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排序方式: 共有216条查询结果,搜索用时 109 毫秒
51.
Stefano Santaguida Anthony Tighe Anna Morena D'Alise Stephen S. Taylor Andrea Musacchio 《The Journal of cell biology》2010,190(1):73-87
The catalytic activity of the MPS1 kinase is crucial for the spindle assembly checkpoint and for chromosome biorientation on the mitotic spindle. We report that the small molecule reversine is a potent mitotic inhibitor of MPS1. Reversine inhibits the spindle assembly checkpoint in a dose-dependent manner. Its addition to mitotic HeLa cells causes the ejection of Mad1 and the ROD–ZWILCH–ZW10 complex, both of which are important for the spindle checkpoint, from unattached kinetochores. By using reversine, we also demonstrate that MPS1 is required for the correction of improper chromosome–microtubule attachments. We provide evidence that MPS1 acts downstream from the AURORA B kinase, another crucial component of the error correction pathway. Our experiments describe a very useful tool to interfere with MPS1 activity in human cells. They also shed light on the relationship between the error correction pathway and the spindle checkpoint and suggest that these processes are coregulated and are likely to share at least a subset of their catalytic machinery. 相似文献
52.
A Tripiciano C Peluso A R Morena F Palombi M Stefanini E Ziparo M Yanagisawa A Filippini 《The Journal of cell biology》1999,145(5):1027-1038
The potent smooth muscle agonist endothelin-1 (ET-1) is involved in the local control of seminiferous tubule contractility, which results in the forward propulsion of tubular fluid and spermatozoa, through its action on peritubular myoid cells. ET-1, known to be produced in the seminiferous epithelium by Sertoli cells, is derived from the inactive intermediate big endothelin-1 (big ET-1) through a specific cleavage operated by the endothelin-converting enzyme (ECE), a membrane-bound metalloprotease with ectoenzymatic activity. The data presented suggest that the timing of seminiferous tubule contractility is controlled locally by the cyclic interplay between different cell types. We have studied the expression of ECE by Sertoli cells and used myoid cell cultures and seminiferous tubule explants to monitor the biological activity of the enzymatic reaction product. Northern blot analysis showed that ECE-1 (and not ECE-2) is specifically expressed in Sertoli cells; competitive enzyme immunoassay of ET production showed that Sertoli cell monolayers are capable of cleaving big ET-1, an activity inhibited by the ECE inhibitor phosphoramidon. Microfluorimetric analysis of intracellular calcium mobilization in single cells showed that myoid cells do not respond to big endothelin, nor to Sertoli cell plain medium, but to the medium conditioned by Sertoli cells in the presence of big ET-1, resulting in cell contraction and desensitization to further ET-1 stimulation; in situ hybridization analysis shows regional differences in ECE expression, suggesting that pulsatile production of endothelin by Sertoli cells (at specific "stages" of the seminiferous epithelium) may regulate the cyclicity of tubular contraction; when viewed in a scanning electron microscope, segments of seminiferous tubules containing the specific stages characterized by high expression of ECE were observed to contract in response to big ET-1, whereas stages with low ECE expression remained virtually unaffected. These data indicate that endothelin-mediated spatiotemporal control of rhythmic tubular contractility might be operated by Sertoli cells through the cyclic expression of ECE-1, which is, in turn, dependent upon the timing of spermatogenesis. 相似文献
53.
The reach-to-grasp movement in children with autism spectrum disorder 总被引:10,自引:0,他引:10
Mari M Castiello U Marks D Marraffa C Prior M 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2003,358(1430):393-403
Autism is associated with a wide and complex array of neurobehavioural symptoms. Examination of the motor system offers a particularly appealing method for studying autism by providing information about this syndrome that is relatively immune to experimental influence. In this article, we considered the relationship between possible movement disturbance and symptoms of autism and introduced an experimental model that may be useful for rehabilitation and diagnostic purposes: the reach-to-grasp movement. Research is reviewed that characterizes kinematically the reach-to-grasp movement in children with autism compared with age-matched 'controls'. Unlike the age-matched children, autistic children showed differences in movement planning and execution, supporting the view that movement disturbances may play a part in the phenomenon of autism. 相似文献
54.
