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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 or 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 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Lawn 01
Bacteria (; : 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 the air, soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and 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 mutualistic, commensal and parasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomass (ecology)
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 application ... [...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 MIC of microorganisms. It is used for a range of Gram-negative and Gram-positive bacteria such as ''Pseudomonas'', ''Staphylococcus'', and ''Enterococcus'' species, as well as fastidious bacteria, such as ''Neisseria'' and ''Streptococcus pneumoniae''. It can also be used t ... [...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 bacter ... [...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 research tools 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 or AR) occurs when microbes evolve mechanisms that protect them from antimicrobials, which are drugs used to treat infections. This resistance affects all classes of microbes, including bacteria (antibiotic resistance), viruses (antiviral resistance), parasites (antiparasitic resistance), and fungi (antifungal resistance). Together, these adaptations fall under the AMR umbrella, posing significant challenges to healthcare worldwide. Misuse and improper management of antimicrobials are primary drivers of this resistance, though it can also occur naturally through genetic mutations and the spread of resistant genes. Antibiotic resistance, a significant AMR subset, enables bacteria to survive antibiotic treatment, complicating infection management and treatment options. Resistance arises through spontaneous mutation, horizontal gene transfer, and increased selective pressure from antibiotic overuse, both in medicine and agriculture, which accelerat ... [...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 Colony-forming unit, 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 Antibiotic sensitivity, AST. Mode of action The spiral plater rotates the dish while simultaneously dispensing the liquid and either linear motion, linearly moving the dish or the dispensing tip. This creates the common spiral pattern. If all movements ... [...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 201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cotton Swab
Cotton swabs (American English) or cotton buds (British English), also Q-tips ( proprietary eponym), are wads of cotton wrapped around a short rod made of wood, rolled paper, or plastic. They are most commonly used for ear cleaning, although this is not recommended by physicians. Other uses for cotton swabs include first aid, cosmetics application, cleaning, infant care, and crafts. Some countries have banned the plastic-stemmed versions in favor of biodegradable alternatives over concerns about marine pollution. History The first mass-produced cotton swab was developed in 1923 by Polish-American Jew Leo Gerstenzang after he watched his wife attach wads of cotton to toothpicks to clean their infant's ears. His product was originally named "Baby Gays" in recognition of their being intended for infants before being renamed "Q-tips Baby Gays", with the "Q" standing for "quality". The product eventually became known as "Q-tips", which went on to become the most widely sold b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature
Nature is an inherent character or constitution, particularly of the Ecosphere (planetary), ecosphere or the universe as a whole. In this general sense nature refers to the Scientific law, laws, elements and phenomenon, phenomena of the physical world, including life. Although humans are part of nature, human activity or humans as a whole are often described as at times at odds, or outright Anthropocentrism, separate and even superior to nature. During the advent of modern scientific method in the last several centuries, nature became the passive reality, organized and moved by divine laws. With the Industrial Revolution, nature increasingly became seen as the part of reality deprived from intentional intervention: it was hence considered as sacred by some traditions (Jean-Jacques Rousseau, Rousseau, American transcendentalism) or a mere decorum for divine providence or human history (Hegel, Marx). However, a vitalist vision of nature, closer to the pre-Socratic one, got reborn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiologist
A microbiologist (from Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of 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 medical field, such as clini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
