This blog is devoted to BIOL 6988, a graduate level seminar in the biological sciences at Youngstown State University. While targeted towards graduate students, BIOL 6988 actively incorporates undergraduate participants in their scholastic endeavors in the biological sciences. This blog is intended as a educational tool not just for YSU students and faculty, but for anyone who wishes to contribute to an active-learning environment.
This week's seminar guest is Dr. Acer, who is a post-doctoral associate in Dr. Johnston's laboratory. He will discussing his work with contaminated sediments of the Mahoning River. I will be the scribe for this presentation.
Dr. Acer presented a ton of preliminary data regarding the various bacteria, both aerobic and anaerobic, that degrade PAHs. Some of these appeared to be species of Pseudomonas. Why may this particular species be significant in the degradation of PAHs?
Dr. Acer’s research on PAH degradation is interesting because ongoing research in the subject can aide in bioremediation of contaminated ecosystems. Since PAHs are difficult to degrade due to their structure they exist in the environment for longer periods of time and pose significant threats to wildlife and human health without bioremediation. The preliminary research presented by Dr. Acer showed the microbial makeup from their study, mostly containing gammaproteobacteria. In regard to the discussion, Pseudomonas was a main component in the microbial analysis of samples. A 2009 study by the International Journal of Environmental Research and Public Health reviewed catabolic pathways capable of breaking down PAH structures in bacteria. Pseudomonas was also one of the most abundant bacteria in their study, showing catabolic processes that were able to break down multiple types of PAHs. The ability to break down these structures would, in theory, allow them to grow more readily in PAH contaminated environments than other bacterial species, though another study showed that their growth is restricted by contaminants.
Accumulation of carcinogenic compounds like PAH causes fish consumption bans and sediment contact advisories, and negatively impacts community health. Microbial degradation and bioremediation of PAHs would be a better alternative to using nasty chemical treatments, so hopefully Dr. Acer discovers a PAH-loving bacterium that is capable of degrading the pollutant. Like Jamielynn said, pseudomonas is highly abundant in samples taken from the Mahoning River. It is also very well studied and tends to not cause major illnesses in humans. Pseudomonas can thrive in the river, degrade PAH, and not cause an outbreak, which sound like it is qualified for the job of bioremediator.
As a Youngstown native, it is interesting to learn more about the pollution in the Mahoning River and even more interesting that Dr. Acer is doing work that may help solve the problem. I’ve always known that the Mahoning River was polluted growing up, but never knew that it was the 5th most contaminated river in the US which is rather alarming. Similar to other bacteria, pseudomonas are capable of using a large number of organic compounds as unique carbon and energy sources. This versatility allows this genus to be present in a multitude of various environments. For example, a study was conducted in China where a strain of pseudomonas was isolated (Pseudomonas sp. JM2). The researchers discovered that this strain is a high performance strain in the degradation of fluorene and phenanthrene (2 PAHs Dr. Acer also used) under extreme pH and temperature conditions. These researchers also added formate to the medium and discovered a three-fold increase in the microbial biomass of PAHs. Like Kyle mentioned, pseudomonas are not known to cause any significant illnesses so hopefully they can be used in some way (possibly along with formate) to effectively treat our polluted river.
I read that P. aeroginosa can produce surfactants, which then effectively solubilize the hydrophobic PAHs. This emulsification can increase the accessibility of the PAHs to other bacteria in nearby soils. More broadly speaking, Pseudomonas are ubiquitous and naturally break down PAHs, and I think increasing the efficiency of an already established metabolic pathway is much easier than creating a new one, or introducing a new genus to an ecosystem. I think there is a lot of potential in research and/or techniques that might maximize PAH breakdown by Pseudomonas.
I have always been aware of the gross amount of contamination in the Mahoning River, but as Dr. Acer said and Marissa mentioned, I never knew that it was the fifth most polluted river in the United States. From my understanding, the genus Pseudomonas is significant in its ability to degrade PAH’s due to their wide array of metabolic diversity as well as their ability to colonize on a variety of substrates. Furthermore, many bacteria have been found to degrade PAH’s with some being able to utilize a PAH as their sole carbon source. This is excellent for degradation of PAH’s such as naphthalene, anthracene, and acenaphthene.
