Ampicillin and Kanamycin Resistant Bacteria Comparison

Ampicillin and Kanamycin Resistant Bacteria Comparison Antibiotic use throughout the world has increased tremendously over the decades. In the past, antibiotic resistance was most prevalent in areas of frequent antibiotic use, such as in medical or laboratory settings. However, the increasing use of antibiotics and antibacterial products outside of hospitals, such as in homes and schools, echoes the expansion of antibiotic resistant bacteria (LBC Biology Staff, 2010). One major source of the growing problem is that antibiotics are being over prescribed by doctors to millions of people around the world. It is currently believed that about only half of the antibiotics prescribed to patients are administered properly (Levy, 1998). In addition to over prescription by doctors, many patients misuse the antibiotics and further increase the spread of resistance. For example, some patients discontinue use of antibiotics upon feeling symptom relief, not at the end of their antibiotic schedule prescribed by the doctor. In actuality, patients are ki lling off the weakest bacteria, causing temporary relief, and allowing the stronger and more resistant bacteria to multiply at a faster rate (Levy, 1998). This and other types of antibiotic misuse have promoted the growth of strains of bacteria with resistance to antibiotic attack. This can be seen through studies that have shown Tetracycline resistance by normal human intestinal flora that exploded from 2% in the 1950s to 80% in the 1990s (Criswell, 2004). Other studies have shown Kanamycin, an antibiotic from the 1950s, has become clinically useless as a result of the prevalence of Kanamycin-resistant bacteria (Criswell, 2004). It has become visible that the development of resistance to any antibiotic, new or old, will happen in a matter of time (LBC Biology Staff, 2010). Due to the inevitability of mutation, natural selection, time and environmental conditions, resistance will be seen in more common areas like work and home. As a consequence of the every growing expansion of antiobiotic resistance, places previously thought to be uncontaminated like schools and homes have become overwhelmed with antibiotic resistant bacteria. In one household study, it was discovered that kitchen sinks contained many different types of resistant bacteria, primarily from food waste and human hands (Rusin et al., 1998). Only the application of strong bleaches and specific cleaning products on a regimented cleaning schedule led to a decreased amount of bacteria in kitchen sinks (Rusin et al., 1998). The cleaning products used in this study did not contain antibacterial ingredients, which helped reduce the spread of resistance by killing all bacteria instead of the most susceptible strains. Antibacterial products and cleaning supplies are less effective and in turn can lead to reproduction of stronger antibiotic resistant bacteria. The large amount of antibacterial cleaning products, food and waste combined with the constant water supply in sink drains allows for a greater chance of survival of antibiotic-resistant bacteria (Levy, 1998). Optimal conditions for bacterial growth with a wet environment cause a higher frequency of bacterial transmission of resistance (Perryman and Flournoy, 1980). In scientific laboratories, regulations are in place to monitor the disposal of solid and liquid wastes. Some regulations include specific waste baskets for toxic or contaminated substances and use of certain sinks only when dealing with harmful liquids in laboratory settings. This ensures that unnecessary amounts of harmful substances that could lead to resistance are not continually poured down laboratory sink drains. However, no such regulations are in effect in household environments. In a study performed in Oklahoma City the extent of growing antibiotic resistance was seen in multiple environments. Bacterial samples were gathered from sink drains in the Veterans Administration Medical Center, libraries, private homes, shopping centers, and other similar environments for comparison (Perryman and Flournoy, 1980). The goal of the experiment was to determine the types of resistant bacteria that were most prevalent in sink drains, the abundance of bacteria in sink drains, and the life span of bacteria in dry and wet environments (Perryman and Flournoy, 1980). Through testing, bacteria were found to have longer life spans in wet environments than in dry environments, and many bacteria survived for over 180 days in wet environments (Perryman and Flournoy, 1980). The high survival rate of bacteria in areas with constant water supply, such as in laboratory and kitchen sinks, supports the prediction that sinks are ideal environments for ample bacterial growth. In the afore mentioned study, bacterial growth occurred on plates containing the antibiotics gentamicin and amikacin, and it was determined that the sink drains from the medical hospital contained the highest amount of antibiotic resistant organisms. Overall, 88% of the sink drains sampled from the Veterans Administration Medical Center contained some type of antibiotic resistant bacteria (Perryman and Flournoy, 1980). While bacteria could come from other sources such as the patients and tap water, the great quantity of antibiotic resistant bacteria in all environments illustrates the need for a reduction in the overuse of antibiotics and the essential awareness of the consequences. Places with high levels of exposure to antibiotics and antibacterial products provide ideal environments for bacteria to develop resistance through replicated mutations or transmissions between bacteria. Some factors that severely add to the growing problem of antibiotic resistant bacteria include increased applications of antibacterial soaps and cleaning products, over prescription of antibiotics by doctors, misuse of antibiotics by patients, and improper care of waste products (Levy, 1998). Bacteria can become resistant to antibiotics through genetic mutation, transfer of the mutation between bacteria, or transmission of the mutated DNA on a plasmid between bacteria when the resistant gene is carried on the