Enzyme Gene Transcription Research Articles

Tracing Zinc's Role in Preterm Infants' Health: A Narrative Review.

Zinc (Zn) is a trace element involved in numerous physiological processes, including enzyme function, gene transcription, and cell signaling. Its importance is especially pronounced in preterm infants, who are at high risk of Zn deficiency due to disrupted transplacental transfer, high nutrient demands, and medical complications. The inherent risk of Zn deficiency in this population is further increased by poor Zn dietary intake. Human milk from preterm mothers contains low concentrations of Zn, although it is highly bioavailable. Additionally, the Zn content steadily declines from colostrum (first few days postpartum) to mature milk (>10-14 d postpartum). Formula milk contains higher Zn concentrations to compensate for nutrient losses during production and storage, and lower bioavailability compared with human milk, which is further decreased in case of high phytate content, such as in soy milk-based formulas. Zn supplements may prove useful in meeting the preterm infant's needs, although caution is warranted regarding potential interactions with other nutrients within multinutrient supplements. Early detection of Zn deficiency is challenging due to the lack of reliable Zn status biomarkers, necessitating a high index of suspicion. Clinical signs of Zn deficiency can range from mild, nonspecific symptoms to severe, multisystem involvement. Chronic deficiency may lead to failure to thrive. Zn supplementation can support growth and mitigate comorbidities in preterm infants, although variability across studies complicates efforts to establish optimal dosing, and define safety and long-term effects. Although rare, Zn toxicity in preterm infants should not be overlooked, especially in infants on long-term parenteral nutrition. This narrative review aimed to consolidate existing knowledge and identify research gaps, highlighting the critical role of Zn in supporting preterm infants' health. Further research is needed to establish evidence-based practices to improve health outcomes in this vulnerable population.

Biofiltering capacity of Chambardia rubens (Bivalvia: Unionidae) may modulate expression of stress and growth genes inhibited by the neonicotinoid insecticide acetamiprid in zebrafish

Neonicotinoid insecticides specifically target insect subtypes of nicotinic acetylcholine receptors. Acetamiprid (ACE: C10H11ClN4), the neonicotinoid insecticide, is used to control crop insect pests worldwide. It is a nitrile, monochloropyridine, and carboxamidine that is highly soluble and accessible to waterways. There, it causes neurotoxic and oxidative perturbance to non-target organisms. The unionid mussel Chamabradia rubens is a common Northern River Nile suspension feeder. The current study aimed to assess ACE filtration from waters by C. rubens, and whether this biological power can reduce ACE effects on fish. Removal of ACE by C. rubens was assessed using LC-MS/MS. Zebrafish Danio rerio adults were exposed to different sublethal doses of ACE in the presence or absence of C. rubens in their aquaria. The results showed that mussels could remove significant ACE amounts from water, where it accumulated mostly in the digestive gland. The presence of C.rubens in zebrafish aquaria having ACE was accompanied by significant upregulation of antioxidant enzyme gene transcripts and total H2O2 scavenging, in contrast to mussel-free ACE-exposed groups. Meanwhile, liver triglycerides rose 5-6-fold in response to ACE in the “Fish-Only” groups, indicating an ACE-induced hepatotoxicity. Also, Insulin-like growth factor 1 (igf1) and fish body mass increased more in “Fish + Mussel” groups than in the “Fish-Only” ones. In aggregate, these findings suggest that the Nile mussel could reduce the oxidative stress and metabolic changes induced in fish by ACE. This can contribute valuable environmental and economic benefits upon the use of this mussel as a biofilter.

Lactate metabolism and acute kidney injury.

