Selenoprotein K knockdown induces apoptosis in skeletal muscle satellite cells via calcium dyshomeostasis-mediated endoplasmic reticulum stress.

Skeletal muscle satellite cells (SMSCs), known as muscle stem cells, play an important role in muscle embryonic development, post-birth growth, and regeneration after injury. Selenoprotein K (SELENOK), an endoplasmic reticulum (ER) resident selenoprotein, is known to regulate calcium ion (Ca2+) flux and ER stress (ERS). SELENOK deficiency is involved in dietary selenium deficiency-induced muscle injury, but the regulatory mechanisms of SELENOK in SMSCs development remain poorly explored in chicken. Here, we established a SELENOK deficient model to explore the role of SELENOK in SMSCs. SELENOK knockdown inhibited SMSCs proliferation and differentiation by regulating the protein levels of paired box 7 (Pax7), myogenic factor 5 (Myf5), CyclinD1, myogenic differentiation (MyoD), and Myf6. Further analysis exhibited that SELENOK knockdown markedly activated the ERS signaling pathways, which ultimately induced apoptosis in SMSCs. SELENOK knockdown-induced ERS is related with ER Ca2+ ([Ca2+]ER) overload via decreasing the protein levels of STIM2, Orai1, palmitoylation of inositol 1,4,5-trisphosphate receptor 1 (IP3R1), phospholamban (PLN), and plasma membrane Ca2+-ATPase (PMCA) while increasing the protein levels of sarco/endoplasmic Ca2+-ATPase 1 (SERCA1) and Na+/Ca2+ exchanger 1 (NCX1). Moreover, thimerosal, an activator of IP3R1, reversed the overload of [Ca2+]ER, ERS, and subsequent apoptosis caused by SELENOK knockdown. These findings indicated that SELENOK knockdown triggered ERS driven by intracellular Ca2+ dyshomeostasis and further induced apoptosis, which ultimately inhibited SMSCs proliferation and differentiation.

Selenium alleviates endoplasmic reticulum calcium depletion-induced endoplasmic reticulum stress and apoptosis in chicken myocardium after mercuric chloride exposure.

Mercury is a highly toxic heavy metal with definite cardiotoxic properties and can affect the health of humans and animals through diet. Selenium (Se) is a heart-healthy trace element and dietary Se has the potential to attenuate heavy metal-induced myocardial damage in humans and animals. This study was designed to explore antagonistic effect of Se on the cardiotoxicity of mercuric chloride (HgCl2) in chickens. Hyline brown hens received a normal diet, a diet containing 250 mg/L HgCl2, or a diet containing 250 mg/L HgCl2 and 10 mg/kg Na2SeO3 for 7 weeks, respectively. Histopathological observations demonstrated that Se attenuated HgCl2-induced myocardial injury, which was further confirmed by the results of serum creatine kinase and lactate dehydrogenase levels assay and myocardial tissues oxidative stress indexes assessment. The results showed that Se prevented HgCl2-induced cytoplasmic calcium ion (Ca2+) overload and endoplasmic reticulum (ER) Ca2+ depletion mediated by Ca2+-regulatory dysfunction of ER. Importantly, ER Ca2+ depletion led to unfolded protein response and endoplasmic reticulum stress (ERS), resulting in apoptosis of cardiomyocytes via PERK/ATF4/CHOP pathway. In addition, heat shock protein expression was activated by HgCl2 through these stress responses, which was reversed by Se. Moreover, Se supplementation partially eliminated the effects of HgCl2 on the expression of several ER-settled selenoproteins, including selenoprotein K (SELENOK), SELENOM, SELENON, and SELENOS. In conclusion, these results suggested that Se alleviated ER Ca2+ depletion and oxidative stress-induced ERS-dependent apoptosis in chicken myocardium after HgCl2 exposure.

ART1 and putrescine contribute to rice aluminum resistance via OsMYB30 in cell wall modification.

