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1.
Meredith  Michael 《Chemical senses》1981,6(4):277-293
The response of goldfish olfactory bulb neurons to a range ofamino acid olfactory stimuli was recorded. The results showthat comparisons of response patterns at a single concentrationare inadequate to describe the similarity of response of thesystem to pairs of substances because response patterns changedwith concentration. For some pairs of stimuli, the similaritybetween response patterns was consistent at different concentrationsdespite the changes seen in the responses themselves. In thesecases the similarity of response appeared to reflect the degreeof similarity in chemical structure of the stimuli. Preliminaryevidence is presented that differences in response to differentamino acids are not simply due to differences in stimulatoryeffectiveness for a single receptor process.  相似文献   

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Misumi K  Suzuki M  Sato S  Saito N 《Theriogenology》2003,60(2):253-260
This study was conducted to determine the efficiency of vitrification using the microdroplet (MD) method for early stage porcine embryos. Embryos at compacted morulae to early blastocyst stage were vitrified in a vitrification solution containing 40% (v/v) ethylene glycol, 0.6M sucrose and 2% (w/v) polyethylene glycol in M2 (ESP) without any pretreatment. The equilibration and dilution were carried out in third and fourth steps, respectively, at 38 degrees C. The survivability of the cryopreserved embryos was assessed for both in vitro culture (Experiment 1) and by embryo transfer (Experiment 2). In Experiment 1, the embryos were vitrified within a microdroplet or 0.25 ml straw (ST) and fresh embryos were used as a control group. The survival rates after 24h culture in the MD, ST and control groups were 21/23, 14/20 and 20/20, respectively. The hatching rates of the embryos after 48 h incubation were 14/23, 4/20 and 16/20, respectively. In Experiment 2, 171 vitrified embryos were transferred to 5 recipient gilts, and 17 healthy piglets were produced from 2 recipients (3 recipients aborted) in Group 1. In Group 2, 81 vitrified embryos and 16 fresh embryos in total were transferred to 4 recipient gilts, and 10 healthy piglets from the vitrified embryos were produced from 3 recipients. These results indicated that porcine embryos of compacted morulae to early blastocyst stage can survive cryopreservation using the microdroplet method without any special intracellular manipulation or treatment.  相似文献   

5.
Li  Daoyuan  Lin  Feifei  Li  Guoping  Zeng  Fanchang 《Cytotechnology》2021,73(4):593-604

Exosomes derived from mesenchymal stem cells (MSC-Exo) are effective in modulating immunity. However, the role of MSC-Exo in clear cell renal cell carcinoma (ccRCC) is unclear. Our study was performed to identify if exosomal microRNA (miRNA) can be used as potential noninvasive biomarkers for ccRCC therapy. An orthotopic ccRCC mouse model was established, followed by MSC-Exo injection (1 mL, 20 μg/mL). The metastases of tumors were observed using HE staining, while number of dendritic cells, natural killing (NK) T cells and CD8+ T cells was measured using flow cytometry. It was observed that MSC-Exo treatment significantly inhibited metastasis and growth of tumors, and improved immune response in vivo. As for in vitro assay, naive T cells were treated with MSC-Exo, followed by detection of T cell proliferation using EdU staining and CFSE assay. Results also showed that MSC-Exo facilitated sensitivity of ccRCC cells to NK T cells. Our experimental data further showed that miR-182 could be delivered by MSC-Exo in ccRCC, which targeted vascular endothelial growth factor A (VEGFA), as dual-luciferase reporter assays validated. In conclusion, miR-182 contained in MSC-Exo promoted immune response of T cells by suppressing VEGFA expression, thus alleviating ccRCC development.

