Wednesday, July 10, 2013

Literature Review [IanKang]


Our Selected Title:
  • Investigation on effects of various antibiotics on probiotics(Lactobacilius)
Our Research Question:


    • Do the antibiotics we use affect the 'good' bacteria as much as the "bad" bacteria?
    Our immune system is usually enough to destroy harmful bacteria, as we have white blood cells that attack them before they multiply. Nevertheless there are instances where it is all too much for our bodies, and they need help which is where antibiotics come in. This is where our research comes in. Firstly, for our research project to begin, we had to figure our and conclude upon which antibiotics and medicines we were going to use during the process. These are some of the various antibiotics and how they work:

    • Penicillin is one of the most effective, safe, cheap and used antibiotic in our modern world. Penicillin is often categorized into 2 parts. Penicillin V and Penicillin G. Penicillin V is more acid stable as compared to its counterpart which allows it to be given orally. Penicillin G however is given parenterally which means bypassing the stomach and intestines which is often administered through injection or implantation. This therefore enables Penicillin G to be administered in higher concentrations resulting in an increase in antibacterial activities. Penicillin works by penetrating and damaging various bacterias cell walls known as 'peptidoglycan synthesis' .
    • Tetracycline is also used commonly. Tetracycline's are a type of broad spectrum antibiotics which are commonly used for treatments in the areas of the urinary tracts and intestines. Mostly they are used to counter act 'Escherichia coli' or e-coli for short. It works by penetrating the bacteria cell through small gaps in the cell membrane which also prevents it from entering human cells. Then it binds to a part of the ribosomes which is what creates proteins in the cell. This binding makes it impossible for the cell to which keeps the bacteria from growing. As a result, tetracycline is known as a bacteriostatic (Stops bacteria replication) drug as opposed to a bacteriocidal (Kills the bacteria) one.
    Though I did not cover all the antibiotics in the world, those are the most common. However, this antibiotics kill both bad bacteria and even the good bacteria, namely probiotics. To compensate for this loss, numerous probiotic drinks like Yakult and Vitagen have been created/discovered. After researching, the top 5 most consumed beverages are Coke, Diet Coke, Pepsi, Mountain Dew and Dr. Pepper respectively. Following this, people usually drink a soda or just an ordinary drink following the consumption of a probiotic drink. Pertaining to this issue, we decided to test a few drinks to see the effects of these presumably normal drinks on the probiotics gained through the probiotic drinks mainly whether they would adapt and grow in the given environment or have a loss in numbers.

    References: 

    Adam Cloe (2011, August 4) 'How Tetracycline Works in the Body' , Retrieved 5th July, 2013 from http://www.livestrong.com/article/71431-tetracycline-works-body/

    John Sicher (2013, March 25), Retrieved 27th August, 2013 from http://www.beverage-digest.com/pdf/top-10_2013.pdf

    Associated Press (2011, March 17) ,Retrieved 27th August, 2013 from http://www.nbcnews.com/id/42132603/ns/business-consumer_news/

    Doug Kaufmann (2003, June 18), Retrieved 27th August, 2013 from
    http://articles.mercola.com/sites/articles/archive/2003/06/18/antibiotics-bacteria.aspx


    Monday, July 8, 2013

    Literature Review (Minh Tri)

    Chosen Research Topic: Investigation on effects of various beverages on probiotics(Lactobacilius)

    Since our topic is about different antibiotics and Lactobacillus. Lactobacillus, the probiotic, plays a significant part in our research. Since we are using Lactobacillus Casei as a representative for probiotics, we would like to make L. Casei most similar to the other probiotics to make the research accurate.

    There are many kinds of classifications, groupings of bacteria. One common one is the Gram Stain. How does Gram Stain work? As Monica(2012) said, Gram Staining involves 3 processes.

    The 3 Processes:

    Staining
    • The bacteria, cells, tested are stained with a crystal violet dye. Then, Gram's Iodine solution(iodine and potassium) is added to form a complex with the crystal violet dye. This complex is then becomes insoluble in water.