Cell wall is the first physical barrier to aluminum (Al) toxicity. Modification of cell wall properties to change its binding capacity to Al is one of the major strategies for plant Al resistance; nevertheless, how it is regulated in rice remains largely unknown. In this study, we show that exogenous application of putrescines (Put) could significantly restore the Al resistance of art1, a rice mutant lacking the central regulator Al RESISTANCE TRANSCRIPTION FACTOR 1 (ART1), and reduce its Al accumulation particularly in the cell wall of root tips. Based on RNA-sequencing, yeast-one-hybrid and electrophoresis mobility shift assays, we identified an R2R3 MYB transcription factor OsMYB30 as the novel target in both ART1-dependent and Put-promoted Al resistance. Furthermore, transient dual-luciferase assay showed that ART1 directly inhibited the expression of OsMYB30, and in turn repressed Os4CL5-dependent 4-coumaric acid accumulation, hence reducing the Al-binding capacity of cell wall and enhancing Al resistance. Additionally, Put repressed OsMYB30 expression by eliminating Al-induced H2 O2 accumulation, while exogenous H2 O2 promoted OsMYB30 expression. We concluded that ART1 confers Put-promoted Al resistance via repression of OsMYB30-regulated modification of cell wall properties in rice.

Mercuric chloride induces sequential activation of ferroptosis and necroptosis in chicken embryo kidney cells by triggering ferritinophagy.

Mercuric chloride (HgCl2) is an environmental pollutant with serious nephrotoxic effects, but the underlying mechanism of HgCl2 nephrotoxicity is not well understood. Ferroptosis and necroptosis are two programmed cell death (PCD) modalities that have been reported singly in heavy metal-induced kidney injury. However, the interaction between ferroptosis and necroptosis in HgCl2-induced kidney injury is unclear. Here, we established a model of HgCl2-exposed chicken embryo kidney (CEK) cells to dissect the progresses and mechanisms of these two PCDs. We found that ferroptosis was initially activated in CEK cells after HgCl2 exposure for 12 h, and necroptosis was activated subsequently at 24 h. Importantly, further study indicated that the shift from ferroptosis to necroptosis was driven by ROS, which was produced by iron-dependent Fenton reaction, and the iron chelation by DFO prevented the sequential activation of both ferroptosis and necroptosis. To investigate the source of intracellular iron, the regulation of iron homeostasis was first explored and demonstrated a tendency for intracellular iron overload in CEK cells. Interestingly, the cellular ferritin, a free iron depository, decreased in a time-dependent manner. Further studies revealed that the degradation of ferritin was attributed to the activation of selective cargo receptor nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy, and the inhibition of ferritinophagy by CQ prevented the HgCl2-induced cell death. In conclusion, our study demonstrated that HgCl2 released excess free iron via ferritinophagy, led to a sustained accumulation of ROS and ultimately activated ferroptosis and necroptosis sequentially. These findings provide a new understanding for the nephrotoxic mechanism of HgCl2.

Protective mechanism of selenium on mercuric chloride-induced testis injury in chicken via p38 MAPK/ATF2/iNOS signaling pathway.

Mercuric chloride (HgCl2) is a well-known toxic heavy metal contaminant, which causes male reproductive function defects. Selenium (Se) has been recognized as an effective antioxidant against heavy metals-induced male reproductive toxicity. The aim of present study was to explore the potentially protective mechanism of Se on HgCl2-induced testis injury in chicken. Firstly, the results showed that Se mitigated HgCl2-induced testicular injury through increasing the blood-testis barrier (BTB) cell-junction proteins expression of occludin, zonula occludens-1 (ZO-1), connexin 43 (Cx43), and N-cadherin. Secondly, Se alleviated HgCl2-induced oxidative stress through decreasing the malondialdehyde (MDA) content and increasing the superoxidase dismutase (SOD), glutathione peroxidase (GSH-Px) activities as well as the total antioxidant capacity (T-AOC) level. Thirdly, Se inhibited the activation of p38 MAPK signaling through decreasing the proteins expression of phosphorylated-p38 (p-p38) and phosphorylated-ATF2 (p-ATF2), and alleviated inflammation response through decreasing the proteins expression of inducible nitric oxide synthase (iNOS), nuclear factor kappa B (NF-κB), tissue necrosis factor-alpha (TNF-α), and cyclooxygenase 2 (COX2). Collectively, these results demonstrated that Se effectively alleviated HgCl2-induced testes injury via improving antioxidant capacity to reduce inflammation mediated by p38 MAPK/ATF2/iNOS signaling pathway in chicken. Our data shed a new light on potential mechanisms of Se antagonized HgCl2-induced male reproductive toxicity.

