...Colloids and Surfaces B: Biointerfaces 102 (2013) 412–419 Contents lists available at SciVerse ScienceDirect Colloids and Surfaces B: Biointerfaces journal homepage: www.elsevier.com/locate/colsurfb Non-cytotoxic antibacterial silver–coumarin complex doped sol–gel coatings Swarna Jaiswal a,b , Kunal Bhattacharya c , Maeve Sullivan d , Maureen Walsh d , Bernadette S. Creaven d , Fathima Laffir e , Brendan Duffy a,∗ , Patrick McHale b a Centre for Research in Engineering Surface Technology (CREST), FOCAS Institute, Dublin Institute of Technology, Dublin 8, Ireland School of Biological Sciences, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland c Nanolab Research Centre, FOCAS Institute, Dublin Institute of Technology, Dublin 8, Ireland d Centre for Pharmaceutical R&D, School of Science, Institute of Technology, Tallaght, Dublin 24, Ireland e Materials & Surface Science Institute, University of Limerick, Dublin, Ireland b a r t i c l e i n f o a b s t r a c t Microbial colonisation on clinical and industrial surfaces is currently of global concern and silane based sol–gel coatings are being proposed as potential solutions. Sol–gels are chemically inert, stable and homogeneous and can be designed to act as a reservoir for releasing antimicrobial agents over extended time periods. In the present study, silver nitrate (AgN) and a series of silver coumarin complexes based on coumarin-3-carboxylatosilver (AgC) and it is 6, 7 and 8 hydroxylated analogues...
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...place. In order to be able to observe the colony morphology of both Archaea, they were grown on an agar surface that allowed them to form colonies of characteristic colour and appearance. In order to observe the physiology of both Archaea on the effect of salt concentration, pH, and temperature, they needed to be placed on agar plates and incubated for two weeks. Being incubated for two weeks, allowed the halophilic archaeal cultures to grow. The objective of this experiment was to determine the morphological and biochemical characteristics along with the growth requirements of the halophilic Archaeans; Halobacterium salinarum NRC-1 and Haloferax volcanii DS2. Introduction The domain, Archaea, possesses prokaryotic cells and has a cell wall that contains no peptidoglycan. Archaea contain rRNA that is unique to the Archaea as indicated by the presence of molecular regions. Archaea usually live in extreme environments and include methanogens, extreme halophiles, and hyperthermophiles. One reason for this is that the ether-containing linkages in the Archaea membranes are more stable and are able to withstand higher temperatures and stronger acid concentrations. The other two domains of life are Bacteria and Eukarya. Unlike the Bacteria and the Eukarya domains, the Archaea domain has membranes composed of branched hydrocarbon chains that are attached to glycerol by ether...
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...analyzed it under a microscope. We were then able to assess what kind of bacteria we had and if it was gram positive or negative. Introduction: Simple staining (the use of a single stain) allows a microbiologist to observe the morphology (shape) and arrangement of bacteria. In order to classify bacteria into different groups a differential staining procedure must be done. A differential stain involves the use of two or more stains. Depending on the components of the bacterial cell wall or outer layers, the bacteria will either retain the primary stain or have the primary stain removed in a decolorizing step and then retain the secondary stain. The gram stain is the most common differential stain used in the microbiology laboratory to categorize bacteria. The primary stain is the cationic dye Crystal violet and the secondary stain is the cationic dye Safranin. Since both stains are cationic, they are both attracted to the negatively charged particles in the bacterial cell wall. So what causes some bacteria to retain the Crystal violet stain while others are decolorized by the alcohol and then pick up the Safranin stain? The current theory behind gram staining is that the crystal violet enters the...
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...resistance of tetracyclines led to a series of studies on the development of semisynthetic tetracyclines to circumvent the resistant organisms. In order to better design the structures of tetracycline derivatives, research on the action mode of tetracyclines, mechanisms of resistance, biosynthesis and total synthesis of tetracyclines were also performed. Keywords: Tetracyclines, Structure-activity Relationship, Mode of Action, Mechanisms of Resistance, Biosynthesis, Total Synthesis 1. Introduction Tetracyclines are a group of polyketide broad-spectrum antibiotics that has activity against a variety of gram-positive and gram-negative bacteria, mycoplasmas, chlamydiae and peotozoan parasites [1]. The discovery of tetracycline was in the 1940s. At that time, the problems related to the production of Pennicillin has been solved and pharmaceutical industry and academic institutes started to concentrate their energy on the development of new antibiotics. In 1948, the first member of tetracycline family—chlorotetracyclin, or Aureomycin was discovered as an isolate of Streptomyces Aureofaciens in an antibiotic screening program functioned in Lederle Labs [2]. In 1950, oxytetracycline or Terramycin—second member of tetracycline was found as a metabolite of Streptomyces rimosus by Finlay et al. [3] and the chemical structure of oxytetracycline was defined by Woodward, which was a hallmark in tetracycline research. Since then, tetracyclines has been intensively used in both human therapy...
