Biochar and Chitosan Regulate Antioxidant Defense and Methylglyoxal Detoxification Systems and Enhance Salt Tolerance in Jute (Corchorus olitorius L.)

We investigated the role of biochar and chitosan in mitigating salt stress in jute (Corchorus olitorius L. cv. O-9897) by exposing twenty-day-old seedlings to three doses of salt (50, 100, and 150 mM NaCl). Biochar was pre-mixed with the soil at 2.0 g kg−1 soil, and chitosan-100 was applied through irrigation at 100 mg L−1. Exposure to salt stress notably increased lipid peroxidation, hydrogen peroxide content, superoxide radical levels, electrolyte leakage, lipoxygenase activity, and methylglyoxal content, indicating oxidative damage in the jute plants. Consequently, the salt-stressed plants showed reduced growth, biomass accumulation, and disrupted water balance. A profound increase in proline content was observed in response to salt stress. Biochar and chitosan supplementation significantly mitigated the deleterious effects of salt stress in jute by stimulating both non-enzymatic (e.g., ascorbate and glutathione) and enzymatic (e.g., ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, glutathione reductase superoxide dismutase, catalase, peroxidase, glutathione S-transferase, glutathione peroxidase) antioxidant systems and enhancing glyoxalase enzyme activities (glyoxalase I and glyoxalase II) to ameliorate reactive oxygen species damage and methylglyoxal toxicity, respectively. Biochar and chitosan supplementation increased oxidative stress tolerance and improved the growth and physiology of salt-affected jute plants, while also significantly reducing Na+ accumulation and ionic toxicity and decreasing the Na+/K+ ratio. These findings support a protective role of biochar and chitosan against salt-induced damage in jute plants.

NorA, HmpX, and NorB cooperate to reduce NO toxicity during denitrification and plant pathogenesis in Ralstonia solanacearum

Ralstonia solanacearum, which causes bacterial wilt disease of many crops, needs denitrifying respiration to succeed in hypoxic plant xylem vessels. Inside its host this pathogen confronts toxic oxidative radicals like nitric oxide (NO) generated by both bacterial denitrification and host defenses. R. solanacearum has multiple distinct mechanisms that could mitigate this stress, including Repair of Iron Cluster (RIC) homolog NorA, nitric oxide reductase NorB, and flavohaemoglobin HmpX. R. solanacearum upregulated norA, norB, and hmpX in response to exogenous NO, denitrification, and tomato pathogenesis. Single mutants lacking any of these genes accumulated NO during denitrification and were more susceptible to oxidative stress. Plant defense genes were upregulated in tomatoes infected with the NO-overproducing ΔnorB mutant, suggesting bacterial detoxification of NO reduces pathogen visibility. Expression of many iron and sulfur metabolism genes increased in the ΔnorB, ΔnorA, and ΔhmpX mutants, suggesting that losing even one NO detoxification system demands metabolic compensation. Single mutants suffered only moderate fitness reductions in host plants, possibly because they upregulated their remaining detoxification genes. However, ΔnorA/norB, ΔnorB/hmpX, and ΔnorA/hmpX double mutants grew poorly in denitrifying culture and in planta. Loss of norA, norB, and hmpX may be lethal as the methods used to construct the double mutants did not generate a triple mutant. Aconitase activity assays showed that NorA, HmpX and especially NorB are important for maintaining iron-sulfur cluster proteins. Thus, R. solanacearum's three NO detoxification systems each contribute to and are collectively essential for overcoming oxidative stress during denitrification and growth in a host plant.

Effects of Cu, Zn and Their Mixtures on Bioaccumulation and Antioxidant Enzyme Activities in Galleria Mellonella L. (Lepidoptera: Pyralidae)

The effects of Cu, Zn and their mixture on bioaccumulation and antioxidant enzyme activities of midgut and fat body of Galleria mellonella larvae were investigated. The application of metals as a mixture showed a synergistic effect and the accumulation levels were increased in both tissues. Zn accumulation increased in midgut and fat body of G. mellonella larvae exposed to metal singly. On the other hand, Cu accumulation increased in midgut, while a decrease was observed in fat body exposed to Cu singly. Moreover, it was determined that oxidative stress was occured in midgut and fat body of G. mellonella larvae with significant decreases and increases in antioxidant and detoxification enzyme activities when fed singly and in mixture with different concentrations of Cu and Zn. Understanding the reactions of G. mellonella, which is a model organism showing immune system responses similar to vertebrates and bioindicator species, to metals by detoxification systems, which is an important parameter in insect physiology, is thought to contribute to future toxicological, genotoxic, physiological and ecotoxicological studies. G. mellonella larvae, which were used as a model organism, shows a similar reaction to mammals.

