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At least 271 records · Page 15Linked to original sources
PubMed1994

Effects of para-aminobenzoic acid, insulin, and gentamicin on Plasmodium falciparum development in anopheline mosquitoes (Diptera: Culicidae).

Anopheles gambiae Giles sensu lato (s.l.) and An. stephensi Liston were exposed as adults to para-aminobenzoic acid (PABA), human insulin, or gentamicin sulfate, an antimicrobial solution, to determine their effects on Plasmodium falciparum Welch development to the oocyst stage. For both mosquito species, concentrations of PABA from 0.001 to 0.05% had no effect on either oocyst infection rates or oocyst densities. At higher concentrations, PABA-fed mosquitoes had decreased oocyst infection rates when they were exposed after, but not before, experimental infections. Insulin-fed mosquitoes had significantly higher oocyst infection rates than controls and increased oocyst densities in both An. gambiae s.l and An. stephensi. The most dramatic impact on parasite development was observed for mosquitoes fed on gentamicin. For An. gambiae s.l. fed 0.05% gentamicin, oocyst infection rates were 3.7-fold higher than in controls, whereas oocyst densities were 5.7 times greater than in controls. Anopheles stephensi fed on diets of 0.1% gentamicin had 2.4-fold higher infection rates and increased oocyst densities. Concentrations of gentamicin above 0.1% had deleterious effects on mosquito survival and their ability to digest blood meals. These findings provide insight into how antibiotics, hormones, and metabolites may affect the development of P. falciparum in An. gambiae s.l. and An. stephensi.

4-Aminobenzoic Acid↗
PubMed1991

Ultraviolet light induction of peripheral granulocytosis with splenomegaly: protection of mice with topical p-aminobenzoic acid (PABA).

Hairless mice were exposed to UVB irradiation from a Philips T1 12 light source. Mice that were exposed to UV-light and not protected with 5% p-aminobenzoic acid (PABA) showed a significantly higher number of peripheral blood granulocytes (P less than 0.001) and a significantly higher mean weight of both the spleen and the liver (P less than 0.001) than the non-irradiated controls. Light microscopy of the histology of the enlarged liver and spleen showed a proliferation of granulocytes and the reticuloendothelial cells. Treatment with topical PABA during the whole period of UV-exposure prevented the peripheral blood granulocytosis. These protected mice also had a significantly (P less than 0.001) lower mean weight for the liver and spleen than UV-exposed and non-protected mice.

4-Aminobenzoic Acid↗
PubMed1993

Organization of the genes encoding p-aminobenzoic acid synthetase from Streptomyces lividans 1326.

Genes involved in the biosynthesis of p-aminobenzoic acid (PABA) in Streptomyces lividans 1326 were cloned in pBR322 by complementing a pabB mutant of Escherichia coli. A 2.7-kb BamHI-SstI fragment of the cloned DNA complemented pabA and pabB mutations in both E. coli and S. lividans; complementation in S. lividans was accompanied by integration of the recombinant plasmid into the host chromosome. The nucleotide (nt) sequence of the 2.7-kb fragment contained two open reading frames, the deduced amino acid sequences of which were similar to those of pabA and pabB products from other bacteria. The nt sequences indicated that pabA and pabB are closely linked in S. lividans and supported cloning evidence that the genes are expressed from a promoter with features resembling those of most E. coli promoters.

Amino Acid Sequence↗
PubMed1998

Ortho-aminobenzoic acid as a fluorescent probe for the interaction between peptides and micelles.

Ortho-aminobenzoic acid (o-Abz) has been used as a fluorescent probe in internally quenched fluorescent peptides for continuous protease assays. We investigated the fluorescent properties of the probe in order to verify if it can be used to monitor the interaction of peptides with micelles. Abz-aminoacyl-monomethyl amides (Abz-Xaa-NHCH(3), where Xaa=Arg, Phe, Leu and Glu) were synthesized. Quantum yield, spectral position, anisotropy and lifetime decay were analyzed in the presence and absence of sodium dodecyl sulfate (SDS) micelles. Significant changes in the fluorescence parameters were observed for Abz-Arg-NHCH(3) in comparison to Abz-Glu-NHCH(3), indicating a strong electrostatic component in the compound's interaction with the negative charged micelles. The change in fluorescence parameters, observed when the probe is bound to hydrophobic amino acids Abz-Phe-NHCH(3) and Abz-Leu-NHCH(3), is probably due to insertion of those compounds into micelles. Abz-NHCH(3) fluorescence is less affected by the presence of micelles, indicating that the occurrence of interaction is dependent on the properties of the amino acid to which the fluorophore is attached. The quenching data with acrylamide confirmed these results. Titration curves allowed the estimation of association constants between Abz compounds and SDS, according to a single partition model. Although the results cannot be strictly applied to the titration with charged compounds, it was verified that the association constant for the isolated Abz-NHCH(3) is significantly lower than those for Abz-Phe-NHCH(3) and Abz-Leu-NHCH(3). It is concluded that the Abz group is a sensitive and convenient fluorescent probe to monitor peptide binding to amphiphilic aggregates. That conclusion is supported by measurements with the peptide Abz-Leu-Arg-Phe-NH(2).

