Showing papers on "Ultrastructure published in 2016"
TL;DR: It is stated that autophagy plays a role of the survival factor in the endodermal region of the digestive system in the freshwater shrimp Neocaridina heteropoda because degenerating organelles, mainly mitochondria were neutralized and eventually, the activation of cell death was prevented in the entire epithelium due to Autophagy.
Abstract: The endodermal region of the digestive system in the freshwater shrimp Neocaridina heteropoda (Crustacea, Malacostraca) consists of a tube-shaped intestine and large hepatopancreas, which is formed by numerous blind-ended tubules. The precise structure and ultrastructure of these regions were presented in our previous studies, while here we focused on the cell death processes and their effect on the functioning of the midgut. We used transmission electron microscopy, light and confocal microscopes to describe and detect cell death, while a quantitative assessment of cells with depolarized mitochondria helped us to establish whether there is the relationship between cell death and the inactivation of mitochondria. Three types of the cell death were observed in the intestine and hepatopancreas–apoptosis, necrosis and autophagy. No differences were observed in the course of these processes in males and females and or in the intestine and hepatopancreas of the shrimp that were examined. Our studies revealed that apoptosis, necrosis and autophagy only involves the fully developed cells of the midgut epithelium that have contact with the midgut lumen–D-cells in the intestine and B- and F-cells in hepatopancreas, while E-cells (midgut stem cells) did not die. A distinct correlation between the accumulation of E-cells and the activation of apoptosis was detected in the anterior region of the intestine, while necrosis was an accidental process. Degenerating organelles, mainly mitochondria were neutralized and eventually, the activation of cell death was prevented in the entire epithelium due to autophagy. Therefore, we state that autophagy plays a role of the survival factor.
31 citations
TL;DR: The aging process showed changes in the collagen fibrils, with a predominance of type III fibers in the elderly group, in addition to a decrease in the amount of the fibrocartilage cells, fewer and shorter cytoplasmic processes and a decreased synthetic capacity due to degradation of the organelles involved in synthesis.
Abstract: Tendons are transition tissues that transfer the contractile forces generated by the muscles to the bones, allowing movement. The region where the tendon attaches to the bone is called bone-tendon junction or enthesis and may be classified as fibrous or fibrocartilaginous. This study aims to analyze the collagen fibers and the cells present in the bone-tendon junction using light microscopy and ultrastructural techniques as scanning electron microscopy and transmission electron microscopy. Forty male Wistar rats were used in the experiment, being 20 adult rats at 4 months-old and 20 elderly rats at 20 months-old. The hind limbs of the rats were removed, dissected and prepared to light microscopy, transmission electron microscopy and scanning electron microscopy. The aging process showed changes in the collagen fibrils, with a predominance of type III fibers in the elderly group, in addition to a decrease in the amount of the fibrocartilage cells, fewer and shorter cytoplasmic processes and a decreased synthetic capacity due to degradation of the organelles involved in synthesis.
29 citations
TL;DR: The aim of the study was to describe the ultrastructure of the gut epithelium in Acheta domesticus after exposure to different concentrations of ND, and a positive relationship between the ND concentration in food and the degree of damage to the structure of epithelial cells was observed.
29 citations
TL;DR: This first study of its kind used 3D sSAXS to investigate the ultrastructural organization of 22 vertebral trabeculae of different alignment, types and sizes, obtained from 4 subjects of different ages and found that ultrastructure organization is similar for all investigated trabECulae independent of their particular characteristics.
Abstract: Although the organization of bone ultrastructure, i.e. the orientation and arrangement of the mineralized collagen fibrils, has been in the focus of research for many years for cortical bone, and many models on the osteonal arrangement have been proposed, limited attention has been paid to trabecular bone ultrastructure. This is surprising because trabeculae play a crucial role for the mechanical strength of several bone sites, including the vertebrae and the femoral head. On this account, we first validated a recently developed method (3D sSAXS or 3D scanning small-angle X-ray scattering) for investigating bone ultrastructure in a quantitative and spatially resolved way, using conventional linearly polarized light microscopy as a gold standard. While both methods are used to analyze thin tissue sections, in contrast to polarized light microscopy, 3D sSAXS has the important advantage that it provides 3D information on the orientation and arrangement of bone ultrastructure. In this first study of its kind, we used 3D sSAXS to investigate the ultrastructural organization of 22 vertebral trabeculae of different alignment, types and sizes, obtained from 4 subjects of different ages. Maps of ultrastructure orientation and arrangement of the trabeculae were retrieved by stacking information from consecutive 20-μm-thick bone sections. The organization of the ultrastructure was analyzed in relation to trabecular microarchitecture obtained from computed tomography and to relevant parameters such as distance to trabecular surface, local curvature or local bone mineralization. We found that (i) ultrastructure organization is similar for all investigated trabeculae independent of their particular characteristics, (ii) bone ultrastructure exhibiting a high degree of orientation was arranged in domains, (iii) highly oriented ultrastructural areas were located closer to the bone surface, (iv) the ultrastructure of the human trabecular bone specimens followed the microarchitecture, being oriented mostly parallel to bone surface, and (v) local surface curvature seems to have an effect on the ultrastructure organization. Further studies that investigate bone ultrastructure orientation and arrangement are needed in order to understand its organization and consequently its relation to bone biology and mechanics.
