Access to gem-Difluoroalkenes via Organic Photoredox-Catalyzed gem-Difluoroallylation of Alkyl Iodides.

An organic photoredox-catalyzed gem-difluoroallylation of α-trifluoromethyl alkenes with alkyl iodides via C-F bond cleavage for the synthesis of gem-difluoroalkene derivatives is reported. This transition-metal-free transformation utilized a readily available organic dye 4CzIPN as the sole photocatalyst and employed a common chemical N,N,N',N'-tetramethylethylenediamine as the radical activator of alkyl iodides via halogen-atom transfer. In addition, a variety of iodides, including primary, secondary, and tertiary alkyl iodides, were tolerated and provided good to high yields.

Effect of SiO2 addition on NH4HSO4 decomposition and SO2 poisoning over V2O5-MoO3/TiO2-CeO2 catalyst.

The deposition of NH4HSO4 and the poisoning effect of SO2 on SCR catalyst are the main obstacles that restrict the industrial application of CeO2-doped SCR catalysts. In this work, deposited NH4HSO4 decomposition behavior and SO2 poisoning over V2O5-MoO3/TiO2 catalysts modified with CeO2 and SiO2 were investigated. By the means of characterization analysis, it was found that the addition of SiO2 into VMo/Ti-Ce had an impact on the interaction existed between catalyst surface atoms and NH4HSO4. Temperature-programmed methods and in situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments indicated that the doping of SiO2 promoted the decomposition of deposited NH4HSO4 on VMo/Ti-Ce catalyst surface by reducing the thermal stability of NH4HSO4 and enhancing the NH4HSO4 reactivity with NO in low temperature. And this improvement may be the reason for the better catalytic activity than VMo/Ti-Ce in the case of NH4HSO4 deposition. Accompanied with cerium sulfate species generated over catalyst surface, the conversion of SO2 to SO3 was inhibited in SiCe mixed catalyst. The addition of SiO2 could promote the decomposition of cerium sulfate, which may be a potential strategy to enhance the resistance of SO2 poisoning over CeO2-modifed catalysts.

Transformation and removal of ammonium sulfate aerosols and ammonia slip from selective catalytic reduction in wet flue gas desulfurization system.

Selective catalytic reduction (SCR) denitration may increase the emission of NH4+ and NH3. The removal and transformation characteristics of ammonium sulfate aerosols and ammonia slip during the wet flue gas desulfurization (WFGD) process, as well as the effect of desulfurization parameters, were investigated in an experimental system equipped with a simulated SCR flue gas generation system and a limestone-based WFGD system. The results indicate that the ammonium sulfate aerosols and ammonia slip in the flue gas from SCR can be partly removed by slurry scrubbing, while the entrainment and evaporation of desulfurization slurry with accumulated NH4+ will generate new ammonium-containing particles and gaseous ammonia. The ammonium-containing particles formed by desulfurization are not only derived from the entrainment of slurry droplets, but also from the re-condensation of gaseous ammonia generated by slurry evaporation. Therefore, even if the concentration of NH4+ in the desulfurization slurry is quite low, a high level of NH4+ was still contained in the fine particles at the outlet of the scrubber. When the accumulated NH4+ in the desulfurization slurry was high enough, the WFGD system promoted the conversion of NH3 to NH4+ and increased the additional emission of primary NH4+ aerosols. With the decline of the liquid/gas ratio and flue gas temperature, the removal efficiency of ammonia sulfate aerosols increased, and the NH4+ emitted from entrainment and evaporation of the desulfurization slurry decreased. In addition, the volatile ammonia concentration after the WFGD system was reduced with the decrease of the NH4+ concentration and pH values of the slurry.

CmTCP20 Plays a Key Role in Nitrate and Auxin Signaling-Regulated Lateral Root Development in Chrysanthemum.

