...your unknown wisely” were the words that our instructor used when we were picking our unknown bacterial microorganism. Each person was paired with another member of the class, and was expected to work as a team to figure out the unknown that was chosen. Using steps and experiments from the Bergey’s Manual, we were suppose to figure out the unknown and how the bacteria we had chosen was classified and characterized. My hypothesis when first starting the test was that this unknown was going to be something we had already dealt with in class. I thought our unknown would be Escherichia coli. Materials and Methods When we chose our unknown bacterial microorganism, it had the number one on the side. The broth had a one in turbidity on a scale from one (being the lowest) to four (being the highest). To see more clearly in the tube, swirling was used for sediment to be seen. The first experiment we did was testing the unknown to see if it was a gram-negative bacterium or whether it was a gram-positive bacterium. Majority of the bacteria that had been handled with in class fell under gram negative. How to tell whether the bacteria is gram negative or gram positive is by staining the bacteria and watching it change it’s color. If the bacteria turn purple, that would show that the bacteria are gram-positive. If the bacteria turn red, then that would...
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...gained information can be used to identify bacteria. A scientist by the name of David Bergey was the first person who proposed the system of bacterial classification in which bacteria are grouped according to Gram reaction, metabolism, and morphology. The first edition of Bergey’s Manual of Systematic Bacteriology was published in 1984. This book can be used to identify a microorganism. The purpose of this experiment is to identify an unknown bacteria using the skills learned in microbiology laboratory this semester. Materials and Methods This experiment was conducted at Louisiana State University in Shreveport...
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...species name, in Latin. By having a universal method of identifying bacteria allows for all scientists from any part of the world to identify the same species in an identical manner allowing for a precise of classification. Bacteria are distributed throughout the world in almost every conceivable habit. Bacteria are unicellular microorganisms, with variable shapes and nutritional needs. They lack a distinct nucleus and occur singly or in chains or clusters and form distinct colonies. Bacteria are classified on the basis of many characteristics. Morphological and physiological features such as cell shape, motility, formation of spores and other distinguishable structures, and reaction to Gram stain is a good start in identifying bacteria. Other staining techniques such as Acid Fast stain are also useful in determining species. More important in identification of a genus and species of bacteria are biological tests, including the determination of the types of nutrients a cell can use, the products of its metabolism, and the response to specific chemicals. Other factors that can assist in identification of bacteria are their ecological habitats and more advanced methods such as genetic and molecular composition. Using various techniques one is able to distinguish and ultimately assign then genus and species of the unknown bacteria. Methods: Gram Staining: The Gram stain separates bacteria in two distinct classes and is also useful in distinguishing morphology...
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...Introduction Bacteria are microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. They are remarkably adaptable to diverse environmental conditions and are found in bodies of all living organisms and on all parts of the earth. The purpose of microbial biochemical tests is to identify the unique traits it yields and with that knowledge we can then categorize them in groups and specify them by scientific name. These experiments included the Triple-sugar iron agar (TSIA), Sulfur Indole Motility (SIM), Methyl Red (MR), Voges-Proskauer (VP), Citrate, Urease, Gelatin, and Oxidase Test. In order for these tests to produce reliable and credible results, the bacterium organism must be grown using strict and meticulous procedure to produce viable colonies of pure culture. Having pure culture is significant to ensure that a single type of bacteria is used for identification without contamination so tests can be run without complications or confusion. Once all these tests are performed, the unknown bacteria in this lab will be one of the following: Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, or Salmonella typhimurium. This report included the results and details to these experiments which are discussed further on. Abstract Gram negative bacteria Unknown #12 was run through an array of tests which produced positive and negative results. The results obtained from the various...
