A glimpse into the genetic basis of symbiosis between Hydrogenophaga and their helper strains in the biodegradation of 4-aminobenzenesulfonate

PubMed Central

Kim, Kangsan; Gan, Han Ming

2017-01-01

We report the whole genome sequences of Hydrogenophaga intermedia S1 and Agrobacterium radiobacter S2, the first reported bacterial co-culture capable of degrading 4-aminobenzenesulfonate (4-ABS), a recalcitrant industrial waste product. To gain insights into the genetic basis for the syntrophic interaction between this symbiotic pair and also another recently reported Hydrogenophaga associated co-culture, Hydrogenophaga sp. PBC and Ralstonia sp. PBA, we performed detailed genetic analysis of these four strains focusing on the metabolic pathways associated with biotin, para-aminobenzoic acid (pABA), and protocatechuate metabolism. Both assembled Hydrogenophaga draft genomes are missing a majority of the genetic components associated in the biosynthetic pathway of pABA and biotin. Interestingly, a fused pABA synthase was found in R. sp PBA but not in A. radiobacter S2. Furthermore, using whole genome data, the taxonomic classification of R. sp. PBA and A. radiobacter S2 (both previously inferred from 16S rRNA gene) was re-investigated, providing new evidence to propose for their re-classification at the genus and species level, respectively PMID:28775791

The influence of solution environment on the nucleation kinetics and crystallisability of para-aminobenzoic acid.

PubMed

Turner, T D; Corzo, D M C; Toroz, D; Curtis, A; Dos Santos, M M; Hammond, R B; Lai, X; Roberts, K J

2016-10-05

The influence of solvent type on the solution thermodynamics, nucleation-kinetics and crystal growth of alpha para-aminobenzoic acid (PABA) crystallising from supersaturated ethanol, acetonitrile and water solutions, is examined using poly-thermal analysis of the metastable zone width. Application of a recently proposed model for analysis of crystallisation kinetics (J. Cryst. Growth, 2010, 312, 698-704) indicates a solvent and concentration dependence of the nucleation mechanism and key nucleation parameters for the alpha form of PABA. The mechanism of nucleation is found to change from instantaneous to progressive with decreasing concentration and also when changing the solvent from ethanol to acetonitrile to water. The dependence of the nucleation mechanism is correlated to the kinetic component of the nucleation rate through calculated values of instantaneously nucleated crystallites, which increase from 1.40 × 10 9 m -3 in ethanol to 1.08 × 10 10 m -3 in acetonitrile to 2.58 × 10 10 m -3 in water. This in combination with low calculated number concentrations of interfacial tension between 1.13 and 2.71 mJ m -2 , supports the conclusion that the kinetic component of the nucleation rate is more limiting when crystallising PABA from ethanol solutions in comparison to water solutions. This finding is further supported by molecular dynamics simulations of the solvation free energy of PABA, which is found to be greatest in water, -42.4 kJ mol -1 and lowest in ethanol, -58.5 kJ mol -1 .

Evolution of glutamine amidotransferase genes. Nucleotide sequences of the pabA genes from Salmonella typhimurium, Klebsiella aerogenes and Serratia marcescens.

PubMed

Kaplan, J B; Merkel, W K; Nichols, B P

1985-06-05

The amide group of glutamine is a source of nitrogen in the biosynthesis of a variety of compounds. These reactions are catalyzed by a group of enzymes known as glutamine amidotransferases; two of these, the glutamine amidotransferase subunits of p-aminobenzoate synthase and anthranilate synthase have been studied in detail and have been shown to be structurally and functionally related. In some micro-organisms, p-aminobenzoate synthase and anthranilate synthase share a common glutamine amidotransferase subunit. We report here the primary DNA and deduced amino acid sequences of the p-aminobenzoate synthase glutamine amidotransferase subunits from Salmonella typhimurium, Klebsiella aerogenes and Serratia marcescens. A comparison of these glutamine amidotransferase sequences to the sequences of ten others, including some that function specifically in either the p-aminobenzoate synthase or anthranilate synthase complexes and some that are shared by both synthase complexes, has revealed several interesting features of the structure and organization of these genes, and has allowed us to speculate as to the evolutionary history of this family of enzymes. We propose a model for the evolution of the p-aminobenzoate synthase and anthranilate synthase glutamine amidotransferase subunits in which the duplication and subsequent divergence of the genetic information encoding a shared glutamine amidotransferase subunit led to the evolution of two new pathway-specific enzymes.

UVA-potentiated damage to calf thymus DNA by Fenton reaction system and protection by para-aminobenzoic acid.

PubMed

Shih, M K; Hu, M L

1996-03-01

Calf thymus DNA was irradiated with low-intensity UVA (main output at 365 nm, 2 mW cm-2 or 36 kJ m-2 for 30 min), and the role of metal ions, hydrogen peroxide and reactive oxygen species (ROS) was examined. DNA damage was measured as thiobarbituric acid-reactive substances (possibly from degradation of deoxyribose) and as changes in ethidium bromide-DNA fluorescence due to unwinding from strand breaks. Under the present experimental conditions, UVA alone or in the presence of H2O2 had no effect on DNA but slightly enhanced the damage by iron/EDTA. Ultraviolet A strongly enhanced DNA damage (ca four- to five-fold) by the Fenton reaction system (50 microM Fe2+/100 microM EDTA + 0.5 mM H2O2). The results suggest that the Fenton reaction system was "photosensitized" to damage DNA by low-intensity UVA radiation. The enhanced damage by UVA was attributed in part to the reduction of Fe3+ to Fe2+. Ultraviolet A had no effect when iron (ferric or ferrous) ions were replaced by Cu2+, Zn2+, Mn2+ or Cd2+. The ROS involved in the UVA-enhanced damage to DNA by the Fenton reagents were OH and, to a lesser extent, superoxide anions. The UVA-potentiated DNA damage by the Fenton reaction system was then used to examine the protective effect of para-aminobenzoate (PABA), a UVB-absorbing sunscreen that protects against photocarcinogenesis in hairless mice. The results show that PABA and mannitol dose-dependently inhibited the damage with concentrations required for 50% inhibition at 0.1 mM and 3 mM, respectively. The protection by PABA was attributed to its radical-scavenging ability because PABA does not absorb light in the UVA region. These findings may be relevant to the biological damage by UVA and suggest that PABA is useful in protection against photocarcinogenesis by wide-range UV radiation.

Combinations of 4-aminobenzoic acid competitors and dihydrofolate dehydrogenase inhibitors in the chemotherapy of malaria

PubMed Central

Laing, A. B. G.

1974-01-01

Potentiating combinations of 4-aminobenzoic acid (PABA) competitors, such as sulfadoxine, sulfalene, or dapsone, and dihydrofolate dehydrogenasea (1.5.1.4) inhibitors, such as pyrimethamine or proguanil, have been subjected to various trials over the last decade. By and large they have proved to be effective agents against drug-resistant strains of malaria parasites, and with the small doses required they have been free of toxic effects. Parasite resistance to such combinations has seldom occurred but may be associated with cross-resistance to other combinations. These combinations should be reserved for the treatment of chloroquine-resistant infections and for use as adjuvants in organized malaria eradication campaigns. PMID:4613505

The effects of dissolved organic matter and feeding on bioconcentration and oxidative stress of ethylhexyl dimethyl p-aminobenzoate (OD-PABA) to crucian carp (Carassius auratus).

PubMed

Ma, Binni; Lu, Guanghua; Yang, Haohan; Liu, Jianchao; Yan, Zhenhua; Nkoom, Matthew

2018-03-01

Bioconcentration of UV filters in organisms is an important indicator for the assessment of environmental hazards. However, bioconcentration testing rarely accounts for the influence of natural aquatic environmental factors. In order to better assess the ecological risk of organic UV filters (OUV-Fs) in an actual water environment, this study determined the influences of dissolved organic matter (DOM) (0, 1, 10, and 20 mg/L) and feeding (0, 0.5, 1, and 2% body weight/d) on bioconcentration of ethylhexyl dimethyl p-aminobenzoate (OD-PABA) in various tissues of crucian carp (Carassius auratus). Moreover, oxidative stress in the fish liver caused by the OD-PABA was also investigated by measuring activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST), and levels of glutathione (GSH) and malondialdehyde (MDA). The bioconcentration of OD-PABA in the fish tissues was significantly decreased with the presence of DOM indicating a reduction of OD-PABA bioavailability caused by DOM. The bioconcentration factors (BCFs) decreased by 28.00~50.93% in the muscle, 72.67~96.74% in the gill, 37.84~87.72% in the liver, and 10.32~79.38% in the kidney at different DOM concentrations compared to those of the non-DOM treatments. Significant changes in SOD, CAT, GST, GSH, and MDA levels were found in the DOM- and OD-PABA-alone treatments. However, there were no significant differences in the SOD, CAT, GST, and MDA levels found when co-exposure to OD-PABA and DOM. Feeding led to lower OD-PABA concentrations in the fish tissues, and the concentrations were decreased with increasing feeding ratios. BCFs in various tissues reduced by 39.75~72.52% in the muscle, 56.86~79.73% in the gill, 66.41~87.50% in the liver, and 75.88~89.10% in the kidney, respectively. In the unfed treatments, the levels of SOD and MDA were significantly higher than those of the fed ones while GST and GSH levels were remarkably inhibited indicating the enhanced effect of starvation to oxidative stress. There was no markedly alternation of the biomarker levels observed between different fed treatments. In conclusion, our study indicated that both DOM and feeding reduced bioconcentration of OD-PABA and alleviated oxidative stress to some extent in the crucian carp.

Vitamin Requirements of Several Cellulolytic Rumen Bacteria1

PubMed Central

Scott, H. W.; Dehority, B. A.

1965-01-01

Scott, H. W. (Ohio Agricultural Experiment Station, Wooster), and B. A. Dehority. Vitamin requirements of several cellulolytic rumen bacteria. J. Bacteriol. 89:1169–1175. 1965.—Four strains of cellulolytic bacteria recently isolated from in vitro rumen fermentations were used in this study. Nine water-soluble vitamins were tested in single-deletion and single-addition plus biotin experiments, each with and without charcoal-extracted casein hydrolysate. Bacteroides succinogenes A3C and B21a required only biotin under the above experimental conditions. Ruminococcus flavefaciens B34b showed an absolute requirement for biotin and was stimulated by p-aminobenzoic acid (PABA) in the single-deletion experiments. In the single-addition plus biotin experiments, PABA and, to a lesser extent, vitamin B12 appeared to be required for maximal growth. The presence or absence of casein hydrolysate did not affect the vitamin requirements for the aforementioned three strains. In the single-deletion experiments, R. flavefaciens Cla showed an absolute requirement for biotin and, when casein hydrolysate was omitted, for B12. When casein hydrolysate was present, no requirement for B12 could be observed. In the single-addition experiments where the basal medium contained biotin and casein hydrolysate or B12, PABA was required for maximal growth; however, the single deletion of PABA caused only slight retardation of growth. Investigation of the B12 or casein hydrolysate requirement of Cla revealed that a mixture of purified amino acids simulating casein hydrolysate satisfied this requirement. Subsequent work indicated that this requirement could be satisfied by the amino acid methionine. PMID:14292981

Aminobenzoates as building blocks for natural product assembly lines.

PubMed

Walsh, Christopher T; Haynes, Stuart W; Ames, Brian D

2012-01-01

The ortho-, meta-, and para- regioisomers of aminobenzoate are building blocks for a wide range of microbial natural products. Both the ortho-isomer (anthranilate) and PABA derive from the central shikimate pathway metabolite chorismate while the meta-isomer is not available by that route and starts from UDP-3-aminoglucose. PABA is largely funnelled into folate biosynthesis while anthranilate is the scaffold for biosynthetic elaboration into many natural heterocycles, most notably with its role in indole formation for tryptophan biosynthesis. Anthranilate is also converted to benzodiazepinones, fumiquinazolines, quinoxalines, phenoxazines, benzoxazolinates, quinolones, and phenazines, often with redox enzyme participation. The 5-hydroxy form of 3-aminobenzaote is the starter unit for ansa-bridged rifamycins, ansamitocins, and geldanamycins, whereas regioisomers 2-hydroxy, 4-hydroxy and 2,4-dihydroxy-3-aminobenzoate are key components of antimycin, grixazone, and platencin and platensimycin biosynthesis, respectively. The enzymatic mechanisms for generation of the aminobenzoate regioisomers and their subsequent utilization for diverse heterocycle and macrocycle construction are examined.

Coq6 Is Responsible for the C4-deamination Reaction in Coenzyme Q Biosynthesis in Saccharomyces cerevisiae*

PubMed Central

Ozeir, Mohammad; Pelosi, Ludovic; Ismail, Alexandre; Mellot-Draznieks, Caroline; Fontecave, Marc; Pierrel, Fabien

2015-01-01

The yeast Saccharomyces cerevisiae is able to use para-aminobenzoic acid (pABA) in addition to 4-hydroxybenzoic acid as a precursor of coenzyme Q, a redox lipid essential to the function of the mitochondrial respiratory chain. The biosynthesis of coenzyme Q from pABA requires a deamination reaction at position C4 of the benzene ring to substitute the amino group with an hydroxyl group. We show here that the FAD-dependent monooxygenase Coq6, which is known to hydroxylate position C5, also deaminates position C4 in a reaction implicating molecular oxygen, as demonstrated with labeling experiments. We identify mutations in Coq6 that abrogate the C4-deamination activity, whereas preserving the C5-hydroxylation activity. Several results support that the deletion of Coq9 impacts Coq6, thus explaining the C4-deamination defect observed in Δcoq9 cells. The vast majority of flavin monooxygenases catalyze hydroxylation reactions on a single position of their substrate. Coq6 is thus a rare example of a flavin monooxygenase that is able to act on two different carbon atoms of its C4-aminated substrate, allowing its deamination and ultimately its conversion into coenzyme Q by the other proteins constituting the coenzyme Q biosynthetic pathway. PMID:26260787

Contact urticaria, allergic contact dermatitis, and photoallergic contact dermatitis from oxybenzone.

PubMed

Landers, Maeran; Law, Sandra; Storrs, Frances J

2003-03-01

There is little literature regarding conventional patch tests and photopatch tests to oxybenzone resulting in both immediate- and delayed-type hypersensitivity reactions. A patient was patch-tested and photopatch-tested to various sunscreen chemicals. Both immediate- and delayed-type hypersensitivity reactions were observed with oxybenzone. The positive patch tests were also photoaccentuated. Oxybenzone, a common sunscreen allergen, can result in both contact urticaria and delayed-type hypersensitivity on both conventional patch testing and photopatch testing. Allergic contact dermatitis to sunscreen chemicals has traditionally included contact urticaria, allergic contact dermatitis, and photoallergic contact dermatitis. Due to the recognition of p-aminobenzoic acid (PABA) and its esters as sensitizers, the presence of benzophenones in "PABA-free" sunscreens has become more prevalent, especially in sunscreens with a sun protection factor (SPF) greater than 8. In our patient, immediate- and delayed-type hypersensitivity reactions were seen to oxybenzone (2-hydroxy-4-methoxybenzophenone, 2-benzoyl-5-methoxyphenol, benzophenone-3, Eusolex 4360, Escalol 567, EUSORB 228, Spectra-Sorb UV-9, Uvinul M-40) upon conventional patch testing and photopatch testing.

Effects of pig slurry on the sorption of sulfonamide antibiotics in soil.

PubMed

Thiele-Bruhn, S; Aust, M O

2004-07-01

Sorption of p-aminobenzoic acid (pABA) and five sulfonamide antibiotics to loess Chernozem topsoil amended with varied additions of pig slurry was investigated in batch trials. In unfertilized soil, partition coefficients (Kd) of sulfonamides ranged from 0.3 to 2.0. Strong sorption nonlinearity (1/n = 0.5 to 0.8) was best fitted by the Freundlich isotherm (R2 = 0.7 to 1.0) and was indicative for specific sorption mechanisms. Adsorption to pig slurry was much stronger, and nondesorbable portions were increased compared with soil. However, in a mixture of soil and slurry (50:1 w/w), sorption of the antibiotics was significantly decreased at a lower concentration range of pABA and the sulfonamides. This was attributed to competitive adsorption of dissolved organic matter (DOM) constituents from manure. An increase in pig slurry amendment resulted in increased total organic matter, DOM concentration, and ionic strength, but pH decreased. As a result, the nonadsorbed portions of pABA, sulfanilamide, and sulfadiazine (logD(ow) < -0.4) ranged from 47% to 82% of the applied concentration in the differently manured substrates. Dissolved fractions of the antibiotics reached a maximum at a soil-slurry ratio of 9:1 and decreased with further addition of manure. This decrease was related to the formation of less-effective DOM associates in solution. The adsorbed and desorbed portions of the less-polar substances--sulfadimidine, sulfadimethoxine, and sulfapyridine (logD(ow) > 0.1)--remained nearly constant in the presence of increased manure input. The pH changes caused by manure amendment strongly affected ionisation status of the latter compounds, thus resulting in increased adsorption, which compensated the mobilizing effect of DOM. It is suggested that the effect of manure be considered in test methods to determine the soil retention of pharmaceutical substances.

Cocrystals of Hydrochlorothiazide: Solubility and Diffusion/Permeability Enhancements through Drug-Coformer Interactions.

PubMed

Sanphui, Palash; Devi, V Kusum; Clara, Deepa; Malviya, Nidhi; Ganguly, Somnath; Desiraju, Gautam R

2015-05-04

Hydrochlorothiazide (HCT) is a diuretic and a BCS class IV drug with low solubility and low permeability, exhibiting poor oral absorption. The present study attempts to improve the physicochemical properties of the drug using a crystal engineering approach with cocrystals. Such multicomponent crystals of HCT with nicotinic acid (NIC), nicotinamide (NCT), 4-aminobenzoic acid (PABA), succinamide (SAM), and resorcinol (RES) were prepared using liquid-assisted grinding, and their solubilities in pH 7.4 buffer were evaluated. Diffusion and membrane permeability were studied using a Franz diffusion cell. Except for the SAM and NIC cocrystals, all other binary systems exhibited improved solubility. All of the cocrystals showed improved diffusion/membrane permeability compared to that of HCT with the exception of the SAM cocrystal. When the solubility was high, as in the case of PABA, NCT, and RES cocrystals, the flux/permeability dropped slightly. This is in agreement with the expected interplay between solubility and permeability. Improved solubility/permeability is attributed to new drug-coformer interactions. Cocrystals of SAM, however, showed poor solubility and flux. This cocrystal contains a primary sulfonamide dimer synthon similar to that of HCT polymorphs, which may be a reason for its unusual behavior. Hirshfeld surface analysis was carried out in all cases to determine whether a correlation exists between cocrystal permeability and drug-coformer interactions.

4-N-pyridin-2-yl-benzamide nanotubes compatible with mouse stem cell and oral delivery in Drosophila

NASA Astrophysics Data System (ADS)

Yadav, Jhillu S.; Lavanya, Madugula P.; Das, Pragna P.; Bag, Indira; Krishnan, Anita; Jagannadh, Bulusu; Mohapatra, Debendra K.; Pal Bhadra, Manika; Bhadra, Utpal

2010-04-01

p-aminobenzoic acid (PABA), a structural moiety of many commercial drugs, is self-assembled with linker alkyl side chains to form tubular nanostructures. The tubes exhibited fluorescence either intrinsic or from fluorescent molecules embedded in the wall during self-assembly. Uptake and inter-cellular delivery of the conjugated nanotubes in human cancer cells and in mouse embryonic stem cells were demonstrated by fluorescence imaging and flow cytometry. Biocompatibility, cytotoxicity and clearance were monitored both ex vivo in mouse multipotent embryonic stem cells and in vivo in adult Drosophila. Accumulation of nanotubes had no adverse effects and abnormalities on stem cell morphology and proliferation rate. A distinct distribution of two separate nanotubes in various internal organs of Drosophila interprets that accumulation of nanomaterials might be interdependent on the side chain modifications and physiological settings of cell or tissue types. Unlike carbon nanomaterials, exposure of PABA nanotubes does not produce any hazards including locomotion defects and mortality of adult flies. Despite differential uptake and clearance from multiple live tissues, the use of self-assembled nanotubes can add new dimensions and scope to the development of dual-purpose oral carriers for the fulfilment of many biological promises.

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.

PubMed

Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

2014-03-01

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM-INA cocrystal and a binary adduct ACM-PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM-PAM and ACM-CPR, and the piperazine salt ACM-PPZ were solved from high-resolution powder X-ray diffraction data. The ACM-INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N-H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM-PAM cocrystal, while ACM-CPR contains carboxamide dimers of caprolactam along with acid-carbonyl (ACM) hydrogen bonds. The cocrystals ACM-INA, ACM-PAM and ACM-CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM-PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM-PPZ salt and ACM-nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM-PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug.

Free fatty acids chain length distribution affects the permeability of skin lipid model membranes.

PubMed

Uchiyama, Masayuki; Oguri, Masashi; Mojumdar, Enamul H; Gooris, Gert S; Bouwstra, Joke A

2016-09-01

The lipid matrix in the stratum corneum (SC) plays an important role in the barrier function of the skin. The main lipid classes in this lipid matrix are ceramides (CERs), cholesterol (CHOL) and free fatty acids (FFAs). The aim of this study was to determine whether a variation in CER subclass composition and chain length distribution of FFAs affect the permeability of this matrix. To examine this, we make use of lipid model membranes, referred to as stratum corneum substitute (SCS). We prepared SCS containing i) single CER subclass with either a single FFA or a mixture of FFAs and CHOL, or ii) a mixture of various CER subclasses with either a single FFA or a mixture of FFAs and CHOL. In vitro permeation studies were performed using ethyl-p-aminobenzoic acid (E-PABA) as a model drug. The flux of E-PABA across the SCS containing the mixture of FFAs was higher than that across the SCS containing a single FA with a chain length of 24 C atoms (FA C24), while the E-PABA flux was not effected by the CER composition. To select the underlying factors for the changes in permeability, the SCSs were examined by Fourier transform infrared spectroscopy (FTIR) and Small angle X-ray scattering (SAXS). All lipid models demonstrated a similar phase behavior. However, when focusing on the conformational ordering of the individual FFA chains, the shorter chain FFA (with a chain length of 16, 18 or 20 C atoms forming only 11m/m% of the total FFA level) had a higher conformational disordering, while the conformational ordering of the chains of the CER and FA C24 and FA C22 hardly did not change irrespective of the composition of the SCS. In conclusion, the conformational mobility of the short chain FFAs present only at low levels in the model SC lipid membranes has a great impact on the permeability of E-PABA. Copyright © 2016 Elsevier B.V. All rights reserved.

Human neuronal coenzyme Q10 deficiency results in global loss of mitochondrial respiratory chain activity, increased mitochondrial oxidative stress and reversal of ATP synthase activity: implications for pathogenesis and treatment.

PubMed

Duberley, Kate E C; Abramov, Andrey Y; Chalasani, Annapurna; Heales, Simon J; Rahman, Shamima; Hargreaves, Iain P

2013-01-01

Disorders of coenzyme Q(10) (CoQ(10)) biosynthesis represent the most treatable subgroup of mitochondrial diseases. Neurological involvement is frequently observed in CoQ(10) deficiency, typically presenting as cerebellar ataxia and/or seizures. The aetiology of the neurological presentation of CoQ(10) deficiency has yet to be fully elucidated and therefore in order to investigate these phenomena we have established a neuronal cell model of CoQ(10) deficiency by treatment of neuronal SH-SY5Y cell line with para-aminobenzoic acid (PABA). PABA is a competitive inhibitor of the CoQ(10) biosynthetic pathway enzyme, COQ2. PABA treatment (1 mM) resulted in a 54 % decrease (46 % residual CoQ(10)) decrease in neuronal CoQ(10) status (p < 0.01). Reduction of neuronal CoQ(10) status was accompanied by a progressive decrease in mitochondrial respiratory chain enzyme activities, with a 67.5 % decrease in cellular ATP production at 46 % residual CoQ(10). Mitochondrial oxidative stress increased four-fold at 77 % and 46 % residual CoQ(10). A 40 % increase in mitochondrial membrane potential was detected at 46 % residual CoQ(10) with depolarisation following oligomycin treatment suggesting a reversal of complex V activity. This neuronal cell model provides insights into the effects of CoQ(10) deficiency on neuronal mitochondrial function and oxidative stress, and will be an important tool to evaluate candidate therapies for neurological conditions associated with CoQ(10) deficiency.

Sulfamethazine Suppresses Epigenetic Silencing in Arabidopsis by Impairing Folate Synthesis[W

PubMed Central

Zhang, Huiming; Deng, Xiangyang; Miki, Daisuke; Cutler, Sean; La, Honggui; Hou, Yueh-Ju; Oh, JeeEun; Zhu, Jian-Kang

2012-01-01

DNA methylation is a critical, dynamically regulated epigenetic mark. Small chemicals can be valuable tools in probing cellular processes, but the set of chemicals with broad effects on epigenetic regulation is very limited. Using the Arabidopsis thaliana repressor of silencing1 mutant, in which transgenes are transcriptionally silenced, we performed chemical genetic screens and found sulfamethazine (SMZ) as a chemical suppressor of epigenetic silencing. SMZ treatment released the silencing of transgenes as well as endogenous transposons and other repetitive elements. Plants treated with SMZ exhibit substantially reduced levels of DNA methylation and histone H3 Lys-9 dimethylation, but heterochromatic siRNA levels were not affected. SMZ is a structural analog and competitive antagonist to p-aminobenzoic acid (PABA), which is a precursor of folates. SMZ decreased the plant folate pool size and caused methyl deficiency, as demonstrated by reductions in S-adenosylmethionine levels and in global DNA methylation. Exogenous application of PABA or compounds downstream in the folate biosynthesis pathway restored transcriptional silencing in SMZ-treated plants. Together, our results revealed a novel type of chemical suppressor of epigenetic silencing, which may serve as a valuable tool for studying the roles and mechanisms of epigenetic regulation and underscores an important linkage between primary metabolism and epigenetic gene regulation. PMID:22447685

The pH-dependent local anesthetic activity of diethylaminoethanol, a procaine metabolite.

PubMed

Butterworth, J F; Lief, P A; Strichartz, G R

1988-04-01

To test whether the products of procaine hydrolysis have local anesthetic actions resembling those of procaine, the authors compared the ability of procaine and its metabolites diethylaminoethanol (DEAE) and para-aminobenzoic acid (PABA) to block compound action potentials in excised, desheathed frog and rat sciatic nerves. Studies were performed in solutions of impermeant buffers at pH 7.4 (corresponding to mammalian physiologic pH) and at pH 9.2 (close to the pKa of procaine and DEAE) to test for extracellular pH-dependent increases in drug permeation and potency. Both procaine and DEAE inhibited compound action potentials at pH 7.4 and 9.2 in a reversible and dose-dependent manner, and both were approximately ten-fold more potent at pH 9.2 than at pH 7.4, procaine inhibiting the action potential height by 50% at 0.15 mM (pH 9.2) and 1.1 mM (pH 7.4), DEAE at 4 mM (pH 9.2) and 70 mM (pH 7.4). In contrast, PABA at concentrations up to 25 mM and at either pH failed to inhibit compound action potentials, and did not modify the effects of DEAE when both drugs were given together. Procaine produced greater use-dependent block at the higher pH and at higher stimulation rates (100 Hz vs. 40 Hz); DEAE produced almost no use-dependent block. These observations suggest: 1) that DEAE might account for some of the neuropharmacologic activity of procaine in techniques that favor the accumulation of metabolites (such as those requiring large doses or prolonged infusions); and 2) that alkalinization of procaine and DEAE solutions appears to increase their potency for both resting and use-dependent block of action potentials.

Characterization of the Amicetin Biosynthesis Gene Cluster from Streptomyces vinaceusdrappus NRRL 2363 Implicates Two Alternative Strategies for Amide Bond Formation

PubMed Central

Zhang, Gaiyun; Zhang, Haibo; Li, Sumei; Xiao, Ji; Zhang, Guangtao; Zhu, Yiguang; Niu, Siwen; Ju, Jianhua

2012-01-01

Amicetin, an antibacterial and antiviral agent, belongs to a group of disaccharide nucleoside antibiotics featuring an α-(1→4)-glycoside bond in the disaccharide moiety. In this study, the amicetin biosynthesis gene cluster was cloned from Streptomyces vinaceusdrappus NRRL 2363 and localized on a 37-kb contiguous DNA region. Heterologous expression of the amicetin biosynthesis gene cluster in Streptomyces lividans TK64 resulted in the production of amicetin and its analogues, thereby confirming the identity of the ami gene cluster. In silico sequence analysis revealed that 21 genes were putatively involved in amicetin biosynthesis, including 3 for regulation and transportation, 10 for disaccharide biosynthesis, and 8 for the formation of the amicetin skeleton by the linkage of cytosine, p-aminobenzoic acid (PABA), and the terminal (+)-α-methylserine moieties. The inactivation of the benzoate coenzyme A (benzoate-CoA) ligase gene amiL and the N-acetyltransferase gene amiF led to two mutants that accumulated the same two compounds, cytosamine and 4-acetamido-3-hydroxybenzoic acid. These data indicated that AmiF functioned as an amide synthethase to link cytosine and PABA. The inactivation of amiR, encoding an acyl-CoA-acyl carrier protein transacylase, resulted in the production of plicacetin and norplicacetin, indicating AmiR to be responsible for attachment of the terminal methylserine moiety to form another amide bond. These findings implicated two alternative strategies for amide bond formation in amicetin biosynthesis. PMID:22267658

Synthesis, and structural characterization of mixed ligand copper(II) complexes of N,N,N‧,N'-tetramethylethylenediamine incorporating carboxylates

NASA Astrophysics Data System (ADS)

Batool, Syeda Shahzadi; Gilani, Syeda Rubina; Tahir, Muhammad Nawaz; Rüffer, Tobias

2017-11-01

Two ternary copper(II) complexes of N,N,N‧,N'-tetramethylethylenediamine (tmen = C6H16N2) with benzoic acid and p-aminobenzoic acid, having the formula [Cu(tmen)(BA)2(H2O)2] (1), and [Cu(tmen)(pABA)2]. 1/2 CH3OH (2) {(Where BA1- = benzoate1- (C6H5CO21-), pABA1- = p-aminobenzoate1- (p-H2NC6H5CO21-)} have been prepared and characterized by elemental combustion analysis, Uv-Visible spectroscopy, FT-IR spectroscopy, thermal, and single crystal X-ray diffraction analyses. The complex 1 is a monomer with distorted octahedral geometry. In its CuN2O4 chromophore, the Cu(II) centre is coordinated by two N atoms of a symmetrically chelating tmen ligand, by two carboxylate-O atoms from two monodentate benzoate1- anions, and by two apical aqua-O atoms, which define the distorted octahedral structure. The complex 2 is a monomer with a distorted square planar coordination geometry. In CuN2O2 chromophore, tmen is coordinated to Cu(II) ion in a chelating bidentate fashion, while the two p-aminobenzoate1- anions coordinate to Cu(II) centre through their carboxylate-O atoms in a monodentate manner, forming a square planar structure. The observed difference between asymmetric ѵas(OCO) and symmetric ѵs(OCO) stretching IR vibrations of the carboxylate moieties for 1 and 2 is 220 cm-1 and 232 cm-1, respectively, which suggests monodentate coordination mode (Δν OCO>200) of the carboxylate groups to Cu(II) ion. Thermogravimetric studies of 1 indicates removal of two water molecules at 171 °C, elimination of a tmen upto 529 °C and of two benzoate groups upto 931 °C. In tga curve of 2, methanol is lost upto 212 °C, while tmen is lost from 212 to 993 °C. The antibacterial activities of these new compounds against various bacterial strains were also investigated.

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

PubMed Central

Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

2014-01-01

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N—H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug. PMID:25075330

Simple Reversed-Phase HPLC Method with Spectrophotometric Detection for Measuring Acetaminophen-Protein Adducts in Rat Liver Samples

PubMed Central

Acharya, Miteshkumar; Lau-Cam, Cesar A.

2012-01-01

A simple reversed-phase HPLC method for measuring hepatic levels of acetaminophen- (APAP-) protein adduct following an overdose of APAP was developed. An aliquot of liver homogenate in phosphate-buffered saline pH 7.4 (PBS) was placed on a Nanosep centrifugal device, which was centrifuged to obtain a protein residue. This residue was incubated with a solution of p-aminobenzoic acid (PABA), the internal standard, and bacterial protease in PBS, transferred to a Nanosep centrifugal device, and centrifuged. A 100 μL portion of the filtrate was analyzed on a YMC-Pack ODS-AMQ C18 column, using 100 mM potassium dihydrogen phosphate-methanol-acetic acid (100 : 0.6 : 0.1) as the mobile phase, a flow rate of 1 mL/min, and photometric detection at 254 nm. PABA and APAP-cystein-S-yl (APAP-Cys) eluted at ~14.7 min and 22.7 min, respectively. Method linearity, based on on-column concentrations of APAP-Cys, was observed over the range 0.078–40 μg. Recoveries of APAP-Cys from spiked blank liver homogenates ranged from ~83% to 91%. Limits of detection and of quantification of APAP-Cys, based on column concentrations, were 0.06 μg and 0.14 μg, respectively. RSD values for interday and intraday analyses of a blank liver homogenate spiked with APAP-Cyst at three levels were, in all cases, ≤1.0% and <1.5%, respectively. The proposed method was found appropriate for comparing the antidotal properties of N-acetylcysteine and taurine in a rat model of APAP poisoning. PMID:22619591

Crystal structures of the pyrazinamide-p-aminobenzoic acid (1/1) cocrystal and the transamidation reaction product 4-(pyrazine-2-carboxamido)benzoic acid in the molten state.

PubMed

Thorat, Shridhar H; Sahu, Sanjay Kumar; Gonnade, Rajesh G

2015-11-01

The synthesis of pharmaceutical cocrystals is a strategy to enhance the performance of active pharmaceutical ingredients (APIs) without affecting their therapeutic efficiency. The 1:1 pharmaceutical cocrystal of the antituberculosis drug pyrazinamide (PZA) and the cocrystal former p-aminobenzoic acid (p-ABA), C7H7NO2·C5H5N3O, (1), was synthesized successfully and characterized by relevant solid-state characterization methods. The cocrystal crystallizes in the monoclinic space group P2₁/n containing one molecule of each component. Both molecules associate via intermolecular O-H···O and N-H···O hydrogen bonds [O···O = 2.6102 (15) Å and O-H···O = 168.3 (19)°; N···O = 2.9259 (18) Å and N-H···O = 167.7 (16)°] to generate a dimeric acid-amide synthon. Neighbouring dimers are linked centrosymmetrically through N-H···O interactions [N···O = 3.1201 (18) Å and N-H···O = 136.9 (14)°] to form a tetrameric assembly supplemented by C-H···N interactions [C···N = 3.5277 (19) Å and C-H···N = 147°]. Linking of these tetrameric assemblies through N-H···O [N···O = 3.3026 (19) Å and N-H···O = 143.1 (17)°], N-H···N [N···N = 3.221 (2) Å and N-H···N = 177.9 (17)°] and C-H···O [C···O = 3.5354 (18) Å and C-H···O = 152°] interactions creates the two-dimensional packing. Recrystallization of the cocrystals from the molten state revealed the formation of 4-(pyrazine-2-carboxamido)benzoic acid, C12H9N3O3, (2), through a transamidation reaction between PZA and p-ABA. Carboxamide (2) crystallizes in the triclinic space group P1̅ with one molecule in the asymmetric unit. Molecules of (2) form a centrosymmetric dimeric homosynthon through an acid-acid O-H···O hydrogen bond [O···O = 2.666 (3) Å and O-H···O = 178 (4)°]. Neighbouring assemblies are connected centrosymmetrically via a C-H···N interaction [C···N = 3.365 (3) Å and C-H···N = 142°] engaging the pyrazine groups to generate a linear chain. Adjacent chains are connected loosely via C-H···O interactions [C···O = 3.212 (3) Å and C-H···O = 149°] to generate a two-dimensional sheet structure. Closely associated two-dimensional sheets in both compounds are stacked via aromatic π-stacking interactions engaging the pyrazine and benzene rings to create a three-dimensional multi-stack structure.

Identification of N-Hydroxy-para-aminobenzoic acid in a cyanotic child after benzocaine exposure.

PubMed

Spiller, H A; Russell, J L; Casavant, M J; Ho, R Y; Gerona, R R

2014-11-01

Methemoglobinemia (MetHb) after exposure to benzocaine (BZC) has been reported for more than 50 years, however the pathophysiologic mechanism has not been previously established. Direct administration of BZC to blood does not produce MetHb. After topical use, due to the lipophilicity and rapid acetylation in the tissue, little BZC reaches the liver for hepatic biotransformation. However, isolated human livers have been shown to produce MetHb forming N-hydroxyl metabolites from BZC. We report a case of BZC-induced MetHb with the first identification and quantification of the reactive metabolite responsible for the oxidative stress: N-Hydroxy-Para-amino benzoic acid (N-OH-PABA). An 8 year old male was admitted to a hospital for an appendectomy. Several applications of BZC spray were used during multiple attempts at nasogastric tube placement. In various attempts to achieve local anesthesia, benzocaine spray was used in both nares and through the mouth aimed at the posterior oropharynx. The patient subsequently became cyanotic with an initial MetHb level of 32.9 %. Methylene blue was administered and the patient promptly responded with resolution of cyanosis. Blood taken within 20 min of the initial symptoms contained benzocaine (5.2ug/mL), bupivacaine (740ng/mL), lidocaine (530ng/mL), acetaminophen (12ug/mL), midazolam (60ng/mL), PABA and N-OH-PABA (35ng/mL). Serum was analyzed using Liquid Chromatography- Quadrupole Time-of-Flight Mass Spectrometry. Mass spectrometry was done using an electrospray ionization source run in negative and positive polarities. A reference standard for N-OH-PABA was synthesized for confirmation and quantification. The rare and idiopathic nature of methemoglobinemia after benzocaine use has made study of the pathophysiologic mechanism in humans difficult. Lack of understanding has brought calls for restriction of use of the widely used medication that may not be based on evidence. Our case presents several unique features: 1) benzocaine absorption after topical administration was documented with serum concentrations 2) confirmation of an in vivo formation of MetHb-forming n-hydroxyl-metabolite after benzocaine use and 3) the documentation of N-OH-PABA in humans within 20 min of MetHb post-benzocaine administration.

Binding Isotope Effects for para-Aminobenzoic Acid with Dihydropteroate Synthase from Staphylococcus aureus and Plasmodium falciparum.

PubMed

Stratton, Christopher F; Namanja-Magliano, Hilda A; Cameron, Scott A; Schramm, Vern L

2015-10-16

Dihydropteroate synthase is a key enzyme in folate biosynthesis and is the target of the sulfonamide class of antimicrobials. Equilibrium binding isotope effects and density functional theory calculations indicate that the substrate binding sites for para-aminobenzoic acid on the dihydropteroate synthase enzymes from Staphylococcus aureus and Plasmodium falciparum present distinct chemical environments. Specifically, we show that para-aminobenzoic acid occupies a more sterically constrained vibrational environment when bound to dihydropteroate synthase from P. falciparum relative to that of S. aureus. Deletion of a nonhomologous, parasite-specific insert from the plasmodial dihydropteroate synthase abrogated the binding of para-aminobenzoic acid. The loop specific to P. falciparum is important for effective substrate binding and therefore plays a role in modulating the chemical environment at the substrate binding site.

Overexpression of folate biosynthesis genes in rice (Oryza sativa L.) and evaluation of their impact on seed folate content.

PubMed

Dong, Wei; Cheng, Zhi-jun; Lei, Cai-lin; Wang, Xiao-le; Wang, Jiu-lin; Wang, Jie; Wu, Fu-qing; Zhang, Xin; Guo, Xiu-ping; Zhai, Hu-qu; Wan, Jian-min

2014-12-01

Folate (vitamin B9) deficiency is a global health problem especially in developing countries where the major staple foods such as rice contain extremely low folates. Biofortification of rice could be an alternative complement way to fight folate deficiency. In this study, we evaluated the availability of the genes in each step of folate biosynthesis pathway for rice folate enhancement in the japonica variety kitaake genetic background. The first enzymes GTP cyclohydrolase I (GTPCHI) and aminodeoxychorismate synthase (ADCS) in the pterin and para-aminobenzoate branches resulted in significant increase in seed folate content, respectively (P < 0.01). Overexpression of two closely related enzymes dihydrofolate synthase (DHFS) and folypolyglutamate synthase (FPGS), which perform the first and further additions of glutamates, produced slightly increase in seed folate content separately. The GTPCHI transgene was combined with each of the other transgenes except ADCS to investigate the effects of gene stacking on seed folate accumulation. Seed folate contents in the gene-stacked plants were higher than the individual low-folate transgenic parents, but lower than the high-folate GTPCHI transgenic lines, pointing to an inadequate supply of para-aminobenzoic acid (PABA) precursor initiated by ADCS in constraining folate overproduction in gene-stacked plants.

Effects of in vivo exposure to UV filters (4-MBC, OMC, BP-3, 4-HB, OC, OD-PABA) on endocrine signaling genes in the insect Chironomus riparius.

PubMed

Ozáez, Irene; Martínez-Guitarte, José Luis; Morcillo, Gloria

2013-07-01

There is increasing evidence indicating that several UV filters might have endocrine disruptive effects. Numerous studies have evaluated hormonal effects in vertebrates, mainly reporting estrogenic and androgenic activities in mammals and fishes. There is only limited knowledge about potential endocrine activity in invertebrate hormonal systems. In this work, the effects on endocrine signaling genes of six frequently used UV filters were investigated in Chironomus riparius, a reference organism in aquatic toxicology. The UV filters studied were: octyl-p-methoxycinnamate (OMC) also called 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4-MBC); benzophenone-3 (BP-3); 4-hidroxybenzophenone (4-HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). After in vivo exposure at different dosages, expression levels of the genes coding for the ecdysone receptor (EcR), the ultraspiracle (usp, ortholog of the RXR) and the estrogen-related receptor (ERR) were quantified by Real Time PCR. The EcR gene was significantly upregulated by 4-MBC, OMC/EHMC and OD-PABA, with a dose-related response following 24h exposure. In contrast, the benzophenones, BP-3 and 4-HB, as well as OC did not alter this gene at the same exposure conditions. The transcription profiles of the usp and ERR genes were not significantly affected, except for BP-3 that inhibited the usp gene at the highest concentration. To our knowledge, this is the first experimental evidence in invertebrates of a direct effect of UV filters on endocrine-related genes, and is consistent with the known effects on vertebrate hormonal receptor genes. The capability of 4-MBC, OMC/EHMC and OD-PABA to stimulate the expression of the ecdysone receptor, a key transcription factor for the ecdysone-genomic response in arthropods, suggests the possibility of a broad and long-term effect on this hormonal pathway. These findings strengthen the need for further research about the ecotoxicological implications of chronic exposure to these compounds in aquatic invertebrates. Copyright © 2013 Elsevier B.V. All rights reserved.

Molecular complex of lumiflavin and 2-aminobenzoic acid: crystal structure, crystal spectra, and solution properties.

PubMed

Shieh, H S; Ghisla, S; Hanson, L K; Ludwig, M L; Nordman, C E

1981-08-04

The molecular complex lumiflavin-2-aminobenzoic acid monohydrate (C13H12N4O2.C7H7NO2.H2O) crystallizes from from aqueous solution as red triclinic prisms. The space group is P1 with cell dimensions a = 9.660 A, b = 14.866 A, c = 7.045 A, alpha = 95.44 degrees , beta = 95.86 degrees, and gamma = 105.66 degrees . The crystal structure was solved by direct methods and refined by block-diagonal least-squares procedures to an R value of 0.050 on the basis of 1338 observed reflections. The structure is composed of stacks of alternating lumiflavin adn un-ionized (neutral) 2-aminobenzoic acid molecules. Two different modes of stacking interaction are observed. In one, 2-aminobenzoic acid overlaps all three of the isoalloxazine rings, at a mean distance of 3.36 A; in the other, 2-aminobenzoic acid interacts distance of 3.36 A; in the other, 2-aminobenzoic acid interacts with the pyrazine and dimethylbenzene moieties, at a distance of 3.42 A. Perpendicular to the stacking direction, the molecules form a continuous sheet. Each flavin is hydrogen bonded via O(2) and NH(3) to two symmetrically related aminobenzoates; the water of crystallization forms three hydrogen bonds, bridging two flavins, via O(4) and N(5), and one aminobenzoic acid. The red color of the crystals results from a charge-transfer transition involving stacked flavin and 2-aminobenzoic acid. The red color of the crystals results from a charge-transfer transition involving stacked flavin and 2-aminobenzoic acid molecules. Measurements of the polarized optical absorption spectra of crystals show that the transition moment direction for the long wavelength absorbance (beyond 530 nm) contains an out-of-plane component which can only arise from a charge-transfer interaction. Since the amino N does not make exceptionally close interactions with isoalloxazine atoms in either stacking mode (minimum interatomic distance 3.52 A), the charge transfer is presumed to involve pi orbitals of the 2-aminobenzoic acid donor.

Novel nanocomposite Kevlar fabric membranes: Fabrication characterization, and performance in oil/water separation

NASA Astrophysics Data System (ADS)

Karimnezhad, Hanieh; Rajabi, Laleh; Salehi, Ehsan; Derakhshan, Ali Ashraf; Azimi, Sara

2014-02-01

Nanocomposite membranes with hydrophilic surface were fabricated for separation of oil (n-hexane) from oil/water emulsion. Three different nanomaterials namely, para-aminobenzoate alumoxane (PAB-A), boehmite-epoxide and polycitrate alumoxane (PC-A) were coated on the Kevlar fabric (support), according to a three-step dip-coating protocol. FTIR, SEM, TEM, UV/vis spectrophotometer, and wettability analyses were used to characterize the composite membranes. The three coating layers interacted chemically with one another and also physically with the Kevlar fabric. Water uptake measurements indicated that the membrane is a hydrophilic one. SEM and TEM analyses showed the smooth surface of the composite membrane and three-dimensional dendrimeric hyper-branched structure of (PC-A), respectively. A dead-end filtration setup was applied to test the membranes performance under natural gravity force. Effect of pH as an important variable affecting separation process was investigated with the neutral pH provided the optimum condition for the separation. Oil rejection and permeate fluxes were also monitored. The optimum flux and rejection obtained, were 7392 (Lm-2 h-1) and 89.06% at pH 7, respectively. Fouling occurred as a gel layer on the membrane surface. The deposited oil droplets on the surface of the membrane were successfully washed away with satisfactory permeate flux recovery (FRR = 88.88% at neutral pH), using hot distilled water and acidic solution as eluents.

Ultraviolet filters differentially impact the expression of key endocrine and stress genes in embryos and larvae of Chironomus riparius.

PubMed

Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis

2016-07-01

Several organic UV filters have hormonal activity in vertebrates, as demonstrated in fishes, rodents and human cells. Despite the accumulation of filter contaminants in aquatic systems, research on their effects on the endocrine systems of freshwaters invertebrates is scarce. In this work, the effects of five frequently used UV filters were investigated in embryos and larvae of Chironomus riparius, which is a reference organism in ecotoxicology. LC50 values for larvae as well as the percentage of eclosion of eggs were determined following exposures to: octyl-p-methoxycinnamate (OMC) also known as 2-ethylhexyl-4-methoxycinnamate (EHMC); 4-methylbenzylidene camphor (4MBC); 4-hydroxybenzophenone (4HB); octocrylene (OC); and octyldimethyl-p-aminobenzoate (OD-PABA). To assess sublethal effects, expression levels of the genes coding for the ecdysone receptor (EcR) and heat shock protein HSP70 were investigated as biomarkers for endocrine and stress effects at the cellular level. Life-stage-dependent sensitivity was found. In embryos, all of the UV filters provoked a significant overexpression of EcR at 24h after exposure. OC, 4MBC and OD-PABA also triggered transcriptional activation of the hsp70 stress gene in embryos. In contrast, in larvae, only 4MBC and OMC/EHMC increased EcR and hsp70 mRNA levels and OD-PABA upregulated only the EcR gene. These results revealed that embryos are particularly sensitive to UV filters, which affect endocrine regulation during development. Most UV filters also triggered the cellular stress response, and thus exhibit proteotoxic effects. The differences observed between embryos and larvae and the higher sensitivity of embryos highlight the importance of considering different life stages when evaluating the environmental risks of pollutants, particularly when analyzing endocrine effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Acemetacin cocrystal structures by powder X-ray diffraction.

PubMed

Bolla, Geetha; Chernyshev, Vladimir; Nangia, Ashwini

2017-05-01

Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM), p -aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM-NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid-amide dimer three-point synthon R 3 2 (9) R 2 2 (8) R 3 2 (9) with three different syn amides (VLM, 2HP and caprolactam). The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I) or syn (type II). ACM hydrate, ACM-NAM, ACM-NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP) surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O⋯H, N⋯H, Cl⋯H and C⋯H interactions. The physicochemical properties of these cocrystals are under study.

Acemetacin cocrystal structures by powder X-ray diffraction

PubMed Central

Bolla, Geetha

2017-01-01

Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM), p-aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthon R 3 2(9)R 2 2(8)R 3 2(9) with three different syn amides (VLM, 2HP and caprolactam). The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I) or syn (type II). ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP) surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O⋯H, N⋯H, Cl⋯H and C⋯H interactions. The physicochemical properties of these cocrystals are under study. PMID:28512568

Growth of Pseudomonas C on C1 Compounds: Continuous Culture

PubMed Central

Battat, E.; Goldberg, I.; Mateles, R. I.

1974-01-01

Pseudomonas C was grown in continuous culture on methanol, formaldehyde, or formate as sole carbon source. On methanol μmax = 0.49/h and yield constant (Y) = 0.54; on formaldehyde and on unsupplemented media, μmax was about 0.2/h and Y was 0.15, whereas addition of p-aminobenzoic acid, folic acid, serine, or glycine to the medium raised Y to about 0.26 to 0.29, and addition of p-aminobenzoic acid, folic acid, serine, nicotinamide adenine dinucleotide, and Tween 80 raised the yield to 0.35. On formate and on unsupplemented media, μmax = 0.2/h and Y = 0.02, whereas addition of 0.1 mM p-aminobenzoic acid increased μmax to about 0.47 and Y to about 0.23. At low cell concentrations or growth rates a beneficial effect of CO2 was observed. Formaldehyde or formate, when added together with methanol, were utilized simultaneously with the methanol. PMID:4375436

Development of an activated carbon filter to remove NO2 and HONO in indoor air.

PubMed

Yoo, Jun Young; Park, Chan Jung; Kim, Ki Yeong; Son, Youn-Suk; Kang, Choong-Min; Wolfson, Jack M; Jung, In-Ha; Lee, Sung-Joo; Koutrakis, Petros

2015-05-30

To obtain the optimum removal efficiency of NO2 and HONO by coated activated carbon (ACs), the influencing factors, including the loading rate, metal and non-metal precursors, and mixture ratios, were investigated. The NOx removal efficiency (RE) for K, with the same loading (1.0 wt.%), was generally higher than for those loaded with Cu or Mn. The RE of NO2 was also higher when KOH was used as the K precursor, compared to other K precursors (KI, KNO3, and KMnO4). In addition, the REs by the ACs loaded with K were approximately 38-55% higher than those by uncoated ACs. Overall, the REs (above 95%) of HONO and NOx with 3% KOH were the highest of the coated AC filters that were tested. Additionally, the REs of NOx and HONO using a mixing ratio of 6 (2.5% PABA (p-aminobenzoic acid)+6% H3PO4):4 (3% KOH) were the highest of all the coatings tested (both metal and non-metal). The results of this study show that AC loaded with various coatings has the potential to effectively reduce NO2 and HONO levels in indoor air. Copyright © 2015 Elsevier B.V. All rights reserved.

Magnetic whiskers of p-aminobenzoic acid and their use for preparation of filled and microchannel silicone rubbers

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

Semenov, V. V., E-mail: vvsemenov@iomc.ras.ru; Loginova, V. V.; Zolotareva, N. V.

A thin cobalt layer has been formed on the surface of p-aminobenzoic acid whiskers by chemical vapor deposition (CVD). The metallized crystals have been oriented in liquid polydimethylsiloxane rubber by applying a dc magnetic field. After vulcanization, the filler has been removed by processing in an alcohol solution of trifluoroacetic acid. The cobalt deposition on the surface of the organic compound and the properties of metallized whiskers are investigated by optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM).

Determination of monosaccharides derivatized with 2-aminobenzoic Acid by capillary electrophoresis.

PubMed

Abo, Mitsuru; He, Li-Ping; Sato, Kae; Okubo, Akira

2013-01-01

Reducing monosaccharides were derivatized with 2-aminobenzoic acid (2-AA) through reductive amination using sodium cyanoborohydride as a reductant, and the derivatives were separated by capillary zone electrophoresis with UV detection using 50 mM sodium phosphate (pH 5.5) or 150 mM sodium borate-50 mM sodium phosphate (pH 7.0) running buffer. The derivatives of monosaccharides, which are major components of various carbohydrate materials, were completely separated within 25 min.

40 CFR 721.2900 - Substituted aminobenzoic acid ester (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted aminobenzoic acid ester... Specific Chemical Substances § 721.2900 Substituted aminobenzoic acid ester (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance substituted aminobenzoic...

Indium tin oxide with zwitterionic interfacial design for biosensing applications in complex matrices

NASA Astrophysics Data System (ADS)

Darwish, Nadia T.; Alias, Yatimah; Khor, Sook Mei

2015-01-01

Biosensing interfaces consisting of linker molecules (COOH or NH2) and charged, antifouling moieties ((sbnd SO3- and N+(Me)3) for biosensing applications were prepared for the first time by the in situ deposition of mixtures of aryl diazonium cations on indium tin oxide (ITO) electrodes. A linker molecule is required for the attachment of biorecognition molecules (e.g., antibodies, enzymes, DNA chains, and aptamers) close to the transducer surface. The attached molecules improve the biosensing sensitivity and also provide a short response time for analyte detection. Thus, the incorporation of a linker and antifouling molecules is an important interfacial design for both affinity and enzymatic biosensors. The reductive adsorption behavior and electrochemical measurement were studied for (1) an individual compound and (2) a mixture of antifouling zwitterionic molecules together with linker molecules [combination 1: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 1,4-phenylenediamine (PPD); combination 2: 4-sulfophenyl (SP), 4-trimethylammoniophenyl (TMAP), and 4-aminobenzoic acid (PABA)] of aryl diazonium cations grafted onto an ITO electrode. The mixture ratios of SP:TMAP:PPD and SP:TMAP:PABA that provided the greatest resistance to non-specific protein adsorptions of bovine serum albumin labeled with fluorescein isothiocyanate (BSA-FITC) and cytochrome c labeled with rhodamine B isothiocyanate (RBITC-Cyt c) were determined by confocal laser scanning microscopy (CLSM). For the surface antifouling study, we used 2-[2-(2-methoxyethoxy) ethoxy]acetic acid (OEG) as a standard control because of its prominent antifouling properties. Surface compositions of combinations 1 and 2 were characterized using X-ray photoelectron spectroscopy (XPS). Field-emission scanning electron microscopy (FE-SEM) was used to characterize the morphology of the grafted films to confirm the even distribution between linker and antifouling molecules grafted onto the ITO surfaces. Combination 1 (SP:TMAP:PPD) with a ratio of 0.5:1.5:0.37 exhibited the best antifouling capability with respect to resisting the nonspecific adsorption of proteins.

40 CFR 721.5286 - Benzenediazonium, [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol...

Code of Federal Regulations, 2010 CFR

2010-07-01

...) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted)azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized...

40 CFR 721.5286 - Benzenediazonium, [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol...

Code of Federal Regulations, 2011 CFR

2011-07-01

...) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted)azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized...

Anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) via benzoyl-coenzyme A (CoA) and cyclohex-1-enecarboxyl-CoA in a denitrifying bacterium.

PubMed Central

Lochmeyer, C; Koch, J; Fuchs, G

1992-01-01

The enzymes catalyzing the initial reactions in the anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) were studied with a denitrifying Pseudomonas sp. anaerobically grown with 2-aminobenzoate and nitrate as the sole carbon and energy sources. Cells grown on 2-aminobenzoate are simultaneously adapted to growth with benzoate, whereas cells grown on benzoate degrade 2-aminobenzoate several times less efficiently than benzoate. Evidence for a new reductive pathway of aromatic metabolism and for four enzymes catalyzing the initial steps is presented. The organism contains 2-aminobenzoate-coenzyme A ligase (2-aminobenzoate-CoA ligase), which forms 2-aminobenzoyl-CoA. 2-Aminobenzoyl-CoA is then reductively deaminated to benzoyl-CoA by an oxygen-sensitive enzyme, 2-aminobenzoyl-CoA reductase (deaminating), which requires a low potential reductant [Ti(III)]. The specific activity is 15 nmol of 2-aminobenzoyl-CoA reduced min-1 mg-1 of protein at an optimal pH of 7. The two enzymes are induced by the substrate under anaerobic conditions only. Benzoyl-CoA is further converted in vitro by reduction with Ti(III) to six products; the same products are formed when benzoyl-CoA or 2-aminobenzoyl-CoA is incubated under reducing conditions. Two of them were identified preliminarily. One product is cyclohex-1-enecarboxyl-CoA, the other is trans-2-hydroxycyclohexane-carboxyl-CoA. The complex transformation of benzoyl-CoA is ascribed to at least two enzymes, benzoyl-CoA reductase (aromatic ring reducing) and cyclohex-1-enecarboxyl-CoA hydratase. The reduction of benzoyl-CoA to alicyclic compounds is catalyzed by extracts from cells grown anaerobically on either 2-aminobenzoate or benzoate at almost the same rate (10 to 15 nmol min-1 mg-1 of protein). In contrast, extracts from cells grown anaerobically on acetate or grown aerobically on benzoate or 2-aminobenzoate are inactive. This suggests a sequential induction of the enzymes. Images PMID:1592816

Anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) via benzoyl-coenzyme A (CoA) and cyclohex-1-enecarboxyl-CoA in a denitrifying bacterium.

PubMed

Lochmeyer, C; Koch, J; Fuchs, G

1992-06-01

The enzymes catalyzing the initial reactions in the anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) were studied with a denitrifying Pseudomonas sp. anaerobically grown with 2-aminobenzoate and nitrate as the sole carbon and energy sources. Cells grown on 2-aminobenzoate are simultaneously adapted to growth with benzoate, whereas cells grown on benzoate degrade 2-aminobenzoate several times less efficiently than benzoate. Evidence for a new reductive pathway of aromatic metabolism and for four enzymes catalyzing the initial steps is presented. The organism contains 2-aminobenzoate-coenzyme A ligase (2-aminobenzoate-CoA ligase), which forms 2-aminobenzoyl-CoA. 2-Aminobenzoyl-CoA is then reductively deaminated to benzoyl-CoA by an oxygen-sensitive enzyme, 2-aminobenzoyl-CoA reductase (deaminating), which requires a low potential reductant [Ti(III)]. The specific activity is 15 nmol of 2-aminobenzoyl-CoA reduced min-1 mg-1 of protein at an optimal pH of 7. The two enzymes are induced by the substrate under anaerobic conditions only. Benzoyl-CoA is further converted in vitro by reduction with Ti(III) to six products; the same products are formed when benzoyl-CoA or 2-aminobenzoyl-CoA is incubated under reducing conditions. Two of them were identified preliminarily. One product is cyclohex-1-enecarboxyl-CoA, the other is trans-2-hydroxycyclohexane-carboxyl-CoA. The complex transformation of benzoyl-CoA is ascribed to at least two enzymes, benzoyl-CoA reductase (aromatic ring reducing) and cyclohex-1-enecarboxyl-CoA hydratase. The reduction of benzoyl-CoA to alicyclic compounds is catalyzed by extracts from cells grown anaerobically on either 2-aminobenzoate or benzoate at almost the same rate (10 to 15 nmol min-1 mg-1 of protein). In contrast, extracts from cells grown anaerobically on acetate or grown aerobically on benzoate or 2-aminobenzoate are inactive. This suggests a sequential induction of the enzymes.

Non-porous membrane-assisted liquid-liquid extraction of UV filter compounds from water samples.

PubMed

Rodil, Rosario; Schrader, Steffi; Moeder, Monika

2009-06-12

A method for the determination of nine UV filter compounds [benzophenone-3 (BP-3), isoamyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene (OC), butyl methoxydibenzoylmethane, ethylhexyl dimethyl p-aminobenzoate (OD-PABA), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate and homosalate] in water samples was developed and evaluated. The procedure includes non-porous membrane-assisted liquid-liquid extraction (MALLE) and LC-atmospheric pressure photoionization (APPI)-MS/MS. Membrane bags made of different polymeric materials were examined to enable a fast and simple extraction of the target analytes. Among the polymeric materials tested, low- and high-density polyethylene membranes proved to be well suited to adsorb the analytes from water samples. Finally, 2 cm length tailor-made membrane bags were prepared from low-density polyethylene in order to accommodate 100 microL of propanol. The fully optimised protocol provides recoveries from 76% to 101% and limits of detection (LOD) between 0.4 ng L(-1) (OD-PABA) and 16 ng L(-1) (EHMC). The interday repeatability of the whole protocol was below 18%. The effective separation of matrix molecules was proved by only marginal matrix influence during the APPI-MS analysis since no ion suppression effects were observed. During the extraction step, the influence of the matrix was only significant when non-treated wastewater was analysed. The analysis of lake water indicated the presence of seven UV filter compounds included in this study at concentrations between 40 ng L(-1) (BP-3) and 4381 ng L(-1) (OC). In non-treated wastewater several UV filters were also detected at concentration levels as high as 5322 ng L(-1) (OC).

Human COQ9 Rescues a coq9 Yeast Mutant by Enhancing Coenzyme Q Biosynthesis from 4-Hydroxybenzoic Acid and Stabilizing the CoQ-Synthome

PubMed Central

He, Cuiwen H.; Black, Dylan S.; Allan, Christopher M.; Meunier, Brigitte; Rahman, Shamima; Clarke, Catherine F.

2017-01-01

Coq9 is required for the stability of a mitochondrial multi-subunit complex, termed the CoQ-synthome, and the deamination step of Q intermediates that derive from para-aminobenzoic acid (pABA) in yeast. In human, mutations in the COQ9 gene cause neonatal-onset primary Q10 deficiency. In this study, we determined whether expression of human COQ9 could complement yeast coq9 point or null mutants. We found that expression of human COQ9 rescues the growth of the temperature-sensitive yeast mutant, coq9-ts19, on a non-fermentable carbon source and increases the content of Q6, by enhancing Q biosynthesis from 4-hydroxybenzoic acid (4HB). To study the mechanism for the rescue by human COQ9, we determined the steady-state levels of yeast Coq polypeptides in the mitochondria of the temperature-sensitive yeast coq9 mutant expressing human COQ9. We show that the expression of human COQ9 significantly increased steady-state levels of yeast Coq4, Coq6, Coq7, and Coq9 at permissive temperature. Human COQ9 polypeptide levels persisted at non-permissive temperature. A small amount of the human COQ9 co-purified with tagged Coq6, Coq6-CNAP, indicating that human COQ9 interacts with the yeast Q-biosynthetic complex. These findings suggest that human COQ9 rescues the yeast coq9 temperature-sensitive mutant by stabilizing the CoQ-synthome and increasing Q biosynthesis from 4HB. This finding provides a powerful approach to studying the function of human COQ9 using yeast as a model. PMID:28736527

Carboxymethylcellulose-tetrahydrocurcumin conjugates for colon-specific delivery of a novel anti-cancer agent, 4-amino tetrahydrocurcumin.

PubMed

Plyduang, Thipapun; Lomlim, Luelak; Yuenyongsawad, Supreeya; Wiwattanapatapee, Ruedeekorn

2014-10-01

Several curcumin derivatives are now becoming increasingly of interest because of their bioactive attributes, especially their action as antioxidants and anti-carcinogenic activities. Tetrahydrocurcumin (THC), an active metabolite of curcumin, was selected to be a proper starting material for the work presented here as it is stable in physiological pH and has the typical pharmacological properties of curcumin. We have now reported that novel synthesized water-soluble polymeric macromolecule prodrugs can specifically deliver the drug to the colon. To study the drug loading and drug release, THC was conjugated with a hydrophilic polymer, carboxymethylcellulose (CMC) with the degree of substitution (DS) values of 0.7 and 1.2. THC was also attached to two different spacers including p-aminobenzoic acid (PABA) and p-aminohippuric acid (PAH) via an azo bond that was cleaved by the azoreductase activities of colonic bacteria. The novel active molecule, 4-amino-THC, was readily released from the conjugates in the colon (>62% within 24h) with only very small amounts released in the upper GI tract (<12% over 12h). The polymer conjugates showed chemical stability at various pH values along the gastrointestinal tract and increased water solubility of up to 5mg/mL. 4-Amino-THC demonstrated cytotoxic ability against the human colon adenocarcinoma cell lines (HT-29) with an IC50 of 28.67 ± 1.01 μg/mL, and even greater selectivity (∼ 4 folds) to inhibit HT-29 cells than to normal human colon epithelial cell lines while curcumin was a non-selective agent against both cell lines. Our study has demonstrated that the use of THC-CMC conjugates may be a promising colon-specific drug delivery system with its sustained release in the colon to be an effective treatment for colonic cancer. Copyright © 2014 Elsevier B.V. All rights reserved.

Study of the growth and pyroelectric properties of TGS crystals doped with aniline-family dipolar molecules

NASA Astrophysics Data System (ADS)

Zhang, Kecong; Song, Jiancheng; Wang, Min; Fang, Changshui; Lu, Mengkai

1987-04-01

TGS crystals doped with aniline-family dipolar molecules (aniline, 2-aminobenzoic acid, 3-aminobenzoic acid, 3-aminobenzene-sulphonic acid, 4-aminobenzenesulphonic acid and 4-nitroraniline) have been grown by the slow-cooling solution method. The influence of these dopants on the growth habits, crystal morphology pyroelectric properties, and structure parameters of TGS crystals has been systematically investigated. The effects of the domain structure of the seed crystal on the pyroelectric properties of the doped crystals have been studied. It is found that the spontaneous polarization (P), pyroelectric coefficient (lambda), and internal bias field of the doped crystals are slightly higher than those of the pure TGS, and the larger the dipole moment of the dopant molecule, the higher the P and lambda of the doped TGS crystal.

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

Silva, Camila F.N.; Lazarin, Angélica M., E-mail: amlazarin2@uem.br; Sernaglia, Rosana L.

Graphical abstract: Scanning electron microscopy photographs of calcium phosphate (a) and intercalated with p-aminobenzoic acid (b). Highlights: ► Calcium phosphate was intercalated with p-aminobenzoic acid. ► Guest molecule contains nitrogen and oxygen atoms from amine and carboxylic groups. ► These basic centers are potentially useful for cation coordination in ethanol solution. ► Crystal morphology of compounds is lamellar, it agrees with expected structural characteristics. -- Abstract: Crystalline lamellar calcium phosphate retained 4-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1033 and 1010 cm{sup −1} interval confirmed the presence of the phosphonate groups attached to themore » inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 712 and 1578 pm for the original and the intercalated compounds, respectively. Solid-state {sup 31}P nuclear magnetic resonance spectra presented only one peak for the phosphate groups attached to the main inorganic polymeric structure near −2.4 ppm. The adsorption isotherms from ethanol gave the maximum adsorption capacities of 6.44 and 3.34 mmol g{sup −1} for nickel and cobalt, respectively, which stability constant and distribution coefficient followed Co > Ni.« less

PABA/NO lead optimization: Improved targeting of cytotoxicity to glutathione S-transferase P1-overexpressing cancer cells.

PubMed

Kim, Youseung; Maciag, Anna E; Cao, Zhao; Deschamps, Jeffrey R; Saavedra, Joseph E; Keefer, Larry K; Holland, Ryan J

2015-08-01

PABA/NO [O(2)-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino) diazen-1-ium-1,2-diolate] is a nitric oxide (NO)-releasing arylating agent designed to be selectively activated by reaction with glutathione (GSH) on catalysis by glutathione S-transferase P1 (GSTP1), an enzyme frequently overexpressed in cancer cells. PABA/NO has proven active in several cancer models in vitro and in vivo, but its tendency to be metabolized via a variety of pathways, some that generate inactive metabolites and hydrolysis products, limits its potential as a drug. Here we show that a simple replacement of cyano for nitro at the 4 position to give compound 4b ('p-cyano-PABA/NO') has the dual effect of slowing the undesired side reactions while enhancing the proportion of NO release and arylating activity on catalysis by GSTP1. Compound 4b showed increased resistance to hydrolysis and uncatalyzed reaction with GSH, along with a more favorable product distribution in the presence of GSTP1. It also showed significant proapoptotic activity. The data suggest p-cyano-PABA/NO to be a more promising prodrug than PABA/NO, with better selectivity toward cancer cells. Published by Elsevier Ltd.

Environmental occurrence and ecological risk assessment of organic UV filters in marine organisms from Hong Kong coastal waters.

PubMed

Sang, Ziye; Leung, Kelvin Sze-Yin

2016-10-01

Organic UV filters, now considered to be emerging contaminants in aquatic ecosystems, are being intensively tracked in environmental waters worldwide. However, their environmental fate and impact of these contaminants on marine organisms remains largely unknown, especially in Asia. This work elucidates the occurrence and the ecological risks of seven UV filters detected in farmed fish, wild mussels and some other wild organisms collected from local mariculture farms in Hong Kong. For all of the organisms, ethylhexyl methoxycinnamate (EHMC) and octyl dimethyl p-aminobenzoic acid (OD-PABA) were the predominant contaminants with the highest concentrations up to 51.3 and 24.1ng/g (dw), respectively; lower levels were found for benzophenone-8 (BP-8), octocrylene (OC) and benzophenone-3 (BP-3) from

Drug resistance in trypanosomes; selective interference with trypanocidal action

PubMed Central

Williamson, J.

1959-01-01

Selective reversal of the trypanocidal action of carboxylated arsenicals by p-aminobenzoic acid and of melaminyl arsenicals and diamidines by melamine has been demonstrated in vivo and in vitro. The structural specificity of these reversal phenomena is high, and suggests preferential adsorption of the antagonist during a reversible primary drug fixation stage. Thiols antagonized neutral, carboxylated and melaminyl aromatic arsenicals equally, but not diamidines; p-aminobenzoic acid antagonism is specific for carboxylated arsenicals, and melamine antagonizes only the melaminyl arsenicals and the diamidines. These reversals reflect the pattern of crossresistance behaviour and suggest that cellular structures associated with a reversible stereospecific drug adsorption phase are modified during the development of resistance. PMID:13844960

Vitamins for enhancing plant resistance.

PubMed

Boubakri, Hatem; Gargouri, Mahmoud; Mliki, Ahmed; Brini, Faiçal; Chong, Julie; Jbara, Moez

2016-09-01

This paper provides an overview on vitamins with inducing activities in plants, the molecular and cellular mechanisms implicated, and the hormonal signalling-network regulating this process. Moreover, it reports how vitamins might be part of the molecular events linked to induced resistance by the conventional elicitors. Induced resistance (IR), exploiting the plant innate-defense system is a sustainable strategy for plant disease control. In the last decade, vitamins have been proven to act as inducers of disease resistance, and these findings have received an important attention owing to their safety and cost effectiveness. Vitamins, including thiamine (TH, vitamin B1), riboflavin (RF, vitamin B2), menadione sodium bisulfite (MSB, vitamin K3), Para-aminobenzoic acid (PABA, vitamin Bx), and folic acid (FA, vitamin B9) provided an efficient protection against a wide range of pathogens through the modulation of specific host-defense facets. However, other vitamins, such as ascorbic acid (AA, vitamin C) and tocopherols (vitamin E), have been shown to be a part of the molecular mechanisms associated to IR. The present review is the first to summarize what vitamins are acting as inducers of disease resistance in plants and how could they be modulated by the conventional elicitors. Thus, this report provides an overview on the protective abilities of vitamins and the molecular and cellular mechanisms underlying their activities. Moreover, it describes the hormonal-signalling network regulating vitamin-signal transduction during IR. Finally, a biochemical model describing how vitamins are involved in the establishment of IR process is discussed.

Noninvasive Measurement of Murine Hepatic Acetyl-CoA 13C-Enrichment Following Overnight Feeding with 13C-Enriched Fructose and Glucose

PubMed Central

Carvalho, Filipa; Duarte, Joao; Simoes, Ana Rita; Cruz, Pedro F.; Jones, John G.

2013-01-01

The 13C-isotopomer enrichment of hepatic cytosolic acetyl-CoA of overnight-fed mice whose drinking water was supplemented with [U-13C]fructose, and [1-13C]glucose and p-amino benzoic acid (PABA) was quantified by 13C NMR analysis of urinary N-acetyl-PABA. Four mice were given normal chow plus drinking water supplemented with 5% [1-13C]glucose, 2.5% [U-13C]fructose, and 2.5% fructose (Solution 1) overnight. Four were given chow and water containing 17.5% [1-13C]glucose, 8.75% [U-13C]fructose and 8.75% fructose (Solution 2). PABA (0.25%) was present in both studies. Urinary N-acetyl-PABA was analyzed by 13C NMR. In addition to [2-13C]- and [1,2-13C]acetyl isotopomers from catabolism of [U-13C]fructose and [1-13C]glucose to acetyl-CoA, [1-13C]acetyl was also found indicating pyruvate recycling activity. This precluded precise estimates of [1-13C]glucose contribution to acetyl-CoA while that of [U-13C]fructose was unaffected. The fructose contribution to acetyl-CoA from Solutions 1 and 2 was 4.0 ± 0.4% and 10.6 ± 0.6%, respectively, indicating that it contributed to a minor fraction of lipogenic acetyl-CoA under these conditions. PMID:23841082

Separation of 2-aminobenzoic acid-derivatized glycosaminoglycans and asparagine-linked glycans by capillary electrophoresis.

PubMed

Sato, Kae; Sato, Kiichi; Okubo, Akira; Yamazaki, Sunao

2005-01-01

A capillary electrophoresis method was developed for the analysis of oligosaccharides combined with derivatization with 2-aminobenzoic acid. Glycosaminoglycan delta-disaccharides were effectively resolved on a fused-silica capillary tube using 150 mM borate, pH 8.5, as a running electrolyte solution. This analytical method was applied to the identification of glycosaminoglycan in combination with enzymatic digestion. The separation of N-glycans or glucose-oligomers was performed with a phosphate buffer containing polyethylene glycol or borate as an electrolyte solution. This method is expected to be useful in the determination of oligosaccharide structures in a glycoprotein.

Simultaneous analysis and monitoring of 16 UV filters in cosmetics by high-performance liquid chromatography.

PubMed

Kim, Dojung; Kim, Sangseop; Kim, Seol-A; Choi, Myoengsin; Kwon, Kyoung-Jin; Kim, Mijeong; Kim, Dong-Sup; Kim, Seung-Hee; Choi, Bo-Kyung

2012-01-01

Sixteen UV filters were simultaneously analyzed using the high-performance liquid chromatographic method. They were drometrizole (USAN Drometrizole), 4-methylbenzylidene camphor (USAN Enzacamene), menthyl anthranilate (USAN Menthyl anthranilate), benzophenone-3 (USAN Oxybenzone), benzophenone-8 (USAN Dioxybenzone), butyl methoxydibenzoylmethane (USAN Avobenzone), ethylhexyl triazone (USAN Octyl triazone), octocrylene (USAN Octocrylene), ethylhexyl dimethyl p-aminobenzoic acid (USAN Padimate O), ethylhexyl methoxycinnamate (USAN Octinoxate), p-aminobenzoic acid (USAN Aminobenzoic acid), 2-phenylbenzimidazole-5-sulfonic acid (USAN Ensulizole), isoamyl p-methoxycinnamate (USAN Amiloxate), and recent UV filters such as diethylhexyl butamidotriazone (USAN Iscotrizinol), methylene bis-benzotriazolyl tetramethylbutylphenol (USAN Bisoctrizole), and terephthalylidene dicamphor sulfonic acid (USAN Ecamsule). Separation of the UV filters was carried out in a C(18) column with a gradient of methanol-phosphate buffer, and the UV detection was at 300, 320, or 360 nm without any interference. The limits of detection were between 0.08 and 1.94 μg/ml, and the limits of quantitation were between 0.24 and 5.89 μg/ml. The extracting solvent for the UV filters was methanol, except for ethylhexyl triazone and methylene bis-benzotriazolyl tetramethylbutylphenol, which were prepared with tetrahydrofuran. The recoveries from spiked samples were between 94.90% and 116.54%, depending on the matrixes used. The developed method was applied to 23 sunscreens obtained from local markets, and the results were acceptable to their own criteria and to maximum authorized concentrations. Consequently, these results would provide a simple extracting method and a simultaneous determination for various UV filters, which can improve the quality control process as well as the environmental monitoring of sunscreens.

Development of a lateral flow dipstick immunoassay for evaluation of folate levels in maize.

PubMed

Liang, Qiuju; Yi, Chen; Jiang, Ling; Tan, Guiyu; Zhang, Chunyi; Wang, Baomin

2017-09-01

Folates (vitamin B9) are essential for all organisms as cofactors for one-carbon metabolism. However, measurement of folates is technically complicated and time-consuming. In this study, we developed a dipstick immunoassay using a folate-specific monoclonal antibody (mAb), allowing rapid and low-cost detection of folates. The indicator range of the dipstick for 5-formylterahydrofolate (5-CHO-THF), 5-methyltetrahydrofolate (5-CH 3 -THF) and their polyglutamyl forms was 100-200 ng mL -1 ; moreover, no cross-reactivity was observed with tetrahydrofolate (THF) or 5,10-methenyltetrahydrofolate (5,10-CH=THF) at 500 ng mL -1 , or with the folate precursors pterin-6-COOH, p-aminobenzoate (pABA), and L-glutamate, or with the folate analogues methotrexate and 10-formyltetrahydrofolate (10-CHO-THF) at up to 1000 ng mL -1 . The dipstick immunoassay was tested in maize seeds; the results classified the seeds into those with low, moderate, and high levels of folates, and were in agreement with those of liquid chromatography-mass spectrometry. Thus, we conclude that the dipstick assay will provide a versatile tool to facilitate large-scale screening of maize rich in folates. Graphical Abstract The dipstick based immunoassay for analyzing folate level in maize.

Skin metabolism of aminophenols: Human keratinocytes as a suitable in vitro model to qualitatively predict the dermal transformation of 4-amino-2-hydroxytoluene in vivo

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

Goebel, C.; Hewitt, N.J.; Kunze, G.

2009-02-15

4-Amino-2-hydroxytolune (AHT) is an aromatic amine ingredient in oxidative hair colouring products. As skin contact occurs during hair dyeing, characterisation of dermal metabolism is important for the safety assessment of this chemical class. We have compared the metabolism of AHT in the human keratinocyte cell line HaCaT with that observed ex-vivo in human skin and in vivo (topical application versus oral (p.o.) and intravenous (i.v.) route). Three major metabolites of AHT were excreted, i.e. N-acetyl-AHT, AHT-sulfate and AHT-glucuronide. When 12.5 mg/kg AHT was applied topically, the relative amounts of each metabolite were altered such that N-acetyl-AHT product was the majormore » metabolite (66% of the dose in comparison with 37% and 32% of the same applied dose after i.v. and p.o. administration, respectively). N-acetylated products were the only metabolites detected in HaCaT cells and ex-vivo whole human skin discs for AHT and p-aminophenol (PAP), an aromatic amine known to undergo N-acetylation in vivo. Since N-acetyltransferase 1 (NAT1) is the responsible enzyme, kinetics of AHT was further compared to the standard NAT1 substrate p-aminobenzoic acid (PABA) in the HaCaT model revealing similar values for K{sub m} and V{sub max}. In conclusion NAT1 dependent dermal N-acetylation of AHT represents a 'first-pass' metabolism effect in the skin prior to entering the systemic circulation. Since the HaCaT cell model represents a suitable in vitro assay for addressing the qualitative contribution of the skin to the metabolism of topically-applied aromatic amines it may contribute to a reduction in animal testing.« less

Sorption and degradation of selected organic UV filters (BM-DBM, 4-MBC, and OD-PABA) in laboratory water-sediment systems.

PubMed

Li, Sheng; Lu, Guanghua; Xie, Zhengxin; Ding, Jiannan; Liu, Jianchao; Li, Yi

2016-05-01

Organic UV filters that have been widely used in sunscreens and other personal care products have drawn much public concern because of their widespread contamination in the environment and their potential ecological risks to ecosystems. We selected three UV filters with high frequency of detection in the environment, namely butyl methoxy dibenzoylmethane (BM-DBM), ethylhexyl dimethyl p-aminobenzoate (OD-PABA), and 4-methylbenzylidene camphor (4-MBC), to investigate the sorption and degradation behaviors of these compounds in lab-scale water-sediment systems set up with natural water and sediment samples collected from different rivers and lakes (i.e., Yangtze River, Qinhuai River, Xuanwu Lake, and Mochou Lake) in Nanjing, East China. The sorption isotherms of these UV filters were well described by the Freundlich equation (C s   = K f  × C w (n) ). The sorption of three UV filters in four sediments was all linear or close to it, with n values between 0.92 and 1.13. A moderate to strong sorption affinity was observed for these compounds, and the sorption appears to be irreversible. For the combined sorption and degradation studies, sorption was found to be a primary mechanism for the disappearance of these UV filters from the water phase, and biotransformation appears to be the predominant factor for the degradation of the target compounds in the water-sediment systems. All three UV filters were found to be slightly resistant to the microbes in these systems, with DT50total and DT90total values-the disappearance time (DT) describes the time in which the initial total mass of the UV filters in the whole system is reduced by 50 and 90 %-ranging between 18 and 31 days and 68 and 101 days, respectively.

BIOCHEMICAL AND GENETIC CHARACTERIZATION OF AN EARLY STEP IN A NOVEL PATHWAY FOR THE BIOSYNTHESIS OF AROMATIC AMINO ACIDS AND P-AMINOBENZOIC ACID IN THE ARCHAEON METHANOCOCCUS MARIPALUDIS

EPA Science Inventory

Methanococcus maripaludis is a strictly anaerobic, methane-producing archaeon and facultative autotroph capable of biosynthesizing all the amino acids and vitamins required for growth. In this work, the novel 6-deoxy-5-ketofructose-1-phosphate (DKFP) pathway for the biosynthesis ...

Chemical Speciation and Bond Lengths of Organic Solutes by Core-Level Spectroscopy: pH and Solvent Influence on p-Aminobenzoic Acid.

PubMed

Stevens, Joanna S; Gainar, Adrian; Suljoti, Edlira; Xiao, Jie; Golnak, Ronny; Aziz, Emad F; Schroeder, Sven L M

2015-05-04

Through X-ray absorption and emission spectroscopies, the chemical, electronic and structural properties of organic species in solution can be observed. Near-edge X-ray absorption fine structure (NEXAFS) and resonant inelastic X-ray scattering (RIXS) measurements at the nitrogen K-edge of para-aminobenzoic acid reveal both pH- and solvent-dependent variations in the ionisation potential (IP), 1s→π* resonances and HOMO-LUMO gap. These changes unequivocally identify the chemical species (neutral, cationic or anionic) present in solution. It is shown how this incisive chemical state sensitivity is further enhanced by the possibility of quantitative bond length determination, based on the analysis of chemical shifts in IPs and σ* shape resonances in the NEXAFS spectra. This provides experimental access to detecting even minor variations in the molecular structure of solutes in solution, thereby providing an avenue to examining computational predictions of solute properties and solute-solvent interactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical Speciation and Bond Lengths of Organic Solutes by Core-Level Spectroscopy: pH and Solvent Influence on p -Aminobenzoic Acid

DOE PAGES

Stevens, Joanna S.; Gainar, Adrian; Suljoti, Edlira; ...