24 citations
TL;DR: The ultrastructure analysis revealed many sever alterations due to the action of AgNPs, such us shortening and condensation of hyphae, ultrastructural reorganisation, cell plasmolysis, increased vacuolisation, numerous membranous structures, collapsed cytoplasm and accumulation of lipid material.
Abstract: Silver nanoparticles (AgNPs) are widely used in all branches of industry. However, their mechanisms of action towards moulds have not been studied yet. Thus we conducted this study in which we have used laser desorption/ionization time-of-flight mass spectrometry (LDI-ToF-MS) analysis to determine metabolomic changes, and microscopic analysis (transmission electron microscopy, fluorescent microscopy) to observe changes in mould cells. The AgNP treatment caused the downregulation of 162 (15 ppm) and 284 (62 ppm), and 19 (15 ppm) and 29 (62 ppm) metabolites of Aspergillus niger and Penicillium chrysogenum, respectively. All influenced features were below m/z 600 (mass-to-charge ratio). We have observed silver ions and their clusters (Ag, Ag2, and Ag3) accumulated in the mould mycelium. As well as, mono-silver ion adducts with nucleotide derivatives (Coenzyme A), amino acids (phenylglycine), peptides (LeuSerAlaLeuGlu) and lipids (fatty acids, diacylglycerophosphoglycerols, monoglicerides and glycerophospholipids). The ultrastructure analysis revealed many sever alterations due to the action of AgNPs, such us shortening and condensation of hyphae, ultrastructural reorganisation, cell plasmolysis, increased vacuolisation, numerous membranous structures, collapsed cytoplasm, accumulation of lipid material, condensed mitochondria, disintegration of organelles, nuclear deformation, condensation and fragmentation of chromatin, creation of apoptotic bodies, as well as a new inside cell wall in P. chrysogenum.
19 citations
TL;DR: This study elucidate how DDR1 modulates collagen fibril ultrastructure in vivo, which may have important consequences in the functional role(s) of the underlying ECM.
Abstract: The quantity and quality of collagen fibrils in the extracellular matrix (ECM) have a pivotal role in dictating biological processes. Several collagen-binding proteins (CBPs) are known to modulate collagen deposition and fibril diameter. However, limited studies exist on alterations in the fibril ultrastructure by CBPs. In this study, we elucidate how the collagen receptor, discoidin domain receptor 1 (DDR1) regulates the collagen content and ultrastructure in the adventitia of DDR1 knock-out (KO) mice. DDR1 KO mice exhibit increased collagen deposition as observed using Masson's trichrome. Collagen ultrastructure was evaluated in situ using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Although the mean fibril diameter was not significantly different, DDR1 KO mice had a higher percentage of fibrils with larger diameter compared with their wild-type littermates. No significant differences were observed in the length of D-periods. In addition, collagen fibrils from DDR1 KO mice exhibited a small, but statistically significant, increase in the depth of the fibril D-periods. Consistent with these observations, a reduction in the depth of D-periods was observed in collagen fibrils reconstituted with recombinant DDR1-Fc. Our results elucidate how DDR1 modulates collagen fibril ultrastructure in vivo, which may have important consequences in the functional role(s) of the underlying ECM.
18 citations
TL;DR: It is suggested that Hsp27 could directly impact the organization of muscle cytoskeleton at the molecular and ultrastructural levels.
Abstract: Even though abundance of Hsp27 is the highest in skeletal muscle, the relationships between the expression of HspB1 (encoding Hsp27) and muscle characteristics are not fully understood. In this study, we have analysed the effect of Hsp27 inactivation on mouse development and phenotype. We generated a mouse strain devoid of Hsp27 protein by homologous recombination of the HspB1 gene. The HspB1-/- mouse was viable and fertile, showing neither apparent morphological nor anatomical alterations. We detected a gender dimorphism with marked effects in males, a lower body weight (P < 0.05) with no obvious changes in the growth rate, and a lower plasma lipids profile (cholesterol, HDL and triglycerides, 0.001 < P< 0.05). The muscle structure of the animals was examined by optical microscopy and transmission electron microscopy. Not any differences in the characteristics of muscle fibres (contractile and metabolic type, shape, perimeter, cross-sectional area) were detected except a trend for a higher proportion of small fibres. Different myosin heavy chains electrophoretic profiles were observed in the HspB1-/- mouse especially the presence of an additional isoform. Electron microscopy revealed ultrastructural abnormalities in the myofibrillar structure of the HspB1-/- mouse mutant mice (e.g. destructured myofibrils and higher gaps between myofibrils) especially in the m. Soleus. Combined with our previous data, these findings suggest that Hsp27 could directly impact the organization of muscle cytoskeleton at the molecular and ultrastructural levels.
