Electron-lucent Cytoplasm Research Articles

Characterization of the pancreas of common pheasant (Phasianus colchicus): A light and transmission electron microscope study.

The present work was carried out to investigate the structure and ultra structure of the pancreas in the common pheasant (Phasianus colchicus). Totally, five healthy adult pheasant were used. The pancreas was assessed using histochemistry and transmission electron microscopy (TEM). The pancreas was composed of four lobes: dorsal, ventral, third, and splenic lobes. These lobes emptied into ascending duodenum through three excretory ducts as: ventral duct, splenic duct, and a common duct for dorsal and third lobes. The exocrine pancreas was constituted of pyramidal-shaped acinar cells with aggregation of zymogen granules at their apical cytoplasm. The endocrine pancreas was identified as large islet of Langerhans as α islets and small islets as β ones. No mixed islet was observed. At the level of TEM, two types of acinar cells were distinguished: Dark cells with electron dense cytoplasm, and indented nucleus, Light cells with electron lucent cytoplasm, and regular nucleus. The α islets were mainly constituted by A and D cells, whereas the β islets principally contained B cells and a few A cells. No D cells were identified in β islets. B cells were characterized by their polymorphic granules which were surrounded by a narrow halo zone. The granules of D cells were quite different. These cells contained large spherical granules with lower density as compared to the A or B granules surrounded by a limiting membrane. In conclusion, the pancreas of the common pheasant has a species-specific feature which must be considered in phylogenic studies. RESEARCH HIGHLIGHTS: The common pheasant's pancreas was composed of four lobes as dorsal, ventral, third, and splenic lobe. There were three excretory ducts. Ventral duct for ventral lobe, a common duct for both dorsal and third lobes, and a distinct splenic duct for splenic lobe. The exocrine acini were composed of two distinct types of cells: dark cells and light cells. The large alpha islets were composed of alpha cells and a few numbers of delta cells and small beta islets were composed of beta cells and a few numbers of alpha cells.

Exposure to stressors and antimicrobials induces cell-autonomous ultrastructural heterogeneity of an intracellular bacterial pathogen.

Despite their clonality, intracellular bacterial pathogens commonly show remarkable physiological heterogeneity during infection of host cells. Physiological heterogeneity results in distinct ultrastructural morphotypes, but the correlation between bacterial physiological state and ultrastructural appearance remains to be established. In this study, we showed that individual cells of Salmonella enterica serovar Typhimurium are heterogeneous in their ultrastructure. Two morphotypes based on the criterion of cytoplasmic density were discriminated after growth under standard culture conditions, as well as during intracellular lifestyle in mammalian host cells. We identified environmental conditions which affect cytoplasmic densities. Using compounds generating oxygen radicals and defined mutant strains, we were able to link the occurrence of an electron-dense ultrastructural morphotype to exposure to oxidative stress and other stressors. Furthermore, by combining ultrastructural analyses of Salmonella during infection and fluorescence reporter analyses for cell viability, we provided evidence that two characterized ultrastructural morphotypes with electron-lucent or electron-dense cytoplasm represent viable cells. Moreover, the presence of electron-dense types is stress related and can be experimentally induced only when amino acids are available in the medium. Our study proposes ultrastructural morphotypes as marker for physiological states of individual intracellular pathogens providing a new marker for single cell analyses.

Electron microscopic study on the effect of chronic fluoxetine treatment on pituitary gland and the possible therapeutic effect of adipose-derived mesenchymal stem cells in adult male albino rats

ABSTRACT Background: Adipose-derived mesenchymal stem cells (ADSCs) have therapeutic potential for the treatment of a variety of disorders due to their self-renewal and multipotential differentiation capabilities. Aim of the work: This study was planned to demonstrate the electron microscopic structure of the pituitary gland after chronic fluoxetine treatment and the possible therapeutic effect of ADSCs. Materials and methods:Thirty healthy male adult albino rats were classified into Control group (Group I). Fluoxetine treated (Group II) received 24 mg/kg/day of fluoxetine dissolved in 1.0 mL of tap water once a day. Fluoxetine group treated with ADSCs (Group III) received fluoxetine as group (II) for 30 days and then was injected once by ADSCs at a dose of 1 × 106 cells/rat in the tail vein suspended in 0.5 ml of phosphate-buffered saline (PBS). Recovery group (Group IV) received fluoxetine for 30 days and then received no treatment till the end of the experiment. Results: The ultrastructural observations of the fluoxetine-treated group revealed major histological changes in both the pars distalis and nervosa. Pars distalis revealed cells with different shapes, sizes, nuclei, and variable profiles of the cytoplasm. Pars nervosa, on the other hand, revealed pituicytes with electron-lucent cytoplasm and small apoptotic nuclei. Administration of ADSCs greatly improved the microscopic appearance of cells, while the recovery group showed similar histological changes as the fluoxetine group. Conclusion: Fluoxetine caused various deleterious changes in the pituitary gland of albino rats, as evidenced by electron microscopy. These changes were almost corrected by the ADSCs treatment. .

