Phytotoxicity associated to microcystins: a review

Microcystins (MC) are the most studied toxins of cyanobacteria since they are widely distributed and account for several cases of human and animal poisoning, being potent inhibitors of the serine/threonine protein phosphatases 1 (PP1) and 2A (PP2A). The phosphatases PP1 and PP2A are also present in plants, which may also suffer adverse effects due to the inhibition of these enzymes. In aquatic plants, biomass reduction is usually observed after absorption of cyanotoxins, which can bioaccumulate in its tissues. In terrestrial plants, the effects caused by microcystins vary from inhibition to stimulation as the individuals develop from seedling to adult, and include reduction of protein phosphatases 1 and 2A, oxidative stress, decreased photosynthetic activity and even cell apoptosis, as well as bioaccumulation in plant tissues. Thus, the irrigation of crop plants by water contaminated with microcystins is not only an economic problem but becomes a public health issue because of the possibility of food contamination, and this route of exposure requires careful monitoring by the responsible authorities.

The use of grafting to improve the net photosynthesis of cucumber

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Isotope analysis (δ 13c) of pulpy whole apple juice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of the natural variation of 13C:12C ratio in leaves at Reserva Ducke Forest, central Amazonia

Investigation of carbon isotope fractionation by plants was carried out at two sub-areas located in Reserva Ducke, central Amazonia: open reserve (virgin forest with low density of plant species); and closed reserve (virgin forest with high density of plant species). Preliminary results (δ‰ 13C: 12C values, PDB) of leaf analysis at different plant heights indicate the following: Eschweilera matamata Hub. (Lecythidaceae), common name 'matamata', -31.55±0.61; Protium heptaplyllum March. (Burseraceae), common name 'breu branco', -32.34±1.39; Calophyllum brasiliense Camb. (Guttiferae), common name 'jacareúba', -30.72±0.23; Scleronema micrantthum Ducke. (Bombacaceae), common name 'cardeiro'. -28.81±0.68; and Carapa guianensis Aubl. (Meliaceae), common name 'andiroba', -31.07±0.51. It is possible that the plant species analysed belong to the C3 photosynthetic cycle. In general, the species in the open reserve show differences of the order of 1.66±0.34‰ (greater in 13C) as compared with the same species in the closed reserve. The old leaves show differences in the relative isotopic enrichment (δ) of the order of 1‰, being smaller in new leaves in both reserves. The probable occurrence of an isotopic gradient from the lower (2-5 m) to the upper part (15-20 m) of the plant, of the order of 1.3‰, smaller in 13C, in species from the dense forest was noted. However, only two plants from each species were analysed during a two-year period, data obtained to far are still preliminary, and results should, therefore, be revised. Moreover, according to the literature, the natural carbon isotope fractionation by plants shows metabolic, physiological and environmental dependence. © 1991.

Analysis of metabolic pools in broilers chicks

This paper shows the possibility of obtaining new parameters for the mathematical modelling of data on stable isotopes in biological systems and its application in obtaining data on metabolic pools of blood plasma, blood serum, liver and muscle of broilers. This theory states that the modelling of turnover used for studies of isotopic incorporation when the metabolism has a single metabolic pool is feasible by the technique of setting an exponential. However, when the metabolism has more than one metabolic pool, it is necessary to apply the linearization technique, linear regression adjustment and evaluation of the assumptions of regression to obtain the kinetic parameters such as half-life (T1/2) and isotope exchange rate (k). The application of this technique on carbon-13 data from 100 one-day-old chicks, with the change of diet composed of grains of the photosynthetic cycle of plants from C4 to C3, in broilers has enabled the discovery that the liver, blood plasma and blood serum have a single metabolic pool; however, the pectoral muscle has two metabolic pools. For the liver, blood plasma and blood serum, the half-life values were found by the exponential fit being T1/2 = 1.4 days with the rate of exchange of k = 0.502, T1/2 = 2.4 days with k = 0.293 and T1/2 = 2.0 days with k = 0.348, respectively. For the pectoral muscle, after linearization, the half-life values were found for T1/2(1) = 1.7 and T1/2(2) = 3 days, with exchange rates of k1 = 0.405 and k2 = 0.235, representing approximately 66 and 34 %, respectively.

