scholarly journals Comparative Structural and Functional Analyses of the Fusiform, Oval, and Triradiate Morphotypes of Phaeodactylum tricornutum Pt3 Strain

2021 ◽  
Vol 12 ◽  
Author(s):  
Ludovic Galas ◽  
Carole Burel ◽  
Damien Schapman ◽  
Marc Ropitaux ◽  
Sophie Bernard ◽  
...  
Keyword(s):  
Differential Expression ◽  
Phaeodactylum Tricornutum ◽  
Spectral Characteristics ◽  
Oval Cells ◽  
Cellular Organization ◽  
Negative Regulators ◽  
Complex Dynamic ◽  
Actin Cortex ◽  
Transmission Electron ◽  
Functional Analyses

The diatom Phaeodactylum tricornutum is a marine unicellular microalga that exists under three main morphotypes: oval, fusiform, and triradiate. Previous works have demonstrated that the oval morphotype of P. tricornutum Pt3 strain presents specific metabolic features. Here, we compared the cellular organization of the main morphotypes of the diatom P. tricornutum Pt3 strain through transmission electron and advanced light microscopies. The three morphotypes share similarities including spectral characteristics of the plastid, the location of the nucleus, the organization of mitochondria around the plastid as well as the existence of both a F-actin cortex, and an intracellular network of F-actin. In contrast, compared to fusiform and triradiate cells, oval cells spontaneously release proteins more rapidly. In addition, comparison of whole transcriptomes of oval versus fusiform or triradiate cells revealed numerous differential expression of positive and negative regulators belonging to the complex dynamic secretory machinery. This study highlights the specificities occurring within the oval morphotype underlying that the oval cells secrete proteins more rapidly.

scholarly journals Исследование электрофизических свойств квантовых точек антимонида индия: значение формы

2021 ◽  
Vol 55 (3) ◽  
pp. 237
Author(s):  
В.Ф. Кабанов ◽  
А.И. Михайлов ◽  
М.В. Гавриков
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Indium Antimonide ◽  
Spectral Characteristics ◽  
Characteristic Size ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Characteristics Analysis

In this work, we studied the influence of the shape of the indium antimonide quantum dots of on some important electrophysical parameters by spectral characteristics analysis, transmission electron microscopy, scanning tunneling microscopy, a laser particle size analyzer, and scanning electron microscopy. It is shown that the real form of quantum dots (spherical and cubic models) at the same characteristic size will noticeably affect the energy spectrum of the investigated objects and, accordingly, their electrophysical and optical properties.

Cellular organization and fine structure of type II microtrich sensilla in gammaridean amphipods (Crustacea)

1999 ◽  
Vol 77 (1) ◽  
pp. 88-107 ◽  
Author(s):  
V J Steele ◽  
D H Steele
Keyword(s):  
Sensory Neurons ◽  
Sensory Cell ◽  
Cell Process ◽  
Outer Cell ◽  
Type Ii ◽  
Cellular Organization ◽  
Insect Sensilla ◽  
Transmission Electron ◽  
Cell Processes ◽  
Tormogen Cell

The cellular organization of type II microtrich sensilla was studied in male Anonyx lilljeborgi Boeck, 1871 (Lysianassoidea) by light and transmission electron microscopy. The sensillum consists of two bipolar sensory neurons and three concentric sheath cells. The sensory cell bodies are subepidermal. In each sensillum both dendrites are enclosed by the thecogen cell process. The inner dendritic segments are filled with mitochondria and lucent vesicles and expand in the epidermis into a spindle-shaped swelling. One of the neurons gives rise to two cilia and the second to a single cilium. These three outer dendritic segments lie in the receptorlymph cavity. The dendritic sheath, secreted by the thecogen cell process, completely ensheaths the outer dendritic segments. The trichogen (middle) cell and the tormogen (outer) cell incompletely enclose the thecogen cell, but their processes form autojunctions around the dendritic sheath in the apical epidermis. In premolt, the trichogen cell processes project into the exuvial space. The cytoplasm of the tormogen cell and the bordering epidermal cells contains coarse osmiophilic inclusions. All the cells of the sensillum are joined by desmosomes. The sensilla structurally resemble chemosensory (gustatory) insect sensilla.

