Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Forensic Sci Int ; 275: 160-166, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28366623

RESUMO

Food poisoning is frequently caused by the accidental ingestion of toxic plants that possess strong morphological similarities to edible plants. False helleborine (Veratrum album) is one of the most common plants involved in such accidents. In cases of poisoning by toxic plants, rapid and accurate identification, usually based on the morphological or chemical analysis of plant parts, is required for appropriate medical treatment or forensic investigation. However, morphological examinations require experience in systematic botany because the samples are fragmentary, and chemical analysis of natural compounds can be difficult. In this study, we developed a TaqMan real-time PCR method using trnH-psbA and trnL-trnF that could be carried out in 30-60min. The lower detection limit was less than 10pg of DNA and the primer sets were specific to V. album and Veratrum stamineum. Mixed samples, cooked samples, and simulated gastric contents were successfully identified, and a multiplex assay of two regions was also possible. These results indicate that the TaqMan real-time PCR analysis is a very effective method to detect small samples of V. album and V. stamineum accurately and rapidly in poisoning cases.


Assuntos
Plantas Tóxicas/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Veratrum/genética , DNA de Plantas/genética , Doenças Transmitidas por Alimentos , Humanos , Reação em Cadeia da Polimerase Multiplex/métodos
2.
Int J Legal Med ; 131(1): 1-19, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27796590

RESUMO

Plant exposures are among the most frequently reported cases to poison control centres worldwide. This is a growing condition due to recent societal trends oriented towards the consumption of wild plants as food, cosmetics, or medicine. At least three general causes of plant poisoning can be identified: plant misidentification, introduction of new plant-based supplements and medicines with no controls about their safety, and the lack of regulation for the trading of herbal and phytochemical products. Moreover, an efficient screening for the occurrence of plants poisonous to humans is also desirable at the different stages of the food supply chain: from the raw material to the final transformed product. A rapid diagnosis of intoxication cases is necessary in order to provide the most reliable treatment. However, a precise taxonomic characterization of the ingested species is often challenging. In this review, we provide an overview of the emerging DNA-based tools and technologies to address the issue of poisonous plant identification. Specifically, classic DNA barcoding and its applications using High Resolution Melting (Bar-HRM) ensure high universality and rapid response respectively, whereas High Throughput Sequencing techniques (HTS) provide a complete characterization of plant residues in complex matrices. The pros and cons of each approach have been evaluated with the final aim of proposing a general user's guide to molecular identification directed to different stakeholder categories interested in the diagnostics of poisonous plants.


Assuntos
Plantas Tóxicas/genética , Código de Barras de DNA Taxonômico , DNA de Plantas/genética , Toxicologia Forense , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Reação em Cadeia da Polimerase , Análise de Sequência de DNA
3.
FEBS J ; 282(21): 4141-56, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26260860

RESUMO

Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs.


Assuntos
Conium/enzimologia , Proteínas de Plantas/metabolismo , Policetídeo Sintases/metabolismo , Aciltransferases/classificação , Aciltransferases/genética , Aciltransferases/metabolismo , Alcaloides/biossíntese , Alcaloides/química , Sequência de Aminoácidos , Clonagem Molecular , Conium/genética , Genes de Plantas , Cinética , Redes e Vias Metabólicas , Modelos Biológicos , Dados de Sequência Molecular , Filogenia , Piperidinas/química , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Plantas Tóxicas/enzimologia , Plantas Tóxicas/genética , Policetídeo Sintases/classificação , Policetídeo Sintases/genética , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
4.
PLoS One ; 9(11): e110656, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25365514

RESUMO

Datura stramonium is a widely used poisonous plant with great medicinal and economic value. Its chloroplast (cp) genome is 155,871 bp in length with a typical quadripartite structure of the large (LSC, 86,302 bp) and small (SSC, 18,367 bp) single-copy regions, separated by a pair of inverted repeats (IRs, 25,601 bp). The genome contains 113 unique genes, including 80 protein-coding genes, 29 tRNAs and four rRNAs. A total of 11 forward, 9 palindromic and 13 tandem repeats were detected in the D. stramonium cp genome. Most simple sequence repeats (SSR) are AT-rich and are less abundant in coding regions than in non-coding regions. Both SSRs and GC content were unevenly distributed in the entire cp genome. All preferred synonymous codons were found to use A/T ending codons. The difference in GC contents of entire genomes and of the three-codon positions suggests that the D. stramonium cp genome might possess different genomic organization, in part due to different mutational pressures. The five most divergent coding regions and four non-coding regions (trnH-psbA, rps4-trnS, ndhD-ccsA, and ndhI-ndhG) were identified using whole plastome alignment, which can be used to develop molecular markers for phylogenetics and barcoding studies within the Solanaceae. Phylogenetic analysis based on 68 protein-coding genes supported Datura as a sister to Solanum. This study provides valuable information for phylogenetic and cp genetic engineering studies of this poisonous and medicinal plant.


