Mechanisms of aging: an appraisal of the oxidative stress hypothesis

A reflexion on the oxidative stress and animal welfare: a review

A wide range of studies have documented the role of oxidative stress in the development of chronic pathological disorders and even in the aging itself. However, its significance to modern animal health and welfare remains neglected. Oxidative stress in biological systems refers to a disturbance in the balance between pro-oxidants and antioxidants in favour of the former, leading to potential damage of biomolecules. In farm animals, oxidative stress may be involved in several pathological conditions, including those that are relevant for animal production and the general welfare of the individuals, resulting in some cases in irreversible losses. The oxidative stress concept and how it may result in disease or be prevented are complex questions with no simple answers and therefore, call professionals for deep reflection, to maintain a high standard of animal welfare and production. The aim of this review was to gather relevant information on the characteristics of pro-oxidants and antioxidant as well as their significance in animal production systems.

Evaluation of the Protective Role of Vitamin E against ROS-Driven Lipid Oxidation in Model Cell Membranes

Reactive oxygen species (ROS) are chemically reactive oxygen-containing compounds generated by various factors in the body. Antioxidants mitigate the damaging effects of ROS by playing a critical role in regulating redox balance and signaling. In this study, the interplay between reactive oxygen species (ROS) and antioxidants in the context of lipid dynamics were investigated. The interaction between hydrogen peroxide (H2O2) as an ROS and vitamin E (α-tocopherol) as an antioxidant was examined. Model membranes containing both saturated and unsaturated lipids served as experimental platforms to investigate the influence of H2O2 on phospholipid unsaturation and the role of antioxidants in this process. The results demonstrated that H2O2 has a negative effect on membrane stability and disrupts the lipid membrane structure, whereas the presence of antioxidants protects the lipid membrane from the detrimental effects of ROS. The model membranes used here are a useful tool for understanding ROS-antioxidant interactions at the molecular level in vitro.

Ecotoxicological effects of the emerging contaminant ivermectin on Rhinella arenarum: A comparative study of active ingredient and commercial formulation

Ivermectin (IVM) is a broad-spectrum veterinary antiparasitic used worldwide in cattle breeding. The aim of this study was to evaluate the lethal effects of the active ingredient and a commercial formulation of IVM (1 % active ingredient) in the embryonic stage (S. 4-6) and larval stage (S. 25) of the South American amphibian Rhinella arenarum through chronic standardized bioassays. Also, behavior analysis and oxidative stress and cholinergic effects biomarkers were analyzed at 1, 10 and 100 μg IVM/L concentrations. For the embryonic stage, the active ingredient (96 h- LC50: 15900 μg/L) was more toxic than the commercial formulation (96 h-LC50: 51230 μg/L) during the acute period, while at chronic exposure the commercial formulation was more toxic (504 h-LC50: 10.25 μg/L), compared to the active ingredient (504 h-LC50: 312.80 μg/L). For the larval stage, in acute exposure, the active ingredient (96 h-LC50: 800 μg/L) was more toxic than the commercial formulation (96 h-LC50: 1550 μg/L). In the chronic exposure, the commercial formulation (504 h-LC50: 77.33 μg/L) was more toxic than the active ingredient (504 h-LC50: 195.25 μg/L). Overall, larvae exhibited greater sensitivity to both the active ingredient and the commercial formulation. However, during chronic exposure, embryos were more sensitive to the commercial formulation than larvae. The commercial formulation primarily induced oxidative stress, and both forms of the compound affected behavior and cholinergic effect biomarkers, even at low environmentally relevant concentrations (1 μg/L). These results highlight the potential impact of IVM on aquatic ecosystems.

The impact of chemical pollution across major life transitions: a meta-analysis on oxidative stress in amphibians

Among human actions threatening biodiversity, the release of anthropogenic chemical pollutants which have become ubiquitous in the environment, is a major concern. Chemical pollution can induce damage to macromolecules by causing the overproduction of reactive oxygen species, affecting the redox balance of animals. In species undergoing metamorphosis (i.e. the vast majority of the extant animal species), antioxidant responses to chemical pollution may differ between pre- and post-metamorphic stages. Here, we meta-analysed (N = 104 studies, k = 2283 estimates) the impact of chemical pollution on redox balance across the three major amphibian life stages (embryo, tadpole, adult). Before metamorphosis, embryos did not experience any redox change while tadpoles activate their antioxidant pathways and do not show increased oxidative damage from pollutants. Tadpoles may have evolved stronger defences against pollutants to reach post-metamorphic life stages. In contrast, post-metamorphic individuals show only weak antioxidant responses and marked oxidative damage in lipids. The type of pollutant (i.e. organic versus inorganic) has contrasting effects across amphibian life stages. Our findings show a divergent evolution of the redox balance in response to pollutants across life transitions of metamorphosing amphibians, most probably a consequence of differences in the ecological and developmental processes of each life stage.

Physiological responses of the microalgae Thalassiosira weissflogii to the presence of the herbicide glyphosate in the medium

We evaluated changes in growth, chlorophyll fluorescence and basic physiological and biochemical parameters of the microalgae Thalassiosira weissflogii cells under the influence of the herbicide glyphosate in concentrations 0, 25, 95 and 150μgL-1 . The toxic effect of glyphosate on algae is weakly dependent on the level of cell mineral nutrition. High concentrations of the herbicide do not lead to the death of microalgae but block the process of algae cell division. An increase in the glyphosate concentration in the medium leads to a slowdown or stop of algal growth, a decrease in their final biomass, an increase in the production of reactive oxygen species (ROS), depolarisation of mitochondrial membranes and metabolic activity of algae. Glyphosate inhibits the photosynthetic activity of cells and inhibits the relative rate of electron transport in the photosynthetic apparatus. Glyphosate at the studied concentrations does not affect the size characteristics of cells and the intracellular content of chlorophyll in T. weissflogii . The studied herbicide or products of its decay retain their toxic properties in the environment for at least 9days. This result shows the need for further in-depth studies to assess the physiological response and possible acclimation changes in the functional state of oxygenic phototrophs in response to the herbicide action. The species specificity of microalgae to the effects of glyphosate in natural conditions is potentially dangerous due to a possible change in the species structure of biocoenoses, in particular, a decrease in the contribution of diatoms.

Aging Hallmarks and Progression and Age-Related Diseases: A Landscape View of Research Advancement

Aging is a dynamic, time-dependent process that is characterized by a gradual accumulation of cell damage. Continual functional decline in the intrinsic ability of living organisms to accurately regulate homeostasis leads to increased susceptibility and vulnerability to diseases. Many efforts have been put forth to understand and prevent the effects of aging. Thus, the major cellular and molecular hallmarks of aging have been identified, and their relationships to age-related diseases and malfunctions have been explored. Here, we use data from the CAS Content Collection to analyze the publication landscape of recent aging-related research. We review the advances in knowledge and delineate trends in research advancements on aging factors and attributes across time and geography. We also review the current concepts related to the major aging hallmarks on the molecular, cellular, and organismic level, age-associated diseases, with attention to brain aging and brain health, as well as the major biochemical processes associated with aging. Major age-related diseases have been outlined, and their correlations with the major aging features and attributes are explored. We hope this review will be helpful for apprehending the current knowledge in the field of aging mechanisms and progression, in an effort to further solve the remaining challenges and fulfill its potential.