     Decolorization
    • A decolorizer such as ethyl alcohol or acetone is added to the cells, which dehydrates the          peptidoglycan layer, shrinking and tightening it. The crystal violet-iodine complex is not able to penetrate this tightened and shrunk peptidoglycan layer, and is thus trapped in the cell in Gram Positive Bacteria. On the other hand, because the peptidoglycan layer of the Gram Negative Bacteria is on the inside, under the outer-membrane and the periplasmic space, the decolorizer degrades the outer-membrane. Due to the thinner peptidoglycan layer of the Gram Negative bacteria, without the outer-membrane, the layer cannot retain the crystal violet-iodine complex and loses it's violet stain. 
    CounterStaining
    • Counterstaining uses a counterstain. An example of a counterstain would be the water soluble safranin. This counterstain, safranin, is added to the cells, bacteria tested, which would stain them(Gram Negative) red. This is because the Gram Negative Bacteria was emptied of the Crystal Violet-iodine complex and just got stained red. Since safranin is lighter than crystal violet, it does not disrupt the purple coloration in Gram Positive Cells. In other words, this safranin does not overwrite the already violet stained Gram positive cells. 
    Due to the differences in thickness of the peptidoglycan layer in the cell membrane between the Gram negative and Gram Positive Bacteria, Gram Positive Bacteria(With thicker peptidoglycan layer) retain the Crystal Violet during the decolorization process, while the Gram negative bacteria(With thinner peptidoglycan layer) will lose the Crystal Violet Stain and instead get stained by the safranin during the counterstain process. Eventually, at the end of the experiment, the Gram Positive Bacteria, under a microscope, will look dark violet or violet, indicating that they are Gram Positive. While the gram negative bacteria, will look red, like pink rods under the microscope.

    So the question to ask is, what is the difference between the Gram positive and negative bacteria? 

    The following characteristics are shown in Gram Positive Bacteria: (Wikipedia)
    • Cytoplasmic Lipid membrane.
    • Thick peptidoglycan layer. (multilayered)
    • Flagellum (Only in some species. If present, it contains two rings for support as opposed to four in Gram-negative bacteria because Gram-positive bacteria have only one membrane layer.)
    • Mainly exotoxins produced.
    The following characteristics are shown in Gram Negative Bacteria:
    • Cytoplasmic membrane
    • Thin peptidoglycan layer. (single layered)
    • Outer membrane containing lipopolysaccharide (LPS). 
    • Porins exist in the outer membrane.
    • Presence of periplasmic space.
    • Mainly endotoxins produced.
    Comparing the 2 characteristics above, we can see that the differences between Gram Positive and Gram Negative Bacteria are:
    • Presence of Outer membrane.
    • Presence of periplasmic space.
    • Thickness of peptidoglycan layer.
    • Presence of lipopolysaccharide.(LPS)
    • Toxins produced.
    From the differences, I can safely say the Gram Negative Bacteria is more resistant to antibiotics, as well as more "irritating" to Scientists. Let me explain.

    Melissa(2000) said, "the distinctive feature of gram-negative bacteria is the presence of a double membrane surrounding each bacterial cell. Although all bacteria have an inner cell membrane, gram-negative bacteria have a unique outer membrane. This outer membrane excludes certain drugs and antibiotics from penetrating the cell, partially accounting for why gram-negative bacteria are generally more resistant to antibiotics than are gram-positive bacteria."

    She also said that Gram negative bacteria have a great facility for exchanging genetic material (DNA) among strains of the same species and even among different species. This means that if Gram negative bacterium undergoes mutation, or acquires genetic material that confers resistant to antibiotic, the bacterium may later share its DNA with another strain of bacteria and that this another strain of bacteria can become resistant as well. This causes great pain to Scientists as Gram negative bacteria might get resistant to antibiotics faster, as well as unexpectedly, and is very "irritating" as these scientists have to make a new antibiotic to fight against these mutated bacterium.

    Coming back to our research, all the above is precisely why we use Lactobacillus Casei as the test subject of our research/experiment.

    LPS is known as an endotoxin, found in the outer membrane of the Gram negative bacteria. Injections of small amount of endotoxins have shown produce fever, a decrease and blood pressure and activation of inflammation.
    With LPS in their outer membrane, most Gram negative bacteria are either harmful or harmless, little, or none beneficial.
    We use L. Casei to represent good bacteria due to the fact that it is found in our body, as well as it being a probiotic. Of course, it is a Gram positive Bacteria. 



