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1.
Inorg Chem ; 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32323981

RESUMO

Transition metal phosphides (TMPs) have gained increased attention in energy storage due to their potential applications for optimizing electrochemical performances. However, their preparation routes usually require highly toxic and flammable phosphorus sources with strict reaction conditions. The existence of multiple energetically favorable stoichiometries also makes it a challenge to achieve phase control of metal phosphides. In this work, we have successfully realized the phase-controllable framework of cobalt phosphide from Co2P to CoP by employing a semi-interpenetrating network (semi-IPN) hydrogel as a precursor. Interestingly, the semi-IPN hydrogel could serve as a self-assembly/sacrificing template to accomplish 3D space confinement, where poly(vinylphosphonic acid) (PVPA) was identified as a prominent phosphorus source due to its strong metal complexation ability and high thermal stability. Furthermore, this route is successfully extended to the synthesis of other TMPs, including Fe2P, Ni2P, and Cu3P. The specific structure of cobalt phosphides gives rise to superior lithium storage performance, showing superior cycling stability (495.2 mAh g-1 after 1000 cycles at 2.0 A g-1). This approach envisions a new outlook on exploitation of essential functional hydrogels for the creation of inorganic materials toward sustainable energy development.

2.
Small ; 16(5): e1905842, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31916666

RESUMO

Rechargeable Zn/MnO2 batteries using mild aqueous electrolytes are attracting extensive attention due to their low cost, high safety, and environmental friendliness. However, the charge-storage mechanism involved remains a topic of controversy so far. Also, the practical energy density and cycling stability are still major issues for their applications. Herein, a free-standing α-MnO2 cathode for aqueous zinc-ion batteries (ZIBs) is directly constructed with ultralong nanowires, leading to a rather high energy density of 384 mWh g-1 for the entire electrode. Greatly, the H+ /Zn2+ coinsertion mechanism of α-MnO2 cathode for aqueous ZIBs is confirmed by a combined analysis of in situ X-ray diffractometry, ex situ transmission electron microscopy, and electrochemical methods. More interestingly, the Zn2+ -insertion is found to be less reversible than H+ -insertion in view of the dramatic capacity fading occurring in the Zn2+ -insertion step, which is further evidenced by the discovery of an irreversible ZnMn2 O4 layer at the surface of α-MnO2 . Hence, the H+ -insertion process actually plays a crucial role in maintaining the cycling performance of the aqueous Zn/α-MnO2 battery. This work is believed to provide an insight into the charge-storage mechanism of α-MnO2 in aqueous systems and paves the way for designing aqueous ZIBs with high energy density and long-term cycling ability.

3.
Pest Manag Sci ; 76(3): 917-927, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31444936

RESUMO

BACKGROUND: To enhance discovering efficiency of new herbicidal compounds, a strategy for rapidly screening out strongly herbicidal chemical components from natural resources is necessary. RESULTS: Seventeen essential oils selected from 14 Eucalyptus species and hybrids were evaluated for their herbicidal activities on annual ryegrass. A feasible strategy was established for rapidly pinpointing the chemicals contributing to strong herbicidal activities without the process of isolation and purification of individual compounds. This strategy was based on gas chromatography-mass spectrometry (GC-MS) coupled with principal component analysis (PCA) and verified by the bioassay results using several individual compounds. Two strong herbicidal compounds trans-pinocarveol and α-terpineol were screened out using the strategy. The strong herbicidal activity of trans-pinocarveol was discovered for the first time. CONCLUSION: The established strategy of screening herbicidal compounds from natural resources is simple, feasible and reliable. © 2019 Society of Chemical Industry.


