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We have examined the expression of three paralogous Hox genes from E11.5 through E15.5 in the mouse spinal cord. These ages coincide with major phases of spinal cord neurogenesis, neuronal differentiation, cell migration, gliogenesis, and motor neuron cell death. The three genes, Hoxa10, Hoxc10, and Hoxd10, are all expressed in the lumbar spinal cord and have distinct expression patterns. Mutations in these three genes are known to affect motor neuron patterning. All three genes show lower levels of expression at the rostral limits of their domains, with selective regions of higher expression more caudally. Hoxa10 and Hoxd10 expression appears confined to postmitotic cell populations in the intermediate and ventral gray, while Hoxc10 is also expressed in proliferating cells in the dorsal ventricular zone. Hoxc10 and Hoxd10 expression is clearly excluded from the lateral motor columns at rostral lumbar levels but is present in this region more caudally. Double labeling demonstrates that Hoxc10 expression is correlated with ventrolateral LIM gene expression in the caudal part of the lumbar spinal cord. 相似文献
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The trefoil factor (TFF) family, which comprises TFF1, TFF2 and TFF3, plays an essential role in epithelial regeneration within the gastrointestinal tract. All three TFFs are present in human saliva; TFF3 is the predominant trefoil peptide. Little is known about the expression and tissue distribution of TFFs in rats, which are commonly used as a model system for human studies. We investigated the localization of the TFF genes that encode secretory peptides in rat submandibular glands (SMG). All three TFFs were expressed in rat SMG, although their location varied. Substantial amounts of TFF1 were detected only in the cytoplasm of epithelial cells in the SMG granular convoluted tubules (GCT), while TFF2 and TFF3 were widely distributed in the cytoplasm of epithelial cells of intercalated ducts (ID), striated ducts (SD) and interlobular ducts (ILD). The three TFFs also were detected especially in the lumens of the SD and ILD. Semi-quantitative RT-PCR and in situ hybridization experiments confirmed TFF1, TFF2 and TFF3 mRNA expressions in the SMG. Greater expression of TFF peptides and mRNA was observed in male rats than in females. The broad expression of TFFs in rat SMG cells and lumens suggests that TFFs function in this organ by their secretion into the duct lumens. We also found differences in TFF expression profiles between rat and human SMG; therefore, caution should be exercised when using rats as a model for human TFF studies. 相似文献
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A genic male sterile Chinese cabbage, Brassica campestris L. ssp. chinensis Makino, was examined using cytological and cytochemical methods to characterize the process of pollen abortion in this plant.
Thick sections of both fertile and sterile anthers at different developmental stages were stained using Toluidine Blue O,
Periodic Acid-Schiff’s (PAS) reaction and Sudan Black B to detect cytochemical changes that may occur in the distribution
of insoluble polysaccharide and lipid storage bodies. Pollen abortion in sterile anthers occurs at an early stage of microspore
development. During early microspore development, reductions in the number of starch grains in the connective tissue of fertile
anthers coincide with the accumulation of starch grains in cells of the anther wall. In the late microspore stage, a large
vacuole forms in the microspore, and tapetal cells synthesize and accumulate lipid droplets. The cellular organization of
tapetal cells in sterile anthers appears similar to that in fertile anthers, except for the absence of lipid droplets in cells
of sterile anthers and diffusely labeled tapetal polysaccharides, suggesting defects in nutrient storage.
Supported by National Natural Science Foundation of CHINA (30170060) 相似文献
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Batoul Y Abdallah Steven D Horne Joshua B Stevens Guo Liu Andrew Y Ying Barbara Vanderhyden Stephen A Krawetz Root Gorelick Henry HQ Heng 《Cell cycle (Georgetown, Tex.)》2013,12(23):3640-3649
Multi-level heterogeneity is a fundamental but underappreciated feature of cancer. Most technical and analytical methods either completely ignore heterogeneity or do not fully account for it, as heterogeneity has been considered noise that needs to be eliminated. We have used single-cell and population-based assays to describe an instability-mediated mechanism where genome heterogeneity drastically affects cell growth and cannot be accurately measured using conventional averages. First, we show that most unstable cancer cell populations exhibit high levels of karyotype heterogeneity, where it is difficult, if not impossible, to karyotypically clone cells. Second, by comparing stable and unstable cell populations, we show that instability-mediated karyotype heterogeneity leads to growth heterogeneity, where outliers dominantly contribute to population growth and exhibit shorter cell cycles. Predictability of population growth is more difficult for heterogeneous cell populations than for homogenous cell populations. Since “outliers” play an important role in cancer evolution, where genome instability is the key feature, averaging methods used to characterize cell populations are misleading. Variances quantify heterogeneity; means (averages) smooth heterogeneity, invariably hiding it. Cell populations of pathological conditions with high genome instability, like cancer, behave differently than karyotypically homogeneous cell populations. Single-cell analysis is thus needed when cells are not genomically identical. Despite increased attention given to single-cell variation mediated heterogeneity of cancer cells, continued use of average-based methods is not only inaccurate but deceptive, as the “average” cancer cell clearly does not exist. Genome-level heterogeneity also may explain population heterogeneity, drug resistance, and cancer evolution. 相似文献
