Effect of biopolymer chitosan on manganese immobilization improvement by microbial­induced carbonate precipitation.

Microbially induced carbonate precipitation (MICP), as an eco-friendly and promising technology that can transform free metal ions into stable precipitation, has been extensively used in remediation of heavy metal contamination. However, its depressed efficiency of heavy metal elimination remains in question due to the inhibition effect of heavy metal toxicity on bacterial activity. In this work, an efficient, low-cost manganese (Mn) elimination strategy by coupling MICP with chitosan biopolymer as an additive with reduced treatment time was suggested, optimized, and implemented. The influences of chitosan at different concentrations (0.01, 0.05, 0.10, 0.15 and 0.30 %, w/v) on bacterial growth, enzyme activity, Mn removal efficiency and microstructure properties of the resulting precipitation were investigated. Results showed that Mn content was reduced by 94.5 % within 12 h with 0.15 % chitosan addition through adsorption and biomineralization as MnCO3 (at an initial Mn concentration of 3 mM), demonstrating a two-thirds decrease in remediation time compared to the chitosan-absent system, whereas maximum urease activity increased by ∼50 %. Microstructure analyses indicated that the mineralized precipitates were spherical-shaped MnCO3, and a smaller size and more uniform distribution of MnCO3 is obtained by the regulation of abundant amino and hydroxyl groups in chitosan. These results demonstrate that chitosan accelerates nucleation and tunes the growth of MnCO3 by providing nucleation sites for mineral formation and alleviating the toxicity of metal ions, which has the potential to upgrade MICP process in a sustainable and effective manner. This work provides a reference for further understanding of the biomineralization regulation mechanism, and gives a new perspective into the application of biopolymer-intensified strategies of MICP technology in heavy metal contamination.

Role of Plant-Growth-Promoting Rhizobacteria in Plant Machinery for Soil Heavy Metal Detoxification.

Heavy metals migrate easily and are difficult to degrade in the soil environment, which causes serious harm to the ecological environment and human health. Thus, soil heavy metal pollution has become one of the main environmental issues of global concern. Plant-growth-promoting rhizobacteria (PGPR) is a kind of microorganism that grows around the rhizosphere and can promote plant growth and increase crop yield. PGPR can change the bioavailability of heavy metals in the rhizosphere microenvironment, increase heavy metal uptake by phytoremediation plants, and enhance the phytoremediation efficiency of heavy-metal-contaminated soils. In recent years, the number of studies on the phytoremediation efficiency of heavy-metal-contaminated soil enhanced by PGPR has increased rapidly. This paper systematically reviews the mechanisms of PGPR that promote plant growth (including nitrogen fixation, phosphorus solubilization, potassium solubilization, iron solubilization, and plant hormone secretion) and the mechanisms of PGPR that enhance plant-heavy metal interactions (including chelation, the induction of systemic resistance, and the improvement of bioavailability). Future research on PGPR should address the challenges in heavy metal removal by PGPR-assisted phytoremediation.

Environmental concentrations of microplastic-induced gut microbiota and metabolite disruption in silkworm, Bombyx mori.

Microplastics (MPs) existing extensively in various ecosystems can be ingested by marine organisms and enter the food chain, resulting the health risks from the presence of MPs in aquatic and terrestrial ecosystems. In the present study, an ideal model for Lepidoptera, the silkworm, Bombyx mori, was exposed to environmental concentrations (0.125 µg, 0.25 µg or 0.5 µg/diet) of MPs for 5 days, and the global changes in gut microbes and metabolites were subsequently examined via 16S rDNA sequencing and GC‒MS-based metabolomics. The results showed that MPs exposure did not seriously threaten survival but may regulate signaling pathways involved in development and cocoon production. MPs exposure induced gut microbiota perturbation according to the indices of α-diversity and ß-diversity, and the functional prediction of the altered microbiome and associated metabolites demonstrated the potential roles of the altered microbiome following MPs exposure in the metabolic and physiological states of silkworm. The metabolites markedly altered following MPs exposure may play vital biological roles in energy metabolism, lipid metabolism, xenobiotic detoxification and the immune system by directly or indirectly affecting the physiological state of silkworms. These findings contribute to assessing the health risks of MPs exposure in model insects and provide novel insight into the toxicity mechanism of MPs.

