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Results for “Levulinic Acids”

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At least 19 recordsLinked to original sources
PubMed1979

Modulation of cytochrome biosynthesis in yeast by antimetabolite action of levulinic acid.

Levulinic acid, a competitive inhibitor of delta-aminolevulinic acid dehydratase, was used to inhibit cytochrome biosynthesis in growing yeast cells. In Saccharomyces cerevisiae the antimetabolite acts by inhibiting delta-aminolevulinic acid dehydratase in vivo, causing an accumulation of intracellular delta-aminolevulinic acid and simultaneous decreases in all classes of mitochondrial cytochromes. Changes in cellular cytochrome content with increasing levulinic acid concentration suggested the existence of different regulatory patterns in S. cerevisiae and Candida utilis. In C. utilis, cytochrome a.a3 formation is very resistant to the antimetabolite action of levulinic acid. In this aerobic yeast, cytochrome c+c1 is the most sensitive to levulinic acid, and cytochrome b exhibits intermediate sensitivity.

Candida↗
PubMed1979

Effect of levulinic acid on pigment biosynthesis in Agmenellum quadruplicatum.

When levulinic acid was added to a growing culture of the cyanobacterium (blue-green alga) Agmenellum quadruplicatum PR-6, delta-aminoelevulinic acid accumulated in the medium and chlorophyll a synthesis and cell growth were inhibited, but there was a small amount of c-phycocyanin synthesis. The amount of delta-aminolevulinic acid produced in the treated culture did not fully account for the amount of pigment synthesized in the untreated control. Levulinic acid and either sodium nitrate or ammonium chloride were added to nitrogen-starved cultures of PR-6, and delta-aminolevulinic acid production and chlorophyll a and c-phycocyanin content were monitored. When ammonium chloride was added as a nitrogen source after nitrogen starvation, the cells recovered more rapidly than when sodium nitrate was added as a nitrogen source. In cultures recovering from nitrogen starvation, synthesis of c-phycocyanin occurred before synthesis of chlorophyll a.

Aminolevulinic Acid↗
PubMed1987

A chronobiological study of delta-amino levulinic acid urinary excretion.

Determination of urinary delta-amino levulinic acid (ALA) is now systematically used in occupational health to detect an excessive exposure to lead in professionally exposed workers. However, to determine whether circadian changes of the urinary excretion of ALA alter the significance of the test, we quantified the ALA levels in the urine of 19 healthy young adults. Urine samples were taken every 3 hr between 0700 and 2300 hr and ALA levels were determined by a spectrocolorimetric method. The data indicated that the 24-hr mean ALA level was: 1.81 mg/g creatinine. The peak values (2.24 +/- 0.24) were obtained between 1400 and 1700 hr whereas the lowest ALA levels were found between 2200 and 0300 hr. Cosinor analysis revealed a significant circadian rhythm while no significant difference could be found according to sex. Possible explanations of our findings are discussed.

Adult↗
PubMed1971

Urinary delta amino levulinic acid (ALA) in the cow, dog and cat.

The level of delta amino levulinic acid (ALA) was determined in the urine of normal cows and dogs, and in the urine of dogs, cows and cats with a variety of diseases. ALA was measured in the urine of two steers and two dogs experimentally poisoned with lead. Experimental lead poisoning was followed by increased excretion of ALA in the urine. Higher levels of ALA were present in the urine of sick dogs and cats than in the urine of sick cows.

Amino Acid Metabolism, Inborn Errors↗
PubMed1988

Stimulation of Friend erythroleukemic cell cytodifferentiation by 5-amino levulinic acid; porphyrins, cell size, segregation of sialoglycoproteins, and nuclear translocation.

The late events of erythroid differentiation in Friend erythroleukemic cells (FELC), stimulated by 5-amino levulinic acid (5-ALA), were studied. Cultivation of the cells in 5-ALA-enriched media triggered a chain reaction, beginning with an immediate and rapid accumulation of endogenous porphyrins, in particular protoporphyrin and hemin. Incorporation of 14C-ALA was rapid and independent of dimethylsulfoxide (DMSO) induction. In parallel, on the second day of growth, a marked decrease in cell volume was elucidated by flow cytometry. The total protein content was reduced, while Fe uptake and hemoglobin synthesis were increased. The combination of DMSO and 5-ALA produced the most effective induction of the FELC, and the differentiation criteria were the most advanced. The cells exposed to the combined stimulation became loaded with heme and hemoglobin and their generation time was prolonged up to 35 h. Transmission electron microscopy of these treated cells showed a morphological alteration to pearlike cells, associated with a typical nuclear translocation phenomenon and a regional segregation of sialoglycoproteins. An uneven distribution of organelles was revealed; one part of the cell contained numerous ribosomes and the nucleus, while the other part was hemoglobinized, contained mitochondria, and the outer membrane was heavily labeled with ferritin hydrazide, a marker for sialoglycoproteins. The enhanced stimulation of Friend cells by 5-ALA promoted an advanced step of erythroid maturation that has much in common with the late events of normal nuclear extrusion process.

Aminolevulinic Acid↗
PubMed1976

Biosynthesis of rat kidney catalase. Double-labeling by [14C]leucine and delta-amino[3H]levulinic acid.

