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Biomedical subjects

Hui Wang

Publications and source records attributed to Hui Wang.

At least 55 records · Page 3Linked to original sources
PubMed2006

The introgression of chromosome 6P specifying for increased numbers of florets and kernels from Agropyron cristatum into wheat.

A wheat (Triticum aestivum L.) line 4844 with superior numbers of florets and grains per spike was derived from the cross between Fukohokomugi wheat and Agropyron cristatum (L.) Gaertn. In order to determine the genetic control of floret and kernel number per spike in this line, chromosome addition and substitution lines that were derived from line 4844 were characterized by means of in situ hybridization, microsatellite (SSR), and gliadin analyses. Genomic in situ hybridization analysis with biotinylated P genomic DNA of A. cristatum as a probe demonstrated that the increased number of florets and grains in a spike was associated with the introgression of an A. cristatum chromosome. Fluorescence in situ hybridization, using a repetitive sequence, pAs1, derived from Aegilops squarrosa L., indicated the replacement of chromosome 6D of wheat in the wheat-A. cristatum chromosome substitution lines. This was confirmed by microsatellite analyses with wheat SSR markers specific for chromosome 6D, suggesting that the A. cristatum chromosome was homoeologous to group 6 and was therefore designated as 6P. This conclvsion was further confirmed by amplification using EST-SSR markers and gliadin analysis. The increased number of florets and kernels within a spike of the wheat-A. cristatum hybrids thus was controlled by gene(s) located on A. cristatum chromosome 6P.

Agropyron↗
PubMed2006

Determination of copper binding in Pseudomonas putida CZ1 by chemical modifications and X-ray absorption spectroscopy.

Previously performed studies have shown that Pseudomonas putida CZ1 biomass can bind an appreciable amount of Cu(II) and Zn(II) ions from aqueous solutions. The mechanisms of Cu- and Zn-binding by P. putida CZ1 were ascertained by chemical modifications of the biomass followed by Fourier transform infrared and X-ray absorption spectroscopic analyses of the living or nonliving cells. A dramatic decrease in Cu(II)- and Zn(II)-binding resulted after acidic methanol esterification of the nonliving cells, indicating that carboxyl functional groups play an important role in the binding of metal to the biomaterial. X-ray absorption spectroscopy was used to determine the speciation of Cu ions bound by living and nonliving cells, as well as to elucidate which functional groups were involved in binding of the Cu ions. The X-ray absorption near-edge structure spectra analysis showed that the majority of the Cu was bound in both samples as Cu(II). The fitting results of Cu K-edge extended X-ray absorption fine structure spectra showed that N/O ligands dominated in living and nonliving cells. Therefore, by combining different techniques, our results indicate that carboxyl functional groups are the major ligands responsible for the metal binding in P. putida CZ1.

Absorptiometry, Photon↗
PubMed2006

Attenuation of phagocytosis of xenogeneic cells by manipulating CD47.

Signal regulatory protein alpha (SIRPalpha) is a critical immune inhibitory receptor on macrophages, and its interaction with CD47, a ligand for SIRPalpha, prevents autologous phagocytosis. We hypothesized that interspecies incompatibility of CD47 may contribute to the rejection of xenogeneic cells by macrophages. Here, we show that pig CD47 does not interact with mouse SIPRalpha. Similar to CD47-/- mouse cells, porcine red blood cells (RBCs) failed to induce SIRPalpha tyrosine phosphorylation in mouse macrophages. Blocking SIRPalpha with antimouse SIRPalpha mAb (P84) significantly enhanced the phagocytosis of CD47+/+ mouse cells, but did not affect the engulfment of porcine or CD47-/- mouse cells by mouse macrophages. CD47-deficient mice, whose macrophages do not phagocytose CD47-/- mouse cells, showed markedly delayed clearance of porcine RBCs compared with wild-type mouse recipients. Furthermore, mouse CD47 expression on porcine cells markedly reduced their phagocytosis by mouse macrophages both in vitro and in vivo. These results indicate that interspecies incompatibility of CD47 contributes significantly to phagocytosis of xenogeneic cells by macrophages and suggest that genetic manipulation of donor CD47 to improve its interaction with the recipient SIRPalpha may provide a novel approach to prevent phagocyte-mediated xenograft rejection.

