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41.
Regulation of cellular adhesion molecule expression in murine oocytes, peri-implant ation and post-implantation embryos 总被引:2,自引:0,他引:2
DAVID P LU LINA TIAN CHRIS O'''' NEILL NICHOLAS JC KING Department of Pathology University of Sydney NSW AustraliaHuman Reproduction Unit Department of Physiology University of Sydney Royal North Shore Hospital NSW Australia 《Cell research》2002,(Z2)
Expression of the adhesion molecules, ICAM-1, VCAM-1, NCAM, CD44, CD49d (VLA-4, a chain), and CDlla (LFA-1, a chain) on mouse oocytes, and pre- and peri-implantation stage embryos was examined by quantitative indirect immunofluorescence microscopy. ICAM-1 was most strongly expressed at the oocyte stage, gradually declining almost to undetectable levels by the expanded blastocyst stage. NCAM, also expressed maximally on the oocyte, declined to undetectable levels beyond the morula stage. On the other hand, CD44 declined from highest expression at the oocyte stage to show a second maximum at the compacted 8-cell/morula. This molecule exhibited high expression around contact areas between trophecto-derm and zona pellucida during blastocyst hatching. CD49d was highly expressed in the oocyte, remained significantly expressed throughout and after blastocyst hatching was expressed on the polar trophecto-derm. Like CD44, CD49d declined to undetectable levels at the blastocyst outgrowth stage. Expression of both 相似文献
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Daiju Morita Jong Cheol Rah John T. R. Isaac 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2014,369(1633)
Despite decades of study, the mechanisms by which synapses express the increase in strength during long-term potentiation (LTP) remain an area of intense interest. Here, we have studied how AMPA receptor subunit composition changes during the early phases of hippocampal LTP in CA1 pyramidal neurons. We studied LTP at silent synapses that initially lack AMPA receptors, but contain NMDA receptors. We show that strongly inwardly rectifying AMPA receptors are initially incorporated at silent synapses during LTP and are then subsequently replaced by non-rectifying AMPA receptors. These findings suggest that silent synapses initially incorporate GluA2-lacking, calcium-permeable AMPA receptors during LTP that are then replaced by GluA2-containing calcium-impermeable receptors. We also show that LTP consolidation at CA1 synapses requires a rise in intracellular calcium concentration during the early phase of expression, indicating that calcium influx through the GluA2-lacking AMPA receptors drives their replacement by GluA2-containing receptors during LTP consolidation. Taken together with previous studies in hippocampus and in other brain regions, these findings suggest that a common mechanism for the expression of activity-dependent glutamatergic synaptic plasticity involves the regulation of GluA2-subunit composition and highlights a critical role for silent synapses in this process. 相似文献
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Recognizing the forest for the trees: testing temporal patterns of cladogenesis using a null model of stochastic diversification 总被引:2,自引:1,他引:1
Computer simulations are developed and employed to examine the expected
temporal distributions of nodes under a null model of stochastic lineage
bifurcation and extinction. These Markovian models of phylogenetic process
were constructed so as to permit direct comparisons against empirical
phylogenetic trees generated from molecular or other information available
solely from extant species. For replicate simulated phylads with n extant
species, cumulative distribution functions (cdf's) of branching times were
calculated, and compared (using the Kolmogorov-Smirnov test statistic D) to
those from three published empirical trees. Molecular phylogenies for
columbine plants and avian cranes showed statistically significant
departures from the null expectations, in directions indicating recent and
ancient species' radiations, respectively, whereas a molecular phylogeny
for the Drosophila virilis species group showed no apparent historical
clustering of branching events. Effects of outgroup choice and phylogenetic
frame of reference were investigated for the columbines and found to have a
predictable influence on the types of conclusions to be drawn from such
analyses. To enable other investigators to statistically test for
nonrandomness in temporal cladogenetic pattern in empirical trees generated
from data on extant species, we present tables of mean cdf's and associated
probabilities under the null model for expected branching times in phylads
of varying size. The approaches developed in this report complement and
extend those of other recent methods for employing null models to assess
the statistical significance of pattern in evolutionary trees.
相似文献
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Meral E. Kızıltan Ayşegül Gündüz Rahşan Şahin 《Journal of electromyography and kinesiology》2010,20(3):508-512
Our goal was to investigate the characteristics of the auditory brainstem reflexes in patients with hemifacial spasm (HFS) and postparalytic facial syndrome (PFS).The spasm activities and responses by supraorbital and auditory stimuli were recorded from the orbicularis oculi, the posterior auricular and the mentalis muscles in 27 HFS and 21 PFS patients. The results were compared with those of 20 controls.Blink reflex (BR) was obtained by supraorbital stimulation in normal controls and on both sides of HFS and PFS patients whereas sound evoked bilateral auditory blink reflex (ABR) in 96.3%, 90.5% and 100%, respectively. Both BR and ABR showed synkinetic spread on symptomatic sides in all patients. The posterior auricular muscle response (PAMR) was observed bilaterally in 59.3%, 42.9% and 75.0% of groups, respectively. However, there was no synkinetic spread of PAMR.Since PAMR does not show synkinetic spread even in the presence of synkinetic spread of ABR and BR, we may suggest that a distal origin may be responsible of the synkinetic spread, or PAM is probably governed by a smaller nucleus in the brainstem. Thus it may be speculated that its excitability is insufficient to stimulate the ABR nucleus, whereas the reverse process is possible. 相似文献
49.
Jiwon Chang June Choi Yoon Chan Rah Myung Hoon Yoo Kyoung Ho Oh Gi Jung Im Seung Hoon Lee Soon Young Kwon Hae-Chul Park Sung Won Chae Hak Hyun Jung 《PloS one》2016,11(3)
Sodium selenite is a trace element essential for many physiological functions in the body. It is involved in various biological processes; it acts as a cofactor for antioxidant enzymes that protect against free radicals and is reported to limit metal-mediated oxidative DNA damage. In the present study, we investigated the effect of sodium selenite on neomycin ototoxicity in wild-type and transgenic zebrafish (Brn3C: EGFP). Five or six days post-fertilization, zebrafish larvae were co-exposed to 125 μM neomycin and various concentrations (10 μM, 100 μM, 250 μM, and 500 μM) of sodium selenite for 1 h. Hair cells within neuromasts of the supraorbital (SO1 and SO2), otic (O1), and occipital (OC1) lateral lines were analyzed by fluorescence microscopy (n = 10 fish per treatment). Hair cell survival was estimated as the ratio of the hair cell numbers in each group compared to those of the control group that were not exposed to neomycin. Apoptosis and hair cell damage of neuromasts were evaluated using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assay and 2-[4-(dimethylamino) styryl]-N-ethylpyridinium iodide (DASPEI) assay, respectively. Ultrastructural changes were evaluated using scanning electron microscopy and transmission electron microscopy. Neuromast hair cells were preserved in zebrafish exposed to 125 μM neomycin and 500 μM sodium selenite for 1 h. Sodium selenite protected against neomycin-induced hair cell loss of neuromasts, reduced apoptosis, and prevented zebrafish ultrastructural changes. We propose that sodium selenite protects against neomycin-induced hair cell damage by inhibiting apoptosis, decreasing the disarray of stereocilia, and preventing ultrastructural changes in the neuromast hair cells of the zebrafish. 相似文献
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