17 citations
01 Jan 2016
TL;DR: In this paper, the topography, external structure, and ultrastructure of exocrine dermal glands are described in one of the two adult male forms of the ascidicolous marine copepod Pachypygus gibber.
Abstract: The topography, external structure, and ultrastructure of hitherto unknown exocrine dermal glands are described in one of the two adult male forms of the ascidicolous marine copepod Pachypygus gibber. The glands are located in the pleural lateroventral zone of the cephalosome. They are composed of three cells: secretory cell, intermediary cell, and canal cell. The secretory cell undergoes transformations involving four successive phases. The final phase leads to an autolysis of the cellular components with emptying of the cell content. An interesting feature is the spatial association of the glandular cells and their pores with sensory cells and their pores, the latter being considered as a chemoreceptor organ. The secretion is thereby in direct contact with dendritic ends devoid of cuticular cover, which protrude outside the copepod via the sensory pores. The various characteristics of this "sensory-glandular" complex, present exclusively in the atypical male (which has an additional free planktonic phase as an adult), lead to the hypothesis of a functional cooperation between the glandular apparatus and the sensory organ.
16 citations
TL;DR: A close relationship is demonstrated between changes in cell membrane ultrastructure and cytoskeletal alterations (F-actin) in propofol-treated HeLa cells, which can be directly reflected by changes in cellular morphology, as assessed by AFM.
Abstract: Background: Although significant advances have been made toward understanding the molecular mechanisms underlying the effect of propofol on tumor cell metastasis, less is known regarding how cell membrane and cytoskeletal ultrastructure are affected in this process. Here, we investigated the relationship between cell morphology and cell size, which are features mainly defined by the cytoskeleton. Methods: To confirm the effects of propofol on the migratory ability of human cervical carcinoma cells, cell migration and invasion were examined through scratch wound healing and transwell membrane assays. Furthermore, HeLa cells cultivated with different concentrations of propofol were examined by confocal microscopy and atomic force microscopy (AFM), and the mean optical density and migration ability of these cells were also assessed. In addition, cell membrane morphology was inspected using AFM. Results: The results of the wound healing and transwell membrane assays indicated that propofol decreases the migratory ability of cervical carcinoma cells compared to control cells. A comparative analysis of the test results revealed that short-term (3 h) exposure to propofol induced marked changes in cell membrane microstructure and in the cytoskeleton in a dose-dependent manner. These morphological changes in the cell membrane were accompanied by cytoskeleton (F-actin) derangement. The present findings demonstrate a close relationship between changes in cell membrane ultrastructure and cytoskeletal alterations (F-actin) in propofol-treated HeLa cells. AFM scanning analysis showed that cell membrane ultrastructure was significantly changed, including a clear reduction in membrane roughness. Conclusion: The influence of propofol on the HeLa cell cytoskeleton can be directly reflected by changes in cellular morphology, as assessed by AFM. Moreover, the use of AFM is a good method for investigating propofol-mediated changes within cytoskeletal ultrastructure.
15 citations
TL;DR: In this paper, the effects of SPS on cellular organelles of the hippocampal neurons remain unknown; however, these changes have been involved in SPS-induced abnormal hippocampal function.
12 citations
TL;DR: Sperm analysis of these shrimps reflects their phylogenetic history and that such analysis is very useful for taxonomic studies, and it is possible to detect different groups within the genus based on the presence of at least two distinct morphological patterns of ultrastructure.
Abstract: We describe the sperm ultrastructure of two sympatric rock shrimps, Sicyonia dorsalis and Sicyonia typica, and compare them in a molecular context to provide new insight into the sperm morphology of the Sicyoniidae. To accomplish this, the vasa deferentia of males of both species were fixed and prepared for transmission electron microscopy and light microscopy cytochemistry. Sperm of S. typica exhibit an oval main body and a short subacrosomal complex region with convoluted membrane pouches, a crystalline lattice and a well-developed large granule anterior to the spike, as previously described for Sicyonia carinata. In contrast, the ultrastructure of S. dorsalis sperm features an elongated complex subacrosomal region above the main body and a flat nucleus, and small cytoplasmic membrane vesicles are not present. Although S. dorsalis sperm are similar to those of Sicyonia ingentis, the spike of S. dorsalis is shorter than S. ingentis. A phylogenetic tree was built by Bayesian inference based on 19 sequences of 16S rDNA of some representatives of the genus. Our findings show that sperm analysis of these shrimps reflects their phylogenetic history and that such analysis is very useful for taxonomic studies. Species with corresponding sperm ultrastructure are in the same clade of the proposed phylogeny. Moreover, it is possible to detect different groups within the genus based on the presence of at least two distinct morphological patterns of ultrastructure in the spermatozoa of Sicyonia.
