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1.
Plants (Basel) ; 10(11)2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34834696

RESUMO

In the current context of climate change, plants need to develop different mechanisms of stress tolerance and adaptation to cope with changing environmental conditions. Temperature is one of the most important abiotic stresses that forest trees have to overcome. Recent research developed in our laboratory demonstrated that high temperatures during different stages of conifer somatic embryogenesis (SE) modify subsequent phases of the process and the behavior of the resulting ex vitro somatic plants. For this reason, Aleppo pine SE was induced under different heat stress treatments (40 °C for 4 h, 50 °C for 30 min, and 60 °C for 5 min) in order to analyze its effect on the global DNA methylation rates and the differential expression of four stress-related genes at different stages of the SE process. Results showed that a slight decrease of DNA methylation at proliferating embryonal masses (EMs) can correlate with the final efficiency of the process. Additionally, different expression patterns for stress-related genes were found in EMs and needles from the in vitro somatic plants obtained; the DEHYDRATION INDUCED PROTEIN 19 gene was up-regulated in response to heat at proliferating EMs, whereas HSP20 FAMILY PROTEIN and SUPEROXIDE DISMUTASE [Cu-Zn] were down-regulated in needles.

2.
Plants (Basel) ; 10(8)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34451613

RESUMO

Arbutus unedo L. is a resilient tree with a circum-Mediterranean distribution. Besides its ecological relevance, it is vital for local economies as a fruit tree. Several microorganisms are responsible for strawberry tree diseases, leading to production constrictions. Thus, the development of alternative plant protection strategies is necessary, such as bacterial endophytes, which may increase their host's overall fitness and productivity. As agricultural practices are a driving factor of microbiota, this paper aimed to isolate, identify and characterize endophytic bacteria from strawberry tree leaves from plants growing spontaneously in a natural environment as well as from plants growing in orchards. A total of 62 endophytes were isolated from leaves and identified as Bacillus, Paenibacillus, Pseudomonas, Sphingomonas and Staphylococcus. Although a slightly higher number of species was found in wild plants, no differences in terms of diversity indexes were found. Sixteen isolates were tested in vitro for their antagonistic effect against A. unedo mycopathogens. B. cereus was the most effective antagonist causing a growth reduction of 20% in Glomerella cingulata and 40% in Phytophthora cinnamomi and Mycosphaerella aurantia. Several endophytic isolates also exhibited plant growth-promoting potential. This study provides insights into the diversity of endophytic bacteria in A. unedo leaves and their potential role as growth promoters and pathogen antagonists.

3.
Front Plant Sci ; 12: 679966, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34276732

RESUMO

Arundo donax, Cortaderia selloana and Phragmites australis are high-biomass-producing perennial Poalean species that grow abundantly and spontaneously in warm temperate regions, such as in Mediterranean-type climates, like those of Southern Europe, Western United States coastal areas, or in regions of South America, South Africa and Australia. Given their vigorous and spontaneous growth, biomass from the studied grasses often accumulates excessively in unmanaged agro-forestry areas. Nonetheless, this also creates the demand and opportunity for the valorisation of these biomass sources, particularly their cell wall polymers, for biorefining applications. By contrast, a related crop, Miscanthus × giganteus, is a perennial grass that has been extensively studied for lignocellulosic biomass production, as it can grow on low-input agricultural systems in colder climates. In this study Fourier transform mid-infrared spectroscopy (FTIR), high-performance anion-exchange chromatography (HPAEC) and lignin content determinations were used for a comparative compositional characterisation of A. donax, C. selloana and P. australis harvested from the wild, in relation to a trial field-grown M. × giganteus high-yielding genotype. A high-throughput saccharification assay showed relatively high sugar release values from the wild-grown grasses, even with a 0.1M NaOH mild alkali pretreatment. In addition to this alkaline pretreatment, biomass was treated with white-rot fungi (WRF), which preferentially degrade lignin more readily than holocellulose. Three fungal species were used: Ganoderma lucidum, Pleurotus ostreatus and Trametes versicolor. Our results showed that neutral sugar contents are not significantly altered, while some lignin is lost during the pretreatments. Furthermore, sugar release upon enzymatic saccharification was enhanced, and this was dependent on the plant biomass and fungal species used in the treatment. To maximise the potential for lignocellulose valorisation, the liquid fractions from the pretreatments were analysed by high performance liquid chromatography - photodiode array detection - electrospray ionisation tandem mass spectrometry (HPLC-PDA-ESI-MS n ). This study is one of the first to report on the composition of WRF-treated grass biomass, while assessing the potential relevance of breakdown products released during the treatments, beyond more traditional sugar-for-energy applications. Ultimately, we expect that our data will help promote the valorisation of unused biomass resources, create economic value, while contributing to the implementation of sustainable biorefining systems.

