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91.
Claudia Eichenberger Silke Oeljeklaus Julia Bruggisser Jan Mani Beat Haenni Iosif Kaurov Moritz Niemann Benoît Zuber Julius Luke Hassan Hashimi Bettina Warscheid Bernd Schimanski Andr Schneider 《Molecular microbiology》2019,112(6):1731-1743
The mitochondrial contact site and cristae organization system (MICOS) mediates the formation of cristae, invaginations in the mitochondrial inner membrane. The highly diverged MICOS complex of the parasitic protist Trypanosoma brucei consists of nine subunits. Except for two Mic10‐like and a Mic60‐like protein, all subunits are specific for kinetoplastids. Here, we determined on a proteome‐wide scale how ablation of individual MICOS subunits affects the levels of the other subunits. The results reveal co‐regulation of TbMic10‐1, TbMic10‐2, TbMic16 and TbMic60, suggesting that these nonessential, integral inner membrane proteins form an interdependent network. Moreover, the ablation of TbMic34 and TbMic32 reveals another network consisting of the essential, intermembrane space‐localized TbMic20, TbMic32, TbMic34 and TbMic40, all of which are peripherally associated with the inner membrane. The downregulation of TbMic20, TbMic32 and TbMic34 also interferes with mitochondrial protein import and reduces the size of the TbMic10‐containing complexes. Thus, the diverged MICOS of trypanosomes contains two subcomplexes: a nonessential membrane‐integrated one, organized around the conserved Mic10 and Mic60, that mediates cristae formation, and an essential membrane‐peripheral one consisting of four kinetoplastid‐specific subunits, that is required for import of intermembrane space proteins. 相似文献
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Availability of a suite of biomarkers for early detection, stratification into distinct subtypes, and monitoring progression or response to therapy promises significant improvements in clinical outcomes for cancer patients. However, despite the recent progress in proteomics technologies based on mass spectrometry (MS), discovery of novel clinical assessment tools has been slow. This is, partly due to the inherent difficulties in working with blood as the biospecimen for candidate discovery. A better understanding of the limitations of blood for comparative protein profiling and a better appreciation of the advantages of cancer tissue or cancer cell secretomes have the potential to greatly enhance the progress. 相似文献
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Invasive species often have reduced genetic diversity, but the opposite can be true if there have been multiple introductions and genetic admixture. Reduced diversity is most likely soon after establishment, in remote locations, when there is lower propagule pressure and with stepping-stone colonizations. The common house gecko (Hemidactylus frenatus) was introduced to Moorea, French Polynesia in the remote eastern Pacific within the last two decades and accordingly is expected to exhibit low diversity. In contrast, we show that H. frenatus on Moorea has exceptionally high genetic diversity, similar to that near the native range in Asia and much higher than reported for other Pacific island reptiles. The high diversity in this recently founded population likely reflects extensive genetic admixture in source population(s) and a life history that promotes retention of diversity. These observations point to the importance of understanding range-wide dynamics of genetic admixture in highly invasive species. 相似文献
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Motivated by recent experimental findings, we propose a novel mechanism of embryonic pattern formation based on coupling of tissue curvature with diffusive signaling by a chemical factor. We derive a new mathematical model using energy minimization approach and show that the model generates a variety of morphogen and curvature patterns agreeing with experimentally observed structures. The mechanism proposed transcends the classical Turing concept which requires interactions between two morphogens with a significantly different diffusivity. Our studies show how biomechanical forces may replace the elusive long-range inhibitor and lead to formation of stable spatially heterogeneous structures without existence of chemical prepatterns. We propose new experimental approaches to decisively test our central hypothesis that tissue curvature and morphogen expression are coupled in a positive feedback loop. 相似文献
98.
Matthias Schultze-Kraft Markus Diesmann Sonja Grün Moritz Helias 《PLoS computational biology》2013,9(4)
The functional significance of correlations between action potentials of neurons is still a matter of vivid debate. In particular, it is presently unclear how much synchrony is caused by afferent synchronized events and how much is intrinsic due to the connectivity structure of cortex. The available analytical approaches based on the diffusion approximation do not allow to model spike synchrony, preventing a thorough analysis. Here we theoretically investigate to what extent common synaptic afferents and synchronized inputs each contribute to correlated spiking on a fine temporal scale between pairs of neurons. We employ direct simulation and extend earlier analytical methods based on the diffusion approximation to pulse-coupling, allowing us to introduce precisely timed correlations in the spiking activity of the synaptic afferents. We investigate the transmission of correlated synaptic input currents by pairs of integrate-and-fire model neurons, so that the same input covariance can be realized by common inputs or by spiking synchrony. We identify two distinct regimes: In the limit of low correlation linear perturbation theory accurately determines the correlation transmission coefficient, which is typically smaller than unity, but increases sensitively even for weakly synchronous inputs. In the limit of high input correlation, in the presence of synchrony, a qualitatively new picture arises. As the non-linear neuronal response becomes dominant, the output correlation becomes higher than the total correlation in the input. This transmission coefficient larger unity is a direct consequence of non-linear neural processing in the presence of noise, elucidating how synchrony-coded signals benefit from these generic properties present in cortical networks. 相似文献
99.
Microhabitat partitioning in seagrass mesograzers is driven by consistent species choices across multiple predator and competitor contexts 下载免费PDF全文
Explanations for the coexistence of multiple species from the same functional group or taxonomic clade frequently include fine‐scale resource partitioning. However, despite the hypothesized importance of niche partitioning, we know relatively little about the underlying mechanisms. For example, differences in resource use may be fixed consequences of organism traits, or they may be achieved via context‐dependent behaviors. In this study we investigated mechanisms of microhabitat partitioning using eight species of marine mesograzers inhabiting seagrass and algae habitats, using laboratory trials to measure microhabitat use in the presence and absence of both predators and competitors. We found clear evidence for microhabitat partitioning between the species, which account for over 60% of the mesograzers commonly found in this system and vary in both body size and the ability to build tubes on habitat substrates. Species‐specific microhabitat use was poorly predicted by these two traits, but remained remarkably consistent across contexts. Habitat use was not affected by the presence of fish predators common in this system, even though predation pressure is thought to place strong constraints on microhabitat in communities of plant‐associated arthropods. The presence of competing species also did not affect the relative separation of microhabitat use. Behavioral responses to potential competitors did cause significant changes in microhabitat use in all of the smallest species, but these changes did not depend on competitor identity and were relatively small compared to among‐species patterns of microhabitat partitioning. The consistency of species‐specific microhabitat use, regardless of the presence of predators or competitors, should make coexistence most likely among species that differ in these choices. For these species, it appears that the benefits accrued from their selected microhabitats are not affected by species interactions, or that any benefits of alternative microhabitat use are outweighed by risks associated with movement. 相似文献