Assuntos
Eucalyptus , Óleo de Eucalipto , Cromatografia Gasosa-Espectrometria de Massas , Folhas de Planta
4.
Mikrochim Acta ; 186(9): 663, 2019 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-31473835

RESUMO

The enzyme histone acetyltransferase (HAT) catalyzes the acetylation of a substrate peptide, and acetyl coenzyme A is converted to coenzyme A (CoA). A photoelectrochemical method is described for the determination of the HAT activity by using exfoliated MoS2 nanosheets, phos-tag-biotin, and ß-galactosidase (ß-Gal) based signal amplification. The MoS2 nanosheets are employed as the photoactive material, graphene nanosheets as electron transfer promoter, gold nanoparticles as recognition and capture reagent for CoA, and phos-tag-biotin as the reagent to link CoA and ß-Gal. The enzyme ß-Gal catalyzes the hydrolysis of substrate O-galactosyl-4-aminophenol to generate free 4-aminophenol which is a photoelectrochemical electron donor. The photocurrent increases with the activity of HAT. Under optimal conditions, the response is linear in the 0.3 to 100 nM activity range, and the detection limit is 0.14 nM (at S/N = 3). The assay was applied to HAT inhibitor screening, specifically for the inhibitors C646 and anacardic acid. The IC50 values are 0.28 and 39 µM, respectively. The method is deemed to be a promising tool for epigenetic research and HAT-targeted cancer drug discovery. Graphical abstract Histone acetyltransferase was detected using a sensitive photoelectrochemical method using MoS2 nanosheets as photoactive material.


Assuntos
Técnicas Biossensoriais , Dissulfetos/química , Técnicas Eletroquímicas , Inibidores Enzimáticos/análise , Histona Acetiltransferases/antagonistas & inibidores , Histona Acetiltransferases/análise , Molibdênio/química , Nanopartículas/química , Ácidos Anacárdicos/análise , Ácidos Anacárdicos/farmacologia , Benzoatos/análise , Benzoatos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacologia , Histona Acetiltransferases/metabolismo , Humanos , Tamanho da Partícula , Processos Fotoquímicos , Pirazóis/análise , Pirazóis/farmacologia , Propriedades de Superfície
5.
Mikrochim Acta ; 186(8): 488, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267252

RESUMO

A nanocomposite was prepared from ß-cyclodextrin (ß-CD) functionalized graphene oxide and magnetic nanoparticles (GO/Fe3O4/ß-CD). In parallel, a polyamidoamine dendrimer conjugated to avidinylated alkaline phosphatase (PAMAM-avidin-ALP) was prepared and exploited as a signal amplification unit in a voltammetric immunoassay for 5-methylcytosine (5mC) in genomic DNA. The GO/Fe3O4/ß-CD as a substrate material exhibited good solubility, electrical conductivity and large surface. This is beneficial for the further modification of antibodies (Ab) by host-guest interaction and amide bonds. By taking advantage of three-dimensional structure to capture avidin-ALP by amide linkages, PAMAM was used as a catalytic signal amplification element in this assay. Under the optimized condition and at a typical working potential of 0.94 V, the response to 5mC is linear in the 0.01-50 nM concentration range with a detection limit of 3.2 pM (at S/N = 3). The method is stable, selective and reproducible. It was applied to the determination of 5mC in genomic DNA of human tissue. Graphical abstract An electrochemical immunoassay was constructed for 5-methylcytosine detection based on nanocomposite of graphene oxide, magnetite nanoparticles and ß-cyclodextrin, and enzymatic signal amplification.


Assuntos
5-Metilcitosina/análise , Técnicas Biossensoriais , 5-Metilcitosina/química , Fosfatase Alcalina/química , Avidina/química , Mama , Neoplasias da Mama/genética , DNA/química , Dendrímeros/química , Técnicas Eletroquímicas , Feminino , Grafite/química , Humanos , Imunoensaio , Nanopartículas de Magnetita/química , Nanocompostos/química , Estômago , Neoplasias Gástricas/genética , beta-Ciclodextrinas/química
6.
Biosens Bioelectron ; 142: 111516, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31326863

