共查询到20条相似文献,搜索用时 15 毫秒
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Mitochondria play an important role in the progression of apoptosis through the release of pro-apoptotic factors, such as cytochrome c, from the mitochondrial intermembrane space. During this process, mitochondrial networks are dramatically reorganised from long filamentous interconnected tubules into small punctate spheres. Whether remodelling of mitochondrial networks is necessary for apoptosis-associated cytochrome c release, or merely an accompanying process, has been a subject of debate. Here we discuss evidence for and against the role of mitochondrial fragmentation in the progression of apoptosis and highlight recent advances which indicate that mitochondrial fission is not a critical requirement for apoptosis-associated cytochrome c release. We also discuss an emerging role for Bcl-2 family members as regulators of mitochondrial fission and fusion dynamics, independent of the role of this family in the regulation of apoptosis. 相似文献
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Motion: the long and short of it 总被引:6,自引:0,他引:6
Several authors have proposed that motion is analyzed by two separate processes: short-range and long-range. We claim that the differences between short-range and long-range motion phenomena are a direct consequence of the stimuli used in the two paradigms and are not evidence for the existence of two qualitatively different motion processes. We propose that a single style of motion analysis, similar to the well known Reichardt and Marr-Ullman motion detectors, underlies all motion phenomena. Although there are different detectors of this type specialized for different visual attributes (namely first-order and second-order stimuli), they all share the same mode of operation. We review the studies of second-order motion stimuli to show that they share the basic phenomena observed for first-order stimuli. The similarity across stimulus types suggests, not parallel streams of motion extraction, one short-range and passive and the other long-range and intelligent, but a concatenation of a common mode of initial motion extraction followed by a general inference process. 相似文献
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Stereocilia: the long and the short of it 总被引:2,自引:0,他引:2
Belyantseva IA Labay V Boger ET Griffith AJ Friedman TB 《Trends in molecular medicine》2003,9(11):458-461
Mutations in whirlin, a putative PDZ scaffold protein, have recently been shown to cause deafness and short cochlear hair cell stereocilia in whirler mice and recessive deafness (DFNB31) in humans. Through its PDZ domains, whirlin might organize a group of proteins into a functional complex required for stereocilia elongation. Identifying these protein partners will advance our understanding of the development of stereocilia and their function as mechanosensory organelles indispensable for normal hearing. 相似文献
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Thompson MV 《Trends in plant science》2006,11(1):26-32
The structure of phloem sieve-element-companion-cell complexes reflects a duality of function: to conduct photoassimilates throughout the plant, and to exchange solutes between the phloem and surrounding tissues. The conceptual integration of these long- and short-distance functions requires the abandonment of a long-cherished concept in phloem physicochemistry, that source-sink turgor differentials control flow. The manifest inability of decentralized organisms such as plants to control phloem translocation centrally disqualifies such differentials as control variables; besides, the phloem is maximally efficient if the pressure differentials are small. Testing this hypothesis and whether turgor differentials are small will require a significant recommitment to studying the quantitative anatomy of phloem. 相似文献
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Olfactory memory: the long and short of it 总被引:2,自引:2,他引:0
It has been proposed that memory for odors does not have a short-term (or
working) memory system. The distinction between short- and long- term
memory in other sensory modalities has been generally supported by three
main lines of evidence: capacity differences between the proposed systems,
evidence of differential coding, and differential memory losses in
neuropsychological patients. The present paper examines these issues in an
effort to establish a similar distinction for the memory of olfactory
stimuli. Each of these lines of evidence is examined in relation to the
literature on olfactory memory. Based on this examination, it seems that
there is at least preliminary support from each of these lines of evidence
to advocate a distinction between a long- and short-term memory for
olfactory stimuli. Emphasis is placed upon the qualitative similarity of
olfactory memory to other memory systems. This similarity is further
highlighted through an examination of the literature pertinent to serial
position effects in memory for olfactory stimuli.
