Genetic Polymorphisms of MnSOD Modify the Impacts of Environmental Melamine on Oxidative Stress and Early Kidney Injury in Calcium Urolithiasis Patients

Environmental melamine exposure increases the risks of oxidative stress and early kidney injury. Manganese superoxide dismutase (MnSOD), glutathione peroxidase, and catalase can protect the kidneys against oxidative stress and maintain normal function. We evaluated whether their single-nucleotide polymorphisms (SNPs) could modify melamine’s effects. A total of 302 patients diagnosed with calcium urolithiasis were enrolled. All patients provided one-spot overnight urine samples to measure their melamine levels, urinary biomarkers of oxidative stress and renal tubular injury. Median values were used to dichotomize levels into high and low. Subjects carrying the T allele of rs4880 and high melamine levels had 3.60 times greater risk of high malondialdehyde levels than those carrying the C allele of rs4880 and low melamine levels after adjustment. Subjects carrying the G allele of rs5746136 and high melamine levels had 1.73 times greater risk of high N-Acetyl-β-d-glucosaminidase levels than those carrying the A allele of rs5746136 and low melamine levels. In conclusion, the SNPs of MnSOD, rs4880 and rs5746136, influence the risk of oxidative stress and renal tubular injury, respectively, in calcium urolithiasis patients. In the context of high urinary melamine levels, their effects on oxidative stress and renal tubular injury were further increased.

Cryotrapping peroxide in the active site of human mitochondrial manganese superoxide dismutase crystals for neutron diffraction

Structurally identifying the enzymatic intermediates of redox proteins has been elusive due to difficulty in resolving the H atoms involved in catalysis and the susceptibility of ligand complexes to photoreduction from X-rays. Cryotrapping ligands for neutron protein crystallography combines two powerful tools that offer the advantage of directly identifying hydrogen positions in redox-enzyme intermediates without radiolytic perturbation of metal-containing active sites. However, translating cryogenic techniques from X-ray to neutron crystallography is not straightforward due to the large crystal volumes and long data-collection times. Here, methods have been developed to visualize the evasive peroxo complex of manganese superoxide dismutase (MnSOD) so that all atoms, including H atoms, could be visualized. The subsequent cryocooling and ligand-trapping methods resulted in neutron data collection to 2.30 Å resolution. The P6122 crystal form of MnSOD is challenging because it has some of the largest unit-cell dimensions (a = b = 77.8, c = 236.8 Å) ever studied using high-resolution cryo-neutron crystallography. The resulting neutron diffraction data permitted the visualization of a dioxygen species bound to the MnSOD active-site metal that was indicative of successful cryotrapping.

Effects of Manganese Hydroxychloride on Growth Performance, Antioxidant Capacity, Tibia Parameters and Manganese Deposition of Broilers

This study was conducted to investigate the effects of dietary supplementation with manganese hydroxychloride (MHC) on production performance, antioxidant capacity, tibial quality, and manganese (Mn) deposition of broilers. A total of 756 one-day-old male Arbor Acres broilers were randomly allotted to 7 treatments of 6 replicates with 18 broilers per replicate. Broilers were fed corn-soybean meal basal diets supplemented of 100 mg/kg Mn as Mn sulfate (MnSO4), or 0, 20, 40, 60, 80, 100 mg/kg Mn as MHC for 42 days. The growth performance of broilers was not affected by dietary MnSO4 or MHC (p > 0.05), whereas the dressing percentage increased linearly (p < 0.05) with increasing of dietary MHC addition level. The activities of catalase (CAT) and manganese superoxide dismutase (MnSOD), and total antioxidant capability (T-AOC) in serum and liver on day 42 increased linearly (p < 0.05) with increasing of dietary MHC level, while malondialdehyde (MDA) concentration reduced linearly (p < 0.05). The length, strength, and density index of tibia increased linearly (p < 0.05) on day 21 as MHC supplementation level increased; there were no differences between MnSO4 group and 40–100 mg/kg Mn as MHC groups in tibial parameters of broilers (p > 0.05). As supplemental MHC levels increased, the Mn contents in heart, liver, kidney, and tibia increased linearly on day 42 (p < 0.05). In summary, dietary supplementation with MHC improved antioxidant capacity, bone quality, and Mn contents in broilers, but no effects on growth performance were detected. Based on the results of this study, dietary inclusion of 50–90 mg/kg Mn in the form of MHC to broilers is recommended.

