Gram Staining Bacteria

Strep. Agalactiae
The genus Streptococcus is classified as a gram positive bacteria because of the spherical or ovoid
cells that often arranged in pairs and the color it turns too after undergoing the gram staining
technique. Unlike the catalase positive genus Staphylococcus, Streptococcus is catalase negative
(Fox). Many Streptococcus bacteria are known to be facultative anaerobes, meaning they prefer to
grow in places that have no oxygen but will adjust to places that contain some oxygen (Holt, et al.).
On the contrary, there are a handful of Streptococcus bacteria that are considered to be obligate
anaerobes, meaning they are strictly prohibited from being around oxygen because they are unable
to live. Growing this type of bacteria includes specific factors ... Show more content on
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Viridians Streptococci is commonly found in either the mouth, gut or genital region. They are a
heterogeneous group that are also called "green streptococci" because of the green color it produces
on blood agar plate ("Streptococci"). This bacteria is associated with dental caries and pericoronitis,
an inflammation of the soft tissues surrounding the crown of a partially erupted tooth (Fox). This
bacteria is the type of infection can be serious when the bacteria begins to enter other regions of the
body (Robinson). Dental diseases associated with transient bacteremia can be predisposing factors
for endocarditis, which is an infection of the inner lining of the heart (Patterson). Treatments for
severe infections like this, may include intensive treatment with intravenous antibiotics for at least
ten days. If it worsens, surgery may be required to remove or repair the damage tissue
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Gram Staining Procedure
Bacterial identification procedures are extremely important in the clinical laboratory.
Microorganisms need to be classified, and identified in order to distinguish one species from
another. Identification can isolate organisms that are disease agents, and enable physicians to make
diagnosis's. It also enables physicians to choose the best treatment/antibiotics to address that specific
organism. For example, some gram negative bacteria can produce endotoxins when they die, which
would be of concern to a doctor prescribing antibiotics. Identifying a specific bacteria as a source of
a disease is the first step in moving towards discovering how it can be transmitted and preventing
reoccurrence. Species can be distinguished by morphology and ... Show more content on
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This staining procedure was developed in the 1882, by a Danish bacteriologist, Hans Christian
Gram. This technique identifies differences in a bacteria's cell wall. It utilizes crystal violet (primary
stain), Gram's iodine (mordant), and safranin (counterstain). Most bacteria fall into two categories,
Gram positive or gram negative. Gram positive bacteria have a thick layer of peptidoglycan, and
techoic acids in their cell walls. This thick peptidoglycan layer retains the crystal violet stain, and
displays the cells as a purple color under the microscope. Gram negative bacteria cell walls have
significant differences from gram positive bacteria. Gram negative cells have a thin peptidoglycan
layer, and do not have techie acids. They also have an outer membrane that is similar to the
phospholipid bilayer of a cell membrance. These differences allow the crystal violet stain to rinse
away from them, then they retain the safranin stain and appear reddish/pink under the microscope.
Although it is very useful, it is not the only tooled needed to identify a bacteria. Some bacteria, are
gram–variable, displaying both positive and negative reactions. Other bacteria, such as
Mycoplasmas, do not have a cell wall, rendering this test ineffective. Finally, it does not provide
enough information alone to identify a

Gram Staining Lab Report
This week in Lab 3 we will be discussing and practicing simple and gram stains. Staining is the
process of making bacteria visible to isolate and experiment with. Staining helps to show the
bacteria in a color so it is no longer clear by increasing the contrast of the specific organism.
Staining is used in the medical field not just to look at bacteria and cultures but also for diagnostic
purposes. It can be used to highlight certain tissues and even specific parts within a tissue. There are
many different types of staining, including: Acid fast staining ( Ziehl – Neelson Technique),
Acridine orange stain, Auramine – Rhodamine technique, Calcofluor white stain, Capsule stain,
Cytoplasmic inclusion stain, Endospore stain, Giemsa stain, Flagilla ... Show more content on
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The smear concentration will directly affect the gram results by making a false positive or false
negative gram positive stain. Take the slide smears and put them in crystal violet solution for one
minute. Rinse all of the stain off with water. After all the water has been removed from the slide,
place it in the mordant which is Grams iodine solution. A mordant is an inorganic oxide that
chemically reacts with the dye and affixes to the cell. Rinse the solution off with water the same way
we did before and then place the slide in a decolorizing agent for 10–12 seconds. As not to wait for a
long time, rinse this off with water as well. Waiting to wash the decolorizing solution off will clear
all the dye of off the previously dyed cells. Put the slide in the counter stain safranin for one minute
and rinse with water. Place the slide on bibulous paper and wipe an access water of the slide being
careful not to disrupt the bacterial culture. Now that the slide is done, put it under the microscope
with an oil immersion to view under 100x magnification. Gram positive bacteria is blue or purple
and gram negative bacteria is red or

Gram staining is a way of classifying bacteria into two groups: gram–positive and gram–negative.
The experiment conducted allowed for distinguishing of two specimens, Bacillus subtilis and
Escherichia coli, using several dyes to distinguish the two. The experiment revealed the culture of B.
subtilis to be a Gram–Positive organism and E. coli to be a Gram–Negative organism. Introduction
Cell staining is a method that can be used to view cells and cell components with a microscope. The
structure of the organism's cell wall determines whether the organism is gram positive or negative
when stained. In addition, staining also allows for one to identify cell size, shape and arrangement.
Gram–positive cells have a thicker peptidoglycan cell wall to which the stains are ... Show more
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coli / B. subtilis, glass slides, transfer loops, a Bunsen burner, gram's stains and alcohol) to
successfully complete the experiment. Aseptic technique was used and maintained during the entire
experiment by utilizing the Bunsen burner. I began by labeling two slides and adding a small drop of
water to each slide. Immediately after adding water and maintaining aseptic technique, I smeared
samples of bacteria to each slide, one of which received a sample of B. subtilis and one that received
a sample of E. coli. My next step was to begin staining the slides with a primary stain such as
Crystal Violet for 2 minutes then rinsing it with water afterward. Next, I placed the mordant (gram
stain dye) on the slides for 1 minute and rinsing with water afterward. Subsequently, I used a
decolorizer (95% ethanol) for 10 seconds to remove the dyes from each slide, followed by rinsing
with water immediately and patting each slide dry. Finally, I added a counterstain(safranin) to help
distinguish the slides although this step is not a necessity for gram staining. After conducting the
staining techniques, the slides were now ready for

Lab Report : An Unknown Microorganism Using Lab Techniques
Unknown Lab Report
Unknown #27
Rona Hakaj
12/08/2014
Dr. David Mwangi
Microbiology
Spring /2014
3305–04
Introduction: The purpose of this lab was to identify an unknown microorganism using lab
techniques. The importance of identifying microorganisms is essential to the survival of humans,
expansion of modern day medicine and improvement of quality of life. In 1884, Hans Christian
Gram designed a differential staining technique to identify bacteria that would change the future of
microbiology. He give rise to a staining process, known as the Gram stain to differentiate
microorganisms into two groups between positive and negative gram staining microorganisms. The
Gram stain is essential in a lab technique as it distinguishes the cells based on the physical
properties of the individual cell walls, and is almost always the first test preformed to differentiate a
microorganism. The identification of weather a microorganism is gram positive or negative can
revel the bacteria's virulence, cell wall structure, resistance to antibiotics, resistance to physical
disruptions and so much more. In order to identify the unknown provided, unknown #27, the Gram
stain was the first test preformed. After discovering that the unknown bacterium was indefinitely a
gram positive microorganism, the vast possibilities were narrowed down. However, In order to more
definitively identify the unknown, the next step was to preform biochemical tests. A biochemical test
identifies metabolic