Regenerative capacity of bone marrow stem cells on aged albino rat’s parotid excretory duct

ObjectiveTo appraise structural features of parotid excretory duct during senility and probable effect of bone marrow-mesenchymal stem cells (BM-MSCs). DesignA total of 14 healthy male albino rats were used. Seven adult rats (24–34-week-old) represented the control group (Group I). Seven senile rats (72–80-week-old) were utilized in which the left parotid gland served as “Old” (Group II) and were injected by 0.2 ml phosphate buffered saline; the right side represented “Old treated” (Group III) and got local injection of 1–1.5 million allogeneic BM-MSCs. One month later, glands were dissected and assessed structurally, ultra-structurally and statistically. ResultHistologically, Group I showed normal duct histology. In Group II duct lining lost its pseudostratification which was recovered in Group III. PCNA immunolocalization showed moderate reactivity in Group I, negative to mild reaction in Group II, and strong reaction in some of Group III cells. Ultra-structural features of Group I were ordinary in which basal cell had a large flat nucleus, and dark and light cells showed electron-dense cytoplasm and electron-lucent cytoplasm respectively. Tuft cell displayed long microvilli. Mucous droplets filled goblet cell. Group II revealed an apparent reduction in cells size, organelles and absence of tuft cell. In Group III all cell types were detected and they recovered their organelles, cell and nucleus shape. The highest mean area% of PCNA immunoreactivity was in Group I followed by Group III then Group II. ConclusionsAging has a deteriorating effect on structure and ultra-structure of parotid gland excretory duct that could be amended by BM-MSCs.

Histomorphology of the Malpighian Tubules and the Chemical Composition of the Spherocrystals in the Tubule Epithelial Cells of Adult Leptophyes albovittata (Kollar, 1833) (Orthoptera, Tettigoniidae).

In insects, the number, cytological and histological structures, and the spherocrystals of the Malpighian tubules (MTs) can vary considerably in different insect groups. These differences are considered important because they can be used as taxonomic characters. For this purpose, the ultrastructure of the MT epithelial cells in Leptophyes albovittata (Kollar, 1833) (Orthoptera, Tettigoniidae) was examined by light microscopy, scanning electron microscopy, and transmission electron microscopy. The wall of each tubule consists of a single layer of cells. These cells have round-shaped nuclei. Two different cell types were demonstrated in the tubule cell. These are cells that have electron-dense cytoplasm and electron-lucent cytoplasm. It was observed that the cytoplasm of these cells has many spherocrystals. The chemical composition of the spherocrystals was found to be high in carbon, phosphorus, and manganese in tubule cells.

Identification of the hallmarks of necroptosis and ferroptosis by transmission electron microscopy

Apoptosis is the prototype for a regulated form of cell death, but recent studies have revealed other types of regulated forms of cell death, including necroptosis and ferroptosis. The molecular mechanisms underlying the execution of these processes have been intensively investigated, yet the hallmarks of their morphology are not fully understood. Here, we report that electron lucent cytoplasm was a common feature of both necroptosis and ferroptosis, which was consistent with cytoplasmic vacuolization due to a defect in the cytoplasmic membrane integrity. Notably, the perinuclear space was dilated in necroptosis, but such dilation did not occur in ferroptosis. Cells undergoing ferroptosis, but not necroptosis, exhibited an electron lucent nucleus. We previously reported that one of the nuclear danger-associated molecular patterns (DAMPs), high mobility group box (HMGB)1, is rapidly released from the nucleus to the extracellular spaces of cells undergoing necroptosis through the ruptured nuclear and cytoplasmic membrane. Via time-lapse imaging of cells stably expressing HMGB1 fused to a fluorescence protein, we found that HMGB1 was also released from the nucleus to the cytosol, and then eventually released into the extracellular spaces in cells undergoing ferroptosis. Thus, nuclear membrane damage was induced prior to cytoplasmic membrane rupture in ferroptosis. Thus, dilation of the perinuclear space and an electron lucent nucleus may be the hallmarks of necroptosis and ferroptosis, respectively.

