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51.
Structural comparison of fibroblast growth factor-specific heparan sulfates derived from a growing or differentiating neuroepithelial cell line 总被引:3,自引:1,他引:2
Brickman YG; Nurcombe V; Ford MD; Gallagher JT; Bartlett PF; Turnbull JE 《Glycobiology》1998,8(5):463-471
Heparan sulfate (HS) glycosaminoglycans are essential modulators of
fibroblast growth factor (FGF) activity both in vivo and in vitro, and
appear to act by cross-linking particular forms of FGF to appropriate FGF
receptors. We have recently isolated and characterized two separate HS
pools derived from immortalized embryonic day 10 mouse neuroepithelial 2.3D
cells: one from cells in log growth phase, which greatly potentiates the
activity of FGF-2, and the other from cells undergoing contact-inhibition
and differentiation, which preferentially activates FGF-1. These two pools
of HS have very similar functional activities to those species isolated
from primary neuroepithelial cells at corresponding stages of active
proliferation or differentiation. We present here a structural comparison
between these cell line HS species to establish the nature of the changes
that occur in the biosynthesis of HS. A combination of chemical and
enzymatic cleavage, low pressure chromatography and strong anion-exchange
HPLC were used to generate full chain models of each species. Overall, the
HS pools synthesized in the dividing cell line pools possessed less complex
sulfation than those derived from more differentiated, growth arrested
cells.
相似文献
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53.
Mireille B Johnson Stephen L Clifford Benoît Goossens Silvester Nyakaana Bryan Curran Lee JT White E Jean Wickings Michael W Bruford 《BMC evolutionary biology》2007,7(1):1-14
Background
The mitochondrial genomes of snakes are characterized by an overall evolutionary rate that appears to be one of the most accelerated among vertebrates. They also possess other unusual features, including short tRNAs and other genes, and a duplicated control region that has been stably maintained since it originated more than 70 million years ago. Here, we provide a detailed analysis of evolutionary dynamics in snake mitochondrial genomes to better understand the basis of these extreme characteristics, and to explore the relationship between mitochondrial genome molecular evolution, genome architecture, and molecular function. We sequenced complete mitochondrial genomes from Slowinski's corn snake (Pantherophis slowinskii) and two cottonmouths (Agkistrodon piscivorus) to complement previously existing mitochondrial genomes, and to provide an improved comparative view of how genome architecture affects molecular evolution at contrasting levels of divergence.Results
We present a Bayesian genetic approach that suggests that the duplicated control region can function as an additional origin of heavy strand replication. The two control regions also appear to have different intra-specific versus inter-specific evolutionary dynamics that may be associated with complex modes of concerted evolution. We find that different genomic regions have experienced substantial accelerated evolution along early branches in snakes, with different genes having experienced dramatic accelerations along specific branches. Some of these accelerations appear to coincide with, or subsequent to, the shortening of various mitochondrial genes and the duplication of the control region and flanking tRNAs.Conclusion
Fluctuations in the strength and pattern of selection during snake evolution have had widely varying gene-specific effects on substitution rates, and these rate accelerations may have been functionally related to unusual changes in genomic architecture. The among-lineage and among-gene variation in rate dynamics observed in snakes is the most extreme thus far observed in animal genomes, and provides an important study system for further evaluating the biochemical and physiological basis of evolutionary pressures in vertebrate mitochondria. 相似文献54.
55.
