scholarly journals The Polygonal Cell Shape and Surface Protein Layer of Anaerobic Methane-Oxidizing Methylomirabilislanthanidiphila Bacteria

2021 ◽  
Vol 12 ◽  
Author(s):  
Lavinia Gambelli ◽  
Rob Mesman ◽  
Wouter Versantvoort ◽  
Christoph A. Diebolder ◽  
Andreas Engel ◽  
...  
Keyword(s):  
Cell Shape ◽  
Surface Protein ◽  
Nitrite Reduction ◽  
Immunogold Localization ◽  
Hexagonal Symmetry ◽  
Protein Layer ◽  
Thin Sections ◽  
Whole Cells ◽  
Polygonal Cell ◽  
Determining Factor

Methylomirabilis bacteria perform anaerobic methane oxidation coupled to nitrite reduction via an intra-aerobic pathway, producing carbon dioxide and dinitrogen gas. These diderm bacteria possess an unusual polygonal cell shape with sharp ridges that run along the cell body. Previously, a putative surface protein layer (S-layer) was observed as the outermost cell layer of these bacteria. We hypothesized that this S-layer is the determining factor for their polygonal cell shape. Therefore, we enriched the S-layer from M. lanthanidiphila cells and through LC-MS/MS identified a 31 kDa candidate S-layer protein, mela_00855, which had no homology to any other known protein. Antibodies were generated against a synthesized peptide derived from the mela_00855 protein sequence and used in immunogold localization to verify its identity and location. Both on thin sections of M. lanthanidiphila cells and in negative-stained enriched S-layer patches, the immunogold localization identified mela_00855 as the S-layer protein. Using electron cryo-tomography and sub-tomogram averaging of S-layer patches, we observed that the S-layer has a hexagonal symmetry. Cryo-tomography of whole cells showed that the S-layer and the outer membrane, but not the peptidoglycan layer and the cytoplasmic membrane, exhibited the polygonal shape. Moreover, the S-layer consisted of multiple rigid sheets that partially overlapped, most likely giving rise to the unique polygonal cell shape. These characteristics make the S-layer of M. lanthanidiphila a distinctive and intriguing case to study.

Video Graphics and High-Voltage Electron Microscopy For Analysis of Microtubule Distributions In Fixed Cells

1990 ◽  
Vol 48 (1) ◽  
pp. 524-525
Author(s):  
Richard Mcintosh ◽  
David Mastronarde ◽  
Kent McDonald ◽  
Rubai Ding
Keyword(s):  
Electron Microscopy ◽  
Cross Sections ◽  
Cell Shape ◽  
Video Camera ◽  
Computer Memory ◽  
High Voltage Electron Microscopy ◽  
Thin Sections ◽  
Voltage Electron ◽  
Morphogenetic Event ◽  
Set Of Points

Microtubules (MTs) are cytoplasmic polymers whose dynamics have an influence on cell shape and motility. MTs influence cell behavior both through their growth and disassembly and through the binding of enzymes to their surfaces. In either case, the positions of the MTs change over time as cells grow and develop. We are working on methods to determine where MTs are at different times during either the cell cycle or a morphogenetic event, using thin and thick sections for electron microscopy and computer graphics to model MT distributions.One approach is to track MTs through serial thin sections cut transverse to the MT axis. This work uses a video camera to digitize electron micrographs of cross sections through a MT system and create image files in computer memory. These are aligned and corrected for relative distortions by using the positions of 8 - 10 MTs on adjacent sections to define a general linear transformation that will align and warp adjacent images to an optimum fit. Two hundred MT images are then used to calculate an “average MT”, and this is cross-correlated with each micrograph in the serial set to locate points likely to correspond to MT centers. This set of points is refined through a discriminate analysis that explores each cross correlogram in the neighborhood of every point with a high correlation score.