Maria Molinos Morena F. Fiordalisi Joana Caldeira Catarina R. Almeida Mário A. Barbosa Raquel M. Gonçalves 《Aging cell》2023,22(8):e13873
Aging is one of the major etiological factors driving intervertebral disc (IVD) degeneration, the main cause of low back pain. The nucleus pulposus (NP) includes a heterogeneous cell population, which is still poorly characterized. Here, we aimed to uncover main alterations in NP cells with aging. For that, bovine coccygeal discs from young (12 months) and old (10–16 years old) animals were dissected and primary NP cells were isolated. Gene expression and proteomics of fresh NP cells were performed. NP cells were labelled with propidium iodide and analysed by flow cytometry for the expression of CD29, CD44, CD45, CD146, GD2, Tie2, CD34 and Stro-1. Morphological cell features were also dissected by imaging flow cytometry. Elder NP cells (up-regulated bIL-6 and bMMP1 gene expression) presented lower percentages of CD29+, CD44+, CD45+ and Tie2+ cells compared with young NP cells (upregulated bIL-8, bCOL2A1 and bACAN gene expression), while GD2, CD146, Stro-1 and CD34 expression were maintained with age. NP cellulome showed an upregulation of proteins related to endoplasmic reticulum (ER) and melanosome independently of age, whereas proteins upregulated in elder NP cells were also associated with glycosylation and disulfide bonds. Flow cytometry analysis of NP cells disclosed the existence of 4 subpopulations with distinct auto-fluorescence and size with different dynamics along aging. Regarding cell morphology, aging increases NP cell area, diameter and vesicles. These results contribute to a better understanding of NP cells aging and highlighting potential anti-aging targets that can help to mitigate age-related disc disease. 相似文献
55.
Daniele Bruno Aurora Montali Marzia Gariboldi Anna Katarzyna Wrońska Agata Kaczmarek Amr Mohamed Ling Tian Morena Casartelli Gianluca Tettamanti 《Insect Science》2023,30(4):912-932
In insects, the cell-mediated immune response involves an active role of hemocytes in phagocytosis, nodulation, and encapsulation. Although these processes have been well documented in multiple species belonging to different insect orders, information concerning the immune response, particularly the hemocyte types and their specific function in the black soldier fly Hermetia illucens, is still limited. This is a serious gap in knowledge given the high economic relevance of H. illucens larvae in waste management strategies and considering that the saprophagous feeding habits of this dipteran species have likely shaped its immune system to efficiently respond to infections. The present study represents the first detailed characterization of black soldier fly hemocytes and provides new insights into the cell-mediated immune response of this insect. In particular, in addition to prohemocytes, we identified five hemocyte types that mount the immune response in the larva, and analyzed their behavior, role, and morphofunctional changes in response to bacterial infection and injection of chromatographic beads. Our results demonstrate that the circulating phagocytes in black soldier fly larvae are plasmatocytes. These cells also take part in nodulation and encapsulation with granulocytes and lamellocyte-like cells, developing a starting core for nodule/capsule formation to remove/encapsulate large bacterial aggregates/pathogens from the hemolymph, respectively. These processes are supported by the release of melanin precursors from crystal cells and likely by mobilizing nutrient reserves in newly circulating adipohemocytes, which could thus trophically support other hemocytes during the immune response. Finally, the regulation of the cell-mediated immune response by eicosanoids was investigated. 相似文献
56.