I liked Dr. Acer presentation and analysis on Mahoning River that may mitigate the level of contamination caused by PAH that may pose health problems to both human and aquatic animals. I think Pseudomonas is significantly abundant genus in his finding for degrading PAHs due to their wide microbial diversity, abundance in microbial communities and resistance to most chemical remediation agents that might be present at contaminated Mahoning River
I may not be a Youngstown native but even in Western Pennsylvania where I am from, the rivers are heavily impacted by pollution, like the Mahoning River. People used to say that if you swam in the Beaver River, which is one of the dirtiest rivers around where I live, that you’d come out glowing. So I found Dr. Acer’s presentation noteworthy in that it may help to clean our nasty rivers and restore them to their former glory.
Pseudomonas may be one of the more significant PAH-degrading bacteria for a number of reasons. Pseudomonas is a very diverse genus of bacteria, most of which are not usually pathogenic so there would be little anticipated risk to human health in using it as a bioremediator. They are easy to culture in vitro, making it easy to grow them in the large quantities required for potentially cleaning up rivers. Pseudomonas species genome sequences are increasingly available, making them a well-known genus. They are also able to thrive in harsh conditions due to their hardy porin-containing cell wall, and they’ve already been found in large quantities in the Mahoning River so there would be no question as to whether they can survive its taxing environment.
I know that Dr. Acer’s presentation suggested the application of possibly introducing large quantities of the PAH-degrading bacteria into the Mahoning River but I came across an article which suggested use of the bacteria as a cheaper alternative to removing PAHs at water treatment facilities since PAH not only has unhealthy consequences for water and soil ecosystems but can also be harmful when ingested. PAHs are degraded into intermediates which are metabolized to substances which are mutagenic.
It was rather alarming learning the Mahoning River is the fifth most polluted river in the United States. Dr. Acer’s research is the beginning point for further investigation into PAH degradation. Different structures of PAH prove to be more difficult to degrade. In an aqueous setting, studies show PAHs containing two to four rings are more susceptible to biological breakdown and use. PAH structures that contain more than four rings become difficult to degrade due to a solid bound state and low volatility. Perhaps Dr. Acer’s future work can attempt to use the metabolic activity of genus pseudomonas in varying temperature settings. As Marisa said, this genus is known to thrive in a wide variety of environments. Varying temperatures can alter PAH structure. It is possible PAH degradation via pseudomonas metabolic activity can increase with a temperature change.
I always knew the Mahoning River was dirtier compared to other rivers, but I was not aware until this presentation that it is the fifth most polluted air in the U.S. A major contributing factor to this is the accumulation of PAH compounds, which have led to environmental concerns such as the presence of carcinogens and fish consumption advisory. Certain species, such as Pseudomonas, have been shown to help degrade these harmful compounds in Dr. Acer's study. An increase in species such as this could potentially result in a decrease in carcinogens and toxins in the Mahoning River and make it overall less of an environmental concern. Furthermore, it could help restore the condition of the wildlife living near or in the river. Because there is a higher level of Pseudomonas present in this river, we could see such results overtime and improve the quality of this river.
Dr. Acers presentation gave quantitative information on the sediment contamination of the Mahoning River. I knew that the Mahoning river had a “dirty” history but was unaware of the information provided during Dr. Acers presentation. PAH’s abundance in the Mahoning river is alarming due to their bioaccumulation and toxic, carcinogenic properties. PAH’s absorb into soil of organic-rich sediment and in water ecosystems which then accumulate in aquatic organisms and fish and in turn can ultimately affect humans. Most of the bacterial strains that have been found to degrade aromatic hydrocarbons belong to the genus Pseudomonas. They are significant in degrading PAH’s because they present a large potential for hydrocarbon degradation due to their diversity of metabolic activity and the amplitude of the genus in microbial communities, like the Mahoning River. Degrading these organic compounds by bioremediation with the use of microorganisms seems to be an excellent way to restore polluted sites. Also further research on exploring the communication, molecularly, between microbes and plants can be used to achieve this elimination of contaminants.
