Tube Extension Research Articles

Transcriptome and Metabolome Analyses Reveal a Complex Stigma Microenvironment for Pollen Tube Growth in Tobacco.

In flowering plants, the success of fertilization depends on the rapid polar extension of a pollen tube, which delivers sperm cells to the female gametophyte for fertilization. Numerous studies have shown that the microenvironment in planta is more conducive to the growth and development of pollen tubes than that in vitro. However, how stigma factors coordinate to regulate pollen tube growth is still poorly understood. Here, we demonstrate that in tobacco, mature stigma extract, but not immature stigma extract, facilitates pollen tube growth. Comparative transcriptomic and qRT-PCR analyses showed that the differentially expressed genes during stigma maturation were mainly enriched in the metabolism pathway. Through metabolome analyses, about 500 metabolites were identified to be differently accumulated; the significantly increased metabolites in the mature stigmas mainly belonged to alkaloids, flavonoids, and terpenoids, while the downregulated differential metabolites were related to lipids, amino acids, and their derivatives. Among the different kinds of plant hormones, the cis-form contents of zeatin were significantly increased, and more importantly, cis-zeatin riboside promoted pollen tube growth in vitro. Thus, our results reveal an overall landscape of gene expression and a detailed nutritional microenvironment established for pollen tube growth during the process of stigma maturation, which provides valuable clues for optimizing in vitro pollen growth and investigating the pollen-stigma interaction.

Single-cell morphometrics reveals T-box gene-dependent patterns of epithelial tension in the Second Heart field

The vertebrate heart tube extends by progressive addition of epithelial second heart field (SHF) progenitor cells from the dorsal pericardial wall. The interplay between epithelial mechanics and genetic mechanisms during SHF deployment is unknown. Here, we present a quantitative single-cell morphometric analysis of SHF cells during heart tube extension, including force inference analysis of epithelial stress. Joint spatial Principal Component Analysis reveals that cell orientation and stress direction are the main parameters defining apical cell morphology and distinguishes cells adjacent to the arterial and venous poles. Cell shape and mechanical forces display a dynamic relationship during heart tube formation. Moreover, while the T-box transcription factor Tbx1 is necessary for cell orientation towards the arterial pole, activation of Tbx5 in the posterior SHF correlates with the establishment of epithelial stress and SHF deletion of Tbx5 relaxes the progenitor epithelium. Integrating findings from cell-scale feature patterning and mechanical stress provides new insights into cardiac morphogenesis.

Study on the biocontrol effect of Streptomyces sp. NEAU-KT41 and its cell-free culture filtrate against wheat root rot

Wheat root rot, caused by Bipolaris sorokiniana, is a significant and extensive soilborne disease. Streptomyces sp. NEAU-KT41 was isolated from healthy wheat root soil and possessed strong antifungal activity against B. sorokiniana. Findings from the pot test indicated that strain NEAU-KT41 (108 CFU/mL) and its 10 % cell-free culture filtrate had significant biocontrol efficiency against wheat root rot, with 66.67 % and 64.4 %, respectively, resulting in significant increases in biomass and chlorophyll content. For 108 CFU/mL spore suspension, the plant height increased by 167.52 %; root length by 141.64 %, fresh weight by 65 %, chlorophyll a by 13.43 %, and chlorophyll b by 51.02 % under disease stress. For the 10 % cell-free culture filtrate, the plant height increased by 21.93 %, root length by 17.92 %, dry weight by 29.35 %, chlorophyll a by 17.92 %, and chlorophyll b by 82.15 % under disease stress. Moreover, strain NEAU-KT41 could produce proteases, amylases, lipases, and ACC deaminase, and had the ability to decompose organic phosphorus and fix nitrogen. The cell-free culture filtrate affected B. sorokiniana in several manners, including increasing the cell membrane permeability, diminishing the soluble protein content in the mycelia, impeding conidia germination and germ tube extension, and affecting B. sorokiniana invasion of plants. Briefly, Streptomyces sp. NEAU-KT41 is a prospective biocontrol agent that can be used to manage root rot in wheat and has potential applications.

Differential proliferation regulates multi-tissue morphogenesis during embryonic axial extension: integrating viscous modeling and experimental approaches.