Animals↗
PubMed2006

Implications for viral capsid assembly from crystal structures of HIV-1 Gag(1-278) and CA(N)(133-278).

Gag, the major structural protein of retroviruses such as HIV-1, comprises a series of domains connected by flexible linkers. These domains drive viral assembly by mediating multiple interactions between adjacent Gag molecules and by binding to viral genomic RNA and host cell membranes. Upon viral budding, Gag is processed by the viral protease to liberate distinct domains as separate proteins. The first two regions of Gag are MA, a membrane-binding module, and CA, which is a two-domain protein that makes important Gag-Gag interactions, forms the cone-shaped outer shell of the core (the capsid) in the mature HIV-1 particle, and makes an important interaction with the cellular protein cyclophilin A (CypA). Here, we report crystal structures of the mature CA N-terminal domain (CA(N)(133-278)) and a MA-CA(N) fusion (Gag(1-278)) at resolutions/R(free) values of 1.9 A/25.7% and 2.2 A/25.8%, respectively. Consistent with earlier studies, a comparison of these structures indicates that processing at the MA-CA junction causes CA to adopt an N-terminal beta-hairpin conformation that seems to be required for capsid morphology and viral infectivity. In contrast with an NMR study (Tang, C., et al. (2002) Nat. Struct. Biol. 9, 537-543), structural overlap reveals only small relative displacements for helix 6, which is located between the beta-hairpin and the CypA-binding loop. These observations argue against the proposal that CypA binding is coupled with beta-hairpin formation and support an earlier surface plasmon resonance study (Yoo, S., et al. (1997) J. Mol. Biol. 269, 780-795), which concluded that beta-hairpin formation and CypA-binding are energetically independent events.

Amino Acid Sequence↗
PubMed2006

Pyrolysis mechanism of carbon matrix precursor cyclohexane--the formation of condensed-ring aromatics and the growing process of molecules.

Based on the experiments, the UAM1 method was adopted to investigate benzene condensation of an important intermediate and the molecule growing mechanism during the cyclohexane pyrolysis process. The conclusions were drawn as follows: (1) from the viewpoint of thermodynamics, the condensation of benzene and C4H5* is a spontaneous reaction and the rising temperature will increase the spontaneous tendency of the reaction. (2) From the viewpoint of kinetic, the condensation of benzene and C4H5* is a two-step reaction. The rate-determining step is step 2 of hydrogen removal from intermediate C10H10 (I1) with the activation energy of 350.61 kJ/mol below 1473 K while the rate-determining step is step 1 that free radical C4H5* attacks benzene to form intermediate C10H10 (I1) with the activation energy DeltaE(0)(not equal to theta)=31.74 kJ/mol above 1473 K. (3) The space structure, electronic structure and thermodynamics parameters of molecular reaction of dense-ring aromatizing compounds can be used to replace the resonance energy and free valence to judge the activation of thermodynamic reaction of compounds. And (4) the analysis of the space structure, electronic structure and thermodynamic parameters show that the growing process of molecules with benzene used as initial reactants becomes more easier as the multi-ring aromatizing molecular system increases.

Benzene↗
PubMed2006

Binuclear half-sandwich cobalt(III) and rhodium(III) ortho-carboranedichalocogenolato complexes with ether chain-bridged bis(cyclopentadienyl) ligand.

1, 1'-(3-Oxapentamethylene)dicyclopentadiene [O(CH(2)CH(2)C(5)H(5))(2)], containing a flexible chain-bridged group, was synthesized by the reaction of sodium cyclopentadienide with bis(2-chloroethyl) ether through a slightly modified literature procedure. Furthermore, the binuclear cobalt(III) complex O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(CO)I(2)](2) and insoluble polynuclear rhodium(III) complex {O[CH(2)CH(2)(eta(5)-C(5)H(4))RhI(2)](2)}(n) were obtained from reactions of with the corresponding metal fragments and they react easily with PPh(3) to give binuclear metal complexes, O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(PPh(3))I(2)](2) and O[CH(2)CH(2)(eta(5)-C(5)H(4))Rh(PPh(3))I(2)](2), respectively. Complexes react with bidentate dilithium dichalcogenolato ortho-carborane to give eight binuclear half-sandwich ortho-carboranedichalcogenolato cobalt(III) and rhodium(III) complexes O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(PPh(3))(E(2)C(2)B(10)H(10))](2) (E = S and Se), O[CH(2)CH(2)(eta(5)-C(5)H(4))](2)Co(2)(E(2)C(2)B(10)H(10)) (E = S and Se), O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(E(2)C(2)B(10)H(10))](2) (E = S and Se and O[CH(2)CH(2)(eta(5)-C(5)H(4))Rh(PPh(3))(E(2)C(2)B(10)H(10))](2) (E = S and Se). All complexes have been characterized by elemental analyses, NMR spectra ((1)H, (13)C, (31)P and (11)B NMR) and IR spectroscopy. The molecular structures were determined by X-ray diffractometry.