The effects of short-term dietary exposure to SiO2 nanoparticle on the domesticated lepidopteran insect model silkworm (Bombyx mori): Evidence from the perspective of multi-omics.

Silicon dioxide nanoparticles (nSiO2) are one of the widely utilized nanoparticle (NPSs) materials, and exposure to nSiO2 is ubiquitous. With the increasing commercialization of nSiO2, the potential risk of nSiO2 release to the health and the ecological environment have been attracted more attention. In this study, the domesticated lepidopteran insect model silkworm (Bombyx mori) was utilized to evaluate the biological effects of dietary exposure to nSiO2. Histological investigations showed that nSiO2 exposure resulted in midgut tissue injury in a dose-dependent manner. Larval body mass and cocoon production were reduced by nSiO2 exposure. ROS burst was not triggered, and the activities of antioxidant enzymes were induced in the midgut of silkworm exposure to nSiO2. RNA-sequencing revealed that the differentially expressed genes induced by nSiO2 exposure were predominantly enriched into xenobiotics biodegradation and metabolism, lipid, and amino acid metabolism pathways. 16 S rDNA sequencing revealed that nSiO2 exposure altered the microbial diversity in the gut of the silkworm. Metabolomics analysis showed that the combined uni- and multivariate analysis identified 28 significant differential metabolites from the OPLS-DA model. These significant differential metabolites were predominantly enriched into the metabolic pathways, including purine metabolism and tyrosine metabolism and so. Spearman correlation analysis and the Sankey diagram established the relationship between microbe and metabolites, and some genera may play crucial and pleiotropic functions in the interaction between microbiome and host. These findings indicated that nSiO2 exposure could impact the dysregulation of genes related to xenobiotics metabolism, gut dysbiosis, and metabolic pathways and provided a valuable reference for assessing nSiO2 toxicity from a multi-dimensional perspective.

Theaflavin-3,3'-digallate ameliorates learning and memory impairments in mice with premature brain aging induced by D-galactose.

Age-related neurodegenerative diseases accompanied by learning and memory deficits are growing in prevalence due to population aging. Cellular oxidative stress is a common pathomechanism in multiple age-related disorders, and various antioxidants have demonstrated therapeutic efficacy in patients or animal models. Many plants and plant extracts possess potent antioxidant activity, but the compounds responsible are frequently unknown. Identification and evaluation of these phytochemicals is necessary for optimal targeted therapy. A recent study identified theaflavin-3,3'-digallate (TFDG) as the most potent among a large series of phytochemical antioxidants. Here we examined if TFDG can mitigate learning and memory impairments in the D-galactose model of age-related neurodegeneration. Experimental mice were injected subcutaneously with D-galactose (120 mg/kg) for 56 days. In treatment groups, different doses of TFDG were administered daily by gavage starting on day 29 of D-galactose injection. Model mice exhibited poor learning and memory in the novel object recognition and Y-maze tests, reduced brain/body mass ratio, increased brain glutamate concentration and acetylcholinesterase activity, decreased brain acetylcholine concentration, and lower choline acetyltransferase, glutaminase, and glutamine synthetase activities. Activities of antioxidant enzymes glutathione peroxidase and superoxide dismutase were also reduced, while the concentration of malondialdehyde, a lipid peroxidation product, was elevated. Further, antioxidant genes Nrf2, Prx2, Gsh-px1, and Sod1 were downregulated in brain. Each one of these changes was dose-dependently reversed by TFDG. TFDG is an effective antioxidant response inducer and neuroprotectant that can restore normal neurotransmitter metabolism and ameliorate learning and memory dysfunction in the D-galactose model of age-related cognitive decline.

Circadian effects of ionizing radiation on reproductive function and clock genes expression in male mouse.

BACKGROUND: Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far. METHODS: Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-ß, or Ror-γ. RESULTS: Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-ß, or Ror-γ) in testis, with alteration in the rhythm parameters. CONCLUSION: These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.

Microarray profiling of LncRNA expression in the testis of pubertal mice following morning and evening exposure to 1800 MHz radiofrequency fields.

