Bacteria Classification By Gram Staining Essay

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
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Microbial Survey, Smear Preparation, and Simple Stain Essay
MICROBIAL SURVEY, SMEAR PREPARATION, AND SIMPLE STAIN
Instructional Objectives 1. Define
Roccal = green, liquid disinfectant.
Pathogen = an agent which causes disease.
Wet Mount Slide = a microscope slide of a liquid specimen covered with a cover glass.
Yeast = a single celled fungi.
Budding = a true characteristic method of asexual reproduction among yeasts where budding of a
new cell from a parent cell can be observed.
Mold = multicellular masses of filamentous fungal growth.
Hyphae = individual filaments of mold, generally comprised of more than one cell.
Mycelium = the entire mass of the intermeshed hyphae.
Colony = the sometimes circular body of fungal growth that is visible to the unaided eye. Can be
comprised of ... Show more content on Helpwriting.net ...
To prepare a wet mount slide you begin with the substance at hand. The specimens studied in the
laboratory using this type of slide were a hay infusion, a yeast suspension, and the mold specimen.
For the hay infusion you begin with placing two drops of the suspension in the center of a clean
microscope slide using a transfer pipet. The specimen must be immediately covered with a cover
glass completing the wet mount slide. The yeast suspension is transferred from the tube to the slide
using a flame sterilized inoculating loop. Immediately cover the specimen with a cover glass. The
stained yeast suspension is prepared the same way except that the suspension is mixed with a drop
of lactophenol cotton blue placed on the slide prior to transferring the yeast. The mold must be cut
from the petri plate and placed on top of the drop of lactophenol cotton blue already placed on the
microscope slide. After it is covered it may be studied under the microscope. 3. State the scientific
name of the yeast studied in the laboratory.
Saccharomyces cerevisiae is the scientific name of the yeast studied in the laboratory. 4. Name the
medium upon which the mold was cultured.
Sabouraud agar is the medium upon which the mold was cultured. 5. Name the stain routinely
employed on fungal specimens.
Lactophenol cotton blue is a stain routinely used on fungal specimens. 6. List two methods by which
the mold specimen was examined.
The mold

Diagnosis of an Infected Patient Essay
Diagnosis of an Infected Patient
Infection is the invasion and growth of microorganisms such as bacteria, viruses, and parasites that
are not normally present within the body. A prokaryotic cell is a simple cell that does not have a
nucleus. One of the most common types of prokaryotic cells is a bacterium. Bacteria are
differentiated by many factors including shape, chemical composition, nutritional requirements,
biochemical activities, and sources of energy (Tortora 76). A patient with an infection in the upper
respiratory system will need to have a sputum sample sent to the lab for further evaluation to
determine the cause in order to accurately treat the infection. While many microorganisms can be
the cause of infection, ... Show more content on Helpwriting.net ...
Spores can be stained using specific dyes, such as malachite green, that are absorbed by spores in
the presence of heat (Noonan).
Escherichia is a genus of aerobic gram–negative rod–shaped bacteria of the family
Enterobacteriaceae that form acid and gas on many carbohydrates, such as dextrose and lactose, but
not acetone, which include occasional pathogenic forms, including some strains of E. coli which are
normally present in the human intestine as well as other forms which typically occur in soil and
water (Webster). Escherichia coli is a gram–negative bacilli that rarely varies in shape and size and
when stained often resemble safety pins because the ends of some bacilli stain more densely than
does the middle; which is a characteristic called bipolar staining which is common in enteric gram–
negative bacilli (ASM). Gram negative cells have a thin cell wall layer and will stain red to pink.
The staining process is the same as Gram positive, requiring four steps: applying a primary stain,
adding a mordant, then rapid decolorization and completing with a counter stain. Applying the
alcohol for decolorization dissolves the outer membrane and leaves small holes in the thin
peptidoglycan layer through which the crystal violet–iodine diffuse. The gram–negative bacteria is
colorless after the decolorization; therefore adding safranin

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

Gram Staining Lab Report
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
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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

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
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

