In the first part of the practical exercise, a gram stain reaction was performed on the sample collected from the carrot infected with soft rot. Gram stain result showed that the bacteria presented on the diseased carrot were gram negative and rod shaped, which were stained pink under the microscope. This result indicated that the bacteria did not have a thick peptidoglycan layer; therefore it was not possible for them to retain the dark crystal violet stain, even with the presence of the mordant iodine solution. Violet crystals diffused out of the bacterial membrane and got washed away by alcohol, thus the membrane absorbed the counterstain carbol fuschin. The process of Gram stain gave rise to a few possible errors. If each step was not carried out properly or if the timing was not right, it could give rise to false results. When Gram stain was performed, all crystal violet dye could have possibly not all been washed out, as this had occurred to other groups, resulting in some bacteria to appear as purple under the microscope. On the other hand, during the decolourisation step, if there was too much alcohol added or if the alcohol was left on the slide for too long, all bacteria could lose their purple colour and start to take up the counterstain dye, resulting in a false gram negative result. Streak inoculation was performed on nutrient agar (NA) and MacConkey agar (MAC) plates. There are a few possible errors that could occur at this stage as well, due to improper application of aseptic methods. The agar plates could have been contaminated with microbes from other sources, and this could also affect the subsequent steps of the experiment. At this point, the first postulate was satisfied, as supported by the class data for Gram...
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...on cutting edge techniques gene identification and DNA microarrays, where the complete genomes of the disease causing microbes are determined, together with the complete genomes of different hosts that they infect (Cummings and Relman, 2000). These host-pathogen relationships are still yet to be determined, based on these modified Koch’s postulates and they promise many future successes for microbiologists to determine the aetiology of microbial diseases.
F. Conclusion
Without all of Koch’s postulates being satisfied, it is not adequate to conclude that E. carotovora is the only causative bacteria for soft rot in carrot. With all postulates validated except for the last, it can be concluded that due to a few suggested errors, another species is found that is likely to be similar to E.carotovora in its ability to cause soft rot, gram stain reaction and cell shape.
Table 6 shows the results of the biochemical tests. The isolate can obtain its energy by means of aerobic respiration but not fermentation. In the Oxidation-Fermentation test, a yellow color change was produced only under both aerobic conditions, indicating that the EI can oxidize glucose to produce acidic products. In addition to glucose, the EI can also utilize lactose and sucrose, and this deduction is based on the fact that the color of the test medium broth changed to yellow in all three Phenol Red Broth tests. These results are further supported by the results of the Triple Sugar Iron Agar test. Although the EI does perform fermentation of these three carbohydrates, it appears that this bacterium cannot perform mixed acid fermentation nor 2,3-butanediol fermentation due to the lack of color change in Methyl Red and Vogues-Proskauer
In her book, Dorothy Crawford gives biographies of the history of microbes which have brought humans diseases on a large scale. These include epidemics like yellow fever, tuberculosis, smallpox, acute respiratory syndrome, bubonic plague, syphilis HIV, the Black Death, malaria and cholera. It is worth to point out that her work is up to date because most of these microbes are still with us in this era. Crawford uses the historical bibliography of humans experience with microbes to show a fact that microbes shaped our culture through infection, disease, and pandemic. At the same time, the ever changing human culture has also largely influenced the evolutionary nature of microbes.
Jennifer Ackerman's main focus in her article The Ultimate Social Network, is that of the functions concerning bacteria within humans. Although scientists have had presumptions about humans being proficient in governing their body’s innermost structure, they soon come to recognize the sophistication of our inner space which holds an extensive plethora of bacteria and other microorganisms that lie within each and every one of us. Moreover, scientists' new and emerging view of how the human body operates, and the cause of increasing present-day diseases (i.e. obesity and different autoimmune disorders) are uncovered by analyzing effects of certain microbe species in our bodies. By italicizing on points such as the above, in conjunction with bacteria's genetic variations, and modern computing technology, the author proves that scientists are quickly progressing with the characterization the most prevalent species of microbes, which, in her opinion, is definitely paying off.
