Showing papers on "Ultrastructure published in 2015"
TL;DR: Ongoing development—including of dedicated probes, integrated microscopes, large-scale and three-dimensional EM and super-resolution fluorescence microscopy—now paves the way for broad CLEM implementation in biology.
Abstract: Microscopy has gone hand in hand with the study of living systems since van Leeuwenhoek observed living microorganisms and cells in 1674 using his light microscope. A spectrum of dyes and probes now enable the localization of molecules of interest within living cells by fluorescence microscopy. With electron microscopy (EM), cellular ultrastructure has been revealed. Bridging these two modalities, correlated light microscopy and EM (CLEM) opens new avenues. Studies of protein dynamics with fluorescent proteins (FPs), which leave the investigator 'in the dark' concerning cellular context, can be followed by EM examination. Rare events can be preselected at the light microscopy level before EM analysis. Ongoing development-including of dedicated probes, integrated microscopes, large-scale and three-dimensional EM and super-resolution fluorescence microscopy-now paves the way for broad CLEM implementation in biology.
387 citations
TL;DR: It is demonstrated that the exposure of phytoplankton to the insecticide chlorpyrifos leads to effects observed at both cellular and population level.
48 citations
TL;DR: A systematic method to characterize the ultrastructure of the intercellular space in the adult murine ventricle is developed and it is shown that PKP2 deficiency associates with ultrastructural defects.
Abstract: Aims Progress in tissue preservation (high-pressure freezing), data acquisition (tomographic electron microscopy, TEM), and analysis (image segmentation and quantification) have greatly improved the level of information extracted from ultrastructural images. Here, we combined these methods and developed analytical tools to provide an in-depth morphometric description of the intercalated disc (ID) in adult murine ventricle. As a point of comparison, we characterized the ultrastructure of the ID in mice heterozygous-null for the desmosomal gene plakophilin-2 ( PKP2 ; mice dubbed PKP2-Hz).
Methods and results Tomographic EM images of thin sections of adult mouse ventricular tissue were processed by image segmentation analysis. Novel morphometric routines allowed us to generate the first quantitative description of the ID intercellular space based on three-dimensional data. We show that complex invaginations of the cell membrane significantly increased the total ID surface area. In addition, PKP2-Hz samples showed increased average intercellular spacing, ID surface area, and membrane tortuosity, as well as reduced number and length of mechanical junctions compared with control. Finally, we observed membranous structures reminiscent of junctional sarcoplasmic reticulum at the ID, which were significantly more abundant in PKP2-Hz hearts.
Conclusion We have developed a systematic method to characterize the ultrastructure of the intercellular space in the adult murine ventricle and have provided a quantitative description of the structure of the intercellular membranes and of the intercellular space. We further show that PKP2 deficiency associates with ultrastructural defects. The possible importance of the intercellular space in cardiac behaviour is discussed.
35 citations
TL;DR: The findings elucidated the morphological mechanism that the exposure of cadmium changed the ultrastructure of cells in ovary tissues and clarified the cytotoxicity and pathological effects of Cadmium on the ovary.
Abstract: This study aimed at analyzing the cytotoxicity and pathological effects of cadmium on the ovary. Our studies revealed that cadmium was deposited in the mouse ovary after 8 d cadmium injection in vivo. Also, the increase in the rate of body weight was slowed, while the gonadosomatic index was reduced in the CdCl2 group, compared with the control group. Meanwhile, cadmium affected the maturation of follicles, the degradation of corpus luteum, the arrangement of follicles and corpus luteum, and increased the number of atresia follicles. Besides, under the electron microscope, chromatin margination, karopyknosis, swelling of mature cisternae of Golgi apparatus, mitochondrial cristae disappearance, and swelling of the rough endoplasmic reticulum can be observed in the CdCl2 group mice. Collectively, our findings elucidated the morphological mechanism that the exposure of cadmium changed the ultrastructure of cells in ovary tissues.
34 citations
TL;DR: Structural differences at nuclear, cytoplasmic and cytoskeletal level between normal and OA chondrocytes were shown.