Dr. Acers presentation was very informative but the question I have is the type of plates he used and why? I believed he mentioned the type he used. Going off what Dr. Cooper asked that Pseudomonas naturally thrive and grow very easily. Seeing a lot of these types of bacteria is common but changing the incubation of these bacteria could have shown different results. Do you think there was any other type of bacteria he could have grown and seen changing the plates that would have altered the data?
Dr. Acer's presentation was very interesting about the Mahoning river and PAH’s abundance in the Mahoning river is alarming due to their toxic and carcinogenic properties. PAH degrading bacteria, Pseudomonas, was found in the river.
I was also quite surprised to hear how the pollution of the Mahoning river stacks up against the rest of the U.S. It seems that many of us were surprised to find out that it is considered to the the fifth most polluted river in the U.S. Before this seminar, I was not specifically familiar with PAHs. However, after seeing their structural relationships to benzene, it is not hard to believe that these compounds would be harmful to most organisms. Pseudomonas species are known for being easily accessible and easy to culture. In addition, this genus of gammaproteobacteria is known for demonstrating significant metabolic diversity. The psuedomonads seem to be found colonizing a broad range of niches in nature. Before degradation of PAHs was even being investigated, Pseudomonas species were already found to metabolize toluene, carbazole, and various other simple aromatic organic compounds and solvents. Since PAHs are basically just larger and more complex aromatic organic compounds, it would make sense that some Pseudomonas species would be able to degrade PAHs. Troy, I’m not sure exactly what you mean by the “type of plates” that he used. As far as the medium, he did use media containing amounts of three specific PAH compounds. These media were used to select for microbes that could metabolize the PAHs, which would presumably be toxic to some of the other microbes. In addition, removing some more preferable carbon sources from the medium would select only for those microbes that could metabolize and use the PAHs as an alternative carbon source.
Unfortunately I was unable to attend this Dr. Acer's presentation, but based on all your comments and feedback I was able to get the basis of his research. Very interesting! I guess I can relate with everyone when expressing my shock on learning that the Mahoning river is the 5th most polluted river in the United States.
Dr. Acer presented a ton of preliminary data regarding the various bacteria, both aerobic and anaerobic, that degrade PAHs. Some of these appeared to be species of Pseudomonas. Why may this particular species be significant in the degradation of PAHs?
ReplyDeleteThat should be "Why may this particular genus be significant in the degradation of PAHs?"
DeleteDr. Acer’s research on PAH degradation is interesting because ongoing research in the subject can aide in bioremediation of contaminated ecosystems. Since PAHs are difficult to degrade due to their structure they exist in the environment for longer periods of time and pose significant threats to wildlife and human health without bioremediation.
ReplyDeleteThe preliminary research presented by Dr. Acer showed the microbial makeup from their study, mostly containing gammaproteobacteria. In regard to the discussion, Pseudomonas was a main component in the microbial analysis of samples. A 2009 study by the International Journal of Environmental Research and Public Health reviewed catabolic pathways capable of breaking down PAH structures in bacteria. Pseudomonas was also one of the most abundant bacteria in their study, showing catabolic processes that were able to break down multiple types of PAHs. The ability to break down these structures would, in theory, allow them to grow more readily in PAH contaminated environments than other bacterial species, though another study showed that their growth is restricted by contaminants.
Accumulation of carcinogenic compounds like PAH causes fish consumption bans and sediment contact advisories, and negatively impacts community health. Microbial degradation and bioremediation of PAHs would be a better alternative to using nasty chemical treatments, so hopefully Dr. Acer discovers a PAH-loving bacterium that is capable of degrading the pollutant. Like Jamielynn said, pseudomonas is highly abundant in samples taken from the Mahoning River. It is also very well studied and tends to not cause major illnesses in humans. Pseudomonas can thrive in the river, degrade PAH, and not cause an outbreak, which sound like it is qualified for the job of bioremediator.
ReplyDeleteAs a Youngstown native, it is interesting to learn more about the pollution in the Mahoning River and even more interesting that Dr. Acer is doing work that may help solve the problem. I’ve always known that the Mahoning River was polluted growing up, but never knew that it was the 5th most contaminated river in the US which is rather alarming.