While the tube for specimen Cb turned a tannish white in the lower half of the tube while the top stayed the lavender inoculated tube color. Do to this evidence I determined that both specimens Ca and Cb cannot use the process Casein hydrolysis or Casein coagulation due to lack of soft or firm curds in both tubes. Since there was no casein curds formed, I concluded that specimens Ca and Cb also cannot perform the process of proteolysis. My conclusion is supported by the fact that there was no clearing of the medium. I have also determine that neither of my organisms can make the enzymes rennin, proteolytic or even proteases. I know my specimens cannot produce proteases due to the fact that there was no blue coloring in the tubes which means that the byproduct Ammonia was not produced to increase the pH. Since neither of my specimens can make these enzymes, I concluded that my specimens cannot break down lactose or casein. Although I did learn that specimen Cb can reduce litmus due to the evidence that the lower part of the tube turned a tannish white color with a purple ring at the top. This color change from a purple to a white means that the litmus was reduced turning it clear and leaving the white of the milk to show. Finally I know that specimen Ca cannot reduce litmus due to the fact that the tube had no change in
coli cells were grown at 37 degrees Celsius with calcium ions. These cells were then incubated in ice and placed into 4 polypropylene tubes. Each tube consisted of 25 microliters of E.coli cells. Two of the four were labeled with (+) while the other two were labeled (-). Positive was with samples that contained 100 pg/ microliter of pGLO, while negative was for the samples that did not. The 4 tubes were incubated in ice for 30 minutes, then heat shocked for 30 seconds at 42 degrees Celsius. The 4 tubes were then returned to the ice bath for 5 minutes. After the removal, .975 microliters of LB media was added to each tube at room temperature. The tubes were then shook at 225 RPM at 37 degrees Celsius for one hour. 300 microliters of cells were then extracted from the tubes and then placed in agar plates. The cells were spread across the plate and the incubated overnight at 37 degrees
The first step to the unknown is selecting an actual organism. The best way to select a culture is based on a high-quality distribution. Equally important, shaking up the broth tube facilitates in the distribution. Upon selection, a gram check for purity is performed. Step by step instructions for this procedure can be found in Benson’s, Microbiological Applications p. 99. Furthermore, an aseptic technique must be performed for this test and the entire tests following the unknown. The purpose of this test is to differentiate between gram positive and gram-negative bacteria. The key indicator of gram-positive bacteria is a purple stain and a pink stain for gram-negative bacteria. A slide is viewed with a microscope under oil immersion. Equally
The independent variable for this experiment is the enzyme concentration, and the range chosen is from 1% to 5% with the measurements of 1, 2, 4, and 5%. The dependant variable to be measured is the absorbance of the absorbance of the solution within a colorimeter, Equipments: Iodine solution: used to test for present of starch - Amylase solution - 1% starch solution - 1 pipette - 3 syringes - 8 test tubes – Stop clock - Water bath at 37oc - Distilled water- colorimeter Method: = == ==
After that bolt the slide dry with bibulous paper. After that examine the slide under the oil immersion lens. After determining the Gram stain reaction, 18 specific biochemical tests were performed for further analysis. The way of biochemical test was different but need to incubate at 37 degree Celsius. Phenol red lactose, phenol red dextrose, phenol red sucrose, methyl red, voges-proskauer, citrate utilization test, urea hydrolysis, and nitrate reduction are the media which are in test tube as liquid. Which were use Inoculating loop to deep tube with assigned bacteria. Triple sugar iron, and citrate utilization are in slant and we use Inoculating needle to deep tube with assigned bacteria. Again, starch hydrolysis, casein hydrolysis, lipid hydrolysis, oxidase test and catalase test were test from agar plate which use inoculating loop. For those media, which were in agar plate, inoculate with loop by making a line streak down the center of the agar. After that all 18 medias need to incubate at 37 degree Celsius for 48 hours. After 48 hours, some media show bacteria’s characteristics and morphology without adding extra reagent. Some media need reagent to examine morphology and physiology. Experiment such as MRVP needs methyl red, Barritt’s A, and Barritt’s
Two unknown bacteria were provided that were labeled “12A” and “12B”. Both bacteria were then used individually following aseptic technique to create heat-fixed smears. Both bacteria were strategically placed on the slide in order to prevent cross contamination and inaccurate results. A total of three slides were made in order to ensure accuracy. The heat-fixed slides were then Gram stained using the procedure listed in the manual; followed by observation under a Leica Dm500 microscope. The slides were observed under 4X,10X,40X and oil immersion and both unknown reactions were double checked by Dr. McLaughlin.
