Ultrastructure of the lophophoral tentacles in the genus Phoronis (Phoronida, Lophophorata)

1993 ◽  
Vol 71 (9) ◽  
pp. 1861-1868 ◽  
Author(s):  
F. Pardos ◽  
C. Roldán ◽  
J. Benito ◽  
A. Aguirre ◽  
I. Fernández
Keyword(s):  
Cell Types ◽  
Point Of View ◽  
Sensory Cells ◽  
Blood Capillary ◽  
Supporting Cells ◽  
Connective Tissue Layer ◽  
Hollow Structures ◽  
Building Activities ◽  
Abundance And Distribution ◽  
Epidermal Gland

The lophophoral tentacles of two phoronids, Phoronis psammophila and Phoronis hippocrepia, are described from an ultrastructural point of view. The tentacles are hollow structures, with an epidermis exhibiting supporting cells, sensory cells, and four types of gland cells, A, B1, B2, B3. The epidermis rests on a connective tissue layer, tubular in shape, enclosing a coelomic space lined by myoepithelial mesothelium (peritoneum). There is a single blood capillary in the tentacular coelomic cavity, attached to the frontal face of the tentacle, with contractile walls derived from the peritoneum. Both erythrocytes and amoebocyte-like cells occur inside the capillary. Differences between the tentacles of these two species and those of Phoronis australis, whose structure is already known, mainly concern the abundance and distribution of the epidermal gland cell types and are related to the burrowing and tube-building activities of these animals in different substrata.

scholarly journals Neuronal apoptosis: signal and cell diversity

1969 ◽  
Vol 40 (1) ◽  
pp. 124-133
Author(s):  
Lina Vanessa Becerra ◽  
Hernán José Pimienta
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Neuronal Response ◽  
Neuronal Cell ◽  
Cell Types ◽  
Point Of View ◽  
Trophic Factors ◽  
Cell Diversity ◽  
Apoptotic Pathways ◽  
The Brain

Programmed cell death occurs as a physiological process during development. In the brain and spinal cord this event determines the number and location of the different cell types. In adulthood, programmed cell death or apoptosis is more restricted but it may play a major role in different acute and chronic pathological entities. However, in contrast to other tissues where apoptosis has been widely documented from a morphological point of view, in the central nervous system complete anatomical evidence of apoptosis is scanty. In spite of this there is consensus about the activation of different signal systems associated to programmed cell death. In the present article we attempt to summarize the main apoptotic pathways so far identified in nervous tissue. Considering that apoptotic pathways are multiple, the neuronal cell types are highly diverse and specialized and that neuronal response to injury and survival depends upon tissue context, (i.e., preservation of connectivity, glial integrity and cell matrix, blood supply and trophic factors availability) what is relevant for the apoptotic process in a sector of the brain may not be important in another.

scholarly journals The development of the socio-cultural space of the coal-mining region as a factor of human resources retention

2021 ◽  
Vol 315 ◽  
pp. 04014
Author(s):  
Natalia Kostiuk ◽  
Tatiana Panina ◽  
Khash-Erdene Sambalkhundev
Keyword(s):  
Human Resources ◽  
Coal Mining ◽  
Coal Industry ◽  
Point Of View ◽  
Professional Activity ◽  
Sample Population ◽  
Cultural Space ◽  
Main Method ◽  
Mining Region ◽  
Building Activities

The article presents an analysis of the problem of human resource retention in the coal-mining region. It is emphasized that along with the factors of economic development it is advisable to take into account the socio-cultural needs and preferences of employees to ensure the preservation of human resources and the development of human capital on this basis. The article substantiates the need to rely on the actual socio-cultural needs of the subjects of professional activity when building activities for the development of the socio-cultural space of the coal-mining region. The article analyzes the implementation of strategic measures for the creation of the Siberian Cluster of Arts from the point of view of the development of the socio-cultural space of the region for the retention of human resources. The empirical part of the article is presented by the results of the study of socio-cultural needs, leisure preferences and the assessment of the attractiveness of the factors of living in Kuzbass by employees of the coal industry enterprises of the region. The sample population included 93 respondents living in the following cities: Kemerovo, Berezovskiy, Kiselevsk, Novokuznetsk, Polysaevo, and Prokopyevsk. The main method of collecting information was a survey conducted through GoogleForms. The analysis uses methods of mathematical statistics, quantitative and qualitative analysis of the results, and analysis of the significance of socio-cultural needs for the respondents.

