scholarly journals The Mechanism of Secretion by the Salivary Gland of the Cockroach Periplaneta Americana (L.)

1951 ◽  
Vol 4 (2) ◽  
pp. 136 ◽  
Author(s):  
MF Day
Keyword(s):  
Salivary Gland ◽  
Periplaneta Americana ◽  
Cell Types ◽  
Main Cell ◽  
Secretory Ducts

The two main cell types of the cockroach salivary gland, the ductule-containing cells and the zymogenic cells, are together responsible for the secretion of a powerful amylase and a mucoid substance. The evidence presented suggests that the precursors of both these materials are elaborated in the zymogenic cells and are passed to the ductule-containing cells for excretion. The morphology of the secretory ducts suggests that they also play a part in the elaboration of the saliva.

scholarly journals Dramatic nucleolar dispersion in the salivary gland of Schwenkfeldina sp. (Diptera: Sciaridae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Mariano Amabis ◽  
Eduardo Gorab
Keyword(s):  
Salivary Gland ◽  
Transcriptional Activity ◽  
Relative Proportion ◽  
Extreme Case ◽  
Cell Types ◽  
Chromosome Length ◽  
Chromosomal Distribution ◽  
Dna And Rna ◽  
Polytene Nuclei ◽  
Chromosome Regions

AbstractMicronucleoli are among the structures composing the peculiar scenario of the nucleolus in salivary gland nuclei of dipterans representative of Sciaridae. Micronucleolar bodies contain ribosomal DNA and RNA, are transcriptionally active and may appear free in the nucleoplasm or associated with specific chromosome regions in salivary gland nuclei. This report deals with an extreme case of nucleolar fragmentation/dispersion detected in the salivary gland of Schwenkfeldina sp. Such a phenomenon in this species was found to be restricted to cell types undergoing polyteny and seems to be differentially controlled according to the cell type. Furthermore, transcriptional activity was detected in virtually all the micronucleolar bodies generated in the salivary gland. The relative proportion of the rDNA in polytene and diploid tissues showed that rDNA under-replication did not occur in polytene nuclei suggesting that the nucleolar and concomitant rDNA dispersion in Schwenkfeldina sp. may reflect a previously hypothesised process in order to counterbalance the rDNA loss due to the under-replication. The chromosomal distribution of epigenetic markers for the heterochromatin agreed with early cytological observations in this species suggesting that heterochromatin is spread throughout the chromosome length of Schwenkfeldina sp. A comparison made with results from another sciarid species argues for a role played by the heterochromatin in the establishment of the rDNA topology in polytene nuclei of Sciaridae.

scholarly journals The evolving definition of salivary gland stem cells

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Cecilia Rocchi ◽  
Lara Barazzuol ◽  
Rob P. Coppes
Keyword(s):  
Stem Cells ◽  
Salivary Gland ◽  
Adult Stem Cell ◽  
Cell Types ◽  
Research Field ◽  
New Therapeutic Approaches ◽  
Recent Developments ◽  
Radiation Induced ◽  
Definition Of

AbstractDysfunction of the salivary gland and irreversible hyposalivation are the main side effects of radiotherapy treatment for head and neck cancer leading to a drastic decrease of the quality of life of the patients. Approaches aimed at regenerating damaged salivary glands have been proposed as means to provide long-term restoration of tissue function in the affected patients. In studies to elucidate salivary gland regenerative mechanisms, more and more evidence suggests that salivary gland stem/progenitor cell behavior, like many other adult tissues, does not follow that of the hard-wired professional stem cells of the hematopoietic system. In this review, we provide evidence showing that several cell types within the salivary gland epithelium can serve as stem/progenitor-like cells. While these cell populations seem to function mostly as lineage-restricted progenitors during homeostasis, we indicate that upon damage specific plasticity mechanisms might be activated to take part in regeneration of the tissue. In light of these insights, we provide an overview of how recent developments in the adult stem cell research field are changing our thinking of the definition of salivary gland stem cells and their potential plasticity upon damage. These new perspectives may have important implications on the development of new therapeutic approaches to rescue radiation-induced hyposalivation.

scholarly journals The dynamic changes of main cell types in the microenvironment of sciatic nerves following sciatic nerve injury and the influence of let-7 on their distribution

RSC Advances ◽  
2018 ◽  
Vol 8 (72) ◽  
pp. 41181-41191 ◽  
Author(s):  
Tianmei Qian ◽  
Pan Wang ◽  
Qianqian Chen ◽  
Sheng Yi ◽  
Qianyan Liu ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Cell Types ◽  
Sciatic Nerve Injury ◽  
Dynamic Changes ◽  
Main Cell ◽  
Sciatic Nerves

Schwann cells (SCs), fibroblasts and macrophages are the main cells in the peripheral nerve stumps.