Abstract: The aim of this study was to examine the ultrastructure and cytoskeletal organization in human normal and Osteoarhritic (OA) chondrocytes, exposed to interleukin-1β (IL-1β) and cyclic hydrostatic pressure (HP). Morphological examination by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed differences between normal and OA chondrocytes at the nuclear and cytoplasmic level. IL-1β (5 ng/mL) induced a decrease of the number of mitochondria and Golgi bodies and a significant increase on the percentage of cells rich in vacuolization and in marginated chromatin. Cyclical HP (1-5 MPa, 0.25 Hz, for 3 h) did not change the morphology of normal chondrocytes, but had a beneficial effect on OA chondrocytes increasing the number of organelles. Normal and OA cells subjected to IL-1β and HP recovered cytoplasmic ultrastructure. Immunofluorescence (IF) examination of normal chondrocytes showed an actin signal polarized on the apical sides of the cytoplasm, tubulin and vimentin uniformly distributed throughout cytoplasm and vinculin revealed a punctuated pattern under the plasma membrane. In OA chondrocytes, these proteins partially lost their organization. Stimulation with IL-1β caused, in both type of cells, modification in the cytoskeletal organization; HP counteracted the negative effects of IL-1β. Our results showed structural differences at nuclear, cytoplasmic and cytoskeletal level between normal and OA chondrocytes. IL-1β induced ultrastructural and cytoskeletal modifications, counteracted by a cyclical low HP.
32 citations
01 Jan 2015
TL;DR: This study demonstrates that by using a less traumatic surgical technique, it is possible to increase the cell survival rate of transplanted fat, thereby maintaining a certain number of viable cells and creating a volume increase in the grafted area.
31 citations
TL;DR: The ultrastructural analysis demonstrated high dynamics of the main cell organelles during the TRV PSG-Solanaceous plants interactions and suggest a relationship between organelle changes and different stages of virus infection cycle and/or particle formation.
29 citations
TL;DR: An important role of the cellular environment and long‐range interactions between chromatophores in promoting adult pigment pattern formation of trout are proposed.
Abstract: Skin pigmentation in animals is an important trait with many functions. The present study focused on two closely related salmonid species, marble trout (Salmo marmoratus) and brown trout (S. trutta), which display an uncommon labyrinthine (marble-like) and spot skin pattern, respectively. To determine the role of chromatophore type in the different formation of skin pigment patterns in the two species, the distribution and ultrastructure of chromatophores was examined with light microscopy and transmission electron microscopy. The presence of three types of chromatophores in trout skin was confirmed: melanophores; xanthophores; and iridophores. In addition, using correlative microscopy, erythrophore ultrastructure in salmonids was described for the first time. Two types of erythrophores are distinguished, both located exclusively in the skin of brown trout: type 1 in black spot skin sections similar to xanthophores; and type 2 with a unique ultrastructure, located only in red spot skin sections. Morphologically, the difference between the light and dark pigmentation of trout skin depends primarily on the position and density of melanophores, in the dark region covering other chromatophores, and in the light region with the iridophores and xanthophores usually exposed. With larger amounts of melanophores, absence of xanthophores and presence of erythrophores type 1 and type L iridophores in the black spot compared with the light regions and the presence of erythrophores type 2 in the red spot, a higher level of pigment cell organisation in the skin of brown trout compared with that of marble trout was demonstrated. Even though the skin regions with chromatophores were well defined, not all the chromatophores were in direct contact, either homophilically or heterophilically, with each other. In addition to short-range interactions, an important role of the cellular environment and long-range interactions between chromatophores in promoting adult pigment pattern formation of trout are proposed.
29 citations
TL;DR: The studies showed that the regionalization in the activity of cells occurs along the length of the hepatopancreatic tubules, and the first report on the existence of an intercellular junction that is connected with the E-cells of Crustacea is presented.
