Ultrastructure of myoid cells in the chick thymus

Chan, AS

doi:10.1080/00071669508417768

Cited by 5 publications

(3 citation statements)

References 18 publications

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“…Thymic anatomical microenvironments are unique and molecular gradients control T-cell development [112]. Eutherian myoid cells localize in the thymic medulla, although occasional expression in the corticomedullary junction has been observed [113,114]. Although we have sequenced equivalent amounts of cDNA from both thymuses, it is possible that more thymic epithelial cells and thymocytes were harvested in the thoracic thymus, whilst a greater number of myoid cells were sampled in the cervical.…”

Section: Resultsmentioning

confidence: 99%

Transcriptomic analysis supports similar functional roles for the two thymuses of the tammar wallaby

et al. 2011

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BackgroundThe thymus plays a critical role in the development and maturation of T-cells. Humans have a single thoracic thymus and presence of a second thymus is considered an anomaly. However, many vertebrates have multiple thymuses. The tammar wallaby has two thymuses: a thoracic thymus (typically found in all mammals) and a dominant cervical thymus. Researchers have known about the presence of the two wallaby thymuses since the 1800s, but no genome-wide research has been carried out into possible functional differences between the two thymic tissues. Here, we used pyrosequencing to compare the transcriptomes of a cervical and thoracic thymus from a single 178 day old tammar wallaby.ResultsWe show that both the tammar thoracic and the cervical thymuses displayed gene expression profiles consistent with roles in T-cell development. Both thymuses expressed genes that mediate distinct phases of T-cells differentiation, including the initial commitment of blood stem cells to the T-lineage, the generation of T-cell receptor diversity and development of thymic epithelial cells. Crucial immune genes, such as chemokines were also present. Comparable patterns of expression of non-coding RNAs were seen. 67 genes differentially expressed between the two thymuses were detected, and the possible significance of these results are discussed.ConclusionThis is the first study comparing the transcriptomes of two thymuses from a single individual. Our finding supports that both thymuses are functionally equivalent and drive T-cell development. These results are an important first step in the understanding of the genetic processes that govern marsupial immunity, and also allow us to begin to trace the evolution of the mammalian immune system.

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Section: Resultsmentioning

confidence: 99%

Transcriptomic analysis supports similar functional roles for the two thymuses of the tammar wallaby

et al. 2011

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“…The authors did not find references to mononuclear cells with well‐defined sarcomeres in the gills of any species of teleost. Nonetheless, several researchers (Chan, 1992; Curtis et al ., 1979; Jablonska‐Mestanova et al ., 2013; Raviola & Raviola, 1967) have observed and described cells with similar characteristics, called myoid cells, in the thymic medulla of mammals, birds, reptiles and amphibians. In the studies carried out on the thymus of Neoceratodus forsteri (Krefft, 1870) (Dipnoi, Ceratodontiformes) and Oreochromis niloticus (Linneo, 1758) (Perciformes, Cichlidae), Mohammad et al .…”

Section: Discussionmentioning

confidence: 99%

Gill morphology and morphometry of the facultative air‐breathing armoured catfish, Corydoras paleatus, in relation on aquatic respiration

Plaul

Díaz

Barbeito

2021

Journal of Fish Biology

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The Neotropical armoured catfish Corydoras paleatus is a facultative air‐breathing teleost commonly exported as ornamental fish. In this species, air breathing enables it to survive and inhabit freshwater environments with low oxygen levels. Therefore, it is important to analyse the gills from a morphological aspect and its dimensions in relation to body mass with reference to aquatic respiration. For that, the gills were analysed using a stereoscopic microscope for morphometric studies, and structural and ultrastructural studies were carried out to compare the four branchial arches. Furthermore, two immunohistochemical techniques were used to locate and identify the presence of a Na+/K+ pump. The characterization of the potential for cell proliferation of this organ was assessed using an anti‐PCNA antibody. The results show that gills of C. paleatus present some characteristics related to its diet and lifestyle, such as the limited development of gill rakers and the abundance of taste buds. In addition, other special features associated with the environment and bimodal breathing were observed: scarce and absent mucous cells (MCs) in the gill filaments and branchial lamellae, respectively, and the localization of mitochondria‐rich cells (MRCs) covering the basal third of the branchial lamellae, which reduces the gill respiratory area. A peculiar finding in the gill epithelium of this armoured catfish was the presence of mononuclear cells with sarcomeres similar to myoid cells, whose functional importance should be determined in future studies. Finally, in C. paleatus, the interlamellar space of gill filaments is an important site for cell turnover and ionoregulation; the latter function is also performed by the branchial lamellae.

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“…Another cell type is the myoid cell, which occurs in small numbers in humans and mice but is quite common in reptilian and avian species. 1,10,23,27 Myoid cells are often isolated to the medulla. It is believed that they have an embryological origin from the neural crest and hence are S-100 positive.…”

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confidence: 99%

A Rhabdomyoma Within a Multilocular Thymic Cyst in a p53-Null Mouse

et al. 2010

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A 9-month-old p53-null female mouse was found dead in its cage. At necropsy, a large thymic mass encompassed the heart. Microscopically, the mass was composed of numerous varying-sized cysts lined with simple squamous epithelial cells to columnar ciliated cells. Also present within this mass was a large aggregate of loosely arranged fusiform-shaped cells. These cells also were found in smaller numbers in the connective tissue surrounding the cysts. The larger aggregate of fusiform cells was positive for desmin and S-100 and negative for smooth muscle actin. Electron microscopy revealed well-formed Z lines and I bands of skeletal muscle phenotype. A diagnosis of rhabdomyoma within a congenital multilocular thymic cyst was made. The thymus contains a small population of myoid cells, which should be taken in consideration when evaluating thymic tumors.

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Ultrastructure of myoid cells in the chick thymus

Cited by 5 publications

References 18 publications

Transcriptomic analysis supports similar functional roles for the two thymuses of the tammar wallaby

Transcriptomic analysis supports similar functional roles for the two thymuses of the tammar wallaby

Gill morphology and morphometry of the facultative air‐breathing armoured catfish, Corydoras paleatus, in relation on aquatic respiration

A Rhabdomyoma Within a Multilocular Thymic Cyst in a p53-Null Mouse

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