Country risk and its impact on renewable energy investment in highly polluted economies.

The country's risk may significantly impact every sector of the economy, and the energy sector is no exception. However, no past study has empirically tested the relationship between country risk and renewable energy investment. Therefore, this study is an effort to investigate the relationship between country risk and renewable energy investment in highly polluted economies. We have employed different econometric techniques to analyze the relationship between renewable energy investment and country risk, including the OLS, 2SLS, GMM, and panel quantile regressions. The estimate of country risk influence renewable energy investment negatively in OLS, 2SLS, and GMM models. Similarly, the country's risk negatively impacts the renewable energy investment from the 10th to 60th quantiles in the panel quantile regression model. Moreover, the GDP, CO2 emissions, and technological development help promote renewable energy investment in OLS, 2SLS, and GMM models, while the human capital and financial development do not significantly impact the renewable energy investment. Furthermore, in the panel quantile regression model, the GDP and CO2 emission estimates are positively significant almost at all quantiles, and the estimate of technological development and human capital are positively significant at higher quantiles only. Therefore, the authorities in highly polluted economies should consider the respective countries' risk considerations while formulating rules about renewable energy.

Role of Foxo6 in insulin resistance of vascular endothelial cells induced by high glucose and high fat and its interaction with NF-κB pathway / 中国药理学通报

Aim To investigate the expression of Foxos in human umbilical vein endothelial cells(HUVECs)with insulin resistance(IR)induced by high glucose and high fat(HG/HF)stress and its significance.Methods First, the IR model of endothelial cells was established by HG /HF stress.The differential expression of Foxos gene in normal(Ctrl )group and HG /HF group was observed, and the subtypes with the most significant changes in Foxos were screened out, such as Foxo6.Next, Foxo6 was silenced to observe its role in endothelial cell with IR.Finally, whether the mechanism of Foxo6-mediated IR was related to the interaction of NF-κB signaling was investigated.Results The expression increase of Foxo6 was the most significant among Foxos under the IR condition induced by HG/HF.Using a small RNA interference and plasmid transfection technique, we found that the silence effect of the siRNA3 fragments targeting Foxo6 was the most significant among the siRNAs.Moreover, the further study showed that silencing the Foxo6 gene could significantly reverse the endothelial IR induced by HG/HF, and the mechanism of the reversal effect was related to the interaction between the Foxo6 and NF-κB signal.Conclusions Foxo6 mediates the endothelial cell IR induced by the HG /HF stress.The underlying mechanism is that Foxo6 can interact with NF-κBp65 and activate NF-κB signaling pathway.Silencing Foxo6 can improve the IR of vascular endothelial cells induced by HG /HF stress.

Effect of the Seasonal Adaptability on Carbohydrate-electrolyte Beverage Efforts on Post-exercise Rehydration in Healthy Young Men / 中国医学科学院学报

Objective To compare the effects of carbohydrate-electrolyte beverage on post-exercise rehydration of healthy young men in different seasons,and to explore the influence of seasonal adaptability on fluid and electrolyte balance.Methods Fifteen healthy men,aged(24.4±0.5)years,completed 2 trails in a random crossover design both in summer and winter.During recovery,they consumed a drink volume equivalent to 100% of their sweat loss with plain boiled water(the water group)or carbohydrate-electrolyte beverage(the beverage group).Recovery was monitored for further 180 minutes by the collection of blood and urine samples.Results The dehydration time in summer was significantly shorter by about 20 minutes than that in winter(

A novel flavivirus entry inhibitor, BP34610, discovered through high-throughput screening with dengue reporter viruses.

Dengue virus (DENV) is a global health problem that affects approximately 3.9 billion people worldwide. Since safety concerns were raised for the only licensed vaccine, Dengvaxia, and since the present treatment is only supportive care, the development of more effective therapeutic anti-DENV agents is urgently needed. In this report, we identified a potential small-molecule inhibitor, BP34610, via cell-based high-throughput screening (HTS) of 12,000 compounds using DENV-2 reporter viruses. BP34610 reduced the virus yields of type 2 DENV-infected cells with a 50% effective concentration (EC50) and selectivity index value of 0.48 ±â€¯0.06 µM and 197, respectively. Without detectable cytotoxicity, the compound inhibited not only all four serotypes of DENV but also Japanese encephalitis virus (JEV). Time-of-addition experiments suggested that BP34610 may act at an early stage of DENV virus infection. Sequencing analyses of several individual clones derived from BP34610-resistant viruses revealed a consensus amino acid substitution (S397P) in the N-terminal stem region of the E protein. Introduction of S397P into the DENV reporter viruses conferred an over 14.8-fold EC90 shift for BP34610. Importantly, the combination of BP34610 with a viral replication inhibitor, ribavirin, displayed synergistic enhancement of anti-DENV-2 activity. Our results identify an effective small-molecule inhibitor, BP34610, which likely targets the DENV E protein. BP34610 could be developed as an anti-flavivirus agent in the future.

