Nanoparticles can easily reach soil,water and foodstuffs. The zinc oxide nanoparticle (ZnONP), which is a type of nanoparticle with known antiviral/microbial properties used frequently in cosmetic UV protection products, can damage the cell membrane/wall complex in Saccharomyces cerevisiae after exposure. However, the capacity of hsp150, an o-mannosylated heat shock protein needed for the strength of the S. cerevisiae cell wall, to prevent ZnONP toxicity/genotoxicity has not been investigated before. In this study, HSP150 gene of S. cerevisiae cells was deleted and the effects on the toxicity caused by ZnONPs were investigated by MTT, cell wall/membrane damage analyses and zymolyase susceptibility test. In addition, the level of oxidative DNA damage was determined by 8-OHdG test in the HSP150 deficient cells (hsp150 Delta). IC50 values observed in hsp150 Delta cells were lower than the wild type cells. In addition, the lowest dose of ZnONPs (250 mu g/mL) was significant enough to damage the cellular integrity in hsp150 Delta cells and DNA damage levels observed in the hsp150 Delta cells exposed to the lowest dose of the nanoparticles were nearly 2.5 times higher than the wild type cells. Therefore, it can be concluded that the HSP150 gene is needed for the cellular protection against ZnONP toxicity and genotoxicity.

AimHigh temperatures during forest fires can cause significant damage to tropical dry forest areas and alter their ecological stability, particularly by affecting seed viability and seedling emergence. This study evaluates the seedling emergence response of 18 dry forest species to fire-simulated temperatures, aiming to assess their potential for restoration in fire-prone Colombian ecosystems.LocationThe seeds used in this study were obtained from three tropical dry forests in Colombia.MethodsA total of 9832 seeds from 18 dry forest species were collected directly from the soil seed bank in three tropical dry forests in Colombia. These seeds were then exposed to simulated forest fire temperatures (100 degrees C, 150 degrees C, and 200 degrees C) for 10 min. Seed viability was analyzed using the 2,3,5-triphenyl tetrazolium chloride reagent (tetrazolium test) and assessed using a generalized linear model. Seedling emergence and mean emergence time were evaluated using one-way analysis of variance (ANOVA) with temperature treatments as factors.ResultsThe study revealed that seedling emergence significantly decreased with higher heat shock temperatures. Notably, Hura crepitans and Parkinsonia aculeata tolerated temperatures up to 100 degrees C, while Caesalpinia pulcherrima and Enterolobium cyclocarpum showed increased emergence at that temperature. Based on their emergence responses, species were classified as stimulated, tolerant, sensitive, or vulnerable. Seed viability declined with rising temperatures, and the mean emergence time increased in species like Cordia alba, Crescentia cujete, and Lonchocarpus violaceus.ConclusionsThis study shows that heat shocks at 150 degrees C and 200 degrees C significantly reduced seed bank viability for most Colombian dry forest species. However, Caesalpinia pulcherrima and Enterolobium cyclocarpum were stimulated by 100 degrees C heat shocks, while Hura crepitans and Parkinsonia aculeata showed no adverse effects. Vulnerable species like Coccoloba acuminata and Pithecellobium dulce exhibited no viable seeds at higher temperatures, suggesting potential local extinctions. These results emphasize the need to focus on heat-tolerant species for restoration efforts in fire-prone ecosystems.