Use Of Polarized Microscopy Research Articles

Periphyton (microbiome) of filamentous algae studied by polarization microscopy, aided also by some contrasting optical methods.

Polarization microscopy, possibly together with some contrast techniques (dark field and color phase contrast), was used to study the periphyton (microbiome) growing on filamentous green algae. The material containing filamentous algae with periphyton on the surface was collected in the villages of Sýkořice and Zbečno (Křivoklátsko Protected Landscape Area). The objects were studied in a LOMO MIN-8 St. Petersburg polarizing microscope and a Carl Zeiss Jena NfpK laboratory microscope equipped with an In Ph 160 basic body with variable dark field or color phase contrast and a Nikon D70 DSLR digital camera. Cells of filamentous algae of the genera Cladophora, Vaucheria, and Oedogonium were studied and the periphyton attached to them formed by cyanobacteria of the genera Chamaesiphon and Pleurocapsa and algae of the genera Characium, including diatoms of the genera Eunotia and Synedra. In all cases, the cell walls of the host algae showed a very strong birefringence. In contrast, the walls of cyanobacteria of the genera Chamaesiphon and Pleurocapsa were characterized by a much weaker birefringence (Pleurocapsa somewhat thicker), and the diatom frustules of the genera Eunotia and Synedra were almost without a birefringence. Strongly birefringent granules were found in the cytoplasm of the green alga of the genus Characium, which forms periphyton on the filamentous green algae of the genus Vaucheria. The periphyton on the filamentous alga of the genus Oedogonium, formed by cyanobacteria of the genus Pleurocapsa and diatoms of the genera Eunotia and Synedra, deposited in a massive layer of mucus containing birefringent crystals, showed a particularly strong birefringence. At the end of the vegetation of filamentous algae, their parts and remnants of periphyton (diatom frustules and crystals) became part of the detritus at the bottom of the culture vessel. The use of polarization microscopy in the study of filamentous algae with periphyton on the surface allows us not only to determine the birefringence of the observed structures, but also to partially deduce their chemical composition, or regular arrangement ofparticles, so-called shape birefringence.

Simultaneous use of polarization microscopy and dark field techniques in the study of microorganisms.

Simultaneous application of polarization microscopy and dark field techniques has been used to study the internal structure of microbial cells. The dark field technique displays subtle cell structures like glowing objects on a dark background. In the polarizing microscope, cross polarizing filters along with the first-order quartz compensator and a rotary table show the maximum birefringence of the individual structures. The material containing microorganisms was collected in the villages of Sýkořice and Zbečno (Křivoklátsko Protected Landscape Area). The objects were studied in a laboratory microscope Carl Zeiss Jena type NfpK equipped with In Ph 160 basic body with variable dark field, special condenser with interchangeable diaphragm apertures, a rotary table, Meopta Praha polarizer, analyzer, first-order quartz compensator from LOMO Sankt Petersburg, and a digital Nikon D 70 DSLR camera. Three orders of microorganisms were studied: Siphonocladales, Chlorococcales, and Peritricha. Anisotropic structures in different amounts and sizes (e.g., granules and microfibrils) or in different configurations (e.g., cell walls or pellicle) have been found in all Protista organisms under study. Filamentous algae of the genus Cladophora (Cladophoraceae, Siphonocladales, Ulvophyceae) featured a strongly birefringent cell wall (shape birefringence) surrounded by less birefringent periphyton (microbial biofilm), at the edges of which cyanobacterial fibers could be recognized-a very important finding. The coccal algae of the genus Scenedesmus (Scenedesmataceae, Chlorococcales, Chlorophyceae) exhibited not only strongly birefringent granules, but also strongly birefringent microfibrils in the cytoplasm outside the strongly birefringent cell walls-very important finding. Of all the studied microorganisms, the weakest birefringence was shown in the surface membrane (pellicle) of the Vorticella (Vorticellidae, Peritricha, Ciliata). On the other hand, the ring of cilia on the top of the body had a somewhat stronger birefringence-an important finding. In conclusion, the dark field technique provides a high contrast image in the microscope and, if supplemented simultaneously by polarization microscopy, will allow us to partially infer the composition of the examined structures.

