BSCI223-Assesment 1, Part 4

Escherichia coli Mycobacterium phlei Bacillus Micrococcus subtilis luteus A B Figure 1: Agar Slant Cultures of Bacteria (Gary E. Kaiser, Ph.D.- Professor of Microbiology) . Observe and describe the colour of the slant cultures (A-D) in fig 1. ( . Define the following terms: pure culture, sterile medium, inoculum, aseptic technique, and colony. What is the name of the cultures that you used . Where they gram negative or positive Define the following terms: psychrophile, mesophile, thermophile, and hyperthermophile.

Please help me with these two

Could you please assist with correct number?

A culture of S. cerevisea has an overnight OD of 2.3 (1.0 OD is approx 1.0x107 cells/ml) You will be plating 100µl onto agar and want the final count of colonies on the plate to be around 300 colonies.  How much of the 2.3 OD culture must you use to get a 500µl subdilution (with sterile water), so that you have diluted enough to get approx 300 colonies per 100ul

The colony forming units (CFU)/ml in sauerkraut brine are given for different types of bacteria except for leuconostoc (shaded column). To obtain the Leuconostoc counts for different days, 40 microlitre of sauerkraut brine was 10-fold diluted and the CFU was determined by plating different dilutions on agar plates. For Day 0 56 CFU were counted in 10-1 dilution, Day 1 81 CFU were counted in 10-3 dilution, Day 2 86 CFU were counted in 10-3 dilution Day 5 78 CFU were counted in 10-5 dilution     Calculate the CFU/ml of leuconostoc in the brine for the 4 different days. Show your calculation

Hello,  Can you please help me with the next question abnout bacterium? (I would apreciate a short answer). Let's say that the growth you are observing is occurring under the following factors: Oxygen-rich environment; temperature range is 25-40 degrees Celsius; and uses inorganic chemical compounds as the source of energy. What terms would you use to describe the bacteria? Thank tou un advance!

Using one of the graphs obtained with the medium II, name the different phases of the bacterial growth and indicate the starting and ending time points of these phases as well as the physiological characteristics of the bacteria during each phase

A bacterial strain has a generation time of 30 min, how long would it take an exponentially growing culture to increase from a titre of 5 x 103 cells per ml to 4 x 109 cells per ml? How many generations would have elapsed? Show all of your calculations. G = t/n to calculate generation time (i.e. for population to double)    During the growth of the culture, periodic observations of the cells under the microscope have revealed the occurrence of typical rod-shaped cells. However, after further incubation, they appeared to change their morphology to form small oval or spherical-shaped structures. What do these structures likely represent? And what are the likely factors contributing to this observation? Explain what growth phase this culture will be in.

One of the early results shows that the post-centrifugation pellet of encapsulated cells also contains EA1 and/or Sap. Why is this not proof that Bacillus anthracis cells have both an S-layer and a capsule simultaneously? I need help finding the answer in the article and explain in short answer  link to article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC106848/

One of the early results shows that the post-centrifugation pellet of encapsulated cells also contains EA1 and/or Sap. Why is this not proof that Bacillus anthracis cells have both an S-layer and a capsule simultaneously? I need help finding the answer in the article and explain in short answer  link to article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC106848/

Solve the following parts.    a. What phase of the bacterial growth curve does a chemostat maintain? b. Define the term generation time? c. What is a culture medium?

just answer question ---  dont need explanation

Question:- How to perform a bactericidal test bactericidal test of Dental Pulp Stem Cell (DPSC)?

Below is shown a growth curve for an E. coli culture. As indicated, the culture was incubated in the absence of a carbon source for 2 hours until Glucose and Lactose were added; Glucose was used up after 5 hours, and Lactose was used up after 8 hours. During the time-course, you take four samples, labeled A-D, after 1, 3, 7 and 9 hours, respectively, as indicated under the graph. Assuming there is cAMP present at t=0, for each sample identify whether CAP and/or the Lac Repressor would be bound to the DNA, and explain why.

Plaque assay (Bacteriophage Titer) Answer questions 2 & 3 2. Why don't bacteriophages continue spreading over the entire plate until all of the E. coli cells on the plate are lysed?  3. Why is it important that bacterial cells should be in the exponential growth phase for this experiment?

1- Why was the T4 and E.coli mixed together in top agar and then poured on the plate instead of just spreading the two together with a glass spreader on the plate? 2- When doing the titration and isolation of the T4 phage, E.coli diluted for you to 10e7 cells/ml. why was a diluted culture used? 3- After doing the titration of T4 phage, you find your dilution plates are all TNTC. how could this have happened? 4- Could you isolate phages that infect E.coli from raw sewerage? explain.

The world is facing a Corona Virus (COVID-19) Pandemic and as a potential scientist and a microbiology student, you have been required to prepare the easiest and most affordable hand sanitizer that can be utilized by students in various microbiology laboratories. Each student in your class has been given 96% ethanol and you are required to prepare 70% ethanol hand sanitizer in a 2L spray bottle. Describe clearly the method you will use in order to achieve the aim of the practical.