2015-03-18

Through X-ray absorption and emission spectroscopies, the chemical, electronic and structural properties of organic species in solution can be observed. Near-edge X-ray absorption fine structure (NEXAFS) and resonant inelastic X-ray scattering (RIXS) measurements at the nitrogen K-edge of para-aminobenzoic acid reveal both pH- and solvent-dependent variations in the ionisation potential (IP), 1s→π* resonances and HOMO–LUMO gap. These changes unequivocally identify the chemical species (neutral, cationic or anionic) present in solution. It is shown how this incisive chemical state sensitivity is further enhanced by the possibility of quantitative bond length determination, based on the analysis of chemical shifts in IPs andmore » σ* shape resonances in the NEXAFS spectra. Finally, this provides experimental access to detecting even minor variations in the molecular structure of solutes in solution, thereby providing an avenue to examining computational predictions of solute properties and solute–solvent interactions.« less

Amino Acid and Vitamin Requirements of Several Bacteroides Strains

PubMed Central

Quinto, Grace

1966-01-01

Nutritional studies were performed on nine Bacteroides strains, by use of the methodology and media of anaerobic rumen microbiology. Ristella perfoetens CCI required l-arginine hydrochloride, l-tryptophan, l-leucine, l-histidine hydrochloride, l-cysteine hydrochloride, dl-valine, dl-tyrosine, and the vitamin calcium-d-pantothenate, since scant turbidity developed in media without these nutrients. R. perfoetens was stimulated by glycine, dl-lysine hydrochloride, dl-isoleucine, l-proline, l-glutamic acid, dl-alanine, dl-phenylalanine, dl-methionine, and the vitamins nicotinamide and p-aminobenzoic acid, since maximal turbidity developed more slowly in media without these nutrients than in complete medium. Medium A-23, which was devised for R. perfoetens, contained salts, 0.0002% nicotinamide and calcium d-pantothenate, 0.00001% p-aminobenzoic acid, 0.044% l-tryptophan, 0.09% l-glutamic acid, and 0.1% of the other 13 amino acids listed above. Zuberella clostridiformis and seven strains of R. pseudoinsolita did not require vitamins, and showed no absolute requirement for any one amino acid. Various strains produced maximal turbidity more slowly in media deficient in l-proline, glycine, l-glutamic acid, dl-serine, l-histidine hydrochloride, dl-alanine, or l-cysteine hydrochloride, than in complete medium. These eight strains grew optimally in medium A-23 plus 0.1% dl-serine but without vitamins. PMID:16349673

4-Aminobiphenyl Downregulation of NAT2 Acetylator Genotype–Dependent N- and O-acetylation of Aromatic and Heterocyclic Amine Carcinogens in Primary Mammary Epithelial Cell Cultures from Rapid and Slow Acetylator Rats

PubMed Central

Jefferson, Felicia A.; Xiao, Gong H.; Hein, David W.

2009-01-01

Aromatic and heterocyclic amine carcinogens present in the diet and in cigarette smoke induce breast tumors in rats. N-acetyltransferase 1 (NAT1) and N-acetyltransferase 2 (NAT2) enzymes have important roles in their metabolic activation and deactivation. Human epidemiological studies suggest that genetic polymorphisms in NAT1 and/or NAT2 modify breast cancer risk in women exposed to these carcinogens. p-Aminobenzoic acid (selective for rat NAT2) and sulfamethazine (SMZ; selective for rat NAT1) N-acetyltransferase catalytic activities were both expressed in primary cultures of rat mammary epithelial cells. PABA, 2-aminofluorene, and 4-aminobiphenyl N-acetyltransferase and N-hydroxy-2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine and N-hydroxy-2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline O-acetyltransferase activities were two- to threefold higher in mammary epithelial cell cultures from rapid than slow acetylator rats. In contrast, SMZ (a rat NAT1-selective substrate) N-acetyltransferase activity did not differ between rapid and slow acetylators. Rat mammary cells cultured in the medium supplemented 24 h with 10μM ABP showed downregulation in the N-and O-acetylation of all substrates tested except for the NAT1-selective substrate SMZ. This downregulation was comparable in rapid and slow NAT2 acetylators. These studies clearly show NAT2 acetylator genotype–dependent N- and O-acetylation of aromatic and heterocyclic amine carcinogens in rat mammary epithelial cell cultures to be subject to downregulation by the arylamine carcinogen ABP. PMID:18842621

Rationalization of reduced penetration of drugs through ceramide gel phase membrane.

PubMed

Paloncýová, Markéta; DeVane, Russell H; Murch, Bruce P; Berka, Karel; Otyepka, Michal

2014-11-25

Since computing resources have advanced enough to allow routine molecular simulation studies of drug molecules interacting with biologically relevant membranes, a considerable amount of work has been carried out with fluid phospholipid systems. However, there is very little work in the literature on drug interactions with gel phase lipids. This poses a significant limitation for understanding permeation through the stratum corneum where the primary pathway is expected to be through a highly ordered lipid matrix. To address this point, we analyzed the interactions of p-aminobenzoic acid (PABA) and its ethyl (benzocaine) and butyl (butamben) esters with two membrane bilayers, which differ in their fluidity at ambient conditions. We considered a dioleoylphosphatidylcholine (DOPC) bilayer in a fluid state and a ceramide 2 (CER2, ceramide NS) bilayer in a gel phase. We carried out unbiased (100 ns long) and biased z-constraint molecular dynamics simulations and calculated the free energy profiles of all molecules along the bilayer normal. The free energy profiles converged significantly slower for the gel phase. While the compounds have comparable affinities for both membranes, they exhibit penetration barriers almost 3 times higher in the gel phase CER2 bilayer. This elevated barrier and slower diffusion in the CER2 bilayer, which are caused by the high ordering of CER2 lipid chains, explain the low permeability of the gel phase membranes. We also compared the free energy profiles from MD simulations with those obtained from COSMOmic. This method provided the same trends in behavior for the guest molecules in both bilayers; however, the penetration barriers calculated by COSMOmic did not differ between membranes. In conclusion, we show how membrane fluid properties affect the interaction of drug-like molecules with membranes.

Solvation and Aggregation of Meta-Aminobenzoic Acid in Water: Density Functional Theory and Molecular Dynamics Study

PubMed Central

Gaines, Etienne

2018-01-01

Meta-aminobenzoic acid, an important model system in the study of polymorphism and crystallization of active pharmaceutical ingredients, exist in water in both the nonionic (mABA) and zwitterionic (mABA±) forms. However, the constituent molecules of the polymorph that crystallizes from aqueous solutions are zwitterionic. This study reports atomistic simulations of the events surrounding the early stage of crystal nucleation of meta-aminobenzoic acid from aqueous solutions. Ab initio molecular dynamics was used to simulate the hydration of mABA± and mABA and to quantify the interaction of these molecules with the surrounding water molecules. Density functional theory calculations were conducted to determine the low-lying energy conformers of meta-aminobenzoic acid dimers and to compute the Gibbs free energies in water of nonionic, (mABA)2, zwitterionic, (mABA±)2, and nonionic-zwitterionic, (mABA)(mABA±), species. Classical molecular dynamics simulations of mixed mABA–mABA± aqueous solutions were carried out to examine the aggregation of meta-aminobenzoic acid. According to these simulations, the selective crystallization of the polymorphs whose constituent molecules are zwitterionic is driven by the formation of zwitterionic dimers in solution, which are thermodynamically more stable than (mABA)2 and (mABA)(mABA±) pairs. This work represents a paradigm of the role of molecular processes during the early stages of crystal nucleation in affecting polymorph selection during crystallization from solution. PMID:29360788

In Situ Dechlorination of Solvents in Saturated Soils

DTIC Science & Technology

1996-05-01

riboflavin 0.025 nicotinic acid 0.025 DL-calcium pantothenate 0.025 vitamin B12 0.025 p-aminobenzoic acid 0.025 lipoic acid 0.025 yeast extract...contaminated core materials collected from the Coast Guard Air Station in Traverse City, MI. Four fatty acids and three alcohols were tested for their...EXTRACT CONCENTRATIONS Vitamin/Yeast Extract Concentration (mg/L) d-biotin 0.01 folic acid 0.01 pyridoxine hydrochloride 0.05 thiamin hydrochloride 0.025

Rapid screening method to study the reactivity of UV filter substances towards skin proteins by high-performance thin-layer chromatography.

PubMed

Stiefel, C; Schwack, W

2013-12-01

Most UV filters used in sunscreens and other cosmetic products contain carbonyl groups, which generally are able to react with peptides or free amino acids of the human skin. To estimate their reactivity, we studied different prominent UV filter substances, octocrylene, ethylhexyl salicylate, 4-t-butyl-4'-methoxydibenzoylmethane, ethylhexyl methoxycinnamate, benzophenone-3, hydroxymethylbenzoyl sulphonic acid, octyldimethyl p-aminobenzoic acid, 3-benzylidene camphor, 4-methylbenzylidene camphor, diethylhexyl butamido triazone and ethylhexyl triazone. A simple screening method using an amino HPTLC plate as protein model was established. The influence of different reaction conditions like heating and irradiation was determined. The ketones BP-3, HMBS and BM-DBM revealed the highest binding rates after both irradiation and heating. After 1 h of irradiation, 82%, 28% and 96%, respectively, were bonded to the amino phase, while heating resulted in values of 52%, 36% and 16%. For BP-3 and HMBS, even storage in the dark at room temperature resulted in a low binding. Contrarily, for the two camphor derivatives 3-BC and 4-MBC, only irradiation led to a slightly turnover. UV filters with ester groups also showed a different behaviour depending on their main skeleton. While OCR especially reacted under heating with the amino phase, resulting in 36% of bound species after one hour, UV irradiation particularly encouraged a reaction of the other esters. After 1 h irradiation, 15% of EHMC, 38% of EHS and 48% of OD-PABA were bonded to the amino groups of the HPTLC plate, whereas the reactivity of the two triazones, EHT and DEBT, was comparatively low. Especially the UV filters BP-3, BM-DBM, HMBS, EHMC or OCR, which are commonly known to cause contact dermatitis, showed a high tendency to form adducts with the amino layer. Thus, the amino plate seems to be a proper tool to screen for skin sensitizers. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

In situ application of a cellulose bag and an ion exchanger for differentiation of labile and inert metal species in aquatic systems.

PubMed

Goveia, Danielle; Rosa, André Henrique; Bellin, Iramaia Corrêa; Lobo, Fabiana Aparecida; Fraceto, Leonardo Fernandes; Roveda, José Arnaldo Frutuoso; Romão, Luciane Pimenta Cruz; Dias Filho, Newton Luiz

2008-02-01

This work involved the development and application of a new analytical procedure for in-situ characterization of the lability of metal species in aquatic systems by using a system equipped with a diffusion membrane and cellulose organomodified with p-aminobenzoic acid groups (DM-Cell-PAB). To this end, the DM-Cell-PAB system was prepared by adding cellulose organomodified with p-aminobenzoic acid groups (Cell-PAB) to pre-purified cellulose bags. After the DM-Cell-PAB system was sealed, it was examined in the laboratory. The in-situ application involved immersing the DM-Cell-PAB system in two different rivers, enabling us to study the relative lability of metal species (Cu, Cd, Fe, Mn, and Ni) as a function of time and quantity of exchanger. The procedure is simple and opens up a new perspective for understanding environmental phenomena relating to the complexation, transport, stability, and lability of metal species in aquatic systems rich in organic matter.

UV Filters, Ingredients with a Recognized Anti-Inflammatory Effect

PubMed Central

Couteau, Céline; Chauvet, Catherine; Paparis, Eva; Coiffard, Laurence

2012-01-01

Background To explain observed differences during SPF determination using either an in vivo or in vitro method, we hypothesized on the presence of ingredients having anti-inflammatory properties. Methodology/Principal Findings To research our hypothesis, we studied the 21 UV filters both available on the market and authorized by European regulations and subjected these filters to the phorbol-myristate-acetate test using mice. We then catalogued the 13 filters demonstrating a significant anti-inflammatory effect with edema inhibition percentages of more than 70%. The filters are: diethylhexyl butamido triazone (92%), benzophenone-5 and titanium dioxide (90%), benzophenone-3 (83%), octocrylène and isoamyl p-methoxycinnamate (82%), PEG-25 PABA and homosalate (80%), octyl triazone and phenylbenzimidazole sulfonic acid (78%), octyl dimethyl PABA (75%), bis-ethylhexyloxyphenol methoxyphenyl triazine and diethylamino hydroxybenzoyl hexylbenzoate (70%). These filters were tested at various concentrations, including their maximum authorized dose. We detected a dose-response relationship. Conclusions/Significance The anti-inflammatory effect of a sunscreen ingredient may affect the in vivo SPF value. PMID:23284607

Metabolism and elimination of benzocaine by rainbow-trout, Oncorhynchus mykiss

USGS Publications Warehouse

Meinertz, J.R.; Gingerich, W.H.; Allen, J.L.

1991-01-01

1. Branchial and urinary elimination of benzocaine residues was evaluated in adult rainbow trout, oncorhynchus mykiss, given a single dorsal aortic dose of c-14-benzocaine hydrochloride.^2. Branchial elimination of benzocaine residues was rapid and accounted for 59.2% Of the dose during the first 3 h after dosing. Renal elimination of radioactivity was considerably slower; the kidney excreted 2.7% Dose within 3 h and 9.0% Within 24 h. Gallbladder bile contained 2.0% Dose 24 h after injection.^3. Of the radioactivity in radiochromatograms from water taken 3 min after injection, 87.3% Was benzocaine and 12.7% Was n-acetylated benzocaine. After 60 min, 32.7% Was benzocaine and 67.3% Was n-acetylated benzocaine.^4. Of the radioactivity in radiochromatograms from urine taken 1 h after dosing, 7.6% Was para-aminobenzoic acid, 59.7% Was n-acetylated para-aminobenzoic acid, 19.5% Was benzocaine, and 8.0% Was n-acetylated benzocaine. The proportion of the radioactivity in urine changed with time so that by 20 h, 1.0% Was para-aminobenzoic acid and 96.6% Was n-acetylated para-aminobenzoic acid.^5. Benzocaine and a more hydrophobic metabolite, n-acetylated benzocaine, were eliminated primarily through the gills; renal and biliary pathways were less significant elimination routes for benzocaine residues.

[Analysis of monosaccharides and uronic acids in polysaccharides by pre-column derivatization with p-aminobenzoic acid and high performance liquid chromatography].

PubMed

Hao, Guitang; Chen, Shangwei; Zhu, Song; Yin, Hongping; Dai, Jun; Cao, Yuhua

2007-01-01

An ion-pair reversed-phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous determination of carbohydrate and uronic acids was developed. p-Aminobenzoic acid (p-AMBA) was used for pre-column derivatization of the analytes, enabling fluorescence (lambda(ex) = 313 nm, lambda(em) = 358 nm) or ultraviolet (UV at 303 nm) detection. Reaction conditions such as reaction temperature and reaction time were optimized. Atlantis dC18 column with hydrophilic end capping was selected for the separation of derivatives. Effects of mobile phase compositions such as ion pairs and their concentrations and pH on the retention behaviors and separation results of 9 monosaccharides and 2 uronic acids were investigated. Derivatives of fructose, galactose, glucose, mannose, xylose, arabinose, ribose, galacturonic acid, fucose, glucuronic acid and rhamnose were separated within 42 min, applying tetrabutyl ammonium hydrogen bisulfate (TBAHSO4) as the ion pair reagent. The detection limits were between 3.38 x 10(-8) mol/L and 176 x 10(-8) mol/L for fluorescence detection and between 2.55 x 10(-7) mol/L and 13.4 x 10(-7) mol/L for UV detection. Good linearities were obtained with correlation coefficients (r2) above 0.99. The relative standard deviations (RSDs) of the peak area of the derivatives in 12 - 51 h after derivatization were from 2.5% to 3.9%. This method has been applied for the determination of mono-/disaccharides and uronic acids in spirulina polysaccharide after dissolved in trifluoroacetic acid solution (2 mol/L). The results showed this method is suitable for the analysis of monosaccharide compositions in polysaccharides.

Reversed-phase high-performance liquid chromatography of unsubstituted aminobenzoic acids

USGS Publications Warehouse

Abidi, S.L.

1989-01-01

High-performance liquid chromatographic (HPLC) characteristics of three position isomers of aminobenzoic acids (potential metabolites of important anesthetic drugs), were delineated with respect to their interactions with various mobile phases and stationary phases. HPLC with five hydrocarbonaceous phase, I?-cyclodextrin silica (CDS), macrophase MP-1 polymer (MP), macroporous polystyrene/divinylbenzene (MPD), octadecylsilica (ODS), and propylphenylsilica (PPS), yielded results explicable in terms of substituent effects derived from the bifunctional amino- and carboxy groups. For cases where mobile phases contained sulfonates or quaternary ammonium salts both having longer chain alkyls, retention of analytes on all but CDS appeared to proceed predominantly via an ion-pairing mechanism. The extent of the corresponding counter-ion effects decreased in the order: MPD > ODS > PPS > MP, while the analyte retention order paralleled thier pH2 values. On the other hand, an inverse relationship between the magnitude of capacity factors (k') and pK1 values of the title compounds was observed in experiments that produced retention data incompatible with ion-pair interaction rationales. The unique HPLC results obtained with the CDS phase are compared with those obtained with other phases.

NMR investigation of the influence of procaine and its metabolites on the water exchange through human erythrocyte membranes.

PubMed

Morariu, V V; Ionescu, M S; Frangopol, M; Grosescu, R; Lupu, M; Frangopol, P T

1987-06-12

The effect of procaine hydrochloride and its metabolites on the diffusional water exchange through erythrocyte membranes was investigated at 37 degrees C and at concentrations ranging between 5 X 10(-5) M and 5 X 10(-1) M by using the NMR manganese doping method. Procaine hydrochloride and 2-diethylaminoethanol have a moderate stimulating effect on the water exchange, of up to 20% at concentrations ranging between 10(-3) and 10(-2) M, while an increasing inhibitory effect was found at higher concentrations. The p-aminobenzoic acid has no effect on the water exchange up to 10(-2) M and, at higher concentrations, and apparent decreasing inhibition was noticed which is thought to be an artefact due to the uptake of Mn2+ by the cells. The temperature dependence studies suggest that procaine HCl enhances the uptake of Mn2+ by the cells. An opposite effect was found for rigid erythrocytes. The p-aminobenzoic acid and 2-diethylaminoethanol appeared to be more effective than procaine hydrochloride in increasing the uptake of Mn2+.

Chemical design of pH-sensitive nanovalves on the outer surface of mesoporous silicas for controlled storage and release of aromatic amino acid

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

Roik, N.V., E-mail: roik_nadya@ukr.net; Belyakova, L.A.

2014-07-01

Mesoporous silicas with hexagonally arranged pore channels were synthesized in water–ethanol-ammonia solution using cetyltrimethylammonium bromide as template. Directed modification of silica surface with N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups was realized by postsynthetic activation of halogenoalkylsilicas, which have surface uniformly or selectively distributed 3-chloropropyl groups, with 2-aminodiphenylamine in the liquid phase. Chemical composition of silica materials was estimated by IR spectroscopy and chemical analysis of the surface products of reactions. Characteristics of porous structure of MCM-41-type silicas were determined from X-ray and low-temperature nitrogen ad-desorption measurements. Release ability of synthesized silica carriers was established on encapsulation of 4-aminobenzoic acid in pore channels and subsequentmore » delivery at pH=6.86 and pH=1.00. It was found that N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups block pore entrances at neutral pH preventing 4-aminobenzoic acid release. At pH=1.00 repulsion of positively charged surface aromatic amino groups localized near pore orifices provides unhindered liberation of aromatic amino acid from mesoporous channels. - Graphical abstract: Blocking of pores with N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups at pH=6.86 for storage of ABA and opening of pore entrances at pH=1.00 for unhindered ABA liberation. - Highlights: • Modification of MCM-41 with N-[N′-(N′-phenyl)-2-aminophenyl]-3-aminopropyl groups. • Study of release ability of synthesized silica carriers in relation to amino acid. • Controlled blocking and opening of pores by amino groups at pH change were performed. • Retention of amino acid at pH=6.86 and its liberation at pH=1.00 was proved.« less

DFT calculations, spectroscopic, thermal analysis and biological activity of Sm(III) and Tb(III) complexes with 2-aminobenzoic and 2-amino-5-chloro-benzoic acids.

PubMed

Essawy, Amr A; Afifi, Manal A; Moustafa, H; El-Medani, S M

2014-10-15

The complexes of Sm(III) and Tb(III) with 2-aminobenzoic acid (anthranilic acid, AA) and 2-amino-5-chlorobenzoic acid (5-chloroanthranilic acid, AACl) were synthesized and characterized based on elemental analysis, IR and mass spectroscopy. The data are in accordance with 1:3 [Metal]:[Ligand] ratio. On the basis of the IR analysis, it was found that the metals were coordinated to bidentate anthranilic acid via the ionised oxygen of the carboxylate group and to the nitrogen of amino group. While in 5-chloroanthranilic acid, the metals were coordinated oxidatively to the bidentate carboxylate group without bonding to amino group; accordingly, a chlorine-affected coordination and reactivity-diversity was emphasized. Thermal analyses (TGA) and biological activity of the complexes were also investigated. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using SDDALL basis set. Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, dipole moment and orientation have been performed and discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

DFT calculations, spectroscopic, thermal analysis and biological activity of Sm(III) and Tb(III) complexes with 2-aminobenzoic and 2-amino-5-chloro-benzoic acids

NASA Astrophysics Data System (ADS)

Essawy, Amr A.; Afifi, Manal A.; Moustafa, H.; El-Medani, S. M.

2014-10-01

The complexes of Sm(III) and Tb(III) with 2-aminobenzoic acid (anthranilic acid, AA) and 2-amino-5-chlorobenzoic acid (5-chloroanthranilic acid, AACl) were synthesized and characterized based on elemental analysis, IR and mass spectroscopy. The data are in accordance with 1:3 [Metal]:[Ligand] ratio. On the basis of the IR analysis, it was found that the metals were coordinated to bidentate anthranilic acid via the ionised oxygen of the carboxylate group and to the nitrogen of amino group. While in 5-chloroanthranilic acid, the metals were coordinated oxidatively to the bidentate carboxylate group without bonding to amino group; accordingly, a chlorine-affected coordination and reactivity-diversity was emphasized. Thermal analyses (TGA) and biological activity of the complexes were also investigated. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using SDDALL basis set. Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, dipole moment and orientation have been performed and discussed.

Experimental (FT-IR, FT-Raman, 1H, 13C NMR) and theoretical study of alkali metal 2-aminobenzoates

NASA Astrophysics Data System (ADS)

Samsonowicz, M.; Świsłocka, R.; Regulska, E.; Lewandowski, W.

2008-09-01

The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-aminobenzoic acid was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR ( 1H and 13C) spectra for 2-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done on the basis of literature data, theoretical calculations and our previous experience. Characteristic shifts of bands and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons ( 1H NMR) and carbons ( 13C NMR) in the series of studied alkali metal 2-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G ∗∗ basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds.

Photophysics and Photochemistry of 2-Aminobenzoic Acid Anion in Aqueous Solution

NASA Astrophysics Data System (ADS)

Pozdnyakov, Ivan P.; Plyusnin, Victor F.; Grivin, Vjacheslav P.

2009-11-01

Nanosecond laser flash photolysis and absorption and fluorescence spectroscopy were used to study photochemical processes of 2-aminobenzoic acid anion (ABA-) in aqueous solutions. Excitation of this species gives rise to the ABA- triplet state to the ABA• radical and to the hydrated electron (eaq-). The last two species result from two-photon processes. In a neutral medium, the main decay channels of ABA- triplet state, the ABA• radical, and eaq- are T-T annihilation, recombination, and capture by the ABA- anion, respectively.

Mechanochemical synthesis of bumetanide-4-aminobenzoic acid molecular cocrystals: a facile and green approach to drug optimization.

PubMed

Bruni, Giovanna; Maietta, Mariarosa; Berbenni, Vittorio; Mustarelli, Piercarlo; Ferrara, Chiara; Freccero, Mauro; Grande, Vincenzo; Maggi, Lauretta; Milanese, Chiara; Girella, Alessandro; Marini, Amedeo

2014-08-07

Molecular cocrystals are of growing interest in pharmaceutics for their improved physicochemical properties. Their mechanochemical synthesis is very promising, being easy, cheap, and "green". Here, for the first time, we report on cocrystallization of bumetanide, a diuretic and natriuretic active principle, and 4-aminobenzoic acid. The synthesis is performed both by wet and dry grinding. The cocrystal formation was investigated with a wide range of techniques, including solid-state NMR, IR, XRD, microscopy, and thermal analysis. Wet and dry grinding procedures led to different cocrystal polymorphs. In particular, the dry method gave a cocrystal by powder amorphization and subsequent crystallization. DFT calculations at the B3LYP/6-31+G(d,p) level of theory shed light on the H-bond scheme at the basis of cocrystal formation. The cocrystals showed improved solubility and dissolution rate with respect to the drug alone. This could guarantee a faster absorption and a better bioavailability of the active principle.

Crystal and molecular structure of eight organic acid-base adducts from 2-methylquinoline and different acids

NASA Astrophysics Data System (ADS)

Zhang, Jing; Jin, Shouwen; Tao, Lin; Liu, Bin; Wang, Daqi

2014-08-01

Eight supramolecular complexes with 2-methylquinoline and acidic components as 4-aminobenzoic acid, 2-aminobenzoic acid, salicylic acid, 5-chlorosalicylic acid, 3,5-dinitrosalicylic acid, malic acid, sebacic acid, and 1,5-naphthalenedisulfonic acid were synthesized and characterized by X-ray crystallography, IR, mp, and elemental analysis. All of the complexes are organic salts except compound 2. All supramolecular architectures of 1-8 involve extensive classical hydrogen bonds as well as other noncovalent interactions. The results presented herein indicate that the strength and directionality of the classical hydrogen bonds (ionic or neutral) between acidic components and 2-methylquinoline are sufficient to bring about the formation of binary organic acid-base adducts. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, the complexes 1-8 displayed 2D-3D framework structure.

Investigation of Morphological and Functional Changes in the Small Intestine With Pancreatic Disease.

PubMed

Nakamura, Yosuke; Itoh, Akihiro; Kawashima, Hiroki; Ohno, Eizaburo; Itoh, Yuya; Hiramatsu, Takeshi; Sugimoto, Hiroyuki; Sumi, Hajime; Hayashi, Daijuro; Kuwahara, Takamichi; Funasaka, Kohei; Nakamura, Masanao; Miyahara, Ryoji; Ohmiya, Naoki; Katano, Yoshiaki; Ishigami, Masatoshi; Shimoyama, Yoshie; Nakamura, Shigeo; Goto, Hidemi; Hirooka, Yoshiki

2015-11-01

The aim of this study was to investigate the relationship between pancreas and small intestine evaluating the endoscopic and histopathologic findings of the proximal small intestine in pancreatic diseases. Fifty patients (18 patients with chronic pancreatitis, 17 patients with pancreatic cancer, 15 control subjects) underwent enteroscopy using a prototype enteroscope. The villous height of the jejunum on bioptic specimens was measured, and the mean values of the villi were compared among the 3 groups. Exocrine function was calculated by the pancreatic function diagnostic test, and the correlation between the recovery rate of p-aminobenzoic acid and the villous height was assessed. Finally, the distribution of the K cells secreting glucose-dependent insulinotropic polypeptide and the L cells secreting glucagon-like peptide 1 in the duodenum and jejunum was investigated using immunohistochemistry for glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1. The mean villous height in chronic pancreatitis (328 ± 67 μm) was significantly lower than that in pancreatic cancer (413 ± 57 μm) and control subjects (461 ± 97 μm) (P = 0.004 and P < 0.0001, respectively). A positive correlation was found between the recovery rate of p-aminobenzoic acid and the villous height (r = 0.52, P = 0.0001). The presence of K and L cells was verified in the duodenum and the jejunum. Close relationship between pancreas and small intestine was demonstrated.

An amperometric enzyme electrode and its biofuel cell based on a glucose oxidase-poly(3-anilineboronic acid)-Pd nanoparticles bionanocomposite for glucose biosensing.

PubMed

Sun, Lingen; Ma, Yixuan; Zhang, Pei; Chao, Long; Huang, Ting; Xie, Qingji; Chen, Chao; Yao, Shouzhuo

2015-06-01

A new amperometric enzyme electrode and its biofuel cell were fabricated based on a glucose oxidase (GOx)-poly(3-anilineboronic acid) (PABA)-Pd nanoparticles (PdNPs) bionanocomposite for biosensing of glucose. Briefly, Pd was electroplated on a multiwalled carbon nanotubes (MWCNTs)-modified Au electrode, and the GOx-PABA-PdNPs bionanocomposite was prepared on the Pd(plate)/MWCNTs/Au electrode through the chemical oxidation of a GOx-3-anilineboronic acid adduct by Na2PdCl4, followed by electrode-modification with an outer-layer chitosan (CS) film. The thus-prepared CS/GOx-PABA-PdNPs/Pd(plate)/MWCNTs/Au electrode exhibited a linear amperometric response to glucose concentration from 2.0 μM to 4.5 mM with a sensitivity of 160 μA/mM/cm(2), sub-μM detection limit, and excellent operation/storage stability in the first-generation biosensing mode, as well as excellent analytical performance in the second-generation biosensing mode. The good recoveries of glucose obtained from spiked urine samples revealed the application potential of our amperometric enzyme electrode. In addition, a glucose/O2 biofuel cell was constructed using this enzyme electrode as the anode and a Pt/MWCNTs/Au electrode as the cathode, and this biofuel cell as a self-powered biosensing device showed a linear voltage response to glucose concentration from 100 μM to 13.5 mM with a sensitivity of 43.5 mV/mM/cm(2) and excellent operation/storage stability. Copyright © 2015 Elsevier B.V. All rights reserved.

Photophysics and photochemistry of 2-aminobenzoic acid anion in aqueous solution.

PubMed

Pozdnyakov, Ivan P; Plyusnin, Victor F; Grivin, Vjacheslav P

2009-12-24

Nanosecond laser flash photolysis and absorption and fluorescence spectroscopy were used to study photochemical processes of 2-aminobenzoic acid anion (ABA(-)) in aqueous solutions. Excitation of this species gives rise to the ABA(-) triplet state to the ABA* radical and to the hydrated electron (e(aq)(-)). The last two species result from two-photon processes. In a neutral medium, the main decay channels of ABA(-) triplet state, the ABA* radical, and e(aq)(-) are T-T annihilation, recombination, and capture by the ABA(-) anion, respectively.

The use of the 2-aminobenzoic acid tag for oligosaccharide gel electrophoresis.

PubMed

Huang, Z; Prickett, T; Potts, M; Helm, R F

2000-08-18

Gel electrophoresis of fluorophore labeled saccharides provides a rapid and reliable method to screen enzymatic and/or chemical treatments of polysaccharides and glycoconjugates, as well as a sensitive and efficient microscale method to separate and purify oligosaccharides for further analysis. A simple and inexpensive method of derivatization and analysis using 2-aminobenzoic acid (anthranilic acid, AA) is described and applied to the extracellular polysaccharide released by the desiccation tolerant cyanobacterium Nostoc commune DRH-1. The results of these analyses suggest a possible protective functionality of two pendent groups, as well as a potential relationship between these groups and the desiccation tolerance of the organism.

Hyaluronic acid based hydroxamate and conjugates with biologically active amines: In vitro effect on matrix metalloproteinase-2.

PubMed

Ponedel'kina, Irina Yu; Gaskarova, Aigul R; Khaybrakhmanova, Elvira A; Lukina, Elena S; Odinokov, Victor N

2016-06-25

In this study, water soluble hyaluronic acid (HA) based hydroxamate and conjugates with biologically active amines and hydrazides such as p- and o-aminophenols, anthranilic, 4- and 5-aminosalicylic acids, nicotinic, N-benzylnicotinic and isonicotinic hydrazides, p-aminobenzenesulfonamide (Streptocide), p-aminobenzoic acid diethylaminoethyl ester (Procaine), and 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (4-aminoantipyrene) were examined as matrix metalloproteinase-2 inhibitors (MMPIs). In a dose of 0.27-270μM, the most efficient MMPIs were HA conjugates with o-aminophenol=4-aminoantipyrine>4-aminosalicylic acid>5-aminosalicylic acid. Conjugates with Streptocide, Procaine and HA hydroxamate showed 40-50% inhibitory effect at all used concentrations. Conjugates with anthranilic acid and isonicotinic hydrazide (Isoniazid) in a dose of 0.27μM inhibited enzyme activity by ∼70%, but with the concentration increase their inhibitory effect was decreased. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Facile Semi-Synthetic Approach towards Halogen-Substituted Aminobenzoic Acid Analogues of Platensimycin.

PubMed

Qiu, Lin; Tian, Kai; Pan, Jian; Jiang, Lin; Yang, Hu; Zhu, Xiangcheng; Shen, Ben; Duan, Yanwen; Huang, Yong

2017-02-09

Platensimycin (PTM), produced by several strains of Streptomyces platensis, is a promising drug lead for infectious diseases and diabetes. The recent pilot-scale production of PTM from S. platensis SB12026 has set the stage for the facile semi-synthesis of a focused library of PTM analogues. In this study, gram-quantity of platensic acid (PTMA) was prepared by the sulfuric acid-catalyzed ethanolysis of PTM, followed by a mild hydrolysis in aqueous lithium hydroxide. Three PTMA esters were also obtained in near quantitative yields in a single step, suggesting a facile route to make PTMA aliphatic esters. 1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate (HATU)-catalyzed coupling of PTMA and 33 aminobenzoates resulted in the synthesis of 28 substituted aminobenzoate analogues of PTM, among which 26 of them were reported for the first time. Several of the PTM analogues showed weak antibacterial activity against methicillin-resistant Staphylococcus aureus. Our study supported the potential utility to integrate natural product biosynthetic and semi-synthetic approaches for structure diversification.

2-Aminobenzamide and 2-Aminobenzoic Acid as New MALDI Matrices Inducing Radical Mediated In-Source Decay of Peptides and Proteins

NASA Astrophysics Data System (ADS)

Smargiasso, Nicolas; Quinton, Loic; de Pauw, Edwin

2012-03-01

One of the mechanisms leading to MALDI in-source decay (MALDI ISD) is the transfer of hydrogen radicals to analytes upon laser irradiation. Analytes such as peptides or proteins may undergo ISD and this method can therefore be exploited for top-down sequencing. When performed on peptides, radical-induced ISD results in production of c- and z-ions, as also found in ETD and ECD activation. Here, we describe two new compounds which, when used as MALDI matrices, are able to efficiently induce ISD of peptides and proteins: 2-aminobenzamide and 2-aminobenzoic acid. In-source reduction of the disulfide bridge containing peptide Calcitonin further confirmed the radicalar mechanism of the ISD process. ISD of peptides led, in addition to c- and z-ions, to the generation of a-, x-, and y-ions both in positive and in negative ion modes. Finally, good sequence coverage was obtained for the sequencing of myoglobin (17 kDa protein), confirming the effectiveness of both 2-aminobenzamide and 2-aminobenzoic acid as MALDI ISD matrices.

2-Aminobenzamide and 2-aminobenzoic acid as new MALDI matrices inducing radical mediated in-source decay of peptides and proteins.

PubMed

Smargiasso, Nicolas; Quinton, Loic; De Pauw, Edwin

2012-03-01

One of the mechanisms leading to MALDI in-source decay (MALDI ISD) is the transfer of hydrogen radicals to analytes upon laser irradiation. Analytes such as peptides or proteins may undergo ISD and this method can therefore be exploited for top-down sequencing. When performed on peptides, radical-induced ISD results in production of c- and z-ions, as also found in ETD and ECD activation. Here, we describe two new compounds which, when used as MALDI matrices, are able to efficiently induce ISD of peptides and proteins: 2-aminobenzamide and 2-aminobenzoic acid. In-source reduction of the disulfide bridge containing peptide Calcitonin further confirmed the radicalar mechanism of the ISD process. ISD of peptides led, in addition to c- and z-ions, to the generation of a-, x-, and y-ions both in positive and in negative ion modes. Finally, good sequence coverage was obtained for the sequencing of myoglobin (17 kDa protein), confirming the effectiveness of both 2-aminobenzamide and 2-aminobenzoic acid as MALDI ISD matrices.

Structural and functional effects of nucleotide variation on the human TB drug metabolizing enzyme arylamine N-acetyltransferase 1.

PubMed

Cloete, Ruben; Akurugu, Wisdom A; Werely, Cedric J; van Helden, Paul D; Christoffels, Alan

2017-08-01

The human arylamine N-acetyltransferase 1 (NAT1) enzyme plays a vital role in determining the duration of action of amine-containing drugs such as para-aminobenzoic acid (PABA) by influencing the balance between detoxification and metabolic activation of these drugs. Recently, four novel single nucleotide polymorphisms (SNPs) were identified within a South African mixed ancestry population. Modeling the effects of these SNPs within the structural protein was done to assess possible structure and function changes in the enzyme. The use of molecular dynamics simulations and stability predictions indicated less thermodynamically stable protein structures containing E264K and V231G, while the N245I change showed a stabilizing effect. Coincidently the N245I change displayed a similar free energy landscape profile to the known R64W amino acid substitution (slow acetylator), while the R242M displayed a similar profile to the published variant, I263V (proposed fast acetylator), and the wild type protein structure. Similarly, principal component analysis indicated that two amino acid substitutions (E264K and V231G) occupied less conformational clusters of folded states as compared to the WT and were found to be destabilizing (may affect protein function). However, two of the four novel SNPs that result in amino acid changes: (V231G and N245I) were predicted by both SIFT and POLYPHEN-2 algorithms to affect NAT1 protein function, while two other SNPs that result in R242M and E264K substitutions showed contradictory results based on SIFT and POLYPHEN-2 analysis. In conclusion, the structural methods were able to verify that two non-synonymous substitutions (E264K and V231G) can destabilize the protein structure, and are in agreement with mCSM predictions, and should therefore be experimentally tested for NAT1 activity. These findings could inform a strategy of incorporating genotypic data (i.e., functional SNP alleles) with phenotypic information (slow or fast acetylator) to better prescribe effective treatment using drugs metabolized by NAT1. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

A comparative study of monosaccharide composition analysis as a carbohydrate test for biopharmaceuticals.

PubMed

Harazono, Akira; Kobayashi, Tetsu; Kawasaki, Nana; Itoh, Satsuki; Tada, Minoru; Hashii, Noritaka; Ishii, Akiko; Arato, Teruyo; Yanagihara, Shigehiro; Yagi, Yuki; Koga, Akiko; Tsuda, Yuriko; Kimura, Mikiko; Sakita, Masashi; Kitamura, Satoshi; Yamaguchi, Hideto; Mimura, Hisashi; Murata, Yoshimi; Hamazume, Yasuki; Sato, Takayuki; Natsuka, Shunji; Kakehi, Kazuaki; Kinoshita, Mitsuhiro; Watanabe, Sakie; Yamaguchi, Teruhide

2011-05-01

The various monosaccharide composition analysis methods were evaluated as monosaccharide test for glycoprotein-based pharmaceuticals. Neutral and amino sugars were released by hydrolysis with 4-7N trifluoroacetic acid. The monosaccharides were N-acetylated if necessary, and analyzed by high-performance liquid chromatography (HPLC) with fluorometric or UV detection after derivatization with 2-aminopyridine, ethyl 4-aminobenzoate, 2-aminobenzoic acid or 1-phenyl-3-methyl-5-pyrazolone, or high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Sialic acids were released by mild acid hydrolysis or sialidase digestion, and analyzed by HPLC with fluorometric detection after derivatization with 1,2-diamino-4,5-methylenedioxybenzene, or HPAEC-PAD. These methods were verified for resolution, linearity, repeatability, and accuracy using a monosaccharide standard solution, a mixture of epoetin alfa and beta, and alteplase as models. It was confirmed that those methods were useful for ensuring the consistency of glycosylation. It is considered essential that the analytical conditions including desalting, selection of internal standards, release of monosaccharides, and gradient time course should be determined carefully to eliminate interference of sample matrix. Various HPLC-based monosaccharide analysis methods were evaluated as a carbohydrate test for glycoprotein pharmaceuticals by an inter-laboratory study. Copyright © 2011 The International Association for Biologicals. Published by Elsevier Ltd. All rights reserved.

STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS

PubMed Central

Landsteiner, K.; Di Somma, A. A.

1940-01-01

Sensitization of guinea pigs to picric acid was obtained by application of oil solutions to the skin, preferably on inflamed sites or by treatment with a compound of picric acid with n-butyl-p-aminobenzoate. The lesions obtained in sensitive animals on superficial administration bore resemblance to human eczema. It seems probable that picric acid sensitization is an instance where a substance does not sensitize directly but after conversion into a more reactive compound, a principle which should be of wider application to instances where the original substance does not readily form conjugates. PMID:19871030

Calcium phenylphosphonate as a host for 4-aminobenzoic acid-Synthesis, characterization, and cation adsorption from ethanol solution

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

Lazarin, Angelica M., E-mail: amlazarin2@uem.br; Ganzerli, Thiago A.; Sernaglia, Rosana L.

2009-11-15

Crystalline lamellar calcium phenylphosphonate retained 4-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1160-695 cm{sup -1} interval confirmed the presence of the phosphonate groups attached to the inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 1532 and 1751 pm for the original and the intercalated compounds, respectively. The thermogravimetric curves of both layered compounds showed the release of water molecules and the organic moiety in distinct stages, to yield a final Ca(PO{sub 3}){sub 2} residue. Solid-state {sup 31}P nuclear magnetic resonance spectra presented only one peak formore » the phenylphosphonate groups attached to the main inorganic polymeric structure near 12.4 ppm. The adsorption isotherms from ethanol gave the maximum adsorption capacities of 1.68 and 0.50 mmol g{sup -1} for copper and cobalt, respectively, whose average stability constants followed Co > Cu; the number of ligands was determined as four for both cations.« less

Anthranilate synthase subunit organization in Chromobacterium violaceum.

PubMed

Carminatti, C A; Oliveira, I L; Recouvreux, D O S; Antônio, R V; Porto, L M

2008-09-16

Tryptophan is an aromatic amino acid used for protein synthesis and cellular growth. Chromobacterium violaceum ATCC 12472 uses two tryptophan molecules to synthesize violacein, a secondary metabolite of pharmacological interest. The genome analysis of this bacterium revealed that the genes trpA-F and pabA-B encode the enzymes of the tryptophan pathway in which the first reaction is the conversion of chorismate to anthranilate by anthranilate synthase (AS), an enzyme complex. In the present study, the organization and structure of AS protein subunits from C. violaceum were analyzed using bioinformatics tools available on the Web. We showed by calculating molecular masses that AS in C. violaceum is composed of alpha (TrpE) and beta (PabA) subunits. This is in agreement with values determined experimentally. Catalytic and regulatory sites of the AS subunits were identified. The TrpE and PabA subunits contribute to the catalytic site while the TrpE subunit is involved in the allosteric site. Protein models for the TrpE and PabA subunits were built by restraint-based homology modeling using AS enzyme, chains A and B, from Salmonella typhimurium (PDB ID 1I1Q).

The magnetorheological fluid of carbonyl iron suspension blended with grafted MWCNT or graphene

NASA Astrophysics Data System (ADS)

Rwei, Syang-Peng; Ranganathan, Palraj; Chiang, Whe-Yi; Wang, Tza-Yi

2017-12-01

In this work, the magnetorheological (MR) fluids containing MWCNT/CI (carbonyl iron) complex and graphene/CI complex were prepared and have the better dispersity in silicone oil than CI powders alone. 1, 4-Aminobenzoic acid (PABA) was used as a grafting agent to modify CI powders to have NH2-end-group so that such nanoparticles can adsorb to acid-treated MWCNT or graphene via attraction of NH2 and COOH groups. The MWCNT/CI complex and graphene/CI complex have a structure of carbonyl iron nanoparticles adsorbed to MWCNT and graphene by self assembly, respectively. Because the carbonyl iron particles possessing magnetic permeability in nanometer scale adsorb to MWCNT or graphene which usually has a nanometer-scaled diameter and a micrometer-scaled length in this work, the dispersity of MWCNT/CI or graphene/CI complex in silicone oil is superior than the previous report [15] that the micrometer-scaled carbonyl iron microspheres were coated with multiwalled carbon nanotubes. Among CI (unmodified), MWCNT/CI and graphene/CI, graphene/CI has the best dispersity while MWCNT/CI still has the better dispersity than unmodified CI. At the temperature T = 300 K, the saturation magnetizations of CI, MWCNT/CI, graphene/CI are 208, 211 emu/g, and 204 emu/g, respectively, indicating that MWCNT/CI complex and graphene/CI complex still maintain the saturation magnetization as high as CI without being interfered by the blended MWCNT or graphene. A wide dynamic range of the yield stress adjusted through varying the electric current can be achieved by the MR fluids containing 69 wt% MWCNT/CI and graphene/CI which is useful in a shock absorber or damper. The result of the yield stress indicates the suspended MWCNT/CI particles are oriented more easily toward the direction perpendicular to the flow direction to block the flow stream lines.

Characterization and purification of polyphenol oxidase from artichoke (Cynara scolymus L.).

PubMed

Dogan, Serap; Turan, Yusuf; Ertürk, Hatibe; Arslan, Oktay

2005-02-09

In this study, the polyphenol oxidase (PPO) of artichoke (Cynara scolymus L.) was first purified by a combination of (NH(4))(2)SO(4) precipitation, dialysis, and a Sepharose 4B-L-tyrosine-p-aminobenzoic acid affinity column. At the end of purification, 43-fold purification was achieved. The purified enzyme migrated as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Polyacrylamide gel electrophoresis indicated that PPO had a 57 kDa molecular mass. Second, the contents of total phenolic and protein of artichoke head extracts were determined. The total phenolic content of artichoke head was determined spectrophotometrically according to the Folin-Ciocalteu procedure and was found to be 425 mg 100 g(-1) on a fresh weight basis. Protein content was determined according to Bradford method. Third, the effects of substrate specificity, pH, temperature, and heat inactivation were investigated on the activity of PPO purified from artichoke. The enzyme showed activity to 4-methylcatechol, pyrogallol, catechol, and L-dopa. No activity was detected toward L-tyrosine, resorsinol, and p-cresol. According to V(max)/K(m) values, 4-methylcatechol (1393 EU min(-1) mM(-1)) was the best substrate, followed by pyrogallol (1220 EU min(-1) mM(-1)), catechol (697 EU min(-1) mM(-1)), and L-dopa (102 EU min(-1) mM(-1)). The optimum pH values for PPO were 5.0, 8.0, and 7.0 using 4-methylcatechol, pyrogallol, and catechol as substrate, respectively. It was found that optimum temperatures were dependent on the substrates studied. The enzyme activity decreased due to heat denaturation of the enzyme with increasing temperature and inactivation time for 4-methylcatechol and pyrogallol substrates. However, all inactivation experiments for catechol showed that the activity of artichoke PPO increased with mild heating, reached a maximum, and then decreased with time. Finally, inhibition of artichoke PPO was investigated with inhibitors such as L-cysteine, EDTA, ascorbic acid, gallic acid, d,L-dithiothreitol, tropolone, glutathione, sodium azide, benzoic acid, salicylic acid, and 4-aminobenzoic acid using 4-methylcatechol, pyrogallol, and catechol as substrate. The presence of EDTA, 4-aminobenzoic acid, salicylic acid, gallic acid, and benzoic acid did not cause the inhibition of artichoke PPO. A competitive-type inhibition was obtained with sodium azide, L-cysteine, and d,L-dithiothreitol inhibitors using 4-methylcatechol as substrate; with L-cysteine, tropolone, d,L-dithiothreitol, ascorbic acid, and sodium azide inhibitors using pyrogallol as substrate; and with L-cysteine, tropolone, d,L-dithiotreitol, and ascorbic acid inhibitors using catechol as a substrate. A mixed-type inhibition was obtained with glutathione inhibitor using 4-methylcatechol as a substrate. A noncompetitive inhibition was obtained with tropolone and ascorbic acid inhibitors using 4-methylcatechol as substrate, with glutathione inhibitor using pyrogallol as substrate, and with glutathione and sodium azide inhibitors using catechol as substrate. From these results, it can be said that the most effective inhibitor for artichoke PPO is tropolone. Furthermore, it was found that the type of inhibition depended on the origin of the PPO studied and also on the substrate used.

Mutant Enrichment in the Colonial Alga, EUDORINA ELEGANS

PubMed Central

Toby, A. L.; Kemp, C. L.

1975-01-01

An enrichment procedure has been developed that results in at least a 200x increase in mutation frequency in the colonial alga, Eudorina elegans. A period of nitrogen starvation followed by treatment with 8-azaguanine results in the death of wild-type cells and the maintenance of mutants. N'-nitro-N-nitro-soguanidine-induced acetate, p-aminobenzoic acid and reduced nitrogen requiring mutants have been isolated by this procedure. PMID:1205128

Versatile peroxidase of Bjerkandera fumosa: substrate and inhibitor specificity.

PubMed

Pozdnyakova, Natalia; Makarov, Oleg; Chernyshova, Marina; Turkovskaya, Olga; Jarosz-Wilkolazka, Anna

2013-01-10

The inhibitor and substrate specificities of versatile peroxidase from Bjerkandera fumosa (VPBF) were studied. Two different effects were found: NaN(3), Tween-80, anthracene, and fluorene decreased the activity of VPBF, but p-aminobenzoic acid increased it. A mixed mechanism of effector influence on the activity of this enzyme was shown. The catalytic properties of VPBF in the oxidation of mono- and polycyclic aromatic compounds were studied also. 2,7-Diaminofluorene, ABTS, veratryl alcohol, and syringaldazine can be oxidized by VPBF in two ways: either directly by the enzyme or by diffusible chelated Mn(3+) as an oxidizing agent. During VPBF oxidation of 2,7-diaminofluorene, both with and without Mn(2+), biphasic kinetics with apparent saturation in both micromolar and millimolar ranges were obtained. In the case of ABTS, inhibition of VPBF activity by an excess of substrate was observed. Direct oxidation of p-aminobenzoic acid by versatile peroxidase was found for the first time. The oxidation of three- and four-ring PAHs by VPBF was investigated, and the oxidation of anthracene, phenanthrene, fluorene, pyrene, chrysene, and fluoranthene was shown. The products of PAH oxidation (9,10-anthraquinone, 9,10-phenanthrenequinone, and 9-fluorenone) catalyzed by VPBF were identified. Copyright © 2012 Elsevier Inc. All rights reserved.

The Role of Pancreatic Enzyme Replacement Therapy in Unresectable Pancreatic Cancer: A Prospective Cohort Study.

PubMed

Saito, Tomotaka; Hirano, Kenji; Isayama, Hiroyuki; Nakai, Yousuke; Saito, Kei; Umefune, Gyotane; Akiyama, Dai; Watanabe, Takeo; Takagi, Kaoru; Hamada, Tsuyoshi; Takahara, Naminatsu; Uchino, Rie; Mizuno, Suguru; Kogure, Hirofumi; Matsubara, Saburo; Yamamoto, Natsuyo; Tada, Minoru; Koike, Kazuhiko

2017-03-01

Although patients with pancreatic cancer (PC) are prone to exocrine pancreatic insufficiency, there are little evidence about pancreatic enzyme replacement therapy (PERT) in patients with PC, especially those receiving chemotherapy. This is a prospective consecutive observational study of PERT in patients with unresectable PC. We prospectively enrolled patients receiving chemotherapy for unresectable PC from April 2012 to February 2014 and prescribed oral pancrelipase of 48,000 lipase units per meal (pancrelipase group). N-benzoyl-tryrosyl para-aminobenzoic acid test was performed at baseline. Patients receiving chemotherapy before April 2012 were retrospectively studied as a historical cohort. Data on the nutritional markers at baseline and 16 weeks were extracted, and serial changes, defined as the ratio of markers at 16 weeks/baseline, were compared between 2 groups. A total of 91 patients (46 in the pancrelipase group and 45 in the historical cohort) were analyzed. N-benzoyl-tryrosyl para-aminobenzoic acid test was low in 94% of the pancrelipase group. Serial change in the pancrelipase group versus historical cohort was 1.01 versus 0.95 in body mass index (P < 0.001) and 1.03 versus 0.97 in serum albumin (P = 0.131). The rate of exocrine pancreatic insufficiency in unresectable PC was high, and PERT can potentially improve the nutritional status during chemotherapy.

Ethnicity is important for creatinine excretion among Inuit and Caucasians in Greenland.

PubMed

Andersen, Stig; Dehnfeld, Marie; Laurberg, Peter

2015-01-01

Human nutrition, contamination and renal function are commonly assessed by the analysis of urine. A complete 24-hour urine sample is the ideal but it is inconvenient and unreliable. Thus, spot urine sampling with creatinine adjustment is widely used. Stratification for age and gender is recommended. Still, ethnicity may influence creatinine excretion. We collected 104 24-h urine samples among Inuit and non-Inuit living in Greenland. Completeness of sampling was checked by using para-amino benzoic acid (PABA) that also allowed for compensation of creatinine excretion when sampling was incomplete. We measured creatinine using the Jaffe method and PABA by the HPLC method. Participants were recruited from the capital city, a major town and a settlement (n = 36/48/20). They were aged 30-69 years with 78 Inuit and 26 non-Inuit. Inuit were smaller than non-Inuit (Caucasians): height, 163 vs. 177 cm, p < 0.001; weight, 71 vs. 84 kg, p = 0.001 with similar BMI. Creatinine excretion was lower in Inuit compared to non-Inuit (men, 1344/1807 mg/24 h; women 894/1259 mg/24 h; p = 0.002; 0.02). It was influenced by age (p < 0.001), gender (p < 0.001), weight (p = 0.001) and ethnicity (p = 0.030) while not by the intake of the protein-rich Inuit diet in the adjusted analysis. Creatinine excretion was described by: Inuit men, 1925 mg - (13.1 × age); Inuit women, 1701 mg - (17.0 × age). Inuit and Caucasians have different creatinine excretion. It is recommended to stratify by ethnicity in addition to adjustment for age and gender when using creatinine correction of spot urine samples.

Detection of chitinase activity by 2-aminobenzoic acid labeling of chito-oligosaccharides.

PubMed

Ghauharali-van der Vlugt, Karen; Bussink, Anton P; Groener, Johanna E M; Boot, Rolf G; Aerts, Johannes M F G

2009-01-01

Chitinases are hydrolases capable of hydrolyzing the abundant natural polysaccharide chitin. Next to artificial fluorescent substrates, more physiological chito-oligomers are commonly used in chitinase assays. Analysis of chito-oligosaccharides products is generally accomplished by UV detection. However, the relatively poor sensitivity poses a serious limitation. Here we report on a novel, much more sensitive assay for the detection of chito-oligosaccharide reaction products released by chitinases, based on fluorescent detection, following chemical labeling by 2-aminobenzoic acid. Comparison with existing UV-based assays, shows that the novel assay offers the same advantages yet allows detection of chito-oligosaccharides in the low picomolar range.

Comparison of inhibition effects of some benzoic acid derivatives on sheep heart carbonic anhydrase

NASA Astrophysics Data System (ADS)

Kiliç, Deryanur; Yildiz, Melike; Şentürk, Murat; Erdoǧan, Orhan; Küfrevioǧlu, Ömer Irfan

2016-04-01

Carbonic anhydrase (CA) is a family of metalloenzymes that requires Zn as a cofactor and catalyze the quick conversion of CO2 to HCO3- and H+. Inhibitors of the carbonic anhydrases (CAs) have medical usage of significant diseases such as glaucoma, epilepsy, gastroduodenal ulcers, acid-base disequilibria and neurological disorders. In the present study, inhibition of CA with some benzoic derivatives (1-6) were investigated. Sheep heart CA (shCA) enzyme was isolated by means of designed affinity chromatography gel (cellulose-benzyl-sulfanylamide) 42.45-fold in a yield of 44 % with 564.65 EU/mg. Purified shCA enzyme was used in vitro studies. In the studies, IC50 values were calculated for 3-aminobenzoic acid (1), 4-aminobenzoic acid (2), 2-hydroxybenzoic acid (3), 2-benzoylbenzoic acid (4), 2,3-dimethoxybenzoic acid (5), and 3,4,5-trimethoxybenzoic acid (6), showing the inhibition effects on the purified enzyme. Such molecules can be used as pioneer for discovery of novel effective CA inhibitors for medicinal chemistry applications.

Portable electrochemical sensor based on 4-aminobenzoic acid-functionalized herringbone carbon nanotubes for the determination of ascorbic acid and uric acid in human fluids.

PubMed

Abellán-Llobregat, A; González-Gaitán, C; Vidal, L; Canals, A; Morallón, E

2018-06-30

A new portable electrochemical sensor based on 4-aminobenzoic acid-modified herringbone carbon nanotubes (hCNTs-4ABA/Au-IDA) has been developed for the simultaneous determination of ascorbic acid (AA) and uric acid (UA) in physiological fluids. AA and UA were quantified by chronoamperometry at 0.1 and 0.32 V, respectively, in phosphate buffer solution (PBS 0.25 M, pH 7.0). Significant results were obtained for the separate quantification of AA and UA, with a limit of detection (LOD) of 0.65 μM for both analytes, and sensitivities of (9.0 ± 0.4) A g -1 mM -1 and (8.8 ± 0.3) A g -1 mM -1 for AA and UA, respectively. Repeatability was studied at 50 μM for AA and UA, providing relative standard deviations (RSD) lower than 9%. Additions of glucose, dopamine and epinephrine did not interfere with the AA and UA determination. Furthermore, UA did not interfere with AA determination at 0.1 V, although AA additions increased the current recorded at 0.32 V. The method has been successfully applied to human urine, perspiration and serum samples, without significant matrix effects, which allows for the use of an external calibration and the analysis of all the matrices investigated. Copyright © 2018 Elsevier B.V. All rights reserved.

Antibiotics in the chemical communication of fungi.

PubMed

Kettering, Melanie; Sterner, Olov; Anke, Timm

2004-01-01

In dual cultures Oudemansiella mucida and Xerula melanotricha (basidiomycetes) react to the presence of living Penicillium notatum or P. turbatum with an increased production of strobilurin A (1) or X (2). P. notatum in turn reacts to the two basidiomycetes or their antibiotic strobilurin A alone with the production of N-(2-hydroxypropanoyl)-2-aminobenzoic acid amide (3) or chrysogine (4). P. melinii and P. urticae overgrow O. mucida due to complete resistance to strobilurin A. P. brevicompactum, P. citrinum, P. janczewskii and the other Penicillium strains are all sensitive but apparently do not induce O. mucida to produce the amounts of strobilurin A needed to inhibit their growth.

Linkage and Branch Analysis of High-Mannose Oligosaccharides Using Closed-Ring Labeling of 8-Aminopyrene-1,3,6-Trisulfonate and P-Aminobenzoic Ethyl Ester and Negative Ion Trap Mass Spectrometry

NASA Astrophysics Data System (ADS)

Chen, Shu-Ting; Her, Guor-Rong

2012-08-01

A strategy based on negative ion electrospray ionization tandem mass spectrometry and closed-ring labeling with both 8-aminopyrene-1,3,6-trisulfonate (APTS) and p-aminobenzoic acid ethyl ester (ABEE) was developed for linkage and branch determination of high-mannose oligosaccharides. X-type cross-ring fragment ions obtained from APTS-labeled oligosaccharides by charge remote fragmentation provided information on linkages near the non-reducing terminus. In contrast, A-type cross-ring fragment ions observed from ABEE-labeled oligosaccharides yielded information on linkages near the reducing terminus. This complementary information provided by APTS- and ABEE-labeled oligosaccharides was utilized to delineate the structures of the high-mannose oligosaccharides. As a demonstration of this approach, the linkages and branches of high-mannose oligosaccharides Man5GlcNAc2, Man6GlcNAc2, Man8GlcNAc2, and Man9GlcNAc2 cleaved from the ribonuclease B were assigned from MS2 spectra of ABEE- and APTS-labeled derivatives.

Dual fluorescence of N-phenylanthranilic acid: Effect of solvents, pH and beta-cyclodextrin.

PubMed

Rajendiran, N; Balasubramanian, T

2007-11-01

Spectral characteristics of N-phenylanthranilic acid (NPAA) have been studied in different solvents, pH and beta-cyclodextrin (beta-CD) and compared with anthranilic acid (2-aminobenzoic acid, 2ABA). In all solvents a dual fluorescence is observed in NPAA, whereas 2ABA gives single emission. Combining the results observed in the absorption, fluorescence emission and fluorescence excitation spectra, it is found that strong intramolecular hydrogen bonding (IHB) interactions present in NPAA molecule. The inclusion complex of NPAA with beta-CD is analysed by UV-vis, fluorimetry, FT-IR, (1)H NMR, scanning electron microscope and AM 1 method. The above spectral studies show that NPAA forms a 1:1 inclusion complex with beta-CD and COOH group present in the beta-CD cavity. A mechanism is proposed to explain the inclusion process.

Dual fluorescence of N-phenylanthranilic acid: Effect of solvents, pH and β-cyclodextrin

NASA Astrophysics Data System (ADS)

Rajendiran, N.; Balasubramanian, T.

2007-11-01

Spectral characteristics of N-phenylanthranilic acid (NPAA) have been studied in different solvents, pH and β-cyclodextrin (β-CD) and compared with anthranilic acid (2-aminobenzoic acid, 2ABA). In all solvents a dual fluorescence is observed in NPAA, whereas 2ABA gives single emission. Combining the results observed in the absorption, fluorescence emission and fluorescence excitation spectra, it is found that strong intramolecular hydrogen bonding (IHB) interactions present in NPAA molecule. The inclusion complex of NPAA with β-CD is analysed by UV-vis, fluorimetry, FT-IR, 1H NMR, scanning electron microscope and AM 1 method. The above spectral studies show that NPAA forms a 1:1 inclusion complex with β-CD and COOH group present in the β-CD cavity. A mechanism is proposed to explain the inclusion process.

Design, Synthesis, and Pharmacokinetics of a Bone-Targeting Dual-Action Prodrug for the Treatment of Osteoporosis.

PubMed

Xie, Haibo; Chen, Gang; Young, Robert N

2017-08-24

A dual-action bone-targeting prodrug has been designed, synthesized, and evaluated for in vitro and in vivo metabolic stability, in vivo tissue distribution, and rates of release of the active constituents after binding to bones through the use of differentially double-labeled derivatives. The conjugate (general structure 7) embodies the merger of a very potent and proven anabolic selective agonist of the prostaglandin EP4 receptor, compound 5, and alendronic acid, a potent inhibitor of bone resorption, optimally linked through a differentially hydrolyzable linker unit, N-4-carboxymethylphenyl-methyloxycarbonyl-leucinyl-argininyl-para-aminophenylmethylalcohol (Leu-Arg-PABA). Optimized conjugate 16 was designed so that esterase activity will liberate 5 and cathepsin K cleavage of the Leu-Arg-PABA element will liberate alendronic acid. Studies with doubly radiolabeled 16 provide a proof-of-concept for the use of a cathepsin K cleavable peptide-linked conjugate for targeting of bisphosphonate prodrugs to bone and slow release liberation of the active constituents in vivo. Such conjugates are potential therapies for the treatment of bone disorders such as osteoporosis.

Intercalation of anionic organic ultraviolet ray absorbers into layered zinc hydroxide nitrate.

PubMed

Cursino, Ana Cristina Trindade; Gardolinski, José Eduardo Ferreira da Costa; Wypych, Fernando

2010-07-01

Layered zinc hydroxide nitrate (ZHN) was synthesized and nitrate ions were topotactically exchanged with three different anionic species of commercial organic ultraviolet (UV) ray absorbers: 2-mercaptobenzoic acid, 2-aminobenzoic acid, and 4-aminobenzoic acid. The exchange reactions were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-Vis) spectroscopy, and thermal analysis (thermogravimetry, TGA, and differential thermal analysis, DTA). In all the anionic exchanged products, evidence of grafting of the organic species onto the inorganic matrix was obtained. In general, after intercalation/grafting, the UV absorption ability was improved in relation to the use of the parent organic material, showing that layered hydroxide salts (LHS) can be good alternative matrixes for the immobilization of organic species with UV-blocking properties in cosmetic products. Copyright 2010 Elsevier Inc. All rights reserved.

Novel cleavage of reductively aminated glycan-tags by N-bromosuccinimide to regenerate free, reducing glycans.

PubMed

Song, Xuezheng; Johns, Brian A; Ju, Hong; Lasanajak, Yi; Zhao, Chunmei; Smith, David F; Cummings, Richard D

2013-11-15

Glycans that are fluorescently tagged by reductive amination have been useful for functional glycomic studies. However, the existing tags can introduce unwanted properties to the glycans and complicate structural and functional studies. Here, we describe a facile method using N-bromosuccinimide (NBS) to remove the tags and efficiently regenerate free reducing glycans. The regenerated free reducing glycans can be easily analyzed by routine mass spectrometry or retagged with different tags for further studies. This new method can be used to efficiently remove a variety of fluorescent tags installed by reductive amination, including 2-aminobenzoic acid and 2-aminopyridine. NBS treatment essentially transforms the commonly used 2-aminobenzoic linkage to a cleavable linkage. It can be used to cleave printed glycans from microarrays and cleave neoglycopeptides containing a 2-aminobenzoic linker.

Novel cleavage of reductively aminated glycan-tags by N-bromosuccinimide to regenerate free, reducing glycans

PubMed Central

Song, Xuezheng; Johns, Brian A.; Ju, Hong; Lasanajak, Yi; Zhao, Chunmei; Smith, David F.; Cummings, Richard D.

2014-01-01

Glycans that are fluorescently tagged by reductive amination have been useful for functional glycomic studies. However, the existing tags can introduce unwanted properties to the glycans and complicate structural and functional studies. Here we describe a facile method using N-bromosuccinimide (NBS) to remove the tags and efficiently regenerate free reducing glycans. The regenerated free reducing glycans can be easily analyzed by routine mass spectrometry or re-tagged with different tags for further studies. This new method can be used to efficiently remove a variety of fluorescent tags installed by reductive amination, including 2-aminobenzoic acid and 2-aminopyridine. NBS treatment essentially transforms the commonly used 2-aminobenzoic linkage to a cleavable linkage. It can be used to cleave printed glycans from microarrays and cleave neoglycopeptides containing a 2-aminobenzoic linker. PMID:23992636

Carboxylate modified porous graphitic carbon: a new class of hydrophilic interaction liquid chromatography phases.

PubMed

Wahab, M Farooq; Ibrahim, Mohammed E A; Lucy, Charles A

2013-06-18

Stationary phases for hydrophilic interaction liquid chromatography (HILIC) are predominantly based on silica and polymer supports. We present porous graphitic carbon particles with covalently attached carboxylic acid groups (carboxylate-PGC) as a new HILIC stationary phase. PGC particles were modified by adsorbing the diazonium salt of 4-aminobenzoic acid onto the PGC, followed by reduction of the adsorbed salt with sodium borohydride. The newly developed carboxylate-PGC phase exhibits different selectivity than that of 35 HPLC columns, including bare silica, zwitterionic, amine, reversed, and unmodified PGC phases. Carboxylate-PGC is stable from pH 2.0 to 12.6, yielding reproducible retention even at pH 12.6. Characterization of the new phase is presented by X-ray photoelectron spectroscopy, thermogravimetry, zeta potentials, and elemental analysis. The chromatographic performance of carboxylate-PGC as a HILIC phase is illustrated by separations of carboxylic acids, nucleotides, phenols, and amino acids.

Hydrophilic interaction liquid chromatography of anthranilic acid-labelled oligosaccharides with a 4-aminobenzoic acid ethyl ester-labelled dextran hydrolysate internal standard.

PubMed

Neville, David C A; Alonzi, Dominic S; Butters, Terry D

2012-04-13

Hydrophilic interaction liquid chromatography (HILIC) of fluorescently labelled oligosaccharides is used in many laboratories to analyse complex oligosaccharide mixtures. Separations are routinely performed using a TSK gel-Amide 80 HPLC column, and retention times of different oligosaccharide species are converted to glucose unit (GU) values that are determined with reference to an external standard. However, if retention times were to be compared with an internal standard, consistent and more accurate GU values would be obtained. We present a method to perform internal standard-calibrated HILIC of fluorescently labelled oligosaccharides. The method relies on co-injection of 4-aminobenzoic acid ethyl ester (4-ABEE)-labelled internal standard and detection by UV absorption, with 2-AA (2-aminobenzoic acid)-labelled oligosaccharides. 4-ABEE is a UV chromophore and a fluorophore, but there is no overlap of the fluorescent spectrum of 4-ABEE with the commonly used fluorescent reagents. The dual nature of 4-ABEE allows for accurate calculation of the delay between UV and fluorescent signals when determining the GU values of individual oligosaccharides. The GU values obtained are inherently more accurate as slight differences in gradients that can influence retention are negated by use of an internal standard. Therefore, this paper provides the first method for determination of HPLC-derived GU values of fluorescently labelled oligosaccharides using an internal calibrant. Copyright © 2012 Elsevier B.V. All rights reserved.

21 CFR 310.527 - Drug products containing active ingredients offered over-the-counter (OTC) for external use as...

Code of Federal Regulations, 2012 CFR

2012-04-01

... offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention. 310.527... products containing active ingredients offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention. (a) Amino acids, aminobenzoic acid, ascorbic acid, benzoic acid, biotin and...

21 CFR 310.527 - Drug products containing active ingredients offered over-the-counter (OTC) for external use as...

Code of Federal Regulations, 2014 CFR

2014-04-01

... offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention. 310.527... products containing active ingredients offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention. (a) Amino acids, aminobenzoic acid, ascorbic acid, benzoic acid, biotin and...

21 CFR 310.527 - Drug products containing active ingredients offered over-the-counter (OTC) for external use as...

Code of Federal Regulations, 2013 CFR

2013-04-01

... offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention. 310.527... products containing active ingredients offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention. (a) Amino acids, aminobenzoic acid, ascorbic acid, benzoic acid, biotin and...

Copper and dyes enhance laccase production in gamma-proteobacterium JB.

PubMed

Malhotra, Kanam; Sharma, Prince; Capalash, Neena

2004-07-01

Laccase production in gamma-proteobacterium JB was enhanced 13-fold by adding 0.1 mM CuSO(4) 24 h after the onset of growth. Ethidium bromide (2.5 microM), Malachite Green, Phenol Red and Thymol Blue (10 microM each) enhanced laccase production 17-, 19-, 4- and 2-fold, respectively. Among the fourteen aromatic/organic compounds tried, p-aminobenzoic acid and an industrial effluent, from where the organism was isolated, showed 1.2- and 1.26-fold increases in production.

Removing Peanut Allergen Ara h 1 from Peanut Extracts Using p-Aminobenzamidine

USDA-ARS?s Scientific Manuscript database

Rationale: Ara h 1 is one of 3 major allergens in peanut. Removing Ara h 1 from a peanut extract may produce a hypoallergenic peanut extract for immunotherapy and other purposes. Methods: Peanut extracts were treated overnight with and without 10 mM p-aminobenzamidine (pABA, a protease inhibitor) i...

Ethyl-p-aminobenzoate (Benzocaine): efficacy as an anesthetic for five species of freshwater fish

USGS Publications Warehouse

Dawson, V.K.; Gilderhus, P.A.

1979-01-01

Ethyl-p-aminobenzoate (benzocaine) was tested for its efficacy as an anesthetic for rainbow trout (Salmo gairdnerii, brown trout (Salmo truttas, northern pike (Esox lucius). carp (Cyprinus carpio), and largemouth bass (Mieropterus salmoidesi. Since benzocaine is not water soluble, it was applied with acetone as a carrier. Concentrations of 100 to 200 mg!l were required for large adult northern pike, compared with 50 to 100 mg/l for small fish. Rates of sedation and recovery were slower in cold water than in warm water. Water hardness had little influence on the activity of benzocaine. Fish were anesthetized faster and recovered more slowly in acid than in alkaline water. Benzocaine produced deep anesthesia, but concentrations that rendered the fish handleable within 5 min were generally not safe for exposures longer than 15 min. Concentrations of benzocaine efficacious for fish were not acutely toxic to eggs of coho salmon (Oncorhynchus kisutch), chinook salmon (Oncorhynchus tshauiytschas, rainbow trout, brown trout, or lake trout (Salvelinus namaycush). Benzocaine is not registered for fishery use and is neither more effective nor safer than the registered anesthetic, tricaine methanesulfonate (MS-222l.

Metabolism of benoxinate in humans.

PubMed

Kasuya, F; Igarashi, K; Fukui, M

1987-04-01

The metabolism of benoxinate hydrochloride [2-(diethylamino)ethyl 4-amino-3-butoxybenzoate monohydrochloride; oxybuprocaine] was examined in humans after administration of a single oral dose. The drug was almost completely absorbed and was rapidly excreted in the urine (92.1% of dose in 9 h). Nine metabolites and unchanged drug were isolated from the urine and identified by comparison of TLC, GC, and GC-MS with authentic compounds. Any metabolites reflecting initial loss of the butyl side chain of benoxinate could not be detected. This suggests that the ester portion is metabolized more rapidly than the O-butyl side chain. 3-Butoxy-4-aminobenzoic acid, the hydrolyzed product of benoxinate, was primarily excreted (70-90% of dose) as the glucuronide together with a trace of the glycine conjugate (0.35% of dose). In addition, 3-butoxy-4-acetylaminobenzoic acid, 3-hydroxy-4-aminobenzoic acid, and 3-hydroxy-4-acetylaminobenzoic acid were identified, the latter two being detected partly as the glucuronides (1.20 and 1.43% of dose, respectively).

A spectrophotometric determination of cyanate using reaction with 2-aminobenzoic acid.

PubMed

Guilloton, M; Karst, F

1985-09-01

A specific method has been devised for the assay of cyanate, based on the reaction with 2-aminobenzoic acid. Cyclization of the product in 6 N HCl results in the formation of 2,4(1H,3H)-quinazolinedione. Cyanate content of the samples can be measured by their absorbances at 310 nm. Alternatively, the second derivatives of the spectra can be recorded; the peak-to-peak height between the first maximum (330 nm) and the first minimum (317 nm) was shown to be proportional to the cyanate content. This method is suitable for the estimation of cyanate in aqueous solutions in the concentration range 0.01 to 2 mM. When added to blood plasma, cyanate could be detected down to 0.1 mM.

21 CFR 310.527 - Drug products containing active ingredients offered over-the-counter (OTC) for external use as...

Code of Federal Regulations, 2011 CFR

2011-04-01

... offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention. 310.527... for hair loss prevention. (a) Amino acids, aminobenzoic acid, ascorbic acid, benzoic acid, biotin and... in OTC drug products for external use as hair growers or for hair loss prevention. There is a lack of...

Novel Strip Test for Circulating Hormones

DTIC Science & Technology

1996-10-01

estrone- 3 -glucuronide was combined with 1 equivalent of 4-amino-benzo-15-crown-5 and 1.2 equivalents of 1 -ethyl- 3 -( 3 - dimethylaminopropyl )carbodiimide...solution containing 5 mg/ml of El-g and 10 mg/ml of 1 -ethyl- 3 -( 3 -dimethylamino-propyl)carbodiimide (EDC) in water at pH 4.2. Fibers are then rinsed with... hydrochloride in water at pH 4.0. The mixture was stirred at room temperature for 48 hours and the resulting estrone- 3 -glucuronide-4-amino-benzo-15-crown

Arylamine N-acetyltransferase 1 in situ N-acetylation on CD3+ peripheral blood mononuclear cells correlate with NATb mRNA and NAT1 haplotype.

PubMed

Salazar-González, Raúl A; Turiján-Espinoza, Eneida; Hein, David W; Niño-Moreno, Perla C; Romano-Moreno, Silvia; Milán-Segovia, Rosa C; Portales-Pérez, Diana P

2018-02-01

Human arylamine N-acetyltransferase 1 (NAT1) is responsible for the activation and elimination of xenobiotic compounds and carcinogens. Genetic polymorphisms in NAT1 modify both drug efficacy and toxicity. Previous studies have suggested a role for NAT1 in the development of several diseases. The aim of the present study was to evaluate NAT1 protein expression and in situ N-acetylation capacity in peripheral blood mononuclear cells (PBMC), as well as their possible associations with the expression of NAT1 transcript and NAT1 genotype. We report NAT1 protein, mRNA levels, and N-acetylation in situ activity for PBMC obtained from healthy donors. NAT1-specific protein expression was higher in CD3+ cells than other major immune cell subtypes (CD19 or CD56 cells). N-acetylation of pABA varied markedly among the PBMC of participants, but correlated very significantly with levels of NAT1 transcripts. NAT1*4 subjects showed significantly (p = 0.017) higher apparent pABA V max of 71.3 ± 3.7 versus the NAT1*14B subjects apparent V max of 58.5 ± 2.5 nmoles Ac-pABA/24 h/million cells. Levels of pABA N-acetylation activity at each concentration of substrate evaluated also significantly correlated with NAT1 mRNA levels for all samples (p < 0.0001). This highly significant correlation was maintained for samples with the NAT1*4 (p = 0.002) and NAT1*14B haplotypes (p = 0.0106). These results provide the first documentation that NAT1-catalyzed N-acetylation in PBMC is higher in T cell than in other immune cell subtypes and that individual variation in N-acetylation capacity is dependent upon NAT1 mRNA and NAT1 haplotype.

Halogeno-substituted 2-aminobenzoic acid derivatives for negative ion fragmentation studies of N-linked carbohydrates.

PubMed

Harvey, David J

2005-01-01

Negative ion electrospray mass spectra of high-mannose N-linked glycans derivatised with 2-aminobenzoic acids and ionised from solutions containing ammonium hydroxide gave prominent [M-H](-) ions accompanied by weaker [M-2H](2-) ions. Fragmentation of both types of ions gave prominent singly charged glycosidic cleavage ions containing the derivatised reducing terminus and ions from the non-reducing terminus that appeared to be products of cross-ring cleavages. Differentiation of these two groups of ions was conveniently achieved in a single spectrum by use of chloro- or bromo-substituted benzoic acids in order to label ions containing the derivative with an atom with a distinctive isotope pattern. Fragmentation of the doubly charged ions gave more abundant fragments, both singly and doubly charged, than did fragmentation of the singly charged ions, but information of chain branching was masked by the appearance of prominent ions produced by internal cleavages. Copyright (c) 2005 John Wiley & Sons, Ltd.

Oxybuprocaine and five metabolites simultaneously determined in urine by gas chromatography and gas chromatography-mass spectrometry after extraction with Extrelut.

PubMed

Kasuya, F; Igarashi, K; Fukui, M

1987-05-01

We describe a gas-liquid chromatographic (GC) method for determination of oxybuprocaine, and a gas chromatographic-mass spectrometric (GC-MS) method for simultaneous determination of four of its nine metabolites in urine. We used an Extrelut column to simply and rapidly extract oxybuprocaine and its metabolites from urine. For the GC-MS analyses, we monitored the characteristic fragment ions at m/z 353, 395, 369, 411, and 235 for 3-butoxy-4-aminobenzoic acid (metabolite 2, M-2), 3-butoxy-4-acetylaminobenzoic acid (M-3), 3-hydroxy-4-aminobenzoic acid (M-4), 3-hydroxy-4-acetylaminobenzoic acid (M-5), and methaqualone (internal standard), respectively. We quantified the glucuronide of M-2 after enzymic treatment. The assay's selectivity and reproducibility (within-day and between-day CVs less than 8% for all metabolites) make it applicable to determine oxybuprocaine and its metabolites in human urine. Mean 9-h urinary excretion of oxybuprocaine and its five metabolites from four healthy volunteers was 89.2% after a 100-mg oral dose.

Phase transition and intramolecular hydrogen bonding in nitro derivatives of ortho-hydroxy acetophenones

NASA Astrophysics Data System (ADS)

Filarowski, A.; Kochel, A.; Koll, A.; Bator, G.; Mukherjee, S.

2006-03-01

The crystal structures of two ortho-hydroxy aryl ketones (5-chloro-3-nitro-2-hydroxyacetophenone, 5-methyl-3-nitro-2-hydroxyacetophenone and the complex 5-chloro-3-nitro-2-hydroxyacetophenone with 2-aminobenzoic acid (anthranilic acid)) were determined by X-ray diffraction. The existence of an intramolecular hydrogen bond of enol character between the hydroxyl and acetyl groups was found by the X-ray method. The enol character was also confirmed by DFT (B3LYP/6-31+G(d,p)) calculations. A phase transition was found at 138 K in 5-chloro-3-nitro-2-hydroxyacetophenone. This phase transition was investigated by differential scanning calorimetry (DSC), dilatometry, and the dielectric method. A study of the nitro-group dynamics in the ortho-hydroxy acetophenones was carried out with DFT (B3LYP/6-31+G(d,p)) calculations.

Mass spectrometric-based stable isotopic 2-aminobenzoic acid glycan mapping for rapid glycan screening of biotherapeutics.

PubMed

Prien, Justin M; Prater, Bradley D; Qin, Qiang; Cockrill, Steven L

2010-02-15

Fast, sensitive, robust methods for "high-level" glycan screening are necessary during various stages of a biotherapeutic product's lifecycle, including clone selection, process changes, and quality control for lot release testing. Traditional glycan screening involves chromatographic or electrophoretic separation-based methods, and, although reproducible, these methods can be time-consuming. Even ultrahigh-performance chromatographic and microfluidic integrated LC/MS systems, which work on the tens of minute time scale, become lengthy when hundreds of samples are to be analyzed. Comparatively, a direct infusion mass spectrometry (MS)-based glycan screening method acquires data on a millisecond time scale, exhibits exquisite sensitivity and reproducibility, and is amenable to automated peak annotation. In addition, characterization of glycan species via sequential mass spectrometry can be performed simultaneously. Here, we demonstrate a quantitative high-throughput MS-based mapping approach using stable isotope 2-aminobenzoic acid (2-AA) for rapid "high-level" glycan screening.

Separation of saccharides derivatized with 2-aminobenzoic acid by capillary electrophoresis and their structural consideration by nuclear magnetic resonance.

PubMed

He, Liping; Sato, Kae; Abo, Mitsuru; Okubo, Akira; Yamazaki, Sunao

2003-03-01

Saccharides including mono- and disaccharides were quantitatively derivatized with 2-aminobenzoic acid (2-AA). These derivatives were then separated by capillary zone electrophoresis with UV detection using 50mM sodium phosphate buffer as the running electrolyte solution. In particular, the saccharide derivatives with the same molecular weight as 2-AA aldohexoses (mannose and glucose) and 2-AA aldopentoses (ribose and xylose) were well separated. The underlying reasons for separation were explored by studying their structural data using 1H and 13C NMR. It was found that the configurational difference between their hydroxyl group at C2 or C3 could cause the difference in Stokes' radii between their molecules and thus lead to different electrophoretic mobilities. The correlation between the electrophoretic behavior of these carbohydrate derivatives and their structures was studied utilizing the calculated molecular models of the 2-AA-labeled mannose, glucose, ribose, and xylose.

Nutrient supplements boost yeast transformation efficiency

PubMed Central

Yu, Sheng-Chun; Dawson, Alexander; Henderson, Alyssa C.; Lockyer, Eloise J.; Read, Emily; Sritharan, Gayathri; Ryan, Marjah; Sgroi, Mara; Ngou, Pok M.; Woodruff, Rosie; Zhang, Ruifeng; Ren Teen Chia, Travis; Liu, Yu; Xiang, Yiyu; Spanu, Pietro D.

