Effects of copper oxide nanoparticles on germination of Sesbania virgata (FABACEAE) plants.

Nanotechnology is a field that, over the years, has been growing in several research areas, such as medicine, agriculture and cosmetics, among others. As a result, there is a continuous increase in the production, use and disposal of these materials in the environment. The behaviour and (bio) activity of these materials in the atmosphere, water and soil are not fully studied. Therefore, it is necessary to carry out an analysis of the risks of contamination, as well as the possible effects and impacts of nanoparticles (NPs) on the ecosystem. In an attempt to investigate these effects on plants, the present study aimed to investigate the impact of copper oxide nanoparticles (CuO NPs) on the seed germination process of Sesbania virgata. For this, the Sesbania virgata seeds were subjected to different concentration of CuO NPs (0, 100, 200, 300 and 400 mgL-1) and their germination and development were monitored by optical analysis (thermography and chlorophyll a fluorescence). The results show that the CuO NPs induced a reduction on the maximum emission of chlorophyll a, which was concentration-dependent. The data also showed that CuO NPs promoted an increase in the energy dissipated by non-photochemical pathways and the surface temperature of the seeds. Additionally, our findings revealed that CuO NPs caused a root growth inhibition. In summary, the present study demonstrates, for the first time, that CuO NPs can negatively affect the physiological status and development of the S. virgata plant, by altering the efficiency of the functioning of photosystem II in its initial developmental stage, depending on the concentration of CuO NPs.

Evaluation of Eosin-Methylene Blue as a Photosensitizer for Larval Control of Aedes aegypti by a Photodynamic Process.

Aedes aegypti (Ae. aegypti) is a competent vector for transmitting important viral diseases such as yellow fever, dengue, chikungunya, and Zika. Several strategies have been applied to avoid Ae. aegypti proliferation by using environmental management, biological, and chemical approaches. However, the development of new methods for effective control of the insect vector population is still needed. Photodynamic control is an alternative way to control the vector population by using a physical approach based on the larval phototoxicity of a photosensitizer. In this context, the present study evaluated the use of eosin-methylene blue (EMB) as a new photosensitizer for photodynamic control of Ae. aegypti larval populations. The photodynamic assays were performed submitting Ae. aegypti third-instar larvae to different EMB concentrations (0.0, 0.5, 1.0, 5.0, 10.0, 50.0, and 100.0 µg mL-1) in combination of three different light doses (24.3, 48.6, and 97.2 J cm-2) under either white-light radiation from RGB LEDs or sunlight. The results demonstrated that EMB presented a rapid internalization into the larvae and was phototoxic. The photodynamic action induced 100% of larval mortality after about 40 min of sunlight irradiation even using low EMB concentration (0.5 µg mL-1). The findings reveal EMB as an effective photoactive compound to control larval populations of Ae. aegypti by photodynamic process induced by either sunlight or white-light from RGB LEDs.

Copper II - polar amino acid complexes: toxicity to bacteria and larvae of Aedes aegypti.

Control strategies using insecticides are sometimes ineffective due to the resistance of the insect vectors.In this scenario new products must be proposed for the control of insect vectors.The complexes L-aspartate Cu (II) and L-glutamate-Cu (II) complexes were synthesized and characterized by elemental analysis, visible ultraviolet, infrared spectroscopy and potentiometric titration. The toxicity of these complexes was analyzed in Aedes aegypti (Diptera: Culicidae) larvae and Gram-negative and Gram-positive bacteria. The interaction between the ligands and the amino acid balance and the distribution of the species as a function of pH were discussed. The lethal concentration median (LC50) for Ae. aegypti larvae were: L-glutamic acid-Cu (II) - 53.401 mg L-1 and L-aspartate-Cu (II) - 108.647 mg L-1. The minimum inhibitory concentration (MIC) required for Staphylococcus aureus and Escherichia coli was: L-glutamate-Cu (II) 500-2000 mg L-1 and L-aspartate-Cu (II) 1000-2000 mg L-1. The concentrations demonstrated toxicity that evidence the potential of the complexes as bactericide and insecticide. Metal complexes formed by amino acids and transition metals are advantageous because of low environmental toxicity, biodegradability and low production cost.

A potent larvicidal agent against Aedes aegypti mosquito from cardanol.

Cardanol is a constituent of Cashew Nut Shell Liquid that presents larvicidal activity against Aedes aegypti. The isolation of cardanol is somewhat troublesome, however, in this work we describe an efficient and inexpensive method to obtain it as a pure material. The compound was used as starting material to make chemical transformation leading to saturated cardanol, epoxides and, halohydrins. These derivatives were tested for toxicity against Aedes aegypti larvae. The results showed that iodohydrins are very promising compounds for making commercial products to combat the vector mosquito larvae presenting a LC50 of 0.0023 ppm after 72 h of exposure.

