Odontoblast processes in dentin revealed by fluorescent                Di-I.

There has been controversy about the length and structure of the odontoblast process within dentin since the earliest histologic studies of teeth. Our objective was to use the fluorescent carbocyanine dye Di-I combined with a new gelatin embedment procedure and confocal microscopy to determine the structure and extent of odontoblast processes in developing and mature rat teeth, injured rat molars, reparative dentin, and adult monkey teeth. We found that odontoblast processes do not extend into outer dentin or to the dentin-enamel junction except during early stages of development. Those in innervated regions of crown are long and straight, whereas those in roots are extensively branched and shorter. Cavity injury to crown dentin caused odontoblast fragments to be aspirated into outer dentin. In reparative dentin the odontoblast processes were branched and similar to those in roots. We used photoconversion and electron microscopy to show that Di-I fills the entire odontoblast after gelatin embedment, including the cytoplasm. This is a different type of carbocyanine staining from any previously reported, and it also stains other cells in adjacent hard tissues such as bone and cementum. The Di-I-gelatin method is a new way to use carbocyanine dyes. It has enabled us to solve a long-standing controversy about the histology of teeth, and it should be useful for many other studies of cell structure.

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High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084624 ◽

1991 ◽

Vol 49 ◽

pp. 64-65

Author(s):

Marek Malecki ◽

James Pawley ◽

Hans Ris

Keyword(s):

Electron Microscopy ◽

High Pressure ◽

Low Voltage ◽

Culture Media ◽

Cell Structure ◽

Freeze Substitution ◽

Ice Crystal ◽

High Pressure Freezing ◽

Cell Culture Media ◽

Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

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Transcriptome analysis of Cinnamomum migao seed germination in medicinal plants of Southwest China

BMC Plant Biology ◽

10.1186/s12870-021-03020-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Xiaolong Huang ◽

Tian Tian ◽

Jingzhong Chen ◽

Deng Wang ◽

Bingli Tong ◽

...

Keyword(s):

Electron Microscopy ◽

Seed Germination ◽

Transcriptome Analysis ◽

Energy Supply ◽

Tricarboxylic Acid Cycle ◽

Cell Structure ◽

Seed Vigor ◽

Differentially Expressed ◽

Oil Bodies ◽

Physiological Indexes

Abstract Background Cinnamomum migao is an endangered evergreen woody plant species endemic to China. Its fruit is used as a traditional medicine by the Miao nationality of China and has a high commercial value. However, its seed germination rate is extremely low under natural and artificial conditions. As the foundation of plant propagation, seed germination involves a series of physiological, cellular, and molecular changes; however, the molecular events and systematic changes occurring during C. migao seed germination remain unclear. Results In this study, combined with the changes in physiological indexes and transcription levels, we revealed the regulation characteristics of cell structures, storage substances, and antioxidant capacity during seed germination. Electron microscopy analysis revealed that abundant smooth and full oil bodies were present in the cotyledons of the seeds. With seed germination, oil bodies and other substances gradually degraded to supply energy; this was consistent with the content of storage substances. In parallel to electron microscopy and physiological analyses, transcriptome analysis showed that 80–90 % of differentially expressed genes (DEGs) appeared after seed imbibition, reflecting important development and physiological changes. The unigenes involved in material metabolism (glycerolipid metabolism, fatty acid degradation, and starch and sucrose metabolism) and energy supply pathways (pentose phosphate pathway, glycolysis pathway, pyruvate metabolism, tricarboxylic acid cycle, and oxidative phosphorylation) were differentially expressed in the four germination stages. Among these DEGs, a small number of genes in the energy supply pathway at the initial stage of germination maintained high level of expression to maintain seed vigor and germination ability. Genes involved in lipid metabolism were firstly activated at a large scale in the LK (seed coat fissure) stage, and then genes involved in carbohydrates (CHO) metabolism were activated, which had their own species specificity. Conclusions Our study revealed the transcriptional levels of genes and the sequence of their corresponding metabolic pathways during seed germination. The changes in cell structure and physiological indexes also confirmed these events. Our findings provide a foundation for determining the molecular mechanisms underlying seed germination.

