MacConkey agar Essays

“Post-Lab Questions” What ingredient(s) makes MacConkey agar selective for Gram-negative bacteria? The ingredients that make MacConkey’s Agar selective is a pH indicator (neutral red), and a disaccharide ( Lactose) “2. What types of bacteria are inhibited on MacConkey agar?” Gram-Positive bacteria that are inhibited with MacConkey agar due to crystal violet and bile salt presence . “3. What ingredient(s) makes MacConkey agar differential?” MacConkey agar are inhibited by a pH indicator (neutral red)

E. Discussion: In order to synthesize the polymer, Nylon 6,10, we had to complete a few steps to create the chemical reaction that combined sebacoyl chloride and hexamethylenediamine. First we measured the mass of the two graduated cylinders when they were empty, and measured it again after they were filled with sebacoyl chloride and hexamethylenediamine. We did this in order to find the measurements of the reactants. When we measured the graduated cylinder when they were emptied, one weighed at

the streak plate technique to isolate separate colonies. We used a nutrient and MacConkey agar plate to begin. We used both agars because the nutrient agar allows us to grow the largest number of different types of microbes, yet not all bacteria can grow because it is rich with beef broth and some yeast extracts. McConkey agar only allows gram negative bacteria to grow while inhibiting gram positive bacteria. This agar also contains a pH indicator which allows us to detect if fermentation occurred

phenospecies test (morphology and biochemistry), based on the protocol of SNI 7303 (2009), plus one control isolate the A. hydrophila ATCC 7699 obtained from Microbiologic Co. Figure 1. The Isolate of A. hydrophila ATCC 7699 Grown on the Rimler-Shoots Agar Medium + Antibiotic Novobiocin at 37C for 24 Hours 3.2 The

Bacillus thuringiensis was isolated from raw milk (Taif, KSA) on nutrient agar at 37oC for overnight. The supernatant of the bacterial isolate was screened for synthesis of AgNPs. The bacterial isolate was morphologically and biochemically characterized according to Bergy’s Manual of Systemic Bacteriology[21]. Also, this bacterial isolate was further identified by 16S rRNA sequencing. The culture was maintained on a nutrient agar plate/slants at 4°C and as glycerol stocks 40% at −70°C. Preparation of

selecting specific bacteria, I looked for the best combination of variation and choosing across all five of my plates for both agars. Through using morphological observation I was able to determine different bacteria such as colonies that are irregular and circular continuing with variations of elevations and edges. Also, the use of solid cultures such as the use of agar is rewarding because the bacteria will not move creating the ability to have many colonies on the plate while still being isolated

phosphate to ammonia and ammonium hydroxide, which then use to alkalinize the agar. At pH 7.5 or higher, the agar will turn blue. EMB coliform Eosin Methylene Blue Agar is a selective medium because it contains dyes eosin Y and methylene blue, which can inhibit the growth of Gram-positive organisms. Since the unknown bacteria is gram negative, the test is successful as the unknown bacteria grown colonies on the EMB Agar. EMB test is also a differential test because it contains lactose, which encourages

petri dishes were obtained air and skin. The air petri dish lid was left open so airborne bacteria could land in the petri dish. The skin petri dish was divided into four sections for each lab member. We each pressed our fingerprints into the correct agar section to capture bacteria from our skin (Holbrook and Leicht, 2017).

Chemistry Exploration Topic: determining the activation energy of a chemical reaction Research Question: What effect does temperature of the chemical reaction have on the activation energy ? ICT: Microsoft Word Autograph Microsoft Excel Introduction This experiment is designed to help in estimating the activation energy of the rate-limiting step in the acid catalyzed reaction of acetone with iodine. This is achieved by measuring the reaction rates at different reaction temperatures over

different concentrations) This experiment was performed by two groups using antibiotics Amoxicillin and Vancomycin by each group. Vancomycin data were collected by our group. After the incubation period of the diluted tubes containing antibiotic Vancomycin against S. epidermidis, the results were obtained as below, Tubes: 1 2 3 4 5 6 7 8 9 10 (Image 1 indicates the visual growth of S. epidermidis

