Role Of Lec A / Gb-3 In Engulfment Of Bacteria

Phospholipids make up most of the cell membrane, in a phospholipid bilayer. Phospholipid molecules form two layers, with the hydrophilic (water loving) head facing the extracellular fluid and the cytosol (intracellular) fluid, and the hydrophobic (not water loving) tails facing one another. The cell membrane is constructed in such a way that it is semipermeable, and allows oxygen, CO2 and lipid soluble molecules through easily, while other molecules like glucose, amino acids, water, and ions cannot pass through quite as easily. That is the meaning behind the chant “some things can pass, others cannot!”.

The bacterial cell wall is comprised of glycan strands of repeating disaccharide derivatives N-acetylglucosamine acid and N-acetylmuramic acid attached to a cross-link of amino acids, including L-alanine, D-alanine, D-glutamic acid, and either L-lysine or diaminopimelic acid (DAP). This mesh-like structure is called the peptidoglycan. It serves as an exoskeleton for the bacterial cell and is critical to bacterial cell’s ability to survive environmental conditions [1]. In gram-positive bacteria, the peptidoglycan is the cell’s outermost structure, while in the gram-negative bacteria, this structure is sandwiched between an outer membrane and the inner membrane called the periplasm.

When glucose carriers in the membrane were set to 500, the glucose transport rate for 2.00 mM of glucose was .0008 mM/min. Equilibrium was reached at 43 minutes. At 700 glucose carriers the rate was .0010 mM , and equilibrium was reached at 33 minutes. When the glucose carriers was set at 900 the rate was .012 mM/min, and equilibrium was reached at 27 minutes. After changing the glucose concentration to 8.0 mM, the glucose transport rate with 500 carrier proteins was .0023 mM/min, and equilibrium was reached at 58 minutes. With the simulation set at 700 carrier proteins the rate was .0031mM/min, and equilibrium was reached at 43 minutes. When the simulation was done with 900 carrier proteins the glucose transport rate was .0038, and equilibrium was reached at 35 minutes.

The phospholipid bilayer that makes up the cell membrane is largely made up of a mixture of lipids and proteins. The lipids give the structure the right level of flexibility, while the proteins help to watch and control the cell’s “chemical climate” and also with molecule movement across the bilayer. This means that the proteins, especially the ones that bridge the whole membrane, can allow passage of say electrolytes and non-lipid substances.

Introduction: The biological membranes are composed of phospholipid bilayers, each phospholipid with hydrophilic heads and hydrophobic tails, and proteins. This arrangement of the proteins and lipids produces a selectively permeable membrane. Many kinds of molecules surround or are contained within

The Gram-positive cell wall is composed of peptidoglycans, a thick layer of protein-sugar complexes taking up 60-90% of their cell wall. Peptidoglycan is composed of two glucose derivatives, N-acetylmuramic acid and N-acetylglucosamine alternated and cross-linked by tetrapeptides that is composed of L-alanine, D-glutamine, L-lysine

Gram negative and gram positive bacteria differ from each other in many ways especially in the composition and size of their cell walls. Unlike Gram-positive bacteria, Gram-negative bacteria have a thin peptidoglycan layer surround by an outer membrane. This outer membrane contains many proteins one of them being lipopolysaccharides (LPS), which contributes to the bacteria’s negative charge. One part of this protein is a lipid, called Lipid A, which is considered an endotoxin because this lipid triggers an immune response stimulating fever

Our results show no growth whatsoever in those plates containing Ampicillin; this indicates that we encounter an error during our experiment. The agar plate's outcomes and bioluminescent response done by the bacterium that had the plasmid, it can be presumed due to scientific analysis that Escherichia coli is impervious to ampicillin and the plasmid combines itself with the DNA of Escherichia coli according to other experiments and based on science itself. We can predict that the impact of the bioluminescence in the cells of the microorganisms that is infested unmistakably gives affirmation that the plasmid infuses with Escherichia coli's DNA, guarding the cells that changed from dying, viably creating a gainful situation for the bacterial organisms. Since Escherichia coli is a negative prokaryotic call, it is within the phospholipid bilayer and on top of this is a peptide glycan

Carson, V. (2013). Microbiology Lab (1st ed.). Department of Cell Biology, Microbiology & Molecular Biology. University of South Florida.

