Biomass pellets are undergoing fast deployment widely in the world, including China. To this stage, there were limited studies on the emissions of various organic pollutants from the burning of those pellets. In addition to parent polycyclic aromatic hydrocarbons, oxygenated PAHs (oPAHs) have been received increased concerns. In this study, emission factors of oPAHs (EFoPAHs) were measured for two types of pellets made from corn straw and pine wood, respectively. Two combustion modes with (mode II) and without (mode I) secondary side air supply in a modern pellet burner were investigated. For the purpose of comparison, EFoPAHs for raw fuels combusted in a traditional cooking stove were also measured. EFoPAHs were 348±305 and 396±387 µg/kg in the combustion mode II for pine wood and corn straw pellets, respectively. In mode I, measured EFoPAHs were 77.7±49.4 and 189±118 µg/kg, respectively. EFs in mode II were higher (2–5 times) than those in mode I mainly due to the decreased combustion temperature under more excess air. Compared to EFoPAHs for raw corn straw and pine wood burned in a traditional cooking stove, total EFoPAHs for the pellets in mode I were significantly lower (p < 0.05), likely due to increased combustion efficiencies and change in fuel properties. However, the difference between raw biomass fuels and the pellets burned in mode II was not statistically significant. Taking both the increased thermal efficiencies and decreased EFs into consideration, substantial reduction in oPAH emission can be expected if the biomass pellets can be extensively used by rural residents.
Oxygenated PAHs; Biomass Pellets; Emission Factor; Emission Reduction
Hepatitis E virus (HEV) causes both the endemic and epidemic spread of acute hepatitis in many parts of the world. HEV open reading frame 3 (ORF3) encodes a 13-kDa multifunctional protein (vp13) that is essential for HEV infection of animals. The exact role of vp13 in HEV infection remains unclear. In this study, vp13 was found to enhance interferon (IFN) production induced by poly(I · C), a synthetic analog of double-stranded RNA. Poly(I · C) treatment induced a higher level of IFN-β mRNA in HeLa cells stably expressing vp13 than in control cells. Using a luciferase reporter construct driven by the IFN-β promoter, we demonstrated that vp13 enhanced retinoic acid-inducible gene I (RIG-I)-dependent luciferase expression. This enhancement was found to be due to both an increased level of RIG-I protein and its activation. The levels of both endogenous and exogenous RIG-I were increased by vp13 by extension of the half-life of RIG-I. Additionally, vp13 interacts with the RIG-I N-terminal domain and enhances its K63-linked ubiquitination, which is essential for RIG-I activation. Analysis of vp13 deletion constructs suggested that the C-terminal domain of vp13 was essential for the enhancement of RIG-I signaling. In HEV-infected hepatoma cells, wild-type HEV led to a higher level of RIG-I and more poly(I · C)-induced IFN-β expression than did ORF3-null mutants. Analysis of vp13 from four HEV genotypes showed that vp13 from genotype I and III strains boosted RIG-I signaling, while vp13 from genotype II and IV strains had a minimal effect. These results indicate that vp13 enhances RIG-I signaling, which may play a role in HEV invasion.
IMPORTANCE Hepatitis E virus (HEV) is a significant pathogen causing hepatitis in many parts of the world, yet it is understudied compared with other viral hepatitis pathogens. Here we found that the HEV open reading frame 3 product, vp13, enhances interferon induction stimulated by a synthetic analog of double-stranded RNA. This enhancement may play a role in HEV invasion, as vp13 is essential for HEV infection in vivo. The results of this study provide insights into virus-cell interactions during HEV infection. In addition to revealing its possible roles in HEV interference with cellular signaling, these results suggest that the second half of the vp13 sequence can be ligated into the genomes of attenuated live viruses to induce an innate immune response for better protective immunity, as well as a marker for differentiation of vaccinated animals from those infected with the corresponding wild-type viruses.
Tubeimoside-1 (TBMS1) is a natural compound isolated from tubeimoside, which has been widely used as a traditional Chinese herbal medicine. The purpose of the present study is to investigate the anti-tumor effect and the underling mechanism of TBMS1 on glioma cancer cells.
The MTT assay was performed to evaluate the effect of TBMS1 on glioma cell proliferation. The fluorescent microscopy and flow cytometry analysis were performed to evaluate the effect of TBMS1 on glioma cell apoptosis. The Western blot analysis was used to evaluate the protein change.