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To better understand the immediate early genetic response of myeloid cells to terminal differentiation and growth inhibitory stimuli, complementary DNA clones of myeloid differentiation primary response (MyD) genes have recently been isolated. In this study, a set of known (junB, c-jun, ICAM-1, H1(0), and H3.3 histone variants) and novel (MyD88, MyD116) MyD genes were used as immediate early molecular markers to further dissect the primary genetic response of myeloid cells to various differentiation and growth inhibitory stimuli. Expression of all of these MyD genes was highly induced in autonomously replicating differentiation inducible M1D+ myeloblasts following induction of terminal differentiation and growth inhibition by interleukin 6. Expression of all MyD genes except MyD88 was induced upon inhibition of M1D+ cell growth and induction of early, but not late, differentiation markers by interleukin 1 and lipopolysaccharide. In sharp contrast, only expression of H1(0) and H3.3 histone variants was increased following inhibition of M1D+ cell growth by interferon beta or gamma, which did not induce any differentiation associated properties. No increase in the expression of any of these MyD genes was seen in a clone of WEHI-3B D- myelomonocytic cells following stimulation with interleukin 6, which neither induced it for differentiation nor inhibited its growth. 12-O-Tetradecanoylphorbol-13-acetate, known to be a potent inducer of jun expression in many cell types, failed to induce high or stable expression of junB and c-jun in M1D+ cells, where it did not induce differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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Small RNAs derived from repetitive sequences appear to play essential roles in mammalian gametogenesis and early development. In this study we focused on the short interspersed nucleotide element B1 (SINE/B1) small RNAs, which were zygotically expressed in pre-implantation mouse embryos; and we investigated whether the SINE/B1 small RNAs played an active role in gene silencing during early mouse development. The results indicated that the level of silencing activity involving the SINE/B1 small RNAs as mediators was significantly reduced in Dicer-knockdown mouse embryos. In addition, when the SINE/B1 small RNAs were mapped to a full-length SINE/B1 sequence, phase-distribution of the small RNAs appeared, suggesting possible enzymatic involvement. Therefore, our present study suggested that the zygotically expressed SINE/B1 small RNAs in pre-implantation mouse embryos contain active small RNAs, which were presumably processed by Dicer and involved in gene silencing.  相似文献   

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Reconstruction of past climate change and ecosystem response is important to correctly assess the impacts of global warming. In this study, we provide a paleoenvironmental record of in-lake and catchment changes in northern Poland during the Late Glacial and early Holocene using various biotic proxies (pollen, macrofossils and Cladocera) preserved in the lake sedimentary record. Chronology was derived from palynological correlation with a well-dated pollen sequence from nearby-lying Lake Ostrowite and some well-dated events of vegetation history in Central Europe. Pollen analysis provided information on regional climate change affecting vegetation dynamics, whereas macrofossils supplied substantial information on the response of local flora and fauna to climatic, geomorphological and limnological changes. Data were supplemented by analysis of Cladocera remains, which are of special importance because of their quick response to changes in trophic conditions and climate (especially temperature). The bottom of the sediment core reflects an initial stage of the lake formed during the late Aller?d. The Younger Dryas cooling apparently resulted in forest recession and presence of cold tolerant Cladocera species. Due to amelioration of climate at the end of the Younger Dryas and melting of ice, the lake deepened. The beginning of the Holocene was characterised by forest shrinkage and induced clear changes in local flora and fauna communities. The regional vegetation development deduced from the lake’s core is generally consistent with the vegetation history of central Europe. Due to the location of the site near the seashore (oceanic climate and western wind), signals of warming came earlier than inland and in eastern Poland.  相似文献   

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The action of hexamethonium, D-tubocurarine, phentolamine, and atropine on synaptic transmission in the superior cervical ganglion was studied in the early stage of postnatal development (1–8 days after birth) and in the adult period in cats, rabbits, and rats. Hexamethonium and D-tubocurarine, if injected intravenously or added to the Krebs' solution surrounding the ganglion, were shown to inhibit the conduction of excitation through the ganglion effectively in both newborn and adult animals. No significant difference in the action of phentolamine and atropine on synaptic transmission in the ganglia could be found in these groups of animals. It is concluded that synaptic transmission in sympathetic ganglia is cholinergic in the early stage of postnatal development of animals blind at birth.  相似文献   

