Dimorphic Cells Research Articles

Adipose stem cells are sexually dimorphic cells with dual roles as preadipocytes and resident fibroblasts

Cell identities are defined by intrinsic transcriptional networks and spatio-temporal environmental factors. Here, we explored multiple factors that contribute to the identity of adipose stem cells, including anatomic location, microvascular neighborhood, and sex. Our data suggest that adipose stem cells serve a dual role as adipocyte precursors and fibroblast-like cells that shape the adipose tissue’s extracellular matrix in an organotypic manner. We further find that adipose stem cells display sexual dimorphism regarding genes involved in estrogen signaling, homeobox transcription factor expression and the renin-angiotensin-aldosterone system. These differences could be attributed to sex hormone effects, developmental origin, or both. Finally, our data demonstrate that adipose stem cells are distinct from mural cells, and that the state of commitment to adipogenic differentiation is linked to their anatomic position in the microvascular niche. Our work supports the importance of sex and microvascular function in adipose tissue physiology.

Dimorphic cells: a common feature throughout the low nuclear grade breast neoplasia spectrum

Columnar cell lesions (CCLs) are recognized precursor lesions of the low nuclear grade breast neoplasia family. CCLs are cystic enlarged terminal duct lobular units with monotonous (monoclonal) columnar-type luminal cells. CCLs without atypia are regarded as benign and CCLs with atypia as true precursor lesions with clonal molecular changes, a certain progression risk, and an association with more advanced lesions. However, reproducibility of designating atypia in CCL is not optimal, and no objective markers of atypia have been identified, although 16q loss seems to be associated with atypical CCLs. Dimorphic (“pale”) cell populations have been described in low nuclear grade ductal carcinoma in situ (DCIS) but not in CCLs and atypical ductal hyperplasia (ADH). Therefore, we searched for pale cells in CCL (N = 60), ADH (N = 41), and DCIS grade 1 (N = 84). Diagnostic criteria were derived from the WHO, and atypia was designated according to the Schnitt criteria. Pale cells occurred in 0% (0/30), 73% (22/30), 56% (23/41), and 76% (64/84) of CCLs without atypia, CCLs with atypia, ADH, and DCIS grade 1, respectively. Pale cells expressed ERα, E-cadherin and p120 and variably cyclin D1, and lacked expression of CK5 and p63. In conclusion, dimorphic “pale” cells occur throughout the low nuclear grade progression spectrum, increasing in frequency with progression. Interestingly, CCL lesions without atypia do not seem to bear showed pale cells, indicating that the presence of pale cells may serve as a diagnostic morphological feature of atypia in CCLs.

Clinicopathological study of a dimorphic variant of breast carcinoma

BackgroundDimorphic cells have abundant clear cytoplasm similar to myoepithelial cells, and the nuclei are identical to those in adjacent malignant columnar epithelial cells. A dimorphic variant of a breast carcinoma involves a neoplastic proliferation of epithelial cells including dimorphic cells.MethodsThe subjects were patients with primary breast carcinoma, who underwent surgical resection at the Hospital of Dokkyo Medical University between 2000 and 2016, and were reviewed and diagnosed with a dimorphic variant of breast carcinoma.ResultsDimorphic ICs typically showed a low-grade tumor and Hormonal receptor (HR) (estrogen and/or progesterone)+/HER2− subtype. Age, mean tumor size, status of nodal metastasis, stage and disease-free survival and overall survival did not differ between dimorphic and non-dimorphic ICs. The dimorphic cells were negative for p63 and cytokeratin 5/6 and 14 in most cases. In contrast, dimorphic cells were positive for HR, androgen receptor, and showed marked membrane-associated staining for E-cadherin and cytoplasmic staining for gross cystic disease fluid protein 15.ConclusionsThe morphological features of dimorphic cells may be confused with cells of other origins if the features of the dimorphic cells are not recognized. However, the typical morphological architecture of this carcinoma and expression of immunohistochemical markers support the diagnosis.

