24-h Exposure Research Articles

Effects of diuron and two of its metabolites in biochemical markers and behavior of zebrafish larvae.

Diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is an herbicide used in many crops, including sugar cane cultivation. It is commonly found in aquatic ecosystem and is of high concern due to its ability to persist in the environment. Diuron metabolites include DCA (3,4-dichloroaniline) and DCPMU (3-(3,4-dichlorophenyl-1-methylurea). The objective of this study was to evaluate the effects of diuron and two of its metabolites in zebrafish (Danio rerio) developing embryos, from biochemical to individual level. Activities of the enzymes acetylcholinesterase (AChE), catalase (CAT), glutathione-S-transferase (GST), andlactate dehydrogenase (LDH) and the levels of lipid peroxidation (LPO), swimming activity, and body length were investigated after an exposure of 120h, and the heart rate was determined after 48h of exposure. The range of concentrations tested was 0.003-3.000mg/L diuron, 0.020-1.500mg/L DCA, and 0.020-2.100mg/L DCPMU. Results showed that AChE activity was inhibited by diuron (3.000mg/L) and DCPMU (0.326, 0.828mg/L). However, the swimming activity of fish larvae exposed to diuron or its metabolites was not affected. The CAT was induced by DCPMU, and GST was induced by diuron. This suggests that CAT is acting to cope with oxidative stress induced by DCPMU and GST might have a role in the detoxification of diuron. In addition, larvae exposed to DCA (0.633 and 1.500mg/L) had a reduction in their length, and larvae exposed to diuron (0.754 and 3.000mg/L) and DCA (0.267, 0.633, and 1.500mg/L) presented bradycardia, suggesting cardiotoxicity. Overall, results indicate that diuron, DCA, or DCPMU induces adverse effects during the early phases of zebrafish development, such as the impairment of neurotransmission and cardiovascular function and alterations in antioxidant enzymes and growth. Diuron appeared as more toxic than its metabolites since the lowest LOEC (0.012mg/L) and higher integrated biomarker response (IBR) values were obtained with exposure to this herbicide. Furthermore, as it is fast degraded into DCA and DCPMU, which also affected the zebrafish developing embryos at environmentally relevant concentrations, its use might be of concern in ecosystems that receive agriculture runoff due to their potential adverse effects to aquatic biota.

The Effect of Boric Acid and Calcium Fructoborate on T Helper Cell Differentiation by Influencing Foxp3 and Ror-γt in Rheumatoid Arthritis and Systemic Lupus Erythematosus.

Many animal and human studies indicate that boric acid and calcium fructoborate have effects on helper T cells in immunity. The aim of our study is to evaluate the effects of boric acid and calcium fructoborate on Treg (CD4+Foxp3+) and Th17 (CD4+Ror-γt+) cell populations and related cytokine levels in mononuclear cells isolated from peripheral blood samples of rheumatoid arthritis and systemic lupus erythematosus patients. Newly diagnosed rheumatoid arthritis (n = 10) patients, systemic lupus erythematosus (n = 5) patients, and healthy individuals (n = 9) were included in this study. Consent forms were obtained from all individuals participating the study, blood samples were taken, and peripheral blood mononuclear cells were isolated. Isolated cells were exposed to low-dose and high-dose boric acid and calcium fructoborate in cell culture. Treg and Th17 cell populations were analyzed by flow cytometry after 48h of exposure. IL-2, IL-6, IL-17, IL-23, TNF-α, and TGF-β levels in the culture medium were tested by ELISA method. At the end of the study, in healthy controls, high-dose BA improved the Treg/Th17 population but could not display similar effects on RA and SLE group. However, both boric acid and calcium fructoborate at different doses showed an increasing effect on Ror-γt in RA and SLE group. Different doses of BA and CaF treatment found to have a variable effect on cytokine. Both BA and CaF in low doses decreased TNF-α levels in RA group which shows that these boron compounds could contribute positively to the treatment of autoimmune diseases.

Thiazepine-based Hybrids as Promising Anti-colon Cancer Agents: Design, Synthesis, Computational and In Vitro Screening.

