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排序方式: 共有98条查询结果,搜索用时 109 毫秒
71.
Maria José de los Santos Pilar Gámiz José María de los Santos Josep Lluís Romero Nicolás Prados Cristina Alonso José Remohí Francisco Dominguez 《PloS one》2015,10(11)
Despite efforts made to improve the in vitro embryo culture conditions used during assisted reproduction procedures, human embryos must adapt to different in vitro oxygen concentrations and the new metabolic milieu provided by the diverse culture media used for such protocols. It has been shown that the embryo culture environment can affect not only cellular metabolism, but also gene expression in different species of mammalian embryos. Therefore we wanted to compare the metabolic footprint left by human cleavage-stage embryos under two types of oxygen atmospheric culture conditions (6% and 20% O2). The spent culture media from 39 transferred and implanted embryos from a total of 22 patients undergoing egg donation treatment was analyzed; 23 embryos came from 13 patients in the 6% oxygen concentration group, and 16 embryos from 9 patients were used in the 20% oxygen concentration group. The multivariate statistics we used in our analysis showed that human cleavage-stage embryos grown under both types of oxygen concentration left a similar metabolic fingerprint. We failed to observe any change in the net depletion or release of relevant analytes, such as glucose and especially fatty acids, by human cleavage-stage embryos under either type of culture condition. Therefore it seems that low oxygen tension during embryo culture does not alter the global metabolism of human cleavage-stage embryos. 相似文献
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74.
Nimmy Mohan Sudheesh AP Nimmy Francis Richard Anderson Rakesh S. Laishram 《Nucleic acids research》2015,43(14):7005-7020
Star-PAP is a nuclear non-canonical poly(A) polymerase (PAP) that shows specificity toward mRNA targets. Star-PAP activity is stimulated by lipid messenger phosphatidyl inositol 4,5 bisphoshate (PI4,5P2) and is regulated by the associated Type I phosphatidylinositol-4-phosphate 5-kinase that synthesizes PI4,5P2 as well as protein kinases. These associated kinases act as coactivators of Star-PAP that regulates its activity and specificity toward mRNAs, yet the mechanism of control of these interactions are not defined. We identified a phosphorylated residue (serine 6, S6) on Star-PAP in the zinc finger region, the domain required for PIPKIα interaction. We show that S6 is phosphorylated by CKIα within the nucleus which is required for Star-PAP nuclear retention and interaction with PIPKIα. Unlike the CKIα mediated phosphorylation at the catalytic domain, Star-PAP S6 phosphorylation is insensitive to oxidative stress suggesting a signal mediated regulation of CKIα activity. S6 phosphorylation together with coactivator PIPKIα controlled select subset of Star-PAP target messages by regulating Star-PAP-mRNA association. Our results establish a novel role for phosphorylation in determining Star-PAP target mRNA specificity and regulation of 3′-end processing. 相似文献
75.
Martínez-Sanz E Casado-Gómez I Martín C López-Gordillo Y González P Rodríguez-Bobada C Paradas I González-Meli B Maldonado E Maestro C Prados JC Martínez-Álvarez C 《Laboratory animals》2011,45(2):70-80
In humans, cleft palate (CP) is one of the most common malformations. Although surgeons use palatoplasty to close CP defects in children, its consequences for subsequent facial growth have prompted investigations into other novel surgical alternatives. The animal models of CP used to evaluate new surgical treatments are frequently obtained by creating surgically induced clefts in adult dogs. This procedure has been ethically criticized due to its severity and questionable value as an animal model for human CP. Dogs born with a congenital CP would be much better for this purpose, provided they developed CP at a sufficient rate and could be fed. Up until now, feeding these pups carried the risk of aspiration pneumonia, while impeding normal suckling and chewing, and thus compromising orofacial growth. We developed a technique for feeding dog pups with CP from birth to the time of surgery using two old Spanish pointer dog pups bearing a complete CP. This dog strain develops CP in 15-20% of the offspring spontaneously. Custom-made feeding teats and palatal prostheses adapted to the pups' palates were made from thermoplastic plates. This feeding technique allowed lactation, eating and drinking in the pups with CP, with only sporadic rhinitis. To determine whether the use of this palatal prosthesis interferes with palatal growth, the palates of three littermate German shorthaired pointer pups without CP, either wearing or not wearing (controls) the prosthesis, were measured. The results showed that the permanent use of this prosthesis does not impede palatal growth in the pups. 相似文献
76.