RESUMO

A novel photoelectrochemical biosensor was fabricated for 5-hydroxymethylcytosine (5hmC) detection based on the photocurrent inhibition effect of ZnO on MoS2/C3N4 heterojunction. Firstly, the ITO electrode was modified successively with MoS2 and g-C3N4 as photoelectric materials to deliver a strong photocurrent response. Next, the 5-hydroxymethyl group (-CH2OH) of 5hmC was oxidized by KRuO4 to produce an aldehyde group (-CHO), where 5hmC was converted into 5-formylcytosine (5fC). Based on the covalent reaction with between -CHO of 5fC and -NH2 groups of g-C3N4, 5fC can be captured on electrode surface. Finally, the ZnO-PAMAM composite was covalently attached to the phosphate group of the immobilized 5fC, which could decrease the electron transfer amount of g-C3N4 to MoS2, absorption of light and consumption of electron donors thereby resulting the decrease of photocurrent. Under optimal conditions, the photocurrent shows a linear relationship with the logarithm value of 5hmC concentration from 0.01-200 nM with a low detection limit of 2.6 pM. Moreover, this method was selective and allowed to discriminate between 5hmC and 5-methylcytosine (5mC) in DNA. Finally, the photoelectrochemical biosensor was successfully applied to investigate the effect of heavy metal ion and phytohormones on 5hmC expression in rice seedlings leaves.


Assuntos
5-Metilcitosina/análogos & derivados , Técnicas Biossensoriais/instrumentação , Dissulfetos/química , Molibdênio/química , Nitrilos/química , Óxido de Zinco/química , 5-Metilcitosina/análise , Técnicas Biossensoriais/métodos , Condutividade Elétrica , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Desenho de Equipamento , Luz , Limite de Detecção , Oryza/química , Processos Fotoquímicos , Folhas de Planta/química
7.
Chem Commun (Camb) ; 55(18): 2712-2715, 2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30758023

RESUMO

A visible-light-induced difluoroalkylation of N,N'-cyclicazomethine imine was successfully realized through a novel photoredox radical-radical cross-coupling reaction. This developed protocol exhibits high functional group tolerance and affords a variety of difluorinated 3-pyrazolidinone scaffolds. Extensive mechanistic investigations have been undertaken, well revealing the involvement of a reductive radical-radical coupling pathway.

8.
Front Genet ; 9: 374, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30254661

RESUMO

Flaxleaf fleabane (Conyza bonariensis [L.] Cronquist) is one of the most difficult weeds to control worldwide. There are more than 150 Conyza species in the world and eight species in Australia. Correct identification of these species can be problematic due to their morphological similarities especially at seedling stage. Developing a robust genetics - based species identification method to distinguish C. bonariensis from other closely related species is important for early control of weeds. We thus examined the chloroplast (cp) genome of C. bonariensis, aiming to identify novel DNA barcodes from the genome sequences, and use the entire cp genome as a super-barcode for molecular identification. The C. bonariensis chloroplast genome is 152,076 bp in size, encodes 133 genes including 88 protein-coding genes, 37 tRNA genes and 8 ribosomal RNA genes. A total of 151 intergenic regions and 19 simple sequence repeats were identified in the cp genome of C. bonariensis, which provides a useful genetic resource to develop robust markers for the genetic diversity studies of Conyza species. The sequence information was used to design a robust DNA barcode rps16 and trnQ-UUG which successfully separated three predominant Conyza species (C. bonariensis, C. canadensis, and C. sumatrensis). Phylogenetic analyses based on the cp genomes of C. bonariensis, C. canadensis and 18 other Asteraceae species revealed the potential of using entire cp genome as a plant super-barcode to distinguish closely-related weed species.

9.
Genome Announc ; 5(47)2017 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-29167241

RESUMO

Nassella hyalina (cane needle grass) is on the Alert List for Environmental Weeds in Australia. We present here the first complete chloroplast sequence of N. hyalina reconstructed from Illumina whole-genome sequencing. The complete chloroplast sequence is 137,606 bp in size and has a gene content and structure similar to those of other published chloroplast genomes of Stipeae.

