Abundant Rough Endoplasmic Reticulum Research Articles

Intracellular organelles remodeling in myocardial endotheliocytes in COVID-19: an autopsy-based study

ABSTRACT It is known that the unfavorable outcome in patients infected with SARS-CoV-2 may be associated with the development of complications caused by heart damage due to the direct virus action. The mechanism of these cardiovascular injuries caused by SARS-CoV-2 infection has not been fully understood; however, the study of COVID-19-associated myocardial microcirculatory dysfunction can represent the useful strategy to solving this challenge. Thus, here we aimed to study the ultrastructural organization of endothelial cells of myocardial capillaries in patients with COVID-19. The morphology of endotheliocytes of the myocardial blood capillaries in patients with COVID-19 was studied on cardiac autopsy material using transmission electron microscopy. The endotheliocytes of myocardial capillaries in patients with COVID-19 were characterized by the abundant rough endoplasmic reticulum (ER) membranes, the Golgi complex, and free polysomal complexes of ribosomes and lipids. The presence of double membrane vesicles with virions and zippered ER was detected in the cytoplasm of endotheliocytes. The revealed endothelial ultrastructural changes indicate the remodeling of intracellular membranes during SARS-CoV-2 infection. Our findings confirm the formation of virus-induced structures in myocardial endothelial cells considered critical for viral replication and assembly. The data may elucidate the mechanisms of endothelial dysfunction development in patients with COVID-19 to provide potential targets for drug therapy.

Differential osteoblastic activity in primary metaphyseal trabecular and secondary trabeculae of c-fos deficient mice

ObjectivesIt has been highlighted that osteoblastic activities in remodeling-based bone formation are coupled with osteoclastic bone resorption while those in modeling-based bone formation are independent of osteoclasts. This study aimed to verify whether modeling-based bone formation can occur in the absence of osteoclasts. MethodsWe performed histochemical analyses on the bone of eight-week-old male wild-type and c-fos−/− mice. Histochemical analyses were conducted on primary trabeculae near the chondro-osseous junction (COJ), sites of modeling-based bone formation, and secondary trabeculae, sites of remodeling-based bone formation, in the femora and tibiae of mice. ResultsAlkaline phosphatase (ALP) immunoreactivity, a marker of osteoblastic lineages, was observed in the metaphyseal trabeculae of wild-type mice, while ALP was scattered throughout the femora of c-fos−/− mice. PHOSPHO1, an enzyme involved in matrix vesicle-mediated mineralization, was predominantly detected in primary trabeculae and also within short lines of osteoblasts in secondary trabeculae of wild-type mice. In contrast, femora of c-fos−/− mice showed several patches of PHOSPHO1 positivity in the primary trabeculae, but there were hardly any patches of PHOSPHO1 in secondary trabeculae. Calcein labeling was consistently observed in primary trabeculae close to the COJ in both wild-type and c-fos−/− mice; however, calcein labeling in the secondary trabeculae was only detected in wild-type mice. Transmission electron microscopic examination demonstrated abundant rough endoplasmic reticulum in the osteoblasts in secondary trabeculae of wild-type mice, but not in those of c-fos−/− mice. ConclusionsOsteoblastic activities at the sites of modeling-based bone formation may be maintained in the absence of osteoclasts.

Light and Electron Microscopy of Buccal Salivary Glands of the Dromedary Camel

The study was aimed to investigate the light and electron microscopic structure of buccal salivary glands in the dromedary (Camelus dromedarius). Anatomically, the dromedary camel buccal glands were well-developed and were located on the lateral side of the cheek. Three parts (groups) of the buccal glands could be observed: dorsal, middle and ventral parts. Histologically, the secretory units were tubule-acinar, surrounded by myo-epithelial cells and supported by connective tissue. Whereas, the dorsal glands were purely mucous and the ventral glands were purely serous in secretion, the middle ones were muco-serous with predominant mucous cells. Ultra-structurally, the glandular cells of the serous secretory units (type I cells) contained numerous microvilli, many electron-dense secretory granules, abundant rough endoplasmic reticulum and mitochondria. On the other hand, the mucous-secreting cells (type II cells) appeared with numerous electron-translucent supra-nuclear granules and flat basal nuclei; dilated tubules of rough endoplasmic reticulum; fewer mitochondria and Golgi bodies were also observed. The obtained results have been compared with the previous reports on salivary glands of camel and other mammalian species.

