big Soda Lake, Nevada (BSLFA), and a fulvic acid from the Suwannee River, Georgia (SRFA). Rates are also measured in the presence and absence of low-molar mass, aliphatic-alicyclic polycarboxylic acids (PCA). BSLFA inhibits calcite crystal-growth rates with increasing BSLFA concentration, suggesting that BSLFA adsorbs at growth sites on the calcite crystal surface. Calcite growth morphology in the presence of BSLFA differed from growth in its absence, supporting an adsorption mechanism of calcite-growth inhibition by BSLFA. Calcite growth-rate inhibition by BSLFA is consistent with a model indicating that polycarboxylic acid molecules present in BSLFA adsorb at growth sites on the calcite crystal surface. In contrast to published results for an unfractionated SRFA, there is dramatic calcite growth inhibition (at a concentration of 1 mg/L) by a SRFA fraction eluted by pH 5 solution from XAD-8 resin, indicating that calcite growth-rate inhibition is related to specific SRFA component fractions. A cyclic PCA, 1, 2, 3, 4, 5, 6-cyclohexane hexacarboxylic acid (CHXHCA) is a strong calcite growth-rate inhibitor at concentrations less than 0.1 mg/L. Two other cyclic PCAs, 1, 1 cyclopentanedicarboxylic acid (CPDCA) and 1, 1 cyclobutanedicarboxylic acid (CBDCA) with the carboxylic acid groups attached to the same ring carbon atom, have no effect on calcite growth rates up to concentrations of 10 mg/L. Organic matter ad-sorbed from the air onto the seed crystals has no effect on the measured calcite crystal-growth rates.

Mass spectrometric screening and identification of acidic metabolites in fulvic acid fractions of contaminated groundwater.

PubMed

Jobelius, Carsten; Frimmel, Fritz H; Zwiener, Christian

2014-05-01

The anaerobic microbial degradation of aromatic and heterocyclic compounds is a prevalent process in contaminated groundwater systems. The introduction of functional groups into the contaminant molecules often results in aromatic and heterocyclic and succinic acids. These metabolites can be used as indicators for prevailing degradation processes. Therefore, there is a strong interest in developing analytical methods for screening and identification of these metabolites. In this study, neutral loss scans (NLS) by liquid chromatography-electrospray ionization/tandem mass spectrometry with losses of CO2 (NL ∆m/z = 44) and C2H4(CO2)2 (NL ∆m/z = 116) were applied for the first time successfully to screen selectively for acidic and succinic metabolites of aromatic and heterocyclic contaminants in two fulvic acid fractions from a contaminated site and a downstream region of a tar oil-polluted groundwater. Identification of these preselected signals was performed by high-resolution mass spectrometry with a liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry instrument. High-resolution mass and mass fragmentation data were then compared with a list of known metabolites from a literature search or matched with chemical databases supported with in silico fragmentation. Based on authentic analytical standards, several compounds from NLS were identified (e.g., 4-hydroxy-3-methylbenzoic acid, benzylsuccinic acid, naphthyl-2-methylsuccinic acid, 2-carboxyindane, and 2-carboxybenzothiophene) and tentatively identified (e.g., benzofuranmethylsuccinic acid and dihydrocarboxybenzothiophene) as aromatic, phenolic, heterocyclic, and succinic acids. The acidic metabolites were found exclusively in the contaminated region of the aquifer which indicates active biodegradation processes and no relevant occurrence of acidic metabolites in the downstream region.

The use of variable temperature and magic-angle sample spinning in studies of fulvic acids

USGS Publications Warehouse

Earl, W.L.; Wershaw, R. L.; Thorn, K.A.

1987-01-01

Intensity distortions and poor signal to noise in the cross-polarization magic-angle sample spinning NMR of fulvic acids were investigated and attributed to molecular mobility in these ostensibly "solid" materials. We have shown that inefficiencies in cross polarization can be overcome by lowering the sample temperature to about -60??C. These difficulties can be generalized to many other synthetic and natural products. The use of variable temperature and cross-polarization intensity as a function of contact time can yield valuable qualitative information which can aid in the characterization of many materials. ?? 1987.

Seasonal variation and mixing behaviour of glutathione, thioacetamide and fulvic acids in a temperate macrotidal estuary (Aulne, NW France)

NASA Astrophysics Data System (ADS)

Marie, Lauriane; Pernet-Coudrier, Benoît; Waeles, Matthieu; Riso, Ricardo

2017-01-01

Fulvic acids and two dissolved reduced sulphur substances (RSS) were analysed for one year along the whole salinity gradient in the Aulne estuary (north-western France) using differential pulse cathodic stripping voltammetry. Concentrations of glutathione-like (GSH-like), thioacetamide-like (TA-like) and fulvic acid-like (FA-like) compounds ranged from 0.2 to 38 nmol L-1, from 0.02 to 6.6 μmol L-1 and from 0.1 to 4 mgC L-1, respectively. Our results indicated primarily allochthonous-continental sources for all three compounds. The behaviour of GSH-like compounds along the salinity gradient was globally conservative, with minor losses (<25%), possibly limited due to metal complexation. TA-like compounds generally displayed non-conservative behaviour with important removals. In terms of the TA-like budget, losses were counterbalanced by exceptional inputs occurring in the flood period (February). FA-like compounds were intensely degraded (∼50%) in the last section of the river and then behaved conservatively in the estuary. The annual flux of FA-like compounds to coastal waters was 2800 ± 600 tC. This flux was mainly (74%) delivered during the high discharge period, in accordance with its known pedogenic origin.

Copper binding to soil fulvic and humic acids: NICA-Donnan modeling and conditional affinity spectra.

PubMed

Xu, Jinling; Tan, Wenfeng; Xiong, Juan; Wang, Mingxia; Fang, Linchuan; Koopal, Luuk K

2016-07-01

Binding of Cu(II) to soil fulvic acid (JGFA), soil humic acids (JGHA, JLHA), and lignite-based humic acid (PAHA) was investigated through NICA-Donnan modeling and conditional affinity spectrum (CAS). It is to extend the knowledge of copper binding by soil humic substances (HS) both in respect of enlarging the database of metal ion binding to HS and obtaining a good insight into Cu binding to the functional groups of FA and HA by using the NICA-Donnan model to unravel the intrinsic and conditional affinity spectra. Results showed that Cu binding to HS increased with increasing pH and decreasing ionic strength. The amount of Cu bound to the HAs was larger than the amount bound to JGFA. Milne's generic parameters did not provide satisfactory predictions for the present soil HS samples, while material-specific NICA-Donnan model parameters described and predicted Cu binding to the HS well. Both the 'low' and 'high' concentration fitting procedures indicated a substantial bidentate structure of the Cu complexes with HS. By means of CAS underlying NICA isotherm, which was scarcely used, the nature of the binding at different solution conditions for a given sample and the differences in binding mode were illustrated. It was indicated that carboxylic group played an indispensable role in Cu binding to HS in that the carboxylic CAS had stronger conditional affinity than the phenolic distribution due to its large degree of proton dissociation. The fact was especially true for JGFA and JLHA which contain much larger amount of carboxylic groups, and the occupation of phenolic sites by Cu was negligible. Comparable amounts of carboxylic and phenolic groups on PAHA and JGHA, increased the occupation of phenolic type sites by Cu. The binding strength of PAHA-Cu and JGHA-Cu was stronger than that of JGFA-Cu and JLHA-Cu. The presence of phenolic groups increased the chance of forming more stable complexes, such as the salicylate-Cu or catechol-Cu type structures. Copyright © 2016

Examination of soil contaminated by coal-liquids by size exclusion chromatography in 1-methyl-2-pyrrolidinone solution to evaluate interference from humic and fulvic acids and extracts from peat.

PubMed

Morgan, T J; Herod, A A; Brain, S A; Chambers, F M; Kandiyoti, R

2005-11-18

Soil from a redundant coke oven site has been examined by extraction of soluble materials using 1-methyl-2-pyrrolidinone (NMP) followed by size exclusion chromatography (SEC) of the extracted material. The extracted material was found to closely resemble a high temperature coal tar pitch. Standard humic and fulvic acids were also examined since these materials are very soluble in NMP and would be extracted with pitch if present in the soil. Humic substances derived from peat samples and NMP-extracts of peats were also examined. The results show that the humic and fulvic substances were not extracted directly by NMP from peats. They were extracted using caustic soda solution and were different from the peat extracts in NMP. These results indicate that humic and fulvic acids were soluble in NMP in the protonated polyelectrolyte form but not in the original native polyelectrolyte form. The extraction of soil using NMP followed by SEC appears to be a promising method for identifying contamination by coal-based industries.

Effect of molecular weight of hyaluronic acid (HA) on viscoelasticity and particle texturing feel of HA dermal biphasic fillers.

PubMed

Chun, Cheolbyong; Lee, Deuk Yong; Kim, Jin-Tae; Kwon, Mi-Kyung; Kim, Young-Zu; Kim, Seok-Soon

2016-01-01

Hyaluronic acid (HA) dermal biphasic fillers are synthesized for their efficacy in correcting aesthetic defects such as wrinkles, scars and facial contouring defects. The fillers consist of crosslinked HA microspheres suspended in a noncrosslinked HA. To extend the duration of HAs within the dermis and obtain the particle texturing feel, HAs are crosslinked to obtain the suitable mechanical properties. Hyaluronic acid (HA) dermal biphasic fillers are prepared by mixing the crosslinked HA microspheres and the noncrosslinked HAs. The elastic modulus of the fillers increased with raising the volume fraction of the microspheres. The mechanical properties and the particle texturing feel of the fillers made from crosslinked HA (1058 kDa) microspheres suspended in noncrosslinked HA (1368 kDa) are successfully achieved, which are adequate for the fillers. Dermal biphasic HA fillers made from 1058 kDa exhibit suitable elastic moduli (211 to 420 Pa) and particle texturing feel (scale 7 ~ 9).

Complement-fixing Activity of Fulvic Acid from Shilajit and Other Natural Sources

PubMed Central

Schepetkin, Igor A.; Xie, Gang; Jutila, Mark A.; Quinn, Mark T.

2008-01-01

Shilajit has been used traditionally in folk medicine for treatment of a variety of disorders, including syndromes involving excessive complement activation. Extracts of Shilajit contain significant amounts of fulvic acid (FA), and it has been suggested that FA is responsible for many therapeutic properties of Shilajit. However, little is known regarding physical and chemical properties of Shilajit extracts, and nothing is known about their effects on the complement system. To address this issue, we fractionated extracts of commercial Shilajit using anion exchange and size-exclusion chromatography. One neutral (S-I) and two acidic (S-II and S-III) fractions were isolated, characterized, and compared with standardized FA samples. The most abundant fraction (S-II) was further fractionated into three sub-fractions (S-II-1 to S-II-3). The van Krevelen diagram showed that the Shilajit fractions are products of polysaccharide degradation, and all fractions, except S-II-3, contained type II arabinogalactan. All Shilajit fractions exhibited dose-dependent complement-fixing activity in vitro with high potency. Furthermore, we found a strong correlation between complement-fixing activity and carboxylic group content in the Shilajit fractions and other FA sources. These data provide a molecular basis to explain at least part of the beneficial therapeutic properties of Shilajit and other humic extracts. PMID:19107845

HA Antibody-Mediated FcγRIIIa Activity Is Both Dependent on FcR Engagement and Interactions between HA and Sialic Acids.

PubMed

Cox, Freek; Kwaks, Ted; Brandenburg, Boerries; Koldijk, Martin H; Klaren, Vincent; Smal, Bastiaan; Korse, Hans J W M; Geelen, Eric; Tettero, Lisanne; Zuijdgeest, David; Stoop, Esther J M; Saeland, Eirikur; Vogels, Ronald; Friesen, Robert H E; Koudstaal, Wouter; Goudsmit, Jaap

2016-01-01

Interactions with receptors for the Fc region of IgG (FcγRs) have been shown to contribute to the in vivo protection against influenza A viruses provided by broadly neutralizing antibodies (bnAbs) that bind to the viral hemagglutinin (HA) stem. In particular, Fc-mediated antibody-dependent cellular cytotoxicity (ADCC) has been shown to contribute to protection by stem-binding bnAbs. Fc-mediated effector functions appear not to contribute to protection provided by strain-specific HA head-binding antibodies. We used a panel of anti-stem and anti-head influenza A and B monoclonal antibodies with identical human IgG1 Fc domains and investigated their ability to mediate ADCC-associated FcγRIIIa activation. Antibodies which do not interfere with sialic acid binding of HA can mediate FcγRIIIa activation. However, the FcγRIIIa activation was inhibited when a mutant HA, unable to bind sialic acids, was used. Antibodies which block sialic acid receptor interactions of HA interfered with FcγRIIIa activation. The inhibition of FcγRIIIa activation by HA head-binding and sialic acid receptor-blocking antibodies was confirmed in plasma samples of H5N1 vaccinated human subjects. Together, these results suggest that in addition to Fc-FcγR binding, interactions between HA and sialic acids on immune cells are required for optimal Fc-mediated effector functions by anti-HA antibodies.

The lignin component of humic substances: Distribution among soil and sedimentary humic, fulvic, and base-insoluble fractions

NASA Astrophysics Data System (ADS)

Ertel, John R.; Hedges, John I.

1984-10-01

Vanillyl, syringyl and cinnamyl phenols occur as CuO oxidation products of humic, fulvic and base-insoluble residual fractions from soils, peat and nearshore marine sediments. However, none of these lignin-derived phenols were released by CuO oxidation of deepsea sediment or its base-extractable organic fractions. Lignin analysis indicated that peat and coastal marine sediments contained significantly higher levels of recognizable vascular plant carbon (20-50%) than soils and offshore marine sediments (0-10%). Although accounting for less than 20% of the total sedimentary (bulk) lignin, lignin components of humic acid fractions compositionally and quantitatively resembled the corresponding bulk samples and baseinsoluble residues. Recognizable lignin, presumably present as intact phenylpropanoid units, accounted for up to 5% of the carbon in peat and coastal humic acids but less than 1% in soil humic acids. Fulvic acid fractions uniformly yielded less lignin-derived phenols in mixtures that were depleted in syringyl and cinnamyl phenols relative to the corresponding humic acid fractions. Within the vanillyl and syringyl families the relative distribution of acidic and aldehydic phenols is a sensitive measure of the degree of oxidative alteration of the lignin component The high acid/aldehyde ratios and the low phenol yields of soils and their humic fractions compared to peat and coastal sediments indicate extensive degradation of the lignin source material. Likewise, the progressively higher acid/aldehyde ratios and lower phenol yields along the sequence: plant tissues (plant debris)-humic acids-fulvic acids suggest that this pattern represents the diagenetic sequence for the aerobic degradation of lignin biopolymers.

Complement-fixing activity of fulvic acid from Shilajit and other natural sources.

PubMed

Schepetkin, Igor A; Xie, Gang; Jutila, Mark A; Quinn, Mark T

2009-03-01

Shilajit has been used traditionally in folk medicine for the treatment of a variety of disorders, including syndromes involving excessive complement activation. Extracts of Shilajit contain significant amounts of fulvic acid (FA), and it has been suggested that FA is responsible for many therapeutic properties of Shilajit. However, little is known regarding the physical and chemical properties of Shilajit extracts, and nothing is known about their effects on the complement system. To address this issue, extracts of commercial Shilajit were fractionated using anion exchange and size-exclusion chromatography. One neutral (S-I) and two acidic (S-II and S-III) fractions were isolated, characterized and compared with standardized FA samples. The most abundant fraction (S-II) was further fractionated into three sub-fractions (S-II-1 to S-II-3). The van Krevelen diagram showed that the Shilajit fractions are the products of polysaccharide degradation, and all fractions, except S-II-3, contained type II arabinogalactan. All Shilajit fractions exhibited dose-dependent complement-fixing activity in vitro with high potency. Furthermore, a strong correlation was found between the complement-fixing activity and carboxylic group content in the Shilajit fractions and other FA sources. These data provide a molecular basis to explain at least part of the beneficial therapeutic properties of Shilajit and other humic extracts. (c) 2008 John Wiley & Sons, Ltd.

Simultaneous determination of Ca, Cu, Ni, Zn and Cd binding strengths with fulvic acid fractions by Schubert's method

USGS Publications Warehouse

Brown, G.K.; MacCarthy, P.; Leenheer, J.A.

1999-01-01

The equilibrium binding of Ca2+, Ni2+, Cd2+, Cu2+ and Zn2+ with unfractionated Suwannee river fulvic acid (SRFA) and an enhanced metal binding subfraction of SRFA was measured using Schubert's ion-exchange method at pH 6.0 and at an ionic strength (??) of 0.1 (NaNO3). The fractionation and subfractionation were directed towards obtaining an isolate with an elevated metal binding capacity or binding strength as estimated by Cu2+ potentiometry (ISE). Fractions were obtained by stepwise eluting an XAD-8 column loaded with SRFA with water eluents of pH 1.0 to pH 12.0. Subfractions were obtained by loading the fraction eluted from XAD-8 at pH 5.0 onto a silica gel column and eluting with solvents of increasing polarity. Schuberts ion exchange method was rigorously tested by measuring simultaneously the conditional stability constants (K) of citric acid complexed with the five metals at pH 3.5 and 6.0. The logK of SRFA with Ca2+, Ni2+, Cd2+, Cu2+ and Zn2+ determined simultaneously at pH 6.0 follow the sequence of Cu2+>Cd2+>Ni2+>Zn2+>Ca2+ while all logK values increased for the enhanced metal binding subfraction and followed a different sequence of Cu2+>Cd2+>Ca2+>Ni2+>Zn2+. Both fulvic acid samples and citric acid exhibited a 1:1 metal to ligand stochiometry under the relatively low metal loading conditions used here. Quantitative 13C nuclear magnetic resonance spectroscopy showed increases in aromaticity and ketone content and decreases in aliphatic carbon for the elevated metal binding fraction while the carboxyl carbon, and elemental nitrogen, phosphorus, and sulfur content did not change. The more polar, elevated metal binding fraction did show a significant increase in molecular weight over the unfractionated SRFA. Copyright (C) 1999 Elsevier Science B.V.

Effects of a dietary complex of humic and fulvic acids (FeedMAX 15) on the health and production of feedlot cattle destined for the Australian domestic market.

PubMed

Cusack, P M V

2008-01-01

To examine the effects of a dietary humic and fulvic acid complex, FeedMAX 15, on the health, growth rate, feed conversion ratio, and carcase characteristics of feedlot cattle. Cattle, in eight pens of 125 animals each, were fed either a diet containing a humic and fulvic acid complex (FeedMAX 15, FeedMAX Industries, Toowoomba, Queensland) or the same diet without the additive. Control or FeedMAX 15 diets were allocated to each pen at random. Individual cattle were allocated alternately to control or treatment pens based on order of presentation. Comparisons of disease incidence, mortality, feed intake, growth rate, feed conversion ratio, fat depth, dressing percentage, meat colour, fat colour and marbling were made at the conclusion of the feeding period. No differences were found between cattle fed FeedMAX 15 and cattle not fed the additive in entry body weight (P = 0.99), exit body weight (P = 0.91), dressing percentage (P = 0.66), P8 fat depth (P = 0.57), meat colour (P = 0.67), marbling (P = 0.70), all diseases (P = 0.64), bovine respiratory disease (P = 0.91), or mortalities (P = 1.0). Cattle fed FeedMAX 15 reached the market specifications for body weight and fat depth in fewer mean days (P = 0.0001), had a greater average daily gain (P = 0.05), a lower feed conversion ratio (P = 0.05) and whiter fat (P < 0.0001). Feeding the humic and fulvic acid complex, FeedMAX 15, at 0.055 g per kg body weight per day, can increase growth rate and feed conversion efficiency in feedlot cattle.

H-binding of size- and polarity-fractionated soil and lignite humic acids after removal of metal and ash components

USGS Publications Warehouse

Drosos, Marios; Leenheer, Jerry A.; Avgeropoulos, Apostolos; Deligiannakis, Yiannis

2014-01-01

A fractionation technique, combining dialysis removal of metal and ash components with hydrofluoric acid and pH 10 citrate buffer followed by chromatography of dialysis permeate on XAD-8 resin at decreasing pH values, has been applied to lignite humic acid (lignite-HA) and soil humic acid (soil-HA). H-binding data and non ideal competitive adsorption-Donnan model parameters were obtained for the HA fractions by theoretical analysis of H-binding data which reveal a significant increase of the carboxyl and the phenolic charge for the lignite-HA fractions vs. the parental lignite humic acid (LParentalHA). The fractionated lignite-HA material consisted mainly of permeate fractions, some of which were fulvic acid-like. The fractionated soil-HA material consisted mainly of large macromolecular structures that did not permeate the dialysis membrane during deashing. Chargeable groups had comparable concentrations in soil-HA fractions and parental soil humic acid (SParentalHA), indicating minimal interference of ash components with carboxyl and phenolic (and/or enolic) groups. Fractionation of HA, combined with theoretical analysis of H-binding, can distinguish the supramolecular vs. macromolecular nature of fractions within the same parental HA.

H-binding of size- and polarity-fractionated soil and lignite humic acids after removal of metal and ash components.

PubMed

Drosos, Marios; Leenheer, Jerry A; Avgeropoulos, Apostolos; Deligiannakis, Yiannis

2014-03-01

A fractionation technique, combining dialysis removal of metal and ash components with hydrofluoric acid and pH 10 citrate buffer followed by chromatography of dialysis permeate on XAD-8 resin at decreasing pH values, has been applied to lignite humic acid (lignite-HA) and soil humic acid (soil-HA). H-binding data and non ideal competitive adsorption-Donnan model parameters were obtained for the HA fractions by theoretical analysis of H-binding data which reveal a significant increase of the carboxyl and the phenolic charge for the lignite-HA fractions vs. the parental lignite humic acid (LParentalHA). The fractionated lignite-HA material consisted mainly of permeate fractions, some of which were fulvic acid-like. The fractionated soil-HA material consisted mainly of large macromolecular structures that did not permeate the dialysis membrane during deashing. Chargeable groups had comparable concentrations in soil-HA fractions and parental soil humic acid (SParentalHA), indicating minimal interference of ash components with carboxyl and phenolic (and/or enolic) groups. Fractionation of HA, combined with theoretical analysis of H-binding, can distinguish the supramolecular vs. macromolecular nature of fractions within the same parental HA.

Two-dimensional correlation spectroscopic analysis on the interaction between humic acids and aluminum coagulant.

PubMed

Jin, Pengkang; Song, Jina; Wang, Xiaochang C; Jin, Xin

2018-02-01

In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral pH. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at pH5. At pH5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by co-precipitation. Meanwhile, at pH7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al(OH) 3 . Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of COOH>COO - >NH deformation of amide II>aliphatic hydroxyl COH at pH5, and COO - >aliphatic hydroxyl COH at pH7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants. Copyright © 2017. Published by Elsevier B.V.

Effect of humic acid (HA) on sulfonamide sorption by biochars.

PubMed

Lian, Fei; Sun, Binbin; Chen, Xi; Zhu, Lingyan; Liu, Zhongqi; Xing, Baoshan

2015-09-01

Effect of quantity and fractionation of loaded humic acid (HA) on biochar sorption for sulfonamides was investigated. The HA was applied in two different modes, i.e. pre-coating and co-introduction with sorbate. In pre-coating mode, the polar fractions of HA tended to interact with low-temperature biochars via H-bonding, while the hydrophobic fractions were likely to be adsorbed by high-temperature biochars through hydrophobic and π-π interactions, leading to different composition and structure of the HA adlayers. The influences of HA fractionation on biochar sorption for sulfonamides varied significantly, depending on the nature of interaction between HA fraction and sorbate. Meanwhile, co-introduction of HA with sulfonamides revealed that the effect of HA on sulfonamide sorption was also dependent on HA concentration. These findings suggest that the amount and fractionation of adsorbed HA are tailored by the surface properties of underlying biochars, which differently affect the sorption for organic contaminants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling the binding of fulvic acid by goethite: the speciation of adsorbed FA molecules

NASA Astrophysics Data System (ADS)

Filius, Jeroen D.; Meeussen, Johannes C. L.; Lumsdon, David G.; Hiemstra, Tjisse; van Riemsdijk, Willem H.

2003-04-01

Under natural conditions, the adsorption of ions at the solid-water interface may be strongly influenced by the adsorption of organic matter. In this paper, we describe the adsorption of fulvic acid (FA) by metal(hydr)oxide surfaces with a heterogeneous surface complexation model, the ligand and charge distribution (LCD) model. The model is a self-consistent combination of the nonideal competitive adsorption (NICA) equation and the CD-MUSIC model. The LCD model can describe simultaneously the concentration, pH, and salt dependency of the adsorption with a minimum of only three adjustable parameters. Furthermore, the model predicts the coadsorption of protons accurately for an extended range of conditions. Surface speciation calculations show that almost all hydroxyl groups of the adsorbed FA molecules are involved in outer sphere complexation reactions. The carboxylic groups of the adsorbed FA molecule form inner and outer sphere complexes. Furthermore, part of the carboxylate groups remain noncoordinated and deprotonated.

Isoproturon Reappearance after Photosensitized Degradation in the Presence of Triplet Ketones or Fulvic Acids.

PubMed

Yuan, Chenyi; Chakraborty, Mrinal; Canonica, Silvio; Weavers, Linda K; Hadad, Christopher M; Chin, Yu-Ping

2016-11-15

Isoproturon (IPU) is a phenylurea herbicide used to control broad-leaf grasses on grain fields. Photosensitized transformation induced by excited triplet states of dissolved organic matter ( 3 DOM*) has been identified as an important degradation pathway for IPU in sunlit waters, but the reappearance of IPU in the absence of light is observed after the initial photolysis. In this study, we elucidate the kinetics of this photodegradation and dark-reappearance cycling of IPU in the presence of DOM proxies (aromatic ketones and reference fulvic acids). Using mass spectrometry and nuclear magnetic resonance spectroscopic techniques, a semi-stable intermediate (IPU int ) was found to be responsible for IPU reversion and was identified as a hydroperoxyl derivative of IPU. IPU int is photogenerated from incorporation of diatomic oxygen to IPU and is subjected to thermolysis whose rate depends on temperature, pH, the presence of DOM, and inorganic ions. These results are important to understand the overall aquatic fate of IPU and structurally similar compounds under diurnal conditions.

Experimental evidence for ternary colloid-facilitated transport of Th(IV) with hematite (α-Fe2O3) colloids and Suwannee River fulvic acid.

PubMed

Emerson, Hilary P; Hickok, Katherine A; Powell, Brian A

2016-12-01

Previous field experiments have suggested colloid-facilitated transport via inorganic and organic colloids as the primary mechanism of enhanced actinide transport in the subsurface at former nuclear weapons facilities. In this work, research was guided by the hypothesis that humic substances can enhance tetravalent actinide (An(IV)) migration by coating and mobilizing natural colloids in environmental systems and increasing An(IV) sorption to colloids. This mechanism is expected to occur under relatively acidic conditions where organic matter can sorb and coat colloid surfaces and facilitate formation of ternary colloid-ligand-actinide complexes. The objective of this work was to examine Th transport through packed columns in the presence of hematite colloids and/or Suwannee River fulvic acid (SRFA). In the presence of SRFA, with or without hematite colloids, significant transport (>60% recovery within the effluent) of thorium occurred through quartz columns. It is notable that the SRFA contributed to increased transport of both Th and hematite colloids, while insignificant transport occurred in the absence of fulvic acid. Further, in the presence of a natural sandy sediment (as opposed to pure quartz), transport is negligible in the presence of SRFA due to interactions with natural, clay-sized sediment coatings. Moreover, this data shows that the transport of Th through quartz columns is enhanced in ternary Th-colloid-SRFA and binary Th-SRFA systems as compared to a system containing only Th. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of Tillage, Cropping Management, and Nitrogen Source on Humic, Fulvic, and Water-Extractable Organic Matter Fractions: A Fluorescence Study

USDA-ARS?s Scientific Manuscript database

The characterization of organic matter in agroecosystems is important due to its involvement in many soil ecosystem processes. Humic acid, fulvic acid, and water-extractable organic matter from a nine-year agroecosystem study investigating the effects of tillage, cropping system, and N source were c...

Preferential adsorption of fluorescing fulvic and humic acid components on activated carbon using flow field-flow fractionation analysis.

PubMed

Schmit, Kathryn H; Wells, Martha J M

2002-02-01

Activated carbon treatment of drinking water is used to remove natural organic matter (NOM) precursors that lead to the formation of disinfection byproducts. The innate hydrophobic nature and macromolecular size of NOM render it amenable to sorption by activated carbon. Batch equilibrium and minicolumn breakthrough adsorption studies were performed using granular activated carbon to treat NOM-contaminated water. Ultraviolet (UV) absorption spectroscopy and flow field-flow fractionation analysis using tandem diode-array and fluorescence detectors were used to monitor the activated carbon sorption of NOM. Using these techniques, it was possible to study activated carbon adsorption properties of UV absorbing, fluorescing and nonfluorescing, polyelectrolytic macromolecules fractionated from the total macromolecular and nonmacromolecular composition of NOM. Adsorption isotherms were constructed at pH 6 and pH 9. Data were described by the traditional and modified Freundlich models. Activated carbon capacity and adsorbability were compared among fractionated molecular subsets of fulvic and humic acids. Preferential adsorption (or adsorptive fractionation) of polyelectrolytic, fluorescing fulvic and humic macromolecules on activated carbon was observed. The significance of observing preferential adsorption on activated carbon of fluorescing macromolecular components relative to nonfluorescing components is that this phenomenon changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the composition that existed in the aqueous phase prior to adsorption. Likewise, it changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the adsorbed phase. This research increases our understanding of NOM interactions with activated carbon which may lead to improved methods of potable water production.

Fragmentation studies of fulvic acids using collision induced dissociation fourier transform ion cyclotron resonance mass spectrometry.

PubMed

Witt, Matthias; Fuchser, Jens; Koch, Boris P

2009-04-01

The complex natural organic matter standard Suwannee river fulvic acid (SRFA) was analyzed by negative ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR MS) using on-resonance collision induced dissociation (CID) of single ultrahigh resolved mass peaks in the ICR cell. Molecular formula assignment of precursor masses resulted in exactly one molecular formula for each of the peaks. Analyses of the corresponding fragment spectra and comparison to different standard substances revealed specific neutral losses and fragmentation patterns which result in structures consisting of a high degree of carboxyl- and fewer hydroxyl groups. The comparison of fragmented mass peaks within different pseudohomologous series (CH(2)-series, and CH(4) vs O exchange) suggested structurally based differences between these series. CID FTICR MS allowed isolating single mass peaks in a very complex natural organic matter spectrum. Subsequently, fragmentation gave structural insights into this material. Our results suggest that the structural diversity in complex humic substances is not as high as expected.

Effect of fulvic acid surface coatings on plutonium sorption and desorption kinetics on goethite

DOE PAGES

Tinnacher, Ruth M.; Begg, James D.; Mason, Harris; ...

2015-01-21

The rates and extent of plutonium (Pu) sorption and desorption onto mineral surfaces are important parameters for predicting Pu mobility in subsurface environments. The presence of natural organic matter, such as fulvic acid (FA), may influence these parameters. We investigated the effects of FA on Pu(IV) sorption/desorption onto goethite in two scenarios: when FA was (1) initially present in solution or (2) found as organic coatings on the mineral surface. A low pH was used to maximize FA coatings on goethite. Experiments were combined with kinetic modeling and speciation calculations to interpret variations in Pu sorption rates in the presencemore » of FA. Our results indicate that FA can change the rates and extent of Pu sorption onto goethite at pH 4. Differences in the kinetics of Pu sorption were observed as a function of the concentration and initial form of FA. The fraction of desorbed Pu decreased in the presence of FA, indicating that organic matter can stabilize sorbed Pu on goethite. These results suggest that ternary Pu–FA–mineral complexes could enhance colloid-facilitated Pu transport. In conclusion, more representative natural conditions need to be investigated to quantify the relevance of these findings.« less

Survival and reproduction of some nematodes as affected by muck and organic acids.

PubMed

Elmiligy, I A; Norton, D C

1973-01-01

Fulvic, humic, acetic, N-bulyric, formic, lactic, and propionic acids were inhibitory to the survival or reproduction of Aphelenchus avenae, Aphelenchoides goodeyi, Helicotylenchus pseudorobustus, Meloidogyne hapla or Xiphinema americanum. Reproduction of H. pseudorobustus and M. hapla significantly increased with increasing amounts of muck added to sand, and with the initial amount of nematode inoculum. All acids except humic and fulvic were lethal, in vitro, to all nematode species tested. When A. goodeyi was treated with fulvic acid, reproduction was reduced significantly when compared with sodium humate or water treatments. Treatment of H. pseudorobustus with fulvic acid (pH 3.5) resulted in a greater reduction in reproduction in soil than did treatment with humic acid (pH 3.5).

3D bioprinting of methacrylated hyaluronic acid (MeHA) hydrogel with intrinsic osteogenicity.

PubMed

Poldervaart, Michelle T; Goversen, Birgit; de Ruijter, Mylene; Abbadessa, Anna; Melchels, Ferry P W; Öner, F Cumhur; Dhert, Wouter J A; Vermonden, Tina; Alblas, Jacqueline

2017-01-01

In bone regenerative medicine there is a need for suitable bone substitutes. Hydrogels have excellent biocompatible and biodegradable characteristics, but their visco-elastic properties limit their applicability, especially with respect to 3D bioprinting. In this study, we modified the naturally occurring extracellular matrix glycosaminoglycan hyaluronic acid (HA), in order to yield photo-crosslinkable hydrogels with increased mechanical stiffness and long-term stability, and with minimal decrease in cytocompatibility. Application of these tailor-made methacrylated hyaluronic acid (MeHA) gels for bone tissue engineering and 3D bioprinting was the subject of investigation. Visco-elastic properties of MeHA gels, measured by rheology and dynamic mechanical analysis, showed that irradiation of the hydrogels with UV light led to increased storage moduli and elastic moduli, indicating increasing gel rigidity. Subsequently, human bone marrow derived mesenchymal stromal cells (MSCs) were incorporated into MeHA hydrogels, and cell viability remained 64.4% after 21 days of culture. Osteogenic differentiation of MSCs occurred spontaneously in hydrogels with high concentrations of MeHA polymer, in absence of additional osteogenic stimuli. Addition of bone morphogenetic protein-2 (BMP-2) to the culture medium further increased osteogenic differentiation, as evidenced by increased matrix mineralisation. MeHA hydrogels demonstrated to be suitable for 3D bioprinting, and were printed into porous and anatomically shaped scaffolds. Taken together, photosensitive MeHA-based hydrogels fulfilled our criteria for cellular bioprinted bone constructs within a narrow window of concentration.

3D bioprinting of methacrylated hyaluronic acid (MeHA) hydrogel with intrinsic osteogenicity

PubMed Central

Poldervaart, Michelle T.; Goversen, Birgit; de Ruijter, Mylene; Abbadessa, Anna; Melchels, Ferry P. W.; Öner, F. Cumhur; Dhert, Wouter J. A.; Vermonden, Tina

2017-01-01

In bone regenerative medicine there is a need for suitable bone substitutes. Hydrogels have excellent biocompatible and biodegradable characteristics, but their visco-elastic properties limit their applicability, especially with respect to 3D bioprinting. In this study, we modified the naturally occurring extracellular matrix glycosaminoglycan hyaluronic acid (HA), in order to yield photo-crosslinkable hydrogels with increased mechanical stiffness and long-term stability, and with minimal decrease in cytocompatibility. Application of these tailor-made methacrylated hyaluronic acid (MeHA) gels for bone tissue engineering and 3D bioprinting was the subject of investigation. Visco-elastic properties of MeHA gels, measured by rheology and dynamic mechanical analysis, showed that irradiation of the hydrogels with UV light led to increased storage moduli and elastic moduli, indicating increasing gel rigidity. Subsequently, human bone marrow derived mesenchymal stromal cells (MSCs) were incorporated into MeHA hydrogels, and cell viability remained 64.4% after 21 days of culture. Osteogenic differentiation of MSCs occurred spontaneously in hydrogels with high concentrations of MeHA polymer, in absence of additional osteogenic stimuli. Addition of bone morphogenetic protein-2 (BMP-2) to the culture medium further increased osteogenic differentiation, as evidenced by increased matrix mineralisation. MeHA hydrogels demonstrated to be suitable for 3D bioprinting, and were printed into porous and anatomically shaped scaffolds. Taken together, photosensitive MeHA-based hydrogels fulfilled our criteria for cellular bioprinted bone constructs within a narrow window of concentration. PMID:28586346

Elemental composition and functional groups in soil labile organic matter fractions

USDA-ARS?s Scientific Manuscript database

Labile organic matter fractions are major components involved in nutrient cycle in soil. In this chapter, we examine three labile organic matter fraction: light fraction (LF), humic acid (HA) and fulvic acid (HA) in Alabama cotton soils (ultisol) amended with chemical fertilizer (NH4NO3) and poult...

Intra-articular Hyaluronic Acid (HA) and Platelet Rich Plasma (PRP) injection versus Hyaluronic acid (HA) injection alone in Patients with Grade III and IV Knee Osteoarthritis (OA): A Retrospective Study on Functional Outcome.

PubMed

Saturveithan, C; Premganesh, G; Fakhrizzaki, S; Mahathir, M; Karuna, K; Rauf, K; William, H; Akmal, H; Sivapathasundaram, N; Jaspreet, K

2016-07-01

Introduction: Intra-articular hyaluronic acid (HA) is widely utilized in the treatment of knee osteoarthritis whereas platelet rich plasma (PRP) enhances the regeneration of articular cartilage. This study analyses the efficacy of HA and PRP in grade III and IV knee osteoarthritis. Methodology: This is a cross sectional study with retrospective review of 64 patients (101 knees) which includes 56 knees injected with HA+ PRP, and 45 knees with HA only. Results: During the post six months International Knee Documentation Committee (IKDC) evaluation, HA+PRP group showed marked improvement of 24.33 compared to 12.15 in HA group. Decrement in visual analogue score (VAS) in HA+PRP was 1.9 compared to 0.8 in HA group. Conclusion: We propose intra-articular HA and PRP injections as an optional treatment modality in Grade III and IV knee osteoarthritis in terms of functional outcome and pain control for up to six months when arthroplasty is not an option.

Intra-articular Hyaluronic Acid (HA) and Platelet Rich Plasma (PRP) injection versus Hyaluronic acid (HA) injection alone in Patients with Grade III and IV Knee Osteoarthritis (OA): A Retrospective Study on Functional Outcome

PubMed Central

Premganesh, G; Fakhrizzaki, S; Mahathir, M; Karuna, K; Rauf, K; William, H; Akmal, H; Sivapathasundaram, N; Jaspreet, K

2016-01-01

Introduction: Intra-articular hyaluronic acid (HA) is widely utilized in the treatment of knee osteoarthritis whereas platelet rich plasma (PRP) enhances the regeneration of articular cartilage. This study analyses the efficacy of HA and PRP in grade III and IV knee osteoarthritis. Methodology: This is a cross sectional study with retrospective review of 64 patients (101 knees) which includes 56 knees injected with HA+ PRP, and 45 knees with HA only. Results: During the post six months International Knee Documentation Committee (IKDC) evaluation, HA+PRP group showed marked improvement of 24.33 compared to 12.15 in HA group. Decrement in visual analogue score (VAS) in HA+PRP was 1.9 compared to 0.8 in HA group. Conclusion: We propose intra-articular HA and PRP injections as an optional treatment modality in Grade III and IV knee osteoarthritis in terms of functional outcome and pain control for up to six months when arthroplasty is not an option. PMID:28435559

The enhanced anti-tissue adhesive effect of injectable pluronic-HA hydrogel by poly(γ-glutamic acid).

PubMed

Kim, Manse; Hwang, Youngmin; Tae, Giyoong

2016-12-01

The stability of tissue barrier in physiological condition is a key factor to isolate the damaged site from adjacent tissue for anti-tissue adhesion. Although pluronic or pluronic-hyaluronic acid (HA) hydrogel as an injectable formulation can prevent tissue adhesion at the injection site, the anti-tissue adhesion effect is limited due to its poor stability. Herein, we prepared tissue barrier formulations composed of pluronic F127 (F127) and HA mixture (F127-HA) and the effect of the addition of poly(γ-glutamic acid) (PGA) was characterized. All of F127, HA, and F127-HA mixture showed the poor in vitro residence stability less than 3 days. However, by adding PGA into F127-HA mixture, their stability was significantly enhanced by the control of the molecular weight and concentration of PGA. Thus, F127-HA with 10wt% PGA (2000kDa) showed the long-term stability over 10 days. Similarly, the enhanced stability of F127-HA with PGA resulted in the enhanced and excellent in vivo anti-tissue adhesion effect, evidenced by histological analysis and grading of tissue adhesion. Therefore, F127-HA containing PGA could be applied as an efficient injectable tissue barrier for anti-tissue adhesion. Copyright © 2016 Elsevier B.V. All rights reserved.

Bond Dissociation Free Energies (BDFEs) of the Acidic H-A Bonds in HA(*)(-) Radical Anions by Three Different Pathways.

PubMed

Zhao, Yongyu; Bordwell, Frederick G.

1996-09-20

Cleavage of radical anions, HA(*)(-), have been considered to give either H(*) + A(-) (path a) or H(-) + A(*) (path b), and factors determining the preferred mode of cleavage have been discussed. It is conceivable that cleavage to give a proton and a radical dianion, HA(*)(-) right harpoon over left harpoon H(+) + A(*)(2)(-) (path c), might also be feasible. A method, based on a thermodynamic cycle, to estimate the bond dissociation free energy (BDFE) by path c has been devised. Comparison of the BDFEs for cleavage of the radical anions derived from 24 nitroaromatic OH, SH, NH, and CH acids by paths a, b, c has shown that path c is favored thermodynamically.

[Effects of Fulvic Acid on Absorption and Form Distribution of Heavy Metals on Sediments].

PubMed

Li, Yu-qing; He, Jiang; Lü, Chang-wei; Fan, Ming-de; Wang, Wei; Zhang, Rui-qing; Xie, Zhi- lei; Wang, Jing-hua; Yu, Bo; En, He; Ding, Tao

2016-03-15

Based on the extracted fulvic acid (FA) from Lake Wuliangsuhai sediments by sequential alkali extraction, this work studied the effects of FA on the adsorption and fraction distribution of heavy metals (HM) on sediments using original sediments and sediments treated with 30% H₂O₂ as adsorbents. The results showed both organic matter and FA had effects on the HM adsorption onto sediments; The treatments of FA-free conditions and the sediments treated by H₂O₂ showed relatively strong influence on Cu²⁺ adsorption, which decreased the Cu²⁺ adsorption by 17.85%. With the increasing FA addition, the adsorption percentage of HM on both types of sediments showed gradually decreasing trends, with the order of Cu²⁺ > Cd²⁺ > Zn²⁺ > Pb²⁺; when the FA content was more than 5% , FA became the governing factor on the decreasing adsorption percentage of HM. With increasing FA addition, forms distribution of HM showed significant changes in both types of sediments; i. e. FA additions showed significant negative and positive correlations with percentages of metals bound to carbonates and organic matter, respectively, since the FA addition increased the H⁺ concentration of the system, in which H⁺ could activate the metals bound to carbonate from the sediments. As an organophilic weak element, the fraction percentage of Cd bound to organic matter was the lowest with the minimal changes.

Elastin-like protein-hyaluronic acid (ELP-HA) hydrogels with decoupled mechanical and biochemical cues for cartilage regeneration.

PubMed

Zhu, Danqing; Wang, Huiyuan; Trinh, Pavin; Heilshorn, Sarah C; Yang, Fan

2017-05-01

Hyaluronic acid (HA) is a major component of cartilage extracellular matrix and is an attractive material for use as 3D injectable matrices for cartilage regeneration. While previous studies have shown the promise of HA-based hydrogels to support cell-based cartilage formation, varying HA concentration generally led to simultaneous changes in both biochemical cues and stiffness. How cells respond to the change of biochemical content of HA remains largely unknown. Here we report an adaptable elastin-like protein-hyaluronic acid (ELP-HA) hydrogel platform using dynamic covalent chemistry, which allows variation of HA concentration without affecting matrix stiffness. ELP-HA hydrogels were created through dynamic hydrazone bonds via the reaction between hydrazine-modified ELP (ELP-HYD) and aldehyde-modified HA (HA-ALD). By tuning the stoichiometric ratio of aldehyde groups to hydrazine groups while maintaining ELP-HYD concentration constant, hydrogels with variable HA concentration (1.5%, 3%, or 5%) (w/v) were fabricated with comparable stiffness. To evaluate the effects of HA concentration on cell-based cartilage regeneration, chondrocytes were encapsulated within ELP-HA hydrogels with varying HA concentration. Increasing HA concentration led to a dose-dependent increase in cartilage-marker gene expression and enhanced sGAG deposition while minimizing undesirable fibrocartilage phenotype. The use of adaptable protein hydrogels formed via dynamic covalent chemistry may be broadly applicable as 3D scaffolds with decoupled niche properties to guide other desirable cell fates and tissue repair. Copyright © 2017 Elsevier Ltd. All rights reserved.

Elastin-like Protein-Hyaluronic acid (ELP-HA) Hydrogels with Decoupled Mechanical and Biochemical cues for Cartilage Regeneration

PubMed Central

Zhu, Danqing; Wang, Huiyuan; Trinh, Pavin; Heilshorn, Sarah C.; Yang, Fan

2018-01-01

Hyaluronic acid (HA) is a major component of cartilage extracellular matrix and is an attractive material for use as 3D injectable matrices for cartilage regeneration. While previous studies have shown the promise of HA-based hydrogels to support cell-based cartilage formation, varying HA concentration generally led to simultaneous changes in both biochemical cues and stiffness. How cells respond to the change of biochemical content of HA remains largely unknown. Here we report an adaptable elastin-like protein-hyaluronic acid (ELP-HA) hydrogel platform using dynamic covalent chemistry, which allows varyiation of HA concentration without affecting matrix stiffness. ELP-HA hydrogels were created through dynamic hydrazone bonds via the reaction between hydrazine-modified ELP (ELP-HYD) and aldehyde-modified HA (HA-ALD). By tuning the stoichiometric ratio of aldehyde groups to hydrazine groups while maintaining ELP-HYD concentration constant, hydrogels with variable HA concentration (1.5%, 3%, or 5%) (w/v) were fabricated with comparable stiffness. To evaluate the effects of HA concentration on cell-based cartilage regeneration, chondrocytes were encapsulated within ELP-HA hydrogels with varying HA concentration. Increasing HA concentration led to a dose-dependent increase in cartilage-marker gene expression and enhanced sGAG deposition while minimizing undesirable fibrocartilage phenotype. The use of adaptable protein hydrogels formed via dynamic covalent chemistry may be broadly applicable as 3D scaffolds with decoupled niche properties to guide other desirable cell fates and tissue repair. PMID:28268018

Green synthesis of low-toxicity graphene-fulvic acid with an open band gap enhances demethylation of methylmercury.

PubMed

Hu, Xiangang; Mu, Li; Lu, Kaicheng; Kang, Jia; Zhou, Qixing

2014-06-25

The demethylation of methylmercury has received substantial attention. Here, a novel chemical method for the demethylation of methylmercury is proposed. The low-toxicity graphene-fulvic acid (FA, a ubiquitous material in the environment) was synthesized without the use of a chemical reagent. The hybridized graphene-FA presented an indirect open band gap of 2.25-2.87 eV as well as adequate aqueous dispersion. More importantly, the hybridized graphene-FA exhibited 6- and 10-fold higher photocatalytic efficiencies for the demethylation of methylmercury than FA and free FA with graphene, respectively. This result implies that immobilized, rather than free, FA accelerated the catalysis. Furthermore, inorganic mercuric ion, elemental mercury, and mercuric oxide were identified as the primary demethylation products. For free FA with graphene, graphene quenches the excited-state FA, inhibiting the demethylation by electron transfer. In contrast, the graphene of the self-assembled graphene-FA serves as an electron reservoir, causing electron-hole pair separation. Graphene-FA showed a negligible toxicity toward microalgae compared to graphene. The above results reveal that the green synthesis of graphene and organic molecules is a convenient strategy for obtaining effective cocatalysts.

Fractal analysis of polyferric chloride-humic acid (PFC-HA) flocs in different topological spaces.

PubMed

Wang, Yili; Lu, Jia; Baiyu, Du; Shi, Baoyou; Wang, Dongsheng

2009-01-01

The fractal dimensions in different topological spaces of polyferric chloride-humic acid (PFC-HA) flocs, formed in flocculating different kinds of humic acids (HA) water at different initial pH (9.0, 7.0, 5.0) and PFC dosages, were calculated by effective density-maximum diameter, image analysis, and N2 absorption-desorption methods, respectively. The mass fractal dimensions (Df) of PFC-HA flocs were calculated by bi-logarithm relation of effective density with maximum diameter and Logan empirical equation. The Df value was more than 2.0 at initial pH of 7.0, which was 11% and 13% higher than those at pH 9.0 and 5.0, respectively, indicating the most compact flocs formed in flocculated HA water at initial pH of 7.0. The image analysis for those flocs indicates that after flocculating the HA water at initial pH greater than 7.0 with PFC flocculant, the fractal dimensions of D2 (logA vs. logdL) and D3 (logVsphere VS. logdL) of PFC-HA flocs decreased with the increase of PFC dosages, and PFC-HA flocs showed a gradually looser structure. At the optimum dosage of PFC, the D2 (logA vs. logdL) values of the flocs show 14%-43% difference with their corresponding Df, and they even had different tendency with the change of initial pH values. However, the D2 values of the flocs formed at three different initial pH in HA solution had a same tendency with the corresponding Dr. Based on fractal Frenkel-Halsey-Hill (FHH) adsorption and desorption equations, the pore surface fractal dimensions (Ds) for dried powders of PFC-HA flocs formed in HA water with initial pH 9.0 and 7.0 were all close to 2.9421, and the Ds values of flocs formed at initial pH 5.0 were less than 2.3746. It indicated that the pore surface fractal dimensions of PFC-HA flocs dried powder mainly show the irregularity from the mesopore-size distribution and marcopore-size distribution.

Adsorption of Eu(III) onto TiO2: effect of pH, concentration, ionic strength and soil fulvic acid.

PubMed

Tan, Xiaoli; Fang, Ming; Li, Jiaxing; Lu, Yi; Wang, Xiangke

2009-08-30

The effects of pH, initial Eu(III) concentration, ionic strength and fulvic acid (FA) on the adsorption of Eu(III) on TiO(2) are investigated by using batch techniques. The results indicate that the presence of FA strongly enhances the adsorption of Eu(III) on TiO(2) at low pH values. Besides, the adsorption of Eu(III) on TiO(2) is significantly dependent on pH values and independent of ionic strength. The adsorption of Eu(III) on TiO(2) is attributed to inner-sphere surface complexation. The diffuse layer model (DLM) is applied to simulate the adsorption data, and fits the experimental data well with the aid of FITEQL 3.2. X-ray photoelectron spectroscopy (XPS) is performed to study the species of Eu(III) adsorbed on the surfaces of TiO(2)/FA-TiO(2) hybrids at a molecular level, which suggest that FA act as "bridge" between Eu(III) and TiO(2) particles to enhance the ability to adsorb Eu(III) in solution.

The novel kinetics expression of Cadmium (II) removal using green adsorbent horse dung humic acid (Hd-Ha)

NASA Astrophysics Data System (ADS)

Basuki, Rahmat; Santosa, Sri Juari; Rusdiarso, Bambang

2017-03-01

Humic acid from dry horse dung powder has been prepared and this horse dung humic acid (HD-HA) was then applied as a sorbent to adsorb Cadmium(II) from a solution. Characterization of HD-HA was conducted by detection of its functional group, UV-Vis spectra, ash level, and total acidity. Result of the work showed that HD-HA had similar character compared with peat soil humic acid (PS-HA) and previous researchers. The adsorption study of this work was investigated by batch experiment in pH 5. The thermodynamics parameters in this work were determined by the Langmuir isotherm model for monolayer sorption and Freundlich isotherm model multilayer sorption. Monolayer sorption capacity (b) for HD-HA was 1.329 × 10-3 mol g-1, equilibrium constant (K) was 5.651 (mol/L)-1, and multilayer sorption capacity was 2.646 × 10-2 mol g-1. The kinetics parameters investigated in this work were determined by the novel kinetics expression resulted from the mathematical derivation the availability of binding sites of sorbent. Adsorption rate constant (ka) from this novel expression was 43.178 min-1 (mol/L)-1 and desorption rate constant (kd) was 1.250 × 10-2 min-1. Application of the kinetics model on sorption Cd(II) onto HD-HA showed the nearly all of models gave a good linearity. However, only this proposed kinetics expression has good relation with Langmuir model. The novel kinetics expression proposed in this paper seems to be more realistic and reasonable and close to the experimental real condition because the value of ka/kd (3452 (mol/L)-1) was fairly close with K from Langmuir isotherm model (5651 (mol/L)-1). Comparison of this novel kinetics expression with well-known Lagergren pseudo-first order kinetics and Ho pseudo-second order kinetics was also critically discussed in this paper.

Sugar-induced conformational change found in the HA-33/HA-17 trimer of the botulinum toxin complex.

PubMed

Sagane, Yoshimasa; Hayashi, Shintaro; Matsumoto, Takashi; Miyashita, Shin-Ichiro; Inui, Ken; Miyata, Keita; Yajima, Shunsuke; Suzuki, Tomonori; Hasegawa, Kimiko; Yamano, Akihito; Nishikawa, Atsushi; Ohyama, Tohru; Watanabe, Toshihiro; Niwa, Koichi

2013-08-30

Large-sized botulinum toxin complex (L-TC) is formed by conjugation of neurotoxin, nontoxic nonhemagglutinin and hemagglutinin (HA) complex. The HA complex is formed by association of three HA-70 molecules and three HA-33/HA-17 trimers, comprised of a single HA-17 and two HA-33 proteins. The HA-33/HA-17 trimer isolated from serotype D L-TC has the ability to bind to and penetrate through the intestinal epithelial cell monolayer in a sialic acid-dependent manner, and thus it plays an important role in toxin delivery through the intestinal cell wall. In this study, we determined the solution structure of the HA-33/HA-17 trimer by using small-angle X-ray scattering (SAXS). The SAXS image of HA-33/HA-17 exhibited broadly similar appearance to the crystal image of the complex. On the other hand, in the presence of N-acetylneuraminic acid, glucose and galactose, the solution structure of the HA-33/HA-17 trimer was drastically altered compared to the structure in the absence of the sugars. Sugar-induced structural change of the HA-33/HA-17 trimer may contribute to cell binding and subsequent transport across the intestinal cell layer. Copyright © 2013 Elsevier Inc. All rights reserved.

