ROS

We present a study on whether and to what extent subcellular localization may compete favorably with photosensitization efficiency with respect to the overall efficiency of photoinduced cell death. We have compared the efficiency with which two cationic photosensitizers, namely methylene blue (MB) and crystal violet (CV), induce the photoinduced death of human cervical adenocarcinoma (HeLa) cells. Whereas MB is well known to generate singlet oxygen and related triplet excited species with high quantum yields in a variety of biological and chemical environments (i.e., acting as a typical type II photosensitizer), the highly mitochondria-specific CV produces triplet species and singlet oxygen with low yields, acting mostly via the classical type I mechanism (e.g., via free radicals). The findings described here indicate that the presumably more phototoxic type II photosensitizer (MB) does not lead to higher degrees of cell death compared to the type I (CV) photosensitizer. In fact, CV kills cells with the same efficiency as MB, generating at least 10 times fewer photoinduced reactive species. Therefore, subcellular localization is indeed more important than photochemical reactivity in terms of overall cell killing, with mitochondrial localization representing a highly desirable property for the development of more specific/efficient photosensitizers for photodynamic therapy applications.

Recently, research on the biological effects of nanoplastics has grown exponentially. However, studies on the effects of nanoplastics on freshwater organisms and the mechanisms of the biological effects of nanoplastics are limited. In this study, the content of reactive oxygen species (ROS), gene and protein expression in the MAPK-HIF-1/NFkB pathway, and antioxidant gene expressions and enzyme activities were measured in Daphnia pulex exposed to polystyrene nanoplastic. In addition, the full-length extracellular signal-regulated kinases (ERK) gene, which plays an important role in the MAPK pathway, was cloned in D. pulex, and the amino acid sequence, function domain, and phylogenetic tree were analyzed. The results show that nanoplastic caused the overproduction of ROS along with other dose-dependent effects. Low nanoplastic concentrations (0.1 and/or 0.5 mg/ L) significantly increased the expressions of genes of the MAPK pathway (ERK; p38 mitogen-activated protein kinases, p38; c-Jun amino-terminal kinases, JNK; and protein kinase B, AKT), HIF-1 pathway (prolyl hydroxylasedomain, PHD; vascular endothelial growth factor, VEGF; glucose transporter, GLUT; pyruvate kinase M, PKM; hypoxia-inducible factor 1, HIF1), and CuZn superoxide dismutase (SOD) along with the activity of glutathione-S-transferase. As the nanoplastic concentration increased, these indicators were significantly suppressed. The protein expression ratio of ERK, JNK, AKT, HIF1α, and NFkBp65 (nuclear transcription factor-kB p65) as well as the phosphorylation of ERK and NFkBp65 were increased in a dose-dependent manner. The activities of other antioxidant enzymes (catalase, total SOD, and CuZn SOD) were significantly decreased upon exposure to nanoplastic. Combined with our previous work, these results suggest that polystyrene nanoplastic causes the overproduction of ROS and activates the downstream pathway, resulting in inhibited growth, development, and reproduction. The present study fosters a better understanding of the biological effects of nanoplastics on zooplankton.

Over the horizon of automation and robotics, the designing of an economically efficient robot with multiple features via an open source tool becomes immensely important and greatly valid. Though substantially demandable Computer Numerical Control (CNC) programming constituting g code and m code for controlling , starting, stopping of robots is used as a procedural instruction for 3D printing it lacks in the domain of feedback control. An open source moveo which is an open design is being stimulated. Here , It is made to perform as a powerful equipment reconnoitering multiplex actions. Initially beginning with the construction of the robotic arm, the proposed idea deals with stimulating, controlling the real robot and the interface between these two. Simulation of the robot involves the creation of URDF file of the moveo using solidworks. Controlling deals with the coupling of Arduino Mega 2560 along with a RAMPS 1.4 and the stepper motors. And finally, the main objective that is the interface between these two modules such that the real robot echoing the movements or changes made in the stimulation part is achieved with the creation of rosnode that converts the rotation into steps necessary to move the robotic arm as desired. Systamizing of objects in automation industries could be consummated by this trajectory.