Journal Article↗
PubMed2006

[Bile salts induce differentiation in cultured human normal esophageal mucosal epithelial cells].

OBJECTIVE: To investigate the effects of bile salts on the proliferation and differentiation of human normal esophageal mucosal epithelial cells on cultured. METHODS: Normal human esophageal mucosa was obtained during operation. The esophageal epithelial cells were isolated, cultured, and treated with 6 different conjugated bile salts [glycocholate (GC), glycochenodeoxycholate (GCDC), glycodeoxycholate (GDC), taurochenodeoxycholate (TCDC), and taurodeoxycholate (TDC), all of the concentration of 50 micromol/L, and taurocholate (TC) of the concentration of 20 micromol/L], and their mixtures the concentration of 50 micromol/L respectively. One, three, and five days later MTT assay was applied to detect the cell proliferation. The cell cycle was assayed by flow cytometry with propidium iodide staining 1 and 3 d after treating with the bile salts. The cytokeratin 13 (CK13) in the differentiated cells and cytokeratin 14 (CK14) in the proliferating cells were detected by immunocytochemical assay. The concentration of intercellular calcium ([Ca(2+)]i) was analyzed by Laser Scanning Confocal Microscope (LSCM) in cells with TC, mixed bile salts and GC. RESULTS: The cultured esophageal epithelial cells treated by the bile salts, except those treated by GC for 1 - 3 days, became larger and shuttle-like, with the cell proliferation inhibited, the percentages of cells in G(0)-G(1) phase increased and percentages of cells in S phase decreased. The percentages of CK14 positive cells were increased, but the percentages of CK13 positive cells were decreased time-dependently in cells treated for 1 - 5 days. The most obvious effects were seen in those cells treated with TC. The percentage of CK13 positive cells reached 74% +/- 8% in those cells treated with TC for 5 days, higher significantly than the percentage in the control cell (22% +/- 7%), (P < 0.01). The [Ca(2+)]i increased significantly only several minutes after treatment of TC and mixed bile salts, however, GC failed to cause the increase of [Ca(2+)]i. CONCLUSION: GCDC, GDC, TC, TCDC, TDC and their mixture all induce differentiation of cultured human normal esophageal mucosal epithelial cells, but nor does GC. Increased [Ca(2+)]i is related to the TC-induced differentiation in those esophageal mucosal epithelial cells.

Bile Acids and Salts↗
PubMed2006

NYD-SP15: a novel gene potentially involved in regulating testicular development and spermatogenesis.

By hybridizing human adult testis cDNA microarrays with human adult and embryo testis cDNA probes, we identified a novel human testis gene, NYD-SP15. NYD-SP15 expression was 3.26-fold higher in adult than in fetal testis; however, there was almost no NYD-SP15 expression in the sperm. NYD-SP15 comprises 3364 base pairs, including a 1545 bp open reading frame encoding a 514 amino acid protein possessing 89% sequence identity with the mouse testis homologous protein. NYD-SP15 is located on human chromosome 13q14.2. The deduced structure of the protein contains two dCMP_cyt_deam domains, indicating a potential functional role for zinc ion binding. The gene is expressed variably in a wide range of tissues, with high expression levels in the testis. Sequence analysis revealed that NYD-SP15 is not a highly conserved protein, with its distribution in high-level species such as vertebrates including Homo, Mus, Rattus, and Canis. The results of semiquantitative polymerase chain reaction in mouse testis representing different developmental stages indicate that NYD-SP15 expression was developmentally regulated. These results suggest the putative NYD-SP15 protein may play an important role in testicular development and spermatogenesis and may be an important factor governing male infertility.

Amino Acid Sequence↗
PubMed2006

Hydrolytic kinetics of lithospermic acid B extracted from roots of Salvia miltiorrhiza.

