PYOCYANINE FORMATION FROM LABELLED SUBSTRATES BY PSEUDOMONAS AERUGINOSA

1957 ◽  
Vol 3 (2) ◽  
pp. 165-169 ◽  
Author(s):  
A. C. Blackwood ◽  
A. C. Neish
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Calcium Carbonate ◽  
Specific Activity ◽  
The Other ◽  
Specific Activities ◽  
Carbonate Salts ◽  
Cell Carbon

Pseudomonas aeruginosa was grown under conditions suitable for pyocyanine production in a medium containing glycerol, L-leucine, DL-alanine, calcium carbonate, salts, and small amounts of various C14-labelled substrates. A comparison of the specific activities of the cell carbon, respiratory carbon dioxide, and pyocyanine carbon showed that glycerol and dihydroxyacetone were the only substrates from which pyocyanine having a specific activity higher than the cell carbon was formed. Glucose, fructose, pyruvate, acetate, and the 13 amino acids tested were inferior in this respect. Alanine, leucine, isoleucine, and glycine were incorporated into pyocyanine more readily than the other amino acids. Phenylalanine and tyrosine, although possessing preformed rings, were poor precursors of pyocyanine and were oxidized more readily than they were assimilated. These results suggest that pyocyanine originates from trioses but gives little indication of the nature of the intermediates.

STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XXI. THE METABOLISM OF GLYCINE-2-C14

1964 ◽  
Vol 42 (9) ◽  
pp. 1293-1299 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Total Carbon ◽  
Gluten Protein ◽  
Carbon 14 ◽  
Specific Activities

Glycine-2-C14was administered to 83-day-old wheat plants. The plants were allowed to mature fully and the carbon-14 distribution was then examined. About 80% of the radioactivity injected was recovered in the upper portions of the plant, the kernels themselves containing 66%. Proteins had a higher specific activity than other kernel constituents but the starch contained about one-half the total carbon-14 of the kernels. Glycine and serine were by far the most radioactive amino acids of the gluten protein. They had specific activities of 2720 and 2900 μc/mole C respectively while alanine, histidine, methionine, glutamic acid, and proline had specific activities ranging from 150 to 300 μc/mole C. The specific activities of carbons 1 and 2 of glycine recovered from the protein were 550 and 4900 μc/mole respectively while the specific activities of carbons 1, 2, and 3 of serine were 490, 4300, and 3100 μc/mole respectively. The results confirm previous views regarding extensive interconversion of glycine and serine in maturing wheat. Extensive labelling in carbon 3 of serine is interpreted as evidence that glycine is degraded to "active formaldehyde" and carbon dioxide.

THE ESTIMATION OF FREE AMINO ACIDS USING A MICRODIFFUSION TECHNIQUE

1952 ◽  
Vol 30 (7) ◽  
pp. 522-528 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
The Other ◽  
Routine Analysis ◽  
Average Deviation ◽  
Substantial Saving ◽  
Ionic Concentrations ◽  
The Mean

The carbon dioxide evolved when α-amino acids were heated for one hour at 85 °C. with ninhydrin was determined in a partially evacuated microdiffusion cell. Distillation of solvent from one chamber to the other was minimized by keeping the ionic concentrations of the reaction mixture and absorbing mixture approximately equal. The method was useful for samples of amino acids which liberated from 0.06 to 0.3 mgm. of carbon dioxide. The average deviation from the mean was somewhat less than 1% for samples liberating 0.2 mgm. of carbon dioxide. Use of the method for routine analysis of enzymatic digests resulted in substantial saving of time and material.

Proteinsynthese in grünen Blättern

1964 ◽  
Vol 19 (3) ◽  
pp. 235-248 ◽  
Author(s):  
Benno Parthier
Keyword(s):  
Amino Acids ◽  
Specific Activity ◽  
Subcellular Fractions ◽  
Mechanical Destruction ◽  
Cell Organization ◽  
Specific Activities ◽  
Short Time ◽  
Natural Cell

In the green leaves of Nicotiana rustica, protein synthesis of various subcellular fractions has been investigated in vivo after 14CO2-photosynthesis and also in vitro by incorporation of radioactive amino acids. Following photosynthesis, homogenization of the tissues, and differential centrifugation of the homogenates, the results show that all structural particles of the cell are able to use photosynthetically formed amino acids for the incorporation into their proteins. The proteins with the highest specific activities are found in the mitochondria-rich fractions, and with the lowest in the soluble cytoplasma supernatant. High specific activities are also observed in the ribosomal-rich fraction in short-time experiments, and also in the chloroplasts after exposure of the leaves to light. After an osmotic-mechanical destruction of the isolated 14C-labelled chloroplasts, the specific activities of lamellar proteins exceed the colourless soluble proteins of the chloroplasts. A green fraction, sedimented at 1,000 g, and perhaps mainly consisting of broken and leached chloroplasts, shows the highest specific activity of all chloroplast fractions. Obviously, due to the destruction of the natural cell organization, in vitro experiments give not only drastically decreased specific activities but also another distribution of the incorporated amino acids between the subcellular fractions, compared with experiments in vivo.