Abstract: The freshwater shrimp Neocaridina heteropoda (Crustacea, Malacostraca, Decapoda) originates from Asia and is one of the species that is widely available all over the world because it is the most popular shrimp that is bred in aquaria. The structure and the ultrastructure of the midgut have been described using X-ray microtomography, transmission electron microscopy, light and fluorescence microscopes. The endodermal region of the alimentary system in N. heteropoda consists of an intestine and a hepatopancreas. No differences were observed in the structure and ultrastructure of males and females of the shrimp that were examined. The intestine is a tube-shaped organ and the hepatopancreas is composed of two large diverticles that are divided into the blind-end tubules. Hepatopancreatic tubules have three distinct zones – proximal, medial and distal. Among the epithelial cells of the intestine, two types of cells were distinguished – D and E-cells, while three types of cells were observed in the epithelium of the hepatopancreas – F, B and E-cells. Our studies showed that the regionalization in the activity of cells occurs along the length of the hepatopancreatic tubules. The role and ultrastructure of all types of epithelial cells are discussed, with the special emphasis on the function of the E-cells, which are the midgut regenerative cells. Additionally, we present the first report on the existence of an intercellular junction that is connected with the E-cells of Crustacea.
28 citations
TL;DR: The results suggest that a detailed characterization of the link between changes in the ultrastructure and functionality of mitochondria during different nutritional conditions, can provide a successful approach to understand the role of these organelles in the plant response to Fe deficiency.
Abstract: Background
Mitochondria, as recently suggested, might be involved in iron sensing and signalling pathways in plant cells. For a better understanding of the role of these organelles in mediating the Fe deficiency responses in plant cells, it is crucial to provide a full overview of their modifications occurring under Fe-limited conditions. The aim of this work is to characterize the ultrastructural as well as the biochemical changes occurring in leaf mitochondria of cucumber (Cucumis sativus L.) plants grown under Fe deficiency.
Methodology/Results
Mitochondrial ultrastructure was investigated by transmission electron microscopy (TEM) and electron tomography techniques, which allowed a three-dimensional (3D) reconstruction of cellular structures. These analyses reveal that mitochondria isolated from cucumber leaves appear in the cristae junction model conformation and that Fe deficiency strongly alters both the number and the volume of cristae. The ultrastructural changes observed in mitochondria isolated from Fe-deficient leaves reflect a metabolic status characterized by a respiratory chain operating at a lower rate (orthodox-like conformation) with respect to mitochondria from control leaves.
Conclusions
To our knowledge, this is the first report showing a 3D reconstruction of plant mitochondria. Furthermore, these results suggest that a detailed characterization of the link between changes in the ultrastructure and functionality of mitochondria during different nutritional conditions, can provide a successful approach to understand the role of these organelles in the plant response to Fe deficiency.
27 citations
TL;DR: Methods for studying flagellar ultrastructure and biogenesis in two unicellular parasites-Trypanosoma brucei and Leishmania mexicana and the use of SBFSEM three-dimensional models for analysis of individual whole cells is demonstrated, demonstrating the excellent potential this technique has for future studies of mutant cell lines.
Abstract: Three-dimensional electron microscopy tools have revolutionized our understanding of cell structure and molecular complexes in biology. Here, we describe methods for studying flagellar ultrastructure and biogenesis in two unicellular parasites—Trypanosoma brucei and Leishmania mexicana. We describe methods for the preparation of these parasites for scanning electron microscopy cellular electron tomography, and serial block face scanning electron microscopy (SBFSEM). These parasites have a highly ordered cell shape and form, with a defined positioning of internal cytoskeletal structures and organelles. We show how knowledge of these can be used to dissect cell cycles in both parasites and identify the old flagellum from the new in T. brucei. Finally, we demonstrate the use of SBFSEM three-dimensional models for analysis of individual whole cells, demonstrating the excellent potential this technique has for future studies of mutant cell lines.
TL;DR: The pyrenoid ultrastructure with a double-layered thylakoid traversing the matrix, the shape of the starch envelope, as well as the cell wall, composed of glucosamine and developed around young autospores, were the features that allowed the thermophilic strain Chlorella R-06/2 to be classified as Ch Lorella vulgaris Beijerinck 1890.