Re-Print- Artificial Respiration in Severe COVID-19 Cases: A Beneficial or Deleterious Treatment

The world over artificial respiration is employed as one of the intensive care treatment measures in severe cases of COVID-19 because of the significant respiratory distress patients develop. Nevertheless, the outcome is poor. Lethality varies from country to country and clinic to clinic between 50% and 90%. So the question arises as to whether the use of oxygen can be a risk factor in the treatment of acute inflammatory diseases in general and of COVID-19 in particular. Oxidative stress is the first and oldest step of cellular defense and starts before the activation of the immune system. This leads to an increase of intracellular oxygen in the mitochondria, followed by an elevated electron flow and the formation of superoxide as well as other reactive oxygen species and reactive nitrogen species. Superoxide reacts with nitric oxide, which is always present in inflammation, forming peroxynitrite, the strongest inducer of oxidative stress. This step induces the activation of nuclear factor kB, followed by the production of proinflammatory cytokines. The elevated levels of inducible nitric oxide synthase keep this cycle running. High amounts of superoxide have to be compensated and catabolized by manganese-superoxide dismutase 2 into hydrogen peroxide and in a second step by catalase into water. When using artificial respiration, these steps are accelerated considerably in the inflamed tissue of the lung, leading to a significant increase of the electron flow as well as an elevation of superoxide, oxidative stress, and water. As SARS-CoV-2 generally induces the production of proteins (and not only those necessary for viral reproduction), the water will remain in the tissue, causing edema and thus a wet lung syndrome associated with a growing oxygen diffusion distance to red blood cells. Ultimately, patients do not suffocate in spite of, but because of, the presence of high levels of oxygen. The limited number of patients who survive this deleterious treatment describe it as having had a sensation of drowning. The reasons will be discussed.

First Report of Colletotrichum tropicale Causing Anthracnose on Common Fig in Taiwan

Ficus carica L. known as common fig is one of the most profitable fruit crops in Taiwan. Their fruit are harvested for high-priced market. Common fig can be eaten fresh or dried and processed to make different food products. In September 2015, an anthracnose-like disease was widely observed on common fig fruit planted in an orchard in Lukang township (24°04'36" N, 120°27'15" E) in Changhua County, central Taiwan. Symptoms were sunken, water-soaked lesions covered with salmon-colored spore masses and were observed on all stages of fruit, especially when fruit was ripe. Four fungal isolates were collected from four diseased fruit of different plants in the same orchard. Conidia were spread on 2% water agar, and a single conidium was separated by a handmade glass needle. Fungal isolates were grown on potato dextrose agar (PDA) at 24 to 28°C with diffused light. All four strains produced white, aerial, and cottony mycelia covered with abundant salmon-colored conidial masses on PDA. The conidia were hyaline, single celled, round cylindrical on both ends, thin walled, and the contents guttulate. The sizes of conidia were 15.4 (18.5 to 13.1) × 4.73 (5.8 to 3.6) μm [average (max. to min.); length/width ratio = 3.25, n = 40]. DNA was isolated from the representative isolate FC1 and used for amplification of partial sequences of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), β-tubulin 2 (TUB2), manganese-superoxide dismutase (SOD2), calmodulin (CAL), chitin synthase 1 (CHS-1) (Weir et al. 2012) and the intergenic region of apn2 and MAT1-2-1 gene (ApMat) genes (Sharma et al. 2013). A BLAST search against the NCBI database revealed that FC1 gene sequences [GenBank accession nos. MT192648 (ITS), MT155819 (GAPDH), MT199873 (ACT), MT199874 (TUB2), MT815916 (SOD2), MT815917 (CAL), MW684717 (CHS-1) and MT221652 (ApMat)] displayed 99.1, 98.2, 99.3, 99.6, 99.5, 100.0, 92.8 and 100.0% nucleotide identity to the respective gene sequences of Colletotrichum tropicale CBS 124949 (ICMP18653) (JX010264, JX010007, JX009489, JX010407, JX010329, JX009719, JX009870 and KC790728). Multilocus phylogenetic analysis performed with reference sequences showed that the isolate FC1 clustered with C. tropicale in accordance with BLAST results. A conidial suspension (1 × 106 conidia/mL) prepared from FC1 isolate was inoculated by spraying onto detached, ripe, healthy, non-wounded and surface-disinfected common fig fruit (cv. China, n = 4). Fruit sprayed with sterile water were used as control. Fruit were kept in a moist chamber (greater than 90% relative humidity, 24 to 28°C) for 24 h and then maintained in the lab for additional 5 days. The inoculated fruit developed lesions similar to the disease symptoms in the orchard. No symptom was observed on fruit treated with water. C. tropicale was re-isolated from symptomatic fruits and had similar morphological characteristics to FC1 isolate, thus fulfilling Koch’s postulates. The experiment was repeated once showing similar results. The FC1 isolate of C. tropicale with the identification number BCRC FU31436 has been deposited at Taiwan Bioresource Collection and Research Center. This fungus had previously been found on lotus and mango in Taiwan (Chen and Kirschner 2018; Wu et al. 2020), while the pathogenicity among the isolates from different origins is not yet known. To our knowledge, this is the first report of C. tropicale causing anthracnose on common fig fruit in Taiwan.