ReplyDeleteSimilar to other bacteria, pseudomonas are capable of using a large number of organic compounds as unique carbon and energy sources. This versatility allows this genus to be present in a multitude of various environments. For example, a study was conducted in China where a strain of pseudomonas was isolated (Pseudomonas sp. JM2). The researchers discovered that this strain is a high performance strain in the degradation of fluorene and phenanthrene (2 PAHs Dr. Acer also used) under extreme pH and temperature conditions. These researchers also added formate to the medium and discovered a three-fold increase in the microbial biomass of PAHs. Like Kyle mentioned, pseudomonas are not known to cause any significant illnesses so hopefully they can be used in some way (possibly along with formate) to effectively treat our polluted river.
I read that P. aeroginosa can produce surfactants, which then effectively solubilize the hydrophobic PAHs. This emulsification can increase the accessibility of the PAHs to other bacteria in nearby soils. More broadly speaking, Pseudomonas are ubiquitous and naturally break down PAHs, and I think increasing the efficiency of an already established metabolic pathway is much easier than creating a new one, or introducing a new genus to an ecosystem. I think there is a lot of potential in research and/or techniques that might maximize PAH breakdown by Pseudomonas.
ReplyDeleteI have always been aware of the gross amount of contamination in the Mahoning River, but as Dr. Acer said and Marissa mentioned, I never knew that it was the fifth most polluted river in the United States. From my understanding, the genus Pseudomonas is significant in its ability to degrade PAH’s due to their wide array of metabolic diversity as well as their ability to colonize on a variety of substrates. Furthermore, many bacteria have been found to degrade PAH’s with some being able to utilize a PAH as their sole carbon source. This is excellent for degradation of PAH’s such as naphthalene, anthracene, and acenaphthene.
ReplyDeleteI liked Dr. Acer presentation and analysis on Mahoning River that may mitigate the level of contamination caused by PAH that may pose health problems to both human and aquatic animals. I think Pseudomonas is significantly abundant genus in his finding for degrading PAHs due to their wide microbial diversity, abundance in microbial communities and resistance to most chemical remediation agents that might be present at contaminated Mahoning River
ReplyDeleteI may not be a Youngstown native but even in Western Pennsylvania where I am from, the rivers are heavily impacted by pollution, like the Mahoning River. People used to say that if you swam in the Beaver River, which is one of the dirtiest rivers around where I live, that you’d come out glowing. So I found Dr. Acer’s presentation noteworthy in that it may help to clean our nasty rivers and restore them to their former glory.
ReplyDeletePseudomonas may be one of the more significant PAH-degrading bacteria for a number of reasons. Pseudomonas is a very diverse genus of bacteria, most of which are not usually pathogenic so there would be little anticipated risk to human health in using it as a bioremediator. They are easy to culture in vitro, making it easy to grow them in the large quantities required for potentially cleaning up rivers. Pseudomonas species genome sequences are increasingly available, making them a well-known genus. They are also able to thrive in harsh conditions due to their hardy porin-containing cell wall, and they’ve already been found in large quantities in the Mahoning River so there would be no question as to whether they can survive its taxing environment.
I know that Dr. Acer’s presentation suggested the application of possibly introducing large quantities of the PAH-degrading bacteria into the Mahoning River but I came across an article which suggested use of the bacteria as a cheaper alternative to removing PAHs at water treatment facilities since PAH not only has unhealthy consequences for water and soil ecosystems but can also be harmful when ingested. PAHs are degraded into intermediates which are metabolized to substances which are mutagenic.
It was rather alarming learning the Mahoning River is the fifth most polluted river in the United States. Dr. Acer’s research is the beginning point for further investigation into PAH degradation. Different structures of PAH prove to be more difficult to degrade. In an aqueous setting, studies show PAHs containing two to four rings are more susceptible to biological breakdown and use. PAH structures that contain more than four rings become difficult to degrade due to a solid bound state and low volatility. Perhaps Dr. Acer’s future work can attempt to use the metabolic activity of genus pseudomonas in varying temperature settings. As Marisa said, this genus is known to thrive in a wide variety of environments. Varying temperatures can alter PAH structure. It is possible PAH degradation via pseudomonas metabolic activity can increase with a temperature change.
