Get Full Essay Get access to this section to get all help you need with your essay and educational issues. What is the difference between a bactericidal and bacteriostatic agent? Between sterilization and disinfecting?
Seriously, borrow a book, read it. This introduction is taken from that section of the textbook and is presented as an attempt to define the term: Aseptic technique is a set of routine measures that are taken to prevent cultures, sterile media stocks, and other solutions from contamination by unwanted microorganisms i.
Since the goal of a biologist is to grow microorganisms or eukaryotic cells without introduction of extraneous organisms, aseptic techniques are crucial for accurate and meaningful experimentation. One should keep in mind that a completely sterile working environment does not exist.
However, there are a number of simple, common sense procedures that will reduce the risk of culture contaminations. Examples of aseptic technique are cleaning and disinfecting laboratory surfaces prior to use, limiting the duration that cultures or media are uncapped and exposed to the air, keeping petri dishes closed whenever possible, effectively sterilizing inoculating loops and other equipment that comes into contact with cultures or media, and avoiding breathing on cultures or sterile instruments.
These precautions will become second nature after practical laboratory experience. What is an Inoculating Loop? The inoculating loop is used for the transfer of liquid or solid bacterial cultures. It consists, simply, of a handle with a thin protruding wire that is molded into a circle at the end.
Many varieties of loops, made of nickel-chromium or platinum wire, are available from many suppliers.
The wire may be permanently attached to a handle or replaceable, and may be obtained as either a straight wire or a twisted loop. Both looped and straight wires are suitable for transferring bacteria from solid media. The inoculating loop must be sterilized immediately before and immediately after use.
The loop can be cooled quickly by gently touching it to an unused part of an agar plate or in liquid medium. Do not blow on a hot loop or wave it in the air to cool it off.
How are toothpicks used? Toothpicks should be placed into a ml beaker with the narrowest end at the bottom of the beaker, covered with aluminum foil, and autoclaved.
The sterile container should be turned on its side during removal of individual toothpicks, to prevent contaminants from falling into the open beaker.
What is a Culture Spreader besides a predictably questionable band name? A spreader is used to evenly distribute bacterial cells from a liquid suspension over the surface of a plate.
A spreader can be easily made by heating and bending a piece of a 4- to 5-mm diameter glass rod, as illustrated in Figure 4. In a pinch, a much less durable spreader can be quickly made from a Pasteur pipet. A pair of needle-nose pliers or similar tool is useful for forming bends in glass. Sterilize after use by immersing in the ethanol.
Adapted notes from course textbook on starting an overnight culture small scale: Prepare 10 mL of YPD from lab stock in a sterile test tube. Follow the instructions for proper sterilization of the inoculating loop. With a cooled loop or sterile toothpick, scoop a small portion of a single isolated colony solid stock.
Alternatively, touch the material on the loop to the glass just above the liquid. The inoculum will enter the liquid once it is put on a shaker. It is not necessary to see the yeast in the liquid medium, because even a few cells will grow to a high density after incubation.
Cover culture with cap or loose foil. Note that there are two racks which tightly hold the test tubes in place in the shaking incubator.
Plate Creation Plates can be made by one of the following techniques. Adapted notes from course textbook on using a Culture Spreader: Cool the spreader by touching it lightly to the agar surface, then spread the culture uniformly around the plate.
Return spreader to ethanol. Allow liquid to dry such that there are no drops visible on the surface.GENERAL MICROBIOLOGY (BIO) SYLLABUS NEW YORK CITY COLLEGE OF The Gram stain.
Bacterial anatomy – discussion only. 59 77 5. The Acid-fast stain (Ziehl-Neelsen).
• Effectively perform the appropriate aseptic techniques required in the handling of bacterial cultures. Anatomy of Bacteria Bacteria are single-cells organisms that have existed on our planet for hundreds of millions of years.
Bacteria are prokaryotic, which means that they lack a nucleus and membrane-bound organelles and they contain a small circular plasmid (DNA) as its genetic material. Aseptic technique is a way to manipulate cultures to minimize the chance of contamination. The most common technique to isolate a pure culture is the streak plate method.
individual bacterial cells will adhere to isolated sections of the plate and form bacterial colonies. A colony is a small area of growth that ideally represents the.
General Microbiology Laboratory Manual BIOL By Paul W. Lepp Second Edition Biol General Microbiology – Spring Streak plate technique is typically used to introduce a pure bacterial sample to a new plate and spread that sample out sparsely enough to facilitate the growth of distinct bacterial colonies.
Microincinerator used to sterilize inoculation loops. Aseptic Technique and Bacterial Anatomy and Morphology Lab, Week ASEPTIC TECHNIQUE AND BACTERIAL ANATOMY AND MORPHOLOGY Introduction Part I: Aseptic Technique The purpose of this experiment is to become familiar with the specific microbiological technique known as the aseptic technique, which is used to avoid contaminating cultures.