A pure culture of an unknown bacterium was streaked onto plates of a variety of media. You notice that the colony morphology is strikingly different on plates of minimal media with glucose compared to that seen on trypticase soy agar plates. How can you explain these differences in colony morphology?

A pure culture of an unknown bacterium was streaked onto plates of a variety of media. You notice that the colony morphology is strikingly different on plates of minimal media with glucose compared to that seen on trypticase soy agar plates. How can you explain these differences in colony morphology?

Basic Clinical Laboratory Techniques 6E

6th Edition

ISBN:9781133893943

Author:ESTRIDGE

Publisher:ESTRIDGE

Chapter7: Basic Clinical Microbiology

Section7.4: The Gram Stain

Problem 2RQ

See similar textbooks

Similar questions

Is the telluride glycine agar? (TGA) a complex or defined medium? Explain based on its composition. What kind of Media is TGA explaining based on what kind of microorganisms it allows to grow?
Your instructor asks you to isolate and identify the organisms in an unknown culture. You find that the culture contains two gramnegative bacilli that produce swarming colonies. What biochemical test would you use to identify the bacilli? Justify your answer.
Using your fingers, you are asked to aseptically touch the surface of a sterile agar plate. Illustrate the possible result from this step if your fingers are (a) unwashed – touched various things prior to placing on agar surface, and (b) washed with soap or disinfected with 70% alcohol. Describe the relative abundance of microbial growth observed on the plates. List and draw the possible characteristics of an isolated bacterial colony that can be observed based on type of (a) margin, (b) elevation, (c) texture, and (d) optical property.
During media preparation, you observed that the agar medium did not solidify after sterilization even after incubating it for 1 hour at room temperature. What could be the reason behind this?
Why does motility media contain a lower amount of agar than ordinary agar?
E.coli was incubated with aeration in a nutrient medium containing two carbon sources provided one at a time, and the following growth curve was made from this culture. a. Explain what happened at the time marked x. b. Which substrate provided “better” growth conditions for the bacteria? How can you tell?
Why do cells need to be kept in the freezing devices first then transferred to liquid nitrogen storage in crypto preservation? In addition, why are antibiotics not used in the cell freezing media? Why FBS concentration higher than 10% (10% is the standard concentration in complete growth media) is recommended in cell freezing media?
MacConkey agar is often used to differentiate E. coli from other Gram-negative rods. The recipe for MacConkey agar is given in the table. Suppose you plated a mixed culture of Escherichia coli, Bacillus subtilis, and Streptococcus pyogenes onto a MacConkey agar plate. Which species would grow, and how would they appear? Why would the others NOT grow?
If you altered the conditions under which bacterial growth normally occurs (i.e. increase the temperature of incubating a culture from 35 to 40°C), what effect would this have on the bacterial growth curve of the organism under study?
The acid fast bacterium, Mycobacterium smegmatis, is relatively safe for students to work with because of its thin cell wall. If a gram stain is to be performed on this particular microbe, it often takes the gram stain reaction. Why?
You are doing water analysis. After 24 hours, your pour-plate reveals the presence of Proteus-looking colonies. What is the explanation why you need to eliminate these plates from your experimental data?
Why is the colony diameter of the yeast culture grown on potato dextrose agar is larger than those grown on acetate agar? Give and discuss the reasons for this different in growth.