Hyperbaric Oxygen Combined with Alginate Oligosaccharide Delay D-gal-induced Liver, Kidney and Spleen Senescence in Mice by Attenuating Oxidative Stress

Objectives Hyperbaric oxygen treatment (HBOT) is an adjuvant therapy progressively applied in the treatment of clinical diseases, and alginate oligosaccharide (AOS) is a natural polysaccharide with excellent antioxidant property. In this study, the effects of HBOT combined with AOS on the senescence on liver, kidney and spleen were investigated in a D-galactose (D-gal) -induced senescent mice model. Results The findings indicated that HBOT combined with AOS could delay D-gal-induced aging of liver, kidney and spleen in mice. Specifically, HBOT combined with AOS improved the daily behavior and organ indices of mice. Biochemical and morphological analyses of all tissues indicated that HBOT combined with AOS markedly decreased the unusual elevation of ALT, AST and CREA induced by D-gal, alleviated pathological injury, and significantly enhanced the capacity of antioxidant defense system of mice, including increaing T-SOD, CAT AND GSH-Px activities and decreasing MDA content . In addition, Western Blot results indicated that HBOT combined with AOS also inhibited the overexpression of aging-related proteins p53 and p16. Conclusions To some extent, these findings suggest that HBOT combined with AOS has significant anti-senescence potential in D-gal-induced senescent mice, and the underlying factors may be correlated with the enhancement of antioxidant defense capacity.

Priming Effect of Exogenous ABA on Heat Stress Tolerance in Rice Seedlings is Associated with the Upregulation of Antioxidative Defense Capability and Heat Shock-Related Genes

Heat stress is a major restrictive factor that suppresses rice production. In this study, we investigated the potential priming effect of exogenous abscisic acid (ABA) on heat tolerance in rice seedlings. Seedlings were pretreated with 10 μM ABA by root drenching for 24 h and then subjected to heat stress conditions of 40 °C day/35 °C night. ABA pretreatment significantly decreased leaf withering by 2.5– 28.5% and chlorophyll loss by 12.8–35.1% induced by heat stress in rice seedlings. ABA application also mitigated cell injury, as shown by lower malondialdehyde (MDA) content, membrane injury and expression of cell death-related genes OsKOD1 , OsCP1 and OsNAC4 , while expression of OsBI1 , a cell death-suppressor gene, was upregulated by ABA pretreatment. Moreover, ABA pretreatment improved antioxidant defense capacity, as shown by an obvious upregulation of ROS-scavenging genes and a decrease in ROS content (O 2 – and H 2 O 2 ) and downregulation of the OsRbohs gene. The application of fluridone, an ABA biosynthesis inhibitor, increased membrane injury and the accumulation of ROS under heat stress. Exogenous potent antioxidants (proanthocyanidins, PC) significantly alleviated leaf withering by decreasing ROS overaccumulation and membrane injury induced by heat stress. In addition, ABA pretreatment significantly superinduced the expression of ABA-responsive genes SalT and OsWsi18 , the ABA biosynthesis genes OsNCED3 and OsNCED4 , and the heat shock-related genes OsHSP23.7 , OsHSP17.7 , OsHSF7 and OsHsfA2a . Taken together, these results suggest that exogenous ABA has a potential priming effect for enhancing heat stress tolerance of rice seedlings mainly by improving antioxidant defense capacity and heat shock-related genes.

Genome-Wide Identification and Transcriptional Expression Analysis of Annexin Genes in Capsicum annuum and Characterization of CaAnn9 in Salt Tolerance

Annexin (Ann) is a polygenic, evolutionarily conserved, calcium-dependent and phospholipid-binding protein family, which plays key roles in plant growth, development, and stress response. However, a comprehensive understanding of CaAnn genes of pepper (Capsicum annuum) at the genome-wide level is limited. Based on the available pepper genomic information, we identified 15 members of the CaAnn gene family. Phylogenetic analysis showed that CaAnn proteins could be categorized into four different orthologous groups. Real time quantitative RT-PCR analysis showed that the CaAnn genes were tissue-specific and were widely expressed in pepper leaves after treatments with cold, salt, and drought, as well as exogenously applied MeJA and ABA. In addition, the function of CaAnn9 was further explored using the virus-induced gene silencing (VIGS) technique. CaAnn9-silenced pepper seedlings were more sensitive to salt stress, reflected by the degradation of chlorophyll, the accumulation of reactive oxygen species (ROS), and the decrease of antioxidant defense capacity. This study provides important information for further study of the role of pepper CaAnn genes and their coding proteins in growth, development, and environmental responses.