plasmid DNA. A plasmid is a relatively small piece of circular DNA that is self replicating and independent of the chromosomal DNA of the cell. Resistant chromosomal DNA and plasmid DNA can be transmitted to the next generation through cell replication. Plasmids can be passed th rough bacterial conjugation, which involves a bacterium copying the plasmid with resistant DNA and inserting the copied plasmid into a second bacterium. Plasmid DNA can also be transferred through bacterial transformation when plasmid DNA invades another bacterium and is incorporated into the bacteriums DNA (Cognato, 2010). Understanding these problems and the mechanisms of resistance transmission is the first step in preventing further development of resistant strains of bacteria. The focus of the experiment at hand is to determine whether the bacteria located in a laboratory sink or in an apartment garbage disposal contains more antibiotic resistant strains. It was hypothesized that the apartment garbage disposal would contain more antibiotic resistant bacteria than the laboratory sink. This is due to the abundance of contaminated materials that pass through garbage disposals in comparison to the regulated materials that pass through laboratory sinks. The null hypothesis is that the amounts of antibiotic resistant bacteria that exist in the garbage disposal sink and laboratory sink will be equal. Many steps were needed to accomplish this research and obtain the sample bacteria to determine the resistance. Samples from the laboratory sink and the apartment garbage disposal were swabbed on agar plates to obtain a culture of bacteria. Colonies were selected based on growth and seclusion from the bacterial lawn. Individual bacteria were then streaked on master patch plates for each environment. After the bacteria had grown, individual colonies were selected to be streaked on antibiotic plates containing Ampicillin, Kanamycin, and Tetracycline. Antibiotic resistant bacteria were chosen from the antibiotic plates, separated and characterized. Next, plasmids from the antibiotic resistant bacteria were isolated and spliced using restriction endonucleases to determine band length of resistant plasmid DNA to help identify the type of bacteria. Competent E. coli cells were transformed with the control plasmid DNA to convey antibiotic resistance and support bacteria identification. Final ly, the bacterial DNA was replicated by polymerase chain reaction to amplify the 16S rRNA gene in hopes to obtain sequencing information of a known bacterium. It was predicted that resistant bacteria, for all antibiotics, will be Gram negative due to easier entry of resistant plasmid DNA into the cell. Bacteria with a thin cell wall layer and an outer membrane surrounding the peptidoglycan layer are Gram negative. Bacteria with a thick wall layer that do not have the peptidoglycan layer surrounding are Gram positive. Gram identity was verified through Gram staining, a KOH test, and observing growth on a MacConkey agar and Eosin Methylene Blue Agar plate. Methods Swab Plates A sterile cotton swab saturated in sterile phosphate-buffered saline was used to gather samples from the laboratory sink and an apartment garbage disposal. Bacterial samples from the disposal and lab sinks were collected from the underside of the drain. Bacteria were then swabbed onto Lysogeny broth agar plates (three per environment). Plates were placed into an incubator for 24 hours at 37Â °C. Following the incubation period, plates were removed, parafilmed, and refrigerated at 4Â °C until needed. Master Patch Plates Master plates were made by placing sixteen individual colonies onto a 44 grid on Lysogeny broth (LB) only plates. An inoculation loop was used to transfer the 16 individual colonies from the sample plate onto a grid of the master plate. Plates were labeled with D for the apartment garbage disposal and L for the laboratory sink along with a number (1, 2, or 3) to distinguish between swabbed samples. Plates were incubated at 37Â °C for 24 hours, removed, sealed with parafilm, and refrigerated at 4Â °C until needed. Antibiotic Patch Plates Antibiotic agar plates were made by mixing 8.4g agar with 12g LB powder and 600mL of distilled water (dH2O), and then autoclaved. After cooling, 2.4Â µL of Ampicillin, 1.2Â µL of Kanamycin, or 2.4Â µL of Tetracycline were added appropriately and plates were poured. One colony per grid of the master patch plate was obtained with an inoculation loop, and the bacteria were transferred in a line onto a corresponding grid on the antibiotic plates. The number of squares that contained bacterial growth was observed and recorded. One colony of the bacteria grown on the antibiotic patch plates was then streaked onto a new antibiotic plate to obtain individual colonies of bacteria for further study. Miniprep A liquid culture was performed in preparation for the Promega Wizard Plus SV Miniprep DNA Purification System, which was used to isolate plasmid DNA from antibiotic resistant bacteria. First, 5Â µL of antibiotic was added to a 5mL tube filled with a liquid medium made of LB. A single colony of bacteria was added to the medium and placed in a shaker at 37Â °C for 24 hours. The liquid culture was then transferred into an Eppendorf tube and centrifuged for 5 minutes at 4,400rpm. Liquid media waste was disposed of and the pellet was thoroughly re-suspended in 250Â µL of Cell Resuspension Solution. If the bacteria were Gram positive, 63Â µL of lysozyme would be added to the solution. Since the bacteria studied was Gram negative, the process continued with the addition of 250Â µL of Cell Lysis Solution was added to the Eppendorf tube containing the resuspended bacterial solution and the sample was mixed. Subsequently, 10Â µL Alkaline Protease Solution was added, mixed, and incubated for 5 minutes at room temperature. Then, 350Â µL Neutralization Solution was added, mixed, and centrifuged for 10 minutes at 13,500rpm. A Spin Column was inserted in a Collection Tube and the clear lysate was decanted into the Spin Column. This was centrifuged for 1 minute at 13,500rpm and the flowthrough was discarded. The Spin Column was replaced, 750Â µL of wash