S-nitrosothiols Regulate Nitric Oxide Production And Storage In Plants Through The Nitrogen Assimilation Pathway.

Nitrogen assimilation plays a vital role in plant metabolism. Assimilation of nitrate, the primary source of nitrogen in soil, is linked to the generation of the redox signal nitric oxide (NO). An important mechanism by which NO regulates plant development and stress responses is through S-nitrosylation, that is, covalent attachment of NO to cysteine residues to form S-nitrosothiols (SNO). Despite the importance of nitrogen assimilation and NO signalling, it remains largely unknown how these pathways are interconnected. Here we show that SNO signalling suppresses both nitrate uptake and reduction by transporters and reductases, respectively, to fine tune nitrate homeostasis. Moreover, NO derived from nitrate assimilation suppresses the redox enzyme S-nitrosoglutathione Reductase 1 (GSNOR1) by S-nitrosylation, preventing scavenging of S-nitrosoglutathione, a major cellular bio-reservoir of NO. Hence, our data demonstrates that (S)NO controls its own generation and scavenging by modulating nitrate assimilation and GSNOR1 activity.

New Loci Of Lychnophora Ericoides And Transferability To Lychnophora Pinaster, Endangered Medicinal Species From Brazil.

Lychnophora ericoides and Lychnophora pinaster are species used in popular medicine as analgesic or anti-inflammatory agents to treat contusions, rheumatism, and insect bites. In this study, 21 simple sequence repeat loci of L. ericoides were developed and transferred to L. pinaster. Three populations of L. ericoides and 2 populations of L. pinaster were evaluated; they were collected in the State of Minas Gerais. Population parameters were estimated, and the mean values of observed and expected heterozygosity were 0.297 and 0.408 (L. ericoides) and 0.228 and 0.310 (L. pinaster), respectively. Greater genetic variability was observed within populations than between populations of L. ericoides (62 and 37%) and L. pinaster (97 and 2.8%). These results provide information for genetic conservation and taxonomic studies of these endangered species.

Contrasting Effects Of Land Use Intensity And Exotic Host Plants On The Specialization Of Interactions In Plant-herbivore Networks.

Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic plant species because they are neither capable of consuming alternative plant species of the native flora nor exotic plant species. Therefore, higher levels of land use intensity might reduce the proportion of highly specialized herbivores, which ultimately would lead to changes in the specialization of interactions in plant-herbivore networks. This study investigates the community-wide effects of land use intensity on the degree of specialization of 72 plant-herbivore networks, including effects mediated by the increase in the proportion of exotic plant species. Contrary to our expectation, the net effect of land use intensity on network specialization was positive. However, this positive effect of land use intensity was partially canceled by an opposite effect of the proportion of exotic plant species on network specialization. When we analyzed networks composed exclusively of endophagous herbivores separately from those composed exclusively of exophagous herbivores, we found that only endophages showed a consistent change in network specialization at higher land use levels. Altogether, these results indicate that land use intensity is an important ecological driver of network specialization, by way of reducing the local host range of herbivore guilds with highly specialized feeding habits. However, because the effect of land use intensity is offset by an opposite effect owing to the proportion of exotic host species, the net effect of land use in a given herbivore assemblage will likely depend on the extent of the replacement of native host species with exotic ones.

Authenticity study of Phyllanthus species by NMR and FT-IR Techniques coupled with chemometric methods

The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as quebra-pedras in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, ¹H HR-MAS NMR and ¹H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques.

Tissue culture of Cecropia glaziovii Sneth (urticaceae): vegetative micropropagation and plant regeneration from callus

Cecropia glaziovii is a tree with used in Brazilian popular medicine. Methods allowing the clonal propagation of this species are of great interest for superior genotype multiplication and perpetuation. For this reason, we examined the effect of different culture media and different types of explants on adventitious shoot regeneration from callus and buds of C. glaziovii. Leaves, petioles and stipules obtained from aseptically grown seedlings or from pre-sterilized plants were used to initiate cultures. Adventitious shoot regeneration was achieved when apical and axillary buds were inoculated on gelled Murashige & Skoog (MS) medium supplemented with 6-benzylaminopurine alone (BAP) (1.0, 5.0 or 10.0 mg L-1) or combined with -naphthalene acetic acid (NAA) (1.0 or 2.0 mg L-1), after 40 days of culture. Best callus production was obtained after 30 days of petioles' culture on gelled MS medium with 2,4 dichlorophenoxyacetic acid (2,4-D) (5.0 mg L-1) combined with BAP (1.0 mg L-1). Successful shoot regeneration from callus was achieved when MS medium supplemented with zeatin (ZEA) (0.1 mg L-1) alone or combined with 2,4-D (1.0 or 5.0 mg L-1) was inoculated with friable callus obtained from petioles. All shoots were rooted by inoculation on MS medium supplemented with indole-3-acetic acid (IAA) (1.0 mg L-1). Rooted plants transferred to potting soil were successfully established. All in vitro regenerated plantlets showed to be normal, without morphological variations, being also identical to the source plant. Our study has shown that C. glaziovii can be propagated by tissue culture methods, allowing large scale multiplication of superior plants for pharmacological purposes.