Gram negative bacteria have a thin layer of peptidoglycan. More complex layer that provides cover that is anchored to the lipoprotein molecules of the peptidoglycan layer. This membrane contains porin, which allows penetration of only small molecules. This serves as a defense mechanism of large molecules such as

Summary of Lipid Dynamics Project. Lipid membranes are highly dynamic. Lipid membranes are highly dynamic. In 1972, Singer and Nicholson introduced the mosaic bilayer model, which suggests that membranes are two dimensional homogeneous liquid. Nowadays with a better understanding of the dynamics occurring at the molecular level of membranes, we are aware of their transverse and lateral heterogeneities. Studies suggest the existence of the so called lipid rafts. These are sub-domains with unique lipid and protein composition, in general with high concentrations of cholesterol and glycosphingolipids. They are believed to play an important role on cell

After entry, the bacteria are trapped in a single membrane vacuole known as the phagosome. Lm must escape from the phagosome into the cytosol by the action of the secreted pore-forming toxin, Listeriolysin O (LLO) which is encoded by hly (Portnoy et al., 2002). Getting access to the cytosol is necessary for a successful infection and failure to escape from the phagosome results in the elimination of the bacteria from tissues (Le Monnier et al., 2007). LLO belongs to a family of cholesterol- dependent cytolysins (CDCs) which are secreted as a soluble monomers and characterized by their ability to bind to the cholesterol of host membranes, oligomerize, and form a large pores (Schnupf et al., 2007). Bacterial membranes lacking sterols are therefore not affected by the action of these toxins.

Consequently, membrane permeability gets distorted, due to progressive release of lipopolysaccharide molecules and membrane proteins.

Pathogenic L. monocytogenes go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. The bacterium is first phagocytosed by these cells and secretes a pore-forming toxin called listeriolysin, which allows the bacterium to escape from the phagosome. All virulent strains of L. monocytogenes synthesize and secrete listeriolysin. Phospholipase A and B are other virulence factors that facilitate escape of L. monocytogenes from the phagosome. Once out of the phagosome L. monocytogenes is capable of rapid division in the cytoplasm, evading the immune response and moving throughout the cytoplasm from cell to cell. L. monocytogenes is well known for its ability to propel itself like a rocket through the cell cytoplasm. This is the result of the bacterium’s ability to polymerize actin filaments at its tail end. Actin is arranged in subunits to form microfilaments that are capable of directing cell movement. L. monocytogenes accomplishes cell motility through a virulence factor called ActA that takes advantage of normal actin polymerization going on in the cell. The ActA protein shares sequence homology with a protein called WASP that is found in virtually all eukaryotic cells. WASP is responsible for recognizing and

In all areas of biology, it is easy to see that structure is related to function. This statement holds true in microbiology as well, the study of microorganisms, including bacteria. One characterizing feature of bacteria is the cell wall, which can generally (although not in all situations) be categorized into one of two categories: either Gram positive or Gram negative. Gram positive bacteria’s cell walls are composed of a large peptidoglycan layer (up to 90% of their cell wall). Within this large peptidoglycan layer, one can find techoic acids, which contribute to the maintenance of cell wall structure, and lipotechoic acids, which attach to membrane lipids. Gram positive bacteria that act as pathogens can also potentially release exotoxins, which can have very dangerous effects on humans. Gram negative bacteria, on the other hand, have a very small layer of peptidoglycan in their cell wall, which is surrounded by an outer membrane. Within the outer membrane, one can find the lipopolysaccharide layer, which is one of the most distinguishing factors of Gram-negative bacteria. It is important to note that Gram negative bacteria fail to possess techoic