A study on the delayed effect of tilapia skin collagen on skin aging for mice and its possible mechanism

OBJECTIVE

Study the possible mechanism and delayed effect of tilapia skin collagen on skin aging for mice.

MATERIALS AND METHODS

Kunming (KM) mice were randomly divided into the aging model group, the normal group, the positive control group (vitamin E) and the low, medium, high dose tilapia skin collagen groups (2.0, 4.0, 8.0 mg/g). The normal group was only injected with saline at the back and the neck. The other groups were injected subcutaneously with 5% D-galactose and ultraviolet light jointly to establish the aging model. After modeling, the positive control group was treated with a dose of 10% vitamin E once a day, and the low, medium, high dose tilapia skin collagen group was separately applied 2.0, 4.0, 8.0 mg/g of tilapia skin collagen for 40 days. The changes of skin tissue morphology, water content, hydroxyproline (Hyp) content, and superoxide dismutase (SOD) activity in mice were studied at the day 10, 20, 30, 40, 50.

RESULTS

Compared with the normal group, the skin of mice in the aging model group was thinner, looser, and the skin moisture content, Hyp content, SOD activity were all decreased. For mice of the low, medium, high dose tilapia skin collagen group, the thickness of dermis increased, possessing close arrangement, and the moisture content, Hyp content, SOD activity were up-regulated significantly, which effectively alleviated the aging process of skin. The dose of tilapia skin collagen was directly proportional to the anti-aging effect.

CONCLUSIONS

Tilapia skin collagen has an obvious effect on improving skin aging.

Six Functions of Respiration: Isn't It Time to Take Control over ROS Production in Mitochondria, and Aging Along with It?

Cellular respiration is associated with at least six distinct but intertwined biological functions. (1) biosynthesis of ATP from ADP and inorganic phosphate, (2) consumption of respiratory substrates, (3) support of membrane transport, (4) conversion of respiratory energy to heat, (5) removal of oxygen to prevent oxidative damage, and (6) generation of reactive oxygen species (ROS) as signaling molecules. Here we focus on function #6, which helps the organism control its mitochondria. The ROS bursts typically occur when the mitochondrial membrane potential (MMP) becomes too high, e.g., due to mitochondrial malfunction, leading to cardiolipin (CL) oxidation. Depending on the intensity of CL damage, specific programs for the elimination of damaged mitochondria (mitophagy), whole cells (apoptosis), or organisms (phenoptosis) can be activated. In particular, we consider those mechanisms that suppress ROS generation by enabling ATP synthesis at low MMP levels. We discuss evidence that the mild depolarization mechanism of direct ATP/ADP exchange across mammalian inner and outer mitochondrial membranes weakens with age. We review recent data showing that by protecting CL from oxidation, mitochondria-targeted antioxidants decrease lethality in response to many potentially deadly shock insults. Thus, targeting ROS- and CL-dependent pathways may prevent acute mortality and, hopefully, slow aging.

Water extract from Ligusticum chuanxiong delays the aging of Saccharomyces cerevisiae via improving antioxidant activity

Ligusticum chuanxiong is a common traditional edible-medicinal herb that has various pharmacological activities. However, its effects on Saccharomyces cerevisiae (S. cerevisiae) remains unknown. In this study, we found that water extract of Ligusticum chuanxiong (abbreviated as WEL) exhibited excellent free radical scavenging ability in-vitro. Moreover, WEL treatment could delay the aging of S. cerevisiae, an important food microorganism sensitive to reactive oxygen species (ROS) stress. Biochemical analyses revealed that WEL significantly increased the activity of antioxidant enzymes in S. cerevisiae, including superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), as well as their gene expression. As a result, ROS level was significantly decreased and accompanied with the decline of malondialdehyde (MDA), which represented a state of low oxidative stress. The reduction of oxidative stress could elevate S. cerevisiae's ethanol fermentation efficiency. Taken together, WEL plays a protective role against S. cerevisiae aging via improving antioxidant activity.

Current Trends in Anti-Aging Strategies

The process of aging manifests from a highly interconnected network of biological cascades resulting in the degradation and breakdown of every living organism over time. This natural development increases risk for numerous diseases and can be debilitating. Academic and industrial investigators have long sought to impede, or potentially reverse, aging in the hopes of alleviating clinical burden, restoring functionality, and promoting longevity. Despite widespread investigation, identifying impactful therapeutics has been hindered by narrow experimental validation and the lack of rigorous study design. In this review, we explore the current understanding of the biological mechanisms of aging and how this understanding both informs and limits interpreting data from experimental models based on these mechanisms. We also discuss select therapeutic strategies that have yielded promising data in these model systems with potential clinical translation. Lastly, we propose a unifying approach needed to rigorously vet current and future therapeutics and guide evaluation toward efficacious therapies.

The superoxide dismutase (SOD) genes family mediates the response of Nilaparvata lugens to jinggangmycin and sugar

Introduction: Brown planthopper (BPH), Nilaparvata lugens Stål (Hemiptera: Delphacidae), is a major rice pest causing significant damage to rice throughout the world. Intensive pesticide usage often causes resistance in these seasonal pests, mainly through the modulation of antioxidant machinery. The superoxide dismutase (SOD) gene family is known for regulating BPH response to pesticides. Methods: In the present study, we identified eight NlSOD genes from the NCBI using the BLASTP program. The bioinformatics analysis includes a phylogenetic tree, conserved domain, motifs, gene ontology (GO) analysis, Kyoto encyclopedia of genes and genomes (KEGG) pathways, and protein-protein interaction, highlighting the distinctive functional elements of NlSOD genes. Results and discussion: Additionally, the NlSOD genes showed expression in all developmental stages of BPH. Under three sugars (glucose, sucrose, and trehalose) treatment, the respective upregulation of NlSOD8, NlSOD6, and NlSOD2 was noted. The NlSOD1 induced significantly under jinggamycin (JGM) deduced its potential as a key regulator of BPH response to the pesticide. Our study has provided detailed knowledge of the NlSOD gene family in-silico analysis and the defensive response to insecticide and high sugar of BPH. We hope the results of this research will help to shed light on the resistance of BPH towards insecticide toxicity and high sugar and help to control it more efficiently.

Oxidative stress, inflammation and hormesis: The role of dietary and lifestyle modifications on aging

Oxidative stress (OS) is primarily caused by the formation of free radicals and reactive oxygen species; it is considered as one of the prominent factors in slowing down and degrading cellular machinery of an individual, and it eventually leads to aging and age-related diseases by its continuous higher state. The relation between molecular damage and OS should be particularized to understand the beginning of destruction at the cellular levels, extending outwards to affect tissues, organs, and ultimately to the organism. Several OS biomarkers, which are established at the biomolecular level, are useful in investigating the disease susceptibility during aging. Slowing down the aging process is a matter of reducing the rate of oxidative damage to the cellular machinery over time. The breakdown of homeostasis, the mild overcompensation, the reestablishment of homeostasis, and the adaptive nature of the process are the essential features of hormesis, which incorporates several factors, including calorie restriction, nutrition and lifestyle modifications that play an important role in reducing the OS. In the current review, along with the concept and theories of aging (with emphasis on free radical theory), various manifestations of OS with special attention on mitochondrial dysfunction and age-related diseases have been discussed. To alleviate the OS, hormetic approaches including caloric restriction, exercise, and nutrition have also been discussed.

