Cytoskeletal dynamics of gamete nuclear migration in flowering plants, animals, and yeast.

Gamete nuclear migration is a critical process during fertilization in flowering plants, yet its molecular mechanisms remain poorly understood. Recent studies have highlighted the essential role of cytoskeletal elements, particularly F-actin, in directing sperm nuclear migration, which differ from the microtubule-driven migration in animals. We summarize the process of sperm nuclear migration in plants and the involvement of Class XI myosin XI-G in Arabidopsis, along with the ROP8-SCAR2 pathway's ARP2/3-independent mechanism for F-actin nucleation.

"The PO-Driven Model": A Basic Science Pipeline for the Bioeconomy with Solutions Inspired by Convergent Evolution for Connecting Parallel Research Ideas.

Basic science research, also called "curiosity-driven research," is fundamental work done with no immediate economic goals but rather a focus on discovery for discovery's sake. However, basic science research is often needed to seed more applied, economically oriented, research. Both basic and applied research efforts are important aspects of the "bioeconomy," defined here as the contributions to the overall economy from various biology-related fields spanning everything from museum-based natural history research to agricultural food and material production to healthcare.

Dehydrin Client Proteins Identified Using Phage Display Affinity Selected Libraries Processed With Paired-End Phage Sequencing.

The late embryogenesis abundant proteins (LEAPs) are a class of noncatalytic, intrinsically disordered proteins with a malleable structure. Some LEAPs exhibit a protein and/or membrane binding capacity and LEAP binding to various targets has been positively correlated with abiotic stress tolerance. Regarding the LEAPs' presumptive role in protein protection, identifying client proteins (CtPs) to which LEAPs bind is one practicable means of revealing the mechanism by which they exert their function.

Insights into dynamic coenocytic endosperm development: Unraveling molecular, cellular, and growth complexity.

The endosperm, a product of double fertilization, is one of the keys to the evolution and success of angiosperms in conquering the land. While there are differences in endosperm development among flowering plants, the most common form is coenocytic growth, where the endosperm initially undergoes nuclear division without cytokinesis and eventually becomes cellularized. This complex process requires interplay among networks of transcription factors such as MADS-box, auxin response factors (ARFs), and phytohormones.

Evidence of a novel silencing effect on transgenes in the Arabidopsis thaliana sperm cell.

We encountered unexpected transgene silencing in Arabidopsis thaliana sperm cells; transgenes encoding proteins with no specific intracellular localization (cytoplasmic proteins) were silenced transcriptionally or posttranscriptionally. The mRNA of cytoplasmic protein transgenes tagged with a fluorescent protein gene was significantly reduced, resulting in undetectable fluorescent protein signals in the sperm cell. Silencing of the cytoplasmic protein transgenes in the sperm cell did not affect the expression of either its endogenous homologous genes or cotransformed transgenes encoding a protein with targeted intracellular localization.

Prominent caudal shift of the lumbar plexus roots in spines with 18 thoracolumbar vertebrae.

Purpose: It remains unclear whether concomitant changes in the thoracolumbar (TL) vertebrae and lumbar plexus roots seen in experimental embryology are present in humans with different vertebral formulas, particularly in humans with 18 TL vertebrae. We thus investigated the human lumbar plexus root changes occurring in spines with an additional TL vertebra (18TL).

Methods: The lumbosacral plexus was macroscopically dissected in TL anomaly cases found in 161 computed tomography examinations.

Cellular dynamics of coenocytic endosperm development in Arabidopsis thaliana.

After double fertilization, the endosperm in the seeds of many flowering plants undergoes repeated mitotic nuclear divisions without cytokinesis, resulting in a large coenocytic endosperm that then cellularizes. Growth during the coenocytic phase is strongly associated with the final seed size; however, a detailed description of the cellular dynamics controlling the unique coenocytic development in flowering plants has remained elusive. By integrating confocal microscopy live-cell imaging and genetics, we have characterized the entire development of the coenocytic endosperm of Arabidopsis thaliana including nuclear divisions, their timing intervals, nuclear movement and cytoskeleton dynamics.

F-actin regulates the polarized secretion of pollen tube attractants in Arabidopsis synergid cells.

Pollen tube attraction is a key event of sexual reproduction in flowering plants. In the ovule, two synergid cells neighboring the egg cell control pollen tube arrival via the active secretion of attractant peptides such as AtLURE1 and XIUQIU from the filiform apparatus (FA) facing toward the micropyle. Distinctive cell polarity together with longitudinal F-actin and microtubules are hallmarks of the synergid cell in various species, though the functions of these cellular structures are unclear.

Live-cell imaging reveals the cellular dynamics in seed development.

Seed development in flowering plants is highly complex and governed by three genetically distinct tissues: the fertilization products, the diploid embryo and triploid endosperm, as well as the seed coat that has maternal origin. There are diverse cellular dynamics such as nuclear movement in gamete cells for fertilization, cell polarity establishment for embryo development, and multinuclear endosperm formation. These tissues also coordinate and synchronize the developmental timing for proper seed formation through cell-to-cell communications.

Effect of assimilate competition during early seed development on the pod and seed growth traits in soybean.

Although the seed remains small in size during the initial stage of seed development (the lag phase), several studies indicate that environment and assimilate supply level manipulations during the lag phase affect the final seed size. However, the manipulations were not only at the lag phase, making it difficult to understand the specific role of the lag phase in final seed size determination. It also remained unclear whether environmental cues are sensed by plants and regulate seed development or if it is simply the assimilate supply level, changed by the environment, that affects the subsequent seed development.

Integrated anatomical practice combining cadaver dissection and matched cadaver CT data processing and analysis.