The hydrolytic kinetics of lithospermic acid B (LAB) extracted from the roots of Salvia miltiorrhiza (Chinese herb: danshen) was investigated by using reversed-phase high-performance liquid chromatography (HPLC) with UV-vis detection. The influences of initial drug concentration, pH and temperature on hydrolysis of LAB were studied in aqueous solutions. The results showed that initial concentration of LAB has no effect on the degradation rate at pH 2.0. The hydrolysis followed pseudo-first-order kinetics at 90 degrees C. The log k(obs)-pH profile indicated that the optimal stability range was at pH 2.0-5.0. The rate constant of overall hydrolysis as a function of temperature under the given conditions obeyed the Arrhenius equation. Analysis of the acid-induced degraded solution of LAB by liquid chromatography-mass spectrometry (LC-MS) revealed at least four degradation products [M-H](-) ion at m/z 197, 137, 537 and 537, respectively. Three of these degradation products, i.e. danshensu (DSU), protocatechuic aldehyde (PRO), and lithospermic acid, were further identified by comparing the retention times with standard samples. According to the structure of LAB and its hydrolysis behavior in solution, the other product was proposed to be the isomer of lithospermic acid.

Benzaldehydes↗
PubMed2006

Preclinical characterization of AEG35156/GEM 640, a second-generation antisense oligonucleotide targeting X-linked inhibitor of apoptosis.

PURPOSE: Cancer cells can use X-linked inhibitor of apoptosis (XIAP) to evade apoptotic cues, including chemotherapy. The antitumor potential of AEG35156, a novel second-generation antisense oligonucleotide directed toward XIAP, was assessed in human cancer models when given as a single agent and in combination with clinically relevant chemotherapeutics. EXPERIMENTAL DESIGN: AEG35156 was characterized for its ability to cause dose-dependent reductions of XIAP mRNA and protein in vitro and in vivo, to sensitize cancer cell lines to death stimuli, and to exhibit antitumor activity in multiple human cancer xenograft models as a single agent or in combination with chemotherapy. RESULTS: AEG35156 reduced XIAP mRNA levels with an EC50 of 8 to 32 nmol/L and decreased XIAP protein levels by >80%. Loss of XIAP protein correlated with increased sensitization to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in Panc-1 pancreatic carcinoma cells. AEG35156 exhibited potent antitumor activity relative to control oligonucleotides in three human cancer xenograft models (prostate, colon, and lung) and was capable of inducing complete tumor regression when combined with taxanes. Antitumor effects of AEG35156 correlated with suppression of tumor XIAP levels. CONCLUSIONS: AEG35156 reduces XIAP levels and sensitizes tumors to chemotherapy. AEG35156 is presently under clinical assessment in multiple phase I trials in cancer patients as a single agent and in combination with docetaxel in solid tumors or cytarabine/idarubicin in leukemia.

Animals↗
PubMed2006

Mutation at Glu23 eliminates the neuron growth inhibitory activity of human metallothionein-3.

Human metallothionein-3 (hMT3), first isolated and identified as a neuronal growth inhibitory factor (GIF), is a metalloprotein expressed predominantly in brain. However, until now, the exact mechanism of the bioactivity of hMT3 is still unknown. In order to study the influence of acid-base catalysis on S-nitrosylation of hMT3, we constructed the E23K mutant of hMT3. During the course of bioassay, we found out unexpectedly that mutation at E23 of hMT3 eliminates the neuronal growth inhibitory activity completely. To the best of our knowledge, it is the first report that other residues, besides the TCPCP motif, in the beta-domain can alter the bioactivity of hMT3. In order to figure out the causes for the loss of bioactivity of the E23K mutant, the biochemical properties were characterized by UV-vis spectroscopy, CD spectroscopy, pH titration, DTNB reaction, EDTA reaction, and SNOC reaction. All data demonstrated that stability of the metal-thiolate cluster and overall structure of the E23K mutant were not altered too much. However, the reaction of the E23K mutant with SNOC exhibited biphasic kinetics and the mutant protein released zinc ions much faster than hMT3 in the initial step, while hMT3 exhibited single kinetic process. The 2D [1H-15N] HSQC was also employed to characterize structural changes during the reaction of hMT3 with varying mounts of nitric oxide. It was shown that the resonance of Glu23 disappeared at a molar ratio of NO to protein of 4. Based on these results, we suggest that mutation at Glu23 may alter the NO metabolism and/or affect zinc homeostasis in brain, thus altering the neuronal growth inhibitory activity.

