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991.
Davar Khodadadi Reza Gharakhanlou Naser Naghdi Mona Salimi Mohammad Azimi Atabak Shahed Soomaayeh Heysieattalab 《Neurochemical research》2018,43(8):1561-1574
Aggregated amyloid beta (Aβ) peptides are believed to play a decisive role in the pathology of Alzheimer’s disease (AD). Previous evidence suggested that exercise contributes to the improvement of cognitive decline and slows down pathogenesis of AD; however, the exact mechanisms for this have not been fully understood. Here, we evaluated the effect of a 4-week moderate treadmill exercise on spatial memory via central and peripheral Aβ clearance mechanisms following developed AD-like neuropathology induced by intra-hippocampal Aβ1–42 injection in male Wistar rats. We found Aβ1–42-treated animals showed spatial learning and memory impairment which was accompanied by increased levels of amyloid plaque load and soluble Aβ1–42 (sAβ1–42), decreased mRNA and protein expression of neprilysin (NEP), insulin degrading enzyme (IDE) and low-density lipoprotein receptor-related protein-1 (LRP-1) in the hippocampus. Aβ1–42-treated animals also exhibited a higher level of sAβ1–42 and a lower level of soluble LRP-1 (sLRP-1) in plasma, as well as a decreased level of LRP-1 mRNA and protein content in the liver. However, exercise training improved the spatial learning and memory deficits, reduced both plaque load and sAβ1–42 levels, and up-regulated expression of NEP, IDE, and LRP-1 in the hippocampus of Aβ1–42-treated animals. Aβ1–42-treated animals subjected to treadmill exercise also revealed decreased levels of sAβ1–42 and increased levels of sLRP-1 in plasma, as well as increased levels of LRP-1 mRNA and protein in the liver. In conclusion, our findings suggest that exercise-induced improvement in both of central and peripheral Aβ clearance are likely involved in ameliorating spatial learning and memory deficits in an animal model of AD. Future studies need to determine their relative contribution. 相似文献
992.
Vazken M. Der Kaloustian Rola Masri Adele Khudr Fayrouz Talj Bisharah Libbus Mona Nabulsi Farid P. Khouri 《Human genetics》1987,75(1):97-97
Summary This is the first report in the literature of siblings affected with Down syndrome; one sibling had a nondisjunction of chromosome 21 and the other a (21q;21q) translocation. 相似文献
993.
Nutrient-sufficient cultures of a Trondheimsfjord (Norway) cloneof the marine centric diatom Skeleionema costatum (Grev.) Clevewere grown at 75 µmol m2 s1 and 15C at24 and 12 h daylength to study diurnal variations and the effectof daylength on pigment and chemical composition, photosyntheticparameters, dark respiration rates and scaled fluorescence excitationspectra (F), the latter used as estimates for the absorptionof energy available to Photosystem II. Specific growth rateswere 1.06 and 0.56 day in 24 and 12 h daylength, respectively,while dark respiration rates were generally 85% of the net growthrate. The Chla-normalized photosynthetic coefficients PBm andaB were {small tilde}2025% higher in continuous lightthan at 12 h daylength, while the Chla:C ratio was {small tilde}15%lower (0.051 versus 0.061 w:w). Thus, the carbon-normalizedcoefficients Pcm and ac were <11% lower at 24 h than at 12h daylength. The maximum quantum yield max, the Chla:C ratioand F differed negligibly, as did the light saturation indexlk, the N:C ratio and the ratios Chlc:Chla and Fucoxanthin:Chla. PBm and lk did not exhibit diurnal variations at 24 hdaylength, and varied within 23% of the daily mean at 12 h daylength.Predictions of the daily gross photosynthetic rate based ondata for a given time of the day should thus not be >10%in error relative to an integrated value based on several datasets collected through 24 h. max was 0.0840.117 mol O2(mol photons) for gross oxygen evolution. However, ifused in mathematical models for predicting the gross and netgrowth rates (i.e. the gross and net carbon turnover rates),practical values of 0.076 and 0.040 g-at C (molphotons), respectively, should be employed. Correspondingly,values for aB and PBm should be adjusted pro rata.