Gram Staining Procedure
Staining of bacteria forms the foremost and the most important step in the identification of bacteria.
Gram staining: differentiates bacteria into two types Gram positive and Gram negative bacteria
Gram positive bacteria can be either cocci or bacilli or vibrios. Gram negative bacteria can be either
cocci or bacilli.
Motility testing
Motility testing is performed by preparing a wet mount and is then observed under the microscope.
Biochemical tests
The staining will be followed by use of various biochemical reagents and tests to get closer to the
identification of bacteria. There are many biochemical tests available for bacterial identification.
The biochemical tests that will be used for identification of Bacillus spp. are as mentioned below ...
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A positive diagnostic test rests on the generation of alkaline by–products of citrate metabolism.
Procedure
Use a fresh (16– to 18–hour) pure culture as an inoculation source. Pick a single isolated colony and
lightly streak the surface of the slant. A needle is the preferred sampling tool in order to limit the
amount of cell material transferred to the agar slant. Avoid using liquid cultures as the inoculum
source. Citrate utilization requires oxygen and thus screw caps, if used, should be placed loosely on
the tube. Incubate at 35oC for 18 to 48 hours. Some organisms may require up to 7 days of
incubation due to their limited rate of growth on citrate medium.
Citrate positive: growth will be visible on the slant surface and the medium will be an intense
Prussian blue. The alkaline carbonates and bicarbonates produced as by–products of citrate
catabolism raise the pH of the medium to above 7.6, causing the bromothymol blue to change from
the original green colour to

The Role of Agarase in Agar-Degrading Bacteria
The Role of Agarase in Agar–Degrading Bacteria
Abstract
Agar–Degrading (agarolytic) Bacteria is physiological class of bacteria capable of utilising agar as a
sole carbon source. This ability is made available by the use of agarases – enzymes which break
down agarose into oligosaccharides. This physiological class branches through genii, regardless of
Gram Stain status or morphology. Through a review of scientific literature we can find identification
methods, optimum conditions and the general function and location of agarolytic bacteria, as well as
methods to culture them in vitro for study and experimentation.
Agar is a gelatinous substance derived from algae and seaweed that has found considerable use in
laboratories as ... Show more content on Helpwriting.net ...
In addition, a study of the effects of phosphate limitation on agarase shows that limiting phosphate
increases both intracellular agarase production and extracellular secretion, whereas a magnesium
limitation does not (9). This further highlights the niche which this class of bacteria usually
occupies, as the concentration of glucose or phosphate in the ocean is very low while magnesium
concentration is generally much higher, suiting the agar–degrading bacteria's agarase production;
there is simply no need to use glucose in the ocean, so many organisms can't.
In Vitro Culturing
Knowing the conditions agar–degrading bacteria accommodate in situ, it is possible to approximate
similar conditions in vitro. Leon et al achieved this by spreading samples of sea water on agar plates
containing 0.25% casein hydrolysate, 0.05% yeast extract, 2.5% NaCl, 0.06% NaH2PO4, 0.5%
MgSO4, 0.002% FeSO4∙7 H20, 0.01% CaCl2 and 1.5% Agar with a pH of 7.25 and incubating them
for 48 hours at 25°C(6). After 48 hours, single colonies that had made small pits in the agar (thus
indicating the presence of agarase) were inoculated onto new plates with the same conditions as
above. The aim of this selective and differential process is to ensure a pure culture, as non–
agarolytic bacteria should not be able to survive the first plate, let alone a second one. This
inoculation

How to Write a Lab Report in Microbiology
HOW TO WRITE AN UNKNOWN LAB REPORT IN MICROBIOLOGY GENERAL Unknown
reports in microbiology are written in scientific format. Scientific writing is written differently from
other types of writing. The results of the exercise or experiment are what are being showcased, not
the writing. The purpose of scientific writing is not to entertain, but to inform. The writing should be
simple and easy to understand. There is a specific style that must be followed when writing
scientific reports. Scientific writing is typically written in the passive voice. The pronouns "I", "We"
and "They" are not typically used.. For example, instead of writing "I used a TSA agar plate to
isolate my unknown," it is customary to write, "A trypticase ... Show more content on
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Note all of these tests were performed by the methods listed in the lab manual by De Mers (1). Table
1 lists the test, purpose, reagents and results. All of the following tests were performed on this
unknown: 1. Oxidase test 2. BCP Lactose 3. Indole 4. H2S 5. Citrate 6. Motility 7. Methyl Red 8.
Urea" Another way is to write out the methods in detail in either a paragraph form or listed. This
way is not necessary for this type of paper, since this is lab report for the identification of an
unknown bacterium and the methods are explained in detail in the lab manual. If there is a procedure
that the instructor added or made changes to, or the student used another procedure not in the course
lab manual, then it should be written out and referenced. See some of the examples of papers
identifying an unknown from the web sited below. RESULTS This is where the results are
summarized. The method results should be in a table format (see examples below). This is also
where the flow chart showing how you arrived at the answer is stated. A short paragraph explaining
how the results are presented can be included. Example: Unknown G had the following morphology
on a TSA plate: medium sized opaque cream colored colony. After determining that it was a Gram
negative rod, an oxidase test was performed and it was inoculated into a BCP lactose tube

What Is Gram Staining?
Gram Stain
In 1884, a Danish pathologist, Christian Gram, discovered a method of staining bacteria with
pararosaniline dyes. By using two different dyes, he discovered that bacteria fall into two different
groups. The first group, gram positive, retains the primary color, crystal violet. The second group,
gram negative, when washed in a decolorizing solution, becomes colorless and takes on the color of
the counterstain.
The reaction of the Gram–stain in a bacteria is determined by the biochemical composition within
that bacteria. Gram–positive cell walls are composed of tightly linked peptidoglycans which traps
the iodine complex, thus retaining the violet color after decolorization is complete. Gram positive,on
the other hand, have a

Streptococcus Pneumoniae, Causes Pneumonia, And Upper Lobe...
Streptococcus pneumoniae, (cause pneumonia, and upper lobe lesions)
Klebsiella pneumoniae,(cause pneumonia, cause destructive changes to lungs, leading to rise the
respiratory rate)
Haemophilus influenzae, (cause pneumonia, opportunistic with alcoholism can lead to enlarge the
liver)
Moraxella catarrhalis, (cause pneumonia, pathogen with an affinity for the human upper respiratory
tract)
Staphylococcus aureus, (cause pneumonia, it usually affect patient with chronic illness)
Legionella pneumophila, (cause pneumonia, it effects the temperature raising of the body)
Organism: Klebsiella pneumoniae
Reason: Bacterial pneumonia are rare in healthy host and usually occur in young children, the
elderly, in alcoholics. The 60 year old man with severe chronic alcoholism is affected by the bacteria
Klebsiella pneumoniae, because Klebsiella pneumoniae explains the lobar pneumonia particularly in
the upper areas of the lungs where the man's infiltrates has been detected, Pneumonia procured from
Klebsiella pneumoniae, is characterized by high fever, chills, chest pain and cough (Medicine,1997)
. The patient in question has few symptoms related to this bacterium. The fever, raised his body
temperature to 103 ºF and, the respiratory rate of 36 per minute which was caused by pneumonia.
Klebsiella pneumoniae is a gram negative bacterium so gram staining of the sputum would be a
good place to eliminate all the gram positive bacterium.
However it has been reported this test has a

A Series Of Biochemical Tests
A series of biochemical tests were conducted in order to determine the identity of an unknown gram
negative bacterium. The unknown had the potential to be one of six different gram negative bacteria:
Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Proteus mirabilis, Klebsiella
pneumonia, or Salmonella typhirmurium. After using the T–streak method to isolate pure colonies
and confirming the gram negative nature of the unknown bacterium the unknown was subjected to
seven biochemical tests and the results compared to the results of the six known bacteria for the
same tests. After performing the Triple Sugar Iron Agar Test, Sulfur Indole Motility Test, Methyl
Red Test, Voges–Proskauer Test, Citrate Test, Urease Test, and Gelatin Test it was confirmed that
identity of Unknown #15 was Salmonella typhirmurium.
While all bacteria retain basic qualities identifying them as prokaryotes they do not function, grow,
or even metabolize in the same way. These differences distinguish bacterial species from one
another, like a thumb print identifies a single individual from every other person on earth. Testing
for these unique factors through a series of biochemical tests and staining techniques allows for an
unknown bacterial strain's "thumb print" to be generated. From there the unknown's thumb print can
be compared to the thumb print of known bacterial species allowing for identification.
The first step in identification is performing a Gram Stain. Due to the fact

