P 1.2 Gram-Positives vs. Gram-Negatives

Endospore stain

Endospores are structures produced within certain bacterial cells that allow them to survive harsh conditions. Gram staining alone cannot be used to visualize endospores, which appear clear when Gram-stained cells are viewed. Endospore staining uses two stains to differentiate endospores from the rest of the cell. The Schaeffer-Fulton method (the most commonly used endospore-staining technique) uses heat to push the primary stain (malachite green) into the endospore. Washing with water decolorizes the cell, but the endospore retains the green stain. The cell is then counterstained pink with safranin. The resulting image reveals the shape and location of endospores, if they are present. The green endospores will appear either within the pink vegetative cells or as separate from the pink cells altogether. If no endospores are present, then only the pink vegetative cells will be visible

"G" sugars

NAG functional groups that are added to the glycose

"M" sugars

NAM functional groups that are added to the glycose

2. Describe the structure of a peptidoglycan cell wall in bacteria? What are its 2 main parts? (the word "peptidoglycan" gives you a hint)

Peptidoglycan is made of chains of alternating molecules called N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). When these two molecules are covalently bonded together, it is called a glycan chain. Peptides are short chains of amino acid monomers linked by peptide bonds. (short proteins)

Why each step?

Violet crystals to add color, they get stuck into membranes. Iodine helps stick the die to the membranes.(mordant, that is better in positive gram cause it is thicker.) Alcohol removes any not deepset crystals, so negative gram would be clear. Safranin- doesn't change the color of gram positive but makes the now colorless gram negative to red.

Streptococcus

Streptococcus is a genus of gram-positive coccus (plural cocci), or spherical bacteria, that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Firmicutes.

5. The Gram stain is an important tool in identifying bacterial infections from patient samples. Perform a quick internet search and determine when Hans Christian Gram developed the Gram stain. Was it before or after the restoration of the gospel by Joseph Smith?

The Gram staining method, named after the Danish bacteriologist who originally devised it in 1882e

Staphylococcus

a genus of gram-positive bacteria that are potential pathogens, causing local lesions and serious opportunistic infections

Phospholipid

a lipid that contains phosphorus and that is a structural component in cell membranes

Bacillus

a rod-shaped bacterium

Coccus

any spherical or roughly spherical bacterium

staphylo

bunch of grapes

Lipid bi-layer membrane

lipid part of the phospolipid bi layer. The lipid bilayer is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells

outer membrane of gram negative bacteria

made of a lipid bilayer composed of lipopolysaccharides called endotoxins. serves as a barrier to the passage of most molecules and only allow certain molecules to pass through the membrane.

Spirillum

spiral shaped bacteria

strep

twisted chain

Gram Stain

which have thinner membranes.

Gram Negative

which have thinner membranes. Have an outer membrane.

What is needed to succed?

Come to class and take good notes. Complete all preparation guides. consistent study seek for understanding pray for help.

7. What is Lipopolysaccharide (LPS)? Is it found in Gram-Positive or Negative bacteria? Where is it found in bacteria?

Gram-negative bacteria, outer membrane.

Diplococcus

A diplococcus is a round bacterium that typically occurs in the form of two joined cells

8. What is the acid-fast stain? What types of bacteria is this used to identify? What disease does this bacterium cause?

Acid-fast staining is another commonly used, differential staining technique that can be an important diagnostic tool. An acid-fast stain is able to differentiate two types of gram-positive cells: those that have waxy mycolic acids in their cell walls, and those that do not. Two different methods for acid-fast staining are the Ziehl-Neelsen technique and the Kinyoun technique. Both use carbolfuchsin as the primary stain. The waxy, acid-fast cells retain the carbolfuchsin even after a decolorizing agent (an acid-alcohol solution) is applied. A secondary counterstain, methylene blue, is then applied, which renders non-acid-fast cells blue. The fundamental difference between the two carbolfuchsin-based methods is whether heat is used during the primary staining process. The Ziehl-Neelsen method uses heat to infuse the carbolfuchsin into the acid-fast cells, whereas the Kinyoun method does not use heat. Both techniques are important diagnostic tools because a number of specific diseases are caused by acid-fast bacteria (AFB). If AFB are present in a tissue sample, their red or pink color can be seen clearly against the blue background of the surrounding tissue cells (Figure).

1. Describe the function of the "phospholipid bi-layer membrane" found in all living cells.

Barrier and pathways for various substances across membranes. - cell wall keeps the plasma membrane from rupturing from osmosis. Antibiotics disrupts cell walls, so they break and die.

6. Describe the procedure used in the Gram stain. (List the steps and chemicals used in each step). chapter 3 slides p.12 or VIAS

Gram Staining The Gram stain procedure is a differential staining procedure that involves multiple steps. It was developed by Danish microbiologist Hans Christian Gram in 1884 as an effective method to distinguish between bacteria with different types of cell walls, and even today it remains one of the most frequently used staining techniques. The steps of the Gram stain procedure are listed below and illustrated in Figure. First, crystal violet-, a primary stain, is applied to a heat-fixed smear, giving all of the cells a purple color. Next, Gram's iodine, a mordant, is added. A mordant is a substance used to set or stabilize stains or dyes; in this case, Gram's iodine acts like a trapping agent that complexes with the crystal violet, making the crystal violet-iodine complex clump and stay contained in thick layers of peptidoglycan in the cell walls. Next, a decolorizing agent is added, usually ethanol or an acetone/ethanol solution. Cells that have thick peptidoglycan layers in their cell walls are much less affected by the decolorizing agent; they generally retain the crystal violet dye and remain purple. However, the decolorizing agent more easily washes the dye out of cells with thinner peptidoglycan layers, making them again colorless. Finally, a secondary counterstain, usually safranin, is added. This stains the decolorized cells pink and is less noticeable in the cells that still contain the crystal violet dye.The purple, crystal-violet stained cells are referred to as gram-positive cells, while the red, safranin-dyed cells are gram-negative

What is the difference between gram negative and gram negative?

Gram negative and positive is the same inside. Gram positive cell wall peptidoglycan thicker (Lipteichoic uses acid to give structure to wall and lipid locks into phospolipid membrane.). Gram positive have thin wall and has lipopolysaccarides(is toxic and gives support).

Gram Positive

Gram positive bacteria have thick cell membranes, and they're a huge group that includes species that live individually like staphlococcus and streptococcus, as well as some colonial bacteria that are responsible for diseases like leprosy and tuberculosis. 5-7 layers of peptidoglycan.

Gram staining procedure is used so much because?

If someone comes into hospital sick taking a sample,

Differential stain

In contrast, differential staining distinguishes organisms based on their interactions with multiple stains. In other words, two organisms in a differentially stained sample may appear to be different colors. Differential staining techniques commonly used in clinical settings include Gram staining, acid-fast staining, endospore staining, flagella staining, and capsule staining.

Simple stain

In simple staining, a single dye is used to emphasize particular structures in the specimen. A simple stain will generally make all of the organisms in a sample appear to be the same color, even if the sample contains more than one type of organism