Oxidative stress responses and cellular energy allocation changes in microalgae following exposure to widely used human antibiotics

The individual effect of four human antibiotics on the microalgae Raphidocelis subcapitata was investigated following a 120-h exposure. The effects were assessed by analyzing growth, and biochemical parameters related with: 1) antioxidant capacity and oxidative damage by measuring superoxide dismutase (SOD) activity and lipid peroxidation (LPO) levels; and 2) cellular energy allocation (CEA) by quantifying the content in energy reserves, which represents the energy available (Ea), and the electron transport system activity that represents a measure of oxygen and cellular energy consumption (Ec). Growth yield inhibitory concentrations of sulfamethoxazole (18-30%), clarithromycin (28.7%), ciprofloxacin (28%) and erythromycin (17-39%) were found to elicit a considerable increase in Ec, thereby causing a significant decrease in the CEA. The elevated Ec can be a result of the need to respond to oxidative stress occurring under those conditions given the significant increase in SOD activity at these levels. For sulfamethoxazole, erythromycin and ciprofloxacin, the antioxidant responses do not seem to be enough to cope with the reactive oxygen species and prevent oxidative damage, given the elevated LPO levels observed. A stimulatory effect on growth yield was observed (up to 16%) at ciprofloxacin lowest concentration, which highly correlated with the increase in CEA. Based on the no observed effect concentration (NOECs) and/or effective concentration (EC10) results, Ec, SOD and CEA were more sensitive than the classical endpoint of growth rate for all the tested antibiotics. By revealing the antibiotic stress effects in R. subcapitata at the cellular level, this study suggests CEA as a more reliable indicator of the organisms' physiological status.info:eu-repo/semantics/publishedVersio

Effects on biomarkers in stress ecology studies. Well, so what? What now?

The authors would like to thank Fundação para a Ciência e a Tecnologia (FCT) for the support through funding of MARE (UIDB/04292/2020 and UIDP/04292/2020), ARNET—Aquatic Research Network Associated Laboratory (LA/P/0069/2020), MARINE INVADERS (PTDC/BIA-CBI/31144/2017), BLUESHARKER (PTDC/BIA-CBI/29136/2017), and OPTOX (PTDC/CTA-AMB/30056/2017). B. Duarte and V. F. Fonseca were supported by researcher contracts (CEEC-IND/00511/2017 and 2021.00244.CEECIND, respectively).1. Biomarkers in Stress Ecology - From the Gene to Population Effects assessed at higher levels of biological organization (populations and communities) are the consequence of the sum of effects on individuals, which usually result from impacts at cellular and molecular levels. Given this rationale, these lower levels of biological organization are more responsive at an early stage, making them potential resources that can be used as early warning endpoints to address environmental stress. In this way, the information concerning effects at the molecular level of biological organization (e.g., transcripts, proteins, or metabolites) allows for an early assessment of future ecosystem problems, which may eventually enable a timely intervention before the impacts become visible and irreversible. However, despite providing an early warning and a better understanding of the toxicity mechanisms, enabling the protection of biological integrity, the most significant setback is that these endpoints may fail to foresee later impacts on the environment due to the ecosystem resilience or a weak link to the effects in the following level of biological organization, making these tools simply too conservative for stakeholders’ interests. Hence, an approach targeting lower levels of biological organization will greatly benefit from addressing potential effects at higher levels. This can be achieved by establishing a link in biological organization, where the effects assessed at the lower end of biological organization are linked with the high probability of causing an effect at the other end, inducing changes in populations and communities, and eventually altering ecosystems in the future.info:eu-repo/semantics/publishedVersio

Evaluation of multivariate biomarker indexes application in ecotoxicity tests with marine diatoms exposed to emerging contaminants

Worldwide anthropogenic activities result in the production and release of potentially damaging toxic pollutants into ecosystems, thereby jeopardizing their health and continuity. Research studies and biomonitoring programs attend to this emerging problematic by applying and developing statistically relevant indexes that integrate complex biomarker response data to provide a holistic approach, reflecting toxically induced alterations at the organism or population level. Ultimately, indexes allow simple result communications, enhancing policy makers understanding, and contributing to better resource and environmental managing policies. In this study three indexes, the integrated biomarker response index (IBR), the bioeffects assessment index (BAI) and principal components analysis (PCA), were evaluated for their sensitivity in revealing toxically induced stress patterns in cells of the diatom Phaeodactylum tricornutum under contaminant exposure. The set of biomarkers selected for index construction comprised the anti-oxidant enzymes APX, CAT and SOD, and the lipid peroxidation marker TBARS. Several significant correlations with the applied concentration gradients were noticed for all indexes, although IBR excelled for its reliability in delivering statistically significant dose-response patterns for four out of the five tested compounds.info:eu-repo/semantics/publishedVersio

Industry-friendly hydroethanolic extraction protocols for Grateloupia turuturu UV-shielding and antioxidant compounds

