...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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...reference 1. Gram Stain * Verify if bacteria are present or not. * Controls – positive (purple) – S.aureus * negative ( red/pink) – E.coli 2. Endospore Staine Positive controller – B. magneterium Green spore- Positive Pink (vegetative ) – Negative 3. Acid fast Positive control – M. smeagmatis Blue – negative Pink /red- positive 4. Motility Positive control - P.vulgaris A. non motile is negative test B. motile is a positive test 5. Carbohydrates fermentation (test for gram -) ( glucose , manitol, lactose) Positive control – ecoli (yellow) Red- no color change – negative test Yellow – color change – positive test 6. Mae Conkey’s Agar Ecoli – positive control Selective for negative gram stain Differential for organism that could ferment lactase Growth pink – positive No growth – negative 7. Gelatin Hydrolysis ( Gelatinase) Positive control – P.aeruginosa Liquid –positive test Solid - Negative test 8. Blood agar Positive control – S. aureus A. Betahemolysis B. alphahemolysis C. gammahemolysis 9. FTM *broth – O2 relationship with 10. MRVP (mix acid fermentation) MR- methyl red (PH lower than 4.4) Positive control – e.coli red color- positive test no red – negative test 11. Voges Proskauer ( acetone) –precursor for those who fermented butane Positive control- E. aerogenosa Red color – positive test No color change – negative test 12. Nitrate...
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...IgM -gram negative rods,Very small cannot be seen under microscope -Slow grow better isolate with CO2 and increase humidity. -Sampled from blood (5 to 7 days b4 giving a negative report) -cultured on chocolate agar(enrichment media). - Wright test (like widal “ anamnastic reaction” ) Transmitted via contaminated food Milk products not from human to human : can be killed at high temperature: - tantalization : 50º - Pasteurization: 70 º - Sterilization : 100 º Treatment: - Tetracyclin - Doxycyclin - Rifampin - For 6 weeks and more - Vaccine is available for animals. Vibrio V. cholerae, V. parahaemolyticus, V. vulnificus Features: - Gram negative - Fermenter bacilli - Facultative anaerobes - Live in halophilic places Identification: - Enrichment medium - alkaline peptone broth Vibrios survive and replicate at high pH - Other organisms are killed or do not multiply - Selective/differential culture medium - TCBS agar - V. cholerae grow as yellow colonies - Biochemical and serological tests Pathogenesis and treatment: Rehydration & supportive therapy Oral Intravenous (IV): - Doxycycline or tetracycline (Test resistance may be developing) of secondary value - Water purification, sanitation & sewage treatment Vaccines Symptoms: - diarrhea - feces-streaked stool changes: Colorless; Odorless; No protein Speckled with mucus Haemophilus H.influenze (meningitidis); H. ducreyi (chanchroid) Features: - Gram-negative and...
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...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 affected the population or identifying growth on old bread is not new to science. Joseph Lister developed one of the first ways to separate the desired unknown bacteria from other bacterial colonies in 1867. Lister’s aseptic technique, used in both science and healthcare, destroys the microbes that are...
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...MLT1 Experiment 5/Task 6 Differential Staining There are many different ways to stain bacteria for viewing under a microscope. For the most part these are categorized as “either simple, nonspecific or differential (specific) (LabPaq, p.128). The most common staining method used is Gram staining. Gram staining is a differential or specific method of staining. Gram staining is a way to tell the difference between gram positive and gram negative bacteria. The cell wall of the gram positive bacteria is made up of several “layers of peptidoglygan,” and “techoic acids,” (LabPaq, p. 128). This peptidoglycan is what absorbs the color part of the crystal violet stain causing the gram positive bacterial cell to appear violet colored when viewed with a microscope. In contrast, the cell wall of the gram negative bacterial cell is not as thick as that of the gram positive cell wall. Peptidoglygans are on the inside of the cell rather than in outer layers. The outer part of the gram negative cell is made up of phospholipids and lipipoly-saccharides (Betsy and Keough, 2005). The outer cell wall does not hold onto the violet color of the crystal violet and appears pink in color when viewed under a microscope. The purpose of iodine staining is to aid the bacteria to keep the stain by creating an iodine-crystal violet mixture that will not dissolve. Iodine is also known as a mordant in this case. A mordant is usually an inorganic oxide that when mixed with...
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..."NATURAL PRESERVATIVES" Anthony C. Dweck Research Director, Peter Black Medicare Ltd., White Horse Business Park, Aintree Avenue, Trowbridge, Wiltshire, UK. BA14 0XB SUMMARY This paper looks at the theoretical development of a natural preservative system using the author's data base on medicinal plants as a source of references. The legal aspects of this concept are considered. The traditional methods of preservation, many taken from the food industry are summarised. The use of alcohol, glycerine, sugar, salt, dessication, anhydrous systems and temperature are amongst examples considered. The definitions of the many words used to describe the act of preservation are considered, and the confusion that results from the presence of the many synonyms is considered. e.g. antimicrobial, antibiotic, antiseptic, bactericidal, etc. Specific organisms are identified as being of particular interest, especially those standard organisms that form part of the B.P. challenge test. These include Candida albicans, Pseudomonas aeruginosa, Escherichia coli, Aspergillus niger and Staphylococcus aureus. A cross-section of plants mentioned in the literature as being specifically targeted at these organisms are considered. The paper concludes with Appendices of plant materials that have mention in the literature according to specific definitions, which may give researchers a potential introduction to future research. KEY WORDS Natural preservation, traditional preservation, challenge test organisms...