A Dengue Virus Type 2 (DENV-2) NS4B-Interacting Host Factor, SERP1, Reduces DENV-2 Production by Suppressing Viral RNA Replication.

Host cells infected with dengue virus (DENV) often trigger endoplasmic reticulum (ER) stress, a key process that allows viral reproduction, without killing the host cells until the late stage of the virus life-cycle. However, little is known regarding which DENV viral proteins interact with the ER machinery to support viral replication. In this study, we identified and characterized a novel host factor, stress-associated ER protein 1 (SERP1), which interacts with the DENV type 2 (DENV-2) NS4B protein by several assays, for example, yeast two-hybrid, subcellular localization, NanoBiT complementation, and co-immunoprecipitation. A drastic increase (34.5-fold) in the SERP1 gene expression was observed in the DENV-2-infected or replicon-transfected Huh7.5 cells. The SERP1 overexpression inhibited viral yields (37-fold) in the DENV-2-infected Huh7.5 cells. In contrast, shRNAi-knockdown and the knockout of SERP1 increased the viral yields (3.4- and 16-fold, respectively) in DENV-2-infected HEK-293 and Huh7.5 cells, respectively. DENV-2 viral RNA replication was severely reduced in stable SERP1-expressing Huh7.5 cells transfected with DENV-2 replicon plasmids. The overexpression of DENV-2 NS4B alleviated the inhibitory effect of SERP1 on DENV-2 RNA replication. Taking these results together, we hypothesized that SERP1 may serve as an antiviral player during ER stress to restrict DENV-2 infection. Our studies revealed novel anti-DENV drug targets that may facilitate anti-DENV drug discovery.

Mutagenesis of the dengue virus NS4A protein reveals a novel cytosolic N-terminal domain responsible for virus-induced cytopathic effects and intramolecular interactions within the N-terminus of NS4A.

The NS4A protein of dengue virus (DENV) has a cytosolic N terminus and four transmembrane domains. NS4A participates in RNA replication and the host antiviral response. However, the roles of amino acid residues within the N-terminus of NS4A during the life cycle of DENV are not clear. Here we explore the function of DENV NS4A by introducing a series of alanine substitutions into the N-terminus of NS4A in the context of a DENV infectious clone or subgenomic replicon. Nine of 17 NS4A mutants displayed a lethal phenotype due to the impairment of RNA replication. M2 and M14 displayed a more than 10 000-fold reduction in viral yields and moderate defects in viral replication by a replicon assay. Sequencing analyses of pseudorevertant viruses derived from M2 and M14 viruses revealed one consensus reversion mutation, A21V, within NS4A. The A21V mutation apparently rescued viral RNA replication in the M2 and M14 mutants although not to wild-type (WT) levels but resulted in 100- and 1000-fold lower titres than that of the WT, respectively. M2 Rev1 (M2+A21V) and M14 Rev1 (M14+A21V) mutants displayed phenotypes of smaller plaque size and WT-like assembly/secretion by a transpackaging assay. A defect in the virus-induced cytopathic effect (CPE) was observed in HEK-293 cells infected with either M2 Rev1 or M14 Rev1 mutant virus by MitoCapture staining, cell proliferation and lactate dehydrogenase release assays. In conclusion, the results revealed the essential roles of the N-terminal NS4A in both RNA replication and virus-induced CPE. Intramolecular interactions in the N-terminus of NS4A were implicated.