10.
PLoS One ; 12(4): e0175338, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28399170

RESUMO

Invasive grass weeds reduce farm productivity, threaten biodiversity, and increase weed control costs. Identification of invasive grasses from native grasses has generally relied on the morphological examination of grass floral material. DNA barcoding may provide an alternative means to identify co-occurring native and invasive grasses, particularly during early growth stages when floral characters are unavailable for analysis. However, there are no universal loci available for grass barcoding. We herein evaluated the utility of six candidate loci (atpF intron, matK, ndhK-ndhC, psbE-petL, ETS and ITS) for barcode identification of several economically important invasive grass species frequently found among native grasses in eastern Australia. We evaluated these loci in 66 specimens representing five invasive grass species (Chloris gayana, Eragrostis curvula, Hyparrhenia hirta, Nassella neesiana, Nassella trichotoma) and seven native grass species. Our results indicated that, while no single locus can be universally used as a DNA barcode for distinguishing the grass species examined in this study, two plastid loci (atpF and matK) showed good distinguishing power to separate most of the taxa examined, and could be used as a dual locus to distinguish several of the invasive from the native species. Low PCR success rates were evidenced among two nuclear loci (ETS and ITS), and few species were amplified at these loci, however ETS was able to genetically distinguish the two important invasive Nassella species. Multiple loci analyses also suggested that ETS played a crucial role in allowing identification of the two Nassella species in the multiple loci combinations.


Assuntos
Código de Barras de DNA Taxonômico , DNA de Plantas/genética , Espécies Introduzidas , Poaceae/genética , Austrália , Filogenia , Poaceae/classificação , Reação em Cadeia da Polimerase
11.
Environ Sci Pollut Res Int ; 23(22): 23175-23183, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27600727

RESUMO

Cover crop species are usually grown to control weeds. After cover crop harvest, crop residue is applied on the ground to improve soil fertility and crop productivity. Little information is available about quantifying the contributions of cover crop application to soil total carbon (C) and nitrogen (N) contents in temperate Australia. Here, we selected eight cover crop treatments, including two legume crops (vetch and field pea), four non-legume crops (rye, wheat, Saia oat, and Indian mustard), a mixture of rye and vetch, and a nil-crop control in temperate Australia to calculate the contributions of cover crops (crop growth + residue decomposition) to soil C and N contents. Cover crops were sown in May 2009 (autumn). After harvest, the crop residue was placed on the soil surface in October 2009. Soil and crop samples were collected in October 2009 after harvest and in May 2010 after 8 months of residue decomposition. We examined cover crop residue biomass, soil and crop total C and N contents, and soil microbial biomass C and N contents. The results showed that cover crop application increased the mean soil total C by 187-253 kg ha-1 and the mean soil total N by 16.3-19.1 kg ha-1 relative to the nil-crop treatment, except for the mixture treatment, which had similar total C and N contents to the nil-crop control. Cover crop application increased the mean soil microbial biomass C by 15.5-20.9 kg ha-1 and the mean soil microbial biomass N by 4.5-10.2 kg ha-1. We calculated the apparent percentage of soil total C derived from cover crop residue C losses and found that legume crops accounted for 10.6-13.9 %, whereas non-legume crops accounted for 16.4-18.4 % except for the mixture treatment (0.2 %). Overall, short-term cover crop application increased soil total C and N contents and microbial biomass C and N contents, which might help reduce N fertilizer use and improve sustainable agricultural development.


Assuntos
Carbono/análise , Fabaceae/química , Nitrogênio/análise , Solo/química , Agricultura/métodos , Austrália , Biomassa , Produtos Agrícolas/crescimento & desenvolvimento
12.
Tumour Biol ; 37(8): 11385-95, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26968553

