Gel Filtration Chromatography separates the samples based on the molecular size and shape of specimen present in them.
Phase contrast microscope is a modified version of bright field microscope that helps in visualizing cells or objects without staining.
The chromatography using thin layers of adsorbent held on a glass plate is known as thin layer chromatography. It has stationary and the mobile phase.
Chromatography is a separation technique that uses a stationary and mobile phase to separate the mixture.
There are two types of microscope: light microscope and electron microscope. Light microscope uses visible light and electron microscope uses beam of electrons as a source of illumination.
A number of commercial providers are marketing various probiotic products. With so many options choosing a probiotic can be confusing.
Light projects through an opening in the stage. Then the projected light hits the object and enters the objective lens. Resolution is the ability of a lens to distinguish two adjacent points as distinct and separate.
Microscope is a piece of laboratory optical equipment that is used to magnify small things that are too small for the details to be seen by the naked eye.
Jargon refers to technical vocabulary that is specific to a particular profession or field.
Species of Lactobacillus and Bifidobacterium are most commonly used as probiotics. Other are Saccharomyces boulardii, Streptococcus, etc.
Prebiotics are complex carbohydrates that escape digestion in the upper gastrointestinal tract and are available for microorganisms living in the colon.
Although most prokaryotes cannot survive in nature without their cell walls, some do so naturally. For example, mycoplasma and thermoplasma.
Organisms that can utilize radiant energy (sunlight) are called phototrophs. Chemotrophs are organisms that can harvest energy from chemicals.
Archaea is a group of phylogenetically related prokaryotes distinct from Bacteria and known for tolerance to physiochemical extremes.
Human skin is home to billions of diverse bacteria, archaea, fungi, and viruses with bacteria making up the vast majority
Quorum sensing (QS) is a bacterial cell-cell signaling mechanism that helps them to adjust gene expressions based on requirements.
Electron microscope is a type of microscope with high resolving power, that uses electrons instead of visible light to illuminate the object.
Fluorescence microscopy is widely used in diagnostic microbiology (diagnosis of tuberculosis, trichomoniasis) and in microbial ecology.
Sterilization and decontamination in the medical supplies (surgical supplies, vaccines, and drugs) is done using radiation sterilization.
Disinfection is a process whereby pathogenic organisms, but not necessarily all microorganisms or spores, are destroyed.
Most microorganisms grow best around neutral pH values (6.5 - 7.0), but some thrive in extreme pH conditions (pH10).
Gram-positive bacilli are a diverse group of bacteria responsible for variety of infections such as gas-gangrene, tetanus, anthrax, etc.
Psychrophiles can grow at 0°C, mesophiles have optimum temperature near 37°C, and thermophiles grow best at 50-60°C.
Reagents are primary stain (crystal violet), mordant (iodine), decolorizer (ethanol or acid-alcohol), and counterstain (safranin or dilute carbol-fuchsin).
Detection of the parasites or their particular stages (ova/egg, cyst, larva or trophozoite) in the stool specimen is diagnostic.
SEM provides detailed images of the surfaces of cells whereas TEM provides details about internal composition, morphology, crystallization.
Bacterial culture method for estimating the viable bacterial count after serial dilutions (when required).
The most probable number (MPN) is a statistical serial dilution method for estimating viable numbers of bacteria present in a food or water sample.
It tests for the presence of acid and/or gas produced from carbohydrate fermentation. and is useful in differentiating among bacterial groups or species.
Odor of colonies of bacteria may help in their identification but sniffing culture plates is not a good idea and you may contract a disease.
One of the best methods to determine the number of bacteria present per mL of liquid broth/specimen.
The best way to visualize capsule is to stain the background using an acidic stain and to stain the cell itself using a basic stain.
Routine method for the isolation of bacteria from clinical specimen or for obtaining individual isolated colonies from a mixed culture.
Any basic dye such as methylene blue, safranin, or crystal violet can be used to color the bacterial cells. Not performed routinely in a diagnostic lab.
