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361.
362.
Marcelo S. Perlin João F. Caldeira André A. P. Santos Martin Pontuschka 《Journal of forecasting》2017,36(4):454-467
We look into the interaction of Google's search queries and several aspects of international equity markets. Using a novel methodology for selecting words and a vector autoregressive modeling approach, we study whether the search queries of finance‐related words can have an impact on returns, volatility of returns and traded volume in four different English‐speaking countries. We identify several words whose search frequency is associated with changes in the dependent variables. In particular, we find that increases in search queries including the word stock predict increased volatility and decreased index returns over the next week. On top of that, we investigate the performance of a market‐timing strategy based on the search frequency of this word and benchmark it against random words from the Word‐Net database and a naive buy‐and‐hold strategy. The results of this empirical application are positive and particularly stronger during the global crisis of 2009. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
363.
Irina Kerkis Alvaro Rossan de Brandão Prieto da Silva Celine Pompeia Jan Tytgat Paulo L. de Sá Junior 《Cellular and molecular life sciences : CMLS》2017,74(4):647-661
Toxins have been shown to have many biological functions and to constitute a rich source of drugs and biotechnological tools. We focus on toxins that not only have a specific activity, but also contain residues responsible for transmembrane penetration, which can be considered bioportides—a class of cell-penetrating peptides that are also intrinsically bioactive. Bioportides are potential tools in pharmacology and biotechnology as they help deliver substances and nanoparticles to intracellular targets. Bioportides characterized so far are peptides derived from human proteins, such as cytochrome c (CYCS), calcitonin receptor (camptide), and endothelial nitric oxide synthase (nosangiotide). However, toxins are usually disregarded as potential bioportides. In this review, we discuss the inclusion of some toxins and molecules derived thereof as a new class of bioportides based on structure activity relationship, minimization, and biological activity studies. The comparative analysis of the amino acid residue composition of toxin-derived bioportides and their short molecular variants is an innovative analytical strategy which allows us to understand natural toxin multifunctionality in vivo and plan novel pharmacological and biotechnological products. Furthermore, we discuss how many bioportide toxins have a rigid structure with amphiphilic properties important for both cell penetration and bioactivity. 相似文献
364.
G. M. C. Janssen P. Schwertman T. A. T. Wanga R. S. Jahangir Tafrechi P. J. A. van den Broek A. K. Raap 《Cellular and molecular life sciences : CMLS》2009,66(4):721-730
Cytoplasmic translation is under sophisticated control but how cells adapt its rate to constitutive loss of mitochondrial
oxidative phosphorylation is unknown. Here we show that translation is repressed in cells with the pathogenic A3243G mtDNA
mutation or in mtDNA-less ρ0 cells by at least two distinct pathways, one transiently targeting elongation factor eEF-2 and the other initiation factor
eIF-2α constitutively. Under conditions of exponential cell growth and mammalian target of rapamycin (mTOR) activation, eEF-2
becomes transiently phosphorylated by an AMP-activated protein kinase (AMPK)-dependent pathway, especially high in mutant
cells. Independent of AMPK and mTOR, eIF-2α is constitutively phosphorylated in mutant cells, likely a signature of endoplasmic
reticulum (ER)-stress response induced by the loss of oxidative phosphorylation. While the AMPK/eEF-2K/eEF-2 pathway appears
to function in adaptation to physiological fluctuations in ATP levels in the mutant cells, the ER stress signified by constitutive
protein synthesis inhibition through eIF-2α-mediated repression of translation initiation may have pathobiochemical consequences.
Received 29 October 2008; received after revision 11 December 2008; accepted 16 December 2008 相似文献
365.
Functions and pathologies of BiP and its interaction partners 总被引:1,自引:1,他引:0
J. Dudek J. Benedix S. Cappel M. Greiner C. Jalal L. Müller R. Zimmermann 《Cellular and molecular life sciences : CMLS》2009,66(9):1556-1569
The endoplasmic reticulum (ER) is involved in a variety of essential and interconnected processes in human cells, including
protein biogenesis, signal transduction, and calcium homeostasis. The central player in all these processes is the ER-lumenal
polypeptide chain binding protein BiP that acts as a molecular chaperone. BiP belongs to the heat shock protein 70 (Hsp70)
family and crucially depends on a number of interaction partners, including co-chaperones, nucleotide exchange factors, and
signaling molecules. In the course of the last five years, several diseases have been linked to BiP and its interaction partners,
such as a group of infectious diseases that are caused by Shigella toxin producing E. coli. Furthermore, the inherited diseases Marinesco-Sj?gren syndrome, autosomal dominant polycystic liver disease, Wolcott-Rallison
syndrome, and several cancer types can be considered BiP-related diseases. This review summarizes the physiological and pathophysiological
characteristics of BiP and its interaction partners.
Received 20 November 2008; received after revision 09 December 2008; accepted 12 December 2008 相似文献
366.
