Efficacy Of Defenses Research Articles

Comparative Investigation of Punica granatum L. Phytochemical Analysis and In-vitro Antimicrobial Activity Screening Using Roots Samples from Urban and Rural Areas Uses Five Different Solvent Extracts .

Antimicrobial, fungal, and bacterial infections in the human body are the causes of foodborne, waterborne, and airborne illnesses as well as those that arise naturally. Because nosocomial usage increases the presence of both complex and non-complicated microorganisms, urinary tract infections (UTIs) are most common, especially in women. Antibiotics are an amazing tool in the fight against infections; the WHO survey 2022(1) noted that microbial and fungal infections account for 1.5 billion deaths worldwide. The production of natural remedies is becoming a serious concern and is progressing quickly as well. Many phytochemical compounds from flora could be used to treat these infections based on the effect of the respective integrated organism’s host defense efficacy. The therapeutic or pathogen-resistant capacity of the phytochemicals under different chemical classes may reverse and control the antibiotic resistance of resistant pathogens. The aim of the study is to find the roots of Punica granatum L from the urban and rural regions to find the phytochemical efficacy from extracts like petroleum ether, chloroform, ethanol, carbinol and aqueous. It revealed that a high yield of pharmacological compounds is from a rural sample’s carbinol extract. Quantitative analysis showed the presence of high amounts of majorly anti-cancerous agents in high peaks from rural samples. Using the well diffusion method, in-vitro antimicrobial activity was determined. Against their negative controls, the inhibition activity of Escherichia coli showed a 22 mm inhibition zone from the ethanol extract, Staphylococcus aureus showed a 21 mm inhibition zone, and fungal pathogens such as Candida albicans and Candida krusei showed a 21 mm maximum inhibition zone from the carbinol extracts.

Palatability of ascidians: a meta-analysis of the predation effect on ascidians

Ascidians are marine sessile animals that have evolved many strategies to reduce predation. Previous manipulative experiments with ascidian tissues or pellets have shown that they have chemical defenses that render them unpalatable. However, predation-exclusion experiments on a community scale have shown that ascidians are almost entirely eaten when exposed to predators. Based on these contrasting results, we performed a meta-analysis to assess the importance of study site, experiment design, ascidian sociability, and predator identity to the efficacy of the ascidian defense. Our study is the first quantitative review of predation on ascidians, and it emphasizes the importance of ecological interactions beyond the specific defense tactics of the organisms. We found that multiple factors can interfere with the effectiveness of the ascidian defense. Palatability studies have shown evidence for ascidian defense mechanisms; however, they depend on the identity of the predators (e.g. fish, crab, amphipod). We did not find evidence of ascidian defense in community studies. There is a lack of field experiments, mainly on solitary ascidians, that evaluate their predation risk in communities. Research on ascidian defense mechanisms is also geographically biased toward the temperate region in the Northern Hemisphere. The commonly held belief that ascidians possess active defenses may be overestimated, and the defenses that do exist are probably restricted to only a few species. This misconception has been caused mainly by methodological and geographical bias that has resulted in tests being performed only on species with previous evidence of defenses. Therefore, we need more worldwide studies focusing on the ecological relationships between ascidians and predators, specifically in natural communities under field conditions.

Preparation and Application of Volatilized Wormwood Essence Derived Naturally into Green Insecticide.

Naturally occurring substances and their derivatives function as vital resources for pesticides that can be used in fields, such as insecticide production and fungicide development. As a botanical entity displaying multifaceted biological functions, wormwood has received thorough scrutiny across multiple sectors. The insect repellency potency combined with antibacterial and antifungal activities of wormwood position it as a potential candidate for prospective development into eco-friendly chemical pesticides. In this research, Wormwood essential oil was procured via ethanol water under ultrasonic scenarios and subsequently diluted with PEG 400 to formulate green chemical pesticides. The defensive efficacy of this green pesticide on plants was validated through 2 weeks of clustered plant growth experiments. Active constituents that exerted their effects were scrutinized by GC-MS. Furthermore, this green pesticide also displays efficacious effects on the prevention and management of aphids, exhibiting a dose-dependent relationship. 4-terpenol, eucalyptol, carvacrol, and L-borneol were identified by GC-MS as the predominant active constituents in this green chemical pesticide. Wormwood can be leveraged to develop green chemical pesticides, which can protect plants without contaminating the environment.