Ultrastructure and histochemistry of the subepithelial glands of the nasal septal island in dromedaries with special reference to the possible functions.

The nasal septal island (NSI) is a sensory patch of neuroepithelium located within the soft tissue of the nasal septum in dromedaries. The island has unique anatomical features, including the specialized subepithelial glands. The aim of the present study was to describe the microscopic features and ultrastructure of these subepithelial glands and to speculate the possible functions. A total of 10 camel heads were used for the study. Unlike the serous and mucous airway glands, the NSI glands' ultrastructural features were typical for cells of the (Amine Precursor Uptake and Decarboxylation, APUD) system. These features were included, membrane bound secretory vesicles of varying electron density, smooth endoplasmic reticulum in the form of vesicles; electron dense mitochondria, abundant rough endoplasmic reticulum and free ribosomes. Alcian-PAS identifiable mucus granules were not observed, except for few clusters of cells, located at the luminal surface. The probable functions were discussed on basis of cellular morphology and context. In a conclusion, the NSI subepithelial glands in dromedaries had unique anatomical structures, and as many other APUD cells, they had the machinery required for synthesis of a variable number of biologically active peptides, amines and chemical mediators.

Dedifferentiation of smooth muscle cells in intracranial aneurysms and its potential contribution to the pathogenesis

Smooth muscle cells (SMCs) are the major type of cells constituting arterial walls and play a role to maintain stiffness via producing extracellular matrix. Here, the loss and degenerative changes of SMCs become the major histopathological features of an intracranial aneurysm (IA), a major cause of subarachnoid hemorrhage. Considering the important role of SMCs and the loss of this type of cells in IA lesions, we in the present study subjected rats to IA models and examined how SMCs behave during disease progression. We found that, at the neck portion of IAs, SMCs accumulated underneath the internal elastic lamina according to disease progression and formed the intimal hyperplasia. As these SMCs were positive for a dedifferentiation marker, myosin heavy chain 10, and contained abundant mitochondria and rough endoplasmic reticulum, SMCs at the intimal hyperplasia were dedifferentiated and activated. Furthermore, dedifferentiated SMCs expressed some pro-inflammatory factors, suggesting the role in the formation of inflammatory microenvironment to promote the disease. Intriguingly, some SMCs at the intimal hyperplasia were positive for CD68 and contained lipid depositions, indicating similarity with atherosclerosis. We next examined a potential factor mediating dedifferentiation and recruitment of SMCs. Platelet derived growth factor (PDGF)-BB was expressed in endothelial cells at the neck portion of lesions where high wall shear stress (WSS) was loaded. PDGF-BB facilitated migration of SMCs across matrigel-coated pores in a transwell system, promoted dedifferentiation of SMCs and induced expression of pro-inflammatory genes in these cells in vitro. Because, in a stenosis model of rats, PDGF-BB expression was expressed in endothelial cells loaded in high WSS regions, and SMCs present nearby were dedifferentiated, hence a correlation existed between high WSS, PDGFB and dedifferentiation in vivo. In conclusion, dedifferentiated SMCs presumably by PDGF-BB produced from high WSS-loaded endothelial cells accumulate in the intimal hyperplasia to form inflammatory microenvironment leading to the progression of the disease.

\u201cProstate telocytes change their phenotype in response to castration or testosterone replacement\u201d

Telocytes are CD34-positive cells with a fusiform cell body and long, thin cytoplasmic projections called telopodes. These cells were detected in the stroma of various organs, including the prostate. The prostate is a complex gland capable of undergoing involution due to low testosterone levels; and this condition can be reversed with testosterone replacement. Telocyte function in the mature prostate remains to be dermined, and it is not known whether telocytes can take place in tissue remodeling during prostate involution and regrowth. The present study employed structural, ultrastructural and immunohistochemical methods to investigate the telocyte’s phenotypes in the ventral prostate (VP) from control (CT), castrated (CS) and testosterone replacement (TR) groups of adult male Wistar rats. Telocytes were found in the subepithelial, perimuscular and interstitical regions around glandular acini. Telocytes from CT animals have condensed chromatin and long and thin telopodes. In CS group, telocytes appeared quiescent and exhibited layers of folded up telopodes. After TR, telocytes presented loose chromatin, abundant rough endoplasmic reticulum and enlarged telopodes, closely associated with bundles of collagen fibrils. We called these cells “telocytes with a synthetic phenotype”. As testosterone levels and glandular morphology returned toward to the CT group parameters, after 10 days of TR, these telocytes progressively switched to the normal phenotype. Our results demonstrate that telocytes exhibit phenotypic plasticity upon androgen manipulation and interact with fibroblast and smooth muscle cells to maintain glandular architecture in control animals and during tissue remodeling after hormonal manipulation.