TL;DR: Results suggest angiogenesis occurs in early developing goat corpora lutea CL and programmed cell death occurred in the late stage of CL assessment in the present study.
01 Jan 2016
TL;DR: Microscopic examinations have confirmed the fungicidal and eliciting properties of chitosan and formation of structural barriers by the host, mainly through inter- and intracellular synthesis of phenolic-lignin-like material that stops fungal invasion.
Abstract: Summary A number of studies have confirmed the in vitro fungicidal effect of chitosan on various phytopathogenic fungal families including among others, Mucoraceae, Pleosporaceae, and Glomerellaceae. Investigations of the morphology and ultrastructure of the chitosan-treated fungi in in vitro studies and during the plant-pathogen interaction of various pathosystems have been carried out by using conventional optical/light microscopy and with other advanced instruments including SEM, TEM, and confocal microscopy. The electrostatic interaction between chitosan and the microorganism is noted by dramatic alterations observed from the damaged structure of the cell wall and plasma membrane. The integrity of organelles including vacuoles was seriously affected, leading in some cases to lysis of the fungal cell. During the host-pathogen interaction, formation of structural barriers by the host, mainly through inter- and intracellular synthesis of phenolic-lignin-like material that stops fungal invasion, was also observed. Fungal growth was not beyond the outer cortical area of the infected tissues, while damage on fungi was similar to those observed in in vitro studies. Microscopic examinations have confirmed the fungicidal and eliciting properties of chitosan.
TL;DR: The ontogeny and ultrastructure of the pollen grain and related sporophytic structures of H. dulcis are described with special attention to tapetum cytology in Hovenia dULcis.
Abstract: Despite that there is some literature on pollen morphology of Rhamnaceae, studies addressing general aspects of the microsporogenesis, microgametogenesis, and anther development are rare. The aim of this paper is to describe the ultrastructure of pollen grain ontogeny with special attention to tapetum cytology in Hovenia dulcis. Anthers at different stages of development were processed for transmission and scanning electron microscopy, bright-field microscopy, and fluorescence microscopy. Different histochemical reactions were carried out. The ultrastructural changes observed during the development of the tapetal cells and pollen grains are described. Large vesicles containing carbohydrates occur in the tapetal cell cytoplasm during the early stages of pollen development. Its origin and composition are described and discussed. This is the first report on the ontogeny and ultrastructure of the pollen grain and related sporophytic structures of H. dulcis.
TL;DR: The ultrastructure of eggs of T. asiatica is shown for the first time by means of SEM and TEM analyses, and the presence of two types of small vesicles is described herein, possibly corresponding to exosomes and ectosomes because of their shape and size, which could participate in the host/parasite intercellular communication.
Abstract: Humans are definitive hosts of three species of the Taenia genus, namely Taenia solium, Taenia saginata and Taenia asiatica. The relative novelty of the latter explains the lack of knowledge concerning certain relevant aspects related to this parasite, such as its definite geographical distribution and whether its eggs can infect humans or not. So far, only the eggs of T. solium are known to be infective for humans, producing cysticercosis. Although eggs contain the infective stage, the oncosphere, there is a lack of research on the ultrastructure of eggs of human taeniids. We show, for the first time, the ultrastructure of eggs of T. asiatica by means of SEM and TEM analyses. We detected all the envelopes, namely the egg shell, vitelline layer, outer embryophoric membrane, embryophore, granular layer, basal membrane, oncospheral membrane and oncospheral tegument. Hooks surrounded by myofibrils and glycogen-like particles, the two types of secretory granules of the penetration glands, as well as several nuclei and mitochondria were also revealed in the oncospheres. In addition to the already known structures in eggs from other Taenia species, the presence of two types of small vesicles is described herein, possibly corresponding to exosomes and ectosomes because of their shape and size, which could participate in the host/parasite intercellular communication.
TL;DR: Malnutrition produces subcellular alterations in vulnerable hippocampal pyramidal cells, and these alterations may provide an explanation for the previously reported deficient performance of malnourished animals in a spatial memory task in which aging and malnutrition were shown to impede the maintenance of long-term memory.