Fine Structure of the Eye of a Nudibranch Mollusc, Hermissenda Crassicornis

1967 ◽  
Vol 2 (3) ◽  
pp. 349-358
Author(s):  
R. M. EAKIN ◽  
JANE A. WESTFALL ◽  
M. J. DENNIS
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Optic Nerve ◽  
Light And Electron Microscopy ◽  
The Other ◽  
Sensory Cells ◽  
Nerve Fibres ◽  
Supporting Cells ◽  
Small Bodies ◽  
Receptor Cells

The eye of a nudibranch, Hermissenda crassicornis, was studied by light and electron microscopy. Three kinds of cells were observed: large sensory cells, each bearing at one end an array of microvilli (rhabdomere) and at the other end an axon which leaves the eye by the optic nerve; large pigmented supporting cells; and small epithelial cells, mostly corneal. There are five sensory cells, and the same number of nerve fibres in the optic nerve. The receptor cells contain an abundance of small vesicles, 600-800 Å in diameter. The lens is a spheroidal mass of osmiophilic, finely granular material. A basal lamina and a capsule of connective tissue enclose the eye. In some animals the eye is ‘infected’ with very small bodies, 4-5 µ in diameter, thought to be symbionts.

Delta-Notch signalling and the patterning of sensory cell differentiation in the zebrafish ear: evidence from the mind bomb mutant

Development ◽  
1998 ◽  
Vol 125 (23) ◽  
pp. 4637-4644 ◽  
Author(s):  
C. Haddon ◽  
Y.J. Jiang ◽  
L. Smithers ◽  
J. Lewis
Keyword(s):  
Cell Differentiation ◽  
Lateral Inhibition ◽  
Hair Cells ◽  
Sensory Cell ◽  
Cell Types ◽  
Notch Signalling ◽  
Supporting Cells ◽  
Fine Grained ◽  
Mechanosensory Hair Cells ◽  
The Mind

Mechanosensory hair cells in the sensory patches of the vertebrate ear are interspersed among supporting cells, forming a fine-grained pattern of alternating cell types. Analogies with Drosophila mechanosensory bristle development suggest that this pattern could be generated through lateral inhibition mediated by Notch signalling. In the zebrafish ear rudiment, homologues of Notch are widely expressed, while the Delta homologues deltaA, deltaB and deltaD, coding for Notch ligands, are expressed in small numbers of cells in regions where hair cells are soon to differentiate. This suggests that the delta-expressing cells are nascent hair cells, in agreement with findings for Delta1 in the chick. According to the lateral inhibition hypothesis, the nascent hair cells, by expressing Delta protein, would inhibit their neighbours from becoming hair cells, forcing them to be supporting cells instead. The zebrafish mind bomb mutant has abnormalities in the central nervous system, somites, and elsewhere, diagnostic of a failure of Delta-Notch signalling: in the CNS, it shows a neurogenic phenotype accompanied by misregulated delta gene expression. Similar misregulation of delta; genes is seen in the ear, along with misregulation of a Serrate homologue, serrateB, coding for an alternative Notch ligand. Most dramatically, the sensory patches in the mind bomb ear consist solely of hair cells, which are produced in great excess and prematurely; at 36 hours post fertilization, there are more than ten times as many as normal, while supporting cells are absent. A twofold increase is seen in the number of otic neurons also. The findings are strong evidence that lateral inhibition mediated by Delta-Notch signalling controls the pattern of sensory cell differentiation in the ear.

scholarly journals Non–cell autonomous toxicity in neurodegenerative disorders: ALS and beyond

2009 ◽  
Vol 187 (6) ◽  
pp. 761-772 ◽  
Author(s):  
Hristelina Ilieva ◽  
Magdalini Polymenidou ◽  
Don W. Cleveland
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Neurodegenerative Disorders ◽  
Cell Types ◽  
Neuronal Dysfunction ◽  
Inherited Disease ◽  
Supporting Cells ◽  
Cerebellar Ataxias ◽  
Multiple Cell ◽  
Lateral Sclerosis ◽  
Human Neurodegenerative Disease

Selective degeneration and death of one or more classes of neurons is the defining feature of human neurodegenerative disease. Although traditionally viewed as diseases mainly affecting the most vulnerable neurons, in most instances of inherited disease the causative genes are widely—usually ubiquitously—expressed. Focusing on amyotrophic lateral sclerosis (ALS), especially disease caused by dominant mutations in Cu/Zn superoxide dismutase (SOD1), we review here the evidence that it is the convergence of damage developed within multiple cell types, including within neighboring nonneuronal supporting cells, which is crucial to neuronal dysfunction. Damage to a specific set of key partner cells as well as to vulnerable neurons may account for the selective susceptibility of neuronal subtypes in many human neurodegenerative diseases, including Huntington's disease (HD), Parkinson's disease (PD), prion disease, the spinal cerebellar ataxias (SCAs), and Alzheimer's disease (AD).