相似文献
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Mitochondrial outer membrane permeabilization (MOMP) determines the point-of-no-return of most if not all signal-transduction cascades leading to cell death. It has been postulated that the molecular mechanism leading to MOMP could depend on the activation of the mitochondrial fission machinery mediated by proteins from the dynamin superfamily. However, recent work suggests that, depending on the specific apoptosis induction pathway, mitochondrial fission can occur independently or downstream from MOMP. Moreover, fragmentation of the mitochondrial network can inhibit MOMP and apoptosis in response to a particular range of lethal stimuli, namely those relying on Ca(2+) waves. Failure to transmit the Ca(2+) wave through disconnected mitochondria then interrupts the propagation of the pro-apoptotic signal. Thus, mitochondrial fission can either enhance or reduce the probability of MOMP and consequent cell death, depending on the initial lethal stimulus. 相似文献
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Holbrook SR 《Current opinion in structural biology》2005,15(3):302-308
The database of RNA structure has grown tremendously since the crystal structure analyses of ribosomal subunits in 2000-2001. During the past year, the trend toward determining the structure of large, complex biological RNAs has accelerated, with the analysis of three intact group I introns, A- and B-type ribonuclease P RNAs, a riboswitch-substrate complex and other structures. The growing database of RNA structures, coupled with efforts directed at the standardization of nomenclature and classification of motifs, has resulted in the identification and characterization of numerous RNA secondary and tertiary structure motifs. Because a large proportion of RNA structure can now be shown to be composed of these recurring structural motifs, a view of RNA as a modular structure built from a combination of these building blocks and tertiary linkers is beginning to emerge. At the same time, however, more detailed analysis of water, metal, ligand and protein binding to RNA is revealing the effect of these moieties on folding and structure formation. The balance between the views of RNA structure either as strictly a construct of preformed building blocks linked in a limited number of ways or as a flexible polymer assuming a global fold influenced by its environment will be the focus of current and future RNA structural biology. 相似文献
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《Nature medicine》2007,13(11):1265
It can take twice as long to get a PhD in biomedical sciences in the US as it does in other countries such as the UK and Australia. Are US PhDs worth more, or are there advantages to a speedier system? 相似文献
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Kai J. Rogers Rahul Vijay Noah S. Butler 《Microbes and infection / Institut Pasteur》2021,23(4-5):104807
Humoral immunity is critical for limiting Plasmodium parasite infections and the severity of malaria. Naturally acquired immunity against malaria occurs inefficiently and protection is relatively short-lived. Here we review recent advances and explore emerging hypotheses regarding the molecular and cellular pathways that regulate Plasmodium parasite-specific B cell responses and durable anti-malarial humoral immunity. 相似文献
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Mitochondrial fusion and fission in cell life and death 总被引:1,自引:0,他引:1
Westermann B 《Nature reviews. Molecular cell biology》2010,11(12):872-884
Mitochondria are dynamic organelles that constantly fuse and divide. These processes (collectively termed mitochondrial dynamics) are important for mitochondrial inheritance and for the maintenance of mitochondrial functions. The core components of the evolutionarily conserved fusion and fission machineries have now been identified, and mechanistic studies have revealed the first secrets of the complex processes that govern fusion and fission of a double membrane-bound organelle. Mitochondrial dynamics was recently recognized as an important constituent of cellular quality control. Defects have detrimental consequences on bioenergetic supply and contribute to the pathogenesis of neurodegenerative diseases. These findings open exciting new directions to explore mitochondrial biology. 相似文献
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Axonal transport of microtubules: the long and short of it 总被引:3,自引:0,他引:3
Recent studies on cultured neurons have demonstrated that microtubules are transported down the axon in the form of short polymers. The transport of these microtubules is bidirectional, intermittent, asynchronous, and occurs at the fast rate of known motors. The majority of the microtubule mass in the axon exists in the form of longer immobile microtubules. We have proposed a model called 'cut and run', in which the longer microtubules are mobilized by enzymes that sever them into shorter mobile polymers. In this view, the molecular motors that transport microtubules are not selective for short microtubules but rather impinge upon microtubules irrespective of their length. In the case of the longer microtubules, these motor-driven forces do not transport the microtubules in a rapid and concerted fashion but presumably affect them nonetheless. Here, we discuss the mechanisms by which the short microtubules are transported and suggest possibilities for how analogous mechanisms may align and organize the longer microtubules and functionally integrate them with each other and with the actin cytoskeleton. 相似文献
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Lindsey K 《Current biology : CB》2001,11(18):R741-R743
A polypeptide from tobacco has been found to be processed into multiple functional peptides, each with independent hormone-like activities. This adds to a growing set of small peptides known to function as signal molecules in plants. 相似文献
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