The androgenic gland in male morphotypes of the Amazon River prawn Macrobrachium amazonicum (Heller, 1862)

Sexual differentiation and primary and secondary sexual characteristics in male crustaceans are modulated by hormones produced in the androgenic gland (AG). The AG is also responsible for the determination of morphotypes in caridean shrimps, such as Macrobrachium amazonicum that shows four morphotypes: translucent claw (TC), cinnamon claw (CC), green claw 1 (GC1) and green claw 2 (GC2). Here, we verified the anatomical, histological and ultrastructural characteristics of the AG in different morphotypes of this species with both amphidromous and hololimnetic life cycles. In submissive morphotypes (TC and CC), the AGs are reduced and concentrated in the terminal expansion of the distal portion of vasa deferentia (DVD), the ejaculatory ducts (ED). In dominant morphotypes (GC1 and GC2) these glands lie along the DVD and ED. Two morphological stages (I and II) were recorded for AG cells. In submissive morphotypes stage I cells predominated in the AGs, while in dominant morphotypes stage II cells were more common. AG cells in both stages were positive for proteins, confirming the protein nature of the secreted hormone. Stage I cells have abundant rough endoplasmic reticulum (RER) with numerous parallel cisternae, whereas in stage II cells, the cisternae of RER are highly dilated. Stage II cells do not produce secretory granules, but they undergo hypertrophy and the hormone release to hemolymph probably occurs by holocrine secretion. The AGs in TC, GC1 and GC2 morphotypes increase as the animals grow and are larger in GC1 males. On the other hand, AGs decrease in the CC morphotype as the animal grows. These differences are related to the type of reproductive strategy adopted by each morphotype. In M. amazonicum, the AGs show the same morphological, histochemical and ultrastructural patterns between the different life history populations.

Micromorphology and histochemistry of the secretory apparatus of Plumbago auriculata Lam.

This study interprets the structure and provides insights on the phyto-compounds of the leaves and calyces of Plumbago auriculata and evaluates its potential as a medicinal plant based on the presence of these compounds. Structure and possession of phyto-compounds were determined using light and electron microscopy and various histochemical tests. Glandular capitate and non-glandular uniserate trichomes were present on the surface of the calyx. Glandular trichomes bear a close resemblance to the digestive glands of the genus Drosera. Salt glands present on the leaf surface were abundant on the abaxial surface and revealed the presence of “transfer cells” reported for the first time in the genus. Abundant mitochondria, mini vacuoles, ribosomes, dictyosomes and rough endoplasmic reticulum cisternae were actively involved in the secretory process. Histochemical staining also revealed the presence of alkaloids and phenolic compounds that are of medicinal importance used to treat multiple ailments and also function as chemical deterrents in plants. Overall, this study contributes to the existing body of knowledge on the secretory structures of P. auriculata and provides new insights on the ultrastructural and histochemical aspects of the species.

Bioprinting of glioma stem cells improves their endotheliogenic potential.

Glioblastoma (GBM), with rich blood vessels and high invasiveness, is the most common malignant primary brain tumor. The current treatment strategies are less effective, resulting in tumor recurrence. Tumor angiogenesis plays an important role in the occurrence, development and metastasis of GBM. Currently, GBM has been treated by inhibiting tumor angiogenesis. In-depth study of tumor angiogenesis is of great significance for the treatment of GBM. Recent studies have shown that glioma stem cells (GSCs) are involved in tumor vascularization by secreting vascular endothelial growth factor (VEGF). It is necessary to construct an ideal in vitro model to study the mechanism of GSCs in tumor vascularization. Here we used extrusion-based three-dimensional (3D) bioprinting technology to fabricate GSCs tumor model. In this study, the viability of cells after bioprinting was 86.27 ± 2.41%. Furthermore, compared with traditional suspension culture, the proliferation of 3D printed GSCs was more stable. Through the transmission electron microscopy (TEM), numerous long microvilli of cells cultured in 3D bioprinted scaffolds were observed. 3D bioprinted GSCs also have more abundant mitochondria and rough endoplasmic reticulum. Additionally, the stemness properties, the expression of tumor angiogenesis-related genes and vascularization potential of 3D bioprinted GSCs in vitro were higher than that of suspension cultured cells. In summary, 3D bioprinted cell-laden hydrogel scaffolds provide a proper model for investigating the biological characteristics of GSCs and tumor angiogenesis.

