Elimination Of Peroxide Research Articles

Polyamino Acid Based Zwitterionic Coating can Inhibit Coagulation and Inflammation Through Anti-Fouling and Restoring Microenvironment.

Protein adhesion and thrombosis formation caused by limited surface properties pose great challenges to biomedical implants. Although various hydrophilic coating or drug release coatings are reported, the single coating cannot cope with cases under the condition of complex physiological environment, which causes the coating effect is limited. In this study, a polyamino acid-derived zwitterionic coating is constructed to eliminate reactive oxygen species (ROS) in the microenvironment. It is demonstrated that the coating has excellent hydrophilicity, stability, and lubricity, and can obviously prevent protein adhesion. At the same time, the coating can eliminate hydrogen peroxide and maintain the stability of the microenvironment. The in vivo and in vitro experiments show that the coating has good biocompatibility, and inhibits thrombus. Amino acid zwitterion coating prevents protein deposition, alleviates the inflammatory process, inhibit of thrombosis, reduces the risk of implantable medical devices, and prolongs their service time. Hence, the work paves a new way to develop amino acid based zwitterionic polymer coating that can reduce the implant complications.

A manganese doping deficient cerium base metal organic framework as radical scavenger for highly-durable proton exchange membrane water electrolysis

Eliminating hydrogen peroxide and free radicals from electrochemical reactions is crucial for mitigating chemical degradation and improving the durability of proton exchange membranes (PEMs). Herein, we prepare a metal–organic framework containing manganese and cerium ions that possesses oxygen vacancy defects and amino functional groups. The prepared Ce4MnBDC-NH2 acts as a catalyst for H2O2 decomposition and as a free radical scavenger, and it is incorporated into a perfluorosulfonic acid (PFSA) ionomer matrix. Featuring large pore volume, high porosity, and abundant amino groups, the Ce4MnBDC-NH2 is locked in a PEM. The obtained Ce4Mn-NH2BDC@PFSA composite membrane exhibits high dimensional stability, excellent proton conductivity and low high-frequency impedance, yielding a proton conductivity of up to 137 mS cm–1 and superior water electrolysis performance of up to 1.83 V at 3.0 A cm–2. Moreover, the obtained Ce4Mn-NH2BDC@PFSA membrane experiences lower weight loss during the Fenton reaction, a low fluoride-ion release rate, and excellent stability in high current density durability testing: its decay rate is only 5.2 μV h–1, which is lower than that of CeO2@PFSA and Nafion 117 membranes. This work provides a promising method to prepare efficient free radical scavengers for steady-state PEM water electrolysis.

Evolution of the peroxiredoxin gene family: an antioxidant enzyme in the context of hypoxia-induced by aquatic mammals dives

Peroxiredoxins are a group of antioxidant enzymes that play a crucial role in eliminating hydrogen peroxide (H2O2) produced during cellular metabolism. In conditions such as tissue ischemia/reperfusion, H2O2 production is heightened. This scenario is recurrent in aquatic mammals, such as cetaceans and pinnipeds, when they perform breath-hold dives that lead to depletion of oxygen stores and cell hypoxia due to prolonged submersion. In such circumstances, peroxiredoxins are essential for regulating metabolism and preventing oxidative damage. Thus, our objective was to investigate evolutionary patterns of the peroxiredoxin gene family among aquatic mammalian species. Accordingly, we identified the number of ortholog and paralog genes among mammals, examining events of gene duplication, patterns of chromosomal distribution, and adaptive selection. We found that most subtypes of peroxiredoxins are characterized by single-copy genes with minimal missing data, with PRDX1, the most highly expressed subtype found in both the nucleus and cytoplasm, exhibiting an increase in gene copies in aquatic mammals, particularly in pinnipeds. The distribution of the copies was dispersed along the genome and the majority were retrocopies of the main coding sequence with little divergence among them. We also found evidence of positive selection in the PRDX3 gene, especially in a convergent mutation among two deepest-diving species, cuvier’s beaked whale and southern elephant seal in which the amino acid had radical physical-chemical property change, possibly affecting the protein function. These results suggest that the peroxiredoxin gene family has a role in the evolution of aquatic mammals by reducing oxidative damage intrinsic to diving behavior in these species. FAPESP - São Paulo Research Foundation. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Comparative transcriptomes reveal molecular mechanisms of apple blossoms of different tolerance genotypes to chilling injury.

