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11.
Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
12.
人肺腺癌细胞分化相关基因cDNAs的克隆 总被引:2,自引:0,他引:2
在用10-5 mol/L全反式维甲酸(RA)诱导人肺腺癌细胞系GLC-82分化的基础上,以M13噬菌粒pSPORT1为载体,应用定向克隆技术,分别构建了未经RA诱导和RA诱导1d及4d细胞的3个cDNA文库.以含重组子的诱导文库单链DNA为靶标(Target)同未诱导文库的cDNA驱除子(Driver)进行消减杂交,富集RA特异性单链DNA,将富集的单链DNA回复为双链后转化感受态菌,建立细胞诱导分化过程中活化表达基因的cDNA消减文库,得到124个cDNA消减克隆.经同源性分析和与文库总cDNA作Southern印迹杂交,进而与RA诱导前后细胞的RNA作Northern印迹杂交,筛选出2个(RA5,RA28)诱导后呈早期瞬时表达和1个(RA42)呈早期并持续表达的cDNA克隆,cDNA全长分别为1.8,1.5和0.7kb.序列测定及初步功能分析结果表明,RA5,RA28和RA42这3个首次报道的序列,可能是人肺腺癌细胞分化相关基因的cDNA克隆. 相似文献
13.
Gregory CA Amos Emma Gozzard Charlotte E Carter Andrew Mead Mike J Bowes Peter M Hawkey Lihong Zhang Andrew C Singer William H Gaze Elizabeth M H Wellington 《The ISME journal》2015,9(6):1467-1476
Multi-drug-resistant bacteria pose a significant threat to public health. The role of the environment in the overall rise in antibiotic-resistant infections and risk to humans is largely unknown. This study aimed to evaluate drivers of antibiotic-resistance levels across the River Thames catchment, model key biotic, spatial and chemical variables and produce predictive models for future risk assessment. Sediment samples from 13 sites across the River Thames basin were taken at four time points across 2011 and 2012. Samples were analysed for class 1 integron prevalence and enumeration of third-generation cephalosporin-resistant bacteria. Class 1 integron prevalence was validated as a molecular marker of antibiotic resistance; levels of resistance showed significant geospatial and temporal variation. The main explanatory variables of resistance levels at each sample site were the number, proximity, size and type of surrounding wastewater-treatment plants. Model 1 revealed treatment plants accounted for 49.5% of the variance in resistance levels. Other contributing factors were extent of different surrounding land cover types (for example, Neutral Grassland), temporal patterns and prior rainfall; when modelling all variables the resulting model (Model 2) could explain 82.9% of variations in resistance levels in the whole catchment. Chemical analyses correlated with key indicators of treatment plant effluent and a model (Model 3) was generated based on water quality parameters (contaminant and macro- and micro-nutrient levels). Model 2 was beta tested on independent sites and explained over 78% of the variation in integron prevalence showing a significant predictive ability. We believe all models in this study are highly useful tools for informing and prioritising mitigation strategies to reduce the environmental resistome. 相似文献
14.
Bacon L Eagle RA Meyer M Easom N Young NT Trowsdale J 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(2):1078-1084
We characterized two novel members of the RAET1/ULBP gene cluster, RAET1E and RAET1G. The encoded proteins were similar to the ULBP in their class I-like alpha1 and alpha2 domains, but differed in that, instead of being GPI-anchored, their sequences were type 1 membrane-spanning molecules. Both proteins were capable of being expressed at the cell surface. Both proteins bound the activating receptor NKG2D, and RAET1G bound the human CMV protein UL16. The expression of diverse NKG2D-binding molecules in different tissues and with different properties is consistent with multiple modes of infection- or stress-induced activation. 相似文献
15.