4.
Protoplasma ; 2021 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-34282477

RESUMO

Strawberry tree (Arbutus unedo, Ericaceae) is an evergreen tree with a circum-Mediterranean distribution. It has a great ecological and economic importance as a source of bioactive compounds with industrial applications and for fruit production. This study aims to characterize the fungi microbiome of this forestry species in order to develop biological control strategies in the increasing orchard production area. For this purpose, fungi endophytes were isolated from wild strawberry tree plants, and a molecular identification was carried out. In vitro assays were carried out to evaluate and characterize the antagonism of some endophytes. Among the several fungi endophytes isolated from strawberry tree (a total of 53 from 20 genera), a Trichoderma atroviride strain proved to have antagonism effect against several phytopathogens, including Alternaria alternata, Botrytis cinerea, Glomerella cingulata, and Mycosphaerella aurantia. This antagonism was particularly effective against Phytophthora cinnamomi, causing a reduction in growth of about 80% on this invasive oomycete. An enzymatic assay revealed the production of several enzymes by T. atroviride, such as cellulases, chitinases, glucosidases, alkaline phosphatases, and proteases, which is one of the several mechanisms known to be involved on Trichoderma biological control ability. The enzymatic activity, in particular that of cell wall-degrading enzymes, was accentuated when in a dual culture with P. cinnamomi. The production of serine proteases, aspartyl proteases, metalloproteases, and cysteine proteases was also detected in an experiment carried out in liquid medium, suggesting the involvement of these proteases on Trichoderma mycoparasitism mechanisms. Finally, in a three-way interaction with in vitro strawberry tree plants, the T. atroviride strain identified on this study (Au50) was able to protect the plants against P. cinnamomi, thus proving its potential as a biological control agent.

5.
Plants (Basel) ; 10(6)2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34198660

RESUMO

Ethylene is a plant hormone controlling physiological and developmental processes such as fruit maturation, hairy root formation, and leaf abscission. Its effect on regeneration systems, such as organogenesis and somatic embryogenesis (SE), has been studied, and progress in molecular biology techniques have contributed to unveiling the mechanisms behind its effects. The influence of ethylene on regeneration should not be overlooked. This compound affects regeneration differently, depending on the species, genotype, and explant. In some species, ethylene seems to revert recalcitrance in genotypes with low regeneration capacity. However, its effect is not additive, since in genotypes with high regeneration capacity this ability decreases in the presence of ethylene precursors, suggesting that regeneration is modulated by ethylene. Several lines of evidence have shown that the role of ethylene in regeneration is markedly connected to biotic and abiotic stresses as well as to hormonal-crosstalk, in particular with key regeneration hormones and growth regulators of the auxin and cytokinin families. Transcriptional factors of the ethylene response factor (ERF) family are regulated by ethylene and strongly connected to SE induction. Thus, an evident connection between ethylene, stress responses, and regeneration capacity is markedly established. In this review the effect of ethylene and the way it interacts with other players during organogenesis and somatic embryogenesis is discussed. Further studies on the regulation of ERF gene expression induced by ethylene during regeneration can contribute to new insights on the exact role of ethylene in these processes. A possible role in epigenetic modifications should be considered, since some ethylene signaling components are directly related to histone acetylation.