Novel thiazepine-based hybrids (9a-d) were designed and synthesized to create lead molecules with exceptional anti-colon cancer efficacy. Analytical methods, including IR, NMR, and HR-MS, characterized the synthesized compounds. The in vitro colorectal study was carried out to compare the biological activity of newly developed compounds with the computational data. The tested compounds induced cytotoxicity in HT-29 cells for both 24h and 48h in a dose-dependent manner. However, compound 9a induced cytotoxicity at much higher concentrations compared to the rest of the compounds. 9b and 9c caused 50% cell death (compared to the untreated cells) at a dose of ~ 50µM and 40 µM in case of 24-hour exposure, respectively. On the contrary, for 48h exposure, both 9b and 9c induced 50% cell death concerning untreated cells at a dose of around ~20 µM, whereas 9d exhibited 50% cell death at 5 µM in the case of 48 h exposure. In silico ADMET was also carried out to understand the pharmacokinetics and safety profiles of the drug candidates. We found some of the critical targets of these compounds, which eventually will be integral to exploring the mechanistic actions of these compounds in colon cancer.

Establishment of the first dermal fibroblast cell line derived from the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) and its response to pollutant exposure

The Indo-Pacific bottlenose dolphin (Tursiops aduncus), classified as a new species since 1998, is underexplored in ecotoxicology owing to ethical constraints and the lack of specific in vitro models. Herein, we established the first skin fibroblast cell line (TaSF) from an Indo-Pacific bottlenose dolphin stranded along the Pearl River Estuary, China. TaSF cells exhibited strong proliferation in early passages but ceased mitosis at passage 19, likely owing to reaching the Hayflick limit. Morphology and immunofluorescence tests confirmed the fibroblastic nature of these cells. Karyotyping revealed 21 pairs of autosomes and 1 pair of sex chromosomes (XY), consistent with many cetaceans. To facilitate long-term future studies, TaSF cells were immortalized with exogenous simian virus 40 T antigen, creating the TaSFT cell line. The cytotoxic effects of 27 contaminants, including 6 organotins (OTs), 10 per- and polyfluoroalkyl substances (PFASs), and 11 phthalates (PAEs), on TaSFT cells were evaluated after 24-h exposure. Among these chemicals, OTs exhibited the strongest cytotoxicity, and both OTs and PFASs showed structure-related toxicity. These findings confirm the feasibility of TaSFT cells as a novel tool for ecotoxicity research on the Indo-Pacific bottlenose dolphin and highlight the need for further investigation into the environmental contaminant pressures on this species.

Acute freshwater CO2 exposure does not impair seawater transfer in three different sizes of Atlantic salmon (Salmo salar) subjected to different photoperiod manipulations.

There is a growing interest in Atlantic salmon (Salmo salar) aquaculture to extend the time fish are reared in freshwater (FW) recirculating aquaculture systems (RAS), producing larger FW salmon that can then be induced to undergo smoltification before transfer into marine net pens for grow-out and harvest. Smolts can be produced by photoperiod (PT) manipulation in RASs, but little is known about how delaying smoltification to larger body sizes affects susceptibility to elevated CO2 levels (hypercapnia), which can occur at high stocking densities in FW RAS or during transport from FW RAS rearing facilities to marine net pens. To address this, Atlantic salmon were reared from hatch to one of three different sizes (~230, ~580, or ~1300 g) in FW (3 ppt) under continuous light (24:0, light:dark). Once fish reached the desired sizes, a group of salmon were maintained on continuous light 24L:0D to serve as a control salmon. A second group of salmon were exposed to 8 weeks of 12L:12D and then to 4 weeks of 24L:0D to serve as PT treatment salmon, which is the PT manipulation commonly used in Atlantic salmon aquaculture to induce smoltification. At the end of PT manipulation, both control and PT treatment salmon were exposed to 0% or 1.5% CO2 (30 mg/L) for 96 h in FW and then transferred to air-equilibrated seawater (SW, 35 ppt, normocapnia). Salmon were sampled at the end of the 96-h FW CO2 exposure and at 24 h and 7 days in SW for measurements of blood ion/acid-base status, muscle water content (MWC), and gill and kidney Na+/K+ ATPase (NKA) activity. Exposure to 96 h of CO2 in FW resulted in acid-base disturbances in fish from all three size classes, with decreases in blood pH and increases in blood PCO2 and plasma [HCO3 -] but no mortality. Despite these large acid-base disturbances in FW, after transfer to normocapnic SW, there were no significant effects of CO2 exposure on extracellular blood pH, intracellular red blood cell pH, or plasma osmoregulatory status for all three sizes of post-smolt salmon. In general, SW transfer was associated with significant increases in plasma ions and osmolality, as well as gill and kidney NKA activity after 24 h and 1 week in SW with no significant impacts between different sizes of salmon. Thus, exposure to 30 mg CO2/L that mimics levels experienced during transport from FW RAS to an SW transfer site may have minimal effects on Atlantic salmon smolts up to 1300 g.

