Centromere structure and chromosome number in mitosis of the colourless phytoflagellate Polytoma papillatum (Chlorophyceae, Volvocales, Chlamydomonadaceae)

Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1249-1254 ◽  
Author(s):  
Klaus Werner Wolf
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chromosome Number ◽  
Higher Plants ◽  
Attachment Site ◽  
Dense Layer ◽  
Mitotic Metaphase ◽  
Serial Sections ◽  
Transmission Electron ◽  
Alternative Approach

Centromere structure is described in mitosis of the unicellular biflagellate alga Polytoma papillatum using transmission electron microscopy. The kinetochores are five-layered elements at the poleward surface of the chromosomes. The five layers consist of three dense plates interspersed by two transparent zones. The polemost dense layer serves as the attachment site for kinetochore microtubules and the innermost dense layer is intimately associated with the chromatin. The five-layered organization of the kinetochore in the alga is unusual. In animals, three-layered kinetochores are the rule. This type has also been found in some algae, while higher plants do not possess striated kinetochores. An attempt was made to determine the chromosome number of P. papillatum. Individual chromosomes could not be recognized with confidence, since there were numerous lateral contacts between the chromosomes throughout mitosis. An alternative approach, however, was successful. Counting the kinetochores in serial sections through mitotic metaphase and anaphase plates revealed a number of 15 chromosomes.Key words: anaphase, kinetochore, metaphase, microtubule.

Variation in pollen wall ultrastructure in New World Senecioneae (Asteraceae), with special reference to Packera

1997 ◽  
Vol 75 (5) ◽  
pp. 730-735 ◽  
Author(s):  
J. F. Bain ◽  
B. S. Tyson ◽  
D. F. Bray
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chromosome Number ◽  
Special Reference ◽  
New World ◽  
Pollen Wall ◽  
Wall Structure ◽  
Transmission Electron ◽  
Wall Ultrastructure ◽  
Base Chromosome Number

The structure of the pollen wall as revealed by transmission electron microscopy is presented for 34 species representing two subtribes and 12 genera of New World Senecioneae. The genus Packera (=aureoid Senecio), with the exception of Packera zimapanica, is characterized by the helianthoid wall structure. In light of these results, the disposition of the latter species requires review. The genera Robinsonecio and Telanthophora of the subtribe Tussilagininae also possess helianthoid pollen. All other taxa surveyed have senecioid pollen. So far as known no taxa exist within the tribe Senecioneae with a base chromosome number of n = 20 and helianthoid pollen. This suggests that the evolution of Packera may have involved hybridization between members of the two subtribes Senecionineae and Tussilagininae. Key words: Asteraceae, Packera, Senecioneae, pollen, TEM, systematics.

scholarly journals Same Serial Section Correlative Light and Energy-filtered Transmission Electron Microscopy

2003 ◽  
Vol 51 (5) ◽  
pp. 605-612 ◽  
Author(s):  
Ying Ren ◽  
Michael J. Kruhlak ◽  
David P. Bazett-Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscope ◽  
High Rate ◽  
Specific Cell ◽  
3D Analysis ◽  
Serial Sections ◽  
Correlative Imaging ◽  
Transmission Electron ◽  
Rate Of Success

Correlative imaging of a specific cell with both the light microscope and the electron microscope has proved to be a difficult task, requiring enormous amounts of patience and technical skill. We describe a technique with a high rate of success, which can be used to identify a particular cell in the light microscope and then to embed and thin-section it for electron microscopy. The technique also includes a method to obtain many uninterrupted, thin serial sections for imaging by conventional or energy-filtered transmission electron microscopy, to obtain images for 3D analysis of detail at the suborganelle level.

Fine structure of Classopollis exines

1986 ◽  
Vol 64 (12) ◽  
pp. 3059-3074 ◽  
Author(s):  
John R. Rowley ◽  
Satish K. Srivastava
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Upper Jurassic ◽  
Thin Sheets ◽  
Serial Sections ◽  
Thin Sections ◽  
Band Area ◽  
Transmission Electron ◽  
Oxidative Etching