The mechatronic systems represent one of the most challenging control applications due to their interdisciplinary nature. Numerous control algorithms have been proposed to deal with nonlinear dynamics of the mechatronic systems. For linear mechatronic systems, the proportional-integral-derivative (PID) controller is often used owing to its simple structure and robustness. One of the most common applications in all mechatronic domains is the control of DC motors. To develop a product which will can be used efficiently. In this case, develop a PCB (Printed Circuit Board) to control a servomotor position and speed. Arduino UNO ATMEGA 328 is used to control the motor. This motor is controlled using PID logic (Proportional Integrative Differential). The PID logic is implemented in the motor using the Arduino UNO ATMEGA 328 micro controller. After implementing the above, proteus design is made and PCB is printed. The final printed circuit board will be able to control the motor using PID logic.

A robot end-mounted camera is used to position the robot arm in a plane orthogonal to the axis, such that the fruit to be harvested is centered in the camera’s field of view. The system has no trajectory generator, instead a feedback loop, closed visually, is used to control the robots arm position. (Two control laws were simulated: join angles and joint velocity)

El síndrome de Guillain-Barré es un trastorno neurológico donde el sistema inmune del cuerpo ataca
al sistema nervioso periférico. Esta enfermedad es
de rápida evolución y es la causa más frecuente de
parálisis del cuerpo. Existen cuatro variantes de SGB:
polineuropatía desmielinizante inflamatoria aguda,
neuropatía axonal motora aguda, neuropatía axonal
sensorial aguda y síndrome de Miller-Fisher. Identificar el subtipo de SGB que el paciente contrajo es
determinante debido a que el tratamiento es diferente
para cada subtipo. El objetivo de este estudio fue
determinar cuál algoritmo de sobremuestreo mejora
el rendimiento de los clasificadores. Además, determinar si balancear los datos mejoran el rendimiento de
los modelos predictivos. Aplicamos tres métodos de
sobremuestro (ROS, SMOTE y ADASYN) a la clase
minoritaria, utilizamos tres clasificadores (C4.5, SVM
y JRip). El rendimiento de los modelos se obtuvo mediante la curva ROC. Los resultados muestran que
balancear el dataset mejora el rendimiento de los modelos predictivos. El algoritmo SMOTE fue el mejor
método de balanceo en combinación con el clasificador
JRip para OVO y el clasificador C4.5 para OVA.

Streszczenie: Utrzymanie homeostazy w komórkach żywych organizmów eukariotycznych zależy od ilości oraz aktywności wielu różnych białek, które są regulowane na poziomie transkrypcji, translacji, modyfikacji potranslacyjnych, a także od efektywności ich proteolizy. Istotną rolę w degradacji specy-ficznych białek uczestniczących w regulacji wielu procesów życiowych roślin, odgrywają katalityczne kompleksy proteaz, zwane proteasomami 26S i 20S. Proteoliza z udziałem tego pierwszego, wymaga zaangażowania różnego rodzaju enzymów, tworzących wspólnie szlak ubikwitynowo-proteasomal-ny (ang. Ubiquitin-Proteasome Pathway, UPP). Białka enzymatyczne uczestniczące w UPP odpowi-adają za rozpoznawanie protein przeznaczonych do degradacji oraz przyłączanie do nich cząsteczek ubikwityny (peptyd złożony z 76 reszt aminokwasowych, Ub), umożliwiając tym samym ich prote-olizę. Natomiast, rozkład białek przez 20S jest ubikwitynowo niezależny. Na drodze proteasomalnej usuwane są białka uszkodzone, ale również te o właściwej budowie, jak np.: enzymy szlaków bio-syntetycznych regulujące funkcjonowanie komórek, białka modulujące przebieg cyklu komórkowe-go, czynniki transkrypcyjne, itp. W niniejszej pracy omówiono najnowsze odkrycia dotyczące roli i mechanizmu działania proteasomów w biologii nasion. Podano przykłady wybranych, niedawno poznanych, białkowych elementów hormonalnych szlaków sygnałowych, które ulegają degradacji proteasomalnej i pełnią istotne funkcje w biologii nasion. Zaprezentowano dowody potwierdzające, iż wśród specyficznych białek rozkładanych przez proteasom 26S, o istotnym znaczeniu w biologii nasion, występują między innymi: czynniki transkrypcyjne regulujące odpowiedź na kwas abscysyn-owy (ABA), takie jak ABI; białka DELLA biorące udział w regulacji sygnału indukowanego przez gibereliny (GA); a także czynniki regulatorowe Aux/IAA uczestniczące w szlaku sygnałowym auksyn (IAA) oraz wiele innych. Ponadto, przedstawiono prekursorskie wyniki badań wskazujące, iż mecha-nizm regulacji procesów przebiegających w nasionach, jest również związany ze zmianami w metab-olizmie reaktywnych form tlenu (ang. Reactive Oxygen Species, ROS) oraz degradacją specyficznych, karbonylowanych białek przez kompleks 20S. Dane zawarte w tej pracy przeglądowej podkreślają rolę proteasomów, jako kluczowych elementów wpływających na zależne od sygnałów hormonalnych i ROS procesy zachodzące w nasionach. Słowa kluczowe: hormony roślinne, kiełkowanie, nasiona, proteasomalna degradacja białek, reakty-wne formy tlenu