Olivier JT Briët Gawrie NL Galappaththy Flemming Konradsen Priyanie H Amerasinghe Felix P Amerasinghe 《Malaria journal》2005,4(1):1-11
In Vietnam, a large proportion of all malaria cases and deaths occurs in the central mountainous and forested part of the country. Indeed, forest malaria, despite intensive control activities, is still a major problem which raises several questions about its dynamics. A large-scale malaria morbidity survey to measure malaria endemicity and identify important risk factors was carried out in 43 villages situated in a forested area of Ninh Thuan province, south central Vietnam. Four thousand three hundred and six randomly selected individuals, aged 10–60 years, participated in the survey. Rag Lays (86%), traditionally living in the forest and practising "slash and burn" cultivation represented the most common ethnic group. The overall parasite rate was 13.3% (range [0–42.3] while Plasmodium falciparum seroprevalence was 25.5% (range [2.1–75.6]). Mapping of these two variables showed a patchy distribution, suggesting that risk factors other than remoteness and forest proximity modulated the human-vector interactions. This was confirmed by the results of the multivariate-adjusted analysis, showing that forest work was a significant risk factor for malaria infection, further increased by staying in the forest overnight (OR= 2.86; 95%CI [1.62; 5.07]). Rag Lays had a higher risk of malaria infection, which inversely related to education level and socio-economic status. Women were less at risk than men (OR = 0.71; 95%CI [0.59; 0.86]), a possible consequence of different behaviour. This study confirms that malaria endemicity is still relatively high in this area and that the dynamics of transmission is constantly modulated by the behaviour of both humans and vectors. A well-targeted intervention reducing the "vector/forest worker" interaction, based on long-lasting insecticidal material, could be appropriate in this environment. 相似文献
56.
Ana P Teixeira Carlos Alves Paula M Alves Manuel JT Carrondo Rui Oliveira 《BMC bioinformatics》2007,8(1):30
Background
The progress in the "-omic" sciences has allowed a deeper knowledge on many biological systems with industrial interest. This knowledge is still rarely used for advanced bioprocess monitoring and control at the bioreactor level. In this work, a bioprocess control method is presented, which is designed on the basis of the metabolic network of the organism under consideration. The bioprocess dynamics are formulated using hybrid rigorous/data driven systems and its inherent structure is defined by the metabolism elementary modes. 相似文献57.
Carmen Lai Hugo M Horlings Marc J van de Vijver Eric H van Beers Petra M Nederlof Lodewyk FA Wessels Marcel JT Reinders 《BMC bioinformatics》2007,8(1):422
Background
Array comparative genome hybridization (aCGH) provides information about genomic aberrations. Alterations in the DNA copy number may cause the cell to malfunction, leading to cancer. Therefore, the identification of DNA amplifications or deletions across tumors may reveal key genes involved in cancer and improve our understanding of the underlying biological processes associated with the disease. 相似文献58.
59.
Aidlen JT Nazarey PP Kinane TB Donahoe PK Schnitzer JJ Kling DE 《Birth defects research. Part B, Developmental and reproductive toxicology》2007,80(5):406-416
BACKGROUND: Nitrofen is a diphenyl ether that induces a spectrum of birth defects subsequent to administration to pregnant rodents, in which the molecular etiology of these defects are poorly characterized. Because previous reports showed that nitrofen induced apoptosis in undifferentiated P19 teratocarcinoma cells, we hypothesized that undifferentiated fetal cells have greater susceptibility to nitrofen-induced apoptosis than their differentiated derivatives. METHODS: To investigate this hypothesis, cell lines including P19 and F9 were differentiated with retinoic acid into neuronal and endodermal derivatives respectively. Apoptosis was characterized by caspase-3 cleavage and Terminal transferase dUTP nick end labeling (TUNEL) assays. RESULTS: Both differentiated cell-types had reduced nitrofen-induced caspase-3 cleavage and DNA fragmentation compared with the naive controls, strongly suggesting that differentiation of these cells protects against nitrofen-induced apoptosis. In addition, resistance to apoptotic induction was proportional to the expression levels of the differentiation marker, p27 (kip1) while direct proportionality was not observed for the antiapoptotic protein Bcl-2. CONCLUSIONS: These studies show that nitrofen may induce its associated birth defects via a mechanism involving apoptosis of undifferentiated fetal cells. 相似文献
60.
Herman MJ Sontrop Perry D Moerland René van den Ham Marcel JT Reinders Wim FJ Verhaegh 《BMC bioinformatics》2009,10(1):389-22