Kidney catalase [EC 1.11.1.6] was doubly labeled by injecting a mixture of [14C]-leucine and delta-amino[3H]levulinic acid (ALA) into normal and allyliso-(2-isopropyl-4-pentenoyl)urea (Sedormid)-treated rats. Shortly after the injection of a tracer dose or the precursors, catalase in microsomes showed the highest specific radioactivities among catalases from various cell fractions. On the other hand, peroxisomal catalase was labeled gradually, reaching a plateau at about 90 min. The patterns of incorporation of both isotopes were similar to those obtained previously with rat live catalase, except that the 3H-radioactivities were much higher. From the results obtained it could be postulated that kidney catalase is synthesized on polysomes and then transferred to peroxisomes, directly or via the soluble phase. The ratio of 3H/14C incorporated was lowest in microsomal catalase, highest in microsomal catalase, highest in peroxisomal enzyme and intermediate in catalase of the soluble fraction. The increment with time was large in the latter two catalases, while the former showed a rather small change. The evidence suggests that nascent catalase contains less heme than the completed molecule; further addition of heme to this intermediate seems to occur in the cytosol, and possibly also in peroxisomes. Administration of a porphyrinogenic drug, (2-isopropyl-4-pentenoyl)urea, produced a remarkable decrease in the incorporation of [3H]ALA into kidney catalase, with no significant effect on that of [14C]leucine.

Aminolevulinic Acid↗
PubMed1976

Heavy metal levels and delta-amino-levulinic acid dehydrase levels in peripheral polyneuropathy.

On the basis of assay of heavy metals in whole blood (lead, cadimum, chromium, copper, nickel and manganese) and delta-amino-levulinic-acid dehydrase (ALA-D) and ALA in urine in a normal Danish population, the levels of these clinco-chemical factors were assayed in 23 patients with peripheral neuropathy of unknown etiology. All patients studied showed electro-physiological sign of denervation and/or reduced motor or sensoric nerve conduction velocity. Cadmium and manganese were never found to be increased. In all but four patients, an increase of one or more heavy metals was found. Ten patients showed raised levels of two or more metals, the dominant metal being lead (10 cases), nine patients showed increased in chromium. A significant corrleation was found between increasing lead levels and decreasing ALA-D activity. Although normal concentrations of manganese were found, correlation analysis revealed a significant correlation between increased manganese and decreased ALA-D. The raised values of heavy metals could not be traced to occupational or other exposure to heavy metals and the increased values were not related to tobacco consumption. The findings are discussed in relation to known data on neuropathy and the results seem to indicate a multifactorial patholgenesis of the disease. Among factors contributing to the precipitation of the syndrome may be raised levels of heavy metals.

Adult↗
PubMed1975

Blood lead levels and erythrocyte delta-amino-levulinic acid dehydratase activity of selected population groups in Helsinki.

The levels of lead in the blood of the adult general population in Helsinki were determined during the period May 1972-June 1973. The possibility of occupational exposure to lead was scrupulously excluded.As control groups rural population groups were sampled in the commune of Pertunmaa and the communes of Haapajärvi and Pyhäjärvi. The concentrations of air-suspended particulate lead were studied during 1 year in Helsinki and Pertunmaa; the population groups were sampled from the geographical vicinity of the sampling sites. Care was taken to ensure the accuracy and precision of the analytical methods at experienced laboratories. The annual mean concentration of lead in air in Helsinki ranged from 0.43 to 1.32 mug/m3. The corresponding mean at the rural sampling site (Pertunmaa) was 0.025 mug/m3. From an international standpoint, the Pb-B levels were low. The highest mean Pb-B value in groups of the general population occurred in the rural male group (12.3 mug/100 ml); and the lowest, in the female respondents of the Pertunmaa survey (7.9 mug/100 ml). A group comprising 86 male streetsweepers from Helsinki displayed a Pb-B mean value of 13.3 mug/100 ml, and 28 traffic-directing policemen displayed a mean of 13.5 mug/100 ml, a finding indicating a slight increase in lead absorption. No effect on the Pb-B levels of traffic alone was detectalbe within the general population; thus no statistically significant differences were found between downtown and rural or suburban Pb-B levels. The observation that the Pohjois-Haaga suburbanites disclosed higher Pb-B levels. The observation that the Pohjois-Haaga suburbanites disclosed higher Pb-B levels than did other suburbanites indicates that factors other than traffic should be borne in mind in the assessment of the effect of traffic on lead absorption. The delta-amino-levulinic acid dehydratase (ALAD) assay proved useful and reliable in the discrimination between separate groups whose Pb-B levels differed to a small but measurable extent. The negative correlation between Pb-B and ALAD activity was found to prevail at a statistically significant level still at Pb-B levels of 10 mug/100 ml or lower.

Adolescent↗
PubMed1972

Comparative effect of oxygen and nitrate on protoporphyrin and heme synthesis from delta-amino levulinic acid in bacterial cultures.

Pseudomonas aeruginosa and P. denitrificans accumulate more protoheme and considerably more protoporphyrin during anaerobic growth under denitrifying conditions than during aerobic growth. In Escherichia coli, the small accumulation of protoporphyrin and protoheme which occurs during anaerobic growth is slightly stimulated by nitrate and markedly stimulated by oxygen.

Aerobiosis↗