Apple (Malus domestica, Borkh.) is one of the four largest fruits in the world. Freezing damage during the flowering period of apples is one of the main factors leading to the reduction or even extinction of apple production. Molecular breeding of hardy apples is a good solution to these problems. However, the current screening of cold tolerance genes still needs to be resolved. Therefore, in this article, the transcriptome detection and cold tolerance gene screening during the cold adaptation process of apple were studied in order to obtain potential cold-resistant genes. Herein, two high-quality apple tree species (Malus robusta Rehd and M. domestica) were used for cold adaptation experiments and studied under different low-temperature stress conditions (0, -2 and -4°C). The antioxidant levels of two apple flower tissues were tested, and the transcriptome of the flowers after cold culture was tested by next-generation sequencing technology. Antioxidant test results show that the elimination of peroxides in M. robusta Rehd and the adjustment of the expression of antioxidant enzymes promote the cold resistance of this variety of apples. Functional enrichment found that the expression of enzyme activity, cell wall and cell membrane structure, glucose metabolism/gluconeogenesis, and signal transmission are the main biological processes that affect the differences in the cold resistance characteristics of the two apples. In addition, three potential cold-resistant genes AtERF4, RuBisCO activase 1, and an unknown gene (ID: MD09G1075000) were screened. In this study, three potential cold-resistant genes (AtERF4, RuBisCO activase 1, and an unknown gene [ID: MD09G1075000]) and three cold-repressed differential genes (AtDTX29, XTH1, and TLP) were screened.

Genome-wide identification of ascorbate peroxidase (APX) gene family and the function of SmAPX2 under high temperature stress in eggplant

Ascorbate peroxidase (APX) plays pivotal roles in regulating diverse biological processes in plants against biotic and abiotic stresses by eliminating hydrogen peroxide (H2O2). However, the function and information of APX gene family members in eggplant's response to high temperature stress remain largely unclear. Herein, we have identified nine APXs in the eggplant genome (SmAPXs), which were classified into three clades and the members of each clade exhibited similar gene structures and motifs. SmAPXs were distributed on seven chromosomes and contained phytohormone responsiveness-, defense and stress-related, and transcription factors binding cis-elements within their promoters. Transcript expressions of some SmAPXs, especially SmAPX2 that localize in cytomembrane and cytoplasm, were up-regulated by high temperature and ABA treatment. SmAPX2 exhibits APX enzyme activity, which enables to catalyze oxidation of ascorbic acid by H2O2in vitro and alleviate the H2O2 accumulation under high temperature stress by SmAPX2 transient expression in vivo. SmAPX2 silencing decreased eggplant's tolerance to high temperature stress, accompanied by transcript expression down-regulation of high temperature defense-related and ABA-response-related genes, reduction of APX enzyme activity, and increase of H2O2 content. These data provide comprehensive overview of SmAPX gene family, and indicate that SmAPX2 positively functions in eggplant response to high temperature stress.

Green ultrasound-assisted extraction of fish oil from rainbow trout intestines and purification with adsorbents

This study explored the application of green ultrasound-assisted technology for the extraction of oil from the intestines of rainbow trout. Purification methodologies were incorporated using adsorbents in order to enhance the quality of the extracted oil, which was evaluated based on its color, peroxide value (POV), free fatty acids, organic pollutants, and fatty acid composition. The extraction condition for maximum oil recovery was 60 °C for 30 min, with the addition of 1 g of sodium chloride and a water-to-sample ratio of 0:2. The analysis indicated that silica gel exhibited the highest efficiency as an adsorbent for the elimination of peroxides from extracted oil, with optimal results achieved after adsorption for 60 min. Despite undergoing purification, the POV of fish oil still exceeded the quality standard established by the CODEX Alimentarius Commission. In order to optimize the extraction process, the incorporation of antioxidants, including gallic acid, tannic acid, and Aronia (black chokeberry) powder, was implemented before the oil refining process. The integration of antioxidants and purification further lowered the POV and mitigated the production of organic pollutants, concurrently enhancing oil quality compared to without antioxidants. Notably, the incorporation of antioxidants during the initial stages of the extraction process resulted in a significant increase in the average concentrations of essential polyunsaturated fatty acids (PUFAs) in the final products. Overall, this study revealed that Aronia has the potential to serve as a natural, less-costly antioxidant alternative to pure antioxidants, such as tannic acid and gallic acid. Furthermore, the potential nutritional value of the final refined oil sample derived from rainbow trout intestines can be improved in terms of ω-3 fatty acid content by the developed method.

