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PubMed2002

Discrimination of the cell surface of the coccolithophorid Pleurochrysis haptonemofera from light scattering and fluorescence after fluorescein-isothiocyanate-labeled lectin staining measured by flow cytometry.

We investigated the extent of calcification on the cell surface of the coccolithophorid Pleurochrysis haptonemofera using flow cytometry. Side scattering (SSC) by coccolith-bearing cells was higher than that by naked cells, suggesting the difference was due to scattering of the laser beam by the coccoliths. SSC of coccolith-bearing cells under acidic conditions corresponded well to the extracellular Ca content, although SSC could not be used to detect a delicate change in the coccolith thickness. The increase in SSC during the reproduction of coccoliths after decalcification was consistent with the increase in the number of coccoliths on the cell surface. The fluorescence after fluorescein-isothiocyanate-labeled lectin staining suggests that alpha- d-mannose, alpha- d-glucose, d-galactose, d- N-acetylgalactosamine, or derivatives of them are included in the coccoliths. Measurement of SSC and fluorescence after fluorescein-isothiocyanate-labeled lectin staining enabled rapid and quantitative determination of the status on the cell surface and isolation of desirable cells for physiological studies by cell sorting.

Journal Article↗
PubMed1996

Inhibition of human leukaemia 60 cell growth by mercapturic acid metabolites of phenylethyl isothiocyanate.

Mercapturic acid pathway metabolites of phenylethyl isothiocyanate inhibited the growth of human leukaemia 60 (HL60) cells in vitro. The adduct with L-cysteine, S-(N-phenylethylthiocarbamoyl)cysteine, was the most potent with strong antileukaemic activity: the median growth inhibitory concentration (GC50) value was 336 +/- 1 nM (N = 18) compared with GC50 values of the precursor formed from dietary glucosinolates, phenylethyl isothiocyanate, 1.49 +/- 0.01 microM (N = 8), and the initial mercapturic acid pathway metabolite S-(N-phenylethylthiocarbamoyl)glutathione 5.46 +/- 0.36 microM (N = 18). S-(N-Benzylthiocarbamoyl)cysteine and S-(N-phenylpropylthiocarbamoyl)cysteine also had antiproliferative activity but S-(N-phenylethylthiocarbamoyl)cysteine was the most potent compound studied. The latter induced DNA fragmentation in HL60 cells but DNA laddering characteristic of apoptosis was not observed. It had low toxicity to corresponding differentiated cells, neutrophils, in culture, and therefore the cytotoxicity had selectivity for leukaemia cells. The antiproliferative activity of S-(N-phenylethylthiocarbamoyl)cysteine was lost during preincubation with culture medium, attributed to s-thiocarbamoyl transfer to serum proteins, which may decrease its effectiveness in vivo. The antiproliferative activity of S-(N-phenylalkylthiocarbamoyl)cysteine derivatives, by inhibiting tumour growth in pre-clinical development, may contribute to the association of decreased cancer incidence with dietary glucosinolate consumption.

Acetylcysteine↗
PubMed1975

The use of fluorescein isothiocyanate labelled lectins for immunohistochemical demonstration of saccharides.

Cryostat sections of various tissues from man, rat, mice, hamster, rabbit, guinea pig, sparrow and carp were examined by fluorescence microscopy after incubation with fluorescein isothiocyanate labelled Concanavalin A and Lens culinaris lectin. In the same tissue of various species no basic differences in the pattern of fluorescence were observed. In general, connective tissue structures were stained by both lectins in the same degree, whereas by fluorescein isothiocyanate labelled Concanavalin A additionally a varying staining of the cell surface and of cytoplasmic structures occurred. The results show the general presence of Concanavalin A and Lens culinaris lectin receptors in normal animal tissues.

Animals↗
PubMed2001

Exudation of low molecular weight compounds (thiobismethane, methyl isocyanide, and methyl isothiocyanate) as a possible chemical defense mechanism in the marine sponge Ircinia felix.