Protoplast Formation from Submerged Mycelium and from Spore Germinants of Streptomyces coelicolor

1985 ◽  
Vol 38 (1) ◽  
pp. 175 ◽  
Author(s):  
I Stevenson
Keyword(s):  
Cell Wall ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Streptomyces Coelicolor ◽  
Cross Wall ◽  
Cellular Organization ◽  
Protoplast Formation ◽  
Cellular Compartment ◽  
Transmission Electron ◽  
Single Region

Stages in the formation of protoplasts from S. coelicolor strain A3(2) have been studied by transmission electron microscopy. Protoplasts liberated from submerged mycelial growth were variable in size and were released when digestion of the cell wall by lysozyme had completely or almost completely taken place. Protoplasts did not fully adopt the typical rounded shape until after release. A single region of cytoplasm gave rise to more than one protoplast unit. Protoplasts released from spore germinants escaped from the tip of the germ tube, which was the region of the cell wall most susceptible to digestion. Protoplasts derived from spore germinants were more consistent in size and rounded up more rapidly. If a cross-wall had formed in a germinant then it gave rise to separate protoplasts from each cellular. compartment. Protoplasts of either type contained a single DNA region. These studies give an indication of the cellular organization of a streptomycete colony, which can be visualized as a multinucleated assemblage of cellular units in a common cytoplasm. The assembly of units separates into a number of protoplasts on digestion of the cell wall.

scholarly journals Alterations in Anatomy and Ultrastructure of Pecan Leaves Treated with Propiconazole during Shoot Expansion

2002 ◽  
Vol 127 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Hazel Y. Wetzstein ◽  
Elizabeth A. Richardson ◽  
Yi He
Keyword(s):  
Structural Changes ◽  
Leaf Expansion ◽  
Cellular Organization ◽  
Intercellular Spaces ◽  
Palisade Parenchyma ◽  
Carya Illinoensis ◽  
Mesophyll Cells ◽  
Transmission Electron ◽  
Spongy Layer ◽  
Anatomy And Ultrastructure

Propiconazole, a triazole fungicide, has been reported to inhibit leaf expansion in pecan [Carya illinoensis (Wangenh.) K. Koch] trees when applied under field conditions. This study was conducted to determine the effect of propiconazole on pecan leaf morphology and structure using light and transmission electron microscopy. Mature pecan trees were sprayed once or three times per week from budbreak to pollen maturity. Fungicide sprays resulted in significantly reduced leaf area. Compared to controls, leaves from propiconazole-treated shoots had alterations in cell arrangement characterized by more tightly packed palisade parenchyma cells with fewer intercellular spaces; neither leaf thickness nor palisade or spongy layer thickness were affected. Propiconazole caused modifications in the chloroplasts, with a tendency for internal membranes to be less defined, and for thylakiods to exhibit less stacking. The extent of structural changes was related to fungicide dosage. Results show that propiconazole applications during leaf development can inhibit leaf expansion and modify cellular organization of the mesophyll cells. Chemical name used: 1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl] methyl]-1H-1,2,4-triazole (propiconazole).

scholarly journals Functional ultrastructure of eggs and cellular organization of hexacanths of the cyclophyllidean cestode Thysanotaenia congolensis: a phylogenetic implication of obtained results

Parasitology ◽  
2015 ◽  
Vol 143 (3) ◽  
pp. 320-333 ◽  
Author(s):  
ZDZISŁAW ŚWIDERSKI ◽  
JORDI MIQUEL ◽  
DAVID BRUCE CONN
Keyword(s):  
Cell Types ◽  
Cape Verde ◽  
Cellular Organization ◽  
Protective Function ◽  
Penetration Gland ◽  
Phylogenetic Implication ◽  
Transmission Electron ◽  
Functional Ultrastructure ◽  
Medullary Parenchyma ◽  
Thysanotaenia Congolensis

SUMMARYThe functional ultrastructure of eggs and cellular organization of hexacanths from gravid proglottids of Thysanotaenia congolensis, from black rats from Cape Verde, were examined by transmission electron microscopy. Mature eggs with fully formed hexacanths are grouped within parenchymatous capsules of gravid proglottids. Oncospheral envelopes surrounding mature hexacanths are reduced to a very thin membranous embryophore as their protective function is taken over by the parenchymatous capsules originating from the medullary parenchyma of immature proglottids and composed of three layers. Six major cell types are present: a bi-nucleate medullary centre; a six-nucleate U-shaped penetration gland; a second type of penetration gland; two neurosecretory-type nerve cells; about 30 somatic cells; and about 12 germinative cells. Present results on the functional ultrastructure of eggs and cellular organization of hexacanths support the phylogenetic distinction between T. congolensis and cestodes of the subfamily Anoplocephalinae.

scholarly journals Ultrastructural Characteristics of Rat Hepatic Oval Cells and Their Intercellular Contacts in the Model of Biliary Fibrosis: New Insights into Experimental Liver Fibrogenesis