García MA Carrasco E Aguilera M Alvarez P Rivas C Campos JM Prados JC Calleja MA Esteban M Marchal JA Aránega A 《PloS one》2011,6(8):e23887
The chemotherapeutic drug 5-FU is widely used in the treatment of a range of cancers, but resistance to the drug remains a major clinical problem. Since defects in the mediators of apoptosis may account for chemo-resistance, the identification of new targets involved in 5-FU-induced apoptosis is of main clinical interest. We have identified the ds-RNA-dependent protein kinase (PKR) as a key molecular target of 5-FU involved in apoptosis induction in human colon and breast cancer cell lines. PKR distribution and activation, apoptosis induction and cytotoxic effects were analyzed during 5-FU and 5-FU/IFNα treatment in several colon and breast cancer cell lines with different p53 status. PKR protein was activated by 5-FU treatment in a p53-independent manner, inducing phosphorylation of the protein synthesis translation initiation factor eIF-2α and cell death by apoptosis. Furthermore, PKR interference promoted a decreased response to 5-FU treatment and those cells were not affected by the synergistic antitumor activity of 5-FU/IFNα combination. These results, taken together, provide evidence that PKR is a key molecular target of 5-FU with potential relevance in the clinical use of this drug. 相似文献
77.
In two experiments, rats were given serial forward (the target followed by the distractor) or backward (the distractor followed by the target) exposure to two compound flavor stimuli that could be either similar (Salt-X/AX) or dissimilar (Salt-X/AY, Experiment 1; Salt/AX, Experiment 2). Following pre-exposure, the Salt element was presented in a compound with a novel flavor, N. The salience or effectiveness of the Salt element was then assessed by presenting the new flavor, N, under a state of salt appetite. Experiments 1 and 2 revealed that the order of presentation modulated the habituation of the Salt element only when the distractor was similar to the target: the Salt element was more salient after forward than backward pre-exposure. In the groups Dissimilar the order of pre-exposure was irrelevant; however, when the Salt element was presented in compound with a second element (Salt-X, Experiment 1), its salience was preserved, whereas when it was presented alone (Salt, Experiment 2) its salience was significantly reduced. These results, which are discussed in terms of Wagner (1981) theory of habituation, inform about the way in which stimuli presented closely in time are processed. 相似文献
78.
St John JA Braun EL Isberg SR Miles LG Chong AY Gongora J Dalzell P Moran C Bed'hom B Abzhanov A Burgess SC Cooksey AM Castoe TA Crawford NG Densmore LD Drew JC Edwards SV Faircloth BC Fujita MK Greenwold MJ Hoffmann FG Howard JM Iguchi T Janes DE Khan SY Kohno S de Koning AJ Lance SL McCarthy FM McCormack JE Merchant ME Peterson DG Pollock DD Pourmand N Raney BJ Roessler KA Sanford JR Sawyer RH Schmidt CJ Triplett EW Tuberville TD Venegas-Anaya M Howard JT Jarvis ED Guillette LJ Glenn TC 《Genome biology》2012,13(1):415-12
The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described. 相似文献
79.
Simultaneous saccharification and fermentation of straw to ethanol using the thermotolerant yeast strain Kluyveromyces marxianus imb3 总被引:1,自引:0,他引:1
The thermotolerant, ethanol-producing yeast strain Kluyveromyces marxianus IMB3 was grown at 45°C on media containing 2, 4 and 6 % (w/v) pulverized barley straw and supplemented with 2% (v/v) cellulase. Maximum ethanol concentrations produced were 2, 3 and 3.6g/l, respectively. When the pulverized straw was replaced by NaOH pretreated straw (at 2, 4 and 6% (w/v); based on original untreated straw), ethanol concentrations increased to maxima of 3.9, 8, and 12g/l, respectively. The ethanol yields amount to 20g ethanol from 100g of straw. 相似文献
80.
Phylogenetic analysis of slippage-like sequence variation in the V4 rRNA expansion segment in tiger beetles (Cicindelidae) 总被引:1,自引:1,他引:0
Sequence variation in the middle part of the small-subunit rRNA was studied
for representatives of the major groups in the family Cicindelidae
(Coleoptera). All taxa exhibited a much expanded segment in variable region
V4 compared to D. melanogaster. This expanded segment was not found in
other groups of beetles, including three taxa in the closely related
Carabidae. Secondary structure predictions indicate that the expanded
segment folds into a single stem-loop structure in all taxa. Despite its
structural conservation, the fragment differs strongly in primary sequence,
even between closely related sister taxa. Several features of these
sequences are consistent with slippage replication as the mechanism that
has generated this sequence variation: the level of internal sequence
repetition as measured by the relative simplicity factor (RSF), its
variation in length between close relatives, and the strong nucleotide bias
compared to the remainder of the gene. With few exceptions, there was also
a correlation between sequence length and the level of sequence repetition,
frequently interpreted as the result of slippage. Phylogenies inferred from
the expansion segment were not consistent with existing hypotheses from
other molecular data for the group. This indicates that DNA sequences in
this region are not homologous throughout the entire Cicindelidae, but it
leaves open the possibility that this expansion segment can be used for
phylogeny reconstruction within subgroups. The implications of a
phylogenetic approach to the understanding of slippage-like evolution are
discussed.
相似文献