<p>(A) The initial oxidative DNA damage was measured in monocytes and macrophages using an FPG-modified alkaline Comet assay. Cells were treated with PMA for 15 min and then incubated for additional 45 min in PMA free medium. Monocytes and macrophages showed similar levels of initial DNA damage. (B) In parallel, 8OHdG was detected via immunostaining. Both monocytes and macrophages displayed clear 8OHdG staining after PMA treatment compared to the solvent control. (C) DNA strand breaks were measured at different times after the ROS burst was induced by 15 min PMA treatment. Monocytes displayed increasing levels of strand breaks over time compared to macrophages. (D) Monocytes and macrophages were treated with PMA for 15 min and cell death was measured 48 h later. Monocytes displayed increased apoptosis compared to macrophages, which were resistant. Control, untreated cells; solvent, DMSO control (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0170347#sec002" target="_blank">material and methods</a>). Data are the mean of at least three independent experiments ± SEM, 1-way ANOVA, Tukey’s Multiple Comparison Test, **p < 0.01, ***p < 0.001.</p

Quercetin is a bioactive compound with anti-inflammatory, antioxidant and anticancer properties. This study exemplifies the differential cytotoxic activity of Quercetin on two human colonic cancer cell lines, HT29 and HCT15. IC 50 of Quercetin for HT29 and HCT15 cells were 42.5 mM and 77.4 mM, respectively. Activation of caspase-3, increased level of cytosolic cytochrome c, decreased levels of pAkt, pGSK-3b and cyclin D1 in 40 mM Quercetin treated HT29 cells alone. Though, nuclear translocation of NFkB was increased in 40 mM Quercetin treated HT29 and HCT15 cells, over expression of COX-2 was observed in 40 mM Quercetin treated HT29 cells, whereas, Quercetin treated HCT15 cells did not expressed COX-2. Increased generation of reactive oxygen species (ROS) was observed only in Quercetin treated HT29 cells, which is due to over expression of COX-2, as COX-2 silencing inhibited Quercetin induced apoptosis and ROS generation. Insilico analysis provided evidence that Quercetin could partially inhibit COX-2 enzyme by binding to subunit A which has peroxidase activity and serves as source of ROS. However, Quercetin showed minimal effect on normal intestinal epithelial cells i,e IEC-6. To conclude, differential sensitivity of two cancer cells, HT29 and HCT15, to Quercetin depends on COX-2 dependent ROS generation that induces apoptosis and inhibits cell survival.

The sessile nature of plants has resulted in the evolution of an extraordinarily diverse suite of protective mechanisms against biotic and abiotic stresses. Though volatile isoprenoids are known to be involved in many types of biotic interactions, they also play important but relatively unappreciated roles in abiotic stress responses. We review those roles, discuss the proposed mechanistic explanations and examine the evolutionary significance of volatile isoprenoid emission. We note that abiotic stress responses generically involve production of reactive oxygen species in plant cells, and volatile isoprenoids mitigate the effects of oxidative stress by mediating the oxidative status of the plant. On the basis of these observations, we propose a 'single biochemical mechanism for multiple physiological stressors' model, whereby the protective effect against abiotic stress is exerted through direct or indirect improvement in resistance to damage by reactive oxygen species

Under abiotic stress conditions, arbuscular mycorrhizal (AM) fungi help plants by improving nutrient and water uptake. Finger millet (Eleusine coracana L.) is an arid crop having soils with poor water holding capacity. Therefore, it is difficult for the plants to obtain water and mineral nutrients from such soil to sustain life. To understand the role of mycorrhizal symbiosis in water and mineral up-take from the soil, we studied the role of Rhizophagus intraradices colonization and its beneficial role for drought stress tolerance in finger millet seedlings. Under severe drought stress condition, AM inoculation led to the significant increase in plant growth (7 %), phosphorus and chlorophyll content (29 %). Also, under drought stress the level of osmolytes such as proline and soluble sugars were found to be increased in AM inoculated seedlings. Under water stress, the lipid peroxidation in leaves of mycorrhized seedlings was reduced by 29 %. The flavonoid content of roots in AM colo...