Fluoxetine ameliorates adult hippocampal injury in rats after early maternal separation. A biochemical, histological and immunohistochemical study

ABSTRACTThe mother-infant relation is important for brain development and maturation. To investigate hippocampus changes, we used 18 male rat pups from three dams. Pups were divided into a maternal care (control) group, a maternal separation (MS) group and a MS plus fluoxetine (MS + Fl) treated group. On postnatal day 22, pups were weaned and their serum corticosterone level measured. At 2 months, the hippocampus was removed and processed for histological, immunohistochemical and ultrastructural study. MS caused significant elevation of serum corticosterone level and a significant decrease in the thickness of the pyramidal and granular layers of the cornu ammonis 3 (CA3) and dentate gyrus (DG) areas of the hippocampus. Both CA3 and DG areas exhibited degenerative changes in nerve cells, which were shrunken with pyknotic nucleus and darkly stained cytoplasm. Electron microscopy showed condensed chromatin, degenerated mitochondria, cytoplasmic vacuoles and electron lucent cytoplasm with loss of most polyribosomes. Immunohistochemical staining showed significantly increased numbers of glial fibrillary acid protein-positive cells in the CA3 and DG, and numbers of Ki-67stained cells in the DG in the MS group compared to the control group. All adverse changes were ameliorated in the MS + Fl group. Our findings corroborate the importance of the mother-infant relation to hippocampal development and demonstrate a protective role for Fl in MS pups.

Shikonin-induced necroptosis in nasopharyngeal carcinoma cells via ROS overproduction and upregulation of RIPK1/RIPK3/MLKL expression.

Objective: Shikonin has inhibitory effects against nasopharyngeal carcinoma that are mediated through the apoptotic pathway. However, necroptosis signaling pathways may enable the elimination of apoptosis-resistant cancers when induced with targeted therapeutic agents. Thus, there is a need to clarify whether shikonin can cause necroptosis in nasopharyngeal carcinoma and to elucidate the underlying mechanisms.Methods: In this study, we used the nasopharyngeal carcinoma cell line 5-8F and a 5-8F xenograft mouse model to evaluate the anticancer effects of shikonin. The viability and morphology of cells treated with shikonin were evaluated using CCK-8 assay and transmission electron microscopy, respectively. In addition, the expression levels of RIPK1, RIPK3, and MLKL were analyzed by western blotting, and the activities of caspase-3 and caspase-8 and levels of reactive oxygen species (ROS) were assessed.Results: Shikonin exhibited a strong inhibitory effect on 5-8F cells in vitro and in vivo. The shikonin-treated 5-8F cells presented an electron-lucent cytoplasm, loss of plasma membrane integrity, and an intact nuclear membrane, indicating that shikonin induced necroptosis. Shikonin-induced cell death was inhibited by necrostatin-1. Moreover, RIPK1, RIPK3, and MLKL were upregulated by shikonin in a dose-dependent manner. Furthermore, shikonin significantly inhibited tumor growth in the 5-8F xenograft mouse model.Conclusion: Shikonin induced 5-8F cell death via increased ROS production and the upregulation of RIPK1/RIPK3/MLKL expression, resulting in necroptosis. Thus, shikonin may represent a novel agent to treat nasopharyngeal carcinoma.

The synthetic peptide LyeTxI-b derived from Lycosa erythrognatha spider venom is cytotoxic to U-87 MG glioblastoma cells.