In this paper, the chronotoxicity of radiofrequency fields (RF) in the pubertal testis development and the involved molecular pathways were investigated by exposing four-week-old mice to RF (1800 MHz, SAR, 0.50 W/kg) in the morning and evening of each day for three weeks. Then, pathological changes and functional indices within the testis were determined. We also used a long non-coding RNA (lncRNA) microarray and GO/KEGG pathway analyses to determine lncRNA expression profiles and predict their potential functions. The cis and trans regulation of lncRNAs were investigated, and an interaction network was constructed using Cytoscape software. RF exposure led to a range of pathological changes in the testes of adolescent mice, as testicular weights and daily sperm productions decreased, and the testosterone secretion reduced. Furthermore, RF induced dysregulation in the expression of testicular lncRNAs. We identified 615 and 183 differentially expressed lncRNAs that were associated with morning and evening exposure to RF, respectively. From 15 differential expression lncRNAs both in morning RF group and evening RF group, we selected 6 lncRNAs to be validated by quantitative reverse transcription PCR (qRT-PCR). The differentially expressed lncRNAs induced by morning RF exposure were highly correlated with many different pathways, including Fanconi syndrome, metabolic processes, cell cycle, DNA damage, and DNA replication. Trans-regulation analyses further showed that differentially expressed lncRNAs were involved in multiple transcription factor-regulated pathways, such as TCFAP4, NFkB, HINFP, TFDP2, FoxN1, and PAX5. These transcription factors have all been shown to be involved in the modulation of testis development, cell cycle progression, and spermatogenesis. These findings suggest that the extent to which 1800 MHz RF induced toxicity in the testes and changed the expression of lncRNAs showed differences between morning exposure and evening exposure. These data indicate that differentially expressed lncRNAs play crucial roles in the RF exposure damage to the developing pubertal testis. Collectively, our findings provide a better understanding of the mechanisms underlying the toxic effects of RF exposure on testicular development.

[Joint effects of nano-selenium and nano-cerium on the male reproductive function of mice exposed to microwave radiation].

OBJECTIVE: To study effect of nano-selenium and nano-cerium(nano cerium oxide) on the spermatogenic ability of mice irradiated by 1800 MHz microwave radiation(MR). METHODS: Forty-two ICR mice were randomly divided into groups: blank control group, solvent control group, microwave radiation model group, low, medium and high dose groups of nano-selenium+nano-cerium. In joint effects groups of nano-selenium and nano-cerium, the nano-selenium solution(60, 120 and 240 µg/kg) and the nano-cerium oxide solution(15, 30, 60 µg/kg) were administered to the stomach at 7:30 in the morning and 18:30 in the evening, respectively. The blank control group was orally administered with an equal volume of distilled water, and the solvent control group and the MR group were orally administered with an equal volume of carboxymethylcellulose sodium solution. During the second week of gastric administration, the mice were exposed to microwave radiation(1800 MHz) for 2 h every day(specific absorption ratio: 0. 2986 W/kg). After MR treatment, the daily sperm production of testis, sperm motility and sperm deformity rate in epididymis were measured, and the testicular marker enzymes [G6 PDH(6-phosphatedehydrogenase), ACP(acid phosphatase), LDH(lactate dehydrogenase)], antioxidant indexes [CAT(catalase), MDA(malondialdehyde) and T-AOC(total antioxidant capacity)] in testicular tissue were analyzed. RESULTS: Compared with the solvent control group, MR led to the decrease of sperm motility and the increase of sperm deformity rate, decreased the enzymes activities of G6 PDH, ACP and CAT, increased LDH activity and MDA content, and decreased the T-AOC level in testicular tissue, and the differences were statistically significant(P<0. 05). Compared with the MR group, the joint action of nano-selenium and nano-cerium with medium dose increased the daily sperm production of testis((18. 98±1. 27) ×10~6/g) vs. (15. 53±1. 24) ×10~6/g), decreased the sperm deformity rate(11. 74%±0. 91% vs. 16. 84%±2. 05%), and the joint action of nano-selenium and nano-cerium with medium and high dose increased the sperm motility in epididymis(61. 98%±6. 33%, 54. 17±4. 38 vs. 45. 16%±5. 01%), and the differences were statistically significant(P<0. 05). Compared with the MR group, the joint action of nano-selenium and nano-cerium with low and medium dose increased the activity of ACP(11. 07±0. 98, 14. 85±1. 39 vs. 8. 72±0. 91 nmol/(min·mg prot), P<0. 05). The joint action of nano-selenium and nano-cerium with medium and high dose increased the activity of G6 PDH(24. 12±2. 06, 21. 36±3. 65 vs. 15. 11±1. 73 nmol/(min·mg prot), P<0. 05) and decreased the activity of LDH(15. 52±1. 17, 13. 51±1. 68 vs. 22. 46±2. 01 nmol/(min·mg prot), P<0. 05). The joint action of nano-selenium and nano-cerium with medium dose increased the activity of CAT(17. 92±2. 03 vs. 11. 69±0. 87 nmol/(min·mg prot), P<0. 05) and decreased the content of MDA(5. 17 ±0. 62 vs. 9. 03 ±0. 63 nmol/mg prot, P<0. 05). The joint action of nano-selenium and nano-cerium with low, medium and high dose increased the level of T-AOC(22. 06±1. 54, 29. 36±2. 39, 21. 01±2. 47 vs. 12. 88±1. 82 U/mg prot, P<0. 05). CONCLUSION: The joint addition of nano-selenium and nano-cerium can improve the reproductive function of male mice exposed to MR, and can effectively alleviate the changes of mouse testicular marker enzyme activity and the decline of antioxidant capacity caused by MR.