Abstract: Objectives: Malnourishment (M) produces permanent alterations during the development of the CNS and might modify the aging process. In pyramidal neurons (PN) of the hippocampus, which are associated with learning and memory performance, few studies have focused on changes at the subcellular level under chronic malnutrition (ChM) in young (Y, 2 months old) and aged (A, 22 months old) rats. The present work evaluated the extent to which ChM disrupts organelles in PN of the dorsal hippocampus CA1 as compared to controls (C).Methods: Ultrastructural analysis was performed at 8000× and 20 000× magnification: Nucleus eccentricity and somatic, cytoplasmic, and nuclear areas were measured; and in the PN perikaryon, density indices (number of organelles/cytoplasmic area) of Golgi membrane systems (GMS, normal, and swollen), mitochondria (normal and abnormal), and vacuolated organelles (lysosomes, lipofuscin granules, and multivesicular bodies (MVB)) were determined.Results: The density of abnormal mitochondria, ...
TL;DR: A TEM method that allows the evaluation of organelles using pancreatic tissue that was previously liquid nitrogen snap-frozen and stored long-term at −80°C is developed, suitable for the quantitative assessment of mitochondria, rough endoplasmic reticulum (RER), and Golgi structures, as well as organelle originating from autophagy signaling.
Abstract: For many years it has been believed that ultrastructural analysis by transmission electron microscopy (TEM) is not possible using frozen tissues We have developed a TEM method that allows the evaluation of organelles using pancreatic tissue that was previously liquid nitrogen snap-frozen and stored long-term at -80°C This method is suitable for the quantitative assessment of mitochondria, rough endoplasmic reticulum (RER), and Golgi structures, as well as organelles originating from autophagy signaling Frozen pancreatic tissue exhibited no signs of freezing- or storage-related damage and was undistinguishable from fresh material subjected to standard glutaraldehyde fixation Since pancreatic tissue is the most delicate tissue to work with due to the high expression of digestive enzymes, our method is also suitable for other tissue types such as liver Thus, by applying proper tissue freezing and fixation techniques, retrospective TEM analysis can be performed on mammalian tissues in a time- and cost-saving manner
TL;DR: This work isolated mature spermatozoa from White Pekin duck by non‐invasive methods and performed several immunostaining analysis as well as cytochemical analysis using electron and light microscopes, and proposes that these ultrastructural and molecular parameters can be used as species‐specific features.
Abstract: The morphology, ultrastructure, and functions of mature avian spermatozoa have been of immense commercial and scientific interest for several reasons. This is mainly important in case of birds in poultry production, conservation, and in the use of sperm morphometry as phylogenetic evidence. Avian spermatozoa share complex or no correlation of sperm morphometry with respect to testis and/or body size as described before. In this work, we have isolated mature spermatozoa from White Pekin duck (Anas platyrhynchos) by non-invasive methods and performed several immunostaining analysis as well as cytochemical analysis using electron and light microscopes. Here, we report the presence of different post-translationally modified tubulin such as tyrosinated-, detyrosinated-, acetylated-, polyglutamylated-, and glycylated-tubulin in specific regions of the mature spermatozoa. By using field-emission scanning electron microscope, we confirm the presence of acrosome-like structure at the tip of the sperm head. However, this structure remains non-reactive to common lectins such as Peanut Agglutinin (PNA) and cholesterol-sensitive dyes such as Filipin. We report that this acrosomal structure is primarily made of lipid-based structures and is resistant to 0.1% Triton X100. Confocal microscopy and super resolution structured illumination microscopy study indicates that the nucleus is bifurcated at the tip region. By using specific markers, we report that the perforatorium structure present at the tip of the spermatozoa head contains specialized organelles that is similar to atypical mitochondria. We propose that these ultrastructural and molecular parameters can be used as species-specific features. The bifurcated nucleus and presence of atypical mitochondria within this structure may be relevant for the complex mitochondrial inheritance and mitochondrial heteroplasmy observed in case of avian population.
TL;DR: The results largely corroborate the basic observations and interpretations of previous TEM studies on other neodermatans and provide insight into a powerful suite of cryo-techniques that can enhance the work with these challenging subjects.
