Potato dextrose agar media is primarily exercised for the growth and isolation of different yeasts and moulds. It can be practised in the form of a liquid broth and solid culture medium. PDA media serves as an ordinary growth medium for the yeasts and moulds, but it can be made selective by incorporating selective agents …
Bacterial growth factors primarily include temperature, pH, salt concentration, light source, nutritional and gaseous requirement etc. Microorganisms live in diverse natural habitats such as the atmosphere, hydrosphere and lithosphere. The environmental and nutritional factors may favour or restrict the growth of microorganisms. Some microbes survive in extreme conditions or the changing environment, while few can …
Bacterial flagella refer to the locomotory apparatuses, which help the bacteria to swim in the liquid nutrient medium. The bacteria possessing flagella are the motile organisms or flagellates. Conversely, the non-motile organisms or non-flagellates lack flagella. The width of bacterial flagella is much thinner and simpler than the eukaryotic flagella. The location, number and arrangement …
Synchronous culture is a technique of growing microorganisms at the same stage of their growth cycle under controlled conditions. Forced or mechanical selection methods induce synchrony in the microbial culture. Forced techniques induce synchrony in microorganisms by the shock treatment (temperature variation) or chemical treatment (nutritional difference). In contrast, the mechanical method uses filtration or …
B1 Vitamin or Thiamin is a kind of water-soluble vitamin that belongs to the vitamin B complex group. It was the first member of the vitamin B family isolated in 1926. Foods like poultry products, fortified cereals, nuts etc., are rich in thiamin content. Dietary supplements are also available to fulfil the demand for vitamin …
Vitamin B12 belongs to the Vitamin-B group. Structurally, vitamin B12 is the largest among all other vitamins (B1, B2, B3, B5, B6, B7 and B9) of the same group. Vitamin B12 is also known as Cobalamin, as it contains the mineral cobalt. Methylcobalamin and 5′ deoxyadenosylcobalamin are the two metabolically active forms of cobalamin. Bacteria …
Vitamin B6 is a water-soluble vitamin and a part of the vitamin B complex. It is named “Vitamin B6” because it comprises six vitamers, namely pyridoxine, alcohol, pyridoxal, an aldehyde and pyridoxamine (PLP and PMP). PLP (pyridoxal 5′-phosphate) and PMP (pyridoxamine 5′-phosphate) serve as the active coenzymes. Pyridoxine actively participates in protein, fat and carbohydrate …
The production of penicillin is practised commercially to treat various infections caused by gram-positive aerobic bacteria. Penicillin is a narrow-spectrum antibiotic or effective against many gram-positive bacteria, especially Streptococcus and Staphylococcus species. There are approximately 100 penicillins synthesized so far. For penicillin production, different strains of Penicillium (Penicillium notatum or Penicillium chrysogenum) are used. P. …
Flagella staining is a technique examining the presence and arrangement of bacterial flagella under the microscope. It is a specialized staining method, which requires a combination of special reagents to stain the bacterial flagella. The flagella appear as narrow appendages, which cannot be visualized by employing common stains. Therefore, the flagella staining uses mordants to …
Negative staining or Indirect staining refers to a staining technique that helps us visualize various microorganisms through light and electron microscopy. In bright field microscopy, the method of indirect staining employs liquid medium (black coloured dyes) like Nigrosin and India ink that stains the background, leaving the bacteria unstained. The negative staining technique uses a …