The antitumor effect of hinesol, extract from Atractylodes lancea (Thunb.) DC. by proliferation, inhibition, and apoptosis induction via MEK/ERK and NF-κB pathway in non-small cell lung cancer cell lines A549 and NCI-H1299.

Lung cancer (especially, non-small cell lung cancer [NSCLC]) is one of the most malignant cancers in the world. Hinesol is the major component of the essential oil of Atractylodes lancea (Thunb.) DC and possesses the most promising anticancer function. However, the effects and molecular mechanism of hinesol on antiproliferation in NSCLC cells has not been well understood. In this study, we found that hinesol effectively inhibited the A549 and NCI-H1299 cells in a dose- and time-dependent manner by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay. In addition, hinesol induced cell cycle arrest at G0/G1 phase and apoptosis assessed by flow cytometry in A549 cells. Furthermore, Western blot analysis showed that hinesol decreased phosphorylation of mitogen-activated protein kinase, extracellular signal-regulated kinase, IκBα, and p65 inhibited the expressions of Bcl-2, cyclin D1 and upregulated the expression of Bax. Based on these results, hinesol might be a potential drug candidate of anti-NSCLC for therapy.

CeO2NPs relieve radiofrequency radiation, improve testosterone synthesis, and clock gene expression in Leydig cells by enhancing antioxidation.

Introduction: The ratio of Ce3+/Ce4+ in their structure confers unique functions on cerium oxide nanoparticles (CeO2NPs) containing rare earth elements in scavenging free radicals and protecting against oxidative damage. The potential of CeO2NPs to protect testosterone synthesis in primary mouse Leydig cells during exposure to 1,800 MHz radiofrequency (RF) radiation was examined in vitro. Methods: Leydig cells were treated with different concentrations of CeO2NPs to identify the optimum concentration for cell proliferation. The cells were pretreated with the optimum dose of CeO2NPs for 24 hrs and then exposed to 1,800 MHz RF at a power density of 200.27 µW/cm2 (specific absorption rate (SAR), 0.116 W/kg) for 1 hr, 2 hrs, or 4 hrs. The medium was used to measure the testosterone concentration. The cells were collected to determine the antioxidant indices (catalase [CAT], malondialdehyde [MDA], and total antioxidant capacity [T-AOC]), and the mRNA expression of the testosterone synthase genes (Star, Cyp11a1, and Hsd-3ß) and clock genes (Clock, Bmal1, and Rorα). Results: Our preliminary result showed that 128 µg/mL CeO2NPs was the optimum dose for cell proliferation. Cells exposed to RF alone showed reduced levels of testosterone, T-AOC, and CAT activities, increased MDA content, and the downregulated genes expression of Star, Cyp11a1, Hsd-3ß, Clock, Bmal1, and Rorα. Pretreatment of the cells with 128 µg/mL CeO2NPs for 24 hrs followed by RF exposure significantly increased testosterone synthesis, upregulated the expression of the testosterone synthase and clock genes, and increased the resistance to oxidative damage in Leydig cells compared with those in cells exposed to RF alone. Conclusion: Exposure to 1,800 MHz RF had adverse effects on testosterone synthesis, antioxidant levels, and clock gene expression in primary Leydig cells. Pretreatment with CeO2NPs prevented the adverse effects on testosterone synthesis induced by RF exposure by regulating their antioxidant capacity and clock gene expression in vitro. Further studies of the mechanism underlying the protective function of CeO2NPs against RF in the male reproductive system are required.

