Objective lens is the most important lens of an optical microscope, which is kept closest to the specimen. It is the first lens that collects the light coming from the specimen (emitted or reflected). It bends the light rays and forms a real, magnified image at an intermediate image plane. This primary image is then … Read more
Microscope condenser is an optical lens system placed below the stage of the microscope between the light source and the specimen. It is used to collect the divergent light rays and concentrate them as a cone of light on the specimen. It helps in giving uniform illumination so that the light can pass through the … Read more
Ion Exchange Chromatography (IEC) is a chromatographic separation technique used to separate and purify molecules based on their net surface charge. It works mainly for charged biomolecules like proteins, peptides, amino acids and nucleic acids. In this method, separation depends on electrostatic attraction between the sample and the charged stationary phase. Ion exchange chromatography is … Read more
Ever wondered about the little scientific marvels you hold in your hand during chemistry or biology labs? We’re shining a spotlight on one such unsung hero of the scientific world – disposable glass pasteur pipettes. These handy tools, so often taken for granted, have a fascinating history and a crucial role in your experimental success. Let’s dive in and … Read more
Glass dropper pipette is a small glass device used to transfer liquid in drop by drop form. It is also called as eye dropper or Pasteur pipette. It is mainly used when a small quantity of liquid is to be taken and dispensed in controlled drops. It is generally made of three parts. A rubber … Read more
ONPG test is a rapid biochemical test used in microbiology to detect the presence of β-galactosidase enzyme in bacteria. It is used to identify organisms which can produce β-galactosidase but may not ferment lactose in routine lactose tests. Normally lactose fermentation needs two enzymes. One is lactose permease which transports lactose inside the cell. Another … Read more
The ability to develop in the presence of varying concentrations of sodium chloride (NaCl) has been used to distinguish between various bacteria.
Sulfur Reduction Test (H2S production test) is a biochemical test used to see the ability of bacteria to reduce sulfur containing compounds and liberate hydrogen sulfide gas (H2S). It is used mainly for differentiation of Gram negative enteric bacilli. It helps to separate H2S producers like Salmonella and Proteus from non producers like Shigella and … Read more
Growth at 42°C Test is a physiological laboratory test used to identify and differentiate bacteria based on their ability to grow at 42°C temperature. It is done because 42°C is higher than the normal incubation temperature (35–37°C) and many bacteria cannot tolerate this heat. Bacteria that can grow at this temperature are considered to have … Read more
The MRS formulation was made by de Man, Rogosa, and Sharpe to replace a variable product (tomato juice) and give lactobacilli in general a good place to grow.