Acute Toxicity and IN VIVO Antischistosomal Effects of Entada africana Guill & Perott (Fabaceae) Methanol Stem Bark Extract in Albino Mice

The study was aimed at determining the acute toxicity and schistosomicidal effects of methanol extract (ME) of Entada africana (E. africana), in albino mice. Fresh stem bark of E. africana was shade-dried and extracted by Soxhlet extraction. Acute toxicity was carried out on 6 groups of mice (n=3) of 6-week-old, sizes 27-30g; to determine the therapeutic index, piloerection signs and possible mortality (LD50) in 24h exposure period. Cercaria from B. globosus snails were shed under a 100W bulb for 2 hours. In vivo antischistosomal assays was by used of 6-weeks old (27-30g) mice. Set I (n=10) involved investigation on schistosomules infection in the mice, 3-7 days post infection (PI). Set II (n=10) was infected and treated with E. africana ME extract, at concentrations 10-100mg/l, 35th day, PI for 5 consecutive days. Set III (n=10), were infected and treated with praziquantel– PZQ (positive control). While set IV (n=10) were infected and untreated (negative control). All were sacrificed, 75th day of PI. Data were analyzed by GraphPad® prism 8.4, version 2020. Findings revealed that E. africana ME did not generate any harmful or clinical effect within 24h, post administration; and there were no obvious reactions such as paw licking, stooling, piloerection or immediate death, except at phase II, 5000mg/kg bwt, (1⁄3) being the highest dosage. Worm burden decreased with increase in concentrations, especially at 70-100mg/l. Lower concentrations (10mg/l), had high worm population (76.00±21.28). Infected and untreated group had highest worm population (189.67±32.52). E. africana ME stem bark extract, showed antischistosomal effect and worm reduction in a dose- dependent pattern.

Heavy metal accumulation and interaction dynamics in Brachidontes pharaonis: a bioindicator study in the Red Sea.

This work evaluates utilizing the native mussel Brachidontes pharaonis as a bioindicator and sentinel organism for monitoring heavy metals Cu, Zn, and Cd along the Red Sea coast of Egypt. Samples were collected from four coastal locations, and the concentrations of heavy metals in the mussels' tissues, shells, seawater, and sediments were analyzed. Subsequently, bioassay experiments were conducted by exposing the organisms to single, binary, and tertiary metal mixtures, and the accumulation of heavy metals was determined to elucidate the dynamics of metal-metal interactions. Field samples revealed significant variations in heavy metal concentrations in the mussels' soft tissues across different locations, with Zn ranging from 58.1 to 121.0µg/g dw (dry weight), Cu ranging between 18.3 and 36.7µg/g dw, and Cd ranging from 0.3 to 1.04µg/g dw. Conversely, the shells exhibited minimal spatial variations, with much lower contents of Cu (ranging from 1.9 to 2.8µg/g dw) and Zn (ranging from 1.8 to 1.9µg/g dw). However, the shells accumulated Cd at higher levels (ranging from 1.4 to 2.1µg/g dw) compared to the soft tissues. Following a 96-h bioassay experiment, the soft tissues displayed a linear accumulation of metals with increasing exposure dose, with Cd showing the highest accumulation rate (approximately threefold) followed by Zn (twofold) and Cu (1.7-fold). In binary and tertiary exposures, the metals exhibited a general antagonistic interaction, affecting each other's accumulation. On the other hand, the accumulation of heavy metals in the shells after the 96-h bioassay exposure did not follow a consistent linear pattern, suggesting that accumulation during this short experimental period occurs primarily through adsorption rather than the biological pathway.

Fabrication of bamboo nanocellulose fibril-based food packaging with dual-antimicrobial property

The development of cellulose-based packaging films with excellent antimicrobial properties and biocompatibility has garnered significant attention. In this work, nanocellulose fibrils (NCFs) derived from from bamboo parenchyma cells were utilized to fabricate nanocomposite film with antimicrobial properties. This system exhibited distinct release behaviors for two antimicrobial agents, with the slow release of Ag nanoparticle (AgNP) in the initial stage contributed to delaying food spoilage, while the subsequent pH change in the microenvironment facilitated the release of essential oil of sour orange blossoms (SEO) for secondary antimicrobial activity. Additionally, the composite film demonstrated improved thermal stability and UV blocking capacity. Moreover, AgNP has been proven to enhance the mechanical properties, with the tensile strength of the novel composite film increasing by 34.85 % compared to control group. The water vapor permeability and oxygen permeability of the novel composite film were reduced, which could potentially reduce weight loss and slow down the rate of after-ripening. Following the acidification treatment, the films containing EO@MPN (essential oil encapsulated with metal-polyphenol network) component performed different antimicrobial patterns, indicating their pH-responsive antimicrobial capabilities, and they are effective against both Gram-positive and Gram-negative bacteria. After a 24-h exposure to a food simulant, the release amount of Ag was measured at 67.6 μg/dm2, within the acceptable limit, and the release profile of Ag was characterized. Cytotoxicity and Live/Dead staining tests confirmed that the novel composite film film had no significant toxicity, thus making it safe for application in food preservation. Furthermore, in a 15-day preservation experiment with mangoes, the novel composite film demonstrated the best performance, underscoring its potential as a sustainable antimicrobial packaging material.