Characterization of Three Novel Fatty Acid- and Retinoid-Binding Protein Genes (Ha-far-1, Ha-far-2 and Hf-far-1) from the Cereal Cyst Nematodes Heterodera avenae and H. filipjevi

PubMed Central

Peng, Huan; Luo, Shujie; Huang, Wenkun; Cui, Jiangkuan; Li, Xin; Kong, Lingan; Jiang, Daohong; Chitwood, David J.; Peng, Deliang

2016-01-01

Heterodera avenae and H. filipjevi are major parasites of wheat, reducing production worldwide. Both are sedentary endoparasitic nematodes, and their development and parasitism depend strongly on nutrients obtained from hosts. Secreted fatty acid- and retinol-binding (FAR) proteins are nematode-specific lipid carrier proteins used for nutrient acquisition as well as suppression of plant defenses. In this study, we obtained three novel FAR genes Ha-far-1 (KU877266), Ha-far-2 (KU877267), Hf-far-1 (KU877268). Ha-far-1 and Ha-far-2 were cloned from H. avenae, encoding proteins of 191 and 280 amino acids with molecular masses about 17 and 30 kDa, respectively and sequence identity of 28%. Protein Blast in NCBI revealed that Ha-FAR-1 sequence is 78% similar to the Gp-FAR-1 protein from Globodera pallida, while Ha-FAR-2 is 30% similar to Rs-FAR-1 from Radopholus similis. Only one FAR protein Hf-FAR-1was identified in H. filipjevi; it had 96% sequence identity to Ha-FAR-1. The three proteins are alpha-helix-rich and contain the conserved domain of Gp-FAR-1, but Ha-FAR-2 had a remarkable peptide at the C-terminus which was random-coil-rich. Both Ha-FAR-1 and Hf-FAR-1 had casein kinase II phosphorylation sites, while Ha-FAR-2 had predicted N-glycosylation sites. Phylogenetic analysis showed that the three proteins clustered together, though Ha-FAR-1 and Hf-FAR-1 adjoined each other in a plant-parasitic nematode branch, but Ha-FAR-2 was distinct from the other proteins in the group. Fluorescence-based ligand binding analysis showed the three FAR proteins bound to a fluorescent fatty acid derivative and retinol and with dissociation constants similar to FARs from other species, though Ha-FAR-2 binding ability was weaker than that of the two others. In situ hybridization detected mRNAs of Ha-far-1 and Ha-far-2 in the hypodermis. The qRT-PCR results showed that the Ha-far-1and Ha-far-2 were expressed in all developmental stages; Ha-far-1 expressed 70 times more than Ha-far-2 in

Characterization of Three Novel Fatty Acid- and Retinoid-Binding Protein Genes (Ha-far-1, Ha-far-2 and Hf-far-1) from the Cereal Cyst Nematodes Heterodera avenae and H. filipjevi.

PubMed

Qiao, Fen; Luo, Lilian; Peng, Huan; Luo, Shujie; Huang, Wenkun; Cui, Jiangkuan; Li, Xin; Kong, Lingan; Jiang, Daohong; Chitwood, David J; Peng, Deliang

2016-01-01

Heterodera avenae and H. filipjevi are major parasites of wheat, reducing production worldwide. Both are sedentary endoparasitic nematodes, and their development and parasitism depend strongly on nutrients obtained from hosts. Secreted fatty acid- and retinol-binding (FAR) proteins are nematode-specific lipid carrier proteins used for nutrient acquisition as well as suppression of plant defenses. In this study, we obtained three novel FAR genes Ha-far-1 (KU877266), Ha-far-2 (KU877267), Hf-far-1 (KU877268). Ha-far-1 and Ha-far-2 were cloned from H. avenae, encoding proteins of 191 and 280 amino acids with molecular masses about 17 and 30 kDa, respectively and sequence identity of 28%. Protein Blast in NCBI revealed that Ha-FAR-1 sequence is 78% similar to the Gp-FAR-1 protein from Globodera pallida, while Ha-FAR-2 is 30% similar to Rs-FAR-1 from Radopholus similis. Only one FAR protein Hf-FAR-1was identified in H. filipjevi; it had 96% sequence identity to Ha-FAR-1. The three proteins are alpha-helix-rich and contain the conserved domain of Gp-FAR-1, but Ha-FAR-2 had a remarkable peptide at the C-terminus which was random-coil-rich. Both Ha-FAR-1 and Hf-FAR-1 had casein kinase II phosphorylation sites, while Ha-FAR-2 had predicted N-glycosylation sites. Phylogenetic analysis showed that the three proteins clustered together, though Ha-FAR-1 and Hf-FAR-1 adjoined each other in a plant-parasitic nematode branch, but Ha-FAR-2 was distinct from the other proteins in the group. Fluorescence-based ligand binding analysis showed the three FAR proteins bound to a fluorescent fatty acid derivative and retinol and with dissociation constants similar to FARs from other species, though Ha-FAR-2 binding ability was weaker than that of the two others. In situ hybridization detected mRNAs of Ha-far-1 and Ha-far-2 in the hypodermis. The qRT-PCR results showed that the Ha-far-1and Ha-far-2 were expressed in all developmental stages; Ha-far-1 expressed 70 times more than Ha-far-2 in

Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

NASA Astrophysics Data System (ADS)

Wei, Wei; Yang, Lei; Zhong, Wenhui; Cui, Jing; Wei, Zhenggui

2015-03-01

In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (Xc = 0.23) and had better adsorption capacity for FA than those (Xc = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long term. Findings of the present work highlight the potential for using poorly crystalline HAP nanoparticles as an effective and recyclable adsorbent for FA removal from aqueous solution.

Conformational divergence in the HA-33/HA-17 trimer of serotype C and D botulinum toxin complex.

PubMed

Sagane, Yoshimasa; Hayashi, Shintaro; Akiyama, Tomonori; Matsumoto, Takashi; Hasegawa, Kimiko; Yamano, Akihito; Suzuki, Tomonori; Niwa, Koichi; Watanabe, Toshihiro; Yajima, Shunsuke

2016-08-05

Clostridium botulinum produces a large toxin complex (L-TC) comprising botulinum neurotoxin associated with auxiliary nontoxic proteins. A complex of 33- and 17-kDa hemagglutinins (an HA-33/HA-17 trimer) enhances L-TC transport across the intestinal epithelial cell layer via binding HA-33 to a sugar on the cell surface. At least two subtypes of serotype C/D HA-33 exhibit differing preferences for the sugars sialic acid and galactose. Here, we compared the three-dimensional structures of the galactose-binding HA-33 and HA-33/HA-17 trimers produced by the C-Yoichi strain. Comparisons of serotype C/D HA-33 sequences reveal a variable region with relatively low sequence similarity across the C. botulinum strains; the variability of this region may influence the manner of sugar-recognition by HA-33. Crystal structures of sialic acid- and galactose-binding HA-33 are broadly similar in appearance. However, small-angle X-ray scattering revealed distinct solution structures for HA-33/HA-17 trimers. A structural change in the C-terminal variable region of HA-33 might cause a dramatic shift in the conformation and sugar-recognition mode of HA-33/HA-17 trimer. Copyright © 2016 Elsevier Inc. All rights reserved.

Isolation of hydrophilic organic acids from water using nonionic macroporous resins

USGS Publications Warehouse

Aiken, G.R.; McKnight, Diane M.; Thorn, K.A.; Thurman, E.M.

1992-01-01

A method has been developed for the isolation of hydrophilic organic acids from aquatic environments using Amberlite* * Use of trade names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. XAD-4 resin. The method uses a two column array of XAD-8 and XAD-4 resins in series. The hydrophobic organic acids, composed primarily of aquatic fulvic acid, are removed from the sample on XAD-8, followed by the isolation of the more hydrophilic organic acids on XAD-4. For samples from a number of diverse environments, more of the dissolved organic carbon was isolated on the XAD-8 resin (23-58%) than on the XAD-4 resin (7-25%). For these samples, the hydrophilic acids have lower carbon and hydrogen contents, higher oxygen and nitrogen contents, and are lower in molecular weight than the corresponding fulvic acids. 13C NMR analyses indicate that the hydrophilic acids have a lower concentration of aromatic carbon and greater heteroaliphatic, ketone and carboxyl content than the fulvic acid. ?? 1992.

The duration of hyaluronidase and optimal timing of hyaluronic acid (HA) filler reinjection after hyaluronidase injection.

PubMed

Kim, H J; Kwon, S B; Whang, K U; Lee, J S; Park, Y L; Lee, S Y

2018-02-01

Hyaluronidase injection is a commonly performed treatment for overcorrection or misplacement of hyaluronic acid (HA) filler. Many patients often wants the HA filler reinjection after the use of hyaluronidase, though the optimal timing of reinjection of HA filler still remains unknown. To provide the optimal time interval between hyaluronidase injections and HA filler reinjections. 6 Sprague-Dawley rats were injected with single monophasic HA filler. 1 week after injection, the injected sites were treated with hyaluronidase. Then, HA fillers were reinjected sequentially with differing time intervals from 30 minutes to 14 days. 1 hour after the reinjection of the last HA filler, all injection sites were excised for histologic evaluation. 3 hours after reinjection of HA filler, the appearance of filler material became evident again, retaining its shape and volume. 6 hours after reinjection, the filler materials restored almost its original volume and there were no significant differences from the positive control. Our data suggest that the hyaluronidase loses its effect in dermis and subcutaneous tissue within 3-6 hours after the injection and successful engraftment of reinjected HA filler can be accomplished 6 hours after the injection.

FT-IR and C-13 NMR analysis of soil humic fractions from a long term cropping systems study

USDA-ARS?s Scientific Manuscript database

Increased knowledge of humic fractions is important due to its involvement in many soil ecosystem processes. Soil humic acid (HA) and fulvic acid (FA) from a nine-year agroecosystem study with different tillage, cropping system, and N source treatments were characterized using FT-IR andsolid-state ...

In situ study of binding of copper by fulvic acid: comparison of differential absorbance data and model predictions.

PubMed

Yan, Mingquan; Dryer, Deborah; Korshin, Gregory V; Benedetti, Marc F

2013-02-01

This study examined the binding of copper(II) by Suwannee River fulvic acid (SRFA) using the method of differential absorbance that was used at environmentally-relevant concentrations of copper and SRFA. The pH- and metal-differential spectra were processed via numeric deconvolution to establish commonalities seen in the changes of absorbance caused by deprotonation of SRFA and its interactions with copper(II) ions. Six Gaussian bands were determined to be present in both the pH- and Cu-differential spectra. Their maxima were located, in the order of increasing wavelengths at 208 nm, 242 nm, 276 nm, 314 nm, 378 nm and 551 nm. The bands with these maxima were denoted as A0, A1, A2, A3, A4 and A5, respectively. Properties of these bands were compared with those existing in the spectra of model compounds such as sulfosalicylic acid (SSA), tannic acid (TA), and polystyrenesulfonic acid-co-maleic acid (PSMA). While none of the features observed in differential spectra of the model compound were identical to those present in the case of SRFA, Gaussian bands A1, A3 and possibly A2 were concluded to be largely attributable to a combination of responses of salicylic- and polyhydroxyphenolic groups. In contrast, bands A4 and A5 were detected in the differential spectra of SRFA only. Their nature remains to be elucidated. To examine correlations between the amount of copper(II) bound by SRFA and changes of its absorbance, differential absorbances measured at indicative wavelengths 250 nm and 400 nm were compared with the total amount of SRFA-bound copper estimated based on Visual MINTEQ calculations. This examination showed that the differential absorbances of SRFA in a wide range of pH values and copper concentrations were strongly correlated with the concentration of SRFA-bound copper. The approach presented in this study can be used to generate in situ information concerning the nature of functional groups in humic substances engaged in interactions with metals ions. This

Effects of humic acids with different polarities on the photocatalytic activity of nano-TiO2 at environment relevant concentration.

PubMed

Wu, Wei; Shan, Guoqiang; Xiang, Qian; Zhang, Yinqing; Yi, Shujun; Zhu, Lingyan

2017-10-01

Large volume production and application of nano-TiO 2 make it inevitably release to natural waters and its environmental behaviors would be affected by natural organic matters. In this study, the mechanisms of humic acid (HA) affecting the photocatalytic performance of nano-TiO 2 were elucidated by using three HA fractions from the same source but with different polarities. Bulk HA was fractionated on a silica gel column to get three fractions with polarity increasing in the order of FA, FB and FC. FA was fulvic acid-like while FB and FC were humic acid-like. All the three fractions (at 0.1 mg/L) promoted the generation of hydroxyl radicals (OHs) by nano-TiO 2 , and thus in turn facilitated the photocatalytic degradation of bispheol A (BPA). FA and FC displayed a stronger promotion effect than FB and the bulk HA. Online in situ flow cell ATR-FTIR and XPS analyses indicated that HA fractions could form charge-transfer complex with nano-TiO 2 surface through the phenolic hydroxyl and carboxylic groups, which favored the separation of photogenerated electron-hole pairs. Through step methylation experiments, it was verified that the phenolic hydroxyl and carboxylic groups of HA fractions played important roles in promoting the photocatalytic performance of nano-TiO 2 , and the effect of carboxylic group was more significant than the phenolic hydroxyl group. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in redox properties of Humic Acid (HA) upon sorption to alumina

NASA Astrophysics Data System (ADS)

Orsetti, Silvia; Haderlein, Stefan B.; Visser, Anna-Neva

2014-05-01

The interaction between humic substances and soil minerals may change important properties and reactivity of the organic matter. In particular, we are interested whether changes in the redox properties of a HA (namely total electron exchange capacity and redox state) occur upon sorption to redox inactive minerals. Sorption of Pahokee Peat humic acid to Al2O3 was studied at pH value of 7.0 in batch experiments, at several HA/oxide ratio. All experiments were conducted in anoxic environment. The required equilibration time was determined by taking aliquots of the suspension at several time intervals and registering the UV-vis spectra of the supernatant; apparent sorption equilibrium (no decrease in UV-vis signal) was achieved after 5 days approximately. Both the suspension (mineral+sorbed HA, plus supernatant) and the supernatant after centrifugation were analyzed using mediated electrochemical techniques, and the electron donating and accepting capacities (EDC and EAC, respectively) were determined. In addition, SUVA was calculated for each batch. These preliminary results show a slight increase in the SUVA of the supernatant upon sorption, which would indicate a preferential sorption of more aliphatic fractions. Interestingly, the total electron exchange capacities (EEC) of the supernatants showed no significant differences to that of the stock HA, whereas the EEC of the whole suspension showed values up to twice the one from the stock HA. The EDC/EAC (which can be interpreted as a measure of the redox state of the sample) also showed same values for stock and supernatants, being the values of the whole suspensions towards the reduced side. Therefore, such preliminary results would indicate not a change in the redox properties of the dissolved HA, but only for the sorbed one. The sorbed fraction seems to present higher redox activity (higher EEC) and a more reduced state than the stock HA. Given the absence of redox transfer between the HA and the oxide, it could

Acid-base properties of humic substances from composted and thermally-dried sewage sludges and amended soils as determined by potentiometric titration and the NICA-Donnan model.

PubMed

Fernández, José M; Plaza, César; Senesi, Nicola; Polo, Alfredo

2007-09-01

The acid-base properties of humic acids (HAs) and fulvic acids (FAs) isolated from composted sewage sludge (CS), thermally-dried sewage sludge (TS), soils amended with either CS or TS at a rate of 80 t ha(-1)y(-1) for 3y and the corresponding unamended soil were investigated by use of potentiometric titrations. The non-ideal competitive adsorption (NICA)-Donnan model for a bimodal distribution of proton binding sites was fitted to titration data by use of a least-squares minimization method. The main fitting parameters of the NICA-Donnan model obtained for each HA and FA sample included site densities, median affinity constants and widths of affinity distributions for proton binding to low and high affinity sites, which were assumed to be, respectively, carboxylic- and phenolic-type groups. With respect to unamended soil HA and FA, the HAs and FAs from CS, and especially TS, were characterized by smaller acidic functional group contents, larger proton binding affinities of both carboxylic- and phenolic-type groups, and smaller heterogeneity of carboxylic and phenolic-type groups. Amendment with CS or TS led to a decrease of acidic functional group contents and a slight increase of proton binding affinities of carboxylic- and phenolic-type groups of soil HAs and FAs. These effects were more evident in the HA and FA fractions from CS-amended soil than in those from TS-amended soil.

Lithospermic acid derivatives from Lithospermum erythrorhizon increased expression of serine palmitoyltransferase in human HaCaT cells.

PubMed

Thuong, Phuong Thien; Kang, Keon Wook; Kim, Jeong Kee; Seo, Dae Bang; Lee, Sang Jun; Kim, Sung Han; Oh, Won Keun

2009-03-15

A MeOH extract of the dry root of Lithospermum erythrorhizon showed strong increasing effect on serine palmitoyltransferase (SPT) in normal human keratinocyte cells (HaCaT cells). Bioassay-guided separation on this extract using repeated chromatography resulted in the isolation of lithospermic acid (1) and two derivative esters, 9''-methyl lithospermate (2) and 9'-methyl lithospermate (3). Compounds 1-3 significantly increased SPT expressions in the relative quantity (%) of SPT1 mRNA as well as SPT2 mRNA. These constituents also raised the level of SPT protein in HaCaT cells in a dose-dependent manner, with the increased level of SPT protein in HaCaT cells of 55%, 23%, and 81% at the concentration of 100 microg/ml, respectively. This finding suggests that lithospermic acid and its derivatives from L. erythrorhizon might improve the permeability barrier by stimulating the protein level of SPT.

Fractionation of fulvic acid by iron and aluminum oxides: influence on copper toxicity to Ceriodaphnia dubia

USGS Publications Warehouse

Smith, Kathleen S.; Ranville, James F.; Lesher, Emily K.; Diedrich, Daniel J.; McKnight, Diane M.; Sofield, Ruth M.

2014-01-01

This study examines the effect on aquatic copper toxicity of the chemical fractionation of fulvic acid (FA) that results from its association with iron and aluminum oxyhydroxide precipitates. Fractionated and unfractionated FAs obtained from streamwater and suspended sediment were utilized in acute Cu toxicity tests on ,i>Ceriodaphnia dubia. Toxicity test results with equal FA concentrations (6 mg FA/L) show that the fractionated dissolved FA was 3 times less effective at reducing Cu toxicity (EC50 13 ± 0.6 μg Cu/L) than were the unfractionated dissolved FAs (EC50 39 ± 0.4 and 41 ± 1.2 μg Cu/L). The fractionation is a consequence of preferential sorption of molecules having strong metal-binding (more aromatic) moieties to precipitating Fe- and Al-rich oxyhydroxides, causing the remaining dissolved FA to be depleted in these functional groups. As a result, there is more bioavailable dissolved Cu in the water and hence greater potential for Cu toxicity to aquatic organisms. In predicting Cu toxicity, biotic ligand models (BLMs) take into account dissolved organic carbon (DOC) concentration; however, unless DOC characteristics are accounted for, model predictions can underestimate acute Cu toxicity for water containing fractionated dissolved FA. This may have implications for water-quality criteria in systems containing Fe- and Al-rich sediment, and in mined and mineralized areas in particular. Optical measurements, such as specific ultraviolet absorbance at 254 nm (SUVA254), show promise for use as spectral indicators of DOC chemical fractionation and inferred increased Cu toxicity.

Effect of mineral surface properties (alumina, kaolinite) on the sorptive fractionation mechanisms of soil fulvic acids: Molecular-scale ESI-MS studies

NASA Astrophysics Data System (ADS)

Fleury, Guillaume; Del Nero, Mirella; Barillon, Rémi

2017-01-01

We addressed the effects of mineral surface properties (kaolinite versus Al-oxide) on the sorption-driven fractionation of a soil fulvic acid (FA) at acidic pH, mainly by means of ESI(-)-FTMS analysis of initial and supernatant solutions of FA sorption batch experiments. The MS data provided clear molecular-scale evidence of distinct mechanisms and molecular parameters controlling the FA fractionation upon its sorption on clay and oxide surfaces, respectively. Identification of sorbing and not-sorbing FA compounds in kaolinite-solution systems revealed a weak fractionation among members of sbnd CO2 series of aliphatics or not-condensed aromatics (NCAs) at pH 3.8, and almost no sorption of poorly-oxygenated polycyclic aromatic compounds (PACs) and NCAs. This first molecular-scale description of a FA fractionation in a clay-solution system suggests that H-bonding with low affinity sites (aluminol/silanol) on the basal planes of the clay particles is the main mechanism of sorption. Due to the predominance of such weak and poorly-selective mechanism, the sorption of aliphatic and NCA molecules bearing oxygenated functionalities was prevented at pH 5, due to dissolved Al competing successfully for their coordination. In contrast, a strong FA fractionation was observed onto alumina, with a preferential retention of PACs and highly-oxygenated aliphatics and NCAs. The major part of the poorly oxygenated aliphatics was left in solution. The sorption degree of NCAs and aliphatics was strongly correlated with molecular acidity. For PACs and poorly-oxygenated NCAs, the sorption was driven by reactions of surface ligand exchange (for the most oxygenated compounds) or by hydrophobic interactions (for the least oxygenated compounds).

Long-Term Fertilization Modifies the Structures of Soil Fulvic Acids and Their Binding Capability with Al

PubMed Central

Wu, Jun; Wu, Minjie; Li, Chunping; Yu, Guanghui

2014-01-01

The binding characteristics of organic ligands and minerals in fulvic acids (FAs) with Al are essential for understanding soil C sequestration, remain poorly understood. In this study, Fourier transform infrared (FTIR) spectroscopy combined with two-dimensional correlation spectroscopy (2DCOS) analysis was applied for the first time to explore the binding of Al with organic ligands and minerals in soil FAs. For these analyses, two contrasting treatments were selected from a long-term (i.e., 22-year) fertilization experiment: chemical (NPK) fertilization and swine manure (SM) fertilization. The results showed that the long-term application of organic and inorganic fertilizers to soils had little effect on the compositions of the fluorescent substances and organic ligands in the soil FAs. However, long-term SM fertilization increased the weathered Al and Si concentrations in the soil FAs compared with long-term chemical fertilization. Furthermore, organic ligands in the soil FAs were mainly bound with Al in the NPK treatment, whereas both organic ligands and minerals (Al-O-Si, Si-O) were bound with Al under the M fertilization conditions. Both transmission electron microscopy (TEM) images and X-ray diffraction spectra demonstrated that amorphous and short-range-ordered nanominerals were abundant in the soil FAs from the SM plot in contrast to the soil FAs from the NPK plot. This result illustrates the role nanominerals play in the preservation of soil FAs by during long-term organic fertilization. In summary, the combination of FTIR and 2D correlation spectroscopy is a promising approach for the characterization of the binding capability between soil FAs and Al, and a better understanding FA-Al binding capability will greatly contribute to global C cycling. PMID:25137372

[Apply fourier transform infrared spectra coupled with two-dimensional correlation analysis to study the evolution of humic acids during composting].

PubMed

Bu, Gui-jun; Yu, Jing; Di, Hui-hui; Luo, Shi-jia; Zhou, Da-zhai; Xiao, Qiang

2015-02-01

The composition and structure of humic acids formed during composting play an important influence on the quality and mature of compost. In order to explore the composition and evolution mechanism, municipal solid wastes were collected to compost and humic and fulvic acids were obtained from these composted municipal solid wastes. Furthermore, fourier transform infrared spectra and two-dimensional correlation analysis were applied to study the composition and transformation of humic and fulvic acids during composting. The results from fourier transform infrared spectra showed that, the composition of humic acids was complex, and several absorbance peaks were observed at 2917-2924, 2844-2852, 2549, 1662, 1622, 1566, 1454, 1398, 1351, 990-1063, 839 and 711 cm(-1). Compared to humic acids, the composition of fulvci acids was simple, and only three peaks were detected at 1725, 1637 and 990 cm(-1). The appearance of these peaks showed that both humic and fulvic acids comprised the benzene originated from lignin and the polysaccharide. In addition, humic acids comprised a large number of aliphatic and protein which were hardly detected in fulvic acids. Aliphatic, polysaccharide, protein and lignin all were degraded during composting, however, the order of degradation was different between humic and fulvci acids. The result from two-dimensional correlation analysis showed that, organic compounds in humic acids were degraded in the following sequence: aliphatic> protein> polysaccharide and lignin, while that in fulvic acids was as following: protein> polysaccharide and aliphatic. A large number of carboxyl, alcohols and ethers were formed during the degradation process, and the carboxyl was transformed into carbonates. It can be concluded that, fourier transform infrared spectra coupled with two-dimensional correlation analysis not only can analyze the function group composition of humic substances, but also can characterize effectively the degradation sequence of these

Impact of fulvic acids on bio-methanogenic treatment of municipal solid waste incineration leachate.

PubMed

Dang, Yan; Lei, Yuqing; Liu, Zhao; Xue, Yiting; Sun, Dezhi; Wang, Li-Ying; Holmes, Dawn E

2016-12-01

A considerable amount of leachate with high fulvic acid (FA) content is generated during the municipal solid waste (MSW) incineration process. This incineration leachate is usually processed by downstream bio-methanogenic treatment. However, few studies have examined the impact that these compounds have on methanogenesis and how they are degraded and transformed during the treatment process. In this study, a laboratory-scale expanded granular sludge bed (EGSB) reactor was operated with MSW incineration leachate containing various concentrations of FA (1500 mg/L to 8000 mg/L) provided as the influent. We found that FA degradation rates decreased from 86% to 72% when FA concentrations in the reactor were increased, and that molecular size, level of humification and aromatization of the residual FA macromolecules all increased after bio-methanogenic treatment. Increasing FA influent concentrations also inhibited growth of hydrogenotrophic methanogens from the genus Methanobacterium and syntrophic bacteria from the genus Syntrophomonas, which resulted in a decrease in methane production and a concomitant increase in CO 2 content in the biogas. Sequences most similar to species from the genus Anaerolinea went up as FA concentrations increased. Bacteria from this genus are capable of extracellular electron transfer and may be using FA as an electron acceptor for growth or as a shuttle for syntrophic exchange with other microorganisms in the reactor. In order to determine whether FA could serve as an electron shuttle to promote syntrophy in an anaerobic digester, co-cultures of Geobacter metallireducens and G. sulfurreducens were grown in the presence of FA from raw leachate or from residual bioreactor effluent. While raw FA stimulated electron transfer between these two bacteria, residual FA did not have any electron shuttling abilities, indicating that FA underwent a significant transformation during the bio-methanogenic treatment process. These results are

Antibiotic-containing hyaluronic acid gel as an antibacterial carrier: Usefulness of sponge and film-formed HA gel in deep infection.

PubMed

Matsuno, Hiroaki; Yudoh, Kazuo; Hashimoto, Masamichi; Himeda, Yasukazu; Miyoshi, Teruzo; Yoshida, Kaoru; Kano, Syogo

2006-03-01

We have developed a novel bioabsorbable antibacterial carrier using hyaluronic acid (HA) gel for prevention and treatment of orthopedic infections. In this study, we investigated the in vivo antibacterial effects of two forms of this new material, an HA gel sponge and an HA gel film. A titanium cylinder was inserted into the intramedullary cavity of each rabbit femur, along with an HA gel sponge or HA gel film containing antibiotics. The HA gel sponge contained gentamycin, vancomycin, tobramycin, or minomycin. The HA gel film contained gentamycin or vancomycin. After 0, 7, and 14 days, the rabbit bone marrow was collected, and the antibacterial activity of the HA gel was determined by agar diffusion test. As a control, we used Septocoll, a commercially available antibacterial carrier. Both the HA gel sponge and HA gel film exhibited antibacterial activity. The present results indicate that HA gel containing antibiotics is a clinically useful bioabsorbable antibacterial carrier. Copyright 2006 Orthopaedic Research Society.

Employing the cyclophosphate to accelerate the degradation of nano-hydroxyapatite/poly(amino acid) (n-HA/PAA) composite materials.

PubMed

Jing, Linjing; Chen, Li; Peng, Haitao; Ji, Mizhi; Xiong, Yi; Lv, Guoyu

2017-12-01

Owing to the good degradability and biocompatibility of polyphosphoesters (PPEs), the aim of the current study was to investigate a novel degradable composite of nano-hydroxyapatite/poly(amino acid) (n-HA/PAA) with cyclophosphate (CPE) via in situ melting polymerization to improve the degradation of n-HA/PAA. The structure of each composite was characterized via Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The degradation properties were studied in terms of the weight loss and pH in a phosphate-buffered saline (PBS) solution, while the surface morphology was examined using a scanning electron microscope-energy dispersive spectrometer (SEM-EDS) after soaking the surface in simulated body fluid (SBF). The cell proliferation, cell adhesion, and alkaline phosphatase (ALP) activity were used for the analysis of cytocompatibility. The weight loss results showed that the n-HA/PAA composite was 9.98 wt%, weighed after soaking in the PBS solution for 12 weeks, whereas the nano-hydroxyapatite/polyphosphoester-amino acid (n-HA/PPE-AA) composite was 46.94 wt%. The pH of the composites was in a suitable range between 6.64 to 7.06 and finally stabilized at 7.39. The SEM and EDS results revealed the formation of an apatite-like layer on the surface of the n-HA/PPE-AA composites after soaking in SBF for one week. The cell counting Kit 8 (CCK-8) assay of the cell culture in the leaching liquid of the n-HA/PPE-AA composites exhibited non-cytotoxicity and high-proliferation, and the cell adhesion showed the well spreading and normal phenotype extension of the cells on the n-HA/PPE-AA composites surface. Concurrently, the co-culture results of the composites and cells confirmed that the n-HA/PPE-AA composites exhibited a higher ALP activity. In summary, the results demonstrated that the n-HA/PPE-AA composites had a controllable degradation property, good bioactivity, and cytocompatibility.

Citric acid induces cell-cycle arrest and apoptosis of human immortalized keratinocyte cell line (HaCaT) via caspase- and mitochondrial-dependent signaling pathways.

PubMed

Ying, Tsung-Ho; Chen, Chia-Wei; Hsiao, Yu-Ping; Hung, Sung-Jen; Chung, Jing-Gung; Yang, Jen-Hung

2013-10-01

Citric acid is an alpha-hydroxyacid (AHA) widely used in cosmetic dermatology and skincare products. However, there is concern regarding its safety for the skin. In this study, we investigated the cytotoxic effects of citric acid on the human keratinocyte cell line HaCaT. HaCaT cells were treated with citric acid at 2.5-12.5 mM for different time periods. Cell-cycle arrest and apoptosis were investigated by 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining, flow cytometry, western blot and confocal microscopy. Citric acid not only inhibited proliferation of HaCaT cells in a dose-dependent manner, but also induced apoptosis and cell cycle-arrest at the G2/M phase (before 24 h) and S phase (after 24 h). Citric acid increased the level of Bcl-2-associated X protein (BAX) and reduced the levels of B-cell lymphoma-2 (BCL-2), B-cell lymphoma-extra large (BCL-XL) and activated caspase-9 and caspase-3, which subsequently induced apoptosis via caspase-dependent and caspase-independent pathways. Citric acid also activated death receptors and increased the levels of caspase-8, activated BH3 interacting-domain death agonist (BID) protein, Apoptosis-inducing factor (AIF), and Endonuclease G (EndoG). Therefore, citric acid induces apoptosis through the mitochondrial pathway in the human keratinocyte cell line HaCaT. The study results suggest that citric acid is cytotoxic to HaCaT cells via induction of apoptosis and cell-cycle arrest in vitro.

Natural and pyrogenic humic acids at goethite and natural oxide surfaces interacting with phosphate.

PubMed

Hiemstra, Tjisse; Mia, Shamim; Duhaut, Pierre-Benoît; Molleman, Bastiaan

2013-08-20

Fulvic and humic acids have a large variability in binding to metal (hydr) oxide surfaces and interact differently with oxyanions, as examined here experimentally. Pyrogenic humic acid has been included in our study since it will be released to the environment in the case of large-scale application of biochar, potentially creating Darks Earths or Terra Preta soils. A surface complexation approach has been developed that aims to describe the competitive behavior of natural organic matter (NOM) in soil as well as model systems. Modeling points unexpectedly to a strong change of the molecular conformation of humic acid (HA) with a predominant adsorption in the Stern layer domain at low NOM loading. In soil, mineral oxide surfaces remain efficiently loaded by mineral-protected organic carbon (OC), equivalent with a layer thickness of ≥ ~0.5 nm that represents at least 0.1-1.0% OC, while surface-associated OC may be even three times higher. In natural systems, surface complexation modeling should account for this pervasive NOM coverage. With our charge distribution model for NOM (NOM-CD), the pH-dependent oxyanion competition of the organo-mineral oxide fraction can be described. For pyrogenic HA, a more than 10-fold increase in dissolved phosphate is predicted at long-term applications of biochar or black carbon.

Activity-guided separation and characterization of new halocin HA3 from fermented broth of Haloferax larsenii HA3.

PubMed

Kumar, Vijay; Tiwari, Santosh Kumar

2017-05-01

Haloferax larsenii HA3 was able to grow optimally in HS medium containing 15% NaCl, at pH 7.2 and 42 °C in aerobic conditions. Strain HA3 was found to be round shape, Gram-negative, catalase-positive, sensitive to bile acid, and resistant to chloramphenicol, and could not utilize arginine. The lipid profile revealed the presence of glycerol diether moiety (GDEM) suggesting Haloarchaea characteristics. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that it was closely related to H. larsenii ZJ206. Interestingly, strain HA3 was found to produce halocin HA3 which was purified using ultrafiltration and chromatography. It was found to be stable up to 80 °C, pH 2.0-10.0, organic solvents, surfactants, and detergents tested. However, the activity of halocin HA3 was completely reduced in the presence of proteinase K and trypsin. It was found to be halocidal against H. larsenii HA10, rupturing cell boundary and leading to cell death. The molecular weight of halocin HA3 was found to be ~13 kDa and MALDI-TOF MS/MS analysis suggested no homology with known halocins. The N-terminal ten amino-acid residues, NH 2 MNLGIILETN-COOH, suggested a new/novel halocin. These properties of halocin HA3 may be applicable for control of Haloarchaea in environments and salted foods.

Homology modeling study toward identifying structural properties in the HA2 B-loop that would influence the HA1 receptor-binding site.

PubMed

Cueno, Marni E; Imai, Kenichi; Shimizu, Kazufumi; Ochiai, Kuniyasu

2013-07-01

Influenza hemagglutinin (HA) consists of a fibrous globular stem (HA2) inserted into the viral membrane supporting a globular head (HA1). HA1 receptor-binding has been hypothesized to be structurally correlated to the HA2 B-loop, however, this was never fully understood. Here, we elucidated the structural relationship between the HA2 B-loop and the HA1 receptor-binding site (RBS). Throughout this study, we analyzed 2486 H1N1 HA homology models obtained from human, swine and avian strains during 1976-2012. Quality of all homology models were verified before further analyses. We established that amino acid residue 882 is putatively strain-conserved and differs in the human (K882), swine (H882) and avian (N882) strains. Moreover, we observed that the amino acid at residue 882 and, similarly, its orientation has the potential to influence the HA1 RBS diameter measurements which we hypothesize may consequentially affect influenza H1N1 viral infectivity, immune escape, transmissibility, and evolution. Copyright © 2013 Elsevier Inc. All rights reserved.

[Fluorescence spectroscopic characteristics of fulvic acid from the long-term located fertilization in black soil].

PubMed

Li, Yan-Ping; Wei, Dan; Zhou, Bao-Ku; Zhao, Yue; Zhang, Xi-Lin; Wei, Zi-Min; Li, Shu-Ling

2011-10-01

In order to investigate the effect of long-term located fertilization on soil fulvic acid (FA), in this study, four soil samples were taken from black soil with long-term located fertilization (about 30 year) in Harbin, Heilongjiang province. The fertilization treatments included control (CK), N, P and K fertilization (NPK), horse manure (OM), combination of organic manure and chemical fertilizations (MNPK). Soil FA was extracted from the samples and purified. The excitation, emission, synchronous, and three-dimensional-excitation emission matrix fluorescence spectroscopy (3DEEM) characteristics of the FA were determined. The excitation, emission and synchronous scan spectra all indicated that the main peaks of FA in the NPK treatment exhibited a significantly blue shift compared with CK, while those of MNPK, OM treatment caused a red shift to some extent. 3DEEM spectra of FA in all treatments exhibited four peaks (peak a, peak b, peak c, and peak d), compared with FA in CK, the wavelengths shift tendency of peak a, peak b, and peak c of FA 3DEEM in NPK, MNPK and OM treatments were similar to that of traditional spectra in FA. In order to provide quantitative information of FA humification degree in different treatments, we investigated the fluorescence index f450/500 (FI), area integration (A370-600 nm, A1 370-412 nm, A4 538-600 nm). Compared with CK, the f450/500, ratio of A1/A in NPK and A4/A in MNPK treatment increased by 4.62%, 6.12%, 7.22%, respectively. However, the f450/500, the ratio of A1/A in MNPK and A4/A in NPK treatment decreased by 3.86%, 15.31%, and 7.22% respectively. This indicated that NPK application gave a lower degree of FA humification, and combination of organic manure and chemical fertilizations would lead to a greater degree of FA aromatization in black soil with long-term located fertilization than CK.

Facilitated Bioaccumulation of Perfluorooctanesulfonate in Common Carp (Cyprinus carpio) by Graphene Oxide and Remission Mechanism of Fulvic Acid.

PubMed

Qiang, Liwen; Chen, Meng; Zhu, Lingyan; Wu, Wei; Wang, Qiang

2016-11-01

As one of the most popular carbon-based nanomaterials, graphene oxide (GO) has the potential to be released in aquatic environment and interact with some coexistent organic pollutants, such as perfluorooctanesulfonate (PFOS), which is an emerging persistent organic pollutant. In this study, the adsorption of PFOS on GO in the presence of fulvic acid (FA), the impacts of GO and FA on PFOS toxicokinetics in carp (Cyprinus carpio), and in vitro digestion behaviors were examined. The results indicated that PFOS could be strongly adsorbed on GO with a Freundlich affinity coefficient K F of 580 ± 205 (mg/g)/(mg/L) n , while the adsorption was suppressed by FA due to competitive adsorption. GO significantly enhanced the bioaccumulation of PFOS in blood, kidney, liver, gill, intestine, and muscle of carp, and the corresponding bioaccumulation factor (BAF) was in the range of 2026-53513 L/kg. The enhancement was greatest for liver and intestine, which was 10.3 and 9.33 times of that without GO, respectively. In vivo toxicokinetic and in vitro digestion-absorption experiments indicated that GO could carry PFOS to penetrate the intestine cells. There herein, PFOS absorption, especially via intestine, and the uptake rate coefficient (k u ) were greatly enhanced, leading to distinctly promoted bioaccumulation of PFOS in fish. However, FA could facilitate the flocculation of GO in the intestine and also accelerate excretion of GO-PFOS complex. Thus, in the presence of FA, PFOS absorption was reduced and the promotion effect of GO on PFOS accumulation was remitted.

Porphyra-334, a mycosporine-like amino acid, attenuates UV-induced apoptosis in HaCaT cells.

PubMed

Suh, Sung-Suk; Oh, Se Kyung; Lee, Sung Gu; Kim, Il-Chan; Kim, Sanghee

2017-06-27

The main aim of the current research was to study the effect of porphyra-334, one of mycosporine-like amino acids (MAAs), well known as UV-absorbing compounds, on UVinduced apoptosis in human immortalized keratinocyte (HaCaT) cells. Due to their UV-screening capacity and ability to prevent UV-induced DNA damage, MAAs have recently attracted considerable attention in both industry and research in pharmacology. Herein, human HaCaT cells were used to determine the biological activities of porphyra- 334 by various in vitro assays, including proliferation, apoptosis and Western blot assays. The proliferation rate of UV-irradiated HaCaT cells was significantly decreased compared to the control group. Pretreatment with porphyra- 334 markedly attenuated the inhibitory effect of UV and induced a dramatic decrease in the apoptotic rate. Expression of active caspase-3 protein was increased in response to UV irradiation, while caspase-3 levels were similar between cells treated with porphyra-334 and the non-irradiated control group. Taken together, our data suggest that porphyra-334 inhibits UV-induced apoptosis in HaCaT cells through attenuation of the caspase pathway.

Posttranslational modification of Ha-ras p21 by farnesyl versus geranylgeranyl isoprenoids is determined by the COOH-terminal amino acid.

PubMed Central

Kinsella, B T; Erdman, R A; Maltese, W A

1991-01-01

ras proteins undergo posttranslational modification by a 15-carbon farnesyl isoprenoid at a cysteine within a defined COOH-terminal amino acid motif; i.e., Cys-Ali-Ali-Ser/Met (where Ali represents an aliphatic residue). In other low molecular mass GTP-binding proteins, cysteines are modified by 20-carbon geranylgeranyl groups within a Cys-Ali-Ali-Leu motif. We changed the terminal Ser-189 of Ha-ras p21 to Leu-189 by site-directed mutagenesis and found that the protein was modified by [3H]geranylgeranyl instead of [3H]farnesyl in an in vitro assay. Gel-permeation chromatography of [3H]mevalonate-labeled hydrocarbons released from immunoprecipitated ras proteins overexpressed in COS cells indicated that Ha-ras p21(Leu-189) was also a substrate for 20-carbon isoprenyl modification in vivo. Additional steps in Ha-ras p21 processing, normally initiated by farnesylation, appear to be supported by geranylgeranylation, based on metabolic labeling of Ha-ras p21(Leu-189) with [3H]palmitate and its subcellular localization in a particulate fraction from COS cells. These observations indicate that the amino acid occupying the terminal position (Xaa) in the Cys-Ali-Ali-Xaa motif constitutes a key structural feature by which Ha-ras p21 and other proteins with ras-like COOH-terminal isoprenylation sites are distinguished as substrates for farnesyl- or geranylgeranyltransferases. Images PMID:1924354

Clinical comparison of oral administration and viscosupplementation of hyaluronic acid (HA) in early knee osteoarthritis.

PubMed

Ricci, M; Micheloni, G M; Berti, M; Perusi, F; Sambugaro, E; Vecchini, E; Magnan, B

2017-04-01

Osteoarthritis (OA) is a progressive, chronic and degenerative joint disease characterized by a loss of articular cartilage. Treatment of OA is largely palliative based on nonsteroidal anti-inflammatory drugs, opioids and injections of steroids. Regarding conservative treatment, intra-articular injections of hyaluronic acid (HA) can play a role in early symptomatic knee OA. Between August 2015 and September 2015, sixty patients (32 males and 28 females) between 40 and 70 years old were randomly allocated into two groups: Half were treated with three weekly intra-articular injections of hyaluronic acid 1.6 % (group A), while the others were treated with Syalox 300 Plus ® (hyaluronic acid 300 mg + Boswellia serrata extract 100 mg) 1 tab/die for 20 days and afterward Syalox 150 ® (hyaluronic acid 150 mg) 1 tab/die for other 20 days (group B). All patients were evaluated clinically with American Knee Society Score (AKSS) and visual analogue scale (VAS) for the pain before the treatment and after 3 months. AKSS of the patients in both groups was significantly increased by the treatment, and VAS score was significantly reduced. In both groups, two subgroups were created with patients older than 60 years and patients younger than 60 years. Better results are reported in younger patients of group A and older subjects in group B. Despite several limitations, the results of the study have shown that HA injection and oral administration may have beneficial therapeutic effects on patients with early osteoarthritis. Different outcomes in younger and older subject suggested a combined therapy first with local infiltrations and then with oral composition.

Fluorescence spectroscopy reveals accompanying occurrence of ammonium with fulvic acid-like organic matter in a fluvio-lacustrine aquifer of Jianhan Plain.

PubMed

Huang, Shuangbing; Wang, Yanxin; Ma, Teng; Wang, Yanyan; Zhao, Long

2016-05-01

This study is the first to investigate the simultaneous presence of NH4 (+) and fluorescent organic matter components (FOCs) from a fluvio-lacustrine aquifer in Central Jianghan Plain. Sediment, groundwater, and surface water samples were collected for the sediment organic matter extraction, 3D fluorescence spectroscopy characterization, and/or hydrochemical analysis. NH4 (+) and dissolved organic carbon was ubiquitous in the groundwater. The fluorescence spectroscopy revealed good relationships between NH4 (+) and fulvic acid-like components (FALCs) in the groundwater and sediment-extracted organic matter (SEOM) solutions. NH4 (+) also exhibited significant positive correlation with protein-like component (PLC) (p < 0.001), with the stronger in the SEOM solutions than that in groundwater. Comparisons of spectroscopic indices [e.g., humification index (HIX), biological index (BIX), spectra slope (S275-295), and specific UV absorbance (SUVA254)] between the groundwater and SEOM solutions revealed more labile properties of SEOM. This result indicates that the decreasing NH4 (+)-FOCs correlations of groundwater relative to sediments may be attributed to microbial degradation. Factor analysis identifies important factors that cause NH4 (+) occurrence in the groundwater. The accompanying increase of FALC (C1) and NH4-N with the mole concentration of the normalized HCO3 (-)/(Ca(2+)+Mg(2+)) and [H(+)] suggests that couple effects of various biodegradations simultaneously occur in the aquifer, promoting the occurrence of NH4-DOMs.

Characterization and diagenesis of strong-acid carboxyl groups in humic substances

USGS Publications Warehouse

Leenheer, J.A.; Wershaw, R. L.; Brown, G.K.; Reddy, M.M.

2003-01-01

A small fraction of carboxylic acid functional groups in humic substances are exceptionally acidic with pKa values as low as 0.5. A review of acid-group theory eliminated most models and explanations for these exceptionally acidic carboxyl groups. These acidic carboxyl groups in Suwannee River fulvic acid were enriched by a 2-stage fractionation process and the fractions were characterized by elemental, molecular-weight, and titrimetric analyses, and by infrared and 13C- and 1H-nuclear magnetic resonance spectrometry. An average structural model of the most acidic fraction derived from the characterization data indicated a high density of carboxyl groups clustered on oxygen-heterocycle alicyclic rings. Intramolecular H-bonding between adjacent carboxyl groups in these ring structures enhanced stabilization of the carboxylate anion which results in low pKa1 values. The standard, tetrahydrofuran tetracarboxylic acid, was shown to have similar acidity characteristics to the highly acidic fulvic acid fraction. The end products of 3 known diagenetic pathways for the formation of humic substances were shown to result in carboxyl groups clustered on oxygen-heterocycle alicyclic rings.

Isolation and characterization of Chinese standard fulvic acid sub-fractions separated from forest soil by stepwise elution with pyrophosphate buffer.

PubMed

Bai, Yingchen; Wu, Fengchang; Xing, Baoshan; Meng, Wei; Shi, Guolan; Ma, Yan; Giesy, John P

2015-03-04

XAD-8 adsorption technique coupled with stepwise elution using pyrophosphate buffers with initial pH values of 3, 5, 7, 9, and 13 was developed to isolate Chinese standard fulvic acid (FA) and then separated the FA into five sub-fractions: FApH3, FApH5, FApH7, FApH9 and FApH13, respectively. Mass percentages of FApH3-FApH13 decreased from 42% to 2.5%, and the recovery ratios ranged from 99.0% to 99.5%. Earlier eluting sub-fractions contained greater proportions of carboxylic groups with greater polarity and molecular mass, and later eluting sub-fractions had greater phenolic and aliphatic content. Protein-like components, as well as amorphous and crystalline poly(methylene)-containing components were enriched using neutral and basic buffers. Three main mechanisms likely affect stepwise elution of humic components from XAD-8 resin with pyrophosphate buffers including: 1) the carboxylic-rich sub-fractions are deprotonated at lower pH values and eluted earlier, while phenolic-rich sub-fractions are deprotonated at greater pH values and eluted later. 2) protein or protein-like components can be desorbed and eluted by use of stepwise elution as progressively greater pH values exceed their isoelectric points. 3) size exclusion affects elution of FA sub-fractions. Successful isolation of FA sub-fractions will benefit exploration of the origin, structure, evolution and the investigation of interactions with environmental contaminants.

Isolation and Characterization of Chinese Standard Fulvic Acid Sub-fractions Separated from Forest Soil by Stepwise Elution with Pyrophosphate Buffer

PubMed Central

Bai, Yingchen; Wu, Fengchang; Xing, Baoshan; Meng, Wei; Shi, Guolan; Ma, Yan; Giesy, John P.

2015-01-01

XAD-8 adsorption technique coupled with stepwise elution using pyrophosphate buffers with initial pH values of 3, 5, 7, 9, and 13 was developed to isolate Chinese standard fulvic acid (FA) and then separated the FA into five sub-fractions: FApH3, FApH5, FApH7, FApH9 and FApH13, respectively. Mass percentages of FApH3-FApH13 decreased from 42% to 2.5%, and the recovery ratios ranged from 99.0% to 99.5%. Earlier eluting sub-fractions contained greater proportions of carboxylic groups with greater polarity and molecular mass, and later eluting sub-fractions had greater phenolic and aliphatic content. Protein-like components, as well as amorphous and crystalline poly(methylene)-containing components were enriched using neutral and basic buffers. Three main mechanisms likely affect stepwise elution of humic components from XAD-8 resin with pyrophosphate buffers including: 1) the carboxylic-rich sub-fractions are deprotonated at lower pH values and eluted earlier, while phenolic-rich sub-fractions are deprotonated at greater pH values and eluted later. 2) protein or protein-like components can be desorbed and eluted by use of stepwise elution as progressively greater pH values exceed their isoelectric points. 3) size exclusion affects elution of FA sub-fractions. Successful isolation of FA sub-fractions will benefit exploration of the origin, structure, evolution and the investigation of interactions with environmental contaminants. PMID:25735451

78 FR 46265 - Complex Polymeric Polyhydroxy Acids; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-31

... number of analyses to determine the risks from aggregate exposure to pesticide residues. First, EPA... agricultural soils. Its major components are humic acid, fulvic acid, and tannins, and their relative...

Hyaluronic acid doped-poly(3,4-ethylenedioxythiophene)/chitosan/gelatin (PEDOT-HA/Cs/Gel) porous conductive scaffold for nerve regeneration.

PubMed

Wang, Shuping; Guan, Shui; Zhu, Zhibo; Li, Wenfang; Liu, Tianqing; Ma, Xuehu

2017-02-01

Conducting polymer, as a "smart" biomaterial, has been increasingly used to construct tissue engineered scaffold for nerve tissue regeneration. In this study, a novel porous conductive scaffold was prepared by incorporating conductive hyaluronic acid (HA) doped-poly(3,4-ethylenedioxythiophene) (PEDOT-HA) nanoparticles into a chitosan/gelatin (Cs/Gel) matrix. The physicochemical characteristics of Cs/Gel scaffold with 0-10wt% PEDOT-HA were analyzed and the results indicated that the incorporation of PEDOT-HA into scaffold increased the electrical and mechanical properties while decreasing the porosity and water absorption. Moreover, in vitro biodegradation of scaffold displayed a declining trend with the PEDOT-HA content increased. About the biocompatibility of conductive scaffold, neuron-like rat phaeochromocytoma (PC12) cells were cultured in scaffold to evaluate cell adhesion and growth. 8% PEDOT-HA/Cs/Gel scaffold had a higher cell adhesive efficiency and cell viability than the other conductive scaffolds. Furthermore, cells in the scaffold with 8wt% PEDOT-HA expressed higher synapse growth gene of GAP43 and SYP compared with Cs/Gel control group. These results suggest that 8%PEDOT-HA/Cs/Gel scaffold is an attractive cell culture conductive substrate which could support cell adhesion, survival, proliferation, and synapse growth for the application in nerve tissue regeneration. Copyright © 2016 Elsevier B.V. All rights reserved.

Posttranslational modification of Ha-ras p21 by farnesyl versus geranylgeranyl isoprenoids is determined by the COOH-terminal amino acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinsella, B.T.; Erdman, R.A.; Maltese, W.A.

ras proteins undergo posttranslational modification by a 15-carbon farnesyl isoprenoid at a cysteine within a defined COOH-terminal amino acid motif; i.e., Cys-Ali-Ali-Ser/Met (where Ali represents an aliphatic residue). In other low molecular mass GTP-binding proteins, cysteines are modified by 20-carbon geranylgeranyl groups within a Cys-Ali-Ali-Leu motif. The authors changed the terminal Ser-189 of Ha-ras p21 to Leu-189 by site-directed mutagenesis and found that the protein was modified by ({sup 3}H)geranylgeranyl instead of ({sup 3}H)farnesyl in an in vitro assay. Gel-permeation chromatography of ({sup 3}H)mevalonate-labeled hydrocarbons released from immunoprecipitated ras proteins overexpressed in COS cells indicated that Ha-ras p21 (Leu-189) wasmore » also a substrate for 20-carbon isoprenyl modification in vivo. Additional steps in Ha-ras p21 processing, normally initiated by farnesylation, appear to be supported by geranylgeranylation, based on metabolic labeling of Ha-ras p21 (Leu-189) with ({sup 3}H) palmitate and its subcellular localization in a particulate fraction from COS cells. These observations indicate that the amino acid occupying the terminal position (Xaa) in the Cys-Ali-Ali-Xaa motif constitutes a key structural feature by which Ha-ras p21 and other proteins with ras-like COOH-terminal isoprenylation sites are distinguished as substrates for farnesyl- or geranylgeranyltransferases.« less

Total organic carbon and humus fractions in restored soils from limestone quarries in semiarid climate, SE Spain

NASA Astrophysics Data System (ADS)

Luna Ramos, Lourdes; Miralles Mellado, Isabel; Ángel Domene Ruiz, Miguel; Solé Benet, Albert

2016-04-01

Mining activities generate erosion and loss of plant cover and soil organic matter (SOM), especially in arid and semiarid Mediterranean regions. A precondition for ecosystem restoration in such highly disturbed areas is the development of functional soils with sufficient organic matter. But the SOM quality is also important to long-term C stabilization. The resistance to biodegradation of recalcitrant organic matter fractions has been reported to depend on some intrinsic structural factors of humic acid substances and formation of amorphous organo-mineral recalcitrant complexes. In an experimental soil restoration in limestone quarries in the Sierra de Gádor (Almería), SE Spain, several combinations of organic amendments (sewage sludge and compost from domestic organic waste) and mulches (gravel and woodchip) were added in experimental plots using a factorial design. In each plot, 75 native plants (Anthyllis cytisoides, A. terniflora and Macrochloa tenacissima) were planted and five years after the start of the experiment total organic carbon (TOC), physico-chemical soil properties and organic C fractions (particulate organic matter, H3PO4-fulvic fraction, fulvic acids (FA), humic acids (HA) and humin) were analyzed. We observed significant differences between treatments related to the TOC content and the HA/FA ratio. Compost amendments increased the TOC, HA content and HA/FA ratio, even higher than in natural undisturbed soils, indicating an effective clay humus-complex pointing to progressively increasing organic matter quality. Soils with sewage sludge showed the lowest TOC and HA/FA ratio and accumulated a lower HA proportion indicating poorer organic matter quality and comparatively lower resilience than in natural soils and soils amended with compost.

