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101.
鸡胚早期神经系统发育中凋亡细胞的分布研究 总被引:2,自引:0,他引:2
研究鸡胚18S(Stage)神经系统发育中凋亡细胞的分布及其生物学意义。采用HNK-1和TUNEL免疫组化双染及改变切片方向的方法观察了神经管和神经嵴的凋亡细胞,结果显示:凋亡的细胞在间隔10张横向切片上呈非均匀分布,但在矢状切面凋亡细胞有节段性分布趋势。体节处连续神经嵴没有发现凋亡细胞,而体节与体节之间神经嵴迁离神经管呈游离状并有凋亡细胞,神经管腹侧面体节处间充质细胞呈现细胞凋亡节段性分布。结果表明:鸡胚早期神经系统发育中选择性发生细胞凋亡作用。 相似文献
102.
Inert gas narcotics increase intrinsic pressure tolerance (1,000Pc) in CD-1 mice but interfere with development of the protective responses raising seizure thresholds during slower compression (e.g., 60Pc). This secondary narcotic effect can block up to 40% of the total attainable increase in Pc. The narcosis susceptible moiety of this compression rate effect develops early, whereas a narcosis resistant remnant accounts for increase in Pc occurring after 90 min of compression or pressure exposure. Pressure conditioning by multiday pressure exposure entails increases in both 60Pc and 1,000Pc and in virtual annullment of the compression rate effect. The effect can be completely blocked by narcotic gases in the conditioning atmosphere. In addition to blocking part of the compression rate effect the presence of narcotic gases under these conditions can reverse the effects of previously established pressure conditioning. 60Pc regresses much more slowly under these conditions than 1,000Pc. Either reversal rate is much more rapid in air at 1 ATA than at 80 ATA under 0.9 atm N2O. The implications of these data are discussed with regard to evaluation of the hypothesis of antagonism between inert gas narcotics and high pressures and to elaboration of the monoamine hypothesis to account for the modification of the compression rate effect by narcotic gases. 相似文献
103.
104.
Single cell profiling was performed to assess differences in RNA accumulation in neighboring hyphae of the fungus Aspergillus niger. A protocol was developed to isolate and amplify RNA from single hyphae or parts thereof. Microarray analysis resulted in
a present call for 4 to 7% of the A. niger genes, of which 12% showed heterogeneous RNA levels. These genes belonged to a wide range of gene categories. 相似文献
105.
Edith HC Cup Astrid Kinébanian Ton Satink Allan J Pieterse Henk T Hendricks Rob AB Oostendorp Gert Jan van der Wilt Baziel GM van Engelen 《BMC neurology》2011,11(1):86
Background
Myotonic dystrophy type 1 (MD1) is one of the most prevalent neuromuscular diseases, yet very little is known about how MD1 affects the lives of couples and how they themselves manage individually and together. To better match health care to their problems, concerns and needs, it is important to understand their perspective of living with this hereditary, systemic disease. 相似文献106.
Björn Peters Anja Junker Katharina Brauer Bernadette Mühlthaler David Kostner Markus Mientus Wolfgang Liebl Armin Ehrenreich 《Applied microbiology and biotechnology》2013,97(6):2521-2530
Gluconobacter oxydans, a biotechnologically relevant species which incompletely oxidizes a large variety of carbohydrates, alcohols, and related compounds, contains a gene for pyruvate decarboxylase (PDC). This enzyme is found only in very few species of bacteria where it is normally involved in anaerobic ethanol formation via acetaldehyde. In order to clarify the role of PDC in the strictly oxidative metabolism of acetic acid bacteria, we developed a markerless in-frame deletion system for strain G. oxydans 621H which uses 5-fluorouracil together with a plasmid-encoded uracil phosphoribosyltransferase as counter selection method and used this technique to delete the PDC gene (GOX1081) of G. oxydans 621H. The PDC deletion mutant accumulated large amounts of pyruvate but almost no acetate during growth on d-mannitol, d-fructose or in the presence of l-lactate. This suggested that in G. oxydans acetate formation occurs by decarboxylation of pyruvate and subsequent oxidation of acetaldehyde to acetate. This observation and the efficiency of the markerless deletion system were confirmed by constructing deletion mutants of two acetaldehyde dehydrogenases (GOX1122 and GOX2018) and of the acetyl-CoA-synthetase (GOX0412). Acetate formation during growth of these mutants on mannitol did not differ significantly from the wild-type strain. 相似文献
107.