2016-01-01

Efficiency of yeast transformation is determined by the rate of yeast endocytosis. The aim of this study was to investigate the effect of introducing amino acids and other nutrients (inositol, adenine, or p-aminobenzoic acid) in the transformation medium to develop a highly efficient yeast transformation protocol. The target of rapamycin complex 1 (TORC1) kinase signalling complex influences the rate of yeast endocytosis. TORC signaling is induced by amino acids in the media. Here, we found that increasing the concentration of amino acids and other nutrients in the growth media lead to an increase yeast transformation efficiency up to 107 CFU per μg plasmid DNA and per 108 cells with a 13.8 kb plasmid DNA. This is over 130 times that of current published methods. This improvement may facilitate more efficient experimentation in which transformation efficiency is critical, such as yeast two-hybrid screening. PMID:27760994

Simple methods to reduce major allergen Ara h 1 and Ana o 1/2 in peanut and cashew extracts

USDA-ARS?s Scientific Manuscript database

Whole peanut extracts are usually used in immunotherapy but may have side effects. Reducing major peanut allergen(s) in the extracts may reduce the side effects. Three simple methods were evaluated to reduce major allergen Ara h 1 from a peanut extract: (1) treatment with p-aminobenzamidine (pABA); ...

Study of the photochemical transformation of 2-ethylhexyl 4-(dimethylamino)benzoate (OD-PABA) under conditions relevant to surface waters.

PubMed

Calza, P; Vione, D; Galli, F; Fabbri, D; Dal Bello, F; Medana, C

2016-01-01

We studied the aquatic environmental fate of 2-ethylhexyl 4-(dimethylamino)benzoate (OD-PABA), a widespread sunscreen, to assess its environmental persistence and photoinduced transformation. Direct photolysis is shown to play a key role in phototransformation, and this fast process is expected to be the main attenuation route of OD-PABA in sunlit surface waters. The generation of transformation products (TPs) was followed via HPLC/HRMS. Five (or four) TPs were detected in the samples exposed to UVB (or UVA) radiation, respectively. The main detected TPs of OD-PABA, at least as far as HPLC-HRMS peak areas are concerned, would involve a dealkylation or hydroxylation/oxidation process in both direct photolysis and indirect phototransformation. The latter was simulated by using TiO2-based heterogeneous photocatalysis, involving the formation of nine additional TPs. Most of them resulted from the further degradation of the primary TPs that can also be formed by direct photolysis. Therefore, these secondary TPs might also occur as later transformation intermediates in natural aquatic systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhanced cytogenetic and antineoplastic effects by the combined action of two esteric steroidal derivatives of nitrogen mustards.

PubMed

Papageorgiou, A; Nikolaropoulos, S S; Arsenou, E S; Karaberis, E; Mourelatos, D; Kotsis, A; Chryssogelou, E

1999-01-01

The authors studied the effect of two modified steroids containing different proportions (%) of alkylating agents alone or in combination on sister chromatid exchange (SCE) rates and on human lymphocyte proliferation kinetics. The antitumor activity of these compounds was tested on leukemia P388- and leukemia L1210-bearing mice. The two chemicals in mixtures enhance SCE induction and antitumor activity in a synergistic manner. The homo-aza-steroidal ester of p-bis(2-chloroethyl)aminophenyl acetic acid was found to be more effective than the homo-aza-steroidal ester of o-bis(2-chloroethyl)aminobenzoic acid in causing cytogenetic damage and antineoplastic activity. A correlation was observed between the magnitude of the SCE response and the depression of the cell proliferation index. The order of the antitumor effectiveness of the five different treatments tested coincided with the order of the cytogenetic effects they induced.

Use of Polyamine Derivatives as Selective Histone Deacetylase Inhibitors

PubMed Central

Woster, Patrick M.

2014-01-01

Histone acetylation and deacetylation, mediated by histone acetyltransferase and the 11 isoforms of histone deacetylase, play an important role in gene expression. Histone deacetylase inhibitors have found utility in the treatment of cancer by promoting the reexpression of aberrantly silenced genes that code for tumor suppressor factors. It is unclear which of the 11 histone deacetylase isoforms are important in human cancer. We have designed a series of polyaminohydroxamic acid (PAHA) and polyaminobenzamide (PABA) histone deacetylase inhibitors that exhibit selectivity among four histone deacetylase isoforms. Although all of the active inhibitors promote reexpression of tumor suppressor factors, they produce variable cellular effects ranging from stimulation of growth to cytostasis and cytotoxicity. This chapter describes the procedures used to quantify the global and isoform-specific inhibition caused by these inhibitors, and techniques used to measure cellular effects such as reexpression of tumor suppressor proteins and hyperacetylation of histones H3 and H4. Procedures are also described to examine the ability of PAHAs and PABAs to utilize the polyamine transport system and to induce overexpression of the early apoptotic factor annexin A1. PMID:21318894

Characterization of carbohydrates using highly fluorescent 2-aminobenzoic acid tag following gel electrophoresis of glycoproteins.

PubMed

Anumula, K R; Du, P

1999-11-15

Application of the most sensitive fluorescent label 2-aminobenzoic acid (anthranilic acid, AA) for characterization of carbohydrates from the glycoproteins ( approximately 15 pmol) separated by polyacrylamide gel electrophoresis is described. AA label is used for the determination of both monosaccharide composition and oligosaccharide map. For the monosaccharide determination, bands containing the glycoprotein of interest are excised from the polyvinylidene fluoride (PVDF) membrane blots, hydrolyzed in 20% trifluoroacetic acid, derivatized, and analyzed by C-18 reversed-phase high-performance liquid chromatography. For the oligosaccharide mapping, bands were digested with peptide N-glycosidase F (PNGase F) in order to release the N-linked oligosaccharides, derivatized, and analyzed by normal-phase anion-exchange chromatography. For convenience, the PNGase F digestion was performed in 1:100 diluted ammonium hydroxide overnight. The oligosaccharide yield from ammonium hydroxide-PNGase F digestion was better or equal to all the other reported procedures, and the presumed "oligosaccharide-amine" product formed in the reaction mixture did not interfere with labeling of the oligosaccharides under the conditions used for derivatization. Sequencing of oligosaccharides can be performed using the same mapping method following treatment with an array of glycosidases. In addition, the mapping method is useful for determining the relative and simultaneous distribution of sialic acid and fucose. Copyright 1999 Academic Press.

Cocrystal solubility product analysis - Dual concentration-pH mass action model not dependent on explicit solubility equations.

PubMed

Avdeef, Alex

2017-12-15

A novel general computational approach is described to address many aspects of cocrystal (CC) solubility product (K sp ) determination of drug substances. The CC analysis program, pDISOL-X, was developed and validated with published model systems of various acid-base combinations of active pharmaceutical ingredients (APIs) and coformers: (i) carbamazepine cocrystal systems with 4-aminobenzoic acid, cinnamic acid, saccharin, and salicylic acid, (ii) for indomethacin with saccharin, (iii) for nevirapine with maleic acid, saccharin, and salicylic acid, and (iv) for gabapentin with 3-hydroxybenzoic acid. In all systems but gabapentin, the coformer is much more soluble than the API. The model systems selected are those with available published dual concentration-pH data, one set for the API and one set for the coformer, generally measured at eutectic points (thermodynamically-stable three phases: solution, cocrystal, and crystalline API or coformer). The carbamazepine-cinnamic acid CC showed a substantial elevation in the API equilibrium concentration above pH5, consistent with the formation of a complex between carbamazepine and cinnamate anion. The analysis of the gabapentin:3-hydroxybenzoic acid 1:1 CC system indicated four zones of solid suspensions: coformer (pH<3.25), coformer and cocrystal eutectic (pH3.25-4.44), cocrystal (pH4.44-5.62), and API (pH>5.62). The general approach allows for testing of many possible equilibrium models, including those comprising drug-coformer complexation. The program calculates the ionic strength at each pH. From this, the equilibrium constants are adjusted for activity effects, based on the Stokes-Robinson hydration theory. The complete speciation analysis of the CC systems may provide useful insights into pH-sensitive dissolution effects that could potentially influence bioavailability. Copyright © 2017 Elsevier B.V. All rights reserved.

Enzymatic Synthesis of Lignin-Based Concrete Dispersing Agents.

PubMed

Jankowska, Dagmara; Heck, Tobias; Schubert, Mark; Yerlikaya, Alpaslan; Weymuth, Christophe; Rentsch, Daniel; Schober, Irene; Richter, Michael

2018-03-15

Lignin is the most abundant aromatic biopolymer, functioning as an integral component of woody materials. In its unmodified form it shows limited water solubility and is relatively unreactive, so biotechnological lignin valorisation for high-performance applications is greatly underexploited. Lignin can be obtained from the pulp and paper industry as a by-product. To expand its application, a new synthesis route to new dispersing agents for use as concrete additives was developed. The route is based on lignin functionalisation by enzymatic transformation. Screening of lignin-modifying systems resulted in functionalised lignin polymers with improved solubility in aqueous systems. Through grafting of sulfanilic acid or p-aminobenzoic acid by fungal laccases, lignin became soluble in water at pH≤4 or pH≤7, respectively. Products were analysed and evaluated in miniaturised application tests in cement paste and mortar. Their dispersing properties match the performance criteria of commercially available lignosulfonates. The study provides examples of new perspectives for the use of lignin. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans.

PubMed

Kang, Ji-Yeon; Kwon, Ohsuk; Gil, Jin Young; Oh, Doo-Byoung

2016-05-15

Mannose-6-phosphate (M-6-P) glycan analysis is important for quality control of therapeutic enzymes for lysosomal storage diseases. Here, we found that the analysis of glycans containing two M-6-Ps was highly affected by the hydrophilicity of the elution solvent used in high-performance liquid chromatography (HPLC). In addition, the performances of three fluorescent tags--2-aminobenzoic acid (2-AA), 2-aminobenzamide (2-AB), and 3-(acetyl-amino)-6-aminoacridine (AA-Ac)--were compared with each other for M-6-P glycan analysis using HPLC and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The best performance for analyzing M-6-P glycans was shown by 2-AA labeling in both analyses. Copyright © 2016 Elsevier Inc. All rights reserved.

Mercury photolytic transformation affected by low-molecular-weight natural organics in water.

PubMed

He, Feng; Zheng, Wang; Liang, Liyuan; Gu, Baohua

2012-02-01

Mechanisms by which dissolved organic matter (DOM) mediates the photochemical reduction of Hg(II) in aquatic ecosystems are not fully understood, owing to the heterogeneous nature and complex structural properties of DOM. In this work, naturally occurring aromatic compounds including salicylic, 4-hydrobenzoic, anthranilic, 4-aminobenzoic, and phthalic acid were systematically studied as surrogates for DOM in order to gain an improved mechanistic understanding of these compounds in the photoreduction of Hg(II) in water. We show that the photoreduction rates of Hg(II) are influenced not only by the substituent functional groups such as -OH, -NH(2) and -COOH on the benzene ring, but also the positioning of these functional groups on the ring structure. The Hg(II) photoreduction rate decreases in the order anthranilic acid>salicylic acid>phthalic acid according to the presence of the -NH(2), -OH, -COOH functional groups on benzoic acid. The substitution position of the functional groups affects reduction rates in the order anthranilic acid>4-aminobenzoic acid and salicylic acid>4-hydroxybenzoic acid. Reduction rates correlate strongly with ultraviolet (UV) absorption of these compounds and their concentrations, suggesting that the formation of organic free radicals during photolysis of these compounds is responsible for Hg(II) photoreduction. These results provide insight into the role of low-molecular-weight organic compounds and possibly DOM in Hg photoredox transformation and may thus have important implications for understanding Hg geochemical cycling in the environment. Copyright © 2011 Elsevier B.V. All rights reserved.

EFFECTS OF ANESTHESIA (MS222) ON LIVER BIOTRANSFORMATION IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

EPA Science Inventory

Tricaine methanesulfonate (3-aminobenzoic acid ethyl ester methanesulfonate; MS222) is a widely used fish anaesthetic. While there have been several studies addressing the impact of its use on subsequently measured biotransformation rates, the measured influence on normal functio...

EFFECTS OF ANESTHESIA (TRICAINE METHANESULFONATE, MS-222) BIOTRANSFORMATION IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

EPA Science Inventory

Tricaine methanesulfonate (3-aminobenzoic acid eithyl ester methanesulfonate, tricaine, MS-222, Finquel), an anesthetic for fish, has been used extensively in aquatic toxicology to allow surgical procedures for in vivo studies and to permit in vitro preparations of isolated perfu...

Synthesis, growth, structural, optical and thermal properties of an organic single crystal: 4-nitroaniline 4-aminobenzoic acid.

PubMed

Silambarasan, A; Rajesh, P; Ramasamy, P

2014-01-24

The organic single crystals of 4-nitroaniline 4-aminobenzoic acid (4NAABA) were grown from ethanol solvent. The lattice parameters of the grown crystal have been confirmed from single crystal XRD analysis. The powder XRD pattern shows the various planes of grown crystal. The FTIR and (1)H NMR spectral analysis confirm the presence of various functional groups and the placement of proton in 4NAABA compound respectively. The UV absorption was carried out which shows the cutoff wavelength around 459 nm. The optical band gap of the crystal has been evaluated from the transmission spectra and absorption coefficient by extrapolation technique. In addition, a fluorescence spectral analysis is carried out for 4NAABA crystals. The thermal properties of crystals were evaluated from thermogravimetrical analysis. It shows that the grown crystal is stable up to 160°C and the crystal has sharp melting point at 151°C. Copyright © 2013 Elsevier B.V. All rights reserved.

Selection of G1-PABA as a GPER1 ligand compared to phenol red via a ligand-based virtual screening coupled to molecular dynamics simulations and its anti-proliferative effects on breast cancer cells.

PubMed

Jose, Correa-Basurto; Trujillo-Ferrara, Jose G; Irene, Mendoza-Lujambio; Alfonso, Duenas-Gonzalez; Alma, Chavez-Blanco; Marlet, Martinez-Archundia; Bello, M; Ruben, Garcia Sanchez Jose; Jonathan, Fragoso-Vazquez Manuel; David, Mendez-Luna; Berenice, Prestegui-Martel; Alberto, Martinez-Munoz

2018-05-10

Recent reports have demonstrated the role of the G protein-coupled estrogen receptor (GPER1) on the growth and proliferation of breast cancer cells. The coupling of GPER1 to estrogen, tamoxifen or fulvestrant triggers cellular signaling pathways (PI3K and ERK) related to cell proliferation. In an effort to develop new therapeutic strategies against breast cancer, we performed an in silico study to explore the binding pose of a set of designed G15 and G1 analogue compounds, including phenol red. First, we included a carboxyl group instead of the acetyl group from G1 to form amides with several moieties to increase the affinity for GPER1. Then, all the target compounds were submitted to an in silico ADMET study. Then, the ligands were coupled to GPER1 using ligand-based virtual screening to finally achieve molecular dynamics simulations of the best molecule on GPER1, as well as of phenol red, to explore its recognition properties. According to the in silico ADMET and docking studies, the best molecule was named G1-PABA ((3aS,4R,9bR)-4-(6-bromobenzo[d][1,3]dioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-carboxylic acid). It was synthesized and assayed in vitro in breast cancer (MCF-7 and MDA-MB-231) and normal (MCF-10A) cell lines. Experimental assays showed that the target compound was able to decrease cell proliferation, showing IC50 values of 15.93 M, 52.92 M and 32.45 M in the MCF-7, MDA-MB-231 and MCF-10A cell lines, respectively, after 72 h of treatment. Interestingly, the target compound showed better IC50 values without phenol red, suggesting that phenol red could interfere with the G1-PABA action at GPER, which is present in MCF-7 cells according to PCR studies and explains the cell proliferation effects. In conclusion, a concentration-dependent inhibition of cell proliferation occurred with G1-PABA in the assayed cell lines and could be due to its action on GPER1. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Collision-induced fragmentation of negative ions from N-linked glycans derivatized with 2-aminobenzoic acid.

PubMed

Harvey, David J

2005-05-01

N-Linked glycans from bovine ribonuclease B, chicken ovalbumin, bovine fetuin, porcine thyroglobulin and human alpha(1)-acid glycoprotein were derivatized with 2-aminobenzoic acid by reductive amination and their tandem mass spectra were recorded by negative ion electrospray ionization with a quadrupole time-of-flight mass spectrometer. Derivatives were also prepared from 2-amino-5-methyl- and 2-amino-4,5-dimethoxybenzoic acid in order to confirm the identity of fragment ions containing the reducing terminus. Major fragments from the [M - H](-) ions from the neutral glycans retained the derivative (Y-type cleavages) and provided information on sequence and branching. Other major fragments were products of A-type cross-ring cleavages giving information on antenna structure. Singly doubly and triply charged ions were formed from sialylated glycans. They produced major fragments by loss of sialic acid and a series of singly charged ions that were similar to those from the neutral analogues. Doubly charge ions were also produced by the neutral glycans and were fragmented to form product ions with one and two charges. Again, the fragment ions with a single charge were similar to those from the singly charged parents, but branching information was less obvious because of the occurrence of more abundant ions produced by multiple cleavages. Detection limits were around 200 fmol (3 : 1 signal-to-noise ratio). Copyright 2005 John Wiley & Sons, Ltd.

Inhibition of recombinant Pneumocystis carinii dihydropteroate synthetase by sulfa drugs.

PubMed Central

Hong, Y L; Hossler, P A; Calhoun, D H; Meshnick, S R

1995-01-01

Forty-four sulfa drugs were screened against crude preparations of recombinant Pneumocystis carinii dihydropteroate synthetase. The apparent Michaelis-Menten constants (Km) for p-aminobenzoic acid and 7,8-dihydro-6-hydroxymethylpterin pyrophosphate were 0.34 +/- 0.02 and 2.50 +/- 0.71 microM, respectively. Several sulfa drugs, including sulfathiazole, sulfachlorpyridazine, sulfamethoxypyridazine, and sulfathiourea, inhibited dihydropteroate synthetase approximately as well as sulfamethoxazole, as determined by the concentrations which cause 50% inhibition and/or by Ki. For all sulfones and sulfonamides tested, unsubstituted p-amino groups were necessary for activity, and sulfonamides containing an N1-heterocyclic substituent were found to be the most effective inhibitors. Folate biosynthesis in isolated intact P. carinii was approximately equally sensitive to inhibition by sulfamethoxazole, sulfachlorpyridazine, sulfamethoxypyridazine, sulfisoxazole, and sulfathiazole. Two of these drugs, sulfamethoxypyridazine and sulfisoxazole, are known to be less toxic than sulfamethoxazole and should be further evaluated for the treatment of P. carinii pneumonia. PMID:7486915

Bioorganometallic chemistry. 8. The molecular recognition of aromatic and aliphatic amino acids and substituted aromatic and aliphatic carboxylic acid guests with supramolecular ({eta}{sup 5}-pentamethylcyclopentadienyl)rhodium - nucleobase, nucleoside, and nucleotide cyclic trimer hosts via non-covalent {pi}-{pi} and hydrophobic interactions in water: Steric, electronic, and conformational parameters

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

Chen, H.; Ogo, Seiji; Fish, R.H.

Molecular recognition, via non-covalent processes such as hydrogen bonding, {pi}-{pi}, and hydrophobic interactions, is an important biological phenomenon for guests, such as drugs, proteins, and other important biological molecules with, for example, host DNA/RNA. We have studied a novel molecular recognition process using guests that encompass aromatic and aliphatic amino acids [L-alanine, L-glutamine (L-Gln), L-histidine, L-isoleucine(L-Ile), L-leucine(L-Leu), L-phenylalanine(L-Phe), L-proline, L-tryptophan(L-Trp), L-valine(L-Val)], substituted aromatic carboxylic acids o-, m-, p-aminobenzoic acids (G1-3), benzoic acid (G4), phenylacetic acid (G5), p-methoxyphenylacetic acid (G6), o-methyoxybenozoic acid (G9), o-nitrobenzoic acid (G10), and aliphatic carboxylic acids [cyclohexylacetic acid (G7), 1-adamantanecarboxylic acid (G8)] with supramolecular, bioorganometallic hosts, ({eta}{supmore » 5}-pentamethylcyclopentadienyl)rhodium (Cp{sup *}Rh)-nucleobase, nucleoside, and nucleotide cyclic trimer complexes in aqueous solution at pH 7, utilizing {sup 1}H NMR, NOE, and molecular modeling techniques, and, as well, determining association constants (K{sub a}) and free energies of complexation ({Delta}{degree}G). The host-guest complexation occurs predominantly via non-covalent {pi}-{pi}, hydrophobic, and possible subtle H-bonding interactions, with steric, electronic, and molecular conformational parameters as important criteria. 8 refs., 6 figs., 3 tabs.« less

An azoreductase, aerobic NADH-dependent flavoprotein discovered from Bacillus sp.: functional expression and enzymatic characterization.

PubMed

Ooi, Toshihiko; Shibata, Takeshi; Sato, Reiko; Ohno, Hiroaki; Kinoshita, Shinichi; Thuoc, Tran Linh; Taguchi, Seiichi

2007-05-01

The gene coding for an azoreductase, designated as an azrA, was cloned by polymerase chain reaction amplification from the genomic DNA of Bacillus sp. strain B29 isolated from soil. The azrA encoded a protein of 208 amino acids with calculated molecular mass of 22,766 Da. The enzyme was heterologously expressed in Escherichia coli with a strong band of 23 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Purified recombinant AzrA was a homodimer with a native molecular mass of 48 kDa containing two molecules of flavin mononucleotide (FMN; oxidized). This activity was oxygen insensitive and was nicotinamide adenine dinucleotide (reduced form; NADH) dependent. Recombinant AzrA exhibited a broad pH stability between 6 and 10 with a temperature optimum of 60-80 degrees C. The enzyme cleaved the model azo compound of methyl red [MR, 4'-(dimethylamino)-azobenzene-2-carboxylic acid] into 2-aminobenzoic acid and N, N'-dimethyl-p-phenylenediamine by ping-pong mechanism. The enzyme was not only able to decolorize MR but also able to decolorize sulfonated azo dyes such as Orange I and Acid Red 88.

Quantitative twoplex glycan analysis using 12C6 and 13C6 stable isotope 2-aminobenzoic acid labelling and capillary electrophoresis mass spectrometry.

PubMed

Váradi, Csaba; Mittermayr, Stefan; Millán-Martín, Silvia; Bones, Jonathan

2016-12-01

Capillary electrophoresis (CE) offers excellent efficiency and orthogonality to liquid chromatographic (LC) separations for oligosaccharide structural analysis. Combination of CE with high resolution mass spectrometry (MS) for glycan analysis remains a challenging task due to the MS incompatibility of background electrolyte buffers and additives commonly used in offline CE separations. Here, a novel method is presented for the analysis of 2-aminobenzoic acid (2-AA) labelled glycans by capillary electrophoresis coupled to mass spectrometry (CE-MS). To ensure maximum resolution and excellent precision without the requirement for excessive analysis times, CE separation conditions including the concentration and pH of the background electrolyte, the effect of applied pressure on the capillary inlet and the capillary length were evaluated. Using readily available 12/13 C 6 stable isotopologues of 2-AA, the developed method can be applied for quantitative glycan profiling in a twoplex manner based on the generation of extracted ion electropherograms (EIE) for 12 C 6 'light' and 13 C 6 'heavy' 2-AA labelled glycan isotope clusters. The twoplex quantitative CE-MS glycan analysis platform is ideally suited for comparability assessment of biopharmaceuticals, such as monoclonal antibodies, for differential glycomic analysis of clinical material for potential biomarker discovery or for quantitative microheterogeneity analysis of different glycosylation sites within a glycoprotein. Additionally, due to the low injection volume requirements of CE, subsequent LC-MS analysis of the same sample can be performed facilitating the use of orthogonal separation techniques for structural elucidation or verification of quantitative performance.

Electrochemical behavior and voltammetric determination of acetaminophen based on glassy carbon electrodes modified with poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite films.

PubMed

Zhu, Wencai; Huang, Hui; Gao, Xiaochun; Ma, Houyi

2014-12-01

Poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite film modified glassy carbon electrodes (4-ABA/ERGO/GCEs) were fabricated by a two-step electrochemical method. The electrochemical behavior of acetaminophen at the modified electrode was investigated by means of cyclic voltammetry. The results indicated that 4-ABA/ERGO composite films possessed excellent electrocatalytic activity towards the oxidation of acetaminophen. The electrochemical reaction of acetaminophen at 4-ABA/ERGO/GCE is proved to be a surface-controlled process involving the same number of protons and electrons. The voltammetric determination of acetaminophen performed with the 4-ABA/ERGO modified electrode presents a good linearity in the range of 0.1-65 μM with a low detection limit of 0.01 μM (S/N=3). In the case of using the 4-ABA/ERGO/GCE, acetaminophen and dopamine can be simultaneously determined without mutual interference. Furthermore, the 4-ABA/ERGO/GCE has good reproducibility and stability, and can be used to determine acetaminophen in tablets. Copyright © 2014 Elsevier B.V. All rights reserved.

Description of strain 3CB-1, a genomovar of Thauera aromatica, capable of degrading 3-chlorobenzoate coupled to nitrate reduction.

PubMed

Song, B; Palleroni, N J; Häggblom, M M

2000-03-01

A Gram-negative bacterium, strain 3CB-1, isolated from a 3-chlorobenzoate enrichment culture inoculated with a sediment sample is capable of degrading various aromatic compounds and halogenated derivatives with nitrate as electron acceptor. Compounds capable of serving as carbon and energy sources include 3-chlorobenzoate, 3-bromobenzoate, 2-fluorobenzoate, 4-fluorobenzoate, benzoate, 3-hydroxybenzoate, 4-hydroxybenzoate, 3-aminobenzoate, protocatechuate, m-cresol and p-cresol. Oxygen, nitrate and nitrite were used as electron acceptors for growth. Cells are Gram-negative short rods with peritrichous flagellation. The predominant fatty acids are cis-9-hexadecenoic acid (16:1 omega 7c), hexadecanoic acid (16:0), octadecanoic acid (18:0), octadecenoic acid (18:1), 3-hydroxydecanoic acid (10:0 3OH) and dodecanoic acid (12:0). The sequence of the 16S rRNA gene, as well as the fatty acid composition, indicate that the strain is a member of the genus Thauera in the beta-subclass of the Proteobacteria and very close to Thauera aromatica. DNA-DNA hybridization and nutrient screening indicate that strain 3CB-1 is a genomovar of Thauera aromatica with the proposed name Thauera aromatica genomovar chlorobenzoica.

A polymer supported Cu(I) catalyst for the 'click reaction' in aqueous media.

PubMed

Ul Islam, Rafique; Taher, Abu; Choudhary, Meenakshi; Witcomb, Michael J; Mallick, Kaushik

2015-01-21

Polymer stabilized monovalent copper has been synthesized using an in situ chemical transformation route and was characterized by means of different microscopic, optical and surface characterization techniques, which offered information about the chemical structure of the polymer and the morphology of the complex. The supramolecular material, Cu(i)-poly(2-aminobenzoic acid), denoted Cu(i)-pABA, showed catalytic activity for the cycloaddition reaction between terminal alkynes and azides to synthesize 1,2,3-triazoles with excellent yields. The catalyst was recovered from the reaction mixture and recycled several times without an appreciable loss of catalytic activity. The whole strategy was done under ambient conditions and in the presence of water as a solvent.

Directed amination of non-acidic arene C-H bonds by a copper-silver catalytic system.

PubMed

Tran, Ly Dieu; Roane, James; Daugulis, Olafs

2013-06-03

Amine meets arene: A method for direct amination of β-C(sp(2))-H bonds of benzoic acid derivatives and γ-C(sp(2))-H bonds of benzylamine derivatives has been developed. The reaction is catalyzed by Cu(OAc)2 and a Ag2CO3 cocatalyst, and shows high generality and functional-group tolerance, as well as providing a straightforward means for the preparation of ortho-aminobenzoic acid derivatives. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Highly Stereocontrolled, One-Pot Approach toward Pyrrolobenzoxazinones and Pyrroloquinazolinones through a Lewis Acid-Catalyzed [3 + 2]-Cycloannulation Process.

PubMed

Boomhoff, Michael; Ukis, Rostyslav; Schneider, Christoph

2015-08-21

We report herein a stereocontrolled [3 + 2]-cycloheteroannulation of bis-silyl dienediolate 1 with 2-aminobenzoic acid- and 2-aminobenzamide-derived imines to furnish highly substituted pyrrolo[1,2-a]benzoxazinones 3 and pyrrolo[1,2-a]quinazolinones 4, respectively, in good overall yields. This one-pot process rapidly generates molecular complexity and comprises a Lewis acid-catalyzed, vinylogous Mannich reaction of 1 followed by an intramolecular N,O-acetal- and N,N-aminal formation, respectively, which proceeds with good to excellent stereocontrol.

Diaquachloro-tris(ethyl-p-Aminobenzoate)copper(II) Chloride: Synthesis, Characterization and In Vitro Investigation of Antibacterial Activity

NASA Astrophysics Data System (ADS)

Rahardjo, S. B.; Lestari, W. W.; Syaima, H.

2017-07-01

The new complex of [Cu(benz)3(H2O)2Cl]Cl has been synthesized in 1:4 mole ratio of CuCl2·2H2O and ethyl-p-aminobenzoate (benz) in ethanol at room temperature. The complex was characterized by UV-Vis and infrared spectroscopy, Atomic Absorption Spectroscopy (AAS), thermal analysis, magnetic measurement and molar conductivity. Infrared spectra indicated that benz was coordinated to the metal ion through nitrogen of primary amine group. Water molecules and chloride ion were also coordinated to Cu(II). CuCl2·2H2O, benz, and Cu(II) complex were screened for investigating in vitro antibacterial activity against Staphylococcus aureus and Escherichia coli using a modified Kirby-Bauer method.

Characterization of inhibitory effects of the potential therapeutic inhibitors, benzoic acid and pyridine derivatives, on the monophenolase and diphenolase activities of tyrosinase.

PubMed

Gheibi, Nematollah; Taherkhani, Negar; Ahmadi, Abolfazl; Haghbeen, Kamahldin; Ilghari, Dariush

2015-02-01

Involvement of tyrosinase in the synthesis of melanin and cell signaling pathway has made it an attractive target in the search for therapeutic inhibitors for treatment of different skin hyperpigmentation disorders and melanoma cancers. In the present study, we conducted a comprehensive kinetic analysis to understand the mechanisms of inhibition imposed by 2-amino benzoic acid, 4-amino benzoic acid, nicotinic acid, and picolinic acid on the monophenolase and diphenolase activities of the mushroom tyrosinase, and then MTT assay was exploited to evaluate their toxicity on the melanoma cells. Kinetic analysis revealed that nicotinic acid and picolinic acid competitively restricted the monophenolase activity with inhibition constants (Ki) of 1.21 mM and 1.97 mM and the diphenolase activity with Kis of 2.4 mM and 2.93 mM, respectively. 2-aminobenzoic acid and 4-aminobenzoic acid inhibited the monophenolase activity in a non-competitive fashion with Kis of 5.15 µM and 3.8 µM and the diphenolase activity with Kis of 4.72 µM and 20 µM, respectively. Our cell-based data revealed that only the pyridine derivatives imposed cytotoxicity in melanoma cells. Importantly, the concentrations of the inhibitors leading to 50% decrease in the cell density (IC50) were comparable to those causing 50% drop in the enzyme activity, implying that the observed cytotoxicity is highly likely due to the tyrosinase inhibition. Moreover, our cell-based data exhibited that the pyridine derivatives acted as anti-proliferative agents, perhaps inducing cytotoxicity in the melanoma cells through inhibition of the tyrosinase activities.

Characterization of inhibitory effects of the potential therapeutic inhibitors, benzoic acid and pyridine derivatives, on the monophenolase and diphenolase activities of tyrosinase

PubMed Central

Gheibi, Nematollah; Taherkhani, Negar; Ahmadi, Abolfazl; Haghbeen, Kamahldin; Ilghari, Dariush

2015-01-01

Objective(s): Involvement of tyrosinase in the synthesis of melanin and cell signaling pathway has made it an attractive target in the search for therapeutic inhibitors for treatment of different skin hyperpigmentation disorders and melanoma cancers. Materials and Methods: In the present study, we conducted a comprehensive kinetic analysis to understand the mechanisms of inhibition imposed by 2-amino benzoic acid, 4-amino benzoic acid, nicotinic acid, and picolinic acid on the monophenolase and diphenolase activities of the mushroom tyrosinase, and then MTT assay was exploited to evaluate their toxicity on the melanoma cells. Results: Kinetic analysis revealed that nicotinic acid and picolinic acid competitively restricted the monophenolase activity with inhibition constants (Ki) of 1.21 mM and 1.97 mM and the diphenolase activity with Kis of 2.4 mM and 2.93 mM, respectively. 2-aminobenzoic acid and 4-aminobenzoic acid inhibited the monophenolase activity in a non-competitive fashion with Kis of 5.15 µM and 3.8 µM and the diphenolase activity with Kis of 4.72 µM and 20 µM, respectively. Conclusion: Our cell-based data revealed that only the pyridine derivatives imposed cytotoxicity in melanoma cells. Importantly, the concentrations of the inhibitors leading to 50% decrease in the cell density (IC50) were comparable to those causing 50% drop in the enzyme activity, implying that the observed cytotoxicity is highly likely due to the tyrosinase inhibition. Moreover, our cell-based data exhibited that the pyridine derivatives acted as anti-proliferative agents, perhaps inducing cytotoxicity in the melanoma cells through inhibition of the tyrosinase activities. PMID:25810885

Dual Modifications Strategy to Quantify Neutral and Sialylated N-Glycans Simultaneously by MALDI-MS

PubMed Central

2015-01-01

Differences in ionization efficiency among neutral and sialylated glycans prevent direct quantitative comparison by their respective mass spectrometric signals. To overcome this challenge, we developed an integrated chemical strategy, Dual Reactions for Analytical Glycomics (DRAG), to quantitatively compare neutral and sialylated glycans simultaneously by MALDI-MS. Initially, two glycan samples to be compared undergo reductive amination with 2-aminobenzoic acid and 2-13[C6]-aminobenzoic acid, respectively. The different isotope-incorporated glycans are then combined and subjected to the methylamidation of the sialic acid residues in one mixture, homogenizing the ionization responses for all neutral and sialylated glycans. By this approach, the expression change of relevant glycans between two samples is proportional to the ratios of doublet signals with a static 6 Da mass difference in MALDI-MS and the change in relative abundance of any glycan within samples can also be determined. The strategy was chemically validated using well-characterized N-glycans from bovine fetuin and IgG from human serum. By comparing the N-glycomes from a first morning (AM) versus an afternoon (PM) urine sample obtained from a single donor, we further demonstrated the ability of DRAG strategy to measure subtle quantitative differences in numerous urinary N-glycans. PMID:24766348

Dual modifications strategy to quantify neutral and sialylated N-glycans simultaneously by MALDI-MS.

PubMed

Zhou, Hui; Warren, Peter G; Froehlich, John W; Lee, Richard S

2014-07-01

Differences in ionization efficiency among neutral and sialylated glycans prevent direct quantitative comparison by their respective mass spectrometric signals. To overcome this challenge, we developed an integrated chemical strategy, Dual Reactions for Analytical Glycomics (DRAG), to quantitatively compare neutral and sialylated glycans simultaneously by MALDI-MS. Initially, two glycan samples to be compared undergo reductive amination with 2-aminobenzoic acid and 2-(13)[C6]-aminobenzoic acid, respectively. The different isotope-incorporated glycans are then combined and subjected to the methylamidation of the sialic acid residues in one mixture, homogenizing the ionization responses for all neutral and sialylated glycans. By this approach, the expression change of relevant glycans between two samples is proportional to the ratios of doublet signals with a static 6 Da mass difference in MALDI-MS and the change in relative abundance of any glycan within samples can also be determined. The strategy was chemically validated using well-characterized N-glycans from bovine fetuin and IgG from human serum. By comparing the N-glycomes from a first morning (AM) versus an afternoon (PM) urine sample obtained from a single donor, we further demonstrated the ability of DRAG strategy to measure subtle quantitative differences in numerous urinary N-glycans.

Diastereoselective cyclization of an aminobenzoic acid derivative and chiroptical properties of triple-stranded helical bis(phenylethynyl)benzene.

PubMed

Yamakado, Ryohei; Matsuoka, Shin-ichi; Suzuki, Masato; Takeuchi, Daisuke; Masu, Hyuma; Azumaya, Isao; Takagi, Koji

2015-04-04

The diastereoselective cyclization of 2,5-dibromo-4-hexylaminobenzoic acid was achieved by the microwave-assisted condensation using SiCl4. Moreover, the triple-stranded helical structure of bis(phenylethynyl)benzene units embedded in the cyclic tri(benzamide) scaffold was obtained by a Sonogashira-Hagihara coupling reaction. Two optically active enantiomers that do not racemize even at the elevated temperature were separated by chiral HPLC. The chiral helical topology was revealed by the spectroscopic data and theoretical calculation.

Mathematical evaluation of the amino acid and polyphenol content and antioxidant activities of fruits from different apricot cultivars.

PubMed

Sochor, Jiri; Skutkova, Helena; Babula, Petr; Zitka, Ondrej; Cernei, Natalia; Rop, Otakar; Krska, Boris; Adam, Vojtech; Provazník, Ivo; Kizek, Rene

2011-09-01

Functional foods are of interest because of their significant effects on human health, which can be connected with the presence of some biologically important compounds. In this study, we carried out complex analysis of 239 apricot cultivars (Prunus armeniaca L.) cultivated in Lednice (climatic area T4), South Moravia, Czech Republic. Almost all previously published studies have focused only on analysis of certain parameters. However, we focused on detection both primary and secondary metabolites in a selection of apricot cultivars with respect to their biological activity. The contents of thirteen biogenic alpha-L-amino acids (arginine, asparagine, isoleucine, lysine, serine, threonine, valine, leucine, phenylalanine, tryptophan, tyrosine, proline and alanine) were determined using ion exchange chromatography with UV-Vis spectrometry detection. Profile of polyphenols, measured as content of ten polyphenols with significant antioxidant properties (gallic acid, procatechinic acid, p-aminobenzoic acid, chlorogenic acid, caffeic acid, vanillin, p-coumaric acid, rutin, ferrulic acid and quercetrin), was determined by high performance liquid chromatography with spectrometric/electrochemical detection. Moreover, content of total phenolics was determined spectrophotometrically using the Folin-Ciocalteu method. Antioxidant activity was determined using five independent spectrophotometric methods: DPPH assay, DMPD method, ABTS method, FRAP and Free Radicals methods. Considering the complexity of the obtained data, they were processed and correlated using bioinformatics techniques (cluster analysis, principal component analysis). The studied apricot cultivars were clustered according to their common biochemical properties, which has not been done before. The observed similarities and differences were discussed.

Mutasynthesis of fluorinated pactamycin analogues and their antimalarial activity.

PubMed

Almabruk, Khaled H; Lu, Wanli; Li, Yuexin; Abugreen, Mostafa; Kelly, Jane X; Mahmud, Taifo

2013-04-05

A mutasynthetic strategy has been used to generate fluorinated TM-025 and TM-026, two biosynthetically engineered pactamycin analogues produced by Streptomyces pactum ATCC 27456. The fluorinated compounds maintain excellent activity and selectivity toward chloroquine-sensitive and multidrug-resistant strains of malarial parasites as the parent compounds. The results also provide insights into the biosynthesis of 3-aminobenzoic acid in S. pactum.

Discovery of novel inhibitors for DHODH via virtual screening and X-ray crystallographic structures

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

McLean, Larry R.; Zhang, Ying; Degnen, William

2010-10-28

Amino-benzoic acid derivatives 1-4 were found to be inhibitors for DHODH by virtual screening, biochemical, and X-ray crystallographic studies. X-ray structures showed that 1 and 2 bind to DHODH as predicted by virtual screening, but 3 and 4 were found to be structurally different from the corresponding compounds initially identified by virtual screening.

Photocatalytic degradation of sunscreen active ingredients mediated by nanostructured materials

NASA Astrophysics Data System (ADS)

Soto-Vazquez, Loraine

Water scarcity and pollution are environmental issues with terrible consequences. In recent years several pharmaceutical and personal care products, such as sunscreen active ingredients, have been detected in different water matrices. Its recalcitrant behavior in the environment has caused controversies and generated countless questions about its safety. During this research, we employed an advanced oxidation process (photocatalysis) to degrade sunscreen active ingredients. For this study, we used a 3x3 system, evaluating three photocatalysts and three different contaminants. From the three catalysts employed, two of them were synthesized. ZnO nanoparticles were obtained using zinc acetate dihydrated as the precursor, and TiO2 nanowires were synthesized from titanium tetrachloride precursor. The third catalyst employed (namely, P25) was obtained commercially. The synthesized photocatalysts were characterized in terms of the morphology, elemental composition, crystalline structure, elemental oxidation states, vibrational modes and surface area, using SEM-EDS, XRD, XPS, Raman spectroscopy and BET measurements, respectively. The photocatalysts were employed during the study of the degradation of p-aminobenzoic acid, phenylbenzimidazole sulfonic acid, and benzophenone-4. In all the cases, at least 50% degradation was achieved. P25 showed degradation efficiencies above 90%, and from the nine systems, 7 of them degraded at least 86%.

Stabilization of the Nitric Oxide (NO) Prodrugs and Anti-Cancer Leads, PABA/NO and Double JS-K through Incorporation into PEG-Protected Nanoparticles

PubMed Central

Kumar, Varun; Hong, Sam Y.; Maciag, Anna E.; Saavedra, Joseph E.; Adamson, Douglas H.; Prud'homme, Robert K.; Keefer, Larry K.; Chakrapani, Harinath

2009-01-01

Here we report the stabilization of the nitric oxide (NO) prodrugs and anti-cancer lead compounds, PABA/NO (O2-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) and “Double JS-K” (1,5-bis{[1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diol-2-ato]-2,4-dinitrobenzene), through their incorporation into polymer-protected nanoparticles. The prodrugs were formulated in block copolymer-stabilized nanoparticles with sizes from 220 to 450 nm by a novel rapid precipitation process. The block copolymers, with polyethylene glycol (PEG) soluble blocks, provide a steric barrier against NO prodrug activation by glutathione. Too rapid activation and NO release has been a major barrier to effective administration of this class of compounds. The nanoparticle stabilized PABA/NO from attack by glutathione as evidenced by a significant increase in time taken for 50% decomposition from 15 min (unformulated) to 5 h (formulated); in the case of Double JS-K, the 50% decomposition time was extended from 4.5 min (unformulated) to 40 min (formulated). The more hydrophobic PABA/NO produced more stable nanoparticles and correspondingly more extended release times in comparison with Double JS-K. The hydrophobic blocks of the polymer were either polystyrene or polylactide. Both blocks produced nanoparticles of approximately the same size and release kinetics. This combination of PEG-protected nanoparticles with sizes appropriate for cancer targeting by enhanced permeation and retention (EPR) and delayed release of NO may afford enhanced therapeutic benefit. PMID:20000791

Stabilization of the nitric oxide (NO) prodrugs and anticancer leads, PABA/NO and Double JS-K, through incorporation into PEG-protected nanoparticles.

PubMed

Kumar, Varun; Hong, Sam Y; Maciag, Anna E; Saavedra, Joseph E; Adamson, Douglas H; Prud'homme, Robert K; Keefer, Larry K; Chakrapani, Harinath

2010-02-01

We report the stabilization of the nitric oxide (NO) prodrugs and anticancer lead compounds, PABA/NO (O(2)-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) and "Double JS-K" 1,5-bis-{1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diol-2-ato}-2,4-dinitrobenzene, through their incorporation into polymer-protected nanoparticles. The prodrugs were formulated in block copolymer-stabilized nanoparticles with sizes from 220 to 450 nm by a novel rapid precipitation process. The block copolymers, with polyethylene glycol (PEG) soluble blocks, provide a steric barrier against NO prodrug activation by glutathione. Too rapid activation and NO release has been a major barrier to effective administration of this class of compounds. The nanoparticle stabilized PABA/NO are protected from attack by glutathione as evidenced by a significant increase in time taken for 50% decomposition from 15 min (unformulated) to 5 h (formulated); in the case of Double JS-K, the 50% decomposition time was extended from 4.5 min (unformulated) to 40 min (formulated). The more hydrophobic PABA/NO produced more stable nanoparticles and correspondingly more extended release times in comparison with Double JS-K. The hydrophobic blocks of the polymer were either polystyrene or polylactide. Both blocks produced nanoparticles of approximately the same size and release kinetics. This combination of PEG-protected nanoparticles with sizes appropriate for cancer targeting by enhanced permeation and retention (EPR) and delayed release of NO may afford enhanced therapeutic benefit.

Three pharmaceuticals cocrystals of adefovir: Syntheses, structures and dissolution study

NASA Astrophysics Data System (ADS)

Zhang, Xiaoming; Sun, Fuxing; Zhang, Tingting; Jia, Jiangtao; Su, Hongmin; Wang, Chenhui; Zhu, Guangshan

2015-11-01

We report here three novel cocrystals, which are composed of adefovir as the API (Active Pharmaceutical Ingredient) with p-aminobenzoic acid (1, 2C8H12N5O4P·C7H6NO2·3H2O), 3,5-dihydroxybenzoic acid (2, C8H12N5O4P·C7H6O4·H2O) and 2,6-pyridinedicarboxlic acid (3, C8H12N5O4P·C7H5NO4) as CCFs (cocrystal formers) respectively by crystal engineering strategy. Their structures were characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD) analysis, thermogravimetric analyses (TGA), elemental analysis (EA) and infrared spectral analysis (IR). The analysis of single crystal X-ray diffraction demonstrate that cocrystal 1 and 2 form a strong hydrogen-bonded assembly through the phosphoric acids of API with water in the lattice and carboxylic acids of CCF respectively. Cocrystal 3 is formed in which the phosphoric acid groups of API are also held by the carboxylic acid groups of CCF. The PXRD results indicate their high purity of as-synthesized samples. The TGA, EA, IR and dissolution study of API and the cocrystals were also measured and discussed.

Reversible modulation of the redox activity in conducting polymer nanofilms induced by hydrophobic collapse of a surface-grafted polyelectrolyte.

PubMed

Fenoy, Gonzalo E; Giussi, Juan M; von Bilderling, Catalina; Maza, Eliana M; Pietrasanta, Lía I; Knoll, Wolfgang; Marmisollé, Waldemar A; Azzaroni, Omar

2018-05-15

We present the covalent modification of a Pani-like conducting polymer (polyaminobenzylamine, PABA) by grafting of a polyelectrolyte brush (poly [2-(methacryloyloxy)-ethyl-trimethylammonium chloride], PMETAC). As PABA has extra pendant amino moieties, the grafting procedure does not affect the backbone nitrogen atoms that are implicated in the electronic structure of the conducting polymers. Moreover, perchlorate anions interact very strongly with the quaternary ammonium pendant groups of PMETAC through ion pairing. Therefore, the grafting does not only keep the electroactivity of PABA in aqueous solutions but it adds the ion-actuation properties of the PMETAC brush to the modified electrode as demonstrated by contact angle measurements and electrochemical methods. In this way, the conjugation of the electron transfer properties of the conducting polymer with the anion responsiveness of the integrated brush renders perchlorate actuation of the electrochemical response. These results constitute a rational integration of nanometer-sized polymer building blocks that yields synergism of functionalities and illustrate the potentialities of nanoarchitectonics for pushing the limits of soft material science into the nanoworld. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparative analysis of monoclonal antibody N-glycosylation using stable isotope labelling and UPLC-fluorescence-MS.

PubMed

Millán Martín, Silvia; Delporte, Cédric; Farrell, Amy; Navas Iglesias, Natalia; McLoughlin, Niaobh; Bones, Jonathan

2015-03-07

A twoplex method using (12)C6 and (13)C6 stable isotope analogues (Δmass = 6 Da) of 2-aminobenzoic acid (2-AA) is described for quantitative analysis of N-glycans present on monoclonal antibodies and other glycoproteins using ultra performance liquid chromatography with sequential fluorescence and accurate mass tandem quadrupole time of flight (QToF) mass spectrometric detection.

Utilization of Boron Compounds for the Modification of Suberoyl Anilide Hydroxamic Acid as Inhibitor of Histone Deacetylase Class II Homo sapiens

PubMed Central

Bakri, Ridla; Parikesit, Arli Aditya; Satriyanto, Cipta Prio; Kerami, Djati; Tambunan, Usman Sumo Friend

2014-01-01

Histone deacetylase (HDAC) has a critical function in regulating gene expression. The inhibition of HDAC has developed as an interesting anticancer research area that targets biological processes such as cell cycle, apoptosis, and cell differentiation. In this study, an HDAC inhibitor that is available commercially, suberoyl anilide hydroxamic acid (SAHA), has been modified to improve its efficacy and reduce the side effects of the compound. Hydrophobic cap and zinc-binding group of these compounds were substituted with boron-based compounds, whereas the linker region was substituted with p-aminobenzoic acid. The molecular docking analysis resulted in 8 ligands with ΔG binding value more negative than the standards, SAHA and trichostatin A (TSA). That ligands were analyzed based on the nature of QSAR, pharmacological properties, and ADME-Tox. It is conducted to obtain a potent inhibitor of HDAC class II Homo sapiens. The screening process result gave one best ligand, Nova2 (513246-99-6), which was then further studied by molecular dynamics simulations. PMID:25214833

Data for analysis of mannose-6-phosphate glycans labeled with fluorescent tags

PubMed Central

Kang, Ji-Yeon; Kwon, Ohsuk; Gil, Jin Young; Oh, Doo-Byoung

2016-01-01

Mannose-6-phosphate (M-6-P) glycan plays an important role in lysosomal targeting of most therapeutic enzymes for treatment of lysosomal storage diseases. This article provides data for the analysis of M-6-P glycans by high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The identities of M-6-P glycan peaks in HPLC profile were confirmed by measuring the masses of the collected peak eluates. The performances of three fluorescent tags (2-aminobenzoic acid [2-AA], 2-aminobenzamide [2-AB], and 3-(acetyl-amino)-6-aminoacridine [AA-Ac]) were compared focusing on the analysis of bi-phosphorylated glycan (containing two M-6-Ps). The bi-phosphorylated glycan analysis is highly affected by the attached fluorescent tag and the hydrophilicity of elution solvent used in HPLC. The data in this article is associated with the research article published in “Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans” (Kang et al., 2016 [1]). PMID:27222848

Data for analysis of mannose-6-phosphate glycans labeled with fluorescent tags.

PubMed

Kang, Ji-Yeon; Kwon, Ohsuk; Gil, Jin Young; Oh, Doo-Byoung

2016-06-01

Mannose-6-phosphate (M-6-P) glycan plays an important role in lysosomal targeting of most therapeutic enzymes for treatment of lysosomal storage diseases. This article provides data for the analysis of M-6-P glycans by high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The identities of M-6-P glycan peaks in HPLC profile were confirmed by measuring the masses of the collected peak eluates. The performances of three fluorescent tags (2-aminobenzoic acid [2-AA], 2-aminobenzamide [2-AB], and 3-(acetyl-amino)-6-aminoacridine [AA-Ac]) were compared focusing on the analysis of bi-phosphorylated glycan (containing two M-6-Ps). The bi-phosphorylated glycan analysis is highly affected by the attached fluorescent tag and the hydrophilicity of elution solvent used in HPLC. The data in this article is associated with the research article published in "Comparison of fluorescent tags for analysis of mannose-6-phosphate glycans" (Kang et al., 2016 [1]).

Tautomeric and Microscopic Protonation Equilibria of Anthranilic Acid and Its Derivatives.

PubMed

Zapała, Lidia; Woźnicka, Elżbieta; Kalembkiewicz, Jan

2014-01-01

The acid-base chemistry of three zwitterionic compounds, namely anthranilic (2-aminobenzoic acid), N -methylanthranilic and N -phenylanthranilic acid has been characterized in terms of the macroconstants K a1 , K a2 , the isoelectric point p H I , the tautomerization constant K z and microconstants k 11 , k 12 , k 21 , k 22 . The potentiometric titration method was used to determine the macrodissociation constants. Due to the very poor water solubility of N -phenylanthranilic acid the dissociation constants p K a1 and p K a2 were determined in MDM-water mixtures [MDM is a co-solvent mixture, consisting of equal volumes of methanol (MeOH), dioxane and acetonitrile (MeCN)]. The Yasuda-Shedlovsky extrapolation procedure has been used to obtain the values of p K a1 and p K a2 in aqueous solutions. The p K a1 and p K a2 values obtained by this method are 2.86 ± 0.01 and 4.69 ± 0.03, respectively. The tautomerization constant K z describing the equilibrium between unionized form ⇌ zwitterionic form was evaluated by the K z method based on UV-VIS spectrometry. The method uses spectral differences between the zwitterionic form (found at isoelectric pH in aqueous solution) and the unionized form (formed in an organic solvent of low dielectric constant). The highest value of the K z constant has been observed in the case of N -methylantranilic acid (log 10 K z  = 1.31 ± 0.04). The values of log 10 K z for anthranilic and N -phenylanthranilic acids are similar and have values of 0.93 ± 0.03 and 0.90 ± 0.05, respectively. The results indicate that the tested compounds, in aqueous solution around the isoelectric point pH I , occur mainly in the zwitterionic form. Moreover, the influence of the type of substituent and pH of the aqueous phase on the equilibrium were analyzed with regard to the formation and the coexistence of different forms of the acids in the examined systems.

Combined mutagenesis of Rhodosporidium toruloides for improved production of carotenoids and lipids.

PubMed

Zhang, Chaolei; Shen, Hongwei; Zhang, Xibin; Yu, Xue; Wang, Han; Xiao, Shan; Wang, Jihui; Zhao, Zongbao K

2016-10-01

To improve production of lipids and carotenoids by the oleaginous yeast Rhodosporidium toruloides by screening mutant strains. Upon physical mutagenesis of the haploid strain R. toruloides np11 with an atmospheric and room temperature plasma method followed by chemical mutagenesis with nitrosoguanidine, a mutant strain, R. toruloides XR-2, formed dark-red colonies on a screening plate. When cultivated in nitrogen-limited media, XR-2 cells grew slower but accumulated 0.23 g lipids/g cell dry wt and 0.75 mg carotenoids/g CDW. To improve its production capacity, different amino acids and vitamins were supplemented. p-Aminobenzoic acid and tryptophan had beneficial effects on cell growth. When cultivated in nitrogen-limited media in the presence of selected vitamins, XR-2 accumulated 0.41 g lipids/g CDW and 0.69 mg carotenoids/g CDW. A mutant R. toruloides strain with improved production profiles for lipids and carotenoids was obtained, indicating its potential to use combined mutagenesis for a more productive phenotype.

Degradation of N-heterocyclic indole by a novel endophytic fungus Phomopsis liquidambari.

PubMed

Chen, Yan; Xie, Xing-Guang; Ren, Cheng-Gang; Dai, Chuan-Chao

2013-02-01

A broad-spectrum endophytic Phomopsis liquidambari, was used to degrade environmental pollutant indole. In the condition of using indole as sole carbon and nitrogen source, the optimum concentration of indole supplied was determined to be 100 mg L(-1), with 41.7% ratio of indole degradation within 120 h. Exogenous addition of plant litter significantly increased indole degradation to 99.1% within 60 h. Indole oxidation to oxindole and isatin were the key steps limiting indole degradation. Plant litter addition induced fungus to produce laccase and LiP to non-specific oxidize indole. The results of fungal metabolites pathway through HPLC-MS and NMR analysis showed that indole was firstly oxidized to oxindole and isatin, and deoxidated to indolenie-2-dione, then hydroxylated to 2-dioxindole, which pyridine ring were cleaved through C-N position and changed to 2-aminobenzoic acid. Such metabolic pathway was similar with bacterial degradation of indole-3-acetic acid in plant. Copyright © 2012 Elsevier Ltd. All rights reserved.

Synthesis of some 1,8-dioxoacridine carboxylic acid derivatives and the determination of their ionization constants in ethanol-water mixtures

NASA Astrophysics Data System (ADS)

Saygılı, Rukiye; Ulus, Ramazan; Yeşildağ, İbrahim; Kübra İnal, E.; Kaya, Muharrem; Murat Kalfa, O.; Zeybek, Bülent

2015-03-01

Four novel compounds of 1,8-dioxoacridine carboxylic acid derivatives (4-(3,3,6,6-tetramethyl-1,8-dioxo-9-phenyl-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-cyanophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-hydroxyphenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(2,4-dichlorophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid) were prepared by the reaction of the 4-substitute benzaldehyde (hydrogen, hydroxyl, cyano, and 2,4-dichloro), 4-aminobenzoic acid, and 5,5-dimethylcyclohexane-1,3-dione in the presence of p-dodecylbenzenesulfonic acid. They were characterized by using FT-IR, 1H-NMR, 13C-NMR, GC-MS spectroscopic techniques. The stoichiometric ionization constants of these compounds were determined in ethanol-water mixtures of 50%, 60% and 70% ethanol (v/v) by potentiometric titration method and the ionization constants were calculated with three different ways. The effects of solvent composition and substituent groups on ionization constants of 1,8-dioxoacridine carboxylic acids were also discussed.

PEG-poly(amino acid) block copolymer micelles for tunable drug release.

PubMed

Ponta, Andrei; Bae, Younsoo

2010-11-01

To achieve tunable pH-dependent drug release in tumor tissues. Poly(ethylene glycol)-poly(aspartic acid) [PEG-p(Asp)] containing 12 kDa PEG and pAsp (5, 15, and 35 repeating units) were prepared. Hydrazide linkers with spacers [glycine (Gly) and 4-aminobenzoate (Abz)] were introduced to PEG-p(Asp), followed by drug conjugation [doxorubicin (DOX)]. The block copolymer-drug conjugates were either reconstituted or dialyzed in aqueous solutions to prepare micelles. Drug release patterns were observed under sink conditions at pH 5.0 and 7.4, 37°C, for 48 h. A collection of six block copolymers with different chain lengths and spacers was synthesized. Drug binding yields were 13-43.6%. The polymer-drug conjugates formed <50 nm polymer micelles irrespective of polymer compositions. Gly-introduced polymer micelles showed marginal change in particle size (40 ± 10 nm), while the size of Abz-micelles increased gradually from 10 to 40 nm as the polymer chain lengths increased. Drug release patterns of both Gly and Abz micelles were pH-dependent and tunable. The spacers appear to play a crucial role in controlling drug release and stability of polymer micelles in combination with block copolymer chain lengths. A drug delivery platform for tunable drug release was successfully developed with polymer micelles possessing spacer-modified hydrazone drug-binding linkers.

Study of the Chemical Space of Selected Bacteriostatic Sulfonamides from an Information Theory Point of View.

PubMed

López-Rosa, Sheila; Molina-Espíritu, Moyocoyani; Esquivel, Rodolfo O; Soriano-Correa, Catalina; Dehesa, Jésus S

2016-12-05

The relative structural location of a selected group of 27 sulfonamide-like molecules in a chemical space defined by three information theory quantities (Shannon entropy, Fisher information, and disequilibrium) is discussed. This group is composed of 15 active bacteriostatic molecules, 11 theoretically designed ones, and para-aminobenzoic acid. This endeavor allows molecules that share common chemical properties through the molecular backbone, but with significant differences in the identity of the chemical substituents, which might result in bacteriostatic activity, to be structurally classified and characterized. This is performed by quantifying the structural changes on the electron density distribution due to different functional groups and number of electrons. The macroscopic molecular features are described by means of the entropy-like notions of spatial electronic delocalization, order, and uniformity. Hence, an information theory three-dimensional space (IT-3D) emerges that allows molecules with common properties to be gathered. This space witnesses the biological activity of the sulfonamides. Some structural aspects and information theory properties can be associated, as a result of the IT-3D chemical space, with the bacteriostatic activity of these molecules. Most interesting is that the active bacteriostatic molecules are more similar to para-aminobenzoic acid than to the theoretically designed analogues. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crystal structures of palladium(II) ternary complexes of 5-x-2-aminobenzoic acid with 1,10-phenanthroline and their interaction with calf thymus DNA (where X=Cl, Br and I).

PubMed

Wang, Yue; Okabe, Nobuo; Odoko, Mamiko

2005-10-01

The crystal structures of a series of three palladium(II) ternary complexes of 5-halogeno-2-aminobenzoic acid (5-X-AB, where X=Cl, Br and I) with 1,10-phenanthroline [Pd(5-Cl-AB)(phen)] (1), [Pd(5-Br-AB)(phen)] (2) and [Pd(5-I-AB)(phen)] (3) have been determined, and their coordination geometries and the crystal architecture characterized. All of the complexes are an isostructure in which each Pd(II) atom has basically similar square planar coordination geometry. The substitute halogen group at 5-position of AB plays an important role in producing the coordination bonds of the carboxylate and amino groups in which the carboxylate O atom and the amino N atom act as the negative monodentate ligand atoms. The coordination bond distances of O-Pd increase in the order 1<2<3, while those of N-Pd decrease in the same order. The binding of the complexes to the calf thymus DNA has also been studied by the fluorescence method. Each of the complexes shows high binding propensity to DNA which can be reflected as the relative order 1<2<3.

Quantum chemical calculations and experimental investigations on 2-aminobenzoic acid-cyclodiphosph(V)azane derivative and its homo-binuclear Cu(II) complex

NASA Astrophysics Data System (ADS)

El-Gogary, Tarek M.; Alaghaz, Abdel-Nasser M. A.; Ammar, Reda A. A.

2012-03-01

A novel 2-aminobenzoic acid-cyclodiphosph(V)azane ligand H4L and its homo-binuclear Cu(II) complex of the type [Cu2L(H2O)2].2.5 H2O in which L is 1,3-di(-o-pyridyl)-2,4-(dioxo)-2',4'-bis-(2-iminobenzoic acid) cyclodiphosph(V)azane, were synthesized and characterized by different physical techniques. Infrared spectra of the complex indicate deprotonation and coordination of the imine NH and carboxyl COOH groups. It also confirms that nitrogen atom of the pyridine ring contribute to the complexation. Electronic spectra and magnetic susceptibility measurements reveal square-planar geometry for the Cu(II) complex. The elemental analyses and thermogravimetric results have justified the [Cu2L(H2O)2]·2.5H2O composition of the complex. Quantum chemical calculations were utilized to explore the electronic structure and stability of the H4L as well as the binuclear Cu(II) complex. Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of H4L and its binuclear Cu(II) complex. Different tautomers and geometrical isomers of the ligand were optimized at the ab initio DFT level. Simulated IR frequencies were scaled and compared with that experimentally measured. TD-DFT method was used to compute the UV-VIS spectra which show good agreement with measured electronic spectra.

Bis[2-(2-pyridylmethyl­eneamino)benzene­sulfonato-κ3 N,N′,O]cobalt(II) dihydrate

PubMed Central

Huang, Xue-Ren; Ou-Yang, Miao; Yang, Ge-Ge; Meng, Xiu-Jin; Jiang, Yi-Min

2009-01-01

The title complex, [Co(C12H9N2O3S)2]·2H2O, has site symmetry 2 with the CoII cation located on a twofold rotation axis. Two tridentate 2-(2-pyridylmethyl­eneamino)benzene­sulfonate (paba) ligands chelate to the CoII cation in a distorted octa­hedral geometry. The pyridine and benzene rings in the paba ligand are oriented at a dihedral angle of 42.86 (13)°. Inter­molecular O—H⋯O and C—H⋯O hydrogen bonding is present in the crystal structure. PMID:21578190

Occurrence of eight UV filters in beaches of Gran Canaria (Canary Islands). An approach to environmental risk assessment.

PubMed

Sánchez Rodríguez, A; Rodrigo Sanz, M; Betancort Rodríguez, J R

2015-07-01

Due to the growing concern about human health effects of ultraviolet (UV) radiation, the use of UV filters has increased in recent decades. Unfortunately, some common UV filters are bioaccumulated in aquatic organisms and show a potential for estrogenic activity. The aim of the present study is to determine the presence of some UV filters in the coastal waters of six beaches around Gran Canaria Island as consequence of recreational seaside activities. Eight commonly used UV filters: benzophenone-3 (BP-3), octocrylene (OC), octyl-dimethyl-PABA (OD-PABA), ethylhexyl methoxy cinnamate (EHMC), homosalate (HMS), butyl methoxydibenzoyl methane (BMDBM), 4-methylbenzylidene camphor (4-MBC) and diethylamino hydroxybenzoyl hexyl benzoate (DHHB), were monitored and, with the exception of OD-PABA, all were detected in the samples collected. 99% of the samples showed some UV filters and concentration levels reached up to 3316.7 ng/L for BP-3. Environmental risk assessment (ERA) approach showed risk quotients (RQ) higher than 10, which means that there is a significant potential for adverse effects, for 4-MBC and EHMC for those samples with highest levels of UV filters. Copyright © 2015 Elsevier Ltd. All rights reserved.

A novel approach to isoindolo[2,1-a]indol-6-ones.

PubMed

Duncanson, Philip; Cheong, Yuen-Ki; Motevalli, Majid; Griffiths, D Vaughan

2012-06-07

A convenient route to isoindolo[2,1-a]indol-6-ones has been developed starting from the appropriate 2-(N-phthaloyl)benzoic acids. Formation of the acid chlorides with thionyl chloride followed by heating with triethyl phosphite in a suitable solvent resulted in a multistep reaction giving tetracyclic β-ketophosphonates that on reduction with sodium borohydride gave the required indolones in good overall yields. Analogous β-ketophosphonates were also prepared starting with N,N-(1,8-naphthaloyl)-2-aminobenzoic acid and 2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzoic acids although of these only the naphthaloyl product could be reduced with sodium borohydride without cleaving the amide bond in the ring system.

Draft genome sequence of the marine bacterium Streptomyces griseoaurantiacus M045, which produces novel manumycin-type antibiotics with a pABA core component.

PubMed

Li, Fuchao; Jiang, Peng; Zheng, Huajun; Wang, Shengyue; Zhao, Guoping; Qin, Song; Liu, Zhaopu

2011-07-01

Streptomyces griseoaurantiacus M045, isolated from marine sediment, produces manumycin and chinikomycin antibiotics. Here we present a high-quality draft genome sequence of S. griseoaurantiacus M045, the first marine Streptomyces species to be sequenced and annotated. The genome encodes several gene clusters for biosynthesis of secondary metabolites and has provided insight into genomic islands linking secondary metabolism to functional adaptation in marine S. griseoaurantiacus M045.

Compendium of the FY1990 and FY1992 Research Reviews for the Research Methods Branch

DTIC Science & Technology

1994-09-01

the perfusion technique, the perfusion was not done in situ. Trout were anesthetized with MS-222 (3-aminobenzoic acid ethyl ester, Sigma Chemical...by a trypan blue exclusion test. Medaka Medaka were anesthetized with MS-222, transferred to a dissecting tray, and incised from the urogenital pore...Histology General histology was compared at intervals of 20 days. Fish were anesthetized , fixed, and processed for paraffin embedment, and sections

Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

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

Cursino, Ana Cristina Trindade, E-mail: anacursino@ufpr.br; Rives, Vicente, E-mail: vrives@usal.es; Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx

2015-10-15

Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescentmore » materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials.« less

Influence of metabolism in skin on dosimetry after topical exposure

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

Bronaugh, R.L.; Collier, S.W.; Macpherson, S.E.

1994-12-01

Metabolism of chemicals occurs in skin and therefore should be taken into account when one determines topical exposure dose. Skin metabolism is difficult to measure in vivo because biological specimens may also contain metabolites from other tissues. Metabolism in skin during percutaneous absorption can be studied with viable skin in flow-through diffusion cells. Several compounds metabolized by microsomal enzymes in skin (benzo[a]pyrene and 7-ethoxycoumarin) penetrated human and hairless guinea pig skin predominantly unmetabolized. However, compounds containing a primary amino group (p-aminobenzoic acid, benzocaine, and azo color reduction products) were substrates for acetyltransferase activity in skin and were substantially metabolized duringmore » absorption. A physiologically based pharmacokinetic model has been developed with an input equation, allowing modeling after topical exposure. 14 refs., 3 figs., 4 tabs.« less

Effect of ultraviolet light absorbers on photostabilization of azadirachtin-A in solution (part: II).

PubMed

Deota, P T; Upadhyay, P R; Valodkar, V B

2003-01-01

The effect of photostabilization of azadirachtin-A (Aza-A) was examined in solutions when exposed to UV radiation, in the presence of four structurally different UV absorbers namely, p-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered from the solutions after 6 h exposed to UV radiation in the presence and absence of UV absorbers indicated that the order of stabilization of Aza-A by these absorbers was similar to that obtained in the solid phase experiments in accordance with our previous observations. It is observed that the addition of phenyl salicylate in Aza-A (in 1:1 mole ratio) provides the excellent photostabilization of Aza-A molecule in solid phase as well as in solution among the four absorbers studied.

A fluorescence-based method for cyanate analysis in ethanol/water media: correlation between cyanate presence and ethyl carbamate formation in sugar cane spirit.

PubMed

Ohe, Thiago Hideyuki Kobe; da Silva, Alexandre Ataide; Rocha, Thaís da Silva; de Godoy, Flávio Schutzer; Franco, Douglas Wagner

2014-10-01

Based on the fluorescence properties of 2,4-(1H,3H)-quinazolinedione, a product of the reaction between cyanate and 2-aminobenzoic acid, a simple, sensitive, selective, and reproducible method for the cyanate analysis in aqueous ethanolic media is proposed. In this method, λ(exc) and λ(em) are 310 and 410 nm, respectively, and the limits of detection and quantification are 2.2 × 10(-7) and 6.7 × 10(-7) mol/L, respectively. Under optimal conditions (pH = 4.5, 40% ethanol), a concentration of 5.0 × 10(-6) mol/L cyanate can be determined in a single measurement, at a 95% level of confidence, with an uncertainty of ± 0.13 × 10(-6) mol/L. Cyanide, thiocyanate, chloride, nitrate, and sulfate ions, as well as urea and urethane in concentrations 1 × 10(3) higher than that of cyanate do not interfere with the measurement. The methodology was applied to cyanate analyses in the different fractions of the sugarcane distillate and the data strongly suggest a correlation between the presence of urea in wine, and the cyanate and ethyl carbamate concentrations in the spirit. Based on the fluorescence properties of the reaction product between cyanate and 2-aminobenzoic acid, a method for assaying cyanate was devised. This procedure applied to the sugarcane distillate showed for the first time a correlation between cyanate presence and ethyl carbamate (EC) formation in the different fractions of the product. Therefore, the proposed methodology can be used to predict in freshly distillate sugar cane spirits the potential total concentration of EC to be formed. Therefore, these data could be used to advise about the necessity of implementing a procedure to reduce spirit EC concentration before the product reaches the market. © 2014 Institute of Food Technologists®

Synthesis, characterization and evaluation of 1,3,5-triazine aminobenzoic acid derivatives for their antimicrobial activity.

PubMed

Al-Zaydi, Khadijah M; Khalil, Hosam H; El-Faham, Ayman; Khattab, Sherine N

2017-05-10

Replacement of chloride ions in cyanuric chloride give several variants of 1,3,5-triazine derivatives which were investigated as biologically active small molecules. These compounds exhibit antimalarial, antimicrobial, anti-cancer and anti-viral activities, among other beneficial properties. On the other hand, treatment of bacterial infections remains a challenging therapeutic problem because of the emerging infectious diseases and the increasing number of multidrug-resistant microbial pathogens. As multidrug-resistant bacterial strains proliferate, the necessity for effective therapy has stimulated research into the design and synthesis of novel antimicrobial molecules. 1,3,5-Triazine 4-aminobenzoic acid derivatives were prepared by conventional method or by using microwave irradiation. Using microwave irradiation gave the desired products in less time, good yield and higher purity. Esterification of the 4-aminobenzoic acid moiety afforded methyl ester analogues. The s-triazine derivatives and their methyl ester analogues were fully characterized by FT-IR, NMR ( 1 H-NMR and 13 C-NMR), mass spectra and elemental analysis. All the synthesized compounds were evaluated for their antimicrobial activity. Some tested compounds showed promising activity against Staphylococcus aureus and Escherichia coli. Three series of mono-, di- and trisubstituted s-triazine derivatives and their methyl ester analogues were synthesized and fully characterized. All the synthesized compounds were evaluated for their antimicrobial activity. Compounds (10), (16), (25) and (30) have antimicrobial activity against S. aureus comparable to that of ampicillin, while the activity of compound (13) is about 50% of that of ampicillin. Compounds (13) and (14) have antimicrobial activity against E. coli comparable to that of ampicillin, while the activity of compounds (9-12) and (15) is about 50% of that of ampicillin. Furthermore, minimum inhibitory concentrations values for clinical isolates of compounds (10), (13), (14), (16), (25) and (30) were measured. Compounds (10) and (13) were more active against MRSA and E. coli than ampicillin. Invitro cytotoxicity results revealed that compounds (10) and (13) were nontoxic up to 250 µg/mL (with SI = 10) and 125 µg/mL (with SI = 5), respectively. Graphical abstract Three series of mono-, di- and trisubstituted s-triazine derivatives and their methyl ester analogues were synthesized and evaluated for their antimicrobial activity. Several compounds have antimicrobial activity against S. aureus and E. coli comparable to that of ampicillin.

Farnesyltransferase inhibitors: CAAX mimetics based on different biaryl scaffolds.

PubMed

Straniero, Valentina; Pallavicini, Marco; Chiodini, Giuseppe; Ruggeri, Paola; Fumagalli, Laura; Bolchi, Cristiano; Corsini, Alberto; Ferri, Nicola; Ricci, Chiara; Valoti, Ermanno

2014-07-01

Mimetics of the C-terminal CAAX tetrapeptide of Ras protein were designed as farnesyltransferase (FTase) inhibitors (FTIs) by replacing AA with o-aryl or o-heteroaryl substituted p-hydroxy- or p-aminobenzoic acid, while maintaining the replacement of C with 1,4-benzodioxan-2-ylmethyl or 2-amino-4-thiazolylacetyl residue as in previous CAAX mimetics. Both FTase inhibition and antiproliferative effect were showed by two thiazole derivatives, namely those with 1-naphthyl (10 and 10a) or 3-furanyl (15 and 15a) in the central spacer, and by the benzodioxane derivative with 2-thienyl (6 and 6a) in the same position. Accumulation of unprenylated RAS was demonstrated in cells incubated with 15a. Consistently with FTIs literature, such results delineate the biaryl scaffold not only as a spacer but also as a sensible area of these mimetic molecules, where modifications at the branching aromatic ring are not indifferent and should be matter of further investigation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Disaggregation of Amylin Aggregate by Novel Conformationally Restricted Aminobenzoic Acid containing α/β and α/γ Hybrid Peptidomimetics

PubMed Central

Paul, Ashim; Kalita, Sourav; Kalita, Sujan; Sukumar, Piruthivi; Mandal, Bhubaneswar

2017-01-01

Diabetes has emerged as a threat to the current world. More than ninety five per cent of all the diabetic population has type 2 diabetes mellitus (T2DM). Aggregates of Amylin hormone, which is co-secreted with insulin from the pancreatic β-cells, inhibit the activities of insulin and glucagon and cause T2DM. Importance of the conformationally restricted peptides for drug design against T2DM has been invigorated by recent FDA approval of Symlin, which is a large conformationally restricted peptide. However, Symlin still has some issues including solubility, oral bioavailability and cost of preparation. Herein, we introduced a novel strategy for conformationally restricted peptide design adopting a minimalistic approach for cost reduction. We have demonstrated efficient inhibition of amyloid formation of Amylin and its disruption by a novel class of conformationally restricted β-sheet breaker hybrid peptidomimetics (BSBHps). We have inserted β, γ and δ -aminobenzoic acid separately into an amyloidogenic peptide sequence, synthesized α/β, α/γ and α/δ hybrid peptidomimetics, respectively. Interestingly, we observed the aggregation inhibitory efficacy of α/β and α/γ BSBHps, but not of α/δ analogues. They also disrupt existing amyloids into non-toxic forms. Results may be useful for newer drug design against T2DM as well as other amyloidoses and understanding amyloidogenesis. PMID:28054630

Disaggregation of Amylin Aggregate by Novel Conformationally Restricted Aminobenzoic Acid containing α/β and α/γ Hybrid Peptidomimetics

NASA Astrophysics Data System (ADS)

Paul, Ashim; Kalita, Sourav; Kalita, Sujan; Sukumar, Piruthivi; Mandal, Bhubaneswar

2017-01-01

Diabetes has emerged as a threat to the current world. More than ninety five per cent of all the diabetic population has type 2 diabetes mellitus (T2DM). Aggregates of Amylin hormone, which is co-secreted with insulin from the pancreatic β-cells, inhibit the activities of insulin and glucagon and cause T2DM. Importance of the conformationally restricted peptides for drug design against T2DM has been invigorated by recent FDA approval of Symlin, which is a large conformationally restricted peptide. However, Symlin still has some issues including solubility, oral bioavailability and cost of preparation. Herein, we introduced a novel strategy for conformationally restricted peptide design adopting a minimalistic approach for cost reduction. We have demonstrated efficient inhibition of amyloid formation of Amylin and its disruption by a novel class of conformationally restricted β-sheet breaker hybrid peptidomimetics (BSBHps). We have inserted β, γ and δ -aminobenzoic acid separately into an amyloidogenic peptide sequence, synthesized α/β, α/γ and α/δ hybrid peptidomimetics, respectively. Interestingly, we observed the aggregation inhibitory efficacy of α/β and α/γ BSBHps, but not of α/δ analogues. They also disrupt existing amyloids into non-toxic forms. Results may be useful for newer drug design against T2DM as well as other amyloidoses and understanding amyloidogenesis.

Differentiation of isomeric N-glycan structures by normal-phase liquid chromatography-MALDI-TOF/TOF tandem mass spectrometry.

PubMed

Maslen, Sarah; Sadowski, Pawel; Adam, Alex; Lilley, Kathryn; Stephens, Elaine

2006-12-15

The detailed characterization of protein N-glycosylation is very demanding given the many different glycoforms and structural isomers that can exist on glycoproteins. Here we report a fast and sensitive method for the extensive structure elucidation of reducing-end labeled N-glycan mixtures using a combination of capillary normal-phase HPLC coupled off-line to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and TOF/TOF-MS/MS. Using this method, isobaric N-glycans released from honey bee phospholipase A2 and Arabidopsis thaliana glycoproteins were separated by normal-phase chromatography and subsequently identified by key fragment ions in the MALDI-TOF/TOF tandem mass spectra. In addition, linkage and branching information were provided by abundant cross-ring and "elimination" fragment ions in the MALDI-CID spectra that gave extensive structural information. Furthermore, the fragmentation characteristics of N-glycans reductively aminated with 2-aminobenzoic acid and 2-aminobenzamide were compared. The identification of N-glycans containing 3-linked core fucose was facilitated by distinctive ions present only in the MALDI-CID spectra of 2-aminobenzoic acid-labeled oligosaccharides. To our knowledge, this is the first MS/MS-based technique that allows confident identification of N-glycans containing 3-linked core fucose, which is a major allergenic determinant on insect and plant glycoproteins.

Polymer-encapsulated metal nanoparticles: optical, structural, micro-analytical and hydrogenation studies of a composite material.

PubMed

Scalzullo, Stefania; Mondal, Kartick; Witcomb, Mike; Deshmukh, Amit; Scurrell, Mike; Mallick, Kaushik

2008-02-20

A single-step synthesis route is described for the preparation of a metal-polymer composite in which palladium acetate and meta-amino benzoic acid were used as the precursors for palladium nanoparticles and poly(meta-amino benzoic acid) (PABA). The palladium nanoparticles were found to be uniformly dispersed and highly stabilized throughout the macromolecule matrix. The resultant composite material was characterized by means of different techniques, such as IR and Raman spectroscopy, which provided information regarding the chemical structure of the polymer, whereas electron microscopy images yielded information regarding the morphology of the composite material and the distribution of the metal particles in the composite material. The composite material was used as a catalyst for the ethylene hydrogenation reaction and showed catalytic activity at higher temperatures. TEM studies confirmed the changed environment of the nanoparticles at these temperatures.

Condensed, solution and gas phase behaviour of mono- and dinuclear 2,6-diacetylpyridine (dap) hydrazone copper complexes probed by X-ray, mass spectrometry and theoretical calculations.

PubMed

Neto, Brenno A D; Viana, Barbara F L; Rodrigues, Thyago S; Lalli, Priscila M; Eberlin, Marcos N; da Silva, Wender A; de Oliveira, Heibbe C B; Gatto, Claudia C

2013-08-28

We describe the synthesis of novel mononuclear and dinuclear copper complexes and an investigation of their behaviour in solution using mass spectrometry (ESI-MS and ESI-MS/MS) and in the solid state using X-ray crystallography. The complexes were synthesized from two widely used diacetylpryridine (dap) ligands, i.e. 2,6-diacetylpyridinebis(benzoic acid hydrazone) and 2,6-diacetylpyridinebis(2-aminobenzoic acid hydrazone). Theoretical calculations (DFT) were used to predict the complex geometries of these new structures, their equilibrium in solution and energies associated with the transformations.

Grafting of activated carbon cloths for selective adsorption

NASA Astrophysics Data System (ADS)

Gineys, M.; Benoit, R.; Cohaut, N.; Béguin, F.; Delpeux-Ouldriane, S.

2016-05-01

Chemical functionalization of an activated carbon cloth with 3-aminophthalic acid and 4-aminobenzoic acid groups by the in situ formation of the corresponding diazonium salt in aqueous acidic solution is reported. The nature and amount of selected functions on an activated carbon surface, in particular the grafted density, were determined by potentiometric titration, elemental analysis and X-ray photoelectron spectroscopy (XPS). The nanotextural properties of the modified carbon were explored by gas adsorption. Functionalized activated carbon cloth was obtained at a discrete grafting level while preserving interesting textural properties and a large porous volume. Finally, the grafting homogeneity of the carbon surface and the nature of the chemical bonding were investigated using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) technique.

Fabrication of an electrochemical sensor based on computationally designed molecularly imprinted polymer for the determination of mesalamine in real samples.

PubMed

Torkashvand, M; Gholivand, M B; Taherkhani, F

2015-10-01

A novel electrochemical sensor based on mesalamine molecularly imprinted polymer (MIP) film on a glassy carbon electrode was fabricated. Density functional theory (DFT) in gas and solution phases was developed to study the intermolecular interactions in the pre-polymerization mixture and to find the suitable functional monomers in MIP preparation. On the basis of computational results, o-phenylenediamine (OP), gallic acid (GA) and p-aminobenzoic acid (ABA) were selected as functional monomers. The MIP film was cast on glassy carbon electrode by electropolymerization of solution containing ternary monomers and then followed by Ag dendrites (AgDs) with nanobranch deposition. The surface feature of the modified electrode (AgDs/MIP/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Under the optimal experimental conditions, the peak current was proportional to the concentration of mesalamine ranging from 0.05 to 100 μM, with the detection limit of 0.015 μM. The proposed sensor was applied successfully for mesalamine determination in real samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Microbial transformation of nitroaromatic compounds in sewage effluent.

PubMed

Hallas, L E; Alexander, M

1983-04-01

The transformation of mono- and dinitroaromatic compounds was measured in sewage effluent maintained under aerobic or anaerobic conditions. Most of the nitrobenzene, 3- and 4-nitrobenzoic acids, and 3- and 4-nitrotoluenes and much of the 1,2- and 1,3-dinitrobenzenes disappeared both in the presence and absence of oxygen. Under anaerobiosis, 2,6-dinitrotoluene and 3,5-dinitrobenzoic acid disappeared slowly, but no loss was evident in 28 days in aerated sewage. Aromatic amines did not accumulate during the aerobic decomposition of the mononitro compounds. They did appear in nonsterile, but not in sterile, sewage incubated aerobically with the dinitro compounds and anaerobically with all the chemicals. Analysis by gas chromatography and combined gas chromatography-mass spectrometry showed that aniline was formed from nitrobenzene, toluidine was formed from 3- and 4-nitrotoluenes, and aminobenzoic acid was formed from 3- and 4-nitrobenzoic acids under anaerobiosis, and that nitroaniline was formed from 1,2- and 1,3-dinitrobenzenes, aminonitrotoluene resulted from 2,6-dinitrotoluene, and aminonitrobenzoic acid was a product of 3,5-dinitrobenzoic acid under both conditions. The isomeric forms of the metabolites were not established. Aniline, 4-toluidine, and 4-aminobenzoic acid added to sewage disappeared from aerated nonsterile, but not from sterile, sewage or sewage in the absence of oxygen. 2-Nitroaniline, 2-amino-3-nitrotoluene, and 2-amino-5-nitrobenzoic acid added to sewage persisted for at least 60 days in aerobic or anaerobic conditions. Gas chromatographic and gas chromatographic-mass spectrometric analyses demonstrated that acetanilide and 2-methylquinoline were formed from aniline, 4-methylformanilide and 4-methylacetanilide were formed from 4-toluidine, 2-methylbenzimidazole was a product of 2-nitroaniline, and unidentified benzimidazoles were formed from 2-amino-3-nitrotoluene in the absence of oxygen, and that 2-nitroacetanilide and 2-methyl-6-nitroacetanilide were formed from 2-nitroaniline and 2-amino-3-nitrotoluene, respectively, in the presence or absence of oxygen. It is suggested that the transformations of widely used nitroaromatic compounds should be further studied because of the persistence and possible toxicity of products of their metabolism.