1Present address: College of Marine Studies, Sjmannsveien 27,N-6008 lesund, Norway 相似文献
994.
Damage to Neurons in Culture Following Medium Change: Role of Glutamine and Extracellular Generation of Glutamate 总被引:3,自引:0,他引:3
Bernard F. Driscoll Gladys E. Deibler Mona J. Law Alison M. Crane 《Journal of neurochemistry》1993,61(5):1795-1800
Abstract— Changing the medium of primary cell cultures of CNS origin causes severe damage that is mediated via the N -methyl- d -aspartate (NMDA)-type of glutamate receptors and dependent on the presence of glutamine in the medium. Data presented here show that glutamine has two roles in culture damage: glutamine is contaminated with a small amount of glutamate, which is responsible for initiating culture damage, and glutamine is the source of the glutamate that is produced extracellularly in damaged cultures. The NMDA receptor plays a critical role minutes after medium change when the glutamate contaminating the glutamine binds to NMDA receptors; during this time, addition of a low level (10–20 μ M ) of 2-amino-5-phos-phonovaleric acid can block most culture damage and the appearance of extracellular glutamate. A higher level (300 μ M ) of 2-amino-5-phosphonovaleric acid can protect cultures when added at much later times (30–60 min). Between 3 and 6 h after medium change, the concentration of extracellular glutamate starts to rise and accumulates until the end of the culture period (20 h). Medium removed from cultures at 3 h or later after medium change and incubated alone (i.e., with no cells) also continues to generate glutamate; filtration (0.22 μrn pore size) or centrifugation (18,000 g) stops the appearance of this glutamate. 6-Diazo-5-oxo- l -norleucine, an inhibitor of the mitochondrial enzyme glutaminase, blocks the generation of glutamate. Mitochondria or mitochondrial fragments are probably released from the damaged cells and then convert extracellular glutamine to glutamate, resulting in generation of a high extracellular glutamate concentration. 相似文献
995.
Eva Agurell Hakan Cederberg Mona Hedenskog Ulf Rannug 《Molecular & general genetics : MGG》1994,242(2):137-144
To study chemically induced DNA amplifications we used the haploid Saccharomyces cerevisiae strain TR(MS1)-1 carrying an integrated chromosomal copy of the human minisatellite, MS1. Chemicals with different mechanisms of action were tested in this strain: methyl methanesulphonate, ethylene oxide (EO), propylene oxide (PO), camptothecin, 2,3,7,8-tetrachlorodibenso-p-dioxin (TCDD) and reserpine. No increase in frequency of new MS1 length alleles was seen with any of the tested chemicals relative to the spontaneous frequency of approximately 30%. EO and TCDD induced changes in the amplification spectrum, i.e. the frequency distribution of MS1 length alleles longer than the original 1.42 kb allele. PO and camptothecin increased the frequency of plasmid pop-out events. It seems likely that several mechanisms e.g. unequal exchanges, replication slippage and loop formation leading to deletion of a ring of tandem repeats, are involved in the generation of new MS1 length alleles. A loop-forming deletion mechanism is supported by the tendency to multimodality shown in the deamplification (loss of repeat units) spectra, i.e. the frequency distribution of new MS1 length alleles shorter than the original allele. EO and TCDD induced longer MS1 length alleles as compared to the control. The frequent generation of new MS1 length alleles in this haploid yeast strain further demonstrates the instability of such sequences and their possible relevance to genetic toxicology and the mechanisms of induction of cancer as well as other diseases. This study is a first step towards the development of an assay for DNA amplification without the use of a selective agent. 相似文献
996.