Increase in gap-junctional intercellular communications (GJIC) of normal human dermal fibroblasts (NHDF) on surfaces coated with high-molecular-weight hyaluronic acid (HMW HA).

PubMed

Park, Jeong Ung; Tsuchiya, Toshie

2002-06-15

Normal human dermal fibroblast (NHDF) cells were used to detect differences in gap-junctional intercellular communication (GJIC) by hyaluronic acid (HA), a linear polymer built from repeating disaccharide units that consist of N-acetyl-D-glucosamine (GlcNa) and D-glucuronic acid (GlcA) linked by a beta 1-4 glycosidic bond. The NHDF cells were cultured with different molecular weights (MW) of HA for 4 days. The rates of cell attachment in dishes coated with high-molecular-weight (HMW; 310 kDa or 800 kDa) HA at 2 mg/dish were significantly reduced at an early time point compared with low-molecular-weight (LMW; 4.8 kDa or 48 kDa) HA with the same coating amounts. HA-coated surfaces were observed by atomic force microscopy (AFM) under air and showed that HA molecules ran parallel in the dish coated with LMW HA and had an aggregated island structure in the dish coated with HMW HA surfaces. The cell functions of GJIC were assayed by a scrape-loading dye transfer (SLDT) method using a dye solution of Lucifer yellow. Promotion of the dye transfer was clearly obtained in the cell monolayer grown on the surface coated with HMW HA. These results suggest that HMW HA promotes the function of GJIC in NHDF cells. In contrast, when HMW HA was added to the monolayer of NHDF cells, the functions of GJIC clearly were lowered in comparison with the cells grown in the control dish or with those grown on the surface of HMW HA. Therefore it is concluded that the MW size of HA and its application method are important factors for generating biocompatible tissue-engineered products because of the manner in which the GJIC participates in cell differentiation and cell growth rate. Copyright 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 541-547, 2002

Variation of physicochemical properties of drinking water treatment residuals and Phoslock(®) induced by fulvic acid adsorption: Implication for lake restoration.

PubMed

Wang, Changhui; Jiang, He-Long; Xu, Huacheng; Yin, Hongbin

2016-01-01

The use of phosphorus (P) inactivating agents to reduce internal P loading from sediment for lake restoration has attracted increasing attention. Reasonably, the physicochemical properties of P inactivating agents may vary with the interference of various environmental factors, leading to the change of control effectiveness and risks. In this study, the effect of fulvic acid (FA) adsorption on the properties of two agents, drinking water treatment residuals (DWTRs) and Phoslock®, was investigated. The results showed that after adsorption, there was little change for the main structures of DWTRs and Phoslock®, but the thermostability of Phoslock®, as well as the particle size and settleability of the two agents decreased. The specific surface area and pore volume of DWTRs also decreased, while those of Phoslock® increased. Further analysis indicated that aluminum and iron in DWTRs were stable during FA adsorption, but a substantial increase of lanthanum release from Phoslock® was observed, in particular at first (P < 0.01). Moreover, the P immobilization capability of DWTRs had little change after FA adsorption, while the capability of Phoslock® after FA adsorption decreased in solutions (P < 0.001) and sediments (P < 0.1); interestingly, from the view of engineering application, the performance of Phoslock® was not substantially affected. Overall, each P inactivating agent had its own particular responses of the physicochemical properties to environment factors, and detailed investigations on the applicability of each agent were essential before practical application.

Adsorption and fractionation of a muck fulvic acid on kaolinite and goethite at pH 3.7,6, and 8

USGS Publications Warehouse

Namjesnik-Dejanovic, K.; Maurice, P.A.; Aiken, G.R.; Cabaniss, S.; Chin, Y.-P.; Pullin, M.J.

2000-01-01

Molecular weight (MW) of humic materials is a key factor controlling proton and metal binding and organic pollutant partitioning. Several studies have suggested preferential adsorption of higher MW, more aromatic moieties to mineral surfaces; quantification of such processes is fundamental to development of predictive models. We used high pressure size exclusion chromatography (HPSEC) to quantify MW changes upon adsorption of a muck fulvic acid (MFA) extracted from a peat deposit to kaolinite and goethite, at pH 3.7,6, and 8 at 22 ??C, I = 0.01 (NaC1), 24-h reaction time. MFA adsorption affinity was greater for goethite than for kaolinite. At concentrations less than the adsorption maximum (A(max)) for both adsorbents, the weight-average MW (M(w)) of MFA remaining in solution decreased by as much as several hundred Daltons relative to control samples, indicating preferential adsorption of the higher MW components. At concentrations more than A(max), M(w) of MFA in solution did not change appreciably. Although total adsorption decreased significantly as pH increased, fractionation as measured by change in M(w) remained similar, perhaps indicating greater selectivity for higher MW components at higher pH. Absorptivities at ?? = 280 nm normalized to mg C L-1 (??) suggested preferential adsorption of more aromatic moieties to kaolinite. ?? could not be used for goethite-reacted samples because high Fe concentrations in the aqueous phase brought about by goethite dissolution interfered with the spectroscopic analysis. Preliminary kinetic experiments suggested that smaller molecules adsorbed first and were replaced by larger molecules whose adsorption was thermodynamically favored.

Humic substances and trace metals associated with Fe and Al oxides deposited in an acidic mountain stream

USGS Publications Warehouse

McKnight, Diane M.; Wershaw, R. L.; Bencala, K.E.; Zellweger, G.W.; Feder, G.L.

1992-01-01

Hydrous iron and aluminum oxides are deposited on the streambed in the confluence of the Snake River and Deer Creek, two streams in the Colorado Rocky Mountains. The Snake River is acidic and has high concentrations of dissolved Fe and Al. These metals precipitate at the confluence with the pristine, neutral pH, Deer Creek because of the greater pH (4.5-6.0) in the confluence. The composition of the deposited oxides changes consistently with distance downstream, with the most upstream oxide samples having the greatest Fe and organic carbon content. Fulvic acid accounts for most of the organic content of the oxides. Results indicate that streambed oxides in the confluence are not saturated with respect to their capacity to sorb dissolved humic substances from streamwater. The contents of several trace metals (Mn, Zn, Cu, Pb, Ni and Co) also decrease with distance downstream and are correlated with both the Fe and organic carbon contents. Strong metal-binding sites associated with the sorbed fulvic acid are more than sufficient to account for the trace metal content of the oxides. Complexation of trace metals by sorbed fulvic acid may explain the observed downstream decrease in trace metal content.

The effect of the type of HA on the degradation of PLGA/HA composites.

PubMed

Naik, Ashutosh; Shepherd, David V; Shepherd, Jennifer H; Best, Serena M; Cameron, Ruth E

2017-01-01

The aim of this study is to explore the importance of the potentially competing effects of buffering effects of the calcium phosphate filler and particle-mediated water sorption on the degradation products of poly(d,l lactide-co-glycolide (50:50))(PLGA)/hydroxyapatite(HA) composites. Further the influence of type of HA on the mechanical properties of the composites was investigated. Phase pure HA was synthesised via a reaction between aqueous solutions of calcium hydroxide and orthophosphoric acid. The powder produced was either used as produced (uncalcined) or calcined in air or calcined in a humidified argon atmosphere. An in-vitro degradation study was carried out in phosphate buffered saline (PBS). The results obtained indicated that the degradation rate of the composite might be better understood if both the buffering effects and the rate of water sorption by the composites are considered. Copyright © 2016 Elsevier B.V. All rights reserved.

Crystal structure of the HA3 subcomponent of Clostridium botulinum type C progenitor toxin.

PubMed

Nakamura, Toshio; Kotani, Mao; Tonozuka, Takashi; Ide, Azusa; Oguma, Keiji; Nishikawa, Atsushi

2009-01-30

The Clostridium botulinum type C 16S progenitor toxin contains a neurotoxin and several nontoxic components, designated nontoxic nonhemagglutinin (HA), HA1 (HA-33), HA2 (HA-17), HA3a (HA-22-23), and HA3b (HA-53). The HA3b subcomponent seems to play an important role cooperatively with HA1 in the internalization of the toxin by gastrointestinal epithelial cells via binding of these subcomponents to specific oligosaccharides. In this study, we investigated the sugar-binding specificity of the HA3b subcomponent using recombinant protein fused to glutathione S-transferase and determined the three-dimensional structure of the HA3a-HA3b complex based on X-ray crystallography. The crystal structure was determined at a resolution of 2.6 A. HA3b contains three domains, domains I to III, and the structure of domain I resembles HA3a. In crystal packing, three HA3a-HA3b molecules are assembled to form a three-leaved propeller-like structure. The three HA3b domain I and three HA3a alternate, forming a trimer of dimers. In a database search, no proteins with high structural homology to any of the domains (Z score >10) were found. Especially, HA3a and HA3b domain I, mainly composed of beta-sheets, reveal a unique fold. In binding assays, HA3b bound sialic acid with high affinity, but did not bind galactose, N-acetylgalactosamine, or N-acetylglucosamine. The electron density of liganded N-acetylneuraminic acid was determined by crystal soaking. In the sugar-complex structure, the N-acetylneuraminic acid-binding site was located in the cleft formed between domains II and III of HA3b. This report provides the first determination of the three-dimensional structure of the HA3a-HA3b complex and its sialic acid binding site. Our results will provide useful information for elucidating the mechanism of assembly of the C16S toxin and for understanding the interactions with oligosaccharides on epithelial cells and internalization of the botulinum toxin complex.

Use of thermal analysis coupled with differential scanning calorimetry, quadrupole mass spectrometry and infrared spectroscopy (TG-DSC-QMS-FTIR) to monitor chemical properties and thermal stability of fulvic and humic acids.

PubMed

Boguta, Patrycja; Sokołowska, Zofia; Skic, Kamil

2017-01-01

Thermogravimetry-coupled with differential scanning calorimetry, quadrupole mass spectrometry, and Fourier-transform infrared spectroscopy (TG-DSC-QMS-FTIR)-was applied to monitor the thermal stability (in an N2 pyrolytic atmosphere) and chemical properties of natural polymers, fulvic (FA) and humic acids (HA), isolated from chemically different soils. Three temperature ranges, R1, 40-220°C; R2, 220-430°C; and R3, 430-650°C, were distinguished from the DSC data, related to the main thermal processes of different structures (including transformations without weight loss). Weight loss (ΔM) estimated from TG curves at the above temperature intervals revealed distinct differences within the samples in the content of physically adsorbed water (at R1), volatile and labile functional groups (at R2) as well as recalcitrant and refractory structures (at R3). QMS and FTIR modules enabled the chemical identification (by masses and by functional groups, respectively) of gaseous species evolved during thermal decomposition at R1, R2 and R3. Variability in shape, area and temperature of TG, DSC, QMS and FTIR peaks revealed differences in thermal stability and chemical structure of the samples between the FAs and HAs fractions of different origin. The statistical analysis showed that the parameters calculated from QMS (areas of m/z = 16, 17, 18, 44), DSC (MaxDSC) and TG (ΔM) at R1, R2 and R3 correlated with selected chemical properties of the samples, such as N, O and COOH content as well as E2/E6 and E2/E4 indexes. This indicated a high potential for the coupled method to monitor the chemical changes of humic substances. A new humification parameter, HTD, based on simple calculations of weight loss at specific temperature intervals proved to be a good alternative to indexes obtained from other methods. The above findings showed that the TG-DSC-QMS-FTIR coupled technique can represent a useful tool for the comprehensive assessment of FAs and HAs properties related to their

Use of thermal analysis coupled with differential scanning calorimetry, quadrupole mass spectrometry and infrared spectroscopy (TG-DSC-QMS-FTIR) to monitor chemical properties and thermal stability of fulvic and humic acids

PubMed Central

Sokołowska, Zofia; Skic, Kamil

2017-01-01

Thermogravimetry–coupled with differential scanning calorimetry, quadrupole mass spectrometry, and Fourier-transform infrared spectroscopy (TG-DSC-QMS-FTIR)–was applied to monitor the thermal stability (in an N2 pyrolytic atmosphere) and chemical properties of natural polymers, fulvic (FA) and humic acids (HA), isolated from chemically different soils. Three temperature ranges, R1, 40–220°C; R2, 220–430°C; and R3, 430–650°C, were distinguished from the DSC data, related to the main thermal processes of different structures (including transformations without weight loss). Weight loss (ΔM) estimated from TG curves at the above temperature intervals revealed distinct differences within the samples in the content of physically adsorbed water (at R1), volatile and labile functional groups (at R2) as well as recalcitrant and refractory structures (at R3). QMS and FTIR modules enabled the chemical identification (by masses and by functional groups, respectively) of gaseous species evolved during thermal decomposition at R1, R2 and R3. Variability in shape, area and temperature of TG, DSC, QMS and FTIR peaks revealed differences in thermal stability and chemical structure of the samples between the FAs and HAs fractions of different origin. The statistical analysis showed that the parameters calculated from QMS (areas of m/z = 16, 17, 18, 44), DSC (MaxDSC) and TG (ΔM) at R1, R2 and R3 correlated with selected chemical properties of the samples, such as N, O and COOH content as well as E2/E6 and E2/E4 indexes. This indicated a high potential for the coupled method to monitor the chemical changes of humic substances. A new humification parameter, HTD, based on simple calculations of weight loss at specific temperature intervals proved to be a good alternative to indexes obtained from other methods. The above findings showed that the TG-DSC-QMS-FTIR coupled technique can represent a useful tool for the comprehensive assessment of FAs and HAs properties related

Quantitative genetics of circulating Hyaluronic Acid (HA) and its correlation with hand osteoarthritis and obesity-related phenotypes in a community-based sample.

PubMed

Prakash, Jai; Gabdulina, Gulzhan; Trofimov, Svetlana; Livshits, Gregory

2017-09-01

One of the potential molecular biomarkers of osteoarthritis (OA) is hyaluronic acid (HA). HA levels may be related to the severity and progression of OA. However, little is known about the contribution of major risk factors for osteoarthritis, e.g. obesity-related phenotypes and genetics to HA variation. To clarify the quantitative effect of these factors on HA. An ethnically homogeneous sample of 911 apparently healthy European-derived individuals, assessed for radiographic hand osteoarthritis (RHOA), HA, leptin, adiponectin, and several anthropometrical measures of obesity-related phenotypes was studied. Model-based quantitative genetic analysis was used to reveal genetic and shared environmental factors affecting the variation of the study's phenotypes. The HA levels significantly correlated with the age, RHOA, adiponectin, obesity-related phenotypes, and the waist-to-hip ratio. The putative genetic effects contributed significantly to the variation of HA (66.2 ± 9.3%) and they were also significant factors in the variations of all the other studied phenotypes, with the heritability estimate ranging between 0.122 ± 4.4% (WHR) and 45.7 ± 2.2% (joint space narrowing). This is the first study to report heritability estimates of HA variation and its correlation with obesity-related phenotypes, ADP and RHOA. However, the nature of genetic effects on HA and its correlation with other study phenotypes require further clarification.

Impact of humic acid on the photoreductive degradation of perfluorooctane sulfonate (PFOS) by UV/Iodide process.

PubMed

Sun, Zhuyu; Zhang, Chaojie; Chen, Pei; Zhou, Qi; Hoffmann, Michael R

2017-12-15

Iodide photolysis under UV illumination affords an effective method to produce hydrated electrons (e aq - ) in aqueous solution. Therefore, UV/Iodide photolysis can be utilized for the reductive degradation of many recalcitrant pollutants. However, the effect of naturally occurring organic matter (NOM) such as humic and fulvic acids (HA/FA), which may impact the efficiency of UV/Iodide photoreduction, is poorly understood. In this study, the UV photoreductive degradation of perfluorooctane sulfonate (PFOS) in the presence of I - and HA is studied. PFOS undergoes a relatively slow direct photoreduction in pure water, a moderate level of degradation via UV/Iodide, but a rapid degradation via UV/Iodide/HA photolysis. After 1.5 h of photolysis, 86.0% of the initial [PFOS] was degraded in the presence of both I - and HA with a corresponding defluorination ratio of 55.6%, whereas only 51.7% of PFOS was degraded with a defluorination ratio of 4.4% via UV/Iodide illumination in the absence of HA. The relative enhancement in the presence of HA in the photodegradation of PFOS can be attributed to several factors: a) HA enhances the effective generation of e aq - due to the reduction of I 2 , HOI, IO 3 - and I 3 - back to I - ; b) certain functional groups of HA (i.e., quinones) enhance the electron transfer efficiency as electron shuttles; c) a weakly-bonded association of I - and PFOS with HA increases the reaction probability; and d) absorption of UV photons by HA itself produces e aq - . The degradation and defluorination efficiency of PFOS by UV/Iodide/HA process is dependent on pH and HA concentration. As pH increases from 7.0 to 10.0, the enhancement effect of HA improves significantly. The optimal HA concentration for the degradation of 0.03 mM PFOS is 1.0 mg L -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Metal mobilization from metallurgical wastes by soil organic acids.

PubMed

Potysz, Anna; Grybos, Malgorzata; Kierczak, Jakub; Guibaud, Gilles; Fondaneche, Patrice; Lens, Piet N L; van Hullebusch, Eric D

2017-07-01

Three types of Cu-slags differing in chemical and mineralogical composition (historical, shaft furnace, and granulated slags) and a matte from a lead recovery process were studied with respect to their susceptibility to release Cu, Zn and Pb upon exposure to organic acids commonly encountered in soil environments. Leaching experiments (24-960 h) were conducted with: i) humic acid (20 mg/L) at pH t 0  = 4.4, ii) fulvic acid (20 mg/L) at pH t 0  = 4.4, iii) an artificial root exudates (ARE) (17.4 g/L) solution at pH t 0  = 4.4, iv) ARE solution at pH t 0  = 2.9 and v) ultrapure water (pH t 0  = 5.6). The results demonstrated that the ARE contribute the most to the mobilization of metals from all the wastes analyzed, regardless of the initial pH of the solution. For example, up to 14%, 30%, 24% and 5% of Cu is released within 960 h from historical, shaft furnace, granulated slags and lead matte, respectively, when exposed to the artificial root exudates solution (pH 2.9). Humic and fulvic acids were found to have a higher impact on granulated and shaft furnace slags as compared to the ultrapure water control and increased the release of metals by a factor up to 37.5 (Pb) and 20.5 (Cu) for granulated and shaft furnace slags, respectively. Humic and fulvic acids amplified the mobilization of metals by a maximal factor of 13.6 (Pb) and 12.1 (Pb) for historical slag and lead matte, respectively. The studied organic compounds contributed to different release rates of metallic contaminants from individual metallurgical wastes under the conditions tested. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acid-base properties of Baltic Sea dissolved organic matter

NASA Astrophysics Data System (ADS)

Hammer, Karoline; Schneider, Bernd; Kuliński, Karol; Schulz-Bull, Detlef E.

2017-09-01

Calculations related to the marine CO2 system that are based on alkalinity data may be strongly biased if the contributions of organic compounds are ignored. In coastal seas, concentrations of dissolved organic matter (DOM) are frequently high and alkalinity from inorganic compounds is low. In this study, based on measurements of total alkalinity, total CO2, and pH, we determined the organic alkalinity, Aorg, in water from the central Baltic Sea. The maximum Aorg measured in the surface mixed layer during the spring bloom was > 50 μmol/kg-SW but the Aorg decreased with depth and approached zero below the permanent halocline. This behavior could be attributed to the decreased pH of deeper water layers. The data were used to calculate the bulk dissociation constant, KDOM, for marine DOM and the fraction f of dissolved organic carbon (DOC) that acts as a carrier for acid-base functional groups. The p KDOM (7.27) agreed well with the value (7.34) previously estimated in a preliminary study of organic alkalinity in the Baltic Sea. The fraction of carbon atoms carrying acid-base groups was 17% and was somewhat higher than previously reported (12%). Spike experiments performed using artificial seawater and three different humic/fulvic substances tested whether the acid-base properties of these substances explain the results of our field study. Specifically, Aorg was determined at different concentrations (DOC) of the added humic/fulvic substances. The relationship between Aorg and the DOC concentrations indicated that humic/fulvic substances are more acidic (p KDOM < 6.5) than the bulk DOC natural occurring in the Baltic Sea.

Biogeochemistry of aquatic humic substances in Thoreau's Bog, Concord, Massachusetts

USGS Publications Warehouse

McKnight, Diane M.; Thurman, E. Michael; Wershaw, Robert L.; Hemond, Herold

1985-01-01

Thoreau's Bog is an ombrotrophic floating—mat Sphagnum bog developed in a glacial kettlehole and surrounded by a red maple swamp. Concentrations of dissolved organic carbon in the porewater of the bog average 36 mg/L and are greatest near the surface, especially during late summer. This distribution suggest that the upper layer of living and dead Sphagnum and moderately humified peat is the major site of dissolved organic material production in the bog. The dissolved organic material consists mainly of aquatic fulvic acid (67%) and hydrophilic acids (20%); these organic acids control the pH (typically 4 or somewhat lower) of the bogwater. The elemental, amino acid, carbohydrate, and carboxylic acid contents of fulvic acid from the bog are similar to those of aquatic fulvic acid from the nearby Shawsheen River, although the phenolic hydroxyl content of fulvic acid from Thoreau's Bog is higher. The hydrophilic acids have greater amino acid, carbohydrate, and carboxylic acid contents than the fulvic acid, consistent with the hypothesis that hydrophilic acids are more labile intermediate compounds in the formation of fulvic acid.

Partitioning of uranyl between ferrihydrite and humic substances at acidic and circum-neutral pH

DOE PAGES

Dublet, Gabrielle; Lezama Pacheco, Juan; Bargar, John R.; ...

2017-07-14

As part of a larger study of the reactivity and mobility of uranyl (U(VI)O 2 2+) cations in subsurface environments containing natural organic matter (NOM) and hydrous ferric oxides, we have examined the effect of reference humic and fulvic substances on the sorption of uranyl on 2-line ferrihydrite (Fh), a common, naturally occurring nano-Fe(III)-hydroxide. Uranyl was reacted with Fh at pH 4.6 and 7.0 in the presence and absence of Elliott Soil Humic Acid (ESHA) (0–835 ppm) or Suwanee River Fulvic Acid (SRFA) (0–955 ppm). Here, no evidence was found for reduction of uranyl by either form of NOM aftermore » 24 h of exposure.« less

Partitioning of uranyl between ferrihydrite and humic substances at acidic and circum-neutral pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dublet, Gabrielle; Lezama Pacheco, Juan; Bargar, John R.

As part of a larger study of the reactivity and mobility of uranyl (U(VI)O 2 2+) cations in subsurface environments containing natural organic matter (NOM) and hydrous ferric oxides, we have examined the effect of reference humic and fulvic substances on the sorption of uranyl on 2-line ferrihydrite (Fh), a common, naturally occurring nano-Fe(III)-hydroxide. Uranyl was reacted with Fh at pH 4.6 and 7.0 in the presence and absence of Elliott Soil Humic Acid (ESHA) (0–835 ppm) or Suwanee River Fulvic Acid (SRFA) (0–955 ppm). Here, no evidence was found for reduction of uranyl by either form of NOM aftermore » 24 h of exposure.« less

Mid-Infrared Spectroscopic Properties of Humic Acid and Fulvic Acid-Soil Mixtures

USDA-ARS?s Scientific Manuscript database

The detection of humic materials in soils is essential in order to determine organic matter (SOM) stability and C sequestration on agricultural land. Mid-Infrared (MidIR) spectroscopy has been used to characterize SOM quality [1], study extracted soil humic acids [2], develop calibrations for quanti...

Mid-Infrared Spectroscopic Properties of Humic Acid and Fulvic Acid-Soil Mixtures.

USDA-ARS?s Scientific Manuscript database

The detection of humic materials in soils is essential in order to determine organic matter (SOM) stability and C sequestration on agricultural land. Mid-Infrared (MidIR) spectroscopy has been used to characterize SOM quality [1], study extracted soil humic acids [2], develop calibrations for quanti...

The Impact of HA Oligomer Content on Physical, Mechanical, and Biologic Properties of Divinyl Sulfone-Crosslinked HA Hydrogels

PubMed Central

Ibrahim, Samir; Kang, Qian K; Ramamurthi, Anand

2009-01-01

In recent studies, we showed that exogenous hyaluronic acid oligomers (HA-o) stimulate functional endothelialization, though native long-chain HA is more bioinert and possibly more biocompatible. Thus, in this study, hydrogels containing high molecular weight (HMW) HA (1×106 Da) and HA oligomer mixtures (HA-o: 0.75–10 kDa) were created by crosslinking with divinyl sulfone (DVS). The incorporation of HA oligomers was found to compromise the physical and mechanical properties of the gels (rheology, apparent crosslinking density, swelling ratio, degradation) and to very mildly enhance inflammatory cell recruitment in vivo; increasing the DVS crosslinker content within the gels in general, had the opposite effect, though the relatively high concentration of DVS within these gels (necessary to create a solid gel) also stimulated a mild sub-cutaneous inflammatory response in vivo and VCAM-1 expression by ECs cultured atop; ICAM-expression levels remained very low irrespective extent of DVS crosslinking or HA-o content. The greatest EC attachment and proliferation (MTT assay) was observed on gels that contained the highest amount of HA-o. The study shows that the beneficial EC response to HA oligomers and biocompatibility of HA is mostly unaltered by their chemical derivatization and crosslinking into a hydrogel. However, the study also demonstrates that the relatively high concentrations of DVS, necessary to create solid gels, compromises their biocompatibility. Moreover, the poor mechanics of even these heavily crosslinked gels, in the context of vascular implantation, necessitates the investigation of other, more appropriate crosslinking agents. Alternately, the outcomes of this study may be used to guide an approach based on chemical immobilization and controlled surface-presentation of both bioactive HA oligomers and more biocompatible HMW HAon synthetic or tissue engineered grafts already in use, without the use of a crosslinker, so that improved, predictable

Calcite crystal growth inhibition by humic substances with emphasis on hydrophobic acids from the Florida Everglades

USGS Publications Warehouse

Hoch, A.R.; Reddy, M.M.; Aiken, G.R.

2000-01-01

The crystallization of calcium carbonate minerals plays an integral role in the water chemistry of terrestrial ecosystems. Humic substances, which are ubiquitous in natural waters, have been shown to reduce or inhibit calcite crystal growth in experiments. The purpose of this study is to quantify and understand the kinetic effects of hydrophobic organic acids isolated from the Florida Everglades and a fulvic acid from Lake Fryxell, Antarctica, on the crystal growth of calcite (CaCO3). Highly reproducible calcite growth experiments were performed in a sealed reactor at constant pH, temperature, supersaturation (?? = 4.5), P(CO2) (10-3.5atm), and ionic strength (0.1 M) with various concentrations of organic acids. Higher plant-derived aquatic hydrophobic acids from the Everglades were more effective growth inhibitors than microbially derived fulvic acid from Lake Fryxell. Organic acid aromaticity correlated strongly with growth inhibition. Molecular weight and heteroatom content correlated well with growth inhibition, whereas carboxyl content and aliphatic nature did not. Copyright (C) 1999 Elsevier Science Ltd.

Characterizing the release of different composition of dissolved organic matter in soil under acid rain leaching using three-dimensional excitation-emission matrix spectroscopy.

PubMed

Liu, Li; Song, Cunyi; Yan, Zengguang; Li, Fasheng

2009-09-01

Although excitation-emission matrix spectroscopy (EEMS) has been widely used to characterize dissolved organic matter (DOM), there has no report that EEMS has been used to study the effects of acid rain on DOM and its composition in soil. In this work, we employed three-dimensional EEMS to characterize the compositions of DOM leached by simulated acid rain from red soil. The red soil was subjected to leaching of simulated acid rain of different acidity, and the leached DOM presented five main peaks in its EEMS: peak-A, related to humic acid-like (HA-like) material, at Ex/Em of 310-330/395-420nm; peak-B, related to UV fulvic acid-like (FA-like) material, at Ex/Em of 230-280/400-435nm; peak-C and peak-D, both related to microbial byproduct-like material, at Ex/Em of 250-280/335-355nm and 260-280/290-320nm, respectively; and peak-E, related to simple aromatic proteins, at Ex/Em of 210-240/290-340nm. EEMS analysis results indicated that most DOM could be lost from red soil in the early phase of acid rain leaching. In addition to the effects of the pH of acid rain, the loss of DOM also depended on the properties of its compositions and the solubility of their complexes with aluminum. HA-like and microbial byproduct-like materials could be more easily released from red soil by acid rain at both higher pH (4.5 and 5.6) and lower pH (2.5 and 3) than that at middle pH (3.5). On the contrary, FA-like material lost in a similar manner under the action of different acid rains with pH ranging from 2.5 to 5.6.

Binding of polychlorinated biphenyls to aquatic humic substances: The role of substrate and sorbate properties on partitioning

USGS Publications Warehouse

Uhle, M.E.; Chin, Y.-P.; Aiken, G.R.; McKnight, Diane M.

1999-01-01

Two ortho- (2,2',5 and 2,2',5,6') and a non-ortho- (3,3',4,4') substituted polychlorinated biphenyl (PCB) congeners were used to study the effects of sorbate structure in binding processes to two lacustrine fulvic acids. Binding constants were determined by solubility enhancement of the solutes by the fulvic acids. The binding of the ortho-trichlorobiphenyl was significantly less than the non-ortho-substituted tetrachlorobiphenyl to both fulvic acids. Surprisingly, the measured ortho-trichlorobiphenyl binding constant to both fulvic acids was approximately the same as the ortho- substituted tetrachlorobiphenyl. The effect of the chlorines in the ortho position inhibits free rotation around the 1,1' carbon bond, thereby making the molecule less able to interact effectively with the fulvic acid substrate relative to its non-ortho-substituted congeners. Finally, binding of all three PCBs to the Great Dismal Swamp fulvic acid was significantly higher than for the Pony Lake sample. This observation is attributable to the former substrate's higher degree of aromaticity and polarizability, which can potentially interact more favorably with the PCBs through an increase in van der Waals type interactions.Two ortho- (2,2???,5 and 2,2???,5,6???) and a non-ortho- (3,3???,4,4???) substituted polychlorinated biphenyl (PCB) congeners were used to study the effects of sorbate structure in binding processes to two lacustrine fulvic acids. Binding constants were determined by solubility enhancement of the solutes by the fulvic acids. The binding of the ortho-trichlorobiphenyl was significantly less than the non-ortho-substituted tetrachlorobiphenyl to both fulvic acids. Surprisingly, the measured ortho-trichlorobiphenyl binding constant to both fulvic acids was approximately the same as the ortho-substituted tetrachlorobiphenyl. The effect of the chlorines in the ortho position inhibits free rotation around the 1,1??? carbon bond, thereby making the molecule less able to interact

Covalent binding of aniline to humic substances. 1. Kinetic studies

USGS Publications Warehouse

Weber, E.J.; Spidle, D.L.; Thorn, K.A.

1996-01-01

The reaction kinetics for the covalent binding of aniline with reconstituted IHSS humic and fulvic acids, unfractionated DOM isolated from Suwannee River water, and whole samples of Suwannee River water have been investigated. The reaction kinetics in each of these systems can be adequately described by a simple second-order rate expression. The effect of varying the initial concentration of aniline on reaction kinetics suggested that approximately 10% of the covalent binding sites associated with Suwannee River fulvic acid are highly reactive sites that are quickly saturated. Based on the kinetic parameters determined for the binding of aniline with the Suwannee River fulvic and humic acid isolates, it was estimated that 50% of the aniline concentration decrease in a Suwannee River water sample could be attributed to reaction with the fulvic and humic acid components of the whole water sample. Studies with Suwannee River fulvic acid demonstrated that the rate of binding decreased with decreasing pH, which parallels the decrease in the effective concentration of the neutral form, or reactive nucleophilic species of aniline. The covalent binding of aniline with Suwannee River fulvic acid was inhibited by prior treatment of the fulvic acid with hydrogen sulfide, sodium borohydride, or hydroxylamine. These observations are consistent with a reaction pathway involving nucleophilic addition of aniline to carbonyl moieties present in the fulvic acid.

Extraction of hyaluronic acid (HA) from rooster comb and characterization using flow field-flow fractionation (FlFFF) coupled with multiangle light scattering (MALS).

PubMed

Kang, Dong Young; Kim, Won-Suk; Heo, In Sook; Park, Young Hun; Lee, Seungho

2010-11-01

Hyaluronic acid (HA) was extracted in a relatively large scale from rooster comb using a method similar to that reported previously. The extraction method was modified to simplify and to reduce time and cost in order to accommodate a large-scale extraction. Five hundred grams of frozen rooster combs yielded about 500 mg of dried HA. Extracted HA was characterized using asymmetrical flow field-flow fractionation (AsFlFFF) coupled online to a multiangle light scattering detector and a refractive index detector to determine the molecular size, molecular weight (MW) distribution, and molecular conformation of HA. For characterization of HA, AsFlFFF was operated by a simplified two-step procedure, instead of the conventional three-step procedure, where the first two steps (sample loading and focusing) were combined into one to avoid the adsorption of viscous HA onto the channel membrane. The simplified two-step AsFlFFF yielded reasonably good separations of HA molecules based on their MWs. The weight average MW (M(w) ) and the average root-mean-square (RMS) radius of HA extracted from rooster comb were 1.20×10(6) and 94.7 nm, respectively. When the sample solution was filtered through a 0.45 μm disposable syringe filter, they were reduced down to 3.8×10(5) and 50.1 nm, respectively. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synergistic interaction of platelet derived growth factor (PDGF) with the surface of PLLA/Col/HA and PLLA/HA scaffolds produces rapid osteogenic differentiation.

PubMed

Raghavendran, Hanumantha Rao Balaji; Mohan, Saktiswaren; Genasan, Krishnamurithy; Murali, Malliga Raman; Naveen, Sangeetha Vasudevaraj; Talebian, Sepehr; McKean, Robert; Kamarul, Tunku

2016-03-01

Scaffolds with structural features similar to the extracellular matrix stimulate rapid osteogenic differentiation in favorable microenvironment and with growth factor supplementation. In this study, the osteogenic potential of electrospun poly-l-lactide/hydroxyapatite/collagen (PLLA/Col/HA, PLLA/HA and PLLA/Col) scaffolds were tested in vitro with the supplementation of platelet derived growth factor-BB (PDGF-BB). Cell attachment and topography, mineralization, extracellular matrix protein localization, and gene expression of the human mesenchymal stromal cells were compared between the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA. The levels of osteocalcin, calcium, and mineralization were significantly greater in the PLLA/Col/HA and PLLA/HA compared with PLLA/Col. High expression of fibronectin, intracellular adhesion molecule, cadherin, and collagen 1 (Col1) suggests that PLLA/Col/HA and PLLA/HA scaffolds had superior osteoinductivity than PLLA/Col. Additionally, osteopontin, osteocalcin, osterix, Runt-related transcription factor 2 (Runx2), and bone morphogenic protein (BMP2) expression were higher in PLLA/Col/HA and PLLA/HA compared with PLLA/Col. In comparison with PLLA/Col, the PLLA/Col/HA and PLLA/HA scaffolds presented a significant upregulation of the genes Runx2, Col 1, Integrin, osteonectin (ON), bone gamma-carboxyglutamic acid-containing protein (BGALP), osteopontin (OPN), and BMP2. The upregulation of these genes was further increased with PDGF-BB supplementation. These results show that PDGF-BB acts synergistically with PLLA/Col/HA and PLLA/HA to enhance the osteogenic differentiation potential. Therefore, this combination can be used for the rapid expansion of bone marrow stromal cells into bone-forming cells for tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

Production of poly(β-l-malic acid) by Aureobasidium pullulans HA-4D under solid-state fermentation.

PubMed

Xia, Jun; Li, Rongqing; He, Aiyong; Xu, Jiaxing; Liu, Xiaoyan; Li, Xiangqian; Xu, Jiming

2017-11-01

Poly(β-l-malic acid) (PMA) production by Aureobasidium pullulans HA-4D was carried out through solid-state fermentation (SSF) using agro-industrial residues. Maximum PMA production (75.4mg/g substrate) was obtained from a mixed substrate of sweet potato residue and wheat bran (1:1, w/w) supplemented with NaNO 3 (0.8%, w/w) and CaCO 3 (2%, w/w), with an initial moisture content of 70% and inoculum size of 13% (v/w) for 8days. Repeated-batch SSF was successfully conducted for 5 cycles with a high productivity. The scanning electron microscopy showed that the yeast-like cells of A. pullulans HA-4D could grow well on the solid substrate surface. Moreover, the cost analysis showed that the unit price of PMA in SSF was much lower than that of SmF. This is the first report on PMA production via SSF, and this study provided a new method to produce PMA from inexpensive agro-industrial residues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Highly stretchable HA/SA hydrogels for tissue engineering.

PubMed

Zhu, Chengcheng; Yang, Rui; Hua, Xiaobin; Chen, Hong; Xu, Jumei; Wu, Rile; Cen, Lian

2018-04-01

A highly stretchable hyaluronic acid (HA)/sodium alginate (SA) hydrogel was developed in this study based on an interpenetrating polymer network. HA/SA hydrogels were prepared by mixing two polysaccharides followed by covalent crosslinking via epoxy groups on HA molecules and ionic crosslinking via divalent ions on SA chains sequentially. The effect of HA/SA ratio on the pore size and distribution, swelling ratio, elongation and rheological properties as well as protein loading and release properties of HA/SA hydrogels was explored. Moreover, a surface modification method, layer-by-layer (LBL) assembly technique, was applied to modify the hydrogel to evaluate the hydrogel's tenability in varying biological performance. It was then shown that the hydrogels had the pore sizes ranging from 100 to 50 μm. With the increase in SA content of the resulting hydrogels, the pore size, swelling ratio, and storage modulus (G') and loss modulus (G″) of the hydrogel all decreased, whereas the in vitro bulk weight loss was fastened. Moreover, elongation at break (EB) value increased first, reached a peak value and then decreased, that is HA8/SA1 (HA:SA = 8:1) had the highest EB value of 417%. This hydrogel could retain 33.2% of the pre-loaded protein even after 72 h, which could be further attenuated when LBL was used to shell the hydrogel. The growth of fibroblasts on HA8/SA1 hydrogel gave preliminary assessment on its suitability as a cellular carrier, while the LBL modified HA8/SA1 hydrogel also favored the anchoring of keratinocytes, further enhancing its cell carrier role for tissue regeneration, especially skin engineering.

A phase IIa study of HA-irinotecan, formulation of hyaluronic acid and irinotecan targeting CD44 in extensive-stage small cell lung cancer.

PubMed

Alamgeer, Muhammad; Neil Watkins, D; Banakh, Ilia; Kumar, Beena; Gough, Daniel J; Markman, Ben; Ganju, Vinod

2018-04-01

Preclinical studies in small cell lung cancer (SCLC) have shown that hyaluronic acid (HA) can be effectively used to deliver chemotherapy and selectively decrease CD44 expressing (stem cell-like) tumour cells. The current study aimed to replicate these findings and obtain data on safety and activity of HA-irinotecan (HA-IR). Eligible patients with extensive stage SCLC were consented. A safety cohort (n = 5) was treated with HA-IR and Carboplatin (C). Subsequently, the patients were randomised 1:1 to receive experimental (HA-IR + C) or standard (IR + C) treatment, to a maximum of 6 cycles. The second line patients were added to the study and treated with open label HA-IR + C. Tumour response was measured after every 2 cycles. Baseline tumour specimens were stained for CD44s and CD44v6 expression. Circulating tumour cells (CTCs) were enumerated before each treatment cycle. Out of 39 patients screened, 34 were evaluable for the study. The median age was 66 (range 39-83). The overall response rates were 69% and 75% for experimental and standard arms respectively. Median progression free survival was 42 and 28 weeks, respectively (p = 0.892). The treatments were well tolerated. The incidence of grade III/IV diarrhea was more common in the standard arm, while anaemia was more common in the experimental arm. IHC analysis suggested that the patients with CD44s positive tumours may gain survival benefit from HA-IR. HA-IR is well tolerated and active in ES-SCLC. The effect of HA-IR on CD44s + cancer stem-like cells provide an early hint towards a potential novel target.

Sugar-binding sites of the HA1 subcomponent of Clostridium botulinum type C progenitor toxin.

PubMed

Nakamura, Toshio; Tonozuka, Takashi; Ide, Azusa; Yuzawa, Takayuki; Oguma, Keiji; Nishikawa, Atsushi

2008-02-22

Clostridium botulinum type C 16S progenitor toxin contains a hemagglutinin (HA) subcomponent, designated HA1, which appears to play an important role in the effective internalization of the toxin in gastrointestinal epithelial cells and in creating a broad specificity for the oligosaccharide structure that corresponds to various targets. In this study, using the recombinant protein fused to glutathione S-transferase, we investigated the binding specificity of the HA1 subcomponent to sugars and estimated the binding sites of HA1 based on X-ray crystallography and soaking experiments using various sugars. N-Acetylneuraminic acid, N-acetylgalactosamine, and galactose effectively inhibited the binding that occurs between glutathione S-transferase-HA1 and mucins, whereas N-acetylglucosamine and glucose did not inhibit it. The crystal structures of HA1 complex with N-acetylneuraminic acid, N-acetylgalactosamine, and galactose were also determined. There are two sugar-binding sites, sites I and II. Site I corresponds to the electron densities noted for all sugars and is located at the C-terminal beta-trefoil domain, while site II corresponds to the electron densities noted only for galactose. An aromatic amino acid residue, Trp176, at site I has a stacking interaction with the hexose ring of the sugars. On the other hand, there is no aromatic residue at site II; thus, the interaction with galactose seems to be poor. The double mutant W176A at site I and D271F at site II has no avidity for N-acetylneuraminic acid but has avidity for galactose. In this report, the binding specificity of botulinum C16S toxin HA1 to various sugars is demonstrated based on its structural features.

Osteogenic properties of PBLG-g-HA/PLLA nanocomposites.

PubMed

Liao, Lan; Yang, Shuang; Miron, Richard J; Wei, Junchao; Zhang, Yufeng; Zhang, Meng

2014-01-01

New development of biomaterial scaffolds remains a prominent issue for the regeneration of lost or fractured bone. Of these scaffolds, a number of bioactive polymers have been synthesized and fabricated for diverse biological roles. Although recent evidence has demonstrated that composite scaffolds such as HA/PLLA have improved properties when compared to either HA or PLLA alone, recent investigations have demonstrated that the phase compatibility between HA and PLLA layers is weak preventing optimal enhancement of the mechanical properties and making the composites prone to breakdown. In the present study, poly (γ-benzyl-L-glutamate) modified hydroxyapatite/(poly (L-lactic acid)) (PBLG-g-HA/PLLA) composite scaffolds were fabricated with improved phase compatibility and tested for their osteogenic properties in 18 Wistar female rats by analyzing new bone formation in 3 mm bilateral femur defects in vivo. At time points, 2, 4 and 8 weeks post surgery, bone formation was evaluated by µ-CT and histological analysis by comparing 4 treatment groups; 1) blank defect, 2) PLLA, 3) HA/PLLA and 4) PBLG-g-HA/PLLA scaffolds. The in vivo analysis demonstrated that new bone formation was much more prominent in HA/PLLA and PBLG-g-HA/PLLA groups as depicted by µ-CT, H&E staining and immunohistochemistry for collagen I. TRAP staining was also utilized to determine the influence of osteoclast cell number and staining intensity to the various scaffolds. No significant differences in either staining intensity or osteoclast numbers between all treatment modalities was observed, however blank defects did contain a higher number of osteoclast-like cells. The results from the present study illustrate the potential of PBLG-g-HA/PLLA scaffolds for bone tissue engineering applications by demonstrating favorable osteogenic properties.

- and Cross-Polarization 13C NMR Evidence of Alterations in Molecular Composition of Humic Substances Following Afforestation with Eucalypt in Distinct Brazilian Biomes

NASA Astrophysics Data System (ADS)

Silva, I. R.; Soares, E. M.; Schmidt-Rohr, K.; Novais, R.; Barros, N.; Fernandes, S.

2010-12-01

The effect of planting fast growing tree species on SOM quality in tropical regions has been overlooked. In the present study 13C-NMR approaches were used to evaluate the impact of eucalypt cultivation on humic and fulvic acids molecular composition. The results indicate that the replacement of native vegetation by eucalypt plantations increased the relative contribution of aliphatic groups in HA from soils previously under Atlantic Forest, Grassland, and the Cerrado (Curvelo site only). The same trend was observed for FA, except in the Curvelo site. A trend for degradation and smaller contribution of O-alkyl C (carbohydrates) in HA was observed in soils under eucalyptus in Atlantic Forest and Cerrado. For FA such decreases were seen in Cerrado and Grassland biomes after eucalypt planting. In the area cultivated with pasture in the Atlantic Forest biome and in the Grassland soil, the largest contributions of lignin-derived compounds were detected in HA. The HA from the Cerrado at the Curvelo site, where the woody vegetation is virtually devoid of grassy species, showed the lowest intensity of lignin signal then those from the Cerrado sensu stricto in Itacambira, where grass species are more abundant. At our study sites, charred material are most likely derived from burning of the native vegetation, as naturally occurs in the Cerrado region, or anthropogenic fires in the Grassland biome. Burning of harvest residues in eucalypt fields was also a common practice in the early rotations. The replacement of native vegetation by eucalypt plantations increases the relative contribution of nonpolar alkyl groups in HA from soils previously under Atlantic Forest, Grassland, and the Cerrado (Curvelo site only) biomes. There is evidence of substantial contribution of lignin-derived C to HA and FA, especially in sites planted with Brachiaria sp pastures. Eucalypt introduction decreases the relative contribution of carbohydrates in HA and FA. 13C DP/MAS NMR functional groups in

Structural characterization of aquatic humic material. 2. Phenolic content and its relationship to chlorination mechanism in an isolated aquatic fulvi acid

USGS Publications Warehouse

Norwood, D.L.; Christman, R.F.; Hatcher, P.G.

1987-01-01

The complementary techniques of solid-state 13G nuclear magnetic resonance spectroscopy and chemical degradation were utilized to examine the lignin/phenolic substructure of an isolated aquatic fulvic acid capable of producing upon aqueous chlorination a number of organohalides typically found in municipal drinking water. Results indicate that while phenolic moieties are present in the fulvic acid, they account for only a minor fraction of the total carbon. A sequential chemical degradation experiment utilizing aqueous chlorine and CuO demonstrated that the lignin/phenolic substructure was attacked by the chlorine. It is concluded that while phenolic ring rupture mechanisms appear to be important in organohalide generation, other aqueous chlorination mechanisms involving aliphatic and other types of aromatic structures should also be considered. ?? 1987 American Chemical Society.

Effectiveness of Losartan-Loaded Hyaluronic Acid (HA) Micelles for the Reduction of Advanced Hepatic Fibrosis in C3H/HeN Mice Model

PubMed Central

Thomas, Reju George; Moon, Myeong Ju; Kim, Jo Heon; Lee, Jae Hyuk; Jeong, Yong Yeon

2015-01-01

Advanced hepatic fibrosis therapy using drug-delivering nanoparticles is a relatively unexplored area. Angiotensin type 1 (AT1) receptor blockers such as losartan can be delivered to hepatic stellate cells (HSC), blocking their activation and thereby reducing fibrosis progression in the liver. In our study, we analyzed the possibility of utilizing drug-loaded vehicles such as hyaluronic acid (HA) micelles carrying losartan to attenuate HSC activation. Losartan, which exhibits inherent lipophilicity, was loaded into the hydrophobic core of HA micelles with a 19.5% drug loading efficiency. An advanced liver fibrosis model was developed using C3H/HeN mice subjected to 20 weeks of prolonged TAA/ethanol weight-adapted treatment. The cytocompatibility and cell uptake profile of losartan-HA micelles were studied in murine fibroblast cells (NIH3T3), human hepatic stellate cells (hHSC) and FL83B cells (hepatocyte cell line). The ability of these nanoparticles to attenuate HSC activation was studied in activated HSC cells based on alpha smooth muscle actin (α-sma) expression. Mice treated with oral losartan or losartan-HA micelles were analyzed for serum enzyme levels (ALT/AST, CK and LDH) and collagen deposition (hydroxyproline levels) in the liver. The accumulation of HA micelles was observed in fibrotic livers, which suggests increased delivery of losartan compared to normal livers and specific uptake by HSC. Active reduction of α-sma was observed in hHSC and the liver sections of losartan-HA micelle-treated mice. The serum enzyme levels and collagen deposition of losartan-HA micelle-treated mice was reduced significantly compared to the oral losartan group. Losartan-HA micelles demonstrated significant attenuation of hepatic fibrosis via an HSC-targeting mechanism in our in vitro and in vivo studies. These nanoparticles can be considered as an alternative therapy for liver fibrosis. PMID:26714035

Effectiveness of Losartan-Loaded Hyaluronic Acid (HA) Micelles for the Reduction of Advanced Hepatic Fibrosis in C3H/HeN Mice Model.

PubMed

Thomas, Reju George; Moon, Myeong Ju; Kim, Jo Heon; Lee, Jae Hyuk; Jeong, Yong Yeon

2015-01-01

Advanced hepatic fibrosis therapy using drug-delivering nanoparticles is a relatively unexplored area. Angiotensin type 1 (AT1) receptor blockers such as losartan can be delivered to hepatic stellate cells (HSC), blocking their activation and thereby reducing fibrosis progression in the liver. In our study, we analyzed the possibility of utilizing drug-loaded vehicles such as hyaluronic acid (HA) micelles carrying losartan to attenuate HSC activation. Losartan, which exhibits inherent lipophilicity, was loaded into the hydrophobic core of HA micelles with a 19.5% drug loading efficiency. An advanced liver fibrosis model was developed using C3H/HeN mice subjected to 20 weeks of prolonged TAA/ethanol weight-adapted treatment. The cytocompatibility and cell uptake profile of losartan-HA micelles were studied in murine fibroblast cells (NIH3T3), human hepatic stellate cells (hHSC) and FL83B cells (hepatocyte cell line). The ability of these nanoparticles to attenuate HSC activation was studied in activated HSC cells based on alpha smooth muscle actin (α-sma) expression. Mice treated with oral losartan or losartan-HA micelles were analyzed for serum enzyme levels (ALT/AST, CK and LDH) and collagen deposition (hydroxyproline levels) in the liver. The accumulation of HA micelles was observed in fibrotic livers, which suggests increased delivery of losartan compared to normal livers and specific uptake by HSC. Active reduction of α-sma was observed in hHSC and the liver sections of losartan-HA micelle-treated mice. The serum enzyme levels and collagen deposition of losartan-HA micelle-treated mice was reduced significantly compared to the oral losartan group. Losartan-HA micelles demonstrated significant attenuation of hepatic fibrosis via an HSC-targeting mechanism in our in vitro and in vivo studies. These nanoparticles can be considered as an alternative therapy for liver fibrosis.

Generation of recombinant pandemic H1N1 influenza virus with the HA cleavable by bromelain and identification of the residues influencing HA bromelain cleavage.

PubMed

Wang, Weijia; Suguitan, Amorsolo L; Zengel, James; Chen, Zhongying; Jin, Hong

2012-01-20

The proteolytic enzyme bromelain has been traditionally used to cleave the hemagglutinin (HA) protein at the C-terminus of the HA2 region to release the HA proteins from influenza virions. The bromelain cleaved HA (BHA) has been routinely used as an antigen to generate antiserum that is essential for influenza vaccine product release. The HA of the 2009 pandemic H1N1 influenza A/California/7/2009 (CA09) virus could not be cleaved efficiently by bromelain. To ensure timely delivery of BHA for antiserum production, we generated a chimeric virus that contained the HA1 region from CA09 and the HA2 region from the seasonal H1N1 A/South Dakota/6/2007 (SD07) virus that is cleavable by bromelain. The BHA from this chimeric virus was antigenically identical to CA09 and induced high levels of HA-specific antibodies and protected ferrets from wild-type H1N1 CA09 virus challenge. To determine the molecular basis of inefficient cleavage of CA09 HA by bromelain, the amino acids that differed between the HA2 of CA09 and SD07 were introduced into recombinant CA09 virus to assess their effect on bromelain cleavage. The D373N or E374G substitution in the HA2 stalk region of CA09 HA enabled efficient cleavage of CA09 HA by bromelain. Sequence analysis of the pandemic H1N1-like viruses isolated from 2010 revealed emergence of the E374K change. We found that K374 enabled the HA to be cleaved by bromelain and confirmed that the 374 residue is critical for HA bromelain cleavage. Copyright © 2011 Elsevier Ltd. All rights reserved.

Influence of the concentrations of hyaluronic acid on the properties and biocompatibility of Cs-Gel-HA membranes.

PubMed

Liu, Haifeng; Yin, Yuji; Yao, Kangde; Ma, Dongrui; Cui, Lei; Cao, Yilin

2004-08-01

The object of this study was to investigate the relationship between the concentrations of HA solutions and the physicochemical properties and the biocompatibility of Cs-Gel-HA membranes. The addition of different concentrations of HA not only improved the wettability significantly and extended the degradation time of Cs-Gel-HA membranes, but also changed their mechanical properties. The concentration of HA had a significant influence on the biocompatibility of Cs-Gel-HA membranes. Results demonstrated that it was only the concentrations of HA in a certain range (0.01-0.1%), that could promote the cell adhesion, migration and proliferation, while the concentration of HA was above 0.1% it would either reduce or even inhibit these behaviors.

Capacity of humic substances to complex with iron at different salinities in the Yangtze River estuary and East China Sea.