scholarly journals Cell therapy for cartilage repair

2021 ◽  
Author(s):  
Charlotte H. Hulme ◽  
Jade Perry ◽  
Helen S. McCarthy ◽  
Karina T. Wright ◽  
Martyn Snow ◽  
...  
Keyword(s):  
Cell Therapy ◽  
Stromal Cells ◽  
Therapeutic Agent ◽  
Cell Types ◽  
Therapeutic Agents ◽  
Osteochondral Defects ◽  
Main Cell ◽  
Great Hope ◽  
Additional Costs ◽  
Pharmaceutical Agents

Regenerative medicine, using cells as therapeutic agents for the repair or regeneration of tissues and organs, offers great hope for the future of medicine. Cell therapy for treating defects in articular cartilage has been an exemplar of translating this technology to the clinic, but it is not without its challenges. These include applying regulations, which were designed for pharmaceutical agents, to living cells. In addition, using autologous cells as the therapeutic agent brings additional costs and logistical challenges compared with using allogeneic cells. The main cell types used in treating chondral or osteochondral defects in joints to date are chondrocytes and mesenchymal stromal cells derived from various sources such as bone marrow, adipose tissue or umbilical cord. This review discusses some of their biology and pre-clinical studies before describing the most pertinent clinical trials in this area.

scholarly journals Minireview: Transcriptional Regulation of Gonadal Development and Differentiation

Endocrinology ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 1035-1042 ◽  
Author(s):  
Susan Y. Park ◽  
J. Larry Jameson
Keyword(s):  
Germ Cells ◽  
Sertoli Cells ◽  
Leydig Cells ◽  
Cell Types ◽  
Gonadal Development ◽  
Targeted Mutagenesis ◽  
Seminiferous Tubules ◽  
Molecular Pathways ◽  
Theca Cells ◽  
Main Cell

The embryonic gonad is undifferentiated in males and females until a critical stage when the sex chromosomes dictate its development as a testis or ovary. This binary developmental process provides a unique opportunity to delineate the molecular pathways that lead to distinctly different tissues. The testis comprises three main cell types: Sertoli cells, Leydig cells, and germ cells. The Sertoli cells and germ cells reside in seminiferous tubules where spermatogenesis occurs. The Leydig cells populate the interstitial compartment and produce testosterone. The ovary also comprises three main cell types: granulosa cells, theca cells, and oocytes. The oocytes are surrounded by granulosa and theca cells in follicles that grow and differentiate during characteristic reproductive cycles. In this review, we summarize the molecular pathways that regulate the distinct differentiation of these cell types in the developing testis and ovary. In particular, we focus on the transcription factors that initiate these cascades. Although most of the early insights into the sex determination pathway were based on human mutations, targeted mutagenesis in mouse models has revealed key roles for genes not anticipated to regulate gonadal development. Defining these molecular pathways provides the foundation for understanding this critical developmental event and provides new insight into the causes of gonadal dysgenesis.

scholarly journals Current Status of Histogenetic and Morphogenetic Concepts of Salivary Gland Tumorigenesis

1993 ◽  
Vol 4 (5) ◽  
pp. 639-677 ◽  
Author(s):  
Irving Dardick ◽  
Aileen P. Burford-Mason
Keyword(s):  
Salivary Gland ◽  
Acinar Cells ◽  
Neoplastic Transformation ◽  
Cell Types ◽  
Salivary Gland Tumors ◽  
Current Status ◽  
Normal Gland ◽  
Routine Diagnosis ◽  
Diagnosis And Classification

Because of their complexity and relative infrequency, salivary gland tumors commonly result in diagnostic problems. Histogenetic and morphogenetic concepts of tumorigenesis in these glands are reviewed and their relevance to routine diagnosis and classification of salivary gland tumors evaluated. Evidence is presented from animal and human studies that under steady-state and pathophysiological conditions, all cell types present in the normal gland, including acinar cells, are capable of rapidly entering the cell cycle and are, therefore, possible targets for neoplastic transformation.

scholarly journals Histochemical localisation of carbonic anhydrase in the digestive tract and salivary glands of the house cricket, Acheta domesticus

2020 ◽  
Vol 6 (2) ◽  
pp. 191-198
Author(s):  
E. Thorsson ◽  
A. Jansson ◽  
M. Vaga ◽  
L. Holm
Keyword(s):  
Carbonic Anhydrase ◽  
Salivary Glands ◽  
Digestive Tract ◽  
Cell Types ◽  
Acheta Domesticus ◽  
Ph Gradient ◽  
House Cricket ◽  
Main Cell ◽  
Cellular Localisation ◽  
Luminal Ph

