scholarly journals Chemical preservatives in foodstuffs. III Hexamethylenetetramine as mold inhibitor and the antagonistic action of amino acids

1959 ◽  
Vol 31 (1) ◽  
pp. 162-173
Author(s):  
Reino R. Linko ◽  
Olavi E. Nikkilä
Keyword(s):  
Amino Acids ◽  
Inhibitory Action ◽  
Chemical Interaction ◽  
Culture Media ◽  
Inhibitory Effect ◽  
Antagonistic Effect ◽  
Antagonistic Action ◽  
Rate Of Oxygen Consumption ◽  
Chemical Preservatives ◽  
Sulphydryl Compounds

Growth and respiration tests carried out on Aspergillus, Cladosporium and Penicillium molds have shown that certain amino acids such as 1-tryptophan and 1-cysteine and certain sulphydryl compounds such as glutathione and thioglycollic acid counteract the inhibitory action of hexamethylenetetramine. In the absence of hexamethylenetetramine, these compounds inhibit the growth of the molds. The dependence of the antagonistic action on the amino acid concentration differed for 1-cysteine and 1-tryptophan. The respiration of the mold was a maximum when equimolar concentrations of 1-cysteine and of the formaldehyde formed by the decomposition of hexamethylenetetramine were present in the culture media. The antagonistic effect of 1-tryptophan increased continuously with increasing concentration until the rate of oxygen consumption was the same as in the control test with no hexamethylenetetramine or antagonist present. The antagonistic effect of these four compounds on hexamethylenetetramine or on formaldehyde is evidently due to chemical interaction. The inhibitory effect of hexamethylenetetramine on the microbial cell may at least partly be due to its ability to inactivate enzymes such as the dehydrogenases.

Effect of amino acids on thaxtomin A biosynthesis by Streptomyces scabies

2002 ◽  
Vol 48 (4) ◽  
pp. 359-364 ◽  
Author(s):  
Annie Lauzier ◽  
Claudia Goyer ◽  
Luc Ruest ◽  
Ryszard Brzezinski ◽  
Don L Crawford ◽  
...  
Keyword(s):  
Amino Acids ◽  
Inhibitory Action ◽  
Common Scab ◽  
Aromatic Amino Acids ◽  
Inhibitory Effect ◽  
Nitroaromatic Compounds ◽  
Streptomyces Scabies ◽  
Regulatory Effect ◽  
Thaxtomin A ◽  
Metabolic Precursors

The regulatory effect of amino acids on the production of thaxtomin A, a phytotoxin produced by Streptomyces scabies, was investigated. Tryptophan had an important inhibitory effect on the toxin biosynthesis in all five strains of S. scabies tested. Two other aromatic amino acids (tyrosine and phenylalanine) also inhibited thaxtomin A biosynthesis, while aliphatic amino acids did not cause an important decline in thaxtomin A production. Methylation of tryptophan prevented or reduced the inhibitory effect on thaxtomin A biosynthesis. In spite of the inhibitory action of tryptophan and phenylalanine on thaxtomin A production, incorporation of these radiolabeled molecules into thaxtomin A confirmed that they are metabolic precursors for the biosynthesis of the phytotoxin.Key words: thaxtomin A, phytotoxin, Streptomyces scabies, common scab, nitroaromatic compounds, amino acids.

Inhibition of ADP-Induced Responses in Human Platelets by Agents Elevating the Cyclic AMP Level: Comparison of Aggregation and Shape Change

1984 ◽  
Vol 52 (03) ◽  
pp. 333-335 ◽  
Author(s):  
Vider M Steen ◽  
Holm Holmsen
Keyword(s):  
Inhibitory Action ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Inhibitory Effects ◽  
Early Step ◽  
Stimulus Response ◽  
Sequential Relationship

SummaryThe inhibitory effect of cAMP-elevating agents on shape change and aggregation in human platelets was studied to improve the understanding of the sequential relationship between these two responses.Human platelet-rich plasma was preincubated for 2 min at 37° C with prostaglandin E1 or adenosine, agents known to elevate the intracellular level of cAMP. Their inhibitory effects on ADP-induced shape change and aggregation were determined both separately and simultaneously. The dose-inhibition patterns for shape change and aggregation were similar for both PGE1 and adenosine. There was no distinct difference between the inhibitory action of these two inhibitors.These observations suggest that elevation of the intracellular concentration of cAMP interferes with an early step in the stimulus-response coupling that is common for aggregation and shape change.

