Microbial Biomass Methods Review Test

Explanation
Chloroform fumigation incubation and substrate induced respiration are both physiological methods used to estimate microbial biomass. Chloroform fumigation incubation involves treating soil samples with chloroform to kill the microorganisms and then incubating them to measure the release of carbon dioxide, which is an indicator of microbial biomass. Substrate induced respiration, on the other hand, involves adding a substrate to the soil to stimulate microbial activity and then measuring the release of carbon dioxide. Both methods provide insights into the microbial biomass present in a given sample.

Explanation
Chloroform fumigation incubation is considered the standard reference technique to measure microbial biomass in soil because it involves fumigating the soil with chloroform to kill all the microbes, and then incubating the soil to allow the remaining microbial biomass to decompose the added substrate. By comparing the amount of carbon released from the substrate in the fumigated and non-fumigated soil, the microbial biomass can be determined. This method is widely used and has been validated through numerous studies, making it the preferred technique for measuring microbial biomass in soil.

Explanation
Substrate induced respiration refers to the process of estimating the maximum respiration rate that is induced by a specific substrate, typically glucose, within a short period of time. This method allows researchers to measure the respiratory activity of microorganisms or other biological systems in response to the presence of a particular substrate. By measuring the rate of respiration, scientists can gain insights into the metabolic activity and energy production of the organisms being studied.

Explanation
The suppression of the respiratory response to glucose in the SIR experiment can be used as an indicator to assess the toxicity of certain compounds. When the respiratory response is suppressed, it suggests that the compounds present in the soil may be toxic and affecting the metabolic activity of the microorganisms. This can be helpful in identifying and evaluating the potential harmful effects of specific compounds on the soil ecosystem.

Explanation
ATP determination is a method that relies on the luciferin-luciferase reaction for the measurement of biomass in soil. ATP (adenosine triphosphate) is a molecule found in all living cells and is considered a universal indicator of biomass. In this method, ATP is extracted from the soil sample and then reacted with luciferin and luciferase enzymes. This reaction produces light, which is measured and used to quantify the amount of ATP present in the sample. Since ATP is directly related to biomass, this method provides a reliable measurement of the amount of biomass in soil.

Explanation
The ATP Determination method involves direct measurements, which means that it directly measures the amount of ATP present in a sample. This method is also highly sensitive, meaning that it can detect even small amounts of ATP. It is specific for viable living cells, which means that it can distinguish between living and non-living cells. However, one limitation of this method is that it can be interfered by phosphorus levels in soil, which can affect the accuracy of the results.