With the proliferation of the Internet of Things(IoT),various services are emerging with totally different features and requirements,which cannot be supported by the current fifth generation of mobile cellular network...With the proliferation of the Internet of Things(IoT),various services are emerging with totally different features and requirements,which cannot be supported by the current fifth generation of mobile cellular networks(5G).The future sixth generation of mobile cellular networks(6G)is expected to have the capability to support new and unknown services with changing requirements.Hence,in addition to enhancing its capability by 10–100 times compared with 5G,6G should also be intelligent and open to adapt to the ever-changing services in the IoT,which requires a convergence of Communication,Computing and Caching(3C).Based on the analysis of the requirements of new services for 6G,this paper identifies key enabling technologies for an intelligent and open 6G network,all featured with 3C convergence.These technologies cover fundamental and emerging topics,including 3C-based spectrum management,radio channel construction,delay-aware transmission,wireless distributed computing,and network self-evolution.From the detailed analysis of these 3C-based technologies presented in this paper,we can see that although they are promising to enable an intelligent and open 6G,more efforts are needed to realize the expected 6G network.展开更多
It is well known that an unhealthy lifestyle is a major risk factor for metabolic diseases,while in recent years,accumulating evidence has demonstrated that the gut microbiome and its metabolites also play a crucial r...It is well known that an unhealthy lifestyle is a major risk factor for metabolic diseases,while in recent years,accumulating evidence has demonstrated that the gut microbiome and its metabolites also play a crucial role in the onset and development of many metabolic diseases,including obesity,type 2 diabetes,nonalcoholic fatty liver disease,cardiovascular disease and so on.Numerous microorganisms dwell in the gastrointestinal tract,which is a key interface for energy acquisition and can metabolize dietary nutrients into many bioactive substances,thus acting as a link between the gut microbiome and its host.The gut microbiome is shaped by host genetics,immune responses and dietary factors.The metabolic and immune potential of the gut microbiome determines its significance in host health and diseases.Therefore,targeting the gut microbiome and relevant metabolic pathways would be effective therapeutic treatments for many metabolic diseases in the near future.This review will summarize information about the role of the gut microbiome in organism metabolism and the relationship between gut microbiome-derived metabolites and the pathogenesis of many metabolic diseases.Furthermore,recent advances in improving metabolic diseases by regulating the gut microbiome will be discussed.展开更多
AIM:To investigate maspin expression in tumorigenesis and progression of gastric cancer and to explore its relevant molecular mechanisms.METHODS:Formalin-fixed and paraffin-embedded tissues from normal mucosa (n=182),...AIM:To investigate maspin expression in tumorigenesis and progression of gastric cancer and to explore its relevant molecular mechanisms.METHODS:Formalin-fixed and paraffin-embedded tissues from normal mucosa (n=182), dysplasia (n=69), cancer (n=l13) of the stomach were studied for maspin expression by immunohistochemistry. Microvessel density (MVD) in gastric cancer was labeled using anti-CD34 antibody. Maspin expression was compared with clinical parameters and MVD of tumors. Caspase-3 expression was also detected in gastric carcinoma by immunohistochemistry. The relationship between Caspase-3 and maspin expression was concerned as well.RESULTS:The positive rates of maspin expression were 79.8% (145/182), 75.4%(52/69) and 50.4%(57/113) in normal mucosa, dysplasia and cancer of the stomach,respectively.Cancer less frequently expressed maspin than normal mucosa and dysplasia (P<0.05).Maspin expression showed a significantly negative association with invasive depth, metastasis, Lauren's and Nakamura's classification (P<0.05),but not with tumor size, Borrmann's classification,growth pattern or TNIVl staging (P>0.05). The positive rate of Caspase-3 was significantly lower in gastric cancer than in normal gastric mucosa (P<0.05,32.7% vs 50.4%). It was noteworthy that maspin expression was negatively correlated with MVD, but positively correlated with expression of Caspase-3 in gastric cancer (P<0.05).CONCLUSION:Down-regulated maspin expression is a late molecular event in gastric carcinogenesis. Reduced expression of maspin contributes to progression of gastric cancer probably by inhibiting cell adhesion, enhandng cell mobility,decreasing cell apoptosis and facilitating angiogenesis.Additionally altered expression of maspin underlies the molecular mechanism of differentiation of gastric cancer and supports the different histogenetic pathways of intestinal and diffuse gastric cancers. Maspin expression can be considered as an effective and objective marker to reveal biological behaviors of gastric cancer.展开更多
The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland fo...The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland for monitoring, protection and utilization. Wetland construction and distribution in the basin were analyzed based on multi-source data including field investigation data, CBERS remote sensing data and other thematic data provided by 3S technology. The results are （1） the total area of wetlands is 209,322.26 hm^2, accounting for 6.37% of the total land area of the basin. The wetlands are mainly dominated by natural wetland, with artificial wetland occupying only 1.09% of the wetland area; marsh wetland is the principal part of natural wetland, dominated by Kobresia littledalei swampy meadow which is distributed in the river source area and upstream of Chali, Damshung and Medro Gongkar counties. The ratio and type of wetlands in different counties differ significantly, which are widely distributed in Chali and Damshung counties （accounting for 62% of the total wetland area）. （2） The concentrated vertical distribution of wetlands is at an elevation of 3600-5100 m The wetlands are widely distributed throughout the Yarlung Zangbo River Valley from river source to river mouth into the Yarlung Zangbo River. Marsh wetland is dominant in the source area and upstream of the river, with the mosaic distribution of lakes, Kobresia litUedalei and Carex moorcroftii swampy meadow, shrubby swamp and river; as for the middle-down streams, the primary types are river wetland and flooded wetland. The distribution is in a mosaic pattern of river, Kobresia humilis and Carex moorcroftii swampy meadow, Phragmites australis and subordinate grass marsh, flooded wetland and artificial wetland.展开更多
Pulmonary fibrosis, a progressive chronic disease with a high mortality rate, has limited treatment options. Currently, lung transplantation remains the only effective treatment. Here we report that a small RNA, HJT-s...Pulmonary fibrosis, a progressive chronic disease with a high mortality rate, has limited treatment options. Currently, lung transplantation remains the only effective treatment. Here we report that a small RNA, HJT-sRNA-m7, from a Chinese herbal medicine Hong Jing Tian(HJT, RHODIOHAE CRENULATAE RADIX ET RHIZOMA, Rhodiola crenulata) can effectively reduce the expressions of fibrotic hallmark genes and proteins both in alveolar in vitro and in mouse lung tissues in vivo. We also discovered over one hundred oil-soluble chemicals from HJT decoctions, most of which are found in lipid extracts from other Chinese herbals decoctions, including Pu Gong Ying(PGY, TARAXACI HERBA, Taraxacum mongolicum), Chuan Xin Lian(CXL, changed to "ANDROGRAPHIS HERBA, Andrographis paniculata"), and Jin Yin Hua(JYH, lonicera japonica or Honeysuckle). We identified the active component in these decoctions as two forms of phosphocholines, PC(18:0/18:2) and PC(16:0/18:2). These PCs potentially could form liposomes with small RNAs to enter human alveolar and gastric cells. Our experimental results suggest an unprecendent lipid complex route through which botanic small RNA can enter human bodies.Our results provide an innovative treatment strategy for oral delivery of siRNAs as therapeutic medication.展开更多