Abstract: Ultrastructure of eggs of the cestode Gyrocotyle urna Grube and Wagener 1852 with fully formed shells and early embryonic stages is described for the first time. Multiple techniques used included cryo-methods of high-pressure freezing with freeze substitution combined with field emission scanning electron microscopy and transmission electron microscopy (TEM). After 20 days of in vitro maturation, eggs are composed, from the exterior to the interior, of a thick egg shell of vitelline origin, an early embryonic envelope, a ring of numerous large vitellocytes, and a group of differentiating blastomeres situated in the center, forming the early presumptive larva. The thick resistant egg shell is similar to that reported from other polylecithal neodermatan flatworms. The embryonic envelope is poorly formed at this stage and not yet divided into inner and outer envelopes as occurs in all neodermatans described to date. Vitellocytes are separate, not forming a syncytium, and are filled with diverse vitelline materials as well as lipid droplets and associated endomembrane components having ultrastructure consistent with macroautophagy systems seen among many animals in apoptotic or autophagic cells. These results largely corroborate the basic observations and interpretations of previous TEM studies on other neodermatans and provide insight into a powerful suite of cryo-techniques that can enhance our work with these challenging subjects.
TL;DR: It is demonstrated that there are great variations in ultrastructure and chemistry of cell walls within a single growth ring of English oak xylem.
Abstract: Although there is considerable information on anatomy and gross chemistry of oak wood, little is known on the ultrastructure and chemistry at the individual cell wall level. In particular, differences in ultrastructure and chemistry within the same cell type between earlywood (EW) and latewood (LW) are poorly understood. This study investigated the ultrastructure and chemistry of (vasicentric) tracheids, vessels, (libriform) fibers and axial/ray parenchyma cells of English oak xylem (Quercus robur L.) using light-, fluorescence- and transmission electron microscopy combined with histo/cytochemistry and immunohisto/ cytochemistry. EW tracheids showed several differences from LW tracheids including thinner cell walls, wider middle lamella cell corner (MLcc) regions and lesser amounts of mannan epitopes. Fibers showed thicker cell walls and higher amounts of mannan epitopes than tracheids. EW vessels were rich in guaiacyl (G) lignin with a characteristic non-layered cell wall organization (absence of S1–3 layers), whereas LW vessels were rich in syringyl (S) lignin with a three layered cell wall structure (S1–3 layers). Formation of a highly lignified and wide protective layer (PL) inside axial/ray parenchyma cells was detected only in EW. Distribution of mannan epitopes varied greatly between cell types and between EW and LW, whereas distribution of xylan epitopes was almost identical in all cell types within a growth ring. Together, this study demonstrates that there are great variations in ultrastructure and chemistry of cell walls within a single growth ring of English oak xylem.
TL;DR: The ultrastructure of the female gonad of the marine polyclad Echinoplana celerrima was investigated using both light and electron microscopy to identify some multivesicular bodies (MVBs) and their function.
Abstract: Here, the ultrastructure of the female gonad of the marine polyclad Echinoplana celerrima was investigated using both light and electron microscopy. The female gonads are dispersed in the dorsal parenchyma between the digestive ramifications. Each ovary is separated from adjacent tissues by a homogeneous basal lamina and is characterized by the presence of a germinative zone, growing oocytes at the previtellogenic stage, and at the vitellogenic stage. The germinative zone is located at the dorsal part of the gonad and is characterized by the presence of undifferentiated young germ cells or oogonia having a large nucleus with a well-shaped nucleolus. Growing oocytes at the previtellogenic stage are characterized by the production and accumulation of eggshell granules. Indeed, the cytoplasm is gradually packed with cytoplasmic organelles and electron-dense inclusions that coalesce to form eggshell granules. When maturing, the latter become formed in their center by an electron-dense core surrounded by very electron-dense areas of variable shape. During the vitellogenesis stage, the oocytes undergo a notable increase in the cytoplasmic volume due to the accumulation of specific organelles such as free ribosomes and endoplasmic reticulum. These specific cytoplasmic organelles are probably involved in the production of vesicles containing a medium-dense and granular material. Repeated coalescence of these vesicles gives rise to the yolk globules. At this stage, the cytoplasm also displays some multivesicular bodies (MVBs). The origin of these MVBs and their function is discussed.
TL;DR: A new, previously unknown type of crustacean glands is described.
Abstract: The anatomy and ultrastructure of “amphipod silk” glands in Ampithoe rubricata Montagu 1818 (Ampithoidae) have been studied. The morphology and ultrastructure of the glands in pereopods 3 and 4 have been examined in semithin and ultrathin sections using light and transmission electron microscopy. The glands of two types producing secretions different in their chemical compositions are observed in these pereopods. The ducts of the glands of both types lead to a common reservoir in the dactylus. Each gland comprises several secretory cells and one duct cell. The structure earlier regarded as the chitin wall of the duct is the cytoplasm of the duct cell; the presence of this cell in the studied glands is demonstrated for the first time. The secretory cells contain one or two nuclei and form rows along each duct cell. A new, previously unknown type of crustacean glands is described.
TL;DR: It was shown that the ultrastructure of agranulocytes and rodlet cells in the studied species is similar to that of cells in freshwater bony fish.
