FineMind Labs

Isolation of aquatic fungi by Baiting Technique

In a water sub system, the aquatic fungi grow on litter of plants and animals, decompose them and render into simpler forms. These fungi can be isolated by baiting technique. Different type of baits such as hemp seeds, mustered seeds, vegetable chips, plant leaves etc. Are used for isolation of aquatic fungi. 

Requirements for isolation of aquatic fungi 

Baits (hemp seeds) 

Sampling bottles (of…

Isolation of Azobacter from garden soil

Azobacter spp. Is one of the most important microorganism found in soil. They live in free state and help to fix nitrogen of atmosphere into ammonia. The presence of Azobacter in the soil can be identified by its isolation from soil. Azobacter is a Gram negative, motile, rod shape, pleomorphic aerobic bacterium which produce catalase. It hydrolyses starch and produce water soluble pigment…

Staining of free living Protozoa (non-pathogen)

The free living protozoa are generally found in stagnant pond water and soil. There are more than 20,000 known species of free living Protozoa. Unlike parasitic group free loving Protozoa take nutrition by engulfing bacteria, yeast and algae. Common examples of free living Protozoa are Amoeba proteus, Euglena, Paramicium etc. 

Requirements for staining  of free living Protozoa  

Stagnant pound…

Isolation of protozoa from the soil

Protozoa are the eukaryotic, unicellular non-photosynthetic microorganisms devoid of cell wall. They fall into the division Protista. Total number of species of protozoa account for about 4,000, of which some of them are human pathogens and the others non-pathogens. The non-pathogenic species are free-living in soil and involved in establishment of relationships with the other microorganisms.…

Sampling of Bacteria and Fungi from Air

Air can be sampled for the presence of bacteria by their collection on culture medium using open Petri dishes containing a suitable medium. Now-a-days more accurate sampling can be done by use of a slit-sampler device that impinges air on agar surface. The apparatus consists of a mechanical pump, a chamber in which Petri dish of a nutrient agar is mechanically rotated under a slit of equal in…

Storage of fungi in soil

Various fungi such as Cylindrocladium, Fusarium, Melanospaora, Nectria, Thielavia, Penicillium, Alternaria, Aspergillus, Rhizopus etc. Proved successful for storage in sterilized soil. 

Procedure to store fungi in soil 

Grow the culture on a suitable solid medium till it forms spores. 

Suspend the spores in 1 ml sterile water. 

Place garden soil in a bottle, autoclave twice and pour sterile water…

Microbial preservation in mineral oil

Pre-sterilized mineral oil or liquid paraffin or medical paraffin of specific gravity 0.83 – 0.89 g are used for preservation of microbes. It prevents dehydration and slow metabolic activity by reduced growth through reduced oxygen tension. This method is recommended for preservation of fungal cultures. 

Procedure of microbial preservation in mineral oil 

Grow the culture in suitable medium in a…

Streptococcus: Classification, Morphology, Isolation, Identification, Pathogenicity and Treatment

Streptococci are aerobic and facultatively anaerobic Gram-positive cocci, arranged in pairs, or chains. The enterococci are facultative anaerobes. They require complex nutrients for their growth. Streptococci and enterococci causing human infections. 

Streptococcus 

Streptococci are part of the normal flora in humans and animals. 

They are nonmotile, nonsporing, spherical or ovoid cocci, and…

Microbial storage in Gelatin Discs

In this technique, bacterial strains after growth is obtained and suspended in molten nutrient gelatin. The drops of the molten gelatin are allowed to solidify on Petri dish and allowed to dry over a desiccant. This method is easy to use and help to store the culture free from contaminants. This is recommended for preserving various species of Enterobacteriaceae, Staphylococci etc. Such as Pseudo…

Sampling of Bacteria from water

Direct microscopic examination of the water sample generally reveals few bacteria. The filtration techniques are used to isolate the bacteria for their estimation per unit volume, as well as to study them morphologically. The membrane filters provide a rapid and useful means of sampling from water. Such filters are also used for viable counting by laying on a suitable agar plate and allowing to…

Methods of Culture Preservation and Maintenance

Microorganisms are generally maintained by culture collection centers which are set up with the prime objective of conserving microbial diversity and valuable germplasm. The main goal of these culture collections is to act as a depository, supplying authentic microbial strains to researchers and to provide the strains for help in teaching. Sometimes these authentic cultures also help in the…

Staining of the fungi: requirement, procedure and result

The fungal propagules either are hyaline (colorless) or of different color. The hyaline mycelia / spores / conidia, etc. and their cytoplasm can be stained by using lactophenol and cotton blue. Cotton blue stains cytoplasm and results in light blue background. Lactophenol acts as clearing agent, whereas phenol as fungicides. For routine work of fungi identification, the commonly used stain is…

Isolation of the fungal pathogen from soil / diseased part of the plant

Soil is a reservoir of numerous microorganisms including fungi, bacteria and actinomycetes. According to their habit they may be saprophytes or pathogens. However, the fungal pathogens grow in soil and survive in the form of dormant propagules. Under favorable conditions fungal pathogens proliferate by utilizing organic material and increase their biomass. They infect the living plants of…

Isolation of phosphate solubilizing microorganisms from soil

Phosphorus is one of the vital nutrients for microorganisms next to nitrogen. Several species of bacteria (such as Bacillus spp. And Pseudomonas spp.) and of fungi (I.e. Aspergillus spp. And Penicillium spp.) degrade and solubilize the insoluble phosphates into soluble forms through the mechanism of secretion of organic acids e.g. acetic acid, glycolic acid, formic acid, lactic acid, succinic…

Demonstration of Carbohydrate metabolism (oxidation and fermentation of glucose) by microorganisms by Hugh-Leifson’s test

The microorganisms such as fungi, bacteria, actinomycetes, etc. Utilize carbohydrate as a source of carbon and energy through catabolism (enzymatic breakdown) and show growth and biomass production. However, utilization of carbohydrate is carried out aerobically (using molecular oxygen as electron acceptor for oxidation) and anaerobically (using inorganic ions, other than molecular oxygen as…

Catalase activity test for bacterial identification

Most of aerobes and facultative anaerobes have the characteristic of showing catalase activity. Actually, these organisms utilize oxygen to produce hydrogen peroxide. The hydrogen peroxide is toxic to their enzyme system. Hence, these organisms produce an enzyme catalase, which converts the hydrogen peroxide to water and oxygen. It is also that the reason of not surviving anaerobes in the…

Citric acid (citrate) utilization by bacteria: Requirement, Procedure and Result

This test is used for differentiation of E. coli with Enterobacter aerogenes. It is a widely acceptable test for testing the presence of E. coli, a fecal organism in water which cannot utilize citrate as carbon source while E. aerogenes can use it. Secondly, citric acid is an intermediate of metabolic product of Kreb’s cycle which oxidizes pyruvate to CO2. The bacterium must have an ability to…