Isolation of Pure Cultures by Dilution Techniques and Gram...
Isolation of Pure Cultures by Dilution Techniques and Gram Staining Method
Results
Table 1. Gram stain reaction and cellular features of the culture.
Gram staining methods were applied on the given mixture of Bacillus cereus,
Escherichia coli and Staphylococcus aureus and then examined microscopically. Results were
recorded in Table 1.
Gram Reactions Cell shapes Cell Ends and Arrangement Size Distinctive Characters Predicted
Bacteria
Bacteria 1 Gram positive (purple) Cocci Rounded, clusters, singly Small – Staphylococcus aureus
Bacteria 2 Gram negative (pink) Rods (shorter than B. cereus) Rounded, regular, pair, clusters
Medium – Escherichia coli
Bacteria 3 Gram positive (purple) Long rods Rounded, irregular, groups, chains Large ... Show more
A complex between crystal violet and iodine (CV–I) is formed within the cell. The structure that
determines the Gram reaction is the cell wall structure and not that shape. Bacillus cereus and
Staphylococcus aureus are stained purple in the Gram staining as they have a high amount of
peptidoglycan which forms the outer layer of the cell. This thick peptidoglycan layer is able to trap
the purple CV–I complex even after alcohol treatment. Escherichia coli is stained pink in the Gram
staining and it is a Gram–negative bacteria. Gram–negative bacterias usually have a thin
peptidoglycan layer compared to Gram–positive bacterias. The peptidoglycan layer is located
between the plasma membrane and an outer membrane containing lipopolysaccharide and this outer
layer is dissolved during the alcohol treatment which results in a loss of the CV–I complex, hence
the pink safranin counterstain is trapped by the peptidoglycan layer (ASM, 2004). Gram staining
allows us to observe the characteristics and cell size, shape and arrangement. For Bacillus cereus,
endospores were also viewed during microscopic observation. During Gram staining, the most
crucial step in determining the outcome is the decolourisation by alcohol step. If alcohol is applied
too long, the alcohol may wash all the CV–I complex that is trapped in peptidoglycan layer.
Therefore, alcohol is only applied for 30 seconds

Gram Staining Essay
A gram stain is a simple way to begin differentiating an unknown bacterial sample. Bacteria may
either be gram–negative or gram–positive. Staining makes bacteria cells visible, and this particular
staining method allows us to narrow down whether the bacteria in gram–negative or gram–positive.
Gram–negative stains purple and gram–positive stains pink.
Gram staining is used by students in advanced placement biology high school courses and in college
microbiology courses. Gram staining is conducted in a laboratory, whether it is a research lab or a
classroom lab. Instructors and professors will have the following items on hand for you.
CAUTION: Open flame or heat may be used, follow proper precautions to avoid a fire or injury.
Staining technique ... Show more content on Helpwriting.net ...
Staining technique uses dyes that are non–toxic but produce difficult to remove stains from skin and
clothes, wear gloves to avoid staining on hands.
Once you have gathered all your materials, you may start with the procedure. Before starting with
the actually staining, wash your hands and wipe down your work area to avoid contamination. After
that is done turn on your source of heat. Often times the source of heat will be a Bunsen burner, so
in order to turn a Bunsen burner, use a gas hose to connect the burner to the gas line. Once
connected, turn the gas line all the way on and place the fire striker close to the opening and strike it
to start a flame. Then minimize the flame by slightly closing the handle. After your source of heat is
ready to go, you can start the staining process.
1. Get one of the microscope slides and place it on a flat surface. Add about 6 drops of distilled
water to it
2. Sterilize the metal loop in flame until it turns orange. Make sure only the wire loop part is being
heated so you avoid the whole tool getting hot and burning yourself. Remove the loop from the
flame and let it cool for about three

Bacteria Classification by Gram Staining Essay
Bacteria Classification By Gram Staining
THE AMERICAN UNIVERSITY IN CAIRO
BIOLOGY DEPARTMENT
SCIENCE 453 : BIOLOGY FOR ENGINEERS REPORT No.1
Presented By : Karim A. Zaklama 92–1509 Sci. 453–01
24/2/96
Objective:
To test a sample of laboratory prepared bacteria and categorise it according to Christian's gram
positive and gram negative classes and also by viewing it under a high powered microscope and oil
immersions; classify its shape and note any special characteristics.
Introduction:
Bacteria was categorised into two groups in 1884 by the Danish
Bacteriologist Christian, gram positive and gram negative by a staining technique where the ability
to avoid de–coloration of Crystal Violet solution by alcohol would render the category ... Show
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11. Leave the slide to air dry.
B. Examination:
1. Place the slide under microscope on low powered lens. 2. Move the slide using the apparatus until
the sample can be seen as a blur under the microscope.
3. Focus the lens to ensure that there is a sample directly under the lens. 4.
Move to higher powered lens, repeat step 3. 5. Move to higher powered lens, repeat step 3 6. Move
microscope aside and add Oil immersion, leave for a few seconds and re–examine the slide.
Note Shape and colour and any other observations.
Results and Observations:
It was evident by visual examination that the alcohol was de–colouring or a least partially de–

colouring the bacteria. The sample appeared a dark pink or close to violet by the naked eye; a
microscope was needed to ensure results. Under the low powered microscope shades of pink were
noted. Under the medium power, the shades were more clear but no shape could be made out. Under
the high powered microscope clumps of pink rod (bacilli) shaped bacteria cells could be observed.
Under Oil Immersion and high powered lens the cells could seen more spaced out and thus a clearer
indication of the pink colour, bacilli shape and spores could be made out in the individual cells.
Conclusion:
The Shape was noted as Bacilli (Rod–like) shaped cells; a gram variable shape, distinct in either
Gram Negative or Gram positive bacteria. The final colour of the cells were stained pink by

Lab Report For The Purpose Of Gram Staining
Gram Staining
Formal Lab Report
Miranda King
Intro Microbiology
Dr. Hendrickson
13 September 2017
Purpose
For the purpose of the gram staining experiment was to learn this specific type of staining technique,
as well as learn how distinguish the differences between Gram positive and Gram negative stains.
This technique uses crystal violet stain, Gram's Iodine, Ethyl Alcohol, and Safranin. These dyes are
used in order to distinguish between the different types of cells. For example, Gram positive staining
will result in a purple color, and Gram negative staining will result in a red or pinkish color
(University of Central Oklahoma department of biology, 2016). When a bacteria results in a purple
stain it is categorized as a gram–positive stain because the alcohol that was used to decolorize the
bacteria was not successful. Its' cell wall is made with a thick layer of peptidoglycan and holds the
crystal violet color (Case, Funke, & Tortora). When a bacteria results in a red or pinkish color, this
means that it loses the crystal violet dye color after being decolorized and keeps the Safranin dye. It
would then become categorized as a gram–negative stain (Case, Funke, & Tortora). A gram–
negative bacteria has a cell wall made of a thin layer of peptidoglycan and a thick layer of
lipopolysaccharides thus holding onto the red dye (Case, Funke, & Tortora). Bacteria have different
shapes and these shapes determine what family they belong in. There are