TBMS1 inhibited glioma cancer cell proliferation in a dose- and time-dependent manner. Fluorescent microscopy and flow cytometry analysis demonstrated that TBMS1 induced glioma cell apoptosis in a concentration-dependent manner. Western blotting showed that TBMS1 induced apoptosis by increasing the expression of Bax and downregulating the level of Bcl-2. Furthermore, we found that TBMS1 induced apoptosis by increasing the concentration of reactive oxygen species through the release of Cytochrome C and activation of Caspase-3.
These findings indicate that TBMS1 may be developed as a possible therapeutic agent for the management of glioma.
Tubeimoside-1; glioma; proliferation; apoptosis
We propose a novel two-step procedure to combine epidemiological data obtained from diverse sources with the aim to quantify risk factors affecting the probability that an individual develops certain disease such as cancer. In the first step we derive all possible unbiased estimating functions based on a group of cases and a group of controls each time. In the second step, we combine these estimating functions efficiently in order to make full use of the information contained in data. Our approach is computationally simple and flexible. We illustrate its efficacy through simulation and apply it to investigate pancreatic cancer risks based on data obtained from the Connecticut Tumor Registry, a population-based case-control study, and the Behavioral Risk Factor Surveillance System which is a state-based system of health surveys.
Spatial epidemiology; spatial point process; estimating equation
Recent debate about prostate specific antigen (PSA)-based testing for prostate cancer screening among older men has rarely considered the cost of screening.
We assembled a population-based cohort of male Medicare beneficiaries aged 66–99 years who had never been diagnosed with prostate cancer at the end of 2006 (n = 94,652) and followed them for three years to assess the cost of PSA screening and downstream procedures (biopsy, pathology, and hospitalization due to biopsy complications) at both the national and the hospital referral region (HRR) level.
Approximately 51.2% of men received PSA screening tests during the three-year period, with 2.9% undergoing biopsy. The annual expenditures on prostate cancer screening by the national fee-for-service Medicare program were $447 million in 2009 US dollars. The mean annual screening cost at the HRR level ranged from $17 to $62 per beneficiary. Downstream biopsy-related procedures accounted for 72% of the overall screening costs and varied significantly across regions. Compared with men residing in HRRs that were in the lowest quartile for screening expenditures, men living in the highest HRR quartile were significantly more likely to be diagnosed with prostate cancer of any stage [incidence rate ratio (IRR) = 1.20, 95% confidence interval (CI): 1.07–1.35] and localized cancer (IRR = 1.30, 95% CI: 1.15–1.47). The IRR for regional/metastasized cancer was also elevated although not statistically significant (IRR = 1.31, 95% CI: 0.81–2.11).
Medicare prostate cancer screening-related expenditures are substantial, vary considerably across regions, and are positively associated with rates of cancer diagnosis.
Prostate cancer; prostate specific antigen; screening; stage; cost
The uncertainty in emission estimation is strongly associated with the variation in emission factor which could be influenced by a variety of factors, like fuel property, stove type, fire management and even methods used in measurements. The impacts of these factors were usually complicated and often interacted with each other. In the present study, controlled burning experiments were conducted to investigate the influence of fuel mass load, air supply and burning rate on the emission of carbonaceous particulate matter (PM) from indoor corn straw burning. Their impacts on PM size distribution were also studied. The results showed that EFs of PM (EFPM), organic carbon (EFOC) and element carbon (EFEC) was independent of the fuel mass load. The differences among them under different burning rates or air supply amounts were also found to be insignificant (p > 0.05) in the tested circumstances. PM from the indoor corn straw burning was dominated by fine PM, and PM with diameter less than 2.1 μm contributed about 86.4±3.9% of the total. The size distribution of PM was also influenced by the burning rate and changed air supply conditions. On average, EFPM, EFOC and EFEC for corn straw burned in a residential cooking stove were 3.84±1.02, 0.846±0.895 and 0.391±0.350 g/kg, respectively. EFPM, EFOC and EFEC were found to be positively correlated with each other, but they were not significantly correlated with EF of co-emitted CO, suggesting a special attention should be paid to the use of CO acting as a surrogate for other incomplete pollutants.
