Showing papers on "Citric acid published in 1986"
TL;DR: Ingestion of both Al(OH)3 and citric acid resulted in a more pronounced, highly significant increase in Al concentrations, to 23 (SD 2) micrograms Al/L, probably owing to formation and absorption of Al-citrate complexes.
Abstract: Ten healthy men ingested, twice daily between meals, during each of the seven-day experimental periods: (a) citric acid (as lemon juice), (b) Al(OH)3, or (c) Al(OH)3 + citric acid. Whole blood sampled after each dietary period was analyzed electrothermally after digestion with nitric acid. Moderate, but significant, increases in mean Al concentrations as compared with pretreatment values [5 (SD 3) micrograms of Al per liter] were seen after ingestion of either citric acid or Al(OH)3: 9 (SD 4) and 12 (SD 3) micrograms/L, respectively. Ingestion of both Al(OH)3 and citric acid resulted in a more pronounced, highly significant (p less than 0.001) increase in Al concentrations, to 23 (SD 2) micrograms Al/L, probably owing to formation and absorption of Al-citrate complexes.
205 citations
TL;DR: Five patients with uric acid nephrolithiasis showed different responses between sodium alkali and potassium alkali treatment, and all five patients had persistently low urinary pH and normouricosuria, and four had hyperuricemia.
197 citations
TL;DR: In this paper, the effects of four widely employed "antioxidants" on iron-mediated hydroxyl radical formation and lipid peroxidation were studied in aqueous model systems.
Abstract: The effects of four widely employed “antioxidants” on iron-mediated hydroxyl radical formation and lipid peroxidation were studied in aqueous model systems. Iron and copper served as catalysts for the reactions which oxidized ascorbic acid and alpha-tocopherol and reduced oxygen. Ferrous ion spontaneously reduced oxygen to O−2 (su-peroxide anion radical) which led to OH (hydroxyl radical) and H2O2 generation and lipid peroxidation. Precipitation or sequestration of iron greatly depressed these oxidative events. Complexation by EDTA and citric acid, however, formed catalytically active iron chelates. The concomitant increase in iron solubility explained the substantial enhancement of iron-driven redox reactions by EDTA and citric acid.
158 citations
TL;DR: Raised phosphoenolpyruvate carboxylase activity and simultaneous accumulation of malate in the swollen root zone point to the action of a pH stat preventing a detrimental rise in cytoplasmic pH of transfer cells during enhanced H(+) extrusion.
Abstract: A variety of red pepper (Capsicum annuum L., cv Yaglik) responds to Fe deficiency stress with simultaneously enhanced H+ extrusion, reduction of ferric ions and synthesis of malic and citric acid in a swollen subapical root zone densely covered with root hairs. It is demonstrated that these stress responses temporally coincide with the development of rhizodermal and hypodermal transfer cells in this root zone. During stress response the transfer cells show a marked autofluorescence which could arise from endogenous iron chelators of the phenolic acid type. The presence of organelle-rich cytoplasm which often exhibits rotational cytoplasmic streaming points to high physiological activity and makes these cells, with their increased plasmalemma surface, particularly well suited for the entire stress response mechanism. Since Fe stress-induced acidification is diminished by vanadate and erythrosin B, both specific inhibitors of plasmalemma ATPases, it seems reasonable to suppose that H+ pumping from transfer cells is activated by an ATPase located in their plasmamembrane. H+ extrusion is also shown to be inhibited by abscisic acid. Raised phosphoenolpyruvate carboxylase activity and simultaneous accumulation of malate in the swollen root zone point to the action of a pH stat preventing a detrimental rise in cytoplasmic pH of transfer cells during enhanced H+ extrusion. The simultaneous increase in citric acid concentration favors chelation of iron at the site of its uptake and thus ensures long distance transport to the areas of metabolic demand. A direct link between citrate accumulation and ferric ion reduction as proposed in recent literature further supports the crucial role of transfer cells in the response to Fe deficiency stress.
