In 1884, Hans Christian Gram, Danish bacteriologist,
tried to find a universal stain that will work with all the bacteria. During >> << He found that bacteria can be divided into two groups
preserved spot, called "gram-positive" and one that did, in
-- called "gram-negative." His unique method of identifying these two groups
the first step in any process of bacterial identification. Even a simple definition >> << that bacteria or gram-negative gram-positive sample may
direct physician in diagnosis as well as various bacteria cause different diseases. For example, bacteria that cause scarlet fever is a gram-positive, while >> << that causes typhoid or cholera gram-negative. Gram staining helps doctors diagnose but can
this will also offer treatment? What is the relationship between grams
classification and use of antibiotics? As usual antibiotics interact
different gram-positive and gram-negative bacteria? Answer these questions
experimentally. Q: Will the four common antibiotics (penicillin, ampicillin and neomycin
, erythromycin) have the same effect as
Gram-negative and gram-positive bacteria? Follow / Data Collection: Do some research to find
information about antibiotics and Gram-negative staining, so you can make
reasonable hypothesis. Hypothesis: Based on your research, write more >> << hypothesis prediction of response to this question. Experiment: an experiment to test the hypothesis
need two parts. In the first part, do gram stain for bacteria cultures to determine which are gram-negative
and that gram-positive. The second part of a controlled experiment
measure the impact of each antibiotic for each type of bacteria. Working with chemicals and bacteria can be dangerous. Before you begin
read it. Part One - Gram materials live bacteria cultures - and. (You can also
cultures (containing crystal violet
spots, stains gram iodine ethanol solvent safranina O
contrasting colors, simple microscope slides, pipette, cover)
Procedure Some steps Gram process is difficult to perform well. To practice, it is a good idea to "control" slide.
Try to collect some bacteria between the teeth (with toothpicks) and
putting it on a glass slide with a drop of water . If gram staining procedure
done correctly, the slide should have a mixture of gram-negative and gram
-positive cells as well. some neutrophils (white blood cells) with pink cores >> << After you've tried that spot each live bacteria cultures
using the following procedure:
sterilize your vaccination needles, placing it in the flame.
Let cool for 3 -5 seconds.
Make a swab sample by placing a small amount of bacteria from one Culture >> << on a clean glass slide with a needle inoculation. Take another slide and
use its land to clear or "smudge" the sample in a thin film material >>.
<< Let the sample on the slide air dry and heat fix by passing slide through flame >> << ' I candles 3-4. (slide should not become too hot to touch, and
never have to stop as it passes through the flame).
, Cover the sample with 1-2 drops of crystal violet stain for 60 seconds
and then gently rinse slowly running water from the tap or more
delicate bubbles from washing. bottle (if water is running too fast and hits
slide too much force , the sample will be washed off).
cover design with a few drops of iodine Gramm for 60 seconds and then gently rinse the sample again, as in step
4. Using ethanol as solvent. This is the most sensitive step, because if
ethanol left in the sample is too long, it will light
Gram-positive cells and Gram-negative. Tilt slide gently

use alcohol by drops on the slide above the sample, so that alcohol
flowing across the sample. Stop using alcohol as liquid
flows from the edge of the slide is not color.
small part of the smear should be colorless. It takes about 5 seconds. Wash the slide gently again. Note that Gram-positive cells retain some of the purple color, but most >> << stains will wash solvent.
Cover the sample with a few drops safranina spot as counter stain
for 60 seconds and then gently rinse again. Blot
slide with filter paper (paper towel will work if you have nothing else
), but not to rub the sample smear. Put the cover on the smear. Now you are ready to consider a slide under a microscope each increasing level >>.
, << How do so, look at the cells purple. This gram-positive cells
are kept crystal violet stain. Cells pink or red color
are gram-negative cells. In these cells, crystal violet was washed
on ethanol and replace .. safranina Once you have determined which of your living cultures and gram
a gram-positive, clearly mark it and move to the next part of the experiment
Part two - antibiotics One way to test bacteria sensitivity to antibiotics is to use
Kirby-Bauer or "disk diffusion" method. This method consists in measuring
suppress the growth of bacteria in All antibiotic disc placed in
culture. Materials 2 sterile (penicillin, ampicillin, neomycin
and erythromycin)
agar preparation procedure as directed on the label, then strattera dosage pour 10-15 ml
in each Petri dish (enough to cover bottom of dish). >> << Let dish stand (covered) for about an hour until the agar firm. sterilize your needle inoculation, and then instill one dish with >> << gram-positive bacteria. slightly zigzag needle over the surface >> << agar, turn the dish, and do it again. Do this several times to get the maximum
distribution. Place one disc each type of antibiotic in various places on the agar >> << (used sterile forceps). Press down gently drive
secure it in agar. Cover the dish when you're done. Repeat steps 2-3 with gram-negative bacteria. Examine each dish after 24 hours. If bacteria culture grows
until the edge of the disc antibiotic, it is not exposed to that antibiotic.
If there is a circular zone around the disk, where
slows growth of bacteria, measurement and keeping the diameter of the circle. Note the effect of each antibiotic disk in each Petri dish.
You can also shoot. Repeat step 5, after 48 hours. When you have finished your observation of cultures of bacteria, put a tablespoon >> < <household bleach in a bowl, cover them, seal them in a plastic bag and throw
them. Data Analysis / Data Analysis Summary form. How do each antibiotic in every culture bacteria >> <<? Were more effective antibiotics against gram-positive or general
? Gram-negative bacteria? What are the limitations of your research? Can you get more accurate results if you feel more bacteria culture
form of imprisonment. your results support your hypothesis why
or why not? What results tell you about the process
antibiotics and how you could extend this study to learn more about
relations antibiotics and bacteria? Security Notice often chemical substances used to prepare slides >> << can be toxic, corrosive and other hazardous phenomena associated.
Always carefully read entire label before using chemicals. Make sure you understand
dangers proper safety equipment to wear and what you do
if spill or contact with skin. stains for gram stain process
will discolor clothing and skin. Key you
should wear safety glasses include (such as surge), chemically resistant gloves, chemical resistant lab apron. work in a clean, well ventilated,
concise, where you can quickly wipe spills. Always store chemical bottle tightly closed. Do not operate antibiotic disks, if you are allergic to those forms of antibiotics.
bacteria, you can use
danger. Always thoroughly wash your hands before and after treatment
cultures of bacteria. Styralnaya them before will minimize pollution >> << cultures of bacteria you are growing. Styralnaya them would then be to minimize the impact
harmful bacteria that can grow in your culture. When you have finished studying culture
, pour enough household bleach in it to cover the bottom
dish. Then, cover crops, seal it in a plastic bag and discard.