Microbial Transformation of Nitroaromatic Compounds in Sewage Effluent

PubMed Central

Hallas, Laurence E.; Alexander, Martin

1983-01-01

The transformation of mono- and dinitroaromatic compounds was measured in sewage effluent maintained under aerobic or anaerobic conditions. Most of the nitrobenzene, 3- and 4-nitrobenzoic acids, and 3- and 4-nitrotoluenes and much of the 1,2- and 1,3-dinitrobenzenes disappeared both in the presence and absence of oxygen. Under anaerobiosis, 2,6-dinitrotoluene and 3,5-dinitrobenzoic acid disappeared slowly, but no loss was evident in 28 days in aerated sewage. Aromatic amines did not accumulate during the aerobic decomposition of the mononitro compounds. They did appear in nonsterile, but not in sterile, sewage incubated aerobically with the dinitro compounds and anaerobically with all the chemicals. Analysis by gas chromatography and combined gas chromatography-mass spectrometry showed that aniline was formed from nitrobenzene, toluidine was formed from 3- and 4-nitrotoluenes, and aminobenzoic acid was formed from 3- and 4-nitrobenzoic acids under anaerobiosis, and that nitroaniline was formed from 1,2- and 1,3-dinitrobenzenes, aminonitrotoluene resulted from 2,6-dinitrotoluene, and aminonitrobenzoic acid was a product of 3,5-dinitrobenzoic acid under both conditions. The isomeric forms of the metabolites were not established. Aniline, 4-toluidine, and 4-aminobenzoic acid added to sewage disappeared from aerated nonsterile, but not from sterile, sewage or sewage in the absence of oxygen. 2-Nitroaniline, 2-amino-3-nitrotoluene, and 2-amino-5-nitrobenzoic acid added to sewage persisted for at least 60 days in aerobic or anaerobic conditions. Gas chromatographic and gas chromatographic-mass spectrometric analyses demonstrated that acetanilide and 2-methylquinoline were formed from aniline, 4-methylformanilide and 4-methylacetanilide were formed from 4-toluidine, 2-methylbenzimidazole was a product of 2-nitroaniline, and unidentified benzimidazoles were formed from 2-amino-3-nitrotoluene in the absence of oxygen, and that 2-nitroacetanilide and 2-methyl-6-nitroacetanilide were formed from 2-nitroaniline and 2-amino-3-nitrotoluene, respectively, in the presence or absence of oxygen. It is suggested that the transformations of widely used nitroaromatic compounds should be further studied because of the persistence and possible toxicity of products of their metabolism. PMID:6859845

Novel metal based anti-tuberculosis agent: synthesis, characterization, catalytic and pharmacological activities of copper complexes.

PubMed

Joseph, J; Nagashri, K; Janaki, G Boomadevi

2012-03-01

Copper complexes of molecular formulae, [CuL(1)(OAc)], [CuL(2)(H(2)O)], [CuL(3)(H(2)O)], [CuL(4)(H(2)O)], [CuL(5)(H(2)O)] where L(1)-L(5) represents Schiff base ligands [by the condensation of 3-hydroxyflavone with 4-aminoantipyrine (L(1))/o-aminophenol (L(2))/o-aminobenzoic acid (L(3))/o-aminothiazole (L(4))/thiosemicarbazide (L(5))], have been prepared. They were characterized using analytical and spectral techniques. The DNA binding properties of copper complexes were studied using electronic absorption spectra and viscosity measurements. Superoxide dismutase and antioxidant activities of the copper complexes have also been studied. Furthermore, the copper complexes have been found to promote pUC18 DNA cleavage in the presence of oxidant. Anti-tuberculosis activity was also performed. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Engineering the Substrate Specificity of the DhbE Adenylation Domain by Yeast Cell Surface Display

PubMed Central

Zhang, Keya; Nelson, Kathryn M.; Bhuripanyo, Karan; Grimes, Kimberly D.; Zhao, Bo; Aldrich, Courtney C.; Yin, Jun

2013-01-01

SUMMARY The adenylation (A) domains of nonribosomal peptide synthetases (NRPSs) activate aryl acids or amino acids to launch their transfer through the NRPS assembly line for the biosynthesis of many medicinally important natural products. In order to expand the substrate pool of NRPSs, we developed a method based on yeast cell surface display to engineer the substrate specificities of the A-domains. We acquired A-domain mutants of DhbE that have 11- and 6-fold increases in kcat/Km with nonnative substrates 3-hydroxybenzoic acid and 2-aminobenzoic acid, respectively and corresponding 3- and 33-fold decreases in kcat/Km values with the native substrate 2,3-dihydroxybenzoic acid, resulting in a dramatic switch in substrate specificity of up to 200-fold. Our study demonstrates that yeast display can be used as a high throughput selection platform to reprogram the “nonribosomal code” of A-domains. PMID:23352143

Investigation of supramolecular synthons and structural characterisation of aminopyridine-carboxylic acid derivatives

PubMed Central

2014-01-01

Background Co-crystal is a structurally homogeneous crystalline material that contains two or more neutral building blocks that are present in definite stoichiometric amounts. The main advantage of co-crystals is their ability to generate a variety of solid forms of a drug that have distinct physicochemical properties from the solid co-crystal components. In the present investigation, five co-crystals containing 2-amino-6-chloropyridine (AMPY) moiety were synthesized and characterized. Results The crystal structure of 2-amino-6-chloropyridine (AMPY) (I), and the robustness of pyridine-acid supramolecular synthon were discussed in four stoichiometry co-crystals of AMPY…BA (II), AMPY…2ABA (III), AMPY…3CLBA (IV) and AMPY…4NBA (V). The abbreviated designations used are benzoic acid (BA), 2-aminobenzoic acid (2ABA), 3-chlorobenzoic acid (3CLBA) and 4-nitrobenzoic acid (4NBA). All the crystalline materials have been characterized by 1HNMR, 13CNMR, IR, photoluminescence, TEM analysis and X-ray diffraction. The supramolecular assembly of each co-crystal is analyzed and discussed. Conclusions Extensive N---H · · · N/N---H · · · O/O---H · · · N hydrogen bonds are found in (I-V), featuring different supramolecular synthons. In the crystal structure, for compound (I), the 2-amino-6-chloropyridine molecules are linked together into centrosymmetric dimers by hydrogen bonds to form homosynthon, whereas for compounds (II-V), the carboxylic group of the respective acids (benzoic acid, 2-aminobenzoic acid, 3-chlorobenzoic acid and 4-nitrobenzoic acid) interacts with pyridine molecule in a linear fashion through a pair of N---H · · · O and O---H · · · N hydrogen bonds, generating cyclic hydrogen-bonded motifs with the graph-set notation R 2 2 8 , to form heterosynthon. In compound (II), another intermolecular N---H · · · O hydrogen bonds further link these heterosynthons into zig-zag chains. Whereas in compounds (IV) and (V), these heterosynthons are centrosymmetrically paired via N---H · · · O hydrogen bonds and each forms a complementary DADA [D = donor and A = acceptor] array of quadruple hydrogen bonds, with graph-set notation R238, R228 and R238. PMID:24887234

Investigation of supramolecular synthons and structural characterisation of aminopyridine-carboxylic acid derivatives.

PubMed

Hemamalini, Madhukar; Loh, Wan-Sin; Quah, Ching Kheng; Fun, Hoong-Kun

2014-01-01

Co-crystal is a structurally homogeneous crystalline material that contains two or more neutral building blocks that are present in definite stoichiometric amounts. The main advantage of co-crystals is their ability to generate a variety of solid forms of a drug that have distinct physicochemical properties from the solid co-crystal components. In the present investigation, five co-crystals containing 2-amino-6-chloropyridine (AMPY) moiety were synthesized and characterized. The crystal structure of 2-amino-6-chloropyridine (AMPY) (I), and the robustness of pyridine-acid supramolecular synthon were discussed in four stoichiometry co-crystals of AMPY…BA (II), AMPY…2ABA (III), AMPY…3CLBA (IV) and AMPY…4NBA (V). The abbreviated designations used are benzoic acid (BA), 2-aminobenzoic acid (2ABA), 3-chlorobenzoic acid (3CLBA) and 4-nitrobenzoic acid (4NBA). All the crystalline materials have been characterized by (1)HNMR, (13)CNMR, IR, photoluminescence, TEM analysis and X-ray diffraction. The supramolecular assembly of each co-crystal is analyzed and discussed. Extensive N---H · · · N/N---H · · · O/O---H · · · N hydrogen bonds are found in (I-V), featuring different supramolecular synthons. In the crystal structure, for compound (I), the 2-amino-6-chloropyridine molecules are linked together into centrosymmetric dimers by hydrogen bonds to form homosynthon, whereas for compounds (II-V), the carboxylic group of the respective acids (benzoic acid, 2-aminobenzoic acid, 3-chlorobenzoic acid and 4-nitrobenzoic acid) interacts with pyridine molecule in a linear fashion through a pair of N---H · · · O and O---H · · · N hydrogen bonds, generating cyclic hydrogen-bonded motifs with the graph-set notation [Formula: see text] , to form heterosynthon. In compound (II), another intermolecular N---H · · · O hydrogen bonds further link these heterosynthons into zig-zag chains. Whereas in compounds (IV) and (V), these heterosynthons are centrosymmetrically paired via N---H · · · O hydrogen bonds and each forms a complementary DADA [D = donor and A = acceptor] array of quadruple hydrogen bonds, with graph-set notation [Formula: see text], [Formula: see text] and [Formula: see text].

UV filters, ethylhexyl methoxycinnamate, octocrylene and ethylhexyl dimethyl PABA from untreated wastewater in sediment from eastern Mediterranean river transition and coastal zones.

PubMed

Amine, Helmieh; Gomez, Elena; Halwani, Jalal; Casellas, Claude; Fenet, Hélène

2012-11-01

UVF may occur in the aquatic environment through two principal sources: direct inputs from recreational activities and indirect wastewater- and river-borne inputs. The aim of this study was to obtain a first overview of levels of three UVF (EHMC, OC and OD-PABA) in coastal areas subjected to river inputs, untreated wastewater discharges and dumpsite leachates. We selected three eastern Mediterranean rivers that have been impacted for decades by untreated wastewater release and collected sediment in the coastal zone during the hot and humid seasons. Western Mediterranean sites receiving treated wastewaters were analyzed for comparison. The results gave an overview of sediment contamination under these two contrasted situations representative of Mediterranean coastal areas without bathing activities. The analysis of the three UVF revealed the ubiquity and high point source contamination by EHMC and OC in transition and coastal zones, with levels as high as 128 ng g(-1)d.w. OD-PABA was also frequently detected, but at lower concentrations (

Simple and Robust N-Glycan Analysis Based on Improved 2-Aminobenzoic Acid Labeling for Recombinant Therapeutic Glycoproteins.

PubMed

Jeong, Yeong Ran; Kim, Sun Young; Park, Young Sam; Lee, Gyun Min

2018-03-21

N-glycans of therapeutic glycoproteins are critical quality attributes that should be monitored throughout all stages of biopharmaceutical development. To reduce both the time for sample preparation and the variations in analytical results, we have developed an N-glycan analysis method that includes improved 2-aminobenzoic acid (2-AA) labeling to easily remove deglycosylated proteins. Using this analytical method, 15 major 2-AA-labeled N-glycans of Enbrel ® were separated into single peaks in hydrophilic interaction chromatography mode and therefore could be quantitated. 2-AA-labeled N-glycans were also highly compatible with in-line quadrupole time-of-flight mass spectrometry (MS) for structural identification. The structures of 15 major and 18 minor N-glycans were identified from their mass values determined by quadrupole time-of-flight MS. Furthermore, the structures of 14 major N-glycans were confirmed by interpreting the MS/MS data of each N-glycan. This analytical method was also successfully applied to neutral N-glycans of Humira ® and highly sialylated N-glycans of NESP ® . Furthermore, the analysis data of Enbrel ® that were accumulated for 2.5 years demonstrated the high-level consistency of this analytical method. Taken together, the results show that a wide repertoire of N-glycans of therapeutic glycoproteins can be analyzed with high efficiency and consistency using the improved 2-AA labeling-based N-glycan analysis method. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Development and validation of a liquid chromatography method for the simultaneous determination of eight water-soluble vitamins in multivitamin formulations and human urine.

PubMed

Patil, Suyog S; Srivastava, Ashwini K

2013-01-01

A simple, precise, and rapid RPLC method has been developed without incorporation of any ion-pair reagent for the simultaneous determination of vitamin C (C) and seven B-complex vitamins, viz, thiamine hydrochloride (B1), pyridoxine hydrochloride (B6), nicotinamide (B3), cyanocobalamine (B12), folic acid, riboflavin (B2), and 4-aminobenzoic acid (Bx). Separations were achieved within 12.0 min at 30 degrees C by gradient elution on an RP C18 column using a mobile phase consisting of a mixture of 15 mM ammonium formate buffer and 0.1% triethylamine adjusted to pH 4.0 with formic acid and acetonitrile. Simultaneous UV detection was performed at 275 and 360 nm. The method was validated for system suitability, LOD, LOQ, linearity, precision, accuracy, specificity, and robustness in accordance with International Conference on Harmonization guidelines. The developed method was implemented successfully for determination of the aforementioned vitamins in pharmaceutical formulations containing an individual vitamin, in their multivitamin combinations, and in human urine samples. The calibration curves for all analytes showed good linearity, with coefficients of correlation higher than 0.9998. Accuracy, intraday repeatability (n = 6), and interday repeatability (n = 7) were found to be satisfactory.

Simultaneous Liquid Chromatographic Determination of 10 Ultra-Violet Filters in Sunscreens.

PubMed

Wharton, Mary; Geary, Michael; O'Connor, Niamh; Curtin, Laura; Ketcher, Krystal

2015-09-01

A rapid HPLC method was developed for the simultaneous determination of 10 UV filters found in sunscreen. The following UV filters were analyzed in this method; 2-phenylbenzimidazole-5-sulfonic acid, benzophenone-3, isoamyl p-methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, ethylhexyl dimethyl 4-aminobenzoic acid, ethylhexyl methoxycinnamate, butyl methoxydibenzoylmethane, ethylhexyl salicylate and homosalate. The method was developed on two columns; a Thermo Hypersil C18 BDS, 3 µm column (4.6 × 100 mm) and a Chromolith RP-18e Monolithic column (4.6 × 100 mm). The same mobile phase of ethanol and 1% acetic acid (70:30, v/v) was employed for both columns. The separation of the 10 UV filters was carried out successfully on both columns; the optimal resolution was obtained on the Thermo Scientific Hypersil column in a time frame of 7 min. An isocratic elution utilizing ethanol and acetic acid (70:30, v/v) at a temperature of 35°C was employed. The method was applied to a number of commercial samples of sunscreen and lotions and was validated according to International Conference on Harmonisation guidelines for selectivity, linearity, accuracy, precision and robustness. A comparison of the performances of both columns was also carried out. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

In silico design, synthesis, and assays of specific substrates for proteinase 3: influence of fluorogenic and charged groups.

PubMed

Narawane, Shailesh; Budnjo, Adnan; Grauffel, Cédric; Haug, Bengt Erik; Reuter, Nathalie

2014-02-13

Neutrophil serine proteases are specific regulators of the immune response, and proteinase 3 is a major target antigen in antineutrophil cytoplasmic antibody-associated vasculitis. FRET peptides containing 2-aminobenzoic acid (Abz) and N-(2,4-dinitrophenyl)ethylenediamine (EDDnp) as fluorophore and quencher groups, respectively, have been widely used to probe proteases specificity. Using in silico design followed by enzymatic assays, we show that Abz and EDDnp significantly contribute to substrate hydrolysis by PR3. We also propose a new substrate specific for PR3.

Synthesis, characterization and biological activity of some transition metals with Schiff base derived from 2-thiophene carboxaldehyde and aminobenzoic acid.

PubMed

Mohamed, Gehad G; Omar, M M; Hindy, Ahmed M M

2005-12-01

Metal complexes of Schiff base derived from 2-thiophene carboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analysis (TGA). The ligand dissociation as well as the metal-ligand stability constants were calculated pH metrically at 25 degrees C and ionic strength mu=0.1 (1M NaCl). The complexes are found to have the formulae [M(HL)2](X)n.yH2O (where M=Fe(III) (X=Cl, n=3, y=3), Co(II) (X=Cl, n=2, y=1.5), Ni(II) (X=Cl, n=2, y=1) and UO2(II) (X=NO3, n=2, y=0)) and [M(L)2] (where M=Cu(II) (X=Cl) and Zn(II) (X=AcO)). The molar conductance data reveal that Fe(III) and Co(II), Ni(II) and UO2(II) chelates are ionic in nature and are of the type 3:1 and 2:1 electrolytes, respectively, while Cu(II) and Zn(II) complexes are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a terdentate manner with ONS donor sites of the carboxylate O, azomethine N and thiophene S. From the magnetic and solid reflectance spectra, it is found that the geometrical structure of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.

Synthesis, characterization and biological activity of some transition metals with Schiff base derived from 2-thiophene carboxaldehyde and aminobenzoic acid

NASA Astrophysics Data System (ADS)

Mohamed, Gehad G.; Omar, M. M.; Hindy, Ahmed M. M.

2005-12-01

Metal complexes of Schiff base derived from 2-thiophene carboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analysis (TGA). The ligand dissociation as well as the metal-ligand stability constants were calculated pH metrically at 25 °C and ionic strength μ = 0.1 (1 M NaCl). The complexes are found to have the formulae [M(HL) 2](X) n· yH 2O (where M = Fe(III) (X = Cl, n = 3, y = 3), Co(II) (X = Cl, n = 2, y = 1.5), Ni(II) (X = Cl, n = 2, y = 1) and UO 2(II) (X = NO 3, n = 2, y = 0)) and [M(L) 2] (where M = Cu(II) (X = Cl) and Zn(II) (X = AcO)). The molar conductance data reveal that Fe(III) and Co(II), Ni(II) and UO 2(II) chelates are ionic in nature and are of the type 3:1 and 2:1 electrolytes, respectively, while Cu(II) and Zn(II) complexes are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a terdentate manner with ONS donor sites of the carboxylate O, azomethine N and thiophene S. From the magnetic and solid reflectance spectra, it is found that the geometrical structure of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, Δ H*, Δ S* and Δ G* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.

Benzoic Acid Derivatives with Trypanocidal Activity: Enzymatic Analysis and Molecular Docking Studies toward Trans-Sialidase.

PubMed

Kashif, Muhammad; Moreno-Herrera, Antonio; Villalobos-Rocha, Juan Carlos; Nogueda-Torres, Benjamín; Pérez-Villanueva, Jaime; Rodríguez-Villar, Karen; Medina-Franco, José Lius; de Andrade, Peterson; Carvalho, Ivone; Rivera, Gildardo

2017-10-30

Chagas, or American trypanosomiasis, remains an important public health problem in developing countries. In the last decade, trans -sialidase has become a pharmacological target for new anti-Chagas drugs. In this work, the aims were to design and find a new series of benzoic acid derivatives as trans -sialidase (TS) inhibitors and anti-trypanosomal agents. Three compounds ( 14 , 18 , and 19 ) sharing a para -aminobenzoic acid moiety showed more potent trypanocidal activity than the commercially available drugs nifurtimox and benznidazole in both strains: the lysis concentration of 50% of the population (LC 50 ) was <0.15 µM on the NINOA strain, and LC 50 < 0.22 µM on the INC-5 strain. Additionally, compound 18 showed a moderate inhibition (47%) on the trans -sialidase enzyme and a binding model similar to DANA (pattern A).

Hydrogen bonding assemblies in host guest complexes with 18-crown-6

NASA Astrophysics Data System (ADS)

Fonari, M. S.; Simonov, Yu. A.; Kravtsov, V. Ch.; Lipkowski, J.; Ganin, E. V.; Yavolovskii, A. A.

2003-02-01

Recent X-ray crystal structural data for two novel 1:2 host-guest complexes of 18-crown-6 with neutral organic molecules, thiaamide hydrazide of 2-aminobenzoic acid and thiaamide hydrazide of 4-amino-1,2,5-thiadiazole-3-carbonic acid are reported. The supramolecular structures of these two and five relative complexes are discussed from the point of view of participation of donor groups in coordination with the crown ether, and donor and acceptor groups in the self-assembly of the guest molecules. Guest molecules have incorporated amine and hydrazine moieties as proton donors and carbonyl oxygen and sulfur (in thiadiazole and in thiaamine moieties) as proton acceptors. The guest-guest interactions appeared to be crucial in the final architecture.

A novel, simple and inexpensive procedure for the simultaneous determination of iopamidol and p-aminohippuric acid for renal function assessment from plasma samples in awake rats.

PubMed

Rodríguez-Romero, Violeta; González-Villalva, Karla I; Reyes, José L; Franco-Bourland, Rebecca E; Guízar-Sahagún, Gabriel; Castañeda-Hernández, Gilberto; Cruz-Antonio, Leticia

2015-03-25

The purpose of the current study was to design, validate and implement a novel analytical method for the simultaneous plasma measurement of iopamidol and p-aminohippuric acid (PAH) to estimate renal function in awake rats. A reverse-phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous measurement of iopamidol (for glomerular filtration rate estimation, GFR) and PAH (for tubular secretion determination, TS) was designed and validated using a C-18 column, 0.1M acetic acid-10% acetonitrile (90:10, v/v) as mobile phase, at a flow rate of 0.3 ml/min, and UV detection at 270 nm. Iopamidol (244.8 mg/kg) was administered intravenously followed immediately by sodium PAH (100 mg/kg) to healthy female Sprague-Dawley rats. Plasma samples obtained at 2.5, 5, 10, 15, 20, 30, 45, 60, 90, and 120 min after drug administration were deproteinized with 2.5% trichloroacetic acid containing p-aminobenzoic acid as internal standard, and separated by the validated RP-HPLC method described above. The iopamidol and PAH chromatographic data were analyzed using a non-compartmental model. The results demonstrated that the RP-HPLC method was linear in ranges between 15-120 μg/ml and 2.5-120 μg/ml for iopamidol and PAH, respectively. Precision and accuracy were within 15% for both drugs. Recovery of iopamidol and PAH was 92% and 100%, respectively. Plasma iopamidol and PAH clearances in awake rats, estimates for GFR and TS, respectively, were 1.49±0.20 ml/min and 3.73±0.38 ml/min. In conclusion, the method here described is a simple and reliable procedure, for the simultaneous and time-saving determination of GFR and TS from plasma samples in the conscious rat. Copyright © 2014 Elsevier B.V. All rights reserved.

De Novo Synthesis of Benzenoid Compounds by the Yeast Hanseniaspora vineae Increases the Flavor Diversity of Wines.

PubMed

Martin, Valentina; Giorello, Facundo; Fariña, Laura; Minteguiaga, Manuel; Salzman, Valentina; Boido, Eduardo; Aguilar, Pablo S; Gaggero, Carina; Dellacassa, Eduardo; Mas, Albert; Carrau, Francisco

2016-06-08

Benzyl alcohol and other benzenoid-derived metabolites of particular importance in plants confer floral and fruity flavors to wines. Among the volatile aroma components in Vitis vinifera grape varieties, benzyl alcohol is present in its free and glycosylated forms. These compounds are considered to originate from grapes only and not from fermentative processes. We have found increased levels of benzyl alcohol in red Tannat wine compared to that in grape juice, suggesting de novo formation of this metabolite during vinification. In this work, we show that benzyl alcohol, benzaldehyde, p-hydroxybenzaldehyde, and p-hydroxybenzyl alcohol are synthesized de novo in the absence of grape-derived precursors by Hanseniaspora vineae. Levels of benzyl alcohol produced by 11 different H. vineae strains were 20-200 times higher than those measured in fermentations with Saccharomyces cerevisiae strains. These results show that H. vineae contributes to flavor diversity by increasing grape variety aroma concentration in a chemically defined medium. Feeding experiments with phenylalanine, tryptophan, tyrosine, p-aminobenzoic acid, and ammonium in an artificial medium were tested to evaluate the effect of these compounds either as precursors or as potential pathway regulators for the formation of benzenoid-derived aromas. Genomic analysis shows that the phenylalanine ammonia-lyase (PAL) and tyrosine ammonia lyase (TAL) pathways, used by plants to generate benzyl alcohols from aromatic amino acids, are absent in the H. vineae genome. Consequently, alternative pathways derived from chorismate with mandelate as an intermediate are discussed.

Potent inhibition of endopeptidase 24.16 and endopeptidase 24.15 by the phosphonamide peptide N-(phenylethylphosphonyl)-Gly-L-Pro-L-aminohexanoic acid.

PubMed Central

Barelli, H; Dive, V; Yiotakis, A; Vincent, J P; Checler, F

1992-01-01

A phosphonamide peptide, N-(phenylethylphosphonyl)-Gly-L-Pro-L-aminohexanoic acid, previously shown to block Clostridium histolyticum collagenases, was examined as a putative inhibitor of endopeptidase 24.16 and endopeptidase 24.15. Hydrolysis of two endopeptidase 24.16 substrates, i.e. 3-carboxy-7-methoxycoumarin (Mcc)-Pro-Leu-Gly-Pro-D-Lys-dinitrophenyl (Dnp) and neurotensin, were completely and dose-dependently inhibited by the phosphonamide inhibitor with KI values of 0.3 and 0.9 nM respectively. In addition, the phosphonamide peptide inhibited the hydrolysis of benzoyl (Bz)-Gly-Ala-Ala-Phe-(pAB) p-aminobenzoate and neurotensin by endopeptidase 24.15 with about a 10-fold lower potency (KI values of 5 and 7.5 nM respectively). The selectivity of this inhibitor towards several exo- and endo-peptidases belonging to the zinc-containing metallopeptidase family established that a 1 microM concentration of this inhibitor was unable to affect leucine aminopeptidase, carboxypeptidase A, angiotensin-converting enzyme and endopeptidase 24.11. The present paper therefore reports on the first hydrophilic highly potent endopeptidase 24.16 inhibitor and describes the most potent inhibitory agent directed towards endopeptidase 24.15 developed to date. These tools should allow one to assess the contribution of endopeptidase 24.16 and endopeptidase 24.15 to the physiological inactivation of neurotensin as well as other neuropeptides. PMID:1332678

Engineering the substrate specificity of the DhbE adenylation domain by yeast cell surface display.

PubMed

Zhang, Keya; Nelson, Kathryn M; Bhuripanyo, Karan; Grimes, Kimberly D; Zhao, Bo; Aldrich, Courtney C; Yin, Jun

2013-01-24

The adenylation (A) domains of nonribosomal peptide synthetases (NRPSs) activate aryl acids or amino acids to launch their transfer through the NRPS assembly line for the biosynthesis of many medicinally important natural products. In order to expand the substrate pool of NRPSs, we developed a method based on yeast cell surface display to engineer the substrate specificities of the A-domains. We acquired A-domain mutants of DhbE that have 11- and 6-fold increases in k(cat)/K(m) with nonnative substrates 3-hydroxybenzoic acid and 2-aminobenzoic acid, respectively and corresponding 3- and 33-fold decreases in k(cat)/K(m) values with the native substrate 2,3-dihydroxybenzoic acid, resulting in a dramatic switch in substrate specificity of up to 200-fold. Our study demonstrates that yeast display can be used as a high throughput selection platform to reprogram the "nonribosomal code" of A-domains. Copyright © 2013 Elsevier Ltd. All rights reserved.

Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: Synthesis, spectral characterization, antimicrobial and nuclease studies

NASA Astrophysics Data System (ADS)

Subbaraj, P.; Ramu, A.; Raman, N.; Dharmaraja, J.

2014-01-01

A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA = Schiff base and B = 2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, 1H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, 1H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique.

Use of 5-deazaFAD to study hydrogen transfer in the D-amino acid oxidase reaction.

PubMed

Hersh, L B; Jorns, M S

1975-11-25

The apoprotein of hog kidney D-amino acid oxidase was reconstituted with 5-deazaflavin adenine dinucleotide (5-deazaFAD) to yield a protein which contains 1.5 mol of 5-deazaFAD/mol of enzyme. The deazaFAD-containing enzyme forms complexes with benzoate, 2-amino benzoate, and 4-aminobenzoate which are both qualitatively and quantitatively similar to those observed with native enzyme. The complex with 2-aminobenzoate exhibits a new long wavelength absorption band characteristic of a flavin charge-transfer complex. The reconstituted enzyme exhibits no activity when assayed by D-alanine oxidation. However, the bound chromophore can be reduced by alanine, phenylalanine, proline, methionine, and valine, but not by glutamate or aspartate, indicating the deazaFAD enzyme retains the substrate specificity of the native enzyme. Reduction of the enzyme by D-alanine exhibits a 1.6-fold deuterium isotope effect. Reoxidation of the reduced enzyme occurred in the presence of pyruvate plus ammonia, but not with pyruvate alone or ammonia alone. beta-Phenylpyruvate and alpha-ketobutyrate, but not alpha-ketoglutarate could replace pyruvate. Reduced enzyme isolated following reaction with [alpha-3H]alanine was found to contain 0.5 mol of tritium/mol of deazaFADH2. After denaturation of the tritium-labeled enzyme, the radioactivity was identified as deazaFADH2. Reaction of the reduced tritium-labeled enzyme with pyruvate plus ammonia prior to denaturation yields [alpha-3H]alanine and unlabeled deazaFAD. These results suggest that reduction and reoxidation of enzyme-bound deazaFAD involves the stereo-specific transfer of alpha-hydrogen from substrate to deazaFAD.

A macrocyclic polyamine as an anion receptor in the capillary electrochromatographic separation of carbohydrates.

PubMed

Liu, Chuen-Ying; Chen, Tse-Hsien; Misra, Tarun Kumar

2007-06-22

An analytical approach of the 32-membered macrocyclic polyamine, 1,5,9,13,17,21,25,29-octaazacyclodotriacontane ([32]ane-N8) was described for the capillary electrochromatographic (CEC) separation of derivatized mono- and disaccharides. The column displayed reversal electroosmotic flow (EOF) at pH below 7.0, while a cathodic EOF was shown at pH above 7.0. The reductive amination of saccharides was carried out with p-aminobenzoic acid. Some parameters that affect the CEC separations were investigated. Several competitive ligands, such as Tris, EDTA and phosphate were also examined for the effect on the performance. We achieved a complete separation of all compounds as well as the excess derivatizing agent by using borate buffer (pH 9.0) in a mode of concentration gradient (60 mM inlet side and 70 mM outlet side). The relative standard deviation of the retention time measured for each sample was less than 4% in six continuous runs, suggesting that the bonded phase along with the gradient formed inside the column was quite stable. With the mixing modes of anion coordination, anion exchange, and shape discrimination, the interaction adequately accomplishes the separation of carbohydrates which are epimers or have different glycosidic linkage, although the electrophoretic migration is also involved in the separation mechanism.

Folate Biofortification in Hydroponically Cultivated Spinach by the Addition of Phenylalanine.

PubMed

Watanabe, Sho; Ohtani, Yuta; Tatsukami, Yohei; Aoki, Wataru; Amemiya, Takashi; Sukekiyo, Yasunori; Kubokawa, Seiichi; Ueda, Mitsuyoshi

2017-06-14

Folate is an important vitamin mainly ingested from vegetables, and folate deficiency causes various health problems. Recently, several studies demonstrated folate biofortification in plants or food crops by metabolic engineering through genetic modifications. However, the production and sales of genetically modified foods are under strict regulation. Here, we developed a new approach to achieve folate biofortification in spinach (Spinacia oleracea) without genetic modification. We hydroponically cultivated spinach with the addition of three candidate compounds expected to fortify folate. As a result of liquid chromatography tandem mass spectrometry analysis, we found that the addition of phenylalanine increased the folate content up to 2.0-fold (306 μg in 100 g of fresh spinach), representing 76.5% of the recommended daily allowance for adults. By measuring the intermediates of folate biosynthesis, we revealed that phenylalanine activated folate biosynthesis in spinach by increasing the levels of pteridine and p-aminobenzoic acid. Our approach is a promising and practical approach to cultivate nutrient-enriched vegetables.

Studies on the metabolism of benoxinate by human pseudocholinesterase.

PubMed

Dubbels, R; Schloot, W

1983-01-01

The local anesthetic drug benoxinate (oxybuprocaine, Novesine) is hydrolyzed to 3-butoxy-4-aminobenzoic acid. A rapid and simple spectrophotometric method for benoxinate hydrolysis by human plasma was developed. Benoxinate is hydrolyzed enzymatically by an esterase present in the serum. Heat stability characteristics and apparent affinity values of the benoxinate metabolizing enzyme were in the same range compared to benzoylcholine chloride hydrolysis. Apparent Vmax-values differ by a mean factor of about 18 between the hydrolysis of both substrates. Considerable interindividual variability of benoxinate hydrolysis and inhibition of the enzymatic reaction by dibucaine and sodium fluoride has been observed. Furthermore, enzyme activity with benoxinate as substrate is positively correlated (P less than 0.001) with benzoylcholine chloride hydrolysis. Therefore, we assume that benoxinate is metabolized by human pseudocholinesterase (PCHE, E.C. 3.1.1.8) and that ocular side effects after benoxinate application may be caused by altered metabolism of this drug, depending on genetically determined variants of pseudocholinesterase.

High resolution and high sensitivity methods for oligosaccharide mapping and characterization by normal phase high performance liquid chromatography following derivatization with highly fluorescent anthranilic acid.

PubMed

Anumula, K R; Dhume, S T

1998-07-01

Facile labeling of oligosaccharides (acidic and neutral) in a nonselective manner was achieved with highly fluorescent anthranilic acid (AA, 2-aminobenzoic acid) (more than twice the intensity of 2-aminobenzamide, AB) for specific detection at very high sensitivity. Quantitative labeling in acetate-borate buffered methanol (approximately pH 5.0) at 80 degreesC for 60 min resulted in negligible or no desialylation of the oligosaccharides. A high resolution high performance liquid chromatographic method was developed for quantitative oligosaccharide mapping on a polymeric-NH2bonded (Astec) column operating under normal phase and anion exchange (NP-HPAEC) conditions. For isolation of oligosaccharides from the map by simple evaporation, the chromatographic conditions developed use volatile acetic acid-triethylamine buffer (approximately pH 4.0) systems. The mapping and characterization technology was developed using well characterized standard glycoproteins. The fluorescent oligosaccharide maps were similar to the maps obtained by the high pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), except that the fluorescent maps contained more defined peaks. In the map, the oligosaccharides separated into groups based on charge, size, linkage, and overall structure in a manner similar to HPAEC-PAD with contribution of -COOH function from the label, anthranilic acid. However, selectivity of the column for sialic acid linkages was different. A second dimension normal phase HPLC (NP-HPLC) method was developed on an amide column (TSK Gel amide-80) for separation of the AA labeled neutral complex type and isomeric structures of high mannose type oligosaccharides. The oligosaccharides labeled with AA are compatible with biochemical and biophysical techniques, and use of matrix assisted laser desorption mass spectrometry for rapid determination of oligosaccharide mass map of glycoproteins is demonstrated. High resolution of NP-HPAEC and NP-HPLC methods combined with mass spectrometry (MALDI-TOF) can provide an effective technology for analyzing a wide repertoire of oligosaccharide structures and for determining the action of both transferases and glycosidases.

Rabbit N-acetyltransferase 2 genotyping method to investigate role of acetylation polymorphism on N- and O-acetylation of aromatic and heterocyclic amine carcinogens.

PubMed

Hein, David W; Doll, Mark A

2017-09-01

The rabbit was the initial animal model to investigate the acetylation polymorphism expressed in humans. Use of the rabbit model is compromised by lack of a rapid non-invasive method for determining acetylator phenotype. Slow acetylator phenotype in the rabbit results from deletion of the N-acetyltransferase 2 (NAT2) gene. A relatively quick and non-invasive method for identifying the gene deletion was developed and acetylator phenotypes confirmed by measurement of N- and O-acetyltransferase activities in hepatic cytosols. Rabbit liver cytosols catalyzed the N-acetylation of sulfamethazine (p = 0.0014), benzidine (p = 0.0257), 4-aminobiphenyl (p = 0.0012), and the O-acetylation of N-hydroxy-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP; p = 0.002) at rates significantly higher in rabbits possessing NAT2 gene than rabbits with NAT2 gene deleted. In contrast, hepatic cytosols catalyzed the N-acetylation of p-aminobenzoic acid (an N-acetyltransferase 1 selective substrate) at rates that did not differ significantly (p > 0.05) between rabbits positive and negative for NAT2. The new NAT2 genotyping method facilitates use of the rabbit model to investigate the role of acetylator polymorphism in the metabolism of aromatic and heterocyclic amine drugs and carcinogens.

Simultaneous determination of some ultraviolet-absorbing chemicals in sunscreen cosmetics using a high-performance liquid chromatography method.

PubMed

Liu, T; Wu, D

2011-10-01

A method of gradient elution high-performance liquid chromatography (HPLC) for simultaneous determination of 11 different ultraviolet-absorbing chemicals of phenylbenzlmldazole sulphonic acid, 4-aminobenzoic acid, benzophenone-4, benzophenone-3, isoamyl p-methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, ethylhexyl methoxycinnamate, homosalate, ethylhexyl salicylate, methylene bis-benzotriazolyl tetramethylbutyl phenol was developed for the application to sunscreen cosmetic products. In this study, an Agilent SB-C18 analytical column (250 × 4.6 mm, 5 μm) was utilized and methanol, tetrahydrofuran and perchloric acid aqueous solution (0.2 mL HClO(4) + 300 mL H(2)O) were used for gradient elution at a total flow rate of 1.0 mL min(-1). The optimum conditions for 11 different ultraviolet-absorbing chemicals analyses were investigated. All calibration curves showed good linear regression with UV detection (311 nm) within test ranges. The correlation coefficients were better than 0.999 in all cases. The assay was simple, selective, convenient and reproducible and is suitable for the determination of ultraviolet-absorbing chemicals in commercial sunscreen cosmetic products. The use frequency of 11 different ultraviolet absorbents in 100 sunscreen cosmetics was investigated and statistically analysed. The ultraviolet absorbent of maximum use frequency was ethylhexyl methoxycinnamate. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Selective neurotensin-derived internally quenched fluorogenic substrates for neurolysin (EC 3.4.24.16): comparison with thimet oligopeptidase (EC 3.4.24.15) and neprilysin (EC 3.4.24.11).

PubMed

Oliveira, V; Campos, M; Hemerly, J P; Ferro, E S; Camargo, A C; Juliano, M A; Juliano, L

2001-05-15

Internally quenched fluorescent peptides derived from neurotensin (pELYENKPRRPYIL) sequence were synthesized and assayed as substrates for neurolysin (EC 3.4.24.16), thimet oligopeptidase (EC 3.4.24.15 or TOP), and neprilysin (EC 3.4.24.11 or NEP). Abz-LYENKPRRPYILQ-EDDnp (where EDDnp is N-(2,4-dinitrophenyl)ethylenediamine and Abz is ortho-aminobenzoic acid) was derived from neurotensin by the introduction of Q-EDDnp at the C-terminal end of peptide and by the substitution of the pyroglutamic (pE) residue at N-terminus for Abz and a series of shorter peptides was obtained by deletion of amino acids residues from C-terminal, N-terminal, or both sides. Neurolysin and TOP hydrolyzed the substrates at P--Y or Y--I or R--R bonds depending on the sequence and size of the peptides, while NEP cleaved P-Y or Y-I bonds according to its S'(1) specificity. One of these substrates, Abz-NKPRRPQ-EDDnp was a specific and sensitive substrate for neurolysin (k(cat) = 7.0 s(-1), K(m) = 1.19 microM and k(cat)/K(m) = 5882 mM(-1). s(-1)), while it was completely resistant to NEP and poorly hydrolyzed by TOP and also by prolyl oligopeptidase (EC 3.4.21.26). Neurolysin concentrations as low as 1 pM were detected using this substrate under our conditions and its analogue Abz-NKPRAPQ-EDDnp was hydrolyzed by neurolysin with k(cat) = 14.03 s(-1), K(m) = 0.82 microM, and k(cat)/K(m) = 17,110 mM(-1). s(-1), being the best substrate so far described for this peptidase. Copyright 2001 Academic Press.

Cellobiose Dehydrogenase Aryl Diazonium Modified Single Walled Carbon Nanotubes: Enhanced Direct Electron Transfer through a Positively Charged Surface

PubMed Central

2011-01-01

One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500 μA cm−2 at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning. PMID:21417322

Cellobiose dehydrogenase aryl diazonium modified single walled carbon nanotubes: enhanced direct electron transfer through a positively charged surface.

PubMed

Tasca, Federico; Harreither, Wolfgang; Ludwig, Roland; Gooding, John Justin; Gorton, Lo

2011-04-15

One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500 μA cm(-2) at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning. © 2011 American Chemical Society

[Intermediary effectiveness of procaine and procaine metabolites following oral administration].

PubMed

Kaemmerer, K; Kietzmann, M

1989-01-01

The influence of orally administrated procaine hydrochloride and of its metabolites diethylaminoethanol, monoethylaminoethanol and ethanolamine on specific intermediary processes in rats was tested. While the animals got procaine hydrochloride in a single dose or via food the incorporation rate of amino acids in protein was measured in homogenisates of liver tissue by the incorporation of a mixture of 14C-amino acids. Procaine hydrochloride, the commercial product K. H. 3, as well as diethylaminoethanol, monoethylaminoethanol and ethanolamine increased the amino acid incorporation rate in a dose and time dependent mode, while p-aminobenzoic acid remained without any effect. The dose of procaine hydrochloride inducing a maximal reaction was in the range of 50 to 100 mg/kg b. w. (250 to 500 mg/kg food). The minimal active dose was nearly at 10 mg/kg b. w. Paying regard to a metabolic factor of 10 the effective dose-range is nearly the dose used in experience with human beings to influence geriatric complaints. In the study described here haematoporphyrine (a component of the commercial product K. H. 3, not absorbed) shows no specific intermediary effect. May be it promotes the intestinal absorption of procaine hydrochloride by protection against intestinal hydrolysis. The intermediary effect of procaine hydrochloride is to measure on cellular or subcellular level without compatibility to the activity as a local anaesthetic. With regard to other intermediary effects mentioned in the literature like growth promotion or inhibition of monoamine oxidase activity, it is discussed whether the increase of the hepatic amino acid incorporation rate is corresponding to geriatric experiences made with procaine hydrochloride.

Investigating tautomeric polymorphism in crystalline anthranilic acid using terahertz spectroscopy and solid-state density functional theory.

PubMed

Delaney, Sean P; Witko, Ewelina M; Smith, Tiffany M; Korter, Timothy M

2012-08-02

Terahertz spectroscopy is sensitive to the interactions between molecules in the solid-state and recently has emerged as a new analytical tool for investigating polymorphism. Here, this technique is applied for the first time to the phenomenon of tautomeric polymorphism where the crystal structures of anthranilic acid (2-aminobenzoic acid) have been investigated. Three polymorphs of anthranilic acid (denoted Forms I, II and III) were studied using terahertz spectroscopy and the vibrational modes and relative polymorph stabilities analyzed using solid-state density functional theory calculations augmented with London dispersion force corrections. Form I consists of both neutral and zwitterionic molecules and was found to be the most stable polymorph as compared to Forms II and III (both containing only neutral molecules). The simulations suggest that a balance between steric interactions and electrostatic forces is responsible for the favoring of the mixed neutral/zwitterion solid over the all neutral or all zwitterion crystalline arrangements.

Evolutionary differences in chromosomal locations of four early genes of the tryptophan pathway in fluorescent pseudomonads: DNA sequences and characterization of Pseudomonas putida trpE and trpGDC.

PubMed

Essar, D W; Eberly, L; Crawford, I P

1990-02-01

Pseudomonas putida possesses seven structural genes for enzymes of the tryptophan pathway. All but one, trpG, which encodes the small (beta) subunit of anthranilate synthase, have been mapped on the circular chromosome. This report describes the cloning and sequencing of P. putida trpE, trpG, trpD, and trpC. In P. putida and Pseudomonas aeruginosa, DNA sequence analysis as well as growth and enzyme assays of insertionally inactivated strains indicated that trpG is the first gene in a three-gene operon that also contains trpD and trpC. In P. putida, trpE is 2.2 kilobases upstream from the trpGDC cluster, whereas in P. aeruginosa, they are separated by at least 25 kilobases (T. Shinomiya, S. Shiga, and M. Kageyama, Mol. Gen. Genet., 189:382-389, 1983). The DNA sequence in P. putida shows an open reading frame on the opposite strand between trpE and trpGDC; this putative gene was not characterized. Evidence is also presented for sequence similarities in the 5' untranslated regions of trpE and trpGDC in both pseudomonads; the function of these regions is unknown, but it is possible that they play some role in regulation of these genes, since all the genes respond to repression by tryptophan. The sequences of the anthranilate synthase genes in the fluorescent pseudomonads resemble those of p-aminobenzoate synthase genes of the enteric bacteria more closely than the anthranilate synthase genes of those organisms; however, no requirement for p-aminobenzoate was found in the Pseudomonas mutants created in this study.

Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: synthesis, spectral characterization, antimicrobial and nuclease studies.

PubMed

Subbaraj, P; Ramu, A; Raman, N; Dharmaraja, J

2014-01-03

A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA=Schiff base and B=2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, (1)H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, (1)H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique. Copyright © 2013 Elsevier B.V. All rights reserved.

Hybrid molecule from O2-(2,4-dinitrophenyl)diazeniumdiolate and oleanolic acid: a glutathione S-transferase π-activated nitric oxide prodrug with selective anti-human hepatocellular carcinoma activity and improved stability.

PubMed

Fu, Junjie; Liu, Ling; Huang, Zhangjian; Lai, Yisheng; Ji, Hui; Peng, Sixun; Tian, Jide; Zhang, Yihua

2013-06-13

A series of hybrids from O(2)-(2,4-dinitrophenyl)diazeniumdiolate and oleanolic acid (OA) were designed, synthesized, and biologically evaluated as novel nitric oxide (NO)-releasing prodrugs that could be activated by glutathione S-transferase π (GSTπ) overexpressed in a number of cancer cells. It was discovered that the most active compound, 21, released high levels of NO selectively in HCC cells but not in the normal cells and exhibited potent antiproliferative activity in vitro as well as remarkable tumor-retarding effects in vivo. Compared with the reported GSTπ-activated prodrugs JS-K and PABA/NO, 21 exhibited remarkably improved stability in the absence of GSTπ. Importantly, the decomposition of 21 occurred in the presence of GSTπ and was much more effective than in glutathione S-transferase α. Additionally, 21 induced apoptosis in HepG2 cells by arresting the cell cycle at the G2/M phase, activating both the mitochondrion-mediated pathway and the MAPK pathway and enhancing the intracellular production of ROS.

Determination of the conformation of 2-hydroxy- and 2-aminobenzoic acid dimers using 13C NMR and density functional theory/natural bond order analysis: the central importance of the carboxylic acid carbon.

PubMed

Burnette, Ronald R; Weinhold, Frank

2006-07-20

The 13C chemical shift for the carboxylic acid carbon provides a powerful diagnostic probe to determine the preferred isomeric dimer structures of benzoic acid derivatives undergoing intra- and intermolecular H-bonding in the gas, solution and crystalline phases. We have employed hybrid density functional calculations and natural bond orbital analysis to elucidate the electronic origins of the observed 13C shieldings and their relationship to isomeric stability. We find that delocalizing interactions from the carbonyl oxygen lone pairs (nO) into vicinal carbon-oxygen and carbon-carbon antibonds (sigmaCO*,sigmaCC*) make critical contributions to the 13C shieldings, and these nO --> sigmaCO*, nO --> sigmaCC* interactions are in turn sensitive to the intramolecular interactions that dictate dimer structure and stability. The carboxyl carbon atom can thus serve as a useful detector of subtle structural and conformational features in this pharmacologically important class of carboxylic acid interactions.

Solid and liquid heat capacities of n-alkyl para-aminobenzoates near the melting point.

PubMed

Neau, S H; Flynn, G L

1990-11-01

The expression that relates the ideal mole fraction solubility of a crystalline compound to physicochemical properties of the compound includes a term involving the difference in the heat capacities of the solid and liquid forms of the solute, delta Cp. There are two alternate conventions which are employed to eliminate this term. The first assumes that the term involving delta Cp, or delta Cp itself, is zero. The alternate assumption assigns the value of the entropy of fusion to the differential heat capacity. The relative validity of these two assumptions was evaluated using the straight-chain alkyl para-aminobenzoates as test compounds. The heat capacities of the solid and liquid forms of each of the para-aminobenzoates, near the respective melting point, were determined by differential scanning calorimetry. The data lead one to conclude that the assumption that the differential heat capacity is not usually negligible and is better approximated by the entropy of fusion.

Microencapsulation of Clostridium difficile specific bacteriophages using microfluidic glass capillary devices for colon delivery using pH triggered release

PubMed Central

Vinner, Gurinder K.; Vladisavljević, Goran T.; Clokie, Martha R. J.

2017-01-01

The prevalence of pathogenic bacteria acquiring multidrug antibiotic resistance is a global health threat to mankind. This has motivated a renewed interest in developing alternatives to conventional antibiotics including bacteriophages (viruses) as therapeutic agents. The bacterium Clostridium difficile causes colon infection and is particularly difficult to treat with existing antibiotics; phage therapy may offer a viable alternative. The punitive environment within the gastrointestinal tract can inactivate orally delivered phages. C. difficile specific bacteriophage, myovirus CDKM9 was encapsulated in a pH responsive polymer (Eudragit® S100 with and without alginate) using a flow focussing glass microcapillary device. Highly monodispersed core-shell microparticles containing phages trapped within the particle core were produced by in situ polymer curing using 4-aminobenzoic acid dissolved in the oil phase. The size of the generated microparticles could be precisely controlled in the range 80 μm to 160 μm through design of the microfluidic device geometry and by varying flow rates of the dispersed and continuous phase. In contrast to free ‘naked’ phages, those encapsulated within the microparticles could withstand a 3 h exposure to simulated gastric fluid at pH 2 and then underwent a subsequent pH triggered burst release at pH 7. The significance of our research is in demonstrating that C. difficile specific phage can be formulated and encapsulated in highly uniform pH responsive microparticles using a microfluidic system. The microparticles were shown to afford significant protection to the encapsulated phage upon prolonged exposure to an acid solution mimicking the human stomach environment. Phage encapsulation and subsequent release kinetics revealed that the microparticles prepared using Eudragit® S100 formulations possess pH responsive characteristics with phage release triggered in an intestinal pH range suitable for therapeutic purposes. The results reported here provide proof-of-concept data supporting the suitability of our approach for colon targeted delivery of phages for therapeutic purposes. PMID:29023522

Copoly(imide-amides) containing hexafluoroisopropylidene

NASA Technical Reports Server (NTRS)

Irvin, David J.; Cassidy, Patrick E.; Cameron, Mitch L.

1990-01-01

The incorporation of the hexafluoroisopropylidene (HFIP or 6F) group into polymer backbones brings about important and useful changes in properties. These differences include increased thermal and environmental resistance and solubility and decreased dielectric constant and color. Several types of backbones have been substrates for the inclusion of HFIP and all results have reflected impressive property benefits. This project involved the incorporation of 6F groups into a poly(imide-amide) backbone by the condensation of a 6F-containing dianhydride with 4-aminobenzoic acid to yield a diimide terminated with two carboxylic acid groups. This diacid trimer was then polymerized with various diamines. The polymers were obtained in yields of 86-94 percent and with viscosities of 0.90-2.26 dL/g. They were stable to above 500 C and clear, colorless films could be cast from DMAc.

Inhibition of Long Chain Fatty Acyl-CoA Synthetase (ACSL) and Ischemia Reperfusion Injury

PubMed Central

Prior, Allan M.; Zhang, Man; Blakeman, Nina; Datta, Palika; Pham, Hung; Young, Lindon H.; Weis, Margaret T.; Hua, Duy H.

2014-01-01

Various triacsin C analogs, containing different alkenyl chains and carboxylic acid bioisoteres including 4-aminobenzoic acid, isothiazolidine dioxide, hydroxylamine, hydroxytriazene, and oxadiazolidine dione, were synthesized and their inhibitions of long chain fatty acyl-CoA synthetase (ACSL) were examined. Two methods, a cell-based assay of ACSL activity and an in situ [14C]-palmitate incorporation into extractable lipids were used to study the inhibition. Using an in vivo leukocyte recruitment inhibition protocol, the translocation of one or more cell adhesion molecules from the cytoplasm to the plasma membrane on either the endothelium or leukocyte or both was inhibited by inhibitors 1, 9, and triacsin C. The results suggest that inhibition of ACSL may attenuate the vascular inflammatory component associated with ischemia reperfusion injury and lead to a decrease of infarct expansion. PMID:24480468

Effect of some ultraviolet light absorbers on photo-stabilization of azadirachtin-A.

PubMed

Deota, P T; Upadhyay, P R; Patel, K B; Mehta, K J; Varshney, A K; Mehta, M H

2002-10-01

The effect of photo-stabilization of Azadirachtin-A (Aza-A) was examined when exposed to sunlight and ultraviolet light in the presence of four structurally different ultraviolet stabilizers namely 4-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered at different time intervals from slides exposed to different light conditions with and without UV stabilizers as well as kinetic studies indicated that the addition of phenyl salicylate in methanolic solution of Aza-A (in 1:1 mole ratio) provides the best photo-stabilization of Aza-A molecule among the four UV stabilizers studied.

Determination of 3-O- and 4-O-methylated monosaccharide constituents in snail glycans.

PubMed

Stepan, Herwig; Bleckmann, Christina; Geyer, Hildegard; Geyer, Rudolf; Staudacher, Erika

2010-07-02

The N- and O-glycans of Arianta arbustorum, Achatina fulica, Arion lusitanicus and Planorbarius corneus were analysed for their monosaccharide pattern by reversed-phase HPLC after labelling with 2-aminobenzoic acid or 3-methyl-1-phenyl-2-pyrazolin-5-one and by gas chromatography-mass spectrometry. Glucosamine, galactosamine, mannose, galactose, glucose, fucose and xylose were identified. Furthermore, three different methylated sugars were detected: 3-O-methyl-mannose and 3-O-methyl-galactose were confirmed to be a common snail feature; 4-O-methyl-galactose was detected for the first time in snails. Copyright 2010 Elsevier Ltd. All rights reserved.

Specificity studies on Kallikrein-related peptidase 7 (KLK7) and effects of osmolytes and glycosaminoglycans on its peptidase activity.

PubMed

Oliveira, Juliana R; Bertolin, Thiago C; Andrade, Douglas; Oliveira, Lilian C G; Kondo, Marcia Y; Santos, Jorge A N; Blaber, Michael; Juliano, Luiz; Severino, Beatrice; Caliendo, Giuseppe; Santagada, Vincenzo; Juliano, Maria A

2015-01-01

KLK7 substrate specificity was evaluated by families of fluorescence resonance energy transfer (FRET) peptides derived from Abz-KLFSSK-Q-EDDnp (Abz=ortho-aminobenzoic acid and Q-EDDnp=glutaminyl-N-[2,4-dinitrophenyl] ethylenediamine), by one bead-one peptide FRET peptide library in PEGA resin, and by the FRET peptide libraries Abz-GXX-Z-XX-Q-EDDnp (Z and X are fixed and random natural amino acids, respectively). KLK7 hydrolyzed preferentially F, Y or M, and its S1' and S2' subsites showed selectivity for hydrophilic amino acids, particularly R and K. This set of specificities was confirmed by the efficient kininogenase activity of KLK7 on Abz-MISLM(↓)KRPPGFSPF(↓)RSSRI-NH2 ((↓)indicates cleavage), hydrolysis of somatostatin and substance P and inhibition by kallistatin. The peptide Abz-NLY(↓)RVE-Q-EDDnp is the best synthetic substrate so far described for KLK7 [kcat/Km=455 (mMs)(-1)] that was designed from the KLK7 substrate specificity analysis. It is noteworthy that the NLYRVE sequence is present in human semaphorin 6B. KLK7 is activated by GAGs, inhibited by neutral salts, and activated by high concentration of kosmotropic salt. Pyroglutamic acid inhibited KLK7 (Ki=33mM) and is present in skin moisturizing factor (124mM). The KLK7 specificity described here and elsewhere reflects its participation in patho-physiological events in skin, the gastrointestinal tract and central nervous system, where KLK7 is significantly expressed. Copyright © 2014. Published by Elsevier B.V.

Inhibition of PCAF histone acetyltransferase, cytotoxicity and cell permeability of 2-acylamino-1-(3- or 4-carboxy-phenyl)benzamides.

PubMed

Park, Woong Jae; Ma, Eunsook

2012-11-05

Small molecule HAT inhibitors are useful tools to unravel the role of histone acetyltransferases (HATs) in the cell and they also have relevance in oncology. We synthesized a series of 2-acylamino-1-(3- or 4-carboxyphenyl)benzamides 8–19 bearing C6, C8, C10, C12, C14, and C16 acyl chains at the 2-amino position of 2-aminobenzoic acid. Enzyme inhibition of these compounds was investigated using in vitro PCAF HAT assays. The inhibitory activities of compounds 8–10, 16, and 19 were similar to that of anacardic acid, and 17 was found to be more active than anacardic acid at 100 μM. Compounds 11–15 showed the low inhibitory activity on PCAF HAT. The cytotoxicity of the synthesized compounds was evaluated by SRB (sulforhodamine B) assay against seven human cancer cell lines: HT-29 (colon), HCT-116 (colon), MDA-231 (breast), A549 (lung), Hep3B (hepatoma), HeLa (cervical) and Caki (kidney) and one normal cell line (HSF). Compound 17 was more active than anacardic acid against human colon cancer (HCT 116, IC(50): 29.17 μM), human lung cancer (A549, IC₅₀: 32.09 μM) cell lines. 18 was more active than anacardic acid against human colon cancer (HT-29, IC₅₀: 35.49 μM and HCT 116, IC₅₀: 27.56 μM), human lung cancer (A549, IC₅₀: 30.69 μM), and human cervical cancer (HeLa, IC₅₀: 34.41 μM) cell lines. The apparent permeability coefficient (P(app), cm/s) values of two compounds (16 and 17) were evaluated as 68.21 and 71.48 × 10⁻⁶ cm/s by Caco-2 cell permeability assay.

Synthesis, characterization and biocidal activity of new organotin complexes of 2-(3-oxocyclohex-1-enyl)benzoic acid.

PubMed

Vieira, Flaviana T; de Lima, Geraldo M; Maia, José R da S; Speziali, Nivaldo L; Ardisson, José D; Rodrigues, Leonardo; Correa, Ary; Romero, Oscar B

2010-03-01

The reaction of 1,3-cyclohexadione with 2-aminobenzoic acid has produced the 2-(3-oxocyclohex-1-enyl)benzoic acid (HOBz). Subsequent reactions of the ligand with organotin chlorides led to [Me(2)Sn(OBz)O](2) (1), [Bu(2)Sn(OBz)O](2) (2), [Ph(2)Sn(OBz)O](2) (3), [Me(3)Sn(OBz)] (4), [Bu(3)Sn(OBz)] (5) and [Ph(3)Sn(OBz)] (6). All complexes have been fully characterized. In addition the structure of complexes (2) and (4) have been authenticated by X-ray crystallography. The biological activity of all derivatives has been screened against Cryptococcus neoformans and Candida albicans. In addition we have performed toxicological testes employing human kidney cell. The complexes (3), (5) and (6) displayed the best values of inhibition of the fungus growing, superior to ketoconazole. Compound (5) presented promising results in view of the antifungal and cytotoxicity assays. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

Quantification of Structural Isomers via Mode-Selective Irmpd

NASA Astrophysics Data System (ADS)

Polfer, Nicolas C.

2016-06-01

Mixtures of structural isomers can pose a challenge for vibrational ion spectroscopy. In cases where particular structures display diagnostic vibrations, these structures can be selectively "burned away". In ion traps, the ion population can be subjected to multiple laser shots, in order to fully deplete a particular structure, in effect allowing a quantification of this structure. Protonated para-amino benzoic acid (PABA) serves as an illustrative example. PABA is known to preferentially exist in the N-protonated (N-prot) form in solution, but in the gas phase it is energetically favorable in the O-protonated (O-prot) form. As shown in Figure 1, the N-prot structure can be kinetically trapped in the gas phase when sprayed from non-protic solvent, whereas the O-prot structure is obtained when sprayed from protic solvents, analogous to results by others [1,2]. y parking the light source on the diagnostic 3440 wn mode, the percentage of the O-prot structure can be determined, and by default the remainder is assumed to adopt the N-prot structure. It will be shown that the relative percentages of O-prot vs N-prot are highly dependent on the solvent mixture, going from close to 0% O-prot in non-protic solvents, to 99% in protic solvents. Surprisingly, water behaves much more like a non-protic solvent than methanol. It is observed that the capillary temperature, which aids droplet desolvation by black-body radiation in the ESI source, is critical to promote the appearance of O-prot structures. These results are consistent with the picture that a protic bridge mechanism is at play to facilitate proton transfer, and thus allow conversion from N-prot to O-prot, but that this mechanism is subject to appreciable kinetic barriers on the timescale of solvent evaporation. 1. J. Phys. Chem. A 2011, 115, 7625. 2. Anal. Chem. 2012, 84, 7857.

A new method for the quantification of monosaccharides, uronic acids and oligosaccharides in partially hydrolyzed xylans by HPAEC-UV/VIS.

PubMed

Lorenz, Dominic; Erasmy, Nicole; Akil, Youssef; Saake, Bodo

2016-04-20

A new method for the chemical characterization of xylans is presented, to overcome the difficulties in quantification of 4-O-methyl-α-D-glucuronic acid (meGlcA). In this regard, the hydrolysis behavior of xylans from beech and birch wood was investigated to obtain the optimum conditions for hydrolysis, using sulfuric acid. Due to varying linkage strengths and degradation, no general method for complete hydrolysis can be designed. Therefore, partial hydrolysis was applied, yielding monosaccharides and small meGlcA containing oligosaccharides. For a new method by HPAEC-UV/VIS, these samples were reductively aminated by 2-aminobenzoic acid. By quantification of monosaccharides and oligosaccharides, as well as comparison with borate-HPAEC and (13)C NMR-spectroscopy, we revealed that the concentrations meGlcA are significantly underestimated compared to conventional methods. The detected concentrations are 85.4% (beech) and 76.3% (birch) higher with the new procedure. Furthermore, the quantified concentrations of xylose were 9.3% (beech) and 6.5% (birch) higher by considering the unhydrolyzed oligosaccharides as well. Copyright © 2015 Elsevier Ltd. All rights reserved.

Elucidation of sulfadoxine resistance with structural models of the bifunctional Plasmodium falciparum dihydropterin pyrophosphokinase-dihydropteroate synthase.

PubMed

de Beer, Tjaart A P; Louw, Abraham I; Joubert, Fourie

2006-07-01

Resistance of the most virulent human malaria parasite, Plasmodium falciparum, to antifolates is spreading with increasing speed, especially in Africa. Antifolate resistance is mainly caused by point mutations in the P. falciparum dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) target proteins. Homology models of the bifunctional P. falciparum dihydropterin pyrophosphokinase-dihydropteroate synthase (PPPK-DHPS) enzyme as well as the separate domains complete with bound substrates were constructed using the crystal structures of Saccharomyces cerevisiae (PPPK-DHPS), Mycobacterium tuberculosis (DHPS), Bacillus anthracis (DHPS), and Escherichia coli (PPPK) as templates. The resulting structures were subsequently solvated and refined using molecular dynamics. The active site residues of DHPS are highly conserved in S. cerevisiae, M. tuberculosis, E. coli, S. aureus, and B. anthracis, an attribute also shared by P. falciparum DHPS. Sulfadoxine was superimposed into the equivalent position of the p-aminobenzoic acid substrate and its binding parameters were refined using minimization and molecular dynamics. Sulfadoxine appears to interact mainly with P. falciparum DHPS mainly through hydrophobic interactions. Rational explanations are provided by the model for the sulfadoxine resistance-causing effects of four of the five known mutations in P. falciparum DHPS. A possible structure for the bifunctional PPPK-DHPS was derived from the structure from the S. cerevisiae bifunctional enzyme. The active site residues of P. falciparum PPPK are also conserved when compared to S. cerevisiae, Haemophilus influenzae, and E. coli. The informative nature of these models opens up avenues for structure-based drug design approaches toward the development of alternative and more effective inhibitors of P. falciparum PPPK-DHPS.

The role of lysine(100) in the binding of acetylcoenzyme A to human arylamine N-acetyltransferase 1: implications for other acetyltransferases.

PubMed

Minchin, Rodney F; Butcher, Neville J

2015-04-01

The arylamine N-acetyltransferases (NATs) catalyze the acetylation of aromatic and heterocyclic amines as well as hydrazines. All proteins in this family of enzymes utilize acetyl coenzyme A (AcCoA) as an acetyl donor, which initially binds to the enzyme and transfers an acetyl group to an active site cysteine. Here, we have investigated the role of a highly conserved amino acid (Lys(100)) in the enzymatic activity of human NAT1. Mutation of Lys(100) to either a glutamine or a leucine significantly increased the Ka for AcCoA without changing the Kb for the acetyl acceptor p-aminobenzoic acid. In addition, substrate inhibition was more marked with the mutant enzymes. Steady state kinetic analyzes suggested that mutation of Lys(100) to either leucine or glutamine resulted in a less stable enzyme-cofactor complex, which was not seen with a positively charged arginine at this position. When p-nitrophenylacetate was used as acetyl donor, no differences were seen between the wild-type and mutant enzymes because p-nitrophenylacetate is too small to interact with Lys(100) when bound to the active site. Using 3'-dephospho-AcCoA as the acetyl donor, kinetic data confirmed that Ly(100) interacts with the 3'-phosphoanion to stabilize the enzyme-cofactor complex. Mutation of Lys(100) decreases the affinity of AcCoA for the protein and increases the rate of CoA release. Crystal structures of several other unrelated acetyltransferases show a lysine or arginine residue within 3Å of the 3'-phosphoanion of AcCoA, suggesting that this mechanism for stabilizing the complex by the formation of a salt bridge may be widely applicable in nature. Copyright © 2015 Elsevier Inc. All rights reserved.

Electron Detachment Dissociation (EDD) of Fluorescently Labeled Sialylated Oligosaccharides

PubMed Central

Zhou, Wen; Håkansson, Kristina

2012-01-01

We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared to IRMPD. Neutral losses and satellite ions such as C – 2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared to 2-AA labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. PMID:22120881

Synthesis, structure, and magnetic properties of two 1-D helical coordination polymeric Cu(II) complexes

NASA Astrophysics Data System (ADS)

Bian, He-Dong; Yang, Xiao-E.; Yu, Qing; Chen, Zi-Lu; Liang, Hong; Yan, Shi-Ping; Liao, Dai-Zheng

2008-01-01

Two helical coordination polymeric copper(II) complexes bearing amino acid Schiff bases HL or HL', which are condensed from 2-hydroxy-1-naphthaldehyde with 2-aminobenzoic acid or L-valine, respectively, have been prepared and characterised by X-ray crystallography. In [CuL] n ( 1) the copper(II) atoms are bridged by syn- anti carboxylate groups giving infinite 1-D right-handed helical chains which are further connected by weak C-H⋯Cu interactions to build a 2-D network. While in [CuL'] n ( 2) the carboxylate group acts as a rare monatomic bridge to connect the adjacent copper(II) atoms leading to the formation of a left-handed helical chain. Magnetic susceptibility measurements indicate that 1 exhibits weak ferromagnetic interactions whereas an antiferromagnetic coupling is established for 2. The magnetic behavior can be satisfactorily explained on the basis of the structural data.

A multi-responsive luminescent sensor based on a super-stable sandwich-type terbium(iii)-organic framework.

PubMed

Wen, Guo-Xuan; Han, Min-Le; Wu, Xue-Qian; Wu, Ya-Pan; Dong, Wen-Wen; Zhao, Jun; Li, Dong-Sheng; Ma, Lu-Fang

2016-10-04

A super-stable multifunctional terbium(iii)-organic framework, namely {[Tb(TATAB) (H 2 O) 2 ]·NMP·H 2 O} n (Tb-MOF, H 3 TATAB = 4,4',4''-s-triazine-1,3,5-triyltri-m-aminobenzoic acid, NMP = N-methyl-2-pyrrolidone) was synthesized. Tb-MOF exhibits a 2D sql structure with binuclear [Tb 2 (COO) 4 (H 2 O) 4 ] 2+ units as 4-connected nodes, and free water and NMP molecules are inserted between 2D layers through hydrogen-bonding interactions, forming a sandwich-type architecture. Observably, such a framework remains intact in a remarkable variety of environments such as common solvents and aqueous solutions with metal cations and inorganic anions, as well as with a pH ranging from 1 to 13. In particular, Tb-MOF can not only detect small organic molecules, metal cations and inorganic anions with high sensitivity and high selectivity, but also can accurately detect explosive 2-nitrophenol, 3-nitrophenol, 4-nitrophenol and 2,4,6-trinitrophenol in water. Its luminescence quenching response to Fe 3+ and Cr 2 O 7 2- ions can be explained in terms of the competitive absorption mechanism. In addition, the luminescence intensity of Tb-MOF is strongly correlated with the pH value in a pH range from 1 to 13. Thus, this material can be potentially used as a multi-responsive luminescent sensor.

Photocontact allergy to oxybenzone: ten years of experience.

PubMed

Szczurko, C; Dompmartin, A; Michel, M; Moreau, A; Leroy, D

1994-08-01

Intolerance of sunscreen agents has often been reported in the literature. This mainly comprises photosensitization to sunscreens such as oxybenzone. The aims of this study were to establish the incidence of photocontact allergy to oxybenzone and its relationship with the use of other cosmetics. From 1982 to 1992 we performed photopatch tests on 283 patients with suspected photodermatosis. Forty-six patients (16%) had positive reactions: 61 positive photopatch tests and 9 positive patch tests. Photocontact allergy to sunscreens was divided into 2 main groups: 35 cases to oxybenzone and 17 cases to para-aminobenzoic acid and its derivatives. Among our 35 cases of photoallergy to oxybenzone, more than one third had photoallergy to a daily moisturizer that contained oxybenzone.

Microwave-assisted synthesis of 3-aminobenzo[b]thiophene scaffolds for the preparation of kinase inhibitors.

PubMed

Bagley, Mark C; Dwyer, Jessica E; Molina, Maria D Beltran; Rand, Alexander W; Rand, Hayley L; Tomkinson, Nicholas C O

2015-06-28

Microwave irradiation of 2-halobenzonitriles and methyl thioglycolate in the presence of triethylamine in DMSO at 130 °C provides rapid access to 3-aminobenzo[b]thiophenes in 58-96% yield. This transformation has been applied in the synthesis of the thieno[2,3-b]pyridine core motif of LIMK1 inhibitors, the benzo[4,5]thieno[3,2-e][1,4]diazepin-5(2H)-one scaffold of MK2 inhibitors and a benzo[4,5]thieno[3,2-d]pyrimidin-4-one inhibitor of the PIM kinases.

In vitro and in vivo estrogenicity of UV screens.

PubMed Central

Schlumpf, M; Cotton, B; Conscience, M; Haller, V; Steinmann, B; Lichtensteiger, W

2001-01-01

Ultraviolet (UV) screens are increasingly used as a result of growing concern about UV radiation and skin cancer; they are also added to cosmetics and other products for light stability. Recent data on bioaccumulation in wildlife and humans point to a need for in-depth analyses of systemic toxicology, in particular with respect to reproduction and ontogeny. We examined six frequently used UVA and UVB screens for estrogenicity in vitro and in vivo. In MCF-7 breast cancer cells, five out of six chemicals, that is, benzophenone-3 (Bp-3), homosalate (HMS), 4-methyl-benzylidene camphor (4-MBC), octyl-methoxycinnamate (OMC), and octyl-dimethyl-PABA (OD-PABA), increased cell proliferation with median effective concentrations (EC(50)) values between 1.56 and 3.73 microM, whereas butyl-methoxydibenzoylmethane (B-MDM) was inactive. Further evidence for estrogenic activity was the induction of pS2 protein in MCF-7 cells and the blockade of the proliferative effect of 4-MBC by the estrogen antagonist ICI 182,780. In the uterotrophic assay using immature Long-Evans rats that received the chemicals for 4 days in powdered feed, uterine weight was dose-dependently increased by 4-MBC (ED(50 )309mg/kg/day), OMC (ED(50) 935 mg/kg/day), and weakly by Bp-3 (active at 1,525 mg/kg/day). Three compounds were inactive by the oral route in the doses tested. Dermal application of 4-MBC to immature hairless (hr/hr) rats also increased uterine weight at concentrations of 5 and 7.5% in olive oil. Our findings indicate that UV screens should be tested for endocrine activity, in view of possible long-term effects in humans and wildlife. PMID:11333184

The cholesteryl octanoate breath test: a new procedure for detection of pancreatic insufficiency in the rat.

PubMed

Mundlos, S; Rhodes, J B; Hofmann, A F

1987-09-01

A breath test for the detection of pancreatic insufficiency was developed and tested in rats. The test features the hydrophobic molecule cholesteryl-1-14C-octanoate, which liberates 14C-octanoic acid when hydrolyzed by carboxyl ester lipase (cholesterol esterase). The 14C-octanoate is absorbed passively and rapidly metabolized to 14CO2, which is excreted in expired air. The compound was administered as an emulsion of cholesteryl octanoate, triglyceride, and lecithin to rats with mild pancreatic insufficiency induced by injecting the pancreatic duct with zein. The animals had exocrine pancreatic hypofunction based on the enzyme content of pancreas at autopsy. Amylase was reduced by 97.1 +/- 1.4%, whereas chymotrypsin was reduced by 73 +/- 14%. The p-aminobenzoic acid test was abnormal at 1 wk (21.68 +/- 8.4%), but become normal at 3 months (72.08 +/- 5.8%) after zein injection. Despite this, the animals gained weight and absorbed fat normally. The 14CO2 excretion rate in the 110-min interval after feeding was significantly reduced to 60% of sham-operated animals. Peak 14CO2 collections 20 min after feeding were reduced by 75 +/- 11%. 14CO2 output was completely normalized by administration of pancreatin prior to the test meal. The results suggest that a sensitive, noninvasive method for detecting deficiency of pancreatic carboxyl ester lipase (cholesterol esterase) secretion in the rat has been developed.

Virucidal agents in the eve of manorapid synergy®

PubMed Central

Galabov, Angel S.

2007-01-01

Virucidal agents are chemical substances that attack and inactivate viral particles outside the cell (virions). In general this is accomplished by damaging their protein shells (capsid) or the substance penetrates the core itself, where it destroys the genetic material. Damage to the virion structure is also possible. These agents are used not only for traditional surface disinfection or sterilization of blood, blood products, and other medicinal products as well as in antiviral chemotherapy. They have also been used in recent times for inactivation of viruses in foodstuffs, detergents or cosmetics. Below is given an overview of the data currently available on the performance of these substances when used for the latter applications (cleaning and cosmetics). These include: hydrogen peroxide, hypochlorites, cupric and ferric ions, per-acids ethanol, parachlorometaxylenol in a sodium C14-16 olefin sulfonate, glutaraldehyde, quaternary ammonium salts, chlorhexidine and chlorhexidine gluconate, curdline sulphate, glycerol, lipids, azodicarbonamide, cicloxolone sodium, dichlorisocyanuric acid (sodium salt), benzalkonium salts, disulfate benzamides and benzisothiazolones, congo red, ascorbic acid, nonoxynol-9, para-aminobenzoic acid, bis(monosuccinamide) derivative of p,p’-bis(2-aminoethyl) diphenlyi-C60) (fullerene). merocyanine, benzoporphyrin derivative monoacid ring A, rose bengal, hypericin, hypocrellin A, anthraquinones extracted from plants, sulfonated anthraquinones and other anthraquinone derivatives gramicidine, gossypol, garlic (Allium sativum) extract and its components: ajoene, diallyl thiosulfinate (allicin), allyl methyl thioulfinate, methyl allyl thiosulfinate, extracts of ledium, motherworth, celandine, black currant, coaberry and bilberry, extract of Cordia salicifolia, steam distillate from Houttuynia cordata (Saururaceae) and its component, 5,6,7-trimethoxyflavone from Calicarpa japonica, isoscullarein (5,7,8,4’-tetrahydroxyflavone) from Scutellaria baikalensis and isoscutellarein-8-methylether, alkaloids and phytosteryl ester compounds. PMID:20200679

Capillary electrophoresis determination of glucosamine in nutraceutical formulations after labeling with anthranilic acid and UV detection.

PubMed

Volpi, Nicola

2009-04-05

A new robust CE method for the determination of the glucosamine (GlcN) content in nutraceutical formulations is described after its derivatization with anthranilic acid (2-aminobenzoic acid, AA). The CE separation of derivatized GlcN with AA was performed on an uncoated fused-silica capillary tube (50 microm I.D.) using an operating pH 7.0 buffer of 150 mM boric acid/50 mM NaH2PO4 and UV detection at 214 nm. The method was validated for specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). The detector response for GlcN was linear over the selected concentration range from 240 to 2400 pg (40-400 microg/mL) with a correlation coefficient greater than 0.980. The intra- and inter-day variations (CV%) were between 0.5 and 0.9 for migration time, and between 2.8 and 4.3 for peak area, respectively. The LOD and the LOQ of the method were approximately 200 and 500 pg, respectively. The intra- and inter-day accuracy was estimated to range from 2.8% to 5.1%, while the percent recoveries of GlcN in formulations were calculated to be about 100% after simple centrifugation for 10 min, lyophilization and derivatization with AA. The CE method was applied to the determination of GlcN content, in the form of GlcN-hydrochloride or GlcN-sulfate, of several nutraceutical preparations in the presence of other ingredients, i.e. chondroitin sulfate, vitamin C and/or methylsulfonylmethane (MSM) as well as salts and other agents. The quantitative results obtained were in total conformity with the label claims.

Metabolic Engineering of the Shikimate Pathway for Production of Aromatics and Derived Compounds—Present and Future Strain Construction Strategies

PubMed Central

Averesch, Nils J. H.; Krömer, Jens O.

2018-01-01

The aromatic nature of shikimate pathway intermediates gives rise to a wealth of potential bio-replacements for commonly fossil fuel-derived aromatics, as well as naturally produced secondary metabolites. Through metabolic engineering, the abundance of certain intermediates may be increased, while draining flux from other branches off the pathway. Often targets for genetic engineering lie beyond the shikimate pathway, altering flux deep in central metabolism. This has been extensively used to develop microbial production systems for a variety of compounds valuable in chemical industry, including aromatic and non-aromatic acids like muconic acid, para-hydroxybenzoic acid, and para-coumaric acid, as well as aminobenzoic acids and aromatic α-amino acids. Further, many natural products and secondary metabolites that are valuable in food- and pharma-industry are formed outgoing from shikimate pathway intermediates. (Re)construction of such routes has been shown by de novo production of resveratrol, reticuline, opioids, and vanillin. In this review, strain construction strategies are compared across organisms and put into perspective with requirements by industry for commercial viability. Focus is put on enhancing flux to and through shikimate pathway, and engineering strategies are assessed in order to provide a guideline for future optimizations. PMID:29632862

Codominant Expression of N-Acetylation and O-Acetylation Activities Catalyzed by N-Acetyltransferase 2 in Human Hepatocytes

PubMed Central

Doll, Mark A.; Zang, Yu; Moeller, Timothy

2010-01-01

Human populations exhibit genetic polymorphism in N-acetylation capacity, catalyzed by N-acetyltransferase 2 (NAT2). We investigated the relationship between NAT2 acetylator genotype and phenotype in cryopreserved human hepatocytes. NAT2 genotypes determined in 256 human samples were assigned as rapid (two rapid alleles), intermediate (one rapid and one slow allele), or slow (two slow alleles) acetylator phenotypes based on functional characterization of the NAT2 alleles reported previously in recombinant expression systems. A robust and significant relationship was observed between deduced NAT2 phenotype (rapid, intermediate, or slow) and N-acetyltransferase activity toward sulfamethazine (p < 0.0001) and 4-aminobiphenyl (p < 0.0001) and for O-acetyltransferase-catalyzed metabolic activation of N-hydroxy-4-aminobiphenyl (p < 0.0001), N-hydroxy-2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (p < 0.01), and N-hydroxy-2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (p < 0.0001). NAT2-specific protein levels also significantly associated with the rapid, intermediate, and slow NAT2 acetylator phenotypes (p < 0.0001). As a negative control, p-aminobenzoic acid (an N-acetyltransferase 1-selective substrate) N-acetyltransferase activities from the same samples did not correlate with the three NAT2 acetylator phenotypes (p > 0.05). These results clearly document codominant expression of human NAT2 alleles resulting in rapid, intermediate, and slow acetylator phenotypes. The three phenotypes reflect levels of NAT2 protein catalyzing both N- and O-acetylation. Our results suggest a significant role of NAT2 acetylation polymorphism in arylamine-induced cancers and are consistent with differential cancer risk and/or drug efficacy/toxicity in intermediate compared with rapid or slow NAT2 acetylator phenotypes. PMID:20430842

Inhibitory effects of cytostatically active 6-aminobenzo[c]phenanthridines on cytochrome P450 enzymes in human hepatic microsomes.

PubMed

Zebothsen, Inga; Kunze, Thomas; Clement, Bernd

2006-07-01

Besides assays for the evaluation of efficacy new drug candidates have to undergo extensive testings for enhancement of pharmaceutical drug safety and optimization of application. The objective of the present work was to investigate the pharmacokinetic drug drug interaction potential for the cytostatically active 6-aminobenzo[c]phenanthridines BP-11 (6-amino-11,12-dihydro-11-(4-hydroxy-3,5-dimethoxyphenyl)benzo[c]phenanthridine) and BP-D7 (6-amino-11-(3,4,5-trimethoxyphenyl)benzo[c]phenanthridine) in vitro through incubation with human hepatic microsomes and marker substrates. For these studies the cytochrome P-450 isoenzymes and corresponding marker substrates recommended by the EMEA (The European Agency for the Evaluation of Medicinal Products) were chosen. In detail these selective substrates were caffeine (CYP1A2), coumarin (CYP2A6), tolbutamide (CYP2C9), S-(+)-mephenytoin (CYP2C19), dextromethorphane (CYP2D6), chlorzoxazone (CYP2E1) and testosterone (CYP3A4). Incubations with each substrate were carried out without a possible inhibitor and in the presence of a benzo[c]phenanthridine or a selective inhibitor at varying concentrations. Marker activities were determined by HPLC (high performance liquid chromatography). For the isoenzymes showing more than 50% inhibition by the addition of 20 microM BP-11 or BP-D7 additional concentrations of substrate and inhibitor were tested for a characterization of the inhibition. The studies showed a moderate risk for BP-11 for interactions with the cytochrome P-450 isoenzymes CYP1A2, CYP2C9, CYP2D6 and CYP3A4. BP-D7, the compound with the highest cytotstatic efficacy, showed only a moderate risk for interactions with drugs, also metabolized by CYP3A4.

