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61.
Yoshito Nagano Toru Fukushima Kazuo Okemoto Keiichiro Tanaka David DL Bowtell Ze'ev A Ronai John C Reed Shu-ichi Matsuzawa 《Cell cycle (Georgetown, Tex.)》2011,10(15):2592-2602
p27kip1 has been implicated in cell cycle regulation, functioning as an inhibitor of cyclin-dependent kinase activity. In addition, p27 was also shown to affect cell migration, with accumulation of cytoplasmic p27 associated with tumor invasiveness. However, the mechanism underlying p27 regulation as a cytoplasmic protein is poorly understood. Here we show that glucose starvation induces proteasome-dependent degradation of cytoplasmic p27, accompanied by a decrease in cell motility. We also show that the glucose limitation-induced p27 degradation is regulated through an ubiquitin E3 ligase complex involving Siah1 and SIP/CacyBP. SIP−/− embryonic fibroblasts have increased levels of cytosolic p27 and exhibit increased cell motility compared with wild-type cells. These observations suggest that the Siah1/SIP E3 ligase complex regulates cell motility through degradation of p27.Key words: p27kip1, Siah1, SIP, glucose starvation, cell migration 相似文献
62.
63.
The impact of gender and/or hormone variations on a wide variety of neural functions makes the choice between studying males or females (or both) of a given species difficult. Although female rats are widely used experimentally, few studies control for the stage of estrus. More detailed information about how to distinguish the various stages of the estrous cycle is needed. For the present study, vaginal smears were obtained once a day and stained using an adaptation of the Papanicolaou (PAP) procedure. Images are provided of unstained “wet” samples and the corresponding PAP stained smears illustrating the cellular profile for each stage of the cycle as well as post-ovariectomy. The different cell populations across the cycle were quantified and ratios determined to show trends between the predominant and other cell types in each stage of the estrous cycle. Both stained and unstained images and cell quantification data provide valuable guidelines for distinguishing the stages of the estrous cycle. 相似文献
64.
Typical preparation of seed samples for infrared (IR) microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4° C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes of analysis performed well in different regions of the spectrum. The mode of analysis (transmission vs. transmission-reflection) should be based on the components of greatest interest in the sample. 相似文献
65.
Shomari DL Zack-Williams Peter E Butler Deepak M Kalaskar 《World journal of stem cells》2015,7(1):51-64
Unlike central nervous system neurons; those in the peripheral nervous system have the potential for full regeneration after injury. Following injury, recovery is controlled by schwann cells which replicate and modulate the subsequent immune response. The level of nerve recovery is strongly linked to the severity of the initial injury despite the significant advancements in imaging and surgical techniques. Multiple experimental model shave been used with varying successes to augment the natural regenerative processes which occur following nerve injury. Stem cell therapy in peripheral nerve injury may be an important future intervention to improve the best attainable clinical results. In particular adipose derived stem cells(ADSCs) are multipotent mesenchymal stem cells similar to bone marrow derived stem cells, which are thought to have neurotrophic properties and the ability to differentiate into multiple lineages. They are ubiquitous within adipose tissue; they can form many structures resembling the mature adult peripheral nervous system. Following early in vitro work; multiple small and large animal in vivo models have been used in conjunction with conduits, autografts and allografts to successfully bridge the peripheral nerve gap. Some of the ADSC related neuroprotective and regenerative properties have been elucidated however much work remains before a model can be used successfully in human peripheral nerve injury(PNI). This review aims to provide a detailed overview of progress made in the use of ADSC in PNI, with discussion on the role of a tissue engineered approach for PNI repair. 相似文献
66.
Stable expression of mammalian beta 1,4-galactosyltransferase extends the N-glycosylation pathway in insect cells 总被引:3,自引:2,他引:3
An established lepidopteran insect cell line (Sf9) was cotransfected with
expression plasmids encoding neomycin phosphotransferase and bovine beta
1,4-galactosyltransferase. Neomycin-resistant transformants were selected,
assayed for beta 1,4-galactosyltransferase activity, and the transformant
with the highest level of enzymatic activity was characterized. Southern
blots indicated that this transformed Sf9 cell derivative contained
multiple copies of the galactosyltransferase- encoding expression plasmid
integrated at a single site in its genome. One-step growth curves showed
that these cells supported normal levels of baculovirus replication.
Baculovirus infection of the transformed cells stimulated beta
1,4-galactosyltransferase activity almost 5-fold by 12 h postinfection.