Journal Article↗
PubMed1999

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

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.

Animals↗
PubMed1986

A multi-centre study on completeness of urine collection in 11 European centres. I. Some problems with the use of creatinine and 4-aminobenzoic acid as markers of the completeness of collection.

We have studied the completeness of urine collections in 11 European centres. The completeness of collection was examined by questioning the participants, by calculating the ratio of observed to expected creatinine, and by measuring the recovery of p-aminobenzoic acid (PABA) in the urine after administration of a 240 mg dose. The ratio of observed to expected creatinine is a fairly insensitive measure of undercollection. People who report that their collection is incomplete are likely to have collected incompletely to a considerable degree. It was concluded that the use of PABA in epidemiological studies is still questionable; overcollection cannot be detected by using PABA, and it appeared that people sometimes forget or refuse to take the capsules. It is also suggested that differences in the meal-time patterns between countries may interfere with the PABA recovery test.

4-Aminobenzoic Acid↗
PubMed1983

Plasmodium falciparum: variations in p-aminobenzoic acid requirements as related to sulfadoxine sensitivity.

Plasmodium falciparum, Thai strain FCM-5S sensitive to sulfadoxine, was grown continuously for 1 year in a medium with a low concentration of p-aminobenzoic acid (PABA) without the emergence of a sulfadoxine-resistant line. The minimum PABA-requirement for growth of sulfadoxine-sensitive Thai strains in vitro was found to be 25.0 ng/ml, whereas resistant Burmese and Gambian strains completed their schizogony in the absence of PABA. Cultivation in dialyzed and nondialyzed human serum suggested that the sulfadoxine-resistant parasite might use another serum factor in place of PABA for folate biosynthesis, thus overcoming the effect of sulfadoxine, a PABA antagonist. The significantly lower rate of [14C]sulfadoxine incorporation into erythrocytes infected with sulfadoxine-resistant strains strongly supports this suggestion.

4-Aminobenzoic Acid↗
PubMed2002

Gas chromatographic determination of 2-hydroxy-4-methoxybenzophenone and octyldimethyl-p-aminobenzoic acid sunscreen agents in swimming pool and bathing waters by solid-phase microextraction.

A method has been developed for the trace determination of two sunscreen constituents (2-hydroxy-4-methoxybenzophenone and octyldimethyl-p-aminobenzoic acid) in water samples, which are commonly used in commercial formulations. The method employs solid-phase microextraction (SPME) and gas chromatography with flame ionization and mass spectrometric detection. The technique was developed with headspace and direct sampling in order to demonstrate the applicability of these SPME extraction modes for the identification of these two UV absorbing compounds in waters. The main parameters affecting the SPME process, such as desorption time, extraction time profile, salt additives, pH, and temperature, were investigated. The poly(dimethylsiloxane) 100-microm and polyacrylate 85-microm fiber coatings were found to be the most efficient for the extraction of these compounds from aqueous matrices. Linear calibration curves in the wide range of 10-500 microg/l were obtained for both compounds yielding typical RSD values of 5-9% for both extraction modes. The recoveries were relatively high, 82-98%, with quantitation limits below 1 microg/l. A comparison between the proposed methods and the conventional multiresidue solid-phase extraction revealed that the proposed technique(s) can be reliably used for sunscreen residue measurement in water samples with satisfactory results.

4-Aminobenzoic Acid↗
PubMed1992

Inhibition of mutagenesis by p-aminobenzoic acid as a nitrite scavenger.

Nitrite treatment enhances the direct-acting mutagenicity of various foodstuffs (e.g., chicken, bloater, the soybean flour 'kinako', and Ban-Ban-Chi sauce) on Salmonella typhimurium TA100. p-Aminobenzoic acid (PABA) and glutathione (GSH) reduced this mutagenicity; on the other hand, thioproline (TPRO) increased it. PABA seemed more effective than TPRO in scavenging nitrite ion. In analysis of the reactions of PABA and sodium nitrite under acidic conditions (pH 3.0), p-hydroxybenzoic acid (PHBA) was identified as a major reaction product. The reaction seems to involve two steps, diazotization and diazonium substitution. PHBA was not mutagenic to four strains (TA97, TA98, TA100 and TA102) of S. typhimurium with or without S9 mix.

4-Aminobenzoic Acid↗
PubMed2006

Simultaneous determination of procaine and para-aminobenzoic acid by LC-MS/MS method.