Dietary nano cerium oxide promotes growth, relieves ammonia nitrogen stress, and improves immunity in crab (Eriocheir sinensis).

Oxidative stress plays a crucial role in ammonia nitrogen toxicity. In this study, the beneficial effects of dietary nano cerium oxide (nano CeO2) as a potent antioxidant were examined in the Chinese mitten crab (Eriocheir sinensis). Crabs were fed a diet supplemented with 0, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, or 12.8 mg/kg nano CeO2 for 60 d. The optimum supplementation level of nano CeO2 that significantly increased weight gain rate and decreased feed coefficient was 0.8 mg/kg. This level also offered immune protection when crabs were kept under ammonia nitrogen stress and/or exposed to pathogen infection (Aeromonas hydrophila). Supplementation with 0.8 mg/kg of CeO2 (i) relieved pathological damage to the hepatopancreas; (ii) increased hemocyte counts, including total number of hemocytes, granulocytes, and hyalinocytes; (iii) decreased malondialdehyde content and increased antioxidant enzyme activities of superoxide dismutase and catalase in the hemolymph; (iv) increased the activities of lysozyme, acid phosphatase, and alkaline phosphatase in the hemolymph; and (v) increased gene and protein expression of cathepsin L in the hepatopancreas. Mortality increased when crabs were injected with bacteria under ammonia nitrogen stress, but dietary supplementation with 0.8 mg/kg nano CeO2 decreased the mortality rate. Thus, the results of this study suggested that dietary supplementation with nano CeO2 in crabs promoted growth and up-regulated immunity to bacterial infection under ammonia nitrogen stress.

[Chronotoxicity of 1.8 GHz radio-frequency radiation on plasma stress hormones and immune factors in mice].

OBJECTIVE: To study the chronotoxicity of radio-frequency radiation(RF) on the plasma stress hormones and immune factors in mice. METHODS: A total of 72 healthy C57 BL mice with circadian rhythm were divided into twelve groups: 6 Sham group and 6 RF groups. RF groups were exposed to 1.8 GHz RF at 226 µW/cm~2 for 60 days with 2 h/day respectively at corresponding zeitgeber time(ZT 0:00, ZT 4:00, ZT 8:00, ZT 12:00, ZT 16:00, ZT 20:00). The Sham group mice were exposed to the same condition without electromagnetic signal. At the end of last RF exposure, blood samples were collected from each animal. The concentrations of plasma stress hormones(ACTH, CORT) and immune factors(GM-CSF, TNF-α) were determined by enzyme linked immunosorbent assay(ELISA) method. RESULTS: The daily average levels of ACTH, CORT, GM-CSF and TNF-α were 84.12, 60.14, 1112.02 and 594.49 ng/L, which were decreased to 62.07, 41.21, 84.18 and 305.08 ng/L after 60 days of RF exposure. Compared to sham-exposed animals, the daily average levels of ACTH, CORT, GM-CSF and TNF-α were all significantly decreased(P<0.05). Circadian rhythms in the secreting of CORT, GM-CSF, TNF-α were disappeared(P>0.05), circadian rhythms of ACTH was shifted in RF-exposed mice, with the amplitude reduced from 12.45 to 4.88 and peak time postponed from 1:39 to 5:29. CONCLUSION: 1.8 GHz RF may weaken the function of stress and immune, and disturb their circadian rhythmicities.

SF-1 mediates reproductive toxicity induced by Cerium oxide nanoparticles in male mice.

BACKGROUND: Cerium oxide nanoparticles (CeO2 NPs) have potential application for use in biomedical and in various consumer products. However, it is largely unclear whether CeO2 NPs have effects on male reproductive function. METHODS: In this study, male mice were examined for toxicity, if any, following chronic oral administration of CeO2 NPs for 32 days. In each animal, epididymides were examined for sperm motility and DNA integrity. Bloods were tested for testosterone levels. Testicular tissues were collected to determine the element Ce content, the daily sperm production (DSP), marker enzymes such as ACP, G6PD, γ-GT and SDH, mRNA expression levels of steroidogenesis genes Star, P450scc, P450c17, 3ß-Hsd, and 17ß-Hsd, as well as steroidogenic factor-1 (SF-1) gene/protein levels. RESULTS: The results showed that CeO2 NPs (20 mg/kg and 40 mg/kg) increased the element Ce content in testis, the testis histopathological patterns and sperm DNA damage whereas decreased the testis weight, DSP and sperm motility. There were also remarkable reduction in testosterone levels and marker enzymes activities, down-regulated mRNA expression levels of several steroidogenesis genes such as Star, P450scc, P450c17, 3ß-Hsd, and 17ß-Hsd, as well as altered gene and protein expressions of SF-1. CONCLUSION: These results reveal the male reproductive toxicity of chronic exposure of CeO2 NPs in mice, hinting that the utilization of CeO2 NPs need to be carefully evaluated about their potential reproductive toxicity on the human health.

