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1. Finding genes responsible for evolution of complex 3D leaf anatomy using tomographic microscopy

   Muir, CD; Bonnin A; Buckley TN; Conesa, MÀ; Galmés J; McKlin S; Rippner DA; Schmeltz M; Théroux-Rancourt G (January 2022, Botany)

   Traits in wild relatives of crop species can help breed sustainable crop varieties that produce more food with fewer resources. To make use of this variation, we need to find the genetic regions that allow wild species to use water and nutrients more efficiently. Leaf anatomy has a major effect on photosynthesis by determining rates of carbon gain and water loss. However, finding the genetic regions underlying leaf anatomical evolution has been limited by low-throughput and low-resolution trait measurements. 3D imaging using X-ray microcomputed tomography (μCT) may overcome these obstacles by providing high-throughput, high-resolution data on leaf anatomy. Compared to traditional 2D methods for leaf anatomy, 3D imaging captures physiologically important volumetric traits, is less biased, and encompasses a larger leaf area. We used synchrotron μCT to measure leaf anatomy on two tomato species Solanum lycopersicum (cultivated tomato) and S. pennellii (wild, drought-tolerant species), and four introgression lines containing loci that alter leaf anatomy. We measured stomatal density, size, and 3D arrangement, as well as leaf thickness and mesophyll porosity. Preliminary analyses show that synchrotron μCT can identify previously described quantitative trait loci for stomatal traits and leaf thickness and show how those traits are related to 3D leaf anatomy. We will use finite element models to show how these anatomical differences may contribute to genetic variation leaf CO2 and water vapour exchange. 

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2. Anatomy of the female reproductive tract organs of the brown anole ( Anolis sagrei )

   https://doi.org/10.1002/ar.25293  

   Kircher, Bonnie K.; Stanley, Edward L.; Behringer, Richard R. (July 2023, The Anatomical Record)

   Abstract Female reproduction in squamate reptiles (lizards and snakes) is highly diverse and mode of reproduction, clutch size, and reproductive tract morphology all vary widely across this group of ~11,000 species. Recently, CRISPR genome editing techniques that require manipulation of the female reproductive anatomy have been developed in this group, making a more complete understanding of this anatomy essential. We describe the adult female reproductive anatomy of the model reptile the brown anole ( Anolis sagrei ). We show that the brown anole female reproductive tract has three distinct anterior‐to‐posterior regions, the infundibulum, the glandular uterus, and the nonglandular uterus. The infundibulum has a highly ciliated epithelial lip, a region where the epithelium is inverted so that cilia are present on the inside and outside of the tube. The glandular uterus has epithelial ducts that are patent with a lumen as well as acinar structures with a lumen. The nonglandular uterus has a heterogeneous morphology from anterior to posterior, with a highly folded, ciliated epithelium transitioning to a stratified squamous epithelium. This transition is accompanied by a loss of keratin‐8 expression and together, these changes are similar to the morphological and gene expression changes that occur in the mammalian cervix. We recommend that description of the nonglandular uterus include the regional sub‐specification of a “cervix” and “vagina” as this terminology change more accurately describes the morphology. Our data extend histological studies of reproductive organ morphology in reptiles and expand our understanding of the variation in reproductive system anatomy across squamates and vertebrates. 

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3. The osteology of Shuvosaurus inexpectatus , a shuvosaurid pseudosuchian from the Upper Triassic Post Quarry, Dockum Group of Texas, USA

   https://doi.org/10.1002/ar.25376  

   Nesbitt, Sterling J; Chatterjee, Sankar (April 2024, The Anatomical Record)

   Abstract A vast array of pseudosuchian body plans evolved during the diversification of the group in the Triassic Period, but few can compare to the toothless, long‐necked, and bipedal shuvosaurids. Members of this clade possess theropod‐like character states mapped on top of more plesiomorphic pseudosuchian character states, complicating our understanding of the evolutionary history of the skeleton. One taxon in this clade,Shuvosaurus inexpectatushas been assigned to various theropod dinosaur groups based on a partial skull and referred material and its postcranium was assigned to a different taxon in Pseudosuchia. After the discovery of a skeleton of a shuvosaurid with aShuvosaurus‐like skull and a pseudosuchian postcranial skeleton, it became clearShuvosaurus inexpectatuswas a pseudosuchian. Nevertheless, a number of questions have arisen about what skeletal elements belonged toShuvosaurus inexpectatus, the identification of skull bones, and the resulting implication for pseudosuchian evolution. Here, we detail the anatomy of the skeletonShuvosaurus inexpectatusthrough a critical lens, parse out the bones that belong to the taxon or those that clearly do not or may not belong to the taxon, rediagnose the taxon based on these revisions, and compare the taxon to other archosaurs. We find thatShuvosaurus inexpectatuspossesses similar anatomy to other shuvosaurids but parts of the skeleton of the taxon clarifies the anatomy of the group given that they are preserved inShuvosaurus inexpectatusbut not in others.Shuvosaurus inexpectatusis represented by at least 14 individuals from the West Texas Post Quarry (Adamanian holochronozone) and allShuvosaurus inexpectatusskeletal material from the locality pertains to skeletally immature individuals. All of the skeletons are missing most of the neural arches, ribs, and most of the forelimb. We only recognizeShuvosaurus inexpectatusfrom the Post Quarry and all other material assigned to the taxon previously is better assigned to the broader group Shuvosauridae. 