6.
Front Plant Sci ; 12: 631239, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33912202

RESUMO

Somatic embryogenesis is the process by which bipolar structures with no vascular connection with the surrounding tissue are formed from a single or a group of vegetative cells, and in conifers it can be divided into five different steps: initiation, proliferation, maturation, germination and acclimatization. Somatic embryogenesis has long been used as a model to study the mechanisms regulating stress response in plants, and recent research carried out in our laboratory has demonstrated that high temperatures during initial stages of conifer somatic embryogenesis modify subsequent phases of the process, as well as the behavior of the resulting plants ex vitro. The development of high-throughput techniques has facilitated the study of the molecular response of plants to numerous stress factors. Proteomics offers a reliable image of the cell status and is known to be extremely susceptible to environmental changes. In this study, the proteome of radiata pine somatic embryos was analyzed by LC-MS after the application of high temperatures during initiation of embryonal masses [(23°C, control; 40°C (4 h); 60°C (5 min)]. At the same time, the content of specific soluble sugars and sugar alcohols was analyzed by HPLC. Results confirmed a significant decrease in the initiation rate of embryonal masses under 40°C treatments (from 44 to 30.5%) and an increasing tendency in the production of somatic embryos (from 121.87 to 170.83 somatic embryos per gram of embryogenic tissue). Besides, heat provoked a long-term readjustment of the protein synthesis machinery: a great number of structural constituents of ribosomes were increased under high temperatures, together with the down-regulation of the enzyme methionine-tRNA ligase. Heat led to higher contents of heat shock proteins and chaperones, transmembrane transport proteins, proteins related with post-transcriptional regulation (ARGONAUTE 1D) and enzymes involved in the synthesis of fatty acids, specific compatible sugars (myo-inositol) and cell-wall carbohydrates. On the other hand, the protein adenosylhomocysteinase and enzymes linked with the glycolytic pathway, nitrogen assimilation and oxidative stress response were found at lower levels.

7.
Spectrochim Acta A Mol Biomol Spectrosc ; 252: 119501, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33571737

RESUMO

Tamarillo (tree tomato) is a subtropical tree that produces edible fruits with health-beneficial properties, since it contains several components with potential therapeutic and chemoprotective activity. The present work reports the first complete vibrational study (Raman and infrared) of this edible fruit. This approach allowed us to determine where the most relevant nutraceutical compounds are located in the fruit, as well as their relative amounts. Particular vibrational signatures were obtained for each part of the fruit, reporting different components for the epicarp (outer and inner sections), the pulp and the seeds, especially regarding the content in phenolic compounds, unsaturated fatty acids/esters and polymeric chains from the cuticular wax. Valuable information, at the molecular level was gathered regarding the nutricional value of tamarillo's fruit, for its different fractions. This is expected to pave the way for its introduction as a promising nutraceutical, based on the potential therapeutic properties of its main components.


Assuntos
Suplementos Nutricionais , Frutas , Fenóis , Frutas/química , Fenóis/análise , Vibração
8.
Front Plant Sci ; 10: 438, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31024602

RESUMO

Somatic embryogenesis (SE) is an important biotechnological tool for large-scale clonal propagation and for embryogenesis research. Moreover, genetic transformation and cryopreservation procedures in many species rely on efficient SE protocols. We have been studying different aspects related to SE induction and somatic embryo development in tamarillo (Solanum betaceum Cav.), a small tree from the Solanaceae family. Previous proteomic analyses identified a protein (NEP-TC, 26.5 kDa) consistently present in non-embryogenic calluses of tamarillo, but absent in the embryogenic ones. In this work, the role of NEP-TC during SE was assessed by gene expression analysis and immunolocalization. The results obtained demonstrated that NEP-TC is a putative member of the SpoU rRNA methylase family. This protein, present in the cytoplasm and nucleus, is expressed in non-embryogenic cells and not expressed in embryogenic cells. Slightly enhanced SE induction levels in tamarillo plants with NEP-TC down-regulated levels also supports the role of this protein on SE induction. Heterologous expression was used to confirm NEP-TC rRNA methyltransferase activity, with enhanced activity levels when rRNA was used as a substrate. These data relate a putative member of the SpoU methylase family with plant morphogenesis, in particular with SE induction.