Ultrastructure and immunohistochemical characterization of proteins concerned with the secretory machinery in goat ceruminous glands.

The expression of soluble N-ethylmaleimide sensitive fusion attachment protein receptor (SNARE) proteins in apocrine glands has not been fully elucidated. In addition to performing ultrastructural observation of the ceruminous glands in goats, our study focuses on the demonstration of β-defensins, SNARE proteins and Rab3D in these glands with the use of immunohistochemical methods. The secretory cells were equipped with two types of vesicles, Golgi apparatus and abundant rough endoplasmic reticulum (ER). Additionally, in some of them, the characteristic concentric structures composed of rough ER were observed in their circum- and infranuclear parts. The expression of phosphorylated inositol requiring enzyme 1rrwas also detected. These findings may indicate their ability to produce numerous secretory proteins and the maintenance of homeostasis in the glandular cells. Furthermore, β-defensins were demonstrated as products of the ceruminous glands. The present investigation also revealed the presence of SNARE proteins and Rab3D. It is suggested that these proteins are concerned with the secretory machinery of this gland type.

Detailed analysis of a superficial CD34-positive fibroblastic tumor: A case report and review of the literature.

Superficial cluster of differentiation (CD)34-positive fibroblastic tumor (SCPFT) is a rare mesenchymal neoplasm of borderline malignancy. It is characterized by a superficial location, marked cellular pleomorphism, an extremely low incidence of mitotic figures, and strong CD34 immunohistochemical positivity. As SCPFT is a recently described neoplasm, its characteristics are yet to be fully elucidated. To the best of our knowledge, no detailed studies regarding the imaging findings and cytogenetic analyses of SCPFTs exist. The present study describes a typical case of an 18-year-old man who developed an SCPFT measuring 87×70×80 mm in the subcutaneous adipose tissue of his right thigh. Computed tomography (CT) revealed a well-marginated tumor without calcification, and the enhancement on CT was weak. The tumor demonstrated abnormal uptake on 2-(18F) fluoro-2-deoxy-D-glucose positron emission tomography (PET), with a maximum standardized uptake value of 2.57. Magnetic resonance imaging (MRI) revealed a clearly defined tumor that exhibited homogeneous low signal intensity on T1-weighted imaging and high signal intensity on T2-weighted imaging, with small lobulated structures. Histopathologically, the tumor was composed of irregular spindle-to-oval-shaped cells with eosinophilic glassy cytoplasm and hyperchromatic, bizarre and pleomorphic nuclei that frequently exhibited intranuclear pseudoinclusions. Immunohistochemically, the tumor cells were diffusely and strongly positive for CD34. The Mindbomb E3 ubiquitin protein ligase 1 labeling index was 8.6%. Ultrastructurally, the tumor cells exhibited irregular or convoluted nuclei with abundant euchromatin-prominent nucleoli. The cytoplasmic organelles consisted of scattered, abundant rough endoplasmic reticulum, mitochondria, lysosomes, ribosomal rosettes and aggregated lipid globules. Of 18 metaphase cells identified, 2 demonstrated translocation between chromosomes 2 and 5 in cytogenetic studies. To the best of our knowledge, this is the first study describing imaging data (CT, MRI and PET-CT) and chromosomal aberrations for SCPFT.

Protective effect and related mechanism of tanshinol borneol ester on homocysteine induced rat bone marrow mesenchymal stem cells damage