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...HOW TO WRITE AN UNKNOWN LAB REPORT IN MICROBIOLOGY GENERAL Unknown reports in microbiology are written in scientific format. Scientific writing is written differently from other types of writing. The results of the exercise or experiment are what are being showcased, not the writing. The purpose of scientific writing is not to entertain, but to inform. The writing should be simple and easy to understand. There is a specific style that must be followed when writing scientific reports. Scientific writing is typically written in the passive voice. The pronouns "I", "We" and "They" are not typically used.. For example, instead of writing "I used a TSA agar plate to isolate my unknown," it is customary to write, "A trypticase soy agar (TSA) plate was used to isolate the unknown." It is also customary to write in the past tense for most of the report. This includes the introduction, the summary, the description of the materials and methods and the results. The present tense is reserved for the conclusions about the results. See the examples given below. Some other general rules that should be followed are: Microbial nomenclature: The name of the bacterium should written and spelled correctly. The name should be italicized or underlined. Italicized is preferred. For example, Staphylococcus aureus. The genus is capitalized but the species is not. After the full genus name is given in the paper, it can be written as S. aureus, but still italicized. This is as long as there in no other...
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...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. In catalase test it acts as a catalyst for the breakdown of hydrogen peroxide to oxygen and water. Catalase production test is done for an organism by bringing it into association with hydrogen peroxide. If an organism is...
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...Microbiology lab study guide Exam 1 Know step by step instructions on use of microscope to view a specimen (image remains in focus even when changing objective lens – parfocal) * Bright field- Dark image against bright background. * Dark field- Field surrounding the specimen appears black while object is brightly illuminated. * Phase contrast- Specimens appear as various levels of “darks” against a bright background. * Fluorescence- fluorescence dye is used which emits fluorescence under UV light.. * Total Magnification = Magnification by the objective lens X Magnification by ocular lens. * FOCUS MICROSCOPE PROPERLY by starting with scanning lens and moving up each objective, using scope’s parfocal property Know step by step instructions for ocular micrometer calibration using the stage micrometer * Calibration = Stage Micrometer /Ocular Micrometer * Stage Micrometer: mm convert to um * Ocular Micrometer: 0 – 100 Ocular Units * EX: 0.2mm X 1,000 um = 200 um * 1mm * Placed stage micrometer superimposed by the ocular micrometer. * First left line of the ocular micrometer aligned with one of the marks on the stage micrometer * EX 25 of ocular micrometer on 8 major lines of the stage micrometer are perfectly aligned= 800 µm ÷ 25 ocular units = 32 um/OU * Record more than one measurement * Calibrate each magnification * Know the different parts of the microscope...
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...What is the mechanism that Bordetella pertussis uses to invade epithelial cells in the lungs? The bacteria, Bordetella pertussis causes cough which becomes serious cough as the bacteria stays in the upper respiratory track and releases toxins which lead to the inflammation. The lungs consist of the Epithelial cell lining which is invaded by this bacteria. There are two stages for this disease the first stage is the colonization of the bacteria in the upper respiratory track. And the second stage is known as toxemic stage. During the first stage fever, cough is observed and during the toxemic stage there will be prolonged cough. We need to identify in the first stage itself as the medication will be working but the medication will not be working in the second stage. Why does this Gram-negative bacteria cause the characteristic cough that it does? Dry cough and sore throat are the common symptoms which are seen with Gram- negative bacteria. Cough lasts for almost 7-10 days. The Gram negative bacteria enters in to the respiratory track and involves in production of mucous and this results in the excess mucous production due to which cough effects the patient. Respiratory track is blocked by this mucous which leads to the breathing hard and whopping sound is also observed while coughing. Why is infant mortality high? All age groups might be affected with the disease; infants are at the high risk. As vaccination is not done infant mortality rate is high. Booster vaccines...
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...pathogens such as Bacillus subtilis, Streptococcus pyogens, Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Proteus mirabillis and Pseudomonas aeruginosa by paper disc method. The butanolic extract of Abelmoschus esculentus was more active against almost 90% of the organism tested. It was followed by Ethyl acetate, Methanol, Petroleum ether, Chloroform in inhibiting the growth of organism tested. Key Words: Abelmoschus esculentus, Pathogens, Antibacterial assay, Malvaceae, Disc diffusion method INTRODUCTION Many drug resistant bacterial strains were developed due to the increased use of a number of antibacterial drugs. It also created the problem in controlling the growth of infectious disease causing pathogenic bacteria. Moreover synthetic drugs produce side effect to the users1.To circumvent this problem, scientists...
