Active Defense System Research Articles

Kolaviron via anti-inflammatory and redox regulatory mechanisms abates multi-walled carbon nanotubes-induced neurobehavioral deficits in rats.

Exposure to multi-walled carbon nanotubes (MWCNTs) reportedly elicits neurotoxic effects. Kolaviron is a phytochemical with several pharmacological effects namely anti-oxidant, anti-inflammatory, and anti-genotoxic activities. The present study evaluated the neuroprotective mechanism of kolaviron in rats intraperitoneally injected with MWCNTs alone at 1mg/kg body weight or orally co-administered with kolaviron at 50 and 100mg/kg body weight for 15 consecutive days. Following exposure, neurobehavioral analysis using video-tracking software during trial in a novel environment indicated that co-administration of both doses of kolaviron significantly (p < 0.05) enhanced the locomotor, motor, and exploratory activities namely total distance traveled, maximum speed, total time mobile, mobile episode, path efficiency, body rotation, absolute turn angle, and negative geotaxis when compared with rats exposed to MWCNTs alone. Further, kolaviron markedly abated the decrease in the acetylcholinesterase activity and antioxidant defense system as well as the increase in oxidative stress and inflammatory biomarkers induced by MWCNT exposure in the cerebrum, cerebellum, and mid-brain of rats. The amelioration of MWCNT-induced neuronal degeneration in the brain structures by kolaviron was verified by histological and morphometrical analyses. Taken together, kolaviron abated MWCNT-induced neurotoxicity via anti-inflammatory and redox regulatory mechanisms.

Neuroplasticity and Microglia Functions Applied in Dense Wireless Networks

This paper presents developments in the area of brain-inspired wireless communications relied upon in dense wireless networks. Classic approaches to network design are complemented, firstly, by the neuroplasticity feature enabling to add the learning ability to the network. Secondly, the microglia ability enabling to repair a network with damaged neurons is considered. When combined, these two functionalities guarantee a certain level of fault-tolerance and self-repair of the network. This work is inspired primarily by observations of extremely energy efficient functions of the brain, and of the role that microglia cells play in the active immune defense system. The concept is verified by computer simulations, where messages are transferred through a dense wireless network based on the assumption of minimized energy consumption. Simulation encompasses three different network topologies which show the impact that the location of microglia nodes and their quantity exerts on network performance. Based on the results achieved, some algorithm improvements and potential future work directions have been identified.

AB001. Keynote. Development of effective immune checkpoint cancer therapy

: My group also conducted a highly translational study, which identified a link between the ubiquitination and glycosylation pathways that regulate the immunosuppressive activity of programmed cell death-ligand 1 (PD-L1). We showed that glycosylation of PD-L1 is required for its protein stability and interaction with PD-1. In addition, we demonstrated that metformin-activated AMPK kinase downregulates PD-L1 through phosphorylation of Ser-195, which alters glycosylation of PD-L1 and functionally mimics anti-PD-L1 to block PD-L1/PD-1 interaction. It exhibited a highly potent synergistic effect of combination therapy of metformin, a drug that has been treated patients with diabetes and anti-CTLA4. The therapeutic efficacy could reach to survival rate of 50–70% in different syngeneic mouse models, which were treated by this combination therapy. We also demonstrated that epithelial-mesenchymal transition (EMT) enhancesPD-L1 in cancer stem-like cells (CSCs) by the EMT/β-catenin/STT3-PD-L1 signaling axis. Etoposide, a commonly used anti-cancer chemotherapy drug is able to suppress this signaling axis, resulting in downregulation of PD-L1 to sensitize cancer cells to anti-Tim 3 therapy. These findings provide potential therapeutic strategies to enhance cancer immune therapy efficacy by targeting PD-L1 stabilization to combat multiple cancer types. We identified TNF-α as a major factor triggering cancer cell immunosuppression against T cell surveillance via stabilization of PD-L1. To this end, in collaboration with StCube Pharmaceuticals Inc., we have developed monoclonal antibodies against glycosylation-specific PD-L1. Impressive therapeutic effect was observed through antibody-drug-conjugate approach. Most recently, we unraveled an active defense system of PD-L1, previously known to only associate with passive defense activity. We discovered that cancer cells, which express PD-L1 can secrete exosomes containing PD-L1 (exosome-PD-L1). The exosome-PD-L1 is able to directly interact with PD-1 to inhibit T-cell activation as well as T-cell killing activity. Our new discoveries provide new means to enhance therapeutic efficacy of immune checkpoint therapy.