Lab Report
Purpose: is to determine the unknown bacteria with a variety of biochemical tests.
There are many reasons that contribute to why it is so important to test patients for both high and
low risks diseases. The most important reason would be to know the identity of microorganism and
how it can be treated .This study was performed in microbiology laboratory class by applying the
microorganism to the tests that have been performed in the class prior to the identification of the
unknown.
First, the lab professor handed out a bacteria that was on the unknown streak plate labeled B5 that
consisted of an unknown gram positive or gram negative bacteria. A sterile technique was performed
by the lab manual instructions which is stated in the references. ... Show more content on
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The Methyl Red test alone indicates if the bacteria can perform a mixed– acid fermentation because
some bacteria can produce enough stable acid end products to overcome the buffering system and
lower the pH (Leboffe & Pierce, Methyl Red and Voges Proskauer (MRVP) Broth, 1996, p. 55). The
MR test is done by adding three drops of methyl red solution and immediately a copper color or
which indicates it was negative and does not have a mixed– acid fermentation or turns red for
positive mixed fermentation. Next is the Voges Proskauer test (VP) which indicates if the bacteria
further metabolize the acids to less acidic products such as acetonin and 2, 3 butanediol . This
substances are always found together because they are indicators of one another. The VP reagents A
and B are added and then mixed to see if the bacteria can oxidize the substance acetonin to diacetyl.
If this substance further reacts to the bacteria then a red color will form at the top which will make
the test positive if it stays a copper color then the test is negative. This test takes the longest because
the process it has to go through. This test is recorded every ten minutes to see if there was any
change up to an hour. The next test that was perform was the Phenol Red broth test for both
carbohydrates glucose and lactose. Each of the test has a red pH indicator to determine if the
fermentation end products and its ability to enzymatically convert the

Unknown Lab Report
Unknown Lab Report
Unknown Organism #6
Ann Le (Phuoc)
May 6, 2010
Dr. Carrington
Microbiology Lab– MW 12:50
Le 1
I. Introduction
My unknown organism #6 is Morganella morganii, which is a gram–negative bacillus rods
commonly found in the environment and also in the intestinal tracts of humans, mammals, and
reptiles as a normal flora. (3, 5) This bacterium Morganella morganii, was first discovered in the
1906 by a British bacteriologist named H. de R. Morgan. (2) Despite its wide distribution, it is an
uncommon cause of community–acquired infection and is most often encountered inpostoperative
and other nosocomial settings. (2, 3) Morganella morganii infections respond well to appropriate
antibiotic therapy; however, its ... Show more content on Helpwriting.net ...
Next I performed a KOH test to further confirm that my organism was a Gram–negative species. For
the KOH test, I added 3 drops of 10% potassium hydroxide (KOH) to a small drop of distilled water
onto a clean microscope slide, transferred a visible clump of organism to the KOH solution using
my inoculating loop. I than mixed the cells into the solution using small, circular motions for 60
seconds and then lifted up the loop to look for what appears to be a "stringing" affect which means
it's confirmed that it is gram– negative species. Next, I created a streak plate using nutrient agar so
that I could see pure culture of my organism. I aseptically obtained a loop full of my organism and
gently inoculated one quarter of the nutrient agar plate by running the loop back and forth across the
surface. I then flame sterilized the inoculating loop, allowing it to cool for 10 seconds, and then
streaked the organism from quadrant I into quadrant II using a zigzag motion technique. I repeated
those steps streaking from quadrant II to quadrant III and then streaking from quadrant III to
quadrant IV. Once completed, I put the streak plate in the incubator at 37° for 24–48 hours. 48 hours
later, I check my streak plate and it had a lot of growth on it. I was able to determine that the
organism was definitely an off white color, opaque. The IV quadrant was the quadrant that best
Le 5 represented the colony. The whole colony was round, having

Gram Staining
In the medical field, certain bacteria need specific antibiotic treatments and to find out what class
the bacteria belongs to (whether if it is gram negative or positive) the specimen would have to
undergo differential (Gram) staining. Hans Christian Gram was the Danish bacteriologist behind the
gram staining technique. His Gram stain technique led to the discovery that Typhus bacillus did not
retain the stain. Another procedure like differential staining is called simple staining. The main
difference with this procedure is its simplicity and use of just one dye while the differential staining
is more complex, uses more staining and helps shows cellular components of the bacteria. There are
3 bacteria that will be in use for the Gram staining. ... Show more content on Helpwriting.net ...
Their cell walls usually contain mycolic acid which does not stain well with conventional staining
methods. So, for acid fast staining dyes that react strongly to the mycolic acid are used like the
Carbolfuchsin. Carla Lamanna described Carbolfuchsin as, "a mixture including phenol, water, and
a dye (basic fucshin) much less soluble in water than in phenol" (Lamanna, 1946). This part of the
lab is very important because certain bacteria families like mycobacteria have that mycolic cell
walls and can cause serious illness. Also, bacteria from the mycobacteria family require certain type
of antibiotics and a specific dosage to combat it. Staining in general has been the backbone of
fighting against infectious bacteria. Acid fast staining is also referred to as Ziehl–Neelsen stain.
They are the founder of the acid stain and are German doctors. They are Friedrich Neelsen and
Franz Ziehl. The lab we are doing, with regards to the acid–fast staining, is in similarity with the
experiment these doctors did to identify acid fast organisms. The Mycobacterium in this experiment
is expected to have a pinkish reddish stain while having a rod type

Essay Aseptic Technique and Bacterial Anatomy and Morphology
Lab, Week ASEPTIC TECHNIQUE AND BACTERIAL ANATOMY AND MORPHOLOGY
Introduction Part I: Aseptic Technique The purpose of this experiment is to become familiar with the
specific microbiological technique known as the aseptic technique, which is used to avoid
contaminating cultures. In this case a pure culture of an unknown organism was introduced to a
sterile medium of Phenol Red Glucose Broth Durham. The culture was obtained from a 52–year old
male truck driver who is complaining to his doctor about pain in his lower abdominal and back.
With a family history of prostate cancer, he worried that his sudden need to urinate during the night
and infrequent appearance of blood in his urine might be bad signs. An ultrasound ... Show more
Observe and notice the color and content of the test tube. Place the phenol red tube into the 37
degree incubator by click and dragging it to the incubator. Click new day. Right click on incubator
and select prgb to retrieve the phenol red test tube. Observe the test tube and record results. Drag the
test tube to the biohazard bag and discard. To perform the sterile transfer technique, obtain another
tube of phenol red glucose broth medium and label the tube as prgb #2. As you are performing the
next few steps, in order to ensure that you are successfully flaming the lab equipment and sterilizing
them properly, observe the information that appears at the bottom of the lab which notifies you if it
has been flame properly and/or is sterile. Select the inoculating loop from the tool dropdown menu.
Right click on the Bunsen burner and select on to ignite the burner. Flame the loop to sterilize it,
when removed from the burner and it is sterile it appears red. Remove the caps from the test tubes,
by right clicking and selecting remove caps, and quickly drag them over to the burner to flame their
mouths. Perform the aseptic transfer by dipping the loop into the culture from the test tube on the
left and transferring it to the sterile medium on the right. Drag the test tubes and flame their mouths
once again and then replace cap immediately. Flame your loop. Place the inoculated culture into the
37 degree incubator. Right click

