Ovarian surface epithelium (OSE) forms a single layer of mostly cuboidal cells on surface of mammalian ovaries that is inherently exposed to cell stress evoked by tissue damage every ovulation and declines morphologically after menopause. Endoplasmic reticulum (ER) is a principal cell organelle involved in proteosynthesis, but also integrating various stress signals. ER stress evokes a conserved signaling pathway, the unfolded protein response (UPR), leading to cell death or adaptation to stress conditions. In this work, we document that mouse OSE suffers from ER stress during replicative senescence in vitro, develops abnormalities in ER and initiates UPR. Attenuation of ER stress in senescent OSE by tauroursodeoxycholic acid (TUDCA) reconditions ER architecture and leads to delayed onset of senescence. In summary, we show for the first time a mutual molecular link between ER stress response and replicative senescence leading to phenotypic changes of non-malignant ovarian surface epithelium.
- MeSH
- Down-Regulation drug effects MeSH
- Epithelium drug effects pathology ultrastructure MeSH
- Taurochenodeoxycholic Acid pharmacology MeSH
- RNA, Messenger genetics metabolism MeSH
- Mice MeSH
- Ovary pathology MeSH
- Cellular Senescence drug effects MeSH
- Endoplasmic Reticulum Stress drug effects MeSH
- Tunicamycin pharmacology MeSH
- Up-Regulation drug effects MeSH
- Telomere Shortening drug effects MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The midgut epithelia of the millipedes Polyxenus lagurus, Archispirostreptus gigas and Julus scandinavius were analyzed under light and transmission electron microscopies. In order to detect the proliferation of regenerative cells, labeling with BrdU and antibodies against phosphohistone H3 were employed. A tube-shaped midgut of three millipedes examined spreads along the entire length of the middle region of the body. The epithelium is composed of digestive, secretory and regenerative cells. The digestive cells are responsible for the accumulation of metals and the reserve material as well as the synthesis of substances, which are then secreted into the midgut lumen. The secretions are of three types - merocrine, apocrine and microapocrine. The oval or pear-like shaped secretory cells do not come into contact with the midgut lumen and represent the closed type of secretory cells. They possess many electron-dense granules (J. scandinavius) or electron-dense granules and electron-lucent vesicles (A. gigas, P. lagurus), which are accompanied by cisterns of the rough endoplasmic reticulum. The regenerative cells are distributed individually among the basal regions of the digestive cells. The proliferation and differentiation of regenerative cells into the digestive cells occurred in J. scandinavius and A. gigas, while these processes were not observed in P. lagurus. As a result of the mitotic division of regenerative cells, one of the newly formed cells fulfills the role of a regenerative cell, while the second one differentiates into a digestive cell. We concluded that regenerative cells play the role of unipotent midgut stem cells.
- MeSH
- Arthropods physiology ultrastructure MeSH
- Epithelium secretion ultrastructure MeSH
- Stem Cells physiology ultrastructure MeSH
- Digestive System secretion ultrastructure MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic MeSH
BACKGROUND: Gregarines represent a very diverse group of early emerging apicomplexans, parasitising numerous invertebrates and urochordates, and are considered of little practical significance. Recently, they have gained more attention since some analyses showed that cryptosporidia are more closely related to the gregarines than to coccidia. METHODOLOGY/PRINCIPAL FINDINGS: Using a combined microscopic approach, this study points out the spectacular strategy of Gregarina cuneata for attachment to host tissue and nutrient acquisition while parasitising the intestine of yellow mealworm larvae, and reveals the unusual dynamics of cellular interactions between the host epithelium and parasite feeding stages. Trophozoites of G. cuneata develop epicellularly, attached to the luminal side of the host epithelial cell by an epimerite exhibiting a high degree of morphological variability. The presence of contractile elements in the apical region of feeding stages indicates that trophozoite detachment from host tissue is an active process self-regulated by the parasite. A detailed discussion is provided on the possibility of reversible retraction and protraction of the eugregarine apical end, facilitating eventual reattachment to another host cell in better physiological conditions. The gamonts, found in contact with host tissue via a modified protomerite top, indicate further adaptation of parasite for nutrient acquisition via epicellular parasitism while keeping their host healthy. The presence of eugregarines in mealworm larvae even seems to increase the host growth rate and to reduce the death rate despite often heavy parasitisation. CONCLUSIONS/SIGNIFICANCE: Improved knowledge about the formation of host-parasite interactions in deep-branching apicomplexans, including gregarines, would offer significant insights into the fascinating biology and evolutionary strategy of Apicomplexa. Gregarines exhibit an enormous diversity in cell architecture and dimensions, depending on their parasitic strategy and the surrounding environment. They seem to be a perfect example of a coevolution between a group of parasites and their hosts.
