...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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...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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...BMC Complementary and Alternative Medicine This Provisional PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon. Polar extracts from (Tunisian) Acacia salicina 'Lindl. Study of the antimicrobial and antigenotoxic activities BMC Complementary and Alternative Medicine 2012, 12:37 doi:10.1186/1472-6882-12-37 Jihed Boubaker (jihed.boubaker@yahoo.fr) Hedi Ben Mansour (hedi.mansour@hotmail.fr) Kamel Ghedira (kamel.ghedira@gmail.com) Leila Chekir-Ghedira (leila.chekir@laposte.net) ISSN Article type Submission date Acceptance date Publication date Article URL 1472-6882 Research article 3 September 2011 10 April 2012 10 April 2012 http://www.biomedcentral.com/1472-6882/12/37 Like all articles in BMC journals, this peer-reviewed article was published immediately upon acceptance. It can be downloaded, printed and distributed freely for any purposes (see copyright notice below). Articles in BMC journals are listed in PubMed and archived at PubMed Central. For information about publishing your research in BMC journals or any BioMed Central journal, go to http://www.biomedcentral.com/info/authors/ © 2012 Boubaker et al. ; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the...
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...Materials and methods Location of the experiments This study was performed at the Plant Pathology Department, Faculty of Agriculture, Cairo University, Giza, Egypt Isolation of the pathogens Lettuce plant (cv. Aviram) showing wilt symptoms were collected from different fields located at Giza, Qalubiya, and Behira governorates. The infected roots were washed several times with tap water, cut tissues with the discolored vascular system or cortex after removing and discarding the epidermis into small pieces (Hubbard & Gerik 1993), surface sterilized by immersing in 2% sodium hypochlorite for 2 min, washed in several changes of sterile water and finally aseptically transferred onto potato dextrose agar medium (PDA) in Petri plates and incubated at 28±1ºC for 7 days. The growing fungi were purified and identified according to their morphological and molecular characteristics. Pathogenicity tests Inoculum preparation F. oxysporum f. sp. lactucae isolates Fo-1, Fo-2, and Fo-3 which yielded from Giza, Qalubiya, and Behera governorates, respectively were separately grown onto 250 ml flasks containing 100 ml autoclaved potato dextrose broth medium. The flasks were inoculated with one disk (4 mm diameter) taken from the margins of fresh cultures grown on PDA medium then incubated at 28±1ºC for 14 days. The suspension was filtered through two layers of cloth sheet. The concentration of the spores was determined by hemocytometer and diluted with sterile distilled water to obtain a final...
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...colony morphology. Figure 1 shows the following results for unknown H28 colony morphology: irregular colonies, cream color, undulate margin, and flat elevation on a TSA plate. Furthermore, TSA slant streak patterns was perform to identify arborescent growth and tryptic soy broth procedure was perform to identify sediment for growth of unknown H28. The second procedure that was done was a gram stain to determine the gram reaction and Fig. 1. TSA plate shows irregular colonies, cream color, undulate margin, and flat elevation of unknown H28. 1 identify the morphology. The morphology of unknown H28 is bacilli and the arrangement is streptobacilli. After determining that unknown H28 is a gram positive rod, specific biochemical test were performed. The phenol red broth tests for sucrose and lactose fermentation. Figure 2 shows the following results for phenol red broth test of unknown H28: glucose (Acid), maltose (Acid), and sucrose (Acid). Glucose, maltose, and sucrose did have the enzyme to go through fermentation. The next procedure is the citrate test on a citrate slant. The results was negative Fig. 2. Phenol red broth showing: glucose...
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...distinguishes between gram-positive and gram-negative bacteria. Bacteria that stain purple are considered gram-positive and bacteria that stain pink are considered gram-negative. B. What is the difference between gram-positive and gram-negative cell walls? Gram-positive cell walls are thick and have many interconnecting layers of peptidoglycan. Gram-negative cell walls are thin and have only one layer of peptidoglycans that are two or three layers thick. C. What is the purpose of crystal violet in the Gram’s stain procedure? The crystal violet increases the contrast of both gram-negative and gram-positive bacteria making them look purple. D. What is the purpose of iodine in the Gram’s stain procedure? (What is a mordant?) The purpose of iodine in Gram’s stain procedure is it helps set the stain by forming an insoluble crystal violet-iodine complex. It helps keep the crystal violet to the cell. E. What is the purpose of acetone-alcohol in the Gram’s stain procedure? The purpose of acetone-alcohol is it is a decolorizer that distinguishes between gram-negative and gram-positive. Only the gram-positive bacteria will keep the crystal violet-iodine complex. Gram-negative bacteria will not keep the color and the decolorizer will wash off the stain. F. What is the purpose of safranin in the Gram’s stain procedure? The safranin in the Gram’s stain is a basic dye that directly stains the gram-negative bacteria that have become decolorized. The gram-positive bacteria are already stained...
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...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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