Antimicrobial peptides present a broad spectrum of therapeutic applications, including their use as anticancer peptides. These peptides have as target microbial, normal, and cancerous cells. The oncological properties of these peptides may occur by membranolytic mechanisms or non-membranolytics. In this work, we demonstrate for the first time the cytotoxic effects of the cationic alpha-helical antimicrobial peptide LyeTx I-b on glioblastoma lineage U87-MG. The anticancer property of this peptide was associated with a membranolytic mechanism. Loss of membrane integrity occurred after incubation with the peptide for 15min, as shown by trypan blue uptake, reduction of calcein-AM conversion, and LDH release. Morphological studies using scanning electron microscopy demonstrated disruption of the plasma membrane from cells treated with LyeTx I-b, including the formation of holes or pores. Transmission electron microscopy analyses showed swollen nuclei with mild DNA condensation, cell volume increase with an electron-lucent cytoplasm and organelle vacuolization, but without the rupture of nuclear or plasmatic membranes. Morphometric analyses revealed a high percentage of cells in necroptosis stages, followed by necrosis and apoptosis at lower levels. Necrostatin-1, a known inhibitor of necroptosis, partially protected the cells from the toxicity of the peptide in a concentration-dependent manner. Imaging flow cytometry confirmed that 59% of the cells underwent necroptosis after 3-h incubation with the peptide. It is noteworthy that LyeTx I-b showed only mild cytotoxicity against normal fibroblasts of human and monkey cell lines and low hemolytic activity in human erythrocytes. All data together point out the anticancer potential of this peptide.

Morphological, histological and ultrastructural studies on the exocrine pancreas of goose

The present work was aimed to study the morphological and histological features of goose pancreas and to investigate the ultrastructure of pancreatic acini. This study was conducted on the pancreas of ten healthy mature birds of goose. The pancreas was excised from the duodenum rapidly after slaughter of the birds. The specimens were fixed in 10% buffered neutral formalin then processed for light and electron microscopic study. The macroscopic observations revealed that goose pancreas was located in the right side of the abdomen between the ascending and descending loops of duodenum. It was formed from dorsal, splenic, ventral and third lobes. The histological observations revealed that the pancreas was formed of lobules of serous acini. The secretory acinus unit was appearing as a single spherical mass composed of many serous cells surrounding narrow lumen. The pyramidal acinar cells appeared bizonal structure; the basal basophilic cytoplasm and apical acidophilic cytoplasm. Centroacinar cells were slightly smaller cells that appeared brighter than the acinar cells and were located in the center of the lumen of the acinus. The duct system was well developed began with the centroacinar cells. Underneath electron microscope, the acinar cells have been two kinds, the electron dense acinar cells with electron dense cytoplasm and heterochromatic nuclei and the electron lucent acinar cells, which characterized by means of electron lucent cytoplasm, and their nuclei had considerable euchromatin, abundant endoplasmic reticulum, mitochondria and numerous zymogen granules, and considered active cells.

The mature and immature spermatozoa of the free-living marine nematode Daptonema sp. (Nematoda: Monhysterida: Xyalidae)

The immature spermatozoa stored in the testis and female postvulval uterine sac (PUS), and mature spermatozoa from the uterus of the free-living marine nematode Daptonema sp. (Monhysterida: Monhysterina: Xyalidae) were studied. The spermatozoa have a nucleus without a nuclear envelope. The central cytoplasm of the immature spermatozoa from the testis and the distal part of the PUS is occupied by a mass of pale fibrous bodies (FB) surrounded by mitochondria and osmiophilic membranous organelles (MO). The spermatozoa in the proximal half of PUS have a wide peripheral layer of electron lucent filamentous cytoplasm. The uterus lumen contains an aggregation of mature spermatozoa of which the periphery is transformed into pseudopods. The FB replaced by a voluminous electron-lucent halo bounded by a continuous layer of MO, mitochondria and fibrous matter. The MO may be intact, but numerous MO are fused with the plasma membrane, having been transformed into transparent pouches, each one opening to the exterior via a pore. Ultrastructural data showed that the activation is regulated in the female when spermatozoa migrate toward the uterus and transform into amoeboid mature spermatozoa. In general, the spermatozoa of Daptonema sp. and some other Monhysterina closely resemble those of the taxa belonging to the order Rhabditida. However, the `rhabditid' pattern of spermatozoon structure and development is most likely the plesiomorphic state in Rhabditida and close sister groups.

Unique characterization of Langerhans cells in the spleen of the African catfish (<em>Clarias gariepinus</em>).