9.
Methods Mol Biol ; 1359: 117-29, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26619861

RESUMO

Proteomic approaches have been used to understand several regulatory aspects of plant development. Somatic embryogenesis is one of those developmental pathways that have beneficiated from the integration of proteomics data to the understanding of the molecular mechanisms that control embryogenic competence acquisition, somatic embryo development and conversion into viable plants. Nevertheless, most of the results obtained are based on the traditional model systems, very often not easily compared with the somatic embryogenesis systems of economical relevant woody species. The aim of this work is to summarize some of the applications of proteomics in the understanding of particular aspects of the somatic embryogenesis process in broad-leaf woody plants (model and non-model systems).


Assuntos
Desenvolvimento Vegetal/genética , Técnicas de Embriogênese Somática de Plantas/métodos , Plantas/genética , Proteômica/métodos , Apoptose/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética
10.
Methods Mol Biol ; 1359: 329-39, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26619869

RESUMO

Somatic embryogenesis is a powerful tool both for cloning and studies of genetic transformation and embryo development. Most protocols for somatic embryogenesis induction start from zygotic embryos or embryonic-derived tissues which do not allow the propagation of elite trees. In the present study, a reliable protocol for somatic embryogenesis induction from adult trees of strawberry tree is described. Leaves from in vitro proliferating shoots were used to induce somatic embryo formation on a medium containing an auxin and a cytokinin. Somatic embryos germinated in a plant growth regulator-free medium.


Assuntos
Fragaria/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Técnicas de Embriogênese Somática de Plantas/métodos , Técnicas de Cultura de Tecidos/métodos , Fragaria/genética , Frutas/genética , Frutas/crescimento & desenvolvimento , Desenvolvimento Vegetal/genética , Brotos de Planta/genética , Plantas Geneticamente Modificadas/genética , Regeneração/genética
11.
J Proteome Res ; 11(3): 1666-75, 2012 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-22309186

RESUMO

Cyphomandra betacea (tamarillo) is a tree that produces edible, highly nutritional fruits. In tamarillo, somatic embryogenesis (SE) is achieved through a two-step process starting with the formation of an embryogenic tissue on an auxin-rich medium and further development of embryos, following tissue transfer to an auxin-free medium. During the induction stage, both embryogenic (EC) and nonembryogenic calli (NEC) arise from the same explant (immature leaves or mature zygotic embryos) in the presence of either picloram or 2,4-dichlorophenoxyacetic acid. In an attempt to find somatic embryogenic-specific proteins, a comparative analysis of the proteome of tamarillo's EC and NEC was performed. Analysis of 2-DE gels revealed ca. 150 differentially expressed proteins, from which 22 have been identified by LC-MS/MS. Proteins exclusively or predominantly expressed in EC included metabolism-related proteins, such as enolases or treonine synthases, and also heat-shock and ribosomal proteins. Pathogenesis-related proteins were found mainly in NEC. A number of additional differentially expressed proteins involved in various functional categories were also identified. A quantitative real time PCR (qPCR) analysis revealed no significant differences at the mRNA level for 11 differentially expressed proteins, with exception of the pathogenesis-related proteins that were up-regulated in NEC. This seems to indicate that a posttranscriptional control might be responsible for the proteomic differences detected.


