scanning electron microscope
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Somatic embryogenesis (SE) is an important biotechnological technique used for the propagation of many pine species in vitro. However, in bog pine, one of the most endangered tree species in the Czech Republic, limitations were observed, which negatively influenced the development and further germination of somatic embryos. Although initiation frequency was very low-0.95 %, all obtained cell lines were subjected to maturation. The best responding cell line (BC1) was used and subjected to six different variants of the maturation media. The media on which the highest number of early-precotyledonary/cotyledonary somatic embryos was formed was supplemented with 121 μM abscisic acid (ABA) and with 6 % maltose. In the end of maturation experiments, different abnormalities in formation of somatic embryos were observed. For visualization and identification of abnormalities in meristem development during proliferation and maturation processes, the environmental scanning electron microscope was used. In comparison to the classical light microscope, the non-commercial environmental scanning electron microscope AQUASEM II has been found as a very useful tool for the quick recognition of apical meristem disruption and abnormal development. To our knowledge, this is the first report discussing somatic embryogenesis in bog pine. Based on this observation, the cultivation procedure could be enhanced and the method for SE of bog pine optimized.
- Klíčová slova
- Abnormalities, Environmental scanning electron microscope, Pinus uncinata subsp. uliginosa, Somatic embryogenesis,
- MeSH
- borovice růst a vývoj ultrastruktura MeSH
- klíčení MeSH
- mikroskopie elektronová rastrovací MeSH
- mokřady MeSH
- semena rostlinná růst a vývoj ultrastruktura MeSH
- somatická embryogeneze rostlin MeSH
- Publikační typ
- časopisecké články MeSH
In this paper we introduce new methodology for the observation of living biological samples in an environmental scanning electron microscope (ESEM). The methodology is based on an unconventional initiation procedure for ESEM chamber pumping, free from purge-flood cycles, and on the ability to control thermodynamic processes close to the sample. The gradual and gentle change of the working environment from air to water vapor enables the study of not only living samples in dynamic in situ experiments and their manifestation of life (sample walking) but also its experimentally stimulated physiological reactions. Moreover, Monte Carlo simulations of primary electron beam energy losses in a water layer on the sample surface were studied; consequently, the influence of the water thickness on radiation, temperature, or chemical damage of the sample was considered.
- MeSH
- metoda Monte Carlo MeSH
- mikrobiologie životního prostředí * MeSH
- mikroskopie elektronová rastrovací metody MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- voda MeSH
- MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- sluchové kůstky cytologie patologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Somatic embryogenesis is an important biotechnological technique which can be used in studies associated with environmental stress. Four embryogenic cell lines of Norway spruce were grown on media enriched with copper and arsenic in concentration ranges 50-500 μM and 10-50 μM, respectively. The effects were observed during subsequent stages of somatic embryogenesis, the characteristics evaluated being proliferation potential, average number of somatic embryos obtained per g/fresh weight, morphology of developed somatic embryos, metal uptake, and microanalysis of macro- and micronutrients uptake. Copper and arsenic at higher concentrations significantly reduced the growth of early somatic embryos. In almost all treatments, the cell line V-1-3 showed the best performance compared with the other lines tested. Environmental scanning electron microscopy was used to visualize and identify morphological abnormalities in the development of somatic embryos. Abnormalities observed were classified into several categories: meristemless somatic embryos, somatic embryos with disrupted meristem, reduced number of cotyledons, single cotyledon and fused cotyledons. With the application of a low temperature method for the environmental scanning electron microscope, samples were stabilized and whole meristems could be investigated in their native state. As far as we are aware, this is the first report of the effect of copper and arsenic during the process of somatic embryogenesis and the first to evaluate the content of macro and micronutrients uptake in Norway spruce.
- Klíčová slova
- Arsenic, Copper, Environmental scanning electron microscope, Picea abies (L.) Karst., Somatic embryogenesis,
- MeSH
- aktivní transport MeSH
- arsen farmakokinetika toxicita MeSH
- biotechnologie MeSH
- buněčné linie MeSH
- fyziologický stres MeSH
- klíčení účinky léků MeSH
- látky znečišťující životní prostředí farmakokinetika toxicita MeSH
- měď farmakokinetika toxicita MeSH
- mikroskopie elektronová rastrovací MeSH
- smrk účinky léků embryologie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- arsen MeSH
- látky znečišťující životní prostředí MeSH
- měď MeSH
Torulopsis ethanolitolerans subject to both the sparing and coarse heat treatment were studied in the scanning electron microscope. The reduction of adhesivity, increased permeability and higher rigidity of the yeast wall was achieved by an original glutaraldehyde-paraformaldehyde fixation, low osmolarity in vacuo and subsequent thiosemicarbohydrazide incubation, followed by addition of metal salt. The impregnation of the metal throughout the specimen due to the reaction of the thiosemicarbohydrazide with glutaraldehyde allowed viewing of small or intricate surface details of the yeast. Structural differences of the yeast processed by sparing and coarse heat treatment were shown to be better from the thiosemicarbohydrazide incubated samples compared to those that were prepared with osmium tetroxide.
