1. Effects of Nicotine on the Pulse Rate of Lumbriculus Variegatus
Materials:
Pitri Dishes (10)
Recovery dish (1)
Nicotine weigh boat for testing
Cold spring water
0.05mM nicotine solution
Stem pipettes (2)
Microscope
Custom welled slide
Stop watch (cellular phone)
Graduated cylinder
Procedure:
(15 second transfer)- transfer the worm, using a stem pipette, from the slide to the nicotine solution. Time it for 2 minutes (15 second transfer to the slide, and microscope (turn off between uses)-record the pulse for one minute
Establish which end of the worm is anterior and which is posterior (coloration).
Make observations of swimming/ crawling behaviors while the worm is in just spring water
(15 second transfer) remove the worm from the slide to the recovery
Set up two containers labeled “ #1/ nicotine solution 0.05mM” and “#2/ recovery dish”
REFERENCES:
Acquire 10 worms and 10 small sterile pitri dishes (label #1-20 with masking tape)
Place one worm into each pitri dish with just enough spring water, so that the worms can still break the surface to breathe
This article reprinted from: Bohrer, K.E Effects of drugs on pulsation rate of Lumbriculus variegatus(blackworms)Pages ,inTested Studies for Laboratory Teaching, Volume 27(M.A. O'Donnell, Editor). Proceedings of the 27th Workshop/Conference of the Association for Biology Laboratory Education (ABLE), 383 pages.
Acquire a timer (I used my cell phone)-place one worm onto the welled slide , prepared with a cover slip and place it onto the stage of the microscope (DO NOT turn on the microscope until you’re ready to use it; record the worm’s pulse rate for one minute
Introduction:
Lumbriculus Variegatus, commonly known as The Black Worm, is the focus of the following experiment, because it is a “Biological Smoke Detector”. By subjecting the worm to a 0.05mM Nicotine solution the experimenter can observe how nicotine may affect certain environmental areas; The Black Worm is good to determine the effects on areas of marshy and shallow fresh water. The pulse rate of the worm will be the data collected both before and after subjection to the stimulant substance, which can easily be observed as a wave of blood passes through the worm’s transparent body walls. We can also observe the worms other behaviors such as body reversal and clearly see the darker colored anterior (head) segment and the (tail) segment.
Nicotine Stock Solution
•Cigarettes - regular length and strength, NOT menthol, 100’s, or ultralights
•1.1mg nicotine/cigarette
•Make a 0.1mM stock solution by stirring the tobacco from 5 cigarettes in 340-ml of very warm spring water for 20 minutes. Filter the solution. You will lose about 50-ml of the solution when filtering. (HAD TO FILER 3 TIMES)
•Use appropriate amounts of the stock solution to make (C1 V1 = C2 V2) a 300 ML quantity 0.05 (medium) solutions.
Chemical formula: C10H14N2
Why is it considered lethal?
Nicotine is widely used all over the world in tobacco products, and products to wean user off of it, as it is highly addictive. However, it is also incredibly toxic and even lethal in high dosages. In high dosages it can be “corrosive to soft tissues and targets the nervous system incredibly fast”
Varied from original stock solution recipe due to results of a preliminary test.
Conclusion: The hypothesis was correct; when a group of 10 worms is subjected to a 0.05mM nicotine solution for 2 minutes, their average pulse rate shows an increase of 5.3/ minute average increase from their average pulse rates when submerged into plain spring water.
Spring water avg:15.5
Nicotine avg: 20.8
Hypothesis: If Lumbriculus Variegatus is subjected to a 0.05mM solution of Nicotine for two minutes then the average pulse rates of the experimental group will show an overall increase, compared to the pulse rates from being previously submerged in Spring water.
Dependent Variable:
Constants:
The worms pulse rate average before and after submersion in Nicotine
Same brand, and amount of spring water- same testing location and microscope- same testing time span-same slide- same type of pitri dish and pipettes-same transfer time and method -same timer- same welled slide.-
Control:
Pulse rates of worms subjected to Spring water with a stimulant will be compared to pulse rates of the worms before being submerged in nicotine, when they were in just spring water.
Independent Variable: the 0.05mM Nicotine solution