Ligusticum chuanxiong Hort as a medicinal and edible plant foods: Antioxidant, anti-aging and neuroprotective properties in Caenorhabditis elegans

Ligusticum chuanxiong Hort. (CX) is a medicinal and edible plant including a variety of active substances, which may be an available resource for the treatment of related diseases. To expand the medicinal uses of CX, this study aims to explore the antioxidant, anti-aging and neuroprotective effects of the Ligusticum chuanxiong leaves (CXL) and rhizome (CXR) extracts. We first characterize CX phytochemical spectrum by LC-MS as well as antioxidant capacity. Acute toxicity, anti-oxidative stress capacity, lifespan and healthspan was evaluated in C elegans N2. Neuroprotective effect was evaluated in vitro and in vivo (C elegans CL4176 and CL2355). In this study, we detected 74 and 78 compounds from CXR and CXL, respectively, including phthalides, alkaloids, organic acids, terpenes, polyphenols and others. Furthermore, we found that CXs not only protect against oxidative stress, but also prolong the lifespan, alleviate lipofuscin, malondialdehyde (MDA) and reactive oxygen species (ROS) accumulation, and improve movement level, antioxidant enzyme activity in C elegans N₂. However, only CXR reduced the β-amyloid peptide (Aβ)-induced paralysis phenotype in CL4176s and alleviated chemosensory behavior dysfunction in CL2355s. In addition, CXR treatment reduced the production of Aβ and ROS, enhanced SOD activity in CL4176s. The possible mechanism of anti-aging of CXL and CXR is to promote the expression of related antioxidant pathway genes, increase the activity of antioxidant enzymes, and reduce the accumulation of ROS, which is dependent on DAF-16 and HSF-1 (only in CXR). CXR was able to activate antioxidase-related (sod-3 and sod-5) and heat shock protein genes (hsp-16.1 and hsp-70) expression, consequently ameliorating proteotoxicity related to Aβ aggregation. In summary, these findings demonstrate the antioxidant, anti-aging and neuroprotective (only in CXR) activities of the CX, which provide an important pharmacological basis for developing functional foods and drugs to relieve the symptoms of aging and AD. However, the material basis of neuroprotective activity and antiaging effects need to be elucidated, and the relationship between these activities should also be clarified in future studies.

Mechanisms of the ethanol extract of Gelidium amansii for slow aging in high-fat male Drosophila by metabolomic analysis

Gelidium amansii (GA) is a kind of red alga homologous to medicine and food and is distributed all over the world. Studies on GA are mainly focused on its polysaccharides, with little research on the ethanol extract. The ethanol extract of Gelidium amansii (GAE) was subjected to a reverse-phase column to obtain 7 components. Among them, 100% methanol solution (GAM), enriched with phytene-1,2-diol, exhibited the strongest DPPH free radical scavenging activity (IC50 = 0.17 mg mL-1). Subsequently, high-fat male flies (HMFs) were used as a model to explore the antioxidant and anti-aging effects of GAM in vivo. Studies showed that GAM can effectively prolong the lifespan of HMFs. When GAM concentrations were 0.2 and 1.0 mg mL-1, the average lifespan of HMFs was increased by 28.7 and 40.7%, respectively, while the longest lifespan of HMFs was increased by 20.55% and 32.88%, respectively. Further research revealed that GAM can significantly downregulate the levels of malondialdehyde (MDA) and protein carbonyl (PCO), and can significantly upregulate the levels of catalase (CAT) and total superoxide dismutase (T-SOD). In addition, by analyzing differential metabolites, we found that GAM relieves aging caused by oxidative stress by regulating amino acid, lipid, sugar, and energy metabolism. The GAM group significantly regulated the levels of adenine, cholic acid, glutamate, L-proline, niacin, and stachyose which tend to recover to the levels of the normal diet male fly (NMF) group. In general, our research provides ideas for the high-value utilization of GA and provides a lead compound for the research and development of anti-aging food or medicine.

Mechanism of Longevity Extension of Caenorhabditis elegans Induced by Schizophyllum commune Fermented Supernatant With Added Radix Puerariae

Schizophyllum commune (S. commune) fermented supernatant with added Radix Puerariae (SC-RP) showed significant antioxidant activity in our previous work. However, the possible lifespan and healthspan extending the capacity of Caenorhabditis elegans (C. elegans) and the underlying mechanism were not illuminated. In this study, the effect of SC-RP on extending the lifespan and improving stress resistance of C. elegans were examined. Additionally, the underlying lifespan extending molecular mechanisms of SC-RP were explored. Treated with SC-RP at 10 μg/mL, the lifespan of C. elegans increased by 24.89% (P < 0.01). Also, SC-RP prolonged the healthspan of the nematode, including reducing lipofuscin levels, improving mobility and enhancing resistance to oxidative stress and heat shock. Moreover, superoxide dismutase and catalase activities were increased for SC-RP treated C. elegans. Meantime the intracellular levels of thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) were attenuated. Express levels of eight genes including daf-2, daf-16, sod-3, skn-1, gst-4, clk-1, age-1 and mev-1 were analyzed by RT-PCR method for possible C. elegan anti-aging mechanisms of SC-RP. Expression levels of key genes daf-2, gst-4 and sod-3 were up-regulated, while that of daf-16, skn-1, and clk-1 were down-regulated. The results suggest that SC-RP could extend the lifespan and healthspan of C. elegans significantly, and the IIS pathway, SKN-1/Nrf2 pathway and mitochondrial metabolism pathway were primarily considered associated. Thus, SC-RP is a potential component to improve aging and aging-related symptoms as new functional materials.

Elevated activity of superoxide dismutase in male late-life schizophrenia and its correlation with clinical symptoms and cognitive deficits

BACKGROUND

Despite inconsistent findings, accumulative evidence has shown abnormalities of the key antioxidant enzyme, superoxide dismutase (SOD), in patients with schizophrenia. However, few studies explored SOD in late-life schizophrenia (LLS). Our work aimed to investigate changes in SOD activity and the relationship between SOD activity and psychotic symptoms or cognitive deficits in LLS.

METHODS

32 geriatric male patients with schizophrenia (age ≥ 60) and 28 age-matched male normal controls were recruited in the study. We assessed cognitive functions with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), evaluated the severity of clinical symptoms with the Positive and Negative Syndrome Scale (PANSS), and measured the plasma levels of SOD.

RESULTS

Patients with LLS presented with higher total levels of SOD compared to the controls (81.70 vs. 65.26 U/ml, p < .001). Except for the visuospatial index, the cognitive performance was significantly worse on RBANS total and other domain scores in the schizophrenia group than the control group. In the schizophrenia group, SOD levels were positively correlated with subscores of general psychopathology and negative symptoms and total scores of the PANSS (all p < .05), and inversely associated with performance in immediate memory, language, and RBANS total scores (all p < .05).