    References:

    Monica Z.B (2012, May 29). Gram Staining. Microbial Life. Retrieved July 9, 2013, from http://serc.carleton.edu/microbelife/research_methods/microscopy/gramstain.html

    Gram-Positive Bacteria. (n.d). In Wikipedia. Retrieved July 9, 2013, from http://en.wikipedia.org/wiki/Gram-positive_bacteria

    Gram-Negative Bacteria. (n.d). In Wikipedia. Retrieved July 9, 2013, from https://en.wikipedia.org/wiki/Gram-negative_bacteria

    Melissa K. (2000). The problem with gram-negative bacteria. Retrieved July 9, 2013, from http://www.anapsid.org/gramnegative.html


    Literature Review (Htet Wai Yan)

    Selected title


    • Investigation of effects of various beverages on probiotics (Lactobacillus Casei).


    Research question


    • Do the beverages we consume affect the probiotics (lactobacillus) or it's growth in our body? If so, how?

    Hypothesis


    • Beverages do affect probiotic growth and we expect less than 50% of them terminated.


    Introduction to probiotics and antibiotics



    • The shortened version of our sub-research is actually just "Probiotics vs Antibiotics". We are trying to find out whether antibiotics slows the progress of the growth of probiotics or even on the very extreme, stops the growth of probiotics. However, before we move on to further complicated areas, let us get the basic definitions right. Starting with Probiotics, let us break down the word 'probiotics' to 'pro' and 'biotics'. From this, it should be easy enough to guess what this word 'probiotic' means. With "pro" being 'for' (in a way) and taking 'biotic' as a substitute for 'bacteria' (although its actual meaning is 'living'), probiotics are live bacteria that benefits the host it depends on. It is like mutualism in symbiosis in biology where both organism benefits. On the other hand, antibiotics is something that disapprove the growth of bacteria, seen from the word 'anti' as 'against' and 'biotics' again as 'bacteria' though its actual meaning may differ. The proper definition for the term 'antibiotics' are drugs used to treat bacterial infections. So these antibiotics are designed to terminate harmful bacteria, but the no one is sure what will happen to the harmless and beneficial ones who are often trapped in the crossfire. So we want to find out what will be the result of this matter. With lactobacillus as the probiotic and other related antibiotics as the antibiotic, we want to see if these lactobacillus are affected and if so, how? Also, we would like to find out what we can do to turn the tables to a win-win situation.


    Introduction to beverages

    • Inside us, there are the naturally occurring antibodies 'manufactured' by our immune system that are so called 'programmed' to detect and eliminate or neutralize the foreign threats in our body. However, they too have a limit and antibiotics for medical use are often brought in to help in facing the more dominant threats. With antibiotics introduced, there are positive benefits, but also negative impacts. These 'negative impacts' can be known as the antibiotic's side effects as stated in the prescription of these antibiotics. These side effects are caused by the antibiotics itself when performing its function as the harmless and beneficial bacteria are often caught in friendly fire, which ultimately disrupts the balanced composition of intestinal flora. These 'good' bacteria are called probiotics as stated in the above paragraph. As a result, we take probiotic drinks to counter this issue. Still, most probiotic drinks are required to be taken with an additional beverage. Now, we arrive at our research title, which is find out whether these beverages taken have any effect on the probiotics inside and outside our bodies.



    Purpose and Importance


    • Why is this important? It is rather an easy question to answer. To start with, both of these 'biotics' (not scientifically used here) are of benefit to us humans, with the only but major problem here is their uncooperative nature they have with each other, which is them conflicting among themselves, which eventually affects their main purpose, our health. Our health is compromised when these two conflict with each other, with the antibiotic unintentionally terminating the probiotics along with harmful bacteria, which eventually affects us with side effects. This happens when antibiotics terminate the probiotics which destabilizes our immune system, resulting in well known 'antibiotic side effects'. So our purpose of this experiment of testing the effects of various antibiotics on probiotics, particularly lactobacillus (due to it's nature of it strains mostly being probiotics), is to be aware of the conflicting relationship these two so that we are able to compromise less of our health. In other words, we want to know which antibiotics is better suited to which bacteria/ illness with little side effects, so that we are able to cut down loss from 'friendly fire' among probiotics and antibiotics, so that less of our health is compromised with more benefits.
    • If possible, we would try to answer (in theory) question of turning the tables around and seeing whether we are able to make these two friendly agents work with each other to fufill their main cause.

