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1.
Characterization of endogenous and recombinant proviral elements of a highly tumorigenic AKR cell line 总被引:1,自引:0,他引:1 下载免费PDF全文
C Lamont P Culp R L Talbott T R Phillips R J Trauger W N Frankel M C Wilson J M Coffin J H Elder 《Journal of virology》1991,65(9):4619-4628
As an approach to evaluating the contribution of classes of endogenous viral sequences to leukemogenesis, a genomic library was prepared from the highly tumorigenic AKR SL12.3 cell line and screened for env-containing proviruses. An extensive battery of virus-derived probes and specific oligonucleotide probes were used to segregate 83 positive clones into related groups. The nonecotropic endogenous retroviruses were identified as members of the polytropic, modified polytropic, or xenotropic groups. At least three unique xenotropic proviruses were detected that differed from the published xenotropic sequence within a variable region of the 5' portion of env. Changes among the xenotropic proviruses included relative insertions and/or deletions that maintain an open reading frame and hence the potential to encode viable envelope gene products. Several recombinant viruses were also detected. Recombination was not random and primarily involved the formation of mink cell focus-inducing class I retroviruses via recombination between polytropic elements and ecotropic virus. One other recombinant was detected which contained ecotropic virus sequences in the 5' region encoding p15 of an otherwise xenotropic provirus. An interesting observation was the finding that certain clones contained more than one provirus within the average 20-kb cloned insert. This would not be expected if integration were totally random. The de novo recombinant proviruses identified here provide a series of potential candidates to be evaluated for their contribution to the tumorigencity of the SL12.3 cell line. 相似文献
2.
R J Trauger R Talbott S H Wilson R L Karpel J H Elder 《The Journal of biological chemistry》1990,265(7):3674-3678
We have used an antisynthetic peptide antiserum to a murine recombinant virus gp70 to probe normal mouse tissues for immunologically related proteins. In addition to cognate gp70s, this antiserum reacts with the heterogeneous nuclear ribonucleoparticle protein A1 by virtue of a 5-amino acid epitope, PRNQG. Further structural similarity is evident both 5' and 3' of this epitope. Since the function of the heterogeneous nuclear ribonucleoprotein particles in the cell is to aid in the stabilization and processing of newly synthesized RNA, we have investigated whether this retroviral sequence exhibits any nucleic acid-binding properties by the same criteria established for the identification of heterogeneous nuclear ribonucleoprotein particles. Analysis of the peptide in a poly(eA) binding assay shows this retroviral sequence to bind with high affinity to single-stranded nucleic acid. This binding occurs in a salt-sensitive manner characteristic of single-stranded nucleic acid-binding proteins. Flanking peptides not containing this sequence generated from either the A1 or gp70 show no ability to bind single-stranded nucleic acids by this assay. 相似文献
3.
Hao Xiang Kristen J. Mertz Vincent C. Arena Luann L. Brink Xiaohui Xu Yongyi Bi Evelyn O. Talbott 《PloS one》2013,8(4)
Background and Objective
High concentrations of air pollutants have been linked to increased incidence of stroke in North America and Europe but not yet assessed in mainland China. The aim of this study is to evaluate the association between stroke hospitalization and short-term elevation of air pollutants in Wuhan, China.Methods
Daily mean NO2, SO2 and PM10 levels, temperature and humidity were obtained from 2006 through 2008. Data on stroke hospitalizations (ICD 10: I60–I69) at four hospitals in Wuhan were obtained for the same period. A time-stratified case-crossover design was performed by season (April-September and October-March) to assess effects of pollutants on stroke hospital admissions.Results
Pollution levels were higher in October-March with averages of 136.1 µg/m3 for PM10, 63.6 µg/m3 for NO2 and 71.0 µg/m3 for SO2 than in April-September when averages were 102.0 µg/m3, 41.7 µg/m3 and 41.7 µg/m3, respectively (p<.001). During the cold season, every 10 µg/m3 increase in NO2 was associated with a 2.9% (95%C.I. 1.2%–4.6%) increase in stroke admissions on the same day. Every 10 ug/m3 increase in PM10 daily concentration was significantly associated with an approximate 1% (95% C.I. 0.1%–1.4%) increase in stroke hospitalization. A two-pollutant model indicated that NO2 was associated with stroke admissions when controlling for PM10. During the warm season, no significant associations were noted for any of the pollutants.Conclusions
Exposure to NO2 is significantly associated with stroke hospitalizations during the cold season in Wuhan, China when pollution levels are 50% greater than in the warm season. Larger and multi-center studies in Chinese cities are warranted to validate our findings. 相似文献4.