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SYNTHESIS, MIGRATION, AND RELEASE OF PRECURSOR COLLAGEN BY ODONTOBLASTS AS VISUALIZED BY RADIOAUTOGRAPHY AFTER [3H]PROLINE ADMINISTRATION

The Journal of Cell Biology ◽

10.1083/jcb.60.1.92 ◽

1974 ◽

Vol 60 (1) ◽

pp. 92-127 ◽

Cited By ~ 268

Author(s):

Melvyn Weinstock ◽

C. P. Leblond

Keyword(s):

Electron Microscopy ◽

Endoplasmic Reticulum ◽

Golgi Apparatus ◽

Phosphotungstic Acid ◽

Secretory Granules ◽

Low Ph ◽

Collagen Fibrils ◽

Dentin Collagen ◽

Odontoblast Process ◽

High Radioactivity

The elaboration of dentin collagen precursors by the odontoblasts in the incisor teeth of 30–40-g rats was investigated by electron microscopy, histochemistry, and radioautography after intravenous injection of tritium-labeled proline. At 2 min after injection, when the labeling of blood proline was high, radioactivity was restricted to the rough endoplasmic reticulum, indicating that it is the site of synthesis of the polypeptide precursors of collagen, the pro-alpha chains. At 10 min, when the labeling of blood proline had already declined, radioactivity was observed in spherical portions of Golgi saccules containing entangled threads, and, at 20 min, radioactivity appeared in cylindrical portions containing aggregates of parallel threads. The parallel threads measured 280–350 nm in length and stained with the low pH-phosphotungstic acid technique for carbohydrate and with the silver methenamine technique for aldehydes (as did extracellular collagen fibrils). The passage of label from spherical to cylindrical Golgi portions is associated with the reorganization of entangled into parallel threads, which is interpreted as the packing of procollagen molecules. Between 20 and 30 min, prosecretory and secretory granules respectively became labeled. These results indicate that the cylindrical portions of Golgi saccules transform into prosecretory and subsequently into secretory granules. Within these granules, the parallel threads, believed to be procollagen molecules, are transported to the odontoblast process. At 90 min and 4 h after injection, label was present in predentin, indicating that the labeled content of secretory granules had been released into predentin. This occurred by exocytosis as evidenced by the presence of secretory granules in fusion with the plasmalemma of the odontoblast process. It is proposed that pro-alpha chains give rise to procollagen molecules which assemble into parallel aggregates in the Golgi apparatus. Procollagen molecules are then transported within secretory granules to the odontoblast process and released by exocytosis. In predentin procollagen molecules would give rise to tropocollagen molecules, which would then polymerize into collagen fibrils.

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Morphology and behaviour of dinoflagellate chromosomes during the cell cycle and mitosis

Journal of Cell Science ◽

10.1242/jcs.113.7.1231 ◽

2000 ◽

Vol 113 (7) ◽

pp. 1231-1239 ◽

Cited By ~ 3

Author(s):

Y. Bhaud ◽

D. Guillebault ◽

J. Lennon ◽

H. Defacque ◽

M.O. Soyer-Gobillard ◽

...

Keyword(s):

Electron Microscopy ◽

Cell Cycle ◽

Confocal Microscopy ◽

Nuclear Envelope ◽

Chromosome Segregation ◽

Morphological Changes ◽

S Phase ◽

Chromosome Behaviour ◽

Double Number ◽

Do So

The morphology and behaviour of the chromosomes of dinoflagellates during the cell cycle appear to be unique among eukaryotes. We used synchronized and aphidicolin-blocked cultures of the dinoflagellate Crypthecodinium cohnii to describe the successive morphological changes that chromosomes undergo during the cell cycle. The chromosomes in early G(1) phase appeared to be loosely condensed with numerous structures protruding toward the nucleoplasm. They condensed in late G(1), before unwinding in S phase. The chromosomes in cells in G(2) phase were tightly condensed and had a double number of arches, as visualised by electron microscopy. During prophase, chromosomes elongated and split longitudinally, into characteristic V or Y shapes. We also used confocal microscopy to show a metaphase-like alignment of the chromosomes, which has never been described in dinoflagellates. The metaphase-like nucleus appeared flattened and enlarged, and continued to do so into anaphase. Chromosome segregation occurred via binding to the nuclear envelope surrounding the cytoplasmic channels and microtubule bundles. Our findings are summarized in a model of chromosome behaviour during the cell cycle.