Selenium ameliorates mercuric chloride-induced brain damage through activating BDNF/TrKB/PI3K/AKT and inhibiting NF-κB signaling pathways.

Mercuric chloride (HgCl2), a heavy metal compound, causes neurotoxicity of animals and humans. Selenium (Se) antagonizes heavy metal-induced organ damage with the properties of anti-oxidation and anti-inflammation. Nevertheless, the molecular mechanism underlying the protective effects of sodium selenite (Na2SeO3) against HgCl2-induced neurotoxicity remains obscure. Therefore, the present study aimed to explore the protective mechanism of Na2SeO3 on HgCl2-induced brain damage in chickens. Morphological observations showed that Na2SeO3 alleviated HgCl2-induced brain tissues damage. The results also showed that Na2SeO3 decreased the protein expression of S100 calcium binding protein B (S100B), and increased the levels of nerve growth factors (NGF), doublecortin domain containing 2 (DCDC2), as well as neurotransmitter to reverse HgCl2-induced brain dysfunction. Further, Na2SeO3 attenuated HgCl2-induced oxidative stress by decreasing the level of malondialdehyde (MDA) and increasing the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC). Mechanistically, Na2SeO3 activated the brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase receptor type B (TrKB)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway and suppressed the nuclear factor kappa B (NF-κB) signaling pathway to inhibit apoptosis and inflammation caused by HgCl2 exposure. In summary, Na2SeO3 ameliorated HgCl2-induced brain injury via inhibiting apoptosis and inflammation through activating BDNF/TrKB/PI3K/AKT and suppressing NF-κB pathways.

Antagonistic effect of selenium on mercuric chloride in the central immune organs of chickens: The role of microRNA-183/135b-FOXO1/TXNIP/NLRP3 inflammasome axis.

Mercury (Hg) is a persistent environmental and industrial pollutant that accumulated in the body and induces oxidative stress and inflammation damage. Selenium (Se) has been reported to antagonize immune organs damage caused by heavy metals. Here, we aimed to investigate the prevent effect of Se on mercuric chloride (HgCl2 )-induced thymus and bursa of Fabricius (BF) damage in chickens. The results showed that HgCl2 caused immunosuppression by reducing the relative weight, cortical area of the thymus and BF, and the number of peripheral blood lymphocytes. Meanwhile, HgCl2 induced oxidative stress and imbalance in cytokines expression in the thymus and BF. Further, we found that thioredoxin-interacting protein (TXNIP) and the NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome mediated HgCl2 -induced oxidative stress and inflammation. Mechanically, the targeting and inhibitory effect of microRNA (miR)-135b/183 on forkhead box O1 (FOXO1) were an upstream event for HgCl2 -activated TXNIP/NLRP3 inflammasome pathway. Most importantly, Se effectively attenuated the aforementioned damage in the thymus and BF caused by HgCl2 and inhibited the TXNIP/NLRP3 inflammasome pathway by reversing the expression of FOXO1 through inhibiting miR-135b/183. In conclusion, the miR-135b/183-FOXO1/TXNIP/NLRP3 inflammasome axis might be a novel mechanism for Se to antagonize HgCl2 -induced oxidative stress and inflammation in the central immune organs of chickens.

[Alleviating effects of hydrogen on hyperhomocysteinemia and fatty liver induced by high-methionine diet].