solution was added, and the solution was centrifuged for 1 minute at 13,500rpm. The flowthrough was discarded, and this process was repeated with a 250Â µL wash. The solution was centrifuged for 2 minutes at 13,500rpm. The Spin Column was transferred to a 1.5mL Eppendorf tube. Finally, 50Â µL of Nuclease-Free Water was added and then the solution was centrifuged for 1 minute at 13,500rpm. The column was discarded and the DNA was stored at -20ËÅ ¡C. Gel Electrophoresis DNA electrophoresis was used to determine the length of the plasmid DNA of the environmental samples and Blue plasmid control (pKAN). First, 0.7g of agarose powder was added to 70mL of 1X TBE. The solution was heated in a microwave for 1 minute so the agarose powder was completely dissolved. After the mixture cooled, 3Â µL of Ethidium bromide was added and the gel was taken out of the mold and put on the rig. The gel was submerged in a 1X TBE buffer. The wells of the gel were filled with 10Â µL of a mixture containing 8Â µL of plasmid DNA and 2Â µL of plasmid dye, and the gel ran for 60 minutes on 80 volts. The 1% agarose gel was viewed under an ultraviolet light to compare lengths of DNA with the 1KB ladder. Gram Staining Gram staining was used to determine the Gram identity of bacteria. Bacteria that are Gram negative stained red and bacteria that are Gram positive stained violet. A colony of bacteria was added to an Eppendorf tube with 400Â µL of dH2O. After vortexing, 5Â µL of the solution was pipetted onto a slide. Once dry, the slide was passed over a flame to affix the bacteria to the glass, preventing the removal of bacteria. The slide was flooded drop-wise with crystal violet and iodine, and rinsed with dH2O for 5 seconds after the addition of each reactant. Ethanol was added until the color was no longer emitted, then rinsed with dH2O for 5 seconds. Safranin was added drop-wise for 1 minute and then rinsed with dH2O for 5 seconds. The slide was observed under a microscope to determine Gram identity. KOH Test The KOH test for Gram positive and negative bacteria was begun by pipetting 20Â µL of 3% KOH on a slide. After adding one clump of bacteria to the KOH, the consistency of the solution was observed. If the solution was thick, viscous and adhered to the inoculation loop, the bacteria were Gram negative. If the solution was thin and not viscous, the bacteria were Gram positive. MacConkey Agar Plate A MacConkey agar plate was streaked with antibiotic resistant bacteria from the garbage disposal and laboratory sink. After incubation at 37ËÅ ¡C for 24 hours, the plates were observed for growth to indicate Gram negative bacteria. The MacConkey agar plate also signaled lactose fermentation with the appearance of pink colonies. Eosin Methylene Blue Agar Plate (EMB) An EMB plate was streaked with antibiotic resistant bacteria from the apartment garbage disposal and the laboratory sink as well as a positive E.coli control. After incubation at 37ËÅ ¡C for 24 hours, the plates were observed for growth to indicate Gram negative bacteria. The EMB agar plate indicated strong lactose fermentation through the appearance of dark green metallic colonies and a lesser degree of lactose fermentation through the appearance of purple or pink colonies. Restriction Digest Restriction enzymes cut the control pKAN DNA at specific restriction sites identified by the NEBcutter V2.0. The enzymes used in restriction digest were BamHI and EcoRI in Buffer II, and PvuI and PstI in Buffer III. The reaction solution used in restriction digest consists of 10Â µL of DNA, 1Â µL of each enzyme, 2Â µL of NEBuffer, and 7Â µL of de-ionized distilled water (ddH2O) added together in an Eppendorf tube. The solution was centrifuged at 14,500rpm for 30 seconds and then incubated for 24 hours at 37ËÅ ¡C. A plasmid map created from the NEBcutter V2.0 was compared to a gel electrophoresis run on a 1% aragose gel with plasmid DNA. The gel electrophoresis compared Blue plasmid (pKAN) DNA that was uncut with the Blue control plasmid (pKAN) that was cut with restriction enzymes. Transformation After plasmid DNA preparation, 22Â µL of E. coli competent cells were added to three separate Eppendorf tubes. In one tube, 5Â µL of control DNA, pKAN, was added and stirred with the pipette tip. In the second tube, a negative control was made with the addition of 5Â µL of dH2O that was then stirred with a pipette tip. In the third tube, a positive control was made with the addition of 1Â µL of known pKAN, and the solution was stirred with a pipette tip. The tubes were then incubated in ice 30 minutes. The cells were heat shocked for 45 seconds at 42ËÅ ¡C and then placed on ice for 2 minutes. 250Â µL of pre-warmed (37ËÅ ¡C) SOC medium was added to all three of the Eppendorf tubes, and the tubes were then incubated in a shaker at 37ËÅ ¡C for 1 hour at 2,250rpm. Upon removal from the incubator, 75Â µL of each transformation were spread onto plates with a sterilized hockey stick. The transformed control DNA, pKAN, cells and the negative control dH2O transformed cell s were spread onto LB only plates, ampicillin antibiotic plates, and kanamycin antibiotic plates to determine if resistance to antibiotics was transferred in the transformation. The transformed positive control, known pKAN, cells was spread onto a LB only plate and a kanamycin plate since pKAN is known to be resistant to kanamycin. Plates were incubated for 24 hours at 37ËÅ ¡C and numbers of resistant bacterial colonies were observed. Bacterial growth on the control DNA, pKAN, transformation antibiotic plates would signal resistance to the antibiotic in the plate, and growth on the LB only plate would signal the existence of bacterial cells from the transformation. No growth on the dH2O negative control plates containing ampicillin and kanamycin antibiotics would signal a correct transformation as long as there was bacterial growth on the LB only plate. Growth on the positive control, known pKAN, transformation plate signaled the correct transfer of kanamycin resistant plasmid DNA into the competent E.coli cells. Polymerase Chain Reaction The Polymerase Chain Reaction (PCR) involved mixing a reaction cocktail that included 80Â µL of