Lateral root (LR) formation and development play a vital role in plant development by permitting the establishment of branched root systems. It is well known that nutrient availability controls LR development. Moreover, LR development is fine-tuned by a myriad of hormonal signals. Many transcription factors (TFs) participate in LR development. Here, we discuss the TFs involved in the nitrate and auxin signaling pathways and how these function in the regulation of LR formation and development in chrysanthemum. AtTCP20 is a plant-specific TF, which can modulate LR development in response to nitrate. The roles of CmTCP20 in LR development were identified by overexpression in chrysanthemum and heterologous expression in Arabidopsis. Overexpression of CmTCP20 significantly increased the number and average length of LRs compared with the wild type in chrysanthemum and Arabidopsis. We also found that CmTCP20 positively influenced auxin accumulation in the LRs at least partly by improving auxin biosynthesis, transport and response, thereby promoting LR development. Moreover, we found that CmTCP20 interacts with an auxin response factor, CmARF8, which also can be induced by nitrate and combined to proximal sites in the upstream promoter region of CmCYCB1;1 to positively regulate the cell cycle. The CmTCP20-CmARF8 heterodimer links nitrate and auxin signaling and converts cell-cycle signals to regulate LR initiation and growth.

Engineering a sensitive visual-tracking reporter system for real-time monitoring phosphorus deficiency in tobacco.

Plant phosphorus (P) diagnosis is widely used for monitoring P status and guiding P fertilizer application in field conditions. The common methods for predicting plant response to P are time- and labour-consuming chemical measurements of the extractable soil P and plant P concentrations. In this study, we successfully generated a visual reporter system in tobacco (Nicotiana tabacum L.) to monitor plant P status by expressing of a Purple gene (Pr) isolated from cauliflower (Brassica oleracea var botrytis) driven by the promoter (Pro) of OsPT6, a P-starvation-induced rice gene. The leaves of OsPT6pro::Pr (PT6pro::Pr) transgenic tobacco continuously turned into dark purple with the increase of duration and severity of P deficiency, and recovered rapidly to basal green colour upon resupply of P. The expression of several anthocyanin biosynthesis involving genes was strongly activated in the transgenic tobacco in comparison to wild type under P-deficient condition. Such additive purple colour was not detected by deficiencies of other major- and micronutrients or stresses of salt, drought and cold. There was an extremely high correlation between P concentration and anthocyanin accumulation in the transgenic tobacco leaves. Using a hyperspectral sensing technology, P concentration in the leaves of transgenic plants could be predicted by the reflectance spectra at 554 nm wavelength with approximately 0.16 as the threshold value of the P deficiency. Taken together, the colour-based visual reporter system could be specifically and readily used for monitoring the plant P status by naked eyes and accurately assessed by spectral reflectance.

Prefrontal projections modulate recurrent circuitry in the insular cortex to support short-term memory.

Short-term memory (STM) maintains information during a short delay period. How long-range and local connections interact to support STM encoding remains elusive. Here, we tackle the problem focusing on long-range projections from the medial prefrontal cortex (mPFC) to the anterior agranular insular cortex (aAIC) in head-fixed mice performing an olfactory delayed-response task. Optogenetic and electrophysiological experiments reveal the behavioral importance of the two regions in encoding STM information. Spike-correlogram analysis reveals strong local and cross-region functional coupling (FC) between memory neurons encoding the same information. Optogenetic suppression of mPFC-aAIC projections during the delay period reduces behavioral performance, the proportion of memory neurons, and memory-specific FC within the aAIC, whereas optogenetic excitation enhances all of them. mPFC-aAIC projections also bidirectionally modulate the efficacy of STM-information transfer, measured by the contribution of FC spiking pairs to the memory-coding ability of following neurons. Thus, prefrontal projections modulate insular neurons' functional connectivity and memory-coding ability to support STM.

A molecular framework underlying low-nitrogen-induced early leaf senescence in Arabidopsis thaliana.

