1 00:00:03,000 --> 00:00:11,000 (English captions by Andrea Matsumoto, University of Michigan.) [music] 2 00:00:11,000 --> 00:00:21,000 Step 1. Prepare the smear 3 00:00:21,000 --> 00:00:28,000 Prepare the smear by flaming the loop taking your inoculum from a fresh culture. 4 00:00:28,000 --> 00:00:35,000 After you have put on a drop of sealant on a slide. 5 00:00:35,000 --> 00:00:40,000 Take a culture, dip part of the inoculum in the culture. 6 00:00:40,000 --> 00:00:47,000 Take the culture and moistify it on the slide to join with the rest of the sealant to make 7 00:00:47,000 --> 00:00:54,000 a smear of about two to three centimeters. 8 00:00:54,000 --> 00:00:59,000 Step 2. Gently heat fix the slide (after it has air-dried.) 9 00:00:59,000 --> 00:01:05,000 So, after air-drying, heat fix the smear by passing it through the flame about three or 10 00:01:05,000 --> 00:01:07,000 four times. 11 00:01:07,000 --> 00:01:12,000 This makes the organism to die or kill the organism. 12 00:01:12,000 --> 00:01:18,000 Allows you to stick onto the slide and then prevents autolysis and makes the organism 13 00:01:18,000 --> 00:01:21,000 permeable to the stain. 14 00:01:21,000 --> 00:01:25,000 Step 3. Flood the smear with crystal violet 15 00:01:25,000 --> 00:01:36,000 Flood the smear with crystal violet for one minute. 16 00:01:36,000 --> 00:01:42,000 Allow it to stain for 60 seconds. 17 00:01:42,000 --> 00:01:58,000 Tip off the excess crystal violet stain and wash under gentle tap water. 18 00:01:58,000 --> 00:02:05,000 Step 4. Flood the slide with Lugol's iodine solution 19 00:02:05,000 --> 00:02:14,000 Cover the smear with Lugol's iodine for one minute. 20 00:02:14,000 --> 00:02:18,000 Allow it to stain for 60 seconds. 21 00:02:18,000 --> 00:02:22,000 Wash off the excess Lugol's iodine stain with gentle tap water. 22 00:02:22,000 --> 00:02:31,000 Step 5. Decolorize briefly with acetone. 23 00:02:31,000 --> 00:02:40,000 Decolorize the smear with acetone for ten seconds. 24 00:02:40,000 --> 00:02:52,000 Tip off the excess alcohol and wash under tap water, gentle tap water. 25 00:02:52,000 --> 00:02:58,000 Step 6. Counterstain with neutral red (or safranin). 26 00:02:58,000 --> 00:03:03,000 Use neutral red to counter-stain for one minute. 27 00:03:03,000 --> 00:03:07,000 Cover the smear with the neutral red. 28 00:03:07,000 --> 00:03:14,000 Allow it to stain for 60 seconds. 29 00:03:14,000 --> 00:03:26,000 Wash off the excess neutral red under tap water. 30 00:03:26,000 --> 00:03:31,000 And blot it dry with a filter paper or a blotting paper. 31 00:03:31,000 --> 00:03:36,000 Don't wipe. 32 00:03:36,000 --> 00:03:48,000 The slide is now ready to be examined microscopically at 100X (oil immersion). 33 00:03:48,000 --> 00:04:01,000 Put oil immersion on the slide where the smear is. 34 00:04:01,000 --> 00:04:04,000 And put the slide under the microscope. 35 00:04:04,000 --> 00:04:08,000 We are using the five hundred objective (500X zoom). Examine the slide.