Influence of C14 Alkane Stress on Antioxidant Defense Capacity, Mineral Nutrient Elements Accumulation and Cadmium Uptake of Ryegrass

In order to explore the influence of C14 alkane on physiological stress responses, mineral nutrient elements uptake, cadmium (Cd) transfer and uptake characteristics of Lolium perenne L. (ryegrass), a series of pot trials were conducted which included a moderate level of Cd (2.182 mg·kg− 1) without (control) and with five levels of C14 alkane (V/m, 0.1%, 0.2%, 0.5%, 1%, 2%). Biomass and Cd content in the root and shoot, chlorophyll content, antioxidant enzymes activity, mineral nutrient elements in the shoot of ryegrass were determined at the end of the experiment. The results indicated that Cd uptake significantly elevated at 0.1% C14 alkane treatment, then gradually decreased with the increase of C14 alkane concentration. Compared with the control, chlorophyll content was significantly suppressed and malondialdehyde (MDA) concentration obviously increased. Superoxide dismutase (SOD) activity and catalase (CAT) activity significantly increased to prevent the C14 alkane stress. With the increased of C14 alkane, the Mn concentration gradually increased, Mg and Fe significantly decreased. Correlation analysis showed that Mn was positively correlated with SOD (with the exception of 2% treatment) and CAT (p < 0.01), and negatively correlated with Cd uptake (p < 0.01). It implied that the increase of Mn induced by C14 alkane stress was an important reason for the decrease of Cd uptake.

A Critical Review of the Abilities, Determinants, and Possible Molecular Mechanisms of Seaweed Polysaccharides Antioxidants

Oxidative stress induces various cardiovascular, neurodegenerative, and cancer diseases, caused by excess reactive oxygen species (ROS). It is attributed to the lack of sufficient antioxidant defense capacity to eliminate unnecessary ROS. Seaweeds are largely cultivated for their edible and commercial purposes. Excessive proliferation of some seaweeds has occurred in coastal areas, causing environmental and economic disasters, and even threating human health. Removing and disposing of the excess seaweeds are costly and labor-intensive with few rewards. Therefore, improving the value of seaweeds utilizes this resource, but also deals with the accumulated biomass in the environment. Seaweed has been demonstrated to be a great source of polysaccharides antioxidants, which are effective in enhancing the antioxidant system in humans and animals. They have been reported to be a healthful method to prevent and/or reduce oxidative damage. Current studies indicate that they have a good potential for treating various diseases. Polysaccharides, the main components in seaweeds, are commonly used as industrial feedstock. They are readily extracted by aqueous and acetone solutions. This study attempts to review the current researches related to seaweed polysaccharides as an antioxidant. We discuss the main categories, their antioxidant abilities, their determinants, and their possible molecular mechanisms of action. This review proposes possible high-value ways to utilize seaweed resources.

Copper Chlorophyllin Impacts on Growth and Drought Stress Tolerance of Tomato Plants

Plant-based pigments have been used as substances to improve crop yield and quality, but the mechanisms of their action on plant growth and stress tolerance are not well understood. The objective of this study was to investigate effects of two formulations of plant-based copper chlorophyllin (Cu-Chl) with and without synthetic paraffinic oil. These formulations, referred to as B18-0074 and B18-0075, were applied as a soil drench plus foliar or a foliar-only application. We investigated their impact on physiological responses of tomato plants under prolonged drought stress conditions. In addition, we examined photosynthetic impacts associated with the application of Cu-Chl formulations. B18-0074 increased leaf photosynthetic rate (Pn) by 8.8% with soil plus foliar application and 18.6% with foliar application relative to the control under drought stress at day 21. Similarly, B18-0075 increased Pn by 16.9% with soil plus foliar application and 24.6% with foliar application relative to the control under drought stress at day 21. The application of the two Cu-Chl–containing products increased leaf antioxidant enzyme catalase (CAT) and ascorbate peroxidase (APX) activity, as well as glutathione (GSH) content. The two products also increased leaf soluble sugars and proline content, indicating improvement of osmotic adjustment. Soil plus foliar and foliar application only of B18-0075 increased root biomass but did not consistently affect plant shoot growth. The results of this study suggest that application of Cu-Chl in combination with synthetic paraffinic oil may improve photosynthetic function, osmotic adjustment, antioxidant defense capacity, and root growth of tomato plant grown under drought stress conditions.

Relationship of Oxidative Stress as a Link between Diabetes Mellitus and Major Depressive Disorder

Both conditions, major depressive disorder (MDD) and diabetes mellitus (DM) are chronic and disabling diseases that affect a very significant percentage of the world’s population. Studies have been shown that patients with DM are more susceptible to develop depression, when compared to the general population. The opposite also happens; MDD could be a risk factor for DM development. Some mechanisms have been proposed to explain the pathophysiological mechanisms involved with these conditions, such as excess of glucocorticoids, hyperglycemia, insulin resistance, and inflammation. These processes can lead to an increase in damage to biomolecules and a decrease in antioxidant defense capacity, leading to oxidative stress.