149 citations
TL;DR: Under stress, sucrose accumulation was observed in wilting strains (poor performers) and the most dramatic response to water stress was the accumulation of citric acid in strains T25 and T256 as compared to T185 and T466.
Abstract: Two photoperiodic cotton (Gossypium hirsutum L.) strains (T185 and T466) which had been empirically selected because of poor performance and two strains (T25 and T256) selected because of enhanced performance under field water stress were evaluated for stress-induced changes in their organic acids and carbohydrates. Profiles and quantitation of organic acids and carbohydrates from aqueous extractions of cotton leaf tissue were determined by high performance liquid chromatography. In all cases, the water-stressed plants showed two to five times greater amounts of organic acids and carbohydrates over the values determined for the irrigated samples. Under stress, sucrose accumulation was observed in wilting strains (poor performers) probably related to rate of translocation out of the leaf. The most dramatic response to water stress was the accumulation of citric acid in strains T25 and T256 as compared to T185 and T466. Citric/malic acid ratios for both the irrigated and water-stressed samples of T25 and T256 were twice those of T185 and T466.
115 citations
TL;DR: The estimated absorption of aluminium was 8 and 50 times higher when antacids were taken with orange juice or with citric acid, respectively, than when taken with water, which indicates measurable quantities of aluminium are absorbed from single oral doses of antacid.
Abstract: Ten subjects with normal renal function were given different single doses of aluminium containing antacids (1, 4, or 8 tablets). The antacid tablets (aluminium content 244 mg tablet-1) were chewed and swallowed either with water, with orange juice, or with citric acid solution. There was a marked increase in serum concentration of aluminium when the antacids was ingested with citric acid (P<0·001) or with orange juice (P<0·05). When antacids were taken with water, a slight, but significant increase in serum aluminium concentration was seen with 4, but not with 1 or with 8 tablets. Following all doses of antacid, a significant increase in 24 h urinary excretion of aluminium was seen. The estimated absorption of aluminium was 8 and 50 times higher when antacids were taken with orange juice or with citric acid, respectively, than when taken with water. Thus, measurable quantities of aluminium are absorbed from single oral doses of antacids. The absorption is substantially enhanced by concomitant ingestion of citric acid.
102 citations
Patent•
03 Jul 1986TL;DR: In this article, a method and composition for stimulating underground formations containing iron deposits is presented, which is an admixture of at least one member selected from the group consisting of gluconodeltalactone, citric acid, salts of citric acids, ethylenediaminetetraacetic acid, ammonium sulfate, nitrilotriacetic acids, ammoniosinamide acid, nitric acid and ammonium nitrate.
Abstract: A method and composition for stimulating subterranean formations containing iron deposits. The composition comprises an admixture of (i) at least one member selected from the group consisting of hydroxylamine hydrochloride, hydroxylamine hydrobromide, hydroxylamine sulfate, hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine sulfate, hydrazine monobromide, hydrazine dibromide, hydrazine monoiodide, hydrazine diiodide and hydroquinone together with (ii) at least one member selected from the group consisting of gluconodeltalactone, citric acid, salts of citric acid, ethylenediaminetetraacetic acid, salts of ethylenediamianetetraacetic acid, nitrilotriacetic acid, salts of nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, and salts of hydroxyethylethylenediaminetriacetic acid and (iii) a catalytic amount of a solubilized salt of a compound capable of providing cupric, cuprous, nickel, zinc ions or mixtures thereof. The method comprises contacting the subterranean formation in an appropriate manner with the above-described composition present in an amount sufficient to sequester iron. When the treating fluid used in stimulating the subterranean formation is substantially non-acidic, the compounds of group (ii), above, can be omitted from the above-described composition and iron still is sequestered.
86 citations
TL;DR: It is demonstrated that alkali ingestion results in significant shifts in the acid-base balance of the blood and has a small, but non-significant, effect on anaerobic power and capacity as measured in a series of 3 Wingate Anaerobic Tests.