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Joanna Maria Lotowska ◽  
Maria Elzbieta Sobaniec-Lotowska ◽  
Dariusz Marek Lebensztejn ◽  
Urszula Daniluk ◽  
Piotr Sobaniec ◽  
...  
Keyword(s):  
Bile Duct ◽  
Cell Contact ◽  
Oval Cells ◽  
Cellular Interactions ◽  
Nonparenchymal Cells ◽  
Transmission Electron ◽  
Duct Ligation ◽  
Liver Fibrogenesis ◽  
Direct Cell ◽  
Hepatic Nonparenchymal Cells

Purpose. Recently, it has been emphasized that hepatic progenitor/oval cells (HPCs) are significantly involved in liver fibrogenesis. We evaluated the multipotential population of HPCs by transmission electron microscope (TEM), including relations with adherent hepatic nonparenchymal cells (NPCs) in rats with biliary fibrosis induced by bile duct ligation (BDL). Methods. The study used 6-week-old Wistar Crl: WI(Han) rats after BDL for 1, 6, and 8 weeks. Results. Current ultrastructural analysis showed considerable proliferation of HPCs in experimental intensive biliary fibrosis. HPCs formed proliferating bile ductules and were scattered in periportal connective tissue. We distinguished 4 main types of HPCs: 0, I, II (bile duct-like cells; most common), and III (hepatocyte-like cells). We observed, very seldom presented in literature, cellular interactions between HPCs and adjacent NPCs, especially commonly found transitional hepatic stellate cells (T-HSCs) and Kupffer cells/macrophages. We showed the phenomenon of penetration of the basement membrane of proliferating bile ductules by cytoplasmic processes sent by T-HSCs and the formation of direct cell-cell contact with ductular epithelial cells related to HPCs. Conclusions. HPC proliferation induced by BDL evidently promotes portal fibrogenesis. Better understanding of the complex cellular interactions between HPCs and adjacent NPCs, especially T-HSCs, may help develop antifibrotic therapies in the future.

scholarly journals Genome Organizations and Functional Analyses of a Novel Gammapartitivirus from Rhizoctonia solani AG-1 IA Strain D122

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2254
Author(s):  
Meiling Zhang ◽  
Zhenrui He ◽  
Xiaotong Huang ◽  
Canwei Shu ◽  
Erxun Zhou
Keyword(s):  
Rhizoctonia Solani ◽  
Phylogenetic Analyses ◽  
Protoplast Regeneration ◽  
Sequence Alignments ◽  
Reading Frame ◽  
Transmission Electron ◽  
Viral Particles ◽  
The Family ◽  
20 Nm ◽  
Functional Analyses

Here, we describe a novel double-stranded (ds) RNA mycovirus designated Rhizoctonia solani dsRNA virus 5 (RsRV5) from strain D122 of Rhizoctonia solani AG-1 IA, the causal agent of rice sheath blight. The RsRV5 genome consists of two segments of dsRNA (dsRNA-1, 1894 bp and dsRNA-2, 1755 bp), each possessing a single open reading frame (ORF). Sequence alignments and phylogenetic analyses showed that RsRV5 is a new member of the genus Gammapartitivirus in the family Partitiviridae. Transmission electron microscope (TEM) images revealed that RsRV5 has isometric viral particles with a diameter of approximately 20 nm. The mycovirus RsRV5 was successfully removed from strain D122 by using the protoplast regeneration technique, thus resulting in derivative isogenic RsRV5-cured strain D122-P being obtained. RsRV5-cured strain D122-P possessed the traits of accelerated mycelial growth rate, increased sclerotia production and enhanced pathogenicity to rice leaves compared with wild type RsRV5-infection strain D122. Transcriptome analysis showed that three genes were differentially expressed between two isogenic strains, D122 and D122-P. These findings provided new insights into the molecular mechanism of the interaction between RsRV5 and its host, D122 of R. solani AG-1 IA.

scholarly journals Negative Roles of Strigolactone-Related SMXL6, 7 and 8 Proteins in Drought Resistance in Arabidopsis

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 607 ◽  
Author(s):  
Weiqiang Li ◽  
Kien Huu Nguyen ◽  
Cuong Duy Tran ◽  
Yasuko Watanabe ◽  
Chunjie Tian ◽  
...  
Keyword(s):  
Drought Resistance ◽  
Leaf Surface ◽  
Anthocyanin Biosynthesis ◽  
Membrane Damage ◽  
Wild Type ◽  
Negative Regulators ◽  
Cell Membrane Damage ◽  
Increased Sensitivity ◽  
Functional Analyses ◽  
Physiological And Biochemical

