Anatomy and ultrastructure of the endophytic system of Pilostyles thurberi (Rafflesiaceae)

1985 ◽  
Vol 63 (7) ◽  
pp. 1231-1240 ◽  
Author(s):  
Job Kuijt ◽  
D. Bray ◽  
A. R. Olson
Keyword(s):  
Cell Types ◽  
Sieve Element ◽  
Cell Type ◽  
Discontinuous System ◽  
Sieve Elements ◽  
The Third ◽  
Sieve Plates ◽  
Host Parasite ◽  
Anatomy And Ultrastructure ◽  
Sieve Pores

The endophytic system of Pilostyles thurberi Gray consists of initially uniseriate filaments which develop into an anastomosing complex of larger cortical strands and radial sinkers. In the cortical strands three cell types are recognized, two of which differ largely in the density of the cytoplasm, the shape of the nucleus, and the degree to which the cytoplasm becomes plasmolyzed during fixation. The nuclei of both cell types contain two nucleoli which are physically connected by a nucleolar bridge. The third cell type demonstrates sieve plates, including a calloselike substance in the sieve pores and is consequently considered to be a sieve element. The sieve elements appear to form a discontinuous system and are regarded as a vestigial cell type. Plasmodesmal connections across the host–parasite interface have not been observed.

scholarly journals A crystalline inclusion in sieve element nuclei of Amsinckia. II. The inclusion in maturing cells

1979 ◽  
Vol 38 (1) ◽  
pp. 11-22
Author(s):  
K. Esau ◽  
A.C. Magyarosy
Keyword(s):  
Hydrostatic Pressure ◽  
Sieve Element ◽  
Crystalline Inclusion ◽  
Sieve Elements ◽  
P Protein ◽  
Sudden Release ◽  
Sieve Plates ◽  
Tubular Components

The compounds crystalloids formed in sieve element nuclei of Amsinckia douglasiana A. DC. (Boraginaceae) during differentiation of the cell become disaggregated during the nuclear breakdown characteristic of a maturing sieve element. The phenomenon occurs in both healthy and virus-infected plants. The crystalloid component termed cy, which is loosely aggregated, separates from the densely aggregated component termed cx and disperses. The cx component may become fragmented, or broken into large pieces, or remain intact after the cell matures. After their release from the nucleus both crystalloid components become spatially associated with the dispersed P-protein originating in the cytoplasm, but remain distinguishable from it. The component tubules of P-protein are hexagonal in transections and are somewhat wider than the 6-sided cy tubules. The cx tubules are much narrower than the P-protein or the cy tubules and have square transections. Both the P-protein and the products of disintegrated crystalloids accumulate at sieve plates in sieve elements subjected to sudden release of hydrostatic pressure by cutting the phloem. The question of categorizing the tubular components of the nuclear crystalloid of a sieve element with reference to the concept of P-protein is discussed.

Fine structure of the phloem of Pisum sativum. I. The sieve element ontogeny

1965 ◽  
Vol 13 (2) ◽  
pp. 171 ◽  
Author(s):  
MC Wark ◽  
TC Chambers
Keyword(s):  
Endoplasmic Reticulum ◽  
Pisum Sativum ◽  
Nuclear Material ◽  
Sieve Element ◽  
Secondary Phloem ◽  
Sieve Elements ◽  
Pisum Sativum L ◽  
Ontogenetic Study ◽  
Sieve Plates ◽  
Peripheral Cytoplasm

An ontogenetic study of secondary phloem sieve elements of Pisum sativum L., fixed on the intact plant for electron microscopy, indicates that the connecting strands across the sieve plates are continuities of the endoplasmic reticulum. Each connecting strand is surrounded by a callose cylinder. The peripheral cytoplasm of the nucleate "young" sieve elements contains longitudinally oriented tubules of endoplasmic reticulum. As the sieve elements develop, nuclear material is extruded into the cytoplasm by way of a fibrotubular body which is structurally distinct from the slime body. When the cells are fully expanded the slime bodies disperse. This process is followed by breakdown of a number of organelles including the nucleus and tonoplast. This apparently leaves the endoplasmic reticulum free in the cell lumen.