A STING pathway-activatable contrast agent for MRI-guided tumor immunoferroptosis synergistic therapy

The immunotherapy efficiency of stimulator of interferon genes (STING)-activatable drugs (e.g., 7-ethyl-10-hydroxycamptothecin, SN38) is limited by their non-specificity to tumor cells and the slow excretion of the DNA-containing exosomes from the treated cancer cells. The efficacy of tumor ferroptosis therapy is always limited by the elimination of lipid peroxides (LPO) by the pathways of glutathione peroxidase 4 (GPX4), dihydroorotate dehydrogenase (DHODH) and ferroptosis suppressor protein 1(FSP1). To solve these problems, in this study, we developed a STING pathway-activatable contrast agent (i.e., FeGd-HN@TA-Fe2+-SN38 nanoparticles) for magnetic resonance imaging (MRI)-guided tumor immunoferroptosis synergistic therapy. The remarkable in vivo MRI performance of FeGd-HN@TA-Fe2+-SN38 is attributed to its high accumulation at tumor location, the high relaxivities of FeGd-HN core, and the pH-sensitive TA-Fe2+-SN38 layer. The effectiveness and biosafety of the immunoferroptosis synergistic therapy induced by FeGd-HN@TA-Fe2+-SN38 are demonstrated by the in vivo investigations on the 4T1 tumor-bearing mice. The mechanisms of in vivo immunoferroptosis synergistic therapy by FeGd-HN@TA-Fe2+-SN38 are demonstrated by measurements of in vivo ROS, LPO, GPX4 and SLC7A11 levels, the intratumor matured DCs and CD8+ T cells, the protein expresion of STING and IRF-3, and the secretion of IFN-β and IFN-γ.

Hypoxia‐Responsive Nanoscale Coordination Polymer Enhances the Crosstalk Between Ferroptosis and Immunotherapy

AbstractThe immunosuppressive tumor microenvironment (TME) severely limits the clinical applications of cancer immunotherapy. Herein, a hypoxia‐responsive delivery system is constructed simply by coordinating ferric (Fe3+) with mitoxantrone (MTO), sulfasalazine (SAS), and hypoxia‐sensitive dopamine derivative of polyethylene glycol (PEG) using “one‐pot” reaction for the “closed‐loop” synergistic enhancement of ferroptosis and immunotherapy. Hypoxia‐sensitive PEG ensures the integrity of delivery system in circulation to prevent the premature leakage of drugs, and the detachment of PEG in the interior hypoxic TME can facilitate the deep penetration and the subsequent tumor uptake. The released iron and MTO induce the generation of reactive oxygen species (ROS), while SAS inhibits the elimination of lipid peroxides by inhibiting SLC7A11 subunit of glutamate‐cystine antiporter, which synergistically induces immunogenic ferroptosis to promote dendritic cells maturation and T cells activation. The activated CD8+ T cells then release interferon γ (IFN‐γ) and in turn enhance ferroptosis by downregulating the expression of SLC7A11. As a result, the “closed‐loop” synergistic enhancement between ferroptosis and immunotherapy significantly prevents tumor growth and prolonged survival time of tumor‐bearing mice with no obvious systemic toxicity. The excellent therapeutic effect together with the scalable synthesis and controllable quality will promise its translation to clinic as a novel immunotherapy.