.4 Agar Disk Diffusion The antimicrobial tests were carried out according to disc diffusion tests (Lennette et al., 1985, Kim et al., 1995). Cells were streaked on MHA agar plate to obtain colonies at 37°C for 16 hrs after which they were resuspended in sterile saline solution to give an O.D of 0.1 at 600nm. On solidified 2% MHA plate, the bacterial culture is swabbed and sterile disc impression was made, 10 µl plant extracts was loaded on the agar plate. After 10 minutes the plate is incubated

10x, 20x, 30x, 50x,75x and 100x MIC to each well in 12-well plate. Colony counts (CFU/ml) were determined at different time points (T0, T3, T24) by using appropriate dilutions of each culture. Using spot-plating method (32) 10µl was spotted on LB agar plates. However after 24 hour exposure the bacterial cell from dilutions of ≤ 1x102 were washed twice with sterile PBS prior to plating in triplicate. These were then incubated overnight at 37°C. The experiment for each different density was repeated

Materials and Methods The animal experimental procedure was approved by Ethical committee of ICAR-National Institute of Animal Nutrition and Physiology, Bangalore, India. Incubation and in ovo treatment A total of 200 uniform sized eggs (Cobb broiler) were procured from commercial hatchery and incubated with the dry bulb temperature ranging from 99 - 100°F and wet bulb temperature of 85-87°F from day 1 to 18. On day 18, all infertile eggs were removed and the fertile eggs were divided into 3

We took 2 Petri plates containing L-agar and spread 50µl from dilutions 〖10〗^(-3) and 〖10〗^(-5) respectively on L-agar plates by using spreader and incubated them at 37°C for 24 hours. After 24 hours incubation, we selected isolated colony and streak it on L-agar containingPetri plates to purify it. After 24 hours incubation, we got our purified colony, now we checked either it is nitrogen fixing

Bacterium growth on various agar plates Introduction The purpose of this experiment is to show different agar plates inhibit or enable growth of different organisms. Some varieties of media enable the grow of a wide range of organisms such as nutrient agar. Other media are selective which means they contain specific nutrients to encourage the growth of certain organisms. This means other organisms will die due to the selective nutrients such as high concentration of salt which will cause plasmolysis

test that should be performed because it helps narrow down the possibilities by telling one whether the bacteria is gram positive or gram negative. After this test is performed, one shall place bacteria on/in Mannitol Salt agar, MacConkey agar, Eosin Methylene Blue agar, Urea agar, Simmon’s Citrate, Purple Beef broth with Lactose and finally Purple Beef broth with Sucrose. A streak plate should also be made up, this helps one identify the morphology of the colonies. Once the streak plate has been inoculated

the sample was streaked for isolation onto TSA, blood agar, and MacConkey plates. Each plate serves as a first step to identify the unknowns. The TSA (tryptic soy agar) can be used to do a gram stain, which differentiates gram-negatives from gram-positives, based on the structural make up of the cell wall (Carson, 2015). The blood agar plate is used to test for hemolytic activity, which is useful for distinguishing gram-positives. A MacConkey plate is selective by inhibiting the growth of gram-positives

catalase positive which means that it produced enzyme catalase and bubbled when hydrogen peroxide was added to it. Three test were conducted based on the result of the gram staining procedure. Blood agar with a Novobiocin disk was chosen as well as DNase (DNA) and Mannitol Salts (MSA) agar. The Blood agar is a bright red, opaque plate and the streaking or the inoculation technique was a modified streaking for isolation with a heavy quadrant one. This is where the antibacterial disc bacitracin was used

assigned. The unknown that corresponds to this lab report is unknown #19. The unknown was cultured during the first lab experiment using TSA, blood agar, MacConkey as the media. The plates were cultured using the streak plate technique. To begin, the materials were gathered, those materials were the plates that were going to be streaked were (MAC,TSA,blood agar), the loop that is going to be used during the streaking procedure, the mixed culture that contain the unknown. This experiment was conducted

growth inhibitors and, antibiotics are also found on this type of medium (3). The differential and selective media mentioned in this lab are as follows: Mannitol Salt Agar (MSA) plate, MacConkey agar (MC) plate, Eosin Methylene Blue agar (EMB), and Hektoen Enteric Agar (HEA) (3). The MacConkey agar plate and the Mannitol Salt agar plate are both used in the identification of the unknown. The MC plate is a selective and differential medium. It is considered a selective medium because the bile salts