Morphological and molecular evidence for interspecific hybridisation in the introduced African genus Crassocephalum (Asteraceae: Senecioneae) in Asia

Abstract

The genus Crassocephalum in Asia, introduced there from Africa, was examined by extensive field work, herbarium studies, analyses of pollen and seed fertility, chromosome counts and ITS and trnL‐F sequencing. We found that Crassocephalum in Asia comprises two species and their interspecific hybrid. The two species are C. crepidioides (Benth.) S. Moore and C. rubens (Juss. ex Jacq.) S. Moore, of which the latter is a new record for Asia (north Thailand). The hybrid between these two species in north Thailand originated from a cross between C. crepidioides (2n = 40) as female and C. rubens (2n = 40) as male parent.     

Assigning fossil specimens to a given recent classification when the distribution of character variation is not normal

To help assign fossil material to Recent taxa we present a methodology that offers systematic quantitative tools to explore several continuous characters. It also enables the quantitative determination of which characters amongst several alternatives give results more consistent with a given classification.

The Gini Mean Difference ('Gini') is the expected absolute difference between two randomly drawn observations. In a fossil assemblage comprising several taxa, the Gini of the overall assemblage may be decomposed into three components: the weighted sum of intra‐taxon Gini, the index of overlap, and the inter‐taxon Gini. The parameter that is additional to alternative methods is the overlap index, which serves as a quantitative measure for evaluating the quality of identification. The Gini is advantageous in that it does not require the assumption of a normal distribution in character variation.

The Gini methodology is described in both mathematical and non‐mathematical terms. We demonstrate it by application to a hypothetical gastropod genus consisting of five species, in which we show in orderly, quantitative terms that one character is better for identification of the various species than another character.     

Determination of carbamazepine in human urine and serum samples by high‐performance liquid chromatography with post‐column Ru(bipy)‐Ce(SO4)2 chemiluminescence detection

A novel, sensitive and rapid CL method coupled with high‐performance liquid chromatography separation for the determination of carbamazepine is described. The method was based on the fact that carbamazepine could significantly enhance the chemiluminescence of the reaction of cerium sulfate and tris(2,2‐bipyridyl) ruthenium(II) in the presence of acid. The chromatographic separation was performed on a Kromasil® (Sigma‐Aldrich) TM RP‐C18 column (id: 150 mm × 4.6 mm, particle size: 5 µm, pore size: 100 Å) with a mobile phase consisting of methanol–water‐glacial acetic acid (70:29:1, v/v/v) at a flowrate of 1.0 mL/min, the total analysis time was within 650 s. Under optimal conditions, CL intensity was linear for carbamazepine in the range 2.0 × 10^?8 ~ 4.0 × 10^?5 g/mL, with a detection limit of 6.0 × 10^?9 g/mL (S/N = 3) and the relative standard detection was 2.5% for 2.0 × 10^?6 g/mL (n = 11). This method was successfully applied to the analysis of carbamazepine in human urine and serum samples. The possible mechanism of the CL reaction is also discussed briefly. Copyright © 2012 John Wiley & Sons, Ltd.     

Flow‐injection chemiluminescence determination of haemoglobin in the blood

In this study, a sensitive and simple flow‐injection chemiluminescence (CL) method was developed for the quantitative analysis of haemoglobin. The method is based on the ability of haemoglobin to enhance the CL signal generated by a H₂O₂–K₄Fe(CN)₆–fluorescein alkaline system enhanced by CdTe quantum dots. Under the optimized conditions, haemoglobin can be detected in concentration range 7.35 × 10^–9–2.5 × 10^–6 mol/L, with a detection limit (3σ) of 1.8 × 10^–9 mol/L and a relative standard deviation (RSD; for 5 × 10^–7 mol/L haemoglobin) of 2.06% (n = 11). The present CL method was successfully applied for the determination of haemoglobin in three kinds of blood samples taken from an infant, an adult man, an adult woman and two reference samples. Compared with previous reports, the CL method described in this work is simple and rapid, with high sensitivity. Copyright © 2012 John Wiley & Sons, Ltd.     

Highly sensitive chemiluminescence immunoassay on chitosan membrane modified paper platform using TiO2 nanoparticles/multiwalled carbon nanotubes as label

A highly sensitive chemiluminescence (CL) immunoassay was incorporated into a low‐cost microfluidic paper‐based analytical device (μ‐PAD) to fabricate a facile paper‐based CL immunodevice (denoted as μ‐PCLI). This μ‐PCLI was constructed by covalently immobilizing capture antibody on a chitosan membrane modified μ‐PADs, which was developed by simple wax printing methodology. TiO₂ nanoparticles coated multiwalled carbon nanotubes (TiO₂/MWCNTs) were synthesized as an amplification catalyst tag to label signal antibody (Ab₂). After sandwich‐type immunoreactions, the TiO₂/MWCNTs were captured on the surface of μ‐PADs to catalyze the luminol‐p‐iodophenol‐H₂O₂ CL system, which produced an enhanced CL emission. Using prostate‐specific antigen as a model analyte, the approach provided a good linear response range from 0.001 to 20 ng/mL with a low detection limit of 0.8 pg/mL under optimal conditions. This μ‐PCLI showed good reproducibility, selectivity and stability. The assay results of prostate‐specific antigen in clinical serum samples were in good agreement with that obtained by commercially used electrochemiluminescence methods at the Cancer Research Center of Shandong Tumor Hospital (Jinan, Shandong Province, China). This μ‐PCLI could be very useful to realize highly sensitive, qualitative point‐of‐care testing in developing or developed countries. Copyright © 2013 John Wiley & Sons, Ltd.     