THE EFFECT OF HEAVY METAL IONS ON THE PEROXIDASE ACTIVITY IN ARABIDOPSIS THALIANA

The biosphere pollution with the heavy metals (HM) has increased significantly in recent decades due to human activity. Plants can accumulate and concentrate HM, which negatively affects their growth, productivity and quality of agricultural products. Some HM, such as copper, belong to the group of biogenic elements that, in low concentrations, are essential for the normal functioning of plant organisms. Other HM such as cadmium are toxic even in low concentrations. The toxicity of HM is related to oxidative damage. In the plant cell, the antioxidant system provides protection against this kind of stress. However, data on changes in antioxidant enzyme activities in the early stage of the cellular response to HM-induced stress remain scarce. Therefore, we focused our research on studying peroxidase (POD) activity changes in Arabidopsis thaliana under conditions of rapid uptake of copper and cadmium ions into leaf tissue. For the experiments, 4.5–5-week-old A. thaliana plants were used. The plants were incubated on 0.5x MS liquid medium containing copper or cadmium chloride at concentrations of 0.1, 0.5 and 5 mM. The HM salt treatment was carried out in the dark at 20 °C for 2 (short-term stress) and 12 (long-term stress) hours. After that, the leaves were frozen and the POD activity was measured. Evaluation of the effects of Cd2+ and Cu2+ ions shows that these HM cause a decrease in POD activity after 2 hours and its increase after 12 hours of treatment. Therefore, modulation of POD activity is a component of the HM stress response in A. thaliana. Analysis of the available data revealed that the enzymes POD and CAT, which eliminate hydrogen peroxide, can partially replace each other and thus provide cellular protection in different phases of the stress response.

The Role of Phospholipase Activity of Peroxiredoxin 6 in Its Transmembrane Transport and Protective Properties

Peroxiredoxin 6 (Prdx6) is a multifunctional eukaryotic antioxidant enzyme. Mammalian Prdx6 possesses peroxidase activity against a wide range of organic and inorganic hydroperoxides, as well as exhibits phospholipase A2 (aiPLA2) activity, which plays an important role in the reduction of oxidized phospholipids and cell membrane remodeling. Exogenous Prdx6 has recently been shown to be able to penetrate inside the cell. We hypothesized that this entry may be due to the phospholipase activity of Prdx6. Experiments using exogenous Prdx6 in three cell lines (3T3, A549, RAW 264.7) demonstrated that it is the phospholipase activity that promotes its penetration into the cell. Overoxidation of Prdx6 led to a suppression of the peroxidase activity and a 3-to-4-fold growth of aiPLA2, which enhanced the efficiency of its transmembrane transport into the cells by up to 15 times. A mutant form of Prdx6-S32A with an inactivated phospholipase center turned out to be unable to enter the cells in both the reduced and oxidized state of the peroxidase active center. Previously, we have shown that exogenous Prdx6 has a significant radioprotective action. However, the role of phospholipase activity in the radioprotective effects of Prdx6 remained unstudied. Trials with the mutant Prdx6-S32A form, with the use of a total irradiation model in mice, showed a nearly 50% reduction of the radioprotective effect upon aiPLA2 loss. Such a significant decrease in the radioprotective action may be due to the inability of Prdx6-S32A to penetrate animal cells, which prevents its reduction by the natural intracellular reducing agent glutathione S-transferase (πGST) and lowers the efficiency of elimination of peroxides formed from the effect of ionizing radiation. Thus, phospholipase activity may play an important role in the reduction of oxidized Prdx6 and manifestation of its antioxidant properties.

The gill epithelial cell lines RTgill-W1, from Rainbow trout and ASG-10, from Atlantic salmon, exert different toxicity profiles towards rotenone

In order to ensure the proper use and interpretation of results from laboratory test systems, it is important to know the characteristics of your test system. Here we compare mitochondria and the handling of reactive oxygen species (ROS) in two gill epithelial cell lines, the well-known RTgill-W1 cell line from Rainbow trout and the newly established ASG-10 cell line from Atlantic salmon. Rotenone was used to trigger ROS production. Rotenone reduced metabolic activity and induced cell death in both cell lines, with RTgill-W1 far more sensitive than ASG-10. In untreated cells, the mitochondria appear to be more fragmented in RTgill-W1 cells compared to ASG-10 cells. Furthermore, rotenone induced mitochondrial fragmentation, reduced mitochondria membrane potential (Δψm) and increased ROS generation in both cell lines. Glutathione (GSH) and catalase is important to maintain the cellular oxidative balance by eliminating hydrogen peroxide (H2O2). In response to rotenone, both GSH and catalase depletion were observed in the RTgill-W1 cells. In contrast, no changes were found in the GSH levels in ASG-10, while the catalase activity was increased. In summary, the two salmonid gill cell lines have different tolerance towards ROS, probably caused by differences in mitochondrial status as well as in GSH and catalase activities. This should be taken into consideration with the selection of experimental model and interpretation of results.Graphical abstract