Assuntos
Ácidos Indolacéticos/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/metabolismo , Técnicas de Embriogênese Somática de Plantas/métodos , Proteoma/metabolismo , Solanum/metabolismo , Eletroforese em Gel Bidimensional , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Mapeamento de Peptídeos , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Mapas de Interação de Proteínas , Proteoma/genética , Proteoma/isolamento & purificação , Proteômica , Solanum/efeitos dos fármacos , Transcrição Genética
12.
J Med Microbiol ; 60(Pt 5): 612-618, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21321363

RESUMO

In the present work we report for what we believe to be the first time the antifungal activity and mechanism of action of the essential oils of Lavandula viridis from Portugal. The essential oils were isolated by hydrodistillation and analysed by GC and GC/MS. The MIC and the minimal lethal concentration (MLC) of the essential oil and its major compounds were determined against several pathogenic fungi. The influence of subinhibitory concentrations of the essential oil on the dimorphic transition in Candida albicans was also studied, as well as propidium iodide and FUN-1 staining of Candida albicans cells by flow cytometry following short treatments with the essential oil. The oils were characterized by a high content of oxygen-containing monoterpenes, with 1,8-cineole being the main constituent. Monoterpene hydrocarbons were present at lower concentrations. According to the determined MIC and MLC values, the dermatophytes and Cryptococcus neoformans were the most sensitive fungi (MIC and MLC values ranging from 0.32 to 0.64 µl ml⁻¹), followed by Candida species (at 0.64-2.5 µl ml⁻¹). For most of these strains, MICs were equivalent to MLCs, indicating a fungicidal effect of the essential oil. The oil was further shown to completely inhibit filamentation in Candida albicans at concentrations well below the respective MICs (as low as MIC/16). Flow cytometry results suggested a mechanism of action ultimately leading to cytoplasmic membrane disruption and cell death. Our results show that L. viridis essential oils may be useful in the clinical treatment of fungal diseases, particularly dermatophytosis and candidosis, although clinical trials are required to evaluate the practical relevance of our in vitro research.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Lavandula/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Óleos Vegetais/química , Óleos Vegetais/farmacologia , Antifúngicos/isolamento & purificação , Arthrodermataceae/efeitos dos fármacos , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Testes de Sensibilidade Microbiana , Micoses/tratamento farmacológico , Óleos Voláteis/isolamento & purificação , Fitoterapia , Óleos Vegetais/isolamento & purificação , Portugal
13.
J Ethnopharmacol ; 130(3): 593-8, 2010 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-20538054

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Several aromatic plants and their essential oils are known to possess antimicrobial and anti-inflammatory properties. Distichoselinum tenuifolium (Lag.) Garcia Martin & Silvestre, an Iberian endemism, is traditionally used in the treatment of contact dermatitis and skin infections. However, the cellular mechanisms through which this plant exerts their beneficial effects are not known. AIM OF THE STUDY: The aims of this study were to examine the chemical composition of the essential oil isolated from Distichoselinum tenuifolium, and to test the efficacy of the essential oil as an antifungal and anti-inflammatory potential. MATERIALS AND METHODS: The oils were investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) and the antifungal activity (minimal inhibitory concentrations: MIC and minimal lethal concentrations: MLC) were evaluated against yeasts, dermatophyte and Aspergillus strains. Assessment of cell viability was made by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the in vitro anti-inflammatory potential of Distichoselinum tenuifolium oil was evaluated by measuring nitric oxide (NO) production induced by LPS, in the absence or in the presence of the oil, in a mouse macrophage cell line. RESULTS: The oils are predominantly composed of monoterpene hydrocarbons, being myrcene the main compound (47.7-84.6%). The oils revealed significant antifungal activity against Cryptococcus neoformans and dermatophyte strains and significantly inhibited NO production stimulated by LPS in macrophages, without affecting cell viability at concentrations ranging from 0.64 microL/mL to 1.25 microL/mL. CONCLUSION: These findings add significant information to the pharmacological activity of Distichoselinum tenuifolium essential oils, specifically to its antifungal and anti-inflammatory properties, thus justifying and reinforcing the use of this plant on traditional medicine. Therefore, their beneficial effects and use in disease prevention, especially those related to fungal infections and inflammation, should be explored in more depth.