Acute kidney injury (AKI) is a common clinically critical syndrome in hospitalized patients with high morbidity and mortality. At present, the mechanism of AKI has not been fully elucidated, and no therapeutic drugs exist. As known, glycolytic product lactate is a key metabolite in physiological and pathological processes. The kidney is an important gluconeogenic organ, where lactate is the primary substrate of renal gluconeogenesis in physiological conditions. During AKI, altered glycolysis and gluconeogenesis in kidneys significantly disturb the lactate metabolic balance, which exert impacts on the severity and prognosis of AKI. Additionally, lactate-derived posttranslational modification, namely lactylation, is novel to AKI as it could regulate gene transcription of metabolic enzymes involved in glycolysis or Warburg effect. Protein lactylation widely exists in human tissues and may severely affect non-histone functions. Moreover, the strategies of intervening lactate metabolic pathways are expected to bring a new dawn for the treatment of AKI. This review focused on renal lactate metabolism, especially in proximal renal tubules after AKI, and updated recent advances of lactylation modification, which may help to explore potential therapeutic targets against AKI.

Co-exposure to deltamethrin and cyazofamid: variations in enzyme activity and gene transcription in the earthworm (Eisenia fetida).

Pesticide formulations are typically applied as mixtures, and their synergistic effects can increase toxicity to the organisms in the environment. Despite pesticide mixtures being the leading cause of pesticide exposure incidents, little attention has been given to assessing their combined toxicity and interactions. This survey purposed to reveal the cumulative toxic effects of deltamethrin (DEL) and cyazofamid (CYA) on earthworms (Eisenia fetida) by examining multiple endpoints. Our findings revealed that the LC50 values of DEL for E. fetida, following 7- and 14-day exposures, ranged from 887.7 (728-1095) to 1552 (1226-2298) mg kg-1, while those of CYA ranged from 316.8 (246.2-489.4) to 483.2 (326.1-1202) mg kg-1. The combinations of DEL and CYA induced synergistic influences on the organisms. The contents of Cu/Zn-SOD and CarE showed significant variations when exposed to DEL, CYA, and their combinations compared to the untreated group. Furthermore, the mixture administration resulted in more pronounced alterations in the expression of five genes (hsp70, tctp, gst, mt, and crt) associated with cellular stress, carcinogenesis, detoxification, and endoplasmic reticulum compared to single exposures. In conclusion, our comprehensive findings provided detailed insights into the cumulative toxic effects of chemical mixtures across miscellaneous endpoints and concentration ranges. These results underscored the importance of considering mixture administration during ecological risk evaluations of chemicals.

Perception of strigolactones and the coordinated phytohormonal regulation on rice (Oryza sativa) tillering is affected by endogenous ascorbic acid.

Phytohormones play a key role in regulating tiller number. Ascorbic acid (Asc)-phytohormone interaction plays a pivotal role in the regulation of senescence. We analysed the relationship between Asc and the enzyme concentrations and gene transcript abundances related to the signal perception of strigolactones (SLs), the contents of four phytohormones (abscisic acid, ABA; jasmonic acid, JA; indole acetic acid, IAA; cytokinin, CTK), the enzyme concentrations and gene transcript abundances related to the synthesis or transportation of these four phytohormones. Our results showed that Asc deficiency leads to the upregulation of enzyme concentrations, gene transcript abundances related to the SL signal perception, ABA synthesis and IAA transport. The altered level of Asc also leads to a change in the contents of ABA, JA, IAA and CTK. These findings support the conclusion that Asc or Asc/DHA play an important role in the signal perception and transduction of SLs, and Asc may affect the coordinated regulation of SL, IAA and CTK on rice (Oryza sativa ) tillering.