CONCLUSIONS

Our findings suggest that patients with LLS display disturbances in the antioxidant system, which may underlie the pathological process of cognitive impairments and negative symptoms in the late stage of schizophrenia. Supplementing with antioxidants could be a potential treatment.

A review on pharmacological activities and synergistic effect of quercetin with small molecule agents

BACKGROUND

Quercetin is a natural flavonoid, which widely exists in nature, such as tea, coffee, apples, and onions. Numerous studies have showed that quercetin has multiple biological activities such as anti-oxidation, anti-inflammatory, and anti-aging. Hence, quercetin has a significant therapeutic effect on cancers, obesity, diabetes, and other diseases. In the past decades, a large number of studies have shown that quercetin combined with other agents can significantly improve the overall therapeutic effect, compared to single use.

PURPOSE

This work reviews the pharmacological activities of quercetin and its derivatives. In addition, this work also summarizes both in vivo and in vitro experimental evidence for the synergistic effect of quercetin against cancers and metabolic diseases.

METHODS

An extensive systematic search for pharmacological activities and synergistic effect of quercetin was performed considering all the relevant literatures published until August 2021 through the databases including NCBI PubMed, Scopus, Web of Science, and Google Scholar. The relevant literatures were extracted from the databases with following keyword combinations: "pharmacological activities" OR "biological activities" OR "synergistic effect" OR "combined" OR "combination" AND "quercetin" as well as free-text words.

RESULTS

Quercetin and its derivatives possess multiple pharmacological activities including anti-cancer, anti-oxidant, anti-inflammatory, anti-cardiovascular, anti-aging, and neuroprotective activities. In addition, the synergistic effect of quercetin with small molecule agents against cancers and metabolic diseases has also been confirmed.

CONCLUSION

Quercetin cooperates with agents to improve the therapeutic effect by regulating signal molecules and blocking cell cycle. Synergistic therapy can reduce the dose of agents and avoid the possible toxic and side effects in the treatment process. Although quercetin treatment has some potential side effects, it is safe under the expected use conditions. Hence, quercetin has application value and potential strength as a clinical drug. Furthermore, quercetin, as the main effective therapeutic ingredient in traditional Chinese medicine, may effectively treat and prevent coronavirus disease 2019 (COVID-19).

Influence of formic acid treatment on the proteome of the ectoparasite Varroa destructor

The ectoparasite Varroa destructor Anderson and Trueman is the most important parasites of the western honey bee, Apis mellifera L. The most widely currently used treatment uses formic acid (FA), but the understanding of its effects on V. destructor is limited. In order to understand the mechanism of action of FA, its effect on Varroa mites was investigated using proteomic analysis by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). V. destructor was collected from honey bee colonies with natural mite infestation before and 24 h after the initiation of FA treatment and subjected to proteome analysis. A total of 2637 proteins were identified. Quantitative analysis of differentially expressed candidate proteins (fold change ≥ 1.5; p ≤ 0.05) revealed 205 differentially expressed proteins: 91 were induced and 114 repressed in the FA-treated group compared to the untreated control group. Impaired protein synthesis accompanied by increased protein and amino acid degradation suggest an imbalance in proteostasis. Signs of oxidative stress included significant dysregulation of candidate proteins of mitochondrial cellular respiration, increased endocytosis, and induction of heat shock proteins. Furthermore, an increased concentration of several candidate proteins associated with detoxification was observed. These results suggest dysregulated cellular respiration triggered by FA treatment as well as an increase in cellular defense mechanisms, including induced heat shock proteins and detoxification enzymes.

Potential of Telomerase in Age-Related Macular Degeneration-Involvement of Senescence, DNA Damage Response and Autophagy and a Key Role of PGC-1α

Age-related macular degeneration (AMD), the main cause of vision loss in the elderly, is associated with oxidation in the retina cells promoting telomere attrition. Activation of telomerase was reported to improve macular functions in AMD patients. The catalytic subunit of human telomerase (hTERT) may directly interact with proteins important for senescence, DNA damage response, and autophagy, which are impaired in AMD. hTERT interaction with mTORC1 (mTOR (mechanistic target of rapamycin) complex 1) and PINK1 (PTEN-induced kinase 1) activates macroautophagy and mitophagy, respectively, and removes cellular debris accumulated over AMD progression. Ectopic expression of telomerase in retinal pigment epithelium (RPE) cells lengthened telomeres, reduced senescence, and extended their lifespan. These effects provide evidence for the potential of telomerase in AMD therapy. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) may be involved in AMD pathogenesis through decreasing oxidative stress and senescence, regulation of vascular endothelial growth factor (VEGF), and improving autophagy. PGC-1α and TERT form an inhibitory positive feedback loop. In conclusion, telomerase activation and its ectopic expression in RPE cells, as well as controlled clinical trials on the effects of telomerase activation in AMD patients, are justified and should be assisted by PGC-1α modulators to increase the therapeutic potential of telomerase in AMD.

Rhodiola extract promotes longevity and stress resistance of Caenorhabditis elegans via DAF-16 and SKN-1

The effects of Rhodiola extract (RE) on longevity and stress resistance in Caenorhabditis elegans (C. elegans), and the underlying molecular mechanisms were explored in the present study. Results showed that the lifespan of C. elegans was remarkably prolonged by 37.1% after treated with high-dose RE (480 μg mL^-1). Intervention with RE alleviated aging-related declines in the C. elegans model, and enhanced the stress resistance against heat shock, ultraviolet radiation and paraquat. Moreover, RE reduced the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and increased the activities of superoxide dismutase (SOD) and catalase (CAT). RE also upregulated the gene expression of sod-3, gst-4, daf-16, skn-1 in C. elegans, downregulated the gene expression of daf-2 and age-1, and accelerated the translocation of DAF-16 and SKN-1 into the nucleus. Furthermore, the daf-16(mu86) and skn-1(zu169) mutants reversed the extension of lifespan triggered by RE, indicating that these genes were involved in RE-regulated longevity. These results demonstrated that RE could enhance lifespan extension, healthspan and stress resistance of C. elegans via insulin/IGF signaling and SKN-1 pathways. Therefore, the present findings suggested Rhodiola as a potential candidate to ameliorate the symptoms of aging.