1800 MHz radiofrequency fields inhibits testosterone production via CaMKI /RORα pathway.

Exposure to radiofrequency fields (RF) has been reported to induce adverse effects on testosterone production and its daily rhythm. However, the mechanisms underneath this effect remain unknown. In this study, male mice were exposed to 1800 MHz radiofrequency fields (RF, 40 µW/cm2 power intensity and 0.0553 W/Kg SAR) 2 h per day for 32 days. The data suggested that RF exposure: (i) significantly reduced testosterone levels, (ii) altered the expression of genes involved in its synthesis (Star, P450scc, P450c17 and 3ß-Hsd) in testicular tissue, (iii) significantly reduced regulatory protein CaMKI/RORα. Similar observations were also made in cultured primary Leydig cells exposed in vitro to RF. However, all of these observations were blocked by CaMK inhibitor, KN-93, and ionomycin reversed the down-regulation effects on intracellular [Ca2+]i and CaMKI/RORα expression induced by RF exposure. Thus, the data provided the evidence that RF-induced inhibition of testosterone synthesis might be mediated through CaMKI/RORα signaling pathway. Capsule: CaMKI/RORα signaling pathway was involved in the inhibition of testosterone synthesis induced by RF exposure.

[Effects of cerium oxide nanoparticles on cognitive function in 48 h sleep deprived male mice].

OBJECTIVE: To study the effects of cerium oxide nanoparticles( CeO_2 NPs)on cognitive function in 48 hours of sleep deprived male mice and explore its mechanism. METHODS: Thirty-six healthy clean ICR male mice( four weeks old) were randomly divided into 6 groups: blank control group, solvent control group, sleep deprivation control group, low, medium and high dose groups of CeO_2 NPs. 1 m L of distilled water were given to mice of blank group, 1 m L of solvent were given to mice of solvent control and sleep deprivation control group, 1 mL of CeO_2 NPs solvent( 4, 8, 16 mg/kg) were administered to mice of low, medium and high dose groups of CeO_2 NPs. Each group of mice received intragastric administration for 30 days. On the 31 st day, a single platform water environment method was used for 48 hours of sleep deprivation on mice. Then, the cognitive ability of the mice was tested by Y-maze. Further, the antioxidant( CAT, MDA, T-AOC) and neurotransmitters( NO, Glu) in mice brain tissue were measured also. RESULTS: Compare with the solvent control group, 48 hours of sleep deprivation reduced the cognitive ability of mice [( 36 ± 2) times vs. ( 20 ± 2) times, P = 0. 0006; 10. 753%± 0. 031% vs. 24. 927% ± 0. 972%, P = 0. 00000045 ], CAT activity [( 78. 151 ±17. 683) nmol/mg prot vs. ( 198. 155 ± 14. 437) nmol/mg prot, P = 0. 0008]and the level of T-AOC [( 103. 630 ± 24. 209) U/mg prot vs. ( 264. 599 ± 50. 223) U/mg prot, P =0. 007], but improved the content of MDA [( 9. 499 ± 1. 249) nmol/mg prot vs. ( 6. 157± 0. 373) nmol/mg prot, P = 0. 0113 ], NO [( 11. 608 ± 1. 281) µmol/mg prot vs. ( 3. 628 ± 1. 064) µmol/mg prot, P = 0. 001]and Glu[( 4. 731 ± 0. 131) µg/mg prot vs. ( 4. 476 ± 0. 126) µg/mg prot, P = 0. 03] in the brain. Low, medium and high dose Ce O2 NPs enhanced cognitive performance of the sleep deprived mice. Among three dose groups, the medium dose groups most significantly improved the cognitive ability of mice[( 27 ± 2) times vs. ( 36 ± 2) times, P = 0. 005; 18. 743% ± 0. 245% vs. 10. 753% ±0. 031%, P = 0. 0000006 ], increased CAT activities [( 238. 065 ± 19. 393) nmol/mg prot vs. ( 78. 151 ± 17. 683) nmol/mg prot, P = 0. 00045] and T-AOC levels [( 210. 516± 11. 339) U/mg prot vs. ( 103. 630 ± 24. 209) U/mg prot, P = 0. 002], decreased MDA[( 6. 528 ± 1. 162) nmol/mg prot vs. ( 9. 499 ± 1. 249) nmol/mg prot, P = 0. 039], NO[( 5. 651 ± 0. 239) µmol/mg prot vs. ( 11. 608 ± 1. 281) µmol/mg prot, P = 0. 001]and Glu levels [( 4. 358 ± 0. 016) µg/mg prot vs. ( 4. 731 ± 0. 131) µg/mg prot, P = 0. 008]. CONCLUSION: Ce O2 NPs can improve the cognitive ability of sleep deprived male mice, improve the antioxidant capacity of brain, reduce free radical damage to the nerves of brain, and regulate the neurotransmitters of brain.