Tube # 11 Lab Report
Title:
The identification of two unknown bacteria species in tube # 11.
Introduction:
What is the identity of the two unknown species in tube #11? Pure cultures are needed to identify
the two types of bacteria. Techniques such as the streak plate method can help isolate the two
different types of bacteria growing. Characteristics such as color and morphology of the bacteria
colony are ways microbiologist can separate the bacteria.2 The ten possible bacteria species in tube
#11 are Bacillus subtilis, Clostridium sporogenes, Escherichia coli, Pseudomonas fragi, Serratia
marcescens, Alcaligenes faecalis, Staphylococcus epidermidis, Sarcina lutea, Micrococcus luteus,
and Micrococcus roseus. To identify the bacteria species possible stains that ... Show more content
on Helpwriting.net ...
Run this test twice once for species A and then species B using the pure culture slants. Inoculate the
litmus milk with bacteria by placing the sterile loop in the slant touching the bacteria growth. Then,
place the loop with bacteria on it into litmus milk tube and go all the way to the bottom of the tube.
Then incubate the litmus milk tube at 37C for species A and 25C for species B. The results for a
litmus milk test are litmus reduction, acid production, base production, and neutral. 1
The third test is the Cytochrome oxidase test. This test is for the gram negative bacteria only;
unknown species A. Using a plastic inoculating loop pick up the gram negative bacteria and smear it
onto an oxidase Drislide. If the spot on the paper turns purple within 20 seconds, the test is positive.
If the spot on the paper does not change color, the test is negative.1
Lastly is the Amylase test. This test is for only gram positive bacteria; unknown species B. Using a
starch agar plate inoculate gram positive bacteria onto it. Make any kind of design on the starch
agar. Label the plate starch agar and unknown species B. Incubate the starch agar for at least 48
hours at the 25C. After incubation open the agar plate and cover the entire surface with iodine and
allow it to soak into the agar for 5 to 10 minutes. If there is a clear zone around the growth pattern or
halo this means, there is no starch present and the bacteria have consumed the starch. Having a clear
zone or halo means the test is

Gram Staining Paper
Background:
Bacteria is a single celled prokaryote microorganisms, rapid mutations causes bacteria can be found
just about anywhere.Gram staining helps to classify two groups of bacteria, Gram–positive and
Gram–negative. Gram–positive bacteria's cell wall has a stronger attraction for crystal violet,
because of more peptidoglycan. Gram–negative is a group of bacteria that doesn't retain the crystal
violet stain used in the Gram staining method, making positive identification possible. These are the
many characteristics used to describe the morphology of a bacterial colony; size, shape, color,
texture, height, and edge. Bacteria can be prokaryotic organisms, they lack a nucleus and
membrane–bound organelles. Most are unicellular, but some species live ... Show more content on
Helpwriting.net ...
Use sterile cotton swabs, and swab any surface in classroom.
Touch your finger gently to this circle and then clean your finger with an alcohol pad and touch it to
this sector.
Draw each plate, showing how colonies are spread across the agar surface. Pick several colonies on
your plates and describe them using the terms above.
Place petri dish in incubator and wait.
Place a drop of water on a clean slide.
Heat the inoculating loop until it glows red. Let it cool then remove a small amount of culture from
the agar surface; touch it several times to the drop of water until it just turns cloudy.
Burn the bacteria from the loop and allow the loop to cool, use the loop to spread the suspension
over the surface of the slide to form a thin film.
Allow suspension to air dry.
Hold the slide with a clothespin and then heat fix the bacteria on the slide by passing it over the
flame 3–4 times. Do not overheat the slide, it should feel warm but not

Life is full of bacteria that can be beneficial and harmful at the same time. They are the smallest
living things that can be found everywhere in the air, soil, water, and even in our body. We actually
share our body with many bacteria. Therefore, without the good bacteria we could die because the
good bacteria can help digest the food we eat and protects us from bad bacteria that make us sick.
On the other hand, living with those organism can be harmful and can cause many diseases. Some of
these diseases are produced when bacteria attack the tissues in a plant or animal. Also, it can attack
organisms by releasing chemicals. Therefore, they can cause damage to a persons body. These
pathogenic organisms are able to reproduce rapidly and split into two identical copies of themselves.
... Show more content on Helpwriting.net ...
The results that I observed by Gram Staining was Gram Negative rod (bacillus). Then, I performed a
Negative Stain in order to further more validate that I had bacillus, since Negative Staining would
provide an accurate determination of the shape of the microbe by staining the background of the
microbe. In observation of my unknown using Negative Staining; I knew that I had a microbe with
bacillus.
Day#2:
I did a Fermentation Test where I inoculated 1 tube of phenol red sucrose, 1 tube of phenol red
glucose, and 1 tube of phenol red lactose. A positive result for fermentation would be a change of
the color (original color is a red color to a yellow color) of the sucrose, lactose and glucose as well
as if gas was produced, gas bubble present within the Durman tube inside the test tube.
All 3 of my test tubes came out positive, all 3 had the color change, as well as the presence of the
gas bubbles within the tubes of the test tubes. Then, I prepared a streak plate and it was incubated at
37˚C. When I returned days later to view my results; I observed that white colonies had

How Gram Staining Is Negative Or Positive, It 's...
Purpose:
The purpose of this lab was to be able to gram stain given cultures and examine their reaction to
certain dyes and determine whether the culture is negative or positive, it's morphology, and
arrangement of the cells. By using the Gram staining method, microorganisms can be narrowed
down for the identification process as well as the leading to diagnosis
Procedure:
For this experiment, we were given three gram staining slides as well as a petri dish with five
different types of incubated microorganisms that were divided. The five different organisms on the
petri dish being observed were Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa,
Klebsiella pneumonia, and yeast known as Candida albicans. On the surface of the ... Show more
On the third slide, the smear was not taken from the petri dish, however it was taken from a
thorough swab of the mouth and smeared within the given margins on the slide. The samples were
then left to air dry. Once the slides dried, they were passed through a flame 4–5 times to follow the
aseptic technique protocols.
Once this was done, our next step was to begin the Gram staining process. First, is the Primary stain,
using the crystal violet dye color. The slides were all laid out on top of a rack placed over the sink
station and were flooded with the violet dye color; the slides were left with the dye on them for 1–2
minutes to assure they were stained. The slides were then rinsed off thoroughly. Next, the slides
were stained with the Mordant (fixative) Iodine Gram stain which appears brown in color. The slides
were then flooded with the brown dye for 1–2 minutes and then rinsed off.
After all the slides were stained accordingly, they needed to be decolorized with 95% ethyl alcohol
which is clear in color, and will be the determining factor between whether the stains are negative or
positive. Just as we did with the crystal violet dye and the brown iodine dye, the slides were
drowned with the 95% ethyl alcohol. The difference here was how long to leave the alcohol on each
depending on how thick the samples were. The slides labeled "mouth" were removed within 20
seconds. The rest of the samples were removed within the following 10 seconds.
Lastly, to complete

My Unknown Colonies
Unknown #3 Report To start off unknown #3, I picked out O17 from rack A and wrote down my
name, date, class, and I first noticed the broth was a light yellow that was quite cloudy or milky.
Soon later I streaked my organism onto a TSA plate and incubated it at 37oC for 24 hours, t was
almost a perfect plate. There was no contamination; I could tell it there was only one species on the
plate and that it was okay for me to move on. There were many isolated colonies in quadrants 3 and
4. The colonies were small and white in color, it was not translucent. I then began to make my 2
slants, inoculating a straight line on each slant, I incubated it at 37oC for 24 hours. The next day, I
made sure my slants were pure and also there was a thick line of organism where I had inoculated
with a yellow–white color. Now I was ready to begin making my slides and start staining. I used E.
Coli and S. Aureus next to my unknown to help me ... Show more content on Helpwriting.net ...
When checking the results, H2S was negative, there were no black precipitants in the tube, and the
organism was motile. After recording those results, I went to the hood to add Kovoc's reagent to the
SIMs and waited for about 30 minutes before observing to get the results, and it came out to be
negative for indole as well. At this point, only one organism matched every result that I received
during all my tests, I decided to do my confirmation test. I did Methyl Red and Voges–Proskauer
tests for my confirmation test. After inoculating the MRVP broth and incubating it at 37oC for 120
hours, I took my separated samples to the hood and added in the Methyl Red in one tube and reagent
A then B in the other tube, I mixed it and checked in on both tubes after every 10 minutes. About 45
minutes later it was clear what the results were, negative for methyl red and positive for Voges–
Proskauer. That confirmed that my unknown O17 was Enterobacter

