scholarly journals Cell Surfaces and Fibre Relationships in Sympathetic Ganglion Cultures: A Scanning Electron-Microscopic Study

1974 ◽  
Vol 14 (3) ◽  
pp. 657-669
Author(s):  
CARYL E. HILL ◽  
JULIE H. CHAMLEY ◽  
G. BURNSTOCK

Sympathetic ganglia from newborn rats and guinea-pigs were grown in modified Rose chambers and examined with scanning electron microscopy after 5-7 days. The cell types seen were macrophages, neurons, glial cells and connective tissue cells. They presented a wide range of surface morphologies and 3-dimensional configurations, from spheroid with an irregular surface to flattened with a smooth surface. The arrangement of the nerve fibres and cells in the outgrowth was essentially 2-layered with connective tissue cells nearest the substrate and nerve fibres, glial cells and macrophages lying over them. The relationships of sympathetic nerve fibres to the different cell types were also investigated. In all cases nerve fibres closely followed the cellular surface contours although the nature of the relationships varied. Fine finger-like cytoplasmic projections were sometimes seen from connective tissue cells and macrophages. The possible role of these structures in adhesion and motility is discussed.

Author(s):  
S. Tai

Extensive cytological and histological research, correlated with physiological experimental analysis, have been done on the anterior pituitaries of many different vertebrates which have provided the knowledge to create the concept that specific cell types synthesize, store and release their specific hormones. These hormones are stored in or associated with granules. Nevertheless, there are still many doubts - that need further studies, specially on the ultrastructure and physiology of these endocrine cells during the process of synthesis, transport and secretion, whereas some new methods may provide the information about the intracellular structure and activity in detail.In the present work, ultrastructural study of the hormone-secretory cells of chicken pituitaries have been done by using TEM as well as HR-SEM, to correlate the informations obtained from 2-dimensional TEM micrography with the 3-dimensional SEM topographic images, which have a continous surface with larger depth of field that - offers the adventage to interpretate some intracellular structures which were not possible to see using TEM.


2018 ◽  
Vol 44 (3) ◽  
pp. 385-389
Author(s):  
Ravish Choudhary ◽  
SK Malik ◽  
Rekha Chaudhury ◽  
Digvender Pal ◽  
Pravin Patel ◽  
...  

The freezing behaviour studies of dormant buds, were examined, employing scanning electron microscopy (SEM) and light microscopy. The differences and effect of freezing behaviour on dormant buds were observed. The dormant bud primordia of several woody plant species avoid freezing injury by deep supercooling. By slow cooling (5°C/day) of dormant buds to –30°C, all living cells in bud tissues exhibited distinct shrinkage without intracellular ice formation detectable by SEM. However, the recrystallization experiment of these slowly cooled tissue cells, which was done by further freezing of slowly cooled buds with liquid nitrogen (LN) and then rewarming to –10°C, confirmed that some of the cells in the apical meristem, area in which cells had thin walls and in which no extracellular ice accumulated, lost freezable water with slow cooling to –30°C, indicating adaptation of these cells by deep super cooling. Water in plant tissues will not supercool unless heterogeneous ice nucleating substances are absent and the spread of ice from adjacent tissue can be prevented. Deep supercooling could not occur in dormant bud primordia if xylem vessels formed a continuous conduit connecting the dormant bud primordia with the remainder of the plant. If xylem continuity was established, ice could propagate via the vascular system and nucleate the water within the primordia. It is concluded that no extracellular ice crystals accumulated in such tissues containing deep supercooling cells with thin cell walls.


2020 ◽  
Author(s):  
Srinivas Ramachandra ◽  
Abdulla Abdal-hay ◽  
Pingping Han ◽  
Ryan Lee ◽  
Saso Ivanovski

<p><strong>Introduction</strong>: Biofilms are 3-dimensional (3D) aggregates of microorganisms that are associated with a wide range of diseases. Although there have been several studies investigating biofilm formation on two-dimensional substrates, the use of 3D substrates may result in more representative and clinically relevant models. Accordingly, the aim of this study was to compare the growth of biofilms in the 3D substrates against biofilms grown in 2D substrates.<br /><strong>Material and Methods:</strong> Two grams of medical grade polycaprolactone (PCL) were loaded into a plastic Luer-lock 3 ml syringe and a 23G needle was used as a spinneret. The syringe was placed in a melt electro-writing (MEW) device to obtain fine fibers under controlled parameters. The 3-dimensional MEW PCL scaffolds were manufactured and characterised with an overall thickness of ~ 0.8 mm, with ~ 15 μm diameter fibers and ordered pore sizes of either 100 or 250 µm. PCL films employed as 2D substrates were manufactured by dissolving 10 gms of PCL in 100 ml chloroform and stirred for 3 h to obtain a transparent solution. Then, the solution was cast in glass petri dishes and dried to remove all organic solvents. In addition, commercial hydroxyapatite discs were also used as 2D controls. Unstimulated saliva from six healthy donors (gingival health) were used to grow biofilms. The formed biofilms were assessed at day 4, day 7 and day 10 using crystal violet assay, confocal microscopy, scanning electron microscopy and next-generation 16s sequencing.<br /><strong>Results:</strong> The results demonstrates that 3D PCL scaffolds dramatically enhanced biofilm biomass and thickness growth compared to that of the 2D controls. Confocal microscopy of biofilms at day 4 stained with SYTO 9 and propidium iodide showed thickness of biofilms in 2D substrates were 39 µm and 81µm for hydroxyapatite discs and PCL films, respectively. Biofilms in 3D substrates were 250 µm and 338 µm for MEW PCL 100µm pore size and MEW PCL 250 µm pore size, respectively. Similar results were noticed at day 7 and day 10. Scanning electron microscopy showed biofilm bridges formed over the fibers of the MEW scaffolds. Pilot trials of next generation sequencing detected similar taxa in biofilms formed in 3D scaffolds compared to that of 2D substrates.<br /><strong>Discussion:</strong> We have successfully investigated a 3D biofilm growth model using 3D medical grade PCL scaffolds. Thicker biofilms can be conveniently grown using this inexpensive static model. This will facilitate 3D microbial community studies that are more clinically relevant and improve our understanding of biofilm-associated disease processes.</p> <p> </p>