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Preterm birth is a strong contributor to perinatal mortality, and preterm infants that survive are at risk for long-term morbidities. During most of pregnancy, appropriate mechanical function of the cervix is required to maintain the developing fetus in utero. Premature cervical softening and subsequent cervical shortening are hypothesized to cause preterm birth. Presently, there is a lack of understanding of the structural and material factors that influence the mechanical function of the cervix during pregnancy. In this study we build finite element models of the pregnant uterus, cervix, and fetal membrane based on magnetic resonance imagining data in order to examine the mechanical function of the cervix under the physiologic loading conditions of pregnancy. We calculate the mechanical loading state of the cervix for two pregnant patients: 22 weeks gestational age with a normal cervical length and 28 weeks with a short cervix. We investigate the influence of (1) anatomical geometry, (2) cervical material properties, and (3) fetal membrane material properties, including its adhesion properties, on the mechanical loading state of the cervix under physiologically relevant intrauterine pressures. Our study demonstrates that membrane–uterus interaction, cervical material modeling, and membrane mechanical properties are factors that must be deliberately and carefully handled in order to construct a high quality mechanical simulation of pregnancy.  相似文献   

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This study aimed to determine the effect of extremely low‐frequency electromagnetic fields (ELF‐EMF) on the physiological response of phagocytes to an infectious agent. THP‐1 cells (human monocytic leukemia cell line) were cultured and 50 Hz, 1 mT EMF was applied for 4–6 h to cells induced with Staphylococcus aureus or interferon gamma/lipopolysaccharide (IFγ/LPS). Alterations in nitric oxide (NO), inducible nitric oxide synthase (iNOS) levels, heat shock protein 70 levels (hsp70), cGMP levels, caspase‐9 activation, and the growth rate of S. aureus were determined. The growth curve of exposed bacteria was lower than the control. Field application increased NO levels. The increase was more prominent for S. aureus‐induced cells and appeared earlier than the increase in cells without field application. However, a slight decrease was observed in iNOS levels. Increased cGMP levels in response to field application were closely correlated with increased NO levels. ELF‐EMF alone caused increased hsp70 levels in a time‐dependent manner. When cells were induced with S. aureus or IFγ/LPS, field application produced higher levels of hsp70. ELF‐EMF suppressed caspase‐9 activation by a small extent. These data confirm that ELF‐EMF affects bacterial growth and the response of the immune system to bacterial challenges, suggesting that ELF‐EMF could be exploited for beneficial uses. Bioelectromagnetics 31:603–612, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

12.
The three-dimensional potential flow field around a moving fish with an axially symmetric body is investigated mathematically. The case of a moving fish in open water and that of one approaching a plane surface in front of it are considered. For these cases the spatial and temporal distributions of the stimuli to the lateral line system are derived from the flow field analysis. This is done in dependence on the shape and the size of the fish.  相似文献   

13.
The first wave of myoblasts which constitutes the post-mitotic myotome stems from the medial epithelial somite. Whereas medial pioneers extend throughout the entire mediolateral myotome at cervical and limb levels, at flank regions they are complemented laterally by a population of early myoblasts emerging from the lateral epithelial somite. These myoblasts delaminate underneath the nascent dermomyotome and become post-mitotic. They are Myf5-positive but express MyoD and desmin only a day later while differentiating into fibers. Overexpression of Noggin in the lateral somite triggers their premature differentiation suggesting that lateral plate-BMP4 maintains them in an undifferentiated state. Moreover, directly accelerating their differentiation by MyoD overexpression prior to arrival of medial fibers, generates a severely mispatterned lateral myotome. This is in contrast to medial pioneers that have the capacity for self-organization. Furthermore, inhibiting differentiation of medial pioneers with dominant-negative MyoD also disrupts lateral myoblast patterning and differentiation. Thus, we propose that medial pioneers are needed for proper morphogenesis of the lateral population which is kept as undifferentiated mesenchyme by BMP4 until their arrival. In addition, medial pioneers also organize dermomyotome lip-derived fibers suggesting that they have a general role in patterning myotome development.  相似文献   