Response of the critically endangered Przewalski's gazelle (Procapra przewalskii) to selenium deprived environment

Selenium (Se) is an essential mineral nutrient for animals. Se deprivation can lead to many disorders and even death. This study investigated the response of Przewalski's gazelle (P. przewalskii) to Se-deprived environment. We found that Se deprivation in soil and forage not only influenced the mineral contents of the blood and hair in P. przewalskii, but also severely disrupted their blood parameters. We identified significant changes in the abundance of 146 proteins and 25 metabolites (P < 0.05) in serum, including the selenoproteins L8IG93 (glutathione peroxidase) and F4YD09 (Cu/Zn superoxide dismutase). Furthermore, the major known proteins and metabolites associated with the Se stress response in P. przewalskii were Cu/Zn superoxide dismutase, the vitamin K-dependent protein C, the C4b-binding protein alpha chain, complement component C7, lipase linoleic acid, peptidase D, thymidine, pseudo-uridine, L-phenylalanine, L-glutamine, PGA1, and 15-deoxy-delta-12,14-PGJ2. The main signaling pathways involved included complement and coagulation cascades, metabolic pathways, and stress granule formation. Our results indicate that the intake of Se-deficient forage elicited an oxidative stress response in P. przewalskii. These findings provide insights into the response mechanisms of this threatened gazelle to Se stress, and enable the development of conservation strategies to protect populations on the Qinghai-Tibetan Plateau. SIGNIFICANCE: This study is the first to point out the presence of oxidative stress in P. przewalskii in selenium-deficient areas through proteomics and metabolomics studies. These findings should prove helpful for conservation efforts aimed at P. przewalskii populations and maintenance of the integrity of their ecological environment.

Sleep deprivation induces oxidative stress in the liver and pancreas in young and aging rats

The aging process is characterized by a gradual impairment generally caused by oxidative stress and, more specifically, sleep deprivation, which induces oxidative stress in the brain. The objective of this study was to assess the effect of three types of paradoxical sleep deprivation (PSD): 96 h of PSD (96PSD group); 192 h of PSD (192PSD group); 192 h of PSD followed by a recovery period of 20 days (192PSD + Recovery group) on an oral glucose tolerance test (OGTT), lipid peroxidation (LPO), and superoxide dismutase (SOD) and catalase (CAT) activities in the liver and pancreas of young (3-month-old) and adult (14-month-old) rats. The 96PSD and 192PSD groups of young rats showed lower glucose levels on the OGTT than the control group. In the adult rats, only the 96PSD group had lower glucose levels than the control group. However, the areas under the curve for the young and adult 192 and 192PSD + Recovery groups showed significant differences. Both LPO and SOD increased in the 192PSD and 192PSD + Recovery groups, but CAT decreased in the liver of young rats in the 192PSD group. Regarding the pancreas, LPO and SOD levels increased after 96 h of PSD. In adult animals, CAT decreased in the liver after 96 and 192 h of PSD, while LPO and SOD increased in the pancreas of the 192PSD and PSD + Recovery groups. Differences in the SOD and CAT activities in the liver and SOD activities in the pancreas were also observed between the young and adult rats and maintained across all the PSD groups. In conclusion, PSD induced differential responses that appeared to depend on the duration of the induced condition, the animals’ age, and the tissue analyzed. It was found that adult rats were more susceptible to the effects of PSD than young rats.

The Physiological Conundrum That is the Domestic Dog

Across Mammalia, body size and lifespan are positively correlated. However, in domestic dogs, the opposite is true: small dogs have longer lives compared with large dogs. Here, I present literature-based data on life-history traits that may affect dog lifespan, including adaptations at the whole-organism, and organ-level. Then, I compare those same traits to wild canids. Because oxidative stress is a byproduct of aerobic metabolism, I also present data on oxidative stress in dogs that suggests that small breed dogs accumulate significantly more circulating lipid peroxidation damage compared with large breed dogs, in opposition to lifespan predictions. Further, wild canids have increased antioxidant concentrations compared with domestic dogs, which may aid in explaining why wild canids have longer lifespans than similar-sized domestic dogs. At the cellular level, I describe mechanisms that differ across size classes of dogs, including increases in aerobic metabolism with age, and increases in glycolytic metabolic rates in large breed dogs across their lifespan. To address potential interventions to extend lifespan in domestic dogs, I describe experimental alterations to cellular architecture to test the "membrane pacemaker" hypotheses of metabolism and aging. This hypothesis suggests that increased lipid unsaturation and polyunsaturated fatty acids in cell membranes can increase cellular metabolic rates and oxidative damage, leading to potential decreased longevity. I also discuss cellular metabolic changes of primary fibroblast cells isolated from domestic dogs as they are treated with commercially available drugs that are linked to lifespan and health span expansion.

Therapeutic nanostructures and nanotoxicity

Nanotechnology, with its continuous advancement, leads to the development of nanoscale-level therapeutics to mitigate many complex diseases. This results in the emergence of numerous novel nanomaterials and its composite products into the market such as liposome, polymeric nanoparticles, dendrimers, and nanostructured lipid carrier. However, their application is always determined by a high benefit to risk ratio. Very few research have been done on the toxicity assessment of nanoparticles in the biological system; therefore, the limited knowledge regarding the toxicity profile of nanotherapeutics is available leading to the ignorance of its side effects. Nanoparticles can distribute in the whole body through translocating in the bloodstream by crossing membrane barriers efficiently and shows effect in organs and tissues at cellular and molecular levels. The interaction of nanoparticle with cell may consequences into nanotoxicity. The narrow size distribution, large surface area to mass ratio and surface properties of nanoparticle are significantly associated with nanotoxicity. Nanoparticles can enter into the tissue and cell by invading the membranes and cause cellular injury as well as toxicity. Therefore, the exploration of mechanisms of nanotoxicity has prime importance now a day. The toxicity assessment should be an integral part of the development of nanotherapeutics using various toxicity evaluation models. This review has focused on the exploration of different nanostructures for therapeutic delivery system along with its physicochemical characteristics responsible for adverse effects on human biology, various toxicity evaluation models, and environmental and regulatory hurdles.

Is mitochondrial reactive oxygen species production proportional to oxygen consumption? A theoretical consideration

It has been assumed that at the whole organismal level, the mitochondrial reactive oxygen species (ROS) production is proportional to the oxygen consumption. Recently, a number of researchers have challenged this assumption, based on the observation that the ROS production per unit oxygen consumed in the resting state of mitochondrial respiration is much higher than that in the active state. Here, we develop a simple model to investigate the validity of the assumption and the challenge of it. The model highlights the significance of the time budget that mitochondria operate in the different respiration states. The model suggests that under three physiologically possible conditions, the difference in ROS production per unit oxygen consumed between the respiration states does not upset the proportionality between the whole animal ROS production and oxygen consumption. The model also shows that mitochondrial uncoupling generally enhances the proportionality.

Assessing the influence of curcumin in sex-specific oxidative stress, survival and behavior in Drosophila melanogaster

Oxidative stress, which occurs from an imbalance of reactive oxygen and nitrogen species (RONS) and both endogenous and exogenous antioxidants, promotes aging and underlies sex-specific differences in longevity and susceptibility to age-related neurodegeneration. Recent evidence suggests that curcumin, a yellow pigment derived from turmeric and shown to exhibit antioxidant properties as a RONS scavenger, influences the regulation of genetic elements in endogenous antioxidant pathways. To investigate the role of curcumin in sex-specific in vivo responses to oxidative stress, Drosophila were reared on media supplemented with 0.25, 2.5 or 25 mmol l-1 curcuminoids (consisting of curcumin, demethoxycurcumin and bisdemethoxycurcumin) and resistance to oxidative stress and neural parameters were assessed. High levels of curcuminoids exhibited two sex-specific effects: protection from hydrogen peroxide as an oxidative stressor and alterations in turning rate in an open field. Taken together, these results suggest that the influence of curcuminoids as antioxidants probably relies on changes in gene expression and that sexual dimorphism exists in the in vivo response to curcuminoids.