The African catfish (Clarias gariepinus) has increasingly become an economically important food source especially in Africa, Asia and Europe, with exports extending to countries throughout the world. In the last 25 years, aquaculture of this species has been particularly effective with large increases in production and this is in part due to the catfish being highly resistant to disease. In order to further understand the immune system of the catfish, the spleen was investigated using a number of staining, immunohistochemical, light and transmission electron microscope techniques in order to verify the histological features of this organ. The gross histological features of the spleen confirmed the presence of a capsule containing numerous collagen fibers surrounded the spleen of the African catfish. Melanomacrophage centers, lymphocytes and surrounding arterial vessels were the main components of the white pulp whilst the red pulp contained sinusoids, capillaries and splenic cords of erythrocytes, macrophages and lymphocytes. Transmission electron microscopy identified Langerhans-like cells which were irregular to ovoid in shape with an electron lucent cytoplasm. The cells were characterized by the presence of numerous Birbeck-like granules, varying in shape from oval, round, rod to racket shaped granules. In total, three types of Birbeck-like granules were identified. The first type had heterogenic content, the second type were cored granules and the third type were racket shaped granules. Some of the racket shaped granules were enlarged and contained granular content. The Langerhans-like cells were further identified and characterised by showing a positive reaction with antibodies to S100 and CD1a. The existence of Langerhans-like cells within the spleen helps to identify the components of the immune system within the African catfish.

The possible protective effect of Nigella sativa seeds on cisplatin-induced acute nephrotoxicity in the rat renal cortex (Histological and Electron Microscopic study)

Introduction Cisplatin is one of the most effective chemotherapeutic agents for the treatment of various tumors. However, cisplatin-induced nephrotoxicity is one of the serious side effects in humans. Aim of the work The aim of this study was to clarify the possible protective effect of Nigella sativa seeds on cisplatin-induced acute nephrotoxicity. Materials and methods A total of 24 male albino rats were used. The rats were divided into four groups: group I was the control group; group II received N. sativa seeds; group III received cisplatin through intraperitoneal injection as a single dose; and group IV received N. sativa seeds orally 3 days before, concomitant with, and 5 days after cisplatin. At the end of the experiment, blood samples were collected for the estimation of serum creatinine and malondialdehyde. Renal specimens were processed for light and electron microscopic examination. Results Light microscopic examination of renal cortical sections from group III showed areas with interstitial hemorrhage. Areas with destruction and loss of tubules were detected. Other areas revealed tubules with desquamated cells. Some cells revealed vacuolated cytoplasm and pyknotic nuclei. Partial or complete loss of the brush border of some tubules was seen. Some glomeruli appeared collapsed and others with thickening of the basement membranes. There was a statistically significantly increased deposition of collagen fibers between the cortical tubules. Ultrastructural examination showed variable degrees of affection of tubular cells, including loss of apical microvilli and loss of basal enfoldings of the basement membrane. Few scattered mitochondria were distributed in more electron lucent cytoplasm. There was thickening of the basement membrane of the parietal layer of the renal corpuscle and of the glomerular capillaries. Group IV rats showed attenuated cisplatin-induced renal cortical changes and improved biochemical data. Conclusion N. sativa seeds provided an ameliorative effect on acute cisplatin-induced renal cortical toxicity and it could be recommended as an adjuvant therapy for patients treated with cisplatin.

HISTOLOGICAL, HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL STUDIES ON THE PARAVENTRICULAR AND SUPRAOPTIC NUCLEI OF THE HYPOTHALAMUS IN THE ADULT NEW ZEALAND RABBITS

The present investigation aims to give a detailed histomorphological feature of the anterior group of hypothalamus of adult New Zealand rabbits in both sexes. Specimens were prepared to be examined microscopically by using light and transmission electron microscope. The obtained results revealed that, the anterior group of the hypothalamus composed of paraventricular (PVN) and supraoptic nuclei (SON). The paraventricular nucleus was located on either sides of the 3rd ventricle. It consisted of different-shaped neurons which appeared in the form of clusters and irregular groups intermingled with nerve fibers associated with neuroglia cells and permeated by blood capillaries. Ultrastructurally, the neurons appeared polyhedral in shape contained large eccentric euchromatic nucleus and electron lucent cytoplasm contained many mitochondria, rER, Golgi apparatus, numerous ribosomes and some secretory granules. On the other hand, the supraoptic nucleus was located dorsolateral to the optic chiasma and consisted of two portions; thin medial and thick lateral one. The neurons of the thin medial part appeared pyramidal in shape with vesicular oval eccentric nuclei and lightly stained cytoplasm, while that of the thick lateral one showed irregular groups or rows of oval and pyriform shaped cells contained vesicular rounded eccentric nuclei. Ultrastructurally, the neurons of the thick lateral part of SON appeared pyriform in shape with spherical eccentric euchromatic nucleus in electron lucent cytoplasm showed intensive network of rER, many mitochondria, Golgi apparatus, numerous free ribosomes and few secretory granules. The cytoplasmic granules of the PVN and SON neurons gave positive reaction with all nonspecific and specific stains used. Also, they gave positive immunoreactions when subjected to Anti-CGA and Anti-NSE antibodies. There were no microscopic structural differences correlated to neither sex nor age of studied animals.