RESUMO

Basal-like breast cancer (BLBC) and triple-negative breast cancer (TNBC) are two entities of breast cancer that share similar poor prognosis. Even though both cancers have overlaps, there are still some differences between those two types. It has been reported that the c-Met high expression was associated with poor prognosis not only in breast cancer but also in many other cancers. The role of ERß in pathogenesis and treatment of breast cancer has remained controversial. In this study, we firstly distinguished basal-like from nonbasal-like cancer patients in TNBC patients using CK5/6 and EGFR as markers and next determined the relationship of basal-like breast cancer with c-Met or ERß expression levels and prognosis in TNBC patients. One hundred twenty-seven patients who had been diagnosed with TNBC were enrolled. The clinical and pathological characteristics of the patients were recorded. The expression of EGFR, CK5/6, ERß, and c-Met were evaluated with immunohistochemical methods using paraffin blocks. The median age of patients was 50.7 years. CK5/6 immunopositivity was 31.5 % (40/127), and EGFR was 40.2 % (51/127). Of the TNBC cases, 55.1 % (71/127) were positive for either CK5/6 or EGFR and were thus classified as basal-like breast cancer. C-Met (P < 0.001) and ERß (P = 0.002) overexpression, small tumor sizes, a ductal subtype, and high-grade tumor were significantly correlated with BLBC. High c-Met expression was detected in 43.3 % patients. Metastatic lymph nodes and tumor size (>5 cm), which were both important prognostic predictors, were significantly associated with recurrence and mortality. BLBC typically demonstrates a unique profile. CK5/6 and EGFR expression combination indicates a higher basal-like phenotype possibility. The expression of c-Met and ERß were significantly related to the basal-like phenotype. The classical markers, lymph node metastasis, and tumor size were found to have important prognostic value. However, high c-Met expression and basal-like phenotypes did not show a direct correlation with poor prognosis.


Assuntos
Biomarcadores Tumorais/análise , Receptor beta de Estrogênio/biossíntese , Proteínas Proto-Oncogênicas c-met/biossíntese , Neoplasias de Mama Triplo Negativas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Receptor beta de Estrogênio/análise , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Fenótipo , Prognóstico , Modelos de Riscos Proporcionais , Proteínas Proto-Oncogênicas c-met/análise , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/mortalidade , Adulto Jovem
13.
PLoS One ; 10(6): e0130475, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26057386

RESUMO

Redroot pigweed is one of the injurious agricultural weeds on a worldwide basis. Understanding of its interference impact in crop field will provide useful information for weed control programs. The effects of redroot pigweed on cotton at densities of 0, 0.125, 0.25, 0.5, 1, 2, 4, and 8 plants m(-1) of row were evaluated in field experiments conducted in 2013 and 2014 at Institute of Cotton Research, CAAS in China. Redroot pigweed remained taller and thicker than cotton and heavily shaded cotton throughout the growing season. Both cotton height and stem diameter reduced with increasing redroot pigweed density. Moreover, the interference of redroot pigweed resulted in a delay in cotton maturity especially at the densities of 1 to 8 weed plants m(-1) of row, and cotton boll weight and seed numbers per boll were reduced. The relationship between redroot pigweed density and seed cotton yield was described by the hyperbolic decay regression model, which estimated that a density of 0.20-0.33 weed plant m(-1) of row would result in a 50% seed cotton yield loss from the maximum yield. Redroot pigweed seed production per plant or per square meter was indicated by logarithmic response. At a density of 1 plant m(-1) of cotton row, redroot pigweed produced about 626,000 seeds m(-2). Intraspecific competition resulted in density-dependent effects on weed biomass per plant, a range of 430-2,250 g dry weight by harvest. Redroot pigweed biomass ha(-1) tended to increase with increasing weed density as indicated by a logarithmic response. Fiber quality was not significantly influenced by weed density when analyzed over two years; however, the fiber length uniformity and micronaire were adversely affected at density of 1 weed plant m(-1) of row in 2014. The adverse impact of redroot pigweed on cotton growth and development identified in this study has indicated the need of effective redroot pigweed management.


Assuntos
Amaranthus/crescimento & desenvolvimento , Gossypium/crescimento & desenvolvimento , Plantas Daninhas/crescimento & desenvolvimento , Amaranthus/anatomia & histologia , Biomassa , Fibra de Algodão , Gossypium/anatomia & histologia , Caules de Planta/anatomia & histologia , Plantas Daninhas/anatomia & histologia , Chuva , Reprodução , Estações do Ano , Sementes/crescimento & desenvolvimento , Temperatura
14.
PLoS One ; 9(3): e93189, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24681490

RESUMO

The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii) have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.). The aqueous volatile fractions (AVFs) were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions) during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph-mass spectrometry (GC-MS). Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species.