Abstract: The ultrastructure of cells that form mesonephros tissues in eight species of bony fish of the Black Sea, Gaidropsarus mediterraneus (L.), Lisa aurata (Risso), Trachurus mediterraneus (Staindachner), Diplodus annularis (L.), Spicara flexuosa (Rafinesque), Gobius niger jozo L., Mullus barbatus ponticus (Essipov) and Scorpaena porcus (L.), was studied. It was shown that the ultrastructure of agranulocytes and rodlet cells in the studied species is similar to that of cells in freshwater bony fish. The differences were observed in the number of ionocyte mitochondria, in the vesicle ultrastructure in the cells with radial vesicle array, and in the ultrastructure of the specific secondary granules of neutrophils and eosinophils.
TL;DR: High-passage IVF-pESCs showed irregularly shaped colonies, pyknosis and numerous lysosomes associated with autophagic vacuoles showing signs of apoptosis, confirming that the ultrastructural characteristics of pESCs differ depending on their origin.
Abstract: The ultrastructure of porcine putative embryonic stem cells and porcine fetal fibroblasts (PFFs) was analyzed by transmission electron microscopy. The aim of this study was to compare the features of organelles in in vitro fertilization (IVF) derived porcine embryonic stem cells (IVF-pESCs) and somatic cell nuclear transfer (SCNT) derived pESCs (SCNT-pESCs). Also, the features of organelles in high-passage IVF-pESCs were compared with those in low-passage cells. The ultrastructure of PFFs showed rare microvilli on the cell surfaces, polygonal or irregular nuclei with one to two reticular-shaped nucleoli and euchromatin, low cytoplasm-to-nucleus ratios, rare ribosomes, rare rough endoplasmic reticulum, elongated mitochondria, rich lysosomes and rich phagocytic vacuoles. IVF-pESCs showed rare microvilli on the cell surfaces, round or irregular nuclei with one to two reticular-shaped nucleoli and euchromatin, low cytoplasm-to-nucleus ratios, rich ribosomes, long stacks of rough endoplasmic reticulum, elongated mitochondria, rare lysosomes and rare autophagic vacuoles. By contrast, SCNT-pESCs showed rich microvilli with various lengths and frequencies on the cell surfaces, polygonal nuclei with one reticular shaped nucleoli and heterochromatin, high cytoplasm-to-nucleus ratios, rare ribosomes, rare rough endoplasmic reticulum, round mitochondria, rich lysosomes and rich phagocytic vacuoles with clear intercellular junctions. Furthermore, high-passage IVF-pESCs showed irregularly shaped colonies, pyknosis and numerous lysosomes associated with autophagic vacuoles showing signs of apoptosis. In conclusion, this study confirms that the ultrastructural characteristics of pESCs differ depending on their origin. These ultrastructural characteristics might be useful in biomedical research using pESCs, leading to new insights regarding regenerative medicine and tissue repair.
TL;DR: The spermatozoa of the two Gyraulus species are compared with those of other Hygrophila and the possible importance of sperm morphology for the taxonomic status of G. (A.) crista is discussed.
Abstract: Sperm morphology offers a rich source of potentially informative characters for gastropod taxonomy and in this study it was used to provide additional information for Gyraulus (Armiger) crista (Linnaeus, 1758), whose taxonomic position within the Planorbidae Rafinesque, 1815 remains uncertain. Sperm morphology in G. (A.) crista and G. (Gyraulus) albus (Muller, 1774), the type species of the genus, was examined using light microscopy, scanning electron microscopy and transmission electron microscopy. The ultrastructure of spermatozoa in the two species was found to conform to the general pattern characteristic of the Hygrophila Ferussac, 1822: the spermatozoa had an anterior head containing an acrosomal complex (apical vesicle and acrosomal pedestal) and cone-shaped nucleus, followed by a very long midpiece with glycogen spirals, and then by a glycogen piece and tail. Although the spermatozoa of the two species shared some common features (one nuclear keel and four glycogen spirals), they differed ...
TL;DR: Cadmium exposure for 40 days induced dose-dependent microstructure and ultrastructure alterations in pallium of immature mice and the most obvious alterations were in the high dose group.