Nuclease-free water, 10Â µL of 10X Thermopol buffer, 3Â µL of 10mM dNTPs, 2Â µL of 11F @ 10Â µM, 2Â µL of 1492R @ 10Â µM, and 1Â µL of Taq polymerase @ 5000U/mL. The solution was then mixed through vortexing. Subsequently, 22Â µL of the cocktail was transferred to each of the 4 PCR tubes. A small portion of each bacterial colony was added to SOC medium and mixed. Then 5Â µL of SOC medium with bacteria was added to each tube. Tube 1 had environmental bacteria, tube 2 had different environmental bacteria, tube 3 had the control E.coli and 5Â µL of H2O was added to tube 4. The reactions were placed in the thermocycler in C4. The PCR cycling program consists of five steps. The first step is pre-denaturation in which the PCR mixing reaction cocktail is heated at 95Â °C for 5 minutes. The second step is denaturation, which involves heating the reaction cocktail at 95Â °C for 30 seco nds to unwind and separate the DNA. The third step is annealing, which is run at 50Â °C for 30 seconds to allow the 11F and 1492R primers to attach to the DNA template strands. The fourth step is elongation, which is run at 72Â °C for 45 seconds to allow the DNA polymerase (Taq polymerase) to add dNTPs and replicate the 16S gene. The fifth step is the final elongation, which is run at 72Â °C for 7 minutes. The hold between cycles is run at 4Â °C, and the PCR is run for 35 cycles. Gel electrophoresis was run to determine if a successful PCR reaction took place. 10Â µL of the PCR solution from each tube was mixed with 2Â µL of plasmid dye, and 10Â µL of the mixtures were loaded into the wells of the 1% agarose gel. Chi Squared Test of Independence A Chi Squared Test of Independence was run to determine if a statistically significant difference exists between the numbers of antibiotic resistant bacteria from the two environments. The number of grids on the antibiotic plates was recorded only if the bacteria grew on both the antibiotic plate and the LB only plate. The test was run on Vassar Stats and gave a p-value to correspond to the data and indicate if there was a significant difference. Results Swab and Master Patch Plates After the incubation period of 24 hours at 37 C, the swab plates, labeled L for laboratory sink samples (L1-L3) and D for garbage disposal sink samples (D1-D3), were observed and found that 100% of the environmental bacteria grew (Figure 1). Bacteria growth in both environments was indicated by white colored spots or streaks within the plates grid. Master plates were observed from both experimental environments and found to have growth on all of the 16 grids on each plate (Figure 2). Antibiotic Patch Plates From the garbage disposal sink, the three samples all had some level of growth (Figure 3). The following percentages were calculated by dividing the number of grids with bacterial development on the antibiotic plates by the number of grids with growth from the LB plates (Table 1). Plate D1 showed 100%, 62.5%, 0%, and 100% growth on the Ampicillin, Kanamycin, Tetracycline, and LB only plates respectively. Plate D2 demonstrated 93.75%, 93.75%, 0%, and 100% growth on the Ampicillin, Kanamycin, Tetracycline, and LB only plates respectively. Plate D3 showed 93.75%, 75%, 0%, and 100% growth on the Ampicillin, Kanamycin, Tetracycline, and LB only plates respectively. From the laboratory sink, all samples had bacteria development (Figure 4). Plate L1 demonstrated 100%, 93.75%, 12.5%, and 100% growth on the Ampicillin, Kanamycin, Tetracycline, and LB only plates respectively. Plate L2 showed 100%, 73.33%, 6.67%, and 93.75% growth on the Ampicillin, Kanamycin, Tetracycline, and LB only plates respectively. Plate L3 demonstrated 57.14%, 42.86%, 7.14%, and 87.5% growth on the Ampicillin, Kanamycin, Tetracycline, and LB only plates respectively. Chi Squared Test of Independence Data obtained from the number of antibiotic resistant colonies on the antibiotic patch plates was used to run the Chi-squared Test of Independence for Ampicillin and Kanamycin resistant bacteria. For Ampicillin resistant bacteria, the p-value obtained was 0.74. With one degree of freedom, the Chi-squared critical value of 3.84 obtained from a Chi-squared Distribution Table in comparison to the Chi-squared statistical value denoted no statistically significant difference. For Kanamycin resistant bacteris, the calculated p-value was 0.81. With one degree of freedom, comparison of the Chi-squared critical value of 3.84 found in a Chi-squared Distribution Table and the Chi-squared statistical value demonstrated no statistically significant difference (Table 1). Gram Staining, KOH, MacConkey Agar and Eosin Methylene Blue Agar Plates Four tests were used to determine the gram identity of bacteria from the experimental environments. The results showed that the three environmental bacteria slides were stained pink indicating gram negative bacteria (Figure 5, Table 2). For the KOH test, all three samples from both environments appeared viscous and thick, indicating gram negative bacteria (Table 2). The MacConkey Agar Plate was divided into three sections for the different antibiotic resistant bacteria. The environmental bacterial sample in Section 1 was obtained from the Ampicillin antibiotic plate L2 grid #3. The bacterial sample in Section 2 was obtained from the Kanamycin antibiotic plate L2 grid #14. The bacterial sample in Section 3 was obtained from the Kanamycin antibiotic plate D2 grid #16. All three samples in the three sections grew bacteria that were stained pink, indicating Gram negative bacteria that ferment lactose (Figure 6, Table 2). The Eosin Methylene Blue Agar Plate was sectioned off into four par ts and bacteria from three environmental samples and one E.coli positive control were plated. The bacterial sample in Section 1 was taken from the Ampicillin antibiotic plate L2 grid #3. The bacterial sample in Section 2 was obtained from the Kanamycin antibiotic plate L2 grid #14. The bacterial sample in Section 3 was gathered from the Kanamycin antibiotic plate D2 grid #16. The bacterial sample in Section 4 was obtained from an E. coli plate that was known to be Gram negative. Pink colonies formed in all four sections, signaling Gram negative