Abstract: An extremophilic Chlorella strain R-06/2, isolated from a geothermal spring (+42 °C) in the region of Rupite village (SW Bulgaria), was investigated for species identification. This was done by observation of the cell morphology, reproduction and ultrastructure by light microscopy, scanning electron microscopy and transmission electron microscopy, and by investigation of the cell-wall chemistry. The pyrenoid ultrastructure with a double-layered thylakoid traversing the matrix, the shape of the starch envelope, as well as the cell wall, composed of glucosamine and developed around young autospores, were the features that allowed us to classify the thermophilic strain Chlorella R-06/2 as Chlorella vulgaris Beijerinck 1890.
TL;DR: The results revealed a number of new cytoskeletal elements associated with the lateral crest and the dorsal surface of the parasite and may contribute to an improved understanding of the structural organization of trophozoites.
TL;DR: This chapter presents the experimental workflow for combining live-cell fluorescence microscopy analysis with classical transmission electron microscopy, adapted for the studies of the centrosomes and basal bodies, and describes an approach that can be affordably and successfully employed in any typical cell biology laboratory.
Abstract: Correlative light and electron microscopy harnesses the best from each of the two modalities of microscopy it utilizes; while light microscopy provides information about the dynamic properties of the cellular structure or fluorescently labeled protein, electron microscopy provides ultrastructural information in an unsurpassed resolution. However, tracing a particular cell and its rare and small structures such as centrosomes throughout numerous steps of the experiment is not a trivial task. In this chapter, we present the experimental workflow for combining live-cell fluorescence microscopy analysis with classical transmission electron microscopy, adapted for the studies of the centrosomes and basal bodies. We describe, in a step-by-step manner, an approach that can be affordably and successfully employed in any typical cell biology laboratory. The article details all key phases of the analysis starting from cell culture, live-cell microscopy, and sample fixation, through the steps of sample preparation for electron microscopy, to the identification of the target cell on the electron microscope.
TL;DR: Golgi bodies, rough endoplasmic reticulum, and plastids filled with oil droplets were the predominant organelles in the epithelial cells of Tabernaemontana catharinensis A.DC.
Abstract: Colleters, which are glands that produce sticky secretion, have ecological and taxonomic relevance in Apocynaceae. We studied the distribution, morphology, ontogenesis, and cellular secretions of leaf colleters in Tabernaemontana catharinensis A.DC. Samples from mature embryos, seedlings, and plants were processed according to usual methods for anatomical, histochemical, and ultrastructural analyses. Colleters are non-vascularized emergences that occur on the adaxial face of expanded cotyledons, eophylls, and metaphylls and at the intrapetiolar and interpetiolar positions. Standard, bifurcate, trifurcate, and sessile colleters were found, and these glands did not differ in their ontogenesis, histochemistry, or histological composition. Golgi bodies, rough endoplasmic reticulum, and plastids filled with oil droplets were the predominant organelles in the epithelial cells. Mucilage accumulated in large periplasmic spaces, traversed the outer cell wall and the permeable cuticle, which remained intact. Senesc...
TL;DR: A protocol allowing extracting endothelial cell ultrastructure after having imaged the same cell in its in vivo context through live confocal imaging during zebrafish embryonic development is described.
Abstract: Live imaging is extremely useful to characterize the dynamics of cellular events in vivo, yet it is limited in terms of spatial resolution. Correlative light and electron microscopy (CLEM) allows combining live confocal microscopy with electron microscopy (EM) for the characterization of biological samples at high temporal and spatial resolution. Here we describe a protocol allowing extracting endothelial cell ultrastructure after having imaged the same cell in its in vivo context through live confocal imaging during zebrafish embryonic development.
TL;DR: In this article, the ultrastructure of mouse adenovirus keratitis was determined by transmission electron microscopy using a heat-pulled, glass, micropipette needle under compressed air.