Gram stain is one of the most important stains in determine the morphology and cell wall composition of the bacteria. The stain is positively charged and is attracted to the negatively charged surface of the bacteria; which produces the purple or red color of the gram stain. The gram stain results of unknown KK revealed that the bacteria species were gram-negative, red/pink, and rod shaped. Therefore, a MacConkey agar test will be conducted in order to differentiate two classes of gram negative
...standing the nature of relationship between the residing microbes inside human cells and about their function is very important to put an end to this war and to live in peace with the natural organisms that are benefitting human body and their survival has become our primary importance.
In this exercise, Penicillium was utilized, a common, safe, mold. Certain species of Penicillium will spoil fruits, vegetables, grains, and grasses. Other species will ripen various chesses. Still, other species are used in the production of antibiotics. The species of Penicillium, italicum is provided for the lab because of its pronounced hyphae. Penicillium italicum, along with Penicillium digitatum attack citrus fruits post-harvest. In this experiment, the effect of Penicillium italicum on two types of citrus fruits and one non-citrus fruits were tested.
The discovery of genome sequencing by Fredrick Sanger and his team of researchers in the early 70’s gave rise to one of the most empirical research methods that was ever to exist. This revolutionary research technique has allowed scientists to finally encode organisms down to their most basic properties; helping massively in our understanding of pathways, reactions and functions of organisms. The technique involves analysing the DNA of an organism’s genome and therefore all the genes that compose it. The DNA from an organism is run through an electrophoresis gel and the sequence produced is taken up and interpreted by a computer program to then present the nucleotide sequence of the organism. Genome sequencing of pathogenic organisms has lead to huge advancements in the fight against infectious diseases within human and veterinary medicine; three notably virulent infectious diseases of the veterinary world are bluetongue virus, equine strangles and bovine tuberculosis (Goodhead, 2012).
The term “microbiology” refers to the branch of study that deals with microorganisms. Microbiology is extremely important in today’s time for the crucial information that the study provides. Human’s have had a long and cruel history of disease and sickness, for example the bubonic plague, but microbiology gives scientists the ability to observe, study, and prevent sickness like the bubonic plague to ever happen again. At the center of microbiology lies the bacterial cell, one that differs from those of a plant or animal because it lacks a nucleus and membrane-bound organelles which, in turn are traded for pili, flagella, and in some cases a cell capsule. Bacteria that are capable of causing illness or disease are called pathogens, pathogens work by releasing toxins in the body or directly damaging the host’s cells. An article by Lise Wilkinson explains that the earliest categorizations of bacterial cells first occurred in the late eighteen-hundreds to the early nineteen-hundreds by scientists (at the time) O. Muller and C. Ehrenburg (Wilkinson, 2004). The observation and identification of unknown bacteria that emerge is crucial because these new bacteria might be pathogenic and cause illness so it is very important that the bacteria is identified as soon as possible in order to either prevent the upcoming illness or treat it. While the common person is unable to identify if they are carrying bacteria (which is very likely), specialized tests that are ran in a lab can identify different types of bacteria and can even help
To excel in the field of Biology is not merely my dream, but my passion. I have started on this path of never-ending discovery and I want to master this science. It would not be unjustifying to state that the world is a better place today because of the advances in biological sciences. It truly promises to be an ever-advancing profession on this planet where better cures are required for freshly determined diseases on a day-to-day basis. Gene Technology and Biotechnology are a boon to this world. Putting microorganisms to use in the formation of insu...