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1.
Summary Although serological reactivity to human papillomavirus type 16 (HPV-16) proteins has been demonstrated in patients with invasive cervical carcinoma, the degree of seroreactivity to these proteins in women with preinvasive disease and its relationship to the HPV type associated with the disease are unclear. We obtained sera from 27 women undergoing cone biopsy for cervical precursor lesions and 22 controls and analyzed seroreactivity by Western blot to fusion proteins containing portions of the HPV-16 E4, L1 and L2 open-reading frames (ORFs). Positives were analyzed by scanning densitometry and intensity values for each case plotted relative to controls. Cervical biopsy specimens from patients were analyzed for HPV-16 nucleic acids by DNA · DNA in situ hybridization. Mean intensity values for seroreactivity to the pATH-E4 protein approached significance (P = 0.058) and a significantly higher proportion of cases vs controls registered values over 4.0 for pATH-E4 (26% vs 4.5%;P = 0.04) and pATH-L2 (48% vs 18%;P = 0.03) proteins. A significantly higher mean intensity value for E4 was observed for cases containing HPV-16 DNA vs HPV-16 negative cases or controls. Thus, seroreactivity to HPV-16-derived proteins may be more common in women with preinvasive cervical disease, and for some protein targets (E4) may indicate a relatively type-specific response.Supported in part by grants from the National Cancer Institute [CA 47676 (C.P.C.)], American Cancer Society [MV-395 (C.P.C.)] and an institutional support grant (J.K.R.). Dr. Crum is a recipient of a Physician Scientist Award from the National Institute of Allergy and Infectious Disease (AI00628)  相似文献   
2.
Regulation of phytoplankton dynamics in a Laurentian Great Lakes estuary   总被引:1,自引:1,他引:0  
The composition and dynamics of phytoplankton populations were examined in Old Woman Creek estuary, Lake Erie (USA). The centric bacillariophytes,Cyclotella atomus Hust.,Cyclotella meneghiniana Kütz., andAulacoseira alpigena (Grun.) Krammer, and the cryptophytes,Cryptomonas erosa Ehren. andRhodomonas minuta var. nannoplanctonica Skuja, dominated the phytoplankton most of the year. Chlorophytes, euglenophytes, and cyanophytes were observed less frequently. Estuarine and Lake Erie phytoplankton were considered distinct populations; lake taxa were largely confined to the estuary mouth and present only in low biomass. Maxima and minima of estuarine phytoplankton coincided with meteorological and hydrological forcing in the form of rainfall and subsequent storm-water inflows, respectively. Distinct population dynamics between the upper and lower estuary following storm events were attributed to the presence/absence of refugia serving as a source for repopulation by opportunistic taxa, fluctuating light conditions in the water column resulting from influx of particulate matter and resuspension of bottom sediments, and nutrient inputs associated with surface runoff and sub-surface interflow. Additionally, agricultural herbicides introduced by storm-water inflows potentially may affect and/or control the growth and physiological responses of individual taxa.  相似文献   
3.
Our previous studies have implied that prostaglandins inhibit cell growth independent of cAMP. Recent reports, however, have suggested that prostaglandin arrest of the cell cycle may be mediated through protein kinase A. In this report, in order to eliminate the role of c-AMP in prostaglandin mediated cell cycle arrest, we use the-49 lymphoma variant (cyc?) cells that lack adenylate cyclase activity. We demonstrate that dimethyl prostaglandin A1 (dmPGA1) inhibits DNA synthesis and cell growth in cyc? cells. DNA synthesis is inhibited 42% by dmPGA1 (50 μM) despite the fact that this cell line lacks cellular components needed for cAMP generation. The ability to decrease DNA synthesis depends upon the specific prostaglandin structure with the most effective form possessing the α,β unsaturated ketone ring. Dimethyl PGA1 is most effective in inhibiting DNA synthesis in cyc? cells, with prostaglandins PGE1 and PGB1 being less potent inhibitors of DNA synthesis. DmPGE2 caused a significant stimulation of DNA synthesis. S-49 cyc- variant cells exposed to (30–50 μm) dmPGA1, arrested in the G1 phase of the cell cycle within 24 h. This growth arrest was reversed when the prostaglandin was removed from the cultured cells; growth resumed within hours showing that this treatment is not toxic. The S-49 cyc? cells were chosen not only for their lack of adenylate cyclase activity, but also because their cell cycle has been extensively studied and time requirements for G1, S, G2, and M phases are known. Within hours after prostaglandin removal the cells resume active DNA synthesis, and cell number doubles within 15 h suggesting rapid entry into S-phase DNA synthesis from the G1 cell cycle block. The S-49 cyc? cells are known to have a G1/S boundary through M phase transition time of 14.8 h, making the location of the prostaglandin cell cycle arrest at or very near the G1/S interface. The oncogenes, c-fos and c-myc which are normally expressed during G1 in proliferating cells have a 2–3 fold enhanced expression in prostaglandin G1 arrested cells. These data using the S-49 variants demonstrate that dmPGA1 inhibits DNA synthesis and arrests the cell cycle independent of cAMP-mediated effects. The prostaglandin arrested cells maintain the gene expression of a G1 synchronous cell which suggests a unique molecular mechanism for prostaglandin action in arresting cell growth. These properties indicate that this compound may be an effective tool to study molecular mechanisms of regulation of the cell cycle.  相似文献   
4.