Gram Staining Research Paper
Bacteria cells are examples of prokaryotes (simple cells). They have no nucleus thus, their DNA are
clumped in an area without a nucleus or membrane. Although prokaryotes do not have organelles
such as Chloroplasts, mitochondria or nuclei, bacteria cells still have ribosomes (Radar, Andrew).
Bacteria reproduce and duplicate by the process of binary fission. Binary fission is the processes in
which a single cell divides into two identical daughter cells each with identical DNA to the parent
cell.
Gram staining, also known as Gram's method, is the most important and universally used staining
technique in the microbiology and bacteriology laboratory. It is almost always the first test
performed in the identification of bacteria (Xu, George).The ... Show more content on
Helpwriting.net ...
These two types of bacteria have distinct and consistant differences in their cell wall constituents
(Rollins, D.M). Gram positive bacteria stain violet under a microscope due to the presence of a thick
layered wall of peptidoglycan. These bacteria dye violet do to the that fact that the thick
peptidoglycan walls retain the crystal violet. While gram negative bacteria appear red/pink due to
only a thin layered wall of peptidoglycan which does not retain the crystal violet during the
recolouring process with alcohol, usually, acetone or ethyl (Bruckner, Monica).
There are three main types of bacteria.They can be determined and distinguished by their cell
morphology. Cell morphology is the identification of the shape, structure, size of the cell and its
form. It pertains to the shape of bacteria. For instance, Coccus (cocci) bacterium are spherical and
generally round shaped. Bacillus bacterium are generally rod shaped and are a genus of gram
positive bacteria. Finally, the third common type of bacterial morphology is the spirillum bacteria.
Spirillum bacteria s generally a spiral shaped bacterium and are a genus of the Gram

Unknown Lab Report Sample
Title: Identification of Unknown Bacteria
Purpose: The purpose behind this unknown project is to help us determine the identity of the liquid
culture we have selected. With the freedom we've been granted, we are permitted to use any of the
tests that we have performed in our previous labs to assist us with identifying the organism. This
project is intended to push us to use the knowledge we have acquired, using proper staining
techniques and thorough understanding of testing techniques and results to draw conclusions.
Conclusion: The first two tests performed required that I streak the liquid culture onto a TSA plate in
order to isolate individual colonies. The second involved performing a successful gram stain, which
resulted in gram positive staphylococci. After successfully performing these tests I was able to
narrow down ... Show more content on Helpwriting.net ...
pneumoniae) leaving me with Sa, Se, Ef, P.pyo, and Ml. Following my dichotomous key, the next
test I decided to perform was a catalase test in order to determine if the enzyme catalase is produced
by the bacteria. The sample of the bacteria I took did bubble, this indicates that the bacteria does
produce the catalase enzyme as well as requiring oxygen to respire. Based on the results of the
catalase test there were three possible microbes I could have Ml, Sa, and Se. For my next test I
decided to use an MSA plate to determine if my unknown microbe could or could not grow in the
presence of the mannitol salt, along with testing to see if it would or would not be able to ferment
the mannitol salt. After allowing the bacteria to grow, I noted that the plate remained the same
pinkish color it originally was however, I did several white colonies growing on the plate. The pink
color that remained shows that the organism is unable to ferment the mannitol salt thus the acidic
byproduct that turns the medium yellow will not be produced. Therefore the organism cannot be Sa
since that

Escherichia And Gram Staining
Most bacteria are classified as either gram positive or gram negative. Gram positive is a purple stain
and gram negative will appear pink or red. Gram negative can cause many kinds of infections. One
type of bacteria is Escherichia which is a rod shaped bacteria. A Gram stain is used in lab setting to
identify what type of bacteria is present. A sample is placed in a nutrient media and incubated. This
media will encourage bacteria growth present. This process allows for further testing and to identify
what kind of bacteria is present to allow for appropriate treatment.
Bacillus are rod shaped, prokaryotic cells, they form spores (gram positive and gram negative) on
gram staining. Escherichia are rod shaped, prokaryotic cells, however they

Treatment Of A Sexually Transmitted Disease
An 18–year old female has been diagnosed as having a sexually transmitted disease due to Neisseria
gonorrhoea; Gonorrhoea is a sexually transmitted infection (STI) caused by bacteria called Neisseria
gonorrhoeae or gonococcus. Gonorrhoea is pathogenic bacterial type of infection.Itis a rather
common infectious bacterium that can grow and rapidly multiply in the mucous membranes, in
areas such as the mouth, throat and anus of males as well as females. Cervix, fallopian tubes and the
uterus of the female reproductive tract are also to be infected. An estimated of 650,000 people are
affected by gonorrhoea per year.
The bacteria are mainly found in discharge from the penis and vaginal fluid from infected men and
women and can be passed through ... Show more content on Helpwriting.net ...
Both sexes experience sore throat in oral infections if they are not asymptomatic. However, this
response is most commonly mistaken as a viral sore throat.
Describing the clinical presentation of this infection& health and safety issues when diagnosing the
infection in the microbiology laboratory
The recommended method for testing for gonorrhoea is nucleic acid amplification test (NAAT).
NAAT is a molecular test designed to detect the DNA (genetic material) of Neisseria gonorrhoea.
This tests is also more specific than other gonorrhoea tests
A sample of cells will be diagnosed by your doctor to determine the presence of gonorrhoea in your
body. Samples can either be collected by urine tests (helps with identification of bacteria in the
urethra), also a swab from the affected area (which removes the need for pelvic exam for women). A
swab of your urethra, throat, rectum or vagina may collect bacteria that can be identified in a
laboratory.
The collecting of a sample from the urethra, the anus, the cervix or the rectum may cause mild
discomfort or pain. A minority of women feel slight cramping while the speculum is inside the
vagina. Collecting of urine sample usually does not cause discomfort.
Having a sample of fluid collected from the cervix, the urethra, the anus, the eye or the throat
causes/is at very little risk. Women may experience a small amount of bleeding from the vagina if a
sample

Gram Staining
Title
Elizabeth Huynh
November 16, 2014
Jason Atkins
Unknown #7
Purpose
The purpose of this study was to identify the
There are a group of tests used specifically to differentiate bacteria in the Enterobacteriaceae family.
These
Results
Table 1 Microscopic Data of Differential Gram Stain
Gram Stain (A) Gram–negative Cell Results (B) Gram–positive Cell Results
Before Staining Transparent Color Transparent Color
After Crystal Violet Stain Purple Color Purple Color
After Iodine Stain Purple Color Purple Color
After Decolorization with Alcohol Transparent Color Purple Color
After Safranin Stain Pink/Red Color Purple Color
Table 2 Physiological Tests Conducted to Identify Shigella flexneri
Biochemical Tests Results Symbol
Phenol ... Show more content on Helpwriting.net ...
The Bacteria A cells that were pink/red in color after the addition of the Safranin stain were the
Gram–negative cells. Gram–negative cells have higher lipid content in their walls; therefore they
lose the primary stain color after the decolorization step. After the Gram–negative cells were
counterstained with Safranin, they turned pink or red, whereas Gram–positive cells remained purple.
After the isolation of the Gram–negative bacteria, a variety of tests were performed to identify the
unknown bacterium as Shigella flexneri. Of the three Phenol Red broth tests, the PR Glucose broth
test was the only one whose results were positive as indicated by the change in broth color from red
to yellow and by the presence of bubbles in the tube. These results indicate that the bacterium was
able to ferment glucose with acid and gas end products. The bacterium was unable to ferment
sucrose or lactose as the broth in both tubes remained red and no bubbles were present. Just from the
Phenol Red broth results, the unknown bacterium could either be Salmonella typhimurium or

Shigella flexneri. The results from the Methyl Red and Voges–Proskauer tests show that the
bacterium was able to perform mixed acid fermentation but could not ferment glucose where its acid
products would quickly convert into 2,3–butanediol and

