Therefore, different methods of staining exist to be able not only to see but also to differentiate bacteria. You can focus on the form, elevation, margin, surface, optical characteristics and pigmentation of your culture to describe it.
A Gram stain was then carried out to differentiate the unknown samples.
The Gram stain produced satisfactory results with a clear indication that the yellow species was Gram positive and the red species was Gram negative.
You might be starting to guess a phylum but you need to perform additional tests to know more about your cell.
Cells are treated first with carbol fushin which is heat-fixed, then with acid alcohol which decoulorize all cells except acid fast bacteria and finally with a counterstain methylene blue.
A stock broth culture of the two unknown species 72 was obtained. Once established, complete eradication of the organism is often difficult, but can be accomplished by application of a bleach-based disinfectant. Unfortunately, a lot of bacteria have very common colonies round, flat and white or creamy white and this test is not enough to identify with certainty a species.
Identifying your unknown You now have a lot of informations about your species. Anaerobic jar Source Respiration The next step to determining which bacteria you have is to know if it's aerobic or anaerobic. The Voge-Proskauer tests shows the production of acetoin.
This test is positive for Escherichia coli and Proteus vulgaris but negative for Enterobacter aerogenes for example. Anaerobic bacteria will grow everywhere in the medium, facultative anaerobes will grow everywhere with a preference for the top of the medium and aerobic bacteria will grow only at the top of the medium where there is still oxygen present.
The reagent used is potassium hydroxide, a creatine solution. The Identification of two unknown species of bacteria in tube 72 are Serratia marcescens and Micrococcus luteus References: A pure culture arrises from a single cell and thus contains only one type of microorganism.
Kovac's reagent reacts with indole to form Rosindol dye, forming a red color that will rise to the top of the broth culture. The Litmus milk test resulted in no change therefore ruling out all bacteria except for M.
An Oxidase test was performed on the Gram negative bacteria to determine if the bacteria are positive for cytochrome c oxidase. The litmus milk test was performed on both Gram positive and Gram negative bacteria to differentiate bacteria based on various reactions that occur in skim milk supplemented with a litmus pH indicator.
This is used to see whether or not the bacteria have a cell wall as some, like Mycoplasm species, lack a cell wall. It is negative for E. It creates a convection current and kills the cells that might have fallen in it during the manipulation. The area around the burner can be considered sterile.
Once established, complete eradication of the organism is often difficult, but can be accomplished by application of a bleach-based disinfectant. An example of an acid fast bacterial species is Mycobaterium smegmatis. There was separate colony growth that where two different colors one red and one yellow on the streak plate incubated 25C.
The cell wall stain stains, as its name suggests, the cell wall of bacteria. The negative stain uses nigrosin which is an acidic stain.
Biochemical properties continued Another test is whether or not your unknown has an hemolytic reaction. Gram-positive cells, like Staphylococcus aureus, are purple under the microscope and Gram-negative cells, for example Escherichia coli or Neisseria subflava, turn out red. Considered a contaminant in sick patients.UNKNOW BACTERIA LAB REPORT UNKNOWN 36 Introduction The purpose of this lab was to identify two unknown bacteria from a mixed culture.
The reason for identification of unknown bacteria was to help students recognize different bacteria through different biochemical tests and characteristics. Microbiology Unknown and Purpose of Microbiology Essay - Part 3.
Microbiology Unknown #94 The purpose of this report was to identify an unknown bacterium by applying methods that were previously learned and conducted in microbiology lab class - Microbiology Unknown and Purpose of Microbiology Essay introduction.
The Identification of Two Unknown Species of Bacteria in Tube #72 Introduction: There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics.
Identifying an Unknown Bacteria Essay.
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Identification of Two Unknown Bacteria ; Microbiology Laboratory Report. Identifying Two Unknown Species of Bacteria Essay - Identifying Two Unknown Species of Bacteria Materials and Methods Week 1, Day 1 (10 November ) The first day an unknown sample was assigned to each group of students.
The first test applied was a gram stain to test for gram positive or gram-negative bacteria. 1 Identification of Two Unknown Species of Bacteria by Anna Albrecht (Microbiology ) Introduction axonomy is defined as ―the science that studies organisms in order to arrange them into.Download