Etude cytologique des organes photorécepteurs de la Planaire australienne Cura pinguis

1977 ◽  
Vol 55 (2) ◽  
pp. 381-390 ◽  
Author(s):  
Jacques P. Durand ◽  
Nicole Gourbault
Keyword(s):  
Light And Electron Microscopy ◽  
Morphological Characteristics ◽  
Cell Types ◽  
Pigment Cells ◽  
Cellular Activity ◽  
Visual Cells ◽  
Visual Processes ◽  
Eye Opening ◽  
Different Cell Types ◽  
The Brain

The photoreceptors of the australian planarian Cura pinguis were studied by light and electron microscopy. They consist of two different cell types (=primitive type), a cup of pigment cells, and 25 to 30 bipolar visual cells. Cytoplasmic extensions of the pigment cells close the eye opening but leave the dendritic stalk free. This study shows that the morphological characteristics suggest a metabolic cellular activity with the presence of components implied in the visual processes. In animals kept in the dark, the microvilli have a less regular appearance and some material accumulates in the spaces between the visual and pigment cells. The efferent innervation displays a narrow connection with the brain.

scholarly journals MiR-7 in Cancer Development

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 325
Author(s):  
Petra Korać ◽  
Mariastefania Antica ◽  
Maja Matulić
Keyword(s):  
Cell Fate ◽  
Dominant Role ◽  
Tumor Development ◽  
Mrna Translation ◽  
Cell Types ◽  
Fine Tuning ◽  
Non Coding Rna ◽  
Tumor Types ◽  
Different Cell Types ◽  
The Brain

MicroRNAs (miRNAs) are short non-coding RNA involved in the regulation of specific mRNA translation. They participate in cellular signaling circuits and can act as oncogenes in tumor development, so-called oncomirs, as well as tumor suppressors. miR-7 is an ancient miRNA involved in the fine-tuning of several signaling pathways, acting mainly as tumor suppressor. Through downregulation of PI3K and MAPK pathways, its dominant role is the suppression of proliferation and survival, stimulation of apoptosis and inhibition of migration. Besides these functions, it has numerous additional roles in the differentiation process of different cell types, protection from stress and chromatin remodulation. One of the most investigated tissues is the brain, where its downregulation is linked with glioblastoma cell proliferation. Its deregulation is found also in other tumor types, such as in liver, lung and pancreas. In some types of lung and oral carcinoma, it can act as oncomir. miR-7 roles in cell fate determination and maintenance of cell homeostasis are still to be discovered, as well as the possibilities of its use as a specific biotherapeutic.

Differential expression of glutamate receptor genes (GluR1-5) in the rat retina

1992 ◽  
Vol 8 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Thomas E. Hughes ◽  
Irm Hermans-Borgmeyer ◽  
Steve Heinemann
Keyword(s):  
Glutamate Receptor ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Inner Nuclear Layer ◽  
Dissociated Cells ◽  
Different Cell Types ◽  
The Brain ◽  
Overlapping Sets

AbstractThe recent isolation of at least five different cDNAs encoding functional subunits of glutamate receptors (GluR1 to GluR5) has revealed a diversity whose function is not understood. To learn more about how these different receptor subunits are used in the brain, we undertook an in situ hybridization study of the retina to define how the different glutamate receptor genes are expressed. We chose the retina because the glutamate sensitivities of its different cell types have been characterized, and these different neurons reside in different laminae.Hybridization of [35S]UTP-labeled cRNA probes with transverse sections and freshly dissociated cells reveals that all five receptor subunits are expressed in the retina. Hybridization signal is detected in different, but overlapping, sets of cells in the retina. GluR1, GluR2, and GluR5 are expressed by many somata, and GluR4 by a few, in the outer third of the inner nuclear layer, where the horizontal cells reside. Transcripts for GluR1, GluR2, and GluR5 are found in the somata within the middle third of the inner nuclear layer, which is where the bipolar cell somata are located, and GluR2 probes label freshly dissociated rod bipolar cells. All of the probes produce labeling over the cells at the inner edge of the inner nuclear layer, which are probably amacrine cells, as well as over the cell bodies in the ganglion cell layer.

scholarly journals A Rare Case of Third Ventricular Glioblastoma

2021 ◽  
Author(s):  
Asmira Gacic ◽  
Hakija Beculic ◽  
Rasim Skomorac ◽  
Alma Efendic
Keyword(s):  
Spinal Cord ◽  
Glioblastoma Multiforme ◽  
Blood Vessels ◽  
Rare Case ◽  
Third Ventricle ◽  
Cell Types ◽  
The Third ◽  
Different Cell Types ◽  
Brain And Spinal Cord ◽  
The Brain