AIM: To investigate the polymorphisms of interleukin-18 (IL-18) gene promoters, and to disclose whether such polymorphisms are associated with susceptibility to chronic hepatitis B in Chinese Han population. METHODS: ...AIM: To investigate the polymorphisms of interleukin-18 (IL-18) gene promoters, and to disclose whether such polymorphisms are associated with susceptibility to chronic hepatitis B in Chinese Han population. METHODS: Using polymerase chain reaction with sequence specific primers (PCR-SSP) method, the single nucleotide polymorphisms (SNPs) of the promoter region of IL-18 gene at position -607 and -137 were detected in 231 patients with chronic hepatitis B and 300 normal controls. RESULTS: Allele C at position -607 in the promoter of IL-18 gene was detected in 48.7% of normal controls and 51.9% of patients, while allele A at position -607 was detected in 51.3% of normal controls and 48.1% of patients. The frequencies of -607CC, -607 CA and -607AA genotypes in normal controls were 22.0%, 53.3% and 24.7% respectively and in chronic hepatitis B patients were 26.8%, 50.2% and 23.0% respectively. Allele G at position -137 in the promoter of IL-18 gene was detected in 82.3% of normal controls and 88.5% of chronic hepatitis B patients, while allele C at position -137 was detected in 17.7% of normal controls and 11.5% of patients. The frequencies of -137GG, GC and CC genotype were 67.3%, 30.0% and 2.7% in normal controls respectively, while in chronic hepatitis B patients were 78.8%, 19.5% and 1.7% respectively. The frequency of-137GG genotype in chronic hepatitis B groups was significantly higher than that in normal controls (x2=8.55, P=0.003 <0.05), whereas the frequencies of -607C/-137C and -607A/-137C haplotypes in chronic hepatitis B groups were significantly lower than that in normal controls. The association between genotypes of IL-18 promoter region polymorphisms and HBV copies showed that the frequency of -607AA genotype in high HBV-DNA copies groups was lower than that in low HBV-DNA copies groups (x2=6.03, P=0.014 <0.05). CONCLUSION: The polymorphisms of the promoter region of IL-18 gene at position -607 and -137 are closely associated with susceptibility to chronic hepatitis B. The people with allele C at posit展开更多
DNA methylation plays an important role in gene expression regulation during biological development and tissue differentiation in plants. This study adopted methylation-sensitive Amplified fragment length polymorphism...DNA methylation plays an important role in gene expression regulation during biological development and tissue differentiation in plants. This study adopted methylation-sensitive Amplified fragment length polymorphism （AFLP） to compare the levels of DNA cytosine methylation at CCGG sites in tassel, bracteal leaf, and ear leaf from maize inbred lines, 18 White and 18 Red, respectively, and also examined specific methylation patterns of the three tissues. Significant differences in cytosine methylation level among the three tissues and the same changing tendency in two inbred lines were detected. Both MSAP （methylation sensitive amplification polymorphism） ratio and full methylation level were the highest in bracteal leaf, and the lowest in tassel. Meanwhile, different methylation levels were observed in the same tissue from the inbred lines, 18 White and 18 Red. Full methylation of internal cytosine was the dominant type in the maize genome. The differential methylation patterns in the three tissues were observed. In addition, sequencing of nine differentially methylated fragments and the subsequent blast search revealed that the cytosine methylated 5 ＇ -CCGG-3 ＇ sequences were distributed in repeating sequences, in the coding and noncoding regions. Southern hybridization was used to verify the methylation polymorphism. These results clearly demonstrated the power of the MSAP technique for large-scale DNA methylation detection in the maize genome, and the complexity of DNA methylation change during plant growth and development. The different methylation levels may be related to specific gene expression in various tissues.展开更多
AIM: To investigate the possible association of G→A single nucleotide polymorphism (SNP) at the -1082 position of interleukin (IL)-10 promoter with susceptibility to esophageal squamous cell carcinoma (ESCC) and gast...AIM: To investigate the possible association of G→A single nucleotide polymorphism (SNP) at the -1082 position of interleukin (IL)-10 promoter with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) in a population of a high incidence region of North China.METHODS: IL-10-G1082A promoter SNP was genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) in 355 cancer patients (203ESCC and 152 GCA) and 443 healthy controls.RESULTS: Smoking significantly increased the risk of ESCC and GCA development (the age and sex adjusted OR = 1.42and 2.64, 95%CI = 1.11-1.81 and 1.46-4.76, respectively).Similarly, family history of upper gastrointestinal cancer (UGIC) significantly increased the risk of developing ESCC and GCA (the age and sex adjusted OR = 1.44 and 3.10,95%CI = 1.18-1.75 and 1.94-4.97, respectively). The A/A, A/G and G/G genotype frequencies of IL-10-G1082A were 60.3%, 37.0% and 2.7% in healthy controls, 57.6%,39.9% and 2.5% in ESCC and 61.2%, 36.8% and 2.0% in GCA patients, respectively. The frequencies of A and G alleles were 78.8% and 21.2% in healthy controls, 77.6%and 22.4% in ESCC patients and 79.6%, 20.4% in GCA patients. The distribution of genotype and allelotype in ESCC and GCA patients was not significantly different from that in healthy controls (P＞0.05). Compared to the A/A genotype, the combination of A/G and G/G genotypes did not show a significant effect on the risk of developing ESCC and GCA; the adjusted odds ratio was 0.92 (95%CI = 0.76-1.11) in ESCC and 0.95 (95% CI = 0.61-1.46)in GCA, respectively. When stratified for smoking status and family history of UGIC, the combination of A/G and G/G genotypes also did not show any significant influence on the risk of ESCC and GCA development compared to A/A genotypes.CONCLUSION: IL-10-G1082A polymorphism might not be used as a stratification marker to predicate the risk of ESCC and GCA development in North China.展开更多
The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3...The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 （GYb-YSZ） powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.展开更多
RNA-Seq, a high-throughput （HT） sequencing technique, has been used effectively in large-scale transcriptomic studies, and is particularly useful for improving gene structure information and mining of new genes. In ...RNA-Seq, a high-throughput （HT） sequencing technique, has been used effectively in large-scale transcriptomic studies, and is particularly useful for improving gene structure information and mining of new genes. In this study, RNA-Seq HT technology was employed to analyze the transcriptome of yak ovary. After lllurrlina-Solexa deep sequencing, 26826516 clean reads with a total of 4828772880 bp were obtained from the ovary library. Alignment analysis showed that 16992 yak genes mapped to the yak genome and 3734 of these genes were involved in alternative splicing. Gene structure refinement analysis showed that 7340 genes that were annotated in the yak genome could be extended at the 5＇ or 3＇ ends based on the alignments been the transcripts and the genome sequence. Novel transcript prediction analysis identified 6321 new transcripts with lengths ranging from 180 to 14884 bp, and 2267 of them were predicted to code proteins. BLAST analysis of the new transcripts showed that 1200-4933 mapped to the non-redundant （nr）, nucleotide （nt） and/or SwissProt sequence databases. Comparative statistical analysis of the new mapped transcripts showed that the majority of them were similar to genes in Bos taurus （41.4%）, Bos grunniens mutus （33.0%）, Ovis aries （6.3%）, Homo sapiens （2.8%）, Mus musculus （1.6%） and other species. Functional analy- sis showed that these expressed genes were involved in various Gene Ontology （GO） categories and Kyoto Encyclopedia of Genes and Genomes pathways. GO analysis of the new transcripts found that the largest proportion of them was associated with reproduction. The results of this study will provide a basis for describing the normal transcriptome map of yak ovary and for future studies on yak breeding performance. Moreover, the results confirmed that RNA-Seq HT technology is highly ad- vantageous in improving gene structure information and mining of new genes, as well as in providing valuable data to expand the yak genome information.展开更多
