Throughout the urea cycle, the amino acid, arginine, is changes into ornithine- this is another amino acid when hydrated, that is when water was added. During this reaction, urea is the product formed (Nelson and Cox 2008). Figure 1 shows the urea cycle, occurs specifically in the mitochondria and cytosol in the liver. (Nelson and M.Cox 2008). Urea is made in the liver by means of enzymes in the urea cycle.
Following are the tests used for the identification of bacterial species based on the differences in the biochemical activities of different bacteria. Beta glucouronidase test is used for the identification of Escherichia coli. An enzyme is produced by E.coli which is beta D glucouronidase. Beta d glucouronidase in turn hydrolyzes beta d glucopyranosid uronic derivatives to aglycons and D glucuronic acid. Bile solubility test is used in laboratory for differentiation of alpha hemolytic Streptococci from Streptococcus pneumoniae.
Differential organisms require different nutrients which show it is fairly easy to isolate and identify organisms by using selective media. Differentiation media are also used by taking advantage of whether an organism produces acid or not. MacConkey agar is an example of a differential media which will enable the organism to express a colour depending on whether it produces acid. This agar contains a pH indicator which can provide more information on the type of bacteria that is growing on the agar. Method
2. You have been asked to set up a dilution series, and then use spread plates to determine the viable cell count. Why is it necessary to use a dilution series when isolating bacteria from a biological sample using spread plating? [5 MARKS] It is vital to use a dilution series to reduce the concentration of the original biological sample so it is easier to count the number of isolated colonies which are present on the spread plate.
• Serine, threonine and cysteine proteases use a nucleophilic residue (usually in a catalytic triad). That residue performs a nucleophilic attack to covalently link the protease to the substrate protein, releasing the first half of the product. This covalent acyl-enzyme intermediate is then hydrolysed by activated water to complete catalysis by releasing the second half of the product and regenerating the free enzyme. A comparison of the two hydrolytic mechanisms used for proteolysis. enzyme is shown in black, substrate protein in red and water in blue.
The secondary antibody (anti-rabbit HRP labelled) used is conjugated with an enzyme Horse radish peroxidase which then binds to its substrate tetramethyl-benzidine (TMB) to produce a blue color indicating the presence of lysozyme. SDS-PAGE gel electrophoresis is a process which separates proteins based on molecular weight. The purpose of this method is to separate out the lysozyme by its weight. The weight is known to be 14.6Da. To view the protein separation, the gel was placed into coomassie blue to develop a series of bands to detect the protein by its
In this lab, the quantitative assay that was constructed was a plaque assay. A plaque assay is a modification of a bacteriophage assay and is used to estimate the titer (concentration of a solution) of a phage stock. A plaque assay contains a virus combined with bacterial cells on the surface of an agar plate. The agar plate inhibits the spread of viral progeny to neighboring bacterial cells which results in plaque formation (lysis of bacterial cell). The purpose of this lab was to perform a bacteriophage assay and to calculate the original stock titer of the phage stock using the known set of dilutions and direct plaque count.
Extracellular matrix (ECM) comprises of variety of proteins like collagen, fibronectin, laminin along with mucins. Lactobacillus has an array of proteins which specifically binds with ECM proteins and further mediating adhesion of cells to mucosa layer in
Chemical transformation, electroporation or particle bombardment is the typical method of construct into a host cell. Conjugation: The easiest illustration is to consider this as a version of bacterial sex. In conjugation the two bacterial cells connect, and the male donates a piece of DNA to the female. The piece of DNA was excised from a bacterial chromosome. The pieces are called plasmids.
The Role of Iron in Human Nutrition Structure, Function and Metabolism of Dietary Iron Iron is a trace element, which is a group of minerals present in small quantities in the body. Other trace elements include copper, zinc, selenium, manganese and iodine. These minerals cannot be synthesized by the body and must therefore be supplied in the diet. Iron is the most common trace element in the human body; adult males have approximately 3.5 g iron in total, or 50 mg per kg body weight while females have about 2g total iron or 35 mg per kg bodyweight. Iron can exist in oxidation states from -2 to +6, but mainly exists in the ferrous (+2) and ferric (+3) states in biological systems.
After a great deal of research, it was revealed that in individuals that were infected with Helicobacter Pylori, antibodies were found in the bloodstream. Helicobacter Pylori are able to attach to cells as they go through the mucous layer of the stomach. When the bacterium enters the stomach, an enzyme called urease converts the stomach cells chemical urea into ammonia and carbon dioxide. The enzyme urease tends to trigger inflammation.
Inducers bind to the repressors and they also regulate gene expression. In the process of identifying the three strains of E.coli, ONPG (ortho-nitrophenyl b-D galactoside) was used as an indicator. ONPG is a substrate that can detect B-galactosidase, and when it does, it turns yellow. Sarkosyl was also a detergent used in the lab to lyse open cells. In the lab we predicted that the E.coli wild type would be clear for distilled water and sucrose but yellow for lactose.
Catalase activity test establishes whether the bacterium produces the enzyme catalase. The eosin methylene blue test or EMB, inhibits the growth of gram positive bacteria and tests whether or not gram negative bacteria can ferment lactose. Lactose fermentation testing is done to see if the bacterium is capable of fermenting sugar by testing for acid and gas production. These are the possible tests that are needed in order to identify unknown
Of the Enterobacteriaceae family, there are genera that are in the normal human flora. Some species such as K. pneumoniae and E. coli are opportunistic pathogens which can capitalize on weakened host defenses and cause food poisoning (Baron, 1996). S. enterica secrete proteins that help aid in intracellular invasion and proliferation (Hensel, 2009). K. pneumoniae is a part of the normal human mouth, skin, and intestine flora, but can wreak havoc if inhaled (Ryan,