Surface charge and morphogenesis of regular arrays of macromolecules on bacterial cell walls

1978 ◽  
Vol 36 (2) ◽  
pp. 346-347 ◽  
Author(s):  
U. B. Sleytr ◽  
G. P. Friers
Keyword(s):  
Cell Wall ◽  
Surface Charge ◽  
Bacterial Cell ◽  
Cell Walls ◽  
Surface Layers ◽  
Regular Surface ◽  
Wide Range ◽  
Freeze Etching ◽  
Regular Arrays ◽  
Peptidoglycan Layer

Regular arrays of macromolecules can be demonstrated on the surface of a wide range of bacteria by negative staining and freeze-etching techniques. The isolated subunits of the regular surface layers (S-layers) examined in this study have shown to consist of protein or glycoprotein and to possess the ability to assemble spontaneously under certain conditions to form regular arrays with the same dimensions as those seen on intact bacteria. In appropriate conditions the isolated subunits reattach to the cell wall from which they have been removed. Analysis of the orientation of the reconstituted S-layers have shown that the pattern of the regular arrays seem to be determined only by the directional bonds between the subunits and not by any order in the underlying (peptidoglycan) layer.

EXTRACELLULAR ENZYMES FROM STRAINS OF SORANGIUM

1965 ◽  
Vol 11 (1) ◽  
pp. 109-118 ◽  
Author(s):  
D. C. Gillespie ◽  
F. D. Cook
Keyword(s):  
Bacterial Cell ◽  
Cell Walls ◽  
Extracellular Enzymes ◽  
Soil Organisms ◽  
Wide Range ◽  
Bacterial Cell Walls

Soil organisms belonging to the myxobacter group and predatory on molds, yeasts, nematodes, and streptomycetes as well as on a wide range of bacteria elaborate at least two extracellular enzymes: a protease and a lysin. The protease hydrolyzes casein and haemoglobin and is inactive against bacterial cell walls while the lysin hydrolyzes bacterial cell walls but is inactive on proteins. These enzymes have been separated on hydroxylapatite columns and some of their properties are described. The predatory action of many of the isolates may be explained by the secretion and subsequent action of these two enzymes.

scholarly journals Dramatic performance ofClostridium thermocellumexplained by its wide range of cellulase modalities

2016 ◽  
Vol 2 (2) ◽  
pp. e1501254 ◽  
Author(s):  
Qi Xu ◽  
Michael G. Resch ◽  
Kara Podkaminer ◽  
Shihui Yang ◽  
John O. Baker ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Mode Of Action ◽  
Protein Complexes ◽  
Cellulose Degradation ◽  
Bacterial Cell Wall ◽  
Cellular Functions ◽  
Gene Deletions ◽  
Wide Range ◽  
Biomass Particles

Clostridium thermocellumis the most efficient microorganism for solubilizing lignocellulosic biomass known to date. Its high cellulose digestion capability is attributed to efficient cellulases consisting of both a free-enzyme system and a tethered cellulosomal system wherein carbohydrate active enzymes (CAZymes) are organized by primary and secondary scaffoldin proteins to generate large protein complexes attached to the bacterial cell wall. This study demonstrates thatC. thermocellumalso uses a type of cellulosomal system not bound to the bacterial cell wall, called the “cell-free” cellulosomal system. The cell-free cellulosome complex can be seen as a “long range cellulosome” because it can diffuse away from the cell and degrade polysaccharide substrates remotely from the bacterial cell. The contribution of these two types of cellulosomal systems inC. thermocellumwas elucidated by characterization of mutants with different combinations of scaffoldin gene deletions. The primary scaffoldin, CipA, was found to play the most important role in cellulose degradation byC. thermocellum, whereas the secondary scaffoldins have less important roles. Additionally, the distinct and efficient mode of action of theC. thermocellumexoproteome, wherein the cellulosomes splay or divide biomass particles, changes when either the primary or secondary scaffolds are removed, showing that the intact wild-type cellulosomal system is necessary for this essential mode of action. This new transcriptional and proteomic evidence shows that a functional primary scaffoldin plays a more important role compared to secondary scaffoldins in the proper regulation of CAZyme genes, cellodextrin transport, and other cellular functions.

