Transcriptomic Analysis Reveals the Roles of Detoxification Systems in Response to Mercury in Chromera velia

Abstract

Heavy metal pollution is an increasing global concern. Among heavy metals, mercury (Hg) is especially dangerous because of its massive release into the environment and high toxicity, especially for aquatic organisms. The molecular response mechanisms of algae to Hg exposure are mostly unknown. Here, we combine physiological, biochemical, and transcriptomic analysis to provide, for the first time, a comprehensive view on the pathways activated in Chromera velia in response to toxic levels of Hg. Production of hydrogen peroxide and superoxide anion, two reactive oxygen species (ROS), showed opposite patterns in response to Hg2+ while reactive nitrogen species (RNS) levels did not change. A deep RNA sequencing analysis generated a total of 307,738,790 high-quality reads assembled in 122,874 transcripts, representing 89,853 unigenes successfully annotated in databases. Detailed analysis of the differently expressed genes corroborates the biochemical results observed in ROS production and suggests novel putative molecular mechanisms in the algal response to Hg2+. Moreover, we indicated that important transcription factor (TF) families associated with stress responses differentially expressed in C. velia cultures under Hg stress. Our study presents the first in-depth transcriptomic analysis of C. velia, focusing on the expression of genes involved in different detoxification defense systems in response to heavy metal stress.

Enhancement of the Antioxidant and Skin Permeation Properties of Betulin and Its Derivatives

“…Betulin is a pentacyclic triterpene. Pentacyclic triterpenoids (including pentacyclic triterpenes such as betulin) are of interest to researchers due to their anti-inflammatory, antimicrobial, antitumor, cytotoxic, and other activities [ 14 , 15 , 18 , 25 , 27 , 28 , 29 , 30 , 36 , 37 , 38 , 39 ], and their possible use as intermediates in the synthesis of new pharmacological substances.…”

“…However, there are no literature reports describing the penetration of vehicles containing these compounds through the skin. Betulin shows a broad spectrum of biological activity (including cytotoxic activity [ 19 ]) because its structure contains substituents and groups, which can be easily functionalized (such as the isopropenyl moiety, alkyl group, and hydroxyl groups) [ 14 , 15 , 16 , 26 , 27 , 28 , 29 , 30 ]. Therefore, it seemed interesting to obtain new betulin derivatives, especially ketones—compound 8 ( Figure 1 ).…”

Cell death induced by mycotoxin fumonisin B1 is accompanied by oxidative stress and transcriptional modulation in Arabidopsis cell culture

“…ROS and RNS were quantified by fluorimetric analysis using specific fluorescent dyes, as in Sharaf et al (2019). In particular, 2,7-dichlorodihydrofluorescein diacetate (H 2 DCF-DA) is an intracellular marker that measures the level of oxidation inside a cell (Chen et al 2010a, b); dihydroethidium (DHE) is a specific marker for the superoxide anion (O 2 -) (Nazarewicz et al 2013); 4-Amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM-DA) is an intracellular specific marker for nitric oxide (NO) (Kojima et al 1999); Aminophenyl fluorescein (APF) is a marker for both peroxynitrite (ONOO − ) and hydroxyl radical (⋅OH), since the dye is unable to discriminate between the two molecules (Setsukinai et al 2003).…”

Insights into the Role of Oxidative Stress in Ovarian Cancer

“…Reactive oxygen species (ROS) are represented by free radicals and nonfree radical oxygen-containing molecules, including superoxide anions (O 2 · – ), hydrogen peroxides (H 2 O 2 ), singlet oxygens ( 1 O 2 ), and hydroxyl radicals (OH·) [ 12 , 13 ]. Reactive nitrogen species (RNS) include nitric oxide (NO·) and peroxynitrite anions (ONOO – ) [ 14 ] ( Figure 1 ). The generation of ROS and RNS is dependent on both enzymatic and nonenzymatic reactions.…”