In-vitro evaluation of antimicrobial and antioxidant activity of Embelica officinalis extract on different strains on gram positive and negative bacteria

The present study was carried out to evaluate the in vitro antimicrobial and antioxidant activity of Emblica officinalis extract powder. The antimicrobial activity was assessed against gram positive and gram negative bacteria namely E.coli, Pseudomonas fluoresces, Bacillus subtilis, S.aureus, by agar well diffusion method. Quantitative antimicrobial susceptibility testing method, i.e., determination of minimum inhibitory concentration (MIC) by serial broth dilution was carried out on the different bacterial strains. The diameter of the zone of inhibition (ZOI) for the strains tested against was recorded and compared with the standard (Gentamicin, in case of bacteria). The results of the present study also revealed that Amla extract powder can scavenge free radicals or reactive oxygen species under in vitro conditions. The elimination of hydrogen peroxide by Amla powder may be attributed to phenolic compounds. The total phenolic content in the Emblica officinalis extract powder measured by the Folin Ciocalteau reagent in terms of gallic acid equivalents (GAE) was found to be 390.8mg/g. The possible reason for antibacterial activity of Amla extract powder might be the presence of tannins in the fruits.

IDH2-mediated regulation of the biogenesis of the oxidative phosphorylation system.

Several subunits in the matrix domain of mitochondrial complex I (CI) have been posited to be redox sensors for CI, but how elevated levels of reactive oxygen species (ROS) impinge on CI assembly is unknown. We report that genetic disruption of the mitochondrial NADPH-generating enzyme, isocitrate dehydrogenase 2 (IDH2), in Drosophila flight muscles results in elevated ROS levels and impairment of assembly of the oxidative phosphorylation system (OXPHOS). Mechanistically, this begins with an inhibition of biosynthesis of the matrix domain of CI and progresses to involve multiple OXPHOS complexes. Despite activation of multiple compensatory mechanisms, including enhanced coenzyme Q biosynthesis and the mitochondrial unfolded protein response, ferroptotic cell death ensues. Disruption of enzymes that eliminate hydrogen peroxide, but not those that eliminate the superoxide radical, recapitulates the phenotype, thereby implicating hydrogen peroxide as the signaling molecule involved. Thus, IDH2 modulates the assembly of the matrix domain of CI and ultimately that of the entire OXPHOS.

S-Glycosylation of Fluensulfone in Tomatoes: An Important Way of Fluensulfone Metabolism.

Fluensulfone (FSF) becomes increasingly popular because of its nonfumigation application method. However, studies on the metabolic mechanism of FSF in plants are lacking. Here, tomato seedling was cultivated in hydroponic media to investigate the connection among FSF's metabolism in tomato, the regulation of tomato endogenous glycosides, and the elimination of hydrogen peroxide in tomato cells. The accumulation of FSF was only detected in the lower stems of tomatoes; FSF was mainly metabolized into S-glycosylated conjugates in the roots, and the roots were the tissues with the highest metabolite content; and no FSF and metabolites were detected in the upper leaves. In response to FSF stress (2 mg/L for 7 d), the content of sugar and glycosides in the stems of tomato seedlings significantly increased. The amount of some compounds on the pathway related to glucose was affected by FSF. The three precursor compounds (homomethioine, isoleucine, and l-tyrosine) in the pathway of glucosinolate biosynthesis increased significantly under the stress of FSF, which indicates that FSF may compete with them for UGT74B1. Besides, FSF-induced flavonoid glycosides may play a role in the process of removing hydrogen peroxide. This research provides inspiration for the fate of many xenobiotics containing sulfonyl groups in plants.