    References

    Literature Review (Ethan Ng)

    TOPIC QUESTION
    • Investigation on effects of various beverages on probiotics(Lactobacilius)

    HYPOTHESIS
    • Beverages do affect probiotic growth and we expect less than 50% of them terminated.

    INTRODUCTION

    Lactobacillus are bacteria which are rod shaped. They are generally considered to be beneficial to the body, as some strains posess potentially anti-inflamatory and anti-bacterial properties. They are also considered as probiotics. Such probiotics are often used in clinics and hospitals to replenish good bacteria populations after patients suffer illnesses which deteriorate bacterial colonies in the stomach, intestines etc.

    As these probiotics are often treated as supplements to increase or maintain health, we wanted to find out if such supplemental regiments would be affected by common everyday drinks, such as sodas, milk, tea, coffee, and energy drinks. Thus from the effects we could then see and perhaps recommend or advise against the intake of the said drinks whenever a patient was taking any probiotic supplements.

    PURPOSE

    As such we chose the 5 drinks mentioned above as they were regular, common drinks people take in their daily routines and that if any of the said drinks were found to have an effect increasing growth of the Lactobacillus, they could then easily be acquired and used to increase the effectiveness of the probiotic drinks. This investigation is also one which has not been explored in any major conceivable tests and is one that is relevant and useful, and such, it was chosen.

    Saturday, July 6, 2013

    Hypothesis

    Selected title


    • Investigation of effects of various beverages on probiotics. (Lactobacillus Casei)


    Research question


    • Do the beverages we consume affect the probiotics (lactobacillus) or it's growth in our body? If so, how?

    Independent variable


    • The beverages tested.


    Dependent variable



    • Amount of surviving probiotics (lactobacillus).


    Constant Variable



    • Constant type of probiotic (lactobacillus) 
    • Constant amount of probiotic (lactobacillus)
    • Constant amount of beverage 
    • Constant testing environment (temperature,etc)
    • Constant testing equipment 



    Hypothesis


    • Beverages do affect probiotic growth and we expect less than 50% of them terminated.


    Hypothesis (expanded)

    • There are two parts to this hypothesis, one is the question of whether it affects or not, another is the question of by how much. The first question comes in the process of this investigation while another is the end product. The first question is rather an easy question to answer with the help with the internet but you never know when it's really tested. Moreover, the use of lactobacillus as the probiotic and different beverages may result in varying results. The second one is no doubt the result we wish to achieve which will also be the root foundation of this research.




    Friday, July 5, 2013

    3 Possible Projects (Cont.)


    3 Possible Projects

    Title Research Question Independent Variable Dependent
    Variable
    Constant
    Variable
    Investigation on factors affecting effectiveness
    of a propellor.
    Does the angle of blades affect the effectiveness of the propellor? Angle of blade tilted. (°) Speed of propellor. (m/s) 1. Power given to propeller.
    2. Material of blades.
    3. Length of blades.
    4. Type of motor used.
    Investigation on effects of different antibiotics on good bacteria.  Do different antibiotics have different effects on good bacteria?  Antibiotics used. (mg) Amount of bacteria left. (µm) 1. Amount of antibiotics used.
    2. Temperature of experiment.
    3. Constant type of bacteria tested.
    Investigation on factors affecting rate of solar desalination.  Does the amount of light affect the rate of solar desalination? Light Intensity. (Lux) Amount of water desalinated. (ml) 1. Location of experiment.
    2. Constant amount of saltwater.
    3. Temperature of experiment.

    Tuesday, July 2, 2013

    3 Possible Projects.

    After finding various projects on ScienceBuddies, we have found many interesting research ideas. We found some interesting ones and MODIFIED them to these:
    1. Investigation of factors affecting the effectiveness of a propeller. 
    2. Investigation of effects of different antibiotics on good bacteria. (Lactobacillus Casei)
    3. Investigation of factors affecting the rate of solar desalination.

    Monday, July 1, 2013

    What is Scientific Method?


    What is a Scientific Method?

    A Scientific Method is a procedure to derive theories and phenomenas. Through this procedure, Scientists can acquire new knowledge, or correct old data. This method has been used since the 17th century and still used by current Scientists today. The picture below shows the Scientific Method.