Structures of asparagine-linked oligosaccharides from hen egg-yolk antibody (IgY). Occurrence of unusual glucosylated oligo-mannose type oligosaccharides in a mature glycoprotein.

PubMed

Ohta, M; Hamako, J; Yamamoto, S; Hatta, H; Kim, M; Yamamoto, T; Oka, S; Mizuochi, T; Matsuura, F

1991-10-01

Asparagine-linked oligosaccharides present on hen egg-yolk immunoglobulin, termed IgY, were liberated from the protein by hydrazinolysis. After N-acetylation, the oligosaccharides were labelled with a UV-absorbing compound, p-aminobenzoic acid ethyl ester (ABEE). The ABEE-derivatized oligosaccharides were fractionated by anion exchange, normal phase and reversed phase HPLC, and their structures were determined by a combination of sugar composition analysis, methylation analysis, negative ion FAB-MS, 500 MHz 1H-NMR and sequential exoglycosidase digestions. IgY contained monoglucosylated oligomannose type oligosaccharides with structures of Glc alpha 1-3Man7-9-GlcNAc-GlcNAc, oligomannose type oligosaccharides with the size range of Man5-9GlcNAc-GlcNAc, and biantennary complex type oligosaccharides with core region structure of Man alpha 1-6(+/- GlcNAc beta 1-4)(Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4(+/- Fuc alpha 1-6)GlcNAc. The glucosylated oligosaccharides, Glc1Man8GlcNAc2 and Glc1Man7GlcNAc2, have not previously been reported in mature glycoproteins from any source.

Evidence for significantly enhancing reduction of Azo dyes in Escherichia coli by expressed cytoplasmic Azoreductase (AzoA) of Enterococcus faecalis.

PubMed

Feng, J; Heinze, T M; Xu, H; Cerniglia, C E; Chen, H

2010-05-01

Although cytoplasmic azoreductases have been purified and characterized from various bacteria, little evidence demonstrating that these azoreductases are directly involved in azo dye reduction in vivo is known. In order to evaluate the contribution of the enzyme to azo dye reduction in vivo, experiments were conducted to determine the effect of a recombinant cytoplasmic azoreductase (AzoA) from Enterococcus faecalis expressed in Escherichia coli on the rate of metabolism of Methyl Red, Ponceau BS and Orange II. The intact cells that contained IPTG induced AzoA had a higher rate of dye reduction with increases of 2 (Methyl Red), 4 (Ponceau BS) and 2.6 (Orange II)-fold compared to noninduced cells, respectively. Metabolites of Methyl Red isolated from induced cultures were identified as N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid through liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) analyses. In conclusion, our data demonstrate that AzoA from Ent. faecalis is capable of increasing the reduction of azo dyes in intact E. coli cells and that cytoplasmic azoreductase is involved in bacterial dye degradation in vivo.

Evidence for Significantly Enhancing Reduction of Azo Dyes in Escherichia coli by Expressed Cytoplasmic Azoreductase (AzoA) of Enterococcus faecalis

PubMed Central

Feng, Jinhui; Heinze, Thomas M.; Xu, Haiyan; Cerniglia, Carl E.; Chen, Huizhong

2018-01-01

Although cytoplasmic azoreductases have been purified and characterized from various bacteria, little evidence demonstrating that these azoreductases are directly involved in azo dye reduction in vivo is known. In order to evaluate the contribution of the enzyme to azo dye reduction in vivo, experiments were conducted to determine the effect of a recombinant cytoplasmic azoreductase (AzoA) from Enterococcus faecalis expressed in Escherichia coli on the rate of metabolism of Methyl Red, Ponceau BS and Orange II. The intact cells that contained IPTG induced AzoA had a higher rate of dye reduction with increases of 2 (Methyl Red), 4 (Ponceau BS) and 2.6 (Orange II)-fold compared to noninduced cells, respectively. Metabolites of Methyl Red isolated from induced cultures were identified as N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid through liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) analyses. In conclusion, our data demonstrate that AzoA from Ent. faecalis is capable of increasing the reduction of azo dyes in intact E. coli cells and that cytoplasmic azoreductase is involved in bacterial dye degradation in vivo. PMID:19663804

Formation of Carbamate Anions by the Gas-phase Reaction of Anilide Ions with CO2

NASA Astrophysics Data System (ADS)

Liu, Chongming; Nishshanka, Upul; Attygalle, Athula B.

2016-05-01

The anilide anion ( m/z 92) generated directly from aniline, or indirectly as a fragmentation product of deprotonated acetanilide, captures CO2 readily to form the carbamate anion ( m/z 136) in the collision cell, when CO2 is used as the collision gas in a tandem-quadrupole mass spectrometer. The gas-phase affinity of the anilide ion to CO2 is significantly higher than that of the phenoxide anion ( m/z 93), which adds to CO2 only very sluggishly. Our results suggest that the efficacy of CO2 capture depends on the natural charge density on the nitrogen atom, and relative nucleophilicity of the anilide anion. Generally, conjugate bases generated from aniline derivatives with proton affinities (PA) less than 350 kcal/mol do not tend to add CO2 to form gaseous carbamate ions. For example, the anion generated from p-methoxyaniline (PA = 367 kcal/mol) reacts significantly faster than that obtained from p-nitroaniline (PA = 343 kcal/mol). Although deprotonated p-aminobenzoic acid adds very poorly because the negative charge is now located primarily on the carboxylate group, it reacts more efficiently with CO2 if the carboxyl group is esterified. Moreover, mixture of CO2 and He as the collision gas was found to afford more efficient adduct formation than CO2 alone, or as mixtures made with nitrogen or argon, because helium acts as an effective "cooling" gas and reduces the internal energy of reactant ions.

Probing cathepsin K activity with a selective substrate spanning its active site.

PubMed

Lecaille, Fabien; Weidauer, Enrico; Juliano, Maria A; Brömme, Dieter; Lalmanach, Gilles

2003-10-15

The limited availability of highly selective cathepsin substrates seriously impairs studies designed to monitor individual cathepsin activities in biological samples. Among mammalian cysteine proteases, cathepsin K has a unique preference for a proline residue at P2, the primary determinant of its substrate specificity. Interestingly, congopain from Trypanosoma congolense also accommodates a proline residue in its S2 subsite. Analysis of a congopain model showed that amino acids forming its S2 subsite are identical with those of cathepsin K, except Leu67 which is replaced by a tyrosine residue in cathepsin K. Furthermore, amino acid residues of the congopain S2' binding pocket, which accepts a proline residue, are strictly identical with those of cathepsin K. Abz-HPGGPQ-EDN2ph [where Abz represents o-aminobenzoic acid and EDN2ph (=EDDnp) represents N -(2,4-dinitrophenyl)-ethylenediamine], a substrate initially developed for trypanosomal enzymes, was efficiently cleaved at the Gly-Gly bond by cathepsin K (kcat/ K(m)=426000 M(-1) x s(-1)). On the other hand, Abz-HPGGPQ-EDN2ph was resistant to hydrolysis by cathepsins B, F, H, L, S and V (20 nM enzyme concentration) and the Y67L (Tyr67-->Leu)/L205A cathepsin K mutant (20 nM), but still acted as a competitive inhibitor. Taken together, the selectivity of Abz-HPGGPQ-EDN2ph to cathepsin K primarily depends on the S2 and S2' subsite specificities of cathepsin K and the ionization state of histidine at P3. Whereas Abz-HPGGPQ-EDN2ph was hydrolysed by wild-type mouse fibroblast lysates, its hydrolysis was completely abolished in the cathepsin K-deficient samples, indicating that Abz-HPGGPQ-EDN2ph can be used to monitor selectively cathepsin K activity in physiological fluids and cell lysates.

Probing cathepsin K activity with a selective substrate spanning its active site.

PubMed Central

Lecaille, Fabien; Weidauer, Enrico; Juliano, Maria A; Brömme, Dieter; Lalmanach, Gilles

2003-01-01

The limited availability of highly selective cathepsin substrates seriously impairs studies designed to monitor individual cathepsin activities in biological samples. Among mammalian cysteine proteases, cathepsin K has a unique preference for a proline residue at P2, the primary determinant of its substrate specificity. Interestingly, congopain from Trypanosoma congolense also accommodates a proline residue in its S2 subsite. Analysis of a congopain model showed that amino acids forming its S2 subsite are identical with those of cathepsin K, except Leu67 which is replaced by a tyrosine residue in cathepsin K. Furthermore, amino acid residues of the congopain S2' binding pocket, which accepts a proline residue, are strictly identical with those of cathepsin K. Abz-HPGGPQ-EDN2ph [where Abz represents o-aminobenzoic acid and EDN2ph (=EDDnp) represents N -(2,4-dinitrophenyl)-ethylenediamine], a substrate initially developed for trypanosomal enzymes, was efficiently cleaved at the Gly-Gly bond by cathepsin K (kcat/ K(m)=426000 M(-1) x s(-1)). On the other hand, Abz-HPGGPQ-EDN2ph was resistant to hydrolysis by cathepsins B, F, H, L, S and V (20 nM enzyme concentration) and the Y67L (Tyr67-->Leu)/L205A cathepsin K mutant (20 nM), but still acted as a competitive inhibitor. Taken together, the selectivity of Abz-HPGGPQ-EDN2ph to cathepsin K primarily depends on the S2 and S2' subsite specificities of cathepsin K and the ionization state of histidine at P3. Whereas Abz-HPGGPQ-EDN2ph was hydrolysed by wild-type mouse fibroblast lysates, its hydrolysis was completely abolished in the cathepsin K-deficient samples, indicating that Abz-HPGGPQ-EDN2ph can be used to monitor selectively cathepsin K activity in physiological fluids and cell lysates. PMID:12837132

Covalent modification of reduced graphene oxide by means of diazonium chemistry and use as a drug-delivery system.

PubMed

Wei, Guangcheng; Yan, Miaomiao; Dong, Renhao; Wang, Dong; Zhou, Xiangzhu; Chen, Jingfei; Hao, Jingcheng

2012-11-12

Under acidic conditions, reduced graphene oxide (rGO) was functionalized with p-aminobenzoic acid, which formed the diazonium ions through the diazotization with a wet-chemical method. Surfactants or stabilizers were not applied during the diazotization. After the functionalized rGO was treated through mild sonication in aqueous solution, these functionalized rGO sheets were less than two layers, which was determined by atomic force microscopy (AFM) imaging. The water solubility of functionalized rGO after the introduction of polyethyleneimine (PEI) was improved significantly; it was followed by covalent binding of folic acid (FA) molecules to the functionalized rGO to allow us to specifically target CBRH7919 cancer cells by using FA as a receptor. The loading and release behaviors of elsinochrome A (EA) and doxorubicin (DOX) on the functionalized rGO sheets were investigated. The EA loading ratio onto rGO-C(6)H(4)-CO-NH-PEI-NH-CO-FA (abbreviated rGO-PEI-FA, the weight ratio of drug loaded onto rGO-PEI-FA) was approximately 45.56 %, and that of DOX was approximately 28.62 %. It was interesting that the drug release from rGO-PEI-FA was pH- and salt-dependent. The results of cytotoxicity (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry (FCM) assays, as well as cell morphology observations) clearly showed that the concentration of rGO-PEI-FA as the drug-delivery composite should be less than 12.5 mg L(-1). The conjugation of DOX and rGO-PEI-FA can enhance the cancer-cell apoptosis effectively and can also push the cancer cells to the vulnerable G2 phase of the cell cycle, which is most sensitive and susceptible to damage by drugs or radiation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inhibition of poly(ADP-ribose) polymerase prevents allergen-induced asthma-like reaction in sensitized Guinea pigs.

PubMed

Suzuki, Ylenia; Masini, Emanuela; Mazzocca, Cosimo; Cuzzocrea, Salvatore; Ciampa, Anna; Suzuki, Hisanori; Bani, Daniele

2004-12-01

Poly(ADP-ribose) polymerase (PARP) plays an important role in tissue injury in conditions associated with oxidative stress and inflammation. Because asthma is a chronic inflammatory disorder of the airways, we designed the present experimental study to evaluate the effects of PARP inhibition on allergen-induced asthma-like reaction in ovalbumin-sensitized guinea pigs. Cough and dyspnea in response to ovalbumin aerosol were absent in naive guinea pigs, whereas they became severe in the sensitized animals. In the latter ones, ovalbumin aerosol also induced a rapid increase in PARP activity, bronchiolar constriction, pulmonary air space inflation, mast cell degranulation, poly(ADP-ribose) and nitrotyrosine immunostaining, myeloperoxidase activity, and malondialdehyde in lung tissue, as well as a rise in the amounts of nitrites and tumor necrosis factor-alpha in bronchoalveolar lavage fluid. Pretreatment with the PARP inhibitors 3-aminobenzamide (10 mg/kg b.wt.) or 5-aminoisoquinolinone (0.5 mg/kg b.wt.) given i.p. 3 h before ovalbumin challenge significantly reduced the severity of cough and the occurrence of dyspnea and delayed the onset of respiratory abnormalities. Both PARP inhibitors were also able to prevent the above morphological and biochemical changes of lung tissue or bronchoalveolar lavage fluid induced by ovalbumin challenge. Conversely, p-aminobenzoic acid, the inactive analog of 3-aminobenzamide, had no effects.

Electron detachment dissociation of fluorescently labeled sialylated oligosaccharides.

PubMed

Zhou, Wen; Håkansson, Kristina

2011-12-01

We explored the application of electron detachment dissociation (EDD) and infrared multiphoton dissociation (IRMPD) tandem mass spectrometry to fluorescently labeled sialylated oligosaccharides. Standard sialylated oligosaccharides and a sialylated N-linked glycan released from human transferrin were investigated. EDD yielded extensive glycosidic cleavages and cross-ring cleavages in all cases studied, consistently providing complementary structural information compared with infrared multiphoton dissociation. Neutral losses and satellite ions such as C-2H ions were also observed following EDD. In addition, we examined the influence of different fluorescent labels. The acidic label 2-aminobenzoic acid (2-AA) enhanced signal abundance in negative-ion mode. However, few cross-ring fragments were observed for 2-AA-labeled oligosaccharides. The neutral label 2-aminobenzamide (2-AB) resulted in more cross-ring cleavages compared with 2-AA-labeled species, but not as extensive fragmentation as for native oligosaccharides, likely resulting from altered negative charge locations from introduction of the fluorescent tag. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantitative investigations of xylose and arabinose substituents in hydroxypropylated and hydroxyvinylethylated arabinoxylans.

PubMed

Lorenz, Dominic; Knöpfle, Anna; Akil, Youssef; Saake, Bodo

2017-11-01

The chemical structures obtained by the modification of arabinoxylans with the cyclic carbonates propylene carbonate (PC) and 4-vinyl-1,3-dioxolan-2-one (VEC) with varying degrees of substitution were investigated. Therefore, a new analytical method was developed that is based on a microwave-assisted hydrolysis of the polysaccharides with trifluoroacetic acid and the reductive amination with 2-aminobenzoic acid. The peak assignment was achieved by HPLC-MS and the carbohydrate derivatives were quantified by HPLC-fluorescence. The obtained maximum molar substitution of PC-derivatized xylan (X HP ) was 1.8; the molar substitution of VEC-derivatized xylan (X HVE ) was 2.3. Investigations of xylose and arabinose based mono- and disubstituted derivatives revealed a preferred reaction of the cyclic carbonates with arabinose. Conversion rates were up to 2.4 times higher for monosubstitution and up to 3.0 times for disubstitution compared to xylose. Furthermore, the reaction with VEC was preferred due to higher reactivity of the newly introduced side chains. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biochemical and molecular characterization of an azoreductase from Staphylococcus aureus, a tetrameric NADPH-dependent flavoprotein

PubMed Central

Chen, Huizhong; Hopper, Sherryll L.; Cerniglia, Carl E.

2018-01-01

Azo dyes are a predominant class of colourants used in tattooing, cosmetics, foods and consumer products. A gene encoding NADPH-flavin azoreductase (Azo1) from the skin bacterium Staphylococcus aureus ATCC 25923 was identified and overexpressed in Escherichia coli. RT-PCR results demonstrated that the azo1 gene was constitutively expressed at the mRNA level in S. aureus. Azo1 was found to be a tetramer with a native molecular mass of 85 kDa containing four non-covalently bound FMN. Azo1 requires NADPH, but not NADH, as an electron donor for its activity. The enzyme was resolved to dimeric apoprotein by removing the flavin prosthetic groups using hydrophobic-interaction chromatography. The dimeric apoprotein was reconstituted on-column and in free stage with FMN, resulting in the formation of a fully functional native-like tetrameric enzyme. The enzyme cleaved the model azo dye 2-[4-(dimethylamino)phenylazo]benzoic acid (Methyl Red) into N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid. The apparent Km values for NADPH and Methyl Red substrates were 0·;074 and 0·057 mM, respectively. The apparent Vmax was 0·4 µM min−1 (mg protein)−1. Azo1 was also able to metabolize Orange II, Amaranth, Ponceau BS and Ponceau S azo dyes. Azo1 represents the first azoreductase to be identified and characterized from human skin microflora. PMID:15870453

Single tag for total carbohydrate analysis.

PubMed

Anumula, Kalyan Rao

2014-07-15

Anthranilic acid (2-aminobenzoic acid, 2-AA) has the remarkable property of reacting rapidly with every type of reducing carbohydrate. Reactivity of 2-AA with carbohydrates in aqueous solutions surpasses all other tags reported to date. This unique capability is attributed to the strategically located -COOH which accelerates Schiff base formation. Monosaccharides, oligosaccharides (N-, O-, and lipid linked and glycans in secretory fluids), glycosaminoglycans, and polysaccharides can be easily labeled with 2-AA. With 2-AA, labeling is simple in aqueous solutions containing proteins, peptides, buffer salts, and other ingredients (e.g., PNGase F, glycosidase, and transferase reaction mixtures). In contrast, other tags require relatively pure glycans for labeling in anhydrous dimethyl sulfoxide-acetic acid medium. Acidic conditions are known to cause desialylation, thus requiring a great deal of attention to sample preparation. Simpler labeling is achieved with 2-AA within 30-60 min in mild acetate-borate buffered solution. 2-AA provides the highest sensitivity and resolution in chromatographic methods for carbohydrate analysis in a simple manner. Additionally, 2-AA is uniquely qualified for quantitative analysis by mass spectrometry in the negative mode. Analyses of 2-AA-labeled carbohydrates by electrophoresis and other techniques have been reported. Examples cited here demonstrate that 2-AA is the universal tag for total carbohydrate analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

Influence of porous texture and surface chemistry on the CO₂ adsorption capacity of porous carbons: acidic and basic site interactions.

PubMed

Sánchez-Sánchez, Angela; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M D

2014-12-10

Doped porous carbons exhibiting highly developed porosity and rich surface chemistry have been prepared and subsequently applied to clarify the influence of both factors on carbon dioxide capture. Nanocasting was selected as synthetic route, in which a polyaramide precursor (3-aminobenzoic acid) was thermally polymerized inside the porosity of an SBA-15 template in the presence of different H3PO4 concentrations. The surface chemistry and the porous texture of the carbons could be easily modulated by varying the H3PO4 concentration and carbonization temperature. Porous texture was found to be the determinant factor on carbon dioxide adsorption at 0 °C, while surface chemistry played an important role at higher adsorption temperatures. We proved that nitrogen functionalities acted as basic sites and oxygen and phosphorus groups as acidic ones toward adsorption of CO2 molecules. Among the nitrogen functional groups, pyrrolic groups exhibited the highest influence, while the positive effect of pyridinic and quaternary functionalities was smaller. Finally, some of these N-doped carbons exhibit CO2 heats of adsorption higher than 42 kJ/mol, which make them excellent candidates for CO2 capture.

Analysis of fluorescently labeled glycosphingolipid-derived oligosaccharides following ceramide glycanase digestion and anthranilic acid labeling.

PubMed

Neville, David C A; Coquard, Virginie; Priestman, David A; te Vruchte, Danielle J M; Sillence, Daniel J; Dwek, Raymond A; Platt, Frances M; Butters, Terry D

2004-08-15

Interest in cellular glycosphingolipid (GSL) function has necessitated the development of a rapid and sensitive method to both analyze and characterize the full complement of structures present in various cells and tissues. An optimized method to characterize oligosaccharides released from glycosphingolipids following ceramide glycanase digestion has been developed. The procedure uses the fluorescent compound anthranilic acid (2-aminobenzoic acid; 2-AA) to label oligosaccharides prior to analysis using normal-phase high-performance liquid chromatography. The labeling procedure is rapid, selective, and easy to perform and is based on the published method of Anumula and Dhume [Glycobiology 8 (1998) 685], originally used to analyze N-linked oligosaccharides. It is less time consuming than a previously published 2-aminobenzamide labeling method [Anal. Biochem. 298 (2001) 207] for analyzing GSL-derived oligosaccharides, as the fluorescent labeling is performed on the enzyme reaction mixture. The purification of 2-AA-labeled products has been improved to ensure recovery of oligosaccharides containing one to four monosaccharide units, which was not previously possible using the Anumula and Dhume post-derivatization purification procedure. This new approach may also be used to analyze both N- and O-linked oligosaccharides.

Electrochemical preparation of polyaniline-polypyrrole solid-phase microextraction coating and its application in the GC determination of several esters.

PubMed

Zhao, Shasha; Wu, Mian; Zhao, Faqiong; Zeng, Baizhao

2013-12-15

A novel polyaniline-polypyrrole (PANI-PPY) composite film coated stainless steel wire was prepared by cyclic voltammetry. Firstly, PANI was electrodeposited on a stainless steel wire from a solution containing 0.1 M aniline and 1M HNO3, after the PANI coating was dried in air PPY was electrodeposited on it from a solution containing 0.1 M pyrrole and 0.1 M p-methylbenzene sulfonic acid. The resulting PANI-PPY fiber showed reticulate structure and had large specific surface area. When it was used for the headspace solid-phase microextraction of several esters (i.e. methyl anthranilate, ethyl-o-aminobenzoate, dimethyl phthalate, methyl laurate, and diethyl phthalate), followed by gas chromatographic determination, it presented higher extraction capability in comparison with PPY and PANI coatings. Under the optimized conditions, the linear ranges were 0.07-300 μg L(-1) and the detection limits were 0.05-0.38 μg L(-1) for different esters. The PANI-PPY fiber also showed high durability, after being used for about 160 times its extraction capacity only changed a little. The proposed method was successfully applied to the determination of these esters in real samples and the recoveries were 90-102%. © 2013 Elsevier B.V. All rights reserved.

Novel furosemide cocrystals and selection of high solubility drug forms.

PubMed

Goud, N Rajesh; Gangavaram, Swarupa; Suresh, Kuthuru; Pal, Sharmistha; Manjunatha, Sulur G; Nambiar, Sudhir; Nangia, Ashwini

2012-02-01

Furosemide was screened in cocrystallization experiments with pharmaceutically acceptable coformer molecules to discover cocrystals of improved physicochemical properties, that is high solubility and good stability. Eight novel equimolar cocrystals of furosemide were obtained by liquid-assisted grinding with (i) caffeine, (ii) urea, (iii) p-aminobenzoic acid, (iv) acetamide, (v) nicotinamide, (vi) isonicotinamide, (vii) adenine, and (viii) cytosine. The product crystalline phases were characterized by powder x-ray diffraction, differential scanning calorimetry, infrared, Raman, near IR, and (13) C solid-state NMR spectroscopy. Furosemide-caffeine was characterized as a neutral cocrystal and furosemide-cytosine an ionic salt by single crystal x-ray diffraction. The stability of furosemide-caffeine, furosemide-adenine, and furosemide-cytosine was comparable to the reference drug in 10% ethanol-water slurry; there was no evidence of dissociation of the cocrystal to furosemide for up to 48 h. The other five cocrystals transformed to furosemide within 24 h. The solubility order for the stable forms is furosemide-cytosine > furosemide-adenine > furosemide-caffeine, and their solubilities are approximately 11-, 7-, and 6-fold higher than furosemide. The dissolution rates of furosemide cocrystals were about two times faster than the pure drug. Three novel furosemide compounds of higher solubility and good phase stability were identified in a solid form screen. Copyright © 2011 Wiley Periodicals, Inc.

Biodegradation of methyl red by Bacillus sp. strain UN2: decolorization capacity, metabolites characterization, and enzyme analysis.

PubMed

Zhao, Ming; Sun, Peng-Fei; Du, Lin-Na; Wang, Guan; Jia, Xiao-Ming; Zhao, Yu-Hua

2014-05-01

Azo dyes are recalcitrant and refractory pollutants that constitute a significant menace to the environment. The present study is focused on exploring the capability of Bacillus sp. strain UN2 for application in methyl red (MR) degradation. Effects of physicochemical parameters (pH of medium, temperature, initial concentration of dye, and composition of the medium) were studied in detail. The suitable pH and temperature range for MR degradation by strain UN2 were respectively 7.0-9.0 and 30-40 °C, and the optimal pH value and temperature were respectively 8.0 and 35 °C. Mg(2+) and Mn(2+) (1 mM) were found to significantly accelerate the MR removal rate, while the enhancement by either Fe(3+) or Fe(2+) was slight. Under the optimal degradation conditions, strain UN2 exhibited greater than 98 % degradation of the toxic azo dye MR (100 ppm) within 30 min. Analysis of samples from decolorized culture flasks confirmed biodegradation of MR into two prime metabolites: N,N'dimethyl-p-phenyle-nediamine and 2-aminobenzoic acid. A study of the enzymes responsible for the biodegradation of MR, in the control and cells obtained during (10 min) and after (30 min) degradation, showed a significant increase in the activities of azoreductase, laccase, and NADH-DCIP reductase. Furthermore, a phytotoxicity analysis demonstrated that the germination inhibition was almost eliminated for both the plants Triticum aestivum and Sorghum bicolor by MR metabolites at 100 mg/L concentration, yet the germination inhibition of parent dye was significant. Consequently, the high efficiency of MR degradation enables this strain to be a potential candidate for bioremediation of wastewater containing MR.

Genetic heterogeneity among slow acetylator N-acetyltransferase 2 phenotypes in cryopreserved human hepatocytes.

PubMed

Doll, Mark A; Hein, David W

2017-07-01

Genetic polymorphisms in human N-acetyltransferase 2 (NAT2) modify the metabolism of numerous drugs and carcinogens. These genetic polymorphisms modify both drug efficacy and toxicity and cancer risk associated with carcinogen exposure. Previous studies have suggested phenotypic heterogeneity among different NAT2 slow acetylator genotypes. NAT2 phenotype was investigated in vitro and in situ in samples of human hepatocytes obtained from various NAT2 slow and intermediate NAT2 acetylator genotypes. NAT2 gene dose response (NAT2*5B/*5B > NAT2*5B/*6A > NAT2*6A/*6A) was observed towards the N-acetylation of the NAT2-specific drug sulfamethazine by human hepatocytes both in vitro and in situ. N-acetylation of 4-aminobiphenyl, an arylamine carcinogen substrate for both N-acetyltransferase 1 and NAT2, showed the same trend both in vitro and in situ although the differences were not significant (p > 0.05). The N-acetylation of the N-acetyltransferase 1-specific substrate p-aminobenzoic acid did not follow this trend. In comparisons of NAT2 intermediate acetylator genotypes, differences in N-acetylation between NAT2*4/*5B and NAT2*4/*6B hepatocytes were not observed in vitro or in situ towards any of these substrates. These results further support phenotypic heterogeneity among NAT2 slow acetylator genotypes, consistent with differential risks of drug failure or toxicity and cancer associated with carcinogen exposure.

Non-stabilized nucleophiles in Cu-catalysed dynamic kinetic asymmetric allylic alkylation

NASA Astrophysics Data System (ADS)

You, Hengzhi; Rideau, Emeline; Sidera, Mireia; Fletcher, Stephen P.

2015-01-01

The development of new reactions forming asymmetric carbon-carbon bonds has enabled chemists to synthesize a broad range of important carbon-containing molecules, including pharmaceutical agents, fragrances and polymers. Most strategies to obtain enantiomerically enriched molecules rely on either generating new stereogenic centres from prochiral substrates or resolving racemic mixtures of enantiomers. An alternative strategy--dynamic kinetic asymmetric transformation--involves the transformation of a racemic starting material into a single enantiomer product, with greater than 50 per cent maximum yield. The use of stabilized nucleophiles (pKa < 25, where Ka is the acid dissociation constant) in palladium-catalysed asymmetric allylic alkylation reactions has proved to be extremely versatile in these processes. Conversely, the use of non-stabilized nucleophiles in such reactions is difficult and remains a key challenge. Here we report a copper-catalysed dynamic kinetic asymmetric transformation using racemic substrates and alkyl nucleophiles. These nucleophiles have a pKa of >=50, more than 25 orders of magnitude more basic than the nucleophiles that are typically used in such transformations. Organometallic reagents are generated in situ from alkenes by hydrometallation and give highly enantioenriched products under mild reaction conditions. The method is used to synthesize natural products that possess activity against tuberculosis and leprosy, and an inhibitor of para-aminobenzoate biosynthesis. Mechanistic studies indicate that the reaction proceeds through a rapidly isomerizing intermediate. We anticipate that this approach will be a valuable complement to existing asymmetric catalytic methods.

2-Pyridylfuran: a new fluorescent tag for the analysis of carbohydrates.

PubMed

Cai, Zhi Peng; Hagan, Andrew Kevin; Wang, Mao Mao; Flitsch, Sabine Lahja; Liu, Li; Voglmeir, Josef

2014-05-20

We herein report the use of 1,3-di(2-pyridyl)-1,3-propanedione (DPPD) as a fluorogenic labeling reagent for sugars. Reaction of DPPD with the anomeric carbon affords a fluorescent 2-pyridylfuran (2-PF) moiety that permits the sensitive HPLC-based detection of monosaccharides. 2-PF-labeled monosaccharides can be easily separated and analyzed from mixtures thereof, and the reported protocol compares favorably with established labeling reagents such as 2-aminobenzoic acid (2-AA) and 1-phenyl-3-methyl-5-pyrazolone (PMP), ultimately allowing subfemtomole detection of the galactose-derived product. Furthermore, we demonstrate the application of DPPD in the labeling of monosaccharides in complex biological matrices such as blood and milk samples. We envisage that DPPD will prove to be an excellent choice of labeling reagent in monosaccharide and carbohydrate analysis.

Stable Isotope Quantitative N-Glycan Analysis by Liquid Separation Techniques and Mass Spectrometry.

PubMed

Mittermayr, Stefan; Albrecht, Simone; Váradi, Csaba; Millán-Martín, Silvia; Bones, Jonathan

2017-01-01

Liquid phase separation analysis and subsequent quantitation remains a challenging task for protein-derived oligosaccharides due to their inherent structural complexity and diversity. Incomplete resolution or co-detection of multiple glycan species complicates peak area-based quantitation and associated statistical analysis when optical detection methods are used. The approach outlined herein describes the utilization of stable isotope variants of commonly used fluorescent tags that allow for mass-based glycan identification and relative quantitation following separation by liquid chromatography (LC) or capillary electrophoresis (CE). Comparability assessment of glycoprotein-derived oligosaccharides is performed by derivatization with commercially available isotope variants of 2-aminobenzoic acid or aniline and analysis by LC- and CE-mass spectrometry. Quantitative information is attained from the extracted ion chromatogram/electropherogram ratios generated from the light and heavy isotope clusters.

Analysis of O-glycans as 9-fluorenylmethyl derivatives and its application to the studies on glycan array.

PubMed

Yamada, Keita; Hirabayashi, Jun; Kakehi, Kazuaki

2013-03-19

A method is proposed for the analysis of O-glycans as 9-fluorenylmethyl (Fmoc) derivatives. After releasing the O-glycans from the protein backbone in the presence of ammonia-based media, the glycosylamines thus formed are conveniently labeled with Fmoc-Cl and analyzed by HPLC and MALDI-TOF MS after easy purification. Fmoc labeled O-glycans showed 3.5 times higher sensitivities than those labeled with 2-aminobenzoic acid in fluorescent detection. Various types of O-glycans having sialic acids, fucose, and/or sulfate residues were successfully labeled with Fmoc and analyzed by HPLC and MALDI-TOF MS. The method was applied to the comprehensive analysis of O-glycans expressed on MKN45 cells (human gastric adenocarcinoma). In addition, Fmoc-derivatized O-glycans were easily converted to free hemiacetal or glycosylamine-form glycans that are available for fabrication of glycan array and neoglycoproteins. To demonstrate the availability of our methods, we fabricate the glycan array with Fmoc labeled glycans derived from mucin samples and cancer cells. The model studies using the glycan array showed clear interactions between immobilized glycans and some lectins.

Production and analysis of organic acids in hairy-root cultures of Isatis indigotica Fort. (indigo woad).

PubMed

Xu, Tiefeng; Zhang, Lei; Sun, Xiaofen; Zhang, Hanming; Tang, Kexuan

2004-02-01

Hairy roots were induced from both cotyledon and hypocotyl explants of Isatis indigotica Fort. (indigo woad) through transformation with Agrobaterium rhizogenes strain A4, R1601 and ATCC15834. The results showed that the cotyledons were the preferred explants to hypocotyls and A4 was the most suitable A. rhizogenes strain for the transformation and induction of hairy roots of I. indigotica. High-voltage paper electrophoresis (HVPE) analysis demonstrated the production of mannopine in hairy roots and confirmed the successful transfer of Ri T-DNA (root-inducing transferred DNA) of A. rhizogenes into the I. indigotica genome. Five organic acids, namely CPQ [3-(2-carboxyphenol)-4(3 H )-quinazolinone], syringic acid, salicylic acid, benzoic acid and 2-aminobenzoic acid, which were considered as main antiviral components of I. indigotica, were detected in natural roots, hairy roots and liquid media with high-performance capillary electrophoresis. The results showed CPQ production in hairy roots was significantly higher than that in natural roots. Our results also revealed that all the five organic acids could be excreted from hairy roots into liquid media, and the concentrations of organic acids in the liquid media paralleled those in hairy roots. The hairy roots of I. indigotica grew fast and showed an S-shaped growth curve that reached its apex on the day 24 of culture with a 20-fold increase in fresh weight compared with the starting inoculums. The accumulation of the two organic acids CPQ and syringic acid in liquid media paralleled the growth of hairy roots. MS [Murashige, T. and Skoog, F. (1962) Physiol. Plant. 15, 473-497] medium or half-strength MS medium supplemented with 30 g/l maltose was found to be best for hairy-root culture and accumulation of CPQ.

Analysis of UV filters in tap water and other clean waters in Spain.

PubMed

Díaz-Cruz, M Silvia; Gago-Ferrero, Pablo; Llorca, Marta; Barceló, Damià

2012-03-01

The present paper describes the development of a method for the simultaneous determination of five hormonally active UV filters namely benzophenone-3 (BP3), 3-(4-methylbenzylidene) camphor (4MBC), 2-ethylhexyl 4-(dimethylamino) benzoate (OD-PABA), 2-ethylhexyl 4-methoxycinnamate (EHMC) and octocrylene (OC) by means of solid-phase extraction and gas chromatography-electron impact ionization-mass spectrometry. Under optimized conditions, this methodology achieved low method limits of detection (needed for clean waters, especially drinking water analysis), between 0.02 and 8.42 ng/L, and quantitative recovery rates higher than 73% in all cases. Inter- and intraday precision for all compounds were lower than 7% and 11%, respectively. The optimized methodology was applied to perform the first survey of UV absorbing compounds in tap water from the metropolitan area and the city of Barcelona (Catalonia, Spain). In addition, other types of clean water matrices (mineral bottled water, well water and tap water treated with an ion-exchange resin) were investigated as well. Results evidenced that all the UV filters investigated were detected in the water samples analyzed. The compounds most frequently found were EHMC and OC. Maximum concentrations reached in tap water were 290 (BP3), 35 (4MBC), 110 (OD-PABA), 260 (EHMC), and 170 ng/L (OC). This study constitutes the first evidence of the presence of UV filter residues in tap water in Europe.

Solubility of pharmaceuticals: A comparison between SciPharma, a PC-SAFT-based approach, and NRTL-SAC

NASA Astrophysics Data System (ADS)

Bouillot, Baptiste; Spyriouni, Theodora; Teychené, Sébastien; Biscans, Béatrice

2017-04-01

The solubility of seven pharmaceutical compounds (paracetamol, benzoic acid, 4-aminobenzoic acid, salicylic acid, ibuprofen, naproxen and temazepam) in pure and mixed solvents as a function of temperature is calculated with SciPharma, a semi-empirical approach based on PC-SAFT, and the NRTL-SAC model. To conduct a fair comparison between the approaches, the parameters of the compounds were regressed against the same solubility data, chosen to account for hydrophilic, polar and hydrophobic interactions. Only these solubility data were used by both models for predicting solubility in other pure and mixed solvents for which experimental data were available for comparison. A total of 386 pure solvent data points were used for the comparison comprising one or more temperatures per solvent. SciPharma is found to be more accurate than NRTL-SAC on the pure solvent data used especially in the description of the temperature dependence. This is due to the appropriate parameterization of the pharmaceuticals and the temperature-dependent description of the activity coefficient in PC-SAFT. The solubility in mixed solvents is predicted satisfactorily with SciPharma. NRTL-SAC tends to overestimate the solubility in aqueous solutions of alcohols or shows invariable solubility with composition in other cases.

Comparison of isocratic retention models for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

PubMed

Česla, Petr; Vaňková, Nikola; Křenková, Jana; Fischer, Jan

2016-03-18

In this work, we have investigated retention of maltooligosaccharides and their fluorescent derivatives in hydrophilic interaction liquid chromatography using four different stationary phases. The non-derivatized maltooligosaccharides (maltose to maltoheptaose) and their derivatives with 2-aminobenzoic acid, 2-aminobenzamide, 2-aminopyridine and 8-aminonaphthalene-1,3,6-trisulfonic acid were analyzed on silica gel, aminopropyl silica, amide (carbamoyl-bonded silica) and ZIC-HILIC zwitterionic sulfobetain bonded phase. The partitioning of the analytes between the bulk mobile phase and adsorbed water-rich layer, polar and ionic interactions of analytes with stationary phase have been evaluated and compared. The effects of the mobile phase additives (0.1% (v/v) of acetic acid and ammonium acetate in concentration range 5-30 mmol L(-1)) on retention were described. The suitability of different models for prediction of retention was tested including linear solvent strength model, quadratic model, mixed-mode model, and empirical Neue-Kuss model. The mixed-mode model was extended to the parameter describing the contribution of monomeric glucose unit to the retention of non-derivatized and derivatized maltooligosaccharides, which was used for evaluation of contribution of both, oligosaccharide backbone and end-group to retention. Copyright © 2016 Elsevier B.V. All rights reserved.

Allergic contact dermatitis from ethyl chloride and benzocaine.

PubMed

Carazo, Juan Luis Anguita; Morera, Blanca Sáenz de San Pedro; Colom, Luis Palacios; Gálvez Lozano, José Manuel

2009-01-01

Ethyl chloride (EC) or chloroethane (C2H5Cl) is a volatile halogenated hydrocarbon. Reports of contact sensitivity to this gas are infrequent considering its widespread use as a local anesthetic, and it may have a relatively low sensitization potential. Benzocaine is another local anesthetic derivative of the ethyl ester of para-aminobenzoic acid, previously reported as a causative agent of delayed hypersensitivity reactions. We present a patient who developed a generalized itching dermatitis after the application of a medical aerosol containing EC, as well as facial angioedema and tongue swelling after the local application of benzocaine. Patch-test results were positive for EC "as is" (++), benzocaine 5% in petrolatum (++), and caine mix (+++) at 96 hours (day 4). The possibility of cross-sensitization between both drugs would not have been chemically plausible. We report the first published clinical case of contact allergic dermatitis from two chemically unrelated local anesthetics (EC and benzocaine) in the same patient.

Metabolism of azo dyes by human skin microbiota

PubMed Central

Stingley, Robin L.; Zou, Wen; Heinze, Thomas M.; Chen, Huizhong; Cerniglia, Carl E.

2018-01-01

Reduction of Methyl Red (MR) and Orange II (Or II) by 26 human skin bacterial species was monitored by a rapid spectrophotometric assay. The analysis indicated that skin bacteria, representing the genera Staphylococcus, Corynebacterium, Micrococcus, Dermacoccus and Kocuria, were able to reduce MR by 74–100 % in 24 h, with only three species unable to reduce completely the dye in that time. Among the species tested, only Corynebacterium xerosis was unable to reduce Or II to any degree by 24 h, and only Staphylococcus delphini, Staphylococcus sciuri subsp. sciuri and Pseudomonas aeruginosa were able to reduce completely this dye within 24 h. MR reduction started with early-exponential growth in Staphylococcus aureus and Staphylococcus epidermidis, and around late-exponential/early-stationary growth in P. aeruginosa. Reduction of Or II, Ponceau S and Ponceau BS started during late-exponential/early-stationary growth for all three species. Using liquid chromatography/electrospray ionization mass spectrometry analyses, MR metabolites produced by Staph. aureus, Staph. epidermidis and P. aeruginosa were identified as N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid. Searches of available genomic and proteomic data revealed that at least four of the staphylococci in this study, Staphylococcus haemolyticus, Staph. epidermidis, Staphylococcus cohnii and Staphylococcus saprophyticus, have hypothetical genes with 77, 76, 75 and 74 % sequence identity to azo1 encoding an azoreductase from Staph. aureus and hypothetical proteins with 82, 80, 72 and 74 % identity to Azo1, respectively. In addition, Staphylococcus capitis has a protein with 79 % identity to Azo1. Western analysis detected proteins similar to Azo1 in all the staphylococci tested, except Staph. delphini, Staph. sciuri subsp. sciuri and Staphylococcus auricularis. The data presented in this report will be useful in the risk assessment process for evaluation of public exposure to products containing these dyes. PMID:19729456

Metabolism of azo dyes by human skin microbiota.

PubMed

Stingley, Robin L; Zou, Wen; Heinze, Thomas M; Chen, Huizhong; Cerniglia, Carl E

2010-01-01

Reduction of Methyl Red (MR) and Orange II (Or II) by 26 human skin bacterial species was monitored by a rapid spectrophotometric assay. The analysis indicated that skin bacteria, representing the genera Staphylococcus, Corynebacterium, Micrococcus, Dermacoccus and Kocuria, were able to reduce MR by 74-100 % in 24 h, with only three species unable to reduce completely the dye in that time. Among the species tested, only Corynebacterium xerosis was unable to reduce Or II to any degree by 24 h, and only Staphylococcus delphini, Staphylococcus sciuri subsp. sciuri and Pseudomonas aeruginosa were able to reduce completely this dye within 24 h. MR reduction started with early-exponential growth in Staphylococcus aureus and Staphylococcus epidermidis, and around late-exponential/early-stationary growth in P. aeruginosa. Reduction of Or II, Ponceau S and Ponceau BS started during late-exponential/early-stationary growth for all three species. Using liquid chromatography/electrospray ionization mass spectrometry analyses, MR metabolites produced by Staph. aureus, Staph. epidermidis and P. aeruginosa were identified as N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid. Searches of available genomic and proteomic data revealed that at least four of the staphylococci in this study, Staphylococcus haemolyticus, Staph. epidermidis, Staphylococcus cohnii and Staphylococcus saprophyticus, have hypothetical genes with 77, 76, 75 and 74 % sequence identity to azo1 encoding an azoreductase from Staph. aureus and hypothetical proteins with 82, 80, 72 and 74 % identity to Azo1, respectively. In addition, Staphylococcus capitis has a protein with 79 % identity to Azo1. Western analysis detected proteins similar to Azo1 in all the staphylococci tested, except Staph. delphini, Staph. sciuri subsp. sciuri and Staphylococcus auricularis. The data presented in this report will be useful in the risk assessment process for evaluation of public exposure to products containing these dyes.

Studies on molecular structure, vibrational spectra and molecular docking analysis of 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate

NASA Astrophysics Data System (ADS)

Suresh, D. M.; Amalanathan, M.; Hubert Joe, I.; Bena Jothy, V.; Diao, Yun-Peng

2014-09-01

The molecular structure, vibrational analysis and molecular docking analysis of the 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate (MDDNAB) molecule have been carried out using FT-IR and FT-Raman spectroscopic techniques and DFT method. The equilibrium geometry, harmonic vibrational wave numbers, various bonding features have been computed using density functional method. The calculated molecular geometry has been compared with experimental data. The detailed interpretation of the vibrational spectra has been carried out by using VEDA program. The hyper-conjugative interactions and charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The simulated FT-IR and FT-Raman spectra satisfactorily coincide with the experimental spectra. The PES and charge analysis have been made. The molecular docking was done to identify the binding energy and the Hydrogen bonding with the cancer protein molecule.

Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

NASA Astrophysics Data System (ADS)

McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

2016-05-01

Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides.

PubMed

McMillen, Chelsea L; Wright, Patience M; Cassady, Carolyn J

2016-05-01

Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

[Improvement of local lymph node assay for cosmetics safety evaluation].

PubMed

Liu, Zhen; Liu, Junping; Wang, Fei; Xu, Guifeng; Hou, Juan; Wan, Xuying; Zhang, Tianbao

2009-09-01

To improve the local lymph node assay (LLNA) as an alternative method to detect chemicals for both sensitization and irritation. The following chemicals: one negative control: 4-Aminobenzoic Acid, three sensitizers: 2,4-dinitrochlorobenzene (DNCB), Hexyl cinnamic aldehyde (HCA), 2-Aminophenol (2-APC) and two irritations: potassium hydroxide (KOH), sodium lauryl sulphate (SLS) were selected. According to the normal LLNA, groups of female Balb/c mice were treated with test solutions. The thickness of each ear was measured and each auricle was weighed. On the sixth day, the bilateral draining auricular lymph nodes were excised and weighed. The single cell suspensions were prepared, the lymphocyte were counted and the proliferations of lymph cells were detected by cell counting kit-8 (CCK-8). Significant increase in ear thickness and weight were found in groups of KOH, SLS and DNCB (above 0.5%) (P < 0.05), which could be considered as irritants, whereas irritation were not found in 2-APC and HCA. In the allergic test, three sensitizers showed positive, but different sensitivity were found among each index. HCA, DNCB and 2-APC could all obviously augment the weight of lymph node and the lymphocyte count in different groups (P < 0.05). Conspicuous proliferation of lymphocyte were found in DNCB (all group), HCA (above the middle dose) and 2-APC (high dose) by CCK-8. The reformed LLNA using auricle thickness and weighing as observed markers for irritation, and using lymph nodes weighing and proliferation of lymphocyte as observed markers for sensitization, could evaluate both sensitization and irritation at the same time.

Cathepsin K: a cysteine protease with unique kinin-degrading properties

PubMed Central

2004-01-01

Taking into account a previous report of an unidentified enzyme from macrophages acting as a kininase, the ability of cysteine proteases to degrade kinins has been investigated. Wild-type fibroblast lysates from mice, by contrast with cathepsin K-deficient lysates, hydrolysed BK (bradykinin), and released two metabolites, BK-(1–4) and BK-(5–9). Cathepsin K, but not cathepsins B, H, L and S, cleaved kinins at the Gly4–Phe5 bond and the bradykinin-mimicking substrate Abz (o-aminobenzoic acid)-RPPGFSPFR-3-NO2-Tyr (3-nitrotyrosine) more efficiently (pH 6.0: kcat/Km=12500 mM−1·s−1; pH 7.4: kcat/Km=6930 mM−1·s−1) than angiotensin-converting enzyme hydrolysed BK. Conversely Abz-RPPGFSPFR-3-NO2-Tyr was not cleaved by the Y67L (Tyr67→Leu)/L205A (Leu205→Ala) cathepsin K mutant, indicating that kinin degradation mostly depends on the S2 substrate specificity. Kininase activity was further evaluated on bronchial smooth muscles. BK, but not its metabolites BK(1-4) and BK(5-9), induced a dose-dependent contraction, which was abolished by Hoe140, a B2-type receptor antagonist. Cathepsin K impaired BK-dependent contraction of normal and chronic hypoxic rats, whereas cathepsins B and L did not. Taking together vasoactive properties of kinins and the potency of cathepsin K to modulate BK-dependent contraction of smooth muscles, the present data support the notion that cathepsin K may act as a kininase, a unique property among mammalian cysteine proteases. PMID:15265002

Double-blind comparison of two types of benzocaine lozenges for the treatment of acute pharyngitis.

PubMed

Busch, Regina; Graubaum, Hans-Joachim; Grünwald, Jörg; Schmidt, Mathias

2010-01-01

In a reference-controlled double-blind trial in patients with acute pharyngitis the effects of a newly developed lozenge containing 8 mg of benzocaine (p-aminobenzoic acid ethyl ester, CAS 94-09-7) were compared with those of an identically dosed commercial pastille. 246 patients were randomized to receive either the lozenges (group A, n = 123) or the pastilles (group B, n = 123). Each patient took a total of six doses within 12 h according to the double-dummy principle, with each single dose spaced by 2 h. The primary parameter was the assessment of the responder rate with = 50 % pain relief within 15 min post application. Further parameters included the relative relief of pain in the course of the study and the tolerability of the formulation. After application of the first unit the comparison of groups yielded very similar and statistically not differing results for efficacy in both groups, with responder rates of 25.2 % and 22.0 % in groups A and B, respectively. One adverse drug reaction was observed in group B (burning and tingling feeling on the tongue), which, however, did not lead to discontinuation of study participation. In all other cases tolerability was stated to be "good to very good". The application of the benzocaine lozenges was statistically non-inferior to the use of the pastilles.

Sol-gel chemical sensors for surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Lee, Vincent Y.; Farquharson, Stuart; Kwon, Hueong-Chan; Shahriari, Mahmoud R.; Rainey, Petrie M.

1999-02-01

Surface-enhanced Raman spectroscopy (SERS) promises to be one of the most sensitive methods for chemical detection. Unfortunately, the inability of SERS to perform quantitative chemical analysis has slowed its general use in laboratories. This is largely due to the difficulty of manufacturing either active surfaces that yield reproducible enhancements, or surfaces that are capable of reversible chemical adsorption, or both. In an effort to meet this need, we have developed metal-doped sol-gels that provide surface-enhancement of Raman scattering. The porous silica network offers a unique environment for stabilizing SER active metal particles and the high surface area increases the interaction between the analyte and metal particles. This eliminates the need to concentrate the analyte on the surface by evaporating the solvent. The sol-gel is easily coated on a variety of surfaces, such as fiber optics, glass slides, or glass tubing, and can be designed into sample flow systems. Here we present the development of both gold- and silver-doped sol-gels, which have been used to coat the inside walls of glass sample vials for SERS applications. The performance of the metal-doped sol-gels was evaluated using p-aminobenzoic acid, to establish enhancement factors, detection limits, dynamic response range, reversibility, reproducibility, and suitability to commercial spectrometers. Measurements of trace chemicals, such as adenine and cocaine, are also presented.

Statistical process control of cocrystallization processes: A comparison between OPLS and PLS.

PubMed

Silva, Ana F T; Sarraguça, Mafalda Cruz; Ribeiro, Paulo R; Santos, Adenilson O; De Beer, Thomas; Lopes, João Almeida

2017-03-30

Orthogonal partial least squares regression (OPLS) is being increasingly adopted as an alternative to partial least squares (PLS) regression due to the better generalization that can be achieved. Particularly in multivariate batch statistical process control (BSPC), the use of OPLS for estimating nominal trajectories is advantageous. In OPLS, the nominal process trajectories are expected to be captured in a single predictive principal component while uncorrelated variations are filtered out to orthogonal principal components. In theory, OPLS will yield a better estimation of the Hotelling's T 2 statistic and corresponding control limits thus lowering the number of false positives and false negatives when assessing the process disturbances. Although OPLS advantages have been demonstrated in the context of regression, its use on BSPC was seldom reported. This study proposes an OPLS-based approach for BSPC of a cocrystallization process between hydrochlorothiazide and p-aminobenzoic acid monitored on-line with near infrared spectroscopy and compares the fault detection performance with the same approach based on PLS. A series of cocrystallization batches with imposed disturbances were used to test the ability to detect abnormal situations by OPLS and PLS-based BSPC methods. Results demonstrated that OPLS was generally superior in terms of sensibility and specificity in most situations. In some abnormal batches, it was found that the imposed disturbances were only detected with OPLS. Copyright © 2017 Elsevier B.V. All rights reserved.

Occurrence of organic UV filters and metabolites in lebranche mullet (Mugil liza) from Brazil.

PubMed

Molins-Delgado, Daniel; Muñoz, Ramón; Nogueira, Sylvia; Alonso, Mariana B; Torres, João Paulo; Malm, Olaf; Ziolli, Roberta Lourenço; Hauser-Davis, Rachel Ann; Eljarrat, Ethel; Barceló, Damià; Díaz-Cruz, M Silvia

2018-03-15

UV filters (UV-Fs) constitute a heterogeneous group of chemicals used as protection against the effects of UV radiation, widely used in all sort of goods and ubiquitous in the environment. The presence of these chemicals in fish is a matter of concern, because many UV-Fs display hormonal activity. In this study, muscle, gills, and liver from 11 Mugil liza individuals from the highly urbanized Guanabara Bay (Rio de Janeiro, Brazil) were analysed in order to detect eight UV-Fs and metabolites (4-dihydroxybenzophenone [BP1] (2-hydroxy-4-methoxybenzophenone [BP3], 4-methylbenzylidiene camphor [4MBC], ethylhexyl methoxycinnamate [EHMC], ethylhexyl dimethyl p-aminobenzoic acid [ODPABA], octocrylene [OC], 4-hydroxybenzophenone [4HB], and 4,4'-dihydroxybenzophenone [4DHB]) using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results showed that both target UV-Fs and metabolites were ubiquitous in the analysed tissues. Lower concentrations were observed in muscle and gills (3.07-31.6ngg -1 dry weight (dw)), whereas in liver significant amounts of metabolites (5.47-451ngg -1 dw) were present. With the concentrations determined in the fish, an estimation of the daily intake revealed that consumption of muscle in the diet represent from 0.3 to 15.2ng UV-Fs (kg body weight -1 ) d -1 , higher than those reported in fish for selected persistent organic pollutants (POPs). Copyright © 2017 Elsevier B.V. All rights reserved.

Dual gas-diffusion membrane- and mediatorless dihydrogen/air-breathing biofuel cell operating at room temperature

NASA Astrophysics Data System (ADS)

Xia, Hong-qi; So, Keisei; Kitazumi, Yuki; Shirai, Osamu; Nishikawa, Koji; Higuchi, Yoshiki; Kano, Kenji

2016-12-01

A membraneless direct electron transfer (DET)-type dihydrogen (H2)/air-breathing biofuel cell without any mediator was constructed wherein bilirubin oxidase from Myrothecium verrucaria (BOD) and membrane-bound [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F (MBH) were used as biocatalysts for the cathode and the anode, respectively, and Ketjen black-modified water proof carbon paper (KB/WPCC) was used as an electrode material. The KB/WPCC surface was modified with 2-aminobenzoic acid and p-phenylenediamine, respectively, to face the positively charged electron-accepting site of BOD and the negatively charged electron-donating site of MBH to the electrode surface. A gas-diffusion system was employed for the electrodes to realize high-speed substrate supply. As result, great improvement in the current density of O2 reduction with BOD and H2 reduction with MBH were realized at negatively and postively charged surfaces, respectively. Gas diffusion system also suppressed the oxidative inactivation of MBH at high electrode potentials. Finally, based on the improved bioanode and biocathode, a dual gas-diffusion membrane- and mediatorless H2/air-breathing biofuel cell was constructed. The maximum power density reached 6.1 mW cm-2 (at 0.72 V), and the open circuit voltage was 1.12 V using 1 atm of H2 gas as a fuel at room temperature and under passive and quiescent conditions.

Analysis of N-acetylaminosugars by CE: a comparative derivatization study.

PubMed

Rustighi, Isabella; Campa, Cristiana; Rossi, Marco; Semeraro, Sabrina; Vetere, Amedeo; Gamini, Amelia

2009-08-01

N-linked or O-linked glycans derived from glycoprotein processing carry, an N-acetylglucosamine or an N-acetylgalactosamine respectively, at their reducing termini. The presence of the N-acetylamino group on C-2 of reducing sugar residues has been reported to hamper the derivatization reaction with a chromophore at the anomeric centre. In this paper N-acetyllactosamine, N-acetylglucosamine, N-acetylgalactosamine and several other neutral monosaccharides are coupled to three different dyes (4-aminobenzonitrile, 2-aminopyridine, 2-aminobenzoic acid (2-AA)) by reductive amination and analysed by CE with UV detection. The 2-AA derivatives showed the lowest concentration detection limits, varying approximately in the 2-3 muM range for the saccharides tested including the N-acetamido ones. The possibility to separate and detect with the same sensitivity ten 2-AA-labelled monosaccharides mainly found in mammalian or plant glycoproteins in a single CE run is highlighted. The analysis has been carried out in less than 25 min using the borate-complexation method in CZE mode. The influence of the strength of the acid used as catalyst in the chemical modification of the sugars with 2-AA is also shortly addressed.

Design, synthesis, characterization and computational docking studies of novel sulfonamide derivatives.

PubMed

Saleem, Hira; Maryam, Arooma; Bokhari, Saleem Ahmed; Ashiq, Ayesha; Rauf, Sadaf Abdul; Khalid, Rana Rehan; Qureshi, Fahim Ashraf; Siddiqi, Abdul Rauf

2018-01-01

This study reports three novel sulfonamide derivatives 4-Chloro-N-[(4-methylphenyl) sulphonyl]-N-propyl benzamide ( 1A ), N-(2-hydroxyphenyl)-4-methyl benzene sulfonamide ( 1B ) and 4-methyl-N-(2-nitrophenyl) benzene sulfonamide ( 1C ). The compounds were synthesised from starting material 4-methylbenzenesulfonyl chloride and their structure was studied through 1 H-NMR and 13 C-NMR spectra. Computational docking was performed to estimate their binding energy against bacterial p -amino benzoic acid (PABA) receptor, the dihydropteroate synthase (DHPS). The derivatives were tested in vitro for their antimicrobial activity against Gram+ and Gram- bacteria including E. coli, B. subtilis, B. licheniformis and B. linen. 1A was found active only against B. linen ; 1B was effective against E. coli, B. subtilis and B. linen whereas 1C showed activity against E. coli, B. licheniformis and B. linen . 1C showed maximum activity with minimum inhibitory concentration (MIC) of 50, 100 and 150 µg/mL against E. coli, B. licheniformis and B. linen respectively. 1C exhibited maximum affinity to DHPS with binding free energy of -8.1 kcal/mol. It enriched in the top 0.5 % of a library of 7663 compounds, ranked in order of their binding affinity against DHPS. 1C was followed by 1B which showed a moderate to low level MIC of 100, 250 and 150 µg/mL against E. coli, B. subtilis and B. linen respectively, whereas 1A showed a moderate level MIC of 100 µg/mL but only against B. linen . These derivatives may thus serve as potential anti-bacterial alternatives against resistant pathogens.

Survey of the Anaerobic Biodegradation Potential of Organic Chemicals in Digesting Sludge

PubMed Central

Battersby, Nigel S.; Wilson, Valerie

1989-01-01

The degradation potential of 77 organic chemicals under methanogenic conditions was examined with an anaerobic digesting sludge from the United Kingdom. Degradation was assessed in terms of net total gas (CH4 plus CO2) produced, expressed as a percentage of the theoretical production (ThGP). The compounds tested were selected from various chemical groups and included substituted phenols and benzoates, pesticides, phthalic acid esters, homocyclic and heterocyclic ring compounds, glycols, and monosubstituted benzenes. The results obtained were in good agreement with published surveys of biodegradability in U.S. digesting sludges and other methanogenic environments. In general, the presence of chloro or nitro groups inhibited anaerobic gas production, while carboxyl and hydroxyl groups facilitated biodegradation. The relationship between substituent position and susceptibility to methanogenic degradation was compound dependent. The following chemicals were completely degraded (≥80% ThGP) at a concentration of 50 mg of carbon per liter: phenol, 2-aminophenol, 4-cresol, catechol, sodium benzoate, 4-aminobenzoic acid, 3-chlorobenzoic acid, phthalic acid, ethylene glycol, diethylene glycol, triethylene glycol, sodium stearate, and quinoline. 3-Cresol, 4-chlorobenzoic acid, dimethyl phthalate, and pyridine were partially degraded. Although the remaining chemicals tested were either persistent or toxic, their behavior may differ at more environmentally realistic chemical-to-biomass ratios. Our findings suggest that biodegradability assessments made with sludge from one source can be extrapolated to sludge from another source with a reasonable degree of confidence and should help in predicting the fate of an organic chemical during the anaerobic digestion of sewage sludge. PMID:16347851

Characterization of kallikrein-related peptidase 4 glycosylations

PubMed Central

Yamakoshi, Yasuo; Yamakoshi, Fumiko; Hu, Jan C-C.; Simmer, James P.

2012-01-01

Kallikrein-related peptidase 4 (KLK4) is a glycosylated serine protease that functions in the maturation (hardening) of dental enamel. Pig and mouse KLK4 contain three potential N-glycosylation sites. We isolated KLK4 from developing pig and mouse molars and characterized their N-glycosylations. N-glycans were enzymatically released by digestion with N-glycosidase F and fluorescently labeled with 2-aminobenzoic acid. Normal-phase high-performance liquid chromatography (NP-HPLC) revealed N-glycans with no, or with one, two, or three sialic acid attachments in pig KLK4 and with no, or with one or two sialic acid attachments in mouse KLK4. The labeled N-glycans were digested with sialidase to generate the asialo N-glycan cores that were fractionated by reverse-phase HPLC, and their retention times were compared with similarly labeled glycan standards. The purified cores were characterized by mass spectrometric and monosaccharide composition analyses. We determined that pig and mouse KLK4 have NA2 and NA2F biantennary N-glycan cores. The pig triantennary core is NA3. The mouse triantennary core is NA3 with a fucose connected by an α1–6 linkage, indicating that it is attached to the first N-acetyglucosamine (NA3F). We conclude that pig KLK4 has NA2, NA2F, and NA3 N-glycan cores with no, or with one, two, or three sialic acids. Mouse KLK4 has NA2, NA2F, and NA3F N-glycan cores with no, or with one or two sialic acids. PMID:22243251

Characterization of kallikrein-related peptidase 4 glycosylations.

PubMed

Yamakoshi, Yasuo; Yamakoshi, Fumiko; Hu, Jan C-C; Simmer, James P

2011-12-01

Kallikrein-related peptidase 4 (KLK4) is a glycosylated serine protease that functions in the maturation (hardening) of dental enamel. Pig and mouse KLK4 contain three potential N-glycosylation sites. We isolated KLK4 from developing pig and mouse molars and characterized their N-glycosylations. N-glycans were enzymatically released by digestion with N-glycosidase F and fluorescently labeled with 2-aminobenzoic acid. Normal-phase high-performance liquid chromatography (NP-HPLC) revealed N-glycans with no, or with one, two, or three sialic acid attachments in pig KLK4 and with no, or with one or two sialic acid attachments in mouse KLK4. The labeled N-glycans were digested with sialidase to generate the asialo N-glycan cores that were fractionated by reverse-phase HPLC, and their retention times were compared with similarly labeled glycan standards. The purified cores were characterized by mass spectrometric and monosaccharide composition analyses. We determined that pig and mouse KLK4 have NA2 and NA2F biantennary N-glycan cores. The pig triantennary core is NA3. The mouse triantennary core is NA3 with a fucose connected by an α1-6 linkage, indicating that it is attached to the first N-acetyglucosamine (NA3F). We conclude that pig KLK4 has NA2, NA2F, and NA3 N-glycan cores with no, or with one, two, or three sialic acids. Mouse KLK4 has NA2, NA2F, and NA3F N-glycan cores with no, or with one or two sialic acids. © 2011 Eur J Oral Sci.

Prediction of gradient retention data for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

PubMed

Vaňková, Nikola; Česla, Petr

2017-02-17

In this work, we have investigated the predictive properties of mixed-mode retention model and oligomeric mixed-mode model, taking into account the contribution of monomeric units to the retention, in hydrophilic interaction liquid chromatography. The gradient retention times of native maltooligosaccharides and their fluorescent derivatives were predicted in the oligomeric series with number of monomeric glucose units in the range from two to seven. The maltooligosaccharides were separated on a packed column with carbamoyl-bonded silica stationary phase and 15 gradient profiles with different initial and final mobile phase composition were used with the gradient times 5; 7.5 and 10min. The predicted gradient retention times were compared for calculations based on isocratic retention data and gradient retention data, which provided better accuracy of the results. By comparing two different mobile phase additives, the more accurate retention times were predicted in mobile phases containing ammonium acetate. The acidic derivatives, prepared by reaction of an oligosaccharide with 2-aminobenzoic acid or 8-aminonaphthalene-1,3,6-trisulfonic acid, provided more accurate predictions of the retention data in comparison to native oligosaccharides or their neutral derivatives. The oligomeric mixed-mode model allowed prediction of gradient retention times using only one gradient profile, which significantly speeded-up the method development. Copyright © 2017 Elsevier B.V. All rights reserved.

Is energy pooling necessary in ultraviolet matrix-assisted laser desorption/ionization?

PubMed

Lin, Hou-Yu; Song, Botao; Lu, I-Chung; Hsu, Kuo-Tung; Liao, Chih-Yu; Lee, Yin-Yu; Tseng, Chien-Ming; Lee, Yuan-Tseh; Ni, Chi-Kung

2014-01-15

Energy pooling has been suggested as the key process for generating the primary ions during ultraviolet matrix-assisted laser desorption/ionization (UV-MALDI). In previous studies, decreases in fluorescence quantum yields as laser fluence increased for 2-aminobenzoic acid, 2,5-dihydroxybenzoic acid (2,5-DHB), and 3-hydroxypicolinic acid were used as evidence of energy pooling. This work extends the research to other matrices and addresses whether energy pooling is a universal property in UV-MALDI. Energy pooling was investigated in a time-resolved fluorescence experiment by using a short laser pulse (355 nm, 20 ps pulse width) for excitation and a streak camera (1 ps time resolution) for fluorescence detection. The excited-state lifetime of 2,5-DHB decreased with increases in laser fluence. This suggests that a reaction occurs between two excited molecules, and that energy pooling may be one of the possible reactions. However, the excited-state lifetime of 2,4,6-trihydroxyacetophenone (THAP) did not change with increases in laser fluence. The upper limit of the energy pooling rate constant for THAP is estimated to be approximately 100-500 times smaller than that of 2,5-DHB. The small energy pooling rate constant for THAP indicates that the potential contribution of the energy pooling mechanism to the generation of THAP matrix primary ions should be reconsidered. Copyright © 2013 John Wiley & Sons, Ltd.

Studies on molecular structure, vibrational spectra and molecular docking analysis of 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate.

PubMed

Suresh, D M; Amalanathan, M; Joe, I Hubert; Jothy, V Bena; Diao, Yun-Peng

2014-09-15

The molecular structure, vibrational analysis and molecular docking analysis of the 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate (MDDNAB) molecule have been carried out using FT-IR and FT-Raman spectroscopic techniques and DFT method. The equilibrium geometry, harmonic vibrational wave numbers, various bonding features have been computed using density functional method. The calculated molecular geometry has been compared with experimental data. The detailed interpretation of the vibrational spectra has been carried out by using VEDA program. The hyper-conjugative interactions and charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The simulated FT-IR and FT-Raman spectra satisfactorily coincide with the experimental spectra. The PES and charge analysis have been made. The molecular docking was done to identify the binding energy and the Hydrogen bonding with the cancer protein molecule. Copyright © 2014 Elsevier B.V. All rights reserved.

A Paleolithic-type diet results in iodine deficiency: a 2-year randomized trial in postmenopausal obese women.

PubMed

Manousou, S; Stål, M; Larsson, C; Mellberg, C; Lindahl, B; Eggertsen, R; Hulthén, L; Olsson, T; Ryberg, M; Sandberg, S; Nyström, H F

2018-01-01

Different diets are used for weight loss. A Paleolithic-type diet (PD) has beneficial metabolic effects, but two of the largest iodine sources, table salt and dairy products, are excluded. The objectives of this study were to compare 24-h urinary iodine concentration (24-UIC) in subjects on PD with 24-UIC in subjects on a diet according to the Nordic Nutrition Recommendations (NNR) and to study if PD results in a higher risk of developing iodine deficiency (ID), than NNR diet. A 2-year prospective randomized trial in a tertiary referral center where healthy postmenopausal overweight or obese women were randomized to either PD (n=35) or NNR diet (n=35). Dietary iodine intake, 24-UIC, 24-h urinary iodine excretion (24-UIE), free thyroxin (FT4), free triiodothyronine (FT3) and thyrotropin (TSH) were measured at baseline, 6 and 24 months. Completeness of urine sampling was monitored by para-aminobenzoic acid and salt intake by urinary sodium. At baseline, median 24-UIC (71.0 μg/l) and 24-UIE (134.0 μg/d) were similar in the PD and NNR groups. After 6 months, 24-UIC had decreased to 36.0 μg/l (P=0.001) and 24-UIE to 77.0 μg/d (P=0.001) in the PD group; in the NNR group, levels were unaltered. FT4, TSH and FT3 were similar in both groups, except for FT3 at 6 months being lower in PD than in NNR group. A PD results in a higher risk of developing ID, than a diet according to the NNR. Therefore, we suggest iodine supplementation should be considered when on a PD.

Synthesis and characterization of covalently bound benzocaine graphite oxide derivative

NASA Astrophysics Data System (ADS)

Kabbani, Ahmad; Kabbani, Mohamad; Safadi, Khadija

2015-09-01

Graphite oxide (GO) derived materials include chemically functionalize or reduced graphene oxide (exfoliated from GO) sheets, assembled paper-like forms , and graphene-based composites GO consists of intact graphitic regions interspersed with sp3-hybridized carbons containing hydroxyl and epoxide functional groups on the top and bottom surfaces of each sheet and sp2-hybridized carbons containing carboxyl and carbonyl groups mostly at the sheet edges. Hence, GO is hydrophilic and readily disperses in water to form stable colloidal suspensions Due to the attached oxygen functional groups, GO was used to prepare different derivatives which result in some physical and chemical properties that are dramatically different from their bulk counterparts .The present work discusses the covalent cross linking of graphite oxide to benzocaine or ethyl ester of para-aminobenzoic acid,structure I,used in many over-the-counter ointment drug.Synthesis is done via diazotization of the amino group.The product is characterized via IR,Raman, X-ray photoelectron spectroscopy as well as electron microscopy.

The Impact of Using Different Methods to Assess Completeness of 24-Hour Urine Collection on Estimating Dietary Sodium.

PubMed

Wielgosz, Andreas; Robinson, Christopher; Mao, Yang; Jiang, Ying; Campbell, Norm R C; Muthuri, Stella; Morrison, Howard

2016-06-01

The standard for population-based surveillance of dietary sodium intake is 24-hour urine testing; however, this may be affected by incomplete urine collection. The impact of different indirect methods of assessing completeness of collection on estimated sodium ingestion has not been established. The authors enlisted 507 participants from an existing community study in 2009 to collect 24-hour urine samples. Several methods of assessing completeness of urine collection were tested. Mean sodium intake varied between 3648 mg/24 h and 7210 mg/24 h depending on the method used. Excluding urine samples collected for longer or shorter than 24 hours increased the estimated urine sodium excretion, even when corrections for the variation in timed collections were applied. Until an accurate method of indirectly assessing completeness of urine collection is identified, the gold standard of administering para-aminobenzoic acid is recommended. Efforts to ensure participants collect complete urine samples are also warranted. ©2015 Wiley Periodicals, Inc.

A review on cholinesterase inhibitors for Alzheimer's disease.

PubMed

Anand, Preet; Singh, Baldev

2013-04-01

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is characterized by the deficits in the cholinergic system and deposition of beta amyloid (Aβ) in the form of neurofibrillary tangles and amyloid plaques. Since the cholinergic system plays an important role in the regulation of learning and memory processes, it has been targetted for the design of anti-Alzheimer's drugs. Cholinesterase inhibitors enhance cholinergic transmission directly by inhibiting the enzyme acetylcholinesterase (AChE) which hydrolyses acetylcholine. Furthermore, it has been also demonstrated that both acetylcholinesterase and butrylcholinesterase (BuChE) play an important role in Aβ-aggregation during the early stages of senile plaque formation. Therefore, AChE and BuChE inhibition have been documented as critical targets for the effective management of AD by an increase in the availability of acetylcholine in the brain regions and decrease in the Aβ deposition. This review discusses the different classes of cholinesterase inhibitors including tacrine, donepezil, rivastigmine, galantamine, xanthostigmine, para-aminobenzoic acid, coumarin, flavonoid, and pyrrolo-isoxazole analogues developed for the treatment of AD.

Ab initio random structure searching of organic molecular solids: assessment and validation against experimental data.

PubMed

Zilka, Miri; Dudenko, Dmytro V; Hughes, Colan E; Williams, P Andrew; Sturniolo, Simone; Franks, W Trent; Pickard, Chris J; Yates, Jonathan R; Harris, Kenneth D M; Brown, Steven P

2017-10-04

This paper explores the capability of using the DFT-D ab initio random structure searching (AIRSS) method to generate crystal structures of organic molecular materials, focusing on a system (m-aminobenzoic acid; m-ABA) that is known from experimental studies to exhibit abundant polymorphism. Within the structural constraints selected for the AIRSS calculations (specifically, centrosymmetric structures with Z = 4 for zwitterionic m-ABA molecules), the method is shown to successfully generate the two known polymorphs of m-ABA (form III and form IV) that have these structural features. We highlight various issues that are encountered in comparing crystal structures generated by AIRSS to experimental powder X-ray diffraction (XRD) data and solid-state magic-angle spinning (MAS) NMR data, demonstrating successful fitting for some of the lowest energy structures from the AIRSS calculations against experimental low-temperature powder XRD data for known polymorphs of m-ABA, and showing that comparison of computed and experimental solid-state NMR parameters allows different hydrogen-bonding motifs to be discriminated.

Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes.

PubMed

Bhattacharjee, Chira R; Goswami, Pankaj; Pramanik, Harun A R; Paul, Pradip C; Mondal, Paritosh

2011-05-01

Two new mixed-ligand iron(III) complexes, [Fe(L(n))(acac)(C(2)H(5)OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac)(3)] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H(2)L(1)) or 2-aminobenzoic acid (H(2)L(2)). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L(n))(acac)X] (n=1, 2; X=Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, (1)H and (13)C NMR spectroscopy. Room temperature magnetic susceptibility measurements (μ(eff)∼5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (ΔE(p)>100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential (E(1/2)) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level. Copyright © 2011 Elsevier B.V. All rights reserved.

Genetic variation in Dip5, an amino acid permease, and Pdr5, a multiple drug transporter, regulates glyphosate resistance in S. cerevisiae.

PubMed

Rong-Mullins, Xiaoqing; Ravishankar, Apoorva; McNeal, Kirsten A; Lonergan, Zachery R; Biega, Audrey C; Creamer, J Philip; Gallagher, Jennifer E G

2017-01-01

S. cerevisiae from different environments are subject to a wide range of selective pressures, whether intentional or by happenstance. Chemicals classified by their application, such as herbicides, fungicides and antibiotics, can affect non-target organisms. First marketed as RoundUp™, glyphosate is the most widely used herbicide. In plants, glyphosate inhibits EPSPS, of the shikimate pathway, which is present in many organisms but lacking in mammals. The shikimate pathway produces chorismate which is the precursor to all the aromatic amino acids, para-aminobenzoic acid, and Coenzyme Q10. Crops engineered to be resistant to glyphosate contain a homolog of EPSPS that is not bound by glyphosate. Here, we show that S. cerevisiae has a wide-range of glyphosate resistance. Sequence comparison between the target proteins, i.e., the plant EPSPS and the yeast orthologous protein Aro1, predicted that yeast would be resistant to glyphosate. However, the growth variation seen in the subset of yeast tested was not due to polymorphisms within Aro1, instead, it was caused by genetic variation in an ABC multiple drug transporter, Pdr5, and an amino acid permease, Dip5. Using genetic variation as a probe into glyphosate response, we uncovered mechanisms that contribute to the transportation of glyphosate in and out of the cell. Taking advantage of the natural genetic variation within yeast and measuring growth under different conditions that would change the use of the shikimate pathway, we uncovered a general transport mechanism of glyphosate into eukaryotic cells.

Genetic variation in Dip5, an amino acid permease, and Pdr5, a multiple drug transporter, regulates glyphosate resistance in S. cerevisiae

PubMed Central

McNeal, Kirsten A.; Lonergan, Zachery R.; Biega, Audrey C.; Creamer, J. Philip

2017-01-01

S. cerevisiae from different environments are subject to a wide range of selective pressures, whether intentional or by happenstance. Chemicals classified by their application, such as herbicides, fungicides and antibiotics, can affect non-target organisms. First marketed as RoundUp™, glyphosate is the most widely used herbicide. In plants, glyphosate inhibits EPSPS, of the shikimate pathway, which is present in many organisms but lacking in mammals. The shikimate pathway produces chorismate which is the precursor to all the aromatic amino acids, para-aminobenzoic acid, and Coenzyme Q10. Crops engineered to be resistant to glyphosate contain a homolog of EPSPS that is not bound by glyphosate. Here, we show that S. cerevisiae has a wide-range of glyphosate resistance. Sequence comparison between the target proteins, i.e., the plant EPSPS and the yeast orthologous protein Aro1, predicted that yeast would be resistant to glyphosate. However, the growth variation seen in the subset of yeast tested was not due to polymorphisms within Aro1, instead, it was caused by genetic variation in an ABC multiple drug transporter, Pdr5, and an amino acid permease, Dip5. Using genetic variation as a probe into glyphosate response, we uncovered mechanisms that contribute to the transportation of glyphosate in and out of the cell. Taking advantage of the natural genetic variation within yeast and measuring growth under different conditions that would change the use of the shikimate pathway, we uncovered a general transport mechanism of glyphosate into eukaryotic cells. PMID:29155836

Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

PubMed

DeNichilo, Mark O; Panagopoulos, Vasilios; Rayner, Timothy E; Borowicz, Romana A; Greenwood, John E; Evdokiou, Andreas

2015-05-01

Myeloperoxidase and eosinophil peroxidase are heme-containing enzymes often physically associated with fibrotic tissue and cancer in various organs, without any direct involvement in promoting fibroblast recruitment and extracellular matrix (ECM) biosynthesis at these sites. We report herein novel findings that show peroxidase enzymes possess a well-conserved profibrogenic capacity to stimulate the migration of fibroblastic cells and promote their ability to secrete collagenous proteins to generate a functional ECM both in vitro and in vivo. Mechanistic studies conducted using cultured fibroblasts show that these cells are capable of rapidly binding and internalizing both myeloperoxidase and eosinophil peroxidase. Peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl 4-hydroxylase-dependent manner that does not require ascorbic acid. This response was blocked by the irreversible myeloperoxidase inhibitor 4-amino-benzoic acid hydrazide, indicating peroxidase catalytic activity is essential for collagen biosynthesis. These results suggest that peroxidase enzymes, such as myeloperoxidase and eosinophil peroxidase, may play a fundamental role in regulating the recruitment of fibroblast and the biosynthesis of collagen ECM at sites of normal tissue repair and fibrosis, with enormous implications for many disease states where infiltrating inflammatory cells deposit peroxidases. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

4,4′-Bipyridinium bis(perchlorate)–4-aminobenzoic acid–4,4′-bipyridine–water (1/4/2/2)

PubMed Central

Meng, Qun-Hui; Han, Lu; Hou, Jian-Dong; Luo, Yi-Fan; Zeng, Rong-Hua

2009-01-01

In the structure of the title compound, C10H10N2 2+·2ClO4 −·4C7H7NO2·2C10H8N2·2H2O, the 4,4′-bipyridinium cation has a crystallographically imposed centre of symmetry. The cation is linked by N—H⋯N hydrogen bonds to adjacent 4,4′-bipyridine mol­ecules, which in turn inter­act via O—H⋯N hydrogen bonds with 4-amino­benzoic acid mol­ecules, forming chains running parallel to [30]. The chains are further connected into a three-dimensional network by N—H⋯O and O—H⋯O hydrogen-bonding inter­actions involving the perchlorate anion, the water mol­ecules and the 4-amino­benzoic acid mol­ecules. In addition, π–π stacking inter­actions with centroid–centroid distances ranging from 3.663 (6) to 3.695 (6) Å are present. The O atoms of the perchlorate anion are disordered over two sets of positions, with refined site occupancies of 0.724 (9) and 0.276 (9). PMID:21581593

Small scale affinity purification and high sensitivity reversed phase nanoLC-MS N-glycan characterization of mAbs and fusion proteins.

PubMed

Higel, Fabian; Seidl, Andreas; Demelbauer, Uwe; Sörgel, Fritz; Frieß, Wolfgang

2014-01-01

N-glycosylation is a complex post-translational modification with potential effects on the efficacy and safety of therapeutic proteins and known influence on the effector function of biopharmaceutical monoclonal antibodies (mAbs). Comprehensive characterization of N-glycosylation is therefore important in biopharmaceutical development. In early development, e.g. during pool or clone selection, however, only minute protein amounts of multiple samples are available for analytics. High sensitivity and high throughput methods are thus needed. An approach based on 96-well plate sample preparation and nanoLC-MS of 2- anthranilic acid or 2-aminobenzoic acid (AA) labeled N-glycans for the characterization of biopharmaceuticals in early development is reported here. With this approach, 192 samples can be processed simultaneously from complex matrices (e.g., cell culture supernatant) to purified 2-AA glycans, which are then analyzed by reversed phase nanoLC-MS. Attomolar sensitivity has been achieved by use of nanoelectrospray ionization, resulting in detailed glycan maps of mAbs and fusion proteins that are exemplarily shown in this work. Reproducibility, robustness and linearity of the approach are demonstrated, making use in a routine manner during pool or clone selection possible. Other potential fields of application, such as glycan biomarker discovery from serum samples, are also presented.

Small scale affinity purification and high sensitivity reversed phase nanoLC-MS N-glycan characterization of mAbs and fusion proteins

PubMed Central

Higel, Fabian; Seidl, Andreas; Demelbauer, Uwe; Sörgel, Fritz; Frieß, Wolfgang

2014-01-01

N-glycosylation is a complex post-translational modification with potential effects on the efficacy and safety of therapeutic proteins and known influence on the effector function of biopharmaceutical monoclonal antibodies (mAbs). Comprehensive characterization of N-glycosylation is therefore important in biopharmaceutical development. In early development, e.g. during pool or clone selection, however, only minute protein amounts of multiple samples are available for analytics. High sensitivity and high throughput methods are thus needed. An approach based on 96-well plate sample preparation and nanoLC-MS of 2- anthranilic acid or 2-aminobenzoic acid (AA) labeled N-glycans for the characterization of biopharmaceuticals in early development is reported here. With this approach, 192 samples can be processed simultaneously from complex matrices (e.g., cell culture supernatant) to purified 2-AA glycans, which are then analyzed by reversed phase nanoLC-MS. Attomolar sensitivity has been achieved by use of nanoelectrospray ionization, resulting in detailed glycan maps of mAbs and fusion proteins that are exemplarily shown in this work. Reproducibility, robustness and linearity of the approach are demonstrated, making use in a routine manner during pool or clone selection possible. Other potential fields of application, such as glycan biomarker discovery from serum samples, are also presented. PMID:24848368

Microscale Measurements of Michaelis-Menten Constants of Neuraminidase with Nanogel Capillary Electrophoresis for the Determination of the Sialic Acid Linkage.