Characterization of a novel catalase gene and its response to low temperature stress in noble scallop Chlamys nobilis with different total carotenoids content

Antioxidant system plays important roles in organisms under environmental stress by eliminating hydrogen peroxide. Catalase is an indispensable antioxidant protein that is essential for maintaining the redox balance of innate immune system. In this study, a novel catalase gene was first cloned from noble scallop Chlamys nobilis (named as CnCAT), and then its potential roles in respond to low temperature stress were investigated using golden (rich in carotenoids) and brown (less in carotenoids) C. nobilis. The CnCAT contains an ORF of 1569 bp encoding 522 amino acids. Phylogenetic tree analysis of CnCAT showed it had a higher identity with other molluscs. The distribution analysis indicated that the highest and the lowest expression level of CnCAT were found in gill and adductor respectively. Under low temperature stress, CnCAT expression level and CAT activity were significantly up-regulated, suggesting they play important roles in defence against the low temperature stress. In addition, the expression levels of CnCAT and CAT in golden scallops were significantly higher than those of brown scallops under low temperature stress, suggesting that the high carotenoid levels in the golden scallops may strengthen their toleration to low temperature stress. Collectively, these results indicated that CnCAT plays vital roles in the antioxidant system, and carotenoids in golden scallops may enhance their resistance to low temperature stress. These results will provide us a better understand to the immune response of scallops under low temperature stress.

Thrombus-targeted nanoparticles for thrombin-triggered thrombolysis and local inflammatory microenvironment regulation

Thrombus related diseases seriously threaten human's health and life. The drawbacks of thrombolytic drugs, such as poor targeting ability and unexpected bleeding complications limit their clinical application. Thus, targeted delivery and controlled release of drugs at local thrombus sites to achieve efficient thrombolysis is an urgent event to be resolved. Herein, we developed an intelligent system MnO2/uPA@pep-Fuco for precise thrombolysis and thrombus inflammatory microenvironment remodeling. MnO2/uPA@pep-Fuco exhibited an excellent thrombus targeting ability via the high affinity of fucoidan (Fuco) for P-selectin overexpressed by activated platelets. And then pep-Fuco modified onto the surface of mesopore could be removed to release urokinase (uPA) locally under the high level of thrombin microenvironment in thrombus site. Meanwhile, due to the catalase-like activity of MnO2 nanoplatform, MnO2/uPA@pep-Fuco could regulate the inflammatory thrombus microenvironment by eliminating hydrogen peroxide (H2O2), so as to achieve a collaborative thrombolysis therapy. In ferric chloride (FeCl3)-induced carotid thrombus models, MnO2/uPA@pep-Fuco specifically targeted to the obstructive artery (3.43 times that of the normal artery) and significantly decreased the percentage of thrombus closure (5.99 ± 5.07%), demonstrating the superior thrombolysis ability. In addition, the significantly reduced tail bleeding time suggested MnO2/uPA@pep-Fuco might possess a low risk of bleeding complications.

Cibacron blue F3GA incorporated immobilized metal chelate affinity sorbent as a high efficient affinity immobilization materials for catalase enzyme

Catalase is a metalloenzyme commonly found in almost all plant and animal tissues and catalyzes the conversion of hydrogen peroxide to less reactive molecules. It is used for the elimination of hydrogen peroxide in biological, biomedical, food and textile applications. For this purpose, a novel affinity sorbent [poly(methacrylic acid- N-isopropyl acrylamide-CB-Fe3+, (p(MAA-NIPAAM)-CB-Fe3+)] for the determination and it was first developed using MAA and NIPAAM monomers. After characterization with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), adsorption parameters were determined. Reusability of p(MAA-NIPAAM)-CB-Fe3+ sorbent was determined after by determining the appropriate desorption agent for desorption of adsorbed catalase in the developed sorbent. It was determined that catalase adsorption could be performed with 0.01 g of sorbent in 45 min. The maximum adsorption capacity for catalase adsorption was determined as 243.17 mg/g with the use of sorbent. The operational and storage stability of the immobilized catalase was found to be high as expected. The conversion of H2O2 can be successfully performed by the immobilized enzyme in the prepared sorbent. It has been proven that the affinity of catalase for its substrate is increased by immobilization.