Abstract: The aim of this study was to investigate microstructure and ultrastructure alterations in the pallium of immature mice exposed to cadmium. Forty immature mice were randomly divided into control, 1/100 LD50 (1.87 mg/kg, low), 1/50 LD50 (3.74 mg/kg, medium), and 1/25 LD50 (7.48 mg/kg, high) dose groups. After oral cadmium exposure for 40 days, the pallium of mice was obtained for microstructure and ultrastructure studies. The results showed that both microstructure and ultrastructure alterations of the pallium were observed in all treated mice and the most obvious alterations were in the high dose group. Microstructural analysis showed seriously congested capillary in the pia mater of the pallium in the high cadmium group. Meanwhile, vacuolar degenerate or karyopyknosis presented in some neurocytes, capillary quantity, and the number of apoptotic cells increased, some neurocytes became hypertrophy, the pia mater separated from the cortex, and local hemorrhage and accompanied inflammatory cell infiltration were also observed. Ultrastructural analysis showed that rough endoplasmic reticulum was expanded, heterochromatin marginalized, perinuclear space distinctly broadened, swelling and vacuolization mitochondria appeared, synapse was swelling, presynaptic and postsynaptic membranes presented fusion, and most of mitochondrial cristae were ambiguous. The results indicated that cadmium exposure for 40 days induced dose-dependent microstructure and ultrastructure alterations in pallium of immature mice.
TL;DR: It is demonstrated that ATVF in flower petals is accompanied with the sequestration of the cytoplasmic sectors located between the neighboring cell wall ingrowths, the ultrastructure of which has been reported in the present work for the first time.
Abstract: Autophagy in flower petal epidermal cells is a little studied process. However, it is of interest regarding the physiology of chlorophylless plant tissues. We show that the utilization of organelles in the Petunia hybrida L. flower petal epidermis occurs via the autophagic-like organelle targeting into vacuole during the particular process of vacuole fragmentation and growth of secondary vacuoles (ATVF). It differs from macroautophagy (formation of autophagosome) and microautophagy. Peroxisomes were shown to be subjected to both macroautophagy (as single microbodies and their assemblies) and to ATVF when they are in complexes with mitochondria and chromoplasts. In addition, we have demonstrated that ATVF in flower petals is accompanied with the sequestration of the cytoplasmic sectors located between the neighboring cell wall ingrowths, the ultrastructure of which has been reported in the present work for the first time. It has been shown there are more numerous mitochondria, a more pronounced ATVF, and a thicker cytoplasmic layer in the blue tissues, possibly reflecting more intensive metabolic processes in them compared to white tissues. We assume that these differences may be of interest for the further studies and may be discussed including in terms of anthocyanin-dependent photochemical effects.
TL;DR: The morphology and ultrastructure of the male reproductive system in two species of sharpshooter leafhoppers were investigated in Cicadella viridis and Kolla paulula, whose sperm can be distinguished from those of other Cicadellidae by the accessory bodies and mitochondrial derivatives with gap region.
Abstract: 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.
TL;DR: Results on the functional ultrastructure of eggs and cellular organization of hexacanths support the phylogenetic distinction between T. congolensis and cestodes of the subfamily Anoplocephalinae.
Abstract: The functional ultrastructure of eggs and cellular organization of hexacanths from gravid proglottids of Thysanotaenia congolensis, from black rats from Cape Verde, were examined by transmission electron microscopy. Mature eggs with fully formed hexacanths are grouped within parenchymatous capsules of gravid proglottids. Oncospheral envelopes surrounding mature hexacanths are reduced to a very thin membranous embryophore as their protective function is taken over by the parenchymatous capsules originating from the medullary parenchyma of immature proglottids and composed of three layers. Six major cell types are present: a bi-nucleate medullary centre; a six-nucleate U-shaped penetration gland; a second type of penetration gland; two neurosecretory-type nerve cells; about 30 somatic cells; and about 12 germinative cells. Present results on the functional ultrastructure of eggs and cellular organization of hexacanths support the phylogenetic distinction between T. congolensis and cestodes of the subfamily Anoplocephalinae.
TL;DR: The thin sections and ultrastructure examination show that the epithelium of both organs is morphologically similar and composed of supporting cells, sensory cells and different types of secretory cells, there is a certain specialization in their secretory product.
Abstract: In this study, we describe the microstructure and ultrastructure of the epipodial papillae and epipodial tentacles of Haliotis tuberculata using light and electron microscopy. The epipodial papillae vary morphologically; they are subdivided into several subpapillae whose surface is covered by small micropapillae. The epipodial tentacles are large extendable conically elongated structures whose surface is differentiated in two regions: the dorsal region with long corrugated folds, and a ventral region composed of three parts, a basal part with the same structure as the dorsal, a middle part with shorter corrugated folds and an apical part with large micropapillae. Although the thin sections and ultrastructure examination show that the epithelium of both organs is morphologically similar and composed of supporting cells, sensory cells and different types of secretory cells, there is a certain specialization in their secretory product. Although the epithelium of both structures was positive for acidic glycoconjugates, the tentacle epithelium was also positive for neutral sugars. Further specific differences were revealed by lectin histochemistry. Because papillae and tentacles can be extended or retracted depending on environmental conditions, they probably have tactile and olfactory functions.