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...an Infected Patient After collecting a sputum sample from a patient that is suspected or may be infected with a bacterium from one of the following genera: Escherichia, Mycoplasma or Bacillus; Each bacteria listed should be isolated by utilizing each of the various staining techniques. The best staining techniques to use is the Gram stain or the Acid- fast stain due to the fact that they both will provide a lot of information in detail regarding the bacteria being studied. It is very important to be observant of how each bacterium obtained reacts to each stain, and how the results obtained will lead us in a developing diagnosis. The first technique being used is the Gram stain. Gram stain is probably one of the most common used staining procedures used in the field of microbiology. It is one of the differential stains that are used to characterize bacteria in one of the two groups: either gram positive or gram negative bacteria. Bacteria prepared for the Gram stain is a heated fixed smear that is covered with a crystal violet. Because the purple stain impart its color to all cells. After a short period of time, the purple dye is then washed off, and the smear is then covered with iodine, a mordant. When the iodine is then washed off, both the gram-positive and gram-negative bacteria appear dark violet in color or purple. The next, process is the slide is then washed with alcohol or an alcohol- acetone solution. This solution is a decolorizing agent, which removes the purple dye...
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...between gram-positive and gram-negative cell walls. The difference is the outer casing of the bacteria. Gram positive cell wall consists of a smooth and thick wall. A gram positive bacteria will have a thick layer of peptidoglycan (a sugar-protein shell) that the stain can penetrate and teichoic acids. In this case the lactobacillus and staphylococcus are gram positive. A gram negative cell wall is wavy and much thinner and has a couple of layers of peptidoglycan. This is enclosed by an outer membrane made of phospholipids other substances. The outer membrane prevents the initial stain from penetrating. The Escherichia coli has a gram negative cell walls dye (Levinson, 2014). B. Explain what causes gram-negative bacteria to stain pink. Gram-negative bacteria are bacteria that do not retain the crystal violet dye in the Gram stain procedure. The crystal violet dye is washed by acetone and counter stain stick on its cell wall. The cells appear pink because of the color of the counterstain (safranin) (Levinson, 2014). In this case, it applied to the Escherichia coli bacteria since the thinner peptidoglycan layer in their cell wall did not allow for the stain to retain. C. Explain what causes gram-positive bacteria to stain purple. The iodine binds the crystal violet stain in the cell wall preventing counter stain from sticking onto the wall. The lactobacillus and staphylococcus bacteria which...
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...In biology, in order to purify biological molecules, a common process called chromatography is often used. This process involves the separation of the large particles in the solution from the smaller particles. This is instrumental in filtering the solution, but without specialty scientific instruments, there is no way to immediately know the concentration of the, now separated, solution. However, there are multiple processes that are utilized to find unknown concentrations of a solution. One of these, known as the Bradford method, allows for an accurate, fairly simple, and timely assessment of these unknown concentrations by using a dye called the Coomassie Brilliant Blue G-250. The samples that contain this dye are run through a spectrophotometer, which reads the absorbance levels of the solution. Generally, the darker the solution is, the higher the concentration will be. This experiment utilizes both chromatography and the Bradford method to determine the concentrations of various protein samples. In this experiment, we worked with proteins over the course of two weeks in order to learn how to purify proteins in a solution by using chromatography and how to calculate the protein concentration in that solution. In the first week, protein samples were collected using chromatography, which is a process that is used to purify biological molecules. Two phases make up the chromatography process: the mobile phase, which consists of the solvent and molecules that are going to be...
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...Report The mixed unknowns were gram stained and looked under the microscope. There were gram-positive cocci and gram-negative bacilli. The unknowns were inoculated in blood agar and Mac-conkey. Three types of colonies were seen in the blood agar. All the three organisms showed different hemolysis, as there were alpha, beta and gamma hemolysis present. In the mac-conkey, there was colorless colony that denotes lactose non-fermenter. Each colonies were then inoculated into different blood agar to do further testing. Organism A I. Microscope- Gram positive cocci II. Blood Agar – Beta hemolysis Complete hemolysis. III. Catalase test– Positive Presence of bubbles when catalase was added to the slide with the organism in it as it can convert hydrogen peroxide into water and oxygen. 2H2O2---- 2H2O + O2 The organism falls in the genus Staphylococcus or Micrococcus. IV. Coagulase test, Staphylococcus Latex test – Positive Clumping of the latex reagent seen within 20 seconds. The organism makes coagulase. These tests suggest that the organism is Staphylococcus aureus. So for confirmatory test, the organism was inoculated in mannitol salt agar and incubated. The result was yellow color colony (mannitol fermenter), which means it is S. aureus. Organism B I. Microscope- Gram negative bacilli II. Blood agar- Gamma hemolysis No hemolysis. III. Mac. Conkey- Colorless colony The organism does not ferment lactose. IV. Oxidase test- Negative The organism falls under enterobacteriacea...
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