Why Does This Exercise Call For An Older (5-day) Culture Of Bacillus


why does this exercise call for an older culture of bacillus

What causes the gram stain to behave in the manner that it does? … What is the reason that an older (5-day) culture of Bacillus species is required for the endospore stain? Because older bacteria are more nutritionally stressed, there will be a higher number of endospores present. Which characteristics of the organism do a positive result for the spore stain reveal about it? A dormant, tough, and non-reproductive structure formed by certain bacteria belonging to the phylum Firmicutes, an endospore is a structure that does not reproduce.

Endospores allow bacteria to remain inactive for long periods of time, perhaps even centuries.

Why do you need to use older cultures of Bacillus for Endospore staining?

Endospore staining is referred to as a structural stain since it is used to draw attention to a specific structure within a cell. … Most techniques recommend using cultures that are 18-36 hours old in order to increase the likelihood that spore formers will be discovered. As cultures age, they become more nutrient deprived, which results in sporulation.

Why was a 48 hour culture of B subtilis used rather than a fresh culture?

Why is a 48-hour culture necessary for an endospore stain to be effective? Endospores are formed as a result of environmental stress. You will be able to tell if the bacterium is starving if you wait 48 hours.

How might the age of the culture affect the results of the endospore stain?

What effect does the age of the culture have on the findings of a spore stain? Old cultures contain a higher concentration of spores, and bacteria generate more endospores as they become older.

What is the relationship between age of a culture and number of endospores?

Which relationship exists between the age of a culture and the quantity of endospores present? The younger cultures included more vegetative cells, whereas the older cultures contained endospores. The more advanced the age, the more likely it is that the vegetative cell will die and release the spore. – Counterstain for one minute with safranin stain.

Why is an old culture necessary for finding spores?

Bacterial bodies and flagella will discolor the surface of the Material. Why was it required to utilize an old Bacillus culture for the spore stain, rather than a new one, in this experiment? It is because endospores are forming in an older culture that the needed nutrients are not accessible that the endospores are being created. 2.

How does the culture affect the results of an Endospore stain quizlet?

What role does culture have in the outcome of an endospore staining experiment? For example, if the culture is kept in a hostile environment, there will be more viable spores than viable cells. The same is true in the other direction. What color are endospores after they have been stained with a Gram stain?

Why does the Endospore stain exercise call for an older 48 hour or 5 day culture of Bacillus?

What causes the gram stain to behave in the manner that it does? … What is the reason that an older (5-day) culture of Bacillus species is required for the endospore stain? Because older bacteria are under more nutritional stress, there will be a higher concentration of endospores in the environment. Which characteristics of the organism do a positive result for the spore stain reveal about it?

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What is the function of the Z ring in binary fission?

What is the role of the Z ring in the process of binary fission?

It is in charge of the replication of DNA. It contracts at the septum, forming a contractile ring.

Why would older gram positive cultures stain incorrectly?

What causes gram-positive cultures that are more than a decade old to stain incorrectly? When gram-positive cultures become older, they lose their capacity to maintain the crystal-violet iodine complexes and provide misleading gram-negative readings. What component of a bacterial cell wall allows an organism to be classified as gram positive?. Is it possible that the culture smear was not heat fixed?

How might an old culture affect the results of a Gram stain?

Cells that have burst or died in older cultures are more prevalent. Even though the bacteria in the culture are Gram positive, cells from old cultures may stain Gram negative. To yet, the specific mechanism of the Gram stain response has not been determined in detail.

How does the age of the culture affect the results of the Gram stain for gram-positive bacteria?

The age of a culture has an effect on the gram stain response, but how? a.Old cultures have the potential to change to gram-variable or gram-negative, resulting in incorrect findings. If done for an excessive amount of time, gram-positive can seem gram-negative, and if done for an insufficient amount of time, gram-negative can appear gram-positive.

What is the function of mordant?

Unbinding dyes on fabrics is accomplished with the use of a mordant or dye fixative. The mordant or fixative works by establishing a coordination complex with the dye, which then adheres to the cloth (or tissue). It may be used to color materials as well as to increase stains in cell or tissue preparations, among other things.

What does endospore mean?

Endospore — A differentiated cell generated within the cells of some Gram-positive bacteria that is particularly resistant to heat as well as other hazardous circumstances and agents, such as pathogens. Endopsore are the dormant stage of certain bacteria’s life cycle that develops as a result of exposure to harsh environmental circumstances.

What does the endospore do?

It enables the bacteria to develop a dormant and extremely resistant cell that is capable of preserving the genetic material of the cell under harsh conditions. It is possible for endospores to withstand attacks from the environment that would typically kill the bacteria.