PubMed

Yang, Rujun; Su, Han; Qu, Shenglu; Wang, Xuchen

2017-05-03

The iron binding capacities (IBC) of fulvic acid (FA) and humic acid (HA) were determined in the salinity range from 5 to 40. The results indicated that IBC decreased while salinity increased. In addition, dissolved iron (dFe), FA and HA were also determined along the Yangtze River estuary's increasing salinity gradient from 0.14 to 33. The loss rates of dFe, FA and HA in the Yangtze River estuary were up to 96%, 74%, and 67%, respectively. The decreases in dFe, FA and HA, as well as the change in IBC of humic substances (HS) along the salinity gradient in the Yangtze River estuary were all well described by a first-order exponential attenuation model: y(dFe/FA/HA, S) = a 0 × exp(kS) + y 0 . These results indicate that flocculation of FA and HA along the salinity gradient resulted in removal of dFe. Furthermore, the exponential attenuation model described in this paper can be applied in the major estuaries of the world where most of the removal of dFe and HS occurs where freshwater and seawater mix.

N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society

USGS Publications Warehouse

Thorn, K.A.; Cox, L.G.

2009-01-01

The naturally abundant nitrogen in soil and aquatic NOM samples from the International Humic Substances Society has been characterized by solid state CP/MAS 15N NMR. Soil samples include humic and fulvic acids from the Elliot soil, Minnesota Waskish peat and Florida Pahokee peat, as well as the Summit Hill soil humic acid and the Leonardite humic acid. Aquatic samples include Suwannee River humic, fulvic and reverse osmosis isolates, Nordic humic and fulvic acids and Pony Lake fulvic acid. Additionally, Nordic and Suwannee River XAD-4 acids and Suwannee River hydrophobic neutral fractions were analyzed. Similar to literature reports, amide/aminoquinone nitrogens comprised the major peaks in the solid state spectra of the soil humic and fulvic acids, along with heterocyclic and amino sugar/terminal amino acid nitrogens. Spectra of aquatic samples, including the XAD-4 acids, contain resolved heterocyclic nitrogen peaks in addition to the amide nitrogens. The spectrum of the nitrogen enriched, microbially derived Pony Lake, Antarctica fulvic acid, appeared to contain resonances in the region of pyrazine, imine and/or pyridine nitrogens, which have not been observed previously in soil or aquatic humic substances by 15N NMR. Liquid state 15N NMR experiments were also recorded on the Elliot soil humic acid and Pony Lake fulvic acid, both to examine the feasibility of the techniques, and to determine whether improvements in resolution over the solid state could be realized. For both samples, polarization transfer (DEPT) and indirect detection (1H-15N gHSQC) spectra revealed greater resolution among nitrogens directly bonded to protons. The amide/aminoquinone nitrogens could also be observed by direct detection experiments.

3D fabrication and characterization of phosphoric acid scaffold with a HA/β-TCP weight ratio of 60:40 for bone tissue engineering applications.

PubMed

Wang, Yanen; Wang, Kai; Li, Xinpei; Wei, Qinghua; Chai, Weihong; Wang, Shuzhi; Che, Yu; Lu, Tingli; Zhang, Bo

2017-01-01

A key requirement for three-dimensional printing (3-DP) at room temperature of medical implants depends on the availability of printable and biocompatible binder-powder systems. Different concentration polyvinyl alcohol (PVA) and phosphoric acid solutions were chosen as the binders to make the artificial stent biocompatible with sufficient compressive strength. In order to achieve an optimum balance between the bioceramic powder and binder solution, the biocompatibility and mechanical properties of these artificial stent samples were tested using two kinds of binder solutions. This study demonstrated the printable binder formulation at room temperature for the 3D artificial bone scaffolds. 0.6 wt% PVA solution was ejected easily via inkjet printing, with a supplementation of 0.25 wt% Tween 80 to reduce the surface tension of the polyvinyl alcohol solution. Compared with the polyvinyl alcohol scaffolds, the phosphoric acid scaffolds had better mechanical properties. Though both scaffolds supported the cell proliferation, the absorbance of the polyvinyl alcohol scaffolds was higher than that of the phosphoric acid scaffolds. The artificial stents with a hydroxyapatite/beta-tricalcium phosphate (HA/β-TCP) weight ratios of 60:40 depicted good biocompatibility for both scaffolds. Considering the scaffolds' mechanical and biocompatible properties, the phosphoric acid scaffolds with a HA/β-TCP weight ratio of 60:40 may be the best combination for bone tissue engineering applications.

Copper speciation and binding by organic matter in copper-contaminated streamwater

USGS Publications Warehouse

Breault, R.F.; Colman, J.A.; Aiken, G.R.; McKnight, D.

1996-01-01

Fulvic acid binding sites (1.3-70 ??M) and EDTA (0.0017-0.18 ??M) accounted for organically bound Cu in seven stream samples measured by potentiometric titration. Cu was 84-99% organically bound in filtrates with 200 nM total Cu. Binding of Cu by EDTA was limited by competition from other trace metals. Water hardness was inversely related to properties of dissolved organic carbon (DOC) that enhance fulvic acid binding: DOC concentration, percentage of DOC that is fulvic acid, and binding sites per fulvic acid carbon. Dissolved trace metals, stabilized by organic binding, occurred at increased concentration in soft water as compared to hard water.

Hyaluronan (HA) interacting proteins RHAMM and hyaluronidase impact prostate cancer cell behavior and invadopodia formation in 3D HA-based hydrogels.

PubMed

Gurski, Lisa A; Xu, Xian; Labrada, Lyana N; Nguyen, Ngoc T; Xiao, Longxi; van Golen, Kenneth L; Jia, Xinqiao; Farach-Carson, Mary C

2012-01-01

To study the individual functions of hyaluronan interacting proteins in prostate cancer (PCa) motility through connective tissues, we developed a novel three-dimensional (3D) hyaluronic acid (HA) hydrogel assay that provides a flexible, quantifiable, and physiologically relevant alternative to current methods. Invasion in this system reflects the prevalence of HA in connective tissues and its role in the promotion of cancer cell motility and tissue invasion, making the system ideal to study invasion through bone marrow or other HA-rich connective tissues. The bio-compatible cross-linking process we used allows for direct encapsulation of cancer cells within the gel where they adopt a distinct, cluster-like morphology. Metastatic PCa cells in these hydrogels develop fingerlike structures, "invadopodia", consistent with their invasive properties. The number of invadopodia, as well as cluster size, shape, and convergence, can provide a quantifiable measure of invasive potential. Among candidate hyaluronan interacting proteins that could be responsible for the behavior we observed, we found that culture in the HA hydrogel triggers invasive PCa cells to differentially express and localize receptor for hyaluronan mediated motility (RHAMM)/CD168 which, in the absence of CD44, appears to contribute to PCa motility and invasion by interacting with the HA hydrogel components. PCa cell invasion through the HA hydrogel also was found to depend on the activity of hyaluronidases. Studies shown here reveal that while hyaluronidase activity is necessary for invadopodia and inter-connecting cluster formation, activity alone is not sufficient for acquisition of invasiveness to occur. We therefore suggest that development of invasive behavior in 3D HA-based systems requires development of additional cellular features, such as activation of motility associated pathways that regulate formation of invadopodia. Thus, we report development of a 3D system amenable to dissection of

Size-Controlled TiO(2) nanocrystals with exposed {001} and {101} facets strongly linking to graphene oxide via p-Phenylenediamine for efficient photocatalytic degradation of fulvic acids.

PubMed

Yan, Wen-Yuan; Zhou, Qi; Chen, Xing; Yang, Yong; Zhang, Yong; Huang, Xing-Jiu; Wu, Yu-Cheng

2016-08-15

Photocatalytic degradation is one of the most promising methods for removal of fulvic acids (FA), which is a typical category of natural organic contamination in groundwater. In this paper, TiO2/graphene nanocomposites (N-RGO/TiO2) were prepared via simple chemical functionalization and one-step hydrothermal method for efficient photodegradation of FA under illumination of a xenon lamp as light source. Here, p-phenylenediamine was used as not only the linkage chemical agent between TiO2 nanocrystals and graphene, but also the nitrogen dopant for TiO2 nanocrystals and graphene. During the hydrothermal process, facets of TiO2 nanocrystals were modulated with addition of HF, and sizes of TiO2 nanocrystals were controlled by the contents of graphene oxide functionalized with p-phenylenediamine (RGO-NH2). The obtained N-RGO/TiO2 nanocomposites exhibited a much higher photocatalytic activity and stability for degradation of methyl blue (MB) and FA compared with other TiO2 samples under xenon lamp irradiation. For the third cycle, the 10wt%N-RGO/TiO2 catalyst maintains high photoactivity (87%) for the degradation of FA, which is much better than the TiO2-N/F (61%) in 3h. This approach supplies a new strategy to design and synthesize metal oxide and graphene oxide nanocomposites with highly efficient photocatalytic performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of isolated fractions of dissolved organic matter derived from municipal solid waste compost.

PubMed

Yu, Minda; He, Xiaosong; Liu, Jiaomei; Wang, Yuefeng; Xi, Beidou; Li, Dan; Zhang, Hui; Yang, Chao

2018-04-14

Understanding the heterogeneous evolution characteristics of dissolved organic matter fractions derived from compost is crucial to exploring the composting biodegradation process and the possible applications of compost products. Herein, two-dimensional correlation spectroscopy integrated with reversed-phase high performance liquid chromatography and size exclusion chromatography were utilized to obtain the molecular weight (MW) and polarity evolution characteristics of humic acid (HA), fulvic acid (FA), and the hydrophilic (HyI) fractions during composting. The high-MW humic substances and building blocks in the HA fraction degraded faster during composting than polymers, proteins, and organic colloids. Similarly, the low MW acid FA factions transformed faster than the low weight neutral fractions, followed by building blocks, and finally polymers, proteins, and organic colloids. The evolutions of HyI fractions during composting occurred first for building blocks, followed by low MW acids, and finally low weight neutrals. With the progress of composting, the hydrophobic properties of the HA and FA fractions were enhanced. The degradation/humification process of the hydrophilic and transphilic components was faster than that of the hydrophobic component. Compared with the FA and HyI fractions, the HA fraction exhibited a higher MW and increased hydrophobicity. Copyright © 2018 Elsevier B.V. All rights reserved.

N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thorn, Kevin A.; Cox, Larry G.

2009-02-28

The naturally abundant nitrogen in soil and aquatic NOM samples from the International Humic Substances Society has been characterized by solid state CP/MAS ¹⁵N NMR. Soil samples include humic and fulvic acids from the Elliot soil, Minnesota Waskish peat and Florida Pahokee peat, as well as the Summit Hill soil humic acid and the Leonardite humic acid. Aquatic samples include Suwannee River humic, fulvic and reverse osmosis isolates, Nordic humic and fulvic acids and Pony Lake fulvic acid. Additionally, Nordic and Suwannee River XAD-4 acids and Suwannee River hydrophobic neutral fractions were analyzed. Similar to literature reports, amide/aminoquinone nitrogens comprisedmore » the major peaks in the solid state spectra of the soil humic and fulvic acids, along with heterocyclic and amino sugar/terminal amino acid nitrogens. Spectra of aquatic samples, including the XAD-4 acids, contain resolved heterocyclic nitrogen peaks in addition to the amide nitrogens. The spectrum of the nitrogen enriched, microbially derived Pony Lake, Antarctica fulvic acid, appeared to contain resonances in the region of pyrazine, imine and/or pyridine nitrogens, which have not been observed previously in soil or aquatic humic substances by ¹⁵N NMR. Liquid state ¹⁵N NMR experiments were also recorded on the Elliot soil humic acid and Pony Lake fulvic acid, both to examine the feasibility of the techniques, and to determine whether improvements in resolution over the solid state could be realized. For both samples, polarization transfer (DEPT) and indirect detection (¹H–¹⁵N gHSQC) spectra revealed greater resolution among nitrogens directly bonded to protons. The amide/aminoquinone nitrogens could also be observed by direct detection experiments.« less

Fungal treatment of humic-rich industrial wastewater: application of white rot fungi in remediation of food-processing wastewater.

PubMed

Zahmatkesh, Mostafa; Spanjers, Henri; van Lier, Jules B

2017-11-01

This paper presents the results of fungal treatment of a real industrial wastewater (WW), providing insight into the main mechanisms involved and clarifying some ambiguities and uncertainties in the previous reports. In this regard, the mycoremediation potentials of four strains of white rot fungi (WRF): Phanerochaete chrysosporium, Trametes versicolor, Pleurotus ostreatus and Pleurotus pulmonarius were tested to remove humic acids (HA) from a real humic-rich industrial treated WW of a food-processing plant. The HA removal was assessed by color measurement and size-exclusion chromatography (SEC) analysis. T. versicolor showed the best decolorization efficiency of 90% and yielded more than 45% degradation of HA, which was the highest among the tested fungal strains. The nitrogen limitation was studied and results showed that it affected the fungal extracellular laccase and manganese peroxidase (MnP) activities. The results of the SEC analysis revealed that the mechanism of HA removal by WRF involves degradation of large HA molecules to smaller molecules, conversion of HA to fulvic acid-like molecules and also biosorption of HA by fungal mycelia. The effect of HS on the growth of WRF was investigated and results showed that the inhibition or stimulation of growth differs among the fungal strains.

Order of functionality loss during photodegradation of aquatic humic substances

USGS Publications Warehouse

Thorn, Kevin A.; Younger, Steven J.; Cox, Larry G.

2009-01-01

The time course photodegradation of the Nordic aquatic fulvic and humic acids and Suwannee River XAD-4 acids subjected to UV irradiation with an unfiltered medium pressure mercury lamp was studied by liquid-state 13C nuclear magnetic resonance. Photodecarboxylation was a significant pathway in all cases. Decreases in ketone, aromatic, and O-alkyl carbons were observed throughout the course of the irradiations, whereas C-alkyl carbons resisted photodegradation. Peaks attributable to the low-molecular-weight photodegradation products bicarbonate, formate, acetate, and succinate grew in intensity with irradiation time. The final products of the irradiations were decarboxylated, hydrophobic, predominantly C-alkyl and O-alkyl materials that were resistant to further photodegradation. The total amount of carbon susceptible to loss appeared to be related mainly to the total concentration of carbonyl and aromatic carbons and partly to the concentration of O-alkyl carbons in the fulvic, humic, and XAD-4 acids. The carbon losses for Nordic fulvic, Nordic Humic, Suwannee fulvic, and Suwannee XAD-4 acids were estimated to be 75, 63, 56, and 17%, respectively. More detailed analyses of the effects of irradiation on the carbonyl functionality in Nordic humic acid and Laurentian soil fulvic acid through reaction with hydroxylamine in conjunction with 15N nuclear magnetic resonance analysis confirmed preferential photodegradation of the quinone/hydroquinone functionality over ketone groups and the loss of ester groups in Laurentian fulvic acid.

The Polyphenol Chlorogenic Acid Attenuates UVB-mediated Oxidative Stress in Human HaCaT Keratinocytes

PubMed Central

Cha, Ji Won; Piao, Mei Jing; Kim, Ki Cheon; Yao, Cheng Wen; Zheng, Jian; Kim, Seong Min; Hyun, Chang Lim; Ahn, Yong Seok; Hyun, Jin Won

2014-01-01

We investigated the protective effects of chlorogenic acid (CGA), a polyphenol compound, on oxidative damage induced by UVB exposure on human HaCaT cells. In a cell-free system, CGA scavenged 1,1-diphenyl-2-picrylhydrazyl radicals, superoxide anions, hydroxyl radicals, and intracellular reactive oxygen species (ROS) generated by hydrogen peroxide and ultraviolet B (UVB). Furthermore, CGA absorbed electromagnetic radiation in the UVB range (280–320 nm). UVB exposure resulted in damage to cellular DNA, as demonstrated in a comet assay; pre-treatment of cells with CGA prior to UVB irradiation prevented DNA damage and increased cell viability. Furthermore, CGA pre-treatment prevented or ameliorated apoptosis-related changes in UVB-exposed cells, including the formation of apoptotic bodies, disruption of mitochondrial membrane potential, and alterations in the levels of the apoptosis-related proteins Bcl-2, Bax, and caspase-3. Our findings suggest that CGA protects cells from oxidative stress induced by UVB radiation. PMID:24753819

Two Cytoplasmic Acylation Sites and an Adjacent Hydrophobic Residue, but No Other Conserved Amino Acids in the Cytoplasmic Tail of HA from Influenza A Virus Are Crucial for Virus Replication

PubMed Central

Siche, Stefanie; Brett, Katharina; Möller, Lars; Kordyukova, Larisa V.; Mintaev, Ramil R.; Alexeevski, Andrei V.; Veit, Michael

2015-01-01

Recruitment of the matrix protein M1 to the assembly site of the influenza virus is thought to be mediated by interactions with the cytoplasmic tail of hemagglutinin (HA). Based on a comprehensive sequence comparison of all sequences present in the database, we analyzed the effect of mutating conserved residues in the cytosol-facing part of the transmembrane region and cytoplasmic tail of HA (A/WSN/33 (H1N1) strain) on virus replication and morphology of virions. Removal of the two cytoplasmic acylation sites and substitution of a neighboring isoleucine by glutamine prevented rescue of infectious virions. In contrast, a conservative exchange of the same isoleucine, non-conservative exchanges of glycine and glutamine, deletion of the acylation site at the end of the transmembrane region and shifting it into the tail did not affect virus morphology and had only subtle effects on virus growth and on the incorporation of M1 and Ribo-Nucleoprotein Particles (RNPs). Thus, assuming that essential amino acids are conserved between HA subtypes we suggest that, besides the two cytoplasmic acylation sites (including adjacent hydrophobic residues), no other amino acids in the cytoplasmic tail of HA are indispensable for virus assembly and budding. PMID:26670246

Silver(I) Binding Properties of Organic Soil Materials Are Different from Those of Isolated Humic Substances.

PubMed

B Kleja, Dan; Nakata, Satomi; Persson, Ingmar; Gustafsson, Jon Petter

2016-07-19

The solubility of silver(I) in many soils is controlled by complexation reactions with organic matter. In this work we have compared the ability of isolated humic and fulvic acids to bind silver(I) with that of mor and peat materials. One new data set for Suwannee River Fulvic Acid was produced, which was consistent with published data sets for isolated fulvic and humic acids. The ability of soil materials to bind silver(I) was studied as a function of pH in the range 2.5-5.0, at a wide range of silver(I)-to-soil ratios (10(-4.2) - 10(-1.9) mol kg(-1)). By calibrating the Stockholm Humic Model on the humic and fulvic acids data sets, we showed that binding of silver(I) to both types of soil materials was much stronger (up to 2 orders of magnitude) than predicted from the silver(I) binding properties of the isolated humic materials. Thus, the approach taken for many other metals, that is, to model solubility in soils by using metal and proton binding parameters derived from isolated humic and fulvic acids, cannot be used for silver(I). One possible explanation for the discrepancy could be that silver(I) predominately interacted with various biomolecules in the soil samples, instead of humic- and fulvic-acid type materials.

Chemical characteristics of particulate, colloidal, and dissolved organic material in Loch Vale Watershed, Rocky Mountain National Park

USGS Publications Warehouse

McKnight, Diane M.; Harnish, R.; Wershaw, R. L.; Baron, Jill S.; Schiff, S.

1997-01-01

The chemical relationships among particulate and colloidal organic material and dissolved fulvic acid were examined in an alpine and subalpine lake and two streams in Loch Vale Watershed, Rocky Mountain National Park. The alpine lake, Sky Pond, had the lowest dissolved organic carbon (DOC) (0.37 mgC/L), the highest particulate carbon (POC) (0.13 mgC/L), and high algal biomass. The watershed of Sky Pond is primarily talus slope, and DOC and POC may be autochthonous. Both Andrews Creek and Icy Brook gain DOC as they flow through wet sedge meadows. The subalpine lake, The Loch, receives additional organic material from the surrounding forest and had a higher DOC (0.66 mgC/L). Elemental analysis, stable carbon isotopic compositon, and 13C-NMR characterization showed that: 1) particulate material had relatively high inorganic contents and was heterogeneous in compositon, 2) colloidal material was primarily carbohydrate material with a low inorganic content at all sites; and 3) dissolved fulvic acid varied in compositon among sites. The low concentration and carbohydrate-rich character of the colloidal material suggests that this fraction is labile to microbial degradation and may be turning over more rapidly than particulate fractions or dissolved fulvic acid. Fulvic acid from Andrews Creek had the lowest N content and aromaticity, whereas Sky Pond fulvic acid had a higher N content and lower aromaticity than fulvic acid from The Loch. The UV-visible spectra of the fulvic acids demonstrate that variation in characteristics with sources of organic carbon can explain to some extent the observed nonlinear relationship between UV-B extinction coefficients and DOC concentrations in lakes.

Reversible Association of the Hemagglutinin Subcomplex, HA-33/HA-17 Trimer, with the Botulinum Toxin Complex.

PubMed

Sagane, Yoshimasa; Mutoh, Shingo; Koizumi, Ryosuke; Suzuki, Tomonori; Miyashita, Shin-Ichiro; Miyata, Keita; Ohyama, Tohru; Niwa, Koichi; Watanabe, Toshihiro

2017-10-01

Botulinum neurotoxin (BoNT) associates with nontoxic proteins, either a nontoxic nonhemagglutinin (NTNHA) or the complex of NTNHA and hemagglutinin (HA), to form M- or L-toxin complexes (TCs). Single BoNT and NTNHA molecules are associated and form M-TC. A trimer of the 70-kDa HA protein (HA-70) attaches to the M-TC to form M-TC/HA-70. Further, 1-3 arm-like 33- and 17-kDa HA molecules (HA-33/HA-17 trimer), consisting of 1 HA-17 protein and 2 HA-33 proteins, can attach to the M-TC/HA-70 complex, yielding 1-, 2-, and 3-arm L-TC. In this study, the purified 1- and 2-arm L-TCs spontaneously converted into another L-TC species after acquiring the HA-33/HA-17 trimer from other TCs during long-term storage and freezing/thawing. Transmission electron microscopy analysis provided evidence of the formation of detached HA-33/HA-17 trimers in the purified TC preparation. These findings provide evidence of reversible association/dissociation of the M-TC/HA-70 complex with the HA-33/HA-17 trimers, as well as dynamic conversion of the quaternary structure of botulinum TC in culture.

Secondary anchor polymorphism in the HA-1 minor histocompatibility antigen critically affects MHC stability and TCR recognition

PubMed Central

Nicholls, Sarah; Piper, Karen P.; Mohammed, Fiyaz; Dafforn, Timothy R.; Tenzer, Stefan; Salim, Mahboob; Mahendra, Premini; Craddock, Charles; van Endert, Peter; Schild, Hansjörg; Cobbold, Mark; Engelhard, Victor H.; Moss, Paul A. H.; Willcox, Benjamin E.

2009-01-01

T cell recognition of minor histocompatibility antigens (mHags) underlies allogeneic immune responses that mediate graft-versus-host disease and the graft-versus-leukemia effect following stem cell transplantation. Many mHags derive from single amino acid polymorphisms in MHC-restricted epitopes, but our understanding of the molecular mechanisms governing mHag immunogenicity and recognition is incomplete. Here we examined antigenic presentation and T-cell recognition of HA-1, a prototypic autosomal mHag derived from single nucleotide dimorphism (HA-1H versus HA-1R) in the HMHA1 gene. The HA-1H peptide is restricted by HLA-A2 and is immunogenic in HA-1R/R into HA-1H transplants, while HA-1R has been suggested to be a “null allele” in terms of T cell reactivity. We found that proteasomal cleavage and TAP transport of the 2 peptides is similar and that both variants can bind to MHC. However, the His>Arg change substantially decreases the stability and affinity of HLA-A2 association, consistent with the reduced immunogenicity of the HA-1R variant. To understand these findings, we determined the structure of an HLA-A2-HA-1H complex to 1.3Å resolution. Whereas His-3 is accommodated comfortably in the D pocket, incorporation of the lengthy Arg-3 is predicted to require local conformational changes. Moreover, a soluble TCR generated from HA-1H-specific T-cells bound HA-1H peptide with moderate affinity but failed to bind HA-1R, indicating complete discrimination of HA-1 variants at the level of TCR/MHC interaction. Our results define the molecular mechanisms governing immunogenicity of HA-1, and highlight how single amino acid polymorphisms in mHags can critically affect both MHC association and TCR recognition. PMID:19234124

Retention of Human-Induced Pluripotent Stem Cells (hiPS) With Injectable HA Hydrogels for Vocal Fold Engineering.

PubMed

Imaizumi, Mitsuyoshi; Li-Jessen, Nicole Y K; Sato, Yuka; Yang, David T; Thibeault, Susan L

2017-04-01

One prospective treatment option for vocal fold scarring is regeneration with an engineered scaffold containing induced pluripotent stem cells (iPS). In the present study, we investigated the feasibility of utilizing an injectable hyaluronic acid (HA) scaffold encapsulated with human-iPS cell (hiPS) for regeneration of vocal folds. Thirty athymic nude rats underwent unilateral vocal fold injury. Contralateral vocal folds served as uninjured controls. Hyaluronic acid hydrogel scaffold, HA hydrogel scaffold containing hiPS, and HA hydrogel scaffold containing hiPS with epidermal growth factor (EGF) were injected in both vocal folds immediately after surgery. One and 2 weeks after injection, larynges were excised for histology, immunohistochemistry, and fluorescence in situ hybridization (FISH). Presence of HA hydrogel was confirmed in vocal folds 1 and 2 weeks post injection. The FISH analysis confirmed the presence and viability of hiPS in the injected vocal folds. Histological results demonstrated that vocal folds injected with HA hydrogel scaffold containing EGF demonstrated less fibrosis than those with HA hydrogel only. Human-iPS survived in injured rat vocal folds. The HA hydrogel with hiPS and EGF ameliorated the fibrotic response. Additional work is necessary to optimize hiPS differentiation and further confirm the safety of hiPS for clinical applications.

An interpenetrating HA/G/CS biomimic hydrogel via Diels-Alder click chemistry for cartilage tissue engineering.

PubMed

Yu, Feng; Cao, Xiaodong; Zeng, Lei; Zhang, Qing; Chen, Xiaofeng

2013-08-14

In order to mimic the natural cartilage extracellular matrix, a novel biological degradable interpenetrating network hydrogel was synthesized from the gelatin (G), hyaluronic acid (HA) and chondroitin sulfate (CS) by Diels-Alder "click" chemistry. HA was modified with furylamine and G was modified with furancarboxylic acid respectively. (1)H NMR spectra and elemental analysis showed that the substitution degrees of HA-furan and G-furan were 71.5% and 44.5%. Then the hydrogels were finally synthesized by cross-linking furan-modified HA and G derivatives with dimaleimide poly(ethylene glycol) (MAL-PEG-MAL). The mechanical and degradation properties of the hydrogels could be tuned simply through varying the molar ratio between furan and maleimide. Rheological, mechanical and degradation studies demonstrated that the Diels-Alder "click" chemistry is an efficient method for preparing high performance biological interpenetrating hydrogels. This biomimic hydrogel with improved mechanical properties could have great potential applications in cartilage tissue engineering. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pyrolysis-mass spectrometry/pattern recognition on a well-characterized suite of humic samples

USGS Publications Warehouse

MacCarthy, P.; DeLuca, S.J.; Voorhees, K.J.; Malcolm, R.L.; Thurman, E.M.

1985-01-01

A suite of well-characterized humic and fulvic acids of freshwater, soil and plant origin was subjected to pyrolysis-mass spectrometry and the resulting data were analyzed by pattern recognition and factor analysis. A factor analysis plot of the data shows that the humic acids and fulvic acids can be segregated into two distinct classes. Carbohydrate and phenolic components are more pronounced in the pyrolysis products of the fulvic acids, and saturated and unsaturated hydrocarbons contribute more to the humic acid pyrolysis products. A second factor analysis plot shows a separation which appears to be based primarily on whether the samples are of aquatic or soil origin. ?? 1985.

Photoproduction of hydrogen peroxide in aqueous solution from model compounds for chromophoric dissolved organic matter (CDOM).

PubMed

Clark, Catherine D; de Bruyn, Warren; Jones, Joshua G

2014-02-15

To explore whether quinone moieties are important in chromophoric dissolved organic matter (CDOM) photochemistry in natural waters, hydrogen peroxide (H2O2) production and associated optical property changes were measured in aqueous solutions irradiated with a Xenon lamp for CDOM model compounds (dihydroquinone, benzoquinone, anthraquinone, napthoquinone, ubiquinone, humic acid HA, fulvic acid FA). All compounds produced H2O2 with concentrations ranging from 15 to 500 μM. Production rates were higher for HA vs. FA (1.32 vs. 0.176 mM h(-1)); values ranged from 6.99 to 0.137 mM h(-1) for quinones. Apparent quantum yields (Θ app; measure of photochemical production efficiency) were higher for HA vs. FA (0.113 vs. 0.016) and ranged from 0.0018 to 0.083 for quinones. Dihydroquinone, the reduced form of benzoquinone, had a higher production rate and efficiency than its oxidized form. Post-irradiation, quinone compounds had absorption spectra similar to HA and FA and 3D-excitation-emission matrix fluorescence spectra (EEMs) with fluorescent peaks in regions associated with CDOM. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical characteristics and acidity of soluble organic substances from a northern hardwood forest floor, central Maine, USA

NASA Astrophysics Data System (ADS)

Vance, George F.; David, Mark B.

1991-12-01

Our understanding of the chemistry, structure, and reactions of organic substances in forest floor leachates is limited and incomplete. Therefore, we examined the organic and inorganic chemistry of forest floor leachates collected from a hardwood forest in central Maine over a two-year period (1987-1989), including detailed study of dissolved organic carbon (DOC). Seasonal variations in NH 4+, NO 3-, K +, and total Al were believed due to organic matter decomposition and release. Leaching of other base cations closely followed that of NO 3-. Snowmelt resulted in NO 3- levels that decreased in time due to flushing of mineralization/nitrification by-products that had accumulated during the winter months. Total DOC ranged from 2228 to 7193 μmol L -1 with an average of 4835 μmol L -1. Monosaccharides and polyphenols constituted 3.9% (range of 3.4 to 4.4%) and 3.0% (2.2 to 3.7%) of the DOC, respectively, which suggests DOC may contain partially oxidized products that are possibly of a lignocellulose nature. Fractionation of the forest floor DOC indicated high organic acid contents (hydrophobic and hydrophilic acids) that averaged 92% of the total DOC. Organic acids were isolated and analyzed for elemental content (C, H, N, and S), and determination of UV absorptivity ( E 4/E 6) ratios, CuO oxidation products, FT-IR and 13C-NMR spectra, and acidity by potentiometric titration. Results from these analyses indicate the organic acids in the forest floor leachates are similar to fulvic acids. Hydrophobic and hydrophilic acids had average exchange acidities of 0.126 and 0.148 μeq μmol -1 C, respectively, and pKa, of 4.23 and 4.33. Their FT-IR and 13C-NMR spectra suggest they are primarily carboxylic acids, with aliphatic and aromatic structure. An organic charge contribution model was developed using titration data, DOC fractionation percentages, and the total DOC in the forest floor leachates. Application of the model to all solutions accounted for 97% of the charge

Chemistry and potential mutagenicity of humic substances in waters from different watersheds in Britain and Ireland

USGS Publications Warehouse

Watt, B.E.; Malcolm, R.L.; Hayes, M.H.B.; Clark, N.W.E.; Chipman, J.K.

1996-01-01

Humic substances are amorphous organic macromolecules responsible for the hue of natural waters. They are also known to be precursors of mutagens formed on chlorination prior to distribution of drinking water. In this study humic substances from the waters of primary streams, from major rivers, and from reservoirs were isolated and fractionated into humic acids (HA), fulvic acids (FA) and XAD-4 acids using columns of XAD-8 and of XAD-4 resins in tandem, and the fractions from the different sources were chlorinated and assayed for mutagenicity. CPMAS 13C NMR spectroscopy showed marked differences in compositions not only between HA, FA, and XAD-4 acids from the same water samples, but also between the same fractions from water samples from different watersheds. There were found to be strong similarities between the fractions from watersheds which had closely related soil types. Aromaticity was greatest in HAs, and lowest in XAD-4 acids, and carboxyl contents and aliphatic character were greatest in the XAD-4 acids. Carbon content decreased in the order HA > FA > XAD-4 acids, and amino acids and neutral sugars contents decreased in the order HA > XAD-4 > FA. Titration data complemented aspects of the NMR data, demonstrating that carboxyl content decreased in the order XAD-4 acids > FA > HA, and indicated that phenolic character was highest in HAs and lowest in the XAD-4 acids. All samples tested gave rise to bacterial mutagens on chlorination. Although the mutagenicities were of the same order of magnitude for the chlorinated humic samples from the different sources, the samples which showed the greatest number of revertant bacterial colonies were from the Thames and Trent, large rivers with humic materials from diverse environments, and relatively high in amino acid contents.

The optimal SAM surface functional group for producing a biomimetic HA coating on Ti.

PubMed

Liu, D P; Majewski, P; O'Neill, B K; Ngothai, Y; Colby, C B

2006-06-15

Commercial interest is growing in biomimetic methods that employ self assembled mono-layers (SAMs) to produce biocompatible HA coatings on Ti-based orthopedic implants. Recently, separate studies have considered HA formation for various SAM surface functional groups. However, these have often neglected to verify crystallinity of the HA coating, which is essential for optimal bioactivity. Furthermore, differing experimental and analytical methods make performance comparisons difficult. This article investigates and evaluates HA formation for four of the most promising surface functional groups: --OH, --SO(3)H, --PO(4)H(2) and --COOH. All of them successfully formed a HA coating at Ca/P ratios between 1.49 and 1.62. However, only the --SO(3)H and --COOH end groups produced a predominantly crystalline HA. Furthermore, the --COOH end group yielded the thickest layer and possessed crystalline characteristics very similar to that of the human bone. The --COOH end group appears to provide the optimal SAM surface interface for nucleation and growth of biomimetic crystalline HA. Intriguingly, this finding may lend support to explanations elsewhere of why human bone sialoprotein is such a potent nucleator of HA and is attributed to the protein's glutamic acid-rich sequences.

ω-Oxidation of α-Chlorinated Fatty Acids

PubMed Central

Brahmbhatt, Viral V.; Albert, Carolyn J.; Anbukumar, Dhanalakshmi S.; Cunningham, Bryce A.; Neumann, William L.; Ford, David A.

2010-01-01

Myeloperoxidase-derived HOCl targets tissue- and lipoprotein-associated plasmalogens to generate α-chlorinated fatty aldehydes, including 2-chlorohexadecanal. Under physiological conditions, 2-chlorohexadecanal is oxidized to 2-chlorohexadecanoic acid (2-ClHA). This study demonstrates the catabolism of 2-ClHA by ω-oxidation and subsequent β-oxidation from the ω-end. Mass spectrometric analyses revealed that 2-ClHA is ω-oxidized in the presence of liver microsomes with initial ω-hydroxylation of 2-ClHA. Subsequent oxidation steps were examined in a human hepatocellular cell line (HepG2). Three different α-chlorinated dicarboxylic acids, 2-chlorohexadecane-(1,16)-dioic acid, 2-chlorotetradecane-(1,14)-dioic acid, and 2-chloroadipic acid (2-ClAdA), were identified. Levels of 2-chlorohexadecane-(1,16)-dioic acid, 2-chlorotetradecane-(1,14)-dioic acid, and 2-ClAdA produced by HepG2 cells were dependent on the concentration of 2-ClHA and the incubation time. Synthetic stable isotope-labeled 2-ClHA was used to demonstrate a precursor-product relationship between 2-ClHA and the α-chlorinated dicarboxylic acids. We also report the identification of endogenous 2-ClAdA in human and rat urine and elevations in stable isotope-labeled urinary 2-ClAdA in rats subjected to intraperitoneal administration of stable isotope-labeled 2-ClHA. Furthermore, urinary 2-ClAdA and plasma 2-ClHA levels are increased in LPS-treated rats. Taken together, these data show that 2-ClHA is ω-oxidized to generate α-chlorinated dicarboxylic acids, which include α-chloroadipic acid that is excreted in the urine. PMID:20956542

Isolation, purification and analysis of dissolved organic carbon from Gohagoda uncontrolled open dumpsite leachate, Sri Lanka.

PubMed

Vithanage, Meththika; Wijesekara, Hasintha; Mayakaduwa, S S

2017-07-01

Extract and analysis of the Dissolved Organic Carbon (DOC) fractions were analyzed from the leachate of an uncontrolled dumpsite at Gohagoda, Sri Lanka. DOC fractions, humic acid (HA), fulvic acid (FA) and the hydrophilic (Hyd) fractions were isolated and purified with the resin techniques. Spectroscopic techniques and elemental analysis were performed to characterize DOCs. Maximum TOC and DOC values recorded were 56,955 and 28,493 mg/L, respectively. Based on the total amount of DOC fractionation, Hyd dominated accounting for ∼60%, and HA and FA constituted ∼22% and ∼17%, respectively, exhibiting the mature phase of the dumpsite. The elemental analysis of DOCs revealed carbon variation following HA > FA > Hyd, while hydrogen and nitrogen were similar in each fraction. The N/C ratio for HA was recorded as 0.18, following a similar trend in old dumpsite leachate elsewhere. The O/C ratios for HA and FA were recorded higher as much as 1.0 and 9.3, respectively, indicating high degree of carbon mineralization in the leachates. High content of carboxylic, phenolic and lactone groups in all DOCs was observed disclosing their potential for toxic substances transportation. The results strongly suggest the risk associated with DOCs in dumpsite leachate to the aquatic and terrestrial environment.

Cytotoxic agents for KB and SiHa cells from n-hexane fraction of Cissampelos pareira and its chemical composition.

PubMed

Bala, Manju; Pratap, Kunal; Verma, Praveen Kumar; Padwad, Yogendra; Singh, Bikram

2015-01-01

Eleven constituents were characterised by gas chromatography-mass spectrometry analysis, and five molecules were isolated using column chromatography. The in vitro study of the extract and isolated molecules against KB and SiHa cell lines revealed oleanolic acid (1) and oleic acid (2) as potent cytotoxic molecules with potential anticancer activity. The IC50 values of n-hexane extract (CPHF), oleanolic acid (1) and oleic acid (2) were >300, 56.08 and 70.7 μg/mL (μM), respectively, against KB cell lines and >300, 47.24 and 80.2 μg/mL (μM), respectively, against SiHa cell lines.

Understanding the undelaying mechanism of HA-subtyping in the level of physic-chemical characteristics of protein.

PubMed

Ebrahimi, Mansour; Aghagolzadeh, Parisa; Shamabadi, Narges; Tahmasebi, Ahmad; Alsharifi, Mohammed; Adelson, David L; Hemmatzadeh, Farhid; Ebrahimie, Esmaeil

2014-01-01

The evolution of the influenza A virus to increase its host range is a major concern worldwide. Molecular mechanisms of increasing host range are largely unknown. Influenza surface proteins play determining roles in reorganization of host-sialic acid receptors and host range. In an attempt to uncover the physic-chemical attributes which govern HA subtyping, we performed a large scale functional analysis of over 7000 sequences of 16 different HA subtypes. Large number (896) of physic-chemical protein characteristics were calculated for each HA sequence. Then, 10 different attribute weighting algorithms were used to find the key characteristics distinguishing HA subtypes. Furthermore, to discover machine leaning models which can predict HA subtypes, various Decision Tree, Support Vector Machine, Naïve Bayes, and Neural Network models were trained on calculated protein characteristics dataset as well as 10 trimmed datasets generated by attribute weighting algorithms. The prediction accuracies of the machine learning methods were evaluated by 10-fold cross validation. The results highlighted the frequency of Gln (selected by 80% of attribute weighting algorithms), percentage/frequency of Tyr, percentage of Cys, and frequencies of Try and Glu (selected by 70% of attribute weighting algorithms) as the key features that are associated with HA subtyping. Random Forest tree induction algorithm and RBF kernel function of SVM (scaled by grid search) showed high accuracy of 98% in clustering and predicting HA subtypes based on protein attributes. Decision tree models were successful in monitoring the short mutation/reassortment paths by which influenza virus can gain the key protein structure of another HA subtype and increase its host range in a short period of time with less energy consumption. Extracting and mining a large number of amino acid attributes of HA subtypes of influenza A virus through supervised algorithms represent a new avenue for understanding and

Understanding the Underlying Mechanism of HA-Subtyping in the Level of Physic-Chemical Characteristics of Protein

PubMed Central

Ebrahimi, Mansour; Aghagolzadeh, Parisa; Shamabadi, Narges; Tahmasebi, Ahmad; Alsharifi, Mohammed; Adelson, David L.

2014-01-01

The evolution of the influenza A virus to increase its host range is a major concern worldwide. Molecular mechanisms of increasing host range are largely unknown. Influenza surface proteins play determining roles in reorganization of host-sialic acid receptors and host range. In an attempt to uncover the physic-chemical attributes which govern HA subtyping, we performed a large scale functional analysis of over 7000 sequences of 16 different HA subtypes. Large number (896) of physic-chemical protein characteristics were calculated for each HA sequence. Then, 10 different attribute weighting algorithms were used to find the key characteristics distinguishing HA subtypes. Furthermore, to discover machine leaning models which can predict HA subtypes, various Decision Tree, Support Vector Machine, Naïve Bayes, and Neural Network models were trained on calculated protein characteristics dataset as well as 10 trimmed datasets generated by attribute weighting algorithms. The prediction accuracies of the machine learning methods were evaluated by 10-fold cross validation. The results highlighted the frequency of Gln (selected by 80% of attribute weighting algorithms), percentage/frequency of Tyr, percentage of Cys, and frequencies of Try and Glu (selected by 70% of attribute weighting algorithms) as the key features that are associated with HA subtyping. Random Forest tree induction algorithm and RBF kernel function of SVM (scaled by grid search) showed high accuracy of 98% in clustering and predicting HA subtypes based on protein attributes. Decision tree models were successful in monitoring the short mutation/reassortment paths by which influenza virus can gain the key protein structure of another HA subtype and increase its host range in a short period of time with less energy consumption. Extracting and mining a large number of amino acid attributes of HA subtypes of influenza A virus through supervised algorithms represent a new avenue for understanding and

Randomized clinical trial between polyacrylate-polyalcohol copolymer (PPC) and dextranomer-hyaluronic acid copolymer (Dx/HA) as bulking agents for endoscopic treatment of primary vesicoureteral reflux (VUR).

PubMed

García-Aparicio, L; Blázquez-Gómez, E; Martin, O; Pérez-Bertólez, S; Arboleda, J; Soria, A; Tarrado, X

2018-05-03

To compare the radiological and clinical outcomes of endoscopic treatment of primary VUR using polyacrylate-polyalcohol copolymer (PPC-Vantris ® ) or dextranomer-hyaluronic acid copolymer (Dx/HA-Deflux ® ). From October 2014 to April 2017, patients with primary VUR grade III to V that needed endoscopic treatment (ET) were eligible for this randomized clinical trial. We excluded toilet-trained patients with lower urinary tract symptoms. Patients were randomized and allocated into two groups: PPC group and Dx/HA group. After endoscopic treatment a voiding cystourethrography (VCUG) was performed at 6 months; if VUR was still present a second ET was performed. Radiological success was considered if postoperative VUR grade was 0 and clinical success rate was considered if no more fUTI appeared during follow-up. Forty-six patients were eligible but 2 did not accept the trial. Forty-four patients with 73 refluxing ureters were included. PPC: 34 refluxing ureters; and Dx/HA: 39 refluxing ureters. Both groups were statistically homogeneous and comparable. Mean follow-up was 27.6 months. Radiological success rate (82.2%) and clinical success rate (92.3%) were similar in both groups (p > 0.05). The volume of bulking agent used in those successfully treated was greater in Dx/HA group (p < 0.05). Distal ureter was excise in all cases of ureteral reimplantation after PPC treatment; however, distal ureter was preserved in all ureters reimplanted after Dx/HA injection. PPC and Dx/HA had similar outcomes, but we must warn that ureteral reimplantation after endoscopic treatment with PPC is difficult because of the periureteral fibrosis.

Relationship between organic matter humification and bioavailability of sludge-borne copper and cadmium during long-term sludge amendment to soil.

PubMed

Liu, Hongtao

2016-10-01

Recycling of sludge as soil amendment poses certain risk of heavy metals contamination. This study investigated the relationship between organic matter in composted sludge and its heavy metals bioavailability over 7years. Periodic monitoring indicated a gradual increase in organic matter degradation, accompanied by changing degrees of polymerization, i.e., ratio of humic acid (HA)/fulvic acid (FA) coupled with incremental exchangeable fraction of copper (Cu) in sludge, with a growing rate of 74.7%, rather than that in soil. However, cadmium (Cd) in composted sludge exhibited an independent manner. Linear-regression analysis revealed that the total proportion of the Cu active fraction (exchangeable plus carbonate bound) was better correlated with the degree of polymerization (DP) and humification ratio (HR) than the degradation ratio of organic matter. Overall, amount of uptaken Cu was more dependent on the humification degree of organic matter, especially the proportion of HA in humus. Copyright © 2016 Elsevier B.V. All rights reserved.

Liver-targeting self-assembled hyaluronic acid-glycyrrhetinic acid micelles enhance hepato-protective effect of silybin after oral administration.

PubMed

Han, Xiaofeng; Wang, Zhe; Wang, Manyuan; Li, Jing; Xu, Yongsong; He, Rui; Guan, Hongyu; Yue, Zhujun; Gong, Muxin

2016-06-01

In order to enhance oral bioavailability and liver targeting delivery of silybin, two amphiphilic hyaluronic acid derivatives, hyaluronic acid-deoxycholic acid (HA-adh-DOCA) and hyaluronic acid-glycyrrhetinic acid (HA-adh-GA) conjugates, were designed and synthesized. Silybin was successfully loaded in HA-adh-DOCA and HA-adh-GA micelles with high drug-loading capacities (20.3% ± 0.5% and 20.6% ± 0.6%, respectively). The silybin-loaded micelles were spherical in shape with the average size around 130 nm. In vitro release study showed that two silybin-loaded micelles displayed similar steady continued-release pattern in simulated gastrointestinal fluids and PBS. Single-pass intestinal perfusion studies indicated that silybin-loaded micelles were absorbed in the whole intestine and transported via a passive diffusion mechanism. Compared with suspension formulation, silybin-loaded HA-adh-DOCA and HA-adh-GA micelles achieved significantly higher AUC and Cmax level. Moreover, liver targeting drug delivery of micelles was confirmed by in vivo imaging analysis. In comparison between the two micellar formulations, HA-adh-GA micelles possessed higher targeting capacity than HA-adh-DOCA micelles, owing to the active hepatic targeting properties of glycyrrhetinic acid. In the treatment of acute liver injury induced by CCl4, silybin-loaded HA-adh-GA micelles displayed better effects over suspension control and silybin-loaded HA-adh-DOCA micelles. Overall, pharmaceutical and pharmacological indicators suggested that the HA-adh-GA conjugates can be successfully utilized for liver targeting of orally administered therapeutics.

Number of independent parameters in the potentiometric titration of humic substances.

PubMed

Lenoir, Thomas; Manceau, Alain

2010-03-16

With the advent of high-precision automatic titrators operating in pH stat mode, measuring the mass balance of protons in solid-solution mixtures against the pH of natural and synthetic polyelectrolytes is now routine. However, titration curves of complex molecules typically lack obvious inflection points, which complicates their analysis despite the high-precision measurements. The calculation of site densities and median proton affinity constants (pK) from such data can lead to considerable covariance between fit parameters. Knowing the number of independent parameters that can be freely varied during the least-squares minimization of a model fit to titration data is necessary to improve the model's applicability. This number was calculated for natural organic matter by applying principal component analysis (PCA) to a reference data set of 47 independent titration curves from fulvic and humic acids measured at I = 0.1 M. The complete data set was reconstructed statistically from pH 3.5 to 9.8 with only six parameters, compared to seven or eight generally adjusted with common semi-empirical speciation models for organic matter, and explains correlations that occur with the higher number of parameters. Existing proton-binding models are not necessarily overparametrized, but instead titration data lack the sensitivity needed to quantify the full set of binding properties of humic materials. Model-independent conditional pK values can be obtained directly from the derivative of titration data, and this approach is the most conservative. The apparent proton-binding constants of the 23 fulvic acids (FA) and 24 humic acids (HA) derived from a high-quality polynomial parametrization of the data set are pK(H,COOH)(FA) = 4.18 +/- 0.21, pK(H,Ph-OH)(FA) = 9.29 +/- 0.33, pK(H,COOH)(HA) = 4.49 +/- 0.18, and pK(H,Ph-OH)(HA) = 9.29 +/- 0.38. Their values at other ionic strengths are more reliably calculated with the empirical Davies equation than any existing model fit.

Influence of preozonation on the adsorptivity of humic substances onto activated carbon.

PubMed

Rodríguez, Francisco J; García-Valverde, María

2016-11-01

This research aims to study the influence of preozonation on the adsorptivity of humic substances onto activated carbon, which are usual stages in drinking water treatment. Three different types of humic substances were used in this study: natural fulvic and humic acids extracted from the Úzquiza Reservoir (Burgos, Spain) and a commercially supplied humic acid. The fractionation of the humic substances by ultrafiltration showed a very different molecular weight (MW) distribution for them: the lowest fraction of <1 kDa comprises the vast majority of the fulvic acids (around 86 %), whereas the main fraction for the commercial humic acids was the highest one of >30 kDa (around 40 %). The natural humic acids show an intermediate distribution between the two aforementioned humic substances. The 1-5-kDa fraction turned out to be the most reactive toward trihalomethane formation for the commercial humic acids. The adsorptive capacity of activated carbon for the humic substances was in the following order: natural fulvic acids > natural humic acids > commercial humic acids. The most adsorbable fraction was that of <1 kDa for the fulvic acids, whereas the 5-10-kDa fraction was the most adsorbable for both humic acids. Preozonation changes the MW distribution of the humic substances, decreasing the abundance of the high MW fractions and generating smaller molecules within the low to medium MW range. Adsorption isotherms show that preozonation has a beneficial effect on the adsorptivity of the commercial humic acids onto activated carbon, whereas no appreciable effect was observed for the case of the fulvic acids.

The uniqueness of humic substances in each of soil, stream and marine environments

USGS Publications Warehouse

Malcolm, R.L.

1990-01-01

Definitive compositional differences are shown to exist for both fulvic acids and humic acids from soil, stream and marine environments by five different methods (1H and 13C NMR spectroscopy, 14C age and ?? 13C isotopic analyses, amino acid analyses and pyrolysis-mass spectrometry). Definitive differences are also found between fulvic acids and humic acids within each environment. These differences among humic substances from various sources are more readily discerned because the method employed for the isolation of humic substances from all environments excludes most of the non-humic components and results in more purified humic isolates from water and soils. The major compositional aspects of fulvic acids and humic acids which determine the observed characteristic differences in each environment are the amounts and compositions of saccharide, phenolic, methoxyl, aromatic, hydrocarbon, amino acid and nitrogen moieties.

A Modified ELISA Accurately Measures Secretion of High Molecular Weight Hyaluronan (HA) by Graves' Disease Orbital Cells

PubMed Central

Krieger, Christine C.

2014-01-01

Excess production of hyaluronan (hyaluronic acid [HA]) in the retro-orbital space is a major component of Graves' ophthalmopathy, and regulation of HA production by orbital cells is a major research area. In most previous studies, HA was measured by ELISAs that used HA-binding proteins for detection and rooster comb HA as standards. We show that the binding efficiency of HA-binding protein in the ELISA is a function of HA polymer size. Using gel electrophoresis, we show that HA secreted from orbital cells is primarily comprised of polymers more than 500 000. We modified a commercially available ELISA by using 1 million molecular weight HA as standard to accurately measure HA of this size. We demonstrated that IL-1β-stimulated HA secretion is at least 2-fold greater than previously reported, and activation of the TSH receptor by an activating antibody M22 from a patient with Graves' disease led to more than 3-fold increase in HA production in both fibroblasts/preadipocytes and adipocytes. These effects were not consistently detected with the commercial ELISA using rooster comb HA as standard and suggest that fibroblasts/preadipocytes may play a more prominent role in HA remodeling in Graves' ophthalmopathy than previously appreciated. PMID:24302624

Influence of dissolved organic matter on photogenerated reactive oxygen species and metal-oxide nanoparticle toxicity.

PubMed

Li, Yang; Niu, Junfeng; Shang, Enxiang; Crittenden, John Charles

2016-07-01

The effect of humic acid (HA) or fulvic acid (FA) on reactive oxygen species (ROS) generation by six metal-oxide nanoparticles (NPs) and their toxicities toward Escherichia coli was investigated under UV irradiation. Dissolved organic matter (DOM) decreased OH generation by TiO2, ZnO, and Fe2O3, with FA inhibiting OH generation more than HA. The generated OH in NPs/DOM mixtures was higher than the measured concentrations because DOM consumes OH faster than its molecular probe. None of NPs/FA mixtures produced O2(-). The generated O2(-) concentrations in NPs/HA mixtures (except Fe2O3/HA) were higher than the sum of O2(-) concentrations that produced as NPs and HA were presented by themselves. Synergistic O2(-) generation in NPs/HA mixtures resulted from O2 reduction by electron transferred from photoionized HA to NPs. DOM increased (1)O2 generation by TiO2, CuO, CeO2, and SiO2, and FA promoted (1)O2 generation more than HA. Enhanced (1)O2 generation resulted from DOM sensitization of NPs. HA did not increase (1)O2 generation by ZnO and Fe2O3 primarily because released ions quenched (1)O2 precursor ((3)HA*). Linear correlation was developed between total ROS concentrations generated by NPs/DOM mixtures and bacterial survival rates (R(2) ≥ 0.80). The results implied the necessity of considering DOM when investigating the photoreactivity of NPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modulating protein adsorption onto hydroxyapatite particles using different amino acid treatments

PubMed Central

Lee, Wing-Hin; Loo, Ching-Yee; Van, Kim Linh; Zavgorodniy, Alexander V.; Rohanizadeh, Ramin

2012-01-01

Hydroxyapatite (HA) is a material of choice for bone grafts owing to its chemical and structural similarities to the mineral phase of hard tissues. The combination of osteogenic proteins with HA materials that carry and deliver the proteins to the bone-defective areas will accelerate bone regeneration. The study investigated the treatment of HA particles with different amino acids such as serine (Ser), asparagine (Asn), aspartic acid (Asp) and arginine (Arg) to enhance the adsorption ability of HA carrier for delivering therapeutic proteins to the body. The crystallinity of HA reduced when amino acids were added during HA preparation. Depending on the types of amino acid, the specific surface area of the amino acid-functionalized HA particles varied from 105 to 149 m2 g–1. Bovine serum albumin (BSA) and lysozyme were used as model proteins for adsorption study. The protein adsorption onto the surface of amino acid-functionalized HA depended on the polarities of HA particles, whereby, compared with lysozyme, BSA demonstrated higher affinity towards positively charged Arg-HA. Alternatively, the binding affinity of lysozyme onto the negatively charged Asp-HA was higher when compared with BSA. The BSA and lysozyme adsorptions onto the amino acid-functionalized HA fitted better into the Freundlich than Langmuir model. The amino acid-functionalized HA particles that had higher protein adsorption demonstrated a lower protein-release rate. PMID:21957116

Regulation of Hyaluronan (HA) Metabolism Mediated by HYBID (Hyaluronan-binding Protein Involved in HA Depolymerization, KIAA1199) and HA Synthases in Growth Factor-stimulated Fibroblasts.