To elucidate the genetic characterization and molecular epidemiological features of Echovirus 19 （El9） isolates collected from an outbreak associated with hand, foot and mouth disease （HFMD） in Tai＇an city of Sha...To elucidate the genetic characterization and molecular epidemiological features of Echovirus 19 （El9） isolates collected from an outbreak associated with hand, foot and mouth disease （HFMD） in Tai＇an city of Shandong Province of China from July to September, 2003. Methods Thirty seven Echovirus 19 isolates were isolated from stool specimens and throat swabs collected during the outbreak, then major capsid （VP1） genomic sequence was determined, and phylogenetic tree was done based on the VP1 sequences among these 37 and other El9 viruses deposited in the Genbank. Also a representative strain named CHN-SD03-TN12 was selected for sequencing of 5′-untranslated regions （5′-UTR）. Results The identity rate was about 98.9%-100% among all these 37 El9 viruses. The genetic relationships between these 37 El9 isolates and other strains reported were also depicted. The identity rate was about 78.4%-78.9% compared with El9 reference strain Burke. The substitutions in the sequence of 5′-UTR resulted in changes in the conjectural properties of 5′-UTR of El9 viruses. Condusion The genetic features of El9 viruses isolated during the outbreak in Shandong Province in 2003 may be associated with a genetic and antigenic drift that changes the virulence of the Shandong isolates, but the molecular changes in Shandong El9 viruses contributing to their phenotype remain to be further illuminated. However, the sequences described in this paper substantiate the changes taken place in capsid VPI and 5′UTR regions. These substitutions may contribute to their tropism and virulence, and play a significant role in pathogenesis and clinical manifestations of the disease.展开更多
The surface deformation after fully mechanized back filling mining was analyzed.The surface deformation for different backfill materials was predicted by an equivalent mining height model and numerical simulations.The...The surface deformation after fully mechanized back filling mining was analyzed.The surface deformation for different backfill materials was predicted by an equivalent mining height model and numerical simulations.The results suggest that:(1) As the elastic modulus,E,of the backfill material increases the surface subsidence decreases.The rate of subsidence decrease drops after E is larger than 5 GPa;(2) Fully mechanized back fill mining technology can effectively control surface deformation.The resulting surface deformation is within the specification grade I,which means surface maintenance is not needed.A site survey showed that the equivalent mining height model is capable of predicting and analyzing surface deformation and that the model is conservative enough for engineering safety.Finally,the significance of establishing a complete error correction system based on error analysis and correction is discussed.展开更多
Objective:To evaluate the efficacy and safety of balloon occlusion of the abdominal aorta for the treatment of pernicious placenta previa with placenta accreta.Methods:The clinical data of 623 patients with pernicious...Objective:To evaluate the efficacy and safety of balloon occlusion of the abdominal aorta for the treatment of pernicious placenta previa with placenta accreta.Methods:The clinical data of 623 patients with pernicious placenta previa combined with placenta accrete,who were admitted to our hospital from January 2013 to January 2019 were retrospectively analyzed.All patients underwent abdominal aortic balloon occlusion combined with cesarean section,and 78 patients underwent sequential bilateral uterine artery embolization.We analyzed the operation time,intraoperative blood loss,blood transfusion volume,intraoperative and postoperative complications,fetal radiation exposure time and dose,and the Apgar score of the newborns.We also performed other evaluations to ascertain the efficacy and safety of abdominal aortic balloon occlusion treatment for dangerous placenta previa with placenta accrete.Results:Of the 623 patients,545 underwent only abdominal aortic balloon occlusion,and 78 underwent uterine artery embolization due to intraoperative or postoperative bleeding.The uterus was successfully preserved in all patients.Except for five cases of right lower extremity arterial thrombosis,the remaining patients did not have postoperative lower extremity arteriovenous thrombosis,renal insufficiency,late postpartum hemorrhage,ectopic embolism,spinal cord or peripheral nerve damage,pelvic infection,or other serious complications.The mean operative time was 65.3(±14.5)min.The mean intraoperative blood loss was620(±570)ml.Ninety-six patients(15.4%,96/623)were treated with blood transfusion,and the average amount of blood transfused was 750(±400)ml.The average number of hospitalization days was 6.8(±3.4)days,the average time of fetal ray exposure was 5.2(±1.6)s,and the average radiation dose was 4.1(±2.7)m Gy.The neonatal Apgar score,was 8.4(±0.6)points at 1 min,and 9.6(±0.4)points at 5 min.In the follow-up to May 31,2019,29 patients were lost to follow-up,96 were lactating,and 498 were menstruating.Except for the case展开更多
AIM: TO investigate the resistance rate of Helicobacter pylori(H pylori) to clarithromycin, metronidazole, amoxicillin and tetracycline to guide clinical practice, and to study the mechanism of Hpylori resistant to cl...AIM: TO investigate the resistance rate of Helicobacter pylori(H pylori) to clarithromycin, metronidazole, amoxicillin and tetracycline to guide clinical practice, and to study the mechanism of Hpylori resistant to clarithromycin. METHODS: Thirty Hpyloristrains were isolated from the mucosa of peptic ulcer, gastric tumor and chronic gastritis patients, then the minimal inhibitory concentration (MIC) to clarithromycin, metronidazole, amoxicillin and tetracycline was evaluated by E-test method. The sequence analysis of PCR fragments was conducted in 23S rRNA gene of H pylori resistant to clarithromycin to get the resistance mechanism of the bacteria. RESULTS: Among 30 Hpyloristrains, 7 cases were resistant to clarithromycin, 12 to metronidazole, 2 to tetracycline and no strain was found to be resistant to amoxicillin. The resistance rates were 23.3%, 40%, 6.7% and 0%, respectively. Three new mutation points were found to be related to the clarithromycin resistance in Hpyloriisolates, which were G2224A, C2245T and T2289C. CONCLUSION: In northeast China, H pylori shows high resistance to metronidazole, while sensitive to amoxicillin. The mechanism of resistance to clarithromycin may be related to the mutation of G2224A, C2245T and T2289C in the 23S rRNA gene.展开更多
Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones. We used factorial control experiment, under dew presence in the field, to explore ph...Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones. We used factorial control experiment, under dew presence in the field, to explore photosynthetic performance, water status and growth response of desert annual herbage. Bassia dasyphylla seedlings were grown in contrasting dew treatments （dew-absent and dew-present） and different watering regimes （normal and deficient）. The effects of dew on the water status and photosynthetic performance of Bassia dasyphylla grown in a desert area of the Hexi Corridor in Northwestern China, were evaluated. The results indicated the pres- ence of dew significantly increased relative water content （RWC） of shoots and total biomass of plants in both water regimes, and enhanced the diurnal shoot water potential and stomatal conductance in the early morning, as well as photosynthetic rate, which reached its maximum only in the water-stressed regime. The presence of dew increased aboveground growth of plants and photosynthate accumulation in leaves, but decreased the root-to-shoot ratio in both water regimes. Dew may have an important role in improving plant water status and ameliorating the adverse effects of plants exposed to prolonged drought.展开更多