Phenolic Content, Antioxidant Activity, Anti-Inflammatory Potential, and Acute Toxicity Study of Thymus leptobotrys Murb. Extracts

Thymus leptobotrys is a medicinal plant belonging to the Lamiaceae family, endemic in Morocco, and used in traditional medicine. The present work aims to study the phenolic compounds, the antioxidant activity, the anti-inflammatory effect, and the toxicity of two ethanolic and methanolic extracts of Thymus leptobotrys aerial part. The yield of the methanolic extraction (22.2%) is higher than that of the ethanolic extraction (15.8%) and is characterized by higher contents of polyphenols 243.08 mg/g GAE (mg/g of gallic acid), flavonoids 179.28 mg/g RE (mg/g of rutin), and tannins 39.31 mg/g CE (mg/g of catechin). The in vitro measurement of antioxidant activity with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical reduction test and Trolox equivalent antioxidant capacity (TEAC) test demonstrates the higher performance of the methanolic extract. The evaluation of the anti-inflammatory effect in vivo on adult Wistar female rats leads to a very significant decrease in the inflammation of the edema compared to the standard drug (indomethacin) and the control group. The toxicity test reveals that both extracts showed no toxicity within an LD50 above 2000 mg/kg body weight of the rats.

Predictive and reactive changes in antioxidant defence system in a heterothermic rodent

Living in a seasonal environment requires periodic changes in animal physiology, morphology and behaviour. Winter phenotype of small mammals living in Temperate and Boreal Zones may differ considerably from summer one in multiple traits that enhance energy conservation or diminish energy loss. However, there is a considerable variation in the development of winter phenotype among individuals in a population and some, representing the non-responding phenotype (non-responders), are insensitive to shortening days and maintain summer phenotype throughout a year. Differences in energy management associated with the development of different winter phenotypes should be accompanied by changes in antioxidant defence capacity, leading to effective protection against oxidative stress resulting from increased heat production in winter. To test it, we analysed correlation of winter phenotypes of Siberian hamsters (Phodopus sungorus) with facultative non-shivering thermogenesis capacity (NST) and oxidative status. We found that in both phenotypes acclimation to winter-like conditions increased NST capacity and improved antioxidant defence resulting in lower oxidative stress (OS) than in summer, and females had always lower OS than males. Although NST capacity did not correlate with the intensity of OS, shortly after NST induction responders had lower OS than non-responders suggesting more effective mechanisms protecting from detrimental effects of reactive oxygen metabolites generated during rewarming from torpor. We suggest that seasonal increase in antioxidant defence is programmed endogenously to predictively prevent oxidative stress in winter. At the same time reactive upregulation of antioxidant defence protects against reactive oxygen species generated during NST itself. It suggests that evolution of winter phenotype with potentially harmful characteristics was counterbalanced by the development of protective mechanisms allowing for the maintenance of phenotypic adjustments to seasonally changing environment.

Lifespan of long-lived growth hormone receptor knockout mice was not normalized by housing at 30°C since weaning

Growth hormone receptor knockout (GHRKO) mice are remarkably long-lived and have improved glucose homeostasis along with altered energy metabolism which manifests through decreased respiratory quotient (RQ) and increased oxygen consumption (VO2 ). Short-term exposure of these animals to increased environmental temperature (eT) at 30°C can normalize their VO2 and RQ. We hypothesized that increased heat loss in the diminutive GHRKO mice housed at 23°C and the consequent metabolic adjustments to meet the increased energy demand for thermogenesis may promote extension of longevity, and preventing these adjustments by chronic exposure to increased eT will reduce or eliminate their longevity advantage. To test these hypotheses, GHRKO mice were housed at increased eT (30°C) since weaning. Here, we report that contrasting with the effects of short-term exposure of adult GHRKO mice to 30°C, transferring juvenile GHRKO mice to chronic housing at 30°C did not normalize the examined parameters of energy metabolism and glucose homeostasis. Moreover, despite decreased expression levels of thermogenic genes in brown adipose tissue (BAT) and elevated core body temperature, the lifespan of male GHRKO mice was not reduced, while the lifespan of female GHRKO mice was increased, along with improved glucose homeostasis. The results indicate that GHRKO mice have intrinsic features that help maintain their delayed, healthy aging, and extended longevity at both 23°C and 30°C.

Study of Nutritional and Organoleptic Quality of Formulated Juices from Jujube (Ziziphus lotus L.) and Dates (Phoenix dactylifera L.) Fruits

The present work aims to elaborate many juice formulas (F1 to F8) from two dried fruits (jujubes: Ziziphus lotus L. and dates: Phoenix dactylifera L.). Physicochemical and biochemical characterization of the formula juices shows that juices rich in dates fruits (F1, F3, F5, and F7) are loaded, on average, in total sugars (129.5 g/l), proteins (3.02 g/l), lipids (1.08 g/l), and carotenoid (0.02 mg/l), while juices rich in jujube fruits (F2, F4, F6, and F8) are overloaded, on average, in phenolic compounds (697 mg/l), flavonoids (6.32 mg/l), condensed tannins (2.1 mg/l), hydrolysable tannins (359.5 mg/l), and viscosity (1.062 mm 10–3 s). All formulations developed have a pH that rotates between 5.12 and 5.20. Total antioxidant capacity (CAT) reveals that formulations F1, F3, F5, and F7 show a strong activity compared to the other formulas. The DPPH test shows that all formulated juices have the same antioxidant profile with IC₅₀ values lower than the template (BHT and Vit C). The FRAP test reveals that F2, F4, F6, and F8 formulas have a strong reducing power. Organoleptic evaluation by a jury shows that F4 formula is the best in terms of odor, aroma, and aftertaste agreeability.

Accumulation and trafficking of zinc oxide nanoparticles in an invertebrate model, Bombyx mori, with insights on their effects on immuno-competent cells

Zinc oxide nanoparticles (ZnO NPs) are used in many applications; however, their interactions with cells, immune cells in particular, and potential health risk(s) are not fully known. In this manuscript, we have demonstrated the potential of ZnO NPs to cross the gut barrier in an invertebrate model, Bombyx mori, and that they can reach the hemolymph where they interact with and/or are taken up by immune-competent cells resulting in various toxic responses like decline in hemocyte viability, ROS generation, morphological alterations, apoptotic cell death, etc. Exposure to these NPs also resulted in alteration of hemocyte dynamics including an immediate increase in THC, possibly due to the release of these hemocytes either from enhanced rate of cell divisions or from attached hemocyte populations, and decline in percentage of prohemocytes and increase in percentage of two professional phagocytes, i.e., granulocytes and plasmatocytes, possibly due to the differentiation of prohemocytes into phagocytes in response to a perceived immune challenge posed by these NPs. Taken together, our data suggest that ZnO NPs have the potential to cross gut barrier and cause various toxic effects that could reverse and the insects could return to normal physiological states as there is restoration and repair of various systems and their affected pathways following the clearance of these NPs from the insect body. Our study also indicates that B. mori has the potential to serve as an effective alternate animal model for biosafety, environmental monitoring and screening of NPs, particularly to evaluate their interactions with invertebrate immune system.