Ronda Bransteitter Courtney Prochnow Xiaojiang S. Chen 《Cellular and molecular life sciences : CMLS》2009,66(19):3137-3147
The apolipoprotein B mRNA-editing enzyme catalytic polypeptide (APOBEC) family of cytidine deaminases has emerged as an intensively
studied field as a result of their important biological functions. These enzymes are involved in lipid metabolism, antibody
diversification, and the inhibition of retrotransposons, retroviruses, and some DNA viruses. The APOBEC proteins function
in these roles by deaminating single-stranded (ss) DNA or RNA. There are two high-resolution crystal structures available
for the APOBEC family, Apo2 and the C-terminal catalytic domain (CD2) of Apo3G or Apo3G-CD2 [Holden et al. (Nature 456:121–124,
2008); Prochnow et al. (Nature 445:447–451, 2007)]. Additionally, the structure of Apo3G-CD2 has also been determined using
NMR [Chen et al. (Nature 452:116–119, 2008); Furukawa et al. (EMBO J 28:440–451, 2009); Harjes et al. (J Mol Biol, 2009)].
A detailed structural analysis of the APOBEC proteins and a comparison to other zinc-coordinating deaminases can facilitate
our understanding of how APOBEC proteins bind nucleic acids, recognize substrates, and form oligomers. Here, we review the
recent development of structural and functional studies that apply to Apo3G as well as the APOBEC deaminase family. 相似文献
367.
S. Kjellev 《Cellular and molecular life sciences : CMLS》2009,66(8):1350-1369
The trefoil factor family (TFF) comprises a group of small peptides which are highly expressed in tissues containing mucus-producing
cells – especially in the mucosa lining the gastrointestinal tract. The peptides seem crucial for epithelial restitution and
may work via other pathways than the conventional factors involved in restitution. In vitro studies have shown that the TFFs promote restitution using multiple mechanisms. The peptides also have other functionalities
including interactions with the immune system. Moreover, therapeutic effects of the TFFs have been shown in several animal
models of gastrointestinal damage. Still it is not clear which of their in vitro properties are involved in the in vivo mode of action. This review describes the TFF family with emphasis on their biological properties and involvement in mucosal
protection and repair.
Received 10 October 2008; received after revision 07 November 2008; accepted 10 November 2008 相似文献
368.
A. Shukla P. Chaurasia S. R. Bhaumik 《Cellular and molecular life sciences : CMLS》2009,66(8):1419-1433
Methylation of lysine residues of histones is associated with functionally distinct regions of chromatin, and, therefore,
is an important epigenetic mark. Over the past few years, several enzymes that catalyze this covalent modification on different
lysine residues of histones have been discovered. Intriguingly, histone lysine methylation has also been shown to be cross-regulated
by histone ubiquitination or the enzymes that catalyze this modification. These covalent modifications and their cross-talks
play important roles in regulation of gene expression, heterochromatin formation, genome stability, and cancer. Thus, there
has been a very rapid progress within past several years towards elucidating the molecular basis of histone lysine methylation
and ubiquitination, and their aberrations in human diseases. Here, we discuss these covalent modifications with their cross-regulation
and roles in controlling gene expression and stability.
Received 24 September 2008; received after revision 21 November 2008; accepted 28 November 2008 相似文献
369.
J. Kim D. C. Han J. M. Kim S. Y. Lee S. J. Kim J. R. Woo J. W. Lee S.-K. Jung K. S. Yoon H. G. Cheon S. S. Kim S. H. Hong B.-M. Kwon 《Cellular and molecular life sciences : CMLS》2009,66(10):1766-1781
Indenone KR-62776 acts as an agonist of PPARγ without inducing obesity in animal models and cells. X-ray crystallography reveals
that the indenone occupies the binding pocket in a different manner than rosiglitazone. 2-Dimensional gel-electrophoresis
showed that the expression of 42 proteins was altered more than 2.0-fold between KR-62776- or rosiglitazone-treated adipocyte
cells and control cells. Rosiglitazone down-regulated the expression of ERK1/2 and suppressed the phosphorylation of ERK1/2
in these cells. However, the expression of ERK1/2 was up-regulated in KR-62776-treated cells. Phosphorylated ERK1/2, activated
by indenone, affects the localization of PPARγ, suggesting a mechanism for indenone-inhibition of adipogenesis in 3T3-L1 preadipocyte
cells. The preadipocyte cells are treated with ERK1/2 inhibitor PD98059, a large amount of the cells are converted to adipocyte
cells. These results support the conclusion that the localization of PPARγ is one of the key factors explaining the biological
responses of the ligands.
Received 04 March 2009; received after revision 13 March 2009; accepted 17 March 2009 相似文献
370.
Large conductance, Ca2+-activated potassium (BK) channels are widely expressed throughout the animal kingdom and play important roles in many physiological
processes, such as muscle contraction, neural transmission and hearing. These physiological roles derive from the ability
of BK channels to be synergistically activated by membrane voltage, intracellular Ca2+ and other ligands. Similar to voltage-gated K+ channels, BK channels possess a pore-gate domain (S5–S6 transmembrane segments) and a voltage-sensor domain (S1–S4). In addition,
BK channels contain a large cytoplasmic C-terminal domain that serves as the primary ligand sensor. The voltage sensor and
the ligand sensor allosterically control K+ flux through the pore-gate domain in response to various stimuli, thereby linking cellular metabolism and membrane excitability.
This review summarizes the current understanding of these structural domains and their mutual interactions in voltage-, Ca2+ - and Mg2+ -dependent activation of the channel.
Received 25 September 2008; received after revision 23 October 2008; accepted 24 October 2008 相似文献