Nitrogen (N) deficiency causes early leaf senescence, resulting in accelerated whole-plant maturation and severely reduced crop yield. However, the molecular mechanisms underlying N-deficiency-induced early leaf senescence remain unclear, even in the model species Arabidopsis thaliana. In this study, we identified Growth, Development and Splicing 1 (GDS1), a previously reported transcription factor, as a new regulator of nitrate (NO3-) signaling by a yeast-one-hybrid screen using a NO3- enhancer fragment from the promoter of NRT2.1. We showed that GDS1 promotes NO3- signaling, absorption and assimilation by affecting the expression of multiple NO3- regulatory genes, including Nitrate Regulatory Gene2 (NRG2). Interestingly, we observed that gds1 mutants show early leaf senescence as well as reduced NO3- content and N uptake under N-deficient conditions. Further analyses indicated that GDS1 binds to the promoters of several senescence-related genes, including Phytochrome-Interacting Transcription Factors 4 and 5 (PIF4 and PIF5) and represses their expression. Interestingly, we found that N deficiency decreases GDS1 protein accumulation, and GDS1 could interact with Anaphase Promoting Complex Subunit 10 (APC10). Genetic and biochemical experiments demonstrated that Anaphase Promoting Complex or Cyclosome (APC/C) promotes the ubiquitination and degradation of GDS1 under N deficiency, resulting in loss of PIF4 and PIF5 repression and consequent early leaf senescence. Furthermore, we discovered that overexpression of GDS1 could delay leaf senescence and improve seed yield and N-use efficiency (NUE) in Arabidopsis. In summary, our study uncovers a molecular framework illustrating a new mechanism underlying low-N-induced early leaf senescence and provides potential targets for genetic improvement of crop varieties with increased yield and NUE.

New insights into the role of chrysanthemum calcineurin B-like interacting protein kinase CmCIPK23 in nitrate signaling in Arabidopsis roots.

Nitrate is an important source of nitrogen and also acts as a signaling molecule to trigger numerous physiological, growth, and developmental processes throughout the life of the plant. Many nitrate transporters, transcription factors, and protein kinases participate in the regulation of nitrate signaling. Here, we identified a gene encoding the chrysanthemum calcineurin B-like interacting protein kinase CmCIPK23, which participates in nitrate signaling pathways. In Arabidopsis, overexpression of CmCIPK23 significantly decreased lateral root number and length and primary root length compared to the WT when grown on modified Murashige and Skoog medium with KNO3 as the sole nitrogen source (modified MS). The expression of nitrate-responsive genes differed significantly between CmCIPK23-overexpressing Arabidopsis (CmCIPK23-OE) and the WT after nitrate treatment. Nitrate content was significantly lower in CmCIPK23-OE roots, which may have resulted from reduced nitrate uptake at high external nitrate concentrations (≥ 1 mM). Nitrate reductase activity and the expression of nitrate reductase and glutamine synthase genes were lower in CmCIPK23-OE roots. We also found that CmCIPK23 interacted with the transcription factor CmTGA1, whose Arabidopsis homolog regulates the nitrate response. We inferred that CmCIPK23 overexpression influences root development on modified MS medium, as well as root nitrate uptake and assimilation at high external nitrate supply. These findings offer new perspectives on the mechanisms by which the chrysanthemum CBL interacting protein kinase CmCIPK23 influences nitrate signaling.

A Link Between Mitochondrial Dysfunction and the Immune Microenvironment of Salivary Glands in Primary Sjogren's Syndrome.

