Chemoecological Screening Reveals High Bioactivity in Diverse Culturable Portuguese Marine Cyanobacteria     

Pedro N. Le?o  Vitor Ramos  Patrício B. Gon?alves  Flávia Viana  Olga M. Lage  William H. Gerwick  Vitor M. Vasconcelos 《Marine drugs》2013,11(4):1316-1335

Marine cyanobacteria, notably those from tropical regions, are a rich source of bioactive secondary metabolites. Tropical marine cyanobacteria often grow to high densities in the environment, allowing direct isolation of many secondary metabolites from field-collected material. However, in temperate environments culturing is usually required to produce enough biomass for investigations of their chemical constituents. In this work, we cultured a selection of novel and diverse cyanobacteria isolated from the Portuguese coast, and tested their organic extracts in a series of ecologically-relevant bioassays. The majority of the extracts showed activity in at least one of the bioassays, all of which were run in very small scale. Phylogenetically related isolates exhibited different activity profiles, highlighting the value of microdiversity for bioprospection studies. Furthermore, LC-MS analyses of selected active extracts suggested the presence of previously unidentified secondary metabolites. Overall, the screening strategy employed here, in which previously untapped cyanobacterial diversity was combined with multiple bioassays, proved to be a successful strategy and allowed the selection of several strains for further investigations based on their bioactivity profiles.  相似文献   

Assessment of Chemical and Physico-Chemical Properties of Cyanobacterial Lipids for Biodiesel Production     

Patrícia C. M. Da Rós  Caroline S. P. Silva  Maria E. Silva-Stenico  Marli F. Fiore  Heizir F. De Castro 《Marine drugs》2013,11(7):2365-2381

Five non-toxin producing cyanobacterial isolates from the genera Synechococcus, Trichormus, Microcystis, Leptolyngbya and Chlorogloea were examined in terms of quantity and quality as lipid feedstock for biofuel production. Under the conditions used in this study, the biomass productivity ranged from 3.7 to 52.7 mg·L⁻¹·day⁻¹ in relation to dry biomass, while the lipid productivity varied between 0.8 and 14.2 mg·L⁻¹·day⁻¹. All cyanobacterial strains evaluated yielded lipids with similar fatty acid composition to those present in the seed oils successfully used for biodiesel synthesis. However, by combining biomass and lipid productivity parameters, the greatest potential was found for Synechococcus sp. PCC7942, M. aeruginosa NPCD-1 and Trichormus sp. CENA77. The chosen lipid samples were further characterized using Fourier Transform Infrared spectroscopy (FTIR), viscosity and thermogravimetry and used as lipid feedstock for biodiesel synthesis by heterogeneous catalysis.  相似文献   

Further Insights on the Carotenoid Profile of the Echinoderm Marthasterias glacialis L     

LR Mariutti  DM Pereira  AZ Mercadante  P Valentão  N Teixeira  PB Andrade 《Marine drugs》2012,10(7):1498-1510

In this study, the carotenoid profile of the echinoderm Marthasterias glacialis L. was established using HPLC-DAD-APCI-MS/MS equipped with a C(30) column. This approach rendered the identification of 20 compounds, eight of them reported for the first time in this marine organism. Differentiation of carotenoid isomers was also achieved.  相似文献   

Improving in vitro induction of autopolyploidy in grapevine seedless cultivars     

Iraci Sinski  Daniela Dal Bosco  Neiva Izabel Pierozzi  João Dimas Garcia Maia  Patrícia Silva Ritschel  Vera Quecini 《Euphytica》2014,196(2):299-311