Assuntos
Datura stramonium/genética , Genoma de Cloroplastos , Plantas Medicinais/genética , Plantas Tóxicas/genética , Composição de Bases , Códon , Biologia Computacional , Datura stramonium/classificação , Engenharia Genética , Genômica , Repetições de Microssatélites , Anotação de Sequência Molecular , Filogenia , Plantas Medicinais/classificação , Plantas Tóxicas/classificação , Sequências Repetitivas de Ácido Nucleico , Análise de Sequência de DNA
5.
Biomed Environ Sci ; 27(10): 794-806, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25341815

RESUMO

OBJECTIVE: Poisonous plants are a deadly threat to public health in China. The traditional clinical diagnosis of the toxic plants is inefficient, fallible, and dependent upon experts. In this study, we tested the performance of DNA barcodes for identification of the most threatening poisonous plants in China. METHODS: Seventy-four accessions of 27 toxic plant species in 22 genera and 17 families were sampled and three DNA barcodes (matK, rbcL, and ITS) were amplified, sequenced and tested. Three methods, Blast, pairwise global alignment (PWG) distance, and Tree-Building were tested for discrimination power. RESULTS: The primer universality of all the three markers was high. Except in the case of ITS for Hemerocallis minor, the three barcodes were successfully generated from all the selected species. Among the three methods applied, Blast showed the lowest discrimination rate, whereas PWG Distance and Tree-Building methods were equally effective. The ITS barcode showed highest discrimination rates using the PWG Distance and Tree-Building methods. When the barcodes were combined, discrimination rates were increased for the Blast method. CONCLUSION: DNA barcoding technique provides us a fast tool for clinical identification of poisonous plants in China. We suggest matK, rbcL, ITS used in combination as DNA barcodes for authentication of poisonous plants.


Assuntos
Código de Barras de DNA Taxonômico/normas , DNA Intergênico/genética , Proteínas de Plantas/genética , Plantas Tóxicas/classificação , Plantas Tóxicas/genética , China , Primers do DNA/genética , Ribulose-Bifosfato Carboxilase/genética , Análise de Sequência de DNA , Especificidade da Espécie
6.
Plant Physiol Biochem ; 49(10): 1183-90, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21835630

RESUMO

Jatropha curcas L. has been promoted as an oilseed crop for use to meet the increased world demand for vegetable oil production, and in particular, as a feedstock for biodiesel production. Seed meal is a protein-rich by-product of vegetable oil extraction, which can either be used as an organic fertilizer, or converted to animal feed. However, conversion of J. curcas seed meal into animal feed is complicated by the presence of toxins, though plants producing "edible" or "non-toxic" seeds occur in Mexico. Toxins present in the seeds of J. curcas include phorbol esters and a type-I ribosome inactivating protein (curcin). Although the edible seeds of J. curcas are known to lack phorbol esters, the curcin content of these seeds has not previously been studied. We analyzed the phorbol ester and curcin content of J. curcas seeds obtained from Mexico and Madagascar, and conclude that while phorbol esters are lacking in edible seeds, both types contain curcin. We also analyzed spatial distribution of these toxins in seeds. Phorbol-esters were most concentrated in the tegmen. Curcin was found in both the endosperm and tegmen. We conclude that seed toxicity in J. curcas is likely to be due to a monogenic trait, which may be under maternal control. We also conducted AFLP analysis and conclude that genetic diversity is very limited in the Madagascan collection compared to the Mexican collection.