identity of the bacteria and lactose fermentation (Figure 6, Table 2). Mini Prep and Gel Electrophoresis Promega Wizard Plus SV Miniprep DNA Purification System was run to isolate plasmid DNA. This plasmid DNA was run on a 1% agarose gel. The lengths of bands in Trial A could not be determined because the DNA in the wells did not run with the ladder. The Blue control plasmid, which was pKAN, was located in lane 3 in Trial A and Trial B and was used to indicate a successful Miniprep. The band length of the pKAN control DNA in Trial B was about 4,200 base pairs. An environmental plasmid found on Ampicillin streak plate L2, grid #3 was used in lane 7 in Trial A and lane 5 in Trial B. In Trial B, the base pair length of the environmental bacteria plasmid used in lane 5 could not be determined due to the appearance of many bands of varying length. An environmental plasmid from Kanamycin streak plate L2, grid #14 was used in lane 5 in Trial A and lane 7 in Trial B. The band length of this environmental plasmid in Trial B could not be determined due to the faint appearance of a band greater th an 10,000bp. Another environmental plasmid from Kanamycin streak plate D2, grid#16 was used in lane 6 in both Trial A and Trial B. The band length of this environmental plasmid in Trial B also could not be determined from the faint appearance of a band greater than 10,000bp (Figure 7). Restriction Digest In Trial A, restriction digest was used to cut the Blue control pKAN DNA with the enzymes BamHI, EcoRI, PstI, and PvuI. Lane 3 displays pKAN cut with PstI and PvuI. Lane 4 displays pKAN cut with BamHI and EcoRI. The lengths of the bands shown are about 4,000bp, 3,000bp, 2,500bp, 1,500bp, and 1,200bp.The lengths of the bands shown are about 1,700bp, 1,100bp, 750bp, 600bp, and 500bp. Lanes 5-8 contained environmental bacterial DNA that was cut with BamHI, EcoRI, PstI, and PvuI as well, but no bands were observed (Figure 8). In Trial B, restriction digest was used to cut pKAN DNA with only the enzymes BamHI and EcoRI. Lane 3 displays pKAN that was cut with BamHI, showing a band length that is about 4,200bp. Lane 4 shows pKAN that was cut with EcoRI, and the band lengths shown are about 8,000bp, 5,000bp, and 4,000bp. Lane 5 displays pKAN that was cut with BamHI and EcoRI, and the band lengths shown are about 4,100bp, 3,100bp, and 2,000bp. Lane 6 shows pKAN that remained uncut with a band length of about 4,200bp (Figure 9). Transformation Transformation was performed to convey resistance carried on plasmid DNA into competent E. coli cells. Blue plasmid control DNA (pKAN) was used for the transformation, which was successful. This was indicated by the growth of transformed bacteria on Kanamycin antibacterial plates (Figure 10). Polymerase Chain Reaction A Polymerase Chain Reaction (PCR) was used to amplify and prepare the 16S gene of rRNA. Gel electrophoresis was run on the PCR product to determine if a successful PCR reaction had taken place. Lane 3 contains PCR product from the Kanamycin plate L1 grid #14 and lane 4 contains PCR product from the master patch plate D3 grid #16. Bands were not seen in these lanes containing environmental bacteria, signaling an unsuccessful PCR. Lane 5 displays the negative water control without bands. Lane 6 shows the positive E. coli control PCR product with a band length of about 2,000bp (Figure 11). Discussion The study showed that no statistically significant difference existed between the amount of antibiotic resistant bacteria in the garbage disposal and laboratory sink and it also characterized all of the environmental bacteria as Gram negative. To determine the amount of bacteria located in the experimental areas, many tests were utilized to analyze the bacterium. Patch plates containing Tetracycline, Ampicillin, Kanamycin and LB were made in order to verify antibiotic resistant bacteria and growth. The plates with bacterial growth that was resistant to Ampicillin and Kanamycin were used in a statistical analysis to determine a correlation between the amounts of growth and the two environments. Our prediction that the amount of bacterial growth from the garbage disposal sink in Capitol Villa would be greater than the Lyman Briggs lab sink in C5 was refuted due to the Chi-squared Test for Independence that showed no statistically significant difference. We failed to reject the null hyp othesis that no difference existed between the amounts of antibiotic resistant bacteria found in each environment. A Chi-squared Test for Independence was run to compare the amounts of antibiotic resistant bacteria on the Ampicillin and Kanamycin plates. Tetracycline was not used because no data indicated resistance. The existence of Ampicillin and Kanamycin resistant bacteria in both the garbage disposal and the laboratory sink is unsurprising due to the widespread clinical use of both antibiotics over the past decades (Criswell, 2004). For Ampicillin, a total of 178 bacterial streaks grew between the two environments and a p-value of 0.74 was calculated. With one degree of freedom, the Chi-squared critical value of 3.84 obtained from a Chi-squared Distribution Table in comparison to the Chi-squared statistical value denoted no statistically significant difference. For Kanamycin, 162 streaks grew between the two environments and a p-value of 0.81 was calculated. With one degree of freedom, the a comparison of the Chi-squared critical value of 3.84 found from a Chi-squared Distribution Table to t he Chi-squared statistical value denoted no statistically significant difference as well. Therefore, the prediction that the garbage disposal sink would contain more antibiotic resistant bacteria than the laboratory sink was rejected. To further understand why bacteria were resistant, four tests were run to categorize the Gram identity of the environmental samples. The structure of the bacteria plays a large role in determining resistance. Importantly, it is easier for the plasmid DNA to penetrate a Gram negative bacterium due to the lack of an outer membrane around the peptidoglycan layer. The Gram staining process showed pink rod shaped bacterium, demonstrating that the bacteria was Gram negative. The KOH tests resulted in a viscous substance, indicating that all the environmental bacteria obtained from the garbage disposal and the laboratory sink were Gram negative. The MacConkey agar plates identified the bacteria to be Gram negative through growth on the plate. The growth on the plate was a pink color, signifying lactose fermentation from the bacteria. The environmental bacteria developed pink colonies on the EMB agar plates, further supporting the Gram negative identity and a low production of lactose fermen tation of the environmental bacteria gathered from the garbage disposal and laboratory sink. Gel electrophoresis was used in determining the existence and length of environmental plasmid DNA. The Miniprep isolated the plasmid DNA from the bacteria, but upon running the gel, it was discovered that no environmental plasmid DNA was present. The absence of bands