Anthocyanins as an element of nutritional support for athletes: effects and molecular mechanisms of action

Antioxidants are among the common components of sports nutrition designed to counteract oxidative stress that develops during intense physical activity. One of the promising antioxidants are anthocyanins which belong to polyphenolic compounds of plant origin (class of flavonoids). The purpose of the research was to analyze the results of prospective controlled studies on the effect of anthocyanins on physical performance, and to consider the possible molecular mechanisms of their action. Material and methods. Sources were searched in PubMed, Google Scholar, and CyberLeninka databases of peer-reviewed scientific literature without restrictions on the year of publication using the following keywords: anthocyanins, physical performance, recovery, sport and exercise nutrition, oxidative stress, inflammation. Results. The main data set on the effects of anthocyanins in athletes was obtained using extracts of blackcurrant and Montmorency tart cherry. Volunteers received anthocyanins at a dose of 86-547 mg per day for 1 to 10 days with subsequent evaluation of their performance in cycling, running and fitness activities. The possibility of favorable effect of anthocyanins on physical performance and acceleration of its recovery after exertion has been shown. The source, dose and duration of intake did not significantly influence the established effects of anthocyanins. Acting as exogenous regulators of metabolism, anthocyanins can activate several mechanisms of performance enhancement, including influence on antioxidant and immune status and apoptosis intensity. Anthocyanins prevent the formation of reactive oxygen species, neutralize electrophilic compounds by direct interaction or through activation of Nrf2 factor, which regulates the transcription of antioxidant enzyme genes. The basis of the anti-inflammatory action of anthocyanins is their ability to inhibit MARK and NF-κB mediated signal transduction. Inclusion of bilberry and blackcurrant extract in the diet prevented the intensification of myocyte apoptosis and suppression of cellular immunity induced by exhausting exercise. An additional mechanism of anthocyanin action on physical performance may be an increase in blood supply of organs and tissues due to vascular dilation caused by activation of endothelial nitric oxide synthase. Conclusion. The intake of plant extracts with a high anthocyanin content can increase physical performance and improve recovery after physical exertion, which may be due to the antioxidant and anti-inflammatory effects of anthocyanins, their ability to regulate apoptosis processes and improve blood supply to organs and tissues.

The Snf5-Hsf1 transcription module synergistically regulates stress responses and pathogenicity by maintaining ROS homeostasis in Sclerotinia sclerotiorum.

The SWI/SNF complex is guided to the promoters of designated genes by its co-operator to activate transcription in a timely and appropriate manner to govern development, pathogenesis, and stress responses in fungi. Nevertheless, knowledge of the complexes and their co-operator in phytopathogenic fungi is still fragmented. We demonstrate that the heat shock transcription factor SsHsf1 guides the SWI/SNF complex to promoters of heat shock protein (hsp) genes and antioxidant enzyme genes using biochemistry and pharmacology. This is accomplished through direct interaction with the complex subunit SsSnf5 under heat shock and oxidative stress. This results in the activation of their transcription and mediates histone displacement to maintain reactive oxygen species (ROS) homeostasis. Genetic results demonstrate that the transcription module formed by SsSnf5 and SsHsf1 is responsible for regulating morphogenesis, stress tolerance, and pathogenicity in Sclerotinia sclerotiorum, especially by directly activating the transcription of hsp genes and antioxidant enzyme genes counteracting plant-derived ROS. Furthermore, we show that stress-induced phosphorylation of SsSnf5 is necessary for the formation of the transcription module. This study establishes that the SWI/SNF complex and its co-operator cooperatively regulate the transcription of hsp genes and antioxidant enzyme genes to respond to host and environmental stress in the devastating phytopathogenic fungi.

Climbazole causes cell apoptosis and lipidosis in the liver of grass carp

Climbazole, an azole, is widely used in personal care products, pharmaceuticals, and pesticides and is frequently detected in surface water. Climbazole has showed endocrine-disrupting effects. However, the effects of climbazole in fish are still largely unclear. In this study, grass carp (Ctenopharyngodon idella) and liver cell lines (L8824 cells) were treated with climbazole at concentrations ranging from 0.2 to 20 μg/L for 42 days in vivo and 24 h in vitro to evaluate the effects on the liver, respectively. Pathological, biochemical, and gene transcription and expression analyses were conducted to examine the hepatotoxicity. Our results showed that climbazole significantly decreased the hepatosomatic index, caused cell apoptosis in vivo and in vitro, and finally accumulated lipids in the liver. Beside, climbazole increased ROS levels, reduced Nrf2 and Keap1 mRNA and protein levels, and further decreased transcription of Nrf2-dependent downstream antioxidant enzyme genes, causing oxidative stress. Moreover, climbazole increased transcription and protein levels of apoptosis-related genes. Finally, climbazole damaged mitochondrial function and structure, disrupted liver lipid metabolism. Overall, climbazole caused hepatotoxicity, leading to a high ecological risk for aquatic organisms.