PubMed

Nagaoka, Aya; Yoshida, Hiroyuki; Nakamura, Sachiko; Morikawa, Tomohiko; Kawabata, Keigo; Kobayashi, Masaki; Sakai, Shingo; Takahashi, Yoshito; Okada, Yasunori; Inoue, Shintaro

2015-12-25

Regulation of hyaluronan (HA) synthesis and degradation is essential to maintenance of extracellular matrix homeostasis. We recently reported that HYBID (HYaluronan-Binding protein Involved in hyaluronan Depolymerization), also called KIAA1199, plays a key role in HA depolymerization in skin and arthritic synovial fibroblasts. However, regulation of HA metabolism mediated by HYBID and HA synthases (HASs) under stimulation with growth factors remains obscure. Here we report that TGF-β1, basic FGF, EGF, and PDGF-BB commonly enhance total amount of HA in skin fibroblasts through up-regulation of HAS expression, but molecular size of newly produced HA is dependent on HYBID expression levels. Stimulation of HAS1/2 expression and suppression of HYBID expression by TGF-β1 were abrogated by blockade of the MAPK and/or Smad signaling and the PI3K-Akt signaling, respectively. In normal human skin, expression of the TGF-β1 receptors correlated positively with HAS2 expression and inversely with HYBID expression. On the other hand, TGF-β1 up-regulated HAS1/2 expression but exerted only a slight suppressive effect on HYBID expression in synovial fibroblasts from the patients with osteoarthritis or rheumatoid arthritis, resulting in the production of lower molecular weight HA compared with normal skin and synovial fibroblasts. These data demonstrate that although TGF-β1, basic FGF, EGF, and PDGF-BB enhance HA production in skin fibroblasts, TGF-β1 most efficiently contributes to production of high molecular weight HA by HAS up-regulation and HYBID down-regulation and suggests that inefficient down-regulation of HYBID by TGF-β1 in arthritic synovial fibroblasts may be linked to accumulation of depolymerized HA in synovial fluids in arthritis patients. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Sources and haloacetic acid/trihalomethane formation potentials of aquatic humic substances in the Wakarusa River and Clinton Lake near Lawrence, Kansas

USGS Publications Warehouse

Pomes, M.L.; Larive, C.K.; Thurman, E.M.; Green, W.R.; Orem, W.H.; Rostad, C.E.; Coplen, T.B.; Cutak, B.J.; Dixon, A.M.

2000-01-01

Gram quantities of aquatic humic substances (AHS) were extracted from the Wakarusa River-Clinton Lake Reservoir system, near Lawrence, KS, to support nuclear magnetic resonance (NMR) experimental studies, report concentrations of dissolved organic carbon (DOC) and AHS, define sources of the AHS, and determine if the AHS yield sufficient quantities of haloacetic acids (HAA5) and trihalomethanes (THM4) that exceed U.S. Environmental Protection Agency (EPA) Maximum Contaminant Levels (MCL) in drinking water. AHS from the Wakarusa River and Clinton Lake originated from riparian forest vegetation, reflected respective effects of soil organic matter and aquatic algal/bacterial sources, and bore evidence of biological degradation and photodegradation. AHS from the Wakarusa River showed the effect of terrestrial sources, whereas Clinton Lake humicacid also reflected aquatic algal/bacterial sources. Greater amounts of carbon attributable to tannin-derived chemical structures may correspond with higher HAA5 and THM4 yields for Clinton Lake fulvic acid. Prior to appreciable leaf-fall from deciduous trees, the combined (humic and fulvic acid) THM4 formation potentials for the Wakarusa River approached the proposed EPA THM4 Stage I MCL of 80 ??g/L, and the combined THM4 formation potential for Clinton Lake slightly exceeded the proposed THM4 Stage II MCL of 40 ??g/L. Finally, AHS from Clinton Lake could account for most (>70%) of the THM4 concentrations in finished water from the Clinton Lake Water Treatment Plant based on September 23, 1996, THM4 results.Gram quantities of aquatic humic substances (AHS) were extracted from the Wakarusa River-Clinton Lake Reservoir system, near Lawrence, KS, to support nuclear magnetic resonance (NMR) experimental studies, report concentrations of dissolved organic carbon (DOC) and AHS, define sources of the AHS, and determine if the AHS yield sufficient quantities of haloacetic acids (HAA5) and trihalomethanes (THM4) that exceed U

Minor histocompatibility antigen HA-1 and HA-2 polymorphisms in Taiwan: frequency and application in hematopoietic stem cell transplantation.

PubMed

Lio, Hoi-Yan; Tang, Jih-Luh; Wu, Jui; Wu, Shang-Ju; Lin, Chun-Ying; Yang, Ya-Chien

2010-09-01

Minor histocompatibility antigens influence the occurrence of graft-vs.-host disease and graft-vs.-leukemia effects after hematopoietic stem cell transplantation (HSCT). We determined the population frequencies of HA-1 and HA-2 alleles in Taiwan and exploited their potential applications in allogeneic HSCT. HA-1 and HA-2 were genotyped using polymerase chain reaction and restriction fragment length polymorphism in healthy controls (221 for HA-1 and 306 for HA-2) and HLA-matched donor-recipient sibling pairs with HSCT (92 for HA-1 and 38 for HA-2). The association of genetic polymorphisms with HSCT outcome was evaluated by univariate and multivariate analyses. The allele frequencies in controls were 35.3% and 64.7% for HA-1(H) and HA-1(R), and 89.0% and 11.0% for HA-2(V) and HA-2(M), respectively. HA-1 disparity was denoted in 16.3% of HLA-matched donor-recipient sibling pairs, while it was not associated with HSCT outcome. HA-2 disparity was not observed in the donor-recipient pairs studied. The possibilities of using HA-1 and HA-2 variabilities as molecular markers for hematopoietic chimerism after HSCT were 39.2% and 18.4%, respectively. Our data provide the information on allele and genotype frequencies of HA-1 and HA-2 in a Taiwanese population, and suggest that prospective genomic typing for HA-1 and HA-2 alleles of the donor and recipient could be a useful approach for molecular identification of hematopoietic chimerism after HSCT, rather than prognosis of clinical outcome.

Colloidal diatomite, radionickel, and humic substance interaction: a combined batch, XPS, and EXAFS investigation.

PubMed

Sheng, Guodong; Shen, Runpu; Dong, Huaping; Li, Yimin

2013-06-01

This work determined the influence of humic acid (HA) and fulvic acid (FA) on the interaction mechanism and microstructure of Ni(II) onto diatomite by using batch experiments, X-ray photoelectron spectroscopy (XPS), and extended X-ray absorption fine structure (EXAFS) methods. Macroscopic and spectroscopic experiments have been combined to see the evolution of the interaction mechanism and microstructure of Ni(II) in the presence of HA/FA as compared with that in the absence of HA/FA. The results indicated that the interaction of Ni(II) with diatomite presents the expected solution pH edge at 7.0, which is modified by addition of HA/FA. In the presence of HA/FA, the interaction of Ni(II) with diatomite increased below solution pH 7.0, while Ni(II) interaction decreased above solution pH 7.0. XPS analysis suggested that the enrichment of Ni(II) onto diatomite may be due to the formation of (≡SO)2Ni. EXAFS results showed that binary surface complexes and ternary surface complexes of Ni(II) can be simultaneously formed in the presence of HA/FA, whereas only binary surface complexes of Ni(II) are formed in the absence of HA/FA, which contribute to the enhanced Ni(II) uptake at low pH values. The results observed in this work are important for the evaluation of Ni(II) and related radionuclide physicochemical behavior in the natural soil and water environment.

Comparing humic substance and protein compound effects on the bioaccumulation of perfluoroalkyl substances by Daphnia magna in water.

PubMed

Xia, Xinghui; Dai, Zhineng; Rabearisoa, Andry Harinaina; Zhao, Pujun; Jiang, Xiaoman

2015-01-01

The influence of humic substances and protein compounds on the bioaccumulation of six types of perfluoroalkyl substances (PFASs) in Daphnia magna was compared. The humic substances included humic acid (HA) and fulvic acid (FA), the protein compounds included chicken egg albumin (albumin) and peptone, and the PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid. Four concentrations (0, 1, 10, and 20 mg L(-1)) of the four dissolved organic matter (DOM) types were investigated. At the 1 mg L(-1) level, HA and albumin enhanced all tested PFAS bioaccumulation, whereas FA and peptone only enhanced the bioaccumulation of shorter-chain PFASs (PFOS, PFOA, and PFNA). However, all four DOM types decreased all tested PFAS bioaccumulation at the 20 mg L(-1) level, and the decreasing ratios of bioaccumulation factors caused by FA, HA, albumin, and peptone were 1-49%, 23-77%, 17-58%, and 8-56%, respectively compared with those without DOM. This is because DOM not only reduced the bioavailable concentrations and uptake rates of PFASs but also lowered the elimination rates of PFASs in D. magna, and these opposite effects would change with different DOM types and concentrations. Although the partition coefficients (L kg(-1)) of PFASs between HA and water (10(4.21)-10(4.98)) were much lower than those between albumin and water (10(4.92)-10(5.86)), their effects on PFAS bioaccumulation were comparable. This study suggests that although PFASs are a type of proteinophilic compounds, humic substances also have important effects on their bioavailability and bioaccumulation in aquatic organisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, ZhiPing, E-mail: liulqs@163.com; Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020; Wu, WenHui

Highlights: • DOM fractions spectra analysis during the whole treatment process. • Efficient method was achieved to remove organic matters in landfill leachate. • Molecular weight distribution and fractions were discussed. - Abstract: A combined treatment process of air stripping + Fenton + sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD{sub 5}) and ammonia nitrogen (NH{sub 3}−N) by themore » combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW < 2 k and MW > 100 k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While small MW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.« less

Occurrence of pesticide non extractable residues in physical and chemical fractions from two natural soils.

NASA Astrophysics Data System (ADS)

Andreou, K.; Jones, K.; Semple, K.

2009-04-01

Distribution of pesticide non extractable residues resulted from the incubation of two natural soils with each of the isoproturon, diazinon and cypermethrin pesticide was assessed in this study. Pesticide non extractable residues distribution in soil physical and chemical fractions is known to ultimately affect their fate. This study aimed to address the fate and behaviour of the non extractable residues in the context of their association with soil physical and chemical fractions with varying properties and characteristics. Non extractable residues were formed from incubation of each pesticide in the two natural soils over a period of 24 months. Soils containing the non extractable residues were fractionated into three solid phase fractions using a physical fractionation procedure as follows: Sediment (SED, >20 μm), (II) Microaggregate (MA, 20-2 μm) and (III) Colloid phase (COL, 2-0.05 μm). Each soil fraction was then fractionated into organic carbon chemical fractionations as follows: Fulvic acid (FA), Humic acid (HA) and Humin (HM). Significant amount of the pesticides was lost during the incubation period. Enrichment factors for the organic carbon and the 14C-pesticide residues were higher in the MA and COL fraction rather than the SED fraction. Greater association and enrichment of the fulvic acid fraction of the organic carbon in the soil was observed. Non extractable residues at the FA fraction showed to diminish while in the HA fraction were increased with decreasing the fraction size. An appreciable amount of non extractable residues were located in the HM fraction but this was less than the amount recovered in the humic substances. Long term fate of pesticide non extractable residues in the soil structural components is important in order to assess any risk associated with them.

Differential osteogenic activity of osteoprogenitor cells on HA and TCP/HA scaffold of tissue engineered bone.

PubMed

Ng, Angela M H; Tan, K K; Phang, M Y; Aziyati, O; Tan, G H; Isa, M R; Aminuddin, B S; Naseem, M; Fauziah, O; Ruszymah, B H I

2008-05-01

Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering. Copyright 2007 Wiley Periodicals, Inc.

Sorption of Eu(III) on attapulgite studied by batch, XPS, and EXAFS techniques.

PubMed

Fan, Q H; Tan, X L; Li, J X; Wang, X K; Wu, W S; Montavon, G

2009-08-01

The effects of pH, ionic strength, and temperature on sorption of Eu(III) on attapulgite were investigated in the presence and absence of fulvic acid (FA) and humic acid (HA). The results indicated that the sorption of Eu(III) on attapulgite was strongly dependent on pH and ionic strength, and independent of temperature. In the presence of FA/HA, Eu(III) sorption was enhanced at pH < 4, decreased at pH range of 4-6, and then increased again at pH > 7. The X-ray photoelectron spectroscopy (XPS) analysis suggested that the sorption of Eu(III) might be expressed as is identical to X3Eu0, is identical to S(w)OHEu3+, and is identical to SOEu-OOC-/HA in the ternary Eu/HN/attapulgite system. The extended X-ray absorption fine structure (EXAFS) analysis of Eu-HA complexes indicated that the distances of d(Eu-O) decreased from 2.415 to 2.360 angstroms with increasing pH from 1.76 to 9.50, whereas the coordination number (N) decreased from approximately 9.94 to approximately 8.56. Different complexation species were also found for the different addition sequences of HA and Eu(III) to attapulgite suspension. The results are important to understand the influence of humic substances on Eu(III) behavior in the natural environment.

Acid-base and copper-binding properties of three organic matter fractions isolated from a forest floor soil solution

NASA Astrophysics Data System (ADS)

van Schaik, Joris W. J.; Kleja, Dan B.; Gustafsson, Jon Petter

2010-02-01

Vast amounts of knowledge about the proton- and metal-binding properties of dissolved organic matter (DOM) in natural waters have been obtained in studies on isolated humic and fulvic (hydrophobic) acids. Although macromolecular hydrophilic acids normally make up about one-third of DOM, their proton- and metal-binding properties are poorly known. Here, we investigated the acid-base and Cu-binding properties of the hydrophobic (fulvic) acid fraction and two hydrophilic fractions isolated from a soil solution. Proton titrations revealed a higher total charge for the hydrophilic acid fractions than for the hydrophobic acid fraction. The most hydrophilic fraction appeared to be dominated by weak acid sites, as evidenced by increased slope of the curve of surface charge versus pH at pH values above 6. The titration curves were poorly predicted by both Stockholm Humic Model (SHM) and NICA-Donnan model calculations using generic parameter values, but could be modelled accurately after optimisation of the proton-binding parameters (pH ⩽ 9). Cu-binding isotherms for the three fractions were determined at pH values of 4, 6 and 9. With the optimised proton-binding parameters, the SHM model predictions for Cu binding improved, whereas the NICA-Donnan predictions deteriorated. After optimisation of Cu-binding parameters, both models described the experimental data satisfactorily. Iron(III) and aluminium competed strongly with Cu for binding sites at both pH 4 and pH 6. The SHM model predicted this competition reasonably well, but the NICA-Donnan model underestimated the effects significantly at pH 6. Overall, the Cu-binding behaviour of the two hydrophilic acid fractions was very similar to that of the hydrophobic acid fraction, despite the differences observed in proton-binding characteristics. These results show that for modelling purposes, it is essential to include the hydrophilic acid fraction in the pool of 'active' humic substances.

Fate of 2,4,6-Trinitrotoluene in a Simulated Compost System

DTIC Science & Technology

1994-09-01

to the NaOH solution. The insoluble material remaining after the NaOH fractionation con- tained the humin fraction as well as remaining cellulose ...insoluble) (solb) HUMIN + CELLULOSE MIBK (insoluble) (MIBK) (aqueous) ICELLULOSE HUMIN HUMIC ACID + FULVIC ACID +HCI to pH 1 (insoLuble) (soluble...0.5 N NaOH (insoluble) (soluble) HUMIN+ CELLULOSE • MIBK (insoluble) (MIBK) (aqueous) CELLULOSE HUMIN HUMIC ACID + FULVIC ACID + HUMIN +HCl to pH 1

Comparison of structural features of water-soluble organic matter from atmospheric aerosols with those of aquatic humic substances

NASA Astrophysics Data System (ADS)

Duarte, Regina M. B. O.; Santos, Eduarda B. H.; Pio, Casimiro A.; Duarte, Armando C.

Elemental analysis, Fourier transform infrared coupled to attenuated total reflectance (FTIR-ATR) and solid-state cross polarization with magic angle spinning- 13C-nuclear magnetic resonance (CPMAS 13C NMR) spectroscopies were used to compare the chemical features of water-soluble organic compounds (WSOC) from atmospheric aerosols with those of aquatic humic and fulvic acids. The influence of different meteorological conditions on the structural composition of aerosol WSOC was also evaluated. Prior to the structural characterisation, the WSOC samples were separated into hydrophobic acids and hydrophilic acids fractions by using a XAD-8/XAD-4 isolation procedure. Results showed that WSOC hydrophobic acids are mostly aliphatic (40-62% of total NMR peak area), followed by oxygenated alkyls (15-21%) and carboxylic acid (5.4-13.4%) functional groups. Moreover, the aromatic content of aerosol WSOC samples collected between autumn and winter seasons is higher (˜18-19%) than that of samples collected during warmer periods (˜6-10%). The presence of aromatic signals typical of lignin-derived structures in samples collected during low-temperature conditions highlights the major contribution of wood burning processes in domestic fireplaces into the bulk chemical properties of WSOC from aerosols. According to our investigations, aerosol WSOC hydrophobic acids and aquatic fulvic and humic acids hold similar carbon functional groups; however, they differ in terms of the relative carbon distribution. Elemental analysis indicates that H and N contents of WSOC hydrophobic acids samples surpass those of aquatic fulvic and humic acids. In general, the obtained results suggest that WSOC hydrophobic acids have a higher aliphatic character and a lower degree of oxidation than those of standard fulvic and humic acids. The study here reported suggests that aquatic fulvic and humic acids may not be good models for WSOC from airborne particulate matter.

Interaction between Al3+ and acrylic acid and polyacrylic acid in acidic aqueous solution: a model experiment for the behavior of Al3+ in acidified soil solution.

PubMed

Etou, Mayumi; Masaki, Yuka; Tsuji, Yutaka; Saito, Tomoyuki; Bai, Shuqin; Nishida, Ikuko; Okaue, Yoshihiro; Yokoyama, Takushi

2011-01-01

From the viewpoint of the phytotoxicity and mobility of Al(3+) released from soil minerals due to soil acidification, the interaction between Al(3+) and acrylic acid (AA) and polyacrylic acid (PAA) as a model compound of fulvic acid was investigated. The interaction was examined at pH 3 so as to avoid the hydrolysis of Al(3+). The interaction between Al(3+) and AA was weak. However, the interaction between Al(3+) and PAA was strong and depended on the initial (COOH in PAA)/Al molar ratio (R(P)) of the solution. For the range of 1/R(P), the interaction between Al(3+) and PAA can be divided into three categories: (1) 1:1 Al-PAA-complex (an Al(3+) combines to a carboxyl group), (2) intermolecular Al-PAA-complex (an Al(3+) combines to more than 2 carboxyl groups of other Al-PAA-complexes) in addition to the 1:1 Al-PAA-complex and (3) precipitation of intermolecular complexes. In conclusion, R(P) is an important factor affecting the behavior of Al(3+) in acidic soil solution.

In vitro testing of calcium phosphate (HA, TCP, and biphasic HA-TCP) whiskers.

PubMed

Jalota, Sahil; Bhaduri, Sarit B; Tas, A Cuneyt

2006-09-01

Calcium phosphate [single-phase hydroxyapatite (HA, Ca(10)(PO(4))(6)(OH)(2)), single-phase tricalcium phosphate (beta-TCP, Ca(3)(PO(4))(2)), and biphasic HA-TCP] whiskers were formed by using a novel microwave-assisted molten salt mediated process. Aqueous solutions containing NaNO(3), HNO(3), Ca(NO(3))(2) x 4H(2)O, and KH(2)PO(4) (with or without urea) were used as starting reagents. These solutions were irradiated in a household microwave oven for 5 min. As-recovered precursors were then simply stirred in water at room temperature for 1 h to obtain the whiskers of the desired calcium phosphate (CaP) bioceramics. These whiskers were evaluated, respectively, in vitro by (1) soaking those in synthetic body fluid (SBF) solutions at 37 degrees C for one week, and (2) performing cell attachment and total protein assay tests on the neat whiskers by using a mouse osteoblast cell line (7F2). beta-TCP, HA, and HA-TCP biphasic whiskers were all found to possess apatite-inducing ability when soaked in SBF. SBF-soaked whiskers were found to have BET surface areas ranging from 45 to 112 m(2)/g. Although the osteoblast viability and protein concentrations were found to be the highest on the neat HA whiskers, cells were attached and proliferated on all the whiskers.

Photo-crosslinked hyaluronic acid coated upconverting nanoparticles

NASA Astrophysics Data System (ADS)

Mrazek, Jiri; Kettou, Sofiane; Matuska, Vit; Svozil, Vit; Huerta-Angeles, Gloria; Pospisilova, Martina; Nesporova, Kristina; Velebny, Vladimir

2017-02-01

Hyaluronic acid (HA)-coated inorganic nanoparticles display enhanced interaction with the CD44 receptors which are overexpressed in many types of cancer cells. Here, we describe a modification of core-shell β-NaY0.80Yb0.18Er0.02F4@NaYF4 nanoparticles (UCNP) by HA derivative bearing photo-reactive groups. UCNP capped with oleic acid were firstly transferred to aqueous phase by an improved protocol using hydrochloric acid or lactic acid treatment. Subsequently, HA bearing furanacryloyl moieties (HA-FU) was adsorbed on the nanoparticle surface and crosslinked by UV irradiation. The crosslinking resulted in stable HA coating, and no polymer desorption was observed. As-prepared UCNP@HA-FU show a hydrodynamic diameter of about 180 nm and are colloidally stable in water and cell culture media. The cellular uptake by normal human fibroblasts and MDA MB-231 cancer cell line was investigated by upconversion luminescence imaging.

Organic Pollutants in Soils, as Studied by Nuclear Magnetic Resonance

DTIC Science & Technology

1998-05-15

represented in most of this study by the ’ following major soil components: humics (humic acid, fulvic acid, humin), clays ( montmorillonite , kaolinite ...fulvic acids and clays ( kaolinite and montmorillonite ). This study was designed to provide the kind of fundamental chemical/physical information...elemental analysis and 29Si and 27A1 NMR data, are a kaolinite and a Ca- montmorillonite obtained from the Missouri Clay Repository, Columbia, MO. Figures

Environment Sentinel Biomonitor Technology Assessment

DTIC Science & Technology

2013-09-01

turbidity, humic /fulvic acids , geosmin/MIB, hard water) with minimal effect on test outcome. It is better to be able to operate under a wide range...inhibition between 20–80%. c. Susceptibility to source water conditions: very low i. No response for pH (4.5–9), geosmin, MIB, humic /fulvic acids , or hard

Hyaluronic Acid (HA)-Polyethylene glycol (PEG) as injectable hydrogel for intervertebral disc degeneration patients therapy

NASA Astrophysics Data System (ADS)

Putri Kwarta, Cityta; Widiyanti, Prihartini; Siswanto

2017-05-01

Chronic Low Back Pain (CLBP) is one health problem that is often encountered in a community. Inject-able hydrogels are the newest way to restore the disc thickness and hydration caused by disc degeneration by means of minimally invasive surgery. Thus, polymers can be combined to improve the characteristic properties of inject-able hydrogels, leading to use of Hyaluronic Acid (a natural polymer) and Polyethylene glycol (PEG) with Horse Radish Peroxide (HRP) cross linker enzymes. The swelling test results, which approaches were the ideal disc values, were sampled with variation of enzyme concentrations of 0.25 µmol/min/mL. The enzyme concentrations were 33.95%. The degradation test proved that the sample degradation increased along with the decrease of the HRP enzyme concentration. The results of the cytotoxicity assay with MTT assay method showed that all samples resulted in the 90% of living cells are not toxic. In vitro injection, models demonstrated that higher concentration of the enzymes was less state of gel which would rupture when released from the agarose gel. The functional group characterization shows the cross linking bonding in sample with enzyme adding. The conclusion of this study is PEG-HA-HRP enzyme are safe polymer composites which have a potential to be applied as an injectable hydrogel for intervertebral disc degeneration.

Effect of bioactive extruded PLA/HA composite films on focal adhesion formation of preosteoblastic cells.

PubMed

Persson, Maria; Lorite, Gabriela S; Kokkonen, Hanna E; Cho, Sung-Woo; Lehenkari, Petri P; Skrifvars, Mikael; Tuukkanen, Juha

2014-09-01

The quality of the initial cell attachment to a biomaterial will influence any further cell function, including spreading, proliferation, differentiation and viability. Cell attachment is influenced by the material's ability to adsorb proteins, which is related to the surface chemistry and topography of the material. In this study, we incorporated hydroxyapatite (HA) particles into a poly(lactic acid) (PLA) composite and evaluated the surface structure and the effects of HA density on the initial cell attachment in vitro of murine calvarial preosteoblasts (MC3T3-EI). Scanning electron microscopy (SEM), atomic force microscopy (AFM) and infrared spectroscopy (FTIR) showed that the HA particles were successfully incorporated into the PLA matrix and located at the surface which is of importance in order to maintain the bioactive effect of the HA particles. SEM and AFM investigation revealed that the HA density (particles/area) as well as surface roughness increased with HA loading concentration (i.e. 5, 10, 15 and 20wt%), which promoted protein adsorption. Furthermore, the presence of HA on the surface enhanced cell spreading, increased the formation of actin stress fibers and significantly improved the expression of vinculin in MC3T3-E1 cells which is a key player in the regulation of cell adhesion. These results suggest the potential utility of PLA/HA composites as biomaterials for use as a bone substitute material and in tissue engineering applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Interaction of humic acids and humic-acid-like polymers with herpes simplex virus type 1

NASA Astrophysics Data System (ADS)

Klöcking, Renate; Helbig, Björn

The study was performed in order to compare the antiviral activity against herpes simplex virus type 1 (HSV-1) of synthetic humic-acid-like polymers to that of their low-molecular-weight basic compounds and naturally occurring humic acids (HA) in vitro. HA from peat water showed a moderate antiviral activity at a minimum effective concentration (MEC) of 20 µg/ml. HA-like polymers, i.e. the oxidation products of caffeic acid (KOP), hydrocaffeic acid (HYKOP), chlorogenic acid (CHOP), 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), nordihydroguaretic acid (NOROP), gentisinic acid (GENOP), pyrogallol (PYROP) and gallic acid (GALOP), generally inhibit virus multiplication, although with different potency and selectivity. Of the substances tested, GENOP, KOP, 3,4-DHPOP and HYKOP with MEC values in the range of 2 to 10 µg/ml, proved to be the most potent HSV-1 inhibitors. Despite its lower antiviral potency (MEC 40 µg/ml), CHOP has a remarkable selectivity due to the high concentration of this polymer that is tolerated by the host cells (>640 µg/ml). As a rule, the antiviral activity of the synthetic compounds was restricted to the polymers and was not preformed in the low-molecular-weight basic compounds. This finding speaks in favour of the formation of antivirally active structures during the oxidative polymerization of phenolic compounds and, indirectly, of corresponding structural parts in different HA-type substances.

Increased Level of α2,6-Sialylated Glycans on HaCaT Cells Induced by Titanium Dioxide Nanoparticles under UV Radiation

PubMed Central

Liu, Xin; Geng, Runqing; Rao, Rong; Tan, Xi; Yang, Xiangliang; Liu, Wei

2018-01-01

As one of the most widely used nanomaterials, the safety of nano-TiO2 for human beings has raised concern in recent years. Sialylation is an important glycosylation modification that plays a critical role in signal transduction, apoptosis, and tumor metastasis. The aim of this work was to investigate the cytotoxicity and phototoxicity of nano-TiO2 with different crystalline phases for human skin keratinocytes (HaCaT cells) under ultraviolet (UV) irradiation and detect sialic acid alterations. The results showed that the mixture of crystalline P25 had the highest cytotoxicity and phototoxicity, followed by pure anatase A25, whereas pure rutile R25 had the lowest cytotoxicity and phototoxicity. A25 and R25 had no effects on the expression of sialic acids on HaCaT cells. However, HaCaT cells treated with P25 and UV showed an increased level of alterations in α2,6-linked sialic acids, which was related to the level of reactive oxygen species (ROS) generated by nano-TiO2 and UV. The abundance of α2,6-linked sialic acids increased as ROS production increased, and vice versa. Antioxidant vitamin C (VC) reversed the abnormal expression of α2,6-linked sialic acids caused by nano-TiO2 and protected cells by eliminating ROS. These findings indicate that nano-TiO2 can alter the sialylation status of HaCaT cells under UV irradiation in a process mediated by ROS. PMID:29671762

The Effects of Topically Applied Glycolic Acid and Salicylic Acid on Ultraviolet Radiation-Induced Erythema, DNA Damage and Sunburn Cell Formation in Human Skin

PubMed Central

Kornhauser, Andrija; Wei, Rong-Rong; Yamaguchi, Yuji; Coelho, Sergio G.; Kaidbey, Kays; Barton, Curtis; Takahashi, Kaoruko; Beer, Janusz Z.; Miller, Sharon A.; Hearing, Vincent J.

2009-01-01

Background α-Hydroxy acids (αHA) are reported to reduce signs of aging in the skin and are widely used cosmetic ingredients. Several studies suggest that αHA can increase the sensitivity of skin to ultraviolet radiation. More recently, β-hydroxy acids (βHA), or combinations of αHA and βHA have also been incorporated into antiaging skin care products. Concerns have also arisen about increased sensitivity to ultraviolet radiation following use of skin care products containing β-HA. Objective To determine whether topical treatment with glycolic acid, a representative αHA, or with salicylic acid, a βHA, modifies the short-term effects of solar simulated radiation (SSR) in human skin. Methods Fourteen subjects participated in this study. Three of the four test sites on the mid-back of each subject were treated daily Monday - Friday, for a total of 3.5 weeks, with glycolic acid (10%), salicylic acid (2%), or vehicle (control). The fourth site received no treatment. After the last treatment, each site was exposed to SSR, and shave biopsies from all 4 sites were obtained. The endpoints evaluated in this study were erythema (assessed visually and instrumentally), DNA damage and sunburn cell formation. Results Treatment with glycolic acid resulted in increased sensitivity of human skin to SSR, measured as an increase in erythema, DNA damage and sunburn cell formation. Salicylic acid did not produce significant changes in any of these biomarkers. Conclusions Short-term topical application of glycolic acid in a cosmetic formulation increased the sensitivity of human skin to SSR, while a comparable treatment with salicylic acid did not. PMID:19411163

Intravesical administration of combined hyaluronic acid (HA) and chondroitin sulfate (CS) for the treatment of female recurrent urinary tract infections: a European multicentre nested case-control study.

PubMed

Ciani, Oriana; Arendsen, Erik; Romancik, Martin; Lunik, Richard; Costantini, Elisabetta; Di Biase, Manuel; Morgia, Giuseppe; Fragalà, Eugenia; Roman, Tomaskin; Bernat, Marian; Guazzoni, Giorgio; Tarricone, Rosanna; Lazzeri, Massimo

2016-03-31

To compare the clinical effectiveness of the intravesical administration of combined hyaluronic acid and chondroitin sulfate (HA+CS) versus current standard management in adult women with recurrent urinary tract infections (RUTIs). A European Union-based multicentre, retrospective nested case-control study. 276 adult women treated for RUTIs starting from 2009 to 2013. Patients treated with either intravesical administration of HA+CS or standard of care (antimicrobial/immunoactive prophylaxis/probiotics/cranberry). The primary outcome was occurrence of bacteriologically confirmed recurrence within 12 months. Secondary outcomes were time to recurrence, total number of recurrences, health-related quality of life and healthcare resource consumption. Crude and adjusted results for unbalanced characteristics are presented. 181 patients treated with HA+CS and 95 patients treated with standard of care from 7 centres were included. The crude and adjusted ORs (95% CI) for the primary end point were 0.77 (0.46 to 1.28) and 0.51 (0.27 to 0.96), respectively. However, no evidence of improvement in terms of total number of recurrences (incidence rate ratio (95% CI), 0.99 (0.69 to 1.43)) or time to first recurrence was seen (HR (95% CI), 0.99 (0.61 to 1.61)). The benefit of intravesical HA+CS therapy improves when the number of instillations is ≥ 5. Our results show that bladder instillations of combined HA+CS reduce the risk of bacteriologically confirmed recurrences compared with the current standard management of RUTIs. Total incidence rates and hazard rates were instead non-significantly different between the 2 groups after adjusting for unbalanced factors. In contrast to what happens with antibiotic prophylaxis, the effectiveness of the HA+CS reinstatement therapy improves over time. NCT02016118. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Effect of humic acid source on humic acid adsorption onto titanium dioxide nanoparticles.

PubMed

Erhayem, Mohamed; Sohn, Mary

2014-02-01

In many studies, different humic acid (HA) sources are used interchangeably to evaluate the effect of organic matter on geochemical processes in the environment. This research looks more specifically at the effect of HA source on HA adsorption onto nano-TiO2 and how HA adsorption affects the fate and transport of nano-TiO2. In this study, six humic acids (HAs) were studied which were derived from soils (SLHA), or from sediments (SDHA) all originating from the state of Florida. Humic acid adsorption onto titanium dioxide nanoparticles (nano-TiO2) and the sedimentation of HA-coated and uncoated nano-TiO2 were monitored by Ultraviolet-visible (UV-vis) spectroscopy. Synchronous scan fluorescence (SSF) spectroscopy was used to complement the study of HA adsorption onto nano-TiO2. Phosphate buffer was found to reduce the amount of HA adsorbed onto nano-TiO2 relative to solutions of NaCl of the same pH and ionic strength. Adsorption constant values (Kads) for HAs varied in the order SLHA>FSDHA (freshwater sedimentary HA)>ESDHA (estuarine sedimentary HA). SSF results suggested that the more highly conjugated fractions of HA, which are more prevalent in SLHAs versus SDHAs, were preferentially adsorbed. In order to better understand the relationship between adsorption and aggregation, sedimentation studies were conducted and it was found that the percentage of nano-TiO2 sedimentation was preferentially enhanced in the order of the presence of SLHA>FSDHA>ESDHA. The extent of nano-TiO2 sedimentation was decreased with increasing HA concentration. TEM imaging of nano-TiO2 confirmed that nano-TiO2 was aggregated in the presence of HAs. The findings in this study suggest that HAs from different sources influence the fate and transport of nano-TiO2 in the environment differently. © 2013.

Stimulation of TLRs by LMW-HA induces self-defense mechanisms in vaginal epithelium.

PubMed

Dusio, Giuseppina F; Cardani, Diego; Zanobbio, Laura; Mantovani, Martina; Luchini, Patrizia; Battini, Lorenzo; Galli, Valentina; Diana, Angela; Balsari, Andrea; Rumio, Cristiano

2011-07-01

The innate immune system is present throughout the female reproductive tract and functions in synchrony with the adaptive immune system to provide protection in a way that enhances the chances for fetal survival, while protecting against potential pathogens. Recent data show that activation of Toll-like receptor (TLR)2 and 4 by low-molecular weight hyaluronic acid (LMW-HA) in the epidermis induces secretion of the antimicrobial peptide β-defensin 2. In the present work, we show that LMW-HA induces vaginal epithelial cells to release different antimicrobial peptides, via activation of TLR2 and TLR4. Further, we found that LMW-HA favors repair of vaginal epithelial injury, involving TLR2 and TLR4, and independently from its classical receptor CD44. This wound-healing activity of LMW-HA is dependent from an Akt/phosphatidylinositol 3 kinase pathway. Therefore, these findings suggest that the vaginal epithelium is more than a simple physical barrier to protect against invading pathogens: on the contrary, this surface acts as efficient player of innate host defense, which may modulate its antimicrobial properties and injury restitution activity, following LMW-HA stimulation; this activity may furnish an additional protective activity to this body compartment, highly and constantly exposed to microbiota, ameliorating the self-defense of the vaginal epithelium in both basal and pathological conditions.

Molecular aspects of zygotic embryogenesis in sunflower (Helianthus annuus L.): correlation of positive histone marks with HaWUS expression and putative link HaWUS/HaL1L.

PubMed

Salvini, Mariangela; Fambrini, Marco; Giorgetti, Lucia; Pugliesi, Claudio

2016-01-01

The link HaWUS/ HaL1L , the opposite transcriptional behavior, and the decrease/increase in positive histone marks bond to both genes suggest an inhibitory effect of WUS on HaL1L in sunflower zygotic embryos. In Arabidopsis, a group of transcription factors implicated in the earliest events of embryogenesis is the WUSCHEL-RELATED HOMEOBOX (WOX) protein family including WUSCHEL (WUS) and other 14 WOX protein, some of which contain a conserved WUS-box domain in addition to the homeodomain. WUS transcripts appear very early in embryogenesis, at the 16-cell embryo stage, but gradually become restricted to the center of the developing shoot apical meristem (SAM) primordium and continues to be expressed in cells of the niche/organizing center of SAM and floral meristems to maintain stem cell population. Moreover, WUS has decisive roles in the embryonic program presumably promoting the vegetative-to-embryonic transition and/or maintaining the identity of the embryonic stem cells. However, data on the direct interaction between WUS and key genes for seed development (as LEC1 and L1L) are not collected. The novelty of this report consists in the characterization of Helianthus annuus WUS (HaWUS) gene and in its analysis regarding the pattern of the methylated lysine 4 (K4) of the Histone H3 and of the acetylated histone H3 during the zygotic embryo development. Also, a parallel investigation was performed for HaL1L gene since two copies of the WUS-binding site (WUSATA), previously identified on HaL1L nucleotide sequence, were able to be bound by the HaWUS recombinant protein suggesting a not described effect of HaWUS on HaL1L transcription.

Comparative evaluation of humic substances in oral drug delivery.

PubMed

Mirza, Mohd Aamir; Ahmad, Niyaz; Agarwal, Suraj Prakash; Mahmood, Danish; Khalid Anwer, M; Iqbal, Z

2011-05-01

Major and biologically most explored components of natural organic matter (NOM) are humic acid (HA) and fulvic acid (FA). We have explored rock shilajit as a source of NOM. On the other hand carbamazepine (CBZ) is a well known anticonvulsant drug and has a limited accessibility to brain. Bioavailability and pharmacokinetic profiles of CBZ have been improved by complexation and different techniques also. Present study has assessed the comparative abilities of FA and HA as complexing agent for CBZ in order to enhance pharmacokinetic profile of CBZ and accessibility to the brain. These two complexing agents have been compared on various indices such as their abilities to cause complexation and enhance solubility, permeability and dissolution. The present study also compared pharmacodynamic and biochemical profiles after oral administration of complexes. With the help of various pharmaceutical techniques such as freeze drying, physical mixture, kneading and solvent evaporation, two molar ratios (1:1 and 1:2) were selected for complexation and evaluated for conformational analysis (molecular modeling). Complex formed was further characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), mass spectroscopy and X-ray diffraction (XRD). Preclinical study on rodents with CBZ-HA and CBZ-FA has yielded appreciable results in terms of their anticonvulsant and antioxidants activities. However, CBZ-HA (1:2) demonstrated better result than any other complex.

Comparative evaluation of humic substances in oral drug delivery

PubMed Central

Mirza, Mohd. Aamir; Ahmad, Niyaz; Agarwal, Suraj Prakash; Mahmood, Danish; Khalid Anwer, M.; Iqbal, Z.

2011-01-01

Major and biologically most explored components of natural organic matter (NOM) are humic acid (HA) and fulvic acid (FA). We have explored rock shilajit as a source of NOM. On the other hand carbamazepine (CBZ) is a well known anticonvulsant drug and has a limited accessibility to brain. Bioavailability and pharmacokinetic profiles of CBZ have been improved by complexation and different techniques also. Present study has assessed the comparative abilities of FA and HA as complexing agent for CBZ in order to enhance pharmacokinetic profile of CBZ and accessibility to the brain. These two complexing agents have been compared on various indices such as their abilities to cause complexation and enhance solubility, permeability and dissolution. The present study also compared pharmacodynamic and biochemical profiles after oral administration of complexes. With the help of various pharmaceutical techniques such as freeze drying, physical mixture, kneading and solvent evaporation, two molar ratios (1:1 and 1:2) were selected for complexation and evaluated for conformational analysis (molecular modeling). Complex formed was further characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), mass spectroscopy and X-ray diffraction (XRD). Preclinical study on rodents with CBZ–HA and CBZ–FA has yielded appreciable results in terms of their anticonvulsant and antioxidants activities. However, CBZ–HA (1:2) demonstrated better result than any other complex. PMID:25755978

Visible light photodegradation of phenanthrene catalyzed by Fe(III)-smectite: role of soil organic matter.

PubMed

Jia, Hanzhong; Li, Li; Fan, Xiaoyun; Liu, Mingdeng; Deng, Wenye; Wang, Chuanyi

2013-07-15

In the present study, phenanthrene is employed as a model to explore the roles played by three soil organic matter (SOM) fractions, i.e., dissolved organic matter (DOM), humic acid (HA), and fulvic acid (FA), in its photodegradation with assistance of Fe(III)-smectite under visible-light. Slight decrease in phenanthrene photodegradation rate was observed in the presence of DOM, which is explained in terms of oxidative-radical competition between DOM and target phenanthrene molecules due to the high electron-donor capacity of phenolic moieties in DOM. On the other hand, a critic content is observed with FA (0.70mg/g) and HA (0.65mg/g). Before reaching the critic content, the removal of phenanthrene is accelerated; while after that, the photodegradation rate is suppressed. The acceleration of phenanthrene degradation can be attributed to the photosensitization of FA and HA. Due to the strong interaction between phenanthrene and the phenyl rings, however, the retention of phenanthrene on SOM-Fe(III)-smectite in the presence of high content of HA or FA is enhanced, thus slowing down its photodegradation. Those observations provide valuable insights into the transformation and fate of PAHs in the natural soil environment and open a window for using clay-humic substances complexes for remediation of contaminated soil. Copyright © 2013 Elsevier B.V. All rights reserved.

Aquatic humic substances inhibit clastogenic events in germinating seeds of herbaceous plants.

PubMed

Ferrara, G; Loffredo, E; Senesi, N

2001-03-01

One humic acid (HA) and two fulvic acids (FAs) of aquatic origin have been tested for their capacity to inhibit clastogenic events caused by maleic hydrazide (MH) in germinating seeds of the herbaceous plant species Allium cepa and Vicia faba. Either HA or FA at concentrations of 50 and 500 mg L(-)(1) was interacted with 10 mg L(-)(1) MH for 24 h before addition to the seeds. The evaluation of genotoxic activity was made by counting micronuclei (MN) and aberrant anatelophases (AT) in root tip cells after treatment with HA or FA alone, MH alone, and interacted HA + MH and FA + MH. Regular AT were also counted as an index of mitotic activity. In all cases HA and FA interacted with MH showed an evident anticlastogenic action indicated by the marked reduction of genetic anomalies. In A. cepa, the anticlastogenic effect of HA and FA was more significant for aberrant AT than for MN, whereas the opposite was true in the case of V. faba. The protective effect exhibited for both anomalies by HA was slightly higher than that of the corresponding FA in A. cepa, whereas no significant differences between these HA and FA treatments were observed in the case of V. faba. The two FAs generally showed similar anticlastogenic behaviors with slight quantitative differences observed as a function of the type of anomaly and the plant species. The effects of HA and FA concentration differed depending on the type of anomaly observed, the plant species, and FA origin. In V. faba, cell division, that is, the number of regular AT, was generally depressed by HA and FA at either concentration with respect to the control. In A. cepa, HA and FA produced either stimulating or inhibiting effects on regular AT depending on their nature, origin, and concentration.

Synthesis and Hydrolytic Degradation of Substituted Poly(DL-Lactic Acid)s

PubMed Central

Tsuji, Hideto; Eto, Takehiko; Sakamoto, Yuzuru

2011-01-01

Non-substituted racemic poly(DL-lactic acid) (PLA) and substituted racemic poly(DL-lactic acid)s or poly(DL-2-hydroxyalkanoic acid)s with different side-chain lengths, i.e., poly(DL-2-hydroxybutanoic acid) (PBA), poly(DL-2-hydroxyhexanoic acid) (PHA), and poly(DL-2-hydroxydecanoic acid) (PDA) were synthesized by acid-catalyzed polycondensation of DL-lactic acid (LA), DL-2-hydroxybutanoic acid (BA), DL-2-hydroxyhexanoic acid (HA), and DL-2-hydroxydecanoic acid (DA), respectively. The hydrolytic degradation behavior was investigated in phosphate-buffered solution at 80 and 37 °C by gravimetry and gel permeation chromatography. It was found that the reactivity of monomers during polycondensation as monitored by the degree of polymerization (DP) decreased in the following order: LA > DA > BA > HA. The hydrolytic degradation rate traced by DP and weight loss at 80 °C decreased in the following order: PLA > PDA > PHA > PBA and that monitored by DP at 37 °C decreased in the following order: PLA > PDA > PBA > PHA. LA and PLA had the highest reactivity during polymerization and hydrolytic degradation rate, respectively, and were followed by DA and PDA. BA, HA, PBA, and PHA had the lowest reactivity during polymerization and hydrolytic degradation rate. The findings of the present study strongly suggest that inter-chain interactions play a major role in the reactivity of non-substituted and substituted LA monomers and degradation rate of the non-substituted and substituted PLA, along with steric hindrance of the side chains as can be expected. PMID:28824149

Environmental characteristics and changes of sediment pore water dissolved organic matter in four Chinese lakes.

PubMed

Mostofa, Khan M G; Li, Wen; Wu, Fengchang; Liu, Cong-Qiang; Liao, Haiqing; Zeng, Li; Xiao, Min

2018-01-01

Sediment pore waters were examined in four Chinese lakes (Bosten, Qinghai, Chenghai and Dianchi) to characterise the sources of dissolved organic matter (DOM) and their microbial changes in the sediment depth profiles. Parallel factor (PARAFAC) modelling on the sample fluorescence spectra confirmed that the pore water DOM was mostly composed of two components with a mixture of both allochthonous and autochthonous fulvic acid-like substances in three lakes, except Lake Dianchi, and protein-like components in Lake Bosten. However, DOM in Lake Dianchi was composed of three components, including a fulvic acid-like, and two unidentified components, which could originate from mixed sources of either sewerage-impacted allochthonous or autochthonous organic matter (OM). Dissolved organic carbon (DOC) concentrations were typically high (583-7410 μM C) and fluctuated and increased vertically in the depth profile. The fluorescence intensity of the fulvic acid-like substance and absorbance at 254 nm increased vertically in the sediment pore waters of three lakes. A significant relationship between DOC and the fluorescence intensity of the fulvic acid-like component in the sediment pore waters of three lakes, except Lake Dianchi, suggested that the fulvic acid-like component could significantly contribute to total DOM and could originate via complex microbial processes in early diagenesis on OM (ca. phytoplankton, terrestrial plant material) in these lakes. Pore water DOM components could therefore be a useful indicator to assess the DOM sources of the lake sediment during sedimentation over the past several decades, which have been heavily affected by ambient terrestrial vegetation and human activities.

Vaccine-induced anti-HA2 antibodies promote virus fusion and enhance influenza virus respiratory disease.

PubMed

Khurana, Surender; Loving, Crystal L; Manischewitz, Jody; King, Lisa R; Gauger, Phillip C; Henningson, Jamie; Vincent, Amy L; Golding, Hana

2013-08-28

Vaccine-induced disease enhancement has been described in connection with several viral vaccines in animal models and in humans. We investigated a swine model to evaluate mismatched influenza vaccine-associated enhanced respiratory disease (VAERD) after pH1N1 infection. Vaccinating pigs with whole inactivated H1N2 (human-like) virus vaccine (WIV-H1N2) resulted in enhanced pneumonia and disease after pH1N1 infection. WIV-H1N2 immune sera contained high titers of cross-reactive anti-pH1N1 hemagglutinin (HA) antibodies that bound exclusively to the HA2 domain but not to the HA1 globular head. No hemagglutination inhibition titers against pH1N1 (challenge virus) were measured. Epitope mapping using phage display library identified the immunodominant epitope recognized by WIV-H1N2 immune sera as amino acids 32 to 77 of pH1N1-HA2 domain, close to the fusion peptide. These cross-reactive anti-HA2 antibodies enhanced pH1N1 infection of Madin-Darby canine kidney cells by promoting virus membrane fusion activity. The enhanced fusion activity correlated with lung pathology in pigs. This study suggests a role for fusion-enhancing anti-HA2 antibodies in VAERD, in the absence of receptor-blocking virus-neutralizing antibodies. These findings should be considered during the evaluation of universal influenza vaccines designed to elicit HA2 stem-targeting antibodies.

In vitro study of RRS HA injectable mesotherapy/biorevitalization product on human skin fibroblasts and its clinical utilization

PubMed Central

Deglesne, Pierre-Antoine; Arroyo, Rodrigo; Ranneva, Evgeniya; Deprez, Philippe

2016-01-01

Mesotherapy/biorevitalization with hyaluronic acid (HA) is a treatment approach currently used for skin rejuvenation. Various products with a wide range of polycomponent formulations are available on the market. Most of these formulations contain noncross-linked HA in combination with a biorevitalization cocktail, formed by various amounts of vitamins, minerals, amino acids, nucleotides, coenzymes, and antioxidants. Although ingredients are very similar among the different products, in vitro and clinical effects may vary substantially. There is a real need for better characterization of these products in terms of their action on human skin or in vitro skin models. In this study, we analyzed the effect of the RRS® (Repairs, Refills, Stimulates) HA injectable medical device on human skin fibroblasts in vitro. Skin fibroblast viability and its capacity to induce the production of key extracellular matrix were evaluated in the presence of different concentrations of RRS HA injectable. Viability was evaluated through colorimetric MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay, and key extracellular matrix genes, type I collagen and elastin, were quantified by quantitative polymerase chain reaction. Results demonstrated that RRS HA injectable could promote human skin fibroblast viability (+15%) and increase fibroblast gene expression of type I collagen and elastin by 9.7-fold and 14-fold in vitro, respectively. These results demonstrate that mesotherapy/biorevitalization products can, at least in vitro, effectively modulate human skin fibroblasts. PMID:26966384

Toward understanding the role of individual fluorescent components in DOM-metal binding.

PubMed

Wu, Jun; Zhang, Hua; Yao, Qi-Sheng; Shao, Li-Ming; He, Pin-Jing

2012-05-15

Knowledge on the function of individual fractions in dissolved organic matter (DOM) is essential for understanding the impact of DOM on metal speciation and migration. Herein, fluorescence excitation-emission matrix quenching and parallel factor (PARAFAC) analysis were adopted for bulk DOM and chemically isolated fractions from landfill leachate, i.e., humic acids (HA), fulvic acids and hydrophilic (HyI) fraction, to elucidate the role of individual fluorescent components in metal binding (Cu(II) and Cd(II)). Three components were identified by PARAFAC model, including one humic substance (HS)-like, one protein-like and one component highly correlated with the HyI fraction. Among them, the HS-like and protein-like components were responsible for Cu(II) binding, while the protein-like component was the only fraction involved in Cd(II) complexation. It was further identified that the slight quenching effect of HA fraction by Cd(II) was induced by the presence of proteinaceous materials in HA. Fluorescent substances in the HyI fraction of landfill leachate did not play as important a role as HS did. Therefore, it was suggested that the potential risk of aged leachate (more humified) as a carrier of heavy metal should not be overlooked. Copyright © 2012 Elsevier B.V. All rights reserved.

Trypanosoma cruzi H+-ATPase 1 (TcHA1) and 2 (TcHA2) genes complement yeast mutants defective in H+ pumps and encode plasma membrane P-type H+-ATPases with different enzymatic properties.

PubMed

Luo, Shuhong; Scott, David A; Docampo, Roberto

2002-11-15

Previous studies in Trypanosoma cruzi have shown that intracellular pH homeostasis requires ATP and is affected by H(+)-ATPase inhibitors, indicating a major role for ATP-driven proton pumps in intracellular pH control. In the present study, we report the cloning and sequencing of a pair of genes linked in tandem (TcHA1 and TcHA2) in T. cruzi which encode proteins with homology to fungal and plant P-type proton-pumping ATPases. The genes are expressed at the mRNA level in different developmental stages of T. cruzi: TcHA1 is expressed maximally in epimastigotes, whereas TcHA2 is expressed predominantly in trypomastigotes. The proteins predicted from the nucleotide sequence of the genes have 875 and 917 amino acids and molecular masses of 96.3 and 101.2 kDa, respectively. Full-length TcHA1 and an N-terminal truncated version of TcHA2 complemented a Saccharomyces cerevisiae strain deficient in P-type H(+)-ATPase activity, the proteins localized to the yeast plasma membrane, and ATP-driven proton pumping could be detected in proteoliposomes reconstituted from plasma membrane purified from transfected yeast. The reconstituted proton transport activity was reduced by inhibitors of P-type H(+)-ATPases. C-terminal truncation did not affect complementation of mutant yeast, suggesting the lack of C-terminal autoinhibitory domains in these proteins. ATPase activity in plasma membrane from TcHA1- and (N-terminal truncated) TcHA2-transfected yeast was inhibited to different extents by vanadate, whereas the latter yeast strain was more resistant to extremes of pH, suggesting that the native proteins may serve different functions at different stages in the T. cruzi life cycle.

Secondary Structures in a Freeze-Dried Lignite Humic Acid Fraction Caused by Hydrogen-Bonding of Acidic Protons with Aromatic Rings.