Grateloupia turuturu is an invasive macroalga on the Iberian coast, known to produce bioactive compounds with di erent cosmeceutical bioactivities, namelyUVshielding and antioxidants. The goal of this study was to optimize the extraction procedure of main bioactivities of this species with cosmetic potential, using Response Surface Methodology. Two Box–Behnken designs were used to evaluate the e ect of ethanol concentration (0–50%), liquid-solid ratio, time, pH, and temperature on yield, UV absorbance, and antioxidant activity. Both optimizations showed a similar trend: aqueous extracts have higher yields and extracts performed with ethanol as part of the solvent have higher activities concerning UV absorbance and antioxidant activity. For all the extracts an absorption peak between 320 and 340 nm was observed. This data now allows further studies by narrowing the extracts worthful of characterization. The development of industry-friendly extraction methods allows the valorization of this invasive species, contributing for the potential creation of natural and eco-friendly products by the cosmetic industry while contributing to the restoration of affected environments.info:eu-repo/semantics/publishedVersio

Evaluating the in vitro potential of natural extracts to protect lipids from oxidative damage

Lipid peroxidation is a chemical reaction known to have negative impacts on living organisms’ health and on consumer products’ quality and safety. Therefore, it has been the subject of extensive scientific research concerning the possibilities to reduce it, both in vivo and in nonliving organic matrices. It can be started by a variety of oxidants, by both ROS-dependent and -independent pathways, all of them reviewed in this document. Another feature of this reaction is the capacity of lipid peroxyl radicals to react with the non-oxidized lipids, propagating the reaction even in the absence of an external trigger. Due to these specificities of lipid peroxidation, regular antioxidant strategies—although being helpful in controlling oxidative triggers—are not tailored to tackle this challenge. Thus, more suited antioxidant compounds or technologies are required and sought after by researchers, either in the fields of medicine and physiology, or in product development and biotechnology. Despite the existence of several laboratory procedures associated with the study of lipid peroxidation, a methodology to perform bioprospecting of natural products to prevent lipid peroxidation (a Lipid Peroxidation Inhibitory Potential assay, LPIP) is not yet well established. In this review, a critical look into the possibility of testing the capacity of natural products to inhibit lipid peroxidation is presented. In vitro systems used to peroxidize a lipid sample are also reviewed on the basis of lipid substrate origin, and, for each of them, procedural insights, oxidation initiation strategies, and lipid peroxidation extent monitoring are discussed.info:eu-repo/semantics/publishedVersio

Asparagopsis armata exudate cocktail: the quest for the mechanisms of toxic action of an invasive seaweed on marine invertebrates

The seaweed Asparagopsis armata exhibits a strong invasive behavior, producing halogenated compounds with effective biological effects. This study addresses the biochemical responses to sublethal concentrations of A. armata exudate on the marine snail Gibbula umbilicalis whole body and the shrimp Palaemon elegans eyes and hepatopancreas. Antioxidant defenses superoxide dismutase (SOD) and glutathione-S-transferase (GST), oxidative damage endpoints lipid peroxidation (LPO) and DNA damage, the neuronal parameter acetylcholinesterase (AChE), and the fatty acid profile were evaluated. Results revealed different metabolic responses in both species. Despite previous studies indicating that the exudate affected G. umbilicalis’ survival and behavior, this does not seem to result from oxidative stress or neurotoxicity. For P. elegans, the inhibition of AChE and the decrease of antioxidant capacity is concomitant with the increase of LPO, suggesting neurotoxicity and oxidative stress as contributor mechanisms of toxicity for this species. Fatty acid profile changes were more pronounced for P. elegans with a general increase in polyunsaturated fatty acids (PUFAs) with the exudate exposure, which commonly means a defense mechanism protecting from membrane disruption. Nonetheless, the omega-3 PUFAs arachidonic acid (ARA) and docosapentaenoic acid (DPA) increased in both invertebrates, indicating a common regulation mechanism of inflammation and immunity responsesinfo:eu-repo/semantics/publishedVersio

A biorefinery approach to the biomass of the seaweed Undaria pinnatifida (Harvey Suringar, 1873): obtaining phlorotannins-enriched extracts for wound healing

Brown seaweeds are recognized sources of compounds with a wide range of properties and applications. Within these compounds, phlorotannins are known to possess several bioactivities (e.g., antioxidant, anti-inflammatory, and antimicrobial) with potential to improve wound healing. To obtain phlorotannins enriched extracts from Undaria pinnatifida, a biorefinery was set using lowcost industry-friendly methodologies, such as sequential solid–liquid extraction and liquid–liquid extraction. The obtained extracts were screened for their antioxidant and antimicrobial activity against five common wound pathogens and for their anti-inflammatory potential. The ethanolic wash fraction (wE100) had the highest antioxidant activity (114.61 +- 10.04 mmol mg-1 extract by Diphenyl-1-picrylhydrazyl (DPPH) and 6.56 +-1.13mMeq. Fe II mg-1 extract by and Ferric Reducing Antioxidant Power (FRAP)), acting efficiently against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria, and showing a nitric oxide production inhibition over 47% when used at 0.01 ug mL-1. NMR and FTIR chemical characterization suggested that phlorotannins are present. Obtained fraction wE100 proved to be a promising candidate for further inclusion as wound healing agents, while the remaining fractions analyzed are potential sources for other biotechnological applications, giving emphasis to a biorefinery and circular economy framework to add value to this seaweed and the industry.info:eu-repo/semantics/publishedVersio