A potent larvicidal agent against Aedes aegypti mosquito from cardanol

ABSTRACT Cardanol is a constituent of Cashew Nut Shell Liquid that presents larvicidal activity against Aedes aegypti. The isolation of cardanol is somewhat troublesome, however, in this work we describe an efficient and inexpensive method to obtain it as a pure material. The compound was used as starting material to make chemical transformation leading to saturated cardanol, epoxides and, halohydrins. These derivatives were tested for toxicity against Aedes aegypti larvae. The results showed that iodohydrins are very promising compounds for making commercial products to combat the vector mosquito larvae presenting a LC50 of 0.0023 ppm after 72 h of exposure.

Photoinactivation effect of eosin methylene blue and chlorophyllin sodium-copper against Staphylococcus aureus and Escherichia coli.

The use of eosin methylene blue according to Giemsa as photosensitizer is presented for the first time in this paper. The present study evaluated the potential application of chlorophyllin sodium copper salt (CuChlNa) and eosin methylene blue according to Giemsa (EMB) as antimicrobial photosensitizers (aPS) for photodynamic inactivation (PDI) of Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative) bacteria. The experiments were performed using S. aureus stain ATCC 25923 and E. coli ATCC 25922 in which five aPS concentrations (0.0, 1.0, 2.5, 5.0, 10.0, and 20.0 µM for S. aureus and 0.0, 5.0, 10.0, 20.0, 40.0, and 50.0 µM for E. coli) were prepared and added in 2 mL of a saline solution containing the bacterial inoculum. After aPS incubation, the samples were divided into two groups, one kept in the dark and another submitted to the illumination. Then, the bacterial inactivation was determined 18 h after the incubation at 37 °C by counting the colony-forming units (CFU). The results revealed that both EMB and CuChlNa can be used as aPS for the photoinactivation of S. aureus, while only EMB was able to photoinactivate E. coli. Nevertheless, a more complex experimental setup was needed for photoinactivation of E. coli. The data showed that EMB and CuChlNa presented similar photoinactivation effects on S. aureus, in which bacterial growth was completely inhibited at photosensitizer (PS) concentrations over 5 µM, when samples were previously incubated for 30 min and irradiated by a light dose of 30 J cm-2 as a result of an illumination of 1 h at 8.3 mW cm-2 by using a red light at 625 nm with a 1 cm beam diameter and output power of 6.5 mW. In the case of E. coli, bacterial growth was completely inhibited only when combining a PS incubation period of 120 min with concentrations over 20 µM.

Copper II - polar amino acid complexes: toxicity to bacteria and larvae of Aedes aegypti

ABSTRACT Control strategies using insecticides are sometimes ineffective due to the resistance of the insect vectors.In this scenario new products must be proposed for the control of insect vectors.The complexes L-aspartate Cu (II) and L-glutamate-Cu (II) complexes were synthesized and characterized by elemental analysis, visible ultraviolet, infrared spectroscopy and potentiometric titration. The toxicity of these complexes was analyzed in Aedes aegypti (Diptera: Culicidae) larvae and Gram-negative and Gram-positive bacteria. The interaction between the ligands and the amino acid balance and the distribution of the species as a function of pH were discussed. The lethal concentration median (LC50) for Ae. aegypti larvae were: L-glutamic acid-Cu (II) - 53.401 mg L-1 and L-aspartate-Cu (II) - 108.647 mg L-1. The minimum inhibitory concentration (MIC) required for Staphylococcus aureus and Escherichia coli was: L-glutamate-Cu (II) 500-2000 mg L-1 and L-aspartate-Cu (II) 1000-2000 mg L-1. The concentrations demonstrated toxicity that evidence the potential of the complexes as bactericide and insecticide. Metal complexes formed by amino acids and transition metals are advantageous because of low environmental toxicity, biodegradability and low production cost.

Influence of agronomic variables on the macronutrient and micronutrient contents and thermal behavior of mate tea leaves (Ilex paraguariensis).

The influence of agronomic variables (light intensity, age of leaves, and fertilization type) on the content of macronutrients and micronutrients (potassium, calcium, sodium, magnesium, manganese, iron, zinc, and copper) of tea leaves was assessed by acid digestion, followed by flame atomic absorption spectrometry (FAAS). The thermal behavior of mate tea leaves (Ilex paraguariensis) was also studied in this work. Samples of mate (Ilex paraguariensis) were collected in an experiment conducted under agronomic control at Erva-Mate Barão Commerce and Industry LTD (Brazil). The results showed that the mineral content in mate is affected by the agronomic variables investigated. In general, the content of mineral compounds analyzed is higher for younger leaves and for plants cultivated in shadow. Thermal analysis of samples indicated a similar behavior, with three typical steps of decomposition: loss of water, degradation of low-molecular weight compounds, and degradation of residual materials.

Phenylboronate-chitosan resins for adsorption of beta-amylase from soybean extracts.

Isolation and purification of bioproducts from crude extracts can be obtained by affinity methods based on reversible binding of a specific molecule to ligand immobilized in a porous matrix. In the present work, nicrospheres based on chitosan matrix, which incorporated aminophenylboronic acid as a derivative, were prepared and characterized, aimed at developing a beta-amylase adsorption process. Kinetic curves and adsorption isotheriru of the crude extracts as well as the breakthrough curves for a frontal chromatographic separation method of a commercial sample of beta-amylase from soybean are presented. These results were compared to similar data obtained with a comercial microspheres gel based-on agarose.