Opium (Papaver somniferum) Essay examples -- Botany

Opium (Papaver somniferum) The opium poppy has been used as a medicinal plant for centuries all over the world. The opium poppy plant belongs to the Papaveraceae family. The scientific name of the opium poppy is Papaver somniferum L., and it is native to Turkey. The plant has lobed leaves, milky sap and four to six petaled flowers with several stamens surrounding the ovary. The two sepals drop off when the petals unfold. The ovary then develops into a short, many seeded capsule that opens in dry weather. The small seeds of the opium poppy plant are dispersed by wind. The plant has five inch purple or white flowers on plants three to sixteen feet tall. It is and annual plant which needs to be planted only once for several years of harvest. There are many varieties of poppy plants grown other then the opium poppy, mostly for seasonings, oil, birdseed and attractive flowers. The poppy plants produce natural opiates. An opiate is defined as the drug derived from the opium poppy and are found in the milky substance extracted from the unripe seeds. The opiates are the best known narcotics. There are twenty different alkaloids derived from the opiates. Codeine and Morphine are the ones that are still in widespread use today. Codeine is a milder form of morphine and both are used today in the medical field for relieving pain. To obtain opium from Papaver somniferum is a very easy thing to do. It is a very common plant and is easy to purchase. The seeds can be planted and little care is needed to grow healthy plants. When the flowers turn to seed, the seed pods are slightly incised and a white milky liquid is dispersed. The liquid is allowed to seep out and dry for a few hours. The white liquid will turn to black when it is expo... ...for simple uses, the plant produces a drug that causes death and injury. The medicinal uses have been overlooked by people using opium for recreation, causes strict restrictions and laws to control it. The opium poppy has gained much attention all around the world. Reports Cited 1. Alcohol and Drugs Consumption: Psychotropic Drug: The varieties of psychotrophic drug: OPIUM, MORPHINE, HEROIN, and Related Synthetics: History (http://www.eb.com:180/cgi-bin/g?DocF=macro/5000/7/26.html&bold=on&sw=drug&keywords=psychotrophic%20drug&DBase=Articles&hits=10&pt=1&sort=relevance&config=config&firsthit=off). 2. Facts about opiates (http://www.arf.org/isd/pim/opiates.html) . 3. Opiates: High risk addiction (http://losangeles.dci.webpoint.com/health/osubopia.htm). 4. "Opium" Britannica Online (http://www-lj.eb.com:82/index.htcl/aDB/index_alpha/thisRow/151030/). Opium (Papaver somniferum) Essay examples -- Botany Opium (Papaver somniferum) The opium poppy has been used as a medicinal plant for centuries all over the world. The opium poppy plant belongs to the Papaveraceae family. The scientific name of the opium poppy is Papaver somniferum L., and it is native to Turkey. The plant has lobed leaves, milky sap and four to six petaled flowers with several stamens surrounding the ovary. The two sepals drop off when the petals unfold. The ovary then develops into a short, many seeded capsule that opens in dry weather. The small seeds of the opium poppy plant are dispersed by wind. The plant has five inch purple or white flowers on plants three to sixteen feet tall. It is and annual plant which needs to be planted only once for several years of harvest. There are many varieties of poppy plants grown other then the opium poppy, mostly for seasonings, oil, birdseed and attractive flowers. The poppy plants produce natural opiates. An opiate is defined as the drug derived from the opium poppy and are found in the milky substance extracted from the unripe seeds. The opiates are the best known narcotics. There are twenty different alkaloids derived from the opiates. Codeine and Morphine are the ones that are still in widespread use today. Codeine is a milder form of morphine and both are used today in the medical field for relieving pain. To obtain opium from Papaver somniferum is a very easy thing to do. It is a very common plant and is easy to purchase. The seeds can be planted and little care is needed to grow healthy plants. When the flowers turn to seed, the seed pods are slightly incised and a white milky liquid is dispersed. The liquid is allowed to seep out and dry for a few hours. The white liquid will turn to black when it is expo... ...for simple uses, the plant produces a drug that causes death and injury. The medicinal uses have been overlooked by people using opium for recreation, causes strict restrictions and laws to control it. The opium poppy has gained much attention all around the world. Reports Cited 1. Alcohol and Drugs Consumption: Psychotropic Drug: The varieties of psychotrophic drug: OPIUM, MORPHINE, HEROIN, and Related Synthetics: History (http://www.eb.com:180/cgi-bin/g?DocF=macro/5000/7/26.html&bold=on&sw=drug&keywords=psychotrophic%20drug&DBase=Articles&hits=10&pt=1&sort=relevance&config=config&firsthit=off). 2. Facts about opiates (http://www.arf.org/isd/pim/opiates.html) . 3. Opiates: High risk addiction (http://losangeles.dci.webpoint.com/health/osubopia.htm). 4. "Opium" Britannica Online (http://www-lj.eb.com:82/index.htcl/aDB/index_alpha/thisRow/151030/).