IL-33 controls IL-22-dependent antibacterial defense by modulating the microbiota

IL-22 plays a critical role in defending against mucosal infections, but how IL-22 production is regulated is incompletely understood. Here, we show that mice lacking IL-33 or its receptor ST2 (IL-1RL1) were more resistant to Streptococcus pneumoniae lung infection than wild-type animals and that single-nucleotide polymorphisms in IL33 and IL1RL1 were associated with pneumococcal pneumonia in humans. The effect of IL-33 on S. pneumoniae infection was mediated by negative regulation of IL-22 production in innate lymphoid cells (ILCs) but independent of ILC2s as well as IL-4 and IL-13 signaling. Moreover, IL-33's influence on IL-22-dependent antibacterial defense was dependent on housing conditions of the mice and mediated by IL-33's modulatory effect on the gut microbiota. Collectively, we provide insight into the bidirectional crosstalk between the innate immune system and the microbiota. We conclude that both genetic and environmental factors influence the gut microbiota, thereby impacting the efficacy of antibacterial immune defense and susceptibility to pneumonia.

Type I BREX system defends against antibiotic-resistant plasmids in Escherichia coli.

The Bacteriophage Exclusion (BREX) system is a novel antiphage defense system identified in Bacillus cereus in 2015. The purpose of this study was to investigate the presence of the BREX system defenses against antibiotic-resistant plasmids such as blaKPC and blaNDM invasion in Escherichia coli. The BREX system was present in 5.4% (23/424) of E. coli clinical isolates and 6.5% (84/1283) of E. coli strains with completely sequenced genomes in the GenBank database. All 23 BREX-positive E. coli clinical isolates were susceptible to carbapenems, while all five isolates carrying blaKPC and 11 carrying blaNDM were BREX-negative. For E. coli strains in the GenBank database, 37 of 38 strains carrying blaKPC and 109 of 111 strains carrying blaNDM were BREX negative. The recognition site sequence of methyltransferase PglX in a clinical E. coli 3756 was 5'-CANCATC-3' using PacBio single-molecular real-time sequencing. The transformation efficiency of plasmid psgRNA-ColAori-target with the PglX recognition site was reduced by 100% compared with the plasmid without the recognition site in E. coli DH5α-pHSG398-BREX. The BREX showed lower defense efficacy against plasmid psgRNA-15Aori-target which had the same plasmid backbone but different surrounding sequences of recognition sites with psgRNA-ColAori-target. The conjugation frequency of the KPC-2 plasmid and NDM-5 plasmid in E. coli 3756-ΔBREX was higher than that in E. coli 3756 clinical isolate (1.0 × 10-6 vs 1.3 × 10-7 and 5.5 × 10-7 vs 1.7 × 10-8, respectively). This study demonstrated that the type I BREX system defends against antibiotic-resistant plasmids in E. coli.

Immune interface interference vaccines: An evolution-informed approach to anti-bacterial vaccine design.

Developing protein-based vaccines against bacteria has proved much more challenging than producing similar immunisations against viruses. Currently, anti-bacterial vaccines are designed using methods based on reverse vaccinology. These identify broadly conserved, immunogenic proteins using a combination of genomic and high-throughput laboratory data. While this approach has successfully generated multiple rationally designed formulations that show promising immunogenicity in animal models, few have been licensed. The difficulty of inducing protective immunity in humans with such vaccines mirrors the ability of many bacteria to recolonise individuals despite recognition by natural polyvalent antibody repertoires. As bacteria express too many antigens to evade all adaptive immune responses through mutation, they must instead inhibit the efficacy of such host defences through expressing surface structures that interface with the immune system. Therefore, 'immune interface interference' (I3) vaccines that target these features should synergistically directly target bacteria and prevent them from inhibiting responses to other surface antigens. This approach may help us understand the efficacy of the two recently introduced immunisations against serotype B meningococci, which both target the Factor H-binding protein (fHbp) that inhibits complement deposition on the bacterial surface. Therefore, I3 vaccine designs may help overcome the current challenges of developing protein-based vaccines to prevent bacterial infections.

Diet influences resource allocation in chemical defence but not melanin synthesis in an aposematic moth.