Advantages And Disadvantages Of Haematoxylin
Abstract
Haematoxylin is a natural dye which stains poorly unless it is combined with different metallic salts
known as mordants. A mordant is a metal with a valence of at least two. The most common metals
used in histology are aluminum and ferric iron (both have a valence of three).
The combination of haematoxylin and a mordant is called a haematoxylin lake. There are several
haematoxylin lakes and they vary in colour. The different types of haematoxylin lakes are: Alum
haematoxylin solutions
An effective nuclear staining alum haematoxylin solution requires three main items: the dye
(haematoxylin or haematein), mordant (an aluminum salt) and the solvent (water being the
simplest). These solutions contain potassium alum or ammonium alum as ... Show more content on
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Hence, it is useful for photomicrography. This technique uses iron alum as a differentiating agent
and as an oxidizing agent which oxidizes haematoxylin to haematein. The staining time is 30 to 45
minutes at a temperature of 56℃. Heidenhain's iron haematoxylin is used to demonstrate
mitochondria, chromatin, chromosomes, nucleoli, centrioles, nuclear membrane, cross–striations of
muscle fibers and myelin.
Weigert's iron haematoxylins
A stain solution used for staining cell nuclei when demonstrating collagen and muscle with the van
Gieson stain and trichrome connective tissue stains. The mordant is acidified ferric chloride and the
staining time is 20 to 30 minutes. Wiegert's iron haematoxylin stains cell nuclei on sections which
are decolourised by the acid staining reagents and were previously treated with a solution of
haematoxylin which contains potassium alum or ammonium alum as the mordant.
Verhoeff's iron haematoxylins
An elastic tissue stain which is prepared immediately before use due to its rapid oxidation of
haematoxylin. The staining time is 25 to 60 minutes. The mordant used is ferric chloride and it is
also used as a

Bizzozero Staining Procedure
An experiment Evaluating whether PCNA supports the classification of Bizzozero (1894) tissues
tissues placed in three categories, reflecting their replicative potential.
Introduction
The aim of this experiment was to utilise PCNA and staining procedures to determine whether
different tissue cell samples proliferate. Tissue which exhibited brown stains prove cell proliferation
and mitotic divisions, this would suggest it being the in the first group of Bizzozero's grouping of
tissue types. Tissue samples which showed no brown staining meant no cells had proliferated and
therefore were of a different tissue type that do not regenerate while present in the body. The PCNA
protein is present during cell division/mitosis therefore, its presence suggests that cell proliferation
is occurring or has occurred. An area can be stained using brown diaminobenzidine (DAB) by using
an antibody that is against the PCNA protein. A primary antibody then attaches to the PCNA
molecule, and a secondary antibody (horse radish peroxidase) attaches to the primary antibody. A ...
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Tissue sample B showing– no brown staining visible:
Tissue sample C showing minimal brown staining:
Conclusion
The three different tissue types exhibit differing levels of cell replication. Proliferation did not take
place in tissue sample A compared to Tissue sample b having very minimal cell proliferation. The
experiment conducted supports Bizzozero's 1894 article which illustrates that based on where the
cells originate from, the cell proliferation will differ.
References
This experiment supports Bizzozero's (1894) claims of there being three different groups of tissues,
based on its proliferation rate. Bizzozero G (1894) British Medical Journal i (728– 732.
2 Carmen & Filipe (1993) Histochemical Journal 25: 843–853
3 Muskhelishvili L, Latendresse JR, Kodell RL, Henderson EB. (2003) J Histochem Cytochem.

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

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

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

Theory of Staining Techniques
Theories of Staining Techniques Staining bacteria with different dyes via staining techniques, allows
in distinguishing the microorganism from its backgrounds. Also, helps in studying different internal
structures such as vacuoles, cell walls and spores in details (Seeley and others 1991). Some staining
techniques such as Gram staining, endospore stain and capsule stain are some of the theories of
stains used in bacteriology today. Also, these staining procedures help in determining properties of
an unknown culture. Gram staining is a differential stain that helps in distinguishing between types
of bacteria and it is the most useful staining procedure used today (Seeley and others 1991). In this
kind of staining procedure, a basic ... Show more content on Helpwriting.net ...
However, a normal observation of an endospore staining would have "green stained endospores and
the rest of the cells without endospore cells" (Seeley and others 1991). In addition, if a simple stain
is used, the spores will appear clear because the walls of endospores resist stain penetration (Black
2005). FIG II A different kind of stain is the capsule stain. In this staining procedure, the capsules in
a cell are not stained intensely because they vary in thickness and can repel stains (Seeley and others
1991). Congo red is the primary stain in this procedure, which stains both bacterial cell and the
surrounding capsule (Seeley and others 1991). To start off, place several loopfuls of unknown
culture in Congo red solution on a glass slide. Then, allow the slide to air dry. However, do not
heat–fix as noted in the above two staining procedures. Next, flood the smear with Maneval's stain
for at least 1 minute, then rinse with water and blot dry. Following that, observe the slide under the
oil–immersion objective and record any findings of the capsules unstained ad blue or black
backgrounds. After observation of the slide, the capsule stain of the unknown culture appeared
unstained with a blackish background and the cells were reddish brown and they were large and
arranged in pairs, which indicates that there is presence of some bacterial