Adaptively feature learning for effective power defense

Active defense technology is very important in intelligent systems and video surveillance. In some important fields, active defense system can effectively find intruders. Many intelligent video surveillance systems were proposed in recent years. They achieved good performance to some extent. Since power station is an important field, it is important to develop an intelligent video surveillance. Considering that detecting the whole surveillance video is time consumption and computation. So in this paper, we propose an active defense system to find intruders automatically. First, a key frame selection algorithm based on adaptive features is presented to select key frames. These key frames can cover the main content of videos and detecting these key frames can also reduce time consumption and computation. Then, a probabilistic model is proposed to learn the training data distribution. Finally, our system can achieve active defense based on probabilistic model. Experimental results show that our active defense system can achieve finding intruders effectively.

Accumulation, metabolite and active defence system responses of fluoxetine in zebrafish embryos: Influence of multiwalled carbon nanotubes with different functional groups

Studies on the bioavailability of organic contaminants adsorbed to nanomaterials are increasing. In this study, we investigated the interaction between fluoxetine (FLX) and three multiwalled carbon nanotubes (MWCNTs) with different functional groups in zebrafish (Danio rerio) embryos, focusing on the FLX accumulation, the formation of the metabolite norfluoxetine (NFLX), and the active defence system responses. The accumulation of FLX in zebrafish was intensified by MWCNTs (46–99%), which simultaneously facilitated the formation of the metabolite NFLX by 23–167%. The consistent enhancement revealed that the absorbed FLX is bioavailable in zebrafish. Moreover, the coexisting MWCNTs further promoted the influences of FLX on the active defence system in zebrafish (e.g. antioxidant and metabolic function), eliciting the defence function. The influences of MWCNTs on the bioavailability of FLX in zebrafish could be ordered as OH-MWCNTs > COOH-MWCNTs > pristine MWCNTs. The release of FLX from MWCNTs in biofluids may partially contribute to these significant alterations. In particular, MWCNTs themselves may also modulate the bioavailability of FLX in zebrafish by downregulating the gene expression of membrane ATP-binding cassette transporter (abcb4). These findings demonstrated that MWCNTs increased the bioavailability of FLX in zebrafish, especially the functionalized MWCNTs. The production of metabolites may be a useful bio-endpoint to evaluate the bioavailability of adsorbed contaminants on nanomaterials.

Decoupling Yeast Cell Division and Stress Defense Implicates mRNA Repression in Translational Reallocation during Stress

Stress tolerance and rapid growth are often competing interests in cells. Upon severe environmental stress, many organisms activate defense systems concurrent with growth arrest. There has been debate as to whether aspects of the stress-activated transcriptome are regulated by stress or an indirect byproduct of reduced proliferation. For example, stressed Saccharomyces cerevisiae cells mount a common gene expression program called the environmental stress response (ESR) [1] comprised of ∼300 induced (iESR) transcripts involved in stress defense and ∼600 reduced (rESR) mRNAs encoding ribosomal proteins (RPs) and ribosome biogenesis factors (RiBi) important for division. Because ESR activation also correlates with reduced growth rate in nutrient-restricted chemostats and prolonged G1 in slow-growing mutants, an alternate proposal is that the ESR is simply a consequence of reduced division [2-5]. A major challenge is that past studies did not separate effects of division arrest and stress defense; thus, the true responsiveness of the ESR-and the purpose of stress-dependent rESR repression in particular-remains unclear. Here, we decoupled cell division from the stress response by following transcriptome, proteome, and polysome changes in arrested cells responding to acute stress. We show that the ESR cannot be explained by changes in growth rate or cell-cycle phase during stress acclimation. Instead, failure to repress rESR transcripts reduces polysome association of induced transcripts, delaying production of their proteins. Our results suggest that stressed cells alleviate competition for translation factors by removing mRNAs and ribosomes from the translating pool, directing translational capacity toward induced transcripts to accelerate protein production.

Nitric oxide-mediated cross-talk of proline and heat shock proteins induce thermotolerance in Vicia faba L.

