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PubMed1985

Further evaluation of bentiromide in the diagnosis of canine exocrine pancreatic insufficiency.

The primary objective of this study was to evaluate the accuracy of the bentiromide test in differentiating between dogs with exocrine pancreatic insufficiency (EPI) and those with primary intestinal disease (PID). A secondary objective was to correlate the results of the commonly used diagnostic techniques with the results of the bentiromide test. This test consists of the oral administration of a synthetic peptide that is cleaved only by chymotrypsin. A subsequent rise in the plasma concentration of p-aminobenzoic acid (PABA) indicates the degree of cleavage, providing an in vivo assessment of chymotrypsin activity. Fourteen dogs with EPI and five dogs with PID were categorized on the basis of clinical signs, laboratory evaluations, and histologic examination of intestinal biopsies. Six normal dogs served as controls. The bentiromide test clearly identified the dogs with EPI and distinguished them from the dogs with PID and the control dogs. The results of the bentiromide test correlated well with the results of the clinical and laboratory evaluations. On the basis of these observations and conclusions, recommendations for the pragmatic application of the bentiromide test are offered.

4-Aminobenzoic Acid↗
PubMed1990

Lipoamidase activity in human serum is due to biotinidase.

Lipoamidase, as determined by lipoyl-p-aminobenzoic acid (L-pABA) hydrolyzing activity, and biotinidase in human serum have similar pH profiles, molecular weights, thermostabilities, and are similarly inhibited by p-hydroxymercuribenzoate and not inhibited by phenylmethylsulfonylfluoride. A monospecific polyclonal antibody prepared against biotinidase immunoprecipitated greater than 95% of serum L-pABA hydrolyzing activity and an identical proportion of biotinidase activity. In addition, children with profound biotinidase deficiency (less than 10% normal serum activity) have greatly reduced levels of L-pABA hydrolyzing activity in serum (less than 15% of mean normal activity) and obligate heterozygotes have activities intermediate between that of normal and profoundly deficient individuals. These results indicate that most, if not all, of the L-pABA hydrolyzing activity in human serum is due to biotinidase. Moreover, since the Km of L-pABA hydrolysis by serum is high, it is unlikely that lipoic acid is recycled in the serum by biotinidase.

4-Aminobenzoic Acid↗
PubMed1983

Reliability of the Bz-Ty-PABA and the pancreolauryl test in the assessment of exocrine pancreatic function.

The reliability of the para-aminobenzoic acid (PABA) test (performed in the conventional manner, i.e. without control day) and of the pancreolauryl test was assayed in respect of the exocrine pancreatic capacity measured by using the secretin-caerulein test in 57 subjects, 22 of which were suffering from chronic pancreatitis. When 50 and 20% urinary excretion of the orally administered Bz-Ty-PABA and pancreolauryl, respectively, were chosen as the lower normal limits, the PABA test showed a specificity quite similar to that of the pancreolauryl test (97 and 95%, respectively) despite the lack of a control day test, but a lower sensitivity (39 vs. 83%). The association of both tests was not advantageous compared with the pancreolauryl test alone.

4-Aminobenzoic Acid↗
PubMed1979

[The specificity of peptide-PABA-test (author's transl)].

Exocrine pancreatic function was determined by oral administration of N-benzoyl-L-tyrosyl-p-aminobenzoic acid (peptic-PABA-test) in 120 controls, 74 patients with chronic pancreatitis, 35 patients with acute pancreatitis 2--6 weeks after recovery, 201 patients with a variety of gastro-intestinal diseases and in 10 patients with anorexia nervosa. In the control group, 70% +/- 18% of the oral administered dose of PABA was found within 6 hours in the urine. In contrast the group of chronic pancreatic patients excreted only 40% +/- 13% over the same period. "False negative" PABA excretion was found in 11 (9%) of the 120 persons with no pancreas disease. "False positive" PABA excretion was found in 13 (17,5%) of the 74 patients with chronic pancreatitis. The test was not influenced by age or sex. After stomach resection or cholecystectomy and in patients with ulcus duodeni, chronic hepatitis, functional diarrhea, Crohn's disease, colitis ulcerosa and acute pancreatitis 2--6 weeks after recovery the peptide-PABA-test was not distored. Diminished PABA excretion was encountered in some patients with toxic liver disease, inflammatory disease of the small intensine like M. Whipple, celiac disease and unspecific enteritis and in a few patients with cholelithiasis. Low PABA excretion was found in early all patients with partial small intestinal resection, terminal liver cirrhosis or liver metastasis with ascites and in all patients with anorexia nervosa.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Use of Ac-L-Tyr-PAB for estimating the activity of chymotrypsin in rats.

