Unraveling subcellular functional traits: Adaptive insights into chloroplast ultrastructure in nonmodel species Saulo Pireda, Maura Da Cunha American Journal of Botany, 2024 This essay discusses how the ultrastructural changes in chloroplasts, particularly the mechanisms of thylakoid membrane unstacking, help maintain the photosynthetic performance of photosystem II (PSII) under stress conditions. This phenomenon may facilitate the repair of damaged PSII by providing access to the repair machinery. It is argued that this PSII repair mechanism accelerates PSII recovery, optimizing photosynthetic processes in stressed plants. Although some studies demonstrate the relationship between thylakoid membrane unstacking in stress conditions, these studies were developed with model species under controlled conditions. Thus, this essay serves as a validation tool for these previous studies, because it demonstrates that the relationships between ultrastructural changes in chloroplasts and the functioning of PSII are essential acclimative strategies for nonmodel plants to survive the constant edaphoclimatic changes of natural environments. Understanding these subcellular dynamics can significantly inform biologists about the plastic potential of plants, especially in heterogeneous environments. An integrated approach in future studies is necessary, highlighting the importance of exploring plant functional traits at multiple scales, because subcellular characteristics have great potential to understand plant acclimatization.
Acute toxicity of titanium dioxide microparticles in Artemia sp. nauplii instar I and II Sergimar Kennedy de Paiva Pinheiro, Ana Kamila Medeiros Lima, Thaiz Batista Azevedo Rangel Miguel, Saulo Pireda, Pierre Basílio Almeida Fechine, et al. Microscopy Research and Technique, 2023 In this study, the toxicity effects of titanium dioxide (MTiO2) microparticles on Artemia sp. nauplii instar I and II between 24 and 48 h was evaluated. The MTiO2 were characterized using different microscopy techniques. MTiO2 rutile was used in toxicity tests at concentration of 12.5, 25, 50, and 100 ppm. No toxicity was observed in Artemia sp. nauplii instar I at the time of 24 and 48 h. However, Artemia sp. nauplii instar II toxicity was observed within 48 h of exposure. MTiO2 at concentrations of 25, 50 and 100 ppm was lethal for Artemia sp. with a significant difference (p ≤ .05) in relation to the control artificial sea water with LC50 value at 50 ppm. Analysis of optical and scanning electron microscopy revealed tissue damage and morphological changes in Artemia sp. nauplii instar II. By using confocal laser scanning microscopy, cell damage was observed due to the toxicity of MTiO2 at a concentration of 20, 50, and 100 ppm. The high mortality rate is related to the filtration of MTiO2 by Artemia sp. nauplii instar II due to the complete development of the digestive tract.
Programmed cell death in soybean seed coats Gustavo Lemos Rocha, Saulo Pireda, Jucélia da Silva Araújo, Antônia Elenir Amâncio Oliveira, Olga Lima Tavares Machado, et al. Plant Science, 2019