- MeSH
- Actins metabolism MeSH
- Apicomplexa cytology physiology ultrastructure MeSH
- Epithelium metabolism parasitology ultrastructure MeSH
- Epithelial Cells metabolism parasitology ultrastructure MeSH
- Adaptation, Physiological * MeSH
- Host-Pathogen Interactions MeSH
- Myosins metabolism MeSH
- Symbiosis * MeSH
- Tenebrio parasitology MeSH
- Protein Transport MeSH
- Protein Binding MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Eubranchipus grubii (Crustacea, Branchiopoda, Anostraca) is an omnivorous filter feeder whose life span lasts no more than 12 weeks. Adult males and females of E. grubii were used for ultrastructural studies of the midgut epithelium and an analysis of autophagy. The midgut epithelium is formed by columnar digestive cells and no regenerative cells were observed. A distinct regionalization in the distribution of organelles appears - basal, perinuclear and apical regions were distinguished. No differences in the ultrastructure of digestive cells were observed between males and females. Autophagic disintegration of organelles occurs throughout the midgut epithelium. Degenerated organelles accumulate in the neighborhood of Golgi complexes, and these complexes presumably take part in phagophore and autophagosome formation. In some cases, the phagophore also surrounds small autophagosomes, which had appeared earlier. Fusion of autophagosomes and lysosomes was not observed, but lysosomes are enclosed during autophagosome formation. Autophagosomes and autolysosomes are discharged into the midgut lumen due to apocrine secretion. Autophagy plays a role in cell survival by protecting the cell from cell death.
- MeSH
- Anostraca physiology ultrastructure MeSH
- Autophagy MeSH
- Epithelium physiopathology ultrastructure MeSH
- Phagosomes ultrastructure MeSH
- Gastrointestinal Tract physiology ultrastructure MeSH
- Microscopy, Electron, Transmission MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic MeSH
- MeSH
- Microscopy, Electron MeSH
- Endometrium anatomy & histology drug effects ultrastructure MeSH
- Epithelium anatomy & histology drug effects ultrastructure MeSH
- Fertilization drug effects drug effects MeSH
- Financing, Organized MeSH
- Gonadotropins MeSH
- Phosphodiesterase Inhibitors MeSH
- Ovulation MeSH
- Progesterone MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Comparative Study MeSH
Eugregarines represent a diverse group of Apicomplexa parasitising numerous invertebrates. Their sporozoites generally develop into epicellular trophozoites attached to the host epithelium by a specialised attachment organelle known as an epimerite. They are considered peculiar protists due to their unique cell architecture and dimensions as well as their attachment strategy which is similar to that of cryptosporidia. Using electron and fluorescence microscopy, the fine structure of the epimerite with associated structures and the mechanism of trophozoite detachment from the host epithelium were studied in Gregarina polymorpha parasitising the intestine of Tenebrio molitor larvae. The epimerite appears to be a very dynamic structure whose shape dramatically changes depending on whether or not it is embedded into the host epithelium. The trophozoite's most fragile zone is the area below the membrane fusion site at the epimerite base. The epimerite plasma membrane forms basal radial ribs which are involved in increasing its surface and strengthening the epimerite-host cell junction. FITC-phalloidin labelling demonstrated the presence of filamentous actin in trophozoites along with its accumulation at the epimerite base and in the apical end of the protomerite, as well as a patch accumulation of filamentous actin in the protomerite of maturing and mature trophozoites. Indirect immunofluorescence revealed the presence of myosin in the cortical zone of the epimerite and in the membrane fusion site area. The data obtained strongly suggest that these structures could facilitate the detachment of a mature trophozoite from the host epithelium. Supported by data presented herein and our previous observations, we propose a new hypothesis on the mechanism of trophozoite detachment from the host epithelium based on epimerite retraction into the protomerite. This is contrary to the commonly accepted hypothesis describing gradual epimerite constriction and subsequent separation facilitated by contractility of the membrane fusion site (osmiophilic ring).