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4. Eye structure shapes neuron function in Drosophila motion vision

   https://doi.org/10.1101/2022.12.14.520178  

   Zhao, Arthur; Gruntman, Eyal; Nern, Aljoscha; Iyer, Nirmala A; Rogers, Edward M; Koskela, Sanna; Siwanowicz, Igor; Dreher, Marisa; Flynn, Miriam A; Laughland, Connor W; et al (December 2022, bioRxiv)

   Summary Many animals rely on vision to navigate through their environment. The pattern of changes in the visual scene induced by self-motion is theoptic flow¹, which is first estimated in local patches by directionally selective (DS) neurons^2–4. But how should the arrays of DS neurons, each responsive to motion in a preferred direction at a specific retinal position, be organized to support robust decoding of optic flow by downstream circuits? Understanding this global organization is challenging because it requires mapping fine, local features of neurons across the animal’s field of view³. InDrosophila, the asymmetric dendrites of the T4 and T5 DS neurons establish their preferred direction, making it possible to predict DS responses from anatomy^4,5. Here we report that the preferred directions of fly DS neurons vary at different retinal positions and show that this spatial variation is established by the anatomy of the compound eye. To estimate the preferred directions across the visual field, we reconstructed hundreds of T4 neurons in a full brain EM volume⁶and discovered unexpectedly stereotypical dendritic arborizations that are independent of location. We then used whole-head μCT scans to map the viewing directions of all compound eye facets and found a non-uniform sampling of visual space that explains the spatial variation in preferred directions. Our findings show that the organization of preferred directions in the fly is largely determined by the compound eye, exposing an intimate and unexpected connection between the peripheral structure of the eye, functional properties of neurons deep in the brain, and the control of body movements. 

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5. Copper( i ) and silver( i ) chemistry of vinyltrifluoroborate supported by a bis(pyrazolyl)methane ligand

   https://doi.org/10.1039/d1dt00974e  

   Zacharias, Adway O.; Mao, James X.; Nam, Kwangho; Dias, H. V. (June 2021, Dalton Transactions)

   null (Ed.)

   Although unsaturated organotrifluoroborates are common synthons in metal–organic chemistry, their transition metal complexes have received little attention. [CH 2 (3,5-(CH 3 ) 2 Pz) 2 ]Cu(CH 2 CHBF 3 ), (SIPr)Cu(MeCN)(CH 2 CHBF 3 ) and [CH 2 (3,5-(CH 3 ) 2 Pz) 2 ]Ag(CH 2 CHBF 3 ) represent rare, isolable molecules featuring a vinyltrifluoroborate ligand on coinage metals. The X-ray crystal structures show the presence of three-coordinate metal sites in these complexes. The vinyltrifluoroborate group binds asymmetrically to the metal site in [CH 2 (3,5-(CH 3 ) 2 Pz) 2 ]M(CH 2 CHBF 3 ) (M = Cu, Ag) with relatively closer M–C(H) 2 distances. The computed structures of [CH 2 (3,5-(CH 3 ) 2 Pz) 2 ]M(CH 2 CHBF 3 ) and M(CH 2 CHBF 3 ), however, have shorter M–C(H)BF 3 distances than M–C(H) 2 . These molecules feature various inter- or intra-molecular contacts involving fluorine of the BF 3 group, possibly affecting these M–C distances. The binding energies of [CH 2 CHBF 3 ] − to Cu + , Ag + and Au + have been calculated at the wB97XD/def2-TZVP level of theory, in the presence and absence of the supporting ligand CH 2 (3,5-(CH 3 ) 2 Pz) 2 . The calculation shows that Au + has the strongest binding to the [CH 2 CHBF 3 ] − ligand, followed by Cu + and Ag + , irrespective of the presence of the supporting ligand. However, in all three metals, the supporting ligand weakens the binding of olefin to the metal. The same trends were also found from the analysis of the σ-donation and π-backbonding interactions between the metal fragment and the π and π* orbitals of [CH 2 CHBF 3 ] − . 

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