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Mitochondria generate ATP and play regulatory roles in various cellular activities. Cancer cells often exhibit fragmented mitochondria. However, the underlying mechanism remains elusive. Here we report that a mitochondrial protein FUN14 domain containing 2 (FUNDC2) is transcriptionally upregulated in primary mouse liver tumors, and in approximately 40% of human hepatocellular carcinoma (HCC). Importantly, elevated FUNDC2 expression inversely correlates with patient survival, and its knockdown inhibits liver tumorigenesis in mice. Mechanistically, the amino-terminal region of FUNDC2 interacts with the GTPase domain of mitofusin 1 (MFN1), thus inhibits its activity in promoting fusion of outer mitochondrial membrane. As a result, loss of FUNDC2 leads to mitochondrial elongation, decreased mitochondrial respiration, and reprogrammed cellular metabolism. These results identified a mechanism of mitochondrial fragmentation in cancer through MFN1 inhibition by FUNDC2, and suggested FUNDC2 as a potential therapeutic target of HCC. Fragmented mitochondria are a frequent hallmark of cancer, but the cause and consequence are less clear. The authors demonstrate that elevated FUNDC2 causes mitochondrial fragmentation through inhibition of MFN1 in hepatocellular carcinoma and that knockdown of FUNDC2 inhibits liver tumorigenesis in mice. [ABSTRACT FROM AUTHOR]

Coral reef ecosystems support significant biological activities and harbor huge diversity, but they are facing a severe crisis driven by anthropogenic activities and climate change. An important behavioral trait of the coral holobiont is coral motion, which may play an essential role in feeding, competition, reproduction, and thus survival and fitness. Therefore, characterizing coral behavior through motion analysis will aid our understanding of basic biological and physical coral functions. However, tissue motion in the stony scleractinian corals that contribute most to coral reef construction are subtle and may be imperceptible to both the human eye and commonly used imaging techniques. Here we propose and apply a systematic approach to quantify and visualize subtle coral motion across a series of light and dark cycles in the scleractinian coral Montipora capricornis. We use digital image correlation and optical flow techniques to quantify and characterize minute coral motions under different light conditions. In addition, as a visualization tool, motion magnification algorithm magnifies coral motions in different frequencies, which explicitly displays the distinctive dynamic modes of coral movement. Specifically, our assessment of displacement, strain, optical flow, and mode shape quantify coral motion under different light conditions, and they all show that M. capricornis exhibits more active motions at night compared to day. Our approach provides an unprecedented insight into micro-scale coral movement and behavior through macro-scale digital imaging, thus offering a useful empirical toolset for the coral research community. [ABSTRACT FROM AUTHOR]

Background: Schima genus of Theaceae is confined to subtropics and tropics of South, East and Southeast Asia. Thirteen species of Schima are distributed in subtropical China. Many of them appear as dominant canopy species in the subtropical forests. To date, Schima species richness distribution patterns of China have remained unknown. Meanwhile, there has been a longtime debate as to whether forests dominated by Schima species are early or late successional forests. We aim to clarify Schima species richness patterns and these species' roles in the forest succession and regeneration dynamics of the subtropical ecosystem in Yunnan Province, China. Method: We mapped Schima species richness distribution patterns in China. Based on 71 vegetation plots, we analyzed forest characteristics, population structure, and regeneration dynamics of Schima species in Yunnan. Results: Yunnan was found to harbor the greatest richness and the highest rarity-weighted richness of Schima species in the subtropical regions of China. We classified five primary and six secondary forest types containing Schima species as one of dominants. Yunnan had the high floristic diversity and varying stand structure of forests containing Schima species. The Schima species studied generally had a sporadic regeneration type and a long life-span. Four species (Schima argentea, Schima villosa, Schima sinensis, Schima sericans) were shade-intolerant. But three species (Schima noronhae, Schima khasiana and Schima wallichii) were considered as bi-modal type species having shade-intolerant and shade-tolerant traits. Schima noronhae was seen to be a top dominant in late successional forests, while S. wallichii was found as a top-dominant in early or middle or late successional forests. S. khasiana, Schima villosa, Schima sinensis usually appeared as a top dominant in early or middle successional secondary forests, though they also presented as a second dominant in late-successional forests. Schima argentea and Schima sericans dominated only in the early or middle/seral successional forests. Schima species' regeneration establishment depended mainly on forest canopy gap formation through moderate human and natural disturbances. Conclusions: Yunnan has high species richness and rarity-weighted richness of Schima. Both moderate human and natural disturbances have provided regeneration niches for Schima species. Some of the Schima species studied as a second dominant (rare as the top-dominant) present in the late-successional forests. Some of them are more often as the top-dominant in early or middle successional forests, where as time goes by the dominance of Schima species would be replaced by their associated dominant taxa such as Castanopsis species. [ABSTRACT FROM AUTHOR]

Background: The impacts of selective logging on ecosystem multifunctionality (EMF) remain largely unexplored. In this study, we analyzed the response of nine variables related to four ecosystem functions (i.e. nutrient cycling, soil carbon stocks, decomposition, and wood production) to five selective logging intensities in a Pinus yunnanensis-dominated forest. We included a control group with no harvest to evaluate the potential shifts in EMF of the P. yunnanensis forests. We also assessed the relationship between above- and belowground biodiversity and EMF under these different selective logging intensities. Additionally, we evaluated the effects of biotic and abiotic factors on EMF using a structural equation modeling (SEM) approach. Results: Individual ecosystem functions (EFs) all had a significant positive correlation with selective logging intensity. Different EFs showed different patterns with the increase of selective logging intensity. We found that EMF tended to increase with logging intensity, and that EMF significantly improved when the stand was harvested at least twice. Both functional diversity and soil moisture had a significant positive correlation with EMF, but soil fungal operational taxonomic units (OTUs) had a significant negative correlation with EMF. Based on SEM, we found that selective logging improved EMF mainly by increasing functional diversity. Conclusion: Our study demonstrates that selective logging is a good management technique from an EMF perspective, and thus provide us with potential guidelines to improve forest management in P. yunnanensis forests in this region. The functional diversity is maximized through reasonable selective logging measures, so as to enhance EMF. [ABSTRACT FROM AUTHOR]

It is essential to understand how the loss of biodiversity impacts both ecosystem function (EF) and multifunctionality (EMF). Previous studies have mostly focused on predicting how species richness (SR) impacts EMF, while the effect of functional diversity (FD) on EMF remains unclear. Specifically, we know little about the primary functional drivers impacting EMF compared with SR. Therefore, we analysed 8 ecosystem functions within 58 natural secondary forest plots to investigate the effect of FD on both individual EF and EMF. Our results suggest that SR and FD had very significant positive effects on plant phosphorus, soil available phosphorus, and soil total nitrogen. FD explained significantly more variations in these functional responses than SR for individual ecosystem functioning. We also used a multiple threshold approach to test the effect of SR and FD on EMF. We found that FD and SR were positively related to EMF regardless of whether low-level function or high-level function was desired, but FD had a larger effect than SR. Based on the averaging approach, OLS regression, multivariate linear regression model and random forest analysis, we found that SR and FD were both drivers of EMF but that FD had a stronger effect and could explain more variation. As such, we conclude that FD drives ecosystem multifunctionality more than SR. [ABSTRACT FROM AUTHOR]