Assuntos
Jatropha/química , Ésteres de Forbol/análise , Plantas Tóxicas/química , Proteínas Inativadoras de Ribossomos Tipo 1/análise , Sementes/química , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , DNA de Plantas/genética , DNA de Plantas/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Escherichia coli/genética , Escherichia coli/metabolismo , Variação Genética , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Jatropha/genética , Madagáscar , México , Ésteres de Forbol/química , Plantas Comestíveis/química , Plantas Comestíveis/genética , Plantas Tóxicas/genética , Proteínas Inativadoras de Ribossomos Tipo 1/química , Sementes/genética
7.
Biochem J ; 436(2): 371-85, 2011 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-21388347

RESUMO

Ricin is a potent plant cytotoxin composed of an A-chain [RTA (ricin A-chain)] connected by a disulfide bond to a cell binding lectin B-chain [RTB (ricin B-chain)]. After endocytic uptake, the toxin is transported retrogradely to the ER (endoplasmic reticulum) from where enzymatically active RTA is translocated to the cytosol. This transport is promoted by the EDEM1 (ER degradation-enhancing α-mannosidase I-like protein 1), which is also responsible for directing aberrant proteins for ERAD (ER-associated protein degradation). RTA contains a 12-residue hydrophobic C-terminal region that becomes exposed after reduction of ricin in the ER. This region, especially Pro250, plays a crucial role in ricin cytotoxicity. In the present study, we introduced a point mutation [P250A (substitution of Pro250 with alanine)] in the hydrophobic region of RTA to study the intracellular transport of the modified toxin. The introduced mutation alters the secondary structure of RTA into a more helical structure. Mutation P250A increases endosomal-lysosomal degradation of the toxin, as well as reducing its transport from the ER to the cytosol. Transport of modified RTA to the cytosol, in contrast to wild-type RTA, appears to be EDEM1-independent. Importantly, the interaction between EDEM1 and RTA(P250A) is reduced. This is the first reported evidence that EDEM1 protein recognition might be determined by the structure of the ERAD substrate.


Assuntos
Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/metabolismo , Plantas Tóxicas/toxicidade , Mutação Puntual/genética , Ricina/genética , Ricina/toxicidade , Animais , Retículo Endoplasmático/genética , Células HEK293 , Humanos , Proteínas de Membrana/genética , Plantas Tóxicas/genética , Plantas Tóxicas/metabolismo , Dobramento de Proteína , Transporte Proteico/genética , Ricina/metabolismo , Especificidade por Substrato , Toxinas Biológicas/genética , Toxinas Biológicas/metabolismo , Células Vero
8.
Int J Legal Med ; 125(2): 211-7, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20623131

RESUMO

Some plants have toxicities that are dangerous for humans. In the case of poisoning by toxic plants, a rapid and easy screening test is required for accurate medical treatment or forensic investigation. In this study, we designed specific primer pairs for identification of toxic plants, such as subgenus Aconitum, genus Ricinus, genus Illicium, and genus Scopolia, by internal transcribed spacer sequences of nuclear ribosomal DNA. Allied species of target plants, foods, and human DNA were not detected, but each primer pair provided a specific PCR product from the target plant using real-time PCR. This method can detect the subgenus Aconitum, genus Ricinus, and genus Scopolia with template DNA of 10 pg, respectively, and genus Illicium with 1 pg. Furthermore, each primer pair provided the exact PCR product from digested target plants in artificial gastric fluid. When a trace unknown plant sample in forensic investigation is collected from stomach contents, this PCR assay may be useful for screening toxic plants.


Assuntos
DNA de Plantas/análise , Plantas Tóxicas/genética , Reação em Cadeia da Polimerase/métodos , Aconitum/classificação , Aconitum/genética , Aconitum/toxicidade , Primers do DNA , DNA de Plantas/genética , DNA Espaçador Ribossômico/genética , Humanos , Illicium/classificação , Illicium/genética , Illicium/toxicidade , Plantas Tóxicas/classificação , Plantas Tóxicas/toxicidade , RNA Nuclear/análise , Ricinus/classificação , Ricinus/genética , Ricinus/toxicidade , Scopolia/classificação , Scopolia/genética , Scopolia/toxicidade
9.
Int J Legal Med ; 124(6): 595-603, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20354712