The volatile constituents of the marine sponge Ircinia felix were obtained by dynamic headspace extraction and analyzed by HRGC, HRGC-MS and HRGC-Odor at sniffing port. Fifty-nine volatiles were identified for the first time in the odor of this sponge. Hydrocarbons (32.9%), alcohols (17.8%) and carbonyl compounds (16.0%) predominated in the sponge volatile profile, followed by esters (11.6%), halogen compounds (8.6%), ethers (7.7%), nitrogen and/or sulfur compounds (4.6%) and carboxylic acids (0.8%). Among the identified volatiles, thiobismethane (commonly known as dimethylsulfide), methyl isocyanide and methyl isothiocyanate were found to be responsible for the nauseating and toxic smell emitted by the sponge and for the antimicrobial activity detected in the volatile extract. Exudation experiments in aquarium and in situ conditions revealed that thiobismethane, methyl isocyanide and methyl isothiocyanate are continuously released by the sponge. Upon injury, the concentration of these volatiles increased strongly. Hence, these substances form a chemical protective barrier which may help these sponges avoid fouling, compete for space, prevent infection in the short term, and/or signal generalist predators regarding the existence of other toxic substances in the internal tissues.

Journal Article↗
PubMed1998

Photosensitization of Staphylococcus aureus with malachite green isothiocyanate: inactivation efficiency and spectroscopic analysis.

The potential of malachite green isothiocyanate as a photosensitizer for the inactivation of bacteria has been evaluated. Samples of Staphylococcus aureus are treated with the dye and exposed to continuous-wave red light from a filtered xenon lamp. Reduction in cell viability is seen to increase with radiation dose, whilst non-photosensitized samples are largely unaffected with exposure. The mechanism of photosensitization and the subsequent inactivation is addressed. UV-Vis and Fourier-transform infrared absorption spectrometry have been applied to this biological system, revealing the rapid hydrolysis of the isothiocyanate group of the dye and the transition to the colourless carbinol base when in solution. On binding to Staphylococcus aureus via a complexation mechanism, the dye is seen to be stabilized in its cationic form. Involvement of the excited triplet state of the photosensitizer is suggested and identification of reduced dye photoproducts is made following irradiation.

Absorption↗
PubMed1983

Calcium ion dependent covalent modification of calmodulin with norchlorpromazine isothiocyanate.

Calmodulin forms a covalent, one to one, complex with 3H-labeled norchlorpromazine isothiocyanate. Complex formation was monitored by high-performance liquid chromatography using a CN reverse-phase column which resolves calmodulin, the calmodulin-norchlorpromazine adduct, and norchlorpromazine isothiocyanate. Formation of the adduct requires Ca2+ and is not observed with norchlorpromazine. The one to one calmodulin-norchlorpromazine complex does not activate phosphodiesterase but can interact with the enzyme and competitively inhibit its stimulation by calmodulin. High concentrations of trifluoperazine inhibit whereas low concentrations stimulate complex formation. This apparent potentiation of the interaction of calmodulin with norchlorpromazine by another phenothiazine suggests that calmodulin contains at least two phenothiazine binding sites and that the binding of phenothiazine to calmodulin is cooperative.

Animals↗
PubMed1998

Thermal Degradation of Allyl Isothiocyanate in Aqueous Solution.

Allyl isothiocyanate in an aqueous solution was heated and refluxed at 100 degrees C for 1 h. The reaction mixtures were then extracted with methylene chloride and analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The mixtures in aqueous phase were analyzed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) equipped with an atmospheric-pressure chemical ionization (APCI) interface. The compounds identified in the methylene chloride extracts included diallyl sulfide, diallyl disulfide, diallyl trisulfide, diallyl tetrasulfide, allyl thiocyanate, 3H-1,2-dithiolene, 2-vinyl-4H-1,3-dithiin, 4H-1,2,3-trithiin, and 5-methyl-1,2,3,4-tetrathiane. N,N'-Diallylthiourea, which was the major degradation product in the aqueous phase from the thermal reaction of allyl isothiocyanate, was identified by using LC-MS (APCI+), direct-probe EI-MS, and (1)H-NMR. The possible mechanism for the formation of these products was proposed.

Journal Article↗
PubMed1992

Electrophilic opioid ligands. Oxygen tethered alpha-methylene-gamma-lactone, acrylate, isothiocyanate, and epoxide derivatives of 6 beta-naltrexol.

