TCBS agar was prepared for about 100ml and poured into petri plates, after solidifying, pure colonies of bioluminescent bacteria was streaked. The petri plates were observed after 24 hours. If there is presence of yellow color colonies, it is concluded as Vibrio spp. 3.12.4 Species Verification by Sub-culturing at 4°C using SWC agar media The pure culture of Bioluminescent bacteria was streaked on the agar media and refrigerate at 4°C. The Photobacterium phosphoreum will exhibit slow growth at
All three smears were viewed under the oil immersion lens (x1000) (3). The use of oil immersion as opposed to lower magnification allowed the organisms to be viewed more clearly and determine certain characteristics of each bacteria due to the color that appeared under the microscope. The gram stain of Micrococcus leuteus (Figure 1) was gram-positive due to the purple color after being stained. The gram stain of Serratia marcescens (Figure 2) was gram-negative due to the pink color after being stained. The gram stain of M. leuteus, S. marcescens and Escherichia coli (Figure 3) was both gram-positive and gram-negative, because S. marcescens and E. coli are gram-negative (4), and M. leuteus is gram-positive.
The agent used was called tetramethyl-p-phenylendiamine. When reduced the agent was clear but when oxidized it turned deep purple to a blackish color. This agent (Cytochrome C Oxidase) was the electron donor. This test did not distinguish whether the organism is oxidative or if it fermented. In the Oxidative fermentation tube the media was a differential media that helps determine whether specific bacteria can oxidize or ferment to metabolize glucose.
This process was repeated for the all antibiotics with aseptic technique being used. The plate was incubate with lid up on the bookshelf at room temperature for 48 hours. After 48 hours, I observed different growth patterns around the disks. I measured the zone of inhibition of each antibiotic and document them on Microbiology task 3
Biochemical tests are the tests used for the identification of bacterial species based on the differences in the biochemical activities of different bacteria. Bacterial physiology differs from one species to the other. These differences in carbohydrate metabolism, protein metabolism, fat metabolism, production of certain enzymes and ability to utilize a particular compound help them to be identified by the biochemical tests. Gram’s stain was originally devised by histologist Hans Christian Gram in 1884. Gram-positive bacteria stain purple, while Gram-negative bacteria stain pink when subjected to Gram staining.
MATERIALS AND METHODS Bacterial strains and culture conditions Two S. aureus strains were used in the present study; S. aureus 8325-4 (SigB-) and SH1000 representing a SigB+.strain. Overnight cultures were grown in Luria Broth (LB) at 37°Cwith shaking at 150 rpm. Exposure to antibiotics was carried out as detailed below. Antibiotics Ciprofloxacin were purchased from Sigma-Aldrich CO. 10 mg/ml stock solution of antibiotic were prepared freshly with 0.1N HCl and stored at -20°C. During the experiment we diluted with sterile water 1:10 and 1:100 depending on the different drug concentration.
Idoine reduced into idoine ion ， which changre from brown to colourless. In test tube F, the iodine solution change from brown to purple . It is because the salt has a function of cofactor which will shorten the time for amylase to take to break down the
The media used in this experiment was Trypticase nitrate broth. The reagents used (A and B) were sulfanilic acid and alpha-naphthylamine (respectively). Using aseptic technique, the bacterium (16A and 16B) were inoculated into labeled broth test tubes. The tubes were incubated for 48 hours at 37 degrees Celsius. When the incubation was complete 5 drops of reagent A and 5 drops of reagent B were added to each of the broths.
Abstract The transformation principle suggests that bacteria use DNA as their genetic material and are able to exchange their genetic material via a process of transformation. Griffith had theorised the concept of the transformation principle using two strains of bacteria and studied their ability to recombine. Avery and MacLeod followed his studies and suggested DNA was sensitive to DNase, and that the enzyme would destroy the bacteria's ability to exchange genetic material and transform into a new strain. This was then tested in the labs at Wits by second year students where they studied the transformation of ampicillin sensitive E. coli to ampicillin resistant E. coli. The results obtained there were similar to those of Avery and MacLeod,
As well as being able to successfully grow and reproduce, the E. coli in the LB/amp/ara +pGLO plate also emitted a fluorescent glow when exposed to UV light. This can be explained by the examining the medium in which they were grown in. The bacteria were transformed with the pGLO plasmid which contained the GFP and resulted in glowing bacteria, however, in order for this to occur the arabinose C sugar must be present in the medium. This sugar is responsible for the activation of the GFP6. Recall that in the E. coli cells in LB/amp +pGLO plate were also transformed but did not express the fluorescent glow.