Assuntos
Anti-Inflamatórios/farmacologia , Antifúngicos/farmacologia , Apiaceae/química , Óleos Voláteis/farmacologia , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/toxicidade , Antifúngicos/isolamento & purificação , Antifúngicos/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fungos/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Inflamação/tratamento farmacológico , Inflamação/fisiopatologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Medicina Tradicional , Camundongos , Testes de Sensibilidade Microbiana , Óxido Nítrico/biossíntese , Óleos Voláteis/isolamento & purificação , Óleos Voláteis/toxicidade , Portugal
14.
N Biotechnol ; 27(6): 882-92, 2010 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-20219713

RESUMO

Arbutus unedo grows spontaneously around the Mediterranean basin. The species is tolerant to drought and has a strong regeneration capacity following fires making it interesting for Mediterranean forestation programs. Considering the sparse information about the potential of this fruit tree to be propagated in vitro, a project to clone selected trees based on their fruit production was initiated a few years ago. The role of several factors on A. unedo propagation was evaluated. The results showed that 8.9 µm kinetin gave the best results although not significantly different from those obtained with benzyladenine or zeatin. The inclusion of thidiazuron or 1-naphthaleneacetic acid promoted callus growth and had deleterious effects on the multiplication rate. The genotype of the donor plants is also a factor interfering with the multiplication. The results also indicated that the conditions used for multiplication influenced the behavior of shoots during the rooting phase.


Assuntos
Ericaceae , Genótipo , Reguladores de Crescimento de Plantas/farmacologia , Árvores , Adenina/análogos & derivados , Adenina/farmacologia , Ericaceae/efeitos dos fármacos , Ericaceae/genética , Ericaceae/fisiologia , Cinetina/farmacologia , Ácidos Naftalenoacéticos/farmacologia , Compostos de Fenilureia/farmacologia , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Regeneração/efeitos dos fármacos , Tiadiazóis/farmacologia , Árvores/efeitos dos fármacos , Árvores/genética , Árvores/metabolismo , Zeatina/farmacologia
15.
Protoplasma ; 242(1-4): 95-107, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20336358

RESUMO

The presence of an attached organ to somatic embryos of angiosperms connecting the embryo to the supporting tissue has been a subject of controversy. This study shows that 67% of the morphologically normal somatic embryos of Feijoa sellowiana possess this type of organ and that its formation was not affected by culture media composition. Histological and ultrastructural analysis indicated that the attached structures of somatic embryos displayed a great morphological diversity ranging from a few cells to massive and columnar structures. This contrast with the simple suspensors observed in zygotic embryos which were only formed by five cells. As well as the suspensor of zygotic embryos, somatic embryo attached structures undergo a process of degeneration in later stages of embryo development. Other characteristic shared by zygotic suspensors and somatic embryo attached structures was the presence of thick cell walls surrounding the cells. Elongated thin filaments were often associated with the structures attached to somatic embryos, whereas in other cases, tubular cells containing starch grains connected the embryo to the supporting tissue. These characteristics associated with the presence of plasmodesmata in the cells of the attached structures seem to indicate a role on embryo nutrition. However, cell proliferation in the attached structures resulting into new somatic embryos may also suggest a more complex relationship between the embryo and the structures connecting it to the supporting tissue.


Assuntos
Feijoa/anatomia & histologia , Feijoa/embriologia , Sementes/anatomia & histologia , Desenvolvimento Embrionário , Feijoa/citologia , Feijoa/ultraestrutura , Sementes/citologia , Sementes/ultraestrutura
16.
Chem Biodivers ; 6(8): 1283-92, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19697345

RESUMO

The chemical composition and antifungal activity of the essential oils of Lavandula pedunculata (Miller) Cav., harvested in North and Central Portugal, were investigated. The essential oils were isolated by hydrodistillation and analyzed by GC and GC/MS. The minimal-inhibitory concentration (MIC) and the minimal-lethal concentration (MLC) of the essential oils and of their major constituents were used to evaluate the antifungal activity against different strains of fungi involved in candidosis, dematophytosis, and aspergillosis. The oils were characterized by a high percentage of oxygenated monoterpenes, the main compounds being 1,8-cineole (2.4-55.5%), fenchone (1.3-59.7%), and camphor (3.6-48.0%). Statistical analysis differentiated the essential oils into two main types, one characterized by the predominance of fenchone and the other one by the predominance of 1,8-cineole. Within the 1,8-cineole chemotype, two subgroups were well-defined taking into account the percentages of camphor. A significant antifungal activity of the oils was found against dermatophyte strains. The essential oil with the highest content of camphor was the most active with MIC and MLC values ranging from 0.32-0.64 microl/ml.