Fouling by biofilms significantly increases frictional drag on ships' hulls. A device, the friction disk machine, designed to measure torque on rotating disks, was used to examine differences among experimental fouling-release coatings in the drag penalty due to accumulated biofilms. Penalties were measured as the percentage change in the frictional resistance coefficient Cf. Drag penalties due to microfouling ranged from 9% to 29%, comparable to previously reported values. An antifouling control coating showed a smaller drag penalty than the fouling-release coatings. There were also significant differences among the fouling-release coatings in drag due to biofilm formation. These results indicate that the friction disk machine may serve as a valuable tool for investigating the effects of experimental coatings, both antifouling and fouling-release, on microfouling and associated drag penalties. 相似文献
5.
Solute content of stomata from intact onion cotyledons grownunder either greenhouse or growth chamber conditions was followedover the course of a daily light cycle to determine patternsof osmoregulation. Initial opening of stomata was well correlatedwith guard cell potassium accumulation under both growth conditions.Subsequently, however, there was a consistent decrease in guardcell potassium content despite constant or increasing aperture.Although a secondary increase in potassium was sometimes observedduring the second half of the light cycle, guard cell potassiumcontent was poorly correlated with aperture. Sucrose levelsin guard cells increased 60% during the period of decliningpotassium content, suggesting its use as an alternate osmoticum.Guard cells are postulated to use multiple pathways for theproduction of osmotica over the course of a complete daily cycleof stomatal movements. (Received December 5, 1995; Accepted April 9, 1996) 相似文献
6.
Helena J Bailes Wayne L Davies Ann EO Trezise Shaun P Collin 《BMC evolutionary biology》2007,7(1):200
Background
One of the greatest challenges facing the early land vertebrates was the need to effectively interpret a terrestrial environment. Interpretation was based on ocular adaptations evolved for an aquatic environment millions of years earlier. The Australian lungfish Neoceratodus forsteri is thought to be the closest living relative to the first terrestrial vertebrate, and yet nothing is known about the visual pigments present in lungfish or the early tetrapods. 相似文献7.
8.
EO Ogueji CD Nwani SC Iheanacho CE Mbah CO Okeke A Yaji 《African Journal of Aquatic Science》2018,43(3):293-303
Indiscriminate discharge of pharmaceutical waste into the aquatic ecosystem may pose serious health challenges to aquatic biota. The effect of acute exposure to ibuprofen was evaluated using changes in behaviour and haematological parameters under static bio-assay method in Clarias gariepinus. Test specimens were exposed to acute concentrations of ibuprofen (0.28, 0.33, 0.38, 0.43 and 0.48 mg l?1) for 24, 48, 72 and 96 h durations respectively. Behavioural and phenotypic changes were observed in surviving fish. There were significant (p < 0.05) concentration and duration-dependent increases in erythrocyte (RBC), haemoglobin (Hb), pack cell volume (PCV) and leukocytes (WBC) in treated fish compared to the control. Insignificant decreases (p > 0.05) in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were observed in treated fish compared to the control. Ibuprofen elicited dose and duration- dependent decrease in neutrophil counts with the decreases being significant (p < 0.05) in the higher doses of 0.43 and 0.48 mg l?1. Ibuprofen did not elicit any significant changes in monocytes, basophils and eosinophils. Changes observed in this study showed that ibuprofen negatively affected the health of the fish and we recommend that discharge of ibuprofen into the aquatic environment should be monitored and controlled. 相似文献
9.
Susan E. Bentz Bruce J. Parliman Helen-Jean Talbott William L. Ackerman 《Plant Cell, Tissue and Organ Culture》1988,14(2):111-120
A micropropagation system was developed to facilitate the release and subsequent testing of unique pink- or white-flowered selections of Yucca glauca. Shoot tip explants from mature plants were cultured on Murashige and Skoog medium supplemented with factorial combinations of -naphthaleneacetic acid (NAA) (0.0 to 3.2 M) and 6-benzylaminopurine (BA) (0.0 to 45 M). Shoots were found to proliferate with increasing concentrations of BA and to produce callus and poorer quality shoots in the presence of NAA and the absence of BA. The response to BA and NAA was similar among 3 genotypes examined. A comparison of BA and N6-(2-isopentenyladenine) (2iP) showed that 2iP was not effective in promoting shoot proliferation. Shoot tips rooted in the absence of growth regulators or in the presence of low concentrations of indole-3-butyric acid (IBA). Plantlets were successfully acclimated to greenhouse conditions. 相似文献
10.