Purpose: With the increasing significance of diagnostic imaging in clinical practice, long-term anatomical education and training is required to ensure that students can reliably distinguish anatomical structures and interpret images. To improve students' motivation and prospects for learning imaging anatomy, we developed an integrated anatomical practice program combining cadaveric dissection with cadaver CT data processing and analysis during undergraduate students' dissection courses.

Methods: Workstations imported with post-mortem CT data of dissected cadavers and various forms of clinical CT/MRI data were set in the dissection room.

Comparative transcriptomic analysis reveals conserved programmes underpinning organogenesis and reproduction in land plants.

The appearance of plant organs mediated the explosive radiation of land plants, which shaped the biosphere and allowed the establishment of terrestrial animal life. The evolution of organs and immobile gametes required the coordinated acquisition of novel gene functions, the co-option of existing genes and the development of novel regulatory programmes. However, no large-scale analyses of genomic and transcriptomic data have been performed for land plants.

Insights into the molecular evolution of fertilization mechanism in land plants.

Comparative genetics and genomics among green plants, including algae, provide deep insights into the evolution of land plant sexual reproduction. Land plants have evolved successive changes during their conquest of the land and innovations in sexual reproduction have played a major role in their terrestrialization. Recent years have seen many revealing dissections of the molecular mechanisms of sexual reproduction and much new genomics data from the land plant lineage, including early diverging land plants, as well as algae.

Formins control dynamics of F-actin in the central cell of .

In the female gamete of flowering plants, sperm nuclear migration is controlled by a constant inward movement of actin filaments (F-actin) for successful fertilization. This dynamic F-actin movement is ARP2/3-independent, raising the question of how actin nucleation and polymerization is controlled in the female gamete. Using confocal microscopy live-cell imaging in combination with a pharmacological approach, we assessed the involvement of another group of actin nucleators, formins, in F-actin inward movement in the central cell of .

First in situ 3D visualization of the human cardiac conduction system and its transformation associated with heart contour and inclination.

Current advanced imaging modalities with applied tracing and processing techniques provide excellent visualization of almost all human internal structures in situ; however, the actual 3D internal arrangement of the human cardiac conduction system (CCS) is still unknown. This study is the first to document the successful 3D visualization of the CCS from the sinus node to the bundle branches within the human body, based on our specialized physical micro-dissection and its CT imaging. The 3D CCS transformation by cardiac inclination changes from the standing to the lying position is also provided.

Postmortem evaluation of neuromuscular damages more extensive than the surgical intervention area after iliac crest bone graft.

Several complications may occur following iliac bone grafting, one of the common sites for autologous bone harvesting. Of these, it is difficult to localize the damage in neurological complications due to the presence of several nerves in a similar distribution area with variations among individuals. To minimize these complications, conventional clinical anatomical studies using normal human cadavers have estimated the theoretical neurological damage area corresponding to the surgical intervention area.

ARP2/3-independent WAVE/SCAR pathway and class XI myosin control sperm nuclear migration in flowering plants.

After eukaryotic fertilization, gamete nuclei migrate to fuse parental genomes in order to initiate development of the next generation. In most animals, microtubules control female and male pronuclear migration in the zygote. Flowering plants, on the other hand, have evolved actin filament (F-actin)-based sperm nuclear migration systems for karyogamy.

Cellular dynamics of double fertilization and early embryogenesis in flowering plants.

Flowering plants (angiosperms) perform a unique double fertilization in which two sperm cells fuse with two female gamete cells in the embryo sac to develop a seed. Furthermore, during land plant evolution, the mode of sexual reproduction has been modified dramatically from motile sperm in the early-diverging land plants, such as mosses and ferns as well as some gymnosperms (Ginkgo and cycads) to nonmotile sperm that are delivered to female gametes by the pollen tube in flowering plants. Recent studies have revealed the cellular dynamics and molecular mechanisms for the complex series of double fertilization processes and elucidated differences and similarities between animals and plants.

Plasmogamic Paternal Contributions to Early Zygotic Development in Flowering Plants.

Flowering plant zygotes possess complete developmental potency, and the mixture of male and female genetic and cytosolic materials in the zygote is a trigger to initiate embryo development. Plasmogamy, the fusion of the gamete cytoplasms, facilitates the cellular dynamics of the zygote. In the last decade, mutant analyses, live cell imaging-based observations, and direct observations of fertilized egg cells by fusion of isolated gametes have accelerated our understanding of the post-plasmogamic events in flowering plants including cell wall formation, gamete nuclear migration and fusion, and zygotic cell elongation and asymmetric division.

Targeted reprogramming of H3K27me3 resets epigenetic memory in plant paternal chromatin.

Epigenetic marks are reprogrammed in the gametes to reset genomic potential in the next generation. In mammals, paternal chromatin is extensively reprogrammed through the global erasure of DNA methylation and the exchange of histones with protamines. Precisely how the paternal epigenome is reprogrammed in flowering plants has remained unclear since DNA is not demethylated and histones are retained in sperm.

The phenotypic morphology of human lumbar plexus roots associated with changes in the thoracolumbar vertebral count and trade-off.

This study investigated the developmental basis for the human phenotypic morphology of the interaction between the vertebrae and the nerve plexus by evaluating changes in the human lumbar plexus according to various thoracolumbar formulas. The dissection found that the changes in lumbar nerve roots reported by experimental embryology studies to be concomitant with thoracolumbar trade-off, i.e.

Derived muscle arrangements and their shared innervation patterns of external and internal cheek pouches in rodents.

Cheek pouches have evolved from the oral cavity in rodents and act as temporary food storage repositories. There are two types of opening, internal and external. Details about the complex cutaneous muscles controlling the pouches have still not been fully elucidated.