Background: Primary Sjogren's syndrome (pSS) is a slowly progressive, inflammatory autoimmune disease characterized by lymphocytic infiltration into salivary and lacrimal glands. It becomes more recognized that morphology alterations of epithelial mitochondria are involved in altered cellular bioenergetics in pSS patients. The integrated analysis of the mitochondrial role in the pathogenesis and aberrant immune microenvironment in pSS remains unknown. Methods: The mitochondria-related genes and gene expression data were downloaded from the MitoMiner, MitoCarta, and NCBI GEO databases. We performed novel transcriptomic analysis and constructed a network between the mitochondrial function and immune microenvironment in pSS-salivary glands by computer-aided algorithms. Subsequently, real-time PCR was performed in clinical samples in order to validate the bioinformatics results. Histological staining and transmission electron microscopy (TEM) were further studied on labial salivary gland samples of non-pSS and pSS patients characterized for mitochondria-related phenotypic observation in the different stages of the disease. Results: The bioinformatic analysis revealed that the expression of several mitochondria-related genes was altered in pSS. Quantitative real-time PCR showed that four hub genes, CD38, CMPK2, TBC1D9, and PYCR1, were differentially expressed in the pSS clinical samples. These hub genes were associated with the degree of immune cell infiltration in salivary glands, the mitochondrial respiratory chain complexes, mitochondrial metabolic pathway in gluconeogenesis, TCA cycle, and pyruvate/ketone/lipid/amino acid metabolism in pSS. Clinical data revealed that the gene expression of fission (Fis1, DRP1, and MFF) and fusion (MFN1, MFN2, and OPA1) was downregulated in pSS samples, consistent with the results from the public validation database. As the disease progressed, cytochrome c and Bcl-2 proteins were regionally distributed in salivary glands from pSS patients. TEM revealed cytoplasmic lipid droplets and progressively swollen mitochondria in salivary epithelial cells. Conclusion: Our study revealed cross talk between mitochondrial dysfunction and the immune microenvironment in salivary glands of pSS patients, which may provide important insights into SS clinical management based on modulation of mitochondrial function.

Identification of Methicillin-Resistant Staphylococcus Aureus From Methicillin-Sensitive Staphylococcus Aureus and Molecular Characterization in Quanzhou, China.

To distinguish Methicillin-Resistant Staphylococcus aureus (MRSA) from Methicillin-Sensitive Staphylococcus aureus (MSSA) in the protein sequences level, test the susceptibility to antibiotic of all Staphylococcus aureus isolates from Quanzhou hospitals, define the virulence factor and molecular characteristics of the MRSA isolates. MRSA and MSSA Pfam protein sequences were used to extract feature vectors of 188D, n-gram and 400D. Weka software was applied to classify the two Staphylococcus aureus and performance effect was evaluated. Antibiotic susceptibility testing of the 81 Staphylococcus aureus was performed by the Mérieux Microbial Analysis Instrument. The 65 MRSA isolates were characterized by Panton-Valentine leukocidin (PVL), X polymorphic region of Protein A (spa), multilocus sequence typing test (MLST), staphylococcus chromosomal cassette mec (SCCmec) typing. After comparing the results of Weka six classifiers, the highest correctly classified rates were 91.94, 70.16, and 62.90% from 188D, n-gram and 400D, respectively. Antimicrobial susceptibility test of the 81 Staphylococcus aureus: Penicillin-resistant rate was 100%. No resistance to teicoplanin, linezolid, and vancomycin. The resistance rate of the MRSA isolates to clindamycin, erythromycin and tetracycline was higher than that of the MSSAs. Among the 65 MRSA isolates, the positive rate of PVL gene was 47.7% (31/65). Seventeen sequence types (STs) were identified among the 65 isolates, and ST59 was the most prevalent. SCCmec type III and IV were observed at 24.6 and 72.3%, respectively. Two isolates did not be typed. Twenty-one spa types were identified, spa t437 (34/65, 52.3%) was the most predominant type. MRSA major clone type of molecular typing was CC59-ST59-spa t437-IV (28/65, 43.1%). Overall, 188D feature vectors can be applied to successfully distinguish MRSA from MSSA. In Quanzhou, the detection rate of PVL virulence factor was high, suggesting a high pathogenic risk of MRSA infection. The cross-infection of CA-MRSA and HA-MRSA was presented, the molecular characteristics were increasingly blurred, HA-MRSA with typical CA-MRSA molecular characteristics has become an important cause of healthcare-related infections. CC59-ST59-spa t437-IV was the main clone type in Quanzhou, which was rare in other parts of mainland China.