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...Difference between a cell wall And a Gram Stain Janet Myers 12:30p.m. Tuesday February 23 2016 Introduction: Gram staining is based on the ability of bacteria cell wall to retaining the crystal violet dye during solvent treatment. The cell walls for Gram-positive microorganisms have a higher peptidoglycan and lower lipid content than gram-negative bacteria. Bacteria cell walls are stained by the crystal violet. Iodine is subsequently added as a mordant to form the crystal violet-iodine complex so that the dye cannot be removed easily. This step is commonly referred to as fixing the dye. However, subsequent treatment with a decolorizer, which is a mixed solvent of ethanol and acetone, dissolves the lipid layer from the gram-negative cells. The removal of the lipid...
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...Chromatography INTRODUCTION IN THIS LAB, WE WILL BE EXPRESSING THE GREEN FLUORESCENT PROTEIN (GFP) IN BACTERIA AND PURIFYING IT USING COLUMN CHROMATOGRAPHY. THE SPECIFIC TYPE OF CHROMATOGRAPHY WE WILL BE USING IS HYDROPHOBIC INTERACTION CHROMATOGRAPHY (HIC). THE FOLLOWING IS INFORMATION FROM BIO-RAD INC., THE SUPPLIER OF THE REAGENTS: GFP has several stretches of hydrophobic amino acids, which results in the total protein being very hydrophobic. When the supernatant, rich in GFP, is passed over a HIC column in a highly salty buffer (Binding Buffer), the hydrophobic regions of the GFP stick to the HIC beads. Other proteins which are less hydrophobic (or more hydrophilic) pass right through the column. This single procedure allows the purification of GFP from a complex mixture of bacterial proteins. Loading the GFP supernatant onto the chromatography column When students load the GFP supernatant onto their columns, it is very important that they do not disturb the upper surface of the column bed when performing the chromatography procedure. The column matrix should have a relatively flat upper surface. A slightly uneven column bed will not drastically affect the procedure. However, subsequent steps of loading, washing, and eluting should minimize disrupting the column such that beads "fluff up" into the buffer. When loading the GFP supernatant onto the column, the pipette tip should be inserted into the column and should rest against the side of the column...
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...Cellular Structures and Pathogenicity All the various surface components of a bacterial cell are important in the ecology because they mediate the contact of the bacterium possesses result from immediate contact with its environment. Its must use its surface components to assess the environment and respond in a way that supports its own existence and survival in that environment. The surface properties of a membrane and cell envelope, including capsules, glycocalyx, slayers, peptidoglycan and lps, and the other surface structures, such as flagella and pili or fimbriae. Bacterial surface components may have a primary biological function that has nothing to do with path ogenicity. However, there are endless examples wherein a bacterial surface component plays an indispensable role in the pathogenesis of infectious disease. Bacterial structures may act as permeability barriers that allow selective passage of nutrients and exclusion of harmful substances; adhesions used to attach or adhere to specific surfaces or tissues; enzymes to mediate specific reactions on the cell surface important in the survival of the organism; protective structures against phagocytic engulfment or killing; antigenic disguises to bypass activation oh host immune defenses; endotoxins, generally cell wall components, that cause an inflammatory response in the host; “sensing proteins” that can respond to temperature, osmolality, salinity, light, oxygen, genome of the cell that will cause expression of some...
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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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...To discover my unknown, I first conducted the gram test on my species. The result was gram positive coccus. After that I did the catalase test which determines if the bacteria can breakdown hydrogen peroxide into oxygen and water. My unknown was catalase positive which lead to three genera, one of which my unknown could be. The three genera were Micrococcus, Planococcus, Staphylococcus. By doing the SIM motility test I learned that my unknown was nonmotile. With the FTM tube test I learned that my unknown was a facultative anaerobe. The sugar fermentation tubes resulted in my species fermenting acid but were negative for gas. These tests helped me decide that my unknown’s genius was Staphylococcus. Using the white key, I got the best fit match for Staphylococcus epidermidis. Of the three Staphylococcus options in the white key, Staphylococcus aureus had a gold pigment which my unknown was negative for. Staphylococcus saprophyticus was negative for nitrate reduction, and an acid former for mannitol unlike my unknown. Therefore, Staphylococcus epidermidis had the most matches on the white key. There were no tests which I had to redo due to inconclusiveness. For the litmus milk reaction, my organism was acid, alkaline and reduction negative, coagulation and peptonization positive. On the white key my unknown did not match any of the option listed for the genus Staphylococcus. Compared to Bergey’s Manuel of Systematic Bacteriology, my organism matched the many descriptions listed...