In vitro cytotoxicity evaluation of green synthesized alumina nanoscales on different mammalian cell lines

Nanoscale research is gaining interest in the biomedical, engineering, and environmental fields. Current expensive traditional chemical methods for synthesizing nanoparticles (NPs) inevitably lead to the synthesis of NPs with potentially less or no toxic effects on living cells. To overcome these challenges, in this study, we use a simple, inexpensive, and less toxic one-pot green chemistry approach instead of a chemical method to synthesize alumina nanoparticles (AlNPs) from Carica papaya extract. Nano-alumina has been widely studied due to its remarkable biological and physiochemical properties at nanoscale. However, to date, its biomedical application is limited due to the lack of sufficient data on cytotoxicity in living cells. The physicochemical properties of nano-alumina were determined by FT-IR, DLS, SEM and HRTEM. The cytotoxic effects of the synthesized nano-alumina were studied in cell lines LT and VERO at concentrations of 10–480 µg/mL in vitro. The cell viability of nano-alumina was evaluated using the MTT assay and the AO /EB double staining technique. Our results based on DLS and HRTEM analyzes confirmed spherical AlNPs with a zeta potential and average particle size of − 25 to 5 mV and 52 nm, respectively. The nano-alumina tested showed low toxicity to both cell lines after 28- and 48-h exposure. Furthermore, cell viability statistically decreased with increasing incubation time and concentration of AlNPs up to 480 μg/mL (p < 0.001). However, a minimal increase in cytotoxicity was observed at threshold levels in the range of 120–480 µg/mL. The half-maximal inhibitory concentration (IC50) of AlNPs in the VERO and LT cell lines were 153.3, 252.0 µg/mL and 186.6, 395.3 µg/mL, respectively, after 24- and 48-h exposure to AlNPs. Thus, we conclude that the cytotoxic effect of AlNPs depends on the concentration, exposure time and cell type. The result suggests that the concentration used in this study may be useful for biomedical applications.

Individual-level noise exposure and its association with sleep quality and duration: A cross-sectional study using real-time data

As urban populations grow, the problem of noise pollution becomes more significant. The limited number of epidemiological studies linking individual-level dynamic noise exposure to sleep highlights a gap in our understanding of how individual-level noise exposure impact sleep quality and duration. A cross-sectional survey was conducted in Hong Kong, and portable noise sensors were used to record participants' real-time noise exposure. The Pittsburgh Sleep Quality Index was used to assess their sleep quality. Logistic regression was used to examine the relationship of individual-level noise exposure with sleep quality and sleep duration. Among a total of 763 subjects included in the analysis, and a-weighted decibels [dB(A)] 24-h average exposure (L24) was 63.21 (58.85–67.85) dB(A) for workday and 63.52 (59.03–67.86) dB(A) for non-workday. A significant decrease in individual noise level was observed closer to bedtime (P < 0.05). Compared with the lowest noise exposure, exposure to the highest noise level was positively associated with the presence of poor sleep quality for L24, Ld and Ln, with an odds ratio (OR) and 95 % confidential interval (CI) of 1.53 (1.04–2.24), 1.65 (1.12–2.43), and 1.51 (1.03–2.21), respectively. Exposure to elevated noise level was associated with increased risk of shorter nocturnal sleep duration (< 7 h), the OR and 95 % CI was 1.87 (1.29–2.73) for L24, 1.58 (1.09–2.30) for Ld, 1.50 (1.03–2.18) for Le, and 1.60 (1.10–2.32) for Ln in the highest noise exposure group. Similar findings were observed both on workdays and non-workdays, respectively. Furthermore, the results showed that each 10 dB(A) increment in L24 and Ln was associated with a probable 29 % and 27 % increase in poor sleep quality and a 24 % and 24 % reduction in sleep duration. This study demonstrates that environmental noise exposure was associated with poor sleep quality and shorter sleep duration, posing a significant public health issue in Hong Kong.

