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Bacterial Lawn
Bacterial lawn is a term used by microbiologists to describe the appearance of bacterial colonies when all the individual colonies on a Petri dish agar plate merge to form a field or mat of bacteria. Bacterial lawns find use in screens for antibiotic resistance and bacteriophage titering. Bacterial lawns (often of ''Serratia marcescens'') are also used extensively when as an assay method when using bacteriophage as tracers in studies of groundwater flow. Although occasionally used as a synonym for biofilm, the term primarily applies to the simple, clonal, unstructured mats of organisms that typically only form on laboratory growth media. Biofilms—the aggregated form of microorganisms most commonly found in nature— are generally more complex and diverse and marked by larger quantities of extracellular structural matrix relative to the cellular biomass. Techniques Bacterial lawns can be produced manually by evenly spreading a high amount of bacteria onto an agar plat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Lawn 01
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationships wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomass (ecology)
The biomass is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to ''species biomass'', which is the mass of one or more species, or to ''community biomass'', which is the mass of all species in the community. It can include microorganisms, plants or animals. The mass can be expressed as the average mass per unit area, or as the total mass in the community. How biomass is measured depends on why it is being measured. Sometimes, the biomass is regarded as the natural mass of organisms ''in situ'', just as they are. For example, in a salmon fishery, the salmon biomass might be regarded as the total wet weight the salmon would have if they were taken out of the water. In other contexts, biomass can be measured in terms of the dried organic mass, so perhaps only 30% of the actual weight might count, the rest being water. For other purposes, only biological tissues count, and teeth, bones and shells are excluded. In some appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etest
Etest (previously known as the Epsilometer test) is a way of determining antimicrobial sensitivity by placing a strip impregnated with antimicrobials onto an agar plate. A strain of bacterium or fungus will not grow near a concentration of antibiotic or antifungal if it is sensitive. For some microbial and antimicrobial combinations, the results can be used to determine a minimum inhibitory concentration (MIC). Etest is a proprietary system manufactured by bioMérieux. It is a laboratory test used in healthcare settings to help guide physicians by indicating what concentration of antimicrobial could successfully be used to treat patients' infections. Use Etest is a quantitative technique for determining the antibiotic sensitivity and minimum inhibitory concentration (in µg/mL) of some bacteria including Gram-negative and Gram-positive aerobic bacteria such as Enterobacteriaceae, ''Pseudomonas'', ''Burkholderia'', '' Staphylococcus'', and ''Enterococcus'' species and fastidio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibiotic Sensitivity
Antibiotic sensitivity testing or antibiotic susceptibility testing is the measurement of the susceptibility of bacteria to antibiotics. It is used because bacteria may have resistance to some antibiotics. Sensitivity testing results can allow a clinician to change the choice of antibiotics from empiric therapy, which is when an antibiotic is selected based on clinical suspicion about the site of an infection and common causative bacteria, to directed therapy, in which the choice of antibiotic is based on knowledge of the organism and its sensitivities. Sensitivity testing usually occurs in a medical laboratory, and uses culture methods that expose bacteria to antibiotics, or genetic methods that test to see if bacteria have genes that confer resistance. Culture methods often involve measuring the diameter of areas without bacterial growth, called zones of inhibition, around paper discs containing antibiotics on agar culture dishes that have been evenly inoculated with bacteria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Culture
A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diagnostic methods used as a research tool in molecular biology. The term ''culture'' can also refer to the microorganisms being grown. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested, or both. It is one of the primary diagnostic methods of microbiology and used as a tool to determine the cause of infectious disease by letting the agent multiply in a predetermined medium. For example, a throat culture is taken by scraping the lining of tissue in the back of the throat and blotting the sample into a medium to be able to screen for harmful microorganisms, such as ''Streptococcus pyogenes'', the causative agent of strep throat. Furthermore, the term culture is more generally used informally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miles And Misra Method
The Miles and Misra Method (or surface viable count) is a technique used in Microbiology to determine the number of colony forming units in a bacterial suspension or homogenate. The technique was first described in 1938 by Miles, Misra and Irwin who at the time were working at the LSHTM. The Miles and Misra method has been shown to be precise. Materials * A calibrated dropping pipette, or automatic pipette, delivering drops of 20μl. * Petri dishes containing nutrient agar or other appropriate medium. * Phosphate Buffered Saline (PBS) or other appropriate diluent. * Bacterial suspension or homogenate. Method *The inoculum / suspension is serially diluted by adding 1x of suspension to 9x of diluent. When the quantity of bacteria is unknown, dilutions should be made to at least 10−8. *Three plates are needed for each dilution series, for statistical reasons an average of at least 3 counts are needed. *The surface of the plates need to be sufficiently dry to allow a 20μl drop to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibiotic Resistance
Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance. Fungi evolve antifungal resistance. Viruses evolve antiviral resistance. Protozoa evolve antiprotozoal resistance, and bacteria evolve antibiotic resistance. Those bacteria that are considered extensively drug resistant (XDR) or totally drug-resistant (TDR) are sometimes called "superbugs".A.-P. Magiorakos, A. Srinivasan, R. B. Carey, Y. Carmeli, M. E. Falagas, C. G. Giske, S. Harbarth, J. F. Hinndler ''et al''Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria... Clinical Microbiology and Infection, Vol 8, Iss. 3 first published 27 July 2011 ia Wiley Online Library Retrieved 28 August 2020 Although antimicrobial resistance is a naturally-occurring process, it is often the result of improper usage of the drugs and management of the infections. Antibiotic resistance is a major subset ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Plater
A spiral plater is an instrument used to dispense a liquid sample onto a Petri dish in a spiral pattern. Commonly used as part of a CFU count procedure for the purpose of determining the number of microbes in the sample.J. E. Gilchrist, J. E. Campbell, C. B. Donnelly, J. T. Peeler, and J. M. Delaney"Spiral Plate Method for Bacterial Determination" '' Appl Microbiol. '', 1973 February; 25(2): 244–252., In this setting, after spiral plating, the Petri dish is incubated for several hours after which the number of colony forming microbes (CFU) is determined. Spiral platers are also used for research, clinical diagnostics and as a method for covering a Petri dish with bacteria before placing antibiotic discs for AST. Mode of action The spiral plater rotates the dish while simultaneously dispensing the liquid and either linearly moving the dish or the dispensing tip. This creates the common spiral pattern. If all movements are done in constant speed, the spiral created would hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drigalski Spatula
A Drigalski spatula is a type of cell spreader consisting of a cylindrical rod or wire, usually of metal or glass, bent in the shape of a triangle with a handle.Franz-Josef Bibo, Hanno Birke, Helmut Böhm, Walter Czysz, Heinz Gorbauch, Hans J. Hoffmann, Hans-Herrmann Rump, and Wilhelm Schneider (2011): ''Water Analysis: A Practical Guide to Physico-Chemical, Chemical and Microbiological Water Examination and Quality Assurance'', page 633. Ronald Westphal (1988): Microbiological Techniques in School', page 34. Document No. 28 in the series ''Science and Technology Education''.Reiner Hedderich, Rolf Müller, Yasmin Greulich, Norbert Bannert, Gudrun Holland, Petra Kaiser, Rolf Reissbrodt (2011: "Mechanical damage to Gram-negative bacteria by surface plating with the Drigalski-spatula technique". ''International Journal of Food Microbiology'', volume 146, issue 1, pages 105-107. (2019):Item 41049: Drigalski spatulas made of glass. Assistent (Karl Hecht) online catalog. Accessed on 2019- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cotton Swab
Cotton is a soft, fluffy Staple (textiles), staple fiber that grows in a wikt:boll, boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor percentages of waxes, fats, pectins, and water. Under natural conditions, the cotton bolls will increase the dispersal of the seeds. The plant is a shrub native to tropical and subtropical regions around the world, including the Americas, Africa, Egypt and India. The greatest diversity of wild cotton species is found in Mexico, followed by Australia and Africa. Cotton was independently domesticated in the Old and New Worlds. The fiber is most often Spinning (textiles), spun into yarn or thread and used to make a soft, breathable, and durable textile. The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric dated to the fifth millennium BC have been found in the Indus Valley civ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature
Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are part of nature, human activity is often understood as a separate category from other natural phenomena. The word ''nature'' is borrowed from the Old French ''nature'' and is derived from the Latin word ''natura'', or "essential qualities, innate disposition", and in ancient times, literally meant "birth". In ancient philosophy, ''natura'' is mostly used as the Latin translation of the Greek word ''physis'' (φύσις), which originally related to the intrinsic characteristics of plants, animals, and other features of the world to develop of their own accord. The concept of nature as a whole, the physical universe, is one of several expansions of the original notion; it began with certain core applications of the word ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiologist
A microbiologist (from Ancient Greek, Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of Microorganism, microscopic organisms such as bacteria, algae, fungi, and some types of parasites and their vectors. Most microbiologists work in offices and/or research facilities, both in private biotechnology companies and in academia. Most microbiologists specialize in a given topic within microbiology such as bacteriology, parasitology, virology, or immunology. Duties Microbiologists generally work in some way to increase scientific knowledge or to utilise that knowledge in a way that improves outcomes in medicine or some industry. For many microbiologists, this work includes planning and conducting experimental research projects in some kind of laboratory setting. Others may have a more administrative role, supervising scientists and evaluating their results. Microbiologists working in the medi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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