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排序方式: 共有99条查询结果,搜索用时 9 毫秒
1.
Molecular characterization of a mucin-type antigen associated with human pancreatic cancer. The DU-PAN-2 antigen 总被引:3,自引:0,他引:3
M S Lan A Khorrami B Kaufman R S Metzgar 《The Journal of biological chemistry》1987,262(26):12863-12870
This work describes the molecular characterization of a human pancreatic cancer-associated antigen defined by a murine monoclonal antibody (DU-PAN-2). DU-PAN-2 antigen was isolated from a pancreatic adenocarcinoma cell line (HPAF) or patient's ascitic fluid, and the antigenic activity was monitored by competitive inhibition radioimmunoassay. Affinity chromatography and CsCl/guanidine HCl density gradient centrifugation were employed to remove other populations of mucin-type glycoproteins and noncovalently associated proteins, respectively. Three electrophoretically distinct components were detected by 1% agarose gel electrophoresis and were resolved by chromatography on Sepharose CL-4B. The major fraction (FII) was subjected to carbohydrate and amino acid analyses. The sum of threonine, serine, proline, glycine, and alanine comprised more than 50% of the amino acid residues. The saccharide units, O-glycosidically linked to the peptide via GalNAc, contained fucose, galactose, GlcNAc, GalNAc, and sialic acid. The total carbohydrate content of FI and FII was 80.8% and 77.4% by weight, respectively. The molecular weight of FII antigen showed two species of molecules of 1.45 X 10(6) and 4.59 X 10(6) by analytical sedimentation equilibrium. DU-PAN-2 antigen was susceptible to neuraminidase, pepsin, Pronase, and papain digestion. These results suggest that both protein components and sialic acid residues may play important roles in the binding of DU-PAN-2 antibody. 相似文献
2.
The phylogeny of the hominoid primates: a statistical analysis of the DNA-DNA hybridization data 总被引:1,自引:0,他引:1
Sibley and Ahlquist compared the single-copy nuclear DNA sequences of the
hominoid primates using DNA-DNA hybridization. From this data set they
estimated a phylogeny that clusters man and chimpanzees using a distance
Wagner procedure. However, no assessment of statistical confidence in this
estimated phylogeny was made, despite the fact that their data set contains
internal inconsistencies concerning the correct branching order. This paper
presents a modification of Pielou's Q- statistic that allows one to make
nonparametric tests of phylogenetic relationship from distance data. The
results of this analysis indicate that the estimated phylogeny of Sibley
and Ahlquist is without statistical significance owing to the internal
inconsistencies of the data set. A survey and additional analyses of other
types of molecular data indicate that the phylogeny that clusters
chimpanzees and gorillas and has the human lineage splitting off earlier is
statistically consistent with all the molecular data (including the DNA-DNA
hybridization data), whereas the phylogeny estimated by Sibley and Ahlquist
can be rejected at the 5% level using the data on restriction- endonuclease
sites in the mitochondrial genome.
相似文献
3.
Dr AR Holmes RD Cannon HF Jenkinson 《Journal of industrial microbiology & biotechnology》1995,15(3):208-213
The yeastCandida albicans coaggregates with a variety of streptococcal species, an interaction that may promote oral colonization by yeast cells.C. albicans andCandida tropicalis are the yeasts most frequently isolated from the human oral cavity and our data demonstrate that both these species bind toStreptococcus gordonii NCTC 7869 while two otherCandida species (Candida krusei andCandida kefyr) do not. Adherence ofC. albicans was greatest when the yeast had been grown at 30° C to mid-exponential growth phase. For 21 strains ofC. albicans there was a positive correlation between the ability to adhere toS. gordonii and adherence to experimental salivary pellicle. Whole saliva either stimulated or slightly inhibited adherence ofC. albicans toS. gordonii depending on the streptococcal growth conditions. The results suggest that the major salivary adhesins and coaggregation adhesins ofC. albicans are co-expressed. 相似文献
4.