RESUMO

The plant exposures are one of the most frequent poisonings reported to poison control centres. The diagnosis of intoxicated patients is usually based on the morphological analysis of ingested plant portions; this procedure requires experience in systematic botany, because the plant identification is based on few evident traits. The objective of this research is to test DNA barcoding approach as a new universal tool to identify toxic plants univocally and rapidly. Five DNA barcode regions were evaluated: three cpDNA sequences (trnH-psbA, rpoB and matK) and two nuclear regions (At103 and sqd1). The performance of these markers was evaluated in three plant groups: (1) a large collection of angiosperms containing different toxic substances, (2) congeneric species showing different degrees of toxicity and (3) congeneric edible and poisonous plants. Based on assessments of PCR, sequence quality and resolution power in species discrimination, we recommend the combination of plastidial and nuclear markers to identify toxic plants. Concerning plastidial markers, matK and trnH-psbA showed consistent genetic variability. However, in agreement with CBOL Plant Working Group, we selected matK as the best marker, because trnH-psbA showed some problems in sequences sizes and alignments. As a final and relevant observation, we also propose the combination of matK with a nuclear marker such as At103 to distinguish toxic hybrids form parental species. In conclusion, our data support the claim that DNA barcoding is a powerful tool for poisonous plant identifications.


Assuntos
Código de Barras de DNA Taxonômico/métodos , DNA de Plantas/classificação , Genética Forense/métodos , Plantas Tóxicas/classificação , Plantas Tóxicas/genética , DNA de Plantas/genética , Marcadores Genéticos , Técnicas de Amplificação de Ácido Nucleico , Proteínas de Plantas/análise , Alinhamento de Sequência , Especificidade da Espécie
10.
Planta Med ; 75(4): 392-5, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19145553

RESUMO

Chinese Star anise, Illicium verum Hook, is a well known spice in many cultures and has also been used to treat infant colic. Recent publications report that Chinese Star anise might be adulterated with the toxic Japanese Star anise, Illicium anisatum L. We have developed a molecular method that helps with the detection of I. anisatum as adulterant of I. verum. We PCR-amplified the internal transcribed spacer (ITS) region and analyzed it with the endonucleases PSTI and BFMI. Based on fragment length polymorphisms (RFLP), we were able to detect and distinguish between I. anisatum and other Illicium species in powdered samples.


Assuntos
Illicium/classificação , Illicium/genética , Plantas Tóxicas/classificação , Plantas Tóxicas/genética , Sequência de Bases , DNA Intergênico/genética , DNA de Plantas/genética , Contaminação de Alimentos , Especificidade da Espécie
11.
Vaccine ; 25(42): 7459-69, 2007 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-17875350

RESUMO

Ricin is a plant toxin that is a CDC level B biothreat. Our recombinant ricin A chain vaccine (RiVax), which contains mutations in both known toxic sites, has no residual toxicity at doses at least 800 times the immunogenic dose. RiVax without adjuvant given intramuscularly (i.m.) protected mice against intraperitoneally administered ricin. Furthermore the vaccine without alum was safe and immunogenic in human volunteers. Here we describe the development of gavage and aerosol ricin challenge models in mice and demonstrate that i.m. vaccination protects mice against ricin delivered by either route. Also RiVax protects against aerosol-induced lung damage as determined by histology and lung function tests.


Assuntos
Ricina/antagonistas & inibidores , Vacinas Sintéticas/administração & dosagem , Administração por Inalação , Administração Oral , Aerossóis , Animais , Bioterrorismo , Genes de Plantas , Humanos , Injeções Intramusculares , Intestinos/efeitos dos fármacos , Intestinos/patologia , Dose Letal Mediana , Pulmão/efeitos dos fármacos , Pulmão/patologia , Pulmão/fisiopatologia , Camundongos , Mutação , Plantas Tóxicas/genética , Ricina/genética , Ricina/imunologia , Ricina/toxicidade , Ricinus/genética , Vacinas
12.
Forensic Sci Int Genet ; 1(3-4): 262-6, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19083771