2021 ◽  
Author(s):  
Alexandre Grimaldi ◽  
Glenda Evangelina Comai ◽  
Sebastien Mella ◽  
Shahragim Tajbakhsh

How distinct cell fates are manifested by direct lineage ancestry from bipotent progenitors, or by specification of individual cell types within a field of cells is a key question for understanding the emergence of tissues. The interplay between skeletal muscle progenitors and associated connective tissues cells provides a model for examining how muscle functional units are established. Most craniofacial structures originate from the vertebrate-specific neural crest cells except in the dorsal portion of the head, where they arise from cranial mesoderm. Here, using multiple lineage-traced single cell RNAseq, advanced computational methods and in situ analyses, we identify Myf5+ bipotent progenitors that give rise to both muscle and juxtaposed connective tissue. Following this bifurcation, muscle and connective tissue cells retain complementary signalling features and maintain spatial proximity. Interruption of upstream myogenic identity shifts muscle progenitors to a connective tissue fate. Interestingly, Myf5-derived connective tissue cells, which adopt a novel regulatory signature, were not observed in ventral craniofacial structures that are colonised by neural crest cells. Therefore, we propose that an ancestral program gives rise to bifated muscle and connective tissue cells in skeletal muscles that are deprived of neural crest.


2021 ◽  
Vol 22 (24) ◽  
pp. 13231
Author(s):  
Jon Egaña-Huguet ◽  
Edgar Soria-Gómez ◽  
Pedro Grandes

Epilepsy is one of the most common neurological conditions. Yearly, five million people are diagnosed with epileptic-related disorders. The neuroprotective and therapeutic effect of (endo)cannabinoid compounds has been extensively investigated in several models of epilepsy. Therefore, the study of specific cell-type-dependent mechanisms underlying cannabinoid effects is crucial to understanding epileptic disorders. It is estimated that about 100 billion neurons and a roughly equal number of glial cells co-exist in the human brain. The glial population is in charge of neuronal viability, and therefore, their participation in brain pathophysiology is crucial. Furthermore, glial malfunctioning occurs in a wide range of neurological disorders. However, little is known about the impact of the endocannabinoid system (ECS) regulation over glial cells, even less in pathological conditions such as epilepsy. In this review, we aim to compile the existing knowledge on the role of the ECS in different cell types, with a particular emphasis on glial cells and their impact on epilepsy. Thus, we propose that glial cells could be a novel target for cannabinoid agents for treating the etiology of epilepsy and managing seizure-like disorders.


Author(s):  
Robert S. Molday

Colloidal gold particles have become one of the most widely used markers to detect, localize and, in some cases, quantitate cell surface and intracellular antigens and receptors since their introduction as transmission electron microscopic (TFM) markers by Faulk and Taylor in 1971 and as scanning electron microscopic (SEM) markers by Horisberger et al. in 1975. This interest in colloidal gold markers for cell labeling is based on their versatile properties for detection under the electron microscope. Colloidal gold particles are highly electron-dense which enables them to be seen under the TEM in thin sections of heavily stained cells. They can be prepared in a wide range of highly uniform sizes for visualization at different magnifications and for multiple labeling studies. Under the SEM, gold particles emit a high quantity of secondary electrons, backscattered electrons and characteristic X-ray signals and as a result, with the appropriate detectors, they can be readily distinguished from cell surface structures having a similar morphological appearance. The successful application of colloidal gold particles as markers for TEM and SEM however requires (i) careful preparation and characterization of both the gold markers and the ligand (protein)-gold conjugates, (ii) utilization of specific labeling techniques employing necessary controls to confirm the specificity of labeling, and (iii) critical evaluation of results in relation to the conditions used in labeling. These aspects of gold labeling will be considered here. Additional information can be obtained from recent reviews dealing specifically with gold markers and more generally with cell labeling techniques.


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