The result of this experiment was prevented growth of any microorganism in nutrient agar out of
aseptic technique and that what we expected and we achieved to our goal of this lab. Another section
of this lab, we using another technique known gram staining. Gram staining is a common technique
used to differentiate two large groups of bacteria based on their different cell wall constituents4.
This technique helps to identify among Gram positive and Gram negative groups by coloring these
cells pink or violet. Gram positive bacteria stain violet due to the presence of a thick layer of
peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with.
Alternatively, Gram negative bacteria stain pink or red, which is attributed to ... Show more content
on Helpwriting.net ...
In this lab, we sued Sterile toothpicks, a gram positive bacterial sample growing in nutrient broth
(Staphylococcus aureus), a gram negative bacterial sample growing in nutrient broth (E. Coli), Gram
Stain sets, glass slides, Light Microscopes with immersion oil. The first stride was Resuspended the
culture tubes by tapping, then, making a (triple slide) on a glass slid. The triple sild was divided a
slide to three section, place a drop small loopful of Staphylococcus aureus on one end in the slid,
then, place drop of small loopful of the E. coli in the other end, after that, added a drop mix among
Staphylococcus aureus and E. coli in the center of slide. After completely dry slid, it should start the
Gram–Staining Protocol. the Gram–Staining Protocol was used four types of stains those are Crystal
violet, Iodine, decolorize, and safranin, each of stain was stayed about 60S and the rinsed with
water. Finally, drying the slide by pressing the slid among the pages of the Bibulous table and put
the slide under the

Soil vs Microbiology
TITLE
Lab #4 Soil –vs– Water Microbiology
INTRODUCTION
There are 4 learning goals for this lab:
1. Collect samples and compile data from at least 2 sources (soil; water) of your choice.
2. Identify at least 2 Prokaryotes (bacteria) and 2 Eukaryotes (fungus) in your samples.
3. Research the importance of bacteria and fungus to Earth in a non–medical context.
4. Compile a high–quality, 3+ resource (excluding the lab worksheet), MLA–cited in–text laboratory
report using the scientific method by class due date.
HYPOTHESIS
The purpose of this lab is to:
1. Collect a sample of soil from (your school) on October 27th 2011 and collect a sample of pond
water from (the name of your lake or pond) on October 27th and record the data ... Show more
Microbiology Introduction. 10th Ed.). It was no surprise to me that E–coli were found in the soil
sample because of the geese and E–coli comes from fecal matter of animals. The soil we retrieved
was from the area by the lake and therefore very possible to get a positive result for E–coli. All of
the fungi and bacteria found from the environment share a symbiosis relationship, two organisms
living together in a close association that is beneficial to one or both of them. (Tortora, Funke, and
Case. Microbiology Introduction. 10th Ed.) The relationship that bacteria and fungi share with each
other contributes to the biogeochemical cycle and without bacteria and fungi we could not continue
our existence on our planet "earth.
METHODS AND MATERIALS MATERIALS 1 Becker 1 Nutrient agar plate 1 pair plastic gloves 1
Potato agar plate 1 Staining tray 100ml of distilled water 2 MacConkey Agar Plates 3 Blank slides 3
plastic cups 6 pipettes 95% Grams alcohol Bibulous paper Boat & Scale Bunsen Burner & Flint
Crystal–violet Grams Iodine Incubator of 35⁰ Celsius (silver) Inoculating loop Microscope Pond
water Safranin Soil Tap water Timer Tweezers METHODS Methods performed as per BIO 270 Soil
sample on October 27th 2011 at 11:45 a.m. Water sample on October

Introduction: Background: This lab report will discuss the identification of an unknown microbial
organism by utilizing Bergey's Manual , the scientific method as well as the necessary laboratory
experiments prescribed by the dichotomous key for the specific bacteria type that is determined.
Purpose: To utilize Bergey's Manual along with other prescribed processes in order to satisfactorily
grow, collect data on and successfully identify an unknown given culture. Materials and Methods:
1. Gram Staining: In order to determine the type of bacteria on hand by using the dichotomous key
within the laboratory manual the first test to be utilized would consider whether the microbe
presented is gram positive or gram negative. In order to perform a gram stain you must utilize the
steps listed in figure 7.1 of the laboratory manual as well as the four basic steps. These steps are:
applying the primary stain (crystal violet), applying the mordant (gram's iodine), utilizing a
decolorizing agent (ethanol) and finally applying the secondary stain (safranin). When the process is
completed, look at the slide(s) under the microscope. If the microbe is pink it is ... Show more
The gram staining when viewed appeared to be gram negative in nature while presenting a bacillus
(rod) shape. When grown on the streak plate the culture seemed to be flat in elevation, entire within
its' margin, circular in appearance and pinkish/ red in color. The agar slant utilized displayed an
entire growth pattern while also seeming pinkish in color. The oxidase testing showed to be
negative, the culture never turned blue or black the pigment presented by the colonies appeared to
stay red at 25 degrees C. Therefore, based on the results and data obtained within the experiments
prescribed, I have determined that my unknown microbe, #80, is Serratia

Chemical Chemicals : A Study And Their Manufacturing...
All chemicals used in this study are of analytical grade, Table 3.1 shows the chemicals used in the
study and their manufacturing companies.
Table 3.1 Chemicals used in the present study.
Chemicals Manufacturing companies
Sodium acetate Sigma, USA
Yeast extract Lab M, UK
Agar B & V srl–Parma, Italy
Acetic acid ADWIC, Egypt
Glucose Sigma, USA
GABA Loba, India
MSG Sigma, USA
DEAE–Cellulose Sigma, USA
Catalase enzyme Biodiagnostic, Egypt
APTT kit & PT kit Biomed diagnostics, Germany n–butanol Sigma, USA
Glycerol Acros, USA
Ethanol El NASR Pharmaceutical chemicals, Egypt
Protenase K enzyme Sigma, USA α–chymotrypsin Amoun Pharmaceutical co, Egypt
Catalase enzyme Biodiagnostic, Egypt
Gram staining kit Axiom, Egypt
H2O2 El NASR Pharmaceutical chemicals, Egypt
Bile salts SAS chemicals, India
Nutrient broth Oxoid, England
Tryptic soy medium Oxoid, England
MRS medium Lab M, UK
3.2. Samples collection
A total of seven marine sediment samples were collected from the Red Sea, Egypt (Ras Gharib,
Marina, El Tor, Nwebaa, Dahab, Ras Sedr and Naama Bay) and seven shrimp specimens were
collected from the Red Sea, Egypt.
The samples were collected in sterile containers and kept in ice box until delivery to the laboratory.
Once delivered to the laboratory, the samples were processed for isolation.
3.3. Media
The following media were sterilized by autoclaving at 121ºC for 20 min and initial pH was adjusted
before sterilization using 1N NaOH or 1N HCl.
De Man, Rogosa and Sharpe (MRS)

Ames Test Lab Report
The Ames test is an initial screening assay that can be used to determine the likelihood that the
chemical being tested will be mutagenic. This test works by using different strains of the bacterium
Salmonella typhimurium that are carrying a mutant gene making it incapable of producing the
amino acid histidine from the ingredients in the culture medium. These mutations have the ability to
be reversed and restore the functional sequence to the gene; which will allow the bacteria to
synthesize histidine. The mutated bacteria also known as revertants will then grow on the media
lacking histidine.
A strain of Salmonella typhimurium that is histidine negative is inoculated on a culture plate
containing growth medium lacking histidine. Since this strain of Salmonella typhimurium requires
histidine for growth, it will not grow on culture plate. This will be considered the control plate. Rat
liver extract is added to another strain of Salmonella typhimurium that is histidine negative. The rat
liver extract is important because some chemicals that are classified as pro–mutagens require
metabolic activation in order to be considered mutagenic. The liver enzymes are responsible for the
activation of pro–mutagens into mutagens. This mixture is inoculated onto a second culture plate
with growth medium also lacking histidine. A well is then placed in the culture plate and the ...
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The next step involves incubating the culture medium for 48 hours at 37° Celsius. If the chemical
being tested is

