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11.
Emmanuel Martin Valère Cacheux Hélène Cavé Jean Michel Lapierre Denis Le Paslier Bernard Grandchamp 《Human genetics》1995,96(6):668-670
CDKN4/p27Kip1 is a cyclin-dependent kinase (Cdk) inhibitor implicated in G1 phase arrest, which negatively regulates G1 phase progression in response to TGF, and might represent a tumor suppressor gene. We report here the chromosomal assignment of the human CDKN4 gene to chromosome 12p12.3 in close proximity to highly polymorphic microsatellite markers. 相似文献
12.
This work investigates the influence of environmental inducers on the organization of cell regulation networks, using a connectionist approach. Protein interactions are modeled by an asymmetrical recurrent network, the units of which take continuous values. In contrast to classical models, we explicitly introduce a genome to encode the architecture of the system. This feature enables us to introduce an evolution model, in which a genetic algorithm that mimics the effects of evolution on proteins mutual interactions is used. We assume an efficient system to respond to persistent environmental stimuli, independently of their amplitude. Results are presented that show a structuration of the network with the emergence of specialized hierarchical structures. These structures seem to drive the system at the edge of chaos, so that it can present adapted responses to significant environmental changes. 相似文献
13.
The subunit MW of Dioscorea bulbifera polyphenol oxidase (MW 115 000 ± 2000) determined by SDS-PAGE is ca. 31 000 indicating that the enzyme is an oligomeric protein with four subunits. Ki values of various inhibitors and their modes of inhibition have been determined with catechol and pyrogallol as substrates. p-Nitrophenol, p-cresol, quinoline and resorcinol are competitive inhibitors of catechol binding while only orcinol and p-nitrophenol behave in the same way towards pyrogallol as substrate. From the effect of pH on Vmax, groups with pK values ca. 4.7 and 6.8 have been identified to be involved in catalytic activity. The Arrhenius activation energy (Ea) at pH 4.0 is 8.9 kcal/mol between 40–65°. At pH 7.0, the value is 22.1 kcal/mol between 40 and 60°. The enthalpies (ΔH) at pH 4.0 and pH 7.0 are 2.3 kcal/mol and 32.4 kcal/mol respectively. The results are discussed considering the conformational changes of the enzyme during substrate binding. 相似文献
14.
Michael O. Eze Emmanuel I. Okafor Charles E. Okoronkwo 《Applied microbiology and biotechnology》1982,16(1):52-55
Summary The influence of the microenvironment on the metabolic behaviour of immobilized cells is discussed in relation to literature data. A model is proposed in which decreased water activity and/or oxygen deficiency result in changed yields and/or new metabolic behaviour of the immobilized cells. 相似文献
15.
In a comparison of the polyphenol oxidase activity of various species of yam tubers the greatest enzyme activity was found in D. bulbifera. The enzyme was purified from acetone powder extracts of this plant. Ammonium sulphate fractionation, followed by ion exchange chromatography and gel filtration gave 22-fold purification. The final product gave a single band on polyacrylamide disc gel electrophoresis. The purified enzyme showed activity towards catechol, pyrogallol and dl-β-3,4-dihydroxyphenylalanine (dl-DOPA) and had a MW 115000 ± 2000. It was characterized by response to various inhibitors. β-Mercaptoethanol, dithioerythritol, l-cysteine, sodium metabisulphite and KCN inhibited strongly. 相似文献
16.
17.
C Condé X Rambout M Lebrun A Lecat E Di Valentin F Dequiedt J Piette G Gloire S Legrand 《PloS one》2012,7(7):e41005
SHIP-1 is an inositol phosphatase predominantly expressed in hematopoietic cells. Over the ten past years, SHIP-1 has been described as an important regulator of immune functions. Here, we characterize a new inhibitory function for SHIP-1 in NOD2 signaling. NOD2 is a crucial cytoplasmic bacterial sensor that activates proinflammatory and antimicrobial responses upon bacterial invasion. We observed that SHIP-1 decreases NOD2-induced NF-κB activation in macrophages. This negative regulation relies on its interaction with XIAP. Indeed, we observed that XIAP is an essential mediator of the NOD2 signaling pathway that enables proper NF-κB activation in macrophages. Upon NOD2 activation, SHIP-1 C-terminal proline rich domain (PRD) interacts with XIAP, thereby disturbing the interaction between XIAP and RIP2 in order to decrease NF-κB signaling. 相似文献
18.
Emmanuel Serrano Russell Alpizar-Jara Nicolas Morellet Aidan Jonathan Mark Hewison 《European Journal of Wildlife Research》2008,54(4):675-680
From a literature review of five wildlife ecology journals since 1937, we document how using indices to monitor ungulate body
condition is common practice, with the kidney fat index (KFI = weight of fat around the kidneys/weight of kidneys without
fat × 100) as the favoured tool (82% of studies). In this context, we highlight the problems of using indices when underlying
statistical assumptions are not met (isometry, parallel slopes between treatments). We show, with real and simulated data
for two cervids with contrasting fat storage strategies, how results from analysis of variance of KFI values differ from analysis
of covariance (ANCOVA) of raw data. We conclude that the KFI is affected by the restrictions typically associated with derived
index values, and as a consequence, statistical analysis of the KFI could generate spurious results leading to erroneous interpretations
concerning variation in body condition of ungulate populations. Thus, we recommend analysing fat weight as an untransformed
variable in ANCOVA (kidney weight as covariate) to describe body condition variation in ungulates.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
20.
The enterotoxin gene (cpe) of Clostridium perfringens can be chromosomal or plasmid-borne 总被引:3,自引:0,他引:3
Emmanuel Cornillot † Brigitte Saint-Joanis Georges Daube Sei-ichi Katayama Per Einar Granum Bruno Canard ‡ Stewart T. Cole 《Molecular microbiology》1995,15(4):639-647
The location of the cpe gene, encoding the enterotoxin responsible for food poisoning in humans, has been studied in a series of enterotoxigenic Ciostridium perfringens strains by means of pulsed field gel electrophoresis of genomic DNA. The cpe gene was found at the same chromosomal locus in strains associated with food poisoning in humans and was shown to be linked to a repetitive sequence, the Hin dlll repeat, and an open reading frame, ORF3, that may be part of an insertion sequence. In contrast, when the strains originated from domesticated livestock cpe was located on a large episome where it was often close to a copy of the transposable element IS 1151. In these cases, the Hin dlll repeat was not linked to the cpe gene although this was generally preceded by ORF3. 相似文献