Animals↗
PubMed2006

In vitro anti-cancer activity and structure-activity relationships of natural products isolated from fruits of Panax ginseng.

PURPOSE: Panax ginseng and its extracts have long been used for medical purposes; there is increasing interest in developing ginseng products as cancer preventive or therapeutic agents. The present study was designed to determine biological structure-activity relationships (SAR) for saponins present in Panax ginseng fruits. METHODS: Eleven saponins were extracted from P. ginseng fruits and purified by use of D(101) resin and ordinary and reverse-phase silica gel column chromatography. Their chemical structures were elucidated on the basis of physicochemical constants and NMR spectra. Compounds were then evaluated for SAR with their in vitro cytotoxicity against several human cancer cell lines. RESULTS: The 11 compounds were identified as 20(R)-dammarane-3beta,12beta,20,25-tetrol (25-OH-PPD, 1); 20(R)-dammarane-3beta,6alpha,12beta,20,25-pentol (25-OH-PPT, 2); 20(S)-protopanaxadiol (PPD, 3); daucosterine 4, 20(S)-ginsenoside-Rh(2) (Rh(2), 5); 20(S)-ginsenoside-Rg(3) (Rg(3,) 6); 20(S)-ginsenoside-Rg(2) (Rg(2), 7); 20(S)-ginsenoside-Rg(1) (Rg(1), 8); 20(S)-ginsenoside-Rd (Rd, 9); 20(S)-ginsenoside-Re (Re, 10); and 20(S)-ginsenoside-Rb(1) (Rb(1), 11). Among the eleven compounds, 1, 3 and 5 were the most effective inhibitors of cell growth and proliferation and inducers of apoptosis and cell cycle arrest. For 1, the IC(50) values for most cell lines were in the range of 10-60 microM, at least twofold lower than for any of the other compounds. Compounds 1 and 3 had significant, dose-dependent effects on apoptosis, proliferation, and cell cycle progression. CONCLUSIONS: The results suggest that the type of dammarane, the number of sugar moieties, and differences in the substituent groups affect their anti-cancer activity. This information may be useful for evaluating the structure/function relationship of other ginsenosides and their aglycones and for development of novel anticancer agents.

Antineoplastic Agents, Phytogenic↗
PubMed2006

Design, synthesis, and biological evaluation of a new class of small molecule peptide mimetics targeting the melanocortin receptors.

A new bicyclic template has been developed for the synthesis of peptide mimetics. Straightforward synthetic steps, starting from amino acids, allow the facile construction of a wide range of analogs. This system was designed to target the melanocortin receptors (MCRs), with functional group selection based on a known pharmacophore and guidance from molecular modeling to rationally identify positional and stereochemical isomers likely to be active. The functions of hMCRs are critical to myriad biological activities, including pigmentation, steroidogenesis, energy homeostasis, erectile activity, and inflammation. These G-protein-coupled receptors (GPCRs) are targets for drug discovery in a number of areas, including cancer, pain, and obesity therapeutics. All compounds from this series tested to date are antagonists which bind with high affinity. Importantly, many are highly selective for a particular MCR subtype, including some of the first completely hMC5R-selective antagonists reported.

Binding Sites↗
PubMed2006

Fructose-induced peroxynitrite production is mediated by methylglyoxal in vascular smooth muscle cells.

Methylglyoxal (MG), a highly reactive molecule, has been implicated in the development of insulin resistance. We investigated whether fructose, a precursor of MG, induced ONOO(-) generation and whether this process was mediated via endogenously increased MG formation. Fructose significantly increased MG generation in vascular smooth muscle cells (VSMCs) in a concentration and time dependent manner. The intracellular production of MG was increased by 153+/-23% or 259+/-28% after cells were treated 6 h with fructose (15 mM or 30 mM), compared with production from untreated cells (p<0.01, n=4 for each group). A significant increase in the production of ONOO(-), NO, and O(2)(*-), was found in the cells treated with fructose (15 mM) or MG (10 microM). Fructose- or MG-induced ONOO(-) generation was significantly inhibited by MG scavengers, including reduced glutathione or N-acetyl-l-cysteine, and by O(2)(*-) or NO inhibitors, such as diphenylene iodonium, superoxide dismutase or N-nitro-l-arginine methyl ester. Moreover, an enhanced iNOS expression was also observed in the cells treated directly with MG which was significantly inhibited when co-application with N-acetyl-l-cysteine. Our results demonstrated that fructose is capable of inducing a significant increase in ONOO(-) production, which is mediated by an enhanced formation of endogenous MG in VSMCs.