Steady‐state and time‐resolved fluorescence of tetramethylrhodamine attached to DNA: correlation with DNA sequences

Time‐resolved fluorescence as well as steady‐state absorption and fluorescence were detected in order to study the interactions between tetramethylrhodamine (TAMRA) and DNA when TAMRA was covalently labeled on single‐ and double‐stranded oligonucleotides. Fluorescence intensity quenching and lifetime changes were characterized and correlated with different DNA sequences. The results demonstrated that the photoinduced electron transfer interaction between guanosine residues and TAMRA introduced a short lifetime fluorescence component when guanosine residues were at the TAMRA‐attached terminal of the DNA sequences. The discrepancy of two‐state and three‐state models in previous studies was due to the DNA sequence selection and sensitivity of techniques used to detect the short lifetime component. The results will help the design of fluorescence‐based experiments related to a dye labeled probe. Copyright © 2012 John Wiley & Sons, Ltd.     

Flow‐injection chemiluminescence determination of diazepam by oxidation with N‐bromosuccinimide

A rapid and sensitive flow‐injection chemiluminescence (FI–CL) method is described for the determination of diazepam based on its reaction with N‐bromosuccinimide (NBS) in alkaline medium in the presence of dichlorofluorescein (DCF) as an effective energy‐transfer agent. Under optimum conditions, the proposed method allowed the measurement of diazepam over the range of 2.0 × 10^?6 to 2.0 × 10^?4 mol/L with a detection limit of 5.0 × 10^?7 mol/L. The relative standard deviation for 11 parallel measurements of 2.0 × 10^?5 mol/L diazepam was 2.1%. The method was applied satisfactorily for the determination of diazepam in pharmaceutical preparations, and the results agree well with those obtained by spectrophotometry. The use of the proposed system for the determination of diazepam in urine and plasma samples was also tested. The possible mechanism of the chemiluminescence reaction is discussed briefly. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis and interaction of bovine serum albumin with p‐hydroxybenzoic acid derivatives

Three novel p‐hydroxybenzoic acid derivatives (HSOP, HSOX, HSCP) were synthesized from p‐hydroxybenzoic acid and sulfonamides (sulfamonomethoxine sodium, sulfamethoxazole and sulfachloropyridazine sodium) and characterized by elemental analysis, HNMR and MS. Interactions between derivatives and bovine serum albumin (BSA) were studied by fluorescence quenching spectra, UV–vis absorption spectra and time‐resolved fluorescence spectra. Based on fluorescence quenching calculation and Förster's non‐radioactive energy transfer theory, the values of the binding constants, basic thermodynamic parameters and binding distances were obtained. Experimental results indicated that the three derivatives had a strong ability to quench fluorescence from BSA and that the binding reactions of the derivatives with BSA were a static quenching process. Thermodynamic parameters showed that binding reactions were spontaneous and exothermic and hydrogen bond and van der Waals force were predominant intermolecular forces between the derivatives and BSA. Synchronous fluorescence spectra suggested that HSOX and HSCP had little effect on the microenvironment and conformation of BSA in the binding reactions but the microenvironments around tyrosine residues were disturbed and polarity around tyrosine residues increased in the presence of HSOP. Copyright © 2012 John Wiley & Sons, Ltd.     

A simple and sensitive spectrofluorimetric method for the determination of furosemide using zinc(II)–1,4‐bis(imidazol‐1‐ylmethyl)benzene complexes

A novel spectrofluorometric method for the determination of furosemide (FUR) is described. The method is based on enhancement of fluorescence emission of FUR in the presence of zinc (II) complexes of 1,4‐bis(imidazol‐1‐ylmethyl)benzene. Under optimum conditions, the enhanced fluorescence intensity is linearly related to the concentration of FUR. The proposed method has been successfully applied to the determination of FUR in pharmaceutical preparations. The possible mechanism of this reaction is discussed briefly based on data from fluorescence spectroscopy, UV–vis absorption and infrared spectroscopy. Copyright © 2012 John Wiley & Sons, Ltd.     

Rapid methods of detecting the target molecule in immunohistology using a bioluminescence probe

We demonstrate a novel rapid direct detection method for immunohistochemistry, using a bioluminescent probe. An anti‐CEA antibody‐fused far‐red bioluminescent protein can monitor the accumulation of this type of probe in tumour tissues. The bimodal spectrum (λ_max = 460 and 675 nm) of this bioluminescent probe is extremely stable under different conditions of pH and ion concentration. The sensitivity of our bioluminescent labelling was at the same level of enzymatic labelling, e.g. peroxidase, as an indirect system. Our novel technique is simple and can shorten the pretreatment time of paraffin sections to around 30 min. The utility of our bioluminescent labelling covers all imaging in vitro, in vivo and ex vivo, suggesting that our antibody‐fused bioluminescent probe has the potential to detect tumour antigens with a high sensitivity in routine immune histological examinations. Copyright © 2012 John Wiley & Sons, Ltd.