Full Answer
What is an agar slant tube?
An agar slant tube (or simply an agar slant) is a screw-capped culture tube partly filled with an agar mix such as nutrient agar, R2A agar, or TSA (figure 1). To make it a slant tube the agar is allowed to cool with the tube laying at an angle, resulting in a large surface area for spreading a culture. What is the purpose of agar slants?
What is the purpose of capping the agar tube?
This creates a slanted surface on which to inoculate bacteria. Creating a large plug of agar medium and capping the tube prevents desiccation and allows for the long-term storage of living bacterial cultures. It is essential that the tubes and medium are sterile before use.
What is a gelatinous agar?
Agar (noun): a gelatininous material derived from algae, specifically used as a culture medium of bacteria and other cells for diagnostic or laboratory experiments purposes. The agar that we find in science laboratories has been dissolved first in boiling water and then cooled. That is why it looks gelatinous.
What is the composition of agar?
Agar is a polymer that is composed of subunits of galactose sugar. According to the Biology-Online Dictionary: Agar (noun): a gelatininous material derived from algae, specifically used as a culture medium of bacteria and other cells for diagnostic or laboratory experiments purposes.
What is agar slope method?
Agar slants are created by bringing agar to the boiling point and pouring it into a test tube. Before the agar cools and solidifies, the test tube is set on its side. Once the agar is cooled, the test tube can be stored upright, and the agar inside has a slanted appearance.
What is the purpose of agar slants?
Agar slants are commonly used to generate stocks of bacteria. Agar plates can be used to separate mixtures of bacteria and to observe colony characteristics of different species of bacteria (you will perform an experiment in this lab to illustrate this).
What is nutrient agar slope?
Nutrient agar is a great general purpose growth medium suitable for most bacteria and fungi. These ready prepared sterile agar slopes or slants are a valuable time saver. Available in a pack of 10, 25 or a great value box of 144. 10ml. Ready prepared nutrient agar petri dishes are also available.
Why are agar slant in slant position?
Slanting gives the bacteria a greater surface area on which to grow in a tube. Agar slants are also useful in maintaining bacterial cultures, more so than stacks of Petri dishes. Multiple cultures are easily placed into test tube racks and stored under refrigeration.
Why are agar slants better than agar plates?
Why are agar slants better suited than agar plates to maintain stock cultures? Slants are better suited because they can be capped, preventing the agar and culture from drying out. The cap also prevents airborne contaminates from entering the slant. Slants take up less storage space.
What is the difference between agar slant and agar deep?
If the medium in the test tube is allowed to harden in a slanted position, the tube is designated an agar slant; if the tube is allowed to harden in an upright position, the tube is designated an agar deep tube; and if the agar is poured into a Petri dish, the plate is designated an agar plate.
What is agar slant in microbiology?
An agar slant tube (or simply an agar slant) is a screw-capped culture tube partly filled with an agar mix such as nutrient agar, R2A agar, or TSA (figure 1). To make it a slant tube the agar is allowed to cool with the tube laying at an angle, resulting in a large surface area for spreading a culture.
How long do agar slants last?
An agar slant allows you to store your favorite mushroom in a suspended state for up to 12 months!
How do you make nutrient agar slants?
Nutrient Agar Slants: Prepare a nutrient agar medium and boil it with stirring until all the agar is melted. You must stir this very well so that the melted agar is distributed throughout the medium. 3. Use a pipette to transfer about 5 ml of molten agar to each test tube.
What do you mean by slant?
to veer or angle away from a given level or line, especially from a horizontal; slope. to have or be influenced by a subjective point of view, bias, personal feeling or inclination, etc. (usually followed by toward). verb (used with object) to cause to slope.
What is a slant culture?
[ slănt ] n. A culture made on the slanting surface of a solidified medium in a test tube that has been tilted to provide a greater area for growth. slope culture.
How do you know if a slant is contaminated in agar?
Checking for Contamination Look for signs of fungal contamination. Fungal contamination will appear as fuzzy, filamentous, or hair-like growths, and should be visible to the unaided eye. Fungal contamination often occurs right along the edge of an agar plate.
What is agar slant in microbiology?
An agar slant tube (or simply an agar slant) is a screw-capped culture tube partly filled with an agar mix such as nutrient agar, R2A agar, or TSA (figure 1). To make it a slant tube the agar is allowed to cool with the tube laying at an angle, resulting in a large surface area for spreading a culture.
What is the purpose of using agar plate agar slant and broth in culture for microorganisms?
Agar plates will be used for isolation and some assays, and for short term maintenance of cultures. Agar slant tubes will be used for long term maintenance of isolates. Broths (liquid media) will be used to grow isolates for some assays or for the assays themselves.
What is slant culture in microbiology?
[ slănt ] n. A culture made on the slanting surface of a solidified medium in a test tube that has been tilted to provide a greater area for growth.
When agar slants are used to observe cultivation characteristics Why is it preferable to use in inoculating needle rather than an inoculating loop?
This preview shows page 2 - 3 out of 3 pages. E. Why is it important to use a needle rather than an inoculating loop wheninoculating a motility tube? It is important to use a needle rather than an inoculating loop because the needleis used to transfer the specimen to the soft agar medium.
How to make agar foam?
Add a stir bar, place the beaker in a microwave, and heat until the agar begins to foam. Watch carefully so that the agar does not boil over.
Why are agar slants used?
Agar slants are used for storing pure cultures for a moderately long term. There is minimal risk of contamination or of losing the culture due to the medium drying out because the small volume of air inside the tube and narrow opening combine to limit water loss and exposure to outside air, including dust and other particles.