Objective: To investigate the protective effect and potential mechanism of tanshinol borneol ester (TBE) on homocysteine(Hcy) induced rat bone marrow mesenchymal stem cells (BMSCs) damage. Methods: BMSCs were isolated and cultured in vitro by density gradient centrifugation and adherent culture method. BMSCs were divided into the control (normal isolation and culture), TBE-1(10 μmol/L TBE-1 solution with 100 μl), TBE-2 (10 μmol/L TBE-2 solution with 100 μl), Hcy (0.5 mmol/L Hcy solution with 100 μl), Hcy + TBE-1(0.5 mmol/L Hcy solution with 100 μl, and 10 μmol/L TBE-1 solution with 100 μl), Hcy + TBE-2 (0.5 mmol/L Hcy solution with 100 μl, and 10 μmol/L TBE-2 solution with 100 μl), Hcy+ TBE-1+ inhibitor group(0.5 mmol/L Hcy solution with 100 μl, 10 μmol/L TBE-1 solution with 100 μl, and 25 μmol/L LY294002(specific blocker of phosphatidylinositol 3 kinase) solution with 100 μl), Hcy+ TBE-2+ inhibitor group(0.5 mmol/L Hcy solution with 100 μl, 10 μmol/L TBE-2 solution with 100 μl, and 25 μmol/L LY294002 solution with 100 μl). Cell proliferation activity was detected by MTT assay. The T-SOD activity and malonaldehyde level of cells were measured by anthineoxidase method and TBA method, respectively, to evaluate cell oxidative and antioxidative activities. The ultrastructure of cells was observed under transmission electron microscope. The expression level of PKB and NF-κB of cells in various groups were detected with the immunocytochemical method. Results: (1)Cell proliferation activity in TBE-1 group and TBE-2 group was significantly increased compared with the control group (both P<0.01), and was similar between TBE-1 group and TBE-2 groups after 1, 12, 24 and 48 hours treatment.(2)The T-SOD activity in TBE-1 group and TBE-2 group was significantly higher than in control group (both P<0.01), while it was significantly lower in Hcy group, Hcy+ TBE-1 group, and Hcy+ TBE-2 group than in control group(all P<0.01), and was similar between control group, Hcy+ TBE-1+ inhibitor group, and Hcy+ TBE-2+ inhibitor group(all P>0.05). The T-SOD activity was higher in Hcy+ TBE-1 group and Hcy+ TBE-2 group than in Hcy group(both P<0.01), and was higher in Hcy+ TBE-1+ inhibitor group than in Hcy+ TBE-1 group(P<0.05) and was higher in Hcy+ TBE-2+ inhibitor group than in Hcy+ TBE-2 group(P<0.05). The malonaldehyde level was lower in TBE-1 group and TBE-2 group than in control group(both P<0.01), was higher in Hcy group, Hcy+ TBE-1 group, Hcy+ TBE-2 group, Hcy+ TBE-1+ inhibitor group, and Hcy+ TBE-2+ inhibitor group than in control group(all P<0.01), was lower in Hcy+ TBE-1 group and Hcy+ TBE-2 group than in Hcy group(both P<0.01), was higher in Hcy+ TBE-1+ inhibitor group than in Hcy+ TBE-1 group(P<0.05), was higher in Hcy+ TBE-2+ inhibitor group than in Hcy+ TBE-2 group(P<0.05). (3)Under electron microscope, BMSCs showed profound swelling, senescence and apoptosis of cells increased significantly in Hcy group, Hcy+ TBE-1+ inhibitor group, and Hcy+ TBE-2+ inhibitor group when compared with control group. BMSCs in the TBE-1 and TBE-2 groups presented with abundant rough endoplasmic reticulum, and very active cell metabolism signs. Compared with Hcy group, BMSCs edema, the number of aging and apoptotic cells, and cell injury severity were significantly less in TBE-1+ Hcy group and TBE-2+ Hcy. (4)The PKB level was higher in TBE-1 group and TBE-2 group than in control group(both P<0.01), was lower in Hcy group, Hcy+ TBE-2 group, Hcy+ TBE-1+ inhibitor group, and Hcy+ TBE-2+ inhibitor group than in control group(all P<0.01), was similar between control group and Hcy+ TBE-1 group(P>0.05), was higher in Hcy+ TBE-1 group and Hcy+ TBE-2 group than in Hcy group(both P<0.05), was lower in Hcy+ TBE-1+ inhibitor group than in Hcy+ TBE-1 group(P<0.05), and was lower in Hcy+ TBE-2+ inhibitor group than in Hcy+ TBE-2 group(P<0.05). The NF-κB level was higher in TBE-1 group and TBE-2 group than in control group(both P<0.01), was lower in Hcy group, Hcy+ TBE-1 group, Hcy+ TBE-2 group, Hcy+ TBE-1+ inhibitor group, and Hcy+ TBE-2+ inhibitor group than in control group(P<0.01 or 0.05), was higher in Hcy+ TBE-1 group and Hcy+ TBE-2 group than in Hcy group(both P<0.05), was lower in Hcy+ TBE-1+ inhibitor group than in Hcy+ TBE-1 group(P<0.05) and was lower in Hcy+ TBE-2+ inhibitor group than in Hcy+ TBE-2 group(P<0.05). Conclusion: Tanshinol borneol ester can promote the proliferation of BMSC, and attenuate the homocysteine induced rat BMSCs damage possibly through activation of phosphatidylinositol 3 kinase/PKB signal transduction and its downstream signal pathway protein NF-κB.