indoor corn straw burning; emission factor; size distribution; influencing factor
Emission factors (EFs) of parent polycyclic aromatic (pPAHs), nitrated PAHs (nPAHs), and oxygenated PAHs (oPAHs) were measured for indoor corn straw burned in a cooking brick stove in both normal and controlled burning conditions. EFs of total 28 pPAHs, 6 nPAHs and 4 oPAHs were 7.9±3.4, 6.5±1.6×10-3, and 6.1±1.4×10-1 mg/kg, respectively. By controlling the burning conditions, it was found that the influence of fuel charge size on EFs of the pPAHs and derivatives was insignificant. Measured EFs increased significantly in a fast burning mainly because of the oxygen deficient atmosphere formed in the stove chamber with a small volume. In both restricted and enhance air supply conditions, EFs of pPAHs, nPAHs and oPAHs were significantly higher than those measured in normal burning conditions. Though EFs varied in different burning conditions, the composition profiles and calculated isomer ratios were similar without significant differences. The results from the stepwise regression model showed that fuel burning rate, air supply amount, and modified combustion efficiency were three most significant influencing factors, explaining 72-85% of the total variations.
polycyclic aromatic hydrocarbons; PAH derivatives; emission factor; influencing factor; indoor crop straw burning
Controlled combustion experiments were conducted to investigate the influence of fuel charge size, moisture, air ventilation and burning rate on the emission factors (EFs) of carbonaceous particulate matter, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives from residential wood combustion in a typical brick cooking stove. Measured EFs were found to be independent of fuel charge size, but increased with increasing fuel moisture. Pollution emissions from a normal burning under an adequate air supply condition were the lowest for most pollutants, while more pollutants were emitted when the oxygen deficient atmosphere was formed in stove chamber during fast burning. The impact of these 4 factors on particulate matter size distribution was also studied. Modified combustion efficiency and the four investigated factors explained 68, 72, and 64% of total variations in EFs of PM, organic carbon, and oxygenated PAHs, respectively, but only 36, 38 and 42% of the total variations in EFs of elemental carbon, pPAHs and nitro-PAHs, respectively.
residential wood combustion; influencing factor; carbonaceous particulate matter; polycyclic aromatic hydrocarbons; emission factor
Studies have reported inconsistent results concerning the existence of associations of folate intake and serum folate levels with prostate cancer risk. This study sought to summarise the evidence regarding these relationships using a dose–response meta-analysis approach.
In January 2014, we performed electronic searches of PubMed, Embase, and the Cochrane Library to identify studies examining the effect of folate on the incidence of prostate cancer. Only prospective studies that reported effect estimates with 95% confidence intervals (CIs) of the incidence of prostate cancer for more than 2 categories of folate were included.
Overall, we included 10 prospective studies reporting data on 202,517 individuals. High dietary folate intake had little or no effect on prostate cancer risk (risk ratio [RR] = 1.02; 95% CI = 0.95–1.09; P = 0.598). The dose–response meta-analysis suggested that a 100 μg per day increase in dietary folate intake has no significant effect on the risk of prostate cancer (RR = 1.01; 95% CI = 0.99–1.02; P = 0.433). However, high serum folate levels were associated with an increased risk of prostate cancer (RR = 1.21; 95% CI = 1.05–1.39; P = 0.008). The dose–response meta-analysis indicated that a 5 nmol/L increment of serum folate levels was also associated with an increased risk of prostate cancer (RR = 1.04; 95% CI = 1.00–1.07; P = 0.042).
Our study indicated that dietary folate intake had little or no effect on prostate cancer risk. However, increased serum folate levels have potentially harmful effects on the risk of prostate cancer.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2458-14-1326) contains supplementary material, which is available to authorized users.
Folate; Prostate cancer; Dose–response; Meta-analysis
Environmental health risk assessors are challenged to understand and incorporate new data streams as the field of toxicology continues to adopt new molecular and systems biology technologies. Systematic screening reviews can help risk assessors and assessment teams determine which studies to consider for inclusion in a human health assessment. A tool for systematic reviews should be standardized and transparent in order to consistently determine which studies meet minimum quality criteria prior to performing in-depth analyses of the data. The Systematic Omics Analysis Review (SOAR) tool is focused on assisting risk assessment support teams in performing systematic reviews of transcriptomic studies. SOAR is a spreadsheet tool of 35 objective questions developed by domain experts, focused on transcriptomic microarray studies, and including four main topics: test system, test substance, experimental design, and microarray data. The tool will be used as a guide to identify studies that meet basic published quality criteria, such as those defined by the Minimum Information About a Microarray Experiment standard and the Toxicological Data Reliability Assessment Tool. Seven scientists were recruited to test the tool by using it to independently rate 15 published manuscripts that study chemical exposures with microarrays. Using their feedback, questions were weighted based on importance of the information and a suitability cutoff was set for each of the four topic sections. The final validation resulted in 100% agreement between the users on four separate manuscripts, showing that the SOAR tool may be used to facilitate the standardized and transparent screening of microarray literature for environmental human health risk assessment.