Abstract: The effect of sodium bicarbonate and sodium citrate ingestion on cycling performance in three 30 s Wingate Anaerobic Tests separated by 6 min recovery periods has been studied using 6 male subjects. Subjects ingested either sodium bicarbonate (B), sodium bicarbonate plus sodium citrate (BC), sodium citrate (C) or sodium chloride (P) 2.5 h prior to exercise in a dose of 0.3 g kg-1 body weight. Pre-exercise blood pH was 7.44 +/- 0.06, 7.42 +/- 0.05, 7.41 +/- 0.05 and 7.38 +/- 0.04 in the C, BC, B and P conditions respectively. Mean and peak power output were significantly reduced by successive Wingate tests but not significantly affected by the treatments. Performance in the second and third tests was highest following C, BC and B ingestion. The total work done in the 3 tests was 103%, 102% and 101% of that achieved in the P condition after C, BC and B ingestion respectively. The increased alkali reserve recorded subsequent to bicarbonate and citrate treatment reduced mean post-exercise acidosis, although pH was significantly higher only in the C condition (p less than 0.05) compared to P after each exercise bout. No significant differences in plasma lactate concentration were recorded at any time. Citrate ingestion appears to be most effective in elevating blood pH and [HCO3-], and in enhancing performance in short-term intermittent exercise. This study demonstrates that alkali ingestion results in significant shifts in the acid-base balance of the blood and has a small, but non-significant, effect on anaerobic power and capacity as measured in a series of 3 Wingate Anaerobic Tests.
81 citations
TL;DR: Physicochemical and clinical evidence is provided for the utility of potassium citrate in the management of hyperuricosuric calcium oxalate nephrolithiasis and the amount of undissociated uric acid and saturation of monosodium urate decline.
Abstract: Calcium stone (renal) formation In patients with hyperuricosuria has been ascribed to the urate-induced crystallization of calcium oxalate. Citrate (0.5mM), added to synthetic medium metastably supersaturated with respect to calcium oxalate, was shown to inhibit heterogeneous nucleation of calcium oxalate by monosodium urate (2 mg/mL). Long-term trial with potassium citrate (60 to 80 mEq/day) was therefore undertaken to determine whether induced hypercitraturia would prevent calcium oxalate stone formation in 19 patients with hyperuricosuria. The treatment produced a sustained rise in urinary pH by 0.55 to 0.85 to the high normal range (6.5 to 7.0). Urinary citrate levels rose by 249 to 402 mg/day to approximate the normal mean value of 643 mg/day. Commensurate with these changes, urinary saturation of calcium oxalate (relative saturation ratio) and the amount of undissociated uric acid declined significantly. However, the urinary uric acid and saturation of monosodium urate remained elevated. Stone formation declined from 1.55± ±2.70 per patient-year to 0.38 ±1.22 per patient-year during mean treatment period of 2.35 ±0.88 years. Stones ceased to form in 16 of 19 patients during treatment. The results provide physicochemical and clinical evidence for the utility of potassium citrate in the management of hyperuricosuric calcium oxalate nephrolithiasis. (Arch Intern Med1986;146:863-867)
78 citations
TL;DR: In this article, the authors evaluated the intensity of astringency in model solutions and wines varying in total acid and total phenols by paired comparison by 10 trained judges, and found a negative linear relation between relative astringencies and pH at a given tannin level for both model solution and white wine.