The epithelial cytotypes of hepatopancreas in the Chinese mitten crab Eriocheir sinensis (Decapoda, Varunidae)

The Chinese mitten crab, Eriocheir sinensis, is an economically important crustacean. However, the hepatopancreas structure of the crab has not been fully disclosed. Here, we employed light microscopy and transmission electron microscopy to identify the epithelial cytotypes of the hepatopancreas. The hepatopancreas consisted of four epithelial cytotypes, which were B (blister-like), R (resorptive), F (fibrillar), and E (embryonic) cells. B cells had club-shaped nuclei, scant cytoplasm, and contained some small vacuoles and one extremely large vacuole. Both R and F cells were columnar, and F cells were separated by two to three serial R cells. R cells contained small vacuoles, but had no extremely large vacuole in the cytoplasm. Two neighbouring R cells established contact by septate junctions. Many microvilli were present on the surface of the plasmalemma of R cells. Endocytotic vesicles were frequently observed in apical regions of the R cells. F cells were hyperbasophilic and argyrophilic, and contained abundant rough endoplasmic reticulum. E cells were small and contained scant cytoplasm and we rarely observed organelles in these cells. In addition, many vesicae were present in the lumen of the hepatopancreatic tubules.

Noise Induces Hypothyroidism and Gonadal Dysfunction Via Stimulation of Pineal–Adrenal Axis in Chicks

Noise is a world-wide problem that causes nervous, endocrine and cardiovascular disorders, and eventually health hazards in humans and animals. Objective of the current work is to investigate endocrine interaction in noise stress, which subsequently affects other endocrine functions including gonads in a poultry bird like chicks. Gravimetric, ultrastructural and hormonal status of the endocrine organs were examined to ascertain the effects of noise stress. Acute noise at 60 dB had no effect, but at 80 and 100 dB each for 3 h, increased pineal and serum serotonin, and adrenal and serum corticosterone, epinephrine and norepinephrine concentrations, without any change in thyroid or gonadal hormones. Chronic noise exposure at 60, 80 and 100 dB each for 6 h, daily for 7 days, drastically disturbed normal behavior, and quantum of food consumption and water intake. Chronic exposure also significantly decreased body weight including thyroid, ovary and testis weight, and increased adrenal weight. Noise stress caused ultrastructural changes leading to stimulations of pinealocytes (with abundance of rough endoplasmic reticulum and mitochondria), adrenocortical cells (enlarged nuclei and abundance of smooth endoplasmic reticulum) and adrenomedullary cells (enlarged nuclei with presence of chromaffin granules) were observed in noise stress. Additionally, pineal and serum serotonin, N-acetyl serotonin and melatonin, and adrenal and serum corticosterone, epinephrine and norepinephrine levels were significantly elevated following chronic noise exposure. Contrarily, thyroid activity was suppressed with atrophied thyroid follicles followed by declined levels of serum T3 and T4 with elevation of TSH level. Simultaneously, serum 17β-estradiol (E2) and testosterone (T) concentrations were also significantly declined in all the doses of chronic noise. These changes were dose dependent of noise exposure. The findings suggest that (a) adrenal and pineal glands respond primarily to noise and secondarily act on other endocrine organs including gonads in chicks, (b) adrenal directly and/or indirectly causes thyroid and gonadal dysfunctions via pineal following noise exposure in chicks.

General morphology and ultrastructure of the female reproductive apparatus of Trichomalopsis shirakii crawford (Hymenoptera, Pteromalidae).