Objective: To investigate the alleviating effect of hydrogen (H2) on homocysteine (Hcy) levels and non alcoholic fatty liver in rats with hyperhomocysteinemia (HHcy). Methods: After one week of adaptive feeding, Wistar rats were randomly divided into three groups: the general diet group (CHOW), the high methionine group (HMD), and the high methionine plus hydrogen rich water group (HMD+HRW), with 8 rats in each group. The CHOW group was fed with AIN-93G feed, while the HMD and HMD+HRW groups were fed with AIN-93G+2% methionine feed to construct an HHcy model. The HMD+HRW group was also gavaged with hydrogen rich water (3 ml/animal, twice a day, with a hydrogen concentration of 0.8 mmol/L), and body weight data were recorded. After 6 weeks of feeding, the plasma and liver samples were processed and collected. The plasma homocysteine (Hcy) and lipid contents of each group were measured, and the histological morphology of the liver was observed. The activities of key enzymes in the Hcy metabolism pathway and mRNA expression were detected in the liver. Results: Compared with the CHOW group rats, the Hcy level in the blood of HMD rats was significantly increased significantly (P＜0.05). Pathological tissue sections showed liver enlargement, injury, and fatty liver in the rats; Compared with the HMD group rats, the HMD+HRW group rats showed a significant decrease in Hcy in the blood, reduced liver damage, and increased Hcy metabolism key enzyme activity and mRNA expression in the liver, with statistical differences (P＜0.05). Conclusion: Hydrogen has a significant improvement effect on liver injury induced by HMD diet in HHcy rats, possibly by enhancing the three metabolic pathways of Hcy to reduce excessive Hcy in the body, thereby improving liver metabolic function and symptoms of non-alcoholic fatty liver disease.

Aberrant Gene Expression of Selenoproteins in Chicken Spleen Lymphocytes Induced by Mercuric Chloride.

Mercury (Hg) is a heavy metal widely distributed in ecological environment, poisoning the immune system of humans and animals. Selenium (Se) is an essential microelement and selenoproteins involved in the procedure of Se antagonizing organ toxicity induced by heavy metals. The aim of this research was to investigate the changes of gene expression profile of selenoproteins induced by mercuric chloride (HgCl2) in chicken spleen lymphocytes. We established cytotoxicity model of chicken spleen lymphocytes by HgCl2 exposure, the messenger RNA (mRNA) expression levels of 25 selenoproteins in spleen lymphocytes were analyzed by real-time quantitative PCR (qPCR), and the gene expression pattern of selenoproteins was revealed by principal component analysis (PCA). The results showed that the mRNA expression levels of 13 selenoproteins (GPX3, GPX4, TXNRD2, TXNRD3, DIO2, SELENOS, SELENON, SELENOT, SELENOO, SELENOP, SELENOP2, MSRB1, and SEPHS2) were decreased in HgCl2 treatment group, and there was strong positive correlation between these selenoproteins and component 1 as well as component 2 of the PCA. At the same time, the protein expression levels of GPX4, TXNRD1, TXNRD2, SELENOM, SELENOS, and SELENON were detected by Western blotting, which were consistent with the changes of gene expression. The results showed that the expression levels of selenoproteins were aberrant in response to HgCl2 toxicity. The information presented in this study provided clues for further research on the interaction between HgCl2 and selenoproteins, and the possible mechanism of immune organ toxicity induced by HgCl2.

Selenium alleviates mercury chloride-induced liver injury by regulating mitochondrial dynamics to inhibit the crosstalk between energy metabolism disorder and NF-κB/NLRP3 inflammasome-mediated inflammation.

Mercury (Hg) is a persistent heavy metal contaminant with definite hepatotoxicity. Selenium (Se) has been shown to alleviate liver damage induced by heavy metals. Therefore, the present study aimed to explore the mechanism of the antagonistic effect of Se on mercury chloride (HgCl2)-induced hepatotoxicity in chickens. Firstly, we confirmed that Se alleviated HgCl2-induced liver injury through histopathological observation and liver function analyzation. The results also showed that Se prevented HgCl2-induced liver lipid accumulation and dyslipidemia by regulating the gene expression related to lipid as well as glucose metabolism. Moreover, Se blocked the nuclear factor kappa B (NF-κB)/NLR family pyrin domain containing 3 (NLRP3) inflammasome signaling pathway, which was the key to alleviate the inflammation caused by HgCl2. Mechanically, Se inhibited immoderate mitochondrial division, fusion, and biogenesis caused by HgCl2, and also improved mitochondrial respiration, which were essential for preventing energy metabolism disorder and inflammation. In conclusion, our results suggested that Se inhibited energy metabolism disorder and inflammation by regulating mitochondrial dynamics, thereby alleviating HgCl2-induced liver injury in chickens. These results are expected to provide potential intervention and therapeutic targets for diseases caused by inorganic mercury poisoning.