scholarly journals Structural differences between plasma-membrane 5′-nucleotidase in different cell types as evidenced by antibodies

1985 ◽  
Vol 232 (3) ◽  
pp. 859-862 ◽  
Author(s):  
J Harb ◽  
K Meflah ◽  
S Bernard
Keyword(s):  
Cell Types ◽  
Antigenic Determinants ◽  
Nucleotidase Activity ◽  
Cell Type ◽  
Caudate Nuclei ◽  
The Third ◽  
Common Structure ◽  
Structural Differences ◽  
Structural Nature ◽  
Different Cell Types

Antibodies raised against bovine 5′-nucleotidase inhibit this enzyme as well as 5′-nucleotidase from other bovine tissues, showing common structure(s) between these proteins. However, an IgG fraction directed against the glucidic moiety of the liver enzyme did not cross-react with the enzyme from lymphocyte or caudate nuclei, a clear indication that within the same species the 5′-nucleotidase differs from one cell type to another. In addition, immunoblots after electrophoresis show that the previous antibodies recognize 5′-nucleotidase from human, mouse or chicken origin. However, only human 5′-nucleotidase activity can be inhibited by the antibodies. Thus at least three groups of antigenic determinants must exist on the 5′-nucleotidase: one related to the glucidic moiety of the glycoprotein whose binding inhibits the enzyme activity, another related to the catalytic site, as its binding also led to enzyme inhibition, and a last one of structural nature. It seems that the third group of determinant is common to many species, whereas the second one is more restricted.

Selective staining of secretory granules of adrenal medullary cells by silver methenamine: A light and electron microscopic study

1968 ◽  
Vol 46 (5) ◽  
pp. 745-747 ◽  
Author(s):  
William W. L. Chang ◽  
Sergio A. Bencosme
Keyword(s):  
Microscopic Study ◽  
Adrenal Medulla ◽  
Electron Microscopic Study ◽  
Secretory Granules ◽  
Cell Types ◽  
Cell Type ◽  
Glutaraldehyde Fixation ◽  
Electron Microscopic ◽  
Selective Staining ◽  
The Third

A reevaluation of the silver methenamine reaction as an electron stain has ensued from recent use of glutaraldehyde fixation alone. By this technique, three cell types of rat adrenal medulla were found: (i) the norepinephrine-containing cells showed selectively stained, irregular, black granules; (ii) the epinephrine-containing cells showed round, light-grey granules; and (iii) the third cell type showed round granules like those of epinephrine-containing cells, but black in color, similar to those of the norepinephrine-containing cells.

scholarly journals A STUDY OF SIEVE ELEMENT STARCH USING SEQUENTIAL ENZYMATIC DIGESTION AND ELECTRON MICROSCOPY

1970 ◽  
Vol 45 (2) ◽  
pp. 383-398 ◽  
Author(s):  
Barry A. Palevitz ◽  
Eldon H. Newcomb
Keyword(s):  
Electron Microscopy ◽  
Sieve Tube ◽  
Cell Types ◽  
Enzymatic Digestion ◽  
Sieve Element ◽  
Branch Points ◽  
Thin Sections ◽  
Sieve Elements ◽  
Hypocotyl Tissue ◽  
Bare Copper

The fine structure of plastids and their starch deposits in differentiating sieve elements was studied in bean (Phaseolus vulgaris L.). Ultrastructural cytochemistry employing two carbohydrases specific for different linkages was then used to compare the chemical nature of "sieve tube starch" (the starch deposited in sieve elements) with that of the ordinary starch of other cell types. Hypocotyl tissue from seedlings was fixed in glutaraldehyde, postfixed in osmium tetroxide, and embedded in Epon-Araldite. Treatment of thin sections on uncoated copper grids with α-amylase or diastase at pH 6.8 to cleave α-(1 → 4) bonds resulted in digestion of ordinary starch grains but not sieve element grains, as determined by electron microscopy. Since α-(1 → 6) branch points in amylopectin-type starches make the adjacent α-(1 → 4) linkages somewhat resistant to hydrolysis by α-amylase, other sections mounted on bare copper or gold grids were treated with pullulanase (a bacterial α-[1 → 6] glucosidase) prior to digestion with diastase. Pullulanase did not digest sieve element starch, but rendered the starch digestible subsequently by α-amylase. Diastase followed by pullulanase did not result in digestion. The results provide evidence that sieve element starch is composed of highly branched molecules with numerous α-(1 → 6) linkages.