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Brian G. Drew Habib Hamidi Zhenqi Zhou Claudio J. Villanueva Susan A. Krum Anna C. Calkin Brian W. Parks Vicent Ribas Nareg Y. Kalajian Jennifer Phun Pedram Daraei Heather R. Christofk Sylvia C. Hewitt Kenneth S. Korach Peter Tontonoz Aldons J. Lusis Dennis J. Slamon Sara A. Hurvitz Andrea L. Hevener 《The Journal of biological chemistry》2015,290(9):5566-5581
Obesity is associated with increased breast cancer (BrCA) incidence. Considering that inactivation of estrogen receptor (ER)α promotes obesity and metabolic dysfunction in women and female mice, understanding the mechanisms and tissue-specific sites of ERα action to combat metabolic-related disease, including BrCA, is of clinical importance. To study the role of ERα in adipose tissue we generated fat-specific ERα knock-out (FERKO) mice. Herein we show that ERα deletion increased adipocyte size, fat pad weight, and tissue expression and circulating levels of the secreted glycoprotein, lipocalin 2 (Lcn2), an adipokine previously associated with BrCA development. Chromatin immunoprecipitation and luciferase reporter studies showed that ERα binds the Lcn2 promoter to repress its expression. Because adipocytes constitute an important cell type of the breast microenvironment, we examined the impact of adipocyte ERα deletion on cancer cell behavior. Conditioned medium from ERα-null adipocytes and medium containing pure Lcn2 increased proliferation and migration of a subset of BrCA cells in culture. The proliferative and promigratory effects of ERα-deficient adipocyte-conditioned medium on BrCA cells was reversed by Lcn2 deletion. BrCA cell responsiveness to exogenous Lcn2 was heightened in cell types where endogenous Lcn2 expression was minimal, but components of the Lcn2 signaling pathway were enriched, i.e. SLC22A17 and 3-hydroxybutyrate dehydrogenase (BDH2). In breast tumor biopsies from women diagnosed with BrCA we found that BDH2 expression was positively associated with adiposity and circulating Lcn2 levels. Collectively these data suggest that reduction of ERα expression in adipose tissue promotes adiposity and is linked with the progression and severity of BrCA via increased adipocyte-specific Lcn2 production and enhanced tumor cell Lcn2 sensitivity. 相似文献
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Natural diets commonly exploited by the flies are animal manures including production from the poultry and livestock facilities. The larvae of the common filth flies such as Musca domestica and Sarcophaga dux are known as voracious feeders and may thus be used to convert manures into non-polluted residue. This study was conducted to observe the impact on flies' growth rate and capability of the larvae to process animal manures using chicken, goat and cow manures. One hundred newly hatched larvae of M. domestica and S. dux were introduced separately into 150?g manures under laboratory conditions. The initial wet mass and larvae length were recorded while mortality rate and dry mass were measured after the larvae were placed into the manures. The results showed that the manure types give significant effects (p?<?.05) on the growth of M. domestica and S. dux larvae. Cow manures and chicken manures contributed the highest growth for M. domestica and S. dux respectively. This result confirmed by the mean increment in wet mass and larvae length. In contrast, M. domestica greatly reduced 59.9?±?4% chicken manures while 25.0?±?1.8% goat manures reduced by S. dux. The potential of M. domestica and S. dux larvae to reduce animal waste products were further discussed in this study. 相似文献
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Isolation of two populations of sperm cells and microelectrophoresis of pairs of sperm cells from pollen tubes of tobacco (Nicotiana tabacum) 总被引:1,自引:1,他引:0
Prior research has indicated that the two sperm cells of Nicotiana tabacum are dimorphic, suggesting that they may participate in preferential fertilization during in vivo fusion with the egg and
central cells. To probe the mechanism of potential preferential fertilization in this plant, it will be necessary to use modern
sensitive molecular techniques. For this purpose, two individual populations of two sperm cells, constituting the Svn (associated
with the vegetative nucleus) and Sua (unassociated with the vegetative nucleus), were isolated in the thousands from tobacco
pollen tubes with a micromanipulator as a preliminary step toward research on gametic recognition using molecular techniques.
Microelectrophoresis of paired sperm cells from a single pollen tube was conducted at different developmental stages. Sperm
cells isolated from 1-, 2-, 3- and 4-cm stylar lengths migrated to the negative pole, with the Sua displaying significantly
greater electrophoretic mobility than the Svn, reflecting a more positively charged cell surface on the Sua. The sperm cells
isolated from 1-cm style are very sensitive to electron potential in an electrophoretic field, presumably reflecting that
they are still in a young state. Differences in cell surface charge between the Sua and Svn may be related with cell fate
during fertilization.
Supported by National Natural Science Foundation of CHINA (30170060) 相似文献
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Cheung J Wilson MD Zhang J Khaja R MacDonald JR Heng HH Koop BF Scherer SW 《Genome biology》2003,4(8):R47