Lack of effects of polystyrene micro- and nanoplastics on activity and expression of human drug transporters

Micro- and nanoplastics (MPs/NPs) constitute emerging and widely-distributed environmental contaminants to which humans are highly exposed. They possibly represent a threat for human health. In order to identify cellular/molecular targets for these plastic particles, we have analysed the effects of exposure to manufactured polystyrene (PS) MPs and NPs on in vitro activity and expression of human membrane drug transporters, known to interact with chemical pollutants. PS MPs and NPs, used at various concentrations (1, 10 or 100µg/mL), failed to inhibit efflux activities of the ATP-binding cassette (ABC) transporters P-glycoprotein, MRPs and BCRP in ABC transporter-expressing cells. Furthermore, PS particles did not impair the transport of P-glycoprotein or BCRP substrates across intestinal Caco-2 cell monolayers. Uptake activities of solute carriers (SLCs) such as OCT1 and OCT2 (handling organic cations) or OATP1B1, OATP1B3, OATP2B1, OAT1 and OAT3 (handling organic anions) were additionally not altered by PS MPs/NPs in HEK-293 cells overexpressing these SLCs. mRNA expression of ABC transporters and of the SLCs OCT1 and OATP2B1 in Caco-2 cells and human hepatic HepaRG cells were finally not impaired by a 48-h exposure to MPs/NPs. Altogether, these data indicate that human drug transporters are unlikely to be direct and univocal targets for synthetic PS MPs/NPs.

Effects of diphenhydramine on crayfish cytochrome P450 activity and antioxidant defence mechanisms: First evidence of CYP2C- and CYP3A-like activity in marbled crayfish

Growing evidence has reported that diphenhydramine (DPH), an ionisable antihistamine, is widely present in surface waters across the world. Relative to vertebrates studied, its impact on invertebrates, particularly concerning cytochrome P450 (CYP) metabolism and oxidative stress, remains poorly understood. In this study, we aimed to investigate the effects of 2, 20, and 200 µg/L DPH on marbled crayfish (Procambarus virginalis) after 96-h exposure. Specifically, we assessed CYP activity, antioxidant enzyme responses, and acetylcholinesterase (AChE) activity in gills, muscle, and hepatopancreas. The crayfish CYP metabolised fluorogenic CYP-metabolic substrates of 7-benzyloxy-4-trifluoromethylcoumarin (BFC) and dibenzylfluorescein (DBF), which evidenced the activity of CYP2C and CYP3A isoforms, well known in mammalian detoxification metabolism. Both BFC and DBF dealkylations showed a positive correlation with each other but were negatively correlated to water and haemolymph DPH concentrations. Exposure to 200 µg/L DPH elicited an apparent inhibition trend, albeit not significant, in BFC- and DBF-transformation activities in crayfish. Other tested 7-benzyloxyresorufin and 7-pentoxyresorufin substrates were poorly metabolised, suggesting their relatively low activity or the lack of mammalian-like CYP1A and CYP2B isoforms in marbled crayfish. The significant modulation of antioxidant enzymes was demonstrated in gills and hepatopancreas. The exposure to DPH did not alter the activity of AChE. Integrated biomarker response version 2 showed the highest cumulative effect of DPH exposure on gills, implying that gill tissue is the most reliable matrix for evaluating DPH toxicity. Activities of glutathione peroxidase and glutathione-S-transferase were the most deviated determinants among the investigated biomarkers, providing insights into the DPH toxicity in crayfish. This study brought the first insight into utilising the fluorogenically active substrates BFC and DBF to demonstrate the CYP involvement in the detoxification metabolism in marbled crayfish. Further, our results provided information on valuable antioxidant defence mechanisms and biomarker responses for a future DPH toxicity assessment in aquatic organisms.

Unraveling the toxicity mechanisms of nanoplastics with various surface modifications on Skeletonema costatum: Cellular and molecular perspectives

Nanoplastics are ubiquitous in marine environments, exhibiting high bioavailability and potential toxicity to marine organisms. However, the impacts of nanoplastics with various surface modifications on marine microalgae remain largely unexplored. This study explored the toxicity mechanisms of two nanoplastic types-polystyrene (PS) and polymethyl methacrylate (PMMA)-with distinct surface modifications on Skeletonema costatum at cellular and molecular levels. Results showed that nanoplastics significantly impaired the growth of microalgae, particularly PS-NH2, which caused the most pronounced growth inhibition, reaching 56.99 % after a 96-h exposure at 50 mg/L. Transcriptomic profiling revealed that nanoplastics disrupted the expression of genes predominantly involved in ribosome biogenesis, aminoacyl-tRNA biosynthesis, amino acid metabolism, and carbohydrate metabolism pathways. The integrated biochemical and transcriptomic evidence highlighted that PS-NH2 nanoplastics had the most adverse impact on microalgae, affecting fundamental pathways such as ribosome biogenesis, energy metabolism, photosynthesis, and oxidative stress. Our findings underscore the influence of surface-modified nanoplastics on algal growth and contribute new understanding to the toxicity mechanisms of these nanoplastics in marine microalgae, offering critical information for assessing the risks of emerging pollutants.