The efficiency of in vitro polyploidization depends on several variables associated to the plant, the antimicrotubule agent and the interactions between them. In the present work, we have used response-surface methodology to determine the best operating conditions for plant recovery in polyploidization assays for shoot apices and somatic embryos of two seedless grape cultivars, employing colchicine and oryzalin. Explant type, tubulin-interfering compound and concentration were the critical factors determining plant recovery. Linear reduction in viable plant regeneration via organogenesis and somatic embryogenesis was obtained by increasing oryzalin concentrations and treatment time, whereas the effects of colchicine were better described by a quadratic design for both explants types. The conditions promoting higher rates of plant recovery were used in chromosome doubling experiments with oryzalin and colchicine for shoot apices and somatic embryos of ‘Crimson seedless’ and ‘BRS Clara’. The established protocols allowed the recovery of non-chimerical autotetraploid plants at rates higher than 30 % for both cultivars. Stomata size parameters statistically correlate to the ploidy level of the regenerants and were effective for preliminary polyploidy screening. Autotetraploid lines of seedless grapes were incorporated into the Vitis germplasm bank for further agronomical evaluations. To our knowledge, this is the first report of in vitro oryzalin induced polyploidization of grapevine and of the use of mathematical modeling to optimize chromosome doubling in plants.  相似文献   

Bio-oil from base-catalyzed depolymerization of organosolv lignin as an antifungal agent for wood     

Patrícia Soares Bilhalva Dos Santos  Xabier Erdocia  Darci Alberto Gatto  Jalel Labidi 《Wood Science and Technology》2016,50(3):599-615

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Carbon and nitrogen mineralization in soil of leguminous trees in a degraded pasture in northern Rio de Janeiro,Brazil     

Danielle A. D. Nunes  Emanuela F. Gama-Rodrigues  Patrícia A. B. Barreto  Antonio C. Gama-Rodrigues  Paulo H. M. Monroe 《林业研究》2016,27(1):91-99

Use of legume trees can improve soil quality in degraded pastures. The aim of this study was to characterize C and N mineralization kinetics and estimate the potentially mineralizable C and N in soil under Mimosa caesalpiniifolia Benth. and Acacia auriculiformis A. Cunn.ex Benth. secondary forest and pasture in red-yellow latosols in southeast Brazil. We conducted a laboratory aerobic incubation experiment using a completely randomized design of four replicates and four types of plant cover using a modified version of the Stanford and Smith technique(1972) to study C and N mineralization potential.Potentially mineralizable N(N_o) ranged from 135 to170 mg kg-~(1). The predominant form of mineral N for all types of plant cover was N-NO_3~-. M. caesalpiniifolia was the only species that had a positive influence on N mineralization. Neither of the legumes influenced C mineralization in pasture or secondary forest. The model of N mineralization corresponded to a sigmoidal curve while C mineralization corresponded to an exponential curve,revealing that the N and C mineralization processes were distinct. N mineralized by M. caesalpiniifolia(216 kg of N ha~(-1)) was adequate to meet the N requirement for a livestock-forest system.  相似文献   

Factors associated with infection by Neospora caninum in dogs in Brazil     

Sicupira PM  de Magalhães VC  Galvão Gda S  Pereira MJ  Gondim LF  Munhoz AD 《Veterinary parasitology》2012,185(2-4):305-308

From August 2006 to 2008, 411 dogs in northeastern Brazil were evaluated for seropositivity to Neospora caninum. The dogs were clinically examined, and their owners were interviewed about the conditions in which the animals were maintained in order to assess the factors associated with infection by this parasite. A serum sample was taken from each dog for serological examination in an indirect fluorescent antibody test for N. caninum. The Yates' Chi-square test or Fisher's exact test was used to select the variables for the multivariate logistic regression model. Seropositivity was detected in 9.26% of dogs. The seropositivity rates of dogs from different environments were 2.6% (4/156) in urban areas, 13.1% (28/214) in peri-urban areas, and 14.6% (6/41) in rural areas. Factors associated with seropositivity for N. caninum were the following: contact with other dogs, access to food outside the home and residing in the peri-urban or rural environments (p<0.05). Results of this study confirm that dogs in urban, rural and peri-urban areas of northeastern Brazil are exposed to N. caninum. Control measures to prevent infection of dogs in the studied region should be focused primarily on preventing access to potential sources of infection, which include environments with other dogs, bovines, and other small intermediate hosts, such as birds and rodents.  相似文献   

Structural organization of the glnBA region of the Azospirillum brasilense genome     