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
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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

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

Counter Staining Of Peroxidase
waxed and then rehydrated through descending graded ethanol series down to distilled water. To
block the endogenous peroxidase, the rehydrated sections were treated with 6% hydrogen peroxide
for 10 min. For epitope retrieval, sections were microwaved in citrate buffer, pH 6 for a total 20 min.
Non–specific staining had been blocked by superblock (UV block) for 10 minute.
Sections were incubated with the primary antibodies for 60 min. The antibodies used were galectin–
1 (Genemed, clone NBP2,CA, USA, diluted at 1:400) and galectin–3 (Genemed, clone 9C4, CA,
USA, diluted at 1:100).
Secondary staining kits were used according to the manufacturer's instructions (Thermo scientific
corporation Fremont, CA, USA). Counter staining was done with ... Show more content on
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Of the 43 CRCC, according to the ISUP grading scheme, nuclear grade distribution was as follows:
10 cases were grade 1 (14.9%); 20 cases were grade 2 (29.9%), 9 cases were grade 3 (13.4%), and 4
cases were grade 4 (6%).
Table 1: Clinicopathologicalparameters of studied cases (n=67)
Factor Number Percentage
Total 67 100%
Age 25–75 years (mean, 53.2)
Gender
Male
Female
42
25
62.7%
37.3%
Size
≤4cm
>4cm,≤7cm
>7cm.≤10cm
>10cm
11
23
18
15
16.4%

34.3%
26.9%
22.4%
Histopathological type
Clear cell RCC
Clear cell RCC with sarcomatoid differentiation
Papillary RCC typeI
Papillary RCC type II
Chromophobe type
35
8
9
7
8
52.2%
11.9%
13.4%
10.4%
11.9%
Site
Upper pole
Lower pole
Mid pole
Replacing most of kidney
28
19
8
12
41.8%
28.4%
11.9%
17.9%
Laterality
RT
LT
Bilateral
32
35
0
47.8%
52.2%
0%
Grade of clear cell RCCs
1
2
3

4
10
20
9
4
14.9%
29.9%
13.4%
6%
LN metastasis
Positive
Negative
Unreported
5
3
59
7.5%
4.5%
88.1%
Expression of galectin–1 and galectin–3
In adjacent corresponding tumor free renal tissue; galectin–1 was positively expressed in 27 (40.2%)
of specimens within the distal, proximal tubules and the glomeruli (Figure 1A). Galectin–3 protein
was positively expressed in 34 (50.7%) of specimens within the distal and proximal tubules.
However, the

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

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 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

Neurofibrillary Staining Procedure
Bielschowsky Stain Similar to the Golgi stain, the Bielschowsky stain uses a silver compound, silver
nitrate, as well as ammonium hydroxide to cause silver ions to adhere to the membranes of nervous
tissue. This technique is especially useful in when looking and neurofibrillary tangles and senile
plaque. When dyed, the color of the samples can vary depending on the amount of silver that binds
to particular parts of the specimen. The Bielschowsky stain stains the neurofibrillary tangles, axons,
and plaques a dark brown or black while the background remains yellow. Due to its ability to stain
senile plaques, the stain is commonly used to look at tissues diseased with Alzheimer's disease.
Hematoxylin and Eosin Stain (H&E) Indicated by its name, this method of hystogical staining
involves two dyes. The first of which is Hematoxylin. As a basic dye, hematoxylin works as an
acidophilic substance. Because of this, it stains nucleic acids blue and purple. Thus, with this stain
the nuclei of cells are stained blue. The second dye, eosin, is basophilic. Any basic or negatively
charged structures, like proteins with cationic amino acid group, are stained pink. Of the two, eosin
tends to be the overpowering stain, coloring cytoplasmic content, muscle and connective tissues,
erythrocytes, and various other cellular content. ... Show more content on Helpwriting.net ...
The three Nissl stain dyes are acidophilic in nature and bind to nucleic acids. In addition Nissl stains
are used to see Nissl bodies, or the rough endoplasmic reticulum, in neurons. The Nissl dye has
evolved and now varies in the type of dyes it contains –– most contain are toluidine blue or cresyl
violet –– but typically the stains result in the Nissl bodies and nucleic acids colored purple or