Pancreatic secretion in rats was assessed by measuring the amounts of p-aminobenzoic acid (PABH) excreted in urine after oral administration of Ac-L-Tyr-PAB, and by determination of enzyme activity in pancreas and faeces. 3 groups of 7 rats were kept on diets with casein as the main source of nitrogen without (control K0) or with two levels of trypsin inhibitor (K1 and K2). Two other groups were fed diets with 40 and 80% of casein substituted by raw soya bean protein and having trypsin inhibitor contents equivalent to those in diets K1 and K2. Urinary excretion of PABH ranged from 99 to 105% of intake and were not different between control and experimental rats. The weight of pancreas and pancreatic activities of trypsin and chymotrypsin in all experimental rats were higher than in controls. The activity of chymotrypsin in the faeces of rats of groups K1 and K2 was greater than in K0 while in groups S1 and S2 it was about five times that in groups K1 and K2. Generally, it was greater on diets with more trypsin inhibitor. The activity of trypsin in the faeces of rats K0, K1 and S1 was several times less than in K2 and S2. It has been concluded that measurement of trypsin and chymotrypsin in faeces allows to estimate differences in the secretion of pancreatic enzymes.

4-Aminobenzoic Acid↗
PubMed1976

Nutritionally defined conditions for germination of Streptomyces viridochromogenes spores.

Spores of Streptomyces viridochromogenes were removed from the surface of solid media with glass beads and suspended in a buffer-detergent solution. Addition of yeast extract and glucose resulted in rapid loss of refractility of the spores. Appearance of germ tubes followed. Germination was accompanied by a decrease in the optical density (OD) of the suspension. The OD decrease was used as an assay for germination. A defined germination medium (DGM) comprised of L-alanine, L-glutamic acid, adenosine, para-aminobenzoic acid, and calcium and magnesium ions provided a germination rate nearly equal to that of complex media. The germination rate was essentially the same if D-alanine and D-glutamate replaced the L-isomers. The optimum pH and temperature for germination were 7.0 and 35 C. Germination was absolutely dependent on the presence of CO2. Spores harvested after growth for longer periods than the usual time (10 days) became less germinable in DGM. The same was observed for spores grown at 37 C as compared with 30 C. Spores incubated in DGM for various time periods before being transferred to a buffer solution did not continue to germinate. Spores harvested after growth of eight species of Streptomyces did not show a decrease in OD when incubated in yeast extract medium. Another strain of S. viridochromogenes did exhibit an OD decrease in the medium. Comparative properties of spores of streptomycetes, fungi, and bacilli are discussed.

Adenosine↗
PubMed1996

Effect of vitamins on the aerobic degradation of 2-chlorophenol, 4-chlorophenol, and 4-chlorobiphenyl.

The effect of vitamins on the aerobic degradation and dechlorination of 2-chlorophenol and 4-chlorophenol by Pseudomonas pickettii, strain LD1, and 4-chlorobiphenyl by Pseudomonas sp. strain CPE1 was determined. These microorganisms are capable of using the target compounds as the sole carbon and energy source, but do not need vitamins to metabolize them. The addition to the culture medium of a vitamin solution containing biotin, folic acid, pyridoxine hydrochloride, riboflavin, thiamine hydrochloride, niacin, pantothenic acid, cyanocobalamin, p-aminobenzoic acid, and thioctic acid (total final concentration: < or = 600 ppb) resulted in a 7%-16% increase in the amount of target compounds degraded over the incubation period required for the concentration of the compound in the cultures to drop to approximately zero. A corresponding increase in the amount of chloride ion produced was also detected during the same period, indicating active (and often stoichiometric) dechlorination of the target compounds.

Aerobiosis↗
PubMed2005

Stability studies on some benzocycloheptane antihistaminic agents.

The photostability of selected benzocycloheptane antihistaminic agents, namely, loratadine (I), pizotifen (II), ketotifen fumarate (III) and cyproheptatidine (IV), was investigated. Both I and II were photolabile while III and IV were photostable. To perform stability studies on the photolabile compounds (I and II), specific stability-indicating high performance liquid chromatographic (HPLC) methods were established. The accuracy, precision and reliability of the developed HPLC methods for the assay of I and II in their pharmaceutical dosage forms were reported. Assay results for both drugs were within R.S.D. values <2%. The stability-indicating power of the developed methods was validated through study of UV-degraded solutions of I and II contained in quartz cells. The photostability of both drugs was studied under UV-irradiation at 254 nm. The photodegradation kinetics of both drugs, studied in different solvents, are also reported. TLC fractionation of photodegraded solutions of both drugs, revealed two fluorescent photodegradates of drug I. The use of UV-absorbers (ascorbic acid and p-aminobenzoic acid (PABA)) enhanced the photostability of both drugs possibly through a spectral-overlay effect.