Cosmeceutical potential of grateloupia turuturu: using low-cost extraction methodologies to obtain added-value extracts

The invasive macroalga Grateloupia turuturu is known to contain a diversity of bioactive compounds with different potentialities. Among them are compounds with relevant bioactivities for cosmetics. Considering this, this study aimed to screen bioactivities with cosmeceutical potential, namely, antioxidant, UV absorbance, anti-enzymatic, antimicrobial, and anti-inflammatory activities, as well as photoprotection potential. Extractions with higher concentrations of ethanol resulted in extracts with higher antioxidant activities, while for the anti-enzymatic activity, high inhibition percentages were obtained for elastase and hyaluronidase with almost all extracts. Regarding the antimicrobial activity, all extracts showed to be active against E. coli, S. aureus, and C. albicans. Extracts produced with higher percentages of ethanol were more effective against E. coli and with lower percentages against the other two microorganisms. Several concentrations of each extract were found to be safe for fibroblasts, but no photoprotection capacity was observed. However, one of the aqueous extracts was responsible for reducing around 40% of the nitric oxide production on macrophages, showing its anti-inflammatory potential. This work highlights G. turuturu’s potential in the cosmeceutical field, contributing to the further development of natural formulations for skin protection.info:eu-repo/semantics/publishedVersio

Boat noise impacts Lusitanian toadfish breeding males and reproductive outcome

Anthropogenic noise is a growing threat to marine organisms, including fish. Yet very few studies have addressed the impact of anthropogenic noise on fish reproduction, especially in situ. In this study, we investigated the impacts of boat noise exposure in the reproductive success of wild Lusitanian toadfish (Halobatrachus didactylus), a species that relies on advertisement calls for mate attraction, using behavioural, physiological and reproductive endpoints. Two sets of artificial nests were deployed in the Tagus estuary and exposed to either ambient sound or boat noise during their breeding season. Toadfish males spontaneously used these nests to breed. We inspected nests for occupation and the presence of eggs in six spring low tides (in two years) and assessed male vocal activity and stress responses. Boat noise did not affect nest occupation by males but impacted reproductive success by decreasing the likelihood of receiving eggs, decreasing the number of live eggs and increasing the number of dead eggs, compared to control males. Treatment males also showed depressed vocal activity and slightly higher cortisol levels. The assessment of oxidative stress and energy metabolism-related biomarkers revealed no oxidative damage in noise exposed males despite having lower antioxidant responses and pointed towards a decrease in the activity levels of energy metabolism-related biomarkers. These results suggest that males exposed to boat noise depressed their metabolism and their activity (such as parental care and mate attraction) to cope with an acoustic stressor, consistent with a freezing defensive response/behaviour. Together, our study demonstrates that boat noise has severe impacts on reproductive fitness in Lusitanian toadfish. We argue that, at least fishes that cannot easily avoid noise sources due to their dependence on specific spawning sites, may incur in significant direct fitness costs due to chronic noise exposure.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Gene Expression Responses Linked to Reproduction Effect Concentrations (EC10,20,50,90) of Dimethoate, Atrazine and Carbendazim, in Enchytraeus albidus

BACKGROUND: Molecular mechanisms of response to pesticides are scarce and information on such responses from soil invertebrates is almost inexistent. Enchytraeus albidus (Oligochaeta) is a standard soil ecotoxicology model species for which effects of many pesticides are known on survival, reproduction and avoidance behaviour. With the recent microarray development additional information can be retrieved on the molecular effects. METHODOLOGY/PRINCIPAL FINDINGS: Experiments were performed to investigate the transcription responses of E. albidus when exposed to three pesticides - dimethoate (insecticide), atrazine (herbicide) and carbendazim (fungicide) - in a range of concentrations that inhibited reproduction by 10%, 20%, 50% and 90% (EC(10), EC(20), EC(50) and EC(90), respectively). The goal of this study was to further identify key biological processes affected by each compound and if dose-related. All three pesticides significantly affected biological processes like translation, regulation of the cell cycle or general response to stress. Intracellular signalling and microtubule-based movement were affected by dimethoate and carbendazim whereas atrazine affected lipid and steroid metabolism (also by dimethoate) or carbohydrate metabolism (also by carbendazim). Response to DNA damage/DNA repair was exclusively affected by carbendazim. CONCLUSIONS: Changes in gene expression were significantly altered after 2 days of exposure in a dose-related manner. The mechanisms of response were comparable with the ones for mammals, suggesting across species conserved modes of action. The present results indicate the potential of using gene expression in risk assessment and the advantage as early markers