Synapsin Staining Report
Discussion
Based on the results of this experiment, it can be stated that there was no correlation between
serotonin and synapsin staining in both Camponotus floridanus and Pogonomyrmex badius. The
quality of synapsin and serotonin staining varied among all the individuals in the lab, some
individuals would get good quality stains, while others get subpar stains. This would be due to many
factors such as, amount of time spent in blocking solution, fixative, and both primary and secondary
antibodies, dehydrating the brains for too long. The initial hypothesis was that there would be a
large trace of serotonin and synapsin staining in the mushroom bodies and optic lobes of both ant
species as both areas of the brain are critical to their survival, with respect to olfactory sensitivity
and visual processing (Heisenberg 1998; Holldobler 1976). But, the quality and trace of serotonin
and synapsin staining was not significant across almost all of the brain samples. This signifies that
samples were affected by an outside source, thus causing less than desirable staining results.
The optic ... Show more content on Helpwriting.net ...
1964). There was a statistically significant effect of time spent in the blocking solution and the
fixative and staining quality. In future experiments, the time samples are placed in blocking solution
and fixative should be monitored more closely and left for a sufficient amount of time to get better
and more accurate results, concerning staining quality. On the contrary, there was a positive
correlation between the amount of time the samples were left in the antibody solutions and staining
results. The longer the samples were left in the antibody solution, the better the staining results were
as attested by the statistical

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
content on Helpwriting.net ...
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

Lab : Differential Staining- Visalization Of Bacterials...
Lab Title: Differential Staining– Visalization of Bacterials Cell Strutures Lab
The Aim of the lab: the purpose of the lab was for students to be able to differential between
endospore and vegetative cells by looking at their cell sturtures.
Materials:
Glass microcope slides
Bursen burner
Inoculating loop
Sharpie pen
Sterile Water
Beaker with boiling water
Malachite green ( primary stain).
Safranin (counterstain)
Bibulous paper
Method:
Prepare smear as directed by professor during the first few weeks of class. Make sure to heat fix the
smear to prevent it from been wash out during the experiement.
Put alittle drops of Malachite green while while the slide is seating face up on a boiling beaker for
5minutes.
Rinse the silent gently with distilled water to get rid of the stain and make sure to place the slide
over a staining container to prevent containmation of other lab equipments.
Put few drops of safranin on the slide, let it sit for about two minutes.
Rinse gently with distrilled water and remove any let over water.
Blot the slide dry and allow it to air dry
Use the microcope to examine the slide under a 100x oil immersion lens.
Starch and write down any specific details of specific cells
Dispose the slide in the appropriate waste container
Results: were starch and given to Professor Nathan in lab
Disscusion
▪ The lab was done to visualize the cell structure of the endospore. The endospore is used to
determine resistance spore of

