What are the advantages and disadvantages of using a hanging drop mount?
What are the advantages and disadvantages of using a hanging drop mount?
Advantages: Like the wet mount, the hanging drop method preserves cell shape and arrangement. The Vaseline-sealed depression also slows down the drying-out process, so the organisms can be observed for longer periods. Disadvantages: The hanging drop method is also far too risky to use with highly pathogenic organisms.
What is the advantage of the hanging drop method over the wet mount method in the demonstration of motility?
The wet mount tend to dry out quickly under the heat of the microscope light; it is simpler to perform than the wet mount, but it is useful for short-term observation only. The hanging drop is a more complex technique, but it allows for longer-term obervation and more reliable observation of motility.
What are stab tubes used for?
The stab tube will allow your inoculation loop reach deep down into the media where free oxygen is at a minimum. Inoculating liquid media in a test tube and leaving it to stand (no shaking!) can also allow you to grow colonies under low-oxygen conditions in liquid media.
What does negative motility test mean?
Negative: Growth that is confined to the stab-line, with sharply defined margins and leaving the surrounding medium clearly transparent.
What is hanging drop technique?
The hanging drop technique is a well-established method for examining living, unstained, very small organisms. The traditional procedure employs a glass slide with a circular concavity in the centre into which a drop of fluid, containing the ‘microorganisms’, hangs from a coverslip.
How do you stab culture?
Unlike an LB Agar plate, a stab culture is created by piercing the LB agar with the bacteria instead of spreading it on the surface. The bacteria in a stab culture grow up and out of the puncture point to spread across the surface of the stab culture.
What is wet mount technique?
Wet Mount. In a wet mount, a drop of water is used to suspend the specimen between the slide and cover slip. This method will help prevent air bubbles from being trapped under the cover slip. Your objective is to have sufficient water to fill the space between cover slip and slide.
How do you do a wet mount?
A sample of the vaginal discharge is placed on a glass slide and mixed with a salt solution. The slide is looked at under a microscope for bacteria, yeast cells, trichomoniasis (trichomonads), white blood cells that show an infection, or clue cells that show bacterial vaginosis.
Which bacteria has darting motility?
Darting motility is a rapid motion observed in some gram-negative bacteria, also called Shooting Star motility. This motion is so quick that often no change is observed in the position of the bacterium. The two most common examples of microbes showing this kind of motility are Vibrio cholerae and Campylobacter jejuni.
How do you observe bacterial motility?
There are a variety of ways to determine the motility of a bacterium—biochemical tests as well as microscopic analysis. If a fresh culture of bacteria is available, microscopy is the most accurate way to determine bacterial motility, and ‘hanging drop method’ is a commonly used microscopic technique.
Why do we use stab culture?
Stab cultures are similar to agar plates, but are formed by solid agar in a test tube. Bacteria is introduced via an inoculation needle or a pipette tip being stabbed into the center of the agar. Stab cultures are most commonly used for short-term storage or shipment of cultures.
Which loop is used for stab culture?
Straight Nichrome Wire for Stab Culture is supplied by Micromaster. It contains a Nichrome loop without any holder. An inoculation loop, also called a smear loop, inoculation wand or microstreaker, is a simple tool used mainly by microbiologists to retrieve an inoculum from a culture of microorganisms.