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61.
62.
E Walum 《Biochemical and biophysical research communications》1979,88(4):1271-1274
Tritiated glutamine and choline were released from human glioma cells in culture when incubated in permeant-free solution. Counter transport experiments revealed that the two neurotransmitter precursors were taken up and released by facilitated diffussion transport systems. It is suggested that glial cells can provide neurons with glutamine and choline for transmitter synthesis via such systems. 相似文献
63.
64.
This paper proposes to split the Australian Polyommatini genus Erysichton Fruhstorfer, 1916 into two genera on the basis of molecular, morphological and early stage behavioral attributes. The utility of reflective eye pattern as a taxonomic character is discussed and a neotype of Lycaena lineata Murray, 1874 is designated. 相似文献
65.
C. K. Thoeringer U. J. Pfeiffer G. Rammes F. A. Pamplona S. Moosmang C. T. Wotjak 《Genes, Brain & Behavior》2010,9(8):947-957
Environmental factors may unleash genetically determined susceptibility to psychopathology. Great effort has been spent in identifying both the genetic basis and environmental sources of exaggerated fear in animal models of anxiety disorders. Here, we show that the origin of inbred mice, probably via subtle differences in breeding and rearing conditions, may have large consequences specifically on acquisition and retention of fear memories, while leaving anxiety‐related behaviours unaffected. These effects could be seen in BALB/cAnN (BALB), but not in C57BL/6N (C57BL/6) mice, thus suggesting their dependency on the genetic background. Increased susceptibility for developing exaggerated fear responses was accompanied by decreased long‐term depression and increased surface trafficking of the AMPA receptor GluR1 subunit at the level of the basolateral amygdala complex. Together, these data raise a novel caveat in the debate about the origins of variation in behavioural studies with experimental animals. Considering that there are currently no animal models which explicitly consider conceptual analogy to the specific gene–environment interactions observed in the aetiology of phobias, our study might suggest a novel approach and direction for further preclinical studies focusing on such aspects of phobic‐like fears. 相似文献
66.
Flow cytometry is now being used more frequently to determine sperm functional characteristics during semen assessment for artificial insemination. With this methodology, viable and potentially functional cells are detected as unstained events differentiated from non-sperm events through their light-scattering characteristics. However, it can be shown mathematically that identification of sperm on the basis of light scatter leads to significant overestimation of unstained viable cells and underestimation of responding cells in tests of sperm function (subpopulations expressing different fluorescence patterns). We have developed a simple and cost-efficient flow cytometric approach for identifying non-sperm particles that can be carried out in parallel with functional assessments. Our method is based on the sperm's osmotic intolerance. Diluted in water, lethal osmotic shock causes major damage to the cell membranes, and all sperm will stain with propidium iodide (PI). Particulate material which is not PI-positive can then be quantitatively evaluated by FACS analysis and the results substituted in mathematical equations to provide true values for sperm counts and subpopulations. In practical tests, the percentage of non-sperm particles determined by this technique was closely comparable to the figure obtained either by SYBR14®/PI staining or by PI/CFDA staining. As well as being valuable with respect to tests of sperm function, the procedure is also suitable for obtaining accurate sperm counts during routine semen evaluation. 相似文献
67.
Barry M. Zee Rebecca S. Levin Bo Xu Gary LeRoy Ned S. Wingreen Benjamin A. Garcia 《The Journal of biological chemistry》2010,285(5):3341-3350
Methylation of specific histone residues is capable of both gene activation and silencing. Despite vast work on the function of methylation, most studies either present a static snapshot of methylation or fail to assign kinetic information to specific residues. Using liquid chromatography-tandem mass spectrometry on a high-resolution mass spectrometer and heavy methyl-SILAC labeling, we studied site-specific histone lysine and arginine methylation dynamics. The detection of labeled intermediates within a methylation state revealed that mono-, di-, and trimethylated residues generally have progressively slower rates of formation. Furthermore, methylations associated with active genes have faster rates than methylations associated with silent genes. Finally, the presence of both an active and silencing mark on the same peptide results in a slower rate of methylation than the presence of either mark alone. Here we show that quantitative proteomic approaches such as this can determine the dynamics of multiple methylated residues, an understudied portion of histone biology. 相似文献
68.
