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

Exposure to the insecticide sulfoxaflor affects behaviour and biomarkers responses of Carcinus maenas (Crustacea: Decapoda)

Sulfoxaflor is an insecticide belonging to the recent sulfoximine class, acting as a nicotinic acetylcholine receptor (nAChRs) agonist. There are few studies regarding sulfoxaflor’s toxicity to non-target organisms. The present study aimed to investigate the acute and sub-lethal effects of sulfoxaflor on Carcinus maenas by addressing survival, behaviour (feed intake and motricity), and neuromuscular, detoxification and oxidative stress, and energy metabolism biomarkers. Adult male green crabs were exposed to sulfoxaflor for 96 h and an LC50 of 2.88 mg L1 was estimated. All biomarker endpoints were sampled after three (T3) and seven (T7) days of exposure and behavioural endpoints were addressed at T3 and day six (T6). Sulfoxaflor affected the feed intake and motricity of C. maenas at T6. From the integrated analysis of endpoints, with the increase in concentrations of sulfoxaflor, after seven days, one can notice a lower detoxification capacity (lower GST), higher LPO levels and effects on behaviour (higher motricity effects and lower feed intake). This integrated approach proved to be valuable in understanding the negative impacts of sulfoxaflor on green crabs, while contributing to the knowledge of this pesticide toxicity to non-target coastal invertebrates.info:eu-repo/semantics/publishedVersio

Early neonatal echocardiographic findings in an experimental rabbit model of congenital diaphragmatic hernia

This study aimed to demonstrate that congenital diaphragmatic hernia (CDH) results in vascular abnormalities that are directly associated with the severity of pulmonary hypoplasia and hypertension. These events increase right ventricle (RV) afterload and may adversely affect disease management and patient survival. Our objective was to investigate cardiac function, specifically right ventricular changes, immediately after birth and relate them to myocardial histological findings in a CDH model. Pregnant New Zealand rabbits underwent the surgical procedure at 25 days of gestation (n=14). CDH was created in one fetus per horn (n=16), and the other fetuses were used as controls (n=20). At term (30 days), fetuses were removed, immediately dried and weighed before undergoing four-parameter echocardiography. The lungs and the heart were removed, weighed, and histologically analyzed. CDH animals had smaller total lung weight (P<0.005), left lung weight (P<0.005), and lung-to-body ratio (P<0.005). Echocardiography revealed a smaller left-to-right ventricle ratio (LV/RV, P<0.005) and larger diastolic right ventricle size (DRVS, P<0.007). Histologic analysis revealed a larger number of myocytes undergoing mitotic division (186 vs 132, P<0.05) in CDH hearts. Immediate RV dilation of CDH hearts is related to myocyte mitosis increase. This information may aid the design of future strategies to address pulmonary hypertension in CDH

Brain caspase-3 and intestinal FABP responses in preterm and term rats submitted to birth asphyxia

Neonatal asphyxia can cause irreversible injury of multiple organs resulting in hypoxic-ischemic encephalopathy and necrotizing enterocolitis (NEC). This injury is dependent on time, severity, and gestational age, once the preterm babies need ventilator support. Our aim was to assess the different brain and intestinal effects of ischemia and reperfusion in neonate rats after birth anoxia and mechanical ventilation. Preterm and term neonates were divided into 8 subgroups (n=12/group): 1) preterm control (PTC), 2) preterm ventilated (PTV), 3) preterm asphyxiated (PTA), 4) preterm asphyxiated and ventilated (PTAV), 5) term control (TC), 6) term ventilated (TV), 7) term asphyxiated (TA), and 8) term asphyxiated and ventilated (TAV). We measured body, brain, and intestine weights and respective ratios [(BW), (BrW), (IW), (BrW/BW) and (IW/BW)]. Histology analysis and damage grading were performed in the brain (cortex/hippocampus) and intestine (jejunum/ileum) tissues, as well as immunohistochemistry analysis for caspase-3 and intestinal fatty acid-binding protein (I-FABP). IW was lower in the TA than in the other terms (P<0.05), and the IW/BW ratio was lower in the TA than in the TAV (P<0.005). PTA, PTAV and TA presented high levels of brain damage. In histological intestinal analysis, PTAV and TAV had higher scores than the other groups. Caspase-3 was higher in PTAV (cortex) and TA (cortex/hippocampus) (P<0.005). I-FABP was higher in PTAV (P<0.005) and TA (ileum) (P<0.05). I-FABP expression was increased in PTAV subgroup (P<0.0001). Brain and intestinal responses in neonatal rats caused by neonatal asphyxia, with or without mechanical ventilation, varied with gestational age, with increased expression of caspase-3 and I-FABP biomarkers

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 responses

Marine invasive species for high-value products' exploration: Unveiling the antimicrobial potential of Asparagopsis armata against human pathogens

Infectious diseases remain one of the leading global causes of death, mainly due to the increasing number of multi-resistant microorganisms. Therefore, novel antimicrobials are continuously needed. Marine organisms have already proven to be a rich source of bioactive compounds which can be used for the development of novel pharmacological drugs. Within these, seaweeds are an important resource still underexplored. Asparagopsis armata is a marine invasive seaweed that has spread along several coastlines of the world, inducing negative pressures in marine ecosystems. Therefore, it is crucial to develop strategies to counteract their impacts. In this work, A. armata was extracted with methanol and dichloromethane (1:1) and fractionated by column chromatography with different polarity solvents, providing 8 fractions (F1-F8). All the fractions were evaluated for their antimicrobial potential against important human pathogens, namely Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, and Candida albicans. Additionally, their capacity to inhibit biofilms formation and the effects on cytoplasmatic membrane and DNA integrity were also assessed. The most active fractions were further purified and submitted to GC–MS analysis. The results showed that A. armata produces compounds with a high inhibitory activity against S. aureus, P. aeruginosa, and C. albicans growth, possibly mediated by cytoplasmatic membrane disruption and DNA damage. GC–MS analysis suggested that the most active fractions were mainly composed of bromoditerpenes and fatty acids. The attained results point to the relevance of the invasive A. armata as a source of antimicrobial substances with broad-spectrum activity. The use of invasive species to obtain natural bioactive compounds presents a two-folded opportunity - high availability of the biological material for the extraction of bioactive compounds and, through specimen collection, the mitigation of the negative effects caused by invasive species, contributing to ecosystem integrity and sustainability.info:eu-repo/semantics/publishedVersio