This was followed by a gradual decline in activity, but the infected cells
still had about as much activity as uninfected controls as late as 48 h
after infection and they were able to produce a beta 1,4-galactosylated
virion glycoprotein during infection. Infection of the transformed cells
with a conventional recombinant baculovirus expression vector encoding
human tissue plasminogen activator also resulted in the production of a
galactosylated end-product. These results demonstrate that stable
transformation can be used to add a functional mammalian
glycosyltransferase to lepidopteran insect cells and extend their N-
glycosylation pathway. Furthermore, stably-transformed insect cells can be
used as modified hosts for conventional baculovirus expression vectors to
produce foreign glycoproteins with "mammalianized" glycans which more
closely resemble those produced by higher eucaryotes.
相似文献
67.
Microgeographic morphological variation across larval wood frog populations associated with environment despite gene flow 下载免费PDF全文
Amanda J. Zellmer 《Ecology and evolution》2018,8(5):2504-2517
Gene flow has historically been thought to constrain local adaptation; yet, recent research suggests that populations can diverge despite exchanging genes. Here I use a common garden experiment to assess the combined effects of gene flow and natural selection on morphological variation of 16 wood frog (Rana sylvatica) populations, a species known to experience divergent selection pressures in open‐ and closed‐canopy ponds across relatively small geographic scales. Wood frog tadpoles from different ponds showed significant morphological variation associated with canopy type with a trade‐off between tail length and body depth consistent with previous research. In contrast, neutral genetic differentiation of nine microsatellite loci as measured by Jost's D was not associated with canopy type, indicating no pattern of isolation by environment. Genetic structure analyses indicated some substructure across the 16 ponds (K = 4); however, three out of four assigned clusters included both open‐ and closed‐canopy ponds. Together, these results suggest that morphological divergence among these wood frog populations is occurring despite gene flow and that selection within these environments is strong. Furthermore, morphological variation among ponds differed across two sampling periods during larval development, demonstrating the importance of evaluating phenotypic divergence over multiple time periods and at a time relevant to the processes being studied. 相似文献
68.
JB Farinha DL Dos Santos G Bresciani LF Bard F de Mello ST Stefanello AA Courtes FAA Soares 《Biology of sport / Institute of Sport》2015,32(2):109-114
The aim of this study was to investigate the impact of moderate aerobic training on functional, anthropometric, biochemical, and health-related quality of life (HRQOL) parameters on women with metabolic syndrome (MS). Fifteen untrained women with MS performed moderate aerobic training for 15 weeks, without modifications of dietary behaviours. Functional, anthropometric, biochemical, control diet record and HRQOL parameters were assessed before and after the training. Despite body weight maintenance, the patients presented decreases in waist circumference (P = 0.001), number of MS components (P = 0.014), total cholesterol (P = 0.049), HDL cholesterol (P = 0.004), LDL cholesterol (P = 0.027), myeloperoxidase activity (P = 0.002) and thiobarbituric acid-reactive substances levels (P = 0.006). There were no differences in total energy, carbohydrate, protein and lipid intake pre- and post-training. Furthermore, improvements in the HRQOL subscales of physical functioning (P = 0.03), role-physical (P = 0.039), bodily pain (P = 0.048), general health (P = 0.046) and social functioning scoring (P = 0.011) were reported. Despite the absence of weight loss, aerobic training induced beneficial effects on functional, anthropometric, biochemical and HRQOL parameters in women with MS. 相似文献
69.
With the cancellation of fenamiphos in the near future, alternative nematode management tactics for plant-parasitic nematodes (PPN) on golf courses need to be identified. The use of entomopathogenic nematodes (EPN) has been suggested as one possible alternative. This paper presents the results of 10 experiments evaluating the efficacy of EPN at managing PPN on turfgrasses and improving turf performance. These experiments were conducted at various locations throughout Florida over the course of a decade. In different experiments, different EPN species were tested against different species of PPN. Separate experiments evaluated multiple rates and applications of EPN, compared different EPN species, and compared single EPN species against multiple species of PPN. In a few trials, EPN were associated with reductions in certain plant-parasite species, but in other trials were associated with increases. In most trials, EPN had no effect on plant parasites. Because EPN were so inconsistent in their results, we conclude that EPN are not acceptable alternatives to fenamiphos by most turf managers in Florida at this time. 相似文献
70.
Lisa?M?VallelyEmail author Angela?Kelly Martha?Kupul Ruthy?Neo Voletta?Fiya John?M?Kaldor Glen?DL?Mola Heather?Worth 《International breastfeeding journal》2013,8(1):6