For animals that synthesise their chemical compounds de novo, resources, particularly proteins, can influence investment in chemical defences and nitrogen-based wing colouration such as melanin. Competing for the same resources often leads to trade-offs in resource allocation. We manipulated protein availability in the larval diet of the wood tiger moth, Arctia plantaginis, to test how early life resource availability influences relevant life history traits, melanin production and chemical defences. We expected higher dietary protein to result in more effective chemical defences in adult moths and a higher amount of melanin in the wings. According to the resource allocation hypothesis, we also expected individuals with less melanin to have more resources to allocate to chemical defences. We found that protein-deprived moths had a slower larval development, and their chemical defences were less unpalatable for bird predators, but the expression of melanin in their wings did not differ from that of moths raised on a high-protein diet. The amount of melanin in the wings, however, unexpectedly correlated positively with chemical defences. Our findings demonstrate that the resources available in early life have an important role in the efficacy of chemical defences, but melanin-based warning colours are less sensitive to resource variability than other fitness-related traits.

Seed mucilage as a defense against granivory is influenced by substrate characters.

Many seeds are consumed by granivores despite numerous adaptations to prevent detection or exploitation. The environment can influence the efficacy of these defensive traits. Understanding the mechanisms by which environmental factors modify defensive efficacy is important for understanding spatial patterns of granivory and seed recruitment. Seed mucilage is a sticky coating that binds imbibed seeds to substrates; this attachment has been demonstrated to lessen exploitation by granivores. Seed mucilage as a defense has been recognized for decades, though rarely studied. Here, we investigated whether the environment alters this seed defense by addressing two questions: (1) Does substrate particle size affect attachment strength? (2) Does a change in particle size lead to changes in granivore-related mortality? In the field experiment, ants removed more seeds from finer substrates than their coarser counterparts. Across that same grit range, seeds took less force to dislodge when mucilage-bound to fine sandpaper; however, an investigation across a wider range of grits demonstrated nonlinearities occurred for many species, probably due to structural and chemical mucilage properties. Small differences in substrate grit lead to differential mortality in mucilaginous seeds due to alterations in attachment strength, suggesting that the defensive efficacy of this trait differs across the landscape. This work paves the way for a more integrative look at mucilaginous seeds. Seed mucilage is a widespread trait that is easily studied and has important demographic implications. It represents an ideal system to examine dispersal, germination, and granivory to gain a more holistic view of seed ecology.

Temperature alters the toxicological impacts of plant terpenoids on the polyphagous model herbivore Vanessa cardui

Terpenes are a major class of secondary metabolites present in all plants, and long hypothesized to have diversified in response to specific plant-herbivore interactions. Herbivory is a major biotic interaction that plays out across broad temporal and spatial scales that vary dramatically in temperature regimes, both due to climatic variation across geographic locations as well as the effect of seasonality. In addition, there is an emerging understanding that global climate change will continue to alter the temperature regimes of nearly every habitat on Earth over the coming centuries. Regardless of source, variation in temperature may influence herbivory, in particular via changes in the efficacy and impacts of plant defensive chemistry. This study aims to characterize temperature-driven variation in toxicological effects across several structural classes of terpenes in the model herbivore Vanessa cardui, the painted lady butterfly. We observed a general increase in monoterpene toxicity to larvae, pupa, and adults at higher temperatures, as well as an increase in development time as terpene concentration increased. Results obtained from this study yield insights into possible drivers of seasonal variation in plant terpene production as well as inform effects of rising global temperatures on plant-insect interactions. In the context of other known effects of climate change on plant-herbivore interactions like carbon fertilization and compensatory feeding, temperature-driven changes in plant chemical defense efficacy may further complicate the prediction of climate change impacts on the fundamental ecological process of herbivory.

Location-Aware Measurement for Cyber Mimic Defense: You Cannot Improve What You Cannot Measure

Cyber mimic defense is designed to ensure endogenous security, effectively countering unknown vulnerabilities and backdoors, thereby addressing a significant challenge in cyberspace. However, the immense scale of real-world networks and their intricate topology pose challenges for measuring the efficacy of cyber mimic defense. To capture and quantify defense performance within specific segments of these expansive networks, we embrace a partitioning approach that subdivides large networks into smaller regions. Metrics are then established within an objective space constructed on these smaller regions. This approach enables the establishment of several fine-grained metrics that offer a more nuanced measurement of cyber mimic defense deployed in complex networks. For example, the common-mode index is introduced to highlight shared vulnerabilities among diverse nodes, the transfer probability computes the likelihood of risk propagation among nodes, and the failure risk assesses the likelihood of cyber mimic defense technology failure within individual nodes or entire communities. Furthermore, we provide proof of the convergence of the transfer probability. A multitude of simulations are conducted to validate the reliability and applicability of the proposed metrics.