PubMed

Gattu, Srikanth; Crihfield, Cassandra L; Holland, Lisa A

2017-01-03

Phospholipid nanogels enhance the stability and performance of the exoglycosidase enzyme neuraminidase and are used to create a fixed zone of enzyme within a capillary. With nanogels, there is no need to covalently immobilize the enzyme, as it is physically constrained. This enables rapid quantification of Michaelis-Menten constants (K M ) for different substrates and ultimately provides a means to quantify the linkage (i.e., 2-3 versus 2-6) of sialic acids. The fixed zone of enzyme is inexpensive and easily positioned in the capillary to support electrophoresis mediated microanalysis using neuraminidase to analyze sialic acid linkages. To circumvent the limitations of diffusion during static incubation, the incubation period is reproducibly achieved by varying the number of forward and reverse passes the substrate makes through the stationary fixed zone using in-capillary electrophoretic mixing. A K M value of 3.3 ± 0.8 mM (V max , 2100 ± 200 μM/min) was obtained for 3'-sialyllactose labeled with 2-aminobenzoic acid using neuraminidase from Clostridium perfringens that cleaves sialic acid monomers with an α2-3,6,8,9 linkage, which is similar to values reported in the literature that required benchtop analyses. The enzyme cleaves the 2-3 linkage faster than the 2-6, and a K M of 2 ± 1 mM (V max , 400 ± 100 μM/min) was obtained for the 6'-sialyllactose substrate. An alternative neuraminidase selective for 2-3 sialic acid linkages generated a K M value of 3 ± 2 mM (V max , 900 ± 300 μM/min) for 3'-sialyllactose. With a knowledge of V max , the method was applied to a mixture of 2-3 and 2-6 sialyllactose as well as 2-3 and 2-6 sialylated triantennary glycan. Nanogel electrophoresis is an inexpensive, rapid, and simple alternative to current technologies used to distinguish the composition of 3' and 6' sialic acid linkages.

Microscale Measurements of Michaelis–Menten Constants of Neuraminidase with Nanogel Capillary Electrophoresis for the Determination of the Sialic Acid Linkage

PubMed Central

2016-01-01

Phospholipid nanogels enhance the stability and performance of the exoglycosidase enzyme neuraminidase and are used to create a fixed zone of enzyme within a capillary. With nanogels, there is no need to covalently immobilize the enzyme, as it is physically constrained. This enables rapid quantification of Michaelis–Menten constants (KM) for different substrates and ultimately provides a means to quantify the linkage (i.e., 2-3 versus 2-6) of sialic acids. The fixed zone of enzyme is inexpensive and easily positioned in the capillary to support electrophoresis mediated microanalysis using neuraminidase to analyze sialic acid linkages. To circumvent the limitations of diffusion during static incubation, the incubation period is reproducibly achieved by varying the number of forward and reverse passes the substrate makes through the stationary fixed zone using in-capillary electrophoretic mixing. A KM value of 3.3 ± 0.8 mM (Vmax, 2100 ± 200 μM/min) was obtained for 3′-sialyllactose labeled with 2-aminobenzoic acid using neuraminidase from Clostridium perfringens that cleaves sialic acid monomers with an α2-3,6,8,9 linkage, which is similar to values reported in the literature that required benchtop analyses. The enzyme cleaves the 2-3 linkage faster than the 2-6, and a KM of 2 ± 1 mM (Vmax, 400 ± 100 μM/min) was obtained for the 6′-sialyllactose substrate. An alternative neuraminidase selective for 2-3 sialic acid linkages generated a KM value of 3 ± 2 mM (Vmax, 900 ± 300 μM/min) for 3′-sialyllactose. With a knowledge of Vmax, the method was applied to a mixture of 2-3 and 2-6 sialyllactose as well as 2-3 and 2-6 sialylated triantennary glycan. Nanogel electrophoresis is an inexpensive, rapid, and simple alternative to current technologies used to distinguish the composition of 3′ and 6′ sialic acid linkages. PMID:27936604

Porcine dentin sialoprotein glycosylation and glycosaminoglycan attachments.

PubMed

Yamakoshi, Yasuo; Nagano, Takatoshi; Hu, Jan Cc; Yamakoshi, Fumiko; Simmer, James P

2011-02-03

Dentin sialophosphoprotein (Dspp) is a multidomain, secreted protein that is critical for the formation of tooth dentin. Mutations in DSPP cause inherited dentin defects categorized as dentin dysplasia type II and dentinogenesis imperfecta type II and type III. Dentin sialoprotein (Dsp), the N-terminal domain of dentin sialophosphoprotein (Dspp), is a highly glycosylated proteoglycan, but little is known about the number, character, and attachment sites of its carbohydrate moieties. To identify its carbohydrate attachment sites we isolated Dsp from developing porcine molars and digested it with endoproteinase Glu-C or pronase, fractionated the digestion products, identified fractions containing glycosylated peptides using a phenol sulfuric acid assay, and characterized the glycopeptides by N-terminal sequencing, amino acid analyses, or LC/MSMS. To determine the average number of sialic acid attachments per N-glycosylation, we digested Dsp with glycopeptidase A, labeled the released N-glycosylations with 2-aminobenzoic acid, and quantified the moles of released glycosylations by comparison to labeled standards of known concentration. Sialic acid was released by sialidase digestion and quantified by measuring β-NADH reduction of pyruvic acid, which was generated stoichiometrically from sialic acid by aldolase. To determine its forms, sialic acid released by sialidase digestion was labeled with 1,2-diamino-4,5-methyleneoxybenzene (DMB) and compared to a DMB-labeled sialic acid reference panel by RP-HPLC. To determine the composition of Dsp glycosaminoglycan (GAG) attachments, we digested Dsp with chondroitinase ABC and compared the chromotagraphic profiles of the released disaccharides to commercial standards. N-glycosylations were identified at Asn37, Asn77, Asn136, Asn155, Asn161, and Asn176. Dsp averages one sialic acid per N-glycosylation, which is always in the form of N-acetylneuraminic acid. O-glycosylations were tentatively assigned at Thr200, Thr216 and Thr316. Porcine Dsp GAG attachments were found at Ser238 and Ser250 and were comprised of chondroitin 6-sulfate and chondroitin 4-sulfate in a ratio of 7 to 3, respectively. The distribution of porcine Dsp posttranslational modifications indicate that porcine Dsp has an N-terminal domain with at least six N-glycosylations and a C-terminal domain with two GAG attachments and at least two O-glycosylations.

Congenic rats with higher arylamine N-acetyltransferase 2 activity exhibit greater carcinogen-induced mammary tumor susceptibility independent of carcinogen metabolism.

PubMed

Stepp, Marcus W; Doll, Mark A; Samuelson, David J; Sanders, Mary Ann G; States, J Christopher; Hein, David W

2017-03-31

Recent investigations suggest role(s) of human arylamine N-acetyltransferase 1 (NAT1) in breast cancer. Rat NAT2 is orthologous to human NAT1 and the gene products are functional homologs. We conducted in vivo studies using F344.WKY-Nat2 rapid/slow rats, congenic at rat Nat2 for high (rapid) and low (slow) arylamine N-acetyltransferase activity, to assess a possible role for rat NAT2 in mammary tumor susceptibility. Mammary carcinogens, methylnitrosourea (MNU) and 7,12-dimethylbenzanthracene (DMBA) neither of which is metabolized by N-acetyltransferase, were administered to assess mammary tumors. MNU was administered at 3 or 8 weeks of age. DMBA was administered at 8 weeks of age. NAT2 enzymatic activity and endogenous acetyl-coenzyme A (AcCoA) levels were measured in tissue samples and embryonic fibroblasts isolated from the congenic rats. Tumor latency was shorter in rapid NAT2 rats compared to slow NAT2 rats, with statistical significance for MNU administered at 3 and 8 weeks of age (p = 0.009 and 0.050, respectively). Tumor multiplicity and incidence were higher in rapid NAT2 rats compared to slow NAT2 rats administered MNU or DMBA at 8 weeks of age (MNU, p = 0.050 and 0.035; DMBA, p = 0.004 and 0.027, respectively). Recombinant rat rapid-NAT2, as well as tissue samples and embryonic fibroblasts derived from rapid NAT2 rats, catalyzed p-aminobenzoic acid N-acetyl transfer and folate-dependent acetyl-coenzyme A (AcCoA) hydrolysis at higher rates than those derived from rat slow-NAT2. Embryonic fibroblasts isolated from rapid NAT2 rats displayed lower levels of cellular AcCoA than slow NAT2 rats (p < 0.01). A novel role for rat NAT2 in mammary cancer was discovered unrelated to carcinogen metabolism, suggesting a role for human NAT1 in breast cancer.

Crystal and molecular structures of sixteen charge-assisted hydrogen bond-mediated diisopropylammonium salts from different carboxylic acids

NASA Astrophysics Data System (ADS)

Lin, Zhihao; Hu, Kaikai; Jin, Shouwen; Ding, Aihua; Wang, Yining; Dong, Lingfeng; Gao, Xingjun; Wang, Daqi

2017-10-01

Cocrystallization of the commonly available organic amine, diisopropylamine, with a series of carboxylic acids gave a total of sixteen molecular salts with the compositions: diisopropylaminium 2-methyl-2-phenoxypropanate [(Hdpa)+ · (mpa-), mpa- = 2-methyl-2-phenoxypropanoate] (1), diisopropylaminium 2-methyl-2-(naphthalen-2-yloxy)-propionate [(Hdpa)+ · (npa-), npa- = 2-methyl-2-(naphthalen-2-yloxy)-propionate] (2), diisopropylaminium indole-3-acetate [(Hdpa)+ · (iaa-), iaa- = indole-3-acetate] (3), diisopropylaminium 4-chlorophenoxyacetate [(Hdpa)+ · (cpa-), cpa- = 4-chlorophenoxyacetate] (4), diisopropylaminium 2,4-dichlorophenoxyacetate [(Hdpa)+ · (dcpa-), dcpa- = 2,4-dichlorophenoxyacetate] (5), diisopropylaminium 4-hydroxybenzoate [(Hdpa)+ · (hba-), hba- = 4-hydroxybenzoate] (6), diisopropylaminium 4-aminobenzoate [(Hdpa)+ · (aba-), aba- = 4-aminobenzoate] (7), tetra(diisopropylaminium) tetra(1-hydroxy-2-naphthoate) trihydrate [(Hdpa)44+ · (2-hnpa)44- · 3H2O, 2-hnpa = 1-hydroxy-2-naphthoate] (8), diisopropylaminium 2-hydroxy-3-naphthoate [(Hdpa)+ · (3-hnpa-), 3-hnpa- = 2-hydroxy-3-naphthoate] (9), diisopropylaminium 5-bromosalicylate [(Hdpa)+ · (bsa-), bsa- = 5-bromosalicylate] (10), diisopropylaminium 3,5-dinitrobenzoate [(Hdpa)+ · (dna-), dna- = 3,5-dinitrobenzoate] (11), diisopropylaminium 3,5-dinitrosalicylate [(Hdpa)+ · (3,5-dns-), 3,5-dns- = 3,5-dinitrosalicylate] (12), tetra(diisopropylaminium) bis(m-phthalate) monohydrate [(Hdpa+)4 · (mpta2-)2 · H2O, mpta2- = m-phthalate] (13), bis(diisopropylaminium) dihydrogen 1,2,3,4-butane tetracarboxylate [(Hdpa+)2 · (H2Bta2-), H2Bta2- = dihydrogen 1,2,3,4-butane tetracarboxylate] (14), bis(diisopropylaminium) mucate [(Hdpa+)2 · (muc2-), muc2- = mucate] (15), and diisopropylaminium hydrogen 1,2-phenylenediacetate [(Hdpa) · (Hpda-), Hpda- = hydrogen 1,2-phenylenediacetate] (16). The sixteen salts have been characterised by XRD technique, IR, and elemental analysis, and the melting points of all the salts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the sixteen investigated crystals the NH groups in the diisopropylamine are protonated when the carboxylic acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted Nsbnd H⋯O hydrogen bond formation between the ammonium and the deprotonated COOH groups. Except the Nsbnd H⋯O hydrogen bond, the Osbnd H⋯O hydrogen bonds (charge assisted or neutral) were also found at the salts 6, 8, 9, 10, 12, 13, 14, 15, and 16. Further analysis of the crystal packing of the salts indicated that a different family of additional CHsbnd O/CH2sbnd O/CH3sbnd O, CH-π/CH3-π, CH3-Cπ, N-π, and π-π associations contribute to the stabilization and expansion of the total structures. For the coexistence of the various weak interactions these structures adopted homo or hetero supramolecular synthons or both.

Development of a quantitative high-performance thin-layer chromatographic method for sucralose in sewage effluent, surface water, and drinking water.

PubMed

Morlock, Gertrud E; Schuele, Leonard; Grashorn, Sebastian

2011-05-13

Sucralose, a persistent chlorinated substance used as sweetener, can already be found in waste water, and various countries focused on the release of sucralose into the aquatic environment. A quantitative high-performance thin-layer chromatography (HPTLC) method, which is orthogonal to existing methods, was developed to analyze sucralose in water. After sample preparation, separation of up to 17 samples was performed in parallel on a HPTLC plate silica gel 60 F(254) with a mixture of isopropyl acetate, methanol and water (15:3:1, v/v/v) within 15 min. Due to the weak native UV absorption of sucralose (≤200 nm), various post-chromatographic derivatization reactions were compared to selectively detect sucralose in effluent and surface water matrices. Thereby p-aminobenzoic acid reagent was discovered as a new derivatization reagent for sucralose. Compared to the latter and to β-naphthol, derivatization with aniline diphenylamine o-phosphoric acid reagent was slightly preferred and densitometry was performed by absorbance measurement at 400 nm. The limit of quantification (LOQ) of sucralose in drinking and surface water was calculated to be 100 ng/L for a given recovery rate of 80% and the extraction of a 0.5 L water sample. The sucralose content determined in four water samples obtained during an interlaboratory trial in 2008 was in good agreement to the mean laboratory values of that trial. According to the t-test, which compares the results with the target value, the means obtained by HPTLC were not significantly different from the respective means of six laboratories, analyzed by HPLC-MS/MS or HPLC-TOF-MS with the use of mostly isotopically labeled standards. The good accuracy and high sample throughput capacity proved HPTLC as a well suited method regarding quantification of sucralose in various aqueous matrices. Copyright © 2010 Elsevier B.V. All rights reserved.

Overexpression of the Coq8 Kinase in Saccharomyces cerevisiae coq Null Mutants Allows for Accumulation of Diagnostic Intermediates of the Coenzyme Q6 Biosynthetic Pathway*

PubMed Central

Xie, Letian X.; Ozeir, Mohammad; Tang, Jeniffer Y.; Chen, Jia Y.; Jaquinod, Sylvie-Kieffer; Fontecave, Marc; Clarke, Catherine F.; Pierrel, Fabien

2012-01-01

Most of the Coq proteins involved in coenzyme Q (ubiquinone or Q) biosynthesis are interdependent within a multiprotein complex in the yeast Saccharomyces cerevisiae. Lack of only one Coq polypeptide, as in Δcoq strains, results in the degradation of several Coq proteins. Consequently, Δcoq strains accumulate the same early intermediate of the Q6 biosynthetic pathway; this intermediate is therefore not informative about the deficient biosynthetic step in a particular Δcoq strain. In this work, we report that the overexpression of the protein Coq8 in Δcoq strains restores steady state levels of the unstable Coq proteins. Coq8 has been proposed to be a kinase, and we provide evidence that the kinase activity is essential for the stabilizing effect of Coq8 in the Δcoq strains. This stabilization results in the accumulation of several novel Q6 biosynthetic intermediates. These Q intermediates identify chemical steps impaired in cells lacking Coq4 and Coq9 polypeptides, for which no function has been established to date. Several of the new intermediates contain a C4-amine and provide information on the deamination reaction that takes place when para-aminobenzoic acid is used as a ring precursor of Q6. Finally, we used synthetic analogues of 4-hydroxybenzoic acid to bypass deficient biosynthetic steps, and we show here that 2,4-dihydroxybenzoic acid is able to restore Q6 biosynthesis and respiratory growth in a Δcoq7 strain overexpressing Coq8. The overexpression of Coq8 and the use of 4-hydroxybenzoic acid analogues represent innovative tools to elucidate the Q biosynthetic pathway. PMID:22593570

Overexpression of the Coq8 kinase in Saccharomyces cerevisiae coq null mutants allows for accumulation of diagnostic intermediates of the coenzyme Q6 biosynthetic pathway.

PubMed

Xie, Letian X; Ozeir, Mohammad; Tang, Jeniffer Y; Chen, Jia Y; Jaquinod, Sylvie-Kieffer; Fontecave, Marc; Clarke, Catherine F; Pierrel, Fabien

2012-07-06

Most of the Coq proteins involved in coenzyme Q (ubiquinone or Q) biosynthesis are interdependent within a multiprotein complex in the yeast Saccharomyces cerevisiae. Lack of only one Coq polypeptide, as in Δcoq strains, results in the degradation of several Coq proteins. Consequently, Δcoq strains accumulate the same early intermediate of the Q(6) biosynthetic pathway; this intermediate is therefore not informative about the deficient biosynthetic step in a particular Δcoq strain. In this work, we report that the overexpression of the protein Coq8 in Δcoq strains restores steady state levels of the unstable Coq proteins. Coq8 has been proposed to be a kinase, and we provide evidence that the kinase activity is essential for the stabilizing effect of Coq8 in the Δcoq strains. This stabilization results in the accumulation of several novel Q(6) biosynthetic intermediates. These Q intermediates identify chemical steps impaired in cells lacking Coq4 and Coq9 polypeptides, for which no function has been established to date. Several of the new intermediates contain a C4-amine and provide information on the deamination reaction that takes place when para-aminobenzoic acid is used as a ring precursor of Q(6). Finally, we used synthetic analogues of 4-hydroxybenzoic acid to bypass deficient biosynthetic steps, and we show here that 2,4-dihydroxybenzoic acid is able to restore Q(6) biosynthesis and respiratory growth in a Δcoq7 strain overexpressing Coq8. The overexpression of Coq8 and the use of 4-hydroxybenzoic acid analogues represent innovative tools to elucidate the Q biosynthetic pathway.

Activity of human kallikrein-related peptidase 6 (KLK6) on substrates containing sequences of basic amino acids. Is it a processing protease?

PubMed

Silva, Roberta N; Oliveira, Lilian C G; Parise, Carolina B; Oliveira, Juliana R; Severino, Beatrice; Corvino, Angela; di Vaio, Paola; Temussi, Piero A; Caliendo, Giuseppe; Santagada, Vincenzo; Juliano, Luiz; Juliano, Maria A

2017-05-01

Human kallikrein 6 (KLK6) is highly expressed in the central nervous system and with elevated level in demyelinating disease. KLK6 has a very restricted specificity for arginine (R) and hydrolyses myelin basic protein, protein activator receptors and human ionotropic glutamate receptor subunits. Here we report a previously unreported activity of KLK6 on peptides containing clusters of basic amino acids, as in synthetic fluorogenic peptidyl-Arg-7-amino-4-carbamoylmethylcoumarin (peptidyl-ACC) peptides and FRET peptides in the format of Abz-peptidyl-Q-EDDnp (where Abz=ortho-aminobenzoic acid and Q-EDDnp=glutaminyl-N-(2,4-dinitrophenyl) ethylenediamine), in which pairs or sequences of basic amino acids (R or K) were introduced. Surprisingly, KLK6 hydrolyzed the fluorogenic peptides Bz-A-R ↓ R-ACC and Z-R ↓ R-MCA between the two R groups, resulting in non-fluorescent products. FRET peptides containing furin processing sequences of human MMP-14, nerve growth factor (NGF), Neurotrophin-3 (NT-3) and Neurotrophin-4 (NT-4) were cleaved by KLK6 at the same position expected by furin. Finally, KLK6 cleaved FRET peptides derived from human proenkephalin after the KR, the more frequent basic residues flanking enkephalins in human proenkephalin sequence. This result suggests the ability of KLK6 to release enkephalin from proenkephalin precursors and resembles furin a canonical processing proteolytic enzyme. Molecular models of peptides were built into the KLK6 structure and the marked preference of the cut between the two R of the examined peptides was related to the extended conformation of the substrates. Copyright © 2017 Elsevier B.V. All rights reserved.

[Discover potential inhibitors of 5-LOX and LTA4H from Rhei Radix et Rhizoma, Notopterygii Rhizoma et Radix and Genitana Macrophyllae Radix based on molecular simulation methods].

PubMed

Gu, Yu; Zhang, Xu; Chen, Yan-Kun; Zhao, Bo-Wen; Zhang, Yan-Ling

2017-12-01

5-lipoxygenase (5-LOX) and leukotriene A4 hydrolase (LTA4H), as the major targets of 5-LOX branch in the arachidonic acid (AA) metabolic pathway, play an important role in the treatment of inflammation. Rhei Radix et Rhizoma, Notopterygii Rhizoma et Radix and Genitana Macrophyllae Radix have clear anti-inflammation activities. In this paper, the targets of 5-LOX and LTA4H were used as the research carrier, and Hiphop module in DS4.0 (Discovery studio) was used to construct ingredients database for preliminary screening of three traditional Chinese medicines based on target inhibitor pharmacophore, so as to obtain 5-LOX and LTA4H potential active ingredients. The ingredients obtained in initial pharmacophore screening were further screened by using CDOCKER module, and the screening rules were established based on the score of initial compound and the key amino acids to obtain 12 potential 5-LOX inhibitors and 7 potential LTA4H inhibitors. To be more specific, the potential 5-LOX inhibitors included 6 ingredients in Rhei Radix et Rhizoma, such as procyanidins B2-3,3'-O-double gallate and revandchinone 2; four ingredients in notopterygium, such as dodecanoic acid and so on. On the other hand, potential LTA4H inhibitors included revandchinone 1, revandchinone 4 in Rhei Radix et Rhizoma, tridecanoic acid, tetracosanoic acid and methyl eicosanoate in Notopterygii Rhizoma et Radix, montanic acid methyl ester and N-docosanoyl-O-aminobenzoate in Genitana Macrophyllae Radix and so on. The molecular simulation methods were highly efficient and time-saving to obtain the potential inhibitors of 5-LOX and LTA4H, which could provide assistance for discovering the chemical quality indicators of anti-inflammatory efficacy of three Chinese herbs, and may be helpful to promote the whole-process quality control of three Chinese herbs. Copyright© by the Chinese Pharmaceutical Association.

Plasmonic enhanced terahertz time-domain spectroscopy system for identification of common explosives

NASA Astrophysics Data System (ADS)

Demiraǧ, Yiǧit; Bütün, Bayram; Özbay, Ekmel

2017-05-01

In this study, we present a classification algorithm for terahertz time-domain spectroscopy systems (THz-TDS) that can be trained to identify most commonly used explosives (C4, HMX, RDX, PETN, TNT, composition-B and blackpowder) and some non-explosive samples (lactose, sucrose, PABA). Our procedure can be used in any THz-TDS system that detects either transmission or reflection spectra at room conditions. After preprocessing the signal in low THz regime (0.1 - 3 THz), our algorithm takes advantages of a latent space transformation based on principle component analysis in order to classify explosives with low false alarm rate.

Systemic functional expression of N-acetyltransferase polymorphism in the F344 Nat2 congenic rat

PubMed Central

Hein, David W.; Bendaly, Jean; Neale, Jason R.; Doll, Mark A.

2008-01-01

Rat lines congenic for the rat N-acetyltransferase 2 [(RAT)Nat2] gene were constructed and characterized. F344 (homozygous Nat2 rapid) males were mated to WKY (homozygous Nat2 slow) females to produce heterozygous F1. F1 females were then backcrossed to F344 males. Heterozygous acetylator female progeny from this and each successive backcross were identified by rat Nat2 genotyping and mated with F344 rapid acetylator males. Following ten generations of backcross mating, heterozygous acetylator brother/sister progeny were mated to produce the homozgygous rapid and slow acetylator Nat2 congenic rat lines. p-Aminobenzoic acid (selective for rat NAT2) and 4-aminobiphenyl N-acetyltransferase activities were expressed in all tissues examined (liver, lung, esophagus, stomach, small intestine, colon, pancreas, kidney, skin, leukocytes, and urinary bladder in male and female rats and in breast of female and prostate of male rats). NAT2 expression in rat extrahepatic tissues was much higher than in liver. In each tissue, activities were Nat2-genotype dependent, with highest levels in homozygous rapid acetylators, intermediate levels in heterozygous acetylators, and lowest in homozygous slow acetylators. Sulfamethazine (selective for rat NAT1) N-acetyltransferase activities were observed in all tissues examined in both male and female rats except for breast (females), bladder and leukocytes. In each tissue, the activity was Nat2-genotype independent, with similar levels in homozygous rapid, heterozygous, and homozygous slow acetylators. These congenic rat lines are useful to investigate the role of NAT2 genetic polymorphism in susceptibility to cancers related to arylamine carcinogen exposures. PMID:18799801

Dendritic azo compounds as a new type amorphous molecular material with quick photoinduced surface-relief-grating formation ability

NASA Astrophysics Data System (ADS)

He, Yaning; Gu, Xinyu; Guo, Miaocai; Wang, Xiaogong

2008-09-01

A series of dendritic azobenzene-containing compounds have been synthesized as a new type amorphous molecular material, which can show quick surface-relief-grating (SRG) formation ability upon light irradiation. For the synthesis, the dendritic precursor tris(2-(ethyl(phenyl)amino)ethyl)benzene-1,3,5-tricarboxylate and tris(3,5-bis(2-(ethyl(phenyl)amino)ethoxy)benzyl)benzene-1,3,5-tricarboxylate were prepared by esterification reactions between 1,3,5-benzenetricarbonyl chloride and N-ethyl- N-hydroxyethyl-aniline and 3,5-bis[2-( N-ethylanilino)ethoxy] benzylalcohol. The precursors were, respectively reacted with the diazonium salts of 4-nitroaniline, 4-aminobenzoic acid, and 4-aminobenzonitrile to introduce different types of donor-acceptor azo chromophores at the peripheral positions. The structure and properties of the dendritic azo compounds were characterized by the spectroscopic methods and thermal analysis. The surface-relief-grating (SRG) formation behavior of the dendritic azo compounds was studied by exposing the spin-coated thin films to an interference pattern of laser beams (532 nm) at modest intensity (100 mW/cm 2). The results show that the azo compounds can form stable amorphous glasses in a broad temperature range. The glass transition temperatures ( Tgs) depend on the backbone structures and the type of the peripheral azo chromophors. The type of the electron withdrawing groups in the p-positions of the terminal azobenzene units shows a significant influence on the SRG inscription rate. For the compounds containing the same type azo chromophores, the SRG inscription rate is also affected by the backbone structure.

Neutral desorption extractive electrospray ionization mass spectrometry for fast screening sunscreen agents in cream cosmetic products.

PubMed

Zhang, Xinglei; Liu, Yan; Zhang, Jinghua; Hu, Zhong; Hu, Bin; Ding, Liying; Jia, Li; Chen, Huanwen

2011-09-15

High throughput analysis of sunscreen agents present in cream cosmetic has been demonstrated, typically 2 samples per minute, using neutral desorption extractive electrospray ionization mass spectrometry (ND-EESI-MS) without sample pretreatment. For the targeted compounds such as 4-Aminobenzoic acid and oxybenzone, ND-EESI-MS method provided linear signal responses in the range of 1-100 ppb. Limits of detection (LOD) of the method were estimated at sub-ppb levels for the analytes tested. Reasonable relative standard deviation (RSD=8.4-16.0%) was obtained as a result of 10 independent measurements for commercial cosmetics samples spiked with each individual sunscreen agents at 1-10 ppb. Acceptable recoveries were achieved in the range of 87-116% for direct analysis of commercial cream cosmetic samples. The experimental data demonstrate that ND-EESI-MS is a useful tool for high throughput screening of sunscreen agents in highly viscous cream cosmetic products, with the capability to obtain quantitative information of the analytes. Copyright © 2011 Elsevier B.V. All rights reserved.

Anaesthetic Tricaine Acts Preferentially on Neural Voltage-Gated Sodium Channels and Fails to Block Directly Evoked Muscle Contraction

PubMed Central

Attili, Seetharamaiah; Hughes, Simon M.

2014-01-01

Movements in animals arise through concerted action of neurons and skeletal muscle. General anaesthetics prevent movement and cause loss of consciousness by blocking neural function. Anaesthetics of the amino amide-class are thought to act by blockade of voltage-gated sodium channels. In fish, the commonly used anaesthetic tricaine methanesulphonate, also known as 3-aminobenzoic acid ethyl ester, metacaine or MS-222, causes loss of consciousness. However, its role in blocking action potentials in distinct excitable cells is unclear, raising the possibility that tricaine could act as a neuromuscular blocking agent directly causing paralysis. Here we use evoked electrical stimulation to show that tricaine efficiently blocks neural action potentials, but does not prevent directly evoked muscle contraction. Nifedipine-sensitive L-type Cav channels affecting movement are also primarily neural, suggesting that muscle Nav channels are relatively insensitive to tricaine. These findings show that tricaine used at standard concentrations in zebrafish larvae does not paralyse muscle, thereby diminishing concern that a direct action on muscle could mask a lack of general anaesthesia. PMID:25090007

Synthesis and Spectral Characterization of Antifungal Sensitive Schiff Base Transition Metal Complexes

PubMed Central

Sakthivel, A.; Rajasekaran, K.

2007-01-01

New N2O2 donor type Schiff base has been designed and synthesized by condensing acetoacetanilido-4-aminoantipyrine with 2-aminobenzoic acid in ethanol. Solid metal complexes of the Schiff base with Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) metal ions were synthesized and characterized by elemental analyses, magnetic susceptibility, molar conduction, fast atom bombardment (FAB) mass, IR, UV-Vis, and 1H NMR spectral studies. The data show that the complexes have the composition of ML type. The UV-Vis. and magnetic susceptibility data of the complexes suggest a square-planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The in vitro antifungal activities of the compounds were tested against fungi such as Aspergillus niger, Aspergillus flavus, Rhizopus stolonifer, Candida albicans, Rhizoctonia bataicola and Trichoderma harizanum. All the metal complexes showed stronger antifungal activities than the free ligand. The minimum inhibitory concentrations (MIC) of the metal complexes were found in the range of 10~31 µg/ml. PMID:24015086

Tyrocidine A Analogues Bearing the Planar d-Phe-2-Abz Turn Motif: How Conformation Impacts Bioactivity.

PubMed

Cameron, Alan J; Edwards, Patrick J B; Harjes, Elena; Sarojini, Vijayalekshmi

2017-12-14

The d-Phe-Pro β-turn of the cyclic β-hairpin antimicrobial decapeptide tyrocidine A, (Tyrc A) was substituted with the d-Phe-2-aminobenzoic acid (2-Abz) motif in a synthetic analogue (1). The NMR structure of 1 demonstrated that compound 1 retained the β-hairpin structure of Tyrc A with additional planarity, resulting in approximately 30-fold reduced hemolysis than Tyrc A. Although antibacterial activity was partially compromised, a single Gln to Lys substitution (2) restored activity equivalent to Tyrc A against S. aureus, enhanced activity against two Gram negative strains and maintained the reduced hemeloysis of 1. Analysis by transmission electron microscopy (TEM) suggested a membrane lytic mechanism of action for these peptides. Compound 2 also exhibits nanomolar antifungal activity in synergy with amphotericin B. The d-Phe-2-Abz turn may serve as a tool for the synthesis of structurally predictable β-hairpin libraries. Unlike traditional β-turn motifs such as d-Pro-Gly, both the 2-Abz and d-Phe rings may be further functionalized.

Crystal and NMR Structures of a Peptidomimetic β-Turn That Provides Facile Synthesis of 13-Membered Cyclic Tetrapeptides.

PubMed

Cameron, Alan J; Squire, Christopher J; Edwards, Patrick J B; Harjes, Elena; Sarojini, Vijayalekshmi

2017-12-14

Herein we report the unique conformations adopted by linear and cyclic tetrapeptides (CTPs) containing 2-aminobenzoic acid (2-Abz) in solution and as single crystals. The crystal structure of the linear tetrapeptide H 2 N-d-Leu-d-Phe-2-Abz-d-Ala-COOH (1) reveals a novel planar peptidomimetic β-turn stabilized by three hydrogen bonds and is in agreement with its NMR structure in solution. While CTPs are often synthetically inaccessible or cyclize in poor yield, both 1 and its N-Me-d-Phe analogue (2) adopt pseudo-cyclic frameworks enabling near quantitative conversion to the corresponding CTPs 3 and 4. The crystal structure of the N-methylated peptide (4) is the first reported for a CTP containing 2-Abz and reveals a distinctly planar 13-membered ring, which is also evident in solution. The N-methylation of d-Phe results in a peptide bond inversion compared to the conformation of 3 in solution. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hexose rearrangements upon fragmentation of N-glycopeptides and reductively aminated N-glycans.

PubMed

Wuhrer, Manfred; Koeleman, Carolien A M; Deelder, André M

2009-06-01

Tandem mass spectrometry of glycans and glycoconjugates in protonated form is known to result in rearrangement reactions leading to internal residue loss. Here we studied the occurrence of hexose rearrangements in tandem mass spectrometry of N-glycopeptides and reductively aminated N-glycans by MALDI-TOF/TOF-MS/MS and ESI-ion trap-MS/MS. Fragmentation of proton adducts of oligomannosidic N-glycans of ribonuclease B that were labeled with 2-aminobenzamide and 2-aminobenzoic acid resulted in transfer of one to five hexose residues to the fluorescently tagged innermost N-acetylglucosamine. Glycopeptides from various biological sources with oligomannosidic glycans were likewise shown to undergo hexose rearrangement reactions, resulting in chitobiose cleavage products that have acquired one or two hexose moieties. Tryptic immunoglobulin G Fc-glycopeptides with biantennary N-glycans likewise showed hexose rearrangements resulting in hexose transfer to the peptide moiety retaining the innermost N-acetylglucosamine. Thus, as a general phenomenon, tandem mass spectrometry of reductively aminated glycans as well as glycopeptides may result in hexose rearrangements. This characteristic of glycopeptide MS/MS has to be considered when developing tools for de novo glycopeptide structural analysis.

Biofuel cells based on direct enzyme-electrode contacts using PQQ-dependent glucose dehydrogenase/bilirubin oxidase and modified carbon nanotube materials.

PubMed

Scherbahn, V; Putze, M T; Dietzel, B; Heinlein, T; Schneider, J J; Lisdat, F

2014-11-15

Two types of carbon nanotube electrodes (1) buckypaper (BP) and (2) vertically aligned carbon nanotubes (vaCNT) have been used for elaboration of glucose/O2 enzymatic fuel cells exploiting direct electron transfer. For the anode pyrroloquinoline quinone dependent glucose dehydrogenase ((PQQ)GDH) has been immobilized on [poly(3-aminobenzoic acid-co-2-methoxyaniline-5-sulfonic acid), PABMSA]-modified electrodes. For the cathode bilirubin oxidase (BOD) has been immobilized on PQQ-modified electrodes. PABMSA and PQQ act as promoter for enzyme bioelectrocatalysis. The voltammetric characterization of each electrode shows current densities in the range of 0.7-1.3 mA/cm(2). The BP-based fuel cell exhibits maximal power density of about 107 µW/cm(2) (at 490 mV). The vaCNT-based fuel cell achieves a maximal power density of 122 µW/cm(2) (at 540 mV). Even after three days and several runs of load a power density over 110 µW/cm(2) is retained with the second system (10mM glucose). Due to a better power exhibition and an enhanced stability of the vaCNT-based fuel cells they have been studied in human serum samples and a maximal power density of 41 µW/cm(2) (390 mV) can be achieved. Copyright © 2014 Elsevier B.V. All rights reserved.

A validated bioanalytical HPLC method for pharmacokinetic evaluation of 2-deoxyglucose in human plasma

PubMed Central

Gounder, Murugesan K.; Lin, Hongxia; Stein, Mark; Goodin, Susan; Bertino, Joseph R.; Kong, Ah-Ng Tony; DiPaola, Robert S.

2015-01-01

2-deoxyglucose (2-DG), an analog of glucose, is widely used to interfere with the glycolysis in tumor cells and studied as a therapeutic approach in clinical trials. To evaluate the pharmacokinetics of 2-DG, we describe the development and validation of a sensitive HPLC fluorescent method for the quantitation of 2-DG in plasma. Plasma samples were deproteinized with methanol and the supernatant was dried at 45°C. The residues were dissolved in methanolic sodium acetate/boric acid solution. 2-DG and other monosaccharides were derivatized to 2-aminobenzoic acid derivatives in a single step in the presence of sodium cyanoborohydride at 80°C for 45min. The analytes were separated on a YMC ODS C18 reversed-phase column using gradient elution. The excitation and emission wavelengths were set at 360 and 425nm. The 2-DG calibration curves were linear over the range of 0.63 to 300μg/mL with the limit of detection of 0.5μg/mL. The assay provided satisfactory intra-day and inter-day precision with RSD less than 9.8% and the accuracy ranged from 86.8% to 110.0%. The HPLC method is reproducible and suitable for the quantitation of 2-DG in plasma. The method was successfully applied to characterize the pharmacokinetics profile of 2-DG in patients with advanced solid tumors. PMID:21932382

Gas-generated thermal oxidation of a coordination cluster for an anion-doped mesoporous metal oxide.

PubMed

Hirai, Kenji; Isobe, Shigehito; Sada, Kazuki

2015-12-18

Central in material design of metal oxides is the increase of surface area and control of intrinsic electronic and optical properties, because of potential applications for energy storage, photocatalysis and photovoltaics. Here, we disclose a facile method, inspired by geochemical process, which gives rise to mesoporous anion-doped metal oxides. As a model system, we demonstrate that simple calcination of a multinuclear coordination cluster results in synchronic chemical reactions: thermal oxidation of Ti8O10(4-aminobenzoate)12 and generation of gases including amino-group fragments. The gas generation during the thermal oxidation of Ti8O10(4-aminobenzoate)12 creates mesoporosity in TiO2. Concurrently, nitrogen atoms contained in the gases are doped into TiO2, thus leading to the formation of mesoporous N-doped TiO2. The mesoporous N-doped TiO2 can be easily synthesized by calcination of the multinuclear coordination cluster, but shows better photocatalytic activity than the one prepared by a conventional sol-gel method. Owing to an intrinsic designability of coordination compounds, this facile synthetic will be applicable to a wide range of metal oxides and anion dopants.

Chlorhexidine digluconate induces mitotic recombination in diploid cells of Aspergillus nidulans.

PubMed

Souza-Júnior, S A; Castro-Prado, M A A

2005-05-01

Chlorhexidine digluconate (1,1'-hexamethylene-bis[(5-p-clorophenyl)-biguanide]) is a bisbiguanidine antiseptic, used to decrease plaque formation and to control periodontal diseases. The determination of the frequency of mitotic crossing-over constitutes a very important method for detecting carcinogenic agents. The recombinogenic potential of chlorhexidine digluconate was evaluated on Aspergillus nidulans by the production of cells homozygous for the following nutritional markers: riboA1, pabaA124, biA1, methA17 and pyroA4. A. nidulans was exposed to three concentrations of chlorhexidine digluconate (1, 5, and 10 microM). Inhibition of colony development, conidiophore morphological alteration (cytotoxic effect), and the recombinogenic effect, indicated by homozygotization index (HI) values higher than 2.0, were observed for all concentrations of chlorhexidine digluconate. A homozygous pyro+//pyro+ diploid strain and a diploid homozygous for the recessive w gene were isolated from UT448//A757 diploid treated with chlorhexidine digluconate, emphasazing its recombinogenic potential. Although, beneficial effects of chlorhexidine, as an antiseptic agent, are reported in the literature, our results revealed that chlorhexidine digluconate, at less levels lowered those used clinically, caused toxic and recombinogenic effects on diploid A. nidulans strain.

Porcine dentin sialoprotein glycosylation and glycosaminoglycan attachments

PubMed Central

2011-01-01

Background Dentin sialophosphoprotein (Dspp) is a multidomain, secreted protein that is critical for the formation of tooth dentin. Mutations in DSPP cause inherited dentin defects categorized as dentin dysplasia type II and dentinogenesis imperfecta type II and type III. Dentin sialoprotein (Dsp), the N-terminal domain of dentin sialophosphoprotein (Dspp), is a highly glycosylated proteoglycan, but little is known about the number, character, and attachment sites of its carbohydrate moieties. Results To identify its carbohydrate attachment sites we isolated Dsp from developing porcine molars and digested it with endoproteinase Glu-C or pronase, fractionated the digestion products, identified fractions containing glycosylated peptides using a phenol sulfuric acid assay, and characterized the glycopeptides by N-terminal sequencing, amino acid analyses, or LC/MSMS. To determine the average number of sialic acid attachments per N-glycosylation, we digested Dsp with glycopeptidase A, labeled the released N-glycosylations with 2-aminobenzoic acid, and quantified the moles of released glycosylations by comparison to labeled standards of known concentration. Sialic acid was released by sialidase digestion and quantified by measuring β-NADH reduction of pyruvic acid, which was generated stoichiometrically from sialic acid by aldolase. To determine its forms, sialic acid released by sialidase digestion was labeled with 1,2-diamino-4,5-methyleneoxybenzene (DMB) and compared to a DMB-labeled sialic acid reference panel by RP-HPLC. To determine the composition of Dsp glycosaminoglycan (GAG) attachments, we digested Dsp with chondroitinase ABC and compared the chromotagraphic profiles of the released disaccharides to commercial standards. N-glycosylations were identified at Asn37, Asn77, Asn136, Asn155, Asn161, and Asn176. Dsp averages one sialic acid per N-glycosylation, which is always in the form of N-acetylneuraminic acid. O-glycosylations were tentatively assigned at Thr200, Thr216 and Thr316. Porcine Dsp GAG attachments were found at Ser238 and Ser250 and were comprised of chondroitin 6-sulfate and chondroitin 4-sulfate in a ratio of 7 to 3, respectively. Conclusions The distribution of porcine Dsp posttranslational modifications indicate that porcine Dsp has an N-terminal domain with at least six N-glycosylations and a C-terminal domain with two GAG attachments and at least two O-glycosylations. PMID:21291557

Structure-function study on a de novo synthetic hydrophobic ion channel.

PubMed Central

Qi, Z; Sokabe, M; Donowaki, K; Ishida, H

1999-01-01

Ion conduction properties of a de novo synthesized channel, formed from cyclic octa-peptides consisting of four alternate L-alanine (Ala) and N'-acylated 3-aminobenzoic acid (Aba) moieties, were studied in bilayer membranes. The single-channel conductance was 9 pS in symmetrical 500 mM KCl. The channel favored permeation of cations over anions with a permeability ratio (PCl-/PK+) of 0.15. The selectivity sequence among monovalent cations based on permeability ratio (PX+/PK+) fell into an order: NH4+(1.4) > Cs+(1. 1) >/= K+(1.0) > Na+(0.4) >> Li+(0). The conductance-activity relationship of the channel in K+ solutions followed simple Michaelis-Menten kinetics with a half-maximal saturating activity of 8 mM and a maximal conductance of 9 pS. The permeability ratio PNa+/PK+ remained constant ( approximately 0.40) under biionic concentrations from 10 to 500 mM. These results suggests that the channel is a one-ion channel. The pore diameter probed by a set of organic cations was approximately 6 A. The single-channel current was blocked by Ca2+ in a dose-dependent manner that followed a single-site titration curve with a voltage-dependent dissociation constant of 0.6 mM at 100 mV. The electric distance of the binding site for Ca2+ was 0.07 from both entrances of the channel, indicating the presence of two symmetrical binding sites in each vicinity of the channel entrance. Correlations between conduction properties and structural aspects of the channel are discussed in terms of a three-barrier and two-binding-site (3B2S) model of Eyring rate theory. All available structural information supported an idea that the channel was formed from a tail-to-tail associated dimer of the molecule, the pore of which was lined with hydrophobic acyl chains. This is the first report to have made a systematic analysis of ion permeation through a hydrophobic pore. PMID:9929469

Characterization of the M32 metallocarboxypeptidase of Trypanosoma brucei: differences and similarities with its orthologue in Trypanosoma cruzi

PubMed Central

Frasch, Alejandra P.; Carmona, Adriana K.; Juliano, Luiz; Cazzulo, Juan J.; Niemirowicz, Gabriela T.

2012-01-01

Metallocarboxypeptidases (MCP) of the M32 family of peptidases have been identified in a number of prokaryotic organisms but they are absent from eukaryotic genomes with the remarkable exception of those of trypanosomatids. The genome of Trypanosoma brucei, the causative agent of Sleeping Sickness, encodes one such MCP which displays 72% identity to the characterized TcMCP-1 from Trypanosoma cruzi. As its orthologue, TcMCP-1, Trypanosoma brucei MCP is a cytosolic enzyme expressed in both major stages of the parasite. Purified recombinant TbMCP-1 exhibits a significant hydrolytic activity against the carboxypeptidase B substrate FA (furylacryloil)-Ala-Lys at pH 7.0–7.8 resembling the T. cruzi enzyme. S everal divalent cations had little effect on TbMCP-1 activity but increasing amounts of Co2+ inhibited the enzyme. Despite having similar tertiary structure, both protozoan MCPs display different substrate specificity with respect to P1 position. Thus, TcMCP-1 enzyme cleaved Abz-FVK-(Dnp)-OH substrate (where Abz: o-aminobenzoic acid and Dnp: 2,4-dinitrophenyl) whereas TbMCP-1 had no activity on this substrate. Comparative homology models and sequence alignments using TcMCP-1 as a template led us to map several residues that could explain this difference. To verify this hypothesis, site-directed mutagenesis was undertaken replacing the TbMCP-1 residues by those present in TcMCP-1. We found that the substitution A414M led TbMCP-1 to gain activity on Abz-FVK-(Dnp)-OH, thus showing that this residue is involved in specificity determination, probably being part of the S1 sub-site. Moreover, the activity of both protozoan MCPs was explored on two vasoactive compounds such as bradykinin and angiotensin I resulting in two different hydrolysis patterns. PMID:22575602

Validated RP-HPLC/DAD Method for the Quantification of Insect Repellent Ethyl 2-Aminobenzoate in Membrane-Moderated Matrix Type Monolithic Polymeric Device.

PubMed

Islam, Johirul; Zaman, Kamaruz; Chakrabarti, Srijita; Sharma Bora, Nilutpal; Mandal, Santa; Pratim Pathak, Manash; Srinivas Raju, Pakalapati; Chattopadhyay, Pronobesh

2017-07-01

A simple, accurate and sensitive reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for the estimation of ethyl 2-aminobenzoate (EAB) in a matrix type monolithic polymeric device and validated as per the International Conference on Harmonization guidelines. The analysis was performed isocratically on a ZORBAX Eclipse plus C18 analytical column (250 × 4.4 mm, 5 μm) and a diode array detector (DAD) using acetonitrile and water (75:25 v/v) as the mobile phase by keeping the flow-rate constant at 1.0 mL/min. Determination of EAB was not interfered in the presence of excipients. Inter- and intra-day relative standard deviations were not higher than 2%. Mean recovery was between 98.7 and 101.3%. Calibration curve was linear in the concentration range of 0.5-10 µg/mL. Limits of detection and quantification were 0.19 and 0.60 µg/mL, respectively. Thus, the present report put forward a novel method for the estimation of EAB, an emerging insect repellent, by using RP-HPLC technique. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Xenobiotic metabolizing enzyme activities in cells used for testing skin sensitization in vitro.

PubMed

Fabian, E; Vogel, D; Blatz, V; Ramirez, T; Kolle, S; Eltze, T; van Ravenzwaay, B; Oesch, F; Landsiedel, R

2013-09-01

For ethical and regulatory reasons, in vitro tests for scoring potential toxicities of cosmetics are essential. A test strategy for investigating potential skin sensitization using two human keratinocytic and two human dendritic cell lines has been developed (Mehling et al. Arch Toxicol 86:1273–1295, 2012). Since prohaptens may be metabolically activated in the skin, information on xenobiotic metabolizing enzyme (XME) activities in these cell lines is of high interest. In this study, XME activity assays, monitoring metabolite or cofactor, showed the following: all three passages of keratinocytic (KeratinoSens® and LuSens) and dendritic (U937 und THP-1) cells displayed N-acetyltransferase 1 (NAT1) activities (about 6–60 nmol/min/mg S9-protein for acetylation of para-aminobenzoic acid). This is relevant since reactive species of many cosmetics are metabolically controlled by cutaneous NAT1. Esterase activities of about 1–4 nmol fluorescein diacetate/min/mg S9-protein were observed in all passages of investigated keratinocytic and about 1 nmol fluorescein diacetate/min/mg S9-protein in dendritic cell lines. This is also of practical relevance since many esters and amides are detoxified and others activated by cutaneous esterases. In both keratinocytic cell lines, activities of aldehyde dehydrogenase (ALDH) were observed (5–17 nmol product/min/mg cytosolic protein). ALDH is relevant for the detoxication of reactive aldehydes. Activities of several other XME were below detection, namely the investigated cytochrome P450-dependent alkylresorufin O-dealkylases 7-ethylresorufin O-deethylase, 7-benzylresorufin O-debenzylase and 7-pentylresorufin O-depentylase (while NADPH cytochrome c reductase activities were much above the limit of quantification), the flavin-containing monooxygenase, the alcohol dehydrogenase as well as the UDP glucuronosyl transferase activities.

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

Hurtubise, R.J.

Interaction models were developed for moisture effects on room-temperature fluorescence (RTF) and room-temperature phosphorescence (RTP) of compounds adsorbed on filter paper. The models described both dynamic and matrix quenching and also related the Young modulus of filter paper to quenching of phosphor on moist filter paper. Photophysical parameters for lumiphors in solution and on solid matrices were compared. Results showed that for some compounds, solid-matrix luminescence has greater analytical potential than solution luminescence. Also, the solid-matrix systems into one of two categories depending on how the intersystem crossing rate constants change with temperature. The first study was carried out onmore » effects of heavy atom on solid-matrix luminescence. With some heavy atoms, maximum solid-matrix phosphorescence quantum yield was obtained at room temperature, and there was no need to use low temperature to obtain a strong phosphorescence signal. By studying solid-matrix luminescence properties of phosphors adsorbed on sodium acetate and deuterated sodium acetate, an interaction model was developed for p-aminobenzoic acid anion adsorbed on sodium acetate. It was shown that the energy-gap law was applicable to solid-matrix luminescence. Also, deuterated phenanthrene and undeuterated phenanthrene were used to study nonradiative transition of excited triplet state of adsorbed phosphors. Heat capacities of several solid matrices were obtained vs temperature and related to vibrational coupling of solid matrix with phosphor. Photophysical study was performed on the hydrolysis products of benzo(a)pyrene-DNA adducts. Also, an analytical method was developed for tetrols in human lung fractions. Work was initiated on the formation of room temperature glasses with glucose and trehalose. Also, work has begun for the development of an oxygen sensor by measuring the RTP quenching of triphenylene on filter paper.« less

A photoaffinity ligand for dopamine D2 receptors: azidoclebopride.

PubMed

Niznik, H B; Guan, J H; Neumeyer, J L; Seeman, P

1985-02-01

In order to label D2 dopamine receptors selectively and covalently by means of a photosensitive compound, azidoclebopride was synthesized directly from clebopride. The dissociation constant (KD) of clebopride for the D2 dopamine receptor (canine brain striatum) was 1.5 nM, while that for azidoclebopride was 21 nM. The affinities of both clebopride and azidoclebopride were markedly reduced in the absence of sodium chloride. In the presence of ultraviolet light, azidoclebopride inactivated D2 dopamine receptors irreversibly, as indicated by the inability of the receptors to bind [3H]spiperone. Maximal photoinactivation of about 60% of the D2 dopamine receptors occurred at 1 microM azidoclebopride; 30% of the receptors were inactivated at 80 nM azidoclebopride (pseudo-IC50). Dopamine agonists selectively protected the D2 receptors from being inactivated by azidoclebopride, the order of potency being (-)-N-n-propylnorapomorphine greater than apomorphine greater than (+/-)-6,7-dihydroxy-2-aminotetralin greater than (+)-N-n-propylnorapomorphine greater than dopamine greater than noradrenaline greater than serotonin. Similarly, dopaminergic antagonists prevented the photoinactivation of D2 receptors by azidoclebopride with the following order of potency: spiperone greater than (+)-butaclamol greater than haloperidol greater than clebopride greater than (-)-sulpiride greater than (-)-butaclamol. The degree of D2 dopamine receptor photoinduced inactivation by azidoclebopride was not significantly affected by scavengers such as p-aminobenzoic acid and dithiothreitol. Furthermore, irradiation of striatal membranes with a concentration of azidoclebopride sufficient to inactivate dopamine D2 receptors by 60% did not significantly reduce dopamine D1, serotonin (S2), benzodiazepine, alpha 1- or beta-noradrenergic receptors. This study describes the use of a novel and selective photoaffinity ligand for brain dopamine D2 receptors. The molecule, in radiolabeled form, may aid in the molecular characterization of these receptors.

Occurrence, fate and ecotoxicological risk of personal care products in urban river-groundwater interface

NASA Astrophysics Data System (ADS)

Jurado, Anna; Pau Serra, Maria; Díaz-Cruz, M. Silvia; Vázquez-Suñé, Enric; Pujades, Estanislao; Barceló, Damià

2016-04-01

This work presents the occurrence and fate of selected personal care products (PCPs) in the urban river-groundwater interface. To this end, urban groundwater and river samples were collected in Sant Adrià del Besòs (NE of Spain) and a total of 16 PCPs were analyzed including benzophenone derivatives, camphor derivatives, p-aminobenzoic acid derivatives, triazoles and parabens in three different campaigns (from May 2010 to July 2014). These compounds reach the aquifer through the recharge of River Besòs that receives large amounts of effluents from waste water treatment plants. Results shown that most of compounds were not or barely detected (maximum concentrations around 30 ng/L) in groundwater samples during the different sampling campaigns. Only two triazoles, named as benzotriazole (BZT) and methyl benzotriazol (MeBZT) were found at high concentrations in groundwater samples (maximum concentration around 2000 ng/L). The fate of PCPs in the aquifer was assessed using mixing analysis considering the temporal variability of the River Besòs. Overall, measured groundwater concentrations were significantly much lower than those estimated by the mixing of the river water. This observation suggested that most of the PCPs are naturally removed when river water infiltrates the aquifer. However, some compounds were more persistent in the aquifer. These compounds were in descending order: the triazoles MeBZT and BZT followed by the camphor derivative 4MBC. The measured concentrations allowed us to assess the environmental risk posed by the selected UV-Fs (e.g. benzophenone derivatives) in the river-groundwater samples. Hazard Quotients (HQs) for diferent aquatic species were calculated in order to characterise the ecotoxicity potential of the studied compounds in the river-groundwater interface. HQ values will be presented and discussed in the presentation.

A validated bioanalytical HPLC method for pharmacokinetic evaluation of 2-deoxyglucose in human plasma.

PubMed

Gounder, Murugesan K; Lin, Hongxia; Stein, Mark; Goodin, Susan; Bertino, Joseph R; Kong, Ah-Ng Tony; DiPaola, Robert S

2012-05-01

2-Deoxyglucose (2-DG), an analog of glucose, is widely used to interfere with glycolysis in tumor cells and studied as a therapeutic approach in clinical trials. To evaluate the pharmacokinetics of 2-DG, we describe the development and validation of a sensitive HPLC fluorescent method for the quantitation of 2-DG in plasma. Plasma samples were deproteinized with methanol and the supernatant was dried at 45°C. The residues were dissolved in methanolic sodium acetate-boric acid solution. 2-DG and other monosaccharides were derivatized to 2-aminobenzoic acid derivatives in a single step in the presence of sodium cyanoborohydride at 80°C for 45 min. The analytes were separated on a YMC ODS C₁₈ reversed-phase column using gradient elution. The excitation and emission wavelengths were set at 360 and 425 nm. The 2-DG calibration curves were linear over the range of 0.63-300 µg/mL with a limit of detection of 0.5 µg/mL. The assay provided satisfactory intra-day and inter-day precision with RSD less than 9.8%, and the accuracy ranged from 86.8 to 110.0%. The HPLC method is reproducible and suitable for the quantitation of 2-DG in plasma. The method was successfully applied to characterize the pharmacokinetics profile of 2-DG in patients with advanced solid tumors. Copyright © 2011 John Wiley & Sons, Ltd.

Secondary Interactions Arrest the Hemiaminal Intermediate To Invert the Modus Operandi of Schiff Base Reaction: A Route to Benzoxazinones.

PubMed

Patel, Ketan; Deshmukh, Satej S; Bodkhe, Dnyaneshwar; Mane, Manoj; Vanka, Kumar; Shinde, Dinesh; Rajamohanan, Pattuparambil R; Nandi, Shyamapada; Vaidhyanathan, Ramanathan; Chikkali, Samir H

2017-04-21

Discovered by Hugo Schiff, condensation between amine and aldehyde represents one of the most ubiquitous reactions in chemistry. This classical reaction is widely used to manufacture pharmaceuticals and fine chemicals. However, the rapid and reversible formation of Schiff base prohibits formation of alternative products, of which benzoxazinones are an important class. Therefore, manipulating the reactivity of two partners to invert the course of this reaction is an elusive target. Presented here is a synthetic strategy that regulates the sequence of Schiff base reaction via weak secondary interactions. Guided by the computational models, reaction between 2,3,4,5,6-pentafluoro-benzaldehyde with 2-amino-6-methylbenzoic acid revealed quantitative (99%) formation of 5-methyl-2-(perfluorophenyl)-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (15). Electron donating and electron withdrawing ortho-substituents on 2-aminobenzoic acid resulted in the production of benzoxazinones 9-36. The mode of action was tracked using low temperature NMR, UV-vis spectroscopy, and isotopic ( 18 O) labeling experiments. These spectroscopic mechanistic investigations revealed that the hemiaminal intermediate is arrested by the hydrogen-bonding motif to yield benzoxazinone. Thus, the mechanistic investigations and DFT calculations categorically rule out the possibility of in situ imine formation followed by ring-closing, but support instead hydrogen-bond assisted ring-closing to prodrugs. This unprecedented reaction represents an interesting and competitive alternative to metal catalyzed and classical methods of preparing benzoxazinone.

Cupric ion reducing antioxidant capacity assay for antioxidants in human serum and for hydroxyl radical scavengers.

PubMed

Apak, Reşat; Güçlü, Kubilay; Ozyürek, Mustafa; Bektaşoğlu, Burcu; Bener, Mustafa

2010-01-01

Tests measuring the combined antioxidant effect of the nonenzymatic defenses in biological fluids may be useful in providing an index of the organism's capability to counteract reactive species known as pro-oxidants, resist oxidative damage, and combat oxidative stress-related diseases. The selected chromogenic redox reagent for the assay of human serum should be easily accessible, stable, selective, and respond to all types of biologically important antioxidants such as ascorbic acid, alpha-tocopherol, beta-carotene, reduced glutathione (GSH), uric acid, and bilirubin, regardless of chemical type or hydrophilicity. Our recently developed cupric reducing antioxidant capacity (CUPRAC) spectrophotometric method for a number of polyphenols and flavonoids using the copper(II)-neocuproine reagent in ammonium acetate buffer is now applied to a complete series of plasma antioxidants for the assay of total antioxidant capacity of serum, and the resulting absorbance at 450 nm is recorded either directly (e.g., for ascorbic acid, alpha-tocopherol, and glutathione) or after incubation at 50 degrees C for 20 min (e.g., for uric acid, bilirubin, and albumin), quantitation being made by means of a calibration curve. The lipophilic antioxidants, alpha-tocopherol and beta-carotene, are assayed in dichloromethane. Lipophilic antioxidants of serum are extracted with n-hexane from an ethanolic solution of serum subjected to centrifugation. Hydrophilic antioxidants of serum are assayed in the centrifugate after perchloric acid precipitation of proteins. The CUPRAC molar absorptivities, linear ranges, and TEAC (trolox equivalent antioxidant capacity) coefficients of the serum antioxidants are established, and the results are evaluated in comparison with the findings of the ABTS/TEAC reference method. The intra- and inter-assay coefficients of variation (CVs) are 0.7 and 1.5%, respectively, for serum. The CUPRAC assay proved to be efficient for glutathione and thiol-type antioxidants, for which the FRAP (ferric reducing antioxidant potency) test is basically nonresponsive. The additivity of absorbances of all the tested antioxidants confirmed that antioxidants in the CUPRAC test do not chemically interact among each other so as to cause an intensification or quenching of the theoretically expected absorbance, and that a total antioxidant capacity (TAC) assay of serum is possible. As a distinct advantage over other electron-transfer based assays (e.g., Folin, FRAP, ABTS, DPPH), CUPRAC is superior in regard to its realistic pH close to the physiological pH, favorable redox potential, accessibility and stability of reagents, and applicability to lipophilic antioxidants as well as hydrophilic ones. The CUPRAC procedure can also assay hydroxyl radicals, being the most reactive oxygen species (ROS). As a more convenient, efficient, and less costly alternative to HPLC/electrochemical detection techniques and to the nonspecific, low-yield TBARS test, we use p-aminobenzoate, 2,4- and 3,5-dimethoxybenzoate probes for detecting hydroxyl radicals generated from an equivalent mixture of [Fe(II)+EDTA] with hydrogen peroxide. The produced hydroxyl radicals attack both the probe and the water-soluble antioxidants in 37 degrees C-incubated solutions for 2 h. The CUPRAC absorbance of the ethylacetate extract due to the reduction of Cu(II)-neocuproine reagent by the hydroxylated probe decreases in the presence of (.)OH scavengers, the difference being proportional to the scavenging ability of the tested compound. The developed method is less lengthy, more specific, and of a higher yield than the classical TBARS assay.

Protomers of benzocaine: solvent and permittivity dependence.

PubMed

Warnke, Stephan; Seo, Jongcheol; Boschmans, Jasper; Sobott, Frank; Scrivens, James H; Bleiholder, Christian; Bowers, Michael T; Gewinner, Sandy; Schöllkopf, Wieland; Pagel, Kevin; von Helden, Gert

2015-04-01

The immediate environment of a molecule can have a profound influence on its properties. Benzocaine, the ethyl ester of para-aminobenzoic acid that finds an application as a local anesthetic, is found to adopt in its protonated form at least two populations of distinct structures in the gas phase, and their relative intensities strongly depend on the properties of the solvent used in the electrospray ionization process. Here, we combine IR-vibrational spectroscopy with ion mobility-mass spectrometry to yield gas-phase IR spectra of simultaneously m/z and drift-time-resolved species of benzocaine. The results allow for an unambiguous identification of two protomeric species: the N- and O-protonated forms. Density functional theory calculations link these structures to the most stable solution and gas-phase structures, respectively, with the electric properties of the surrounding medium being the main determinant for the preferred protonation site. The fact that the N-protonated form of benzocaine can be found in the gas phase is owed to kinetic trapping of the solution-phase structure during transfer into the experimental setup. These observations confirm earlier studies on similar molecules where N- and O-protonation have been suggested.

A possible alternative mechanism of kinin generation in vivo by cathepsin L.

PubMed

Puzer, Luciano; Vercesi, Juliana; Alves, Marcio F M; Barros, Nilana M T; Araujo, Mariana S; Aparecida Juliano, Maria; Reis, Marina L; Juliano, Luiz; Carmona, Adriana K

2005-07-01

We investigated the ability of cathepsin L to induce a hypotensive effect after intravenous injection in rats and correlated this decrease in blood pressure with kinin generation. Simultaneously with blood pressure decrease, we detected plasma kininogen depletion in the treated rats. The effect observed in vivo was abolished by pre-incubation of cathepsin L with the cysteine peptidase-specific inhibitor E-64 (1 microM) or by previous administration of the bradykinin B2 receptor antagonist JE049 (4 mg/kg). A potentiation of the hypotensive effect caused by cathepsin L was observed by previous administration of the angiotensin I-converting enzyme inhibitor captopril (5 mg/kg). In vitro studies indicated that cathepsin L excised bradykinin from the synthetic fluorogenic peptide Abz-MTSVIRRPPGFSPFRAPRV-NH2, based on the Met375-Val393 sequence of rat kininogen (Abz = o-aminobenzoic acid). In conclusion, our data indicate that in vivo cathepsin L releases a kinin-related peptide, and in vitro experiments suggest that the kinin generated is bradykinin. Although it is well known that cysteine proteases are strongly inhibited by kininogen, cathepsin L could represent an alternative pathway for kinin production in pathological processes.

Determination of N-glycans by high performance liquid chromatography using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as the glycosylamine labeling reagent.

PubMed

Wu, Yike; Sha, Qiuyue; Du, Juan; Wang, Chang; Zhang, Liang; Liu, Bi-Feng; Lin, Yawei; Liu, Xin

2018-02-02

Robust, efficient identification and accurate quantification of N-glycans are of great significance in N-glycomics analysis. Here, a simple and rapid derivatization method, based on the combination of microwave-assisted deglycosylation and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) labeling, was developed for the analysis of N-glycan by high performance liquid chromatography with fluorescence detection (HPLC-FLD). After optimizing various parameters affecting deglycosylation and derivatization by RNase B, the time for N-glycan labeling was shortened to 50 min with ∼10-fold enhancement in detection sensitivity comparing to conventional 2-aminobenzoic acid (2-AA) labeling method. Additionally, the method showed good linearity (correlation coefficients > 0.991) and reproducibility (RSD < 8.7%). These advantages of the proposed method were further validated by the analysis of complex samples, including fetuin and human serum. Investigation of serum N-glycome for preliminary diagnosis of human lung cancer was conducted, where significant changes of several N-glycans corresponding to core-fucosylated, mono- and disialylated glycans have been evidenced by a series of statistical analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

Morphological structure of Gluconacetobacter xylinus cellulose and cellulose-based organic-inorganic composite materials

NASA Astrophysics Data System (ADS)

Smyslov, R. Yu; Ezdakova, K. V.; Kopitsa, G. P.; Khripunov, A. K.; Bugrov, A. N.; Tkachenko, A. A.; Angelov, B.; Pipich, V.; Szekely, N. K.; Baranchikov, A. E.; Latysheva, E.; Chetverikov, Yu O.; Haramus, V.

2017-05-01

Scanning electron microscopy, ultra-small-angle neutron scattering (USANS), small-angle neutron and X-ray scattering (SANS and SAXS), as well as low-temperature nitrogen adsorption, were used in the studies of micro- and mesostructure of polymer matrix prepared from air-dry preliminarily disintegrated cellulose nano-gel film (synthesized by Gluconacetobacter xylinus) and the composites based on this bacterial cellulose. The composites included ZrO2 nanoparticles, Tb3+ in the form of low molecular weight salt and of metal-polymer complex with poly(vinylpyrrolydone)-poly(methacryloyl-o-aminobenzoic acid) copolymer. The combined analysis of the data obtained allowed revealing three levels of fractal organization in mesostructure of G. xylinus cellulose and its composites. It was shown that both the composition and an aggregation state of dopants have a significant impact on the structural characteristics of the organic-inorganic composites. The composites containing Tb3+ ions demonstrate efficient luminescence; its intensity is an order of magnitude higher in the case of the composites with the metal-polymer complex. It was found that there is the optimal content of ZrO2 nanoparticles in composites resulting in increased Tb3+ luminescence.

Biodegradation and Transformation of Nitroaromatic Compounds (POSTPRINT)

DTIC Science & Technology

2012-07-01

groups. Reductive deamination of 4 -aminobenzoate metab· elites before ring cleavage ( 64) and degradation of 3-amino· benzoate (65) have been...Bacteri a from a variety of sources can degrade compounds such as 4 -ni- rrophenol that have been widely distributed in the en viron· ment ( 1, 3 7, 72...on the batch culture technique is continuous perfusion and recirculation in small soil columns ( 4 ). Isolation of Degradative Strains When a mixed

New high-performance liquid chromatography assay for glycosyltransferases based on derivatization with anthranilic acid and fluorescence detection.

PubMed

Anumula, Kalyan Rao

2012-07-01

Assays were developed using the unique labeling chemistry of 2-aminobenzoic acid (2AA; anthranilic acid, AA) for measuring activities of both β1-4 galactosyltransferase (GalT-1) and α2-6 sialyltransferase (ST-6) by high-performance liquid chromatography (HPLC) with fluorescence detection (Anumula KR. 2006. Advances in fluorescence derivatization methods for high-performance liquid chromatographic analysis of glycoprotein carbohydrates. Anal Biochem. 350:1-23). N-Acetylglucosamine (GlcNAc) and N-acetyllactosamine were used as acceptors and uridine diphosphate (UDP)-galactose and cytidine monophosphate (CMP)-N-acetylneuraminic acid (NANA) as donors for GalT-1 and ST-6, respectively. Enzymatic products were labeled in situ with AA and were separated from the substrates on TSKgel Amide 80 column using normal-phase conditions. Enzyme units were determined from the peak areas by comparison with the concomitantly derivatized standards Gal-β1-4GlcNAc and NANA-α2-6 Gal-β1-4GlcNAc. Linearity (time and enzyme concentration), precision (intra- and interassay) and reproducibility for the assays were established. The assays were found to be useful in monitoring the enzyme activities during isolation and purification. The assays were highly sensitive and performed equal to or better than the traditional radioactive sugar-based measurements. The assay format can also be used for measuring the activity of other transferases, provided that the carbohydrate acceptors contain a reducing end for labeling. An assay for glycoprotein acceptors was developed using IgG. A short HPLC profiling method was developed for the separation of IgG glycans (biantennary G0, G1, G2, mono- and disialylated), which facilitated the determination of GalT-1 and ST-6 activities in a rapid manner. Furthermore, this profiling method should prove useful for monitoring the changes in IgG glycans in clinical settings.

Responses to clomazone and 5-ketoclomazone by Echinochloa phyllopogon resistant to multiple herbicides in Californian rice fields.

PubMed

Yasuor, Hagai; TenBrook, Patti L; Tjeerdema, Ronald S; Fischer, Albert J

2008-10-01

Late watergrass [Echinochloa phyllopogon (Stapf.) Koss.] is a major weed of Californian rice that has evolved P450-mediated metabolic resistance to multiple herbicides. Resistant (R) populations are also poorly controlled by the recently introduced herbicide clomazone. The authors assessed whether this cross-resistance was also P450 mediated, and whether R plants also had reduced sensitivity to photooxidation. Understanding mechanism(s) of resistance facilitates the design of herbicide management strategies to delay resistance evolution. Ratios (R/S) of R to susceptible (S) GR(50) were near 2.0. [(14)C]Clomazone uptake was similar in R and S plants. Clomazone and its metabolite 5-ketoclomazone reduced chlorophyll and carotenoids in S more than in R plants. The P450 inhibitors disulfoton and 1-aminobenzo-triazole (ABT) safened clomazone in R and S plants. Disulfoton safened 5-ketoclomazone only in S plants, while ABT synergized 5-ketoclomazone mostly against S plants. Paraquat was more toxic in S than in R plants. Cross-resistance to clomazone explains failures to control R plants in rice fields, and safening by P450 inhibitors suggests that oxidative activation of clomazone is needed for toxicity to E. phyllopogon. Clomazone resistance requires mitigation of 5-ketoclomazone toxicity, but P450 detoxification may not significantly confer resistance, as P450 inhibitors poorly synergized 5-ketoclopmazone in R plants. Responses to paraquat suggest research on mechanisms to mitigate photooxidation in R and S plants is needed.

Glucosylated free oligosaccharides are biomarkers of endoplasmic- reticulum alpha-glucosidase inhibition.

PubMed

Alonzi, Dominic S; Neville, David C A; Lachmann, Robin H; Dwek, Raymond A; Butters, Terry D

2008-01-15

The inhibition of ER (endoplasmic reticulum) alpha-glucosidases I and II by imino sugars, including NB-DNJ (N-butyl-deoxynojirimycin), causes the retention of glucose residues on N-linked oligosaccharides. Therefore, normal glycoprotein trafficking and processing through the glycosylation pathway is abrogated and glycoproteins are directed to undergo ERAD (ER-associated degradation), a consequence of which is the production of cytosolic FOS (free oligosaccharides). Following treatment with NB-DNJ, FOS were extracted from cells, murine tissues and human plasma and urine. Improved protocols for analysis were developed using ion-exchange chromatography followed by fluorescent labelling with 2-AA (2-aminobenzoic acid) and purification by lectin-affinity chromatography. Separation of 2-AA-labelled FOS by HPLC provided a rapid and sensitive method that enabled the detection of all FOS species resulting from the degradation of glycoproteins exported from the ER. The generation of oligosaccharides derived from glucosylated protein degradation was rapid, reversible, and time- and inhibitor concentration-dependent in cultured cells and in vivo. Long-term inhibition in cultured cells and in vivo indicated a slow rate of clearance of glucosylated FOS. In mouse and human urine, glucosylated FOS were detected as a result of transrenal excretion and provide unique and quantifiable biomarkers of ER-glucosidase inhibition.

Mediatorless solar energy conversion by covalently bonded thylakoid monolayer on the glassy carbon electrode.

PubMed

Lee, Jinhwan; Im, Jaekyun; Kim, Sunghyun

2016-04-01

Light reactions of photosynthesis that take place in thylakoid membranes found in plants or cyanobacteria are among the most effective ways of utilizing light. Unlike most researches that use photosystem I or photosystem II as conversion units for converting light to electricity, we have developed a simple method in which the thylakoid monolayer was covalently immobilized on the glassy carbon electrode surface. The activity of isolated thylakoid membrane was confirmed by measuring evolving oxygen under illumination. Glassy carbon surfaces were first modified with partial or full monolayers of carboxyphenyl groups by reductive C-C coupling using 4-aminobenzoic acid and aniline and then thylakoid membrane was bioconjugated through the peptide bond between amine residues of thylakoid and carboxyl groups on the surface. Surface properties of modified surfaces were characterized by cyclic voltammetry, contact angle measurements, and electrochemical impedance spectroscopy. Photocurrent of 230 nA cm(-2) was observed when the thylakoid monolayer was formed on the mixed monolayer of 4-carboxylpheny and benzene at applied potential of 0.4V vs. Ag/AgCl. A small photocurrent resulted when the 4-carboxyphenyl full monolayer was used. This work shows the possibility of solar energy conversion by directly employing the whole thylakoid membrane through simple surface modification. Copyright © 2015 Elsevier B.V. All rights reserved.

Review on Abyssomicins: Inhibitors of the Chorismate Pathway and Folate Biosynthesis.

PubMed

Sadaka, Carmen; Ellsworth, Edmund; Hansen, Paul Robert; Ewin, Richard; Damborg, Peter; Watts, Jeffrey L

2018-06-06

Antifolates targeting folate biosynthesis within the shikimate-chorismate-folate metabolic pathway are ideal and selective antimicrobials, since higher eukaryotes lack this pathway and rely on an exogenous source of folate. Resistance to the available antifolates, inhibiting the folate pathway, underlines the need for novel antibiotic scaffolds and molecular targets. While para-aminobenzoic acid synthesis within the chorismate pathway constitutes a novel molecular target for antifolates, abyssomicins are its first known natural inhibitors. This review describes the abyssomicin family, a novel spirotetronate polyketide Class I antimicrobial. It summarizes synthetic and biological studies, structural, biosynthetic, and biological properties of the abyssomicin family members. This paper aims to explain their molecular target, mechanism of action, structure⁻activity relationship, and to explore their biological and pharmacological potential. Thirty-two natural abyssomicins and numerous synthetic analogues have been reported. The biological activity of abyssomicins includes their antimicrobial activity against Gram-positive bacteria and mycobacteria, antitumor properties, latent human immunodeficiency virus (HIV) reactivator, anti-HIV and HIV replication inducer properties. Their antimalarial properties have not been explored yet. Future analoging programs using the structure⁻activity relationship data and synthetic approaches may provide a novel abyssomicin structure that is active and devoid of cytotoxicity. Abyssomicin J and atrop- o -benzyl-desmethylabyssomicin C constitute promising candidates for such programs.

Nonreductive chemical release of intact N-glycans for subsequent labeling and analysis by mass spectrometry.

PubMed

Yuan, Jiangbei; Wang, Chengjian; Sun, Yujiao; Huang, Linjuan; Wang, Zhongfu

2014-10-01

A novel strategy is proposed, using cost-saving chemical reactions to generate intact free reducing N-glycans and their fluorescent derivatives from glycoproteins for subsequent analysis. N-Glycans without core α-1,3-linked fucose are released in reducing form by selective hydrolysis of the N-type carbohydrate-peptide bond of glycoproteins under a set of optimized mild alkaline conditions and are comparable to those released by commonly used peptide-N-glycosidase (PNGase) F in terms of yield without any detectable side reaction (peeling or deacetylation). The obtained reducing glycans can be routinely derivatized with 2-aminobenzoic acid (2-AA), 1-phenyl-3-methyl-5-pyrazolone (PMP), and potentially some other fluorescent reagents for comprehensive analysis. Alternatively, the core α-1,3-fucosylated N-glycans are released in mild alkaline medium and derivatized with PMP in situ, and their yields are comparable to those obtained using commonly used PNGase A without conspicuous peeling reaction or any detectable deacetylation. Using this new technique, the N-glycans of a series of purified glycoproteins and complex biological samples were successfully released and analyzed by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS), demonstrating its general applicability to glycomic studies. Copyright © 2014 Elsevier Inc. All rights reserved.

Investigations on aberrant glycosylation of glycosphingolipids in colorectal cancer tissues using liquid chromatography and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS).

PubMed

Holst, Stephanie; Stavenhagen, Kathrin; Balog, Crina I A; Koeleman, Carolien A M; McDonnell, Liam M; Mayboroda, Oleg A; Verhoeven, Aswin; Mesker, Wilma E; Tollenaar, Rob A E M; Deelder, André M; Wuhrer, Manfred

2013-11-01

Cancer is a leading cause of death and alterations of glycosylation are characteristic features of malignant cells. Colorectal cancer is one of the most common cancers and its exact causes and biology are not yet well understood. Here, we compared glycosylation profiles of colorectal tumor tissues and corresponding control tissues of 13 colorectal cancer patients to contribute to the understanding of this cancer. Using MALDI-TOF(/TOF)-MS and 2-dimensional LC-MS/MS we characterized enzymatically released and 2-aminobenzoic acid labeled glycans from glycosphingolipids. Multivariate data analysis revealed significant differences between tumor and corresponding control tissues. Main discriminators were obtained, which represent the overall alteration in glycosylation of glycosphingolipids during colorectal cancer progression, and these were found to be characterized by (1) increased fucosylation, (2) decreased acetylation, (3) decreased sulfation, (4) reduced expression of globo-type glycans, as well as (5) disialyl gangliosides. The findings of our current research confirm former reports, and in addition expand the knowledge of glycosphingolipid glycosylation in colorectal cancer by revealing new glycans with discriminative power and characteristic, cancer-associated glycosylation alterations. The obtained discriminating glycans can contribute to progress the discovery of biomarkers to improve diagnostics and patient treatment.

Investigations on Aberrant Glycosylation of Glycosphingolipids in Colorectal Cancer Tissues Using Liquid Chromatography and Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry (MALDI-TOF-MS)*

PubMed Central

Holst, Stephanie; Stavenhagen, Kathrin; Balog, Crina I. A.; Koeleman, Carolien A. M.; McDonnell, Liam M.; Mayboroda, Oleg A.; Verhoeven, Aswin; Mesker, Wilma E.; Tollenaar, Rob A. E. M.; Deelder, André M.; Wuhrer, Manfred

2013-01-01

Cancer is a leading cause of death and alterations of glycosylation are characteristic features of malignant cells. Colorectal cancer is one of the most common cancers and its exact causes and biology are not yet well understood. Here, we compared glycosylation profiles of colorectal tumor tissues and corresponding control tissues of 13 colorectal cancer patients to contribute to the understanding of this cancer. Using MALDI-TOF(/TOF)-MS and 2-dimensional LC-MS/MS we characterized enzymatically released and 2-aminobenzoic acid labeled glycans from glycosphingolipids. Multivariate data analysis revealed significant differences between tumor and corresponding control tissues. Main discriminators were obtained, which represent the overall alteration in glycosylation of glycosphingolipids during colorectal cancer progression, and these were found to be characterized by (1) increased fucosylation, (2) decreased acetylation, (3) decreased sulfation, (4) reduced expression of globo-type glycans, as well as (5) disialyl gangliosides. The findings of our current research confirm former reports, and in addition expand the knowledge of glycosphingolipid glycosylation in colorectal cancer by revealing new glycans with discriminative power and characteristic, cancer-associated glycosylation alterations. The obtained discriminating glycans can contribute to progress the discovery of biomarkers to improve diagnostics and patient treatment. PMID:23878401

Bladder cancer detection using a peptide substrate of the 20S proteasome.

PubMed

Gruba, Natalia; Wysocka, Magdalena; Brzezińska, Magdalena; Dębowski, Dawid; Sieńczyk, Marcin; Gorodkiewicz, Ewa; Guszcz, Tomasz; Czaplewski, Cezary; Rolka, Krzysztof; Lesner, Adam

2016-08-01

The 20S catalytic core of the human 26S proteasome can be secreted from cells, and high levels of extracellular 20S proteasome have been linked to many types of cancers and autoimmune diseases. Several diagnostic approaches have been developed that detect 20S proteasome activity in plasma, but these suffer from problems with efficiency and sensitivity. In this report, we describe the optimization and synthesis of an internally quenched fluorescent substrate of the 20S proteasome, and investigate its use as a potential diagnostic test in bladder cancer. This peptide, 2-aminobenzoic acid (ABZ)-Val-Val-Ser-Tyr-Ala-Met-Gly-Tyr(3-NO2 )-NH2 , is cleaved by the chymotrypsin 20S proteasome subunit and displays an excellent specificity constant value (9.7 × 10(5)  m(-1) ·s(-1) ) and a high kcat (8 s(-1) ). Using this peptide, we identified chymotrypsin-like proteasome activity in the majority of urine samples obtained from patients with bladder cancer, whereas the proteasome activity in urine samples from healthy volunteers was below the detection limit (0.5 pm). These findings were confirmed by an inhibitory study and immunochemistry methods. © 2016 Federation of European Biochemical Societies.

Electrochemical immunosensor for ethinylestradiol using diazonium salt grafting onto silver nanoparticles-silica-graphene oxide hybrids.

PubMed

Cincotto, Fernando H; Martínez-García, Gonzalo; Yáñez-Sedeño, Paloma; Canevari, Thiago C; Machado, S A S; Pingarrón, José M

2016-01-15

This work describes the preparation of an electrochemical immunosensor for ethinylestradiol (EE2) based on grafting of diazonium salt of 4-aminobenzoic acid onto a glassy carbon electrode modified with silver nanoparticles/SiO2/graphene oxide hybrid followed by covalent binding of anti-ethinylestradiol (anti-EE2) to activated carboxyl groups. A competitive immunoassay was developed for the determination of the hormone using peroxidase-labeled ethinylestradiol (HRP-EE2) and measurement of the amperometric response at -200mV in the presence of hydroquinone (HQ) as redox mediator. The calibration curve for EE2 exhibited a linear range between 0.1 and 50ng/mL (r(2)=0.996), with a detection limit of 65pg/mL. Interference studies with other hormones related with EE2 revealed the practical specificity of the developed method for the analyte. A good reproducibility, with RSD=4.5% (n=10) was also observed. The operating stability of a single bioelectrode modified with anti-EE2 was maintained at least for 15 days when it was stored at 4°C under humid conditions between measurements. The developed immunosensor was applied to the analysis of spiked urine with good results. Copyright © 2015 Elsevier B.V. All rights reserved.

Identifying target processes for microbial electrosynthesis by elementary mode analysis.