scholarly journals Non-neuronal expression of SARS-CoV-2 entry genes in the olfactory system suggests mechanisms underlying COVID-19-associated anosmia

2020 ◽  
Vol 6 (31) ◽  
pp. eabc5801 ◽  
Author(s):  
David H. Brann ◽  
Tatsuya Tsukahara ◽  
Caleb Weinreb ◽  
Marcela Lipovsek ◽  
Koen Van den Berge ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Neuronal Cell ◽  
Cell Types ◽  
Cell Entry ◽  
Common Symptom ◽  
Supporting Cells ◽  
Odor Perception ◽  
Sustentacular Cells ◽  
Human Olfactory Mucosa ◽  
Human Primate

Abstract:Altered olfactory function is a common symptom of COVID-19, but its etiology is unknown. A key question is whether SARS-CoV-2 (CoV-2) – the causal agent in COVID-19 – affects olfaction directly, by infecting olfactory sensory neurons or their targets in the olfactory bulb, or indirectly, through perturbation of supporting cells. Here we identify cell types in the olfactory epithelium and olfactory bulb that express SARS-CoV-2 cell entry molecules. Bulk sequencing demonstrated that mouse, non-human primate and human olfactory mucosa expresses two key genes involved in CoV-2 entry, ACE2 and TMPRSS2. However, single cell sequencing revealed that ACE2 is expressed in support cells, stem cells, and perivascular cells, rather than in neurons. Immunostaining confirmed these results and revealed pervasive expression of ACE2 protein in dorsally-located olfactory epithelial sustentacular cells and olfactory bulb pericytes in the mouse. These findings suggest that CoV-2 infection of non-neuronal cell types leads to anosmia and related disturbances in odor perception in COVID-19 patients.

Light microscopical and cytochemical study on the adhesive and epidermal gland cell secretions of the branchiobdellid Cambarincola fallax (Annelida: Clitellata)

1988 ◽  
Vol 66 (9) ◽  
pp. 2057-2064 ◽  
Author(s):  
S. R. Gelder ◽  
J. P. Rowe
Keyword(s):  
Basic Protein ◽  
Gland Cell ◽  
Attachment Site ◽  
Cell Types ◽  
The Body ◽  
Protein Component ◽  
Cell Type ◽  
Gland Cells ◽  
Adhesive Organs ◽  
Epidermal Gland

Eight types of gland cells are present in six different epidermal glands in the branchiobdellid Cambarincola fallax. The anterior and posterior adhesive organs are both composed of viscid and releaser adhesive gland cell types, and their secretions open onto the anterior attachment site on the ventral surface of the ventral peristomial lip and onto the posterior attachment disc, respectively. The secretion granules of the viscid gland cell type are composed of neutral mucosubstances with basic proteins containing arginine and (or) lysine; the releaser gland cell type contains basic proteinaceous granules with a tryptophan component. These adhesive glands are very similar to duo-gland adhesive organs described elsewhere. Use of the term "sucker" should be discontinued as there is no suctorial mechanism at the anterior attachment site and only circumstantial evidence of such action at the posterior disc. Two epidermal gland cell types occur together in groups of two to four cells at sites scattered over the body surface except in trunk segments 6 and 7. One of these epidermal gland cell types produces granular secretions formed of neutral mucosubstances with a basic protein component, and the other produces globular secretions composed of a carboxylated acid mucosubstance. Secretions from the peristomial gland cells open onto the dorsal and ventral lips. The posterolateral gland cells form three pairs: two pairs in segment 8 and one pair in segment 9. Both peristomial and posterolateral gland cells have granular secretions composed of neutral mucosubstances with a basic protein component. The two types of clitellar gland cells are arranged in groups of 7 to 13 cells with a granular secretion type predominating over one with globular secretions. The granular type consists of neutral mucosubstances with amyloid-like and strong basic protein components, and the globular type consists of a carboxylated acid mucosubstance with a nonbasic protein component.

scholarly journals The cell coat of the sensory and supporting cells of the rainbow trout saccular macula as demonstrated by reaction with ruthenium red and tannic acid.