Emission characterization of polycyclic aromatic hydrocarbons (PAHs) from residential combustion of crop residues, woody material, coal, and biomass pellets in domestic stoves in rural China are compared in term of emission factors (EFs), influencing factors, composition profiles, isomer ratios and phase distributions. The EFs of PAHs vary by two orders of magnitude among fuel types suggesting that a detailed fuel categorization is useful in the development of an emission inventory and potential in emission abatement of PAHs by replacing dirty fuels with relatively cleaner ones. The influence of fuel moisture in biomass burning is non-linear. Biofuels with very low moisture display relatively high emissions as do fuels with very high moisture. Bituminous coals and brushwood yield relatively large fractions of high molecular PAHs. The emission factor of Benzo(a)pyrene equivalent quantity for raw bituminous coal is as high as 52 mg/kg, which is 1–2 orders of magnitude higher than the other fuels. For source diagnosis, high molecular weight isomers are more informative than low molecular weight ones and multiple ratios could be used together whenever possible.
Distant metastasis is one of the most common causes for failure in treatment of advanced NSCLC, and it is a key factor to determine the patients’ prognosis. This study aims to screen the microRNAs associated with non-small cell lung cancer metastasis, so as to provide theoretical basis for investigating their roles in non-small cell lung cancer metastasis. In this study, the fluorescent transfected human non-small cell lung cancer cell lines H460 developed tumors subcutaneously, which were then in situ transplanted into the left lung of nude mice to obtain the tissue specimens of primary tumor and metastatic tumor. The differentially expressed microRNAs associated with non-small cell lung cancer metastasis were identified using the microRNA microarray and real-time quantitative polymerase chain reaction (RT-PCR) analysis, and bioinformatics analysis of the microRNAs was performed. The microarray analysis results revealed that 17 microRNAs with up-regulated expression and 7 with down-regulated expression between the non-small cell lung cancer metastatic primary loci and the non-metastatic primary loci (Group A), while 20 microRNAs with up-regulated expression (ratio > 1.5 times, P < 0.05) and 16 with down-regulated expression (ratio < 0.65 times, P < 0.05) between the non-small cell lung cancer metastatic loci and the metastatic primary loci (Group B). RT-PCR validation and bioinformatics analysis of some microRNAs identified 2 microRNAs with up-regulated expression, miR-10b and miR-144, and 3 microRNAs with down-regulated expression, miR-9, miR-31 and miR-34b in Group A; and 4 microRNAs with down-regulated expression, miR-25, miR-92a, miR-202 and miR-326 in Group B, which may be mediated by transcription factors activator protein 1 (AP-1), p53, STATs and NF-κB, regulate cell development, proliferation and cycle, DNA and RNA metabolism and signal transduction pathway, and promote tumor growth and metastasis through the effects on target genes like RARβ, RASSF1 and E2F-1. In conclusion, there are differences in microRNA expression between the non-small cell lung cancer metastatic and non-metastatic tissues, which provides experimental basis for exploring the mechanism of non-small cell lung cancer metastasis and provides a potential idea for molecular diagnosis and treatment, as well as prognosis.
Non-small cell lung cancer; metastasis; microRNA; microarray; nude mouse model; target gene
mRNA display is a powerful technique that allows for covalent coupling of a translated protein with its coding mRNA. The resulting conjugation between genotype and phenotype can be used for the efficient selection and identification of peptides or proteins with desired properties from an mRNA-displayed peptide or protein library with high diversity. This protocol outlines the principle of mRNA display and the detailed procedures for the synthesis of mRNA-protein fusions. Some special considerations for library construction, generation and purification are discussed.