JOSEP PIÑOL XAVIER ESPADALER NÚRIA CAÑELLAS JORDI MARTÍNEZ‐VILALTA JOSÉ A. BARRIENTOS DANIEL SOL 《Ecological Entomology》2010,35(3):367-376
1. Predation‐exclusion experiments have highlighted that top‐down control is pervasive in terrestrial communities, but most of these experiments are simplistic in that they only excluded a single group of predators and the effect of removal was evaluated on a few species from the community. The main goal of our study was to experimentally establish the relative effects of ants and birds on the same arthropod assemblage of canopy trees. 2. We conducted 1‐year long manipulative experiments in an organic citrus grove intended to quantify the independent effects of bird and ant predators on the abundance of arthropods. Birds were excluded with plastic nets whereas ants were excluded with sticky barriers on the trunks. The sticky barrier also excluded other ground dwelling insects, like the European earwig Forficula auricularia L. 3. Both the exclusion of ants and birds affected the arthropod community of the citrus canopies, but the exclusion of ants was far more important than the exclusion of birds. Indeed, almost all groups of arthropods had higher abundance in ant‐excluded than in control trees, whereas only dermapterans were more abundant in bird‐excluded than in control trees. A more detailed analysis conducted on spiders also showed that the effect of ant exclusion was limited to a few families rather than being widespread over the entire diverse spectrum of spiders. 4. Our results suggest that the relative importance of vertebrate and invertebrate predators in regulating arthropod populations largely depends on the nature of the predator–prey system. 相似文献
16.
Genetic tailoring of N-linked oligosaccharides: the role of glucose residues in glycoprotein processing of Saccharomyces cerevisiae in vivo 总被引:1,自引:0,他引:1
In higher eukaryotes a quality control system monitoring the folding state
of glycoproteins is located in the ER and is composed of the proteins
calnexin, calreticulin, glucosidase II, and UDP-glucose: glycoprotein
glucosyltransferase. It is believed that the innermost glucose residue of
the N- linked oligosaccharide of a glycoprotein serves as a tag in this
control system and therefore performs an important function in the protein
folding pathway. To address this function, we constructed Saccharomyces
cerevisiae strains which contain nonglucosylated (G0), monoglucosylated
(G1), or diglucosylated (G2) glycoproteins in the ER and used these strains
to study the role of glucose residues in the ER processing of
glycoproteins. These alterations of the oligosaccharide structure did not
result in a growth phenotype, but the induction of the unfolded protein
response upon treatment with DTT was much higher in G0 and G2 strains as
compared to wild-type and G1 strains. Our results provide in vivo evidence
that the G1 oligosaccharide is an active oligosaccharide structure in the
ER glycoprotein processing pathway of S.cerevisiae. Furthermore, by
analyzing N- linked oligosaccharides of the constructed strains we can
directly show that no general glycoprotein glucosyltransferase exists in S.
cerevisiae.
相似文献
17.
Diurnal changes in the fraction of 3-hydroxy-3-methylglutaryl-CoA reductase in the active form in rat liver microsomal fractions. 总被引:4,自引:3,他引:4 下载免费PDF全文
'Initial' and 'total' activities of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase) were measured in cold-clamped samples of liver from rats at 2h intervals throughout the 24h light/dark cycle. Initial activities were obtained in microsomes (microsomal fractions) isolated and assayed in the presence of 100mM-KF, whereas 'total' activities were measured in microsomes prepared from the same homogenates but washed free of KF and incubated with exogenous partially purified rat liver protein phosphatase. The initial/total-activity ratio for HMG-CoA reductase underwent a diurnal cycle, which had a nadir 4h into the light phase (when initial activity was 28% of total activity) and a peak 12h later, i.e. 4h into the dark phase (when initial activity was 80% of total activity). These low and high points of the cycle were separated by gradual steady changes in the ratio. The characteristics of this diurnal cycle were different from those of the cycle observed for total activity, which had a plateau of high activity between 2 and 10h into the dark cycle preceded and succeeded by a very rapid increase and decrease, respectively, in the total activity of HMG-CoA reductase. The combination of the two cycles resulted in the dampening of the resultant cycle for the initial or effective activity of HMG-CoA reductase, such that the changes in initial activity around the beginning and and end of the dark phase were more gradual than would otherwise have been the case if the initial/total-activity ratio for HMG-CoA reductase were constant throughout the diurnal cycle. The physiological implications of the observed diurnal variation in the fraction of hepatic HMG-CoA reductase in the active form are discussed. 相似文献
18.
