排序方式: 共有22条查询结果,搜索用时 15 毫秒
1.
Vankelecom Hugo Seuntjens Eve Hauspie Annelies Denef Carl 《Journal of biomedical science》2003,10(6):805-812
We previously reported that transgenic ablation of gonadotrophs results in impaired development of cells immunostainable for prolactin (PRL) but not of cells immunostainable for growth hormone (GH) or proopiomelanocortin (POMC) in pituitary of newborn mice. The question remained whether this reduction in PRL protein is a reflection of reduced PRL mRNA expression, or whether this regulation is only situated at the translational level. We therefore generated a new series of transgenic mice in which gonadotrophs were ablated by diphtheria toxin A targeting, and analyzed hormone mRNA levels instead of hormone protein around the day of birth. Pituitary mRNA expression levels of luteinizing hormone- (LH), PRL and GH were quantified using real-time TaqMan RT-PCR. Of the 13 transgenic mice obtained, 8 showed a clear-cut reduction (ranging from 62 to 98%) in LH mRNA levels. PRL mRNA values were significantly reduced in the transgenic mice (p=0.0034), while GH mRNA expression was unaffected (p=0.93). An additional observation was that female newborn mice produce 5 times more LH mRNA than male mice whereas no sex difference was observed for expression levels of PRL and GH mRNA. Moreover, in the wild-type mice, LH mRNA expression was 20-fold higher than GH mRNA expression which in turn was 500- to 1,000-fold higher than PRL mRNA expression, suggesting a low expression level of the PRL gene at birth. In conclusion, the present data support the hypothesis that embryonic development of PRL gene expression is stimulated by gonadotrophs. 相似文献
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Seuntjens E Hauspie A Roudbaraki M Vankelecom H Denef C 《Archives of physiology and biochemistry》2002,110(1-2):12-15
Cells displaying combined expression of different pituitary hormone genes (further referred to as 'multi-hormone mRNA cells') were identified in normal rat and mouse pituitary by single cell RT-PCR. These cells do not seem to produce or store all the respective hormones the mRNAs encode for. The cells are already developed at day 16 of embryonic life (E16) in the mouse. Different peptides, such as gamma3-melanocyte-stimulating hormone (gamma3-MSH) and gonadotropin-releasing hormone (GnRH), affect different subsets of these cells. In culture, estrogen and GnRH increase the number of 'multi-hormone mRNA cells' that contain prolactin (PRL) mRNA or mRNA of the alpha-subunit of the glycoprotein hormones (alpha-GSU) but not the number of 'multi-hormone mRNA cells' not containing PRL or alpha-GSU mRNA. 'Multi-hormone mRNA cells' may function as 'reserve cells' in which a particular hormone mRNA may be translated under a particular physiological condition demanding a rapid increase of that hormone. 相似文献
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Chen J Crabbe A Van Duppen V Vankelecom H 《Molecular endocrinology (Baltimore, Md.)》2006,20(12):3293-3307
Recently, we discovered in the adult anterior pituitary a subset of cells with side population (SP) phenotype, enriched for expression of stem/progenitor cell-associated factors like Sca1, and of Notch1 and Hes (hairy and enhancer of split) 1, components of the classically developmental Notch pathway. In the present study, we elaborated the expression of the Notch signaling system in the postnatal pituitary, and examined its functional significance within the SP compartment. Using RT-PCR, we detected in the anterior pituitary of adult mouse the expression of all four vertebrate Notch receptors, as well as of Hes1, 5, and 6, key downstream targets and effectors of Notch. All Notch receptors, Hes1 and Hes5 were measured at higher mRNA levels in the Sca1(high) SP than in the main population (MP) of differentiated hormonal cells. In contrast, Hes6, known as an inhibitor of Hes1, was more abundant in the MP. Cells with SP phenotype, enriched for Sca1(high) expression, were detected throughout postnatal life. Their proportion was higher in immature mice, but did not change from adult (8 wk old) to much older age (1 yr old). Notch pathway expression was higher in the Sca1(high) SP than in the MP at all postnatal ages analyzed. Functional implication of Notch signaling in the SP was investigated in reaggregate cultures of adult mouse anterior pituitary cells. Treatment with the gamma-secretase inhibitor DAPT down-regulated Notch activity and reduced the proportion of SP cells. Activation of Notch signaling with the conserved DSL motif of Notch ligands, or with a soluble ligand, caused a rise in SP cell number, at least in part due to a proliferative effect. The SP also expanded in proportion when aggregates were treated with leukemia-inhibitory factor, basic fibroblast growth factor, and epidermal growth factor, again at least partly accounted for by a mitogenic action. These intrapituitary growth factors all activated Notch signaling, and DAPT abrogated the expansion of the SP by basic fibroblast growth factor and leukemia-inhibitory factor, thus exposing a possible cross talk. In conclusion, we show that the Notch pathway, typically situated in embryogenesis, is also present and active in the postnatal pituitary, that it is particularly expressed within the SP independent of age, and that it plays a role in the regulation of SP abundance. Whether our data indicate that Notch regulates renewal and fate decisions of putative stem/progenitor cells within the pituitary SP as found in other tissues, remains open for further exploration. 相似文献
4.