mRNA display; covalent coupling of mRNA and protein; genotype-phenotype conjugation; in vitro protein selection; high diversity
Fathead minnow and zebrafish are among the most intensively studied fish species in environmental toxicogenomics. To aid the assessment and interpretation of subtle transcriptomic effects from treatment conditions of interest, better characterization and understanding are needed for natural variation in gene expression among fish individuals from lab cultures. Leveraging the transcriptomics data from a number of our toxicogenomics studies conducted over the years, we conducted a meta-analysis of nearly 600 microarrays generated from the ovary tissue of untreated, reproductively mature fathead minnow and zebrafish samples. As expected, there was considerable batch-to-batch transcriptomic variation; this “batch-effect” appeared to differentially impact subsets of fish transcriptomes in a nonsystematic way. Temporally more closely spaced batches tended to share a greater transcriptomic similarity among one another. The overall level of within-batch variation was quite low in fish ovary tissue, making it a suitable system for studying chemical stressors with subtle biological effects. The observed differences in the within-batch variability of gene expression, at the levels of both individual genes and pathways, were probably both technical and biological. This suggests that biological interpretation and prioritization of genes and pathways targeted by experimental conditions should take into account both their intrinsic variability and the size of induced transcriptional changes. There was significant conservation of both the genomes and transcriptomes between fathead minnow and zebrafish. The high degree of conservation offers promising opportunities in not only studying fish molecular responses to environmental stressors by a comparative biology approach, but also effective sharing of a large amount of existing public transcriptomics data for developing toxicogenomics applications.
mRNA display is a powerful in vitro selection technique that can be applied towards the identification of peptides or proteins with desired properties. The physical conjugation between a protein and its own RNA presents unique challenges in manipulating the displayed proteins in an RNase free environment. This protocol outlines the generation of synthetic peptide and natural proteome libraries as well as the steps required for generation of mRNA-protein fusion libraries, in vitro selection, and regeneration of the selected sequences. The selection procedures for the identification of Ca2+ dependent calmodulin binding proteins from synthetic peptide and natural proteome libraries are presented.
mRNA display; genotype-phenotype conjugation; in vitro selection; synthetic combinatorial peptide library; natural proteome library; conditional protein-protein interaction
Flowering phenology is central to the ecology and evolution of most flowering plants. In highly-specific nursery pollination systems, such as that involving fig trees (Ficus species) and fig wasps (Agaonidae), any mismatch in timing has serious consequences because the plants must balance seed production with maintenance of their pollinator populations. Most fig trees are found in tropical or subtropical habitats, but the dioecious Chinese Ficus tikoua has a more northerly distribution. We monitored how its fruiting phenology has adapted in response to a highly seasonal environment. Male trees (where fig wasps reproduce) had one to three crops annually, whereas many seed-producing female trees produced only one fig crop. The timing of release of Ceratosolen fig wasps from male figs in late May and June was synchronized with the presence of receptive figs on female trees, at a time when there were few receptive figs on male trees, thereby ensuring seed set while allowing remnant pollinator populations to persist. F. tikoua phenology has converged with those of other (unrelated) northern Ficus species, but there are differences. Unlike F. carica in Europe, all F. tikoua male figs contain male flowers, and unlike F. pumila in China, but like F. carica, it is the second annual generation of adult wasps that pollinate female figs. The phenologies of all three temperate fig trees generate annual bottlenecks in the size of pollinator populations and for female F. tikoua also a shortage of fig wasps that results in many figs failing to be pollinated.
The aim of the present study was to clarify the association between lipid metabolism and the atherosclerosis in early-stage chronic renal failure at the molecular level and to explore the efficacy of decorin on chronic renal failure. Sprague Dawley rats receiving 5/6 nephrectomy and Sham surgery were divided into control and experimental groups. Sprague Dawley rats receiving 5/6 nephrectomy were divided into control and experimental groups, and the experimental group was further subdivided into rats receiving treatment with fibroblasts (FBs) transfected either with empty vector and with a decorin (DCN) gene. The dynamic levels of triglyceride (TG), total cholesterol (T-Ch) and total phospholipid (T-PL) were detected on the 10th, 30th and 60th days. The body weight, blood lipid levels, renal function and renal tissue were observed after four weeks, and transforming growth factor-βl and protein expression was detected by immunohistochemistry. In total, 4 weeks after treatment, the DCN expression in the renal tissue of rats treated with DCN-transfected FBs was significantly increased compared to that in the control rats. The results showed that the levels of the three lipids in the aortic arches were slightly elevated on the 10th day compared with those in the control group, and the TG level was significantly increased on the 30th day. The levels of T-Ch, TG and T-PL in the aortic arches were significantly elevated on the 60th day. The TG and T-Ch levels in the plasma and aortic tissues of Sprague Dawley rats receiving 5/6 nephrectomy without any treatment and after receiving treatment with FBs transfected with empty vector were significantly increased compared with those in the control group. The increased T-Ch and decreased T-PL levels in the erythrocyte membrane increased the rigidity of the erythrocyte and decreased erythrocyte deformability. In conclusion, highly expressed DCN mitigated renal fibrosis and thus delayed renal failure as well as mitigating the abnormal lipid metabolism of the chronic renal failure.