The morphology and ultrastructure of the female reproductive system were examined for a larval-pupal parasitoid Trichomalopsis shirakii Crawford of Oulema oryzae Kuwayama using light and electron microscopes. The reproductive system includes two ovaries, two pairs of accessory glands, an unbranched venom gland, a large venom reservoir and a Dufour gland. Each ovariole contains follicles and oocytes at different stages of maturation. A fibrous layer covers the surface of mature egg. The accessory glands are made up of a layer of secretory cells surrounded by muscle fibers. In these secretory cells, numerous mitochondria, electron-dense secretory granules and vesicles filled with dense granular particles are present. These granular particles appear as virus-like particles (VLPs). The venom gland consists of a single layer of secretory cells which are organelle rich with abundant rough endoplasmic reticulum, mitochondria and vesicular organelles, a layer of duct cells and an inner intima. The reservoir consists of a muscular sheath, epidermal cells with few organelles and an intima layer. The Dufour gland has a relatively large lumen surrounded by a single layer of columnar epithelial cells which are characterized by clusters of smooth endoplasmic reticulum and lipid droplets. Aside from the venom, the fibrous layer coating the egg and the granular particles which may be VLPs have been discovered in our study. They may serve as one of the parasitoid-associated factors in their host-parasitoid relationship and play a role in host immune suppression. Microsc. Res. Tech. 79:625-636, 2016. © 2016 Wiley Periodicals, Inc.

Anatomy and Ultrastructure of Male Reproductive System in Two LeafhoppersCicadella viridisandKolla paulula(Hemiptera: Auchenorrhyncha: Cicadellidae)

The morphology and ultrastructure of the male reproductive system were investigated in two species of sharpshooter leafhoppers, Cicadella viridis (L.) and Kolla paulula (Walker), using light microscopy and transmission electron microscopy. The gross morphology and ultrastructure of the male reproductive system in the two species is similar to those of other Cicadellidae and related Auchenorrhyncha. The two species differ in the number and shape of testicular follicles, the shape of the seminal vesicle, and the size and color of the accessory gland. The testicular follicle consists of the epithelium lying on a thick basal lamina surrounded by a connective sheath, and a wide lumen filled with germ cells. Large numbers of vesicles and granular materials are observed in the epithelial cell. The two seminal vesicles close-set under a common tunica are composed of the basal lamina, the thick muscular-connective sheath, a mono-layered epithelium, and the vesicular lumen. The vesicles and granules are extensive in the cytoplasm of the flattened epithelial cell, whose apical surface usually has numerous microvilli. The accessory gland is made up of thin muscular-connective sheath, the basal lamina, the epithelium, and the tubular lumen. The epithelial cell with secretory granules has abundant rough endoplasmic reticulum and small vesicles, and its cytoplasm abounds with arrays of three types of granules. Spermiogenesis and sperm ultrastructure of K. paulula was also observed, whose sperm can be distinguished from those of other Cicadellidae by the accessory bodies and mitochondrial derivatives with gap region.

Spontaneous cutaneous soft tissue sarcoma with differentiation into fibroblasts in a Sprague-Dawley rat

A small mass with an ulcer was found in the skin of the dorsal cervix of a 7-month-old male Sprague-Dawley rat. Histologically, the central region of the tumor showed a high cellular density with oval-shaped tumor cells arranged in an alveolar pattern and thin collagen fiber bundles. The peripheral region of the tumor had a low cellular density with short spindle- or polygonal-shaped tumor cells surrounded by abundant collagen fiber bundles. Immunohistochemically, the tumor cells were strongly positive for vimentin and proliferating cell nuclear antigen, and a portion of the short spindle- or polygonal-shaped cells located in the peripheral region of the tumor were positive for S100A4. However, the tumor cells were negative for alpha-smooth muscle actin, desmin, S100, chromogranin A, neurofilament, CD68, Iba-1, cytokeratin 20, von Willebrand factor, melanosome, and anti-melanoma. Electron microscopically, the tumor cells had an abundance of rough endoplasmic reticulum, the Golgi apparatus, and a few intracellular collagen fibrils, showing fibroblastic features. Considering the lack of diagnostic differentiation, the tumor was diagnosed as an undifferentiated malignant mesenchymal tumor and classified as a soft tissue sarcoma with differentiation into fibroblasts in a portion of the tumor cells.