Due to the global warming, rising temperature became a serious threat to the world agriculture. Faba bean plant is very susceptible to heat stress and performs poorly under high temperature condition. Therefore, the performance of faba bean (Vicia faba L.), genotype ‘C5’ was tested to explore (i) the biosynthesis of proline (Pro) in response to heat stress (HS) and the involvement of nitric oxide (NO) and Pro in thermotolerance mechanism and (ii) the role of heat shock proteins (HSPs) and Pro in defense, and their correlation with the tolerance of faba bean plant to HS. Exposure of plants to HS for 48 h resulted in increased levels of reactive oxygen species [hydrogen peroxide (H2O2) and superoxide ions (O2•−)], nitric oxide (NO), accumulation of Pro and malondialdehyde, electrolyte leakage, DNA damage, chlorophyll (Chl) degradation and in decreased leaf relative water content (RWC) and Chl content in faba bean plants. However, at the same time increasing levels of HS (32, 37 and 42 °C) increased the accumulation of NO, Pro, activities of Pro metabolizing enzymes (Δ1-pyrroline-5-carboxylate synthetase, ornithine-δ-aminotransferase and proline dehydrogenase) and expression of HSPs (Hsp17.6, Hsp70, Hsp90-1, and Hsp101). Induced biosynthesis of NO and Pro under HS activated defense system of plants by enhancing the activities of antioxidant enzymes [superoxide dismutase, catalase, glutathione reductase and ascorbate peroxidase] and also by increasing the content of reduced glutathione (GSH), ascorbate (AsA) and oxidized glutathione (GSSG). While, an increase in GSSG content was found lesser than an increase in GSH under HS stress. Application of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO; an NO scavenger) decreased the accumulation of leaf RWC and Pro and NO. Therefore, it can be proposed that NO acts as both signal molecule and promotor of Pro biosynthesis. The present investigation reveals that above studied parameters could be used in identifying a HS-tolerant plant that can be utilized in future breeding programs.

Extended analysis of the Trojan-horse attack in quantum key distribution

The discrete-variable QKD protocols based on BB84 are known to be secure against an eavesdropper, Eve, intercepting the flying qubits and performing any quantum operation on them. However, these protocols may still be vulnerable to side-channel attacks. We investigate the Trojan-Horse side-channel attack where Eve sends her own state into Alice's apparatus and measures the reflected state to estimate the key. We prove that the separable coherent state is optimal for Eve amongst the class of multi-mode Gaussian attack states. We describe how Alice may defend against this by adding thermal noise to the system and give an analytic expression of the resulting secret key rate. We also provide a bound on the secret key rate in the case where Eve may use any separable state, and describe an active defense system based on optical modulators.

Active Defense Technology of Power Monitoring System With Adaptive Features

Internet of Things has found a lot of applications in power systems. However, with the increased the sensing, networking, and control capabilities, the security issues have become even more urgent at the same time. In this paper, a TMAC model based on trusted mandatory access control is proposed by studying the security situation of a power monitoring system. The model has self-learning characteristic and can realize the automatic escalation of the global security strategy based on intelligent agent, so as to build the safe immune ability and active defense system for the power monitoring. This paper introduces the key technology of the TMAC security model, formalizes some of the work, and finally tests its credibility and effectiveness for the typical application scenario of the power monitoring system. Through the study of this technology, the power monitoring system is further equipped with an immune ability against virus Trojan and hacker attacks, especially for application scenarios, such as substation, power plant, and master station.

Isolates of Lactobacillus plantarum and L. reuteri display greater antiproliferative and antipathogenic activity than other Lactobacillus isolates.

Lactic acid bacteria (LAB) have been associated with many beneficial effects in human digestive physiology. The aim of this study was to evaluate such effect, including attachment, antiproliferation and anti-pathogenic/antibacterial/antimicrobial properties of LAB isolated from healthy humans. Thirteen isolates, obtained from fecal samples of healthy individuals, were identified by phenotypic and molecular methods. Human colon adenocarcinoma cell line HT-29 and the cell proliferation kit II (XTT) assay were used for examination of the Lactobacillus adherence and antiproliferative activity, respectively. In addition, the inhibitory effect of Lactobacillus isolates against pathogenic bacteria was examined. Out of 13 Lactobacillus isolates, 5 (38 %) isolates were non-adhesive, 4 (31 %) were adhesive and 4 (31 %) were strongly adhesive. Amongst the isolated lactobacilli, L. reuteri showed the highest degree of inhibitory effect against the attachment of the enteropathogens. The XTT assay showed that 3 different isolates had the strongest antiproliferative activity with the maximum effect observed by L. plantarum isolates. Our results described that different Lactobacillus species isolated from normal fecal samples had different degrees of antiproliferative and anti-pathogenic/antibacterial/antimicrobial activities. However, no isolates showed all of the examined properties concurrently, suggestive that a combination of Lactobacillus species is needed for an active biological defense system.