Changes in the midgut diverticula in the harvestmen Amilenus aurantiacus (Phalangiidae, Opiliones) during winter diapause

The harvestmen Amilenus aurantiacus overwinter in diapause in hypogean habitats. The midgut diverticula have been studied microscopically (light microscopy, TEM) and biochemically (energy-storing compounds: lipids and glycogen) to analyze changes during this programmed starvation period. Throughout the investigated period, the epithelium of the midgut diverticula is composed of secretory cells, digestive cells and adipocytes. Additionally, after the middle of overwintering, the excretory cells appear, and two assemblages of secretory cells are present: the SC1 secretory cells are characterized by electron-dense cytoplasm with numerous protein granules, and the SC2 cells by an electron-lucent cytoplasm with fewer protein granules. The autophagic activity is observed from the middle of overwintering, indicating its vital role in providing nutrients during this non-feeding period. Lipids and glycogen are present in the midgut diverticula cells, except in the excretory cells. Measurements of the lipid droplet diameters and the lipid quantities yielded quite comparable information on their consumption. Lipids are gradually spent in both sexes, more rapidly in females, owing to ripening of the ovaries. Glycogen rates decrease towards the middle, and increase just before the end of overwintering, indicating that individuals are preparing for the epigean active ecophase.

Ultrastructural studies on the midgut of biting midge Forcipomyia nigra (Winnertz) (Diptera: Ceratopogonidae)

Biting midges belonging to the genus Forcipomyia are known to be hematophagous, predatory or saprophagous. Different stages of Forcipomyia nigra midges were investigated to provide a description of midgut ultrastructure. Larvae feeding on decaying organic matter possess simple, straight alimentary tracts whose middle regions are the longest. TEM studies of the larval midgut epithelium reveal that digestive cells show different ultrastructure depending on their age. The older cells with electron-dense cytoplasm degenerate while the younger ones with electron-lucent cytoplasm remain active in digestion. In saprophagous females, the ultrastructure of midgut epithelium changes according to the age of flies. Oogenesis induces degeneration of digestive cells and utilization of reserve material accumulated by them. The midgut epithelia of male midges consist of digestive and regenerative cells that show no evidence of cell degeneration as observed in females. Our results demonstrate differences between midgut digestive cells of males and females.

Ultrastructure of the oviductal mucosa of Leptodactylus chaquensis. Analysis of the preovulatory and postovulatory periods.

In the present study we analysed the ultrastructural characteristics of the oviductal mucosa of Leptodactylus chaquensis during the preovulatory period and immediately after ovulation. Epithelial secretory cells, ciliated cells, basal cells and glandular secretory cells are described. During the preovulatory period, the oviduct exhibits its maximum degree of development at both the epithelial and the glandular levels, with numerous secretory cells that contain a large number of secretory granules whose contents are released into the oviductal lumen by apocrine and exocytotic secretory processes. The secretory cells present throughout the oviduct display considerable variability in the characteristics of their secretory granules, which show different shapes, sizes, organization of the material contained and electron density. The different cell types are distributed following a characteristic pattern for each oviductal zone, thus creating an ultrastructural mosaic along the oviduct. During the postovulatory period, the number of secretory cells decreases and the remaining ones exhibit a marked reduction in secretory granules. Ciliated cells show a typical ultrastructural organization that is not modified throughout the reproductive cycle. Basal cells, located at the basal region of the epithelium, are characterized by their heterochromatic nuclei and electron-lucent cytoplasm, while glandular secretory cells exhibit oval, round or polyhedric granules, most of them with a prominent core. Our results, which indicate a high heterogeneity of secretory cell contents, allow us to suggest differential synthesis and secretion of specific products in each oviductal zone.