Dendritic cells of the human epidermis: immuno-electron microscopic studies of la antigen reactivity

1978 ◽  
Vol 36 (2) ◽  
pp. 644-645
Author(s):  
G. Rowden ◽  
M. G. Lewis ◽  
T. M. Phillips
Keyword(s):  
Dendritic Cells ◽  
Langerhans Cells ◽  
Cell Types ◽  
Cell Type ◽  
Electron Microscopic ◽  
La Antigen ◽  
Microscopic Studies ◽  
A Cell ◽  
C3 Receptors ◽  
Antigen Reactivity

Langerhans cells of mammalian stratified squamous epithelial have proven to be an enigma since their discovery in 1868. These dendritic suprabasal cells have been considered as related to melanocytes either as effete cells, or as post divisional products. Although grafting experiments seemed to demonstrate the independence of the cell types, much confusion still exists. The presence in the epidermis of a cell type with morphological features seemingly shared by melanocytes and Langerhans cells has been especially troublesome. This so called "indeterminate", or " -dendritic cell" lacks both Langerhans cells granules and melanosomes, yet it is clearly not a keratinocyte. Suggestions have been made that it is related to either Langerhans cells or melanocyte. Recent studies have unequivocally demonstrated that Langerhans cells are independent cells with immune function. They display Fc and C3 receptors on their surface as well as la (immune region associated) antigens.

scholarly journals Fibroblasts Influence the Efficacy, Resistance, and Future Use of Vaccines and Immunotherapy in Cancer Treatment

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 634
Author(s):  
Bailee H. Sliker ◽  
Paul M. Campbell
Keyword(s):  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Cell Types ◽  
Fibroblast Activation Protein ◽  
Cancer Associated Fibroblasts ◽  
Cell Type ◽  
Adaptive Immune ◽  
Adaptive Immune Cells ◽  
New Research ◽  
Tumor Types

Tumors are composed of not only epithelial cells but also many other cell types that contribute to the tumor microenvironment (TME). Within this space, cancer-associated fibroblasts (CAFs) are a prominent cell type, and these cells are connected to an increase in tumor progression as well as alteration of the immune landscape present in and around the tumor. This is accomplished in part by their ability to alter the presence of both innate and adaptive immune cells as well as the release of various chemokines and cytokines, together leading to a more immunosuppressive TME. Furthermore, new research implicates CAFs as players in immunotherapy response in many different tumor types, typically by blunting their efficacy. Fibroblast activation protein (FAP) and transforming growth factor β (TGF-β), two major CAF proteins, are associated with the outcome of different immunotherapies and, additionally, have become new targets themselves for immune-based strategies directed at CAFs. This review will focus on CAFs and how they alter the immune landscape within tumors, how this affects response to current immunotherapy treatments, and how immune-based treatments are currently being harnessed to target the CAF population itself.

scholarly journals Epigenetic reprogramming of cell identity: lessons from development for regenerative medicine

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Amitava Basu ◽  
Vijay K. Tiwari
Keyword(s):  
Regenerative Medicine ◽  
Cell Types ◽  
Direct Conversion ◽  
Cellular Reprogramming ◽  
Specific Cell ◽  
Cell Type ◽  
Pathological Conditions ◽  
Gene Regulatory ◽  
Induced Pluripotent ◽  
And Function