Previous investigations have shown that the SUPPRESSORS OF MAX2 1-LIKE6, 7 and 8 (SMXL6, 7 and 8) proteins redundantly repress strigolactone (SL) signaling in plant growth and development. Recently, a growing body of evidence indicated that SLs positively regulate plant drought resistance through functional analyses of genes involved in SL biosynthesis and positive regulation of SL signaling. However, the functions of the SL-signaling negative regulators SMXL6, 7 and 8 in drought resistance and the associated mechanisms remain elusive. To reveal the functions of these SMXL proteins, we analyzed the drought-resistant phenotype of the triple smxl6,7,8 mutant plants and studied several drought resistance-related traits. Our results showed that the smxl6,7,8 mutant plants were more resistant to drought than wild-type plants. Physiological investigations indicated that the smxl6,7,8 mutant plants exhibited higher leaf surface temperature, reduced cuticle permeability, as well as decreases in drought-induced water loss and cell membrane damage in comparison with wild-type plants. Additionally, smxl6,7,8 mutant plants displayed an increase in anthocyanin biosynthesis during drought, enhanced detoxification capacity and increased sensitivity to abscisic acid in cotyledon opening and growth inhibition assays. A good correlation between the expression levels of some relevant genes and the examined physiological and biochemical traits was observed. Our findings together indicate that the SMXL6, 7 and 8 act as negative regulators of drought resistance, and that disruption of these SMXL genes in crops may provide a novel way to improve their drought resistance.

Cisplatin-resistant MDA-MB-231 Cell-derived Exosomes Increase the Resistance of Recipient Cells in an Exosomal miR-423-5p-dependent Manner

2019 ◽  
Vol 20 (10) ◽  
pp. 804-814 ◽  
Author(s):  
Bing Wang ◽  
Yuzhu Zhang ◽  
Meina Ye ◽  
Jingjing Wu ◽  
Lina Ma ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Differential Expression ◽  
Cell Lines ◽  
Breast Cancer Cells ◽  
Expression Profiles ◽  
Migration And Invasion ◽  
Dependent Manner ◽  
Cell Viability Assay ◽  
Transmission Electron

Background: Chemoresistance blunts the therapeutic effect of cisplatin (DDP) on Triple-Negative Breast Cancer (TNBC). Researchers have not determined to date whether exosomes confer DDP resistance to other breast cancer cells or whether exosomal transfer of miRNAs derived from DDP-resistant TNBC cells confer DDP resistance. Objective: The aim of this study was to investigate the role of exosomes in chemoresistance in breast cancer. Methods: MDA-MB-231 cells resistant to DDP (231/DDP) were established. Exosomes were isolated from 231/DDP cells (DDP/EXO) and characterized by measuring the levels of protein markers, nanoparticle tracking analysis and transmission electron microscopy. MDA-MB-231, MCF-7 and SKBR-3 cell lines were treated with the isolated DDP/EXOs and cell proliferation and cytotoxicity to DDP were evaluated using MTT assays and apoptosis analyses. Western blotting was used to examine P-glycoprotein (P-gp) expression. Additionally, a microarray was used to analyse microRNA (miRNA) expression profiles in MDA-MB-231 and 231/DDP exosomes. The effects on miRNAs were determined using RT-PCR. Exosomal miR-423-5p was extracted, and differential expression was verified. The MTT cell viability assay, flow cytometry, and Transwell and immunofluorescence assays were performed to determine if differential expression of miR-423-5p sensitized cells to DDP in vitro. Results: Under a transmission electron microscope, the isolated exosomes exhibited a round or oval shape with a diameter ranging between 40 and 100 nm. DDP/EXOs labelled with PKH67 were taken up by MDA-MB-231 cells. After an incubation with DDP/EXOs, the cell lines exhibited a higher IC50 value for cisplatin, P-gp expression, migration and invasion capabilities and a lower apoptosis rate. Furthermore, 60 miRNAs from exosomes derived from 231/DDP cells were significantly up-regulated compared to exosomes from MDA-MB-231 cells. Notably, compared to the corresponding sensitive exosomes, miR-370-3p, miR-423-5p and miR-373 were the most differentially expressed miRNAs in DDP-resistant exosomes. We chose miR-423-5p, and up-regulation and down-regulation of exosomal miR-423-5p expression significantly affected DDP resistance. Conclusions: Exosomes from DDP-resistant TNBC cells (231/DDP) altered the sensitivity of other breast cancer cells to DDP in an exosomal miR-423-5p dependent manner. Our research helps to elucidate the mechanism of DDP resistance in breast cancer.

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