Structural color is poorly known in plants relative to animals. In fruits, only a handful of cases have been described, including in We obtained fresh and herbarium fruit material from 30 We identify at least two (possibly three) origins of blue fruit color in Examining the full spectrum of mechanisms producing color in pl, including structural color as well as pigments, will yield further insights into the diversity, ecology, and evolution of fruit color.
The majority of plant colours are produced by anthocyanin and carotenoid pigments, but colouration obtained by nanostructured materials (i.e. structural colours) is increasingly reported in plants. Here, we identify a multilayer photonic structure in the fruits of We used a combination of transmission electron microscopy (EM), serial EM tomography, scanning force microscopy and optical simulations to characterise the photonic structure in We found that the structural colour derives from a disordered, multilayered reflector consisting of lipid droplets of
- Award ID(s):
- 1553114
- NSF-PAR ID:
- 10445217
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 235
- Issue:
- 3
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 898-906
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary Viburnum tinus where the blue color results from a disordered multilayered reflector made of lipid droplets. Here, we examine the broader evolutionary context of fruit structural color across the genusViburnum .Viburnum species spanning the phylogeny and used transmission electron microscopy, optical simulations, and ancestral state reconstruction to identify the presence/absence of photonic structures in each species, understand the mechanism producing structural color in newly identified species, relate the development of cell wall structure to reflectance inViburnum dentatum , and describe the evolution of cell wall architecture acrossViburnum .Viburnum in species which produce large photonic structures made of lipid droplets embedded in the cell wall and which reflect blue light. -
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Key points Gap junctions formed by different connexins are expressed throughout the body and harbour unique channel properties that have not been fully defined mechanistically.
Recent structural studies by cryo‐electron microscopy have produced high‐resolution models of the related but functionally distinct lens connexins (Cx50 and Cx46) captured in a stable open state, opening the door for structure–function comparison.
Here, we conducted comparative molecular dynamics simulation and electrophysiology studies to dissect the isoform‐specific differences in Cx46 and Cx50 intercellular channel function.
We show that key determinants Cx46 and Cx50 gap junction channel open stability and unitary conductance are shaped by structural and dynamic features of their N‐terminal domains, in particular the residue at the 9th position and differences in hydrophobic anchoring sites.
The results of this study establish the open state Cx46/50 structural models as archetypes for structure–function studies targeted at elucidating the mechanism of gap junction channels and the molecular basis of disease‐causing variants.
Abstract Connexins form intercellular communication channels, known as gap junctions (GJs), that facilitate diverse physiological roles, from long‐range electrical and chemical coupling to coordinating development and nutrient exchange. GJs formed by different connexin isoforms harbour unique channel properties that have not been fully defined mechanistically. Recent structural studies on Cx46 and Cx50 defined a novel and stable open state and implicated the amino‐terminal (NT) domain as a major contributor for isoform‐specific functional differences between these closely related lens connexins. To better understand these differences, we constructed models corresponding to wildtype Cx50 and Cx46 GJs, NT domain swapped chimeras, and point variants at the 9th residue for comparative molecular dynamics (MD) simulation and electrophysiology studies. All constructs formed functional GJ channels, except the chimeric Cx46‐50NT variant, which correlated with an introduced steric clash and increased dynamical behaviour (instability) of the NT domain observed by MD simulation. Single channel conductance correlated well with free‐energy landscapes predicted by MD, but resulted in a surprisingly greater degree of effect. Additionally, we observed significant effects on transjunctional voltage‐dependent gating (
V jgating) and/or open state dwell times induced by the designed NT domain variants. Together, these studies indicate intra‐ and inter‐subunit interactions involving both hydrophobic and charged residues within the NT domains of Cx46 and Cx50 play important roles in defining GJ open state stability and single channel conductance, and establish the open state Cx46/50 structural models as archetypes for structure–function studies targeted at elucidating GJ channel mechanisms and the molecular basis of cataract‐linked connexin variants. -
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Abstract Pioneer trees with fleshy fruits are typically planted in restoration projects to attract frugivores as a mean to increase dispersal and accelerate forest regeneration. However, differences in fruit traits of pioneer trees can potentially influence dispersal and their restoration outcomes.