Analysis of the Ratio of Collagen Types I and III in Skin and Aponeurosis in Patients with Ventral Hernias

Relevance Disorder of the connective tissue remodeling in patients after surgical treatment of ventral hernias is the great problem of modern herniology. Pathology of the connective tissue is considered as the main cause of this disorder, and is closely connected with the disturbance of collagen metabolism in the zone of post operation scar. The purpose of the study Study the relationship between collagen type I and III of the connective tissue in skin and aponeurosis in patients with hernia disease and with another surgical pathology. Materials and methods Comparative investigation of the skin and aponeurosis connective tissue structure was performed in 95 patients, suffering from ventral hernias, with the help of polarization microscopy. All patients were divided into two groups: 46 patients with ventral hernias and 49 patients with another surgical pathology. Results and their discussion In patients with hernias had significantly lower ratio of TC (p≤0,001) as in the preparation of the skin, and aponeurosis compared with patients without hernia. It was revealed strong direct correlation dependence between the connective tissue structure of skin and of aponeurosis, which makes the prognosis of ventral hernia development possible with the help of investigation of the skin structure. Conclusion In patients with WG had significantly (P ≤ 0,001) lower ratio of TC in the skin and aponeurosis. Collagen composition of the connective tissue of the skin and aponeurosis are in a strong direct correlation (r=0,72), which makes it possible to judge the changes in the structure of the aponeurosis in terms of the ratio of collagen in the skin. The use of polarization microscopy to determine the proportion of collagen types I and III in the preparations of the skin and aponeurosis is highly informative in the verification of hernia disease

Optimizing TESE‐ICSI by laser‐assisted selection of immotile spermatozoa and polarization microscopy for selection of oocytes

For most azoospermic men testicular sperm extraction (TESE) is the only treatment, however it presents challenges for the ART laboratory, as the retrieval of motile spermatozoa is difficult. In the absence of sperm movement no unequivocal distinction can be made between either dead or immotile, but vital spermatozoa. However, a single laser shot directed to the tip of the tail allows recognition of viability because the flagellum coils at the area of impact. To rank the quality and the maturity of oocytes, polarization microscopy can be used. The zona score and the visualization of the meiotic spindle correlate with implantation and pregnancy rates. We compared 65 TESE-ICSI cycles of the years 2007 and 2008 (Group 1, G1) with 58 TESE-ICSI cycles of the years 2009 and 2010 (Group 2, G2). Testicular spermatozoa were injected according to motility and morphology into selected oocytes. In G1 both, oocyte and spermatozoa were rated using light microscopy only, whereas in G2 the laser was used for sperm selection and the oocytes were rated by light and polarization microscopy. In G2 we enhanced our fertilization rate (FR) significantly in comparison to G1 (G1 42.1% vs. G2 52.7%, p<0.001). The fertilization rate with immotile, but vital spermatozoa improved significantly when applying laser-based selection (p=0.006). The laser selection of immotile spermatozoa and the use of polarization microscopy can enhance the FR of TESE-ICSI. No negative effect of the laser was seen on birth rates. The FR with immotile, but vital spermatozoa clearly benefits from laser selection and is a non-hazardous and safe method for the selection of viable but immotile sperm. To our knowledge this is the first report using new technology creating novel endpoints for the analysis of spermatozoa and oocytes in TESE-ICSI.

Gamete competence assessment by polarizing optics in assisted reproduction

The purpose of this study was first to give an overview of the historical development of polarization microscopy, second to describe the various applications of this technique in assisted reproduction techniques (ART) and third to discuss the potential benefit of polarization microscopy as a predictor for IVF success. The history of polarization microscopy was undertaken by performing a backward search in the scientific literature using Google and internet sites of several Societies for Microscopy and Cell Biology. Studies of polarization microscopy in ART were identified by using a systematic literature search in PubMed and Scopus. A total of 62 articles were identified by the direct search and further relevant articles were found by screening the cited literature in these articles. The topics relevant for assisted reproduction were spindle and zona imaging in combination with IVF success, meiotic cell cycle progression, pharmaceutical studies and cryopreservation. A separate topic was the use of sperm birefringence in ART. The majority of studies are observational studies and were not performed in a randomized manner and there is no direct comparison of techniques using other gamete selection markers. Despite this, most studies show that polarization microscopy may help us to further increase our knowledge on gametes and meiosis. Whether certain applications such as spindle or zona imaging may lead to an increase in IVF success is unclear at present. Publications on the use of polarization microscopy on sperm are still very limited.

