Comparison of the cell surface barrier and enzymatic modification system inBrevibacterium flavum andB. lactofermentum

2005 ◽  
Vol 10 (3) ◽  
pp. 225-229
Author(s):  
Ki-Hyo Jang ◽  
Margaret L. Britz
Keyword(s):  
Cell Surface ◽  
Surface Barrier ◽  
Enzymatic Modification ◽  
Modification System

scholarly journals One-Step Enzymatic Modification of the Cell Surface Redirects Cellular Cytotoxicity and Parasite Tropism

2014 ◽  
Vol 10 (2) ◽  
pp. 460-465 ◽  
Author(s):  
Lee Kim Swee ◽  
Sebastian Lourido ◽  
George W. Bell ◽  
Jessica R. Ingram ◽  
Hidde L. Ploegh
Keyword(s):  
Cell Surface ◽  
Cellular Cytotoxicity ◽  
Enzymatic Modification ◽  
One Step

MUCI, glycans and the cell-surface barrier to embryo implantation

2001 ◽  
Vol 29 (2) ◽  
pp. 153-156 ◽  
Author(s):  
J. D. Aplin ◽  
M. Meseguer ◽  
C. Simon ◽  
M. E. Ortíz ◽  
H. Croxatto ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cells ◽  
Cell Surface ◽  
Embryo Implantation ◽  
Human Embryos ◽  
Surface Barrier ◽  
Epithelial Surface ◽  
Epithelial Monolayers ◽  
Maternal Rejection ◽  
Normal Expression

As it approaches the maternal surface, the attaching embryo encounters the epithelial glycocalyx, which contains the mucin, MUC1. A high density of MUC1 at the cell surface can inhibit cell adhesion. This raises the possibility of the existence of a uterine barrier to implantation that might allow maternal rejection of poorer quality embryos. To investigate the mechanism of implantation, human embryos were incubated with endometrial epithelial monolayers. Hatched blastocysts were found to attach readily to the epithelial surface. MUC1 was lost from epithelial cells beneath and near to the attached embryo, while normal expression persisted in neighbouring cells.

scholarly journals The Wzi outer membrane protein mediates assembly of a tight capsular polysaccharide layer on the Acinetobacter baumannii cell surface

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jacob Tickner ◽  
Sophia Hawas ◽  
Makrina Totsika ◽  
Johanna J. Kenyon
Keyword(s):  
Membrane Protein ◽  
Cell Surface ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Capsular Polysaccharide ◽  
Bacterial Pathogen ◽  
Surface Barrier ◽  
Transmission Electron ◽  
Fold Reduction

AbstractIdentification of novel therapeutic targets is required for developing alternate strategies to treat infections caused by the extensively drug-resistant bacterial pathogen, Acinetobacter baumannii. As capsular polysaccharide (CPS) is a prime virulence determinant required for evasion of host immune defenses, understanding the pathways for synthesis and assembly of this discrete cell-surface barrier is important. In this study, we assess cell-bound and cell-free CPS material from A. baumannii AB5075 wildtype and transposon library mutants and demonstrate that the Wzi outer membrane protein is required for the proper assembly of the CPS layer on the cell surface. Loss of Wzi resulted in an estimated 4.4-fold reduction in cell-associated CPS with a reciprocal increase in CPS material shed in the extracellular surrounds. Transmission electron microscopy revealed a disrupted CPS layer with sparse patches of CPS on the external face of the outer membrane when Wzi function was lost. However, this genotype did not have a significant effect on biofilm formation. Genetic analysis demonstrated that the wzi gene is ubiquitous in the species, though the nucleotide sequences were surprisingly diverse. Though divergence was not concomitant with variation at the CPS biosynthesis K locus, an association between wzi type and the first sugar of the CPS representing the base of the structure most likely to interact with Wzi was observed.

Protein cell-surface display through in situ enzymatic modification of proteins with a poly(Ethylene glycol)-lipid

2013 ◽  
Vol 110 (10) ◽  
pp. 2785-2789 ◽  
Author(s):  
Urara Tomita ◽  
Satoshi Yamaguchi ◽  
Yasukazu Maeda ◽  
Kazuki Chujo ◽  
Kosuke Minamihata ◽  
...  
Keyword(s):  
Cell Surface ◽  
Ethylene Glycol ◽  
Surface Display ◽  
Cell Surface Display ◽  
Enzymatic Modification ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
Protein Cell

scholarly journals Technologies for Proteome-Wide Discovery of Extracellular Host-Pathogen Interactions

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Nadia Martinez-Martin
Keyword(s):  
Cell Surface ◽  
Protein Interactions ◽  
Extracellular Protein ◽  
Interaction Networks ◽  
Productive Infection ◽  
Surface Barrier ◽  
Host Pathogen Interaction ◽  
Genome Wide ◽  
Host Pathogen ◽  
Extracellular Molecules

Pathogens have evolved unique mechanisms to breach the cell surface barrier and manipulate the host immune response to establish a productive infection. Proteins exposed to the extracellular environment, both cell surface-expressed receptors and secreted proteins, are essential targets for initial invasion and play key roles in pathogen recognition and subsequent immunoregulatory processes. The identification of the host and pathogen extracellular molecules and their interaction networks is fundamental to understanding tissue tropism and pathogenesis and to inform the development of therapeutic strategies. Nevertheless, the characterization of the proteins that function in the host-pathogen interface has been challenging, largely due to the technical challenges associated with detection of extracellular protein interactions. This review discusses available technologies for the high throughput study of extracellular protein interactions between pathogens and their hosts, with a focus on mammalian viruses and bacteria. Emerging work illustrates a rich landscape for extracellular host-pathogen interaction and points towards the evolution of multifunctional pathogen-encoded proteins. Further development and application of technologies for genome-wide identification of extracellular protein interactions will be important in deciphering functional host-pathogen interaction networks, laying the foundation for development of novel therapeutics.