Expression levels of serum miR-210 and miR-375 in patients with non-small cell lung cancer / 国际检验医学杂志

Objective To investigate the expression levels of serum miR-210and miR-375in patients with non-small cell lung cancer (NSCLC).Methods A total of 25NSCLC patients (NSCLC group) and 14healthy volunteers (control group) were enrolled in this study.The relative expression levels of 9miRNAs (miR-182, miR-126, miR-31, miR-21, miR-221, miR-200b, miR-183, miR-210and miR-375) in 6 NSCLC patients and 6healthy volunteers were measured by RT-qPCR.The dysregulated miRNAs will be selected as candidate miR-NAs.The diagnostic value were evaluated by ROC curve.Results Compared with control group, 2 (miR-210and miR-375) out of 9miRNAs were up-regulated in NSCLC group, and the differences were statistically significant (P＜0.05), while the other 7miRNAs were not consistent with the reported literatures.Therefore, miR-210and miR-375were selected as candidate miRNAs.We found that the relative expression level of miR-210in the lung adenocarcinoma group was significantly different from control group (P＜0.05), while there was no significant difference between the squamous cell carcinoma group and the control group (P＞0.05).There was no significantly statistical difference in the relative expression level of miR-375between lung squamous cell carcinoma group, lung adenocarcinoma group and the control group (P＞0.05).The AUC of serum miR-210of lung adenocarcinoma group was 0.737 5 (95％CI:0.498 3-0.976 7, P=0.091 4) with a medium diagnostic value.Conclusion MiR-210is highly expressed in the serum of patients with lung adenocarcinoma, suggesting that miR-210may be a novel tumor marker for the diagnosis of lung adenocarcinoma.The value of miR-375in the diagnosis of lung cancer still needs to be further explored.

Effect of Capsaicin on Proliferation and HMGB1 and IL-6 Expressions in Hepatoma SMMC-7721 Cells / 中国实验方剂学杂志

Objective: To investigate the effect of capsaicin on proliferation in human hepatoma SMMC-7721 cells and its possible molecular mechanism. Method: Capsaicin (50,100,150,200,250,300 μmol·L-1) groups and blank group were set up. The cell viability was detected by cell counting kit-8 (CCK-8) assay after SMMC-7721 cells were treated with capsaicin (50,100,150,200,250,300 μmol·L-1) for 24, 48, 72 h. The morphological changes were observed under an inverted microscope after SMMC-7721 cells were treated with capsaicin (150,200,250 μmol·L-1) for 24 h. The mRNA expression levels of high mobility group box 1 (HMGB1) and interleukin-6(IL-6) were measured by Real-time PCR after SMMC-7721 cells were treated with capsaicin (150,200,250 μmol·L-1) for 24 h. The levels of HMGB1 and IL-6 in cell culture supernatant were detected by enzyme-linked immunosorbent assay(ELISA) after SMMC-7721 cells were treated with capsaicin (150,200,250 μmol·L-1) for 24 h. Result: Compared with the blank group, there was no significant difference between 50 and 100 μmol·L-1 capsaicin groups treated for 24, 48, 72 h; after treated with the other concentrations of capsaicin (150, 200, 250, 300 μmo·L-1) at different time points, the proliferation inhibition rate was statistically significant (P-1) groups showed different degrees of morphological changes in SMMC-7721 cells, which became round and wrinkled, with a poor attachment and more exfoliation; compared with the blank group, the mRNA expressions of HMGB1 and IL-6 in SMMC-7721 cells of capsaicin (150, 200, 250 μmol·L-1) groups were significantly down-regulated (PPConclusion: Capsaicin inhibits cell proliferation of SMMC-7721 cells, and the possible mechanism may be related to the down-regulation of HMGB1 and IL-6 at the mRNA and protein levels.

Development of robust genotype 1a hepatitis C replicons harboring adaptive mutations for facilitating the antiviral drug discovery and study of virus replication.

The hepatitis C virus (HCV) subgenomic replicon is a valuable tool for studying virus replication and HCV drug development. Despite the fact that HCV genotype 1a (HCV1a) is the most prevalent genotype in the United States, few HCV1a reporter replicon constructs have been reported, and their replication capacities are not as efficient as those of HCV1b or 2a, especially in transient expression. In this study, we selected efficient HCV1a replicons and characterized the novel adaptive mutations derived from stable HCV1a (strain H77) replicon cells after G418 selection. These novel adaptive mutations were scored in NS3 (A1065V, C1073S, N1227D, D1431Y, and E1556G), NS4A (I1694T and E1709V), and NS4B (G1871C). The D1431Y mutation alone or combinations of other adaptive mutations introduced into the parental HCV1a replicon construct was observed to differentially enhance either transient or stable expression of replicon. In particular, two replicon mutants VDYG (A1065V, N1227D, D1431Y, and E1556G within NS3) and VDYGRG, VDYG with two additional adaptive mutations (NS4A-K1691R and NS4B-E1726G), displayed robust replication and exhibited no impairment in the susceptibility of replicon activity to various known HCV inhibitors.

