Figure 3. Testing of transformed and mutant bacteria on minimal medium Growth was observed on the Transformed (Trsf) section and not on the Mutant (Mut)
Introduction The Lab 18 focuses on the reaction rates. Each experiment will have two or more test tubes with same amount of reactants to be included. However, the different variable will show the difference of how reaction can be hastened or delayed. The different variables are temperature, concentration, and presence of catalyst.
Introduction: The Assabet river is a well known river that runs through Westborough, Northborough, Marlborough, Berlin, Hudson, Stow, Maynard, Acton, and Concord, MA. The river is about 34 miles long and is home to many aquatic animals and plants. The plants range from Chiliensis to Anubias, and they grow around the borders of the river. The Assabet river has different water temperatures, depending on the location. The purpose of this lab is to determine whether or not the Assabet river temperature affect the plants near and in the river.
Hypothesis If E coli bacteria is added to all four agar plates, then both of the agar plates labeled +pGLO and the -pGLO plate without ampicillin would grow. Variables The independent variables in this experiment is the addition of pGLO, ampicillin, and arabinose. The dependent variables in the experiment are whether or not bacterial growth occurs, or if the bacteria grow. The constants in the experiment are the size of the agar plate, the temperature in which the agar plates incubate, and the length of time the
The presence of nitrate reductase also came back positive, this implies that the microbe is capable of reducing nitrate to nitrite. The catalase displays that the bacteria is able to break down the toxic forms of oxygen as well. However, the Oxidase test indicates that the microbe is unable to produce cytochrome c oxidase. The MR-VP test shows that the bacteria can carry out mixed acid fermentation when supplied with glucose but is incapable of 2,3 butanediol fermentation after the following mixed-acid fermentation. The tryptophanase test indicates that the bacteria is unable to synthesize tryptophanase in order to produce indole.
It has the shortest reported generation time of any organisms, approximately 6.3 minutes in thioglycollate medium. Virulence factors of the causative agent: C. perfringens can survive in high temperatures such as 54-140 degrees Fahrenheit. The spores quickly germinate causing the bacteria to grow. This bacterium grows the quickest at temperatures such as 109-117 degrees Fahrenheit. If the food is served without reheating to kill the bacteria, live bacteria may be consumed.
Discussion: Since the plate represented by Figure 1 does not contain plasmid, there will not be any transformed cells. There is also no antibiotic ampicillin, therefore the cells will not die but they will grow and replicate since it is on the LB agar plate. Therefore on this plate there are only the normal E.coli cells. The LB agar plate is a favorable environment for the bacteria to grow and replicate at its optimum rate (Sezonov, 2007).
Oxygen - Almost all food-borne pathogens are aerobic. Some microorganisms thrives in oxygen, and some reproduce when the environment lacks oxygen. Moisture - Water is essential for the growth of food-borne pathogens; water activity (aw) is a measurement of the water that is available for use and is measured on a scale of (0 to 1.0). Food-borne pathogens grow best in the foods that have an aw level between 0.95 and 1.0. FDA regulations for canned foods require food with aw levels of 0.85 or below.
Microbiology is interesting. In the article it states,” I Strongly believe that Microbiology is the most interesting subject ], blended with many interesting funny small creatures which are invisible to the eyes of humans.” In other words, Would Mouth Bacteria Grow Better in Room Temperature or in a Refrigerator at a Colder Temperature? Hypothesis If mouth bacteria is in the refrigerator, it won’t grow as fast as the mouth bacteria in room temperature because mouth bacteria like warmer temperature better than colder temperature and the cold temperature would freeze the agar gel so the bacteria won’t be able to eat.
But considering how fast cross-contamination could occur if the bacteria were to have direct contact with air, it was better to use nutrient broth to grow E. coli in the calibration with known pH
Listeria Bacteria found in the Listeria genus are Gram-positive, flagellated, rod shaped bacteria found in several places. For instance, water, soil, and animals like cattle. The Listeria genus has the special and uncommon ability to survive and grow in severe environments, including freezing temperatures. The optimum temperature for Listeria to grow is 30 degrees to 37 degrees Celsius. (Holt, Krieg, Sneath, Staley, & Williams, 1994)
As thousands of types of bacteria are naturally present in our environment. These microorganisms that cause disease are called pathogens and when certain pathogens enter the food supply, they can cause foodborne illness. However, most cases of foodborne illness can be prevented with proper cooking or processing of food as this will destroy the pathogens. Another way to prevent it is by “keeping cold foods cold and hot foods hot”, doing this will prevent the bacteria from rapidly proliferating because bacteria tend to multiply quickly between 40 °F and 140
Bacteria is a member of a large group of unicellular microorganisms that have a cell wall but lack organelles and an organized nucleus, including some that can cause disease. Bacteria can be found in meat, poultry, seafood, eggs and dairy products in particular. In his book The Microbiological Safety of Low Water Food and Spices, Joshua Gutler states that “Historically, the low-water activity or low moisture content of foods has been considered a significant barrier to the growth of human foodborne pathogen, bacteria, hence, such foods have often been inappropriately assumed to be microbiologically safe” (1). Bacteria multiply rapidly between forty degrees and one hundred and forty degrees Fahrenheit. To keep food out of the “Danger Zone” keep cold food cold and hot food hot.
It’s also highly motile bacteria which can move by unipolar or bipolar flagella Moreover, Campylobacter are able to grow between 37-42 C, but they can’t grow below 30°C and survive poorly at room temperature. However, Freezing–thawing it can decrease the population of Campylobacter spp. It was found that freezing does not remove the living organism from contaminated foods .They are fragile organism which are sensitive to some conditions such as dry, freezing, reduced pH and does not have the ability to survive below a pH of 4.9 , but the optimal growth at pH 6.5–7.5. These non-spore-forming organisms are essentially microaerophilic, growing best in an atmosphere with low oxygen concentration (5% O2, 10% CO2). Basically, Campylobacters have many species such as C.jejuni and C.coli but the most commonly cause food poisoning is C.jejuni.
Warmer water is a breeding environment for bacteria to