The protective effect of manganese superoxide dismutase from thermophilic bacterium HB27 on hydrochloric acid-induced chemical cystitis in rats

Purpose To evaluate the effects of manganese superoxide dismutase (Mn-SOD) from thermophilic bacterium HB27 (name as Tt-SOD) on chemical cystitis. Methods Control and experimental rats were infused by intravesical saline or hydrochloric acid (HCl) on the first day of the experiments. Saline, sodium hyaluronate (SH) or Tt-SOD were infused intravesically once a day for three consequent days. On the fifth day, the rats were weighted and sacrificed following a pain threshold test. The bladder was harvested for histological and biochemical analyses. Results Tt-SOD could reduce the bladder index, infiltration of inflammatory cells in tissues, serum inflammatory factors and SOD levels, mRNA expression of inflammatory factors in tissues, and increase perineal mechanical pain threshold and serum MDA and ROS levels in HCl-induced chemical cystitis. Furthermore, Tt-SOD alleviated inflammation and oxidative stress by the negative regulation of the NF-κB p65 and p38 MAPK signaling pathway. Conclusions Intravesical instillation of Tt-SOD provides protective effects against HCl-induced cystitis.

Mitochondrial Sirtuin TcSir2rp3 Affects TcSODA Activity and Oxidative Stress Response in Trypanosoma cruzi

Trypanosoma cruzi faces a variety of environmental scenarios during its life cycle, which include changes in the redox environment that requires a fine regulation of a complex antioxidant arsenal of enzymes. Reversible posttranslational modifications, as lysine acetylation, are a fast and economical way for cells to react to environmental conditions. Recently, we found that the main antioxidant enzymes, including the mitochondrial superoxide dismutase A (TcSODA) are acetylated in T. cruzi, suggesting that protein acetylation could participate in the oxidative stress response in T. cruzi. Therefore, we investigated whether mitochondrial lysine deacetylase TcSir2rp3 was involved in the activity control of TcSODA. We observed an increased resistance to hydrogen peroxide and menadione in parasites overexpressing TcSir2rp3. Increased resistance was also found for benznidazole and nifurtimox, known to induce reactive oxidative and nitrosactive species in the parasite, associated to that a reduction in the ROS levels was observed. To better understand the way TcSir2rp3 could contributes to oxidative stress response, we analyzed the expression of TcSODA in the TcSir2rp3 overexpressing parasites and did not detect any increase in protein levels of this enzyme. However, we found that these parasites presented higher levels of superoxide dismutase activity, and also that TcSir2rp3 and TcSODA interacts in vivo. Knowing that TcSODA is acetylated at lysine residues K44 and K97, and that K97 is located at a similar region in the protein structure as K68 in human manganese superoxide dismutase (MnSOD), responsible for regulating MnSOD activity, we generated mutated versions of TcSODA at K44 and K97 and found that replacing K97 by glutamine, which mimics an acetylated lysine, negatively affects the enzyme activity in vitro. By using molecular dynamics approaches, we revealed that acetylation of K97 induces specific conformational changes in TcSODA with respect to hydrogen-bonding pattern to neighbor residues, suggesting a key participation of this residue to modulate the affinity to O2−. Taken together, our results showed for the first time the involvement of lysine acetylation in the maintenance of homeostatic redox state in trypanosomatids, contributing to the understanding of mechanisms used by T. cruzi to progress during the infection.

Bisdemethoxycurcumin Protects Small Intestine from Lipopolysaccharide-Induced Mitochondrial Dysfunction via Activating Mitochondrial Antioxidant Systems and Mitochondrial Biogenesis in Broiler Chickens