A major challenge in biology is to understand how mechanical interactions and cellular behavior affect the shapes of tissues and embryo morphology. The extension of the neural tube and paraxial mesoderm, which form the spinal cord and musculoskeletal system, respectively, results in the elongated shape of the vertebrate embryonic body. Despite our understanding of how each of these tissues elongates independently of the others, the morphogenetic consequences of their simultaneous growth and mechanical interactions are still unclear. Our study investigates how differential growth, tissue biophysical properties and mechanical interactions affect embryonic morphogenesis during axial extension using a 2D multi-tissue continuum-based mathematical model. Our model captures the dynamics observed in vivo by time-lapse imaging of bird embryos, and reveals the underestimated influence of differential tissue proliferation rates. We confirmed this prediction in quail embryos by showing that decreasing the rate of cell proliferation in the paraxial mesoderm affects long-term tissue dynamics, and shaping of both the paraxial mesoderm and the neighboring neural tube. Overall, our work provides a new theoretical platform upon which to consider the long-term consequences of tissue differential growth and mechanical interactions on morphogenesis.

Erratum to “Application of the cylinder-type driver tube staging valve for test time extension of shock tube”

Erratum to “Application of the cylinder-type driver tube staging valve for test time extension of shock tube”

Folding Auxetic Polygonal Kirigami Tubes

Abstract Tubular auxetic structures have wide-ranging applications including medical stents, collapsible energy absorbers, and novel fasteners. To accelerate the development in these areas, and open up new application directions, an expanded range of design and construction methods for auxetic tubes is required. In this study, we propose a new method to construct polygonal cross-sectional auxetic tubes using the principles of origami and kirigami. These tubes exhibit useful global auxetic behavior under axial extension, despite the individual polygon faces not being auxetic themselves. In general, a flat kirigami sheet cannot be simply folded into a polygonal tube since this creates kinematic incompatibilities along the polygon edges. We resolve this issue by replacing the edge folds with an origami mechanism consisting of a pair of triangular facets. This approach eliminates the incompatibilities at the edges while maintaining a connection between faces. The proposed edge connection also introduces additional control parameters for the tube kinematics: for example, introducing a kinematic limit on tube extension and enabling non-uniform behavior along the length of the tube. The rich kinematic behavior possible with polygonal cross-sectional kirigami tubes has potential applications ranging from soft robotics to energy-dissipating devices.

Application of the cylinder-type driver tube staging valve for test time extension of shock tube

Application of the cylinder-type driver tube staging valve for test time extension of shock tube

Bayesian model updating of super high‐rise building for construction simulation

SummaryA finite element model was established using SAP2000 software for the C1 tower, a super high‐rise building in the second phase of the Nanjing Financial City project, and the construction process of the tower was simulated. The C1 tower adopts a frame core tube extension arm and ring truss structure system, with 87 floors above ground and five floors underground. The roof structure has an elevation of 416.6 m. Precise measurements of inter‐story compression deformation were conducted using advanced surveying equipment. Sensitivity analysis, based on the finite difference method, identified the shear wall elastic modulus, frame column elastic modulus, steel beam elastic modulus, and shear wall unit weight as four highly influential parameters. Employing the Bayesian principle, the Markov Chain Monte Carlo (MCMC) method was applied to determine the posterior density probability function of the parameters targeted for modification. Subsequently, the Metropolis–Hastings (MH) sampling algorithm was employed to refine the C1 Tower model. This refinement significantly reduced the root mean square error between the measured and simulated vertical displacements, achieving an error reduction of approximately 10% from 6.082 to around 2.160. The modified material parameters, for the most part, adhered to a normal distribution assumption and exhibited mean values in the posterior probability density functions for the elastic modulus of Q345 steel beams, C70 frame columns, and C60 shear walls. Compared to the initial finite element parameters, the variation range was approximately 13% to 17%. These results serve as a validation of the effectiveness of the proposed method.

Calmodulin-Domain Protein Kinase PiCDPK1 Interacts with the 14-3-3-like Protein NtGF14 to Modulate Pollen Tube Growth

Calcium-mediated signaling pathways are known to play important roles in the polar growth of pollen tubes. The calcium-dependent protein kinase, PiCDPK1, has been shown to be involved in regulating this process through interaction with a guanine dissociation inhibitor, PiRhoGDI1. To more fully understand the role of PiCDPK1 in pollen tube extension, we designed a pull-down study to identify additional substrates of this kinase. These experiments identified 123 putative interactors. Two of the identified proteins were predicted to directly interact with PiCDPK1, and this possibility was investigated in planta. The first, NtGF14, a 14-3-3-like protein, did not produce a noticeable phenotype when overexpressed in pollen alone but partially rescued the spherical tube phenotype caused by PiCDPK1 over-expression when co-over-expressed with the kinase. The second, NtREN1, a GTPase activating protein (GAP), severely inhibited pollen tube germination when over-expressed, and its co-over-expression with PiCDPK1 did not substantially affect this phenotype. These results suggest a novel in vivo interaction between NtGF14 and PiCDPK1 but do not support the direct interaction between PiCDPK1 and NtREN1. We demonstrate the utility of the methodology used to identify potential protein interactions while confirming the necessity of additional studies to confirm their validity. Finally, additional support was found for intersection between PiCDPK1 and RopGTPase pathways to control polar growth at the pollen tube tip.