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...Systematic Methodology used in the Identification and Isolation of Escherichia coli and Bacillus cereus from an Unknown Culture. By: Richard Martinez MCB-2010L Microbiology Lab Dr. James Rogers 11/29/13 Unknown bacteria were determined to be Escherichia coli and Bacillus cereus due to their morphological, physiological and metabolic properties. I. Abstract In a laboratory setting, it often becomes necessary to identify an unknown organism. In this experiment, researchers classified some unidentified bacteria based on their physical structure, colony morphology, optimal conditions and metabolic properties. A Gram stain using crystal violet, iodine, and safranin and a simple stain using methylene blue characterized the organism’s cell walls. Cultural behaviors were classified by inoculating the organisms onto nutrient agar and incubating them at 30° and 37° C for 48 hours, and observing their behaviors, as well as using Mannitol and phenol red media for fermentation and acid production. Optimal growth temperatures were determined by incubating nutrient agar plates of the organisms at 30° C and 37° C. The metabolic profile was created by inoculating the bacterium into broths containing lactose, mannitol, and citrate and incubating the tubes at 30° and 37° C for 48 hours, then observing them for color change. The stains revealed that the bacteria were both Gram-negative and Gram-positive bacilli. Organism “A” was shown to not grow on MacConkey agar and to have...
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...Determination of Two Unknown Organisms From Sample number 16 Intro: This was an experiment to identify two unknown organisms from sample number 16. The importance of this experiment is to identify two differential bacteria that are commonly found in the world and in the presence of everyday life. Considerations of organisms that could be in the unknown tube include, but not limited to Bacillus subtilis, Clostridium sporogenes, Serratia marcescens, Micrococcus roseus, Micrococcus luteus, Sarcina lutea, Staphylococcus epidermidis, Alcaligenes faecalis, Pseudomonas fragi, and Escherichia coli. The goal of this experiment is to use scientific method by demonstrating proper lab techniques, observing and collecting data, then analyzing results to...
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...Unknown bacteria determined to be Alcaligenes faecalis because of its morphological, physiological and metabolic properties. In a laboratory setting, it often becomes necessary to identify an unknown organism. In this experiment, researchers classified an unidentified bacterium based on its physical structure, colony morphology, optimal conditions and metabolic properties. A Gram stain using crystal violet, iodine, and safranin and a simple stain using methylene blue characterized the organism’s cell wall. Cultural behavior was classified by inoculating the organism onto nutrient agar and incubating it at 37° C for 48 hours, and observing its behavior, as well as using SIM medium to test for motility. Optimal growth temperature was determined by incubating nutrient broths of the organism at 25° C and 37° C, and optimal pH was tested by inoculating broths with pHs of 3, 7, and 10. Fluid thioglycollate medium determined the organism’s oxygen requirements. The metabolic profile was created by inoculating the bacterium into broths containing glucose, lactose, mannitol, and citrate and incubating the tubes at 25° C for 48 hours, then observing it for color change. Oxidative metabolic tests for oxidase and catalase were also performed using an oxidative reagent and hydrogen peroxide, respectively. The Enterotube II System was used to further classify its metabolic profile. The stains revealed that the bacterium was a Gram-negative bacillus. The organism was shown to be non-motile...
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...The goal of this experiments is to observe the relative trends of bacteria growth over time in broth. This experiment was conducted over the period of two days by observing the growth of bacteria in an agar broth. This solution was created by taken a single bacteria colony from a petri with an inoculation loop and placing into a bottle filled with an agar broth. After this, the bottle was placed in a incubator and left there for 24 hours. On day one, the bottle's Absorbance was measured using a spectrophotometer and it was discovered that after twenty minutes the Absorbance raised .01 from -.01. On day two, the bottle's absorbance was measure approximately 24 hours after placing the bottle in the incubator, after measuring the absorbance, it was discovered that the solution had an absorbance of .43 highlighting the grow of the bacteria over the allotted time period. Ultimately, this evidence supports the fact that in a bacteria friendly environment with plenty of food bacteria will multiply at an exponential growth giving the correct environment. If the agar broth containing the bacteria was left to grow for another week or so, it will increase exponential until the food source is depleted or the waste products increase so much that it makes the agar solution toxic and ultimately decreasing the bacteria populous until there is either a small amount of bacteria or none at all do to the lack of food or toxic environment....