Human sperm functioning is related to the aquaporin-mediated water and hydrogen peroxide transport regulation

Aquaporins (AQPs) are transmembrane water channels and some of them are permeable in addition to water to other small solutes including hydrogen peroxide. The sperm cells of mammals and fishes express different AQPs, although there is no agreement in the literature on their localization. In humans, AQP3 and AQP11 are expressed mainly in the tail, AQP7 in the head and AQP8 in the midpiece. Thanks to the results of experiments with KO mice and to data obtained by comparing sub-fertile patients with normospermic subjects, the importance of AQPs for the normal functioning of sperms to ensure normal fertility emerged. AQP3, AQP7 and AQP11 appeared involved in the sperm volume regulation, a key role for fertility because osmoadaptation protect the sperm against a swelling and tail bending that could affect sperm motility. AQP8 seems to have a fundamental role in regulating the elimination of hydrogen peroxide, the most abundant reactive oxygen species (ROS), and therefore in the response to oxidative stress. In this review, the human AQPs expression, their localization and functions, as well as their relevance in normal fertility are discussed. To understand better the AQPs role in human sperm functionality, the results of studies obtained in other animal species were also considered.

Provenance-specific ecophysiological responses to drought in Cunninghamia lanceolata

Abstract Aims Cunninghamia lanceolata is one of the most important coniferous species in southern China, but its high sensitivity to drought restricts its expansion. Understanding the intraspecific variation of physiological responses to drought can help us manage this plantation better. Methods We selected 3-year-old seedlings of C. lanceolata, which originated from the low precipitation (LP), middle precipitation (MP) and high precipitation (HP) habitats, respectively. Seedlings were grown under drought stress (20% of soil volumetric water content) for 40 days. The ecophysiological responses and adaptive strategies with different drought tolerance were investigated. Important Findings LP provenance possessed the best tolerance to drought stress, suggesting that considerably increased carbohydrates and nitrogen-containing compounds as osmotic protective materials, which were driven by fast carbon and nitrogen metabolisms. In addition, the highest peroxidase activity could effectively eliminate hydrogen peroxide in drought-stressed LP provenance. The MP provenance reserved a large amount of non-structural carbohydrates, which may act as a certain buffer for encountering drought stress. Importantly, timely closure of stomata to reduce needle transpiration when encountering a water deficiency would help them adapt to long-term drought. MP provenance adopted a conservative water-saving strategy. However, HP provenance regulated root growth (increased root/shoot ratio) and reduced penetration potential to help them absorb water. The different strategies among provenances may be related to the long-term domestication of the geographical environments. Therefore, our results underline the importance of provenance-specific responses to drought stress. It is highly significant to accelerate the selection of drought-resistant germplasms and to cultivate high-yield plantations in the future.

Antioxidant cytochrome c-like activity of para-Mn(III)TMPyP

Manganese porphyrins are well-known protectors against the deleterious effects of pro-oxidant species such as superoxide ions and hydrogen peroxide. The present study investigated the antioxidant cytochrome c-like activities of Mn(III)TMPyP [meso-tetrakis (4-N-methyl pyridinium) porphyrin] against superoxide ion and hydrogen peroxide that remained unexplored for this porphyrin. The association of TMPyP with a model of the inner mitochondrial membrane, cardiolipin (CL)-containing liposomes, shifted +30 mV vs. NHE (normal hydrogen electrode) redox potential of the Mn(II)/Mn(III) redox couple. In CL-containing liposomes, Mn(III)TMPyP was reduced by superoxide ions and recycled by Fe(III)cytochrome c to the oxidized form. Similarly, isolated rat liver mitoplasts added to a sample of Mn(II)TMPyP promoted immediate porphyrin reoxidation by electron transfer to the respiratory chain. These results show that Mn(III)TMPyP can act as an additional pool of Fe(III)cytochrome c capable of transferring electrons that escape from the IV complex back into the respiratory chain. Unlike Fe(II)cytochrome c, Mn(II)TMPyP was not efficient for hydrogen peroxide clearance. Therefore, by reducing cytochrome c, Mn(II)TMPyP can indirectly contribute to hydrogen peroxide elimination.