Dimorphic variant of ductal carcinoma in situ of the breast

We report a case of dimorphic variant of ductal carcinoma in situ (dimorphic DCIS), composed of an epithelium intermixed with columnar cells and dimorphic cells. The findings of typical DCIS architecture support categorization as DCIS on a low-power view. Furthermore, there was no difference in the nuclear morphology of the two cell types on the high-power view. The two cell types comprising dimorphic DCIS were negative for p63, CK 5/6 and 14. On the contrary, both cell types were diffusely positive for nuclear ER and AR, as well as marked membrane-associated staining for E-cadherin and cytoplasmic staining for GCDFP-15. These immunohistochemical marker results are similar to conventional DCIS and there were no differences in expression patterns between the columnar epithelial cells and dimorphic cells. The morphological features of dimorphic cells may be confused with cells of other origins if the features of dimorphic DCIS are not recognized. Careful observation of morphological architecture and expression of immunohistochemical markers may support diagnosis.

Co-occurrence of Dinophysis tripos and pectenotoxins in Argentinean shelf waters

The species Dinophysis tripos is a widely distributed marine dinoflagellate associated with diarrheic shellfish poisoning (DSP) events, which has been recently identified as a pectenotoxin (PTX) producer. In two sampling expeditions carried out during austral autumns 2012 and 2013 along the Argentine Sea (≈38–56°S), lipophilic phycotoxins were measured by tandem mass spectrometry coupled to liquid chromatography (LC–MS/MS) in size-fractionated plankton samples together with microscopic analyses of potentially toxic phytoplankton. PTX-2, PTX-11 and PTX-2sa were recurrently detected in the 50–200μm fractions, in association to D. tripos. PTX-2 was also widely distributed among the 20–50μm fractions, mostly related to Dinophysis acuminata. Okadaic acid or its analogs were not detected in any sample. This is the first report of D. tripos related to PTX in the Argentine Sea and the first record of PTX-11 and PTX-2sa for this area. The morphological variability of D. tripos, including the presence of intermediate, small and dimorphic cells, is described. Also, the micro- and mesoplanktonic potential grazers of Dinophysis spp. were explored.

Sexual Differentiation of the Nervous System: Where the Action Is

Sexual Differentiation of the Nervous System: Where the Action Is

A new species of Zygodon (Orthotrichaceae) from southern South America

Zygodon chilensis, a new species from Chile, is described and illustrated. The new species is mainly distinguished by its long seta, twisted to the right in the lower part and twisted to the left in the upper regions. It possesses lanceolate leaves with dimorphic basal leaf cells, and has abundant coloured propagules which are sometimes branched. The characteristic propagules displayed by Zygodon chilensis are unique within the genus. This species grows as an epiphyte on both deciduous trees and conifers in forest areas of southern Chile.

Genome-wide analysis of sex-enriched gene expression during C. elegans larval development

Sex determination in C. elegans is controlled by the TRA-1 zinc finger protein, a Ci/GLI homolog that promotes female cell fates throughout the body. The regulatory hierarchy that controls TRA-1 is well established, but the downstream effectors that establish sexual dimorphism during larval development remain largely unknown. Here, we describe the use of cDNA microarrays to identify sex-enriched transcripts expressed during three stages of C. elegans larval development. By excluding previously identified germline-enriched transcripts, we focused on somatic sexual development. This approach identified a large number of sex-enriched transcripts that are good candidates to encode regulators of somatic sexual development. We found little overlap between genes with sex-enriched expression in early versus late larval development, indicating that distinct sexual regulatory programs operate at these times. Genes with sex-enriched expression are found throughout the genome, with no strong bias between autosomes and X chromosomes. Reporter gene analysis revealed that these genes are expressed in highly specific patterns in a variety of sexually dimorphic cells. We searched for TRA-1 consensus DNA binding sites near genes with sex-enriched expression, and found that most strongly sex-enriched mRNAs are likely to be regulated indirectly by TRA-1. These results suggest that TRA-1 controls sexual dimorphism through a small number of intermediary regulators rather than by acting directly on the full constellation of genes involved in sex-specific differentiation.

SMALL CELL AND INTERMEDIATE CELL FORMATION IN SPECIES OF DINOPHYSIS (DINOPHYCEAE, DINOPHYSIALES)

