The gram negative species are apart of the Enterobacteriaceae family. These are gram-negative rods, which are facultatively aerobic - either respiring or fermenting. Most are motile via a flagella (Carson, 2015). Salmonella enterica and Yersinia enterocolitica are both paracolons, which lack the ability to ferment lactose. Conversely, Klebsiella pneumoniae and Escherichia coli are both coliforms, which are able to ferment lactose.
Bacterial transformation is a technique widely practiced by scientists for research purposes. This experiment explored the transformation of E. coli cultures with pGLO plasmids to allow the bacterial cells to express a foreign protein and emit a fluorescent glow under UV light. The transformation was completed through the heat shock method. Both transformed and untransformed E. coli cultures were grown in four mediums. The four mediums were made of different combinations of the LB nutrient broth, ampicillin and arabinose C sugar.
Two of most important reference methods for detection of Listeria in all food samples are: FDA bacteriological and analytical methods (BAM) and International Organization of Standard (ISO) 11290 methods . In FDA BAM methods enrichment carried out in media containing selective bacteriostatic agent (nalidixic acid and acriflavine) along with cycloheximide as antifungal agent. The temperature for enrichment is 30oC for 48hrs. The ISO 11290 is two-step process: first enrichment in half Fraser broth for 24hrs then transferred to full Fraser media. The Fraser media contains the same bacteriostatic agent as in FDA BAM method and also contains esculin for detection of ẞ-D- galactosidase activity of Listeria.
The effects are red bright skin. In lab, we learned to distinguish two types of bacteria using the gram stain, gram positive and gram negative. Since S. Aureus has a thick peptidoglycan cell wall with teichoic acid, it stains gram positive. Further tests will indicate the bacteria, including the presence of catalase, sheep blood hemolysis, mannitol fermentation, halotolerance, and coagulase, which S. Aureus is positive for all. 3.)
Recovery broth was added to the cell suspension, and the bacteria was placed in warm water for about thirty minutes (see Results and Discussion, paragraph 2). This recovery period let the bacteria repair their cell membranes and express the added genes. Lastly, the transformed E. coli were placed on agar plates and allowed to grow overnight. One agar plate only contained nutrients (-DNA), two contained nutrients and ampicillin, (-DNA/Amp and +DNA/Amp), and one contained nutrients, ampicillin, and IPTG, a protein that caused the GFP to express a glow. After completing the lab, it was discovered that the ARG gene creates a resistance to antibiotics, like ampicillin, and that bacteria can take in new genes.
Nguyen Nguyen Professor Microbiology 1 May 18th, 2016 01MW – Staphylococcus Epidermidis The Staphylococcus Epidermidis is classified as bacteria. Scientists reckon it to Firmicutes phylum and adjust it in Bacillales order of Bacilli class. This bacteria belongs to Staphylococcaceae family. As the name order, it is settled into Staphylococcus genus and S. Epidermidis species. S. Epidermidis makes its home on human skin, mucosal layer and nasal mucosa.
The iodine test determines the presence of starch in biological materials. It is predicted that, if starch is not present, the solution with iodine remains yellow. However, if starch is present the solution with iodine becomes a blue-black colour. Plants have starch as the storage polysaccharide (glucose units held together by glycosidic bonds) while animals have the equivalent of glycogen. In this experiment, the dark blue colour is visible because of the helical amylose and amylopectin reacting with iodine (Travers et al., 2002).
Store the petri dish in the incubator Data: Day 1 Dish was spotted with slight growth of bacteria. Each section had a different type/number of bacteria: the table was a variety, the keyboard was all the same yellow dots, the cellphone has a big brown dot, and the bottle had a couple of yellow
In vitro susceptibility tests are done by the following methods: 1) Agar diffusion method 2) Tube dilution method 3) Micro-dilution method 4.3.2 Protocol: Synthesized compounds were assessed for their antibacterial activity using Agar diffusion method. Antibacterial activity of the compounds was carried out against pathogenic bacterial strains namely E.Coli: ATCC 50992 (Gram-ve), Staphylococcus aureus: ATCC 29213 (Gram+ve), Pseudomonas aureginosa: ATCC 27853 (Gram+ve), Bacillus subtilis: ATCC 10231(Gram- ve). The antibacterial activity of the compounds was determined by observing the zone of inhibition in the comparison to standard antibiotic Ciprofloxacin. Test compounds were dissolved in the DMSO to make a stock solution of 1000 ppm (1mg dissolved in 1ml DMSO). The fresh subculture of strains in the normal saline was added to the sterile assay medium (Nutrient agar) at 40-45°C and mixed well.
All of the plates were looked at for the amount of colonies grown, if growth was present, and if the colonies gained the ability to glow green. Transformation was successful in the plates where the bacteria consumed the pGLO plasmid. In the first plate that the bacterium was plated on it included the LB broth and of ampicillin antibiotic (amp), 2 colonies were present. The second plate of bacteria was grown with the presence of LB broth, ampicillin, arabinose sugar (ara), and 22 colonies were observed. But a green fluorescent glow of the colonies was only present in plate 2.