Assuntos
Antifúngicos/farmacologia , Lavandula/química , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Antifúngicos/química , Arthrodermataceae/efeitos dos fármacos , Cromatografia Gasosa , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Vegetais/química
17.
J Ethnopharmacol ; 119(1): 129-34, 2008 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-18606215

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Essential oils are known to possess antimicrobial activity against a wide spectrum of bacteria and fungi. Daucus carota L. is used since olden times in traditional medicine, due to recognized therapeutic properties, namely the antimicrobial activity of their essential oils. AIM OF THE STUDY: In the present study the composition and the antifungal activity of the oils of Daucus carota L. subsp. halophilus (Brot.) A. Pujadas (Apiaceae), an endemic plant from Portugal, were evaluated. Moreover, their cytotoxicity in mouse skin dendritic cells at concentration showing significant antifungal activity was also evaluated. MATERIAL AND METHODS: The oils were investigated by GC and GC-MS and the antifungal activity (MIC and MLC) were evaluated against yeasts, dermatophyte and Aspergillus strains. Assessment of cell viability was made by the MTT assay. RESULTS: The results showed large variations in the compositions during ontogenesis, particularly in the amounts of elemicin that increased significantly in the ripe umbels (5.9% vs. 31.0%). The results also demonstrated that the oil with high amounts of elemicin, which have stronger antifungal activity, showed no cytotoxic effect, at concentrations ranging from 0.16 to 0.64 microl/ml, for as long as 24h. CONCLUSION: It is possible to find appropriate doses of Daucus carota oil showing both antifungal activity and very low detrimental effect on mammalian cells.


Assuntos
Antifúngicos/administração & dosagem , Daucus carota/química , Óleos Voláteis/administração & dosagem , Animais , Antifúngicos/isolamento & purificação , Antifúngicos/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Gasosa , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Relação Dose-Resposta a Droga , Cromatografia Gasosa-Espectrometria de Massas , Medicina Tradicional , Camundongos , Testes de Sensibilidade Microbiana , Óleos Voláteis/isolamento & purificação , Óleos Voláteis/toxicidade , Portugal , Testes de Toxicidade
18.
Bull Environ Contam Toxicol ; 78(6): 421-6, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17492386

RESUMO

Tests aiming to determine the toxic properties of compounds discharged into aquatic systems have relied more on fish or invertebrates than on primary producers and among a number of producers; algae are the most popular test organisms. Macrophytes are important ecological elements in freshwaters and are therefore potentially key organisms for use in toxicity testing of compounds suspected of acting in primary producers. The most common macrophyte used in toxicity testing is Lemna sp., but as a floating plant, it has the limitation of being exposed to toxic compounds only through its lower leaf surface, including roots and rhizoids. Therefore, it is questionable whether tests with Lemna may accurately predict potential effects on submersed and exposed plant species, which have different routes of exposure and morphology. Few other submersed macrophytes have been tested, notably Myriophyllum. In the Iberian peninsula M. spicatum is the most common species within its genus and has been presented as a good bioaccumulator of heavy metals (Wang et al. 1996) and as being sensitive to several toxicants (e.g. Hanson et al. 2003). The aim of this study was to assess the potential of M. spicatum as a testing organism in laboratory assays, by obtaining axenic cultures of this plant and exposing them to several reference compounds to determine the sensitive endpoints.


Assuntos
Magnoliopsida , Poluentes Químicos da Água/toxicidade
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