AbstractEpigenetic mechanisms are known to define cell-type identity and function. Hence, reprogramming of one cell type into another essentially requires a rewiring of the underlying epigenome. Cellular reprogramming can convert somatic cells to induced pluripotent stem cells (iPSCs) that can be directed to differentiate to specific cell types. Trans-differentiation or direct reprogramming, on the other hand, involves the direct conversion of one cell type into another. In this review, we highlight how gene regulatory mechanisms identified to be critical for developmental processes were successfully used for cellular reprogramming of various cell types. We also discuss how the therapeutic use of the reprogrammed cells is beginning to revolutionize the field of regenerative medicine particularly in the repair and regeneration of damaged tissue and organs arising from pathological conditions or accidents. Lastly, we highlight some key challenges hindering the application of cellular reprogramming for therapeutic purposes.

scholarly journals Connectivity characterization of the mouse basolateral amygdalar complex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Houri Hintiryan ◽  
Ian Bowman ◽  
David L. Johnson ◽  
Laura Korobkova ◽  
Muye Zhu ◽  
...  
Keyword(s):  
Granular Cell ◽  
Cell Types ◽  
Projection Neurons ◽  
Cell Type ◽  
Connectivity Map ◽  
Analysis Techniques ◽  
Domain Specific ◽  
Cell Type Specific ◽  
Unique Domain

AbstractThe basolateral amygdalar complex (BLA) is implicated in behaviors ranging from fear acquisition to addiction. Optogenetic methods have enabled the association of circuit-specific functions to uniquely connected BLA cell types. Thus, a systematic and detailed connectivity profile of BLA projection neurons to inform granular, cell type-specific interrogations is warranted. Here, we apply machine-learning based computational and informatics analysis techniques to the results of circuit-tracing experiments to create a foundational, comprehensive BLA connectivity map. The analyses identify three distinct domains within the anterior BLA (BLAa) that house target-specific projection neurons with distinguishable morphological features. We identify brain-wide targets of projection neurons in the three BLAa domains, as well as in the posterior BLA, ventral BLA, posterior basomedial, and lateral amygdalar nuclei. Inputs to each nucleus also are identified via retrograde tracing. The data suggests that connectionally unique, domain-specific BLAa neurons are associated with distinct behavior networks.

scholarly journals Shisa6 mediates cell-type specific regulation of depression in the nucleus accumbens

2021 ◽  
Author(s):  
Hee-Dae Kim ◽  
Jing Wei ◽  
Tanessa Call ◽  
Nicole Teru Quintus ◽  
Alexander J. Summers ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Current Treatment ◽  
Specific Cell ◽  
Excitatory Synapses ◽  
Cell Type ◽  
Cell Type Specific ◽  
Specific Regulation ◽  
Circuit Function

AbstractDepression is the leading cause of disability and produces enormous health and economic burdens. Current treatment approaches for depression are largely ineffective and leave more than 50% of patients symptomatic, mainly because of non-selective and broad action of antidepressants. Thus, there is an urgent need to design and develop novel therapeutics to treat depression. Given the heterogeneity and complexity of the brain, identification of molecular mechanisms within specific cell-types responsible for producing depression-like behaviors will advance development of therapies. In the reward circuitry, the nucleus accumbens (NAc) is a key brain region of depression pathophysiology, possibly based on differential activity of D1- or D2- medium spiny neurons (MSNs). Here we report a circuit- and cell-type specific molecular target for depression, Shisa6, recently defined as an AMPAR component, which is increased only in D1-MSNs in the NAc of susceptible mice. Using the Ribotag approach, we dissected the transcriptional profile of D1- and D2-MSNs by RNA sequencing following a mouse model of depression, chronic social defeat stress (CSDS). Bioinformatic analyses identified cell-type specific genes that may contribute to the pathogenesis of depression, including Shisa6. We found selective optogenetic activation of the ventral tegmental area (VTA) to NAc circuit increases Shisa6 expression in D1-MSNs. Shisa6 is specifically located in excitatory synapses of D1-MSNs and increases excitability of neurons, which promotes anxiety- and depression-like behaviors in mice. Cell-type and circuit-specific action of Shisa6, which directly modulates excitatory synapses that convey aversive information, identifies the protein as a potential rapid-antidepressant target for aberrant circuit function in depression.

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