Donelan MJ Morfini G Julyan R Sommers S Hays L Kajio H Briaud I Easom RA Molkentin JD Brady ST Rhodes CJ 《The Journal of biological chemistry》2002,277(27):24232-24242
The specific biochemical steps required for glucose-regulated insulin exocytosis from beta-cells are not well defined. Elevation of glucose leads to increases in cytosolic [Ca2+]i and biphasic release of insulin from both a readily releasable and a storage pool of beta-granules. The effect of elevated [Ca2+]i on phosphorylation of isolated beta-granule membrane proteins was evaluated, and the phosphorylation of four proteins was found to be altered by [Ca2+]i. One (a 18/20-kDa doublet) was a Ca2+-dependent increase in phosphorylation, and, surprisingly, three others (138, 42, and 36 kDa) were Ca2+-dependent dephosphorylations. The 138-kDa beta-granule phosphoprotein was found to be kinesin heavy chain (KHC). At low levels of [Ca2+]i KHC was phosphorylated by casein kinase 2, but KHC was rapidly dephosphorylated by protein phosphatase 2B beta (PP2Bbeta) as [Ca2+]i increased. Inhibitors of PP2B specifically reduced the second, microtubule-dependent, phase of insulin secretion, suggesting that dephosphorylation of KHC was required for transport of beta-granules from the storage pool to replenish the readily releasable pool of beta-granules. This is distinct from synaptic vesicle exocytosis, because neurotransmitter release from synaptosomes did not require a Ca2+-dependent KHC dephosphorylation. These results suggest a novel mechanism for regulating KHC function and beta-granule transport in beta-cells that is mediated by casein kinase 2 and PP2B. They also implicate a novel regulatory role for PP2B/calcineurin in the control of insulin secretion downstream of a rise in [Ca2+]i. 相似文献
19.
目的:早期液体复苏对感染性休克患者血流动力学的影响。方法:选取2012年2月-2013年2月我院ICU收治的26例感染性休克患者作为研究对象,随机分为对照组和试验组,各13例。两组患者均采用PICCO监测,并根据早期复苏目标导向(Earlygoaldirectedtherapy,EGDT)进行早期液体复苏治疗。对照组和试验组复苏液分别为林格液和6%羟乙基淀粉130/0.4氯化钠溶液。分别于复苏开始时(Oh)、8h和24h收集患者的血流动力学参数。结果:两组患者CO及PAWP水平均随着时间的延长下降,而CI、CVP及SVR水平均随着时间的增加上升。除对照组CI外,与开始复苏(oh)相比较试验组和对照组的C0、CI、CVP、SVR及PAWP与开始复苏(O小时)相比较均有显著差异(P值均〈0.05)。经重复测量资料的.方差分析进行比较发现,与对照组相比较,试验组CVP和SVR上升水平及PAWP下降水平明显,差异具有统计学意义(P值均〈0.05)。结论:感染性休克患者使用6%羟乙基淀粉130/0.4氯化钠溶液进行复苏,能更好的改善患者的血流动力学指标。 相似文献
20.
Molecular phylogeny and divergence times of drosophilid species 总被引:17,自引:15,他引:17
The phylogenetic relationships and divergence times of 39 drosophilid
species were studied by using the coding region of the Adh gene. Four
genera--Scaptodrosophila, Zaprionus, Drosophila, and Scaptomyza (from
Hawaii)--and three Drosophila subgenera--Drosophila, Engiscaptomyza, and
Sophophora--were included. After conducting statistical analyses of the
nucleotide sequences of the Adh, Adhr (Adh-related gene), and nuclear rRNA
genes and a 905-bp segment of mitochondrial DNA, we used Scaptodrosophila
as the outgroup. The phylogenetic tree obtained showed that the first major
division of drosophilid species occurs between subgenus Sophophora (genus
Drosophila) and the group including subgenera Drosophila and Engiscaptomyza
plus the genera Zaprionus and Scaptomyza. Subgenus Sophophora is then
divided into D. willistoni and the clade of D. obscura and D. melanogaster
species groups. In the other major drosophilid group, Zaprionus first
separates from the other species, and then D. immigrans leaves the
remaining group of species. This remaining group then splits into the D.
repleta group and the Hawaiian drosophilid cluster (Hawaiian Drosophila,
Engiscaptomyza, and Scaptomyza). Engiscaptomyza and Scaptomyza are tightly
clustered. Each of the D. repleta, D. obscura, and D. melanogaster groups
is monophyletic. The splitting of subgenera Drosophila and Sophophora
apparently occurred about 40 Mya, whereas the D. repleta group and the
Hawaiian drosophilid cluster separated about 32 Mya. By contrast, the
splitting of Engiscaptomyza and Scaptomyza occurred only about 11 Mya,
suggesting that Scaptomyza experienced a rapid morphological evolution. The
D. obscura and D. melanogaster groups apparently diverged about 25 Mya.
Many of the D. repleta group species studied here have two functional Adh
genes (Adh-1 and Adh-2), and these duplicated genes can be explained by two
duplication events.
相似文献