Serial sections for light microscopy or transmission electron microscopy of two Classopollis pollen tetrads show that the exine structure, except for the nexine, has radially arranged rodlike units interwoven with transverse subunits. The nexine consists of strands or thin sheets except in the equatorial infratectal striate band area, where it is up to ca. 1 μm thick. Nexine is absent in the areas of the distal cryptopore and the subequatorial circumpolar infratectal canal. It is very thin or absent in the tetrad scar. Native contrast and reactivity to stain disappeared on immersion of thin sections in 1 M NaOH or HCl or in water. Reactivity to stains was regained after oxidizing the sections in KMnO4. Reactivity to stains appears to be dependent upon non-sporopollenin molecules embedded within exines. The above immersions remove stain reactive sites. Oxidative etching of sporopollenin exposes new sites. The specimens of Classopollis classoides Pflug studied and illustrated were picked from an Upper Jurassic sample (CRC 31519-2) collected at Osmington Mills locality, Dorset, England.

scholarly journals Variable opacity of glycogen in routine electron micrographs.

1977 ◽  
Vol 25 (9) ◽  
pp. 1069-1073 ◽  
Author(s):  
L E Thornell ◽  
M Sjöström ◽  
U Karlsson ◽  
E Cedergren
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Micrographs ◽  
Periodic Acid ◽  
Frog Muscle ◽  
Nerve Terminals ◽  
Lead Citrate ◽  
Serial Sections ◽  
Transmission Electron ◽  
Reticular Zone

Glycogen in nerve terminals from the reticular zone of frog muscle was identified by transmission electron microscopy of both periodic acid-thiosemicarbazide-silverproteinate treated and UAc-PbCi-stained serial sections. A variable appearance of glycogen in the uranylacetate-lead citrate-stained nerve terminals was seen and is related to the preparative procedure. The study indicates the necessity of cytochemical identification for the assessment of glycogen organization in cells.

scholarly journals A pre-embedding immunolabeling technique for basal lamina and extracellular matrix molecules.

1988 ◽  
Vol 36 (4) ◽  
pp. 453-458 ◽  
Author(s):  
M M Martins-Green ◽  
K T Tokuyasu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Extracellular Matrix ◽  
Optical Microscopy ◽  
Basal Lamina ◽  
Serial Sections ◽  
Stages Of Development ◽  
Additional Advantage ◽  
Transmission Electron ◽  
Extracellular Matrix Molecules

We have developed a pre-embedding immunolabeling technique to identify basal lamina and extracellular matrix molecules in embryos at various stages of development. The technique works for both fluorescence optical microscopy (1-2.5-micron sections) and for transmission electron microscopy, and enables straigthforward correlation between the two. An additional advantage is the easy preparation of well-oriented serial sections, facilitating detailed studies of development.

scholarly journals Nucleoid Structure of Escherichia coli as Revealed by Scanning Transmission Electron Microscopy (STEM) and by 3D-Reconstruction of Z-Contrast Images of Serial Sections

2013 ◽  
Vol 19 (S2) ◽  
pp. 144-145
Author(s):  
B. Reiner ◽  
Y. Guo ◽  
E.W. Roth ◽  
N.H. Yazdi ◽  
R.C. Johnson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
3D Reconstruction ◽  
Scanning Transmission Electron Microscopy ◽  
Serial Sections ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Nucleoid Structure ◽  
Z Contrast

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

scholarly journals Method for Combined Observation of Serial Sections of Stented Arteries Embedded in Resin by Light Microscopy and Transmission Electron Microscopy

2018 ◽  
Vol 47 (3) ◽  
pp. 401-407 ◽  
Author(s):  
Atsushi Isobe ◽  
Kouichi Iwatani ◽  
Junko Souba ◽  
Hisako Terao ◽  
Hitomi Hagiwara ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Periodic Acid ◽  
Cell Junctions ◽  
Mixed Solution ◽  
Serial Sections ◽  
Thin Sections ◽  
Transmission Electron ◽  
Ultrathin Sections

We have developed a new method for obtaining information on whole tissues by light microscopy (LM) and ultrastructural features by transmission electron microscopy (TEM). This method uses serial sections of a stented artery embedded in resin. Stents were implanted in porcine coronary arteries in this study. The heart was perfusion fixed in a 2% paraformaldehyde and 1.25% glutaraldehyde mixed solution. The stented artery was then removed, fixed in 1% osmium, embedded in Quetol 651 resin, and sectioned serially. For LM, the black color of osmium was removed from the section by immersion in periodic acid and hydrogen peroxide after deplasticization. These sections were stained with hematoxylin and eosin and Elastica–Masson trichrome stain. For TEM, thin sections were re-embedded in Quetol 812 resin by the resupinate method and cut into ultrathin sections. A clear, fine structure was obtained, and organelles, microvilli, and cell junctions in the endothelium were easily observed. The combined observation of adjacent specimens by LM and TEM enabled us to relate histopathological changes in the millimeter scale to those in the nanometer scale.