Correction: The development of functional mapping by three sex-related loci on the third whorl of different sex types of Carica papaya L.

[This corrects the article DOI: 10.1371/journal.pone.0194605.].

The development of functional mapping by three sex-related loci on the third whorl of different sex types of Carica papaya L.

Carica papaya L. is an important economic crop worldwide and is used as a model plant for sex-determination research. To study the different flower sex types, we screened sex-related genes using alternative splicing sequences (AS-seqs) from a transcriptome database of the three flower sex types, i.e., males, females, and hermaphrodites, established at 28 days before flowering using 15 bacterial artificial chromosomes (BACs) of C. papaya L. After screening, the cDNA regions of the three sex-related loci, including short vegetative phase-like (CpSVPL), the chromatin assembly factor 1 subunit A-like (CpCAF1AL), and the somatic embryogenesis receptor kinase (CpSERK), which contained eight sex-related single-nucleotide polymorphisms (SNPs) from the different sex types of C. papaya L., were genotyped using high-resolution melting (HRM). The three loci were examined regarding the profiles of the third whorl, as described below. CpSVPL, which had one SNP associated with the three sex genotypes, was highly expressed in the male and female sterile flowers (abnormal hermaphrodite flowers) that lacked the fourth whorl structure. CpCAF1AL, which had three SNPs associated with the male genotype, was highly expressed in male and normal hermaphrodite flowers, and had no AS-seqs, whereas it exhibited low expression and an AS-seqs in intron 11 in abnormal hermaphrodite flowers. Conversely, carpellate flowers (abnormal hermaphrodite flowers) showed low expression of CpSVPL and AS-seqs in introns 5, 6, and 7 of CpSERK, which contained four SNPs associated with the female genotype. Specifically, the CpSERK and CpCAF1AL loci exhibited no AS-seq expression in the third whorl of the male and normal hermaphrodite flowers, respectively, and variance in the AS-seq expression of all other types of flowers. Functional mapping of the third whorl of normal hermaphrodites indicated no AS-seq expression in CpSERK, low CpSVPL expression, and, for CpCAF1AL, high expression and no AS-seq expression on XYh-type chromosomes.

Related factors and clinical feature analysis of unexplained early neurological deterioration after intravenous thrombolysis / 第二军医大学学报

Objective To investigate the related factors and clinical features of unexplained early neurological deterioration (END) of acute ischemic stroke (AIS) patients after intravenous thrombolysis. Methods A total of 258 AIS patients, who underwent intravenous thrombolysis treatment within 4.5 h of onset and were registered continuously in Stroke Center of our hospital between Jan. 2016 and Feb. 2018, were included in this study. The unexplained END was defined as the National Institutes of Health stroke scale (NIHSS) score increasing by more than 4 within 24 h of onset compared with that before thrombolysis, with no definite mechanism by imaging examination. The baseline and clinical data were compared between the unexplained END and non-END patients. The clinical features of the AIS patients with unexplained END were analyzed. Results Among the 258 patients enrolled in this study, 243 (94.2%) had no END and 15 (5.8%) had unexplained END. Compared with the patients without END, the proportion of diabetes mellitus in the patients with unexplained END was significantly higher and the door-to-needle time (DNT) was significantly longer (χ2＝6.093, P＝0.048; Z＝2.055, P＝0.040). The NIHSS score of 15 patients with unexplained END before thrombolysis was low (5 [4, 9]). The most common type of trial of Org 10172 in Acute Stroke Treatment (TOAST) classification was small artery occlusion (11 cases, 73.3%). The most common infarction sites were posterior limb of internal capsule (6 cases, 40.0%) and ventromedial pons (6 cases, 40.0%). Conclusion Diabetes mellitus and long DNT may be the risk factors of unexplained END in the patients with AIS after intravenous thrombolysis. Unexplained END usually occurs in the AIS patinets with small artery occlusion and has lower NIHSS score; the common sites of infarction are posterior limb of the internal capsule and ventromedial pons.