Evaluating the Efficacy of Plant Extracts in Managing the Bruchid Beetle, Callosobruchus maculatus (Coleoptera: Bruchidae).

An estimated 2000 plant species have been employed for pest control worldwide. The use of these botanical derivatives is thought to be one of the most cost-effective and sustainable options for pest management in stored grain. The present study was designed to assess the efficacy of five plant extracts viz; Nicotiana tabacum L., Nicotiana rustica L., Azadirachta indica A. Juss., Thuja orientalis L., and Melia azedarach L. against Callosobruchus maculatus L. Plant species extracts were applied at six different concentrations, i.e., 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0% in four replications. The phytochemical analyses of ethanolic extracts of five plant species showed variable amounts of phytochemicals i.e., alkaloids, flavonoids, saponins, diterpenes, phytosterol, and phenols. Total phenolic and flavonoid compounds were also observed. The efficacy of A. indica was highest, characterized by the lowest infestation rate (16.65%), host seed weight loss (7.85%), mean oviposition (84.54), and adult emergence (58.40%). In contrast, T. orientalis was found to be the least effective against C. maculatus, with the highest infestation rate of 25.60%, host seed weight loss of 26.73%, mean oviposition of 117.17, and adult emergence rate of 82.01%. Probit analysis was performed by estimating LC50 and LC90. The toxicity percentages of N. tabacum (LC50 = 0.69%, LC90 = 14.59%), N. rustica (LC50 = 0.98%, LC90 = 22.06%), and A. indica (LC50 = 1.09%, LC90 = 68.52%) were notable in terms of the lower LC50 and LC90 values after the 96-h exposure period against C. maculatus. Repellency was assessed by using the area preference and filter paper method. The repellency of C. maculatus on plant extracts increased with the increasing dose and time, such that it was the highest after 48 h. Likewise, at a 3% concentration, A. indica demonstrated 100.00% (Class-V) repellency followed by N. tabacum (96.00%, Class-V), N. rustica (74%, Class-IV), M. azedarach (70.00%, Class-IV), and T. orientalis (68.00%, Class-IV). Based on the findings of this study, we recommend integrating N. rustica, N. tabacum, A. indica, and M. azedarach for effective management of C. maculatus and highlight the potential of these plant species in the formulation of new biocidal agents.

Multi-targeted action of rooibos may protect against ischaemic stroke-induced neurological deficit and endothelial dysfunction

Ethnopharmacological relevanceIndigenous use communities in the Western Cape (South Africa) where Aspalathus linearis (Brum.f) R.Dahlgren - or rooibos - grows naturally, has a long history of using rooibos for medicinal purposes. Apart from its well-known antioxidant effect, the Cederberg community in particular has been using rooibos as a treatment for high blood pressure. Given the detrimental effects of high blood pressure on endothelial cells, rooibos may either directly or indirectly affect vascular health. This, together with more recent reports of neuroprotective effects, may position rooibos as complementary medicine in related vascular conditions such as ischaemic stroke. Aims of the studyThe study aimed to evaluate the potential benefit of acute administration of unfermented rooibos, on vascular health in a larval zebrafish model of stroke. Materials and methodsStroke was induced via 24-h ponatinib exposure, in the presence or absence of an aqueous solution of an ethanolic extract of unfermented Rooibos (GreenOxithin™). The magnitude of stroke was assessed by monitoring larval locomotion and thrombus formation. In terms of specific mechanisms probed, changes in redox status (MDA and TEAC), neurological markers (TH and NeuroD1) and endothelial health (tight/adhesion junction protein expression) were assessed. ResultsRooibos treatment limited thrombus formation and prevented stroke-induced deficits on larval motility. In terms of redox status, rooibos treatment prevented lipid peroxidation 3 days after initial stroke induction, reducing the need for significant upregulation of endogenous antioxidant mechanisms. Stroke-induced changes in neuronal (NeuroD1 and TH) protein expression were normalized in the presence of rooibos, suggesting a neuroprotective role. In terms of tight junction proteins, stroke-related decreases in ZO-1 expression were again prevented by rooibos treatment. In addition, rooibos treatment may beneficially modulate levels of claudin-5 and VE-cadherin, to indirectly limit stroke-associated vascular dysfunction. ConclusionsTaken together, activity data and physiological assessments suggest that unfermented rooibos may indeed have benefit in the context of stroke, via action at multiple targets. Thus, current data further our understanding of the mechanisms of actions of rooibos and warrant future research to confirm sufficient bioavailability of rooibos in target tissues, in mammalian systems.