A Oppenheim Z Sandalon A Peleg O Shaul S Nicolis S Ottolenghi 《Journal of virology》1992,66(9):5320-5328
Encapsidation of simian virus 40 is a complex biological process involving DNA-protein and protein-protein interactions in the formation of a unique three-dimensional structure around the viral minichromosome. A pseudoviral system developed in our laboratory, in which the viral early and late gene products are supplied in trans (by helpers), was used to analyze the encapsidation process independent of viral gene expression. With this experimental system we have discovered a requirement for a specific DNA signal for encapsidation, ses (for simian virus 40 encapsidation signal).ses is present within a 200-bp DNA fragment, which includes, in addition to the viral origin of replication (ori), six GGGCGG repeats (GC boxes) and 26 bp of the enhancer element. Deletion of the GC boxes and the enhancer sequences almost abolished encapsidation, while DNA replication was only moderately decreased. The ability to encapsidate was not regained by reinserting a DNA fragment carrying ses in the sesdeleted plasmid 2 kbp away from the ori, suggesting that for encapsidation the two DNA elements have to be close to each other. These findings afford novel strategies for the investigation of viral encapsidation. 相似文献
57.
Almost all about citrulline in mammals 总被引:2,自引:0,他引:2
Curis E Nicolis I Moinard C Osowska S Zerrouk N Bénazeth S Cynober L 《Amino acids》2005,29(3):177-205
Summary. Citrulline (Cit, C6H13N3O3), which is a ubiquitous amino acid in mammals, is strongly related to arginine. Citrulline metabolism in mammals is divided
into two fields: free citrulline and citrullinated proteins. Free citrulline metabolism involves three key enzymes: NO synthase
(NOS) and ornithine carbamoyltransferase (OCT) which produce citrulline, and argininosuccinate synthetase (ASS) that converts
it into argininosuccinate. The tissue distribution of these enzymes distinguishes three “orthogonal” metabolic pathways for
citrulline. Firstly, in the liver, citrulline is locally synthesized by OCT and metabolized by ASS for urea production. Secondly,
in most of the tissues producing NO, citrulline is recycled into arginine via ASS to increase arginine availability for NO
production. Thirdly, citrulline is synthesized in the gut from glutamine (with OCT), released into the blood and converted
back into arginine in the kidneys (by ASS); in this pathway, circulating citrulline is in fact a masked form of arginine to
avoid liver captation. Each of these pathways has related pathologies and, even more interestingly, citrulline could potentially
be used to monitor or treat some of these pathologies. Citrulline has long been administered in the treatment of inherited
urea cycle disorders, and recent studies suggest that citrulline may be used to control the production of NO. Recently, citrulline
was demonstrated as a potentially useful marker of short bowel function in a wide range of pathologies. One of the most promising
research directions deals with the administration of citrulline as a more efficient alternative to arginine, especially against
underlying splanchnic sequestration of amino acids. Protein citrullination results from post-translational modification of
arginine; that occurs mainly in keratinization-related proteins and myelins, and insufficiencies in this citrullination occur
in some auto-immune diseases such as rheumatoid arthritis, psoriasis or multiple sclerosis. 相似文献
58.
59.
This paper deals with information transfer from the environment and “self”-organization in open, nonlinear systems far from
thermodynamic equilibrium — in the presence of either non-stationary phase jitter noise, or amplitude stationary noise. By
“self”-organization we mean here the progressive formation within the system of sequential, ordered (coherent) relationships
between appropriate dynamical variables-like for example, the phase differences between the oscillating components of the
system. We take up (in Section II) the classical Laser as a specific example and examine in detail the influence of phase
jitter noise in the mode (phase) locking process. We find—as expected—that phase fluctuations in the cavity cause degradation
of the coherent behaviour (i.e. increase the entropy) of the system — which, however, levels off, or saturates with time.
Further (in Section III) we examine systems where the number of self-sustained oscillating components may vary with time in
such a way that the maximum entropy of the system increases faster than the overall instantaneous entropy. We put forth the
hypothesis that in such cases — because of the increase of the redundancy — the system gets organized not just in spite of,
but merely because of the presence of Noise. Possible applications in biological systems (especially concerning a model of
cerebral organization) are briefly discussed. It is understood here, that the system has to display some preliminary dynamical
structure before the organizing procedure takes over. What happens afterwards is the subject of this paper. 相似文献
60.
Javier Conde Morena Scotece Vanessa Abella Rodolfo Gómez Verónica López Rosa Villar Miguel Hermida Jesús Pino Juan Jesús Gómez-Reino Oreste Gualillo 《PloS one》2015,10(4)