Abstract 25 Cord Blood Mononuclear Cells and Cord Blood Plasma Alter Human Cardiac Endothelial Cell Angiogenic Sprouting and Growth In Vitro

Abstract Introduction The mononuclear cell fraction of human placental cord blood (CBMNC) comprises immune cells, hematopoietic, mesenchymal and other stem or progenitor cells. CBMNCs are proposed to afford therapeutic benefit based on their paracrine release of multiple cytokines, growth factors and other proteins that stimulate signalling for wound healing, including attenuation of inflammation and fibrosis. Whether CBMNCs augment angiogenic sprouting and tube formation by endothelial cells in human ventricular myocardium is not well characterised. Objectives The aim of this study was to investigate the in vitro influence of CBMNCs on endothelial cell angiogenic-like growth. Methods A tube formation assay for human donor primary ventricular myocardium microvascular endothelial cells (HMVECs), (3 female donors, age 48-50 yrs, 3 replicates per treatment group) was established using Matrigel-coated 96-well plates (62,500-78,125 cells/cm2). Cells from passage 5-8 were used for all experiments.. Angiogenic processes, as characterized by endothelial sprouting followed by tube extension into honeycomb-like mesh structures, were imaged over 24 hours. HMVECs were treated with CBMNCs at a concentration of 1:10 (MNC:HMVEC) or cord blood plasma (1μg/μL) at 0h, 3h, or 6h after the HMVECs were seeded. The cells were visualized by phase contrast microscope and images (4x magnification) were analysed using the Angiogenesis Analyzer plugin in FIJI ImageJ. Size exclusion chromatography and multiplex ELISAs were performed to determine the presence of analytes in media collected from each well. Results CBMNC-treated HMVECs exhibited greater average total elongated branching length and more tube-like structured meshes, compared to untreated controls. MMP-1, MMP-2, MMP-9, MMP-10, TIMP-1, TIMP-2, angiopoietin-2, EGF, endoglin, endothelin-1, FGF-2, follistatin, HB-EGF, IL-8, PLGF, VEGF-A, and VEGF-C were detected in extracellular media during in vitro tube formation. With CBMNC treatment, only MMP-9 was increased by 475.94%, whereas angiopoietin-2, follistatin, and PLGF levels were decreased by 27.90%, 15.90%, and 26.18% respectively. In contrast, CB plasma-treated HMVECs did not form tube sprouts, instead an intense endothelial cell proliferation was observed which was associated with increased MMP-2, MMP-9, endothelin-1 and IL-8 levels with decreased angiopoietin-2, HB-EGF, PLGF, and endoglin levels. Discussion CBMNC treatment enhanced pro-angiogenic processes in HMVECs in vitro through increased branching and network formation, whereas CB plasma evoked cell proliferation.

Extension and inflation of a thick-cylindrical tube made of isotropic compressible of Mooney–Rivlin materials: modeling and finite element simulations

Extension and inflation of a thick-cylindrical tube made of isotropic compressible of Mooney–Rivlin materials: modeling and finite element simulations

Application of sensitivity analysis in extension, inflation, and torsion of residually stressed circular cylindrical tubes

This paper deals with applying two main sensitivity analysis (SA) methods, namely, the Sobol method and the Fourier Amplitude Sensitivity Test (FAST) method on the problem of mixed extension, inflation, and torsion of a circular cylindrical tube in the presence of residual stress. The mechanical side of the problem was previously proposed by Merodio & Ogden (2016). The input parameters in the form of the initial cylinder geometry, the amount of the residual stress, the azimuthal stretch, the axial elongation, and the torsional strain are distributed according to three probability distribution methods, namely the uniform, the gamma, and the normal distribution. In the present work, through applying Sobol and FAST methods, the most influential factors among input parameters on the output variable have been determined. The assessment of our results is then determined by the computation of bias and standard deviation of Sobol and FAST indices for each input parameter in the model.