Benzocycloheptenes↗
PubMed1982

Observations on the mechanism of the protective action of sunscreens.

A method is described for measuring the entrance into excised skin of ultraviolet radiation absorbing chemicals (UVRACs) following their application to the cutaneous surface in volatile, partially volatile or nonvolatile vehicles. Also a method is presented for observing changes in optical density (OD) of a sheet of stratum corneum subsequent to the application of an UVRAC and then washing it from the surface. Using these methods, p-aminobenzoic acid (PABA) and 2-ethylhexyl p-dimethyl aminobenzoate (O-PABA) have been studied. In the presence or absence of the nonvolatile vehicle, isopropyl myristate (IM), significant amounts of PABA enter the skin but almost all of the O-PABA remains on the surface. Nevertheless subsequently PABA is more easily removed by water than is O-PABA. When either UVRAC is applied to excised stratum corneum, the OD of the tissue increases immediately; only with PABA is there a further increase as it enters the skin. In vivo, delayed erythemal responses to 280-400 nm radiation of persons to whom the UVRACs are applied correlate well with the observations made on excised skin.

4-Aminobenzoic Acid↗
PubMed1991

Acetylation of serotonin in the rabbit pineal gland: an N-acetyltransferase with properties distinct from NAT1 and NAT2 is responsible.

Two rabbit arylamine N-acetyltransferases (NAT1 and NAT2, EC 2.3.1.5) have been cloned and characterized recently in this laboratory. They catalyze the acetylation of primary arylamine and hydrazine drugs and other substrates in the liver, including sulfamethazine, p-aminosalicylic acid, and p-aminobenzoic acid. In the pineal gland, serotonin is metabolized to N-acetylserotonin by an unknown N-acetyl-transferase. Similarity of the liver enzymes and the pineal gland arylalkylamine N-acetyltransferase (AA-NAT) has been suggested, because pineal gland homogenates were shown to metabolize arylamine substrates as p-phenetidine, aniline, or phenylethylamine, and liver homogenates or partially purified liver enzyme preparations catalyzed the N-acetylation of serotonin. The present study was undertaken to elucidate the possible role of NAT1 or NAT2 in serotonin acetylation in the pineal gland. We transiently expressed rNAT1 and rNAT2 genes in COS cells, studied the kinetics of the enzymes produced with various substrates, and compared these data with activities of rabbit pineal glands and livers. These enzymatic studies were complemented with western blot analysis with antibodies against NAT1 and NAT2. Cross-hybridization of rNAT1 or rNAT2 to the gene for the pineal gland AA-NAT was tested by Southern blot studies of genomic rabbit DNA. Our results indicate that although NAT1 is expressed in the pineal gland, it is not involved in the physiologically important step of N-acetylation of serotonin.

Acetylation↗
PubMed2005

Engineering of Bacillus subtilis for enhanced total synthesis of folic acid.

We investigated whether the yield of the B vitamin folic acid could be elevated in Bacillus subtilis. Strategies for increasing the folic acid yield were investigated by employing computer-aided flux analysis and mutation. Controlling the activity of the enzyme pyruvate kinase by placing it under inducible control was one strategy devised to elevate yield while insuring that a rapid growth rate results. Other single mutation strategies included amplifying the expression of the genes in the folate operon and overexpressing the Escherichia coli aroH gene, which encodes 2-dehydro-3-deoxyphosphoheptonate aldolase. The latter could conceivably elevate the abundance of the folic acid precursor, para-aminobenzoic acid. Strains that combined two or more mutations were also constructed. Overall, a strain possessing inducible pyruvate kinase, overexpressed aroH, and increased transcription and translation of genes from the folic operon exhibited the best yield. The yield was eightfold higher than that displayed by the parent B. subtilis 168 strain.

Bacillus subtilis↗
PubMed1966

Nutritional requirements for germination, outgrowth, and vegetative growth of putrefactive anaerobe 3679 in a chemically defined medium.

