Do Dipteryx alata Vogel seedlings recover the quality and the photosynthetic and antioxidant responses in the post-flooding?

Dipteryx alata Vogel is a tree species widely found in Cerrado, settling preferentially in well drained soils. Studies related to ecophysiology of D. alata may contribute to the decision making about using seedlings of this species in projects aimed at the recovery of degraded areas where seasonal flooding happens. This study aimed to assess the effects of flooding on photosynthetic and antioxidant metabolism and quality of D. alata seedlings cultivated or not under flooding during four assessment periods (0, 20, 40, and 60 days), followed by 100 days after the end of each assessment period (0+100, 20+100, 40+100, and 60+100 days), allowing verifying the potential for post-flooding recovery. Flooded plants showed lower photosynthetic efficiency than non-flooded plants, regardless of the periods of exposure. However, this efficiency was recovered in the post-flooding, with values similar to that of the non-flooded seedlings. Moreover, the damage to FV/FM was evidenced by an increase in the period of exposure to flooding, but recovery was also observed at this stage of the photosynthetic metabolism. Seedling quality decreased under flooding, not varying between periods of exposure, but remained lower although the increase observed in the post-flooding period, with no recovery after flooding. The occurrence of hypertrophied lenticels associated with physiological changes and an efficient antioxidant enzyme system might have contributed to the survival and recovery of these seedlings. Thus, this species is sensitive to flooding stress but capable of adjusting and recovering metabolic characteristics at 100 days after the suspension of the water stress, but with no recovery in seedling quality. Thus, we suggested plasticity under the cultivation condition and determined that the time of 100 days is not enough for the complete resumption of growth.

The Potential Role of Curcumin in Modulating the Master Antioxidant Pathway in Diabetic Hypoxia-Induced Complications

Oxidative stress is the leading player in the onset and development of various diseases. The Keap1-Nrf2 pathway is a pivotal antioxidant system that preserves the cells’ redox balance. It decreases inflammation in which the nuclear trans-localization of Nrf2 as a transcription factor promotes various antioxidant responses in cells. Through some other directions and regulatory proteins, this pathway plays a fundamental role in preventing several diseases and reducing their complications. Regulation of the Nrf2 pathway occurs on transcriptional and post-transcriptional levels, and these regulations play a significant role in its activity. There is a subtle correlation between the Nrf2 pathway and the pivotal signaling pathways, including PI3 kinase/AKT/mTOR, NF-κB and HIF-1 factors. This demonstrates its role in the development of various diseases. Curcumin is a yellow polyphenolic compound from Curcuma longa with multiple bioactivities, including antioxidant, anti-inflammatory, anti-tumor, and anti-viral activities. Since hyperglycemia and increased reactive oxygen species (ROS) are the leading causes of common diabetic complications, reducing the generation of ROS can be a fundamental approach to dealing with these complications. Curcumin can be considered a potential treatment option by creating an efficient therapeutic to counteract ROS and reduce its detrimental effects. This review discusses Nrf2 pathway regulation at different levels and its correlation with other important pathways and proteins in the cell involved in the progression of diabetic complications and targeting these pathways by curcumin.

Hydrogen peroxide reduces sensitivity to aluminum in canola?

The objective of this study was to evaluate the effect of aluminum and the mitigating potential of H2O2 on the stress and antioxidant responses in canola (Brassica napus var. oleifera (Moench) Delile) affecting the emergence and initial growth of plants. Canola seeds, cultivar Hyola 61, were treated with different concentrations of H2O2 solution (0.0, 0.075, and 0.15 M), and later sown under different concentrations of aluminum (0.0, 10, 20, and 30 mmolc dm-3). After 20 days of plant emergence, survival and growth characteristics were evaluated. 20, 30, 40, 50, and 60 days after emergence, height, chlorophyll index, chlorophyll a fluorescence, and the activity of superoxide dismutase in the roots were determined. The canola is sensitive to aluminum, and the treatment of seeds with H2O2 0.15 M mitigated the stress caused by the highest dose of aluminum. H2O2 treatment enabled high emergence but did not favor seedling survival or growth. The H2O2 did not increase SOD activity. The chlorophyll a fluorescence characteristics proved the sensitivity of canola to aluminum, but the presence of H2O2 maintained the stability and functionality of photosystem II.