Acetylcysteine↗
PubMed2006

Adsorption of copper and zinc on Pseudomonas putida CZ1: particle concentration effect and adsorption reversibility.

The adsorption and desorption processes of Cu(II) and Zn(II) on the biomass of Pseudomonas putida CZ1 as a function of particle concentrations (C(p)) were studied. In a 0.01 M KNO3 solution, the Cu-biomass and Zn-biomass adsorption systems displayed a clear C(p) effect. The overall adsorption isotherms under three C(p) conditions could be described as a Freundlich-type C(p) effect isotherm equation: gamma = 2.553C(p)(-0.7106) C(eq)(0.8971) for Cu-biomass system, gamma = 2.412C(p)(-0.8305) C(eq)(0.6504) for Zn-biomass system. The results of experiments, designed to eliminate several typical sources of experimental artifact, agree with the prediction of the metastable-equilibrium adsorption theory. Results from laboratory equilibration studies also indicate that biomass-adsorbed Cu(II) or Zn(II) fractions may be comprised of both reversibly and strongly bound or resistant components. A computational method has been derived to allow prediction of the magnitude of the reversible and more strongly adsorbed Cu(II) or Zn(II) fractions from conventional isotherm data. This methodology provides an initial quantitative approximation of the strongly bound, resistant, biomass fractions while utilizing relatively simple experimental adsorption-desorption data.

Adsorption↗
PubMed2006

The influence of soil heavy metals pollution on soil microbial biomass, enzyme activity, and community composition near a copper smelter.

The environmental risk of heavy metal pollution is pronounced in soils adjacent to large industrial complexes. It is important to investigate the functioning of soil microorganisms in ecosystems exposed to long-term contamination by heavy metals. We studied the potential effects of heavy metals on microbial biomass, activity, and community composition in soil near a copper smelter in China. The results showed that microbial biomass C was negatively affected by the elevated metal levels and was closely correlated with heavy metal stress. Enzyme activity was greatly depressed by conditions in the heavy metal-contaminated sites. Good correlation was observed between enzyme activity and the distance from the smelter. Elevated metal loadings resulted in changes in the activity of the soil microbe, as indicated by changes in their metabolic profiles from correlation analysis. Significant decrease of soil phosphatase activities was found in the soils 200 m away from the smelter. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis demonstrated that heavy metals pollution had a significant impact on bacterial and actinomycetic community structure. There were negative correlations between soil microbial biomass, phosphatase activity, and NH(4)NO(3) extractable heavy metals. The soil microorganism activity and community composition could be predicted significantly using the availability of Cu and Zn. By combining different monitoring approaches from different viewpoints, the set of methods applied in this study were sensitive to site differences and contributed to a better understanding of heavy metals effects on the structure, size and activity of microbial communities in soils. The data presented demonstrate the role of heavy metals pollution in understanding the heavy metal toxicity to soil microorganism near a copper smelter in China.

Actinobacteria↗
PubMed2006

Selective thiourea optical probe based on thiourea-induced removal of chloroacetyl group from chloroacetylamine.

A novel chromogenic probe for thiourea, N-chloroacetyl parafuchsin (CAP), was designed and synthesized. The method was based on the reaction of CAP with thiourea, resulting in the initial formation of the S-substituted thioformamidine hydrochloride, which would then undergo the intramolecular amidinolysis to liberate the corresponding amine, and thus leading to an absorbance increase at visible spectral range. Based on this mechanism, a highly selective optical probe for thiourea was developed. Under optimal conditions, absorbance increase (DeltaA) at 562 nm is proportional to thiourea concentration up to 0.2 mmolL(-1) with a detection limit of 2.1 micromolL(-1) (3sigma). Because of the selective removal of chloroacetyl group from CAP by thiourea, there is little interference by other molecules.

Acetamides↗