PubMed

Cao, Xiaoyan; Drosos, Marios; Leenheer, Jerry A; Mao, Jingdong

2016-02-16

A lignite humic acid (HA) was separated from inorganic and non-HA impurities (i.e., aluminosilicates, metals) and fractionated by a combination of dialysis and XAD-8 resin. Fractionation revealed a more homogeneous structure of lignite HA. New and more specific structural information on the main lignite HA fraction is obtained by solid-state nuclear magnetic resonance (NMR) spectroscopy. Quantitative (13)C multiple cross-polarization (multiCP) NMR indicated oxidized phenyl propane structures derived from lignin. MultiCP experiments, conducted on potassium HA salts titrated to pH 10 and pH 12, revealed shifts consistent with carboxylate and phenolate formation, but structural changes associated with enolate formation from aromatic beta keto acids were not detected. Two-dimensional (1)H-(13)C heteronuclear correlation (2D HETCOR) NMR indicated aryl-aliphatic ketones, aliphatic and aromatic carboxyl groups, phenol, and methoxy phenyl ethers. Acidic protons from carboxyl groups in both the lignite HA fraction and a synthetic HA-like polycondensate were found to be hydrogen-bonded with electron-rich aromatic rings. Our results coupled with published infrared spectra provide evidence for the preferential hydrogen bonding of acidic hydrogens with electron-rich aromatic rings rather than adjacent carbonyl groups. These hydrogen-bonding interactions likely result from stereochemical arrangements in primary structures and folding.

Characterization of New PEEK/HA Composites with 3D HA Network Fabricated by Extrusion Freeforming.

PubMed

Vaezi, Mohammad; Black, Cameron; Gibbs, David M R; Oreffo, Richard O C; Brady, Mark; Moshrefi-Torbati, Mohamed; Yang, Shoufeng

2016-05-26

Addition of bioactive materials such as calcium phosphates or Bioglass, and incorporation of porosity into polyetheretherketone (PEEK) has been identified as an effective approach to improve bone-implant interfaces and osseointegration of PEEK-based devices. In this paper, a novel production technique based on the extrusion freeforming method is proposed that yields a bioactive PEEK/hydroxyapatite (PEEK/HA) composite with a unique configuration in which the bioactive phase (i.e., HA) distribution is computer-controlled within a PEEK matrix. The 100% interconnectivity of the HA network in the biocomposite confers an advantage over alternative forms of other microstructural configurations. Moreover, the technique can be employed to produce porous PEEK structures with controlled pore size and distribution, facilitating greater cellular infiltration and biological integration of PEEK composites within patient tissue. The results of unconfined, uniaxial compressive tests on these new PEEK/HA biocomposites with 40% HA under both static and cyclic mode were promising, showing the composites possess yield and compressive strength within the range of human cortical bone suitable for load bearing applications. In addition, preliminary evidence supporting initial biological safety of the new technique developed is demonstrated in this paper. Sufficient cell attachment, sustained viability in contact with the sample over a seven-day period, evidence of cell bridging and matrix deposition all confirmed excellent biocompatibility.

Effect of Natural Organic Matter on Plutonium Sorption to Goethite

DOE PAGES

Conroy, Nathan A.; Zavarin, Mavrik; Kersting, Annie B.; ...

2016-11-21

For this research, the effect of citric acid (CA), desferrioxamine B (DFOB), fulvic acid (FA), and humic acid (HA) on plutonium (Pu) sorption to goethite was studied as a function of organic carbon concentration and pH using batch sorption experiments at 5 mg C·L –1 and 50 mg C·L –1 natural organic matter (NOM), 10 –9–10 –10 M 238Pu, and 0.1 g·L –1 goethite concentrations, at pH 3, 5, 7, and 9. Low sorption of ligands coupled with strong Pu complexation decreased Pu sorption at pH 5 and 7, relative to a ligand-free system. Conversely, CA, FA, and HA increasedmore » Pu sorption to goethite at pH 3, suggesting ternary complex formation or, in the case of humic acid, incorporation into HA aggregates. Mechanisms for ternary complex formation were characterized by Fourier transform infrared spectroscopy in the absence of Pu. CA and FA demonstrated clear surface interactions at pH 3, HA appeared unchanged suggesting HA aggregates had formed, and no DFOB interactions were observed. Plutonium sorption decreased in the presence of DFOB (relative to a ligand free system) at all pH values examined. Thus, DFOB does not appear to facilitate formation of ternary Pu-DFOB-goethite complexes. At pH 9, Pu sorption in the presence of all NOM increased relative to pH 5 and 7; speciation models attributed this to Pu(IV) hydrolysis competing with ligand complexation, increasing sorption. In conclusion, the results indicate that in simple Pu-NOM-goethite ternary batch systems, NOM will decrease Pu sorption to goethite at all but particularly low pH conditions.« less

Effect of Natural Organic Matter on Plutonium Sorption to Goethite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conroy, Nathan A.; Zavarin, Mavrik; Kersting, Annie B.

For this research, the effect of citric acid (CA), desferrioxamine B (DFOB), fulvic acid (FA), and humic acid (HA) on plutonium (Pu) sorption to goethite was studied as a function of organic carbon concentration and pH using batch sorption experiments at 5 mg C·L –1 and 50 mg C·L –1 natural organic matter (NOM), 10 –9–10 –10 M 238Pu, and 0.1 g·L –1 goethite concentrations, at pH 3, 5, 7, and 9. Low sorption of ligands coupled with strong Pu complexation decreased Pu sorption at pH 5 and 7, relative to a ligand-free system. Conversely, CA, FA, and HA increasedmore » Pu sorption to goethite at pH 3, suggesting ternary complex formation or, in the case of humic acid, incorporation into HA aggregates. Mechanisms for ternary complex formation were characterized by Fourier transform infrared spectroscopy in the absence of Pu. CA and FA demonstrated clear surface interactions at pH 3, HA appeared unchanged suggesting HA aggregates had formed, and no DFOB interactions were observed. Plutonium sorption decreased in the presence of DFOB (relative to a ligand free system) at all pH values examined. Thus, DFOB does not appear to facilitate formation of ternary Pu-DFOB-goethite complexes. At pH 9, Pu sorption in the presence of all NOM increased relative to pH 5 and 7; speciation models attributed this to Pu(IV) hydrolysis competing with ligand complexation, increasing sorption. In conclusion, the results indicate that in simple Pu-NOM-goethite ternary batch systems, NOM will decrease Pu sorption to goethite at all but particularly low pH conditions.« less

Antigenicity of the 2015-2016 seasonal H1N1 human influenza virus HA and NA proteins.

PubMed

Clark, Amelia M; DeDiego, Marta L; Anderson, Christopher S; Wang, Jiong; Yang, Hongmei; Nogales, Aitor; Martinez-Sobrido, Luis; Zand, Martin S; Sangster, Mark Y; Topham, David J

2017-01-01

Antigenic drift of the hemagglutinin (HA) and neuraminidase (NA) influenza virus proteins contributes to reduced vaccine efficacy. To analyze antigenic drift in human seasonal H1N1 viruses derived from the 2009 pandemic H1N1 virus (pH1N1-like viruses) accounts for the limited effectiveness (around 40%) of vaccination against pH1N1-like viruses during the 2015-2016 season, nasal washes/swabs collected from adult subjects in the Rochester, NY area, were used to sequence and isolate the circulating viruses. The HA and NA proteins from viruses circulating during the 2015-2016 season encoded eighteen and fourteen amino acid differences, respectively, when compared to A/California/04/2009, a strain circulating at the origin of the 2009 pandemic. The circulating strains belonged to subclade 6B.1, defined by HA amino acid substitutions S101N, S179N, and I233T. Hemagglutination-inhibiting (HAI) and HA-specific neutralizing serum antibody (Ab) titers from around 50% of pH1N1-like virus-infected subjects and immune ferrets were 2-4 fold lower for the 2015-2016 circulating strains compared to the vaccine strain. In addition, using a luminex-based mPlex HA assay, the binding of human sera from subjects infected with pH1N1-like viruses to the HA proteins from circulating and vaccine strains was not identical, strongly suggesting antigenic differences in the HA protein. Additionally, NA inhibition (NAI) Ab titers in human sera from pH1N1-like virus-infected subjects increased after the infection and there were measurable antigenic differences between the NA protein of circulating strains and the vaccine strain using both ferret and human antisera. Despite having been vaccinated, infected subjects exhibited low HAI Ab titers against the vaccine and circulating strains. This suggests that poor responses to the H1N1 component of the vaccine as well as antigenic differences in the HA and NA proteins of currently circulating pH1N1-like viruses could be contributing to risk of

Hyaluronic acid for anticancer drug and nucleic acid delivery.

PubMed

Dosio, Franco; Arpicco, Silvia; Stella, Barbara; Fattal, Elias

2016-02-01

Hyaluronic acid (HA) is widely used in anticancer drug delivery, since it is biocompatible, biodegradable, non-toxic, and non-immunogenic; moreover, HA receptors are overexpressed on many tumor cells. Exploiting this ligand-receptor interaction, the use of HA is now a rapidly-growing platform for targeting CD44-overexpressing cells, to improve anticancer therapies. The rationale underlying approaches, chemical strategies, and recent advances in the use of HA to design drug carriers for delivering anticancer agents, are reviewed. Comprehensive descriptions are given of HA-based drug conjugates, particulate carriers (micelles, liposomes, nanoparticles, microparticles), inorganic nanostructures, and hydrogels, with particular emphasis on reports of preclinical/clinical results. Copyright © 2015 Elsevier B.V. All rights reserved.

Neural stem cell proliferation and differentiation in the conductive PEDOT-HA/Cs/Gel scaffold for neural tissue engineering.

PubMed

Wang, Shuping; Guan, Shui; Xu, Jianqiang; Li, Wenfang; Ge, Dan; Sun, Changkai; Liu, Tianqing; Ma, Xuehu

2017-09-26

Engineering scaffolds with excellent electro-activity is increasingly important in tissue engineering and regenerative medicine. Herein, conductive poly(3,4-ethylenedioxythiophene) doped with hyaluronic acid (PEDOT-HA) nanoparticles were firstly synthesized via chemical oxidant polymerization. A three-dimensional (3D) PEDOT-HA/Cs/Gel scaffold was then developed by introducing PEDOT-HA nanoparticles into a chitosan/gelatin (Cs/Gel) matrix. HA, as a bridge, not only was used as a dopant, but also combined PEDOT into the Cs/Gel via chemical crosslinking. The PEDOT-HA/Cs/Gel scaffold was used as a conductive substrate for neural stem cell (NSC) culture in vitro. The results demonstrated that the PEDOT-HA/Cs/Gel scaffold had excellent biocompatibility for NSC proliferation and differentiation. 3D confocal fluorescence images showed cells attached on the channel surface of Cs/Gel and PEDOT-HA/Cs/Gel scaffolds with a normal neuronal morphology. Compared to the Cs/Gel scaffold, the PEDOT-HA/Cs/Gel scaffold not only promoted NSC proliferation with up-regulated expression of Ki67, but also enhanced NSC differentiation into neurons and astrocytes with up-regulated expression of β tubulin-III and GFAP, respectively. It is expected that this electro-active and bio-active PEDOT-HA/Cs/Gel scaffold will be used as a conductive platform to regulate NSC behavior for neural tissue engineering.

Biomedical potential of chitosan/HA and chitosan/β-1,3-glucan/HA biomaterials as scaffolds for bone regeneration--A comparative study.

PubMed

Przekora, Agata; Palka, Krzysztof; Ginalska, Grazyna

2016-01-01

The aim of this work was to compare biomedical potential of chitosan/hydroxyapatite (chit/HA) and novel chitosan/β-1,3-glucan/hydroxyapatite (chit/glu/HA) materials as scaffolds for bone regeneration via characterization of their biocompatibility, porosity, mechanical properties, and water uptake behaviour. Biocompatibility of the scaffolds was assessed in direct-contact with the materials using normal human foetal osteoblast cell line. Cytotoxicity and osteoblast proliferation rate were evaluated. Porosity was assessed using computed microtomography analysis and mechanical properties were determined by compression testing. Obtained results demonstrated that chit/HA scaffold possessed significantly better mechanical properties (compressive strength: 1.23 MPa, Young's modulus: 0.46 MPa) than chit/glu/HA material (compressive strength: 0.26 MPa, Young's modulus: 0.25 MPa). However, addition of bacterial β-1,3-glucan to the chit/HA scaffold improved its flexibility and porosity. Moreover, chit/glu/HA scaffold revealed significantly higher water uptake capability (52.6% after 24h of soaking) compared to the chit/HA (30.7%) and thus can serve as a very good drug delivery carrier. Chit/glu/HA scaffold was also more favourable to osteoblast survival (near 100% viability after 24-h culture), proliferation, and spreading compared to the chit/HA (63% viability). The chit/glu/HA possesses better biomedical potential than chit/HA scaffold. Nevertheless, poor mechanical properties of the chit/glu/HA limit its application to non-load bearing implantation area. Copyright © 2015 Elsevier B.V. All rights reserved.

Construction of surface HA/TiO2 coating on porous titanium scaffolds and its preliminary biological evaluation.

PubMed

Chen, Hongjie; Wang, Chunli; Yang, Xiao; Xiao, Zhanwen; Zhu, Xiangdong; Zhang, Kai; Fan, Yujiang; Zhang, Xingdong

2017-01-01

A simple approach to fabricating hydroxyxapatite/titanium dioxide (HA/TiO 2 ) coating on porous titanium (Ti) scaffolds was developed in the present study. Surface TiO 2 layer was firstly formed on porous Ti scaffolds with multi-scale pores by acid-alkali (AA) treatment. The outer HA layer was then formed on the TiO 2 layer by subsequent pulse electrochemical deposition (ED) technique. All the three main process parameters, i.e. deposition times, current density and mass transfer mode affected the properties of the HA coating notably. Under the conditions of 90 deposition cycles, -10mA/cm 2 of pulse current density and stirring, a thin layer of homogeneous and nanorod-like HA sediments was formed on the substrate surface of porous Ti scaffolds. The results of protein adsorption and cellular experiments showed that compared to the single TiO 2 surface, the HA/TiO 2 surface allowed more adsorption of serum proteins and further enhanced the alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts. Copyright © 2016 Elsevier B.V. All rights reserved.

Virulence of an H5N8 highly pathogenic avian influenza is enhanced by the amino acid substitutions PB2 E627K and HA A149V.

PubMed

Wu, Haibo; Peng, Xiuming; Lu, Rufeng; Xu, Lihua; Liu, Fumin; Cheng, Linfang; Lu, Xiangyun; Yao, Hangping; Wu, Nanping

2017-10-01

A novel reassortant H5N8 highly pathogenic avian influenza (HPAI) virus was recently identified in Asia, Europe, and North America. The H5N8 HPAI virus has raised serious concerns regarding the potential risk for human infection. However, the molecular changes responsible for allowing mammalian infection in H5N8 HPAI viruses are not clear. The objective of this study was to identify amino acid substitutions that are potentially associated with the adaptation of H5N8 HPAI viruses to mammals. In this study, an avian-origin H5N8 virus was adapted to mice through serial lung-to-lung passage. The virulence of mouse-adapted virus was increased and adaptive mutations, HA (A149V) and PB2 (E627K), were detected after the ninth passage in each series of mice. Reverse genetics were used to generate reassortants of the wild type and mouse-adapted viruses. Substitutions in the HA (A149V) and PB2 (E627K) proteins led to enhanced viral virulence in mice, the viruses displayed expanded tissue tropism, and increased replication kinetics in mammalian cells. Continued surveillance in poultry for amino acid changes that might indicate H5N8 HPAI viruses pose a threat to human health is required. Copyright © 2017. Published by Elsevier B.V.

The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin.

PubMed

Kornhauser, Andrija; Wei, Rong-Rong; Yamaguchi, Yuji; Coelho, Sergio G; Kaidbey, Kays; Barton, Curtis; Takahashi, Kaoruko; Beer, Janusz Z; Miller, Sharon A; Hearing, Vincent J

2009-07-01

alpha-Hydroxy acids (alphaHAs) are reported to reduce signs of aging in the skin and are widely used cosmetic ingredients. Several studies suggest that alphaHA can increase the sensitivity of skin to ultraviolet radiation. More recently, beta-hydroxy acids (betaHAs), or combinations of alphaHA and betaHA have also been incorporated into antiaging skin care products. Concerns have also arisen about increased sensitivity to ultraviolet radiation following use of skin care products containing beta-HA. To determine whether topical treatment with glycolic acid, a representative alphaHA, or with salicylic acid, a betaHA, modifies the short-term effects of solar simulated radiation (SSR) in human skin. Fourteen subjects participated in this study. Three of the four test sites on the mid-back of each subject were treated daily Monday-Friday, for a total of 3.5 weeks, with glycolic acid (10%), salicylic acid (2%), or vehicle (control). The fourth site received no treatment. After the last treatment, each site was exposed to SSR, and shave biopsies from all four sites were obtained. The endpoints evaluated in this study were erythema (assessed visually and instrumentally), DNA damage and sunburn cell formation. Treatment with glycolic acid resulted in increased sensitivity of human skin to SSR, measured as an increase in erythema, DNA damage and sunburn cell formation. Salicylic acid did not produce significant changes in any of these biomarkers. Short-term topical application of glycolic acid in a cosmetic formulation increased the sensitivity of human skin to SSR, while a comparable treatment with salicylic acid did not.

HA metabolism in skin homeostasis and inflammatory disease.

PubMed

Kavasi, Rafaela-Maria; Berdiaki, Aikaterini; Spyridaki, Ioanna; Corsini, Emanuela; Tsatsakis, Aristidis; Tzanakakis, George; Nikitovic, Dragana

2017-03-01

Hyaluronan (HA), an unsulfated glycosaminoglycan, is an important component of the complex extracellular matrix network which surrounds and supports cells in tissues. HA is detected in all vertebrate tissues, but the bulk of HA is produced and deposited in the skin. In this review we focus on the role of HA in skin-associated inflammatory disease and wound healing. Properties of HA are directly dependent on its molecular weight. Thus, high molecular weight HA (HMWHA) is deposited in normal tissues during homeostasis and promotes their stability whereas low molecular weight HA fragments (LMWHA), on the other hand, may arise from enzymatic or chemical activities. The degradation of HMWHA to LMWHA fragments, often leads to the generation of biologically active oligosaccharides with different properties and postulated functions in wound scar formation and inflammation. More detailed studies of HA involvement in skin-associated inflammatory disease may result in novel treatment modalities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Complexes of the antimicrobial ciprofloxacin with soil, peat, and aquatic humic substances.

PubMed

Aristilde, Ludmilla; Sposito, Garrison

2013-07-01

Natural organic matter (NOM) is implicated in the binding of antibiotics by particles in soils and waters. The authors' previous computational study revealed structural rearrangement of both hydrophilic and hydrophobic moieties of NOM to favor H-bonding and other intermolecular interactions, as well as both competition with ion-exchange reactions and bridging interactions by NOM-bound divalent cations. The importance of these interactions was investigated using fluorescence-quenching spectroscopy to study the adsorption of ciprofloxacin (Cipro), a fluoroquinolone antibiotic, on 4 reference humic substances (HSs): Elliott soil humic acid (HA), Pahokee peat HA, and Suwannee river HA and fulvic acid. A simple affinity spectrum HS model was developed to characterize the cation-exchange capacity and the amount of H-bond donor moieties as a function of pH. The adsorption results stress the influence of both pH conditions and the type of HS: both soil HA and peat HA exhibited up to 3 times higher sorption capacity than the aquatic HS at pH ≥ 6, normalizing to the aromatic C content accounted for the differences among the terrestrial HS, and increasing the concentration of divalent cations led to a decrease in adsorption on aquatic HA but not on soil HA. In addition, the pH-dependent speciation models of the Cipro-HS complexes illustrate an increase in complexation due to an increase in deprotonation of HS ligands with increasing pH and, at circumneutral and alkaline pH, enhanced complexation of zwitterionic Cipro only in the presence of soil HA and peat HA. The findings of the present study imply that, in addition to electrostatic interactions, van der Waals interactions as facilitated by aromatic structures and H-bond donating moieties in terrestrial HS may facilitate a favorable binding environment. Environ Toxicol Chem 2013;32:1467-1478. © 2013 SETAC. Copyright © 2013 SETAC.

Adsorption of aquatic humic substances on colloidal-size aluminum oxide particles: Influence of solution chemistry

NASA Astrophysics Data System (ADS)

Schlautman, Mark A.; Morgan, James J.

1994-10-01

The adsorption of Suwannee River humic substances (HS) on colloidal-size aluminum oxide particles was examined as a function of solution chemistry. The amount of humic acid (HA) or fulvic acid (FA) adsorbed decreased with increasing pH for all solutions of constant ionic strength. In NaCl solutions at fixed pH values, the adsorption of HA and FA increased with increasing ionic strength. The presence of Ca 2+ enhanced the adsorption of HA but had little effect on FA. For identical solution conditions, the amount (by mass) of HA adsorbed to alumina was always greater than FA. Adsorption densities for both HA and FA showed good agreement with the Langmuir equation, and interpretations of adsorption processes were made from the model parameters. For FA, ligand exchange appears to be the dominant adsorption reaction for the conditions studied here. Ligand exchange is also a major adsorption reaction for HA; however, other reactions contribute to adsorption for some solution compositions. At high pH, cation and water bridging become increasingly important for HA adsorption with increasing amounts of Na + and Ca 2+, respectively. At low to neutral pH values, increases in these same two cations make hydrophobic bonding more effective. Calculations of HS carboxyl group densities in the adsorbed layer support the proposed adsorption reactions. From the adsorption data it appears that fewer than 3.3 HS-COO - groups per nm 2 can be bound directly as inner-sphere complexes by the alumina surface. We propose that the influence of aqueous chemistry on HS adsorption reactions, and therefore on the types of HS surface complexes formed, affects the formation and nature of organic coatings on mineral surfaces.

Nature and chlorine reactivity of organic constituents from reclaimed water in groundwater, Los Angeles County, California

USGS Publications Warehouse

Leenheer, J.A.; Rostad, C.E.; Barber, L.B.; Schroeder, R.A.; Anders, R.; Davisson, M.L.

2001-01-01

The nature and chlorine reactivity of organic constituents in reclaimed water (tertiary-treated municipal wastewater) before, during, and after recharge into groundwater at the Montebello Forebay in Los Angeles County, CA, was the focus of this study. Dissolved organic matter (DOM) in reclaimed water from this site is primarily a mixture of aromatic sulfonates from anionic surfactant degradation, N-acetyl amino sugars and proteins from bacterial activity, and natural fulvic acid, whereas DOM from native groundwaters in the aquifer to which reclaimed water was recharged consists of natural fulvic acids. The hydrophilic neutral N-acetyl amino sugars that constitute 40% of the DOM in reclaimed water are removed during the first 3 m of vertical infiltration in the recharge basin. Groundwater age dating with 3H and 3He isotopes, and determinations of organic and inorganic C isotopes, enabled clear differentiation of recent recharged water from older native groundwater. Phenol structures in natural fulvic acids in DOM isolated from groundwater produced significant trihalomethanes (THM) and total organic halogen (TOX) yields upon chlorination, and these structures also were responsible for the enhanced SUVA and specific fluorescence characteristics relative to DOM in reclaimed water. Aromatic sulfonates and fulvic acids in reclaimed water DOM produced minimal THM and TOX yields.

Topical stabilized retinol treatment induces the expression of HAS genes and HA production in human skin in vitro and in vivo.

PubMed

Li, Wen-Hwa; Wong, Heng-Kuan; Serrano, José; Randhawa, Manpreet; Kaur, Simarna; Southall, Michael D; Parsa, Ramine

2017-05-01

Skin Aging manifests primarily with wrinkles, dyspigmentations, texture changes, and loss of elasticity. During the skin aging process, there is a loss of moisture and elasticity in skin resulting in loss of firmness finally leading to skin sagging. The key molecule involved in skin moisture is hyaluronic acid (HA), which has a significant water-binding capacity. HA levels in skin decline with age resulting in decrease in skin moisture, which may contribute to loss of firmness. Clinical trials have shown that topically applied ROL effectively reduces wrinkles and helps retain youthful appearance. In the current study, ROL was shown to induce HA production and stimulates the gene expression of all three forms of hyaluronic acid synthases (HAS) in normal human epidermal keratinocytes monolayer cultures. Moreover, in human skin equivalent tissues and in human skin explants, topical treatment of tissues with a stabilized-ROL formulation significantly induced the gene expression of HAS mRNA concomitant with an increased HA production. Finally, in a vehicle-controlled human clinical study, histochemical analysis confirmed increased HA accumulation in the epidermis in ROL-treated human skin as compared to vehicle. These results show that ROL increases skin expression of HA, a significant contributing factor responsible for wrinkle formation and skin moisture, which decrease during aging. Taken together with the activity to increase collagen, elastin, and cell proliferation, these studies establish that retinol provides multi-functional activity for photodamaged skin.

Characterization, Corrosion Resistance, and Cell Response of High-Velocity Flame-Sprayed HA and HA/TiO2 Coatings on 316L SS

NASA Astrophysics Data System (ADS)

Singh, Tejinder Pal; Singh, Harpreet; Singh, Hazoor

2012-09-01

The main aim of this study is to evaluate corrosion and biocompatibility behavior of thermal spray hydroxyapatite (HA) and hydroxyapatite/titania bond (HA/TiO2)-coated 316L stainless steel (316L SS). In HA/TiO2 coatings, TiO2 was used as a bond coat between HA top coat and 316L SS substrate. The coatings were characterized by x-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy, and corrosion resistance determined for the uncoated substrate and the two coatings. The biological behavior was investigated by the cell culture studies using osteosarcoma cell line KHOS-NP (R-970-5). The corrosion resistance of the steel was found to increase after the deposition of the HA and HA/TiO2 bond coatings. Both HA, as well as, HA/TiO2 coatings exhibit excellent bond strength of 49 and 47 MPa, respectively. The cell culture studies showed that HA-coated 316L SS specimens appeared more biocompatible than the uncoated and HA/TiO2-coated 316L SS specimens.

Influence of a heptad repeat stutter on the pH-dependent conformational behavior of the central coiled-coil from influenza hemagglutinin HA2.

PubMed

Higgins, Chelsea D; Malashkevich, Vladimir N; Almo, Steven C; Lai, Jonathan R

2014-09-01

The coiled-coil is one of the most common protein structural motifs. Amino acid sequences of regions that participate in coiled-coils contain a heptad repeat in which every third then forth residue is occupied by a hydrophobic residue. Here we examine the consequences of a "stutter," a deviation of the idealized heptad repeat that is found in the central coiled-coil of influenza hemagluttinin HA2. Characterization of a peptide containing the native stutter-containing HA2 sequence, as well as several variants in which the stutter was engineered out to restore an idealized heptad repeat pattern, revealed that the stutter is important for allowing coiled-coil formation in the WT HA2 at both neutral and low pH (7.1 and 4.5). By contrast, all variants that contained idealized heptad repeats exhibited marked pH-dependent coiled-coil formation with structures forming much more stably at low pH. A crystal structure of one variant containing an idealized heptad repeat, and comparison to the WT HA2 structure, suggest that the stutter distorts the optimal interhelical core packing arrangement, resulting in unwinding of the coiled-coil superhelix. Interactions between acidic side chains, in particular E69 and E74 (present in all peptides studied), are suggested to play a role in mediating these pH-dependent conformational effects. This conclusion is partially supported by studies on HA2 variant peptides in which these positions were altered to aspartic acid. These results provide new insight into the structural role of the heptad repeat stutter in HA2. © 2014 Wiley Periodicals, Inc.

Selective pre-priming of HA-specific CD4 T cells restores immunological reactivity to HA on heterosubtypic influenza infection.

PubMed

Alam, Shabnam; Chan, Cory; Qiu, Xing; Shannon, Ian; White, Chantelle L; Sant, Andrea J; Nayak, Jennifer L

2017-01-01

A hallmark of the immune response to influenza is repeated encounters with proteins containing both genetically conserved and variable components. Therefore, the B and T cell repertoire is continually being remodeled, with competition between memory and naïve lymphocytes. Our previous work using a mouse model of secondary heterosubtypic influenza infection has shown that this competition results in a focusing of CD4 T cell response specificity towards internal virion proteins with a selective decrease in CD4 T cell reactivity to the novel HA epitopes. Strikingly, this shift in CD4 T cell specificity was associated with a diminished anti-HA antibody response. Here, we sought to determine whether the loss in HA-specific reactivity that occurs as a consequence of immunological memory could be reversed by selectively priming HA-specific CD4 T cells prior to secondary infection. Using a peptide-based priming strategy, we found that selective expansion of the anti-HA CD4 T cell memory repertoire enhanced HA-specific antibody production upon heterosubtypic infection. These results suggest that the potentially deleterious consequences of repeated exposure to conserved influenza internal virion proteins could be reversed by vaccination strategies that selectively arm the HA-specific CD4 T cell compartment. This could be a potentially useful pre-pandemic vaccination strategy to promote accelerated neutralizing antibody production on challenge with a pandemic influenza strain that contains few conserved HA epitopes.

Simultaneous detection of assembly and disassembly of multivalent HA tag and anti-HA antibody in single in-capillary assay.

PubMed

Wang, Jianhao; Qin, Yuqin; Qin, Haifang; Liu, Li; Ding, Shumin; Teng, Yiwan; Ji, Junling; Qiu, Lin; Jiang, Pengju

2016-08-01

Herein, we have developed an in-capillary assay for simultaneous detection of the assembly and disassembly of the multivalent HA tag peptide and antibody. HA tag with hexahistidine at C terminus (YPYDVPDYAG4 H6 , termed YPYDH6 ) was conjugated with quantum dots (QDs) by metal-affinity force to form a multivalent HA tag (QD-YPYDH6 ). QD-YPYDH6 and monoclonal anti-HA antibody (anti-HA) were sequentially injected into the capillary. They were mixed and assembled inside the capillary. The reaction products were online discriminated and detected by fluorescence coupled capillary electrophoresis (CE-FL). For the in-capillary assay, the binding efficiency of the multivalent HA tag and antibody on was influenced by the molar ratio and injection time. Such novel assay could even give out the self-assembly kinetic constant of QDs and YPYDH6 as KD of 34.1 μM with n (binding cooperativeness) of 2.2 by Hill equation. More importantly, the simultaneous detection of the assembly and imidazole (Im) induced disassembly of the QD-YPYDH6 -anti-HA complex was achieved in a single in-capillary assay. Our study demonstrated a new method for the online detection of antigen-antibody interactions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Water-Glass Coating on HA and HA-TCP Samples for MSCs Adhesion, Proliferation, and Differentiation.

PubMed

Bajpai, Indu; Kim, Duk Yeon; Kyong-Jin, Jung; Song, In-Hwan; Kim, Sukyoung

2016-01-01

Ca-P and silicon based materials have become very popular as bone tissue engineering materials. In this study, water-glass (also known as sodium silicate glass) was coated on sintered hydroxyapatite (HA) and HA-TCP (TCP stands for tricalcium phosphate) samples and subsequently heat-treated at 600°C for 2 hrs. X-rays diffraction showed the presence of β- and α-TCP phases along with HA in the HA-TCP samples. Samples without coating, with water-glass coating, and heat-treated after water-glass coating were used to observe the adhesion and proliferation response of bone marrow derived-mesenchymal stem cells (MSCs). Cell culture was carried out for 4 hrs, 1 day, and 7 days. Interestingly, all samples showed similar response for cell adhesion and proliferation up to 7-day culture but fibronectin, E-cadherin, and osteogenic differentiation related genes (osteocalcin and osteopontin) were significantly induced in heat-treated water-glass coated HA-TCP samples. A water-glass coating on Ca-P samples was not found to influence the cell proliferation response significantly but activated some extracellular matrix genes and induced osteogenic differentiation in the MSCs.

Antigenicity of the 2015–2016 seasonal H1N1 human influenza virus HA and NA proteins

PubMed Central

Anderson, Christopher S.; Wang, Jiong; Yang, Hongmei; Nogales, Aitor; Martinez-Sobrido, Luis; Zand, Martin S.; Sangster, Mark Y.; Topham, David J.

2017-01-01

Antigenic drift of the hemagglutinin (HA) and neuraminidase (NA) influenza virus proteins contributes to reduced vaccine efficacy. To analyze antigenic drift in human seasonal H1N1 viruses derived from the 2009 pandemic H1N1 virus (pH1N1-like viruses) accounts for the limited effectiveness (around 40%) of vaccination against pH1N1-like viruses during the 2015–2016 season, nasal washes/swabs collected from adult subjects in the Rochester, NY area, were used to sequence and isolate the circulating viruses. The HA and NA proteins from viruses circulating during the 2015–2016 season encoded eighteen and fourteen amino acid differences, respectively, when compared to A/California/04/2009, a strain circulating at the origin of the 2009 pandemic. The circulating strains belonged to subclade 6B.1, defined by HA amino acid substitutions S101N, S179N, and I233T. Hemagglutination-inhibiting (HAI) and HA-specific neutralizing serum antibody (Ab) titers from around 50% of pH1N1-like virus-infected subjects and immune ferrets were 2–4 fold lower for the 2015–2016 circulating strains compared to the vaccine strain. In addition, using a luminex-based mPlex HA assay, the binding of human sera from subjects infected with pH1N1-like viruses to the HA proteins from circulating and vaccine strains was not identical, strongly suggesting antigenic differences in the HA protein. Additionally, NA inhibition (NAI) Ab titers in human sera from pH1N1-like virus-infected subjects increased after the infection and there were measurable antigenic differences between the NA protein of circulating strains and the vaccine strain using both ferret and human antisera. Despite having been vaccinated, infected subjects exhibited low HAI Ab titers against the vaccine and circulating strains. This suggests that poor responses to the H1N1 component of the vaccine as well as antigenic differences in the HA and NA proteins of currently circulating pH1N1-like viruses could be contributing to risk of

HaLT2- an enhanced lumber grading trainer

Treesearch

Powsiri Klinkhachorn; Charles Gatchell; Charles McMillin; Ravi Kothari; Dennis Yost

1992-01-01

This paper reports on HaLT2, an improved version of HaLT (Hardwood Lumber Traning Program)- a computer program that provides training in lumber grading. The newly added enhancements In HaLT2 will provide training for both novice and experienced hardwood lumber graders in accordance with National Hardwood Lumber Assodation (NHLA) rules. HaLT2 is more accurate, easier to...

Role of Organic Acids in Bioformation of Kaolinite: Results of Laboratory Experiments

NASA Astrophysics Data System (ADS)

Bontognali, T. R. R.; Vasconcelos, C.; McKenzie, J. A.

2012-04-01

Clay minerals and other solid silica phases have a broad distribution in the geological record and greatly affect fundamental physicochemical properties of sedimentary rocks, including porosity. An increasing number of studies suggests that microbial activity and microbially produced organic acids might play an important role in authigenic clay mineral formation, at low temperatures and under neutral pH conditions. In particular, early laboratory experiments (Linares and Huertas, 1971) reported the precipitation of kaolinite in solutions of SiO2 and Al2O3 with different molar ratios SiO2/Al2O3, together with fulvic acid (a non-characterized mixture of many different acids containing carboxyl and phenolate groups) that was extracted from peat soil. Despite many attempts, these experiments could not be reproduced until recently. Fiore et al. (2011) hypothesized that the non-sterile fulvic acid might have contained microbes that participated in the formation of kaolinite. Using solutions saturated with Si and Al and containing oxalate and/or mixed microbial culture extracted from peat-moss soil, they performed incubation experiments, which produced kaolinite exclusively in solutions containing oxalate and microbes. We proposed to test the role of specific organic acids for kaolinite formation, conducting laboratory experiments at 25˚C, with solutions of sodium silicate, aluminum chloride and various organic compounds (i.e. EDTA, citric acid, succinic acid and oxalic acid). Specific organic acids may stabilize aluminum in octahedral coordination positions, which is crucial for the initial nucleation step. In our experiments, a poorly crystalline mineral that is possibly a kaolinite precursor formed exclusively in the presence of succinic acid. In experiments with other organic compounds, no incorporation of Al was observed, and amorphous silica was the only precipitated phase. In natural environments, succinic acid is produced by a large variety of microbes as an

Role of induced glutathione-S-transferase from Helicoverpa armigera (Lepidoptera: Noctuidae) HaGST-8 in detoxification of pesticides.

PubMed

Labade, Chaitali P; Jadhav, Abhilash R; Ahire, Mehul; Zinjarde, Smita S; Tamhane, Vaijayanti A

2018-01-01

The present study deals with glutathione-S-transferase (GST) based detoxification of pesticides in Helicoverpa armigera and its potential application in eliminating pesticides from the environment. Dietary exposure of a pesticide mixture (organophosphates - chlorpyrifos and dichlorvos, pyrethroid - cypermethrin; 2-15ppm each) to H. armigera larvae resulted in a dose dependant up-regulation of GST activity and gene expression. A variant GST from H. armigera (HaGST-8) was isolated from larvae fed with 10ppm pesticide mixture and it was recombinantly expressed in yeast (Pichia pastoris HaGST-8). HaGST-8 had a molecular mass of 29kDa and was most active at pH 9 at 30°C. GC-MS and LC-HRMS analysis validated that HaGST-8 was effective in eliminating organophosphate type of pesticides and partially reduced the cypermethrin content (53%) from aqueous solutions. Unlike the untransformed yeast, P. pastoris HaGST-8 grew efficiently in media supplemented with pesticide mixtures (200 and 400ppm each pesticide) signifying the detoxification ability of HaGST-8. The amino acid sequence of HaGST-8 and the already reported sequence of HaGST-7 had just 2 mismatches. The studies on molecular interaction strengths revealed that HaGST-8 had stronger binding affinities with organophosphate, pyrethroid, organochloride, carbamate and neonicotinoid type of pesticides. The abilities of recombinant HaGST-8 to eliminate pesticides and P. pastoris HaGST-8 to grow profusely in the presence of high level of pesticide content can be applied for removal of such residues from food, water resources and bioremediation. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of Acid-Base Equilibrium on Absorption Spectra of Humic acid in the Presence of Copper Ions

NASA Astrophysics Data System (ADS)

Lavrik, N. L.; Mulloev, N. U.

2014-03-01

The reaction between humic acid (HA, sample IHSS) and a metal ion (Cu2+) that was manifested as absorption bands in the range 210-350 nm was recorded using absorption spectroscopy. The reaction was found to be more effective as the pH increased. These data were interpreted in the framework of generally accepted concepts about the influence of acid-base equilibrium on the dissociation of salts, according to which increasing the solution pH increases the concentration of HA anions. It was suggested that [HA-Cu2+] complexes formed.

Temperature and magnetic field responsive hyaluronic acid particles with tunable physical and chemical properties

NASA Astrophysics Data System (ADS)

Ekici, Sema; Ilgin, Pinar; Yilmaz, Selahattin; Aktas, Nahit; Sahiner, Nurettin

2011-01-01

We report the preparation and characterization of thiolated-temperature-responsive hyaluronic acid-cysteamine-N-isopropyl acrylamide (HA-CYs-NIPAm) particles and thiolated-magnetic-responsive hyaluronic acid (HA-Fe-CYs) particles. Linear hyaluronic acid (HA) crosslinked with divinyl sulfone as HA particles was prepared using a water-in-oil micro emulsion system which were then oxidized HA-O with NaIO4 to develop aldehyde groups on the particle surface. HA-O hydrogel particles were then reacted with cysteamine (CYs) which interacted with aldehydes on the HA surface to form HA particles with cysteamine (HA-CYs) functionality on the surface. HA-CYs particles were further exposed to radical polymerization with NIPAm to obtain temperature responsive HA-CYs-NIPAm hydrogel particles. To acquire magnetic field responsive HA composites, magnetic iron particles were included in HA to form HA-Fe during HA particle preparation. HA-Fe hydrogel particles were also chemically modified. The prepared HA-CYs-NIPAm demonstrated temperature dependent size variations and phase transition temperature. HA-CYs-NIPAm and HA-Fe-CYs particles can be used as drug delivery vehicles. Sulfamethoxazole (SMZ), an antibacterial drug, was used as a model drug for temperature-induced release studies from these particles.

Influence of humic acid on adsorption of Hg(II) by vermiculite.

PubMed

do Nascimento, Fernando Henrique; Masini, Jorge Cesar

2014-10-01

Geochemical mobility of Hg(II) species is strongly affected by the interactions of these compounds with naturally occurring adsorbents such as humic acids, clay minerals, oxides, etc. Interactions among these sorbents affect their affinity for Hg(II) and a full understanding of these processes is still lacking. The present work describes the influence of a humic acid (HA) sample on the adsorption of Hg(II) by vermiculite (VT). Adsorption isotherms were constructed to evaluate the affinity of Hg(II) by VT, HA, VT modified with humic acid (VT-HA), and VT-HA in presence of soluble humic acid (VT-HA + HA). All experiments were made at pH 6.0 ± 0.1 in 0.02 M NaNO3 and 25.0 ± 0.5 °C for initial Hg(II) concentrations from 1.0 to 100 μM. Determinations of Hg(II) were made by square wave voltammetry automated by sequential injection analysis, an approach that enables the determination of the free plus labile fractions of Hg(II) in HA suspensions without the need for laborious separation steps. The adsorption isotherms were fitted to Langmuir and Freundlich equations, showing that HA was the material with the higher adsorption capacity (537 ± 30 μmol g(-1)) in comparison with VT and VT-HA (44 ± 3 and 51 ± 11 μmol g(-1), respectively). Adsorption order was HA > VT-HA + HA > VT = VT-HA. At pH 6.0 the interaction of HA with VT is weak and only 14% of C initially added to the suspension was effectively retained by the mineral. Desorption of Hg(II) in acidic medium (0.05 M HCl) was higher in binary (VT-HA) and ternary (VT-HA + HA) systems in comparison with that of VT and HA alone, suggesting that interactions between VT and HA are facilitated in acidic medium, weakening the binding to Hg(II). Copyright © 2014 Elsevier Ltd. All rights reserved.

Impact of natural organic matter on arsenic removal by modified granular natural siderite: Evidence of ternary complex formation by HPSEC-UV-ICP-MS.

PubMed

Li, Fulan; Guo, Huaming; Zhou, Xiaoqian; Zhao, Kai; Shen, Jiaxing; Liu, Fei; Wei, Chao

2017-02-01

High arsenic (As) groundwater usually has high concentrations of natural organic matter (NOM). Effects of NOM on arsenic adsorption were investigated to evaluate the efficiency of modified granular natural siderite (MGNS) as an adsorbent for groundwater arsenic remediation. Humic and fulvic acids (HA/FA) were selected as model NOM compounds. In batch tests, HA or FA was either first adsorbed onto the MGNS, or applied together with dissolved arsenic to investigate effects of both adsorbed and dissolved NOM on arsenic removal. The kinetic data showed no significant effects of both adsorbed and dissolved HA/FA on As(III) adsorption. However, As(V) removal was inhibited, whereby the adsorbed NOM compounds had greater inhibitory effect. The inhibitory effect on As(V) removal increased with increasing NOM concentrations. FA exhibited higher inhibitory effect than HA at the same concentration. Steric Exclusion Chromatography-HPLC (SEC-HPLC), and High-Performance Size Exclusion Chromatography-UV-Inductively Coupled Plasma Mass Spectrometry (HPSEC-UV-ICP-MS) revealed that As(V) removal was mostly achieved by the oxyanion adsorption and adversely affected by dissolved FA via competitive adsorption for surface sites. In addition to oxyanion adsorption, removal of As(V) was related to scavenging of ternary HA-As-Fe complexes, which led to the less inhibitory effect of dissolved HA on As(V) removal than dissolved FA via competitive adsorption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced removal of natural organic matters by calcined Mg/Al layered double hydroxide nanocrystalline particles: Adsorption, reusability and mechanism studies

NASA Astrophysics Data System (ADS)

Fang, Liping; Hou, Jingwei; Xu, Cuihong; Wang, Yaru; Li, Ji; Xiao, Feng; Wang, Dongsheng

2018-06-01

Natural organic matters (NOMs) can generate disinfection by-products during water treatment process, threatening to human health. However, the removal of NOM is still unsatisfactory in water treatment. Hence, this work investigated the removal efficiency of humic and fulvic acids (HA and FA) by layered double hydroxide (LDH) and its calcined forms under different conditions. Our results show that calcination of LDH at 500 °C can effectively enhance the NOM removal with adsorption capacities of 98.8 mg/g for HA and 97.6 mg/g for FA at pH 9.5. The removal efficiency of HA and FA notably increases by decreasing pH. The presence of SO42- and CO32- significantly suppresses the removal of HA or FA by CLDHs. The release of Al from LDH and CLDH is negligible and safe to aquatic organisms at pH > 6.5. Moreover, CLDH shows a good reusability for NOM removal in water treatment. The removal of HA and FA by CLDH is governed through electrostatic interactions and intercalation into the interlayers of LDH was not observed. Fluorescence and molecular weight analyses show that the microbial by-products with mid-molecular weight are more difficult to be removed than HA and FA. This study provides a new insight into the NOM removal using LDH and CLDH.

Catalytic Ethanol Dehydration over Different Acid-activated Montmorillonite Clays.

PubMed

Krutpijit, Chadaporn; Jongsomjit, Bunjerd

2016-01-01

In the present study, the catalytic dehydration of ethanol to obtain ethylene over montmorillonite clays (MMT) with mineral acid activation including H2SO4 (SA-MMT), HCl (HA-MMT) and HNO3 (NA-MMT) was investigated at temperature range of 200 to 400°C. It revealed that HA-MMT exhibited the highest catalytic activity. Ethanol conversion and ethylene selectivity were found to increase with increased reaction temperature. At 400°C, the HA-MMT yielded 82% of ethanol conversion having 78% of ethylene yield. At lower temperature (i.e. 200 to 300°C), diethyl ether (DEE) was a major product. The highest activity obtained from HA-MMT can be attributed to an increase of weak acid sites and acid density by the activation of MMT with HCl. It can be also proven by various characterization techniques that in most case, the main structure of MMT did not alter by acid activation (excepted for NA-MMT). Upon the stability test for 72 h during the reaction, the MMT and HA-MMT showed only slight deactivation due to carbon deposition. Hence, the acid activation of MMT by HCl is promising to enhance the catalytic dehydration of ethanol.

Registration of two double rust resistant germplasms, HA-R12 and HA-R13 for confection sunflower

USDA-ARS?s Scientific Manuscript database

The confection sunflower (Helianthus annuus L.) germplasms HA-R12 (Reg. No. ______, PI 673104) and HA-R13 (Reg. No. ______, PI 673105) were developed by the USDA-ARS, Sunflower and Plant Biology Research Unit in collaboration with the North Dakota Agricultural Experiment Station, and released in Jul...

Removal of natural organic matter by titanium tetrachloride: The effect of total hardness and ionic strength.

PubMed

Zhao, Y X; Shon, H K; Phuntsho, S; Gao, B Y

2014-02-15

This study is the first attempt to investigate the effect of total hardness and ionic strength on coagulation performance and the floc characteristics of titanium tetrachloride (TiCl4). Membrane fouling under different total hardness and ionic strength conditions was also evaluated during a coagulation-ultrafiltration (C-UF) hybrid process. Coagulation experiments were performed with two simulated waters, using humic acid (HA, high molecular weight) and fulvic acid (FA, relatively low molecular weight), respectively, as model natural organic matter (NOM). Results show that both particle and organic matter removal can be enhanced by increasing total hardness and ionic strength. Floc characteristics were significantly influenced by total hardness and ionic strength and were improved in terms of floc size, growth rate, strength, recoverability and compactness. The results of the UF tests show that the pre-coagulation with TiCl4 significantly improves the membrane permeate fluxes. Under different total hardness and ionic strength conditions, the membrane permeate flux varied according to both NOM and floc characteristics. The increase in total hardness and ionic strength improved the membrane permeate flux in the case of HA simulated water treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Imaging of Homeostatic, Neoplastic, and Injured Tissues by HA-Based Probes

PubMed Central

Veiseh, Mandana; Breadner, Daniel; Ma, Jenny; Akentieva, Natalia; Savani, Rashmin C; Harrison, Rene; Mikilus, David; Collis, Lisa; Gustafson, Stefan; Lee, Ting-Yim; Koropatnick, James; Luyt, Leonard G.; Bissell, Mina J.; Turley, Eva A.

2013-01-01

An increase in hyaluronan (HA) synthesis, cellular uptake, and metabolism occurs during the remodeling of tissue microenvironments following injury and during disease processes such as cancer. We hypothesized that multimodality HA-based probes selectively target and detectably accumulate at sites of high HA metabolism, thus providing a flexible imaging strategy for monitoring disease and repair processes. Kinetic analyses confirmed favorable available serum levels of the probe following intravenous (i.v.) or subcutaneous (s.c.) injection. Nuclear (technetium-HA, 99mTc-HA, and iodine-HA, 125I-HA), optical (fluorescent Texas Red-HA, TR-HA), and magnetic resonance (gadolinium-HA, Gd-HA) probes imaged liver (99mTc-HA), breast cancer cells/xenografts (TR-HA, Gd-HA), and vascular injury (125I-HA, TR-HA). Targeting of HA probes to these sites appeared to result from selective HA receptor-dependent localization. Our results suggest that HA-based probes, which do not require polysaccharide backbone modification to achieve favorable half-life and distribution, can detect elevated HA metabolism in homeostatic, injured, and diseased tissues. PMID:22066590

Antibacterial Property of Cold-Sprayed HA-Ag/PEEK Coating

NASA Astrophysics Data System (ADS)

Sanpo, Noppakun; Tan, Meng Lu; Cheang, Philip; Khor, K. A.

2009-03-01

The antibacterial behavior of HA-Ag (silver-doped hydroxyapatite) nanopowder and their composite coatings were investigated against Escherichia coli (DH5α). HA-Ag nanopowder and PEEK (poly-ether-ether-ketone)-based HA-Ag composite powders were synthesized using in-house powder processing techniques. Bacteria culture assay of HA-Ag nanopowder and their composite powders displayed excellent bacteriostatic activity against E. coli. The antibacterial activity increased with increasing concentration of HA-Ag nanoparticle in these composite powders. These nanocomposite powders were subsequently used as feedstock to generate antibacterial coatings via cold spray technology. The ratios of HA-Ag to PEEK in their composite powders were 80:20, 60:40, 40:60, and 20:80 (wt.%). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using FESEM/EDX and XRD. Antibacterial nanocomposite HA-Ag/PEEK coatings were successfully deposited using cold spraying parameters of 11-12 bars at preheated air temperature between 150 and 160 °C. These as-sprayed coatings of HA-Ag/PEEK composite powders comprising varying HA-Ag and PEEK ratios retained their inherent antibacterial property as verified from bacterial assay. The results indicated that the antibacterial activity increased with increasing HA-Ag nanopowder concentration in the composite powder feedstock and cold-sprayed coating.

Spectroscopic characterization of DOM and the nitrogen removal mechanism during wastewater reclamation plant.

PubMed

Wang, Lei; Li, Ying-Jun; Xiong, Ying; Tan, Wen-Bing; Zhang, Lie-Yu; Li, Xiang; Wang, Xiao-Shu; Xu, Jian-Feng; Li, Tong-Tong; Wang, Jin-Sheng; Cai, Ming-Xuan; Xi, Bei-Dou; Wang, Di-Hua

2017-01-01

The performance of the Sha-he wastewater reclamation plant was evaluated in this study. To remove residual nitrogen after Anaerobic-Anoxic-Oxic (A2O) treatment, three multistage Anoxic-Oxic (A/O) were added to investigate the nitrogen removal efficiency and its mechanism. In addition, the constituents and evolution of dissolved organic matter (DOM) during wastewater reclamation was also investigated using a method combining fluorescence spectroscopy with fluorescence regional integration (FRI). The results suggested that multistage A/O treatment can effectively improve the nitrogen removal ability under low concentrations of carbon sources. The total nitrogen (TN) exhibits significantly positive correlation with fulvic acid-like materials and humic acid-like materials. The correlation coefficient for TN and fulvic acid-like substances (R2 = 0.810, P < 0.01) removal was greater than that of humic acid-like substances (R2 = 0.636, P < 0.05). The results indicate that nitrogen removal may be achieved with the fulvic-like and humic-like substances, and the removal effects were higher by fulvic acid-like substances than humic-like substances, mostly due to that the latter were relatively more difficult to be utilized as carbon source during the nitrogen removal process. The effluent water quality of biological treatment reached the first grade A standard of "Cities sewage treatment plant pollutant discharge standard" (GB18918-2002). In addition, the effluent from the membrane bioreactor reached the "Standards of reclaimed water quality" (SL368-2006).

Spectroscopic characterization of DOM and the nitrogen removal mechanism during wastewater reclamation plant

PubMed Central

Wang, Lei; Li, Ying-Jun; Xiong, Ying; Tan, Wen-Bing; Zhang, Lie-Yu; Li, Xiang; Wang, Xiao-Shu; Xu, Jian-feng; Li, Tong-Tong; Wang, Jin-Sheng; Cai, Ming-Xuan; Xi, Bei-Dou; Wang, Di-Hua

2017-01-01

The performance of the Sha-he wastewater reclamation plant was evaluated in this study. To remove residual nitrogen after Anaerobic-Anoxic-Oxic (A2O) treatment, three multistage Anoxic-Oxic (A/O) were added to investigate the nitrogen removal efficiency and its mechanism. In addition, the constituents and evolution of dissolved organic matter (DOM) during wastewater reclamation was also investigated using a method combining fluorescence spectroscopy with fluorescence regional integration (FRI). The results suggested that multistage A/O treatment can effectively improve the nitrogen removal ability under low concentrations of carbon sources. The total nitrogen (TN) exhibits significantly positive correlation with fulvic acid-like materials and humic acid-like materials. The correlation coefficient for TN and fulvic acid-like substances (R2 = 0.810, P < 0.01) removal was greater than that of humic acid-like substances (R2 = 0.636, P < 0.05). The results indicate that nitrogen removal may be achieved with the fulvic-like and humic-like substances, and the removal effects were higher by fulvic acid-like substances than humic-like substances, mostly due to that the latter were relatively more difficult to be utilized as carbon source during the nitrogen removal process. The effluent water quality of biological treatment reached the first grade A standard of “Cities sewage treatment plant pollutant discharge standard” (GB18918-2002). In addition, the effluent from the membrane bioreactor reached the “Standards of reclaimed water quality” (SL368-2006). PMID:29149172

Response of humic-reducing microorganisms to the redox properties of humic substance during composting.