Zonal Changes in the Ultrastructure of the Epididymal Principal cell of the Greater Cane Rat (Thryonomys swinderianus)

This study presents the varying ultrastructural characteristics of the principal cell along the different zones of the epididymis of the greater cane rat. Ten sexually mature male cane rats with known medical and reproductive history were perfusion-fixed using Karnovsky fixative (phosphate buffered 2% paraformaldehyde – 2.5% glutaraldehyde fixative at pH 7.4). Epididymal samples were then obtained, processed for ultrastructural analysis and examined under the transmission electron microscope. Our findings showed that the cane rat epididymis has four distinct regions – initial segment, caput, corpus and cauda epididymides. These regions are further subdivided into discrete subregional zones based on the cytological characteristics of the principal cell in each region. The principal cell in the proximal initial segment showed abundant rough endoplasmic reticulum and extensive Golgi apparatus arranged in a peculiar whorl shape predominantly in the apical cytoplasm with small vesicles, dense granules and multivesicular bodies scattered in and around the whorls. The principal cell of the distal initial segment is characterized by multivesicular bodies, small and coated vesicles as well as numerous flat and whorl-shaped cisternae of rough endoplasmic reticulum and dense-core mitochondria. In the caput epididymis, the principal cell contains more of lipid vacuoles, while in the corpus, it has prominent dense bodies of various sizes at its supranuclear area. These dense bodies tend to increase in the principal cells of the cauda epididymis. The transition between regions was however observed to be gradual with overlapping of morphological characteristics between two adjacent regions. These ultrastructural diversities exhibited by the epididymis along its length point to a corresponding functional diversity and do dictate the overall intra-luminal environment necessary for sperm maturation in the cane rat.

Making maxillary barbels with a proximal-distal gradient of Wnt signals in matrix-bound mesenchymal cells.

The evolution of specific appendages is made possible by the ontogenetic deployment of general cell signaling pathways. Many fishes, amphibians and reptiles have unique skin appendages known as barbels, which are poorly understood at the cellular and molecular level. In this study, we examine the cell arrangements, cell division patterns, and gene expression profiles associated with the zebrafish maxillary barbel, or ZMB. The earliest cellular organization of the ZMB is an internal whorl of mesenchymal cells in the dermis of the maxilla; there is no epithelial placode, nor any axially-elongated epithelial cells as expected of an apical ectodermal ridge (AER). As the ZMB develops, cells in S-phase are at first distributed randomly throughout the appendage, gradually transitioning to a proliferative population concentrated at the distal end. By observing ZMB ontogenetic stages in a Wnt-responsive transgenic reporter line, TCFsiam, we identified a strongly fluorescent mesenchymal cell layer within these developing appendages. Using an in vitro explant culture technique on developing barbel tissues, we co-localized the fluorescent label in these cells with the mitotic marker EdU. Surprisingly, the labeled cells showed little proliferation, indicating a slow-cycling subpopulation. Transmission electron microscopy of the ZMB located these cells in a single, circumferential layer within the barbel's matrix core. Morphologically, these cells resemble fibroblasts or osteoblasts; in addition to their matrix-bound location, they are identified by their pancake-shaped nuclei, abundant rough endoplasmic reticulum, and cytoplasmic extensions into the surrounding extracellular matrix. Taken together, these features define a novel mesenchymal cell population in zebrafish, the "TCF(+) core cells." A working model of barbel development is proposed, in which these minimally mitotic mesodermal cells produce collagenous matrix in response to ectodermally-derived Wnt signals deployed in a proximal-distal gradient along the appendage. This documents a novel mechanism of vertebrate appendage outgrowth. Similar genetic signals and cell behaviors may be responsible for the independent and repeated evolution of barbel structures in other fish species.

Location, morphology and function of nephrocytes in termites

Insect nephrocytes are cells bathed in hemolymph and considered to have an excretory function. These cells have ambiguous nomenclature and are understudied in termites. This study is the first report on the occurrence, morphology and function of nephrocytes in different termite castes. Cytological characteristics in specific developmental stages and castes enable physiological functions to be inferred. Perforate diaphragms indicate a role in filtration, while the extensive peripheral invaginations of the cell membrane suggest active endocytosis. A sequence of morphologies in putative digestive vacuoles infers a lysosomal system and the occurrence of phosphatases suggests a function involving detoxification of substances sequestered from hemolymph. Pericardical nephrocytes took up the dye trypan blue injected in live termites, suggesting their activity connected to the filtration of the hemolymph. Additionally, histochemical tests showed the existence of stored proteins in their cytoplasm. These cells present a well-developed Golgi apparatus and abundant rough endoplasmic reticulum, consistent with protein synthesis. This study highlights the importance of nephrocytes in Isoptera and opens perspectives for further research of these cells.