Patrícia Castellen  Roseli Wassem  Rose Adele Monteiro  Leonardo Magalhães Cruz  Maria Berenice R. Steffens  Leda S. Chubatsu  Emanuel Maltempi de Souza  Fabio de Oliveira Pedrosa 《European Journal of Soil Biology》2009,45(1):100-105

The Azospirillum brasilense genomic region containing the glnBA genes was previously cloned in a broad-host range plasmid named pAB441. Previous results from our laboratory have shown that A. brasilense spontaneous mutants resistant to ethylenediamine carrying this plasmid had no nitrogenase activity. The 19 kb insert of this plasmid was fully sequenced and no other gene potentially involved with nitrogen fixation was identified, nor any gene potentially involved in the regulation of nif genes expression. Apart from glnBA, this region contains several genes involved with different functions: assisting protein folding and degradation, DNA organization, electron transport and energy conversion and conserved hypothetical proteins of unknown function. Since previous data on the literature showed that mutation of clpX gene of A. brasilense resulted in higher nitrogenase activity, we hypothesize that higher expression of the clpX gene from the plasmid pAB441 may be involved with Nif^? phenotype of the A. brasilense mutant strains.  相似文献   

HPLC-DAD-MS/MS-ESI screening of phenolic compounds in Pieris brassicae L. Reared on Brassica rapa var. rapa L     

Ferreres F  Valentão P  Pereira JA  Bento A  Noites A  Seabra RM  Andrade PB 《Journal of agricultural and food chemistry》2008,56(3):844-853

The phenolic profiles of cabbage white butterfly ( Pieris brassicae L.; Lepidoptera: Pieridae) at different development stages (larvae, exuviae, and butterfly), its excrements, and its host plant Brassica rapa var. rapa L. were determined by high performance liquid chromatography- diode-array detector-mass spectrometry/mass spectrometry-electrospray ionization (HPLC-DAD-MS/MS-ESI). Twenty-five acylated and nonacylated flavonoid glycosides and ferulic and sinapic acids were identified in host plant, from which only 12 compounds were found in the excrements. In addition, the excrements showed the presence of sulfate flavonoids and other flavonoid glycosides that were not detected in the leaves. In the larvae kept without food for 12 h, only 3 compounds common to the plant material and 2 others, also present in the excrements, were characterized. The results indicate that deacylation, deglycosylation, and sulfating steps are involved in the metabolic process of P. brassicae and that its excrements may constitute a promising source of bioactive compounds, which could be used to take profit of this common pest of Brassica cultures.  相似文献   

Chemical characterization of Citrus sinensis grafted on C. limonia and the effect of some isolated compounds on the growth of Xylella fastidiosa     

Ribeiro AB  Abdelnur PV  Garcia CF  Belini A  Severino VG  da Silva MF  Fernandes JB  Vieira PC  de Carvalho SA  de Souza AA  Machado MA 《Journal of agricultural and food chemistry》2008,56(17):7815-7822

Citrus sinensis grafted on C. limonia produces a considerable number of compounds that are not common in both plants developed from germination of seeds. The chemical profile of scion and rootstock differ notably for absence in the form of flavonoids and coumarins containing C5 prenyl groups attached to the carbon atoms of aromatic and heterocyclic systems or to oxygen. Only linear pyranocoumarins xanthyletin and xanthoxyletin were found in scion. This observation indicates that the prenylated compounds once biosynthesized in the roots could have been translocated to other organs. Xylella fastidiosa colonizes the xylem of plants causing diseases on several economically important crops such as citrus variegated chlorosis (CVC). A number of flavonoids, coumarins, alkaloids, dihydrocinnamic acid derivative, anacardic acid, triterpenes, and limonoids were tested for in vitro activity on the growth of Xylella fastidiosa. Azadirachtin A was the most active. Hesperidin, which occurs in great amounts in cells of the mesophyll of the affected leaves with CVC, showed a moderate activity suggesting that it can act as a good barrier for small-size colonies from X. fastidiosa.  相似文献