Bisdemethoxycurcumin is one of the three curcuminoids of turmeric and exhibits good antioxidant activity in animal models. This study is aimed at investigating the effect of bisdemethoxycurcumin on small intestinal mitochondrial dysfunction in lipopolysaccharide- (LPS-) treated broilers, especially on the mitochondrial thioredoxin 2 system and mitochondrial biogenesis. A total of 320 broiler chickens were randomly assigned into four experimental diets using a 2 × 2 factorial arrangement with diet (0 and 150 mg/kg bisdemethoxycurcumin supplementation) and stress (saline or LPS challenge) for 20 days. Broilers received a dose of LPS (1 mg/kg body weight) or sterile saline intraperitoneally on days 16, 18, and 20 of the trial. Bisdemethoxycurcumin mitigated the mitochondrial dysfunction of jejunum and ileum induced by LPS, as evident by the reduced reactive oxygen species levels and the increased mitochondrial membrane potential. Bisdemethoxycurcumin partially reversed the decrease in the mitochondrial DNA copy number and the depletion of ATP levels. Bisdemethoxycurcumin activated the mitochondrial antioxidant response, including the prevention of lipid peroxidation, enhancement of manganese superoxide dismutase activity, and the upregulation of the mitochondrial glutaredoxin 5 and thioredoxin 2 system. The enhanced mitochondrial respiratory complex activities in jejunum and ileum were also attributed to bisdemethoxycurcumin treatment. In addition, bisdemethoxycurcumin induced mitochondrial biogenesis via transcriptional regulation of proliferator-activated receptor-gamma coactivator-1alpha pathway. In conclusion, our results demonstrated the potential of bisdemethoxycurcumin to attenuate small intestinal mitochondrial dysfunction, which might be mediated via activating the mitochondrial antioxidant system and mitochondrial biogenesis in LPS-treated broilers.

Melatonin Reduces Oxidative Stress in the Right Ventricle of Newborn Sheep Gestated under Chronic Hypoxia

Pulmonary arterial hypertension of newborns (PAHN) constitutes a critical condition involving both severe cardiac remodeling and right ventricle dysfunction. One main cause of this condition is perinatal hypoxia and oxidative stress. Thus, it is a public health concern for populations living above 2500 m and in cases of intrauterine chronic hypoxia in lowlands. Still, pulmonary and cardiac impairments in PAHN lack effective treatments. Previously we have shown the beneficial effects of neonatal melatonin treatment on pulmonary circulation. However, the cardiac effects of this treatment are unknown. In this study, we assessed whether melatonin improves cardiac function and modulates right ventricle (RV) oxidative stress. Ten lambs were gestated, born, and raised at 3600 m. Lambs were divided in two groups. One received daily vehicle as control, and another received daily melatonin (1 mg·kg−1·d−1) for 21 days. Daily cardiovascular measurements were recorded and, at 29 days old, cardiac tissue was collected. Melatonin decreased pulmonary arterial pressure at the end of the experimental period. In addition, melatonin enhanced manganese superoxide dismutase and catalase (CAT) expression, while increasing CAT activity in RV. This was associated with a decrease in superoxide anion generation at the mitochondria and NADPH oxidases in RV. Finally, these effects were associated with a marked decrease of oxidative stress markers in RV. These findings support the cardioprotective effects of an oral administration of melatonin in newborns that suffer from developmental chronic hypoxia.

281 The Effects of Whole Cottonseed Supplementation on Performance, Breeding Soundness Exams, and Manganese Superoxide Dismutase Concentrations in the Blood and Semen of Beef Bulls

The objective of this research was to determine the effects of whole cottonseed containing gossypol on post-pubertal beef bulls. In a two-year study, 46 Angus and Red Angus bulls (body weight 457.0 ± 85.2 kg; 16 to 20-months of age) were stratified by BW and randomly assigned to 1 of 3 levels of whole cottonseed supplementation while receiving ad libitum roughage. The treatments included: DD (n = 14, control; 3.18 kg/d of dried distillers grain, W/D (n = 16; 1.59 kg/d of whole cottonseed and 1.59 kg/d of dried distillers grain), or WW (n = 16 3.18 kg/d of whole cottonseed). Diets were formulated to be isocaloric and isonitrogenous. In both years, bulls were weighed, administered a breeding soundness exam, and morphological characteristics of spermatozoa were measured on d 0, 28, and 60. In year 1, blood and semen samples were collected on d 0, 28, and 60 to measure manganese superoxide dismutase activity. There was no treatment effect for blood or semen manganese superoxide dismutase concentration (P &gt; 0.255). There was a treatment effect (P &lt; 0.02) for average daily gain as bulls fed WW gained less compared to those fed WD and DD (0.96, 1.23, and 1.39 kg/d, respectively). No treatment effect was observed for scrotal circumference (P &gt; 0.50). There were no treatment × time interactions, treatment, or time main effects for percentages of normal spermatozoa, spermatozoa with coiled or folded tails, or proximal droplets (P &gt; 0.12). There was a treatment effect on the amount of swollen midpiece or abnormal head as bull in the DD treatment had a greater (P &lt; 0.02) percentage of other abnormalities compared to WW, but WD was not different (P &gt; 0.16). Inclusion of whole cottonseed may affect average daily gain, but does not affect reproductive parameters of beef bulls.