The Surface Protein Layer of Methanoplanus limicola: Three-dimensional Structure and Chemical Characterization

1991 ◽  
Vol 14 (3) ◽  
pp. 209-217 ◽  
Author(s):  
Gang-Won Cheong ◽  
Zdenka Cejka ◽  
Jürgen Peters ◽  
Karl O. Stetter ◽  
Wolfgang Baumeister
Keyword(s):  
Three Dimensional ◽  
Chemical Characterization ◽  
Surface Protein ◽  
Dimensional Structure ◽  
Protein Layer ◽  
Three Dimensional Structure

scholarly journals THE CELL ENVELOPES OF TWO EXTREMELY HALOPHILIC BACTERIA

1963 ◽  
Vol 18 (3) ◽  
pp. 681-689 ◽  
Author(s):  
A. D. Brown ◽  
C. D. Shorey
Keyword(s):  
Single Unit ◽  
Cell Envelope ◽  
Halophilic Bacteria ◽  
Layered Compound ◽  
Halobacterium Halobium ◽  
Chemical Analyses ◽  
Unit Membrane ◽  
Thin Sections ◽  
Whole Cells ◽  
Cell Envelopes

The cell envelope of Halobacterium halobium was seen in thin sections of permanganate-fixed cells to consist of one membrane. This membrane appeared mostly as a unit membrane but in a few preparations it resembled a 5-layered compound membrane. The cell envelope of Halobacterium salinarium at high resolution was always seen as a 5-layered structure different in appearance from the apparent compound membrane of H. halobium. The "envelopes" which were isolated in 12.5 per cent NaCl from each organism were indistinguishable from each other in the electron microscope and comprised, in each case, a single unit membrane with an over-all thickness of about 110 A. Some chemical analyses were made of isolated membranes after freeing them from salt by precipitating and washing with trichloroacetic acid. Such precipitated membranes consisted predominantly of protein, with little carbohydrate and no peptido-aminopolysaccharide (mucopeptide). Sectioned whole cells of H. halobium contained intracellular electron-opaque structures of unknown function.

scholarly journals Exploring the Glycans of Euglena Gracilis

2017 ◽  
Author(s):  
Ellis C. O'Neill ◽  
Sakonwan Kuhaudomlarp ◽  
Martin Rejzek ◽  
Jonatan U. Fangel ◽  
Kathirvel Alagesan ◽  
...  
Keyword(s):  
Euglena Gracilis ◽  
High Capacity ◽  
Surface Protein ◽  
Protein Glycosylation ◽  
Plant Cell Walls ◽  
Beta Glucan ◽  
Whole Cells ◽  
Wide Range ◽  
Glycan Profiling ◽  
Complex Glycan

Euglena gracilis is an alga of great biotechnological interest and extensive metabolic capacity, able to make high levels of bioactive compounds, such as polyunsaturated fatty acids, vitamins and β-glucan. Previous work has shown that Euglena expresses a wide range of carbohydrate-active enzymes, suggesting an unexpectedly high capacity for the synthesis of complex carbohydrates for a single celled organism. Here we present an analysis of some of the carbohydrates synthesised by Euglena gracilis. Analysis of the sugar nucleotide pool showed that there are the substrates necessary for synthesis of complex polysaccharides, including the unusual sugar galactofuranose. Lectin- and antibody-based profiling of whole cells and extracted carbohydrates revealed a complex galactan, xylan and aminosugar based surface. Protein N-glycan profiling, however, indicated that just simple high mannose-type glycans are present and that they are partially modified with putative aminoethylphosphonate moieties. Together, these data indicate that Euglena possesses a complex glycan surface, unrelated to plant cell walls, while its’ protein glycosylation is simple. Taken together, these findings suggest that Euglena gracilis may lend itself to production of pharmaceutical glycoproteins.