Activity of the new OSBP inhibitor Y18501 against Pseudoperonospora cubensis and its application for the control of cucumber downy mildew

Y18501 is a new oxysterol-binding protein inhibitor (OSBPI) with a similar structure to oxathiapiprolin. Y18501 showed strong inhibitory activities against Phytophthora spp. and Pseudoperonospora cubensis, with EC50 ranging from 0.0005 to 0.0046 μg/mL. It also had good control efficacy on cucumber downy mildew (CDM) in the green house and in the field, and could effectively inhibit different development stages of P. cubensis, especially for sporangiophore production, sporangial production, mycelium extension, and elongation of germ tube. In addition, Y18501 showed excellent protective and curative activities against P. cubensis. It also had acropetal systemic mobility in the cucumber leaves, and could be taken up and translocated to the upper leaves more effectively from the lower leaves than from the roots. Y18501 had poorer permeability in cucumber leaves compared to oxathiapiprolin. The simultaneous application of Y18501 and chlorothalonil could significantly promote the inhibition of P. cubensis.

Enhanced gastric decompression for palliation of malignant bowel obstruction.

Malignant bowel obstruction (MBO) is a sequela of advanced intraabdominal cancer and has a profound impact on quality of life. Common therapy is endoscopic decompressive gastrostomy tube placement. Standard gastrostomy tubes are poorly designed to completely evacuate the dependent portions of the stomach due to their location on the anterior gastric wall. In our institution we have begun placing the ASPIRE Assist gastrostomy tube (ASPIRE Bariatrics, Exton, PA) which includes a 15cm long, 30Fr fenestrated gastric tube extension for enhanced gastric decompression. This tube is FDA indicated for gastric decompression and marketed for endoscopic weight loss. The purpose of this study is to review our experience managing MBO utilizing the ASPIRE Assist tube. This is a retrospective analysis of outcomes at a single institution. All decompressive endoscopic gastrostomy tubes placed by two surgeons between November 2019 and July 2021 were reviewed. Endoscopic placement was performed utilizing standard safe tract and Ponsky pull techniques. Fourteen patients were identified (10F:4M), mean age 70 (range 35-89). Primary cancer diagnoses included gynecologic (8), colorectal (3), bladder (1), small bowel (1), peritoneal serous (1). During the 12months before decompressive gastrostomy tube placement, mean number of hospital admissions for MBO was 1.6 (range 1-3). Following tube placement, twelve patients had no further hospital admissions for MBO over their lifespan of mean 270days (range 8-679days). One patient had 1 admission for MBO in the 12months before tube placement and 3 admissions in the 4months after placement. A second patient had 2 admissions in the 12months before tube placement and 1 admission in their 54-day lifespan after placement. There were no major complications. Endoscopic placement of the ASPIRE Assist gastrostomy tube is safe for palliation of MBO and may improve gastric decompression compared with standard endoscopic gastrostomy tubes. Enhanced gastric decompression can better manage symptoms, reduce hospital encounters, and improve quality of life. Further study is needed, however, our initial data appears promising.

Placement and Extension of Glaucoma Drainage Devices Using Polypropylene Suture in Pediatric Patients.

Glaucoma drainage device tube placement and extension in pediatric patients may be complicated by abnormal anterior segment anatomy and corneal opacities. The authors describe two techniques for placement and extension of non-valved glaucoma drainage device tubes using polypropylene suture as a guidewire and stabilizer, respectively. [J Pediatr Ophthalmol Strabismus. 2022;59(5):e62-e65.].

The Outcomes of Nutritional Support Techniques in Patients with Gastrointestinal Cancers

Gastrointestinal cancers represent a major cause of morbidity and mortality worldwide. A significant issue regarding the therapeutic management of these patients consists of metabolic disturbances and malnutrition. Nutritional deficiencies have a negative impact on both the death rates of these patients and the results of surgical or oncological treatments. Thus, current guidelines recommend the inclusion of a nutritional profile in the therapeutic management of patients with gastrointestinal cancers. The development of digestive endoscopy techniques has led to the possibility of ensuring the enteral nutrition of cancer patients without oral feeding through minimally invasive techniques and the avoidance of surgeries, which involve more risks. The enteral nutrition modalities consist of endoscopy-guided nasoenteric tube (ENET), percutaneous endoscopic gastrostomy (PEG), percutaneous endoscopic gastrostomy with jejunal tube extension (PEG-J), direct percutaneous endoscopic jejunostomy (DPEJ) or endoscopic ultrasound (EUS)-guided gastroenterostomy.

SPATULA and ALCATRAZ confer female sterility and fruit cavity via mediating pistil development in cucumber.

