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1.
Pasquier CM; Promponas VI; Varvayannis NJ; Hamodrakas SJ 《Bioinformatics (Oxford, England)》1998,14(8):749-750
Summary : FT is a tool written in C++, which implements the Fourier
analysis method to locate periodicities in aminoacid or DNA sequences. It
is provided for free public use on a WWW server with a Java interface.
Availability : The server address is http://o2.db. uoa.gr/FT Contact :
shamodr@atlas.uoa.gr
相似文献
2.
In a variety of tumour systems, individuals carrying progressively growing neoplasms have lymphoid cells with a specific cytotoxic effect on cultured tumour cells from the same individual1–4. Since the sera of tumour-bearing individuals have been shown to prevent tumour cell destruction by immune lymphocytes in vitro2,5–8 and since this serum blocking activity appears early in primary and transplant tumour development5,7, it has been suggested that the appearance of this serum blocking activity might be responsible for the progressive growth of tumours in individuals having cytotoxic lymphocytes. Counteraction of this blocking activity would thus be of primary importance in facilitating the function of an already existing or bolstered cell-mediated immunity. The serum blocking activity might be inhibited in various ways, by preventing the formation of blocking antibody or by interfering with its action (“unblocking”), as demonstrated in Moloney sarcoma regressor sera9. This type of serum also has a therapeutic effect on Moloney sarcomas in vivo10,11, which has been tentatively attributed to its unblocking activity8,9 or, possibly, to a complement-dependent cytotoxicity10. Tumour growth in the Moloney sarcoma system, however, might be due in part to continuous recruitment of neoplastic cells by virus-induced transformation and so the therapeutic effect could be due to a virus-neutralizing serum activity9,10. 相似文献
3.
On the mechanism of ATP-induced shape changes in the human erythrocyte membranes: the role of ATP 下载免费PDF全文
In the preceding paper (Sheetz, M. and S.J. Singer. 1977. J Cell Biol. 73:638-646) it was shown that erythrocyte ghosts undergo pronounced shape changes in the presence of mg-ATP. The biochemical effects of the action of ATP are herein examined. The biochemical effects of the action of ATP are herein examined. Phosphorylation by ATP of spectrin component 2 of the erythrocyte membrane is known to occur. We have shown that it is only membrane protein that is significantly phosphorylated under the conditions where the shape changes are produced. The extent of this phosphorylation rises with increasing ATP concentration, reaching nearly 1 mol phosphoryle group per mole of component 2 at 8mM ATP. Most of this phosphorylation appears to occur at a single site on the protein molecule, according to cyanogen bromide peptide cleavage experiments. The degree of phosphorylation of component 2 is apparently also regulated by a membrane-bound protein phosphatase. This activity can be demonstrated in erythrocyte ghosts prepared from intact cells prelabeled with [(32)P]phosphate. In addition to the phosphorylation of component 2, some phosphorylation of lipids, mainly of phosphatidylinositol, is also known to occur. The ghost shape changes are, however, shown to be correlated with the degree of phosphorylation of component 2. In such experiment, the incorporation of exogenous phosphatases into ghosts reversed the shape changes produced by ATP, or by the membrane-intercalating drug chlorpromazine. The results obtained in this and the preceding paper are consistent with the proposal that the erythrocyte membrane possesses kinase and phosphates activities which produce phosphorylation and dephosphorylation of a specific site on spectrin component 2 molecules; the steady-state level of this phosphorylation regulates the structural state of the spectrin complex on the cytoplasmic surface of the membrane, which in turn exerts an important control on the shape of the cell. 相似文献
4.
Gold salts and phenylbutazone selectively inhibit the synthesis of PGF2α and PGE2 respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE2 and PGF2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action
and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function. 相似文献
5.
JF Yuan SJ Zhang O Jafer RA Furlong OE Chausiaux CA Sargent GH Zhang NA Affara 《BMC microbiology》2009,9(1):246
Background
Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult. 相似文献6.
Background
Fetal movement counting is a method used by the mother to quantify her baby''s movements, and may prevent adverse pregnancy outcome by a timely evaluation of fetal health when the woman reports decreased fetal movements. We aimed to assess effects of fetal movement counting on identification of fetal pathology and pregnancy outcome.Methodology
In a multicentre, randomized, controlled trial, 1076 pregnant women with singleton pregnancies from an unselected population were assigned to either perform fetal movement counting from gestational week 28, or to receive standard antenatal care not including fetal movement counting (controls). Women were recruited from nine Norwegian hospitals during September 2007 through November 2009. Main outcome was a compound measure of fetal pathology and adverse pregnancy outcomes. Analysis was performed by intention-to-treat.Principal Findings
The frequency of the main outcome was equal in the groups; 63 of 433 (11.6%) in the intervention group, versus 53 of 532 (10.7%) in the control group [RR: 1.1 95% CI 0.7–1.5)]. The growth-restricted fetuses were more often identified prior to birth in the intervention group than in the control group; 20 of 23 fetuses (87.0%) versus 12 of 20 fetuses (60.0%), respectively, [RR: 1.5 (95% CI 1.0–2.1)]. In the intervention group two babies (0.4%) had Apgar scores <4 at 1 minute, versus 12 (2.3%) in the control group [RR: 0.2 (95% CI 0.04–0.7)]. The frequency of consultations for decreased fetal movement was 71 (13.1%) and 57 (10.7%) in the intervention and control groups, respectively [RR: 1.2 (95% CI 0.9–1.7)]. The frequency of interventions was similar in the groups.Conclusions
Maternal ability to detect clinically important changes in fetal activity seemed to be improved by fetal movement counting; there was an increased identification of fetal growth restriction and improved perinatal outcome, without inducing more consultations or obstetric interventions.Trial Registration
ClinicalTrials.gov NCT00513942相似文献7.