A scale associated protein of Apedinella radians (Pedinellophyceae) and its possible role in the adhesion of surface components

1993 ◽  
Vol 104 (2) ◽  
pp. 391-398
Author(s):  
A. Koutoulis ◽  
M. Ludwig ◽  
R. Wetherbee
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Membrane ◽  
Cell Surface ◽  
Immunofluorescence Microscopy ◽  
Endomembrane System ◽  
Thin Sections ◽  
Specific Location ◽  
Whole Cells

Monoclonal antibodies have been generated against cell surface components of the unicellular phytoflagellate Apedinella radians (Pedinellophyceae). One monoclonal antibody, designated Arg 1E5/1B1, labels a scale associated protein (SAP) of 145 kDa. Immunofluorescence microscopy of whole cells as well as immunoelectron microscopy of whole cell mounts and thin sections using Arg 1E5/1B1 have shown that the SAP is located on the proximal surface of body scales and spine-scales. Its specific location suggests that the SAP may play a role in the adhesion of these surface components to the cell membrane and/or to one another. The potential of monoclonal antibody Arg 1E5/1B1 as a tool to study cell surface morphogenesis and the role of the endomembrane system in A. radians is discussed.

Physicochemical Studies on Artificial Surface/Protein/Platelet Interactions

1975 ◽  
Author(s):  
E. Nyilas ◽  
T.-H. Chiu ◽  
W. A. Morton ◽  
D. M. Lederman ◽  
G. A. Herzlinger ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Plasma Proteins ◽  
Platelet Adhesion ◽  
Surface Protein ◽  
Surface Proteins ◽  
Molecular Architecture ◽  
Number Density ◽  
Protein Layer ◽  
Artificial Surface ◽  
Lag Period

To highlight the mechanisms of artificial surface/protein/platelet interactions, results obtained by various methods have been integrated to elucidate some of the correlations between phenomena which occur at the macromolecular level and subsequently influence those at the cellular level, such as platelet adhesion. Microcinematographic evidence obtained under the controlled conditions of the Stagnation Point Flow Experiment (SPFE) indicate that, even on glass, platelet adhesion commences only after 30-60 sees of exposure to native blood. This lag period is consistent with diffusion kinetics predicting the arrival of plasma proteins should overhwelmingly precede that of the cellular components. During the lag period, native plasma proteins collide with the artificial surface and, in most cases, adsorb with surface-induced conformational changes. The energy for altering the secondary protein structure is supplied by the heat of adsorption. The extent of adsorption and structural alterations depend upon both the type of protein and the molecular architecture of the artificial surface, viz., the number density and orientation of polar, H-bonding, etc. groups accessible to proteins. Using microparticulate glass (< μ dia.) and a microcalorimeter sensitive to ±0.00001° C in 100 ml of sample volume, serum albumin was found to adsorb, release heat, and desorb in a conformationally altered state. In contrast, γ-(7S)-globulin and fibrinogen underwent irreversible multilayer attachment releasing (1.0-1.7) χ 103 Kcal/mole of protein adsorbed directly to the glass surface. Proteins in the second, etc. sorbed layers released much smaller heats. The electrophoretic mobility of the same particles coated with varying amounts of the same proteins confirmed that the relatively greatest conformational change occurred in the protein layer directly attached to the artificial surface. On homologous Nylons exposed under identical hemodynamic conditions in the SPFE, the surface number density of platelets remaining adherent at points of identical shear was proportionate to the polar force contribution of those surfaces. These results indicate that the protein layer which settles first, is acting as a “proportional transformer” mediating the effects of artificial surfaces onto platelets.

scholarly journals Cellular localization of D-lactate dehydrogenase and NADH oxidase fromArchaeoglobus fulgidus

Archaea ◽  
2002 ◽  
Vol 1 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Vishwajeeth Reddy Pagala ◽  
Joohye Park ◽  
David W. Reed ◽  
Patricia L. Hartzell
Keyword(s):  
Lactate Dehydrogenase ◽  
Cellular Localization ◽  
Nadh Oxidase ◽  
Optimal Growth ◽  
Binding Pocket ◽  
Integral Membrane Protein ◽  
Dissimilatory Sulfate Reduction ◽  
Gene Encoding ◽  
Thin Sections ◽  
Whole Cells