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Summary In mice (strain NMRI) the influence of olfactory rearing conditions on the ontogenetic development of the bulbar electroencephalogram (EEG) was investigated.The cages of control animals were perfused continually with filtered air, whereas in the three experimental groups geraniol was added to the atmosphere at different times (group G0–13, from birth till day 13; group G0–6, from birth till day 6; group G6–12, from day 6 till day 12). At various ages the EEG of the bulbus olfactorius was studied by means of permanently implanted tungsten electrodes, and the neural response to nest odour and geraniol (10–2 vol. %) was recorded.No differences were found between the groups regarding the overall development of the bulbar EEG, nor did the raising conditions affect the neural response to nest odour. However, in groups G0–13 and G6–12 a marked response to the odour of geraniol was recorded, while in the controls and the individuals that had experienced geraniol only during their first week of life, the bulbar response to this odourant did not differ from that obtained following stimulation with clean air. In the animals of group g0–13, which were investigated as adults (day 70), the prominent geraniol response was still recordable 2 months after the last contact with the odour.These results indicate that odours experienced during a sensitive period in the nest evoke neuronal alterations in the olfactory system of the mouse that facilitate processing of a known odourant.  相似文献   

16.
The ability to synthesize a 68,000- to 70,000-Da protein (hsp) in heat-shocked early Xenopus laevis embryos is dependent on the stage of development. Whereas late blastula and later stage embryos synthesize hsp68-70 after heat shock, cleavage stages are incompetent with respect to hsp synthesis. In vitro translation experiments and RNA blot analyses demonstrate that enhanced synthesis of hsp68-70 is associated with an accumulation of hsp68-70 mRNA. Examination of the effect of heat shock on preexisting actin mRNA reveals that heat shock promotes a reduction in the levels of actin mRNA in cleavage embryos but has no discernible effect on actin mRNA levels in neurula embryos. Finally, the acquisition of the heat-shock response (i.e., synthesis of hsp68-70 and accumulation of hsp70 mRNA) during early Xenopus development is correlated with the acquisition of thermotolerance.  相似文献   

17.
Liver preparations from turpentine-treated rats show an increased capacity to autophosphorylate a protein of 32.5 kDa (p 32.5): both the kinase and the substrate protein are strongly bound to the membrane fraction, but the protein is released to the cytosol after phosphorylation, which occurs exclusively in serine residues. No known second messenger-dependent protein kinase seems to be responsible for the reaction. Phosphorylation of p 32.5 could be an early post-receptorial event after turpentine-treatment possibly caused by cytokines and involved in the pathogenesis of further events of the acute-phase response.  相似文献   

18.
We aimed to investigate the potential beneficial effect of ferulic acid (FA) on stemness of human tendon‐derived stem cells (hTSCs) in vitro and to elucidate the underlying molecular mechanism. The self‐renewal ability of hTSCs was evaluated by colony formation and cell proliferation was determined by CCK‐8 kit. Adipogenesis, osteogenesis, and chondrogenesis were determined by Oil Red O, Alizarin Red, and Alcian Blue stainings, respectively. Relative mRNA levels of PPARγ, Col2A1, Acan, Runx2, HIF1α, and EGR1 were measured with real‐time PCR. Protein levels of HIF1α and EGR1 were detected by western blot. Direct binding of HIF1α with EGR1 promoter was analyzed by ChIP assay. Hypoxia‐induced expression of EGR1 was interrogated by luciferase reporter assay. We demonstrated that FA treatment improved both self‐renewal ability and multi‐differentiation potential of hTSCs. FA induced hypoxia which in turn upregulated EGR1 expression via direct association with its hypoxia response element consensus sequence. Furthermore, we showed that both HIF1α and EGR1 were required for the enhancing effects of FA on hTSC self‐renewal and differentiation. We hereby characterize the beneficial effect of FA on the stemness of hTSCs and highlight the critical role of HIF1α‐EGR1 axis in this process.  相似文献   

19.
It has been shown that from the group of three restriction endonucleases (XbaI, Uba 78I, DraI) only XbaI digests the native Pseudomonas genomic DNA into the number of fragments, sufficient for their comparative analysis. Optimal electrophoresis conditions were adjusted for the better DNA restricts separation. Each Pseudomonas culture gives unique patterns of DNA restriction. The calculation of the conservative fragments fraction content in the samples led us to the conclusion that P. fluorescens differs equally from both P. fluorescens 80 and P. alcaligenes. The P. fluorescens 80 DNA contains a relatively larger number of fragments equal in size with those of P. alcaligenes DNA, than DNA of P. fluorescens. We have concluded that the systematics of the Pseudomonas genus is still imperfect and that the analysis of DNA restriction patterns is necessary for the estimation of the similarity level of cultures studied.  相似文献   

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