Agar Lab Report

Then, the polypeptides are further converted into amino acids. The bacterial cells can then take up these amino acids and use them in their metabolic processes. Gelatin hydrolysis test is helpful in identifying and differentiating species of Bacillus, Clostridium, Proteus, Pseudomonas and Serratia [171]. Hydrogen sulphide (H2S) production test is used for the detection of H2S gas produced by an organism. It is used

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.

Nutritions, temperature, oxygen, pH, microbial products and antagonistic and synergistic effects are determinant factors which predispose the condition of residue of cutaneous normal flora populations. The ability of enzymes secretions in microorganisms is another factor for their colonization on the surface of the skin; because the presence of microbial extracellular enzymes on the human skin makes a wide range of nutrition accessible for microorganisms (12,

In the Oxidative fermentation tube the media was a differential media that helps determine whether specific bacteria can oxidize or ferment to metabolize glucose. Citrate test checks to see which bacteria could citrate as the only source of carbon. A positive test shows that an alkaline environment ia created and that the pH level rose. The color of the media changed from green to blue if its positive. The Bile Esculin agar test has its medium as selective and differential.

The next step is bacterial invasion or invasion by pathogenic products into the periodontal tissues, interactions of bacteria or their substances with host cells, and this directly/indirectly causes degradation of the periodontium, resulting in tissue destruction. As a Microbial Habitat, the mouth provides a warm and moist environment that suits the growth of many microorganisms. The mouth is the only site in the human body that normally provides non-shedding surfaces for microbial colonization; this facilitates the development of thick biofilms, particularly at stagnant sites. Thus, in this way, the host provides unique opportunities for biofilm formation in the mouth, and a secure haven for microbial persistence. Oral environment determines the constituent species of dental biofilm and the variation between individuals.

.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 at 370C The diameter of the clear zone was measured. Fig 9: Agar disk diffusion 5.5 Time Kill Assay The basic concept of the Time-Kill Kinetic study is establishment of the rate at which a microorganism is killed by a product as a function of survival

3.12.2 Oxidase Test On a filter paper or cotton bud, pick the desired colonies from the agar plate. Then, using a dropper, take the oxidase reagent and drop it on to the filter paper and observe for colour changes. The blue colour appearance indicates positive reaction whereas if there are no changes, then it’s a negative reaction. 3.12.3 Genus Verification using TCBS agar The TCBS medium, known as Thiosulfate Citrate Bile Salts Sucrose Agar is a recommended selective medium which allows the growth of bacteria belonging to the genera Vibrio. TCBS agar was prepared for about 100ml and poured into petri plates, after solidifying, pure colonies of bioluminescent bacteria was streaked.

It favors the skin, since it is part of the normal flora. Its virulence factor comes from multiple things within the cell and these things contribute to the types of infections they cause. Two important virulence factors are a secreted protein called coagulase and clumping factor. Some other virulent factors are the capsule, enterotoxins, exfoliatin, toxic shock syndrome toxin, and alpha toxin. The enterotoxins cause food poisoning in humans.

Inducing Prodigiosin Transposon mutagenesis in Serratia Marcescens Introduction Serratia Marcescens is an opportunistic pathogen, mainly of healthcare facilities but can also be found in many diverse environments. Serratia is a gram negative bacteria which can give it innate resistance to certain antibiotics, especially those that target peptidoglycan cell wall synthesis, due to its outer membrane. In an environment with different microorganisms competing for food Serratia holds a component that gives it another selective advantage. The bacteria contains a red pigment called prodigiosin, that has antibacterial, antifungal, and even antiprotozoal activity. The pigment is produced due to quorum sensing of bacteria, when an appropriate level of N-hex anoyl-L-homoserine lactone (HHL),

Lacase which is produced by many fungi is used in the making of paper. Enzymes are an alternative to harsh chemicals as they work under moderate conditions, reduce energy consumption and offer minimal risk both to humans and the environment. Vitamin B12 is synthesized by the fungus Ashbya gossipy. Lipases, peroxidases, oxidases together with protease enzymes are used in the manufacture of detergents and biosurfactants that are used as household detergents, industrial cleaners as well as in leather