Not just the sum of its parts: Geographic variation and nonadditive effects of pyrazines in the chemical defence of an aposematic moth.

Chemical defences often vary within and between populations both in quantity and quality, which is puzzling if prey survival is dependent on the strength of the defence. We investigated the within- and between-population variability in chemical defence of the wood tiger moth (Arctia plantaginis). The major components of its defences, SBMP (2-sec-butyl-3-methoxypyrazine) and IBMP (2-isobutyl-3-methoxypyrazine), are volatiles that deter bird attacks. We hypothesized that (1) variation in the chemical defences of male wood tiger moths reflects the local predation pressure; (2) observed differences in quantity and quality of defence among populations have a genetic basis; and (3) increasing concentrations of SBMP and IBMP will elicit greater aversive reactions in predators, with the two pyrazines having an additive effect on predators' avoidance. We found that (1) the chemical defence of wild moths partly reflects local predator selection: high predation pressure populations (Scotland and Georgia) had stronger chemical defences, but not lower variance, than the low-predation populations (Estonia and Finland). (2) Based on the common garden results, both genetic and environmental components seem to influence the strength of chemical defence in moth populations; and (3) IBMP alone did not provide protection against bird predators but worked against bird attacks only when combined with SBMP, and while SBMP was more effective at higher concentrations, IBMP was not. Altogether this suggests that, when it comes to pyrazine concentration, more is not always better, highlighting the importance of testing the efficacy of chemical defence and its components with relevant predators, as extrapolating from chemical data may be less than straightforward.

Mode of action, chemistry and defensive efficacy of the osmeterium in the caterpillar Battus polydamas archidamas

Chemical secretions are one of the main defensive mechanisms in insects. The osmeterium is a unique organ in larvae of Papilionidae (Lepidoptera), which is everted upon disturbance, secreting odoriferous volatiles. Here, using larvae of the specialized butterfly Battus polydamas archidamas (Papilionidae: Troidini), we aimed to understand the mode of action of the osmeterium, the chemical composition and origin of the secretion, as well as its defensive efficiency against a natural predator. We described osmeterium’s morphology, ultramorphology, structure, ultrastructure, and chemistry. Additionally, behavioral assays of the osmeterial secretion against a predator were developed. We showed that the osmeterium is composed of tubular arms (made up by epidermal cells) and of two ellipsoid glands, which possess a secretory function. The eversion and retraction of the osmeterium are dependent on the internal pressure generated by the hemolymph, and by longitudinal muscles that connect the abdomen with the apex of the osmeterium. Germacrene A was the main compound present in the secretion. Minor monoterpenes (sabinene and ß-pinene) and sesquiterpenes ((E)-β-caryophyllene, selina-3,7(11)-diene, and other some unidentified compounds) were also detected. Only sesquiterpenes (with the exception of (E)-β-caryophyllene) are likely to be synthesized in the osmeterium-associated glands. Furthermore, the osmeterial secretion proved to deter predatory ants. Our results suggest that the osmeterium, besides serving as an aposematic warning for enemies, is an efficient chemical defense, with its own synthesis of irritant volatiles.

Assessing the Benefits and Costs of the Hydrogen Cyanide Antiherbivore Defense in Trifolium repens.

Understanding the evolution of plant defenses against herbivores requires identifying the benefits and costs of defense. Here, we tested the hypothesis that the benefits and costs of hydrogen cyanide (HCN) defense against herbivory on white clover (Trifolium repens) are temperature dependent. We first tested how temperature affected HCN production in vitro, and then examined how temperature influenced the efficacy of HCN defense of T. repens against a generalist slug (Deroceras reticulatum) herbivore using no-choice and choice feeding trial assays. To understand how temperature affected the costs of defense, plants were exposed to freezing, and HCN production, photosynthetic activity, and ATP concentration were quantified. HCN production increased linearly from 5 °C to 50 °C, and cyanogenic plants experienced reduced herbivory compared to acyanogenic plants only at warmer temperatures when fed upon by young slugs. Freezing temperatures induced cyanogenesis in T. repens and decreased chlorophyll fluorescence. Cyanogenic plants experienced lower ATP levels than acyanogenic plants due to freezing. Our study provides evidence that the benefits of HCN defense against herbivores are temperature dependent, and freezing may inhibit ATP production in cyanogenic plants, but the physiological performance of all plants recovered quickly following short-term freezing. These results contribute to understanding how varying environments alter the benefits and costs of defense in a model system for the study of plant chemical defenses against herbivores.