Cells are sensitive to a variety of signals in their environment, which they respond to and integrate. Signal transduction at the cellular level refers to the movement of signals from outside the cell to inside. A "cross-talk", between heterologous cell signaling systems gives a complex communication of molecules in various tissues a new dimension and specifies the type of the obtained biological response. A biochemical basis for transducing extracellular signals into an intracellular event has long been the subject of enormous interest. The mechanisms underlying ROS-mediated signal transduction in oxidative stress response involve a direct alteration in transcription factors and kinases and indirect modulation of cysteine-rich redox-sensitive signaling proteins. In a given signaling protein, oxidative attack induces either a loss of function, a gain of function, or a switch to a different function. Identifying the target proteins for redox modification is the key to under...

Cardiac biomarkers are important targets for any test sample to discover ideal cardiac health supplement. The study was aimed to evaluate the cardioprotective activity of Biofield Energy Treated test sample (DMEM) using rat cardiomyocytes (H9c2) cells. The test item (DMEM medium) was divided into three parts, first part received one-time Biofield Treatment by Alice Branton, a renowned Biofield Energy Healer, and defined as the one-time Biofield Energy Treated (BT-I) DMEM, while second part received two-times Biofield Energy Treatment and denoted as the BT-II DMEM. The third part did not give treatment and denoted as the untreated DMEM group. The cell viability of the test sample by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay showed an increase level of viable cells by 86.58% and 91.37% in the BT-I and BT-II groups, respectively. Besides, BT-I and BT-II groups showed 10.56% and 23.53% cytoprotective action compared to the tert-Butyl hydroperoxide (t-BHP) induced group. Further, lactate dehydrogenase (LDH) level was significantly (p≤0.001) reduced by 54.43% and 53.52% in the BT-I and BT-II groups, respectively compared to t-BHP induced group. Moreover, the level of creatine kinase-myocardial band (CK-MB) was reduced by 63.48% and 60.68% in the BT-I and BT-II groups, respectively compared to the t-BHP induced group. Additionally, reactive oxygen species (ROS) level was significantly inhibited by 55.6% and 112.8% in the BT-I and BT-II groups, respectively compared to the t-BHP induced group. Besides, apoptotic activity was significantly inhibited by 16% and 10% in the BT-I and BT-II groups, respectively compared to the t-BHP induced group. Overall, the experimental data demonstrated that The Trivedi Effect® has significant capacity to improve the overall cardiac parameters in H9c2 cells, which can be used against various cardiac disorders such as congestive heart failure (CHF), cardiomyopathy, heart valve disorders, arrhythmias, myocardial infarction, etc.

Malignant mesothelioma (MMe) is a highly aggressive, lethal tumor requiring the development of more effective therapies. The green tea polyphenol epigallocathechin-3-gallate (EGCG) inhibits the growth of many types of cancer cells. We found that EGCG is selectively cytotoxic to MMe cells with respect to normal mesothelial cells. MMe cell viability was inhibited by predominant induction of apoptosis at lower doses and necrosis at higher doses. EGCG elicited H(2) O(2) release in cell cultures, and exogenous catalase (CAT) abrogated EGCG-induced cytotoxicity, apoptosis and necrosis. Confocal imaging of fluo 3-loaded, EGCG-exposed MMe cells showed significant [Ca(2+) ](i) rise, prevented by CAT, dithiothreitol or the T-type Ca(2+) channel blockers mibefradil and NiCl(2) . Cell loading with dihydrorhodamine 123 revealed EGCG-induced ROS production, prevented by CAT, mibefradil, or the Ca(2+) chelator BAPTA-AM. Direct exposure of cells to H(2) O(2) produced similar effects on Ca(2+) and ROS, and these effects were prevented by the same inhibitors. Sensitivity of REN cells to EGCG was correlated with higher expression of Ca(v) 3.2 T-type Ca(2+) channels in these cells, compared to normal mesothelium. Also, Ca(v) 3.2 siRNA on MMe cells reduced in vitro EGCG cytotoxicity and abated apoptosis and necrosis. Intriguingly, Ca(v) 3.2 expression was observed in malignant pleural mesothelioma biopsies from patients, but not in normal pleura. In conclusion, data showed the expression of T-type Ca(2+) channels in MMe tissue and their role in EGCG selective cytotoxicity to MMe cells, suggesting the possible use of these channels as a novel MMe pharmacological target