Abstract: Intensity of astringency in model solutions and wines varying in total acid and total phenols was evaluated by paired comparisons by 10 trained judges. Model solutions consisted of tannic (500, 1000, 2000 mg litre−1) and tartaric (0, 2, 4, 6 g litre−1) acids dissolved in aqueous solutions of ethanol (120 ml litre−1) and sucrose (5 g litre−1). Wine solutions were prepared by addition of citric acid (0, 0.5, 1, 2, 3 g litre−1 as tartaric acid) to a high phenol-red wine (2645 mg litre−1 GAE) and a moderate phenol-white wine (800 mg litre−1 GAE). At all three levels of tannic acid, astringency of model solutions increased significantly (P<0.001) with tartaric acid concentration. Astringency of white wine also increased significantly (P<0.05) with citric acid concentration. A negative linear relation was found between relative astringency and pH at a given tannin level for both model solutions and white wine. As pH was reduced, more phenolic molecules were in the phenol form thereby increasing the likelihood of hydrogen bonding between hydroxyl groups of wine tannins and ketoimide groups of mouth proteins. The preliminary hypothesis that hydrogen bonding is the main reaction involved in the formation of protein-tannin complexes resulting in the sensation of astringency was reinforced.
77 citations
TL;DR: In this article, a chemically defined medium under anerobic conditions Lactobacillus plantarum grew on glucose, but was unable to grow with mannitol as the carbon source.
01 Jun 1986
TL;DR: In this article, a solid state fermentation process was described for the production of citric acid from apple pomace by Aspergillus niger NRRL 567, which yielded as much as 90 g citric acids/kg apple pOMace fermented in the presence of 3-4% methanol at 30°C in five days.
Abstract: A solid state fermentation process is described for the production of citric acid from apple pomace byAspergillus niger NRRL 567. The yields of citric acid varied with the pomace varieties, and were dependent on (1) the amount of methanol present in the pomace, and (2) the fermentation time and temperature. The process yielded as much as 90 g citric acid/kg apple pomace fermented in the presence of 3–4% methanol at 30°C in five days.
TL;DR: It is concluded that under physiological conditions, where the Mg2+ content is around 10 mM, the observed inhibition by ATP or citrate is of poor regulatory significance.
Abstract: NADP-specific isocitrate dehydrogenase [threo-DS-isocitrate: NADP+ oxidoreductase (decarboxylating), EC 1.1.1.42] was purified 200-300-fold from the citric acid-accumulating fungus Aspergillus niger. The enzyme consists of a single polypeptide chain with a molecular mass of 60 +/- 4 kDa and has a pI of 5.9 +/- 0.2. Only a single enzyme protein was found, although the enzyme appears to occur both in the mitochondrion and in the cytoplasm. Growth on organic acids as carbon sources or on NO3- as nitrogen source led to increased activities, whereas the presence of amino acids led to lower activities. The enzyme exhibits hyperbolic kinetics with respect to its substrates isocitrate and NADP+. Mn2+ and Mg2+ are obligatory for enzyme activity. The enzyme is inhibited by its products alpha-oxoglutarate and NADPH. Among various metabolites, ATP and citrate appear to inhibit the enzyme at a concentration considered to occur intracellularly. In both cases, however, the mechanism is a removal of the metal ion cofactor from the substrates. It is concluded that under physiological conditions, where the Mg2+ content is around 10 mM, the observed inhibition by ATP or citrate is of poor regulatory significance.
TL;DR: In strictly anaerobic conditions in a culture medium adjusted to pH 5.2 with HCl and incubated at 30 degrees C, inocula containing less than 10 vegetative bacteria of Clostridium botulinum ZK3 (type A) multiplied to give greater than 10(8) bacteria per ml in 3 d.