WSSV exploits AMPK to activate mTORC2 signaling for proliferation by enhancing aerobic glycolysis

AMPK plays significant roles in the modulation of metabolic reprogramming and viral infection. However, the detailed mechanism by which AMPK affects viral infection is unclear. The present study aims to determine how AMPK influences white spot syndrome virus (WSSV) infection in shrimp (Marsupenaeus japonicus). Here, we find that AMPK expression and phosphorylation are significantly upregulated in WSSV-infected shrimp. WSSV replication decreases remarkably after knockdown of Ampkα and the shrimp survival rate of AMPK-inhibitor injection shrimp increases significantly, suggesting that AMPK is beneficial for WSSV proliferation. Mechanistically, WSSV infection increases intracellular Ca2+ level, and activates CaMKK, which result in AMPK phosphorylation and partial nuclear translocation. AMPK directly activates mTORC2-AKT signaling pathway to phosphorylate key enzymes of glycolysis in the cytosol and promotes expression of Hif1α to mediate transcription of key glycolytic enzyme genes, both of which lead to increased glycolysis to provide energy for WSSV proliferation. Our findings reveal a novel mechanism by which WSSV exploits the host CaMKK-AMPK-mTORC2 pathway for its proliferation, and suggest that AMPK might be a target for WSSV control in shrimp aquaculture.

Meloxicam inhibited oxidative stress and inflammatory response of LPS-stimulated bovine endometrial epithelial cells through Nrf2 and NF-κB pathways

Meloxicam is a selective cyclooxygenase-2 inhibitor and has been widely used in combination with antibiotics to alleviate uterine inflammation and provide analgesia in postpartum cows. Studies have shown that meloxicam has antioxidant and anti-inflammatory effects. However, the link between meloxicam and uterine inflammation and oxidative stress in dairy cows has not been studied. The purpose of this study was to research the effects of meloxicam (0.5 or 5 μM) on oxidative stress and inflammatory response of primary bovine endometrial epithelial cells (BEEC) stimulated by Escherichia coli lipopolysaccharide (1 μg/mL LPS). As a result, LPS stimulated the production of oxidative stress markers and the expression of inflammatory factors, accompanied by a decrease in the activity and the gene transcription of antioxidant enzymes. Co-treatment of meloxicam and LPS reduced the content of oxidative stress markers and the mRNA levels of the pro-inflammatory genes, and improved antioxidant enzyme activities and the corresponding gene expression as compared with the cells treated with LPS alone. Meloxicam attenuated the inhibitory effect of the Nrf2 pathway and the phosphorylation levels of p65 and IκBα caused by LPS. In conclusion, meloxicam alone had no effect on BEEC, but prevented oxidative stress and inflammatory response in LPS-stimulated BEEC.

The Mechanism of Bimodal Effect of DL-Butyonine Sulfoximine on Constitutive Androstane and Pregnane X Receptors In Vitro