Hypotaurine promotes longevity and stress tolerance via the stress response factors DAF-16/FOXO and SKN-1/NRF2 in Caenorhabditis elegans

Hypotaurine, an important sulfur-containing and nonpeptidic amino acid, is a precursor of taurine and an antioxidant.

An infection of Enterobacter ludwigii affects development and causes age-dependent neurodegeneration in Drosophila melanogaster

The effects of teeth-blackening bacteria Enterobacter ludwigii on the physiological system were investigated using the model organism Drosophila melanogaster. The bacteria were mixed with the fly food, and its effect was checked on the growth, development and behaviour of Drosophila. Microbes generate reactive oxygen species (ROS) within the haemolymph of the larvae once it enters into the body. The increased amount of ROS was evidenced by the NBT assay and using 2',7'-dichlorofluorescin diacetate dye, which indicates the mitochondrial ROS. The increased amount of ROS resulted in a number of abnormal nuclei within the gut. Besides that larvae walking became sluggish in comparison with wild type although the larvae crawling path did not change much. Flies hatched from the infectious larvae have the posterior scutellar bristle absent from the thorax and abnormal mechanosensory hairs in the eye, and they undergo time-dependent neurodegeneration as evidenced by the geotrophic and phototrophic assays. To decipher the mechanism of neurodegeneration, flies were checked for the presence of four important bioamines: tyramine, cadaverine, putrescine and histamine. Out of these four, histamine was found to be absent in infected flies. Histamine is a key molecule required for the functioning of the photoreceptor as well as mechanoreceptors. The mechanism via which mouth infectious bacteria E. ludwigii can affect the development and cause age-dependent neurodegeneration is explained in this paper.

Age-Associated Impairments in Mitochondrial ADP Sensitivity Contribute to Redox Stress in Senescent Human Skeletal Muscle

It remains unknown if mitochondrial bioenergetics are altered with aging in humans. We established an in vitro method to simultaneously determine mitochondrial respiration and H₂O₂ emission in skeletal muscle tissue across a range of biologically relevant ADP concentrations. Using this approach, we provide evidence that, although the capacity for mitochondrial H₂O₂ emission is not increased with aging, mitochondrial ADP sensitivity is impaired. This resulted in an increase in mitochondrial H₂O₂ and the fraction of electron leak to H₂O₂, in the presence of virtually all ADP concentrations examined. Moreover, although prolonged resistance training in older individuals increased muscle mass, strength, and maximal mitochondrial respiration, exercise training did not alter H₂O₂ emission rates in the presence of ADP, the fraction of electron leak to H₂O₂, or the redox state of the muscle. These data establish that a reduction in mitochondrial ADP sensitivity increases mitochondrial H₂O₂ emission and contributes to age-associated redox stress.

Diverse functions of DNA glycosylases processing oxidative base lesions in brain

Endogenous and exogenous oxidative agents continuously damage genomic DNA, with the brain being particularly vulnerable. Thus, preserving genomic integrity is key for brain health and neuronal function. Accumulation of DNA damage is one of the causative factors of ageing and increases the risk of a wide range of neurological disorders. Base excision repair is the major pathway for removal of oxidized bases in the genome and initiated by DNA glycosylases. Emerging evidence suggest that DNA glycosylases have non-canonical functions important for genome regulation. Understanding canonical and non-canonical functions of DNA glycosylases processing oxidative base lesions modulating brain function will be crucial for the development of novel therapeutic strategies.

Enrofloxacin and Roundup® interactive effects on the aquatic macrophyte Elodea canadensis physiology

The co-occurrence of aquatic contaminants, such as antibiotics and herbicides, has motivated investigations into their interactive effects on aquatic organisms. We examined the combined effects of environmental concentrations of the antibiotic Enrofloxacin (Enro; 0-2.25 μg l-1) and Roundup OriginalDI (Roundup®; 0-0.75 μg active ingredient l-1), a glyphosate based-herbicide, on Elodea canadensis. Enro alone was not toxic, but the plants were highly sensitive to Roundup® whose toxicity is related to the induction of oxidative stress. The metabolism of Enro by plants into Ciprofloxacin (Cipro) was observed, and although former is not phytotoxic, oxidative events associated with Cipro generation were observed. The activity of cytochrome P450 was shown to be involved in Enro degradation in E. canadensis. As a cytochrome P450 inhibitor, Roundup® decreases Enro metabolism in plants. Enro, in turn, increases glyphosate uptake and toxicity, so that Enro and Roundup® have synergistic effects, disrupting the physiological processes of E. canadensis. Our results suggest E. canadensis as a potential candidate for the reclamation of Enro in contaminated waters, but not for Roundup® due to its high sensitivity to that herbicide.

CoQ10 and Aging

The aging process includes impairment in mitochondrial function, a reduction in anti-oxidant activity, and an increase in oxidative stress, marked by an increase in reactive oxygen species (ROS) production. Oxidative damage to macromolecules including DNA and electron transport proteins likely increases ROS production resulting in further damage. This oxidative theory of cell aging is supported by the fact that diseases associated with the aging process are marked by increased oxidative stress. Coenzyme Q10 (CoQ₁₀) levels fall with aging in the human but this is not seen in all species or all tissues. It is unknown whether lower CoQ₁₀ levels have a part to play in aging and disease or whether it is an inconsequential cellular response to aging. Despite the current lay public interest in supplementing with CoQ₁₀, there is currently not enough evidence to recommend CoQ₁₀ supplementation as an anti-aging anti-oxidant therapy.

NF-κB as the mediator of metformin's effect on ageing and ageing-related diseases

Ageing can be defined as the progressive failure of repair and maintenance systems with a consequent accumulation of cellular damage in nucleic acids, proteins, and lipids. These various types of damage promote ageing by driving cellular senescence and apoptosis. The nuclear factor-kappa B (NF-kB) pathway is one of the key mediators of ageing and this pathway is activated by genotoxic, oxidative and inflammatory stress, and regulates expression of cytokines, growth factors, and genes that regulate apoptosis, cell-cycle progression, and inflammation. Therefore, NF-kB is increased in a variety of tissues with ageing, thus the inhibition of NF-kB leads to delayed onset of ageing-related symptoms and pathologies such as diabetes, atherosclerosis, and cancer. Metformin is often used as an anti-diabetic medication in type 2 diabetes throughout the world and appears to be a potential anti-ageing agent. Owing to its antioxidant, anticancer, cardio-protective and anti-inflammatory properties, metformin has become a potential candidate drug, improving in the context of ageing and ageing-related diseases. An inappropriate NF-kB activation is associated with diseases and pathologic conditions which can impair the activity of genes involved in cell senescence, apoptosis, immunity, and inflammation. Metformin, inhibiting the expression of NF-kB gene, eliminates the susceptibility to common diseases. This review underlines the pleiotropic effects of metformin in ageing and different ageing-related diseases and attributes its effects to the modulation of NF-kB.