Taeniasis is caused by both Taenia solium and Taenia saginata but only infections with Taenia solium may cause cysticercosis. Find out why
Micrococcus is lysostaphin and furazolidone resistant, bacitracin sensitive and microdase positive. Find the results of Staphylococcus.
Eukaryotic cells contain a nucleus with a nuclear membrane enclosing multiple chromosomes, while prokaryotic cells have a single chromosome.
Buffy coat suspension is a concentrated leukocyte suspension which contains WBCs and platelets.
In Schaeffer-Fulton`s method, primary stain-malachite green is forced into the spore by steaming the smear, safranin is counterstain.
Safety in a microbiology laboratory is important in the prevention of infection because virulent and/or potentially pathogenic microorganisms are cultured (grown) there.
Robert Koch is also known as the 'Father of Clinical Microbiology.' Koch's postulate provided guidelines to identify the causative agent of an infectious disease.
Catalase test is used to distinguish among Gram-positive cocci. Staphylococci are catalase-positive but Streptococci are catalase-negative.
Enterobacteriaceae is a family of gram-negative rods which are catalase positive and oxidase negative.
Medical microbiologists working in reference laboratories might be devoted to carrying out research in a particular gene whereas the microbiologist working in a general diagnostic laboratory are confined to routine laboratory works.
Modified Kirby-Bauer disc diffusion test method is a reference method to test the susceptibility of a bacterial isolate in a clinical laboratory.
Gram positive bacteria appear purple and gram-negative bacteria appear pink when stained by Gram-staining methods.
Based on the types and number of dyes used, staining can be categorized simple stain, negative stain, impregnation methods and differential stain.
There are four risk groups (RG1-RG4, RG1 being lowest risk) and four bio-safety levels (BSL-1 to BSL-4). BSL-4 is maximum containment.
Most common cause are E. coli, S. aureus, Salmonella, Klebsiella pneumoniae, S. pnuemoniae and H. influenzae.
Common cold, also known simply as a cold, is a self-limiting viral infection of the upper respiratory tract.
Nobel prize in Physiology and Medicine-2020 was given to three different virologist for the discovery of Hepatitis C virus.
Obligate intracellular bacteria cannot be grown in artificial media (agar plates/broths) in laboratories but requires viable eukaryotic host cells.
Typical growth curve of microorganisms in a closed system consists of distinct phases called lag phase, log phase, stationary phase, and death phase.
BSL2 is suitable for organisms that pose a moderate individual risk and low community risk for infection.
Microorganisms can be classified as obligate aerobes, facultative, microaerophilic, aerotolerant and obligate anaerobes based on their oxygen requirements.
Bacteria exist in four basic morphologies: cocci; rod-shaped cells, or bacilli; spiral-shaped cells, or spirilla; and comma-shaped cells, or vibrios.
Motility patterns of Gram-negative bacteria are also used for their identification. Most of the Gram-positive bacteria are non-motile.
Peptidoglycan consists of carbohydrate backbone composed of alternating units of NAG and NAM molecules attached through β-1,4-glycosidic bonds.
Concentrated deposits of certain substances which are presented/located in the cytoplasm of certain bacteria.
Teichoic acids are fibers of glycerol phosphate or ribitol phosphate and is located in the cell-wall of gram-positive bacteria.
Lipopolysaccharide (LPS) layer also called the outer membrane is the outermost layer present in the cell wall of gram-negative bacteria.
Pili or fimbriae are hair-like filaments that help pathogen in adherence to host cells. Sex pili play role in conjugation.
Flagella are long, whiplike appendages that move the bacteria toward nutrients and other attractants
Bacterial spores are highly resistant, dormant structures formed in response to adverse environmental conditions
Capsule is a gelatinous layer covering the bacterium and is a major virulence factor of S. pneumoniae, H. influenzae, etc.
Coagulase test detects clumping factors and bound coagulase and differentiates Staphylococcus aureus (positive) from CoNS (negative).