scholarly journals Using a Formvar-Coated Bridge to Apply Formvar Support Film to TEM Grids

1999 ◽  
Vol 7 (5) ◽  
pp. 18-19
Author(s):  
John P. Shields
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Conventional Method ◽  
Serial Sections ◽  
University Of Georgia ◽  
Alternative Method ◽  
Transmission Electron ◽  
Ultrathin Sections ◽  
The University

One conventional method for picking up ultrathin sections for transmission electron microscopy (TEM) is to prepare the mesh or slot grids with a formvar support film and then pick up your sections as they are floating in the knife boat. An alternative method is to first pick up sections on a naked grid and then lay them down on formvar film suspended over holes drilled in an aluminum bridge. I use this method when picking up serial sections on slot grids. A description of the method follows. The bridges I have were manufactured at the University of Georgia instrumentation Shop. They can also be purchased pre-made (for example, from SPI, Inc. They list them as Domino Racks), or one can make them from aluminum with a vise and drill. The sample bridge in the figure is similar to what I use. It is 5 cm long, 2.5 cm wide.

Ultrastructure of sperm development in the genus Ditylenchus (Nematoda: Anguinidae)

Nematology ◽  
2015 ◽  
Vol 17 (3) ◽  
pp. 313-324 ◽  
Author(s):  
Dieter Slos ◽  
Pooria Ensafi ◽  
Myriam Claeys ◽  
Vladimir V. Yushin ◽  
Wilfrida Decraemer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Outer Membrane ◽  
Higher Plants ◽  
Transmission Electron ◽  
Sperm Development ◽  
Ditylenchus Dipsaci ◽  
Mature Spermatozoa ◽  
Formation Of Complexes

Spermatogenesis in Ditylenchus arachis and D. dipsaci was studied using transmission electron microscopy. Spermatogenesis includes the formation of complexes of fibrous bodies (FB) and membranous organelles (MO) in the spermatocytes, which dissociate in separated MO and FB in the spermatids. Immature spermatozoa are unpolarised cells with separate FB and MO. Mature spermatozoa are arranged in chains. Ditylenchus dipsaci is unique in having MO that have already fused with the outer membrane in immature spermatozoa and have mature spermatozoa in the male testis, proving that not only insemination plays a role in spermiogenesis. Contrary to what has been described before, spermatogenesis in Ditylenchus, and other early diverging Tylenchomorpha, follow the typical ‘rhabditid’ pattern, while the absence of MO within Tylenchomorpha appears to be an apomorphic trait for the molecular defined clade of tylenchids that exclusively parasitise higher plants. This confirms the value of traits related to spermatogenesis in nematode phylogeny.

scholarly journals Immunogold-labelling localization of chlorophyllase at different developmental stages of Pachira macrocarpa leaves

2021 ◽  
Author(s):  
Tzan-Chain Lee ◽  
Kuan-Hung Lin ◽  
Chang-Chang Chen ◽  
Tin-Han Shih ◽  
Meng-Yuan Huang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Thylakoid Membrane ◽  
Developmental Stages ◽  
Higher Plants ◽  
Plant Cells ◽  
Immunogold Labelling ◽  
Transmission Electron

Abstract Background: Chlorophyllases (Chlases) are housekeeping proteins in plant cells. The dephytylating enzymes can catalyze chlorophyll (Chl) to form chlorophyllide, but the distribution of Chlases in plant cells is still an interesting debate. In this study, antibody of PmCLH2 was made and used by immunogold-labelling technique to detect the location of Chlase of Pachira macrocarpa (Pm) leaves at four developmental stages, including young, mature, yellowing, and senesced stages. Results: The transmission electron microscopy results show that Chlases were comprehensively found in portions of chloroplast, such as the inner membrane of the envelope, grana, and the thylakoid membrane of the chloroplast, cytosol, and vacuoles at young, mature, and yellowing stages of Pm leaves, but not in the cell wall, plasma membrane, mitochondria, and nucleus. Conclusions: PmChlases were mainly detected in vacuoles at the senescent stage, but a few were found in the chloroplasts. A pathway is proposed to explain the birth and death of Chl, Chlase, and chloroplasts in higher plants.

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