En este proyecto se pretende modelar, simular y construir un robot cuadrúpedo basado en la plataforma open source Spot Micro (robot inspirado en Spot mini de Boston Dynamics). El objetivo es mediante el estudio de los distintos sistemas actualmente disponibles, desarrollar una plataforma robótica de bajo coste multipropósito, por fases de desarrollo. Se explorará el sistema actual, se corregirán los defectos y finalmente se mejorará dotándolo con la posibilidad de alcanzar cierto nivel de autonomía. Se pretende también generar un programa de gestión que permita el control de sus articulaciones y de los distintos sensores incorporados así como establecer las bases para el entrenamiento de un agente con aprendizaje por refuerzo que sirva como futuro controlador del robot vía teleoperación o control manual

We previously described the behaviour of different cobalt forms, i.e., cobalt nanoparticles (CoNP), cobalt microparticles (CoMP) and cobalt ions (Co(2+)), in culture medium (dissolution, interaction with medium components, bioavailability) as well as their uptake and intracellular distribution in Balb/3T3 mouse fibroblasts (Sabbioni, Nanotoxicology, 2012). Here, we assess the cytotoxicity and morphological transformation of CoNP compared not only to Co(2+), but also to CoMP and to released Co products. Cytotoxicity reached maximum at 4-h exposure, with ranking CoMP > CoNP > Co(2+). However, if we consider toxicity as a function of intracellular Co, toxicity of the ionic forms seems to prevail over the particles. Co forms other than Co(2+) released from particles had toxicity intermediate between particles and ions. Alterations in concentrations of essential elements (Cu, Mg, Zn) in cells exposed to Co particles may contribute to toxicity. Both CoMP and CoNP (but not Co(2+) and other released Co forms) induced morphological transformation (CoMP > CoNP). This was dependent on reactive oxygen species production and lipid peroxidation, as indicated by inhibition of type III foci with ascorbic acid. The present results suggest that the previously demonstrated massive mitochondrial and nuclear Co internalisation and DNA adduct formation by CoMP and CoNP (Sabbioni, Nanotoxicology, 2012) induce toxicity and transformation. On the contrary, the role of ions released by particles in culture medium is negligible. Thus, both the chemical and the physical properties of Co particles contribute to cytotoxicity and morphological transformation.

Abstract. Previous reports have demonstrated that increased levels of reactive oxygen species (ROS) and alterations in cell signaling characterize aging in the Fischer 344 X Brown Norway (FBN) rat aorta. Other work has suggested that increases in ROS may be related to vascular wall thickening and the development of hypertension. Paracetamol (acetaminophen) is a potent antioxidant that has been found to diminish free radicals in ischemia-reperfusion studies. However, it remains unclear whether chronic paracetamol administration influences signaling or ROS accumulation in the aging aorta. FBN rats (27 months old; n=8) were subjected to 6 months of treatment with a therapeutic dose of paracetamol (30 mg/kg/day) and compared to age-matched untreated FBN rat controls (n=8). Compared to measurements in the aortae of 6-month old animals, tunica media thickness, tissue superoxide levels, and protein oxidation levels were 38 ± 7%, 92 ± 31%, and 7 ± 2 % higher in the aortae of 33-month contro...

In clinical practice, patients with anaplastic lymphoma kinase (ALK)-rearrangement–positive non–small-cell lung cancer commonly receive sequential treatment with ALK tyrosine kinase inhibitors. The third-generation agent lorlatinib has been shown to inhibit a wide range of ALK resistance mutations and thus offers potential benefit in later lines, although real-world data are lacking. This multicenter study retrospectively investigated later-line, real-world use of lorlatinib in patients with advanced ALK- or ROS1-positive lung cancer. Fifty-one patients registered in a compassionate use program in Austria, who received second- or later-line lorlatinib between January 2016 and May 2020, were included in this retrospective real-world data analysis. Median follow-up was 25.3 months. Median time of lorlatinib treatment was 4.4 months for ALK-positive and 12.2 months for ROS-positive patients. ALK-positive patients showed a response rate of 43.2%, while 85.7% percent of the ROS1-positive...