Evolution of match performance parameters in elite men's handball 2012–2022

The aim of this study was to quantify longitudinal changes in the games of the 6 Men’s European Handball Championship (EHC) celebrated between 2012 and 2022. A total of 563 match observations were examined. Specifically, the study contained the Number of Goals, Number of Attacks, Number of Shots, Number of Saves, Offensive Efficacy (Number of Goals/Number of Attacks × 100) and Defensive Efficacy (100 − Offensive Efficacy of the Opponent). Data were examined using the Kruskal–Wallis test and linear regression analysis. Results suggest that the number of goals remained relatively constant from 2012 to 2022. However, the number of attacks, shots, saves and defensive efficacy decreased, while offensive efficacy increased. These findings can contribute to a better understanding of how handball is evolving from a structural or tactical viewpoint.

Protective Effects of a Polyphenolic Phytochemical Quercetin against Oxidative Dysfunctions in Rats.

Quercetin hastraditionally been used in various oxidative and urinary tract dysfunctions. Thecurrent project is consequently set to evaluate the defensive efficacy ofQuercetin against potassium bromate (KBrO3) induced testiculartissue oxidative dysfunctions through biochemical, hormonal, and genotoxicmarkers. To observe theprotective efficacy of Quercetin against urinogenital oxidative dysfunction inrats, thirty six albino male rats were divided into six groups. Protectiveefficacies of Quercetin were checked on reproductive hormonal levels,antioxidant enzyme activities, lipids peroxidation (LP), and DNA damages. Potassium bromate exposure in experimentalanimals caused a reduction in the activities of antioxidant enzymes and disturbedhormonal secretions while enhancing the peroxidation of lipids andfragmentations of DNA. Cotreatment of Quercetin considerably (P<0.01)reversed these abnormalities with admiration to levels of hormones, antioxidantenzymes activities, and peroxidations of lipids secure to those seen inuntreated rats. (P < 0.01). The findings of the current project revealedthat various doses of Quercetin are able to keep the testicular organ fromabnormal free radical dysfunctions. These improvements might be due to theantioxidant ability of polyphenolic bioactive constituent, i.e., Quercetin.

The Hepatic Antioxidant Defense Efficacy of IDA Propolis in Aflatoxin B1 Administered Male Rats and Related Histopathological Findings

The Hepatic Antioxidant Defense Efficacy of IDA Propolis in Aflatoxin B1 Administered Male Rats and Related Histopathological Findings

User-Defined Privacy-Preserving Traffic Monitoring Against n-by-1 Jamming Attack

Traffic monitoring services collect traffic reports and respond to users’ traffic queries. However, the reports and queries may reveal the user’s identity and location. Although different anonymization techniques have been applied to protect user privacy, a new security threat arises, namely, n-by-1 jamming attack, in which an anonymous contributing driver impersonates <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> drivers and uploads <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> normal reports by using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> reporting devices. Such an attack will mislead the traffic monitoring service provider and further degrade the service quality. Existing traffic monitoring services do not support customized queries, and private information retrieval techniques cannot be applied directly in traffic monitoring. We formally define the new attack and propose a traffic monitoring scheme TraJ to defend the attack and achieve user-defined location privacy. Specifically, we bridge anonymous contributing drivers without disclosing their speed set by using private set intersection. Each RSU collects time traffic reports and structures a weighted proximity graph to filter out malicious colluding drivers. We design a user-defined privacy-preserving query method by encoding complex road network. We leverage the uploading phase from private aggregation to collect traffic conditions and allow requesting drivers to dynamically and privately query traffic conditions. We provide a formal analysis of TraJ to prove its privacy and security properties. We also construct a prototype based on a real-world dataset and Android smartphones to demonstrate its feasibility and efficiency. A formal analysis demonstrates the privacy and security properties. Extensive experiments illustrate the performance and defense efficacy.