Observations of two distinct size classes with similar shape in natural populations of Dinophysis Ehrenberg were first reported by Jorgensen in 1923 and intermediate forms exhibiting a continuum between the typical vegetative cell and a putative small cell by Wood in 1954. Focused attention on Dinophysis spp. associated with diarrhetic shellfish intoxications in the last decade has provided new examples of small cells in the genus, sometimes with contours dissimilar from the corresponding vegetative cells; dimorphic individuals; and large/small cell couplets. This work was based on in situ observations during intensive sampling for cell cycle studies of Dinophysis acuminata Claparéde et Lachmann, Dinophysis acuta Ehrenberg, Dinophysis caudata Saville‐Kent, and Dinophysis tripos Gourret; on laboratory incubations of D. acuminata; and on a thorough search of documented information on morphological variability of Dinophysis spp. During in situ division, most dividing cells exhibit a normal longitudinal fission, but some (1%–10%) undergo a “depauperating” fission, leading to pairs of dimorphic cells with dissimilar moieties. After separation and sulcal list regeneration, these dimorphic cells become D. skagii Paulsen, D. dens Pavillard, D. diegensis Kofoid, and D. diegensis Kofoid var. curvata‐like individuals, which can also be observed forming couplets D. acuminata/D. skagii, D. acuta/D. dens, and D. caudata/D. diegensis attached by their ventral margins. Small cells can grow again to large size, as shown in laboratory incubations of D. acuminata, thus partly explaining observations of thecal intercalary bands, and intermediate forms. The sexual nature of the small cells will not be unequivocally demonstrated until controlled germination of the alleged cyst forms is achieved, and some intermediate forms may correspond to undescribed stages after cyst germination. These observations suggest common patterns in the life cycle of Dinophysis spp. Intraspecific morphological variability of Dinophysis spp. in a given geographic area can largely be attributed to small cell formation, as a response to changing environmental conditions, and may be a part of the sexual cycle of these species. Small cells seem to be able to enlarge, leading to intermediate cell and further vegetative cell formation as part of a three‐looped life history pattern in Dinophysis.

The ultrastructure of the dimorphic infection cells of <i>Haptoglossa heteromorpha </i>illustrates the developmental plasticity of infection apparatus structures in a nematode parasite

The ultrastructure of the dimorphic infection cells of <i>Haptoglossa heteromorpha </i>illustrates the developmental plasticity of infection apparatus structures in a nematode parasite

Changes in mitochondrial structure of dimorphic cells of Endomycopsis fibuligera in saline medium.

Since we first developed in 1964 to investigate electronmicroscopically the fine structure of an yeast,Endomycopsis fibuligera which behaves to grow in dimorphic type of the cell, namely yeast-like and filamentous ones, many papers concerned with the representations of the cell structure in comparison between two types of the cell. The purpose of the present investigation, therefore, is to clarify the significance of the effect of NaCl-hypertonicity on the structural changes in the grown cells in each type and the intracellular localization of NaCl taken up by the cells. An unique feature of grown cells in NaCl medium under shaking condition was a reminiscence of membrane system, resulted from the progressive degradation of mitochondria in growing cells. The difference of pronounced changes in mitochondrial degradation between yeast-like and filamentous cells indicated that the shape and the structure were differently linked to the cell metabolism in each type. This evidence has been approached by considering the comparative biogenesis of the irregular outline of vacuole in shape and the intravacuolar localization of NaCl taken up by the cell. The mitochondria can be identified both as a specific structural and a specific biochemical system, and current investigations aim at a more detailed understanding of the relationship between metabolic activity and structure. Halophytes and halophilic microorganisms must grow with high energy efficiency supplied by mitochondrial function to overcome the severe saline environment (Yabe et al. 1965, 1966). Conversely, although it has been obvious that slight but significant departures from a linear growth response of a non-halophilic yeast such asEndomycopsis fibuligera (formerly nomenclatured asE. fibuliger), under saline condition, must be taken into account of a specific ion effect in addition to the osmotic effect as so called dual effect, it will be expected that the progressive increase in cellular osmotic pressure with increasing salt concentration of external medium was directly and primarily related to the formation and the function of the mitochondria during decreased growth by added salt (Takada andKasakawa 1966 a, b). On the other hand, we have previously reported that when the cells ofEndomycopsis fibuligera were grown anaerobically, we could not found any mitochondrial structure within the cell and found concentrically arranged membrane system by means of electron microscopy (Hiraoka et al. 1966 b). There has been another experimental basis for believing that added NaCl or LiCl to hypertonic medium might to disintegrate the mitochondrial structure during growth, because this condition induced to enhance the anaerobic respiration associated with the depressed aerobic respiration accompanied with modified and different cytochrome pattern. A correlated ultrastructural study of mitochondrial structural states inEndomycopsis fibuligera has provided direct evidence of the effect of saline condition on mitochondrial morphologyin vivo.