Fujioka, Roger S. (University of Hawaii, Honolulu), and Hilmer A. Frank. Nutritional requirements for germination, outgrowth, and vegetative growth of putrefactive anaerobe 3679 in a chemically defined medium. J. Bacteriol. 92:1515-1520. 1966.-A chemically defined medium was used to study the nutritional requirements for germination, outgrowth, and vegetative growth of putrefactive anaerobe 3679. Vegetative growth required arginine, cysteine, phenylalanine, threonine, valine, tryptophan, K(2)HPO(4), and Na(+); was markedly stimulated by isoleucine, tyrosine, nicotinic acid, and p-aminobenzoic acid; and was stimulated slightly by alanine, biotin, pyridoxamine, glucose, and salts (MgSO(4), FeSO(4), MnSO(4)). Growth occurred over an initial pH range of 6.0 to 8.2, and at incubation temperatures ranging from 20 to 45 C. No autolysis occurred during vegetative growth, although loss of motility and cell settling were observed upon prolonged incubation. Vegetative growth was inhibited completely by aerobic conditions. Completion of spore germination was inhibited at pH 4.8, outgrowth was inhibited at pH 8.5 and higher, and germination was inhibited at 9.0 and higher. Slow germination, but no outgrowth, was observed at 8 C; at 47 and 52 C, spore inocula germinated only partially. Under aerobic conditions, all inoculated spores germinated completely, and one-half of these also emerged. Alanine was considered the primary germinant in the chemically defined medium, and arginine and mineral salts (MgSO(4), FeSO(4), MnSO(4), and NaCl), as secondary germinants. During outgrowth of germinated spores, cysteine and K(+) were required for emergence, Na(+) for elongation, and arginine and valine for division of the elongated cell.

Alanine↗
PubMed1983

Effect of dietary carrageenan and pectin on the reduction of nitro-compounds by the rat caecal microflora.

Rats were fed either a basal purified diet, or that diet supplemented with 50 g/kg pectin or iota carrageenan for 50 days, and caecal microbial nitroreductase activity determined using p-nitrobenzoic acid, p-nitrophenol, 2,4-dinitrotoluene, nitrofurantoin and metronidazole as substrates. Both pectin and carrageenan increased the weight of caecal contents, and pectin also increased the number of bacteria per caecum. In contrast, carrageenan decreased the caecal bacterial population. Pectin significantly increased the rate of reduction of metronidazole and the rate of conversion of p-nitrobenzoic acid to p-aminobenzoic acid, while carrageenan significantly decreased the rate of reduction of every compound studied. The results demonstrate that microbial reduction of the nitro-group may be altered by diet, although the response found with one nitro-compound may differ from that seen with another substrate.

Animals↗
PubMed1992

Overproduction in Escherichia coli of the dehydroquinate synthase domain of the Aspergillus nidulans pentafunctional AROM protein.

The pentafunctional AROM protein of Aspergillus nidulans is encoded by the complex aromA locus and catalyses steps 2-6 in the synthesis of chorismate, the common precursor for the aromatic amino acids and p-aminobenzoic acid. DNA sequences encoding the 3-dehydroquinate synthase (DHQ synthase) and 3-dehydroquinase domains of the AROM protein have been amplified with the inclusion of a translational stop codon at the C-terminus by PCR technology. These amplified fragments of DNA have been subcloned into the prokaryotic expression vector pKK233-2 and expressed in Escherichia coli. As a result, the DHQ synthase domain is overproduced in E. coli, forming 30% of total cell protein, and can be purified to greater than 80% homogeneity by a simple two-step protocol. The 3-dehydroquinase domain is produced at a specific activity 8-fold greater than the corresponding activity encoded by the aromA gene in A. nidulans. The qutB gene of A. nidulans encoding quinate dehydrogenase has similarly been subjected to PCR amplification and expression in E. coli. The quinate dehydrogenase is not overproduced, but is active in E. coli as a shikimate dehydrogenase, as the presence of the qutB gene allows the growth of an E. coli mutant strain lacking shikimate dehydrogenase on minimal medium lacking aromatic-amino-acid supplementation.

Alcohol Oxidoreductases↗
PubMed1991

Monomorphic and polymorphic human arylamine N-acetyltransferases: a comparison of liver isozymes and expressed products of two cloned genes.