YAF2 promotes tumor cell proliferation via targeting cyclin D1 expression / 基础医学与临床

Objective To explore the molecular mechanism by which YY1 associated factor 2(YAF2) up-regulates cyclin D1 expression in tumor cells as well as the effect of YAF2-cyclin D1 regulatory loop on tumor cell prolifera-tion. Methods Overexpression and knockdown experiments combined with Western blot and real-time quantitative PCR were used to detect the expression of YAF2 and cyclin D1;Dual luciferase reporter assay was performed to in-vestigate the effect of YAF2 on cyclin D1 promoter activity;Flow cytometry analysis was carried out to elucidate the effect of YAF2 on cell cycle progression through targeting cyclin D1;Colony formation assay was employed to deter-mine cell proliferation under different YAF2 and cyclin D1 expression level. Results YAF2 upregulated the ex-pression of cyclin D1 at both the mRNA(P<0.05) and protein level;YAF2 activated the promoter activity of cyc-lin D1 (P<0.05);YAF2 silencing increased significantly the proportion of cells in G0/G1phase(P<0.0001) and reduced the proportion of cells in S phase by regulating cyclin D1 (P<0.002); YAF2 facilitated the cell colony formation via targeting cyclin D1(P<0.05). Conclusions In tumor cells,YAF2 promotes the expression of cyclin D1,and enhances cell cycle progression and cell proliferation.

An investigation of laboratory animal resources in Guangdong province / 中国比较医学杂志

Objective A state quo survey of laboratory animal resource in Guangdong province is performed to provide reference data for government management decision-making and market assessment of laboratory animals. Methods We used questionnaires focusing on the laboratory animal facilities with authorization by Guangdong Province Government, which mainly included the production and use of laboratory animals,the qualification of employees and the facilities space. Results The total production and use of laboratory animals(except for the eggs)had been increasing in the last four years. 1.57 million laboratory animals were produced and 0.754 million laboratory animals were used in 2016. There were 2352 employees,roughly the same as in 2015. The facilities space for breeding was 121008 m2,and for animal experiment was 73470 m2,which were rising in the past three years. Conclusions In order to reinforce the industry development of laboratory animals in Guangdong province,some suggestions were given in our study,such as facilitating the application of superiority resource including non-human primate and aquatic laboratory animals,supporting the standardization production of several scarce mice and rats, improving relevant employees' overall level and constructing laboratory animal facilities sharing platform.

Design and implementation of laboratory animal expert consultation system / 中国比较医学杂志

A laboratory animal expert consultation system provides an interactive platform for industry experts and users. Based on intelligent mobile terminal used as the application supporter, the platform combines the internet with laboratory animal to share the experts' knowledge, breaks through temporal and spatial restrictions, and resolves other problems such as poor timeliness of inquire service, knowledge data staticization, and irrational exploitation of internet to gain prompt inquire service. The platform would meet the needs of industry users for real-time aids and bridge the gap between industry experts and users. Thus, the transfer of expert' knowledge is realized in pace with the increasing knowledge resource of this platform to accelerate the transformation of theoretical knowledge into the industry. Our study focuses on the system characteristics, the main frame structure, the design of function module and the system implementation.

Biological parameters and cardiac physiological function of the mice overexpressing human Slit2 gene / 中国实验动物学报

Objective The basic biological, echocardiography and gene sequencing parameters of mice overexpressing Slit2 gene (Slit2-Tg mice) were collected and evaluated, and to provide a reference for the application of Slit2-Tg mice in biomedical research. Methods Slit2-Tg and C57BL/6 J mice were inbred. The genotypes of the mice were determined by a PCR assay. The blood samples were collected for blood routine and biochemical tests. The tissues of main organs were collected for protein expression and pathological analysis. Echocardiography and transcriptome sequencing was carried out for analyzing the heart function and gene expression, respectively. Results The litter size was significantly higher in the Slit2-Tg mice than in C57BL/6 J mice. Human Slit2 gene and protein expressions were detected in the main organs of Slit2-Tg mice. Organ coefficient of spleen was significantly increased in Slit2-Tg mice, but the tissue structure appeared normal. There were significant changes in the counts of erythrocytes, platelets, eosinophils, and biochemistry of glucose, globulin, urea nitrogen, triglycerides, HDL, and atherosclerosis index. Echocardiography showed no significant differences in the morphology and function of the Slit2-Tg hearts except in the left ventricular anterior wall thickness at the end-diastolic state. Compared with the C57BL/6 J mice, 535 genes out of 17513 genes in the Slit2-Tg hearts were increased or decreased, mainly involving 15 biological process or signal transduction pathways. Conclusions This study has collected the biological parameters of Slit2-Tg mice and suggests that this model animal is suitable for the studies of cardiovascular diseases.