Multimode Adaptable Microwave Radar Sensor Based on Leaky-Wave Antennas

New research and recent developments in active defense systems represent a promising way to protect military vehicles by detecting and subsequently eliminating threatening missiles with appropriate active counter-measures. Operating these defense systems requires a number of sensors, usually microwave, which must, above all, identify and track the target while generating signals to determine the correct counter-measure reaction. This paper shows that such multifunction and multimode sensors can be designed and implemented using leaky-wave antennas (LWAs). Connected radar circuits often employ a wideband modulation, so an analysis of the influence of the LWAs used on such a modulation is also included. A multimode adaptable pseudonoise radar equipped with LWAs was tested using bullets and live, armed cumulative missiles. The results confirm the functionality of the solutions presented.

Enterohaemorrhagic Escherichia coli produces outer membrane vesicles as an active defence system against antimicrobial peptide LL-37.

Antimicrobial peptides (AMPs) are important components of the innate immune system. Enterohaemorrhagic Escherichia coli (EHEC), a food-borne pathogen causing serious diarrheal diseases, must overcome attack by AMPs. Here, we show that resistance of EHEC against human cathelicidin LL-37, a primary AMP, was enhanced by butyrate, which has been shown to act as a stimulant for the expression of virulence genes. The increase of resistance depended on the activation of the ompT gene, which encodes the outer membrane protease OmpT for LL-37. The expression of the ompT gene was enhanced through the activation system for virulence genes. The increase in ompT expression did not result in an increase in OmpT protease in bacteria but in enhancement of the production of OmpT-loaded outer membrane vesicles (OMVs), which primarily contributed to the increase in LL-37-resistance. Furthermore, a sublethal dosage of LL-37 stimulated the production of OMVs. Finally, we showed that OMVs produced by OmpT-positive strains protect the OmpT-negative strain, which is susceptible to LL-37 by itself more efficiently than OMVs from the ompT mutant. These results indicate that EHEC enhances the secretion of OmpT-loaded OMVs in coordination with the activation of virulence genes during infection and blocks bacterial cell attack by LL-37.

Impairments of cadmium on vitellogenin accumulation in the hepatopancreas of freshwater crab Sinopotamon henanense.

During ovary maturation of crabs, vitellogenin (Vg), a precursor molecule of vitellin (Vn) needed for embryogenesis, can be produced in large quantities in the hepatopancreas and then transported to the ovary by the hemolymph. In the present study, effects of Cd on Vg accumulation in the hepatopancreas and Vg transportation of the freshwater crab Sinopotamon henanense were investigated. We also studied the impacts of Cd on the mRNA expression of genes involved in energy metabolism, protein metabolism, and metallothionein (MT) and glutathione (GSH) synthesis. After Cd treatment, the Vg concentration and the Vg mRNA expression in the hepatopancreas were downregulated. Pearson's correlation coefficient showed that the Vg level in the hepatopancreas correlated positively with those of the ovary and hemolymph (correlation coefficients 0.844 and 0.749, respectively), suggesting that the Vg transport from the hepatopancreas to the ovary can be impaired by Cd. The levels of carbohydrate and protein in the hepatopancreas of Cd-exposed crabs were decreased, and an inhibited protein metabolism was also observed. Energy production related isocitrate dehydrogenase and cytochrome C oxidase mRNA expressions, and MT and GSH synthesis increased after 10days of Cd treatment and decreased after 20days. Cd also caused a time-dependent upregulation of malondialdehyde. Our findings showed that Cd decreased Vg accumulation in the hepatopancreas due to partially excessive energy consumption and an activated defense system in the hepatopancreas, suggesting a possible regulatory mechanism in S. henanense which is the competitive advantage of energy reserves in metabolic Cd stress responses over the high-energy flux during vitellogenesis to ensure a continuous supply of metabolic energy. Moreover, the damage of Vg accumulation in the hepatopancreas caused by Cd could lead to an insufficient accumulation of Vn in the ovary and cause a retardation of oocyte development.