Rootstocks induce contrasting photosynthetic responses of orange plants to low night temperature without affecting the antioxidant metabolism

Low temperatures negatively impact the metabolism of orange trees, and the extent of damage can be influenced by the rootstock. We evaluated the effects of low nocturnal temperatures on Valencia orange scions grafted on Rangpur lime or Swingle citrumelo rootstocks. We exposed six-month-old plants to night temperatures of 20ºC and 8ºC under controlled conditions. After decreasing the temperature to 8ºC, there were decreases in leaf CO2 assimilation, stomatal conductance, mesophyll conductance and CO2 concentration in the chloroplasts, in plant hydraulic conductivity and in the maximum electron transport rate driven ribulose-1,5-bisphosphate (RuBP) regeneration in plants grafted on both rootstocks. However, the effects of low night temperature were more severe in plants grafted on Rangpur rootstock, which also presented reduction in the maximum rate of RuBP carboxylation and in the maximum quantum efficiency of the PSII. In general, irreversible damage due to night chilling was found in the photosynthetic apparatus of plants grafted on Rangpur lime. Low night temperatures induced similar changes in the antioxidant metabolism, preventing oxidative damage in citrus leaves on both rootstocks. As photosynthesis is linked to plant growth, our findings indicate that the rootstock may improve the performance of citrus trees in environments with low night temperatures, with Swingle rootstock improving the photosynthetic acclimation in leaves of orange plants.

Effect of silicate fertilization on soil and on palisade grass plants under grazing intensities

Application of calcium silicate (SiCa) as soil acidity corrective was evaluated in a Rhodic Hapludox soil with palisade grass conducted under pasture rotation system with different grazing intensities. Experimental design was complete randomized blocks with four grazing intensities - grazing intensities were imposed by forage supply (50, 100, 150 and 200 kg t-1 of DM per LW) - in experimental plots with four replicates and, in the subplots, with seven doses of calcium silicate combined with lime: 0+0, 2+0, 4+0, 6+0, 2+4, 4+2 and 0+6 t ha-1, respectively. In the soil, it was evaluated the effect of four levels of calcium silicate (0, 2, 4 and 6 t ha-1) at 45, 90, and 365 days at three depths (0-10, 10-20 and 20-40 cm) and at 365 days, it was included one level of lime (6 t ha-1). For determination of leaf chemical composition and silicate content in the soil, four levels of calcium silicate (0, 2, 4 and 6 t ha-1) were evaluated at 45 and 365 days and at 45 days only for leaf silicate, whereas for dry matter production, all corrective treatments applied were evaluated in evaluation seasons. Application of calcium silicate was positive for soil chemical traits related to acidity correction (pH(CaCl2), Ca, Mg, K, H+Al and V), but the limestone promoted better results at 365 days. Leaf mineral contents were not influenced by application of calcium silicate, but there was an increase on silicate contents in leaves and in the soil. Dry matter yield and chemical composition of palisade grass improved with the application of correctives.

Anatomia foliar de Eugenia florida DC. (Myrtaceae)

Foi feito o estudo anatômico da folha de Eugenia florida DC., espécie arbórea da família Myrtaceae, coletada no Campus da Fundação Oswaldo Cruz, Rio de Janeiro, RJ. A espécie apresenta importantes propriedades farmacológicas, incluindo-se atividade antiviral. O presente estudo teve como objetivo fornecer dados, revelados através da microscopia óptica e da microscopia eletrônica de varredura, que possam contribuir para o conhecimento da espécie e, conseqüentemente, para a segurança em sua identificação. Anatomicamente, a folha é hipostomática, com organização dorsiventral do mesofilo. Apresenta tricomas simples apenas sobre a nervura mediana da face adaxial. As células epidérmicas apresentam contorno sinuoso em vista frontal e cutícula estriada. O parênquima paliçádico destaca-se pela grande quantidade de cristais prismáticos de oxalato de cálcio. Em posição subepidérmica ocorrem cavidades secretoras de óleos essenciais, pouco numerosas, nas duas faces da lâmina foliar. As células epidérmicas situadas sobre as estruturas secretoras constituem característica de valor diagnóstico e são reconhecíveis pela célula de topo, que é reniforme, circundada pelas adjacentes, que apresentam disposição radiada. A comparação entre folhas de sol e de sombra revela que, nas primeiras, as estruturas secretoras são completamente diferenciadas, ao contrário das folhas de sombra, além de apresentarem maior concentração de compostos ergásticos.