Novel Aspects of Nitrate Regulation in Arabidopsis.

Nitrogen (N) is one of the most essential macronutrients for plant growth and development. Nitrate (NO3 -), the major form of N that plants uptake from the soil, acts as an important signaling molecule in addition to its nutritional function. Over the past decade, significant progress has been made in identifying new components involved in NO3 - regulation and starting to unravel the NO3 - regulatory network. Great reviews have been made recently by scientists on the key regulators in NO3 - signaling, NO3 - effects on plant development, and its crosstalk with phosphorus (P), potassium (K), hormones, and calcium signaling. However, several novel aspects of NO3 - regulation have not been previously reviewed in detail. Here, we mainly focused on the recent advances of post-transcriptional regulation and non-coding RNA (ncRNAs) in NO3 - signaling, and NO3 - regulation on leaf senescence and the circadian clock. It will help us to extend the general picture of NO3 - regulation and provide a basis for further exploration of NO3 - regulatory network.

Transient Delay-Period Activity of Agranular Insular Cortex Controls Working Memory Maintenance in Learning Novel Tasks.

Whether transient or sustained neuronal activity during the delay period underlies working memory (WM) has been debated. Here, we report that transient, but not sustained, delay-period activity in mouse anterior agranular insular cortex (aAIC) plays a dominant role in maintaining WM information during learning of novel olfactory tasks. By optogenetic screening over 12 brain regions, we found that suppressing aAIC activity markedly impaired olfactory WM maintenance during learning. Single-unit recording showed that odor-selective aAIC neurons with predominantly transient firing patterns encoded WM information. Both WM task performance and transient-neuron proportion were enhanced and reduced by activating and suppressing the delay-period activity of the projection from medial prefrontal cortex (mPFC) to aAIC. The ability of mice to resist delay-period distractors also correlated with an increased percentage of transient neurons. Therefore, transient, but not sustained, aAIC neuronal activity during the delay period is largely responsible for maintaining information while learning novel WM tasks.

Proteomic profiling of root system development proteins in chrysanthemum overexpressing the CmTCP20 gene.

Plant root systems ensure the efficient absorption of water and nutrients and provide anchoring into the soil. Although root systems are a highly plastic set of traits that vary both between and among species, the basic root system morphology is controlled by inherent genetic factors. TCP20 has been identified as a key regulator of root development in plants, and yet its underlying mechanism has not been fully elucidated, especially in chrysanthemum. We found that overexpression of the CmTCP20 gene promoted both adventitious and lateral root development in chrysanthemum. To get further insight into the molecular mechanisms controlling root system development, we conducted a study employing tandem mass tag proteomic to characterize the differential root system development proteomes from CmTCP20-overexpressing and wild-type chrysanthemum root samples. Of the proteins identified, 234 proteins were found to be differentially abundant (>1.5-fold cut off, p < 0.05) in CmTCP20-overexpressing versus wild-type chrysanthemum root samples. Functional enrichment analysis indicated that the CmTCP20 gene may participate in "phytohormone signal transduction". Our findings provide a valuable perspective on the mechanisms of both adventitious and lateral root development via CmTCP20 modulation at the proteome level in chrysanthemum.

Active information maintenance in working memory by a sensory cortex.

Working memory is a critical brain function for maintaining and manipulating information over delay periods of seconds. It is debated whether delay-period neural activity in sensory regions is important for the active maintenance of information during the delay period. Here, we tackle this question by examining the anterior piriform cortex (APC), an olfactory sensory cortex, in head-fixed mice performing several olfactory working memory tasks. Active information maintenance is necessary in these tasks, especially in a dual-task paradigm in which mice are required to perform another distracting task while actively maintaining information during the delay period. Optogenetic suppression of neuronal activity in APC during the delay period impaired performance in all the tasks. Furthermore, electrophysiological recordings revealed that APC neuronal populations encoded odor information in the delay period even with an intervening distracting task. Thus, delay activity in APC is important for active information maintenance in olfactory working memory.