A sensitive high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for simultaneous determination of procaine and its metabolite p-aminobenzoic acid (PABA). N-Acetylprocainamide (NAPA) was used as an internal standard for procaine and PABA analysis. This assay method has also been validated in terms of linearity, lower limit of detection, lower limit of quantitation, accuracy and precision as per ICH guidelines. Chromatography was carried out on an XTerra MS C(18) column and mass spectrometric analysis was performed using a Quattro Micro mass spectrometer working with electro-spray ionization (ESI) source in the positive ion mode. Enhanced selectivity was achieved using multiple reaction monitoring (MRM) functions, m/z 237-->100, m/z 138-->120, and m/z 278-->205 for procaine, PABA and NAPA, respectively. Retention times for PABA, procaine and NAPA were 4.0, 4.7 and 5.8min, respectively. Linearity for each calibration curve was observed across a range from 100nM to 5000nM for PABA, and from 10nM to 5000nM for procaine. The intra- and inter-day relative standard deviations (RSD) were <5%.

4-Aminobenzoic Acid↗
PubMed2003

Determination of total folate in plant material by chemical conversion into para-aminobenzoic acid followed by high performance liquid chromatography combined with on-line postcolumn derivatization and fluorescence detection.

A procedure involving chemical conversion of all forms of folate present in plant material into para-aminobenzoic acid (PABA) and a liquid chromatographic-fluorimetric determination with on-line postcolumn derivatization is reported. All folates are cleaved with liberation of PABA by hydrogen peroxide followed by acid hydrolysis using concentrated hydrochloric acid (37%) at 110 degrees C for 6 h. The reaction yield for individual folates conversion to PABA ranged from 44.4 to 97.3%. PABA could be determined sensitively by on-line postcolumn derivatization with fluorescamine, the detection limit for PABA being 3.02 nM. On the basis of this principle, a method for the determination of total folate in plant material, including a purification step on an affinity column, is presented, which offers a sufficient sensitivity and selectivity for routine analysis of total folate in natural samples. The total folate contents of tomatoes, carrots, white cabbage, and spinach were determined, and the results were quite comparable to the data reported. The recovery of PABA and the comparison of total folate analysis in spinach on different occasions (over 6 months) are also reported. The method is reliable, universal for all folates, including polyglutamate and monoglutamate forms, and eliminates the need for a deconjugation step and multiple conversion reactions.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Chemical and biological properties of a new cis-diammineplatinum (II) complex containing para-aminobenzoic acid as amino ligand.

In this paper we report on the synthesis, characterization and preliminary pharmacological evaluation of a new platinum (II) complex obtained by reaction of cis-diamminedichloroplatinum(II) (DDP) with para-aminobenzoic acid (PABA). The structure of this platinum compound was defined by UV, IR, 1H-NMR and elemental analysis. DPAB tested in vitro and in vivo against P388 leukemic cells displayed good antiproliferative (IC50 values after 48 h exposure of cells = 3 micrograms/ml) and antitumor activity (T/C% = 150). This compound also possesses desirable physical properties, such as a good solubility and stability in aqueous media, and a low toxicity (LD50 > 1200 mg/kg body weight) combined with a moderate nephrotoxic activity [plasma urea nitrogen (PUN) level: 36 +/- 8(SD) mg/100 ml]. DPAB was cleared from plasma ultrafiltrate (UF-plasma) very rapidly [clearance (CL), 55.3 ml x min-1 x kg-1], showing a half-life of 13.6 min. Platinum exposure (AUC) in the kidney was 2.6 times greater than that found in UF-plasma. AUCS for liver, stomach and UF-plasma were similar, while the AUC value for the spleen was 1.7 times lower than that of UF-plasma. These preliminary results seem to hold interest for further preclinical evaluation of the biological activity of this new platinum compound.

4-Aminobenzoic Acid↗
PubMed1992

p-Aminobenzoic acid transport by normal and Plasmodium falciparum-infected erythrocytes.

De novo folate biosynthesis is required for the growth of malarial parasites and is inhibited by several important antimalarial agents. We show here that exogenous p-aminobenzoic acid (pABA) can be utilized by malaria parasites to synthesize folates. The transport of pABA into parasite infected red cells was therefore characterized. Normal red cells transport pABA in a saturable and energy-dependent manner, with a dissociation constant of 83 nM. pABA transport in parasite-infected red cells may use the same mechanism, as demonstrated by similarities in time course, concentration-response, and dissociation constant (111 nM). The transport capacity of red cells is temperature-, energy- and pH-dependent. It is inhibited by the proton ionophore, carbonylcyanide m-chlorophenylhydrazone (CCCP), but not by the sodium ionophores nigericin and monensin. p-Aminosalicylic acid (PAS) inhibits pABA transport competitively, with a inhibition constant of 378 nM. Phloritin, flufanamic acid, and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DITS), which are inhibitors of the anion transporter (band 3), and oxalic acid, a substrate of this transporter, partially inhibit pABA transport into both normal and infected red cells. Interestingly, in both normal and infected red cells, the inhibitory effects of PAS and the anion transport inhibitors are additive, suggesting the involvement of 2 independent mechanisms.

4-Aminobenzoic Acid↗