O6-Ether derivatives of 6 beta-naltrexol in which the ether substituent includes various electrophilic groups have been synthesized in an effort to examine structure-activity requirements at the 6 beta-substituent for receptor affinity and irreversibility of binding in opioid receptor preparations. A series of tethered 6 beta-ethers having terminal epoxides, alpha-methylene-gamma-lactones, and an isothiocyanate group were prepared. The stereochemistry of the alpha-methylene-gamma-lactones was established by convergent synthesis of their reduction products from epoxides of known absolute stereochemistry. In general, the tested compounds showed comparable affinity and selectivity for the receptor subtypes. All were found with high affinity for mu-sites. The terminal epoxide ether diastereomers 8 and 9 were not bound irreversibly in the assay for total opioid receptors. The alpha-methylene-gamma-lactone diastereomers 10 and 11, and their O14-acetyl precursors 20 and 21, respectively, varied in their irreversible effects, but where noted these effects were mu-site selective. Methacrylate ether 7 and isothiocyanate ether 12 were bound irreversibly at both mu- and delta-sites.

Acrylates↗
PubMed1997

alpha-(Arylthio)imidoyl Radicals: [3 + 2] Radical Annulation of Aryl Isothiocyanates with 2-Cyano-Substituted Aryl Radicals.

A novel cascade radical reaction is described involving aryl isothiocyanates and 2-cyanoaryl radicals. The mechanism entails the formation of an alpha-(arylthio)imidoyl radical, a 5-exo-dig cyclization onto a cyano group, and a final 6-membered ring closure of an iminyl radical. The competitive 5-membered spiro-cyclization of the iminyl, leading to an isomeric product, was only observed in the case of a disubstituted aryl isothiocyanate. The whole process involves a rare example of [3 + 2] radical annulation and allows the one-pot synthesis of tetracondensed nitrogen heterocycles in good yields.

Journal Article↗
PubMed2004

Cyclometallated Pd(II) azido complexes containing 6-phenyl-2,2'-bipyridyl or 2-phenylpyridyl derivatives: synthesis and reactivity toward organic isocyanides and isothiocyanates.

Cyclometallated palladium(II) azido complexes containing C,N,N- or C,N-donor ligands, [Pd(N(3))L](HL = 6-phenyl-2,2'-bipyridine or 2-phenylpyridyl derivatives), showed different reactivities toward organic isocyanides and isothiocyanates. In particular, aryl isocyanides (CN-Ar) underwent insertion into the orthometallated Pd-C bond on the phenyl moiety of the supporting ligand (L) in [Pd(N(3))L] or [Pd(N(3))(PR(3))L] to selectively give carbodiimido [[Pd(N=C=N-Ar)L]], imidoyl [[Pd(N(3))(-C=N-Ar)(PR(3))L]], or imidoyl carbodiimido complexes [[Pd(N=C=N-Ar)(-C=N-Ar)L] or [Pd(N=C=N-Ar)(-C=N-Ar)(PR(3))L]], depending on reaction conditions. Interestingly, reactions of [Pd(N(3))(PR(3))L] with organic isothiocyanates gave unusual dinuclear complexes [(micro-SCN(4)-R)PdL](2), exhibiting the concurrent S- and N-coordinating thio-tetrazole bridge.

Journal Article↗
PubMed1979

Regional differentiation of the sperm surface as studied with 125I-diiodofluorescein isothiocyanate, an impermeant reagent that allows isolation of the labeled components.

The regional differentiation of the sperm surface has been studied with the aid of a novel covalent labeling technique that permits concurrent cytological, biochemical, and immunological analyses. For these studies isothiocyanate derivatives of fluorescein (FITC) and diiodofluorescein (IFC) were employed: the latter can be prepared with radioiodine to high specific activity (125IFC) and is an impermeant reagent for the erythrocyte surface. Sperm of sea urchin (Strongylocentrotus purpuratus), medaka )Oryzias latipes), and golden hamster bind the fluorescent chromophores with a nonuniform distribution, most of the fluorescence being associated with the midpiece. The radioactive derivative 125IFC permits an analysis of the proteins that are responsible for most of the binding. Additionally, 125 IFC-labeled sperm are capable of fertilizing eggs, as assessed by autoradiography. That IFC labels the surface of the sperm was inferred from the following: (a) the labeling of the surfaces of other cells by fluorescein isothiocyanate and its derivatives; (b) the agglutination of labeled sperm by antibodies directed against IFC; (c) the use of peroxidase-dependent immunocytochemical reaction using anti-IFC antibodies, with analysis by electron microscopy; and (d) extraction of labeled sea urchin sperm with Triton X-100 under conditions that preferentially solubilize the plasma membrane. The antiserum directed against IFC was used to isolate the labeled surface components from Triton X-100 extracts of whole sperm, by immunoprecipitation, with Staphylococcus-A protein serving as a coprecipitant. The results support previous data showing that the sperm surface is a heterogeneous mosaic of restricted domains, one notable zone being the midpiece, where common molecular properties may be shared by sperm with distinctly different morphologies. In addition, IFC-mediated covalent alteration of specific cell surface proteins may be used to label, to identify, and, with the use of anti-IFC antibodies, to isolate such proteins from other cellular constituents.