Taxation Assignment

Question 1: a>Tax treatment to an individual if his employer was to provide the following benefits in package 1: Rental of apartment $ Salary Airfare for home leave (1trip) (20% x 5000) 1,000 220,000 Employee’s remuneration 221,000 Rental of apartment (housing accommodation benefit) for a non- director will be assessed based on the lower of: the annual value of the accommodation provided or 10% of the employee’s remuneration inclusive of all other benefits except hotel accommodation.Therefore, housing benefit will be assessed at $22,100 because it is assessed based on the lower of (10% x 221,000= $22,100) or annual value of rental apartment of $60,000. Home leave passage According to Singapore tax law, home leave passage is provided by the employer to nonSingaporeans and non-permanent residents, the benefit is assessable to tax based on 20% of the cost to the employer.This concessionary treatment only can apply to ONE return leave passage per annum each for the employee and spouse, and TWO return passage for each child of employee per annum if child should be unmarried, under 16 years old or otherwise receiving full-time education or incapacitated. Therefore, in this package 1, Mr Rouse will be assessed for home leave passage at: 20% x 5,000= $1,000 Relocation passageAccording to Singapore tax law, relocation passages are by concession not a taxable benefit on the employee so that all the relocation expenses is not taxable benefit for Mr Rouse. b> Package 1: $ Salary Annual rental of apartment Home leave passage (20% x 5000) Statutory income Less: donation Assessable income Less : Relief Chargeable income Tax on 1st $160,000 Balance @ 17% (238,100 – 160,000) x 17% 220,000 22,100 1,000 243,100 NIL 243,100 (5,000) 238,100 15,500 13,277 28,777 Less : 20% tax rebate (capped at $2000) Net tax payable (2,000) 6,777 Package 2: $ Salary Statutory Income Less: donation Assessable income Less: Relief Chargeable income Tax in 1st $160,000 Balance @ 17 % 17% x (295,000-160,000) 300,000 300,000 NIL 300,000 (5,000) 295,000 15,500 22,950 38,450 Less : 20% tax rebate (capped at $2,000) Net tax payable (2,000) 36,450 c> Mr Rouse should choose package 1 because in this package, he can receive many benefits as well as many concessionary treatments that can reduce the net tax payable, in order to get higher return than in package 2. > Singapore is a country where the government uses many policies that include many benefits, treat with consideration to attract talents from many the other countries and tax law is not the exception. Therefore, Mr Rouse should choose or ask more benefits instead of only high salary such as house accommodation benefit, home leave passage, relocation passage, transportation benefit, etc†¦. to earn many concessionaries to minimize his statutory income as well as to reduce tax payable. Question 2: a>The relevant dates in shareholder’s continuity test are different for unabsorbed capital allowances and trade losses and donation.Unabsorbed capital allowances can be carried against future profits provided the shareholdings are substantially the same (50% or more) in the 2 relevant dates: The last day of the YA (31 Dec) it arose And The first day of the YA (1 Jan) it is utilized Trade losses and donations can be carried against future profits provided the shareholdings are substantially the same (50% or more) in the 2 relevant dates: The last day of the year it arose (31 Dec of the calendar year) And The first day of the YA it is utilized (1 Jan of YA) b> YA 2008: – Adjusted tax loss (trade loss) YA 2009: – Adjusted profit $40,000 $422,000The shareholders of Feathers Pte Ltd based on % are as follows: 31/12/2007 Ee Mei Sarah 60% 40% 30/9/2008 40% 60% 31/12/2008 40% 60% 1/1/2009 10% 90% Assumption: on 1 Jan 2009, Donald still holds 5000 shares (total shares are 50,000 shares) Therefore, Queens’s shareholders and their shareholdings are as follows: Number of share 31/12/2007 Donald Ee Mei Ee Mei 25,000 20,000 60% x 5,000 = 3000 Sarah 40% x 5,000 = 2000 Total number of 50,000 shares 30/9/2008 5,000 10,000 40% x 35,000 = 14,000 60% x 35,000 = 21,000 50,000 s at 31/12/2008 5,000 10,000 40% x 35,000 = 14,000 60% x 35,000 = 21,000 50,000 1/1/2009 5,000 40,000 10% x 5,000 = 500 90% x 5,000 = 4,500 50,000 Two relevant dates in shareholder’s continuity test for trade loss are 31 Dec 2007 and 1 Jan 2009. Queens’s shareholders and their shareholdings in % as follows: 31/12/2007 Donald Ee Mei 50% {(20,000 + 3,000)/ 50,000} x 100% = 46% Sarah (2000/ 50,000) x 100% = 4% 100% 1/1/2009 10% {(40,000 + 500)/ 50,000} x 100% = 81% (4,500/ 50,000) x 100% = 9% 100%Previous year’s trade loss (adjusted tax loss) in YA 2008 can be carried against YA 2009 current year’s profit because the shareholdings are substantially the same (50% or more) in the two relevant dates of 31/12/2007 and 1/1/2009. YA 2009: $ Adjusted profit Less: trade loss brought forward 422,000 (40,000) Assessable income/ chargeable income 382,000 > Conditions to qualify for the tax exemption for new start-up company: A â€Å"qualifying company† means a company incorporated in Singapore which for each of the first three years of assessment is resident in Singapore for that YA, and has its total share capital beneficially held directly by no more than 20 shareholders: ? ? All of whom are individuals throughout the basis period for that YA or At least one of whom is an individual shareholder holding at least 10% of the total number of issued ordinary shares of the company throughout the basis period for that YA.In the case of a company limited by guarantee: ? ? all of its members must be individuals throughout the basis period for that YA or at least one of its member is an individual throughout the basis period for that YA, and the contribution of that individual under the Memorandum of Association of the company to the assets of the company in the event of its being wound up, amounts to at least 10% of total contributions of the members of the company throughout the basis period for that YA.Question 3: a>The Singapore tax system is considered as a territorial system because income accruing in or derived from Singapore (Singapore sourced) or overseas income received or deemed received in Singapore is assessable to tax. In other words, income that is sourced outside Singapore is not chargeable to Singapore income tax if this overseas income is not