Abstract: PURPOSE We determined the ultrastructure of mouse adenovirus keratitis, a model for human adenovirus keratitis. METHODS Adenovirus keratitis was induced in C57Bl/6j mice by intrastromal injection of human adenovirus species D type 37 (HAdV-D37) with a heat-pulled, glass, micropipette needle under compressed air. At select time points after infection, mice were euthanized and their corneas removed, fixed, and sectioned at 70-nm thickness for electron microscopy. RESULTS Injection of HAdV-D37 into the mouse corneal stroma placed virus predominantly in the pericellular corneal stromal matrix. Virus was seen bound to and entering stromal cells at 1 and 2 hours after infection, respectively. Cell membrane transit by virus was seen to involve two distinct structures resembling caveolae and macropinosomes. However, later during infection intracellular virus was not seen within membrane-bound organelles. By 8 hours after infection, intracellular virus had accumulated into densely packed, perinuclear arrays. Virus disassembly was not obvious at any time point after infection. Infiltrating neutrophils seen by one day after infection had engulfed degraded stromal cells by 4 days after infection. CONCLUSIONS By transmission electron microscopy, injected HAdV-D37 readily enters stromal cells in the C57Bl/6j mouse cornea and induces stromal inflammation, as was shown previously by light microscopy. However, electron microscopy also revealed dense, static arrays of intracytoplasmic virus, suggesting a block in viral capsid disassembly and viral DNA nuclear entry. These findings may explain why human adenoviruses do not replicate in the mouse corneal stroma.
TL;DR: According to the results, the P. homoion is degrading the blood components predominantly intracellularly.
Abstract: Paradiplozoon homoion is a representative of blood-feeding ectoparasites from the family Diplozoidae (Polyopisthocotylea, Monogenea). Although these worms have been the subject of numerous taxonomical, phylogenetic and ecological studies, the ultrastructure of the alimentary system and related structures, as well as the mechanisms of essential processes like fish blood digestion, remain mostly unknown. Our observation of P. homoion using a transmission electron microscopy (TEM) revealed two main types of digestive cells-U-shaped haematin cells and connecting syncytium. Particular structures such as mouth cavity with specialised receptors, two oval-shaped muscular buccal suckers, pharynx surrounded with the glandular cells, oesophagus, the intestinal caeca with intact erythrocytes in the lumen, the apical pinocytotic fibrous surface complex and haematin vesicles of U-shaped cells have been shown in detail. According to our results, the P. homoion is degrading the blood components predominantly intracellularly.
TL;DR: These morphological changes, observed in brain neurons in status epilepticus, are a reflection of epileptic pathophysiology and further studies at the chemical and molecular level of neurotransmitter release, such as at the level of porosomes at the presynaptic membrane, will further reveal molecular details of these changes.
TL;DR: Candida albicans and Candida tropicalis were treated with Streptococcus sanguinis bacteriocin and showed similar antifungal effect on C.a and C.t; their cell surface hydrophobicity, membrane permeability, and ultrastructure were changed significantly on exposure to S.s bacteriOCin.
Abstract: Candida albicans (C.a) and Candida tropicalis (C.t) were treated with Streptococcus sanguinis bacteriocin (S.s bacteriocin), respectively; the bacteriostatic dynamics of S.s bacteriocin, their effects on cell surface hydrophobicity, leakage of inorganic phosphorus and macromolecular substance, cytosolic calcium concentration, and ultrastructure changes of Candida thallus were detected and analyzed. The results showed that inhibitory effect of S.s bacteriocin on C.a and C.t reached peak level at 24 h, the cell-surface hydrophobicity decreased significantly (P < 0.05) after S.s bacteriocin treatment, and there was leakage of cytoplasmic inorganic phosphorus and macromolecular substance from C.a and C.t; cytosolic calcium concentration decreased greatly. After 24 h treatment by S.s bacteriocin, depressive deformity and defect could be found in the cell surface of C.a and C.t; the thallus displayed irregular forms: C.a was shrunken, there was unclear margins abutting upon cell wall and cell membrane, nucleus disappeared, and cytoplasm was inhomogeneous; likewise, C.t was first plasmolysis, and then the cytoplasm was shrunk, the ultrastructure of cell wall and cell membrane was continuously damaged, and the nucleus was karyolysis. It was illustrated that S.s bacteriocin had similar antifungal effect on C.a and C.t; their cell surface hydrophobicity, membrane permeability, and ultrastructure were changed significantly on exposure to S.s bacteriocin.