The Center for Disease Control has conducted this experiment in order to learn more about the
characteristics of Bacteria F, a potentially lethal disease that can decimate humanity. Learning more
about Bacteria F is essential due to its potential to be dangerous and the huge diversity among
bacteria. Bacteria are also very diverse in size and arrangement; for example, Bacteria have the
potential to be round (cocci), rod (bacilli), or spiral shaped. Gram–staining is a technique that can
help the scientist learn more about the bacteria. Gram–staining was a technique developed by H.C.
Gram in 1884. Gram–staining is intended to categorize bacteria by their composition regarding cell
wall composition, cell wall layering, bacteria size, and more. ... Show more content on
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Gram–negative bacteria are generally thinner but have an outer membrane, whereas Gram–positive
bacteria do not have the outer membrane and are larger. The outer membrane aids in processes like
diffusion and osmosis and also affects the permeability of the bacteria. Generally, thicker outer
membranes lead to less permeability but more protection for the bacterium. On top of that, Gram–
positive bacteria exhibit multiple Peptidoglycan layers as opposed to Gram–negative bacteria's
single layer. Peptidoglycan is a polymer that strengthens the cell wall due to its rigid state. The
Peptidoglycan impacts the cell wall of the bacterium; a Gram–positive bacteria's cell wall is usually
thicker than a Gram–negative bacteria due to the Peptidoglycan concentration, but Gram–stain–
negative bacteria tend to have a two–layered cell wall and Gram–positive bacteria only have a single
cell wall layer. Unfortunately, Gram stains are not always completely effective; in some bacteria, the
Gram–stain is completely ineffective or displays that half the cells are positive and half the cells are
negative. In such a case, a Gram–stain is not enough to determine the characteristics of that

How Important Is There A Gram Staining Procedure?
There are numerous reasons why it is essential that gram stain and microscopic examinations are the
first step in identifying pathogenic bacteria. Gram stains are an important procedure because it can
determine the stain of the cell wall of bacteria sample. It also allows laboratory technicians to
classify the bacteria in to either gram positive or negative as well as allowing them to analyse and
study the morphology and arrangement of bacteria. Whilst determining the bacteria type and type of
gram stain, the test also allows the doctors to prescribe the correct medication and dose and proceed
with the correct diagnoses and treatments to eliminate the bacteria present. The gram stain procedure
is known to be a very rapid procedure which has many benefits such as quick treatment and
stopping the bacteria from spreading in many ways which may be in the environment or inside the
human body. This procedure which allows professionals to determine the bacteria is also an
inexpensive technique which benefits many individuals as it is affordable. ... Show more content on
Helpwriting.net ...
It also allows making diagnoses in many cases as bacteria cannot be seen with a naked eye;
therefore a microscope is needed for evaluation of bacteria groups.
Many other tests can be used to identify bacteria and they are used when it is best suited as there are
many disadvantages in comparison to the gram stain procedure which is a quick procedure and it is
not expensive to proceed

Gram Staining Essay
Introduction
This report discusses the technique of Gram Staining in order to characterize bacteria. Gram–
staining is a process in which the cells are immersed in crystal violet, iodine, ethanol, and safranin.
Based on bacteria's cell wall, most common bacteria are either Gram–positive or Gram–negative.
The Gram–positive cell wall are composed of multiple layers of peptidoglycan layers, whereas the
Gram–negative cell wall has one layer of peptidoglycan. Through the technique of Gram–staining,
the Gram–positive cells will turn purple do to the cells multiple layers of peptidoglycan.
Materials and Methods
The area being used underwent an aseptic technique to ensure the culture would not be
contaminated. The surface being used was wiped with alcohol and the lab member's hands were
washed. All non–flammable instruments were flamed. Two slides were then sterilized by wetting the
slide and then drying it.
Before preparing the Gram–staining, the technique of making a bacterial slide with heat fixation was
practiced. On one slide, a small drop of water was placed. Using a sterile inoculating loop, cell
material from a slant stock cultural was placed into the water droplet and mixed. The slide was then
left to air dry. Once the slide was dry, the slide was picked up by a non–flammable tong and ... Show
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A drop of water was added to two slides, cleaned using the aseptic technique, by an inoculated loop.
The inoculated loop was sterilized, by placing the loop over the gas flame, and then placed into a
test tube containing Escherichia coli. The Gram–negative was then transferred to the drop of water
on one of the slides. The same method was used with Gram–positive Staphylococcus epidermidis,
transferring the cell material to the other drop of water. The two slides were then left to air dry.
Then, each slide was passed through the cool part of the gas flame three times as previously

Alpha Haemolysis Lab Report
Introduction
There are many reasons for knowing the identity of different microbes when presented with them.
The reasons include identifying the causative agent behind the disease in a patient, understanding
how it can be treated, as well as knowing the microbe that should be used for making the right
antibiotics. With this being said, their correct identification is not only significant in a microbiology
lab but also in the medical, manufacturing, and pharmaceutical fields. The first test used in the
identification of unknown bacteria numbers 3 and 4 was the Gram stain, which was used to
differentiate between gram–positive and gram–negative bacteria based on their different cell wall
elements. The Gram stain procedure distinguishes between ... Show more content on
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Such bacteria require an enriched environment as compared to bacteria that grow more easily. It is
also used to differentiate hemolytic bacteria, particularly Streptococcus species, also making it a
differential media in distinguishing the destruction of red blood cells caused by cytolytic toxins
secreted by select bacteria. If the bacteria were to have Beta hemolysis, there would be a large area
of clearing around the bacteria colony on the BAP. When Alpha hemolysis occurs, there is a blue–
green tint on the bottom of the plate, as if it were bruised. With gamma hemolysis, there is actually
no hemolysis, therefore no change in the agar would occur. A Hektoen Enteric Agar was used next
which is both a selective and differential medium intended to separate and distinguish members of
the Salmonella and Shigella species from other Enterobacteria. Bile salts and bromthymol blue and
acid fuchsin dyes hinder the growth of most Gram–positive organisms. Lactose, sucrose, and salicin
are fermentable carbohydrates in the HE agar that encourage this variation in growth and color.
Ferric ammonium citrate that is in the agar allows the observer to see hydrogen sulfide creation by
reacting with hydrogen sulfide gas to make a

Gram-Negative Staining Lab Report
Tiffany O'Connor
9/2017
Gram–positive and Gram–negative stain
Purpose: Staining is done to differentiate between two varieties of bacteria, gram–positive and gram
negative.
Theory and Background: Gram–positive and Gram–negative represents whether a cell wall retains
the primary dye color in the staining process after decolorization. The difference in the structure of
the cell wall determine if this happens.
In Gram–positive cells the walls are much thicker than Gram–negative. Gram–positive cell walls
consist of several layers of peptidoglycan and groups of molecules called teichoic acids. The
teichoic acids line up perpendicular to the many layers of peptidoglycan. Gram–negative cells walls
have only one layer of peptidoglycan surrounded by an outer membrane. The outer membrane has
porins, or proteins that act like pores and allow the diffusion of molecules. The outer membrane also
has lipopolysaccharide or endotoxin, This helps maintain the integrity of the wall, it is also a toxin
but only released when the cell disintegrates.
Gram–positive cell wall: Gram–Negative cell wall:
http://textbookofbacteriology.net/structure_5.html=positive ... Show more content on
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The key to the process is in the second step, this is when iodine is applied to the specimen. The
iodine causes the dye to form crystals that get trapped in the cell walls. In Gram–positive cells the
walls are thicker and the layer of dye saturates the cell wall more extensively. The third step in the
process is to apply alcohol which dissolves the lipids in the outer membrane of the Gram–negative
cells. This allows for the violet dye to wash out, leaving these cells colorless. Step four is to add a
counterstain. In this case it was safranin. This is done so the Gram–negative cells will be seen in a
different

Gram Staining Bacteria

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