Comparing The Cellular Morphology Of Table 2
Comparing the cellular morphology of table 2 to their respective pure culture in table 3. B. cereus
presented with a white colony, round colony morphology, smooth margins and flat elevation in both
pure culture and isolated culture; E. coli presented with a Yellow colony, round colony morphology,
smooth margins, and flat elevation; S. aureus presented with a White colony; round colony
morphology, smooth margins, and raised elevation.
In comparison of the cellular morphology of each bacterium in the mixture (table 2) to their
respective pure culture (table 3) showed that Bacillus cereus, Escherichia coli, and Staphylococcus
aureus are present in the mixed culture as their respective cellular morphology was the same as
compared to the pure ... Show more content on Helpwriting.net ...
However, additional tests can be performed to further differentiate the three bacteria from one
another. One example is the BactiStaph test for the Staphylococcus genus (in this case S. aureus)
(Summers, Brookings and Waites, 1998). Which relies on the principle of detecting coagulase
(clumping factor) using fibrinogen, and detecting protein A with immunoglobulin G. As result of
these surface markers present on most strains of S. aureus will test positive for BactiStaph test
(Summers, Brookings and Waites, 1998; Harris, Foster and Richards, 2002); Another test to
differentiate E. coli and B. cereus from S. aureus is by the basis of motility. Using either MAST
motility test or hanging drop method differentiate E. coli and B. cereus from S. aureus, as the two
bacteria are motile (Mitchell and Kogure, 2006); Lastly, since neither E. coli nor S. aureus produce
endospores, whilst B. cereus under the right conditions does produce endospores. By using
techniques such as Dipicolinic acid assay or Schaeffer–Fulton spore stain can be used to assess the
presence of spores in B. cereus (Hindle & Hall, 1999).
Three plating methods can be used to produce well separated single colonies, streak plate procedure,
spread plate and the pour plate procedure (Sanders, 2012). Spread plate procedure is used to
separate microbes contained within a small sample volume (e.g. mixed broth culture) which is then
spread over an agar

The Staining Of Bacteria Are Known As Differential...
The staining procedures used to differentiate the types of bacteria are known as differential
technique of staining. The simple methods of staining impart same color to all types of bacteria and
other biological materials. The principle behind this differentiation is due to the variation in physical
and chemical properties of the cell. Consequently, reaction occurs differently to reagents. In
handling of the sputum when testing for the presence of bacteria pathogen one has to ensure that
there is no extraneous bacteria to contaminate the specimen. The sample is refrigerated for a
maximum of twenty–four hours. The sample should not be frozen or stored at room temperature.
Ensure that the minimum amounts of the present antibiotics that inhibit bacterial growth are not
visible to the eye. One should differentiate pathogenic and normal flora bacteria. The identification
of the bacteria is a step by step process that involves biochemical, molecular and immunological
tests and observations. To determine the viable bacterial numbers in the sputum sample, the sample
is homogenized with dithiothreitol and glass beads in order to determine the method which
recovered the greatest number of viable bacteria. Continuous monitoring systems of mycobacterium
report higher contamination rates than traditional radiometric technologies. The first step in
analyzing fresh sputum is the gram stain test which seeks to identify the type of bacteria in the
sample. If the sample is seen to contain

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
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

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 ...
Show more content on Helpwriting.net ...
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

Unknown Lab Report
Purpose The purpose of the Unknown Lab is to practice and implement all that was learned in this
microbiology lab this semester about the different test used in identification of an unknown bacteria
and to effectively identify an unknown bacterium. Introduction The identification of unknown
bacteria are used in labs by microbiologist for the purpose of studying bacteria that cause diseases,
diagnosis of diseases and for treatment of the diseases. Therefore, it is important for them to
effectively identify the right bacteria that is causing harm to people, animal or environment and treat
it successfully. Hence, discussing the different type of test used and the processes of how one could
identify the unknown bacteria. They are hundreds of ... Show more content on Helpwriting.net ...
Fermentation test are used to detect the use of substrates and sugars to identify the unknown
bacteria. Hence, bacteria that ferment sugar with the production of acid or acid and gas and bacteria
that do not ferment sugar can be differentiate. For example, Phenol Red fermentation broth are used
to determine if the bacteria ferment sugars such as glucose, lactose, or sucrose, and phenol red is the
pH indicator added to detect or trap the acid or gas. Other fermentation broths are used such as,
Methyl Red– Voges Proskauer(MR–VP) broth or Voges Proskauer (VP); which determine ability
oxidize glucose to pyruvic acid to strong acid( lactic, acetic, formic) and