PubMed

Kracke, Frauke; Krömer, Jens O

2014-12-30

Microbial electrosynthesis and electro fermentation are techniques that aim to optimize microbial production of chemicals and fuels by regulating the cellular redox balance via interaction with electrodes. While the concept is known for decades major knowledge gaps remain, which make it hard to evaluate its biotechnological potential. Here we present an in silico approach to identify beneficial production processes for electro fermentation by elementary mode analysis. Since the fundamentals of electron transport between electrodes and microbes have not been fully uncovered yet, we propose different options and discuss their impact on biomass and product yields. For the first time 20 different valuable products were screened for their potential to show increased yields during anaerobic electrically enhanced fermentation. Surprisingly we found that an increase in product formation by electrical enhancement is not necessarily dependent on the degree of reduction of the product but rather the metabolic pathway it is derived from. We present a variety of beneficial processes with product yield increases of maximal 36% in reductive and 84% in oxidative fermentations and final theoretical product yields up to 100%. This includes compounds that are already produced at industrial scale such as succinic acid, lysine and diaminopentane as well as potential novel bio-commodities such as isoprene, para-hydroxybenzoic acid and para-aminobenzoic acid. Furthermore, it is shown that the way of electron transport has major impact on achievable biomass and product yields. The coupling of electron transport to energy conservation could be identified as crucial for most processes. This study introduces a powerful tool to determine beneficial substrate and product combinations for electro-fermentation. It also highlights that the maximal yield achievable by bio electrochemical techniques depends strongly on the actual electron transport mechanisms. Therefore it is of great importance to reveal the involved fundamental processes to be able to optimize and advance electro fermentations beyond the level of lab-scale studies.

Synthesis and oxidation of CpIrIII compounds: functionalization of a Cp methyl group.

PubMed

Park-Gehrke, Lisa S; Freudenthal, John; Kaminsky, Werner; Dipasquale, Antonio G; Mayer, James M

2009-03-21

[CpIrCl(2)](2) () and new CpIr(III)(L-L)X complexes (L-L = N-O or C-N chelating ligands; X = Cl, I, Me) have been prepared and their reactivity with two-electron chemical oxidants explored. Reaction of with PhI(OAc)(2) in wet solvents yields a new chloro-bridged dimer in which each of the Cp ligands has been singly acetoxylated to form [Cp(OAc)Ir(III)Cl(2)](2) () (Cp(OAc) = eta(5)-C(5)Me(4)CH(2)OAc). Complex and related carboxy- and alkoxy-functionalized Cp(OR) complexes can also be prepared from plus (PhIO)(n) and ROH. [Cp(OAc)Ir(III)Cl(2)](2) () and the methoxy analogue [Cp(OMe)Ir(III)Cl(2)](2) () have been structurally characterized. Treatment of [CpIrCl(2)](2) () with 2-phenylpyridine yields CpIr(III)(ppy)Cl () (ppy = cyclometallated 2-phenylpyridyl) which is readily converted to its iodide and methyl analogues CpIr(III)(ppy)I and CpIr(III)(ppy)Me (). CpIr(III) complexes were also prepared with N-O chelating ligands derived from anthranilic acid (2-aminobenzoic acid) and alpha-aminoisobutyric acid (H(2)NCMe(2)COOH), ligands chosen to be relatively oxidation resistant. These complexes and were reacted with potential two-electron oxidants including PhI(OAc)(2), hexachlorocyclohexadienone (C(6)Cl(6)O), N-fluoro-2,4,6-trimethylpyridinium (Me(3)pyF(+)), [Me(3)O]BF(4) and MeOTf (OTf = triflate, CF(3)SO(3)). Iridium(V) complexes were not observed or implicated in these reactions, despite the similarity of the potential products to known CpIr(V) species. The carbon electrophiles [Me(3)O]BF(4) and MeOTf appear to react preferentially at the N-O ligands, to give methyl esters in some cases. Overall, the results indicate that Cp is not inert under oxidizing conditions and is therefore not a good supporting ligand for oxidizing organometallic complexes.

Unique anthranilic acid chemistry facilitates profiling and characterization of Ser/Thr-linked sugar chains following hydrazinolysis.

PubMed

Anumula, Kalyan Rao

2008-02-01

A novel method for the analysis of Ser/Thr-linked sugar chains was made possible by the virtue of unique anthranilic acid (AA, 2-aminobenzoic acid [2AA]) chemistry for labeling carbohydrates in aqueous salt solutions (K. R. Anumula, Anal. Biochem. 350 (2006) 1-23). The protocol for profiling of Ser/Thr carbohydrates by hydrazinolysis was made simple by eliminating intermediary isolation steps involved in a sample preparation such as desalting and various chromatographic purification schemes. A 6-h hydrazinolysis was carried out at 60 degrees C for O-linked oligosaccharides and at 95 degrees C for total oligosaccharides (N-linked with some O-linked). Following evaporation of hydrazine (<10 min), the oligosaccharides were N-acetylated and derivatized with AA in the same reaction mixture containing salts. Presumably, the glycosyl-hydrazines/hydrazones present in the mixture did not interfere with AA labeling. Because AA is the most fluorescent and highly reactive tag for labeling carbohydrates, the procedures described are suitable for the analysis of a limited amount of samples ( approximately 5 microg) by the current high-resolution high-performance liquid chromatography (HPLC) methods. HPLC conditions developed for the separation of O-linked sugar chains based on size on an amide column were satisfactory for quantitative profiling and characterization. Common O-linked sugar chains found in fetuin, equine chorionic gonadotropin, and glycophorin can be analyzed in less than 50 min. In addition, these fast profiling methods were comparable to profiling by PNGase F (peptide N-glycosidase from Flavobacterium meningosepticum) digestion in terms of time, effort, and simplicity and also were highly reproducible for routine testing. The procedures for the release of sugar chains by hydrazinolysis at the microgram level, labeling with fluorescent tag AA, and profiling by HPLC should be useful in characterization of carbohydrates found in glycoproteins.

Neurotensin-metabolizing peptidases in rat fundus plasma membranes.

PubMed

Checler, F; Barelli, H; Kwan, C Y; Kitabgi, P; Vincent, J P

1987-08-01

The mechanisms by which neurotensin (NT) was inactivated by rat fundus plasma membranes were characterized. Primary inactivating cleavages occurred at the Arg8-Arg9, Pro10-Tyr11, and Ile12-Leu13 peptidyl bonds. Hydrolysis at the Arg8-Arg9 bond was fully abolished by the use of N-[1(R,S)-carboxy-2-phenylethyl]-alanyl-alanyl-phenylalanine-p- aminobenzoate, a result indicating the involvement at this site of a recently purified soluble metallopeptidase. Hydrolysis of the Pro10-Tyr11 bond was totally resistant to N-benzyloxycarbonyl-prolyl-prolinal and thiorphan, an observation suggesting that the peptidase responsible for this cleavage was different from proline endopeptidase and endopeptidase 24.11 and might correspond to a NT-degrading neutral metallopeptidase recently isolated from rat brain synaptic membranes. The enzyme acting at the Ile12-Leu13 bond has not yet been identified. Secondary cleavages occurring on NT degradation products were mainly generated by bestatin-sensitive aminopeptidases and post-proline dipeptidyl aminopeptidase. The content in NT-metabolizing peptidases present in rat fundus plasma membranes is compared with that previously established for purified rat brain synaptic membranes.

Stable isotopic labeling-based quantitative targeted glycomics (i-QTaG).

PubMed

Kim, Kyoung-Jin; Kim, Yoon-Woo; Kim, Yun-Gon; Park, Hae-Min; Jin, Jang Mi; Hwan Kim, Young; Yang, Yung-Hun; Kyu Lee, Jun; Chung, Junho; Lee, Sun-Gu; Saghatelian, Alan

2015-01-01

Mass spectrometry (MS) analysis combined with stable isotopic labeling is a promising method for the relative quantification of aberrant glycosylation in diseases and disorders. We developed a stable isotopic labeling-based quantitative targeted glycomics (i-QTaG) technique for the comparative and quantitative analysis of total N-glycans using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We established the analytical procedure with the chemical derivatizations (i.e., sialic acid neutralization and stable isotopic labeling) of N-glycans using a model glycoprotein (bovine fetuin). Moreover, the i-QTaG using MALDI-TOF MS was evaluated with various molar ratios (1:1, 1:2, 1:5) of (13) C6 /(12) C6 -2-aminobenzoic acid-labeled glycans from normal human serum. Finally, this method was applied to direct comparison of the total N-glycan profiles between normal human sera (n = 8) and prostate cancer patient sera (n = 17). The intensities of the N-glycan peaks from i-QTaG method showed a good linearity (R(2) > 0.99) with the amount of the bovine fetuin glycoproteins. The ratios of relative intensity between the isotopically 2-AA labeled N-glycans were close to the theoretical molar ratios (1:1, 1:2, 1:5). We also demonstrated that the up-regulation of the Lewis antigen (~82%) in sera from prostate cancer patients. In this proof-of-concept study, we demonstrated that the i-QTaG method, which enables to achieve a reliable comparative quantitation of total N-glycans via MALDI-TOF MS analysis, has the potential to diagnose and monitor alterations in glycosylation associated with disease states or biotherapeutics. © 2015 American Institute of Chemical Engineers.

Aggravation of cold-induced injury in Vero-B4 cells by RPMI 1640 medium - identification of the responsible medium components.

PubMed

Pless-Petig, Gesine; Metzenmacher, Martin; Türk, Tobias R; Rauen, Ursula

2012-10-10

In modern biotechnology, there is a need for pausing cell lines by cold storage to adapt large-scale cell cultures to the variable demand for their products. We compared various cell culture media/solutions for cold storage of Vero-B4 kidney cells, a cell line widely used in biotechnology. Cold storage in RPMI 1640 medium, a recommended cell culture medium for Vero-B4 cells, surprisingly, strongly enhanced cold-induced cell injury in these cells in comparison to cold storage in Krebs-Henseleit buffer or other cell culture media (DMEM, L-15 and M199). Manufacturer, batch, medium supplements and the most likely components with concentrations outside the range of the other media/solutions (vitamin B12, inositol, biotin, p-aminobenzoic acid) did not cause this aggravation of cold-induced injury in RPMI 1640. However, a modified Krebs-Henseleit buffer with a low calcium concentration (0.42 mM), a high concentration of inorganic phosphate (5.6 mM), and glucose (11.1 mM; i.e. concentrations as in RPMI 1640) evoked a cell injury and loss of metabolic function corresponding to that observed in RPMI 1640. Deferoxamine improved cell survival and preserved metabolic function in modified Krebs-Henseleit buffer as well as in RPMI 1640. Similar Ca2+ and phosphate concentrations did not increase cold-induced cell injury in the kidney cell line LLC-PK1, porcine aortic endothelial cells or rat hepatocytes. However, more extreme conditions (Ca2+ was nominally absent and phosphate concentration raised to 25 mM as in the organ preservation solution University of Wisconsin solution) also increased cold-induced injury in rat hepatocytes and porcine aortic endothelial cells. These data suggest that the combination of low calcium and high phosphate concentrations in the presence of glucose enhances cold-induced, iron-dependent injury drastically in Vero-B4 cells, and that a tendency for this pathomechanism also exists in other cell types.

Reactive low temperature plasma ionization mass spectrometry for the determination of organic UV filters in personal care products.

PubMed

Ding, Xuelu; Gerbig, Stefanie; Spengler, Bernhard; Schulz, Sabine

2018-02-01

Organic UV filters in personal care products (PCPs) have been persistently reported as a potential threat to human health. In order to guarantee consumers ' safety, the dose of these compounds in PCPs needs to be monitored. Here, a methodology based on reactive low temperature plasma ionization (LTP) mass spectrometry (MS) has been developed for the determination of common organic UV filters in PCPs including benzophenone-3, ethylhexyl dimethyl p-aminobenzoic acid, ethylhexyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, and ethylhexyl salicylate. The experiments were carried out in transmission geometry where the LTP ion source, samples loaded on a stainless steel mesh, and the MS inlet were aligned coaxially. Four chemicals, ammonia, ammonium formate, aniline, and methylamine were considered as reactive additives allowing reactions with the UV filters through different mechanisms. Methylamine-induced reactive LTP-MS showed the most prominent improvement on the detection of UV filter compounds. Compared to direct LTP-MS, the developed method improved the detection limits of UV filters more than 10 fold. Moreover, the method enabled fast semi-quantitative screening of UV filters in authentic PCPs. Concentrations of active ingredients in eight authentic PCPs as determined with reactive LTP-MS were found comparable to values offered by the cosmetic companies and corresponding HPLC data. The methodology provides high throughput analysis (70s per sample) and sensitive identification of organic UV filters. Lowest detectable concentrations ranged from 0.13µg/g for 4-methylbenzylidene camphor to 7.67µg/g for octocrylene in spiked cream. In addition, it shows the potential to be used as a screening tool for legal authentications of these chemicals in the future due to its semi-quantitative determination of UV filters in PCPs without tedious sample preparation and time-consuming chromatographic separation. Copyright © 2017 Elsevier B.V. All rights reserved.

Advances in analytical methods and occurrence of organic UV-filters in the environment--A review.

PubMed

Ramos, Sara; Homem, Vera; Alves, Arminda; Santos, Lúcia

2015-09-01

UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more frequently and deeply. Copyright © 2015 Elsevier B.V. All rights reserved.

Occurrence, fate and risk assessment of personal care products in river-groundwater interface.

PubMed

Serra-Roig, Maria Pau; Jurado, Anna; Díaz-Cruz, M Silvia; Vázquez-Suñé, Enric; Pujades, Estanislao; Barceló, Damià

2016-10-15

This work presents the occurrence and fate of selected personal care products (PCPs) in the urban river-groundwater interface. To this end, urban river and groundwater samples were collected in Sant Adrià del Besòs (NE of Spain) and a total of 16 PCPs were analyzed including benzophenone derivatives, camphor derivatives, p-aminobenzoic acid derivatives, triazoles and parabens in three different campaigns (from May 2010 to July 2014). These compounds reach the aquifer through the recharge of Besòs River that receives large amounts of effluents from waste water treatment plants. Results have shown that most of the compounds were not or barely detected (maximum concentrations around 200ng/L) in groundwater samples during the different sampling campaigns. Only two triazoles, namely benzotriazole (BZT) and methyl benzotriazol (MeBZT) were found at high concentrations in groundwater samples (maximum concentration around 2000ng/L). The fate of PCPs in the aquifer was assessed using mixing analysis considering the seasonal variability of the Besòs River. Overall, measured groundwater concentrations were significantly much lower than those estimated by the mixing of the river water. This observation suggested that most of the PCPs are naturally removed when river water infiltrates the aquifer. However, some compounds were more persistent in the aquifer. These compounds were in descending order: the triazoles BZT and MeBZT followed by the camphor derivative 4MBC and the paraben MePB. The measured concentrations allowed us to assess the environmental risk posed by the selected UV-filters and parabens in the river and groundwater samples. Hazard Quotients (HQs) for different aquatic species were calculated in order to characterize the ecotoxicity potential of the studied compounds in the river-groundwater interface. HQ values were always below 1 indicating that at the concentrations observed in the surface or aquifer water of Besòs River these compounds pose no risk to the selected aquatic organisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Contamination sources and distribution patterns of pharmaceuticals and personal care products in Alpine rivers strongly affected by tourism.

PubMed

Mandaric, Ladislav; Diamantini, Elena; Stella, Elisa; Cano-Paoli, Karina; Valle-Sistac, Jennifer; Molins-Delgado, Daniel; Bellin, Alberto; Chiogna, Gabriele; Majone, Bruno; Diaz-Cruz, M Silvia; Sabater, Sergi; Barcelo, Damia; Petrovic, Mira

2017-07-15

Knowledge regarding the impact of tourism on the emergence of pharmaceuticals and personal care products (PPCPs) in Alpine river waters is limited and scarce. Therefore, a study on the occurrence patterns and spatiotemporal variability of 105 PPCPs in an Alpine river basin located in the Trentino-Alto Adige region (North-Eastern Italy) has been conducted. We observed that the total concentration of analyzed PPCPs was generally higher in all sampling sites during winter than in the summer. The analysis of tourist data revealed that during both sampling campaigns the number of tourists was lower in the downstream sites in comparison with the upstream area of the basin (Val di Sole). Particularly, sampling sites located near important tourist resorts have shown the highest abundance of the PPCPs during winter, being analgesics/anti-inflammatories, antihypertensives and antibiotics the most abundant pharmaceutically active compounds (PhACs). Diclofenac showed the highest concentration amongst PhACs, reaching concentrations up to 675ngL -1 in the sampling site situated downstream of the Tonale wastewater treatment plant (WWTP). Antihypertensives were found at concentrations >300ngL -1 , while antibiotics were quantified up to 196ngL -1 , respectively. Amongst personal care products (PCPs), the most abundant compound was octyl-dimethyl-p-aminobenzoic acid (ODPABA) with concentrations reaching up to 748ngL -1 in the sampling site situated within the Rotaliana district. In general, concentrations and detection frequencies were higher in water than in the sediment samples. The most frequently detected PhACs in sediments from both sampling campaigns were antibiotics, while amongst PCPs in sediments, octocrylene (OC) showed the highest concentration in both sampling campaigns. As a result, this study highlights the potential impact of tourism on the water quality of the Alpine aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Substrate and inhibitor studies of thermolysin-like neutral metalloendopeptidase from kidney membrane fractions. Comparison with bacterial thermolysin.

PubMed

Pozsgay, M; Michaud, C; Liebman, M; Orlowski, M

1986-03-25

The inhibitory constants of a series of synthetic N-carboxymethyl peptide inhibitors and the kinetic parameters (Km, kcat, and kcat/Km) of a series of model synthetic substrates were determined for the membrane-bound kidney metalloendopeptidase isolated from rabbit kidney and compared with those of bacterial thermolysin. The two enzymes show striking similarities with respect to structural requirements for substrate binding to the hydrophobic pocket at the S1' subsite of the active site. Both enzymes showed the highest reaction rates with substrates having leucine residues in this position while phenylalanine residues gave the lowest Km. The two enzymes were also inhibited by the same N-carboxymethyl peptide inhibitors. Although the mammalian enzyme was more susceptible to inhibition than its bacterial counterpart, structural variations in the inhibitor molecules affected the inhibitory constants for both enzymes in a similar manner. The two enzymes differed significantly, however, with respect to the effect of structural changes in the P1 and P2' positions of the substrate on the kinetic parameters of the reaction. The mammalian enzyme showed the highest reaction rates and specificity constants with substrates having the sequence -Phe-Gly-Phe- or -Phe-Ala-Phe- in positions P2, P1, and P1', respectively, while the sequence -Ala-Phe-Phe- was the most favored by the bacterial enzyme. The sequence -Gly-Gly-Phe- as found in enkephalins was not favored by either of the enzymes. Of the substrates having an aminobenzoate group in the P2' position, the mammalian enzyme favored those with the carboxyl group in the meta position while the bacterial enzyme favored those with the carboxyl group in the para position.(ABSTRACT TRUNCATED AT 250 WORDS)

Gateways to clinical trials.

PubMed

Bayés, M; Rabasseda, X; Prous, J R

2005-04-01

Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables has been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity. prous.com. This issue focuses on the following selection of drugs: ABX-IL-8, Acclaim, adalimumab, AGI-1067, alagebrium chloride, alemtuzumab, Alequel, Androgel, anti-IL-12 MAb, AOD-9604, aripiprazole, atomoxetine hydrochloride; Biphasic insulin aspart, bosentan, botulinum toxin type B, bovine lactoferrin, brivudine; Cantuzumab mertansine, CB-1954, CDB-4124, CEA-TRICOM, choriogonadotropin alfa, cilansetron, CpG-10101, CpG-7909, CTL-102, CTL-102/CB-1954; DAC:GRF, darbepoetin alfa, davanat-1, decitabine, del-1 Genemedicine, dexanabinol, dextofisopam, dnaJP1, dronedarone hydrochloride, dutasteride; Ecogramostim, eletriptan, emtricitabine, EPI-hNE-4, eplerenone, eplivanserin fumarate, erlotinib hydrochloride, ertapenem sodium, escitalopram oxalate, esomeprazole magnesium, etoricoxib, ezetimibe; Falecalcitriol, fingolimod hydrochloride; Gepirone hydrochloride; HBV-ISS, HSV-2 theracine, human insulin; Imatinib mesylate, Indiplon, insulin glargine, ISAtx-247; L612 HuMAb, levodopa/carbidopa/entacapone, lidocaine/prilocaine, LL-2113AD, lucinactant, LY-156735; Meclinertant, metelimumab, morphine hydrochloride, morphine-6-glucuronide; Natalizumab, nimotuzumab, NX-1207, NYVAC-HIV C; Omalizumab, onercept, osanetant; PABA, palosuran sulfate, parathyroid hormone (human recombinant), parecoxib sodium, PBI-1402, PCK-3145, peginterferon alfa-2a, peginterferon alfa-2b, peginterferon alfa-2b/ribavirin, pemetrexed disodium, pimecrolimus, PINC, pregabalin; Ramelteon, rasagiline mesilate, rasburicase, rimonabant hydrochloride, RO-0098557, rofecoxib, rosiglitazone maleate/metformin hydrochloride; Safinamide mesilate, SHL-749, sitaxsentan sodium, sparfosic acid, SprayGel, squalamine, St. John's Wort extract, synthetic human secretin; Taxus, telavancin hydrochloride, telithromycin, temoporfin, tenofovir disoproxil fumarate, tenofovir disoproxil fumarate/emtricitabine, teriparatide, testosterone gel, TG-1024, tirapazamine, travoprost, travoprost/timolol; Valdecoxib, valganciclovir hydrochloride, voriconazole; Ximelagatran.

Reductive ring closure methodology toward heteroacenes bearing a dihydropyrrolo[3,2-b]pyrrole core: scope and limitation.

PubMed

Qiu, Li; Wang, Xiao; Zhao, Na; Xu, Shiliang; An, Zengjian; Zhuang, Xuhui; Lan, Zhenggang; Wen, Lirong; Wan, Xiaobo

2014-12-05

A newly developed reductive ring closure methodology to heteroacenes bearing a dihydropyrrolo[3,2-b]pyrrole core was systematically studied for its scope and limitation. The methodology involves (i) the cyclization of an o-aminobenzoic acid ester derivative to give an eight-membered cyclic dilactam, and (ii) the conversion of the dilactams into the corresponding diimidoyl chloride, which undergoes (iii) reductive ring closure to install the dihydropyrrolo[3,2-b]pyrrole core. The first step of the methodology plays the key role due to its substrate limitation, which suffers from the competition of oligomerization and hydrolysis. All the dilactams could successfully convert to the corresponding diimidoyl chlorides, most of which succeeded to give the dihydropyrrolo[3,2-b]pyrrole core. The influence of the substituents and the elongation of conjugated length on the photophysical properties of the obtained heteroacenes were then investigated systematically using UV-vis spectroscopy and cyclic voltammetry. It was found that chlorination and fluorination had quite a different effect on the photophysical properties of the heteroacene, and the ring fusing pattern also had a drastic influence on the band gap of the heteroacene. The successful preparation of a series of heteroacenes bearing a dihydropyrrolo[3,2-b]pyrrole core would provide a wide variety of candidates for further fabrication of organic field-effect transistor devices.

Chromatographic determination of nanomolar cyanate concentrations in estuarine and sea waters by precolumn fluorescence derivatization.

PubMed

Widner, Brittany; Mulholland, Margaret R; Mopper, Kenneth

2013-07-16

Recent studies suggest that cyanate (OCN(-)) is a potentially important source of reduced nitrogen (N) available to support the growth of aquatic microbes and, thus, may play a role in aquatic N cycling. However, aquatic OCN(-) distributions have not been previously described because of the lack of a suitable assay for measuring OCN(-) concentrations in natural waters. Previous methods were designed to quantify OCN(-) in aqueous samples with much higher reduced N concentrations (micromolar levels) than those likely to be found in natural waters (nanomolar levels). We have developed a method to quantify OCN(-) in dilute, saline environments. In the method described here, OCN(-) in aqueous solution reacts with 2-aminobenzoic acid to produce a highly fluorescent derivative, 2,4-quinazolinedione, which is then quantified using high performance liquid chromatography. Derivatization conditions were optimized to simultaneously minimize the reagent blank and maximize 2,4-quinazolinedione formation (>90% reaction yield) in estuarine and seawater matrices. A limit of detection (LOD) of 0.4 nM was achieved with only minor matrix effects. We applied this method to measure OCN(-) concentrations in estuarine and seawater samples from the Chesapeake Bay and coastal waters from the mid-Atlantic region. OCN(-) concentrations ranged from 0.9 to 41 nM. We determined that OCN(-) concentrations were stable in 0.2 μm filtered seawater samples stored at -80 °C for up to nine months.

Sensitive electrochemical immunosensor for α-synuclein based on dual signal amplification using PAMAM dendrimer-encapsulated Au and enhanced gold nanoparticle labels.

PubMed

An, Yarui; Jiang, Xiaoli; Bi, Wenji; Chen, Hua; Jin, Litong; Zhang, Shengping; Wang, Chuangui; Zhang, Wen

2012-02-15

A novel electrochemical immunosensor for sensitive detection of α-synuclein (α-SYN), a very important neuronal protein, has been developed based on dual signal amplification strategy. Herein, G4-polyamidoamine dendrimer-encapsulated Au nanoparticles (PAMAM-Au nanocomposites) were covalently bound on the poly-o-aminobenzoic acid (poly-o-ABA), which was initially electropolymerized on the electrode surface to perform abundant carboxyl groups. The formed immunosensor platform, PAMAM-Au, was proved to provide numerous amino groups to allow highly dense immobilization of antigen, and facilitate the improvement of electrochemical responses as well. Subsequently, the enhanced gold nanoparticle labels ({HRP-Ab(2)-GNPs}) were fabricated by immobilizing horseradish peroxidase-secondary antibody (HRP-Ab(2)) on the surface of gold nanoparticles (GNPs). After an immunoassay process, the {HRP-Ab(2)-GNPs} labels were introduced onto the electrode surface, and produced an electrocatalytic response by reduction of hydrogen peroxide (H(2)O(2)) in the presence of enzymatically oxidized thionine. On the basis of the dual signal amplification of PAMAM-Au and {HRP-Ab(2)-GNPs} labels, the designed immunosensor displayed an excellent analytical performance with high sensitivity and stability. This developed strategy was successfully proved as a simple, cost-effective method, and could be easily extended to other protein analysis schemes. Copyright © 2011 Elsevier B.V. All rights reserved.

Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes

NASA Astrophysics Data System (ADS)

Bhattacharjee, Chira R.; Goswami, Pankaj; Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh

2011-05-01

Two new mixed-ligand iron(III) complexes, [Fe(L n)(acac)(C 2H 5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac) 3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H 2L 1) or 2-aminobenzoic acid (H 2L 2). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L n)(acac)X] ( n = 1, 2; X = Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, 1H and 13C NMR spectroscopy. Room temperature magnetic susceptibility measurements ( μeff ˜ 5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (Δ Ep > 100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential ( E1/2) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level.

Quantification and characterization of enzymatically produced hyaluronan with fluorophore-assisted carbohydrate electrophoresis.

PubMed

Kooy, Floor K; Ma, Muyuan; Beeftink, Hendrik H; Eggink, Gerrit; Tramper, Johannes; Boeriu, Carmen G

2009-01-15

Hyaluronan (HA) is a polysaccharide with high-potential medical applications, depending on the chain length and the chain length distribution. Special interest goes to homogeneous HA oligosaccharides, which can be enzymatically produced using Pasteurella multocida hyaluronan synthase (PmHAS). We have developed a sensitive, simple, and fast method, based on fluorophore-assisted carbohydrate electrophoresis (FACE), for characterization and quantification of polymerization products. A chromatographic pure fluorescent template was synthesized from HA tetrasaccharide (HA4) and 2-aminobenzoic acid. HA4-fluor and HA4 were used as template for PmHAS-mediated polymerization of nucleotide sugars. All products, fluorescent and nonfluorescent, were analyzed with gel electrophoresis and quantified using lane densitometry. Comparison of HA4- and HA4-fluor-derived polymers showed that the fluorophore did not negatively influence the PmHAS-mediated polymerization. Only even-numbered oligosaccharide products were observed using HA4-fluor or HA4 as template. The fluorophore intensity was linearly related to its concentration, and the limit of detection was determined to be 7.4pmol per product band. With this assay, we can now differentiate oligosaccharides of size range DP2 (degree of polymerization 2) to approximately DP400, monitor the progress of polymerization reactions, and measure subtle differences in polymerization rate. Quantifying polymerization products enables us to study the influence of experimental conditions on HA synthesis.

Jet-cooled electronic and vibrational spectroscopy of crown ethers: benzo-15-crown-5 ether and 4'-amino-benzo-15-crown-5 ether.

PubMed

Shubert, V Alvin; James, William H; Zwier, Timothy S

2009-07-16

Laser-induced fluorescence (LIF), ultraviolet hole-burning (UVHB), and resonant ion-dip infrared (RIDIR) spectroscopies were carried out on isolated benzo-15-crown-5 ether (B15C) and 4'-amino-benzo-15-crown-5 ether (ABC) cooled in a supersonic expansion. Three conformational isomers of B15C and four of ABC were observed and spectroscopically characterized. Full optimizations and harmonic frequency calculations were undertaken for the full set of almost 1700 conformational minima identified in a molecular mechanics force field search. When compared with TDDFT predictions, the S(0)-S(1) origin positions serve as a useful diagnostic of the conformation of the crown ether near the phenyl ring responsible for the UV absorption and to the position of the NH(2) substituent. In-plane orientations for the beta carbons produce red-shifted S(0)-S(1) origins, while out-of-plane "buckling" produces substantial blue shifts of 600 cm(-1) or more. Comparison between the alkyl CH stretch spectra of B15C and ABC divide the spectra into common subgroups shared by the two molecules. The high-frequency CH stretch transitions (above 2930 cm(-1)) reflect the number of CH...O interactions, which in turn track in a general way the degree of buckling of the crown. On this basis, assignments of each of the observed conformational isomers to a class of structure can be made. All the observed structures have some degree of buckling to them, indicating that in the absence of a strong-binding partner, the crown folds in on itself to gain additional stabilization from weak dispersive and CH...O interactions.

Modified short-term guinea pig sensitization tests for detecting contact allergens as an alternative to the conventional test.

PubMed

Yanagi, M; Hoya, M; Mori, M; Katsumura, Y

2001-03-01

The conventional adjuvant and patch test (APT) method of guinea pig sensitization testing was modified in 2 ways, s-APT and s-APT(2), in order to shorten the test period. These short-term test methods consist of 72-h closed application of test material with intradermal injection of emulsified Freund's complete adjuvant (E-FCA) for 1st induction, 48-h closed application of test material with (s-APT) or without (s-APT(2)) intradermal injection of E-FCA on the 7th day for 2nd induction, and open application on the 14th day for challenge. They were compared with conventional APT by using 8 allergenic chemicals (formaldehyde, nickel sulfate, cobalt sulfate, ethyl-p-aminobenzoate (benzocaine), isoeugenol, 2-mercaptobenzothiazole, 2,4-dinitrochlorobenzene (DNCB) and 1-phenylazo-2-naphthol (Sudan I)). The short-term methods gave similar results to those of conventional APT in terms of mean response, sensitization rate and sensitization potency (challenge concentration that induces a mean response equal to 1.0). Thus, our short-term methods, which are capable of evaluating skin sensitization within 17 days, are sufficiently sensitive to detect potentially hazardous contact allergens.

Profiling and characterization of sialylated N-glycans by 2D-HPLC (HIAX/PGC) with online orbitrap MS/MS and offline MSn.

PubMed

Hanneman, Andrew J S; Strand, James; Huang, Chi-Ting

2014-02-01

Glycosylation is a critical parameter used to evaluate protein quality and consistency. N-linked glycan profiling is fundamental to the support of biotherapeutic protein manufacturing from early stage process development through drug product commercialization. Sialylated glycans impact the serum half-life of receptor-Fc fusion proteins (RFPs), making their quality and consistency a concern during the production of fusion proteins. Here, we describe an analytical approach providing both quantitative profiling and in-depth mass spectrometry (MS)-based structural characterization of sialylated RFP N-glycans. Aiming to efficiently link routine comparability studies with detailed structural characterization, an integrated workflow was implemented employing fluorescence detection, online positive and negative ion tandem mass spectrometry (MS/MS), and offline static nanospray ionization-sequential mass spectrometry (NSI-MS(n)). For routine use, high-performance liquid chromatography profiling employs established fluorescence detection of 2-aminobenzoic acid derivatives (2AA) and hydrophilic interaction anion-exchange chromatography (HIAX) charge class separation. Further characterization of HIAX peak fractions is achieved by online (-) ion orbitrap MS/MS, offering the advantages of high mass accuracy and data-dependent MS/MS. As required, additional characterization uses porous graphitized carbon in the second chromatographic dimension to provide orthogonal (+) ion MS/MS spectra and buffer-free liquid chromatography peak eluants that are optimum for offline (+)/(-) NSI-MS(n) investigations to characterize low-abundance species and specific moieties including O-acetylation and sulfation. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Spectroscopic characterization of metal complexes of novel Schiff base. Synthesis, thermal and biological activity studies

NASA Astrophysics Data System (ADS)

Omar, M. M.; Mohamed, Gehad G.; Ibrahim, Amr A.

2009-07-01

Novel Schiff base (HL) ligand is prepared via condensation of 4-aminoantipyrine and 2-aminobenzoic acid. The ligand is characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analyses (TGA, DrTGA and DTA). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a uninegatively tridentate manner with NNO donor sites of the azomethine N, amino N and deprotonated caroxylic-O. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, ΔH*, ΔS* and ΔG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia Coli, Pseudomonas aeruginosa, Staphylococcus Pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Shciff base ligand against one or more bacterial species.

Solid-phase reductive amination for glycomic analysis.

PubMed

Jiang, Kuan; Zhu, He; Xiao, Cong; Liu, Ding; Edmunds, Garrett; Wen, Liuqing; Ma, Cheng; Li, Jing; Wang, Peng George

2017-04-15

Reductive amination is an indispensable method for glycomic analysis, as it tremendously facilitates glycan characterization and quantification by coupling functional tags at the reducing ends of glycans. However, traditional in-solution derivatization based approach for the preparation of reductively aminated glycans is quite tedious and time-consuming. Here, a simpler and more efficient strategy termed solid-phase reductive amination was investigated. The general concept underlying this new approach is to streamline glycan extraction, derivatization, and purification on non-porous graphitized carbon sorbents. Neutral and sialylated standard glycans were utilized to test the feasibility of the solid-phase method. As results, almost complete labeling of those glycans with four common labels of aniline, 2-aminobenzamide (2-AB), 2-aminobenzoic acid (2-AA) and 2-amino-N-(2-aminoethyl)-benzamide (AEAB) was obtained, and negligible desialylation occurred during sample preparation. The labeled glycans derived from glycoproteins showed excellent reproducibility in high performance liquid chromatography (HPLC) and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. Direct comparisons based on fluorescent absorbance and relative quantification using isotopic labeling demonstrated that the solid-phase strategy enabled 20-30% increase in sample recovery. In short, the solid-phase strategy is simple, reproducible, efficient, and sensitive for glycan analysis. This method was also successfully applied for N-glycan profiling of HEK 293 cells with MALDI-TOF MS, showing its attractive application in the high-throughput analysis of mammalian glycome. Published by Elsevier B.V.

Analytical characterization of ch14.18

PubMed Central

Kallarakal, Abraham T; Michiel, Dennis; Yang, Xiaoyi; Saptharishi, Nirmala; Jiang, Hengguang; Giardina, Steve; Gilly, John; Mitra, George

2012-01-01

Ch14.18 is a mouse-human chimeric monoclonal antibody to the disialoganglioside (GD2) glycolipid. In the clinic, this antibody has been shown to be effective in the treatment of children with high-risk neuroblastoma, either alone or in combination therapy. Extensive product characterization is a prerequisite to addressing the potential issues of product variability associated with process changes and manufacturing scale-up. Charge heterogeneity, glycosylation profile, molecular state and aggregation, interaction (affinity) with Fcγ receptors and functional or biological activities are a few of the critical characterization assays for assessing product comparability for this antibody. In this article, we describe the in-house development and qualification of imaged capillary isoelectric focusing to assess charge heterogeneity, analytical size exclusion chromatography with online static and dynamic light scattering (DLS), batch mode DLS for aggregate detection, biosensor (surface plasmon resonance)-based Fcγ receptor antibody interaction kinetics, N-glycoprofiling with PNGase F digestion, 2-aminobenzoic acid labeling and high performance liquid chromatography and N-glycan analysis using capillary electrophoresis. In addition, we studied selected biological activity assays, such as complement-dependent cytotoxicity. The consistency and reproducibility of the assays are established by comparing the intra-day and inter-day assay results. Applications of the methodologies to address stability or changes in product characteristics are also reported. The study results reveal that the ch14.18 clinical product formulated in phosphate-buffered saline at a concentration of 5 mg/ml and stored at 2–8°C is stable for more than five years. PMID:22327432

Identification of bottlenecks in Escherichia coli engineered for the production of CoQ(10).

PubMed

Cluis, Corinne P; Ekins, Andrew; Narcross, Lauren; Jiang, Heng; Gold, Nicholas D; Burja, Adam M; Martin, Vincent J J

2011-11-01

In this work, Escherichia coli was engineered to produce a medically valuable cofactor, coenzyme Q(10) (CoQ(10)), by removing the endogenous octaprenyl diphosphate synthase gene and functionally replacing it with a decaprenyl diphosphate synthase gene from Sphingomonas baekryungensis. In addition, by over-expressing genes coding for rate-limiting enzymes of the aromatic pathway, biosynthesis of the CoQ(10) precursor para-hydroxybenzoate (PHB) was increased. The production of isoprenoid precursors of CoQ(10) was also improved by the heterologous expression of a synthetic mevalonate operon, which permits the conversion of exogenously supplied mevalonate to farnesyl diphosphate. The over-expression of these precursors in the CoQ(10)-producing E. coli strain resulted in an increase in CoQ(10) content, as well as in the accumulation of an intermediate of the ubiquinone pathway, decaprenylphenol (10P-Ph). In addition, the over-expression of a PHB decaprenyl transferase (UbiA) encoded by a gene from Erythrobacter sp. NAP1 was introduced to direct the flux of DPP and PHB towards the ubiquinone pathway. This further increased CoQ(10) content in engineered E. coli, but decreased the accumulation of 10P-Ph. Finally, we report that the combined over-production of isoprenoid precursors and over-expression of UbiA results in the decaprenylation of para-aminobenzoate, a biosynthetic precursor of folate, which is structurally similar to PHB. Copyright © 2011 Elsevier Inc. All rights reserved.

Production and characterization of a camelid single domain antibody-urease enzyme conjugate for the treatment of cancer.

PubMed

Tian, Baomin; Wong, Wah Yau; Hegmann, Elda; Gaspar, Kim; Kumar, Praveen; Chao, Heman

2015-06-17

A novel immunoconjugate (L-DOS47) was developed and characterized as a therapeutic agent for tumors expressing CEACAM6. The single domain antibody AFAIKL2, which targets CEACAM6, was expressed in the Escherichia coli BL21 (DE3) pT7-7 system. High purity urease (HPU) was extracted and purified from Jack bean meal. AFAIKL2 was activated using N-succinimidyl [4-iodoacetyl] aminobenzoate (SIAB) as the cross-linker and then conjugated to urease. The activation and conjugation reactions were controlled by altering pH. Under these conditions, the material ratio achieved conjugation ratios of 8-11 antibodies per urease molecule, the residual free urease content was practically negligible (<2%), and high purity (>95%) L-DOS47 conjugate was produced using only ultradiafiltration to remove unreacted antibody and hydrolyzed cross-linker. L-DOS47 was characterized by a panel of analytical techniques including SEC, IEC, Western blot, ELISA, and LC-MS(E) peptide mapping. As the antibody-urease conjugate ratio increased, a higher binding signal was observed. The specificity and cytotoxicity of L-DOS47 was confirmed by screening in four cell lines (BxPC-3, A549, MCF7, and CEACAM6-transfected H23). BxPC-3, a CEACAM6-expressing cell line was found to be most susceptible to L-DOS47. L-DOS47 is being investigated as a potential therapeutic agent in human phase I clinical studies for nonsmall cell lung cancer.

High-throughput determination of urinary hexosamines for diagnosis of mucopolysaccharidoses by capillary electrophoresis and high-performance liquid chromatography.

PubMed

Coppa, Giovanni V; Galeotti, Fabio; Zampini, Lucia; Maccari, Francesca; Galeazzi, Tiziana; Padelia, Lucia; Santoro, Lucia; Gabrielli, Orazio; Volpi, Nicola

2011-04-01

Mucopolysaccharidoses (MPS) diagnosis is often delayed and irreversible organ damage can occur, making possible therapies less effective. This highlights the importance of early and accurate diagnosis. A high-throughput procedure for the simultaneous determination of glucosamine and galactosamine produced from urinary galactosaminoglycans and glucosaminoglycans by capillary electrophoresis (CE) and HPLC has been performed and validated in subjects affected by various MPS including their mild and severe forms, Hurler and Hurler-Scheie, Hunter, Sanfilippo, Morquio, and Maroteaux-Lamy. Contrary to other analytical approaches, the present single analytical procedure, which is able to measure total abnormal amounts of urinary GAGs, high molecular mass, and related fragments, as well as specific hexosamines belonging to a group of GAGs, would be useful for possible application in their early diagnosis. After a rapid urine pretreatment, free hexosamines are generated by acidic hydrolysis, derivatized with 2-aminobenzoic acid and separated by CE/UV in ∼10min and reverse-phase (RP)-HPLC in fluorescence in ∼21min. The total content of hexosamines was found to be indicative of abnormal urinary excretion of GAGs in patients compared to the controls, and the galactosamine/glucosamine ratio was observed to be related to specific MPS syndromes in regard to both their mild and severe forms. As a consequence, important correlations between analytical response and clinical diagnosis and the severity of the disorders were observed. Furthermore, we can assume that the severity of the syndrome may be ascribed to the quantity of total GAGs, as high-molecular-mass polymers and fragments, accumulated in cells and directly excreted in the urine. Finally, due to the high-throughput nature of this approach and to the equipment commonly available in laboratories, this method is suitable for newborn screening in preventive public health programs for early detection of MPS disorders, diagnosis, and their treatment. Copyright © 2010 Elsevier Inc. All rights reserved.

Novel hydroxyl radical scavenging antioxidant activity assay for water-soluble antioxidants using a modified CUPRAC method.

PubMed

Bektaşoğlu, Burcu; Esin Celik, Saliha; Ozyürek, Mustafa; Güçlü, Kubilay; Apak, Reşat

2006-07-07

Reactive oxygen species (ROS) such as superoxide anion, hydroxyl ((*)OH), peroxyl, and alkoxyl radicals may attack biological macromolecules giving rise to oxidative stress-originated diseases. Since (*)OH is very short-lived, secondary products resulting from (*)OH attack to various probes are measured. Although the measurement of aromatic hydroxylation with HPLC/electrochemical detection is more specific than the low-yield TBARS test, it requires sophisticated instrumentation. As a more convenient and less costly alternative, we used p-aminobenzoate, 2,4- and 3,5-dimethoxybenzoate probes for detecting hydroxyl radicals generated from an equivalent mixture of Fe(II)+EDTA with hydrogen peroxide. The produced hydroxyl radicals attacked both the probe and the water-soluble antioxidants in 37 degrees C-incubated solutions for 2h. The CUPRAC (i.e., our original method for total antioxidant capacity assay) absorbance of the ethylacetate extract due to the reduction of Cu(II)-neocuproine reagent by the hydroxylated probe decreased in the presence of (*)OH scavengers, the difference being proportional to the scavenging ability of the tested compound. A rate constant for the reaction of the scavenger with hydroxyl radical can be deduced from the inhibition of color formation. The second-order rate constants of the scavengers were determined with competition kinetics by means of a linear plot of A(0)/A as a function of C(scavenger)/C(probe), where A(0) and A are the CUPRAC absorbances of the system in the absence and presence of scavenger, respectively, and C is the molar concentration of relevant species. The 2,4- and 3,5-dimethoxybenzoates were the best probes in terms of linearity and sensitivity. Iodide, metabisulfite, hexacyanoferrate(II), thiourea, formate, and dimethyl sulfoxide were shown by the modified CUPRAC assay to be more effective scavengers than mannitol, glucose, lysine, and simple alcohols, as in the TBARS assay. The developed method is less lengthy, more specific, and of a higher yield than the classical TBARS assay. The hydroxyl radical scavenging rate constants of ascorbic acid, formate, and hexacyanoferrate(II) that caused interference in other assays could be easily found with the proposed procedure.

Water turnover in 458 American adults 40-79 yr of age.

PubMed

Raman, Aarthi; Schoeller, Dale A; Subar, Amy F; Troiano, Richard P; Schatzkin, Arthur; Harris, Tamara; Bauer, Douglas; Bingham, Shiela A; Everhart, James E; Newman, Anne B; Tylavsky, Frances A

2004-02-01

Despite recent interest in water intake, few data are available on water metabolism in adults. To determine the average and range of usual water intake, urine output, and total body water, we administered 2H oxide to 458 noninstitutionalized 40- to 79-yr-old adults living in temperate climates. Urine was collected in a subset of individuals (n = 280) to measure 24-h urine production using p-aminobenzoic acid to ensure complete collection. Preformed water intake was calculated from isotopic turnover and corrected for metabolic water and insensible water absorption from humidity. Preformed water intake, which is water from beverages and food moisture, averaged 3.0 l/day in men (range: 1.4-7.7 l/day) and 2.5 l/day in women (range: 1.2-4.6 l/day). Preformed water intake was lower in 70- to 79 (2.8 l/day)- than in 40- to 49-yr-old men and was lower in 70- to 79 (2.3 l/day)- than in 40- to 49- and 50- to 59-yr-old women. Urine production averaged 2.2 l/day in men (range: 0.6-4.9 l/day) and 2.2 l/day in women (0.9-6.0 l/day). There were no age-related differences in results in women, but 60- to 69-yr-old men had significantly higher urine output than 40- to 49- and 50- to 59-yr-old men. Only the 70- to 79-yr-old group included sufficient blacks for a racial analysis. Blacks in this age group showed significantly lower preformed water intake than did whites. Whites had significantly higher water turnover rates than blacks as well. Multivariate regression indicated that age, weight, height, and body mass index explained <12% of the gender-specific variance in water input or urine output, yet repeat measures indicated that within-individual coefficient of variation was 8% for preformed water intake (n = 22) and 9% for 24-h urine production (n = 222). These results demonstrate that water turnover is highly variable among individuals and that little of the variance is explained by anthropometric parameters.

A Titanium–Organic Framework as an Exemplar of Combining the Chemistry of Metal– and Covalent–Organic Frameworks

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

Nguyen, Ha L.; Gándara, Felipe; Furukawa, Hiroyasu

A crystalline material with a two-dimensional structure, termed metal–organic framework-901 (MOF-901), was prepared using a strategy that combines the chemistry of MOFs and covalent–organic frameworks (COFs). This strategy involves in situ generation of an amine-functionalized titanium oxo cluster, Ti6O6(OCH3)6(AB)6 (AB = 4-aminobenzoate), which was linked with benzene-1,4-dialdehyde using imine condensation reactions, typical of COFs. The crystal structure of MOF-901 is composed of hexagonal porous layers that are likely stacked in staggered conformation (hxl topology). This MOF represents the first example of combining metal cluster chemistry with dynamic organic covalent bond formation to give a new crystalline, extended framework of titaniummore » metal, which is rarely used in MOFs. The incorporation of Ti(IV) units made MOF-901 useful in the photocatalyzed polymerization of methyl methacrylate (MMA). The resulting polyMMA product was obtained with a high-number-average molar mass (26 850 g mol–1) and low polydispersity index (1.6), which in many respects are better than those achieved by the commercially available photocatalyst (P-25 TiO2). Additionally, the catalyst can be isolated, reused, and recycled with no loss in performance.« less

The investigation of the binding of 6-mercaptopurine to site I on human serum albumin.

PubMed

Sochacka, Jolanta; Baran, Wojciech

2012-12-01

6-Mercaptopurine (6-MP) is one of a large series of purine analogues which has been found active against human leukemias. The equilibrium dialysis, circular dichroism (CD) and molecular docking were employed to study the binding of 6-MP to human serum albumin (HSA). The binding of 6-MP to HSA in the equilibrium dialysis experiment was detected by measuring the displacement of 6-MP by specific markers for site I on HSA, warfarin (RWF), phenylbutazone (PhB) and n-butyl p-aminobenzoate (ABE). It was shown, according to CD data, that binding of 6-MP to HSA leads to alteration of HSA secondary structure. Based on the findings from displacement experiment and molecular docking simulation it was found that 6-MP was located within binding cavity of subdomain IIA and the space occupied by site markers overlapped with that of 6-MP. Displacement of 6-MP by the RWF or PhB was not up the level expected for a competitive mechanism, therefore displacement of 6-MP was rather by non-cooperative than that the direct competition. Instead, in case of the interaction between ABE and 6-MP, when the little enhancement of the binding of ABE by 6-MP was found, the interaction could be via a positively cooperative mechanism.

Endopeptidase-24.11 is the integral membrane peptidase initiating degradation of somatostatin in the hippocampus.

PubMed

Barnes, K; Doherty, S; Turner, A J

1995-04-01

The membrane metalloenzyme endopeptidase-24.11 has been localized by immunocytochemistry in the porcine hippocampus in the stratum oriens and stratum radiatum. Endopeptidase-24.11 was found to be approximately 10-fold more abundant in a striatal than a hippocampal membrane preparation. Both somatostatin-28 and somatostatin-14 were metabolized by endopeptidase-24.11, but the kinetics of hydrolysis markedly favoured the smaller form of the neuropeptide. After phase separation with Triton X-114 of striatal and hippocampal membrane preparations, and by using selective inhibitors, the major (> 80%) somatostatin-metabolizing activity was found to partition into the detergent-rich phase and was attributable predominantly to endopeptidase-24.11. The residual activity observed in the presence of the selective endopeptidase-24.11 inhibitor phosphoramidon was blocked by Pro-Ile or N-[1-(RS)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoate, inhibitors of endopeptidase-24.16 and endopeptidase-24.15, respectively. However, Pro-Ile, at comparable concentrations, was shown to inhibit endopeptidase-24.11, challenging the validity of its use as a selective inhibitor of endopeptidase-24.16. The immunocytochemical and Triton X-114 phase-separation data implicate endopeptidase-24.11, rather than endopeptidase-24.16 or endopeptidase-24.15, as the major physiological somatostatin-degrading neuropeptidase in the striatum and hippocampus.

Enhanced detection of myeloperoxidase activity in deep tissues through luminescent excitation of near-infrared nanoparticles.

PubMed

Zhang, Ning; Francis, Kevin P; Prakash, Arun; Ansaldi, Daniel

2013-04-01

A previous study reported the use of luminol for the detection of myeloperoxidase (MPO) activity using optical imaging in infiltrating neutrophils under inflammatory disease conditions. The detection is based on a photon-emitting reaction between luminol and an MPO metabolite. Because of tissue absorption and scattering, however, luminol-emitted blue light can be efficiently detected from superficial inflammatory foci only. In this study we report a chemiluminescence resonance energy transfer (CRET) methodology in which luminol-generated blue light excites nanoparticles to emit light in the near-infrared spectral range, resulting in remarkable improvement of MPO detectability in vivo. CRET caused a 37-fold increase in luminescence emission over luminol alone in detecting MPO activity in lung tissues after lipopolysaccharide challenge. We demonstrated a dependence of the chemiluminescent signal on MPO activity using MPO-deficient mice. In addition, co-administration of 4-aminobenzoic acid hydrazide (4-ABAH), an irreversible inhibitor of MPO, significantly attenuated luminescent emission from inflamed lungs. Inhibition of nitric oxide synthase with a nonspecific inhibitor, L-NAME, had no effect on luminol-mediated chemiluminescence production. Pretreatment of mice with MLN120B, a selective inhibitor of IKK-2, resulted in suppression of neutrophil infiltration to the lung tissues and reduction of MPO activity. We also demonstrated that CRET can effectively detect MPO activity at deep tissue tumor foci due to tumor development-associated neutrophil infiltration. We developed a sensitive MPO detection methodology that provides a means for visualizing and quantifying oxidative stress in deep tissue. This method is amenable to rapid evaluation of anti-inflammatory agents in animal models.

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

Colotelo, Alison HA; Smokorowski, Karen; Haxton, Tim

Current methods of fish epithelial injury detection are limited to gross macroscopic examination that has a subjective bias as well as an inability to reliably quantify the degree of injury. Fluorescein, a presumptive test for blood, has been shown to have the capability to detect and quantify fish epithelial injury. However, there are several other presumptive tests for blood (Bluestar*, phenolphthalein, and HemastixH) that may have benefits over the use of fluorescein, particularly for field research on wild fish. This study investigated the capabilities of these four tests to detect and quantify a variety of injuries commonly encountered by fishmore » (abrasion, cuts, fin frays, and punctures) using the freshwater bluegill Lepomis macrochirus as a model. Fluorescein was consistently found to be the most reliable (i.e., detected the highest proportion of true positive results and rarely detected false positive reactions) of the four presumptive tests for blood compared. Further testing was conducted to examine the reliability of fluorescein. By 24 h after an injury was inflicted, the injury was no longer detectable by fluorescein, and when fluorescein was applied to an injured fish, the fluorescein was no longer detectable 3 h after application. In a comparison of two common anaesthetics used in fisheries research, there was no significant difference in the proportion of injury detected when 3- aminobenzoic acid ethyl ester methanesulfate (tricaine) was used compared with a clove oil and ethanol (1:9) solution. In summary, fluorescein was the most reliable presumptive test for blood examined in this study for the detection and quantification of recent (hours) fish epithelial injury.« less

Cyclometalation and coupling of a rigid 4,5-bis(imino)acridanide pincer ligand on yttrium.

PubMed

Wong, Edwin W Y; Emslie, David J H

2015-07-07

An extremely rigid NNN-donor proligand, 4,5-bis{(diphenylmethylene)amino}-2,7,9,9-tetramethylacridan, H[AIm2] was prepared in five steps starting from 5-methyl-2-aminobenzoic acid and 4-bromotoluene. Reaction of intensely orange H[AIm2] with LiCH2SiMe3 formed deep blue Li(x)[AIm2]x (x = 2 in the solid state), while reaction with [Y(CH2SiMe3)3(THF)2] (0.5 equiv.) afforded deep blue [Y(AIm2)(AIm)] (1; AIm = an AIm2 ligand cyclometalated at the ortho-position of one of the phenyl rings). Compound 1 slowly isomerizes to form green-brown 2, which contains a single trianionic, hexadentate ligand that features one amine, two imine, and three amido donors. The acridanide backbone and one imine group in each of the original AIm2 ligands is intact, but the two acridanide backbones are now linked by an isoindoline heterocycle. Yttrium in 2 is coordinated to six nitrogen donors and the ortho carbon of an isoindoline phenyl substituent. The intense colours of H[AIm2], Li(x)[AIm2]x and 1 were shown by TD-DFT calculations to arise from charge transfer transitions from the HOMO, which is localized on the acridanide ligand backbone, to the LUMO and LUMO+1, which are localized on the imine substituents. The conversion of 1 to 2 was studied by UV-Visible absorption spectroscopy and is first-order with a half-life of 7.8 hours at room temperature.

Analytical characterization of ch14.18: a mouse-human chimeric disialoganglioside-specific therapeutic antibody.

PubMed

Soman, Gopalan; Kallarakal, Abraham T; Michiel, Dennis; Yang, Xiaoyi; Saptharish, Nirmala; Jiang, Hengguang; Giardina, Steve; Gilly, John; Mitra, George

2012-01-01

Ch14.18 is a mouse-human chimeric monoclonal antibody to the disialoganglioside (GD2) glycolipid. In the clinic, this antibody has been shown to be effective in the treatment of children with high-risk neuroblastoma, either alone or in combination therapy. Extensive product characterization is a prerequisite to addressing the potential issues of product variability associated with process changes and manufacturing scale-up. Charge heterogeneity, glycosylation profile, molecular state and aggregation, interaction (affinity) with Fcγ receptors and functional or biological activities are a few of the critical characterization assays for assessing product comparability for this antibody. In this article, we describe the in-house development and qualification of imaged capillary isoelectric focusing to assess charge heterogeneity, analytical size exclusion chromatography with online static and dynamic light scattering (DLS), batch mode DLS for aggregate detection, biosensor (surface plasmon resonance)-based Fcγ receptor antibody interaction kinetics, N-glycoprofiling with PNGase F digestion, 2-aminobenzoic acid labeling and high performance liquid chromatography and N-glycan analysis using capillary electrophoresis. In addition, we studied selected biological activity assays, such as complement-dependent cytotoxicity. The consistency and reproducibility of the assays are established by comparing the intra-day and inter-day assay results. Applications of the methodologies to address stability or changes in product characteristics are also reported. The study results reveal that the ch14.18 clinical product formulated in phosphate-buffered saline at a concentration of 5 mg/ml and stored at 2-8°C is stable for more than five years.

Socio-demographic characteristics and risk factors among HIV/AIDS patients in Kano, Northern Nigeria.

PubMed

Iliyasu, Z; Arotiba, J T; Babashani, M

2004-01-01

There has been no description of the characteristics of HIV/AIDS patients that are referred to this antiretroviral treatment centre. The information could be useful in planning for prevention, care and support of people living with HIV/AIDS (PLWHA) and people affected by AIDS (PABA). To describe the socio-demographic characteristics and identify risk factors among HIV/AIDS patients presenting to Aminu Kano Teaching Hospital. Analysis of a prospectively collected data on 205 consecutive patients presenting to Aminu Kano Teaching Hospital from May 2002 to June 2003. Out of the 205 HIV positive patients seen, there were 112 (54.6%) males and 93 (45.4%) females giving a sex ratio of 1.2:1. The age range was 18 to 61 years with an overall mean S.D of 33.7 +/- [corrected] 8 years. The mean for males was 37.3 +/- [corrected] 7.8 years compared to 29.56 years for females. This difference was statistically significant (t = 8.1 DF = 201 P < 0.001). About 38.5% of the patients had secondary school education, 36.1% had tertiary education and 10.2% had primary education. Half of the patients were Hausas, 18.5% Igbos, 4.9% Idomas and 3.4% Igalas. Sixty percent were Muslims, the rest were Christians. About 64.0% were married, 23.0% were single and 11.0 % were divorced. Only 17.0% reported having multiple sexual partners. Eighteen percent claimed they use condoms always, 67.8% occasionally and 8.3% never. Twenty percent of the patients had previous blood transfusion. None reported intravenous drug abuse or homosexuality. The need for a sustained multi-sectoral preventive effort and the scaling up of treatment and community care initiatives were stressed.

Identification of Transport-critical Residues in a Folate Transporter from the Folate-Biopterin Transporter (FBT) Family*

PubMed Central

Eudes, Aymerick; Kunji, Edmund R. S.; Noiriel, Alexandre; Klaus, Sebastian M. J.; Vickers, Tim J.; Beverley, Stephen M.; Gregory, Jesse F.; Hanson, Andrew D.

2010-01-01

The Synechocystis Slr0642 protein and its plastidial Arabidopsis (Arabidopsis thaliana) ortholog At2g32040 belong to the folate-biopterin transporter (FBT) family within the major facilitator superfamily. Both proteins transport folates when expressed in Escherichia coli. Because the structural requirements for transport activity are not known for any FBT protein, we applied mutational analysis to identify residues that are critical to transport and interpreted the results using a comparative structural model based on E. coli lactose permease. Folate transport was assessed via the growth of an E. coli pabA abgT strain, which cannot synthesize or take up folates or p-aminobenzoylglutamate. In total, 47 residues were replaced with Cys or Ala. Mutations at 22 positions abolished folate uptake without affecting Slr0642 expression in membranes, whereas other mutations had no effect. Residues important for function mostly line the predicted central cavity and are concentrated in the core α-helices H1, H4, H7, and H10. The essential residue locations are consistent with a folate-binding site lying roughly equidistant from both faces of the transporter. Arabidopsis has eight FBT proteins besides At2g32040, often lacking conserved critical residues. When six of these proteins were expressed in E. coli or in Leishmania folate or pterin transporter mutants, none showed evidence of folate or pterin transport activity, and only At2g32040 was isolated by functional screening of Arabidopsis cDNA libraries in E. coli. Such negative data could reflect roles in transport of other substrates. These studies provide the first insights into the native structure and catalytic mechanism of FBT family carriers. PMID:19923217

Phenolic Acid Composition, Antiatherogenic and Anticancer Potential of Honeys Derived from Various Regions in Greece

PubMed Central

Spilioti, Eliana; Jaakkola, Mari; Tolonen, Tiina; Lipponen, Maija; Virtanen, Vesa; Chinou, Ioanna; Kassi, Eva; Karabournioti, Sofia; Moutsatsou, Paraskevi

2014-01-01

The phenolic acid profile of honey depends greatly on its botanical and geographical origin. In this study, we carried out a quantitative analysis of phenolic acids in the ethyl acetate extract of 12 honeys collected from various regions in Greece. Our findings indicate that protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid and p-coumaric acid are the major phenolic acids of the honeys examined. Conifer tree honey (from pine and fir) contained significantly higher concentrations of protocatechuic and caffeic acid (mean: 6640 and 397 µg/kg honey respectively) than thyme and citrus honey (mean of protocatechuic and caffeic acid: 437.6 and 116 µg/kg honey respectively). p-Hydroxybenzoic acid was the dominant compound in thyme honeys (mean: 1252.5 µg/kg honey). We further examined the antioxidant potential (ORAC assay) of the extracts, their ability to influence viability of prostate cancer (PC-3) and breast cancer (MCF-7) cells as well as their lowering effect on TNF- α-induced adhesion molecule expression in endothelial cells (HAEC). ORAC values of Greek honeys ranged from 415 to 2129 µmol Trolox equivalent/kg honey and correlated significantly with their content in protocatechuic acid (p<0.001), p-hydroxybenzoic acid (p<0.01), vanillic acid (p<0.05), caffeic acid (p<0.01), p-coumaric acid (p<0.001) and their total phenolic content (p<0.001). Honey extracts reduced significantly the viability of PC-3 and MCF-7 cells as well as the expression of adhesion molecules in HAEC. Importantly, vanillic acid content correlated significantly with anticancer activity in PC-3 and MCF-7 cells (p<0.01, p<0.05 respectively). Protocatechuic acid, vanillic acid and total phenolic content correlated significantly with the inhibition of VCAM-1 expression (p<0.05, p<0.05 and p<0.01 respectively). In conclusion, Greek honeys are rich in phenolic acids, in particular protocatechuic and p-hydroxybenzoic acid and exhibit significant antioxidant, anticancer and antiatherogenic activities which may be attributed, at least in part, to their phenolic acid content. PMID:24752205

Acid Rain, pH & Acidity: A Common Misinterpretation.

ERIC Educational Resources Information Center

Clark, David B.; Thompson, Ronald E.

1989-01-01

Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

Relationship between Acute Phase Proteins and Serum Fatty Acid Composition in Morbidly Obese Patients

PubMed Central

Fernandes, Ricardo; Beserra, Bruna Teles Soares; Cunha, Raphael Salles Granato; Hillesheim, Elaine; Camargo, Carolina de Quadros; Pequito, Danielle Cristina Tonello; de Castro, Isabela Coelho; Fernandes, Luiz Cláudio; Nunes, Everson Araújo; Trindade, Erasmo Benício Santos de Moraes

2013-01-01

Background. Obesity is considered a low-grade inflammatory state and has been associated with increased acute phase proteins as well as changes in serum fatty acids. Few studies have assessed associations between acute phase proteins and serum fatty acids in morbidly obese patients. Objective. To investigate the relationship between acute phase proteins (C-Reactive Protein, Orosomucoid, and Albumin) and serum fatty acids in morbidly obese patients. Methods. Twenty-two morbidly obese patients were enrolled in this study. Biochemical and clinical data were obtained before bariatric surgery, and fatty acids measured in preoperative serum. Results. Orosomucoid was negatively correlated with lauric acid (P = 0.027) and eicosapentaenoic acid (EPA) (P = 0.037) and positively with arachidonic acid (AA) (P = 0.035), AA/EPA ratio (P = 0.005), and n-6/n-3 polyunsaturated fatty acids ratio (P = 0.035). C-Reactive Protein (CRP) was negatively correlated with lauric acid (P = 0.048), and both CRP and CRP/Albumin ratio were negatively correlated with margaric acid (P = 0.010, P = 0.008, resp.). Albumin was positively correlated with EPA (P = 0.027) and margaric acid (P = 0.008). Other correlations were not statistically significant. Conclusion. Our findings suggest that serum fatty acids are linked to acute phase proteins in morbidly obese patients. PMID:24167354

Effects of three kinds of organic acids on phosphorus recovery by magnesium ammonium phosphate (MAP) crystallization from synthetic swine wastewater.

PubMed

Song, Yonghui; Dai, Yunrong; Hu, Qiong; Yu, Xiaohua; Qian, Feng

2014-04-01

P recovery from swine wastewater has become a great concern as a result of the high demand for P resources and its potential eutrophication effects on water ecosystems. The method of magnesium ammonium phosphate (MAP) crystallization was used to recover P from simulated swine wastewater, and the effects of three organic acids (citric acid, succinic acid and acetic acid) on P removal efficiency and rate at different pH values were investigated. The results indicated that the P removal efficiency was worst affected by citric acid in the optimal pH range of 9.0-10.5, followed by succinic acid and acetic acid, and the influencing extent of organic acids decreased with the increasing pH value. Due to the complexation between organic acid and Mg(2+)/NH4(+), all of three organic acids could inhibit the P removal rate at the beginning of the reaction, which showed positive correlation between the inhibition effects and the concentration of organic acids. The high concentration of citric acid could completely suppress the MAP crystallization reaction. Moreover, citric acid and succinic acid brought obvious effects on the morphology of the crystallized products. The experimental results also demonstrated that MAP crystals could be obtained in the presence of different kinds and concentrations of organic acids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Phenolic acids in the flowers of Althaea rosea var. nigra.

PubMed

Dudek, Marlena; Matławska, Irena; Szkudlarek, Maurycy

2006-01-01

Distribution of phenolic acids in the flowers of Althaea rosea var. nigra has been studied by 2D-TLC and HPLC methods. The phenolic acids occurring in these fractions have been identified as ferulic, vanillic, syringic, p-coumaric, p-hydroxybenzoic, p-hydroxyphenylacetic and caffeic acids. By means of the HPLC methods the contents of major phenolic acids were estimated. From among the phenolic acids analyzed the syringic, p-hydroxybenzoic and p-coumaric acids are dominant. Total content of phenolic acids was determined by the Arnov's method.

Acidity and Alkalinity in mine drainage: Practical considerations

USGS Publications Warehouse

Cravotta, III, Charles A.; Kirby, Carl S.

2004-01-01

In this paper, we emphasize that the Standard Method hot peroxide treatment procedure for acidity determination (hot acidity) directly measures net acidity or net alkalinity, but that more than one water-quality measure can be useful as a measure of the severity of acid mine drainage. We demonstrate that the hot acidity is related to the pH, alkalinity, and dissolved concentrations of Fe, Mn, and Al in fresh mine drainage. We show that the hot acidity accurately indicates the potential for pH to decrease to acidic values after complete oxidation of Fe and Mn, and it indicates the excess alkalinity or that required for neutralization of the sample. We show that the hot acidity method gives consistent, interpretable results on fresh or aged samples. Regional data for mine-drainage quality in Pennsylvania indicated the pH of fresh samples was predominantly acidic (pH 2.5 to 4) or near neutral (pH 6 to 7); approximately 25 percent of the samples had intermediate pH values. This bimodal frequency distribution of pH was distinctive for fully oxidized samples; oxidized samples had acidic or near-neutral pH, only. Samples that had nearneutral pH after oxidation had negative hot acidity; samples that had acidic pH after oxidation had positive hot acidity. Samples with comparable pH values had variable hot acidities owing to variations in their alkalinities and dissolved Fe, Mn, and Al concentrations. The hot acidity was comparable to net acidity computed on the basis of initial pH and concentrations of Fe, Mn, and Al minus the initial alkalinity. Acidity computed from the pH and dissolved metals concentrations, assuming equivalents of 2 per mole of Fe and Mn and 3 per mole of Al, was comparable to that computed on the basis of aqueous species and FeII/FeIII. Despite changes in the pH, alkalinity, and metals concentrations, the hot acidities were comparable for fresh and aged samples. Thus, meaningful “net” acidity can be determined from a measured hot acidity or by calculation from the pH, alkalinity, and dissolved metals concentrations. Together, these water-quality data can be useful for evaluating the potential for toxicity, corrosion, or encrustation and can be helpful for determining the appropriate remediation. By demonstrating the measurements on fresh and aged samples, we hope to encourage (1) consistent use of the hot peroxide treatment procedure for acidity determination and (2) consistent reporting of negative acidity values.

Single-crystal diffuse scattering studies on polymorphs of molecular crystals. I. The room-temperature polymorphs of the drug benzocaine.

PubMed

Chan, E J; Welberry, T R; Goossens, D J; Heerdegen, A P; Beasley, A G; Chupas, P J

2009-06-01

The drug benzocaine (ethyl 4-aminobenzoate), commonly used as a local anaesthetic, is a bimorphic solid at room temperature. Form (I) is monoclinic P2(1)/c, while the metastable form (II) is orthorhombic P2(1)2(1)2(1). Three-dimensional diffuse X-ray scattering data have been collected for the two forms on the 11-ID-B beamline at the Advanced Photon Source (APS). Both forms show strong and highly structured diffuse scattering. The data have been interpreted and analysed using Monte Carlo (MC) modelling on the basis that the scattering is purely thermal in origin and indicates the presence of highly correlated molecular motions. In both forms (I) and (II) broad diffuse streaks are observed in the 0kl section which indicate strong longitudinal displacement correlations between molecules in the 031 directions, extending over distances of up to 50 A. Streaks extending between Bragg peaks in the hk0 section normal to [100] correspond to correlated motions of chains of molecules extending along a that are linked by N-H...O=C hydrogen bonds and which occur together as coplanar ribbon pairs. The main difference between the two forms is in the dynamical behaviour of the ribbon pairs and in particular how they are able to slide relative to each other. While for form (I) a model involving harmonic springs is able to describe the motion satisfactorily, as simple excursions away from the average structure, there is evidence in form (II) of anharmonic effects that are precursors of a phase transition to a new low-temperature phase, form (III), that was subsequently found.

Electroactive crown ester-Cu2+ complex with in-situ modification at molecular beacon probe serving as a facile electrochemical DNA biosensor for the detection of CaMV 35s.

PubMed

Zhan, Fengping; Liao, Xiaolei; Gao, Feng; Qiu, Weiwei; Wang, Qingxiang

2017-06-15

A novel electrochemical DNA biosensor has been facilely constructed by in-situ assembly of electroactive 4'-aminobenzo-18-crown-6-copper(II) complex (AbC-Cu 2+ ) on the free terminal of the hairpin-structured molecule beacon. The 3'-SH modified molecule beacon probe was first immobilized on the gold electrode (AuE) surface through self-assembly chemistry of Au-S bond. Then the crow ester of AbC was covalently coupled with 5'-COOH on the molecule beacon, and served as a platform to attach the Cu 2+ by coordination with ether bond (-O-) of the crown cycle. Thus, an electroactive molecule beacon-based biosensing interface was constructed. In comparison with conventional methods for preparation of electroactive molecule beacon, the approach presented in this work is much simpler, reagent- and labor-saving. Selectivity study shows that the in-situ fabricated electroactive molecule beacon remains excellent recognition ability of pristine molecule beacon probe to well differentiate various DNA fragments. The target DNA can be quantatively determined over the range from 0.10pM to 0.50nM. The detection limit of 0.060pM was estimated based on signal-to-noise ratio of 3. When the biosensor was applied for the detection cauliflower mosaic virus 35s (CaMV 35s) in soybean extraction samples, satisfactory results are achieved. This work opens a new strategy for facilely fabricating electrochemical sensing interface, which also shows great potential in aptasensor and immurosensor fabrication. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting under...

40 CFR 721.10135 - Phosphinic acid, P,P-diethyl-, zinc salt (2:1).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphinic acid, P,P-diethyl-, zinc... Specific Chemical Substances § 721.10135 Phosphinic acid, P,P-diethyl-, zinc salt (2:1). (a) Chemical... acid, P,P-diethyl-, zinc salt (2:1) (PMN P-05-11; CAS No. 284685-45-6) is subject to reporting under...

Differential Effects of Methoxylated p-Coumaric Acids on Melanoma in B16/F10 Cells

PubMed Central

Yoon, Hoon Seok; Lee, Nam-Ho; Hyun, Chang-Gu; Shin, Dong-Bum

2015-01-01

As an approach to search for chemopreventive agents, we tested p-coumaric acid, 3-methoxy-p-coumaric acid (ferulic acid), and 3,5-dimethoxy-p-coumaric acid (sinapic acid) in B16/F10 melanoma cells. Intracellular melanin contents were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and cytotoxicity of the compounds were examined by lactate dehydrogenase (LDH) release. p-Coumaric acid showed inhibitory effect on melanogenesis, but ferulic acid increased melanin content, and sinapic acid had almost no effect on melanogenesis. Treatment with ferulic acid resulted in a 2 to 3 fold elevation in the production of melanin. Correlatively, cell viability decreased in a dose-dependent manner when treated with ferulic acid. However, ferulic acid did not affect the LDH release from the cells. Treatment with sinapic acid resulted in a 50~60% elevation in the release of LDH when treated with a 200 μg/mL concentration and showed neither cytostasis nor increase of melanin synthesis in a dose-dependent manner. Taken together, p-coumaric acid inhibits melanogenesis, ferulic acid induces melanogenesis, and sinapic acid exerts cytotoxic effects in B16/F10 murine melanoma cells. The results indicate that the addition of methoxy groups to p-coumaric acid shows the melanogenic or cytotoxic effects in melanoma cells compared to the original compound. Therefore, this study suggests the possibility that methoxylated p-coumaric acid, ferulic acid can be used as a chemopreventive agent. PMID:25866753

Avocado and soybean extracts as active principles in the treatment of mild-to-moderate vulvar lichen sclerosus: results of efficacy and tolerability.

PubMed

Borghi, A; Corazza, M; Minghetti, S; Toni, G; Virgili, A

2015-06-01

Limited evidence is available on the effectiveness of treatments alternative to corticosteroids for vulvar lichen sclerosus (VLS). The present study aimed to assess the efficacy and tolerability of avocado and soybean extracts (ASE) as active principles of both a topical product and a nutritional supplement in the treatment of active mild-to-moderate VLS. Twenty-three patients were enrolled. Treatment consisted of a topical product containing ASE and other lenitive and anti-oxidant principles administered twice daily for 24 weeks, in association with a dietary supplement containing ASE, vitamin E and para-aminobenzoic acid for the first 12 weeks. The primary efficacy endpoint was the rate of patients achieving an improvement from baseline in global subjective score (GSS) and global objective score (GOS) of ≥ 75%. Secondary efficacy endpoint was the rate of patients achieving GSS50 and GOS50. Tertiary efficacy endpoint was the mean reduction in subjective and objective scores throughout the treatment. By the end of the 24-week treatment, 12 (70.5% of symptomatic patients) and 13 patients (72.2%) achieved an improvement of at least 75% in subjective and objective global scores, respectively; 100% and 88.9% reached GSS50 and GOS50, respectively. Mean symptom and sign scores decreased significantly after treatment. The treatment was well tolerated. Our results provide evidence that the topical and dietary supplements used in the study, which contain active principles exerting anti-inflammatory, anti-fibrotic, emollient and lenitive actions, are effective alternatives in the treatment of symptoms and signs of mild-to-moderate VLS. © 2014 European Academy of Dermatology and Venereology.

Validation of a thin-layer chromatography/densitometry method for the characterization of invertase activity.

PubMed

Ferey, Justine; Da Silva, David; Bravo-Veyrat, Sophie; Lafite, Pierre; Daniellou, Richard; Maunit, Benoît

2016-12-16

This paper presents a kinetic study of invertase, a specific fructofuranosidase cloned from the Leishmania major genome. The kinetic parameters of the β-d-fructofuranosidase from Leishmania major (BfrA) were determined using Thin-Layer Chromatography (TLC) and UV-densitometry (TLC@UV) specifically developed for the separation and detection of three carbohydrates namely sucrose, glucose and fructose. Separation was performed on TLC silica gel 60 F254 plates impregnated with sodium bisulphate and citrate and heated prior to development. This fast and easy separation was performed with two successive developments using ACN/H 2 O 80/20 (v/v) as mobile phase. Sensitive and repeatable derivatization of sugars was achieved by dipping the plates in a solution of 4-aminobenzoic acid. Quantification was performed by UV-detection. The method was validated according to ICH guidelines Q2(R1) in terms of specificity, limits of detection and quantification, precision and robustness (with n=3 replicates and CV ≤10%). The characterization of BfrA reaction kinetic was performed by monitoring the accumulation of either glucose or fructose detected by TLC@UV. Hydrolysis of sucrose was described by the Michaelis-Menten kinetic parameters (K M ; V max ) respectively equal to 63.09±7.590mM; 0.037±0.00094mM/min using glucose production and 83.01±14.39mM; 0.031±0.0021mM/min monitoring fructose. Hydrolyses of three alternative substrates, raffinose, stachyose and inulin, were also compared and the regiospecificity of the reaction was characterized. This TLC@UV method is shown to be suitable for the refined kinetic analysis of different reactions related to the hydrolysis of sugars. Copyright © 2016. Published by Elsevier B.V.

Evidence for an imidazoline by-product from glycans using tandem mass spectrometry.

PubMed

Duff, Robert J; Smith, Elaine; Li, Wenzhou; Fodor, Szilan

2017-06-09

Herein is reported the separation and identification of a previously unknown imidazoline by-product originating from the fluorescent labeling procedure when applied to enzymatically released N-linked glycans of a human IgG1. The imidazoline by-product was generated via the reductive amination procedure with either sodium cyanoborohydride or 2-picoline borane. Using ultra performance liquid chromatography (UPLC) in conjunction with hydrophilic interaction-based chromatography (HILIC), the 2-aminobenzoic acid (2-AA)-labeled glycans were well-resolved from imidazoline by-products to facilitate direct identification utilizing electrospray ionization mass spectrometry (ESI-MS) with fragmentation. It was found that this minor species (∼2%) was 18.0105u less than the neighboring peak GlcNAc 2 Man 3 GlcNAc 2 Fuc peak, abbreviated as A2G0F at 1582.5899u. While this mass loss corresponds to the mass of a water molecule, the molecular location of loss of water was not straightforward in consideration of the biantennary A2G0F structure. Model studies were carried out using A2G0F standard and N-acetyllactosamine to identify the impurity as an imidazoline ring structure located at the reducing end of the glycan as confirmed by high resolution mass fragment ions. Imidazoline content decreased when the reductant concentration was increased. To conclude, evidence for the imidazoline structure was accomplished through high resolution, high accuracy mass spectrometry (HRAM), and experiments showing chemical susceptibility and isotopically labeled tracers. This study is the first to identify these minor species which likely impact all N-acetylglucosamine-type N-linked glycans from biologics. Copyright © 2017 Elsevier B.V. All rights reserved.

A multi-method approach toward de novo glycan characterization: a Man-5 case study.

PubMed

Prien, Justin M; Prater, Bradley D; Cockrill, Steven L

2010-05-01

Regulatory agencies' expectations for biotherapeutic approval are becoming more stringent with regard to product characterization, where minor species as low as 0.1% of a given profile are typically identified. The mission of this manuscript is to demonstrate a multi-method approach toward de novo glycan characterization and quantitation, including minor species at or approaching the 0.1% benchmark. Recently, unexpected isomers of the Man(5)GlcNAc(2) (M(5)) were reported (Prien JM, Ashline DJ, Lapadula AJ, Zhang H, Reinhold VN. 2009. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap mass spectrometry (MS). J Am Soc Mass Spectrom. 20:539-556). In the current study, quantitative analysis of these isomers found in commercial M(5) standard demonstrated that they are in low abundance (<1% of the total) and therefore an exemplary "litmus test" for minor species characterization. A simple workflow devised around three core well-established analytical procedures: (1) fluorescence derivatization; (2) online rapid resolution reversed-phase separation coupled with negative-mode sequential mass spectrometry (RRRP-(-)-MS(n)); and (3) permethylation derivatization with nanospray sequential mass spectrometry (NSI-MS(n)) provides comprehensive glycan structural determination. All methods have limitations; however, a multi-method workflow is an at-line stopgap/solution which mitigates each method's individual shortcoming(s) providing greater opportunity for more comprehensive characterization. This manuscript is the first to demonstrate quantitative chromatographic separation of the M(5) isomers and the use of a commercially available stable isotope variant of 2-aminobenzoic acid to detect and chromatographically resolve multiple M(5) isomers in bovine ribonuclease B. With this multi-method approach, we have the capabilities to comprehensively characterize a biotherapeutic's glycan array in a de novo manner, including structural isomers at >/=0.1% of the total chromatographic peak area.

Development of a Schistosoma mansoni shotgun O-glycan microarray and application to the discovery of new antigenic schistosome glycan motifs.

PubMed

van Diepen, Angela; van der Plas, Arend-Jan; Kozak, Radoslaw P; Royle, Louise; Dunne, David W; Hokke, Cornelis H

2015-06-01

Upon infection with Schistosoma, antibody responses are mounted that are largely directed against glycans. Over the last few years significant progress has been made in characterising the antigenic properties of N-glycans of Schistosoma mansoni. Despite also being abundantly expressed by schistosomes, much less is understood about O-glycans and antibody responses to these have not yet been systematically analysed. Antibody binding to schistosome glycans can be analysed efficiently and quantitatively using glycan microarrays, but O-glycan array construction and exploration is lagging behind because no universal O-glycanase is available, and release of O-glycans has been dependent on chemical methods. Recently, a modified hydrazinolysis method has been developed that allows the release of O-glycans with free reducing termini and limited degradation, and we applied this method to obtain O-glycans from different S. mansoni life stages. Two-dimensional HPLC separation of 2-aminobenzoic acid-labelled O-glycans generated 362 O-glycan-containing fractions that were printed on an epoxide-modified glass slide, thereby generating the first shotgun O-glycan microarray containing naturally occurring schistosome O-glycans. Monoclonal antibodies and mass spectrometry showed that the O-glycan microarray contains well-known antigenic glycan motifs as well as numerous other, potentially novel, antibody targets. Incubations of the microarrays with sera from Schistosoma-infected humans showed substantial antibody responses to O-glycans in addition to those observed to the previously investigated N- and glycosphingolipid glycans. This underlines the importance of the inclusion of these often schistosome-specific O-glycans in glycan antigen studies and indicates that O-glycans contain novel antigenic motifs that have potential for use in diagnostic methods and studies aiming at the discovery of vaccine targets. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

N-glycosylation of colorectal cancer tissues: a liquid chromatography and mass spectrometry-based investigation.

PubMed

Balog, Crina I A; Stavenhagen, Kathrin; Fung, Wesley L J; Koeleman, Carolien A; McDonnell, Liam A; Verhoeven, Aswin; Mesker, Wilma E; Tollenaar, Rob A E M; Deelder, André M; Wuhrer, Manfred

2012-09-01

Colorectal cancer is the third most common cancer worldwide with an annual incidence of ~1 million cases and an annual mortality rate of ~655,000 individuals. There is an urgent need for identifying novel targets to develop more sensitive, reliable, and specific tests for early stage detection of colon cancer. Post-translational modifications are known to play an important role in cancer progression and immune surveillance of tumors. In the present study, we compared the N-glycan profiles from 13 colorectal cancer tumor tissues and corresponding control colon tissues. The N-glycans were enzymatically released, purified, and labeled with 2-aminobenzoic acid. Aliquots were profiled by hydrophilic interaction liquid chromatography (HILIC-HPLC) with fluorescence detection and by negative mode MALDI-TOF-MS. Using partial least squares discriminant analysis to investigate the N-glycosylation changes in colorectal cancer, an excellent separation and prediction ability were observed for both HILIC-HPLC and MALDI-TOF-MS data. For structure elucidation, information from positive mode ESI-ion trap-MS/MS and negative mode MALDI-TOF/TOF-MS was combined. Among the features with a high separation power, structures containing a bisecting GlcNAc were found to be decreased in the tumor, whereas sulfated glycans, paucimannosidic glycans, and glycans containing a sialylated Lewis type epitope were shown to be increased in tumor tissues. In addition, core-fucosylated high mannose N-glycans were detected in tumor samples. In conclusion, the combination of HILIC and MALDI-TOF-MS profiling of N-glycans with multivariate statistical analysis demonstrated its potential for identifying N-glycosylation changes in colorectal cancer tissues and provided new leads that might be used as candidate biomarkers.