Suppression of rice miR168 improves yield, flowering time and immunity.

MicroRNA168 (miR168) is a key miRNA that targets Argonaute1 (AGO1), a major component of the RNA-induced silencing complex1,2. Previously, we reported that miR168 expression was responsive to infection by Magnaporthe oryzae, the causal agent of rice blast disease3. However, how miR168 regulates immunity to rice blast and whether it affects rice development remains unclear. Here, we report our discovery that the suppression of miR168 by a target mimic (MIM168) not only improves grain yield and shortens flowering time in rice but also enhances immunity to M. oryzae. These results were validated through repeated tests in rice fields in the absence and presence of rice blast pressure. We found that the miR168-AGO1 module regulates miR535 to improve yield by increasing panicle number, miR164 to reduce flowering time, and miR1320 and miR164 to enhance immunity. Our discovery demonstrates that changes in a single miRNA enhance the expression of multiple agronomically important traits.

Response of selenoproteins gene expression profile to mercuric chloride exposure in chicken kidney.

Kidney is a primary target organ for mercuric chloride (HgCl2) toxicity. Selenium (Se) can exert antagonistic effect on heavy metals-induced organ toxicity by regulating the expression of selenoproteins. The objective of this study was to investigate the effect of HgCl2 on the gene expression of selenoproteins in chicken kidney. Sixty male Hyline brown chickens were randomly and evenly divided into two groups. After acclimatization for one week, chickens were provided with the standard diet as well as non-treated water (CON group), and standard diet as well as HgCl2-treated water (250 ppm, HgCl2 group). After seven weeks, kidney tissues were collected to examine the mRNA expression levels of 25 selenoproteins genes and protein expression levels of 4 selenoproteins. Moreover, correlation analysis and principal component analysis (PCA) were used to analyze the expression patterns of 25 selenoproteins. The results showed that HgCl2 exposure significantly decreased the mRNA expression of Glutathione peroxidase 1 (GPX1), GPX4, Thioredoxin reductase 2 (TXNRD2), Iodothyronine deiodinase 1 (DIO1), Methionine-Rsulfoxide reductase 1 (SELR), 15-kDa selenoprotein (SEP15), selenoprotein I (SELI), SELK, SELM, SELN, SELP, SELS, SELT, SELW, and SEPHS2. Meanwhile, HgCl2 exposure significantly increased the mRNA expression of GPX3, TXNRD1, and SELU. Western blot analysis showed that the expression levels of GPX3, TXNRD1, SELK, and SELN were concordant with these mRNA expression levels. Analysis results of selenoproteins expression patterns showed that HgCl2-induced the main disorder expression of selenoproteins with antioxidant activity and endoplasmic reticulum resident selenoproteins. In conclusion, selenoproteins respond to HgCl2 exposure in a characteristic manner in chicken kidney.

[Effects of total sleep deprivation on attention network conflict and sample entropy analysis of EEG].

Objective: To explore the effects of total sleep deprivation (TSD) on brain attention network and to analyze the effects of sleep deprivation on individual selective attention network conflict effect and electroencephalograph (EEG) sample entropy. Methods: Twenty-five healthy subjects participated in the test from 9: 00am that day to 9: 00pm next day. The subjects completed the attention network task (ANT) before and after TSD, and synchronously recorded the EEG signals. Sample entropy algorithm was used to analyze the changes of EEG complexity in delta, theta, alpha, beta and gamma frequency bands before and after TSD. Results: Compared with before TSD, the reaction time of attention network conflict effect was significantly decreased after TSD (P＜0. 01), and rate was increased significantly (P＜0. 01). Sample entropy analysis of EEG showed that in beta frequency bands, the sample entropy related to attention network conflict control was increased significantly after TSD (P＜0. 01). No significant difference was found in other EEG frequency bands. Conclusion: TSD reduces the effect of brain attention network conflict, reflecting the decline of conflict control ability after 36 h TSD.