Deletion of Mocos induces xanthinuria with obstructive nephropathy and major metabolic disorders in mice

Background: Xanthinuria type II is a rare autosomal purine disorder. This recessive defect of purine metabolism remains an underrecognized disorder. Methods: Mice with targeted disruption of the molybdenum cofactor sulfurase (Mocos) gene were generated to enable an integrated understanding of purine disorders and evaluate pathophysiological functions of this gene found in large number of pathways and known to be associated with autism. Results: Mocos deficient mice die with 4 weeks of age due to renal failure of distinct obstructive nephropathy with xanthinuria, xanthine deposits, cystic tublular dilatation, Tamm Horsfall (uromodulin) protein deposits, tubular cell necrosis with neutrophils and occasionally hypdronephrosis with urolithiasis. Obstructive nephropathy is associated with moderate interstitial inflammatory and fibrotic responses, anemia, reduced detoxification systems and important alterations of the metabolism of purines, amino acids and phospholipids.Conversely, heterozygous mice expressing reduced MOCOS protein are healthy with no apparent pathology. Conclusions: Mocos deficient mice develop a lethal obstructive nephropathy associated with profound metabolic changes. Studying MOCOS functions may provide important clues about the underlying pathogenesis of xanthinuria and other diseases requiring early diagnosis

Genistein Inhibits Protein Glycation in Healthy and Pre-Obese Mice Treated With High-Fat Diet via Trapping and Activating the Detoxification Pathways of Methylglyoxal

Objectives High levels of methylglyoxal (MGO) and advanced glycation end products (AGEs) play important roles in the pathogenesis of diabetes and other chronic diseases. This study aimed to investigate the underlying mechanisms that dietary genistein inhibits the accumulations of MGO and AGEs in healthy and pre-obese mice treated with high-fat diet. Methods In Study 1, male C57BL/6J mice (6-wk old, n = 15) were fed a low-fat (LF) diet (10% fat energy) or a very-high-fat diet (VHF, 60% fat energy) alone or including 0.25% genistein (VHF-G) for 16 weeks. In study 2, the mice were fed the LF diet (LF) or HF diet alone (HF, 45% fat energy) or in combination with up to 0.2% MGO in water (HFM), and 0.067% (HFM-GL) or 0.2% (HFM-GH) dietary genistein for 18 weeks. In study 3, the mice were induced with obesity after being fed HF diet (45% fat energy) for 9 weeks before being administrated with genistein at two doses of 0.1% (G 0.1) and 0.2% (G 0.2) in the HF diet for additional 19 weeks. The concentrations of MGO and AGEs in mouse samples and other metabolic data of the mice were measured. Moreover, the potential mechanisms of genistein on lowering MGO and AGEs were investigated. Results The plasma MGO concentration in VHF-G mice was 52% lower than that in VHF mice. Also, the AGE levels in plasma, liver, and kidney of VHF-G mice were 73%, 52%, and 49% lower than in the VHF group (Study 1). Similarly, the concentrations of plasma MGO and AGEs in plasma, liver, and kidney of HFM-GH mice were 33.5%, 49%, 69%, and 54% lower than in HFM mice (Study 2). Moreover, dietary genistein at 0.2% (G 0.2) significantly decreased the MGO levels in plasma and liver by 43.9% and 30.4% compared with HF mice and decreased the AGE level in the kidney by 48.3% in pre-obese mice (Study 3). Mechanistically, genistein lowered MGO concentrations and inhibited AGE formation through direct trapping both endogenous and exogenous MGO to form the MGO adducts and activating the MGO detoxification systems of glyoxalase and aldose reductase (AR) to lower MGO levels indirectly in vivo. Conclusions The present studies provide novel insights into the anti-obesity and anti-glycation roles of dietary genistein in mice. However, whether genistein could exert similar beneficial effects in humans needs to be further investigated. Funding Sources USDA/NIFA.

Exposure of Helicoverpa armigera Larvae to Plant Volatile Organic Compounds Induces Cytochrome P450 Monooxygenases and Enhances Larval Tolerance to the Insecticide Methomyl

Plants release an array of volatile chemicals into the air to communicate with other organisms in the environment. Insect attack triggers emission of herbivore-induced plant volatiles (HIPVs). How insect herbivores use these odors to plan their detoxification systems is vital for insect adaptation to environmental xenobiotics. Here we show that the larvae of Helicoverpa armigera (Hübner), a broadly polyphagous lepidopteran herbivore, have the capacity to use plant volatiles as cues to upregulate multiple detoxification systems, including cytochrome P450 monooxygenases (P450s), for detoxification of insecticides. Olfactory exposure of the fifth instars to two terpene volatiles limonene and nerolidol, and two green-leaf volatiles 2-heptanone and cis-3-hexenyl acetate significantly reduced larval susceptibility to the insecticide methomyl. However, larval pretreatment with piperonyl butoxide (PBO), a known P450 inhibitor, neutralized the effects of volatile exposure. Furthermore, larval exposure to the four plant volatiles enhanced activities of P450 enzymes in midguts and fatbodies, and upregulated expression of CYP6B2, CYP6B6 and CYP6B7, P450s involved in detoxification of the insecticide. Larval exposure to 2-heptanone and limonene volatiles also enhanced activities of glutathione-s-transferase and carboxylesterase. Our findings suggest that olfactory exposure to HIPVs enhances larval insecticide tolerance via induction of detoxification P450s.