The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid). Atmospheric H2O2 as an ancient signal mo...The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid). Atmospheric H2O2 as an ancient signal molecule not only plays the key role in inducing evolution of oxygenic photosynthesis, but also modulates many physiological events, such as stomatal movement, hypersensitive responses, programmed cell death and gene expressions. H2O2 levels in cells must sustain a fine equilibrium between production and scavenging. H2O2 enters cells from the apoplast or generated sources, and in turn is distributed in sub-cellular compartments. H2O2 can modulate the activities of many components in signaling, such as protein phosphatases, protein kinases, transcription factors (TFs), and calcium channels. Elevated cytosolic calcium concentrations will initiate further downstream responses, via the action of calcium-binding proteins. On the other hand, the research of H2O2 as a signal molecule is still in a comparatively juvenile stage, for example, little is known about how the cells sense H2O2, what the rate-limiting steps and most important cellular events are in cell signaling and what kind of genes is specific or necessary to H2O2 signaling. The answers to all the questions depend on the functional genomic and molecular genetics analysis.展开更多
In plants, root hairs are important organs for the up- take of nutrients and water from the rhizosphere and serve as sites of interaction with soil microorganisms [ 1]. A root hair grows as an extension of a single ep...In plants, root hairs are important organs for the up- take of nutrients and water from the rhizosphere and serve as sites of interaction with soil microorganisms [ 1]. A root hair grows as an extension of a single epidermal cell and is a simple system, making it an elegant model for studying higher plant cell differentiation and cell fate determination.展开更多
The quality control processes for herbal medicines have been problematic. Flavonoids are the major active components of Huangqin Tang(HQT, a traditional Chinese medicine formula). In this study, we used a combinative ...The quality control processes for herbal medicines have been problematic. Flavonoids are the major active components of Huangqin Tang(HQT, a traditional Chinese medicine formula). In this study, we used a combinative method approach consisting of chromatographic fingerprinting(high performance liquid chromatography; HPLC), quantitative methods and a pharmacodynamic evaluation model to analyze the flavonoids of HQT obtained from different sources. Ten batches of HQT were analyzed by the HPLC fingerprinting method and 26 common peaks were detected, of which 23 peaks corresponded with the chemical profile of HQT. In addition, 11 major compounds were identified by LC–MS analysis(liquid chromatography–tandem mass spectrometer; LC–MS^n) and quantified by the HPLC quantitative method approach. The studied10 batches of HQT were found to be homogeneous in their composition with a similarity between 0.990 and1.000. The distribution of the 11 identified compounds was found to be very similar among the batches. Only slight pharmacodynamic differences were detected between the different batches, confirming the homogeneity of HQT. The results of this study prove that the combination of chromatographic fingerprinting and quantitative analysis can be readily used for comprehensive quality control of herbal medicines.展开更多
Drought is a major abiotic stress that causes the yearly yield loss of maize, a crop cultured worldwide. Breeding drought-tolerant maize cultivars is a priority requirement of world agriculture. Clade A PP2C phosphata...Drought is a major abiotic stress that causes the yearly yield loss of maize, a crop cultured worldwide. Breeding drought-tolerant maize cultivars is a priority requirement of world agriculture. Clade A PP2C phosphatases （PP2C-A）, which are conserved in most plant species, play important roles in abscisic acid （ABA） signaling and plant drought response. However, natural variations of PP2C-A genes that are directly associated with drought tolerance remain to be elucidated. Here, we conducted a candidate gene association analysis of the ZmPP2C-A gene family in a maize panel consisting of 368 varieties collected worldwide, and identified a drought responsive gene ZmPP2C-AIO that is tightly associated with drought tolerance. We found that the degree of drought tolerance of maize cultivars negatively corre- lates with the expression levels of ZmPP2C-AIO. ZmPP2C-A10, like its Arabidopsis orthologs, interacts with ZmPYL ABA receptors and ZmSnRK2 kinases, suggesting that ZmPP2C-A10 is involved in mediating ABA signaling in maize. Transgenic studies in maize and Arabidopsis confirmed that ZmPP2C-A10 functions as a negative regulator of drought tolerance. Further, a causal natural variation, deletion allele-338, which bears a deletion of ERSE （endoplasmic reticulum stress response element） in the 51-UTR region of ZmPP2C-AIO, was detected. This deletion causes the loss of endoplasmic reticulum （ER） stress-induced expression of ZmPP2C-AIO, leading to increased plant drought tolerance. Our study provides direct evidence linking ER stress signaling with drought tolerance and genetic resources that can be used directly in breeding drought-tolerant maize cultivars.展开更多
In fall–winter, 2007–2013, visibility and light scattering coefficients（b sp） were measured along with PM_（2.5）mass concentrations and chemical compositions at a background site in the Pearl River Delta（PRD） r...In fall–winter, 2007–2013, visibility and light scattering coefficients（b sp） were measured along with PM_（2.5）mass concentrations and chemical compositions at a background site in the Pearl River Delta（PRD） region. The daily average visibility increased significantly（p 〈 0.01） at a rate of 1.1 km/year, yet its median stabilized at ~13 km. No haze days occurred when the 24-hr mean PM_（2.5）mass concentration was below 75 μg/m^3. By multiple linear regression on the chemical budget of particle scattering coefficient（b sp）, we obtained site-specific mass scattering efficiency（MSE） values of 6.5 ± 0.2, 2.6 ± 0.3, 2.4 ± 0.7 and 7.3 ± 1.2 m2/g,respectively, for organic matter（OM）, ammonium sulfate（AS）, ammonium nitrate（AN） and sea salt（SS）. The reconstructed light extinction coefficient（b ext） based on the Interagency Monitoring of Protected Visual Environments（IMPROVE） algorithm with our site-specific MSE revealed that OM, AS, AN, SS and light-absorbing carbon（LAC） on average contributed 45.9% ± 1.6%,25.6% ± 1.2%, 12.0% ± 0.7%, 11.2% ± 0.9% and 5.4% ± 0.3% to light extinction, respectively.Averaged b ext displayed a significant reduction rate of 14.1/Mm·year（p 〈 0.05）; this rate would be 82% higher if it were not counteracted by increasing relative humidity（RH） and hygroscopic growth factor（f（RH）） at rates of 2.5% and 0.16/year-1（p 〈 0.01）, respectively, during the fall–winter, 2007–2013. This growth of RH and f（RH） partly offsets the positive effects of lowered AS in improving visibility, and aggravated the negative effects of increasing AN to impair visibility.展开更多
基金This work is supported by the National Natural Science Youth Fund of China granted by No.61901452 and Innovative Project of ICT/CAS granted by No.20196110
文摘With the proliferation of the Internet of Things(IoT),various services are emerging with totally different features and requirements,which cannot be supported by the current fifth generation of mobile cellular networks(5G).The future sixth generation of mobile cellular networks(6G)is expected to have the capability to support new and unknown services with changing requirements.Hence,in addition to enhancing its capability by 10–100 times compared with 5G,6G should also be intelligent and open to adapt to the ever-changing services in the IoT,which requires a convergence of Communication,Computing and Caching(3C).Based on the analysis of the requirements of new services for 6G,this paper identifies key enabling technologies for an intelligent and open 6G network,all featured with 3C convergence.These technologies cover fundamental and emerging topics,including 3C-based spectrum management,radio channel construction,delay-aware transmission,wireless distributed computing,and network self-evolution.From the detailed analysis of these 3C-based technologies presented in this paper,we can see that although they are promising to enable an intelligent and open 6G,more efforts are needed to realize the expected 6G network.