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...In this experiment we were able to use the technique of Gram staining to differentiate two types of bacteria that were unknown. Gram staining is a method that is used by many scientists in order to identify unknown bacteria’s via the unique physical and chemical characteristics of their cell walls. In a gram test a bacteria can either be gram positive or gram negative. The Gram-positive bacteria have an intricate set of amino sugars which we call peptidoglycan that form a thick cell wall around the plasma membrane. On the other hand, Gram-negative bacteria have an uncomplicated cell wall which thus has less peptidoglycan. The main source of identification within the Gram test is the fact that Gram-positive bacteria appear blue-purple while Gram-negative bacteria appear pink (Gram Stain). Bacteria can come in one of three different shapes; spirilla (spiral-shaped), cocci (round-shaped), and bacilli (rod-shaped). In order to be able to see these shapes a bacteria must be stained or dyed. I hypothesis that we will have one Gram-positive culture and one Gram-negative culture. (Lab Manual) In order to prepare this lab experiment we performed five steps. The first step in preparing this experiment was to heat fix a bacteria culture sample which in return stopped the sample from coming off the slide during the experiment. In order to perform this first step we first turned on a Bunsen burner and set the flames to a blue color which was used to sterilize an inoculating loop. Next, a...
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...Process and Techniques of Finding Unknown J Abstract: As part of a focal study within Microbiology, many scientists have endeavored to identify the many species and types of microbes found in different environments. In an effort to categorize, understand and distinguish one microbe from another, scientists developed tests to show unique characteristics of microbes. This experiment enlists these tests, such as PCR, Simple and Gram staining, anaerobic growth tests, IMViC, Catalase, Oxidase, selective and differential media to identify an unknown microorganism. The Unknown organism studied was labeled “J” and found to be a gram negative, rod shaped bacteria that does not produce endospores. The selective and differential agars produced no growth on the MSA agar plate showing that the bacteria did not favor a salty environment of the Mannitol salts and showed an acidic by product in the selective and differential media of MacConkey’s Agar. The bacteria showed to metabolize sugars but did not produce any gaseous byproducts. After 16s rRNA was processed and run through a PCR, electricphoresis was used to run the RNA out on a gel in order to sequence the RNA which was then compared in a database. Furthermore, the Unknown J did not produce or metabolize starch. The bacteria did not react with the Citrate, KEY oxidase. When compared to other known bacteria tested, unknown J proved to be Escherichia coli. Introduction: Identifying bacterial causes for certain diseases that have...
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...organisms that cannot be seen without the use of a microscope. The microorganism can be categorized as eukaryotes for instance plant, animal, protozoa, fungi and they can also be grouped into prokaryotes such as bacteria and archaea. This paper will focus on how to identify an unknown bacterium. Bacteria which is also known as the bacterium is a non-cellular microbe that lacks membrane organelles, nucleus, and cell walls. Although bacteria are very small, they have a large diversity and they are different in shapes and sizes. Bacteria have three shapes which are bacilli (rod) shaped, cocci (round) shaped and spirilla (spiral) shaped. The...
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...Abstract In this experiment an unknown gram-negative sample was obtained randomly to identify the possible microorganisms. Using comparative analysis several biochemical tests were performed to determine which bacterium out of the six potential unknowns was given. The biochemical tests carried out included; triple-sugar iron agar (TSIA), sulfur indole motility (SIM), citrate, urease, gelatinase, methyl red (MR) and voges-proskaeur (VP). In order to determine the microorganism characteristics the sample was first isolated using a t-streak and the colonies were gram stained to reveal its shape and morphology and then inoculated into several sequences of media corresponding with the proper biochemical test. After allowing the corresponding time for each biochemical test, data was collected to determine the unknown bacteria. The broth culture in this experiment was determined as Escherichia coli. Introduction All organisms are divided into three domains; bacteria, archaea, and eukarya. The organisms making up domain Bacteria and domain Archaea are all prokaryotes. Although bacteria and archaea look the same, archaea is more closely related to eukarya (Madigan et.al 2009). The ability to adapt to a broad range of habitats helps to explain why prokaryotes are the most abundant organism on earth. The main characteristics of a prokaryote include, no nucleus, circular DNA, and no membrane bound organelles. A key feature of nearly all prokaryotic cells is the cell wall, which maintains...
