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851.
Navarro S Aleu J Jiménez M Boix E Cuchillo CM Nogués MV 《Cellular and molecular life sciences : CMLS》2008,65(2):324-337
Human eosinophil cationic protein (ECP)/ ribonuclease 3 (RNase 3) is a protein secreted from the secondary granules of activated
eosinophils. Specific properties of ECP contribute to its cytotoxic activities associated with defense mechanisms. In this
work the ECP cytotoxic activity on eukaryotic cell lines is analyzed. The ECP effects begin with its binding and aggregation
to the cell surface, altering the cell membrane permeability and modifying the cell ionic equilibrium. No internalization
of the protein is observed. These signals induce cell-specific morphological and biochemical changes such as chromatin condensation,
reversion of membrane asymmetry, reactive oxygen species production and activation of caspase-3-like activity and, eventually,
cell death. However, the ribonuclease activity component of ECP is not involved in this process as no RNA degradation is observed.
In summary, the cytotoxic effect of ECP is attained through a mechanism different from that of other cytotoxic RNases and
may be related with the ECP accumulation associated with the inflammatory processes, in which eosinophils are present.
Received 26 October 2007; accepted 23 November 2007 相似文献
852.
Shin JM Vagin O Munson K Kidd M Modlin IM Sachs G 《Cellular and molecular life sciences : CMLS》2008,65(2):264-281
Inhibition of gastric acid secretion is the mainstay of the treatment of gastroesophageal reflux disease and peptic ulceration;
therapies to inhibit acid are among the best-selling drugs worldwide. Highly effective agents targeting the histamine H2 receptor
were first identified in the 1970s. These were followed by the development of irreversible inhibitors of the parietal cell
hydrogen-potassium ATPase (the proton pump inhibitors) that inhibit acid secretion much more effectively. Reviewed here are
the chemistry, biological targets and pharmacology of these drugs, with reference to their current and evolving clinical utilities.
Future directions in the development of acid inhibitory drugs include modifications of current agents and the emergence of
a novel class of agents, the acid pump antagonists.
Received 30 May 2007; received after revision 15 August 2007; accepted 13 September 2007 相似文献
853.
Dolezel D Zdechovanova L Sauman I Hodkova M 《Cellular and molecular life sciences : CMLS》2008,65(6):964-969
Current models state that insect peripheral oscillators are directly responsive to light, while mammalian peripheral clock
genes are coordinated by a master clock in the brain via intermediate factors, possibly hormonal. We show that the expression
levels of two circadian clock genes, period (per) and Par Domain Protein 1 (Pdp1) in the peripheral tissue of an insect model species, the linden bug Pyrrhocoris apterus, are inversely affected by contrasting photoperiods. The effect of photoperiod on per and Pdp1 mRNA levels was found to be mediated by the corpus allatum, an endocrine gland producing juvenile hormone. Our results
provide the first experimental evidence for the effect of an endocrine gland on circadian clock gene expression in insects.
Received 31 October 2007; received after revision 7 January 2008; accepted 9 January 2008
D. Dolezel, L. Zdechovanova: These authors contributed equally to this work. 相似文献
854.
Beside its role as a neurotransmitter in the central nervous system, serotonin appears to be a central physiologic mediator
of many gastrointestinal (GI) functions and a mediator of the brain-gut connection. By acting directly and via modulation
of the enteric nervous system, serotonin has numerous effects on the GI tract. The main gut disturbances in which serotonin
is involved are acute chemotherapy-induced nausea and vomiting, carcinoid syndrome and irritable bowel syndrome. Serotonin
also has mitogenic properties. Platelet-derived serotonin is involved in liver regeneration after partial hepatectomy. In
diseased liver, serotonin may play a crucial role in the progression of hepatic fibrosis and the pathogenesis of steatohepatitis.
Better understanding of the role of the serotonin receptor subtypes and serotonin mechanisms of action in the liver and gut
may open new therapeutic strategies in hepato-gastrointestinal diseases.
Received 15 August 2007; received after revision 1 November 2007; accepted 5 November 2007 相似文献
855.
Cajal bodies (CBs) and Gems are nuclear domains that contain factors responsible for spliceosomal small nuclear ribonucleoprotein
(snRNP) biogenesis. The marker protein for CBs is coilin. In addition to snRNPs, coilin and other factors, canonical CBs contain
the survivor of motor neuron protein (SMN). SMN can also localize to Gems. Considering the important role that coilin plays
in the formation and composition of CBs, we tested the splicing efficiency of several cell lines that vary in regards to coilin
level and modification using an artificial reporter substrate. We found that cells with both hypomethylated coilin and Gems
are more efficient at reporter splicing compared to cells in which SMN localizes to CBs. In contrast, coilin reduction, which
induces Gem formation, decreases cell proliferation and artificial reporter splicing. These findings demonstrate that coilin
modifications or levels impact artificial reporter splicing, possibly by influencing snRNP biogenesis.
Received 26 December 2007; received after revision 5 February 2008; accepted 7 February 2008 相似文献
856.