For this study, six seam sequences of Duckmantian age from the Ruhr Basin, western Germany, were analysed. 155 samples from drill cores were examined, including coal samples, as well as organic-rich and clastic sedimentary rocks. All samples were analysed using palynological and coal petrographical techniques. Based on published information of in situ miospores the encountered dispersed miospores were assigned to their parent plants in order to reconstruct the vegetation history. Six vegetational associations were identified using Detrended Correspondence Analyses (DCA): lepidocarpacean association I, lepidocarpacean association II, lepidocarpacean-sigillarian association, lepidocarpacean-sphenophyll association, lepidocarpacean-fern association, and the subarborescent lycopsid association.Lycospora is the most important constituent in the miospore association as in 75% of all samples the genus is represented with more than 50% relative abundance. Lepidocarpaceans such as Lepidophloios and Lepidodendron are very common among the plant fossils. Hence, arborescent lycopsids dominated the vegetation of the Ruhr Basin during the mid and late Duckmantian, forming flood plains and planar forest mires. Variations in the plant environment are reflected by greater influence of sigillarians, which were typical for swamp margins or for domed swamps, characterized by stunted vegetation. Fern-dominated environments were rare during the Duckmantian.A typical rhythmic succession shows an evolution from clastic flood plains through peat substrate planar mires, followed by a doming of the swamps and formation of ombrogenous mires. Floodplains reappeared during periods of subsidence, accompanied by a rise in water level. 相似文献
69.
Franck Debeurme Antoine Picciocchi Marie-Claire Dagher Didier Grunwald Sylvain Beaumel Franck Fieschi Marie-José Stasia 《The Journal of biological chemistry》2010,285(43):33197-33208
The X+-linked chronic granulomatous disease (X+-CGD) variants are natural mutants characterized by defective NADPH oxidase activity but with normal Nox2 expression. According to the three-dimensional model of the cytosolic Nox2 domain, most of the X+-CGD mutations are located in/or close to the FAD/NADPH binding regions. A structure/function study of this domain was conducted in X+-CGD PLB-985 cells exactly mimicking 10 human variants: T341K, C369R, G408E, G408R, P415H, P415L, Δ507QKT509-HIWAinsert, C537R, L546P, and E568K. Diaphorase activity is defective in all these mutants. NADPH oxidase assembly is normal for P415H/P415L and T341K mutants where mutation occurs in the consensus sequences of NADPH- and FAD-binding sites, respectively. This is in accordance with their buried position in the three-dimensional model of the cytosolic Nox2 domain. FAD incorporation is abolished only in the T341K mutant explaining its absence of diaphorase activity. This demonstrates that NADPH oxidase assembly can occur without FAD incorporation. In addition, a defect of NADPH binding is a plausible explanation for the diaphorase activity inhibition in the P415H, P415L, and C537R mutants. In contrast, Cys-369, Gly-408, Leu-546, and Glu-568 are essential for NADPH oxidase complex assembly. However, according to their position in the three-dimensional model of the cytosolic domain of Nox2, only Cys-369 could be in direct contact with cytosolic factors during oxidase assembly. In addition, the defect in oxidase assembly observed in the C369R, G408E, G408R, and E568K mutants correlates with the lack of FAD incorporation. Thus, the NADPH oxidase assembly process and FAD incorporation are closely related events essential for the diaphorase activity of Nox2. 相似文献
70.
Hendrik Verschueren 《Cell biology and toxicology》1985,1(3):145-157
In vitro directional migration of 10 T1/2 fibroblasts is partially inhibited by TPA but not by its non promoting analogues. Other tumor promoters, e.g., phenobarbital, saccharin, and benzoylperoxide had no measurable effect when added in concentrations known to affect in vitro two-step transformation or intercellular communication. Inhibitors of in vitro transformation do not affect migration, except for dexamethasone, which inhibited it. Hence, there is no evidence for a general correlation between tumor promoting potential and inhibition of in vitro directional migration.Abbreviations DDT
1,1,1-trichloro-2,2-bis(p-cholorophenyl) ethane
- DEXA
dexamethasone
- DMSO
dimethylsulfoxide
- RA
retinylacetate
- SD
standard deviation
- SOD
superoxide dismutase
- TPA
12-0-tetradecanoylphorbol-13-acetate; 4-0-Me-TPA, 4-0-methyl-TPA 相似文献