received or deemed received in Singapore.One exception to this rule is dividend gain in Singapore. Under the new one-tier corporate tax system since 1 January 2003, tax will only be imposed at the corporate level and all dividends distributed by a Singapore tax resident company will be tax exempt for its shareholders. b> Assumption: basic period is 1/1/200x to 31/12/200x Ms Dinh Tam’s 2-year contract will be from 1/4/2006 to 31/3/2008.Year assessment of Physical presence in Residence Singapore/ period of employment YA 2007 1/4/2006- 31/12/2006 Resident Exercise of employment in Singapore is more than 183 days in the basic period YA 2008 1/1/2007- 31/12/2007 Resident Exercise of employment in Singapore is more than 183 days in the basic period YA 2009 1/1/2008- 31/3/2008 Non-resident Both periods of employment and physical presence are less than 183 days. Remarks c> Mr Tan KL, a Singapore resident, purchased a house in China. He rents it out and the rent is credited into his bank account in Hong Kong by the property agent.It means he receives a rental income in China and this income may be subject to tax in China remitted to Singapore is exempt from Singapore tax. In addition, according to Singapore tax law, all foreign sourced income remitted by INDIVIDUAL RESIDENT in Singapore on or after 1 January 2004 will be exempt from tax. d> Determine whether the following receipts would be considered as income for tax purposes: i>This income will be exempt from tax if Ah Kow is Singapore resident because this income may be taxed in Macau remitted to Singapore is exempt from Singapore tax.In addition, according to Singapore tax law, all foreign sourced income remitted by INDIVIDUAL RESIDENT in Singapore on or after 1 January 2004 will be exempt from tax. ii>   Profits made by a share broker from sale of shares is taxable income because shares are considered as his inventory to make profit therefore it is called revenue receipt for this share broker and that is subject to Singapore tax. iii> Samantha Lee, a teacher made a profit from the sale of her piano is exempt from tax if this piano is her fixed asset and Samantha Lee doesn’t repeat piano buy and sale transaction many times.It means this profit is capital receipt, not revenue receipt and so that it is not taxable. iv> Money received from an unlawful business in Singapore is taxable income because it is revenue receipt and income derived in Singapore so that it is subject t o tax in Singapore. v> Money received from sale of computer by a private school is exempt from tax because computer is considered as fixed asset of this private school. It means this income is capital receipt that is not taxable income.

The Quest for the Source of the Nile

In the mid-nineteenth century, European explorers and geographers were obsessed with the question: where does the Nile River begin? Many considered it to be the greatest geographic mystery of their day, and those who sought it became household names. Their actions and the debates that surrounded them intensified public interest in Africa and contributed to the colonization of the continent. The Nile River The Nile River itself is easy to trace. It runs northward from the city of Khartoum in Sudan through Egypt and drains into the Mediterranean. It is created, though, from the confluence of two other rivers, The White Nile and the Blue Nile. By the early nineteenth century, European explorers had shown that the Blue Nile, which supplies much of the water for the Nile, was a shorter river, arising only in neighboring Ethiopia. From then forward, they fixed their attention on the mysterious White Nile, which arose much further south on the Continent. A Nineteenth-Century Obsession By the mid-nineteenth century, Europeans had become obsessed with finding the source of the Nile. In 1857, Richard Burton and John Hannington Speke, who already disliked each other, set out from the east coast to find the much-rumored source of the White Nile. After several months of acrimonious travel, they discovered Lake Tanganyika, though reportedly it was their headman, a former slave known as Sidi Mubarak Bombay, who first spotted the lake (Bombay was essential to the success of the trip in many ways and went on to manage several European expeditions, becoming one of the many career headmen on whom explorers heavily relied.) As Burton was ill, and the two explorers were constantly locking horns, Speke proceeded north on his own, and there found Lake Victoria. Speke returned triumphantly, convinced he had found the source of the Nile, but Burton dismissed his claims, beginning one of the most divisive and public disputes of the age. The public at first strongly favored Speke, and he was sent on a second expedition, with another explorer, James Grant, and nearly 200 African porters, guards, and headmen. They found the White Nile but were unable to follow it up to Khartoum. In fact, it was not until 2004 that a team finally managed to follow the river from Uganda all the way to the Mediterranean. So, once again Speke returned unable to offer conclusive proof. A public debate was arranged between him and Burton, but when he shot and killed himself on the day of the debate, in what many believed was an act of suicide rather than the shooting accident it was officially proclaimed to be, support swung full circle to Burton and his theories.   The quest for conclusive proof continued for the next 13 years. Dr. David Livingstone and Henry Morton Stanley searched Lake Tanganyika together, disproving Burton’s theory, but it was not until the mid-1870s that Stanly finally circumnavigated Lake Victoria and explored the surrounding lakes, confirming Speke’s theory and solving the mystery, for a few generations at least. The Continuing Mystery As Stanley showed, the White Nile flows out of Lake Victoria, but the lake itself has several feeder rivers, and present-day geographers and amateur explorers still debate which of these is the true source of the Nile. In 2013, the question came to the fore again when the popular BBC car show, Top Gear, filmed an episode featuring the three presenters trying to find the source of the Nile while driving inexpensive station wagons, known in Britain as estate cars. Currently, most people agree the source is one of two small rivers, one of which arises in Rwanda, the other in neighboring Burundi, but it is a mystery that continues.