lipid; renal failure; decorin; gene therapy
Nongonococcal urethritis (NGU) is the most common male reproductive tract syndrome. Ureaplasmas spp. including U. urealyticum and U. parvum, have been increasingly reported to be implicated in NGU. However, there are still many contradictions about their pathogenic role in NGU.
The goals of this study were to evaluate the association of Ureaplasmas spp. with NGU, and to compare the prevalence of Ureaplasmas spp. infection in China relative to the world average.
A systematic review and meta-analysis was conducted following standard guidelines for meta-analysis. The quality of included studies was assessed by Newcastle-Ottawa scale.
A total of seven studies involving 1,507 NGU patients and 1,223 controls were eligible for meta-analysis. There was no significant difference in the Ureaplasma spp. positive rate between the NGU and control groups. However, the U. urealyticum positive rate was significantly higher in NGU patients compared to controls; the U. parvum positive rate was significantly higher in controls compared to NGU patients. Furthermore, within the NGU patient group, the positive rate of U. urealyticum was significantly higher than that of U. parvum, whereas within the control group, the opposite trend was observed. Compared to the world average, a significantly higher positive rate of Ureaplasma spp. was observed in both the NGU and control groups in China.
Our analysis supports that U. urealyticum, but not U. parvum, is an etiological agent in NGU. More detailed studies of these two species in China and the world could contribute to a better understanding of the epidemiology and pathogenesis, and facilitate the development of better strategies for treatment and prevention of NGU.
Background and objective
Mirror-like intracranial aneurysms (MirAn) occur symmetrically at the corresponding intracranial arteries and are a subgroup of multiple intracranial aneurysms. The aim of this study was to analyze the risk factors, treatment, and prognosis of MirAn.
We retrospectively analyzed 43 cases of MirAn diagnosed between January 2000 and December 2009. The control groups comprised patients with non-mirror-like multiple aneurysms (nMirAn) and single aneurysms (SingAn). Sex, age, localization of MirAn, hypertension, diabetes, smoking, and rupture were identified as potential risk factors for MirAn.
The male to female ratio of the MirAn patients was 1.0:5.1, which was significantly different from that of the nMirAn patients (1.0:1.9, P=0.037) and SingAn patients (1.0:1.3, P<0.001). There was no difference in age (P=0.8741), smoking (P=0.301), diabetes (P=0.267), or hypertension (P=0.874) between the MirAn and nMirAn patients. The aneurysms in 28 MirAn patients (65.1%) involved the internal carotid-posterior communicating arteries; in these patients, the rupture risk was significantly higher for larger aneurysms compared with smaller aneurysms (P<0.05).
More women suffered from MirAn than nMirAn or SingAn. The most common MirAn sites were the internal carotid-posterior communicating arteries. Our results suggest that MirAn was not associated with age, smoking, hypertension, or diabetes.
women’s health; mirror-like intracranial aneurysm; retrospective analysis; clinical feature
The parasite Toxoplasma gondii controls tissue-specific nitric oxide (NO), thereby augmenting virulence and immunopathology through poorly-understood mechanisms. We now identify TgMAPK1, a Toxoplasma mitogen-activated protein kinase (MAPK), as a virulence factor regulating tissue-specific parasite burden by manipulating host interferon (IFN)-γ-mediated inducible nitric oxide synthase (iNOS). Toxoplasma with reduced TgMAPK1 expression (TgMAPK1lo) demonstrated that TgMAPK1 facilitates IFN-γ-driven p38 MAPK activation, reducing IFN-γ-generated NO in an MKK3-dependent manner, blunting IFN-γ-mediated parasite control. TgMAPK1lo infection in wild type mice produced ≥ten-fold lower parasite burden versus control parasites with normal TgMAPK1 expression (TgMAPK1con). Reduced parasite burdens persisted in IFN-γ KO mice, but equalized in normally iNOS-replete organs from iNOS KO mice. Parasite MAPKs are far less studied than other parasite kinases, but deserve additional attention as targets for immunotherapy and drug discovery.