Here we investigated the effects of bird and plant traits, and distance to forest fragments, on the seed rain using a tree‐planting experiment replicated in 12 deforested sites in Brazil. Factors were fruit traits of pioneer trees (wind‐dispersed, bird‐dispersed with lipids or with carbohydrates and controls) and distance (10, 50, 300 m) from forest fragments.
We found that density and richness of birds and seeds decreased exponentially with distance from fragments, yet these effects were minor compared to the effects of fruit traits on the structure of the seed rain.
Overall, plots with fleshy fruited pioneers attracted much greater bird activity and seed dispersal than plots with wind‐dispersal pioneers and the controls. For instance, plots with carbohydrate‐rich fruits received more than twice the average species richness and density of birds and seeds of plots with lipid‐rich pioneer trees, surpassing wind‐dispersed pioneers by more than 80%, and controls by over 90%. Furthermore, the fruit trait treatments resulted in morphological shifts in the average traits of visiting birds. Significant differences in bill gape and flight capacities (wing‐loading) were associated with the differences in the seed rain associated with each treatment.
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Abstract Cryo‐electron microscopy (cryo‐EM) has become a major experimental technique to determine the structures of large protein complexes and molecular assemblies, as evidenced by the 2017 Nobel Prize. Although cryo‐EM has been drastically improved to generate high‐resolution three‐dimensional maps that contain detailed structural information about macromolecules, the computational methods for using the data to automatically build structure models are lagging far behind. The traditional cryo‐EM model building approach is template‐based homology modeling. Manual de novo modeling is very time‐consuming when no template model is found in the database. In recent years, de novo cryo‐EM modeling using machine learning (ML) and deep learning (DL) has ranked among the top‐performing methods in macromolecular structure modeling. DL‐based de novo cryo‐EM modeling is an important application of artificial intelligence, with impressive results and great potential for the next generation of molecular biomedicine. Accordingly, we systematically review the representative ML/DL‐based de novo cryo‐EM modeling methods. Their significances are discussed from both practical and methodological viewpoints. We also briefly describe the background of cryo‐EM data processing workflow. Overall, this review provides an introductory guide to modern research on artificial intelligence for de novo molecular structure modeling and future directions in this emerging field.
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Structure and Mechanism > Molecular Structures
Structure and Mechanism > Computational Biochemistry and Biophysics
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Abstract Floral structures, such as stamen appendages, play crucial roles in pollinator attraction, pollen release dynamics and, ultimately, the reproductive success of plants. The pollen‐rewarding, bee buzz‐pollinated flowers of
Melastomataceae often bear conspicuous staminal appendages. Surprisingly, their functional role in the pollination process remains largely unclear. We useHuberia bradeana Bochorny & R. Goldenb. (Melastomataceae ) with conspicuously elongated, twisted stamen appendages to investigate their functional role in the pollination process.We studied the effect of stamen appendages on pollinator behaviour and reproductive success by comparing manipulated flowers (appendages removed) with unmanipulated flowers. To assess bee pollinator behaviour, we measured three properties of buzzes (vibrations) produced by bees on
Huberia flowers: frequency, duration and number of buzzes per flower visit. We measured male and female reproductive success by monitoring pollen release and deposition after single bee visits. Finally, we used artificial vibrations and laser vibrometry to assess how flower vibrational properties change with the removal of stamen appendages.Our results show that the absence of staminal appendages does not modify bee buzzing behaviour. Pollen release was higher in unmanipulated flowers, but stigmatic pollen loads differ only marginally between the two treatments. We also detected lower vibration amplitudes in intact flowers as compared to manipulated flowers in artificial vibration experiments.
The presence of connective appendages are crucial in transmitting vibrations and assuring optimal pollen release. Therefore, we propose that the high diversity of colours, shapes and sizes of connective appendages in buzz‐pollinated flowers may have evolved by selection through male fitness.