Essay On The Intensity Of Staining
our institute. The intensity of staining was graded as very weak, mild, moderate and marked nuclear
immunopositive reaction. Another cutoff of 35% was tested to compare the expected results. TNBC
was defined as the tumor that was ER (–), PR (–) and HER–2 (–) regardless the expression of
epidermal growth factor receptor (EGFR) and basal cytokeratins. Evaluation of pathologic response
Specimens without a residual invasive tumor in both the breast and the regional lymph nodes were
classified as a pathological complete response (pCR). Residual ductal carcinoma in situ was also
included in the pCR category. Otherwise the specimens that did not achieve pCR category were
classified as residual disease. Treatment protocol The chemotherapy regimen ... Show more content
on Helpwriting.net ...
Most patients 80.2% were at the age of 40 years or older, either in the whole cohort or TNBC
subgroup. However, in both mother group and TNBC subgroup, Table 1. Patient Clinicopathological
Characteristics of the Whole Cohort (Mother Group) and TNBC Subgroup Parameters Whole cohort
TNBC subgroup N (101) % N (23) % Age (years) <40 20 19.8 4 17.4 >40 81 80.2 19 82.6
Menopause Premenopause 60 59.4 13 56.5 Postmenopause 41 40.6 10 43.5 Grade 1 4 4 0 0 2 56
55.4 6 26.1 3 41 40.6 13 73.9 Multicentric tumors Yes 23 22.8 4 17.4 No 78 77.2 19 82.6 LVI Yes
46 45.5 12 52.2 No 55 54.5 11 47.8 Tumor stage T1 6 5.9 1 4.3 T2 31 30.7 6 26.1 T3 40 39.6 11
47.8 T4 24 23.8 5 21.7 *Ki–67 Low 25 24.8 2 8.7 High 76 75.2 21 91.3 ER/PR status Negative 33
32.7 23 100 Positive 68 67.3 0 0 HER–2 Negative 77 76.2 23 100 Positive 24 23.8 0 0 LVI,
lymphovascular invasion; ER, estrogen receptor; PR, progesterone receptor; HER2, human
epidermal growth factor receptors type 2. *High Ki–67 expression was defined as ≥14% Figure 1.
Treatment Design. KAMC: King Abdullah Medical City, TNBC: triple negative breast cancer, CR:
complete response (clinical), pCR: pathological complete response Table 2. Other TNBC Subgroup
Clinic–pathologic Characteristics Parameters TNBC subgroup N (23) % Pathological subtype IDC
22 95.7 ILC 1 4.3 Presence of DCIS (ductal carcinoma in–situ) No 17 73.9 Yes 6 26.1 Body Mass
Index (BMI) 18 – < 25 2 8.7 25 – 30

Staining Our Teeth Essay
Purpose:
What kinds of drinks will stain teeth the most? I thought it would be interesting to find out if all the
commercials you see about teeth being stained by coffee, tea, or soda were true.
Hypothesis:
Soda will harm the teeth by staining them worse than any other drinks. I feel this will happen
because my Aunts teeth are dark and she drinks a lot of soda.
Research: Our health is very important, and taking good care of our teeth is one way we can stay
healthy. There are many things that can affect the health of our teeth, like age, certain illnesses,
different medications, your genetic makeup, and how we care for our teeth. According to an article
in Discovery Health, good oral care can not only prevent illnesses and ... Show more content on
Helpwriting.net ...
On the 14th day I repeated the procedure and compared each tooth and documented results.
11. On the 21st day I took my last set of pictures and compared the staining of each tooth and
documented the results on paper.
12. Lastly, I created a graph to compare the discoloration of each tooth,using degrees of staining
from 0% – 100%. After each week I documented which drink caused the most degree of staining.
And after the 21st day I got my final results.
Results:
After the 7th day the soda appeared to darken the teeth the most and the tea was the drink that least
stained the teeth. By the 14th and 21st day, the soda remained the drink the stained the teeth the
most and the tea the least. With an end result of 70% stained from (soda), 60% stained from (coffee),
and 20% stained from (tea).
Conclusion: The results of my experiment were as I expected. I was shocked to see how dramatic
the change in color was and how quickly the teeth were damaged from all of the drinks over time.
My suggestion to people that enjoy drinking coffee, tea and soda, would be to visit the dentist
regularly and to clean your teeth every day. Try and remember to use a straw and to drink water after
your drink these