The complete primary structure of the coat protein of strain VRU of alfalfa mosaic virus (AMV) is reported. The strain is morphologically different from all other AMV strains as it contains large amounts of unusually long virus particles. This is caused by structural differences in the coat protein chain. The amino acid sequence has mainly been established by the characterization of peptides obtained after cleavage with cyanogen bromide and digestion with trypsin, chymotrypsin, thermolysin or Staphylococcus aureus protease. The major sequencing technique used was the dansyl-Edman procedure. The VRU coat protein consists of 219 amino acid residues corresponding to a molecular weight of 24056. Compared to the coat protein of strain 425 [Van Beynum et al. (1977) Eur. J. Biochem. 72, 63-78], 15 amino acid substitutions were localized. Most of them have a conservative character and may be explained by single-point mutations. A correction is given for the AMV 425 coat protein: Asn-216 was shown to be Asp-216. The prediction of the secondary structure for the two viral coat proteins was not significantly influenced by the various amino acid substitutions except for the region containing residues 65-100. This led us to the hypothesis that the AMV coat protein may occur in two different conformations favouring its incorporation into either a pentagonal or hexagonal quasi-equivalent position in the lattice of the protein shell. The substitutions in the above-mentioned region of the VRU coat protein may have caused a strong preference for the hexagonal lattice conformation. The model is supported by preliminary sequence data of the same coat protein region in AMV 15/64, a strain morphologically intermediate between 425 and VRU. 相似文献
997.
William A. Miller Mona M. Everett John T. Freedman W. Christopher Feagans Jeffrey F. Cramer 《In vitro cellular & developmental biology. Plant》1976,12(8):580-588
Summary Effects of the enzymes trypsin, papain, bromelains and ficin in bovine dental pulp tissue were studied. Minced or whole pulps
were subjected to each enzyme at 17°, 20° and 37°C for set time intervals, after which aliquots of supernatant fluid were
removed for cell counts and viability tests. Pooled samples were subsequently cultured as monolayers in Eagle’s MEM plus 10%
calf serum. The dissociation characteristics were quite distinct for each enzyme, although quite similar between minced and
whole pulp. A parallel histological study was made of the residual pulp tissue. Ficin was found to be the most suitable enzyme
for future studies on the growth of isolated pulp cells from various layers of the bovine pulp, due to its even rate of cell
removal, and the good initial viability and subsequent growth of the separated cells in monolayer culture. Further studies
on ficin may show that it is more suitable for enzymatic separation of tissues generally than the more commonly used trypsin,
a major advantage being its use in media containing Ca2+ and Mg2+.
Supported in part by NIH Grant No. DE 02908 and by United Health Foundation Summer Fellowships to J.T.F. and J.F.C.
Supported in part by N.I.H. Grant 5 R01-DE 02908 to W.A.M. and by United Health Foundation Summer Fellowships to J.T.F. and
J.F.C. 相似文献
998.
999.
Mohamad El Amki Martine Dubois Antoine Lefevre-Scelles Nicolas Magne Mélanie Roussel Thomas Clavier Pierre-Olivier Guichet Emmanuel Gérardin Vincent Compère Hélène Castel 《Molecular neurobiology》2018,55(4):2763-2779
Subarachnoid hemorrhage (SAH) is a devastating disease with high mortality and morbidity. Long-term cognitive and sensorimotor deficits are serious complications following SAH but still not well explained and described in mouse preclinical models. The aim of our study is to characterize a well-mastered SAH murine model and to establish developing pathological mechanisms leading to cognitive and motor deficits, allowing identification of specific targets involved in these long-term troubles. We hereby demonstrate that the double blood injection model of SAH induced long-lasting large cerebral artery vasospasm (CVS), microthrombosis formation and cerebral brain damage including defect in potential paravascular diffusion. These neurobiological alterations appear to be associated with sensorimotor and cognitive dysfunctions mainly detected 10 days after the bleeding episode. In conclusion, this characterized model of SAH in mice, stressing prolonged neurobiological pathological mechanisms and associated sensitivomotor deficits, will constitute a validated preclinical model to better decipher the link between CVS, long-term cerebral apoptosis and cognitive disorders occurring during SAH and to allow investigating novel therapeutic approaches in transgenic mice. 相似文献
1000.