Fruits and seeds play essential roles in plant sexual reproduction and the human diet. Successful fertilization involves delivery of sperm in the pollen tube to the egg cell within the ovary along the transmitting tract (TT). Fruit cavity is an undesirable trait directly affecting cucumber (Cucumis sativus) commercial value. However, the regulatory genes underlying fruit cavity formation and female fertility determination remain unknown in crops. Here, we characterized a basic Helix-Loop-Helix (bHLH) gene C. sativus SPATULA (CsSPT) and its redundant and divergent function with ALCATRAZ (CsALC) in cucumber. CsSPT transcripts were enriched in reproductive organs. Mutation of CsSPT resulted in 60% reduction in female fertility, with seed produced only in the upper portion of fruits. Csspt Csalc mutants displayed complete loss of female fertility and fruit cavity due to carpel separation. Further examination showed that stigmas in the double mutant turned outward with defective papillae identity, and extracellular matrix contents in the abnormal TT were dramatically reduced, which resulted in no path for pollen tube extension and no ovules fertilized. Biochemical and transcriptome analysis showed that CsSPT and CsALC act in homodimers and heterodimers to confer fruit cavity and female sterility by mediating genes involved in TT development, auxin-mediated signaling, and cell wall organization in cucumber.

MoOpy2 is essential for fungal development, pathogenicity, and autophagy in Magnaporthe oryzae.

The development and pathogenicity of the fungus Magnaporthe oryzae, the causal agent of destructive rice blast disease, require it to perceive external environmental signals. Opy2, an overproduction-induced pheromone-resistant protein 2, is a crucial protein for sensing external signals in Saccharomyces cerevisiae. However, the biological functions of the homologue of Opy2 in M. oryzae are unclear. In this study, we identified that MoOPY2 is involved in fungal development, pathogenicity, and autophagy in M. oryzae. Deletion of MoOPY2 resulted in pleiotropic defects in hyphal growth, conidiation, germ tube extension, appressorium formation, appressorium turgor generation, and invasive growth, therefore leading to attenuated pathogenicity. Furthermore, MoOpy2 participates in the Osm1 MAPK pathway and the Mps1 MAPK pathway by interacting with the adaptor protein Mst50. The interaction sites of Mst50 and MoOpy2 colocalized with the autophagic marker protein MoAtg8 in the preautophagosomal structure sites (PAS). Notably, the ΔMoopy2 mutant caused cumulative MoAtg8 lipidation and rapid GFP-MoAtg8 degradation in response to nitrogen starvation, showing that MoOpy2 is involved in the negative regulation of autophagy activity. Taken together, our study revealed that MoOpy2 of M. oryzae plays an essential role in the orchestration of fungal development, appressorium penetration, autophagy and pathogenesis.

Repair of Taussig-Bing anomaly with unusual coronary pattern using autologous pericardial tube extension

The incidence of unusual coronary patterns including single coronary artery is high in Taussig-Bing anomaly (TBA). The relocation of a single coronary artery from a nonfacing sinus can be technically challenging with implications on early and late outcomes. Many innovative techniques for coronary transfer have been described and no coronary pattern precludes arterial switch operation in the current era. We describe a technique of coronary transfer using autologous pericardial tube extension with good early outcome.

Axial elongation of caudalized human organoids mimics aspects of neural tube development.

Axial elongation of the neural tube is crucial during mammalian embryogenesis for anterior-posterior body axis establishment and subsequent spinal cord development, but these processes cannot be interrogated directly in humans as they occur post-implantation. Here, we report an organoid model of neural tube extension derived from human pluripotent stem cell (hPSC) aggregates that have been caudalized with Wnt agonism, enabling them to recapitulate aspects of the morphological and temporal gene expression patterns of neural tube development. Elongating organoids consist largely of neuroepithelial compartments and contain TBXT+SOX2+ neuro-mesodermal progenitors in addition to PAX6+NES+ neural progenitors. A critical threshold of Wnt agonism stimulated singular axial extensions while maintaining multiple cell lineages, such that organoids displayed regionalized anterior-to-posterior HOX gene expression with hindbrain (HOXB1) regions spatially distinct from brachial (HOXC6) and thoracic (HOXB9) regions. CRISPR interference-mediated silencing of TBXT, a Wnt pathway target, increased neuroepithelial compartmentalization, abrogated HOX expression and disrupted uniaxial elongation. Together, these results demonstrate the potent capacity of caudalized hPSC organoids to undergo axial elongation in a manner that can be used to dissect the cellular organization and patterning decisions that dictate early human nervous system development.