ReplyDeleteI always knew the Mahoning River was dirtier compared to other rivers, but I was not aware until this presentation that it is the fifth most polluted air in the U.S. A major contributing factor to this is the accumulation of PAH compounds, which have led to environmental concerns such as the presence of carcinogens and fish consumption advisory. Certain species, such as Pseudomonas, have been shown to help degrade these harmful compounds in Dr. Acer's study. An increase in species such as this could potentially result in a decrease in carcinogens and toxins in the Mahoning River and make it overall less of an environmental concern. Furthermore, it could help restore the condition of the wildlife living near or in the river. Because there is a higher level of Pseudomonas present in this river, we could see such results overtime and improve the quality of this river.
ReplyDeleteDr. Acers presentation gave quantitative information on the sediment contamination of the Mahoning River. I knew that the Mahoning river had a “dirty” history but was unaware of the information provided during Dr. Acers presentation.
ReplyDeletePAH’s abundance in the Mahoning river is alarming due to their bioaccumulation and toxic, carcinogenic properties. PAH’s absorb into soil of organic-rich sediment and in water ecosystems which then accumulate in aquatic organisms and fish and in turn can ultimately affect humans. Most of the bacterial strains that have been found to degrade aromatic hydrocarbons belong to the genus Pseudomonas. They are significant in degrading PAH’s because they present a large potential for hydrocarbon degradation due to their diversity of metabolic activity and the amplitude of the genus in microbial communities, like the Mahoning River. Degrading these organic compounds by bioremediation with the use of microorganisms seems to be an excellent way to restore polluted sites. Also further research on exploring the communication, molecularly, between microbes and plants can be used to achieve this elimination of contaminants.
Dr. Acers presentation was very informative but the question I have is the type of plates he used and why? I believed he mentioned the type he used. Going off what Dr. Cooper asked that Pseudomonas naturally thrive and grow very easily. Seeing a lot of these types of bacteria is common but changing the incubation of these bacteria could have shown different results. Do you think there was any other type of bacteria he could have grown and seen changing the plates that would have altered the data?
ReplyDeleteDr. Acer's presentation was very interesting about the Mahoning river and PAH’s abundance in the Mahoning river is alarming due to their toxic and carcinogenic properties. PAH degrading bacteria, Pseudomonas, was found in the river.
ReplyDeleteThe overwhelming majority of your comments on this topic are very well done! Thanks soooo much for your efforts! Keep up the good work.
ReplyDeleteI was also quite surprised to hear how the pollution of the Mahoning river stacks up against the rest of the U.S. It seems that many of us were surprised to find out that it is considered to the the fifth most polluted river in the U.S. Before this seminar, I was not specifically familiar with PAHs. However, after seeing their structural relationships to benzene, it is not hard to believe that these compounds would be harmful to most organisms.
ReplyDeletePseudomonas species are known for being easily accessible and easy to culture. In addition, this genus of gammaproteobacteria is known for demonstrating significant metabolic diversity. The psuedomonads seem to be found colonizing a broad range of niches in nature. Before degradation of PAHs was even being investigated, Pseudomonas species were already found to metabolize toluene, carbazole, and various other simple aromatic organic compounds and solvents. Since PAHs are basically just larger and more complex aromatic organic compounds, it would make sense that some Pseudomonas species would be able to degrade PAHs.
Troy, I’m not sure exactly what you mean by the “type of plates” that he used. As far as the medium, he did use media containing amounts of three specific PAH compounds. These media were used to select for microbes that could metabolize the PAHs, which would presumably be toxic to some of the other microbes. In addition, removing some more preferable carbon sources from the medium would select only for those microbes that could metabolize and use the PAHs as an alternative carbon source.
Unfortunately I was unable to attend this Dr. Acer's presentation, but based on all your comments and feedback I was able to get the basis of his research. Very interesting! I guess I can relate with everyone when expressing my shock on learning that the Mahoning river is the 5th most polluted river in the United States.
ReplyDelete