Consequences of drought stress in crop production systems are perhaps more deleterious than other abiotic stresses under changing climatic scenarios. Regulations of physio-biochemical responses of plants under drought stress can be used as markers for drought stress tolerance in selection and breeding. The present study was conducted to appraise the performance of three different maize hybrids (Dong Dan 80, Wan Dan 13, and Run Nong 35) under well-watered, low, moderate and SD conditions maintained at 100, 80, 60, and 40% of field capacity, respectively. Compared with well-watered conditions, drought stress caused oxidative stress by excessive production of reactive oxygen species (ROS) which led to reduced growth and yield formation in all maize hybrids; nevertheless, negative effects of drought stress were more prominent in Run Nong 35. Drought-induced osmolyte accumulation and strong enzymatic and non-enzymatic defense systems prevented the severe damage in Dong Dan 80. Overall performance of all maize hybrids under drought stress was recorded as: Dong Dan 80 > Wan Dan 13 > Run Nong 35 with 6.39, 7.35, and 16.55% yield reductions. Consequently, these biochemical traits and differential physiological responses might be helpful to develop drought tolerance genotypes that can withstand water-deficit conditions with minimum yield losses.

Despite significant improvements in the technical aspects of cancer diagnosis and
management, it is still a leading cause of mortality worldwide. Although, the development
of a variety of therapeutic strategies with effective mechanisms of action is increasing, the
advanced understanding of molecular mechanisms of cancer initiation and progression is
still the important consequence. Reactive oxygen species (ROS) with great concern due to
the ability to modulate cell survival and cell death signaling pathways are could be
considered to design the effective anti-cancer strategies. Several anti-cancer agents used
for the treatment of various cancers regulates ROSs generation which subsequently
modulate the pro-apoptotic molecules, expression of various transcription factors
including Sp1, AP1, NF-kβ, and other pro-oncogenic genes that are engaged in cancer cell
proliferation, survival and metastasis. Concentration dependent ROS has distinct role in
different cancer processes like in apoptosis, cancer survival, autophagy, angiogenesis,
metastasis, and inflammation. Radiation and potent agents used in chemotherapy are
working on the phenomenon of ROS generation that inhibit cancer process. With the
intense understanding of ROS’s role in the particular cancer process which is inevitable in
cancer, may be used in health care to improve patient’s survival rate. The current review
presents all the proposed molecular interactions of ROS with their known cellular targets
in cancer cell.

Le stress salin est l'un des principaux facteurs environnementaux limitant la croissance des plantes et entraînant des pertes de rendement des cultures céréalières. Il est ainsi impératif de développer des variétés plus tolérantes à la salinité afin d’augmenter leurs rendements et assurer la sécurité alimentaire. La voie signalétique reliant la perception du stress salin à la réponse cellulaire, encore peu connue, a été abordée ici par l’étude des protéines RSS1-like conservées chez les plantes. La protéine RSS1 (Rice Salt Sensitive 1) du riz joue un rôle primordial dans la tolérance au stress salin en agissant à l’interface entre la perception des stress et le contrôle du développement et de la division dans les méristèmes. Lors de ce travail, l'homologue de RSS1 nommé TdRL1 (Triticum durum RSS-Like 1) a été isolé à partir de la variété tunisienne de blé dur “Oum Rabiaa“. Nous avons démontré que TdRL1 porte les motifs D et DEN-Box conservés impliqués dans la régulation post...

Oxidative stress, resulting from excessive levels of ROS in semen, has a negative impact on functional parameters and sperm fertility. In this study we examined the influence of the oxidative stress induced by hydrogen peroxide (H2O2) in ovine sperm motility after thawing and catalase (CAT) ability to preserve sperm motility. Semen was incubated at 37°C with 100 µM H2O2, 1 U catalase + 100 µM H2O2 or no treatment, for 30 min. Immediately after adding treatments, sperm motility was determined by computer-assisted semen analysis (CASA). Incubation with H2O2 led to a significant (P < 0.05) decrease in motility parameters whereas catalase prevented a decline in motility secondary to oxidative stress. After 30 min of incubation with H2O2, total motility (12.0% vs. control 73.0%, H2O2 +CAT 70.0%), progressive motility (0.0% vs. control 19.0%, H2O2 +CAT 19.0%) and rapid motility (1.0% vs. control 43.0%, H2O2 +CAT 40.0%) decreased significantly (P < 0.05), whereas percentage of static...