New seco-milbemycins from Streptomyces bingchenggensis: fermentation, isolation and structure elucidation.

Two new seco-milbemycins have been isolated and characterized from the Streptomyces bingchenggensis. On the basis of detailed spectroscopic analysis and comparison with the reported data of milbemycin beta(14), their structures were established to be the seco-milbemycins of milbemycin beta(14). However, milbemycin beta(14) and the two new seco-milbemycins were not converted to each other during purification by silica gel column or storage in the MeOH extract at room temperature. The two new seco-milbemycins are the first discovered from milbemycin-producing microorganisms. They may play an important role in understanding and perfecting the proposed biosynthesis pathways of milbemycins.

[Hepatitis B virus X protein suppressing adriamycin-induced apoptosis of HepG2 cells].

OBJECTIVES: To investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells. METHODS: HBx gene fragment was amplified from subtype adr HBV plasmid by PCR, and inserted into Hind III and Kpn I sites of green fluorescent protein (GFP) eukaryotic expression vector pEGFP-C1 to construct recombinant pGFP/HBx. The pEGFP-C1 and pGFP-HBx were introduced into HepG2 cells by Lipofectamine 2000 to obtain HepG2 cells expressing GFP. GFP-HBx fusion protein was selected using G418. The expression of HBx gene was demonstrated by RT-PCR analysis. HepG2, HepG2/GFP and HepG2/GFP-HBx cells were treated with adriamycin (2.5 microg/ml), and apoptosis of the cells was determined by their morphological changes, trypan blue exclusion, and flow cytometry analysis. RESULTS: Under a fluorescence microscope, visible expression of GFP and GFP-HBx fusion proteins were observed in HepG2/GFP and HepG2/GFP-HBx cells, even after growing over 70 generations. RT-PCR analysis showed that HBx gene was expressed in HepG2/GFP-HBx cells. Trypan blue exclusion showed adriamycin induced time-dependent cell death in HepG2 and HepG2/GFP cells while no significant cell death was observed in HepG2/GFP-HBx cells. Flow cytometry analysis showed that apoptosis rates in HepG2/GFP-HBx (3.94%) cells were significantly lower than those in HepG2 (59.03%) and HepG2/GFP cells (61.38%) at 36 hours after the adriamycin treatment (P < 0.01). No significant differences of apoptosis rates of HepG2/GFP-HBx (3.94%) and of the untreated cells (2.12%, 2.78%, 2.55%) (P > 0.05) were observed. CONCLUSION: A HepG2 cell line expressing GFP and GFP-HBx fusion proteins was successfully established. HBV X protein blocks adriamycin-induced apoptosis of these HepG2 cells.

Phosphate transporter OsPht1;8 in rice plays an important role in phosphorus redistribution from source to sink organs and allocation between embryo and endosperm of seeds.

Phosphorus (P) redistribution from source to sink organs within plant is required for optimizing growth and development under P deficient condition. In this study, we knocked down expression of a phosphate transporter gene OsPht1;8 (OsPT8) selectively in shoot and/or in seed endosperm by RNA-interference using RISBZ1 and GluB-1 promoter (designate these transgenic lines as SSRi and EnSRi), respectively, to characterize the role of OsPT8 in P redistribution of rice. In comparison to wild type (WT) and EnSRi lines, SSRi lines under P deficient condition accumulated more P in old blades and less P in young blades, corresponding to attenuated and enriched transcripts of P-responsive genes in old and young blades, respectively. The ratio of total P in young blades to that in old blades decreased from 2.6 for WT to 0.9-1.2 for SSRi lines. During the grain-filling stage, relative to WT, SSRi lines showed the substantial decrease of total P content in both endosperm and embryo, while EnSRi lines showed 40-50% decrease of total P content in embryo but similar P content in endosperm. Taken together, our results demonstrate that OsPT8 plays a critical role in redistribution of P from source to sink organs and P homeostasis in seeds of rice.