Assuntos
Eucalyptus/química , Óleos Voláteis/química , Extratos Vegetais/química , Óleos Vegetais/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Germinação/fisiologia , Folhas de Planta/química , Plântula/química
15.
Am J Bot ; 100(12): 2307-17, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24322894

RESUMO

PREMISE OF THE STUDY: Solanum elaeagnifolium (silverleaf nightshade), having originated in the Americas, is now a serious summer-growing, perennial weed in many countries, including Australia. Most surfaces of the plants have a dense covering of trichomes, giving them a silvery-white appearance, hence the common name. We aimed to identify structural and functional properties of its leaves, especially the trichomes, that may affect the uptake of foliar-applied tracer dyes. METHODS: The structure of leaves of Solanum elaeagnifolium was examined by light and scanning electron microscopy. The potential for transport of materials between trichomes and veins was studied with symplastic (carboxyfluorescein diacetate) and apoplastic (lucifer yellow) tracer dyes. KEY RESULTS: Mature leaves had a dense covering of complex, stellate trichomes on both surfaces, particularly the abaxial. The basal cells of Solanum elaeagnifolium trichomes penetrated into the underlying palisade mesophyll layers. The innermost lobes of these basal cells sometimes contacted the bundle sheath of the veins, but were not observed to directly contact the xylem or phloem. We found that neither symplastic nor apoplastic dyes were transferred between the basal cells of the trichomes and the vascular tissues. The trichome layer repelled water-based tracer dyes, while one of four adjuvants tested facilitated entry of both symplastic and apoplastic dyes. CONCLUSIONS: Our results did not support a transport function for the trichomes. The trichomes may protect the mesophytic leaves from invertebrate herbivory, while also probably decreasing radiation absorbed resulting in cooler leaves in this summer-growing species.


Assuntos
Floema/fisiologia , Folhas de Planta/fisiologia , Transpiração Vegetal , Solanum/fisiologia , Tricomas/fisiologia , Xilema/fisiologia , Austrália , Transporte Biológico , Corantes Fluorescentes , Plantas Daninhas
16.
J Plant Physiol ; 169(17): 1747-53, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22939271

RESUMO

Allelopathic rice cultivar PI312777 (PI) and non-allelopathic rice cultivar Lemont (Le) were mixed with barnyard grass (Echinochloa crus-galli L., BYG) at various ratios (rice:weed ratios of 4:1, 2:1, and 1:1) in hydroponic cultures. The expression of four genes, i.e. phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), ferulic acid 5-hydroxylase (F5H), and caffeic acid O-methyltransferases (COMT), which are involved in the biosynthesis of the phenolic compounds in rice, were evaluated by a quantitative real-time polymerase chain reaction (qRT-PCR). The contents of phenolic compounds in leaves, roots, and culture solutions of the two rice cultivars were determined using high performance liquid chromatography (HPLC). The results showed that all of the four genes were up-regulated in leaves and roots of the allelopathic rice PI at all rice:weed ratios. However, three of the four genes, C4H, F5H, and COMT, were down-regulated in the leaves and roots of the non-allelopathic rice Le. The degree to which PAL was up-regulated in leaves and roots was much higher in PI than in Le. The contents of phenolic compounds in PI leaves, roots, and culture solutions were higher than that in Le leaves, roots, and culture solutions. The higher expression of the genes involved in the phenylpropanoid metabolism and the higher contents of phenolic compounds in PI are consistent with the higher inhibitory rates of PI on BYG. These results indicate that the PAL gene in PI is more sensitive to BYG stress than in Le, and barnyard grass up regulates the biosynthesis of phenolic compound in allelopathic rice.