TL;DR: Comparison of the ultrastructure in two larch-trees characterized by different susceptibility to SO 2 appeared to be difficult due to the lack of synchronousness in the reaction of particular cells to this gas.
Abstract: Several changes have been observed in the ultrastructure of the mesophyll of larch needles under the effect of SO 2 swelling and degradation of the thylakoids, granulation of the cytoplasm and plastid matrix, degradation of the ribosomes and of endoplasmic reticulum, agglutination of the chromatin, and cell plasmolysis. Comparison of the ultrastructure in two larch-trees characterized by different susceptibility to SO 2 appeared to be difficult due to the lack of synchronousness in the reaction of particular cells to this gas.
TL;DR: The spermatozoa from testis and spermatheca of the plant-parasitic nematode Trichodorus similis Seinhorst, 1963 were studied with transmission electron microscopy (TEM), being the first study on sperMatogenesis of a representative of the order Triplonchida and important to unravel nematodes sperm evolution.
TL;DR: This work presents a methodology that facilitates processing of X. laevis tadpole eyes for electron microscopy by introducing an intermediate cryosectioning step and reproducibly provides a well-oriented tissue block that can be sectioned with minimal effort by a non-expert, and also allows retroactive analysis of samples collected on slides for light microscopy.
02 Sep 2015
TL;DR: The present chapter describes the layering structure and topochemistry of plant cell wall revealed by TEM.
Abstract: Plant cell walls are typically described as complex macromolecular composites consisting of an ordered array of cellulose microfibrils embedded in a matrix of noncellulosic polysaccharides and lignin. Generally, the plant cell wall can be divided into three major layers: middle lamella, primary cell wall, and secondary cell wall. Investigation of plant cell walls is complicated by the heterogeneous and complex hierarchical structure, as well as variable chemical composition between different sublayers. Thus, a complete understanding of the ultrastructure of plant cell walls is necessary. Transmission electron microscopy (TEM) has proven to be a powerful tool in elucidating fine details of plant cell walls at nanoscale. The present chapter describes the layering structure and topochemistry of plant cell wall revealed by TEM.
TL;DR: A novel method to combine cryosectioning with the maceration method for correlative immunocytochemical analysis has the potential to analyze the relationship between the distribution of functional molecules and the 3D ultrastructure in different composite tissues.
Abstract: Although the osmium maceration method has been used to observe three-dimensional (3D) structures of membranous cell organelles with scanning electron microscopy (SEM), the use of osmium tetroxide for membrane fixation and the removal of cytosolic soluble proteins largely impairs the antigenicity of molecules in the specimens. In the present study, we developed a novel method to combine cryosectioning with the maceration method for correlative immunocytochemical analysis. We first immunocytochemically stained a semi-thin cryosection cut from a pituitary tissue block with a cryo-ultramicrotome, according to the Tokuyasu method, before preparing an osmium-macerated specimen from the remaining tissue block. Correlative microscopy was performed by observing the same area between the immunostained section and the adjacent face of the tissue block. Using this correlative method, we could accurately identify the gonadotropes of pituitary glands in various experimental conditions with SEM. At 4 weeks after castration, dilated cisternae of rough endoplasmic reticulum (RER) were distributed throughout the cytoplasm. On the other hand, an extremely dilated cisterna of the RER occupied the large region of the cytoplasm at 12 weeks after castration. This novel method has the potential to analyze the relationship between the distribution of functional molecules and the 3D ultrastructure in different composite tissues.
TL;DR: Investigation of the effect on eukaryotic cells of the sudden loss of the F-actin cytoskeleton in yeast extract peptone dextrose medium found larger spherical cells with irregular morphology in the cell walls and ultrastructural disorder of the cell organelles and secretory vesicles.