Aedes aegypti midgut remodeling during metamorphosis

The Aedes aegypti midgut is restructured during metamorphosis; its epithelium is renewed by replacing the digestive and endocrine cells through stem or regenerative cell differentiation. Shortly after pupation (white pupae) begins, the larval digestive cells are histolized and show signs of degeneration, such as autophagic vacuoles and disintegrating microvilli. Simultaneously, differentiating cells derived from larval stem cells form an electron-dense layer that is visible 24h after pupation begins. Forty-eight hours after pupation onset, the differentiating cells yield an electron-lucent cytoplasm rich in microvilli and organelles. Dividing stem cells were observed in the fourth instar larvae and during the first 24h of pupation, which suggests that stem cells proliferate at the end of the larval period and during pupation. This study discusses various aspects of the changes during midgut remodeling for pupating A. aegypti.

Morphology of Non-Sensory Epithelium during Post-natal Development of the Rabbit Vomeronasal Organ

The vomeronasal organ (VNO), because of its ability to detect pheromones, has an important role in many social and sexual behaviours in mammals. It also mediates defensive behaviours through detection of protein pheromone homologues. A detailed morphological description of the post-natal development of the 'non-sensory' epithelium (NSE) of the female rabbit is recorded. Histological techniques were used to study the NSE of the VNO in post-natal development of female rabbits. The study focused on the following post-natal ages: newborn, 1 week, 2 weeks and 1 month (five animals each) beside to two adult animals. The rabbit VNO was surrounded externally by bony capsule and internally by cartilaginous capsule. NSE was pseudostratified columnar partially ciliated epithelium without goblet cells. In addition to basal cells, NSE contained ciliated and three types of non-ciliated columnar cells (dark, pale and light). At birth, dark cells may have primary cilia. By 1 month, the cytoplasm became lighter with less free ribosomes. The pale cells had electron-lucent cytoplasm, which contained a few organelles. Mitotic figures were observed in basal and columnar cells, particularly during the first 2 weeks of post-natal development. Light columnar cells were common during the first week. Numerous leucocytes and a few nerve endings were detected intra-epithelial. Scanning electron microscope revealed a gradual increase in height of microvilli of non-ciliated cells. Ciliated cells had cilia and microvilli. Cells were arranged singly, in clumps or in a dense population of cells. The rabbit VNO-NSE had a unique morphological structure.

Shikonin Kills Glioma Cells through Necroptosis Mediated by RIP-1

Background and PurposeShikonin was reported to induce necroptosis in leukemia cells, but apoptosis in glioma cell lines. Thus, it is needed to clarify whether shikonin could cause necroptosis in glioma cells and investigate its underlying mechanisms.MethodsShikonin and rat C6 glioma cell line and Human U87 glioma cell line were used in this study. The cellular viability was assayed by MTT. Flow cytometry with annexin V-FITC and PI double staining was used to analyze cellular death modes. Morphological alterations in C6 glioma cells treated with shikoinin were evaluated by electronic transmission microscopy and fluorescence microscopy with Hoechst 33342 and PI double staining. The level of reactive oxygen species was assessed by using redox-sensitive dye DCFH-DA. The expressional level of necroptosis associated protein RIP-1 was analyzed by western blotting.ResultsShikonin induced cell death in C6 and U87 glioma cells in a dose and time dependent manner. The cell death in C6 and U87 glioma cells could be inhibited by necroptosis inhibitor necrotatin-1, not by pan-caspase inhibitor z-VAD-fmk. Shikonin treated C6 glioma cells presented electron-lucent cytoplasm, loss of plasma membrane integrity and intact nuclear membrane in morphology. The increased ROS level caused by shikonin was attenuated by necrostatin-1 and blocking ROS by anti-oxidant NAC rescued shikonin-induced cell death in both C6 and U87 glioma cells. Moreover, the expressional level of RIP-1 was up-regulated by shikonin in a dose and time dependent manner as well, but NAC suppressed RIP-1 expression.ConclusionsWe demonstrated that the cell death caused by shikonin in C6 and U87 glioma cells was mainly via necroptosis. Moreover, not only RIP-1 pathway, but also oxidative stress participated in the activation of shikonin induced necroptosis.