The Role of Lipoxidation in the Pathogenesis of Diabetic Retinopathy

Lipids can undergo modification as a result of interaction with reactive oxygen species (ROS). For example, lipid peroxidation results in the production of a wide variety of highly reactive aldehyde species which can drive a range of disease-relevant responses in cells and tissues. Such lipid aldehydes react with nucleophilic groups on macromolecules including phospholipids, nucleic acids, and proteins which, in turn, leads to the formation of reversible or irreversible adducts known as advanced lipoxidation end products (ALEs). In the setting of diabetes, lipid peroxidation and ALE formation has been implicated in the pathogenesis of macro- and microvascular complications. As the most common diabetic complication, retinopathy is one of the leading causes of vision loss and blindness worldwide. Herein, we discuss diabetic retinopathy (DR) as a disease entity and review the current knowledge and experimental data supporting a role for lipid peroxidation and ALE formation in the onset and development of this condition. Potential therapeutic approaches to prevent lipid peroxidation and lipoxidation reactions in the diabetic retina are also considered, including the use of antioxidants, lipid aldehyde scavenging agents and pharmacological and gene therapy approaches for boosting endogenous aldehyde detoxification systems. It is concluded that further research in this area could lead to new strategies to halt the progression of DR before irreversible retinal damage and sight-threatening complications occur.

Synergistic quinolone sensitization by targeting recA SOS response gene and oxidative stress

Suppression of recA SOS response gene and reactive oxygen species (ROS) overproduction have been shown, separately, to enhance fluoroquinolone activity and lethality. Their putative synergistic impact as a strategy to potentiate the efficacy of bactericidal antimicrobial agents like fluoroquinolones is unknown. We generated Escherichia coli mutants that exhibited suppressed ΔrecA gene in combination with inactivated ROS detoxification system genes (ΔsodA, ΔsodB, ΔkatG, ΔkatE, ΔahpC) or inactivated oxidative stress regulator genes (ΔoxyR, ΔrpoS) to evaluate the interplay of both DNA repair and detoxification systems in drug response. Synergistic sensitization effects, ranging from 7.5- to 30-fold relative to the wild-type, were observed with ciprofloxacin in double knockouts of recA and inactivated detoxification system genes. Compared to recA knockout, inactivation of an additional detoxification system gene reduced MIC values up to 8-fold. In growth curves, no growth was evident in mutants doubly-deficient for recA gene and oxidative detoxification systems at subinhibitory concentrations of ciprofloxacin, in contrast to the recA-deficient strain. There was a marked reduction of viable bacteria in a short period of time when recA gene and other detoxification system genes (katG, sodA or ahpC) were inactivated (using absolute ciprofloxacin concentrations). At 4 hours, a bactericidal effect of ciprofloxacin was observed for ΔkatG/ΔrecA and ΔahpC/ΔrecA double mutants compared to the single ΔrecA mutant (Δ3.4 Log10 CFU/mL). Synergistic quinolone sensitization, by targeting the recA gene and oxidative detoxification stress systems, reinforces the role of both DNA repair systems and ROS in antibiotic-induced bacterial cell death, opening up a new pathway for antimicrobial sensitization.

Molecules and Mechanisms to Overcome Oxidative Stress Inducing Cardiovascular Disease in Cancer Patients

Reactive oxygen species (ROS) are molecules involved in signal transduction pathways with both beneficial and detrimental effects on human cells. ROS are generated by many cellular processes including mitochondrial respiration, metabolism and enzymatic activities. In physiological conditions, ROS levels are well-balanced by antioxidative detoxification systems. In contrast, in pathological conditions such as cardiovascular, neurological and cancer diseases, ROS production exceeds the antioxidative detoxification capacity of cells, leading to cellular damages and death. In this review, we will first describe the biology and mechanisms of ROS mediated oxidative stress in cardiovascular disease. Second, we will review the role of oxidative stress mediated by oncological treatments in inducing cardiovascular disease. Lastly, we will discuss the strategies that potentially counteract the oxidative stress in order to fight the onset and progression of cardiovascular disease, including that induced by oncological treatments.

Translational control of enzyme scavenger expression with toxin-induced micro RNA switches

Biological computation requires in vivo control of molecular behavior to progress development of autonomous devices. miRNA switches represent excellent, easily engineerable synthetic biology tools to achieve user-defined gene regulation. Here we present the construction of a synthetic network to implement detoxification functionality. We employed a modular design strategy by engineering toxin-induced control of an enzyme scavenger. Our miRNA switch results show moderate synthetic expression control over a biologically active detoxification enzyme molecule, using an established design protocol. However, following a new design approach, we demonstrated an evolutionarily designed miRNA switch to more effectively activate enzyme activity than synthetically designed versions, allowing markedly improved extrinsic user-defined control with a toxin as inducer. Our straightforward new design approach is simple to implement and uses easily accessible web-based databases and prediction tools. The ability to exert control of toxicity demonstrates potential for modular detoxification systems that provide a pathway to new therapeutic and biocomputing applications.