Abstract: Our basic cell biology research was aimed at investigating the effect on eukaryotic cells of the sudden loss of the F-actin cytoskeleton. Cells treated with latrunculin A (LA) in yeast extract peptone dextrose (YEPD) medium were examined using phase-contrast and fluorescent microscopy, freeze-substitution, transmission and scanning electron microscopy, counted using a Burker chamber and their absorbance measured. The cells responded to the presence of LA, an F-actin inhibitor, with the disappearance of actin patches, actin cables and actin rings. This resulted in the formation of larger spherical cells with irregular morphology in the cell walls and ultrastructural disorder of the cell organelles and secretory vesicles. Instead of buds, LA-inhibited cells formed only ‘table-mountain-like’ wide flattened swellings without apical growth with a thinner glucan cell-wall layer containing β-1,3-glucan microfibrils. The LA-inhibited cells lysed. Actin cables and patches were required for bud formation and bud growth. In addition, actin patches were required for the formation of β-1,3-glucan microfibrils in the bud cell wall. LA has fungistatic, fungicidal and fungilytic effects on the budding yeast Saccharomyces cerevisiae.
01 Jan 2015
TL;DR: The results indicated that Cu have significant effects on Puntius javanicus hepatocyte ultrastructure, which provides additional knowledge about the elimination effects of copper for the evaluation of the health status of fish species toward exposure by this contaminant and as an alternative source for biomarker of metal toxicity.
Abstract: Histology assessment is necessary to verify the presence of liver toxicity. The present study was carried out to compare ultrastructure alterations affected by copper (Cu) in the liver of Puntius javanicus exposed in vivo for 96 hours to sublethal copper sulfate (CuSO4) concentration of 0.5, 1.0 and 5.0 mg/L. Our results indicated that Cu have significant effects on Puntius javanicus hepatocyte ultrastructure. The toxicity of copper was visualized using transmission electron microscope (TEM) where the effected cells show abnormalities of the shape of the nucleus, ripped nuclear membrane, swollen cells and lipid droplet deposition. However, at higher CuSO4 exposure, other abnormalities were observed which are the development of pyknotic nucleus along with damaged organelles such as mitochondria, Golgi apparatus and endoplasmic reticulum disorientation. Irreversible cell injury was also observed where the hepatic nuclei was undergoing karyorrhexis with the formation of apoptotic body consisted of free scattered damaged organelle. This comparative study provides additional knowledge about the elimination effects of copper for the evaluation of the health status of fish species such as Puntius javanicus toward exposure by this contaminant and as an alternative source for biomarker of metal toxicity.
TL;DR: Details of the ASC together with ultrastructure are potential features to subdivide the genus Gymnodinium, and molecular phylogeny supports that the genus Barrufeta is monophyletic, and that the genera Gymnadinium is polyphyletic.
Abstract: In the present study, we redescribed Gyrodinium resplendens through incubation of process bearing cysts extracted from sediment collected in the northern Gulf of Mexico. The morphology and ultrastructure of the motile stage and cyst stage were examined using light microscopy, scanning electron microscopy, and transmission electron microscopy and this revealed that the species should be transferred to the genus Barrufeta. This genus differs from other gymnodinioid genera in possessing a Smurf-cap apical structure complex (ASC) and currently encompasses only one species, Barrufeta bravensis. B. resplendens shows a Smurf-cap ASC that consists of three rows of elongated vesicles with small knobs in the middle one. B. resplendens is very similar to B. bravensis in cell morphology, but can be separated using the ultrastructure such as the shape and location of nucleus and pyrenoids, which highlights the importance of ultrastructure at inter-specific level in the genus Barrufeta. The unique cysts of B. resplendens are brown and process bearing, and have a tremic archeopyle with a zigzag margin on the dorsal side of the epicyst, and not polar as in cysts of Polykrikos. The cysts do not survive the palynological treatment used here and probably have a wide distribution. Maximum-likelihood and Bayesian inference were carried out based on partial large subunit ribosomal DNA (LSU rDNA) sequences. Molecular phylogeny supports that the genus Barrufeta is monophyletic, and that the genus Gymnodinium is polyphyletic. Our results suggest that details of the ASC together with ultrastructure are potential features to subdivide the genus Gymnodinium.
