Why does the presence of grease or dirt

What do Amoebas use for movement. How are algae different from plants. How do cells control osmosis. What is cytoplasm. Where is ATP often produced. What causes water to be a polar molecule. Q: Why does the presence of grease or dirt on a slide result in a poor smear preparation?

Write your answer Related questions. Why do you think the presence of grease or dirt on a glass slide will result i a poor smear preparation? Why do you think the presence of grease or dirt on a glass slide will result in a poor smear preparation? Is presence of grease or dirt on a glass slide going to result in poor smear preparation?

Can you use slide grease for tuba valves? How do you use slide grease on a trumpet? What care mustyou take when using a slide? How do you grease the back disc brakes on a Honda Accord they are vibrating? Can you put valve oil on a tuning slide? Can Vaseline be used for slide grease? Why must slides used in smear preparations be grease free? What is a cork grease substitute? What is the purpose of heat fixation preparation of a smear on a slide?

Can trombone slide oil be used for trumpet valves? Can you use slide grease on a clarinet? What are the importance of text object in slide preparation? Why is dialectric grease used on brake slide pins? What are the importance of media object in slide preparation?

How do you make oven racks slide easier? What are three common lubricants? What is the purpose of adding iodine solution to the onion slide preparation? Why will a greasy or dirty slide reult in poor slide preparation? What is a wet mount slide? How do you get a stuck trumpet slider off? Can cork grease be used on brass instruments? The large iodine-crystal violet complex is retained within the cell walls of gram positive cells because of the molecular structure of the many layers of peptidoglycan in the cell wall.

There are lots of cross-linked teichoic acids and the iodine-dye complex cannot physically get out. There is also less lipid in the membrane and the decolorizing agent cannot get to it as well.

Gram negative cells have an outer membrane and only one layer of peptidoglycan, with more lipid. The crystal violet dye is easily washed out. The accuracy of the Gram stain is dependent on the integrity of the bacterial cell wall. There are a variety of things that can influence the cell wall integrity; old cells i. Under these conditions, gram positive cells will come out as gram-negative.

If you de-colorize too long, Gram-positive cells will look like Gram-negative cells. Conversely, if you do not decolorize enough, Gram-negatives will look like Gram-positives.

The only way you can trust your results it to always run a known Gram-positive and a known Gram-negative on the same slide. If they stain as predicted you can be pretty sure the result of your unknown sample is reliable.

The Gram staining takes practice to get right. Do not expect to get a good Gram stain on your first try. It is a good idea to hold your slide with a clothespin; your gloves will get pretty psychedelic as will everything you touch! The Congo Red Capsule stain is a modification of the nigrosin negative stain you may have done previously. The bacteria take up the congo red dye and the background is stained then with acid fuchsin dye.

The capsule or slime layers, highly hydrated polymers, exclude both dyes. The background will appear blue, the bacterial cells will appear pink, and the clear halos are the capsules. Clinically, the capsules of some highly pathogenic bacteria i. The bacteria are suspended in the antisera and then mixed with methlyene blue. In the antisera staining procedure, the bacteria will appear blue surrounded by a clear halo and then surrounded by a thin blue line where the antisera have attached to the capsule.

Endospore formation is characteristic of Clostridum and Bacillus spp. The ability to concentrate and coat their protoplasm allows them to survive the adverse environmental conditions they experience in their soil habitat.

This also allows the spores to resist staining. Endospores are typically highly refractile, light striking them is deflected. Many Bacillus species have inclusion bodies that are highly refractile. These inclusion bodies may look like endospores with regular staining.

The presence of endospores must be confirmed with endospore specific stains. The presence, and characteristic shape and position of endospores require special procedures to permeate the endospore coat.

Most endospore stains involve heating the slides while keeping them continually moist with the dye. While quicker, it produces volatile chemicals and is just a big mess. The same results can be obtained by letting the dye sit on the slide for 30 minutes.

It is a good idea to start this slide first and work on another stain while you are waiting for the dye to permeate the endospore. You will be using a Bacillus species for the endospore stain. The shape and position of B. Bacillus does not start forming spores until it runs out of food. If the cultures are too young, you will mostly see just the pink rods of the bacteria. If the cultures are too old, you will mostly see just the small green ovals of the endospores.

Ideally, you should see the green oval bodies of the endospore surrounded by the pink vegetative bacterial cell. Select a sample from the middle of a colony with the straight inoculating needle for the best results. The edge of the colony is still actively growing and will have few endospores.

Microbiology Resource Center. There are two important things to consider when preparing a slide for staining: The bacteria must be evenly and lightly dispersed. If there are too many bacteria on the slide they will form a big glob and you will not be able to see the morphology of the individual cells.

Large blobs of cells also do not stain properly and could yield erroneous results from the improper staining. The bacteria need to be firmly attached to the slide so they are not washed off during the staining procedures. All procedures that attach the bacteria to the slide result in some morphological changes.

The cells typically shrink in size and will exhibit some changes in shape and extra-cellular matrixes. Materials Clean glass slides Inoculating loops or needles Sterile water Marking pen Assorted broth and plate cultures Safety Considerations Be careful of aerosols when transferring bacteria from your loop to the slide. General Considerations You are striving for a light suspension of cells that will leave a faint cloudy deposit on your slide.

Smear from Broth Broth cultures are usually easier to work with because the cells are already diluted in the broth. Label your slide. Overheating the smear during heat-fixing process can distort the form and structure of the cells. Beta-lactam antibiotics form the backbone of treatment for Gram-negative pneumonia in mechanically ventilated patients in the intensive care unit.

The most common pathogens are gram-negative bacilli and Staphylococcus aureus; antibiotic-resistant organisms are an important concern.

Symptoms and signs include malaise, fever, chills, rigor, cough, dyspnea, and chest pain. The best initial antibiotic choice is thought to be a macrolide. Macrolides provide the best coverage for the most likely organisms in community-acquired bacterial pneumonia CAP.