基金This work was supported by the National Key Research and Development Program of China(2018YFA0800700 and 2018YFC1003200)and the National Natural Science Foundation of the P.R.of China(No.91857115,31925021,and 81921001).
文摘It is well known that an unhealthy lifestyle is a major risk factor for metabolic diseases,while in recent years,accumulating evidence has demonstrated that the gut microbiome and its metabolites also play a crucial role in the onset and development of many metabolic diseases,including obesity,type 2 diabetes,nonalcoholic fatty liver disease,cardiovascular disease and so on.Numerous microorganisms dwell in the gastrointestinal tract,which is a key interface for energy acquisition and can metabolize dietary nutrients into many bioactive substances,thus acting as a link between the gut microbiome and its host.The gut microbiome is shaped by host genetics,immune responses and dietary factors.The metabolic and immune potential of the gut microbiome determines its significance in host health and diseases.Therefore,targeting the gut microbiome and relevant metabolic pathways would be effective therapeutic treatments for many metabolic diseases in the near future.This review will summarize information about the role of the gut microbiome in organism metabolism and the relationship between gut microbiome-derived metabolites and the pathogenesis of many metabolic diseases.Furthermore,recent advances in improving metabolic diseases by regulating the gut microbiome will be discussed.
文摘AIM:To investigate maspin expression in tumorigenesis and progression of gastric cancer and to explore its relevant molecular mechanisms.METHODS:Formalin-fixed and paraffin-embedded tissues from normal mucosa (n=182), dysplasia (n=69), cancer (n=l13) of the stomach were studied for maspin expression by immunohistochemistry. Microvessel density (MVD) in gastric cancer was labeled using anti-CD34 antibody. Maspin expression was compared with clinical parameters and MVD of tumors. Caspase-3 expression was also detected in gastric carcinoma by immunohistochemistry. The relationship between Caspase-3 and maspin expression was concerned as well.RESULTS:The positive rates of maspin expression were 79.8% (145/182), 75.4%(52/69) and 50.4%(57/113) in normal mucosa, dysplasia and cancer of the stomach,respectively.Cancer less frequently expressed maspin than normal mucosa and dysplasia (P<0.05).Maspin expression showed a significantly negative association with invasive depth, metastasis, Lauren's and Nakamura's classification (P<0.05),but not with tumor size, Borrmann's classification,growth pattern or TNIVl staging (P>0.05). The positive rate of Caspase-3 was significantly lower in gastric cancer than in normal gastric mucosa (P<0.05,32.7% vs 50.4%). It was noteworthy that maspin expression was negatively correlated with MVD, but positively correlated with expression of Caspase-3 in gastric cancer (P<0.05).CONCLUSION:Down-regulated maspin expression is a late molecular event in gastric carcinogenesis. Reduced expression of maspin contributes to progression of gastric cancer probably by inhibiting cell adhesion, enhandng cell mobility,decreasing cell apoptosis and facilitating angiogenesis.Additionally altered expression of maspin underlies the molecular mechanism of differentiation of gastric cancer and supports the different histogenetic pathways of intestinal and diffuse gastric cancers. Maspin expression can be considered as an effective and objective marker to reveal biological behaviors of gastric cancer.
基金The National Key Technology Research and Development Program,No.2007BAC06B03National Basic Research Program of China,No.2005CB422000
文摘The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland for monitoring, protection and utilization. Wetland construction and distribution in the basin were analyzed based on multi-source data including field investigation data, CBERS remote sensing data and other thematic data provided by 3S technology. The results are （1） the total area of wetlands is 209,322.26 hm^2, accounting for 6.37% of the total land area of the basin. The wetlands are mainly dominated by natural wetland, with artificial wetland occupying only 1.09% of the wetland area; marsh wetland is the principal part of natural wetland, dominated by Kobresia littledalei swampy meadow which is distributed in the river source area and upstream of Chali, Damshung and Medro Gongkar counties. The ratio and type of wetlands in different counties differ significantly, which are widely distributed in Chali and Damshung counties （accounting for 62% of the total wetland area）. （2） The concentrated vertical distribution of wetlands is at an elevation of 3600-5100 m The wetlands are widely distributed throughout the Yarlung Zangbo River Valley from river source to river mouth into the Yarlung Zangbo River. Marsh wetland is dominant in the source area and upstream of the river, with the mosaic distribution of lakes, Kobresia litUedalei and Carex moorcroftii swampy meadow, shrubby swamp and river; as for the middle-down streams, the primary types are river wetland and flooded wetland. The distribution is in a mosaic pattern of river, Kobresia humilis and Carex moorcroftii swampy meadow, Phragmites australis and subordinate grass marsh, flooded wetland and artificial wetland.
