What is Auxanographic technique?

a method for the study of bacterial enzymes in which agar is mixed with the material (e.g., starch or milk) which is to serve as an indicator of the enzyme action and is inoculated and plated; if the bacteria produce enzymes digesting the admixed material, there will be a zone of clearing in the medium about each …

Who proposed Auxanographic technique?

Auxanography is the study of the effects of changes in environment on the growth of microorganisms, by means of auxanograms. It was first devised by Beijerinck for testing the effect of various nutrient media upon bacteria.

What are auxanograms?

Medical Definition of auxanogram : a plate culture (as of bacteria) in which variable conditions are provided for growth in order to determine the effects of a particular condition or agent on the growth of a test organism.

What is giant colony technique?

(i) Giant Colony Technique: This technique is used for isolation and detection of those antibiotics, which diffuse through solid medium. Species of Streptomyces, is capable of producing antibiotics during primary screening.

What is crowded plate technique?

The Crowded Plate Technique is the simplest screening technique employed in detecting and isolating antibiotic producers. It consists of preparing a series of dilutions of the source material of the antibiotic producing micro organisms, followed by spreading the dilution on the agar plates.

How do you screen microbes?

1. PRIMARY SCREENING OF ORGANIC ACID PRODUCING MICROORGANISMS The ph indicating dyes may be used for detecting microorganism that are capable of producing organic acids.
2. PRIMARY SCREENING OF ANTIBIOTIC PRODUCING MICROORGANISMS  Crowded plate technique is used for screening of antibiotic producing microorganisms.

What is gradient plate technique?

The gradient plate technique allows a gradual, proportional in- crease of drug concentration in the agar medi- um, extending over the entire cell monolayer. The slope of the gradient and the length of incubation do not seem to alter the results appreciably( 1).

How do you clean soil bacteria?

Bacteria were released and separated from soil by a simple blending-centrifugation procedure. The percent yield of bacterial cells (microscopic counts) in the supernatants varied over a wide range depending on the soil type.

What is quadrant streaking?

It is the common streaking method of isolating individual cells by preparing areas of dilution or quadrants. The colonies become thinner or isolated colony forms due to successive dilution of the inoculum by streaking the growth plate over four times.

What are auxotrophic mutants?

Auxotrophs are a group of organisms that lost the ability to synthesize certain substances required for their growth owing to the presence of mutations. Compared to the wild type strain, the auxotrophic mutants cannot grow in minimal medium if the corresponding nutrients are not supplied.

What is the advantage of gradient plate technique?

Another advantage of the gradient plate technique is that collective data could be used as a basis for determination of the growth/no-growth interface on a solid substrate, simulating the microbial contamination of food surfaces.

How do you know if microbes are living?

Re: How can I tell if my microorganisms are alive or not? The best way to find out if the amoeba and paramecium are alive is to look at them under the microscope and see them moving. The E coli and Bacillus you can spread on nutrient agar in a Petri dish and see if they form colonies.

What is the difference between auxotrophic mutant and resistant mutant?

An auxotrophic mutant will not grow when the essential metabolite (growth factor) is absent in culture medium; it grows and reproduces only when the required metabolite is supplied in the medium. Microbial Mutant: Type # 2. Resistant Mutants:

How much L-lysine does an auxotrophic mutant accumulate?

Each auxotrophic, double auxotrophic and triple auxotrophic mutants were separately cultured in 20 ml auxotrophic screening media in 100 ml flask and incubated at 28 C agitation 100 rpm. The other auxotrophic mutants accumulated 26.2 – 33 g/L L-lysine.

Do tryptophane and adenosine promote the growth of auxotrophs?

Auxotrophic mutants requiring tryptophane or adenosine (precursors of IAA and cytokinins) did not promote growth to the extent of the parent strains Inoculation of maize with Azospirillum brasilence and rice with A. lipoferum enhanced the uptake of phosphates, nitrate and ammonium.

Is there a biochemically marked cell line for auxotrophs?

The development of procedures for producing auxotrophic mutants in mammalian cells by Kao and Puck50 has provided several biochemically marked cell lines.