How to remove a slant tube?
With the end of the loop or stick touching the agar surface near the bottom, move it back and forth slightly as you gradually pull it up toward the top of the slant. Remove it, again pass the mouth of the tube through a flame (optional), and replace the cap.
How to transfer culture from a single colony to an agar?
To transfer material to a slant we hold the tube at an angle, loosen the cap so that it can be pulled straight off, and pick up some culture from a single colony. With the colony material on the loop, remove the cap using the little finger of the hand holding the loop, pass the mouth of the tube quickly through the flame (optional), then insert the loop or stick into the tube.
How to make slants in agar?
We prepare slants by preparing agar in a beaker, distributing it into tubes, sterilizing the capped tubes, and laying them at an angle to make a slanted surface as they cool .
Can you use a loop to inoculate agar?
Different investigators and technicians will conduct the inoculation differently, as can be seen in videos on the web. Some do not flame the mouth of the tube, others use different ways of transferring material to the agar surface. In our lab you will have the option of using a loop to conduct the transfer (flame required) or using a sterile inoculating stick (no flame required).
Who created BIOC 318?
Created by David R. Caprette, Teaching Professor, Rice University ([email protected]) 17 Feb 2017 for the course BIOC 318, Laboratory Studies in Microbiology. Please feel free to copy and/or modify these materials for use in your own academic or other nonprofit program. If you don't mind letting me know of such intentions I'll be happy to hear from you.
What is a slant tube?
A slant tube is a test tube prepared by pouring in a melted agar medium while the tube is tilted. This creates a slanted surface on which to inoculate bacteria. Creating a large plug of agar medium and capping the tube prevents desiccation and allows for the long-term storage of living bacterial cultures. It is essential that the tubes and medium ...
Why do we inoculate agar tubes?
The purpose of inoculating an agar slant tube is for the long-term maintenance of an isolated culture of microorganisms. Agar is a complex carbohydrate from algae that is infused with water and nutrients so that bacteria and other organisms can grow on its surface.
What temperature is used to solidify agar?
Solid media usually use agar, which is solid below 113 degrees Fahrenheit, to solidify them. It accomplishes this with a concentration of between 1 percent and 2 percent. ADVERTISEMENT.
What are the different substances that bacteria need to live?
Bacteria require several different substances to live including water, a source of energy, carbon, sulfur, nitrogen, phosphorus, vitamins and minerals.
What Is Agar-Agar?
This jellylike substance is a mix of carbohydrates that have been extracted from red algae, a type of seaweed. Agar has several uses in addition to cooking, including as a filler in sizing paper and fabric, a clarifying agent in brewing, and certain scientific purposes. It is also known as China glass, China grass, China isinglass, Japanese kanten, Japanese gelatin, and dai choy goh, and is used in certain Japanese dessert recipes.
What is pectin powder used for?
Pectin powder, derived from citrus fruit and berries, is often used to thicken jams and jellies and can be used in place of agar. It does include sugar, so it is best in sweet recipes. A manufactured product available from a variety of brands is an unflavored vegan gel, a vegetarian gelling powder that is a combination of a variety of ingredients including carrageenan.
How long does it take for agar to dissolve?
Dissolve the agar in a liquid in a small saucepan over medium-high heat, bring to a boil, and then simmer until slightly thickened, about five to seven minutes. Agar powder dissolves more quickly than flakes and strands, which need extra soaking time and stirring to fully dissolve. (Flakes, bars, and strands can be processed into powder before using.)
What is the difference between agar and gelatin?
Whereas animal-based gelatins are made from livestock collagen (from the cartilage, bones, skin, and tendons), agar-agar is purely vegetarian, coming from the red algae plant. The two setting agents also behave differently and need to be prepared in distinct ways when incorporating into a recipe. Agar-agar needs to boil in order to set, while gelatin can simply dissolve in warm water; that is because agar melts at 185 F, whereas gelatin melts at 95 F. Agar also sets more quickly than gelatin and doesn't need any refrigeration.
Why is agar used in medicine?
In Eastern traditional medicine, agar has been used to treat conditions like diabetes and constipation. Agar is also beneficial in preventing bone loss due to the high concentrations of calcium and manganese. 1 .
Can you use agar powder in a food processor?
The powder is also used in a 1:1 ratio when substituting for gelatin—when using flakes, 1/3 the amount of gelatin called for should be added. The agar bars, sticks, and flakes can be processed into powder form in a blender or food processor. Similar to gelatin, flavored and colored versions of agar are available.
How long does agar-agar last?
All forms of agar-agar should be stored in an airtight container in a cool, dry spot such as the pantry, where it will last at least eight months.
What happens if you simplify the point slope equation above?
If you simplify the point slope equation above you get the equation of the line in slope intercept form.
How to find slope of a line?
Find slope by finding the difference in the y points, and divide that by the difference in the x points.
What is the inverse of 4/1?
Second, take the inverse of that number. 4 is a whole number so its denominator is 1. The inverse of 4/1 is 1/4.
What is the slope of a line?
The slope of a line is a measure of how steep it is.
What does perpendicular mean?
Perpendicular means the lines form a 90° angle when they intersect.
What is the y intercept of a line?
The y-intercept of a line is the value of y when x=0. It is the point where the line crosses the y axis.
Do lines intersect when you know the slope of a line?
If you know the slope of a line, any line parallel to it will have the same slope and these lines will never intersect.