Mechanisms underlying melatonin-mediated prevention of fenvalerate-induced behavioral and oxidative toxicity in zebrafish.

The neurotoxic effects attributed to the pesticide fenvalerate (FEN) are well-established. The aim of this study was to determine whether melatonin (MLT) was able to protect against FEN-induced behavior, oxidative stress, apoptosis, and neurogenesis using zebrafish (Danio rerio) model. Zebrafish exposed to 100 µg/L FEN for 120 h exhibited decreased swimming activity accompanied by downregulated expression of neurogenesis-related genes (Dlx2, Shha, Ngn1, Elavl3, and Gfap), suggesting that neurogenesis were impaired. In addition, FEN exposure significantly elevated oxidative stress as evidenced by increased malondialdehyde levels, as well as activities of Cu/Zn superoxide dismutase (Cu/Zn SOD), catalase, and glutathione peroxidase. Acridine orange staining demonstrated that embryos treated with FEN for 120 h significantly enhanced apoptosis mainly in the brain. FEN also produced upregulation of the expression of the pro-apoptotic genes (Bax, Fas, caspase 8, caspase 9, and caspase 3) and decreased expression of the anti-apoptotic gene Bcl-2. MLT significantly attenuated the FEN-mediated oxidative stress, modulated apoptotic-regulating genes, and diminished apoptotic responses. Further, MLT blocked the FEN-induced effects on swimming behavior as well as on neurogenesis-related genes. In conclusion, MLT protected against FEN-induced developmental neurotoxicity and apoptosis by inhibiting pesticide-mediated oxidative stress in zebrafish.

Dietary nano-selenium relieves hypoxia stress and, improves immunity and disease resistance in the Chinese mitten crab (Eriocheir sinensis).

Hypoxia is a relevant physiological challenge for crab culture, and the hemolymph plays a crucial role in response to the hypoxia. In a 60 d feeding trial, Chinese mitten crabs (Eriocheir sinensis) fed a diet containing 0.2 mg/kg nano-selenium (nanoSe) showed a significantly increased weight gain rate (WGR) and a reduced feed coefficient (FC) compared to those fed diets with 0, 0.1, 0.4, 0.8, and 1.6 mg/kg nanoSe. Another 90 d feeding trial was conducted to determine the influence of dietary nanoSe on the immune response in juvenile Chinese mitten crabs kept under the condition of hypoxia. The results showed that hypoxia stress resulted in significantly increased hemocyte counts (THC, LGC, SGC, and HC), expression levels of the hemocyanin gene and protein, lactic acid level, and antioxidant capacity (T-AOC activities, SOD activities, GSH-Px and GSH content) in hemolymph supernatant. When these crabs were infected with Aeromonas hydrophila bacteria, hypoxia exposure increased mortality, but it was alleviated by a diet supplemented with 0.2 mg/kg nanoSe. The up-regulative effects of nanoSe (0.2 mg/kg) on antioxidant capacity, hemocyte counts, and hemocyanin expression under hypoxia exposure were further strengthened throughout, whereas lactic acid levels induced by hypoxia stress were restored. Thus, the observations in this study indicate that the level of dietary nanoSe is important in regulating immunity and disease resistance in crabs kept under hypoxia stress.