[Effect of 36h total sleep deprivation on the object working memory: an ERP study].

Objective: To investigate the effects of 36 h total sleep deprivation (TSD) on object working memory by event related potential(ERP). Methods: We used a pre-post-design, sixteen healthy college students (age range: 21-28 years, mean age: 23 years) received object working memory tasks while awake and after 36 hours of TSD and simultaneously recording electroencephalograph (EEG) data while completing 2-back object working memory tasks. ERP data were statistically analyzed using repeated measurements analysis of variance to observe the changes in the working memory-related P2, N2 and P3 components. Results: After 36 h TSD, the latency of N2 waves related to object working memory significantly was prolonged (P＜0.05), and the amplitude was decreased, but difference did not reach statistical significance (P＞0.05). The latency of P2 was significantly prolonged after TSD (P＜0.05). There was no significant difference in the change of latency and amplitude of P3 waves (P＞0.05). Conclusion: 36 h of total sleep deprivation affected working memory-related components and impaired object working memory capacity.

Osa-miR398b boosts H2 O2 production and rice blast disease-resistance via multiple superoxide dismutases.

miRNAs contribute to plant resistance against pathogens. Previously, we found that the function of miR398b in immunity in rice differs from that in Arabidopsis. However, the underlying mechanisms are unclear. In this study, we characterized the mutants of miR398b target genes and demonstrated that multiple superoxide dismutase genes contribute to miR398b-regulated rice immunity against the blast fungus Magnaporthe oryzae. Out of the four target genes of miR398b, mutations in Cu/Zn-Superoxidase Dismutase1 (CSD1), CSD2 and Os11g09780 (Superoxide DismutaseX, SODX) led to enhanced resistance to M. oryzae and increased hydrogen peroxide (H2 O2 ) accumulation. By contrast, mutations in Copper Chaperone for Superoxide Dismutase (CCSD) resulted in enhanced susceptibility. Biochemical studies revealed that csd1, csd2 and sodx displayed altered expression of CSDs and other superoxide dismutase (SOD) family members, leading to increased total SOD enzyme activity that positively contributed to higher H2 O2 production. By contrast, the ccsd mutant showed CSD protein deletion, resulting in decreased CSD and total SOD enzyme activity. Our results demonstrate the roles of different SODs in miR398b-regulated resistance to rice blast disease, and uncover an integrative regulatory network in which miR398b boosts total SOD activity to upregulate H2 O2 concentration and thereby improve disease resistance.

Toxicity and Sublethal Effects of Flupyradifurone, a Novel Butenolide Insecticide, on the Development and Fecundity of Aphis gossypii (Hemiptera: Aphididae).

The cosmopolitan pest Aphis gossypii (Glover) causes considerable economic losses on various crops by its feeding damage and transmitting diseases around the world. Flupyradifurone is a novel butenolide pesticide; its toxicity on A. gossypii parent generation (F0) was estimated following treatment with LC25 concentration for 48 h. The adult longevity and fecundity of the F0 individuals treated by flupyradifurone showed no significant decrease in comparison with the control. Life table method was used to evaluate the sublethal effects on progeny population (F1). Results showed that the development time of the fourth instar and the preadult as well as the total pre-reproductive period were significantly prolonged, while their fecundity was significantly decreased compared with the control. Additionally, the intrinsic rate of increase (r), the finite rate of increase (λ), and the net reproductive rate (R0) of F1 were all significantly lower in the group treated by LC25 than in the control group. These results reveal that the sublethal concentration of flupyradifurone could suppress the population growth of A. gossypii and indicate that this novel insecticide may be as a useful tool in pest management.

Transcriptional responses of detoxification genes to four plant allelochemicals in Aphis gossypii.