지상 접근 표적 감지를 위한 초소형 K-대역 레이다 연구

This paper proposes a compact K-band radar applied to a miniature proximity fuze for the active defense system. In this terrestrial environment, it is not easy to detect approaching small targets because the clutter is scattered. In addition, it is difficult to miniaturize the radar for the small proximity fuze while improving the target accuracy of the radar in such environments. To solve these difficulties, this study presents system analysis and design, antenna design, and transceiver and signal processor design of the compact K-band radar. Some test results are presented and the results are analyzed, the validity of the proposed study is examined.

AMELIORATIVE EFFECT OF METHANOLIC EXTRACT OF AZADIRACHTA INDICA LEAF ON LEAD ACETATE‐INDUCED CARDIOTOXOCITY, NEPHROTOXICITY AND GENOTOXICITY IN MALE WISTAR RATS

The persistent existence of lead in the environment is associated with severe health issues due to its cumulative effect and its ability to affect virtually every organ in the body. Recent discoveries have attributed the tissue damaging and inflammatory effects of lead toxicity to oxidative stress. Natural antioxidants are now being employed in the alleviation of lead‐induced toxicity and oxidative stress as they have been observed to be effective with little or no side effects associated.This study is designed to investigate the ameliorative and antioxidative effects of Azadirachta indica on lead induced cardiotoxicity and nephrotoxicity. Cardiotoxicity and nephrotoxicity was established following oral administration of lead acetate (1mg/ml and 2mg/ml) for six weeks. However, rats were treated with 100mg/kg and 200mg/kg body weight of methanolic extract of Azadiracta indica (MEAI) after oral administration of lead acetate.Lead acetate administration led to a significant increase in heart rate, blood pressure and markers of oxidative stress in cardiac and renal tissues. Enzymic and non‐enzymic antioxidant defense systems were increased by lead acetate toxicity, there was however a persistent increase in glutathione‐S‐transferase (GST) activity. Renal nitric oxide (NO) content was significant reduced whereas cardiac NO content increased significantly. However, treatment of rats with 100mg/kg and 200mg/kg body weight of methanolic extract of Azadiracta indica (MEAI) after oral administration of lead acetate led to improvement in antioxidant defense systems, reduction in markers of oxidative stress, restoration of blood pressure and electrocardiographic (ECG) changes respectively. Lead acetate also precipitated genotoxicity which was significantly attenuated by MEAI. The pericardial inflammation and necrosis as well as the peritubular inflammation observed in the histology of the heart and kidney tissues. This architectural anarchy was ameliorated by MEAI.In conclusion, the results of this study show that Azadirachta indica ameliorated lead acetate‐induced cardiotoxicity and nephrotoxicity through free radical scavenging activity and antioxidant defense system. Furthermore, heart rate, systolic and diastolic pressure and other haemodynamic parameters were restored to near normal by MEAI. Hence, Azadirachta indica is a potential drug candidate against environmental pollutant such as lead acetate.

Catalase activity in healthy and inflamed pulp tissues of permanent teeth in young people.

To evaluate catalase (CAT, EC 1.11.1.6) activity in healthy and inflamed dental pulp of young patient's teeth and to investigate if an active defense system oxidizing agents is present as a response to bacterial invasion. Twenty young patients between 15 and 25 ages, who were diagnosed to be healthy, were the source of the pulp tissue. The situation of the dental pulps was evaluated using clinical and radiographic assessments. The patients were divided two groups from healthy, and inflamed pulp tissues were obtained; each participant provided one pulp tissue specimens. The specimens were collected during endodontic treatment or by longitudinally grooving and splitting the teeth (if extracted). Catalase activity was determined through spectrophotometric methods and an independent sample t-test assessed the significance of differences between the groups. There was statistically a difference between healthy pulp tissue and inflamed pulp tissue (P < 0.005, independent sample t-test). The catalase activity of healthy group was significantly lower than inflamed pulp groups. The present study has shown that a significant increase in catalase activity is determined in inflamed dental pulps, which is due to pulpitis in comparison to healthy dental pulp.