Assuntos
Echinochloa/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/metabolismo , Fenóis/metabolismo , Proteínas de Plantas/metabolismo , Cromatografia Líquida de Alta Pressão , Hidroponia , Oryza/crescimento & desenvolvimento , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Regulação para Cima
17.
J Chem Ecol ; 35(9): 1129-36, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19787403

RESUMO

In a previous study, lavender (Lavandula spp.) was found to be highly phytotoxic towards annual ryegrass (Lolium rigidum, ARG), a major weed of winter wheat crops in Australia. This research aimed to further explore this relationship and determine the chemical(s) responsible for the observed effect. In bioassay, it was determined that the stem and leaf extract of L. x intermedia cv. Grosso ranked highest and had the potential to reduce significantly the root growth of several plant species. An extract concentration of 10% almost completely inhibited ARG root growth. When the extract was tested for stability, there was no loss in phytotoxicity after the 256 day trial. Via bioassay-guided fractionation and chromatographic techniques, it was determined that the sub-fraction consisting of coumarin and 7-methoxycoumarin was most phytotoxic towards ARG. Chemoassays of 18 structural analogues of coumarin showed that coumarin itself was the most phytotoxic and largely responsible for the observed phytotoxicity of the extract. Soil trials were conducted using pure coumarin and the lavender extract, and in both instances, shoot length and weight were significantly reduced by post-emergence application at all concentrations evaluated.


Assuntos
Herbicidas/química , Lavandula/química , Cumarínicos/química , Cumarínicos/isolamento & purificação , Cumarínicos/toxicidade , Herbicidas/isolamento & purificação , Herbicidas/toxicidade , Lolium/efeitos dos fármacos , Lolium/crescimento & desenvolvimento , Extratos Vegetais/química , Extratos Vegetais/toxicidade , Folhas de Planta/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Caules de Planta/química
19.
Hunan Yi Ke Da Xue Xue Bao ; 28(4): 375-8, 2003 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-14653121

RESUMO

OBJECTIVE: To investigate the main clinical characteristics and genetic analysis of rare chromosome aberration in peripheral blood. METHODS: Peripheral blood cells were cultured for 72 hours with routine method and slids performed, and then the slide was read and mode analysis was carried out. The diagnostic standard of rare chromosomal aberation was: 1-2 abnormal kary types were found in every 30, 60, 200 mitotic phass. RESULTS: The main clinical characteristics of 52 cases of individual chromosomal aberation in peripheral blood included: 1. spontaneous abortion; 2. abnormal sex development; 3. reproduction diseases; and 4. morbid and deformity. CONCLUSION: Rare chromosomal aberation should be regarded as chromosomal diseases. Prenatal diagnosis is necessary for people with such chromosomal aberation in their reproductive actions.


Assuntos
Células Sanguíneas , Aberrações Cromossômicas , Bandeamento Cromossômico , Transtornos Cromossômicos , Aborto Habitual/genética , Adolescente , Adulto , Células Sanguíneas/citologia , Criança , Pré-Escolar , Transtornos Cromossômicos/genética , Análise Citogenética , Feminino , Testes Genéticos/métodos , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade
20.
J Chem Ecol ; 29(10): 2263-79, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14682511

RESUMO

An improved allelopathic correlation between phytotoxicity measured in root growth bioassay upon annual ryegrass (Lolium rigidum Gaud.) and the concentrations of a selection of dynamically produced allelochemicals quantified in the root exudates of cv. Khapli wheat (Triticum turgidum ssp. durum (Desf.) Husn.) monitored during the first 15 days of wheat seedling growth in a sterile, agar-water medium, has been established. Changes over the 15-day growth period in the quantities of five exuded benzoxazinones and seven phenolic acids were measured simultaneously using GC/MS/MS. Substantiating pure compound dose-response measurements were conducted over a range of concentrations for the putative allelochemicals within the wheat exudates. One synergism-based proposal using the monitored compounds to explain the observed low-exudate-concentration phytotoxicity was explored, but was found to be experimentally inadequate.


Assuntos
Lolium/crescimento & desenvolvimento , Triticum/química , Cromatografia Gasosa-Espectrometria de Massas , Fenóis/química , Fenóis/farmacologia , Raízes de Plantas/química , Dinâmica Populacional , Plântula/crescimento & desenvolvimento , Testes de Toxicidade
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