The constitutive androstane receptor (CAR) and the pregnane X receptor (PXR) are nuclear receptors that are involved in the regulation of gene transcription of enzymes that are responsible for biotransformation and excretion of endo- and xenobiotics. The goal of the work was to study the effect of DL-butyonine sulfoximine (BSO, gamma-glutamylcysteine synthetase inhibitor) on the relative amounts of CAR and PXR in Caco-2 cells and to clarify its mechanisms. BSO was used at concentrations of 1-500 μM for 24 and 72 h. The generation of reactive oxygen species (ROS) has been evaluated using the MitoTracker Red CM-H2 XRos fluorescent probes. Cytotoxicity was analyzed by the MTT test. The relative amount of CAR and PXR was assessed by the Western blot method. It has been shown that BSO caused an increase in ROS formation at concentrations of 10, 50, and 100 μM for 24 h and at concentrations of 50 and 100 μM for 72 h. However, 500 μM BSO reduced the viability of cells during all periods of exposure. The relative amount of CAR increased in 24 h at the BSO concentrations of 50 and 100 μM and in 72 h at its concentrations of 10 and 50 μM. The amount of PXR increased in 72 h during incubation with BSO at the concentration of 50 μM and in 24 and 72 h at its concentrations of 100 and 500 μM. The combined use of BSO (50 μM, 24 h; 10 and 50 μM, 72 h) and glutathione inhibited CAR induction, whereas 50 and 100 μM BSO inhibited PXR formation for 72 h. The addition of 1 mM glutathione to the nutrient medium with BSO (100 and 500 μM, 24 h; 500 μM, 72 h) did not affect the relative amount of PXR. No effect on CAR was observed when 1 mM glutathione was used together with BSO (100 μM, 24 h; 50 and 100 μM, 72 h). Thus, BSO can induce CAR and PXR formation by both increasing the production of free radicals, thus developing oxidative stress, and by acting independently as a xenobiotic.

ToxR represses the synthesis of c-di-GMP in Vibrio parahaemolyticus

Vibrio parahaemolyticus, the main pathogen causing seafood related food poisoning worldwide, has strong biofilm formation ability. ToxR is a membrane binding regulatory protein, which has regulatory effect on biofilm formation of V. parahaemolyticus, but the specific mechanism has not been reported. c-di-GMP is an important second messenger in bacteria and is involved in regulating a variety of bacterial behaviors including biofilm formation. In this study, we investigated the regulation of ToxR on c-di-GMP metabolism in V. parahaemolyticus. Intracellular c-di-GMP in the wild type (WT) and toxR mutant (ΔtoxR) strains were extracted by ultrasonication, and the concentrations of c-di-GMP were then determined by enzyme linked immunosorbent assay (ELISA). Three c-di-GMP metabolism-related genes scrA, scrG and vpa0198 were selected as the target genes. Quantitative real-time PCR (q-PCR) was employed to calculate the transcriptional variation of each target gene between WT and ΔtoxR strains. The regulatory DNA region of each target gene was cloned into the pHR309 plasmid harboring a promoterless lacZ gene. The recombinant plasmid was subsequently transferred into WT and ΔtoxR strains to detect the β-galactosidase activity in the cellular extracts. The recombinant lacZ plasmid containing each of the target gene was also transferred into E. coli 100λpir strain harboring the pBAD33 plasmid or the recombinant pBAD33-toxR to test whether ToxR could regulate the expression of the target gene in a heterologous host. The regulatory DNA region of each target gene was amplified by PCR, and the over-expressed His-ToxR was purified. The electrophoretic mobility shift assay (EMSA) was applied to verify whether His-ToxR directly bound to the target promoter region. ELISA results showed that the intracellular c-di-GMP level significantly enhanced in ΔtoxR strain relative to that in WT strain, suggesting that ToxR inhibited the production of c-di-GMP in V. parahaemolyticus. qPCR results showed that the mRNA levels of scrA, scrG and vpa0198 significantly increased in ΔtoxR strain relative to those in WT strain, suggesting that ToxR repressed the transcription of scrA, scrG and vpa0198. lacZ fusion assay showed that ToxR was able to repress the promoter activities of scrA, scrG and vpa0198 in both V. parahaemolyticus and E. coli 100λpir. EMSA results showed that His-ToxR was able to bind to the regulatory DNA regions of scrA and scrG, but not to the regulatory DNA region of vpa0198. In conclusion, ToxR inhibited the production of c-di-GMP in V. parahaemolyticus via directly regulating the transcription of enzyme genes associated with c-di-GMP metabolism, which would be beneficial for V. parahaemolyticus to precisely control bacterial behaviors including biofilm formation.