基金supported by the Ministry of Science and Technology of China (2015CB553406)the National Natural Science Foundation of China (81230002, 81490531)the Ministry of Education (IRT1121, B08007)
文摘Pulmonary fibrosis, a progressive chronic disease with a high mortality rate, has limited treatment options. Currently, lung transplantation remains the only effective treatment. Here we report that a small RNA, HJT-sRNA-m7, from a Chinese herbal medicine Hong Jing Tian(HJT, RHODIOHAE CRENULATAE RADIX ET RHIZOMA, Rhodiola crenulata) can effectively reduce the expressions of fibrotic hallmark genes and proteins both in alveolar in vitro and in mouse lung tissues in vivo. We also discovered over one hundred oil-soluble chemicals from HJT decoctions, most of which are found in lipid extracts from other Chinese herbals decoctions, including Pu Gong Ying(PGY, TARAXACI HERBA, Taraxacum mongolicum), Chuan Xin Lian(CXL, changed to "ANDROGRAPHIS HERBA, Andrographis paniculata"), and Jin Yin Hua(JYH, lonicera japonica or Honeysuckle). We identified the active component in these decoctions as two forms of phosphocholines, PC(18:0/18:2) and PC(16:0/18:2). These PCs potentially could form liposomes with small RNAs to enter human alveolar and gastric cells. Our experimental results suggest an unprecendent lipid complex route through which botanic small RNA can enter human bodies.Our results provide an innovative treatment strategy for oral delivery of siRNAs as therapeutic medication.
文摘AIM: To investigate the polymorphisms of interleukin-18 (IL-18) gene promoters, and to disclose whether such polymorphisms are associated with susceptibility to chronic hepatitis B in Chinese Han population. METHODS: Using polymerase chain reaction with sequence specific primers (PCR-SSP) method, the single nucleotide polymorphisms (SNPs) of the promoter region of IL-18 gene at position -607 and -137 were detected in 231 patients with chronic hepatitis B and 300 normal controls. RESULTS: Allele C at position -607 in the promoter of IL-18 gene was detected in 48.7% of normal controls and 51.9% of patients, while allele A at position -607 was detected in 51.3% of normal controls and 48.1% of patients. The frequencies of -607CC, -607 CA and -607AA genotypes in normal controls were 22.0%, 53.3% and 24.7% respectively and in chronic hepatitis B patients were 26.8%, 50.2% and 23.0% respectively. Allele G at position -137 in the promoter of IL-18 gene was detected in 82.3% of normal controls and 88.5% of chronic hepatitis B patients, while allele C at position -137 was detected in 17.7% of normal controls and 11.5% of patients. The frequencies of -137GG, GC and CC genotype were 67.3%, 30.0% and 2.7% in normal controls respectively, while in chronic hepatitis B patients were 78.8%, 19.5% and 1.7% respectively. The frequency of-137GG genotype in chronic hepatitis B groups was significantly higher than that in normal controls (x2=8.55, P=0.003 <0.05), whereas the frequencies of -607C/-137C and -607A/-137C haplotypes in chronic hepatitis B groups were significantly lower than that in normal controls. The association between genotypes of IL-18 promoter region polymorphisms and HBV copies showed that the frequency of -607AA genotype in high HBV-DNA copies groups was lower than that in low HBV-DNA copies groups (x2=6.03, P=0.014 <0.05). CONCLUSION: The polymorphisms of the promoter region of IL-18 gene at position -607 and -137 are closely associated with susceptibility to chronic hepatitis B. The people with allele C at posit
文摘DNA methylation plays an important role in gene expression regulation during biological development and tissue differentiation in plants. This study adopted methylation-sensitive Amplified fragment length polymorphism （AFLP） to compare the levels of DNA cytosine methylation at CCGG sites in tassel, bracteal leaf, and ear leaf from maize inbred lines, 18 White and 18 Red, respectively, and also examined specific methylation patterns of the three tissues. Significant differences in cytosine methylation level among the three tissues and the same changing tendency in two inbred lines were detected. Both MSAP （methylation sensitive amplification polymorphism） ratio and full methylation level were the highest in bracteal leaf, and the lowest in tassel. Meanwhile, different methylation levels were observed in the same tissue from the inbred lines, 18 White and 18 Red. Full methylation of internal cytosine was the dominant type in the maize genome. The differential methylation patterns in the three tissues were observed. In addition, sequencing of nine differentially methylated fragments and the subsequent blast search revealed that the cytosine methylated 5 ＇ -CCGG-3 ＇ sequences were distributed in repeating sequences, in the coding and noncoding regions. Southern hybridization was used to verify the methylation polymorphism. These results clearly demonstrated the power of the MSAP technique for large-scale DNA methylation detection in the maize genome, and the complexity of DNA methylation change during plant growth and development. The different methylation levels may be related to specific gene expression in various tissues.
基金Supported by the National Natural Science Foundation of China,No. 30371591
文摘AIM: To investigate the possible association of G→A single nucleotide polymorphism (SNP) at the -1082 position of interleukin (IL)-10 promoter with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) in a population of a high incidence region of North China.METHODS: IL-10-G1082A promoter SNP was genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) in 355 cancer patients (203ESCC and 152 GCA) and 443 healthy controls.RESULTS: Smoking significantly increased the risk of ESCC and GCA development (the age and sex adjusted OR = 1.42and 2.64, 95%CI = 1.11-1.81 and 1.46-4.76, respectively).Similarly, family history of upper gastrointestinal cancer (UGIC) significantly increased the risk of developing ESCC and GCA (the age and sex adjusted OR = 1.44 and 3.10,95%CI = 1.18-1.75 and 1.94-4.97, respectively). The A/A, A/G and G/G genotype frequencies of IL-10-G1082A were 60.3%, 37.0% and 2.7% in healthy controls, 57.6%,39.9% and 2.5% in ESCC and 61.2%, 36.8% and 2.0% in GCA patients, respectively. The frequencies of A and G alleles were 78.8% and 21.2% in healthy controls, 77.6%and 22.4% in ESCC patients and 79.6%, 20.4% in GCA patients. The distribution of genotype and allelotype in ESCC and GCA patients was not significantly different from that in healthy controls (P＞0.05). Compared to the A/A genotype, the combination of A/G and G/G genotypes did not show a significant effect on the risk of developing ESCC and GCA; the adjusted odds ratio was 0.92 (95%CI = 0.76-1.11) in ESCC and 0.95 (95% CI = 0.61-1.46)in GCA, respectively. When stratified for smoking status and family history of UGIC, the combination of A/G and G/G genotypes also did not show any significant influence on the risk of ESCC and GCA development compared to A/A genotypes.CONCLUSION: IL-10-G1082A polymorphism might not be used as a stratification marker to predicate the risk of ESCC and GCA development in North China.
基金National Natural Science Foundation of China (50771009, 50731001)National Basic Research Program of China (2010CB631200)Research Fund for the Doctoral Program of Higher Education of China (20070006017)
文摘The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 （GYb-YSZ） powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.
