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11.
Mónica López Fanarraga Javier Bellido Cristina Jaén Juan Carlos Villegas Juan Carlos Zabala 《PloS one》2010,5(1)
Microtubule-organizing centers recruit α- and β-tubulin polypeptides for microtubule nucleation. Tubulin synthesis is complex, requiring five specific cofactors, designated tubulin cofactors (TBCs) A–E, which contribute to various aspects of microtubule dynamics in vivo. Here, we show that tubulin cofactor D (TBCD) is concentrated at the centrosome and midbody, where it participates in centriologenesis, spindle organization, and cell abscission. TBCD exhibits a cell-cycle-specific pattern, localizing on the daughter centriole at G1 and on procentrioles by S, and disappearing from older centrioles at telophase as the protein is recruited to the midbody. Our data show that TBCD overexpression results in microtubule release from the centrosome and G1 arrest, whereas its depletion produces mitotic aberrations and incomplete microtubule retraction at the midbody during cytokinesis. TBCD is recruited to the centriole replication site at the onset of the centrosome duplication cycle. A role in centriologenesis is further supported in differentiating ciliated cells, where TBCD is organized into “centriolar rosettes”. These data suggest that TBCD participates in both canonical and de novo centriolar assembly pathways. 相似文献
12.
13.
C González-Bosch V J Miralles J Hernández-Yago S Grisolía 《Biochemical and biophysical research communications》1987,146(3):1318-1323
Apocytochrome c, the cytosolic precursor of cytochrome c, competes with the precursor of ornithine carbamoyltransferase (OCT) for entry into isolated rat liver mitochondria. 相似文献
14.
Spermidine and spermine stimulate the transport of the precursor of ornithine carbamoyltransferase into rat liver mitochondria 总被引:1,自引:0,他引:1
C González-Bosch V J Miralles J Hernández-Yago S Grisolia 《Biochemical and biophysical research communications》1987,149(1):21-26
We have examined the effect of low molecular weight components of the transport mixture generally used for the import of rat liver pre-ornithine carbamoyltransferase by isolated rat liver mitochondria. These studies revealed that spermidine and spermine, at physiological concentrations, stimulate the transport of the precursor of ornithine carbamoyltransferase into mitochondria. This stimulatory effect of spermidine and spermine is concentration-dependent and is completely inhibited at higher than physiological concentrations (20 mM for spermidine and 4 mM for spermine). Magnesium ions, which also have a stimulatory effect, inhibit the stimulatory effect of spermidine. 相似文献
15.
16.
Suárez-Cortez R Alvarez-Gallegos J González-Mora E 《Biotechnology and bioengineering》1989,33(4):377-385
The design of a sliding controller for a continuous fermentation process is presented. The results obtained by simulation have proved the control scheme to be very robust. Regulation of substrate concentration at its optimal value has been achieved even though process parameters change their nominal values. Chattering effects are decreased by introducing a minor modification of the control variable around the sliding surface. 相似文献
17.
J M Afonso M Hernández J M Larruga V M Cabrera A M González 《Human biology; an international record of research》1989,61(4):543-549
We analyzed the genetic polymorphism of eight red cell enzymes in samples from different geographical areas of Tenerife and the Iberian peninsula. The gene frequency heterogeneity found within the Tenerife samples was at the same level as that of Tenerife-mainland comparisons. The presence of the Negroid G6PD A+ allele in the Tenerife samples is evidence of an African admixture with a mean estimation of 4.5%. 相似文献
18.
Pollution indicators in Do?ana National Park show a cyclic seasonal pattern with maximum level in the autumn and minimum in the spring. While faecal streptococci proved to be the best indicator micro-organisms in this type of salty, alkaline environment, total coliforms gave an overestimation of pollution because of the presence of hydroteluric coliforms. 相似文献
19.
Enrique Palacián Pedro J. González Manuel Piñeiro Francisco Hernández 《Molecular and cellular biochemistry》1990,97(2):101-111
Dissociation of protein-containing structures by modification of protein amino groups with dicarboxylic acid anhydrides is a mild procedure which, in some cases, offers advantages over treatment with alternative dissociating agents, such as urea, guanidine hydrochloride, detergents, high ionic strength, and extremes of pH: In addition to dissociating multimeric proteins and protein aggregates, dicarboxylic acid anhydrides are effective dissociating agents for membrane-bound proteins and nucleoprotein particles. With most dicarboxylic acid anhydrides reviewed, the introduced reagent residues can be eliminated under moderate acid conditions, which allows the purification of unmodified individual components, and the use of disassembly-reconstitution systems valuable for investigating the structural and functional roles played by the individual components of complex particles:Each reagent can be suitable for a particular purpose, depending on the required specificity of the modification and stability of the modified groups: The stability of the acylated amino groups ranges from the very stable succinylated amino groups to the very labile acylation obtained with dimethylmaleic anhydride: Between these extremes, the stability of the modified amino groups decreases stepwise in the following order: maleic, exo-cis-3,6-endoxo-4-tetrahydrophthalic, citraconic, and 3,4,5,6-tetrahydrophthalic anhydride. With respect to the selectivity of the produced modification, little or no modification of hydroxyamino acid and cysteine residues has been observed with dimethylmaleic, exo-cis-3,6-endoxo-4-tetrahydrophthalic, and 3,4,5,6-tetrahydrophthalic anhydrides: With the other reagents, the extent of modification of hydroxyamino acid residues increases in the order citraconic, maleic and succinic anhydride: Citraconic and maleic anhydrides can produce irreversible modification of cysteine residues, the reactivity of sulfhydryl groups being higher with maleic anhydride: 相似文献
20.
Cristina Sánchez-Roldán Antonio Heredia Victoriano Valpuesta Martin J. Bukovac 《Journal of Plant Growth Regulation》1990,9(1-3):171-174
The indole-3-acetic acid (IAA) content in peach pericarp (Prunus persica L. Batsch cv. Merry) was highest at early stage I of development (200 ng/g fresh wt), decreased to the lowest level during stage II, and rose again at stage III to 60–70 ng/g fresh wt. High activity of glutamine synthetase was found in the pericarp during stage I. The soluble peroxidase activity was highest in the meso- and exocarp at stage II, and isoenzymatic changes in this fraction corresponded to the transition from cationic isoenzymes, predominant at stage I, to anionic isoenzymes at stage III. The ionically bound peroxidase activity in these tissues was highest at stage I. The three developmental stages showed marked differences in auxin content and enzyme activities; for peroxidases these changes reflect a developmental expression pattern for the isoenzymes. 相似文献