The house cricket (Acheta domesticus) is one of several cricket species with great potential to be farmed as a sustainable protein source. In order to succeed in large-scale cricket farming, knowledge of cricket digestion is essential. The digestive tract morphology of A. domesticus is well documented, but knowledge of the salivary glands is lacking. In the digestive tract of insects, the carbonic anhydrase (CA) enzyme family is believed to contribute to the luminal pH gradient. Presence of CA in the digestive tract of A. domesticus has been reported, but not the cellular localisation. This study examined the digestive tract of A. domesticus, including salivary glands, and the cellular localisation and activity of CA in fed or starved (48 h) males and females. Tissues were collected from third-generation offspring of wild A. domesticus captured in Sweden and the histology of the salivary glands and the cellular localisation of CA in the digestive tract of A. domesticus were determined, to our knowledge for the first time. The salivary glands resembled those of grasshoppers and locusts, and we suggest the two main cell types present to be parietal and zymogenic cells. Histochemical analysis revealed that CA activity was localised in midgut epithelium, both main cell types of salivary gland, and muscle along the entire digestive tract. These findings support the suggestion that CA contributes to digestive tract luminal pH gradient, by driving acidic secretions from the salivary glands and alkaline secretions from the midgut. Starvation resulted in significantly reduced body size and weight, but neither starvation nor sex had any effect on CA activity or localisation.

scholarly journals H3K9 Promotes Under-Replication of Pericentromeric Heterochromatin in Drosophila Salivary Gland Polytene Chromosomes

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 93 ◽  
Author(s):  
Robin Armstrong ◽  
Taylor Penke ◽  
Samuel Chao ◽  
Gabrielle Gentile ◽  
Brian Strahl ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Dna Replication ◽  
Polytene Chromosomes ◽  
Cell Types ◽  
Gene Replacement ◽  
Pericentric Heterochromatin ◽  
Replication Initiation ◽  
H3k9 Methylation ◽  
Diploid Cells ◽  
And Function

Chromatin structure and its organization contributes to the proper regulation and timing of DNA replication. Yet, the precise mechanism by which chromatin contributes to DNA replication remains incompletely understood. This is particularly true for cell types that rely on polyploidization as a developmental strategy for growth and high biosynthetic capacity. During Drosophila larval development, cells of the salivary gland undergo endoreplication, repetitive rounds of DNA synthesis without intervening cell division, resulting in ploidy values of ~1350C. S phase of these endocycles displays a reproducible pattern of early and late replicating regions of the genome resulting from the activity of the same replication initiation factors that are used in diploid cells. However, unlike diploid cells, the latest replicating regions of polyploid salivary gland genomes, composed primarily of pericentric heterochromatic enriched in H3K9 methylation, are not replicated each endocycle, resulting in under-replicated domains with reduced ploidy. Here, we employ a histone gene replacement strategy in Drosophila to demonstrate that mutation of a histone residue important for heterochromatin organization and function (H3K9) but not mutation of a histone residue important for euchromatin function (H4K16), disrupts proper endoreplication in Drosophila salivary gland polyploid genomes thereby leading to DNA copy gain in pericentric heterochromatin. These findings reveal that H3K9 is necessary for normal levels of under-replication of pericentric heterochromatin and suggest that under-replication at pericentric heterochromatin is mediated through H3K9 methylation.

scholarly journals Physiological and morphological evidence for coupling in mouse salivary gland acinar cells.

1978 ◽  
Vol 79 (1) ◽  
pp. 20-26 ◽  
Author(s):  
S B Kater ◽  
N J Galvin
Keyword(s):  
Salivary Gland ◽  
Lucifer Yellow ◽  
Electrical Coupling ◽  
Freeze Fracture ◽  
Acinar Cells ◽  
Cell Types ◽  
Morphological Evidence ◽  
Secretory Cells ◽  
Intercellular Exchange ◽  
Dc Current

Three experimental techniques were employed to examine coupling between acinar cells of the mouse salivary gland. Passage of DC current pulses via intracellular microelectrodes between neighboring cells showed that small ions could be directly passed from one cell to another. Intracellular iontophoresis of the dye Lucifer Yellow CH into a single cell indicated that small molecules could spread by means of intercellular cytoplasmic bridges througout an acinus and, occasionally, into cells of adjacent acini. Freeze-fracture replicas of acinar cell membranes indicated the presence of gap junctions which were correlated with both electrical and dye coupling experiments. Suggestions are made for the function of direct intercellular exchange in salivary secretory cells. The role of electrical coupling in coordination of the activity of different secretory cell types is discussed as one possible function.

scholarly journals Mucoepidermoid Carcinoma of the Palatine Tonsil

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Lucas Novaes Teixeira ◽  
Victor Angelo Martins Montalli ◽  
Luiz Carlos Santana Teixeira ◽  
Fabrício Passador-Santos ◽  
Andresa Borges Soares ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Oral Cavity ◽  
Mucoepidermoid Carcinoma ◽  
Unusual Case ◽  
Cell Types ◽  
Palatine Tonsil ◽  
Soft Mass ◽  
Salivary Gland Malignancy ◽  
Adults And Children ◽  
Intermediate Cells

Mucoepidermoid carcinoma (MEC) is the most common primary salivary gland malignancy in both adults and children. It has a slight female predilection and usually presents as a painless, rubber-like or soft mass, which may be fixed or mobile. Histologically, MEC is comprised of a mixture of cell types including mucous, epidermoid, and intermediate cells that can be arranged in solid nests or cystic structures. In the oral cavity, it most frequently occurs at the palate or buccal mucosa. The present paper aimed to describe an unusual case of MEC arising in the palatine tonsil.

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