Abstract: In strictly anaerobic conditions in a culture medium adjusted to pH 5.2 with HCl and incubated at 30 degrees C, inocula containing less than 10 vegetative bacteria of Clostridium botulinum ZK3 (type A) multiplied to give greater than 10(8) bacteria per ml in 3 d. Growth from an inoculum of between 10 and 100 spores occurred after a delay of 10-20 weeks. Citric acid concentrations of 10-50 mmol/l at pH 5.2 inhibited growth from both vegetative bacteria and spore inocula, a concentration of 50 mmol/l increasing the number of vegetative bacteria or of spores required to produce growth by a factor of approximately 10(6). The citric acid also reduced the concentration of free Ca2+ in the medium. The inhibitory effect of citric acid on vegetative bacteria at pH 5.2 could be prevented by the addition of Ca2+ or Mg2+ and greatly reduced by Fe2+ and Mn2+. The addition of Ca2+, but not of the remaining divalent metal ions, restored the concentration of free Ca2+ in the medium to that in the citrate-free medium. The inhibitory effect of citric acid on growth from a spore inoculum was only partially prevented by Ca2+. Citric acid (50 mmol/l) did not inhibit growth of strain ZK3 at pH 6 despite the greater chelating activity of citrate at pH 6 than at pH 5.2. The effect of citric acid and Ca2+ at pH 5.2 on vegetative bacteria of strains VL1 (type A) and 2346 and B6 (proteolytic type B) was similar to that on strain ZK3.
TL;DR: Testing revealed that citric acid does demonstrate antimicrobial properties, but that it is not as effective an antimicrobial agent as 5.25^ NaOCl.
TL;DR: Results show that sodium citrate promotes bladder carcinogenesis and enhancement of tumorigenesis by Sodium citrate was associated with changes in a number of urinary parameters.
Abstract: Dietary administration of 5% sodium citrate to male F344 rats clearly promoted the induction of preneoplastic and neoplastic lesions of the bladder initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine. Enhancement of tumorigenesis by sodium citrate was associated with changes in a number of urinary parameters: apparent elevation of pH; increase of sodium ion concentration; increase of crystalline MgNH4PO4. These results show that sodium citrate promotes bladder carcinogenesis.
TL;DR: Under conditions of cell recycle, cell concentration and rate of acid production were constant over 200 hours of operation, and under conditions of nitrogen limited, stability of citric acid synthesis and excretion was constant over a period of 700 hours.
Abstract: An aerobic continuous stirred tank bioreactor with cell recycle was used to produce citric acid from glucose with a yeastSaccharomycopsis lipolytica NRRL Y7576. Specific rate of total acid production was 0.045h−1, yield on glucose was 0.86 g/g and volumetric productivity was 1.16 g acid/Lh; all higher than or similar to batch values. Effluent acid concentration was 75g/L. In batch, under nitrogen limited. conditions, stability of citric acid synthesis and excretion was constant over a period of 700 hours. Under conditions of cell recycle, cell concentration and rate of acid production were constant over 200 hours of operation.
TL;DR: It is suggested that the presence of methanol may increase the permeability of the cell to citrate, and the cell responds to the diminished intracellular level by increasing production via repression of 2-oxoglutarate dehydrogenase.
Abstract: The effect of methanol on the ability of several strains of Aspergillus to produce citric acid from galactose has been investigated. In the absence of methanol, very little production (less than 1 g/l) was observed. In the presence of methanol (final concentration 1% v/v), however, citric acid production and yeilds were increased considerably. Strong relationships were observed between citric acid production and the activities of the enzymes 2-oxoglutarate dehydrogenase and pyruvate carboxylase in cell-free extracts. During citric acid production, in the presence of methanol, the activity of 2-oxoglutarate dehydrogenase was low and that of pyruvate carboxylase high. In the absence of methanol, where little citric acid was produced, the reverse was true. It is suggested that the presence of methanol may increase the permeability of the cell to citrate, and the cell responds to the diminished intracellular level by increasing production via repression of 2-oxoglutarate dehydrogenase.
Patent•
04 Jun 1986
TL;DR: In this article, an anti-inflammatory analgesic adhesive preparation is disclosed, comprising a flexible support having laminated thereon a pressure-sensitive adhesive material layer which contains Diclofenac Sodium and an organic acid such as citric acid.
Abstract: An anti-inflammatory analgesic adhesive preparation is disclosed, comprising a flexible support having laminated thereon a pressure-sensitive adhesive material layer which contains Diclofenac Sodium and an organic acid such as citric acid. This adhesive preparation has excellent percutaneous absorption properties.