Why is it important to determine the location of the endospore within the bacterial cell?

Location. The location of the endosporediffers among bacterial species and how they differ from one another is important for identification. Bacillus cereus is one of the bacteria that have an endospore that is centrally located. The endospore can grow to such an enormous size that the cell becomes distended around the endospore.

What is the purpose of Bacillus structure?

It is this structure on the outside of the cell that serves as a second barrier between the bacteria and the environment, while also maintaining the rod shape and withstanding the pressure created by the bacterium’s turgor (turgor means “pressure”).

Why do bacteria produce spores?

Forming spores to shield themselves against environmental degrading chemicals is one of the most typical coping methods for bacteria. When the surrounding environmental circumstances are favorable for bacterial growth and reproduction, endospores germinate and return to the state of vegetative cells (an active bacterial cell that conducts metabolism).

Which of the following are characteristic of the genus Bacillus?

Bacillus species are rod-shaped, endospore-forming, aerobic or facultatively anaerobic Gram-positive bacteria; in some species, cultures may become Gram-negative with age.

Bacillus species are Gram-positive bacteria that produce endospores. Each of the several species in the genus have a diverse set of physiological properties that enable them to survive in a variety of different environmental environments.

How does an endospore containing cell look after Gram staining quizlet?

What does an endospore look like when it is gram stained? Sporulated cells are purple or pink in color, with circular holes in the center of the cell.

How does an endospore containing cell look after Gram staining?

When using the Gram staining process, it is possible to obtain two distinct colored stains. Finally, when endospore staining is performed, vegetative cells will be stained red due to the presence of the Safranin counterstain. If endospores are present in the sample, the malachite green stain will be retained by the endospores, which will look bluish-green in color.

Why is a Gram stain generally done prior to an endospore stain?

Prior to the use of the endospore staining process, the gram staining procedure was often used to categorize isolated bacteria into the widest possible groupings. Alternative stains, on the other hand, provide for a far better degree of accuracy in the determination.

Why is endospore staining important?

What is the significance of endospore staining?. It aids in the identification of the few medically significant genera that generate endospores, which are rare. It is used to distinguish between bacteria and protozoans under a microscope. It aids in the identification of the few medically significant genera that generate endospores, which are rare.

What does a positive result for the endospore stain indicate about the organism quizlet?

What does a positive result for the endospore stain tell you about the organism it was used to stain? … because an endospore stain is a sort of staining process that is differentiated from others It enables us to view both spores and vegetative cells at the same time. As a result, it is not required to include a separate negative control comprised solely of vegetative cells in the experiment.

What types of bacteria does an endospore stain differentiate between?

The primary goal of endospore staining is to distinguish bacterial spores from other vegetative cells as well as to distinguish spore formers from non-spore formers in a bacterial culture.

What is the function of the Z ring in binary fission quizlet?

What is the role of the Z ring in the process of binary fission? It contracts at the septum, forming a contractile ring.

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What factors regulate the formation of the Z ring at mid cell site during binary fission?

During the vegetative growth of bacilli that divide by binary fission, the Z ring develops near the midway of the cell wall. Neither the Min proteins nor the condition of the chromosome are able to positively influence this medial location.

Why do bacteria have different generation times?

The cells divide at a consistent pace, which is determined by the content of the growth medium and the circumstances of incubation in which they are grown. The generation time of a bacterial culture, as well as the doubling time of the bacterial population, is used to represent the rate of exponential growth of a bacterial culture.

Why a bacterium that should be gram-positive might turn out gram-negative?

When the skin has been over-decolorized, either by extended contact to the decolourizer or through the use of acetone alone. It occurs when the cell wall is destroyed by exposure to lysozyme or antibiotics that act on the cell wall such as Penicillin.

Why do Gram positive bacteria and gram negative bacteria appear different in Gram staining?

It has been found that Gram positive bacteria (which have a thicker peptidoglycan layer in their cell membrane) retain crystal violet stain during the decolorization process, while Gram negative bacteria (which have a thinner peptidoglycan layer) lose the crystal violet stain and turn yellow during the decolorization process.

Why is crystal violet used in Gram staining?

Crystal violet is used as the principal stain in the gram staining procedure.

Because this basic dye is positively charged, it clings to the cell membranes of both gram negative and gram positive cells. … Gram’s Iodine is used as a mordant. This forms a huge complex with the crystal violet, which clings to the cell membrane as a result of the binding.

Why is gram stain called a differential stain?