[Effects of Chinese herbs for cool-moistening and freeing collaterals on serum gastrin and surface electrogastrogram in patients of diabetes mellitus with gastroparesis].

OBJECTIVE: To explore the effect of Chinese herbs (CH) for cool-moistening and freeing collaterals on gastro-dynamic disturbance in patients of diabetes mellitus type 2 with gastroparesis (DM-GP). METHODS: Fifty-three patients of DM-GP were enrolled and treated with CH (n = 28) and Cisapride (n = 25) respectively for 4 weeks, the changes of gastrin and electro-gastrogram (EGG) before and after treatment were observed. RESULTS: After treatment, the EGG improved significantly, showing the rhythm significantly improved, and level of serum gastrin lowered significantly, as compared with those before treatment, the difference was significant (P<0.01), but insignificant difference was found between the two groups. Fifteen patients in each group were followed-up afar stopping medication for 3 months, recurrence occurred in 1 patient of CH treated group, and 2 patients of Cisapride treated group. No adverse reaction was found in the rest patients. CONCLUSION: CH could obviously improve the gastro-intestinal motility and hormones abnormality.

Medial prefrontal activity during delay period contributes to learning of a working memory task.

Cognitive processes require working memory (WM) that involves a brief period of memory retention known as the delay period. Elevated delay-period activity in the medial prefrontal cortex (mPFC) has been observed, but its functional role in WM tasks remains unclear. We optogenetically suppressed or enhanced activity of pyramidal neurons in mouse mPFC during the delay period. Behavioral performance was impaired during the learning phase but not after the mice were well trained. Delay-period mPFC activity appeared to be more important in memory retention than in inhibitory control, decision-making, or motor selection. Furthermore, endogenous delay-period mPFC activity showed more prominent modulation that correlated with memory retention and behavioral performance. Thus, properly regulated mPFC delay-period activity is critical for information retention during learning of a WM task.

[Hepatitis B virus X protein suppresses adriamycin-induced apoptosis of hepatocellular carcinoma cells and expression of p53 and PTEN].

OBJECTIVE: To investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells and the expressions of p53 and PTEN. METHODS: HepG2, HepG2/GFP, and HepG2/GFP-HBx cells were treated with adriamycin (2.5 microg/ml), and the apoptotic cell death was determined by observing the morphological changes and flow cytometry. The expressions of p53 and PTEN mRNA in the 3 cells were detected by RT-PCR, and the expressions of p53 and PTEN protein were analyzed by Western blotting. RESULTS: Adriamycin induced significant cell death in HepG2 and HepG2/GFP cells, which became rounded, shrunk, and detached after the treatment; but no significant cell death occurred in HepG2/GFP-HBx cells. Flow cytometry analysis showed that the apoptotic rate was significantly lower in HepG2/GFP-HBx cells (3.94%) than in HepG2 (59.03%) and HepG2/GFP cells (61.38%) at 36 h after the treatment (P<0.001), while no significant difference was observed between HepG2/GFP-HBx (3.94%) and the control cells (2.12%, 2.78%, and 2.55%) (P>0.05). RT-PCR showed lowered expression of PTEN mRNA in HepG2/GFP-HBx cells as compared to that in HepG2 and HepG2/GFP cells, while no significant difference was noted in p53 mRNA. Western blot analysis showed that PTEN protein decreased while p53 protein remain unchanged in HepG2/GFP-HBx cells. CONCLUSION: HBx suppresses adriamycin-induced apoptosis of HepG2 cells and PTEN expression. The inhibitory effect of HBx on the cell apoptosis may be related to the inhibition of p53-PTEN pathway.