Mic Final Exams...
CONFIDENTIAL
AS/OCT2010/MIC455
UNIVERSITI TEKNOLOGI MARA FINAL EXAMINATION
COURSE COURSE CODE EXAMINATION TIME
GENERAL MICROBIOLOGY MIC455 OCTOBER 2010 3 HOURS
INSTRUCTIONS TO CANDIDATES 1. 2. This paper consists of ten (10) questions. Answer ALL
questions in the Answer Booklet. Start each answer on a new page. Do not bring any material into
the examination room unless permission is given by the invigilator. Please check to make sure that
this examination pack consists of: i) ii) the Question Paper an Answer Booklet – provided by the
Faculty
DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO
This examination paper consists of 5 printed pages
© Hak Cipta Universiti Teknologi MARA
CONFIDENTIAL
CONFIDENTIAL
2 ... Show more content on Helpwriting.net ...
(4 marks) What is the use of negative staining? (2 marks) c) Most genera of bacteria will lose the red
carbolfuchsin stain when decolourized using acid alcohol but those that are "acid–fast" retain the
bright red colour in ZiehlNielsen Acid–Fast stain. What could be the explanation for this colour
differences. (3 marks) You are given a bacterial sample and your task is to find out whether the
bacteria are motile or not. Suggest three (3) lab procedures that enable you to test on the bacterial
sample. (3 marks)
b)
d)

QUESTION 8 a) List down three (3) advantages of transformation. (3 marks) b) Describe the
mechanism of conjugation with the aid of a labeled diagram. (6 marks) c) What is the main
difference between conjugation and transformation? (2 marks)
© Hak Cipta Universiti Teknologi MARA
CONFIDENTIAL
CONFIDENTIAL
5
AS/OCT 2010/MIC455
QUESTION 9 Discuss in detail the importance of fungi in different fields : agriculture, industrial
and medicine. (10 marks)
QUESTION 10 Figure 1 demonstrates the patterns of oxygen used by different organisms incubated
for 24 hours in tubes of a nutrient broth.
m m
E
AJ
B a)
£y
^*WSP«t
Identify the possible group of organism that accumulate in tubes A to E as

Applying Staining Techniques to View and Identify...
Abstract The main objective of this lab was to identify different bacteria by simple, negative, and
gram staining. To view each bacteria cell, the bacteria was transferred aseptically to a slide, and they
were then viewed by using oil immersion, by a light microscope. From this lab, it was determined
that E. coli and B. megaterium are gram negative and B. subtilis and S. Marcesans are gram
positive.
Introduction The purpose of this lab was to view the different characteristics of bacteria by applying
various staining techniques. It is important to know the make up if a certain bacteria so an antibiotic
may be engineered to destroy the bacteria. From the gram stain, it was possible to determine which
bacteria was gram positive ... Show more content on Helpwriting.net ...
Distilled water
Three different staining procedures were then used for all four types of bacteria. The directions for
each staining process can be found on pages 18–19 of the lab manual. For simple stain, bacteria was
removed with a sterile inoculating loop and placed on a glass slide. Methylene blue was then applied
until the slide was covered. Distilled water was then poured on the slide until the methylene blue
was removed. The slide was allowed to dry. Next, oil was placed on the slide so that the oil
objective lens on the light microscope was employed. The bacterium was viewed and a sketch was
made. For the negative stain, a loopful of bacteria was placed on a slide. A drop of Nigrosin solution
was placed next to the bacteria, and the blood smearing technique learned in the first lab was applied
to cover the slide with nigrosin solution. A sketch was then made. Gram staining was more
complicated. First, two separate types of bacteria were used. One type was placed on one slide, and
the other bacteria were placed on the opposite side. Both bacteria were also placed in the middle of
the slide so they could be viewed together. Crystal violet, iodine and safranin were all placed on the
slide and washed off with distilled water. Once dried, oil was applied to the slide, and it was ready to
be viewed. Again a sketch was made.
Results The sketches were drawn on a separate piece of paper and then revised. A