Stress Responses Elicited by Glucose Withdrawal in Aspergillus fumigatus.

Glucose is a widely used carbon source in laboratory practice to culture Aspergillus fumigatus, however, glucose availability is often low in its “natural habitats”, including the human body. We used a physiological−transcriptomical approach to reveal differences between A. fumigatus Af293 cultures incubated on glucose, glucose and peptone, peptone (carbon limitation), or without any carbon source (carbon starvation). Autolytic cell wall degradation was upregulated by both carbon starvation and limitation. The importance of autolytic cell wall degradation in the adaptation to carbon stress was also highlighted by approximately 12.4% of the A. fumigatus genomes harboring duplication of genes involved in N-acetyl glucosamine utilization. Glucose withdrawal increased redox imbalance, altered both the transcription of antioxidative enzyme genes and oxidative stress tolerance, and downregulated iron acquisition, but upregulated heme protein genes. Transcriptional activity of the Gliotoxin cluster was low in all experiments, while the Fumagillin cluster showed substantial activity both on glucose and under carbon starvation, and the Hexadehydro-astechrome cluster only on glucose. We concluded that glucose withdrawal substantially modified the physiology of A. fumigatus, including processes that contribute to virulence. This may explain the challenge of predicting the in vivo behavior of A. fumigatus based on data from glucose rich cultures.

Expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) in mouse uterus during the peri-implantation period

ABSTRACT Nuclear factor-erythroid 2-related factor- 2 (Nrf2) is a nuclear transcription factor that facilitates transcription of genes for detoxification enzymes and antioxidant proteins. We investigated the distribution and expression of Nrf2 during the peri-implantation period. We detected Nrf2 in uteri of mice during estrus (control) and on days 1, 4, 5, 6 and 8 of pregnancy using immunohistochemistry, quantitative real-time polymerase chain reaction and western blotting. Nrf2 immunostaining was significantly greater on days 1, 5 and 6 of pregnancy compared to controls, and on days 4 and 8 of pregnancy; western blotting results were consistent with immunohistochemical observations. Nrf2 mRNA levels on days 5 and 8 were significantly higher than for control uteri. Increased expression of Nrf2 on days 1, 5 and 6 of pregnancy may be important for uterine receptivity, implantation and decidualization by protecting the developing embryo and uterus from the adverse effects of oxidative stress.

Bacillus amyloliquefaciens Lysate Ameliorates Photoaging of Human Skin Fibroblasts through NRF2/KEAP1 and TGF-β/SMAD Signaling Pathways

More and more research in dermatology and cosmetic science is devoted to the development and application of postbiotic raw materials. In order to explore the anti-photoaging efficacy and application prospect of Bacillus amyloliquefaciens lysate (BAL1) on the skin, we used 16 J/cm2 UVA stimulation of human embryonic fibroblasts (CCC-ESF-1) to establish a UVA photodamage model to investigate the anti-photoaging efficacy of BAL1 and its mechanism of action. In this study, we found that BAL1 activated the transcription of downstream antioxidant enzyme genes mainly by promoting the nuclear displacement of NF-E2-related factor 2 (Nrf2) within CCC-ESF-1, thus increasing the antioxidant capacity of antioxidant enzymes to scavenge excessive reactive oxygen species in cells. Meanwhile, BAL1 promoted intracellular TGF-β/Smad signaling pathway and reduced matrix metalloproteinase expression to alleviate the degradation of extracellular matrix. In conclusion, the results of this study demonstrate the potential benefit of BAL1 in protecting the skin against UVA-induced photoaging and highlight the potential of BAL1 in skin photoprotection.