Members of the genusArchaeoglobusare hyperthermophilic sulfate reducers with an optimal growth temperature of 83 °C.Archaeoglobus fulgiduscan utilize simple compounds including D-lactate, L-lactate and pyruvate as the sole substrate for carbon and electrons for dissimilatory sulfate reduction. Previously we showed that this organism makes a D-lactate dehydrogenase (Dld) that requires FAD and Zn2+for activity. To determine the cellular location and topology of Dld and to identify proteins that interact with Dld, an antibody directed against Dld was prepared. Immunocytochemical studies using gold particle-coated secondary antibodies show that more than 85% of Dld is associated with the membrane. A truncated form of Dld was detected in immunoblots of whole cells treated with protease, showing that Dld is an integral membrane protein and that a significant portion of Dld, including part of the FAD-binding pocket, is outside the membrane facing the S-layer. The gene encoding Dld is part of an operon that includesnoxA2, which encodes one of several NADH oxidases inA. fulgidus. Previous studies have shown that NoxA2 remains bound to Dld during purification. Thin sections ofA. fulgidusprobed simultaneously with antibodies against Dld and NoxA2 show that both proteins co-localized to the same sites in the membrane. Although these data show a tight interaction between NoxA2 and Dld, the role of NoxA2 in electron transport reactions is unknown. Rather, NoxA2 may protect proteins involved in electron transfer by reducing O2to H2O2or H2O.

scholarly journals Stabilization of the shape of sickled cells by calcium and A23187

Blood ◽  
1976 ◽  
Vol 48 (6) ◽  
pp. 899-909 ◽  
Author(s):  
MR Clark ◽  
AC Greenquist ◽  
SB Shohet
Keyword(s):  
Cell Shape ◽  
Ionophore A23187 ◽  
Morphological Criterion ◽  
Calcium Dependent ◽  
Sickle Cells ◽  
Characteristic Morphology ◽  
Stabilizing Effect ◽  
Additional Support ◽  
Determining Factor

Abstract Evaluation of the role of calcium in irreversible sickling has been approached by treating sickled cells with calcium and the ionophore A23187. A calcium-dependent stabilization of the sickled cell shape was observed after reoxygenation of cells in the presence of ionophore. At low calcium concentrations, this retention of sickled shape was maintained for periods up to 1 hr. However, the morphology of the oxygen-stable sickled cells was like that of deoxygenated sickle cells and significantly different from the characteristic morphology of native irreversibly sickled cells (ISCs). Because the stabilized cells did not fulfill the morphological criterion for ISCs, the shape- stabilizing effect of calcium in this system did not provide additional support for the hypothesis that calcium accumulation was the determining factor in ISC generation.

Effect of Streptozotocin-Induced Diabetes on Estradiol-Stimulated Changes in the Ultrastructure of the Rat Endometrium

1981 ◽  
Vol 39 ◽  
pp. 532-533
Author(s):  
G.T. Frederick ◽  
R.M. Gardner ◽  
J.M. Kirkland ◽  
G.M. Stancel
Keyword(s):  
Electron Microscopic Examination ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Whole Cells ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Sprague Dawley Rats ◽  
Uterine Growth ◽  
Streptozotocin Induced Diabetes

Estradiol (E2)-stimulated uterine growth has been well characterized both biochemically and morphologically. Recent studies have shown that insulin plays an important role in the regulation of cellular development. This study examines the effect of streptozotocin-induced diabetes on E2-stimulated changes in the ultrastructure of the endometrium of the rat uterus.Sprague-Dawley rats were ovariectomized at 21 days of age. Diabetes, defined as blood glucose levels greater than 300mg%, was induced in half of these animals by the injection of 85mg streptozotocin/kg body weight.The remaining animals were classified as normal. Animals from both groups were injected with either 0.9% saline or 4μg E2/100gm body weight. At 18, 24, 36 and 48 hours post-injection of E2, uterine segments were collected from 8-10 animals in each experimental group and processed for electron microscopic examination. Uterine segments from saline-injected animals served as controls. Data summarized describe observations made from thin-sections and have not been extrapolated for whole cells.

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