RESUMO

Here, we show a new, simple, and rapid SYBR Green-based Real-Time PCR assay for the quantification of hallucinogenic plants in plant mixtures. As a test plant, Salvia divinorum Epling & Játiva-M., a perennial herb belonging to the Lamiaceae family able to induce hallucinations, changes in perception, or other psychologically induced changes with similar potency as LSD, was used. The method was tested on seven mixtures 100/0%, 80/20%, 60/40%, 40/60%, 20/80%, 10/90%, 0/100% (w/w) S. divinorum versus a non-hallucinogenic plant, Salvia officinalis. Total DNA was extracted from samples and quantified by Real-Time PCR. Arabidopsis thaliana genomic DNA was added, as internal standard, at the beginning of each extraction. A new formula for the interpretation of Real-Time PCR data, based on the relative quantification of DNA extracted from mixture versus a reference DNA extracted from a known amount of pure S. divinorum, was developed. The results of this work show an almost perfect correspondence between Real-Time PCR-calculated weight and the weight estimated by an analytical weighted method, proving the effectiveness of this method for the quantitative analysis of a given species in a plant mixture.


Assuntos
DNA de Plantas/genética , DNA de Plantas/normas , Alucinógenos , Plantas Tóxicas/genética , Arabidopsis/genética , Sequência de Bases , Primers do DNA/genética , Genética Forense/métodos , Genética Forense/estatística & dados numéricos , Modelos Estatísticos , Plantas Tóxicas/toxicidade , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/estatística & dados numéricos , Padrões de Referência , Salvia/genética , Salvia/toxicidade
13.
J Virol ; 80(7): 3624-33, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16537630

RESUMO

A versatile green fluorescent protein (GFP) expression cassette containing the replication origins of the monopartite begomovirus Tomato yellow leaf curl Sardinia virus (TYLCSV) is described. Transgenic Nicotiana benthamiana plants containing one copy of the cassette stably integrated into their genome were superinfected with TYLCSV, which mobilized and replicated the cassette as an episomal replicon. The expression of the reporter gene (the GFP gene) was thereby modified. Whereas GFP fluorescence was dimmed in the intercostal areas, an increase of green fluorescence in veins of all leaves placed above the inoculation site, as well as in transport tissues of roots and stems, was observed. The release of episomal trans replicons from the transgene and the increase in GFP expression were dependent on the cognate geminiviral replication-associated protein (Rep) and required interaction between Rep and the intergenic region of TYLCSV. This expression system is able to monitor the replication status of TYLCSV in plants, as induction of GFP expression is only produced in those tissues where Rep is present. To further confirm this notion, the expression of a host factor required for geminivirus replication, the proliferating cellular nuclear antigen (PCNA) was transiently silenced. Inhibition of PCNA prevented GFP induction in veins and reduced viral DNA. We propose that these plants could be widely used to easily identify host factors required for geminivirus replication by virus-induced gene silencing.


Assuntos
Geminiviridae/fisiologia , Proteínas de Plantas/metabolismo , Proteínas Virais/metabolismo , Replicação Viral , DNA Viral/genética , Geminiviridae/genética , Geminiviridae/metabolismo , Geminiviridae/patogenicidade , Inativação Gênica , Genes de Plantas , Genes Reporter , Genoma de Planta , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/metabolismo , Cinética , Folhas de Planta/virologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Plantas Tóxicas/genética , Plantas Tóxicas/virologia , Plasmídeos , Antígeno Nuclear de Célula em Proliferação/metabolismo , Replicon , Tabaco/genética , Tabaco/virologia , Transgenes , Proteínas Virais/genética
14.
Acta Biochim Biophys Sin (Shanghai) ; 36(4): 309-13, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15253158

RESUMO

The wild-type Cry1Ie gene from Bacillus thuringiensis was modified for its efficient expression in transgenic plants. Modified Cry1Ie gene (designated as Cry1Iem) was cloned into prokaryotic expression vector pET28b and its expression in E. coli was confirmed by SDS-PAGE analysis. Bioassays using crude expression products in E. coli revealed that Cry1Iem protein had a similar toxicity to corn borer as wild-type Cry1Ie. Cry1Iem gene was then inserted downstream of the maize ubiquitin-1 promoter in plant expression vector p3301. Transgenic tobacco plants carrying Cry1Iem showed insecticidal activity against corn borer.