Glutathione metabolism in Cryptocaryon irritans involved in defense against oxidative stress induced by zinc ions

BackgroundCryptocaryon irritans is a fatal parasite for marine teleosts and causes severe economic loss for aquaculture. Galvanized materials have shown efficacy in controlling this parasite infestation through the release of zinc ions to induce oxidative stress.MethodsIn this study, the resistance mechanism in C. irritans against oxidative stress induced by zinc ions was investigated. Untargeted metabolomics analysis was used to determine metabolic regulation in C. irritans in response to zinc ion treatment by the immersion of protomonts in ZnSO4 solution at a sublethal dose (20 μmol). Eight differential metabolites were selected to assess the efficacy of defense against zinc ion stimulation in protomonts of C. irritans. Furthermore, the mRNA relative levels of glutathione metabolism-associated enzymes were measured in protomonts following treatment with ZnSO4 solution at sublethal dose.ResultsThe results showed that zinc ion exposure disrupted amino acid metabolism, carbohydrate metabolism, lipid metabolism, and nucleotide metabolism in C. irritans. Four antioxidants, namely ascorbate, S-hexyl-glutathione, syringic acid, and ubiquinone-1, were significantly increased in the Zn group (P < 0.01), while the glutathione metabolism pathway was enhanced. The encystment rate of C. irritans was significantly higher in the ascorbate and methionine treatment (P < 0.05) groups. Additionally, at 24 h post-zinc ion exposure, the relative mRNA level of glutathione reductase (GR) was increased significantly (P < 0.01). On the contrary, the relative mRNA levels of glutathione S-transferase (GT) and phospholipid-hydroperoxide glutathione peroxidase (GPx) were significantly decreased (P < 0.05), thus indicating that the generation of reduced glutathione was enhanced.ConclusionsThese results revealed that glutathione metabolism in C. irritans contributes to oxidative stress resistance from zinc ions, and could be a potential drug target for controlling C. irritans infection.Graphical

Corner kick effectiveness in the Greek Super League 2018-2019

The aim of the present study was to describe how corner kicks were taken and to identify key variables associated with final attempts during Greek Super League season 2018-19. There was a total of 424 final attempts after corner kick, of which, 16.3% were attempts off target, 6.8% attempts on target and 2.8% resulting in a goal. Bivariate analysis presented that attempts on target were increased when the ball was delivered outswing, no players positioned at the goal posts, &gt;1 intervening attackers, attacking player the 1st contact and ball delivered into the central zones of the 18-yard box. Binary logistic regression (Final attempt/ No Final attempt) revealed that the model was statistically significant for the final attempt (p &lt; 0.001) and showed that the intervening attackers (p &lt; 0.001) and the player of the 1st contact (p &lt; 0.001) contributed significantly to the model. These results can aid coaches to enhance on one hand the attacking effectiveness; on the other hand the defensive efficacy of corner kicks within Greek football.

Effect of sublethal concentrations of the antiparasitic ivermectin on the polychaeta species Hediste diversicolor: biochemical and behavioral responses.

Pharmaceutical drugs have emerged as major micropollutants in aquatic ecosystems. Their presence has been systematically reported in monitoring surveys, and their wide distribution and constant presence in the wild is a direct consequence of their massive use, in both human and veterinary therapeutics. Drugs used to treat parasitic infections in livestock are major contaminants, given the amounts in which they are administered, and reach the aquatic compartment in high amounts, where they may affect non target species. Some of these drugs are prone to find their final deposit in sediments of estuarine areas, exerting their toxic effects preferentially at these locations. Sediment dwelling organisms of coastal areas, such as polychaetas, are especially prone to have their major physiological functions compromised after being exposed to pharmaceutical drugs. Ivermectin is one of the most used antiparasitic drugs, and its effects are not limited to biochemical traits, but also behavioral features may be compromised considering their neurotoxic actions. Despite these putative effects, little is known about their toxicity on polychaetas. The present study aimed to characterize the toxicity of realistic levels of ivermectin on the polychaeta Hediste diversicolor, in biochemical and behavioral terms. The obtained results showed that low levels of ivermectin are capable of causing significant disturbances in mobility and burrowing activity of exposed worms, as well as alterations of metabolic and anti-oxidant defense efficacy of exposed animals, suggesting that its environmental presence may mean a major environmental concern.