Back to TopSymptoms Â». Hardening of the arteries does not cause symptoms until blood flow to part of the body becomes slowed or blocked. If the arteries to the heart become narrow, blood flow to the heart can slow down or stop. This can cause chest pain (stable angina), shortness of breath, and other symptoms.
A useful test to identify bacteria is a carbohydrate fermentation test. Fermentation is defined as an ATP generating process where organic compounds, in this case lactose, acts as both an electron donor and acceptor.A phenol red medium, with sucrose as the sole carbohydrate source, is used to detect fermentation.Phenol red indicator gives the medium a red-orange appearance. As lactose is fermented, acidic products are generated that causes the indicator to change from red-orange to yellow.An inverted tube (Durham tube) is sometimes placed in the medium to capture gas formed as a result of fermentation.henol red indicator gives the medium a red-orange appearance. As lactose is fermented, acidic products are generated that causes the indicator to change from red-orange to yellow. An inverted tube (Durham tube) is sometimes placed in the medium to capture gas formed as a result of fermentation.
Methyl Red / Voges-Proskauer (MR/VP). This test is used to determine which fermentation pathway is used to utilize glucose. In the mixed acid fermentation pathway, glucose is fermented and produces several organic acids (lactic, acetic, succinic, and formic acids).f the pH indicator (methyl red) is added to an aliquot of the culture broth and the pH is below 4.4, a red color will appear (first picture, tube on the left). If the MR turns yellow, the pH is above 6.0 and the mixed acid fermentation pathway has not been utilized (first picture, tube on the right).