Assuntos
Escherichia coli/genética , Genes Bacterianos , Controle Biológico de Vetores , Plantas Tóxicas/genética , Tabaco/genética , Zea mays/genética , Zea mays/parasitologia , Animais , Bacillus thuringiensis/genética , Eletroforese em Gel de Poliacrilamida , Regulação da Expressão Gênica de Plantas , Insetos , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Ubiquitina/genética , Ubiquitina/metabolismo , Zea mays/metabolismo
15.
Biotechnol Appl Biochem ; 39(Pt 3): 355-61, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15154849

RESUMO

A transient gene-expression system was developed and used to characterize promoter strength, to verify suitability of bacterial gene modifications for expression in plant cells, and to express active antibody molecules. The system is based on suspension tobacco cells transformed by Agrobacterium in a transient way. Conditions such as pre-culture of tobacco cells and the co-cultivation period were identified as determinants to achieve high expression levels. Under established conditions the activity strength of CaMV (cauliflower mosaic virus) 35 S and ToMoTV (tomato mottle taino virus) AL1 promoters were compared. A modified cry gene sequence from Bacillus thuringiensis was expressed and detected by Western-blot analysis. A monoclonal antibody against anti-(hepatitis B virus surface antigen) was produced in such quantities as to allow testing of biological activity and preliminary characterization.


Assuntos
Agrobacterium tumefaciens/genética , Plantas Tóxicas/genética , Regiões Promotoras Genéticas , Tabaco/genética , Transformação Genética , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Antígenos Virais/imunologia , Bacillus thuringiensis/genética , Western Blotting , Caulimovirus/genética , Células Cultivadas , Técnicas de Cocultura , Regulação Viral da Expressão Gênica , Genes Bacterianos , Glucuronidase/genética , Glucuronidase/metabolismo , Antígenos de Superfície da Hepatite B/biossíntese , Antígenos de Superfície da Hepatite B/genética , Antígenos de Superfície da Hepatite B/imunologia , Lycopersicon esculentum/virologia , Plantas Geneticamente Modificadas/virologia , Plantas Tóxicas/citologia , Recombinação Genética , Tabaco/citologia
16.
Shi Yan Sheng Wu Xue Bao ; 36(3): 176-84, 2003 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-12966726

RESUMO

In previous study, we have proved that the resistance of the transgenic tobacco plants containing untranslatable PVYN CP gene was mediated by PVYN CP transgene RNAs, and the resistance mechanism was similar to PTGS. In this paper, T0 progeny transgenic lines with different resistant levels were selected to further study the transgene inheritance and resistant stability of transgenic plants. Results showed that T0 progeny susceptible lines, which contained 1-2 transgene copies, displayed a 3:1 segregation ratio in T1 progeny lines; T0 progeny middle resistant lines, which contained 3-4 transgene copies, revealed a 15:1 segergation ratio in T1 progeny lines; T0 progeny highly resistant lines, which contained 5-7 transgene copies, followed 15:1 or 63:1 segregation pattern in T1 progeny lines. Southern blot analysis revealed the resistance in most T1 and T2 progeny transgenic lines was related to copy numbers of the transgene. Northern blot analysis indicated that PVYN CP transgenes were expressed at transcription level in most T1 and T2 progeny transgenic lines, and the transgene mRNA accumulation in cytoplasm varied among transgenic lines. There was an inverse correlation between transgene transcript accumulation and virus resistance. Resistance of transgenic lines was inheritable over at least two generations, and the resistance of T2 progeny transgenic lines, which containing untranslatable PVYN CP gene, was (1) not overcome by PVYN particle or PVYN RNA; (2) independent of inoculum levels; (3) resistant to either aphid or mechanically transmitted PVYN; (4) not dependent on plant development stages; (5) PVY-specific (i.e., broad-spectrum resistance was not observed).


Assuntos
Proteínas do Capsídeo/genética , Plantas Geneticamente Modificadas/genética , Potyvirus/patogenicidade , RNA Viral/metabolismo , Tabaco/genética , Proteínas do Capsídeo/fisiologia , Clonagem Molecular , Regulação Viral da Expressão Gênica , Doenças das Plantas/virologia , Vírus de Plantas/genética , Plantas Geneticamente Modificadas/virologia , Plantas Tóxicas/genética , Plantas Tóxicas/virologia , Potyvirus/genética , Biossíntese de Proteínas , RNA , Processamento Pós-Transcricional do RNA , RNA Viral/genética , Tabaco/virologia
17.
Am Nat ; 161(4): 507-22, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12776881