Influence of Calcium Ions on the Plant Cell Surface: Membrane Fusions and Conformational Changes

1974 ◽  
Vol 32 ◽  
pp. 154-155
Author(s):  
D. James Morré ◽  
Charles E. Bracker ◽  
William J. VanDerWoude
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Conformational Changes ◽  
Calcium Ions ◽  
Surface Membrane ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Ultrastructural Evidence ◽  
Glycine Max L ◽  
Wall Extensibility

Calcium ions in the concentration range 5-100 mM inhibit auxin-induced cell elongation and wall extensibility of plant stems. Inhibition of wall extensibility requires that the tissue be living; growth inhibition cannot be explained on the basis of cross-linking of carboxyl groups of cell wall uronides by calcium ions. In this study, ultrastructural evidence was sought for an interaction of calcium ions with some component other than the wall at the cell surface of soybean (Glycine max (L.) Merr.) hypocotyls.

Morphological Changes in the Rat Granulosa Cell Surface During Differentiation Induced by Estradiol and Gonadotropins

1977 ◽  
Vol 35 ◽  
pp. 484-485
Author(s):  
P. Bagavandoss ◽  
JoAnne S. Richards ◽  
A. Rees Midgley
Keyword(s):  
Cell Surface ◽  
Granulosa Cell ◽  
Morphological Changes ◽  
Follicular Development ◽  
Female Rats ◽  
Functional Changes ◽  
Group 4 ◽  
Group 3 ◽  
Group 5 ◽  
Group 2

During follicular development in the mammalian ovary, several functional changes occur in the granulosa cells in response to steroid hormones and gonadotropins (1,2). In particular, marked changes in the content of membrane-associated receptors for the gonadotropins have been observed (1).We report here scanning electron microscope observations of morphological changes that occur on the granulosa cell surface in response to the administration of estradiol, human follicle stimulating hormone (hFSH), and human chorionic gonadotropin (hCG).Immature female rats that were hypophysectcmized on day 24 of age were treated in the following manner. Group 1: control groups were injected once a day with 0.1 ml phosphate buffered saline (PBS) for 3 days; group 2: estradiol (1.5 mg/0.2 ml propylene glycol) once a day for 3 days; group 3: estradiol for 3 days followed by 2 days of hFSH (1 μg/0.1 ml) twice daily, group 4: same as in group 3; group 5: same as in group 3 with a final injection of hCG (5 IU/0.1 ml) on the fifth day.

Data Acquisition and Handling Unit for a Quantitative Use of Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 232-233 ◽  
Author(s):  
P. Trebbia ◽  
P. Ballongue ◽  
C. Colliex
Keyword(s):  
Electron Microscope ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Single Channel ◽  
Detection System ◽  
Surface Barrier ◽  
Solid State Detector ◽  
Electrostatic Mirror ◽  
Electron Energy Loss

An effective use of electron energy loss spectroscopy for chemical characterization of selected areas in the electron microscope can only be achieved with the development of quantitative measurements capabilities.The experimental assembly, which is sketched in Fig.l, has therefore been carried out. It comprises four main elements.The analytical transmission electron microscope is a conventional microscope fitted with a Castaing and Henry dispersive unit (magnetic prism and electrostatic mirror). Recent modifications include the improvement of the vacuum in the specimen chamber (below 10-6 torr) and the adaptation of a new electrostatic mirror.The detection system, similar to the one described by Hermann et al (1), is located in a separate chamber below the fluorescent screen which visualizes the energy loss spectrum. Variable apertures select the electrons, which have lost an energy AE within an energy window smaller than 1 eV, in front of a surface barrier solid state detector RTC BPY 52 100 S.Q. The saw tooth signal delivered by a charge sensitive preamplifier (decay time of 5.10-5 S) is amplified, shaped into a gaussian profile through an active filter and counted by a single channel analyser.

Surface Structure of Nucleated Animal Cells: Carbon Replicas

1967 ◽  
Vol 25 ◽  
pp. 120-121
Author(s):  
Robert M. Glaeser ◽  
Thea B. Scott
Keyword(s):  
Cell Surface ◽  
Surface Structure ◽  
Particle Diameter ◽  
Cellular Functions ◽  
Animal Cells ◽  
Replica Technique ◽  
Carbon Replica ◽  
Characteristic Particle ◽  
Cell Surface Structure ◽  
Carbon Replicas

The carbon-replica technique can be used to obtain information about cell-surface structure that cannot ordinarily be obtained by thin-section techniques. Mammalian erythrocytes have been studied by the replica technique and they appear to be characterized by a pebbly or “plaqued“ surface texture. The characteristic “particle” diameter is about 200 Å to 400 Å. We have now extended our observations on cell-surface structure to chicken and frog erythrocytes, which possess a broad range of cellular functions, and to normal rat lymphocytes and mouse ascites tumor cells, which are capable of cell division. In these experiments fresh cells were washed in Eagle's Minimum Essential Medium Salt Solution (for suspension cultures) and one volume of a 10% cell suspension was added to one volume of 2% OsO4 or 5% gluteraldehyde in 0.067 M phosphate buffer, pH 7.3. Carbon replicas were obtained by a technique similar to that employed by Glaeser et al. Figure 1 shows an electron micrograph of a carbon replica made from a chicken erythrocyte, and Figure 2 shows an enlarged portion of the same cell.

Sign in / Sign up

Export Citation Format

Share Document