Malathion-resistant Tribolium castaneum has enhanced response to oxidative stress, immunity, and fitness

Many cases of insecticide resistance in insect pests give resulting no-cost strains that retain the resistance genes even in the absence of the toxic stressor. Malathion has been widely used against the red flour beetle, Tribolium castaneum Herbst. in stored products although no longer used. Malathion specific resistance in this pest has provided resistance that is long lasting and widely distributed. To understand this resistance a malathion resistant strain was challenged with a range of stressors including starvation, hyperoxia, malathion and a pathogen and the antioxidant responses and some lifecycle parameters were determined. Adult life span of malathion-specific resistant strain of T. castaneum was significantly shorter than the susceptible. Starvation and/or high oxygen reduced adult life span of both strains. Starving with and without 100% oxygen gave longer lifespan for the resistant strain, but for oxygen alone there was no difference. Under oxygen the proportional survival of the resistant strain to the adult stage was significantly higher, for both larvae and pupae, than the susceptible. The resistant strain when stressed with malathion and/or oxygen significantly increased catalase activity, but the susceptible did not. The resistant strain stressed with Paranosema whitei infection had significantly higher survival compared to the susceptible, and with almost no mortality. The malathion resistant strain of T. castaneum showed greater vigour than the susceptible in most oxidative stress situations and especially where stressors were combined. The induction of the antioxidant enzyme catalase could have helped the resistant strain to withstand oxidative stresses, including insecticidal and importantly those from pathogens. These adaptations, in the absence of insecticide, seem to support the increased immunity of host insects to pathogens seen in other insect species, such as mosquitoes. By increasing the responses to a range of stressors the resistant strain could be considered as having enhanced fitness.

Effects of Single or Combined Administration of Dietary Synbiotic and Sodium Propionate on Humoral Immunity and Oxidative Defense, Digestive Enzymes and Growth Performances of African Cichlid (Labidochromis lividus) Challenged with Aeromonas hydrophila

The aim of the present study was to investigate the potential effects of dietary synbiotic (SYN) (Pediococcus acidilactici + Galactooligosaccharides; 10 g kg−1), sodium propionate (SP; 5, 10 and 20 g kg−1) and a combination of SYN + SP on the growth performance, humoral immunity, antioxidant responses and disease resistance against Aeromonas hydrophila of African cichlid (Labidochromis lividus) fingerlings (0.52 ± 0.05 g) in a feeding trial lasting 63 days. A completely randomized design was run with eight treatments, including 0 (control) and supplemented diets containing SYN + SP (e.g., 10 + 5, 10 + 10, 10 + 20, 0 + 5, 0 + 10, 0 + 20 and 10 + 10). The lowest feed conversion ratio value was observed in fish fed the 5 g kg−1-SP and 10 g kg−1-SYN (p < 0.05). The highest values of protein efficiency ratio and protein productive value were recorded in fish fed the 10 g kg−1-SYN (p < 0.05). Fish fed the 10 g kg−1-SYN diet had the highest activities of immunity (lysozyme, immunoglobulin) and antioxidant responses (glutathione peroxidase and superoxide dismutase) (p < 0.05). After 28 days post-challenge, the highest survival rate (57%) was recorded in the diet containing 10 g kg−1 SYN and 5 g kg−1 SP. The results indicated that the single administration of SYN or combined with SP, especially at the level of 5 g kg−1 of diet, enhanced the survival and growth performances, humoral immune response, antioxidant and digestive enzymes of African cichlid.

Redox Dysregulation in Aging and COPD: Role of NOX Enzymes and Implications for Antioxidant Strategies

With a rapidly growing elderly human population, the incidence of age-related lung diseases such as chronic obstructive pulmonary disease (COPD) continues to rise. It is widely believed that reactive oxygen species (ROS) play an important role in ageing and in age-related disease, and approaches of antioxidant supplementation have been touted as useful strategies to mitigate age-related disease progression, although success of such strategies has been very limited to date. Involvement of ROS in ageing is largely attributed to mitochondrial dysfunction and impaired adaptive antioxidant responses. NADPH oxidase (NOX) enzymes represent an important enzyme family that generates ROS in a regulated fashion for purposes of oxidative host defense and redox-based signalling, however, the associations of NOX enzymes with lung ageing or age-related lung disease have to date only been minimally addressed. The present review will focus on our current understanding of the impact of ageing on NOX biology and its consequences for age-related lung disease, particularly COPD, and will also discuss the implications of altered NOX biology for current and future antioxidant-based strategies aimed at treating these diseases.