Animals↗
PubMed2005

Hydrogen sulfide protects colon cancer cells from chemopreventative agent beta-phenylethyl isothiocyanate induced apoptosis.

AIM: Hydrogen sulfide (H(2)S) is a prominent gaseous constituent of the gastrointestinal (GI) tract with known cytotoxic properties. Endogenous concentrations of H(2)S are reported to range between 0.2-3.4 mmol/L in the GI tract of mice and humans. Considering such high levels we speculate that, at non-toxic concentrations, H(2)S may interact with chemical agents and alter the response of colonic epithelium cells to such compounds. The GI tract is a major site for the absorption of phytochemical constituents such as isothiocyanates, flavonoids, and carotenoids, with each group having a role in the prevention of human diseases such as colon cancer. The chemopreventative properties of the phytochemical agent beta-phenyethyl isothiocyanate (PEITC) are well recognized. However, little is currently known about the physiological or biochemical factors present in the GI tract that may influence the biological properties of ITCs. The current study was undertaken to determine the effects of H(2)S on PEITC mediated apoptosis in colon cancer cells. METHODS: Induction of apoptosis by PEITC in human colon cancer HCT116 cells was assessed using classic apoptotic markers namely SubG1 population analysis, caspase-3 like activity and nuclear fragmentation and condensation coupled with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide) viability assay and LDH leakage. RESULTS: PEITC significantly induced apoptosis in HCT116 cells as assessed by SubG1 population formation, nuclear condensation, LDH leakage and caspase-3 activity after 24 h, these data being significant from control groups (P<0.01). In contrast, co-treatment of cells with physiological concentrations of H2S (0.1-1 mmol/L) prevented PEITC mediated apoptosis as assessed using the parameters described. CONCLUSION: PEITC effectively induced cell death in the human adenocarcinoma cell line HCT116 in vitro through classic apoptotic mechanisms. However, in the presence of H(2)S, apoptosis was abolished. These data suggest that H(2)S may play a significant role in the response of colonic epithelial cells to beneficial as well as toxic agents present within the GI tract.

Anticarcinogenic Agents↗
PubMed1976

The metabolism of L-ethionine in rats fed alpha-naphthyl isothiocyanate.

L-[ethyl-2-14C] ethionine was administered in a single dose to rats fed a diet containing 0.10% alpha-naththyl isothiocyanate for a period of time between 6 and 99 days. Ethionine metabolites excreted into urine were investigated as a function of induced pathologic changes in the liver. A short-time exposure (6 and 14 days) to alpha-naththyl isothiocyanate increased the excretion of free ethionine and S-adenosylethionine at the expense of total ethionine sulfoxide. With the extended feeding period the excretion of total ethionine sulfoxide became normalized while the excretion of free ethionine and S-adenosylethionine decreased. The acetylated fraction of ethionine sulfoxide decreased rapidly and reached a minimum in 14 days of feeding. This fraction subsequently started to increase, but did not reach the values obtained in normal rats.

1-Naphthylisothiocyanate↗
PubMed1991

Isothiocyanate derivatives of cocaine: irreversible inhibition of ligand binding at the dopamine transporter.