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...“Choose 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 explain that it is gram-negative. Another test we did on the bacteria was a streak plate method, which would show how many colonies...
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...Two overnight cultures of unknown bacteria were provided in dilution tubes, labeled 18X and 18Y. The provided cultures were used for Gram staining. A heat fixed smear of each unknown was prepared on two separate clean glass slides. The smears were flooded with crystal violet (1 minute), rinsed with water (2 seconds), covered with Gram’s iodine (1 minute), rinsed with water (2 seconds), decolorized by 95% alcohol applied in a drop wise fashion, rinsed with water (2 sec), counterstained with safranin (30 seconds), and rinsed with water a final time (2 seconds). The stains were dabbed dry then examined under a microscope at 100x with oil immersion for cell shape, cell size, and whether the cells stained Gram-positive (purple) or Gram-negative (pink)....
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...yellow in color, with sediment gathered at the bottom. It has a strong odor, and I question whether I have smelled it before. The first test I’m doing is a Gram stain. Doing 3 slides – all air dried and heat fixed. Also streaking 2 plates today: TSA plate, and 2nd plate will be based on the results of the Gram stain. Either: MSA= isolates S. aureus, inhibits G-, EMB= fecal coliforms, G- growth (selective isolation G- rods), MAC= promotes G- growth. I am worried that I won’t be able to achieve isolation of separate colonies from the broth culture when I streak the plates. Viewed results of Gram stain with microscope under 100x oil immersion. Results of 1st Gram stain were inconclusive, so staining again with another slide. Many more cells on this slide. 2nd Gram stain = G- bacilli (rods), confirmed with Claudia. Decide to streak 2nd plate = MAC since I believe I have a G- bacteria. Day 2 – Achieved isolation on both TSA and MAC agar’s. Definite growth on MAC means I do have a G- bacteria. Will now perform a 2nd Gram stain from TSA plate to confirm Gram status; confirmed that it is G- . After looking at the chart, decided to try to narrow down options by doing an oxidase test. There are 6 oxidase positive bacteria, and 8 oxidase negative bacteria. Oxidase test results = negative. Inoculated a TSA slant today before leaving. Day 3 – After looking at chart and narrowing down options, decided next test should be a bile esculin hydrolysis test. I don’t want to waste...
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...this book do not intend disrespect for any particular patient population or racial or ethnic group but are solely presented as memory devices to assist in the learning of a complex and important medical subject. We welcome suggestions for future editions. 1) Write in a conversational style for rapid assimilation. 2) Include numerous figures serving as "visual memory tools" and summary charts at the end of each chapter. These can be used for "cram sessions" after the concepts have been studied in the text. 3) Concentrate more on clinical and infectious disease issues that are both interesting and vital to the actual practice of medicine. MARK GLADWIN, MD BILL TRATTLER, MD D CONTENTS Preface v PART 1 1 2 3 BACTERIAL TAXONOMY CELL STRUCTURES, VIRULENCE FACTORS, and TOXINS...
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...This approach is used to distinguish between a gram negative and gram positive bacteria. The staining is based on the contents of the cell wall. During the procedure stains/dyes are being used as well as a mordant and a decolorizer. Because gram positive has a thick cell wall the stains are being retained leaving the cells purple after being decolorized. As for gram negative bacteria, the cell wall is thin and holes are created during the decolorizing step, causing the stain to wash out leaving the cells...
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...Cellular Structures and Pathogenicity Brittany McMahon ITT Technical College Cellular structures have different impacts on the ability for bacteria to cause disease. Mainly the cells external structures have the biggest effect to adhere to the cells to cause disease. One structure being the pili, a rigid, thin fiber made of protein that expands from the cell surface. The main function are to adhere specific bacterial cells to specific surfaces. There are typically only one or two pili per cell (Hartsock, Angela 2016). Pili that is coated with adhesins can determine the mucosal surface of the respiratory tract and will only adhere to that specific surface to infect those cells (Hartsock, Angela 2016). This bacteria is known as Bordetella. The fimbria is another external structure that is similar to the pili. They are short, filamentous structures that are in large numbers that help in attachment to surfaces (Hartsock, Angela 2016). Like pili the fimbria target tissues they believe will be the best host. Flagella has a completely different function from the pili and fimbria. The main function for flagellum is motility. They are long, tail like appendages attached to bacterial cells that allow the movement (Schuhmacher, J., Rossmann, F., Dempwolff, F., Knauer, C., Altegoer, F., Steinchen, W., Bange, G. 2015). Flagella is made of protein called flagellin. The proteins form a long chain that look like a helical shape. From the cell membrane the flagellum is wide and attaches...
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