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...have certain bacteria that are considered good bacteria and therefore treating an infection with a selectively toxic agent would preserve the healthy bacteria in our body. B. Broad spectrum antibiotics are effective in inhibiting growth in a wide variety of both gram-positive and gram-negative bacteria. Such antibiotics are very important when time is limited in determining what kind of bacteria is causing a life-threatening infection. They are also beneficial when the exact bacteria that is causing the infection is unknown. Also, some infections are not just caused by one type of microorganism. However, there are certain types of bacteria that have developed resistance to broad spectrum antibiotics. Narrow-spectrum antibiotics are effective against killing just gram-positive or just gram-negative bacteria. They target the bacteria that is causing the infection while not killing as many or any of the normal bacteria. These antibiotics also cause less resistance to the bacteria. A disadvantage of narrow-spectrum antibiotics is that they can only be used to treat an infection in which the bacteria that has caused it is known. C. Certain enzymes may cause inactivation of antibiotics which causes resistance to antimicrobial agents. The bacteria’s target site may change in some way which reduces the effectiveness of antimicrobials. Certain bacteria are able to neutralize the agent and even prevent the agent from getting into the bacteria. Some bacteria may become...
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...Free 866.206.0773 A Laboratory Manual of Small-Scale Experiments for the Independent Study of Microbiology 50-0222-MB-01 LabPaq® is a registered trademark of Hands-On Labs, Inc. (HOL). The LabPaq referenced in this manual is produced by Hands-On Labs, Inc. which holds and reserves all copyrights on the intellectual properties associated with the LabPaq’s unique design, assembly, and learning experiences. The laboratory manual included with a LabPaq is intended for the sole use by that LabPaq’s original purchaser and may not be reused without a LabPaq or by others without the specific written consent of HOL. No portion of any LabPaq manual’s materials may be reproduced, transmitted or distributed to others in any manner, nor may be downloaded to any public or privately shared systems or servers without the express written consent of HOL. No changes may be made in any LabPaq materials without the express written consent of HOL. HOL has invested years of research and development into these materials, reserves all rights related to them, and retains the right to impose substantial penalties for any misuse. Published by: Hands-On Labs, Inc. 3880 S. Windermere St. Englewood, CO 80110 Phone: Denver Area: 303-679-6252 Toll-free, Long-distance: 866-206-0773 www.LabPaq.com E-mail: info@LabPaq.com Printed in the United States of America. The experiments in this manual have been and may be conducted in a regular...
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...Motility Testing Cynthia Alonzo, M.S. Version 09-2.01 Read the entire experiment and organize time, materials, and work space before beginning. Remember to review the safety sections and wear goggles when working with chemicals. Objectives: To learn flagellar structure and arrangements common in microbes, and To use direct observation and testing to determine if a given microbe is motile. Materials From: Label or Box/Bag: Qty Item Description: Student Provides 1 Microscope 1 Paper Clip 1 10%-bleach Solution 1 Paper towels From LabPaq 1 Gloves packages - 11 pairs 1 Immersion Oil 1 Slide - Cover Glass - Cover Slip Cube (4) Culture Media Bag #2 - Refrigerate upon Receipt Culture Media Bag #2 - Refrigerate upon Receipt 2 Agar, 0.4% Motility Test Agar - 8 mL in Glass Tube Inoculation Instruments Inoculation Instruments 1 Inoculation Loop, Plastic Mask Bag Mask Bag 1 Mask with Earloops (11) in Bag 5" x 8" Slide Box MBK Slide Box MBK 1 Slide-Box-MBK with Blank-Slides (4) Pre-Lab Preparation: Place saved cultures of E. coli and S. epidermidis (from previous lab) in incubator 12-24 hours prior to the start of the experiment. Discussion and Review: Many bacteria are capable of motility, the ability to move under their own power. Most motile bacteria propel themselves by special organelles termed flagella. The bacterial flagellum is a noncontractile, semi-rigid, helical tube composed of protein and anchors to the bacterial cytoplasmic membrane...
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