EVIDENCE FOR THE INDUCTION OF URIDINE AND DEOXY-URIDINE PHOSPHORYLASES OF REGENERATING RAT LIVER IN VITRO

1965 ◽  
Vol 43 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Esther W. Yamada
Keyword(s):  
Amino Acids ◽  
Tissue Culture ◽  
Rat Liver ◽  
Culture Medium ◽  
Specific Activity ◽  
Tissue Culture Medium ◽  
Uridine Phosphorylase ◽  
Regenerating Rat Liver ◽  
Specific Activities

Increases in the specific activities of undine and deoxyuridine phosphorylases of slices of regenerating rat liver were found 4 hours after incubation in tissue-culture medium containing uridine or 6-azauridine. These increases were not found when the tissue-culture medium contained either 8-azaguanine or puromycin, or when it lacked amino acids. Although both uridine and 6-azauridine were more effective in increasing the specific activity of uridine phosphorylase than that of deoxyuridine phosphorylase, azauridine was more effective than uridine in increasing the specific activities of both enzymes.In time studies, in which slices of regenerating rat liver were incubated in tissue-culture medium containing optimal concentrations of uridine, the specific activities of the two enzymes reached maximum levels at 3–4 hours. Puromycin prevented these increases.

scholarly journals The Reducing Property of Tobacco Smoke: 2. The Influence of Smoking Vehicle, with Particular Reference to the Pipe

1975 ◽  
Vol 8 (4) ◽  
Author(s):  
M.H. Bilimoria
Keyword(s):  
Tobacco Smoke ◽  
Specific Activity ◽  
The Other ◽  
Reducing Activity ◽  
Specific Activities

AbstractA detailed investigation of pipe smoking was undertaken to elucidate why this mode of smoking produced condensates of low dichlorophenolindophenol (DCIP)-reducing activity. Pipe tobaccos, smoked in cigarette tubes, gave reducing activities distinctly lower than those obtained for flue-cured tobacco, but the values were still higher than those obtained in pipe smoking. In pipe smoking, using both flue- and air-cured tobaccos, the initial high specific reducing activities (during 5-10 minutes of smoking) dropped to very Iow values towards the end of smoking. The decreasing specific activities paralleled the formation of water. No reducing activity was trapped by the water accumulating in the pipe, but a considerable amount of activity was trapped by the unsmoked tobacco. Unlike cigarette and cigarillo smoking, the trapped activity in cigar and pipe smoking was sufficient to significantly alter specific activity, but stilI much too Iow to obtain, in cigar and pipe smoking, the large totaI activities obtained in cigarette and cigarillo smoking. In the other three modes of smoking, viz cigarette, cigarillo and cigar, there was no change in specific activity with increase in duration of smoking (or change in butt length).

scholarly journals Incorporation of dl-[2−14C]ornithine and dl-[5−14C]arginine in milk constituents by the isolated lactating sheep udder

1968 ◽  
Vol 106 (3) ◽  
pp. 719-724 ◽  
Author(s):  
R. Verbeke ◽  
G. Peeters ◽  
Anne Marie Massart-Leën ◽  
G. Cocquyt
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Mammary Glands ◽  
Total Radioactivity ◽  
Chemical Degradation ◽  
Mammary Tissue ◽  
Specific Activities ◽  
Plasma Arginine

1. Lactating mammary glands of sheep were perfused for several hours in the presence of dl-[2−14C]ornithine or dl-[5−14C]arginine and received adequate quantities of acetate, glucose and amino acids. 2. In the [14C]ornithine experiment 1·4% of the casein and 1% of the expired carbon dioxide came from added ornithine; 96% of the total radioactivity in casein was recovered in proline; 13% of the proline of casein originated from plasma ornithine. 3. In this experiment the results of chemical degradation of proline of casein as well as relative specific activities in the isolated products are consistent with the view that ornithine is metabolized, by way of glutamic γ-semialdehyde, to proline or glutamic acid. 4. In the [14C]arginine experiments 3% of the casein and 1% of the expired carbon dioxide came from arginine; 84% of the arginine and 9% of the proline of casein originated from plasma arginine. 5. In these experiments the relative specific activities of arginine, ornithine and proline in plasma are in agreement with the view that arginine is metabolized by way of ornithine to proline. The conversion of arginine into ornithine is probably catalysed by arginase, so that arginase in mammary tissue may be involved in the process of milk synthesis.

Can a sponge fractionate isotopes?