A genetic polymorphism of human liver arylamine N-acetyltransferase (NAT; EC 2.3.1.5) enzyme activity divides populations into distinguishable "slow acetylator" and "rapid acetylator" phenotypes. Two human genes, NAT1 and NAT2, encoding NAT proteins [DNA Cell Biol. 9:193-203 (1990)] were transiently expressed in cultured monkey kidney COS-1 cells, and the resulting recombinant NAT1 and NAT2 proteins were compared with N-acetyltransferase activities in human liver cytosol with respect to their stability, chromatographic behavior on anion exchange columns, electrophoretic mobility, and arylamine acceptor substrate specificity. NAT1 was far less stable in vitro than NAT2. Under conditions designed to optimize enzyme stability, anion exchange chromatography experiments revealed that enzymes corresponding to both recombinant NAT1 and NAT2 were expressed in human liver. Recombinant and human liver NAT1 enzymes showed the same characteristic selectivity (low apparent Km, high Vmax) for the "monomorphic" substrates p-aminosalicylic acid and p-aminobenzoic acid. Such substrates fail to discriminate between the acetylator phenotypes in vivo. The same criteria established that recombinant NAT2 was indistinguishable from one of two previously observed N-acetyltransferases (NAT2A and NAT2B) whose liver contents correlate with acetylator phenotype in human populations. Recombinant NAT2 and the liver NAT2 isoforms NAT2A and NAT2B selectivity N-acetylated the "polymorphic" substrates sulfamethazine and procainamide, whose disposition in vivo is affected by the acetylation polymorphism. Interestingly, the carcinogen 2-aminofluorene was very efficiently metabolized by both NAT1 and NAT2. Independent regulation of NAT1 and NAT2 genes was suggested by a lack of correlation of NAT1 and NAT2 enzyme activities in cytosols from 39 human livers. The results provide strong evidence that the NAT2 locus is the site of the human acetylation polymorphism. In addition, the use of recombinant NAT1 and NAT2 will allow us to predict whether any given arylamine will be polymorphically acetylated in humans.

Acetylation↗
PubMed1996

Simplified methods for obtaining purified oocysts from mice and for growing Cryptosporidium parvum in vitro.

Seven- to 8-day-old Arc/Swiss mice were infected with 100,000-120,000 Cryptosporidium parvum oocysts. At 8 days postinfection (PI) the jejunum, ileum, cecum, colon, and rectum were removed. Using a simple extraction procedure and purification by Ficoll gradient centrifugation, we rountinely obtained between 3-6 million and up to 15 million purified oocysts per mouse. For in vitro cultivation, purified oocysts were pretreated in a low pH (2.5-3) 0.5% trypsin solution for 20 min, resuspended in supplemented RPMI-1640 containing glucose 0.1 g (5.55 mM), sodium bicarbonate 0.3 g, bovine bile 0.02 g, folic acid 25 micrograms, 4-aminobenzoic acid 100 micrograms, calcium pantothenate 50 micrograms, ascorbic acid 875 micrograms, penicillin G 10,000 U and streptomycin 0.01 g per 100 ml, and 1% fetal bovine serum (pH 7.4 before filtration), and used to inoculate confluent monolayers of the human adenocarcinoma cell line HCT-8. Incubation was in a candle jar at 37 C. We tested numerous supplements to RPMI-1640, different pHs, and atmospheric conditions and found the parameters described above produced the greatest parasite numbers in vitro. We obtained significantly superior growth of C. parvum grown in HCT-8 cells using the conditions described above than in culture conditions described previously.

Adenocarcinoma↗
PubMed1964

UTILIZATION OF AROMATIC AMINO ACIDS BY HYDROGENOMONAS FACILIS.

DeCicco, B. T. (Rutgers, The State University, New Brunswick, N.J.), and W. W. Umbreit. Utilization of aromatic amino acids by Hydrogenomonas facilis. J. Bacteriol. 88:1590-1594. 1964.-An auxotrophic mutant of Hydrogenomonas facilis was isolated which requires tryptophan, phenylalanine, and p-aminobenzoic acid (PABA) for growth. With glucose as the main carbon and energy source, the quantitative requirements for tryptophan and PABA were at normal microgram levels, but the requirement for phenylalanine was very large and approached substrate concentrations. The large phenylalanine requirement is due to a rapid oxidation and degradation of phenylalanine by the mutant. The utilization of both phenylalanine and glucose is adaptive, and the presence of phenylalanine partially inhibits the induction of the glucose-utilizing system. Wild-type H. facilis can utilize either phenylalanine or tyrosine for growth. Tracer studies indicated that during growth on phenylalanine, the aromatic ring is opened and degraded. Wild-type cells grown on either phenylalanine or tyrosine can oxidize phenylalanine, tyrosine, or phenylpyruvate without a lag. Another inducible pathway enables H. facilis to utilize either quinate or 3,4-dihydroxybenzoate for growth, and sequential adaptation studies revealed that quinate is converted to 3,4-dihydroxybenzoate during its degradation. Mutants may be obtained which can also utilize 2,5-dihydroxybenzoate for growth.

4-Aminobenzoic Acid↗