- MeSH
- Candida ultrastruktura MeSH
- fixativa MeSH
- glutaraldehyd MeSH
- hydraziny MeSH
- mikroskopie elektronová rastrovací metody MeSH
- povrchové vlastnosti MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fixativa MeSH
- glutaraldehyd MeSH
- hydraziny MeSH
OBJECTIVE: The most important factors of long term clinical performance of biological heart valve prostheses are methods of processing and cryopreservation. That is why we decided to evaluate the impact of current Allograft Heart Valves (AHV) Bank protocol on valve tissue morphology. Scanning electron microscope (SEM) is a valuable tool for investigation of biological surfaces. In case of cardiac valves it is especially suitable for detection of fine changes in endothelial covering and underlying layers. MATERIAL AND METHODS: "Fresh" aortic and pulmonary AHV samples, harvested from "heart-beating" cadaveric donors, were compared with (1) tissue from AHV obtained from non heart-beating donors, (2) samples stored in 4 degrees C saline for 24 h, (3) antibiotic treated tissue for 24 h at 37 degrees C and finally (4) cryopreserved valves, stored in liquid nitrogen (-196 degrees C) for 6-38 months. All samples were dissected, dried with hexamethyldisilazane (HMDS), gold coated, studied and photographed by SEM (Tesla BS 301). RESULTS: Our alternative method of drying samples by the HMDS method proved to be suitable for thin membranes of human semilunar valves. We were able to detect early changes in the endothelium after harvesting, and denudation of the endothelial covering during preservation with and without freezing. CONCLUSION: SEM (using HMDS drying) along with other methods may be helpful for the morphological control of processing, cryopreservation and liquid nitrogen storage of AHV. According to the current findings we have to avoid washing of AHV in saline after harvesting.
BACKGROUND: Despite the fact that numerous reptile species are widely studied by the researchers, information describing the detailed structure of particular organs in many reptiles is missing. MATERIALS AND METHODS: The tongue of the sand lizard (Lacerta agilis) was examined under the light and scanning electron microscope. It is divided into bifurcated apex, corpus and bifurcated radix. The tip of the lingual apex is devoid of lingual papillae. RESULTS: The remaining dorsal surface of the tongue bears either fused papillae in the form of caudally directed ridges or individual papillae represented by mu- shroom-like or semilunar prominences (lingual apex) or fish scale-like papillae (lingual corpus) and horizontally laid ridges extending in the form of lobulated prominences (lingual corpus, lingual radix). Regardless of the shape, lingual papillae contain numerous muscle fibres and they are all considered to be mechanical. The lingual epithelium changes from the simple squamous into stratified squamous in the caudal direction. No salivary glands or sensory structures were recognised. CONCLUSIONS: This description is to be used mainly for comparative studies. It could also help to understand how different lizards capture the pray.
- Klíčová slova
- Lacertidae, lingual papillae, morphology, reptiles, scanning electron microscope,
- MeSH
- jazyk ultrastruktura MeSH
- ještěři anatomie a histologie MeSH
- mikroskopie elektronová rastrovací MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The analytical theory of statistical Coulomb interactions allows to determine the trajectory displacement in a single rotationally symmetrical beam with well-behaved spatial and angular particle distributions. This can be used to estimate the trajectory displacement in a multi-beam system using the so called fully-filled segment approximation. This approach predicts full compensation of trajectory displacement for a specific setup of the system. We show that this prediction is not consistent with Monte Carlo simulations and we develop a new approach to the calculation, showing that two independent trajectory displacement contributions are present in a multi-beam system. We support this calculation with Monte Carlo simulations as well as with experimental data from a multi-beam system.
- Klíčová slova
- Coulomb interactions, Electron optics, Multi-beam electron microscope, Slice method, Trajectory displacement,
- Publikační typ
- časopisecké články MeSH
The use of non-standard low-temperature conditions in environmental scanning electron microscopy might be promising for the observation of coniferous tissues in their native state. This study is aimed to analyse and evaluate the method based on the principle of low-temperature sample stabilization. We demonstrate that the upper mucous layer is sublimed and a microstructure of the sample surface can be observed with higher resolution at lower gas pressure conditions, thanks to a low-temperature method. An influence of the low-temperature method on sample stability was also studied. The results indicate that high-moisture conditions are not suitable for this method and often cause the collapse of samples. The potential improvement of stability to beam damage has been demonstrated by long-time observation at different operation parameters. We finally show high applicability of the low-temperature method on different types of conifers and Oxalis acetosella.
- Klíčová slova
- Oxalis acetosella, conifer, embryogenic tissue, extracellular matrix, methodology,
- MeSH
- cévnaté rostliny metabolismus ultrastruktura MeSH
- extracelulární matrix metabolismus ultrastruktura MeSH
- mikroskopie elektronová rastrovací metody MeSH
- nízká teplota * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The Raillietascaris varani (Baylis et Daubney, 1922), parasitic in the Indian monitor lizard, Varanus monitor (L.), was studied by scanning electron microscopy (SEM). A surface topography of the worm, especially the head and male tail, were described, illustrated and discussed with regard to the available data on this species, and also other species of ascaridoid nematodes. The present study confirms the previous observations from Sprent (1985), and also provides some additional information concerning the microtopography of the worm which might be useful in comparative studies on the Ascaridoidea.
- MeSH
- Ascaridoidea ultrastruktura MeSH
- ještěři parazitologie MeSH
- mikroskopie elektronová rastrovací MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
- Geografické názvy
- Indie MeSH