Pathological and oxidative stress responses of Mytilus galloprovincialis to Vibrio mediterranei infection: An in vivo challenge

Since the identification of Vibrio mediterranei as a causative agent in mass mortalities of pen shells across the Mediterranean, elucidating its pathogenicity, virulence, and interactions with other bivalves has gained importance. While the cellular and immune responses of bivalves to various Vibrio species have been extensively studied, the infectious characteristics of this Vibrio species, particularly in the context of pen shell outbreaks, remain unclear for other bivalves. Therefore, to evaluate its pathogenicity, we investigated the histological and oxidative effects on the Mediterranean mussel (Mytilus galloprovincialis), a key species in aquaculture. Two distinct infection setups were established: one involving the inoculation of seawater with the bacterial isolate and another involving direct injection of the bacteria into the mussels. After a 24-h exposure period, histological evaluations were conducted on the mantle, gill, and digestive gland tissues of the mussels. Additionally, measurements of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), and lipid peroxidation levels were performed in the gill and digestive gland tissues. Oxidative responses were significantly elevated in both infection setups compared to the control group, with the directly injected samples exhibiting the highest oxidative responses (p < 0.05). Histological findings indicated that tissue-specific responses to host-pathogen interactions were consistent under both infection conditions. Notable observations included intense hemocytic infiltration in tissues, epithelial hyperplasia, and vacuolization in the gills, as well as focal necrotic areas in the digestive gland. The findings of this study indicate that V. mediterranei, a relatively novel pathogen, can provoke significant acute immune responses and tissue-level reactions in M. galloprovincialis, a species that is both widely distributed and vital to the food chain. These insights into the potential susceptibility of mussels underscore the need for further comprehensive research and inform the development of effective management strategies.

Evaluation of Antioxidant, Antibacterial, and Anti-hemolytic Properties of Ethanol Extract from Plectranthus barbatus Andrews (Lamiaceae) Leaves

Polyphenols can act as antioxidants, antibacterial, antifungal, or insecticidal agents. Given that microbial infections and arboviruses transmitted by Aedes aegypti significantly contribute to global morbidity and mortality, there is an urgent need to discover new antimicrobials and insecticides. This study investigated the ethanol extract (PbLE) of Plectranthus barbatus Andrews (Lamiaceae) leaves for its chemical constituents, antioxidant, antimicrobial, anti-hemolytic, and larvicidal activities. Qualitative analysis by Thin Layer Chromatography revealed cinnamic derivatives, flavonoids, terpenes, and steroids in PbLE. Quantitative analysis showed that PbLE contained 98.64 ± 0.87 mg EAG/g of total phenols, with flavonoids comprising 21.84 ± 0.34 mg EQ/g (c.a. 22%). PbLE demonstrated scavenging activity against ABTS+ (IC50 = 3246.00 ± 0.97 µg/mL) and DPPH (IC50 = 1371.75 ± 0.94 µg/mL) free radicals and exhibited reducing ability in the phosphomolybdenum method (IC50 = 899.33 ± 0.73 µg/mL). Although PbLE did not affect the growth or survival of pathogenic microorganisms, it significantly reduced (c.a. 80% for the extract at 256 mg/mL) the hemolysis caused by Staphylococcus aureus in human erythrocytes. Furthermore, PbLE (7 mg/mL) caused 40% mortality of A. aegypti third-instar larvae after 48-h exposure. In conclusion, PbLE, rich in phenolic compounds, acts as an antioxidant that mitigates S. aureus virulence to human erythrocytes and reduces the viability of A. aegypti larvae. The data reported herein contribute to the science by exploring P. barbatus, a medicinal plant with a long history of traditional use, as source of bioactive compounds with pharmacological and insecticidal properties. The determination of LC50 and mechanisms of PbLE larvicidal activity are underway.

An electron paramagnetic resonance time-course study of oxidative stress in the plasma of electronic cigarette exposed rats.

