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.
Identification of Lactose positive and Lactose negative Bacteria using MacConkey agar. MacConkey agar contains bile salts and crystal violet to inhibit most gram + organisms.Lactose is a carbohydrate that may be used as a nutrient.