Question

1) what causes nutrient mineralization by bacteria and what does it mean for the ecosystem?

2) how do biofilms benefit the microbes involved?

3) A recent paper stated " A. muciniphilia is also connected to barrier function of the intestinal mucosa by degrading mucin and disrupting the barrier function." but the paper they cited for this actually says "A. muciniphilia plays a crucial role in the mutualism between the gut microbiota and host that controls gut barrier function." Which player is right? Is consumption of muscin produced by the gut a disruption of its selective function? What is the damage to the host? if this is mutualism, name a specific benefit for the bacteria that isn't tru for all other gut bacteria. A mutualism here also requires a specific benefit. What is the benefit of bacteria degrading your protective mucin?

Answer 1

1. Nutrient Mineralization is caused when the bacteria present in soil decompose the organic matter (present in dead leaves,manure and other biosolids) into inorganic matter and the nutrients released in the process are used up by plants of the soil. It is beneficial for the ecosystem as it makes use of all the waste material present on the upper layer of soil and converts them into a form that can be utilized by the plants rooted in the soil.
2. Biofilms are formed in low nutrient concentration and as they are hydrophobic in nature they can concentrate ions and other carbon compounds into them. It provides a very good platform to microbes in promoting reproduction and grow in number successfully.
3. The first hypothesis saying about disruption of intestinal barrier, is correct.. Yes consumption of mucin is a disruption to selective function of gut. Because the mucin is produced by goblet cells in intestinal epithelium in form of a defence mechanism to protect gut from host. The host bacteria are trapped in the mucus layer and not allowed to reach epithelial walls of gut. They are eliminated from the gut by peristaltic waves of intestinal muscles. It is not mutualism, it is disruption of intestinal wall that allows the host bacteria to invade intestinal wall , making the wall permeable. It may result into unlimited colonization and growrh of host.