基金supported by the National Science&Technology Pillar Program of China(2012BAD13B06)the Special Fund for Agroscientific Research in the Public Interest(201203009)
文摘RNA-Seq, a high-throughput （HT） sequencing technique, has been used effectively in large-scale transcriptomic studies, and is particularly useful for improving gene structure information and mining of new genes. In this study, RNA-Seq HT technology was employed to analyze the transcriptome of yak ovary. After lllurrlina-Solexa deep sequencing, 26826516 clean reads with a total of 4828772880 bp were obtained from the ovary library. Alignment analysis showed that 16992 yak genes mapped to the yak genome and 3734 of these genes were involved in alternative splicing. Gene structure refinement analysis showed that 7340 genes that were annotated in the yak genome could be extended at the 5＇ or 3＇ ends based on the alignments been the transcripts and the genome sequence. Novel transcript prediction analysis identified 6321 new transcripts with lengths ranging from 180 to 14884 bp, and 2267 of them were predicted to code proteins. BLAST analysis of the new transcripts showed that 1200-4933 mapped to the non-redundant （nr）, nucleotide （nt） and/or SwissProt sequence databases. Comparative statistical analysis of the new mapped transcripts showed that the majority of them were similar to genes in Bos taurus （41.4%）, Bos grunniens mutus （33.0%）, Ovis aries （6.3%）, Homo sapiens （2.8%）, Mus musculus （1.6%） and other species. Functional analy- sis showed that these expressed genes were involved in various Gene Ontology （GO） categories and Kyoto Encyclopedia of Genes and Genomes pathways. GO analysis of the new transcripts found that the largest proportion of them was associated with reproduction. The results of this study will provide a basis for describing the normal transcriptome map of yak ovary and for future studies on yak breeding performance. Moreover, the results confirmed that RNA-Seq HT technology is highly ad- vantageous in improving gene structure information and mining of new genes, as well as in providing valuable data to expand the yak genome information.
基金This work was supported by Chinese Center for Disease Control and Prevention and Ministry of Health,China.
文摘To elucidate the genetic characterization and molecular epidemiological features of Echovirus 19 （El9） isolates collected from an outbreak associated with hand, foot and mouth disease （HFMD） in Tai＇an city of Shandong Province of China from July to September, 2003. Methods Thirty seven Echovirus 19 isolates were isolated from stool specimens and throat swabs collected during the outbreak, then major capsid （VP1） genomic sequence was determined, and phylogenetic tree was done based on the VP1 sequences among these 37 and other El9 viruses deposited in the Genbank. Also a representative strain named CHN-SD03-TN12 was selected for sequencing of 5′-untranslated regions （5′-UTR）. Results The identity rate was about 98.9%-100% among all these 37 El9 viruses. The genetic relationships between these 37 El9 isolates and other strains reported were also depicted. The identity rate was about 78.4%-78.9% compared with El9 reference strain Burke. The substitutions in the sequence of 5′-UTR resulted in changes in the conjectural properties of 5′-UTR of El9 viruses. Condusion The genetic features of El9 viruses isolated during the outbreak in Shandong Province in 2003 may be associated with a genetic and antigenic drift that changes the virulence of the Shandong isolates, but the molecular changes in Shandong El9 viruses contributing to their phenotype remain to be further illuminated. However, the sequences described in this paper substantiate the changes taken place in capsid VPI and 5′UTR regions. These substitutions may contribute to their tropism and virulence, and play a significant role in pathogenesis and clinical manifestations of the disease.
基金provided by the National Natural Science Foundation of China (Nos. 51074165 and 50834004)
文摘The surface deformation after fully mechanized back filling mining was analyzed.The surface deformation for different backfill materials was predicted by an equivalent mining height model and numerical simulations.The results suggest that:(1) As the elastic modulus,E,of the backfill material increases the surface subsidence decreases.The rate of subsidence decrease drops after E is larger than 5 GPa;(2) Fully mechanized back fill mining technology can effectively control surface deformation.The resulting surface deformation is within the specification grade I,which means surface maintenance is not needed.A site survey showed that the equivalent mining height model is capable of predicting and analyzing surface deformation and that the model is conservative enough for engineering safety.Finally,the significance of establishing a complete error correction system based on error analysis and correction is discussed.
文摘Objective:To evaluate the efficacy and safety of balloon occlusion of the abdominal aorta for the treatment of pernicious placenta previa with placenta accreta.Methods:The clinical data of 623 patients with pernicious placenta previa combined with placenta accrete,who were admitted to our hospital from January 2013 to January 2019 were retrospectively analyzed.All patients underwent abdominal aortic balloon occlusion combined with cesarean section,and 78 patients underwent sequential bilateral uterine artery embolization.We analyzed the operation time,intraoperative blood loss,blood transfusion volume,intraoperative and postoperative complications,fetal radiation exposure time and dose,and the Apgar score of the newborns.We also performed other evaluations to ascertain the efficacy and safety of abdominal aortic balloon occlusion treatment for dangerous placenta previa with placenta accrete.Results:Of the 623 patients,545 underwent only abdominal aortic balloon occlusion,and 78 underwent uterine artery embolization due to intraoperative or postoperative bleeding.The uterus was successfully preserved in all patients.Except for five cases of right lower extremity arterial thrombosis,the remaining patients did not have postoperative lower extremity arteriovenous thrombosis,renal insufficiency,late postpartum hemorrhage,ectopic embolism,spinal cord or peripheral nerve damage,pelvic infection,or other serious complications.The mean operative time was 65.3(±14.5)min.The mean intraoperative blood loss was620(±570)ml.Ninety-six patients(15.4%,96/623)were treated with blood transfusion,and the average amount of blood transfused was 750(±400)ml.The average number of hospitalization days was 6.8(±3.4)days,the average time of fetal ray exposure was 5.2(±1.6)s,and the average radiation dose was 4.1(±2.7)m Gy.The neonatal Apgar score,was 8.4(±0.6)points at 1 min,and 9.6(±0.4)points at 5 min.In the follow-up to May 31,2019,29 patients were lost to follow-up,96 were lactating,and 498 were menstruating.Except for the case
文摘AIM: TO investigate the resistance rate of Helicobacter pylori(H pylori) to clarithromycin, metronidazole, amoxicillin and tetracycline to guide clinical practice, and to study the mechanism of Hpylori resistant to clarithromycin. METHODS: Thirty Hpyloristrains were isolated from the mucosa of peptic ulcer, gastric tumor and chronic gastritis patients, then the minimal inhibitory concentration (MIC) to clarithromycin, metronidazole, amoxicillin and tetracycline was evaluated by E-test method. The sequence analysis of PCR fragments was conducted in 23S rRNA gene of H pylori resistant to clarithromycin to get the resistance mechanism of the bacteria. RESULTS: Among 30 Hpyloristrains, 7 cases were resistant to clarithromycin, 12 to metronidazole, 2 to tetracycline and no strain was found to be resistant to amoxicillin. The resistance rates were 23.3%, 40%, 6.7% and 0%, respectively. Three new mutation points were found to be related to the clarithromycin resistance in Hpyloriisolates, which were G2224A, C2245T and T2289C. CONCLUSION: In northeast China, H pylori shows high resistance to metronidazole, while sensitive to amoxicillin. The mechanism of resistance to clarithromycin may be related to the mutation of G2224A, C2245T and T2289C in the 23S rRNA gene.