Glioblastoma, also known as glioblastoma multiforme, is an aggressive type of cancer that is made up of abnormal astrocytic cells, but also contain a mixture of different cell types (including blood vessels) and areas of necrosis. It is often seen in the brain and spinal cord, but glioblastomas are rarely found in the third ventricle. In this case, it was diagnosed in a 22-year-old male patient and we intended to draw

scholarly journals S100A6 and Its Brain Ligands in Neurodegenerative Disorders

2020 ◽  
Vol 21 (11) ◽  
pp. 3979
Author(s):  
Anna Filipek ◽  
Wiesława Leśniak
Keyword(s):  
Mammalian Cells ◽  
Brain Structures ◽  
Cell Types ◽  
Cytoskeletal Organization ◽  
High Level ◽  
S100a6 Protein ◽  
Different Cell Types ◽  
The Brain ◽  
Lateral Sclerosis

The S100A6 protein is present in different mammalian cells and tissues including the brain. It binds Ca2+ and Zn2+ and interacts with many target proteins/ligands. The best characterized ligands of S100A6, expressed at high level in the brain, include CacyBP/SIP and Sgt1. Research concerning the functional role of S100A6 and these two ligands indicates that they are involved in various signaling pathways that regulate cell proliferation, differentiation, cytoskeletal organization, and others. In this review, we focused on the expression/localization of these proteins in the brain and on their possible role in neurodegenerative diseases. Published results demonstrate that S100A6, CacyBP/SIP, and Sgt1 are expressed in various brain structures and in the spinal cord and can be found in different cell types including neurons and astrocytes. When it comes to their possible involvement in nervous system pathology, it is evident that their expression/level and/or subcellular localization is changed when compared to normal conditions. Among diseases in which such changes have been observed are Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), epileptogenesis, Parkinson’s disease (PD), Huntington’s disease (HD), and others.

Comparative ultrastructure of methanogenic bacteria

1975 ◽  
Vol 21 (2) ◽  
pp. 121-129 ◽  
Author(s):  
J. G. Zeikus ◽  
V. G. Bowen
Keyword(s):  
Morphological Characteristics ◽  
Cell Types ◽  
Methanogenic Bacteria ◽  
Diverse Group ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Intracytoplasmic Membranes ◽  
Microscopic Studies ◽  
Different Cell Types ◽  
Comparative Ultrastructure

Electron-microscopic studies using thin sections revealed that methane-producing bacteria were an ultrastructurally diverse group. Fine structure and morphological characteristics separated these bacteria into four discrete cell types. Methanogenic bacteria displayed a gram-positive cell wall that varied considerably among different cell types. Differences in granular inclusions, reserve materials, and intracytoplasmic membranes were observed. Unique ultrastructural features were not shared by all methanogenic species studied.

scholarly journals A Cluster of Four Surface Antigen Genes Specifically Expressed in Bradyzoites, SAG2CDXY, Plays an Important Role in Toxoplasma gondii Persistence

2008 ◽  
Vol 76 (6) ◽  
pp. 2402-2410 ◽  
Author(s):  
Jeroen P. J. Saeij ◽  
Gustavo Arrizabalaga ◽  
John C. Boothroyd
Keyword(s):  
Toxoplasma Gondii ◽  
Surface Antigen ◽  
Chronic Infection ◽  
Cell Types ◽  
Firefly Luciferase ◽  
Specific Expression ◽  
Genes Encoding ◽  
Tandem Genes ◽  
Different Cell Types ◽  
The Brain

ABSTRACT Toxoplasma gondii is one of the most successful protozoan parasites of warm-blooded animals. Stage-specific expression of its surface molecules is thought to be key to its ability to establish chronic infection in immunocompetent animals. The rapidly dividing tachyzoite stage displays a different subset of family of surface antigen 1 (SAG1)-related sequences (SRSs) from that displayed by the encysted bradyzoite stage. It is possible that this switch is necessary to protect the bradyzoites against an immune response raised against the tachyzoite stage. Alternatively, it might be that bradyzoite SRSs evolved to facilitate invasion of different cell types, such as those found in the brain, where cysts develop, or the small intestine, where bradyzoites must enter after oral infection. Here we studied the function of a cluster of four tandem genes, encoding bradyzoite SRSs called SAG2C, -D, -X, and -Y. Using bioluminescence imaging of mice infected with parasites expressing firefly luciferase (FLUC) driven by the SAG2D promoter, we show stage conversion for the first time in living animals. A truncated version of the SAG2D promoter (SAG2Dmin) gave efficient expression of FLUC in both tachyzoites and bradyzoites, indicating that the bradyzoite specificity of the complete SAG2D promoter is likely due to an element(s) that normally suppresses expression in tachyzoites. Comparing mice infected with the wild type or a mutant where the SAG2CDXY cluster of genes has been deleted (ΔSAG2CDXY), we demonstrate that whereas ΔSAG2CDXY parasites are less capable of maintaining a chronic infection in the brain, they do not show a defect in oral infectivity.