PubMed

Zhao, Xinyu; He, Xiaosong; Xi, Beidou; Gao, Rutai; Tan, Wenbing; Zhang, Hui; Huang, Caihong; Li, Dan; Li, Meng

2017-12-01

Humic substance (HS) could be utilized by humus-reducing microorganisms (HRMs) as the terminal acceptors. Meanwhile, the reduction of HS can support the microbial growth. This process would greatly affect the redox conversion of inorganic and organic pollutants. However, whether the redox properties of HS lined with HRMs community during composting still remain unclear. This study aimed to assess the relationships between the redox capability of HS [i.e. humic acids (HA) and fulvic acids (FA)] and HRMs during composting. The results showed that the changing patterns of electron accepting capacity and electron donating capacity of HS were diverse during seven composting. Electron transfer capacities (ETC) of HA was significantly correlated with the functional groups (i.e. alkyl C, O-alkyl C, aryl C, carboxylic C, aromatic C), aromaticity and molecular weight of HA. Aromatic C, phenols, aryl C, carboxylic C, aromaticity and molecular weight of HS were the main structuralfeatures associated with the ETC of FA. Ten key genera of HRMs were found significantly determine these redox-active functional groups of HS during composting, thus influencing the ETC of HS in composts. In addition, a regulating method was suggested to enhance the ETC of HS during composting based on the relationships between the key HRMs and redox-active functional groups as well as environmental variables. Copyright © 2017 Elsevier Ltd. All rights reserved.

Glycosylation of Residue 141 of Subtype H7 Influenza A Hemagglutinin (HA) Affects HA-Pseudovirus Infectivity and Sensitivity to Site A Neutralizing Antibodies.

PubMed

Alvarado-Facundo, Esmeralda; Vassell, Russell; Schmeisser, Falko; Weir, Jerry P; Weiss, Carol D; Wang, Wei

2016-01-01

Human infections with H7 subtype influenza virus have been reported, including an H7N7 outbreak in Netherlands in 2003 and H7N9 infections in China in 2013. Previously, we reported murine monoclonal antibodies (mAbs) that recognize the antigenic site A of H7 hemagglutinin (HA). To better understand protective immunity of H7 vaccines and vaccine candidate selection, we used these mAbs to assess the antigenic relatedness among two H7 HA isolated from past human infections and determine residues that affect susceptibility to neutralization. We found that these mAbs neutralize pseudoviruses bearing HA of A/Shanghai/02/2013(H7N9), but not A/Netherlands/219/2003(H7N7). Glycosylation of the asparagine residue at position 141 (N141) (N133, H3 HA numbering) in the HA of A/Netherlands/219/2003 HA is responsible for this resistance, and it affects the infectivity of HA-pseudoviruses. The presence of threonine at position 143 (T135, H3 HA numbering) in the HA of A/Netherlands/219/2003, rather than an alanine found in the HA of A/Shanghai/02/2013(H7N9), accounts for these differences. These results demonstrate a key role for glycosylation of residue N141 in affecting H7 influenza HA-mediated entry and sensitivity to neutralizing antibodies, which have implications for candidate vaccine design.

[PREPARATION AND BIOCOMPATIBILITY OF IN SITU CROSSLINKING HYALURONIC ACID HYDROGEL].

PubMed

Liang, Jiabi; Li, Jun; Wang, Ting; Liang, Yuhong; Zou, Xuenong; Zhou, Guangqian; Zhou, Zhiyu

2016-06-08

To fabricate in situ crosslinking hyaluronic acid hydrogel and evaluate its biocompatibility in vitro. The acrylic acid chloride and polyethylene glycol were added to prepare crosslinking agent polyethylene glycol acrylate (PEGDA), and the molecular structure of PEGDA was analyzed by Flourier transformation infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy. Hyaluronic acid hydrogel was chemically modified to prepare hyaluronic acid thiolation (HA-SH). And the degree of HA-SH was analyzed qualitatively and quantitatively by Ellman method. HA-SH solution in concentrations ( W/V ) of 0.5%, 1.0%, and 1.5% and PEGDA solution in concentrations ( W/V ) of 2%, 4%, and 6% were prepared with PBS. The two solutions were mixed in different ratios, and in situ crosslinking hyaluronic acid hydrogel was obtained; the crosslinking time was recorded. The cellular toxicity of in situ crosslinking hyaluronic acid hydrogel (1.5% HA-SH and 4% PEGDA mixed) was tested by L929 cells. Meanwhile, the biocompatibility of hydrogel was tested by co-cultured with human bone mesenchymal stem cells (hBMSCs). Flourier transformation infrared spectroscopy showed that most hydroxyl groups were replaced by acrylate groups; 1H nuclear magnetic resonance spectroscopy showed 3 characteristic peaks of hydrogen representing acrylate and olefinic bond at 5-7 ppm. The thiolation yield of HA-SH was 65.4%. In situ crosslinking time of hyaluronic acid hydrogel was 2 to 70 minutes in the PEGDA concentrations of 2%-6% and HA-SH concentrations of 0.5%-1.5%. The hyaluronic acid hydrogel appeared to be transparent. The toxicity grade of leaching solution of hydrogel was grade 1. hBMSCs grew well and distributed evenly in hydrogel with a very high viability. In situ crosslinking hyaluronic acid hydrogel has low cytotoxicity, good biocompatibility, and controllable crosslinking time, so it could be used as a potential tissue engineered scaffold or repairing material for tissue regeneration.

Totally S-protected hyaluronic acid: Evaluation of stability and mucoadhesive properties as liquid dosage form.

PubMed

Pereira de Sousa, Irene; Suchaoin, Wongsakorn; Zupančič, Ožbej; Leichner, Christina; Bernkop-Schnürch, Andreas

2016-11-05

It is the aim of this study to synthesize hyaluronic acid (HA) derivatives bearing mucoadhesive properties and showing prolonged stability at pH 7.4 and under oxidative condition as liquid dosage form. HA was modified by thiolation with l-cysteine (HA-SH) and by conjugation with 2-mercaptonicotinic acid-l-cysteine ligand to obtain an S-protected derivative (HA-MNA). The polymers were characterized by determination of thiol group content and mercaptonicotinic acid content. Cytotoxicity, stability and mucoadhesive properties (rheological evaluation and tensile test) of the polymers were evaluated. HA-SH and HA-MNA could be successfully synthesized with a degree of modification of 5% and 9% of the total moles of carboxylic acid groups, respectively. MTT assay revealed no toxicity for the polymers. HA-SH resulted to be unstable both at pH 7.4 and under oxidative conditions, whereas HA-MNA was stable under both conditions. Rheological assessment showed a 52-fold and a 3-fold increase in viscosity for HA-MNA incubated with mucus compared to unmodified HA and HA-SH, respectively. Tensile evaluation carried out with intestinal and conjunctival mucosa confirmed the higher mucoadhesive properties of HA-MNA compared to HA-SH. According to the presented results, HA-MNA appears to be a potent excipient for the formulation of stable liquid dosage forms showing comparatively high mucodhesive properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

An in vivo evaluation of PLLA/PLLA-gHA nano-composite for internal fixation of mandibular bone fractures.

PubMed

Peng, Weihai; Zheng, Wei; Shi, Kai; Wang, Wangshu; Shao, Ying; Zhang, Duo

2015-11-09

Internal fixation of bone fractures using biodegradable poly(L-lactic-acid) (PLLA)-based materials has attracted the attention of many researchers. In the present study, 36 male beagle dogs were randomly assigned to two groups: PLLA/PLLA-gHA (PLLA-grafted hydroxyapatite) group and PLLA group. PLLA/PLLA-gHA and PLLA plates were embedded in the muscular bags of the erector spinae and also implanted to fix mandibular bone fractures in respective groups. At 1, 2, 3, 6, 9, and 12 months postoperatively, the PLLA/PLLA-gHA and PLLA plates were evaluated by adsorption and degradation tests, and the mandibles were examined through radiographic analysis, biomechanical testing, and histological analysis. The PLLA/PLLA-gHA plates were non-transparent and showed a creamy white color, and the PLLA plates were transparent and faint yellow in color. At all time points following surgery, adsorption and degradation of the PLLA/PLLA-gHA plates were significantly less than those of the PLLA plates, and the lateral and longitudinal bending strengths of the surgically treated mandibles of the beagle dogs in the PLLA/PLLA-gHA group were significantly greater than those of the PLLA group and reached almost the value of intact mandibles at 12 months postoperatively. Additionally, relatively rapid bone healing was observed in the PLLA/PLLA-gHA group with the formation of new lamellar bone tissues at 12 months after the surgery. The PLLA/PLLA-gHA nano-composite can be employed as a biodegradable material for internal fixation of mandibular bone fractures.

Assessing the influence of humic acids on the weathering of galena and its environmental implications.

PubMed

Liu, Qingyou; Li, Heping; Jin, Guoheng; Zheng, Kai; Wang, Luying

2018-08-30

Galena weathering often occurs in nature and releases metal ions during the process. Humic acid (HA), a critical particle of natural organic matter, binds metal ions, thus affecting metal transfer and transformation. In this work, an electrochemical method combined with spectroscopic techniques was adopted to investigate the interfacial processes involved in galena weathering under acidic and alkaline conditions, as well as in the presence of HA. The results show that the initial step of galena weathering involved the transformation Pb 2+ and S°, regardless of whether the solution was acidic or alkaline. Under acidic conditions, S° and Pb 2+ further transform into anglesite, and HA adsorbs on the galena surface, inhibiting the transformation of sulfur. HA and Pb (II) ions form bridging complexes. Under alkaline conditions without HA, the sulfur produced undergoes no transformation, whereas Pb 2+ will transform into PbO. The presence of HA changes the galena weathering mechanism via ionization effect, and Pb 2+ is ultimately converted into anglesite. Higher acidity in acidic conditions or higher alkalinity in alkaline conditions causes galena corrosion when the electrolyte does not contain HA. Conversely, higher pH always accelerates galena corrosion when the electrolyte contains HA, whether the electrolyte is acidic or alkaline. At the same acidity/alkalinity, increasing the concentration of HA inhibits galena weathering. Galena will release 134.7 g m -2 ·y -1 Pb 2+ to solution at pH 2.5, and the amount decreases to 28.09 g m -2 ·y -1 in the presence of 1000 mg/L HA. This study provides an in situ electrochemical method for the assessment of galena weathering. Copyright © 2018 Elsevier Inc. All rights reserved.

Ammonia fixation by humic substances: A nitrogen-15 and carbon-13 NMR study

USGS Publications Warehouse

Thorn, K.A.; Mikita, M.A.

1992-01-01

The process of ammonia fixation has been studied in three well characterized and structurally diverse fulvic and humic acid samples. The Suwannee River fulvic acid, and the IHSS peat and leonardite humic acids, were reacted with 15N-labelled ammonium hydroxide, and analyzed by liquid phase 15N NMR spectrometry. Elemental analyses and liquid phase 13C NMR spectra also were recorded on the samples before and after reaction with ammonium hydroxide. The largest increase in percent nitrogen occurred with the Suwannee River fulvic acid, which had a nitrogen content of 0.88% before fixation and 3.17% after fixation. The 15N NMR spectra revealed that ammonia reacted similarly with all three samples, indicating that the functional groups which react with ammonia exist in structural configurations common to all three samples. The majority of nitrogcn incorporated into the samples appears to be in the form of indole and pyrrole nitrogen, followed by pyridine, pyrazine, amide and aminohydroquinone nitrogen. Chemical changes in the individual samples upon fixation could not be discerned from the 13C NMR spectra.

Presence and potential significance of aromatic-ketone groups in aquatic humic substances

USGS Publications Warehouse

Leenheer, J.A.; Wilson, M.A.; Malcolm, R.L.

1987-01-01

Aquatic humic- and fulvic-acid standards of the International Humic Substances Society were characterized, with emphasis on carbonyl-group nature and content, by carbon-13 nuclear-magnetic-resonance spectroscopy, proton nuclear-magnetic-resonance spectroscopy, and infrared spectroscopy. After comparing spectral results of underivatized humic and fulvic acids with spectral results of chemically modified derivatives, that allow improved observation of the carbonyl group, the data clearly indicated that aromatic ketone groups comprised the majority of the carbonyl-group content. About one ketone group per monocyclic aromatic ring was determined for both humic and fulvic acids. Aromatic-ketone groups were hypothesized to form by photolytic rearrangements and oxidation of phenolic ester and hydrocarbon precursors; these groups have potential significance regarding haloform formation in water, reactivity resulting from active hydrogen of the methyl and methylene adjacent to the ketone groups, and formation of hemiketal and lactol structures. Aromatic-ketone groups also may be the point of attachment between aliphatic and aromatic moieties of aquatic humic-substance structure. ?? 1987.

Changeable HA to improve MIPv6 protocol

NASA Astrophysics Data System (ADS)

Hu, Qing-gui

2015-12-01

For mobile IPv6, home agent (HA) plays an important role. Each mobile node (MN) has a home IP address, it will be not changeable. Also, the home agent (HA) of MN is not changeable. This rule provides the convenient for the ongoing communication without interruption. But it has some obvious drawbacks. Here, the new variable HA scheme is proposed. Every MN has a dynamic cache table, recording the information such as its home address, care-of address, and history address etc. If the accumulated time in one region exceeds that in the hometown, the foreign agent (FA) could become home agent (HA), the home agent could become history agent. Later, the performance of the new protocol is simulated with OPNET software, whose result shows the performance of the new protocol works better than that of the traditional protocol.

Hyaluronic acid-coated, prodrug-based nanostructured lipid carriers for enhanced pancreatic cancer therapy.

PubMed

Lu, Zhihe; Su, Jingrong; Li, Zhengrong; Zhan, Yuzhu; Ye, Decai

2017-01-01

Gemcitabine (GEM) and Baicalein (BCL) are reported to have anti-tumor effects including pancreatic cancer. Hyaluronic acid (HA) can bind to over-expressed receptors in various kinds of cancer cells. The aim of this study is to develop prodrugs containing HA, BCL and GEM, and construct nanomedicine incorporate GEM and BCL in the core and HA on the surface. This system could target the cancer cells and co-deliver the drugs. GEM-stearic acid lipid prodrug (GEM-SA) and hyaluronic acid-amino acid-baicalein prodrug (HA-AA-BCL) were synthesized. Then, GEM and BCL prodrug-based targeted nanostructured lipid carriers (HA-GEM-BCL NLCs) were prepared by the nanoprecipitation technique. The in vitro cytotoxicity studies of the NLCs were evaluated on AsPC1 pancreatic cancer cell line. In vivo anti-tumor effects were observed on the murine-bearing pancreatic cancer model. HA-GEM-BCL NLCs were effective in entering pancreatic cancer cells over-expressing HA receptors, and showed cytotoxicity of tumor cells in vitro. In vivo study revealed significant tumor growth inhibition ability of HA-GEM-BCL NLCs in murine pancreatic cancer model. It could be concluded that HA-GEM-BCL NLCs could be featured as promising co-delivery, tumor-targeted nanomedicine for the treatment of cancers.

Isolation and fractionation of soil humin using alkaline urea and dimethylsulphoxide plus sulphuric acid

NASA Astrophysics Data System (ADS)

Song, Guixue; Hayes, Michael H. B.; Novotny, Etelvino H.; Simpson, Andre J.

2011-01-01

Humin, the most recalcitrant and abundant organic fraction of soils and of sediments, is a significant contributor to the stable carbon pool in soils and is important for the global carbon budget. It has significant resistance to transformations by microorganisms. Based on the classical operational definition, humin can include any humic-type substance that is not soluble in water at any pH. We demonstrate in this study how sequential exhaustive extractions with 0.1 M sodium hydroxide (NaOH) + 6 M urea, followed by dimethylsulphoxide (DMSO) + 6% ( v/ v) sulphuric acid (H2SO4) solvent systems, can extract 70-80% of the residual materials remaining after prior exhaustive extractions in neutral and aqueous basic media. Solid-state 13C NMR spectra have shown that the components isolated in the base + urea system were compositionally similar to the humic and fulvic acid fractions isolated at pH 12.6 in the aqueous media. The NMR spectra indicated that the major components isolated in the DMSO + H2SO4 medium had aliphatic hydrocarbon associated with carboxyl functionalities and with lesser amounts of carbohydrate and peptide and minor amounts of lignin-derived components. The major components will have significant contributions from long-chain fatty acids, waxes, to cuticular materials. The isolates in the DMSO + H2SO4 medium were compositionally similar to the organic components that resisted solvation and remained associated with the soil clays. It is concluded that the base + urea system released humic and fulvic acids held by hydrogen bonding or by entrapment within the humin matrix. The recalcitrant humin materials extracted in DMSO + H2SO4 are largely biological molecules (from plants and the soil microbial population) that are likely to be protected from degradation by their hydrophobic moieties and by sorption on the soil clays. Thus, the major components of humin do not satisfy the classical definitions for humic substances which emphasise that these arise from

Beneficial effects of humic acid on micronutrient availability to wheat

NASA Technical Reports Server (NTRS)

Mackowiak, C. L.; Grossl, P. R.; Bugbee, B. G.

2001-01-01

Humic acid (HA) is a relatively stable product of organic matter decomposition and thus accumulates in environmental systems. Humic acid might benefit plant growth by chelating unavailable nutrients and buffering pH. We examined the effect of HA on growth and micronutrient uptake in wheat (Triticum aestivum L.) grown hydroponically. Four root-zone treatments were compared: (i) 25 micromoles synthetic chelate N-(4-hydroxyethyl)ethylenediaminetriacetic acid (C10H18N2O7) (HEDTA at 0.25 mM C); (ii) 25 micromoles synthetic chelate with 4-morpholineethanesulfonic acid (C6H13N4S) (MES at 5 mM C) pH buffer; (iii) HA at 1 mM C without synthetic chelate or buffer; and (iv) no synthetic chelate or buffer. Ample inorganic Fe (35 micromoles Fe3+) was supplied in all treatments. There was no statistically significant difference in total biomass or seed yield among treatments, but HA was effective at ameliorating the leaf interveinal chlorosis that occurred during early growth of the nonchelated treatment. Leaf-tissue Cu and Zn concentrations were lower in the HEDTA treatment relative to no chelate (NC), indicating HEDTA strongly complexed these nutrients, thus reducing their free ion activities and hence, bioavailability. Humic acid did not complex Zn as strongly and chemical equilibrium modeling supported these results. Titration tests indicated that HA was not an effective pH buffer at 1 mM C, and higher levels resulted in HA-Ca and HA-Mg flocculation in the nutrient solution.

Registration of two confection sunflower germplasm Lines, HA-R10 and HA-R11, Resistant to sunflower rust

USDA-ARS?s Scientific Manuscript database

Two confection sunflower (Helianthus annuus L.) germplasm lines, HA-R10 (Reg. No.xxx, PI670043) and HA-R11 (Reg. No.xxx, PI670044) were developed by the USDA-ARS Sunflower and Plant Biology Research Unit in collaboration with the North Dakota Agricultural Experiment Station and released December, 20...

The role of amino acids in hydroxyapatite mineralization

PubMed Central

2016-01-01

Polar and charged amino acids (AAs) are heavily expressed in non-collagenous proteins (NCPs), and are involved in hydroxyapatite (HA) mineralization in bone. Here, we review what is known on the effect of single AAs on HA precipitation. Negatively charged AAs, such as aspartic acid, glutamic acid (Glu) and phosphoserine are largely expressed in NCPs and play a critical role in controlling HA nucleation and growth. Positively charged ones such as arginine (Arg) or lysine (Lys) are heavily involved in HA nucleation within extracellular matrix proteins such as collagen. Glu, Arg and Lys intake can also increase bone mineral density by stimulating growth hormone production. In vitro studies suggest that the role of AAs in controlling HA precipitation is affected by their mobility. While dissolved AAs are able to inhibit HA precipitation and growth by chelating Ca2+ and PO43− ions or binding to nuclei of calcium phosphate and preventing their further growth, AAs bound to surfaces can promote HA precipitation by attracting Ca2+ and PO43− ions and increasing the local supersaturation. Overall, the effect of AAs on HA precipitation is worth being investigated more, especially under conditions closer to the physiological ones, where the presence of other factors such as collagen, mineralization inhibitors, and cells heavily influences HA precipitation. A deeper understanding of the role of AAs in HA mineralization will increase our fundamental knowledge related to bone formation, and could lead to new therapies to improve bone regeneration in damaged tissues or cure pathological diseases caused by excessive mineralization in tissues such as cartilage, blood vessels and cardiac valves. PMID:27707904

Characterization of humic substances in landfill leachate and impact on the hydraulic conductivity of geosynthetic clay liners.

PubMed

Han, Young-Soo; Lee, Jai-Young; Miller, Carol J; Franklin, Lance

2009-05-01

A detailed characterization was performed on the humic substances present in landfill leachate derived from the older (10-year) and younger (6-month) municipal landfill cells at a site in Inchion, Korea. The characterization focused on the humic and fulvic acid components of the leachate, relying on information gleaned from the UV/visible spectroscopy, molecular weight distribution, and Fourier transform infrared spectroscopy. The effect of the leachates, and specific components of the leachates, on the hydraulic conductivity of a geosynthetic clay liner (GCL), was evaluated. The humic acid extracted from the older leachate was composed primarily of high molecular weight and aromatic compounds, which is typical for humic acids. However, the humic acid extracted from the younger leachate showed characteristics more similar with fulvic acids, indicating that the younger humic acid was at the initial stage of humification. The hydraulic conductivity of the GCLs to the humic and fulvic acids of the older and younger leachate was similar to those permeated with the distilled deionized water (DI). However, the hydraulic conductivity of the samples tested with the raw leachate was more than 200 times the DI value. This fact suggests that cations present in leachate, rather than humic substances, are the key factor in the increase of the permeability.

Putative suppressing effect of IgG Fc-conjugated haemagglutinin (HA) stalk of influenza virus H7N9 on the neutralizing immunogenicity of Fc-conjugated HA head: implication for rational design of HA-based influenza vaccines.

PubMed

He, B; Xia, S; Yu, F; Fu, Y; Li, W; Wang, Q; Lu, L; Jiang, S

2016-02-01

The emergence of influenza A H7N9 in infection has posed a great threat to public health globally. Poor immunogenicity of H7N9 haemagglutinin (HA) is a major obstacle to the development of an effective H7N9 vaccine. Here, we found that the vaccine containing the H7HA head conjugated with IgG Fc (Hd-Fc) induced strong neutralizing antibody responses and protection against H7N9 infection, whilst the Fc-conjugated H7HA stalk (St-Fc)-based vaccine could not induce neutralizing antibodies, although the St-Fc-immunized mice were partially protected. The vaccines containing the full-length extracellular domain of HA conjugated with Fc and the mixture of Hd-Fc plus St-Fc induced significantly lower neutralizing antibody and haemagglutination inhibition titres than the Hd-Fc-based vaccine. These results suggest that the St-Fc may have inhibitory effects on the neutralizing immunogenicity of Hd-Fc. Therefore, the neutralizing domain(s), such as the receptor-binding domain, in the HA head should be kept and the non-neutralizing domain(s) in the HA stalk with the ability to potentially suppress the neutralizing immunogenicity of HA head should be removed from Fc-conjugated HA-based influenza vaccines to increase the neutralizing antibody response.

Humic Acids Enhanced U(VI) Attenuation in Acidic Waste Plumes: An In-situ Remediation Approach

NASA Astrophysics Data System (ADS)

Wan, J.; Dong, W.; Tokunaga, T. K.

2010-12-01

In the process of extracting plutonium for nuclear weapons production during the Cold War, large volumes of acidic waste solutions containing low-level radionuclides were discharged for decades into unlined seepage basins in several US Department of Energy (DOE) weapon facilities such as the Savannah River Site (SRS), Oak Ridge (OR), and 300 Area of the Hanford Site. Although the basins have been capped and some sites have gone through many years of active remediation, groundwaters currently remain acidic with pH values as low as 3.0 near the basins, and uranium concentrations remain much higher than its maximum contaminant level (MCL). A sustainable U biogeochemical remediation method has not yet been developed, especially under acidic conditions (pH 3-5). Bioreduction-based U remediation requires permanent maintenance of reducing conditions through indefinite supply of electron donor, and when applied in acidic plumes a high-cost pretreatment procedure is required. Methods based on precipitation of phosphate minerals depend on maintenance of high P concentrations. Precipitating of uranyl vanadates can lower U to below its MCL, but this approach is only effective at near-neutral pH. There is an urgent need for developing a sustainable method to control U mobility in acidic conditions. In this paper, we propose a method of using humic acids (HAs) to attenuate contaminant U mobility in acidic waste plumes. Our laboratory experiment results show that HAs are able to strongly and quickly adsorb onto aquifer sediments from the DOE’s SRS and OR. With a moderate addition of HA, U adsorption increased to near 100% at pH below 5.0. Because U partitioning onto the HA modified mineral surfaces is so strong, U concentration in groundwaters can be sustainably reduced to below its MCL. We conducted flow through experiments for U desorption by acidic groundwater leaching at pH 3.5 and 4.5 from HA-treated SRS contaminated sediments. The results show that desorption of both U

Potential of capillary zone electrophoresis for estimation of humate acid-base properties.

PubMed

Vanifatova, Natalia G; Zavarzina, Anna G; Spivakov, Boris Ya

2008-03-07

Capillary zone electrophoresis (CZE) has been applied for fractionation and characterization of soil-derived humic acids (HAs). Humic acids from soddy-podzolic (HA(s)) and chernozem (HA(ch)) soils were studied as well as hydrophobic high-molecular-weight (HMW) and hydrophilic low-molecular-weight (LMW) HA(s) fractions obtained by salting-out with ammonium sulfate at a saturation of 0-40% and >70%, respectively. The possibility of CZE partial fractionation of HAs has been demonstrated. The shape of "humic hump" was shown to depend on the pH of running electrolyte. Almost the whole peak overlapping occurred if alkaline solutions were used for fractionation, but the peak resolution was improved at pH 5-7. Under appropriate fractionation conditions (pH 7), at least three humic acid subfractions with different electrophoretic mobilities were distinguished in the electropherograms of initial HA and HA(s) fractions. Such a high peak resolution has never been achieved for humic acids before. The presence of three subfractions in the HA is in agreement with gel-filtration analysis and was confirmed by comparison of the electrophoretic behavior of HA(s) with those of its HMW (hydrophobic) and the LMW (hydrophilic) fractions. The potentiometric titration of HA and its fractions was performed and the pK(a) of the functional groups were calculated. An attempt was made for the first time to relate the variation of electrophoretic mobility values with acid-base properties of humic acids. It was shown that changes in the humate charge resulting from the variation of the ionization degree of its functional groups as a function of pH can be estimated on the basis of electrophoretic mobility values. Potential of CZE in estimation of HA isoelectric point was demonstrated. The pH value corresponding to the lowest absolute electrophoretic mobility value of about 20 x 10(-5) cm(2) V(-1) s(-1) can be used for approximate estimation of HA isoelectric point. The data were discussed and

Particle size, charge and colloidal stability of humic acids coprecipitated with Ferrihydrite.

PubMed

Angelico, Ruggero; Ceglie, Andrea; He, Ji-Zheng; Liu, Yu-Rong; Palumbo, Giuseppe; Colombo, Claudio

2014-03-01

Humic acids (HA) have a colloidal character whose size and negative charge are strictly dependent on surface functional groups. They are able to complex large amount of poorly ordered iron (hydr)oxides in soil as a function of pH and other environmental conditions. Accordingly, with the present study we intend to assess the colloidal properties of Fe(II) coprecipitated with humic acids (HA) and their effect on Fe hydroxide crystallinity under abiotic oxidation and order of addition of both Fe(II) and HA. TEM, XRD and DRS experiments showed that Fe-HA consisted of Ferrihydrite with important structural variations. DLS data of Fe-HA at acidic pH showed a bimodal size distribution, while at very low pH a slow aggregation process was observed. Electrophoretic zeta-potential measurements revealed a negative surface charge for Fe-HA macromolecules, providing a strong electrostatic barrier against aggregation. Under alkaline conditions HA chains swelled, which resulted in an enhanced stabilization of the colloid particles. The increasing of zeta potential and size of the Fe-HA macromolecules, reflects a linear dependence of both with pH. The increase in the size and negative charge of the Fe-HA precipitate seems to be more affected by the ionization of the phenolic acid groups, than by the carboxylic acid groups. The main cause of negative charge generation of Fe/HA is due to increased dissociation of phenolic groups in more expanded structure. The increased net negative surface potential induced by coprecipitation with Ferrihydrite and the correspondent changes in configuration of the HA could trigger the inter-particle aggregation with the formation of new negative surface. The Fe-HA coprecipitation can reduce electrosteric repulsive forces, which in turn may inhibit the aggregation process at different pH. Therefore, coprecipitation of Ferrihydrite would be expected to play an important role in the carbon stabilization and persistence not only in organic soils, but

Inhibition of hydroxyl radical reaction with aromatics by dissolved natural organic matter

USGS Publications Warehouse

Lindsey, M.E.; Tarr, M.A.

2000-01-01

Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compound molecules bound to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H2O2 + Fe2+ ??? Fe3+ + HO- + HO??). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanism for the observed inhibition is that hydroxyl radical formation occurs in microenvironmental sites remote from the aromatic compounds. In addition to changes in kinetics, pyrene hydroxyl radical reaction also exhibited a mechanistic change in the presence of fulvic acid. The mechanism changed from a reaction that was apparently firstorder in pyrene to one that was apparently secondorder in pyrene, indicating that pyrene self-reaction may have become the dominant mechanism in the presence of fulvic acid. Dissolved NOM causes significant changes in the rate and mechanism of hydroxyl radical degradation of aromatic compounds. Consequently, literature rate constants measured in pure water will not be useful for predicting the degradation of pollutants in environmental systems. The kinetic and mechanistic information in this study will be useful for developing improved degradation methods involving Fenton chemistry.Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compounds molecules bounds to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H2O2 + Fe2+ ??? Fe3+ + HO- + HO??). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanisms for the observed inhibition is that hydroxyl radical

2-Hydroxy Acids in Plant Metabolism

PubMed Central

Maurino, Veronica G.; Engqvist, Martin K. M.

2015-01-01

Glycolate, malate, lactate, and 2-hydroxyglutarate are important 2-hydroxy acids (2HA) in plant metabolism. Most of them can be found as D- and L-stereoisomers. These 2HA play an integral role in plant primary metabolism, where they are involved in fundamental pathways such as photorespiration, tricarboxylic acid cycle, glyoxylate cycle, methylglyoxal pathway, and lysine catabolism. Recent molecular studies in Arabidopsis thaliana have helped elucidate the participation of these 2HA in in plant metabolism and physiology. In this chapter, we summarize the current knowledge about the metabolic pathways and cellular processes in which they are involved, focusing on the proteins that participate in their metabolism and cellular/intracellular transport in Arabidopsis. PMID:26380567

A Crosslinked HA-Based Hydrogel Ameliorates Dry Eye Symptoms in Dogs

PubMed Central

Williams, David L.; Mann, Brenda K.

2013-01-01

Keratoconjunctivitis sicca, commonly referred to as dry eye or KCS, can affect both humans and dogs. The standard of care in treating KCS typically includes daily administration of eye drops to either stimulate tear production or to hydrate and lubricate the corneal surface. Lubricating eye drops are often applied four to six times daily for the life of the patient. In order to reduce this dosing regimen yet still provides sufficient hydration and lubrication, we have developed a crosslinked hydrogel based on a modified, thiolated hyaluronic acid (HA), xCMHA-S. This xCMHA-S gel was found to have different viscosity and rheologic behavior than solutions of noncrosslinked HA. The gel was also able to increase tear breakup time in rabbits, indicating a stabilization of the tear film. Further, in a preliminary clinical study of dogs with KCS, the gel significantly reduced the symptoms associated with KCS within two weeks while only being applied twice daily. The reduction of symptoms combined with the low dosing regimen indicates that this gel may lead to both improved patient health and owner compliance in applying the treatment. PMID:23840213

Chlorination of humic materials: Byproduct formation and chemical interpretations

USGS Publications Warehouse

Reckhow, D.A.; Singer, P.C.; Malcolm, R.L.

1990-01-01

Ten aquatic humic and fulvic acids were isolated and studied with respect to their reaction with chlorine. Yields of TOX, chloroform, trichloroacetic acid, dichloroacetic acid, dichloroacetonitrile, and 1,1,1-trichloropropanone were measured at pH 7 and 12. Humic acids produced higher concentrations than their corresponding fulvic acids of all byproducts except 1,1,1-trichloropropanone. Chlorine consumption and byproduct formation were related to fundamental chemical characteristics of the humic materials. A statistical model was proposed for activated aromatic content based on 13C NMR and base titration data. The values estimated from this model were found to be well correlated with chlorine consumption. Specific byproduct formation was related to UV absorbance, nitrogen content, or the activated aromatic content. ?? 1990 American Chemical Society.

An injectable oxidated hyaluronic acid/adipic acid dihydrazide hydrogel as a vitreous substitute.

PubMed

Su, Wen-Yu; Chen, Ko-Hua; Chen, Yu-Chun; Lee, Yen-Hsien; Tseng, Ching-Li; Lin, Feng-Huei

2011-01-01

Vitrectomy is a common procedure for treating ocular-related diseases. The surgery involves removing the vitreous humor from the center of the eye, and vitreous substitutes are needed to replace the vitreous humor after vitrectomy. In the present study, we developed a colorless, transparent and injectable hydrogel with appropriate refractive index as a vitreous substitute. The hydrogel is formed by oxidated hyaluronic acid (oxi-HA) cross-linked with adipic acid dihydrazide (ADH). Hyaluronic acid (HA) was oxidized by sodium periodate to create aldehyde functional groups, which could be cross-linked by ADH. The refractive index of this hydrogel ranged between 1.3420 and 1.3442, which is quite similar to human vitreous humor (1.3345). The degradation tests demonstrated that the hydrogel could maintain the gel matrix over 35 days, depending on the ADH concentration. In addition, the cytotoxicity was evaluated on retina pigmented epithelium (RPE) cells cultivated following the ISO standard (tests for in vitro cytotoxicity), and the hydrogel was found to be non-toxic. In a preliminary animal study, the oxi-HA/ADH hydrogel was injected into the vitreous cavity of rabbit eyes. The evaluations of slit-lamp observation, intraocular pressure, cornea thickness and histological examination showed no significant abnormal biological reactions for 3 weeks. This study suggests that the injectable oxi-HA/ADH hydrogel should be a potential vitreous substitute. Koninklijke Brill NV, Leiden, 2011

Temporal changes in soil bacterial diversity and humic substances degradation in subarctic tundra soil.

PubMed

Park, Ha Ju; Chae, Namyi; Sul, Woo Jun; Lee, Bang Yong; Lee, Yoo Kyung; Kim, Dockyu

2015-04-01

Humic substances (HS), primarily humic acids (HA) and fulvic acids (FA), are the largest constituent of soil organic matter. In microcosm systems with subarctic HS-rich tundra soil (site AK 1-75; approximately 5.6 °C during the thawing period) from Council, Alaska, the HA content significantly decreased to 48% after a 99-day incubation at 5 °C as part of a biologically mediated process. Accordingly, levels of FA, a putative byproduct of HA degradation, consistently increased to 172% during an identical incubation process. Culture-independent microbial community analysis showed that during the microcosm experiments, the relative abundance of phyla Proteobacteria (bacteria) and Euryarchaeota (archaea) largely increased, indicating their involvement in HS degradation. When the indigenous bacteria in AK 1-75 were enriched in an artificial mineral medium spiked with HA, the changes in relative abundance were most conspicuous in Proteobacteria (from 60.2 to 79.0%), specifically Betaproteobacteria-related bacteria. One hundred twenty-two HA-degrading bacterial strains, primarily from the genera Paenibacillus (phylum Firmicutes) and Pseudomonas (class Gammaproteobacteria), were cultivated from AK 1-75 and nearby sites. Through culture-dependent analysis with these bacterial isolates, we observed increasing HS-degradation rates in parallel with rising temperatures in a range of 0 °C to 20 °C, with the most notable increase occurring at 8 °C compared to 6 °C. Our results indicate that, although microbial-mediated HS degradation occurs at temperature as low as 5 °C in tundra ecosystems, increasing soil temperature caused by global climate change could enhance HS degradation rates. Extending the thawing period could also increase degradation activity, thereby directly affecting nearby microbial communities and rhizosphere environments.

Selenium fractions in organic matter from Se-rich soils and weathered stone coal in selenosis areas of China.

PubMed

Qin, Hai-bo; Zhu, Jian-ming; Su, Hui

2012-02-01

A high degree of association between Selenium (Se) and organic matter has been demonstrated in natural environments, but Se fractions and speciation in organic matter is unclear. In this study, a method for quantifying organic matter associated with Se (OM-Se) was developed to investigate Se fractions in organic matter in Se-rich soils and weathered stone coal from Enshi, China, where Se poisoning of humans and livestock has been documented. Initially, Se was extracted using water and a phosphate buffer. Subsequently, OM-Se was extracted using NaOH, and then speciated into Se associated with fulvic acids (FA-Se) and humic acids (HA-Se). Both FA-Se and HA-Se were further speciated into the weakly bound and strongly bound fractions using a customized hydride generation reactor. The results show that FA-Se (1.91-479 mg kg(-1)) is the predominant form of Se in all Se-rich soils and the weathered stone coal samples, accounting for more than 62% of OM-Se (3.07-484 mg kg(-1)). Weakly bound FA-Se (1.33-450 mg kg(-1)) was prevalent in the total FA-Se, while weakly bound HA-Se (0.62-26.2 mg kg(-1)) was variable in the total HA-Se (1.15-32.5 mg kg(-1)). These data indicate that OM-Se could play a significant source and sink role in the biogeochemical cycling of Se in the supergene environment. Weakly bound FA-Se seems to act as a potential source for bioavailable Se, whereas strongly bound HA-Se is a possible OM-Se sink which is not readily transformed into bioavailable Se. Copyright © 2011 Elsevier Ltd. All rights reserved.

Antidiabetics and diuretics show phototoxicity in HaCaT cells

NASA Astrophysics Data System (ADS)

Selvaag, Edgar; Petersen, Anita B.; Gniadecki, Robert; Thorn, Tine; Wulf, Hans Christian

2001-10-01

The antidiabetics tolbutamide, glibenclamide, and glipizide, and the diuretics bendroflumethiazide, butizide, furosemide, hydrochlorothiazide, and trichlormethiazide were investigated for potential phototoxicity in the HaCaT cell line. The cells were incubated with the drugs and then exposed to UVA1 irradiation. The effects of the antioxidants L-ascorbic acid, and (alpha) -tocopherol on oxidative DNA damage were assessed. Bendroflumethiazide, furosemide, hydrochlorothiazide, trichlormethiazide, or tolbutamide induced dose-dependent phototoxicity. Cells incubated with bendroflumethiazide, tolbutamide, and glibenclamide, and irradiated with UVA1 demonstrated an increased oxidative DNA damage. Pre-treatment with L-ascorbic acid, or (alpha) -tocopherol, suppressed the UVA-induced DNA damage in cells incubated with 1 mM of bendroflumethiazide, furosemide, glibenclamide, glipizide, tolbutamide, and trichloromethiazide, further implying the involvement of reactive oxygen species in the phototoxic DNA damage. These results may indicate a link between phototoxic and photocancerogenic potential of the sulfonamide-derived oral antidiabetic and diuretic drugs, as it has previously been recognized for psoralen, chlorpromazine, and fluoroquinolones. Excessive exposure to UV light may be deleterious for patients treated with these drugs.

Preparation and characterization of bio-composite PEEK/nHA

NASA Astrophysics Data System (ADS)

Jin, Y. S.; Bian, C. C.; Zhang, Z. Q.; Zhao, Y.; Yang, L.

2017-01-01

PEEK/nHA composite material, with excellent mechanical property as polyetheretherketone (PEEK) and biological activity as hydroxyapatite (HA), has attracted wide attention of medical experts and materials science experts. The addition of hydroxyapatite was the decisive factor for biological activity in PEEK/nHA composite. In this paper, acicular nanohydroxyapatite was prepared by chemical precipitation method with Ca(NO3)2, (NH4)2HPO4 as raw material; PEEK/nHA composite was prepared by solution blending and vacuum sintering method. The composite was characterized with FT-IR, XRD, DSC, TG and mechanical property test. Results showed that the composite has good thermal stability and compressive property when the mass ratio of PEEK to nHA is 10:3; and high nHA content can improve the biological activity of the composite, which can meet the basic requirements for bone tissue engineering scaffold.

Efficacy and safety of injection with poly-L-lactic acid compared with hyaluronic acid for correction of nasolabial fold: a randomized, evaluator-blinded, comparative study.

PubMed

Hyun, M Y; Lee, Y; No, Y A; Yoo, K H; Kim, M N; Hong, C K; Chang, S E; Won, C H; Kim, B J

2015-03-01

Hyaluronic acid (HA) fillers and poly-L-lactic acid (PLA) fillers are frequently used to correct facial wrinkles. To compare the efficacy and safety of a novel injectable poly-L-lactic acid (PLA) filler and a well-studied biphasic HA filler for the treatment of moderate to severe nasolabial folds. In this multicentre, randomized, evaluator-blinded, comparative study, subjects were randomized for injections with PLA or HA into both nasolabial folds. Efficacy was determined by calculating the change in Wrinkle Severity Rating Scale (WSRS) relative to baseline. Local safety was assessed by reported adverse events. At week 24, mean improvement in WSRS from baseline was 2.09 ± 0.68 for the PLA side and 1.54 ± 0.65 for the HA side. Both injections were well tolerated, and the adverse reactions were mild and transient in most cases. PLA provides noninferior efficacy compared with HA 6 months after being used to treat moderate to severe nasolabial folds. © 2014 British Association of Dermatologists.

Hyaluronan/Tannic Acid Nanoparticles Via Catechol/Boronate Complexation as a Smart Antibacterial System.

PubMed

Montanari, Elita; Gennari, Arianna; Pelliccia, Maria; Gourmel, Charlotte; Lallana, Enrique; Matricardi, Pietro; McBain, Andrew J; Tirelli, Nicola

2016-12-01

Nanoparticles based on hyaluronic acid (HA) are designed to deliver tannic acid (TA) as an antimicrobial agent. The presence of HA makes these particles potentially useful to target bacteria that colonize cells presenting HA membrane receptors (e.g. CD44), such as macrophages. HA bearing 3-aminophenyl boronic acid groups (HA-APBA) is reacted with TA, yielding nanoparticles with a size that decreases with decreasing HA molecular weight (e.g. 200 nm for 44 kDa, 400 nm for 737 kDa). The boronate esters make the nanoparticles stable at physiological pH, but their hydrolysis in an acidic environment (pH = 5) leads to swelling/solubilization, therefore potentially allowing TA release in endosomal compartments. We have assessed the nanoparticle toxicity profile (on RAW 264.7 macrophages) and their antimicrobial activity (on E. coli and on both methicillin-sensitive and -resistant S. aureus). The antibacterial effect of HA-APBA/TA nanoparticles was significantly higher than that of TA alone, and has very similar activity to TA coformulated with a reducing agent (ascorbic acid), which indicates both the nanoparticles to protect TA catechols from oxidation, and the effective release of TA after nanoparticle internalization. Therefore, there is potential for these nanoparticles to be used in stable, effective, and potentially targetable nanoparticle-based antimicrobial formulations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of natural aquatic humic substances on the photodegradation of estrone.

PubMed

Silva, Carla Patrícia; Lima, Diana L D; Groth, Milena B; Otero, Marta; Esteves, Valdemar I

2016-02-01

Photodegradation of estrone (E1) was investigated under simulated solar radiation in absence and presence of the different fractions of humic substances (HS), namely humic acids (HA), fulvic acids (FA) and XAD-4 fraction. The pseudo-first order photodegradation rate constants increased from 0.1137 h(-1), in ultrapure (MQ) water, to 0.1774, 0.1943 and 0.3109 h(-1), in presence of HA, FA and XAD-4, respectively. Half-life time decreased from 6.10 h in MQ water to 3.91, 3.57 and 2.23 h in presence of HA, FA and XAD-4, respectively. These results evidence the relevant photosensitizing effect of XAD-4 fraction of HS on the degradation of E1, which, to the best of our knowledge have never been studied. Photodegradation studies were also conducted in organic matter-rich environmental aquatic matrices, namely fresh, estuarine and waste water. After 2 h, photodegradation achieved values ranged between 35.6 and 57.1% in natural water samples, compared with 26.4% in ultrapure water. The higher photodegradation occurred in an estuarine water sample, known to be rich in XAD-4 fraction and poor in HA, indicating that not only the presence of organic matter, but also its type, are determinant in the E1 photodegradation rate. Finally, the use of sodium azide as singlet oxygen ((1)O2) scavenger during the phototransformation of E1 in ultrapure and in two wastewater samples allowed to conclude that (1)O2 has an important role in the E1 photodegradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Changes in Soil Microbial Community and Its Effect on Carbon Sequestration Following Afforestation on the Loess Plateau, China.

PubMed

Xiang, Yun; Cheng, Man; Huang, Yimei; An, Shaoshan; Darboux, Frédéric

2017-08-22

Afforestation plays an important role in soil protection and ecological restoration. The objective of this study is to understand the effect of afforestation on soil carbon and soil microbial communities in the Loess Plateau of China. We measured two chemically-separated carbon fractions (i.e., humic acid, HA, and fulvic acid, FA) and soil microbial communities within shrublands (18-year-old Caragana korshinskii Kom (shrubland I) and 28-year-old Caragana korshinskii Kom (shrubland II)) and cropland. The size and structure of the soil microbial community was measured by phospholipid fatty acid (PLFA) analysis. The analysis of C-fractions indicated that at a depth of 0-20 cm, FA-C concentration in shrubland I and shrubland II were 1.7 times that of cropland, while HA-C had similar values across all three sites. Total PLFAs, G⁺ (Gram positive) bacterial, G - (Gram negative) bacterial, and actinobacterial PLFAs were highest in shrubland II, followed by shrubland I and finally cropland. Fungal PLFAs were significantly higher in shrubland II compared to the other sites. Additionally, we found a high degree of synergy between main microbial groups (apart from fungi) with FA-C. We concluded that planting C. korshinskii in abandoned cropland could alter the size and structure of soil microbial community, with these changes being closely related to carbon sequestration and humus formation.

Changes in Soil Microbial Community and Its Effect on Carbon Sequestration Following Afforestation on the Loess Plateau, China

PubMed Central

Xiang, Yun; Huang, Yimei; An, Shaoshan; Darboux, Frédéric

2017-01-01

Afforestation plays an important role in soil protection and ecological restoration. The objective of this study is to understand the effect of afforestation on soil carbon and soil microbial communities in the Loess Plateau of China. We measured two chemically-separated carbon fractions (i.e., humic acid, HA, and fulvic acid, FA) and soil microbial communities within shrublands (18-year-old Caragana korshinskii Kom (shrubland I) and 28-year-old Caragana korshinskii Kom (shrubland II)) and cropland. The size and structure of the soil microbial community was measured by phospholipid fatty acid (PLFA) analysis. The analysis of C-fractions indicated that at a depth of 0–20 cm, FA-C concentration in shrubland I and shrubland II were 1.7 times that of cropland, while HA-C had similar values across all three sites. Total PLFAs, G+ (Gram positive) bacterial, G− (Gram negative) bacterial, and actinobacterial PLFAs were highest in shrubland II, followed by shrubland I and finally cropland. Fungal PLFAs were significantly higher in shrubland II compared to the other sites. Additionally, we found a high degree of synergy between main microbial groups (apart from fungi) with FA-C. We concluded that planting C. korshinskii in abandoned cropland could alter the size and structure of soil microbial community, with these changes being closely related to carbon sequestration and humus formation. PMID:28829374

Influence of insertion site of the avian influenza virus haemagglutinin (HA) gene within the Newcastle disease virus genome on HA expression.

PubMed

Ramp, Kristina; Skiba, Martin; Karger, Axel; Mettenleiter, Thomas C; Römer-Oberdörfer, Angela

2011-02-01

Members of the order Mononegavirales express their genes in a transcription gradient from 3' to 5'. To assess how this impacts on expression of a foreign transgene, the haemagglutinin (HA) of highly pathogenic avian influenza virus (HPAIV) A/chicken/Vietnam/P41/05 (subtype H5N1) was inserted between the phosphoprotein (P) and matrix protein (M), M and fusion protein (F), or F and haemagglutinin-neuraminidase protein (HN) genes of attenuated Newcastle disease virus (NDV) Clone 30. In addition, the gene encoding the neuraminidase of HPAIV A/duck/Vietnam/TG24-01/05 (subtype H5N1) was inserted into the NDV genome either alone or in combination with the HA gene. All recombinants replicated well in embryonated chicken eggs. The expression levels of HA-specific mRNA and protein were quantified by Northern blot analysis and mass spectrometry, with good correlation. HA expression levels differed only moderately and were highest in the recombinant carrying the HA insertion between the F and HN genes of NDV.

Osteoinductive-nanoscaled silk/HA composite scaffolds for bone tissue engineering application.

PubMed

Huang, Xiaowei; Bai, Shumeng; Lu, Qiang; Liu, Xi; Liu, Shanshan; Zhu, Hesun

2015-10-01

Osteoinductive silk/hydroxyapatite (HA) composite scaffolds for bone regeneration were prepared by combining silk with HA/silk core-shell nanoparticles. The HA/silk nanoparticles were directly dispersed in silk solution to form uniform silk/HA blend and then composite scaffolds after a freeze-drying process. The HA/silk nanoparticles uniformly distributed in silk scaffolds at nanometer scale at varying HA content up to 40%, and substantially improved the compressive strength of the scaffolds produced. Rat bone mesenchymal stem cells (rBMSCs) were cultured in these scaffolds and cell proliferation was analyzed by confocal microscopy and DNA assay. Gene expression and biochemical assays were employed to study the influence of increasing HA/silk nanoparticles on in vitro osteogenic differentiation of rBMSCs. Increasing HA/silk nanoparticles inside silk scaffolds improved the growth and osteogenic capability of rBMSCs in the absence of osteogenic growth factors, and also significantly increased the calcium and collagen I deposition. In addition, compared to silk/HA composite scaffolds containing HA aggregates, the scaffolds loaded with HA/silk nanoparticles showed remarkably higher stiffness and better osteogenic property at same HA content, implying a preferable microenvironment for rBMSCs. These results suggest that the osteogenic property as well as mechanical property of silk/HA scaffolds could be further improved through fabricating their structure and topography at nanometer scale, providing more suitable systems for bone regeneration. © 2014 Wiley Periodicals, Inc.

The change of organic matter in sewage sludge composting and its influence on the adsorption of pentachlorophenol (PCP).

PubMed

Liping, Lou; Defu, Liu; Huanyu, Chen; Fang, Chen; Yunfeng, He; Guangming, Tian

2015-04-01

Due to the abundance of organic matter in compost, the addition of compost to soil can promote the adsorption of pesticides. However, few studies have examined the influence of the composting duration on the organic matter (OM) transformation and adsorption capacity of the compost. In this study, a mixture of sewage sludge and straw was composted, and then the physicochemical properties of various OM were studied. Additionally, the sorption capacities of humic acid (HA), humin (HM), humic acid + humin, and fulvic acid (FA) + humic acid + humin extracted from composts of different stages toward pentachlorophenol (PCP) were compared. The sorption data can be well-described by the Freundlich model, and the sorption capacity of PCP on HM is the strongest of all organic components. After 120 days of composting, the sorption abilities of HA and HM increased by 54.76 and 36.73%, respectively, which corresponds with increases in the aromatization degree, BET specific area, and pore volume and with a decrease in acid functional groups. The sorption ability of HA and HM increased by 54.76 and 36.73% due to the increase of the aromatization degree. However, the sorption capacity of the compost decreased by 51.2%, which resulted from a decrease in total organic matter content and from the interaction between organic components in composts. This could be verified by the sequence of the sorption capacity: HM > HM + HA > HM + HA + FA > HA. The contribution of humus to the sorption of PCP onto compost is approximately 41 to 55%, and it increases with composting time. Therefore, it is possible that other components are present that affect the adsorption of PCP on composts.

Fluorescence excitation-emission matrix spectroscopy analysis of landfill leachate DOM in coagulation-flocculation process.

PubMed

Zhu, Guocheng; Wang, Chuang; Dong, Xingwei

2017-06-01

Landfill leachate contains a variety of organic matters, some of which can be excited and emit fluorescence signal. In order to degrade these organic matters, the pretreatment of the leachate is needed, which can improve the degradation performance of post-treatment process. Coagulation-flocculation is one of the important pretreatment processes to treat landfill leachate. Assessing the chemical compositions of landfill leachate is helpful in the understanding of their sources and fates as well as the mechanistic behaviors in the water environment. The present work aimed to use fluorescence excitation-emission matrix spectroscopy (EEMs) to characterize the chemical fractions of landfill leachate dissolved organic matter (DOM) in conjunction with parallel factor analysis (PARAFAC). Results showed that the DOM of landfill leachate tested in this study was identified resulting from microbial input, which included five typical characteristic peaks and four kinds of PARAFAC fractions. These fractions were mainly composed of hydrophobic macromolecule humic acid-like (HM-HA), hydrophilic intermediate molecular fulvic acid-like (HIM-FA), and hydrophilic small molecule protein-like substances (HSM-PS). HM-HA and HIM-FA were found to be easier to remove than HSM-PS. Further research on HSM-PS removal by coagulation-flocculation still needs to be improved.

[Analysis of soil humus and components after 26 years' fertilization by infrared spectroscopy method].

PubMed

Zhang, Yu-Lan; Sun, Cai-Xia; Chen, Zhen-Hua; Li, Dong-Po; Liu, Xing-Bin; Chen, Li-Jun; Wu, Zhi-Jie; Du, Jian-Xiong

2010-05-01

The infrared spectrum was used to discuss structure change of soil humus and components of chemical groups in soil humic acids (HA) and fulvic acids (FA) isolated from soils in different fertilization treatment after 26 year's fertilization. The result indicated that using the infrared spectroscopy method for the determination of humus, humus fractions (HA and FA) and their structure is feasible. Fertilization affected the structure and content of soil humus and aromatization degree. After 26 years' fertilization, the infrared spectrum shapes with different treatments are similar, but the characteristic peak intensity is obviously different, which reflects the effects of different fertilization treatments on the structure and amounts of soil humus or functional groups. Compared with no fertilization, little molecule saccharides decreased and aryl-groups increased under application of inorganic fertilizer or combined application of organic and chemical fertilizer. The effect was greater in Treatment NPK and M+NPK than in Treatment M1 N and M2 N. Organic and NPK fertilizer increased the development of soil and increased soil quality to a certain extent. Results showed that organic fertilization increased aromatization degree of soil humus and humus fractions distinctly. The authors could estimate soil humus evolvement of different fertilization with infrared spectroscopy.