iNOS; MAPK; Toxoplasma gondii; virulence
High altitude environments cause the human body to undergo a series of pathological, physiological and biochemical changes, which have a certain effect on drug pharmacokinetics. The objective of the present study was to observe changes in factors affecting pharmacokinetics in rats following acute exposure to high altitude and return to low altitude. A total of 21 male Wistar rats were randomly assigned to three groups. The rats in group A were maintained at low altitude in Shanghai, 55 m above sea level; those in group B were acutely exposed to high altitude in Maqu, Gansu, 4,010 m above sea level; and those in group C were acutely exposed to high altitude and then returned to low altitude. Blood was collected from the orbit for the analysis of significant biochemical indicators and from the abdominal aorta for blood gas analysis. Brain, lung and kidney tissues were removed to observe pathological changes. In group B, the pH, buffer base (BB), base excess (BE), total carbon dioxide content (ctCO2), oxygen saturation of arterial blood (sO2), oxygen tension of arterial blood (pO2), serum sodium (Na+) concentration, lactate dehydrogenase (LDH) activity and total protein (TP) level were significantly reduced, and the carbon dioxide tension of arterial blood (pCO2), serum chloride (Cl−) concentration, serum total bilirubin (TBIL) level and alkaline phosphatase (ALP) activity were significantly increased compared with those in group A (P<0.05). In group C, the pH, BB, BE, sO2, pO2, hemoglobin (Hb) level, serum Na+ concentration, LDH activity and TP level were significantly reduced, and the pCO2, serum Cl− concentration, alanine transaminase activity, TBIL and urea levels were significantly increased (P<0.05) compared with those in group A. The Hb and ALP levels in group C were significantly lower than those in group B (P<0.05); and the TP, TBIL and urea levels in group C were significantly higher than those in group B (P<0.05). Pathological observation revealed that the alveolar wall was hyperemic, edematous and incrassate, the alveolar epithelium was hyperplastic and infiltrated with neutrophilic granulocytes and the alveolar septum was widened; brain neurons were edematous with enlarged perivascular spaces, and hippocampal neurons were metamorphic and karyopyknotic; and kidney mesangial cells were hyperplastic, both following acute exposure to high altitude and after returning to low altitude. In conclusion, blood gas indices, biochemical indicators and functions of the heart, liver, kidney were significantly changed, and marked pathological changes occurred in the brain, liver and kidney following acute exposure to high altitude and also after returning to low altitude. These changes are likely to seriously affect the pharmacokinetics of drugs.
acute exposure to high altitude; blood gas analysis; biochemical indicators; pathological changes; Wistar rats
DNA methylation and demethylation regulate many crucial biological processes in mammals and are linked to many diseases. Active DNA demethylation is believed to be catalyzed by TET proteins and a putative DNA decarboxylase that may share some similarities in sequence, structure and catalytic mechanism with isoorotate decarboxylase (IDCase) that catalyzes decarboxylation of 5caU to U in fungi. We report here the structures of wild-type and mutant IDCases from Cordyceps militaris and Metarhizium anisopliae in apo form or in complexes with 5caU, U, and an inhibitor 5-nitro-uracil. IDCases adopt a typical (β/α)8 barrel fold of the amidohydrolase superfamily and function as dimers. A Zn2+ is bound at the active site and coordinated by four strictly conserved residues, one Asp and three His. The substrate is recognized by several strictly conserved residues. The functional roles of the key residues at the active site are validated by mutagenesis and biochemical studies. Based on the structural and biochemical data, we present for the first time a novel catalytic mechanism of decarboxylation for IDCases, which might also apply to other members of the amidohydrolase superfamily. In addition, our biochemical data show that IDCases can catalyze decarboxylation of 5caC to C albeit with weak activity, which is the first in vitro evidence for direct decarboxylation of 5caC to C by an enzyme. These findings are valuable in the identification of potential DNA decarboxylase in mammals.