Comparative ultrastructure of selected oral streptococci: thin-sectioning and freeze-etching studies

1976 ◽  
Vol 22 (4) ◽  
pp. 475-485 ◽  
Author(s):  
Stanley C. Holt ◽  
E. R. Leadbetter
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cytoplasmic Membrane ◽  
Close Association ◽  
Oral Streptococci ◽  
Outermost Layer ◽  
Thin Sectioning ◽  
Freeze Etching ◽  
Comparative Ultrastructure ◽  
Crystalline Array

The ultrastructure of Streptococcus mutans, serotypes a–e, S. sanguis, S. mitis, and S. salivarius HHT, were examined by the techniques of thin-sectioning and freeze-etching. The cell walls varied in width between 15 and 46 nm and were covered with an electron-dense fibrillar or fuzz layer. The cytoplasmic membrane was in close association with numerous mesosomes which were, in turn, either closely associated or in contact with the bacterial chromosome. In freeze-etch replicas, the outermost layer of the cell wall was fibrous, and the cytoplasmic membrane was covered with particles composed of several subunits. Both particle-clusters and particle-free areas occurred on the surfaces of the cytoplasmic membrane, as well as a crystalline array in the ground plasm of the cell.

The outer layer of the cell envelope of Halobacterium halobium

1969 ◽  
Vol 47 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Carolyn L. Marshall ◽  
A. J. Wicken ◽  
A. D. Brown
Keyword(s):  
Cell Wall ◽  
Chemical Analysis ◽  
Outer Layer ◽  
Bacterial Cell ◽  
Cell Walls ◽  
Cell Envelope ◽  
Halobacterium Halobium ◽  
A Cell ◽  
Bacterial Cell Walls

The outer layer of the cell envelope of Halobacterium halobium was isolated after suspending the envelope in either 1 M NaCl or 0.02 M MgCl2. Chemical analysis of the isolated, solubilized outer layer showed it to consist of protein or glycoprotein with about 3% RNA. No free or bound lipid was detected. No cytochromes were present in the outer layer. Components commonly associated with bacterial cell walls were absent.Chemical composition together with the marked instability of the outer layer in a slight ion deficit are not consistent with a function of this layer as a "cell wall" of the organism.

scholarly journals Sham, Sam, And Bacterial Communication

1997 ◽  
Vol 5 (8) ◽  
pp. 8-9
Author(s):  
Lee van Hook
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Cell Walls ◽  
Piezoelectric Crystal ◽  
Acoustic Microscope ◽  
Bacterial Communication ◽  
Bacterial Cell Walls ◽  
Scanning Acoustic Microscope

A scanning acoustic microscope (SAM) - a nanomicrophone using a piezoelectric crystal, may be used to examine bacterial colonies, not just materials specimens to detect phonons and listen to propagating microfractures.Since bacterial cell walls are rigid structures, they undergo mechanical distortions when channels open and dose. This causes them to squeak and pop, each channel having its own sound. Channels and receptor molecules are all of different sizes and shapes, and therefore deform the cell wall in unique ways. This means that each channel makes a unique (if faint) sound when it passes a molecule through itself and this activity can be delected, Transport rates of uptake and excretion for the various compounds car then be calculated trom the intensity of the sounds.

scholarly journals Cytological Aspects of the Mycobiont–Phycobiont Relationship in Lichens

1984 ◽  
Vol 16 (2) ◽  
pp. 111-127 ◽  
Author(s):  
Rosmarie Honegger
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Wall Layer ◽  
Distinct Pattern ◽  
Homogeneous Material ◽  
Wall Surface ◽  
Surface Layers ◽  
Thin Sectioning ◽  
Cytological Features ◽  
Mother Cell Wall