Cytochrome P-448 (mol wt 55,000 Daltons) from rabbit liver was purified to a specific content of 16.6 nmol/mg. Mice were immunised with this preparation, their spleens removed and dissociated lymphocytes hybridised with myeloma cells. Four monoclonal antibodies against cytochrome P-448 were raised and partially characterised. All four antibodies interacted with cytochrome P-448 in intact microsomal fractions and selectively immunoadsorbed cytochrome P-448 from solubilised microsomal preparations. One of the antibodies inhibited benzo[a] pyrene hydroxylase activity in a reconstituted system, one had no effect on activity and two increased activity. The possible applications of such antibodies are discussed. 相似文献
5.
6.
DC Chhieng AR Frost S Niwas H Weiss WE Grizzle S Beeken 《Biotechnic & histochemistry》2013,88(1):25-36
Small biopsy samples are used increasingly to assess the biomarker expression for prognostic information and for monitoring therapeutic responses prior to and during neoadjuvant therapy. The issue of intratumor heterogeneity of expression of biomarkers, however, has raised questions about the validity of the assessment of biomarker expression based on limited tissue samples. We examined immunohistochemically the expression of HER-2neu (p185erbB-2), epidermal growth factor receptor (EGFR), Bcl-2, p53, and proliferating cell nuclear antigen (PCNA) in 30 breast carcinomas using archived, paraffin embedded tissue and determined the extent of intratumor heterogeneity. Each section was divided into four randomly oriented discrete regions, each containing a portion of the infiltrating carcinoma. For each tumor, the entire lesion and four regions were analyzed for the expression of these markers. Scores of both membrane and cytoplasmic staining of HER-2neu and EGFR, scores of cytoplasmic staining of Bcl-2, and scores of nuclear staining of both p53 and PCNA were recorded. The intensity of staining and the proportion of immunostained cells were determined. A semiquantitative immunoscore was calculated by determining the sum of the products of the intensity and corresponding proportion of stained tumor cells. We analyzed both invasive (IDC) and in situ (DCIS) carcinomas. The Wilcoxon signed-rank test was used for paired comparisons between overall and regional immunoscores and between overall and regional percentages of stained cells. Spearman's correlation coefficients were used to assess the level of agreement of overall biomarker expression with each of the regions. Generalized linear models were used to assess overall and pair-wise differences in the absolute values of percent changes between overall and regional expression of biomarkers. For IDCs, there were no statistically significant differences in the expression of the biomarkers in terms of either the percentage of cells staining or the immunoscores when comparing the entire tumor with each region except for the lower EGFR expression of arbitrarily selected region 1 and lower p53 expression of region 1 compared to that of the entire tumor section. For DCIS, there were no statistically significant differences in the expression of the biomarkers between the entire tumor and each region except in PCNA of region 2 compared to that of entire tumor section. Positive correlation of immunoscores was observed between the entire tumor and each region as well as across all four regions for IDC. Similar observations were noted with DCIS except for HER-2neu and PCNA. No statistically significant differences were observed in the absolute values of percent changes of biomarker expression between overall and the four regions for both DCIS and IDC. Therefore, no significant intratumor heterogeneity in the expression of HER-2neu, Bcl-2, and PCNA was observed in IDC. Minor regional variations were observed for EGFR and p53 in IDC. Similarly, no significant regional variation in the expression of markers was observed in DCIS except for PCNA. 相似文献
7.
Fereshteh Khorrami Oruj Valizadegan Maryam Forouzan Asmar Soleymanzade 《Archives Of Phytopathology And Plant Protection》2013,46(13-14):685-695
AbstractRed flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is a prominent pest of stored products particularly cereal flour. Since resistance of this pest to common chemical insecticides is well documented, we were examined the synergistic/antagonistic interaction between Satureja hortensis L., Trachyspermum ammi L., Ziziphora tenuior L., Cuminum cyminum L. and Foeniculum vulgare Miller essential oils, ethanolic extracts and powders with Diatomaceous earth (DE) against T. castaneum adults under laboratory conditions at 27 ± 1 °C, 65 ± 5% RH and continuous darkness. We assayed repellency of ethanolic extracts and essential oils of mentioned plants on the pest. Results showed that DE had high toxicity to the pest. Plant essential oils and ethanolic extracts (except ziziphora) synergized the performance of DE. Nevertheless, plant powders elicited antagonistic effects (except ziziphora that exhibited synergistic effect). The most repellent EO and extract was cumin which exhibited mean repellency value on adult insect equivalent to 92.58 and 51.47%, respectively. 相似文献
8.