Mechanism of the Antiplatelet Action of Dipyridamole in Whole Blood: Modulation of Adenosine Concentration and Activity

1986 ◽  
Vol 55 (01) ◽  
pp. 012-018 ◽  
Author(s):  
Paolo Gresele ◽  
Jef Arnout ◽  
Hans Deckmyn ◽  
Jos Vermylen
Keyword(s):  
Platelet Aggregation ◽  
Adenosine Receptor ◽  
Whole Blood ◽  
Blood Cells ◽  
Inhibitory Action ◽  
Phosphodiesterase Inhibitor ◽  
Inhibitory Effect ◽  
Adenosine Concentration ◽  
Pharmacological Studies

SummaryDipyridamole inhibits platelet aggregation in whole blood at lower concentrations than in plasma. The blood cells responsible for increased effectiveness in blood are the erythrocytes. Using the impedance aggregometer we have carried out a series of pharmacological studies in vitro to elucidate the mechanism of action of dipyridamole in whole blood. Adenosine deaminase, an enzyme breaking down adenosine, reverses the inhibitory action of dipyridamole. Two different adenosine receptor antagonists, 5’-deoxy-5’-methylthioadenosine and theophylline, also partially neutralize the activity of dipyridamole in blood. Enprofylline, a phosphodiesterase inhibitor with almost no adenosine receptor antagonistic properties, potentiates the inhibition of platelet aggregation by dipyridamole. An inhibitory effect similar to that of dipyridamole can be obtained combining a pure adenosine uptake inhibitor (RE 102 BS) with a pure phosphodiesterase inhibitor (MX-MB 82 or enprofylline). Mixing the blood during preincubation with dipyridamole increases the degree of inhibition. Lowering the haematocrit slightly reduces the effectiveness.Although we did not carry out direct measurements of adenosine levels, the results of our pharmacological studies clearly show that dipyridamole inhibits platelet aggregation in whole blood by blocking the reuptake of adenosine formed from precursors released by red blood cells following microtrauma. Its slight phosphodiesterase inhibitory action potentiates the effects of adenosine on platelets.

PROTECTIVE EFFECT OF POLYPEPTIDE AND AMINO ACIDS ON THE DEVELOPMENT OF THE NERVOUS TISSUE CULTURE IN THE PRESENCE OF CYCLOPHOSPHAMIDE

2017 ◽  
pp. 22-26
Author(s):  
V. B. Dolgo-Saburov ◽  
N. I. Chalisova ◽  
L. V. Lyanginen ◽  
E. S. Zalomaeva
Keyword(s):  
Amino Acids ◽  
Cell Proliferation ◽  
Tissue Culture ◽  
Protective Effect ◽  
Organotypic Culture ◽  
Inhibitory Effect ◽  
Mustard Gas ◽  
Synthesis Inhibitor ◽  
Combined Administration ◽  
The Central Nervous System

In an organotypic culture, an investigation was conducted into combined effects of cyclophosphamide DNA as synthesis inhibitor used to model a resorptive action of mustard gas, and cortexin polypeptide or each of 20 encoded amino acids on the development of cell proliferation in cerebral cortex explants of the rat. The combined administration of cyclophosphamide together with cortexin or with each of the 20 encoded amino acids, except glycine, showed suppression of the cytostatic agent inhibitory effect. Thus, cortexin and amino acids have a protective effect on cell proliferation in the tissue culture of the central nervous system under the action of mustardlike substances.

Protective influence of coded amino acids on the development of liver tissue culture in the presence of cytostatic

2020 ◽  
pp. 48-53
Author(s):  
N. I. Chalisova ◽  
V. K. Kozlov ◽  
A. B. Mulik ◽  
E. P. Zatsepin ◽  
T. A. Kostrova
Keyword(s):  
Amino Acids ◽  
Tissue Culture ◽  
Side Effects ◽  
Liver Tissue ◽  
Organotypic Culture ◽  
Growth Zone ◽  
Inhibitory Effect ◽  
Cytostatic Drugs ◽  
Urgent Problem ◽  
Combined Exposure

An urgent problem is the search for substances that can provide a protective effect in cases of DNA synthesis and repair disorders that arise as a result of side effects of cytostatic drugs used in the treatment of cancer. The aim of this work was to study the effect of 20 encoded amino acids in the presence of Cyclophosphane on the development of organotypic culture of rat liver tissue. The results obtained indicate that Cyclophosphane; which simulates the action of such cytostatic substances; inhibits cell proliferation in the liver tissue. It was also found that the encoded amino acids: asparagine; arginine; and glutamic acid; eliminate the inhibitory effect of Cyclophosphane in liver tissue culture. The growth zone of explants after combined exposure to Cyclophosphane (whose isolated action suppressed the growth zone) and these amino acids increased significantly and reached control values. Thus; the experimental data create the basis for the development of methods for the therapeutic use of the three studied amino acids for the removal of side effects in the treatment with cytostatic drugs.