AbstractCytological aspects of the mycobiont-phycobiont contact were investigated in the lichen species Peltigera aphthosa, Cladonia macrophylla, Cladonia caespiticia and Parmelia tiliacea by means of freeze-etch and thin sectioning techniques, and by replication of isolated fragments of myco- and phycobiont cell walls.In the symbiotic state of the mycobionts investigated a thin outermost wall layer with a distinct pattern was observed mainly in the hyphae contacting phycobiont cells and in the upper medullary layer. No comparable structures were noted on the hyphal surface of the cultured mycobionts of the Cladonia and Parmelia species investigated. A distinct rodlet layer was found on the hyphal surface of the mycobiont of Peltigera aphthosa, while mycobionts of Cladonia macrophylla, C. caespiticia and Parmelia tiliacea had a mosaic of small, irregular ridges, each corresponding in its size to a bundle of rodlets on the outermost wall layer. Comparable surface layers have been described in aerial hyphae of a great number of non-lichenized fungi.The rodlet layer of the mycobiont wall surface of Peltigera aphthosa adheres tightly to the outermost layer of the sporopollenin-containing cell wall of the Coccomyxa phycobiont. Mature trebouxioid phycobiont cells of the Cladonia and Parmelia species investigated in the symbiotic state had an outermost wall layer which was structurally indistinguishable from the tessellated surface layer of the mycobiont cells. A rodlet pattern was detected in the outermost wall layer of Trebouxia autospores still surrounded by the cellulosic mother cell wall. In mature Trebouxia cells the bundles of rodlets became increasingly covered by a homogeneous material, and thus attained the same tessellated pattern which was observed on the mycobiont wall surface. No comparable structures were found on the wall surface after culturing the Trebouxia phycobionts axenically in liquid media. Confluence of the tessellated surface layers of fungal and algal origin was noted at the contact sites of growing hyphal tips and young Trebouxia cells.The possible correlations between these cytological features and published immunological data on the cell surface of cultured and symbiotic lichen myco- and phycobionts are discussed.

Structure and assembly of bacterial surface layers composed of regular arrays of subunits

1974 ◽  
Vol 268 (891) ◽  
pp. 147-153 ◽  
Keyword(s):  
Self Assembly ◽  
Cell Walls ◽  
Surface Layers ◽  
Intact Cells ◽  
Bacterial Surface ◽  
Outer Membranes ◽  
And Function ◽  
Isolated Cell ◽  
Regular Arrays ◽  
Intact Bacterium

Regular arrays of subunits are observed on the surfaces of many bacteria, and the structure and function of such an array are being examined in a study of the Gram-negative bacterium Acinetobacter strain MJT/F5/199A. The subunits are on the surface of the outer membrane and are visible in electron micrographs of freeze-etched intact cells and of negatively stained preparations of isolated cell walls and outer membranes. The surface subunits can be detached from the membrane by various treatments and will then reassemble spontaneously to form the same regular pattern as that seen on the intact bacterium. The results of studies of the properties of the self-assembly system are described and its relevance to the formation of surface layers composed of regular arrays of subunits in intact bacteria discussed.

scholarly journals SaccuFlow: High-throughput Analysis Platform to Investigate Bacterial Cell Wall Interactions

2021 ◽  
Author(s):  
Alexis J Apostolos ◽  
Noel J Ferraro ◽  
Brianna E Dalesandro ◽  
Marcos Pires
Keyword(s):  
Cell Wall ◽  
High Throughput ◽  
Bacterial Cell ◽  
Cell Walls ◽  
Turgor Pressure ◽  
Principal Component ◽  
Bacterial Cells ◽  
High Throughput Analysis ◽  
Peptidoglycan Biosynthesis ◽  
Analysis Platform

Bacterial cell walls are formidable barriers that protect bacterial cells against external insults and oppose internal turgor pressure. While cell wall composition is variable across species, peptidoglycan is the principal component of all cell walls. Peptidoglycan is a mesh-like scaffold composed of crosslinked strands that can be heavily decorated with anchored proteins. The biosynthesis and remodeling of peptidoglycan must be tightly regulated by cells because disruption to this biomacromolecule is lethal. This essentiality is exploited by the human innate immune system in resisting colonization and by a number of clinically relevant antibiotics that target peptidoglycan biosynthesis. Evaluation of molecules or proteins that interact with peptidoglycan can be a complicated and, typically, qualitative effort. We have developed a novel assay platform (SaccuFlow) that preserves the native structure of bacterial peptidoglycan and is compatible with high-throughput flow cytometry analysis. We show that the assay is facile and versatile as demonstrated by its compatibility with sacculi from Gram-positive bacteria, Gram-negative bacteria, and mycobacteria. Finally, we highlight the utility of this assay to assess the activity of sortase from Staphylococcus aureus against potential anti-virulence agents.

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