1990 ◽  
Vol 38 (11) ◽  
pp. 1615-1623 ◽  
Author(s):  
K M Khan ◽  
J S Hatfield ◽  
D G Drescher
Keyword(s):  
Rainbow Trout ◽  
Tannic Acid ◽  
Ruthenium Red ◽  
Sensory Cells ◽  
Surface Coat ◽  
Basal Region ◽  
Apical Surface ◽  
Luminal Surface ◽  
Supporting Cells ◽  
Cell Coat

The surface of most cells is covered by glycoconjugates. The composition and thickness of the surface coat varies among different cell types. The purpose of the present study was to demonstrate the presence of and to characterize the cell coat surrounding the cells in the saccular macula of the rainbow trout. Tissues were fixed in Karnovsky's fixative containing either ruthenium red (0.5, 1, or 2%) or tannic acid (1, 2, or 4%). The apical surface of the sensory and supporting cells reacted with both agents. Varying the concentration of the compounds within a certain range did not significantly affect the degree of tissue staining. Whereas ruthenium red staining was distributed evenly along the luminal surface of the epithelium and along the length of the stereocilia, tannic acid formed electron-dense clumps on the luminal surface of sensory and non-sensory cells and in the basal region of the macular epithelium. The stereocilia of the sensory cells also exhibited tannic acid-positive, electrondense precipitate, particularly near the distal ends of these processes, while uniform staining of the plasma membrane was seen along their lengths. The results of this study suggest that the trout saccular macula is provided with extracellular microenvironments which may be necessary for functional integrity.

scholarly journals The effect of convection on infrared detection by antennal warm cells in the bloodsucking bug Rhodnius prolixus

2015 ◽  
Vol 113 (7) ◽  
pp. 2250-2261 ◽  
Author(s):  
Harald Tichy ◽  
Lydia M. Zopf
Keyword(s):  
Natural Convection ◽  
Thermal Effects ◽  
Cell Types ◽  
Infrared Detection ◽  
Sensory Cells ◽  
Ir Radiation ◽  
Cell Responses ◽  
Air Temperatures ◽  
Discharge Rates ◽  
Small Model

Previous work revealed that bloodsucking bugs can discriminate between oscillating changes in infrared (IR) radiation and air temperature (T) using two types of warm cells located in peg-in-pit sensilla and tapered hairs (Zopf LM, Lazzari CR, Tichy H. J Neurophysiol 111: 1341–1349, 2014). These two stimuli are encoded and discriminated by the response quotient of the two warm cell types. IR radiation stimulates the warm cell in the peg-in-pit sensillum more strongly than that in the tapered hair. T stimuli evoke the reverse responses; they stimulate the latter more strongly than the former. In nature, IR and T cues are always present with certain radiation intensities and air temperatures, here referred to as background IR radiation and background T. In this article, we found that the response quotient permits the discrimination of IR and T oscillations even in the presence of different backgrounds. We show that the two warm cells respond well to IR oscillations if the background T operates by natural convection but poorly at forced convection, even if the background T is higher than at natural convection. Background IR radiation strongly affects the responses to T oscillations: the discharge rates of both warm cells are higher the higher the power of the IR background. We compared the warm cell responses with the T measured inside small model objects shaped like a cylinder, a cone, or a disc. The experiments indicate that passive thermal effects of the sense organs rather than intrinsic properties of the sensory cells are responsible for the observed results.

scholarly journals Infrared detection without specialized infrared receptors in the bloodsucking bug Rhodnius prolixus

2014 ◽  
Vol 112 (7) ◽  
pp. 1606-1615 ◽  
Author(s):  
Lydia M. Zopf ◽  
Claudio R. Lazzari ◽  
Harald Tichy
Keyword(s):  
Paired Comparison ◽  
Cell Types ◽  
Response Strength ◽  
Oscillation Period ◽  
Rhodnius Prolixus ◽  
Infrared Detection ◽  
Sensory Cells ◽  
Neuronal Coding ◽  
Discharge Rates ◽  
The Difference

Bloodsucking bugs use infrared radiation (IR) for locating warm-blooded hosts and are able to differentiate between infrared and temperature (T) stimuli. This paper is concerned with the neuronal coding of IR in the bug Rhodnius prolixus. Data obtained are from the warm cells in the peg-in-pit sensilla (PSw cells) and in the tapered hairs (THw cells). Both warm cells responded to oscillating changes in air T and IR with oscillations in their discharge rates. The PSw cells produced stronger responses to T oscillations than the THw cells. Oscillations in IR did the reverse: they stimulated the latter more strongly than the former. The reversal in the relative excitability of the two warm cell types provides a criterion to distinguish between changes in T and IR. The existence of strongly responsive warm cells for one or the other stimulus in a paired comparison is the distinguishing feature of a “combinatory coding” mechanism. This mechanism enables the information provided by the difference or the ratio between the response magnitudes of both cell types to be utilized by the nervous system in the neural code for T and IR. These two coding parameters remained constant, although response strength changed when the oscillation period was altered. To discriminate between changes in T and IR, two things are important: which sensory cell responded to either stimulus and how strong was the response. The label warm or infrared cell may indicate its classification, but the functions are only given in the context of activity produced in parallel sensory cells.

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