The long-term consequences of electronic cigarette (Ecig) use in humans are not yet known, but it is known that Ecig aerosols contain many toxic compounds of concern. We have recently shown that Ecig exposure impairs middle cerebral artery (MCA) endothelial function and that it takes 3days for MCA reactivity to return to normal. However, the sources contributing to impairment of the endothelium were not investigated. We hypothesized that the increased levels of oxidative stress markers in the blood are correlated with impaired MCA reactivity. We used electron paramagnetic resonance (EPR) spectroscopy to examine plasma from 4-month-old male Sprague-Dawley rats that were exposed to either air (n=5) or 1h Ecig exposure, after which blood samples were collected at varying times after exposure (i.e., 1-4, 24, 48 and 72h postexposure, n=4 or 5 in each time group). The EPR analyses were performed using the redox-sensitive hydroxylamine spin probe 1-hydroxy-3-carboxymethyl-2,2,5,5-tetramethyl-pyrrolidine (CMH) to measure the level of reactive oxidant species in the plasma samples. We found that EPR signal intensity from the CM• radical was significantly increased in plasma at 1-4, 24 and 48h (P<0.05, respectively) and returned to control (air) levels by 72h. When evaluating the EPR results with MCA reactivity, we found a significant negative correlation (Pearson's P=0.0027). These data indicate that impaired cerebrovascular reactivity resulting from vaping is associated with the oxidative stress level (measured by EPR from plasma) and indicate that a single 1h vaping session can negatively influence vascular health for up to 3 days after vaping. HIGHLIGHTS: What is the central question of this study? Does the time course of oxidative stress triggered by electronic cigarette exposure follow the cerebral vascular dysfunction? What is the main finding and its importance? Electron paramagnetic resonance analysis shows that the oxidative stress induced after a single 1h exposure to electronic cigarette aerosol takes ≤72h to return to normal, which mirrors the time course for vascular dysfunction in the middle cerebral artery that we have reported previously.

Physiological responses of the stingless bee Partamona helleri to oral exposure to three agrochemicals: impact on antioxidant enzymes and hemocyte count.

Agrochemicals pose significant threats to the survival of bees, yet the physiological impacts of sublethal doses on stingless bees remain poorly understood. This study investigated the effects of acute oral exposure to three commercial formulations of agrochemicals [CuSO4 (leaf fertilizer), glyphosate (herbicide), and spinosad (bioinsecticide)] on antioxidant enzymes, malondialdehyde content (MDA), nitric oxide (NO) levels, and total hemocyte count (THC) in the stingless bee Partamona helleri. Foragers were exposed to lethal concentrations aimed to kill 5% (LC5) of CuSO4 (120μgmL-1) or spinosad (0.85μgmL-1) over a 24-h period. Glyphosate-exposed bees received the recommended label concentration (7400μgmL-1), as they exhibited 100% survival after exposure. Ingestion of CuSO4 or glyphosate-treated diets by bees was reduced. Levels of NO and catalase (CAT) remained unaffected at 0h or 24h post-exposure. Superoxide dismutase (SOD) activity was higher at 0h compared to 24h, although insignificantly so when compared to the control. Exposure to CuSO4 reduced glutathione S-transferase (GST) activity at 0h but increased it after 24h, for both CuSO4 and glyphosate. MDA levels decreased after 0h exposure to CuSO4 or spinosad but increased after 24h exposure to all tested agrochemicals. THC showed no difference among glyphosate or spinosad compared to the control or across time. However, CuSO4 exposure significantly increased THC. These findings shed light on the physiological responses of stingless bees to agrochemicals, crucial for understanding their overall health.

Functional insights into the interaction of Lactobacillus spp. and potentially protective agents

The research addresses the critical need to explore how potentially protective agents (PPAs) influence the cellular characteristics of probiotic bacteria, with a focus on strain-specific responses. This study aimed to reveal the effect of 48-h exposure of the Lactobacillus spp. strains to selected PPAs on the viability, metabolic activity, stress response, surface properties, and physicochemical stability of bacterial suspensions. Results provide new insights into the potential risks or benefits of using the tested PPAs in probiotic production based on the analyzed strains, offering valuable information on their impacts on bacterial cells. Trehalose (TRE) and vitamin C (VC) notably impact the metabolic activity and surface characteristics of cells, with TRE improving viability and VC changing surface roughness and particle size distribution (PSD), suggesting a delicate balance between stress induction and viability enhancement. Inulin (IN) decreased metabolic changes, pointing the complex interplay between PPAs and bacterial metabolism. Results of zeta potential and PSD measurements revealed that other PPAs can either promote uniformity or induce aggregation of the bacterial suspensions. Findings have shown significant strain-specific effects of PPAs on bacterial viability and functionality, suggesting that their careful selection can improve bacterial health. Future directions include exploring the molecular mechanisms behind PPAs' effects and their practical applicability in real food systems.