The relationship between overexpression of Slit2 and accumulation of amyloid-β in aging mice studied by PCR array / 中国实验动物学报

Objective Previous studies suggested that overerpression of Slit2 results in abnormal Alzheimer's disease-like behavior and cognition impairment in mice. The aim of this study is to investigate the relationship between overerpression of Slit2 and accumulation and clearance of amyloid-β in aging mice by comparing the differential expression of genes for accumulation and clearance of amyloid-β in aging Tg-Slit2 and Tg-2576 mice. Methods 14-month old male C57BL/6, Tg-Slit2 and Tg-2576 mice were used to detect the expression of Aβ1 - 40 and Aβ1 - 42 in brain by immunohistochemistry. Further, the total RNA in the brain of these mice were extracted, identified and inversely transcripted to cDNA, then the cDNA was detected by PCR array. The expression of genes in the brain of Tg-Slit2 and Tg-2576 mice were analyzed. Results Comparing with the Tg-2576 mice in the same age, accumulation of Aβ was not found in the brain of Tg-Slit2 and C57BL/6 mice. The result from PCR array analysis showed that comparing with the same aged C57BL/6 mice, there were 16 up-regulated genes and 8 down-regulated genes in the brain of Tg-Slit2 mice and 14 up-regulated genes and 17 down-regulated genes in the brain of Tg-Slit2 mice. The expression of amyloid beta precursor protein (APP) in the brain of the three group mice was not changed. The expression of presenilin 2 ( Psen2) related with Aβ production was significantly up-regulated in the Tg-2576 mice. In addition, the expression of low density lipoprotein receptor-related protein ( LRP) 6 and 9 were markedly decreased in the Tg-2576 mice. Notably, these genes were not changed in the brain of the aging Tg-Slit2 mice. Conclusions The accumulation of Aβ in the brain are not found in 14-month Tg-Slit2 mice, In addition, different from Tg-2576 mice, the significant changes of expression of Aβ-related genes is not found in the brain of Tg-Slit2 mice.

Coagulatory dysfunction in septic rats / 中国实验动物学报

Objective To investigate the changes of coagulatory function in septic rats induced by cecal ligation and puncture(CLP). Methods Cecal ligation and puncture(CLP)were performed to induce sepsis in SD rats. Coagulation indexes were detected at 8,16 and 48 h after operation, and histopathological changes of the lung, kidney, liver and spleen were examined using HE staining. Results The 12-day survival rate of the CLP-induced septic rats was 30%,with an acute onset and high mortality. In the acute phase of disease development of the CLP rats, the activated partial thromboplastin time(APTT)was prolonged(P<0.05)at 8 h,the prothrombin time(PT)was prolonged at 16 h (P<0.05), the factor XII activity in the endogenous coagulation pathway and the factor VII activity in the extrinsic coagulation pathway showed a transient inhibition, the thrombin time(TT)was prolonged at 48 h(P<0.01), and the content of fibrinogen(FIB)was increased gradually from 16 h(P<0.001). Among the other important coagulation and anticoagulation indexes,the number of platelets(PLT)was decreased gradually from 8 h(P<0.01),while the number of vWF:Ag increased gradually from 8 h(P<0.001). The D-dimer amount gradually increased from 16 h(P<0.05),and the amount of PS:Ag significantly decreased until 48 h(P<0.001). However, there was no significant change in the antithrombin-III(AT-Ⅲ)content. The histopathological examination showed that there are different degrees of damages in the lung,kidney,liver and spleen tissues,but no obvious venous thrombosis and bleeding were found. Conclusions In the acute phase,there is coagulatory dysfunction in the septic rats,however,no histopathological changes such as venous thrombosis and bleeding were observed in the lung,kidney,liver and spleen tissues due to coagulatory dysfunction.

