Define psychrophile and halophiles bacteria What happens to

Define psychrophile and halophiles bacteria

What happens to cells when they are in a high osmolarity solution?

Define: antagonistic effect, synergistic effect, symbiotic effect

What is a “clean catch” method of collecting urine from a patient?

Define: selective media, differential media, and complex media for bacterial growth

What exactly is lyophilization?

How does the technique that uses turbidity to estimate the growth of bacteria work?

Solution

Psychrophile bacteria are the ones which can survive and reproduce in extreme cold temperatures ranging from -20° to +10°C by reduced enzyme activity, decreased membrane fluidity, decreased rate of cell division etc. Halophilic bacteria survive and reproduce in saline environment. They can accumulate ions like sodium ions, potassium ions, chloride ions to balance out the osmotic pressure of the medium. They also have some specific proteins that remain active in the presence of salt.

High osmolarity solution indicates that the medium must be hypertonic compared to the cell which is placed in it. Thus dolvent molecules will move out of the cell by the process of exosmosis resulting in the shrinkage of the cell.

Antagonistic effect is a phenomenon where two or more agents (chemicals) in combination have an overall effect less than the sum of their individual effect. For example in our body, two hormones Insulin snd Glucagon are antagonistic yo each other. Insulin helps in the conversion of glucose to glycogen while Glucagon helps in conversion of glycogen to glucose.

Synergistic effect is a phenomenon where two or more agents (chemicals) in combination has a greater effect than the sum of their individual effect. For example alcohol and cocaine combine to form cocoethylene which is removed from the body more slowly than either ethanol or cocaine. Also toxicity of cocoethylene is much higher compated to ethylene or cocaine alone.

Symbiotic effevt is a phenomenon where two agents stay in close association. From this association one of the organism will benefit and the other remain uneffected or both may be benefitted from each other and help each other out in several reactions. For example it has been found that some bacteria like Lactobacillus paracasei improves the lymphocyte count and proinflammatory cytokines to protect from intestinal inflammation in humans.