POU-M2 promotes juvenile hormone biosynthesis by directly activating the transcription of juvenile hormone synthetic enzyme genes in Bombyx mori.

Juvenile hormone (JH) plays a key role in preventing larval precocious metamorphosis, maintaining larval state, controlling adult sexual development and promoting insect egg maturation. Genetic studies have shown that POU factor ventral veins lacking regulates JH synthesis to control the timing of insect metamorphosis. However, how POU factor regulates JH synthesis is largely unknown. Here, we found POU-M2 was highly expressed in corpora allata (CA) and specifically localized in the nucleus of CA. The overexpression of POU-M2 promoted the expression of JH synthase genes and kr-h1 and enhanced the activity of JH synthase genes promoter. Further, POU-M2 promoted the transcription of JH acid O-methyltransferase (JHAMT) by directly binding to the key cis-regulatory elements -207, -249 and -453 within the proximal regions of JHAMT promoter. Both the POU domain and homeodomain were vital for the activation of POU-M2 on JHAMT transcription. Our study reveals the mechanism by which POU-M2 regulates JHAMT transcription.

Polymorphisms of the AS3MT gene are associated with arsenic methylation capacity and damage to the P21 gene in arsenic trioxide plant workers.

Epidemiological evidence suggests that the metabolic profiles of each individual exposed to arsenic (As) are related to the risk of cancer, coronary heart disease, and diabetes. The arsenite methyltransferase (AS3MT) gene plays a key role in As metabolism. Several single nucleotide polymorphisms in the AS3MT gene may affect both enzyme activity and gene transcription. AS3MT polymorphisms are associated with the proportions of monomethylarsenic acid (MMA) and dimethylarsenic acid (DMA) in urine as well as the incidence of cancer. P21 protein is a cyclin-dependent kinase inhibitor. Mutations of the P21 gene have been found in cancer patients. In our study, we investigate whether polymorphisms of the AS3MT gene alter As methylation capacity and adversely affect the P21 gene in arsenic trioxide plant workers. The DNA damage was examined by the quantitative polymerase chain reaction. Restriction fragment length polymorphism was used to analyze the genotype of the AS3MT gene. The results showed that DNA damage in P21 gene fragments was greater in those individuals exposed to high levels of As. There was a strong positive correlation between the DNA damage to P21 gene fragments and the percentage of MMA in urine. However, DNA damage in P21 gene fragments was negatively associated with the percentage of DMA in urine (%uDMA), primary methylation index (PMI), and secondary methylation index. We found that subjects with the rs7085104 GG or GA allele were associated with higher %uDMA and PMI and less DNA damage. The subjects with the rs11191454 GG+GA or GA allele were also associated with higher %uDMA and PMI and less DNA damage. Our results suggest that rs1191454 and rs7085104 in the AS3MT gene affect the As-induced DNA damage by altering individual metabolic efficiency.

Characterization and functional study of nuclear factor erythroid 2-related factor 2 (Nrf2) in black tiger shrimp (Penaeus monodon)

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a member of the Cap'n′collar basic region leucine zipper (CNC-bZIP) transcription factor family, and is activated by diverse oxidants, pro-oxidants, antioxidants and chemopreventive agents. The full-length cDNA of Nrf2 from Penaeus monodon (PmNrf2; 2024 bp long with 729 bp coding region, GenBank accession no. MW390830) was cloned. The 242-amino-acid polypeptide encoded by this gene had a predicted molecular mass of 27.80 kDa. Sequence homology and phylogenetic analysis showed that PmNrf2 was similar to the insect Cap'n′Collar (CNC) transcription factor and mammalian Nrf2. Tissue expression profile analyzed by quantitative real-time RT-PCR (qRT-PCR) demonstrated that PmNrf2 was constitutively expressed in all examined tissues, with the highest expression observed in the intestines and the weakest expression observed in the hemocyte. PmNrf2 expression profiles were detected in the hepatopancreas of shrimp after bacterial challenge. The results suggested that PmNrf2 was involved in the responses to bacterial challenge, but the temporal expression pattern trend of PmNrf2 differed between the gram-negative and gram-positive bacterial challenges in the shrimp hepatopancreas. The recombinant PmNrf2 protein was expressed and purified through affinity chromatography. Furthermore, an anti-PmNrf2 polyclonal antibody was obtained, which was able to clearly detect PmNrf2 protein expression in the hepatopancreas of shrimp. Knockdown of PmNrf2 by RNA interference (RNAi) resulted in a reduction in the expression of PmGPx gene. Taken together, the results of our study indicated that PmNrf2 played a role in regulation the transcription of PmGPx antioxidant enzyme genes.