scholarly journals Polyomavirus JC in the Context of Immunosuppression: A Series of Adaptive, DNA Replication-Driven Recombination Events in the Development of Progressive Multifocal Leukoencephalopathy

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Edward M. Johnson ◽  
Margaret J. Wortman ◽  
Ayuna V. Dagdanova ◽  
Patric S. Lundberg ◽  
Dianne C. Daniel
Keyword(s):  
Dna Replication ◽  
Progressive Multifocal Leukoencephalopathy ◽  
Cell Types ◽  
Lymphoid Cells ◽  
Replication Forks ◽  
Polyomavirus Jc ◽  
Noncoding Control Region ◽  
Different Cell Types ◽  
The Brain ◽  
Primary Tissue

Polyomavirus JC (JCV) is the etiological agent of progressive multifocal leukoencephalopathy (PML), a demyelinating infection of oligodendrocytes in the brain. PML, a frequently fatal opportunistic infection in AIDS, has also emerged as a consequence of treatment with several new immunosuppressive therapeutic agents. Although nearly 80% of adults are seropositive, JCV attains an ability to infect glial cells in only a minority of people. Data suggest that JCV undergoes sequence alterations that accompany this ability, and these changes can be derived from an archetype strain by mutation, deletion, and duplication. While the introductory source and primary tissue reservoir of JCV remain unknown, lymphoid cells have been identified as potential intermediaries in progression of JCV to the brain. This review is focused on sequence changes in the noncoding control region (NCCR) of the virus. We propose an adaptive mechanism that involves a sequential series of DNA replication-driven NCCR recombination events involving stalled DNA replication forks at NCCR palindromic secondary structures. We shall describe how the NCCR sequence changes point to a model in which viral DNA replication drives NCCR recombination, allowing JCV adaptation to different cell types in its progression to neurovirulence.

Neuronal Diversity In The Retina

e-Neuroforum ◽  
2017 ◽  
Vol 23 (2) ◽  
Author(s):  
Philipp Berens ◽  
Thomas Euler
Keyword(s):  
Building Blocks ◽  
Cell Types ◽  
Relevant Information ◽  
Future Research ◽  
Neuronal Diversity ◽  
Form Complex ◽  
Current State ◽  
Complex Circuits ◽  
Different Cell Types ◽  
The Brain

AbstractThe retina in the eye performs complex computations, to transmit only behaviourally relevant information about our visual environment to the brain. These computations are implemented by numerous different cell types that form complex circuits. New experimental and computational methods make it possible to study the cellular diversity of the retina in detail – the goal of obtaining a complete list of all the cell types in the retina and, thus, its “building blocks”, is within reach. We review the current state of this endeavour and highlight possible directions for future research.

scholarly journals Regenerative Neurology and Regenerative Cardiology: Shared Hurdles and Achievements

2022 ◽  
Vol 23 (2) ◽  
pp. 855
Author(s):  
Dinko Mitrečić ◽  
Valentina Hribljan ◽  
Denis Jagečić ◽  
Jasmina Isaković ◽  
Federica Lamberto ◽  
...  
Keyword(s):  
Biomedical Research ◽  
Cell Types ◽  
In Vitro Models ◽  
Medical Systems ◽  
Heart Infarction ◽  
Affected Tissue ◽  
In Vitro Systems ◽  
Different Cell Types ◽  
The Brain

From the first success in cultivation of cells in vitro, it became clear that developing cell and/or tissue specific cultures would open a myriad of new opportunities for medical research. Expertise in various in vitro models has been developing over decades, so nowadays we benefit from highly specific in vitro systems imitating every organ of the human body. Moreover, obtaining sufficient number of standardized cells allows for cell transplantation approach with the goal of improving the regeneration of injured/disease affected tissue. However, different cell types bring different needs and place various types of hurdles on the path of regenerative neurology and regenerative cardiology. In this review, written by European experts gathered in Cost European action dedicated to neurology and cardiology-Bioneca, we present the experience acquired by working on two rather different organs: the brain and the heart. When taken into account that diseases of these two organs, mostly ischemic in their nature (stroke and heart infarction), bring by far the largest burden of the medical systems around Europe, it is not surprising that in vitro models of nervous and heart muscle tissue were in the focus of biomedical research in the last decades. In this review we describe and discuss hurdles which still impair further progress of regenerative neurology and cardiology and we detect those ones which are common to both fields and some, which are field-specific. With the goal to elucidate strategies which might be shared between regenerative neurology and cardiology we discuss methodological solutions which can help each of the fields to accelerate their development.

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