Mesoporous silica nanoparticles incorporated with zinc oxide as a novel antifungal agent against toxigenic fungi strains.

Developing environmentally friendly alternative strategies to reduce the damage caused by fungi in agriculture has been widely investigated. In this study, we evaluated using mesoporous silica nanoparticles (MSNs) incorporated with zinc oxide (MSNs-ZnO) as a potential antifungal agent against Fusarium graminearum and Aspergillus flavus strains, as well as their antimycotoxin properties. The MSNs that synthesized and characterized could release abundant ZnO in the first 24 h. Subsequently, the ZnO release became slower, providing greater durability of the antifungal effect. Significant (P < 0.001) growth reductions in F. graminearum (81%) and A. flavus (65%) compared to the control were obtained at a high concentration of the MSNs-ZnO (1.0 mg mL-1). Moreover, the MSNs-ZnO treatment at a high concentration (1.0 mg mL-1) caused morphology alteration in both fungi, showing ruptures and deformations in the fungal hyphae, affecting their growth and toxin production. A significant reduction (P < 0.001) in the productions of deoxynivalenol (89%) and aflatoxin B1 (58%) by F. graminearum and A. flavus were also observed. These findings imply that using MSNs as the carriers of zinc compounds, such as ZnO, could be investigated as a safe alternative for effectively controlling toxigenic fungi in agriculture.

Gold nanoparticles alter parameters of oxidative stress and energy metabolism in organs of adult rats.

This study evaluated the parameters of oxidative stress and energy metabolism after the acute and long-term administration of gold nanoparticles (GNPs, 10 and 30 nm in diameter) in different organs of rats. Adult male Wistar rats received a single intraperitoneal injection or repeated injections (once daily for 28 days) of saline solution, GNPs-10 or GNPs-30. Twenty-four hours after the last administration, the animals were killed, and the liver, kidney, and heart were isolated for biochemical analysis. We demonstrated that acute administration of GNPs-30 increased the TBARS levels, and that GNPs-10 increased the carbonyl protein levels. The long-term administration of GNPs-10 increased the TBARS levels, and the carbonyl protein levels were increased by GNPs-30. Acute administration of GNPs-10 and GNPs-30 increased SOD activity. Long-term administration of GNPs-30 increased SOD activity. Acute administration of GNPs-10 decreased the activity of CAT, whereas long-term administration of GNP-10 and GNP-30 altered CAT activity randomly. Our results also demonstrated that acute GNPs-30 administration decreased energy metabolism, especially in the liver and heart. Long-term GNPs-10 administration increased energy metabolism in the liver and decreased energy metabolism in the kidney and heart, whereas long-term GNPs-30 administration increased energy metabolism in the heart. The results of our study are consistent with other studies conducted in our research group and reinforce the fact that GNPs can lead to oxidative damage, which is responsible for DNA damage and alterations in energy metabolism.

Incidence of toxigenic fungi and zearalenone in rice grains from Brazil.

Rice (Oryza sativa L.) is one of the most important food crops worldwide. In Brazil, the southern region is the area with the highest production of rice in the country and also has a high average daily intake of rice by the population. The mycoflora, mainly toxigenic Aspergillus and Fusarium species, the presence of AFB1, DON and ZEA in rice grains, as well as daily intake estimates for the Southern Brazilian population were evaluated. The rice grain samples were collected during the 2017 crop from different harvest periods. According to the mycological tests, the samples presented a high count of fungal colonies in the pre and post-harvest, where the incidence of the F. graminearum species complex (52%) was significantly predominant. This group can be responsible for ZEA production, as found in this study in parboiled rice, mainly because most of the isolated strains were producers of high ZEA levels in the pre-harvest (77%) and post-harvest after natural (79%) and artificial (75%) drying of the rice. Only ZEA showed significant results in the rice grain analyzed (60%) at levels of 90.56 to 126.31 µg/kg, where 36% of the samples were significantly higher than the current maximum limit stipulated in Brazilian regulations and by the European Commission. Despite this, the dietary exposure of ZEA estimated for the southern Brazilian population was below the provisional maximum tolerable daily intake level of 0.5 µg/kg body weight/day set at international regulations.

Inflammatory cytokines content in Achilles tendinopathy after phonophoresis treatment combined with gold nanoparticles and diclophenac diethylammonium in rats.

Tendinitis is a painful condition that occurs in tendons in response to repetitive use or direct trauma. The therapeutic approaches commonly employed to modulate inflammation have not achieved complete success in chronic cases of tendinitis. In this scenario, considering the anti-inflammatory properties of pulsed therapeutic ultrasound and gold nanoparticles (GNPs), this study assesses the possible therapeutic effects of phonophoresis in association with diclophenac diethylammonium and GNPs by measuring the inflammatory parameters interleukin 1ß and tumor necrosis factor alpha in acute tendinous injury. Wistar rats were randomly divided into three groups and were treated with phonophoresis and diclophenac diethylammonium, GNP gel, and a combination thereof. A significant decrease in interleukin 1ß and tumor necrosis factor alpha occurred in tendons treated with phonophoresis+diclophenac+GNPs. The content of both cytokines were similar after combined treatment with phonophoresis+diclophenac+GNPs. Apart from the anti-inflammatory effect, GNPs transported and enhanced drug action when used with phonophoresis.

Acute and chronic administration of gold nanoparticles cause DNA damage in the cerebral cortex of adult rats.

The use of gold nanoparticles is increasing in medicine; however, their toxic effects remain to be elucidated. Studies show that gold nanoparticles can cross the blood-brain barrier, as well as accumulate in the brain. Therefore, this study was undertaken to better understand the effects of gold nanoparticles on rat brains. DNA damage parameters were evaluated in the cerebral cortex of adult rats submitted to acute and chronic administration of gold nanoparticles of two different diameters: 10 and 30nm. During acute administration, adult rats received a single intraperitoneal injection of either gold nanoparticles or saline solution. During chronic administration, adult rats received a daily single injection for 28 days of the same gold nanoparticles or saline solution. Twenty-four hours after either single (acute) or last injection (chronic), the rats were euthanized by decapitation, their brains removed, and the cerebral cortices isolated for evaluation of DNA damage parameters. Our study showed that acute administration of gold nanoparticles in adult rats presented higher levels of damage frequency and damage index in their DNA compared to the control group. It was also observed that gold nanoparticles of 30nm presented higher levels of damage frequency and damage index in the DNA compared to the 10nm ones. When comparing the effects of chronic administration of gold nanoparticles of 10 and 30nm, we observed that occurred significant different index and frequency damage, comparing with control group. However, there is no difference between the 10 and 30nm groups in the levels of DNA damage for both parameters of the Comet assay. Results suggest that gold nanoparticles for both sizes cause DNA damage for chronic as well as acute treatments, although a higher damage was observed for the chronic one.