Exogenous silicon enhances the systemic defense of cucumber leaves and roots against CA-induced autotoxicity stress by regulating the ascorbate-glutathione cycle and photosystem II

Cinnamic acid (CA), one of the main autotoxins secreted by cucumber roots during continuous cropping, inhibits plant growth and reduces yield. Silicon (Si) is an environmentally friendly element that alleviates abiotic stresses in plants, but the mechanism underlying its resistance to autotoxicity remain unclear. Here, we used 0.8 mmol L−1 CA to study the effects of Si application on the growth, chlorophyll fluorescence, and ascorbate-glutathione (AsA-GSH) cycle of cucumber seedlings under CA inducing conditions. Our results indicated that CA significantly induced photoinhibition and overaccumulation of reactive oxygen species (ROS), thereby inhibiting cucumber growth. Treatment with 1.0 mmol L−1 Si improved plant height, stem diameter and biomass accumulation, and protected the photosynthetic electron transport function of photosystem II in the presence of CA. Similarly, Si application maintained the ROS status by increasing ascorbate (AsA) and glutathione (GSH) production, as well as the ratios of AsA/DHA and GSH/GSSG in both leaves and roots during CA stress. In addition, Si application in CA-treated seedlings enhanced the activity of key enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST), and the transcription of several enzyme genes (CsAPX, CsMDHAR and CsGR） from the AsA-GSH cycle. These results suggest that exogenous Si enhances CA tolerance in cucumber seedlings by protecting photosystem II activity, upregulating AsA-GSH pathway, and reducing ROS levels.

Effects of microwave irradiation on the expression of key flavonoid biosynthetic enzyme genes and the accumulation of flavonoid products in Fagopyrum tataricum sprouts

Tartary buckwheat (Fagopyrum tataricum) sprouts are an excellent source of dietary flavonoids. Here, we examined the effects of exposing F. tataricum ‘Chuanqiao No.1’ sprouts to various time/power settings during microwave irradiation, by determining their impact on the expression of key flavonoid biosynthetic enzyme genes and the accumulation of flavonoid products within these plants. Microwave irradiation (300 W/25–75 s) significantly upregulated the transcription of various flavonoid biosynthetic enzyme genes, including FtPAL, FtCHI, and FtFLS2, in Tartary buckwheat sprouts during incubation. Maximum rutin content (25064.19 mg/kg dry weight (DW)) was observed in 5-day-old sprouts after they were treated with microwave irradiation at 300 W/75 s, while maximum chlorogenic acid (497.95 mg/kg DW) and vitexin (345.75 mg/kg DW) content were observed after irradiation at 300 W/50 s. Additionally, maximum quercetin content (342.98 mg/kg DW) was reached in 3-day-old sprouts after irradiation at 300 W/50 s. Significant increases in myricetin and dihydromyricetin content were also observed with extended exposure time (300 W/25–125 s); however, this was countermanded by increasing the power value from 300 W to 500 W. These results suggest that among other treatment conditions, microwaving Tartary buckwheat sprouts at 300 W/50–75 s displays the best results in increasing the flavonoid content in these samples.