This type of stain is known as a differential stain because it distinguishes between Gram-positive and Gram-negative bacteria. Bacteria that stain purple when subjected to the Gram staining method are referred to as Gram-positive bacteria, and bacteria that stain pink are referred to as Gram-negative bacteria.

What is the result of Gram staining?

What exactly do the results of a gram stain mean?. Gram-positive bacteria will look purple under a microscope as a result of the staining procedure utilized, whereas gram-negative bacteria would appear pink under a microscope. Additionally, the shape, size, and number of germs present will reveal information regarding your infection.

Why is culture Age important in the Gram reaction quizlet?

For a correct gram response, what is the optimal culture age that should be used? Because older cells do not retain stain as well as younger cells, older cultures of gram positive cells may provide false negative findings (for example, pink cells). The finest cultures are those that last 16-18 hours.


Why is it necessary to use an older culture of Bacillus quizlet for this exercise? Why was it required to use an old bacillus culture for the spore stain? Why was it necessary to use an old bacillus culture for the spore stain? Endospores do not readily stain with a variety of dyes. Maybe you’ve seen them before. Some oral bacteria create extracellular capsules, which are neutrally charged and are produced by other oral bacteria. If this is the case, how is it possible to watch flagella in action?

See more entries in the FAQ category.

Complete Endospore Stain Lab – BIOL 2420 – Medical Microbiology – LSC

Report on the Microbiology Lab Notebook at LONE STAR COLLEGE – MONTGOMERY Endospore Staining – Exercises 3 through 8 3rd of March, 2020 Introduction Several bacterial species are capable of differentiating into dormant cells known as endospores when their environment is unfavorable for development, such as when nutrients are depleted or when temperatures are excessively high. It is possible for endospores to persist in this form for extended periods of time since they are extremely resistant to heat and chemicals.

Purpose The goal of this lab is to visualize and examine endospores before and after they have been stained with counterstain.

The keratin included inside the endospore coating may have an effect on the stain’s ability to be absorbed by the endospore.

Fill the bottle halfway with water.

Free Flashcards about Mico lab quiz 2

Question Answer
What is the most common differential stain Gram stain
Gram stain 1st test run on a specimen brought into a lab
What is a gram stain used for To distinguish between a gram + cell and a gram – cell
Why gram + purple Thick peptidoglycan cell wall, holds tight to crystal violet after iodine sets the stain
Why gram – pink Thin cell wall and LPS outer membrane, cell takes in color of secondary stain- safranin
Theoretically could you use any color for your primary and counter stain as long as their not the same color Yes it would be best if the primary stain was darker; counter stain lighter
Capsules are Mucoid polysaccharide or polypeptide layers- repel most stains
Why are capsules important Increase virulence by resisting phagocytosis
How is a capsule stain different Use a negative staining process, acidic stain, capsule is colorless
Acidic stain Background (Congo red)
Basic stain Cell (manevals stain)
Capsule is colorless White clearing around stain
Why a no heat fixation step durning a capsule stain Causes cells to shrink, leaves and artificial white layer around cell, mix cells with serum or albumin-makes cells adhere to slide
What does a endospore stain do for us Differential stain used to detect endospores
Endospores Dormant form of a bacterium, allows it to survive poor environment, cell will form spores when requirements for life are unavailable ie: nutrients, oxygen, water
What does the endospore staining process help Helps us to identify bacterial species because location and shape of spores is unique
Where can the location of the spores be Center, terminal, subterminal
Shape of the spore Spherical, oval
What does the steam do durning a endospore stain Drives green stain into spores
What happens for the cells to stain pink durning an endospore stain Green washes out of cell durning decolonization(water), and cells take on counter stain
The 5 day culture will have A lot more spores (green)
What bacteria was used for the 2 day and 5 day endospore stain Bacillus subtilis culture
What bacteria was used for the capsule stain Klebsiella pneumoniae
What bacteria was used for the gram + gram stain Staphylococcus epidermidis
What bacteria was used for the gram – gram stain Escherichia coli
Failure to add the iodine in gram stain Crystal violet will wash off of gram +. Both + and – will be pink
Failure to apply the decolorizer in gram stain Decolorizer- removes primary stain in gram -. No decolorizer means the crystal violet retained by gram -. Both + and – will be purple
Failure to apply the safranin in gram stain No counter stain. + will be purple – will be colorless
Reversal of crystal violet and safranin stains in gram stain Safranin washed out of gram – cells. Counter stain is darker than primary stain so both gram + and – will be purple
If you saw eukaryotic cells on your gum line, they were most likely your own epithelial cells. Are you gram + or harm -. What is it about your cell structure that would allow you to predict this result Cells act like gram – cells. Epithelial cells have a plasma membrane andno cell wall
Why does this excerise call for 5 day old culture of Bacillus 5 day old culture is dying off, lacking in nutrients, which triggers sporulation
Spores do not stain easily. Perhaps you have seen them as untainted white objects inside bacillus species in other standing procedures. If they are visible as untainted objects in other stains, of what use is the endospore stain A. Identify spores. B. Rule out spore- like structures including inclusions, vacuoles
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Welcome to Microbugz – Endospore Stain