Aphis gossypii Glover (Hemiptera: Aphididae) can damage a variety of agricultural crops, so it is very important for cotton aphids to evolve adaptive mechanisms to various allelochemicals from host plants. Our results aim to provide a fundamental and rich resource for exploring aphid functional genes in A. gossypii. A transcriptome data set and five expression profile data sets of A. gossypii samples were analyzed by Illumina sequencing platform. In total, 53,763,866 reads were assembled into 1,963,516 contigs and 28,555 unigenes. Compared with the control, 619 genes were significantly up- or downregulated in the treatment group by 2-tridecanone. There were 516, 509, and 717 of differential expression genes in tannic acid, quercetin, and gossypol treatment groups, respectively. Furthermore, there were 4 of 54 putative cytochrome P450 genes and 1 of 7 putative carboxylesterases downregulated in all treatment groups by four plant allelochemicals. When aphids fed on 2-tridecanone, tannic acid, and quercetin, only one P450 gene was upregulated. These results show that plant allelochemical stress can induce differential gene expression in A. gossypii. The differential response information of gene expression based on a large-scale sequence would be useful to reveal molecular mechanisms of adaptation for A. gossypii to plant allelochemicals.

Identification of microRNAs and their response to the stress of plant allelochemicals in Aphis gossypii (Hemiptera: Aphididae).

BACKGROUND: MicroRNAs (miRNAs) are a group of short non-coding RNAs involved in the inhibition of protein translation or in mRNA degradation. Although the regulatory roles of miRNAs in various biological processes have been investigated, there is as yet an absence of studies about the regulatory roles of miRNAs involved in the metabolism of plant allelochemicals in insects. RESULTS: We constructed five small RNA libraries from apterous Aphis gossypii adults that had fed on an artificial diet containing various allelochemicals. Using Illumina sequencing, a total of 73.27 million clean reads was obtained, and 292 miRNAs were identified from A. gossypii. Comparative analysis of read counts indicated that both conserved and novel miRNAs were differently expressed among the five libraries, and the differential expression was validated via qRT-PCR. We found that the transcript levels of several miRNAs were increased or decreased in all of the allelochemical treatment libraries compared to the control. The putative target genes of the miRNAs were predicted using in silico tools, and the target genes of several miRNAs were presumed to be involved in the metabolism of xenobiotic compounds. Furthermore, the target prediction results were confirmed using dual luciferase reporter assay, and Ago-miR-656a-3p was demonstrated to regulate the expression of CYP6J1 post-transcriptionally through binding to the 3' UTR of CYP6J1. CONCLUSION: Our research results indicate that miRNAs may be involved in the metabolism of plant allelochemicals in A. gossypii, and these results also represent an important new small RNA genomics resource for further studies on this topic.

[Effect of nano-SiO2 exposure on spatial learning and memory and LTP of hippocampal dentate gyrus in rats].

OBJECTIVE: To study the effect of nano-SiO2 on spatial learning and memory. METHODS: Twenty-four male rats were randomly divided into 3 groups: control group (C group), low dose group (L group) and high dose group (H group). The rats were intragastrically administrated with nanometer particles at 25 and 100 mg/kg body weight every day for 4 weeks. After exposure, the ability of learning and memory of rats was tested by Morris water maze, and electrophysiological brain stereotactic method was used to test long-tear potentiation (LTP) in dentate gyrus (DG) of the rats. RESULTS: The increase rate of body weight in H group was reduced significantly compared with C group ( P < 0.05). In the space exploration experiment of Morris water maze test, the escape latency of H group was longer than that of C group (P < 0.05). The rats of H group spent less time in finding the target quadrant (P < 0.05) . The rate of LP induction of H group was significantly lower than that of C group (P < 0.05). After high fre quency stimulation (HFS), The changes of amplitude of population spike (PS) of L group and H group were lower than those of C group significantly (P < 0.05, P < 0.01). CONCLUSION: Nano-SiO2may result in impairment of spatial learning and memory ability by reducing the rate of LTP induction and the increase of PS in hippocampus.