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Odontoblast processes in human dentin revealed by fluorescence labeling and transmission electron microscopy

Histochemistry and Cell Biology ◽

10.1007/s00418-002-0442-y ◽

2002 ◽

Vol 118 (3) ◽

pp. 205-212 ◽

Cited By ~ 25

Author(s):

Kunihiko Yoshiba ◽

Nagako Yoshiba ◽

Sadakazu Ejiri ◽

Masaaki Iwaku ◽

Hidehiro Ozawa

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Fluorescence Labeling ◽

Transmission Electron ◽

Human Dentin ◽

Odontoblast Processes

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The use of confocal microscopy in the investigation of cell structure and function in the heart, vascular endothelium and smooth muscle cells

Novel Methods in Molecular and Cellular Biochemistry of Muscle ◽

10.1007/978-1-4615-6353-2_18 ◽

1997 ◽

pp. 171-194 ◽

Cited By ~ 3

Author(s):

Ghassan Bkaily ◽

Pierre Pothier ◽

Pedro D’Orléans-Juste ◽

May Simaan ◽

Danielle Jacques ◽

...

Keyword(s):

Smooth Muscle ◽

Confocal Microscopy ◽

Smooth Muscle Cells ◽

Vascular Endothelium ◽

Cell Structure ◽

Muscle Cells ◽

Structure And Function ◽

And Function

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The AMF-R tubule is a smooth ilimaquinone-sensitive subdomain of the endoplasmic reticulum

Journal of Cell Science ◽

10.1242/jcs.110.24.3043 ◽

1997 ◽

Vol 110 (24) ◽

pp. 3043-3053 ◽

Cited By ~ 3

Author(s):

H.J. Wang ◽

N. Benlimame ◽

I. Nabi

Keyword(s):

Electron Microscopy ◽

Confocal Microscopy ◽

Immunofluorescence Microscopy ◽

Mdck Cells ◽

Autocrine Motility Factor ◽

Motility Factor ◽

Membranous Tubule ◽

Intermediate Compartment ◽

Rough Er ◽

Golgi Network

Autocrine motility factor receptor (AMF-R) is a marker for a distinct smooth membranous tubule. Ilimaquinone (IQ) is a sea sponge metabolite which induces the complete vesiculation of the Golgi apparatus and we show here that the addition of IQ to MDCK cells also results in the disruption of the AMF-R tubule. By immunofluorescence microscopy, the resultant punctate AMF-R label resembles the products of IQ-mediated vesiculation of the trans-Golgi network, however, the two labels can be distinguished by confocal microscopy. AMF-R tubule fragmentation occurs after nocodazole or taxol treatment of the cells demonstrating that the action of IQ on AMF-R tubules is not related to the ability of IQ to depolymerize microtubules. IQ activity is therefore not Golgi-specific. Electron microscopy of IQ-treated cells reveals that AMF-R is distributed to fenestrated networks of narrow interconnected tubules which are distinguishable from the uniform Golgi-derived vesicles and morphologically equivalent to smooth ER. Distinct fenestrations are visible in incompletely fragmented tubules which may represent intermediates in the fragmentation process. Smooth AMF-R labeled tubules exhibit continuity with rough ER cisternae and IQ selectively targets smooth and not rough ER. AMF-R tubules can be distinguished from the intermediate compartment labeled for ERGIC-53 by confocal microscopy and thus constitute a distinct IQ-sensitive subdomain of the smooth ER.

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Kuru, the First Human Prion Disease

Viruses ◽

10.3390/v11030232 ◽

2019 ◽

Vol 11 (3) ◽

pp. 232 ◽

Cited By ~ 12

Author(s):

Paweł Liberski ◽

Agata Gajos ◽

Beata Sikorska ◽

Shirley Lindenbaum

Keyword(s):

Electron Microscopy ◽

Confocal Microscopy ◽

Prion Disease ◽

Amyloid Plaques ◽

Human Medicine ◽

Spongiform Encephalopathy ◽

Biomedical Sciences ◽

Human Prion Disease ◽

History Of ◽

Jakob Disease

Kuru, the first human prion disease was transmitted to chimpanzees by D. Carleton Gajdusek (1923–2008). In this review, we summarize the history of this seminal discovery, its anthropological background, epidemiology, clinical picture, neuropathology, and molecular genetics. We provide descriptions of electron microscopy and confocal microscopy of kuru amyloid plaques retrieved from a paraffin-embedded block of an old kuru case, named Kupenota. The discovery of kuru opened new vistas of human medicine and was pivotal in the subsequent transmission of Creutzfeldt–Jakob disease, as well as the relevance that bovine spongiform encephalopathy had for transmission to humans. The transmission of kuru was one of the greatest contributions to biomedical sciences of the 20th century.

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