Myosin V from head to tail 总被引:1,自引:1,他引:0
Trybus KM 《Cellular and molecular life sciences : CMLS》2008,65(9):1378-1389
Myosin V (myoV), a processive cargo transporter, has arguably been the most well-studied unconventional myosin of the past
decade. Considerable structural information is available for the motor domain, the IQ motifs with bound calmodulin or light
chains, and the cargo-binding globular tail, all of which have been crystallized. The repertoire of adapter proteins that
link myoV to a particular cargo is becoming better understood, enabling cellular transport processes to be dissected. MyoV
is processive, meaning that it takes many steps on actin filaments without dissociating. Its extended lever arm results in
long 36-nm steps, making it ideal for single molecule studies of processive movement. In addition, electron microscopy revealed
the structure of the inactive, folded conformation of myoV when it is not transporting cargo. This review provides a background
on myoV, and highlights recent discoveries that show why myoV will continue to be an active focus of investigation.
Received 31 October 2007; received after revision 4 December 2007; accepted 2 January 2008 相似文献
857.
Molecular and Cellular Basis of Regeneration and Tissue Repair 总被引:2,自引:0,他引:2
The Xenopus tadpole is a favourable organism for regeneration research because it is suitable for a wide range of micromanipulative procedures and for a wide range of transgenic methods. Combination of these techniques enables genes to be activated or inhibited at specific times and in specific tissue types to a much higher degree than in any other organism capable of regeneration. Regenerating systems include the tail, the limb buds and the lens. The study of tail regeneration has shown that each tissue type supplies the cells for its own replacement: there is no detectable de-differentiation or metaplasia. Signalling systems needed for regeneration include the BMP and Notch signalling pathways, and perhaps also the Wnt and FGF pathways. The limb buds will regenerate completely at early stages, but not once they are fully differentiated. This provides a good opportunity to study the loss of regenerative ability using transgenic methods. 相似文献
858.
Molecular and Cellular Basis of Regeneration and Tissue Repair 总被引:3,自引:0,他引:3
Rossi L Salvetti A Batistoni R Deri P Gremigni V 《Cellular and molecular life sciences : CMLS》2008,65(1):16-23
Planarians possess amazing abilities to regulate tissue homeostasis and regenerate missing body parts. These features reside on the presence of a population of pluripotent/totipotent stem cells, the neoblasts, which are considered as the only planarian cells able to proliferate in the asexual strains. Neoblast distribution has been identified by mapping the cells incorporating bromodeoxyuridine, analyzing mitotic figures and using cell proliferation markers. Recently identified molecular markers specifically label subgroups of neoblasts, revealing thus the heterogeneity of the planarian stem cell population. Therefore, the apparent totipotency of neoblasts probably reflects the composite activities of multiple stem cell types. First steps have been undertaken to understand how neoblasts and differentiated cells communicate with each other to adapt the self-renewal and differentiation rates of neoblasts to the demands of the body. Moreover, the introduction of molecular resource database on planarians now paves the way to renewed strategies to understand planarian regeneration and stem cell-related issues. 相似文献
859.
The utility F-box for protein destruction 总被引:3,自引:1,他引:2
A signature feature of all living organisms is their utilization of proteins to construct molecular machineries that undertake the complex network of cellular activities. The abundance of a protein element is temporally and spatially regulated in two opposing aspects: de novo synthesis to manufacture the required amount of the protein, and destruction of the protein when it is in excess or no longer needed. One major route of protein destruction is coordinated by a set of conserved molecules, the F-box proteins, which promote ubiquitination in the ubiquitin-proteasome pathway. Here we discuss the functions of F-box proteins in several cellular scenarios including cell cycle progression, synapse formation, plant hormone responses, and the circadian clock. We particularly emphasize the mechanisms whereby F-box proteins recruit specific substrates and regulate their abundance in the context of SCF E3 ligases. For some exceptions, we also review how F-box proteins function through non-SCF mechanisms. 相似文献
860.
The potential effects of synthetic unmethylated oligodeoxynucleotides (ODN) containing CpG motifs, mimicking bacterial DNA, has never been evaluated on the immune response in the teleost fish gilthead seabream (Sparus aurata), the most important fish species in Mediterranean aquaculture. First, binding and competition studies have demonstrated that binding is saturated and promiscuous, suggesting the participation of several receptors. Moreover, leucocyte cytotoxic (NCC) activity, production of ROIs (reactive oxygen intermediates), and expression of immune-relevant genes was greatly primed by ODNs. Focusing on the mechanism, the TLR9 gene is widely distributed in seabream tissues and differently regulated in vitro by several stimuli. Moreover, and for the first time in fish, TLR9 mRNA has been detected in lymphocytes as the main cell-source. To conclude, ODNs containing GACGTT, GTCGTT (optimal for mouse and human, respectively) or AACGTT motifs are the most potent inducers of seabream immunity, whilst the involvement of TLR9 is under debate. 相似文献