Endospore Stain is a stain that is used to identify endospores. The endospore stain is a differential stain that is used to see bacterial endospores in their natural environment. Endospores are generated by bacteria belonging to a few species, such as Bacillus. Bacteria can live in adverse environments because they produce spores. Spores are resistant to high temperatures, desiccation, chemicals, and radiofrequency radiation. Following exposure to harsh circumstances, bacteria can produce endospores within 6 to 8 hours of being subjected to the same conditions.

  1. Spores are biologically inert and dehydrated at the time of harvest.
  2. After being exposed to suitable circumstances for 90 minutes, spores can germinate and develop into a vegetative cell.
  3. They can be classified as either central, subterminal, or terminal.
  4. Terminal endospores are found near the tip of the vegetative cell’s apical segment.
  5. Endospores can also have a diameter that is more or less than that of the vegetative cell.
  6. These endospore traits are similar among spore-forming species, and they may be used to identify the organism from which they are originating.
  7. Heating causes malachite green, the principal dye used in the technique for staining endospores, to be absorbed into the cells.

Moreover, because malachite green is a water-soluble dye that does not stick well to cells, and because heat has ruptured the vegetative cells, the malachite green rinses easily off the vegetative cells, allowing them to rapidly absorb the counterstain. The staining process may be found here.

2.4 Staining Microscopic Specimens – Microbiology

Due to the widespread use of antibiotics in medical and agricultural settings, bacteria have evolved to become increasingly resistant to these medications. bacterial strains that are resistant to antibiotics, such as methicillin-resistant S. MRSA (methicillin-resistant Staphylococcus aureus), which has developed a high level of resistance to many antibiotics, is becoming an increasingly concerning problem, to the point where research is underway to develop new and more diversified antibiotics.

Researchers utilized the fluorescent dyeSYTOX Green to stain samples of MRSA during a test with a novel antibiotic generated from a marine bacteria, MC21-A (bromophene), in order to determine its efficacy.

Live cells will not absorb the dye, but cells killed by an antibiotic will, since the drug has destroyed the bacterial cell membrane, absorb the dye.

Antibiotic prescriptions are becoming increasingly discretionary among health care practitioners as a result of this trend, which is becoming more widespread.

A sick patient may reasonably object to this cautious approach to prescribing antibiotics, which is based on the assumption that the patient is sick.

However, this is not always the case.

Lab Exam 1 Flashcards by B Wade

  1. Undulate (wavy)
  2. Entire (smooth, with little abnormalities)
  3. Rhizoid (branching like roots)
  4. Lobate (lobed)
  5. Filamentous
  6. Rhizomatous
  1. It might be flat, elevated, convex, pulvinate (extremely convex), umbonate (raised in the middle), or any combination of these.

With regards to bacterial growth, what does the term pure colony or colony-forming unit mean?

  • Transfers over books, study materials, and other resources are not permitted. Maintain orderly storage of your goods and make certain that they are not arranged in a way that might lead to contamination. When not in use, store all media tubes in the test tube rack, regardless of whether they are sterile or not. Please take your time. Do not ever pick up a tube culture by the cap. Try not to inhale across other cultures. Reduce the amount of time spent interacting with peers in order to minimize infection.

In which hand should the tube cap be held while transferring cultures from one medium to another?

  1. To begin, use a heat-fixed emulsion. Fill in the smear with a strip of bibulous paper, add a few drops of malachite green stain, and steam for five minutes. Using water, rinse the slide. Counterstain for 1 minute with safranin
  2. Remove counterstain. Gently dab the surface dry

When heated, malachite green is driven into the endospore, where it breaks down the keratin that protects it. ** Because malachite green is water-soluble and has a low affinity for cellular material, it may be used to decolorize vegetative cells and spore mother cells, which can then be counterstained with safranin after they have been decolorized with water. The purpose of the safranin counterstain is to stain bacterial cells in order to create contrast between them and the endospores when seen under a microscope.

What stain can stain vegetative cells?

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