PLEASE ANSWER THE FOLLOWING QUESTIONS

- It is necessary for assessing the hygienic quality of semen. Such test depends
mainly on the fact that semen contains a very small amount of the hydrogen
peroxide splitting enzyme “Catalase”, and its presence in excess is an indication
to the presence of abnormal admixtures e.g., pus, blood, bacteria, etc.
- A special tube “the bromo-thymol-blue catalase tube” closed by a rubber plug
provided with a capillary tube.
- To 1 ml semen add 8 drops bromo-thymol blue 2% in 96% alcohol. The color
change is an indication to pH of semen where it is yellow at pH 6 and dark blue at
7.6.
- To the contents of the tube add hydrogen peroxide 3% to a special mark on the
wall. Put the plug and invert the tube. Examine after 5, 10, 15 and read after 20
minutes.
- If the amount of oxygen released above the column is more than 50 – 1000 µl,
semen sample will be considered of bad hygienic quality and in such case it will
be discarded.
2) Methylene-blue reduction test (MBRT):
- This test depends on the presence of dehydrogenase enzyme in the mitochondrial
sheath of the spermatozoa, centers of the metabolic activity, which is localized in
the middle piece. However, the rate of bacterial contamination influences the
reduction time as the enzyme is also present in bacteria.
- To nine parts of diluted semen with egg yolk-citrate add one part of MB 0.05%
(in citrate or phosphate buffered solution). Mix and suck into a glass capillary
tube, kept warm at 37C. Time of reduction of the methylene blue to
leucomethylene blue is estimated. Reduction within 5-8 minutes is an indication
to good quality semen.
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End of Model Answer
Best wishes
2012