TL;DR: A functional role for glandular trichomes is suggested in the secretion of the putative phytotoxic allelochemical (-)HAA in aerial organs of Flourensia campestris and F. oolepis.
Abstract: In this work, the localization, density, morphology and ultrastructure of secretory structures in aerial organs of Flourensia campestris (FC) and F. oolepis (FO) (Asteraceae) by means of a combination of light, fluorescence, transmission (TEM) and scanning electron microscopy (SEM) were examined. The possible role of secretory structures in the production and secretion of the phytotoxic sesquiterpene (-)-hamanasic acid A ((-)HAA) in both species was also assessed. Capitate glandular trichomes were found in all reproductive organs of FC and FO, and were being reported for the first time. These glandular trichomes, typically associated to edges and veins, were of the same type as those already described for vegetative organs, and were abundant in involucral bracts and corolla of tubulose and ligulate flowers. Their density in reproductive organs of both species was similar (ca. 30/mm2) and lower than that found in leaves (ca. 100/mm2) and stems (ca. 160/mm2 in FC, and up to 650/mm2 in FO). Glandular trichomes in vegetative organs followed a species-specific pattern of distribution. TEM and SEM observations suggest that each species differs in the way in which secretory materials are released to the outside: through cracks or pores in FC, or through a loose cuticle in FO. Similar inspections of the secretory ducts revealed lipophilic vacuoles localized in subepithelial and epithelial cells, in which secretions accumulated before being transferred to the duct. The presence of wall ingrowths in subepithelial cells suggests that granulocrine secretion operates in these species. Secretory ducts varied in density and diameter among the organs in both species, with the combination being maximal in woody stems. (-)HAA was only detected in surface secreted resins of both species, and its concentration (2D-TLC, GC-FID) was intimately associated with the distribution and density of glandular trichomes in each organ (capitula, leaves, and stems with primary or secondary growth). In addition, no (-)HAA was detected internally in the resins collected from secretory ducts. The composition of these resins showed distinctive profiles for FC and FO, and only four from ca. 30 compounds detected (GC/MS) were shared by both species. In addition to the elucidation of ultrastructural traits, distribution and density of secretory structures in aerial organs of FC and FO, present findings suggest a functional role for glandular trichomes in the secretion of the putative phytotoxic allelochemical (-)HAA.
TL;DR: The results indicated that Pb induced distinct changes of the organelles including chloroplast, mitochondria, nucleolus and vacuole, which were relatively severe and relatively lighter than that without direct contact with Pb.
Abstract: Isoetes sinensis Palmer (Isoetaceae) is a critically endangered fern that is a marsh plant (that is an aquatic or amphibious plant) in China. To evaluate damage or influence of lead (Pb) on cell ultrastructure in I. sinensis, we used 2000mg·L-1 Pb(NO3)2 solution to treat I. sinensis for 35d, and used transmission electron microscope (TEM) to observe the cell ultrastructure of leaf blades and roots of the plant. Our results indicated that Pb induced distinct changes of the organelles including chloroplast, mitochondria, nucleolus and vacuole. The level of damage organ was lower leaf > upper leaf > root The typical performance of the damages caused by lead shown that part of the nucleolus cracked; the cristae dilated, matrix vacuolized and membrane structure blurred in mitochondria; the vacuole cracked; grana lamella decreased, stroma lamella loosed, starch grains decreased, and membrane structure was disrupted in chloroplasts; Pb deposits were present on cell wall. The damages to chloroplasts and mitochondria were relatively severe, while damage to the nucleus was relatively lighter. The damage to the cell ultrastructure of leaf blades with direct contact with Pb was more severe than that without direct contact with Pb.