Magnetic-field-induced nematic–nematic phase separation and droplet formation incolloidal goethite

We demonstrate the suitability of polarization microscopy to study the recently discovered(parallel) nematic–(perpendicular) nematic phase separation. This novel type ofphase transition is induced by applying an external magnetic field to a nematicliquid crystal of boardlike colloidal goethite and is due to an interplay betweenthe intrinsic magnetic properties of goethite and the collective effect of liquidcrystal formation. It is shown that the intense ochre colour of goethite does notpreclude the use of polarization microscopy and interference colours, and thatdichroism can give valuable qualitative information on the nature of the phases,their anchoring and their sedimentation and order parameter profiles. We alsoapply these techniques to study ‘nematic–nematic tactoids’: nematic dropletssedimenting within a nematic medium with mutually perpendicular orientations.

Crystal solvates of thermotropic alkylenearomatic copolyesters and poly(m-phenyleneisophthalamide) with N-methylmorpholine-N-oxide

The dissolution of thermotropic alkylenearomatic LC copolyesters and isotropic poly(m-phenyleneisophthalamide) in a high-polarity donor solvent, N-methylmorpholine-N-oxide, has been studied. It has been demonstrated that N-methylmorpholine-N-oxide shows high dissolving power with respect to hydrophobic synthetic polymers. In this case, the dissolution of the polymers is accompanied by the formation of crystal solvates of different compositions. With the use of polarization microscopy, DSC, and X-ray diffraction, the stages of formation of crystal solvates have been examined and the phase equilibrium in systems containing crystal solvates has been investigated. Special attention is given to the structural and morphological features of such heterophase systems.

Friberg Correlations in Oil Recovery

The current status of “Friberg correlations” is reviewed and illustrated in model and industrial systems relevant to the oil industry. For a model naphthenic acids/sodium hydroxide two‐phase system, a third, liquid crystal (LC), phase is formed at the o/w interface from sodium naphthenates, which is produced in situ by a chemical reaction. This LC layer spreads spontaneously on the o/w interface, thus it is a “surface‐active phase” in the sense defined by R. G. Laughlin. When this additional phase covers the oil/water interface it modifies the transport processes throughout the interface. The LC layers on water droplets may be one of the reasons for the high water‐in‐oil emulsion stability observed in industrial systems. This suggestion is supported by the increased stability of water‐in‐bitumen emulsions doped with sodium naphthenates at concentrations higher than 50 ppm. The stability of the emulsion droplets can be further enhanced by capturing solid particles or precipitated asphaltenes at the LC‐coated interfaces. At equilibrium, optically anisotropic structures are detected in the bitumen/water/sodium hydroxide system, indicating the presence of a liquid crystal (LC) phase in industrial systems. The possible source of errors and proper use of polarization microscopy are discussed for LC phase containing emulsions.

The use of polarization microscopy in the diagnosis of pneumocystis pneumonia.

The use of polarization microscopy in the diagnosis of pneumocystis pneumonia.

Congo red dichroism with dispersed amyloid fibrils, an extrinsic cotton effect.

The spectral absorption, optical rotatory dispresion, and circular dichroism associated with interaction of Congo red dye with partly purified suspensions of amyloid fibril fragments were examined. A set of phenomena consistent with a Cotton effect was found. A nearly identical set of phenomena was obtained with poly-L-lysine in its alpha-helical form. The dichroism seen when Congo red binds to amyloid substance in tissue sections can also be interpreted as a Cotton effect. This suggests that some special conformation, presumably in protein, is present in a major constituent of amyloid. This conformation is not present in gamma globulin, Bence-Jones protein, albumin, fibrinogen, or other proteins tested so far. These and other optical properties of amyloid substance can be used to compare amyloid deposits in different human cases and in different species. Extension of the use of polarization microscopy with other dyes that bind to other substances in tissue sections should permit more exquisite probing of the conformation of important macromolecules in situ in cells and tissues than has hitherto been possible.