Inhibitory effect of melatonin on testosterone synthesis is mediated via GATA-4/SF-1 transcription factors.

The aim of the present study was to elucidate whether the GATA-4/SF-1 signalling pathway is involved in the inhibitory effects of melatonin on testosterone production in both the TM3 Leydig cell line and in C57BL/6J mice. In-vitro experiments demonstrated that melatonin treatment significantly reduced testosterone levels in cell culture medium (P < 0.05 or P < 0.01); and decreased intracellular cyclic adenosine monophospha accumulation (P < 0.05 or P < 0.01) and mRNA/protein expression of GATA-4, SF-1 (NR5A1), StAR, P450SCC (CYP11A1) and 3ß-HSD (P < 0.05 or P < 0.01). These effects were blocked by N-acetyl-2-benzyltryptamin, a melatonin receptor antagonist. Similar effects of melatonin on testosterone production (P < 0.05 or P < 0.01) and down-regulation of transcription factors GATA-4 and SF-1 (P < 0.01) were also observed in mice treated with intratesticular injections of melatonin. Overall, the data suggest that the inhibitory effects of melatonin on testosterone production are mediated via down-regulation of GATA-4 and SF-1 expression.

Circadian rhythmicity of antioxidant markers in rats exposed to 1.8 GHz radiofrequency fields.

BACKGROUND: The potential health risks of exposure to Radiofrequency Fields (RF) emitted by mobile phones are currently of considerable public interest, such as the adverse effects on the circadian rhythmicities of biological systems. To determine whether circadian rhythms of the plasma antioxidants (Mel, GSH-Px and SOD) are affected by RF, we performed a study on male Sprague Dawley rats exposed to the 1.8 GHz RF. METHODS: All animals were divided into seven groups. The animals in six groups were exposed to 1.8 GHz RF (201.7 µW/cm² power density, 0.05653 W/kg specific absorption rate) at a specific period of the day (3, 7, 11, 15, 19 and 23 h GMT, respectively), for 2 h/day for 32 consecutive days. The rats in the seventh group were used as sham-exposed controls. At the end of last RF exposure, blood samples were collected from each rat every 4 h (total period of 24 h) and also at similar times from sham-exposed animals. The concentrations of three antioxidants (Mel, GSH-Px and SOD) were determined. The data in RF-exposed rats were compared with those in sham-exposed animals. RESULTS: circadian rhythms in the synthesis of Mel and antioxidant enzymes, GSH-Px and SOD, were shifted in RF-exposed rats compared to sham-exposed animals: the Mel, GSH-Px and SOD levels were significantly decreased when RF exposure was given at 23 and 3 h GMT. CONCLUSION: The overall results indicate that there may be adverse effects of RF exposure on antioxidant function, in terms of both the daily antioxidative levels, as well as the circadian rhythmicity.

Adaptive response in mice exposed to 900 MHZ radiofrequency fields: bleomycin-induced DNA and oxidative damage/repair.

PURPOSE: To determine whether mice exposed to radiofrequency fields (RF) and then injected with a radiomimetic drug, bleomycin (BLM), exhibit adaptive response and provide some mechanistic evidence for such response. MATERIALS AND METHODS: Adult mice were exposed to 900 MHz RF at 120 µW/cm(2) power density for 4 hours/day for 7 days. Immediately after the last exposure, some mice were sacrificed while the others were injected with BLM 4 h later. In each animal: (i) The primary DNA damage and BLM-induced damage as well as its repair kinetics were determined in blood leukocytes; and (ii) the oxidative damage was determined from malondialdehyde (MDA) levels and the antioxidant status was assessed from superoxide dismutase (SOD) levels in plasma, liver and lung tissues. RESULTS: There were no indications for increased DNA and oxidative damages in mice exposed to RF alone in contrast to those treated with BLM alone. Mice exposed to RF+ BLM showed significantly: (a) reduced BLM-induced DNA damage and that remained after each 30, 60, 90, 120 and 150 min repair time, and (b) decreased levels of MDA in plasma and liver, and increased SOD level in the lung. CONCLUSIONS: The overall data suggested that RF exposure was capable of inducing adaptive response and mitigated BLM- induced DNA and oxidative damages by activating certain cellular processes.