Evaluation of monitoring indicators for the post-closure care of a landfill for MSW characterized with low lignin content.

PubMed

Zheng, Wei; Lü, Fan; Bolyard, Stephanie C; Shao, Liming; Reinhart, Debra R; He, Pinjing

2015-02-01

To understand the applicability of the termination indicators for landfill municipal solid waste (MSW) with low initial lignin content, four different accelerated landfill stabilization techniques were applied to anaerobic landfilled waste, including anaerobic flushing with water, anaerobic flushing with Fenton-treated leachate, and aerobic flushing with Fenton-treated and UV/H2O2-treated leachate. Termination indicators, including total organic carbon (TOC), ammonia-N (NH4(+)-N), the ratio of UV absorbance at 254 nm to TOC concentration (SUVA254), fluorescence spectra of leachate, methane production, oxygen consumption, lignocellulose content, and humus-like content were evaluated. Results suggest that oxygen consumption related indicators used as a termination indicator for low-lignin-content MSW were more sensitive than methane consumption related indicators. Aeration increased humic acid (HA) and (HA+FA)/HyI content by 2.9 and 1.7 times compared to the anaerobically stabilized low-lignin-content MSW. On the other hand, both the fulvic acid (FA) and hydrophilic (HyI) fractions remained constant regardless of stabilization technique. The target value developed for low-lignin-content MSW was quite different than developed countries mainly due to low residual biodegradable organic carbon content in stabilized low-lignin-content MSW. Copyright © 2014 Elsevier Ltd. All rights reserved.

Impact of the Interaction between Aquatic Humic Substances and Algal Organic Matter on the Fouling of a Ceramic Microfiltration Membrane.

PubMed

Zhang, Xiaolei; Fan, Linhua; Roddick, Felicity A

2018-02-01

The influence of the interaction between aquatic humic substances and the algal organic matter (AOM) derived from Microcystis aeruginosa on the fouling of a ceramic microfiltration (MF) membrane was studied. AOM alone resulted in a significantly greater flux decline compared with Suwannee River humic acid (HA), and fulvic acid (FA). The mixture of AOM with HA and FA exhibited a similar flux pattern as the AOM alone in the single-cycle filtration tests, indicating the flux decline may be predominantly controlled by the AOM in the early filtration cycles. The mixtures resulted in a marked increase in irreversible fouling resistance compared with all individual feed solutions. An increase in zeta potential was observed for the mixtures (becoming more negatively charged), which was in accordance with the increased reversible fouling resistance resulting from enhanced electrostatic repulsion between the organic compounds and the negatively-charged ceramic membrane. Dynamic light scattering (DLS) and size exclusion chromatography analyses showed an apparent increase in molecular size for the AOM-humics mixtures, and some UV-absorbing molecules in the humics appeared to participate in the formation of larger aggregates with the AOM, which led to greater extent of pore plugging and hence resulted in higher irreversible fouling resistance.

Impact of the Interaction between Aquatic Humic Substances and Algal Organic Matter on the Fouling of a Ceramic Microfiltration Membrane

PubMed Central

Zhang, Xiaolei; Fan, Linhua

2018-01-01

The influence of the interaction between aquatic humic substances and the algal organic matter (AOM) derived from Microcystis aeruginosa on the fouling of a ceramic microfiltration (MF) membrane was studied. AOM alone resulted in a significantly greater flux decline compared with Suwannee River humic acid (HA), and fulvic acid (FA). The mixture of AOM with HA and FA exhibited a similar flux pattern as the AOM alone in the single-cycle filtration tests, indicating the flux decline may be predominantly controlled by the AOM in the early filtration cycles. The mixtures resulted in a marked increase in irreversible fouling resistance compared with all individual feed solutions. An increase in zeta potential was observed for the mixtures (becoming more negatively charged), which was in accordance with the increased reversible fouling resistance resulting from enhanced electrostatic repulsion between the organic compounds and the negatively-charged ceramic membrane. Dynamic light scattering (DLS) and size exclusion chromatography analyses showed an apparent increase in molecular size for the AOM-humics mixtures, and some UV-absorbing molecules in the humics appeared to participate in the formation of larger aggregates with the AOM, which led to greater extent of pore plugging and hence resulted in higher irreversible fouling resistance. PMID:29389873

High strength yttria-reinforced HA scaffolds fabricated via honeycomb ceramic extrusion.

PubMed

Elbadawi, M; Shbeh, M

2018-01-01

The present study investigated the effects of hydroxyapatite (HA) reinforced with yttria on porous scaffolds fabricated via honeycomb ceramic extrusion. Yttria was selected as it has been demonstrated to toughen other ceramics. Moreover, yttria has been surmised to suppress dehydroxylation in HA, a characteristic that prefigures decomposition thereof during sintering into mechanically weaker phases. However, the compressive strength of yttria-reinforced hydroxyapatite (Y-HA) porous scaffolds has hitherto not been reported. Y-HA was synthesised by calcining a commercially available HA with 10wt% yttria at 1000°C. Y-HA was then fabricated into porous scaffolds using an in-house honeycomb extruder, and subsequently sintered at 1200 and 1250°C. The results were compared to the uncalcined as-received commercial powder (AR-HA) and calcined pure HA powder at 1000°C (C-HA). It was discovered that calcination alone caused marked improvements to the stoichiometry, thermal stability, porosity and compressive strength of scaffolds. The improvements were ascribed to the calcined powders with less susceptibility to both agglomeration and enhanced densification. Still, differences were observed between C-HA and Y-HA at 1250°C. The compressive strength increased from 105.9 to 127.3MPa, a larger microporosity was descried and the HA matrix in Y-HA was more stoichiometric. The latter was confirmed by XRD and EDS analyses. Therefore, it was concluded that the reinforcing of hydroxyapatite with yttria improved the compressive strength and suppressed dehydroxylation of porous HA scaffolds. In addition, the compressive strength achieved demonstrated great potential for load-bearing application. Copyright © 2017 Elsevier Ltd. All rights reserved.

Variations of Escherichia coli O157:H7 Survival in Purple Soils

PubMed Central

Zhang, Taoxiang; Hu, Suping; Yang, Wenhao

2017-01-01

Escherichia coli O157:H7 is a well-recognized cause of human illness. Survival of Escherichia coli O157:H7 in five purple soils from Sichuan Province was investigated. The dynamics of E. coli O157:H7 survival in purple soils were described by the Weibull model. Results showed that this model is suitable to fit survival curves of E. coli O157:H7 in purple soils, with the calculated td value (survival time needed to reach the detection limit of 100 CFU·g−1) ranging from 2.99 days to 26.36 days. The longest survival time of E. coli O157:H7 was observed in neutral purple soils (24.49 days), followed by alkalescent purple soil (18.62 days) and acid purple soil (3.48 days). The redundancy analysis (RDA) revealed that td values were significantly enhanced by soil nutrition (total organic carbon (OC), total nitrogen (TN), available potassium (AK) and the ratio of humic acid to fulvic acid (Ha/Fa)), but were significantly suppressed by iron and aluminum oxide. PMID:29057845

Hyaluronic Acid (HA) Scaffolds and Multipotent Stromal Cells (MSCs) in Regenerative Medicine.

PubMed

Prè, Elena Dai; Conti, Giamaica; Sbarbati, Andrea

2016-12-01

Traditional methods for tissue regeneration commonly used synthetic scaffolds to regenerate human tissues. However, they had several limitations, such as foreign body reactions and short time duration. In order to overcome these problems, scaffolds made of natural polymers are preferred. One of the most suitable and widely used materials to fabricate these scaffolds is hyaluronic acid. Hyaluronic acid is the primary component of the extracellular matrix of the human connective tissue. It is an ideal material for scaffolds used in tissue regeneration, thanks to its properties of biocompatibility, ease of chemical functionalization and degradability. In the last few years, especially from 2010, scientists have seen that the cell-based engineering of these natural scaffolds allows obtaining even better results in terms of tissue regeneration and the research started to grow in this direction. Multipotent stromal cells, also known as mesenchymal stem cells, plastic-adherent cells isolated from bone marrow and other mesenchymal tissues, with self-renew and multi-potency properties are ideal candidates for this aim. Normally, they are pre-seeded onto these scaffolds before their implantation in vivo. This review discusses the use of hyaluronic acid-based scaffolds together with multipotent stromal cells, as a very promising tool in regenerative medicine.

Chemical and biological characterization of organic matter during composting of municipal solid waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chefetz, B.; Yona Chen; Hadar, Y.

Composting of municipal solid waste (MSW) was studied in an attempt to elaborate transformations of organic matter (OM) during the process and define parameters for the degree of maturity of the product. Composting was performed in 1-m{sup 3} plastic boxes and the following parameters were measured in 13 samples during 132 d of composting: temperature, C/N ratio, ash content, humic substance contents, and fractions (humic acid, fulvic acid, and nonbumic fraction-HA, FA and NHF, respectively). Spectroscopic methods (CPMAS {sup 13}C-NMR, DRIFT) were used to study the chemical composition of the OM. A bioassay based on growth of cucumber (Cucumis satifusmore » L. cv. Dlila) plants was correlated to other parameters. The C/N ratio and ash content showed a typical high rate of change during the first 60 d and reached a plateau thereafter. The HA content increased to a maximum at 112 d, corresponding to the highest plant dry weight and highest 1650/1560 (cm{sup {minus}1}/cm{sup {minus}1}) peak ratios calculated from DRIFT spectra. {sup 13}C-NMR and DRIFT spectra of samples taken from the composting MSW during the process showed that the residual OM contained an increasing level of aromatic structures. Plant-growth bioassay, HA content, and the DRIFT spectra indicated that MSW compost described in this study, stabilized and achieved maturity after about 110 d. 31 refs., 8 figs., 2 tabs.« less

Role of membrane fouling substances on the rejection of N-nitrosamines by reverse osmosis.

PubMed

Fujioka, Takahiro; Kodamatani, Hitoshi; Aizawa, Hidenobu; Gray, Stephen; Ishida, Kenneth P; Nghiem, Long D

2017-07-01

The impact of fouling substances on the rejection of four N-nitrosamines by a reverse osmosis (RO) membrane was evaluated by characterizing individual organic fractions in a secondary wastewater effluent and deploying a novel high-performance liquid chromatography-photochemical reaction-chemiluminescence (HPLC-PR-CL) analytical technique. The HPLC-PR-CL analytical technique allowed for a systematic examination of the correlation between the fouling level and the permeation of N-nitrosamines in the secondary wastewater effluent and synthetic wastewaters through an RO membrane. Membrane fouling caused by the secondary wastewater effluent led to a notable decrease in the permeation of N-nitrosodimethylamine (NDMA) while a smaller but nevertheless discernible decrease in the permeation of N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR) and N-nitrosomorpholine (NMOR) was also observed. Fluorescence spectrometry analysis revealed that major foulants in the secondary wastewater effluent were humic and fulvic acid-like substances. Analysis using the size exclusion chromatography technique also identified polysaccharides and proteins as additional fouling substances. Thus, further examination was conducted using solutions containing model foulants (i.e., sodium alginate, bovine serum albumin, humic acid and two fulvic acids). Similar to the secondary wastewater effluent, membrane fouling with fulvic acid solutions resulted in a decrease in N-nitrosamine permeation. In contrast, membrane fouling with the other model foulants resulted in a negligible impact on N-nitrosamine permeation. Overall, these results suggest that the impact of fouling on the permeation of N-nitrosamines by RO is governed by specific small organic fractions (e.g. fulvic acid-like organics) in the secondary wastewater effluent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioconcentration of perfluoroalkyl substances by Chironomus plumosus larvae in water with different types of dissolved organic matters.

PubMed

Wen, Wu; Xia, Xinghui; Chen, Xi; Wang, Haotian; Zhu, Baotong; Li, Husheng; Li, Yang

2016-06-01

The effects of four types of dissolved organic matters (DOM) on the bioconcentration of perfluoroalkyl substances (PFASs) in Chironomus plumosus larvae have been studied. The PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA). The DOM included humic acid (HA), fulvic acid (FA), tannic acid (TA), and a protein, peptone (PEP), and their concentrations ranged from 0 to 50 mg L(-1). The results showed that, upon bioconcentration equilibrium, the body burdens of longer perfluoroalkyl chain PFASs (PFOS, PFDA, PFUnA and PFDoA) decreased with PEP and HA concentrations while increased with FA and TA concentrations. When FA and TA concentrations increased from 0 to 50 mg L(-1), body burdens of these PFASs increased by 7.5%-148.8% and 5.7%-37.1%, respectively. However, the DOM had no significant impact on the body burdens of shorter perfluoroalkyl chain PFASs (PFOA and PFNA). All of the four types of DOM lowered not only the uptake rate constants (ku) of PFASs due to the decrease of freely dissolved PFAS concentrations, but also the elimination rate constants (ke) due to the inhibition effect of DOM on the PFAS elimination from the larvae. The reduction in the two constants varied with both DOM and PFAS types. In the presence of PEP and HA with larger molecular weights, the ku values decreased more than ke, leading to the decreased body burdens of longer perfluoroalkyl chain PFASs. As for FA and TA with smaller molecular weights, the ke values decreased more than ku, resulting in increased body burdens of longer perfluoroalkyl chain PFASs. This study suggests that the effects of DOM on PFAS bioconcentration depend not only on the concentration but also on the molecule weight of DOM, which should be considered in the bioavailability assessment of PFASs. Copyright © 2016 Elsevier Ltd. All rights reserved.

EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid.

PubMed

Kanchana, P; Sekar, C

2014-09-01

Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142 nM over a wide concentration range from 1 × 10(-7) to 3 × 10(-5)M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples. Copyright © 2014. Published by Elsevier B.V.

Limitations in the use of commercial humic acids in water and soil research

USGS Publications Warehouse

Malcolm, R.L.; MacCarthy, P.

1986-01-01

Seven samples of commercial "humic acids", purchased from five different suppliers, were studied, and their characteristics were compared with humic and fulvic acids isolated from streams, soils, peat, leonardite, and a dopplerite sample. Cross-polarization and magic-angle spinning 13C NMR spectroscopy clearly shows pronounced differences between the commercial materials and all other samples. Elemental and infrared spectroscopic data do not show such clear-cut differences but can be used as supportive evidence, with the 13C NMR data, to substantiate the above distinctions. As a result of these differences and due to the general lack of information relating to the source, method of isolation, or other pretreatment of the commercial materials, these commercial products are not considered to be appropriate for use as analogues of true soil and water humic substances, in experiments designed to evaluate the nature and reactivity of humic substances in natural waters and soils.

Transport features of nano-hydroxylapatite (n-HA) embedded silicone rubber (SR) systems: influence of SR/n-HA interaction, degree of reinforcement and morphology.

PubMed

M, Bindu; G, Unnikrishnan

2017-09-27

We report the transport characteristics of silicone rubber/nano-hydroxylapatite (SR/n-HA) systems at room temperature with reference to the effects of n-HA loading, morphology and penetrant nature, using toluene, xylene, ethyl acetate and butyl acetate in the liquid phase and methanol, ethanol, 1-propanol, 2-propanol and butanol in the vapour phase as probe molecules. The interaction between the n-HA particles and SR matrix has been confirmed by FTIR analysis. As the n-HA content in the SR matrix increased, the penetrant uptake has been found to decrease. The observations have been correlated with the density and void content of the systems. Scanning electron microscopy images have been found to be complementary to the observed transport features. The reinforcement effect of n-HA particles on the SR matrix has been verified by Kraus equation. Molecular mass between the cross links has been observed to decrease with an increase in n-HA loading. The results have been compared with affine, phantom network, parallel, series and Maxwell models. The transport data have been complemented by observations on biological fluid uptake with urea, d-glucose, KI, saline water, phosphate buffer and artificial urine as the media.

Experimental Study of Fouling Behavior of Main Substances (BSA, HA, SA) of Dissolved Organic Matter (DOM) in Dead-end Membrane Filtration

NASA Astrophysics Data System (ADS)

Sun, Yongjun; Zhu, Kexin; Khan, Bushra; Du, Xinpei; Hou, Lei; Zhao, Shuang; Li, Ping; Liu, Songbai; Song, Peng; Zhang, Hong; Jiang, Shuihong; Wang, Zhan; Zha, Shenghua

2018-01-01

In this study, the fouling behavior of PES ultrafiltration (UF) membrane with different DOM fractions including bovine serum albumin (BSA), sodium alginate (SA) and humic acid (HA) was systematically investigated. The result showed that the fouling mechanism of HA was cake formation while that of BSA and SA was caused by both pore blocking and cake formation due to the different particle size. Moreover, membrane fouling became more severe with the increase of feed concentration and TMP and it could be accurately described by the cake-complete model. The pore blocking resistance for SA was larger than that for BSA, whereas the cake resistance followed the sequence SA>BSA>HA. This observation offered insight into the differences in fouling behavior of the various DOM components and was further used as guidance for practical application.

[Mitigating the repress of cinnamic acid to cucumber growth by microbial strain].

PubMed

Yu, Guo-hui; Xie, Yin-hua; Chen, Yan-hong; Chen, Yuan-feng; Cheng, Ping

2006-12-01

Cucumber is one of the most important vegetable species. Its continuous planting has become a common practice demand in many areas of China, but an obstacle from continuous planting made sustainable production of this crop to be prohibited. The self-toxic effect was considered as an important negative factor to continuous cropping cucumber. And cinnamic acid was found to be the main substance to cause self-toxic. Strain Ha8, which isolated from waste water estuary in Zhuhai city and has been authenticated as Cellulosimicrobium cellulans, was found to be able to degrade cinnamic acid, benzoic acid, paraaminobenzoic acid and phenol. Its biologic degrading rate to cinnamic acid was 64.1% and its total degrading rate to cinnamic acid was 79.32% . Therefore, strain Ha8 was used to mitigate the growth stress of cucumber caused by cinnamic acid in the research. In the experiment by hydroponic culturing method, it was found that the stem length, root length, stem weight, leaf weight, root weight, numbers of flower and harvest weight of cucumbers were lower than those untreated ones when added 2micromol/L or 10micromol/L cinnamic acid in culturing solution. But when added 10(7)cfu/L of strain Ha8 and 2micromol/L or 10micromol/L cinnamic acid in same culturing solution, these parameters were higher than those treated only by 2mircomol/L or 10micromol/L cinnamic acid. The result shown that strain Ha8 could mitigate the self-toxic effect caused by cinnamic acid. In edaphic culturing experiments, it was found that organic fertilizer mixed with strain Ha8 could mitigate the growth stress of cucumber caused by 100mg/kg cinnamic acid. When added 3mg/kg sterilized organic fertilizer with strain Ha8 (> or = 10(6)cfu/g dry organic fertilizer) in the culturing soil, the result was satisfied. This treatment could not only improve the growth of cucumber, enhance their root dehydrogenase activity and output, promote their nutrition absorption rate, but also adjust the microbial groups in

Hyaluronic acid: its role in voice.

PubMed

Ward, P Daniel; Thibeault, Susan L; Gray, Steven D

2002-09-01

The extracellular matrix (ECM), once regarded simply as a structural scaffold, is now recognized as an important modulator of cellular behavior and function. One component that plays a prominent role in this process is hyaluronic acid (HA)--a molecule found in many different tissues. Research into the roles of HA indicates that it plays a key role in tissue viscosity, shock absorption, and space filling. Specifically, research into the role of HA in laryngology indicates that it has profound effects on the structure and viscosity of vocal folds. This article provides an introduction to the structure and biological functions of HA and its importance in voice. In addition, an overview of the pharmaceutical applications of HA is discussed.

Stalking influenza by vaccination with pre-fusion headless HA mini-stem.

PubMed

Valkenburg, Sophie A; Mallajosyula, V Vamsee Aditya; Li, Olive T W; Chin, Alex W H; Carnell, George; Temperton, Nigel; Varadarajan, Raghavan; Poon, Leo L M

2016-03-07

Inaccuracies in prediction of circulating viral strain genotypes and the possibility of novel reassortants causing a pandemic outbreak necessitate the development of an anti-influenza vaccine with increased breadth of protection and potential for rapid production and deployment. The hemagglutinin (HA) stem is a promising target for universal influenza vaccine as stem-specific antibodies have the potential to be broadly cross-reactive towards different HA subtypes. Here, we report the design of a bacterially expressed polypeptide that mimics a H5 HA stem by protein minimization to focus the antibody response towards the HA stem. The HA mini-stem folds as a trimer mimicking the HA prefusion conformation. It is resistant to thermal/chemical stress, and it binds to conformation-specific, HA stem-directed broadly neutralizing antibodies with high affinity. Mice vaccinated with the group 1 HA mini-stems are protected from morbidity and mortality against lethal challenge by both group 1 (H5 and H1) and group 2 (H3) influenza viruses, the first report of cross-group protection. Passive transfer of immune serum demonstrates the protection is mediated by stem-specific antibodies. Furthermore, antibodies induced by these HA stems have broad HA reactivity, yet they do not have antibody-dependent enhancement activity.

Determination of the speciation and bioavailability of samarium to Chlamydomonas reinhardtii in the presence of natural organic matter.

PubMed

Rowell, Justine-Anne; Fillion, Marc-Alexandre; Smith, Scott; Wilkinson, Kevin J

2018-06-01

As technological interest and environmental emissions of the rare earth elements increase, it is becoming more important to assess their potential environmental impact. Samarium (Sm) is a lanthanide of intermediate molar mass that is used in numerous high-technology applications including wind turbines, solar panels, and electric vehicles. The present study relates the speciation of Sm determined in the presence of natural organic matter (NOM) to its bioavailability to the unicellular green alga Chlamydomonas reinhardtii. The free ion concentration was determined using a cation exchange resin (ion exchange technique) in dynamic mode and compared with thermodynamic modeling. Short-term biouptake experiments were performed in the presence of 4 types of NOM: Suwannee River fulvic acids, Pahokee Peat fulvic acids, Suwannee River humic acids, and a Luther Marsh dissolved organic matter isolate (90-95% humic acids). It was clearly shown that even a small amount of NOM (0.5 mg C L -1 ) resulted in a significant decrease (10 times) in the Sm internalization fluxes. Furthermore, complexation with humic acids (and the corresponding reduction in Sm bioavailability) was stronger than that with fulvic acids. The results showed that the experimentally measured (free) Sm was a better predictor of Sm internalization than either the total concentrations or the free ion concentrations obtained using thermodynamic modeling. Environ Toxicol Chem 2018;37:1623-1631. © 2018 SETAC. © 2018 SETAC.

[Effect of lignite humic acid on soil ammonia oxidizing archaea community].

PubMed

Dong, Lianhua; Li, Baozhen; Yuan, Hongli; Scow, Kate M

2010-06-01

To illuminate the impact of humic acid (HA) on soil ammonia oxidizing archaea and then reveal the effect of HA on soil nitrogen cycle. Two humic acids (cHA and bHA) were added into the soil amended with urea. Community changes of ammonia oxidizing archaea (AOA) and total archaea were studied with terminal restricted fragment length polymorphism (T-RFLP) and real time PCR in the microcosm experiment. We found that the AOA population size increased significantly and AOA community changed greatly in the urea only treatment. However, HA could inhibit the increase of AOA population, moreover, HA could buffer the change in AOA community showed by canonical correspondence analysis (CCA) result. On the other hand, the total archaeal population decreased significantly in the urea only treatment, but stabilized in the urea with HA treatments, which indicated HA could eliminate the toxicity of urea to total archaea. CCA results showed that incubation time was the most important factor for the total archaeal community, and partial CCA (pCCA, when time as a covariable) result demonstrated that cHA was the most important environmental variable for total archaeal community. These results showed that HA diminished ammonia loss by inhibiting the increase of AOA competing with plant for ammonia, thus HA can increase the urea efficiency.

Preparation, optimization and property of PVA-HA/PAA composite hydrogel.

PubMed

Chen, Kai; Liu, Jinlong; Yang, Xuehui; Zhang, Dekun

2017-09-01

PVA-HA/PAA composite hydrogel is prepared by freezing-thawing, PEG dehydration and annealing method. Orthogonal design method is used to choose the optimization combination. Results showed that HA and PVA have the maximum effect on water content. PVA and freezing-thawing cycles have the maximum effect on creep resistance and stress relaxation rate of hydrogel. Annealing temperature and freezing-thawing cycles have the maximum effect on compressive elastic modulus of hydrogel. Comparing with the water content and mechanical properties of 16 kinds of combination, PVA-HA/PAA composite hydrogel with freezing-thawing cycles of 3, annealing temperature of 120°C, PVA of 16%, HA of 2%, PAA of 4% has the optimization comprehensive properties. PVA-HA/PAA composite hydrogel has a porous network structure. There are some interactions between PVA, HA and PAA in hydrogel and the properties of hydrogel are strengthened. The annealing treatment improves the crystalline and crosslinking of hydrogel. Therefore, the annealing PVA-HA/PAA composite hydrogel has good thermostability, strength and mechanical properties. It also has good lubrication property and its friction coefficient is relative low. Copyright © 2017 Elsevier B.V. All rights reserved.

Humic acids: Structural properties and multiple functionalities for novel technological developments.

PubMed

de Melo, Bruna Alice Gomes; Motta, Fernanda Lopes; Santana, Maria Helena Andrade

2016-05-01

Humic acids (HAs) are macromolecules that comprise humic substances (HS), which are organic matter distributed in terrestrial soil, natural water, and sediment. HAs differ from the other HS fractions (fulvic acid and humins) in that they are soluble in alkaline media, partially soluble in water, and insoluble in acidic media. Due to their amphiphilic character, HAs form micelle-like structures in neutral to acidic conditions, which are useful in agriculture, pollution remediation, medicine and pharmaceuticals. HAs have undefined compositions that vary according to the origin, process of obtainment, and functional groups present in their structures, such as quinones, phenols, and carboxylic acids. Quinones are responsible for the formation of reactive oxygen species (ROS) in HAs, which are useful for wound healing and have fungicidal/bactericidal properties. Phenols and carboxylic acids deprotonate in neutral and alkaline media and are responsible for various other functions, such as the antioxidant and anti-inflammatory properties of HAs. In particular, the presence of phenolic groups in HAs provides antioxidant properties due to their free radical scavenging capacity. This paper describes the main multifunctionalities of HAs associated with their structures and properties, focusing on human health applications, and we note perspectives that may lead to novel technological developments. To the best of our knowledge, this is the first review to address this topic from this approach. Copyright © 2015 Elsevier B.V. All rights reserved.

Clinical comparision of intravesical hyaluronic acid and hyaluronic acid-chondroitin sulphate therapy for patients with bladder pain syndrome/interstitital cystitis.

PubMed

Gülpınar, Omer; Kayış, Aytaç; Süer, Evren; Gökçe, Mehmet İlker; Güçlü, Adil Güçal; Arıkan, Nihat

2014-09-01

Patients with a history of bladder pain syndrome/interstitial cystitis (BPS/IC) and who responded poorly or unsatisfactorily with previous treatment were compared taking intravesical hyaluronic acid (HA) or hyaluronic acid-chondroitin sulphate (HA-CS). Patients were treated with intravesical instillation with 50 mL sterile sodium hyalurinic acid (Hyacyst, Syner-Med, Surrey, UK) (n = 32) and sodium hyaluronate 1.6% sodium chondroitin sulphate 2% (Ialuril, Aspire Pharma, UK) (n = 33). Intravesical instillations were performed weekly in first month, every 15 days in the second month and monthly in third and fourth months, for a total of 8 doses. Patients were evaluated using a visual analog pain scale (VAS), interstitial cystitis symptom index (ICSI), interstitial cystitis problem index (ICPI), voiding diary for frequency/nocturia, cystometric bladder capacity and voided volume at the beginning and at 6 months. All patients had a potassium sensitivity test (PST) initially. Wilcoxon and Mann-Whitney U tests were used for statistical analysis. In total, 53 patients met the study criteria. There were 30 patients in the HA-CS group (mean age: 48.47) and 23 patients in the HA group (mean age: 49.61) (p > 0.05). The initial PST was positive in 71.7% patients (38/53) overall with no difference between groups (p > 0.05). Responses for VAS, ICCS, ICPS, 24-hour frequency/nocturia statistically improved in both groups at 6 months. There was no significant difference in symptomatic improvement (p > 0.05). Eight patients had mild adverse events. HA and HA/CS instillation can be effective in BPS/IC patients who do not respond to conservative treatment. An important limitation of our study is that the HA dosage of the 2 treatment arms were different. It would be more appropriate with same HA dosage in both groups; however, there was no commercially available glycosaminoglycan (GAG) substance with same HA dosage for single and combination therapy. Large, long-term randomized studies

Spectroscopic analyses on sonocatalytic damage to bovine serum albumin (BSA) induced by ZnO/hydroxylapatite (ZnO/HA) composite under ultrasonic irradiation

NASA Astrophysics Data System (ADS)

Wang, Zhiqiu; Li, Ying; Wang, Jun; Zou, Mingming; Gao, Jingqun; Kong, Yumei; Li, Kai; Han, Guangxi

ZnO/hydroxylapatite (ZnO/HA) composite with HA molar content of 6.0% was prepared by the method of precipitation and heat-treated at 500 °C for 40 min and was characterized by powder X-ray diffraction (XRD). The sonocatalytic activities of ZnO/HA composite was carried out through the damage of bovine serum albumin (BSA) in aqueous solution. Furthermore, the effects of several factors on the damage of BSA molecules were evaluated by means of UV-vis and fluorescence spectra. Experimental results indicated that the damage degree of BSA aggravated with the increase of ultrasonic irradiation time, irradiation power and ZnO/HA addition amount, but weakened with the increase of solution acidity and ionic strength. In addition, the damage site to BSA was also studied by synchronous fluorescence technology and the damage site was mainly at tryptophan (Trp) residue. This paper provides a valuable reference for driving sonocatalytic method to treat tumor in clinic application.

Synthesis and characterization of agricultural controllable humic acid superabsorbent.

PubMed

Gao, Lijuan; Wang, Shiqiang; Zhao, Xuefei

2013-12-01

Humic acid superabsorbent polymer (P(AA/AM-HA)) and superabsorbent polymer (P(AA/AM)) were synthesized by aqueous solution polymerization method using acrylic acid (AA), acrylamide (AM) and humic acid (HA) as raw material. The effects of N,N'-methylenebisacrylamide (MBA) crosslinking agent, potassium peroxydisulfate (KPS) initiator, reaction temperature, HA content, ratio of AA to AM, concentration of monomer and neutralization of AA on water absorption were investigated. Absorption and desorption ratios of nitrogen fertilizer and phosphate fertilizer were also investigated by determination of absorption and desorption ratio of NH4(+), PO4(3-) on P(AA/AM-HA) and P(AA/AM). The P(AA/AM-HA) and P(AA/AM) were characterized by Fourier translation infrared spectroscopy, biological photomicroscope and scanning electron microscopy (SEM). The optimal conditions obtained were as follows: the weight ratio of MBA to AA and AM was 0.003; the weight ratio of KPS to AA and AM was 0.008; the weight ratio of HA to AA was 0.1; the mole ratio of AM to AA is 0.1; the mole ratio of NaOH to AA is 0.9; the reaction temperature was 60°C. P(AA/AM-HA) synthesized under optimal conditions, has a good saline tolerance, its water absorbency in distilled water and 0.9 wt.% saline solution is 1180 g/g and 110 g/g, respectively. P(AA/AM-HA) achieves half saturation in 6.5 min. P(AA/AM-HA) is superior to P(AA/AM) on absorption of NH4(+), PO4(3-). The SEM micrograph of P(AA/AM-HA) shows a fine alveolate structure. The biological optical microscope micrograph of P(AA/AM-HA) shows a network structure. Graft polymerization between P(AA/AM) and HA was demonstrated by infrared spectrum. The P(AA/AM-HA) superabsorbent has better absorbing ability of water and fertilizer, electrolytic tolerance and fewer cost than P(AA/AM) superabsorbent. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

[Construction of porous hydroxyapatite (HA) block loaded with cultured chondrocytes].

PubMed

Yan, M; Dang, G

1999-07-01

To construct a kind of bone healing enhancing implant with cultured chondrocytes bound to hydroxyapatite (HA). Chondrocytes were obtained from the costicartilage of rat and were cultured on the porous HA blocks, 3 mm x 3 mm x 4 mm size, for three and seven days. Scanning electron micrograph was taken to show whether the cells grew outside and inside the pore of HA block. The cells cultured on tiny glass sheet for 2 days were used to prove where the cells come from by in situ hybridization technique with alpha1 (II) cDNA probe. Scanning electron micrographs showed that the pores of the HA surface and inside of the blocks are filled with cultured cells, especially the longer cultured block. The cells were chondrocytes confirmed by in situ hybridization. The porous HA can be used as cell cultured substrate and chondrocyte can adhere and proliferate inside the porous HA block.

The Efficacy and Safety of HA IDF Plus (with Lidocaine) Versus HA IDF (Without Lidocaine) in Nasolabial Folds Injection: A Randomized, Multicenter, Double-Blind, Split-Face Study.

PubMed

Lee, Jong-Hun; Kim, Seok-Hwan; Park, Eun-Soo

2017-04-01

Injection-related pain of dermal fillers is a consistent and bothersome problem for patients undergoing soft tissue augmentation. Reducing the pain could improve overall patient satisfaction. The purpose of this study was to compare the pain relief, efficacy, and safety of HA IDF plus containing lidocaine with HA IDF without lidocaine during correction of nasolabial folds (NLFs). Sixty-two subjects were enrolled in a randomized, multicenter, double-blind, split-face study of HA IDF plus and HA IDF for NLF correction. For split-face study, HA IDF plus was injected to one side of NLF, and HA IDF was injected to the other side. The first evaluation variable was the injection site pain measured using a 100-mm visual analogue scale (VAS). The second evaluation variables included the global aesthetic improvement scale, wrinkle severity rating scale, and adverse events. Immediately after injection, 91.94% of subjects experienced at least 10 mm decrease in VAS scores at the side injected with HA IDF plus compared with HA IDF, and the rate of subjects is statistically significant. The two fillers were not significantly different in safety profile or wrinkle correction during the follow-up visit. HA IDF plus significantly reduced the injection-related pain during NLFs correction compared with HA IDF without altering clinical outcomes or safety. Both HA IDF plus and HA IDF were considerably tolerated and most adverse reactions were mild and transient. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Humic Acid-Oxidizing, Nitrate-Reducing Bacteria in Agricultural Soils

PubMed Central

Van Trump, J. Ian; Wrighton, Kelly C.; Thrash, J. Cameron; Weber, Karrie A.; Andersen, Gary L.; Coates, John D.

2011-01-01

ABSTRACT This study demonstrates the prevalence, phylogenetic diversity, and physiology of nitrate-reducing microorganisms capable of utilizing reduced humic acids (HA) as electron donors in agricultural soils. Most probable number (MPN) enumeration of agricultural soils revealed large populations (104 to 106 cells g−1 soil) of microorganisms capable of reducing nitrate while oxidizing the reduced HA analog 2,6-anthrahydroquinone disulfonate (AH2DS) to its corresponding quinone. Nitrate-dependent HA-oxidizing organisms isolated from agricultural soils were phylogenetically diverse and included members of the Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Advective up-flow columns inoculated with corn plot soil and amended with reduced HA and nitrate supported both HA oxidation and enhanced nitrate reduction relative to no-donor or oxidized HA controls. The additional electron donating capacity of reduced HA could reasonably be attributed to the oxidation of reduced functional groups. Subsequent 16S rRNA gene-based high-density oligonucleotide microarray (PhyloChip) indicated that reduced HA columns supported the development of a bacterial community enriched with members of the Acidobacteria, Firmicutes, and Betaproteobacteria relative to the no-donor control and initial inoculum. This study identifies a previously unrecognized role for HA in stimulating denitrification processes in saturated soil systems. Furthermore, this study indicates that reduced humic acids impact soil geochemistry and the indigenous bacterial community composition. PMID:21750120

Fragrance chemicals lyral and lilial decrease viability of HaCat cells' by increasing free radical production and lowering intracellular ATP level: protection by antioxidants.

PubMed

Usta, Julnar; Hachem, Yassmine; El-Rifai, Omar; Bou-Moughlabey, Yolla; Echtay, Karim; Griffiths, David; Nakkash-Chmaisse, Hania; Makki, Rajaa Fakhoury

2013-02-01

We investigate in this study the biochemical effects on cells in culture of two commonly used fragrance chemicals: lyral and lilial. Whereas both chemicals exerted a significant effect on primary keratinocyte(s), HaCat cells, no effect was obtained with any of HepG2, Hek293, Caco2, NIH3T3, and MCF7 cells. Lyral and lilial: (a) decreased the viability of HaCat cells with a 50% cell death at 100 and 60 nM respectively; (b) decreased significantly in a dose dependant manner the intracellular ATP level following 12-h of treatment; (c) inhibited complexes I and II of electron transport chain in liver sub-mitochondrial particles; and (d) increased reactive oxygen species generation that was reversed by N-acetyl cysteine and trolox and the natural antioxidant lipoic acid, without influencing the level of free and/or oxidized glutathione. Lipoic acid protected HaCat cells against the decrease in viability induced by either compound. Dehydrogenation of lyral and lilial produce α,β-unsaturated aldehydes, that reacts with lipoic acid requiring proteins resulting in their inhibition. We propose lyral and lilial as toxic to mitochondria that have a direct effect on electron transport chain, increase ROS production, derange mitochondrial membrane potential, and decrease cellular ATP level, leading thus to cell death. Copyright © 2012 Elsevier Ltd. All rights reserved.

Equilibrium Acidities and Homolytic Bond Dissociation Enthalpies of the Acidic C-H Bonds in P-(Para-substituted benzyl)triphenylphosphonium Cations and Related Cations.

PubMed

Zhang, Xian-Man; Fry, Albert J.; Bordwell, Frederick G.

1996-06-14

Equilibrium acidities (pK(HA)) of six P-(para-substituted benzyl)triphenylphosphonium (p-GC(6)H(4)CH(2)PPh(3)(+)) cations, P-allyltriphenylphosphonium cation, P-cinnamyltriphenylphosphonium cation, and As-(p-cyanobenzyl)triphenylarsonium cation, together with the oxidation potentials [E(ox)(A(-))] of their conjugate anions (ylides) have been measured in dimethyl sulfoxide (DMSO) solution. The acidifying effects of the alpha-triphenylphosphonium groups on the acidic C-H bonds in toluene and propene were found to be ca 25 pK(HA) units (34 kcal/mol). Introduction of an electron-withdrawing group such as 4-NO(2), 4-CN, or 4-Br into the para position of the benzyl ring in p-GC(6)H(4)CH(2)PPh(3)(+) cations resulted in an additional acidity increase, but introduction of the 4-OEt electron-donating group decreases the acidity. The equilibrium acidities of p-GC(6)H(4)CH(2)PPh(3)(+) cations were nicely linearly correlated with the Hammett sigma(-) constants of the substituents (G) with a slope of 4.78 pK(HA) units (R(2) = 0.992) (Figure 1). Reversible oxidation potentials of the P-(para-substituted benzyl)triphenylphosphonium ylides were obtained by fast scan cyclic voltammetry. The homolytic bond dissociation enthalpies (BDEs) of the acidic C-H bonds in these cations, estimated by combining their equilibrium acidities with the oxidation potentials of their corresponding conjugate anions, showed that the alpha-Ph(3)P(+) groups have negligible stabilizing or destabilizing effects on the adjacent radicals. The equilibrium acidity of As-(p-cyanobenzyl)triphenylarsonium cation is 4 pK(HA) units weaker than that of P-(p-cyanobenzyl)triphenylphosphonium cation, but the BDE of the acidic C-H bond in As-(p-cyanobenzyl)triphenylarsonium cation is ca 2 kcal/mol higher than that in P-(p-cyanobenzyl)triphenylphosphonium cation.

Structure and transcription of the Helicoverpa armigera densovirus (HaDV2) genome and its expression strategy in LD652 cells.

PubMed

Xu, Pengjun; Graham, Robert I; Wilson, Kenneth; Wu, Kongming

2017-02-07

Densoviruses (DVs) are highly pathogenic to their hosts. However, we previously reported a mutualistic DV (HaDV2). Very little was known about the characteristics of this virus, so herein we undertook a series of experiments to explore the molecular biology of HaDV2 further. Phylogenetic analysis showed that HaDV2 was similar to members of the genus Iteradensovirus. However, compared to current members of the genus Iteradensovirus, the sequence identity of HaDV2 is less than 44% at the nucleotide-level, and lower than 36, 28 and 19% at the amino-acid-level of VP, NS1 and NS2 proteins, respectively. Moreover, NS1 and NS2 proteins from HaDV2 were smaller than those from other iteradensoviruses due to their shorter N-terminal sequences. Two transcripts of about 2.2 kb coding for the NS proteins and the VP proteins were identified by Northern Blot and RACE analysis. Using specific anti-NS1 and anti-NS2 antibodies, Western Blot analysis revealed a 78 kDa and a 48 kDa protein, respectively. Finally, the localization of both NS1 and NS2 proteins within the cell nucleus was determined by using Green Fluorescent Protein (GFP) labelling. The genome organization, terminal hairpin structure, transcription and expression strategies as well as the mutualistic relationship with its host, suggested that HaDV2 was a novel member of the genus Iteradensovirus within the subfamily Densovirinae.

Surface characterization of colloidal-sol gel derived biphasic HA/FA coatings.

PubMed

Cheng, Kui; Zhang, Sam; Weng, Wenjian

2007-10-01

Hydroxyapatite (HA) powders are ultrasonically dispersed in the precursor of fluoridated hydroxyapatite (FHA) or fluorapatite (FA) to form a "colloidal sol". HA/FA biphasic coatings are prepared on Ti6Al4V substrate via dip coating, 150 degrees C drying and 600 degrees C firing. The coatings show homogenous distribution of HA particles in the FA matrix. The relative phase proportion can be tailored by the amount of HA in the colloidal sol. The surfaces of the coatings consist of two kinds of distinct domains: HA and FA, resulting in a compositionally heterogeneous surface. The biphasic coating surface becomes increasingly rougher with HA powders, from around 200 nm of pure FA to 400-600 nm in Ra of biphasic coatings. The rougher biphasic HA/FA surfaces with chemically controllable domains will favor cell attachment, apatite layer deposition and necessary dissolution in clinical applications.

Speciation and formation of iodinated trihalomethane from microbially derived organic matter during the biological treatment of micro-polluted source water.

PubMed

Wei, Yuanyuan; Liu, Yan; Ma, Luming; Wang, Hongwu; Fan, Jinhong; Liu, Xiang; Dai, Rui-Hua

2013-09-01

Water sources are micro-polluted by the increasing range of anthropogenic activities around them. Disinfection byproduct (DBP) precursors in water have gradually expanded from humic acid (HA) and fulvic acid to other important sources of potential organic matter. This study aimed to provide further insights into the effects of microbially derived organic matter as precursors on iodinated trihalomethane (I-THM) speciation and formation during the biological treatment of micro-polluted source water. The occurrence of I-THMs in drinking water treated by biological processes was investigated. The results showed for the first time that CHCl2I and CHBrClI are emerging DBPs in China. Biological pre-treatment and biological activated carbon can increase levels of microbes, which could serve as DBP precursors. Chlorination experiments with bovine serum albumin (BSA), starch, HA, deoxyribonucleic acid (DNA), and fish oil, confirmed the close correlation between the I-THM species identified during the treatment processes and those predicted from the model compounds. The effects of iodide and bromide on the I-THM speciation and formation were related to the biochemical composition of microbially derived organic precursors. Lipids produced up to 16.98μgL(-1) of CHCl2I at an initial iodide concentration of 2mgL(-1). HA and starch produced less CHCl2I at 3.88 and 3.54μgL(-1), respectively, followed by BSA (1.50μgL(-1)) and DNA (1.35μgL(-1)). Only fish oil produced I-THMs when iodide and bromide were both present in solution; the four other model compounds formed brominated species. Copyright © 2013 Elsevier Ltd. All rights reserved.

Economic co-production of poly(malic acid) and pullulan from Jerusalem artichoke tuber by Aureobasidium pullulans HA-4D.

PubMed

Xia, Jun; Xu, Jiaxing; Liu, Xiaoyan; Xu, Jiming; Wang, Xingfeng; Li, Xiangqian

2017-02-23

poly(L-malic acid) (PMA) is a water-soluble polyester with many attractive properties in medicine and food industries, but the high cost of PMA fermentation has restricted its further application for large-scale production. To overcome this problem, PMA production from Jerusalem artichoke tubers was successfully performed. Additionally, a valuable exopolysaccharide, pullulan, was co-produced with PMA by Aureobasidum pullulans HA-4D. The Jerusalem artichoke medium for PMA and pullulan co-production contained only 100 g/L hydrolysate sugar, 30 g/L CaCO 3 and 1 g/L NaNO 3 . Compared with the glucose medium, the Jerusalem artichoke medium resulted in a higher PMA concentration (114.4 g/L) and a lower pullulan concentration (14.3 g/L) in a 5 L bioreactor. Meanwhile, the activity of pyruvate carboxylase and malate dehydrogenas was significantly increased, while the activity of α-phosphoglucose mutase, UDP-glucose pyrophosphorylase and glucosyltransferase was not affected. To assay the economic-feasibility, large-scale production in a 1 t fermentor was performed, yielding 117.5 g/L PMA and 15.2 g/L pullulan. In this study, an economical co-production system for PMA and pullulan from Jerusalem artichoke was developed. The medium for PMA and pullulan co-production was significantly simplified when Jerusalem artichoke tubers were used. With the simplified medium, PMA production was obviously stimulated, which would be associated with the improved activity of pyruvate carboxylase and malate dehydrogenas.

Compost and Crude Humic Substances Produced from Selected Wastes and Their Effects on Zea mays L. Nutrient Uptake and Growth

PubMed Central

Palanivell, Perumal; Susilawati, Kasim; Ahmed, Osumanu Haruna; Majid, Nik Muhamad

2013-01-01

Production of agriculture and timber commodities leads generation of enormous quantity of wastes. Improper disposal of these agroindustrial wastes pollutes the environment. This problem could be reduced by adding value to them. Therefore, a study was carried out to analyse and compare the nutrients content of RS, RH, SD, and EFB of composts and crude humic substances; furthermore, their effect on growth, dry matter production, and nutrient uptake for Zea mays L., and selected soil chemical properties were evaluated. Standard procedures were used to analyze humic acids (HA), crude fulvic acids (CFA), crude humin (CH), soil, dry matter production and nutrient uptake. Sawdust and RS compost matured at 42 and 47 days, respectively, while RH and EFB composts were less matured at 49th day of composting. Rice straw compost had higher ash, N, P, CEC, HA, K, and Fe contents with lower organic matter, total organic carbon, and C/N and C/P ratios. The HA of sawdust compost showed higher carbon, carboxylic, K, and Ca contents compared to those of RS, RH, and EFB. Crude FA of RS compost showed highest pH, total K, Ca, Mg, and Na contents. Crude humin from RS compost had higher contents of ash, N, P, and CEC. Rice straw was superior in compost, CFA, and CH, while sawdust compost was superior in HA. Application of sawdust compost significantly increased maize plants' diameter, height, dry matter production, N, P, and cations uptake. It also reduced N, P, and K based chemical fertilizer use by 90%. Application of CH and the composts evaluated in this study could be used as an alternative for chemical fertilizers in maize cultivation. PMID:24319353

Effect of humic substances on P sorption capacity of three different soils

NASA Astrophysics Data System (ADS)

Delgado, Antonio

2010-05-01

Organic matter decreases P sorption by soils. It has been demonstrated the effect of low molecular weight compounds decreasing P adsorption on active surfaces and the effect of humic and fulvic acids inhibiting the precipitation of hydroxyapatite and favouring the formation of more soluble phosphates. This contributes to increase the recovery of applied P fertilizer. The objective of this work was to study the effect of 4 different humic substances (commercially available and provided by Tradecorp Internacional S.A.) on the sorption capacity of three soils differing widely in chemical properties (two calcareous from south Spain, pH 8 and 8.5, and other acidic from Brazil, pH 5.9 and 50 % of exchangeable basic cations). To this end, sorption isotherms were performed at a soil:0.01 M CaCl2 ratio of 1:10 at 6, 30 and 90 days. 2.5 mg of humic substances per g of soil were added to the solution. Data were fitted to the best model and linearized sorption curves for each humic substance were compared with the linearized sorption curve for the control without humic substances application (intersection point and slopes). Soil from Brazil showed a much higher sorption capacity (400 mg P kg-1 soil sorbed at 1 mg L-1 of P in the solution at 1 day) than the other two soils (50 and 100 mg P kg-1). Slow reactions significantly contributed to P sorption in the three soils, amounts sorbed at 90 days being twice than those sorbed at 1 day. Two of the products increased P sorption in the soil from Brazil at 1 day. At 90 days all the products increased P sorption significantly. This increased P sorption can be only explained by metal complexation by the substances applied, which may result in organo-metallic compounds with a high P sorption capacity. This effect was independent of the proportion of humic and fulvic acids in the applied products because the amounts of metal complexed by these compouds depend on the amount of functional groups to coordinate with metals. In the Spanish

Influence of D-Penicillamine on the Viscosity of Hyaluronic Acid Solutions

NASA Astrophysics Data System (ADS)

Liang, Jing; Krause, Wendy E.; Colby, Ralph H.

2006-03-01

Polyelectrolyte hyaluronic acid (HA, hyaluronan) is an important component in synovial fluid. Its presence results in highly viscoelastic solutions with excellent lubricating and shock-absorbing properties. In comparison to healthy synovial fluid, diseased fluid has a reduced viscosity. In osteoarthritis this reduction in viscosity results from a decline in both the molecular weight and concentration of hyaluronic acid HA. Initial results indicate that D-penicillamine affects the rheology of bovine synovial fluid, a model synovial fluid solution, and its components, including HA. In order to understand how D-penicillamine modifies the viscosity of these solutions, the rheological properties of sodium hyaluronate (NaHA) in phosphate-buffered saline (PBS) with D-penicillamine were studied as function of time, D-penicillamine concentration (0 -- 0.01 M), and storage conditions. Penicillamine has a complex, time dependent effect on the viscosity of NaHA solutions---reducing the zero shear rate viscosity of a 3 mg/mL NaHA in PBS by ca. 40% after 44 days.

Precision Landing and Hazard Avoidance (PL&HA) Domain

NASA Technical Reports Server (NTRS)

Robertson, Edward A.; Carson, John M., III

2016-01-01

The Precision Landing and Hazard Avoidance (PL&HA) domain addresses the development, integration, testing, and spaceflight infusion of sensing, processing, and GN&C (Guidance, Navigation and Control) functions critical to the success and safety of future human and robotic exploration missions. PL&HA sensors also have applications to other mission events, such as rendezvous and docking.

CoralWatch Data Analysis at Hoi Ha Wan Marine Park, Hong Kong

NASA Astrophysics Data System (ADS)

Lau, A.; Hodgson, P.

2015-12-01

CoralWatch is a conservation organization that is based at the University of Queensland in Australia. Their development of the "Coral Health Chart" standardized the colour of corals for the further investigation of coral health and bleaching. The location of this project is in the NE part of Hong Kong in New Territories. The location faces ShenZhen, a heavily industrialized city, which is known for its pollution of the Pearl River. This area is protected by the Hong Kong Government and the WWF since 1996.Human activities have caused large amounts of greenhouse gasses to be released into the atmosphere. Carbon dioxide has caused the global temperature to rise and made ocean waters more acidic due to ocean respiration. The ocean is a carbon sink for mankind and the effect of severe acidification is negatively affecting marine life. The increase of temperature diminishes the amount of diversity of marine life; the decreasing acidity of the water has eliminated many species of shellfish and sea anemone; the increase of marine exploitation has decreased the diversity of marine life. The release of toxic waste, mainly mercury, waste and plastic products has also polluted the oceans which negatively impact coral reefs and endanger marine life.The data has been collected by observing the colours and discolouration (bleaching) of the corals of approximately 40 colonies per month. The species of coral in Hoi Ha Wan include, Favites flexuosa, Goniopora columna,Leptastrea purpurea, Lithophyllon undulatum, Pavona decussata. and Platygyra acuta (AFCD,1). The evaluation of four years of coralwatch data has shown the bleaching of hard boulder corals in Hoi Ha Wan, Hong Kong, has halted and the reefs are being to show signs of regeneration. Local marine biologists credited the improved situation of the corals to protected status of the area.

Promotion of PDT efficacy by HA14-1

NASA Astrophysics Data System (ADS)

Kessel, David; Price, Michael; Haagenson, Kelly

2008-02-01

Photodynamic therapy (PDT) can target the members of the Bcl-2 family that protect cells from the initiation of apoptosis, a well-known death pathway. We examined the ability of HA14-1, a non-peptidic Bcl-2/Bcl-xL antagonist, to promote the efficacy of PDT. The photosensitizer was the porphycene CPO that causes photodamage to Bcl-2 located in the endoplasmic reticulum. Using low PDT doses together with LD5-20 concentrations of HA14-1, we found a marked synergistic effect. These results indicate that such an effect occurs when PDT is coupled with pharmacologic suppression of Bcl-2 function. HA14-1 is an unstable compound that decomposes in aqueous solution. This resulted in a rapid (~60 sec) burst of fluorescence that closely mimicked the properties of many fluorescent probes, but was traced to an effect produced when HA14-1 contacts serum proteins. Other Bcl-2 antagonists that do not produce any intrinsic fluorescence also promoted PDT efficacy. Moreover, briefly storing HA14-1 in aqueous medium until the fluorescent burst is over does not inhibit a subsequent synergistic promotion of PDT efficacy. We conclude that Bcl-2 antagonists can promote the efficacy of low-dose PDT in a manner unrelated to ROS production. The most likely explanation is an enhanced loss of anti-apoptotic Bcl-2 family function such that a threshold for initiation of apoptosis is crossed.