The monoterpene derivative, 2-methylisoborneol (MIB), is produced by many blue-green algae and often is responsible for the “musty” taste/odor in aquaculturally raised finfish and potable water supplies. Although previous researchers have suggested that taste/odor metabolites are partitioned among cell constituents and that coregulation with pigment biosynthesis occurs, no structural evidence for these hypotheses exists. MIB was localized in cells of Oscillatoria limosa (Roth) Agardh at the ultrastructural level using standard gold-labeled antibody techniques. There was no apparent relationship between age of the cells and MIB synthesis; cells that were and were not undergoing active division had similar amounts of MIB label. There was no consistent partitioning of MIB label within cells. However, occasionally, specific label was observed along photosynthetic lamellae, suggesting a potential linkage of MIB synthesis and/or binding to the pigment systems.  相似文献   
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The origin of human triploidy is controversial. Early cytogenetic studies found the majority of cases to be paternal in origin; however, recent molecular analyses have challenged these findings, suggesting that digynic triploidy is the most common source of triploidy. To resolve this dispute, we examined 91 cases of human triploid spontaneous abortions to (1) determine the mechanism of origin of the additional haploid set, and (2) assess the effect of origin on the phenotype of the conceptus. Our results indicate that the majority of cases were diandric in origin because of dispermy, whereas the maternally-derived cases mainly originated through errors in meiosis II. Furthermore, our results indicate a complex relationship between phenotype and parental origin: paternally-derived cases predominate among "typical" spontaneous abortions, whereas maternally-derived cases are associated with either early embryonic demise or with relatively late demise involving a well-formed fetus. As the cytogenetic studies relied on analyses of the former type of material and the molecular studies on the latter sources, the discrepancies between the data sets are explained by differences in ascertainment. In studies correlating the origin of the extra haploid set with histological phenotype, we observed an association between paternal-but not maternal-triploidy and the development of partial hydatidiform moles. However, only a proportion of paternally derived cases developed a partial molar phenotype, indicating that the mere presence of two paternal genomes is not sufficient for molar development.  相似文献   
7.
High-throughput fluorescent intercalator displacement (HT–FID) was adapted to the semi-automated screening of a commercial compound library containing 60,000 molecules resulting in the discovery of cytotoxic DNA-targeted agents. Although commercial libraries are routinely screened in drug discovery efforts, the DNA binding potential of the compounds they contain has largely been overlooked. HT–FID led to the rapid identification of a number of compounds for which DNA binding properties were validated through demonstration of concentration-dependent DNA binding and increased thermal melting of A/T- or G/C-rich DNA sequences. Selected compounds were assayed further for cell proliferation inhibition in glioblastoma cells. Seven distinct compounds emerged from this screening procedure that represent structures unknown previously to be capable of targeting DNA leading to cell death. These agents may represent structures worthy of further modification to optimally explore their potential as cytotoxic anti-cancer agents. In addition, the general screening strategy described may find broader impact toward the rapid discovery of DNA targeted agents with biological activity.  相似文献   
8.
Adaptation to environment is the cornerstone of ecological genetics. The subject of this study is a wild relative of the sequenced and annotated model plant species, Arabidopsis thaliana. Caulanthus amplexicaulis var. barbarae lives on serpentine soils, known for high concentrations of heavy metals and low concentrations of essential plant macronutrients, and provides a compelling example of an organism’s adaptation to environment. We constructed an F2 linkage map, using a cross to the nonserpentine sister taxon, C. amplexicaulis var. amplexicaulis. C. amplexicaulis is a member of a highly diverse set of taxa (within the tribe Thelypodieae), described here as the ‘Streptanthoid Complex’ that are adapted to a broad range of environments, yet share a common n = 14 chromosome number and likely arose by a recent radiation. The linkage map consists of 97 polymorphic microsatellite markers, and 40 exon‐primed intron‐crossing markers based on A. thaliana exon sequences and Brassica ESTs. The map covers 14 linkage groups and has a total length of 1513 cM. Both the patterns of marker segregation and the comparative map indicate that C. amplexicaulis is a diploid organism with a compact genome. All exon‐primed intron‐crossing markers, and an unexpectedly large number of microsatellite markers (83%), had significant similarity to the A. thaliana genome, facilitating the development of a comparative genome map. As a proof of principle, we used the comparative map to identify candidate genes underlying differences in sepal colour between the two parent taxa. We demonstrate that the genomic tools developed here will be portable throughout the Streptanthoid Complex.  相似文献   
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10.
Evens  T. J.  Wee  J. L.  Kirkpatrick  G. J.  Millie  D. F.  & Boihem  L. L. 《Journal of phycology》2003,39(S1):14-15
A yearlong study (2002–2003) was conducted in the Lake Pontchartrain Estuary (LPE) of Southeast Louisiana in order to examine the temporal and spatial variability of phytoplankton biomass and community dynamics in relation to nutrients, light climate and other abiotic parameters. Variability was assessed through a north-south transect across the estuary and at five of the major tributaries of the LPE at bi-weekly intervals. Phytoplankton pigmentation was analyzed by HPLC and used to calculate biomass (as chlorophyll a) and to determine the relative abundances of phylogenetic groups and taxa (via CHEMTAX). Microscopic analyses of select samples were used to verify the efficacy of the CHEMTAX method in the waters of the LPE. Water-column up-/down-welling irradiance (PAR) and colored dissolved organic matter (CDOM) measurements were used to characterize the light climate. Results indicate that LPE phytoplankton biomass and community composition are: 1) highly variable at the spatial and temporal scales of this study, 2) can significantly impact the light field of the LPE, and 3) are influenced by macro-nutrient ratios.  相似文献   
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