Manutenção de dois sistemas radiculares em aspectos bioquímicos e fisiológicos durante o desenvolvimento de plantas e desempenho agronômico de Passiflora edulis Sims enxertadas

Pós-graduação em Agronomia (Horticultura) - FCA

Metabolismo, desenvolvimento e composição química de Varronia curassavica Jacq. em função da supressão da irrigação

Pós-graduação em Agronomia (Horticultura) - FCA

Retenção de clorofila em sementes de soja (Glycine max (L.) Merr.): estudos fisiológicos, bioquímicos e moleculares

Pós-graduação em Agronomia (Agricultura) - FCA

Avaliações fisiológicas de sorgo sacarino inoculado com Azospirillum brasilense em função da adubação nitrogenada e reguladores vegetais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Níveis de carboidratos e lipídios em dietas para juvenis de tambaqui (Colossoma macropomum): variáveis produtivas, fisiológicas e turnover isotópico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sensitivity of yellow passion fruit plants to ultraviolet-B radiation

The objective of this work was to evaluate the effects of UV-B radiation on the vegetative growth and on the gas exchange characteristics of passion fruit plants (Passiflora edulis) grown in greenhouse. The average unweighted UV-B radiation near the apex of the plants was 8 W m-2 for the UV-B treatment (high UV-B), and 0.8 W m-2 for the control plants (low UV-B). Plants were irradiated with UV-B for 7 hours per day, centered on solar noon, during 16 days. High UV-B radiation resulted in lower shoot dry matter accumulation per plant. The content of UV-B absorbing compounds and anthocyanins was increased in the plants exposed to high UV-B radiation, when compared with the control. UV-B radiation did not affect stomatal conductance or transpiration rate, but reduced photosynthesis and instantaneous water‑use efficiency, and increased intercellular CO2 concentration. The accumulation of UV-B-absorbing compounds and anthocyanins did not effectively shield plants from supplementary UV-B radiation, since the growth and photosynthetic processes were significantly reduced.

The chemical oxygen demand / total volatile acids ratio as an anaerobic treatability indicator for landfill leachates

In some operational circumstances a fast evaluation of landfill leachate anaerobic treatability is necessary, and neither Biochemical Methane Potential nor BOD/COD ratio are fast enough. Looking for a fast indicator, this work evaluated the anaerobic treatability of landfill leachate from São Carlos-SP (Brazil) in a pilot scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR). The experiment was conducted at ambient temperature in the landfill area. After the acclimation, at a second stage of operation, the AnSBBR presented efficiency above 70%, in terms of COD removal, utilizing landfill leachate without water dilution, with an inlet COD of about 11,000 mg.L-1, a TVA/COD ratio of approximately 0.6 and reaction time equal to 7 days. To evaluate the landfill leachate biodegradability variation over time, temporal profiles of concentration were performed in the AnSBBR. The landfill leachate anaerobic biodegradability was verified to have a direct and strong relationship to the TVA/COD ratio. For a TVA/CODTotal ratio lower than 0.20, the biodegradability was considered low, for ratios between 0.20 and 0.40 it was considered medium, and above 0.40 it was considered high.

Análise isotópica do gás carbônico de espumantes comercializados no Brasil

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Caracterização fisiológica, bioquímica e anatômica em genótipos de algodoeiro herbáceo (gossypium hirsutum l.var. latifolium hutch) em função da aplicação de cloreto de mepiquat

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Turnover do δ¹³C na substituição de dietas com ingredientes de diferentes ciclos fotossintéticos em ovos de codornas japonesas (Coturnix coturnix japonica)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)