TL;DR: In this article, a number of sequestering agents (ortho-and polyphosphates, citric acid, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acids (DTPA), salicylic acid, the sodium salts of oxalic, phytic and lactic acids, glycine, cysteine, 8-hydroxy-quinoline and catechol) were added to ground pork prior to cooking.
TL;DR: The results suggest that citric acid-demineralized dentin induces chondrogenesis and osteogenesis when implanted in muscle, but does so less effectively than does HCl-deminered dentin, and only within the confines of a microenvironment.
Abstract: The capacity of a roll of dentin demineralized by either 0.6N HCl, pH 1 for 3 minutes or 3 hours, or by 3M (9N) citric acid, pH 1, for 3 minutes, to induce cartilage and bone when implanted in muscle, was investigated. Serial sections of specimens were examined 7, 10, 14. 17, and 21 days after implantation, and randomly selected sections analyzed histomorphometrically. Cartilage was induced on the internal aspect of the citric acid-demineralized dentin roll, but significantly less than that induced after demineralization with HCl. The quantity of bone deposited subsequently did not significantly exceed the amount of cartilage that preceded it in relation to any of the preparations used. The results suggest that citric acid-demineralized dentin induces chondrogenesis and osteogenesis when implanted in muscle, but does so less effectively than does HCl-demineralized dentin, and only within the confines of a microenvironment. It is therefore unlikely that citric acid demineralization of root surface results in induction of cementum by this mechanism.
TL;DR: In this paper, the authors investigated the use of spent grain liquor and lager tank sediment as fermentation media for the production of citric acid by various Aspergillus niger strains.
Abstract: The possible use of spent grain liquor and lager tank sediment as fermentation media for the production of citric acid by various Aspergillus niger strains has been investigated. A strain of A. niger ATCC 9142, on spent grain liquor, gave a citric acid concentration of 19 g/L, representing a yield of 78.5% (w/w) based on total reducing sugars consumed. On lager tank sediment 11.5 g/L citric acid were produced. The yield of citric acid, based on the total reducing sugars consumed, was 57.5% (w/w).
Patent•
18 Dec 1986
TL;DR: In this paper, a neutral, noniogenic, macro-reticular, water-insoluble, crosslinked styrene-poly(vinyl)benzene and a desorbent comprising water and, optionally, acetone with the water are used to separate citric acid from a fermentation broth.
Abstract: Citric acid is separated from a fermentation broth by using an adsorbent comprising a neutral, noniogenic, macroreticular, water-insoluble, crosslinked styrene-poly(vinyl)benzene and a desorbent comprising water and, optionally, acetone with the water. The pH of the feed is adjusted and maintained below the first ionization constant (pKa 1 ) of citric acid to maintain selectivity.
Journal Article•
TL;DR: In this article, a solid state fermentation method has been developed and described for citric acid production from grape pomace by Aspergillus niger NRRL 567.
Abstract: A solid state fermentation method has been developed and is described for citric acid production from grape pomace by Aspergillus niger NRRL 567. The yields of citric acid varied with the pomace varieties and were dependent on the amount of methanol present in the pomace and the fermentation time and temperature. Under optimum fermentation conditions, this method reduced the pomace dry matter by about 43% and yielded more than 90 g of citric acid per kg of grape pomace fermented. The yield was more than 60% based on the amount of fermentable sugar consumed. These results suggest that the use of grape pomace for fungal production of citric acid could represent an efficient method of minimizing the pomace disposal problems and concomitantly producing a commercially valuable organic acid.
TL;DR: In this article, the concentrations of pyruvic acid, citric acid, L-malic acid, acetic acid, lactic acid and glycerol were determined in beers of different type and origin.