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

Gram Staining Procedure Lab Report
Purpose:
The purpose of this lab is to identify a given unknown based on the previous experiment and lab
techniques that we have learned during this course. It was achieved, by preparing a gram staining
procedure, to help us identify the morphology of the bacteria, and to prepare a various of different
test, such as the starch test, oxidase, urease, citrate, MSA, Nitrate Reduction and MP/VP to help us
identify if the bacteria is able to produce the specific catabolism that it being testes for.
Procedure:
Gram Staining Gram Staining is a procedure used to distinguish between gram–positive and gram–
negative bacteria, where one of the main differences is the cell wall. Gram–positive bacteria contain
multiple layers of peptidoglycans and gram–negative lacks of peptidoglycans in the cell wall.
Overall, is a short procedure that consists of the following steps: first apply the primary stain
(crystal violet), second apply the mordant (Gram's iodine), third apply decolorizing agent (ethanol or
ethanol acetone) and finally apply secondary stain (safranin). Another purpose of gram staining is to
determine the bacteria's morphology. In gram–positive bacteria, the stain retains the dye ... Show
According to (Case, 1946) urea is a waste product of protein digestion in vertebrates and is excreted
in the urine. The presence of urea liberates ammonia from urea which is helpful in identifying
bacteria. The pH of a medium urea is about 6.8 or below, if tested positive, the pH will have an
increase to about 8.4 or above causing the solution to go from a yellow color to a hot pink color, this
is mainly due to the ammonia produced. This experiment is done by following the lab of
"Preparation of Smears." Unknown 3, showed a change from a yellowish solution to a hot pink
color, helping to concluded that it tested positive to having a pH of 8.4 or above and able to liberate

Differential Staining Procedure
There are two types of staining: simple staining and differential staining. Staining is used to identify
unknown bacterium including the structures within it and aseptic techniques should always be used.
Bacterium is a transparent cell. Due to this, bacteria has to be stained and identified to be
categorized. During simple staining, a sample of bacteria is taken from a culture. First, water is
placed on a slide with a loop then, the bacteria is scratched onto the slide. It must dry completely
before it is fixed to the slide with the use of a Bunsen burner. One stain such as crystal violet is
placed on the slide for one minute to add color. Once it has been rinsed off and dried with blotting
paper it can be viewed under a microscope. A differential ... Show more content on Helpwriting.net
...
Bacteria that have a flagella are known as motile and the bacteria that do not are non–motile. The
motility test is conducted by flaming an inoculation needle. After grazing the top of a culture, then
placing the needle straight down into a tube of the motility media and lifting the needle straight out.
Triphenyltetrazolium chloride (TTC) is turns the bacteria to a red color making it easier to see if the
results are motile or non–motile. If the bacteria forms a straight line it is non–motile, however if the
bacteria is spread throughout the tube it is classified as being

Staining Teeth Essay
Logically, we could assume that coffee isn't the only substance that has ever stained your teeth.
Especially if you have been accumulating stains over the long–term. Therefore, you want to first cut
out anything else that may be sabotaging your smile.
You have the usual suspects, like dark berries and cola. But a few other surprising foods and drinks
could be making your stains more obvious.
For example, if you think that sticking to white wine is better for white teeth, you may be wrong. As
it turns out, the acidity in white wine can make your enamel more porous.
So when you do eat or drink something that is overtly staining, it travels deeper into the surface of
the tooth. This can make the stain darker, more obvious, and tougher to ... Show more content on
Helpwriting.net ...
7. Change the way you brew. And for that matter, the way you grind. Dr. Scott Frey of FreySmiles
has done quite a bit of legwork in determining which methods stain the most.
According to his findings, Turkish and espresso–making methods carry the most stain–creating
probability. Additionally, he estimates that many household coffee makers are comparable to the
pour over method. The pour over comes in at number four on the spectrum of methods that stain
teeth.
All the way at the very bottom is the cold brew method. Using coarsely–ground beans, this method
is hypothesized to have the least negative impact on maintaining white teeth. Contrary to what the
name implies, you don't have to drink cold brew cold. By all means, heat it up!
It's also ridiculously easy to make at home, which is nice considering how trendy it's becoming. To
make cold brew, all you need is coarsely–ground coffee, a sterilized jar, cold brew coffee bags, and
water. Or, just get an infusing pitcher suitable for cold brew.
Let the coffee and water steep together for 24 hours before straining well. That sounds like a long
time to make coffee, right? But the good news here is that you can make a large batch and store it in
the fridge. It will stay fresh for weeks!
On top of keeping your smile white, cold brew is much less acidic. And although I'm not big on
coffee, I think it tastes much better than the countertop drip

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