Morfo-anatomia foliar de Myrcia multiflora (Lam.) DC. - Myrtaceae

Folhas de Myrcia multiflora (Lam.) DC. são usadas na medicina popular como hipoglicemiantes. O objetivo deste trabalho foi caracterizar morfológica e anatomicamente as folhas desta planta, de modo que os dados obtidos possam ser utilizados como referência em exames de controle de qualidade de amostras de fármacos, com vistas a verificar a autenticidade. Folhas inteiras foram diafanizadas e coradas para o estudo da nervação. Secções transversais do pecíolo e transversais e paradérmicas da lâmina foliar foram analisadas em microscópio óptico (MO) e a superfície do limbo foi observada, também, em microscopia eletrônica de varredura (MEV). Foram aplicados testes histoquímicos em material fresco, para identificação e localização de glicídios, amido, taninos, lignina, cristais e sílica. Morfologicamente, a folha é simples, oval-elíptica, com margem inteira, base aguda, ápice acuminado e textura cartácea. A venação é do tipo camptódromo-broquidódromo. Anatomicamente, a folha é hipostomática, com mesofilo compacto e dorsiventral, com três estratos de parênquima paliçádico. A epiderme é uniestratificada, silicificada em algumas regiões e as células exibem paredes anticlinais retas. Em posição subepidérmica ocorrem numerosas cavidades secretoras de óleos essenciais. Os feixes vasculares são colaterais e acompanhados por séries cristalíferas. Os dados obtidos são comparados com os de outras espécies de Myrtaceae e conclui-se que as características morfológicas e anatômicas de M. multiflora contribuem para a diagnose.

Constituents and antiproliferative activity of extracts from leaves of Croton macrobothrys

Croton macrobothrys Baill, Euphorbiaceae, is a tree from the Atlantic Forest in Southern Brazil, used in traditional medicine and popularly known as "dragon's blood" and "pau-sangue". Leaf n-hexane, dichloromethane and methanol extracts were analyzed by GC/MS and evaluated for their in vitro antiproliferative activity on cell lines 786-0 (kidney), HT-29 (colon), K562 (leukemia), NCI-ADR/RES (drug resistant ovary), NCI-H460 (lung), MCF-7 (mammary), PC-3 (prostate), OVCAR-3 (ovary), U251 (glioma) and UACC-62 (melanoma). The dicloromethane extract exhibited activity against all cell lines at the concentration 25 µg/mL, in particular on cell lines NCI-H460 (GI50 0.33 μg/mL) and K5662 (GI50 0.91 μg/mL). Relevant constituents in dichloromethane extract are the alkaloids corydine and salutaridine, as well as the diterpenes geranylgeraniol and crotonin-derived clerodanes.

Anti-oxidative and anti-ulcerogenic activity of Ipomoea imperati

Ipomoea imperati (Vahl) Griseb., Convolvulaceae, is used in traditional medicine for the treatment of inflammation, swelling and wounds, as well as to treat pains and stomach problems. This work evaluates the anti-oxidative activity by ESR (Electron Spin Resonance spectroscopy) and the preventive and curative actions of I. imperati in gastric ulcer animal model. Ipomoea imperati (200 mg/kg, p.o.) prevented the formation of gastric lesions in 78% (p<0.05) when compared with the negative control tween 80. Lanzoprazole, prevented in 85% the gastric lesions formation induced by ethanol (p<0.05). Therefore, the oral administration of I. imperati one hour before the ulcerogenic agent prevented the ulcer formation, conserving the citoprotection characteristics of the gastric mucosa and assuring the integrity of gastric glands and gastric fossets. The healing activity of I. imperati (200 mg/kg, p.o.) evaluated in chronic ulcer experiments induced by the acetic acid, was 72% (p<0.05). The positive control, ranitidine, healed 78% of the gastric lesions (p<0.05). The histological analysis confirmed the recovery of the mucosal layer and the muscle mucosal layer harmed by the acetic acid. Experiments in vitro with DPPH (2.2-diphenyl-1-picrylhydrazyl) of anti-oxidative activity demonstrated that I. imperati presents an IC50 of 0.73±0.01 mg/mL.