Abstract: The concentrations of pyruvic acid, citric acid, L-malic acid, acetic acid, L-lactic acid and glycerol were determined in beers of different type and origin. Large differences in organic acid and glycerol contents were found, especially between different types of beer. The amounts of acetic acid, lactic acid and glycerol can be used as process parameters. During malting a decrease of the malic acid-citric acid ratio occurred due to the pathway of the TCA-cycle. The acetic acid content and glycerol contents showed increases during fermentation. The latter parameter is useful to indicate if alcohol-free beer has been produced by fermentation. Determination of apparent final attenuation degrees of worts according to the usual laboratory practice resulted in higher glycerol contents than was found for the corresponding beers, making the value of this assay questionable.
TL;DR: In this article, the sourness of six organic acids was compared by pair tests in binary acid solutions of equal pH and equal potential hydrogen ion concentration, and only one significant difference in sourness was observed; succinic acid was more sour than malic acid.
Abstract: The sourness of six organic acids was compared by pair tests in binary acid solutions of equal pH and equal potential hydrogen ion concentration. Monoprotic lactic acid was more sour than three of the four acids against which it was tasted, while triprotic citric acid was less sour than the four other acids against which it was compared. Of the diprotic acid pairs which were evaluated, only one significant difference in sourness was observed; succinic acid was more sour than malic acid. No relationship between buffer capacity or hydrophobicity and intensity of sourness was observed.
TL;DR: A change in carbohydrate metabolism from a predominantly pentose phosphate pathway to a mainly glycolytic flux was detected during the early stages of Aspergillus niger growth in a high citric acid yielding medium.
TL;DR: Mutant strains of Aspergillus niger with reduced citrate control of carbohydrate catabolism (cic mutants) grow faster than the parent strain on media containing 5% (wt/vol) citrate and show altered citrate inhibition of NADP-specific isocitrate dehydrogenase.
Abstract: Mutant strains of Aspergillus niger with reduced citrate control of carbohydrate catabolism (cic mutants) grow faster than the parent strain on media containing 5% (wt/vol) citrate. The mutants tolerated a higher intracellular citrate concentration than the parent strain. One mutant (cic-7/3) contained phosphofructokinase activity significantly less sensitive towards citrate than the enzyme from the parent strain. When this mutant was grown under citrate-accumulating conditions, acidogenesis was far less sensitive to inhibition by Mn2+ than in the parent strain. Some of the cic mutants also showed altered citrate inhibition of NADP-specific isocitrate dehydrogenase.
TL;DR: Optimization of these uniform chromatographic conditions significantly shortens the changeover time required from one assay to another, resulting in a substantial savings of time and cost to the laboratory.
Abstract: Uniform liquid-chromatographic conditions were developed such that we could quantify norepinephrine, epinephrine, normetanephrine, metanephrine, vanillylmandelic acid, and 5-hydroxyindoleacetic acid in urine by using a single mobile phase of monochloroacetic acid and citric acid, 0.1 mol/L each. All compounds were separated on a C18 column and detected electrochemically at a potential of +0.800 V. Optimization of these uniform chromatographic conditions significantly shortens the changeover time required from one assay to another, resulting in a substantial savings of time and cost to the laboratory.
TL;DR: Ripe pepino fruit (Solanum muricatum L. cv) was analysed for water, sugars, non-volatile organic acids, amino acids, starch, vitamin C, minerals and cell wall composition as mentioned in this paper.
Abstract: Ripe pepino fruit (Solanum muricatum L. cv. ‘El Camino’) were analysed for water, sugars, non-volatile organic acids, amino acids, starch, vitamin C, minerals and cell wall composition. The sugars consisted of sucrose, fructose and glucose with sucrose accounting for 50% of the total. Citric acid made up more than 90% of the non-volatile organic acids. Malic acid and traces of quinic acid were also present. Aspartic acid accounted for 70% of the total free amino acids. Cellulose, pectin and hemicellulose represented 71, 17 and 11% respectively of the cell wall polysaccharides. The vitamin Clevel was higher than normally found in most fruits, including citrus. A limited study suggested that the major change during maturation was a continuous increase in the levels of sucrose, citric acid and the dicarboxylic amino acids.