Isothiocyanate derivatives of (-)-cocaine were prepared and tested for inhibitory potency at the cocaine receptor in rat striatal membranes. Coincubation with m-isothiocyanatobenzoylecgonine methyl ester (m-ISOCOC), p-isothiocyanatobenzoylecgonine methyl ester (p-ISOCOC), and 3 beta-(4-isothiocyanatophenyl)tropane-2-carboxylic acid methyl ester (ISOWIN) resulted in inhibition of [3H]WIN 35,428 binding, but the compounds were about 10-fold weaker than (-)-cocaine. However, p-ISOCOC was approximately 3-fold more potent than metaphit, an isothiocyanate derivative of phencyclidine. p-ISOCOC was equipotent at the serotonin transporter but was much less potent at the norepinephrine transporter and was inactive at the D2 dopamine receptor at 1000 microM concentration. The IC50 value for m-ISOCOC and p-ISOCOC varied with tissue concentration, suggesting irreversible inhibition of binding. Preincubation with m-ISOCOC and p-ISOCOC resulted in inhibition of [3H]WIN 35,428 binding that could not be removed by washing of the membranes; in contrast, preincubation with (-)-cocaine caused inhibition that was readily removed by washing. Preincubation with 1 microM concentrations of p-ISOCOC resulted in a large reduction in Bmax of the high affinity binding site for [3H]WIN 35,428. Preincubation with 100 microM p-ISOCOC eliminated the high affinity site and apparently reduced the affinity at the low affinity site. Coincubation of 10 microM p-ISOCOC with 100 microM cocaine prevented the total loss of [3H]WIN 35,428 binding. The uptake of [3H]dopamine was inhibited by p-ISOCOC with an IC50 comparable to that of cocaine. Additionally, preincubation of rat striatal synaptosomes with 10 microM p-ISOCOC reduced the Vmax of [3H]dopamine uptake after washing. These data suggest that m-ISOCOC and p-ISOCOC are useful irreversible acylators of (-)-cocaine binding sites at the dopamine transporter.

Animals↗
PubMedDate not supplied

[Use of fluorescein isothiocyanate to label plasma membrane of lymphocytes].

The possibility of using fluoresceine isothiocyanate to label plasmatic membranes of lymphocytes was explored. Membrane labeling can be done under physiological conditions. The label interacted with the surface located membrane component, and the binding centers became saturated with the label concentration which left the membrane undamaged. Modification of the membrane surface resulting from fluoresceine isothiocyanate treatment influenced significantly intercellular interactions mediating mitogen-induced blast transformation.

Cell Membrane↗
PubMed1979

[Convalent binding of various tetra- and tricyclic heterocycles with isothiocyanate structure to human serum albumin and bovine gamma globulin. Part 24: Immunosuppressive agent - antigen conjugates (author's transl)].

In view of their potential activity as antigen-specific immunosuppressive agents, the authors produced conjugates by treating the tri- and tetracyclic compounds 1-8 (with isothiocyanate structure) with human serum albumin (HSA) and bovine gamma globulin (BGG). In certain cases the conjugates of BGG were obtained only under conditions leading to protein degeneration. The corresponding products were devoid of antigen-specific immunosuppressive activity and must be considered to be merely repository forms of the respective low-molecular compounds. In contrast, the conjugates of HSA could be obtained under conditions under which no protein denaturation was detectable. These conjugates may be used for the planned investigation. After reaction of the isothiocyanates with the proteins, time dependent changes were observed in the ultraviolet spectra of some conjugates, the possible causes of which are discussed.

Animals↗
PubMedDate not supplied

Isothiocyanato boron dipyrromethenes--the first BODIPY analogues of fluorescein isothiocyanate.

Two boron complexes of 5-phenyldipyrromethenes bearing isothiocyanate groups on the phenyl ring have been synthesized for the first time. The utility of these new fluorescence probes for labeling biologically relevant proteins is demonstrated on two monoclonal antibodies that bind to antigens overexpressed on cancer cells. Spectral comparison of the two structures reveals significant photophysical differences, including bathochromically shifted excitation and emission bands, increased molar absorptivity and a large increase in fluorescence quantum yield of approximately 10 times. Differences in photophysical parameters are linked to hindered rotation of the phenyl ring in one of the probes.

Antibodies, Monoclonal↗
PubMed1991

[Synthesis of receptor reagent--estradiol-polyethyleneglycol-fluorescein isothiocyanate].

Estradiol conjugate has been used as a tracer to detect estrogen receptor of human mammary cancer cells. In order to look for more stable carrier of fluorescent estradiol conjugate, we substituted polyethyleneglycol (PEG) for bovine serum albumin (BSA) and synthsized 17 beta-estradiol-6-carboxymethyl-oxime-PEG-fluorescein isothiocyanate. The structure of the title compound was confirmed by IR and UV. In this paper, we also describe another procedure to convert the terminal hydroxyl groups of PEG to the more reactive primary amino PEG by tosylation, azide group substitution and catalytic hydrogenation. The ratio of conversion is about 87%.

Estradiol↗