catalytic mechanism; crystal structure; DNA demethylation; DNA decarboxylation; decarboxylase; pyrimidine metabolism; thymidine salvage pathway
The effect of mouse resistin on hepatic insulin resistance in vivo and in vitro, and its possible molecular mechanism were examined. Focusing on liver glycogen metabolism and gluconeogenesis, which are important parts of glucose metabolism, in primary cultures of rat hepatocytes we found that glycogen content was significantly lower (P<0.05) after treatment with recombinant murine resistin only in the presence of insulin plus glucose stimulation. Protein levels of factors in the insulin signaling pathway involved in glycogen synthesis were examined by Western blot analysis, with the only significant change observed being the level of phosphorylated (at Ser 9) glycogen synthase kinase-3β (GSK-3β) (P<0.001). No differences in the protein levels for the insulin receptor β (IRβ), insulin receptor substrates (IRS1 and IRS2), phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) or their phosphorylated forms were observed between control and resistin treated primary rat hepatocytes. In a mouse model with high liver-specific expression of resistin, fasting blood glucose levels and liver glycogen content changed. Fasting blood glucose levels were significantly higher (P<0.001) in the model mice, compared to the control mice, while the glycogen content of the liver tissue was about 60% of that of the control mice (P<0.05). The gluconeogenic response was not altered between the experimental and control mice. The level of phosphorylated GSK-3β in the liver tissue was also decreased (P<0.05) in the model mice, consistent with the results from the primary rat hepatocytes. Our results suggests that resistin reduces the levels of GSK-3β phosphorylated at Ser 9 leading to impaired hepatic insulin action in primary rat hepatocytes and in a mouse model with high liver-specific expression of resistin.
PMID: 23860320 CAMSID: cams3833
Resistin; Insulin resistance; Glycogen synthase kinase-3β (GSK-3β); Liver
Atherosclerosis is a typical complex multi-factorial disease and many molecules at different levels and pathways were involved in its development. Some studies have investigated the dysregulation in atherosclerosis at mRNA, miRNA or DNA methylation level, respectively. However, to our knowledge, the studies that integrated these data and revealed the abnormal networks of atherosclerosis have not been reported. Using microarray technology, we analyzed the omics data in atherosclerosis at mRNA, miRNA and DNA methylation levels. Our results demonstrated that the global DNA methylation and expression of miRNA/mRNA were significantly decreased in atherosclerotic plaque than in normal vascular tissue. The interaction network constructed using the integrative data revealed many genes, cellular processes and signaling pathways which were widely considered to play crucial roles in atherosclerosis and also revealed some genes, miRNAs or signaling pathways which have not been investigated in atherosclerosis until now (e.g. miR-519d and SNTB2). Moreover, the overall protein ubiquitination in atherosclerotic plaque was significantly increased. The proteasome activity was increased early but decreased in advanced atherosclerosis. Our study revealed many classic and novel genes and miRNAs involved in atherosclerosis and indicated the effects of ubiquitin-proteasome system on atherosclerosis might be closely related to the course of atherosclerosis. However, the efficacy of proteasome inhibitors in the treatment of atherosclerosis still needs more research.
MicroRNAs (miRNAs) are small, short noncoding RNAs that modulate the expression of numerous genes by targeting their mRNA. Numerous abnormal miRNA expression patterns are observed in various human malignancies, and certain miRNAs can act as oncogenes or tumor suppressors. Astrocytoma, the most common neuroepithelial cancer, represents the majority of malignant brain tumors in humans. In our previous studies, we found that the downregulation of miR-181b-5p in astrocytomas is associated with a poor prognosis. The aim of the present study was to investigate the functional role of miR-181b-5p and its possible target genes. miR-181b-5p was significantly downregulated in astrocytoma specimens, and the reduced expression of miR-181b-5p was inversely correlated with the clinical stage. The ectopic expression of miR-181b-5p inhibited proliferation, migration and invasion and induced apoptosis in astrocytoma cancer cells in vitro. The NOVA1 (neuro-oncological ventral antigen 1) gene was further identified as a novel direct target of miR-181b-5p. Specifically, miR-181b-5p bound directly to the 3'-untranslated region (UTR) of NOVA1 and suppressed its expression. In clinical specimens, NOVA1 was overexpressed, and its protein levels were inversely correlated with miR-181b-5p expression. Furthermore, the changing level of NOVA1 was significantly associated with a poor survival outcome. Similar to restoring miR-181b-5p expression, downregulating NOVA1 inhibited cell growth, migration and invasion. Overexpression of NOVA1 reversed the inhibitory effects of miR-181b-5p. Our results indicate that miR-181b-5p is a tumor suppressor in astrocytoma that inhibits tumor progression by targeting NOVA1. These findings suggest that miR-181b-5p may serve as a novel therapeutic target for astrocytoma.