1985 ◽  
Vol 224 (1234) ◽  
pp. 23-41 ◽  
Keyword(s):  
Stable Isotope ◽  
Nuclear Power ◽  
Sea Water ◽  
Specific Activity ◽  
The Other ◽  
Radioactive Isotopes ◽  
Specific Element ◽  
Other Hand ◽  
Specific Activities ◽  
Preferential Uptake

The study has unequivocally demonstrated that siliceous sponges Spirastrella cuspidifera and Prostylyssa foetida from the same microecological niche exhibit a high degree of species specificity, while accumulating a host of heavy metal ions (Ni, Cr, Cd, Sn, Ti, Mo, Zr). S. cuspidifera accumulated, in addition, 60 Co and 63 Ni, showing discrimination against other radionuclides, 137 Cs and 131 I, present in the ambient waters receiving controlled low level waste discharges from a B. W. R. nuclear power station. P. foetida , on the other hand, accumulated only 131 I and showed discrimination against other radionuclides including 60 Co, although the stable iodine concentrations in both the sponges were the same. The specific activity of 60 Co (in becquerels per gram of 59 Co) in S. cuspidifera and 131 I (in becquerels per gram of 127 I) in P. foetida were at least two orders of magnitude greater than in the ambient sea water. That of 63 Ni (in becquerels per gram of 62 Ni) in S. cuspidifera , on the other hand, was lower by two orders of magnitude than in either abiotic matrices from the same environment. Thus, not only did both the species show bioaccumulation of a specific element, but also preferential uptake of isotopes of the same element, though they were equally available for intake. Such differential uptake of isotopes can possibly be explained in terms of two quite different mechanisms operating, each applicable in a particular case. One is that the xenobiotic isotope enters the environment in a physicochemical form or as a complex different from that of its natural counterpart. If equilibration with the latter is slow, so that the organism acquires the xenobiotic in an unfamiliar chemical context, it may treat it as a chemically distinct entity so that its concentration factor differs from that of stable isotope, thus changing the specific activity. Alternatively, if the xenobiotic is present in the same chemical form as the stable isotope, the only way in which specific activities can be modified is by fractionation on the basis of mass of isotope. In view of the remarkable concentration factors observed for stable and radioactive isotopes of the same element and the specific activities reached, it is desirable that species of sponges, especially from the coastal and estuarine environments, be monitored to detect levels of pollution due to anthropogenic substances.

THE VALIDITY OF THE CALCULATION OF SECRETION RATES FROM THE SPECIFIC ACTIVITY OF A URINARY METABOLITE

1961 ◽  
Vol 36 (2) ◽  
pp. 265-280 ◽  
Author(s):  
K. R. Laumas ◽  
J. F.. Tait ◽  
S. A. S. Tait
Keyword(s):  
Continuous Infusion ◽  
Experimental Test ◽  
Specific Activity ◽  
Single Injection ◽  
Hormone Secretion ◽  
The Body ◽  
The Other ◽  
Urinary Metabolite ◽  
Specific Activities ◽  
Secretion Rates

ABSTRACT The validity of the calculation of secretion rates from the specific activity of a urinary metabolite after the injection of the radioactive hormone (secretion rate equals radioactivity injected divided by the specific activity of a urinary metabolite ) has been critically examined. Although in previous applications of the method the expression has been assumed to be valid on an intuitive basis, it is concluded that this is not justified unless after continuous infusion the specific activity of the hormone is constant throughout the body. In the case of a single injection, where W has been termed the single injection factor, and must be equal to one for the method to be valid. If the transport and metabolism of the hormone can be described in terms of an outer and inner pool, it has been shown that the single injection factor is nearly equal to one unless the metabolite which is analyzed is formed mostly in one pool but the overall metabolism largely occurs in the other space. Other assumptions and sources of error in the method are discussed. It is concluded that a comparison of the specific activities of various metabolites is the most generally applicable experimental test of the validity of the method. On this basis, applications of the method to obtain the secretion rates of aldosterone and cortisol seem to be justified.

scholarly journals In Vivo Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa Arising by AmpC- and Non-AmpC-Mediated Pathways

2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
Erik Skoglund ◽  
Henrietta Abodakpi ◽  
Rafael Rios ◽  
Lorena Diaz ◽  
Elsa De La Cadena ◽  
...  
Keyword(s):  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Genome Sequencing ◽  
Genetic Basis ◽  
The Other ◽  
Whole Genome ◽  
Apparent Loss ◽  
Lactamase Inhibitor ◽  
Hydrolysis Activity

Two pairs of ceftolozane/tazobactam susceptible/resistant P. aeruginosa were isolated from 2 patients after exposure to β-lactams. The genetic basis of ceftolozane/tazobactam resistance was evaluated, and β-lactam-resistant mechanisms were assessed by phenotypic assays. Whole genome sequencing identified mutations in AmpC including the mutation (V213A) and a deletion of 7 amino acids (P210–G216) in the Ω-loop. Phenotypic assays showed that ceftolozane/tazobactam resistance in the strain with AmpCV213A variant was associated with increased β-lactamase hydrolysis activity. On the other hand, the deletion of 7 amino acids in the Ω-loop of AmpC did not display enhanced β-lactamase activity. Resistance to ceftolozane/tazobactam in P. aeruginosa is associated with changes in AmpC; however, the apparent loss of β-lactamase activity in AmpC∆7 suggests that non-AmpC mechanisms could play an important role in resistance to β-lactam/β-lactamase inhibitor combinations.

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