Torres JZ Summers MK Peterson D Brauer MJ Lee J Senese S Gholkar AA Lo YC Lei X Jung K Anderson DC Davis DP Belmont L Jackson PK 《Cell》2011,147(6):1309-1323
During cell division, cells form the microtubule-based mitotic spindle, a highly specialized and dynamic structure that mediates proper chromosome transmission to daughter cells. Cancer cells can show perturbed mitotic spindles and an approach in cancer treatment has been to trigger cell killing by targeting microtubule dynamics or spindle assembly. To identify and characterize proteins necessary for spindle assembly, and potential antimitotic targets, we performed a proteomic and genetic analysis of 592 mitotic microtubule copurifying proteins (MMCPs). Screening for regulators that affect both mitosis and apoptosis, we report the identification and characterization of STARD9, a kinesin-3 family member, which localizes to centrosomes and stabilizes the pericentriolar material (PCM). STARD9-depleted cells have fragmented PCM, form multipolar spindles, activate the spindle assembly checkpoint (SAC), arrest in mitosis, and undergo apoptosis. Interestingly, STARD9-depletion synergizes with the chemotherapeutic agent taxol to increase mitotic death, demonstrating that STARD9 is a mitotic kinesin and a potential antimitotic target. 相似文献
108.
Philip E. Pfeffer Yair Shachar-Hill Shu-I. Tu David Brauer 《Physiologia plantarum》2004,122(3):373-379
Methods for the simultaneous measurement of vacuolar and cytoplasmic pH in plant tissues currently have significant limitations. This study demonstrates the usefulness of methyl difluoro alanine (F2 ALA) and methyl trifluoro alanine (F3 ALA) with in-vivo 19 F NMR spectroscopy to measure vacuolar and cytoplasmic pH in maize root tissue. The pH dependence of the chemical shift of F2 ALA and F3 ALA is greater than either the commonly used 31 P NMR signal of inorganic phosphate or the 13 C NMR signals of trans-aconitic acid, which is also found in some plant cells. F2 ALA and F3 ALA were also able to detect changes over a greater range of pH. When maize root tissue was incubated in the presence of 0.35 m m F2 ALA or F3 ALA, these accumulated to significant concentrations in two compartments of different pH with no significant effect on growth rate of root tips. The time course of accumulation and the pH of the two compartments were consistent with one being the cytoplasm and the other the vacuole. The chemical shift of both C2 of trans-aconitic acid and vacuolar F3 ALA indicated that the mean vacuolar pH of maize root cells was 4.6 and that the pH gradient across the tonoplast membrane was about 2.8 units. Under a variety of conditions, there was considerable heterogeneity in the pH of the vacuoles in maize root tissue as indicated by the peak width of the signal from F3 ALA. The significance of these values is discussed in terms of the bioenergetics of proton transport across the tonoplast membrane in vivo. 相似文献
109.
Förster C Brauer AB Fürste JP Betzel Ch Weber M Cordes F Erdmann VA 《Biochemical and biophysical research communications》2007,362(2):415-418
Aminoacyl-tRNA synthetases catalyze the formation of aminoacyl-tRNAs. Seryl-tRNA synthetase is a class II synthetase, which depends on rather few and simple identity elements in tRNA(Ser) to determine the amino acid specificity. tRNA(Ser) acceptor stem microhelices can be aminoacylated with serine, which makes this part of the tRNA a valuable tool for investigating the structural motifs in a tRNA(Ser)-seryl-tRNA synthetase complex. A 1.8A-resolution tRNA(Ser) acceptor stem crystal structure was superimposed to a 2.9A-resolution crystal structure of a tRNA(Ser)-seryl-tRNA synthetase complex for a visualization of the binding environment of the tRNA(Ser) microhelix. 相似文献
110.
Mi-Sun Kim Jichan Jang Nurlilah Binte AB Rahman Kevin Pethe Edward A. Berry Li-Shar Huang 《The Journal of biological chemistry》2015,290(23):14350-14360
Recently, energy production pathways have been shown to be viable antitubercular drug targets to combat multidrug-resistant tuberculosis and eliminate pathogen in the dormant state. One family of drugs currently under development, the imidazo[1,2-a]pyridine derivatives, is believed to target the pathogen''s homolog of the mitochondrial bc1 complex. This complex, denoted cytochrome bcc, is highly divergent from mitochondrial Complex III both in subunit structure and inhibitor sensitivity, making it a good target for drug development. There is no soluble cytochrome c in mycobacteria to transport electrons from the bcc complex to cytochrome oxidase. Instead, the bcc complex exists in a “supercomplex” with a cytochrome aa3-type cytochrome oxidase, presumably allowing direct electron transfer. We describe here purification and initial characterization of the mycobacterial cytochrome bcc-aa3 supercomplex using a strain of M. smegmatis that has been engineered to express the M. tuberculosis cytochrome bcc. The resulting hybrid supercomplex is stable during extraction and purification in the presence of dodecyl maltoside detergent. It is hoped that this purification procedure will potentiate functional studies of the complex as well as crystallographic studies of drug binding and provide structural insight into a third class of the bc complex superfamily. 相似文献