GÖRAN I. V. KLOBUČAR MARTINA PODNAR MIŠEL JELIĆ DAMJAN FRANJEVIĆ MATEJ FALLER ANAMARIA ŠTAMBUK SANJA GOTTSTEIN VLADICA SIMIĆ IVANA MAGUIRE 《Freshwater Biology》2013,58(6):1089-1105
1. This study examines phylogeography and phylogeny of the threatened stone crayfish, Austropotamobius torrentium, in order to elucidate the role of the Dinaric Karst geology in shaping the evolutionary history and genetic diversity of aquatic fauna in the western Balkans. Mitochondrial 16S rRNA and COI genes were partially sequenced from 188 and 159 crayfish, respectively, sampled from 70 localities. Phylogenetic relationships were reconstructed using four methods of phylogenetic inference. Divergence times between phylogroups were estimated in a Bayesian framework, and their demographic history was examined using neutrality tests and mismatch distribution analysis. 2. Seven geographically localised phylogroups separated by pronounced genetic gaps were found. Five of them have a distribution range within the northern‐central Dinaric (NCD) region, while the remaining two include populations from the southern Balkans (SB) and central and south‐eastern Europe (CSE). The oldest divergence event separated two NCD lineages from the rest of populations in the Late Miocene or Early Pliocene. Divergences amongst the five NCD phylogroups and SB + CSE occurred in the Pliocene. The most recent split separated SB and CSE phylogroups during the Late Pliocene. For both genes, uncorrected pairwise divergences between most of the phylogroups (4.1–8.7% for COI and 1.6–4.8% for 16S rRNA) were of the same range as, or higher than, some of the interspecific distances previously reported for the genus Austropotamobius. 3. Geographically isolated and deeply divergent cryptic monophyletic phylogroups within A. torrentium in the NCD region arose in the course of intensification of Neotectonic movements during the Pliocene and the beginning of the Pleistocene and the development of karstification that has heavily fragmented the palaeohydrography of the area. The results confirm a gradual north–south expansion of stone crayfish during the pre‐Pleistocene that preceded the rapid northward post‐glacial re/colonisation of central Europe (CSE phylogroup) through the Danube drainage. 4. Austropotamobius torrentium comprises morphologically cryptic but molecularly distinct taxa. Considering the relatively small geographical areas they inhabit, the NCD phylogroups of stone crayfish should be given the highest conservation priority. 相似文献
9.
Burggren W Khorrami S Pinder A Sun T 《American journal of physiology. Regulatory, integrative and comparative physiology》2004,287(6):R1399-R1406
Normal aerobic metabolic rates persist in the early chicken embryo after elimination of cardiac output, but the dependence of tissue growth and differentiation on blood flow is unknown in these early stages. We partially ligated (25-50% occlusion) the ventricular outflow tract of Hamburger-Hamilton stage (HH) 16-18 embryos, producing a wide range of cardiac output. For the next approximately 48 h (to HH 24), we measured heart rate (HR), stroke volume (SV), and cardiac output (CO), as well as these growth indicators: eye diameter, chorioallantoic vessel density, and body mass. Acutely, HR declined with partial ligation (from 108 to 98 beats/min). Paradoxically, SV and CO decreased sharply in most embryos but increased in others, collectively producing the desired large variation (up to 25-fold) in CO and permitting assessment of tissue growth over a very large range of blood perfusion. Eye diameter doubled (from 0.6 to 1.2 mm) with development from HH 16 to HH 24, but within a developmental cohort there was no significant correlation between eye diameter and CO over a 25-fold range of CO. Similarly, chorioallantoic membrane vessel index was independent of CO over the CO range at all stages. Finally, body mass increase during development was not significantly affected by partial conal truncal ligation. Collectively, these data suggest that normal eye and vessel growth and body mass accumulation occur independent of their rate of blood perfusion, supporting the hypothesis of prosynchronotropy-that the heart begins to beat and generate blood flow in advance of the actual need for convective blood flow to tissues. 相似文献
10.