為什么做氨基酸脫羧酶試驗需要做對照管
發(fā)布時間：
2022-12-27
作者：
瓶裝培養(yǎng)基與試劑廠家
氨基酸脫羧酶試驗在微生物生化檢測中是一項很重要的試驗，我們在做氨基酸脫羧酶試驗時，不僅要接種試驗管還同時要接種氨基酸脫羧酶對照管。
因為氨基酸脫羧酶試驗管中含有氨基酸和可以發(fā)酵的糖類（葡萄糖）。某些細菌在酸性厭氧環(huán)境，且有氨基酸底物存在的情況下能誘導產(chǎn)生氨基酸脫羧酶，使氨基酸脫羧產(chǎn)生尸胺，導致培養(yǎng)基變紫，而不產(chǎn)生氨基酸脫羧酶的細菌只能代謝葡萄糖產(chǎn)酸，使培養(yǎng)基變黃。
而氨基酸對照管中只含有可以發(fā)酵的糖類，不含有氨基酸底物。所以細菌只能代謝葡萄糖產(chǎn)酸，使培養(yǎng)基變黃。氨基酸脫羧酶對照管的作用主要是判斷待檢菌是否生長，且是否利用葡萄糖。
如果細菌本身不利用葡萄糖，對照管都是紫色的情況下，試驗管紫色就無法判斷是否細菌產(chǎn)生了氨基酸脫羧酶，使得培養(yǎng)基變紫。
實驗過程中如果我們遇到對照管紫色，但有明顯生長跡象的情況時，說明待檢菌可能不發(fā)酵葡萄糖，如假單胞菌，這種菌在檢驗過程中是有可能出現(xiàn)的。遇到這種情況，我們可以結(jié)合三糖鐵的結(jié)果，并補做氧化酶試驗，以此排除假單胞菌屬。假單胞菌的氧化酶試驗為陽性。
相關產(chǎn)品：氨基酸脫羧酶試驗對照培養(yǎng)基
Amino acid decarboxylase test is a very important test in biochemical test of microorganism. When we do the test of amino acid decarboxylase, we should not only inoculate the test tube but also inoculate the amino acid decarboxylase.
Because the amino acid decarboxylase test tube contains amino acids and fermentable carbohydrates (glucose). Some bacteria can induce the production of amino acid decarboxylase in the acid anaerobic environment and the presence of amino acid substrates, which causes the decarboxylation of the amino acid to produce cadavers, causing the medium to become purple, but the bacteria that do not produce amino acid decarboxylase can only metabolize glucose to produce acid and make the medium yellow.
Amino acids only contain fermentable sugars in the tube, and do not contain amino acids. So bacteria can only metabolize glucose to produce acid and turn the culture medium yellow. The role of amino acid decarboxylase is to determine whether the bacteria are growing and whether glucose is used.
If the bacteria themselves do not use glucose and the care is purple, the test tube purple can not determine whether the bacteria produce the amino acid decarboxylase, making the medium purple.
In the course of the experiment, if we encounter the condition of the care of purple, but there are obvious signs of growth, it is suggested that the bacteria to be tested may not ferment glucose, such as Pseudomonas, which may occur during the test. In this case, we can combine the results of three sugar iron and supplement oxidase test to eliminate Pseudomonas. The oxidase test of Pseudomonas aeruginosa was positive.