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81.
The induction by adenovirus-12 of a site-specific gap and assignment of the chimpanzee genes for thymidine kinase and galactokinase were studied by utilizing chimpanzee-mouse hybrid cells. It has been shown that adenovirus-12 induces a specific gap in the long arm of human chromosome 17 (HS 17); with chimpanzee-mouse hybrid cells the specific gap appears on the short arm of the chimpanzee homolog [PTR 19 (HS 17)] of HS 17. This result supports the proposed relationship of HS 17 to PTR 19 (HS 17) by means of a pericentric inversion. The chimpanzee thymidine kinase and galactokinase genes were assigned to PTR 19 (HS 17), further confirming the homology to HS 17. Other syntenic relationships and gene assignments were consistent with proposed homologies between chimpanzee and human chromosomes. 相似文献
82.
CDP-diacylglycerol for polyglycerophosphatide biogenesis can be synthesized within rat liver mitochondria. This membrane-associated enzyme was predominantly located in the inner mitochondrial membrane. GTP had a significant effect in activating the microsomal CDP-diacylglycerol synthase, especially if the microsomes were preincubated with GTP in the presence of phosphatidic acid. This stimulatory effect of GTP on the microsomal enzyme was not detected in the mitochondrial fractions. The enzymes could be solubilized from the membrane fractions using CHAPS, and the detergent-soluble activity partially restored by addition of phospholipids. Mitochondrial and microsomal CDP-diacylglycerol synthase activity could be completely separated by anion-exchange column chromatography. The mitochondrial and microsomal CDP-diacylglycerol synthases appear to be two distinct enzymes with different localization and regulatory characteristics. 相似文献
83.
Melinda J. Wilcock Barbara M. McDougall Robert J. Seviour 《FEMS microbiology letters》1992,97(1-2):67-72
Abstract Acremonium persicinum grown in batch culture with ammonium tartrate as the nitrogen source possessed an NADP+ -dependent glutamate dehydrogenase and a glutamine synthetase. Glutamate synthase was not detected under the culture conditions used. Kinetic studies of the NADP+ -dependent glutamate dehydrogenase at 25°C and pH 7.6 revealed an apparent K m of 3.2 × 10−4 M for 2-oxoglutarate and an apparent K m of 1.0 × 10−5 M for ammonium ions, with corresponding apparent V max values of 0.089 and 0.13 μmol substrate converted/min/mg of protein, respectively. Glutamine synthetase was measured by the γ-glutamyl transferase reaction at 30°C and pH 7.55. This transferase reaction of glutamine synthetase had a higher rate at 30°C than at 25°C or 37°C. 相似文献
84.
A fragile site in the human U2 small nuclear RNA gene cluster is revealed by adenovirus type 12 infection. 总被引:7,自引:2,他引:5
D M Durnam J C Menninger S H Chandler P P Smith J K McDougall 《Molecular and cellular biology》1988,8(5):1863-1867
Using in situ hybridization, we found that the U2 small nuclear RNA gene cluster mapped very close to and was frequently disrupted by the gaps and breaks induced specifically in the human 17q21-q22 region by highly oncogenic adenovirus type 12 (Ad12). Restriction mapping revealed no structural alterations in the U2 gene locus as a result of Ad12 infection. Likewise, no Ad12-induced alterations in U2 RNA levels were detected. We estimate that the maximum size of the region specifically disrupted by this virus was less than 350 to 700 kilobases. A comparison of these data with similar data regarding biochemically induced fragile sites was made. 相似文献
85.
86.
87.
Integrating animal temperament within ecology and evolution 总被引:9,自引:0,他引:9
Réale D Reader SM Sol D McDougall PT Dingemanse NJ 《Biological reviews of the Cambridge Philosophical Society》2007,82(2):291-318
Temperament describes the idea that individual behavioural differences are repeatable over time and across situations. This common phenomenon covers numerous traits, such as aggressiveness, avoidance of novelty, willingness to take risks, exploration, and sociality. The study of temperament is central to animal psychology, behavioural genetics, pharmacology, and animal husbandry, but relatively few studies have examined the ecology and evolution of temperament traits. This situation is surprising, given that temperament is likely to exert an important influence on many aspects of animal ecology and evolution, and that individual variation in temperament appears to be pervasive amongst animal species. Possible explanations for this neglect of temperament include a perceived irrelevance, an insufficient understanding of the link between temperament traits and fitness, and a lack of coherence in terminology with similar traits often given different names, or different traits given the same name. We propose that temperament can and should be studied within an evolutionary ecology framework and provide a terminology that could be used as a working tool for ecological studies of temperament. Our terminology includes five major temperament trait categories: shyness-boldness, exploration-avoidance, activity, sociability and aggressiveness. This terminology does not make inferences regarding underlying dispositions or psychological processes, which may have restrained ecologists and evolutionary biologists from working on these traits. We present extensive literature reviews that demonstrate that temperament traits are heritable, and linked to fitness and to several other traits of importance to ecology and evolution. Furthermore, we describe ecologically relevant measurement methods and point to several ecological and evolutionary topics that would benefit from considering temperament, such as phenotypic plasticity, conservation biology, population sampling, and invasion biology. 相似文献
88.
In a previous article [Carbohydr. Res.2001, 331, 163-171] two different structures for the possible modular repeating unit of the extracellular beta-glucan, epiglucan produced by the fungus Epicoccum nigrum strain F19 were proposed. Clarifying which was the more likely one was considered essential before attempts were made to understand how epiglucan was assembled by this fungus. Data from Smith degradation analyses of epiglucan were consistent with the repeating unit of structure I, where single glucosyl residues are attached by (1-->6)-beta-linkages to two out of every three glucosyl residues in the (1-->3)-beta-linked glucan backbone. Repeated Smith degradations of 14C-glucose labelled epiglucan showed that chain elongation occurred from its non-reducing end. Side chain insertion into the growing glucan was followed by analysis of real time incorporation of 13C-glucose into epiglucan by 13C NMR, and 14C-glucose by enzymic digestion of the synthesised 14C-epiglucan. All data obtained were consistent with the view that single (1-->6)-beta-linked glucosyl side residues are inserted simultaneously as the glucan backbone elongates. 相似文献
89.
Daniel J Jackson Carmel McDougall Kathryn Green Fiona Simpson Gert Wörheide Bernard M Degnan 《BMC biology》2006,4(1):40-10
Background
Instructions to fabricate mineralized structures with distinct nanoscale architectures, such as seashells and coral and vertebrate skeletons, are encoded in the genomes of a wide variety of animals. In mollusks, the mantle is responsible for the extracellular production of the shell, directing the ordered biomineralization of CaCO3 and the deposition of architectural and color patterns. The evolutionary origins of the ability to synthesize calcified structures across various metazoan taxa remain obscure, with only a small number of protein families identified from molluskan shells. The recent sequencing of a wide range of metazoan genomes coupled with the analysis of gene expression in non-model animals has allowed us to investigate the evolution and process of biomineralization in gastropod mollusks. 相似文献90.
Arjan D van Zuilen Ingeborgh van der Tweel Peter J Blankestijn Michiel L Bots Marjolijn van Buren Marc AGJ ten Dam Karin AH Kaasjager Peter JG van de Ven Gerald Vervoort Louis-Jean Vleming Gerry Ligtenberg Jack FM Wetzels 《Trials》2006,7(1):1-9