Piasecka A Souffreau C Vandepitte K Vanysacker L Bilad RM Bie TD Hellemans B Meester LD Yan X Declerck P Vankelecom IF 《Biofouling》2012,28(2):225-238
Membrane biofouling was investigated during the early stages of filtration in a laboratory-scale membrane bioreactor operated on molasses wastewater. The bacterial diversity and composition of the membrane biofilm and activated sludge were analyzed using terminal restriction fragment length polymorphism coupled with 16S rRNA clone library construction and sequencing. The amount of extracellular polymeric substances produced by bacteria was investigated using spectroscopic methods. The results reveal that the bacterial community of activated sludge differs significantly from that of the membrane biofilm, especially at the initial phase. Phylogenetic analysis based on 16S rRNA gene sequences identified 25 pioneer OTUs responsible for membrane surface colonization. Also, the relationship between the identified bacterial strains and the system specifications was explored. 相似文献
5.
Bacterial community analysis of activated sludge: an evaluation of four commonly used DNA extraction methods 总被引:1,自引:0,他引:1
Louise Vanysacker Steven A. J. Declerck Bart Hellemans Luc De Meester Ivo Vankelecom Priscilla Declerck 《Applied microbiology and biotechnology》2010,88(1):299-307
The effectiveness of three commercially available direct DNA isolation kits (Mobio, Fast, Qiagen) and one published direct
DNA extraction protocol (Bead) for extracting bacterial DNA from different types of activated sludge was investigated and
mutually compared. The DNA quantity and purity were determined using real-time PCR targeting the bacterial 16S rDNA gene.
Microbial community fingerprints were assessed by automated ribosomal intergenic spacer analysis. The resulting community
profiles were analyzed with canonical correspondence analysis. Our results clearly demonstrate that direct DNA extraction
methods can significantly influence the DNA quantity, purity, and observed community patterns of microbiota in activated sludge.
Fast and Mobio generated high amounts of good quality DNA compared to Bead and Qiagen. Mobio also resulted in the detection
of the highest number of species while Fast scored the best in discriminating between the community patterns of different
activated sludge types. With respect to the characterization of community profiles, our analyses demonstrated a strong sludge
type dependent variability among methods. Taking into account our results, we recommend Fast as the most suitable DNA extraction
method for activated sludge samples used for bacterial community studies. 相似文献
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Randi T Garmo Steinar Waage Ståle Sviland Britt IF Henriksen Olav Østerås Olav Reksen 《Acta veterinaria Scandinavica》2010,52(1):11
Background
The objectives of this study were to investigate whether there were differences between Norwegian Red cows in conventional and organic farming with respect to reproductive performance, udder health, and antibiotic resistance in udder pathogens. 相似文献10.
Wouters J Stas M Govaere O Van den Eynde K Vankelecom H van den Oord JJ 《Pigment cell & melanoma research》2012,25(4):454-465
Despite recent advances in melanoma therapy, disseminated melanoma still lacks effective treatment, and recurrence of the tumor frequently occurs, even after high-dose chemotherapy. The mechanisms responsible for this chemoresistance or for the formation of new relapses remain poorly understood. Using a human 'model', in which the isolated limb is perfused with high doses of the chemotherapeutic melphalan (ILP), we identified a five-gene set (ATF3, CYR61, IER5, IL6, and PTGS2) of stress-induced genes that was consistently upregulated after ILP in all in-transit metastatic melanoma samples as well as in three melphalan-treated melanoma cell lines. Early post-ILP relapses retained these elevated expressions, whereas the expression of these genes returned to their original levels in late post-ILP recurrences. In addition, we identified upregulation of these genes in the A375 cell line's side population (SP) and melanospheres, established methods to enrich for candidate cancer stem cells (CSCs), which are considered chemoresistant and tumorigenic, and thus proposed to be responsible for tumor relapse. Our data identify an immediate and short-term upregulation of early stress-responsive genes that are potentially linked to chemoresistance and CSCs. 相似文献