基金financially supported by the National Natural Sciences Foundation of China (30771767 and 40601016)
文摘Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones. We used factorial control experiment, under dew presence in the field, to explore photosynthetic performance, water status and growth response of desert annual herbage. Bassia dasyphylla seedlings were grown in contrasting dew treatments （dew-absent and dew-present） and different watering regimes （normal and deficient）. The effects of dew on the water status and photosynthetic performance of Bassia dasyphylla grown in a desert area of the Hexi Corridor in Northwestern China, were evaluated. The results indicated the pres- ence of dew significantly increased relative water content （RWC） of shoots and total biomass of plants in both water regimes, and enhanced the diurnal shoot water potential and stomatal conductance in the early morning, as well as photosynthetic rate, which reached its maximum only in the water-stressed regime. The presence of dew increased aboveground growth of plants and photosynthate accumulation in leaves, but decreased the root-to-shoot ratio in both water regimes. Dew may have an important role in improving plant water status and ameliorating the adverse effects of plants exposed to prolonged drought.
基金supported by the National Natural Science Foundation of China(Grant Nos.39870372,30370765&30440079)the National Key Basic Special Funds(Grant No.2003CB114305).
文摘The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid). Atmospheric H2O2 as an ancient signal molecule not only plays the key role in inducing evolution of oxygenic photosynthesis, but also modulates many physiological events, such as stomatal movement, hypersensitive responses, programmed cell death and gene expressions. H2O2 levels in cells must sustain a fine equilibrium between production and scavenging. H2O2 enters cells from the apoplast or generated sources, and in turn is distributed in sub-cellular compartments. H2O2 can modulate the activities of many components in signaling, such as protein phosphatases, protein kinases, transcription factors (TFs), and calcium channels. Elevated cytosolic calcium concentrations will initiate further downstream responses, via the action of calcium-binding proteins. On the other hand, the research of H2O2 as a signal molecule is still in a comparatively juvenile stage, for example, little is known about how the cells sense H2O2, what the rate-limiting steps and most important cellular events are in cell signaling and what kind of genes is specific or necessary to H2O2 signaling. The answers to all the questions depend on the functional genomic and molecular genetics analysis.
文摘In plants, root hairs are important organs for the up- take of nutrients and water from the rhizosphere and serve as sites of interaction with soil microorganisms [ 1]. A root hair grows as an extension of a single epidermal cell and is a simple system, making it an elegant model for studying higher plant cell differentiation and cell fate determination.
基金financially supported by the National Natural Science Foundation of China (Nos. 81273662 and 81473592)the Operational Expenses for Basic Research of China Academy of Chinese Medical Sciences (No. ZZ2014020)
文摘The quality control processes for herbal medicines have been problematic. Flavonoids are the major active components of Huangqin Tang(HQT, a traditional Chinese medicine formula). In this study, we used a combinative method approach consisting of chromatographic fingerprinting(high performance liquid chromatography; HPLC), quantitative methods and a pharmacodynamic evaluation model to analyze the flavonoids of HQT obtained from different sources. Ten batches of HQT were analyzed by the HPLC fingerprinting method and 26 common peaks were detected, of which 23 peaks corresponded with the chemical profile of HQT. In addition, 11 major compounds were identified by LC–MS analysis(liquid chromatography–tandem mass spectrometer; LC–MS^n) and quantified by the HPLC quantitative method approach. The studied10 batches of HQT were found to be homogeneous in their composition with a similarity between 0.990 and1.000. The distribution of the 11 identified compounds was found to be very similar among the batches. Only slight pharmacodynamic differences were detected between the different batches, confirming the homogeneity of HQT. The results of this study prove that the combination of chromatographic fingerprinting and quantitative analysis can be readily used for comprehensive quality control of herbal medicines.
文摘Drought is a major abiotic stress that causes the yearly yield loss of maize, a crop cultured worldwide. Breeding drought-tolerant maize cultivars is a priority requirement of world agriculture. Clade A PP2C phosphatases （PP2C-A）, which are conserved in most plant species, play important roles in abscisic acid （ABA） signaling and plant drought response. However, natural variations of PP2C-A genes that are directly associated with drought tolerance remain to be elucidated. Here, we conducted a candidate gene association analysis of the ZmPP2C-A gene family in a maize panel consisting of 368 varieties collected worldwide, and identified a drought responsive gene ZmPP2C-AIO that is tightly associated with drought tolerance. We found that the degree of drought tolerance of maize cultivars negatively corre- lates with the expression levels of ZmPP2C-AIO. ZmPP2C-A10, like its Arabidopsis orthologs, interacts with ZmPYL ABA receptors and ZmSnRK2 kinases, suggesting that ZmPP2C-A10 is involved in mediating ABA signaling in maize. Transgenic studies in maize and Arabidopsis confirmed that ZmPP2C-A10 functions as a negative regulator of drought tolerance. Further, a causal natural variation, deletion allele-338, which bears a deletion of ERSE （endoplasmic reticulum stress response element） in the 51-UTR region of ZmPP2C-AIO, was detected. This deletion causes the loss of endoplasmic reticulum （ER） stress-induced expression of ZmPP2C-AIO, leading to increased plant drought tolerance. Our study provides direct evidence linking ER stress signaling with drought tolerance and genetic resources that can be used directly in breeding drought-tolerant maize cultivars.
基金funded by Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB05010200)the Natural Science Foundation of China (Nos.41025012,41121063)the Bureau of Science,Technology and Information of Guangzhou (No.201300000130)
文摘In fall–winter, 2007–2013, visibility and light scattering coefficients（b sp） were measured along with PM_（2.5）mass concentrations and chemical compositions at a background site in the Pearl River Delta（PRD） region. The daily average visibility increased significantly（p 〈 0.01） at a rate of 1.1 km/year, yet its median stabilized at ~13 km. No haze days occurred when the 24-hr mean PM_（2.5）mass concentration was below 75 μg/m^3. By multiple linear regression on the chemical budget of particle scattering coefficient（b sp）, we obtained site-specific mass scattering efficiency（MSE） values of 6.5 ± 0.2, 2.6 ± 0.3, 2.4 ± 0.7 and 7.3 ± 1.2 m2/g,respectively, for organic matter（OM）, ammonium sulfate（AS）, ammonium nitrate（AN） and sea salt（SS）. The reconstructed light extinction coefficient（b ext） based on the Interagency Monitoring of Protected Visual Environments（IMPROVE） algorithm with our site-specific MSE revealed that OM, AS, AN, SS and light-absorbing carbon（LAC） on average contributed 45.9% ± 1.6%,25.6% ± 1.2%, 12.0% ± 0.7%, 11.2% ± 0.9% and 5.4% ± 0.3% to light extinction, respectively.Averaged b ext displayed a significant reduction rate of 14.1/Mm·year（p 〈 0.05）; this rate would be 82% higher if it were not counteracted by increasing relative humidity（RH） and hygroscopic growth factor（f（RH）） at rates of 2.5% and 0.16/year-1（p 〈 0.01）, respectively, during the fall–winter, 2007–2013. This growth of RH and f（RH） partly offsets the positive effects of lowered AS in improving visibility, and aggravated the negative effects of increasing AN to impair visibility.
