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Frozen bacterial cells were low-temperature embedded after cryosubstitution at 185K in organic solvent. Temperature elevation of cryosubstituted E. coli cells, when still in organic solvent, had no effect on the preservation of chromatin structure. The achieved stabilization was found to be established independent of the presence of the chemical fixative. Cryosubstitution without the use of a chemical...
In this essay with a flavor of science history, the influence of imaging techniques, as compared to other research strategies, on microbiologic investigations is discussed. Using a few selected examples, to what degree microbiology became a leading science during the last 50 years in gaining knowledge in life sciences, particularly with regard to molecular genetics and more recently molecular evolution...
Three different methods are currently used for the study of high-resolution structures of membrane proteins: X-ray crystallography, electron crystallography, and nuclear magnetic resonance (NMR) spectroscopy. Thus far, all methods combined have yielded a rather modest number of crystal structures that have been solved at the atomic level. It is hypothesized here that different methods may select different...
The fission yeast Schizosaccharomyces pombe has been used as a model organism to study cell cycle control and dynamic chromosome behavior during anaphase segregation as genetic and cytological approaches are easily amenable. To understand the role of gene products involved in these cellular events, it is important to determine intracellular localization of each gene product during the cell cycle....
Microscopic inspection of heterogenous three-dimensional (3D) objects such as oral implants, or implants in general, is conventionally performed either on ground sections of methyl-metacrylate-embedded material, at the cellular level by histologic analysis of the peri-implant tissue by light microscopy (LM), or at the supramolecular level by transmission electron microscopy (TEM). Alternatively, the...
Eduard Kellenberger understood that the conventional resin-embedding, he helped to develop (Ryter, A., Kellenberger, E., 1958. L'inclusion au polyester pour l'ultramicrotomie. J. Ultrastruct. Res., 2, 200–214), was prone to aggregation artifacts (Kellenberger, E., 1987. The response to biological macromolecules and supramolecular structures to the physics of specimen cryo-preparation. In: Steinbrecht,...
Chaperonins are key components of the cell machinery and are involved in the productive folding of proteins. Most chaperonins share a common general morphology based in a cylinder composed of two rings of 7–9 subunits, with a conspicuous cavity inside the particle. Chaperonins have been classified into two groups according to their sequence homologies: type I, whose better known member is GroEL, and...
There were times when any progress in science was associated with a social benefit. Public support of science was growing continuously without many questions being asked. These times have gone and the public asks now what science is good for and scientists are not yet well prepared to reply. A new social contract between scientists and society should be elaborated based on knowledge, tolerance and...
In the scanning transmission electron microscope (STEM) an electron beam of a few angstroms diameter is raster scanned over a thin sample and the scattered electrons are sequentially measured for each sample element irradiated. The mass, the elemental composition and the structure of a protein can be simultaneously assessed if all detector systems of the STEM are used. Aspects affecting the accuracy...
In eukaryotes standard initiation of translation involved 40S ribosome scanning to bridge the distance from the cap to the initiation codon. Recently deviations from that rule had been described, including “internal initiation”, “poly-A dependent translation”, and “ribosome shunting”. In ribosome shunting, ribosomes start scanning at the cap but large portions of the leader are skipped. Thereby the...
Various DNA-based methods are presently being applied for identification of industrial bacterial cultures including dairy starter and probiotic strains of Lactobacillus. The success of strain-specific identification depends on the power of the DNA-based methods to reveal intraspecies DNA polymorphism. This study reveals that all eleven arbitrarily chosen Lactobacillus rhamnosus starter, laboratory...
The application of atomic force microscopy (AFM) to probe the ultrastructure and physical properties of microbial cell surfaces is reviewed. The unique capabilities of AFM can be summarized as follows: imaging surface topography with (sub)nanometer lateral resolution; examining biological specimens under physiological conditions; measuring local properties and interaction forces. AFM is being used...
The slow-strain-rate test technique was used to evaluate the susceptibility of Ti Gr-7 and Ti Gr-12 to hydrogen-induced-cracking and/or stress corrosion cracking . Ti Gr-7 and Ti Gr-12 are two candidate container materials for the multi-barrier package for nuclear waste. The tests were done in a deaerated 90 o C acidic brine (pH~2.7) containing 5 weight percent (wt.%) NaCl using a strain rate...
The ability of phosphatidylcholine (PC) liposomes to protect pig stratum corneum (SC) against the action of the nonionic surfactant octyl glucoside (OG) was investigated ''in vitro'' using double-layer coating for high-resolution, low-temperature scanning electron microscopy. This technique has been useful in preventing drying artifacts in the study of biological materials. The treatment of SC with...
Ciliated protozoans represent useful organisms for studying the processes involved in the induction and progression of meiosis. In this short report we describe a technique that has allowed us to examine different meiosis phases during the sexual reproduction of Blepharisma japonicum. In order to visualize the phases of meiosis, sexually reproducing pairs were stained by an enhanced technique of anti-tubuline...
The technique of off-axis electron holography is introduced and reviewed. The history of the topic is discussed briefly looking at the origin of electron holography and the reasons for its growth in recent years around the world. The formation and numerical reconstruction of the hologram is discussed in detail on a theoretical and practical level. The spread of holography is illustrated through a...
The gonads of glow worm larvae are enveloped by adipose tissue which represents a specialized fat body. The adipose gonadal envelope, and also to a lesser extent the fat body cells, contain tubular paracrystalline inclusion bodies (PIBs). Cells of other tissues are devoid of such inclusions. The PIBs form in the cisternae of rough ER. In young larvae PIB formation is sparse, but at advanced larval...
Non-stoichiometric CuInS 2 is a novel material for thin film solar cells. Electron energy loss spectrometry analysis shows that there are considerable lateral inhomogeneities on a scale of less than 100nm. It is as yet unknown whether the Cu or In surplus comes in nanoprecipitates irregularly distributed in the otherwise stoichiometric matrix, or forms supercells where particular atoms are...
The study's purpose was to obtain improved ''deplasticizing'' of epoxy sections for immunoelectron microscopy. Epoxy-embedded renal swine tissue with immune complex deposits was used. Ultrathin sections were mounted on uncoated grids or on carbon-stabilized formvar grids. The sections were exposed to different concentrations of sodium ethoxide, and they were subjected to immunogold labeling with anti-IgG...
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