Multivariate analysis of the effects of soil parameters and environmental factors on the flavonoid content of leaves of Passiflora incarnata L., Passifloraceae

The aim of the present study was to evaluate the effect of soil characteristics (pH, macro- and micro-nutrients), environmental factors (temperature, humidity, period of the year and time of day of collection) and meteorological conditions (rain, sun, cloud and cloud/rain) on the flavonoid content of leaves of Passiflora incarnata L., Passifloraceae. The total flavonoid contents of leaf samples harvested from plants cultivated or collected under different conditions were quantified by high-performance liquid chromatography with ultraviolet detection (HPLC-UV/PAD). Chemometric treatment of the data by principal component (PCA) and hierarchic cluster analyses (HCA) showed that the samples did not present a specific classification in relation to the environmental and soil variables studied, and that the environmental variables were not significant in describing the data set. However, the levels of the elements Fe, B and Cu present in the soil showed an inverse correlation with the total flavonoid contents of the leaves of P. incarnata.

Análise colorimétrica e espectroscópica do muco de caracóis terrestres Achatina sp alimentados com ração diferenciada

Foram estudados os efeitos da adição de plantas medicinais de princípios cicatrizantes (Centelha asiática, Papaína e Confrei) na ração controle de caracóis terrestres, para se avaliar a interferência destas plantas na composição do muco glicoprotéico. Foram utilizados 80 caracóis terrestres Achatina sp, baseados em um peso homogêneo (49 e 40 g e idade média de 10 e 19 meses para Achatina fulica e Achatina monochromatica, respectivamente). Os animais foram distribuídos aleatoriamente em oito grupos experimentais: controle Achatina fulica (FC) e Achatina monochromatica (MC), centelha asiática Achatina fulica (FCe) e Achatina monochromatica (MCe), papaína Achatina fulica (FPa) e Achatina monochromatica (MPa) e confrei Achatina fulica (FCo) e Achatina monochromatica (MCo). Água e ração foram fornecidos ad libitum. Ao final de 150 dias de tratamento, os animais foram submetidos à técnica de extração do muco glicoprotéico, por meio do estímulo manual da glândula podal, responsável pela secreção deste muco. Esta metodologia considerou o bem-estar dos animais, uma vez que os mesmos não foram sacrificados e retornaram ao seu sistema de criação. Os mucos foram analisados por meio de testes colorimétricos e espectroscópicos, que constataram alterações semelhantes, porém apresentaram variação significativa em sua composição glicoprotéica.

Physical analysis of compost from composting plants in Brazil

Nowadays the composting process has shown itself to be an alternative in the treatment of municipal solid wastes by composting plants. However, although more than 50% of the waste generated by the Brazilian population is composed of matter susceptible to organic composting, this process is, still today, insufficiently developed in Brazil, due to low compost quality and lack of investments in the sector. The objective of this work was to use physical analyses to evaluate the quality of the compost produced at 14 operative composting plants in the Sao Paulo State in Brazil. For this purpose, size distribution and total inert content tests were done. The results were analyzed by grouping the plants according to their productive processes: plants with a rotating drum, plants with shredders or mills, and plants without treatment after the sorting conveyor belt. Compost quality was analyzed considering the limits imposed by the Brazilian Legislation and the European standards for inert contents. The size distribution tests showed the influence of the machinery after the sorting conveyer on the granule sizes as well as the inert content, which contributes to the presence of materials that reduce the quality of the final product

Pimarane-type Diterpenes: Antimicrobial Activity against Oral Pathogens

Seven pimarane type-diterpenes re-isolated from Viguiera arenaria Baker and two semi-synthetic pimarane derivatives were evaluated in vitro against the following main microorganisms responsible for dental caries: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis and Lactobacillus casei. The compounds ent-pimara-8(14), 15-dien-19-oic acid (PA); ent-8(14), 15-pimaradien-3 beta-ol; ent-15-pimarene-8 beta, 19-diol; ent-8(14), 15-pimaradien-3 beta-acetoxy and the sodium salt derivative of PA were the most active compounds, displaying MIC values ranging from 2 to 8 mu g.mL(-1). Thus, this class of compounds seems promising as a class of new effective anticariogenic agents. Furthermore, our results also allow us to conclude that minor structural differences among these diterpenes significantly influence their antimicrobial activity, bringing new perspectives to the discovery of new natural compounds that could be employed in the development of oral care products.