RESUMO

Literature data were collected on the floristic distribution and toxicity of phytochemicals to herbivores and on herbivore specialization in order to test phytochemical coevolution theory. The theory makes four predictions that can be tested with this information. Herbivores can adapt to novel, more toxic chemicals by becoming specialists, or they can become generalists but at the cost of lower feeding success on any particular host. Thus, the first two predictions are as follows: herbivores should do better on chemicals that are present in their normal host, and this pattern should be stronger for specialists than for generalists. The "escape and radiation" aspect of the theory holds that if a plant taxon with a novel defense chemical diversifies, the chemical will become widespread. Eventually, herbivores will adapt to and disarm it. So the third prediction is that more widespread chemicals are less toxic than more narrowly distributed ones. Because generalists should not do as well as specialists on chemicals disarmed by the latter, the fourth prediction is that the third prediction should be more true for generalists than specialists and should depend on presence/absence of the chemical in the normal host. Multiple regressions of toxicity (herbivore mortality and final weight) on three predictor variables (chemical presence/absence in the normal host, specialism, and chemical floristic distribution) and relevant interactions were used to test these predictions. Chemical presence/absence in the normal host, the interaction between this variable and specialism, and chemical floristic distribution had significant effects on both measures of toxicity, supporting the first three predictions of the model. Support for the fourth prediction (a three-way interaction among all predictor variables) was evident for final weight but not mortality, perhaps because growth is more responsive to toxicity differences than survival. In short, the phytochemistry literature provides broad support for the phytochemical coevolution model.


Assuntos
Evolução Biológica , Comportamento Alimentar/fisiologia , Insetos/fisiologia , Modelos Biológicos , Plantas Tóxicas/química , Adaptação Fisiológica , Animais , Inativação Metabólica , Análise Multivariada , Plantas Tóxicas/genética , Plantas Tóxicas/toxicidade , Especificidade da Espécie
19.
Parasitology ; 106 Suppl: S47-53, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8488071

RESUMO

Only green plants can convert the single carbon units of atmospheric carbon dioxide into the multi-carbon organic molecules on which all forms of life depend. Only green plants can provide the oxygen required by man and other aerobic organisms. In addition to his basic need for preformed organic molecules and oxygen, man also depends on plants to provide him, directly or indirectly, with an array of specific compounds such as vitamins and essential amino acids. Inadequate supplies of these may hinder growth and development or give rise to well defined deficiency diseases. At the present time information concerning the distribution and concentrations of such essential nutrients in plants is largely restricted to those plants that are already used as human foods. Nothing or virtually nothing is known about the chemical composition of approximately 250 000 wild and little-used species. Amongst these there may be many that could provide us with cheap and plentiful new sources of essential nutrients that could be of enormous benefit to those suffering not only from full-blown deficiency diseases but also suffering sub-normal health due to partial deficiencies. The destruction of much of the world's wilderness areas has already deprived us of the opportunity to evaluate the contributions that a great many plant species might have made towards the elimination of deficiency diseases. Many plants used as human foods contain compounds that are toxic to man. If intake is sufficiently high, these toxins may cause disease. Breeding programmes designed to eliminate toxins from crops species or reduce their concentrations to acceptable levels depend on genetic variability within the species or the possibility of producing hybrids with the desired characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Conservação dos Recursos Naturais , Intoxicação por Plantas/etiologia , Plantas Comestíveis , Plantas Medicinais , Plantas Tóxicas , Animais , Variação Genética , Humanos , Plantas Comestíveis/genética , Plantas Medicinais/genética , Plantas Tóxicas/genética
20.
Australas J Dermatol ; 30(2): 111-3, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2486171

RESUMO

Of the 250 or so species of Grevillea, a small number of these species (within a specific section of the genus) and their associated hybrids have been recorded as causing contact dermatitis. A brief historical survey of the occurrence of contact dermatitis and the species responsible is given. Attention is drawn to the associated species, about which at the present time no information is available regarding their possible effect on man. Because one of the hybrids, G.x "Robyn Gordon" is an extremely popular garden plant which has been widely planted in various sites, attention is drawn to the likely trouble it may cause to those who come into actual contact with it.


Assuntos
Dermatite de Contato/etiologia , Plantas Tóxicas , Austrália , Humanos , Hibridização Genética , Plantas Tóxicas/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA