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PubMed1984

Copper(I) transfer into apo-stellacyanin using copper(I)-thiourea as a copper-thionein model.

The direct incorporation of Cu(I) from [Cu(I)(thiourea)3]Cl, a structural analogue of Cu-thionein, into apo-stellacyanin, was successful both aerobically and anaerobically. A characteristic c.d. band of Cu(I)-stellacyanin at 270 nm (0 = -12.5 X 10(3) degrees X cm2 X dmol-1) was seen. On oxidation with hexacyanoferrate(III) or by air, the correct Cu(II) binding into the active centre of this 'Type 1' Cu-protein was deduced from chiroptical measurements which were supported by e.p.r. data. Thus Cu-thiourea turned out to be an excellent Cu(I)-donor in aqueous systems for the complete reconstitution of mononuclear Blue copper proteins.

Apoproteins↗
PubMed1987

The specificity of thiourea, dimethylthiourea and dimethyl sulphoxide as scavengers of hydroxyl radicals. Their protection of alpha 1-antiproteinase against inactivation by hypochlorous acid.

Thiourea and dimethylthiourea are powerful scavengers of hydroxyl radicals (.OH), and dimethylthiourea has been used to test the involvement of .OH in several animal models of human disease. It is shown that both thiourea and dimethylthiourea are scavengers of HOCl, a powerful oxidant produced by neutrophil myeloperoxidase. Hence the ability of dimethylthiourea to protect against neutrophil-mediated tissue damage cannot be used as evidence for a role of .OH in causing such damage. Dimethyl sulphoxide also reacts with HOCl, but at a rate that is probably too low to be biologically significant at dimethyl sulphoxide concentrations up to 10 mM. Neither mannitol nor desferrioxamine, at the concentrations normally used in radical-generating systems, appears to react with HOCl.

Deferoxamine↗
PubMedDate not supplied

Melanin-affinic thioureas as selective melanoma seekers.

2-Thiouracil and some related thioureas are receiving growing interest as selective melanoma seekers. They are incorporated into growing melanin, apparently due to covalent binding to dopaquinone, and the adduct is gradually trapped in the melanin polymer during its formation. To be clinically useful in melanoma scanning, thiouracil has been radioiodinated, and 5-iodo-2-thiouracil (ITU) was found to be localized in melanotic melanoma as selectively as thiouracil. Clinical trials with ITU, for the detection of malignant melanoma, are in progress, and the results so far are promising. Treatment with [35S]thiouracil has been performed on melanoma-bearing mice. The radiodoses needed for cure, however, were very high, which makes clinical application hazardous. Boron neutron capture therapy, on the other hand, might be a better approach. The technique is based on the irradiation of tumours with slow neutrons from an external source after the accumulation of boron in tumour tissue and clearance from normal tissues. Boron-10 undergoes instantaneous nuclear fission through the reaction 10B(n,alpha)7Li, and the emitted particles are efficient in cell killing. Boronated thioureas have been synthesized in various laboratories, and data from experiments on melanoma-bearing mice indicate that some of these compounds accumulate in the tumours in concentrations necessary for successful treatment.

Animals↗
PubMed1999

Inhibitor of HIV-1 reverse transcriptase: N'-(5-bromo-2-pyridyl)-N-[2-(2,5-dimethoxyphenyl)ethyl]thiourea.

The crystal structure of the title compound, C16H18Br-N3O2S (HI-236), a potent non-nucleoside inhibitor of HIV-1 reverse transcriptase, revealed an intramolecular hydrogen bond between a thiourea N atom and the pyridyl-N atom [N-H...N = 2.671 (3) A, graph-set motif S1(1)(6)] that imparts a more rigid conformation to the molecule. A second hydrogen bond between a thiourea N atom and the thiocarbonyl-S atom [N-H2...S = 3.403 (2) A, graph-set motif R2(2)(8)] was observed between inversion-related molecules of HI-236. The first-level hydrogen-bond graph-set notation for HI-236 was determined to be S1(1)(6)R2(2)(8).

Crystallography, X-Ray↗
PubMed2005

Modified melanocortin tetrapeptide Ac-His-dPhe-Arg-Trp-NH at the arginine side chain with ureas and thioureas.

The Ac-His-dPhe-Arg-Trp-NH2 tetrapeptide is a nonselective melanocortin agonist and replacement of Arg in the tetrapeptide with acidic, basic or neutral amino acids results in reduced potency at the melanocortin receptor (MCR) isoforms (MC1R and MC3-5R). To determine the importance of the positive charge and the guanidine moiety for melanocortin activity, a series of urea- and thiourea-substituted tetrapeptides were designed. Replacement of Arg with Lys or ornithine reduced agonist activity at the mouse mMC1 and mMC3-5 receptors, thus supporting the hypothesis that the guanidine moiety is important for receptor potency, particularly at the MC3-5 receptors. The Arg side chain-modified tetrapeptides examined in this study include substituted phenyl, naphthyl, and aliphatic urea and thiourea residues using a Lys side-chain template. These ligands elicit full-agonist pharmacology at the mouse MCRs examined in this study.

Animals↗
PubMed1991

The influence of thiourea on the development of the cultured quail embryo.

Although thyroid hormones are known to promote embryonic development, it is still questionable whether the hormones of the thyroid gland exert a stimulatory effect on the early embryo. In attempting to elucidate the thyroid function in this period, we tried to block the synthesis of thyroid hormones by thiourea and followed the embryogenesis under these conditions. The experiments were performed with cultured quail embryos (Coturnix coturnix japonica), which seemed especially suitable for those studies. The results demonstrate that thiourea causes a decrease of the survival rate, DNA-synthesis and of the excretion of uric acid into the allantoic liquid. Furthermore, it exerts an inhibitory effect on weight gain and developmental stages. On the basis of these results it seems very likely, that thyroid hormones exert a stimulatory effect on the development of quail embryos earlier than assumed previously.

Animals↗
PubMed1979

Thiourea reverses cross-links and restores biological activity in DNA treated with dichlorodiaminoplatinum (II).

Cis and trans dichlorodiaminoplatinum (II) compounds bind to DNA and form DNA cross-links, which are usually considered to be irreversible. Thiourea can reverse these cross-links without any apparent breakdown of the DNA. In addition, cis- and trans-Pt (II) treatment of lambda decreases its transfectivity. After suitable incubation with thiourea, full transfectivity of Pt(II)-treated lambda DNA can be restored.

Animals↗
PubMed2000

N-[2-(4-methylphenyl)ethyl]-N'-[2-(5-bromopyridyl)]-thiourea as a potent inhibitor of NNRTI-resistant and multidrug-resistant human immunodeficiency virus type 1.

The composite non-nucleoside reverse transcriptase inhibitor (NNRTI) binding pocket model was used to study a number of thiourea analogues with different substitutions at the 4-phenyl position including N-[2-(4-methylphenyl)ethyl]-N'-[2-(5-bromopyridyl)]-thiourea (compound HI-244), which inhibited recombinant RT better than trovirdine or compound HI-275 with an unsubstituted phenyl ring. HI-244 effectively inhibited the replication of HIV-1 strain HTLV(IIIB) in human peripheral blood mononuclear cells with an IC50 value of 0.007 microM, which is equal to the IC50 value of trovirdine. Notably, HI-244 was 20 times more effective than trovirdine against the multidrug-resistant HIV-1 strain RT-MDR with a V106A mutation (as well as additional mutations involving the RT residues 74V, 41L and 215Y) and seven times more potent than trovirdine against the NNRTI-resistant HIV-1 strain A17 with a Y181C mutation.

Anti-HIV Agents↗
PubMed2003

The thiourea group modulates the fluorescence emission decay of fluorescein-labeled molecules.

We have investigated the spectral properties and emission characteristics of fluorescein-5-thiocarbamoyl-N,N'-caproate (FITC-ACA) to examine the origin of the complex emission decay often observed in fluorescein-labeled molecules. The covalent attachment of fluorescein to epsilon-amino-n-caproic acid does not perturb the prototropic transitions of the chromophore or the general fluorescence characteristics of the various prototropic forms. However, both the monoanion and dianion forms of FITC-ACA are quenched relative to free fluorescein and exhibit a complex emission decay that is described by two discrete lifetimes. The thiourea group that links the chromophore to the caproic acid is shown to modulate the emission properties of the FITC-ACA. We show that the emission decay can also be analyzed using the asymmetric distribution model of Alcala et al. In this analysis, the tauL and tauu parameters that represent the lower and upper lifetime limits of the distribution reflect the quenched (0 ns) and unquenched lifetimes, respectively. The beta parameter that describes the distribution of lifetimes between the two limiting states can be related to the quenching efficiency of the thiourea group and to the structure and dynamics of the FITC-ACA molecule.

Fluorescein↗
PubMed1975

Novel synthesis of 2-substituted aminobenzimidazoles from thiourea derivatives.

The use of different alkyl halides as effective cyclodesulfurizing agents was thoroughly studied. N-phenyl-,N'-[o-aminophenyl]-thiourea when treated with different alkyl halides gave rise to 2-phenyl-aminobenzimidazole. The optimum conditions for such cyclodesulfurization reaction were established by using eight equivalents of the alkyl halide, ethyl alcohol as solvent, and 8 h reflux. The reaction was also successfully applied to N-o-tolyl (benzyl or n-butyl)-N'-[o-aminophenyli1-thioureas to give rise to the corresponding 2-substituted aminobenzimidazoles.

Amines↗
PubMedDate not supplied

Synthesis and antibacterial activity of pyridyl thioureas and arylthiosemicarbazones.

[N-(2-pyridyl)-N'-(4-(un) substituted] thioureas and (substitutedaryl)thiosemicarbazones were synthesised and evaluated for their antibacterial activity. All aryl thiosemicarbazones showed good activity against Aeromonas hydrophilia and Salmonella typhimurium. But none of the pyridyl thioureas showed any prominent activity against tested bacteria.

Anti-Bacterial Agents↗
PubMedDate not supplied

Radioprotective effect of novel disubstituted thioureas on pea (Pisum sativum L.) development.

The review presents our research on the influence of novel thiourea compounds on the biological and genetic effect of gamma-rays using in vivo and in vitro systems of pea. Some novel disubstituted thioureas: o-allylthioureidobenzoic acid (ATB); o-phenylthioureidobenzoic acid (PTB); N-allyl-N'-2-pyridylthiourea (A-2-PTU); N-phenyl-N'-2-pyridylthiourea (P-2-PTU) and 1,4-allylthioureidosalicylic acid (ATUS) were examined. Pea (Pisum sativum L.) seeds from five varieties were used. Experiments in vivo and in vitro were carried under laboratory, greenhouse and field conditions. The data revealed the PTB radioprotective effect demonstrated by: reduction of chromosome aberrations by 2 folds; 50% increase of germinating and surviving plants in M1; twice higher frequency of induced mutations in M2 generation relative to irradiation without PTB treatment; decreasing the level of induced radiation suppression leading to favorable effect on the initial stem and root development of pea. ATB radioprotective effect was demonstrated in vitro by: 25-35% stimulation of organogenesis; by 20-50% increase in bud formation; by 25% stimulation of growth. The effect of A-2-PTU and P-2-PTU depended on the irradiation dose. The protective effect of A-2-PTU is more pronounced at lower irradiation dose, while the effect of P-2-PTU is more pronounced at higher irradiation dose. ATUS, opposite to the other compounds, revealed radiosensibilizing effect by: 16-27% increase in lethality caused by gamma-rays leading to lower number of germinating and surviving plants in M1; 50% decrease in the number of induced mutations in M2 generation; limiting the types of induced mutations at the higher irradiation dose. As a result of the experiments useful mutation forms were obtained, characterized with: earliness, lodging and disease resistance; higher productivity.

Gamma Rays↗
PubMed2000

[Study on the stability of N-alkyl-N'-(sodium p-aminobenzenesulfonate) thiourea].

In this work, the stability of 13 kinds derivative of thiourea were studied by the UV absorption spectra and IR spectra of thiourea compounds in acidic medium at pH = 4.00, neutrality medium at pH = 7.00, basic property medium at pH = 10.00, under the influence of diffeveut store time, oxygen and sun light. Their structures were discussed and the changing rules of stability were developed.

Anti-Bacterial Agents↗
PubMed1977

Thyroid uptake or radiophosphorus as influenced by thiourea parathormone, and ACTH in Heteropneustes fossilis.

The Indian catfish, Heteropneusted fossilis, was chemically thyroidectomized with thiourea. The uptake of radioactive phosphorus by the thyroid of these thyroidectomized fished was then studied. The effect of mammalian ACTH and parathormone on the thyroid uptake of P-32 by the treated fish was also studied. It was found that thiourea reduces the P-32 uptake considerably, whereas both the hormones, separately, elevate the P-32 levels in the thyroid to near control values.

Adrenocorticotropic Hormone↗
PubMed1979

Thiourea derivatives as specific inhibitors of picorna viruses.

30 compounds with antipicorna virus activity were selected from 173 N,N'-disubstituted thiourea derivatives. The spectrum of antiviral activity was determined in vitro using entero, FMD, rhino and EMC viruses. Structure-activity relationships were studied. Several compounds produced marked activity against coxsackie viruses A and B infection of mice and FMD infection in mice and guinea pigs. N-Phenyl-N'-3-hydroxyphenyl-thiourea (PTU-23) inhibited poliovirus production by more than 99% without influencing the FL host cell. EMC virus was readily inhibited by PTU-23 in Kreb-II cells. Virus RNA synthesis was significantly reduced. Under the effect of PTU-23 the amount of 37S ssRNA extracted from EMC virus infected cells was considerably more reduced than that of the 20S ds RNA. PTU-23 did not influence the activity of virus-induced RNA polymerase in a cell-free system.

Animals↗
PubMed1975

Influence of amino acids, thiourea and hydroquinone on cellulolytic activity in some Fusarium strains.

Studies were carried out on the influence of various amino acids: cysteine, cystine, methionine, alanine, serine, tryptophan, and of thiourea and hydroquinone on the activity of cellulase synthesized by four strains of Fusarium. It follows from the results obtained that the addition of amino acids, thiourea or hydroquinone to the culture media stimulates or inhibits the activity of the enzyme studied. The effect of this action depended both on the compound and the strain studied.

Amino Acids↗
PubMed1989

Comparative studies of the effect of thiourea and BHC on behaviour and mortality in adult snails of the species Lymnaea stagnalis and on their egg masses.

When adult Lymnaea stagnalis specimens were treated with aqueous thiourea and BHC solutions for up to 30 days, they displayed hyperirritability after 3 +/- 2 days, manifested in climbing behaviour at the surface of the water to avoid contact with the treated medium and to take in fresh air. They remained clinging to the wall of the container for long intervals without feeding and their feeding rate as a whole was slow throughout the experiment. Owing to decalcification the shell became thin, fragile and semi-transparent. Egg mass production by the adults increased slightly, but there were fewer egg capsules (3-8/egg mass), indicating that the fertility rate was reduced. Mortality among the adult snails was high during prolonged treatment. The egg masses were swollen and were less sticky than in the controls. None of them survived. The effects of BHC treatment were more pronounced and faster than in thiourea treatment.

Animals↗
PubMedDate not supplied

[Permeability of the E. coli cell membrane for thiourea, dimethylsulfoxide and glycerol].

Permeability of cell envelope of Escherichia coli was investigated by the method of osmotic shock for thiourea, dimethylsulfoxide and glycerol. Characteristic times were obtained for passive permeation of these reagents. Variation of r in consequence dimethylsulfoxide less than thiourea less than glycerol was determined. The dependence of tau on the concentration of permeant reagents was observed and it was found that tau was decreased with increasing concentration of the permeant solute which was connected with the modification of the cytoplasmic membrane.

Cell Membrane↗