POSSIBLE ROLE OF 5α-ANDROSTANE-3α,17β-DIOL IN THE CONTROL OF FOLLICLE-STIMULATING HORMONE SECRETION IN THE IMMATURE FEMALE RAT

1982 ◽  
Vol 92 (1) ◽  
pp. 37-42 ◽  
Author(s):  
H. M. A. MEIJS-ROELOFS ◽  
P. KRAMER ◽  
L. GRIBLING-HEGGE
Keyword(s):  
Inhibitory Action ◽  
Combined Treatment ◽  
Hormone Secretion ◽  
Inhibitory Effect ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Immature Rat ◽  
Rat Strain ◽  
Intact Rats

A possible role of 5α-androstane-3α,17β-diol (3α-androstanediol) in the control of FSH secretion was studied at various ages in ovariectomized rats. In the rat strain used, vaginal opening, coincident with first ovulation, generally occurs between 37 and 42 days of age. If 3α-androstanediol alone was given as an ovarian substitute, an inhibitory effect on FSH release was evident with all three doses tested (50, 100, 300 μg/100 g body wt) between 13 and 30 days of age; at 33–35 days of age only the 300 μg dose caused some inhibition of FSH release. Results were more complex if 3α-androstanediol was given in combined treatment with oestradiol and progesterone. Given with progesterone, 3α-androstanediol showed a synergistic inhibitory action on FSH release between 20 and 30 days of age. However, when 3α-androstanediol was combined with oestradiol a clear decrease in effect, as compared to the effect of oestradiol alone, was found between 20 and 30 days of age. Also the effect of combined oestradiol and progesterone treatment was greater than the effect of combined treatment with oestradiol, progesterone and 3α-androstanediol. At all ages after day 20 none of the steroid combinations tested was capable of maintaining FSH levels in ovariectomized rats similar to those in intact rats. It is concluded that 3α-androstanediol might play a role in the control of FSH secretion in the immature rat, but after day 20 the potentially inhibitory action of 3α-androstanediol on FSH secretion is limited in the presence of oestradiol.

Amino Acid Transport in a Water-mould: The Possible Regulatory Roles of Calcium and N6-(Δ2-isopentenyl)adenine

1975 ◽  
Vol 53 (9) ◽  
pp. 975-988 ◽  
Author(s):  
Danny P. Singh ◽  
Hérb. B. LéJohn
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Osmotic Shock ◽  
Inhibitory Effect ◽  
Transport Systems ◽  
Acid Transport ◽  
Isopentenyl Adenine ◽  
Energy Dependent ◽  
Water Mould

Transport of amino acids in the water-mould Achlya is an energy-dependent process. Based on competition kinetics and studies involving the influence of pH and temperature on the initial transport rates, it was concluded that the 20 amino acids (L-isomers) commonly found in proteins were transported by more than one, possibly nine, uptake systems. This is similar to the pattern elucidated for some bacteria but unlike those uncovered for all fungi studied to date. The nine different transport systems elucidated are: (i) methionine, (ii) cysteine, (iii) proline, (iv) serine–threonine, (v) aspartic and glutamic acids, (vi) glutamine and asparagine, (vii) glycine and alanine, (viii) histidine, lysine, and arginine, and (ix) phenylalanine–tyrosine–tryptophan and leucine–isoleucine–valine as two overlapping groups. Transport of all of these amino acids was inhibited by azide, cyanide, and its derivatives and 2,4-dinitrophenol. These agents normally interfere with metabolism at the level of the electron transport chain and oxidative phosphorylation. Osmotic shock treatment of the cells released, into the shock fluid, a glycopeptide that binds calcium as well as tryptophan but no other amino acid. The shocked cells are incapable of concentrating amino acids, but remain viable and reacquire this capacity when the glycopeptide is resynthesized.Calcium played more than a secondary role in the transport of the amino acids. When bound to the membrane-localized glycopeptide, it permits concentrative transport to take place. However, excess calcium can inhibit transport which can be overcome by chelating with citrate. Calculations show that the concentration of free citrate is most important. At low citrate concentrations (less than 1 mM) in the absence of exogenously supplied calcium, enhancement of amino acid transport occurs. At high concentrations (greater than 5 mM), citrate inhibits but this effect can be reversed by titrating with calcium. Evidently, the glycopeptide acts as a calcium sink to regulate the concentration of calcium made available to the cell for its membrane activities.N6-(Δ2-isopentenyl) adenine (a plant growth 'hormone') and analogues mimic the inhibitory effect of citrate and bind to the glycopeptide as well. Replot data for citrate and N6-(Δ2-isopentyl) adenine inhibition indicate that both agents have no more than one binding constant. These results implicate calcium, glycopeptide, and energy-dependent transport of solutes in some, as yet undefinable, way.

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