- MeSH
- Actins metabolism MeSH
- Apicomplexa physiology ultrastructure MeSH
- Cell Membrane metabolism ultrastructure MeSH
- Epithelium parasitology ultrastructure MeSH
- Phalloidine MeSH
- Fluorescein-5-isothiocyanate MeSH
- Fluorescent Dyes MeSH
- Membrane Fusion physiology MeSH
- Host-Parasite Interactions physiology MeSH
- Larva parasitology MeSH
- Microscopy, Electron, Scanning MeSH
- Organelles metabolism ultrastructure MeSH
- Tenebrio parasitology MeSH
- Tissue Distribution MeSH
- Digestive System parasitology MeSH
- Trophozoites physiology ultrastructure MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The aim of this work was to investigate the early development of the deciduous dentition and oral vestibule in the human embryonic lower jaw. Histological sections and three-dimensional reconstructions from prenatal weeks 6-9 were used. A continuous anlage for the oral vestibule did not exist in the mandible. In contrast to the upper jaw, where we previously observed that the dental and vestibular epithelia developed separately, two dento-vestibular bulges differentiated in the incisor region of the mandible. The lingual parts of each bulge were found to give rise to the respective central and lateral incisors, whereas the labial parts differentiated into the vestibular epithelium. In the canine and molar areas, the dental and vestibular epithelia originated separately. Later, the segments of the vestibular epithelium fused into the labial vestibular ridge, giving rise to the lower oral vestibule in the lip region. In the cheek region, the oral vestibule was found to originate in the mucosal inflection between the developing jaw and the cheek. A similar heterogeneous developmental base for the oral vestibule was also observed in the upper jaw. There is thus no general scheme for the early development of the dental and vestibular epithelia that applies to both the upper and lower jaws, and to both their anterior and posterior regions.
- MeSH
- Embryonic Development physiology MeSH
- Epithelium embryology ultrastructure MeSH
- Financing, Organized MeSH
- Humans MeSH
- Mandible embryology ultrastructure MeSH
- Maxilla embryology ultrastructure MeSH
- Pregnancy MeSH
- Mouth embryology ultrastructure MeSH
- Imaging, Three-Dimensional methods MeSH
- Tooth, Deciduous MeSH
- Tooth embryology ultrastructure MeSH
- Check Tag
- Humans MeSH
- Pregnancy MeSH
- Female MeSH
- Publication type
- Comparative Study MeSH
Morphological differentiation of the intestinal epithelium in the laboratory rat occurs between the 16th and 21st day of prenatal development. The pseudostratified epithelium is rebuilt into simple epithelium of the future lining. A characteristic sign of this rebuilding is formation of primitive folds, villi and intraepithelial vacuoles corresponding in submicroscopic picture with a secondary luminization. On the tips of folds and villi groups of cells released from the epithelium are observed. In these cells expression of activated caspase-3 confirms the presence of apoptosis in the process of cell death during epithelium rebuilding.