8.
Ie-Bin Lian Yi-Hsien Lin Ying-Chao Lin Hsin-Chou Yang Chee-Jang Chang Cathy SJ Fann 《BMC bioinformatics》2008,9(1):246
Background
Association testing is a powerful tool for identifying disease susceptibility genes underlying complex diseases. Technological advances have yielded a dramatic increase in the density of available genetic markers, necessitating an increase in the number of association tests required for the analysis of disease susceptibility genes. As such, multiple-tests corrections have become a critical issue. However the conventional statistical corrections on locus-specific multiple tests usually result in lower power as the number of markers increases. Alternatively, we propose here the application of the longest significant run (LSR) method to estimate a region-specific p-value to provide an index for the most likely candidate region. 相似文献9.
Stray JE Crisona NJ Belotserkovskii BP Lindsley JE Cozzarelli NR 《The Journal of biological chemistry》2005,280(41):34723-34734
Smc2/4 forms the core of the Saccharomyces cerevisiae condensin, which promotes metaphase chromosome compaction. To understand how condensin manipulates DNA, we used two in vitro assays to study the role of SMC (structural maintenance of chromosome) proteins and ATP in reconfiguring the path of DNA. The first assay evaluated the topology of knots formed in the presence of topoisomerase II. Unexpectedly, both wild-type Smc2/4 and an ATPase mutant promoted (+) chiral knotting of nicked plasmids, revealing that ATP hydrolysis and the non-SMC condensins are not required to compact DNA chirally. The second assay measured Smc2/4-dependent changes in linking number (Lk). Smc2/4 did not induce (+) supercoiling, but instead induced broadening of topoisomer distributions in a cooperative manner without altering Lk(0). To explain chiral knotting in substrates devoid of chiral supercoiling, we propose that Smc2/4 directs chiral DNA compaction by constraining the duplex to retrace its own path. In this highly cooperative process, both (+) and (-) loops are sequestered (about one per kb), leaving net writhe and twist unchanged while broadening Lk. We have developed a quantitative theory to account for these results. Additionally, we have shown at higher molar stoichiometries that Smc2/4 prevents relaxation by topoisomerase I and nick closure by DNA ligase, indicating that Smc2/4 can saturate DNA. By electron microscopy of Smc2/4-DNA complexes, we observed primarily two protein-laden bound species: long flexible filaments and uniform rings or "doughnuts." Close packing of Smc2/4 on DNA explains the substrate protection we observed. Our results support the hypothesis that SMC proteins bind multiple DNA duplexes. 相似文献
10.
Here we report the effect of a heteroaryldihydropyrimidine (HAP) antiviral compound, BAY 41-4109, on Hepatitis B virus (HBV) capsid assembly and on preformed HBV capsids. The HBV capsid is an icosahedral complex of 120 capsid protein dimers. BAY41-4109 inhibits virus production in vivo by a mechanism that targets the viral capsid. We found that BAY 41-4109 was able to both accelerate and misdirect capsid assembly in vitro. As little as one HAP molecule for every five HBV dimers was sufficient to induce formation of non-capsid polymers. Unlike the related molecule HAP-1 (Stray et al., Proc. Natl. Acad. Sci. USA 102:8138-43, 2005), no stable assembly intermediates were observed in assembly reactions with BAY 41-4109, indicating that accelerated assembly by BAY 41-4109 was still kinetically regulated by the nucleation rate. Preformed capsids were stabilized by BAY 41-4109, up to a ratio of one inhibitor molecule per two dimers. However, at BAY 41-4109:dimer ratios of 1:1 and greater, capsids were destabilized to yield very large non-capsid polymers. These data suggest the existence of two functionally distinguishable classes of drug-binding sites on HBV capsids. Occupation of the first class of site stabilizes capsid, while binding at the second class requires or induces structural changes that cannot be tolerated without destabilizing the capsid. Our data suggest that HAP compounds may inhibit virus replication by inducing assembly inappropriately and, when in excess, by misdirecting assembly decreasing the stability of normal capsids. 相似文献