"The Same Thing That Makes You Live Can Kill You in the End": Exploring the Effects of Growth Rates and Longevity on Cellular Metabolic Rates and Oxidative Stress in Mammals and Birds

All aerobic organisms are subjected to metabolic by-products known as reactive species (RS). RS can wreak havoc on macromolecules by structurally altering proteins and inducing mutations in DNA, among other deleterious effects. To combat accumulating damage, organisms have an antioxidant system to sequester RS before they cause cellular damage. The balance between RS production, antioxidant defences, and accumulated cellular damage is termed oxidative stress. Physiological ecologists, gerontologists, and metabolic biochemists have turned their attention to whether oxidative stress is the principal, generalized mechanism that mediates and limits longevity, growth rates, and other life-history trade-offs in animals, as may be the case in mammals and birds. At the crux of this theory lies the regulation and activities of the mitochondria with respect to the organism and its metabolic rate. At the whole-animal level, evolutionary theory suggests that developmental trajectories and growth rates can shape the onset and rate of aging. Mitochondrial function is important for aging since it is the main source of energy in cells, and the main source of RS. Altering oxidative stress levels, either increase in oxidative damage or reduction in antioxidants, has proven to also decrease growth rates, which implies that oxidative stress is a cost of, as well as a constraint on, growth. Yet, in nature, many animals exhibit fast growth rates that lead to higher loads of oxidative stress, which are often linked to shorter lifespans. In this article, I summarize the latest findings on whole-animal life history trade-offs, such as growth rates and longevity, and how these can be affected by mitochondrial cellular metabolism, and oxidative stress.

The Neuronal Overexpression of Gclc in Drosophila melanogaster Induces Life Extension With Longevity-Associated Transcriptomic Changes in the Thorax

Some effects of aging in animals are tissue-specific. In D. melanogaster neuronal overexpression of Gclc increases lifespan and improves certain physiological parameters associated with health benefits such as locomotor activity, circadian rhythmicity, and stress resistance. Our previous transcriptomic analyses of Drosophila heads, primarily composed of neuronal tissue, revealed significant changes in expression levels of genes involved in aging-related signaling pathways (Jak-STAT, MAPK, FOXO, Notch, mTOR, TGF-beta), translation, protein processing in endoplasmic reticulum, proteasomal degradation, glycolysis, oxidative phosphorylation, apoptosis, regulation of circadian rhythms, differentiation of neurons, synaptic plasticity, and transmission. Considering that various tissues age differently and age-related gene expression changes are tissue-specific, we investigated the effects of neuronal Gclc overexpression on gene expression levels in the imago thorax, which is primarily composed of muscles. A total of 58 genes were found to be differentially expressed between thoraces of control and Gclc overexpressing flies. The Gclc level demonstrated associations with expression of genes involved in the circadian rhythmicity, the genes in categories related to the muscle system process and the downregulation of genes involved in proteolysis. Most of the functional categories altered by Gclc overexpression related to metabolism including Drug metabolism, Metabolism of xenobiotics by cytochrome P450, Glutathione metabolism, Starch and sucrose metabolism, Citrate cycle (TCA cycle), One carbon pool by folate. Thus, the transcriptomic changes caused by neuron-specific Gclc overexpression in the thorax were less pronounced than in the head and affected pathways also differed from previous results. Although these pathways don't belong to the canonical longevity pathways, we suggest that they could participate in the delay of aging of Gclc overexpressing flies.

Lipid Unsaturation Properties Govern the Sensitivity of Membranes to Photoinduced Oxidative Stress

Unsaturated lipid oxidation is a fundamental process involved in different aspects of cellular bioenergetics; dysregulation of lipid oxidation is often associated with cell aging and death. To study how lipid oxidation affects membrane biophysics, we used a chlorin photosensitizer to oxidize vesicles of various lipid compositions and degrees of unsaturation in a controlled manner. We observed different shape transitions that can be interpreted as an increase in the area of the targeted membrane followed by a decrease. These area modifications induced by the chemical modification of the membrane upon oxidation were followed in situ by Raman tweezers microspectroscopy. We found that the membrane area increase corresponds to the lipids' peroxidation and is initiated by the delocalization of the targeted double bonds in the tails of the lipids. The subsequent decrease of membrane area can be explained by the formation of cleaved secondary products. As a result of these area changes, we observe vesicle permeabilization after a time lag that is characterized in relation with the level of unsaturation. The evolution of photosensitized vesicle radius was measured and yields an estimation of the mechanical changes of the membrane over oxidation time. The membrane is both weakened and permeabilized by the oxidation. Interestingly, the effect of unsaturation level on the dynamics of vesicles undergoing photooxidation is not trivial and thus carefully discussed. Our findings shed light on the fundamental dynamic mechanisms underlying the oxidation of lipid membranes and highlight the role of unsaturations on their physical and chemical properties.

Dystrophin Deficiency Leads to Genomic Instability in Human Pluripotent Stem Cells via NO Synthase-Induced Oxidative Stress

Recent data on Duchenne muscular dystrophy (DMD) show myocyte progenitor's involvement in the disease pathology often leading to the DMD patient's death. The molecular mechanism underlying stem cell impairment in DMD has not been described. We created dystrophin-deficient human pluripotent stem cell (hPSC) lines by reprogramming cells from two DMD patients, and also by introducing dystrophin mutation into human embryonic stem cells via CRISPR/Cas9. While dystrophin is expressed in healthy hPSC, its deficiency in DMD hPSC lines induces the release of reactive oxygen species (ROS) through dysregulated activity of all three isoforms of nitric oxide synthase (further abrev. as, NOS). NOS-induced ROS release leads to DNA damage and genomic instability in DMD hPSC. We were able to reduce both the ROS release as well as DNA damage to the level of wild-type hPSC by inhibiting NOS activity.

Acute exposure to a commercial formulation of Azoxystrobin alters antioxidant enzymes and elicit damage in the aquatic macrophyte Myriophyllum quitense

Azoxystrobin is a strobilurin of growing concern in aquatic environments because it is the most sold fungicide worldwide, however, the information available about its effect on aquatic non-target organisms is scarce. The objective of the present study was to evaluate potential physiological, biochemical, and genetic effects at environmentally relevant (1-10 μg/L) and elevated (100-500 μg/L) concentrations in the aquatic macrophyte Myriophyllum quitense exposed to the commercial formulation AMISTAR^®. Following an acute 24-h exposure, there were no effects of AMISTAR^® on photosynthetic pigments at any of the concentrations evaluated. Glutathione-S-transferase activity was significantly elevated at 1 and 10 μg/L AZX. Significant decrease of catalase and guaiacol peroxidase activities in plants exposed to 500 μg/L, and to 100 and 500 μg/L, respectively, and an increase in glycolate oxidase activity at 500 μg/L was observed. DNA damage at 100 and 500 μg/L was observed. These data indicate that although environmentally relevant levels of AMISTAR^® did not result cytotoxic, this fungicide was genotoxic, affecting the physiological process of photorespiration and caused oxidative damage at high concentrations. In this sense, it is necessary to explore sub-lethal responses in non-target organisms because some effects could promote further potential long-term biological consequences in a context of repeated pulses of exposure.