N-glycosylation of Colorectal Cancer Tissues

PubMed Central

Balog, Crina I. A.; Stavenhagen, Kathrin; Fung, Wesley L. J.; Koeleman, Carolien A.; McDonnell, Liam A.; Verhoeven, Aswin; Mesker, Wilma E.; Tollenaar, Rob A. E. M.; Deelder, André M.; Wuhrer, Manfred

2012-01-01

Colorectal cancer is the third most common cancer worldwide with an annual incidence of ∼1 million cases and an annual mortality rate of ∼655,000 individuals. There is an urgent need for identifying novel targets to develop more sensitive, reliable, and specific tests for early stage detection of colon cancer. Post-translational modifications are known to play an important role in cancer progression and immune surveillance of tumors. In the present study, we compared the N-glycan profiles from 13 colorectal cancer tumor tissues and corresponding control colon tissues. The N-glycans were enzymatically released, purified, and labeled with 2-aminobenzoic acid. Aliquots were profiled by hydrophilic interaction liquid chromatography (HILIC-HPLC) with fluorescence detection and by negative mode MALDI-TOF-MS. Using partial least squares discriminant analysis to investigate the N-glycosylation changes in colorectal cancer, an excellent separation and prediction ability were observed for both HILIC-HPLC and MALDI-TOF-MS data. For structure elucidation, information from positive mode ESI-ion trap-MS/MS and negative mode MALDI-TOF/TOF-MS was combined. Among the features with a high separation power, structures containing a bisecting GlcNAc were found to be decreased in the tumor, whereas sulfated glycans, paucimannosidic glycans, and glycans containing a sialylated Lewis type epitope were shown to be increased in tumor tissues. In addition, core-fucosylated high mannose N-glycans were detected in tumor samples. In conclusion, the combination of HILIC and MALDI-TOF-MS profiling of N-glycans with multivariate statistical analysis demonstrated its potential for identifying N-glycosylation changes in colorectal cancer tissues and provided new leads that might be used as candidate biomarkers. PMID:22573871

Characterization, liquid crystalline behavior, electrochemical and optoelectrical properties of new poly(azomethine)s and a poly(imide) with siloxane linkages

NASA Astrophysics Data System (ADS)

Iwan, Agnieszka; Schab-Balcerzak, Ewa; Pociecha, Damian; Krompiec, Michal; Grucela, Marzena; Bilski, Pawel; Kłosowski, Mariusz; Janeczek, Henryk

2011-11-01

New siloxane-containing poly(azomethine)s and a six-membered poly(imide) have been developed from siloxane-containing diamine with four different dialdehydes and 3,4,9,10-perylenetetracarboxylic dianhydride, and their thermotropic behavior, optoelectrical and electrochemical properties were examined. Mesomorphic behavior of the polymers was investigated via differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXRD, SAXRD) studies. The electrochemical behavior of poly(azomethine)s and poly(imide) was studied by differential pulse voltammetry (DPV). The HOMO levels of these polymers were in the range of -5.13 to -5.90 eV. UV-vis properties of the polymers were investigated in solid state as thin films and in chloroform solution. Optical energy band gap ( Egopt.) was calculated from absorption spectra and absorption coefficients α. The photoluminescence properties (PL) of obtained polymers were studied in chloroform solution. The investigated poly(azomethine)s emitted blue light, while the poly(imide) emitted green light. The polymers were irradiated with a test dose of 1 Gy Co-60 gamma-rays to detect their thermoluminescence properties in the temperature range of 50-200 °C. Polymer monolayer (ITO/polymer/Al) and bulk heterojunction (BHJ) (ITO/polymer:PCBM/Al and ITO/PEDOT:PSS/polymer:PCBM/Al) devices were prepared with PAZ and PI used as active layers and I- U curves were measured in the dark and during irradiation with light (under illumination of 1000 W/m 2). Poly(azomethine)s were blended with [6,6]-phenyl C 61 butyric acid methyl ester (PCBM). Selected properties of the investigated polymers with siloxane linkages were compared with the polymers ( PAZ1a- PAZ3a, PIa) prepared from the same dialdehydes or dianhydride and poly(1,4-butanediol)bis(4-aminobenzoate).

Grape skins (Vitis vinifera L.) catalyze the in vitro enzymatic hydroxylation of p-coumaric acid to caffeic acid.

PubMed

Arnous, Anis; Meyer, Anne S

2009-12-01

The ability of grape skins to catalyze in vitro conversion of p-coumaric acid to the more potent antioxidant caffeic acid was studied. Addition of different concentrations of p-coumaric to red grape skins (Cabernet Sauvignon) resulted in formation of caffeic acid. This caffeic acid formation (Y) correlated positively and linearly to p-coumaric acid consumption (X): Y = 0.5 X + 9.5; R (2) = 0.96, P < 0.0001. The kinetics of caffeic acid formation with time in response to initial p-coumaric acid levels and at different grape skin concentrations, indicated that the grape skins harboured an o-hydroxylation activity, proposedly a monophenol- or a flavonoid 3'-monooxygenase activity (EC 1.14.18.1 or EC 1.14.13.21). The K (m) of this crude o-hydroxylation activity in the red grape skin was 0.5 mM with p-coumaric acid.

[Influence of simulated acid rain on nitrogen and phosphorus contents and their stoichiome-tric ratios of tea organs in a red soil region, China].

PubMed

Zhang, Yu Fei; Fang, Xiang Min; Chen, Fu Sheng; Zong, Ying Ying; Gu, Han Jiao; Hu, Xiao Fei

2017-04-18

A 25-year-old tea plantation in a typical red soil region was selected for an in situ simulated acid rain experiment treated by pH 4.5, 3.5, 2.5 and water (control, CK). Roots with different functions, leaves and twigs with different ages were collected to measure nitrogen (N) and phosphorus (P) contents in the third year after simulated acid rain treatment. The N/P and acid rain sensitivity coefficient of tea plant organs were also calculated. The results indicated that with the increase of acid rain intensity, the soil pH, NO 3 - -N and available P decreased, while the absorption root N content increased. Compared with the control, the N content in absorption root was increased by 32.9% under the treatment of pH 2.5. The P content in storage root significantly decreased with enhanced acid rain intensity, and the acid rain treatment significantly enhanced N/P of absorption root. Young and mature leaf N, P contents were not sensitive to different intensities of acid rain, but the mature leaf N/P was significantly increased under pH 3.5 treatment compared with the control. The effects of acid rain treatments differed with tea twig ages. Compared with the control, low intensity acid treatment (pH 4.5) significantly increased young twig N content and N/P, while no signi-ficant differences in old twig N content and N/P were observed among four acid rain treatments. Acid rain sensitivity coefficients of absorption root, young leaf and twig N contents were higher than that of storage root, old leaf and twig, respectively. And the storage root and leaf P had higher acid rain sensitivity coefficient than other tea organs. In sum, tea organs N content was sensitive to acid rain treatment, and moderate acid rain could increase young organ N content and N/P, and change the cycle and balance of N and P in tea plantation.

Acid mediates a prolonged antinociception via substance P signaling in acid-induced chronic widespread pain.

PubMed

Chen, Wei-Nan; Chen, Chih-Cheng

2014-05-21

Substance P is an important neuropeptide released from nociceptors to mediate pain signals. We recently revealed antinociceptive signaling by substance P in acid-sensing ion channel 3 (ASIC3)-expressing muscle nociceptors in a mouse model of acid-induced chronic widespread pain. However, methods to specifically trigger the substance P antinociception were still lacking. Here we show that acid could induce antinociceptive signaling via substance P release in muscle. We prevented the intramuscular acid-induced hyperalgesia by pharmacological inhibition of ASIC3 and transient receptor potential V1 (TRPV1). The antinociceptive effect of non-ASIC3, non-TRPV1 acid signaling lasted for 2 days. The non-ASIC3, non-TRPV1 acid antinociception was largely abolished in mice lacking substance P. Moreover, pretreatment with substance P in muscle mimicked the acid antinociceptive effect and prevented the hyperalgesia induced by next-day acid injection. Acid could mediate a prolonged antinociceptive signaling via the release of substance P from muscle afferent neurons in a non-ASIC3, non-TRPV1 manner.

Regional oesophageal sensitivity to acid and weakly acidic reflux in patients with non-erosive reflux disease.

PubMed

Emerenziani, S; Ribolsi, M; Sifrim, D; Blondeau, K; Cicala, M

2009-03-01

The mechanisms underlying symptoms in non-erosive reflux disease (NERD) remain to be elucidated. Non-erosive reflux disease patients appear to be more sensitive to intraluminal stimula than erosive patients, the proximal oesophagus being the most sensitive. In order to assess regional oesophageal changes in reflux acidity and sensitivity to reflux, according either to the acidity or the composition of the refluxate, combined multiple pH and multiple pH-impedance (pH-MII) was performed in 16 NERD patients. According to multiple pH-metry, 29% and 12% of reflux events reached the middle and proximal oesophagus respectively, and 35% and 19% according to conventional pH-MII (P < 0.05). The per-individual analysis confirmed the difference between the two techniques. According to combined distal and proximal pH-MII, approximately 30% of distal acid reflux became weakly acidic at the proximal oesophagus. In all patients, the frequency of symptomatic refluxes, both acid and weakly acidic, was significantly higher at the proximal, compared with distal oesophagus (25 +/- 8%vs 11 +/- 2% for acid reflux and 27 +/- 8%vs 8 +/- 2% for weakly acidic reflux; P < 0.05). Compared with multiple pH-metry, pH-MII shows a higher sensitivity in the detection of proximal reflux. As approximately 30% of acid reflux becomes weakly acidic along the oesophageal body, to better characterize proximal reflux, in clinical practice, combined proximal pH-impedance monitoring should be used. In NERD patients, the proximal oesophagus seems to be more sensitive to both acid and weakly acidic reflux.

In silico Analysis for Predicting Fatty Acids of Black Cumin Oil as Inhibitors of P-Glycoprotein.

PubMed

Ali, Babar; Jamal, Qazi Mohd Sajid; Mir, Showkat R; Shams, Saiba; Al-Wabel, Naser A; Kamal, Mohammad A

2015-10-01

Black cumin oil is obtained from the seeds of Nigella sativa L. which belongs to family Ranunculaceae. The seed oil has been reported to possess antitumor, antioxidant, antibacterial, anti-inflammatory, hypoglycemic, central nervous system depressant, antioxidant, and immunostimulatory activities. These bioactivities have been attributed to the fixed oil, volatile oil, or their components. Seed oil consisted of 15 saturated fatty acids (17%) and 17 unsaturated fatty acids (82.9%). Long chain fatty acids and medium chain fatty acids have been reported to increase oral bioavailability of peptides, antibiotics, and other important therapeutic agents. In earlier studies, permeation enhancement and bioenhancement of drugs has been done with black cumin oil. In order to recognize the mechanism of binding of fatty acids to P-glycoprotein (P-gp), linoleic acid, oleic acid, margaric acid, cis-11, 14-eicosadienoic acid, and stearic acid were selected for in silico studies, which were carried out using AutoDock 4.2, based on the Lamarckian genetic algorithm principle. Template search with BLAST and HHblits has been performed against the SWISS-MODEL template library. The target sequence was searched with BLAST against the primary amino acid sequence of P-gp from Rattus norvegicus. The amount of energy needed by linoleic acid, oleic acid, eicosadienoic acid, margaric acid, and stearic acid to bind with P-gp were found to be - 10.60, -10.48, -9.95, -11.92, and - 10.37 kcal/mol, respectively. The obtained data support that all the selected fatty acids have contributed to inhibit P-gp activity thereby enhances the bioavailability of drugs. This study plays a significant role in finding hot spots in P-gp and may offer the further scope of designing potent and specific inhibitors of P-gp. Generation of 3D structure of fatty acid compounds from Black cumin oil and 3D homology modeling of Rat P glycoprotein as a receptor.Rat P-gp structure quality shows 88.5% residues in favored region obtained by Ramchandran plot analysis.Docking analysis revealed that Some amino acids common for all compounds like Ser221, Pro222, Ile224, Gly225, Ser228, Ala229, Lys233, Tyr302, Tyr309, Ile337, Leu338 and Thr341 in the P-gp and ligands binding patterns.Eicosadeinoic acid has highest binding affinity with P-gp as the amount of energy needed to bind with P-gp was lowest (-11.92 kcal/mol). Abbreviations used: P-gp: P-glycoprotein.

Function of the minor duodenal papilla in pancreas divisum as determined by duodenoscopy using indigo carmine dye and a pH sensor.

PubMed

Ohshima, Y; Tsukamoto, Y; Naitoh, Y; Hirooka, Y; Furukawa, T; Nakagawa, H; Hayakawa, T

1994-12-01

The objective of this study was to evaluate the function of the minor duodenal papilla and to investigate the relationship between the history of acute pancreatitis and individual dorsal pancreatogram findings and the minor papilla function in pancreas divisum. Eight of the 21 patients with PD diagnosed by endoscopic retrograde cholangiopancreatography had a history of acute pancreatitis (group A), and 13 patients did not (group B). The reaction of pancreatic juice excreted via the minor papilla was evaluated after intravenous administration of secretin, by observing the repulsion of indigo carmine dye scattered on the surface of the minor papilla. The function of the minor papilla was classified into two types. In 12 patients, all of the pigment on the minor papilla was repelled within 5 min of secretin administration (type I), and in the remaining nine patients it was not (type II). After secretin administration, the pH of the minor papilla surface in type I was significantly higher than that in type II. There was no significant difference between the type I and type II patients in exocrine pancreatic function, as evaluated by a BT-PABA test. In the group A patients, the rate of occurrence of dorsal duct dilation (including changes of the terminal shape) was significantly greater than in the group B patients. The function of the minor papilla in the group A patients was significantly worse than in the group B patients. Outflow obstruction of pancreatic group B patients. Outflow obstruction of pancreatic juice, i.e., "relative stenosis of the minor papilla," was considered to be present in the patients with type II papilla, and, therefore, the patients with type II papilla might suffer from acute pancreatitis resulting from poor drainage of pancreatic juice and excessive pressure in the dorsal duct. The finding that patients with PD have one of two types of minor papilla will be useful for understanding the condition and selecting the therapeutic plan for individual patients.

p21 induction plays a dual role in anti-cancer activity of ursolic acid

PubMed Central

Zhang, Xudong; Song, Xinhua; Yin, Shutao; Zhao, Chong; Fan, Lihong

2015-01-01

Previous studies have shown that induction of G1 arrest and apoptosis by ursolic acid is associated with up-regulation of cyclin-dependent kinase inhibitor (CDKI) protein p21 in multiple types of cancer cells. However, the functional role of p21 induction in G1 cell cycle arrest and apoptosis, and the mechanisms of p21 induction by ursolic acid have not been critically addressed. In the current study, we demonstrated that p21 played a mediator role in G1 cell cycle arrest by ursolic acid, whereas p21-mediated up-regulation of Mcl-1 compromised apoptotic effect of ursolic acid. These results suggest that p21 induction plays a dual role in the anti-cancer activity of ursolic acid in terms of cell cycle and apoptosis regulation. p21 induction by ursolic acid was attributed to p53 transcriptional activation. Moreover, we found that ursolic acid was able to inhibit murine double minute-2 protein (MDM2) and T-LAK cell-originated protein kinase (TOPK), the two negative regulator of p53, which in turn contributed to ursolic acid-induced p53 activation. Our findings provided novel insights into understanding of the mechanisms involved in cell cycle arrest and apoptosis induction in response to ursolic acid exposure. PMID:26582056

Demonstration of in situ product recovery of butyric acid via CO2 -facilitated pH swings and medium development in two-phase partitioning bioreactors.

PubMed

Peterson, Eric C; Daugulis, Andrew J

2014-03-01

Production of organic acids in solid-liquid two-phase partitioning bioreactors (TPPBs) is challenging, and highly pH-dependent, as cell growth occurs near neutral pH, while acid sorption occurs only at low pH conditions. CO2 sparging was used to achieve acidic pH swings, facilitating undissociated organic acid uptake without generating osmotic stress inherent in traditional acid/base pH control. A modified cultivation medium was formulated to permit greater pH reduction by CO2 sparging (pH 4.8) compared to typical media (pH 5.3), while still possessing adequate nutrients for extensive cell growth. In situ product recovery (ISPR) of butyric acid (pKa = 4.8) produced by Clostridium tyrobutyricum was achieved through intermittent CO2 sparging while recycling reactor contents through a column packed with absorptive polymer Hytrel® 3078. This polymer was selected on the basis of its composition as a polyether copolymer, and the use of solubility parameters for predicting solute polymer affinity, and was found to have a partition coefficient for butyric acid of 3. Total polymeric extraction of 3.2 g butyric acid with no CO2 mediated pH swings was increased to 4.5 g via CO2 -facilitated pH shifting, despite the buffering capacity of butyric acid, which resists pH shifting. This work shows that CO2 -mediated pH swings have an observable positive effect on organic acid extraction, with improvements well over 150% under optimal conditions in early stage fermentation compared to CO2 -free controls, and this technique can be applied other organic acid fermentations to achieve or improve ISPR. © 2013 Wiley Periodicals, Inc.

Adaptive responses of Bacillus cereus ATCC14579 cells upon exposure to acid conditions involve ATPase activity to maintain their internal pH

PubMed Central

Senouci-Rezkallah, Khadidja; Jobin, Michel P; Schmitt, Philippe

2015-01-01

This study examined the involvement of ATPase activity in the acid tolerance response (ATR) of Bacillus cereus ATCC14579 strain. In the current work, B. cereus cells were grown in anaerobic chemostat culture at external pH (pHe) 7.0 or 5.5 and at a growth rate of 0.2 h−1. Population reduction and internal pH (pHi) after acid shock at pH 4.0 was examined either with or without ATPase inhibitor N,N’-dicyclohexylcarbodiimide (DCCD) and ionophores valinomycin and nigericin. Population reduction after acid shock at pH 4.0 was strongly limited in cells grown at pH 5.5 (acid-adapted cells) compared with cells grown at pH 7.0 (unadapted cells), indicating that B. cereus cells grown at low pHe were able to induce a significant ATR and Exercise-induced increase in ATPase activity. However, DCCD and ionophores had a negative effect on the ability of B. cereus cells to survive and maintain their pHi during acid shock. When acid shock was achieved after DCCD treatment, pHi was markedly dropped in unadapted and acid-adapted cells. The ATPase activity was also significantly inhibited by DCCD and ionophores in acid-adapted cells. Furthermore, transcriptional analysis revealed that atpB (ATP beta chain) transcripts was increased in acid-adapted cells compared to unadapted cells before and after acid shock. Our data demonstrate that B. cereus is able to induce an ATR during growth at low pH. These adaptations depend on the ATPase activity induction and pHi homeostasis. Our data demonstrate that the ATPase enzyme can be implicated in the cytoplasmic pH regulation and in acid tolerance of B. cereus acid-adapted cells. PMID:25740257

40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite p...

40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite p...

40 CFR 180.202 - p-Chlorophenoxyacetic acid; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false p-Chlorophenoxyacetic acid; tolerances... Tolerances § 180.202 p-Chlorophenoxyacetic acid; tolerances for residues. (a) General. A tolerance is established for the combined residues of the plant regulator p-chlorophenoxyacetic acid and its metabolite p...

Cutaneous biocompatible rutin-loaded gelatin-based nanoparticles increase the SPF of the association of UVA and UVB filters.

PubMed

Oliveira, Camila Areias de; Peres, Daniela D'Almeida; Graziola, Fabiana; Chacra, Nádia Araci Bou; Araújo, Gabriel Lima Barros de; Flórido, Ana Catarina; Mota, Joana; Rosado, Catarina; Velasco, Maria Valéria Robles; Rodrigues, Luís Monteiro; Fernandes, Ana Sofia; Baby, André Rolim

2016-01-01

The encapsulation of natural ingredients, such as rutin, can offer improvements in sun protection effectiveness. This strategy can provide enhanced flavonoid content and produces an improved bioactive compound with new physical and functional characteristics. As an alternative to common synthetic-based sunscreens, rutin-entrapped gelatin nanoparticles (GNPs) were designed and associated with ethylhexyl dimethyl PABA (EHDP), ethylhexyl methoxycinnamate (EHMC) and methoxydibenzoylmethane (BMDBM) in sunscreen formulations. The purpose of this study was to develop rutin-loaded gelatin nanoparticles and characterize their physicochemical, thermal, functional and safety properties. Rutin-loaded gelatin nanoparticles increased antioxidant activity by 74% relative to free-rutin (FR) solution. Also, this new ingredient upgraded the Sun Protection Factor (SPF) by 48%, indicating its potential as a raw material for bioactive sunscreens. The safety profile indicated that GNPs and glutaraldehyde (GTA) decreased HaCaT cell viability in a concentration/time-dependent manner. However, both blank nanoparticles (B-NC) and rutin-loaded nanoparticles (R-NC) had good performance on skin compatibility tests. These results functionally characterized rutin-loaded nanoparticles as a safe SPF enhancer in sunscreens, especially in association with UV filters. Copyright © 2015 Elsevier B.V. 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.

Effect of low-molecular-weight organic acids on kinetics release and fractionation of phosphorus in some calcareous soils of western Iran.

PubMed

Taghipour, M; Jalali, M

2013-07-01

Organic acid has been related to nutrient mobilization, mainly in phosphorus (P) insoluble utilization, and therefore enhances P bioavailability. In this study, we examined the effect of low-molecular-weight organic acids (malic, citric, and oxalic acids) on P release of some calcareous soils from western Iran. Fractionation and speciation of P in the soil solution were studied at the initial and final P release. Significantly different quantities of P were extracted by the organic acids. On average the maximum (1,554.9 mg kg(-1)) and the minimum (1,260.5 mg kg(-1)) P were extracted by 10 mM oxalic and malic acid, respectively. Power equation described well P release. In the initial stage of P release, the solution samples in soils were supersaturated with respect to hydroxyapatite and β-TCP. At the end of P release, all solutions were undersaturated with phosphate minerals. The percentage of Fe-Al oxide fraction generally increased after P release, while carbonate and residual P fractions were decreased in all organic acids. Compared with the native soils, adding malic and citric acids had no effect on Fe-Al oxide fraction, but oxalic acid significantly reduced this fraction.

Net alkalinity and net acidity 2: Practical considerations

USGS Publications Warehouse

Kirby, C.S.; Cravotta, C.A.

2005-01-01

The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH < 6.3 after oxidation had positive Hot Acidity. Samples with similar pH values before oxidation had dissimilar Hot Acidities due to variations in their alkalinities and dissolved Fe, Mn, and Al concentrations. Hot Acidity was approximately equal to net acidity calculated based on initial pH and dissolved concentrations of Fe, Mn, and Al minus the initial alkalinity. Acidity calculated from the pH and dissolved metals concentrations, assuming equivalents of 2 per mole of Fe and Mn and 3 per mole of Al, was equivalent to that calculated based on complete aqueous speciation of FeII/FeIII. Despite changes in the pH, alkalinity, and metals concentrations, the Hot Acidities were comparable for fresh and most aged samples. A meaningful "net" acidity can be determined from a measured Hot Acidity or by calculation from the pH, alkalinity, and dissolved metals concentrations. The use of net alkalinity = (Alkalinitymeasured - Hot Aciditymeasured) to design mine drainage treatment can lead to systems with insufficient Alkalinity to neutralize metal and H+ acidity and is not recommended. The use of net alkalinity = -Hot Acidity titration is recommended for the planning of mine drainage treatment. The use of net alkalinity = (Alkalinitymeasured - Aciditycalculated) is recommended with some cautions. ?? 2005 Elsevier Ltd. All rights reserved.

PA-1, a Versatile Anaerobe Obtained in Pure Culture, Catabolizes Benzenoids and Other Compounds in Syntrophy with Hydrogenotrophs, and P-2 plus Wolinella sp. Degrades Benzenoids

PubMed Central

Barik, Sudhakar; Brulla, W. J.; Bryant, M. P.

1985-01-01

Methanogenic enrichments catabolizing 13 mM phenylacetate or 4 mM phenol were established at 37°C, using a 10% inoculum from a municipal anaerobic digester. By using agar roll tubes of the basal medium plus 0.1% yeast extract-25 mM fumarate, a hydrogenotrophic lawn of Wolinella succinogenes and phenol or phenylacetate, strains P-2 and PA-1, respectively, were isolated in coculture with W. succinogenes. With the lawn deleted, PA-1 was isolated in pure culture. Strain P-2 is apparently a new species of anaerobic, motile, gram-negative, spindle-shaped, small rod that as yet has been grown only in coculture with W. succinogenes. It used phenol, hydrocinnamate, benzoate, and phenylacetate as energy sources. Product recovery by the coculture, per mole of phenol and 4.4 mol of fumarate used, included 2.03, 0.12, 0.08, and 3.23 mol, respectively, of acetate, propionate, butyrate, and succinate. Carbon recovery was 75% and H recovery was 80%, although CO2 and a few other possible products were not determined. That P-2 is an obligate proton-reducing acetogen and possible pathways for its degradation of phenol are discussed. Strain PA-1 is apparently a new species of anaerobic, motile, relatively small, gram-negative rod. It utilized compounds such as phenylacetate, hydrocinnamate, benzoate, phenol, resorcinol, gallate, 4-aminophenol, 2-aminobenzoate, pyruvate, Casamino Acids, and aspartate as energy sources in coculture with W. succinogenes. Per mole of phenylacetate and 1.44 mol of fumarate used, 1.04, 0.53, and 0.78 mol of acetate, propionate, and succinate, respectively, were recovered from the coculture. Only about 50% of the carbon and H were recovered. In coculture with Methanospirillum hungatei, 0.96 mol of acetate and 0.25 mol of methane were recovered per mol of pyruvate used; 0.90 mol of acetate and 0.33 mol of methane, per mol of fumarate used; 0.93 mol of acetate and 0.54 mol of methane, per mol of aspartate used; and 1.71 mol of acetate and 0.57 mol of methane, per mol of glucose used. Carbon and H recoveries, assuming CO2 and ammonia were produced in stoichiometric amounts, were 97 and 98% for pyruvate, 72.5 and 82% for fumarate, 96.5 and 98% for aspartate, and 61.8 and 76% for glucose. No explanation such as contamination could be found for the fact that the coculture PA-1 plus Wolinella sp. did not use glucose; after growth with M. hungatei on pyruvate, however, the latter coculture used glucose. The PA-1 pure culture produced 0.86 mol of propionate per mol of succinate used during growth. PA-1 produced a small amount of H2. Strain PA-1 is the most versatile anaerobic bacterium yet known that catabolizes monobenzenoids in the absence of electron acceptors such as sulfate or nitrate. PMID:16346852

Effects of alpha lipoic acid, ascorbic acid-6-palmitate, and fish oil on the glutathione, malonaldehyde, and fatty acids levels in erythrocytes of streptozotocin induced diabetic male rats.

PubMed

Yilmaz, Okkeş; Ozkan, Yusuf; Yildirim, Mehmet; Oztürk, A Ihsan; Erşan, Yasemin

2002-01-01

In this research, it has been aimed to evaluate the improvement effects of alpha lipoic acid (ALA), ascorbic acid-6-palmitate (AA6P), fish oil (FO), and their combination (COM) on some biochemical properties in erythrocytes of streptozotocin (STZ)-induced diabetic male rats. According to experimental results, glutathione (GSH) level in erythrocytes decreased in diabetes (P < 0.01), D + ALA, and D + AA6P groups (P < 0.001). Malonaldehyde (MA) level increased in diabetes (P < 0.05), D + FO, and D + COM groups (P < 0.001), but its level in D + AA6P and D + ALA groups was lower in diabetes group (P < 0.01). Total lipid level in diabetes and diabetes plus antioxidant administered groups were higher than control. Total cholesterol level was high in diabetes and D + ALA groups (P < 0.05), but its level reduced in D + FO compared to control and diabetes groups, P < 0.05, < 0.001, respectively. Total triglyceride (TTG) level was high in the D + ALA (P < 0.05) and D + COM (P < 0.001) groups. In contrast, TTG level in blood of diabetes group was higher than diabetes plus antioxidant and FO administered groups (P < 0.001). According to gas chromatography analysis results, while the palmitic acid raised in diabetes group (P < 0.05), stearic acid in D + FO, D + ALA, and diabetes groups was lower than control (P < 0.05), oleic acid reduced in D + COM and D + FO groups, but its level raised in D + AA6P and D + ALA groups (P < 0.01). As the linoleic acid (LA) elevated in ALA + D, D + AA6P, and diabetes groups, linolenic acid level in diabetes, D + AA6P, and D + FO groups was lower than control (P < 0.001). Arachidonic acid (AA) decreased in D + ALA, D+ AA6P, and diabetes groups (P < 0.01), but its level in D + COM and D + FO was higher than control (P < 0.05). Docosahexaenoic acid (DHA) increased in D + AA6P and D + COM (P < 0.05). While the total saturated fatty acid level raised in diabetes group, its level reduced in D + ALA and D + FO groups (P < 0.05). In contrast, total unsaturated fatty acid level in D + ALA and D + FO groups was higher than control (P < 0.05). In conclusion, present data have confirmed that the combination of the ALA, AA6P, and FO have improvement effects on the recycling of GSSG to reduced GSH in erythrocytes of diabetic rats, and in addition to this, oxidative stress was suppressed by ALA and AA6P, and unsaturated fatty acid degree was raised by the effects of ALA and FO. Copyright 2002 Wiley-Liss, Inc.

Influence of polysorbate 80 and cyclopropane fatty acid synthase activity on lactic acid production by Lactobacillus casei ATCC 334 at low pH.

PubMed

Broadbent, J R; Oberg, T S; Hughes, J E; Ward, R E; Brighton, C; Welker, D L; Steele, J L

2014-03-01

Lactic acid is an important industrial chemical commonly produced through microbial fermentation. The efficiency of acid extraction is increased at or below the acid's pKa (pH 3.86), so there is interest in factors that allow for a reduced fermentation pH. We explored the role of cyclopropane synthase (Cfa) and polysorbate (Tween) 80 on acid production and membrane lipid composition in Lactobacillus casei ATCC 334 at low pH. Cells from wild-type and an ATCC 334 cfa knockout mutant were incubated in APT broth medium containing 3 % glucose plus 0.02 or 0.2 % Tween 80. The cultures were allowed to acidify the medium until it reached a target pH (4.5, 4.0, or 3.8), and then the pH was maintained by automatic addition of NH₄OH. Cells were collected at the midpoint of the fermentation for membrane lipid analysis, and media samples were analyzed for lactic and acetic acids when acid production had ceased. There were no significant differences in the quantity of lactic acid produced at different pH values by wild-type or mutant cells grown in APT, but the rate of acid production was reduced as pH declined. APT supplementation with 0.2 % Tween 80 significantly increased the amount of lactic acid produced by wild-type cells at pH 3.8, and the rate of acid production was modestly improved. This effect was not observed with the cfa mutant, which indicated Cfa activity and Tween 80 supplementation were each involved in the significant increase in lactic acid yield observed with wild-type L. casei at pH 3.8.

Acidic and basic solutions dissolve protein plugs made of lithostathine complicating choledochal cyst/pancreaticobiliary maljunction.

PubMed

Kaneko, Kenitiro; Ono, Yasuyuki; Tainaka, Takahisa; Sumida, Wataru; Ando, Hisami

2009-07-01

Symptoms of choledochal cysts are caused by protein plugs made of lithostathine, which block the long common channel and increase pancreaticobiliary ductal pressure. Agents that dissolve protein plugs can provide relief from or prevent symptoms. In the present study, drugs reportedly effective for pancreatic and biliary stones were used in dissolution tests. Protein plugs were obtained from choledochal cysts during surgery in two children (5- and 6-year-old girls). Plugs approximately 2 mm in diameter were immersed in citric acid, tartaric acid, dimethadione, bromhexine, dehydrocholic acid, sodium citrate, hydrochloric acid, and sodium hydroxide solutions under observation with a digital microscope. The pH of each solution was measured using a pH meter. Plugs dissolved in citric acid (5.2 mM; pH 2.64), tartaric acid (6.7 mM; pH 2.51), dimethadione (75 mM; pH 3.70), hydrochloric acid (0.5 mM; pH 3.13), and sodium hydroxide (75 mM; pH 12.75) solutions. Plugs did not dissolve in dimethadione (7.5 mM; pH 4.31), bromhexine (0.1%; pH 4.68), dehydrocholic acid (5%; pH 7.45), and sodium citrate (75 mM; pH 7.23) solutions. Protein plugs in choledochal cysts are dissolved in acidic and basic solutions, which may eliminate longitudinal electrostatic interactions of the lithostathine protofibrils.

Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice

PubMed Central

Jusop, Shamshuddin; Naher, Umme Aminun; Othman, Radziah; Razi, Mohd Ismail

2013-01-01

A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg−1), plant P uptake (0.78 P pot−1), and plant biomass (33.26 mg). Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g−1) compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH. PMID:24288473

Sulfuric acid induces airway hyperresponsiveness to substance P in the guinea pig.

PubMed

Stengel, P W; Bendele, A M; Cockerham, S L; Silbaugh, S A

1993-01-01

We investigated whether sulfuric acid inhalation would cause hyperresponsiveness to substance P. Guinea pigs became dyspneic during a 1 h sulfuric acid exposure, but recovered by 24 h when they were challenged with substance P or histamine aerosols. Eight minutes after the start of challenge, animals were killed and excised lung gas volumes measured. Sulfuric acid slightly increased histamine responsiveness compared to controls. However, sulfuric acid caused a much more pronounced leftward shift in the dose response to substance P. Coadministration of the neutral endopeptidase (NEP) inhibitor, thiorphan, did not reduce sulfuric acid-related hyperresponsiveness to substance P. By 72 h, sensitization to substance P was absent. Histological evaluation of sulfuric acid-treated lungs revealed mild alveolitis at 24 h, but not at 72 h. We conclude that sulfuric acid produces a marked sensitization to substance P. Inactivation of NEP does not appear to account for this effect.

Esophageal Acid Clearance During Random Swallowing Is Faster in Patients with Barrett’s Esophagus Than in Healthy Controls

PubMed Central

Lottrup, Christian; Krarup, Anne L; Gregersen, Hans; Ejstrud, Per; Drewes, Asbjørn M

2016-01-01

Background/Aims Impaired esophageal acid clearance may be a contributing factor in the pathogenesis of Barrett’s esophagus. However, few studies have measured acid clearance as such in these patients. In this explorative, cross-sectional study, we aimed to compare esophageal acid clearance and swallowing rate in patients with Barrett’s esophagus to that in healthy controls. Methods A total of 26 patients with histology-confirmed Barrett’s esophagus and 12 healthy controls underwent (1) upper endoscopy, (2) an acid clearance test using a pH-impedance probe under controlled conditions including controlled and random swallowing, and (3) an ambulatory pH-impedance measurement. Results Compared with controls and when swallowing randomly, patients cleared acid 46% faster (P = 0.008). Furthermore, patients swallowed 60% more frequently (mean swallows/minute: 1.90 ± 0.74 vs 1.19 ± 0.58; P = 0.005), and acid clearance time decreased with greater random swallowing rate (P < 0.001). Swallowing rate increased with lower distal esophageal baseline impedance (P = 0.014). Ambulatory acid exposure was greater in patients (P = 0.033), but clearance times assessed from the ambulatory pH-measurement and acid clearance test were not correlated (all P > 0.3). Conclusions More frequent swallowing and thus faster acid clearance in Barrett’s esophagus may constitute a protective reflex due to impaired mucosal integrity and possibly acid hypersensitivity. Despite these reinforced mechanisms, acid clearance ability seems to be overthrown by repeated, retrograde acid reflux, thus resulting in increased esophageal acid exposure and consequently mucosal changes. PMID:27557545

Amino acid substitutions in random mutagenesis libraries: lessons from analyzing 3000 mutations.

PubMed

Zhao, Jing; Frauenkron-Machedjou, Victorine Josiane; Kardashliev, Tsvetan; Ruff, Anna Joëlle; Zhu, Leilei; Bocola, Marco; Schwaneberg, Ulrich

2017-04-01

The quality of amino acid substitution patterns in random mutagenesis libraries is decisive for the success in directed evolution campaigns. In this manuscript, we provide a detailed analysis of the amino acid substitutions by analyzing 3000 mutations of three random mutagenesis libraries (1000 mutations each; epPCR with a low-mutation and a high-mutation frequency and SeSaM-Tv P/P) employing lipase A from Bacillus subtilis (bsla). A comparison of the obtained numbers of beneficial variants in the mentioned three random mutagenesis libraries with a site saturation mutagenesis (SSM) (covering the natural diversity at each amino acid position of BSLA) concludes the diversity analysis. Seventy-six percent of the SeSaM-Tv P/P-generated substitutions yield chemically different amino acid substitutions compared to 64% (epPCR-low) and 69% (epPCR-high). Unique substitutions from one amino acid to others are termed distinct amino acid substitutions. In the SeSaM-Tv P/P library, 35% of all theoretical distinct amino acid substitutions were found in the 1000 mutation library compared to 25% (epPCR-low) and 26% (epPCR-high). Thirty-six percent of distinct amino acid substitutions found in SeSaM-Tv P/P were unobtainable by epPCR-low. Comparison with the SSM library showed that epPCR-low covers 15%, epPCR-high 18%, and SeSaM-Tv P/P 21% of obtainable beneficial amino acid positions. In essence, this study provides first insights on the quality of epPCR and SeSaM-Tv P/P libraries in terms of amino acid substitutions, their chemical differences, and the number of obtainable beneficial amino acid positions.

Production of Skatole and para-Cresol by a Rumen Lactobacillus sp. †

PubMed Central

Yokoyama, Melvin T.; Carlson, James R.

1981-01-01

The objective of this study was to examine the substrate specificity of several ruminal strains of a Lactobacillus sp. which previously was shown to produce skatole (3-methylindole) by the decarboxylation of indoleacetic acid. A total of 13 compounds were tested for decarboxylase activity. The Lactobacillus strains produced p-cresol (4-methylphenol) by the decarboxylation of p-hydroxyphenylacetic acid, but did not produce either o-cresol or m-cresol from the corresponding hydroxyphenylacetic acid isomers. These strains also decarboxylated 5-hydroxyindoleacetic acid to 5-hydroxyskatole and 3,4-dihydroxyphenylacetic acid to methylcatechol. Skatole and p-cresol were produced in a 0.5:1 ratio, when indoleacetic acid and p-hydroxyphenylacetic acid were combined in equimolar concentrations. Competition studies with indoleacetic acid and p-hydroxyphenylacetic acid suggested that two different decarboxylating enzymes are involved in the production of skatole and p-cresol by these strains. This is the first demonstration of both skatole production and p-cresol production by a single bacterium. PMID:16345702

RhoA mediates the expression of acidic extracellular pH-induced matrix metalloproteinase-9 mRNA through phospholipase D1 in mouse metastatic B16-BL6 melanoma cells.

PubMed

Maeda, Toyonobu; Yuzawa, Satoshi; Suzuki, Atsuko; Baba, Yuh; Nishimura, Yukio; Kato, Yasumasa

2016-03-01

Solid tumors are characterized by acidic extracellular pH (pHe). The present study examined the contribution of small GTP-binding proteins to phospholipase D (PLD) activation of acidic pHe-induced matrix metalloproteinase-9 (MMP-9) production. Acidic pHe-induced MMP-9 production was reduced by C3 exoenzyme, which inhibits the Rho family of GTPases; cytochalasin D, which inhibits actin reorganization; and simvastatin, which inhibits geranylgeranylation of Rho. Small interfering RNA (siRNA) against RhoA, but not against Rac1 or Cdc42, significantly inhibited acidic pHe induction of MMP-9. Pull-down assays showed that acidic pHe increased the activated form of RhoA. Forced expression of constitutively active RhoA induced MMP-9 production, even at neutral pHe. RhoA siRNA also reduced acidic pHe induced PLD activity. Specific inhibition of PLD1 and Pld1 gene knockout significantly reduced acidic pHe-induced MMP-9 expression. In contrast, PLD2 inhibition or knockout had no effect on MMP-9 expression. These findings suggested that RhoA-PLD1 signaling is involved in acidic pHe induction of MMP-9.

Alteration of chemical behavior of L-ascorbic acid in combination with nickel sulfate at different pH solutions in vitro

PubMed Central

Maniyar, Shaheen A; Jargar, Jameel G; Das, Swastika N; Dhundasi, Salim A; Das, Kusal K

2012-01-01

Objective To evaluate the alteration of chemical behavior of L-ascorbic acid (vitamin C) with metal ion (nickel) at different pH solutions in vitro. Methods Spectra of pure aqueous solution of L-ascorbic acid (E mark) compound and NiSO4 (H2O) (sigma USA) were evaluated by UV visible spectrophotometer. Spectral analysis of L-ascorbic acid and nickel at various pH (2.0, 7.0, 7.4 and 8.6) at room temperature of 29 °C was recorded. In this special analysis, combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded. Results The result revealed that λmax (peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 nm whereas at neutral pH 7.0, λmax was 295.4 nm. In alkaline pH 8.6, λmax was 295.4 nm and at pH 7.4 the λmax of L-ascorbic acid remained the same as 295.4 nm. Nickel solution at acidic pH 2.0 was 394.5 nm, whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm. But at alkaline pH 8.6, λmax value of nickel sulfate became 392.0 nm. The combined solution of L-ascorbic acid and nickel sulfate (6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm, respectively whereas at pH 7.0, L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm. At pH 7.4, L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6 (alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm, respectively. Conclusions Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH. Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical (HSc*) generation from the reaction of H2ASc + Ni (II) is the cause of such alteration of λmax value of L-ascorbic acid in the presence of metal nickel. PMID:23569901

Variation in pH optima of hydrolytic enzyme activities in tropical rain forest soils.

PubMed

Turner, Benjamin L

2010-10-01

Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.

Bifidobacterium breve with α-linolenic acid and linoleic acid alters fatty acid metabolism in the maternal separation model of irritable bowel syndrome.

PubMed

Barrett, Eoin; Fitzgerald, Patrick; Dinan, Timothy G; Cryan, John F; Ross, R Paul; Quigley, Eamonn M; Shanahan, Fergus; Kiely, Barry; Fitzgerald, Gerald F; O'Toole, Paul W; Stanton, Catherine

2012-01-01

The aim of this study was to compare the impact of dietary supplementation with a Bifidobacterium breve strain together with linoleic acid & α-linolenic acid, for 7 weeks, on colonic sensitivity and fatty acid metabolism in rats. Maternally separated and non-maternally separated Sprague Dawley rats (n = 15) were orally gavaged with either B. breve DPC6330 (10(9) microorganisms/day) alone or in combination with 0.5% (w/w) linoleic acid & 0.5% (w/w) α-linolenic acid, daily for 7 weeks and compared with trehalose and bovine serum albumin. Tissue fatty acid composition was assessed by gas-liquid chromatography and visceral hypersensitivity was assessed by colorectal distension. Significant differences in the fatty acid profiles of the non-separated controls and maternally separated controls were observed for α-linolenic acid and arachidonic acid in the liver, oleic acid and eicosenoic acid (c11) in adipose tissue, and for palmitoleic acid and docosahexaenoic acid in serum (p<0.05). Administration of B. breve DPC6330 to MS rats significantly increased palmitoleic acid, arachidonic acid and docosahexaenoic acid in the liver, eicosenoic acid (c11) in adipose tissue and palmitoleic acid in the prefrontal cortex (p<0.05), whereas feeding B. breve DPC6330 to non separated rats significantly increased eicosapentaenoic acid and docosapentaenoic acid in serum (p<0.05) compared with the NS un-supplemented controls. Administration of B. breve DPC6330 in combination with linoleic acid and α-linolenic acid to maternally separated rats significantly increased docosapentaenoic acid in the serum (p<0.01) and α-linolenic acid in adipose tissue (p<0.001), whereas feeding B. breve DPC6330 with fatty acid supplementation to non-separated rats significantly increased liver and serum docosapentaenoic acid (p<0.05), and α-linolenic acid in adipose tissue (p<0.001). B. breve DPC6330 influenced host fatty acid metabolism. Administration of B. breve DPC6330 to maternally separated rats significantly modified the palmitoleic acid, arachidonic acid and docosahexaenoic acid contents in tissues. The effect was not observed in non-separated animals.

Bifidobacterium breve with α-Linolenic Acid and Linoleic Acid Alters Fatty Acid Metabolism in the Maternal Separation Model of Irritable Bowel Syndrome

PubMed Central

Barrett, Eoin; Fitzgerald, Patrick; Dinan, Timothy G.; Cryan, John F.; Ross, R. Paul; Quigley, Eamonn M.; Shanahan, Fergus; Kiely, Barry; Fitzgerald, Gerald F.; O'Toole, Paul W.; Stanton, Catherine

2012-01-01

The aim of this study was to compare the impact of dietary supplementation with a Bifidobacterium breve strain together with linoleic acid & α-linolenic acid, for 7 weeks, on colonic sensitivity and fatty acid metabolism in rats. Maternally separated and non-maternally separated Sprague Dawley rats (n = 15) were orally gavaged with either B. breve DPC6330 (109 microorganisms/day) alone or in combination with 0.5% (w/w) linoleic acid & 0.5% (w/w) α-linolenic acid, daily for 7 weeks and compared with trehalose and bovine serum albumin. Tissue fatty acid composition was assessed by gas-liquid chromatography and visceral hypersensitivity was assessed by colorectal distension. Significant differences in the fatty acid profiles of the non-separated controls and maternally separated controls were observed for α-linolenic acid and arachidonic acid in the liver, oleic acid and eicosenoic acid (c11) in adipose tissue, and for palmitoleic acid and docosahexaenoic acid in serum (p<0.05). Administration of B. breve DPC6330 to MS rats significantly increased palmitoleic acid, arachidonic acid and docosahexaenoic acid in the liver, eicosenoic acid (c11) in adipose tissue and palmitoleic acid in the prefrontal cortex (p<0.05), whereas feeding B. breve DPC6330 to non separated rats significantly increased eicosapentaenoic acid and docosapentaenoic acid in serum (p<0.05) compared with the NS un-supplemented controls. Administration of B. breve DPC6330 in combination with linoleic acid and α-linolenic acid to maternally separated rats significantly increased docosapentaenoic acid in the serum (p<0.01) and α-linolenic acid in adipose tissue (p<0.001), whereas feeding B. breve DPC6330 with fatty acid supplementation to non-separated rats significantly increased liver and serum docosapentaenoic acid (p<0.05), and α-linolenic acid in adipose tissue (p<0.001). B. breve DPC6330 influenced host fatty acid metabolism. Administration of B. breve DPC6330 to maternally separated rats significantly modified the palmitoleic acid, arachidonic acid and docosahexaenoic acid contents in tissues. The effect was not observed in non-separated animals. PMID:23185248

Production of hydroxycinnamoyl-shikimates and chlorogenic acid in Escherichia coli: production of hydroxycinnamic acid conjugates

PubMed Central

2013-01-01

Background Hydroxycinnamates (HCs) are mainly produced in plants. Caffeic acid (CA), p-coumaric acid (PA), ferulic acid (FA) and sinapic acid (SA) are members of the HC family. The consumption of HC by human might prevent cardiovascular disease and some types of cancer. The solubility of HCs is increased through thioester conjugation to various compounds such as quinic acid, shikimic acid, malic acid, anthranilic acid, and glycerol. Although hydroxycinnamate conjugates can be obtained from diverse plant sources such as coffee, tomato, potato, apple, and sweet potato, some parts of the world have limited availability to these compounds. Thus, there is growing interest in producing HC conjugates as nutraceutical supplements. Results Hydroxycinnamoyl transferases (HCTs) including hydroxycinnamate-CoA shikimate transferase (HST) and hydroxycinnamate-CoA quinate transferase (HQT) were co-expressed with 4-coumarateCoA:ligase (4CL) in Escherichia coli cultured in media supplemented with HCs. Two hydroxycinnamoyl conjugates, p-coumaroyl shikimates and chlorogenic acid, were thereby synthesized. Total 29.1 mg/L of four different p-coumaroyl shikimates (3-p-coumaroyl shikimate, 4-p-coumaroyl shikimate, 3,4-di-p-coumaroyl shikimate, 3,5-di-p-coumaroyl shikimate, and 4,5-di-p-coumaroyl shikimate) was obtained and 16 mg/L of chlorogenic acid was synthesized in the wild type E. coli strain. To increase the concentration of endogenous acceptor substrates such as shikimate and quinate, the shikimate pathway in E. coli was engineered. A E. coli aroL and aroK gene were mutated and the resulting mutants were used for the production of p-coumaroyl shikimate. An E. coli aroD mutant was used for the production of chlorogenic acid. We also optimized the vector and cell concentration optimization. Conclusions To produce p-coumaroyl-shikimates and chlorogenic acid in E. coli, several E. coli mutants (an aroD mutant for chlorogenic acid production; an aroL, aroK, and aroKL mutant for p-coumaroyl-shikimates production) were made and each mutant was tested using an optimized construct. Using this strategy, we produced 235 mg/L of p-coumaroyl-shikimates and 450 mg/L of chlorogenic acid. PMID:23383718

Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2'-bipyridyl, lipoic, kojic and picolinic acids.

PubMed

Çevik, Kübra; Ulusoy, Seyhan

2015-08-01

The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. The inhibitory activity of 2,2'-bipyridyl, lipoic acid, kojic acid and picolinic acid on biofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa PAK01, P. aeruginosa PAK02 and P. aeruginosa PAK03) were investigated, based on crystal violet assay, and swarming motility test. The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84%) and kojic acid (68%) presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation.

[Effect of phosphate and organic acid addition on passivation of simulated Pb contaminated soil and the stability of the product].

PubMed

Zuo, Ji-Chao; Gao, Ting-Ting; Su, Xiao-Juan; Wan, Tian-Ying; Hu, Hong-Qing

2014-10-01

Organic acids can improve the phosphorus availability, influence the immobilization of heavy metals in soil, and has very complicated function in phosphorus activation and heavy metal passivation. This research took simulated Pb contaminated soil as material, phosphate and citric acid as remediation matter, adopted BCR continuous extraction, 0.01 mol · L(-1) CaCl2 and toxicity characteristic leaching procedure (TCLP) to evaluate the remediation effect. Besides, malic acid and NaNO3 were taken as desorption reagents to discuss the stability of the phosphorus-citric acid-Pb system. The results showed that: in the absence of citric acid, the amount of acid extracted Pb decreased along with the increase of P concentration; when the P concentration was 100 and 400 mg · kg(-1), acid extractable Pb increased with the increasing of citric acid concentration. However, residual Pb changed in the opposite direction from acid extractable Pb. The phenomenon showed that P improved the bioavailability of Pb, while citric acid had the opposite effect. With a certain organic acid concentration, extractable Pb contents extracted by 0.01 mol · L(-1) CaCl2 and TCLP both decreased with the increasing P concentration, therefore, P had immobilization effect on Pb in contaminated soil. But at a fixed P concentration, extractable Pb contents by 0.01 mol · L(-1) CaCl2 and TCLP changed in the opposite trend with the increasing citric acid concentration. The desorption rate of Pb in soil increased with the increasing malic acid concentration, the decreasing pH and the increasing ionic strength. The desorption extent of Pb in soil with P only was lower than that with both P and citric acid. But the stability of Pb passivated by the former was higher.

Organic Acids Regulation of Chemical-Microbial Phosphorus Transformations in Soils.

PubMed

Menezes-Blackburn, Daniel; Paredes, Cecilia; Zhang, Hao; Giles, Courtney D; Darch, Tegan; Stutter, Marc; George, Timothy S; Shand, Charles; Lumsdon, David; Cooper, Patricia; Wendler, Renate; Brown, Lawrie; Blackwell, Martin; Wearing, Catherine; Haygarth, Philip M

2016-11-01

We have used an integrated approach to study the mobility of inorganic phosphorus (P) from soil solid phase as well as the microbial biomass P and respiration at increasing doses of citric and oxalic acid in two different soils with contrasting agronomic P status. Citric or oxalic acids significantly increased soil solution P concentrations for doses over 2 mmol kg -1 . However, low organic acid doses (<2 mmol kg -1 ) were associated with a steep increase in microbial biomass P, which was not seen for higher doses. In both soils, treatment with the tribasic citric acid led to a greater increase in soil solution P than the dibasic oxalic acid, likely due to the rapid degrading of oxalic acids in soils. After equilibration of soils with citric or oxalic acids, the adsorbed-to-solution distribution coefficient (K d ) and desorption rate constants (k -1 ) decreased whereas an increase in the response time of solution P equilibration (T c ) was observed. The extent of this effect was shown to be both soil and organic acid specific. Our results illustrate the critical thresholds of organic acid concentration necessary to mobilize sorbed and precipitated P, bringing new insight on how the exudation of organic acids regulate chemical-microbial soil phosphorus transformations.

40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No. 1186211...

40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No. 1186211...

40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No. 1186211...

Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning.

PubMed

Soltani, Motahareh; Shetab-Boushehri, Seyed F; Shetab-Boushehri, Seyed V

2016-08-01

Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.

Evaluation of the efficacy of four weak acids as antifungal preservatives in low-acid intermediate moisture model food systems.

PubMed

Huang, Yang; Wilson, Mark; Chapman, Belinda; Hocking, Ailsa D

2010-02-01

The potential efficacy of four weak acids as preservatives in low-acid intermediate moisture foods was assessed using a glycerol based agar medium. The minimum inhibitory concentrations (MIC, % wt./wt.) of each acid was determined at two pH values (pH 5.0, pH 6.0) and two a(w) values (0.85, 0.90) for five food spoilage fungi, Eurotium herbariorum, Eurotium rubrum, Aspergillus niger, Aspergillus flavus and Penicillium roqueforti. Sorbic acid, a preservative commonly used to control fungal growth in low-acid intermediate moisture foods, was included as a reference. The MIC values of the four acids were lower at pH 5.0 than pH 6.0 at equivalent a(w) values, and lower at 0.85 a(w) than 0.90 a(w) at equivalent pH values. By comparison with the MIC values of sorbic acid, those of caprylic acid and dehydroacetic acid were generally lower, whereas those for caproic acid were generally higher. No general observation could be made in the case of capric acid. The antifungal activities of all five weak acids appeared related not only to the undissociated form, but also the dissociated form, of each acid.

Medium pH, carbon and nitrogen concentrations modulate the phosphate solubilization efficiency of Penicillium purpurogenum through organic acid production.

PubMed

Scervino, J M; Papinutti, V L; Godoy, M S; Rodriguez, M A; Della Monica, I; Recchi, M; Pettinari, M J; Godeas, A M

2011-05-01

To study phosphate solubilization in Penicillium purpurogenum as function of medium pH, and carbon and nitrogen concentrations. Tricalcium phosphate (CP) solubilization efficiency of P. purpurogenum was evaluated at acid or alkaline pH using different C and N sources. Glucose- and (NH(4) )(2) SO(4) -based media showed the highest P solubilization values followed by fructose. P. purpurogenum solubilizing ability was higher in cultures grown at pH 6·5 than cultures at pH 8·5. Organic acids were detected in both alkaline and neutral media, but the relative percentages of each organic acid differed. Highest P release coincided with the highest organic acids production peak, especially gluconic acid. When P. purpurogenum grew in alkaline media, the nature and concentration of organic acids changed at different N and C concentrations. A factorial categorical experimental design showed that the highest P-solubilizing activity, coinciding with the highest organic acid production, corresponded to the highest C concentration and lowest N concentration. The results described in the present study show that medium pH and carbon and nitrogen concentrations modulate the P solubilization efficiency of P. purpurogenum through the production of organic acids and particularly that of gluconic acid. In the P solubilization optimization studies, glucose and (NH(4) )(2) SO(4) as C and N sources allowed a higher solubilization efficiency at high pH. This organism is a potentially proficient soil inoculant, especially in P-poor alkaline soils where other P solubilizers fail to release soluble P. Further work is necessary to elucidate whether these results can be extrapolated to natural soil ecosystems, where different pH values are present. Penicillium purpurogenum could be used to develop a bioprocess for the manufacture of phosphatic fertilizer with phosphate calcium minerals. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

[Effects of simulated acid rain on decomposition of soil organic carbon and crop straw].

PubMed

Zhu, Xue-Zhu; Huang, Yao; Yang, Xin-Zhong

2009-02-01

To evaluate the effects of acid rain on the organic carbon decomposition in different acidity soils, a 40-day incubation test was conducted with the paddy soils of pH 5.48, 6.70 and 8.18. The soils were amended with 0 and 15 g x kg(-1) of rice straw, adjusted to the moisture content of 400 g x kg(-1) air-dried soil by using simulated rain of pH 6.0, 4.5, and 3.0, and incubated at 20 degrees C. The results showed that straw, acid rain, and soil co-affected the CO2 emission from soil system. The amendment of straw increased the soil CO2 emission rate significantly. Acid rain had no significant effects on soil organic carbon decomposition, but significantly affected the straw decomposition in soil. When treated with pH 3.0 acid rain, the amount of decomposed straw over 40-day incubation in acid (pH 5.48) and alkaline (pH 8.18) soils was 8% higher, while that in neutral soil (pH 6.70) was 15% lower, compared to the treatment of pH 6.0 rain. In the treatment of pH 3.0 acid rain, the decomposition rate of soil organic C in acid (pH 5.48) soil was 43% and 50% (P < 0.05) higher than that in neutral (pH 6.70) and alkaline (pH 8.18) soils, while the decomposition rate of straw in neutral soil was 17% and 16% (P < 0.05) lower than that in acid and alkaline soils, respectively.

Nestedness in Arbuscular Mycorrhizal Fungal Communities along Soil pH Gradients in Early Primary Succession: Acid-Tolerant Fungi Are pH Generalists

PubMed Central

Kawahara, Ai; An, Gi-Hong; Miyakawa, Sachie; Sonoda, Jun

2016-01-01

Soil acidity is a major constraint on plant productivity. Arbuscular mycorrhizal (AM) fungi support plant colonization in acidic soil, but soil acidity also constrains fungal growth and diversity. Fungi in extreme environments generally evolve towards specialists, suggesting that AM fungi in acidic soil are acidic-soil specialists. In our previous surveys, however, some AM fungi detected in strongly acidic soils could also be detected in a soil with moderate pH, which raised a hypothesis that the fungi in acidic soils are pH generalists. To test the hypothesis, we conducted a pH-manipulation experiment and also analyzed AM fungal distribution along a pH gradient in the field using a synthesized dataset of the previous and recent surveys. Rhizosphere soils of the generalist plant Miscanthus sinensis were collected both from a neutral soil and an acidic soil, and M. sinensis seedlings were grown at three different pH. For the analysis of field communities, rhizosphere soils of M. sinensis were collected from six field sites across Japan, which covered a soil pH range of 3.0–7.4, and subjected to soil trap culture. AM fungal community compositions were determined based on LSU rDNA sequences. In the pH-manipulation experiment the acidification of medium had a significant impact on the compositions of the community from the neutral soil, but the neutralization of the medium had no effect on those of the community from the acidic soil. Furthermore, the communities in lower -pH soils were subsets of (nested in) those in higher-pH soils. In the field communities a significant nestedness pattern was observed along the pH gradient. These observations suggest that the fungi in strongly acidic soils are pH generalists that occur not only in acidic soil but also in wide ranges of soil pH. Nestedness in AM fungal community along pH gradients may have important implications for plant community resilience and early primary succession after disturbance in acidic soils. PMID:27755574

Nestedness in Arbuscular Mycorrhizal Fungal Communities along Soil pH Gradients in Early Primary Succession: Acid-Tolerant Fungi Are pH Generalists.

PubMed

Kawahara, Ai; An, Gi-Hong; Miyakawa, Sachie; Sonoda, Jun; Ezawa, Tatsuhiro

2016-01-01

Soil acidity is a major constraint on plant productivity. Arbuscular mycorrhizal (AM) fungi support plant colonization in acidic soil, but soil acidity also constrains fungal growth and diversity. Fungi in extreme environments generally evolve towards specialists, suggesting that AM fungi in acidic soil are acidic-soil specialists. In our previous surveys, however, some AM fungi detected in strongly acidic soils could also be detected in a soil with moderate pH, which raised a hypothesis that the fungi in acidic soils are pH generalists. To test the hypothesis, we conducted a pH-manipulation experiment and also analyzed AM fungal distribution along a pH gradient in the field using a synthesized dataset of the previous and recent surveys. Rhizosphere soils of the generalist plant Miscanthus sinensis were collected both from a neutral soil and an acidic soil, and M. sinensis seedlings were grown at three different pH. For the analysis of field communities, rhizosphere soils of M. sinensis were collected from six field sites across Japan, which covered a soil pH range of 3.0-7.4, and subjected to soil trap culture. AM fungal community compositions were determined based on LSU rDNA sequences. In the pH-manipulation experiment the acidification of medium had a significant impact on the compositions of the community from the neutral soil, but the neutralization of the medium had no effect on those of the community from the acidic soil. Furthermore, the communities in lower -pH soils were subsets of (nested in) those in higher-pH soils. In the field communities a significant nestedness pattern was observed along the pH gradient. These observations suggest that the fungi in strongly acidic soils are pH generalists that occur not only in acidic soil but also in wide ranges of soil pH. Nestedness in AM fungal community along pH gradients may have important implications for plant community resilience and early primary succession after disturbance in acidic soils.

In vitro metabolism of radiolabeled carbohydrates by protective cecal anaerobic bacteria.

PubMed

Hume, M E; Beier, R C; Hinton, A; Scanlan, C M; Corrier, D E; Peterson, D V; DeLoach, J R

1993-12-01

Cecal anaerobic bacteria from adult broilers were cultured in media containing .25% glucose or .25% lactose. Media also contained either [14C]-labeled lactose, glucose, galactose, or lactic acid as metabolic tracers. Cultures were analyzed at 4, 8, and 12 h for pH, radiolabeled and unlabeled volatile fatty acids, and lactic acid. The pH values of cultures containing .25% lactose were significantly (P < .05) higher than the pH values of cultures containing .25% glucose. Lactose cultures reached their lowest pH more slowly than glucose cultures. Concentrations of unlabeled volatile fatty acids increased and lactic acid decreased during incubation of the cultures. Radiolabeled sugars and lactic acid were more readily metabolized to volatile fatty acids in media containing lactose than in media containing glucose. The preferred metabolism of [14C]substrates, independent of media carbohydrate, was in the following order: lactic acid > galactose, lactose > glucose. The volatile fatty acids in which radiolabel was most concentrated were acetic acid, propionic acid, or butyric acid.

Influence of long-term exposure to simulated acid rain on development, reproduction and acaricide susceptibility of the carmine spider mite, Tetranychus cinnabarinus

PubMed Central

Wang, Jin-Jun; Zhang, Jian-Ping; He, Lin; Zhao, Zhi-Mo

2006-01-01

Development, reproduction and acaricide susceptibility of Tetranychus cinnabarinus (Boisduvals) (Acari: Tetranychidae) were investigated after long-term (about 40 generations) exposure to various levels of acid rain; pH 2.5, 3.0, 4.0, and 5.6. Deionized water (pH 6.8) served as a control. The mites were reared on eggplant leaves at 28°C, 80%RH and a photoperiod of 14:10 (L:D) in the laboratory. The results showed that the duration of the immature stage was significantly affected by acid rain exposure. The shortest duration (8.90 days) was recorded for populations exposed to pH 5.6 acid rain, while the longest duration (9.37 days) occurred after exposure to pH 2.5 acid rain. Compared with the control population, adult longevity was shortened with an increase in acidity. Similarly, the oviposition duration was also shortened by an increase in acidity. Statistically, female fecundity did not differ significantly between pH 5.6, pH 4.0 and control populations, but did differ significantly between the control population and those exposed to pH 2.5 and pH 3.0 acid rain. This suggested that the mite suffered reproductive defects after long-term exposure to acid rain with higher acidity (pH 2.5 and 3.0). The intrinsic rate of increase among different populations was not significantly affected, but the net reproductive rate of populations exposed to pH 2.5 and 3.0 acid rain was significantly less than pH4.0, 5.6, and control populations. Bioassay results showed that after long-term exposure to acid rain, susceptibility of the mites to two acaricides, dichlorvos and fenpropathrin, did not change significantly. PMID:19537978

The weak acid preservative sorbic acid inhibits conidial germination and mycelial growth of Aspergillus niger through intracellular acidification.

PubMed

Plumridge, Andrew; Hesse, Stephan J A; Watson, Adrian J; Lowe, Kenneth C; Stratford, Malcolm; Archer, David B

2004-06-01

The growth of the filamentous fungus Aspergillus niger, a common food spoilage organism, is inhibited by the weak acid preservative sorbic acid (trans-trans-2,4-hexadienoic acid). Conidia inoculated at 10(5)/ml of medium showed a sorbic acid MIC of 4.5 mM at pH 4.0, whereas the MIC for the amount of mycelia at 24 h developed from the same spore inoculum was threefold lower. The MIC for conidia and, to a lesser extent, mycelia was shown to be dependent on the inoculum size. A. niger is capable of degrading sorbic acid, and this ability has consequences for food preservation strategies. The mechanism of action of sorbic acid was investigated using (31)P nuclear magnetic resonance (NMR) spectroscopy. We show that a rapid decline in cytosolic pH (pH(cyt)) by more than 1 pH unit and a depression of vacuolar pH (pH(vac)) in A. niger occurs in the presence of sorbic acid. The pH gradient over the vacuole completely collapsed as a result of the decline in pH(cyt). NMR spectra also revealed that sorbic acid (3.0 mM at pH 4.0) caused intracellular ATP pools and levels of sugar-phosphomonoesters and -phosphodiesters of A. niger mycelia to decrease dramatically, and they did not recover. The disruption of pH homeostasis by sorbic acid at concentrations below the MIC could account for the delay in spore germination and retardation of the onset of subsequent mycelial growth.

Physiological analysis of the effects of rikkunshito on acid and non-acid gastroesophageal reflux using pH-multichannel intraluminal impedance monitoring.

PubMed

Kawahara, Hisayoshi; Tazuke, Yuko; Soh, Hideki; Yoneda, Akihiro; Fukuzawa, Masahiro

2014-09-01

To clarify the effects of rikkunshito on acid reflux, non-acid reflux, and esophageal clearance in patients with gastroesophageal reflux disease (GERD). We enrolled seven patients with vomiting and/or stridor (median 6 years; 1 month-17 years), with a percent total time of esophageal pH <4.0 (reflux index) over 4.0%. Rikkunshito (TJ-43; Tsumura Co, Tokyo, Japan) was given in three divided doses before meals. We retrospectively investigated its efficacy using pH-multichannel intraluminal impedance before and 7 (6-10) days after starting treatment. Statistical analyses were conducted using Wilcoxon signed-rank test. In the pH analyses alone, the median number of acid reflux episodes >5 min (14 versus 10, p = 0.046) and median acid-clearance time (184 versus 134 s, p = 0.03) decreased significantly, although median decrease in reflux index did not reach significance (16.0 versus 17.9%, p = 0.06). In the combined impedance and pH analyses, the median number (36 versus 36, p = 0.03) and median duration (1.9 versus 1.1%, p = 0.046) of acid reflux decreased significantly; non-acid reflux and bolus clearance time did not change. Rikkunshito effectively reduced acid reflux, but not esophageal clearance, in patients with GERD.

Acidic pH modulation of Na+ channels in trigeminal mesencephalic nucleus neurons.

PubMed

Kang, In-Sik; Cho, Jin-Hwa; Choi, In-Sun; Kim, Do-Yeon; Jang, Il-Sung

2016-12-07

Cell bodies of trigeminal mesencephalic nucleus (Vmes) neurons are located within the central nervous system, and therefore, peripheral as well as central acidosis can modulate the excitability of Vmes neurons. Here, we report the effect of acidic pH on voltage-gated Na channels in acutely isolated rat Vmes neurons using a conventional whole-cell patch clamp technique. Acidic pH (pH 6.0) slightly but significantly shifted both the activation and steady-state fast inactivation relationships toward depolarized potentials. However, acidic pH (pH 6.0) had a minor effect on the inactivation kinetics of voltage-gated Na channels. Less sensitivity of voltage-gated Na channels to acidic pH may allow Vmes neurons to transduce the precise proprioceptive information even under acidic pH conditions.

Biodegradation of Lignin Monomers Vanillic, p-Coumaric, and Syringic Acid by the Bacterial Strain, Sphingobacterium sp. HY-H.

PubMed

Wang, Jinxing; Liang, Jidong; Gao, Sha

2018-05-10

Many bacterial strains have been demonstrated to biodegrade lignin for contaminant removal or resource regeneration. The goal of this study was to investigate the biodegradation amount and associated pathways of three lignin monomers, vanillic, p-coumaric, and syringic acid by strain Sphingobacterium sp. HY-H. Vanillic, p-coumaric, and syringic acid degradation with strain HY-H was estimated as 88.71, 76.67, and 72.78%, respectively, after 96 h. Correspondingly, the same three monomers were associated with a COD removal efficiency of 87.30, 55.17, and 67.23%, and a TOC removal efficiency of 82.14, 61.03, and 43.86%. The results of GC-MS, HPLC, FTIR, and enzyme activities show that guaiacol and o-dihydroxybenzene are key intermediate metabolites of the vanillic acid and syringic acid degradation. p-Hydroxybenzoic acid is an important intermediate metabolite for p-coumaric and syringic acid degradation. LiP and MnP play an important role in the degradation of lignin monomers and their intermediate metabolites. One possible pathway is that strain HY-H degrades lignin monomers into guaiacol (through decarboxylic and demethoxy reaction) or p-hydroxybenzoic acid (through side-chain oxidation); then guaiacol demethylates to o-dihydroxybenzene. The p-hydroxybenzoic acid and o-dihydroxybenzene are futher through ring cleavage reaction to form small molecule acids (butyric, valproic, oxalic acid, and propionic acid) and alcohols (ethanol and ethanediol), then these acids and alcohols are finally decomposed into CO 2 and H 2 O through the tricarboxylic acid cycle. If properly optimized and controlled, the strain HY-H may play a role in breaking down lignin-related compounds for biofuel and chemical production.

Acid-adapted strains of Escherichia coli K-12 obtained by experimental evolution.

PubMed

Harden, Mark M; He, Amanda; Creamer, Kaitlin; Clark, Michelle W; Hamdallah, Issam; Martinez, Keith A; Kresslein, Robert L; Bush, Sean P; Slonczewski, Joan L

2015-03-01

Enteric bacteria encounter a wide range of pHs throughout the human intestinal tract. We conducted experimental evolution of Escherichia coli K-12 to isolate clones with increased fitness during growth under acidic conditions (pH 4.5 to 4.8). Twenty-four independent populations of E. coli K-12 W3110 were evolved in LBK medium (10 g/liter tryptone, 5 g/liter yeast extract, 7.45 g/liter KCl) buffered with homopiperazine-N,N'-bis-2-(ethanosulfonic acid) and malate at pH 4.8. At generation 730, the pH was decreased to 4.6 with HCl. By 2,000 generations, all populations had achieved higher endpoint growth than the ancestor at pH 4.6 but not at pH 7.0. All evolving populations showed a progressive loss of activity of lysine decarboxylase (CadA), a major acid stress enzyme. This finding suggests a surprising association between acid adaptation and moderation of an acid stress response. At generation 2,000, eight clones were isolated from four populations, and their genomes were sequenced. Each clone showed between three and eight missense mutations, including one in a subunit of the RNA polymerase holoenzyme (rpoB, rpoC, or rpoD). Missense mutations were found in adiY, the activator of the acid-inducible arginine decarboxylase (adiA), and in gcvP (glycine decarboxylase), a possible acid stress component. For tests of fitness relative to that of the ancestor, lacZ::kan was transduced into each strain. All acid-evolved clones showed a high fitness advantage at pH 4.6. With the cytoplasmic pH depressed by benzoate (at external pH 6.5), acid-evolved clones showed decreased fitness; thus, there was no adaptation to cytoplasmic pH depression. At pH 9.0, acid-evolved clones showed no fitness advantage. Thus, our acid-evolved clones showed a fitness increase specific to low external pH. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Acid-Adapted Strains of Escherichia coli K-12 Obtained by Experimental Evolution

PubMed Central

Harden, Mark M.; He, Amanda; Creamer, Kaitlin; Clark, Michelle W.; Hamdallah, Issam; Martinez, Keith A.; Kresslein, Robert L.; Bush, Sean P.

2015-01-01

Enteric bacteria encounter a wide range of pHs throughout the human intestinal tract. We conducted experimental evolution of Escherichia coli K-12 to isolate clones with increased fitness during growth under acidic conditions (pH 4.5 to 4.8). Twenty-four independent populations of E. coli K-12 W3110 were evolved in LBK medium (10 g/liter tryptone, 5 g/liter yeast extract, 7.45 g/liter KCl) buffered with homopiperazine-N,N′-bis-2-(ethanosulfonic acid) and malate at pH 4.8. At generation 730, the pH was decreased to 4.6 with HCl. By 2,000 generations, all populations had achieved higher endpoint growth than the ancestor at pH 4.6 but not at pH 7.0. All evolving populations showed a progressive loss of activity of lysine decarboxylase (CadA), a major acid stress enzyme. This finding suggests a surprising association between acid adaptation and moderation of an acid stress response. At generation 2,000, eight clones were isolated from four populations, and their genomes were sequenced. Each clone showed between three and eight missense mutations, including one in a subunit of the RNA polymerase holoenzyme (rpoB, rpoC, or rpoD). Missense mutations were found in adiY, the activator of the acid-inducible arginine decarboxylase (adiA), and in gcvP (glycine decarboxylase), a possible acid stress component. For tests of fitness relative to that of the ancestor, lacZ::kan was transduced into each strain. All acid-evolved clones showed a high fitness advantage at pH 4.6. With the cytoplasmic pH depressed by benzoate (at external pH 6.5), acid-evolved clones showed decreased fitness; thus, there was no adaptation to cytoplasmic pH depression. At pH 9.0, acid-evolved clones showed no fitness advantage. Thus, our acid-evolved clones showed a fitness increase specific to low external pH. PMID:25556191

Discovery of Clinically Approved Agents That Promote Suppression of Cystic Fibrosis Transmembrane Conductance Regulator Nonsense Mutations.

PubMed

Mutyam, Venkateshwar; Du, Ming; Xue, Xiaojiao; Keeling, Kim M; White, E Lucile; Bostwick, J Robert; Rasmussen, Lynn; Liu, Bo; Mazur, Marina; Hong, Jeong S; Falk Libby, Emily; Liang, Feng; Shang, Haibo; Mense, Martin; Suto, Mark J; Bedwell, David M; Rowe, Steven M

2016-11-01

Premature termination codons (PTCs) in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF). Several agents are known to suppress PTCs but are poorly efficacious or toxic. To determine whether there are clinically available agents that elicit translational readthrough and improve CFTR function sufficient to confer therapeutic benefit to patients with CF with PTCs. Two independent screens, firefly luciferase and CFTR-mediated transepithelial chloride conductance assay, were performed on a library of 1,600 clinically approved compounds using fisher rat thyroid cells stably transfected with stop codons. Select agents were further evaluated using secondary screening assays including short circuit current analysis on primary cells from patients with CF. In addition, the effect of CFTR modulators (ivacaftor) was tested in combination with the most efficacious agents. From the primary screen, 48 agents were selected as potentially active. Following confirmatory tests in the transepithelial chloride conductance assay and prioritizing agents based on favorable pharmacologic properties, eight agents were advanced for secondary screening. Ivacaftor significantly increased short circuit current following forskolin stimulation in cells treated with pyranoradine tetraphosphate, potassium p-aminobenzoate, and escin as compared with vehicle control. Escin, an herbal agent, consistently induced readthrough activity as demonstrated by enhanced CFTR expression and function in vitro. Clinically approved drugs identified as potential readthrough agents, in combination with ivacaftor, may induce nonsense suppression to restore therapeutic levels of CFTR function. One or more agents may be suitable to advance to human testing.

Lipogenesis and lipid peroxidation in rat testes after long-term treatment with sucrose and tannic acid in drinking water.

PubMed

Mašek, T; Starčević, K

2017-05-01

We studied the influence of long-term treatment with sucrose and tannic acid in drinking water on the fatty acid profile and lipid peroxidation in rat testes. Male Wistar rats were supplemented with sucrose (30% w/v) or with sucrose and tannic acid (sucrose 30% w/v, tannic acid 0.1% w/v) in drinking water. The treatment with sucrose elevated blood glucose levels in the plasma (p < .05) and decreased the testis weight (p < .05) and testis index (p < .05) of the rats. Sucrose treatment increased monounsaturated fatty acids (MUFA) and C22:6n3, and decreased n6 fatty acids in testis tissue. Lipid peroxidation was significantly increased after sucrose administration in plasma (p < .05) and testis tissue (p < .01). The addition of tannic acid led to the decrease in lipid peroxidation in the plasma (p < .05) and testis (p < .05), a further increase in MUFA and decrease in n6 fatty acids. In conclusion, sucrose significantly altered the testis fatty acid profile with an increase in MUFA and C22:6n3, and a decrease in n6 fatty acids. Tannic acid attenuated oxidative stress and hyperglycaemia, but it did not improve pathological changes in the fatty acid composition of the testis. © 2016 Blackwell Verlag GmbH.

Acidic pH promotes intervertebral disc degeneration: Acid-sensing ion channel -3 as a potential therapeutic target.

PubMed

Gilbert, Hamish T J; Hodson, Nathan; Baird, Pauline; Richardson, Stephen M; Hoyland, Judith A

2016-11-17

The aetiology of intervertebral disc (IVD) degeneration remains poorly understood. Painful IVD degeneration is associated with an acidic intradiscal pH but the response of NP cells to this aberrant microenvironmental factor remains to be fully characterised. The aim here was to address the hypothesis that acidic pH, similar to that found in degenerate IVDs, leads to the altered cell/functional phenotype observed during IVD degeneration, and to investigate the involvement of acid-sensing ion channel (ASIC) -3 in the response. Human NP cells were treated with a range of pH, from that of a non-degenerate (pH 7.4 and 7.1) through to mildly degenerate (pH 6.8) and severely degenerate IVD (pH 6.5 and 6.2). Increasing acidity of pH caused a decrease in cell proliferation and viability, a shift towards matrix catabolism and increased expression of proinflammatory cytokines and pain-related factors. Acidic pH resulted in an increase in ASIC-3 expression. Importantly, inhibition of ASIC-3 prevented the acidic pH induced proinflammatory and pain-related phenotype in NP cells. Acidic pH causes a catabolic and degenerate phenotype in NP cells which is inhibited by blocking ASIC-3 activity, suggesting that this may be a useful therapeutic target for treatment of IVD degeneration.

Batch and fed-batch production of butyric acid by Clostridium butyricum ZJUCB

PubMed Central

He, Guo-qing; Kong, Qing; Chen, Qi-he; Ruan, Hui

2005-01-01

The production of butyric acid by Clostridium butyricum ZJUCB at various pH values was investigated. In order to study the effect of pH on cell growth, butyric acid biosynthesis and reducing sugar consumption, different cultivation pH values ranging from 6.0 to 7.5 were evaluated in 5-L bioreactor. In controlled pH batch fermentation, the optimum pH for cell growth and butyric acid production was 6.5 with a cell yield of 3.65 g/L and butyric acid yield of 12.25 g/L. Based on these results, this study then compared batch and fed-batch fermentation of butyric acid production at pH 6.5. Maximum value (16.74 g/L) of butyric acid concentration was obtained in fed-batch fermentation compared to 12.25 g/L in batch fermentation. It was concluded that cultivation under fed-batch fermentation mode could enhance butyric acid production significantly (P<0.01) by C. butyricum ZJUCB. PMID:16252341

Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2’-bipyridyl, lipoic, kojic and picolinic acids

PubMed Central

Çevik, Kübra; Ulusoy, Seyhan

2015-01-01

Objective(s): The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. Materials and Methods: The inhibitory activity of 2,2’-bipyridyl, lipoic acid, kojic acid and picolinic acid on biofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa PAK01, P. aeruginosa PAK02 and P. aeruginosa PAK03) were investigated, based on crystal violet assay, and swarming motility test. Results: The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84%) and kojic acid (68%) presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. Conclusion: It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation. PMID:26557964

Phosphorus recovery and leaching of trace elements from incinerated sewage sludge ash (ISSA).

PubMed

Fang, Le; Li, Jiang-Shan; Guo, Ming Zhi; Cheeseman, C R; Tsang, Daniel C W; Donatello, Shane; Poon, Chi Sun

2018-02-01

Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H 2 SO 4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning

PubMed Central

Soltani, Motahareh; Shetab-Boushehri, Seyed F.; Shetab-Boushehri, Seyed V.

2016-01-01

Objectives: Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning. PMID:27606109

Synergistic effect of acidity and extraframework position in faujasite on renewable p-xylene production

PubMed Central

2018-01-01

p-Xylene is a commodity chemical used for the manufacture of plastic bottles and textiles. For the biomass-based route from 2,5-dimethylfuran (DMF) and ethylene, the properties of the catalyst such as acidity effect, product selectivity and catalyst activity play an important role. To determine the effect of acidity and extraframework position in faujasite zeolite on p-xylene selectivity, type Y (Si/Al = 40 and Si/Al = 2.55) and X (Si/Al = 1.25) zeolites containing the extraframework Lewis acids Na+, K+, Li+, Ag+ and Cu+, and a Brønsted acid-containing zeolite, HY (Si/Al = 40), were prepared and tested for p-xylene production under solvent-free conditions and at low conversions (less than 35%). Here it is reported that NaX zeolite catalyses DMF and ethylene conversion to p-xylene with 91% selectivity at 30% conversion, which is better than the 25% p-xylene selectivity obtained when using HY at similar conversion. ANOVA was used to show that there is a synergistic effect between acidity and extraframework position on the rate of p-xylene production. At 7% DMF conversion, Lewis acids were more selective than the Brønsted acid tested (50 versus 30% p-xylene selectivity). p-Xylene selectivity is optimal when using Lewis acids with moderate acidity and extraframework positions located in the faujasite supercage (sites II and III). PMID:29892435

A mathematical model of pH, based on the total stoichiometric concentration of acids, bases and ampholytes dissolved in water.

PubMed

Mioni, Roberto; Mioni, Giuseppe

2015-10-01

In chemistry and in acid-base physiology, the Henderson-Hasselbalch equation plays a pivotal role in studying the behaviour of the buffer solutions. However, it seems that the general function to calculate the valence of acids, bases and ampholytes, N = f(pH), at any pH, has only been provided by Kildeberg. This equation can be applied to strong acids and bases, pluriprotic weak acids, bases and ampholytes, with an arbitrary number of acid strength constants, pKA, including water. By differentiating this function with respect to pH, we obtain the general equation for the buffer value. In addition, by integrating the titration curve, TA, proposed by Kildeberg, and calculating its Legendre transform, we obtain the Gibbs free energy of pH (or pOH)-dependent titratable acid. Starting from the law of electroneutrality and applying suitable simplifications, it is possible to calculate the pH of the buffer solutions by numerical methods, available in software packages such as Excel. The concept of buffer capacity has also been clarified by Urbansky, but, at variance with our approach, not in an organic manner. In fact, for each set of monobasic, dibasic, tribasic acids, etc., various equations are presented which independently fit each individual acid-base category. Consequently, with the increase in acid groups (pKA), the equations become more and more difficult, both in practice and in theory. Some examples are proposed to highlight the boundary that exists between acid-base physiology and the thermodynamic concepts of energy, chemical potential, amount of substance and acid resistance.