An Algorithm of Clustering by Density Peaks Using in Anomaly Detection

With the development of the networks, the security of computer networks is becoming more and more serious. The information openness, sharing and interconnection are three important characteristics of computer networks. However, the amounts of intruders and attackers have been grows with the popularization of computers. Therefore, the focus of network security is preventing systems from being invaded effectively. Intrusion detection as a key technology of network security active defense system is designed to distinguish normal behaviors and attack behaviors. Intrusion detection is divided into misuse detection and anomaly detection, and using clustering algorithm is one of the most effective methods for anomaly detection. In this paper, a clustering algorithm based on fast search and find of density peaks is used to distinguish the normal and abnormal network connections to achieve the purpose of anomaly detection. The performance of the algorithm is tested by a data set selected from KDD CUP99. Experiment results show that this algorithm is more suitable than the traditional K-means in data sets containing a large amount of data and uneven density distribution.

Molecular Mechanism of the Two-Component Suicidal Weapon of Neocapritermes taracua Old Workers.

In termites, as in many social insects, some individuals specialize in colony defense, developing diverse weaponry. As workers of the termite Neocapritermes taracua (Termitidae: Termitinae) age, their efficiency to perform general tasks decreases, while they accumulate defensive secretions and increase their readiness to fight. This defensive mechanism involves self-sacrifice through body rupture during which an enzyme, stored as blue crystals in dorsal pouches, converts precursors produced by the labial glands into highly toxic compounds. Here, we identify both components of this activated defense system and describe the molecular basis responsible for the toxicity of N. taracua worker autothysis. The blue crystals are formed almost exclusively by a specific protein named BP76. By matching N. taracua transcriptome databases with amino acid sequences, we identified BP76 to be a laccase. Following autothysis, the series of hydroquinone precursors produced by labial glands get mixed with BP76, resulting in the conversion of relatively harmless hydroquinones into toxic benzoquinone analogues. Neocapritermes taracua workers therefore rely on a two-component activated defense system, consisting of two separately stored secretions that can react only after suicidal body rupture, which produces a sticky and toxic cocktail harmful to opponents.

Root Antioxidant Mechanisms in Relation to Root Thermotolerance in Perennial Grass Species Contrasting in Heat Tolerance.

Mechanisms of plant root tolerance to high temperatures through antioxidant defense are not well understood. The objective of this study was to investigate whether superior root thermotolerance of heat-tolerant Agrostis scabra relative to its congeneric heat-sensitive Agrostis stolonifera was associated with differential accumulation of reactive oxygen species and antioxidant scavenging systems. A. scabra ‘NTAS’ and A. stolonifera ‘Penncross’ plants were exposed to heat stress (35/30°C, day/night) in growth chambers for 24 d. Superoxide (O2 -) content increased in both A. stolonifera and A. scabra roots under heat stress but to a far lesser extent in A. scabra than in A. stolonifera. Hydrogen peroxide (H2O2) content increased significantly in A. stolonifera roots but not in A. scabra roots responding to heat stress. The content of antioxidant compounds (ascorbate and glutathione) did not differ between A. stolonifera and A. scabra under heat stress. Enzymatic activity of superoxide dismutase was less suppressed in A. scabra than that in A. stolonifera under heat stress, while peroxidase and catalase were more induced in A. scabra than in A. stolonifera. Similarly, their encoded transcript levels were either less suppressed, or more induced in A. scabra roots than those in A. stolonifera during heat stress. Roots of A. scabra exhibited greater alternative respiration rate and lower cytochrome respiration rate under heat stress, which was associated with suppression of O2 - and H2O2 production as shown by respiration inhibitors. Superior root thermotolerance of A. scabra was related to decreases in H2O2 and O2 - accumulation facilitated by active enzymatic antioxidant defense systems and the maintenance of alternative respiration, alleviating cellular damages by heat-induced oxidative stress.

Effect of Foliar Application with Methyl Jasmonate on Physiological Behavior of Mentha piperita

A valuable composition of Mentha piperita L. essential oil is menthol that is widely used fordifferent industries. The plants were treated with different concentrations of Methyl Jasmonate (MeJA) and after 24 h were evaluated for total soluble proteins, chlorophylls (a, b, and total), malondialdehyde, carbohydrates and antioxidant enzymes (Superoxide dismutase and Guaiacol peroxidase). Variance analysis indicated significant variation in all measured traits except for chlorophyll b that is caused by different concentration of MeJA. According to these results, MeJA could active antioxidant enzyme defense system. It can be concluded that stimulation of plant defense systems using elicitors could be a valuable and alternative strategy to protect Mentha piperita from stress.