Mutagenesis of Dengue Virus Protein NS2A Revealed a Novel Domain Responsible for Virus-Induced Cytopathic Effect and Interactions between NS2A and NS2B Transmembrane Segments.

The NS2A protein of dengue virus (DENV) has eight predicted transmembrane segments (pTMS1 to -8) and participates in RNA replication, virion assembly, and host antiviral response. However, the roles of specific amino acid residues within the pTMS regions of NS2A during the viral life cycle are not clear. Here, we explore the function of DENV NS2A by introducing a series of alanine substitutions into the N-terminal half (pTMS1 to -4) of the protein in the context of a DENV infectious clone or subgenomic replicon. Six NS2A mutants (NM5, -7, -9, and -17 to -19) around pTMS1 and -2 displayed a novel phenotype showing a >1,000-fold reduction in virus yield, an absence of plaque formation despite wild-type-like replicon activity, and infectious-virus-like particle yields. HEK-293 cells infected with the six NS2A mutant viruses failed to cause a virus-induced cytopathic effect (CPE) by MitoCapture staining, cell proliferation, and lactate dehydrogenase release assays. Sequencing analyses of pseudorevertant viruses derived from lethal-mutant viruses revealed two consensus reversion mutations, leucine to phenylalanine at codon 181 (L181F) within pTMS7 of NS2A and isoleucine to threonine at codon 114 (I114T) within NS2B. The introduction of an NS2A-L181F mutation into the lethal (NM15, -16, -25, and -33) and CPE-defective (NM7, -9, and -19) mutants substantially rescued virus infectivity and virus-induced CPE, respectively, whereas the NS2B-L114T mutation rescued the NM16, -25, and -33 mutants. In conclusion, the results revealed the essential roles of the N-terminal half of NS2A in RNA replication and virus-induced CPE. Intramolecular interactions between pTMSs of NS2A and intermolecular interactions between the NS2A and NS2B proteins were also implicated.IMPORTANCE The characterization of the N-terminal (current study) and C-terminal halves of DENV NS2A is the most comprehensive mutagenesis study to date to investigate the function of NS2A during the flaviviral life cycle. A novel region responsible for virus-induced cytopathic effect (CPE) within pTMS1 and -2 of DENV NS2A was identified. Revertant genetics studies implied unexpected relationships between various pTMSs of DENV NS2A and NS2B. These results provide comprehensive information regarding the functions of DENV NS2A and the specific amino acids and transmembrane segments responsible for these functions. The positions and properties of the rescuing mutations were also revealed, providing important clues regarding the manner in which intramolecular or intermolecular interactions between the pTMSs of NS2A and NS2B regulate virus replication, assembly/secretion, and virus-induced CPE. These results expand the understanding of flavivirus replication. The knowledge may also facilitate studies of pathogenesis and novel vaccine and antiflaviviral drug development.

High-frequency echocardiography for assessment of regional wall motion abnormality and cardiac function in mice with myocardial infarction / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the value of high-frequency echocardiography in assessing cardiac structure and function in a mouse model of myocardial infarction.</p><p><b>METHODS</b>Twenty-five C57BL/6 mice were randomly divided into sham-operated group (n=10) and myocardial infarction model group (n=15) established by ligation of the left anterior descending artery. The cardiac structure, regional wall motion and cardiac function of mice were examined with pulsed wave Doppler (PWD), tissue Doppler imaging (TDI), EKV and M-mode echocardiography 3 days before and at 1 week after the operation. The histological changes and myocardial structure of the heart were observed at 1 week after the operation.</p><p><b>RESULTS</b>High-frequency echocardiography and HE staining detected obvious myocardial infarction in the mice in the model group. Compared with the sham-operated mice, the mice with myocardial infarction showed significant left ventricular expansion, obvious thinning of the ventricular wall, and significantly decreased ventricular systolic function and diastolic function with regional wall motion abnormality and ventricular remodeling.</p><p><b>CONCLUSION</b>s 2D-type echocardiography combined with M-mode, PWD, TDI and EKVTM for allows accurate and sensitive detection of the loci and severity of myocardial infarction to provide important evidence for clinical diagnosis and treatment of myocardial infarction.</p>